Sample records for range convection oven

  1. Convection automated logic oven control

    SciTech Connect (OSTI)

    Boyer, M.A.; Eke, K.I. [Apollo U.S.A. Inc., Orlando, FL (United States)] [Apollo U.S.A. Inc., Orlando, FL (United States)

    1998-03-01T23:59:59.000Z

    For the past few years, there has been a greater push to bring more automation to the cooling process. There have been attempts at automated cooking using a wide range of sensors and procedures, but with limited success. The authors have the answer to the automated cooking process; this patented technology is called Convection AutoLogic (CAL). The beauty of the technology is that it requires no extra hardware for the existing oven system. They use the existing temperature probe, whether it is an RTD, thermocouple, or thermistor. This means that the manufacturer does not have to be burdened with extra costs associated with automated cooking in comparison to standard ovens. The only change to the oven is the program in the central processing unit (CPU) on the board. As for its operation, when the user places the food into the oven, he or she is required to select a category (e.g., beef, poultry, or casseroles) and then simply press the start button. The CAL program then begins its cooking program. It first looks at the ambient oven temperature to see if it is a cold, warm, or hot start. CAL stores this data and then begins to look at the food`s thermal footprint. After CAL has properly detected this thermal footprint, it can calculate the time and temperature at which the food needs to be cooked. CAL then sets up these factors for the cooking stage of the program and, when the food has finished cooking, the oven is turned off automatically. The total time for this entire process is the same as the standard cooking time the user would normally set. The CAL program can also compensate for varying line voltages and detect when the oven door is opened. With all of these varying factors being monitored, CAL can produce a perfectly cooked item with minimal user input.

  2. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 1, Methodology

    SciTech Connect (OSTI)

    Not Available

    1993-11-01T23:59:59.000Z

    The Energy Policy and Conservation Act (P.L. 94-163), as amended, establishes energy conservation standards for 12 of the 13 types of consumer products specifically covered by the Act. The legislation requires the Department of Energy (DOE) to consider new or amended standards for these and other types of products at specified times. DOE is currently considering amending standards for seven types of products: water heaters, direct heating equipment, mobile home furnaces, pool heaters, room air conditioners, kitchen ranges and ovens (including microwave ovens), and fluorescent light ballasts and is considering establishing standards for television sets. This Technical Support Document presents the methodology, data, and results from the analysis of the energy and economic impacts of the proposed standards. This volume presents a general description of the analytic approach, including the structure of the major models.

  3. Convection?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution AndControlling Graphene's ElectronicnewConvection What

  4. Progressive Powder Coating: New Infrared Curing Oven at Metal Finishing Plant Increases Production by 50%

    SciTech Connect (OSTI)

    Not Available

    2003-05-01T23:59:59.000Z

    Progressive Powder Coating in Mentor, Ohio, is a metal finishing plant that uses a convection oven in its manufacturing process. In an effort to save energy and improve production, the company installed an infrared oven in between the powder coating booth and the convection oven on its production line. This installation allowed the plant to increase its conveyor line speed and increase production by 50 percent. In addition, the plant reduced its natural gas consumption, yielding annual energy savings of approximately$54,000. With a total project cost of$136,000, the simple payback is 2.5 years.

  5. Coke oven gas injection to blast furnaces

    SciTech Connect (OSTI)

    Maddalena, F.L.; Terza, R.R.; Sobek, T.F.; Myklebust, K.L. [U.S. Steel, Clairton, PA (United States)

    1995-12-01T23:59:59.000Z

    U.S. Steel has three major facilities remaining in Pennsylvania`s Mon Valley near Pittsburgh. The Clairton Coke Works operates 12 batteries which produce 4.7 million tons of coke annually. The Edgar Thomson Works in Braddock is a 2.7 million ton per year steel plant. Irvin Works in Dravosburg has a hot strip mill and a range of finishing facilities. The coke works produces 120 mmscfd of coke oven gas in excess of the battery heating requirements. This surplus gas is used primarily in steel re-heating furnaces and for boiler fuel to produce steam for plant use. In conjunction with blast furnace gas, it is also used for power generation of up to 90 MW. However, matching the consumption with the production of gas has proved to be difficult. Consequently, surplus gas has been flared at rates of up to 50 mmscfd, totaling 400 mmscf in several months. By 1993, several changes in key conditions provided the impetus to install equipment to inject coke oven gas into the blast furnaces. This paper describes the planning and implementation of a project to replace natural gas in the furnaces with coke oven gas. It involved replacement of 7 miles of pipeline between the coking plants and the blast furnaces, equipment capable of compressing coke oven gas from 10 to 50 psig, and installation of electrical and control systems to deliver gas as demanded.

  6. Oven wall panel construction

    DOE Patents [OSTI]

    Ellison, Kenneth (20 Avondale Cres., Markham, CA); Whike, Alan S. (R.R. #1, Caledon East, both of Ontario, CA)

    1980-04-22T23:59:59.000Z

    An oven roof or wall is formed from modular panels, each of which comprises an inner fabric and an outer fabric. Each such fabric is formed with an angle iron framework and somewhat resilient tie-bars or welded at their ends to flanges of the angle irons to maintain the inner and outer frameworks in spaced disposition while minimizing heat transfer by conduction and permitting some degree of relative movement on expansion and contraction of the module components. Suitable thermal insulation is provided within the module. Panels or skins are secured to the fabric frameworks and each such skin is secured to a framework and projects laterally so as slidingly to overlie the adjacent frame member of an adjacent panel in turn to permit relative movement during expansion and contraction.

  7. Ovenized microelectromechanical system (MEMS) resonator

    DOE Patents [OSTI]

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11T23:59:59.000Z

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  8. Solar Oven, Take One: FAIL | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    Solar Oven, Take One: FAIL Solar Oven, Take One: FAIL June 15, 2011 - 11:56am Addthis Our homemade solar oven. | Courtesy of Moon Choe Our homemade solar oven. | Courtesy of Moon...

  9. Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomass and Biofuels BiomassOutstanding-Long-Term-Liabilities

  10. Rapid baking characteristics and energy efficiency of an impingement air oven compared to a reel oven

    E-Print Network [OSTI]

    Smith, Lloyd Hobart

    1983-01-01T23:59:59.000Z

    those baked in the reel oven. Buna baked in t h e im pi ngement ove n wer e a pp rex imately 10X smaller in volume. Instron shear force measurements o f the change i n f i rmnes s t h a t r el a te to sta ling showed that the impingement baked buna... isture leve 1 s with in the oven. Modern reel ovens can be heated quickly, have easily adjustable temperature control and have high heat ing e ff ic iency. In 1 975, Smi t h was granted a patent for the "Jet Sweep" air impingement oven in which jets...

  11. Method for processing coke oven gas

    SciTech Connect (OSTI)

    Flockenhaus, C.; Meckel, J.F.; Wagener, D.

    1980-11-25T23:59:59.000Z

    Coke oven gas is subjected, immediately after the discharge thereof from coke ovens, and without any preliminary cooling operation or any purification operation other than desulfurization, to a catalytic cracking operation to form a hot cracked gas which is rich in hydrogen and carbon monoxide. The catalytic cracking reaction is carried out in the presence of a hydrogen-containing and/or CO2-containing gas, with a steam reforming catalyst.

  12. New process to avoid emissions: Constant pressure in coke ovens

    SciTech Connect (OSTI)

    Giertz, J.; Huhn, F. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). Inst. for Cokemaking and Fuel Technology; Hofherr, K. [Thyssen Stahl AG, Duisburg (Germany)

    1995-12-01T23:59:59.000Z

    A chamber pressure regulation (PROven), especially effective in regard to emission control problems of coke ovens is introduced for the first time. Because of the partial vacuum in the collecting main system, it is possible to keep the oven`s raw gas pressure constant on a low level over the full coking time. The individual pressure control for each chamber is assured directly as a function of the oven pressure by an immersion system controlling the flow resistance of the collecting main valve. The latter is a fixed-position design (system name ``FixCup``). By doing away with the interdependence of collecting main pressure and chamber pressure, a parameter seen as a coking constant could not be made variable. This opens a new way to reduce coke oven emissions and simultaneously to prevent the ovens from damage caused by air ingress into the oven.

  13. Multiple delivery cesium oven system for negative ion sources

    SciTech Connect (OSTI)

    Bansal, G.; Bhartiya, S.; Pandya, K.; Bandyopadhyay, M.; Singh, M. J.; Soni, J.; Gahlaut, A.; Parmar, K. G.; Chakraborty, A. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-02-15T23:59:59.000Z

    Distribution of cesium in large negative ion beam sources to be operational in ITER, is presently based on the use of three or more cesium ovens, which operate simultaneously and are controlled remotely. However, use of multiple Cs ovens simultaneously is likely to pose difficulties in operation and maintenance of the ovens. An alternate method of Cs delivery, based on a single oven distribution system is proposed as one which could reduce the need of simultaneous operation of many ovens. A proof of principle experiment verifying the concept of a multinozzle distributor based Cs oven has been carried out at Institute for Plasma Research. It is also observed that the Cs flux is not controlled by Cs reservoir temperature after few hours of operation but by the temperature of the distributor which starts behaving as a Cs reservoir.

  14. Prolongation technologies for campaign life of tall oven

    SciTech Connect (OSTI)

    Doko, Yoshiji; Saji, Takafumi; Kitayama, Yoshiteru; Yoshida, Shuhei [Sumitomo Metal Industries, Ltd., Kashima, Ibaraki (Japan). Kashima Steel Works

    1997-12-31T23:59:59.000Z

    In Kashima Steel Works, 25-year-old 7-meter-high coke ovens have damage on their walls. However, by using new methods of internal in-situ investigation, ceramic welding for the extended central and upper portions of coke ovens has prolonged the campaign life for over 40 years without large-scale hot repair. In this paper, introduction of these new methods, its application in Kashima and the policy of repairing the tall coke oven are reported.

  15. Pipeline charging of coke ovens with a preheated charge

    SciTech Connect (OSTI)

    Karpov, A.V.; Khadzhioglo, A.V.; Kuznichenko, V.M.

    1983-01-01T23:59:59.000Z

    Work to test a pipeline charging method was conducted at the Konetsk Coke Works (a PK-2K coke oven system with a single gas main, oven width 407 mm, height 4300 mm, effective column 20.0 cm/sub 3/). This method consists of transporting the heated coal charge to the ovens through a pipe by means of steam. the charge is transported by high pressure chamber groups, and loaded by means of systems equipped with devices for separation, withdrawal and treatment of the spent steam. The principal goal of the present investigation was to test technical advances in the emission-free charging of preheated charges. The problem was, first, to create a reliable technology for separation of the steam from the charge immediately before loading it into the oven and, second, to provide a total elimination of emissions, thereby protecting the environment against toxic substances.

  16. Problem of improving coke oven gas purification systems

    SciTech Connect (OSTI)

    Goldin, I.A.

    1982-01-01T23:59:59.000Z

    A discussion of the problems of improving desulfurization processes of coke oven gas was presented. Of particular interest were control systems and increasing capacity of the coke ovens. Included in the discussion were the vacuum-carbonate and arsenic-soda sulfur removal systems. Problems involved with these systems were the number of treatment operations, the volume of the reagents used, and the operation of equipment for naphthalene and cyanide removal.

  17. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1996-01-16T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  18. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  19. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1996-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  20. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1995-01-01T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  1. Innovative coke oven gas cleaning system for retrofit applications

    SciTech Connect (OSTI)

    Not Available

    1992-08-24T23:59:59.000Z

    The coke plant at the Sparrows Point Plant consist of three coke oven batteries and two coal chemical plants. The by-product coke oven gas (COG) consists primarily of hydrogen, methane, carbon monoxide, nitrogen and contaminants consisting of tars, light oils (benzene, toluene, and xylene) hydrogen sulfide, ammonia, water vapor and other hydrocarbons. This raw coke oven gas needs to be cleaned of most of its contaminants before it can be used as a fuel at other operations at the Sparrows Point Plant. In response to environmental concerns, BSC decided to replace much of the existing coke oven gas treatment facilities in the two coal chemical Plants (A and B) with a group of technologies consisting of: Secondary Cooling of the Coke oven Gas; Hydrogen Sulfide Removal; Ammonia Removal; Deacification of Acid Gases Removed; Ammonia Distillation and Destruction; and, Sulfur Recovery. This combination of technologies will replace the existing ammonia removal system, the final coolers, hydrogen sulfide removal system and the sulfur recovery system. The existing wastewater treatment, tar recovery and one of the three light oil recovery systems will continue to be used to support the new innovative combination of COG treatment technologies.

  2. A container for heat treating materials in microwave ovens

    DOE Patents [OSTI]

    Holcombe, C.E.; Dykes, N.L.; Kimrey, H.D. Jr.; Mills, J.E.

    1988-01-26T23:59:59.000Z

    The efficiency of a microwave oven of a conventional two-source configuration and energy level is increased by providing the oven with a container for housing a refractory material to be treated. The container is formed to top and bottom walls transparent to microwaves while the sidewalls, in a circular configuration, are formed of a nonmetallic material opaque to microwave radiation for reflecting the radiation penetrating the top and bottom walls radially inwardly into the center of the container wherein a casket of heat-insulating material is provided for housing the material to be heat treated. The reflection of the microwave radiation from the sidewalls increases the concentration of the microwaves upon the material being heat treated while the concentration of the microwaves upon the material being heat treated while the casket retains the heat to permit the heating of the material to a substantially higher temperature than achievable in the oven without the container.

  3. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1994-02-08T23:59:59.000Z

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  4. New process for coke-oven gas desulfurization

    SciTech Connect (OSTI)

    Currey, J.H. [Citizens Gas and Coke Utility, Indianapolis, IN (United States)

    1995-10-01T23:59:59.000Z

    With the EPA reclassifying spent iron oxide as a hazardous waste material in 1990, an alternative technology was sought for desulfurizing coke-oven gas. Vacasulf technology was adopted for reasons that included: producing of coke battery heating gas without further polishing and high-quality elemental sulfur; lowest operating cost in comparison with other methods; no waste products; and integrates with existing ammonia destruction facility. Vacasulf requires a single purchased material, potassium hydroxide, that reacts with carbon dioxide in coke-oven gas to form potassium carbonate which, in turn, absorbs hydrogen sulfide. Operation of the system has been successful following the resolution of relatively minor start-up problems.

  5. Operating and maintenance benefits of automated oven wall temperature measurement

    SciTech Connect (OSTI)

    Leuchtmann, K.P. [Thyssen Still Otto Anlagentechnik GmbH, Bochum (Germany); Hinz, D.; Bergbau, D. [Ruhrkohle Bergbau AG, Bottrop (Germany). Prosper Coking Plant; Platts, M. [Thyssen Still Otto Technical Services, Pittsburgh, PA (United States)

    1997-12-31T23:59:59.000Z

    For a very long time and regardless of all shortcomings associated with it, the manual measurement of the heating flue temperature has been the only method of monitoring the temperature prevailing in a coke oven battery and discovering weak points in the heating system. In the course of the last few years a number of automated temperature measuring systems have been developed that are intended to replace or supplement the manual heating flue measurement system. These measuring systems and their advantages/disadvantages are briefly described in this paper. Additionally, operational experience gathered with the oven chamber wall temperature measuring system is discussed in detail.

  6. New packing in absorption systems for trapping benzene from coke-oven gas

    SciTech Connect (OSTI)

    V.V. Grabko; V.M. Li; T.A. Shevchenko; M.A. Solov'ev [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

    2009-07-15T23:59:59.000Z

    The efficiency of benzene removal from coke-oven gas in absorption units OAO Alchevskkoks with new packing is assessed.

  7. Health-hazard evaluation report No. HETA-88-377-2120, Armco Coke Oven, Ashland Kentucky

    SciTech Connect (OSTI)

    Kinnes, G.M.; Fleeger, A.K.; Baron, S.L.

    1991-06-01T23:59:59.000Z

    In response to a request from the Oil, Chemical and Atomic Workers International Union, a study was made of possible hazardous working conditions at ARMCO Coke Oven (SIC-3312), Ashland, Kentucky. The facility produces about 1,000,000 tons of coke annually. Of the approximately 400 total employees at the coke oven site, 55 work in the by products area. Air quality sampling results indicated overexposure to both benzene (71432) and coal tar pitch volatiles (CTPVs). Airborne levels of benzene ranged as high as 117 parts per million (ppm) with three of 17 samples being above the OSHA limit of 1ppm. Airborne concentrations of CTPVs ranged as high as 0.38mg/cu m with two of six readings being above OSHA limit of 0.2mg/cu m. Several polynuclear aromatic hydrocarbons were also detected. The authors conclude that by products area workers are potentially overexposed to carcinogens, including benzene, CTPVs, and polynuclear aromatic hydrocarbons. An epidemiologic study is considered unlikely to yield meaningful information at this time, due to the small number of workers and the short follow up period. The authors recommend specific measures for reducing potential employee exposures, including an environmental sampling program, a preventive maintenance program, improved housekeeping procedures, and reducing exposure in operators' booths.

  8. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M. (Macungie, PA)

    1986-01-01T23:59:59.000Z

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  9. Convective heater

    DOE Patents [OSTI]

    Thorogood, R.M.

    1983-12-27T23:59:59.000Z

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

  10. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M. (Macungie, PA)

    1983-01-01T23:59:59.000Z

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  11. Development of advanced technology of coke oven gas drainage treatment

    SciTech Connect (OSTI)

    Higashi, Tadayuki; Yamaguchi, Akikazu; Ikai, Kyozou; Kamiyama, Hisarou; Muto, Hiroshi

    1996-12-31T23:59:59.000Z

    In April 1994, commercial-scale application of ozone oxidation to ammonia liquor (which is primarily the water condensing from coke oven gas) to reduce its chemical oxygen demand (COD) was started at the Nagoya Works of Nippon Steel Corporation. This paper deals with the results of technical studies on the optimization of process operating conditions and the enlargement of equipment size and the operating purification system.

  12. Automatic coke oven heating control system at Burns Harbor for normal and repair operation

    SciTech Connect (OSTI)

    Battle, E.T.; Chen, K.L. [Bethlehem Steel Corp., Burns Harbor, IN (United States); [Bethlehem Steel Corp., PA (United States)

    1997-12-31T23:59:59.000Z

    An automatic heating control system for coke oven batteries was developed in 1985 for the Burns Harbor No. 1 battery and reported in the 1989 Ironmaking Conference Proceedings. The original system was designed to maintain a target coke temperature at a given production level under normal operating conditions. Since 1989, enhancements have been made to this control system so that it can also control the battery heating when the battery is under repair. The new control system has improved heating control capability because it adjusts the heat input to the battery in response to anticipated changes in the production schedule. During a recent repair of this 82 oven battery, the pushing schedule changed from 102 ovens/day to 88 ovens/day, then back to 102 ovens/day, then to 107 ovens/day. During this repair, the control system was able to maintain the coke temperature average standard deviation at 44 F, with a maximum 75 F.

  13. The Videofil probe, a novel instrument to extend the coke oven service life

    SciTech Connect (OSTI)

    Gaillet, J.P.; Isler, D. [Centre de Pyrolyse de Marienau, Forbach (France)

    1997-12-31T23:59:59.000Z

    To prolong the service life of coke oven batteries, the Centre de Pyrolyse de Marienau developed the Videofil probe, a novel instrument to conduct diagnoses and to help repair operations of coke ovens. The Videofil probe is a flexible non-water-cooled endoscope which is used to locate flue wall damage and estimate its importance, to define the oven zones to repair and guide the repair work and to control the quality of the repair work and its durability.

  14. X-ray evaluation of coke-oven gas line deposits

    SciTech Connect (OSTI)

    Swain, Y.T.

    1983-08-01T23:59:59.000Z

    Control of coke-oven gas pipeline deposits has been facilitated through the use of an X-ray technique that provides quantitative data without disrupting plant operations.

  15. Takahax-Hirohax process for coke oven gas desulfurization

    SciTech Connect (OSTI)

    Gastwirth, H.; Miner, R.; Stengle, W.

    1981-01-01T23:59:59.000Z

    This paper describes the Takahax-Hirohax process to desulfurize coke oven gas and to produce an ammonium sulfate end product. A review is also made of current operating experience and recent technical developments. The Takahax-Hirohax process is extremely useful when the COG contains a suitable ammonia to sulfur ratio and when ammonium sulfate is a desirable end product. No contaminated effluent streams are emitted from the process. The process is simple, reliable, flexible, and responds easily to COG variations. 4 figures, 3 tables. (DP)

  16. A coke oven model including thermal decomposition kinetics of tar

    SciTech Connect (OSTI)

    Munekane, Fuminori; Yamaguchi, Yukio [Mitsubishi Chemical Corp., Yokohama (Japan); Tanioka, Seiichi [Mitsubishi Chemical Corp., Sakaide (Japan)

    1997-12-31T23:59:59.000Z

    A new one-dimensional coke oven model has been developed for simulating the amount and the characteristics of by-products such as tar and gas as well as coke. This model consists of both heat transfer and chemical kinetics including thermal decomposition of coal and tar. The chemical kinetics constants are obtained by estimation based on the results of experiments conducted to investigate the thermal decomposition of both coal and tar. The calculation results using the new model are in good agreement with experimental ones.

  17. SURFACE TENSION DRIVEN CONVECTION

    E-Print Network [OSTI]

    Wang, Shouhong

    SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS CONCLUDING REMARKS DYNAMIC TRANSITIONS OF SURFACE TENSION DRIVEN CONVECTION H.Dijkstra T. Sengul S. Wang #12;SURFACE TENSION DRIVEN CONVECTION DIJKSTRA, SENGUL, WANG INTRODUCTION LINEAR THEORY MAIN THEOREMS

  18. Desulphurization of coke oven gas by the Stretford Process

    SciTech Connect (OSTI)

    Plenderleith, J.

    1981-01-01T23:59:59.000Z

    The Stretford process is probably the most effective means available for removing hydrogen sulphide from gas streams. For streams which do not contain hydrogen cyanide or excessive oxygen it should be nearly ideal. However, the large volume of waste liquor generated by fixation of hydrogen cyanide has prevented its widespread adoption for coke oven gas treatment. Investigations of various proposals for treating the waste liquor indicate that the only practicable way of dealing with it is by reductive incineration. Although attempts to apply the Peabody-Holmes reductive incineration process have been disappointing, significant progress in overcoming some of its deficiencies has been made. The Zimpro wet oxidation process will provide a convenient method of treating the HCN scrubber effluent at No. 1 Plant. However, it will not treat the sodium based liquor from the Stretford plant. Its application to Stretford waste treatment is limited to situations where ammonium liquors and ammonium sulphate recovery facilities are available. Commissioning of this plant has been delayed while a defect in the air compressor supplied for the plant is being remedied. When the problem of liquid effluent disposal has been overcome, and if reagent chemicals continue to be available at reasonable prices, the Stretford process will be a good choice for coke oven gas desulphurization. 8 figures.

  19. Innovative coke oven gas cleaning system for retrofit applications

    SciTech Connect (OSTI)

    Not Available

    1992-10-16T23:59:59.000Z

    Bethlehem Steel Corporation (BSC), in conjunction with the Department of Energy (DOE) is conducting a Clean Coal Technology (CCT) project at its Sparrows Point, Maryland Coke Oven Plant. This project combines several existing technologies into an integrated system for removing impurities from Coke Oven Gas (COG) to make it an acceptable fuel. DOE is providing cost-sharing under a Cooperative Agreement with BSC. This Cooperative Agreement requires BSC to develop and conduct an Environmental Monitoring Plan (EMP) for the Clean Coal Technology project and to report the status of the EMP on a quarterly basis. This report is the third quarterly status report of the EMP. It covers the Environmental Monitoring Plan activities for the full year of 1991 from January 1, 1991 through December 31, 1991, including the forth quarter. See Sections 2, 3 and 4 for status reports of the Project Installation and Commissioning, the Environmental Monitoring activities and the Compliance Monitoring results for the period. Section 5 contains a list of Compliance Reports submitted to regulatory agencies during the period. The EMP describes in detail the environmental monitoring activities to be performed during the project execution. The purpose of the EMP is to: (1) document the extent of compliance of monitoring activities, i.e. those monitoring required to meet permit requirements, (2) confirm the specific impacts predicted in the National Environmental Policy Act documentation, and (3) establish an information base for the assessment of the environmental performance of the technology demonstrated by the project.

  20. Factors affecting coking pressures in tall coke ovens

    SciTech Connect (OSTI)

    Grimley, J.J.; Radley, C.E. [British Steel plc, Scunthorpe (United Kingdom). Scunthorpe Works

    1995-12-01T23:59:59.000Z

    The detrimental effects of excessive coking pressures, resulting in the permanent deformation of coke oven walls, have been recognized for many years. Considerable research has been undertaken worldwide in attempts to define the limits within which a plant may safely operate and to quantify the factors which influence these pressures. Few full scale techniques are available for assessing the potential of a coal blend for causing wall damage. Inference of dangerous swelling pressures may be made however by the measurement of the peak gas pressure which is generated as the plastic layers meet and coalesce at the center of the oven. This pressure is referred to in this report as the carbonizing pressure. At the Dawes Lane cokemaking plant of British Steel`s Scunthorpe Works, a large database has been compiled over several years from the regulator measurement of this pressure. This data has been statistically analyzed to provide a mathematical model for predicting the carbonizing pressure from the properties of the component coals, the results of this analysis are presented in this report.

  1. Process Parameters and Energy Use of Gas and Electric Ovens in Industrial Applications 

    E-Print Network [OSTI]

    Kosanovic, D.; Ambs, L.

    2000-01-01T23:59:59.000Z

    The study was conducted to evaluate the energy use of natural gas and electric ovens in the production of polymer bearings and components. Tests were conducted to evaluate and compare the performance of natural gas and electric ovens in the process...

  2. Process Parameters and Energy Use of Gas and Electric Ovens in Industrial Applications

    E-Print Network [OSTI]

    Kosanovic, D.; Ambs, L.

    The study was conducted to evaluate the energy use of natural gas and electric ovens in the production of polymer bearings and components. Tests were conducted to evaluate and compare the performance of natural gas and electric ovens in the process...

  3. Process for dissolving coke oven deposits comprising atomizing a composition containing N-methyl-2-pyrrolidone into the gas lines

    SciTech Connect (OSTI)

    Stafford, M.L.; Nicholson, G.M.

    1993-07-06T23:59:59.000Z

    A method is described for cleaning gas lines in coke oven batteries comprising atomizing a composition into the gas lines of coke oven batteries, where the composition comprises N-methyl-2-pyrrolidone.

  4. Coke oven gas desulphurization by the Carl Still process

    SciTech Connect (OSTI)

    Knight, R.E.

    1981-01-01T23:59:59.000Z

    The Steubenville East Coke Plant need a desulfurization process that would desulfurize an eventual 95 million standard cubic feet per day of coke oven gas from an inlet of 450 gr/DSCF to an outlet of 45 gr/DSCF of hydrogen sulfide. The Dravo/Still plant process was selected, due to the use of ammonia which was available in the gas, as the absorbing agent. It was also a proven process. Dravo/Still also was capable of building a sulfuric acid plant. The desulfurization efficiency of the plant has consistently provided an average final gas sulfur loading below the guaranteed 45 gr/DSCF. This removal efficiency has enabled production of an average of 4615 tons per day of 66/sup 0/Be acid. Also SO/sub 2/ to SO/sub 3/ conversion has averaged 98%. 3 figures. (DP)

  5. Method for removing hydrogen sulfide from coke oven gas

    SciTech Connect (OSTI)

    Ritter, H.

    1982-08-03T23:59:59.000Z

    An improved sulfur-ammonia process is disclosed for removing hydrogen sulfide from coke oven gases. In the improved process, a concentrator formerly used for standby operation is used at all normal times as an ammonia scrubber to improve the efficiency of gas separation during normal operation and is used as a concentrator for its intended standby functions during the alternative operations. In its normal function, the concentrator/scrubber functions as a scrubber to strip ammonia gas from recirculating liquid streams and to permit introduction of an ammonia-rich gas into a hydrogen sulfide scrubber to increase the separation efficiency of that unit. In the standby operation, the same concentrator/scrubber serves as a concentrator to concentrate hydrogen sulfide in a ''strong liquor'' stream for separate recovery as a strong liquor.

  6. Modelling of a coke oven heating wall M. Landreau, D. Isler, Centre de Pyrolyse de Marienau (CPM)

    E-Print Network [OSTI]

    Boyer, Edmond

    - 1 - Modelling of a coke oven heating wall M. Landreau, D. Isler, Centre de Pyrolyse de Marienau with thermomechanical modelling of a coke oven heating wall. The objective is to define the safe limits of coke oven of walls, roof and larry car, pre-stresses (anchoring system), lateral pressure due to coal pushing A 3D

  7. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    SciTech Connect (OSTI)

    Jensen, Michael

    2014-04-10T23:59:59.000Z

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  8. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Michael

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  9. Coke oven gas desulfurization: at Republic Steel's New Coking Facility, Warren, OH

    SciTech Connect (OSTI)

    Boak, S.C.; Prucha, D.G.; Turic, H.L.

    1981-01-01T23:59:59.000Z

    Our performance test indicates that the Sulfiban process is an effective method for removing H/sub 2/S from coke-oven gas. The process is able to handle variations in coke-oven gas flow and composition. Continuing efforts are underway to maintain optimum desulfurization conditions while trying to reduce waste production and MEA consumption. The problems which have prevented us from operating continuously have given us a better understanding of the process. This has contributed to better plant operations and greater equipment reliability for us to obtain continuous coke-oven gas desulfurization. 2 figures, 1 table.

  10. Seismic Sounding of Convection in the Sun

    E-Print Network [OSTI]

    Hanasoge, Shravan; Sreenivasan, Katepalli R

    2015-01-01T23:59:59.000Z

    Our Sun, primarily composed of ionized hydrogen and helium, has a surface temperature of 5777~K and a radius $R_\\odot \\approx 696,000$ km. In the outer $R_\\odot/3$, energy transport is accomplished primarily by convection. Using typical convective velocities $u\\sim100\\,\\rm{m\\,s^{-1}}$ and kinematic viscosities of order $10^{-4}$ m$^{2}$s$^{-1}$, we obtain a Reynolds number $Re \\sim 10^{14}$. Convection is thus turbulent, causing a vast range of scales to be excited. The Prandtl number, $Pr$, of the convecting fluid is very low, of order $10^{-7}$\\,--\\,$10^{-4}$, so that the Rayleigh number ($\\sim Re^2 Pr$) is on the order of $10^{21}\\,-\\,10^{24}$. Solar convection thus lies in extraordinary regime of dynamical parameters, highly untypical of fluid flows on Earth. Convective processes in the Sun drive global fluid circulations and magnetic fields, which in turn affect its visible outer layers ("solar activity") and, more broadly, the heliosphere ("space weather"). The precise determination of the depth of sola...

  11. Bethlehem Steel announces plans to control coke oven air and water pollution

    SciTech Connect (OSTI)

    Not Available

    1989-08-01T23:59:59.000Z

    Bethlehem Steel Corporation and the Maryland Department of the Environment have announced an agreement under which Bethlehem will spend an estimated $92-million at its Sparrows Points, Md., plant for technologically-advanced controls to further reduce air and water pollution, mainly from the plant's coke ovens. The two major systems include one to treat by-product coke oven gas and chemicals, and another to upgrade existing pushing emission controls on two older coke oven batteries. One of the new systems will replace most of the existing equipment that cleans gas and treats chemicals created by the coking process at the plant's three coke oven batteries. Because this system has the potential to greatly reduce sulfur dioxide and other pollutants, the United States Department of Energy (DOE) in September announced that its installation qualified for funding as part of the nationwide Innovative Clean Coal Technology Program.

  12. Additional Steam Traps Increase Production of a Drum Oven at a Petroleum Jelly Plant

    SciTech Connect (OSTI)

    Not Available

    2002-03-01T23:59:59.000Z

    Additional steam traps were installed on the drum oven at a petroleum jelly production facility at an ExxonMobil plant in Nigeria. The installation improved heat transfer and saved energy.

  13. Acoustic emission feedback control for control of boiling in a microwave oven

    DOE Patents [OSTI]

    White, Terry L. (Oak Ridge, TN)

    1991-01-01T23:59:59.000Z

    An acoustic emission based feedback system for controlling the boiling level of a liquid medium in a microwave oven is provided. The acoustic emissions from the medium correlated with surface boiling is used to generate a feedback control signal proportional to the level of boiling of the medium. This signal is applied to a power controller to automatically and continuoulsly vary the power applied to the oven to control the boiling at a selected level.

  14. Heating control methodology in coke oven battery at Rourkela Steel Plant

    SciTech Connect (OSTI)

    Bandyopadhyay, S.S.; Parthasarathy, L.; Gupta, A.; Bose, P.R.; Mishra, U.

    1996-12-31T23:59:59.000Z

    A methodology of heating control was evolved incorporating temperature data generated through infra-red sensor at quenching station and thermocouples specially installed in the gooseneck of coke oven battery No. 3 of RSP. Average temperature of the red-hot coke as pushed helps in diagnosis of the abnormal ovens and in setting the targeted battery temperature. A concept of coke readiness factor (Q) was introduced which on optimization resulted in lowering the specific heat consumption by 30 KCal/Kg.

  15. Development of automatic operation system for coke oven machines at Yawata Works of Nippon Steel Corporation

    SciTech Connect (OSTI)

    Matsunaga, Masao; Uematsu, Hiroshi; Nakagawa, Yoji; Ishiharaguchi, Yuji

    1995-12-01T23:59:59.000Z

    The coke plant is a working environment involving heavy dust emissions, high heat and demanding physical labor. The labor-saving operation of the coke plant is an essential issue from the standpoints of not only improvement in working environment, but also reduction in fixed cost by enhancement of labor productivity. Under these circumstances, Nippon Steel has implemented the automation of coke oven machines. The first automatic operation system for coke oven machinery entered service at Oita Works in 1992, followed by the second system at the No. 5 coke oven battery of the coke plant at Yawata Works. The Yawata automatic operation system is characterized by the installation of coke oven machinery to push as many as 140 ovens per day within a short cycle time, such as a preliminary ascension pipe cap opening car and cycle time simulator by the manned operation of the pusher, which is advantageous from the standpoint of investment efficiency, and by the monitoring of other oven machines by the pusher. These measures helped to reduce the manpower requirement to 2 persons per shift from 4 persons per shift. The system entered commercial operation in March, 1994 and has been smoothly working with an average total automatic rate of 97%. Results from the startup to recent operation of the system are reported below.

  16. A numerical study of orographic effects on moist convection

    E-Print Network [OSTI]

    Smith, Robert Doyle

    1972-01-01T23:59:59.000Z

    based on a typical synoptic situation across the mountain range of northern Honshu, Japan. Wind shear, stability~ and moisture were varied from the basic situation to observe the effects of induced vertical motion on the different clouds which formed... forecaster in Japan. Convective systems were noted as they crossed the Sea oi' Japan and changes to these systems ovserved as they crossed the mountain ranges of Japan. Some convective systems would move across the Sea of Japan caus1ng consecutive reports...

  17. Development of a high-temperature oven for the 28 GHz electron cyclotron resonance ion source

    SciTech Connect (OSTI)

    Ohnishi, J., E-mail: ohnishi@riken.jp; Higurashi, Y.; Kidera, M.; Ozeki, K.; Nakagawa, T. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)] [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)

    2014-02-15T23:59:59.000Z

    We have been developing the 28 GHz ECR ion source in order to accelerate high-intensity uranium beams at the RIKEN RI-beam Factory. Although we have generated U{sup 35+} beams by the sputtering method thus far, we began developing a high-temperature oven with the aim of increasing and stabilizing the beams. Because the oven method uses UO{sub 2}, a crucible must be heated to a temperature higher than 2000?°C to supply an appropriate amount of UO{sub 2} vapor to the ECR plasma. Our high-temperature oven uses a tungsten crucible joule-heated with DC current of approximately 450 A. Its inside dimensions are ?11 mm × 13.5 mm. Since the crucible is placed in a magnetic field of approximately 3 T, it is subject to a magnetic force of approximately 40 N. Therefore, we used ANSYS to carefully design the crucible, which was manufactured by machining a tungsten rod. We could raise the oven up to 1900?°C in the first off-line test. Subsequently, UO{sub 2} was loaded into the crucible, and the oven was installed in the 28 GHz ECR ion source and was tested. As a result, a U{sup 35+} beam current of 150 ?A was extracted successfully at a RF power of approximately 3 kW.

  18. Use of ethylenediamine to remove hydrogen sulfide from coke oven gas

    SciTech Connect (OSTI)

    Marakhovskii, L.F.; Popov, A.A.; Rezunenko, Yu.I.

    1983-01-01T23:59:59.000Z

    The investigations of the equilibrium absorption of H/sub 2/S by an EDA solution which show that the solubility of hydrogen sulfide in ethylenediamine solutions is almost twice that in monoethanolamine solutions. Ethylenediamine may be used as an absorber for thorough removal of H/sub 2/S from coke oven gas in the presence of CO/sub 2/ and HCN. The hydrogen cyanide of coke oven gas, having practically no effect on the equilibrium absorption of H/sub 2/S and CO/sub 2/, may in this case be recovered in the form of ethylenethiourea - a marketable byproduct.

  19. The use of ethylenediamine to remove hydrogen sulfide from coke oven gas

    SciTech Connect (OSTI)

    Marakhovskii, L.F.; Rezunenko, Y.I.; Popov, A.A.

    1983-01-01T23:59:59.000Z

    The investigations of the equilibrium absorption of H/sub 2/S by an EDA solution showed the solubility of hydrogen sulfide in ethylenediamine solutions is almost twice that in monoethanolamine solutions. Ethylenediamine may be used as an absorber for thorough removal of H/sub 2/S from coke oven gas in the presence of CO/sub 2/ and HCN. The hydrogen cyanide of coke oven gas, having practically no effect on the equilibrium absorption of H/sub 2/S and CO/sub 2/, may in this case be used in the form of ethylenethiourea - a marketable byproduct.

  20. Convective Cloud Lifecycles Lunchtime seminar

    E-Print Network [OSTI]

    Plant, Robert

    Convective Cloud Lifecycles Lunchtime seminar 19th May 2009 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations Why Conclusions Convective Cloud Lifecycles ­ p.1/3 #12;Why bother? Convective Cloud Lifecycles ­ p.2/3 #12;Some

  1. Hydrogen production from steam reforming of coke oven gas and its utility for indirect reduction of iron oxides in blast

    E-Print Network [OSTI]

    Leu, Tzong-Shyng "Jeremy"

    of coal and coke are consumed for heating and reducing iron oxides [2,3]. As a result, BFs have becomeHydrogen production from steam reforming of coke oven gas and its utility for indirect reduction 2012 Available online 18 June 2012 Keywords: Steam reforming Hydrogen and syngas production Coke oven

  2. Extra Crispy OvenFried Drumsticks 3 cups cornflake cereal, crushed

    E-Print Network [OSTI]

    Jawitz, James W.

    Extra Crispy OvenFried Drumsticks 3 cups cornflake cereal, crushed 1/3 cup grated Parmesan pepper sauce 8 chicken drumsticks, skinned Vegetable cooking spray 1. Combine buttermilk and hot pepper sauce in an extralarge ziptop freezer bag. Add chicken drumsticks, turning to coat. Place bag

  3. PROCESS PARAMETERS AND ENERGY USE OF GAS AND ELECTRIC OVENS IN INDUSTRIAL APPLICATIONS

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    . BACKGROUND This paper will evaluate current practices of clients in the New England/New York whichPROCESS PARAMETERS AND ENERGY USE OF GAS AND ELECTRIC OVENS IN INDUSTRIAL APPLICATIONS Dr for Energy Efficiency and Renewable Energy Department of Mechanical and Industrial Engineering University

  4. Innovative coke oven gas cleaning system for retrofit applications. Volume 1, Public design report

    SciTech Connect (OSTI)

    Not Available

    1994-05-24T23:59:59.000Z

    This Public Design Report provides, in a single document, available nonproprietary design -information for the ``Innovative Coke Oven Gas Cleaning System for Retrofit Applications`` Demonstration Project at Bethlehem Steel Corporation`s Sparrows Point, Maryland coke oven by-product facilities. This project demonstrates, for the first time in the United States, the feasibility of integrating four commercially available technologies (processes) for cleaning coke oven gas. The four technologies are: Secondary Gas Cooling, Hydrogen Sulfide and Ammonia Removal, Hydrogen Sulfide and Ammonia Recovery, and Ammonia Destruction and Sulfur Recovery. In addition to the design aspects, the history of the project and the role of the US Department of,Energy are briefly discussed. Actual plant capital and projected operating costs are also presented. An overview of the integration (retrofit) of the processes into the existing plant is presented and is followed by detailed non-proprietary descriptions of the four technologies and their overall effect on reducing the emissions of ammonia, sulfur, and other pollutants from coke oven gas. Narrative process descriptions, simplified process flow diagrams, input/output stream data, operating conditions, catalyst and chemical requirements, and utility requirements are given for each unit. Plant startup provisions, environmental considerations and control monitoring, and safety considerations are also addressed for each process.

  5. What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)

    SciTech Connect (OSTI)

    Jensen, Michael [BNL Environmental Sciences

    2014-02-19T23:59:59.000Z

    Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

  6. Natural convection heat transfer within horizontal spent nuclear fuel assemblies

    SciTech Connect (OSTI)

    Canaan, R.E.

    1995-12-01T23:59:59.000Z

    Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.

  7. VARIATION OF STELLAR ENVELOPE CONVECTION AND OVERSHOOT WITH METALLICITY

    SciTech Connect (OSTI)

    Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)] [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2013-04-10T23:59:59.000Z

    We examine how metallicity affects convection and overshoot in the superadiabatic layer of main sequence stars. We present results from a grid of three-dimensional radiation hydrodynamic simulations with four metallicities (Z = 0.040, 0.020, 0.010, 0.001), and spanning a range in effective temperature (4950 < T{sub eff} < 6230). We show that changing the metallicity alters properties of the convective gas dynamics, and the structure of the superadiabatic layer and atmosphere. Our grid of simulations shows that the amount of superadiabaticity, which tracks the transition from efficient to inefficient convection, is sensitive to changes in metallicity. We find that increasing the metallicity forces the location of the transition region to lower densities and pressures, and results in larger mean and turbulent velocities throughout the superadiabatic region. We also quantify the degree of convective overshoot in the atmosphere, and show that it increases with metallicity as well.

  8. Coke oven doors: Historical methods of emission control and evaluation of current designs

    SciTech Connect (OSTI)

    Pettrey, J.O.; Greene, D.E. (Armco Steel Co., Middletown, OH (United States))

    1993-01-01T23:59:59.000Z

    The containment of oven door leakage has presented challenges to coke producers for many years as the requirements of environmental regulatory agencies have become increasingly stringent. A description and evaluation of past door modifications, leakage control methodologies and luting practices on Armco Steel Company, L.P.'s Ashland No. 4 Battery is detailed to provide a background for recent work, and to expand the industry's technology base. The strict door leakage standards of the 1990 amendments to the USA Clean Air Act has prompted additional technical studies. Both a joint Armco committee's evaluation of successful systems world wide and test door installations at Ashland were incorporated to determine compliance strategy. The eventual installation of Ikio Model II coke oven doors, along with modifications to ancillary equipment, has resulted in door leakage rates approaching zero. Associated methods, problems, results and evaluations are discussed.

  9. Mathematical modeling of clearance between wall of coke oven and coke cake

    SciTech Connect (OSTI)

    Nushiro, K.; Matsui, T.; Hanaoka, K.; Igawa, K.; Sorimachi, K.

    1995-12-01T23:59:59.000Z

    A mathematical model was developed for estimating the clearance between the wall of the coke oven and the coke cake. The prediction model is based on the balance between the contractile force and the coking pressure. A clearance forms when the contractile force exceeds the coking pressure in this model. The contractile force is calculated in consideration of the visco-elastic behavior of the thermal shrinkage of the coke. The coking pressure is calculated considering the generation and dispersion of gas in the melting layer. The relaxation time off coke used in this model was obtained with a dilatometer under the load application. The clearance was measured by the laser sensor, and the internal gas pressure was measured in a test oven. The clearance calculated during the coking process were in good agreement with the experimental results, which supported the validity of the mathematical model.

  10. Choosing a coke-oven gas desulfurization system: a review of current technology

    SciTech Connect (OSTI)

    Lynch, P.A.

    1982-12-01T23:59:59.000Z

    Installation of coke-oven gas desulphurizing systems is primarily the result of air pollution control regulations. Although not currently profitable, operating costs can be minimized by choosing the technology most suited to the particular application. The Stretford Holmes, Takahax/Hirohax, Koppers Vacuum Carbonate, Sulfiban and Dravo/Still processes are discussed, together with criteria for economic analysis based on technical and by-product market evaluations.

  11. Operational improvements at Jewell Coal and Coke Company`s non-recovery ovens

    SciTech Connect (OSTI)

    Ellis, C.E.; Pruitt, C.W.

    1995-12-01T23:59:59.000Z

    Operational improvements at Jewell Coal and Coke Company over the past five years includes safety and environmental concerns, product quality, equipment availability, manpower utilization, and productivity. These improvements with Jewell`s unique process has allowed Jewell Coal and Coke Company to be a consistent, high quality coke producer. The paper briefly explains Jewell`s unique ovens, their operating mode, improved process control, their maintenance management program, and their increase in productivity.

  12. Method of washing hydrogen sulfide from coke oven gas by the ammonium sulfide method

    SciTech Connect (OSTI)

    Ritter, H.

    1985-05-21T23:59:59.000Z

    An improved coke oven gas washing process for removing hydrogen sulfide is proposed wherein the coke oven gas is treated in a hydrogen sulfide scrubber by counterflow with an aqueous ammonia wash water. A stream of aqueous weak ammonia liquor is cooled and sprayed through nozzles in the mid-region of the hydrogen sulfide scrubber. A quantity of aqueous ammonia liquor, corresponding to the quantity which is sprayed through the said nozzles, is withdrawn from the hydrogen sulfide scrubber at a level below the nozzles and is introduced into the top of the said hydrogen sulfide scrubber. Ammonia vapor released at the nozzles has a higher partial pressure than the ammonia partial pressure of the coke oven gas in the region of the nozzle. The aqueous ammonia liquor from the deacidifier is the source of the cooled aqueous ammonia liquor which is introduced through the nozzles. A portion of the aqueous ammonia liquor from the deacidifier is introduced directly into the top of the hydrogen sulfide scrubber as a portion of the required aqueous ammonia wash water.

  13. Design and operation of the coke-oven gas sulfur removal facility at Geneva Steel

    SciTech Connect (OSTI)

    Havili, M.U.; Fraser-Smyth, L.L.; Wood, B.W. [Geneva Steel, Provo, UT (United States)

    1996-02-01T23:59:59.000Z

    The coke-oven gas sulfur removal facility at Geneva Steel utilizes a combination of two technologies which had never been used together. These two technologies had proven effective separately and now in combination. However, it brought unique operational considerations which has never been considered previously. The front end of the facility is a Sulfiban process. This monoethanolamine (MEA) process effectively absorbs hydrogen sulfide and other acid gases from coke-oven gas. The final step in sulfur removal uses a Lo-Cat II. The Lo-Cat process absorbs and subsequently oxidizes H{sub 2}S to elemental sulfur. These two processes have been effective in reducing sulfur dioxide emissions from coke-oven gas by 95%. Since the end of the start-up and optimization phase, emission rate has stayed below the 104.5 lb/hr limit of equivalent SO{sub 2} (based on a 24-hr average). In Jan. 1995, the emission rate from the sulfur removal facility averaged 86.7 lb/hr with less than 20 lb/hr from the Econobator exhaust. The challenges yet to be met are decreasing the operating expenses of the sulfur removal facility, notably chemical costs, and minimizing the impact of the heating system on unit reliability.

  14. Utilizing secondary heat to heat wash oil in the coke-oven gas desulfurization division

    SciTech Connect (OSTI)

    Volkov, E.L.

    1981-01-01T23:59:59.000Z

    Removal of hydrogen sulfide from the coke-oven gas by the vacuum-carbonate method involves significant energy costs, comprising about 47% of the total costs of the process. This is explained by the significant demand of steam for regeneration of the wash oil, the cost of which exceeds 30% of the total operating costs. The boiling point of the saturated wash oil under vacuum does not exceed 70/sup 0/C, thus the wash oil entering the regenerator can be heated either by the direct coke-oven gas or by the tar supernatant from the gas collection cycle. Utilizing the secondary heat of the direct coke-oven gas and the tar supernatant liquor (the thermal effect is approximately the same) to heat the wash oil from the gas desulfurization shops significantly improves the industrial economic indices. Heating the wash oil from gas desulfurization shops using the vacuum-carbonate method by the heat of the tar supernatant liquor may be adopted at a number of coking plants which have a scarcity of thermal resources and which have primary coolers with vertical tubes.

  15. Final environmental information volume for the coke oven gas cleaning project at the Bethlehem Steel Corporation Sparrows Point Plant

    SciTech Connect (OSTI)

    Not Available

    1990-04-24T23:59:59.000Z

    Bethelehem Steel Corporation (BSC) is planning to conduct a demonstration project involving an integrated system that can be retrofitted into coke oven gas handling systems to address a variety of environmental and operational factors in a more cost-effective manner. Successful application of this technology to existing US coke plants could: (1) reduce emissions of sulfur dioxide, cyanide, and volatile organic compounds (including benzene) (2) reduce the cost and handling of processing feed chemicals, (3) disposal costs of nuisance by-products and (4) increase reliability and reduce operation/maintenance requirements for coke oven gas desulfurization systems. The proposed system will remove sulfur from the coke oven gas in the form of hydrogen sulfide using the ammonia indigenous to the gas as the primary reactive chemical. Ammonia and hydrogen cyanide are also removed in this process. The hydrogen sulfide removed from the coke oven gas in routed to a modified Claus plant for conversion to a saleable sulfur by-product. Ammonia and hydrogen cyanide will be catalytically converted to hydrogen, nitrogen, carbon dioxide, and carbon monoxide. The tail gas from the sulfur recovery unit is recycled to the coke oven gas stream, upstream of the new gas cleaning system. The proposed demonstration project will be installed at the existing coke oven facilities at BSC's Sparrows Point Plant. This volume describes the proposed actions and the resulting environmental impacts. 21 refs., 19 figs., 9 tabs.

  16. Analysis of Cloud-resolving Simulations of a Tropical Mesoscale Convective System Observed during TWP-ICE: Vertical Fluxes and Draft Properties in Convective and Stratiform Regions

    SciTech Connect (OSTI)

    Mrowiec, Agnieszka A.; Rio, Catherine; Fridlind, Ann; Ackerman, Andrew; Del Genio, Anthony D.; Pauluis, Olivier; Varble, Adam; Fan, Jiwen

    2012-10-02T23:59:59.000Z

    We analyze three cloud-resolving model simulations of a strong convective event observed during the TWP-ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large-scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ~10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ~0.5 independent of species, and the ratio of downdraft to updraft mass flux is ~0.5-0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ~10% (graupel) to ~90% (cloud ice). These findings may lead to improved convection parameterizations.

  17. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.; Yamaguchi, K.

    1983-01-01T23:59:59.000Z

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  18. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Natural convection can provide adequate heat distribution in many situtations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others or to reduce the number of heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures is predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Natural convective loops that can occur in buildings are described and a few design guidelines are presented.

  19. Total lightning observations of severe convection over North Texas

    E-Print Network [OSTI]

    McKinney, Christopher Michael

    2009-05-15T23:59:59.000Z

    Density GSD Gridded Source Density LDAR Lightning Detection and Ranging MCS Mesoscale Convective System MSI Mesocyclone Strength Index MxFED Maximum Flash Extent Density MxFIDT Maximum Flash Initiation Density Total MxGSD Maximum Gridded Source.......................................................................................... 1 1.2 Background ....................................................................................... 4 1.3 Thesis Objectives and Hypothesis...................................................... 19 2. DATA AND METHODOLOGY...

  20. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Natural convection can provide adequate heat distribution in many situations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others. Natural convection can also be used to reduce the number of auxiliary heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures are predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Experimental results are summarized based on the monitoring of 15 passive solar buildings which employ a wide variety of geometrical configurations including natural convective loops.

  1. Reduction of NO[sub x] emissions coke oven gas combustion process

    SciTech Connect (OSTI)

    Terza, R.R. (USS Clairton Works, PA (United States)); Sardesai, U.V. (Westfield Engineering and Services, Inc., Houston, TX (United States))

    1993-01-01T23:59:59.000Z

    The paper describes by-product processing at Clairton Works which uses a unique cryogenic technology. Modifications to the desulfurization facility, nitrogen oxide formation in combustion processes (both thermal and fuel NO[sub x]), and the boilers plants are described. Boilers were used to study the contribution of fuel NO[sub x] formation during the combustion of coke oven gas. Results are summarized. The modifications made to the desulfurization facility resulted in the overall H[sub 2]S emission being reduced by 2-4 grains/100scf and the NO[sub x] emission being reduced by 21-42% in the boiler stacks.

  2. Coke oven gas treatment and by-product plant of Magnitogorsk Integrated Iron and Steel Works

    SciTech Connect (OSTI)

    Egorov, V.N.; Anikin, G.J. [Magnitogorsk Integrated Iron and Steel Works, (Russian Federation); Gross, M. [Krupp Koppers GmbH, Essen (Germany)

    1995-12-01T23:59:59.000Z

    Magnitogorsk Integrated Iron and Steel Works, Russia, decided to erect a new coke oven gas treatment and by-product plant to replace the existing obsolete units and to improve the environmental conditions of the area. The paper deals with the technological concept and the design requirements. Commissioning is scheduled at the beginning of 1996. The paper describes H{sub 2}S and NH{sub 3} removal, sulfur recovery and ammonia destruction, primary gas cooling and electrostatic tar precipitation, and the distributed control system that will be installed.

  3. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, J.C.; Hardee, H.C.; Striker, R.P.

    1984-01-09T23:59:59.000Z

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

  4. March 1980 / Vol. 5, No. 3 / OPTICS LETTERS 117 Disk-shaped heat-pipe oven used for lithium excited-state

    E-Print Network [OSTI]

    Stroud, Carlos R.

    March 1980 / Vol. 5, No. 3 / OPTICS LETTERS 117 Disk-shaped heat-pipe oven used for lithium excited success- fully operated using both sodium and lithium as the working fluid. The lithium 4s 2 S 112 and 5s whosepressure is easily measured externally, the heat-pipe oven isolates the often corrosive vapor from windows

  5. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  6. MESOSCALE CONVECTIVE SYSTEMS Robert A. Houze Jr.

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    MESOSCALE CONVECTIVE SYSTEMS Robert A. Houze Jr. Department of Atmospheric Sciences University; published 31 December 2004. [1] Mesoscale convective systems (MCSs) have regions of both convective and stratiform precipitation, and they develop mesoscale circulations as they mature. The upward motion takes

  7. Abstract--The paper reviews solutions being explored to face the supply problems faced in the Chilean electricity market oven

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Católica de Chile)

    and transportation of natural gas. Private investors were strongly behind the process, and invested heavily in the Chilean electricity market oven recent years, given unexpected restrictions in natural gas transfers from Argentina. Investment in generation came to a stall, given uncertainties in natural gas supply and the risk

  8. Grass roots technology and energy policy: Solar ovens and wind turbines in Kenya

    SciTech Connect (OSTI)

    Kammen, D.M. [Harvard Univ., Cambridge, MA (United States). Dept. of Physics

    1992-12-31T23:59:59.000Z

    Kenya is said to be an ideal site for projects that promote renewable energy sources since it devotes over forty percent of its GNP to the purchase of imported coal and oil. The author presents a chronology of solar oven projects in Kenya and suggests that success of the program will be measured by the number of people who move on to wind turbine use. He discusses the role of renewable energy technology in reducing greenhouse gases and closes by recommending that industrialized nations that produce large amounts of carbon dioxide provide aid to develop projects that reduce carbon dioxide elsewhere in the world. At the same time they would receive credit towards their carbon dioxide quotas.

  9. Summing up of discussion on improvement trends in coke-oven gas purification flowsheets

    SciTech Connect (OSTI)

    Zemblevskii, K.K.

    1983-01-01T23:59:59.000Z

    Reference is made to a previously published article that included flowsheets for purification of coke-oven gas. It is concluded that the flowsheets for a process using arsenic-soda and vacuum-carbonate methods of sulfur removal in which the gas is cooled to 303-308/sup 0/K are seriously in error. Schemes involving minor refrigeration, sulfur removal by the circulating ammonia method and ammonia recovery as ammonia liquor are seen as promising but in need of further improvement. One scheme discussed (the VUKhIN scheme) involves ammonia recovery by the circulating phosphate method and sulfur removal by the circulating ammonia method is seen as a replacement for the minor refrigeration method. Since liquid ammonia consumption in agriculture is continually increasing, schemes that result in production of liquid ammonia rather than ammonia liquor should be seriously considered.

  10. Method of recovering sulfur from the hydrogen sulfide contained in coke oven gases

    SciTech Connect (OSTI)

    Laufhutte, D.

    1985-04-30T23:59:59.000Z

    Ammonia and hydrogen sulfide are washed out of the coke oven gas and stripped from the wash liquor in the form of gases and fumes or vapors. The ammonia is decomposed in a nickel catalyzer and a small part of the decomposition gases is supplied directly to a combustion furnace, while the larger part of the combustion gases is first cooled and freed from condensate, and only then supplied to the combustion furnace. In the combustion furnace, the proportion of H/sub 2/S/SO/sub 2/ needed for the Claus process is adjusted by a partial combustion of the decomposition gases. The gases from the combustion furnace are then processed in the Claus plant to sulfur.

  11. A mathematical model for the estimation of flue temperature in a coke oven

    SciTech Connect (OSTI)

    Choi, K.I.; Kim, S.Y.; Suo, J.S.; Hur, N.S.; Kang, I.S.; Lee, W.J.

    1997-12-31T23:59:59.000Z

    The coke plants at the Kwangyang works has adopted an Automatic Battery Control (ABC) system which consists of four main parts, battery heating control, underfiring heat and waste gas oxygen control, pushing and charging schedule and Autotherm-S that measures heating wall temperature during pushing. The measured heating wall temperature is used for calculating Mean Battery Temperature (MBT) which is average temperature of flues for a battery, but the Autotherm-S system can not provide the flue temperatures of an oven. This work attempted to develop mathematical models for the estimation of the flue temperature using the measured heating wall temperature and to examine fitness of the mathematical model for the coke plant operation by analysis of raw gas temperature at the stand pipe. Through this work it is possible to reflect heating wall temperature in calculating MBT for battery heating control without the interruption caused by a maintenance break.

  12. NATURAL CONVECTION IN ROOM GEOMETRIES

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, Fred; Kammerud, R.; Ruberg, K.

    1980-06-01T23:59:59.000Z

    Computer programs have been developed to numerically simulate natural convection in room geometries in two and three dimensions. The programs have been validated using published data from the literature, results from a full-scale experiment performed at Massachusetts Institute of Technology, and results from a small-scale experiment reported here. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single thermal zone in a direct-gain passive solar building. The results indicate that the building heating loads calculated by standard building energy analysis methods may be in error by as much as 50% as a result of their use of common assumptions regarding the convection processes which occur in an enclosure. It is also found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface.

  13. A transilient matrix for moist convection

    SciTech Connect (OSTI)

    Romps, D.; Kuang, Z.

    2011-08-15T23:59:59.000Z

    A method is introduced for diagnosing a transilient matrix for moist convection. This transilient matrix quantifies the nonlocal transport of air by convective eddies: for every height z, it gives the distribution of starting heights z{prime} for the eddies that arrive at z. In a cloud-resolving simulation of deep convection, the transilient matrix shows that two-thirds of the subcloud air convecting into the free troposphere originates from within 100 m of the surface. This finding clarifies which initial height to use when calculating convective available potential energy from soundings of the tropical troposphere.

  14. Seismic Constraints on Interior Solar Convection

    E-Print Network [OSTI]

    Hanasoge, S M; DeRosa, M L

    2010-01-01T23:59:59.000Z

    We constrain the velocity spectral distribution of global-scale solar convective cells at depth using techniques of local helioseismology. We calibrate the sensitivity of helioseismic waves to large-scale convective cells in the interior by analyzing simulations of waves propagating through a velocity snapshot of global solar convection via methods of time-distance helioseismology. Applying identical analysis techniques to observations of the Sun, we are able to bound from above the magnitudes of solar convective cells as a function of spatial convective scale. We find that convection at a depth of $r/R_\\odot = 0.95$ with spatial extent $\\ell <20$, where $\\ell$ is the spherical harmonic degree, comprise weak flow systems, on the order of 15 m/s or less. Convective features deeper than $r/R_\\odot = 0.95$ are more difficult to image due to the rapidly decreasing sensitivity of helioseismic waves.

  15. The sensitivity of tropical convective precipitation to the direct radiative forcings of black carbon aerosols emitted from major regions

    E-Print Network [OSTI]

    Wang, Chien

    Previous works have suggested that the direct radiative forcing (DRF) of black carbon (BC) aerosols are able to force a significant change in tropical convective precipitation ranging from the Pacific and Indian Ocean to ...

  16. Innovative coke oven gas cleaning system for retrofit applications. Environmental Monitoring program. Volume 1 - sampling progrom report. Baseline Sampling Program report

    SciTech Connect (OSTI)

    Stuart, L.M.

    1994-05-27T23:59:59.000Z

    Bethlehem Steel Corporation (BSC), in conjunction with the Department of Energy (DOE) is conducting a Clean Coal Technology (CCT) project at its Sparrows Point, Maryland Coke Oven Plant. This innovative coke oven gas cleaning system combines several existing technologies into an integrated system for removing impurities from Coke Oven Gas (COG) to make it an acceptable fuel. DOE provided cost-sharing under a Cooperative Agreement with BSC. This Cooperative Agreement requires BSC to develop and conduct and Environmental Monitoring Plan for the Clean Coal Technology project and to report the status of the EMP on a quarterly basis. It also requires the preparation of a final report on the results of the Baseline Compliance and Supplemental Sampling Programs that are part of the EMP and which were conducted prior to the startup of the innovative coke oven gas cleaning system. This report is the Baseline Sampling Program report.

  17. SOLOX coke-oven gas desulfurization ppm levels -- No toxic waste

    SciTech Connect (OSTI)

    Platts, M. (Thyssen Still Otto Technical Services, Pittsburgh, PA (United States)); Tippmer, K. (Thyssen Still Otto Anlagentechnik GmbH, Bochum (Germany))

    1994-09-01T23:59:59.000Z

    For sulfur removal from coke-oven gas, the reduction/oxidation processes such as Stretford are the most effective, capable of removing the H[sub 2]S down to ppm levels. However, these processes have, in the past, suffered from ecological problems with secondary pollutant formation resulting from side reactions with HCN and O[sub 2]. The SOLOX gas desulfurization system is a development of the Stretford process in which the toxic effluent problems are eliminated by installing a salt decomposition process operating according to the liquid-phase hydrolysis principle. In this process, the gaseous hydrolysis products H[sub 2]S, NH[sub 3] and CO[sub 2] are returned to the untreated gas, and the regenerated solution is recycled to the absorption process. The blowdown from the absorption circuit is fed into a tube reactor where the hydrolysis process takes place. The toxic salts react with water, producing as reaction products the gases H[sub 2]S, NH[sub 3] and CO[sub 2], and the nontoxic salt Na[sub 2]SO[sub 4]. From the hydrolysis reactor the liquid stream flows into a fractionating crystallization plant. This plant produces a recycle stream of regenerated absorption solution and a second stream containing most of the Na[sub 2]SO[sub 4]. This second stream comprises the net plant waste and can be disposed of with the excess ammonia liquor or sprayed onto the coal.

  18. Mesoscale convective complex vs. non-mesoscale convective complex thunderstorms: a comparison of selected meteorological variables

    E-Print Network [OSTI]

    Hoofard, Michael Eugene

    1986-01-01T23:59:59.000Z

    MESOSCALE CONVECTIVE CCMPLLX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis MICHAkL EUGENE JJOOFARD Submitted to the Graduate College of Texas AJkM University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1986 Major Subj ect: Meteorology MESOSCALE CONVECTIVE COMPLEX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis...

  19. Experience and results of new heating control system of coke oven batteries at Rautaruukki Oy Raahe Steel

    SciTech Connect (OSTI)

    Swanljung, J.; Palmu, P. [Rautaruukki Oy Raahe Steel (Finland)

    1997-12-31T23:59:59.000Z

    The latest development and results of the heating control system at Raahe Steel are presented in this paper. From the beginning of coke production in Rautaruukki Oy Raahe Steel (October 1987) the heating control systems have been developed. During the first stage of development work at the coking plant (from year 1987 to 1992), when only the first coke oven battery consisting of 35 ovens was in production, the main progress was in the field of process monitoring. After commissioning of the second stage of the coking plant (November 1992), the development of the new heating control model was started. Target of the project was to develop a dynamic control system which guides the heating of batteries through the various process conditions. Development work took three years and the heating control system was commissioned in the year 1995. Principle of the second generation system is an energy balance calculation, coke end temperature determination and dynamic oven scheduling system. The control is based on simultaneous feedforward and feedback control. The fuzzy logic components were added after about one year experience.

  20. Energy transport using natural convection boundary layers

    SciTech Connect (OSTI)

    Anderson, R.

    1986-04-01T23:59:59.000Z

    Natural convection is one of the major modes of energy transport in passive solar buildings. There are two primary mechanisms for natural convection heat transport through an aperture between building zones: (1) bulk density differences created by temperature differences between zones; and (2) thermosyphon pumping created by natural convection boundary layers. The primary objective of the present study is to compare the characteristics of bulk density driven and boundary layer driven flow, and discuss some of the advantages associated with the use of natural convection boundary layers to transport energy in solar building applications.

  1. Influence of geometry on natural convection in buildings

    SciTech Connect (OSTI)

    White, M.D.; Winn, C.B.; Jones, G.F.; Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    Strong free convection airflows occur within passive solar buildings resulting from elevated temperatures of surfaces irradiated by solar energy compared with the cooler surfaces not receiving radiation. The geometry of a building has a large influence on the directions and magnitudes of natural airflows, and thus heat transfer between zones. This investigation has utilized a variety of reduced-scale building configurations to study the effects of geometry on natural convection heat transfer. Similarity between the reduced-scale model and a full-scale passive solar building is achieved by having similar geometries and by replacing air with Freon-12 gas as the model's working fluid. Filling the model with Freon-12 gas results in similarity in Prandtl numbers and Rayleigh numbers based on temperature differences in the range from 10/sup 9/ to 10/sup 11/. Results from four geometries are described with an emphasis placed on the effects of heat loss on zone temperature stratification shifts.

  2. Factors affecting the eversion of sorghum grain using microwave energy in the 2450-mc range

    E-Print Network [OSTI]

    Beerwinkle, Kenneth Ray

    1967-01-01T23:59:59.000Z

    for the degree of NASTER OF SCIENCE AUGUST 1967 Hajor Subject: Agricultural Engineering FACTORS AFFECTING THE EVERSION OF SORGHUM GRAIN USING MICROWAVE ENERGY IN THE 2450-MC RANGE A Thesis By KENNETH RAY BEERWINKCE Approved as to style and content by... OF FIGURES Figure Page Phasor Representation of Total Current, I, Trans- vezsing a Condenser. Parallel Equivalent Circuit of a Dielectric in a Condenser. Laboratory Microwave Test Equipment. A. Oven Appli- cator. B. Wave Guide. C. Directional Po. . er...

  3. NISTIR 6095 Horizontal Convective Condensation of

    E-Print Network [OSTI]

    Oak Ridge National Laboratory

    NISTIR 6095 Horizontal Convective Condensation of Alternative Refrigerants within a Micro-Fin Tube Horizontal Convective Condensation of Alternative Refrigerants Within a Micro-Fin Tube Mark A. Kedzierski J for flow boiling pressure drop in a smooth tube. Correlation of the pressure drop measurements suggested

  4. Collective phase description of oscillatory convection

    SciTech Connect (OSTI)

    Kawamura, Yoji, E-mail: ykawamura@jamstec.go.jp [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan)] [Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan); Nakao, Hiroya [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)] [Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, Tokyo 152-8552 (Japan)

    2013-12-15T23:59:59.000Z

    We formulate a theory for the collective phase description of oscillatory convection in Hele-Shaw cells. It enables us to describe the dynamics of the oscillatory convection by a single degree of freedom which we call the collective phase. The theory can be considered as a phase reduction method for limit-cycle solutions in infinite-dimensional dynamical systems, namely, stable time-periodic solutions to partial differential equations, representing the oscillatory convection. We derive the phase sensitivity function, which quantifies the phase response of the oscillatory convection to weak perturbations applied at each spatial point, and analyze the phase synchronization between two weakly coupled Hele-Shaw cells exhibiting oscillatory convection on the basis of the derived phase equations.

  5. Development and introduction of methods for extracting hydrogen sulfide and hydrogen cyanide from coke-oven gas

    SciTech Connect (OSTI)

    Litvinenko, M.S.; Zaichenko, V.M.

    1980-01-01T23:59:59.000Z

    The progress between 1933 and the present in desulfurizing coal gas from coke ovens and making use of the by-products to produce sulfuric acid, thioyanates, etc. is described. The vacuum carbonate process and the monoethanolamine method are apparently now preferred, but some plants are still using modified arsenic-soda processes. More recently additional by-products have been thiocyanates (for producing acrylonitrile fiber) and hydrogen xanthanates. The production of other organic sulfur and cyanide compounds has been investigated for use as herbicides, corrosion inhibitors, etc. (LTN)

  6. Innovative coke oven gas cleaning system for retrofit applications. Quarterly environmental monitoring report No. 1, January 1, 1991--June 30, 1991

    SciTech Connect (OSTI)

    Not Available

    1992-08-24T23:59:59.000Z

    The coke plant at the Sparrows Point Plant consist of three coke oven batteries and two coal chemical plants. The by-product coke oven gas (COG) consists primarily of hydrogen, methane, carbon monoxide, nitrogen and contaminants consisting of tars, light oils (benzene, toluene, and xylene) hydrogen sulfide, ammonia, water vapor and other hydrocarbons. This raw coke oven gas needs to be cleaned of most of its contaminants before it can be used as a fuel at other operations at the Sparrows Point Plant. In response to environmental concerns, BSC decided to replace much of the existing coke oven gas treatment facilities in the two coal chemical Plants (A and B) with a group of technologies consisting of: Secondary Cooling of the Coke oven Gas; Hydrogen Sulfide Removal; Ammonia Removal; Deacification of Acid Gases Removed; Ammonia Distillation and Destruction; and, Sulfur Recovery. This combination of technologies will replace the existing ammonia removal system, the final coolers, hydrogen sulfide removal system and the sulfur recovery system. The existing wastewater treatment, tar recovery and one of the three light oil recovery systems will continue to be used to support the new innovative combination of COG treatment technologies.

  7. Convective Cooling and Passive Stack Improvements in Motors (Presentation)

    SciTech Connect (OSTI)

    Bennion, K.

    2014-06-01T23:59:59.000Z

    This presentation discusses current research at NREL in convective cooling and passive stack improvements in motors.

  8. Structure and evolution of a convective band MCS

    E-Print Network [OSTI]

    Valdes-Manzanilla, Arturo

    1995-01-01T23:59:59.000Z

    circulation of the Mesoscale Convective Complex apparently aided in the formation of new lines of convection behind the primary convective line of the system. This process was repeated twice in the storm life cycle and led to multiple bands of convection...

  9. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-01-01T23:59:59.000Z

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  10. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-11-01T23:59:59.000Z

    Natural convection between spaces in a building which play a major role in energy transfer are discussed. Two situations are investigated: Convection through a single doorway into a remote room, and a convective loop in a two story house with a south sunspace where a north stairway serves as the return path. A doorway sizing equation is given for the single door case. Data from airflow monitoring in one two-story house and summary data for five others are presented. The nature of the airflow and design guidelines are presented.

  11. Circulation and convection in the Irminger Sea

    E-Print Network [OSTI]

    Våge, Kjetil

    2010-01-01T23:59:59.000Z

    Aspects of the circulation and convection in the Irminger Sea are investigated using a variety of in-situ, satellite, and atmospheric reanalysis products. Westerly Greenland tip jet events are intense, small-scale wind ...

  12. Modeling convection in the Greenland Sea

    E-Print Network [OSTI]

    Bhushan, Vikas

    1998-01-01T23:59:59.000Z

    A detailed examination of the development of a deep convection event observed in the Greenland Sea in 1988-89 is carried out through a combination of modeling, scale estimates, and data analysis. We develop a prognostic ...

  13. Stochastic and mesoscopic models for tropical convection

    E-Print Network [OSTI]

    Majda, Andrew J.

    Courant Institute of Mathematical Sciences and Center for Atmosphere and Ocean Sciences, New York penetrative convection to heights of 5­10 km with associated anvil towers of clouds. Observational data

  14. Marangoni convection in droplets on superhydrophobic surfaces

    E-Print Network [OSTI]

    Tam, Daniel

    We consider a small droplet of water sitting on top of a heated superhydrophobic surface. A toroidal convection pattern develops in which fluid is observed to rise along the surface of the spherical droplet and to accelerate ...

  15. Origins of convective activity over Panama

    E-Print Network [OSTI]

    Strager, Christopher Stephen

    1989-01-01T23:59:59.000Z

    ORIGINS OF CONVECTIVE ACTIVITY OVER PANAMA A Thesis by CHRISTOPHER STEPHEN STRAGER Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1989... Major Subject: Meteorology ORIGINS OF CONVECTIVE ACTIVITY OVER PANAMA A Thesis by CHRISTOPHER STEPHEN STRAGER Approved as to style and content by: Steven W. ons (Chair of Committee) Kenneth C. Brundidge (Member) Rud lf J. Freund ( ember...

  16. Convective cores in galactic cooling flows

    E-Print Network [OSTI]

    A. Kritsuk; T. Plewa; E. Mueller

    2001-05-02T23:59:59.000Z

    We use hydrodynamic simulations with adaptive grid refinement to study the dependence of hot gas flows in X-ray luminous giant elliptical galaxies on the efficiency of heat supply to the gas. We consider a number of potential heating mechanisms including Type Ia supernovae and sporadic nuclear activity of a central supermassive black hole. As a starting point for this research we use an equilibrium hydrostatic recycling model (Kritsuk 1996). We show that a compact cooling inflow develops, if the heating is slightly insufficient to counterbalance radiative cooling of the hot gas in the central few kiloparsecs. An excessive heating in the centre, instead, drives a convectively unstable outflow. We model the onset of the instability and a quasi-steady convective regime in the core of the galaxy in two-dimensions assuming axial symmetry. Provided the power of net energy supply in the core is not too high, the convection remains subsonic. The convective pattern is dominated by buoyancy driven large-scale mushroom-like structures. Unlike in the case of a cooling inflow, the X-ray surface brightness of an (on average) isentropic convective core does not display a sharp maximum at the centre. A hybrid model, which combines a subsonic peripheral cooling inflow with an inner convective core, appears to be stable. We also discuss observational implications of these results.

  17. Simulated diurnal rainfall physics in a multi-scale global climate model with embedded explicit convection

    E-Print Network [OSTI]

    Pritchard, Michael Stephen

    2011-01-01T23:59:59.000Z

    2.8: Relationship among mesoscale convective complex (MCC)C. J. Anderson, 2008: Idealized mesoscale convective system205. Houze, R. , 2004: Mesoscale convective systems. Reviews

  18. "Diffusion of Innovation: Solar Oven Use in Lesotho (Africa)." Grundy, William and Roy Grundy. Advances in Solar Cooking: Proceedings of the 2nd International Conference on Solar Cooker Use and Technology. Shyam S. Nandwani, ed. July 12-15, 1994.

    E-Print Network [OSTI]

    Noble, William Stafford

    "Diffusion of Innovation: Solar Oven Use in Lesotho (Africa)." Grundy, William and Roy Grundy. Advances in Solar Cooking: Proceedings of the 2nd International Conference on Solar Cooker Use and Technology. Shyam S. Nandwani, ed. July 12-15, 1994. pp. 240-247. 1 DIFFUSION OF INNOVATION: SOLAR OVEN USE

  19. Equatorial symmetry of Boussinesq convective solutions in a rotating spherical shell allowing rotation of the inner and outer spheres

    SciTech Connect (OSTI)

    Kimura, Keiji; Takehiro, Shin-ichi; Yamada, Michio [Research Institute for Mathematical Sciences, Kyoto University, Kyoto 606-8502 (Japan)

    2014-08-15T23:59:59.000Z

    We investigate properties of convective solutions of the Boussinesq thermal convection in a moderately rotating spherical shell allowing the respective rotation of the inner and outer spheres due to the viscous torque of the fluid. The ratio of the inner and outer radii of the spheres, the Prandtl number, and the Taylor number are fixed to 0.4, 1, and 500{sup 2}, respectively. The Rayleigh number is varied from 2.6 × 10{sup 4} to 3.4 × 10{sup 4}. In this parameter range, the behaviours of obtained asymptotic convective solutions are almost similar to those in the system whose inner and outer spheres are restricted to rotate with the same constant angular velocity, although the difference is found in the transition process to chaotic solutions. The convective solution changes from an equatorially symmetric quasi-periodic one to an equatorially symmetric chaotic one, and further to an equatorially asymmetric chaotic one, as the Rayleigh number is increased. This is in contrast to the transition in the system whose inner and outer spheres are assumed to rotate with the same constant angular velocity, where the convective solution changes from an equatorially symmetric quasi-periodic one, to an equatorially asymmetric quasi-periodic one, and to equatorially asymmetric chaotic one. The inner sphere rotates in the retrograde direction on average in the parameter range; however, it sometimes undergoes the prograde rotation when the convective solution becomes chaotic.

  20. Influence of technological factors on statics of hydrogen sulfide absorption from coke-oven gas by the ammonia process

    SciTech Connect (OSTI)

    Nazarov, V.G.; Kamennykh, B.M.; Rus'yanov, N.D.

    1983-01-01T23:59:59.000Z

    The basic technological factors that determine the effectiveness of hydrogen sulfide absorption from coke-oven gas by the cyclic ammonia process are the initial H/sub 2/S content of the gas, the degree of purification, the absorption temperature and the NH/sub 3/ and CO/sub 2/ contents of the absorbent solution. The effects of these factors on the statics of hydrogen sulfide absorption are studied. The investigation is based on the phase-equilibrium distributions of components in the absorption-desorption gas-cleaning cycle. The mathematical model is presented which includes the solution of a system of chemical equilibrium equations for reactions in the solution, material balances, and electrical neutrality. 4 references, 5 figures, 1 table.

  1. Asteroseismic Diagnostics of Stellar Convective Cores

    E-Print Network [OSTI]

    Anwesh Mazumdar; Sarbani Basu; Braxton L. Collier; Pierre Demarque

    2006-08-16T23:59:59.000Z

    We present a detailed study of the small frequency separations as diagnostics of the mass of the convective core and evolutionary stage of solar-type stars. We demonstrate how the small separations can be combined to provide sensitive tests for the presence of convective overshoot at the edge of the core. These studies are focused on low degree oscillation modes, the only modes expected to be detected in distant stars. Using simulated data with realistic errors, we find that the mass of the convective core can be estimated to within 5% if the total stellar mass is known. Systematic errors arising due to uncertainty in the mass could be up to 20%. The evolutionary stage of the star, determined in terms of the central hydrogen abundance using our proposed technique, however, is much less sensitive to the mass estimate.

  2. A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS WITH

    E-Print Network [OSTI]

    A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS WITH ATTACHED WALL JETS By WEIXIU KONGQuest Information and Learning Company. #12;II A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS

  3. LARGE EDDY SIMULATION OF NATURAL AND MIXED CONVECTION AIRFLOW INDOORS

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    coordinate Greek symbols : Thermal expansion coefficient t : Time step : Filter size : Kinematic viscocity convection, such as winter heating by a baseboard heater; forced convection, such as free cooling in shoulder

  4. The Ratio of Helium- to Hydrogen-Atmosphere White Dwarfs: Direct Evidence for Convective Mixing

    E-Print Network [OSTI]

    P. -E. Tremblay; P. Bergeron

    2007-10-04T23:59:59.000Z

    We determine the ratio of helium- to hydrogen-atmosphere white dwarf stars as a function of effective temperature from a model atmosphere analysis of the infrared photometric data from the Two Micron All Sky Survey combined with available visual magnitudes. Our study surpasses any previous analysis of this kind both in terms of the accuracy of the Teff determinations as well as the size of the sample. We observe that the ratio of helium- to hydrogen-atmosphere white dwarfs increases gradually from a constant value of ~0.25 between Teff = 15,000 K and 10,000 K to a value twice as large in the range 10,000 > Teff > 8000 K, suggesting that convective mixing, which occurs when the bottom of the hydrogen convection zone reaches the underlying convective helium envelope, is responsible for this gradual transition. The comparison of our results with an approximate model used to describe the outcome of this convective mixing process implies hydrogen mass layers in the range log M_H/M_tot = -10 to -8 for about 15% of the DA stars that survived the DA to DB transition near Teff ~ 30,000 K, the remainder having presumably more massive layers above log M_H/M_tot ~ -6.

  5. Fluidized bed boiler convective zone tube replacement

    SciTech Connect (OSTI)

    Not Available

    1991-03-21T23:59:59.000Z

    A major problem with the Georgetown University Atomspheric-Pressure, Fluidized-Bed Combustor-Boiler (GU AFBC) experienced during the first six years of operation was tube erosion. Previous corrective measures for in-bed tube erosion appeared to be effective, but excessive wear of the convective zone tubes was still occurring, and the entire heat transfer tube bundle in the boiler required replacement. In the planned project,the eroded tubes would be replaced, and the convective zone modified to eliminate the problem. Progress is discussed.

  6. Convection and dynamo action in B stars

    E-Print Network [OSTI]

    Augustson, Kyle C; Toomre, Juri

    2010-01-01T23:59:59.000Z

    Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to model turbulent dynamics within a 10 solar mass main-sequence (MS) B-type star rotating at 4 times the solar rate. We find that strong (900 kG) magnetic fields arise within the turbulence of the core and penetrate into the stably stratified radiative zone. These fields exhibit complex, time-dependent behavior including reversals in magnetic polarity and shifts between which hemisphere dominates the total magnetic energy.

  7. Convection and convective overshooting in stars more massive than 10 $M_\\odot$

    E-Print Network [OSTI]

    Jie, Jin; Lv, Guoliang

    2015-01-01T23:59:59.000Z

    In this paper, four sets of evolutionary models are computed with different values of the mixing length parameter $\\alpha_{\\rm p}$ and the overshooting parameter $\\delta_{\\rm ov}$. The properties of the convective cores and the convective envelopes are studied in the massive stars. We get three conclusions: First, the larger $\\alpha_{\\rm p}$ leads to enhancing the convective mixing, removing the chemical gradient, and increasing the convective heat transfer efficiency. Second, core potential $\\phi_{\\rm c} = M_{\\rm c} / R_{\\rm c}$ describes sufficiently the evolution of a star, whether it is a red or blue supergiant at central helium ignition. Third, the discontinuity of hydrogen profile above the hydrogen burning shell seriously affect the occurrence of blue loops in the Hertzsprung--Russell diagram.

  8. Solar Dynamics, Rotation, Convection and Overshoot

    E-Print Network [OSTI]

    Hanasoge, S; Roth, M; Schou, J; Schuessler, M; Thompson, M J

    2015-01-01T23:59:59.000Z

    We discuss recent observational, theoretical and modeling progress made in understanding the Sun's internal dynamics, including its rotation, meridional flow, convection and overshoot. Over the past few decades, substantial theoretical and observational effort has gone into appreciating these aspects of solar dynamics. A review of these observations, related helioseismic methodology and inference and computational results in relation to these problems is undertaken here.

  9. The effect of convection on pulsational stability

    E-Print Network [OSTI]

    G. Houdek

    2008-10-29T23:59:59.000Z

    A review on the current state of mode physics in classical pulsators is presented. Two, currently in use, time-dependent convection models are compared and their applications on mode stability are discussed with particular emphasis on the location of the Delta Scuti instability strip.

  10. Convective Instability of a Boundary Layer with

    E-Print Network [OSTI]

    Conrad, Clint

    proportional to the integral over the depth of the lithosphere of the 19 #12;ratio of thermal buoyancy. Such instabilities are driven by the negative thermal buoyancy of the cold lithosphere and retarded largely for driving convective downwelling. For non-Newtonian viscosity with power law exponent n and temperature

  11. Convective and absolute instabilities in eccentric Taylor

    E-Print Network [OSTI]

    Shyamasundar, R.K.

    Convective and absolute instabilities in eccentric Taylor Laboratoire de mécanique des fluides et d and absolute instabilities in Taylor-Couette-Poiseuille flow Benoît PIER Laboratoire de mécanique des fluides flow type often disrupt oil-well drilling By implementing a detailed instability analysis, the dynamics

  12. CONVECTION THEORY AND SUB-PHOTOSPHERIC STRATIFICATION

    SciTech Connect (OSTI)

    Arnett, David; Meakin, Casey; Young, Patrick A., E-mail: darnett@as.arizona.ed, E-mail: casey.meakin@gmail.co, E-mail: patrick.young.1@asu.ed [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2010-02-20T23:59:59.000Z

    As a preliminary step toward a complete theoretical integration of three-dimensional compressible hydrodynamic simulations into stellar evolution, convection at the surface and sub-surface layers of the Sun is re-examined, from a restricted point of view, in the language of mixing-length theory (MLT). Requiring that MLT use a hydrodynamically realistic dissipation length gives a new constraint on solar models. While the stellar structure which results is similar to that obtained by Yale Rotational Evolution Code (Guenther et al.; Bahcall and Pinsonneault) and Garching models (Schlattl et al.), the theoretical picture differs. A new quantitative connection is made between macro-turbulence, micro-turbulence, and the convective velocity scale at the photosphere, which has finite values. The 'geometric parameter' in MLT is found to correspond more reasonably with the thickness of the superadiabatic region (SAR), as it must for consistency in MLT, and its integrated effect may correspond to that of the strong downward plumes which drive convection (Stein and Nordlund), and thus has a physical interpretation even in MLT. If we crudely require the thickness of the SAR to be consistent with the 'geometric factor' used in MLT, there is no longer a free parameter, at least in principle. Use of three-dimensional simulations of both adiabatic convection and stellar atmospheres will allow the determination of the dissipation length and the geometric parameter (i.e., the entropy jump) more realistically, and with no astronomical calibration. A physically realistic treatment of convection in stellar evolution will require substantial additional modifications beyond MLT, including nonlocal effects of kinetic energy flux, entrainment (the most dramatic difference from MLT found by Meakin and Arnett), rotation, and magnetic fields.

  13. Wind reversals in turbulent Rayleigh-Benard convection

    E-Print Network [OSTI]

    Francisco Fontenele Araujo; S. Grossmann; D. Lohse

    2005-08-29T23:59:59.000Z

    The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \\leq \\Pr \\leq 10^{3}$ and $10^{7} \\leq \\Ra \\leq 10^{12}$, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as $\\Re_{rms} \\sim \\Ra^{[0.41 ... 0.47]}$ (depending on Pr), and as $\\Re_{rms} \\sim \\Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law $\\omega / (\

  14. Scaling of convective velocity in a vertically vibrated granular bed

    E-Print Network [OSTI]

    Tomoya M. Yamada; Hiroaki Katsuragi

    2014-05-30T23:59:59.000Z

    We experimentally study the velocity scaling of granular convection which is a possible mechanism of the regolith migration on the surface of small asteroids. In order to evaluate the contribution of granular convection to the regolith migration, the velocity of granular convection under the microgravity condition has to be revealed. Although it is hard to control the gravitational acceleration in laboratory experiments, scaling relations involving the gravitational effect can be evaluated by systematic experiments. Therefore, we perform such a systematic experiment of the vibration-induced granular convection. From the experimental data, a scaling form for the granular convective velocity is obtained. The obtained scaling form implies that the granular convective velocity can be decomposed into two characteristic velocity components: vibrational and gravitational velocities. In addition, the system size dependence is also scaled. According to the scaling form, the granular convective velocity $v$ depends on the gravitational acceleration $g$ as $v \\propto g^{0.97}$ when the normalized vibrational acceleration is fixed.

  15. Convection in nanofluids with a particle-concentration-dependent thermal conductivity

    E-Print Network [OSTI]

    Glässl, Martin; Zimmermann, Walter

    2010-01-01T23:59:59.000Z

    Thermal convection in nanofluids is investigated by means of a continuum model for binary-fluid mixtures, with a thermal conductivity depending on the local concentration of colloidal particles. The applied temperature difference between the upper and the lower boundary leads via the Soret effect to a variation of the colloid concentration and therefore to a spatially varying heat conductivity. An increasing difference between the heat conductivity of the mixture near the colder and the warmer boundary results in a shift of the onset of convection to higher values of the Rayleigh number for positive values of the separation ratio $\\psi>0$ and to smaller values in the range $\\psi0$. This range can be extended by increasing the difference in the thermal conductivity and it is bounded by two codimension-2 bifurcations.

  16. Convection in nanofluids with a particle-concentration-dependent thermal conductivity

    E-Print Network [OSTI]

    Martin Glässl; Markus Hilt; Walter Zimmermann

    2011-03-09T23:59:59.000Z

    Thermal convection in nanofluids is investigated by means of a continuum model for binary-fluid mixtures, with a thermal conductivity depending on the local concentration of colloidal particles. The applied temperature difference between the upper and the lower boundary leads via the Soret effect to a variation of the colloid concentration and therefore to a spatially varying heat conductivity. An increasing difference between the heat conductivity of the mixture near the colder and the warmer boundary results in a shift of the onset of convection to higher values of the Rayleigh number for positive values of the separation ratio psi>0 and to smaller values in the range psi0. This range can be extended by increasing the difference in the thermal conductivity and it is bounded by two codimension-2 bifurcations.

  17. Magneto-convective models of red dwarfs: constraints imposed by the lithium abundance

    E-Print Network [OSTI]

    MacDonald, J

    2015-01-01T23:59:59.000Z

    Magnetic fields impede the onset of convection, thereby altering the thermal structure of a convective envelope in a low mass star: this has an effect on the amount of lithium depletion in a magnetized star. In order to quantify this effect, we have applied a magneto-convective model to two low mass stars for which lithium abundances and precise structural parameters are known: YY Gem and CU Cnc. For both stars, we have obtained models which satisfy empirical constraints on the following parameters: R, L, surface magnetic field strength, and Li abundance. In the case of YY Gem, we have obtained a model which satisfies the empirical constraints with an internal magnetic field of several megagauss: such a field strength is within the range of a dynamo where the field energy is in equipartition with rotational energy deep inside the convection zone. However, in the case of CU Cnc, the Li requires an internal magnetic field which is probably too strong for a dynamo origin: we suggest possible alternatives which m...

  18. Coke oven air and water pollution. 1970-June, 1981 (citations from the Engineering Index Data Base). Report for 1970-Jun 81

    SciTech Connect (OSTI)

    Not Available

    1981-07-01T23:59:59.000Z

    Monitoring, sampling, analyzing, transport properties, and control of emissions and effluents are cited in this compilation from worldwide journals. Pollutants described are sulfur dioxide, hydrogen sulfide, ammonia, phenols, benzopyrene, particulates and other trace elements and compounds. Process and equipment modifications, such as pipeline charging, wet and dry quenching, retrofitting, and oven leakage preventives are included. (This updated bibliography contains 210 citations, 9 of which are new entries to the previous edition.)

  19. Urinary 1-hydroxypyrene concentrations in Chinese coke oven workers relative to job category, respirator usage, and cigarette smoking

    SciTech Connect (OSTI)

    Bo Chen; Yunping Hu; Lixing Zheng; Qiangyi Wang; Yuanfen Zhou; Taiyi Jin [Fudan University, Shanghai (China). School of Public Health

    2007-09-15T23:59:59.000Z

    1-Hydroxypyrene (1-OHP) is a biomarker of recent exposure to polycyclic aromatic hydrocarbons (PAHs). We investigated whether urinary 1-OHP concentrations in Chinese coke oven workers (COWs) are modulated by job category, respirator usage, and cigarette smoking. The present cross-sectional study measured urinary 1-OHP concentrations in 197 COWs from Coking plant I and 250 COWs from Coking plant II, as well as 220 unexposed referents from Control plant I and 56 referents from Control plant II. Urinary 1-OHP concentrations (geometric mean, {mu}mol/mol creatinine) were 5.18 and 4.21 in workers from Coking plants I and II, respectively. The highest 1-OHP levels in urine were found among topside workers including lidmen, tar chasers, and whistlers. Benchmen had higher 1-OHP levels than other workers at the sideoven. Above 75% of the COWs exceeded the recommended occupational exposure limit of 2.3 {mu}mol/mol creatinine. Respirator usage and increased body mass index (BMI) slightly reduced 1-OHP levels in COWs. Cigarette smoking significantly increased urinary 1-OHP levels in unexposed referents but had no effect in COWs. Chinese COWs, especially topside workers and benchmen, are exposed to high levels of PAHs. Urinary 1-OHP concentrations appear to be modulated by respirator usage and BMI in COWs, as well as by smoking in unexposed referents.

  20. Innovative coke oven gas cleaning system for retrofit applications. Quarterly technical progress report No. 4, October 1, 1990 to December 31, 1990

    SciTech Connect (OSTI)

    Kwasnoski, D.

    1993-10-22T23:59:59.000Z

    Work on this coke oven gas cleaning demonstration project (CCT-II) this quarter has been focused on Phase IIB tasks, and include engineering, procurement, construction, and training. Additionally, plans for changes in the operating schedule of the coke plant that affect the demonstration project are described. Engineering efforts are nearly complete. Remaining to be finalized is an assessment of electrical heat tracing/insulation needs for pipe lines, assessment of fire protection requirements, and instrument modifications. Procurement of all major equipment items is complete, except for possible additions to fire fighting capabilities. Major focus is on expediting pipe and structural steel to the project site. Civil construction is complete except for minor pads and bases as required for pipe supports, etc. Erection of the hydrogen sulfide and ammonia scrubber vessels is complete. Installation of scrubber vessel internals is underway. A subcontractor has been retained to develop a computerized program for operations and maintenance training for the coke oven gas treatment plant. Recent developments in the coke plant operating plans will result in reductions in the rate of production of coke oven gas to be processed in the demonstration project.

  1. Laser induced natural convection and thermophoresis

    SciTech Connect (OSTI)

    Wang, C.Y.; Cipolla, J.; Morse, T.F.

    1983-07-01T23:59:59.000Z

    The influence of axial laser volumetric heating and forced convection on the motion of aerosol particles in a vertical tube has been studied. The asymptotic case of constant wall temperature provides simple temperature and velocity profiles that determine the convection and thermophoretic motion of small aerosol particles. For the case in which the flow (in the absence of laser heating) is downward, the laser heating induces upward buoyant motion near the tube center. When the laser heating is taken to be constant (a small absorption limit), a velocity profile may be found that will minimize the distance over which particles are deposited on the wall. Such an observation may have some bearing on the manufacture of preforms from which optical fibers are drawn.

  2. Convective Dynamo Simulation with a Grand Minimum

    E-Print Network [OSTI]

    Augustson, Kyle; Miesch, Mark; Toomre, Juri

    2015-01-01T23:59:59.000Z

    The global-scale dynamo action achieved in a simulation of a Sun-like star rotating at thrice the solar rate is assessed. The 3-D MHD Anelastic Spherical Harmonic (ASH) code, augmented with a viscosity minimization scheme, is employed to capture convection and dynamo processes in this G-type star. The simulation is carried out in a spherical shell that encompasses 3.8 density scale heights of the solar convection zone. It is found that dynamo action with a high degree of time variation occurs, with many periodic polarity reversals occurring roughly every 6.2 years. The magnetic energy also rises and falls with a regular period. The magnetic energy cycles arise from a Lorentz-force feedback on the differential rotation, whereas the processes leading to polarity reversals are more complex, appearing to arise from the interaction of convection with the mean toroidal fields. Moreover, an equatorial migration of toroidal field is found, which is linked to the changing differential rotation, and potentially to a no...

  3. Convective heat transport in geothermal systems

    SciTech Connect (OSTI)

    Lippmann, M.J.; Bodvarsson, G.S.

    1986-08-01T23:59:59.000Z

    Most geothermal systems under exploitation for direct use or electrical power production are of the hydrothermal type, where heat is transferred essentially by convection in the reservoir, conduction being secondary. In geothermal systems, buoyancy effects are generally important, but often the fluid and heat flow patterns are largely controlled by geologic features (e.g., faults, fractures, continuity of layers) and location of recharge and discharge zones. During exploitation, these flow patterns can drastically change in response to pressure and temperature declines, and changes in recharge/discharge patterns. Convective circulation models of several geothermal systems, before and after start of fluid production, are described, with emphasis on different characteristics of the systems and the effects of exploitation on their evolution. Convective heat transport in geothermal fields is discussed, taking into consideration (1) major geologic features; (2) temperature-dependent rock and fluid properties; (3) fracture- versus porous-medium characteristics; (4) single- versus two-phase reservoir systems; and (5) the presence of noncondensible gases.

  4. Magneto-convection in a sunspot umbra

    E-Print Network [OSTI]

    M. Schuessler; A. Voegler

    2006-03-03T23:59:59.000Z

    Results from a realistic simulation of 3D radiative magneto-convection in a strong background magnetic field corresponding to the conditions in sunspot umbrae are shown. The convective energy transport is dominated by narrow upflow plumes with adjacent downflows, which become almost field-free near the surface layers. The strong external magnetic field forces the plumes to assume a cusp-like shape in their top parts, where the upflowing plasma loses its buoyancy. The resulting bright features in intensity images correspond well (in terms of brightness, size, and lifetime) to the observed umbral dots in the central parts of sunspot umbrae. Most of the simulated umbral dots have a horizontally elongated form with a central dark lane. Above the cusp, most plumes show narrow upflow jets, which are driven by the pressure of the piled-up plasma below. The large velocities and low field strengths in the plumes are effectively screened from spectroscopic observation because the surfaces of equal optical depth are locally elevated, so that spectral lines are largely formed above the cusp. Our simulations demonstrate that nearly field-free upflow plumes and umbral dots are a natural result of convection in a strong, initially monolithic magnetic field.

  5. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 2, Fluorescent lamp ballasts, television sets, room air conditioners, and kitchen ranges and ovens

    SciTech Connect (OSTI)

    Not Available

    1993-11-01T23:59:59.000Z

    This document is divided into ``volumes`` B through E, dealing with individual classes of consumer products. Chapters in each present engineering analysis, base case forecasts, projected national impacts of standards, life-cycle costs and payback periods, impacts on manufacturers, impacts of standards on electric utilities, and environmental effects. Supporting appendices are included.

  6. Seismic diagnostics of mixing beyond the convective core in intermediate mass main-sequence stars

    E-Print Network [OSTI]

    B. L. Popielski; W. A. Dziembowski

    2005-05-25T23:59:59.000Z

    We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in such stars and this leads to ambiguities in modeling. Solar-like oscillations are expected to be excited in such objects. Frequencies of such oscillations provide diagnostics, which are sensitive to the structure of the innermost part of the star and they are known as the small separations. We construct evolutionary models of stars in this mass range assuming various scenarios for element mixing, which includes formation of element abundance jumps, as well as semiconvective and overshooting layers. We find that the three point small separations employing frequencies of radial and dipole modes provide the best probe of the element distribution above the convective core. With expected accuracy of frequency measurement from the space experiments, a discrimination between various scenarios should be possible.

  7. Vertical profiles of radar reflectivity of convective cells in tropical and mid-latitude mesoscale convective systems

    E-Print Network [OSTI]

    Lutz, Kurt Reed

    1992-01-01T23:59:59.000Z

    meteorological phenomenon of particular interest to forecasters is the mesoscale convective system (MCS). Chappell (1986) defines an MCS as "any multicellular storm or group of interacting storms that suggests some organization in its forcing". An MCS...VERTICAL PROFILES OF RADAR REFLECTIVITY OF CONVECTIVE CELLS IN TROPICAL AND MID-LATITUDE MESOSCALE CONVECTIVE SYSTEMS A Thesis by KURT REED LUTZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  8. Application of the 85 GHz ice scattering signature to a global study of mesoscale convective systems

    E-Print Network [OSTI]

    Devlin, Karen Irene

    1995-01-01T23:59:59.000Z

    It has long been observed that tropical convection tends to cluster, organizing into multicellular mesoscale convective systems (MCS), In convective towers, updrafts on the order of 10 m s-I favor the formation of large, precipitation-sized ice...

  9. Air convection noise of pencil-beam interferometer for long trace profiler

    E-Print Network [OSTI]

    Yashchuk, Valeriy V.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Takacs, Peter Z.

    2006-01-01T23:59:59.000Z

    Air Convection Noise of Pencil-beam Interferometer for Longwe investigate the effect of air convection on laser-beamshown that the NPD spectra due to air convection have a very

  10. The QBO's influence on lightning production and deep convection in the tropics

    E-Print Network [OSTI]

    Hernandez, Celina Anne

    2009-05-15T23:59:59.000Z

    ) flash densities and ten years (1998-2007) of TRMM Precipitation Radar (PR) deep convective and stratiform rainfall and convective echo top heights are analyzed. The QBO can be linked to deep convection through two hypothesized mechanisms: 1) modulation...

  11. Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK AND WILLIAM R. COTTON

    E-Print Network [OSTI]

    Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK (Manuscript received 30 December 2005, in final form 4 October 2006) ABSTRACT Mesoscale convective systems of usefulness in operational forecasting. 1. Introduction Mesoscale convective systems (MCSs) frequently de

  12. About convective heat transfer in geothermal systems

    SciTech Connect (OSTI)

    Pashkevich, R.I. [Kamchatsky Complex Department of NIPIgeotherm Institute, Petropavlovsk-Kamchatsky (Russian Federation)

    1996-12-31T23:59:59.000Z

    The interphase fluid-rock heat exchange in convective beat transfer in geothermal systems is investigated Nonlinear model of interphase heat exchange is suggested. Calculation for one dimension case and comparison with known Anzelius-Schumann solution is presented Generalized type block heat transfer model is formulated. The model is adequate for case of geothermal systems and reservoir when a rock block size is comparable with filtration path length. Criterion equations for nonstationary coefficients of interphase heat exchange we presented these equations were obtained in laboratory experiments with diorites.

  13. Natural convection airflow measurement and theory

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.; Yamaguchi, Kenjiro

    1984-01-01T23:59:59.000Z

    Natural convection is a major mechanism for heat distribution in many passive solar buildings, especially those with sunspaces. To better understand this mechanism, observations of air velocities and temperatures have been made in 13 different houses that encompass a wide variety of one- and two-story geometries. This paper extends previous reports. Results from one house are described in detail, and some generalizations are drawn from the large additional mass of data taken. A simple mathematical model is presented that describes the general nature of airflow and energy flow through an aperture.

  14. Improving Convective Parameterization Using ARM Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh School footballHydrogenITLaboratory inImproving Convective

  15. Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice

    SciTech Connect (OSTI)

    Gustafson, William I.; Ma, Po-Lun; Singh, Balwinder

    2014-12-01T23:59:59.000Z

    The physics suite of the Community Atmosphere Model version 5 (CAM5) has recently been implemented in the Weather Research and Forecasting (WRF) model to explore the behavior of the parameterization suite at high resolution and in the more controlled setting of a limited area model. The initial paper documenting this capability characterized the behavior for northern high latitude conditions. This present paper characterizes the precipitation characteristics for continental, mid-latitude, springtime conditions during the Midlatitude Continental Convective Clouds Experiment (MC3E) over the central United States. This period exhibited a range of convective conditions from those driven strongly by large-scale synoptic regimes to more locally driven convection. The study focuses on the precipitation behavior at 32 km grid spacing to better anticipate how the physics will behave in the global model when used at similar grid spacing in the coming years. Importantly, one change to the Zhang-McFarlane deep convective parameterization when implemented in WRF was to make the convective timescale parameter an explicit function of grid spacing. This study examines the sensitivity of the precipitation to the default value of the convective timescale in WRF, which is 600 seconds for 32 km grid spacing, to the value of 3600 seconds used for 2 degree grid spacing in CAM5. For comparison, an infinite convective timescale is also used. The results show that the 600 second timescale gives the most accurate precipitation over the central United States in terms of rain amount. However, this setting has the worst precipitation diurnal cycle, with the convection too tightly linked to the daytime surface heating. Longer timescales greatly improve the diurnal cycle but result in less precipitation and produce a low bias. An analysis of rain rates shows the accurate precipitation amount with the shorter timescale is assembled from an over abundance of drizzle combined with too little heavy rain events. With longer timescales one can improve the distribution, particularly for the extreme rain rates. Ultimately, without changing other aspects of the physics, one must choose between accurate diurnal timing and rain amount when choosing an appropriate convective timescale.

  16. Radio Frequency and Microwave Hazards Radio frequency (rf) and microwaves occur within the range 10 kHz to 300,000 MHz and are

    E-Print Network [OSTI]

    Shull, Kenneth R.

    kHz to 300,000 MHz and are used in rf ovens and furnaces, induction heaters, and microwave ovens. Microwave ovens are increasingly being used in laboratories for organic synthesis and digestion of analytical samples. Only microwave ovens designed for laboratory or industrial use should be used

  17. Convective heating analysis of an IFE target in a high temperature, low Reynolds number xenon environment

    E-Print Network [OSTI]

    Holdener, Dain Steffen

    2011-01-01T23:59:59.000Z

    OF THE THESIS Convective Heating Analysis of an IFE Targetto reduce the convective heating to the LEH windows and fuelpoint for more forceful heating simulations, placing less

  18. A numerical simulation of slantwise convection: its structure and evolution

    E-Print Network [OSTI]

    Overpeck, Scott Allen

    2001-01-01T23:59:59.000Z

    convection), and could be a possible explanation for frontal rainbands. This study uses the Penn State/NCAR Mesoscale Model (MM5) as a diagnostic tool to simulate a slantwise convective case from the Genesis of Atlantic Lows Experiment (GALE, Dirks et al...

  19. MPO 663 -Convective and Mesoscale Meteorology Brian Mapes, Spring 2008

    E-Print Network [OSTI]

    Miami, University of

    MPO 663 - Convective and Mesoscale Meteorology Brian Mapes, Spring 2008 I intend for students and mesoscale phenomena. 2. Working understanding of several of these tools, cultivated via homework, including. A sense of how convective and mesoscale phenomena fit into larger scales, gained via short current

  20. UNCORRECTED Grid geometry effects on convection in ocean climate models

    E-Print Network [OSTI]

    Kuhlbrodt, Till

    UNCORRECTED PROOF Grid geometry effects on convection in ocean climate models: a conceptual study is the 12 improvement of convection parameterization schemes, but the question of grid geometry also plays to an at- 14 mosphere model. Such ocean climate models have mostly structured, coarsely resolved grids. 15

  1. FLUCTUATIONS NEAR THE CONVECTIVE INSTABILITY IN A CHOLESTERIC LIQUID CRYSTAL

    E-Print Network [OSTI]

    Boyer, Edmond

    . For sufficiently strong heating, it is pos- sible for the buoyancy force to overcome the vis- cous shear forces convective pour une certaine valeur critique. A cause du couplage de modes induit par la force extérieure, la, drives the system into convective instability. It is found that, because of the mode coupling induced

  2. Drainage induced convection rolls in foams (revised version)

    E-Print Network [OSTI]

    Cox, Simon

    , where soap solution is added to the foam at constant flow rate, the irregular motion in the beer glass results for convection in quasi two-dimensional foams (monolayers of bubbles between two glass platesDrainage induced convection rolls in foams (revised version) S. Hutzler, S.J. Cox*, E. Janiaud

  3. Lesson 9 - Solar Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -ofLearningLensless4 Lensless Lesson 16 -

  4. Convection, granulation and period jitter in classical Cepheids

    E-Print Network [OSTI]

    Neilson, Hilding R

    2014-01-01T23:59:59.000Z

    Analyses of recent observations of the sole classical Cepheid in the Kepler field, V1154 Cygni, found random changes of about 30 minutes in the pulsation period. These period changes challenge standard theories of pulsation and evolution because the period change is non-secular, and explaining this period jitter is necessary for understanding stellar evolution and the role of Cepheids as precise standard candles. We suggest that convection and convective hot spots can explain the observed period jitter. Convective hot spots alter the timing of flux maximum and minimum in the Cepheid light curve, hence change the measured pulsation period. We present a model of random hot spots that generate a localized flux excess that perturbs the Cepheid light curve and consequently the pulsation period which is consistent with the observed jitter. This result demonstrates how important understanding convection is for modeling Cepheid stellar structure and evolution, how convection determines the red edge of the instability...

  5. Natural convection heat transfer from a plate in a semicircular enclosure

    SciTech Connect (OSTI)

    Moore, G.A.; Hollands, K.G.T. (Univ. of Waterloo, Ontario (Canada))

    1992-02-01T23:59:59.000Z

    The present paper is about characterizing the two-dimensional convective transfer across the air-filled region between a flat plate and a semicircular cylindrical enclosure. In the subject geometry, a long thin plate at uniform temperature is contained coaxially and symmetrically in a long semicircular trough closed at the top and having a uniform but different temperature. Heat flows across the air-filled region between the two by both natural convection and gaseous conduction. The problem of characterizing the free convective component of this heat transfer - that is, the component caused by bulk fluid motion - is treated experimentally by using a heat balance technique, with the measurements being repeated at different pressures, in order to cover a wide Rayleigh number range, from Ra {approximately} 10 to Ra {approximately} 10{sup 8}. Nusselt number versus Rayleigh number plots are presented for each of several combinations of plate-to-trough spacing and tilt angle, and the plots are correlated by equations. The problem of characterizing the conductive component is treated by numerically solving the steady diffusion equation in the air-filled region, and the results are correlated as a function of the spacing and the plate thickness.

  6. Natural convection in vertical parallel plates with an unheated entry or unheated exit

    SciTech Connect (OSTI)

    Lee, K.T. (Oriental Institute of Technology, Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering)

    1994-04-01T23:59:59.000Z

    This study aims to investigate the effects of the unheated entry or unheated exit section on the free convection heat transfer in air flow in vertical parallel plate channels resulting from the thermal boundary conditions of uniform heat flux (UHF) and uniform wall temperature (UWT). Results of average Nusselt number and dimensionless volume flow rate are presented in terms of the ratio of the length of heated section to the full channel length and a Rayleigh number, ranging from the limit for the fully developed flow to that for single-plate behavior. Analytical equations for dimensionless volume flow rate and average Nusselt number for both unheated restrictions and both thermal boundary conditions have been developed for the fully developed flow limit. The numerical solutions are shown to approach asymptotically the approximate solution for fully developed flow as the Rayleigh number approaches 1 or less. An important finding of the study is that an unheated exit characterizes greater total heat transfer and volume flow rate than an unheated entry does. The presence of the unheated entry or unheated exit severely affects the convection process, especially at low Rayleigh number. A notable effect of an unheated exit on convection characteristics was found for the case of UHF at high Rayleigh number.

  7. The development of convective instability in relation to convective activity and synoptic systems in AVE IV

    E-Print Network [OSTI]

    Davis, James Gregory

    1979-01-01T23:59:59.000Z

    700 mb 500 mb 300 mb 100 mb 1. 8 2 54 3. 1' 6. 2 3. 8 5 64 7 5 15. 0 RMS Direction Error RNS ~Seed Error -1 -1 0. 5ms l. oms -1 -1 0. 8 m s 2. 0 m s -1 -1 10ms 3. 8ms -1 -1 2. 0 m s 5. 7 m s The rawinsonde data were supplemented by hourly... of Co ttee) 4' (Member) N. I (Member) (Head of Department) August 1979 ABSTRACT Tha Development of Convective Instability in Relation to ConVectiVe Activity and Synoptic Systems in AVE 1V, (August 1979$ James Gregory Davis, B. S. , Texas A&M...

  8. Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities

    E-Print Network [OSTI]

    Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D.

    2012-01-01T23:59:59.000Z

    of inkjet droplets ranges between 10 µm and 100 µm. Evaporation should still be limited by dif- fusion at this scale. Convection occurs in evaporating sessile droplets [12] where, in order to conserve mass, evaporating liquid is replenished by a convective... Controller CT-M3-02). High-purity water (MilliQ) or ethanol filtered through a 0.45 µm pore filter were used as the fluids. Shadowgraph profile images of the droplets were produced using side illumination. A cold LED light source (Beaglehole instruments...

  9. Innovative coke oven gas cleaning system for retrofit applications. Quarterly environmental monitoring report No. 3, January 1, 1991--December 31, 1991

    SciTech Connect (OSTI)

    Not Available

    1992-10-16T23:59:59.000Z

    Bethlehem Steel Corporation (BSC), in conjunction with the Department of Energy (DOE) is conducting a Clean Coal Technology (CCT) project at its Sparrows Point, Maryland Coke Oven Plant. This project combines several existing technologies into an integrated system for removing impurities from Coke Oven Gas (COG) to make it an acceptable fuel. DOE is providing cost-sharing under a Cooperative Agreement with BSC. This Cooperative Agreement requires BSC to develop and conduct an Environmental Monitoring Plan (EMP) for the Clean Coal Technology project and to report the status of the EMP on a quarterly basis. This report is the third quarterly status report of the EMP. It covers the Environmental Monitoring Plan activities for the full year of 1991 from January 1, 1991 through December 31, 1991, including the forth quarter. See Sections 2, 3 and 4 for status reports of the Project Installation and Commissioning, the Environmental Monitoring activities and the Compliance Monitoring results for the period. Section 5 contains a list of Compliance Reports submitted to regulatory agencies during the period. The EMP describes in detail the environmental monitoring activities to be performed during the project execution. The purpose of the EMP is to: (1) document the extent of compliance of monitoring activities, i.e. those monitoring required to meet permit requirements, (2) confirm the specific impacts predicted in the National Environmental Policy Act documentation, and (3) establish an information base for the assessment of the environmental performance of the technology demonstrated by the project.

  10. Natural convection heat transfer from two horizontal cylinders

    SciTech Connect (OSTI)

    Reymond, Olivier; Murray, Darina B. [Department of Mechanical and Manufacturing Engineering, Trinity College Dublin (Ireland); O'Donovan, Tadhg S. [School of Engineering and Physical Sciences, Heriot-Watt University, Nasmyth Building, Edinburgh EH14 4AS (United Kingdom)

    2008-09-15T23:59:59.000Z

    Natural convection heat transfer from a single horizontal cylinder and a pair of vertically aligned horizontal cylinders is investigated. Surface heat transfer distributions around the circumference of the cylinders are presented for Rayleigh numbers of 2 x 10{sup 6}, 4 x 10{sup 6} and 6 x 10{sup 6} and a range of cylinder spacings of 1.5, 2 and 3 diameters. With a cylinder pairing the lower cylinder is unaffected by the presence of the second cylinder; the same is true of the upper cylinder if the lower one is not heated. However, when both cylinders are heated it has been found that a plume rising from the heated lower cylinder interacts with the upper cylinder and significantly affects the surface heat transfer distribution. Spectral analysis of surface heat transfer signals has established the influence of the plume oscillations on the heat transfer. Thus, when the plume from the lower cylinder oscillates out of phase with the flow around the upper cylinder it increases the mixing and results in enhanced heat transfer. (author)

  11. Convective effects in a regulatory and proposed fire model

    SciTech Connect (OSTI)

    Wix, S.D. [GRAM, Inc., Albuquerque, NM (United States); Hohnstreiter, G.F. [Sandia National Labs., Albuquerque, NM (United States). Transportation System Development Dept.

    1995-12-31T23:59:59.000Z

    Radiation is the dominant mode of heat transfer in large fires. However, convection can be as much as 10 to 20 percent of the total heat transfer to an object in a large fire. The current radioactive material transportation packaging regulations include convection as a mode of heat transfer in the accident condition scenario. The current International Atomic Energy Agency Safety Series 6 packaging regulation states ``the convection coefficient shall be that value which the designer can justify if the package were exposed to the specified fire``. The current Title 10, Code of Federal Regulations, Part 71 (10CFR71) packaging regulation states ``when significant, convection heat input must be included on the basis of still, ambient air at 800{degrees}C (1475{degrees}F)``. Two questions that can arise in an analysts mind from an examination of the packaging regulations is whether convection is significant and whether convection should be included in the design analysis of a radioactive materials transportation container. The objective of this study is to examine the convective effects on an actual radioactive materials transportation package using a regulatory and a proposed thermal boundary condition.

  12. Estimates of achievable potential for electricity efficiency improvements in U.S. residences

    E-Print Network [OSTI]

    Brown, Richard

    1993-01-01T23:59:59.000Z

    include induction cooktop and convection oven. (11) Furnace7.46 HSPF) Induction cooktop and improved oven (post-1995)7.46 HSPF) Induction cooktop and improved oven (post-1995)

  13. Science & Cooking SPU-27 Fall 2012 Lab 5: Molten chocolate cake & ice cream

    E-Print Network [OSTI]

    Wolfe, Patrick J.

    pot · 1 induction burner · 8 ramekins · 1 medium bowl (wet ingredients) · 1 spoon · 1 knife · 1 whisk · 1 spatula · 1 oven mitt · 1 convection oven-stick baking spray Procedure: 1. Preheat the oven to 350°F (=177 °C

  14. Numerical and Experimental Modeling of Natural Convection for a Cryogenic Prototype of a Titan

    E-Print Network [OSTI]

    Colonius, Tim

    in Sutherland's law D = diameter g = gravitation acceleration h = convection coefficient k = thermal

  15. Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure Keywords: Supercritical pressure Aviation kerosene Convective heat transfer Numerical study a b s t r a c convective in kerosene pipe flow is complicated. Here the convective heat transfer characteristics of China

  16. PHYSICS OF FLUIDS 25, 044105 (2013) Onset of buoyancy-driven convection in Cartesian

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    2013-01-01T23:59:59.000Z

    the onset of buoyancy-driven convection relevant to subsurface carbon dioxide sequestration in confined

  17. A viscous-convective instability in laminar Keplerian thin discs. II. Anelastic approximation

    E-Print Network [OSTI]

    Shakura, N

    2015-01-01T23:59:59.000Z

    Using the anelastic approximation of linearised hydrodynamic equations, we investigate the development of axially symmetric small perturbations in thin Keplerian discs. The sixth-order dispersion equation is derived and numerically solved for different values of relevant physical parameters (viscosity, heat conductivity, disc semi-thickness and vertical structure). The analysis reveals the appearance of two overstable modes which split out from the classical Rayleigh inertial modes in a wide range of the parameters in both ionized and neutral gases. These modes have a viscous-convective nature and can serve as a seed for turbulence in astrophysical discs even in the absence of magnetic fields.

  18. Total lightning characteristics of ordinary convection

    E-Print Network [OSTI]

    Motley, Shane Michael

    2009-06-02T23:59:59.000Z

    processes involved in the electrical development of thunderstorms. Nine of the thunderstorm cases examined occurred within range of Vaisala Inc.'s Dallas-Fort Worth (DFW) Lightning Detection and Ranging (LDAR) network and the other thirteen cases occurred...

  19. 4/3/12 2:13 PMMantle Convection: Earth's Interior Page 1 of 3http://conman.geos.vt.edu/~sdk/mantle/interior.html

    E-Print Network [OSTI]

    Smith-Konter, Bridget

    spherical shells: the crust, the mantle, and the core. The crust ranges from 6 to 70 kilometers thick minerals and the liquid iron outer core. #12;4/3/12 2:13 PMMantle Convection: Earth's Interior Page 2 of 3, O) in the Sun's outer corona and show no indication of chemical alteration since their formation

  20. Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 136: 333353, January 2010 Part B Modelling convective processes during the suppressed phase

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    NASA Langley Research Center, USA d European Centre for Medium Range Weather Forecasts, Reading, UK e, Chinese Academy of Meteorological Sciences, China iMet Office, Exeter, UK jLawrence Livermore National evolution of convection is assessed as part of a Global Energy and Water Cycle Experiment Cloud System Study

  1. Overshooting Convection from High-resolution NEXRAD Observations

    E-Print Network [OSTI]

    Solomon, David

    2014-01-09T23:59:59.000Z

    of the Rocky Mountains. Overshooting convection is most common over the high plains, and there is a pronounced seasonal and diurnal cycle present. The majority of overshooting systems occur during the warm season, and a diurnal maximum of overshooting occurs...

  2. Theory for induced convection experiments in the tokamak edge

    E-Print Network [OSTI]

    Theory for induced convection experiments in the tokamak edge P. Helander1 , D.D. Ryutov2 , and R National Laboratory, Livermore, USA By biasing alternate divertor plates in a tokamak, one can create

  3. atmospheric convective boundary: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    convective conditions is found to be primarily due to variations in mixed layer wind speed. Low-level winds thus play the major role in regulating the ability of thermals to...

  4. Experimental Investigation of Natural Convection in Trombe Wall Systems

    E-Print Network [OSTI]

    Chen, B.; Zhao, J.; Chen, C.; Zhuang, Z.

    2006-01-01T23:59:59.000Z

    In this paper, experiments with a passive solar building with Trombe wall in the north cold climate are carried out and discussed, and the natural convection heat transfer process has been investigated. The relativity of the factors affecting indoor...

  5. Identification of Robust Terminal-Area Routes in Convective Weather

    E-Print Network [OSTI]

    Balakrishnan, Hamsa

    Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System, especially during summer. Traffic flow management algorithms require reliable forecasts of route blockage ...

  6. Effects of aerosols on deep convective cumulus clouds

    E-Print Network [OSTI]

    Fan, Jiwen

    2009-05-15T23:59:59.000Z

    This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed...

  7. Identification of Robust Routes using Convective Weather Forcasts

    E-Print Network [OSTI]

    Michalek, Diana

    Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System (NAS), especially during summer months when travel demand is high. This has been the motivation for Air ...

  8. Survey and evaluation of techniques to augment convective heat transfer

    E-Print Network [OSTI]

    Bergles A. E.

    1965-01-01T23:59:59.000Z

    This report presents a survey and evaluation of the numerous techniques which have been shown to augment convective heat transfer. These techniques are: surface promoters, including roughness and treatment; displaced ...

  9. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    E-Print Network [OSTI]

    Gadgil, Ashok; Bauman, Fred; Kammerud, Ronald

    2008-01-01T23:59:59.000Z

    effect of the adjacent conditioned zones was properly accounted for by the BLASTeffects of this observation on the accuracy of results from the programs, the convection code was used iteratively with BLAST

  10. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,

  11. Land-atmosphere interaction and radiative-convective equilibrium

    E-Print Network [OSTI]

    Cronin, Timothy (Timothy Wallace)

    2014-01-01T23:59:59.000Z

    I present work on several topics related to land-atmosphere interaction and radiative-convective equilibrium: the first two research chapters invoke ideas related to land-atmosphere interaction to better understand ...

  12. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, F.; Kammerud, R.

    1981-04-01T23:59:59.000Z

    Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

  13. Vertical convection in neutrino-dominated accretion flows

    E-Print Network [OSTI]

    Liu, Tong; Kawanaka, Norita; Li, Ang

    2015-01-01T23:59:59.000Z

    We present the effects of the vertical convection on the structure and luminosity of the neutrino-dominated accretion flow (NDAF) around a stellar-mass black hole in spherical coordinates. We found that the convective energy transfer can suppress the radial advection in the NDAF, and that the density, temperature and opening angle are slightly changed. As a result, the neutrino luminosity and annihilation luminosity are increased, which is conducive to achieve the energy requirement of gamma-ray bursts.

  14. Possible solar cycle variations in the convection zone

    E-Print Network [OSTI]

    Sarbani Basu; H. M. Antia

    2000-01-26T23:59:59.000Z

    Using data from the Global Oscillations Network Group (GONG) that covers the period from 1995 to 1998 we study the change in frequencies of solar oscillations with solar activity. From these frequencies we attempt to determine any possible variation in solar structure with solar activity. We do not find any evidence of a change in the convection zone depth or extent of overshoot below the convection zone during the solar cycle.

  15. Natural convection airflow and heat transport in buildings: experimental results

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.

    1985-01-01T23:59:59.000Z

    Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

  16. Light beam range finder

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1998-01-01T23:59:59.000Z

    A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.

  17. Light beam range finder

    DOE Patents [OSTI]

    McEwan, T.E.

    1998-06-16T23:59:59.000Z

    A ``laser tape measure`` for measuring distance is disclosed which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%. 7 figs.

  18. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2015-01-01T23:59:59.000Z

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak.more »The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less

  19. Thermal effects of Kohout convection in the Bahamas and Florida

    SciTech Connect (OSTI)

    Simms, M.A.

    1985-01-01T23:59:59.000Z

    Kohout convection is a low-temperature groundwater thermal convection process in carbonate platform margins. It was first conceived of and postulated to occur in the subsurface of Florida by Francis Kohout in the 1960's. The flow is driven by buoyancy arising from subsurface differences in salinity and in temperature. Cold, dense seawater surrounding a platform at depth migrates inward, displacing warmer pore waters at the same elevation. This inflowing density current is in turn warmed within the platform and is buoyed upward to discharge on the platform shelf or margin resulting in a giant convective half-cell. In isolated platforms, such as the Bahamas, temperature differences alone drive Kohout convection. In Florida, the regional meteoric flow of the Floridan Aquifer mixes by dispersion with the convecting seawater resulting in an enhanced flow rate. Approximate analytical and numerical solutions of the governing differential equations allow the interactions of the flow and temperature fields to be determined. Permeability characteristics and platform margin geometry are the principal controls of the thermal structure and groundwater flow pattern in isolated platforms. In Florida, regional flow strength is also a control. High horizontal permeabilities (100 md to 1 darcy and higher) and tall, steep margins (1 km height, 30/sup 0/ slope) allow Kohout convection to penetrate 30 to 50 km inland causing substantial cooling. It may thus be a control of thermal evolution of the Florida-Bahamas Basin as well as parts of other sedimentary basins.

  20. Evolution of vertical drafts and cloud-to-ground lightning within the convective region of a mesoscale convective complex

    E-Print Network [OSTI]

    Saul, Scott Henry

    1995-01-01T23:59:59.000Z

    The evolution of the area-averaged vertical velocity within the objectively defined convective region of the 4 June 1985 PRE-STORM (Preliminary Regional Experiment for Stormscale Operational and Research Meteorology-Central Phase) mesoscale...

  1. The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems

    E-Print Network [OSTI]

    Restivo, Michael Edward

    1995-01-01T23:59:59.000Z

    suggested that the threshold of about 40 dBZ at the -10 C level for rapid cloud electrification found in New Mexico by Dye et al. (1989) could be valid for tropical convection as well. Orville and Henderson (1986), and Goodman and Christian (1993), have... along with small ice and supercooled liquid water for cloud electrification and lightning to occur. Since most oceanic VPRR drop off rapidly above the freezing level compared to continental VPRR, this would provide evidence that the updraft velocities...

  2. Process for separating, especially in multiple stages, acid components such as CO/sub 2/, HCN and specifically H/sub 2/S, from gases, especially from coke oven gases, by means of ammonia recirculation scrubbing

    SciTech Connect (OSTI)

    Bauer, H.K.; Otte, E.A.W.

    1984-10-16T23:59:59.000Z

    A process of separating in multiple stages acid components in coke oven gas such as CO/sub 2/, HCN and particularly H/sub 2/S by ammonia scrubbing wherein the ammonia used in scrubbing is deacidified to remove the acid components and is recirculated to the scrubbing process at least in part as substantially pure liquid ammonia.

  3. Direct numerical simulations of convective heat transfer

    SciTech Connect (OSTI)

    Pointel, G.; Acharya, S.; Sharma, C. [Louisiana State Univ., Baton Rouge, LA (United States). Mechanical Engineering Dept.

    1996-11-01T23:59:59.000Z

    This paper deals with the development of a direct numerical simulation (DNS) code for solving the incompressible Navier-Stokes equation using higher order finite difference schemes. The time dependent Navier Stokes equation has been discretized using semi-implicit second order time splitting scheme, which requires the solution of pressure Poisson equation. For this purpose a Galerkin Fourier transform in the spanwise direction and a matrix diagonalization technique is used. The convection terms are formulated in non-conservative form on a collocated grid. A fifth order upwind biased scheme is used for this purpose. Diffusion terms are differenced using a sixth order central difference scheme. The algorithm is implemented on the MasPar MP-1, a Single Instruction Multiple Data computer where efficient data parallelization is used to get DNS results. The code has been used to get results for smooth channel flow at Re{sub {tau}} = 180. Results are now being obtained for the energy equation and for flow in a periodic ribbed channel.

  4. EVIDENCE FOR CONVECTION IN SUNSPOT PENUMBRAE

    SciTech Connect (OSTI)

    Bharti, L.; Solanki, S. K.; Hirzberger, J., E-mail: bharti@mps.mpg.d [Max-Planck-Institute fuer sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau (Germany)

    2010-10-20T23:59:59.000Z

    We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from 30{sup 0} to 48{sup 0} using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI) on board Hinode. The relations of the twisting motions to the filament brightness and the position within the filament and within the penumbra, respectively, are investigated. Only certain portions of the filaments show twisting motions. In a statistical sense, the part of the twisting portion of a filament located closest to the umbra is brightest and possesses the fastest twisting motion, with a mean twisting velocity of 2.1 km s{sup -1}. The middle and outer sections of the twisting portion of the filament (lying increasingly further from the umbra), which are less bright, have mean velocities of 1.7 km s{sup -1} and 1.35 km s{sup -1}, respectively. The observed reduction of brightness and twisting velocity toward the outer section of the filaments may be due to reducing upflow along the filament's long axis. No significant variation of twisting velocity as a function of viewing angles was found. The obtained correlation of brightness and velocity suggests that overturning convection causes the twisting motions observed in penumbral filament and may be the source of the energy needed to maintain the brightness of the filaments.

  5. Dynamic Transitions of Surface Tension Driven Convection

    E-Print Network [OSTI]

    Henk Dijkstra; Taylan Sengul; Shouhong Wang

    2011-05-05T23:59:59.000Z

    We study the well-posedness and dynamic transitions of the surface tension driven convection in a three-dimensional (3D) rectangular box with non-deformable upper surface and with free-slip boundary conditions. It is shown that as the Marangoni number crosses the critical threshold, the system always undergoes a dynamic transition. In particular, two different scenarios are studied. In the first scenario, a single mode losing its stability at the critical parameter gives rise to either a Type-I (continuous) or a Type-II (jump) transition. The type of transitions is dictated by the sign of a computable non-dimensional parameter, and the numerical computation of this parameter suggests that a Type-I transition is favorable. The second scenario deals with the case where the geometry of the domain allows two critical modes which possibly characterize a hexagonal pattern. In this case we show that the transition can only be either a Type-II or a Type-III (mixed) transition depending on another computable non-dimensional parameter. We only encountered Type-III transition in our numerical calculations. The second part of the paper deals with the well-posedness and existence of global attractors for the problem.

  6. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, S.H.

    1988-03-10T23:59:59.000Z

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

  7. Startup and initial operation of a DFGD and pulse jet fabric filter system on Cokenergy's Indiana Harbor coke oven off gas system

    SciTech Connect (OSTI)

    Morris, W.J.; Gansley, R.R.; Schaddell, J.G.

    1999-07-01T23:59:59.000Z

    This paper describes the design, initial operation and performance testing of a Dry Flue Gas Desulfurization (DFGD) and Modular Pulse Jet Fabric Filter (MPJFF) system installed at Cokenergy's site in East Chicago, Indiana. The combined flue gas from the sixteen (16) waste heat recovery boilers is processed by the system to control emissions of sulfur dioxide and particulates. These boilers recover energy from coke oven off gas from Indiana Harbor Coke Company's coke batteries. The DFGD system consists of two 100% capacity absorbers. Each absorber vessel uses a single direct drive rotary atomizer to disperse the lime slurry for SO{sub 2} control. The MPJFF consists of thirty two (32) modules arranged in twin sixteen-compartment (16) units. The initial start up of the DFGD/MPJFF posed special operational issues due to the low initial gas flows through the system as the four coke oven batteries were cured and put in service for the first time. This occurred at approximately monthly intervals beginning in March 1998. A plan was implemented to perform a staged startup of the DFGD and MPJFF to coincide with the staged start up of the coke batteries and waste heat boilers. Operational issues that are currently being addressed include reliability of byproduct removal. Performance testing was conducted in August and September 1998 at the inlet of the system and the outlet stack. During these tests, particulate, SO{sub 2}, SO{sub 3}, and HCI emissions were measured simultaneously at the common DFGD inlet duct and the outlet stack. Measurements were also taken for average lime, water, and power consumption during the tests as well as system pressure losses. These results showed that all guarantee parameters were achieved during the test periods. The initial operation and performance testing are described in this paper.

  8. A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone

    E-Print Network [OSTI]

    Francis J. Robinson; Kwing L. Chan

    2000-11-21T23:59:59.000Z

    We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.

  9. Range of Glaciers: The Exploration of the Northern Cascade Range

    E-Print Network [OSTI]

    Hook, Robert D.

    2006-01-01T23:59:59.000Z

    Review: Range of Glaciers: The Exploration of the NorthernUSA Fred Beckey. Range of Glaciers: The Exploration of thewill find that Range of Glaciers is a must read. The book

  10. Analysis of 11 june 2003 mesoscale convective vortex genesis using weather surveillance radar ??88 doppler (wsr-88d) 

    E-Print Network [OSTI]

    Reynolds, Amber Elizabeth

    2009-05-15T23:59:59.000Z

    Mesoscale convective vortices (MCVs), which typically form within the stratiform rain of some mesoscale convective systems (MCSs), may persist for days, often regenerating convection daily. Long-lived MCVs can produce as much precipitation as a...

  11. Analysis of 11 june 2003 mesoscale convective vortex genesis using weather surveillance radar ??88 doppler (wsr-88d)

    E-Print Network [OSTI]

    Reynolds, Amber Elizabeth

    2009-05-15T23:59:59.000Z

    Mesoscale convective vortices (MCVs), which typically form within the stratiform rain of some mesoscale convective systems (MCSs), may persist for days, often regenerating convection daily. Long-lived MCVs can produce as much precipitation as a...

  12. Efficient small-scale dynamo in solar convection zone

    E-Print Network [OSTI]

    Hotta, H; Yokoyama, T

    2015-01-01T23:59:59.000Z

    We investigate small-scale dynamo action in the solar convection zone through a series of high resolution MHD simulations in a local Cartesian domain with 1$R_\\odot$ (solar radius) of horizontal extent and a radial extent from 0.715 to 0.96$R_\\odot$. The dependence of the solution on resolution and diffusivity is studied. For a grid spacing of less than 350 km, the root mean square magnetic field strength near the base of the convection zone reaches 95% of the equipartition field strength (i.e. magnetic and kinetic energy are comparable). For these solutions the Lorentz force feedback on the convection velocity is found to be significant. The velocity near the base of the convection zone is reduced to 50% of the hydrodynamic one. In spite of a significant decrease of the convection velocity, the reduction in the enthalpy flux is relatively small, since the magnetic field also suppresses the horizontal mixing of the entropy between up- and downflow regions. This effect increases the amplitude of the entropy pe...

  13. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  14. Eects of thermo-chemical mantle convection on the thermal evolution of the Earth's core

    E-Print Network [OSTI]

    Tackley, Paul J.

    E¡ects of thermo-chemical mantle convection on the thermal evolution of the Earth's core Takashi in the core with a fully dynamic thermo-chemical mantle convection model is developed to investigate

  15. Hydration of the lower stratosphere by ice crystal geysers over land convective systems

    E-Print Network [OSTI]

    Khaykin, S.

    The possible impact of deep convective overshooting over land has been explored by six simultaneous soundings of water vapour, particles and ozone in the lower stratosphere next to Mesoscale Convective Systems (MCSs) during ...

  16. Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01T23:59:59.000Z

    A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...

  17. The influence of convective activity on the vorticity budget 

    E-Print Network [OSTI]

    Townsend, Tamara L

    1987-01-01T23:59:59.000Z

    . Continued. ~E' i~ QE I ~ tt Jtm a tt NE v~ l / tmt ta' NE ~~f IIIY G NE~~ NE a/+ NE NE NE NE 1st NE Fig. 13. Radar summary for 1435 GNT 10 Apri. l 1979. NE I l. c I E j~7 ~ NE NE MP- Qo+ Fig. 14. Radar summary for 2235 GMT 10 April 1979... experiment. 15 3 Average values of terms in the vorticity equation for a convective (Area 1) and a nonconvective (Area 2) area during AVE VII. Units of 10 s 145 4 Average values of terms in the vorticity equation for a convective (Area 1) and a...

  18. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-01T23:59:59.000Z

    Convective processes play a critical role in the Earth’s energy balance through the redistribution of heat and moisture in the atmosphere and subsequent impacts on the hydrologic cycle. Global observation and accurate representation of these processes in numerical models is vital to improving our current understanding and future simulations of Earth’s climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales that are associated with convective and stratiform precipitation processes; therefore, they must turn to parameterization schemes to represent these processes. In turn, the physical basis for these parameterization schemes needs to be evaluated for general application under a variety of atmospheric conditions. Analogously, space-based remote sensing algorithms designed to retrieve related cloud and precipitation information for use in hydrological, climate, and numerical weather prediction applications often rely on physical “parameterizations” that reliably translate indirectly related instrument measurements to the physical quantity of interest (e.g., precipitation rate). Importantly, both spaceborne retrieval algorithms and model convective parameterization schemes traditionally rely on field campaign data sets as a basis for evaluating and improving the physics of their respective approaches. The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

  19. Submitted to Geophysical and Astrophysical Fluid Dynamics Shear and Mixing in Oscillatory Doubly Di usive Convection

    E-Print Network [OSTI]

    Paparella, Francesco

    convection are found in the Earth's oceans, most notably, below the polar ice caps. There melting ice

  20. Scaling behavior in the convection-driven Brazil-nut effect

    E-Print Network [OSTI]

    Prakhyat Hejmady; Ranjini Bandyopadhyay; Sanjib Sabhapandit; Abhishek Dhar

    2012-11-22T23:59:59.000Z

    The Brazil-nut effect is the phenomenon in which a large intruder particle immersed in a vertically shaken bed of smaller particles rises to the top, even when it is much denser. The usual practice, while describing these experiments, has been to use the dimensionless acceleration \\Gamma=a \\omega^2/g, where a and \\omega are respectively the amplitude and the angular frequency of vibration and g is the acceleration due to gravity. Considering a vibrated quasi-two-dimensional bed of mustard seeds, we show here that the peak-to-peak velocity of shaking v= a\\omega, rather than \\Gamma, is the relevant parameter in the regime where boundary-driven granular convection is the main driving mechanism. We find that the rise-time \\tau of an intruder is described by the scaling law \\tau ~ (v-v_c)^{-\\alpha}, where v_c is identified as the critical vibration velocity for the onset of convective motion of the mustard seeds. This scaling form holds over a wide range of (a,\\omega), diameter and density of the intruder.

  1. EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER OF IONIC LIQUID IN A RECTANGULAR ENCLOSURE HEATED FROM BELOW

    SciTech Connect (OSTI)

    Fox, E.; Visser, A.; Bridges, N.

    2011-07-18T23:59:59.000Z

    This paper presents an experimental study of natural convection heat transfer for an Ionic Liquid. The experiments were performed for 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C{sub 4}mmim][NTf{sub 2}]) at a Raleigh number range of 1.26 x 10{sup 7} to 8.3 x 10{sup 7}. In addition to determining the convective heat transfer coefficients, this study also included experimental determination of thermophysical properties of [C{sub 4}mmim][NTf{sub 2}] such as, density, viscosity, heat capacity, and thermal conductivity. The results show that the density of [C{sub 4}mmim][NTf{sub 2}] varies from 1.437-1.396 g/cm{sup 3} within the temperature range of 10-50 C, the thermal conductivity varies from 0.105-0.116 W/m.K between a temperature of 10 to 60 C, the heat capacity varies from 1.015 J/g.K - 1.760 J/g.K within temperature range of 25-340 C and the viscosity varies from 18cp-243cp within temperature range 10-75 C. The results for density, thermal conductivity, heat capacity, and viscosity were in close agreement with the values in the literature. Measured dimensionless Nusselt number was observed to be higher for the ionic liquid than that of DI water. This is expected as Nusselt number is the ratio of heat transfer by convection to conduction and the ionic liquid has lower thermal conductivity (approximately 18%) than DI water.

  2. The ionospheric signature of transient dayside reconnection and the associated pulsed convection return ow

    E-Print Network [OSTI]

    Boyer, Edmond

    of convection. Key words. Ionosphere (plasma convection) á Magne- tospheric physics (magnetopause, cusp, 1996, and references therein) and the excitation of dayside convection is the focus of the present of magnetosheath plasma into the magneto- sphere, and the ionospheric plasma ¯ow at the footprint of the cusp

  3. THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS AND ANVIL

    E-Print Network [OSTI]

    THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS in the Simulation of Mesoscale Convective Systems and Anvil Clouds in the Tropical Western Pacific K. Van Weverberg1 cloud microphysics in the simulation of mesoscale convective systems (MCSs) in the tropical western

  4. Practical and Intrinsic Predictability of Severe and Convective Weather at the Mesoscales

    E-Print Network [OSTI]

    Practical and Intrinsic Predictability of Severe and Convective Weather at the Mesoscales at the mesoscales using convection-permitting ensemble simulations of a squall line and bow echo event during the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment (BAMEX) on 9­10 June 2003. Although most

  5. weber, evans, moser, and newell Air Traffic Management Decision Support During Convective Weather

    E-Print Network [OSTI]

    Reuter, Martin

    · weber, evans, moser, and newell Air Traffic Management Decision Support During Convective WeatherTraffic Management Decision Support During Convective Weather Mark E. Weber, James E. Evans, William R. Moser algorithm. #12;· weber, evans, moser, and newell Air Traffic Management Decision Support During Convective

  6. Charge rearrangement by sprites over a north Texas mesoscale convective system

    E-Print Network [OSTI]

    Cummer, Steven A.

    Charge rearrangement by sprites over a north Texas mesoscale convective system William W. Hager,1 is analyzed for a mesoscale convective system (MCS) situated in north Texas and east New Mexico on 15 July. Lapierre (2012), Charge rearrangement by sprites over a north Texas mesoscale convective system, J. Geophys

  7. Patterns of Precipitation and Mesolow Evolution in Midlatitude Mesoscale Convective Vortices

    E-Print Network [OSTI]

    Johnson, Richard H.

    Patterns of Precipitation and Mesolow Evolution in Midlatitude Mesoscale Convective Vortices ERIC P manifestations of mesoscale convective vortices (MCVs) that traversed Oklahoma during the periods May­August 2002 Profiler Network data. Forty-five MCVs that developed from mesoscale convective systems (MCSs) have been

  8. HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME

    E-Print Network [OSTI]

    Boyer, Edmond

    1 HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME P. H and the sheet metal: This is ventilation by natural convection. The remaining conductive heat from the sheet or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers

  9. Effect of shear and magnetic field on the heat-transfer efficiency of convection in rotating spherical shells

    E-Print Network [OSTI]

    Yadav, Rakesh K; Christensen, Ulrich R; Duarte, Lucia; Reiners, Ansgar

    2015-01-01T23:59:59.000Z

    We study rotating thermal convection in spherical shells as prototype for flow in the cores of terrestrial planets, gas planets or in stars. We base our analysis on a set of about 450 direct numerical simulations of the (magneto)hydrodynamic equations under the Boussinesq approximation. The Ekman number ranges from $10^{-3}$ to $10^{-6}$. Four sets of simulations are considered: non-magnetic simulations and dynamo simulations with either free-slip or no-slip flow boundary conditions. The non-magnetic setup with free-slip boundaries generates the strongest zonal flows. Both non-magnetic simulations with no-slip flow boundary conditions and self-consistent dynamos with free-slip boundaries have drastically reduced zonal-flows. Suppression of shear leads to a substantial gain in heat-transfer efficiency, increasing by a factor of 3 in some cases. Such efficiency enhancement occurs as long as the convection is significantly influenced by rotation. At higher convective driving the heat-transfer efficiency trends t...

  10. Does convective aggregation need to be represented in cumulus parameterizations?

    E-Print Network [OSTI]

    Does convective aggregation need to be represented in cumulus parameterizations? Isabelle Tobin,1 in phenomena such as ``hot spots'' or the Madden-Julian Oscillation. These findings support the need climate models lack any such representation. The ability of a cloud system- resolving model to reproduce

  11. NATURAL CONVECTION OF SUBCOOLED LIQUID NITROGEN IN A VERTICAL CAVITY

    E-Print Network [OSTI]

    Chang, Ho-Myung

    temperature superconductor) power devices, such as HTS transformers, fault current limiters, and terminals power transformer cooled by natural convection of subcooled liquid nitrogen. A liquid nitrogen bath of subcooled liquid nitrogen system for an HTS transformer, operating at around 65 K. This system consists

  12. Sparse grid collocation schemes for stochastic natural convection problems

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    stochastic methods and Monte-Carlo based sam- pling methods are two approaches that have been used to analyzeSparse grid collocation schemes for stochastic natural convection problems Baskar on the Smolyak algorithm offers a viable alternate method for solving high-dimensional stochastic partial

  13. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, B.A.; Siminovitch, M.

    1997-07-29T23:59:59.000Z

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

  14. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, Bruce A. (825 Manor Rd., El Sobrante, CA 94803); Siminovitch, Michael (829 Manor Rd., El Sobrante, CA 94803)

    1997-01-01T23:59:59.000Z

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures.

  15. EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING

    E-Print Network [OSTI]

    Eagar, Thomas W.

    EFFECTS OF SURFACE DEPRESSION AND CONVECTION IN GTA WELDING M.L. Lin, T.W. Eagar Materials of the weld pool which are changed by these fact ors . It is shown that, at current s in excess of 300 amperes in a different heat distribution on the weld pool surface . ALTHOUGH THE GAS tungsten arc (GTA) welding process

  16. Estimation of Convection Loss from Paraboloidal Dish Cavity Receivers

    E-Print Network [OSTI]

    In general, cavity receivers employed in the sun-tracking paraboloidal dish concentrator are subjected the numerical investigation of natural and combined convection loss from cavity receivers employed in solar is a significant source of energy loss from thermal receivers used with dish solar concentrators. This paper

  17. Modeling thermal convection in supradetachment basins: example from western Norway

    E-Print Network [OSTI]

    Andersen, Torgeir Bjørge

    Modeling thermal convection in supradetachment basins: example from western Norway A. SOUCHE*, M. DABROWSKI AND T. B. ANDERSEN Physics of Geological Processes (PGP), University of Oslo, Oslo, Norway basins of western Norway are examples of supradetachment basins that formed in the hanging wall

  18. The CHUVA Project how does convection vary across the Brazil?

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    1 The CHUVA Project ­ how does convection vary across the Brazil? Luiz A. T. Machado1 , Maria A. F de Previsão de Tempo e Estudos Climáticos (CPTEC), Brazil. 2. Universidade de São Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Brazil. 3. Departamento de Ciências e Tecnologia Espacial

  19. Symmetrybreaking instabilities of convection By A.M. Rucklidge

    E-Print Network [OSTI]

    Rucklidge, Alastair

    fluid layer is often modelled by considering a finite box with periodic boundary conditions in the two­dimensional convection in a plane layer of unit depth with periodic boundary conditions with equal wave numbers k oscillatory solutions are cre­ ated in a Hopf bifurcation. One of the three oscillations, alternating

  20. 'Butterfly effect' in porous Bénard convection heated from below

    SciTech Connect (OSTI)

    Siri, Z.; Liew, K. Y. [Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ibrahim, R. I. [Faculty of Science and Technology, Universiti Sains Islam Malaysia, 71800 Bandar Baru Nilai, Negeri Sembilan Darul Khusus (Malaysia)

    2014-07-10T23:59:59.000Z

    Transition from steady to chaos for the onset of Bénard convection in porous medium was analyzed. The governing equation is reduced to ordinary differential equation and solved using built in MATLAB ODE45. The transition from steady to chaos take over from a limit cycle followed by homoclinic explosion.

  1. Preparation, Biodistribution and Neurotoxicity of Liposomal Cisplatin following Convection Enhanced

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Preparation, Biodistribution and Neurotoxicity of Liposomal Cisplatin following Convection Enhanced delivery (CED) to F98 glioma bearing rats. Neurotoxicologic studies were carried out in non-tumor bearing. Unexpectedly, LipoplatinTM was highly neurotoxic when given i.c. by CED and resulted in death immediately

  2. Stellar Surface Convection, Line Asymmetries, and Wavelength Shifts

    E-Print Network [OSTI]

    , Box 43, SE­22100 Lund, Sweden Abstract. Wavelength positions of photospheric absorption lines may the sinking and cooler (darker) gas. For the Sun, the effect is around 300 m s \\Gamma1 , expected to increase), and intergranular lanes with local redshifts (sinking motion), as naturally expected in convective energy transfer

  3. Predicting flow reversals in chaotic natural convection using data assimilation

    E-Print Network [OSTI]

    Danforth, Chris

    . The thermosyphon, a type of natural convection loop or non-mechanical heat pump, can be likened to a toy model of climate. Thermosyphons are used in solar water heaters (Belessiotis and Mathiou- lakis, 2002), cooling) and other industrial applications. In these heat pumps, buoyant forces move fluid through a closed loop

  4. Nonequilibrium pattern formation and spatiotemporal chaos in fluid convection

    SciTech Connect (OSTI)

    Michael Cross

    2006-09-13T23:59:59.000Z

    The final report for grant number DE-FG03-98ER14891 summarizes the application of the unique simulation capabilities developed under DOE support to investigations of important issues in pattern formation and spatiotemporal chaos in Rayleigh-Benard convection, particularly emphasizing quantitative contact with the active experimental programs.

  5. OSCILLATORY FLOW FORCED CONVECTION IN MICRO HEAT SPREADERS

    E-Print Network [OSTI]

    Beskok, Ali

    transfer devices, micro heat pipes, based on capillary pumping of a multiphase ¯uid in microchannels, have-phase forced convection heat transfer and ¯ow characteristics of water in microchannels, both in the laminar) concept for ef cient transport of large, concentrated heat loads is introduced. The MHS is a single

  6. Development of Ensemble Neural Network Convection Parameterizations for Climate Models

    SciTech Connect (OSTI)

    Fox-Rabinovitz, M. S.; Krasnopolsky, V. M.

    2012-05-02T23:59:59.000Z

    The novel neural network (NN) approach has been formulated and used for development of a NN ensemble stochastic convection parametrization for climate models. This fast parametrization is built based on data from Cloud Resolving Model (CRM) simulations initialized with and forced by TOGA-COARE data. The SAM (System for Atmospheric Modeling), developed by D. Randall, M. Khairoutdinov, and their collaborators, has been used for CRM simulations. The observational data are also used for validation of model simulations. The SAM-simulated data have been averaged and projected onto the GCM space of atmospheric states to implicitly define a stochastic convection parametrization. This parametrization is emulated using an ensemble of NNs. An ensemble of NNs with different NN parameters has been trained and tested. The inherent uncertainty of the stochastic convection parametrization derived in such a way is estimated. Due to these inherent uncertainties, NN ensemble is used to constitute a stochastic NN convection parametrization. The developed NN convection parametrization have been validated in a diagnostic CAM (CAM-NN) run vs. the control CAM run. Actually, CAM inputs have been used, at every time step of the control/original CAM integration, for parallel calculations of the NN convection parametrization (CAM-NN) to produce its outputs as a diagnostic byproduct. Total precipitation (P) and cloudiness (CLD) time series, diurnal cycles, and P and CLD distributions for the large Tropical Pacific Ocean for the parallel CAM-NN and CAM runs show similarity and consistency with the NCEP reanalysis. The P and CLD distributions for the tropical area for the parallel runs have been analyzed first for the TOGA-COARE boreal winter season (November 1992 through February 1993) and then for the winter seasons of the follow-up parallel decadal simulations. The obtained results are encouraging and practically meaningful. They show the validity of the NN approach. This constitutes an important practical conclusion of the study: the obtained results on NN ensembles as a stochastic physics parametrization show a realistic possibility of development of NN convection parametrization for climate (and NWP) models based on learning cloud physics from CRM/SAM simulated data.

  7. Transport of Magnetic Fields in Convective, Accreting Supernova Cores

    E-Print Network [OSTI]

    Christopher Thompson; Norman Murray

    2001-05-24T23:59:59.000Z

    We consider the amplification and transport of a magnetic field in the collapsed core of a massive star, including both the region between the neutrinosphere and the shock, and the central, opaque core. An analytical argument explains why rapid convective overturns persist within a newly formed neutron star for roughly 10 seconds ($> 10^3$ overturns), consistent with recent numerical models. A dynamical balance between turbulent and magnetic stresses within this convective layer corresponds to flux densities in excess of $10^{15}$G. Material accreting onto the core is heated by neutrinos and also becomes strongly convective. We compare the expected magnetic stresses in this convective `gain layer' with those deep inside the neutron core. Buoyant motions of magnetized fluid are greatly aided by the intense neutrino flux. We calculate the transport rate through a medium containing free neutrons protons, and electrons, in the limiting cases of degenerate or non-degenerate nucleons. Fields stronger than $\\sim 10^{13}$ G are able to rise through the outer degenerate layers of the neutron core during the last stages of Kelvin-Helmholtz cooling (up to 10 seconds post-collapse), even though these layers have become stable to convection. We also find the equilibrium shape of a thin magnetic flux rope in the dense hydrostatic atmosphere of the neutron star, along with the critical separation of the footpoints above which the rope undergoes unlimited expansion against gravity. The implications of these results for pulsar magnetism are summarized, and applied to the case of late fallback over the first 1,000-10,000 s of the life of a neutron star

  8. MODELING THE DYNAMICAL COUPLING OF SOLAR CONVECTION WITH THE RADIATIVE INTERIOR

    SciTech Connect (OSTI)

    Brun, Allan Sacha [Laboratoire AIM Paris-Saclay, CEA/Irfu Universite Paris-Diderot CNRS/INSU, 91191 Gif-sur-Yvette (France); Miesch, Mark S. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States); Toomre, Juri [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309-0440 (United States)

    2011-12-01T23:59:59.000Z

    The global dynamics of a rotating star like the Sun involves the coupling of a highly turbulent convective envelope overlying a seemingly benign radiative interior. We use the anelastic spherical harmonic code to develop a new class of three-dimensional models that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R (with R the solar radius), thus encompassing part of the nuclear core up through most of the convection zone. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior, with a slow spreading that is here diffusively controlled. The rapid angular momentum redistribution in the convective envelope leads to a fast equator and slow poles, with a conical differential rotation achieved at mid-latitudes, much as has been deduced by helioseismology. The convective motions are able to overshoot downward about 0.04R into the radiative interior. However, the convective meridional circulation there is confined to a smaller penetration depth and is directed mostly equatorward at the base of the convection zone. Thermal wind balance is established in the lower convection zone and tachocline but departures are evident in the upper convection zone. Internal gravity waves are excited by the convective overshooting, yielding a complex wave field throughout the radiative interior.

  9. Revisiting the theoretical DBV (V777 Her) instability strip: the MLT theory of convection

    E-Print Network [OSTI]

    A. H. Córsico; L. G. Althaus; M. M. Miller Bertolami; E. Garc\\'\\ia-Berro

    2008-10-16T23:59:59.000Z

    We reexamine the theoretical instability domain of pulsating DB white dwarfs (DBV or V777 Her variables). We performed an extensive $g$-mode nonadiabatic pulsation analysis of DB evolutionary models considering a wide range of stellar masses, for which the complete evolutionary stages of their progenitors from the ZAMS, through the thermally pulsing AGB and born-again phases, the domain of the PG1159 stars, the hot phase of DO white dwarfs, and then the DB white dwarf stage have been considered. We explicitly account for the evolution of the chemical abundance distribution due to time-dependent chemical diffusion processes. We examine the impact of the different prescriptions of the MLT theory of convection and the effects of small amounts of H in the almost He-pure atmospheres of DB stars on the precise location of the theoretical blue edge of the DBV instability strip.

  10. COMPARING THE EFFECT OF RADIATIVE TRANSFER SCHEMES ON CONVECTION SIMULATIONS

    SciTech Connect (OSTI)

    Tanner, Joel D.; Basu, Sarbani; Demarque, Pierre [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2012-11-10T23:59:59.000Z

    We examine the effect of different radiative transfer schemes on the properties of three-dimensional (3D) simulations of near-surface stellar convection in the superadiabatic layer, where energy transport transitions from fully convective to fully radiative. We employ two radiative transfer schemes that fundamentally differ in the way they cover the 3D domain. The first solver approximates domain coverage with moments, while the second solver samples the 3D domain with ray integrations. By comparing simulations that differ only in their respective radiative transfer methods, we are able to isolate the effect that radiative efficiency has on the structure of the superadiabatic layer. We find the simulations to be in good general agreement, but they show distinct differences in the thermal structure in the superadiabatic layer and atmosphere.

  11. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-10T23:59:59.000Z

    The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available.

  12. Convection in multiphase flows using Lattice Boltzmann methods

    E-Print Network [OSTI]

    L. Biferale; P. Perlekar; M. Sbragaglia; F. Toschi

    2011-11-03T23:59:59.000Z

    We present high resolution numerical simulations of convection in multiphase flows (boiling) using a novel algorithm based on a Lattice Boltzmann method. We first validate the thermodynamical and kinematical properties of the algorithm. Then, we perform a series of 3d numerical simulations at changing the mean properties in the phase diagram and compare convection with and without phase coexistence at $Ra \\sim 10^7$. We show that in presence of nucleating bubbles non-Oberbeck Boussinesq effects develops, mean temperature profile becomes asymmetric, heat-transfer and heat-transfer fluctuations are enhanced. We also show that small-scale properties of velocity and temperature fields are strongly affected by the presence of buoyant bubble leading to high non-Gaussian profiles in the bulk.

  13. Dissipation Efficiency in Turbulent Convective Zones in Low Mass Stars

    E-Print Network [OSTI]

    Kaloyan Penev; Dimitar Sasselov; Frank Robinson; Pierre Demarque

    2009-09-26T23:59:59.000Z

    We extend the analysis of Penev et al. (2007) to calculate effective viscosities for the surface convective zones of three main sequence stars of 0.775Msun, 0.85Msun and the present day Sun. In addition we also pay careful attention to all normalization factors and assumptions in order to derive actual numerical prescriptions for the effective viscosity as a function of the period and direction of the external shear. Our results are applicable for periods that are too long to correspond to eddies that fall within the inertial subrange of Kolmogorov scaling, but no larger than the convective turnover time, when the assumptions of the calculation break down. We find linear scaling of effective viscosity with period and magnitudes at least three times larger than the Zahn (1966, 1989) prescription.

  14. The Critical Rayleigh Number in Horizontal Convection for $\\Pran=1$

    E-Print Network [OSTI]

    Sun, L; Sun, De-Jun; Sun, Liang

    2007-01-01T23:59:59.000Z

    We report the numerical simulations of the horizontal convection within a rectangle cavity tank at high Rayleigh numbers. The physical solution of horizontal convection depends the space resolution of the meshes. The mesh number $N$ is proportion to $Ra^{1/3}$. The unstable numerical solutions are obtained as $Npower law also implies that the space resolution is dominated by the viscosity and heat diffusion. It implies that the special resolution is dominated by viscosity and thermal diffusivity but the length of the tank. Moreover, there is a Hopf bifurcation from steady solutions to unsteady solutions and the critical Rayleigh number $Ra_c$ is obtained as $5.53\\times 10^8

  15. Diamagnetic pumping near the base of a stellar convection zone

    E-Print Network [OSTI]

    L. L. Kitchatinov; G. Rüdiger

    2008-02-18T23:59:59.000Z

    The property of inhomogeneous turbulence in conducting fluids to expel large-scale magnetic fields in the direction of decreasing turbulence intensity is shown as important for the magnetic field dynamics near the base of a stellar convection zone. The downward diamagnetic pumping confines a fossil internal magnetic field in the radiative core so that the field geometry is appropriate for formation of the solar tachocline. For the stars of solar age, the diamagnetic confinement is efficient only if the ratio of turbulent magnetic diffusivity of the convection zone to the (microscopic or turbulent) diffusivity of the radiative interiour is larger than 10^5. Confinement in younger stars require still larger diffusivity ratio. The observation of persistent magnetic structures on young solar-type stars can thus provide evidences for the nonexistence of tachoclines in stellar interiors and on the level of turbulence in radiative cores.

  16. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect (OSTI)

    Correia, James; Arritt, R.

    2008-11-01T23:59:59.000Z

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  17. THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect (OSTI)

    Murphy, Jeremiah W.; Dolence, Joshua C.; Burrows, Adam, E-mail: jmurphy@astro.princeton.edu, E-mail: jdolence@astro.princeton.edu, E-mail: burrows@astro.princeton.edu [Princeton University, Princeton, NJ (United States)

    2013-07-01T23:59:59.000Z

    Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the driving mechanism of the dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven simulations and propose scaling relations for neutrino-driven convection. Through these comparisons, we infer that buoyancy-driven convection dominates post-shock turbulence in our simulations. In support of this inference, we present four major results. First, the convective fluxes and kinetic energies in the neutrino-heated region are consistent with expectations of buoyancy-driven convection. Second, the convective flux is positive where buoyancy actively drives convection, and the radial and tangential components of the kinetic energy are in rough equipartition (i.e., K{sub r} {approx} K{sub {theta}} + K{sub {phi}}). Both results are natural consequences of buoyancy-driven convection, and are commonly observed in simulations of convection. Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective luminosity and turbulent dissipation scale with the driving neutrino power. In all, these four results suggest that in neutrino-driven explosions, the multi-dimensional motions are consistent with neutrino-driven convection.

  18. Evolution of moisture convergence in a mesoscale convective complex

    E-Print Network [OSTI]

    Bercherer, John Phillip

    1990-01-01T23:59:59.000Z

    Committee: Dr. Keuneth C. Brundidge Two separate Mesoscale Convective Complexes (MCCs) were investigated to determine if a characteristic surface moisture convergence (MC) signature existed on the mesoscale during their lifecycle. The first storm (Case 1... convergence, a bandpass filtering technique was utilized. It was found that MC could identify the general area of initial thunderstorm activity 2 h prior to its development for both cases. During the initial development stage of Case 1, advection...

  19. AERIAL MEASUREMENTS OF CONVECTION CELL ELEMENTS IN HEATED LAKES

    SciTech Connect (OSTI)

    Villa-Aleman, E; Saleem Salaymeh, S; Timothy Brown, T; Alfred Garrett, A; Malcolm Pendergast, M; Linda Nichols, L

    2007-12-19T23:59:59.000Z

    Power plant-heated lakes are characterized by a temperature gradient in the thermal plume originating at the discharge of the power plant and terminating at the water intake. The maximum water temperature discharged by the power plant into the lake depends on the power generated at the facility and environmental regulations on the temperature of the lake. Besides the observed thermal plume, cloud-like thermal cells (convection cell elements) are also observed on the water surface. The size, shape and temperature of the convection cell elements depends on several parameters such as the lake water temperature, wind speed, surfactants and the depth of the thermocline. The Savannah River National Laboratory (SRNL) and Clemson University are collaborating to determine the applicability of laboratory empirical correlations between surface heat flux and thermal convection intensity. Laboratory experiments at Clemson University have demonstrated a simple relationship between the surface heat flux and the standard deviation of temperature fluctuations. Similar results were observed in the aerial thermal imagery SRNL collected at different locations along the thermal plume and at different elevations. SRNL will present evidence that the results at Clemson University are applicable to cooling lakes.

  20. Extended range chemical sensing apparatus

    DOE Patents [OSTI]

    Hughes, Robert C. (Albuquerque, NM); Schubert, W. Kent (Albuquerque, NM)

    1994-01-01T23:59:59.000Z

    An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.

  1. Extended range chemical sensing apparatus

    DOE Patents [OSTI]

    Hughes, R.C.; Schubert, W.K.

    1994-01-18T23:59:59.000Z

    An apparatus is described for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy. 6 figures.

  2. SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY

    SciTech Connect (OSTI)

    Zhang Chunguang; Deng Licai [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xiong Darun [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Christensen-Dalsgaard, Jorgen, E-mail: cgzhang@nao.cas.cn [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)

    2012-11-01T23:59:59.000Z

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  3. How might a statistical cloud scheme be coupled to a mass-flux convection scheme?

    SciTech Connect (OSTI)

    Klein, Stephen A.; Pincus, Robert; Hannay, Cecile; Xu, Kuan-man

    2004-09-27T23:59:59.000Z

    The coupling of statistical cloud schemes with mass-flux convection schemes is addressed. Source terms representing the impact of convection are derived within the framework of prognostic equations for the width and asymmetry of the probability distribution function of total water mixing ratio. The accuracy of these source terms is quantified by examining output from a cloud resolving model simulation of deep convection. Practical suggestions for inclusion of these source terms in large-scale models are offered.

  4. Natural convection in high heat flux tanks at the Hanford Waste Site / [by] Mark van der Helm and Mujid S. Kazimi

    E-Print Network [OSTI]

    Van der Helm, Mark Johan, 1972-

    1996-01-01T23:59:59.000Z

    A study was carried out on the potential for natural convection and the effect of natural convection in a High Heat Flux Tank, Tank 241-C-106, at the Hanford Reservation. To determine the existence of natural convection, ...

  5. Water Vapor Turbulence Profiles in Stationary Continental Convective Mixed Layers

    SciTech Connect (OSTI)

    Turner, D. D.; Wulfmeyer, Volker; Berg, Larry K.; Schween, Jan

    2014-10-08T23:59:59.000Z

    The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program’s Raman lidar at the ARM Southern Great Plains (SGP) site in north-central Oklahoma has collected water vapor mixing ratio (q) profile data more than 90% of the time since October 2004. Three hundred (300) cases were identified where the convective boundary layer was quasi-stationary and well-mixed for a 2-hour period, and q mean, variance, third order moment, and skewness profiles were derived from the 10-s, 75-m resolution data. These cases span the entire calendar year, and demonstrate that the q variance profiles at the mixed layer (ML) top changes seasonally, but is more related to the gradient of q across the interfacial layer. The q variance at the top of the ML shows only weak correlations (r < 0.3) with sensible heat flux, Deardorff convective velocity scale, and turbulence kinetic energy measured at the surface. The median q skewness profile is most negative at 0.85 zi, zero at approximately zi, and positive above zi, where zi is the depth of the convective ML. The spread in the q skewness profiles is smallest between 0.95 zi and zi. The q skewness at altitudes between 0.6 zi and 1.2 zi is correlated with the magnitude of the q variance at zi, with increasingly negative values of skewness observed lower down in the ML as the variance at zi increases, suggesting that in cases with larger variance at zi there is deeper penetration of the warm, dry free tropospheric air into the ML.

  6. Convection induced by radiative cooling of a layer of participating medium

    SciTech Connect (OSTI)

    Prasanna, Swaminathan, E-mail: prasannaswam@gmail.com [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France)] [Laboratoire EM2C, CNRS UPR 288 92295, Chatenay-Malabry, France and Ecole Centrale Paris, Grande Voie des Vignes 92295, Chatenay-Malabry (France); Venkateshan, S. P., E-mail: spv@iitm.ac.in [HTTP Laboratory, Department of Mechanical Engineering IIT Madras, Chennai (India)

    2014-05-15T23:59:59.000Z

    Simulations and experiments have been conducted to study the effect of radiative cooling on natural convection in a horizontal layer of a participating medium enclosed between isothermal opaque wall and radiatively transparent wall and exposed to a cold background. The study is of relevance to a nocturnal boundary layer under clear and calm conditions. The focus of the study is to capture the onset of convection caused by radiative cooling. The experiments have been designed to mimic the atmospheric radiative boundary conditions, and hence decoupling convection and radiation boundary conditions. Planck number Pl and optical thickness of the layer ?{sub H} are the two important parameters that govern the interaction between radiation and convection. The radiation-convection coupling is a strong function of length scale. Convection sets up within first few seconds for all the experiments. Strong plume like convection is observed for the experimental conditions used in the present study. Both simulations and experiments confirm that radiative cooling increases substantially with decrease in emissivity of the bottom wall. Radiative cooling is strongly influenced by the nongray nature of the participating medium, especially when strong emission from the medium escapes to space, in the window region of the atmosphere. Accurate representation of radiative properties is critical. Linear stability analysis of onset of convection indicates that radiation stabilizes convection as Pl decreases. The observations are similar to the case of Rayleigh Bénard convection in a radiating gas. However, for both experimental and numerical conditions, the observed Rayleigh numbers are much greater than the critical Rayleigh number. To conclude, the role of radiation is to drive and sustain convection in the unstable layer.

  7. Generation of large-scale winds in horizontally anisotropic convection

    E-Print Network [OSTI]

    von Hardenberg, J; Provenzale, A; Spiegel, E A

    2015-01-01T23:59:59.000Z

    We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.

  8. Redistribution of trace chemical species by a small convective cloud

    SciTech Connect (OSTI)

    Stith, J.L.; Alkezweeny, A.J.; Pleim, J.E.; Ching, J.K.S.

    1993-01-01T23:59:59.000Z

    The paper describes a new experiment with a SF6 tracer to determine the mixing history of a small region of cloud-base air. In situ measurements of the SF6 are made to follow the region and simultaneous measurements of natural trace gases are used to determine the dilution of the tagged region as it is affected by the cloud. After describing the experimental method, the results from an experiment with a small cumulus, which was ideally suited for the experiment, are explained. The goal of the paper is to better understand how convective clouds redistribute trace constituents (e.g. moisture, trace gases) in the vertical.

  9. SRS reactor control rod cooling without normal forced convection cooling

    SciTech Connect (OSTI)

    Smith, D.C. (SAIC, Albuquerque, NM (United States)); Easterling, T.C. (Westinghouse Savannah River Co., Aiken, SC (United States))

    1993-01-01T23:59:59.000Z

    This paper describes an analytical study of the coolability of the control rods in the Savannah River site (SRS) K production reactor under conditions of loss of normal forced convection cooling. The study was performed as part of the overall safety analysis of the reactor supporting its restart. The analysis addresses the buoyancy-driven boiling flow over the control rods that occurs when forced cooling is lost. The objective of the study was to demonstrate that the control rods will remain cooled (i.e., no melting) at powers representative of those anticipated for restart of the reactor.

  10. A numerical study of convection with an ambient wind field

    E-Print Network [OSTI]

    Cottrell, Kit Garfield

    1970-01-01T23:59:59.000Z

    equations in ehe same order as in (8. 16)-(8. 19). ? TEB = TEB1 + TEB2 at ? TEC = TEC1 + TEC2 a at ? NEB = MEB1 + NEB2 a ae ? NEC = MEC1 + NEC2 + MEC3 + HECT a at TEB and TEC are the thermal energies for the basic and con- vective flows, respectively...; likewise, MZB and MEC are the mechanical energies for the basic and convective flows. The evaluation of ehese terms at each time step represents the total amount of energy presene in these forms. TEB1 represents a thermal energy transformation...

  11. Gradients of meteorological parameters in convective and nonconvective areas

    E-Print Network [OSTI]

    McCown, Milton Samuel

    1976-01-01T23:59:59.000Z

    . SYNOPTIC CONDITIONS 4. STRATIFICATION OF DATA 5. COMPUTATIONAL PROCEDURES 21 25 a. Gridding of rawinsonde data 25 b. Gradients 26 5'' lp t* 27 RESULTS 29 a. Gradients 29 1) Convective areas 29 2) Nonconvective areas 31 3) Combined areas 33 vi... air turbulence. By using airplane data from over the western United States, Scoggins (1975) has shown that CAT at 300 mb occurred 71% of the time when the magnitude of the vector horizontal wind shear -5 -1 exceeded 4. 5 x 10 sec . The horizontal...

  12. Convection feedbacks in a super-parameterization GCM

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution AndControlling Graphene's ElectronicnewConvection

  13. Range Condition: Key to Sustained Ranch Productivity

    E-Print Network [OSTI]

    McGinty, Allan; White, Larry D.

    2000-04-25T23:59:59.000Z

    Range condition, or a rangeland's "state of health," is an ecological measurement of the current condition of a range. Range condition is evaluated by the plant species composition. This leaflet explains the importance of range condition, how range...

  14. Process for the elimination of waste water produced upon the desulfurization of coking oven gas by means of wash solution containing organic oxygen-carrier, with simultaneous recovery of elemental sulfur

    SciTech Connect (OSTI)

    Diemer, P.; Brake, W.; Dittmer, R.

    1985-04-16T23:59:59.000Z

    A process is disclosed for the elimination of waste water falling out with the desulfurization of coking oven gas by means of an organic oxygen carrier-containing washing solution with simultaneous recovery of elemental sulfur. The waste water is decomposed in a combustion chamber in a reducing atmosphere at temperatures between about 1000/sup 0/ and 1100/sup 0/ C. under such conditions that the mole ratio of H/sub 2/S:SO/sub 2/ in the exhaust gas of the combustion chamber amounts to at least 2:1. Sulfur falling out is separated and the sensible heat of the exhaust gas is utilized for steam generation. The cooled and desulfurized exhaust gas is added to the coking oven gas before the pre-cooling. Sulfur falling out from the washing solution in the oxidizer is separated out and lead into the combustion chamber together with the part of the washing solution discharged as waste water from the washing solution circulation. Preferred embodiments include that the sulfur loading of the waste water can amount to up to about 370 kg sulfur per m/sup 3/ waste water; having the cooling of sulfur-containing exhaust gas leaving the combustion chamber follow in a waste heat boiler and a sulfur condenser heated by pre-heated boiler feed water, from which condenser sulfur is discharged in liquid state.

  15. A Statistical Analysis of Characteristics of Mesoscale Convective System Mountain Initiation Location Clusters in the Arkansas-Red River Basin

    E-Print Network [OSTI]

    Callen, Elisabeth F.

    2012-12-31T23:59:59.000Z

    Mesoscale Convective Systems (MCSs) are the focus of this analysis since it is the convective weather category which is smallest in number but produces the highest amount of precipitation. Being able to forecast these MCSs ...

  16. Pacific Southwest Forest and Range

    E-Print Network [OSTI]

    Standiford, Richard B.

    . MCKETTA is an economist with the College of Forestry, Wildlife, and Range Sciences, University of Idaho has been developed for determining the cost of Fire Management Inputs (FMls)-the direct frreline costs, economic costs, fire economics, suppression costs, Fire Economics Evaluation System (FEES

  17. THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN

    E-Print Network [OSTI]

    Abbett, Bill

    THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN W. P. Abbett Space connection between the convectively unstable layers below the visible surface of the Sun and the overlying application of this numerical model, we present a series of simulations of the quiet Sun in a domain

  18. Linear control and estimation of nonlinear chaotic convection: Harnessing the butterfly effect

    E-Print Network [OSTI]

    Bewley, Thomas

    Linear control and estimation of nonlinear chaotic convection: Harnessing the butterfly effect/robust control theory to a low-order nonlinear chaotic convection problem. Linear control feedback is found before control is applied. Linear estimator feedback is found to be fully effective only when

  19. The Sensitivity of Intraseasonal Variability in the NCAR CCM3 to Changes in Convective Parameterization

    E-Print Network [OSTI]

    Maloney, Eric

    The Sensitivity of Intraseasonal Variability in the NCAR CCM3 to Changes in Convective@atmos.washington.edu. #12;1 Abstract The NCAR CCM3.6 simulation of tropical intraseasonal variability in zonal winds and pre- cipitation can be improved by implementing the McRAS convection scheme of Sud and Walker. The default CCM3

  20. Improving Simulations of Convective Systems from TRMM LBA: Easterly and Westerly Regimes

    E-Print Network [OSTI]

    Rutledge, Steven

    ) experiment in Brazil. These two events epitomized the type of convective systems that formed in two a sheared low-level easterly wind flow. On 23 February 1999, convection developed in weak low-level westerly-scale models. A central objective of the Global Energy and Water-Cycle Experiment (GEWEX) Cloud System Study

  1. Observations, dynamics and predictability of the mesoscale convective vortex event of 10-13 June 2003

    E-Print Network [OSTI]

    Hawblitzel, Daniel Patrick

    2006-08-16T23:59:59.000Z

    with varying resolutions. It is determined that the ability of a forecast model to accurately predict this MCV event is directly related to its ability to simulate convection. It is also shown that the convective-resolving Weather Research and Forecast (WRF...

  2. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01T23:59:59.000Z

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  3. Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model

    SciTech Connect (OSTI)

    Zhang, Guang J [Scripps Institution of Oceanography

    2013-07-29T23:59:59.000Z

    Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

  4. Modelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove

    E-Print Network [OSTI]

    value energy conversions such as heat engine cycles or chemical process to be carried outModelling the convective flow in solar thermal receivers K.C. Yeh; G. Hughes & K. Lovegrove, Canberra AUSTRALIA E-mail: u3370739@anu.edu.au The natural convective flow inside a concentrating solar

  5. Numerical study of natural convection in a vertical porous annulus with discrete heating

    E-Print Network [OSTI]

    Lopez, John M.

    Numerical study of natural convection in a vertical porous annulus with discrete heating M. Sankar online 20 December 2010 Keywords: Natural convection Annulus Discrete heating Porous medium Radii ratio to discrete heating. The outer wall is maintained iso- thermally at a lower temperature, while the top

  6. Observations of prolific transient luminous event production above a mesoscale convective system in Argentina during

    E-Print Network [OSTI]

    Thomas, Jeremy N.

    in Argentina during the Sprite2006 Campaign in Brazil F. T. São Sabbas,1 M. J. Taylor,2 P.D. Pautet,2 M. Bailey convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil, J. Geophys. Res., 115, A

  7. A Climatology of Midlatitude Mesoscale Convective Vortices in the Rapid Update Cycle

    E-Print Network [OSTI]

    Johnson, Richard H.

    A Climatology of Midlatitude Mesoscale Convective Vortices in the Rapid Update Cycle ERIC P. JAMES of mesoscale convective vortices (MCVs) occurring in the state of Oklahoma during the late spring and summer, true MCVs represent only about 20% of the mesoscale relative vorticity maxima detected by the algorithm

  8. Transient luminous events above two mesoscale convective systems: Charge moment change analysis

    E-Print Network [OSTI]

    Rutledge, Steven

    Transient luminous events above two mesoscale convective systems: Charge moment change analysis that were parents of transient luminous events (TLEs; mainly sprites) over two different storms: 9 May (20. A. Rutledge, and D. R. MacGorman (2011), Transient luminous events above two mesoscale convective

  9. THE BASE OF THE CONVECTION ZONE AND THE SOLAR MAGNETIC CYCLE: SEISMIC DETECTION OF THEIR CONNECTION

    E-Print Network [OSTI]

    Monteiro, Mário João

    495 THE BASE OF THE CONVECTION ZONE AND THE SOLAR MAGNETIC CYCLE: SEISMIC DETECTION Unit, School of Mathematical Sciences, Queen Mary & Westfield College, Mile End Road, London El 4NS of the transition at the bot- tom of the solar convection zone, as determined from the periodic signal

  10. PARAMETERS OF THE SOLAR CONVECTION ZONE IN EVOLUTIONARY AND SEISMIC MODELS

    E-Print Network [OSTI]

    PARAMETERS OF THE SOLAR CONVECTION ZONE IN EVOLUTIONARY AND SEISMIC MODELS VLADIMIR A. BATURIN Queen Mary & Westfield College, Mile End Road, London E1 4NS, UK AND SERGEY V. AYUKOV Sternberg of the entropy of the adiabatic part of the solar convection zone are compared. Key words: solar physics

  11. Global Gevrey Regularity for the B'enard Convection in Porous Medium with Zero

    E-Print Network [OSTI]

    Global Gevrey Regularity for the B'enard Convection in Porous Medium with Zero Darcy­Prandtl Number for the three­dimensional B'enard convection model in porous medium with zero Darcy­Prandtl number using system for energy conservation, enhancing recovery of oil by thermal methods, assessing risks for nuclear

  12. Simulated Convective Invigoration Processes at Trade Wind Cumulus Cold Pool ZHUJUN LI AND PAQUITA ZUIDEMA

    E-Print Network [OSTI]

    Zuidema, Paquita

    convection and cold pools using a nested­Weather Research and Fore- casting Model simulation of 19 January ratio drops in simulated cold pools fall within the envelope of observed cases, and the wind enhancement pools invigorating convection at their downwind boundary and suppressing thermals in- side the stable

  13. A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers

    E-Print Network [OSTI]

    Fournier, Alexandre

    A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers Abstract We present a Fourier-spectral element approach for modeling thermal convection in a rotating, Spectral Methods for Axisymmetric Domains, Gauthier-Villars, Paris, 1999], a Fourier expansion of the field

  14. Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth

    E-Print Network [OSTI]

    Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth C, in particular, on its variation with the wavelength of convection. The heat transfer strongly depends in Earth's mantle can significantly reduce the efficiency of heat transfer. The likely variations

  15. EulerianEulerian two-phase numerical simulation of nanofluid laminar forced convection in a microchannel

    E-Print Network [OSTI]

    Harting, Jens

    Eulerian­Eulerian two-phase numerical simulation of nanofluid laminar forced convection August 2010 Accepted 5 August 2010 Keywords: Nanofluid Microchannel Two-phase Laminar Heat transfer a b s t r a c t In this paper, laminar forced convection heat transfer of a copper­water nanofluid inside

  16. Dielectrophoretic Rayleigh-Benard convection under microgravity conditions H. N. Yoshikawa,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    conditions. A thermo-electric coupling resulting from the thermal variation of the electric permittivity of the fluid produces the dielectrophoretic (DEP) body force, which can be regarded as thermal buoyancy due of the GL equation are comparable with those for the RB convection. The heat transfer in the DEP convection

  17. Kinetics of the clay roofing tile convection drying

    SciTech Connect (OSTI)

    Thomas, S. (Univ. of Osijek (Croatia). Faculty of Food Technology); Skansi, D. (Univ. of Zagreb (Croatia). Faculty of Chemical Engineering and Technology); Sokele, M. (Croatian Post and Telecommunications, Zagreb (Croatia). Telecommunications Center)

    1993-01-01T23:59:59.000Z

    Kinetics of the convection drying process of flat tile has been investigated experimentally in an industrial tunnel dryer. Several velocities of wet tile movement through the dryer were tested to obtain maximum allowable drying rate curve. As there are various models to describe the kinetics of convection drying, finding a model that would fairly well approximate the kinetics of the whole drying process was part of the research. Especially the polynomial and exponential models were tested. It was found that exponential model of the type: B(t) = (a[minus]B[sub e])[center dot]EXP([minus]bt[sup 2])+B[sub e], ([minus]dB(t)/dt) = 2bt(B(t)[minus]B[sub e]) significantly correlates the kinetics of the whole tile drying process. Applying the maximum allowable drying rate curve obtained for flat tile in the first period of drying, a grapho-analytic model for the optimal conducting of the process has been developed.

  18. A Multiscale Dynamo Model Driven by Quasi-geostrophic Convection

    E-Print Network [OSTI]

    Calkins, Michael A; Tobias, Steven M; Aurnou, Jonathan M

    2015-01-01T23:59:59.000Z

    A convection-driven multiscale dynamo model is developed for the plane layer geometry in the limit of low Rossby number. The small-scale fluctuating dynamics are described by a magnetically-modified quasi-geostrophic equation set, and the large-scale mean dynamics are governed by a diagnostic thermal wind balance. The model utilizes three timescales that respectively characterize the convective timescale, the large-scale magnetic diffusion timescale, and the large-scale thermal diffusion timescale. Distinct equations are derived for the cases of order one and low magnetic Prandtl number. It is shown that the low magnetic Prandtl number model is characterized by a magnetic to kinetic energy ratio that is asymptotically large, with ohmic dissipation dominating viscous dissipation on the large-scales. For the order one magnetic Prandtl number model the magnetic and kinetic energies are equipartitioned and both ohmic and viscous dissipation are weak on the large-scales; large-scale ohmic dissipation occurs in thi...

  19. Particle filter based on thermophoretic deposition from natural convection flow

    SciTech Connect (OSTI)

    Sasse, A.G.B.M.; Nazaroff, W.W. (Univ. of California, Berkeley, CA (United States)); Gadgil, A.J. (Lawrence Berkeley Lab., CA (United States))

    1994-04-01T23:59:59.000Z

    We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.

  20. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    SciTech Connect (OSTI)

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19T23:59:59.000Z

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  1. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  2. Numerical analysis of heat transfer by conduction and natural convection in loose-fill fiberglass insulation--effects of convection on thermal performance

    SciTech Connect (OSTI)

    Delmas, A.A.; Wilkes, K.E.

    1992-04-01T23:59:59.000Z

    A two-dimensional code for solving equations of convective heat transfer in porous media is used to analyze heat transfer by conduction and convection in the attic insulation configuration. The particular cases treated correspond to loose-fill fiberglass insulation, which is characterized by high porosity and air permeability. The effects of natural convection on the thermal performance of the insulation are analyzed for various densities, permeabilities, and thicknesses of insulation. With convection increasing the total heat transfer through the insulation, the thermal resistance was found to decrease as the temperature difference across the insulating material increases. The predicted results for the thermal resistance are compared with data obtained in the large-scale climate simulator at the Roof Research Center using the attic test module, where the same phenomenon has already been observed. The way the wood joists within the insulation influence the start of convection is studied for differing thermophysical and dynamic properties of the insulating material. The presence of wood joists induces convection at a lower temperature difference.

  3. Charge transfer and in-cloud structure of large-charge-moment positive lightning strokes in a mesoscale convective system

    E-Print Network [OSTI]

    Cummer, Steven A.

    in a mesoscale convective system Gaopeng Lu,1 Steven A. Cummer,1 Jingbo Li,1 Feng Han,1 Richard J. Blakeslee,2 positive cloud-to-ground (+CG) strokes in a mesoscale convective system. Although no high altitude images of large-charge-moment positive lightning strokes in a mesoscale convective system, Geophys. Res. Lett., 36

  4. Magnetospheric Convection The large-scale flow of rarefied plasma in the Earth's magnetosphere "is quite analogous to

    E-Print Network [OSTI]

    Michigan, University of

    quite analogous to thermal convection" (Gold, 1959); therefore, the term "convection" is commonly used of geomagnetic field lines in the crossed E and B fields. By analogy with the thermal convection in a non in the magnetosheath: a region between the bow shock and the magnetopause. A similar flow pattern is formed

  5. Range gated strip proximity sensor

    DOE Patents [OSTI]

    McEwan, T.E.

    1996-12-03T23:59:59.000Z

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

  6. Range gated strip proximity sensor

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1996-01-01T23:59:59.000Z

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

  7. Extended-range tiltable micromirror

    DOE Patents [OSTI]

    Allen, James J. (Albuquerque, NM); Wiens, Gloria J. (Newberry, FL); Bronson, Jessica R. (Gainesville, FL)

    2009-05-05T23:59:59.000Z

    A tiltable micromirror device is disclosed in which a micromirror is suspended by a progressive linkage with an electrostatic actuator (e.g. a vertical comb actuator or a capacitive plate electrostatic actuator) being located beneath the micromirror. The progressive linkage includes a pair of torsion springs which are connected together to operate similar to a four-bar linkage with spring joints. The progressive linkage provides a non-linear spring constant which can allow the micromirror to be tilted at any angle within its range substantially free from any electrostatic instability or hysteretic behavior.

  8. Range Fuels | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit with form History Facebook iconQuito,Jump to:Radiant ElectricRamkyRange Fuels

  9. Experimental Investigation of Natural Convection in Trombe Wall Systems 

    E-Print Network [OSTI]

    Chen, B.; Zhao, J.; Chen, C.; Zhuang, Z.

    2006-01-01T23:59:59.000Z

    :0010:0011:0012:0013:0014:00 15:0016:0017:00 5 10 15 20 25 30 35 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 11/21 Solar radiant intensity[kW/m 2 ] Temperature[ ? ] Time Tr Tfu Twi Ta ------- I Fig. 2 Daily variation of Tr, Tfu, Twi , Ta , I and ? f... regarded that Gr~109 -3?Pr ?10 3? is the transition criterion as the natural convection flow from laminar to turbulent [12]. Experimental data from four sunny days (11.20, 11.21, 11.27, 11.28) with normal thermo-circulation (9:00-16:00) is utilized...

  10. Operating temperatures for a convectively cooled recessed incandescent light fixture

    SciTech Connect (OSTI)

    Yarbrough, D.W.; Toor, I.

    1980-12-01T23:59:59.000Z

    Test results are given for the operation of a recessed incandescent light fixture intended for residential use. The fixture is labeled for use in direct contact with attic thermal insulation. Temperature control of the powered fixture is provided by convective heat transfer from the ceiling side of the fixture. The fixture was operated at power levels up to two times the rated power of 75 watts and under thermal insulations up to R-40. In all operating configurations tested the fixture surface in contact with attic insulation was found to be less than 175/sup 0/C. The observed surface temperatures are judged to be safe for operation in contact with loose-fill or batt-type insulations. It was observed that the power leads inside one fixture configuration are exposed to temperatures as high as 168/sup 0/C. The electrical insulation could, therefore, have a limited life. The properties of the internal fixture wiring were not, however, studied in detail.

  11. Apparatus for production of synthesis gas using convective reforming

    SciTech Connect (OSTI)

    Karafian, M.; Tsang, I.C.

    1991-04-09T23:59:59.000Z

    This patent describes a system for the steam reforming of hydrocarbons into a hydrogen-rich gas. It comprises a convective reformer device having indirect heat exchange means for partially reforming a feed mixture of hydrocarbons and steam; a steam reforming furnace having a radiant section, reforming tubes in the radiant section, and means for producing radiant heat for the further reforming of the partially reformed effluent; an auto-thermal reformer for fully reforming the effluent; conduit means for passing the partially reformed effluent; conduit means for passing the effluent; and conduit means for passing the fully reformed effluent to supply the heat of reaction for the partial reformation of the hydrocarbon-steam feed mixture.

  12. Stability of sunspots to convective motions. I. Adiabatic instability

    SciTech Connect (OSTI)

    Moreno-Insertis, F.; Spruit, H.C. (Instituto de Astrofisica de Canarias, La Laguna (Spain); Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.))

    1989-07-01T23:59:59.000Z

    For determining the adiabatic stability of a uniform vertical field in an arbitrary stratification it is sufficient to consider the limit of infinitesimal horizontal wavelength. It is shown how the behavior of the instability can be estimated qualitatively from the dependence of the equipartition field strength on depth. Modes are calculated numerically for analytic stratification models and for a detailed sunspot stratification, including the effects of partial ionization. It is concluded that for the observed field strengths of umbrae the stratification is indeed unstable, with a growth time of about 18 minutes. The unstable eigenfunctions have a maximum at about 2300 km below the surface of the umbra and are about 3900 km deep. Deeper layers may also be unstable depending on unknown details of the stratification. A connection between fluting instability and convective instability is noted. 37 refs.

  13. TURBULENT CONVECTION IN STELLAR INTERIORS. III. MEAN-FIELD ANALYSIS AND STRATIFICATION EFFECTS

    SciTech Connect (OSTI)

    Viallet, Maxime [Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); Meakin, Casey; Mocak, Miroslav [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Arnett, David [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2013-05-20T23:59:59.000Z

    We present three-dimensional implicit large eddy simulations of the turbulent convection in the envelope of a 5 M{sub Sun} red giant star and in the oxygen-burning shell of a 23 M{sub Sun} supernova progenitor. The numerical models are analyzed in the framework of one-dimensional Reynolds-Averaged Navier-Stokes equations. The effects of pressure fluctuations are more important in the red giant model, owing to larger stratification of the convective zone. We show how this impacts different terms in the mean-field equations. We clarify the driving sources of kinetic energy, and show that the rate of turbulent dissipation is comparable to the convective luminosity. Although our flows have low Mach numbers and are nearly adiabatic, our analysis is general and can be applied to photospheric convection as well. The robustness of our analysis of turbulent convection is supported by the insensitivity of the mean-field balances to linear mesh resolution. We find robust results for the turbulent convection zone and the stable layers in the oxygen-burning shell model, and robust results everywhere in the red giant model, but the mean fields are not well converged in the narrow boundary regions (which contain steep gradients) in the oxygen-burning shell model. This last result illustrates the importance of unresolved physics at the convective boundary, which governs the mixing there.

  14. Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xie, Shaocheng; Jensen, Michael P.; Zhang, Yunyan; Giangrande, Scott E.; McCoy, Renata; Zhang, Minghua

    2014-10-27T23:59:59.000Z

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during themore »morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. Sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.« less

  15. Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xie, Shaocheng [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jensen, Michael P. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Zhang, Yunyan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Giangrande, Scott E. [Brookhaven National Laboratory (BNL), Upton, NY (United States); McCoy, Renata [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Zhang, Minghua [Stony Brook Univ., Stony Brook, NY (United States)

    2014-10-27T23:59:59.000Z

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during the morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. Sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.

  16. Transport and deposition of particles in gas turbines: Effects of convection, diffusion, thermophoresis, inertial impaction and coagulation

    SciTech Connect (OSTI)

    Brown, D.P.; Biswas, P.; Rubin, S.G. [Univ. of Cincinnati, OH (United States)

    1994-12-31T23:59:59.000Z

    Aerosols are produced in a large number of industrial processes over a wide range of sizes. Of particular importance is deposition of coal and oil combustion aerosols in turbines. A model coupling the transport and the dynamics of aerosols to flow characteristics in gas turbines is presented. An order of magnitude analysis is carried out based on typical operational conditions for coal and oil combustion (neglecting coagulation) to determine the relative importance of various mechanisms on particle behavior. A scheme is then developed to incorporate a moment model of a log normally distributed aerosol to predict aerosol transport and dynamics in turbine flows. The proposed moment model reflects the contributions from convection, inertia, diffusion and thermophoresis. Aerosol behavior in various laminar 2-D and axisymmetric flows is considered in this study. Results are compared to published work in 1-D and 2-D planar and axisymmetric.

  17. MODELING HEAT TRANSFER IN SPENT FUEL TRANSFER CASK NEUTRON SHIELDS – A CHALLENGING PROBLEM IN NATURAL CONVECTION

    SciTech Connect (OSTI)

    Fort, James A.; Cuta, Judith M.; Bajwa, C.; Baglietto, E.

    2010-07-18T23:59:59.000Z

    In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations; however, both of these solutions take significant computational effort. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.

  18. Effect of surfactant on evaporative heat transfer coefficients in vertical film forced convection

    E-Print Network [OSTI]

    Shah, Basit Husain

    1972-01-01T23:59:59.000Z

    , and control of temperatures of chemical reactions. . Soi1ing may be considered as a special case of convect1on either free or forced. However, the phenomena of boiling heat transfer are considerably more complex than those of convection without phase...), Leppert and Pitts (4), and Rohsenow The two general situations under which bo111ng occurs are: (a) pool bo1ling and (b) forced convection boiling. When the bulk of the 11quid is at the saturation temperature corresponding to the presssure of the liquid...

  19. Mesoscale flows in large aspect ratio simulations of turbulent compressible convection

    E-Print Network [OSTI]

    F. Rincon; F. Lignieres; M. Rieutord

    2006-11-28T23:59:59.000Z

    We present the results of a very large aspect ratio (42.6) numerical simulation of fully compressible turbulent convection in a polytropic atmosphere, and focus on the properties of large-scale flows. Mesoscale patterns dominate the turbulent energy spectrum. We show that these structures, which had already been observed in Boussinesq simulations by Cattaneo et al. (2001), have a genuine convective origin and do not result directly from collective interactions of the smaller scales of the flow, even though their growth is strongly affected by nonlinear transfers. If this result is relevant to the solar photosphere, it suggests that the dominant convective mode below the Sun's surface may be at mesoscales.

  20. Mesoscale environmental models accompanying convection in the Texas HIPLEX region / by Mark Edward Humbert

    E-Print Network [OSTI]

    Humbert, Mark Edward

    1980-01-01T23:59:59.000Z

    with convection is upward motion at all levels with a maximum value just prior to max1mum convect1ve intensity. Days without convection showed a cont1nual vertical turbulent m1xing of moisture from a shallow boundary layer to the 700 mb level. Lack... of 4 g kg 1 are observed. The moisture content increases at the 22 Post Big Spring Midland Robert Lee 4 500 mb cn 0 O m 8 L. cn 6 x 4 2 700 mb . . ~ ''. ~' . ~ / r 12 10 850 mb 15 18 21 00 03 Time (GNT hours) Fig. 9. Time profiles...

  1. Wide-range voltage modulation

    SciTech Connect (OSTI)

    Rust, K.R.; Wilson, J.M.

    1992-06-01T23:59:59.000Z

    The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

  2. Deep convection and brine rejection in the Japan Sea Lynne D. Talley

    E-Print Network [OSTI]

    Talley, Lynne D.

    ventilation occurs in only a very few regions, generally in confined patches associated with local cyclonic (Figure 1) to these small groups of deep convection sites and regions withdeep``ventilation

  3. Simulation of Mixed Convection Flow in a Room with a Two-Layer Turbulence Model

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    ; displacement ventilation; office rooms. Nomenclature Ary local Archimedes number, 2 /UTyg n C Contaminant used to predict the mixed convection by displacement ventilation in an office. The computed results

  4. STUDY OF MHD MIXED CONVECTION IN THE DCLL BLANKET SMOLENTSEV Sergey1

    E-Print Network [OSTI]

    Abdou, Mohamed

    , and ABDOU Mohamed3 1 University of California, Los Angeles, USA, sergey@fusion.ucla.edu 2 Laboratoire SIMAP, abdou@fusion.ucla.edu Abstract: Magnetohydrodynamic mixed convection associated with a non

  5. Study of formation and convective transport of aerosols using optical diagnostic technique

    E-Print Network [OSTI]

    Kim, Tae-Kyun

    2004-09-30T23:59:59.000Z

    . Part II investigates the characteristics of convective transport behavior of solid particles in virtual impactor (VI). The objective of part I is to establish correlations which offer predictions on atomized particle size of HTFs which are widely...

  6. An Intraseasonal Oscillation Composite Lifecycle in the NCAR CCM3.6 with Modified Convection

    E-Print Network [OSTI]

    Maloney, Eric

    An Intraseasonal Oscillation Composite Lifecycle in the NCAR CCM3.6 with Modified Convection Eric D, 80307­3000, maloney@ucar.edu #12; 1 Abstract The NCAR CCM3.6 with microphysics of clouds with relaxed

  7. An Intraseasonal Oscillation Composite Lifecycle in the NCAR CCM3.6 with Modified Convection

    E-Print Network [OSTI]

    Maloney, Eric

    An Intraseasonal Oscillation Composite Lifecycle in the NCAR CCM3.6 with Modified Convection Eric D, 80307-3000, maloney@ucar.edu #12;1 Abstract The NCAR CCM3.6 with microphysics of clouds with relaxed

  8. Convective structure in rapidly intensifying tropical cyclones as depicted by passive microwave measurements

    E-Print Network [OSTI]

    Nesbitt, Steve

    include: mesovorticies [Nolan and Montgomery, 2002], convective asymmetries [Braun et al., 2006], and vortical hot towers (VHTs) under high wind shear [Molinari and Vollaro, 2010]. Conversely, RI has been

  9. A visualization comparison of convective flow boiling heat transfer augmentation devices

    E-Print Network [OSTI]

    Lundy, Brian Franklin

    1998-01-01T23:59:59.000Z

    The qualitative effects of inset-table heat transfer phics. augmentation devices on vertical in-tube convective flow boiling flow regimes, transition mechanisms, and heat transfer are presented in this study. Three twisted tapes with twist ratios...

  10. A climatology of springtime convection systems over the Northwest Gulf of Mexico and adjacent coasts

    E-Print Network [OSTI]

    Hashem, Magda Sami

    1996-01-01T23:59:59.000Z

    A Springtime (March 15-June 15) climatology of Mesoscale Convective Systems (MCS) has been established on the basis of satellite imagery and radar reflectivities over the Northwest Gulf of Mexico and adjacent coastal areas during 1985...

  11. TACKLEY ET AL.:THERMO-CHEMICAL PHILOSOPHY Numerical and laboratory studies of mantle convection: Philosophy,

    E-Print Network [OSTI]

    Tackley, Paul J.

    TACKLEY ET AL.:THERMO-CHEMICAL PHILOSOPHY 1 Numerical and laboratory studies of mantle convection: Philosophy, accomplishments and thermo-chemical structure and evolution Paul J. Tackley Department of Earth

  12. Radar, satellite, and lightning characteristics of select mesoscale convective systems in Texas

    E-Print Network [OSTI]

    Toracinta, Ernest Richard

    1995-01-01T23:59:59.000Z

    , the observation of high negative flash counts coincident with convective cores having small reflectivity lapse rates in the mixed phase region is consistent with the presence of large ice particles aloft. Positive CG flashes were mostly located in low reflectivity...

  13. Influence of Induced natural convection on laser propagation : analysis and interferometric visualization

    E-Print Network [OSTI]

    Bhakta, Aditya (Aditya S.)

    2010-01-01T23:59:59.000Z

    This thesis analyzes the influence of a self-induced natural convection flow on the propagation of a high energy laser beam. The two configurations considered are of a vertical laser beam (propagation direction opposite ...

  14. Convective cloud and rainfall processes over the Maritime Continent : simulation and analysis of the diurnal cycle

    E-Print Network [OSTI]

    Gianotti, Rebecca L. (Rebecca Louise)

    2013-01-01T23:59:59.000Z

    The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global ...

  15. Convective variability associated with a mesoscale vortex in a midlatitude squall line system

    E-Print Network [OSTI]

    Hristova-Veleva, Svetla M.

    1994-01-01T23:59:59.000Z

    The relationship between the kinematic structure of the convective line and the mesoscale stortn-relative flow associated with an embedded mesovortex in the trailing stratiform region of the 28 May 1985 squall line system is examined using Doppler...

  16. Thermal perturbations caused by large impacts and consequences for mantle convection

    E-Print Network [OSTI]

    Watters, W. A.

    We examine the effects of thermal perturbations on a convecting layer of incompressible fluid with uniform viscosity in the limit of infinite Prandtl number, for two upper boundary conditions (free- and no-slip) and heat ...

  17. A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma

    E-Print Network [OSTI]

    Ohta, Shigemi

    A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma Sciences Division, Argonne National Laboratory, Argonne, Illinois # University of Oklahoma, Norman, Oklahoma @ Bureau of Meteorology, Melbourne, Victoria, Australia & Cooperative Institute for Research

  18. Passive microwave observations of mesoscale convective systems over the tropical Pacific Ocean

    E-Print Network [OSTI]

    McGaughey, Gary Rae

    1994-01-01T23:59:59.000Z

    This paper presents high resolution passive microwave measurements obtained in the western Pacific warm pool region. These measurements represent the first comprehensive observations of convection over the tropical oceans, and were obtained from...

  19. Convective Heat Transfer Enhancement in Nanofluids: Real Anomaly or Analysis Artifact?

    E-Print Network [OSTI]

    Prabhat, Naveen

    The nanofluid literature contains many claims of anomalous convective heat transfer enhancement in both turbulent and laminar flow. To put such claims to the test, we have performed a critical detailed analysis of the ...

  20. Experimental Investigation of Forced Convection Heat Transfer of Nanofluids in a Microchannel using Temperature Nanosensors

    E-Print Network [OSTI]

    Yu, Jiwon 1982-

    2012-12-03T23:59:59.000Z

    Experiments were performed to study forced convective heat transfer of de-ionized water (DI water) and aqueous nanofluids flowing in a microchannel. An array of temperature nanosensors, called “Thin Film Thermocouples (TFT)”, was utilized...

  1. Patterns of convection in rotating spherical R Simitev and F H Busse

    E-Print Network [OSTI]

    Simitev, Radostin D

    Patterns of convection in rotating spherical shells R Simitev and F H Busse Institute of Physics of rotating spherical shells. For recent reviews we refer to the papers by Zhang and Busse [23] and Busse [6

  2. Thermal stability of a spherical shell heated by convection and cooled by boiling

    E-Print Network [OSTI]

    Qaim-Maqami, Hassan

    1973-01-01T23:59:59.000Z

    such high heat transfer rates by forced convection would require extremely high veloc- ities with subsequent high pressure dropsy With nuclee, boiling, however, such high heat transfe. rates an be obtained at much smaller velocities. Boiling heat...THERMAL STABILITY OF A. SPHERICAL SHELL HEATED BY CONVECTION AND COOLED BY BOILING A Thesis HASSAN @AIM-MAQAMI Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER...

  3. Pre-convective environmental conditions indicative of non-tornadic severe thunderstorm winds over Southeast Florida

    E-Print Network [OSTI]

    Wilhelm, Jeffrey Michael

    1987-01-01T23:59:59.000Z

    PRE-CONVECTIVE ENVIRONMENTAL CONDITIONS INDICATIVE OF NON-TORNADIC SEVERE THUNDERSTORM WINDS OVER SOUTHEAST FLORIDA A Thesis by JEFFREY MICHAEL WILHELM Submitted to the Graduate College of Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject: Meteorology PRE-CONVECTIVE ENVIRONMENTAL CONDITIONS INDICATIVE OF NON-TORNADIC SEVERE THUNDERSTORM WINDS OVER SOUTHEAST FLORIDA A Thesis by JEFFREY MICHAEL WILHELM Approved...

  4. Nighttime atmospheric stability changes and their effects on the temporal intensity of a mesoscale convective complex

    E-Print Network [OSTI]

    Hovis, Jeffrey Scott

    1988-01-01T23:59:59.000Z

    NIGHTTIME ATMOSPHERIC STABILITY CHANGES AND THEIR EFFECTS ON THE TEMPORAL INTENSITY OF A MESOSCALE CONVECTIVE COMPLEX A Thesis JEFFREY SCOTT HOVIS Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1988 Major Subject: Meteorology NIGHTTIME ATMOSPHERIC STABILITY CHANGES AND THEIR EFFECTS ON THE TEMPORAL INTENSITY OF A MESOSCALE CONVECTIVE COMPLEX A Thesis JEFFREY SCOTT HOVIS Approved as to style...

  5. Experimental and numerical study of laminar forced convection heat transfer for a dimpled heat sink 

    E-Print Network [OSTI]

    Park, Do Seo

    2009-05-15T23:59:59.000Z

    EXPERIMENTAL AND NUMERICAL STUDY OF LAMINAR FORCED CONVECTION HEAT TRANSFER FOR A DIMPLED HEAT SINK A Thesis by DO SEO PARK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 2007 Major Subject: Mechanical Engineering EXPERIMENTAL AND NUMERICAL STUDY OF LAMINAR FORCED CONVECTION HEAT TRANSFER FOR A DIMPLED HEAT SINK A Thesis by DO SEO PARK...

  6. Respective roles of shallow convection and stratiform rainfall on the simulation of Madden-Julian Oscillation.

    SciTech Connect (OSTI)

    Fu, Joshua Xiouhua [IPRC/SOEST/UH; Wang, Bin [IPRC& DM/SOEST/UH; Yeh, Hsi-Chyi

    2010-03-15T23:59:59.000Z

    Respective Roles of Shallow Convection and Stratiform Rainfall on the Simulation of Madden Julian Oscillation Joshua Xiouhua Fu IPRC, SOEST, University of Hawaii The IPRC/UH Hybrid-coupled GCM (HcGCM), which combined ECHAM-4 AGCM with UH intermediate ocean model, produces robust Tropical Intra-Seasonal Oscillations including the boreal-winter MJO and boreal-summer Monsoon Intra-Seasonal Oscillation. In this study, two sets of sensitivity experiments (i.e., short-term retrospective forecast of one MJO event observed during TOGA COARE and long-term free integrations) have been carried out to understand the respective roles of shallow-convection and stratiform rainfall on the simulations and predictions of the MJO. Major findings are summarized as following: Shallow-convection ahead of MJO deep convection moistens the lower-troposphere and preconditions the movement of the MJO. Present study shows that this process is very important to the eastward propagating speed of the MJO. A significant fraction of stratiform rainfall (~30%; stratiform part vs. total rainfall) is needed for ECHAM-4 to have a robust MJO. The above findings suggest that in addition to deep convection, shallow convection and stratiform rainfall needs to be well represented in conventional GCMs to ensure a robust model MJO.

  7. Effects of Radiative Diffusion on Thin Flux Tubes in Turbulent Solar-like Convection

    E-Print Network [OSTI]

    Weber, Maria A

    2015-01-01T23:59:59.000Z

    We study the combined effects of convection and radiative diffusion on the evolution of thin magnetic flux tubes in the solar interior. Radiative diffusion is the primary supplier of heat to convective motions in the lower convection zone, and it results in a heat input per unit volume of magnetic flux tubes that has been ignored by many previous thin flux tube studies. We use a thin flux tube model subject to convection taken from a rotating spherical shell of turbulent, solar-like convection as described by Weber, Fan, and Miesch (2011, Astrophys. J., 741, 11; 2013, Solar Phys., 287, 239), now taking into account the influence of radiative heating on flux tubes of large-scale active regions. Our simulations show that flux tubes of less than or equal to 60 kG subject to solar-like convective flows do not anchor in the overshoot region, but rather drift upward due to the increased buoyancy of the flux tube earlier in its evolution as a result of the inclusion of radiative diffusion. Flux tubes of magnetic fie...

  8. Inherent safety advantages of carbide fuel systems and technical issues regarding natural convection in LMRs

    SciTech Connect (OSTI)

    Barthold, W.P. [Barthold and Associates, Inc., Albuquerque, NM (United States)

    1984-08-01T23:59:59.000Z

    The scope of work is to summarize inherent safety advantages that are unique to the use of a carbide based fuel system and to summarize the technical issues regarding natural convection flow in LMFBR cores. As discussed in this report, carbide fuel provides the designer with far greater flexibility than oxide fuel. Carbide fuel systems can be designed to eliminate major accident initiators. They turn quantitative advantages into a qualitative advantage. The author proposed to LANL a series of core design and component concepts that would greatly enhance the safety of carbide over oxide systems. This report cites a series of safety advantages which potentially exist for a carbide fuel system. Natural convection issues have not been given much attention in the past. Only during the last few years has this issue been addressed in some detail. Despite claims to the contrary by some of the LMR contractors, the author does not think that the natural convection phenomena is fully understood. Some of the approximations made in natural convection transient analyses have probably a greater impact on calculated transient temperatures than the effects under investigation. Only integral in-pile experimental data and single assembly out-of-pile detailed data are available for comparisons with analytical models and correlations. Especially for derated cores, the natural convection capability of a LMR should be far superior to that of a LWR. The author ranks the natural convection capability of the LMR as the most important inherent safety feature.

  9. Compactification of Patterns by a Singular Convection or Stress

    SciTech Connect (OSTI)

    Rosenau, Philip [School of Mathematical Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

    2007-12-07T23:59:59.000Z

    A wide variety of propagating disturbances in physical systems are described by equations whose solutions lack a sharp propagating front. We demonstrate that presence of particular nonlinearities may induce such fronts. To exemplify this idea, we study both dissipative u{sub t}+{partial_derivative}{sub x}f(u)=u{sub xx} and dispersive u{sub t}+{partial_derivative}{sub x}f(u)+u{sub xxx}=0 patterns, and show that a weakly singular convection f(u)=-u{sup {alpha}}+u{sup m}, 0<{alpha}<1

  10. Radial convection of finite ion temperature, high amplitude plasma blobs

    SciTech Connect (OSTI)

    Wiesenberger, M., E-mail: Matthias.Wiesenberger@uibk.ac.at; Kendl, A. [Institute for Ion Physics and Applied Physics, Association EURATOM-ÖAW, University of Innsbruck, A-6020 Innsbruck (Austria); Madsen, J. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

    2014-09-15T23:59:59.000Z

    We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.

  11. Fingering convection and cloudless models for cool brown dwarf atmospheres

    E-Print Network [OSTI]

    Tremblin, P; Mourier, P; Baraffe, I; Chabrier, G; Drummond, B; Homeier, D; Venot, O

    2015-01-01T23:59:59.000Z

    This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral type T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the photosphere at the L/T transition, but cloudless models fail to reproduce correctly the spectra of T dwarfs, advocating for the addition of more physics, e.g. other types of clouds or internal energy transport mechanisms. We use a one-dimensional (1D) radiative/convective equilibrium code ATMO to investigate this issue. This code includes both equilibrium and out-of-equilibrium chemistry and solves consistently the PT structure. Included opacity sources are H2-H2, H2-He, H2O, CO, CO2, CH4, NH3, K, Na, and TiO, VO if they are present in the atmosphere. We show that the spectra of Y dwarfs can be accurately reproduced with a cloudless model if vertical mixing and NH3 quenching are taken into account. T dwarf spectra still have some reddening in e.g. J - H compared to cloudless mode...

  12. Radar range measurements in the atmosphere.

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2013-02-01T23:59:59.000Z

    The earth's atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

  13. Lead exposure at uncovered outdoor firing ranges

    SciTech Connect (OSTI)

    Goldberg, R.L.; Hicks, A.M.; O'Leary, L.M.; London, S. (University of Southern California School of Medicine, Los Angeles (USA))

    1991-06-01T23:59:59.000Z

    Excessive lead exposure in shooting instructors at indoor firing ranges and covered outdoor firing ranges has been documented. The City of Los Angeles assessed exposure of its full-time shooting instructors at uncovered outdoor ranges via air monitoring and blood lead-level measurements. Results of these tests revealed that significant lead exposure and absorption can occur at outdoor firing ranges. The use of copper-jacketed ammunition may decrease air lead levels and decrease lead absorption by range instructors.

  14. EA-1662: Final Environmental Assessment

    Broader source: Energy.gov [DOE]

    10 CFR Part 430 Energy Conservation Program: EnergyConservation Standards for Certain Consumer Products (Dishwashers, Dehumidifiers, Microwave Ovens, and Electric and Gas Kitchen Ranges and Ovens)

  15. Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation

    SciTech Connect (OSTI)

    Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)

    2014-08-15T23:59:59.000Z

    A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudy–clear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.

  16. Potential Aerosol Indirect Effects on Atmospheric Circulation and Radiative Forcing through Deep Convection

    SciTech Connect (OSTI)

    Fan, Jiwen; Rosenfeld, Daniel; Ding, Yanni; Leung, Lai-Yung R.; Li, Zhanqing

    2012-05-10T23:59:59.000Z

    Aerosol indirect effects, i.e., the interactions of aerosols with clouds by serving as cloud condensation nuclei (CCN) or ice nuclei (IN), constitute the largest uncertainty in climate forcing and projection. Previous IPCC reported aerosol indirect forcing is negative, which does not account for aerosol-convective cloud interactions because the complex processes involved are poorly understood and represented in climate models. Here we report that aerosol indirect effect on deep convective cloud systems can lead to enhanced regional convergence and a strong top-of atmosphere (TOA) warming. Aerosol invigoration effect on convection can result in a strong radiative warming in the atmosphere (+5.6 W m-2) due to strong night-time warming, a lofted latent heating, and a reduced diurnal temperature difference, all of which could remarkably impact regional circulation and modify weather systems. We further elucidated how aerosols change convective intensity, diabatic heating, and regional circulation under different environmental conditions and concluded that wind shear and cloud base temperature play key roles in determining the significance of aerosol invigoration effect for convective systems.

  17. Structure and Evolution of Giant Cells in Global Models of Solar Convection

    E-Print Network [OSTI]

    Mark S. Miesch; Allan Sacha Brun; Marc L. Derosa; Juri Toomre

    2007-07-10T23:59:59.000Z

    The global scales of solar convection are studied through three-dimensional simulations of compressible convection carried out in spherical shells of rotating fluid which extend from the base of the convection zone to within 15 Mm of the photosphere. Such modelling at the highest spatial resolution to date allows study of distinctly turbulent convection, revealing that coherent downflow structures associated with giant cells continue to play a significant role in maintaining the strong differential rotation that is achieved. These giant cells at lower latitudes exhibit prograde propagation relative to the mean zonal flow, or differential rotation, that they establish, and retrograde propagation of more isotropic structures with vortical character at mid and high latitudes. The interstices of the downflow networks often possess strong and compact cyclonic flows. The evolving giant-cell downflow systems can be partly masked by the intense smaller scales of convection driven closer to the surface, yet they are likely to be detectable with the helioseismic probing that is now becoming available. Indeed, the meandering streams and varying cellular subsurface flows revealed by helioseismology must be sampling contributions from the giant cells, yet it is difficult to separate out these signals from those attributed to the faster horizontal flows of supergranulation. To aid in such detection, we use our simulations to describe how the properties of giant cells may be expected to vary with depth, how their patterns evolve in time, and analyze the statistical features of correlations within these complex flow fields.

  18. Aspect ratio dependence of heat transport by turbulent Rayleigh-B\\'{e}nard convection in rectangular cells

    E-Print Network [OSTI]

    Zhou, Quan; Li, Chun-Mei; Zhong, Bao-Chang

    2012-01-01T23:59:59.000Z

    We report high-precision measurements of the Nusselt number $Nu$ as a function of the Rayleigh number $Ra$ in water-filled rectangular Rayleigh-B\\'{e}nard convection cells. The horizontal length $L$ and width $W$ of the cells are 50.0 cm and 15.0 cm, respectively, and the heights $H=49.9$, 25.0, 12.5, 6.9, 3.5, and 2.4 cm, corresponding to the aspect ratios $(\\Gamma_x\\equiv L/H,\\Gamma_y\\equiv W/H)=(1,0.3)$, $(2,0.6)$, $(4,1.2)$, $(7.3,2.2)$, $(14.3,4.3)$, and $(20.8,6.3)$. The measurements were carried out over the Rayleigh number range $6\\times10^5\\lesssim Ra\\lesssim10^{11}$ and the Prandtl number range $5.2\\lesssim Pr\\lesssim7$. Our results show that for rectangular geometry turbulent heat transport is independent of the cells' aspect ratios and hence is insensitive to the nature and structures of the large-scale mean flows of the system. This is slightly different from the observations in cylindrical cells where $Nu$ is found to be in general a decreasing function of $\\Gamma$, at least for $\\Gamma=1$ and l...

  19. Viking Range: Order (2014-CE-23014)

    Broader source: Energy.gov [DOE]

    DOE ordered Viking Range, LLC to pay a $8,000 civil penalty after finding Viking Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.

  20. American Range: Order (2014-CE-23006)

    Broader source: Energy.gov [DOE]

    DOE ordered American Range Corporation to pay a $8,000 civil penalty after finding American Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.

  1. On Cartesian trees and range minimum queries

    E-Print Network [OSTI]

    Demaine, Erik D.

    We present new results on Cartesian trees with applications in range minimum queries and bottleneck edge queries. We introduce a cache-oblivious Cartesian tree for solving the range minimum query problem, a Cartesian tree ...

  2. Range Fuels Commercial-Scale Biorefinery

    Broader source: Energy.gov [DOE]

    The Range Fuels commercial-scale biorefinery will use a variety of feedstocks to create cellulosic ethanol, methanol, and power.

  3. Constructing a Merged Cloud-Precipitation Radar Dataset for Tropical Convective Clouds during the DYNAMO/AMIE Experiment at Addu Atoll

    SciTech Connect (OSTI)

    Feng, Zhe; McFarlane, Sally A.; Schumacher, Courtney; Ellis, Scott; Comstock, Jennifer M.; Bharadwaj, Nitin

    2014-05-16T23:59:59.000Z

    To improve understanding of the convective processes key to the Madden-Julian-Oscillation (MJO) initiation, the Dynamics of the MJO (DYNAMO) and Atmospheric Radiation Measurement MJO Investigation Experiment (AMIE) collected four months of observations from three radars, the S-band Polarization Radar (S-Pol), the C-band Shared Mobile Atmospheric Research & Teaching Radar (SMART-R), and Ka-band Zenith Radar (KAZR) on Addu Atoll in the tropical Indian Ocean. This study compares the measurements from the S-Pol and SMART-R to those from the more sensitive KAZR in order to characterize the hydrometeor detection capabilities of the two scanning precipitation radars. Frequency comparisons for precipitating convective clouds and non-precipitating high clouds agree much better than non-precipitating low clouds for both scanning radars due to issues in ground clutter. On average, SMART-R underestimates convective and high cloud tops by 0.3 to 1.1 km, while S-Pol underestimates cloud tops by less than 0.4 km for these cloud types. S-Pol shows excellent dynamic range in detecting various types of clouds and therefore its data are well suited for characterizing the evolution of the 3D cloud structures, complementing the profiling KAZR measurements. For detecting non-precipitating low clouds and thin cirrus clouds, KAZR remains the most reliable instrument. However, KAZR is attenuated in heavy precipitation and underestimates cloud top height due to rainfall attenuation 4.3% of the time during DYNAMO/AMIE. An empirical method to correct the KAZR cloud top heights is described, and a merged radar dataset is produced to provide improved cloud boundary estimates, microphysics and radiative heating retrievals.

  4. Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations

    E-Print Network [OSTI]

    Salaris, Maurizio

    2015-01-01T23:59:59.000Z

    (abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational properties like radius and effective temperature. The Mixing Length Theory, almost universally used to model the superadiabatic convective layers, contains effectively one free parameter to be calibrated --alpha(ml)-- whose value controls the resulting effective temperature. Here we present the first self-consistent stellar evolution models calculated by employing the atmospheric temperature stratification, Rosseland opacities, and calibrated variable alpha(ml) (dependent on effective temperature and surface gravity) from a large suite of three-dimensional radiation hydrodynamics simulations of stellar convective envelopes and atmospheres for solar stellar composition (Trampedach et al. 2013). From our calculations (with the same composition of the radiation hydrodynamics simulatio...

  5. The Mid-latitude Continental Convective Clouds (MC3E) Experiment Final Campaign Report

    SciTech Connect (OSTI)

    Jensen, Michael [Brookhaven National Laboratory; Kollias, Pavlos [McGill University; Giangrande, Scott

    2014-04-01T23:59:59.000Z

    The Mid-latitude Continental Convective Clouds Experiment (MC3E) took place from April 22 through June 6, 2011, centered at the ARM Southern Great Plains site (http://www.arm.gov/sites/sgp) in northcentral Oklahoma. MC3E was a collaborative effort between the ARM Climate Research Facility and the National Aeronautics and Space Administration’s (NASA’s) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The campaign leveraged the largest ground-based observing infrastructure available in the central United States, including recent upgrades through the American Recovery and Reinvestment Act of 2009, combined with an extensive sounding array, remote sensing and in situ aircraft observations, and additional radar and in situ precipitation instrumentation. The overarching goal of the campaign was to provide a three-dimensional characterization of convective clouds and precipitation for the purpose of improving the representation of convective lifecycle in atmospheric models and the reliability of satellite-based retrievals of precipitation.

  6. Large-scale weakly nonlinear perturbations of convective magnetic dynamos in a rotating layer

    E-Print Network [OSTI]

    Chertovskih, Roman

    2015-01-01T23:59:59.000Z

    We present a new mechanism for generation of large-scale magnetic field by thermal convection which does not involve the alpha-effect. We consider weakly nonlinear perturbations of space-periodic steady convective magnetic dynamos in a rotating layer that were identified in our previous work. The perturbations have a spatial scale in the horizontal direction that is much larger than the period of the perturbed convective magnetohydrodynamic state. Following the formalism of the multiscale stability theory, we have derived the system of amplitude equations governing the evolution of the leading terms in expansion of the perturbations in power series in the scale ratio. This asymptotic analysis is more involved than in the cases considered earlier, because the kernel of the operator of linearisation has zero-mean neutral modes whose origin lies in the spatial invariance of the perturbed regime, the operator reduced on the generalised kernel has two Jordan normal form blocks of size two, and simplifying symmetri...

  7. Development and evaluation of a convection scheme for use in climate models

    SciTech Connect (OSTI)

    Emanuel, K.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Program for Atmospheres, Oceans, and Climate; Zivkovic-Rothman, M. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)] [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

    1999-06-01T23:59:59.000Z

    Cumulus convection is a key process in controlling the water vapor content of the atmosphere, which is in turn the largest feedback mechanism for climate change in global climate models. Yet scant attention has been paid to designing convective representations that attempt to handle water vapor with fidelity, and even less to evaluating their performance. Here the authors attempt to address this deficiency by designing a representation of cumulus convection with close attention paid to convective water fluxes and by subjecting the scheme to rigorous tests using sounding array data. The authors maintain that such tests, in which a single-column model is forced by large-scale processes measured by or inferred from the sounding data, must be carried out over a period at least as long as the radiative-subsidence timescale--about 30 days--governing the water vapor adjustment time. The authors also argue that the observed forcing must be preconditioned to guarantee integral enthalpy conservation, else errors in the single-column prediction may be falsely attributed to convective schemes. Optimization of the new scheme`s parameters is performed using one month of data from the intensive flux array operating during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, with the aid of the adjoint of the linear tangent of the single-column model. Residual root-mean-square errors, after optimization, are about 15% in relative humidity and .8 K in temperature. It is difficult to reject the hypothesis that the residual errors are due to noise in the forcing. Evaluation of the convective scheme is performed using Global Atmospheric Research Program Atlantic Tropical Experiment data. The performance of the scheme is compared to that of a few other schemes used in current climate models. It is also shown that a vertical resolution better than 50 mb in pressure is necessary for accurate prediction of atmospheric water vapor.

  8. Urban and land surface effects on the 30 July 2003 mesoscale convective system event observed in the southern Great Plains

    E-Print Network [OSTI]

    Niyogi, Dev

    Urban and land surface effects on the 30 July 2003 mesoscale convective system event observed/Atmosphere Mesoscale Prediction System (COAMPS 1 ) to investigate the impact of urban and land vegetation processes on the prediction of the mesoscale convective system (MCS) observed on 30 July 2003 in the vicinity of Oklahoma City

  9. Chaotic flow in a 2D natural convection loop with heat flux boundaries William F. Louisos a,b,

    E-Print Network [OSTI]

    Danforth, Chris

    . Examples of natural convection cells occurring in engineering devices include solar water heaters, nu into the system while the upper half is cooled by an equal-but- opposite heat flux out of the system. Water between landmass and an adjacent body of water; mantle convection of the Earth's asthenosphere which

  10. Scaling laws for convection and jet speeds in the giant planets Adam P. Showman a,b,,1

    E-Print Network [OSTI]

    Scaling laws for convection and jet speeds in the giant planets Adam P. Showman a,b,,1 , Yohai in these models, but no previous theories have been advanced to explain these trends. Here, we show using simple arguments that if convective release of potential energy pumps the jets and viscosity damps them, the mean

  11. A Fundamental Study of Convective Mixing of CO2 in Heterogeneous Geologic Media using Surrogate Fluids and Numerical Modeling

    E-Print Network [OSTI]

    of formation heterogeneity on convective mixing. Finite volume based numerical code was developed to capture of Canadian Petroleum Technology, 44(10). - Neufeld, J. A., Hesse M. A., Riaz, A., Hallworth M. A., Tchelepi, H. A., and Huppert H. E., 2010, Convective dissolution of carbon dioxide in saline aquifers, Geophys

  12. Thermal anomaly near the Aigio fault, Gulf of Corinth, Greece, maybe due to convection below the fault

    E-Print Network [OSTI]

    Thermal anomaly near the Aigio fault, Gulf of Corinth, Greece, maybe due to convection below intersecting the active Aigio fault, Corinth Rift, Greece. The heat flow is 53 mW/m2 , indicating of Corinth, Greece, maybe due to convection below the fault, Geophys. Res. Lett., 34, L06314, doi:10

  13. Improvements to simulation of Madden Julian Oscillation due to deep1 convection parameterization modifications in the Community Climate2

    E-Print Network [OSTI]

    Jochum, Markus

    coherent structures, which are43 important features of observed MJOs. The conclusions are supported by two, and small-scale convection (e.g., Blade and Hartmann 1993; Hu and Randall 1995;53 Kemball-Cook and Weare. 1999). A key factor in improving MJO simulation is the convective58 parameterization. Many tests have

  14. October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems

    E-Print Network [OSTI]

    Johnson, Richard H.

    October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale components of tropical mesoscale convective systems. It is found that while the apparent heat source Q1 of mesoscale downdrafts within the mesoscale convective systems. The warming and drying at low levels

  15. Using Digital Cloud Photogrammetry to Characterize the Onset and Transition from Shallow to Deep Convection Over Orography

    E-Print Network [OSTI]

    the entrainment of dry air. Time series of convective development are compared with sounding and surface data of the environment. Surface fluxes of sensible and latent heat, along with the transport of boundary layer air the effect of entrainment on the consumption of convective available potential energy (CAPE) is still

  16. Modeling the coupling between free and forced convection in a vertical permeable slot: implications for the heat

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Modeling the coupling between free and forced convection in a vertical permeable slot numerical study of the coupling between forced and free convective flows has been performed by considering: implications for the heat production of an Enhanced Geothermal System Arnaud Batailléa , Pierre Genthona

  17. Scale/Analytical Analyses of Freezing and Convective Melting with Internal Heat Generation

    SciTech Connect (OSTI)

    Ali S. Siahpush; John Crepeau; Piyush Sabharwall

    2013-07-01T23:59:59.000Z

    Using a scale/analytical analysis approach, we model phase change (melting) for pure materials which generate constant internal heat generation for small Stefan numbers (approximately one). The analysis considers conduction in the solid phase and natural convection, driven by internal heat generation, in the liquid regime. The model is applied for a constant surface temperature boundary condition where the melting temperature is greater than the surface temperature in a cylindrical geometry. The analysis also consider constant heat flux (in a cylindrical geometry).We show the time scales in which conduction and convection heat transfer dominate.

  18. A case study of the low-level jet during an episode of spring convection

    E-Print Network [OSTI]

    Donahoe, Christopher Scott

    1996-01-01T23:59:59.000Z

    A CASE STUDY OF THE LOW-LEVEL JET DURING AN EPISODE OF SPRING CONVECTION A Thesis CHRISTOPHER SCOTT DONAHOE Submitted to the Office of Graduate Studies of Texas AdrM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1996 Major Subject: Meteorology A CASE STUDY OF THE LOW-LEVEL JET DURING AN EPISODE OF SPRING CONVECTION A Thesis by CHRISTOPHER SCOTT DONAHOE Submitted to Texas A&M University in partial ful6llment of the requirements...

  19. Tonopah Test Range capabilities: technical manual

    SciTech Connect (OSTI)

    Manhart, R.L.

    1982-11-01T23:59:59.000Z

    This manual describes Tonopah Test Range (TTR), defines its testing capabilities, and outlines the steps necessary to schedule tests on the Range. Operated by Sandia National Laboratories, TTR is a major test facility for DOE-funded weapon programs. The Range presents an integrated system for ballistic test vehicle tracking and data acquisition. Multiple radars, optical trackers, telemetry stations, a central computer complex, and combined landline/RF communications systems assure full Range coverage for any type of test. Range operations are conducted by a department within Sandia's Field Engineering Directorate. While the overall Range functions as a complete system, it is operationally divided into the Test Measurements, Instrumentation Development, and Range Operations divisions. The primary function of TTR is to support DOE weapons test activities. Management, however, encourages other Government agencies and their contractors to schedule tests on the Range which can make effective use of its capabilities. Information concerning Range use by organizations outside of DOE is presented. Range instrumentation and support facilities are described in detail. This equipment represents the current state-of-the-art and reflects a continuing commitment by TTR management to field the most effective tracking and data acquisition system available.

  20. Advection, Moistening, and Shallow-to-deep Convection Transitions During the Initiation and Propagation of Madden-Julian Oscillation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; Landu, Kiranmayi; Long, Charles N.

    2014-09-11T23:59:59.000Z

    Using observations from the 2011 AMIE/DYNAMO field campaign over the Indian Ocean and a high-resolution regional model simulation, the processes that lead to the rapid shallow-to-deep convection transitions associated with the initiation and eastward propagation of the Madden-Julian Oscillation (MJO) are examined. By tracking the evolution of the depth of several thousand individual model simulated precipitation features, the role of and the processes that control the observed midtropospheric moisture buildup ahead of the detection of deep convection are quantified at large and convection scales. The frequency of shallow-to-deep convection transitions is found to be sensitive to this midlevel moisture and large-scale uplift. This uplift along with the decline of large-scale drying by equator-ward advection causes the moisture buildup leading to the initiation of the MJO. Convection scale moisture variability and uplift, and large-scale zonal advection play secondary roles.

  1. The Environment of Precipitating Shallow Cumulus Convection LOUISE NUIJENS

    E-Print Network [OSTI]

    Siebesma, Pier

    ), with estimates ranging up to 20%. These estimates are based on subsets of TRMM data for which the majority of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California BJORN STEVENS Sciences, University of California, Los Angeles, Los Angeles, California A. PIER SIEBESMA Royal Netherlands

  2. Generation of mesoscale convective structures in tokamak edge plasma

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.; Smolyakov, A. I. [University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2 (Canada)

    2007-10-15T23:59:59.000Z

    It is shown that the interplay of the interchange drive and nonlinear effects of Reynolds stress and inverse cascade of drift wave turbulence select a range of plasma parameters (plasma pressure), for which mesoscale perturbations of a certain transverse length scale become unstable. It is suggested that the blob formation is a result of these mesoscale instabilities.

  3. Viking Range: Proposed Penalty (2014-CE-23014)

    Broader source: Energy.gov [DOE]

    DOE alleged in a Notice of Proposed Civil Penalty that Viking Range, LLC failed to certify cooking products as compliant with the applicable energy conservation standards.

  4. Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle

    E-Print Network [OSTI]

    Lockwood, Mike

    Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle: 1. Persistence of cusp proton aurora K. Throp, M. Lockwood,1 B. S. Lanchester, and S. K employ a numerical model of cusp ion precipitation and proton aurora emission to fit variations

  5. Reverse convection and cusp proton aurora: Cluster, polar and image observation

    E-Print Network [OSTI]

    California at Berkeley, University of

    Reverse convection and cusp proton aurora: Cluster, polar and image observation Q.-G. Zong a,b,*, TT) at Earth. Cusp proton aurora was caused by the leading phase of the CME. Cusp proton aurora generally of the cusp proton aurora shifted about 30° from dawnside to duskside when IMF By changed from À10 to 5 n

  6. Convective Cell Formation in a Z-Pinch Plasma Science and Fusion Center

    E-Print Network [OSTI]

    Convective Cell Formation in a Z-Pinch J. Kesner Plasma Science and Fusion Center Massachusetts Institute of Technology Cambridge, MA 02139 PSFC Report PSFC/JA-02-27 Abstract Closed field line confinement given by Eq. (1). These equations were then applied to a hard core z pinch which can be considered

  7. The Influence of Thermal Convection on Density Segregation in a Vibrated Binary Granular System

    E-Print Network [OSTI]

    Al Hanbali, Ahmad

    of this work strongly imply the possibility that, for an adequately fluidised granular bed, the degree^ole of diffusive behaviour in the segregation of a gran- ular bed in the convective regime. The results on the fluctuation of particle velocities about a mean value [53]. For a granular bed excited by, for instance

  8. Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from forest fires

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from observations show that desert dust and heavy air pollution over East Asia have similar ability to glaciate desert dust, air pollution and smoke from forest fires, Geophys. Res. Lett., 38, L21804, doi:10

  9. EQUILIBRIUM VS. ACTIVATION CONTROL OF LARGE-SCALE VARIATIONS OF TROPICAL DEEP CONVECTION

    E-Print Network [OSTI]

    Mapes, Brian

    convective cloud systems. This essay highlights the distinction between processes which supply moisture separations of the LSVDC problem are reviewed. Scale separation, though rigorous, is artificial, since net cloudiness, are exam- ined as examples. Lower boundary flux enhancements and deep lifting exert both

  10. A case study of boundary layer ventilation by convection and coastal processes

    E-Print Network [OSTI]

    Dacre, Helen

    A case study of boundary layer ventilation by convection and coastal processes H. F. Dacre,1 S. L; published 12 September 2007. [1] It is often assumed that ventilation of the atmospheric boundary layer responsible for ventilation of the atmospheric boundary layer during a nonfrontal day that occurred on 9 May

  11. Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry

    DOE Patents [OSTI]

    Siminovitch, M.

    1998-02-10T23:59:59.000Z

    A novel design is described for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment. 9 figs.

  12. Tropical ozone as an indicator of deep convection Ian Folkins and Christopher Braun

    E-Print Network [OSTI]

    Folkins, Ian

    Tropical ozone as an indicator of deep convection Ian Folkins and Christopher Braun Department] The climatological ozone profile in the tropics is shaped like an ``S,'' with a minimum at the surface, a maximum. These features can be reproduced by a very simple model whose only free parameter is the mean ozone mixing ratio

  13. Convectively Coupled Waves Propagating along an Equatorial ITCZ JULIANA DIAS AND OLIVIER PAULUIS

    E-Print Network [OSTI]

    Pauluis, Olivier M.

    Convectively Coupled Waves Propagating along an Equatorial ITCZ JULIANA DIAS AND OLIVIER PAULUIS waves propagate at the moist gravity wave speed (about 15 m s21 ), whereas for a narrow ITCZ, the propagation speed is comparable to the dry gravity wave (about 50 m s21 ). It is also shown that a Kelvin wave

  14. Convective-Resolving Regional Climate Simulations for the Amazon Basin: Comparison with TRMM Rainfall Data

    E-Print Network [OSTI]

    Kinney, Nichole 1987-

    2012-08-21T23:59:59.000Z

    the Weather Research and Forecasting (WRF) model are computed at 4-km grid spacing, which reasonably resolves most convective systems. Simulations are computed for both the DJF and MAM seasons as averaged over 2005-2008, with a model domain covering...

  15. Adaptive Thermal Management for Portable System Batteries by Forced Convection Cooling

    E-Print Network [OSTI]

    Pedram, Massoud

    Adaptive Thermal Management for Portable System Batteries by Forced Convection Cooling Qing Xie}@elpl.snu.ac.kr Abstract-- Cycle life of a battery largely varies according to the battery operating conditions, especially the battery temperature. In particular, batteries age much faster at high temperature. Extensive experiments

  16. Vertical structure of tropical oceanic convective clouds and its relation to precipitation

    E-Print Network [OSTI]

    Hartmann, Dennis

    data are collocated with precipitation rates from the Advanced Microwave Scanning Radiometer (AMSR high tops that are nearly two km deeper than moderately raining or non- raining high clouds. Rain rate.1029/2007GL032811. 1. Introduction [2] Tropical convection plays an important role in the energy and moisture

  17. Local helioseismology and correlation tracking analysis of surface structures in realistic simulations of solar convection

    E-Print Network [OSTI]

    Dali Georgobiani; Junwei Zhao; Alexander Kosovichev; David Benson; Robert F. Stein; Åke Nordlund

    2007-01-31T23:59:59.000Z

    We apply time-distance helioseismology, local correlation tracking and Fourier spatial-temporal filtering methods to realistic supergranule scale simulations of solar convection and compare the results with high-resolution observations from the SOHO Michelson Doppler Imager (MDI). Our objective is to investigate the surface and sub-surface convective structures and test helioseismic measurements. The size and grid of the computational domain are sufficient to resolve various convective scales from granulation to supergranulation. The spatial velocity spectrum is approximately a power law for scales larger than granules, with a continuous decrease in velocity amplitude with increasing size. Aside from granulation no special scales exist, although a small enhancement in power at supergranulation scales can be seen. We calculate the time-distance diagram for f- and p-modes and show that it is consistent with the SOHO/MDI observations. From the simulation data we calculate travel time maps for surface gravity waves (f-mode). We also apply correlation tracking to the simulated vertical velocity in the photosphere to calculate the corresponding horizontal flows. We compare both of these to the actual large-scale (filtered) simulation velocities. All three methods reveal similar large scale convective patterns and provide an initial test of time-distance methods.

  18. Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice

    E-Print Network [OSTI]

    Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice M.J. McGuinness \\Lambda , H a programme recently set up to directly measure the thermal conductivity of young sea ice. An array of thermistors frozen into first­year Antarctic sea ice provides temperature against depth data, which is fitted

  19. Effect of convective cooling on frictionally excited thermoelastic instability , A. Bendawi

    E-Print Network [OSTI]

    Yi, Yun-Bo

    of temperature/pressure at a given sliding speed or the critical value of the speed above which the system critical sliding velocity. Two representative models for brake and clutch systems are studied. The computational results reveal that the effect of thermal convection on the critical sliding speed is significant

  20. The effect of shear on heat budgets in a simulated Mesoscale Convective System

    E-Print Network [OSTI]

    Shaw, Justin David

    2000-01-01T23:59:59.000Z

    in the lowest 2.5 km varying from 10-25 m s?¹. A fourth simulation was conducted using the weak wind shear profile and incorporating ice microphysics. An analysis domain was produced every two hours for the northern and southern portions of the convective line...

  1. Homogenization of a Conductive, Convective and Radiative Heat Transfer Problem in a Heterogeneous Domain

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -cooled reactor. It is typically made of many prismatic blocks of graphite in which are inserted the nuclear fuel in the homogenization of heat transfer in periodic porous media where the fluid part is made of long thin parallel in the solid part of the domain and by conduction, convection and radiative transfer in the fluid part (the

  2. 1 Spreading and convective dissolution of carbon dioxide in vertically 2 confined, horizontal aquifers

    E-Print Network [OSTI]

    Neufeld, Jerome A.

    1 Spreading and convective dissolution of carbon dioxide in vertically 2 confined, horizontal] Injection of carbon dioxide (CO2) into saline aquifers is a promising tool for reducing 6 anthropogenic CO2 emissions. At reservoir conditions, the injected CO2 is buoyant relative 7 to the ambient groundwater

  3. Spreading and convective dissolution of carbon dioxide in vertically confined, horizontal aquifers

    E-Print Network [OSTI]

    Huppert, Herbert

    Spreading and convective dissolution of carbon dioxide in vertically confined, horizontal aquifers of carbon dioxide (CO2) into saline aquifers is a promising tool for reducing anthropogenic CO2 emissions. At reservoir conditions, the injected CO2 is buoyant relative to the ambient groundwater. The buoyant plume

  4. LOOKING FOR VARIATIONS WITH LATITUDE OF THE BASE OF THE SOLAR CONVECTION ZONE

    E-Print Network [OSTI]

    Monteiro, Mário João

    819 LOOKING FOR VARIATIONS WITH LATITUDE OF THE BASE OF THE SOLAR CONVECTION ZONE M Astronomy Unit, School of Mathematical Sciences, Queen Mary & Westfield College, Mile End Road, London El 4 successfully in determining the basic characteristics of the base of the solar convec- tive region (e

  5. Under consideration for publication in J. Fluid Mech. 1 Stressed horizontal convection

    E-Print Network [OSTI]

    Young, William R.

    in the Gullmarfjord on the west coast of Sweden. When the wind swept over the fjord, the water at the surface flowed to the suggestion of Munk & Wunsch (1998) that mechanical energy sources -- such as the wind stress observed by Sandstr¨om (1908) -- are necessary to sustain the ocean circulation. Recent work on horizontal convection

  6. Antisymmetric Polar Modes of Thermal Convection in Rotating Spherical Fluid Shells at High Taylor Numbers

    E-Print Network [OSTI]

    Marques, Francisco

    to the inner sphere at the equator (polar mode). The exponent of the power law determined from the asymptotic's magnetic field is generated in its interior by convection driven by thermal and compositional buoy- ancy good reviews of the state of the art on this subject. The theoretical paper [7] established

  7. 2 Geomagnetic dipole moment collapse by convective mixing in the core 3 Lijun Liu1

    E-Print Network [OSTI]

    Olson, Peter L.

    through 13 expulsion of mostly poloidal magnetic field by convective 14 upwellings. The dipole fieldkinematic dynamo waves [Gubbins, 1987]. Like resistive 58instabilities, dynamo wave mechanisms are limited on relatively long time scales 61in the outer core. 62[4] Numerical dynamos reveal there are fast, advection- 63

  8. GEVREY REGULARITY FOR THE ATTRACTOR OF A PARTIALLY DISSIPATIVE MODEL OF B'ENARD CONVECTION

    E-Print Network [OSTI]

    Oliver, Marcel

    Abstract.Convective flow though a porous medium can be modeled by Darcy's law_a linear, weakly damped momentum equation_coupled with an advection-diffusion equation for the energy. The solution semigroup for * *this system is not smoothing, and the solution of the momentum equation does

  9. Deep convection in the Irminger Sea forced by the Greenland tip jet

    E-Print Network [OSTI]

    Pickart, Robert S.

    Deep convection in the Irminger Sea forced by the Greenland tip jet Robert S. Pickart*, Michael A atmospheric jet known as the Greenland tip jet, which forms periodically in the lee of Cape Farewell, Greenland, and is associated with elevated heat flux and strong wind stress curl. Using a history of tip

  10. 3D convection simulations of the outer layers of the Sun using realistic physics

    E-Print Network [OSTI]

    F. J. Robinson; P. Demarque; L. H. Li; S. Sofia; Y. -C. Kim; K. L. Chan; D. B. Guenther

    2002-12-12T23:59:59.000Z

    This paper describes a series of 3D simulations of shallow inefficient convection in the outer layers of the Sun. The computational domain is a closed box containing the convection-radiation transition layer, located at the top of the solar convection zone. The most salient features of the simulations are that: i)The position of the lower boundary can have a major effect on the characteristics of solar surface convection (thermal structure, kinetic energy and turbulent pressure). ii)The width of the box has only a minor effect on the thermal structure, but a more significant effect on the dynamics (rms velocities). iii)Between the surface and a depth of 1 Mm, even though the density and pressure increase by an order of magnitude, the vertical correlation length of vertical velocity is always close to 600 km. iv) In this region the vertical velocity cannot be scaled by the pressure or the density scale height. This casts doubt on the applicability of the mixing length theory, not only in the superadiabatic layer, but also in the adjacent underlying layers. v) The final statistically steady state is not strictly dependent on the initial atmospheric stratification.

  11. The effect of shear on heat budgets in a simulated Mesoscale Convective System 

    E-Print Network [OSTI]

    Shaw, Justin David

    2000-01-01T23:59:59.000Z

    in the lowest 2.5 km varying from 10-25 m s?¹. A fourth simulation was conducted using the weak wind shear profile and incorporating ice microphysics. An analysis domain was produced every two hours for the northern and southern portions of the convective line...

  12. Movement of oxygen from the atmosphere to the mitochondria occurs via several convective and diffusive steps

    E-Print Network [OSTI]

    Bennett, Albert F.

    4111 Movement of oxygen from the atmosphere to the mitochondria occurs via several convective and diffusive steps (Weibel et al., 1981). In mammals, maximal rate of oxygen consumption (VOmax) is not limited by any one step of the oxygen cascade; rather limitations to VOmax are distributed across all steps

  13. Small-scale magnetic buoyancy and magnetic pumping effects in a turbulent convection

    E-Print Network [OSTI]

    I. Rogachevskii; N. Kleeorin

    2006-05-18T23:59:59.000Z

    We determine the nonlinear drift velocities of the mean magnetic field and nonlinear turbulent magnetic diffusion in a turbulent convection. We show that the nonlinear drift velocities are caused by the three kinds of the inhomogeneities, i.e., inhomogeneous turbulence; the nonuniform fluid density and the nonuniform turbulent heat flux. The inhomogeneous turbulence results in the well-known turbulent diamagnetic and paramagnetic velocities. The nonlinear drift velocities of the mean magnetic field cause the small-scale magnetic buoyancy and magnetic pumping effects in the turbulent convection. These phenomena are different from the large-scale magnetic buoyancy and magnetic pumping effects which are due to the effect of the mean magnetic field on the large-scale density stratified fluid flow. The small-scale magnetic buoyancy and magnetic pumping can be stronger than these large-scale effects when the mean magnetic field is smaller than the equipartition field. We discuss the small-scale magnetic buoyancy and magnetic pumping effects in the context of the solar and stellar turbulent convection. We demonstrate also that the nonlinear turbulent magnetic diffusion in the turbulent convection is anisotropic even for a weak mean magnetic field. In particular, it is enhanced in the radial direction. The magnetic fluctuations due to the small-scale dynamo increase the turbulent magnetic diffusion of the toroidal component of the mean magnetic field, while they do not affect the turbulent magnetic diffusion of the poloidal field.

  14. Dynamo Action in the Solar Convection Zone and Tachocline: Pumping and Organization of Toroidal Fields

    E-Print Network [OSTI]

    Matthew Browning; Mark S. Miesch; Allan Sacha Brun; Juri Toomre

    2006-09-06T23:59:59.000Z

    We present the first results from three-dimensional spherical shell simulations of magnetic dynamo action realized by turbulent convection penetrating downward into a tachocline of rotational shear. This permits us to assess several dynamical elements believed to be crucial to the operation of the solar global dynamo, variously involving differential rotation resulting from convection, magnetic pumping, and amplification of fields by stretching within the tachocline. The simulations reveal that strong axisymmetric toroidal magnetic fields (about 3000 G in strength) are realized within the lower stable layer, unlike in the convection zone where fluctuating fields are predominant. The toroidal fields in the stable layer possess a striking persistent antisymmetric parity, with fields in the northern hemisphere largely of opposite polarity to those in the southern hemisphere. The associated mean poloidal magnetic fields there have a clear dipolar geometry, but we have not yet observed any distinctive reversals or latitudinal propagation. The presence of these deep magnetic fields appears to stabilize the sense of mean fields produced by vigorous dynamo action in the bulk of the convection zone.

  15. Modeling of passive microwave responses in convective situations using output from mesoscale models

    E-Print Network [OSTI]

    Pardo-Carrión, Juan R.

    Modeling of passive microwave responses in convective situations using output from mesoscale models using output from nonhydrostatic mesoscale atmospheric model, Meso-NH, simulations. The radiative for a systematic evaluation of the mesoscale cloud models. An overall good agreement is obtained for both

  16. Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena: Katabatic winds and boundary layer convection

    E-Print Network [OSTI]

    Spiga, Aymeric

    Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena Keywords: Mesoscale meteorology Katabatic winds Boundary layer convection Comparative planetology a b s t r a c t Terrestrial and Martian atmospheres are both characterised by a large variety of mesoscale

  17. Computational Modeling and Experiments of Natural Convection for a Titan Montgolfiere

    E-Print Network [OSTI]

    Dabiri, John O.

    viscosity cp Specific heat k Conductivity h Heat transfer coefficient Q Total heat input s(x) Distribution-seventh that of Earth, requires a significantly reduced heat input for a given balloon mass, compared to Earth. The smaller heat input also implies that natural convection, rather than radiation, will dominate the heat

  18. Solutions for nonlinear convection in the presence of a lateral boundary

    E-Print Network [OSTI]

    Skeldon, Anne C.

    Solutions for nonlinear convection in the presence of a lateral boundary P.G. Daniels, D. Ho & A into account the effect of a lateral boundary and without the need for extensive numerical calculations crystals, in crystal growth and in the buckling of plates (see, for example, [1]). A key issue

  19. PHYSICS OF FLUIDS 25, 094105 (2013) Onset of convection with fluid compressibility

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    2013-01-01T23:59:59.000Z

    2013; published online 25 September 2013) The density increase from carbon dioxide (CO2) dissolution. The convection is important for both CO2 sequestration in deep saline aquifers and CO2 improved oil recovery from to interface movement may be much more pronounced in hydro- carbons than in water. This could have important

  20. Satellite retrieval of convective cloud base temperature based on the NPP/VIIRS Imager

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    of Shaanxi Province, Xi'an, China, 2 Institute of Earth Sciences, The Hebrew University of Jerusalem potential energy and thus improving the prediction of convection and precipitation, especially in remote weather prediction models can improve the weather forecast and especially the quantitative precipitation

  1. Quality of the Target Area for Metrics with Different Nonlinearities in a Mesoscale Convective System

    E-Print Network [OSTI]

    Meng, Zhiyong

    , on the forecast error of strongly nonlinear rainfall and weakly nonlinear total energy around the initial vortex of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China (Manuscript received 31 area for forecast metrics with different nonlinearities in a mesoscale convective vortex

  2. Convection in Arc Weld Pools Electromagnetic and surface tension forces are shown to

    E-Print Network [OSTI]

    Eagar, Thomas W.

    Convection in Arc Weld Pools Electromagnetic and surface tension forces are shown to dominate flow tension forces. It is shown that the electromag- netic and surface tension forces domi- nate the flow by experimental measurements of segrega- tion in the weld pool. It is also shown that the surface tension driven

  3. Marangoni convection induced by a nonlinear temperature-dependent surface tension

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    23 Marangoni convection induced by a nonlinear temperature-dependent surface tension A. Cloot and G'instabilité de Marangoni dans une mince lame horizontale de fluide lorsque la tension de surface est une fonction ofthe surface- tension with respect to the temperature is studied. This behaviour is typical of some

  4. Time-independent square patterns in surface-tension-driven Benard convection

    E-Print Network [OSTI]

    Texas at Austin. University of

    Time-independent square patterns in surface-tension-driven Be´nard convection Michael F. Schatza The transition between hexagonal and square patterns is investigated in laboratory experiments on surface-tension, the transition from hexagons to other patterns was unexplored for the surface-tension-driven regime of Be

  5. Evaluation of mesoscale convective systems in South America using multiple satellite products and an objectbased approach

    E-Print Network [OSTI]

    Ebert, Beth

    and an objectbased approach E. M. C. Demaria,1 D. A. Rodriguez,2 E. E. Ebert,3 P. Salio,4 F. Su,5 and J. B. Valdes1 to precipitation was mitigating the effect of the errors. Citation: Demaria, E. M. C., D. A. Rodriguez, E. E. Ebert, P. Salio, F. Su, and J. B. Valdes (2011), Evaluation of mesoscale convective systems in South

  6. The Joint Essential Numerical Range of operators

    E-Print Network [OSTI]

    Li, Chi-Kwong

    The Joint Essential Numerical Range of operators: Convexity and Related Results Chi-Kwong Li Classification 47A12, 47A13, 47A55. Keywords Joint essential numerical range, self-adjoint operator, Hilbert the joint behavior of several operators A1, . . . , Am. One may see [1, 5, 12, 14, 15, 16, 19, 23, 28, 31

  7. Range gated imaging experiments using gated intensifiers

    SciTech Connect (OSTI)

    McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M.; Payton, J.; Pena-Abeyta, C.R.

    1999-03-01T23:59:59.000Z

    A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.

  8. Effective range from tetramer dissociation data

    E-Print Network [OSTI]

    Hadizadeh, M R; Tomio, Lauro; Delfino, A; Frederico, T

    2012-01-01T23:59:59.000Z

    The shifts in the four-body recombination peaks, due to lowest order range corrections in the zero range results close to the unitary limit, are obtained and used to extract the corresponding effective range of a given atomic system. From the experimental values of the tetramer dissociation positions of an ultracold gas of cesium atoms close to broad Feshbach resonances, the effective ranges are extracted, with a weighted average given by 3.9$\\pm 0.8 R_{{vdW}}$, where $R_{{vdW}}$ is the van der Waals length scale. This result is consistent with the van der Waals potential tail for the $Cs_2$ system. The method can be generally applied to other cold atom experimental setups to determine the corresponding effective range.

  9. The effects of convection criteria on the evolution of population III stars and the detectability of their supernovae

    E-Print Network [OSTI]

    Lawlor, T M; Teffs, J; MacDonald, J

    2015-01-01T23:59:59.000Z

    The first stars continue to elude modern telescopes, but much has been accomplished in observing the glow of the first galaxies. As detection capabilities improve we will eventually resolve these galaxies, but hopes of observing an individual star remains dim for the foreseeable future. However, our first view of an individual first star may be possible due to its explosion. In this work, we present evolution calculations for Population III (Pop III) stars and their subsequent supernovae explosions. Our evolution models include a mass range of 15 - 100 M$_\\odot$, each with initial heavy element abundance Z = 10-14. Our models are evolved from pre-main sequence through formation of an iron core, and thus near to core collapse. We find that modelling the evolution of these stars is very sensitive to the choice of convection criterion; here we provide evolution results using both the Schwarzschild and Ledoux criteria. We also use the final structure from our models for numerical simulation of their supernovae li...

  10. Neutron scattering and extra short range interactions

    E-Print Network [OSTI]

    V. V. Nesvizhevsky; G. Pignol; K. V. Protasov

    2007-11-14T23:59:59.000Z

    The available data on neutron scattering were analyzed to constrain a hypothetical new short-range interaction. We show that these constraints are several orders of magnitude better than those usually cited in the range between 1 pm and 5 nm. This distance range occupies an intermediate space between collider searches for strongly coupled heavy bosons and searches for new weak macroscopic forces. We emphasise the reliability of the neutron constraints in so far as they provide several independent strategies. We have identified the most promising way to improve them.

  11. A blue sky catastrophe in double-diffusive convection

    E-Print Network [OSTI]

    Esteban Meca; Isabel Mercader; Oriol Batiste; Laureano Ramirez-Piscina

    2004-05-27T23:59:59.000Z

    A global bifurcation of the blue sky catastrophe type has been found in a small Prandtl number binary mixture contained in a laterally heated cavity. The system has been studied numerically applying the tools of bifurcation theory. The catastrophe corresponds to the destruction of an orbit which, for a large range of Rayleigh numbers, is the only stable solution. This orbit is born in a global saddle-loop bifurcation and becomes chaotic in a period doubling cascade just before its disappearance at the blue sky catastrophe.

  12. Long range transport of acid rain precursors

    E-Print Network [OSTI]

    Fay, James A.

    1983-01-01T23:59:59.000Z

    A model of the long range transport of primary and secondary pollutants derived by Fay and Rosenzweig (1) is applied to the problem of the transport of acid rain precursors. The model describes the long term average (annual ...

  13. APS Long Range Schedule FY1996

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Long Range Commissioning Schedule for FY1996 Date First Shift 0:00-8:00 Second Shift 8:00-16:00 Third Shift 16:00-24:00 31596 SR Studies 1-ID-A Shielding Verification SR Studies...

  14. Descriptions of Range and Pasture Plants

    E-Print Network [OSTI]

    Ragsdale, Bobby; Welch, Tommy G.

    2000-05-03T23:59:59.000Z

    Characteristics of common range and pasture plants are listed in this publication. The common and scientific name of each species are given, along with the species' value as a grazing plant for wildlife and livestock....

  15. Active dendrites enhance neuronal dynamic range

    E-Print Network [OSTI]

    Leonardo L. Gollo; Osame Kinouchi; Mauro Copelli

    2009-08-08T23:59:59.000Z

    Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the last decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of active dendritic trees is a highly non-linear function of their afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease of dynamic range.

  16. Systematic ranging and late warning asteroid impacts

    E-Print Network [OSTI]

    Farnocchia, D; Micheli, M

    2015-01-01T23:59:59.000Z

    We describe systematic ranging, an orbit determination technique especially suitable to assess the near-term Earth impact hazard posed by newly discovered asteroids. For these late warning cases, the time interval covered by the observations is generally short, perhaps a few hours or even less, which leads to severe degeneracies in the orbit estimation process. The systematic ranging approach gets around these degeneracies by performing a raster scan in the poorly-constrained space of topocentric range and range rate, while the plane of sky position and motion are directly tied to the recorded observations. This scan allows us to identify regions corresponding to collision solutions, as well as potential impact times and locations. From the probability distribution of the observation errors, we obtain a probability distribution in the orbital space and then estimate the probability of an Earth impact. We show how this technique is effective for a number of examples, including 2008 TC3 and 2014 AA, the only tw...

  17. COLORADO FRONT RANGE SEISMICITY AND SEISMIC HAZARD

    E-Print Network [OSTI]

    Sheehan, Anne F.

    COLORADO FRONT RANGE SEISMICITY AND SEISMIC HAZARD Anne F. Sheehan University of Colorado, seismic, seismicity, crust, fault, hazard ABSTRACT Construction of seismic hazard and risk maps depends upon carefully constrained input parameters including background seismicity, seismic attenuation

  18. Long range interactions in nanoscale science

    E-Print Network [OSTI]

    Rajter, Richard F.

    Our understanding of the “long range” electrodynamic, electrostatic, and polar interactions that dominate the organization of small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces ...

  19. Programmable near-infrared ranging system

    DOE Patents [OSTI]

    Everett, Jr., Hobart R. (San Diego, CA)

    1989-01-01T23:59:59.000Z

    A high angular resolution ranging system particularly suitable for indoor plications involving mobile robot navigation and collision avoidance uses a programmable array of light emitters that can be sequentially incremented by a microprocessor. A plurality of adjustable level threshold detectors are used in an optical receiver for detecting the threshold level of the light echoes produced when light emitted from one or more of the emitters is reflected by a target or object in the scan path of the ranging system.

  20. Range Con: a management evaluation system for assessing sucess of selected range improvement practices

    E-Print Network [OSTI]

    Ekblad, Steven Linn

    1989-01-01T23:59:59.000Z

    strategic resource management plans. Individual management skills and managerial environment have not been considered when predicting biological and economic response of range management practices. Risk for individual managers adopting unsuited... APPENDIX Prototype Range Management Skills Survey. Range Management Skills Survey Survey Data Tables. Validation Figures. VITA 64 65 74 92 104 106 1X LIST OP FIGURES FIGURE Page 1. The Range Con expert system in relation to the Resource...

  1. Laser Range Finder Objective: Use a forward pointing laser range finder to

    E-Print Network [OSTI]

    Wirthlin, Michael J.

    Laser Range Finder Objective: Use a forward pointing laser range finder to detect and avoid obstacles. Principle Investigators: Randy Beard, Tim McLain Laser Range Finder Opti-Logic RS400 Laser path, laser detects object. 2. Upon detection, insert cylindrical object into world map and plan path

  2. Low-level convergence and its role in convective intensity and frequency over the Houston lightning and rainfall anomaly

    E-Print Network [OSTI]

    McNear, Veronica Ann

    2007-09-17T23:59:59.000Z

    . By using these images along with average lightning, rainfall, and reflectivity for a large Houston-centered domain, it was possible to discern a correlation between low-level convergence and convection. Also, past findings of enhancement in lightning...

  3. Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Parameterization

    E-Print Network [OSTI]

    Zhang, Guang Jun

    Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Two 9-yr runs of the NCAR Community Climate Model version 3 (CCM3) are compared in their simulations

  4. Tropical precipitation variability and convectively coupled equatorial waves1 on submonthly time-scales in reanalyses and TRMM2

    E-Print Network [OSTI]

    Alexander, M. Joan

    convection plays a vital role in global climate by driving large-scale circulation,41 releasing latent heat, modulating radiative forcing, and most importantly redistributing water in42 the earth system. Due to complex

  5. Cloud-to-ground lightning characteristics of warm season Mesoscale Convection Systems in the Central United States: 1992-1993

    E-Print Network [OSTI]

    Hoeth, Brian Richard

    1998-01-01T23:59:59.000Z

    This study provides a detailed analysis of cloud-to-aphics. ground (CG) lightning flashes within individual Mesoscale Convective Systems (MCSs) that occurred in the Central United States during May-August of 1992 and 1993. Analysis of the CG...

  6. Non-PEGylated liposomes for convection-enhanced delivery of topotecan and gadodiamide in malignant glioma: initial experience

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    Novel nano- liposomal CPT-11 infused by convection-enhancedregimen of topoCED co-infused with gadoCED greatly increasedconcentrations (1.6 mg/ ml) co-infused with gadoCED showed

  7. The evolution of total lightning and radar reflectivity characteristics of two mesoscale convective systems over Houston, Texas

    E-Print Network [OSTI]

    Hodapp, Charles Lee

    2009-05-15T23:59:59.000Z

    originated in the convective or transition regions. Both in-situ charging mechanisms created by the development of the mesoscale updraft and charge advection by the front-to-rear flow likely contribute to the increased electrification and lightning...

  8. Segregation of Particulate Solids: Segregation via Convection S. Luding(*/**), J. Duran(*), E. Cl'ement(*), J. Rajchenbach(*)

    E-Print Network [OSTI]

    Luding, Stefan

    they examine granular convection with nuclear magnetic resonance imaging methods. Eventually, detailed are discussed: Segregation in a powder bed, at the surface of a powder bed and in a fluidized powder bed

  9. Precipitation Hydrometeor Type Relative to the Mesoscale Airflow in Oceanic Deep Convection of the Madden-Julian Oscillation

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    1 Precipitation Hydrometeor Type Relative to the Mesoscale Airflow in Oceanic Deep located relative to mesoscale air motions Heavy rain and riming occur downstream of mesoscale Abstract Composite analysis of near-equatorial oceanic mesoscale convective systems (MCSs

  10. Final Report on Evaluating the Representation and Impact of Convective Processes in the NCAR Community Climate System Model

    SciTech Connect (OSTI)

    X. Wu, G. J. Zhang

    2008-04-23T23:59:59.000Z

    Convection and clouds affect atmospheric temperature, moisture and wind fields through the heat of condensation and evaporation and through redistributions of heat, moisture and momentum. Individual clouds have a spatial scale of less than 10 km, much smaller than the grid size of several hundred kilometers used in climate models. Therefore the effects of clouds must be approximated in terms of variables that the model can resolve. Deriving such formulations for convection and clouds has been a major challenge for the climate modeling community due to the lack of observations of cloud and microphysical properties. The objective of our DOE CCPP project is to evaluate and improve the representation of convection schemes developed by PIs in the NCAR (National Center for Atmospheric Research) Community Climate System Model (CCSM) and study its impact on global climate simulations. • The project resulted in nine peer-reviewed publications and numerous scientific presentations that directly address the CCPP’s scientific objective of improving climate models. • We developed a package of improved convection parameterization that includes improved closure, trigger condition for convection, and comprehensive treatment of convective momentum transport. • We implemented the new convection parameterization package into several versions of the NCAR models (both coupled and uncoupled). This has led to 1) Improved simulation of seasonal migration of ITCZ; 2) Improved shortwave cloud radiative forcing response to El Niño in CAM3; 3) Improved MJO simulation in both uncoupled and coupled model; and 4) Improved simulation of ENSO in coupled model. • Using the dynamic core of CCM3, we isolated the dynamic effects of convective momentum transport. • We implemented mosaic treatment of subgrid-scale cloud-radiation interaction in CCM3.

  11. Properties of inflow and downdraft air of tropical mesoscale convective systems and the effect of downdrafts on the surface fluxes

    E-Print Network [OSTI]

    Griffith, Jeane Margaret

    1992-01-01T23:59:59.000Z

    PROPERTIES OF INFLOW AND DOWNDRAFT AIR OF TROPICAL MESOSCALE CONVECTIVE SYSTEMS AND THE EFFECT OF DOWNDRAFTS ON THE SURFACE FLUXES A Thesis by JEANE MARGARET GRIFFITH Submitted to the Office of Graduate Studies of Texas A&M University... in partial fulfillment of the requirements for the degree of MAS'IER OF SCIENCE December 1992 Major Subject: Meteorology PROPERTIES OF THE INFLOW AND DOWNDRAFT AIR OF TROPICAL MESOSCALE CONVECTIVE SYSTEMS AND THE EFFECT OF DOWNDRAFTS ON THE SURFACE...

  12. Topological phases with long-range interactions

    E-Print Network [OSTI]

    Gong, Zhe-Xuan; Hu, Anzi; Wall, Michael L; Foss-Feig, Michael; Gorshkov, Alexey V

    2015-01-01T23:59:59.000Z

    Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.

  13. Supersymmetric inversion of effective-range expansions

    E-Print Network [OSTI]

    Bikashkali Midya; Jérémie Evrard; Sylvain Abramowicz; O. L. Ramírez Suárez; Jean-Marc Sparenberg

    2015-05-26T23:59:59.000Z

    A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.

  14. Supersymmetric inversion of effective-range expansions

    E-Print Network [OSTI]

    Midya, Bikashkali; Abramowicz, Sylvain; Suárez, O L Ramírez; Sparenberg, Jean-Marc

    2015-01-01T23:59:59.000Z

    A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.

  15. Supersymmetric inversion of effective-range expansions

    E-Print Network [OSTI]

    Bikashkali Midya; Jérémie Evrard; Sylvain Abramowicz; O. L. Ramírez Suárez; Jean-Marc Sparenberg

    2015-01-16T23:59:59.000Z

    A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.

  16. Topological phases with long-range interactions

    E-Print Network [OSTI]

    Zhe-Xuan Gong; Mohammad F. Maghrebi; Anzi Hu; Michael L. Wall; Michael Foss-Feig; Alexey V. Gorshkov

    2015-05-12T23:59:59.000Z

    Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.

  17. Two-dimensional segmentation of small convective patterns in radiation hydrodynamics simulations

    E-Print Network [OSTI]

    Lemmerer, B; Hanslmeier, A; Veronig, A; Thonhofer, S; Grimm-Strele, H; Kariyappa, R

    2015-01-01T23:59:59.000Z

    Recent results from high-resolution solar granulation observations indicate the existence of a population of small granular cells that are smaller than 600 km in diameter. These small convective cells strongly contribute to the total area of granules and are located in the intergranular lanes, where they form clusters and chains. We study high-resolution radiation hydrodynamics simulations of the upper convection zone and photosphere to detect small granular cells, define their spatial alignment, and analyze their physical properties. We developed an automated image-segmentation algorithm specifically adapted to high-resolution simulations to identify granules. The resulting segmentation masks were applied to physical quantities, such as intensity and vertical velocity profiles, provided by the simulation. A new clustering algorithm was developed to study the alignment of small granular cells. This study shows that small granules make a distinct contribution to the total area of granules and form clusters of ...

  18. Noise-Sustained Convective Instability in a Magnetized Taylor-Couette Flow

    SciTech Connect (OSTI)

    W. Liu

    2009-02-20T23:59:59.000Z

    The helical magnetorotational instability of the magnetized Taylor-Couette flow is studied numerically in a finite cylinder. A distant upstream insulating boundary is shown to stabilize the convective instability entirely while reducing the growth rate of the absolute instability. The reduction is less severe with larger height. After modeling the boundary conditions properly, the wave patterns observed in the experiment turn out to be a noise-sustained convective instability. After the source of the noise resulted from unstable Ekman and Stewartson layers is switched off, a slowly-decaying inertial oscillation is observed in the simulation. We reach the conclusion that the experiments completed to date have not yet reached the regime of absolute instability.

  19. Angular momentum fluctuations in the convective helium shell of massive stars

    E-Print Network [OSTI]

    Gilkis, Avishai

    2015-01-01T23:59:59.000Z

    We find significant fluctuations of angular momentum within the convective helium shell of a pre-collapse massive star - a core-collapse supernova progenitor - which may facilitate the formation of accretion disks and jets that can explode the star. The convective flow in our model of an evolved M_ZAMS=15Msun star, computed with the sub-sonic hydrodynamic solver MAESTRO, contains entire shells with net angular momentum in different directions. Such a distribution of angular momentum may give rise to several episodes of accretion disks with varying axes around the newly formed neutron star or black hole. The accretion disks in turn might launch jets that can explode the star in the frame of the jittering-jets model.

  20. The Mid-Latitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Petersen,W.; Jensen,M.; Genio, A. D.; Giangrande, S.; Heymsfield, A.; Heymsfield, G.; Hou, A.; Kollias, P.; Orr, B.; Rutledge, S.; Schwaller, M.; Zipser, E.

    2010-03-15T23:59:59.000Z

    The Midlatitude Continental Convective Cloud Experiment (MC3E) will take place in central Oklahoma during the April-May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy Atmospheric Radition Measurement Program and the National Aeronautics and Space Administration's (NASA) Global Precipitation Measurement (GPM) mission Ground Validation program. The Intensive Observation Period leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall observations over land that have never before been available. Several different components of convective processes tangible to the convective parameterization problem are targeted such as, pre-convective environment and convective initiation, updraft / downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, influence on the environment and radiation and a detailed description of the large-scale forcing. MC3E will use a new multi-scale observing strategy with the participation of a network of distributed sensors (both passive and active). The approach is to document in 3-D not only the full spectrum of precipitation rates, but also clouds, winds and moisture in an attempt to provide a holistic view of convective clouds and their feedback with the environment. A goal is to measure cloud and precipitation transitions and environmental quantities that are important for satellite retrieval algorithms, convective parameterization in large-scale models and cloud-resolving model simulations. This will be accomplished through the deployment of several different elements that complement the existing (and soon to become available) ARM facilities: a network of radiosonde stations, NASA scanning multi-frequency/parameter radar systems at three different frequencies (Ka/Ku/S), high-altitude remote sensing and in situ aircraft, wind profilers and a network of surface disdrometers. In addition to these special MC3E instruments, there will be important new instrumentation deployed by DOE at the ARM site including: 3 networked scanning X-band radar systems, a C-band scanning radar, a dual wavelength (Ka/W) scanning cloud radar, a Doppler lidar and upgraded vertically pointing millimeter cloud radar (MMCR) and micropulse lidar (MPL).To fully describe the properties of precipitating cloud systems, both in situ and remote sensing airborne observations are necessary. The NASA GPM-funded University of North Dakota (UND) Citation will provide in situ observations of precipitation-sized particles, ice freezing nuclei and aerosol concentrations. As a complement to the UND Citation's in situ observations, the NASA ER-2 will provide a high altitude satellite simulator platform that carrying a Ka/Ku band radar and passive microwave radiometers (10-183 GHZ).

  1. Convective Signals from Surface Measurements at ARM Tropical Western Pacific Site: Manus

    SciTech Connect (OSTI)

    Wang, Yi; Long, Charles N.; Mather, James H.; Liu, Xiaodong

    2011-02-23T23:59:59.000Z

    The Madden-Julian Oscillation (MJO) signal has been detected using observations from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Tropical Western Pacific (TWP). With downwelling shortwave radiative fluxes and fractional sky cover from the ACRF TWP Manus site, and the statistical tools of wavelet and spectrum power, we report finding major convective signals from surface observations spanning the period from 1996 to 2006. Our findings are confirmed with the satellite-retrieved values of precipitation from the Global Precipitation Climatology Project (GPCP), and interpolated outgoing longwave radiation (OLR) satellite measurements from the National Oceanic and Atmospheric Administration (NOAA) for the same location. Our results indicate that the MJO convective signal has a strong seasonal-to-interannual evolution that is likely correlated with the interannual variability of El Ni ˜no Southern Oscillation (ENSO).

  2. Noise-sustained convective instability in a magnetized Taylor-Couette flow

    SciTech Connect (OSTI)

    Liu, Wei [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    The helical magnetorotational instability of the magnetized Taylor-Couette flow is studied numerically in a finite cylinder. A distant upstream insulating boundary is shown to stabilize the convective instability entirely while reducing the growth rate of the absolute instability. The reduction is less severe with larger height. After modeling the boundary conditions properly, the wave patterns observed in the experiment turn out to be a noise-sustained convective instability. After the source of the noise resulted from unstable Ekman and Stewartson layers is switched off, a slowly-decaying inertial oscillation is observed in the simulation. We reach the conclusion that the experiments completed to date have not yet reached the regime of absolute instability.

  3. Millennial-scale stable oscillations between sea ice and convective deep water formation

    E-Print Network [OSTI]

    Saha, Raj

    2015-01-01T23:59:59.000Z

    During the last ice age there were several quasi-periodic abrupt warming events. The climatic effects of the so-called Dansgaard-Oeschger (DO) events were felt globally, although the North Atlantic experienced the largest and most abrupt temperature anomalies. Similar but weaker oscillations also took place during the interglacial period. This paper proposes an auto-oscillatory mechanism between sea ice and convective deep water formation in the north Atlantic as the source of the persistent cycles. A simple dynamical model is constructed by coupling and slightly modifying two existing models of ocean circulation and sea ice. The model exhibits mixed mode oscillations, consisting of decadal scale small amplitude oscillations, and a large amplitude relaxation fluctuation. The decadal oscillations occur due to the insulating effect of sea ice and leads to periodic ventilation of heat from the polar ocean. Gradually an instability builds up in the polar column and results in an abrupt initiation of convection an...

  4. Heat transfers in a double-skin roof ventilated by natural convection in summer time

    E-Print Network [OSTI]

    Biwole, Pascal; Pompeo, C

    2013-01-01T23:59:59.000Z

    The double-skin roofs investigated in this paper are formed by adding a metallic screen on an existing sheet metal roof. The system enhances passive cooling of dwellings and can help diminishing power costs for air conditioning in summer or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers are investigated. Depending on its surface properties, the screen reflects a large amount of oncoming solar radiation. Natural convection in the channel underneath drives off the residual heat. The bi-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters for the system's efficiency. They are, by order of importance, the sheet metal surface emissivity, the screen internal and external surface emissivity, the insulation thickness and the inclination angle for a channel width over 6 cm. The influence of those parameters on Rayleigh and Nusselt numbers is also investigated. Temperature and air velocity profiles on seve...

  5. Influence of a coronal envelope as a free boundary to global convective dynamo simulations

    E-Print Network [OSTI]

    Warnecke, Jörn; Käpylä, Maarit J; Brandenburg, Axel

    2015-01-01T23:59:59.000Z

    We explore the effects of an outer stably stratified coronal envelope on rotating turbulent convection, differential rotation, and large-scale dynamo action in spherical wedge models of the Sun. We solve the compressible magnetohydrodynamic equations in a two-layer model with unstable stratification below the surface, representing the convection zone, and a stably stratified outer layer, the coronal envelope. The interface emulates essentially a free surface. We compare with models that have no coronal envelope. The presence of a coronal envelope is found to modify the Reynolds stress and the $\\Lambda$-effect resulting in a weaker and non-cylindrical differential rotation. This is related to the reduced latitudinal temperature variations, which are caused by and dependent on the Coriolis force. Some simulations develop a rudimentary near-surface shear layer, which we can relate to a sign change of the meridional Reynolds stress term in the thermal wind balance equation. Furthermore, the presence of a free sur...

  6. A Compressible High-Order Unstructured Spectral Difference Code for Stratified Convection in Rotating Spherical Shells

    E-Print Network [OSTI]

    Wang, Junfeng; Miesch, Mark S

    2015-01-01T23:59:59.000Z

    We present a novel and powerful Compressible High-ORder Unstructured Spectral-difference (CHORUS) code for simulating thermal convection and related fluid dynamics in the interiors of stars and planets. The computational geometries are treated as rotating spherical shells filled with stratified gas. The hydrodynamic equations are discretized by a robust and efficient high-order Spectral Difference Method (SDM) on unstructured meshes. The computational stencil of the spectral difference method is compact and advantageous for parallel processing. CHORUS demonstrates excellent parallel performance for all test cases reported in this paper, scaling up to 12,000 cores on the Yellowstone High-Performance Computing cluster at NCAR. The code is verified by defining two benchmark cases for global convection in Jupiter and the Sun. CHORUS results are compared with results from the ASH code and good agreement is found. The CHORUS code creates new opportunities for simulating such varied phenomena as multi-scale solar co...

  7. The First Second of a Type-II Supernova: Convection, Accretion, and Shock Propagation

    E-Print Network [OSTI]

    H. -Thomas Janka; Ewald Mueller

    1995-03-03T23:59:59.000Z

    One- and two-dimensional hydrodynamical simulations of neutrino-driven supernova explosions are discussed. The simulations cover the phase between the stagnation of the prompt shock and about one second after core bounce. Systematic variation of the neutrino fluxes from the neutrino sphere shows that the explosion energy, explosion time scale, initial mass of the protoneutron star, and explosive nucleosynthesis of iron-group elements depend sensitively on the strength of the neutrino heating during the first few 100 ms after shock formation. Convective overturn in the neutrino-heated region behind the shock is a crucial help for the explosion only in a narrow window of neutrino luminosities. Here powerful explosions can be obtained only in the multi-dimensional case. For higher core-neutrino fluxes also spherically symmetrical models yield energetic explosions, while for lower luminosities even with convection no strong explosions occur.

  8. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    SciTech Connect (OSTI)

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    2012-10-25T23:59:59.000Z

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  9. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  10. Non-Darcian forced convection in porous media with anisotropic dispersion

    SciTech Connect (OSTI)

    Adnani, P.; Catton, I.; Abdou, M.A. [Univ. of California, Los Angeles, CA (United States)

    1995-05-01T23:59:59.000Z

    Convective heat transfer in a particle packed tube is modeled in this paper. Axial and radial dispersion are both included in the governing equations. Results are compared with experimental data, and with previously developed models that did not include axial dispersion. It is shown that heat transfer in the thermally developing region is affected by axial dispersion when Peclet number is smaller than 10. Graphic results are provided to show the importance of axial dispersion for various Peclet numbers. 17 refs., 5 figs.

  11. Pre-convective environmental conditions indicative of non-tornadic severe thunderstorm winds over Southeast Florida 

    E-Print Network [OSTI]

    Wilhelm, Jeffrey Michael

    1987-01-01T23:59:59.000Z

    thunderstorm wind events over Southeast Florida during the period of study. Upper-air data were obtained for several stations on and around the Florida peninsula. These stations include: Key West, Florida (EYW), West Palm Beach, Florida (PBI), Tampa Bay...PRE-CONVECTIVE ENVIRONMENTAL CONDITIONS INDICATIVE OF NON-TORNADIC SEVERE THUNDERSTORM WINDS OVER SOUTHEAST FLORIDA A Thesis by JEFFREY MICHAEL WILHELM Submitted to the Graduate College of Texas ARM University in partial fulfillment...

  12. Solar dynamo models with alpha-effect and turbulent pumping from local 3D convection calculations

    E-Print Network [OSTI]

    P. J. Käpylä; M. J. Korpi; I. Tuominen

    2006-06-05T23:59:59.000Z

    (abridged) Results from kinematic solar dynamo models employing alpha-effect and turbulent pumping from local convection calculations are presented. We estimate the magnitude of these effects to be around 2-3 m/s. The rotation profile of the Sun as obtained from helioseismology is applied. We obtain an estimate of the ratio of the two induction effects, C_alpha/C_Omega \\approx 10^-3, which we keep fixed in all models. We also include a one-cell meridional circulation pattern having a magnitude of 10-20 m/s near the surface and 1-2 m/s at the bottom of the convection zone. The model essentially represents a distributed turbulent dynamo, as the alpha-effect is nonzero throughout the convection zone, although it concentrates near the bottom of the convection zone obtaining a maximum around 30 degrees of latitude. Turbulent pumping of the mean fields is predominantly down- and equatorward. We find that, when all these effects are included in the model, it is possible to correctly reproduce many features of the solar activity cycle, namely the correct equatorward migration at low latitudes and the polar branch at high latitudes, and the observed negative sign of B_r B_phi. Although the activity clearly shifts towards the equator in comparison to previous models due to the combined action of the alpha-effect peaking at midlatitudes, meridional circulation and latitudinal pumping, most of the activity still occurs at too high latitudes (between 5-60 degrees). Other problems include the relatively narrow parameter space within which the preferred solution is dipolar (A0), and the somewhat too short cycle lengths of the solar-type solutions. The role of the surface shear layer is found to be important only in the case where the alpha-effect has an appreciable magnitude near the surface.

  13. Electrodeposition of high Mo content Ni-Mo alloys under forced convection

    SciTech Connect (OSTI)

    Podlaha, E.J.; Matlosz, M.; Landolt, D. (Ecole Polytechnique Federale de Lausanne, Lausanee (Switzerland). Dept. des materiaux)

    1993-10-01T23:59:59.000Z

    Bright, compact, adherent, metallic Ni-Mo alloys, containing over 48 wt % Mo have been electrodeposited from an aqueous solution. The Mo content, which is the highest achieved so far in induced codeposition of Ni-Mo, was determined by X-ray fluorescence spectroscopy. The absence of oxygen was verified by Auger electron spectroscopy. Electrodeposition experiments were performed on rotating cylinder electrodes and demonstrate that the Mo content of the alloy is strongly influenced by convective transport.

  14. Supercomputers Take a Cue From Microwave Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    many different licenses for different applications," says Shalf. "Just as the consumer electronics chip designers choose a set of processor characteristics appropriate to the...

  15. Solar Pizza Oven Box k - 6

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently AskedEnergyIssues DOE's Nuclear EnergySmart Metersof Energy LEDMarketReady to

  16. Supercomputers Take a Cue From Microwave Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. .Energy8 CareerSupercomputerSupercomputers

  17. Making a Solar Oven | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetterEconomyDr.Energy Maine

  18. Microphysical Effects Determine Macrophysical Response for Aerosol Impacts on Deep Convective Clouds

    SciTech Connect (OSTI)

    Fan, Jiwen; Leung, Lai-Yung R.; Rosenfeld, Daniel; Chen, Qian; Li, Zhanqing; Zhang, Jinqiang; Yan, Hongru

    2013-11-26T23:59:59.000Z

    Deep convective clouds (DCCs) play a crucial role in the general circulation and energy and hydrological cycle of our climate system. Anthropogenic and natural aerosol particles can influence DCCs through changes in cloud properties, precipitation regimes, and radiation balance. Modeling studies have reported both invigoration and suppression of DCCs by aerosols, but none has fully quantified aerosol impacts on convection life cycle and radiative forcing. By conducting multiple month-long cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macro- and micro-physical properties of summer convective clouds in the tropics and mid-latitudes, this study provides the first comprehensive look at how aerosols affect cloud cover, cloud top height (CTH), and radiative forcing. Observations validate these simulation results. We find that microphysical aerosol effects contribute predominantly to increased cloud cover and CTH by inducing larger amount of smaller but longer lasting ice particles in the stratiform/anvils of DCCs with dynamical aerosol effects contributing at most ~ 1/4 of the total increase of cloud cover. The overall effect is a radiative warming in the atmosphere (3 to 5 W m-2) with strong surface cooling (-5 to -8 W m-2). Herein we clearly identified mechanisms more important than and additional to the invigoration effects hypothesized previously that explain the consistent signatures of increased cloud tops area and height by aerosols in DCCs revealed by observations.

  19. Chaotic mean wind in turbulent thermal convection and long-term correlations in solar activity

    E-Print Network [OSTI]

    A. Bershadskii

    2009-12-25T23:59:59.000Z

    It is shown that correlation function of the mean wind velocity in a turbulent thermal convection (Rayleigh number $Ra \\sim 10^{11}$) exhibits exponential decay with a very long correlation time, while corresponding largest Lyapunov exponent is certainly positive. These results together with the reconstructed phase portrait indicate presence of a chaotic component in the examined mean wind. Telegraph approximation is also used to study relative contribution of the chaotic and stochastic components to the mean wind fluctuations and an equilibrium between these components has been studied. Since solar activity is based on the thermal convection processes, it is reasoned that the observed solar activity long-term correlations can be an imprint of the mean wind chaotic properties. In particular, correlation function of the daily sunspots number exhibits exponential decay with a very long correlation time and corresponding largest Lyapunov exponent is certainly positive, also relative contribution of the chaotic and stochastic components follows the same pattern as for the convection mean wind.

  20. Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

    SciTech Connect (OSTI)

    Triplett, C.E.

    1996-12-01T23:59:59.000Z

    This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.

  1. Frictional heating and convective cooling of polycrystalline diamond drag tools during rock cutting

    SciTech Connect (OSTI)

    Ortega, A.; Glowka, D.A.

    1982-01-01T23:59:59.000Z

    A numerical-analytical model is developed to predict temperatures in stud-mounted polycrystalline diamond compact (PDC) drag tools during rock cutting. Experimental measurements of the convective heat transfer coefficient for PDC cutters are used in the model to predict temperatures under typical drilling conditions with fluid flow. The analysis compares favorably with measurements of frictional temperatures in controlled cutting tests on Tennessee marble. It is shown that mean cutter wearflat temperatures can be maintained below the critical value of 750{sup 0}C only under conditions of low friction at the cutter/rock interface. This is true, regardless of the level of convective cooling. In fact, a cooling limit is established above which increases in convective cooling do not further reduce cutter temperatures. The ability of liquid drilling fluids to reduce interface friction is thus shown to be far more important in preventing excessive temperatures than their ability to provide cutter cooling. Due to the relatively high interface friction developed under typical air drilling conditions, it is doubtful that temperatures can be kept subcritical at high rotary speeds in some formations when air is employed as the drilling fluid, regardless of the level of cooling achieved.

  2. A convective-radiative heat transfer model for gas core reactors

    SciTech Connect (OSTI)

    Chen, G.; Anghaie, S. [Univ. of Florida, Gainesville, FL (United States)

    1995-12-31T23:59:59.000Z

    A convective-radiative heat transfer model is developed and used to predict the temperature distribution in gaseous fuel nuclear reactor cores. The axisymmetric, thin layer Navier-Stokes equations with diffusive radiation source term are the basis for this modeling approach. An algebraic turbulence model is used to calculate the eddy viscosity. The Rosseland diffusion approximation is used to model the radiative heat transfer. A hybrid implicit-explicit numerical scheme with Gauss-Seidel iterative process and a highly stretched grid system near wall is employed to solve the governing equations. Several cases with different internal heat generation rates are modeled and analyzed. Results of the temperature distribution, wall heat flux and the associated Nusselt number are presented. The influence of the internal heat generation rate and the wall temperature on the radiative and convective wall heat fluxes are discussed. At gas and wall temperatures close to 3,500 K and 1,600 K, respectively, the radiative and convective heat transfer rates have similar values.

  3. Large-scale weakly nonlinear perturbations of convective magnetic dynamos in a rotating layer

    E-Print Network [OSTI]

    Roman Chertovskih; Vladislav Zheligovsky

    2015-04-26T23:59:59.000Z

    We present a new mechanism for generation of large-scale magnetic field by thermal convection which does not involve the alpha-effect. We consider weakly nonlinear perturbations of space-periodic steady convective magnetic dynamos in a rotating layer that were identified in our previous work. The perturbations have a spatial scale in the horizontal direction that is much larger than the period of the perturbed convective magnetohydrodynamic state. Following the formalism of the multiscale stability theory, we have derived the system of amplitude equations governing the evolution of the leading terms in expansion of the perturbations in power series in the scale ratio. This asymptotic analysis is more involved than in the cases considered earlier, because the kernel of the operator of linearisation has zero-mean neutral modes whose origin lies in the spatial invariance of the perturbed regime, the operator reduced on the generalised kernel has two Jordan normal form blocks of size two, and simplifying symmetries of the perturbed state are now missing. Numerical results for the amplitude equations show that a perturbation, periodic in slow horizontal variable, either decays in time, or blows up at a finite time with amplitudes turning into a periodically-replicated delta-function moving at a constant speed.

  4. Range Creek Calibrated Dates Beta-202190

    E-Print Network [OSTI]

    Provancher, William

    Range Creek Calibrated Dates 0 200 400 600 800 1000 1200 1400 Beta-202190 Beta-175753 Beta-175755 Beta-235067 Beta-202189 Beta-214831 Beta-202188 Beta-202191 Beta-203630 Beta-214832 Beta-175754 Beta a Carbon-14 calibrated date (95% CI) between 1000 and 1200 C.E. (Figure 5: Beta-235067). The calibrated

  5. Compact range for variable-zone measurements

    DOE Patents [OSTI]

    Burnside, Walter D. (Columbus, OH); Rudduck, Roger C. (Columbus, OH); Yu, Jiunn S. (Albuquerque, NM)

    1988-01-01T23:59:59.000Z

    A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

  6. 6, 1018310216, 2006 Long-range transport

    E-Print Network [OSTI]

    Boyer, Edmond

    ACPD 6, 10183­10216, 2006 Long-range transport of Asian dust and air pollutants to Taiwan C.-Y. Lin and air pollutants to Taiwan: observed evidence and model simulation C.-Y. Lin 1 , Z. Wang 2 , W.-N. Chen and air pollutants to Taiwan C.-Y. Lin et al. Title Page Abstract Introduction Conclusions References

  7. Wide temperature range seal for demountable joints

    DOE Patents [OSTI]

    Sixsmith, H.; Valenzuela, J.A.; Nutt, W.E.

    1991-07-23T23:59:59.000Z

    The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof. 6 figures.

  8. Wide temperature range seal for demountable joints

    DOE Patents [OSTI]

    Sixsmith, Herbert (Norwich, VT); Valenzuela, Javier A. (Grantham, NH); Nutt, William E. (Enfield, NH)

    1991-07-23T23:59:59.000Z

    The present invention is directed to a seal for demountable joints operating over a wide temperature range down to liquid helium temperatures. The seal has anti-extrusion guards which prevent extrusion of the soft ductile sealant material, which may be indium or an alloy thereof.

  9. Impulse radar with swept range gate

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1998-09-08T23:59:59.000Z

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna (10), so a background subtraction is not needed, simplifying the circuitry while improving performance. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive (24) and transmit cavities (22) by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. The antennas can be arranged in a side-by-side parallel spaced apart configuration or in a coplanar opposed configuration which significantly reduces main bang coupling.

  10. Impulse radar with swept range gate

    DOE Patents [OSTI]

    McEwan, T.E.

    1998-09-08T23:59:59.000Z

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. The antennas can be arranged in a side-by-side parallel spaced apart configuration or in a coplanar opposed configuration which significantly reduces main bang coupling. 25 figs.

  11. Electrical Engineering Technology (EET) LONG RANGE SCHEDULE

    E-Print Network [OSTI]

    and Machinery C T C T EET 365W Electrical Power & Machinery Laboratory C C, V V C C, V V EET 370T EnergyElectrical Engineering Technology (EET) LONG RANGE SCHEDULE Course Number and Name Fall 2010 Spr 2011 Sum 2011 Fall 2011 Spr 2012 Sum 2012 Fall 2012 Spr 2013 Sum 2013 Fall 2013 Spr 2014 Sum 2014 EET

  12. Wide range radioactive gas concentration detector

    DOE Patents [OSTI]

    Anderson, David F. (Los Alamos, NM)

    1984-01-01T23:59:59.000Z

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  13. Short-Range Nucleon-Nucleon Correlations

    SciTech Connect (OSTI)

    Douglas Higinbotham

    2011-10-01T23:59:59.000Z

    Valence-shell nucleon knock-out experiments, such as 12C(e,e'p)11B, measure less strength then is predicted by independent particle shell model calculations. The theoretical solution to this problem is to include the correlations between the nucleons in the nucleus in the calculations. Motivated by these results, many electron scattering experiments have tried to directly observe these correlations in order to gain new insight into the short-range part of the nucleon-nucleon potential. Unfortunately, many competing mechanisms can cause the same observable final-state as an initial-state correlation, making truly isolating the signal extremely challenging. This paper reviews the recent experimental evidence for short-range correlations, as well as explores the possibility that such correlations are responsible for the EMC effect in the 0.3 < xB < 0.7 deep inelastic scattering ratios.

  14. Short-Range Nucleon-Nucleon Correlations

    SciTech Connect (OSTI)

    Higinbotham, Douglas W. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23601 (United States)

    2011-10-24T23:59:59.000Z

    Valence-shell nucleon knock-out experiments, such as {sup 12}C(e,e'p){sup 11}B, measure less strength then is predicted by independent particle shell model calculations. The theoretical solution to this problem is to include the correlations between the nucleons in the nucleus in the calculations. Motivated by these results, many electron scattering experiments have tried to isolate the signal from these correlations in order to gain new insight into the short-range part of the nucleon-nucleon potential. Unfortunately, many competing mechanisms can cause the same observable final-state as an initial-state correlation, making truly isolating the signal extremely challenging. This paper reviews the recent experimental evidence for short-range correlations, as well as explores the possibility that such correlations are responsible for the EMC effect in the 0.3

  15. Intermediate Range Order and Transport Processes

    E-Print Network [OSTI]

    Harting, Jens

    Simulation Study February 7, 2005 Patrick Pfleiderer ICP, University of Stuttgart in Collaboration: 2 2 21 ),...,,( dt d mV i iNii r rrrF =-= t m ttt ttt t m t ttttt i ii ii i i iii 2 )()( )()( 2-range and responsible for covalent character · obtained from ab initio calculations · time step: 1.6fs 6 2 r C eA r eqq

  16. What Range Herbivores Eat -- and Why

    E-Print Network [OSTI]

    Lyons, Robert K.; Forbes, T. D. A.; Machen, Richard V.

    1999-02-15T23:59:59.000Z

    systems that have the chemicals need- ed to digest it. Cellulose is digested by fermenta- tion. Fermentation requires time and a con- ducive environment in the digestive system *Assistant Professor and Extension Range Specialist; Associate Professor... fermentation can take place. Some monogastrics (like horses, rabbits) have either an enlarged stomach or areas in the large intestine and/or cecum where fermentation can take place. Monogastrics with an enlarged stomach (like the hippopotamus) are called...

  17. Causality and the effective range expansion

    E-Print Network [OSTI]

    H. -W. Hammer; Dean Lee

    2010-07-26T23:59:59.000Z

    We derive the generalization of Wigner's causality bounds and Bethe's integral formula for the effective range parameter to arbitrary dimension and arbitrary angular momentum. We also discuss the impact of these constraints on the separation of low- and high-momentum scales and universality in low-energy scattering. Some of our results were summarized earlier in a letter publication. In this work, we present full derivations and several detailed examples.

  18. Inertial range turbulence in kinetic plasmas

    E-Print Network [OSTI]

    Howes, G G

    2007-01-01T23:59:59.000Z

    The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the ther...

  19. Inertial range turbulence in kinetic plasmas

    E-Print Network [OSTI]

    G. G. Howes

    2007-11-27T23:59:59.000Z

    The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the thermalization of fusion energy in burning plasmas.

  20. Modern testing meets wide range of objectives

    SciTech Connect (OSTI)

    Ehlig-Economides, C.A.; Hegeman, P. (Schlumberger Oilfield Services, Houston, TX (United States)); Clark, G. (Schlumberger Oilfield Services, Aberdeen (United Kingdom))

    1994-08-01T23:59:59.000Z

    Testing sequences in two very different wells illustrate the wide range of objectives that are met with modern testing procedures. The first example is a drill stem test in an exploration well. The second test is in an established producing well. The exploration well test incorporated tubing-conveyed perforating, fluid sampling, production logging, and matrix stimulation to evaluate and properly treat near-well bore damage, as well as to investigate reservoir volume and characterize boundaries. The test on the established producer evaluated whether a workover could remedy lower than expected productivity. Production logging was combined with stationary transient measurements.