Kohl, Arthur L. (Woodland Hills, CA)
1987-07-28
A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediatley above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone.
Kohl, A.L.
1987-07-28
A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediately above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone. 2 figs.
Report on the WORKSHOP ON COMMERCIALIZATION OF BLACK LIQUOR
.3. Gasifier Supplier Perspectives 11 Black Liquor Gasifier Suppliers 12 Biomass Gasifier Suppliers 13 5
Pulsed combustion process for black liquor gasification
Durai-Swamy, K.; Mansour, M.N.; Warren, D.W.
1991-02-01
The objective of this project is to test an energy efficient, innovative black liquor recovery system on an industrial scale. In the MTCI recovery process, black liquor is sprayed directly onto a bed of sodium carbonate solids which is fluidized by steam. Direct contact of the black liquor with hot bed solids promotes high rates of heating and pyrolysis. Residual carbon, which forms as a deposit on the particle surface, is then gasified by reaction with steam. Heat is supplied from pulse combustor resonance tubes which are immersed within the fluid bed. A portion of the gasifier product gas is returned to the pulse combustors to provide the energy requirements of the reactor. Oxidized sulfur species are partially reduced by reaction with the gasifier products, principally carbon monoxide and hydrogen. The reduced sulfur decomposed to solid sodium carbonate and gaseous hydrogen sulfide (H{sub 2}S). Sodium values are recovered by discharging a dry sodium carbonate product from the gasifier. MTCI's indirectly heated gasification technology for black liquor recovery also relies on the scrubbing of H{sub 2}S for product gases to regenerate green liquor for reuse in the mill circuit. Due to concerns relative to the efficiency of sulfur recovery in the MTCI integrated process, an experimental investigation was undertaken to establish performance and design data for this portion of the system.
Definition:Black Liquor | Open Energy Information
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 Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, Alabama (UtilityInstruments IncMississippi: EnergyS A IndustriasNewDefianceBlack Liquor
Proceedings of the black liquor research program review fourth meeting held July 28--30, 1987
Emerson, D. B.; Whitworth, B. A.
1987-10-01
Research programs, presented at the black liquor review meeting are described. Research topics include the following: Cooperative Program in Kraft Recovery; Black Liquor Physical Properties; Viscosity of Strong Black Liquor; Ultrafiltration of Kraft Black Liquor; Molecular Weight Distribution of Kraft Lignin; Black Liquor Droplet Formation Project; Fundamental Studies of Black Liquor Combustion; Black Liquor Combustion Sensors; Flash X-ray Imagining of Black Liquor Sprays; Laser Induced Fluorescence For Process Control In The Pulp and Paper Industry; Recovery Boiler Optimization; Black Liquor Gasification and Use of the Products in Combined-Cycle Cogeneration; Black Liquor Steam Plasma Automization; The B and W Pyrosonic 2000R System; Monsteras Boiler Control System; and Cooperative Program Project Reviews. Individual projects are processed separately for the data bases.
Black Liquor Gasification Process Review and Status Update
Brown, C.
1993-01-01
After more than two decades of research and development, black liquor gasification is poised to become a commercial reality in the 90's. Several promising developments are underway in North America and Europe. In fact, all major recovery boiler...
Drum drying of black liquor using superheated steam impinging jets
Shiravi, A.H.; Mujumdar, A.S.; Kubes, G.J. [McGill Univ., Montreal, Quebec (Canada)
1997-05-01
A novel drum dryer for black liquor utilizing multiple impinging jets of superheated steam was designed and built to evaluate the performance characteristics and effects of various operating parameters thereon. Appropriate ranges of parameters such as steam jet temperature and velocity were examined experimentally to quantify the optimal operating conditions for the formation of black liquor film on the drum surface as well as the drying kinetics.
Black liquor gasification phase 2D final report
Kohl, A.L.; Stewart, A.E.
1988-06-01
This report covers work conducted by Rockwell International under Amendment 5 to Subcontract STR/DOE-12 of Cooperative Agreement DE-AC-05-80CS40341 between St. Regis Corporation (now Champion International) and the Department of Energy (DOE). The work has been designated Phase 2D of the overall program to differentiate it from prior work under the same subcontract. The overall program is aimed at demonstrating the feasibility of and providing design data for the Rockwell process for gasifying Kraft black liquor. In this process, concentrated black liquor is converted into low-Btu fuel gas and reduced melt by reaction with air in a specially designed gasification reactor.
Advancement of High Temperature Black Liquor Gasification Technology
Craig Brown; Ingvar Landalv; Ragnar Stare; Jerry Yuan; Nikolai DeMartini; Nasser Ashgriz
2008-03-31
Weyerhaeuser operates the world's only commercial high-temperature black liquor gasifier at its pulp mill in New Bern, NC. The unit was started-up in December 1996 and currently processes about 15% of the mill's black liquor. Weyerhaeuser, Chemrec AB (the gasifier technology developer), and the U.S. Department of Energy recognized that the long-term, continuous operation of the New Bern gasifier offered a unique opportunity to advance the state of high temperature black liquor gasification toward the commercial-scale pressurized O2-blown gasification technology needed as a foundation for the Forest Products Bio-Refinery of the future. Weyerhaeuser along with its subcontracting partners submitted a proposal in response to the 2004 joint USDOE and USDA solicitation - 'Biomass Research and Development Initiative'. The Weyerhaeuser project 'Advancement of High Temperature Black Liquor Gasification' was awarded USDOE Cooperative Agreement DE-FC26-04NT42259 in November 2004. The overall goal of the DOE sponsored project was to utilize the Chemrec{trademark} black liquor gasification facility at New Bern as a test bed for advancing the development status of molten phase black liquor gasification. In particular, project tasks were directed at improvements to process performance and reliability. The effort featured the development and validation of advanced CFD modeling tools and the application of these tools to direct burner technology modifications. The project also focused on gaining a fundamental understanding and developing practical solutions to address condensate and green liquor scaling issues, and process integration issues related to gasifier dregs and product gas scrubbing. The Project was conducted in two phases with a review point between the phases. Weyerhaeuser pulled together a team of collaborators to undertake these tasks. Chemrec AB, the technology supplier, was intimately involved in most tasks, and focused primarily on the design, specification and procurement of facility upgrades. Chemrec AB is also operating a pressurized, O2-blown gasifier pilot facility in Piteaa, Sweden. There was an exchange of knowledge with the pressurized projects including utilization of the experimental results from facilities in Piteaa, Sweden. Resources at the Georgia Tech Research Corporation (GTRC, a.k.a., the Institute of Paper Science and Technology) were employed primarily to conduct the fundamental investigations on scaling and plugging mechanisms and characterization of green liquor dregs. The project also tapped GTRC expertise in the development of the critical underlying black liquor gasification rate subroutines employed in the CFD code. The actual CFD code development and application was undertaken by Process Simulation, Ltd (PSL) and Simulent, Ltd. PSL focused on the overall integrated gasifier CFD code, while Simulent focused on modeling the black liquor nozzle and description of the black liquor spray. For nozzle development and testing Chemrec collaborated with ETC (Energy Technology Centre) in Piteae utilizing their test facility for nozzle spray investigation. GTI (Gas Technology Institute), Des Plains, IL supported the team with advanced gas analysis equipment during the gasifier test period in June 2005.
Fricke, A.L.; Zaman, A.A.
1998-05-01
The overall objective of the program was to develop correlations to predict physical properties within requirements of engineering precision from a knowledge of pulping conditions and of kraft black liquor composition, if possible. These correlations were to include those relating thermodynamic properties to pulping conditions and liquor composition. The basic premise upon which the research was based is the premise that black liquor behaves as a polymer solution. This premise has proven to be true, and has been used successfully in developing data reduction methods and in interpreting results. A three phase effort involving pulping, analysis of liquor composition, and measurement of liquor properties was conducted.
Li, Mo
MOLTEN SALT CORROSION OF SUPERHEATERS IN BLACK LIQUOR RECOVERY BOILERS John Bohling, University Goodman Introduction In the papermaking industry, black liquor recovery boilers burn black liquor into the superheater region of the boiler, where the salt-deposit, or smelt, forms a scale on the superheater tubes.1
Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer
Kevin Whitty
2007-06-30
University of Utah's project entitled 'Investigation of Fuel Chemistry and Bed Performance in a Fluidized Bed Black Liquor Steam Reformer' (DOE Cooperative Agreement DE-FC26-02NT41490) was developed in response to a solicitation released by the U.S. Department of Energy in December 2001, requesting proposals for projects targeted towards black liquor/biomass gasification technology support research and development. Specifically, the solicitation was seeking projects that would provide technical support for Department of Energy supported black liquor and biomass gasification demonstration projects under development at the time.
Fricke, A.L.; Zaman, A.A.; Stoy, M.O.; Schmidl, G.W.; Dong, D.J.; Speck, B.
1998-04-01
A wide variety of experimental techniques have been used in this work, and many of these have been developed completely or improved significantly in the course of the research done during this program. Therefore, it is appropriate to describe these techniques in detail as a reference for future workers so that the techniques can be used in future work with little additional effort or so that the results reported from this program can be compared better with future results from other work. In many cases, the techniques described are for specific analytical instruments. It is recognized that these may be superseded by future developments and improvements in instrumentation if a complete description of techniques used successfully in the past on other instrumentation is available. The total pulping and liquor preparation research work performed included chip and white liquor preparation, digestion, pulp washing, liquor and wash recovery, liquor sampling, weak liquor concentration in two steps to about 45--50% solids with an intermediate soap skimming at about 140F and 27--30% solids, determination of pulp yield and Kappa number, determination of total liquor solids, and a check on the total material balance for pulping. All other research was performed either on a sample of the weak black liquor (the combined black liquor and washes from the digester) or on the skimmed liquor that had been concentrated.
Effect of pulsation on black liquor gasification. Final report
Zinn, B.T.; Jagoda, J.; Jeong, H.; Kushari, A.; Rosen, L.J.
1998-12-01
Pyrolysis is an endothermic process. The heat of reaction is provided either by partial combustion of the waste or by heat transfer from an external combustion process. In one proposed system black liquor is pyrolized in a fluidized bed to which heat is added through a series of pulse combustor tail pipes submerged in the bed material. This system appears promising because of the relatively high heat transfer in pulse combustors and in fluidized beds. Other advantages of pulse combustors are discussed elsewhere. The process is, however, only economically viable if a part of the pyrolysis products can be used to fire the pulse combustors. The overall goals of this study were to determine: (1) which is the limiting heat transfer rate in the process of transferring heat from the hot combustion products to the pipe, through the pipe, from the tail pipe to the bed and through the bed; i.e., whether increased heat transfer within the pulse combustor will significantly increase the overall heat transfer rate; (2) whether the heat transfer benefits of the pulse combustor can be utilized while maintaining the temperature in the bed within the narrow temperature range required by the process without generating hot spots in the bed; and (3) whether the fuel gas produced during the gasification process can be used to efficiently fire the pulse combustor.
BIOMASS AND BLACK LIQUOR GASIFIER/GAS TURBINE COGENERATION AT PULP AND PAPER MILLS
/steamturbinetechnologies. Gasification technologies under development will allow biomass-derived fuels to be usedto fuel gasturbine gasification. The use of biomass fuels with gas turbines could transform a typical pulp mill from a netBIOMASS AND BLACK LIQUOR GASIFIER/GAS TURBINE COGENERATION AT PULP AND PAPER MILLS ERIC D. LARSON
Kevin Whitty
2008-06-30
The University of Utah's project 'Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment' (U.S. DOE Cooperative Agreement DE-FC26-04NT42261) was a response to U.S. DOE/NETL solicitation DE-PS36-04GO94002, 'Biomass Research and Development Initiative' Topical Area 4-Kraft Black Liquor Gasification. The project began September 30, 2004. The objective of the project was to improve the understanding of black liquor conversion in high pressure, high temperature reactors that gasify liquor through partial oxidation with either air or oxygen. The physical and chemical characteristics of both the gas and condensed phase were to be studied over the entire range of liquor conversion, and the rates and mechanisms of processes responsible for converting the liquor to its final smelt and syngas products were to be investigated. This would be accomplished by combining fundamental, lab-scale experiments with measurements taken using a new semi-pilot scale pressurized entrained-flow gasifier. As a result of insufficient availability of funds and changes in priority within the Office of Biomass Programs of the U.S. Department of Energy, the research program was terminated in its second year. In total, only half of the budgeted funding was made available for the program, and most of this was used during the first year for construction of the experimental systems to be used in the program. This had a severe impact on the program. As a consequence, most of the planned research was unable to be performed. Only studies that relied on computational modeling or existing experimental facilities started early enough to deliver useful results by the time to program was terminated Over the course of the program, small scale (approx. 1 ton/day) entrained-flow gasifier was designed and installed at the University of Utah's off-campus Industrial Combustion and Gasification Research Facility. The system is designed to operate at pressures as high as 32 atmospheres, and at temperatures as high as 1500 C (2730 F). Total black liquor processing capacity under pressurized, oxygen-blown conditions should be in excess of 1 ton black liquor solids per day. Many sampling ports along the conversion section of the system will allow detailed analysis of the environment in the gasifier under industrially representative conditions. Construction was mostly completed before the program was terminated, but resources were insufficient to operate the system. A system for characterizing black liquor sprays in hot environments was designed and constructed. Silhouettes of black liquor sprays formed by injection of black liquor through a twin fluid (liquor and atomizing air) nozzle were videoed with a high-speed camera, and the resulting images were analyzed to identify overall characteristics of the spray and droplet formation mechanisms. The efficiency of liquor atomization was better when the liquor was injected through the center channel of the nozzle, with atomizing air being introduced in the annulus around the center channel, than when the liquor and air feed channels were reversed. Atomizing efficiency and spray angle increased with atomizing air pressure up to a point, beyond which additional atomizing air pressure had little effect. Analysis of the spray patterns indicates that two classifications of droplets are present, a finely dispersed 'mist' of very small droplets and much larger ligaments of liquor that form at the injector tip and form one or more relatively large droplets. This ligament and subsequent large droplet formation suggests that it will be challenging to obtain a narrow distribution of droplet sizes when using an injector of this design. A model for simulating liquor spray and droplet formation was developed by Simulent, Inc. of Toronto. The model was able to predict performance when spraying water that closely matched the vendor specifications. Simulation of liquor spray indicates that droplets on the order 200-300 microns can be expected, and that higher liquor flow will result in be
PERFORMANCE OF BLACK LIQUOR GASIFIER/GAS TURBINE COMBINED CYCLE COGENERATION IN mE KRAFT PULP
,and otherregions with low wood production costs and relatively low per-capita levels of paper use. The majority,and capital cost benefits for kraft mills. Several companie.~arepursuingcon-urercializationof black liquor
Effect of pulsations on black liquor gasification. Progress report, July--September 1995
Kushari, A.; Jeong, H.; Jagoda, J.I.; Zinn, B.T.
1995-12-31
The objective of this study is to investigate the use of pulse combustion to provide the energy required for the endothermic gasification of black liquor in a fluidized bed. In this process it is critical that the temperature remain in the small window above the gasification temperature but below the smelting temperature of the inorganic salts in the black liquor. Pulse combustors have been shown to have high heat transfer rates between the hot combustion products and the combustor tailpipe. Similarly, fluidized beds have high heat transfer rates within the bed itself, promoting temperature uniformity throughout. Typical analysis of the gasified black liquor shows there is a large percentage of combustible gases in the products of the gasification process (approximately 70%). The potential exists, therefore, for using this fuel mixture to fire the pulse combustor. This makes the entire process more efficient and may be necessary to make it economically feasible. The overall goals of this study are to determine (1) which is the limiting heat transfer rate in the process of transferring the heat from the hot combustion products to the pipe, through the pipe, from the tailpipe to the bed and then throughout the bed; i.e., whether increased heat transfer within the pulse combustor will significantly increase the overall heat transfer rate; (2) whether the temperature distribution in the bed can be maintained within the narrow temperature range required by the process without generating hot spots in the bed even if the heat transfer from the pulse combustor is significantly increased; and (3) whether the fuel gas produced during the gasification process can be used to efficiently fire the pulse combustor.
Cracking and Corrosion of Composite Tubes in Black Liquor Recovery Boiler Primary Air Ports
Keiser, James R.; Singbeil, Douglas L.; Sarma, Gorti B.; Kish, Joseph R.; Yuan, Jerry; Frederick, Laurie A.; Choudhury, Kimberly A.; Gorog, J. Peter; Jetté, Francois R.; Hubbard, Camden R.; Swindeman, Robert W.; Singh, Prett M.; Maziasz, Phillip J.
2006-10-01
Black liquor recovery boilers are an essential part of kraft mills. Their design and operating procedures have changed over time with the goal of providing improved boiler performance. These performance improvements are frequently associated with an increase in heat flux and/or operating temperature with a subsequent increase in the demand on structural materials associated with operation at higher temperatures and/or in more corrosive environments. Improvements in structural materials have therefore been required. In most cases the alternate materials have provided acceptable solutions. However, in some cases the alternate materials have solved the original problem but introduced new issues. This report addresses the performance of materials in the tubes forming primary air port openings and, particularly, the problems associated with use of stainless steel clad carbon steel tubes and the solutions that have been identified.
Southards, W.T.; Clement, J.L.; McIlroy, R.A.; Tharp, M.R.; Verrill, C.L.; Wessell, R.A.
1995-11-01
This project is a multiple-phase effort to develop technologies to improve high-solids black liquor firing in pulp mill recovery boilers. The principal means to this end is to construct and operate a pilot-scale recovery furnace simulator (RFS) in which these technologies can be tested. The Phase 1 objectives are to prepare a preliminary design for the RFS, delineate a project concept for evaluating candidate technologies, establish industrial partners, and report the results. Phase 1 addressed the objectives with seven tasks: Develop a preliminary design of the RFS; estimate the detailed design and construction costs of the RFS and the balance of the project; identify interested parties in the paper industry and key suppliers; plan the Phase 2 and Phase 3 tests to characterize the RFS; evaluate the economic justification for high-solids firing deployment in the industry; evaluate high-solids black liquor property data to support the RFS design; manage the project and reporting results, which included planning the future program direction.
Hasan Jameel, North Carolina State University; Adrianna Kirkman, North Carolina State University; Ravi Chandran,Thermochem Recovery International Brian Turk Research Triangle Institute; Brian Green, Research Triangle Institute
2010-01-27
As many of the recovery boilers and other pieces of large capital equipment of U.S. pulp mills are nearing the end of their useful life, the pulp and paper industry will soon need to make long-term investments in new technologies. The ability to install integrated, complete systems that are highly efficient will impact the industry’s energy use for decades to come. Developing a process for these new systems is key to the adoption of state-of-the-art technologies in the Forest Products industry. This project defined an integrated process model that combines mini-sulfide sulfite anthraquinone (MSS-AQ) pulping and black liquor gasification with a proprietary desulfurization process developed by the Research Triangle Institute. Black liquor gasification is an emerging technology that enables the use of MSS-AQ pulping, which results in higher yield, lower bleaching cost, lower sulfur emissions, and the elimination of causticization requirements. The recently developed gas cleanup/absorber technology can clean the product gas to a state suitable for use in a gas turbine and also regenerate the pulping chemicals needed to for the MSS-AQ pulping process. The combination of three advanced technologies into an integrated design will enable the pulping industry to achieve a new level of efficiency, environmental performance, and cost savings. Because the three technologies are complimentary, their adoption as a streamlined package will ensure their ability to deliver maximum energy and cost savings benefits. The process models developed by this project will enable the successful integration of new technologies into the next generation of chemical pulping mills. When compared to the Kraft reference pulp, the MSS-AQ procedures produced pulps with a 10-15 % yield benefit and the ISO brightness was 1.5-2 times greater. The pulp refined little easier and had a slightly lower apparent sheet density (In both the cases). At similar levels of tear index the MSS-AQ pulps also produced a comparable tensile and burst index pulps. Product gas composition determined using computer simulations The results demonstrate that RVS-1 can effectively remove > 99.8% of the H2S present in simulated synthesis gas generated from the gasification of black liquor. This level of sulfur removal was consistent over simulated synthesis gas mixtures that contained from 6 to 9.5 vol % H2S.A significant amount of the sulfur in the simulated syngas was recovered as SO2 during regeneration. The average recovery of sulfur as SO2 was about 75%. Because these are first cycle results, this sulfur recovery is expected to improve. Developed WINGems model of the process.The total decrease in variable operating costs for the BLG process compared to the HERB was in excess of $6,200,000 per year for a mill producing 350,000 tons of pulp per year. This represents a decrease in operating cost of about $17.7/ton of oven dry pulp produced. There will be additional savings in labor and maintenance cost that has not been taken into account. The capital cost for the MSSAQ based gasifier system was estimated at $164,000,000, which is comparable to a High Efficiency Recovery Boiler. The return on investment was estimated at 4%. A gasifier replacement cannot be justified on its own, however if the recovery boiler needs to be replaced the MSSAQ gasifier system shows significantly higher savings. Before black liquor based gasifer technology can be commercialized more work is necessary. The recovery of the absorbed sulfur in the absorbent as sulfur dioxide is only 75%. This needs to be greater than 90% for economical operation. It has been suggested that as the number of cycles is increased the sulfur dioxide recovery might improve. Further research is necessary. Even though a significant amount of work has been done on a pilot scale gasifiers using liquors containing sulfur, both at low and high temperatures the lack of a commercial unit is an impediment to the implementation of the MSSAQ technology. The implementation of a commercial unit needs to be facilated before the benefits of
Big Island Demonstration Project – Black Liquor
Broader source: Energy.gov [DOE]
This fact sheet summarizes a U.S. Department of Energy Biomass Program research and development project.
Highly Energy Efficient Directed Green Liquor Utilization (D...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Highly Energy Efficient Directed Green Liquor Utilization (D-GLU) Pulping Highly Energy Efficient Directed Green Liquor Utilization (D-GLU) Pulping This factsheet describes a...
Recovery of sugars from ionic liquid biomass liquor by solvent...
Office of Scientific and Technical Information (OSTI)
Patent: Recovery of sugars from ionic liquid biomass liquor by solvent extraction Citation Details In-Document Search Title: Recovery of sugars from ionic liquid biomass liquor by...
LIQUOR POLICY University Policy No.: AD2400
Victoria, University of
Page 1 LIQUOR POLICY University Policy No.: AD2400 Classification: Administration Approving and Appendices: Procedures Associated with the University Liquor Policy Appendix ,,A - Licensed Establishments on University Property PURPOSE 1.00 The purpose of this policy is to: set out requirements regarding
Environmentalism and the Politics of Equity: Emergent Trends in the Black Community
Bullard, Robert; Wright, Beverly Hendrix
1987-01-01
. That is, the abili ty of the tobacco giants to exercise their constitutional rights. Tobacco and liquor companies provide generous contributions to black "causes" and buy considerable advertizing space and time in black newspapers and. magazines. Black... ENVIRONMENTALISM AND THE POLITICS OF EQUITY: EMERGENT TRENDS IN THE BLACK COMMUNITY· Robert Bullard University oj Tennessee-Knoxville Beverly Hendrix Wright Universityo fNew Orleans Mid-American Review of Sociology, 1987, Vol. XII, No. 2:21-38 The environmental...
Use of sulfide-containing liquors for removing mercury from flue gases
Nolan, Paul S. (North Canton, OH); Downs, William (Alliance, OH); Bailey, Ralph T. (Uniontown, OH); Vecci, Stanley J. (Alliance, OH)
2003-01-01
A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.
Use of sulfide-containing liquors for removing mercury from flue gases
Nolan, Paul S.; Downs, William; Bailey, Ralph T.; Vecci, Stanley J.
2006-05-02
A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.
Griffith, William Louis; Compere, Alicia Lucille; Leitten, Jr., Carl Frederick
2010-04-20
A method for separating carbohydrates from pulping liquors includes the steps of providing a wood pulping or wood or biomass hydrolysis pulping liquor having lignin therein, and mixing the liquor with an acid or a gas which forms an acid upon contact with water to initiate precipitation of carbohydrate to begin formation of a precipitate. During precipitation, at least one long chain carboxylated carbohydrate and at least one cationic polymer, such as a polyamine or polyimine are added, wherein the precipitate aggregates into larger precipitate structures. Carbohydrate gel precipitates are then selectively removed from the larger precipitate structures. The method process yields both a carbohydrate precipitate and a high purity lignin.
Li, Jian (Marietta, GA); Chai, Xin Sheng (Atlanta, GA); Zhu, Junyoung (Marietta, GA)
2008-06-24
The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.
Fisher, F.D.
1995-03-30
Plutonium-bearing liquors, including ANL scrap liquors, will be used for development and demonstration of a vertical calciner direct denitration process for conversion of those liquors to stable, storable PuO{sub 2}-rich solids. This test plan is to test with non-radioactive stand-in materials to demonstrate adequate performance of the vertical calciner and ancillary equipment.
Oil palm vegetation liquor: a new source of phenolic bioactives Ravigadevi Sambanthamurthi1
Sinskey, Anthony J.
Oil palm vegetation liquor: a new source of phenolic bioactives Ravigadevi Sambanthamurthi1 *, Yew , Krishnan Subramaniam5 , Soon-Sen Leow1 , Kenneth C. Hayes6 and Mohd Basri Wahid1 1 Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang Selangor, Malaysia 2 Malaysian Palm Oil
Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor
Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)
1996-11-05
Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration.
Novel Pulping Technology: Directed Green Liquor Utilization (D-GLU) Pulping
Lucian A. Lucia
2005-11-15
The general objectives of this new project are the same as those described in the original proposal. Conventional kraft pulping technologies will be modified for significant improvements in pulp production, such as strength, bleachability, and yield by using green liquor, a naturally high, kraft mill-derived sulfidity source. Although split white liquor sulfidity and other high sulfidity procedures have the promise of addressing several of the latter important economic needs of pulp mills, they require considerable engineering/capital retrofits, redesigned production methods, and thus add to overall mill expenditures. Green liquor use, however, possesses the required high sulfidity to obtain in general the benefits attributable to higher sulfidity cooking, without the required capital constraints for implementation. Before introduction of green liquor in our industrial operations, a stronger understanding of its fundamental chemical interaction with the lignin and carbohydrates in US hardwood and softwoods must be obtained. In addition, its effect on bleachability, enhancement of pulp properties, and influence on the overall energy and recovery of the mill requires further exploration before the process witnesses widespread mill use in North America. Thus, proof of principle will be accomplished in this work and the consequent effect of green liquor and other high sulfide sources on the pulping and bleaching operations will be explored for US kraft mills. The first year of this project will generate the pertinent information to validate its ability for implementation in US pulping operations, whereas year two will continue this work while proceeding to analyze pulp bleachability and final pulp/paper properties and develop a general economic and feasibility analysis for its eventual implementation in North America.
Li, Xin
1999-01-01
concentrated by evaporation to about 40% total solids. Lactose was crystallized and separated from the remaining liquid. An HPLC method was employed to determine the concentration of taurine in milk, whey, permeate and mother liquor. The concentration...
Emerging energy-efficient industrial technologies
2000-01-01
1998. “Black Liquor Gasifier/Gas Turbine Cogeneration. ”Black Liquor and Biomass Gasifier/Gas Turbine Technology. ”of Black Liquor Gasifier/Combined Cycle Technology
Jing, Yaqi; Meng, Qinghao, E-mail: qh-meng@tju.edu.cn; Qi, Peifeng; Zeng, Ming; Li, Wei; Ma, Shugen [Tianjin Key Laboratory of Process Measurement and Control, Institute of Robotics and Autonomous Systems, School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)] [Tianjin Key Laboratory of Process Measurement and Control, Institute of Robotics and Autonomous Systems, School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)
2014-05-15
An electronic nose (e-nose) was designed to classify Chinese liquors of the same aroma style. A new method of feature reduction which combined feature selection with feature extraction was proposed. Feature selection method used 8 feature-selection algorithms based on information theory and reduced the dimension of the feature space to 41. Kernel entropy component analysis was introduced into the e-nose system as a feature extraction method and the dimension of feature space was reduced to 12. Classification of Chinese liquors was performed by using back propagation artificial neural network (BP-ANN), linear discrimination analysis (LDA), and a multi-linear classifier. The classification rate of the multi-linear classifier was 97.22%, which was higher than LDA and BP-ANN. Finally the classification of Chinese liquors according to their raw materials and geographical origins was performed using the proposed multi-linear classifier and classification rate was 98.75% and 100%, respectively.
HIGHLY ENERGY EFFICIENT D-GLU (DIRECTED-GREEN LIQ-UOR UTILIZATION) PULPING
Lucia, Lucian A
2013-04-19
Purpose: The purpose of the project was to retrofit the front end (pulp house) of a commercial kraft pulping mill to accommodate a mill green liquor (GL) impregna-tion/soak/exposure and accrue downstream physical and chemical benefits while prin-cipally reducing the energy footprint of the mill. A major player in the mill contrib-uting to excessive energy costs is the lime kiln. The project was intended to offload the energy (oil or natural gas) demands of the kiln by by-passing the causticization/slaking site in the recovery area and directly using green liquor as a pulping medium for wood. Scope: The project was run in two distinct, yet mutually compatible, phases: Phase 1 was the pre-commercial or laboratory phase in which NC State University and the Insti-tute of Paper Science and Technology (at the Georgia Institute of Technology) ran the pulping and associated experiments, while Phase 2 was the mill scale trial. The first tri-al was run at the now defunct Evergreen Pulp Mill in Samoa, CA and lead to a partial retrofit of the mill that was not completed because it went bankrupt and the work was no longer the low-hanging fruit on the tree for the new management. The second trial was run at the MeadWestvaco Pulp Mill in Evedale, TX which for all intents and pur-poses was a success. They were able to fully retrofit the mill, ran the trial, studied the pulp properties, and gave us conclusions.
Bench-scale Kinetics Study of Mercury Reactions in FGD Liquors
Gary Blythe; John Currie; David DeBerry
2008-03-31
This document is the final report for Cooperative Agreement DE-FC26-04NT42314, 'Kinetics Study of Mercury Reactions in FGD Liquors'. The project was co-funded by the U.S. DOE National Energy Technology Laboratory and EPRI. The objective of the project has been to determine the mechanisms and kinetics of the aqueous reactions of mercury absorbed by wet flue gas desulfurization (FGD) systems, and develop a kinetics model to predict mercury reactions in wet FGD systems. The model may be used to determine optimum wet FGD design and operating conditions to maximize mercury capture in wet FGD systems. Initially, a series of bench-top, liquid-phase reactor tests were conducted and mercury species concentrations were measured by UV/visible light spectroscopy to determine reactant and byproduct concentrations over time. Other measurement methods, such as atomic absorption, were used to measure concentrations of vapor-phase elemental mercury, that cannot be measured by UV/visible light spectroscopy. Next, a series of bench-scale wet FGD simulation tests were conducted. Because of the significant effects of sulfite concentration on mercury re-emission rates, new methods were developed for operating and controlling the bench-scale FGD experiments. Approximately 140 bench-scale wet FGD tests were conducted and several unusual and pertinent effects of process chemistry on mercury re-emissions were identified and characterized. These data have been used to develop an empirically adjusted, theoretically based kinetics model to predict mercury species reactions in wet FGD systems. The model has been verified in tests conducted with the bench-scale wet FGD system, where both gas-phase and liquid-phase mercury concentrations were measured to determine if the model accurately predicts the tendency for mercury re-emissions. This report presents and discusses results from the initial laboratory kinetics measurements, the bench-scale wet FGD tests, and the kinetics modeling efforts.
Randolph, A.D.; Mukhopadhyay, S.; Unrau, E.
1994-12-31
During this quarterly period, an experimental investigation was performed to study the precipitation kinetics and hydrolysis characteristics of calcium imido disulfonate crystals (CaADS). The CaADS crystals were precipitated by a metathetical reaction of lime, supplied by Dravo Lime Co., with flue gas desulfurization (FGD) scrubber waste liquor. Before approaching for the continuous Double Draw-Off (DDO) crystallization studies, the influence of a Dravo lime slurry on the precipitation characteristics of N-S compounds will be established. A series of N-S compound batch crystallization studies were completed in a wide range of pH (7.0--9.0), and the influence of pH on the amount of lime required, as well as the amount of precipitate obtained, was investigated. Although the amount of precipitate increased with increase in solution pH, the safe or optimum pH for the precipitation of CaADS lies in the vicinity of 8.2 to 8.3. For studying the crystallization characteristics of CaADS crystals, a bench scale 7.0 liter DDO crystallizer was built. DDO crystallizer is found to be superior compared to Mixed Suspension Mixed Product Removal (MSMPR) crystallizer. The precipitated crystals were analyzed for elemental composition by chemical analysis. The crystals were also examined under optical microscope for their morphological features. The present studies confirmed our prediction that N-S compounds in the waste liquor can be precipitated by a reaction with lime slurry. The precipitated crystals were mostly calcium imido disulfonate.
Martin, Nathan; Anglani, N.; Einstein, D.; Khrushch, M.; Worrell, E.; Price, L.K.
2000-01-01
July, 1998. Black Liquor Gasifier/Gas Turbine Cogeneration.Economics of Black Liquor Gasifier/Gas Turbine CogenerationEconomics of Black Liquor Gasifier/Gas Turbine Cogeneration
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HAB Packet HanfordDOEDanielDe novo Design ofDefects LeadDel Black Del
Sacrificial Protective Coating Materials that can be Regenerated...
Broader source: Energy.gov (indexed) [DOE]
2015: Demonstrate black liquor treatment process with less than 10% drop in flux after coating of membrane module February 29, 2016: Demonstrate black liquor treatment process...
Chagnes, A.; Cote, G.; Courtaud, B.; Thiry, J.
2008-07-01
The present work is focussed on the chemical degradation of Alamine 336-tridecanol-n-dodecane solvent which used in the recovery of uranium by solvent extraction. Degradation occurs due to the presence of vanadium(V), an oxidant, in the feed solution. After a brief overview of the chemistry of vanadium, the kinetics of degradation of the solvent when contacted with acidic sulfate leach liquor was investigated and interpreted by the Michelis-Menten mechanism. GCMS analyses evidenced the presence of tridecanoic acid and dioctylamine as degradation products. A mechanism of degradation is discussed. (authors)
Laura Ferrarese; David Merritt
2002-06-13
After a brief historical introduction, we summarize current efforts and accomplishments in the study of supermassive black holes.
Office of Energy Efficiency and Renewable Energy (EERE)
Black Pine Engineering is commercializing a disruptive technology in the turbomachinery industry. Using a patented woven composite construction, Black Pine Engineering can make turbomachines (turbines, compressors) that are cheaper and lighter than competing technologies. Using this technology, Black Pine Engineering will sell turbo-compressors which solve the problem of wasted steam in geothermal power plants.
Magnetized static black Saturn
Stoytcho S. Yazadjiev
2008-02-06
We construct a new static solution to the 5D Einstein-Maxwell equations describing a static black hole surrounded by a non-rotating dipole black ring. The configuration is kept in equilibrium by an external magnetic field interacting with the dipole charge of the black ring. The properties of the black Saturn-like configuration are studied and the basic physical quantities are calculated. The solution demonstrates 2-fold continuous non-uniqueness of the 5D magnetized static neutral black objects for fixed total mass and Melvin background.
Henriette Elvang; Maria J. Rodriguez
2008-01-25
We present detailed physics analyses of two different 4+1-dimensional asymptotically flat vacuum black hole solutions with spin in two independent planes: the doubly spinning black ring and the bicycling black ring system ("bi-rings"). The latter is a new solution describing two concentric orthogonal rotating black rings which we construct using the inverse scattering technique. We focus particularly on extremal zero-temperature limits of the solutions. We construct the phase diagram of currently known zero-temperature vacuum black hole solutions with a single event horizon, and discuss the non-uniqueness introduced by more exotic black hole configurations such as bi-rings and multi-ring saturns.
Elvang, Henriette
2008-01-01
We present detailed physics analyses of two different 4+1-dimensional asymptotically flat vacuum black hole solutions with spin in two independent planes: the doubly spinning black ring and the bicycling black ring system ("bi-rings"). The latter is a new solution describing two concentric orthogonal rotating black rings which we construct using the inverse scattering technique. We focus particularly on extremal zero-temperature limits of the solutions. Such limits exist for both types of solutions; for the bi-rings it is obtained when the two rings drag each other to extremality through the effect of gravitational frame-dragging. We construct the phase diagram of currently known zero-temperature vacuum black hole solutions with a single event horizon, and discuss the non-uniqueness introduced by more exotic black hole configurations such as bi-rings and multi-ring saturns.
Broader source: Energy.gov [DOE]
Black History Month is an annual celebration of achievements by black Americans and a time for recognizing the central role of African Americans in U.S. history. The event grew out of “Negro History Week,” created by historian Carter G. Woodson and other prominent African Americans. Other countries around the world, including Canada and the United Kingdom, also devote a month to celebrating black history.
Begelman, Mitchell C
2014-01-01
I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of black hole accretion depend on interactions between the relatively simple black-hole spacetime and complex radiation, plasma and magnetohydrodynamical processes in the surrounding gas. I will show how transient accretion processes could provide clues to these interactions. Larger global magnetohydrodynamic simulations as well as simulations incorporating plasma microphysics and full radiation hydrodynamics will be needed to unravel some of the current mysteries of black hole accretion.
B. Kleihaus; J. Kunz
2000-12-20
We construct stationary black holes in SU(2) Einstein-Yang-Mills theory, which carry angular momentum and electric charge. Possessing non-trivial non-abelian magnetic fields outside their regular event horizon, they represent non-perturbative rotating hairy black holes.
Valeri P. Frolov; Andrei V. Frolov
2014-12-30
We discuss a solution of the Einstein equations, obtained by gluing the external Kerr metric and the internal Weyl metric, describing an axisymmetric static vacuum distorted black hole. These metrics are glued at the null surfaces representing their horizons. For this purpose we use the formalism of massive thin null shells. The corresponding solution is called a "hybrid" black hole. The massive null shell has an angular momentum which is the origin of the rotation of the external Kerr spacetime. At the same time, the shell distorts the geometry inside the horizon. The inner geometry of the "hybrid" black hole coincides with the geometry of the interior of a non-rotating Weyl-distorted black hole. Properties of the "hybrid" black holes are briefly discussed.
Kong, Lingbo
2014-01-01
economics of black liquor gasifier/gas turbine cogenerationblack liquor and biomass gasifier/gas turbine technology".entrained flow booster gasifier in New Bern, North Carolina;
PURDUE UNIVERSITY BLACK CULTURAL CENTER
Pittendrigh, Barry
traveled to Detroit, Michigan to study our fall research theme, " Black Detroit: The History, Movement
Black Holes and Galaxy Evolution
David Merritt
1999-10-29
Supermassive binary black holes and their influence on the structure and evolution of galaxies is reviewed.
Black Holes In Astronomy Black Holes In Astronomy
Wagner, Stephan
Black Hole horizon static limit ergosphere radiation magnetic fields jet jet #12;Black-hole accretion with a central bulge. #12;Click to edit Master text styles Second level Third level Fourth level Fifth level Jets and lobes of Cygnus A Carilli et al. Supermassive black holes are the most powerful engines in the Universe
The renaissance of black phosphorus
Ling, Xi
One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from ...
Mei, Jianwei
2010-10-12
. . . . . . . . . 21 1. Solutions in Four Dimensions . . . . . . . . . . . . . . 22 2. Solutions in Higher Dimensions . . . . . . . . . . . . . 27 C. Black Hole Solutions in Supergravity Theories . . . . . . . 30 D. Plebanski-Demianski Type Solutions in d = 5... is to discuss the construction of new black hole solutions and the calculation of the black hole entropy. In Chapter II, we shall re- port some new black hole solutions that we have found during the past few years [21, 22, 23] and we will discuss some...
Bryan Webber
2006-04-06
In theories with large extra dimensions and TeV-scale gravity, black holes are copiously produced in particle collisions at energies well above the Planck scale. I briefly review some recent work on the phenomenology of this process, with emphasis on theoretical uncertainties and possible strategies for measuring the number of extra dimensions.
M. B. Altaie
2001-05-07
In this paper we follow a new approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field red-shifts the frequency modes of the vacuum, a condition on the minimum stregth of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwartzchid black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created. Using this regional upper limit, and considering particle creation by black holes as a consequence of the Casimir effect, with the assumption that the created quanta are to be added to the initial energy, we deduce a natural power law for the development of the event horizon, and consequently a logarithmic law for the area spectrum of an inflating black hole. Application of the results on a cosmological model shows that if we start with a Planck-dimensional black hole, then through the process of particle creation we end up with a universe having the presently estimated critical density. Such a universe will be in a state of eternal inflation.
Statistical Mechanics of Black Holes
B. Harms; Y. Leblanc
1992-05-11
We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black hole decay and of quantum coherence are also addressed.
Identification of Astrophysical Black Holes
Sandip K. Chakrabarti
1998-03-19
Black holes are by definition black, and therefore cannot be directly observed by using electromagnetic radiations. Convincing identification of black holes must necessarily depend on the identification of a very specially behaving matter and radiation which surround them. A major problem in this subject of black hole astrophysics is to quantify the behaviour of matter and radiation close to the horizon. In this review, the subject of black hole accretion and outflow is systematically developed. It is shown that both the stationary as well as the non-stationary properties of the observed spectra could be generally understood by these solutions. It is suggested that the solutions of radiative hydrodynamic equations may produce clear spectral signatures of black holes. Other circumstantial evidences of black holes, both in the galactic centers as well as in binary systems, are also presented.
Juan Crisostomo; Ricardo Troncoso; Jorge Zanelli
2000-09-22
Gravitation theories selected by requiring that they have a unique anti-de Sitter vacuum with a fixed cosmological constant are studied. For a given dimension d, the Lagrangians under consideration are labeled by an integer k=1,2,...,[(d-1)/2]. Black holes for each d and k are found and are used to rank these theories. A minimum possible size for a localized electrically charged source is predicted in the whole set of theories, except General Relativity. It is found that the thermodynamic behavior falls into two classes: If d-2k=1, these solutions resemble the three dimensional black hole, otherwise, their behavior is similar to the Schwarzschild-AdS_4 geometry.
Webber, Bryan R
be presented and the effects of some of the uncertainties can be investigated. 3.1. Hawking Spectrum With the above assumptions, the spectrum of particles emitted during black hole decay takes the form dN dE ? ?E2 (eE/TH ? 1) T n+6H (8) where as usual... the trapped surface area [6, 7]. T030 02 4 6 8 10 0 0.2 0.4 0.6 0.8 1 1.2 n=0 n=1 n=2 n=6 E rS ?ˆ (0 ) ab s/ pi r2 S Figure 4: Grey-body factors for scalar emission on the brane from a (4 + n)D black hole. 0 2 4 6 8 10 0 0.2 0.4 0.6 0.8 1 1.2 n=0 n=1 n=2 n=6 E...
Mytko, Christine
2014-03-31
A group of seventh graders from Black Pine Circle school in Berkeley had the opportunity to experience the Advanced Light Source (ALS) as "users" via a collaborative field trip and proposal project. The project culminated with a field trip to the ALS for all seventh graders, which included a visit to the ALS data visualization room, a diffraction demonstration, a beamline tour, and informative sessions about x-rays and tomography presented by ALS scientists.
Mytko, Christine
2014-09-15
A group of seventh graders from Black Pine Circle school in Berkeley had the opportunity to experience the Advanced Light Source (ALS) as "users" via a collaborative field trip and proposal project. The project culminated with a field trip to the ALS for all seventh graders, which included a visit to the ALS data visualization room, a diffraction demonstration, a beamline tour, and informative sessions about x-rays and tomography presented by ALS scientists.
Laura Ferrarese
2002-03-04
The purpose of this contribution is to review the current status of black hole demographics in light of recent advances in the study of high redshift QSOs (section 2), local AGNs (section 3) and local quiescent galaxies (section 4). I will then outline the prospects for future progress (section 5), and discuss what I believe will be the challenges for the years to come [ABRIDGED].
Black holes in general relativity
Visser, Matt
2009-01-01
What is going on (as of August 2008) at the interface between theoretical general relativity, string-inspired models, and observational astrophysics? Quite a lot. In this mini-survey I will make a personal choice and focus on four specific questions: Do black holes "exist"? (For selected values of the word "exist".) Is black hole formation and evaporation unitary? Can one mimic a black hole to arbitrary accuracy? Can one detect the presence of a horizon using local physics?
Quantum Mechanics and Black Holes
Jose N. Pecina-Cruz
2005-11-27
This paper discusses the existence of black holes from the foundations of quantum mechanics. It is found that quantum mechanics rule out a possible gravitational collapse.
Why Blue-Collar Blacks Help Less
Smith, Sandra Susan; Young, Kara Alexis
2013-01-01
Exclude Black Men from Blue-Collar Jobs. Berkeley, CA:How Black and Latino Blue Collar Workers Make Decisionsof Sample Respondents Blue-Collar Latinos Blue-Collar Black
Dermoscopy of black-spot poison ivy
Rader, Ryan K; Mu, Ruipu; Shi, Honglan; Stoecker, William V; Hinton, Kristen A
2012-01-01
CT, Bean AS. Black-spot poison ivy: A rare phenomenon. J AmJG, Lucky AW. Black spot poison ivy: A report of 5 cases andis unique for black-spot poison ivy. The UFLC-MS/MS urushiol
Green, Black, Lean Six Sigma and Master Black Belt Certifications
Grissino-Mayer, Henri D.
Green, Black, Lean Six Sigma and Master Black Belt Certifications Green BeLt CertifiCation Candidates may choose from three Green Belts offered: 1) Lean (one week of coursework) 2) Lean Six Sigma (two weeks of coursework) 3) Six Sigma (two weeks of coursework) Green Belt certification is a two
Roberto Casadio; Andrea Giugno; Octavian Micu; Alessio Orlandi
2015-11-04
We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. An attractive self-interaction is needed for bound states to form, so that (approximately) one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The HWF is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a discrete ground state of energy $m$ (the bosons forming the black hole), and a continuous spectrum with energy $\\omega > m$ (representing the Hawking radiation and modelled with a Planckian distribution at the expected Hawking temperature). The $N$-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy $M = N m$ and a Planckian distribution for $E > M$ at the same Hawking temperature. The partition function is then found to yield the usual area law for the entropy, with a logarithmic correction related with the Hawking component. The backreaction of modes with $\\omega > m$ is also shown to reduce the Hawking flux and the evaporation properly stops for vanishing mass.
Holographic Black Hole Chemistry
Andreas Karch; Brandon Robinson
2015-11-02
Thermodynamic quantities associated with black holes in Anti-de Sitter space obey an interesting identity when the cosmological constant is included as one of the dynamical variables, the generalized Smarr relation. We show that this relation can easily be understood from the point of view of the dual holographic field theory. It amounts to the simple statement that the extensive thermodynamic quantities of a large $N$ gauge theory only depend on the number of colors, $N$, via an overall factor of $N^2$.
You Cannot Press Out the Black Hole
Daisuke Ida; Takahiro Okamoto
2012-01-03
It is shown that a ball-shaped black hole region homeomorphic with D**n cannot be pressed out, along whichever axis penetrating the black hole region, into a black ring with a doughnut-shaped black hole region homeomorphic with S**1 x D**(n-1). A more general prohibition law for the change of the topology of black holes, including a version of no-bifurcation theorems for black holes, is given.
Black Stars and Gamma Ray Bursts
Tanmay Vachaspati
2007-06-08
Stars that are collapsing toward forming a black hole but are frozen near the Schwarzschild horizon are termed ``black stars''. Collisions of black stars, in contrast to black hole collisions, may be sources of gamma ray bursts, whose basic parameters are estimated quite simply and are found to be consistent with observed gamma ray bursts. Black star gamma ray bursts should be preceded by gravitational wave emission similar to that from the coalescence of black holes.
Xu, Tengfang
2014-01-01
black liquor evaporation Lime kiln modifications Extended black liquor evaporation Lime kiln modifications Teriary effluents ClO2 filtrate heating Lime kiln oxygen enrichement
R. B. Mann
1997-05-06
I demonstrate that, under certain circumstances, regions of negative energy density can undergo gravitational collapse into a black hole. The resultant exterior black hole spacetimes necessarily have negative mass and non-trivial topology. A full theory of quantum gravity, in which topology-changing processes take place, could give rise to such spacetimes.
Industrial Heat Pumps for Steam and Fuel Savings: A BestPractices...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Process water heating Mechanical Compression, Closed cycle Wood Products Pulp manufacturing Concentration of black liquor Mechanical Vapor Compression, Open cycle...
Strings, higher curvature corrections, and black holes
Thomas Mohaupt
2005-12-05
We review old and recent results on subleading contributions to black hole entropy in string theory.
Physics: the big black box Mirror conjecture
Cavalieri, Renzo
Physics: the big black box Math Mirror conjecture A look into the mirror (I) an overview of Mirror Symmetry #12;Physics: the big black box Math Mirror conjecture Outline 1 Physics: the big black box 2 Math Symmetry #12;Physics: the big black box Math Mirror conjecture A slogan Mirror Symmetry is a correspondence
Black hole horizons Eric Gourgoulhon
Gourgoulhon, Eric
on a black hole: up to 42% of the mass-energy mc2 of accreted matter ! NB: thermonuclear reactions release: a very deep gravitational potential well Release of potential gravitational energy by accretion
Thermodynamics of regular black hole
Yun Soo Myung; Yong-Wan Kim; Young-Jai Park
2008-09-21
We investigate thermodynamics for a magnetically charged regular black hole (MCRBH), which comes from the action of general relativity and nonlinear electromagnetics, comparing with the Reissner-Norstr\\"om (RN) black hole in both four and two dimensions after dimensional reduction. We find that there is no thermodynamic difference between the regular and RN black holes for a fixed charge $Q$ in both dimensions. This means that the condition for either singularity or regularity at the origin of coordinate does not affect the thermodynamics of black hole. Furthermore, we describe the near-horizon AdS$_2$ thermodynamics of the MCRBH with the connection of the Jackiw-Teitelboim theory. We also identify the near-horizon entropy as the statistical entropy by using the AdS$_2$/CFT$_1$ correspondence.
Black Holes and Nuclear Dynamics
David Merritt
2006-02-17
Supermassive black holes inhabit galactic nuclei, and their presence influences in crucial ways the evolution of the stellar distribution. The low-density cores observed in bright galaxies are probably a result of black hole infall, while steep density cusps like those at the Galactic center are a result of energy exchange between stars moving in the gravitational field of the single black hole. Loss-cone dynamics are substantially more complex in galactic nuclei than in collisionally-relaxed systems like globular clusters due to the wider variety of possible geometries and orbital populations. The rate of star-black hole interactions has begun to be constrained through observations of energetic events associated with stellar tidal disruptions.
Black Boundary Lines: Race, Class and Gender among Black Undergraduate Students
Morales, Erica
2012-01-01
C. 1994. Behind the Mule: Race and Class in African AmericanHarlemworld: Doing Race and Class in Contemporary BlackBlue-Chip Black: Race, Class and Status in the New Black
A. Brotas
2006-09-01
The coordinate system $(\\bar{x},\\bar{t})$ defined by $r = 2m + K\\bar{x}- c K \\bar{t}$ and $t=\\bar{x}/cK - 1 /cK \\int_{r_a}^r (1- 2m/r + K^2)^{1/2} (1 - 2m/r)^{-1}dr$ allow us to write the Schwarzschild metric in the form: \\[ds^2=c^2 d\\bar{t}^2 + (W^2/K^2 - 2W/K) d\\bar{x}^2 + 2c (1 + W/K) d\\bar{x}d\\bar{t} - r^2 (d\\theta^2 + cos^2\\theta d\\phi^2)\\] with $W=(1 - 2m/r + K^2)^{1/2}$, in which the coefficients' pathologies are moved to $r_K = 2m/(1+K^2)$. This new coordinate system is used to study the entrance into a black hole of a rigid line (a line in which the shock waves propagate with velocity c).
Black hole mimickers: Regular versus singular behavior
Lemos, Jose P. S.; Zaslavskii, Oleg B.
2008-07-15
Black hole mimickers are possible alternatives to black holes; they would look observationally almost like black holes but would have no horizon. The properties in the near-horizon region where gravity is strong can be quite different for both types of objects, but at infinity it could be difficult to discern black holes from their mimickers. To disentangle this possible confusion, we examine the near-horizon properties, and their connection with far away asymptotic properties, of some candidates to black mimickers. We study spherically symmetric uncharged or charged but nonextremal objects, as well as spherically symmetric charged extremal objects. Within the uncharged or charged but nonextremal black hole mimickers, we study nonextremal {epsilon}-wormholes on the threshold of the formation of an event horizon, of which a subclass are called black foils, and gravastars. Within the charged extremal black hole mimickers we study extremal {epsilon}-wormholes on the threshold of the formation of an event horizon, quasi-black holes, and wormholes on the basis of quasi-black holes from Bonnor stars. We elucidate whether or not the objects belonging to these two classes remain regular in the near-horizon limit. The requirement of full regularity, i.e., finite curvature and absence of naked behavior, up to an arbitrary neighborhood of the gravitational radius of the object enables one to rule out potential mimickers in most of the cases. A list ranking the best black hole mimickers up to the worst, both nonextremal and extremal, is as follows: wormholes on the basis of extremal black holes or on the basis of quasi-black holes, quasi-black holes, wormholes on the basis of nonextremal black holes (black foils), and gravastars. Since in observational astrophysics it is difficult to find extremal configurations (the best mimickers in the ranking), whereas nonextremal configurations are really bad mimickers, the task of distinguishing black holes from their mimickers seems to be less difficult than one could think of it.
International black tea market integration and price discovery
Dharmasena, Kalu Arachchillage Senarath Dhananjaya Bandara
2004-09-30
In this thesis we study three basic issues related to international black tea markets: Are black tea markets integrated? Where is the price of black tea discovered? Are there leaders and followers in black tea markets? We ...
Energy on black hole spacetimes
Alejandro Corichi
2012-07-18
We consider the issue of defining energy for test particles on a background black hole spacetime. We revisit the different notions of energy as defined by different observers. The existence of a time-like isometry allows for the notion of a total conserved energy to be well defined, and subsequently the notion of a gravitational potential energy is also meaningful. We then consider the situation in which the test particle is adsorbed by the black hole, and analyze the energetics in detail. In particular, we show that the notion of horizon energy es defined by the isolated horizons formalism provides a satisfactory notion of energy compatible with the particle's conserved energy. As another example, we comment a recent proposal to define energy of the black hole as seen by an observer at rest. This account is intended to be pedagogical and is aimed at the level of and as a complement to the standard textbooks on the subject.
J. Sadeghi; Kh. Jafarzade
2015-06-23
As we know, the cosmological constant in different theories of gravity acts as a thermodynamics variable. The cosmological constant exists in different actions of gravity and also appears in the solution of such theories. These lead to use the black hole as a heat engines. Also, there are two values for the cosmological constant as positive and negative values. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. In this paper, we are going to define heat engines for two different black holes as Dyonic BH and Kerr BH. And also, we calculate maximum efficiency for two black holes.
Charged rotating dilaton black strings
Dehghani, M.H.; Farhangkhah, N.
2005-02-15
In this paper we, first, present a class of charged rotating solutions in four-dimensional Einstein-Maxwell-dilaton gravity with zero and Liouville-type potentials. We find that these solutions can present a black hole/string with two regular horizons, an extreme black hole or a naked singularity provided the parameters of the solutions are chosen suitable. We also compute the conserved and thermodynamic quantities, and show that they satisfy the first law of thermodynamics. Second, we obtain the (n+1)-dimensional rotating solutions in Einstein-dilaton gravity with Liouville-type potential. We find that these solutions can present black branes, naked singularities or spacetimes with cosmological horizon if one chooses the parameters of the solutions correctly. Again, we find that the thermodynamic quantities of these solutions satisfy the first law of thermodynamics.
Quantum Criticality and Black Holes
Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States
2009-09-01
I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.
Black Holes and Galaxy Dynamics
David Merritt
1999-06-02
The consequences of nuclear black holes for the structure and dynamics of stellar spheroids are reviewed. Slow growth of a black hole in a pre-existing core produces a steep power-law density profile similar to the cusps seen in faint elliptical galaxies. The weaker cusps in bright ellipticals may result from ejection of stars by a coalescing black-hole binary; there is marginal kinematical evidence for such a process having occurred in M87. Stellar orbits in a triaxial nucleus are mostly regular at radii where the gravitational force is dominated by the black hole; however the orbital shapes are not conducive to reinforcing the triaxial figure, hence nuclei are likely to be approximately axisymmetric. In triaxial potentials, a ``zone of chaos'' extends outward to a radius where the enclosed stellar mass is roughly 100 times the mass of the black hole; in this chaotic zone, no regular, box-like orbits exist. At larger radii, the phase space in triaxial potentials is complex, consisting of stochastic orbits as well as regular orbits associated with stable resonances. Figure rotation tends to increase the degree of stochasticity. Both test-particle integrations and N-body simulations suggest that a triaxial galaxy responds globally to the presence of a central mass concentration by evolving toward more axisymmetric shapes; the evolution occurs rapidly when the mass of the central object exceeds roughly 2% of the mass in stars. The lack of significant triaxiality in most early-type galaxies may be a consequence of orbital evolution induced by nuclear black holes.
Radiation transport around Kerr black holes
Schnittman, Jeremy David
2005-01-01
This Thesis describes the basic framework of a relativistic ray-tracing code for analyzing accretion processes around Kerr black holes. We begin in Chapter 1 with a brief historical summary of the major advances in black ...
Does phantom energy produce black hole?
F. Rahaman; A. Ghosh; M. Kalam
2006-12-23
We have found an exact solution of spherically symmetrical Einstein equations describing a black hole with a special type phantom energy source. It is surprising to note that our solution is analogous to Reissner-Nordstr\\"{o}m black hole.
Introduction to Black Hole Evaporation
Pierre-Henry Lambert
2014-01-16
These lecture notes are an elementary and pedagogical introduction to the black hole evaporation, based on a lecture given by the author at the Ninth Modave Summer School in Mathematical Physics and are intended for PhD students. First, quantum field theory in curved spacetime is studied and tools needed for the remaining of the course are introduced. Then, quantum field theory in Rindler spacetime in 1+1 dimensions and in the spacetime of a spherically collapsing star are considered, leading to Unruh and Hawking effects, respectively. Finally, some consequences such as thermodynamics of black holes and information loss paradox are discussed.
4d neutral dilatonic black holes and (4+p) dimensional nondilatonic black p-branes
J. R. Morris
2000-01-11
It is shown that, in contrast to the case of extreme 4d dilatonic black holes, 4d neutral dilatonic black holes with horizon singularities can not be interpreted as nonsingular nondilatonic black p-branes in (4+p) dimensions, regardless of the number of extra dimensions p. That is, extra dimensions do not remove naked singularities of 4d neutral dilatonic black holes.
Classical and thermodynamic stability of black holes
Ricardo Monteiro
2010-06-28
We consider the stability of black holes within both classical general relativity and the semiclassical thermodynamic description. In particular, we study linearised perturbations and their contribution to the gravitational partition function, addressing technical issues for charged (Reissner-Nordstrom) and rotating (Kerr-AdS) black holes. Exploring the connection between classical and thermodynamic stability, we find classical instabilities of Myers-Perry black holes and bifurcations to new black hole families.
Will black holes eventually engulf the universe?
Prado Martin-Moruno; Jose A. Jimenez Madrid; Pedro F. Gonzalez-Diaz
2006-03-28
The Babichev-Dokuchaev-Eroshenko model for the accretion of dark energy onto black holes has been extended to deal with black holes with non-static metrics. The possibility that for an asymptotic observer a black hole with large mass will rapidly increase and eventually engulf the Universe at a finite time in the future has been studied by using reasonable values for astronomical parameters. It is concluded that such a phenomenon is forbidden for all black holes in quintessential cosmological models.
Hawking Emission and Black Hole Thermodynamics
Don N. Page
2006-12-18
A brief review of Hawking radiation and black hole thermodynamics is given, based largely upon hep-th/0409024.
Scattering by regular black holes: Planar massless scalar waves impinging upon a Bardeen black hole
Macedo, Caio F B; Crispino, Luís C B
2015-01-01
Singularities are common features of general relativity black holes. However, within general relativity, one can construct black holes that present no singularities. These regular black hole solutions can be achieved by, for instance, relaxing one of the energy conditions on the stress energy tensor sourcing the black hole. Some regular black hole solutions were found in the context of non-linear electrodynamics, the Bardeen black hole being the first one proposed. In this paper, we consider a planar massless scalar wave scattered by a Bardeen black hole. We compare the scattering cross section computed using a partial-wave description with the classical geodesic scattering of a stream of null geodesics, as well as with the semi-classical glory approximation. We obtain that, for some values of the corresponding black hole charge, the scattering cross section of a Bardeen black hole has a similar interference pattern of a Reissner-Nordstr\\"om black hole.
Scattering by regular black holes: Planar massless scalar waves impinging upon a Bardeen black hole
Caio F. B. Macedo; Ednilton S. de Oliveira; Luís C. B. Crispino
2015-06-26
Singularities are common features of general relativity black holes. However, within general relativity, one can construct black holes that present no singularities. These regular black hole solutions can be achieved by, for instance, relaxing one of the energy conditions on the stress energy tensor sourcing the black hole. Some regular black hole solutions were found in the context of non-linear electrodynamics, the Bardeen black hole being the first one proposed. In this paper, we consider a planar massless scalar wave scattered by a Bardeen black hole. We compare the scattering cross section computed using a partial-wave description with the classical geodesic scattering of a stream of null geodesics, as well as with the semi-classical glory approximation. We obtain that, for some values of the corresponding black hole charge, the scattering cross section of a Bardeen black hole has a similar interference pattern of a Reissner-Nordstr\\"om black hole.
New approaches to black holes Eric Gourgoulhon
Gourgoulhon, Eric
References Eric Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 2 / 36 Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 3 / 36 #12;Local (2006)] Eric Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 4
Fenimore, Edward E.
2014-10-06
Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.
Extremal Higher Spin Black Holes
Máximo Bañados; Alejandra Castro; Alberto Faraggi; Juan I. Jottar
2015-11-30
The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require nor implies the existence of supersymmetry, we exemplify its consequences in the context of sl(3|2) + sl(3|2) Chern-Simons theory. Remarkably, while as usual not all extremal solutions preserve supersymmetries, we find that the higher spin setup allows for non-extremal supersymmetric black hole solutions as well. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2) + sl(3|2) Chern-Simons theory and two-dimensional CFTs with W_{(3|2)} symmetry, the simplest higher spin extension of the N=2 super-Virasoro algebra. In particular, we compute W_{(3|2)} BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N=2 two-dimensional CFTs with extended symmetry algebras.
Shaghoulian, Edgar
2015-01-01
We extend a recently derived higher-dimensional Cardy formula to include angular momenta, which we use to obtain the Bekensten-Hawking entropy of AdS black branes, compactified rotating branes, and large Schwarzschild/Kerr black holes. This is the natural generalization of Strominger's microscopic derivation of the BTZ black hole entropy to higher dimensions. We propose an extension to include $U(1)$ charge, which agrees with the Bekenstein-Hawking entropy of large Reissner-Nordstrom/Kerr-Newman black holes at high temperature. We extend the results to arbitrary hyperscaling violation exponent (this captures the case of black D$p$-branes as a subclass) and reproduce logarithmic corrections.
Black Hole Thermodynamics and Electromagnetism
Burra G. Sidharth
2005-07-15
We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.
Quantum chaos inside Black Holes
Addazi, Andrea
2015-01-01
We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensamble of horizonless naked singularities (eventually smoothed at the Planck scale). We call this new items {\\it frizzyballs}, which can be rigorously defined by euclidean path integral approach. This has interesting implications regarding information paradoxes. We demonstrate that infalling information will chaotically propagate inside this system before going to the full quantum gravity regime (Planck scale).
Quantum chaos inside Black Holes
Andrea Addazi
2015-08-30
We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensamble of horizonless naked singularities (eventually smoothed at the Planck scale). We call this new items {\\it frizzyballs}, which can be rigorously defined by euclidean path integral approach. This has interesting implications regarding information paradoxes. We demonstrate that infalling information will chaotically propagate inside this system before going to the full quantum gravity regime (Planck scale).
Erik Curiel
2014-11-09
In the early 1970s it is was realized that there is a striking formal analogy between the Laws of black-hole mechanics and the Laws of classical thermodynamics. Before the discovery of Hawking radiation, however, it was generally thought that the analogy was only formal, and did not reflect a deep connection between gravitational and thermodynamical phenomena. It is still commonly held that the surface gravity of a stationary black hole can be construed as a true physical temperature and its area as a true entropy only when quantum effects are taken into account; in the context of classical general relativity alone, one cannot cogently construe them so. Does the use of quantum field theory in curved spacetime offer the only hope for taking the analogy seriously? I think the answer is `no'. To attempt to justify that answer, I shall begin by arguing that the standard argument to the contrary is not physically well founded, and in any event begs the question. Looking at the various ways that the ideas of "temperature" and "entropy" enter classical thermodynamics then will suggest arguments that, I claim, show the analogy between classical black-hole mechanics and classical thermodynamics should be taken more seriously, without the need to rely on or invoke quantum mechanics. In particular, I construct an analogue of a Carnot cycle in which a black hole "couples" with an ordinary thermodynamical system in such a way that its surface gravity plays the role of temperature and its area that of entropy. Thus, the connection between classical general relativity and classical thermodynamics on their own is already deep and physically significant, independent of quantum mechanics.
Relationship of Black Holes to Bulges
David Merritt; Laura Ferrarese
2001-07-08
Supermassive black holes appear to be uniquely associated with galactic bulges. The mean ratio of black hole mass to bulge mass was until recently very uncertain, with ground based, stellar kinematical data giving a value roughly an order of magnitude larger than other techniques. The discrepancy was resolved with the discovery of the M-sigma relation, which simultaneously established a tight corrrelation between black hole mass and bulge velocity dispersion, and confirmed that the stellar kinematical mass estimates were systematically too large due to failure to resolve the black hole's sphere of influence. There is now excellent agreement between the various techniques for estimating the mean black hole mass, including dynamical mass estimation in quiescent galaxies; reverberation mapping in active galaxies and quasars; and computation of the mean density of compact objects based on integrated quasar light. Implications of the M-sigma relation for the formation of black holes are discussed.
Boson shells harboring charged black holes
Kleihaus, Burkhard; Kunz, Jutta; Laemmerzahl, Claus; List, Meike
2010-11-15
We consider boson shells in scalar electrodynamics coupled to Einstein gravity. The interior of the shells can be empty space, or harbor a black hole or a naked singularity. We analyze the properties of these types of solutions and determine their domains of existence. We investigate the energy conditions and present mass formulae for the composite black hole-boson shell systems. We demonstrate that these types of solutions violate black hole uniqueness.
Thermodynamic fluctuation in black string flow
Meng Sun; Yong-Chang Huna
2015-06-14
It has long been noticed that Laudau-Lifshitz theory can be used to study the fluctuation of a system that contains a black hole. Since the black string can be constructed by extending n-dimensional black hole into one extra dimension. We study the fluctuation of black string flow with a Schwarzschlid-like metric in D=n+1 dimensional spacetime and a charged solution in D=5 dimensional spacetime and get the second moments of the fluctuation of the mass flux and charge flux.
Thermodynamic fluctuation in black string flow
Meng Sun; Yong-Chang Huang
2015-05-11
It has long been noticed that Laudau-Lifshitz theory can be used to study the fluctuation of a system that contains a black hole. Since the black string can be constructed by extending n-dimensional black hole into one extra dimension. We study the fluctuation of black string flow with a Schwarzschlid-like metric in D=n+1 dimensional spacetime and a charged solution in D=5 dimensional spacetime and get the second moments of the fluctuation of the mass flux and charge flux.
Black carbon contribution to global warming
Chylek, P.; Johnson, B.; Kou, L.; Wong, J.
1996-12-31
Before the onset of industrial revolution the only important source of black carbon in the atmosphere was biomass burning. Today, black carbon production is divided between the biomass and fossil fuel burning. Black carbon is a major agent responsible for absorption of solar radiation by atmospheric aerosols. Thus black carbon makes other aerosols less efficient in their role of reflecting solar radiation and cooling the earth-atmosphere system. Black carbon also contributes to the absorption of solar radiation by clouds and snow cover. The authors present the results of black carbon concentrations measurements in the atmosphere, in cloud water, in rain and snow melt water collected during the 1992--1996 time period over the southern Nova Scotia. Their results are put into the global and historical perspective by comparing them with the compilation of past measurements at diverse locations and with their measurements of black carbon concentrations in the Greenland and Antarctic ice cores. Black carbon contribution to the global warming is estimated, and compared to the carbon dioxide warming, using the radiative forcing caused by the black carbon at the top of the atmosphere.
Lower Dimensional Black Holes: Inside and Out
R. B. Mann
1995-01-27
I survey the physics of black holes in two and three spacetime dimensions, with special attention given to an understanding of their exterior and interior properties.
Black Holes: from Speculations to Observations
Thomas W. Baumgarte
2006-04-13
This paper provides a brief review of the history of our understanding and knowledge of black holes. Starting with early speculations on ``dark stars'' I discuss the Schwarzschild "black hole" solution to Einstein's field equations and the development of its interpretation from "physically meaningless" to describing the perhaps most exotic and yet "most perfect" macroscopic object in the universe. I describe different astrophysical black hole populations and discuss some of their observational evidence. Finally I close by speculating about future observations of black holes with the new generation of gravitational wave detectors.
Rotating Black Holes and Coriolis Effect
Wu, Xiaoning; Yuan, Pei-Hung; Cho, Chia-Jui
2015-01-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Rotating Black Holes and Coriolis Effect
Xiaoning Wu; Yi Yang; Pei-Hung Yuan; Chia-Jui Cho
2015-11-27
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
L.A. Rebellion: Creating a New Black Cinema
Sheppard, Samantha Noelle
2011-01-01
Creating a New Black Cinema Symposium Review by SamanthaCreating a New Black Cinema By the turn of the next century,in the development of Black cinema took place at UCLA in the
Queering Black Gay Historiography: Performance, (Mis) Identifications, and Possibilities
Fitzgerald, Thomas Howard
2013-01-01
In 1976 the black comedy Car Wash featured a black gay manthe a openly black sissy in the Car Wash as a character thatsaw the distribution of Car Wash with Antoino Fargas playing
Extraordinary vacuum black string solutions
Kim, Hyeong-Chan; Lee, Jungjai
2008-01-15
In addition to the boosted static solution there are two other classes of stationary stringlike solutions of the vacuum Einstein equation in (4+1) dimensions. Each class is characterized by three parameters of mass, tension, and momentum flow along the fifth coordinate. We analyze the metric properties of one of the two classes, which was previously assumed to be naked singular, and show that the solution spectrum contains black string and wormhole in addition to the known naked singularity as the momentum flow to mass ratio increases. Interestingly, there does not exist new zero momentum solution in these cases.
Effective theories and black hole production in warped compactificatio...
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An electromagnetic black hole made of metamaterials
Qiang Cheng; Tie Jun Cui; Wei Xiang Jiang; Ben Geng Cai
2010-04-30
Traditionally, a black hole is a region of space with huge gravitational field, which absorbs everything hitting it. In history, the black hole was first discussed by Laplace under the Newton mechanics, whose event horizon radius is the same as the Schwarzschild's solution of the Einstein's vacuum field equations. If all those objects having such an event horizon radius but different gravitational fields are called as black holes, then one can simulate certain properties of the black holes using electromagnetic fields and metamaterials due to the similar propagation behaviours of electromagnetic waves in curved space and in inhomogeneous metamaterials. In a recent theoretical work by Narimanov and Kildishev, an optical black hole has been proposed based on metamaterials, in which the theoretical analysis and numerical simulations showed that all electromagnetic waves hitting it are trapped and absorbed. Here we report the first experimental demonstration of such an electromagnetic black hole in the microwave frequencies. The proposed black hole is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields and the event horizon corresponding to the device boundary. It is shown that the absorption rate can reach 99% in the microwave frequencies. We expect that the electromagnetic black hole could be used as the thermal emitting source and to harvest the solar light.
Black holes cannot support conformal scalar hair
T. Zannias
1994-09-14
It is shown that the only static asymptotically flat non-extrema black hole solution of the Einstein-conformally invariant scalar field equations having the scalar field bounded on the horizon, is the Schwarzschild one. Thus black holes cannot be endowed with conformal scalar hair of finite length.
Quantum Entropy of Charged Rotating Black Holes
R. B. Mann
1996-07-10
I discuss a method for obtaining the one-loop quantum corrections to the tree-level entropy for a charged Kerr black hole. Divergences which appear can be removed by renormalization of couplings in the tree-level gravitational action in a manner similar to that for a static black hole.
Topological Black Holes in Quantum Gravity
J. Kowalski-Glikman; D. Nowak-Szczepaniak
2000-07-31
We derive the black hole solutions with horizons of non-trivial topology and investigate their properties in the framework of an approach to quantum gravity being an extension of Bohm's formulation of quantum mechanics. The solutions we found tend asymptotically (for large $r$) to topological black holes. We also analyze the thermodynamics of these space-times.
Primordial black holes and asteroid danger
Alexander Shatskiy
2008-02-21
Probability for a primordial black hole to invade the Kuiper belt was calculated. We showed that primordial black holes of certain masses can significantly change asteroids' orbits. These events may result in disasters, local for our solar system and global for the Earth (like the Tunguska meteorite). We also estimated how often such events occur.
Stability of AdS black strings
T. Delsate
2008-08-14
We review the recent developements in the stability problem and phase diagram for asymptotically locally $AdS$ black strings. First, we quickly review the case of locally flat black string before turning to the case of locally $AdS$ spacetimes.
Canonical structure of 2D black holes
Navarro-Salas, J; Talavera, C F
1994-01-01
We determine the canonical structure of two-dimensional black-hole solutions arising in $2D$ dilaton gravity. By choosing the Cauchy surface appropriately we find that the canonically conjugate variable to the black hole mass is given by the difference of local (Schwarzschild) time translations at right and left spatial infinities. This can be regarded as a generalization of Birkhoff's theorem.
Fractal Statistics and Quantum Black Hole Entropy
Wellington da Cruz
2000-11-18
Simple considerations about the fractal characteristic of the quantum-mechanical path give us the opportunity to derive the quantum black hole entropy in connection with the concept of fractal statistics. We show the geometrical origin of the numerical factor of four of the quantum black hole entropy expression and the statistics weight appears as a counting of the quanta of geometry.
Lake, Matthew J
2015-01-01
The discovery of a large number of supermassive black holes at redshifts $z> 6$, when the Universe was only nine hundred million years old, has raised the fundamental question of how such massive compact objects could form in a (cosmologically) short time interval. Each of the proposed standard scenarios for black hole formation, involving rapid accretion of seed black holes, or black hole mergers, faces severe theoretical difficulties in explaining the short time formation of supermassive objects. In the present Letter, we propose an alternative scenario for the formation of supermassive black holes in the early Universe in which energy transfer from superconducting cosmic strings, piercing small seed black holes, is the main physical process leading to rapid mass increase. The increase in mass of a primordial seed black hole pierced by two antipodal strings is estimated and it is shown that this increases linearly in time. Due to the high energy transfer rate from the cosmic strings, we find that supermassi...
Class Transitions in Black Holes
Sandip K. Chakrabarti
2005-01-14
A black hole spectrum is known to change from the hard state to the soft state when the energy spectral index $\\alpha$ ($F_E \\propto E^{-\\alpha}$) in, say, 2-20 keV range changes from $\\alpha \\sim 0.5$ to $\\sim 1.5$. However, this `classical' definition which characterizes black holes like Cyg X-1, becomes less useful for many objects such as GRS 1915+105 in which the spectral slope is seen to vary from one to the other in a matter of seconds and depending on whether or not winds form, the spectral slope also changes. The light curves and the colour-colour diagrams may look completely different on different days depending on the frequency and mode of switching from one spectral state to the other. Though RXTE observations have yielded wealth of information on such `variability classes' in GRS 1915+105, very rarely one has been able to observe how the object goes from one class to the other. In the present review, we discuss possible origins of the class transition and present several examples of such transitions. In this context, we use mostly the results of the Indian X-ray Astronomy Experiment (IXAE) which observed GRS 1915+105 more regularly.
Nonthermal correction to black hole spectroscopy
Wen-Yu Wen
2014-11-14
Area spectrum of black holes have been obtained via various methods such as quasinormal modes, adiabatic invariance and angular momentum. Among those methods, calculations were done by assuming black holes in thermal equilibrium. Nevertheless, black holes in the asymptotically flat space usually have negative specific heat and therefore tend to stay away from thermal equilibrium. Even for those black holes with positive specific heat, temperature may still not be well defined in the process of radiation, due to the back reaction of decreasing mass. Respect to these facts, it is very likely that Hawking radiation is nonthermal and the area spectrum is no longer equidistant. In this note, we would like to illustrate how the area spectrum of black holes is corrected by this nonthermal effect.
Fourier Analysis of the BTZ Black Hole
Ian M. Tolfree
2009-11-11
In this paper we extend our previous work regarding the role of the Fourier transformation in bulk to boundary mappings to include the BTZ black hole. We follow standard procedures for modifying Fourier Transformations to accommodate quotient spaces and arrive at a bulk to boundary mapping in a black hole background. We show that this mapping is consistent with known results and lends a new insight into the AdS/CFT duality. We find that the micro-states corresponding to the entropy of a bulk scalar field are the Fourier coefficients on the boundary, which transform under the principal series representation of $SL(2,R)$. Building upon this we present a toy model to analyze the implications of this for the origin of black hole entropy. We find that the black hole micro-states live on the boundary and correspond to the possible emission modes of the black hole
Evidence for the Black Hole Event Horizon
Ramesh Narayan
2003-10-23
Astronomers have discovered many candidate black holes in X-ray binaries and in the nuclei of galaxies. The candidate objects are too massive to be neutron stars, and for this reason they are considered to be black holes. While the evidence based on mass is certainly strong, there is no proof yet that any of the objects possesses the defining characteristic of a black hole, namely an event horizon. Type I X-ray bursts, which are the result of thermonuclear explosions when gas accretes onto the surface of a compact star, may provide important evidence in this regard. Type I bursts are commonly observed in accreting neutron stars, which have surfaces, but have never been seen in accreting black hole candidates. It is argued that the lack of bursts in black hole candidates is compelling evidence that these objects do not have surfaces. The objects must therefore possess event horizons.
How fast can a black hole rotate?
Herdeiro, Carlos A R
2015-01-01
Kerr black holes have their angular momentum, $J$, bounded by their mass, $M$: $Jc\\leqslant GM^2$. There are, however, known black hole solutions violating this Kerr bound. We propose a very simple universal bound on the rotation, rather than on the angular momentum, of four-dimensional, stationary and axisymmetric, asymptotically flat black holes, given in terms of an appropriately defined horizon linear velocity, $v_H$. The $v_H$ bound is simply that $v_H$ cannot exceed the velocity of light. We verify the $v_H$ bound for known black hole solutions, including some that violate the Kerr bound, and conjecture that only extremal Kerr black holes saturate the $v_H$ bound.
Morphology of PolyethyleneCarbon Black Composites G. BEAUCAGE,1
Beaucage, Gregory
-ray scattering (SAXS) study of a conductive grade of carbon black and carbon blackpolymer composites and a power-law scaling of polydispersity. One use of conductive blackpolyethylene composites is in circuit(methyl methacrylate); carbon black; filler; composite; conductivity; percolation INTRODUCTION The morphology
Testing black hole candidates with electromagnetic radiation
Bambi, Cosimo
2015-01-01
Astrophysical black hole candidates are thought to be the Kerr black holes of general relativity, but there is currently no direct observational evidence that the spacetime geometry around these objects is described by the Kerr solution. The study of the properties of the electromagnetic radiation emitted by gas or stars orbiting these objects can potentially test the Kerr black hole hypothesis. In this paper, I review the state of the art of this research field, describing the possible approaches to test the Kerr metric with current and future observational facilities and discussing current constraints.
Quasinormal Modes of Dirty Black Holes
P. T. Leung; Y. T. Liu; W. -M. Suen; C. Y. Tam; K. Young
1999-03-08
Quasinormal mode (QNM) gravitational radiation from black holes is expected to be observed in a few years. A perturbative formula is derived for the shifts in both the real and the imaginary part of the QNM frequencies away from those of an idealized isolated black hole. The formulation provides a tool for understanding how the astrophysical environment surrounding a black hole, e.g., a massive accretion disk, affects the QNM spectrum of gravitational waves. We show, in a simple model, that the perturbed QNM spectrum can have interesting features.
Black Hole Thermodynamics and Statistical Mechanics
Steven Carlip
2008-07-28
We have known for more than thirty years that black holes behave as thermodynamic systems, radiating as black bodies with characteristic temperatures and entropies. This behavior is not only interesting in its own right; it could also, through a statistical mechanical description, cast light on some of the deep problems of quantizing gravity. In these lectures, I review what we currently know about black hole thermodynamics and statistical mechanics, suggest a rather speculative "universal" characterization of the underlying states, and describe some key open questions.
Some remarks on black hole thermodynamics
R. Y. Chiao
2011-02-04
Two thermodynamic "paradoxes" of black hole physics are re-examined. The first is that there is a thermal instability involving two coupled blackbody cavities containing two black holes, and second is that a classical black hole can swallow up entropy in the form of ambient blackbody photons without increasing its mass. The resolution of the second paradox by Bekenstein and by Hawking is re-visited. The link between Hawking radiation and Wigner's superluminal tunneling time is discussed using two equivalent Feynman diagrams, and Feynman's re-interpretation principle.
Thermodynamics of Dyonic Lifshitz Black Holes
Tobias Zingg
2011-07-15
Black holes with asymptotic anisotropic scaling are conjectured to be gravity duals of condensed matter system close to quantum critical points with non-trivial dynamical exponent z at finite temperature. A holographic renormalization procedure is presented that allows thermodynamic potentials to be defined for objects with both electric and magnetic charge in such a way that standard thermodynamic relations hold. Black holes in asymptotic Lifshitz spacetimes can exhibit paramagnetic behavior at low temperature limit for certain values of the critical exponent z, whereas the behavior of AdS black holes is always diamagnetic.
Testing the Kerr black hole hypothesis
Cosimo Bambi
2011-10-13
It is thought that the final product of the gravitational collapse is a Kerr black hole and astronomers have discovered several good astrophysical candidates. While there is some indirect evidence suggesting that the latter have an event horizon, and therefore that they are black holes, a proof that the space-time around these objects is described by the Kerr geometry is still lacking. Recently, there has been an increasing interest in the possibility of testing the Kerr black hole hypothesis with present and future experiments. In this paper, I briefly review the state of the art of the field, focussing on some recent results and work in progress.
Scalar Perturbations of Charged Dilaton Black Holes
Sharmanthie Fernando; Keith Arnold
2015-08-01
We have studied the scalar perturbation of static charged dilaton black holes in 3+1 dimensions. The black hole considered here is a solution to the low-energy string theory in 3+1 dimensions. The quasinormal modes for the scalar perturbations are calculated using the third order WKB method. The dilaton coupling constant has a considerable effect on the values of quasi normal modes. It is also observed that there is a linear relation between the quasi normal modes and the temperature for large black holes.
Energy density bounds for black strings
Shinya Tomizawa
2005-06-07
The conserved charge called Y-ADM mass density associated with asymptotically translational Killing-Yano tensor gives us an appropriate physical meaning about the energy density of $p$ brane spacetimes or black strings. We investigated the positivity of energy density in black string spacetimes, using the spinorial technique introduced by Witten. Recently, the positivity of Y-ADM mass density in p brane spacetimes was discussed. In this paper, we will extend this discussion to the transversely asymptotically flat black string spacetimes containing an apparent horizon. We will give the sufficient conditions for the Y-ADM mass density to become positive in such spacetimes.
Thermodynamics and evaporation of the noncommutative black hole
Yun Soo Myung; Yong-Wan Kim; Young-Jai Park
2007-01-21
We investigate the thermodynamics of the noncommutative black hole whose static picture is similar to that of the nonsingular black hole known as the de Sitter-Schwarzschild black hole. It turns out that the final remnant of extremal black hole is a thermodynamically stable object. We describe the evaporation process of this black hole by using the noncommutativity-corrected Vaidya metric. It is found that there exists a close relationship between thermodynamic approach and evaporation process.
Energy of 4-Dimensional Black Hole, etc
Dmitriy Palatnik
2011-07-18
In this letter I suggest possible redefinition of mass density, not depending on speed of the mass element, which leads to a more simple stress-energy for an object. I calculate energy of black hole.
Horizon Operator Approach to Black Hole Quantization
G. 't Hooft
1994-02-21
The $S$-matrix Ansatz for the construction of a quantum theory of black holes is further exploited. We first note that treating the metric tensor $g_{\\m\
Topological Black Holes -- Outside Looking In
R. B. Mann
1997-09-15
I describe the general mathematical construction and physical picture of topological black holes, which are black holes whose event horizons are surfaces of non-trivial topology. The construction is carried out in an arbitrary number of dimensions, and includes all known special cases which have appeared before in the literature. I describe the basic features of massive charged topological black holes in $(3+1)$ dimensions, from both an exterior and interior point of view. To investigate their interiors, it is necessary to understand the radiative falloff behaviour of a given massless field at late times in the background of a topological black hole. I describe the results of a numerical investigation of such behaviour for a conformally coupled scalar field. Significant differences emerge between spherical and higher genus topologies.
Evidence for the Black Hole Event Horizon
Ramesh Narayan; Jeremy S. Heyl
2002-04-26
Roughly a dozen X-ray binaries are presently known in which the compact accreting primary stars are too massive to be neutron stars. These primaries are identified as black holes, though there is as yet no definite proof that any of the candidate black holes actually possesses an event horizon. We discuss how Type I X-ray bursts may be used to verify the presence of the event horizon in these objects. Type I bursts are caused by thermonuclear explosions when gas accretes onto a compact star. The bursts are commonly seen in many neutron star X-ray binaries, but they have never been seen in any black hole X-ray binary. Our model calculations indicate that black hole candidates ought to burst frequently if they have surfaces. Based on this, we argue that the lack of bursts constitutes strong evidence for the presence of event horizons in these objects.
CHARYBDIS: A Black hole event generator.
Harris, Chris M.; Richardson, P.; Webber, Bryan R.
CHARYBDIS is an event generator which simulates the production and decay of miniature black holes at hadronic colliders as might be possible in certain extra dimension models. It interfaces via the Les Houches accord to general purpose Monte...
Spacetime constraints on accreting black holes
Garofalo, David [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California 91109 (United States)
2009-06-15
We study the spin dependence of accretion onto rotating Kerr black holes using analytic techniques. In its linear regime, angular momentum transport in MHD turbulent accretion flow involves the generation of radial magnetic field connecting plasma in a differentially rotating flow. We take a first principles approach, highlighting the constraint that limits the generation and amplification of radial magnetic fields, stemming from the transfer of energy from mechanical to magnetic form. Because the energy transferred in magnetic form is ultimately constrained by gravitational potential energy or Killing energy, the spin dependence of the latter allows us to derive spin-dependent constraints on the success of the accreting plasma to expel its angular momentum. We find an inverse relationship between this ability and black hole spin. If this radial magnetic field generation forms the basis for angular momentum transfer in accretion flows, accretion rates involving Kerr black holes are expected to be lower as the black hole spin increases in the prograde sense.
Black Hills Energy- Solar Power Program
Broader source: Energy.gov [DOE]
All incentive payments are subject to the availability of funds and a pre-installation site inspection. Black Hills Energy has established participation caps for each tier. The status of funding ...
Classical and thermodynamic stability of black holes
Monteiro, Ricardo
2010-07-06
Perturbations of the asymptotic charges . . . . . . . . . . . . . . . . 169 IV Conclusion 171 9 Conclusion and outlook 173 A Spectral numerical method 177 2 CONTENTS Part I Introduction 3 Chapter 1 Black holes Black holes are arguably the most interesting... to Newto- nian dynamics in the Solar system, and the indirect detection of gravitational waves from binary pulsars [1]. A crucial distinction from Newtonian gravity is that the “action-at-a-distance” is substituted by a built-in causality structure...
Charged Cylindrical Black Holes in Conformal Gravity
Jackson Levi Said; Joseph Sultana; Kristian Zarb Adami
2013-01-04
Considering cylindrical topology we present the static solution for a charged black hole in conformal gravity. We show that unlike the general relativistic case there are two different solutions, both including a factor that when set to zero recovers the familiar static charged black string solution in Einstein's theory. This factor gives rise to a linear term in the potential that also features in the neutral case and may have significant ramifications for particle trajectories.
Black Holes and Biophysical (Mem)-branes
Jay Armas; Troels Harmark
2014-11-26
We argue that the effective theory describing the long-wavelength dynamics of black branes is the same effective theory that describes the dynamics of biophysical membranes. We improve the phase structure of higher-dimensional black rings by considering finite thickness corrections in this effective theory, showing a striking agreement between our analytical results and recent numerical constructions while simultaneously drawing a parallel between gravity and the effective theory of biophysical membranes.
Fractionated Branes and Black Hole Interiors
Emil J. Martinec
2015-05-20
Combining a variety of results in string theory and general relativity, a picture of the black hole interior is developed wherein spacetime caps off at an inner horizon, and the inter-horizon region is occupied by a Hagedorn gas of a very low tension state of fractionated branes. This picture leads to natural resolutions of a variety of puzzles concerning quantum black holes. Gravity Research Foundation 2015 Fourth Prize Award for Essays on Gravitation.
Nanoscopy Reveals Metallic Black Phosphorus
Abate, Yohannes; Zhen, Li; Cronin, Stephen B; Wang, Han; Babicheva, Viktoriia; Javani, Mohammad H; Stockman, Mark I
2015-01-01
Layered and two-dimensional (2D) materials such as graphene, boron nitride, transition metal dichalcogenides(TMDCs), and black phosphorus (BP) have intriguing fundamental physical properties and bear promise of numerous important applications in electronics and optics. Of them, BP is a novel 2D material that has been theoretically predicted to acquire plasmonic behavior for frequencies below ~0.4 eV when highly doped. The electronic properties of BP are unique due to an anisotropic structure, which could strongly influence collective electronic excitations. Advantages of BP as a material for nanoelectronics and nanooptics are due to the fact that, in contrast to metals, the free carrier density in it can be dynamically controlled by electrostatic gating, which has been demonstrated by its use in field-effect transistors. Despite all the interest that BP attracts, near-field and plasmonic properties of BP have not yet been investigated experimentally. Here we report the first observation of nanoscopic near-fie...
Rotating black hole thermodynamics with a particle probe
Gwak, Bogeun; Lee, Bum-Hoon
2011-10-15
The thermodynamics of Myers-Perry black holes in general dimensions are studied using a particle probe. When undergoing particle absorption, the changes of the entropy and irreducible mass are shown to be dependent on the particle radial momentum. The black hole thermodynamic behaviors are dependent on dimensionality for specific rotations. For a 4-dimensional Kerr black hole, its black hole properties are maintained for any particle absorption. 5-dimensional black holes can avoid a naked ring singularity by absorbing a particle in specific momenta ranges. Black holes over 6 dimensions become ultraspinning black holes through a specific form of particle absorption. The microscopical changes are interpreted in limited cases of Myers-Perry black holes using Kerr/CFT correspondence. We systematically describe the black hole properties changed by particle absorption in all dimensions.
Lumpy AdS$\\bf{_5\\times}$ S$\\bf{^5}$ Black Holes and Black Belts
Oscar J. C. Dias; Jorge E. Santos; Benson Way
2015-01-26
Sufficiently small Schwarzschild black holes in global AdS$_5\\times$S$^5$ are Gregory-Laflamme unstable. We construct new families of black hole solutions that bifurcate from the onset of this instability and break the full SO$(6)$ symmetry group of the S$^5$ down to SO$(5)$. These new "lumpy" solutions are labelled by the harmonics $\\ell$. We find evidence that the $\\ell = 1$ branch never dominates the microcanonical/canonical ensembles and connects through a topology-changing merger to a localised black hole solution with S$^8$ topology. We argue that these S$^8$ black holes should become the dominant phase in the microcanonical ensemble for small enough energies, and that the transition to Schwarzschild black holes is first order. Furthermore, we find two branches of solutions with $\\ell = 2$. We expect one of these branches to connect to a solution containing two localised black holes, while the other branch connects to a black hole solution with horizon topology $\\mathrm S^4\\times\\mathrm S^4$ which we call a "black belt".
Oxygen-Enriched Combustion; Industrial Technologies Program ...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Reheat, soaking pits, ladles Aluminum Melting Copper Smelting and melting Glass Melting Pulp and Paper Lime kilns, black liquor boilers Petroleum Process heaters, crackers Power...
Understanding the 2014 Manufacturing Energy and Carbon Footprints
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
examples of byproduct fuels include black liquor and wood byproducts in pulp and paper mills and still gas in petroleum refineries. As noted earlier in this document, a...
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Anaerobic digestion Anaerobic Digester Gas Boiler fuel * Wood and Wood Waste Pulp and paper mills produce Black Liquor Gasification Biomass Gas Fermentation Ethanol Figure 2-2....
Analysis of Energy-Efficiency Opportunities for the Pulp and Paper Industry in China
Kong, Lingbo
2014-01-01
Condensate return Optimize air system Real-time energy-management system Shoe press Anaerobic wastewater treatment Black liquor concentration Waste heat recovery
Xu, Tengfang
2014-01-01
screen out thick chips, boiler maintenance, steam trapSteam Production and Efficiency Boiler maintenance Improved of black liquor in recovery boiler High temperature video
Clean Energy Technologies: A Preliminary Inventory of the Potential for Electricity Generation
Bailey, Owen; Worrell, Ernst
2005-01-01
of biomass integrated-gasifier/gas turbine combined cyclefarms to large integrated gasifiers at petroleum refineries.BLGCC). The black liquor gasifier technology will produce a
Holographic superconductor in the exact hairy black hole
Yun Soo Myung; Chanyong Park
2011-09-13
We study the charged black hole of hyperbolic horizon with scalar hair (charged Martinez-Troncoso-Zanelli: CMTZ black hole) as a model of analytic hairy black hole for holographic superconductor. For this purpose, we investigate the second order phase transition between CMTZ and hyperbolic Reissner-Nordstr\\"om-AdS (HRNAdS) black holes. However, this transition unlikely occur. As an analytic treatment for holographic superconductor, we develop superconductor in the bulk and superfluidity on the boundary using the CMTZ black hole below the critical temperature. The presence of charge destroys the condensates around the zero temperature, which is in accord with the thermodynamic analysis of the CMTZ black hole.
Electrically charged black hole with scalar hair
Cristian Martinez; Ricardo Troncoso
2006-06-16
An electrically charged black hole solution with scalar hair in four dimensions is presented. The self-interacting scalar field is real and it is minimally coupled to gravity and electromagnetism. The event horizon is a surface of negative constant curvature and the asymptotic region is locally an AdS spacetime. The asymptotic fall-off of the fields is slower than the standard one. The scalar field is regular everywhere except at the origin, and is supported by the presence of electric charge which is bounded from above by the AdS radius. In turn, the presence of the real scalar field smooths the electromagnetic potential everywhere. Regardless the value of the electric charge, the black hole is massless and has a fixed temperature. The entropy follows the usual area law. It is shown that there is a nonvanishing probability for the decay of the hairy black hole into a charged black hole without scalar field. Furthermore, it is found that an extremal black hole without scalar field is likely to undergo a spontaneous dressing up with a nontrivial scalar field, provided the electric charge is below a critical value.
The Environmental Impact of Supermassive Black Holes
Abraham Loeb
2004-08-10
The supermassive black holes observed at the centers of almost all present-day galaxies, had a profound impact on their environment. I highlight the principle of self-regulation, by which supermassive black holes grow until they release sufficient energy to unbind the gas that feeds them from their host galaxy. This principle explains several observed facts, including the correlation between the mass of a central black hole and the depth of the gravitational potential well of its host galaxy, and the abundance and clustering properties of bright quasars in the redshift interval of z~2-6. At lower redshifts, quasars might have limited the maximum mass of galaxies through the suppression of cooling flows in X-ray clusters. The seeds of supermassive black holes were likely planted in dwarf galaxies at redshifts z>10, through the collapse of massive or supermassive stars. The minimum seed mass can be identified observationally through the detection of gravitational waves from black hole binaries by Advanced LIGO or LISA. Aside from shaping their host galaxies, quasar outflows filled the intergalactic medium with magnetic fields and heavy elements. Beyond the reach of these outflows, the brightest quasars at z>6 have ionized exceedingly large volumes of gas (tens of comoving Mpc) prior to global reionization, and must have suppressed the faint end of the galaxy luminosity function in these volumes before the same occurred through the rest of the universe.
Perturbative String Thermodynamics near Black Hole Horizons
Thomas G. Mertens; Henri Verschelde; Valentin I. Zakharov
2015-07-01
We provide further computations and ideas to the problem of near-Hagedorn string thermodynamics near (uncharged) black hole horizons, building upon our earlier work JHEP 1403 (2014) 086. The relevance of long strings to one-loop black hole thermodynamics is emphasized. We then provide an argument in favor of the absence of $\\alpha'$-corrections for the (quadratic) heterotic thermal scalar action in Rindler space. We also compute the large $k$ limit of the cigar orbifold partition functions (for both bosonic and type II superstrings) which allows a better comparison between the flat cones and the cigar cones. A discussion is made on the general McClain-Roth-O'Brien-Tan theorem and on the fact that different torus embeddings lead to different aspects of string thermodynamics. The black hole/string correspondence principle for the 2d black hole is discussed in terms of the thermal scalar. Finally, we present an argument to deal with arbitrary higher genus partition functions, suggesting the breakdown of string perturbation theory (in $g_s$) to compute thermodynamical quantities in black hole spacetimes.
Thermodynamics and Luminosities of Rainbow Black Holes
Benrong Mu; Peng Wang; Haitang Yang
2015-07-14
Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As a result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is \\textquotedblleft Gravity's rainbow", where the spacetime background felt by a test particle would depend on its energy. Focusing on the \\textquotedblleft Amelino-Camelia dispersion relation" which is $E^{2}=m^{2}+p^{2}\\left[ 1-\\eta\\left( E/m_{p}\\right) ^{n}\\right] $ with $n>0$, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of $\\eta$ and $n$ in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with $\\eta<0$ and $n\\geq2$. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of $\\eta$ and $n$.
Black Hole Spin in AGN and GBHCs
Christopher S. Reynolds; Laura W. Brenneman; David Garofalo
2004-10-05
We discuss constraints on black hole spin and spin-related astrophysics as derived from X-ray spectroscopy. After a brief discussion about the robustness with which X-ray spectroscopy can be used to probe strong gravity, we summarize how these techniques can constrain black hole spin. In particular, we highlight XMM-Newton studies of the Seyfert galaxy MCG-6-30-15 and the stellar-mass black hole GX339-4. The broad X-ray iron line profile, together with reasonable and general astrophysical assumptions, allow a non-rotating black hole to be rejected in both of these sources. If we make the stronger assertion of no emission from within the innermost stable circular orbit, the MCG-6-30-15 data constrain the dimensionless spin parameter to be a>0.93. Furthermore, these XMM-Newton data are already providing evidence for exotic spin-related astrophysics in the central regions of this object. We conclude with a discussion of the impact that Constellation-X will have on the study of strong gravity and black hole spin.
Investigating Dark Energy with Black Hole Binaries
Laura Mersini-Houghton; Adam Kelleher
2009-06-08
The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accretion of dark energy induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time scale during which the mass of black holes changes considerably is too long relative to the age of the universe, thus beyond detection possibilities. We propose to take advantage of the modified black hole masses for exploring the equation of state $w[z]$ of dark energy, by investigating the evolution of supermassive black hole binaries on a dark energy background. Deriving the signatures of dark energy accretion on the evolution of binaries, we find that dark energy imprints on the emitted gravitational radiation and on the changes in the orbital radius of the binary can be within detection limits for certain supermassive black hole binaries. In this talk I describe how binaries can provide a useful tool in obtaining complementary information on the nature of dark energy, based on the work done with A.Kelleher.
Rotating black lens solution in five dimensions
Chen Yu; Teo, Edward
2008-09-15
It has recently been shown that a stationary, asymptotically flat vacuum black hole in five space-time dimensions with two commuting axial symmetries must have an event horizon with either a spherical, ring or lens-space topology. In this paper, we study the third possibility, a so-called black lens with L(n,1) horizon topology. Using the inverse scattering method, we construct a black-lens solution with the simplest possible rod structure, and possessing a single asymptotic angular momentum. Its properties are then analyzed; in particular, it is shown that there must either be a conical singularity or a naked curvature singularity present in the space-time.
Neutrino Majorana Mass from Black Hole
Yosuke Uehara
2002-05-25
We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of higher-dimensional spacetime can result in the production of a black hole, which emits 2 neutrinos. If neutrinos are Majorana particles, this process is equivalent to the free propagation of a neutrino with the insertion of the black hole. From this fact, we derive the neutrino Majorana mass. The result is completely consistent with the recently observed evidence of neutrinoless double beta decay. And the obtained neutrino Majorana mass satisfies the constraint from the density of the neutrino dark matter, which affects the cosmic structure formation. Furthermore, we can explain the ultrahigh energy cosmic rays by the Z-burst scenario with it.
Numerical Analysis of Black Hole Evaporation
Tsvi Piran; Andrew Strominger
1993-04-28
Black hole formation/evaporation in two-dimensional dilaton gravity can be described, in the limit where the number $N$ of matter fields becomes large, by a set of second-order partial differential equations. In this paper we solve these equations numerically. It is shown that, contrary to some previous suggestions, black holes evaporate completely a finite time after formation. A boundary condition is required to evolve the system beyond the naked singularity at the evaporation endpoint. It is argued that this may be naturally chosen so as to restore the system to the vacuum. The analysis also applies to the low-energy scattering of $S$-wave fermions by four-dimensional extremal, magnetic, dilatonic black holes.
Black Hole Thermodynamics in Modified Gravity
Jonas R. Mureika; John W. Moffat; Mir Faizal
2015-03-03
We analyze the thermodynamics of a non-rotating and rotating black hole in a modified theory of gravity that includes scalar and vector modifications to general relativity, which results in a modified gravitational constant $G = G_N(1+\\alpha)$ and a new gravitational charge $Q = \\sqrt{\\alpha G_N}M$. The influence of the parameter $\\alpha$ alters the non-rotating black hole's lifetime, temperature and entropy profiles from the standard Schwarzschild case. The thermodynamics of a rotating black hole is analyzed and it is shown to possess stable, cold remnants. The thermodynamic properties of a vacuum solution regular at $r=0$ are investigated and the solution without a horizon called a "gray hole" is not expected to possess an information loss problem.
No Supermassive Black Hole in M33?
David Merritt; Laura Ferrarese; Charles L. Joseph
2001-07-20
We analyze optical long-slit spectroscopy of the nucleus of M33 obtained from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Rather than the steep rise expected within the radius of influence of a supermassive black hole, the velocity dispersion drops significantly within the inner parsec. Dynamical modelling yields an estimated upper limit of 3000 solar masses for the mass of a central compact object. This upper limit is however consistent within the uncertainties with the mass predicted by the M-sigma relation, which is between 2000 and 20,000 solar masses. We therefore can not conclude that the presence of a massive black hole in the nucleus of M33 would require a different formation mechanism from that of the black holes detected in galaxies with more luminous bulges.
Dynamics of galaxy cores and supermassive black holes
David Merritt
2006-05-02
Recent work on the dynamical evolution of galactic nuclei containing supermassive black holes is reviewed. Topics include galaxy structural properties; collisionless and collisional equilibria; loss-cone dynamics; and dynamics of binary and multiple supermassive black holes.
Black hole Meissner effect and Blandford-Znajek jets
Penna, Robert
Spinning black holes tend to expel magnetic fields. In this way they are similar to superconductors. It has been a persistent concern that this black hole “Meissner effect” could quench jet power at high spins. This would ...
CHARYBDIS: A Black Hole Event Generator
C. M. Harris; P. Richardson; B. R. Webber
2003-07-29
CHARYBDIS is an event generator which simulates the production and decay of miniature black holes at hadronic colliders as might be possible in certain extra dimension models. It interfaces via the Les Houches accord to general purpose Monte Carlo programs like HERWIG and PYTHIA which then perform the parton evolution and hadronization. The event generator includes the extra-dimensional `grey-body' effects as well as the change in the temperature of the black hole as the decay progresses. Various options for modelling the Planck-scale terminal decay are provided.
Virtual Black Holes in Hyperbolic Metamaterials
Igor I. Smolyaninov
2011-01-24
Optical space in electromagnetic metamaterials may be engineered to emulate various exotic space-time geometries. However, these metamaterial models are limited in many respects. It is believed that real physical space-time strongly fluctuates on the Planck scale. These fluctuations are usually described as virtual black holes. Static metamaterial models introduced so far do not exhibit similar behavior. Here we demonstrate that thermal fluctuations of optical space in hyperbolic metamaterials lead to creation of virtual electromagnetic black holes. This effect is very large if the dielectric component of the metamaterial exhibits critical opalescence.
Vacuum polarization for lukewarm black holes
Elizabeth Winstanley; Phil M. Young
2007-12-20
We compute the renormalized expectation value of the square of a quantum scalar field on a Reissner-Nordstrom-de Sitter black hole in which the temperatures of the event and cosmological horizons are equal (`lukewarm' black hole). Our numerical calculations for a thermal state at the same temperature as the two horizons indicate that this renormalized expectation value is regular on both the event and cosmological horizons. We are able to show analytically, using an approximation for the field modes near the horizons, that this is indeed the case.
Thermal Gravitational Waves from Primordial Black Holes
C. Sivaram; Kenath Arun
2010-05-19
Thermal gravitational waves can be generated in various sources such as, in the cores of stars, white dwarfs and neutron stars due to the fermion collisions in the dense degenerate Fermi gas. Such high frequency thermal gravitational waves can also be produced during the collisions in a gamma ray burst or during the final stages of the evaporation of primordial black holes. Here we estimate the thermal gravitational waves from primordial black holes and estimate the integrated energy of the gravitational wave emission over the entire volume of the universe and over Hubble time. We also estimate the gravitational wave flux from gamma ray bursts and jets.
Thermal stability of radiant black holes
Parthasarathi Majumdar
2006-04-06
Beginning with a brief sketch of the derivation of Hawking's theorem of horizon area increase, based on the Raychaudhuri equation, we go on to discuss the issue as to whether generic black holes, undergoing Hawking radiation, can ever remain in stable thermal equilibrium with that radiation. We derive a universal criterion for such a stability, which relates the black hole mass and microcanonical entropy, both of which are well-defined within the context of the Isolated Horizon, and in principle calculable within Loop Quantum Gravity. The criterion is argued to hold even when thermal fluctuations of electric charge are considered, within a {\\it grand} canonical ensemble.
Magnetized black hole as a gravitational lens
R. A. Konoplya
2006-11-19
We use the Ernst-Schwarzschild solution for a black hole immersed in a uniform magnetic field to estimate corrections to the bending angle and time delay due-to presence of weak magnetic fields in galaxies and between galaxies, and also due-to influence of strong magnetic field near supermassive black holes. The magnetic field creates a kind of confinement in space, that leads to increasing of the bending angle and time delay for a ray of light propagating in the equatorial plane.
Entropy and Area of Black Holes in Loop Quantum Gravity
I. B. Khriplovich
2002-03-31
Simple arguments related to the entropy of black holes strongly constrain the spectrum of the area operator for a Schwarzschild black hole in loop quantum gravity. In particular, this spectrum is fixed completely by the assumption that the black hole entropy is maximum. Within the approach discussed, one arrives in loop quantum gravity at a quantization rule with integer quantum numbers $n$ for the entropy and area of a black hole.
UofT Wireless Network BlackBerry 6 Setup
UofT Wireless Network BlackBerry 6 Setup Note:theseinstructionsweretestedonaBlackBerryBold9700,OS6-4357,help.desk@utoronto.ca). UofT Wireless Network BlackBerry 10 Setup Note: these instructions were tested on a BlackBerry Q10. 1. Before you can use the UofT wireless network, you must verify your UTORid (you
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ASTROPHYSICS; BLACK HOLES; COMPARATIVE EVALUATIONS; CORRELATIONS; COSMOLOGY; GALAXIES; GALAXY NUCLEI; NONLUMINOUS MATTER; OSCILLATIONS; QUASARS; VELOCITY Word Cloud More Like This...
Location and Geology Fig 1. The Macasty black shale
to the chondritic uniform reservoir (CHUR; black line) and the depleted mantle (purple line). The parameters of CHUR by calcite. Fig. 5. Pyritized fracture Fig. 6. Massive black shale Fig. 7. Graptolite in black shale Fig. 8 shale, - Measure the concentrations of major, minor and trace elements including organic carbon
Emission of scalar particles from cylindrical black holes
H. Gohar; K. Saifullah
2011-09-27
We study quantum tunneling of scalar particles from black strings. For this purpose we apply WKB approximation and Hamilton-Jacobi method to solve the Klein-Gordon equation for outgoing trajectories. We find the tunneling probability of outgoing charged and uncharged scalars from the event horizon of black strings, and hence the Hawking temperature for these black configurations.
The Role of Primordial Kicks on Black Hole Merger Rates
Miroslav Micic; Tom Abel; Steinn Sigurdsson
2006-09-06
Primordial stars are likely to be very massive $\\geq30\\Msun$, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range $10^{6}-10^{10}\\Ms$. Such early black holes, at redshifts z$\\gtsim10$, could be the seed black holes for the many supermassive black holes found in galaxies in the local universe. If they exist, their mergers with nearby supermassive black holes may be a prime signal for long wavelength gravitational wave detectors. We simulate formation of black holes in the center of high redshift dark matter halos and explore implications of initial natal kick velocities conjectured by some formation models. The central concentration of early black holes in present day galaxies is reduced if they are born even with moderate kicks of tens of km/s. The modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the lower mass black holes as compared to those still embedded in their parent halos. Therefore, merger rates may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N--body simulations we quantify the role of natal kicks of black holes formed from massive metal free stars on their merger rates with supermassive black holes in present day galaxies. Our results also apply to black holes ejected by the gravitational slingshot mechanism.
Charged fermions tunneling from accelerating and rotating black holes
Rehman, Mudassar; Saifullah, K., E-mail: mudassir051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-03-01
We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.
Philips, John
1978-01-01
DETROIT TO DURBAN: BlACK \\\\OOKERS CCM1>N STRUGGLE by Blackearliest parrphlet is Detroit to Durban . Although publishedstrikes of early 1973 and the Detroit riots of 1967 is a bit
Brief review on higher spin black holes
Alfredo Perez; David Tempo; Ricardo Troncoso
2014-05-12
We review some relevant results in the context of higher spin black holes in three-dimensional spacetimes, focusing on their asymptotic behaviour and thermodynamic properties. For simplicity, we mainly discuss the case of gravity nonminimally coupled to spin-3 fields, being nonperturbatively described by a Chern-Simons theory of two independent sl(3,R) gauge fields. Since the analysis is particularly transparent in the Hamiltonian formalism, we provide a concise discussion of their basic aspects in this context; and as a warming up exercise, we briefly analyze the asymptotic behaviour of pure gravity, as well as the BTZ black hole and its thermodynamics, exclusively in terms of gauge fields. The discussion is then extended to the case of black holes endowed with higher spin fields, briefly signaling the agreements and discrepancies found through different approaches. We conclude explaining how the puzzles become resolved once the fall off of the fields is precisely specified and extended to include chemical potentials, in a way that it is compatible with the asymptotic symmetries. Hence, the global charges become completely identified in an unambiguous way, so that different sets of asymptotic conditions turn out to contain inequivalent classes of black hole solutions being characterized by a different set of global charges.
Quantum Chaos and the Black Body Radiation
Giulio Casati
2000-11-16
We discuss a mechanical model which mimics the main features of the radiation matter interaction in the black body problem. The pure classical dynamical evolution, with a simple discretization of the action variables, leads to the Stefan- Boltzmann law and to the Planck distribution without any additional statistical assumption.
Scalar Hairy Black Holes in General Dimensions
Xing-Hui Feng; H. Lu; Qiang Wen
2014-01-13
We obtain a class of asymptotic flat or (A)dS hairy black holes in D-dimensional Einstein gravity coupled to a scalar with certain scalar potential. For a given mass, the theory admits both the Schwarzschild-Tangherlini and the hairy black holes with different temperature and entropy, but satisfying the same first law of thermodynamics. For some appropriate choice of parameters, the scalar potential can be expressed in terms of a super-potential and it can arise in gauged supergravities. In this case, the solutions develop a naked curvature singularity and become the spherical domain walls. Uplifting the solutions to D=11 or 10, we obtain solutions that can be viewed as spherical M-branes or D3-branes. We also add electric charges to these hairy black holes. All these solutions contain no scalar charges in that the first law of thermodynamics are unmodified. We also try to construct new AdS black holes carrying scalar charges, with some moderate success in that the charges are pre-fixed in the theory instead of being some continuous integration constants.
Scalar Hairy Black Holes in General Dimensions
Feng, Xing-Hui; Wen, Qiang
2013-01-01
We obtain a class of asymptotic flat or (A)dS hairy black holes in D-dimensional Einstein gravity coupled to a scalar with certain scalar potential. For a given mass, the theory admits both the Schwarzschild-Tangherlini and the hairy black holes with different temperature and entropy, but satisfying the same first law of thermodynamics. For some appropriate choice of parameters, the scalar potential can be expressed in terms of a super-potential and it can arise in gauged supergravities. In this case, the solutions develop a naked curvature singularity and become the spherical domain walls. Uplifting the solutions to D=11 or 10, we obtain solutions that can be viewed as spherical M-branes or D3-branes. We also add electric charges to these hairy black holes. All these solutions contain no scalar charges in that the first law of thermodynamics are unmodified. We also try to construct new AdS black holes carrying scalar charges, with some moderate success in that the charges are pre-fixed in the theory instead ...
Bubbling supertubes and foaming black holes
Bena, Iosif; Warner, Nicholas P.
2006-09-15
We construct smooth BPS three-charge geometries that resolve the zero-entropy singularity of the U(1)xU(1) invariant black ring. This singularity is resolved by a geometric transition that results in geometries without any branes sources or singularities but with nontrivial topology. These geometries are both ground states of the black ring, and nontrivial microstates of the D1-D5-P system. We also find the form of the geometries that result from the geometric transition of N zero-entropy black rings, and argue that, in general, such geometries give a very large number of smooth bound-state three-charge solutions, parametrized by 6N functions. The generic microstate solution is specified by a four-dimensional hyper-Kaehler geometry of a certain signature, and contains a 'foam' of nontrivial two-spheres. We conjecture that these geometries will account for a significant part of the entropy of the D1-D5-P black hole, and that Mathur's conjecture might reduce to counting certain hyper-Kaehler manifolds.
Schwarzschild black hole in dark energy background
Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh
2014-09-27
In this paper we present an exact solution of Einstein's field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type $D$ in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity and the area of the horizons for the Schwarzschild-dark energy black hole.
Six Sigma Black Belts Fight For Quality
Vardeman, Stephen B.
Six Sigma Black Belts Fight For Quality Ron Scott Ross Finnestad Rodney Kalsow IE 361 mini-paper 9/22/00 #12;Six Sigma is a breakthrough management strategy that is revolutionizing the world's top corporations. So what is Six Sigma? "It is a business process that allows companies to drastically improve
Lower-Dimensional Black Hole Chemistry
Antonia M. Frassino; Robert B. Mann; Jonas R. Mureika
2015-09-18
The connection between black hole thermodynamics and chemistry is extended to the lower-dimensional regime by considering the rotating and charged BTZ metric in the $(2+1)$-D and a $(1+1)$-D limits of Einstein gravity. The Smarr relation is naturally upheld in both BTZ cases, where those with $Q \
Strains and Jets in Black Hole Fields
D. Bini; F. de Felice; A. Geralico
2007-12-14
We study the behaviour of an initially spherical bunch of particles emitted along trajectories parallel to the symmetry axis of a Kerr black hole. We show that, under suitable conditions, curvature and inertial strains compete to generate jet-like structures.
Area products for black hole horizons
Visser, Matt
2013-01-01
Area products for multi-horizon black holes often have intriguing properties, and are often independent of the mass of the black hole (depending only on various charges, angular momenta, and moduli). Such products are often formulated in terms of the areas of inner (Cauchy) horizons and event horizons, and often include the effects of unphysical "virtual'" horizons. For the Schwarzschild-de Sitter [Kottler] black hole in (3+1) dimensions it is shown by explicit exact calculation that the product of event horizon area and cosmological horizon area is not mass independent. (Including the effect of the third "virtual" horizon does not improve the situation.) Similarly, in the Reissner-Nordstrom-anti-de Sitter black hole in (3+1) dimensions the product of inner (Cauchy) horizon area and event horizon area is calculated (perturbatively), and is shown to be not mass independent. That is, the mass-independence of the product of physical horizon areas is not generic. In the generic situation, whenever the quasi-local...
Report Review Checklist a. Ink is Black
Report Review Checklist 1. General a. Ink is Black b. Margins Left & Top 1.5"; Right & Bottom 1" c. Page Numbers 1. Arabic numerals upper right corner within body of paper 2. Page Numbers: Lower case roman numerals for front matter. d. Spacing: Double spaced throughout report. e. Typeface: Arial, Times
Black Cowboys and Black Masculinity African American Ranchers, Rodeo Cowboys and Trailriders
Babers, Myeshia Chanel
2014-12-17
in the works of W. E. B. DuBois, Booker T. Washington, and Cater G. Woodson. Although disciplinary approaches, individual motivations, and prescriptions for the perceived “Negro Problem” in America vary, one common issue that scholars reproach is the idea... information about Black cowboys creates a peculiar position regarding notions, representations, and understandings about the racially signified cowboys. One common issue regarding Black identity that scholars reproach is the idea that it is pathological...
Trumpet-puncture initial data for black holes
Immerman, Jason D.; Baumgarte, Thomas W.
2009-09-15
We propose a new approach, based on the puncture method, to construct black hole initial data in the so-called trumpet geometry, i.e. on slices that asymptote to a limiting surface of nonzero areal radius. Our approach is easy to implement numerically and, at least for nonspinning black holes, does not require any internal boundary conditions. We present numerical results, obtained with a uniform-grid finite-difference code, for boosted black holes and binary black holes. We also comment on generalizations of this method for spinning black holes.
293Aqua incognita: liquor aquae superficies Aqua incognita: liquor aquae superficies
Cohen, Ronald C.
ferrocyanide exhibit "normal" ion adsorpion behavior, viz adsorption free energy changes #12;295Aqua incognita
Acoustic clouds: standing sound waves around a black hole analogue
Carolina L. Benone; Luis C. B. Crispino; Carlos Herdeiro; Eugen Radu
2015-01-28
Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.
Thermodynamic Relations for Kiselev and Dilaton Black Hole
Bushra Majeed; Mubasher Jamil; Parthapratim Pradhan
2015-08-24
We investigate the thermodynamics and phase transition for Kiselev black hole and dilaton black hole. Speci?cally we consider Reissner Nordstrom black hole surrounded by radiation and dust, and Schwarzschild black hole surrounded by quintessence, as special cases of Kiselev solution. We have calculated the products relating the surface gravities, surface temperatures, Komar energies, areas, entropies, horizon radii and the irreducible masses at the Cauchy and the event horizons. It is observed that the product of surface gravities, surface temperature product and product of Komar energies at the horizons are not universal quantities for the Kiselev solutions while products of areas and entropies at both the horizons are independent of mass of the above mentioned black holes (except for Schwarzschild black hole surrounded by quintessence). For charged dilaton black hole, all the products vanish. First law of thermodynamics is also veri?ed for Kiselev solutions. Heat capacities are calculated and phase transitions are observed, under certain conditions.
Quantization of black holes by analogy with hydrogen atoms
Chang Liu; Yan-Gang Miao; Yu-Mei Wu; Yu-Hao Zhang
2015-11-16
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Quantization of black holes by analogy with hydrogen atoms
Liu, Chang; Wu, Yu-Mei; Zhang, Yu-Hao
2015-01-01
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Quantization of black holes by analogy with hydrogen atoms
Chang Liu; Yan-Gang Miao; Yu-Mei Wu; Yu-Hao Zhang
2015-11-23
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Energy Extraction from Spinning Black Holes via Relativistic Jets
Ramesh Narayan; Jeffrey E. McClintock; Alexander Tchekhovskoy
2013-03-12
It has for long been an article of faith among astrophysicists that black hole spin energy is responsible for powering the relativistic jets seen in accreting black holes. Two recent advances have strengthened the case. First, numerical general relativistic magnetohydrodynamic simulations of accreting spinning black holes show that relativistic jets form spontaneously. In at least some cases, there is unambiguous evidence that much of the jet energy comes from the black hole, not the disk. Second, spin parameters of a number of accreting stellar-mass black holes have been measured. For ballistic jets from these systems, it is found that the radio luminosity of the jet correlates with the spin of the black hole. This suggests a causal relationship between black hole spin and jet power, presumably due to a generalized Penrose process.
The Role of Primordial Kicks on Black Hole Merger Rates
Miroslav Micic; Tom Abel; Steinn Sigurdsson
2006-09-15
Primordial stars are likely to be very massive >30 Msun, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos. We expect primordial stars to form in halos in the mass range 10^6-10^10 Msun. Some of these early black holes, formed at redshifts z>10, could be the seed black hole for a significant fraction of the supermassive black holes found in galaxies in the local universe. If the black hole descendants of the primordial stars exist, their mergers with nearby supermassive black holes may be a prime candidate for long wavelength gravitational wave detectors. We simulate formation and evolution of dark matter halos in LambdaCDM universe. We seed high-redshift dark matter halos with early black holes, and explore the merger history of the host halos and the implications of black hole's kick velocities arising from their coalescence. The central concentration of low mass early black holes in present day galaxies is reduced if they experience even moderate kicks of tens of km/s. Even such modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the low mass black holes that were ejected, compared to those still embedded in their parent halos. Therefore, merger rates with central supermassive black holes in the largest halos may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N-body simulations, we quantify the role of kicks on the merger rates of black holes formed from massive metal free stars with supermassive black holes in present day galaxies.
Hovering Black Holes from Charged Defects
Gary T. Horowitz; Nabil Iqbal; Jorge E. Santos; Benson Way
2015-05-05
We construct the holographic dual of an electrically charged, localised defect in a conformal field theory at strong coupling, by applying a spatially dependent chemical potential. We find that the IR behaviour of the spacetime depends on the spatial falloff of the potential. Moreover, for sufficiently localized defects with large amplitude, we find that a new gravitational phenomenon occurs: a spherical extremal charged black hole nucleates in the bulk: a hovering black hole. This is a second order quantum phase transition. We construct this new phase with several profiles for the chemical potential and study its properties. We find an apparently universal behaviour for the entropy of the defect as a function of its amplitude. We comment on the possible field theory implications of our results.
Astrophysical black holes in screened modified gravity
Davis, Anne-Christine; Jha, Rahul; Muir, Jessica; Gregory, Ruth E-mail: r.a.w.gregory@durham.ac.uk E-mail: jlmuir@umich.edu
2014-08-01
Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied in laboratory, cosmological, and astrophysical contexts. In this paper, we present a preliminary investigation into whether additional constraints can be provided by studying these scalar fields around black holes. By looking at the properties of a static, spherically symmetric black hole, we find that the presence of a non-uniform matter distribution induces a non-constant scalar profile in chameleon and dilaton, but not necessarily symmetron gravity. An order of magnitude estimate shows that the effects of these profiles on in-falling test particles will be sub-leading compared to gravitational waves and hence observationally challenging to detect.
Black Hole Portal into Hidden Valleys
Sergei Dubovsky; Victor Gorbenko
2010-12-13
Superradiant instability turns rotating astrophysical black holes into unique probes of light axions. We consider what happens when a light axion is coupled to a strongly coupled hidden gauge sector. In this case superradiance results in an adiabatic increase of a hidden sector CP-violating $\\theta$-parameter in a near horizon region. This may trigger a first order phase transition in the gauge sector. As a result a significant fraction of a black hole mass is released as a cloud of hidden mesons and can be later converted into electromagnetic radiation. This results in a violent electromagnetic burst. The characteristic frequency of such bursts may range approximately from 100 eV to 100 MeV.
Puncture Evolution of Schwarzschild Black Holes
J. David Brown
2008-01-15
The moving puncture method is analyzed for a single, non-spinning black hole. It is shown that the puncture region is not resolved by current numerical codes. As a result, the geometry near the puncture appears to evolve to an infinitely long cylinder of finite areal radius. The puncture itself actually remains at spacelike infinity throughout the evolution. In the limit of infinite resolution the data never become stationary. However, at any reasonable finite resolution the grid points closest to the puncture are rapidly drawn into the black hole interior by the Gamma-driver shift condition. The data can then evolve to a stationary state. These results suggest that the moving puncture technique should be viewed as a type of "natural excision".
Hybrid black-hole binary initial data
Bruno C. Mundim; Bernard J. Kelly; Yosef Zlochower; Hiroyuki Nakano; Manuela Campanelli
2010-12-04
Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class.Quant.Grav.27:114005,2010], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculation was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.
Electromagnetic Jets from Stars and Black Holes
Samuel E. Gralla; Alexandru Lupsasca; Maria J. Rodriguez
2015-04-08
We present analytic force-free solutions modeling rotating stars and black holes immersed in the magnetic field of a thin disk that terminates at an inner radius. The solutions are exact in flat spacetime and approximate in Kerr spacetime. The compact object produces a conical jet whose properties carry information about its nature. For example, the jet from a star is surrounded by a current sheet, while that of a black hole is smooth. We compute an effective resistance in each case and compare to the canonical values used in circuit models of energy extraction. These solutions illustrate all of the basic features of the Blandford-Znajek process for energy extraction and jet formation in a clean setting.
Electromagnetic Jets from Stars and Black Holes
Gralla, Samuel E; Rodriguez, Maria J
2015-01-01
We present analytic force-free solutions modeling rotating stars and black holes immersed in the magnetic field of a thin disk that terminates at an inner radius. The solutions are exact in flat spacetime and approximate in Kerr spacetime. The compact object produces a conical jet whose properties carry information about its nature. For example, the jet from a star is surrounded by a current sheet, while that of a black hole is smooth. We compute an effective resistance in each case and compare to the canonical values used in circuit models of energy extraction. These solutions illustrate all of the basic features of the Blandford-Znajek process for energy extraction and jet formation in a clean setting.
Stable gravastars - an alternative to black holes?
Matt Visser; David L. Wiltshire
2003-12-04
The "gravastar" picture developed by Mazur and Mottola is one of a very small number of serious challenges to our usual conception of a "black hole". In the gravastar picture there is effectively a phase transition at/ near where the event horizon would have been expected to form, and the interior of what would have been the black hole is replaced by a segment of de Sitter space. While Mazur and Mottola were able to argue for the thermodynamic stability of their configuration, the question of dynamic stability against spherically symmetric perturbations of the matter or gravity fields remains somewhat obscure. In this article we construct a model that shares the key features of the Mazur-Mottola scenario, and which is sufficiently simple for a full dynamical analysis. We find that there are some physically reasonable equations of state for the transition layer that lead to stability.
Phase Structure of Higher Spin Black Holes
Abhishek Chowdhury; Arunabha Saha
2015-02-12
We revisit the study of the phase structure of higher spin black holes carried out in arXiv$:1210.0284$ using the "canonical formalism". In particular we study the low as well as high temperature regimes. We show that the Hawking-Page transition takes place in the low temperature regime. The thermodynamically favoured phase changes from conical surplus to black holes and then again to conical surplus as we increase temperature. We then show that in the high temperature regime the diagonal embedding gives the appropriate description. We also give a map between the parameters of the theory near the IR and UV fixed points. This makes the "good" solutions near one end map to the "bad" solutions near the other end and vice versa.
Comparing quantum black holes and naked singularities
T. P. Singh
2000-12-21
There are models of gravitational collapse in classical general relativity which admit the formation of naked singularities as well as black holes. These include fluid models as well as models with scalar fields as matter. Even if fluid models were to be regarded as unphysical in their matter content, the remaining class of models (based on scalar fields) generically admit the formation of visible regions of finite but arbitrarily high curvature. Hence it is of interest to ask, from the point of view of astrophysics, as to what a stellar collapse leading to a naked singularity (or to a visible region of very high curvature) will look like, to a far away observer. The emission of energy during such a process may be divided into three phases - (i) the classical phase, during which matter and gravity can both be treated according to the laws of classical physics, (ii) the semiclassical phase, when gravity is treated classically but matter behaves as a quantum field, and (iii) the quantum gravitational phase. In this review, we first give a summary of the status of naked singularities in classical relativity, and then report some recent results comparing the semiclassical phase of black holes with the semiclassical phase of spherical collapse leading to a naked singularity. In particular, we ask how the quantum particle creation during the collapse leading to a naked singularity compares with the Hawking radiation from a star collapsing to form a black hole. It turns out that there is a fundamental difference between the two cases. A spherical naked star emits only about one Planck energy during its semiclassical phase, and the further evolution can only be determined by the laws of quantum gravity. This contrasts with the semiclassical evaporation of a black hole.
Electromagnetic wave scattering by Schwarzschild black holes
Luís C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira
2009-05-20
We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section, and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time.
Lagrangian perfect fluids and black hole mechanics
Vivek Iyer
1996-10-15
The first law of black hole mechanics (in the form derived by Wald), is expressed in terms of integrals over surfaces, at the horizon and spatial infinity, of a stationary, axisymmetric black hole, in a diffeomorphism invariant Lagrangian theory of gravity. The original statement of the first law given by Bardeen, Carter and Hawking for an Einstein-perfect fluid system contained, in addition, volume integrals of the fluid fields, over a spacelike slice stretching between these two surfaces. When applied to the Einstein-perfect fluid system, however, Wald's methods yield restricted results. The reason is that the fluid fields in the Lagrangian of a gravitating perfect fluid are typically nonstationary. We therefore first derive a first law-like relation for an arbitrary Lagrangian metric theory of gravity coupled to arbitrary Lagrangian matter fields, requiring only that the metric field be stationary. This relation includes a volume integral of matter fields over a spacelike slice between the black hole horizon and spatial infinity, and reduces to the first law originally derived by Bardeen, Carter and Hawking when the theory is general relativity coupled to a perfect fluid. We also consider a specific Lagrangian formulation for an isentropic perfect fluid given by Carter, and directly apply Wald's analysis. The resulting first law contains only surface integrals at the black hole horizon and spatial infinity, but this relation is much more restrictive in its allowed fluid configurations and perturbations than that given by Bardeen, Carter and Hawking. In the Appendix, we use the symplectic structure of the Einstein-perfect fluid system to derive a conserved current for perturbations of this system: this current reduces to one derived ab initio for this system by Chandrasekhar and Ferrari.
Economic aspects of black bases in Texas
Schoen, Wayne Ayron
1976-01-01
such that an optimal asphalt content for each aggregate type could be determined. Test method Tex-126-E requires that the 6-inches in diameter by 8-inches in height samples be failed in unconfined compression and from these results an optimum asphalt content... procedure and two would not. The purpose of the vacuum saturation procedure was to determine the effect of water on the black base mixtures. At present, an acceptable national standard vacuum saturation procedure does not exist. Therefore, a test...
Big Bang Nucleosynthesis and Primordial Black Holes
C. Sivaram; Kenath Arun
2010-06-28
There are ongoing efforts in detecting Hawking radiation from primordial black holes (PBH) formed during the early universe. Here we put an upper limit on the PBH number density that could have been formed prior to the big bang nucleosynthesis era, based on the constraint that the PBH evaporation energy consisting of high energy radiation not affect the observed abundances' of elements, by disintegrating the nuclei.
Interior of Black Holes and Information Recovery
Hikaru Kawai; Yuki Yokokura
2015-09-28
We analyze time evolution of a collapsing matter from a point of view that black holes evaporate by nature. We first consider a spherical thin shell that falls in the metric of an evaporating Schwarzschild black hole whose radius $a(t)$ decreases as $\\frac{da(t)}{dt}=-\\frac{2\\sigma(a(t))}{a(t)^2}$. The shell can never reach $a(t)$, but it approaches $a(t)+\\frac{2\\sigma(a(t))}{a(t)}$ in the time scale $\\sim a(t)$. Then the radiation from the hole is extremely weakened because of the large redshift caused by the shell. This time, however, the shell itself starts to radiate and exhausts energy. After that, the hole starts to radiate again. We can repeat this argument recursively because the motion of a shell in a spherically symmetric system is independent of the outside. In this way we can analyze a spherically symmetric collapsing matter with a general continuous distribution, and find that it evaporates without forming a trapped region. If the theory has considerably more species of matter fields, the trans-Planckian problems are avoided. There is a clear boundary at $r=a+\\frac{2\\sigma}{a}$ as the surface of the object. Although the matter distribution inside the object depends on the initial data, from the outside it looks almost the same as a conventional black hole. A strong angular pressure is induced by the Hawking radiation, because of which the matter loses energy when it collapses. We then discuss how the information of the matter is recovered in this picture. Next we consider a black hole that is adiabatically grown from a small one in the heat bath, and obtain the interior metric. We show that it is the self-consistent solution of $G_{\\mu\
Flip-flopping binary black holes
Carlos O. Lousto; James Healy
2015-03-14
We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of $d\\approx25M$ between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for $t=20000M$ and displays a total change in the orientation of the spin of one of the black holes from initially aligned with the orbital angular momentum to a complete anti-alignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 Post-Newtonian equations of motion and spin evolution to show that this process continuously flip-flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.
Thermodynamics and Luminosities of Rainbow Black Holes
Mu, Benrong; Yang, Haitang
2015-01-01
Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As a result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is \\textquotedblleft Gravity's rainbow", where the spacetime background felt by a test particle would depend on its energy. Focusing on the \\textquotedblleft Amelino-Camelia dispersion relation" which is $E^{2}=m^{2}+p^{2}\\left[ 1-\\eta\\left( E/m_{p}\\right) ^{n}\\right] $ with $n>0$, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of $\\eta$ and $n$ in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with $\\eta<0$ and $n\\geq2$. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute lum...
Rotating black hole solutions with quintessential energy
Toshmatov, Bobir; Ahmedov, Bobomurat
2015-01-01
Quintessential dark energy with density $\\rho$ and pressure $p$ is governed by an equation of state of the form $p=-\\omega_{q}\\rho$ with the quintessential parameter $\\omega_q\\in(-1;-1/3)$. We derive the geometry of quintessential rotating black holes, generalizing thus the Kerr spacetimes. Then we study the quintessential rotating black hole spacetimes with the special value of $\\omega_q = -2/3$ when the resulting formulae are simple and easily tractable. We show that such special spacetimes can exist for dimensionless quintessential parameter $c<1/6$ and determine the critical rotational parameter $a_0$ separating the black hole and naked singularity spacetime in dependence on the quintessential parameter $c$. For the spacetimes with $\\omega_q = 2/3$ we present the integrated geodesic equations in separated form and study in details the circular geodetical orbits. We give radii and parameters of the photon circular orbits, marginally bound and marginally stable orbits. We stress that the outer boundary o...
Adaptive Finite Elements and Colliding Black Holes
Douglas N. Arnold; Arup Mukherjee; Luc Pouly
1997-09-15
According to the theory of general relativity, the relative acceleration of masses generates gravitational radiation. Although gravitational radiation has not yet been detected, it is believed that extremely violent cosmic events, such as the collision of black holes, should generate gravity waves of sufficient amplitude to detect on earth. The massive Laser Interferometer Gravitational-wave Observatory, or LIGO, is now being constructed to detect gravity waves. Consequently there is great interest in the computer simulation of black hole collisions and similar events, based on the numerical solution of the Einstein field equations. In this note we introduce the scientific, mathematical, and computational problems and discuss the development of a computer code to solve the initial data problem for colliding black holes, a nonlinear elliptic boundary value problem posed in an unbounded three dimensional domain which is a key step in solving the full field equations. The code is based on finite elements, adaptive meshes, and a multigrid solution process. Here we will particularly emphasize the mathematical and algorithmic issues arising in the generation of adaptive tetrahedral meshes.
Probing Dark Energy with Black Hole Binaries
Laura Mersini-Houghton; Adam Kelleher
2008-08-25
The equation of state (EoS) of dark energy $w$ remains elusive despite enormous experimental efforts to pin down its value and its time variation. Yet it is the single most important handle we have in our understanding of one of the most mysterious puzzle in nature, dark energy. This letter proposes a new method for measuring the EoS of dark energy by using the gravitational waves (GW) of black hole binaries. The method described here offers an alternative to the standard way of large scale surveys. It is well known that the mass of a black hole changes due to the accretion of dark energy but at an extremely slow rate. However, a binary of supermassive black holes (SBH) radiates gravitational waves with a power proportional to the masses of these accreting stars and thereby carries information on dark energy. These waves can propagate through the vastness of structure in the universe unimpeded. The orbital changes of the binary, induced by the energy loss from gravitational radiation, receive a large contribution from dark energy accretion. This contribution is directly proportional to $(1+w)$ and is dominant for SBH binaries with separation $R \\ge 1000$ parsec, thereby accelerating the merging process for $w > -1$ or ripping the stars apart for phantom dark energy with $w < -1$. Such orbital changes, therefore $w$, can be detected with LIGO and LISA near merging time, or with X-ray and radio measurements of Chandra and VLBA experiments.
Accretion Processes On a Black Hole
Sandip K. Chakrabarti
1996-05-03
We describe astrophysical processes around a black hole keeping primarily the physics of accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of black holes. We also discuss the difference of flow properties around a black hole and a Newtonian star. In Section 2, we present past and present developments in the study of spherically accreting flows. We study the properties of Bondi flow with and without radiative transfer. In the presence of significant angular momentum, which is especially true in a binary system, matter will be accreted as a thin Keplerian disk. In Section 3, we discuss a large number of models of these disks including the more popular standard disk model. We present magnetized disk models as well. Since the angular momentum is high in these systems, rotational motion is the most dominant component compared to the radial or the vertical velocity components. In Section 4, we study thick disk models which are of low angular momentum but still have no significant radial motion. The accretion rates could be very high causing the flow to become radiation dominated and the disk to be geometrically thick. For low accretion rates, ion pressure supported disks are formed. In Section 5, we extensively discuss the properties of transonic flows which has with sub-Keplerian angular momentum. In the absence of shock discontinuities, these sub-Keplerian flows are basically advecting, similar to Bondi flows, close to the black holes, though far away they match Keplerian or sub-Keplerian disks. In presence of shocks, the post-shock flow becomes rotation dominated similar to thick disks. In Section 6, we present results of important numerical simulations of accretion flows. Significant results from the studies of evolution of viscous transonic flows are reported. In Section 7, we discuss some observational evidences of the black hole accretion. We also present a detailed model of a generalized accretion disk and present its spectra and compare with observations. In Section 8, we summarize the review and make concluding remarks.
Black Carbon Emissions by Rocket Engines Types of rocket engines Emissions
Toohey, Darin W.
Black Carbon Emissions by Rocket Engines Types of rocket engines Emissions Liquid Hydrogen. Note: Black carbon does not deplete ozone. What happens is the black carbon emissions from the rocket. Other black carbon emissions: The number one contributor to black carbon is burning biomass. Also
Thermodynamic Product Formula for Taub-NUT Black Hole
Parthapratim Pradhan
2015-08-20
We derive various important thermodynamic relations of the inner and outer horizon in the background of Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \\emph{Lorentzian geometry}. We compare these properties with the properties of Reissner Nordstr{\\o}m black hole. We compute \\emph{area product, area sum, area minus and area division} of black hole horizons. We show that they all are not universal quantities. Based on these relations, we compute the area bound of all horizons. From area bound, we derive entropy bound and irreducible mass bound for both the horizons. We further study the stability of such black hole by computing the specific heat for both the horizons. It is shown that due to negative specific heat the black hole is thermodynamically unstable. All these calculations might be helpful to understanding the nature of black hole entropy both \\emph{interior} and exterior at the microscopic level.
Thermodynamic Product Formula for Taub-NUT Black Hole
Pradhan, Parthapratim
2015-01-01
We derive various important thermodynamic relations of the inner and outer horizon in the background of Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \\emph{Lorentzian geometry}. We compare these properties with the properties of Reissner Nordstr{\\o}m black hole. We compute \\emph{area product, area sum, area minus and area division} of black hole horizons. We show that they all are not universal quantities. Based on these relations, we compute the area bound of all horizons. From area bound, we derive entropy bound and irreducible mass bound for both the horizons. We further study the stability of such black hole by computing the specific heat for both the horizons. It is shown that due to negative specific heat the black hole is thermodynamically unstable. All these calculations might be helpful to understanding the nature of black hole entropy both \\emph{interior} and exterior at the microscopic level.
Destroying Kerr-Sen black holes with test particles
Haryanto M. Siahaan
2015-12-05
By neglecting the self-force, self-energy, and radiative effects, it has been shown that an extremal or near-extremal Kerr-Newman black hole can turn to a naked singularity when it captures charged massive test particles with angular momentum. A straightforward question then arises, do charged and rotating black holes in string theory possess the same property? In this paper we adopt the Wald's gedanken experiment in an effort to destroy a Kerr-Newman black hole's horizon to the case of (near)-extremal Kerr-Sen black holes. We find that feeding a test particle into a (near)-extremal Kerr-Sen black hole could lead to a violation of the extremal bound for such black hole.
Adaptive computation of gravitational waves from black hole interactions
Philippos Papadopoulos; Edward Seidel; Lee Wild
1998-02-27
We construct a class of linear partial differential equations describing general perturbations of non-rotating black holes in 3D Cartesian coordinates. In contrast to the usual approach, a single equation treats all radiative $\\ell -m$ modes simultaneously, allowing the study of wave perturbations of black holes with arbitrary 3D structure, as would be present when studying the full set of nonlinear Einstein equations describing a perturbed black hole. This class of equations forms an excellent testbed to explore the computational issues of simulating black spacetimes using a three dimensional adaptive mesh refinement code. Using this code, we present results from the first fully resolved 3D solution of the equations describing perturbed black holes. We discuss both fixed and adaptive mesh refinement, refinement criteria, and the computational savings provided by adaptive techniques in 3D for such model problems of distorted black holes.
Thermodynamics of Charged Lovelock - AdS Black Holes
Prasobh C. B.; Jishnu Suresh; V. C. Kuriakose
2015-10-16
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime.
Galaxy bulges and their massive black holes: a review
Alister W. Graham
2015-02-17
With references to both key and oft-forgotten pioneering works, this article starts by presenting a review into how we came to believe in the existence of massive black holes at the centres of galaxies. It then presents the historical development of the near-linear (black hole)-(host spheroid) mass relation, before explaining why this has recently been dramatically revised. Past disagreement over the slope of the (black hole)-(velocity dispersion) relation is also explained, and the discovery of sub-structure within the (black hole)-(velocity dispersion) diagram is discussed. As the search for the fundamental connection between massive black holes and their host galaxies continues, the competing array of additional black hole mass scaling relations for samples of predominantly inactive galaxies are presented.
A Quantum Material Model of Static Schwarzschild Black Holes
S. -T. Sung
1997-03-16
A quantum-mechanical prescription of static Einstein field equation is proposed in order to construct the matter-metric eigen-states in the interior of a static Schwarzschild black hole where the signature of space-time is chosen as (--++). The spectrum of the quantum states is identified to be the integral multiples of the surface gravity. A statistical explanation of black hole entropy is given and a quantisation rule for the masses of Schwarzschild black holes is proposed.
Classical and Quantum Properties of Liouville Black Holes
R. B. Mann
1994-04-25
Black hole spacetimes can arise when a Liouville field is coupled to two- dimensional gravity. Exact solutions are obtained both classically and when quantum corrections due to back reaction effects are included. The black hole temperature depends upon the mass and the thermodynamic limit breaks down before evaporation of the black hole is complete, indicating that higher-loop effects must be included for a full description of the process.
A Variational Principle for Asymptotically Randall-Sundrum Black Holes
Scott Fraser; Douglas M. Eardley
2015-07-28
We prove the following variational principle for asymptotically Randall-Sundrum (RS) black holes, based on the first law of black hole mechanics: Instantaneously static initial data that extremizes the mass yields a static black hole, for variations at fixed apparent horizon area, AdS curvature length, cosmological constant, brane tensions, and RS brane warp factors. This variational principle is valid with either two branes (RS1) or one brane (RS2), and is applicable to variational trial solutions.
Thermal Fluctuations in a Charged AdS Black Hole
Pourhassan, B
2015-01-01
In this paper, we will analyze the effects of thermal fluctuations on a charged AdS black hole. This will be done by analyzing the corrections to black hole thermodynamics due to these thermal fluctuations. We will demonstrate that the entropy of this black hole get corrected by logarithmic term. We will also calculate other corrections to other important thermodynamic quantities for this black hole. Finally, we will use the corrected value of the specific heat to analyze the phase transition in this system.
Thermal Fluctuations in a Charged AdS Black Hole
B. Pourhassan; Mir Faizal
2015-08-12
In this paper, we will analyze the effects of thermal fluctuations on a charged AdS black hole. This will be done by analyzing the corrections to black hole thermodynamics due to these thermal fluctuations. We will demonstrate that the entropy of this black hole get corrected by logarithmic term. We will also calculate other corrections to other important thermodynamic quantities for this black hole. Finally, we will use the corrected value of the specific heat to analyze the phase transition in this system.
L.A. Rebellion: Creating a New Black Cinema
Sheppard, Samantha Noelle
2011-01-01
enriching and enlightening cinematic history and legacy ofalternative, and authentic cinematic depictions of BlackL.A Rebellion’s “fabulous cinematic libera- tion brought off
Noncommutative Black-Body Radiation: Implications On Cosmic Microwave Background
Amir H. Fatollahi; Maryam Hajirahimi
2006-07-12
Including loop corrections, black-body radiation in noncommutative space is anisotropic. A direct implication of possible space noncommutativity on the Cosmic Microwave Background map is argued.
Black Pine Engineering Wins Clean Energy Trust Clean Energy Challenge...
the National Clean Energy Business Plan Competition Explore the Energy Innovation Portal Last week the student team of Black Pine Engineering from Michigan State University...
Modelled Black Carbon Radiative Forcing and Atmospheric Lifetime...
Office of Scientific and Technical Information (OSTI)
AeroCom Phase II Constrained by Aircraft Observations Black carbon (BC) aerosols absorb solar radiation, and are generally held to exacerbate global warming through exerting a...
Lovelock black hole thermodynamics in a string cloud model
Lee, Tae-Hun; Maharaj, Sunil D; Baboolal, Dharmanand
2015-01-01
The Lovelock theory is an extension of general relativity to higher dimensions. We study the Lovelock black hole for a string cloud model in arbitrary dimensional spacetime, and in turn also analyze its thermodynamical properties. Indeed, we compute the mass, temperature and entropy of the black hole and also perform a thermodynamical stability analysis. The phase structure suggests that the Hawking-Page phase transition is achievable. It turns out that the presence of the Lovelock terms and/or background string cloud completely changes the black hole thermodynamics. Interestingly, the entropy of a black hole is unaffected due to a background string cloud, but has a correction term due to Lovelock gravity.
Thermodynamics of rotating black holes in conformal gravity
Kamvar, Negin; Soroushfar, Saheb
2015-01-01
In this paper we consider a metric of a rotating black hole in conformal gravity. We calculate the thermodynamical quantities for this rotating black hole including Hawking temperature and entropy in four dimensional space-time, as we obtain the effective value of Komar angular momentum. The result is valid on the event horizon of the black hole, and at any radial distance out of it. Also we verify that the first law of thermodynamics will be held for this type of black hole.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Benrong Mu; Peng Wang; Haitang Yang
2015-01-24
In this paper, we investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Mu, Benrong; Yang, Haitang
2015-01-01
In this paper, we investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Energy Distribution of a Charged Regular Black Hole
Irina Radinschi
2000-11-20
We calculate the energy distribution of a charged regular black hole by using the energy-momentum complexes of Einstein and M{\\o}ller.
Paleoecology of the Devonian-Mississippian black-shale sequence...
Office of Scientific and Technical Information (OSTI)
54 ENVIRONMENTAL SCIENCES; 03 NATURAL GAS; 04 OIL SHALES AND TAR SANDS; BLACK SHALES; GEOLOGY; PALEONTOLOGY; KENTUCKY; DEVONIAN PERIOD; FOSSILS; GEOLOGIC HISTORY; BITUMINOUS...
Free fall onto evaporating black holes at the quantum limit
Maurice H. P. M. van Putten
2015-11-11
Black hole space times evaporate in discrete steps due to remarkably slow Hawking radiation. We here identify evaporation with essentially extremal states at the limit of quantum computation, performing $2.7\\times 10^{79}$ bit calculations per photon emission in a one solar mass black hole. During evaporation, particles in free fall co-evolve satisfying $EM=$constant, where $E$ and $M$ denote the total mass energy-at-infinity of the particle and, respectively, black hole. Particles are hereby increasingly entangled with the black hole space-time over the course of its evaporation.
T-602: BlackBerry Enterprise Server Input Validation Flaw in...
Broader source: Energy.gov (indexed) [DOE]
BlackBerry Enterprise Server Input Validation Flaw in BlackBerry Web Desktop Manager Permits Cross-Site Scripting Attacks PLATFORM: BlackBerry Enterprise Server Express versions...
Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices
Coppola, Alysha; Ziolkowski, L. A.; Druffel, E. R. M.
2013-01-01
rived (black/elemental) carbon in soils and sediments usingbon measurements of black carbon in aerosols and oceanMWI, Noack AG. 2000. Black carbon in soils and sediments:
T-579: BlackBerry Device Software Bug in WebKit Lets Remote Users...
Broader source: Energy.gov (indexed) [DOE]
information stored on the file system of the BlackBerry smartphone. The following devices are affected: * BlackBerry Bold 9650 smartphone * BlackBerry Bold 9700 smartphone...
I am Black AND Jewish: Black Jewish Women’s Experiences in “White” Jewish Communities in Brazil
Gondek, Abby S.
2008-01-01
ideal after scientific racism. Black into white: Race andbut continues to enact racism and anti-Semitism (Barcelos,context demonstrates why racism (including anti-Semitism) is
Inheritance of Black Pericarp Trait in Sorghum
Hill, Kathleen Marie
2014-09-18
high and low pH levels, making it a viable candidate for use as a natural food colorant and preservative (Pfeiffer, 2014). Sorghum is also naturally gluten free (Pfeiffer, 2014) making it an excellent wheat substitute for those who suffer from Celiac... as antioxidants (Dlamini et al., 2007) and in the body, ward off free radicals that lead to disease (Rajendran, et. al., 2014). Sorghum, 5 compared to other cereals, has the highest level of antioxidants (Pfeiffer, 2014). In fact, black sorghum has levels...
Radion clouds around evaporating black holes
J. R. Morris
2009-09-03
A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.
Black Kernel and White Tip of Rice.
Martin, Alan L. (Alan La Mott); Altstatt, G. E. (George E.)
1940-01-01
. Amer. Jour. Bot. 26 :P46-852. 1939. Taubenhaus, J. J. Rice diseases. In 50th Ann. Rpt. Tex. Agr. Sta., pp. 114-115. 1937. Taubenhaus, J. J., Altstatt, G. E., and Wyche, R. H. Black kernel of rice. In 4Fth Ann. Rpt. Texas Am. Exp. Sta., p. 94. 1935.... Taubenhaus, J. J., and Wyche, R. H. Rice Diseases. In 49th Ann. Rpt. Texas Agr. Exp. Sta., pp. 109-111. 1936. Tullis, E. C. Fungi isolated from discolored rice kernels. U. S. Dept. Agr. Tech. Bull. 540. 1936. ...
Black Hills Power Inc | Open Energy Information
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 Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmental JumpInformationBio-Gas Technologies, LLCMichigan:Earth, Wisconsin:Black Hills
BlackGold Biofuels | Open Energy Information
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Cemex Black Mountain Quarry | Open Energy Information
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 Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButte County,Camilla,Thermal Gradient Holes JumpHills WindBlack Mountain Quarry
Paleoecology and Geochemistry of the Upper Kellwasser Black Shale and Extinction Event
Haddad, Emily Elizabeth
2015-01-01
A.D. , 2009. When do black shales tell molybdenum isotopeand redox facies in core shales of Upper PennsylvanianB.B. , 1994. Marine black shales: depositional mechanisms
Exact quasinormal modes for a special class of black holes
Julio Oliva; Ricardo Troncoso
2010-03-11
Analytic exact expressions for the quasinormal modes of scalar and electromagnetic perturbations around a special class of black holes are found in d\\ge3 dimensions. It is shown that, the size of the black hole provides a bound for the angular momentum of the perturbation. Quasinormal modes appear when this bound is fulfilled, otherwise the excitations become purely damped.
Moduli Vacuum Bubbles Produced by Evaporating Black Holes
J. R. Morris
2007-08-14
We consider a model with a toroidally compactified extra dimension giving rise to a temperature-dependent 4d effective potential with one-loop contributions due to the Casimir effect, along with a 5d cosmological constant. The forms of the effective potential at low and high temperatures indicates a possibility for the formation of a domain wall bubble, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum bubble arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys. Rev. D74, 024004 (2006), arXiv:hep-th/0605047]. The black hole bubble can be highly opaque to lower energy particles and photons, and thereby entrap them within. For high temperature black holes, there may also be a symmetry-breaking black hole bubble of false vacuum of the type previously conjectured by Moss [I.G. Moss, Phys. Rev. D32,1333 (1985)], tending to reflect low energy particles from its wall. A double bubble composed of these two different types of bubble may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum bubbles behind that contribute to the dark matter.
Modified Black Hole with Polar Jet and Vortex
T. Tmmalm
2001-12-06
There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.
Pair Production of Topological anti de Sitter Black Holes
R. B. Mann
1996-07-28
The pair creation of black holes with event horizons of non-trivial topology is described. The spacetimes are all limiting cases of the cosmological $C$ metric. They are generalizations of the $(2+1)$ dimensional black hole and have asymptotically anti de Sitter behaviour. Domain walls instantons can mediate their pair creation for a wide range of mass and charge.
Analysis of spherically symmetric black holes in Braneworld models
A. B. Pavan
2010-05-25
Research on black holes and their physical proprieties has been active on last 90 years. With the appearance of the String Theory and the Braneworld models as alternative descriptions of our Universe, the interest on black holes, in these context, increased. In this work we studied black holes in Braneworld models. A class of spherically symmetric black holes is investigaded as well its stability under general perturbations. Thermodynamic proprieties and quasi-normal modes are discussed. The black holes studied are the SM (zero mass) and CFM solutions, obtained by Casadio {\\it et al.} and Bronnikov {\\it et al.}. The geometry of bulk is unknown. However the Campbell-Magaard Theorem guarantees the existence of a 5-dimensional solution in the bulk whose projection on the brane is the class of black holes considered. They are stable under scalar perturbations. Quasi-normal modes were observed in both models. The tail behavior of the perturbations is the same. The entropy upper bound of a body absorved by the black holes studied was calculated. This limit turned out to be independent of the black hole parameters.
Perturbative Approach to the Quasinormal Modes of Dirty Black Holes
P. T. Leung; Y. T. Liu; W. -M. Suen; C. Y. Tam; K. Young
1999-03-08
Using a recently developed perturbation theory for uasinormal modes (QNM's), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation.
Gravitational wave production by rotating primordial black holes
Dong, Ruifeng; Stojkovic, Dejan
2015-01-01
In this paper we analyze in detail a rarely discussed question of gravity waves production from evaporating black holes. Evaporating black holes emit gravitons which are at classical level registered as gravity waves. We use the latest constraints on the primordial black hole abundance, and calculate the power emitted in gravitons at the time of their evaporation. We then solve the coupled system of equations that gives us the evolution of the frequency and amplitude of gravity waves during the expansion of the universe. The spectrum of gravitational waves that can be detected today depends on multiple factors: fraction of the total energy density which was occupied by black holes, the epoch in which the black holes are formed, and quantities like mass and angular momentum of evaporating black holes. We conclude that very small primordial black holes which evaporate before the nucleosynthesis emit gravitons whose spectral energy fraction today can be as large as $10^{-5}$. On the other hand, primordial black ...
Accretion onto the First Stellar Mass Black Holes
Marcelo A. Alvarez; John H. Wise; Tom Abel
2008-11-07
The first stars in the universe, forming at redshifts z>15 in minihalos with masses of order 10^6 Msun, may leave behind black holes as their remnants. These objects could conceivably serve as "seeds" for much larger black holes observed at redshifts z~6. We study the growth of the remnant black holes through accretion including for the first time the emitted accretion radiation with adaptive mesh refinement cosmological radiation-hydrodynamical simulations. The effects of photo-ionization and heating dramatically affect the accretion flow from large scales, resulting in negligible mass growth of the black hole. We compare cases with the accretion luminosity included and neglected to show that the accretion radiation drastically changes the environment within 100 pc of the black hole, where gas temperatures are increased by an order of magnitude. The gas densities are reduced and further star formation in the same minihalo prevented for the two hundred million years of evolution we followed. These calculations show that even without the radiative feedback included most seed black holes do not gain mass as efficiently as has been hoped for in previous theories, implying that black hole remnants of Pop III stars that formed in minihalos are not likely to be the origin of miniquasars. Most importantly, however, these calculations demonstrate that if early stellar mass black holes are indeed accreting close to the Bondi-Hoyle rate with ten percent efficiency they have a dramatic local effect in regulating star formation in the first galaxies.
Large rotating AdS black holes from fluid mechanics
Sayantani Bhattacharyya; Subhaneil Lahiri; R. Loganayagam; Shiraz Minwalla
2008-07-25
We use the AdS/CFT correspondence to argue that large rotating black holes in global AdS(D) spaces are dual to stationary solutions of the relativistic Navier-Stokes equations on S**(D-2). Reading off the equation of state of this fluid from the thermodynamics of non-rotating black holes, we proceed to construct the nonlinear spinning solutions of fluid mechanics that are dual to rotating black holes. In all known examples, the thermodynamics and the local stress tensor of our solutions are in precise agreement with the thermodynamics and boundary stress tensor of the spinning black holes. Our fluid dynamical description applies to large non-extremal black holes as well as a class of large non-supersymmetric extremal black holes, but is never valid for supersymmetric black holes. Our results yield predictions for the thermodynamics of all large black holes in all theories of gravity on AdS spaces, for example, string theory on AdS(5) x S**5 and M theory on AdS(4) x S**7 and AdS(7) x S**4.
Electric Charge in Interaction with Magnetically Charged Black Holes
J. H. Kim; Sei-Hoon Moon
2007-10-02
We examine the angular momentum of an electric charge e placed at rest outside a dilaton black hole with magnetic charge Q. The electromagnetic angular momentum which is stored in the electromagnetic field outside the black hole shows several common features regardless of the dilaton coupling strength, though the dilaton black holes are drastically different in their spacetime structure depending on it. First, the electromagnetic angular momentum depends on the separation distance between the two objects and changes monotonically from eQ to 0 as the charge goes down from infinity to the horizon, if rotational effects of the black hole are discarded. Next, as the black hole approaches extremality, however, the electromagnetic angular momentum tends to be independent of the distance between the two objects. It is then precisely $eQ$ as in the electric charge and monopole system in flat spacetime. We discuss why these effects are exhibited and argue that the above features are to hold in widely generic settings including black hole solutions in theories with more complicated field contents, by addressing the no hair theorem for black holes and the phenomenon of field expulsion exhibited by extremal black holes.
A note on regular black holes in a brane world
Neves, J C S
2015-01-01
In this work, we show that regular black holes in a Randall-Sundrum-type brane world model are generated by the non-local bulk influence, expressed by a constant parameter in the brane metric, only in the spherical case. In the axial case (black holes with rotation), this influence forbids them.
Pseudomonas sabulinigri sp. nov., isolated from black beach sand
Bae, Jin-Woo
Pseudomonas sabulinigri sp. nov., isolated from black beach sand Kyoung-Ho Kim,1 Seong Woon Roh,1 , was isolated from black sand collected from Soesoggak, Jeju Island, Korea. Cells grew at 4Â37 6C, at pH 5 beach sand, a bacterium was isolated and subjected to taxonomic characterization. On the basis
Accretion Disks Around Black Holes: Twenty Five Years Later
Sandip K. Chakrabarti
1998-07-10
We study the progress of the theory of accretion disks around black holes in last twenty five years and explain why advective disks are the best bet in explaining varied stationary and non-stationary observations from black hole candidates. We show also that the recently proposed advection dominated flows are incorrect.
Extracting Energy from Black Hole through Transition Region
Li-Xin Li
2000-07-24
A new scenario for extracting energy from a Kerr black hole is proposed. With magnetic field lines connecting plasma particles inside the ergosphere with remote loads, the frame dragging twists the field lines so that energy and angular momentum are extracted from the plasma particles. If the magnetic field is strong enough, the energy extracted from the particles can be so large that the particles have negative energy as they fall into the black hole. So effectively the energy is extracted from the black hole. The particles inside the ergosphere can be continuously replenished with accretion from a disk surrounding the black hole, so a transition region with sufficient amount of plasma is formed between the black hole's horizon and the inner edge of the disk. Thus the energy can be continuously extracted from the black hole through the transition region. This may be the most efficient way for extracting energy from a Kerr black hole: in principle almost all of the rotational energy (up to $\\approx 29%$ of the total energy of the black hole) can be extracted.
Electromagnetic Excitation of Rotating Black Holes and Relativistic Jets
A. Burinskii; E. Elizalde; S. R. Hildebrandt; G. Magli
2006-10-02
We show that electromagnetic excitations of rotating black holes can lead to the appearance of narrow singular beams which break up the black hole horizon forming a tube-like region which connects the interior and exterior. It is argued that this effect may be at the origin of jet formation.
Is the Universe the only existing Black Hole?
Andrea Gregori
2010-06-30
We investigate the physics of black holes in the light of the quantum theoretical framework proposed in [1]. It is argued that black holes are completely non-local objects, and that the only one which really exists is the universe itself.
Hadrons As Kerr-Newman Black Holes
R. L. Oldershaw
2010-03-15
The scale invariance of the source-free Einstein field equations suggests that one might be able to model hadrons as "strong gravity" black holes, if one uses an appropriate rescaling of units or a revised gravitational coupling factor. The inner consistency of this hypothesis is tested by retrodicting a close approximation to the mass of the proton from an equation that relates the angular momentum and mass of a Kerr black hole. More accurate mass and radius values for the proton are then retrodicted using the geometrodynamics form of the full Kerr-Newman solution of the Einstein-Maxwell equations. The radius of an alpha particle is calculated as an additional retrodictive test. In a third retrodictive test of the "strong gravity" hypothesis, the subatomic particle mass spectrum in the 100 MeV to 7,000 MeV range is retrodicted to a first approximation using the Kerr solution of General Relativity. The particle masses appear to form a restricted set of quantized values of the Kerr solution: n^1/2 M, where values of n are a set of discrete integers and M is the revised Planck mass. The accuracy of the 27 retrodicted masses averages 98.4%. Finally, the new atomic scale gravitational coupling constant suggests a radical revision of the assumptions governing the Planck scale, and leads to a natural explanation for the fine structure constant.
Probing the puncture for black hole simulations
J. David Brown
2009-10-23
With the puncture method for black hole simulations, the second infinity of a wormhole geometry is compactified to a single "puncture point" on the computational grid. The region surrounding the puncture quickly evolves to a trumpet geometry. The computational grid covers only a portion of the trumpet throat. It ends at a boundary whose location depends on resolution. This raises the possibility that perturbations in the trumpet geometry could propagate down the trumpet throat, reflect from the puncture boundary, and return to the black hole exterior with a resolution--dependent time delay. Such pathological behavior is not observed. This is explained by the observation that some perturbative modes propagate in the conformal geometry, others propagate in the physical geometry. The puncture boundary exists only in the physical geometry. The modes that propagate in the physical geometry are always directed away from the computational domain at the puncture boundary. The finite difference stencils ensure that these modes are advected through the boundary with no coupling to the modes that propagate in the conformal geometry. These results are supported by numerical experiments with a code that evolves spherically symmetric gravitational fields with standard Cartesian finite difference stencils. The code uses the Baumgarte--Shapiro--Shibata--Nakamura formulation of Einstein's equations with 1+log slicing and gamma--driver shift conditions.
BLACK HOLE FORAGING: FEEDBACK DRIVES FEEDING
Dehnen, Walter; King, Andrew, E-mail: wd11@leicester.ac.uk, E-mail: ark@astro.le.ac.uk [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)] [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)
2013-11-10
We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy, but little angular momentum to the surrounding gas. Once central accretion drops, the feedback weakens and swept-up gas falls back toward the SMBH on near-parabolic orbits. These intersect near the black hole with partially opposed specific angular momenta, causing further infall and ultimately the formation of a small-scale accretion disk. The feeding rates into the disk typically exceed Eddington by factors of a few, growing the hole on the Salpeter timescale and stimulating further feedback. Natural consequences of this picture include (1) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (2) random orientations of successive accretion disk episodes; (3) the possibility of rapid SMBH growth; (4) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible flares and ejection of hypervelocity stars; (5) super-solar abundances of the matter accreting on to the SMBH; and (6) a lower central dark-matter density, and hence annihilation signal, than adiabatic SMBH growth implies. We also suggest a simple subgrid recipe for implementing this process in numerical simulations.
Extremal Limits of Rotating Black Holes
Laura Andrianopoli; Riccardo D'Auria; Antonio Gallerati; Mario Trigiante
2013-05-30
We consider non-extremal, stationary, axion-dilaton solutions to ungauged symmetric supergravity models, obtained by Harrison transformations of the non-extremal Kerr solution. We define a general algebraic procedure, which can be viewed as an Inonu-Wigner contraction of the Noether charge matrix associated with the effective D=3 sigma-model description of the solution, yielding, through different singular limits, the known BPS and non-BPS extremal black holes (which include the under-rotating non-BPS one). The non-extremal black hole can thus be thought of as "interpolating" among these limit-solutions. The algebraic procedure that we define generalizes the known Rasheed-Larsen limit which yielded, in the Kaluza-Klein theory, the first instance of under-rotating extremal solution. As an example of our general result, we discuss in detail the non-extremal solution in the T^3-model, with either (q_0, p^1) or (p^0, q_1) charges switched on, and its singular limits. Such solutions, computed in D=3 through the solution-generating technique, is completely described in terms of D=4 fields, which include the fully integrated vector fields.
Quasinormal modes of test fields around regular black holes
Bobir Toshmatov; Ahmadjon Abdujabbarov; Zden?k Stuchlík; Bobomurat Ahmedov
2015-04-25
We study scalar, electromagnetic and gravitational test fields in the Hayward, Bardeen and Ay\\'on-Beato-Garc\\'ia regular black hole spacetimes and demonstrate that the test fields are stable in all these spacetimes. Using the sixth order WKB approximation of the linear "axial" perturbative scheme, we determine dependence of the quasinormal mode (QNM) frequencies on the characteristic parameters of the test fields and the spacetime charge parameters of the regular black holes. We give also the greybody factors, namely the transmission and reflection coefficients of scattered scalar, electromagnetic and gravitational waves. We show that damping of the QNMs in regular black hole spacetimes is suppressed in comparison to the case of Schwarzschild black holes, and increasing charge parameter of the regular black holes increases reflection and decreases transmission factor of incident waves for each of the test fields.
Hypervelocity binary stars: smoking gun of massive binary black holes
Youjun Lu; Qingjuan Yu; D. N. C. Lin
2007-07-22
The hypervelocity stars recently found in the Galactic halo are expelled from the Galactic center through interactions between binary stars and the central massive black hole or between single stars and a hypothetical massive binary black hole. In this paper, we demonstrate that binary stars can be ejected out of the Galactic center with velocities up to 10^3 km/s, while preserving their integrity, through interactions with a massive binary black hole. Binary stars are unlikely to attain such high velocities via scattering by a single massive black hole or through any other mechanisms. Based on the above theoretical prediction, we propose a search for binary systems among the hypervelocity stars. Discovery of hypervelocity binary stars, even one, is a definitive evidence of the existence of a massive binary black hole in the Galactic center.
Weighing Black Holes in high-z SCUBA Galaxies
Alexander, D M
2006-01-01
Deep SCUBA surveys have uncovered a population of dust-enshrouded star-forming galaxies at z~2. Using the ultra-deep 2 Ms Chandra Deep Field-North survey we recently showed that a large fraction of these systems are also undergoing intense black-hole growth. Here we provide further constraints on the properties of the black holes in SCUBA galaxies using the virial black-hole mass estimator. We show that typical SCUBA galaxies are likely to host black holes with M_BH~10^7-10^8 M_solar which are accreting at, or close to, the Eddington limit. These results provide qualitative support for our earlier conclusion that the growth of the black hole lags that of the host galaxy in these massive ultraluminous galaxies.
Brian Kong; Youngsub Yoon
2015-04-14
By pointing out an error in the previous derivation of the area spectrum based on Ashtekar's variables, we suggest a new area spectrum; in the previous derivation of the area spectrum, area operator is expressed in terms of Levi-Civita symbol instead of Levi-Civita tensor, which should have been used. At first glance, this consideration may not seem to make any difference in the actual area spectrum, but upon quantization it yields a difference, as classical equivalence doesn't always imply quantum equivalence. For this purpose, we construct our "newer" variables. In particular, our "newer" variables are mathematically consistent; the constraint algebra is closed. Moreover, by using our new area spectrum, we "almost correctly" predict the Bekenstein-Hawking entropy without adjusting Immirzi parameter; we show that a numerical formula actually turned out to be $0.997\\cdots$ which is very close to 1, the expected value with the black hole entropy given as $A/4$. We conjecture that the difference, 0.003, is due to the extra dimensions which may modify the area spectrum. Then, we derive a formula for the degeneracy for a single-partition black hole, (i.e. black hole made out of single unit area) and explicitly show that our area spectrum correctly reproduces the degeneracy. Furthermore, by two totally different methods, we obtain the proportionality constant "$C$" related to the degeneracy. The first method based on fitting yields 172$\\sim$173, while the second method yields 172.87$\\cdots$, which strongly suggest that our area spectrum is on the right track. We also show that the area spectrums based on Ashtekar variables neither reproduces the degeneracy of single-partition black hole nor yields the agreement for $C$ obtained by the two methods.
Charged black holes in generalized teleparallel gravity
Rodrigues, M.E.; Houndjo, M.J.S.; Tossa, J.; Momeni, D.; Myrzakulov, R. E-mail: sthoundjo@yahoo.fr E-mail: d.momeni@yahoo.com
2013-11-01
In this paper we investigate charged static black holes in 4D for generalized teleparallel models of gravity, based on torsion as the geometric object for describing gravity according to the equivalence principle. As a motivated idea, we introduce a set of non-diagonal tetrads and derive the full system of non linear differential equations. We prove that the common Schwarzschild gauge is applicable only when we study linear f(T) case. We reobtain the Reissner-Nordstrom-de Sitter (or RN-AdS) solution for the linear case of f(T) and perform a parametric cosmological reconstruction for two nonlinear models. We also study in detail a type of the no-go theorem in the framework of this modified teleparallel gravity.
Bubbling the Newly Grown Black Ring Hair
Vasilakis, Orestis
2012-01-01
New families of BPS black ring solutions with four electric and four dipole magnetic charges have recently been explicitly constructed and uplifted to M-theory. These solutions were found to belong to a CFT with central charge different compared to the one of the STU model. Because of their importance to AdS/CFT, here we give the microstate description of these geometries in terms of topological bubbles and supertubes. The fourth charge results in an additional flux through the topological cycles that resolve the brane singularities. The analog of these solutions in the IIB frame yield a generalized regular supertube with three electric charges and one dipole charge. Direct comparison is also made with the previously-known bubbled geometries.
Bubbling the Newly Grown Black Ring Hair
Orestis Vasilakis
2012-02-08
New families of BPS black ring solutions with four electric and four dipole magnetic charges have recently been explicitly constructed and uplifted to M-theory. These solutions were found to belong to a CFT with central charge different compared to the one of the STU model. Because of their importance to AdS/CFT, here we give the microstate description of these geometries in terms of topological bubbles and supertubes. The fourth charge results in an additional flux through the topological cycles that resolve the brane singularities. The analog of these solutions in the IIB frame yield a generalized regular supertube with three electric charges and one dipole charge. Direct comparison is also made with the previously-known bubbled geometries.
Black hole thermodynamics in finite time
Gruber, Christine
2016-01-01
Finite-time thermodynamics provides the means to revisit ideal thermodynamic equilibrium processes in the light of reality and investigate the energetic "price of haste", i.e. the consequences of carrying out a process in finite time, when perfect equilibrium cannot be awaited due to economic reasons or the nature of the process. Employing the formalism of geometric thermodynamics, a lower bound on the energy dissipated during a process is derived from the thermodynamic length of that process. The notion of length is hereby defined via a metric structure on the space of equilibrium thermodynamics, spanned by a set of thermodynamic variables describing the system. Since the aim of finite-time thermodynamics is to obtain realistic limitations on idealized scenarios, it is a useful tool to reassess the efficiency of thermodynamic processes. We examine its implications for black hole thermodynamics, in particular scenarios inspired by the Penrose process, a thought experiment by which work can be extracted from a...
Collisions with Black Holes and Deconfined Plasmas
Amsel, Aaron J; Virmani, Amitabh
2008-01-01
We use AdS/CFT to investigate i) high energy collisions with balls of deconfined plasma surrounded by a confining phase and ii) the rapid localized heating of a deconfined plasma. Both of these processes are dual to collisions with black holes, where they result in the nucleation of a new "arm" of the horizon reaching out in the direction of the incident object. We study the resulting non-equilibrium dynamics in a universal limit of the gravitational physics which may indicate universal behavior of deconfined plasmas at large N_c. Process (i) produces "virtual" arms of the plasma ball, while process (ii) can nucleate surprisingly large bubbles of a higher temperature phase.
Collisions with Black Holes and Deconfined Plasmas
Aaron J. Amsel; Donald Marolf; Amitabh Virmani
2007-12-13
We use AdS/CFT to investigate i) high energy collisions with balls of deconfined plasma surrounded by a confining phase and ii) the rapid localized heating of a deconfined plasma. Both of these processes are dual to collisions with black holes, where they result in the nucleation of a new "arm" of the horizon reaching out in the direction of the incident object. We study the resulting non-equilibrium dynamics in a universal limit of the gravitational physics which may indicate universal behavior of deconfined plasmas at large N_c. Process (i) produces "virtual" arms of the plasma ball, while process (ii) can nucleate surprisingly large bubbles of a higher temperature phase.
Thermodynamic Product Formula for Ho?ava Lifshitz Black Hole
Parthapratim Pradhan
2015-06-10
We examine the thermodynamic properties of inner and outer horizons in the background of Ho\\v{r}ava Lifshitz black hole. We compute the \\emph{horizon radii product, the surface area product, the entropy product, the surface temperature product, the Komar energy product and the specific heat product} for both the horizons of said black hole. We show that surface area product, entropy product and irreducible mass product are \\emph{universal} quantities, whereas the surface temperature product, Komar energy product and specific heat product are \\emph{not universal} quantities because they all are depends on mass parameter. We also observe that the \\emph{First law} of black hole thermodynamics and \\emph {Smarr-Gibbs-Duhem } relations do not hold for this black hole. The underlying reason behind this failure due to the scale invariance of the coupling constant. We further derive the \\emph{Smarr mass formula} and \\emph{Christodolou-Ruffini mass formula} for such black hole spacetime. Moreover we study the stability of such black hole by computing the specific heat for both the horizons. It has been observed that under certain condition the black hole possesses second order phase transition.
Varying fine structure 'constant' and charged black holes
Bekenstein, Jacob D.; Schiffer, Marcelo
2009-12-15
Speculation that the fine-structure constant {alpha} varies in spacetime has a long history. We derive, in 4-D general relativity and in isotropic coordinates, the solution for a charged spherical black hole according to the framework for dynamical {alpha} J. D. Bekenstein, Phys. Rev. D 25, 1527 (1982).. This solution coincides with a previously known one-parameter extension of the dilatonic black hole family. Among the notable properties of varying-{alpha} charged black holes are adherence to a 'no hair' principle, the absence of the inner (Cauchy) horizon of the Reissner-Nordstroem black holes, the nonexistence of precisely extremal black holes, and the appearance of naked singularities in an analytic extension of the relevant metric. The exteriors of almost extremal electrically (magnetically) charged black holes have simple structures which makes their influence on applied magnetic (electric) fields transparent. We rederive the thermodynamic functions of the modified black holes; the otherwise difficult calculation of the electric potential is done by a shortcut. We confirm that variability of {alpha} in the wake of expansion of the universe does not threaten the generalized second law.
The Evolution of Accreting Black Holes in Outburst
John A. Tomsick
2004-01-12
Black hole binaries exhibit dramatic changes in their X-ray spectral and timing properties over time, providing important clues about the physical processes that occur in these systems. Black holes and black hole candidates are prime targets for RXTE with observational goals including the study of extreme gravitational fields and jet formation mechanisms. The great wealth of data from RXTE has helped us to learn about these systems as well as raising new questions about accreting black holes. RXTE observations have allowed us to study a wide range of black hole science topics including the connection between the accretion disk and jets, the geometry of the inner accretion flow, and the physical changes that occur between spectral states. In this presentation, I discuss significant results on these topics that have been obtained for persistent and transient black holes over the past several years, and I present results from our program of X-ray and radio observations during the decays of black hole transient outbursts.
Hybrid method for understanding black-hole mergers: Inspiralling case
David A. Nichols; Yanbei Chen
2012-02-21
We adapt a method of matching post-Newtonian and black-hole-perturbation theories on a timelike surface (which proved useful for understanding head-on black-hole-binary collisions) to treat equal-mass, inspiralling black-hole binaries. We first introduce a radiation-reaction potential into this method, and we show that it leads to a self-consistent set of equations that describe the simultaneous evolution of the waveform and of the timelike matching surface. This allows us to produce a full inspiral-merger-ringdown waveform of the l=2, m=2,-2 modes of the gravitational waveform of an equal-mass black-hole-binary inspiral. These modes match those of numerical-relativity simulations well in phase, though less well in amplitude for the inspiral. As a second application of this method, we study a merger of black holes with spins antialigned in the orbital plane (the "superkick" configuration). During the ringdown of the superkick, the phases of the mass- and current-quadrupole radiation become locked together, because they evolve at the same quasinormal mode frequencies. We argue that this locking begins during merger, and we show that if the spins of the black holes evolve via geodetic precession in the perturbed black-hole spacetime of our model, then the spins precess at the orbital frequency during merger. In turn, this gives rise to the correct behavior of the radiation, and produces a kick similar to that observed in numerical simulations.
Stability of black holes based on horizon thermodynamics
Meng-Sen Ma; Ren Zhao
2015-11-11
On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss-Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables $E,P,V,T,S$. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, $P=P(V,T)$. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that $P>0$ is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss-Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.
Higgs Boson Production from Black Holes at the LHC
Gouranga C. Nayak; J. Smith
2006-06-09
If the fundamental Planck scale is near a TeV, then TeV scale black holes should be produced in proton-proton collisions at the LHC where \\sqrt{s} = 14 TeV. As the temperature of the black holes can be ~ 1 TeV we also expect production of Higgs bosons from them via Hawking radiation. This is a different production mode for the Higgs boson, which would normally be produced via direct pQCD parton fusion processes. In this paper we compare total cross sections and transverse momentum distributions d\\sigma/dp_T for Higgs production from black holes at the LHC with those from direct parton fusion processes at next-to-next-to-leading order and next-to-leading order respectively. We find that the Higgs production from black holes can be larger or smaller than the direct pQCD production depending upon the Planck mass and black hole mass. We also find that d\\sigma/dp_T of Higgs production from black holes increases as a function of p_T which is in sharp contrast with the pQCD predictions where d\\sigma/dp_T decreases so we suggest that the measurement of an increase in d\\sigma/dp_T as p_T increases for Higgs (or any other heavy particle) production can be a useful signature for black holes at the LHC.
Selmic, Sandra
Black Belt Certification A Louisiana Tech University Six Sigma Black Belt certification can be obtained, STAT 507 Design and Analysis of Experiments, and INEN 557 Six Sigma Black Belt Project with a B the Louisiana Tech University Six Sigma Black Belt certification. INEN 514 is offered in the fall and spring
Black Hole Thermodynamic Products in Einstein Gauss Bonnet Gravity
Mandal, Abhijit
2015-01-01
We study the thermodynamic properties of black hole horizons in Einstein Gauss Bonnet gravity. We derive the thermodynamic products of characteristic parameters to mark which are global. We further interpret the stability of the black holes by computing the specific heat for both horizons. Stable and unstable phases of horizons are pointed out. The phase transitions with respect to the charge in nature of specific heat are also observed. All these calculation might be helpful to understand the microscopic nature of such black holes.
Inferring black hole charge from backscattered electromagnetic radiation
Luís C. B. Crispino; Sam R. Dolan; Atsushi Higuchi; Ednilton S. de Oliveira
2014-09-16
We compute the scattering cross section of Reissner-Nordstr\\"om black holes for the case of an incident electromagnetic wave. We describe how scattering is affected by both the conversion of electromagnetic to gravitational radiation, and the parity-dependence of phase shifts induced by the black hole charge. The latter effect creates a helicity-reversed scattering amplitude that is non-zero in the backward direction. We show that from the character of the electromagnetic wave scattered in the backward direction it is possible, in principle, to infer if a static black hole is charged.
Back reaction on a Reissner-Nordstro''m black hole
Wang, Bobo; Huang, Chao-guang
2001-06-15
The perturbed (''dressed'') metric of the conformally invariant scalar field in a Reissner-Nordstroem (RN) black hole is given by solving the semiclassical Einstein and Maxwell equations according to York's back-reaction approach. Some properties of the ''dressed'' black hole are obtained, such as its ''dressed'' mass, the location of the event horizon, and its surface gravity. It will also be found that the hypersurfaces of r{sub +} and r{sub {minus}} which are the event and Cauchy horizons in the ''naked'' RN black hole, become spacelike in the perturbed geometry.
A Nonsingular Brans Wormhole: An Analogue to Naked Black Holes
Amrita Bhattacharya; Ramil Izmailov; Ettore Laserra; Kamal K. Nandi
2011-07-28
In a recent paper, we showed the Jordan frame vacuum Brans Class I solution provided a wormhole analogue to Horowitz-Ross naked black hole in the wormhole range -3/2naked black holes, as described by Horowitz and Ross, are spacetimes where the tidal forces attain their maxima above the black hole horizon. We show that in the non-singular Class II spacetime this maxima is attained above the throat and thus can be treated as a wormhole analogue. Some related issues are also addressed.
From Special Geometry to Black Hole Partition Functions
Thomas Mohaupt
2008-12-22
These notes are based on lectures given at the Erwin-Schrodinger Insitut in Vienna in 2006/07 and at the 2007 School on Attractor Mechanism in Frascati. Lecture I: special geometry from the superconformal point of view. Lecture II: black hole attractor mechanism, its underlying variational principle, and black hole partition functions. Lecture III: large and small BPS black holes in N=4 supergravity. Lecture IV: state counting for N=4 string compactifications. Appendix A: special geometry from the mathematical point of view. Appendix B: review of modular forms. Contains four problems which allow the readers to develop some of the key concepts by themselves.
Safeguards Approaches for Black Box Processes or Facilities
Diaz-Marcano, Helly; Gitau, Ernest TN; Hockert, John; Miller, Erin; Wylie, Joann
2013-09-25
The objective of this study is to determine whether a safeguards approach can be developed for “black box” processes or facilities. These are facilities where a State or operator may limit IAEA access to specific processes or portions of a facility; in other cases, the IAEA may be prohibited access to the entire facility. The determination of whether a black box process or facility is safeguardable is dependent upon the details of the process type, design, and layout; the specific limitations on inspector access; and the restrictions placed upon the design information that can be provided to the IAEA. This analysis identified the necessary conditions for safeguardability of black box processes and facilities.
Static Charged Black Hole Solutions in Horava-Lifshitz Gravity
Jin-Zhang Tang
2010-01-12
In the present work, we search static charged black hole solutions to Ho\\v{r}ava-Lifshitz gravity with or without projectability condition. We consider the most general form of action which electromagnetic field couples with Ho\\v{r}ava-Lifshitz gravity. With the projectability condition, we find dS-Reissner-Nordstrom black hole solution in Painlev\\'e-Gullstrand type coordinates in the IR region and a de-Sitter space-time solution in the UV region. Without the projectability condition, in the IR region, we find an especial static charged black hole solution.
The r-Process in Black Hole Winds
Shinya Wanajo; Hans-Thomas Janka
2010-06-11
All the current r-process scenarios relevant to core-collapse supernovae are facing severe difficulties. In particular, recent core-collapse simulations with neutrino transport show no sign of a neutron-rich wind from the proto-neutron star. In this paper, we discuss nucleosynthesis of the r-process in an alternative astrophysical site, "black hole winds", which are the neutrino-driven outflow from the accretion torus around a black hole. This condition is assumed to be realized in double neutron star mergers, neutron star - black hole mergers, or hypernovae.
Scalar emission in a rotating Gödel black hole
Songbai Chen; Bin Wang; Jiliang Jing
2008-08-23
We study the absorption probability and Hawking radiation of the scalar field in the rotating G\\"{o}del black hole in minimal five-dimensional gauged supergravity. We find that G\\"{o}del parameter $j$ imprints in the greybody factor and Hawking radiation. It plays a different role from the angular momentum of the black hole in the Hawking radiation and super-radiance. These information can help us know more about rotating G\\"{o}del black holes in minimal five-dimensional gauged supergravity.
Little Black Holes:Dark Matter And Ball Lightning
Mario Rabinowitz
2002-12-11
Small,quiescent black holes can be considered as candidates for the missing dark matter of the universe,and as the core energy source of ball lightning.By means of gravitational tunneling,directed radiation is emitted from black holes in a process much attenuated from that of Hawking radiation,P SH, which has proven elusive to detect.Gravitational tunneling emission is similar to electric field emission of electronsfrom a metal in that a second body is involved which lowers the barrier and gives the barrier a finite rather than infinite width.Hawking deals with a single isolated black hole.
Recent Progresses Of Accretion Disk Models Around Black Holes
Sandip K. Chakrabarti
1997-03-09
Accretion disk models have evolved from Bondi flows in the 1950s to Keplerian disks in the 1970s and finally to advective transonic flows in the 1990s. We discuss recent progresses in this subject and show that sub-Keplerian flows play a major role in determining the spectral properties of black holes. Centrifugal pressure supported enhanced density region outside the black hole horizon produces hard X-rays and gamma rays by reprocessing intercepted soft photons emitted by the Keplerian disk terminated farther out from the black holes. Quasi-periodic oscillations can also be understood from the dynamic or thermal resonance effects of the enhanced density region.
The Quantum Black Hole Specific Heat is Positive
Andrzej Z. Gorski; Pawel O. Mazur
1997-05-16
We suggest in this Letter that the Bekenstein-Hawking black hole entropy accounts for the degrees of freedom which are excited at low temperatures only and hence it leads to the negative specific heat. Taking into account the physical degrees of freedom which are excited at high temperatures, the existence of which we postulate, we compute the total specific heat of the quantum black hole that appears to be positive. This is done in analogy to the Planck's treatment of the black body radiation problem. Other thermodynamic functions are computed as well. Our results and the success of the thermodynamic description of the quantum black hole suggest an underlying atomic (discrete) structure of gravitation. The basic properties of these gravitational atoms are found.
Giant black hole ringings induced by massive gravity
Yves Decanini; Antoine Folacci; Mohamed Ould El Hadj
2014-01-01
A distorted black hole radiates gravitational waves in order to settle down in one of the geometries permitted by the no-hair theorem. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from the black hole quasinormal frequencies (which govern its oscillating behavior and its decay) and from the associated excitation factors (which determine intrinsically its amplitude) by carefully taking into account the source of the distortion. Here, by considering the Schwarzschild black hole in the framework of massive gravity, we show that the excitation factors have an unexpected strong resonant behavior leading to giant ringings which are, moreover, slowly decaying. Such extraordinary black hole ringings could be observed by the next generations of gravitational wave detectors and allow us to test the various massive gravity theories or their absence could be used to impose strong constraints on the graviton mass.
Black Holes in Gauss-Bonnet Gravity's Rainbow
Seyed Hossein Hendi; Mir Faizal
2015-08-08
In this paper, we will generalize the Gauss-Bonnet gravity to an energy dependent Gauss-Bonnet theory of gravity, which we shall call as the Gauss-Bonnet gravity's rainbow. We will also couple this theory to a Maxwell's theory. We will analyze black hole solutions in this energy dependent Gauss-Bonnet gravity's rainbow. We will calculate the modifications to the thermodynamics of black holes in the Gauss-Bonnet's gravity's rainbow. We will demonstrate that even though the thermodynamics of the black holes get modified in the Gauss-Bonnet gravity's rainbow, the first law of thermodynamics still holds for this modified thermodynamics. We will also comment on the thermal stability of the black hole solutions in this theory.
Black hole physics: recent developments and observational perspectives
Gourgoulhon, Eric
on a black hole: up to 42% of the mass-energy mc2 of accreted matter ! NB: thermonuclear reactions release: a very deep gravitational potential well Release of potential gravitational energy by accretion
Black holes and tests of gravitation Eric Gourgoulhon
Gourgoulhon, Eric
potential well Release of potential gravitational energy by accretion on a black hole: up to 42% of the mass-energy mc2 of accreted matter ! NB: thermonuclear reactions release less than 1% mc2 Matter falling
Black hole evaporation in a noncommutative charged Vaidya model
Sharif, M. Javed, W.
2012-06-15
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstroem-like solution of this model, which leads to an exact (t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Black-Body Radiation Of Noncommutative Gauge Fields
A. H. Fatollahi; M. Hajirahimi
2006-11-21
The black-body radiation is considered in a theory with noncommutative electromagnetic fields; that is noncommutativity is introduced in field space, rather than in real space. A direct implication of the result on Cosmic Microwave Background map is argued.
Ukraine's Military Role in the Black Sea Region
Coffman, Amy Beth; Crump, James Andrew; Dickson, Robbi K.; Mueller, Meaghan; Pulis, Sarah L.
2010-01-01
Only Ukraine's civilian and military leadership can determine the best course of action Ukraine should undertake to secure the Black Sea region (BSR). By analyzing Ukraine's precarious security environment and assessing the current security...
In Celebration of Black History Month, Energy Secretary Moniz...
Office of Environmental Management (EM)
Art of Science February 23, 2015 - 1:50am Addthis News Media Contact 202 586 4940 RSVP@hq.doe.gov In Celebration of Black History Month, Energy Secretary Moniz and Director of the...
MLK Day/Black History Month DOE Celebration
Broader source: Energy.gov [DOE]
Join us as the Department honors both Dr. King and Black History Month with a dialogue on the history of civil rights for all. Secretary Ernest Moniz will open our program.
Tensile Strength and the Mining of Black Holes
Adam R. Brown
2012-07-13
There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta and puts a severe constraint on the operation of 'space elevators' near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed and that as a consequence of this limitation the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.
Physiological responses of a black spruce forest to weather
1997-01-01
a black spruce forest to weather Michael L. Goulden, • Bruceresponses of the forest to weather. The annual rates ofgross forest CO 2 exchange to weather is required before the
Ecology of Wintering Black-capped Vireos in Mexico
Powell, Robert Andrew
2013-11-06
The black-capped vireo (Vireo atricapilla) is an endangered Neotropical migratory songbird that has received considerable attention in its breeding range, but relatively little attention in its winter range in Mexico. To ...
Circumnuclear Media and Accretion Rates of Quiescent Supermassive Black Holes
Generozov, Aleksey; Metzger, Brian D
2015-01-01
We calculate steady-state, one-dimensional hydrodynamic profiles of hot gas in slowly accreting ("quiescent") galactic nuclei for a range of central black hole masses, parameterized gas heating rates, and observationally-motivated stellar density profiles. Mass is supplied to the circumnuclear medium by stellar winds, while energy is injected primarily by stellar winds, supernovae, and black hole feedback. Analytic estimates are derived for the stagnation radius (where the radial velocity of the gas passes through zero) and the black hole accretion rate, as a function of the black hole mass and the gas heating efficiency, the latter being related to the star-formation history. We assess the conditions under which radiative instabilities develop in the hydrostatic region near the stagnation radius, both in the case of a single burst of star formation and for the average star formation history predicted by cosmological simulations. By combining a sample of measured nuclear X-ray luminosities from nearby quiesce...
Magnetic wormholes and black universes with invisible ghosts
Bronnikov, K A
2015-01-01
We construct explicit examples of globally regular static, spherically symmetric solutions in general relativity with scalar and electromagnetic fields describing traversable wormholes with flat and AdS asymptotics and regular black holes, in particular, black universes. (A black universe is a regular black hole with an expanding, asymptotically isotropic space-time beyond the horizon.) The existence of such objects requires invoking scalars with negative kinetic energy ("phantoms", or "ghosts"), which are not observed under usual physical conditions. To account for that, the so-called "trapped ghosts" were previously introduced, i.e., scalars whose kinetic energy is only negative in a restricted strong-field region of space-time and positive outside it. This approach leads to certain problems, including instability (as is illustrated here by derivation of an effective potential for spherical pertubations of such systems). In this paper, we use for model construction what we call "invisible ghosts", i.e., pha...
Improvements to the construction of binary black hole initial data
Serguei Ossokine; Francois Foucart; Harald P. Pfeiffer; Michael Boyle; Béla Szilágyi
2015-06-04
Construction of binary black hole initial data is a prerequisite for numerical evolutions of binary black holes. This paper reports improvements to the binary black hole initial data solver in the Spectral Einstein Code, to allow robust construction of initial data for mass-ratio above 10:1, and for dimensionless black hole spins above 0.9, while improving efficiency for lower mass-ratios and spins. We implement a more flexible domain decomposition, adaptive mesh refinement and an updated method for choosing free parameters. We also introduce a new method to control and eliminate residual linear momentum in initial data for precessing systems, and demonstrate that it eliminates gravitational mode mixing during the evolution. Finally, the new code is applied to construct initial data for hyperbolic scattering and for binaries with very small separation.
Black Image in Cinema and Theatre in America
Williams, Grayling
1983-01-01
BLACK IMAGE IN CINEMA AND THEATRE IN AMERICA* By GraylingIN THE AFRICAN-AMERICAN CINEMA Given the lack of informationa Negro's Ambition (1916). The cinema therefore provided the
The Energy for 2+1 Dimensional Black Hole Solutions
I-Ching Yang; Irina Radinschi
2006-11-05
The energy distributions of four 2+1 dimensional black hole solutions were obtained by using the Einstein and M{\\o}ller energy-momentum complexes. while $r \\to \\infty$, the energy distributions of these four solutions become divergence.
Quantum Emission from Two-Dimensional Black Holes
Steven B. Giddings; W. M. Nelson
2009-11-27
We investigate Hawking radiation from two-dimensional dilatonic black holes using standard quantization techniques. In the background of a collapsing black hole solution the Bogoliubov coefficients can be exactly determined. In the regime after the black hole has settled down to an `equilibrium' state but before the backreaction becomes important these give the known result of a thermal distribution of Hawking radiation at temperature lambda/(2pi). The density matrix is computed in this regime and shown to be purely thermal. Similar techniques can be used to derive the stress tensor. The resulting expression agrees with the derivation based on the conformal anomaly and can be used to incorporate the backreaction. Corrections to the thermal density matrix are also examined, and it is argued that to leading order in perturbation theory the effect of the backreaction is to modify the Bogoliubov transformation, but not in a way that restores information lost to the black holes.
An Energy Extremum Principle for Charged Black Holes
Fraser, Scott
2015-01-01
For a set of asymptotically flat black holes with arbitrary charges and masses, all initially at rest and well-separated, we prove the following extremum principle: the extremal charge configuration ($|q_i|=m_i$ for each black hole) can be derived by extremizing the total energy, for variations of the black hole apparent horizon areas, at fixed charges and fixed Euclidean separations. If all charges have the same sign, this result is a variational principle that reinterprets the static equilibrium of the Majumdar-Papapetrou-Hartle-Hawking solution as an extremum of total energy, rather than as a balance of forces; this result augments a list of related variational principles for static black holes, and is consistent with the independently known BPS energy minimum.
An Energy Extremum Principle for Charged Black Holes
Scott Fraser; Shaker Von Price Funkhouser
2015-09-13
For a set of asymptotically flat black holes with arbitrary charges and masses, all initially at rest and well-separated, we prove the following extremum principle: the extremal charge configuration ($|q_i|=m_i$ for each black hole) can be derived by extremizing the total energy, for variations of the black hole apparent horizon areas, at fixed charges and fixed Euclidean separations. If all charges have the same sign, this result is a variational principle that reinterprets the static equilibrium of the Majumdar-Papapetrou-Hartle-Hawking solution as an extremum of total energy, rather than as a balance of forces; this result augments a list of related variational principles for static black holes, and is consistent with the independently known BPS energy minimum.
Energy Distribution of a Stringy Charged Black Hole
Ragab M. Gad
2003-06-22
The energy distribution associated with a stringy charged black hole is studied using M{\\o}ller's energy-momentum complex. Our result is reasonable and it differs from that known in literature using Einstein's energy-momentum complex.
Larger Black Flour Beetle in Southern High Plains Homes
Porter, Patrick; McIntyre, Nancy E.
2007-04-09
Larger black flour beetles have invaded homes and other buildings in some Southern High Plains counties in Texas. This publication explains how to identify the beetles, find and eliminate the source, and exclude the insects from the house....
Black hole remnant in asymptotic Anti-de Sitter space
Wen, Wen-Yu
2015-01-01
It is known that a solution of remnant were suggested for black hole ground state after surface gravity is corrected by loop quantum effect. On the other hand, a Schwarzschild black hole in asymptotic Anti-de Sitter space would tunnel into the thermal soliton solution known as the Hawking-Page phase transition. In this letter, we investigate the low temperature phase of three-dimensional BTZ black hole and four-dimensional AdS Schwarzschild black hole. We find that the thermal soliton is energetically favored than the remnant solution at low temperature in three dimensions, while Planck-size remnant is still possible in four dimensions. Though the BTZ remnant seems energetically disfavored, we argue that it is still possible to be found in the overcooled phase if strings were present and its implication is discussed.
Spectral Properties of Galactic and Extragalactic Black Hole Candidates
Sandip K. Chakrabarti
1996-11-10
We review current theoretical understanding of the spectral properties (low and high states, transition of states, quasi-periodic oscillations etc.) of the low mass as well as supermassive black hole candidates.
Hooperchicks: Black Women, College Basketball and Identity Negotiation
Clay, Charity
2014-08-14
This project used in depth interviews with Black women who played Division I college basketball from1997-2007 to elucidate how they developed their racial, gender and athletic identities during adolescence, and how those ...
Energy Department Announces New Technical Review to Assess Black...
being designed and built to treat millions of gallons of tank waste from plutonium production at Hanford from the 1940s to the 1980s. The equipment in the facility's 18 black...
Black Hole Demographics from the M(BH)-sigma Relation
David Merritt; Laura Ferrarese
2001-03-03
We analyze a sample of 32 galaxies for which a dynamical estimate of the mass of the hot stellar component, M_bulge, is available. For each of these galaxies, we calculate the mass of the central black hole, M_BH, using the tight empirical correlation between M_BH and the bulge stellar velocity dispersion. The frequency function N(log M_BH/M_bulge) is reasonably well described as a Gaussian with ~ -2.90 and standard deviation 0.45; the implied mean ratio of black hole to bulge mass is a factor 5 smaller than generally quoted in the literature. We present marginal evidence for a lower, average black-hole mass fraction in more massive galaxies. The total mass density in black holes in the local Universe is estimated to be 5 x 10^5 solar masses per cubic megaparsec, consistent with that inferred from high redshift (z ~ 2) AGNs.
Electromagnetic quasinormal modes of D-dimensional black holes
A. López-Ortega
2006-11-02
Using the monodromy method we calculate the asymptotic quasinormal (QN) frequencies of an electromagnetic field moving in D-dimensional Schwarzschild and Schwarzschild de Sitter (SdS) black holes ($D\\geq 4$). For the D-dimensional Schwarzschild anti-de Sitter (SadS) black hole we also compute these frequencies with a similar method. Moreover, we calculate the electromagnetic normal modes of the D-dimensional anti-de Sitter (AdS) spacetime.
Linear waves in the interior of extremal black holes I
Gajic, Dejan
2015-01-01
We consider solutions to the linear wave equation in the interior region of extremal Reissner-Nordstr\\"om black holes. We show that, under suitable assumptions on the initial data, the solutions can be extended continuously beyond the Cauchy horizon and moreover, that their local energy is finite. This result is in contrast with previously established results for subextremal Reissner-Nordstr\\"om black holes, where the local energy was shown to generically blow up at the Cauchy horizon.
Black Hole Statistical Mechanics and The Angular Velocity Ensemble
Mitchell Thomson; Charles C. Dyer
2012-03-29
An new ensemble - the angular velocity ensemble - is derived using Jaynes' method of maximising entropy subject to prior information constraints. The relevance of the ensemble to black holes is motivated by a discussion of external parameters in statistical mechanics and their absence from the Hamiltonian of general relativity. It is shown how this leads to difficulty in deriving entropy as a function of state and recovering the first law of thermodynamics from the microcanonical and canonical ensembles applied to black holes.
Spectral Properties of Black Holes in Gamma Rays
Sandip K. Chakrabarti
2005-01-14
Black holes are the most compact objects in the universe. Therefore, matter accreting onto is likely to radiate photons of energy comparable to very high gravitational potential energy. We discuss the nature of the emitted radiation in X-rays and gamma-rays from black hole candidates. We present theoretical solutions which comprise both Keplerian and sub-Keplerian components and suggest that shocks in accretion and outflows
Bounding the greybody factors for Schwarzschild black holes
Boonserm, Petarpa
2008-01-01
Greybody factors in black hole physics modify the naive Planckian spectrum that is predicted for Hawking radiation when working in the limit of geometrical optics. We consider the Schwarzschild geometry in (3+1) dimensions, and analyze the Regge-Wheeler equation for arbitrary particle spin S and wave-mode angular momentum L, deriving rigourous bounds on the greybody factors as a function of S, L, wave frequency (omega), and the black hole mass, m.
Masses of Stellar Black Holes and Testing Theories of Gravitation
K. A. Postnov; A. M. Cherepashchuk
2004-01-22
We analyze the mass distribution of stellar black holes derived from the light and radial velocity curves of optical stars in close binary systems using dynamical methods. The systematic errors inherent in this approach are discussed. These are associated primarily with uncertainties in models for the contribution from gaseous structures to the optical brightness of the systems under consideration. The mass distribution is nearly flat in the range 4-15M_sun. This is compared with the mass distribution for black holes in massive close binaries, which can be manifest as ultraluminous X-ray sources (L_x > 10^39 erg/s) observed in other galaxies. If the X-ray luminosities of these objects correspond to the Eddington limit, the black-hole mass distribution should be described by a power law, which is incompatible with the flat shape derived dynamically from observations of close binaries in our Galaxy. One possible explanation of this discrepancy is the rapid evaporation of stellar-mass black holes predicted in recent multi-dimensional models of gravity. This hypothesis can be verifed by measuring the stellar black-hole mass spectrum or finding isolated or binary black holes with masses below 3M_sun.
Energy spectrum of black holes : a new view
Abhishek Majhi
2015-12-22
Energy of a black hole is usually quantized by invoking some area quantization scheme after expressing the energy in terms of the horizon area. However, in this approach one has to quantize the local and asymptotic energy of the black hole separately and the two results do not manifest any physical correspondence with each other. Here, as opposed to this practice, we find the unique energy spectrum of black holes by adopting a top-down approach. The physical links among the underlying quantum theory, statistical mechanics and thermodynamics of the black hole horizon play the central role in determining the energy spectrum. The energy spectrum that we obtain, explicitly reveals the correspondence between asymptotic and local observations through the presence of the surface gravity of the horizon as a parameter in the spectrum, rather than being expressed as a function of area and consequently getting quantized in the usual approach. Thus, our result presents a new view as far as black hole energy quantization is concerned. The calculations are performed using the quantum geometric description of black hole horizons as laid down by loop quantum gravity.
Spin alignment and differential accretion in merging black hole binaries
Davide Gerosa; Benedetta Veronesi; Giuseppe Lodato; Giovanni Rosotti
2015-07-01
Interactions between a supermassive black hole binary and the surrounding accretion disc can both assist the binary inspiral and align the black hole spins to the disc angular momentum. While binary migration is due to angular-momentum transfer within the circumbinary disc, the spin-alignment process is driven by the mass accreting on to each black hole. Mass transfer between different disc components thus couples the inspiral and the alignment process together. Mass is expected to leak through the cavity cleared by the binary, and preferentially accretes on to the lighter (secondary) black hole which orbits closer to the disc edge. Low accretion rate on to the heavier (primary) black hole slows the alignment process down. We revisit the problem and develop a semi-analytical model to describe the coupling between gas-driven inspiral and spin alignment, finding that binaries with mass ratio qprimaries from aligning. Binary black holes with misaligned primaries are ideal candidates for precession effects in the strong-gravity regime and may suffer from moderately large (~1500 km/s) recoil velocities.
Relating Follicly-Challenged Compact Stars to Bald Black Holes
Kent Yagi; Nicolas Yunes
2015-07-08
Compact stars satisfy certain no-hair relations through which their multipole moments are given by their mass, spin and quadrupole moment. These relations are approximately independent of their equation of state, relating pressure to density. Such relations are similar to the black hole no-hair theorems, but these possess event horizons inside which information that led to their formation can hide. Compact stars do not possess horizons, so whether their no-hair relations are related to the black hole ones is unclear. We investigate how the two relations are related by studying relations among multipole moments for compact stars with anisotropic pressure as a toy model, which allows such stars to be more compact than those with isotropic pressure. We here show numerically that the compact star no-hair relations approach the black hole ones as the compactness approaches that of a black hole. We also prove analytically that the current dipole moment exactly reaches the black hole limit quadratically in compactness as strongly-anisotropic stars approach the black hole limit. We moreover show that compact stars become progressively oblate in this limit, even if prolate at low compactness due to strong anisotropies.
Nonlinearly charged Lifshitz black holes for any exponent $z>1$
Abigail Alvarez; Eloy Ayón-Beato; Hernán A. González; Mokhtar Hassaïne
2015-01-27
Charged Lifshitz black holes for the Einstein-Proca-Maxwell system with a negative cosmological constant in arbitrary dimension $D$ are known only if the dynamical critical exponent is fixed as $z=2(D-2)$. In the present work, we show that these configurations can be extended to much more general charged black holes which in addition exist for any value of the dynamical exponent $z>1$ by considering a nonlinear electrodynamics instead of the Maxwell theory. More precisely, we introduce a two-parametric nonlinear electrodynamics defined in the more general, but less known, so-called $(\\mathcal{H},P)$-formalism and obtain a family of charged black hole solutions depending on two parameters. We also remark that the value of the dynamical exponent $z=D-2$ turns out to be critical in the sense that it yields asymptotically Lifshitz black holes with logarithmic decay supported by a particular logarithmic electrodynamics. All these configurations include extremal Lifshitz black holes. Charged topological Lifshitz black holes are also shown to emerge by slightly generalizing the proposed electrodynamics.
Stability of black holes based on horizon thermodynamics
Ma, Meng-Sen
2015-01-01
On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss-Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables $E,P,V,T,S$. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, $P=P(V,T)$. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that $P>0$ is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss-Bonnet gravity negative pressure can be feasible, but only local stab...
Bright vigorous winds as signposts of supermassive black hole birth
Fiacconi, Davide
2015-01-01
The formation of supermassive black holes is still an outstanding question. In the quasi-star scenario, black hole seeds experience an initial super-Eddington growth, that in less than a million years may leave a $10^4-10^5$ M$_{\\odot}$ black hole at the centre of a protogalaxy at $z \\sim 20-10$. Super-Eddington accretion, however, may be accompanied by vigorous mass loss that can limit the amount of mass that reaches the black hole. In this paper, we critically assess the impact of radiative driven winds, launched from the surface of the massive envelopes from which the black hole accretes. Solving the full wind equations coupled with the hydrostatic structure of the envelope, we find mass outflows with rates between a few tens and $10^4$ M$_{\\odot}$ yr$^{-1}$, mainly powered by advection luminosity within the outflow. We therefore confirm the claim by Dotan, Rossi & Shaviv (2011) that mass losses can severely affect the black hole seed early growth within a quasi-star. In particular, seeds with mass $>1...
The mass function of high redshift seed black holes
Giuseppe Lodato; Priyamvada Natarajan
2007-02-13
In this paper we derive the mass function of seed black holes that result from the central mass concentrated via disc accretion in collapsed haloes at redshift $z\\approx 15$. Using standard arguments including stability, we show that these pre-galactic discs can assemble a significant mass concentration in the inner regions, providing fuel for the formation and initial growth of super-massive black holes. Assuming that these mass concentrations do result in central seed black holes, we determine the mass distribution of these seeds as a function of key halo properties. The seed mass distribution determined here turns out to be asymmetric and skewed to higher masses. Starting with these initial seeds, building up to $10^9$ solar masses by $z = 6$ to power the bright quasars is not a problem in the standard LCDM cosmogony. These seed black holes in gas rich environments are likely to grow into the supermassive black holes at later times via mergers and accretion. Gas accretion onto these seeds at high redshift will produce miniquasars that likely play an important role in the reionization of the Universe. Some of these seed black holes on the other hand could be wandering in galaxy haloes as a consequence of frequent mergers, powering the off-nuclear ultra-luminous X-ray sources detected in nearby galaxies.
McDowell, Jacqueline
2009-05-15
Framed as an instrumental case study, the purpose of this investigation was to understand how a select group of women, Black female athletic directors, define and negotiate their race, gender, and class identities. Data ...
I am Black AND Jewish: Black Jewish Women’s Experiences in “White” Jewish Communities in Brazil
Gondek, Abby S.
2008-01-01
the contemporary black movement in Brazil. In R. Reichmann (Race in contemporary Brazil (pp. 155-166). University Park,J.J. Crocitti (Eds. ), The Brazil reader: History, culture,
Wilson, Misty Michelle
2009-05-15
While a great deal of sociological and psychological research has been done on black-white interracial couples and the challenges they have faced in past eras, the communication between the partners remains largely ...
Black holes in young stellar clusters
Goswami, Sanghamitra; Kiel, Paul; Rasio, Frederic A. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)
2014-02-01
We present theoretical models for stellar black hole (BH) properties in young, massive star clusters. Using a Monte Carlo code for stellar dynamics, we model realistic star clusters with N ? 5 × 10{sup 5} stars and significant binary fractions (up to 50%) with self-consistent treatments of stellar dynamics and stellar evolution. We compute the formation rates and characteristic properties of single and binary BHs for various representative ages, cluster parameters, and metallicities. Because of dynamical interactions and supernova (SN) kicks, more single BHs end up retained in clusters compared to BHs in binaries. We also find that the ejection of BHs from a cluster is a strong function of initial density. In low-density clusters (where dynamical effects are negligible), it is mainly SN kicks that eject BHs from the cluster, whereas in high-density clusters (initial central density ? {sub c}(0) ? 10{sup 5} M {sub ?} pc{sup –3} in our models) the BH ejection rate is enhanced significantly by dynamics. Dynamical interactions of binary systems in dense clusters also modify the orbital period and eccentricity distributions while increasing the probability of a BH having a more massive companion.
Black Hole Spectral States and Physical Connections
John A. Tomsick
2005-09-06
The dramatic changes seen in the X-ray spectral and timing properties of accreting black hole candidates (BHCs) provide important clues about the accretion and jet formation processes that occur in these systems. Dividing the different source behaviors into spectral states provides a framework for studying BHCs. To date, there have been three main classification schemes with Luminosity-based, Component-based, or Transition-based criteria. The canonical, Luminosity-based criteria and physical models that are based on this concept do not provide clear explanations for several phenomena, including hysteresis of spectral states and the presence of jets. I discuss the re-definitions of states, focusing on an application of the Component-based states to more than 400 RXTE observations of the recurrent BHC 4U 1630-47. We compare the X-ray properties for the recent 2002-2004 outburst to those of an earlier (1998) outburst, during which radio jets were observed. The results suggest a connection between hysteresis of states and major jet ejections, and it is possible that both of these are related to the evolution of the inner radius of the optically thick accretion disk.
Galaxies nurtured by mature black holes
Morikawa, Masahiro
2015-01-01
Supermassive black holes (SMBH) of size $10^{6-10}M_{\\odot}$ are common in the Universe and they define the center of the galaxies. A galaxy and the SMBH are generally thought to have co-evolved. However, the SMBH cannot evolve so fast as commonly observed even at redshift $z>6$. Therefore, we explore a natural hypothesis that the SMBH has been already formed mature at $z\\gtrapprox10$ before stars and galaxies. The SMBH forms energetic jets and outflows which trigger massive star formation in the ambient gas. They eventually construct globular clusters and classical bulge as well as the body of elliptical galaxies. We propose simple models which implement these processes. We point out that the globular clusters and classical bulges have a common origin but are in different phases. The same is true for the elliptical and spiral galaxies. Physics behind these phase division is the runaway star formation process with strong feedback to SMBH. This is similar to the forest-fire model that displays self-organized c...
Thermodynamics of Black Hole Horizons and Kerr/CFT Correspondence
Bin Chen; Shen-xiu Liu; Jia-ju Zhang
2012-11-02
In this paper we investigate the thermodynamics of the inner horizon and its implication on the holographic description of the black hole. We focus on the black holes with two physical horizons. Under reasonable assumption, we prove that the first law of thermodynamics of the outer horizon always indicates that of the inner horizon. As a result, the fact that the area product being mass-independent is equivalent to the relation $T_+S_+=T_-S_-$, with $T_\\pm$ and $S_\\pm$ being the Hawking temperatures and the entropies of the outer and inner horizon respectively. We find that the mass-independence of area product breaks down in general Myers-Perry black holes with spacetime dimension $d\\geq6$ and Kerr-AdS black holes with $d\\geq4$. Moreover we discuss the implication of the first laws of the outer and inner horizons on the thermodynamics of the right- and left-moving sectors of dual CFT in Kerr/CFT correspondence. We show that once the relation $T_+S_+=T_-S_-$ is satisfied, the central charges of two sectors must be same. Furthermore from the thermodynamics relations, we read the dimensionless temperatures of microscopic CFT, which are in exact agreement with the ones obtained from hidden conformal symmetry in the low frequency scattering off the black holes, and then determine the central charges. This method works well in well-known cases in Kerr/CFT correspondence, and reproduce successfully the holographic pictures for 4D Kerr-Newman and 5D Kerr black holes. We go on to predict the central charges and temperatures of a possible holographic CFT description dual to 5D doubly rotating black ring.
Constraining Black Hole Spin Via X-ray Spectroscopy
Laura W. Brenneman; Christopher S. Reynolds
2006-08-23
We present an analysis of the observed broad iron line feature and putative warm absorber in the long 2001 XMM-Newton observation of the Seyfert-1.2 galaxy MCG-6-30-15. The new "kerrdisk" model we have designed for simulating line emission from accretion disk systems allows black hole spin to be a free parameter in the fit, enabling the user to formally constrain the angular momentum of a black hole, among other physical parameters of the system. In an important extension of previous work, we derive constraints on the black hole spin in MCG-6-30-15 using a self-consistent model for X-ray reflection from the surface of the accretion disk while simultaneously accounting for absorption by dusty photoionized material along the line of sight (the warm absorber). Even including these complications, the XMM-Newton/EPIC-pn data require extreme relativistic broadening of the X-ray reflection spectrum; assuming no emission from within the radius of marginal stability, we derive a formal constraint on the dimensionless black hole spin parameter of a > 0.987 at 90% confidence. The principal unmodeled effect that can significantly reduce the inferred black hole spin is powerful emission from within the radius of marginal stability. Although significant theoretical developments are required to fully understand this region, we argue that the need for a rapidly spinning black hole is robust to physically plausible levels of emission from within the radius of marginal stability. In particular, we show that a non-rotating black hole is strongly ruled out.
Preparedfor theTAPPIInternationalChemicalRecoveryConference .Tampa, Florida, 1-4June1998
replacement of Tomlinson boiler/steam turbine systems with black liquor gasifier/combined cycle (BLGCC by expected liquor throughput: the Tomlinson boiler is sized accordingly, and the steam turbine is sized of a specific gas turbine. There are many different models from which to choose, but with only a fixed set
Mo, Jie-Xiong
2014-01-01
To provide an analytic verification of the nature of phase transition at the critical point of $P-V$ criticality, the original expressions of Ehrenfest equations have been introduced directly. By treating the cosmological constant and its conjugate quantity as thermodynamic pressure and volume respectively, we carry out analytical check of classical Ehrenfest equations. To show that our approach is universal, we investigate not only higher-dimensional charged AdS black holes, but also rotating AdS black holes. Not only are the examples of Einstein gravity shown, but also the example of modified gravity is presented for Gauss-Bonnet AdS black holes. The specific heat at constant pressure $C_P$, the volume expansion coefficient $\\alpha$ and the isothermal compressibility coefficient $\\kappa_T$ are found to diverge exactly at the critical point. It has been verified that both Ehrenfest equations hold at the critical point of $P-V$ criticality in the extended phase spaces of AdS black holes. So the nature of the ...
Thermodynamics of Three-dimensional Black Holes via Charged Particle Absorption
Gwak, Bogeun
2015-01-01
We have shown that changes occur in a (2+1)-dimensional charged black hole by adding a charged probe. The particle increases the entropy of the black hole and guarantees the second law of thermodynamics. The first law of thermodynamics is derived from the change in the black hole mass. Using the particle absorption, we test the extremal black hole and find out that the mass of the extremal black hole increases more than the electric charge. Therefore, the outer horizon of the black hole still exists. However, the extremal condition becomes non-extremal.
Can reducing black carbon emissions counteract global warming?
Tami C. Bond; Haolin Sun
2005-08-15
Field measurements and model results have recently shown that aerosols may have important climatic impacts. One line of inquiry has investigated whether reducing climate-warming soot or black carbon aerosol emissions can form a viable component of mitigating global warming. Black carbon is produced by poor combustion, from our example hard coal cooking fires for and industrial pulverized coal boilers. The authors review and acknowledge scientific arguments against considering aerosols and greenhouse gases in a common framework, including the differences in the physical mechanisms of climate change and relevant time scales. It is argued that such a joint consideration is consistent with the language of the United Nations Framework Convention on Climate Change. Results from published climate-modeling studies are synthesized to obtain a global warming potential for black carbon relative to that of CO{sub 2} (680 on a 100 year basis). This calculation enables a discussion of cost-effectiveness for mitigating the largest sources of black carbon. It is found that many emission reductions are either expensive or difficult to enact when compared with greenhouse gases, particularly in Annex I countries. Finally, a role for black carbon in climate mitigation strategies is proposed that is consistent with the apparently conflicting arguments raised during the discussion. Addressing these emissions is a promising way to reduce climatic interference primarily for nations that have not yet agreed to address greenhouse gas emissions and provides the potential for a parallel climate agreement. 31 refs., 3 figs., 1 tab.
Topological black holes in Lovelock-Born-Infeld gravity
Dehghani, M. H.; Alinejadi, N.; Hendi, S. H.
2008-05-15
In this paper, we present topological black holes of third order Lovelock gravity in the presence of cosmological constant and nonlinear electromagnetic Born-Infeld field. Depending on the metric parameters, these solutions may be interpreted as black hole solutions with inner and outer event horizons, an extreme black hole or naked singularity. We investigate the thermodynamics of asymptotically flat solutions and show that the thermodynamic and conserved quantities of these black holes satisfy the first law of thermodynamic. We also endow the Ricci flat solutions with a global rotation and calculate the finite action and conserved quantities of these class of solutions by using the counterterm method. We compute the entropy through the use of the Gibbs-Duhem relation and find that the entropy obeys the area law. We obtain a Smarr-type formula for the mass as a function of the entropy, the angular momenta, and the charge, and compute temperature, angular velocities, and electric potential and show that these thermodynamic quantities coincide with their values which are computed through the use of geometry. Finally, we perform a stability analysis for this class of solutions in both the canonical and the grand-canonical ensemble and show that the presence of a nonlinear electromagnetic field and higher curvature terms has no effect on the stability of the black branes, and they are stable in the whole phase space.
Semi-classical approach to quantum black holes
Euro Spallucci; Anais Smailagic
2014-10-07
In this Chapter we would like to review a "~phenomenological~" approach taking into account the most fundamental feature of string theory or, more in general, of quantum gravity, whatever its origin, which is the existence of a minimal length in the space-time fabric. This length is generally identified with the Planck length, or the string length, but it could be also much longer down to the TeV region. A simple and effective way to keep track of the effects the minimal length in black hole geometries is to solve the Einstein equations with an energy momentum tensor describing non point-like matter. The immediate consequence is the absence of any curvature singularity. Where textbook solutions of the Einstein equations loose any physical meaning because of infinite tidal forces, we find a de Sitter vacuum core of high, but finite, energy density and pressure. An additional improvement regards the final stage of the black hole evaporation leading to a vanishing Hawking temperature even in the neutral, non-rotating, case. In spite of th simplicity of this model we are able to describe the final stage of the black hole evaporation, resulting in a cold remnant with a degenerate, extremal, horizon of radius of the order of the minimal length. In this chapter we shall describe only neutral, spherically symmetric, regular black holes although charged, rotating and higher dimensional black holes can be found in the literature.
On geodesic dynamics in deformed black-hole fields
Old?ich Semerák; Petra Suková
2015-09-28
"Almost all" seems to be known about isolated stationary black holes in asymptotically flat space-times and about the behaviour of {\\em test} matter and fields in their backgrounds. The black holes likely present in galactic nuclei and in some X-ray binaries are commonly being represented by the Kerr metric, but actually they are not isolated (they are detected only thanks to a strong interaction with the surroundings), they are not stationary (black-hole sources are rather strongly variable) and they also probably do not live in an asymptotically flat universe. Such "perturbations" may query the classical black-hole theorems (how robust are the latter against them?) and certainly affect particles and fields around, which can have observational consequences. In the present contribution we examine how the geodesic structure of the static and axially symmetric black-hole space-time responds to the presence of an additional matter in the form of a thin disc or ring. We use several different methods to show that geodesic motion may become chaotic, to reveal the strength and type of this irregularity and its dependence on parameters. The relevance of such an analysis for galactic nuclei is briefly commented on.
Black hole spectroscopy from Loop Quantum Gravity models
Aurelien Barrau; Xiangyu Cao; Karim Noui; Alejandro Perez
2015-04-21
Using Monte Carlo simulations, we compute the integrated emission spectra of black holes in the framework of Loop Quantum Gravity (LQG). The black hole emission rates are governed by the entropy whose value, in recent holographic loop quantum gravity models, was shown to agree at leading order with the Bekenstein-Hawking entropy. Quantum corrections depend on the Barbero-Immirzi parameter $\\gamma$. Starting with black holes of initial horizon area $A \\sim 10^2$ in Planck units, we present the spectra for different values of $\\gamma$. Each spectrum clearly decomposes in two distinct parts: a continuous background which corresponds to the semi-classical stages of the evaporation and a series of discrete peaks which constitutes a signature of the deep quantum structure of the black hole. We show that $\\gamma$ has an effect on both parts that we analyze in details. Finally, we estimate the number of black holes and the instrumental resolution required to experimentally distinguish between the considered models.
Mass and Free Energy of Lovelock Black Holes
David Kastor; Sourya Ray; Jennie Traschen
2011-06-20
An explicit formula for the ADM mass of an asymptotically AdS black hole in a generic Lovelock gravity theory is presented, identical in form to that in Einstein gravity, but multiplied by a function of the Lovelock coupling constants and the AdS curvature radius. A Gauss' law type formula relates the mass, which is an integral at infinity, to an expression depending instead on the horizon radius. This and other thermodynamic quantities, such as the free energy, are then analyzed in the limits of small and large horizon radius, yielding results that are independent of the detailed choice of Lovelock couplings. In even dimensions, the temperature diverges in both limits, implying the existence of a minimum temperature for black holes. The negative free energy of sufficiently large black holes implies the existence of a Hawking-Page transition. In odd dimensions the temperature still diverges for large black holes, which again have negative free energy. However, the temperature vanishes as the horizon radius tends to zero and sufficiently small black holes have positive specific heat.
Dissipative accretion flows around a rotating black hole
Santabrata Das; Sandip K. Chakrabarti
2008-06-12
We study the dynamical structure of a cooling dominated rotating accretion flow around a spinning black hole. We show that non-linear phenomena such as shock waves can be studied in terms of only three flow parameters, namely, the specific energy (${\\cal E}$), the specific angular momentum ($\\lambda$) and the accretion rate (${\\dot m}$) of the flow. We present all possible accretion solutions. We find that a significant region of the parameter space in the ${\\cal E}-\\lambda$ plane allows global accretion shock solutions. The effective area of the parameter space for which the Rankine-Hugoniot shocks are possible is maximum when the flow is dissipation free. It decreases with the increase of cooling effects and finally disappears when the cooling is high enough. We show that shock forms further away when the black hole is rotating compared to the solution around a Schwarzschild black hole with identical flow parameters at a large distance. However, in a normalized sense, the flow parameters for which the shocks form around the rotating black holes are produced shocks closer to the hole. The location of the shock is also dictated by the cooling efficiency in that higher the accretion rate (${\\dot m}$), the closer is the shock location. We believe that some of the high frequency quasi-periodic oscillations may be due to the flows with higher accretion rate around the rotating black holes.
Colliding Axion-Dilaton Plane Waves from Black Holes
Patricia Schwarz
1997-08-01
The colliding plane wave metric discovered by Ferrari and Iba\\~{n}ez to be locally isometric to the interior of a Schwarzschild black hole is extended to the case of general axion-dilaton black holes. Because the transformation maps either black hole horizon to the focal plane of the colliding waves, this entire class of colliding plane wave spacetimes only suffers from the formation of spacetime singularities in the limits where the inner horizon itself is singular, which occur in the Schwarzschild and dilaton black hole limits. The supersymmetric limit corresponding to the extreme axion-dilaton black hole yields the Bertotti-Robinson metric with the axion and dilaton fields flowing to fixed constant values. The maximal analytic extension of this metric across the Cauchy horizon yields a spacetime in which two sandwich waves in a cylindrical universe collide to produce a semi-infinite chain of Reissner-Nordstrom-like wormholes. The focussing of particle and string geodesics in this spacetime is explored.
The mass function of high redshift seed black holes
Lodato, G; Lodato, Giuseppe; Natarajan, Priyamvada
2007-01-01
In this paper we derive the mass function of seed black holes that result from the central mass concentrated via disc accretion in collapsed haloes at redshift $z\\approx 15$. Using standard arguments including stability, we show that these pre-galactic discs can assemble a significant mass concentration in the inner regions, providing fuel for the formation and initial growth of super-massive black holes. Assuming that these mass concentrations do result in central seed black holes, we determine the mass distribution of these seeds as a function of key halo properties. The seed mass distribution determined here turns out to be asymmetric and skewed to higher masses. Starting with these initial seeds, building up to $10^9$ solar masses by $z = 6$ to power the bright quasars is not a problem in the standard LCDM cosmogony. These seed black holes in gas rich environments are likely to grow into the supermassive black holes at later times via mergers and accretion. Gas accretion onto these seeds at high redshift ...
Distorted black holes from a vacuum 5-d spherical solution
Capistrano, Abraão J S; Ulhoa, Sergio C; Amorim, Ronni G G
2015-01-01
We study the deformation caused by the influence of extrinsic curvature on a vacuum spherically symmetric metric embedded in a 5-d bulk. In this sense, we investigate the produced stationary black-holes and derive general properties such as its mass and horizons. As an application, a test moving particle near such black-holes is also shown as well the distortion caused by extrinsic curvature on its movement. Accordingly, using asymptotically conformal flat condition on the extrinsic curvature and an analytical expansion of a set of \\emph{n}-scalar fields, we show that the resulting black holes must be large and constrained in the range $-1/2 \\leq n \\leq 1.8$ that are locally thermodynamically stable, but not globally preferred.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett
2015-07-15
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Exploring Higher Dimensional Black Holes at the Large Hadron Collider
C. M. Harris; M. J. Palmer; M. A. Parker; P. Richardson; A. Sabetfakhri; B. R. Webber
2004-11-01
In some extra dimension theories with a TeV fundamental Planck scale, black holes could be produced in future collider experiments. Although cross sections can be large, measuring the model parameters is difficult due to the many theoretical uncertainties. Here we discuss those uncertainties and then we study the experimental characteristics of black hole production and decay at a typical detector using the ATLAS detector as a guide. We present a new technique for measuring the temperature of black holes that applies to many models. We apply this technique to a test case with four extra dimensions and, using an estimate of the parton-level production cross section error of 20%, determine the Planck mass to 15% and the number of extra dimensions to +-0.75.
Holographic Superconductors with Ho?ava-Lifshitz Black Holes
Rong-Gen Cai; Hai-Qing Zhang
2009-12-03
We discuss the phase transition of planar black holes in Ho\\v{r}ava-Lifshitz gravity by introducing a Maxwell field and a complex scalar field. We calculate the condensates of the charged operators in the dual CFTs when the mass square of the complex scalar filed is $m^2=-2/L^2$ and $m^2=0$, respectively. We compute the electrical conductivity of the \\hl superconductor in the probe approximation. In particular, it is found that there exists a spike in the conductivity for the case of the operator with scaling dimension one. These results are quite similar to those in the case of Schwarzschild-AdS black holes, which demonstrates that the holographic superconductivity is a robust phenomenon associated with asymptotic AdS black holes.
Black hole feedback in the luminous quasar PDS 456
Nardini, E; Gofford, J; Harrison, F A; Risaliti, G; Braito, V; Costa, M T; Matzeu, G A; Walton, D J; Behar, E; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Matt, G; Miller, J M; O'Brien, P T; Stern, D; Turner, T J; Ward, M J
2015-01-01
The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband X-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10^46 ergs per second is enough to provide the feedback required by models of black hole and host galaxy co-evolution.
Thermodynamics of de Sitter Black Holes: Thermal Cosmological Constant
Yuichi Sekiwa
2006-04-10
We study the thermodynamic properties associated with the black hole event horizon and the cosmological horizon for black hole solutions in asymptotically de Sitter spacetimes. We examine thermodynamics of these horizons on the basis of the conserved charges according to Teitelboim's method. In particular, we have succeeded in deriving the generalized Smarr formula among thermodynamical quantities in a simple and natural way. We then show that cosmological constant must decrease when one takes into account the quantum effect. These observations have been obtained if and only if cosmological constant plays the role of a thermodynamical state variable. We also touch upon the relation between inflation of our universe and a phase transition of black holes.
Hard, infrared black coating with very low outgassing
Kuzmenko, P J; Behne, D M; Casserly, T; Boardman, W; Upadhyaya, D; Boinapally, K; Gupta, M; Cao, Y
2008-06-02
Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} Torr liter/sec cm{sup 2}, comparable to bare stainless steel.
Aspects of Accretion Processes On a Rotating Black Hole
Sandip K. Chakrabarti
1996-11-10
We describe the most general nature of accretion and wind flows around a compact object and emphasize on the properties which are special to black hole accretion. The angular momentum distribution in the most general solution is far from Keplerian, and the non-Keplerian disks can include standing shock waves. We also present fully time dependent numerical simulation results to show that they agree with these analytical solutions. We describe the spectral properties of these accretion disks and show that the soft and hard states of the black hole candidates could be explained by the change of the accretion rate of the disk. We present fits of the observational data to demonstrate the presence of sub-Keplerian flows around black holes.
Satellite observations of thought experiments close to a black hole
S. K. Chakrabarti
2000-07-18
Since black holes are `black', methods of their identification must necessarily be indirect. Due to very special boundary condition on the horizon, the advective flow behaves in a particular way, which includes formation of centrifugal pressure dominated boundary layer or CENBOL where much of the infall energy is released and outflows are generated. The observational aspects of black holes must depend on the steady and time-dependent properties of this boundary layer. Several observational results are written down in this review which seem to support the predictions of thought experiments based on this advective accretion/outflow model. In future, when gravitational waves are detected, some other predictions of this model could be tested as well.
On the wave energy potential of Western Black Sea shelf
Galabov, Vasko
2013-01-01
In the present study we evaluate the approaches to estimate the wave energy potential of the western Black Sea shelf with numerical models. For the purpose of our evaluation and due to the lack of long time series of measurements in the selected area of the Black Sea, we compare the modeled mean wave power flux output from the SWAN wave model with the only available long term measurements from the buoy of Gelendzhik for the period 1997-2003 (with gaps). The forcing meteorological data for the numerical wave models for the selected years is extracted from the ERA Interim reanalysis of ECMWF (European Centre for Medium range Forecasts). For the year 2003 we also compare the estimated wave power with the modeled by SWAN, using ALADIN regional atmospheric model winds. We try to identify the shortcomings and limitations of the numerical modeling approach to the evaluation of the wave energy potential in Black Sea.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Banks, Elliot; Gauntlett, Jerome P
2015-01-01
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett
2015-10-11
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For Q-lattices and one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Sangrey, Trevor Joy
2012-01-01
Organizations Black Nation Thesis Pamphlets 4 Free 5 inMovement in the colonies: Thesis on the revolutionaryof the Black Nation Thesis. Berkeley: Racism Research
Scott, Clinton
2009-01-01
concentration in black shales: EXAFS evidence. Geochimica etOs and 2316Ma age for marine shale: implications forconcentration in black shales: EXAFS evidence. Geochimica et
Black Radicals Make for Bad Citizens: Undoing the Myth of the School to Prison Pipeline
Sojoyner, Damien M
2013-01-01
December 13). Prison pipeline hits Black students harder,http://politic365.com/2012/12/13/prison-pipeline-hits-black-The school-to-prison pipeline: Structuring legal reform. New
Understanding Black Male Athlete Social Responsibility (BMASR): A Case Study of an NBA Franchise
Agyemang, Kwame Jesse Asamoah
2012-07-16
While there is voluminous research on the Black male athlete, the literature does not touch on the notion of social responsibility. Thus, the purpose of this study was to garner perceptions of Black male athlete social ...
Are You Planning to Buy Energy-Efficient Products on Black Friday...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Are You Planning to Buy Energy-Efficient Products on Black Friday? Are You Planning to Buy Energy-Efficient Products on Black Friday? November 23, 2011 - 5:09am Addthis This week,...
Trace metal composition of suspended particulate matter in the water column of the Black Sea
Murray, James W.
Trace metal composition of suspended particulate matter in the water column of the Black Sea Ouz Keywords: Black Sea Geochemistry Biogeochemistry Biogeochemical cycle Trace metals Trace elements Tracers Particulates Suspended particulate matter Biogenic matter Biogenic material Plankton Planktonic metal
Microstructure and Optical Properties of Black Chrome Before and After Exposure to High Temperatures
Lapert, C.M.
2011-01-01
Black Chrome in Vacuum** Heat Treatment None, As-plated 200Black Chrome in Dry Air Heat Treatment None, As-plated 200°to short term heat treatments. The as-plated structure was
The Color of Self-Love: Exposing Racism in Black Female Masturbation Research
Frank, Elena
2010-01-01
Americans, Gender, and the New Racism. New York: Routledge,of Self-Love: Exposing Racism in Black Female Masturbationsexual deviance and construct racism and sexism. BLACK/WHITE
Interaction of Supermassive Black Holes with their Stellar and Dark Matter Environments
David Merritt
2004-10-04
A review of recent theoretical work on the interactions of supermassive single and binary black holes with their nuclear environments, highlighting ways in which the observed structure of nuclei can be used to constrain the formation history of black holes.
The preparation and analysis of ammonia base sulfite pulping liquor
Honstead, John Frederick
1950-01-01
. It was amntion- ed, however, t. . at during the test i' or SO in the Palmrose analysis all the sulfite was converted to sulfate~ which does not interfere with the ammonia-formol reaction. In addition the Palmrose analysis leaves the solution neutralized to a... satisfactorily but above . 5$ ammonia it does not seem advisable to attempt to obtain concentrations from pH measurements. For various solutions of ammonium hydroxide the change of pH with sulfur dioxide concentration was measured. These results are tabulated...
Oil palm vegetation liquor: a new source of phenolic bioactives
Sambandan, T. G.
Waste from agricultural products represents a disposal liability, which needs to be addressed. Palm oil is the most widely traded edible oil globally, and its production generates 85 million tons of aqueous by-products ...
Exact black hole solution with a minimally coupled scalar field
Cristian Martinez; Ricardo Troncoso; Jorge Zanelli
2004-06-13
An exact four-dimensional black hole solution of gravity with a minimally coupled self-interacting scalar field is reported. The event horizon is a surface of negative constant curvature enclosing the curvature singularity at the origin, and the scalar field is regular everywhere outside the origin. This solution is an asymptotically locally AdS spacetime. The strong energy condition is satisfied on and outside the event horizon. The thermodynamical analysis shows the existence of a critical temperature, below which a black hole in vacuum undergoes a spontaneous dressing up with a nontrivial scalar field in a process reminiscent of ferromagnetism.
Regular Black Holes in $f(R)$ Gravity
Rodrigues, Manuel E; Marques, Glauber T; Zanchin, Vilson T
2015-01-01
We obtain a class of regular black hole solutions in four-dimensional $f(R)$ gravity, $R$ being the curvature scalar, coupled to a nonlinear electromagnetic source. The metric formalism is used and static spherically symmetric spacetimes are assumed. The resulting metric functions are given by one real parameter family of solutions which are generalization of known regular black hole solutions in General Relativity. The known solutions of General Relativity are recovered when the free parameter vanish in which case one has $f(R)\\propto R$. We show that there are particular cases that violates only the strong energy condition.
Electromagnetic quasinormal modes of D-dimensional black holes II
A. López-Ortega
2007-06-20
By using the sixth order WKB approximation we calculate for an electromagnetic field propagating in D-dimensional Schwarzschild and Schwarzschild de Sitter black holes its quasinormal frequencies for the fundamental mode and first overtones. We study the dependence of these QN frequencies on the value of the cosmological constant and the spacetime dimension. We also compare with the known results for the gravitational perturbations propagating in the same background. Moreover we exactly compute the QN frequencies of the electromagnetic field propagating in D-dimensional massless topological black hole and for charged D-dimensional Nariai spacetime we exactly calculate the QN frequencies of the coupled electromagnetic and gravitational perturbations.
Supermassive Black Holes and the Evolution of Galaxies
D. Richstone; E. A. Ajhar; R. Bender; G. Bower; A. Dressler; S. M. Faber; A. V. Filippenko; K. Gebhardt; R. Green; L. C. Ho; J. Kormendy; T. Lauer; J. Magorrian; S. Tremaine
1998-10-23
Black holes, an extreme consequence of the mathematics of General Relativity, have long been suspected of being the prime movers of quasars, which emit more energy than any other objects in the Universe. Recent evidence indicates that supermassive black holes, which are probably quasar remnants, reside at the centers of most galaxies. As our knowledge of the demographics of these relics of a violent earlier Universe improve, we see tantalizing clues that they participated intimately in the formation of galaxies and have strongly influenced their present-day structure.
Relativistic Viscous Fluid Description of Microscopic Black Hole Wind
J. I. Kapusta
2001-05-25
Microscopic black holes explode with their temperature varying inversely as their mass. Such explosions would lead to the highest temperatures in the present universe, all the way to the Planck energy. Whether or not a quasi-stationary shell of matter undergoing radial hydrodynamic expansion surrounds such black holes is been controversial. In this paper relativistic viscous fluid equations are applied to the problem. It is shown that a self-consistent picture emerges of a fluid just marginally kept in local thermal equilibrium; viscosity is a crucial element of the dynamics.
Exploring higher dimensional black holes at the large hadron collider.
Harris, Chris M.; Palmer, M. J.; Parker, Michael A.; Richardson, P.
Preprint typeset in JHEP style - HYPER VERSION Cavendish-HEP-04/29 ATL-COM-PHYS-2004-067 Exploring Higher Dimensional Black Holes at the Large Hadron Collider C.M. Harris†, M.J. Palmer†, M.A. Parker†, P. Richardson‡, A. Sabetfakhri† and B.R. Webber... the Standard Model matter and gauge fields are confined to the physical three-branes in a higher dimensional space, it has been shown that most of the black hole decay products are Standard Model quanta emitted on the brane [7] and are therefore visible...
Low energy 2+1 string gravity; black hole solutions
A. A. Garcia Diaz; G. Gutierrez Cano
2014-12-17
In this report a detailed derivation of the dynamical equations for an n dimensional heterotic string theory of the Horowitz type is carried out in the string frame and in the Einstein frame too. In particular, the dynamical equations of the three dimensional string theory are explicitly given. The relation of the Horowitz Welch and Horne Horowitz string black hole solution is exhibited. The Chan Mann charged dilaton solution is derived and the subclass of string solutions field is explicitly identified. The stationary generalization, via SL(2;R) transformations, of the static (2+1) Horne Horowitz string black hole solution is given.
Schwarzschild black hole levitating in the hyperextreme Kerr field
V. S. Manko; E. Ruiz
2015-11-05
The equilibrium configurations between a Schwarzschild black hole and a hyperextreme Kerr object are shown to be described by a three-parameter subfamily of the extended double-Kerr solution. For this subfamily, its Ernst potential and corresponding metric functions, we provide a physical representation which employs as arbitrary parameters the individual Komar masses and relative coordinate distance between the sources. The calculation of horizon's local angular velocity induced in the Schwarzschild black hole by the Kerr constituent yields a simple expression inversely proportional to the square of the distance parameter.
Thermodynamics of Schrödinger black holes with hyperscaling violation
J. Sadeghi; B. Pourhassan; F. Pourasadollah
2012-11-06
In this work, we follow Kim and Yamada (JHEP1107 (2011) 120) and utilize AdS in light-cone frame to derive thermodynamic and transport properties of two kinds of Schr\\"{o}dinger black holes with hyperscaling violation. In that case, we show entropy and temperature are depend on $\\theta$. In $\\theta=0$ we see our results are agree with the work of Kim and Yamada. We also construct R-charged black hole with hyperscaling violation and obtain thermodynamics and transport properties.
Quantum-corrected finite entropy of noncommutative acoustic black holes
M. A. Anacleto; F. A. Brito; G. C. Luna; E. Passos; J. Spinelly
2015-01-31
In this paper we consider the generalized uncertainty principle in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for 2+1-dimensional noncommutative acoustic black holes. In our results we obtain an area entropy, a correction logarithmic in leading order, a correction term in subleading order proportional to the radiation temperature associated with the noncommutative acoustic black holes and an extra term that depends on a conserved charge. Thus, as in the gravitational case, there is no need to introduce the ultraviolet cut-off and divergences are eliminated.
Quantum-corrected finite entropy of noncommutative acoustic black holes
Anacleto, M A; Luna, G C; Passos, E; Spinelly, J
2015-01-01
In this paper we consider the generalized uncertainty principle in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for 2+1-dimensional noncommutative acoustic black holes. In our results we obtain an area entropy, a correction logarithmic in leading order, a correction term in subleading order proportional to the radiation temperature associated with the noncommutative acoustic black holes and an extra term that depends on a conserved charge. Thus, as in the gravitational case, there is no need to introduce the ultraviolet cut-off and divergences are eliminated.
Energy distribution in the dyadosphere of a charged black hole
S. S. Xulu
2003-04-22
The event horizon of a charged black hole is, according to Ruffini\\cite{Ruffini} and Preparata \\emph{et al.}\\cite{PreparataEtAl}, surrounded by a special region called the \\emph{dyadosphere} where the electromagnetic field exceeds the Euler-Heisenberg critical value for electron-positron pair production. We obtain the energy distribution in the dyadosphere region for a Reissner-Nordstr\\"{o}m black hole. We find that the energy-momentum prescriptions of Einstein, Landau-Lifshitz, Papapetrou, and Weinberg give the same and acceptable energy distribution.
Anomalies, Chern-Simons Terms and Black Hole Entropy
Tatsuo Azeyanagi; R. Loganayagam; Gim Seng Ng
2015-05-11
Recent derivations of Cardy-like formulae in higher dimensional field theories have opened up a way of computing, via AdS/CFT, universal contributions to black hole entropy from gravitational Chern-Simons terms. Based on the manifestly covariant formulation of the differential Noether charge for Chern-Simons terms proposed in arXiv:1407.6364, we compute the entropy and asymptotic charges for the rotating charged AdS black holes in higher dimensions at leading order of the fluid/gravity derivative expansion in the Einstein-Maxwell-Chern-Simons system. This gives a result that exactly matches the field theory predictions from Cardy-like formulae.
Role of Disk models in Indentifying Astrophysical Black Holes
Sandip K. Chakrabarti
2005-01-14
We discuss how disk models may limit the scope of identifying astrophysical black holes. We show that the standard Keplerian thin disk model, the thick disk model, slim disks, ADAFs etc. are fundamentally limited. We present the most complete solution to date called the advective accretion disk and discuss how it has the scope to address every observational aspects of a black hole. Though the magnetic field is not fully self-consistently taken care of yet, the details with which the present model can handle various issues successfully are astounding. We present some of the examples.
Greybody factors for Myers–Perry black holes
Boonserm, Petarpa; Chatrabhuti, Auttakit Ngampitipan, Tritos; Visser, Matt
2014-11-15
The Myers–Perry black holes are higher-dimensional generalizations of the usual (3+1)-dimensional rotating Kerr black hole. They are of considerable interest in Kaluza–Klein models, specifically within the context of brane-world versions thereof. In the present article, we shall consider the greybody factors associated with scalar field excitations of the Myers–Perry spacetimes, and develop some rigorous bounds on these greybody factors. These bounds are of relevance for characterizing both the higher-dimensional Hawking radiation, and the super-radiance, that is expected for these spacetimes.
Greybody factors for Myers-Perry black holes
Boonserm, Petarpa; Ngampitipan, Tritos; Visser, Matt
2014-01-01
The Myers-Perry black holes are higher-dimensional generalizations of the usual (3+1)-dimensional rotating Kerr black hole. They are of considerable interest in Kaluza-Klein models, specifically within the context of brane-world versions thereof. In the present article we shall consider the greybody factors associated with scalar field excitations of the Myers-Perry spacetimes, and develop some rigorous bounds on these greybody factors. These bounds are of relevance for characterizing both the higher-dimensional Hawking radiation, and the super-radiance, that is expected for these spacetimes.
Natural Cutoffs effect on Charged Rotating TeV-Scale Black Hole Thermodynamics
M. J. Soleimani; N. Abbasvandi; G. Gopir; Zainol Abidin Ibrahim; Shahidan Radiman; W. A. T Wan Abdullah
2015-10-15
We study the thermodynamics of charged rotating black hole in large extra dimensions scenario where quantum gravity effects are taken into account. We consider the effects of minimal length, minimal momentum, and maximal momentum as natural cutoffs on the thermodynamics of charged rotating TeV-scale black holes. In this framework the effect of the angular momentum and charge on the thermodynamics of the black hole are discussed. We focus also on frame dragging and Sagnac effect of the micro black holes.
Energy Distribution of a Schwarzschild Black Hole in a Magnetic Universe
Irina Radinschi
2000-10-25
We obtain the energy distribution of a Schwarzschild black hole in a magnetic universe in the Tolman prescription.
NREL's Black Silicon Increases Solar Cell Efficiency by Reducing Reflected Sunlight (Fact Sheet)
Not Available
2010-11-01
A fact sheet detailing the R&D 100 Award-winning Black Silicon Nanocatalytic Wet-Chemical Etch technology.
Gilli, Adrian
Origins and accumulation of organic matter in expanded Albian to Santonian black shale sequences laminated, Cenoma- nianSantonian black shale sequences contain between 2% and 15% organic carbon about the depositional conditions leading to the black shale accumulations. The low d13 Corg values
Entropy bound of a charged object and electrostatic self-energy in black holes
B. Linet
1999-11-30
Without pretending to any rigour, we find a general expression of the electrostatic self-energy in static black holes with spherical symmetry. We determine the entropy bound of a charged object by assuming the existence of thermodynamics for these black holes. By combining these two results, we show that the entropy bound does not depend on the considered black hole.
Dawson, Michael
Statistical Classification of Black-Capped (Poecile Atricapillus) and Mountain Chickadee (Poecile. Sturdy University of Alberta Both black-capped (Poecile atricapillus) and mountain chickadees (Poecile. Black-capped and mountain non-D notes were summarized as a set of 9 features and then analyzed by linear
Dawson, Michael
Black-capped (Poecile atricapillus) and mountain chickadee (Poecile gambeli) contact call contains black-capped and mountain chickadees, is among the most frequently produced call of each species of adult allopatric and sympatric black-capped and mountain chickadees in terms of nine acoustic features
Status Assessment of Laysan and Black-Footed Albatrosses, North Pacific Ocean, 19232005
Schweik, Charles M.
of Laysan and black-footed albatrosses. Photograph taken by Eric VanderWerf, Pacific Rim Conservation. #12Status Assessment of Laysan and Black-Footed Albatrosses, North Pacific Ocean, 19232005 Scientific;Status Assessment of Laysan and Black-Footed Albatrosses, North Pacific Ocean, 19232005 By Javier A
Marinomonas basaltis sp. nov., a marine bacterium isolated from black sand
Bae, Jin-Woo
Marinomonas basaltis sp. nov., a marine bacterium isolated from black sand Ho-Won Chang,1 Seong black sand in Soesoggak, Jeju island, Korea. The strain, designated J63T , was oxidase- and catalase- negative, rod-shaped bacterial strain, J63T , was isolated recently from black sand from Soesoggak, Jeju
Vibrio areninigrae sp. nov., a marine bacterium isolated from black sand
Bae, Jin-Woo
Vibrio areninigrae sp. nov., a marine bacterium isolated from black sand Ho-Won Chang,1 Seong Woon strain was isolated from black sand collected from Soesoggak, Jeju island, Korea. The strain, designated , was recently isolated from black sand collected from Soesoggak, Jeju island, Korea. In the present study
Does black carbon and humic materials in snow and ice Supervisor: Martin D. King
Royal Holloway, University of London
) burner technology changes the and optics properties of black carbon change. As little as 10 ng of Black carbon in snowpack is a factor of two more effective than carbon dioxide in changing global air with different black carbon and humic loadings, modeling the optical properties of the snow/ice and measuring
Proposed Studentship Does black carbon and humic materials in snow and ice
Royal Holloway, University of London
) black carbon is increasing or (b) burner technology changes the and optics properties of black carbon carbon dioxide in changing global air temperatures.2 The successful candidate will set-up and conductProposed Studentship Does black carbon and humic materials in snow and ice decay? Supervisors: Dr
Black carbon in Arctic snow and its effect on surface albedo
1 Black carbon in Arctic snow and its effect on surface albedo Stephen Warren, University wavelengths: ice is nearly transparent. Absorptive impurities: Black carbon (soot) Brown carbon (organics broadband albedo: 83% 71% (2) by addition of black carbon (BC) (20 ppb): 0.5% for r = 100 µm 1.6% for r
DEVELOPMENT OF AN ELK SIGHTABILITY MODEL FOR THE BLACK HILLS OF SOUTH DAKOTA
DEVELOPMENT OF AN ELK SIGHTABILITY MODEL FOR THE BLACK HILLS OF SOUTH DAKOTA BY EVAN C. PHILLIPS SIGHTABILITY MODEL FOR THE BLACK HILLS OF SOUTH DAKOTA Evan C. Phillips August 26, 2011 Elk (Cervus elaphus specific to the elk population that resides within the Black Hills of South Dakota. Sightability trials
A FAUNISTIC SURVEY OF NATIVE BEES IN THE MISSISSIPPI BLACK BELT PRAIRIE
Ray, David
A FAUNISTIC SURVEY OF NATIVE BEES IN THE MISSISSIPPI BLACK BELT PRAIRIE SURVEY OF NATIVE BEES IN THE MISSISSIPPI BLACK BELT PRAIRIE By Beverly A. McGee Smith of Study: A FAUNISTIC SURVEY OF NATIVE BEES IN THE MISSISSIPPI BLACK BELT
Black Box Design Ahmad Asi, Benjimin Chang, Mehdi Dadfarnia, Serge Kamta,
Austin, Mark
, Khan Black Box Design #12;Project Stakeholders ENES489P Black-Box Team and Advisors Military Logistics Use Case 4: Threats to System/Reliability Use Case 5: Maintenance Asi, Chang, Dadfarnia, Kamta, Khan Using the Black Box System Maintenance (has its own used case activity diagram) Data Rotator program
Zhu, Chen
Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona Abstract Naturally weathered feldspar surfaces in the Jurassic Navajo Sandstone at Black Mesa, Arizona-field dissolution rate discrepancy. At Black Mesa, feldspars in the Navajo Sandstone are dissolving at $105 times
Entropy Product Formula for spinning BTZ Black Hole
Pradhan, Parthapratim
2015-01-01
We investigate the thermodynamic properties of inner and outer horizons in the background of spinning BTZ(Ba\\~{n}ados,Teitelboim and Zanelli) black hole. We compute the \\emph{horizon radii product, the entropy product, the surface temperature product, the Komar energy product and the specific heat product} for both the horizons. We observe that the entropy product is \\emph{universal}(mass-independent), whereas the surface temperature product, Komar energy product and specific heat product are \\emph{not universal} because they all depends on mass parameter. We also show that the \\emph{First law} of black hole thermodynamics and \\emph {Smarr-Gibbs-Duhem } relations hold for inner horizon as well as outer horizon. The Christodoulou-Ruffini mass formula is derived for both the horizons. We further study the \\emph{stability} of such black hole by computing the specific heat for both the horizons. It has been observed that under certain condition the black hole possesses \\emph{second order phase transition}.
Entropy Product Formula for spinning BTZ Black Hole
Parthapratim Pradhan
2015-09-02
We investigate the thermodynamic properties of inner and outer horizons in the background of spinning BTZ(Ba\\~{n}ados,Teitelboim and Zanelli) black hole. We compute the \\emph{horizon radii product, the entropy product, the surface temperature product, the Komar energy product and the specific heat product} for both the horizons. We observe that the entropy product is \\emph{universal}(mass-independent), whereas the surface temperature product, Komar energy product and specific heat product are \\emph{not universal} because they all depends on mass parameter. We also show that the \\emph{First law} of black hole thermodynamics and \\emph {Smarr-Gibbs-Duhem } relations hold for inner horizon as well as outer horizon. The Christodoulou-Ruffini mass formula is derived for both the horizons. We further study the \\emph{stability} of such black hole by computing the specific heat for both the horizons. It has been observed that under certain condition the black hole possesses \\emph{second order phase transition}.
Unconventional Gravitational Excitation of a Schwarzschild Black Hole
P. T. Leung; Alec Maassen van den Brink; K. W. Mak; K. Young
2003-03-24
Besides the well-known quasinormal modes, the gravitational spectrum of a Schwarzschild black hole also has a continuum part on the negative imaginary frequency axis. The latter is studied numerically for quadrupole waves. The results show unexpected striking behavior near the algebraically special frequency $\\Omega=-4i$. This reveals a pair of unconventional damped modes very near $\\Omega$, confirmed analytically.
Dynamical mass ejection from black hole-neutron star binaries
Koutarou Kyutoku; Kunihito Ioka; Hirotada Okawa; Masaru Shibata; Keisuke Taniguchi
2015-08-19
We investigate properties of material ejected dynamically in the merger of black hole-neutron star binaries by numerical-relativity simulations. We systematically study the dependence of ejecta properties on the mass ratio of the binary, spin of the black hole, and equation of state of the neutron-star matter. Dynamical mass ejection is driven primarily by tidal torque, and the ejecta is much more anisotropic than that from binary neutron star mergers. In particular, the dynamical ejecta is concentrated around the orbital plane with a half opening angle of 10--20deg and often sweeps out only a half of the plane. The ejecta mass can be as large as ~0.1M_sun, and the velocity is subrelativistic with ~0.2--0.3c for typical cases. The ratio of the ejecta mass to the bound mass (disk and fallback components) is larger, and the ejecta velocity is larger, for larger values of the binary mass ratio, i.e., for larger values of the black-hole mass. The remnant black hole-disk system receives a kick velocity of O(100)km/s due to the ejecta linear momentum, and this easily dominates the kick velocity due to gravitational radiation. Structures of postmerger material, velocity distribution of the dynamical ejecta, fallback rates, and gravitational waves are also investigated. We also discuss the effect of ejecta anisotropy on electromagnetic counterparts, specifically a macronova/kilonova and synchrotron radio emission, developing analytic models.
AverYSummer 2013 Messenger Unleashing the Black erotic
Kunkle, Tom
AverYSummer 2013 Messenger Unleashing the Black erotic: ConferenCe & SympoSium Digging into Deep that will involve students interning on long-term projects at Avery Research Center as well. In short, the variety Exploring the Frederica Daly Papers ........................................................11 Digging
Magnetic wormholes and black universes with invisible ghosts
K. A. Bronnikov; P. A. Korolyov
2015-03-10
We construct explicit examples of globally regular static, spherically symmetric solutions in general relativity with scalar and electromagnetic fields describing traversable wormholes with flat and AdS asymptotics and regular black holes, in particular, black universes. (A black universe is a regular black hole with an expanding, asymptotically isotropic space-time beyond the horizon.) The existence of such objects requires invoking scalars with negative kinetic energy ("phantoms", or "ghosts"), which are not observed under usual physical conditions. To account for that, the so-called "trapped ghosts" were previously introduced, i.e., scalars whose kinetic energy is only negative in a restricted strong-field region of space-time and positive outside it. This approach leads to certain problems, including instability (as is illustrated here by derivation of an effective potential for spherical pertubations of such systems). In this paper, we use for model construction what we call "invisible ghosts", i.e., phantom scalar fields sufficiently rapidly decaying in the weak-field region. The resulting configurations contain different numbers of Killing horizons, from zero to four.
A Unitary Model of The Black Hole Evaporation
Yu-Lei Feng; Yi-Xin Chen
2014-12-16
A unitary effective field model of the black hole evaporation is proposed to satisfy almost the four postulates of the black hole complementarity (BHC). In this model, we enlarge a black hole-scalar field system by adding an extra radiation detector that couples with the scalar field. After performing a partial trace over the scalar field space, we obtain an effective entanglement between the black hole and the detector (or radiation in it). As the whole system evolves, the S-matrix formula can be constructed formally step by step. Without local quantum measurements, the paradoxes of the information loss and AMPS's firewall can be resolved. However, the information can be lost due to quantum decoherence, as long as some local measurement has been performed on the detector to acquire the information of the radiation in it. But unlike Hawking's completely thermal spectrum, some residual correlations can be found in the radiations. All these considerations can be simplified in a qubit model that provides a \\emph{modified quantum teleportation} to transfer the information via an EPR pairs.
Microfluidic control of axonal guidance *, Bryan Black1
Texas at Arlington, University of
Microfluidic control of axonal guidance Ling Gu1 *, Bryan Black1 *, Simon Ordonez1 , Argha Mondal1, producing turning angles of up to 906. Microfluidic flow simulations indicate that an axon may experience, no evidence exists to confirm the direct influence of microfluidic flow on axonal outgrowth and migration
Black hole free energy during charged collapse: a numerical study
Hugues Beauchesne; Ariel Edery
2012-05-19
We perform a numerical investigation of the thermodynamics during the collapse of a charged (complex) scalar field to a Reissner-Nordstr\\"om (RN) black hole in isotropic coordinates. Numerical work on gravitational collapse in isotropic coordinates has recently shown that the negative of the total Lagrangian approaches the Helmholtz free energy F= E-TS of a Schwarzschild black hole at late times of the collapse (where E is the black hole mass, T the temperature and S the entropy). The relevant thermodynamic potential for the RN black hole is the Gibbs free energy G=E-TS-$\\Phi_H$ Q where Q is the charge and $\\Phi_H$ the electrostatic potential at the outer horizon. In charged collapse, there is a large outgoing matter wave which prevents the exterior from settling quickly to a static state. However, the interior region is not affected significantly by the wave. We find numerically that the interior contribution to the Gibbs free energy is entirely gravitational and accumulates in a thin shell just inside the horizon. The entropy is gravitational in origin and one observes dynamically that it resides on the horizon. We also compare the numerical value of the interior Lagrangian to the expected analytical value of the interior Gibbs free energy for different initial states and we find that they agree to within 10-13%. The two values are approaching each other so that their difference decreases with more evolution time.
Bulk emission of scalars by a rotating black hole
M. Casals; S. R. Dolan; P. Kanti; E. Winstanley
2008-07-17
We study in detail the scalar-field Hawking radiation emitted into the bulk by a higher-dimensional, rotating black hole. We numerically compute the angular eigenvalues, and solve the radial equation of motion in order to find transmission factors. The latter are found to be enhanced by the angular momentum of the black hole, and to exhibit the well-known effect of superradiance. The corresponding power spectra for scalar fields show an enhancement with the number of dimensions, as in the non-rotating case. We compute the total mass loss rate of the black hole for a variety of black-hole angular momenta and bulk dimensions, and find that, in all cases, the bulk emission remains significantly smaller than the brane emission. The angular-momentum loss rate is also computed and found to have a smaller value in the bulk than on the brane. We present accurate bulk-to-brane emission ratios for a range of scenarios.
Quantum Jump from Singularity to Outside of Black Hole
Dündar, Furkan Semih
2015-01-01
Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as a part of his spacetime, then the semi-classical evolution would be non-unitary as viewed by him. Specifically, a free-falling observer inside the black hole would have a Hilbert space with non-unitary evolution; a quantum jump for particles encountering the singularity to outside of the horizon as part of late radiations in black hole evaporation. Accordingly, we elaborate the first postulate of black hole complementarity: freely falling observers who pass through the event horizon would have non-unitarity evolutions. The non-unitary evolution is such that it does not have physically measurable effects for them. Besides, no information would be lost in singularity. Taking the modified picture into account, the firewall paradox {can be} resolved, respecting No Drama. A by-product of our modification is that roughly half of the mass ...
Black carbon refractive index and morphology: a Laboratory study
Oxford, University of
cake 2.6 Heavy fuel oil 1.5 Figure 2: Global sources by fuel types [7]. A wide range of fuel types radiative properties derived from Mie theory and therefore limited to the assumption of spherical aerosol microphysical aerosol models, such as UKCA. This study derives the refractive indices black carbon (BC) aerosol
THE FIRST ACCURATE PARALLAX DISTANCE TO A BLACK HOLE
Miller-Jones, J. C. A.
Using astrometric VLBI observations, we have determined the parallax of the black hole X-ray binary V404 Cyg to be 0.418 [plus or minus sign] 0.024 mas, corresponding to a distance of 2.39 [plus or minus sign] 0.14 kpc, ...
Horizon of quantum black holes in various dimensions
Casadio, Roberto; Giugno, Andrea; Mureika, Jonas
2015-01-01
We adapt the horizon wave-function formalism to describe massive static spherically symmetric sources in a general $(1+D)$-dimensional space-time, for $D>3$ and including the $D=1$ case. We find that the probability $P_{\\rm BH} $ that such objects are (quantum) black holes behaves similarly to the probability in the $(3+1)$ framework for $D> 3$. In fact, for $D\\ge 3$, the probability increases towards unity as the mass grows above the relevant $D$-dimensional Planck scale $m_D$, the faster the larger $D$. In contrast, for $D=1$, we find the probability is comparably larger for smaller masses, but $P_{\\rm BH} < 0.5$, suggesting that such lower dimensional black holes are purely quantum and not classical objects. This result is consistent with recent observations that sub-Planckian black holes are governed by an effective two-dimensional gravitation theory. Lastly, we derive Generalised Uncertainty Principle relations for the black holes under consideration, and for all cases find a minimum length scale $L_D...
Reissner-Nordstrom black hole in dark energy background
Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh
2014-11-29
In this paper we propose a stationary solution of Einstein's field equations describing Reissner-Nordstrom black hole in dark energy background. It is to be regarded as the Reissner-Nordstrom black hole is embedded into the dark energy solution producing Reissner-Nordstrom-dark energy black hole. We find that the space-time geometry of Reissner-Nordstrom-dark energy solution is Petrov type $D$ in the classification of space-times. It is also shown that the embedded space-time possesses an energy-momentum tensor of the electromagnetic field interacting with the dark energy having negative pressure. We find the energy-momentum tensor for dark energy violates the the strong energy condition due to the negative pressure, whereas that of the electromagnetic field obeys the strong energy condition. It is shown that the time-like vector field for an observer in the Reissner-Nordstrom-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity of the horizons for the embedded dark energy black hole. The characteristic properties of relativistic dark energy based on the de Sitter solution is discussed in an appendix.
Small, dark, and heavy: But is it a black hole?
Visser, Matt; Liberati, Stefano; Sonego, Sebastiano
2009-01-01
Astronomers have certainly observed things that are small, dark, and heavy. But are these objects really black holes in the sense of general relativity? The consensus opinion is simply "yes", and there is very little "wriggle room". We discuss one of the specific alternatives.
Sensitivity of HAWC to Primordial Black Hole Bursts
Ukwatta, T N; MacGibbon, D Stump J H; Marinelli, S S; Yapici, T; Tollefson, K
2015-01-01
Primordial Black Holes (PBHs) are black holes that may have been created in the early Universe and could be as large as supermassive black holes or as small as the Planck scale. It is believed that a black hole has a temperature inversely proportional to its mass and will thermally emit all species of fundamental particles. PBHs with initial masses of 5.0 x 10^14 g should be expiring today with bursts of high-energy gamma radiation in the GeV/TeV energy range. The High Altitude Water Cherenkov (HAWC) observatory is sensitive to the high end of the PBH gamma-ray burst spectrum. Due to its large field of view, duty cycle above 90% and sensitivity up to 100 TeV, the HAWC observatory is well suited to perform a search for PBH bursts. We report that if the PBH explodes within 0.25 light years from Earth and within 26 degrees of zenith, HAWC will have a 95% probability of detecting the PBH burst at the 5 sigma level. Conversely, a null detection from a 2 year or longer HAWC search will set PBH upper limits which ar...
Zero Energy Rotating Accretion Flows near a Black Hole
Dongsu Ryu; Sandip K. Chakrabarti; Diego Molteni
1996-07-11
We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum $(\\lambda\\lsim\\lambda_b)$, most of the material is accreted into the black hole forming a quasi-spherical flow or a simple disk-like structure around it. When the flow has a large angular momentum (typically, larger than the marginally bound value, $\\lambda\\gsim\\lambda_{mb}$), almost no accretion into the black hole occurs. Instead, the flow produces a stable standing shock with one or more vortices behind it and is deflected away at the shock as a conical outgoing wind of higher entropy. If the flow has an angular momentum somewhat smaller than $\\lambda_{mb}$ $(\\lambda_{u}\\lsim\\lambda\\lsim\\lambda_{mb})$, a fraction (typically, $5-10$\\%) of the incoming material is accreted into the black hole, but the the flow structure formed is similar to that as for $\\lambda\\gsim\\lambda_{mb}$. Some of the deflected material is accreted back into the black hole, while the rest is blown away as an outgoing wind. These two cases with $\\lambda\\gsim\\lambda_u$ correspond those studied in the previous works by Molteni, Lanzafame, \\& Chakrabarti (1994) and Ryu \\etal (1995). However, the flow with an angular momentum close to the marginally stable value $(\\lambda_{ms})$ is found to be unstable. More specifically, if $\\lambda_b\\lsim\\lambda\\sim\\lambda_{ms}\\lsim\\lambda_u$, the flow displays a distinct periodicity in the sense that the inner part of the disk is built and
New solutions of exotic charged black holes and their stability
N. Farhangkhah
2015-10-18
We find a class of charged black hole solutions in third order Lovelock Gravity. To obtain this class of solutions, we are not confined to the usual assumption of maximal symmetry on the horizon and will consider the solution whose boundary is Einstein space with supplementary conditions on its Weyl tensor. The Weyl tensor of such exotic horizons exposes two charge-like parameter to the solution. These parameters in addition with the electric charge, cause different features in compare with the charged solution with constant-curvature horizon. For this class of asymptotically flat and (A)dS solutions, the electric charge dominates the behavior of the metric as r goes to zero, and thus the central singularity is always timelike. We also compute the thermodynamic quantities for these solutions and will show that the first law of thermodynamics is satisfied. We also show that the extreme black holes with nonconstant-curvature horizons whose Ricci scalar are zero or a positive constant could exist depending on the value of the electric charge and charged-like parameters. Finally, we investigate the stability of the black holes by analyzing the behavior of free energy and heat capacity specially in the limits of small and large horizon radius. We will show that in contrast with charged solution with constant-curvature horizon, a phase transition occurs between very small and small black holes from a stable phase to an unstable one, while the large black holes show stability to both perturbative and non-perturbative fluctuations. ?
The Hawking cascade from a black hole is extremely sparse
Finnian Gray; Sebastian Schuster; Alexander Van-Brunt; Matt Visser
2015-06-12
The Hawking flux from a black hole, (at least as seen from large distances), is extremely sparse and thin, with the average time between emission of successive Hawking quanta being hundreds of times larger than the natural timescale set by the energies of the emitted quanta. Some aspects of this result have been known for over 30 years, but have been largely forgotten, possibly because authors focussed mainly on the late-time high-temperature regime. We shall instead focus on the early-stage low-temperature regime, and shall both quantify and significantly extend these observations in a number of different ways. First we shall identify several natural dimensionless figures of merit, and thereby compare the mean time between emission of successive Hawking quanta to several quite natural timescales that can be associated with the emitted quanta, demonstrating that ratios of 300 or more are typical for emission of photons or gravitons from a Schwarzschild black hole. Furthermore these ratios are independent of the mass of the black hole as it slowly evolves. The situation for fermion emission (massless neutrinos) is actually worse. Second, we shall then show that the situation for Reissner-Nordstrom, Kerr, Kerr-Newman and "dirty" black holes is even worse. Third, we consider the effects of particle rest mass. Overall, the Hawking quanta are seen to be dribbling out of the black hole one at a time, in an extremely slow cascade of 3-body decays. This implies that the Hawking flux is subject to "shot noise". Observationally, the Planck spectrum of the Hawking flux can only be determined by collecting and integrating data over a very long time. We conclude by connecting these points back to various kinematic aspects of the Hawking evaporation process.
Black Holes in Galaxy Mergers: Evolution of Quasars
Philip F. Hopkins; Lars Hernquist; Thomas J. Cox; Tiziana Di Matteo; Paul Martini; Brant Robertson; Volker Springel
2005-06-13
Based on numerical simulations of gas-rich galaxy mergers, we discuss a model in which quasar activity is tied to the self-regulated growth of supermassive black holes in galaxies. Nuclear inflow of gas attending a galaxy collision triggers a starburst and feeds black hole growth, but for most of the duration of the starburst, the black hole is heavily obscured by surrounding gas and dust which limits the visibility of the quasar, especially at optical and UV wavelengths. Eventually, feedback energy from accretion heats the gas and expels it in a powerful wind, leaving a 'dead quasar'. Between buried and dead phases there is a window during which the galaxy would be seen as a luminous quasar. Because the black hole mass, radiative output, and distribution of obscuring gas and dust all evolve strongly with time, the duration of this phase of observable quasar activity depends on both the waveband and imposed luminosity threshold. We determine the observed and intrinsic lifetimes as a function of luminosity and frequency, and calculate observable lifetimes ~10 Myr for bright quasars in the optical B-band, in good agreement with empirical estimates and much smaller than the black hole growth timescales ~100 Myr, naturally producing a substantial population of 'buried' quasars. However, observed and intrinsic energy outputs converge in the IR and hard X-ray bands as attenuation becomes weaker and chances of observation greatly increase. We obtain the distribution of column densities along sightlines in which the quasar is seen above a given luminosity, and find that our result agrees remarkably well with observed estimates of the column density distribution from the SDSS for appropriate luminosity thresholds. (Abridged)
Bernstein, Lenny
2008-01-01
A. , 2004: Feedstock recycling of plastics in Japan. PolymerRecycling, (bark, black Non-wood liquor) fibres Biomass, Biogas, Solar drying n.a. Blended cement Geo-polymers
Sacrificial Protective Coating Materials That Can Be Regenerated...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
U.S. industries, the process of concentrating weak black liquor (WBL) in the pulp and paper industry is identified as one of the largest energy reduction opportunities for...
ITP Industrial Distributed Energy: CHP and Bioenergy for Landfills...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
z Black Liquor z Blast Furnace Gas z Coalbed Methane z Coke Oven Gas z Crop Residues z Food Processing Waste z Industrial VOC's z Landfill Gas z Municipal Solid Waste z...
Grace, T. M.; Wag, K. J.; Horton, R. R.; Frederick, W. J.
1994-01-01
This paper describes an improved model of char burning during black liquor combustion that is capable of predicting net rates of sulfate reduction to sulfide as well as carbon burnup rates. Enhancements include a proper ...
Optical properties of black hole in the presence of plasma: shadow
Atamurotov, Farruh
2015-01-01
Photon motion around the black hole surrounded with a homogenous plasma is studied. It is shown that under influence of plasma the observed size of shadow of the spherical symmetric black hole becomes smaller than that in the vacuum case. However the photon sphere around the spherical symmetric black hole is left unchanged under the plasma influence. The energy emission from the black hole in plasma is also studied and it is shown that with the increase of the dimensionless plasma parameter the maximum value of energy emission rate from the black hole decreases.
Hawking Radiation of Topological Massive Warped-AdS3 Black Hole Families
Ganim Gecim; Yusuf Sucu
2014-10-15
We investigate the Dirac particles tunnelling as a radiation of Warped AdS$_{3}$ black hole family in Topological Massive Gravity. Using the Hamilton-Jacobi method, we discuss tunnelling probability and Hawking temperature of the spin-1/2 particles for the black hole and its extremal cases. We observe that the Hawking temperature of the non-extremal black hole higher than the extremal black hole when $\\omega <\\frac{2\\ r_{0}}{3}$, because the non-extremal black hole become unstable in this case.
A comparative study of Dirac quasinormal modes of charged black holes in higher dimensions
Sayan K. Chakrabarti
2009-03-26
In this work we study the Dirac quasinormal modes of higher dimensional charged black holes. Higher dimensional Reissner-N\\"{o}rdstrom type black holes as well as charged black holes in Einstein Gauss-Bonnet theories are studied for Fermionic perturbations using WKB method. A comparative study of the quasinormal modes in the two different theories of gravity has been performed. The beahviour of the frequencies with the variation of black hole parameters as well as with the variation of spacetime dimensions are done. We also study the large multipole number limit of the black hole potential in order to look for an analytic expression for the frequencies.
Seamons, Kent E.
of Geological Sciences, BYU Master of Science Geologic sequestration of anthropogenic carbon dioxide (CO2, and Black Dragon Member of the Triassic Moenkopi Formation for CO2 Storage and Sequestration at Woodside Formation, for CO2 Sequestration at Woodside Field, East-central Utah Walter Harston Department
A comparison of black hole growth in galaxy mergers with Gasoline and Ramses
Gabor, J M; Volonteri, Marta; Bournaud, Frédéric; Bellovary, Jillian; Governato, Fabio; Quinn, Thomas
2015-01-01
Supermassive black hole dynamics during galaxy mergers is crucial in determining the rate of black hole mergers and cosmic black hole growth. As simulations achieve higher resolution, it becomes important to assess whether the black hole dynamics is influenced by the treatment of the interstellar medium in different simulation codes. We here compare simulations of black hole growth in galaxy mergers with two codes: the Smoothed Particle Hydrodynamics code Gasoline, and the Adaptive Mesh Refinement code Ramses. We seek to identify predictions of these models that are robust despite differences in hydrodynamic methods and implementations of sub-grid physics. We find that the general behavior is consistent between codes. Black hole accretion is minimal while the galaxies are well-separated (and even as they "fly-by" within 10 kpc at first pericenter). At late stages, when the galaxies pass within a few kpc, tidal torques drive nuclear gas inflow that triggers bursts of black hole accretion accompanied by star fo...
Broader source: Energy.gov [DOE]
This advisory describes a security issue in the BlackBerry Administration API component. Successful exploitation of the vulnerability could result in information disclosure and partial denial of service (DoS). The BlackBerry Administration API is a BlackBerry Enterprise Server component that is installed on the server that hosts the BlackBerry Administration Service. The BlackBerry Administration API contains multiple web services that receive API requests from client applications. The BlackBerry Administration API then translates requests into a format that the BlackBerry Administration Service can process.
"Separations: Dust to Dust" or " You Can't Escape Em"
Massey, R. G.
1985-01-01
crystallization is being developed for concentrating black liquor in the paper making process. Evaporation has been applied to the plating process to eliminate a waste disposal problem. INTRODUCTI ON In the broadest sense, separation is perhaps the most... desalting processes, Concentrex, Inc., (formerly Concentration Specialists), with support from the DOE, undertook the development of a freeze process for concentrating black liquor, a process stream in the paper making process. In the pulp and paper...
Primordial Black Holes: Observational Characteristics of The Final Evaporation
Ukwatta, T N; Linnemann, J T; MacGibbon, J H; Marinelli, S S; Yapici, T; Tollefson, K
2015-01-01
Many early universe theories predict the creation of Primordial Black Holes (PBHs). PBHs could have masses ranging from the Planck mass to $10^5$ solar masses or higher depending on the size of the universe at formation. A Black Hole (BH) has a Hawking temperature which is inversely proportional to its mass. Hence a sufficiently small BH will quasi-thermally radiate particles at an ever-increasing rate as emission lowers its mass and raises its temperature. The final moments of this evaporation phase should be explosive and its description dependent on the particle physics model. In this work we investigate the final few seconds of BH evaporation using the Standard Model of particle physics incorporating the most recent LHC results and calculate energy dependent PBH burst light curves in the GeV/TeV energy range. Moreover, we explore PBH burst search methods and potential observational PBH burst signatures relevant to very high energy gamma-ray observatories.
Instability of black hole formation in gravitational collapse
Joshi, Pankaj S.; Malafarina, Daniele
2011-01-15
We consider here the classic scenario given by Oppenheimer, Snyder, and Datt, for the gravitational collapse of a massive matter cloud, and examine its stability under the introduction of small tangential stresses. We show, by offering an explicit class of physically valid tangential stress perturbations, that an introduction of tangential pressure, however small, can qualitatively change the final fate of collapse from a black hole final state to a naked singularity. This shows instability of black hole formation in collapse and sheds important light on the nature of cosmic censorship hypothesis and its possible formulations. The key effect of these perturbations is to alter the trapped surface formation pattern within the collapsing cloud and the apparent horizon structure. This allows the singularity to be visible, and implications are discussed.
Circularization of Tidally Disrupted Stars around Spinning Supermassive Black Holes
Hayasaki, Kimitake; Loeb, Abraham
2015-01-01
We study the circularization of tidally disrupted stars on bound orbits around spinning supermassive black holes by performing three-dimensional smoothed particle hydrodynamic simulations with Post-Newtonian corrections. Our simulations reveal that debris circularization depends sensitively on the efficiency of radiative cooling. There are two stages in debris circularization if radiative cooling is inefficient: first, the stellar debris streams self-intersect due to relativistic apsidal precession; shocks at the intersection points thermalize orbital energy and the debris forms a geometrically thick, ring-like structure around the black hole. The ring rapidly spreads via viscous diffusion, leading to the formation of a geometrically thick accretion disk. In contrast, if radiative cooling is efficient, the stellar debris circularizes due to self-intersection shocks and forms a geometrically thin ring-like structure. In this case, the dissipated energy can be emitted during debris circularization as a precurso...
Information Preservation and Weather Forecasting for Black Holes
S. W. Hawking
2014-01-22
It has been suggested [1] that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the CPT invariance of quantum gravity and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that gravitational collapse produces apparent horizons but no event horizons behind which information is lost. This proposal is supported by ADS-CFT and is the only resolution of the paradox compatible with CPT. The collapse to form a black hole will in general be chaotic and the dual CFT on the boundary of ADS will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity.
Black hole energy extraction via stationary scalar clouds
Wilson-Gerow, Jordan
2015-01-01
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the threshold for energy extraction via superradiance. Motivated by the electromagnetic Blandford-Znajek (BZ) mechanism, we explore whether scalar clouds could serve as a proxy for the force-free magnetosphere in the BZ process. We find that a stationary energy-extracting scalar cloud solution exists when the reflecting mirror is replaced by a semi-permeable surface which allows the cloud to radiate some energy to infinity while maintaining self-sustained superradiance. The radial energy flux displays the same behaviour for rapidly rotating holes as magnetohydrodynamic simulations predict for the BZ mechanism.
Black hole energy extraction via stationary scalar clouds
Jordan Wilson-Gerow; Adam Ritz
2015-09-22
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the threshold for energy extraction via superradiance. Motivated by the electromagnetic Blandford-Znajek (BZ) mechanism, we explore whether scalar clouds could serve as a proxy for the force-free magnetosphere in the BZ process. We find that a stationary energy-extracting scalar cloud solution exists when the reflecting mirror is replaced by a semi-permeable surface which allows the cloud to radiate some energy to infinity while maintaining self-sustained superradiance. The radial energy flux displays the same behaviour for rapidly rotating holes as magnetohydrodynamic simulations predict for the BZ mechanism.
Measurement of Mass and Spin of Black Holes with QPOs
B. Aschenbach
2007-10-18
There are now four low mass X-ray binaries with black holes which show twin resonant-like HFQPOs. Similar QPOs might have been found in Sgr A*. I review the power spectral density distributions of the three X-ray flares and the six NIR flares published for Sgr A* so far, in order to look for more similarities than just the frequencies between the microquasar black holes and Sgr A*. The three X-ray flares of Sgr A* are re-analysed in an identical way and white noise probabilities from their power density distributions are given for the periods reported around 1100 s. Progress of the resonant theory using the anomalous orbital velocity effect is summarized.
Powering AGNs with super-critical black holes
A. Avgoustidis; R. Jimenez; L. Alvarez-Gaume; M. A. Vazquez-Mozo
2009-05-13
We propose a novel mechanism for powering the central engines of Active Galactic Nuclei through super-critical (type II) black hole collapse. In this picture, ~$10^3 M_\\odot$ of material collapsing at relativistic speeds can trigger a gravitational shock, which can eject a large percentage of the collapsing matter at relativistic speeds, leaving behind a "light" black hole. In the presence of a poloidal magnetic field, the plasma collimates along two jets, and the associated electron synchrotron radiation can easily account for the observed radio luminosities, sizes and durations of AGN jets. For Lorentz factors of order 100 and magnetic fields of a few hundred $\\mu G$, synchrotron electrons can shine for $10^6$ yrs, producing jets of sizes of order 100 kpc. This mechanism may also be relevant for Gamma Ray Bursts and, in the absence of magnetic field, supernova explosions.
Asymptotically flat black holes with scalar hair: a review
Herdeiro, Carlos A R
2015-01-01
We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the spacetime symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Asymptotically flat black holes with scalar hair: a review
Carlos A. R. Herdeiro; Eugen Radu
2015-04-30
We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the spacetime symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Dilatonic wormholes: construction, operation, maintenance and collapse to black holes
Sean A. Hayward; Sung-Won Kim; Hyunjoo Lee
2001-10-18
The CGHS two-dimensional dilaton gravity model is generalized to include a ghost Klein-Gordon field, i.e. with negative gravitational coupling. This exotic radiation supports the existence of static traversible wormhole solutions, analogous to Morris-Thorne wormholes. Since the field equations are explicitly integrable, concrete examples can be given of various dynamic wormhole processes, as follows. (i) Static wormholes are constructed by irradiating an initially static black hole with the ghost field. (ii) The operation of a wormhole to transport matter or radiation between the two universes is described, including the back-reaction on the wormhole, which is found to exhibit a type of neutral stability. (iii) It is shown how to maintain an operating wormhole in a static state, or return it to its original state, by turning up the ghost field. (iv) If the ghost field is turned off, either instantaneously or gradually, the wormhole collapses into a black hole.
Global Inflow and Outflow Solutions (GIOS) around a Black Hole
Sandip K. Chakrabarti
1998-12-09
Twenty five years have passed by since models of accretions and jets have separately emerged. Today, it is understood that these two objects are related to each other in a fundamental way. In a binary system, matter from an accretion disk enters into a black hole. A part of it is bounced back because of the centrifugal barrier, radiation pressure or magnetohydrodynamic effects, to form jets and bipolar outflows which carry away excess angular momentum. In the case of AGNs containing black holes, accretion disks form out of stellar winds and similar processes as above form cosmic radio jets. We present a general review of the study of the accretion disks and outflows in a coherent manner, especially emphasizing global inflow-outflow solutions (GIOS). We also present a few observational consequences of wind production from the accretion disks on spectral properties of the accretion disks.
Are black holes in an ekpyrotic phase possible?
J. C. S. Neves
2015-09-10
The ekpyrotic phase (a slow contraction cosmic phase before the current expansion phase) manages to solve the main problems of the standard cosmology by means of a scalar field interpreted as an isotropic cosmic fluid in the Friedmann equation. Moreover, this phase generates a nearly scale-invariant spectrum of perturbations in agreement with the latest data. Then, the ekpyrotic mechanism is a serious possibility to the inflationary model. In this work, we point out that it is impossible to generate a black hole with spherical symmetry supported by an isotropic fluid in this scenario. Using the approach of deforming metrics to obtain solutions with an isotropic energy-momentum tensor, we show that the stiff fluid, dominant in the ekpyrotic phase, does not support these black holes.
Black hole lightning due to particle acceleration at subhorizon scales
Aleksi?, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Godinovi?, N; Muñoz, A González; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzi?, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J
2014-01-01
Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.
CP Violation and Baryogenesis in the Presence of Black Holes
Tom Banks; Willy Fischler
2015-05-16
In a recent paper[1] Kundu and one of the present authors showed that there were transient but observable CP violating effects in the decay of classical currents on the horizon of a black hole, if the Lagrangian of the Maxwell field contained a CP violating angle {\\theta}. In this paper we demonstrate that a similar effect can be seen in the quantum mechanics of QED: a non-trivial Berry phase in the QED wave function is produced by in-falling electric charges. We also investigate whether CP violation, of this or any other type, might be used to produce the baryon asymmetry of the universe, in models where primordial black hole decay contributes to the matter content of the present universe. This can happen both in a variety of hybrid inflation models, and in the Holographic Space-time (HST) model of inflation[2].
Short distance signatures in Cosmology: Why not in Black Holes?
Roberto Casadio; Laura Mersini
2002-08-07
Current theoretical investigations seem to indicate the possibility of observing signatures of short distance physics in the Cosmic Microwave Background spectrum. We try to gain a deeper understanding on why all information about this regime is lost in the case of Black Hole radiation but not necessarily so in a cosmological setting by using the moving mirror as a toy model for both backgrounds. The different responses of the Hawking and Cosmic Microwave Background spectra to short distance physics are derived in the appropriate limit when the moving mirror mimics a Black Hole background or an expanding universe. The different sensitivities to new physics, displayed by both backgrounds, are clarified through an averaging prescription that accounts for the intrinsic uncertainty in their quantum fluctuations. We then proceed to interpret the physical significance of our findings for time-dependent backgrounds in the light of nonlocal string theory.
Optical properties of black hole in the presence of plasma: shadow
Farruh Atamurotov; Bobomurat Ahmedov; Ahmadjon Abdujabbarov
2015-08-28
We have studied photon motion around axially symmetric rotating Kerr black hole in the presence of plasma with radial power-law density. It is shown that in the presence of plasma the observed shape and size of shadow changes depending on i) plasma parameters, ii) black hole spin and iii) inclination angle between observer plane and axis of rotation of black hole. In order to extract pure effect of plasma influence on black hole image the particular case of the Schwarzschild black hole has also been investigated and it has been shown that i) the photon sphere around the spherical symmetric black hole is left unchanged under the plasma influence, ii) however the Schwarzschild black hole shadow size in plasma is reduced due to the refraction of the electromagnetic radiation in plasma environment of black hole. The study of the energy emission from the black hole in plasma shows that in the presence of plasma the maximal energy emission rate from the black hole decreases.
Positive specific heat of the quantum corrected dilaton black hole
D. Grumiller; W. Kummer; D. V. Vassilevich
2003-06-20
Path integral quantization of dilaton gravity in two dimensions is applied to the CGHS model to the first nontrivial order in matter loops. Our approach is background independent as geometry is integrated out exactly. The result is an effective shift of the Killing norm: the apparent horizon becomes smaller. The Hawking temperature which is constant to leading order receives a quantum correction. As a consequence, the specific heat becomes positive and proportional to the square of the black hole mass.
Quasi-black holes: general features and purely field configurations
K. A. Bronnikov; O. B. Zaslavskii
2015-04-27
Objects that are on the threshold of forming the horizon but never collapse are called quasi-black holes (QBHs). We discuss the properties of the general spherically symmetric QBH metric without addressing its material source, including its limiting cases as the corresponding small parameter tends to zero. We then show that QBHs can exist among self-gravitating configurations of electromagnetic and dilatonic scalar fields without matter. These general results are illustrated by explicit examples of exact solutions.
Black holes vs. naked singularities formation in collapsing Einstein's clusters
S. Jhingan; G. Magli
2000-01-10
Non-static, spherically symmetric clusters of counter-rotating particles, of the type first introduced by Einstein, are analysed here. The initial data space can be parameterized in terms of three arbitrary functions, namely; initial density, velocity and angular momentum profiles. The final state of collapse, black hole or naked singularity, turns out to depend on the order of the first non-vanishing derivatives of such functions at the centre. The work extends recent results by Harada, Iguchi and Nakao.
Void morphology in polyethylene/carbon black composites
Marr, D.W.M.; Wartenberg, M.; Schwartz, K.B.
1996-12-31
A combination of small angle neutron scattering (SANS) and contrast matching techniques is used to determine the size and quantity of voids incorporated during fabrication of polyethylene/carbon black composites. The analysis used to extract void morphology from SANS data is based on the three-phase model of microcrack determination via small angle x-rayscattering (SAXS) developed by W.Wu{sup 12} and applied to particulate reinforced composites.
Holographic superconductor developed in BTZ black hole background with backreactions
Yunqi Liu; Qiyuan Pan; Bin Wang
2011-06-22
We develop a holographic superconductor in BTZ black hole background with backreactions. We investigate the influence of the backreaction on the condensation of the scalar hair and the dynamics of perturbation in the background spacetime. When the Breitenlohner-Freedman bound is approached, we argue that only one of two possible operators can reflect the real property of the condensation in the holographic superconductor. This argument is supported by the investigation in dynamics.
Anti-de Sitter black holes in supergravity
Chong, Zhiwei
2009-06-02
-Generating Procedure . . . . . . . . . . . . . . . . 22 1. O(4,4) Symmetry of the Reduced D = 3 Theory . . . 23 2. O(1,1)4 Transformation of a Reduced Uncharged Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 30 C. 4-Charge Rotating NUT Solution... of supersymmetric five-dimensional AdS black holes and that calculated from the counting of microstates in the D-brane models involving giant gravitons in the very recent paper [22]. In Chapter IV, we will present the details in constructing 12 these five...
Power Law Corrections to BTZ Black Hole Entropy
Dharm Veer Singh
2014-11-14
We study the quantum scalar field in the background of BTZ black hole and evaluate the entanglement entropy of the non-vacuum states. The entropy is proportional to the area of event horizon for the ground state, but the area law is violated in the case of non-vacuum states (first excited state and mixed states) and the corrections scale as power law.
Jets from Tidal Disruptions of Stars by Black Holes
Julian H. Krolik; Tsvi Piran
2012-02-07
Tidal disruption of main sequence stars by black holes has generally been thought to lead to a signal dominated by UV emission. If, however, the black hole spins rapidly and the poloidal magnetic field intensity on the black hole horizon is comparable to the inner accretion disk pressure, a powerful jet may form whose luminosity can easily exceed the thermal UV luminosity. When the jet beam points at Earth, its non-thermal luminosity can dominate the emitted spectrum. The thermal and non-thermal components decay differently with time. In particular, the thermal emission should remain roughly constant for a significant time after the period of maximum accretion, beginning to diminish only after a delay, whereas after the peak accretion rate, the non-thermal jet emission decays, but then reaches a plateau. Both transitions are tied to a characteristic timescale $t_{\\rm Edd}$ at which the accretion rate falls below Eddington. Making use of this timescale in a new parameter-inference formalism for tidal disruption events with significant emission from a jet, we analyze the recent flare source Swift J2058. It is consistent with an event in which a main sequence solar-type staris disrupted by a black hole of mass $\\sim 4 \\times 10^7 M_{\\odot}$. The beginning of the flat phase in the non-thermal emission from this source can possibly be seen in the late-time lightcurve. Optical photometry over the first $\\simeq 40$ d of this flare is also consistent with this picture, but is only weakly constraining because the bolometric correction is very uncertain. We suggest that future searches for main sequence tidal disruptions use methods sensitive to jet radiation as well as to thermal UV radiation.
Barrow Black Carbon Source and Impact Study Final Campaign Report
Barrett, Tate
2014-07-01
The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.
Global solutions for higher-dimensional stretched small black holes
Chen, C.-M.; Gal'tsov, Dmitri V.; Ohta, Nobuyoshi; Orlov, Dmitry G.
2010-01-15
Small black holes in heterotic string theory have a vanishing horizon area at the supergravity level, but the horizon is stretched to the finite radius AdS{sub 2}xS{sup D-2} geometry once higher curvature corrections are turned on. This has been demonstrated to give good agreement with microscopic entropy counting. Previous considerations, however, were based on the classical local solutions valid only in the vicinity of the event horizon. Here we address the question of global existence of extremal black holes in the D-dimensional Einstein-Maxwell-Dilaton theory with the Gauss-Bonnet term introducing a variable dilaton coupling a as a parameter. We show that asymptotically flat black holes exist only in a bounded region of the dilaton couplings 0=}5 (but not for D=4) the allowed range of a includes the heterotic string values. For a>a{sub cr} numerical solutions meet weak naked singularities at finite radii r=r{sub cusp} (spherical cusps), where the scalar curvature diverges as |r-r{sub cusp}|{sup -1/2}. For D{>=}7 cusps are met in pairs, so that solutions can be formally extended to asymptotically flat infinity choosing a suitable integration variable. We show, however, that radial geodesics cannot be continued through the cusp singularities, so such a continuation is unphysical.
Can black holes and naked singularities be detected in accelerators?
R. Casadio; B. Harms
2002-01-07
We study the conditions for the existence of black holes that can be produced in colliders at TeV-scale if the space-time is higher dimensional. On employing the microcanonical picture, we find that their life-times strongly depend on the details of the model. If the extra dimensions are compact (ADD model), microcanonical deviations from thermality are in general significant near the fundamental TeV mass and tiny black holes decay more slowly than predicted by the canonical expression, but still fast enough to disappear almost instantaneously. However, with one warped extra dimension (RS model), microcanonical corrections are much larger and tiny black holes appear to be (meta)stable. Further, if the total charge is not zero, we argue that naked singularities do not occur provided the electromagnetic field is strictly confined on an infinitely thin brane. However, they might be produced in colliders if the effective thickness of the brane is of the order of the fundamental length scale (~1/TeV).
Zero energy rotating accretion flows near a black hole
Ryu, D; Molteni, D; Ryu, Dongsu; Chakrabarti, Sandip K; Molteni, Diego
1996-01-01
We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum (\\lambda\\lsim\\lambda_b), most of the material is accreted into the black hole forming a quasi-spherical flow or a simple disk-like structure around it. When the flow has a large angular momentum (typically, larger than the marginally bound value, \\lambda\\gsim\\lambda_{mb}), almost no accretion into the black hole occurs. Instead, the flow produces a stable standing shock with one or more vortices behind it and is deflected away at the shock as a conical outgoing wind of higher entropy. If the flow has an angular momentum somewhat smaller than \\lambda_{mb} (\\lambda_{u}\\lsim\\lambda\\lsim\\lambda_{mb}), a fraction (typically, 5-10...
Functional determinants, index theorems, and exact quantum black hole entropy
Murthy, Sameer
2015-01-01
The exact quantum entropy of BPS black holes can be evaluated using localization in supergravity. An important ingredient in this program, that has been lacking so far, is the one-loop effect arising from the quadratic fluctuations of the exact deformation (the $Q\\mathcal{V}$ operator). We compute the fluctuation determinant for vector multiplets and hyper multiplets around $Q$-invariant off-shell configurations in four-dimensional $\\mathcal{N}=2$ supergravity with $AdS_{2} \\times S^{2}$ boundary conditions, using the Atiyah-Bott fixed-point index theorem and a subsequent zeta function regularization. Our results extend the large-charge on-shell entropy computations in the literature to a regime of finite charges. Based on our results, we present an exact formula for the quantum entropy of BPS black holes in $\\mathcal{N}=2$ supergravity. We explain cancellations concerning $\\frac18$-BPS black holes in $\\mathcal{N}=8$ supergravity that were observed previously. We also make comments about the interpretation of...