169 Search Results

The growing demand for rare earth elements (REEs) in clean energy and high-tech industries underscores the need for sustainable recovery methods and a reliable supply of processing chemicals. Here, we establish a microbial platform using the acid-tolerant yeast Issatchenkia orientalis SD108 to produce bio-oxalic acid for REE recovery. By introducing an oxaloacetate cleavage pathway and applying metabolic engineering, the engineered strain produces 39.53 g·L^-1 oxalic acid at pH 4.0 in fed-batch fermentation. The crude fermentation broth, used without purification, efficiently precipitates over 99% neodymium (Nd), 99% dysprosium (Dy), and 98% lanthanum (La) from individual REE chloride solutions. Recovery from amore » low-grade ore leachate achieves over 99% total recovery. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirm that REE oxalates precipitated with bio-oxalic acid closely resemble those obtained using commercial oxalic acid. Techno-economic analysis (TEA) and life cycle assessment (LCA) further demonstrate that bio-oxalic acid can be produced at a competitive price of $1.79·kg^-1 while reducing carbon intensity (CI) by 112% to 63.5% with and without electricity displacement, respectively, relative to the fossil-based benchmark. These results highlight bio-oxalic acid as a green, economically viable alternative to synthetic oxalate for sustainable REE recovery.« less

September 2023 marks the 50th anniversary of the Electronic Visualization Laboratory (EVL) at University of Illinois Chicago (UIC). EVL's introduction of the CAVE Automatic Virtual Environment in 1992, the first widely replicated, projection-based, walk-in, virtual-reality (VR) system in the world, put EVL at the forefront of collaborative, immersive data exploration and analytics. However, the journey did not begin then. Since its founding in 1973, EVL has been developing tools and techniques for real-time, interactive visualizations—pillars of VR. But EVL's culture is also relevant to its successes, as it has always been an interdisciplinary lab that fosters teamwork, where each person'smore » expertise contributes to the development of the necessary tools, hardware, system software, applications, and human interface models to solve problems. Over the years, as multidisciplinary collaborations evolved and advanced scientific instruments and data resources were distributed globally, the need to access and share data and visualizations while working with colleagues, local and remote, synchronous and asynchronous, also became important fields of study. This paper is a retrospective of EVL's past 50 years that surveys the many networked, immersive, collaborative visualization and VR systems and applications it developed and deployed, as well as lessons learned and future plans.« less

Electrolysis of water to produce hydrogen from renewable electricity is an extremely attractive strategy to reduce energy dependence on fossil fuels. Development of membrane and ionomer materials that maintain high performance with long lifetimes is needed. We developed and investigated the performance and durability of a series of polyethylene-based ABA triblock copolymer anion exchange ionomer and membrane (AEI, AEM) materials for anion exchange membrane water electrolysis. Poly(vinylbenzyl N-methylpiperidinium carbonate)-b-polyethylene-b-poly(vinylbenzyl N-methylpiperidinium carbonate) was synthesized with different hydrophobic/hydrophilic block ratios (1.02:1, 2.58:1, and 4.46:1) resulting in a range of ion exchange capacities (1.1–1.8 meq g^–1) and water swelling (23–154%) characteristics. All AEMsmore » showed full anionic dissociation, as evidenced by linear Arrhenius correlations, and excellent carbonate conductivity of 8–94 mS cm^–1 at 50 °C. Hydrophilic phase separation may offer superior chemical durability by only wetting the ion-conducting region of the polymer and avoiding attack at the nonwetted backbone. We evaluated the performance and durability of these AEMs as a function of hydrophobic polyethylene (PE) content. The AEM containing the least amount of PE displayed the highest performance of 1 A cm^–2 at 2.3 V but degraded at 40 mV h^–1 before catastrophically failing after <3 h at 0.5 A cm^–2. With greater PE-containing AEMs, the degradation rate was reduced by 3 orders of magnitude with only a 0.2 V increase in voltage. Constant current electrolysis for 50 h resulted in a voltage change of 0.3 mV h^–1 in a single-cell water electrolyzer and 1 M potassium carbonate. In a 600 h test, the voltage change in the final 200 h was impressively low for an experimental film, 58 μV h^–1. Postmortem analysis indicated that the membrane did not thin and that water becomes more tightly hydrogen-bound in the polymer after electrolysis.« less

Integration of petrophysical and geological information is critical to simulation of subsurface carbon storage (GCS). In this sense, two depositional facies were identified from the core description and well-log interpretation, namely massive (MS) and cross-bedded (CB) facies groups. Additionally, pore-scale characteristics were studied by a combination of techniques, e.g. Nuclear Magnetic Resonance (NMR) and mercury intrusion capillary pressure (MICP). Scanning electron microscope (SEM) and petrographic analyses show that the pore structure is dominantly controlled by the depositional environment and dolomite cementation. NMR-T₂ distributions of MS and CB facies show triple and quadruple modes, respectively. In addition, MICP of high- andmore » low-permeability MS facies samples, and their CB facies group mixtures were collected. The MS sample pore-throat size distribution is uni-modal, while the triple-modal characteristic of the mixtures indicates heterogeneous pore structures at the sub-core scale for CB facies. The reliably estimates of porosity and permeability for both facies groups via NMR techniques and the MLR (Multiple Linear Regression) approach demonstrate the applicability of these techniques to eolian sandstone. Moreover, irreducible water saturation via the T₂-cutoff method correlates strongly with T_2LM instead of porosity. Finally, the rock quality index and flow zone indicator were calculated based on Combinable Magnetic Resonance (CMR) log interpretations. This provides direct connection to properties measured in the well. Four flow units were classified for both facies groups. Finally, results show that better reservoir quality with significant heterogeneities is observed in the CB facies. This study highlights the importance integrating multiscale petrophysical properties including facies, pore architecture and diagenesis analysis with core- to log-scale property characterization. The results herein validate our reservoir characterization and flow unit classification in eolian reservoirs.« less

A depletion solver has been implemented in OpenMC and is described herein. The depletion solver is implemented in Python and interfaces with OpenMC’s transport solver through a C++ application programming interface, which enables an in-memory transport-depletion coupling. Multiple integration methods for advancing in time have been implemented and exhibit tradeoffs in cost, accuracy, and memory use. For all time integration methods, evaluation of the matrix exponential is performed by using the incomplete partial fraction form of the Chebyshev rational approximation method. Simulations of a pressurized water reactor (PWR) pincell and a sodium-cooled fast reactor (SFR) assembly were carried out withmore » OpenMC and Serpent. For both problems, the use of a high-fidelity depletion chain results in predictions of k_eff that agree within 20–30 pcm between OpenMC and Serpent. Predicted actinide concentrations were found to agree to a fraction of a percent, and most fission product concentrations were found to agree within 1%. Here, the few cases where larger differences were observed can be attributed either to differences in how the energy dependence of fission product yields is handled or deficiencies in the nuclear data used. OpenMC simulations of the PWR and SFR problems using a simplified 228-nuclide depletion chain demonstrate that it achieves accuracy close to that of the full, high-fidelity depletion chain with respect to the studied responses.« less

Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss $$\xi $$ and the four-momentum transfer squared t. Both processes $${\text{ p }{}{}} {\text{ p }{}{}} \rightarrow {\text{ p }{}{}} {\text{ X }} $$ and $${\text{ p }{}{}} {\text{ p }{}{}} \rightarrow {\text{ X }} {\text{ p }{}{}} $$, i.e. with the proton scattering to either side of the interaction point, are measured, where $${\text{ X }} $$ includes at least two jets; the results of the two processes are averaged. The analyses are based on datamore » collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at $$\sqrt{s} = 8\,\text {Te}\text {V} $$ during a dedicated run with $$\beta ^{*} = 90\,\text {m} $$ at low instantaneous luminosity and correspond to an integrated luminosity of $$37.5{\,\text {nb}^{-1}} $$. The single-diffractive dijet cross section $$\sigma ^{{\text{ p }{}{}} {\text{ X }}}_{\mathrm {jj}}$$, in the kinematic region $$\xi < 0.1$$, $$0.03< |t | < 1\,\text {Ge}\text {V} ^2$$, with at least two jets with transverse momentum $$p_{\mathrm {T}} > 40\,\text {Ge}\text {V} $$, and pseudorapidity $$|\eta | < 4.4$$, is $$21.7 \pm 0.9\,\text {(stat)} \,^{+3.0}_{-3.3}\,\text {(syst)} \pm 0.9\,\text {(lumi)} \,\text {nb} $$. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of $$\xi $$, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range $$-2.9 \le \log _{10} x \le -1.6$$, is $$R = (\sigma ^{{\text{ p }{}{}} {\text{ X }}}_{\mathrm {jj}}/\Delta \xi )/\sigma _{\mathrm {jj}} = 0.025 \pm 0.001\,\text {(stat)} \pm 0.003\,\text {(syst)} $$, where $$\sigma ^{{\text{ p }{}{}} {\text{ X }}}_{\mathrm {jj}}$$ and $$\sigma _{\mathrm {jj}}$$ are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons.« less

Central exclusive and semiexclusive production of pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, whereas the absence of other particles is ensured by calorimeter information. The total and differential cross sections of exclusive and semiexclusive central production are measured as functions of invariant mass, transverse momentum, andmore » rapidity of the system in the fiducial region defined as transverse momentum and pseudorapidity . The production cross sections for the four resonant channels [inline-graphic not available: see fulltext], , [inline-graphic not available: see fulltext], and [inline-graphic not available: see fulltext]are extracted using a simple model. These results represent the first measurement of this process at the LHC collision energies of 5.02 and 13TeV.« less

Anisotropies in the initial energy density distribution of the quark-gluon plasma created in high energy heavy ion collisions lead to anisotropies in the azimuthal distributions of the final-state particles known as collective anisotropic flow. Fourier harmonic decomposition is used to quantify these anisotropies. The higher-order harmonics can be induced by the same order anisotropies (linear response) or by the combined influence of several lower order anisotropies (nonlinear response) in the initial state. The mixed higher-order anisotropic flow and nonlinear response coefficients of charged particles are measured as functions of transverse momentum and centrality in $$\mathrm {PbPb}$$ collisions at nucleon-nucleon center-of-massmore » energies $$\sqrt{\smash [b]{s_{_{\mathrm {NN}}}}} = 2.76$$ and 5.02$$\,\text {TeV}$$ with the CMS detector. The results are compared with viscous hydrodynamic calculations using several different initial conditions, as well as microscopic transport model calculations. None of the models provides a simultaneous description of the mixed higher-order flow harmonics and nonlinear response coefficients.« less

Measurements are presented of the reduction of signal output due to radiation damage for two types of plastic scintillator tiles used in the hadron endcap (HE) calorimeter of the CMS detector. The tiles were exposed to particles produced in proton-proton (pp) collisions at the CERN LHC with a center-of-mass energy of 13 TeV, corresponding to a delivered luminosity of 50 fb−1. The measurements are based on readout channels of the HE that were instrumented with silicon photomultipliers, and are derived using data from several sources: a laser calibration system, a movable radioactive source, as well as hadrons and muons producedmore » in pp collisions. Results from several irradiation campaigns using 60Co sources are also discussed. The damage is presented as a function of dose rate. Within the range of these measurements, for a fixed dose the damage increases with decreasing dose rate.« less