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Full-Text Articles in Physical Sciences and Mathematics

Finite-Temperature Properties Of Strongly Correlated Fermions In The Honeycomb Lattice, Baoming Tang, Thereza Paiva, Ehsan Khatami, Marchos Rigol Sep 2013

Finite-Temperature Properties Of Strongly Correlated Fermions In The Honeycomb Lattice, Baoming Tang, Thereza Paiva, Ehsan Khatami, Marchos Rigol

Ehsan Khatami

We study finite-temperature properties of strongly interacting fermions in the honeycomb lattice using numerical linked-cluster expansions and determinantal quantum Monte Carlo simulations. We analyze a number of thermodynamic quantities, including the entropy, the specific heat, uniform and staggered spin susceptibilities, short-range spin correlations, and the double occupancy at and away from half filling. We examine the viability of adiabatic cooling by increasing the interaction strength for homogeneous as well as for trapped systems. For the homogeneous case, this process is found to be more efficient at finite doping than at half filling. That, in turn, leads to an efficient adiabatic …


Cyclic Heating To Inhibit Bacterial Growth In Activated Carbon Point-Of-Use Treatment Devices, Irwin Silverstein, Irvine W. Wei Aug 2013

Cyclic Heating To Inhibit Bacterial Growth In Activated Carbon Point-Of-Use Treatment Devices, Irwin Silverstein, Irvine W. Wei

Irvine W. Wei

The effectiveness of using heat treatment on a cyclic basis as a means of inhibiting bacterial growth in activated carbon point-of-use treatment devices was examined. Heat treated and non-heat treated devices were compared in a controlled experiment with respect to parameters such as standard plate count, total organic carbon, total residual chlorine and head loss. The results of the study indicated that cyclic heat treatment can inhibit bacterial growth on the surface of granular activated carbon without compromising total organic carbon and total residual chlorine removal efficiencies or accelerating head loss. Microbiological testing verified that the control device had become …


Reactions Of Small Carbon-Bearing Radicals With Unsaturated Hydrocarbons: Product Detection And Low Temperature Kinetics, Adam Trevitt, Fabien Goulay, Stephen Leone Jul 2013

Reactions Of Small Carbon-Bearing Radicals With Unsaturated Hydrocarbons: Product Detection And Low Temperature Kinetics, Adam Trevitt, Fabien Goulay, Stephen Leone

Adam Trevitt

We report on results from two experimental techniques concerned with the reactions of small carbon based radicals (CN and CH) with unsaturated hydrocarbons. First, low temperature (100-300K) kinetic studies using a pulse Laval nozzle technique probe the reactions of the CN radical with benzene and toluene. The CN + benzene is found to be a fast, barrierless reaction. But in the case of toluene, two reaction pathways are in competition, one of which back dissociates to the reactants. The implications for the atmosphere of Titan are discussed. Product detection studies undertaken at the Advanced Light Source (ALS) using synchrotron coupled …


Temperature-Dependent Electrical, Elastic And Magnetic Properties Of Solgel Synthesized Bi 0.9ln 0.1feo 3 (Ln=Nd,Sm), J Schiemer, R L Withers, M Carpenter, Y Liu, Jianli Wang, L Noren, Q Li, W Hutchison Jul 2013

Temperature-Dependent Electrical, Elastic And Magnetic Properties Of Solgel Synthesized Bi 0.9ln 0.1feo 3 (Ln=Nd,Sm), J Schiemer, R L Withers, M Carpenter, Y Liu, Jianli Wang, L Noren, Q Li, W Hutchison

Jianli Wang

This report details correlated electrical, mechanical and magnetic behaviour in BiFeO3 ceramics doped with 10% Ln (Ln D Sm, Nd) ions on the Bi, or perovskite A, site and synthesized by a sol-gel method. The ceramics exhibit bulk piezoelectric and ferroelectric properties and clear ferroelectric domain patterns through piezoresponse force microscopy. Resonant ultrasound spectroscopy, dielectric spectroscopy and magnetometry studies show correlated magnetoelectromechanical behaviour and the existence of weak ferromagnetism for both compositions. An anomaly with simultaneous mechanical and magnetic signatures is discovered in both materials near room temperature, while previously reported transitions and anomalies are found to exhibit electro- and/or …


Observations Of Mesospheric Temperature Variability Over The Andes, Jonathan R. Pugmire, Michael J. Taylor, Yucheng Zhao, P Dominique Pautet, James M. Russell Iii Jun 2013

Observations Of Mesospheric Temperature Variability Over The Andes, Jonathan R. Pugmire, Michael J. Taylor, Yucheng Zhao, P Dominique Pautet, James M. Russell Iii

Jonathan Pugmire

Observations of mesospheric OH(6,2) rotational temperatures by the Utah State University Mesospheric Temperature Mapper (MTM) located at the Andes Lidar Observatory, Cerro Pachon, Chile (30.3°S, 70.7°S) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. This study investigates MTM temperature variability over the past 3.5 years comprising over 700 nights of high-quality data and compares the results with Maui-MALT, Hawaii MTM (2001-2005) measurements and coincident mesospheric temperature measurement by SABER on the NASA TIMED satellite.


The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou Jun 2013

The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou

Shi Xue Dou

No abstract provided.


Comparison Of Small-Field Behaviour In Mgb2, Low And High Temperature Superconductors, Alexey V. Pan, S X. Dou Jun 2013

Comparison Of Small-Field Behaviour In Mgb2, Low And High Temperature Superconductors, Alexey V. Pan, S X. Dou

Shi Xue Dou

Different types of superconductors have been investigated at small magnetic fields (Ba) over wide temperature (T) ranges at different Ba orientations. It has been shown that the temperature dependence of the characteristic field (B*), separating the Ba-independent critical current density (Jc) plateau (single vortex pinning regime) and the region with Jc(Ba) (collective pinning), can be attributed either to the temperature dependence of the magnetic penetration depth for Nb-film and MgB2bulk superconductors, or to thermally activated processes for Bi-based superconductors and YBa2Cu3O7−δ superconducting films. In both cases the vortex pinning influence appears to have a secondary role, affecting the effective vortex …


Reduction Of Superconducting Transition Temperature And Flux Pinning In Al And C Codoped Mgb2 With Insight From First-Principles Calculations, Aihua Li, Xiaolin Wang, S X. Dou, Qiwen Yao, Zhenxiang Cheng, Saeid Soltanian, J M. Yoo, P Munroe Jun 2013

Reduction Of Superconducting Transition Temperature And Flux Pinning In Al And C Codoped Mgb2 With Insight From First-Principles Calculations, Aihua Li, Xiaolin Wang, S X. Dou, Qiwen Yao, Zhenxiang Cheng, Saeid Soltanian, J M. Yoo, P Munroe

Shi Xue Dou

We report for the first time the Al and C codoping effect on the structures and superconductivity in MgB2. It was found that both the lattice parameters and the Tc decreased monotonically with increasing doping level of both Al and C. The Tc dropped to 27.5 and 7 K for x=0.2 and for x =0.4, respectively. The reduction of Tc for the codoping was found to be quicker than for individual Al doping and slower than for individual C doping at the same doping levels. First-principles calculations indicated that the observed decrease in Tc …


Room Temperature Giant And Linear Magnetoresistance In Topological Insulator Bi2te3 Nanosheets, Xiaolin Wang, Yi Du, S X. Dou, Chao Zang Jun 2013

Room Temperature Giant And Linear Magnetoresistance In Topological Insulator Bi2te3 Nanosheets, Xiaolin Wang, Yi Du, S X. Dou, Chao Zang

Shi Xue Dou

"Topological insulators, a new class of condensed matter having bulk insulating states and gapless metallic surface states, have demonstrated fascinating quantum effects. However, the potential practical applications of the topological insulators are still under exploration worldwide. We demonstrate that nanosheets of a Bi2Te3 topological insulator several quintuple layers thick display giant and linear magnetoresistance. The giant and linear magnetoresistance achieved is as high as over 600% at room temperature, with a trend towards further increase at higher temperatures, as well as being weakly temperature-dependent and linear with the field, without any sign of saturation at measured fields up to 13 …


Investigating Mesospheric Gravity Wave Dynamics And Temperature Variability Over The Andes, Jonathan R. Pugmire, Michael J. Taylor Apr 2013

Investigating Mesospheric Gravity Wave Dynamics And Temperature Variability Over The Andes, Jonathan R. Pugmire, Michael J. Taylor

Jonathan Pugmire

Observations of mesospheric OH(6,2) temperatures by the Utah State University Mesospheric Temperature Mapper located at Cerro Pachon, Chile (30.3°S, 70.7°S) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. Comparative studies with other data sets including the satellite-borne SABER instrument show good agreement on nightly, as well as seasonal, temperature measurements.


Variation Of Hyporheic Temperature Profiles In A Low Gradient Third-Order Agricultural Stream – A Statistical Approach, Vanessa Beach, Eric Wade Peterson Dec 2012

Variation Of Hyporheic Temperature Profiles In A Low Gradient Third-Order Agricultural Stream – A Statistical Approach, Vanessa Beach, Eric Wade Peterson

Eric Wade Peterson

Sediment size governs advection, controlling the hydraulic conductivity of the stratum, and conduction, influencing the amount of surface area in contact between the sediment particles. To understand the role of sediment particle size on thermal profiles within the hyporheic zone, a statistical approach, involving general summary statistics and time series cross-correlation, was employed. Data were collected along two riffles: Site 1: gravel (d50 = 3.9 mm) and Site 2: sand (d50 = 0.94 mm).Temperature probe grids collected 15-minute temperature data at 30, 60, 90, and 140 cm below the streambed surface over a 6-month period. Surface water and air temperature …