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B L Smorodin, I N Cherepanov, S N Ishutov, B I Myznikova
The results of a theoretical study are presented dealing with convective heat and mass transfer in a colloidal suspension through a Hele-Shaw cell heated from below. The numerical analysis, based on a multi-component model, reveals that for a certain range of parameter values the dynamical regimes of travelling waves as well as oscillatory fingering formation are stable. The bifurcation phenomena and nonlinear evolution of spatiotemporal patterns that develop in the colloid suspension are modeled and discussed, paying special attention to the combined effects of gravity sedimentation, thermal diffusion with positive separation ratio and convection...
February 2017: European Physical Journal. E, Soft Matter
N Ratan, N J Sircombe, L Ceurvorst, J Sadler, M F Kasim, J Holloway, M C Levy, R Trines, R Bingham, P A Norreys
Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.
January 2017: Physical Review. E
Daniel E Bugaris, Christos D Malliakas, Fei Han, Nicholas P Calta, Mihai Sturza, Matthew Krogstad, Raymond Osborn, Stephan Rosenkranz, Jacob P C Ruff, Giancarlo Trimarchi, Sergey L Bud'ko, Mahalingam Balasubramanian, Duck Young Chung, Mercouri G Kanatzidis
A new polymorph of the RE2Ru3Ge5 (RE = Pr, Sm, Dy) compounds has been grown as single crystals via an indium flux. These compounds crystallize in tetragonal space group P4/mnc with the Sc2Fe3Si5-type structure, having lattice parameters a = 11.020(2) Å and c = 5.853(1) Å for RE = Pr, a = 10.982(2) Å and c = 5.777(1) Å for RE = Sm, and a = 10.927(2) Å and c = 5.697(1) Å for RE = Dy. These materials exhibit a structural transition at low temperature that occurs due to the charge density wave (CDW). Both the high-temperature average crystal structure and the low-temperature incommensurately modulated crystal structure (for Sm2Ru3Ge5 as a representative) have been solved...
February 16, 2017: Journal of the American Chemical Society
Thomas P Albright, Denis Mutiibwa, Alexander R Gerson, Eric Krabbe Smith, William A Talbot, Jacqueline J O'Neill, Andrew E McKechnie, Blair O Wolf
Extreme high environmental temperatures produce a variety of consequences for wildlife, including mass die-offs. Heat waves are increasing in frequency, intensity, and extent, and are projected to increase further under climate change. However, the spatial and temporal dynamics of die-off risk are poorly understood. Here, we examine the effects of heat waves on evaporative water loss (EWL) and survival in five desert passerine birds across the southwestern United States using a combination of physiological data, mechanistically informed models, and hourly geospatial temperature data...
February 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yunkyu Bang, G R Stewart
Although the pairing mechanism of Fe-based superconductors (FeSCs) has not yet been settled with consensus with regard to the pairing symmetry and the superconducting (SC) gap function, the vast majority of experiments support the existence of spin-singlet sign-changing s-wave SC gaps on multi-bands ([Formula: see text]-wave state). This multi-band [Formula: see text]-wave state is a very unique gap state per se and displays numerous unexpected novel SC properties, such as a strong reduction of the coherence peak, non-trivial impurity effects, nodal-gap-like nuclear magnetic resonance signals, various Volovik effects in the specific heat (SH) and thermal conductivity, and anomalous scaling behaviors with a SH jump and condensation energy versus T c, etc...
February 13, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Takashi Sakurai
The solar corona is a tenuous outer atmosphere of the Sun. Its million-degree temperature was discovered spectroscopically in the 1940s, but its origin has been debated since then without complete convergence. Currently there are two classes of models; the wave theory and the microflare/nanoflare theory. Both models have merits and disadvantages, but the essential issues are nearly pinned down. Recent revival of the wave theory is one of the many contributions from Japanese solar observing satellite Hinode launched in 2006...
2017: Proceedings of the Japan Academy. Series B, Physical and Biological Sciences
T P Lyubimova, E S Sadilov, S A Prokopev
The paper deals with the investigation of the onset and weakly nonlinear regimes of the Soret-driven convection of ternary liquid mixture in a horizontal layer with rigid impermeable boundaries subjected to the prescribed constant vertical heat flux. It is found that there are monotonous and oscillatory longwave instability modes. The boundary of the monotonous longwave instability in the parameter plane Rayleigh number Ra - net separation ratio [Formula: see text] at fixed separation ratio of one of solutes consists of two branches of hyperbolic type...
February 2017: European Physical Journal. E, Soft Matter
Iqra Shahzadi, Hina Sadaf, Sohail Nadeem, Anber Saleem
OBJECTIVE: The main objective of this paper is to study the Bio-mathematical analysis for the peristaltic flow of single wall carbon nanotubes under the impact of variable viscosity and wall properties. DESIGN/APPROACH: The right and the left walls of the curved channel possess sinusoidal wave that is travelling along the outer boundary. The features of the peristaltic motion are determined by using long wavelength and low Reynolds number approximation. Exact solutions are determined for the axial velocity and for the temperature profile...
February 2017: Computer Methods and Programs in Biomedicine
Rui Li, Shuang Zhang, Xiaoxi Kou, Bo Ling, Shaojin Wang
To develop advanced pasteurization treatments based on radio frequency (RF) or microwave (MW) energy, dielectric properties of almond kernels were measured by using an open-ended coaxial-line probe and impedance analyzer at frequencies between 10 and 3000 MHz, moisture contents between 4.2% to 19.6% w.b. and temperatures between 20 and 90 °C. The results showed that both dielectric constant and loss factor of the almond kernels decreased sharply with increasing frequency over the RF range (10-300 MHz), but gradually over the measured MW range (300-3000 MHz)...
February 10, 2017: Scientific Reports
S Rocha, C Kerdelhué, M L Ben Jamaa, S Dhahri, C Burban, M Branco
Extreme climate events such as heat waves are predicted to become more frequent with climate change, representing a challenge for many organisms. The pine processionary moth Thaumetopoea pityocampa is a Mediterranean pine defoliator, which typically lays eggs during the summer. We evaluated the effects of heat waves on egg mortality of three populations with different phenologies: a Portuguese population with a classical life cycle (eggs laid in summer), an allochronic Portuguese population reproducing in spring, and a Tunisian population from the extreme southern limit of T...
February 10, 2017: Bulletin of Entomological Research
Martin Kreuzer, Laura Sollmann, Stephan Ruben, Maren Leifheit-Nestler, Dagmar-Christiane Fischer, Lars Pape, Dieter Haffner
BACKGROUND: Shiga-toxin-producing Escherichia coli (STEC)-associated hemolytic-uremic syndrome (HUS) is a major cause of acute kidney injury (AKI), especially in children. Its long-term outcome with respect to endothelial damage remains largely elusive. METHODS: This was a cross-sectional study in 26 children who had suffered from STEC-HUS in the past and achieved a complete recovery of renal function (eGFR >90 ml/min/1.73 m(2)). Skin microcirculation after local heating was assessed by laser Doppler fluximetry, carotid-femoral pulse wave velocity (PWV), carotid intima media thickness (cIMT), 24-h ambulatory blood pressure, and angiopoietin (Ang) 1 and 2 serum levels after a median follow-up period of 6...
February 8, 2017: Pediatric Nephrology: Journal of the International Pediatric Nephrology Association
Dominik Florian Stangler, Andreas Hamann, Hans-Peter Kahle, Heinrich Spiecker, Annikki Mäkelä
No abstract text is available yet for this article.
January 31, 2017: Tree Physiology
Margot Pasternak, Eigil Samset, Jan D'hooge, Geir U Haugen
Ultrasound thermometry is based on measuring tissue temperature by its impact on ultrasound wave propagation. This study focuses on the use of transducer array channel data (not beamformed) and examines how a layer of increased velocity (heat induced) affects the travel-times of the ultrasound backscatter signal. Based on geometric considerations, a new equation was derived for the change in time delay as a function of temperature change. The resulting expression provides insight into the key factors that link change in temperature to change in travel time...
January 16, 2017: Ultrasonics
Meisam Kashcooli, Mohammad Reza Salimpour, Ebrahim Shirani
Specifying exact geometry of vessel network and its effect on temperature distribution in living tissues is one of the most complicated problems of the bioheat field. In this paper, the effects of blood vessels on temperature distribution in a skin tissue subjected to various thermal therapy conditions are investigated. Present model consists of counter-current multilevel vessel network embedded in a three-dimensional triple-layered skin structure. Branching angles of vessels are calculated using the physiological principle of minimum work...
February 2017: Journal of Thermal Biology
Ryota Morimoto, Akimasa Hirata, Ilkka Laakso, Marvin C Ziskin, Kenneth R Foster
This study computes the time constants of the temperature elevations in human head and body models exposed to simulated radiation from dipole antennas, electromagnetic beams, and plane waves. The frequency range considered is from 1 to 30 GHz. The specific absorption rate distributions in the human models are first computed using the finite-difference time-domain method for the electromagnetics. The temperature elevation is then calculated by solving the bioheat transfer equation. The computational results show that the thermal time constants (defined as the time required to reach 63% of the steady state temperature elevation) decrease with the elevation in radiation frequency...
March 7, 2017: Physics in Medicine and Biology
Dominik Florian Stangler, Andreas Hamann, Hans-Peter Kahle, Heinrich Spiecker
No abstract text is available yet for this article.
January 31, 2017: Tree Physiology
Mohammad Sabaeian, Hamidreza Rezaei, Abdolmohammad Ghalambor-Dezfouli
Pulsed laser beam excitations are more commonly used in thermal lens spectroscopy (TLS) than continuous-wave (CW) ones, because CW excitations limit the measurement to linear absorption processes [J. Opt. A5, 256 (2003)]. In this work, we present a new and full analytical model for a single-pulsed laser excitation dual-beam mode-mismatched TLS for low absorption solid-state and liquid samples. Our model has been based on a new solution of time-dependent heat equation for a finite-radius cylindrical sample exposed to a single-pulsed excitation laser beam...
February 1, 2017: Applied Optics
Yan Zhou, Jianqiu Xu, Yulong Tang
We report a multiple-gain-element Nd:YAG laser where the gain media (three pieces of slab crystal) are alternately bonded to two optical quality 4H-SiC wafers. Such composite gain configuration can efficiently remove waste heat from the gain medium, preventing thermal lensing and heat-induced birefringence/distortion under high power laser operation. Through near Brewster's angles incidence designing and polarization discrimination, two orthogonally linearly polarized (P and S polarized) laser beams are generated simultaneously from different parts of the same system...
January 23, 2017: Optics Express
A Diebold, Z Jia, I J Graumann, Y Yin, F Emaury, C J Saraceno, X Tao, U Keller
We present the first demonstration of a thin-disk laser based on the gain material Yb:GGG. This material has many desirable properties for the thin-disk geometry: a high thermal conductivity, which is nearly independent of the doping concentration, a low quantum defect, low-temperature growth, and a broadband absorption spectrum, making it a promising contender to the well-established Yb:YAG for high-power applications. In continuous wave laser operation, we demonstrate output powers above 50 W, which is an order of magnitude higher than previously achieved with this material in the bulk geometry...
January 23, 2017: Optics Express
Dong Liu, Christopher L Brace
Tissue contraction plays an important role during high temperature tumor ablation, particularly during device characterization, treatment planning and imaging follow up. We measured such contraction in 18 ex vivo bovine liver samples during microwave ablation by tracking fiducial motion on CT imaging. Contraction was then described using a thermal dose dependent model and a negative thermal expansion coefficient based on the empirical data. FEM simulations with integrated electromagnetic wave propagation, heat transfer, and structural mechanics were evaluated using temperature-dependent dielectric properties and the negative thermal expansion models...
February 2, 2017: Physics in Medicine and Biology
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