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Kirkwood–Buff integrals (KBIs) connect the microscopic structure and thermodynamic properties of liquid solutions. KBIs are defined in the grand canonical ensemble and evaluated by assuming the thermodynamic limit (TL). In order to reconcile analytical and numerical approaches, finite-size KBIs have been proposed in the literature, resulting in two strategies to obtain their TL values from computer simulations. (i) The spatial block analysis method in which the simulation box is divided into subdomains of volume V to compute density fluctuations. (ii) A direct integration method where a corrected radial distribution function and a kernel that accounts for the geometry of the integration subvolumes are combined to obtain KBI as a function of V. In this work, we propose a method that connects both strategies into a single framework. We start from the definition of finite-size KBI, including the integration subdomain and an asymptotic correction to the radial distribution function, and solve them in Fourier space where periodic boundary conditions are trivially introduced. The limit q → 0, equivalent to the value of the KBI in the TL, is obtained via the spatial block-analysis method. When compared to the latter, our approach gives nearly identical results for all values of V. Moreover, all finite-size effect contributions (ensemble, finite-integration domains, and periodic boundary conditions) are easily identifiable in the calculation. This feature allows us to analyze finite-size effects independently and extrapolates the results of a single simulation to different box sizes. To validate our approach, we investigate prototypical systems, including SPC/E water and aqueous urea mixtures. [ABSTRACT FROM AUTHOR]

We present a semiclassically approximate quantum treatment of solvation with the purpose of investigating the accuracy of the Caldeira–Leggett model. We do that by simulating the vibrational features of water solvation by means of two different approaches. One is entirely based on the adoption of an accurate ab initio potential to describe water clusters of increasing dimensionality. The other one consists of a model made of a central water molecule coupled to a high-dimensional Caldeira–Leggett harmonic bath. We demonstrate the role of quantum effects in the detection of water solvation and show that the computationally cheap approach based on the Caldeira–Leggett bath is only partially effective. The main conclusion of the study is that quantum methods associated with high-level potential energy surfaces are necessary to correctly study solvation features, while simplified models, even if attractive owing to their reduced computational cost, can provide some useful insights but are not able to come up with a comprehensive description of the solvation phenomenon. [ABSTRACT FROM AUTHOR]

In this paper, we deal with antiferromagnetic (AFM) films using the many-body Green’s function theory under random phase approximation (RPA). This is the first time to be able to calculate all three components of the magnetization of AFM systems simultaneously under RPA. The magnetization of AFM films is not so easily affected by external fields as FM films and the magnetic behavior is rather different from FM films. When an external field Bz is applied along the z direction, the parallel susceptibility χ∥ is zero at 0 K, and then increases with temperature until Néel point TN. If a field along the x-direction Bx is applied, the perpendicular susceptibility can be approximately expressed as χ⊥=1/2γ|J|, which is a temperature-independent constant, where γ is the nearest neighbor and J is the exchange interaction. In this case the z-component magnetization is nonzero above TN. This is because the x-component magnetizations of both sublattices are not zero and the AFM exchange should play a role, which results in the antiparallel z-component magnetizations of the two sublattices. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website. [ABSTRACT FROM AUTHOR]

Pulsed-power generators can produce well-controlled continuous ramp compression of condensed matter for high-pressure equation-of-state studies using the magnetic loading technique. X-ray diffraction (XRD) data from dynamically compressed samples provide direct measurements of the elastic compression of the crystal lattice, onset of plastic flow, strength–strain rate dependence, structural phase transitions, and density of crystal defects, such as dislocations. Here, we present a cost-effective, compact, pulsed x-ray source for XRD measurements on pulsed-power-driven ramp-loaded samples. This combination of magnetically driven ramp compression of materials with a single, short-pulse XRD diagnostic will be a powerful capability for the dynamic materials' community to investigate in situ dynamic phase transitions critical to equation of states. We present results using this new diagnostic to evaluate lattice compression in Zr and Al and to capture signatures of phase transitions in CdS. [ABSTRACT FROM AUTHOR]

We carry out dissipative particle dynamics simulations to investigate the dynamic process of phase transformation in the system with harmonic repulsion particles. Just below the melting point, the system undergoes liquid state, face-centered cubic crystallization, body-centered cubic crystallization, and reentrant melting phase transition upon compression, which is in good agreement with the phase diagram constructed previously via thermodynamic integration. However, when the temperature is decreased sufficiently, the system is trapped into an amorphous and frustrated glass state in the region of intermediate density, where the solid phase and crystal structure should be thermodynamically most stable. [ABSTRACT FROM AUTHOR]

We studied several types of flat lattices with direct exchange and Dzyaloshinskii-Moriya interaction between spins: a honeycomb lattice with 3 nearest neighbours (NN), a square lattice with 4 NN and a hexagonal or triangular lattice with 6 NN. For the analysis of data obtained during the Monte Carlo simulation, a convolutional neural network was used for the recognition of different phases of the spin system which was dependent on simulation parameters such as DMI and external magnetic field (Hz). Based on these data, the phase diagrams (Hz, D) for the different lattices were plotted. The various states of the systems under observation were visualised and the boundaries between the different phases were defined as a spiral, a skyrmion and others. The data from the numerical experiments will be used in further studies to determine the model parameters of the systems for the formation of a stable skyrmion state and the development of methods for controlling skyrmions in a magnetic film. [ABSTRACT FROM AUTHOR]

In a previous study, the behavior of single crystal tantalum under ramp wave loading along the [100] and [110] orientations was characterized. The principal objective of the present study is to gain some insights on the observed single crystal behavior particularly on its precursor response and strong orientation dependence, and the implication of the macroscopic behavior on the possible underlying deformation mechanisms. The approach used to achieve this objective is through the material model development and numerical simulation. A continuum model developed in a previous work for polycrystalline tantalum was first modified to describe the experimental data and extract the material information associated with the data. A rigorous finite deformation single crystal model based on dislocation slip was then developed to gain physical insights into the possible deformation mechanisms. The slip systems considered were the {110}<111> and {112}<111> systems. Dislocation density and its evolution by nucleation or multiplication were incorporated as a key mechanism for describing the precursor behavior in both models. The orientation dependence was modeled through the assumption of anisotropic dislocation nucleation. In the continuum model, different nucleation rates were assumed for the [100] and [110] orientation. In the single crystal model, this anisotropy is assumed to be associated with the twinning/antitwinning asymmetry of the BCC crystals. The precursor for the [100] orientation is attributed mainly to the slips along the antitwinning direction and that for the [110] is to the slips along the twinning direction. The anisotropic dislocation nucleation leads to the orientation dependence of the rate sensitivity of single crystal Ta and the subsequent deformation behavior. Both models were demonstrated to be able to generate reasonably consistent results and to capture the observed material features. Through the developed models, a reasonable understanding was achieved for the evolution of stress, strain, strain rates, strength, temperature, and stress strain relations for single crystal tantalum under ramp wave loading and the possible correlation between the macroscopic behavior and microscopic deformation mechanisms. [ABSTRACT FROM AUTHOR]

Steric effect for the XeBr* (B, C) formation in the oriented Xe*(3P2, MJ=2)+oriented CF3Br reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orientation in the collision frame. Molecular steric opacity function has been determined as a function of the atomic orbital alignment (LZ′) in the collision frame. The LZ′ selectivity in the molecular steric opacity function is different between the XeBr* (B, C) channels: For the XeBr* (C) channel, the LZ′=0 alignment is favorable at the molecular axis direction and the |LZ′|=1 alignment is favorable at the sideway direction, whereas for the XeBr* (B) channel, the LZ′=0 alignment is favorable at the sideway direction and the |LZ′|=1 alignment is favorable at the molecular axis direction. However, the shape of the steric opacity function for the XeBr* (B) channel at the LZ′=0 (and |LZ′|=1) alignment is similar to that for the XeBr* (C) channel at the |LZ′|=1 (and LZ′=0) alignment, respectively: A large molecular orientation dependence (i.e., the largest reactivity at the Br-end with the small molecular alignment dependence) is recognized for the XeBr* (B) channel at the LZ′=0 alignment and for the XeBr* (C) channel at the |LZ′|=1 alignment, whereas a large molecular alignment dependence (i.e., the largest reactivity at the Br-end with the poor reactivity at the sideway) is recognized for the XeBr* (B) channel at the |LZ′|=1 alignment and for the XeBr* (C) channel at the LZ′=0 alignment. We propose the indirect mechanism for the dark channels (Xe+Br+CF3) via the back-electron transfer from the CF3 segment (or dissociating CF3...Br-) to Xe+ as the origin of the significant molecular alignment dependence in the molecular steric opacity function. [ABSTRACT FROM AUTHOR]

In a previous study by Asay et al. [J. Appl. Phys. 106, 073515 (2009)], the inelastic response of annealed and cold-rolled pure polycrystalline tantalum at intermediate strain rates was characterized with ramp wave loading to peak longitudinal stresses of 17 GPa. It was found that the annealed Ta at strain rates of about 106/s exhibited pronounced elastic overshoot, followed by rapid stress relaxation and the amplitude of the elastic precursor depicted essentially no dependence on sample thickness for samples with controlled initial properties, in contrast to the precursor attenuation typically observed in shock wave experiments. The precursor for the cold-rolled sample was more dispersive and did not exhibit the characteristics depicted by the annealed samples. A principal objective of the present study was to gain some insights into this behavior and its implication on the deformation mechanisms for tantalum. Another objective was to gain a fundamental understanding of the dynamic inelasticity of polycrystalline tantalum, its evolution with the processing history, and the resultant thermomechanical behavior. The approach used to achieve these objectives was to first develop a material model that captured the observed material characteristics and then to use numerical simulations of dynamic experiments to gain additional insights into the observed material behavior. The constitutive model developed is based on the concept of dislocation generation and motion. Despite its simplicity, the model works quite well for both sets of data and serves a valuable tool to achieve the research objectives. The tantalum studied here essentially exhibits a strong rate sensitivity and this behavior is modeled through the low dislocation density and the strong stress dependence of the dislocation velocity. For the annealed material, the mobile dislocation density is assumed to be essentially zero in the model. This low dislocation density combined with strong stress dependence of dislocation velocity results in a metastable elastic response and a precursor that shows little attenuation. The increase of mobile dislocations through the cold-rolling process leads to a less rate-sensitive behavior for the cold-rolled tantalum and also the disappearance of the precursor behavior observed for the annealed samples. Both the low dislocation density and the strong rate dependence of the dislocation velocity may be related to the low mobility of the screw dislocations in bcc metals. This low mobility results from its extended, three-dimensional core structure. [ABSTRACT FROM AUTHOR]

Steric effects for the XeI* (B) and XeI* (C) formations in the oriented Xe* (3P2,MJ=2)+oriented CF3I reaction have been observed as a function of the mutual configuration between molecular orientation and atomic alignment in the collision frame. The mutual configuration exercises the significant influences on the stereoanisotropy for both the reactivity and the branching to the XeI* (B) and XeI* (C) channels. [ABSTRACT FROM AUTHOR]

A pure and highly intense state-selected pulsed supersonic CH(X 2Π) radical beam source was developed by use of the C(1D)+H2 reaction with the combination of the state selection and purification by an electrostatic hexapole field. Under the beam-cell condition, the elementary reactions of CH+NO and CH+O2 were studied by using this state-selected CH beam. NH(A 3Π) [and NCO(A 2Σ+)] formations and OH(A 2Σ+) formation were directly identified in the elementary reaction of CH+NO and CH+O2, respectively. For the CH+NO reaction, the relative branching ratio σNCO*/σNH of NCO(A 2Σ+) formation to NH(A 3Π) formation was determined to be 0.35±0.15. The state-selected reaction cross sections were determined for each rotational state of CH. In the CH+NO reaction, a remarkable rotational state dependence of the reactive cross section was revealed, while the CH+O2 reaction showed little rotational state dependence. [ABSTRACT FROM AUTHOR]

The collision energy and orientation-angle-resolved Penning ionization cross sections were determined for the Ar ([sup 3]P)+CH[sub 3]I reaction. A remarkable depletion was recognized in the collision- energy dependence of the orientation-angle-resolved Penning ionization cross section. The depletion could be interpreted as the competitive neutral dissociation from the Rydberg states formed by an electron exchange mechanism related to a 3a[sub 1] molecular orbital. The stereo selectivity for the Penning ionization and neutral dissociation were discussed. From the series of our studies on Ar ([sup 3]P)+CH[sub 3]X (X=Cl,Br,I) reactions, it was substantiated that the orientation angle and collision-energy-resolved Penning ionization cross section give an important information about the branching mechanism to the Rydberg states that are linked to the neutral dissociation channels. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The article presents information on the patent application 7,467,687 for thermal-acoustic enclosure, assigned to General Electric Co. The patent proposes an enclosure for a noisy machine. It has an inner panel, another outer panel and a frame that supports the panels through a vibration isolation mounting.

In this article, we investigate the emergence of tissue dynamics with time delays of diffusion. Such emergent dynamics, describing the tissue homeostasis, usually correspond to particular tissue functions, which are attracting a tremendous amount of attention from both communities of mathematical modeling and systems biology. Specifically, in addition to the within-cell genome dynamics and the diffusion among the cells, we consider several types of time delays of diffusion present in the coordinated cells. We establish several generalized versions of the "monotonicity condition" (MC), whose traditional version [I. Rajapakse and S. Smale, Proc. Natl. Acad. Sci. U.S.A. 114, 1462–1467 (2017)] guaranteed the stability of the equilibrium in a system of coordinated cells without time delay. Indeed, we find that one generalized MC we establish still guarantees the stability of the time-delayed system's equilibrium, which corresponds to a formation of tissue functions depending primarily on individual genome dynamics but less on interacting structures and time delays of diffusion. We also find that, when the generalized MC is further relaxed, the system is able to sustain periodic oscillations, whose periods are verified to have delicate dependence with the selected time delays. These produced oscillations usually represent realistic behaviors of "alive" cells. We use several representative examples to demonstrate the usefulness of the established analytical conditions to the understanding of the emergent dynamics observed in computational models and in real systems as well. [ABSTRACT FROM AUTHOR]

Examines the temperature dependence of the quenching efficiency of Mg(3s3p [sup 1]P[sub 1]) by methane collision in the argon bath gas. Use of the pump-probe technique with laser-induced fluorescence; Validity of orbiting and absorbing-sphere models to the current system; Implication of negative temperature dependence for the depth-well energy intermediate.

Experiments have been performed at ASDEX Upgrade, aiming to investigate the impact of lithium in an all-metal-wall tokamak and attempting to enhance the pedestal operational space. For this purpose, a lithium pellet injector has been developed, capable of injecting pellets carrying a particle content ranging from 1.82 × 1019 atoms (0.21 mg) to 1.64 × 1020 atoms (1.89 mg). The maximum repetition rate is about 2 Hz. Free flight launch from the torus outboard side without a guiding tube was realized. In such a configuration, angular dispersion and speed scatter are low, and a transfer efficiency exceeding 90% was achieved in the test bed. Pellets are accelerated in a gas gun; hence special care was taken to avoid deleterious effects by the propellant gas pulse. Therefore, the main plasma gas species was applied as propellant gas, leading to speeds ranging from 420 m/s to 700 m/s. In order to minimize the residual amount of gas to be introduced into the plasma vessel, a large expansion volume equipped with a cryopump was added into the flight path. In view of the experiments, an optimal propellant gas pressure of 50 bars was chosen for operation, since at this pressure maximum efficiency and low propellant gas flux coincide. This led to pellet speeds of 585m/s '± 32m/s. Lithium injection has been achieved at ASDEX Upgrade, showing deep pellet penetration into the plasma, though pedestal broadening has not been observed yet. [ABSTRACT FROM AUTHOR]

We develop a model of a current sheet including field-aligned currents and a finite value of the normal component of magnetic field. The model is based on the conservation of a quasiadiabatic invariant of ion motion, while for electrons a fluid approach is used. A part of the current becomes parallel to the magnetic field due to the magnetic field shear, however the perpendicular component of the current is also present. The difference in the plasma pressure between the current sheet center and its boundaries decreases is only half of the value of the model free of parallel currents. We discuss the possible application of the model developed in this paper. [ABSTRACT FROM AUTHOR]

Veloce is a medium-voltage, high-current, compact pulsed power generator developed for isentropic and shock compression experiments. Because of its increased availability and ease of operation, Veloce is well suited for studying isentropic compression experiments (ICE) in much greater detail than previously allowed with larger pulsed power machines such as the Z accelerator. Since the compact pulsed power technology used for dynamic material experiments has not been previously used, it is necessary to examine several key issues to ensure that accurate results are obtained. In the present experiments, issues such as panel and sample preparation, uniformity of loading, and edge effects were extensively examined. In addition, magnetohydrodynamic simulations using the ALEGRA code were performed to interpret the experimental results and to design improved sample/panel configurations. Examples of recent ICE studies on aluminum are presented. [ABSTRACT FROM AUTHOR]

One of the major applications of the dielectrophoresis is selective trapping and fractionation in lab-on-a-chip devices. Nevertheless, many-particles effects due to high concentration of biological material around electrodes can cause a rapid decrease in trapping efficiency in dielectrophoretic devices. In this paper we present an approach based on a drift-diffusion dynamics to study the particles behavior near electrodes surroundings. Within this approach, we introduce many-particles effects by invoking the effective medium approximation, electrodes can saturate losing their capability to attract further particles and thus leading to a more realistic scenario never shown in past literature. [ABSTRACT FROM AUTHOR]

The article presents information on the patent application 7,467,542 assigned to Palo Alto Research Center Inc. The patent describes a system for implementing atomic force microscopy in liquids utilizing a radiation pressure-driven cantilever. The system is designed to overcome very high losses involved in oscillating a typical atomic force microscope cantilever in water.

The article presents information on the patent application 7,467,498 related to flexible sheet materials for tensioned structures. The patent, which is assigned to Newmat SA, discusses the absorptive properties of a thin micro-perforated, tensioned vinyl and how well it works.

The article presents information on the patent application 7,464,790 related to sound insulation/absorption structure. The patent proposes a structure which comprises a frame, surface layers of polymer film or metal foil, and absorptive filler between the layers.

The article presents information on the patent application 7,467,688 for multi-composite acoustic panel assigned to Royal Mat Co. The patent proposes some methods for an impact isolation panel using particles of wood fibers from sawdust, crumbs of rubber, and a polyurethane or elastomeric binder.

The article presents information on the patent application 7,467,022 which proposes a method for fabricating a hearing aid shell and mold with test fitting by the user. In this method, a three-dimensional model of a custom hearing aid shell is developed which is used to determine whether the hearing aid components will fit.

The article evaluates several acoustical patents including untegrated mapping and audio systems, sonars and signal processors.

Natural frequencies are determined for the transverse vibrations of a circular plate that is simply supported by a concentric ring of arbitrary radius. Frequency coefficients are plotted for modes having 0, 1, 2, or 3 nodal diameters and 0, 1. 2, or 3 nodal circles. Comparison is made with similar vibrations of the fixed center plate, the free-edge plate, and the plate simply supported at the edge. [ABSTRACT FROM AUTHOR]