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This article aims to numerically compute the magnetic induced flow in the framework of higher order continuum through its implementation using FreeFem++. The flow through a rectangular channel is assumed laminar, incompressible and under constant applied pressure. External magnetic field is applied through the boundary of the channel. To compute the physical response theory of micropolar continuum is taken into consideration and governing dynamics is described in the form of coupled partial differential equations in velocity, induction and microrotation field variables along with associated boundary conditions. Sparse linear system is thus obtained with the application of finite element method. The resulting system is then solved by sparse solver available in unsymmetric multifrontal package (UMFPACK) through FreeFem++. The variational form of the model is presented and implemented in FreeFem++. Pertinent to physical significance different parameters i.e., magnetic Reynolds number, Hartmann number, micropolar coupling constant, micropolar parameter are studied and results are shown through simulations and graphs.It is observed that with an increase in micropolar coupling parameter the magnetic induction as well as the microrotational velocity of particles decreases in the medium. The maximum magnitude of microrotational velocities is observed near walls of the channel. The microrotational spin in the channel flow slows down due to an increase in induced magnetic field. Moreover, it is found that direct solver for the asymmetric sparse linear system arise in this case does not lead to stable solution. This instability in the solution arises when the Hartmann number in simulations increases than a value of 1.5. Therefore, iterative solver based on generalized minimal residual method (GMRES) should be adopted to weed out the instabilities due to fine scale oscillations of translational as well as microrotational motions of the fluid particles in case of large Hartmann number. [ABSTRACT FROM AUTHOR]

This paper explores thermal quantum memory-assisted entropic uncertainty, Bell-non-locality, and entanglement in a two-qubit Heisenberg XXX chain with x -directional Dzyaloshinskii-Moriya (DM) and Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) interactions in thermal equilibrium. We find this crucial that the initial degree of nonlocality and entanglement in the two-qubit state entirely depends upon the temperature, orientation, and strength of the DM and KSEA interaction of the magnetic field. Among many other situations, the magnetic field characterized by DM interaction with minimal temperature, exchange coupling strength, and KSEA interaction is the most reliable for generating and maintaining maximal nonlocality and entanglement while completely suppressing entropic uncertainty. On the other hand, repeated revivals and non-Markovian dynamics have been observed when the magnetic field is characterized by exchange coupling constant, DM and KSEA interaction with a higher temperature limit. Except for temperature-based magnetic fields, we show that maximal entanglement and nonlocality are generated and preserved in the two qubits with zero-order entropic uncertainty, which we believe is a better result than previous studies. [ABSTRACT FROM AUTHOR]

Parabolic carrier Pulse Width Modulation (PWM) method is considered as one of the direct current control methods for the Voltage Source Converters (VSCs). This method has an excellent dynamic response. Besides, it offers a constant switching frequency by employing a pair of parabolic PWM carriers. However, it suffers from some drawbacks and limitations. The major drawback of this method is its sensitivity to the inductance variations. In other words, in grid-connected applications, the exact value of grid inductance should be known to achieve a proper performance. Moreover, it is essential that during each switching cycle, the voltage at the point of common coupling remains constant. In grid connected applications such as active power filter, these drawbacks may lead to operation at variable or non-expected frequencies. Therefore, this paper provides suggestions to deal with the situation. In this paper, by applying the conventional method, the aforementioned problems are examined in a grid-connected active power filter. It is shown analytically that by using the proposed method, the problem of sensitivity to inductance is overcome and the necessity for a constant voltage at the point of common coupling in a switching period will be solved as well. The simulation and experimental results are presented. [ABSTRACT FROM AUTHOR]

The inductive coupling link technique is popularly used for transmitting power in many biomedical applications, where it helps in transferring power to numerous implanted biomedical devices like a wireless pressure sensor system. It has also been noted that the inductive coupling variables significantly affect the coupling efficiency. In this study, the researchers have investigated the inductive coupling link variables for 3 transmitter coils and one receiver coil. They used a resonant frequency of 27 MHz as the operating frequency, based on the Industrial, Scientific and Medical (ISM) band. The experimental results indicated that the Voltage gain (i.e., Vgain) value of the inductive links was dependent on the Coupling Factor (K) existing between every coil and load resistance (i.e., Rload). It was also noted that the value of the Voltage gain increased with an increase in the implanted resistance, based on a constant coupling factor. Furthermore, the simulation results indicated that if the Rload=1000, the Vgain value would be maximal, whereas if Rload = 200Ω, the Vgain value would be minimal and ≈ 5V. These results indicated that the operating system could satisfy all the requirements for powering the implanted sensor biodevices. [ABSTRACT FROM AUTHOR]

The performance of range-separated hybrid DFT functional for the calculation of magnetic exchange coupling constant of first-row transition metal complexes has been tested. Scuserian functionals having moderately less HFX (SR) and no HFX (LR) perform better than the other functionals having more HF exact exchange. [Display omitted] • The range-separated functionals having moderately less or no HF exchange are good in predicting J values for 1st row transition metal complexes. • Scuserian HSE functionals having moderately low short-range HF exchange with no LR HF exchange perform better than B3LYP functional. • Among the three Minnesota functionals (M11, N12SX, and MN12SX), M11 provides highest error values for the calculation of magnetic exchange coupling constant. The performance and efficiency of twelve range-separated hybrid functionals are compared with each other in calculating magnetic exchange coupling constant (J) data on eleven di-nuclear first-row transition metal complexes having di-copper (Cu) and di-vanadium (V) as their central atoms. The J values are then compared with the experimental findings. In addition to that we also computed the B3LYP results of these complexes. We compared them with the results obtained from range-separated functionals as well as with the experimental results to understand their performances in predicting the magnetic exchange coupling constant. When computing, we reoptimized all the structures of the complexes taken from the crystal data, and then the values of J s were determined. The performances are predicted in terms of four statistical error matrices, namely, the mean absolute error (MAE), mean fractional error (MFE), mean signed error (MSE), root mean square error (RMSE) in cm−1. [ABSTRACT FROM AUTHOR]

Hot environments cast direct influence on people's well-beings and health besides working productivity during the accelerating global warming. The systematic mechanism is not entirely clear due to the complex human physiological response which also handled human heat strain protection. This study carries out mathematical derivation on the rectal temperature and skin temperature under human heat strain based on the PHS model of ISO 7933 standard. The experimental validation was conducted in a climate chamber with continuously monitoring the typical physiological parameters of 10 subjects in 9 hot working environments. Physiological parameters of subjects were analyzed on average difference (AV), coefficient of variation (CV) and skewness (SKEW) to explore their mutual linkages. Both experimental and theoretical result shows that certain relationship existed between the rectal temperature and skin temperature. The Poisson's ratio on their average value, coefficient of variation, average difference and skew were 0.957, 0.991, 0.990 and 0.941 respectively. Linear relation with coefficient of 0.73 was found between rectal temperature and skin temperature coupling with the constant of 12.09. Comparison on the dynamic changes of rectal temperature and skin temperature was carried out and verified under PHS model. The results showed that rectal temperature was adjusted earlier and more forcefully than skin temperature indicating that human core temperature was better protected under heat stress. The findings contribute to a convenient method of human heat strain prediction when taking rectal temperature as the best physiological threshold with fast human skin temperature and environment parameters monitoring in complex high temperature working environments. • A mathematical model on the prediction of human rectal temperature and skin temperature. • A convenient method on human heat strain prediction with dynamic monitoring on human and environmental parameters. • Accuracy enhancement of the heat stress prediction models with linkage between human physiological indicators. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the cosmological implications and constraints of Weyl-type f (Q , T) gravity. This theory introduces a coupling between the non-metricity Q and the trace T of the energy–momentum tensor, using the principles of proper Weyl geometry. In this geometry, the scalar non-metricity Q , which characterizes the deviations from Riemannian geometry, is expressed in its standard Weyl form ∇ μ g α β = − w μ g α β and is determined by a vector field w μ. To study the implications of this theory, we propose a deceleration parameter with a single unknown parameter χ , which we constrain by using the latest cosmological data. By solving the field equations derived from Weyl-type f (Q , T) gravity, we aim to understand the behavior of the energy conditions within this framework. In the present work, we consider two well-motivated forms of the function f (Q , T) : (i) the linear model represented by f (Q , T) = α Q + β 6 κ 2 T , and (ii) the coupling model represented by f (Q , T) = γ 6 H 0 2 κ 2 Q T , where α , β , and γ are free parameters. Here, κ 2 = 1 16 π G represents the gravitational coupling constant. In both of the models considered, the strong energy condition is violated, indicating consistency with the present accelerated expansion. However, the null, weak, and dominant energy conditions are satisfied in these models. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Perlin effect 1 J C−Hax < 1 J C−Heq was observed for all compounds. • Perlin effect is stronger in 2-halocyclohexanothiones than in the respective ketones. • The medium and the solvent effect do not affect the Perlin effect. Abstract The Perlin effect is an NMR phenomenon observed in six-membered rings and it is referred to as 1 J C−Hax < 1 J C−Heq. In the present work, the influence of halogens (F, Cl and Br) at position 2 in cyclohexanones and cyclohexanethiones is theoretically evaluated on the one-bond C2 H2 coupling constants, i.e. on the Perlin effect. An important hyperconjugative interaction (π C=Y → σ* C-H , Y = O and S) operating in the studied systems seems to play a significant role for the observed 1 J C−Hax < 1 J C−Heq behavior. In addition, the Lewis contribution (J Lewis) dominates the Fermi Contact term (J FC), which plays the major role for the overall one-bond C H coupling constant. Compared to the gas phase, this behavior was found to be insensitive to implicit solvents (DMSO and water). [ABSTRACT FROM AUTHOR]

Abstract Sand deposits cover extensive areas both in the northern and southern hemispheres and the timing and chronology and processes that govern their dynamics are of major interest. Luminescence-based dating methods, are used to date episodic aeolian events but are restricted to late Quaternary deposits, and only reveal the last cycle of sediment burial and not the time of sand existence in the landscape. Burial ages modelled from cosmogenic nuclides reach further back in time, but are usually inferred as minimal deposition ages. It is apparent that standard dating methods, when applied individually, have limited applicability for determining both the age and the processes that form aeolian deposits. This study presents an approach that integrates luminescence dating and cosmogenic burial dating into a stochastic model developed to reproduce sand formation and migration. The model is based on a process in which quartz grains are vertically displaced through a sand column simulating dune migration across the landscape. A range of vertical displacement rates is compiled from published luminescence ages of dated dune fields of varied settings throughout the world. Using these vertical movement rates, sand is recycled up and down a depth profile coupled with a step-wise calculations of cosmogenic nuclides accumulation and decay, alongside OSL signal accumulation. When the modelled sand grains are buried, their luminescence signal grows while 26Al and 10Be decay or accumulate as a function of their respective radioactive decay and production rate, which is governed by cosmic rays attenuation. When sand is exposed at the surface, the luminescence signal is reset and cosmogenic nuclide production is maximized. Each simulation is terminated when the modelled concentrations of 26Al and 10Be reach measured concentrations in actual sand samples. Luminescence data therefore provide the time since last exposure at the surface (i.e. the last depositional cycle), whereas the cosmogenic nuclides provide a long-term estimate of sand residence in the landscape reflecting also weathering and erosion of the source bedrock. The southern Kalahari dune field at Mamatwan, South Africa, is used as a case study to test the presented approach. Model results show that optically stimulated luminescence ages which range between 1 and 10 Ka, only reflect the last cycle of sand migration, while cosmogenic nuclides minimal burial ages are greater than 1 Ma. Furthermore, the simulation results indicate two peaks at 1.5–2.2 Ma and at 4.2–5.2 Ma, suggesting two main phases of sand introduction to the Kalahari during the Pliocene and Pleistocene. Finally, the modelled ages are concurrent with regional environmental and climatic events. The model presented in this study provides a powerful tool for estimating the emergence of sand in a given landscape, and also for understanding the dynamic evolution of any dune field and the mechanisms behind dune migration. [ABSTRACT FROM AUTHOR]

During transients, hydroturbines may demonstrate some dynamic characteristics that differ from the corresponding static characteristics in steady operating conditions. To study the dynamic characteristics of a pump-turbine, we simulated the runaway transients in a model pumped-storage plant by coupling one-dimensional (ID) water conveyance system and three-dimensional (3D) pump-turbine. The results show that the runaway dynamic trajectories form loops in the S-shaped region in the unit discharge and unit torque charts of the pump-turbine, not following the corresponding static characteristics. Theoretical analysis and flow patterns comparisons illustrate that the looping trajectories are mainly caused by the successive features of transient flow patterns, namely, the transient flows in the pump-turbine are influenced by their previous status. These features induce different petformances between similar dynamic operating points in different moving directions. Furthermore, through comparing the transient parameters calculated by the dynamic and static characteristics separately, we found that both methods are available to capture the unstable behaviors of the pump-turbine, but the dynamic method displays more accurate results when simulating the critical transient parameters. Therefore, in practical engineering applications, we suggest to use the static characteristics method for stability analysis while dynamic characteristics method for transient parameters, which is important for optimizing the layout of water conveyance systems. [ABSTRACT FROM AUTHOR]

Atomic scale properties of quadrupole coupling constants ( C Q ) have been evaluated for singular and paired 5-fluorouracil (FU) models. Structural possibilities and properties for various types of hydrogen bonded (HB) homo pairs of FU have been investigated based on density functional theory (DFT) calculations. The models have been optimized to obtain the minimum energy level structures and only the planar molecular pairs have been considered. Various types of HB interactions have also managed the molecular shapes for the FU pairs. Different types of energies and also electron transferring properties have been investigated by the evaluated optimized properties. The atomic scale results indicated different strengths of HB interactions for FU pairs according to the changes of C Q properties for atoms in the singular and paired systems depending on the strength of interactions. [ABSTRACT FROM AUTHOR]

This review paper presents the summary of our investigations in several topics of frequency-domain chipless RFID transponders. The performance comparison of various types of scatterers used in the literature and recently proposed by the authors is presented. The issue of proper location of adjacent resonant elements in the scatterer array to reduce the mutual coupling and consequently ensure the robust RCS response for reliable reading of coded information is addressed. A major improvement in RCS response of transponders is proposed, using slot-in-plate type transponders. Advantages and drawbacks of the proposed solutions are discussed and several open challenges in the field are emphasized. [ABSTRACT FROM AUTHOR]

The RELAP5-3D system analysis code is a generic and flexible analysis program that is used for the analysis of steady-state and transient scenarios of nuclear reactors. While RELAP5-3D has been successfully applied to a very large range of problems, other analysis tools exist that provide either additional accuracy or capability. This paper describes an extensible integrated code system that utilizes the RELAP5-3D analysis code in conjunction with the R5EXEC executive. A description of the different types of time-step algorithms and data transfer methods is provided. Discussions of the various strengths and weaknesses of the coupled code system are provided. Finally, examples of how the coupled code system has been exercised are included. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structural, electronic properties and relative stability of PH 3 F isomers. • Isotropic hyperfine coupling constants, NBO and QTAIM analysis. • Vibrational frequencies and electric dipole moment calculations. • Isomerization, H-elimination and 1,2-hydrogen shift mechanisms. • Thermochemical calculations: H-abstraction vs H-elimination. The aim of this study is to elucidate the reaction mechanism between phosphine and fluorine. Notwithstanding a hydrogen abstraction process is expected in the PH 3 + F reaction yielding PH 2 and HF as the most feasible pathway, the formation of a covalent bound structure (PH 3 F) among reactants leads to a different picture. Therefore, three PH 3 F isomers were characterized showing C 1 (r1) and C s (r2 and r3) symmetries, where the most stable one is in an energy well of 50 kcal mol−1 lower than the energy of the separated reactants. Thus, with the production of the PH 3 F adducts, a H-elimination route became the most favorable pathway forming PH 2 F + H products residing in an energy well of -30 kcal mol−1, while the transition state structure associated with H-abstraction showed a barrier height placed -5.8 kcal mol−1 relative to the separated reactants. Vibrational frequencies and isotropic hyperfine coupling constants of PH 3 F isomers were also perfomed here. [ABSTRACT FROM AUTHOR]

This paper presents the development of MEMS gas preconcentrator (GP) for the detection of trace level Volatile Organic Compounds (VOCs). Besides the development of the MEMS gas preconcentrator, we have also worked on the coupling of this preconcentration device with a micro gas chromatograph (μ-GC) for achieving an accurate detection system for gas trace monitoring. Preliminary results have highlighted a significant contribution of the MEMS GP on the μ-GC efficiency and a detection limit below 35ppbv for different vapors like toluene, vinyl acetate monomer, chloroform and methylisobutylketone was reported. [ABSTRACT FROM AUTHOR]

This paper proposes a novel state feedback delay-range-dependent control approach for chaos synchronization in coupled nonlinear time-delay systems. The coupling between two systems is esteemed to be nonlinear subject to time-lags. Time-varying nature of both the intrinsic and the coupling delays is incorporated to broad scope of the present study for a better-quality synchronization controller synthesis. Lyapunov–Krasovskii (LK) functional is employed to derive delay-range-dependent conditions that can be solved by means of the conventional linear matrix inequality (LMI)-tools. The resultant control approach for chaos synchronization of the master–slave time-delay systems considers non-zero lower bound of the intrinsic as well as the coupling time-delays. Further, the delay-dependent synchronization condition has been established as a special case of the proposed LK functional treatment. Furthermore, a delay-range-dependent condition, independent of the delay-rate, has been provided to address the situation when upper bound of the delay-derivative is unknown. A robust state feedback control methodology is formulated for synchronization of the time-delay chaotic networks against the L 2 norm bounded perturbations by minimizing the L 2 gain from the disturbance to the synchronization error. Numerical simulation results are provided for the time-delay chaotic networks to show effectiveness of the proposed delay-range-dependent chaos synchronization methodologies. [ABSTRACT FROM AUTHOR]

Highlights: [•] Halomethanols experience the generalized anomeric effect. [•] The generalized anomeric effect was found to be due to hyperconjugation in the gas phase and water solution. [•] There is not intramolecular hydrogen bond in halomethanols. [•] The 1 J C,F coupling constant in fluoromethanol is dependent on the molecular dipole rather than hyperconjugation. [ABSTRACT FROM AUTHOR]

The article presents a study which compares the analytical methods of gravity dams-reservoir-foundation interaction. Performed are earthquake analyses of gravity dams with five different heights in a time domain analysis based on the fluid-structure coupling model and the added mass model. Results suggests that the added mass model for dynamic responses of dam-reservoir system are larger than the fluid-structure coupling model.

Abstract: In this paper, we describe a multiscale strategy that allows to couple stochastic and deterministic models. The transition condition enforced between the two models is weak, in the sense that it is based on volume coupling in space (rather than more classical boundary coupling) and on a volume/sample average in the random dimension. The paper then concentrates on the application of this weak coupling technique for the development of a new iterative method for the homogenization of random media. The technique is based on the coupling of the stochastic microstructure to a tentative homogenized medium, the parameters of which are initially chosen at will. Based on the results of the coupled simulation, for which Dirichlet or Neumann boundary conditions are posed at the boundary of the tentative homogenized medium, the parameters of the homogenized medium are then iteratively updated. An example shows the efficiency of the proposed approach compared to the classical KUBC and SUBC approaches in stochastic homogenization. [Copyright &y& Elsevier]

A horizontal upward-facing Zn anode was electrochemically dissolved in aqueous alkaline electrolyte. A plane-parallel upward-facing Ni(OH)2/NiOOH cathode was combined with the Zn anode in a single cell, divided by a polymer separator. This configuration can be regarded as a single pore model inside the porous space of a Zn-NiOOH battery cell. It also insures that the ionic mass transfer rate by diffusion and migration mechanism is dominant over that by natural convection. The morphological variations of the Zn anode surface were examined during the discharge operation of the Zn-NiOOH model cell. Two-dimensional transient concentration profiles of each ion accompanying the electrochemical dissolution of Zn anode in alkaline electrolyte were numerically calculated. The surface morphological variations of the Zn anode were discussed with the aid of numerical simulation. ZnO precipitation on the Zn anode surface was confirmed to be dependent on the horizontal distance from the separator. The present numerical model provides insight to the analysis of observed morphological variations along the Zn anode surface. [ABSTRACT FROM AUTHOR]

To insure the safety of autonomous approaching and capturing of a non-cooperative tumbling target in the on-orbit operating missions, 6 DOF dynamics model of relative translation and rotation is established to describe the relative motion of .two spacecrafts in close distance, and the perturbation induced coupling and dynamic coupling existing in the model are presented to make clear what the coupling effect is. Due to the effects of time-varying and nonlinear terms in the model, the systemized integrator backstepping controller is derived after multi-step recursion with regard to the nonlinear high-order terms. The stability of the controller is proved to be global asymptotic stable based on the Lyapunov's stability theory. With the consideration of rotating characteristic of the target satellite, a linear synchronization rotating approach strategy along the maximum inertial axes is presented to ensure the safety during the final approach. The validity of approach strategy and the effectiveness of controller is verified by the numerical simulation. [ABSTRACT FROM AUTHOR]

Abstract: This work evaluates the efficiency of economic levels of theory for the prediction of 3 J HH spin–spin coupling constants, to be used when robust electronic structure methods are prohibitive. To that purpose, DFT methods like mPW1PW91, B3LYP and PBEPBE were used to obtain coupling constants for a test set whose coupling constants are well known. Satisfactory results were obtained in most of cases, with the mPW1PW91/6-31G(d,p)//B3LYP/6-31G(d,p) leading the set. In a second step, B3LYP was replaced by the semiempirical methods PM6 and RM1 in the geometry optimizations. Coupling constants calculated with these latter structures were at least as good as the ones obtained by pure DFT methods. This is a promising result, because some of the main objectives of computational chemistry – low computational cost and time, allied to high performance and precision – were attained together. [Copyright &y& Elsevier]

Abstract: A theoretical study of FCCF:(HF) n complexes, with n =1 and 2, has been carried out by means of ab initio computational methods. Two types of complexes are formed: those with FH⋯π interactions and those with FH⋯FC hydrogen bonds. The indirect spin–spin coupling constants have been calculated at the CCSD/aug-cc-pVTZ-J computational level. Special attention has been paid to the dependence of the different intramolecular coupling constants in FCCF on the distance between the coupled nuclei and the presence or absence of the hydrogen fluoride molecule. The sensitivity shown by these coupling constants to the presence of hydrogen fluoride is quite notorious. [Copyright &y& Elsevier]

Abstract: Two types of muoniated spin probes were produced by the addition of muonium (Mu) to the phenyl ring of the rod-like liquid crystal 4-(trans-4-pentylcyclohexyl)benzonitrile (PCH5). Avoided level crossing muon spin resonance spec-troscopy was used to characterize the muoniated spin probes and to probe dynamics of PCH5 at the molecular level. The methylene proton hyperfine coupling constant (hfcc) of one of the muoniated spin probes shift in the nematic phase due to the dipolar hyperfine coupling, the ordering of the molecules along the applied magnetic field and fiuctuations about the local director. The amplitude of these fluctuations in PCH5 is determined from the temperature dependence of the methylene proton hfcc. [Copyright &y& Elsevier]

Abstract: We study the performance of density functional methods in the calculation of nuclear quadrupole coupling constants (NQCCs), focusing on the effects of weak intermolecular forces. We begin with an analysis of isolated molecule values, comparing the density functional theory (DFT) results for uracil and thymine obtained by applying 11 different functionals with the Møller–Plesset second-order perturbation theory (MP2) values and with accurate experimental data. Next, using a subset of these DFT functionals we examine the interaction-induced changes of NQCCs for weak solute–solvent interactions, with the solvent effect described as a function of the dielectric constant; for adenine–thymine and guanine–cytosine complexes, in which we observe significant effects due to proton transfer in the hydrogen bonds, and for a hexamine complex in the solid state. Three applied DFT functionals provide a similar, satisfying description of the influence of intermolecular forces on the quadrupole coupling constants, in particular when hydrogen bonding leads to large changes of these constants. [Copyright &y& Elsevier]

Abstract: The voltage-gated ion channels embedded in biological membranes play crucial roles on the generation and transmission of action potentials. Therefore, understanding of impacts of each ion channel is of great importance for the dynamics of neuronal networks. Among the others, one method on this way is to block a specific ion channel type while keeping the remaining ion channel types active across the membrane and to observe their impact on neuronal dynamics. In this study, we study the effects of sodium and potassium channels blockage on the collective spiking regularity of a scale-free neuronal network with stochastic Hodgkin-Huxley neurons, and investigate how the dependence of the collective spiking regularity on the membrane area or cell size varies with the coupling constant between neurons. Results reveal that the collective spiking regularity exhibits coherence resonance (CR) depending on the channel blockage scaling factor and the cell size, where potassium channel blockage enhances the collective spiking regularity whereas sodium channel blockage decreases it. We show that there is a lower limit for the coupling constant which warrants the CR behavior. We also show that the maximal regularity is obtained for a smaller cell size with the increasing the value of the coupling constant. [Copyright &y& Elsevier]

Abstract: It is shown that modeling a part of a molecular system by means of fractional charges is very useful in many situations when its interaction with the rest of the systems is relatively weak as, for instance, in some coordination systems, mixed-valence compounds, molecular adsorption on surfaces, early stages of interactions in chemical reactions, etc. The structural changes in such subsystems can be described by means of orbital charge transfers (OCT) that change the intramolecular vibronic coupling leading to instabilities and distortions of the Jahn–Teller effect (JTE), pseudo JTE (PJTE), and Renner–Teller effect (RTE). A molecular orbital theory of these effects in systems with fractional charges involving orbital vibronic coupling constants and orbital force constants is worked out in the approximation of small OCT. The efficiency of the theory is demonstrated by means of ab initio calculations revealing the vibronic coupling constants and distortions of coordinated molecules in coordination systems and showing how the JTE, PJTE, and RTE allow one to predict and rationalize experimental data. The PJTE instability in coordinated systems with fractional charges is analyzed by considering three coordination compounds, [M(N2H2)(dmpe)2] with M=Fe, Ru (dmpe=Me2PCH2CH2PMe2), and [(N2H2)Ru2DPB(Im)2] (DPB=diporphyrinato-biphenylene tetraanion, Im=imidazole), in which the η2-coordinated N2H2 molecule distorts from a trans-planar to a nonplanar (C2) shape due to OCT to and from its frontier orbitals. As an example of the induced JTE in coordinated molecules the [(triphos)RhH(η1: η2-P4)] complex is considered, and it is shown that the white phosphorus (P4) distortion from tetrahedron to butterfly geometry by coordination is due to the OCT to its excited degenerate t 1 orbital. The RTE effect in coordinated systems is demonstrated by the distortion of the acetylene molecule from its linear configuration to the non-linear cis-form by its coordination in Y-η2-C2H2 and Pd-η2-C2H2 systems. [ABSTRACT FROM AUTHOR]

A method for enhancing nuclear fuel cycle proliferation resistance (PR) assessment through the direct coupling of nuclear materials depletion and decay analysis is presented in this paper. This direct coupling of nuclear materials analysis with PR evaluation affords new avenues of PR evaluation, including the evaluation of the cycle-level sensitivity to factors such as reactor type, fuel enrichment, and fuel burnup, all of which result in changes to materials properties that cascade throughout the system. This analysis can be useful to identifying the conditions under which nuclear energy systems show a heightened PR sensitivity and warranted further characterization. This paper extends prior work in the coupling technique; in addition to making use of a more sophisticated material attractiveness evaluation and a stage weighting sensitive to the material mass flow of the system, further categories of systems are evaluated. A demonstration analysis is applied to three classes of fuel cycles across varying parameters: open cycles consisting of no actinide recycle, modified open cycles with limited actinide recycling, and fully closed cycles in which all actinides are recycled as fuel. While the Fuzzy Logic Barrier Model developed at North Carolina State University shall be used as a demonstration platform for this effort, this technique can be applied to enhance many models for fuel cycle PR assessment. [ABSTRACT FROM AUTHOR]

Systems of coupled prognostic mesoscale and microscale models have been suggested as a tool to accurately simulate flows around artificial structures and over densely built urban areas. Implementations of such two-way coupling are burdened by scale mismatches as well as the formidable computational cost of online microscale calculations. A simplifying approach is proposed, where microscale feedbacks are spatially and temporally upscaled and assimilated into the mesoscale calculation. A two-way coupled model system is developed, consisting of the mesoscale model MEMO and the microscale model MIMO, employing interpolating metamodels. As an illustrative application, multi-day simulations for Athens, Greece are presented. [ABSTRACT FROM AUTHOR]

Abstract: The methodology of natural bond orbital (NBO) analysis has been applied to the study of alkyl and cycloalkyl radicals with the objective of finding relationships between donor/acceptor computed stabilization energies and isotropic Fermi contact couplings (HFCs). A linear correlation was found between computed β-C–H hyperfine coupling constants and 2nd order perturbation energies, i.e. hyperconjugation. A linear correlation was established between HFCs and the complete range of cos2 θ of dihedral angles defined by the orbital axes of 2pC-radicals with vicinal β-C–H* bonds. The dominant spin transmission mechanism is attributed to hyperconjugation with smaller contributions from spin polarization. [ABSTRACT FROM AUTHOR]

Abstract: We show that a triple-product correlation in the neutron radiative _-decay rate, characterized by the kinematical variable η ≡ (le×lv) k, where n(p) → p(p’)+e-(le)+ve(lv)+γ(k), isolates the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and SU(2)L_U(1)Y gauge invariance at low energies. The correlation appears if the imaginary part of the coupling constant is no zero, so that its observation at anticipated levels of sensitivity would reflect the presence of sources of CP violation beyond the Standard Model. We compute the size of the asymmetry in n → pe-veγ decay as a function of the coupling, estimate the e_ect ofStandard-Model final-state interactions, and discuss the role nuclear processes can play in discovering the e_ect. [Copyright &y& Elsevier]

Abstract: The Fibre Active Scintillator Target (FAST) experiment at the Paul Scherrer Institute was designed to measure the μ+ lifetime to 4 ps precision and thereby to determine the Fermi coupling constant, GF, to 1 part per million (ppm). In FAST, a π+ beam was stopped inside a highly granular target which images the entire π+→μ+→e+ decay chain. To achieve the high statistics required, the detector has a modular structure which allows simultaneous measurements of several decay chains. The concept of the FAST detector provides strong intrinsic suppression of potential systematic effects and allows operation at high beam rates. In 2008 and 2009, FAST collected a total statistics of 4.2×1011 identified μ+ decays, allowing a statistical sensitivity of 1.5ppm on GF. The current status on the analysis of these data is presented. [Copyright &y& Elsevier]

This paper is concerned with further development of a recently proposed algorithm for control allocation to recover from pilot-induced oscillations (CAPIO). When actuators are ate-saturated due to either an aggressive pilot command, high gain of the flight control system, or some anomaly in the system, the effective time delay in the control loop may increase. This effective time-delay increase manifests itself as a phase shift between the commanded and actual signals and can instigate pilot-induced oscillations. CAPIO reduces the effective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. Theoretical stability analysis results are presented for a scalar input-signal case. Simulation results for an unstable aircraft with cross-coupling and multiple control channels demonstrate the potential of CAPIO serving as an effective pilot-induced oscillation handler in adverse conditions. [ABSTRACT FROM AUTHOR]

Abstract: A novel inclusion complex of the propiconazole nitrate (NO3PCZ) with β-cyclodextrin (β-CD) was prepared by treatment of propiconazole (PCZ) with an acidic nitrating agent. The formation of NO3PCZ and its inclusion complex with β-CD has been studied by NMR, ESI–MS, TGA, DSC methods. Using the undecoupled signal in the HMBC correlation spectra, almost identical coupling constants of CH from trizolic ring of PCZ and NO3PCZ compounds (1J(HC)3=207Hz, 1J(CH)5=214Hz, for PCZ; 1J(HC)3=208Hz and 1J(CH)5=215Hz, for NO3PCZ) were determined, confirming that the geometry of the heterocyclic skeleton is identical in both the forms. The 1:1 stoichiometry of the complex was determined by ESI–MS and was confirmed using Scott''s equation in DMSO and Higuchi and Connors equation in water. The solubility curve obtained for NO3PCZ in presence of β-CD in distilled water was constructed, resulting in a solubility diagram of AL type. Solubility of NO3PCZ in water was determined by DLS studies. The results showed that NO3PCZ was encapsulated within the β-CD cavity with a binding constant of 330 M-1 in DMSO and 975 M-1 in water. Preliminary pharmacological studies showed higher antifungal activities for NO3PCZ and its inclusion complex, compared with its PCZ analog. The acute toxicity of the complex is smaller than the pure or modified drug, recommending the inclusion complex as future promising therapeutic agents. [Copyright &y& Elsevier]

Abstract: We present a scheme for the coherent population transfer of a three-level system in a quantum dot molecule by means of the interdot tunnel-coupling which can be controlled by a bias voltage. Under proper combination of the pump laser pulse and the tunnel-coupling pulse, an almost complete population transfer from the state without excitations to the indirect exciton state can be achieved. Additionally, by tuning the tunnel-coupling pulse, an arbitrary coherent superposition of the two states can also be prepared. [Copyright &y& Elsevier]

Two novel polyazines were successfully synthesized via palladium-catalyzed Suzuki coupling method of N,N′-bis(5-bromothiophene)-2-aldehyd azine with 2,5-thiophenediboronic acid and 9,9-dioctylfluorene-2,7-diboronic acid, respectively. The polymers were characterized by 1H-NMR, FT-IR and UV-VIS spectroscopy. The thermal properties of the polymers were investigated by TGA analysis. The semi-crystalline structure of these compounds was demonstrated by X-ray diffraction study. [ABSTRACT FROM AUTHOR]

Abstract: We present Monte Carlo simulation data about Holmium magnetic thin film structures. As well known, this rare earth shows, at transition temperature , a helical order in the bulk phase. In contrast with the collinear ferromagnetic or antiferromagnetic thin films, recent experimental works have proven that the transition temperature ( being the film thickness) depends on only by an empirical relation. In order to study the behavior of these film structures, we consider a Heisenberg model with easy-plane single ion anisotropy and seven coupling constant ( in the plane and between plane of the Ho structure), obtained by experimental neutron measurements. [Copyright &y& Elsevier]

The core of this research is to study tribotechnical characteristics of powder composite materials under the conditions of chain couplings functioning. We recommend utilizing powder composite materials with a rough heterogeneous structure to produce complex shaped half-couplings toothings. [ABSTRACT FROM AUTHOR]

This paper presents a coupling solution for determining the elastic interfacial shear and normal stresses of a plated beam. The mismatch of the curvatures in the beam and plate is considered. This leads to the coupling of governing differential equations for the interfacial shear stresses and normal stresses. Existing solutions assume the beam and plate have an equal curvature to uncouple this effect. In this paper, however, it is shown that the mismatch of curvatures leads to a larger interfacial shear stress but a lower normal stress. The unequal curvatures resulting from the elastic deformation of the adhesive layer will have an obvious contribution to the bending moment distribution on beam and plate, especially when the flexural rigidity of the bonded plate increases: the vertical deformation of the adhesive layer near the end of plate will become larger and then results in an increasing contribution by interfacial stresses. These findings are therefore very important to the design of strengthened beams. [ABSTRACT FROM AUTHOR]

Water flow in the subsoil generates electrical currents measurable at the ground surface with the self-potential (SP) method. These measured potentials, which result from hydroelectric coupling, are called streaming potentials and are well correlated with the geometry of the water table. The particle swarm algorithm can be used to estimate the water-table elevation from SP data measured at the ground surface. The basic idea behind particle swarm optimization (PSO) is that each model searches the model space according to its misfit history and the misfit of the other models (particles) of the swarm. PSO is a simple, robust, and versatile algorithm with a very good convergence rate (typically before 3000 forward runs), and it can explore a large model space without being time consuming. Based on samples gathered in a low-misfit area, we have computed a fast approximation of the posterior distribution of the water table, the electrokinetic coupling constant, and the reference hydraulic head. Although PSO is a stochastic search technique, our convergence results, based on the stability of particle trajectories, specify clear criteria to tune PSO parameters. [ABSTRACT FROM AUTHOR]

The explosive growth in the use of the Internet and multimedia applications in both the home and the office has fueled the requirement for high-bandwidth communication systems capable of processing huge volumes of data in a prompt and reliable manner Plastic optical fiber (POF) has emerged as an ideal solution for meeting this requirement and is now speafled by many architects as a simple, one-cable solution for home and office data communication networks. This study presents a modified flip-chip light emit- ting diode (LED) package for use in short-distance, POF-based communication systems. In contrast to the planar surface of the traditional design, the proposed LED package has a curved boundary surface between the underfill and the air This boundary surface functions as a virtual lens, which focuses the light emitted by the LED into the acceptance cone of the optical fiber such that the amount of light coupled into the fiber core is maximized. The proposed design yields an average coupling efficiency of around 49.6% over an LED-optical core misalignment range of 0.4-3 mm. Furthermore, the curved boundary surface reduces the distance between the emitting source and the ambient environment; therefore, it improves the thermal dispersion efficiency of the LED package. [ABSTRACT FROM AUTHOR]

Abstract: A micro power generator harvesting vibration energy by resonant inertial oscillation of a piezoelectric laminated cantilever with proof mass was designed, fabricated, and characterized. The active part with 2 µm thick PZT on 5 µm silicon was equipped with interdigitated electrodes to achieve higher voltages. A coupling constant k2 =5% was derived from the difference in resonance frequencies at low and high impedance. At optimal load impedance, a voltage of 1.6 V and an output power of 1.4 µW was measured with a 0.8x1.2 mm cantilever having an active area of 0.8x0.4 mm, excited with 2g at 870 Hz. [Copyright &y& Elsevier]

This paper deals with the design methodology of multi-variable flight control systems through a H∞ loop-shaping technique. A new procedure for the design of non-diagonal pre-and post-compensators is described. En particular, important improvements over existing methods are introduced to both make the selection of weights easier and to contain the order of the resulting controller. The new procedure can be easily managed through suitable Matlab commands and functions, thus simplifying the whole algorithm implementation and providing an effective control system design with a minimum effort. Two typical design problems are addressed: a pitch pointing control system and a lateral controller for coordinated turns. In both cases, a good decoupling between existing channels is obtained by means of a non-diagonal pre-compensator which shapes the plant transfer function, and provides the desired response settling time. The design approach is particularly effective even for nominal plants with strong cross-coupling between channels. The design procedure is illustrated with the aid of a Matlab/Simulink model of a single seat fighter aircraft. We show that a trade-off between the conflicting requirements of fast response and moderate use of control surfaces can be easily managed by varying the constant terms of the diagonal post-compensator. [ABSTRACT FROM AUTHOR]

Abstract: The development of Karplus‐type formulas that relate the NMR coupling constants of carbohydrates and related ma olecules to the dihedral angle between the coupled nuclei is surveyed, including couplings over three, four, or five bonds. Most of the major types of coupling constants of interest in carbohydrate characterization are described, including several kinds of proton–proton couplings, those between protons and heteronuclei, and others involving two heteronuclei, over a number of different coupling pathways. The equations range from simple, two‐parameter versions that depict only the torsional dependence of coupling constants, to complex 22‐parameter forms that simulate the variation of the coupling with many different molecular properties. Methods for formulation of the Karplus relationships are discussed, including multidimensional NMR methods, molecular modeling, and theoretical computations that have been used either to support the experimental measurements, or as stand‐alone techniques for elucidation of molecular geometry, and the calculation of coupling constants for direct definition of the equations. Online calculator programs for coupling constants and torsion angles are described. [Copyright &y& Elsevier]

Abstract: We design an efficient coupler to transmit light from a strip waveguide into the flatband slow mode of a photonic crystal waveguide with ring-shaped holes. The coupler is a section of a photonic crystal waveguide with a higher group velocity, obtained by different ring dimensions. We demonstrate coupling efficiency in excess of 95% over the 8 nm wavelength range where the photonic crystal waveguide exhibits a quasi-constant group velocity and observe a more than 12-fold intensity enhancement in the slow-light waveguide. An analysis based on the small Fabry–Pérot resonances in the simulated transmission spectra is used for studying the effect of the coupler length and for evaluating the coupling efficiency in different parts of the coupler. The mode conversion efficiency within the coupler is more than 99.7% over the wavelength range of interest. The parasitic reflectance in the coupler, which depends on the propagation constant mismatch between the slow mode and the coupler mode, is lower than 0.6%. [Copyright &y& Elsevier]

This account summarizes recent developments in the use of cheap, benign, and non-toxic iron salts as precatalysts for various cross coupling reactions. Although not yet nearly as mature as their palladium- or nickel-catalyzed counterparts, these transformations provide efficient and scalable solutions for many types of C--C-bond formations. Selected applications to the total synthesis of bioactive natural products illustrate the present state of the art. [ABSTRACT FROM AUTHOR]

Catalytic cross-dehydrocoupling polymerization of phenylsilane (1) with water was investigated. Among transition metal derivatives investigated, Pd[sub2](dba)[sub3] is the most active catalyst for the polymerization, which affords a high molecular weight polymer (P1) soluble in common organic solvents (M[subw]/M[subn] = 62200/25400). The polymer can be cast into a film. The polymerization was monitored by SEC and [sup29]Si NMR. It was shown that hydrolysis of Sill and cross-dehydrocoupling reaction between Sill and SiOH are faster compared to dehydration of SiOH in this polymerization, and plausible reaction mechanism was suggested. Chemical structure and thermal property of P1 was characterized by NMR, IR, and TGA. [ABSTRACT FROM AUTHOR]

The magneto-structural correlation shows that the magnetic coupling constant of the complex decreases with an increase in the Cu O Cu bond angle (θ). When θ > 90.95°, the magnetic interactions are altered from ferromagnetic to antiferromagnetic interactions. [Display omitted] • Magnetic properties of a phenoxido-bridged dicopper(II) complex were studied. • The magneto-structural correlation was dependent on the Cu O Cu bond angle. • Paramagnetic centers were dominated by spin delocalization. In this work, the magnetic properties of the phenoxido-bridged binuclear copper complex [Cu 2 (LMe,Me,Me) 2 ] were studied using the density functional theory-broken symmetry method by employing various functionals and basis sets, and the magneto-structural correlation was established. Encouraging results were obtained using the wB97X/def2-TZVPP level of theory, as the calculated magnetic coupling constant (−198.03 cm−1) was close to the experimental value (−197.55 cm−1). Molecular magnetic orbital and spin density analyses proved that the molecular magnetic orbital is composed of Cu(1)/Cu(2) 3 d z 2 orbitals and phenoxido-bridged ligand-conjugated π-type molecular orbitals, and the paramagnetic centers are dominated by spin delocalization. The magneto-structural correlation proved that the magnetic coupling constant of the complex initially increases and subsequently decreases with increase inthe Cu O Cu bond angle (θ). As the bond angle (θ) increases, the character of the exchange is altered from ferromagnetic to antiferromagnetic. [ABSTRACT FROM AUTHOR]

[Display omitted] • Delivery of tioguanine by a model of fullerene was investigated. • Two bimolecular configurations were found for possible adsorption of tioguanine by fullerene. • Five-member ring of tioguanine was more favorable position for placing toward the fullerene. • Tendency of tioguanine@fullerene could be increased in comparison with single tioguanine. • The results were suggesting a model for further investigations of drug delivery purposes. The advantage of employing a model of iron (Fe)-doped carbon-20 fullerene cage (C) for delivery of tioguanine (TG) anticancer drug was investigated in this work by performing density functional theory (DFT) calculations. The models were optimized and corresponding electronic and structural features were evaluated to analyze the model systems of this work. Based on examining relaxation of TG at the C surface, two configurations of TG@C1 and TG@C2 were obtained regarding the orientation of sulfur-mediated TG from six-member ring or five-member ring towards the Fe-doped region of C surface. The calculations indicated that both models could be stabilized with more favorable features in energy and molecular orbitals for TG@C2 model than TG@C1 model. Further analyses of molecular orbital features also indicated mechanism of bimolecular formations. Additionally, the calculated atomic quadrupole coupling constants (QCC) approved achievements of molecular features to recognize TG@C2 as more favorable model for proposing for further investigations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two single models of 6TG were investigated for Fe-chelation. • Three bimolecular models of 6TG were investigated for dual chelation of Fe. • S atom of 6TG was the dominant atomic position for Fe-chelation. • Complementary N atom of pyrimidine or imidazole rings assisted S for Fe-chelation. • N atom of imidazole ring helped S atom for F-chelation more than N atom of pyrimidine ring. • Dual chelation of Fe was successfully done for the investigated 6TG systems. 6-Thioguanine (6TG) was investigated in this work for chelating iron (Fe) by assistance of sulfur (S) atom through density functional theory (DFT) calculations. 6TG was first participated in Fe-chelation process to form S1 and S2 models by help of nitrogen (N) atom of pyrimidine and imidazole rings. The results indicated that S2 model could be stabilized better than S1 model with more appropriate value of binding energy (BE). Fe-mediated formation of bimolecular models were based on combining each of S1 and S2 models to yield S11, S12 and S22 models; S22 could work for the best model of dual chelation of Fe. Quadrupole coupling constants (Qcc) also approved significant changes of electronic properties at the atomic sites to show impact of Fe-chelation process on the properties of molecules. Hence, dual chelation of Fe by 6TG was proposed with this work to arise more insights about unknown anticancer functions of 6TG. [ABSTRACT FROM AUTHOR]