Mixed Configuration Research Articles

Entanglement negativity at large central charge

We establish the large central charge behaviour of the entanglement negativity for a mixed state configuration of a single interval enclosed between two intervals in a holographic $CFT_{1+1}$. To this end we utilize the monodromy technique to elucidate the large central charge limit of a four point twist correlator which characterizes the negativity of the mixed state configuration. Subsequently we analyze the large central charge limit of the six point twist correlator which reduces to the above four point correlator in a specific limit. The results provide a strong consistency check for our recently proposed holographic entanglement negativity conjecture in the $AdS_3/CFT_2$ scenario.

The effects of mass, bulk and stiffness of personal protective equipment and clothing on physical performance when performing a military mobility obstacle course

BackgroundSoldiers are required to conduct tasks and operations in physically demanding situations, where the ability to move (mobility) quickly is important to lethality and survivability.This study employed a specially designed suit to try to isolate the main mass property characteristics of personal protective clothing/equipment (PPCE) including mass, bulk and stiffness as much as possible and evaluated their effects on soldier performance across operationally-relevant mobility tasks. MethodEight male military subjects performed the load effects assessment program (LEAP) obstacle course while wearing 7 different configurations of specifically designed suit: unencumbered (control), 10 kg mass, 30 kg mass, 20 L bulk, medium stiffness, high stiffness and a mixed configuration consisting of 10 kg mass, 20 L bulk and medium stiffness. The primary outcome measure was total LEAP completion time. Additionally, heart rate, rating of perceived exertion (RPE), range of motion and vertical jump heights were measured and related to LEAP performance. ResultsAll configurations degraded or tended to degrade the total LEAP completion times (p-value < 0.05), except for the medium stiffness configuration. Heart rate did not differ significantly between configurations, while RPE scores of configurations 30 kg and mix were significantly higher compared to control (p < 0.01). ConclusionMass, bulk and stiffness all negatively influence LEAP obstacle performance. Therefore, all three have to be considered when trying to reduce the physical burden on soldiers.

Hexagonal and mixed arrays of flow channel design in counterflow heat exchanger

Heat exchanging is one of the critical process in a thermal system and requires in depth optimization of equipment configuration. In this study, the advantage of morphing the flow channel design to more complicated configuration is shown for the purpose of enhancing the flow and thermal characteristics of counterflow heat exchanger. The free pursuit for the optimal geometry of flow channel cross-sections will be investigated toward meeting two objectives simultaneously: lower longitudinal (along the flow direction) flow resistances and lower perpendicular (channel to channel) thermal resistance. For hexagonal, square, and triangular ducts, an analytical model is used to evaluate the fluid flow and heat transfer relative performances. The hexagonal array can be packed tightly without leaving spaces in between, such as in packing circular tubes. However, having inactive channels within the hexagonal bundle is one of the main challenges that reduce the thermal performance of counterflow heat exchanger. Thus, a hybrid packing of mixed configurations is considered in this paper for which a 3D numerical model (CFD) is used to analyze its thermal and fluid flow features. The findings reveal that the triangular array offers higher thermal performance as compared to that of the competitive arrays. However, when heating and flow effects are considered simultaneously, the hybrid array provides the improved performance among the other configurations considered.

Energy structure investigations in triply ionized mercury: Hg IV

We report energy level structure of triply ionized mercury (Hg IV). The spectrum was recorded on a 3-m normal incidence vacuum spectrograph in the wavelength region 300 – 2000 Å, using a triggered spark source at the spectroscopy laboratory, St. Francis Xavier University, Antigonish in Canada. Wavelength measurement and the corresponding uncertainties caused by calibration procedures are carefully analyzed. Based on the analysis of original measurements, the energy levels are optimized, which resulted in an improved set of energy level values. A complete disentanglement of the origin of these energy levels may well be impossible; therefore, new configurations have been extended in our theoretical calculations using Cowan's pseudo-relativistic Hartree-Fock code with superposition of interacting configurations. All preceding results were confirmed, and the 5d8(6d + 7s) mixed configurations have been newly established with the aid of experimental data supported by theoretical calculations. Along with the optimized energy eigenvalues, the observed and Ritz wavelengths, transition rates, and eigenvector compositions of Hg IV are also given. The energy level values were optimized using a computer code LOPT.

The Effects of Interface Views on Performing Aerial Telemanipulation Tasks Using Small UAVs

This paper presents a human-robot interaction (HRI) study of a dedicated Mission Specialist interface for performing telemanipulation tasks using a small unoccupied aerial vehicle (UAV). Current literature suggests that the successful completion of aerial manipulation tasks in real-world environments requires human input due to challenges in autonomous perception and control. Visual information of the remote environment in a telemanipulation interface can significantly affect performance under direct control; however, the effects of interface visualizations on task performance have not been studied for UAV telemanipulation. This work evaluated the effects of interface viewpoint on aerial manipulation task performance. The interfaces evaluated in this study included video streams from cameras located onboard the UAV, including: (i) a manipulator egocentric view, (ii) a manipulator exocentric view, and (iii) a combination of egocentric and exocentric views. A total of 36 participants completed three different manipulation tasks using all three interface conditions. The observations and results showed that both the exocentric and mixed view configurations contributed to improved task performance over an egocentric-only interface. Further, this study resulted in data regarding view use, view effectiveness, and task type that can be used for further developing interfacing for aerial manipulators that change and adapt to the environment and task.

Mixed-cation driven magnetic interaction of interstitial electrons for ferrimagnetic two-dimensional electride

Magnetism of pure electrons is fundamental for understanding diverse magnetic phenomena in condensed matters but has not been fully investigated in experiments due to the lack of a tractable model system. Such an exotic material necessitates an exclusive magnetic interaction of electrons being devoid of orbital and lattice degrees of freedom. Here, we report the two-dimensional mixed-cation [YGdC]2+∙2e− electride, showing ferrimagnetic nature from the direct exchange interaction of magnetic interstitial electrons in interlayer space. We identify that magnetic interstitial electrons are periodically localized in octahedral and tetrahedral cavities between 2D cationic Y2−xGdx arrays. The mixed configuration of non-magnetic and magnetic cations in cavities induces divergent spin states and interactions of magnetic interstitial electrons, in which their direct exchange interaction overwhelms the interactions with magnetic cations, triggering the ferrimagnetic spin-alignment. This discovery facilitates further exploration of magnetic electrides and nurtures the study of two-dimensional magnetism of layered crystals and electron phases.

A bi-objective simulation-based optimization algorithm for redundancy allocation problem in series-parallel systems

The present study proposes a bi-objective simulation-based optimization model applicable to the redundancy allocation problem (RAP) with heterogeneous components for the objective functions of system reliability maximization and system cost minimization. Proposed RAP identifies the optimal component types, the redundancy level, and the redundancy strategy, comprising active, cold-standby, mixed, or K-mixed configurations, with imperfect switching. Based on the stochastic nature and NP-hard complexity of the problem, except for the active redundancy strategy, there is no analytical closed-form method for accurately assessing system reliability. Hence, earlier studies carried out system reliability optimization by single-stage stochastic techniques that estimate the lower Lagrangian function bound. This limitation adds to the design cost and hinders greater system reliability. Generally, one cannot analytically evaluate system reliability. The present study employs simulation sampling in order to make efficient and unbiased reliability estimates. 4Dscript interpreting programming is utilized to design the computerized simulation model. Since RAP has a combinatorial nature, the present study exploits the controlled elitist non-dominated sorting genetic algorithm (NSGA-II) to obtain Pareto-optimal fronts with properly-distributed optimal points. Various benchmark solutions of the literature are investigated to validate the developed model and evaluate the proposed NSGA-II method efficiency. The findings revealed satisfactory performance in system reliability enhancement and total system cost reduction compared to the earlier methods.

Nuclear structure and band mixing in Pt194

We introduce a two-particle, two-hole mixed configuration scheme to fit $E2$ strengths for the $0\ensuremath{\leftrightarrow}2, 2\ensuremath{\leftrightarrow}4$, and $4\ensuremath{\leftrightarrow}6$ transitions in $^{194}\mathrm{Pt}$. The interaction includes two sets of pairing operators, {${S}^{\ifmmode\pm\else\textpm\fi{}}(t),{S}^{0}(t)$} $(t=s,d)$. Solutions within this framework are used to analyze energy spectra, $E2$ transitions, and band-mixing features of the model. The results confirm that mixing is small and similar for $J=2$, 4, and 6, with the calculated energies and transition matrix elements in excellent agreement with experimental data.

Influence of plastic deformation on the microstructural and magnetic properties of some Fe-based alloys

We report the morphological and magnetic properties of deformation-induced martensite characteristics in the austenite phase of Fe69Ni27Mn4 and Fe67Ni27Mn4Zn2 (wt %) alloys after 30% plastic deformation. Scanning electron microscopy (SEM) and also physical property measurement system (PPMS) facilities were applied to investigation to clarify the deformation-induced martensite characteristics from morphological and magnetic points of view. Scanning electron microscope observations showed elongated deformation-induced martensite morphology in the austenite phase of the examined alloys. Additionally, two alloys exhibited typical ferromagnetism in their martensite phase. The saturation magnetization (Msat) was found to be firstly increased and then decreased with increasing temperature. We found that the % Zn addition shifts the Curie temperature (Tc) of Fe–Ni–Mn alloys to higher temperatures. The largest Msat (~ 27 emu·g−1), the Hc (~ 26 Oe), and Tc (~ 248) were obtained for the Fe–Ni–Mn–Zn alloy with a mixed configuration of bcc and fcc phases.

Nuclear moments of germanium isotopes near N=40

Collinear laser spectroscopy measurements were performed on $^{69,71,73}$Ge isotopes ($Z = 32$) at ISOLDE-CERN. The hyperfine structure of the $4s^2 4p^2 \, ^3P_1 \rightarrow 4s^2 4p 5s \, ^3P_1^o$ transition of the germanium atom was probed with laser light of 269 nm, produced by combining the frequency-mixing and frequency-doubling techniques. The hyperfine fields for both atomic levels were calculated using state-of-the-art atomic relativistic Fock-space coupled-cluster calculations. A new $^{73}$Ge quadrupole moment was determined from these calculations and previously measured precision hyperfine parameters, yielding $Q_{\rm s}$ = $-$0.198(4) b, in excellent agreement with the literature value from molecular calculations. The moments of $^{69}$Ge have been revised: $\mu$ = +0.920(5) $\mu_{N}$ and $Q_{\rm s}$= +0.114(8) b, and those of $^{71}$Ge have been confirmed. The experimental moments around $N = 40$ are interpreted with large-scale shell-model calculations using the JUN45 interaction, revealing rather mixed wave function configurations, although their $g$-factors are lying close to the effective single-particle values. Through a comparison with neighboring isotones, the structural change from the single-particle nature of nickel to deformation in germanium is further investigated around $N = 40$.

Hybrid LCC-AAC HVDC transmission system

A hybrid HVDC transmission system based on a line-commutated converter (LCC) and an alternate arm converter (AAC) is developed in this article. The basic operation principles and control methods of the proposed LCC-AAC hybrid HVDC system are demonstrated following with appropriate system design and parameter selection. In addition, this paper proposes a set of control schemes for riding through ac faults and handling dc fault. The operation and performance of both converters in such a hybrid HVDC configuration are verified through a detailed set of results based on a 3000 MVA LCC-AAC hybrid HVDC system including steady state operation, ac-grid harmonics & dc-side ripple analysis, reference tracking (active power change at LCC station, reactive power change at AAC station) and system performance under ac-grid faults without blocking converter at both terminals of the HVDC system. Also, the response of the hybrid system under dc fault presents potential dc fault handling capability compared with the hybrid system based on LCC and modular multilevel converter (MMC) with half-bridge submodules (HBSMs). The hybrid LCC-AAC HVDC transmission system lays preliminary steps for research on complex mixed converter multiterminal dc configurations in future dc super grids.

Study of excitation energies and transmission potential of the reduced quadruple B (E2) for the 70Zn isotope by applying the nuclear shell model

In this paper, the excited energy levels and reduced electric quadrupole transition probabilities (BE2 ↓) in both pure and mixed configuration s of 70Zn nucleus have been calculated by applying the nuclear shell model. In the present study, the surface delta and modified surface delta interactions within the model space (1p3/2,0f5/2, 1p1/2 and 0g9/2) have been used for two protons outside the closed nuclear core represented by the 68Ni nucleus. The equations are programmed for the above two interactions and the reduced electric quadrupole transition probabilities (BE2 ↓) equations using the Fortran version 95. Through the used Fortran version 95 program code, the elements of the matrix have been calculated for two particles which are necessary to calculate the eigenvalues, the eigenvectors and then the final energies of the nucleus that has been used in the current study. Through the calculations, theoretical results that have well agreement with the available practical values have been obtained. The total angular momentum and parity of some uncertain and unspecified energy levels have been confirmed and determined by the total angular momentum and the practical parity. Also, new values have been identified for both the excited energy levels and the reduced electric quadrupole transition probabilities (BE2 ↓), these values are considered as a suggestion that increases theoretical knowledge of each of the energy levels and the expected transition probabilities during this study.

A 3-D Simulation of a Single-Sided Linear Induction Motor with Transverse and Longitudinal Magnetic Flux

This paper presents a novel and improved configuration of a single-sided linear induction motor. The geometry of the motor has been modified to be able to operate with a mixed magnetic flux configuration and with a new configuration of paths for the eddy currents induced inside the aluminum plate. To this end, two slots of dielectric have been introduced into the aluminum layer of the moving part with a dimension of 1 mm, an iron yoke into the primary part, and lastly, the width of the transversal slots has been optimized. Specifically, in the enhanced motor, there are two magnetic fluxes inside the motor that circulate across two different planes: a longitudinal magnetic flux which goes along the direction of the movement and a transversal magnetic flux which is closed through a perpendicular plane with respect to that direction. With this new configuration, the motor achieves a great increment of the thrust force without increasing the electrical supply. In addition, the proposed model creates a new spatial configuration of the eddy currents and an improvement of the main magnetic circuit. These novelties are relevant because they represent a great improvement in the efficiency of the linear induction motor for low velocities at a very low cost. All simulations have been made with the finite elements method—3D, both in standstill conditions and in motion in order to obtain the characteristic curves of the main forces developed by the linear induction motor.

Accurate prediction of core-level spectra of radicals at density functional theory cost via square gradient minimization and recoupling of mixed configurations.

State-specific orbital optimized approaches are more accurate at predicting core-level spectra than traditional linear-response protocols, but their utility had been restricted due to the risk of "variational collapse" down to the ground state. We employ the recently developed square gradient minimization [D. Hait and M. Head-Gordon, J. Chem. Theory Comput. 16, 1699 (2020)] algorithm to reliably avoid variational collapse and study the effectiveness of orbital optimized density functional theory (DFT) at predicting second period element 1s core-level spectra of open-shell systems. Several density functionals (including SCAN, B3LYP, and ωB97X-D3) are found to predict excitation energies from the core to singly occupied levels with high accuracy (≤0.3 eV RMS error) against available experimental data. Higher excited states are, however, more challenging by virtue of being intrinsically multiconfigurational. We thus present a configuration interaction inspired route to self-consistently recouple single determinant mixed configurations obtained from DFT, in order to obtain approximate doublet states. This recoupling scheme is used to predict the C K-edge spectra of the allyl radical, the O K-edge spectra of CO+, and the N K-edge of NO2 with high accuracy relative to experiment, indicating substantial promise in using this approach for the computation of core-level spectra for doublet species [vs more traditional time dependent DFT, equation of motion coupled cluster singles and doubles (EOM-CCSD), or using unrecoupled mixed configurations]. We also present general guidelines for computing core-excited states from orbital optimized DFT.

A review on RF micro-electro-mechanical-systems (MEMS) switch for radio frequency applications

This paper is designed to review the MEMS switch by considering key aspects on the basis of mechanical structure, actuation methods, and types of contact and circuit configurations. The cantilevered and clamped–clamped switch structures are explored and discussed. Actuation methods and switch configurations have also been covered to give more insights about their placements and performances in RF systems. The electrostatic and piezoelectric actuation mechanisms can result in fast RF MEMS switches and better reliability but at the cost of increased pull-in voltage. The electrostatic method is mostly employed in MEMS switches due to its distinctive advantages. The resistive switch uses less actuation voltage compare to a capacitive switch but suffers from reliability issue. Nevertheless, the capacitive MEMS switches are prominent in use over ohmic contact switches due to better RF performance and reliabilities by offering lifetime of 3–10 million cycles. The RF MEMS switches can be placed in series, shunt and mixed configurations as per application requirements. Capacitive switches are mostly utilized in RF systems and placed in shunt with coplanar waveguide signal lines. These RF MEMS switches find applications in sensors, resonators, amplifiers, phase shifters, and MEMS satellite vehicles for space applications.

First isolation and whole-genome characterization of a G9P[14] rotavirus strain from a diarrheic child in Egypt.

An unusual group A rotavirus (RVA) strain (RVA/Human-tc/EGY/AS997/2012/G9[14]) was isolated for the first time in a faecal sample from a 6-month-old child who was hospitalized for treatment of acute gastroenteritis in Egypt in 2012. Whole-genome analysis showed that the strain AS997 had a unique genotype constellation: G9-P[14]-I2-R2-C2-M2-A11-N2-T1-E2-H1. Phylogenetic analysis indicated that the strain AS997 had the consensus P[14] genotype constellation with the G9, T1 and H1 reassortment. This suggests either a mixed gene configuration originated from a human Wa-like strain and a P[14]-containing animal virus, or that this P[14] could have been acquired via reassortment of human strains only. The study shows the possible roles of interspecies transmission and multiple reassortment events leading to the generation of novel rotavirus genotypes and underlines the importance of whole-genome characterization of rotavirus strains in surveillance studies.

Localized Multi-axis Loading Impact on Interconnect Thermal Cycling Performance in Via-in-Pad Plated Over (VIPPO) Board Configuration

The effects of different via pad configurations on solder joint reliability during thermal cycling have been investigated. Implementation of the via-in-pad plated over (VIPPO) design configuration induced additional loading conditions for each ball grid array interconnection, resulting in a lower than expected thermal cycling performance. Thermal cycling of memory components with 0.8-mm pitch and 300-μm-diameter solder joints with and without VIPPO configuration boards have been evaluated. It was identified that specific pad design parameters degraded the thermal cycling performance. Under thermal cycling, Printed circuit boards with all-VIPPO pads and all-dog-bone pads were found to have a higher thermal cycling performance than the unevenly distributed mixed VIPPO/dog-bone pad configuration. The characteristic life for the mixed VIPPO configuration shows a performance level of 56% compared to the all-dog-bone configuration and 44% compared to the all-VIPPO configuration. Electron backscattered diffraction images revealed straining within the solder joints stemming from tension and compression due to different via pad configurations. The laser profilometer height measurement showed that dog-bone pads have larger z-axis movement than VIPPO pads, inducing localized tension within the solder joints. The heating and cooling behavior observed for VIPPO and dog-bone via pads during thermal cycling induced localized tension and compression that exacerbated joint failure and accelerated their degradation. The temperature behavior of the different pads under thermal cycling suggests that thermal cycling is a complex multi-axis phenomenon.

Structural response of monolithic and multi-layered circular metallic plates under repeated uniformly distributed impulsive loading: An experimental study

A series of 112 experiments were conducted to investigate the response of monolithic and multi-layered metallic plates under repeated uniform impulsive loading up to five times. 15 various testing groups were considered to study the effects of different charge masses, layering configurations, layering arrangements, layer thicknesses, and stand-off distances on the central deflection of single-, double-, triple-layered and triple-layered mixed plates made of aluminum alloy and mild steel materials. The results showed that the triple-layered mixed configuration made of thick aluminum middle and front plates and thin mild steel plate has the best performance compared to other tested configurations from the 1st to 5th loading cycle while the triple-layered steel plate has the poorest performance at the 1st and 2nd loading cycle. Also, the triple-layered mixed configuration with thin mild steel back and front layers showed the poorest blast performance after the 2nd cycle. Additionally, empirical design formulae were proposed to predict the central deflection of monolithic and multi-layered plates under repeated impulsive loading based on new dimensionless numbers.

Stochastic Ionic Transport in Single Atomic Zero-Dimensional Pores.

We report on single atomic zero-dimensional (0D) pores fabricated using aberration-corrected scanning transmission electron microscopy (AC-STEM) in monolayer MoS2. Pores are comprised of a few atoms missing in the two-dimensional (2D) lattice (1-5 Mo atoms) of characteristic sizes from ∼0.5 to 1.2 nm, and pore edges directly probed by AC-STEM to map the atomic structure. We categorize them into ∼30 geometrically possible zigzag, armchair, and mixed configurations. While theoretical studies predict that transport properties of 2D pores in this size range depend strongly on pore size and their atomic configuration, 0D pores show an average conductance in the range from ∼0.6-1 nS (bias up to 0.1 V), similar to biological pores. In some devices, the current was immeasurably small and/or pores could not be wet. Furthermore, current-voltage (I-V) characteristics are largely independent of bulk molarity (10 mM to 3 M KCl) and the type of cation (K+, Li+, Mg2+). This work lays the experimental foundation for understanding of the confinement effects possible in atomic-scale 2D material pores and the realization of solid-state analogues of ion channels in biology.

Stochastic radiative transfer in random media: Pure absorbing cases.

We study stochastic radiation transport through random media in one dimension, in particular for pure absorbing cases. The statistical model to calculate the ensemble-averaged transmission for a binary random mixture is derived based on the cumulative probability density function (PDF) of optical depth, which is numerically simulated for both Markovian and non-Markovian mixtures by Monte Carlo calculations. We present systematic results about the influence of mixtures' stochasticity on the radiation transport. It is found that mixing statistics affects the ensemble-averaged intensities mainly due to the distribution of cumulative PDF at small optical depths, which explains well why the ensemble-averaged transmission is observed to be sensitive to chord length distribution and its variances. The effect of the particle size is substantial when the mixtures' correlation length is comparable to the mean free path of photons, which imprints a moderately broad transition region into the cumulative PDF. With the mixing probability increasing, the intensity decreases nearly exponentially, from which the mixing zone length can be approximately estimated. The impact of mixed configuration is also discussed, which is in line with previous results.