Influence Of Different Configurations Research Articles

The impact of S vacancies on the modulation of the work function and Schottky barrier at the Au/MoS2 interface

The S vacancy at metal/MoS2 interface plays a much important role than the semiconductor itself. In this work, the influence of different configurations of S vacancy concentrations on the effective work function and band structure of the Au/MoS2 interface has been investigated systematically using first-principles calculations. The study specifically explores the effective work function of the Au/MoS2 interface, the deviation of interface effects from the vacuum work function, and the dipole moment caused by interface charge transfer. The results reveal that the electronic work function of Au/MoS2 increases with the increase in S vacancy concentration, but the rate of increase tends to slow down with higher S concentrations. The variation in the effective work function of the Au/MoS2 interface may be attributed to the presence of S vacancies and the exposure of Mo atoms. S vacancies lead to a reduction in the Schottky barrier, resulting in increased leakage current. The Fermi pinning caused by S vacancy concentration and location is also observed. The results obtained in this study can serve as a theoretical foundation for applications in electronic devices that rely on metal/MoS2 contact.

Experimental and numerical study during the solidification process of a vertical and horizontal coiled ice storage system

Energy storage technology provides a solution to the contradiction between energy supply and demand, as well as the volatility and intermittency of renewable energy. As a representative energy storage system, the coil type energy storage system is of great significance in improving the reliability and cooling economy of building cooling systems. The configuration of coils has a significant impact on the ice storage process and icing rate. This study deals with the experimental and numerical analysis of the influence of different configurations on solidification process. The natural convection and density reversal at 277.15K of water have a significant impact during the cooling process. Therefore, we divide the cooling stage of water into two stages: 283.15K–277.15K and 277.15K–273.15K. Due to natural convection and density reversal of the cooling process, the thickness of the ice layer on the outer surfaces of the upper and lower sides varies unevenly in the horizontal configuration. The phenomenon where the ice layer in the vertical configuration is distributed conical, and the ice layer at the bottom is thinner than the ice layer at the top. As the ice storage process progresses, natural convection decreases from 1.5 × 10−2 m/s to 2.9 × 10−4 m/s. Within 210 min, the thickness of the ice layer in the vertical configuration is 2.27 mm thicker than that in the horizontal configuration. This article aims to study the effects of natural convection and density reversal during ice storage, explore the ice storage rate under horizontal and vertical placement, and provide reference value for practical engineering. To be conclusive, the ice storage rate of the vertical configuration increased by 13.33 % compared to the horizontal configuration.

Experimental assessment and prediction of design parameter influences on a specific vacuum-based granular gripper

Innovative soft robotic grippers, such as granular grippers, enable the automated handling of a wide spectrum of different geometries, increasing the flexibility and robustness of industrial production systems. Granular grippers vary in their design as well as in their configuration, which affects the specific characteristics and capabilities regarding grippable objects. Relevant aspects are the selection of granulates and membranes, as they affect the deformability. This influences the achievable gripping forces, which vary with the gripped objects geometry. On the basis of experimental studies, the modeling of interpolations as well as through experimental validations, the present research investigates the influences of different configurations on the achievable gripping forces for a specific concept of an innovative vacuum-based granular gripper. Specifically, the focus lies on design as well as configuration parameters, which could influence the achievable gripping force. Influencing parameters are determined based on a literature review of similar gripping concepts. Various adjustment possibilities are identified, such as materials of granulates or membranes. The possible configuration options are experimentally analyzed with a one-factor-at-a-time approach. The possibility of modelling the effects of their interrelations on the achievable gripping force is examined with approaches for linear models and compared to interpolations based on Machine Learning. Especially the granulate filling level and the membrane configuration exhibit the largest influences, which were best predicted with the approach based on artificial neural networks. A selection of an optimized gripper configuration for a specified object set as well as possible further developments such as a continuous expandability of the approaches and integrations with simulations are discussed. As a result of these analyses, this research provides methodologies for an optimized selection of a gripper configuration for an improved object-specific achievable gripping force and allows for more efficient handling processes with the examined type of vacuum-based granular gripper.

State of the Art in Development of Heat Exchanger Geometry Optimization and Different Storage Bed Designs of a Metal Hydride Reactor.

The efficient operation of a metal hydride reactor depends on the hydrogen sorption and desorption reaction rate. In this regard, special attention is paid to heat management solutions when designing metal hydride hydrogen storage systems. One of the effective solutions for improving the heat and mass transfer effect in metal hydride beds is the use of heat exchangers. The design of modern cylindrical-shaped reactors makes it possible to optimize the number of heat exchange elements, design of fins and cooling tubes, filter arrangement and geometrical distribution of metal hydride bed elements. Thus, the development of a metal hydride reactor design with optimal weight and size characteristics, taking into account the efficiency of heat transfer and metal hydride bed design, is the relevant task. This paper discusses the influence of different configurations of heat exchangers and metal hydride bed for modern solid-state hydrogen storage systems. The main advantages and disadvantages of various configurations are considered in terms of heat transfer as well as weight and size characteristics. A comparative analysis of the heat exchangers, fins and other solutions efficiency has been performed, which makes it possible to summarize and facilitate the choice of the reactor configuration in the future.

Influence of resistance due to locomotion mechanism configurations of a new high-speed amphibious vehicle (HSAV-Ⅱ)

Amphibious vehicles are capable of moving on both water and land, which makes their design more complex than that of ships. The locomotion mechanism of an amphibious vehicle is the main distinguishing feature from ships and is also the primary source of water resistance. The resistance characteristics of amphibious vehicles with different locomotion mechanisms are mainly studied in this paper. Firstly, a numerical calculation method based on the RANS method is established and verified by experiments. Secondly, the resistance characteristics of the amphibious vehicle under a series of speeds are analyzed, and the importance of reducing pressure resistance is demonstrated. Then, the resistance characteristics of different amphibious vehicle configurations are compared. Hull 1 has the smallest resistance at low speed, with a maximum resistance reduction rate of 9.3%; Hull 3 has the best performance at high speed, with a maximum resistance reduction rate of 12.5%. The influence of different configurations is analyzed from the perspectives of the flow field, vehicle attitude, and pressure distribution. Finally, the resistance values and their proportion of total resistance acting on different locomotion mechanisms are analyzed. The results show that the resistance at low speed is related to the complexity of the surface, and the resistance at high speed is more dependent on the attitude. The conclusions of this study have guiding significance for the design of high-speed amphibious vehicles.

Influence of different configurations of western North Pacific anticyclone and Siberian high on spring climate over China

AbstractThis study analyses the spring climate anomalies under different configurations of western North Pacific anticyclone (WNPA) and Siberian high (SH). Compared to the WNPA alone with increased precipitation over southern China, the out‐of‐phase configuration (strong‐WNPA–weak‐SH) can enhance the WNPA‐related southwesterlies over eastern China, favouring increased precipitation with larger amplitude over southern China and southern Northeast China. Differently, the in‐phase configuration (strong‐WNPA–strong‐SH) decreases and confines WNPA‐related southwesterlies over southern China, causing decreased precipitation over eastern Southwest China; additionally, the WNPA‐related southwesterlies converge with SH‐related northwesterlies over the lower reaches of the Yangtze River, causing increased precipitation there. For surface air temperature, the WNPA alone induces warming over western Southwest China through changing heat flux, while the SH alone induces cooling over northern China through changing temperature advection, and over Northwest and southern China through changing heat flux. In the out‐of‐phase configuration, warming expands into Northern China due to the cooperation of weakening SH. In the in‐phase configuration, SH‐related cooling mainly occurs to the north of the Yangtze River because of the obstruction of WNPA. Further analysis indicates the eastern Pacific (EP) and central Pacific (CP) El Niño‐Southern Oscillation (ENSO), European low and Ural high contribute to the different configurations of WNPA and SH. The EP ENSO‐related zonal overturning circulation intensifies the WNPA and European low‐induced warm advection weakens the SH, resulting in the out‐of‐phase configuration. The CP ENSO‐related zonal overturning circulation intensifies the WNPA with a northeast–southwest tilt and Ural high‐induced cold advection intensifies SH, resulting in the in‐phase configuration.

Spectro-spatial analysis of elastic wave propagation in nonlinear elastic metamaterial systems with damping.

Different from the linear counterpart, elastic wave propagation in nonlinear elastic metamaterials with damping (EMD) systems has much more novel behaviors. It is little work that reveals the nonlinear wave propagation mechanism in the nonlinear EMD in the literature. In this paper, nonlinear EMD systems with different configurations for the nonlinear elements are constructed to study the nonlinear wave propagation characteristics based on the analytical formulation. Nonlinear wave propagation attenuation characteristics in nonlinear EMD systems are studied in the frequency-domain. Spectro-spatial characteristics of nonlinear traveling wave packet in space- and time-domain are also analyzed to reveal space frequency-domain characteristics. Influences of different configurations for the nonlinear elements on wave propagation in nonlinear EMD systems are discussed. Results shown that locations of band structures can be tuned by changing intensities of nonlinearities in the nonlinear EMD systems, which are not found in the linear system. Moreover, different configurations for the nonlinear elements can lead to localization feature emerged in a nonlinear EMD system, which indicates solitary waves causing from the interaction between dispersion and nonlinearity exist in the nonlinear systems. This interesting wave propagating properties can be used to design new devices for acoustic switches, energy harvesting, and broadband vibration control.

Study on a novel reactive internally heat integrated distillation process for the synthesis of ethyl acetate and its column configuration

The production of ethyl acetate (EA) by reactive distillation (RD) has the disadvantage of high energy consumption. In order to solve this problem, the application of reactive internal heat integrated distillation was explored on the basis of RD process, and energy saving was further realized. The influence of different configurations of reactive internally heat integrated distillation column (RHIDiC) on the process were also studied. In this study, the symmetrical reaction internal heat integrated distillation column (S-RHIDiC), the upper aligned reaction internal heat integrated distillation column (UA-RHIDiC) and the lower aligned reaction internal heat integrated distillation column (LA-RHIDiC) were compared with RD in economic benefits, environmental protection, energy saving performance, and thermodynamic efficiency. In addition, all processes were optimized with TAC as the economic indicator. The results showed that S-RHIDiC process has the optimal economic benefits, environmental performance, energy consumption and thermodynamic efficiency. Compared with RD, the total annual cost (TAC) of S-RHIDiC was reduced by 32.56%, CO2 emissions were reduced by 52.79%, the TEC was reduced by 29.37%. The thermodynamic efficiency of RD, S-RHIDiC, UA-RHIDiC and LA-RHIDiC processes were 6.71%, 9.12%, 6.75% and 6.8%, respectively.

Calibration of focus-adjustable cameras for triangulation sensors by model-based camera parameter estimation

Abstract The working range of triangulation-based measuring systems is often limited by the depth of field of the applied optical system. Approaches such as increasing the depth of field range by reducing the aperture are limited in their effectiveness by a lower light yield and thus require a longer exposure time. Focus adjustable optics enable the depth of field to be modified and thus effect the location and shape of the working range. However, the validity of the model-based camera calibration is limited to the corresponding focus setting, especially with optics that exhibit the effect of focus breathing, i. e. whose focal length change with the focus setting. This paper presents an approach to model the calibration parameters over the entire focus range of a lens using function fitting of the camera parameters and the influence of different configurations on this process is examined.

Effect of Different Configurations on Bubble Cutting and Process Intensification in a Micro-Structured Jet Bubble Column Using Digital Image Analysis

An experimental study was conducted in this work to investigate the effect of different configurations on bubble cutting and process intensification in a micro-structured jet bubble column (MSJBC). Hydrodynamic parameters, including bubble size, flow field, liquid velocity, gas holdup as well as the interfacial area, were compared and researched for a MSJBC with and without mesh. The bubble dynamics and cutting images were recorded by a non-invasive optical measurement. An advanced particle image velocimetry technique (digital image analysis) was used to investigate the influence of different configurations on the surrounding flow field and liquid velocity. When there was a single mesh and two stages of mesh compared with no mesh, the experimental results showed that the bubble size decreased by 22.7% and 29.7%, the gas holdup increased by 5.7% and 9.7%, and the interfacial area increased by more than 34.8% and 43.5%, respectively. Significant changes in the flow field distribution caused by the intrusive effect of the mesh were observed, resulting in separate liquid circulation patterns near the wire mesh, which could alleviate the liquid back-mixing. The mass transfer experiment results on the chemical absorption of CO2 into NaOH enhanced by a mass transfer process show that the reaction time to equilibrium is greatly reduced in the presence of the mesh in the column.

Hysteretic behavior of replaceable steel plate damper for prefabricated joint with earthquake resilience

Prefabricated structures are widely used in civil infrastructure, attributed to the advantages of environmental sustainability, easy in-situ operation, short construction period and low-cost. Beam-to-column connection is the critical component for the structural integrity of prefabricated structures, and the failure of beam-to-column connection might lead to structural progressive collapse under earthquakes. In this paper, a novel dual-functional replaceable steel plate damper was proposed for prefabricated beam-to-column joints to improve the mechanical behavior and earthquake resilience. The influence of different configurations for steel plate damper on the hysteretic behavior was analyzed experimentally and numerically. Results obtained from experimental and numerical research demonstrated that proposed steel plate damper successfully developed desired mechanical behavior. Moreover, the influence of different configuration details including width-to-thickness ratio of steel plates, weakened length and width of steel plates, gap between weakened steel plates and constrained steel sleeves, were investigated to optimize the mechanical behavior of steel plate damper, and the favorable construction configurations were recommended based on parametric analysis. In the end, the hysteretic constitutive model for steel plate damper was proposed based on considerable numerical analysis on FEA models and verified by means of comparisons between theoretical results, experimental results and numerical analysis.

Influence of different configurations of Fe nanoparticles on the melting point: a molecular dynamics simulation

Influence of different configurations of Fe nanoparticles on the melting point: a molecular dynamics simulation

Design of a Flexible Capture Mechanism Inspired by Sea Anemone for Non-cooperative Targets

Robotic grippers have been used in industry as end-effectors but are usually limited to operations in pre-defined workspace. However, few devices can capture irregularly shaped dynamic targets in space, underwater and other unstructured environments. In this paper, a novel continuum arm group mechanism inspired by the morphology and motions of sea anemones is proposed. It is able to dissipate and absorb the kinetic energy of a fast moving target in omni-direction and utilize multiple arms to wrap and lock the target without accurate positioning control. Wire-driven actuation systems are implemented in the individual continuum arms, achieving both bending motion and stiffness regulation. Through finite element method, the influence of different configurations of the continuum arm group on the capture performance is analyzed. A robotic prototype is constructed and tested, showing the presented arm group mechanism has high adaptability to capture targets with different sizes, shapes, and incident angles.

Lightweight End-to-End Speech Enhancement Generative Adversarial Network Using Sinc Convolutions

Generative adversarial networks (GANs) have recently garnered significant attention for their use in speech enhancement tasks, in which they generally process and reconstruct speech waveforms directly. Existing GANs for speech enhancement rely solely on the convolution operation, which may not accurately characterize the local information of speech signals—particularly high-frequency components. Sinc convolution has been proposed in order to allow the GAN to learn more meaningful filters in the input layer, and has achieved remarkable success in several speech signal processing tasks. Nevertheless, Sinc convolution for speech enhancement is still an under-explored research direction. This paper proposes Sinc–SEGAN, a novel generative adversarial architecture for speech enhancement, which usefully merges two powerful paradigms: Sinc convolution and the speech enhancement GAN (SEGAN). There are two highlights of the proposed system. First, it works in an end-to-end manner, overcoming the distortion caused by imperfect phase estimation. Second, the system derives a customized filter bank, tuned for the desired application compactly and efficiently. We empirically study the influence of different configurations of Sinc convolution, including the placement of the Sinc convolution layer, length of input signals, number of Sinc filters, and kernel size of Sinc convolution. Moreover, we employ a set of data augmentation techniques in the time domain, which further improve the system performance and its generalization abilities. Compared to competitive baseline systems, Sinc–SEGAN overtakes all of them with drastically reduced system parameters, demonstrating its effectiveness for practical usage, e.g., hearing aid design and cochlear implants. Additionally, data augmentation methods further boost Sinc–SEGAN performance across classic objective evaluation criteria for speech enhancement.

Design and analysis of piezoelectric micromachined ultrasonic transducer using high coupling PMN-PT single crystal thin film for ultrasound imaging

Due to its higher frequency, improved impedance matching, and easy formation of array, piezoelectric micromachined ultrasonic transducer (PMUT) has drawn much attentions for application in ultrasound imaging. In this paper, PMUT based on [011] poled 0.70Pb(Mg1/3Nb2/3)O3–0.30PbTiO3 (PMN-0.30PT) single crystal thin film was proposed and modeled by performing finite element method. Influences of different configurations of top electrode shape and bottom cavity shape on PMUT performance were studied. The investigation results show that the resonant frequency of PMN-PT-based PMUT with circular top electrode and square bottom cavity is up to 27.155 MHz. The effective electromechanical coupling coefficient ( of PMUT was up to 2.32%, which was 127% larger than that of lead zirconate titanate-based PMUT. The static transmitting sensitivity was three times enhancement compared to PMUT with square top electrode and square bottom cavity. Furthermore, acoustic field characteristics of PMUT and PMUT arrays based on PMN-PT in water were investigated. The relative pulse-echo sensitivity level of 2 × 2 PMUT array was −35 dB with the reflector at 200 μm. The obtained results demonstrated that the proposed PMN-PT-based PMUT can achieve high frequency and large as well as considerable sensitivity, which is promising for application in high resolution ultrasound imaging.

Rational design of ultrahigh loading metal single-atoms (Co, Ni, Mo) anchored on in-situ pre-crosslinked guar gum derived N-doped carbon aerogel for efficient overall water splitting

Rationally designing single-atom catalysts (SACs) is a potential strategy to reach efficient energy conversion as they combine the merits of both maximizing atomic utilization and minimizing the cost of the heterogeneous catalysts. However, when increasing the loading capacity of single-atoms, how to effectively prevent the aggregation of metal single atoms to achieve higher atom utilization efficiency is an urgent issue. Herein, we develop an in-situ pre-crosslinking method to prepare a series of metal single-atoms anchored on nitrogen-doped carbon aerogel (M-SA@NCA, M = Co, Ni, Mo) as high-efficiency bifunctional catalysts for hydrogen/oxygen evolution reactions (HER/OER). Thanks to theintrinsic chemical crosslinking ability between the metal ions and the substrate functional groups, these metal single-atoms can be effectively and stably anchored in the three-dimensional network as crosslinked point of the substrate, thus endowing M-SA@NCA with ultrahigh single-atom loading (Co, ~27.30 wt%; Ni, ~18.35 wt%; Mo, ~18.16 wt%), and therefore display more active sites, and excellent stability (up to 100 h for water-splitting in 1.0 M KOH). Furthermore, the systematic X-ray absorption fine structure (XAFS), in-situ attenuated total internal reflection (in-situ ATR spectra) and density functional theory (DFT) calculation are used to acquire deep insight on the bonding modes between metal single-atoms and substrates, and the influence of different configuration on the catalytic performance. The combined results reveal that Co atoms facilitate the formation of pyrr-N, and the optimal configuration is CoN4 in HER process with smallest onset potential of 12.5 mV, closing to the Pt/C (20 wt%); while the best OER catalyst is Ni-SA@NCA with NiC2N2-o-5 moieties, outperforming the benchmarked IrO2. This work provides a solution for investigating the interaction between single-atom-substrate configuration and catalytic performance, and represents a critical step towards the rational design and synthesis of SACs with extremely high single-atom loading, maximum atomic utilization efficiency and thus superior catalytic activity.

Impact of discharge port configurations on the performance of sliding vane rotary compressors with a rotating cylinder

With the increasing requirements of compressed gas energy storage systems for compressors and expanders, sliding vane rotary compressors are worth trying. To study the influence of different configurations of discharge ports on the performance of compressors, numerical simulations are conducted on the innovative sliding vane compressors with a rotating cylinder. The reliable Renormalization Group k-ε turbulent model is adopted in Fluent 2020R1. The results show that as the coverage angle increases, the averaged mass flow rates increase, the averaged exhaust gas temperature decreases and the leakage between the rotor and rotating cylinder and at sliding vane tips decrease. When the coverage angle increases from 15° to 45° at the central position angle of −28°, the volumetric efficiency increases from 89.38% to 92.65% while the isentropic efficiency increases from 76.43% to 86.19%. When the central position angles range from −28°, −23° to −18° at the coverage angle of 30°, the farther the discharge port is to the narrowest gap between the rotor and cylinder, the lower the outlet temperature, the less the leakage flow, and the higher the isentropic efficiency. The scheme with the central angle of −28° and coverage angle of 45° is recommended as the best one.

Research on the configuration of cable-driven parallel robots for vibration suppression of spatial flexible structures

Specific satellites with ultra-long wings easily suffer from violent vibrations caused by the external disturbance and self-rotation, which do harm to flexible wings and affect the normal operation of satellites. In severe cases, the satellites would be damaged. Therefore, achieving rapid vibration suppression is particularly critical. Besides, to protect flexible wings from damage and reduce energy consumption, the control force should be small. Considering the above two issues comprehensively, a scheme using cable-driven parallel robots (CDPRs) to suppress vibrations is proposed. Furthermore, the influence of different configurations of CDPRs on the control effect is studied in the paper. First, the dynamic model of the CDPR which is comprised of four cables and a flexible structure is established using the finite element method. Then, the dynamic behavior of the model under the controllable cable force is analyzed by the Newmark-β method. An optimization index including the settling time, the maximum cable force and energy consumption is presented. Based on the index, six kinds of CDPRs with different configurations are tested under the control of the proposed Fuzzy-PID method and an active control method, respectively. As a comparison, a passive control scheme is also tested. Finally, numerical simulations are implemented to evaluate the effect of the vibration suppression, and the results are satisfactory.

Influence of different merging angles of pedestrian flows on evacuation time

The growing number of fires and other types of catastrophes occurring at large events highlights the need to rethink safety concepts and also to include new ways to optimize buildings and venues where events are held. Although there have been some attempts to model and simulate the movement of pedestrian crowds, little knowledge has been gathered to better understand the impact of the built environment and its geometric characteristics on the crowd dynamics. This paper presents computer simulations about pedestrians’ crowd dynamics that were conducted based on the Social Force Model. The influence of different configurations of pedestrian flows merging during emergency evacuations was investigated. In this study, 12 designs with different merging angles were examined, simulating the evacuation of 400 people in each scenario. The Planung Transport Verkehr (PTV, German for Planning Transport Traffic) Viswalk module of the PTV Vissim software (PTV Group, Karlsruhe, Germany) program was adopted, which allows the employment of the Social Force approach. The results demonstrate that both symmetric and asymmetric scenarios are sensitive to the angles of convergence between pedestrian flows.

Numerical investigation of the effect of different layers configurations on the performance of radial PEM fuel cells

This paper investigates the influence of different configurations of catalyst (CL), gas diffusion (GDL) and membrane on the performance of the radial flow field fuel cell. To this end, three different radial flow configurations were studied for the first time namely: radial with four channels (R4C), radials with two channels and horizontal MEA (R2CH) and radial with two channels and vertical MEA (R2CV) along with the conventional base fuel cell. Numerical simulations were undertaken for the equal active areas, geometric and boundary conditions including relative humidity and mass flow rates for the cathode and anode sides in all of the configurations. Examining the results of polarization curves, power density and net power demonstrated that the performance of the radial flow fuel cell can be improved significantly without obligating additional cost and only through selecting proper configuration of layers. For instance, the R4C case increases the net power of the fuel cell by 42% compared to the base model, while the R2CV case leads to a power loss by 8% compared to the base model. The results of this work can be adopted to improve the performance of various types of the PEM fuel cells through variation of the layers configuration.