bluuebunny/crossref_metadata_2025_split huggingface dataset:
An improved cross-subject spatial filter transfer method for SSVEP-based BCI
Authors: Yan Wenqiang , Wu Yongcheng , Du Chenghang , Xu Guanghua 
Published: July 2022

Abstract

Objective. Steady-state visual evoked potential (SSVEP) training feature recognition algorithms utilize user training data to reduce the interference of spontaneous electroencephalogram activities on SSVEP response for improved recognition accuracy. The data collection process can be tedious, increasing the mental fatigue of users and also seriously affecting the practicality of SSVEP-based brain-computer interface (BCI) systems. Approach. As an alternative, a cross-subject spatial filter transfer (CSSFT) method to transfer an existing user data model with good SSVEP response to new user test data has been proposed. The CSSFT method uses superposition averages of data for multiple blocks of data as transfer data. However, the amplitude and pattern of brain signals are often significantly different across trials. The goal of this study was to improve superposition averaging for the CSSFT method and propose an Ensemble scheme based on ensemble learning, and an Expansion scheme based on matrix expansion. Main results. The feature recognition performance was compared for CSSFT and the proposed improved CSSFT method using two public datasets. The results demonstrated that the improved CSSFT method can significantly improve the recognition accuracy and information transmission rate of existing methods. Significance. This strategy avoids a tedious data collection process, and promotes the potential practical application of BCI systems.
Intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency biphasic stimulation
Authors: Zhong Yihua , Zhang Xu , Beckel Jonathan , de Groat William C , Tai Changfeng 
Published: July 2022

Abstract

Objective. A new axonal conduction model was used to analyze the interaction between intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS). Approach. The model includes intracellular and extracellular sodium and potassium concentrations and ion pumps. First, the HFBS (1 kHz, 5.4 mA) was applied for a duration (59.4 s) long enough to produce an axonal conduction block after terminating the stimulation, i.e. a post-stimulation block. Then, the intensity of HFBS was reduced to a lower level for 4 s to determine if the axonal conduction block could be maintained. Main results. The block duration was shortened from 1363 ms to 5 ms as the reduced HFBS intensity was increased from 0 mA to 4.1 mA. The block was maintained for the entire tested period (4000 ms) if the reduced intensity was above 4.2 mA. At the low intensity (<4.2 mA) the membrane potential oscillation disrupted the post-stimulation block caused by the increased intracellular sodium concentration, while at the high intensity (>4.2 mA) the membrane potential oscillation was strong enough to maintain the block and further increased the intracellular sodium concentration. Significance. This study indicates a possibility to develop a new nerve block method to reduce the HFBS intensity, which can extend the battery life for an implantable nerve stimulator in clinical applications to block pain of peripheral origin.
Comparison between MAST-U conventional and Super-X configurations through SOLPS-ITER modelling
Authors: Fil A. , Lipschultz B. , Moulton D. , Thornton A. , Dudson B.D. , Myatra O. , Verhaegh K. , the EUROfusion MST1 Team  
Published: July 2022

Abstract
MAST-U has recently started operating with a Super-X divertor, designed to increase total flux expansion and neutral trapping, both predicted through simple analytic models and SOLPS calculations to reduce the plasma and impurity density detachment thresholds. In this study, utilising the SOLPS-ITER code, we are quantifying the possible gain allowed by the MAST-U Super-X and neutral baffling geometry, in terms of access to detachment. We show that a significant reduction of the upstream density detachment threshold (up to a factor 1.6) could be achieved in MAST-U, for the Super-X, as opposed to conventional divertor geometry, mainly through an increased total flux expansion, neutral trapping being found very similar between the different configurations. We also show that variations of the strike-point angle are complex to interpret in such a tightly baffled geometry, and that a case in which the target normal points more towards the separatrix does not necessarily imply a lower detachment threshold. As in previous calculations for TCV, we quantify the role of neutral effects through developing and applying a quantitative definition of neutral trapping.
Wall stabilization of the rigid ballooning m = 1 mode in a long-thin mirror trap
Authors: Kotelnikov Igor , Zeng Qiusun , Prikhodko Vadim , Yakovlev Dmitri , Zhang Keqing , Chen Zhibin , Yu Jie 
Published: July 2022

Abstract
The prospect of stabilization of the m = 1 ‘rigid’ ballooning mode in an open axially symmetric long-thin trap with the help of a conducting lateral wall surrounding a column of isotropic plasma is studied. It was found that for effective wall stabilization, the beta parameter β must exceed some critical value β
crit. The dependence of β
crit on the mirror ratio, radial pressure profile, axial profile of the vacuum magnetic field, and the width of vacuum gap between plasma and lateral wall was studied. Minimal critical beta at the level of 70% is achieved at zero vacuum gap, although stability zone at β → 1 exists even at extremely wide vacuum gap. It is shown that when a conducting lateral wall is combined with conducting end plates simulating attachment of the end MHD stabilizers to the central cell of an open trap, there are two critical beta values and two stability zones that can merge, making stable the entire range of allowable beta values 0 < β < 1.
Design and optimization of a missile transporter semi-trailer structure
Authors: Ibrahim A M , Ali A M , Kamel H 
Published: July 2022

Abstract
Minimizing weight, maximizing strength, and maximizing stiffness are the three main challenges of designing semi-trailer structures. This paper presents the design and optimization process of a lightweight missile transporter semi-trailer chassis. The semi-trailer supports up to 40 tons of payload. The payload consists of three generic missiles with a standard length up to 12.5 m. The stacking of these missiles up-shifted the overall center of gravity. The high center of gravity endangered the safe maneuvering of the semi-trailer. The design process went through several iterations to meet the functional and installation requirements of the payload. A finite element model simulated the structure with respect to the loading conditions. Then, the model was implemented to formulate an optimization problem. The optimization objectives were to minimize the chassis weight and constrain the stress to an acceptable value at the same time while safely supporting the payload. The optimization problem solution successfully achieved a balanced trade-off between structural weight, stiffness, and rigidity. The new optimized design is approximately 12.6% lighter and 10.1% stiffer than the initial design for bending loads.
Analysis, control, and optimization of aeroelastic systems: an introduction to the recent literature for the new investigator
Authors: Kasem M M 
Published: July 2022

AbstractAeroelasticity studies the static and dynamic interaction between structural deformation and fluid forces. As a result, the aeroelasticity is usually divided into three parts: aerodynamics, structural response, and dynamics with statics as a special case. Instabilities may occur to this interaction (feedback) that lead to structural failure and, even when no instability occurs, the interaction may lead to degradation or improvement of the system performance. There are several unstable phenomena may occur for elastic bodies such as flutter, divergence, low cycle oscillation, buffet, and control surface reversal. These unstable phenomena can be classified as dynamic or static. The present work provides a tutorial for those newly encountering aeroelasticity and a review of the recent literature from this century (after 2000). This includes mathematical modelling and its applications to airplanes, rotor blades, energy harvesting, and the control, and optimization of aeroelastic systems. Recent research advances are summarized and some suggestions for future work are made.
An experimental study on the damping characteristics and tuning of the liquid column vibration absorber
Authors: Abou elenin M M , Younes Y K , Younes M F 
Published: July 2022

Abstract
This paper deals with an experimental investigation of the damping characteristics of the liquid column dynamic vibration absorber. The laboratory test rig of a single degree of freedom system integrated with a liquid column dynamic vibration absorber was designed and manufactured to study the efficiency of this type of dynamic absorbers. The system response has been measured and recorded by using a (DXL-345) accelerometer and data acquisition system. The effects of mass ratio, length ratio, and the opening ratio of the central orifice on the vibration reduction of the main structure in free vibration mode were evaluated. The results showed that the tuned liquid column vibration absorber has a good ability to reduce or eliminate unwanted vibration by the suitable selection of the combination of its design parameters. The maximum damping of the main system was achieved at the mass, length and orifice opening ratios equal to 7.7 %, 87% and 74% respectively.
Design, modeling, and manufacturing of dual-axis inertially stabilized platform
Authors: Ahmed K M , Roshdy A A , Kamel A M , Ata W G 
Published: July 2022

Abstract
A dual-axis inertially stabilized platform (DISP) was designed, modelled, and manufactured to control the pitch and yaw rotations continuously about Y and Z axes respectively for the purpose of tracking and observation of moving objects from a moving platform. The DISP structure consists of an inner gimbal that carries the payload (sensors) and revolves in the elevation direction about the trunnion -axis, and an outer gimbal that makes the cross-elevation rotation (azimuth). At first, 3D model of the DISP was constructed using the parametric computer-aided design (CAD) software. Then, to investigate the kinematic and dynamic performance of the systems under various excitations, A MATLAB model is generated. The designed model is optimized using CAD software to reduce and redistribute the DISP masses for better output of the model performance. The results show a small inertia effect due to the great reduction of masses of the inner and outer frames. In addition, the elevation and azimuth torques are also decreased.
An investigation of post-weld heat treatment of friction stir welded aluminium blanks AA2024 embedded with AA7075
Authors: Saad F , Ibrahem K , Abu-Okail M , Khairaldien W M , Allah M H 
Published: July 2022

Abstract
This article is focused main problem during and after FSW especially when joining blanks AA2024 embedded with interlayer strip widths AA7075, in microstructure of the welded zone, that will in turn affect its mechanical properties of the welded joints. So, a number of interlock strip widths of AA7075 as 1, 1.5, 2, 2.5 and 3 mm were added between two substrates of base metal AA2024 during FSW technique then followed heating and cooling procedures to incorporate into the heat treatment process, which is conducted to create changes in a material’s microstructure that will in turn affect its mechanical properties. The analyses by optical microscope and scanning electron microscope were used to clarify microstructural characterization of FSWed with interlock strip widths after PWHTed. On the other hand, the microhardness and tensile tests were performed to determine mechanical properties of FSWed with interlock strip widths after PWHTed. The observations of microstructural elucidated that the good bonding connection between interlayer strip widths AA7075 and base metal AA2024 was due to use the procedures of PWHT. The mechanical properties such as microhardness and tensile of produced joints with PWHTed were showed higher than without PWHTed. Specifically, the ultimate tensile strength, and hardness values of the post-heat joint when using 3mm interlayer strip were obtained the highest values 299MPa, 186 HV respectively. This presents improvement by 11.2% in tensile strength, and 84% in hardness, compared to as weld joint.
Tungsten carbide core 12.7x99 mm AP projectiles ballistic behavior against high hardness steel armor
Authors: Abdelsalam O R , Fayed A 
Published: July 2022

Abstract
This paper studies the ballistic behavior of developed 12.7x99mm armor-piercing (AP) projectiles with Tungsten Carbide Core. The development of AP projectiles aims to improve their penetration abilities against high-strength alloy steel targets. Different designs have been modeled in order to determine their penetration capabilities to choose the best design compared with that of traditional 12.7x99mm AP projectile. The study includes, the ballistic performance and stability of the newly developed bullets have been evaluated using PRODAS. Then, Numerical simulations in the environment of ANSYS have been carried out for the developed configurations as well as the traditional AP one to predict their penetration abilities. Finally and according to the PRODAS and simulation results, the designs with best results are chosen to be manufactured and tested by firing against ARMOX-500 steel alloy targets. The results show that the stability has been achieved and the penetration ability for one of the developed projectiles is more than traditional AP projectiles by 150%.
Quasi static compressive behavior of aluminum foam
Authors: Mysarh A M , shamekh M , Abdelshafy M H 
Published: July 2022

Abstract
Closed-cell AL foams’ indentation response under quasi-static loading and uniaxial compression at varied strain rates (from 3.333e-4 to 0.1333 s-1) were studied experimentally in this study. The indentation deformation was found to be nearly entirely contained inside a compressed zone within cap of spherical shape below the indenter. The strength due to indentation for aluminum foam with closed cell is higher than its uniaxial compressive strength due to effort needed in ripping cell walls along indenter circumference & friction. Under transverse uniaxial compressive stresses, the aluminum foam (closed cell type) shows an elastoplastic behavior. Metal foam is an excellent energy absorber, as seen by a long plateau Stress VS Strain curve. In contrast, plastic strength appears to grow linearly with strain rate, but metals with higher density appear having just a linear behavior. The sensitivity of foam to strain was shown to be dependent on strain and strain rate, just as that of metals with higher density.
An investigation of square opening process on a carbon fiber reinforced plastic composites by abrasive water jet
Authors: Edriys I I , Fattouh M 
Published: July 2022

Abstract
Because of the abrasive water jet (AWJ) contour-making process nature, the changing nozzle traverse direction involved in AWJ contouring results in shape errors. AWJ contouring appears to be an area that needs special attention. Accordingly, a detailed experimental investigation is presented in this work to study the various cutting performance measures in AWJ profile cutting (square opening) of carbon fiber reinforced plastic composites (CFRPCs) based on a statistically designed experimental investigation. Various major process variables (water pressure, nozzle traverse speed, standoff distance between the nozzle, workpiece thickness, and abrasive flow rate) are considered. Three quality characteristics of square namely square dimensional deviation, square taper angle, and corners error were selected to be optimized. The experimental data were subsequently used to develop predictive models for the major machining performance measures. The predictive empirical models (second-order polynomial) in conjunction with generalized reduced gradient (GRG) algorithm and desirability function are used for multi-response optimization of AWJ contouring. Some typical defects in the contoured cutting processes are presented and discussed.
The effect of using the WCO biodiesel as an alternative fuel in compression ignition diesel engine on performance and emissions characteristics
Authors: Elkelawy M , El Shenawy E A , Bastawissi H A E , El Shennawy I A 
Published: July 2022

Abstract
Recently, the need for using a substitute fuel for petroleum fuel in diesel engines becomes an utmost necessity, However, the petroleum fuel is considered a non-renewable source and has some environmental side effects. The price of petroleum fuels changes according to the world economic and political problems. Engine emissions should be reduced and fit the governmental guidelines, the harmful emissions produced from engines have extreme environmental side effects, one of these effects is called the global warming which causes a global increase in the world temperature. In this study, the biodiesel extracted from the Waste Cooking Oil (WCO) is generated as a substutute for the diesel fuel. In the process of the biodiesel production, catalytic transesterification reaction is used to change WCO to methyl esters by adding low alcohol concentration. The produced biodiesel will be prepared for using as a fuel blend along with the commercial diesel fuel and using it to petrol the four-stroke direct injection diesel engine without any modification to original fuel system. The engine will be tested experimentally with varying loads at fixed speed of 1400 rpm with a natural aspiration process, using blends of (B20 [is composed of 20% biodiesel and 80% diesel], B40 [is composed of 40% biodiesel and 60% diesel], B60 [is composed of 60% biodiesel and 40% diesel], B80 [is composed of 80% biodiesel and 20% diesel] and pure diesel). The effect of the use of different biodiesel blends has been investigated and tested on the performance of the engine and emissions. The experimental findings clarify that the diesel engine can be run with different blends of diesel and biodiesel at the same operating condition with decreasing brake thermal efficiency by 9.6 %, decreasing exhaust temperature by 7.6% and increasing brake specific fuel consumption by 16%.
Mathematical modeling of the gettering process for a cylindrical region
Authors: Kostikov Yu A , Romanenkov A M 
Published: July 2022

Abstract
The paper considers a mathematical model of the technical process of external gettering of silicon rods. The purpose of this process is to remove unwanted impurities from silicon. The model of this process is an initial-boundary value problem for a linear partial differential equation of parabolic type. A feature of this problem is the presence of a nonlocal in time boundary condition, which reflects the law of conservation of mass (matter). For numerical modeling, an algorithm based on difference approximations of differential operators of the 1st and 2nd order is proposed. The classical sweep method is used to find a solution to a discrete problem.
Numerical investigation of a near-wake flowfield with base bleed
Authors: Molchanov A M , Siluyanova M V 
Published: July 2022

Abstract
A computational study of a supersonic flow in the base region and the nearest wake of a cylindrical body moving at a supersonic speed has been carried out. In this case, the “prehistory” of the flow was taken into account, i.e. the configuration of the computational domain was as close as possible to the real one. The use of various RANS turbulence models for calculating flow in the base region and the nearest wake was analyzed. The following turbulence models were considered: 1) SST model; 2) Standard k–ε model; 3) k–ε RNG model; 4) Standard Reynolds Stress (RS) model; 5) RS BSL model. Based on a comparison of the calculation results with experimental data, it is shown that: 1) when calculating the flow in the base region and in the wake of the vehicle, it is very important to take into account the “prehistory” of the flow, i.e. to calculate the flow around the entire vehicle; 2) the best match was obtained using the the k–ε RNG model. The effect of base bleed on the near-wake flowfield of a cylindrical afterbody aligned with a Mach 2.5 flow has been investigated.
Numerical investigation of rotor-dynamic system on taking into account gas in labyrinth seals clearances
Authors: Cherepanov I E , Ya Modorskii V , Babushkina A V 
Published: July 2022

Abstract
To transport natural gas over long distances, it is necessary to build gas compressor stations that compensate for gas energy losses due to friction. The natural gas uninterrupted supply to consumers depends on their work reliability. The contemporary trend towards increase performance and a simultaneous decrease in structural rigidity lead to previously unpredictable compressor rotor oscillations. The article describes the primary causes of compressor rotor vibrations and some methods of dealing with them. Limitations of existing approaches are overcome by applying multiphysicsmodeling of a fluid and structure interaction using the 2FSI approach. Modeling performed for a labyrinth-seal compressor rotor model. ANSYS software product was chosen to solve the problem, which implements the 2FSI method. The modeling was carried out on a high-performance computer complex PNRPU. Trajectories of a point on the shaft rotation axis was analyze for the solid model. The numerical modeling results of the solid structure taking into account a gas dynamics are presented. The 2FSI calculation results are compared with the solid dynamic modeling results. An imbalance influence on the system dynamic is noted. The simulations 2FSI series were performed to study geometric, kinematic and gas-dynamic parameters influence on the rotor dynamic state. The maximum effect is exerted by an initial pressure in the seal gap. The rotor and gas oscillations resonant frequency was found, which corresponds to a change in the shaft axis spatial position in the 2FSI statement.
Characteristics of modified taro (Colocasia esculenta L. schott) flour from application of crude amylase enzyme filtrate of tempeh (Rhizopus oligosporus) mold
Authors: Wahyuni S , Khaeruni A , Asnani  , Sarinah  , Nurhamsia  , Dewi N D P 
Published: July 2022

AbstractThis study aimed to determine the effect of fermentation time and the enzyme activity of tempehR. oligosporusmold on the physicochemical characteristics of modified taro (Colocasia esculentaL. Schott) flour. This study used experimental design with incubation time of 3, 6, and 10 hours and enzyme activity of 1.48 U/mL and 3.43 U/mL. The characteristics of the taro flour studied included viscosity, swelling power, water solubility index, pH, proximate. The results of the study showed that the best incubation time was 6 hours and the enzyme activity was 3.43 U/mL. The characteristics of the selected modified taro flour compared to the control treatment showed a decrease in viscosity by 53.80% and in pH by 3.38%, an increase in swelling power by 3.34%, and solubility by 18.41%,. The proximate content of the selected modified taro flour showed that content increased : the water, ash, protein, and crude fiber by 16.87%, 15.21%, .24%, and 54.38% respectively. Otherwise the fat by 9.48% and carbohydrate by 20.12% was decreased. The results of this study showed an increase in the physicochemical characteristics of taro flour.