bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the linear and nonlinear optical responses of few-layer exfoliated MoS2 and WS2 nanoflakes: experimental and simulation studies
Authors: Abhijith T , E Shiju , Suthar Rakesh , Sharma Punit , Thomas Sheenu , Karak Supravat
Published: July 2022

Understanding the linear and nonlinear optical (NLO) responses of two-dimensional nanomaterials is essential to effectively utilize them in various optoelectronic applications. Here, few-layer MoS2 and WS2 nanoflakes with lateral size less than 200 nm were prepared by liquid-phase exfoliation, and their linear and NLO responses were studied simultaneously using experimental measurements and theoretical simulations. Finite-difference time-domain (FDTD) simulations confirmed the redshift in the excitonic transitions when the thickness was increased above 10 nm indicating the layer-number dependent bandgap of nanoflakes. WS2 nanoflakes exhibited around 5 times higher absorption to scattering cross-section ratio than MoS2 nanoflakes at various wavelengths. Open aperture Z scan analysis of both the MoS2 and WS2 nanoflakes using 532 nm nanosecond laser pulses reveals strong nonlinear absorption activity with effective nonlinear absorption coefficient (β
eff) of 120 cm GW−1 and 180 cm GW−1, respectively, which was attributed to the combined contributions of ground, singlet excited and triplet excited state absorption. FDTD simulation results also showed the signature of strong absorption density of few layer nanoflakes which may be account for their excellent NLO characteristics. Optical limiting threshold values of MoS2 and WS2 nanoflakes were obtained as ∼1.96 J cm−2 and 0.88 J cm−2, respectively, which are better than many of the reported values. Intensity dependent switching from saturable absorption (SA) to reverse SA was also observed for MoS2 nanoflakes when the laser intensity increased from 0.14 to 0.27 GW cm−2. The present study provides valuable information to improve the selection of two-dimensional nanomaterials for the design of highly efficient linear and nonlinear optoelectronic devices.
Phase change and order 2 averaging for one-frequency systems with separatrix crossing*
Authors: Neishtadt Anatoly , Okunev Alexey
Published: July 2022

We study the evolution of angular variable (phase) for general (not necessarily Hamiltonian) perturbations of Hamiltonian systems with one degree of freedom near separatrices of the unperturbed system. To this end, we use the averaged system of order 2. We obtain estimates for the accuracy of the order 2 averaged system near separatrices and use these estimates to prove a formula for the phase change when solutions of the perturbed system approach separatrices of the unperturbed system (such formula is known when the perturbation is Hamiltonian). As an application of this formula, we show that two natural definitions of probability of capture into different domains after separatrix crossing proposed by Arnold and Anosov lead to the same formula for this probability.
Simulation study of a novel vertical GaN-based FS-IGBT
Authors: Wang Kai , Shangguan Shaofei , Zhang Peng , Liu Shuang , Li Mengdi , Ma Xiaohua , Hao Yue
Published: July 2022

In this paper, a novel GaN-based field stop-insulated gate bipolar transistor (FS-IGBT) is designed, which combines GaN-based Fin-MOS with the conventional material FS-IGBT, and the static and dynamic electrical characteristics of the device are simulated by Silvaco. The results show that the structure has a high saturation current (I
on,sat) density of 155 kA cm−2 at 10 V gate voltage (V
ge), an on-state voltage (V
on) of 3.5 V, a breakdown voltage (BV) of 1650 V, and a switching speed of nanoseconds. The characteristics of the device are analyzed and compared with Fin-MOS. The results demonstrate that the vertical GaN-based device can display both high current density and high BV due to the FS layer that adjusts the electric field distribution in the N-drift region. The paper also analyzes the selection of device parameters and feasibility of device manufacturing based on the existing material growth method and device manufacturing technology.
Resonant-type inertial impact linear piezoelectric motor based on coupling of driving and clamping parts
Authors: He Liangguo , Li Kun , Yan Yi , Wang Yong , Xiao Feiyun , Ge Xinfang , Gao Guangjie , Shan Zengxiang , Dou Haotian
Published: July 2022

A resonant-type inertial impact linear piezoelectric motor based on coupling of driving and clamping parts was designed and manufactured. The motor mainly includes stator (coupling of driving and clamping parts), mover (slider) and auxiliary parts. The driving part works in the resonant state under the excitation of single harmonic, which mainly realizes the function of reciprocating driving. Similarly, under the single harmonic driving, the clamping part also works in the resonant state to realize the clamping function. Through the coupling between the two parts of the stator, the mover is driven to move continuously in one direction. The inertial impact piezoelectric motor works in the resonant state because the driving and clamping parts work in the resonant state respectively. Compared with the traditional quasi-static inertial impact motor, this study novelly changes the working state of the inertial impact motor. Through the finite element simulation software COMSOL 5.2, the resonant frequency coupling of the driving and the clamping part is consistent. An experimental platform was built to verify the feasibility of the principle by testing the motor prototype. The experiment results show that: The maximum speed reaches 78 mm s−1 when the motor prototype is operated at the frequency of 810 Hz with a preload of 2 N and the working voltages of clamping and driving parts of motor were set at 80 and 220 Vp-p respectively. Meanwhile, the maximum load of the motor prototype can reach 5 N. The minimum resolution of the motor prototype is 6.379 μm.
Guided waves based damage localization based on mode filtering using fiber Bragg grating sensors
Authors: Soman Rohan , Radzienski Maciej , Kudela Pawel , Ostachowicz Wieslaw
Published: July 2022

Fiber Bragg grating (FBG) sensors have long been thought of as the ideal sensors for structural health monitoring (SHM) due to their small size, light weight, ability to be embedded and ability to be multiplexed. So, FBG sensors have been commonly used for strain based SHM. Their use for ultrasonic guided wave (GW) measurements in the traditional wavelength division multiplexing approach was tried as well, but did not get accepted widely due to the low sensitivity. In the recent times, a renewed interest is seen in the use of FBG sensors for GW measurements using the edge reflection approach which increases the sensitivity several folds. This paper reports a very interesting phenomena, shown by the FBG sensors. The mechanism of the measurement of the incident GW is different based on the relative ratio of the wavelength of the incident GW (

λ

G
W

) and the grating length (L) of the FBG sensor. For

λ

G
W

/

L
≫

 1 the propagating wave leads to uniform strain over the FBG resulting in the shift of the Bragg wavelength. For the

λ

G
W

/

L
≈

 1 the FBG experiences non-uniform strain over the FBG which results in the distortion of the spectrum (widening or narrowing) of the peak. By separating these effects on the FBG, mode filtering may be achieved. The mode-filtered data is then used for damage detection and damage localization. Modifications have been proposed to the elliptical approach which makes use of the filtered modes and removes the unwanted peaks in the signal stemming from the other mode. The methodology is validated on a simple aluminum plate with simulated damage scenarios (added mass). The results indicate that indeed the mode-filtered signals improve the damage localization performance of the actuator-sensor network.
Multi-GeV cascaded laser wakefield acceleration in a hybrid capillary discharge waveguide
Authors: Qin Zhiyong , Li Wentao , Liu Jiaqi , Liu Jiansheng , Wang Wentao , Yu Changhai , Zhang Zhijun , Wang Xinliang , Li Jinfeng , Leng Yuxin , Liang Xiaoyan , Li Ruxin , Xu Zhizhan
Published: July 2022

Based on a 6 cm-long two-segment hybrid capillary discharge waveguide, a multi-GeV electron beam with energy up to 3.2 GeV and 9.7% rms energy spread was achieved in a cascaded laser wakefield acceleration scheme, powered by an on-target 210 TW laser pulse. The electron beam was trapped in the first segment via ionization-induced injection, and then seeded into the second segment for further acceleration. The long-distance stable guiding of the laser pulse and suppression of the dark current inside the second-segment capillary played an important role in the generation of high-energy electron beams, as demonstrated by quasi-three-dimensional particle-in-cell simulations.
Coherent control of extreme ultraviolet emission generated through frustrated tunneling ionization
Authors: Kim Yang Hwan , Yun Hyeok , Hwang Sung In , Ivanov Igor A , Nam Chang Hee , Kim Kyung Taec
Published: July 2022

Coherent extreme ultraviolet (EUV) line emissions can be generated from an atom excited through frustrated tunneling ionization (FTI). The phase variation of the EUV emission in a generation medium along the propagation direction is a critical parameter that determines the phase-matching condition of this new light source. Here we show that the EUV emission sensitively depends on the intensity and phase of a driving laser pulse and the target position. Angle-resolved EUV spectra measured at different target positions and the carrier-envelope phases of the laser pulse exhibit an intensity modulation, showing similar behavior to that of a long-trajectory high harmonic radiation. The four-step model developed for the FTI emission accurately describes the coherent control of the EUV emission. These findings are essential ingredients for developing coherent extreme ultraviolet sources with high photon flux and for utilizing the FTI emission in time-resolved spectroscopy.
A scenario for high-temperature excitonic insulators
Authors: Yang Huaiyuan , Wang Xinqiang , Li Xin-Zheng
Published: July 2022

While excitonic insulators (EIs) have been intensively studied, proper platforms of them with stable lattice and non-cryogenic T
C are rare. By analysing their Bardeen–Cooper–Schieffer-like gap equation, we propose that high T
C EIs can exist in small indirect band gap 2D materials. After screening 2D transition-metal dichalcogenides from existing computational works, we select 2H-TiTe2 and 1T-PdTe2, and show that their T
C can be as high as 150 to 200 K under strains. A transition of their condensate EI state from that composed by Wannier excitons to that composed by plasmonic ones exists, even if negligible changes are reflected by the EI band structures, demonstrating the rich quantum feature of these systems. The high T
C also implies that they are ideal platforms for the demonstration and applications of EIs and their related quantum states in non-cryogenic environments.
Observational constraints on the massive neutrinos induced late-time cosmic acceleration
Authors: Sharma Mohit K , Pacif Shibesh Kumar Jas , Myrzakul Shynaray , Shanina Zamzagul
Published: July 2022

We investigate a late-time cosmological scenario at the both cosmological background and linear perturbative level which is based on a mass-less λ
ϕ
4 theory in which the scalar field is inextricably coupled to massive neutrino matter with Z
2 symmetry by a well defined conformal coupling. The chosen coupling generically leads to the spontaneous symmetry breaking at late times, as the coupling builds up dynamically, such that the field acquires a non-zero mass proportional to the neutrino mass and rolls down slowly around the true ground state which emerges after spontaneous symmetry breaking. From our parametric estimations, we find the given scenario is well supported by the background level cosmological observations and is also in a good agreement with the evolution of growth of matter perturbations.
An improved cross-subject spatial filter transfer method for SSVEP-based BCI
Authors: Yan Wenqiang , Wu Yongcheng , Du Chenghang , Xu Guanghua
Published: July 2022

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

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

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

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

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

Aeroelasticity 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

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

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

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

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

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

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

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

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

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

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

This 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.
Effect of various poultry feather hydrolysates on the growth of indigenous keratinolytic strains
Authors: Fitriyanto N A , Ramadhanti Y , Rismiyati  , Rusyadi I , Pertiwiningrum A , Prasetyo R A , Erwanto Y
Published: July 2022

Feather waste is a poultry by-product that is abundant, difficult to degrade, and creates an environmental problem. Feather protein is mainly composed of keratin, a structural protein with low digestibility. The effect of poultry feather meal prepared by NaOH as a Nitrogen source on the growth of the indigenous keratinolytic strain in the agar and the liquid medium was evaluated in this research. This study shows that all strains (Pseudomonas sp. PK-4, Bacillus cereus TD5B, and Bacillus cereus LS2B) can grow and produce clear zones around the colony. Medium containing 1% skim milk, commercial keratin, kampung, layer chicken feathers, and goose feathers were used to indicate that all strains could produce extracellular casein and keratinase enzymes. The strains can grow optimally in a liquid medium with feather hydrolysates, indicated by the increased turbidity (OD600) with a higher absorbance value. The highest growth occurred when strains grew with kampung chicken feather hydrolysate. Therefore, it can be concluded that the feather meals from local poultry feathers had potential as N-source for bacterial growth.
The Dyadic Interplay Between Relationship Satisfaction, Perceived Positive and Negative Social Control, and a Reduction of Sedentary Behavior Time
Authors: Siwa Maria , Szczuka Zofia , Banik Anna , Kulis Ewa , Boberska Monika , Wietrzykowska Dominika , Knoll Nina , DeLongis Anita , Knäuper Bärbel , Luszczynska Aleksandra
Published: July 2022

Background

Both the close relationship processes and health model and the dyadic health influence model posit that beliefs about the relationship (e.g., relationship satisfaction) and influence strategies (e.g., social control) serve as mediators of health behavior change. The evidence for such mediation is limited.

Purpose

This study investigated two competing hypotheses that arise from these models: (1) perceived use of positive and negative social control (attempts to influence the partner’s behaviors) predict sedentary behavior (SB) indirectly, via relationship satisfaction; or (2) relationship satisfaction predicts SB indirectly, via positive and negative social control.

Methods

Data from 320 dyads (target persons and their partners, aged 18–90 years), were analyzed using mediation models. SB time was measured with GT3X-BT accelerometers at Time 1 (T1; baseline) and Time 3 (T3; 8 months following baseline). Relationship satisfaction and social control were assessed at T1 and Time 2 (T2; 2 months following baseline).

Results

Higher T1 relationship satisfaction among target persons predicted target persons’ reporting of higher T2 negative control from partners, which in turn predicted lower T3 SB time among target persons. Lower T1 relationship satisfaction among partners predicted target persons’ reporting of higher T2 perceived negative control from partners, which predicted lower T3 SB time among target persons. On average, both members of the dyad reported moderate-to-high relationship satisfaction and low-to-moderate negative control.

Conclusions

In contrast to very low levels of negative control, its low-to-moderate levels may be related to beneficial behavioral effects (lower SB time) among target persons reporting moderate-to-high relationship satisfaction.
Development and Validation of a Two-component Perceived Control Measure
Authors: Lithopoulos Alexander , Zhang Chun-Qing , Williams David M , Rhodes Ryan E
Published: July 2022

Background

Research indicates that perceived behavioral control (PBC) is an important determinant of behavior and that it is composed of perceived capability and opportunity. However, typical measurement of these constructs may be confounded with motivation and outcome expectations. Vignettes presented before questionnaire items may clarify construct meaning leading to precise measurement.

Purpose

The purpose of this study was to develop and validate measures of perceived capability and opportunity that parse these constructs from the influence of motivation and outcome expectations using vignettes.

Methods

Study 1 collected feedback from experts (N = 9) about the initial measure. Study 2a explored internal consistency reliability and construct and discriminant validity of the revised measure using two independent samples (N = 683 and N = 727). Finally, using a prospective design, Study 2b (N = 1,410) investigated test–retest reliability, construct and discriminant validity at Time 2, and nomological validity.

Results

After Study 1, the revised measure was tested in Studies 2a and 2b. Overall, the evidence suggests that the measure is optimal with four items for perceived capability and three for the perceived opportunity. The measure demonstrated strong internal consistency ( > 0.90) and test–retest reliability (intraclass correlation coefficients [ICCs] > .78). The measure also showed construct and discriminant validity by differentiating itself from behavioral intentions (i.e., motivation) and affective attitude (based on expected outcomes) (SRMR = 0.03; RMSEA = 0.06). It also demonstrated evidence of nomological validity as behavior 2 weeks later was predicted.

Conclusions

We recommend researchers use this tool in future correlational and intervention studies to parse motivation and outcome expectations from perceived capability and opportunity measurement.
The Milan System for Reporting Salivary Gland Cytopathology
Authors: Hindi Issa , Simsir Aylin , Szeto Oliver , Hernandez Osvaldo , Sun Wei , Zhou Fang , Brandler Tamar C
Published: July 2022

Objectives

Our study assesses whether the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) offers any benefit over the original cytology classification, and measures interobserver agreement.

Methods

Four cytopathologists retrospectively blindly classified preoperative cytology by MSRSGC from 101 resected salivary tumors. Consensus MSRSGC diagnoses were correlated with surgical pathology diagnoses and compared with the original cytology classification. Diagnostic parameters were calculated for both systems. Interobserver variability was assessed.

Results

The original cytology classification vs MSRSGC had sensitivity, specificity, positive predictive value, and negative predictive value of 75.0% vs 78.3%, 97.1% vs 98.0%, 91.2% vs 94.7%, and 90.1% vs 90.0%, respectively. The original cytology classification risk of neoplasm (RON) was 91.7% for “negative for malignancy” and 100.0% for other categories. The MSRSGC RON was 71.4% in category II (nonneoplastic) and 100.0% in all other categories. The original cytology classification risk of malignancy (ROM) ranged from 0.0% for “atypical” to 100.0% for “positive for malignancy.” The MSRSGC ROM ranged from 0.0% in categories I (nondiagnostic) and III (nonneoplastic) to 100.0% in category VI (malignant). Weighted agreement using the MSRSGC was 92% (Gwet AC1, 0.84); unweighted agreement was 69% (Gwet AC1, 0.64). MSRSGC category IVA (benign neoplasm) was most likely to show interobserver agreement, with complete agreement in 67% of cases.

Conclusions

The MSRSGC performs similarly to the original cytology classification and shows relatively high interobserver agreement.
Leaf trait covariation and controls on leaf mass per area (LMA) following cotton domestication
Authors: Lei Zhangying , Westerband Andrea C , Wright Ian J , He Yang , Zhang Wangfeng , Cai Xiaoyan , Zhou Zhongli , Liu Fang , Zhang Yali
Published: July 2022

Background and Aims

The process of domestication has driven dramatic shifts in plant functional traits, including leaf mass per area (LMA). It remains unclear whether domestication has produced concerted shifts in the lower-level anatomical traits that underpin LMA and how these traits in turn affect photosynthesis.

Methods

In this study we investigated controls of LMA and leaf gas exchange by leaf anatomical properties at the cellular, tissue and whole-leaf levels, comparing 26 wild and 31 domesticated genotypes of cotton (Gossypium).

Key Results

As expected, domesticated plants expressed lower LMA, higher photosynthesis and higher stomatal conductance, suggesting a shift towards the ‘faster’ end of the leaf economics spectrum. At whole-leaf level, variation in LMA was predominantly determined by leaf density (LD) both in wild and domesticated genotypes. At tissue level, higher leaf volume per area (Vleaf) in domesticated genotypes was driven by a simultaneous increase in the volume of epidermal, mesophyll and vascular bundle tissue and airspace, while lower LD resulted from a lower volume of palisade tissue and vascular bundles (which are of high density), paired with a greater volume of epidermis and airspace, which are of low density. The volume of spongy mesophyll exerted direct control on photosynthesis in domesticated genotypes but only indirect control in wild genotypes. At cellular level, a shift to larger but less numerous cells with thinner cell walls underpinned a lower proportion of cell wall mass, and thus a reduction in LD.

Conclusions

Taken together, cotton domestication has triggered synergistic shifts in the underlying determinants of LMA but also photosynthesis, at cell, tissue and whole-leaf levels, resulting in a marked shift in plant ecological strategy.
Patch quality and habitat fragmentation shape the foraging patterns of a specialist folivore
Authors: Crowther Mathew S , Rus Adrian I , Mella Valentina S A , Krockenberger Mark B , Lindsay Jasmine , Moore Ben D , McArthur Clare
Published: July 2022

Research on use of foraging patches has focused on why herbivores visit or quit patches, yet little is known about visits to patches over time. Food quality, as reflected by higher nutritional quality and lower plant defenses, and physical patch characteristics, which offer protection from predators and weather, affect patch use and hence should influence their revisitation. Due to the potentially high costs of moving between patches, fragmented habitats are predicted to complicate foraging decisions of many animals. We aimed to determine how food quality, shelter availability and habitat fragmentation influence tree reuse by a specialist folivore, the koala, in a fragmented agricultural landscape. We GPS-tracked 23 koalas in northern New South Wales, Australia and collated number of revisits, average residence time, and average time-to-return to each tree. We measured tree characteristics including food quality (foliar nitrogen and toxic formylated phloroglucinol compounds, FPCs concentrations), tree size, and tree connectedness. We also modeled the costs of locomotion between trees. Koalas re-visited isolated trees with high leaf nitrogen disproportionately often. They spent longer time in trees with high leaf nitrogen, and in large trees used for shelter. They took longer to return to trees with low leaf nitrogen. Tree connectivity reduced travel costs between patches, being either individual or groups of trees. FPC levels had no detectable effect on patch revisitation. We conclude that food quality and shelter drive koala tree re-visits. Scattered, isolated trees with nutrient-rich leaves are valuable resource patches for koalas despite movement costs to reach them.
Alzheimer’s disease, cerebrovascular disease and dementia: lump, split or integrate?
Authors: Biessels Geert Jan
Published: July 2022

This scientific commentary refers to ‘Cerebral amyloid angiopathy interacts with neuritic amyloid plaques to promote tau and cognitive decline’ by Rabin et al. (https://doi.org/10.1093/brain/awac178).