bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding feasibility and vibrational characteristics of single-strand spacer-added DNA and protein complexes
Authors: Bashar Saima , Jo Soojin , Tandon Anshula , Lee Byung Ho , Dugasani Sreekantha Reddy , Kim Moon Ki , Park Sung Ha
Published: May 2022

Two of the most important features in the field of nanotechnology are self-assembly with nanometre-scale precision, and the self-alignment of functionalised nanomaterials. Here, we discuss the binding feasibility of single-strand spacer-added DNA building blocks to biotin–streptavidin (SA) complexes. We use atomic force microscopy, photoluminescence (PL) spectroscopy, and dynamic simulation to study the topological, optical, and vibrational characteristics of DNA lattices. To construct the DNA lattices, we use two distinct DNA building blocks, i.e. a double-crossover tile with a biotin (DXB), and a double-crossover tile with a flexible single-strand spacer containing a biotin (DXSB). Biotinylated DXB and DXSB lattices grown on the substrate eventually attracted streptavidins (SA, a tetramer protein) and formed DXB + SA, and DXSB + SA lattices, respectively. Furthermore, we examine the feasibility of alignments of an individual DXB (DXSB) tile on SA-bound DXB (DXSB) lattices, and a SA-conjugated Au nanoparticle (NP) on DXB (DXSB) lattices. To use more than two binding sites of biotins on SA (to serve as a connector between biotinylated tiles), the introduction of flexible single-strand spacers in DX tiles helped to overcome geometrical hindrance. In addition, the PL spectra of DXB and DXSB lattices with SA–Au conjugates are analysed to understand the periodic bindings of Au NPs on DXB (DXSB) lattices. We also conduct dynamic simulations of modal analysis and molecular dynamics simulation, which provide the vibrational characteristics and evidence of the importance of single-strand spacer-added DNA samples. Patterning of nanomaterials with specific functionalities with high precision using a simple method would be useful for the manufacture of high-density nanoelectronic devices and extreme-sensitivity biosensors.
Bayesian evaluation of residual production cross sections in proton-induced nuclear spallation reactions
Authors: Peng Dan , Wei Hui-Ling , Chen Xi-Xi , Wei Xiao-Bao , Wang Yu-Ting , Pu Jie , Cheng Kai-Xuan , Ma Chun-Wang
Published: May 2022

Residual production cross sections in spallation reactions are key data for nuclear physics and related applications. Spallation reactions are very complex due to the wide range of incident energies and abundant fragments involved. Therefore, it is challenging to obtain accurate and complete energy-dependent residual cross sections. With the guidance of a simplified EPAX formula (sEPAX), the Bayesian neural network (BNN) technique is applied to form a new machine learning model (BNN + sEPAX) for predicting fragment cross sections in proton-induced nuclear spallation reactions. Three types of sample dataset for measured residual production cross sections in proton-induced nuclear spallation reactions are made, i.e. D1 consists of isotopic cross sections in reactions below 1 GeV/u, D2 consists of fragments excitation functions of reactions up to 2.6 GeV/u, and D3 is a hybrid of D1 and D2. With the constructed BNN and BNN + sEPAX models, the isotopic and mass cross section distributions are compared for the 356 MeV/u 40Ca + p and 1 GeV/u 136Xe + p reactions, and fragment excitation functions in 40Ca + p, 56Fe + p, 138Ba + p and 197Au + p reactions. It is found that the BNN model needs sufficient information to achieve good extrapolations, while the BNN + sEPAX model performs better extrapolations based on less information due to the physical guidance of the sEPAX formulas. It is suggested that the BNN + sEPAX model provides a new approach to predict the energy-dependent residual production cross sections produced in proton-induced nuclear spallation reactions of incident energies from tens of MeV/u up to several GeV/u.
Impurity screening and Friedel oscillations in Floquet-driven two-dimensional metals
Authors: Asmar Mahmoud M , Tse Wang-Kong
Published: May 2022

We develop a theory for the non-equilibrium screening of a charged impurity in a two-dimensional electron system under a strong time-periodic drive. Our analysis of the time-averaged polarization function and dielectric function reveals that Floquet driving modifies the screened impurity potential in two main regimes. In the weak drive regime, the time-averaged screened potential exhibits unconventional Friedel oscillations with multiple spatial periods contributed by a principal period modulated by higher-order periods, which are due to the emergence of additional Kohn anomalies in the polarization function. In the strong drive regime, the time-averaged impurity potential becomes almost unscreened and does not exhibit Friedel oscillations. This tunable Friedel oscillations is a result of the dynamic gating effect of the time-dependent driving field on the two-dimensional electron system.
Metadynamics molecular dynamics and isothermal Brownian-type molecular dynamics simulations for the chiral cluster Au18
Authors: Lim C C , Lai S K
Published: May 2022

In an effort to gain insight into enantiomeric transitions, their transition mechanism, time span of transitions and distribution of time spans etc, we performed molecular dynamics (MD) simulations on chiral clusters Au10, Au15 and Au18, and found that viable reaction coordinates can be deduced from simulation data for enlightening the enantiomeric dynamics for Au10 and Au15, but not so for Au18. The failure in translating the Au18-L ⇌ Au18-R transitions by MD simulations has been chalked up to the thermal energy k
B
T at 300 K being much lower than energy barriers separating the enantiomers of Au18. Two simulation strategies were taken to resolve this simulation impediment. The first one uses the well-tempered metadynamics MD (MMD) simulation, and the second one adeptly applies first a somewhat crude MMD simulation to locate a highly symmetrical isomer Au18S and subsequently employed it as initial configuration in the MD simulation. In both strategies, we work in collective variable space of lower dimensionality. The well-tempered MMD simulation tactic was carried out aiming to offer a direct verification of Au18 enantiomers, while the tactic to conduct MMD/MD simulations in two consecutive simulation steps was intended to provide an indirect evidence of the existence of enantiomers of Au18 given that energy barriers separating them are much higher than ca. k
B
T at 300 K. This second tactic, in addition to confirming indirectly Au18-L and Au18-R starting from the symmetrical cluster Au18S, the simulation results shed light also on the mechanism akin to associative/nonassociative reaction transitions.
Metal nanoparticle arrays via a water-based lift-off scheme using a block copolymer template
Authors: Landeke-Wilsmark Björn , Hägglund Carl
Published: May 2022

Metal nanoparticles (NPs) can exhibit unique electronic, magnetic, optical, and catalytic properties. Highly ordered, dense arrays of non-close-packed, surface-supported metal NPs are thus of potential use in a wide range of applications. Implementing such arrays over large surfaces can, however, be both technologically challenging and prohibitively expensive using conventional top-down nanofabrication techniques. Moreover, many existing patterning methods are too harsh for sensitive substrate surfaces and their applications. To address this, we here investigate a fabrication protocol involving a water-based lift-off scheme in which the template pattern generation is rapidly and inexpensively achieved through block copolymer (BCP) self-assembly. A three-layer lift-off stack consisting of, from top to bottom, a poly(styrene-block-2-vinyl pyridine) template, a SiO
x
intermediate hardmask, and a water-soluble poly(vinyl alcohol) sacrificial layer is employed in this endeavor. Solvent-induced surface reconstruction (SISR) is used to generate an initial surface topography in the BCP template which is subsequently transferred to the layers beneath in a sequence of reactive ion etching steps. Through judicious selection of stack materials and dry etch chemistries, a layered, high-aspect-ratio, nanoporous mask is thus implemented. After metal deposition, the mask and excess material are simply removed in a lift-off step by dissolving the bottommost sacrificial layer in water. The incorporation of an intermediate hardmask and a water-soluble sacrificial layer obviates the need for harmful and/or corrosive lift-off solvents and decouples the BCP self-assembly process from the influence of substrate properties. We demonstrate the generation of well-ordered arrays of Au NPs capable of supporting sharp, localized surface plasmon resonances. We also investigate improvements to large-scale uniformity, as this is found sensitive to the SISR termination step in the original protocol. Extensions of the technique to other BCP morphologies and materials deposited ought to be straightforward.
Chemical imaging of oxide confinement layers in

GaAs/AlxGa1−xAs

VCSELs
Authors: Mokhtari Merwan , Pagnod-Rossiaux Philippe , Levallois Christophe , Pofelski Alexandre , Laruelle François , Botton Gianluigi A , Landesman Jean-Pierre
Published: May 2022

The authors have studied the lateral oxidation of

Al

x

Ga

1
−
x

As

layers buried in vertical-cavity surface-emitting lasers using cross-sectional scanning transmission electron microscopy coupled with electron energy loss spectroscopy. Chemical maps and composition profiles of the oxidized AlO
x
layers have been produced. The sensitivity is such that trace compositions of a few % As and Ga can be detected in the AlO
x
with a spatial resolution of a few nanometers on the recorded chemical maps. To demonstrate the performance of the mapping technique, we compare results from an area in the vertical-cavity surface-emitting laser (VCSEL) which is pure

Al

x

Ga

1
−
x

As

to an oxidized area. These measurements are performed on a thin sample prepared by the focused ion beam technique within an actual VCSEL, which makes the mapping technique applicable for degradation investigations in devices at different stages of their lifetime. More generally, this measurement method is effective for detailed evaluation of AlO
x
layers and their fabrication process.
Improvement of thermal resistance in InGaAs/GaAs/AlGaAs microdisk lasers bonded onto silicon
Authors: Zubov F I , Moiseev E I , Nadtochiy A M , Fominykh N A , Ivanov K A , Makhov I S , Dragunova A S , Maximov M V , Vorobyev A A , Mozharov A M , Mintairov S A , Kalyuzhnyy N A , Gordeev N Yu , Kryzhanovskaya N V , Zhukov A E
Published: May 2022

Epi-side down bonding on a silicon substrate of AlGaAs/GaAs microdisk lasers is presented. A heterostructure with coupled large optical cavities enables location of an InGaAs quantum dot active region at a distance of ∼1 µm from the heterostructure surface. The thermal resistance was reduced to 0.2 and 0.1 K mW−1 for disks of 30 and 50 µm in diameter, respectively. The maximum continuous-wave power limited by the thermal rollover is more than doubled after bonding.
A novel multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array
Authors: Peng Yun-Hao , Wang Dai-Hua
Published: May 2022

In order to only use one piezoelectric micropump to simultaneously drive and control multi-channel flow fluids of complex microfluidic systems in biological, chemical and medical applications, and then improve the integration and reduce the size of systems, principle and structure of a multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array are proposed and realized. The micropump is composed of one pumping unit and four active piezoelectric valves with annular boundaries, which form active piezoelectric valve array by uniformly distributing around pumping unit. All valves are connected to pumping unit by corresponding fluid channels and they can realize bidirectional fluid flowing. Therefore, pump can suck fluid from any one or more valves through pumping unit and can discharge fluid to the other one or more valves, which form its six working modes. Silicon-based pump body is processed by photoetching and the micropump is fabricated by fixing circular piezoelectric unimorph actuators on the silicon-based pump body. Flow rate model is established, the flow characteristics under each working mode are experimentally tested. Results show that the micropump can realize simultaneously multi-channel fluid input and output, when it works under three-in and single-out, it has the maximum flow rate and output pressure; the flow rate model can predict its flow rate, the maximum relative error between experimental test result and numerical simulation result is 9.99%; the micropump has high flow control accuracy, when amplitude of driving voltage varies from 35 V to 36 V with step of 0.1 V, it has the minimum change of flow rate of 1 μL min−1, the maximum flow rate deviation of 5 μL min−1 and the maximum relative standard deviation of flow rate control of 0.175%. Therefore, the micropump provide feasible scheme for piezoelectric micropumps to be applied in complex microfluidic systems with multi-channel flow fluids, such as lab-on-chip.
Anderson localization in the Anderson–Hubbard model with site-dependent interactions
Authors: Nguyen T H Y , Le D A , Hoang A T
Published: May 2022

We consider Anderson localization in the half-filled Anderson–Hubbard model in the presence of either random on-site interactions or spatially alternating interactions in the lattice. By using dynamical mean field theory with the equation of motion method as an impurity solver, we calculate the arithmetically and geometrically averaged local density of states and derive the equations determining the critical value for the phase transition between metallic, Anderson and Mott insulating phases. The nonmagnetic ground state phase diagrams are constructed numerically. We figure out that the presence of Coulomb disorder drives the system toward the Anderson localized phase that can occur even in the absence of Anderson structural disorder. For the spatially alternating interactions, we find that the metallic region is reduced and the Anderson insulator one is enlarged with increasing interaction modulation. Our obtained results are relevant to current research in ultracold atoms in disordered optical lattices where metal–insulator transition can be observed experimentally by using ultracold atom techniques.
Cosmological constraints on sub-horizon scales modified gravity theories with MGCLASS II
Authors: Sakr Z. , Martinelli M.
Published: May 2022

In this paper we introduce a new public Einstein-Boltzmann
solver, MGCLASS II, built as a modification of the publicly
available CLASS code, that allows to obtain cosmological
observables in Modified Gravity theories. It implements several
commonly used parameterizations of deviations from General
Relativity, computing their impact on the growth of structure as
well as on the background evolution of the Universe, together with a
subset of available alternative theories, still not completely ruled
out by observations. MGCLASS II is built in such a way to
be compatible with parameter estimation codes such as 
MontePython and Cobaya. We exploit this
possibility to constrain the parameterizations used by the Planck
collaboration, in order to validate the predictions of this new
code, and a newly implemented parameterization (z_flex) which has
different features. For the former we find good agreement with the
results existing in the literature, while we present original
constraints on the parameters of the latter, finding no significant
deviation from the standard cosmological model, ΛCDM.
Forward-backward asymmetries in

in the Bethe-Salpeter equation approach *
Authors: Liu Liang-Liang , Cui Su-Jun , Xu Jing , Guo Xin-Heng
Published: May 2022

Using the Bethe-Salpeter equation (BSE), we investigate the forward-backward asymmetries

in

in the quark-diquark model. This approach provides precise form factors that are different from those of quantum chromodynamics (QCD) sum rules. We calculate the rare decay form factors for

b and investigate the (integrated) forward-backward asymmetries in these decay channels. We observe the integrated

,

,

, and

; the hadron side asymmetries

; the lepton-hadron side asymmetries

; and the longitudinal polarization fractions

.
A Comparative Research of Thrust Simulation and Practice for the Small Solid Rocket Motor
Authors: Qin Xiaoyu , Shi Haoming , Wen Chunyu , Liu Shiyu
Published: May 2022

In practice, it is found that the simulation method applicable to the conventional size rocket motor cannot be directly applied to the design of the small rocket motor. Due to the change of size, the simulated thrust results differ greatly from the actual thrust results. In this paper, the tube grain and star grain are taken as examples to compare the simulated results with the actual experimental results. First, we determine a group of independent variables that can well reflect the changes of the main variables as a pretreatment and then use the zero dimensional interior ballistic algorithm for simulation. Finally, we design and conduct control experiments to draw a conclusion. The theoretical thrust was obtained by simulation and calculation, and the actual thrust was obtained by a lot of experiments. It was found that there were large offsets between the two types of grains, and the specific offsets corresponding to the two types of grains were obtained. The results show that there is a great difference between the simulated result and the actual result, which has a certain guiding significance for the design and research of small solid rocket motor.
Numerical simulations of sympathetic detonation of solid rocket motors
Authors: Pang Songlin , Chen Xiong , Xu Jinsheng
Published: May 2022

According to the numerical simulation, the sympathetic detonation of fiber composite shelled propellant was analyzed. Comparing the effects of fragments and reaction products shows that the impacting effect of fiber composite shell fragments is limited and can not lead the sympathetic detonation. The reason for sympathetic detonation in the closer distance is mainly reaction products.
Investigation into The Influences of Turbulence Models on Heating Prediction of Hypersonic Inflatable Aerodynamic Decelerator
Authors: Yang Hua , Ji Yi-min , Lin Jie , Chen Shu-sheng , Gao Zheng-hong
Published: May 2022

With the increasing demand for larger payloads for manned spaceflight and planetary exploration missions, hypersonic inflatable aerodynamic decelerator has gradually great application potentiality. The work presents the numerical simulations of hypersonic inflatable aerodynamic decelerator by the compressible Reynolds averaged Navier-Stokes equations with different turbulence models (such as SA, BSL, wilcox1988, SST). The pressure, eddy viscosity and heat flux under three Reynolds numbers (6.89E+6, 9.94E+6, 12.73E+6) are analyzed. The results demonstrate that the surface pressure distributions have slight difference, whereas the surface heating distributions appear remarkable diversity. In addition, compared with one equation turbulence model, two-equation turbulence models maybe more suitable for hypersonic heating predictions.
Iterative Guidance Algorithm for Lunar Soft Landing
Authors: Bojun Zhang , Zhanchao Liu
Published: May 2022

A closed-form explicit guidance algorithm for the deceleration, attitude adjustment and final landing phases before lunar probe soft landing is presented in this paper. Guidance with a variable-thrust engine is extended from the iterative guidance mode (IGM) to satisfy the terminal velocity, position, and attitude constraints. The closed form expression, obtained by integrating the acceleration and shutdown time, is analysed to obtain an explicit ex-pression for the velocity and position requirements and vertical touchdown of the spacecraft toward a designated landing site with high terminal accuracy. The influence of the attitude constraint on the motion equation is analysed to calculate the attitude, which is the physical control variable for the guidance loop. The variable thrust IGM formulation ensures the least switch of the thrust magnitude profile based on the analysis result of the residual flight altitude. The simulation results demonstrate that the proposed multi-constrained iterative guidance method can help accomplish an accurate lunar soft landing and that employed the algorithm is simple and easy to implement in engineering practice.
Continuous Integral Robust Roll Control for Single Moving- mass Controlled Reentry Vehicle
Authors: Zheng Jingzhong , Sergeevna Selezneva Maria
Published: May 2022

This paper concerns high-accuracy roll control for single moving-mass controlled reentry vehicle. Considering the simultaneous existence of matched and mismatched uncertainties in the reentry vehicle system, a continuous integral robust control strategy is proposed based on the backstepping design framework. The controller uses the error transformation method to transfer the mismatched modeling uncertainty to the control input channel, and then a robust structure constructed in the controller can handle it together with the matched modeling uncertainty. The final control input is continuously differentiable, which is benefit for tracking performance improvement and practical controller implementation. The proposed controller theoretically guarantees asymptotic tracking performance via Lyapunov analysis. Finally, simulation results are given to illustrate the efficiency of the proposed approach.
Influence of contact friction on static characteristics of multileaf bump foil bearing
Authors: Xu Ben , Zhang Jingyang
Published: May 2022

In order to reveal the influence mechanism of foil contact friction on the multi-leaf bump foil bearing performance, a deformation simulation model is established under the contact constraint of multi top foils and bump foils, and the analysis of the fluid-structure interaction is realized by combining with the Reynolds equation of compressible gas. The influence of the nonlinear variation of foil stiffness caused by contact friction on the static characteristics of the bearing under different bearing numbers is numerically analyzed. The results show: the foil stiffness increases nonlinearly with the foil deformation and presents the characteristic of circumferential non-uniformity. With the increase of the deformation of foil, the influence of friction coefficient on the foil stiffness is more significant. Within the parameters studied in this paper, the friction coefficient increases from 0 to 0.5, the bearing capacity increases first and then decreases when the bearing numbers is small; the bearing capacity increases monotonically when the bearing numbers is large, the higher the bearing numbers, the more significant the growth rate. The attitude angle increases with the increase of friction coefficient, and the bearing becomes more and more unstable. When the bearing numbers is large, we should pay more attention to the influence of friction on bearing performance. The computed model emphasizing nonlinear stiffness in this paper is close to the realities, and the results can provide guidance in the design of multi-leaf bump foil bearing.
Integrated Optimization of Aerodynamic and Electromagnetic Characteristics for Nozzle Central Cone
Authors: Zhang Saile , Yang Qingzhen , Wang Rui , Wang Xufei , Yang Haoqi
Published: May 2022

With the development and enhancement of anti-stealth technology and airborne radar, fighter jets will increasingly be threatened by the detection of airborne radar and ground-based radar. The exhaust system is a major radar scattering source in the backward direction of the aircraft due to its large open-ended property. A Radial-Based Function Neural Network Multi-Objective Particle Swarm Optimization (RBFNN-MOPSO) method is presented to reduce the nozzle’s radar cross section (RCS). Considering the geometric constraints and aerodynamic characteristics of the nozzle, 21 nozzle models with different types of cones are established by using uniform design (UD). The electromagnetic scattering characteristics of all the nozzles are simulated by Forward-Backward Iterative Physical Optics (FBIPO) method, and the Computational Fluid Dynamics (CFD) simulations have been conducted to obtain the flow field in the nozzle. After comprehensive evaluation and design by RBFNN-MOPSO, the mean value of RCS and thrust coefficient of the model have achieved good results. The process of optimization and design is proved to be effective and efficient for nozzle aerodynamic/electromagnetic integrated stealth design.
Primary research on influence of workpiece cooling on efficiency of Inconel’s 625 alloy elecrodischarge milling in carbon dioxide
Authors: Żyra A , Skoczypiec S
Published: May 2022

Inconel alloys one of the most cost intensive materials to machine with conventional machining methods. It is connected with its mechanical properties, as well as low thermal conductivity and also high material losses during machining. An alternative to conventional machining is electrodischarge machining (EDM), which enables to machine all the materials which are conductors or semi-conductors regardless its chemical composition and mechanical properties. There are three main dielectric types which can be used for EDM machining. The eco-friendly are gaseous ones. It is still hard to use gaseous dielectrics in the industrial applications, however it seems that this dielectrics are the future. The main aim of this research was to determine an influence of EDM milling in carbon dioxide used as dielectric in two configurations – with and without external workpiece cooling with deionized water on the EDM technological parameters (material removal rate, electrode wear) as well as technological surface integrity and surface structure.
Numerical Simulation of Dynamic Process of Variable Flow Gas Generator
Authors: Wei Yansong , Chen Xiong , Feng Wen , Liu Jingyi , Qi Shengju , Yang Guoce
Published: May 2022

In this paper, the research on the flow-adjustable gas generator of the solid rocket ramjet engine is carried out, and the internal flow field of the gas generator during the actuation of the flow control valve is analyzed. The steady and unsteady constant value simulations of the gas generator's working process are carried out respectively, and the static and dynamic flow field distributions in the control valve of the solid jet engine are obtained. The negative regulation in the gas flow adjustment process of the solid-jet engine is reproduced, and the reason for this phenomenon is analyzed based on the simulation results.
Framework Design and Key Technologies of Intelligent Management and Control Platform for Altitude Simulation Test Facility
Authors: Qiao Yanping , Zhao Wanli , Li Kai , Zhang Cong , Guo Yingqing
Published: May 2022

In this paper, based on the technologies such as intelligent operation and maintenance, data mining, etc., a design framework for the intelligent management and control platform of aero-engine altitude simulation test facility was proposed. Aiming at the problems of low data utilization rate of aero-engine altitude simulation test facility and insufficient level of intelligent control of the test process, with the current advanced experience in large-scale equipment management and control, an intelligent management and control platform for altitude simulation test facility can be constructed to effectively ensure the safety of test equipment. Improve test efficiency. The key technologies such as baseline modelling and database construction involved in the platform are summarized in order to realize the intelligent management of altitude simulation test facility, test data, software resources and the coordinated operation of test equipment, and promote the intelligent development of aero-engine altitude simulation test.
A simulation study of fracture toughness for a solid rocket motor contains a cracked propellant grain: Consideration of gas impingement effect
Authors: Wang Tingyu , Xu Jinsheng , Chen Xiong
Published: May 2022

It is essential to understand the fracture characteristics of a cracked propellant grain in a solid rocket motor during the motor ignition. In this paper, a finite element model of a solid rocket motor is developed, including the gas impingement flow field and the structural field. A circumferential crack is prefabricated on a round-hole type propellant grain. The gas pressure inside the cracked grain is obtained as a function of time by calculating the flow field. Then applying this pressure to the structural field, and J-integral at the crack tip can be calculated. The J-integral can represent the fracture toughness of the propellant. The results show that the circumferential crack in the propellant grain opens up as the gas pressure gradually increases. The J-integral values at the crack tip show an oscillating trend and are not monotonically increasing. This paper predicts the moment of crack propagation in the rocket motor grain under gas impingement conditions by comparing the JIC of the propellant.
Research on the statistical damage constitutive model for composite solid propellant
Authors: Li Hui , Song Qi-xuan , Wu Xuan , Xu Jin-sheng , Chen Xiong
Published: May 2022

The study of constitutive model of composite solid propellant is an important basis for analyzing the structural integrity of propellant grains of the solid rocket motor. From the view of microscopic, composite solid propellant is composed of a large number of solid particles with various sizes embedded in the matrix. In this paper, based on the distribution of solid particles with different sizes and the failure strength of the particle-matrix interfaces, the damage evolution was assumed to obey the Weibull distribution function and power law distribution function, and the two statistical damage constitutive models were first established. Then, the model parameters were identified and validated through the uniaxial tensile tests data of HTPB propellant. Finally, the prediction abilities of the developed two models were compared. The results show that both of the two statistical damage models can describe the stress-strain curves of HTPB propellant well.
Research on static characteristics of elastic foil gas thrust bearing applied to aeronautical ACM
Authors: Song Chao , Bian Zhi , Du Jianjun , Ding Shunan , Zhu Jianjun
Published: May 2022

In air conditioning system for aircraft, air cycle machine (ACM) is the flimsy core component, which is impacted observably by the performance and reliability of elastic foil air-dynamic pressure bearing. It's necessary to have research on static characteristics of elastic foil air-dynamic pressure bearing. Based on finite element analysis (FEA) theory, it’s clearly obtained that discretized fluid lubrication Reynolds equation of foil dynamic pressure bearing by the weighted residual method. Coupled with the elastic deformation of foil calculated by beam element model, foil gas film thickness equation is used to work out static characteristics of elastic foil air-dynamic pressure bearing by iterative calculation. And then, it’s known how the basic parameters of the bearing impact its static characteristics. The result of the method in this paper, is verified that it’s correct by the experiment data in other relevant papers, and it’s appropriate to be used as guidance and reference for the further application of elastic foil bearing in ACM.
Research on the Control System of Lathe Open-type Hydrostatic Slide
Authors: Zhang Zhendong , Wang Shengnan , Peng Shanshan
Published: May 2022

In order to make oil film thickness for lathe open-type hydrostatic slide stabilize and without changing following cutting forces, the lathe open-type hydrostatic slide was regarded as the research object. The equations of the control system of the oil film thickness for lathe open-type hydrostatic slide were established, which included the flow equations of slides and the force equations of dynamic slides. The control model of the control system of oil film thickness for lathe open-type hydrostatic slide was established. The parameters of the control model were determined through the identification and optimization, and its state space representation was derived. The PID control of the system was developed. The performance of the control system of oil film thickness had been significantly improved after the PID control. The static and dynamic performance of the system has further improved by conducting pole optimization allocation.
Simulation Analysis of Fault-tolerant Control for Dual Three- Phase Permanent Magnet Synchronous Motor
Authors: Xu Jing , Cui Yebing , Song Bing , Chen Tong , Wang Kai
Published: May 2022

According to the demand of aerospace electromechanical servo system, a new type of fault-tolerant dual three-phase permanent magnet motor(PMSM) and its control system with simple structure, high reliability and high power density are proposed. The dual three-phase PMSM's structure and control model are introduced, the fault-tolerant control algorithm for dual three-phase PMSM is proposed, the simulation model is built and the fault-tolerant control simulation analysis is carried out, Based on the dSPACE control platform, the performance of the synchronous motor prototype is tested, the motor test results show the feasibility of the dual three-phase PMSM and its fault-tolerant control algorithm, which establishes the engineering foundation for the further study of high-reliability electromechanical servo systems.
Study on the Heat Transfer and Ablation Characteristics of the Dual-Pulse Motor during the Working Process of the Barrier
Authors: Renjie SHEN , Yingkun LI , Xiong CHEN
Published: May 2022

In this paper, aiming at the problem of heat transfer and ablation prediction of phenolic resin/nitrile rubber in the insulation material in double pulse motor, based on pyrolysis kinetics and thermochemical ablation theory, a variable heat physical property model of nitrile rubber insulation material with temperature and time was established. A simulation study on the thermal diffusion and pyrolysis ablation of the barrier insulation materials was carried out. The ablation thickness and ablation rate of the barrier insulation material were obtained. The results show that the proposed ablation calculation model has a certain reference value for the ablation research of thermal insulation materials.
Follow me droney! Will UWB technology do it right?
Authors: Hanzel Krzysztof
Published: May 2022

Object tracking for consumer drones is currently a rapidly developing technology. Its implementation is currently carried out with the use of object-in-image detection, which often limits the latest possibilities of this technology. The disadvantage of such a solution is also the increase in energy demand and the need to provide additional computing power, or delays resulting from the transfer of this operation to the control device. The proposed solution to this problem in this article is the use of UWB (Ultra-wideband) technology, which is increasingly appearing in consumer devices. The possible yield related to the accuracy of determining the position of the object as well as the experimentally determined frequency of receiving information about the position was presented. Additional advantages, such as resistance to NLOS (non-line of sight) conditions, were also presented.
Rocker-Bogie Stair Climbing Robot
Authors: Choudhari Anagha , Deshpande Abhay , Tirgure Mayur , Parihar Chiya , Jibhakate Mrunal
Published: May 2022

Robotic technology is now applied in a variety of domains, including hazardous and urban situations, security, planetary systems, rescue missions, and military operations. The current mobility designs are difficult due to the amount of wheels or legs used. They are not designed to withstand the harsh environment of Mars in terms of mechanical breakdown. Four-Wheel rovers can navigate tough terrain thanks to an effective high degree of mobility suspension system. The rocker-bogie design’s most important mechanical feature is its drive train simplicity, which is achieved by having only two motors for motion. Six wheels are used since there are rarely obstacles on natural terrain that require both front wheels of the rover to climb at the same time.
Face Recognition using Nearest Neighbour and Nearest Mean Classification Framework : Empirical Analysis, Conclusions and Future Directions
Authors: Shanmuganathan M. , Nalini T.
Published: May 2022

Human Face recognition algorithms have made huge progress in the last decade. In this manuscript, we have presented an approach for the implementation of a face recognition system in a successful manner by varying pose, scale, lighting, and age variation. The different empirical analysis was performed with various datasets for face detection and face identification. Face identification system detects efficiently segments and recognizes face in a cluttered sequence under varying pose, lighting and age variations. From this experimental analysis morphological model outperformed k-NNC, NMC based closest mean classifier and informative knowledge distillation with fairly reasonable accuracy. Three proposed methods on the basis of an efficient way of handling the face recognition problems. The morphological method outperformed well when compared with k-NNC, NMC based closest mean classifier a proposed method, and another innovative method named Informative knowledge Distillation. The morphological method is suitable for large datasets where occlusion, pose variation, age variations, and different expression of images.
Design of A Low-Cost System for The Monitoring and Control of Public Lighting
Authors: Auccahuasi Wilver , Herrera Lucas , Rojas Karin , Echevarría Martha Romero , Grados Juan , Villavicencio Sergio , Illesca Omar , Calcina Edilberto , Meza Jessica , Cuzcano Abilio , Aviles Martha , Soria Alejandro Paredes , Salazar José Luis Herrera
Published: May 2022

The public lighting poles are part of the public lighting system, so its operation is important and is offered as a welfare mechanism for citizens, it has the disadvantage of the high cost of operation because it is in operation all night for 365 days of the year, in this work a low-cost system is designed to be able to supply power to the public lighting poles, based on a solar panel system and with sensors to be able to measure luminosity, voltages and current, this system sends the information to a base station using the XBEE protocol and viewed using LABVIEW software.
Developing a basis for heavy metal in-situ detection using CZT
Authors: Foley A. , Mohanty S.K. , Sjoden G.E.
Published: May 2022

Heavy metal contamination is a global concern–this type of
contamination in the environment has been on the rise since the
industrial age. Current guidelines from the United States
Environmental Protection Agency and the World Health Organization
limit arsenic concentration in water sources to
10 μg/kg. Typically, detection of heavy metals in industrial
processes include spectrophotometry and colorimetry. A viable
alternative for heavy metal detection can be implemented using a
room temperature gamma spectrometer paired with a portable neutron
generator for in-situ neutron activation analysis. In this paper, we
explore detection of an arsenic salt diluted in a water sample to
specific concentrations; the arsenic sample is utilized to determine
the capability of a 5 mm × 5 mm × 5 mm
CZT detector for heavy metal detection by neutron activation
analysis. Several arsenic dilutions were irradiated in the
University of Utah TRIGA reactor (UUTR), and the samples were
measured on both HPGe and CZT detectors. The direct comparator
method was used to determine the sample mass in a sample
attributed by each detector, and the results were compared to the
known dilution arsenic mass. We determined that a CZT gamma
spectrometer can reliably detect 10 mg/kg arsenic with high
confidence, and as low as 1 mg/kg arsenic with low confidence. For
comparison, an HPGe gamma spectrometer can reliably detect 1 mg/kg
arsenic with high confidence, and as low as 0.1 mg/kg with low
confidence. Based upon our MDA, the CZT spectrometer can detect
samples with a total activity of 1.8×10-5 mCi and higher,
and the HPGe detector can detect an activity of 1.8×10-6 
mCi. These results suggest the method has potential in portable
gamma spectrometry solutions for wastewater effluents from
industrial processes such as paint manufacturing, pharmaceutical,
and smelting operations.
Sustainability Assessment of Mosque: A Case Study of Design Proposal in Bandar Bertam Jaya, Penang
Authors: Asyraf Mohd Rodzi Khairul , Zelman Mohamoud Mohamad , Amalina Hanapi Nur
Published: May 2022

Mosque is a significant building typology for Muslims. Careful consideration on location and capacity should be practiced to increasing accessibility and promote comfort to worshippers. Due to high-density residential development, location of the nearest mosque and sense of unity among Muslims in the area, a local community was proposing a new mosque in Bandar Bertam Jaya, Penang to Majlis Agama Islam Negeri Pulau Pinang. A self-sustained mosque with phased development was proposed by Arkitek ICB Sdn. Bhd. With VELUX Daylighting Simulation and basic ventilation principle, the aim of the research is to study the sustainability of the design comprising daylighting and ventilation aspects respectively and how the proposal can give an impact to energy and resource management. The findings including Average Daylight Factor (ADF), opening sizes, wind speed and direction will also be reflected to Malaysian Standard MS 1525 and MS 2680 to value the sustainability aspect performed by the mosque. The findings of the research can be a reference to the architecture firm and the local community on the performance and sustainability of the proposal.
Acceptance on Building Information Modelling (BIM) Training in Selangor Construction Industry: Current Trend and Impediments
Authors: Ang P S E , Wong N Z , Kasim N , Osman M H , Adnan S H , Natasha N S , Ali R
Published: May 2022

Building Information Modelling (BIM) is known as one of the innovations of Information Technology (IT), globally used as a platform to promote collaborative and integrated working environments in the construction project management. The study’s major goals are to determine the existing BIM training trend and to identify impediments to BIM training acceptability in Malaysia’s Selangor construction industry. Out of 90 surveys submitted to G5 to G7 contractors, 60 completed the questionnaire completely, representing a response rate of 67 %. To acquire frequency, percentage, and mean value, the data were analysed using the statistical programme for social science (SPSS) version 26 and Microsoft Excel. These statistics from the current BIM training trend demonstrate that just a small percentage of businesses are using BIM. The majority of the. The majority of businesses lack clear BIM training initiatives. The expensive cost of software and upgrades, deploying processes and technology, and a lack of motivation and support from government and professional bodies are the most significant problems impeding BIM training uptake in the construction sector. This study supports the need for the government to provide more strategic provisions to secure the construction industry’s embrace of BIM training.
Building Information Modelling (BIM) in Malaysian Industrialised Building System (IBS) Construction Projects: Benefits and Challenges
Authors: Ang Soon Ern Peniel , Xian Yang Woo , Kasim Narimah , Hairi Osman Mohamad , Hani Adnan Suraya , Suhada Natasha Nor , Ali Roslinda
Published: May 2022

Building Information Modelling (BIM) is a digital depiction of a developed facility that provides an essential line of ‘integration’ in Industrialised Building System (IBS). BIM, according to the researchers, can help IBS building projects save money and improve budgeting and cost estimating. In the case of the IBS project, BIM has the ability to improve the design process. The building industry in Malaysia, on the other hand, is not progressing as predicted, contributing the least to economic productivity. In relation, BIM adoption would be a key factor of the breakthrough development of construction industry in term of the productivity and efficiency of the project delivery process. Thus, the objectives of this paper is to determine the benefits of using BIM in IBS construction and to identify the challenges of using BIM in IBS building in Malaysia. In Wilayah Persekutuan Kuala Lumpur, a questionnaire survey was given to 93 Grade 7 IBS contractors with BIM experience, 44 of them answered, resulting in a 47.3 percent response rate. Using SPSS software, the data was analysed using frequency analysis and the direct mean approach. According to the findings, the top five benefits of BIM implementation in the IBS industry are visualisation of design, improved cost estimating and budgeting, monitoring and controlling cash flow and cost, installation process, and initial work process, while the top five challenges of implementing BIM in the IBS construction industry in Malaysia are high costs for BIM training, BIM tools and experts, and lack of intellectual property protection. The outcome indicates that implementing BIM in IBS industry benefits the whole project delivery process from design to installation as well as cost performance. However, the financial and legal issues are the main challenges for BIM implementation in IBS industry. Thus, this study is significant in addressing both benefits and challenges of implementing BIM in IBS industry to the stakeholders and provide a perspective to catalyse the development of BIM and IBS construction industry.
An analysis of accidents involving public transport along highway
Authors: Shariff S S R , Nusa F N M , Hanizan H A , Taib M N
Published: May 2022

For years, Malaysia is known as one of the countries that has the highest figure of fatality accident. The staggering number of fatality accidents usually involved private transportation. There are a lot of studies that focus on the causes of the accidents and therefore, a lot of policies and law enforcement have been implemented in order to reduce fatality figure in private transportation. Unfortunately, studies in public transport are not at par with private transportation. Therefore, this study is aimed to analyse the accidents involving public transport specifically, buses along selected Malaysian highway. The analysis starts at describing the potential effects of physical factors namely locations and types of vehicles. Details statistical analysis on the effects of the two factors, locations and types of vehicles on the number of accidents are done. Results show that for the accidents that involve buses in 2018 and 2019, and locations of the accidents have significant association. Hence, this result should help bus drivers to be more alert when driving thru the identified locations.