bluuebunny/crossref_metadata_2025 huggingface dataset:
UV-Vis spectroscopic and colorimetric anion detection and fluorescence properties of new 3-amino-4-hydroxybenzenesulfonic acid-based Schiff bases depending on the strength and position of the electron donor substitution
Authors: Yildiz Elif Akhuseyin , Pepe Yasemin , Erdener Diğdem , Karatay Ahmet , Boyacioglu Bahadir , Ünver Hüseyin , Yapar Gönül , Demir Neslihan , Yıldız Mustafa , Elmali Ayhan
Published: July 2023

In this study, 3-amino-4-hydroxybenzenesulfonic acid-based imine compounds; 3-(2,5-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (1), 3-(2,4-dihydroxybenzylideneamino)-4-hydroxybenzenesulfonic acid (2) and 4-hydroxy-3-(2-hydroxy-3-methoxybenzylideneamino)-4-hydroxybenzenesulfonic acid (3) was synthesized. The compounds were analyzed using various spectroscopy methods, and the experimental UV–vis data matched the theoretical predictions. The compound1displayed lower stability, higher reactivity, and easier photoexcitation due to a smaller HOMO-LUMO energy gap. The investigated compounds1-3showed promise as chemosensors for anions, providing visible detection in daylight conditions. The compound3exhibited selective fluorescence at specific wavelengths. The compounds1-3interacted with DNA through electrostatic interactions. Also, compounds1-3showed higher antioxidant activity than BHT. However, fluorescence measurements indicated that the emission signals were strongly influenced by the position and strength of the electron-donating group. Adding a hydroxy or methoxy moiety near the -OH group on the phenyl ring decreased the fluorescence signal due to intersystem crossing and intramolecular charge transfer mechanisms, respectively. These findings were supported by femtosecond transient absorption spectroscopy measurements. The results emphasize the significance of substituents in imines derived from 3-amino-4-hydroxybenzenesulfonic acid in determining their biological activities, as well as their optical and sensor properties.
Melnikov chaos, control and synchronization of fractal Josephson junction
Authors: Osseni C O A , Miwadinou C H , Monwanou A V
Published: July 2023

Josephson junctions due to their memory and non-linearity properties have considerably impacted the exact sciences and technological fields in particular. In this study, we investigate the existence criteria of Smale’s horseshoe chaos in a fractal junction by considering the non-harmonic constant of the super current of the junction. After having analytically studied the conditions of existence of this chaos by means of Melnikov’s theorem and verifying its predictions by drawing the basins of attraction, we have analyzed the influence of certain control parameters on the dynamics of the system. The control and synchronization of the system have been carried out for its practical use in electronics in integrated circuits , for example, and in telecommunications for the storage of information and the securing of data. The motivation of this study is to bring out the possible and complete dynamics of a fractal junction by considering the non-harmonic constant of the super current of the junction in order to expand the old research work carried out and to promote a more detailed knowledge of the behaviors of this system.
Topological phase transitions and topological flat bands on the ruby lattice
Authors: Yang Yuan , Shu Chang-Rong , Li Xiao-Bing
Published: July 2023

We investigate the topological properties of a tight-binding model on the two-dimensional ruby lattice in the presence of staggered fluxes. The variation of the nearest- and next-nearest-neighbor hopping parameters yields tunable Chern-number bands, which may host quantum anomalous Hall insulators at different filling fractions. Interestingly, we obtain topological nontrivial bands with high Chern number C = −4. We show that topological phase transitions among different gapped phases are accompanied with the gap closing and reopening processes. Furthermore, we find topological flat bands with Chern number C=+1, which could be a platform for realizing a fractional quantum Hall effect.
Predictions of the ratio and asymmetry probes of the invisible Z-boson decay
Authors: Saygin Kadir
Published: July 2023

Higher-order predictions through the combined accuracy including next-to-leading order (NLO) electroweak (EW) and next-to-NLO (NNLO) quantum chromodynamics (QCD) corrections in underlying perturbation theories are presented thoroughly for the invisible decay of the Z boson into neutrino pair relative to its decay into charged-lepton pair (leptonic decay). The combined NNLO QCD+NLO EW predictions are achieved based on the fully-differential calculations of cross sections of both the invisible and leptonic processes in proton-proton (pp) collisions at 13 TeV center-of-mass energy. Differential distributions of cross-section ratios of the invisible process to the leptonic process are presented as a function of the transverse momentum of the Z boson

p

T

Z

. For the first time, the predictions for differential distributions of cross-section asymmetries between the invisible process and the leptonic process are presented in bins of the

p

T

Z

. The cross-section ratio and asymmetry distributions, which are referred to as the invisible probes, are considered to be important for controlling the invisible process by the leptonic process of the Z boson and probing deviation from the Standard Model (SM) for new-physics searches. The predictions are extensively presented beyond the Z-boson mass resonance region to assess the potential of the invisible ratio and asymmetry probes for new-phenomena searches in high-invariant mass region of the lepton-pair final states. Various tests with threshold requirements of transverse momenta of neutrino pair and leptons are performed to assess the impact on the combined predictions. The invisible ratio and asymmetry probes are proposed to be important probes for indirect searches of new-physics scenarios.
Re-examination of β-decay in Hg, Pb and Po Isotopes
Authors: Nabi Jameel-Un , Bayram Tuncay , Riaz Muhammad , Ullah Asim , Hayder Anes , Şenturk Şevki , Böyükata Mahmut
Published: July 2023

This study re-examines the effect of nuclear deformation on the calculated Gamow-Teller (GT) strength distributions of neutron-deficient (178−192Hg, 185−194Pb and 196−206Po) nuclei. The nuclear ground state properties and shape parameters were calculated using the Relativistic Mean Field model. Three different density-dependent interactions (D3C, DD-ME2 and DD-PC1) were used in the calculation. Estimated shape parameters were later used within the framework of deformed proton-neutron quasi-random phase approximations model, with a separable interaction, to calculate the GT strength distributions, half-lives and branching ratios for these neutron–deficient isotopes. It was concluded that half-lives and GT strength distributions vary considerably with change in shape parameter.
Convenient quantum controlled teleportation of two-qubit pure state with seven-qubit entangled state
Authors: Ma Yun
Published: July 2023

Based on a seven-qubit entangled state, Chen et al (2020 Int. J. Theor. Phys.
59 1402) presented a scheme for controlled quantum teleportation. Using the same quantum channel state, we put forward a new scheme in which the quantum information sender can also transmit a Bell state to receiver under the agreement and assist of the controller. The comparison with Chen et al’s scheme is made and reveals its distinct advantage of reducing the classical resource consumption and increasing the intrinsic efficiency as well as degrading the complexity of necessary operations.
Electromagnetic pulses with non-zero electric area in transition radiation
Authors: Rosanov N N
Published: July 2023

An analysis was made of the electric area—the time integral of the electric field strength—of pulses that occur during transition radiation when charged particles cross the interface between two media with different electromagnetic characteristics. Exact expressions are obtained for the longitudinal and transverse (radial) components of the electric area, which determines, in the case of extremely short pulses, the effectiveness of their impact on micro-objects.
Nonlinear current response and electric quantum oscillations in the Dirac semimetal Cd3As2
Authors: Cui Hao-Nan , Wu Ze-Nan , Wang Jian-Kun , Zhu Guang-Yu , Yang Jia-Jie , Zheng Wen-Zhuang , Liao Zhi-Min , Wang Shuo , Lin Ben-Chuan , Yu Dapeng
Published: July 2023

Chiral anomaly is a distinct quantum anomaly associated with chiral fermions in Dirac or Weyl semimetals. The use of negative magnetoresistance (negative MR) as a signature for this anomaly remains contentious, as trivial mechanisms such as current jetting and weak localization can also induce negative MR. In this study, we report a novel nonlinear behavior of the chiral anomaly in the longitudinal direction, which we observed by applying parallel current and magnetic field to the Dirac semimetal Cd3As2. This nonlinear characteristic peaks at an intermediate magnetic field of approximately 5 T, displaying a resistance-increasing property concomitant with strengthening of the current source. Through angle-dependence experiments, we were able to rule out trivial factors, such as thermal effects, geometric artifacts, and anisotropy. Furthermore, additional electric quantum oscillations were observed when the direct current (DC) was applied as high as 300 μA. Such an unusual phenomenon is ascribed to the formation of quantized levels due to Bloch oscillation in the high DC regime, suggesting that an oscillatory density distribution may arise as the electric field increases. The non-Ohmic electric quantum oscillations open a new avenue for exploring chiral anomaly and other nontrivial topological properties, which is also one of the salient features of nonequilibrium steady states in condensed matter physics.
Phase-stepping interferometry for parallelism measurement of step gauge faces
Authors: Sharma Sucheta , Nysten Johan , Lassila Antti , Ikonen Erkki
Published: July 2023

The article presents a measurement method driven with a non-contact optical system consisting of a mirror array by employing phase stepping interferometry to determine the surface parallelism of step gauge faces. The array houses a prism mirror to allow simultaneous interferometric measurement of two opposite step gauge faces relative to the front surface. Mechanical movement of the mirror array is detected using an alignment monitoring mirror to compensate the tilt angle of the system. The front surface of the step gauge and the alignment mirror, located at the measurement arm of the interferometer, are adjusted normal to the collimated laser beam of 50 mm diameter. Phase stepping is performed by a piezo controlled mirror at the reference arm. A theoretical approach is described to verify the experimentally obtained sensitivities of the system due to yaw and pitch misalignments of the mirror array and the step gauge. The technique offers improved measurement accuracy to measure the parallelism of the step gauge faces. Main uncertainty components are caused by the plane fitting analysis of non-ideal surfaces and repeatability of the results. The combined standard uncertainty of parallelism measurement is 18 µrad.
High-density magnetomyography is superior to high-density surface electromyography for motor unit decomposition: a simulation study
Authors: Klotz Thomas , Lehmann Lena , Negro Francesco , Röhrle Oliver
Published: July 2023

Objective. Studying motor units is essential for understanding motor control, the detection of neuromuscular disorders and the control of human–machine interfaces. Individual motor unit firings are currently identified in vivo by decomposing electromyographic (EMG) signals. Due to our body’s properties and anatomy, individual motor units can only be separated to a limited extent with surface EMG. Unlike electrical signals, magnetic fields do not interact with human tissues. This physical property and the emerging technology of quantum sensors make magnetomyography (MMG) a highly promising methodology. However, the full potential of MMG to study neuromuscular physiology has not yet been explored. Approach. In this work, we perform in silico trials that combine a biophysical model of EMG and MMG with state-of-the-art algorithms for the decomposition of motor units. This allows the prediction of an upper-bound for the motor unit decomposition accuracy. Main results. It is shown that non-invasive high-density MMG data is superior over comparable high-density surface EMG data for the robust identification of the discharge patterns of individual motor units. Decomposing MMG instead of EMG increased the number of identifiable motor units by 76%. Notably, MMG exhibits a less pronounced bias to detect superficial motor units. Significance. The presented simulations provide insights into methods to study the neuromuscular system non-invasively and in vivo that would not be easily feasible by other means. Hence, this study provides guidance for the development of novel biomedical technologies.
Research and development of copper joint for ITER In-Vessel Coils
Authors: Hao Qiangwang , Jin Jing , Wang Hua , Liu Xiaochuan , Tao Bowei , Wu Yu , Vostner Alexander , Laquiere Julien , Claudio Fichera
Published: July 2023

The ITER In-Vessel Coils (IVCs) are crucial components of the Tokamak fusion reactor. They are located within the vacuum vessel (VV) behind the blanket shield modules and are responsible for compensating for fast perturbations of the plasma. There are a total of 176 joints used to connect the IVCs, feeders and feedthrough. The joint structure consists of a central copper conductor, a mineral (MgO) insulation layer, and an outer stainless-steel jacket. Given the inaccessibility of the IVCs once the blanket modules are installed, the highest level of quality is required for the joints. One key item is the welding of the copper conductor which has to be done inside the VV. To address the high thermal conductivity of copper conductor and the challenging constraints working inside the VV, a preheating method by the arc of the welding head has been developed. Macro- and micro-structure examination were performed on the welding cross sections, and tensile tests were carried out to check the strength of the copper joint, which demonstrated that arc preheating does not have a significant impact on the heat-affected zone. After more than 40 welding attempts and several design updates, the copper joint has been successfully developed and can be repeatedly and successfully welded.
A model of sustainable information security management system in higher education institutions
Authors: Sikman Lj , Latinovic T , Sarajlic N , Sikanjic G
Published: July 2023

Modern business systems have the expectations and requirements of users and stakeholders for safer and better services that are constantly growing. The increasing use of information technology in business increases the threats and vulnerabilities to which information resources are exposed, which causes an increase in information risks. Many business institutions must constantly monitor their activities to establish an organized and sustainable information security management system and services. The requirements of the international standard ISO/IEC 27001 and the generally accepted COBIT management framework are important for the application of such a system. The paper presents a model of a sustainable information security management system (ISMS) at universities.
Computing the value of uneven raising of building consisting of nine segments deflected from vertical due to mining exploitation
Authors: Gromysz K , Orwat J
Published: July 2023

Deflection of buildings from vertical is a common damage caused by underground mining. Its removal consists in tearing the building apart at the level of one of the storeys, most often in the basement, and then unevenly lifting a part of the building above the tearing plane with the use of piston hydraulic jacks. One of the conditions for a properly carried out rectification is the correct computing of the height of lifting the individual corners of the building. The subject of the article is the deflected from vertical building of large projection (64.0 m × 41.9 m). The building consists of nine dilated segments, which are functionally related. The width of expansion joints between segments is about 10 cm. The deflection from vertical of the building occurred as a result of deformation of the mining area. Due to the significant projection of the building, the deflection of each segment is not the same. It was decided that deflection of the building would be removed by uneven raising of the structure with jacks mounted in the walls. The method of computing the value of uneven raising of the building is presented. In the first step the deflection of each segment was identified. Than the segments were divided into groups, due to their functional solutions. Then, for each group, the average deflection was determined. On the basis of this deflection, the values of uneven raising of each segment were determined. Described procedure made it possible to minimize the number of steps that will appear between the segments. Thanks to this, the building will regain functionality after carrying out the planned renovation.
Energy efficiency of the Process Planning Design in the scope of Industry 4.0
Authors: Borojević S , Sredanović B , Milošević M , Sekulić M , Janković S
Published: July 2023

In this paper we present an experimental investigation in the scope of Industry 4.0 that provide an answer to the question of whether and to what extent operation sequencing during machining affects the output parameters of process planning design: main production time (MPT) and total energy consumption (TEC). Main production time is the basic indicator of productivity, while total energy consumption is an indicator of energy efficiency of the process. After experimental research, a relation was established between the variants of operation sequencing during machning, on the one hand, and main production time and total energy consumption, on the other hand.
Pressure and flow control loop for serial and parallel hydraulic systems powered by the frequency converters
Authors: Klincov Z , Knezevic B Z , Erceg D , Grahovac Z
Published: July 2023

Frequency converters are electronic devices used in automated processes to control the speed of an electric motor. The aim of this paper is to prove that frequency converters can replace PLCs in smaller automated hydraulic systems. For the realization of this research, an experimental setup was used, which consists of two separate systems, and each system consists of: pump, frequency converter, command table, pressure and flow sensors. Using manual valves, it is possible to connect two systems into one, serial or parallel, in order to achieve higher value of pressure or flow, respectively. The first part of the paper describes the experimental setup as well as hydraulic and control scheme. After that, the used procedure of setting the parameters of the PI controllers was described. Programming and settings of parameters was performed for cases when the systems are connected in series and in parallel, and in both control cases only one control loop was used, which was implemented in only one frequency converter, while the second frequency converter was controlled by a loop signal from the first converter. The methods used to adjust the parameters of the PI controller proved to be correct and precise and reliable pressure and flow control was achieved for the cases of serial and parallel system, respectively. The pumps run at the same speeds and because of that they are able to achieve the same pressure or flow values in the system at any time. At the end, the measurement results were presented.
Design and optimization study of a resistance structure for an industrial storage platform supporting injection molding tools for the automotive industry
Authors: Alic D D , Pinca Bretotean C
Published: July 2023

The paper offers an optimized solution for an industrial storage platform supporting injection molding tools used to produce thermoplastic components in the automotive sector. After analyzing the current situation for storing the massive tools, a work platform was proposed in order to ensure the conditions imposed by the extension of the company’s implementation of LEAN methods to streamline the production flow. The design of the resistance structure was modeled in the program Autodesk Inventor Professional 2020, taking into account realistic loads and their statistical distribution in the construction of the static and loading scheme of the main beam. The analysis of stress and strain in the main beam under the action of external loads was performed using the finite element method of the program Autodesk Inventor Nastran. The optimized solution for the main beam has been found by analyzing the optimization possibilities in three steps: structural optimization, dimensional optimization and the validation of the proposed optimization options, by verifying the safety of the structure. This paper presents in detail the choice of optimization criteria, decision variables, constraints and objective function. Based on the numerical analysis of mechanical stress and safety coefficient in operation, an optimal variant was chosen from the analyzed models: recessed articulated structure simple and with intermediate support, using laminated profiles IPE 200 and IPE 140.
Investigation of dynamic behaviour of one complex steel structure
Authors: Golubovic-Bugarski V , Sredanović B , Milovanović S , Vukomanović R , Petković S , Todić M
Published: July 2023

This paper deals with dynamic analysis of a steel structure, constructed by steel beams and pillars which are connected by bolts. This structure is designed to serve as an acoustic barrier to one rotating machine which generates an air borne and structure borne sound and vibrations on a certain frequencies. This excitation energy is transmitted to the steel structure and might cause the oscillations of the structure. Depending on the frequency of the source of excitation, oscillations of the structure may occur at one of its natural frequencies, which depends on the physical characteristics of the structure - shape, dimensions, materials, grounding conditions, as well as other structural parameters. If it happens that excitation frequencies and the natural frequencies of the structure coincide to each other, a resonant oscillation of the structure will occur. To avoid the resonant oscillation of the structure, it is necessary the structure be designed such a way that its natural frequencies are not in the operating frequency range of the source of vibration. The investigated steel structure is subjected to mass and stiffness changes due to inserting some additional elements. The change of these physical characteristics of the structure can lead to change of its natural frequencies. To investigate dynamic behaviour of overall structure, a numerical model was set by FEM analysis and experimental analysis was done using modal test and bump test.
Deformation state of the load-bearing structure of a four-column the press
Authors: Todic M , Golubović-Bugarski V , Merdanić M , Latinović T
Published: July 2023

During the operation of each machine, the deformation and stress state of its supporting structure is directly related to the load. The load intensity ranges from the minimum to the maximum value and is a function of nominal force, torque, and kinematic-dynamic values of moving and executive assemblies during the machine operation process. The intensity of deformations is also a function of the shape and type of the supporting structure. However, although the supporting structure is reliable, which refers to its integrity, the production of a quality workpiece (product) does not have to be reliable. Therefore, it is important that the deformation states of the supporting structure be in the appropriate tolerance field, regardless of the intensity of the load. If the intensity of deformations is outside a certain field, it will directly affect the quality of the workpiece that is made on the subject machine. It is known that load-bearing structures can be of open and closed types, load-bearing structures of closed type are used for higher loads and larger workpiece dimensions. By installing sensors on the elements of the supporting structure with accompanying measuring chains in real-time, the deformation state of certain elements or places on the supporting structure can be monitored, based on which the reliable quality of the workpiece can be influenced.
Management of the process of moulding-casting a steel part in order to optimize it
Authors: Josan A , Pinca-Bretotean C , Ardelean E , Ardelean M
Published: July 2023

The foundry industry occupies an important position in the manufacture of castings, both through the existing production capacities and through the remarkable achievements registered in various fields and industries. The goal of steel foundry industry leaders is to meet the demands of both the entire market and individual customers, to develop new products, to improve available technologies, and to implement new “green” projects while optimizing all processes in the foundry. In this context, this paper presents the possibility of optimizing the process of moulding-casting a steel part that can be used in various industries (mechanics, machine building, mining etc.). The non-conformities of the current moulding-casting technology are identified and actions are proposed to remove them. By applying changes in technology, the rejects registered in the industrial practice is significantly reduced, the quality of the production process is improved, which is reflected in the costs of the enterprise.
Sustainable development indicators in the steel industry
Authors: Fărcean I , Proştean G , Socalici A
Published: July 2023

The sustainability indicators of the steel industry, developed by World Steel, measure the performance of sustainability in the social, economic, and environmental fields. They provide a wide perspective on the effects of steel plants. The activity of measuring and monitoring indicators makes significant contributions to the process of implementing and increasing sustainability in the steel sector. Most steel companies voluntarily provide sustainability data, including CO2 emissions and the frequency of accidents over time. The article presents an analysis of the indicators of steel companies, based on data provided by the World Steel Association. Particular attention was paid to the pandemic period, the period that had a different influence on the indicators analyzed.
Wave Load and Strength Analysis of Truss-Floating Box Aquaculture Vessel
Authors: Zhang Yuchen , Zhang Zhaode , Xu Peng
Published: July 2023

There are no specific codes or rules for designing a new truss-floating tank aquaculture vessel developed in recent years. Moreover, relevant rules for ships and offshore structures are usually referred to in different design stages. However, the floating way and the structure of the truss-floating tank aquaculture vessel are different from those of any ship or offshore platform. According to the code of ship or ocean engineering, there will be significant errors in the design. Firstly, loads of vessels at different sea conditions are calculated using SESAM software. The stresses of the truss-floating tank aquaculture vessel are numerically simulated in accordance with the maximum loads. Furthermore, the global longitudinal strength can be evaluated. The sensitivity of the vessel’s strength to wave parameters is analysed. The research results can provide a valuable reference for designing a truss-floating tank aquaculture vessel.
Corrosion Behavior and Simulation Analysis of Silicate Adhesive under High Temperature and Abrasion-Acid Environment
Authors: Gao Ying , Zhao Yuhang , Lin Jing , Li Yifan , Chang Ning , Miao Jiabing , Li Shichun
Published: July 2023

For studying the corrosion behavior and simulation analysis of silicate adhesive under high temperature and abrasion-acid environment, the corrosion behavior of silicate adhesive was tested with mechanical compression, scanning electron microscopic and X-ray diffraction (XRD), and analyzed under high temperature with finite element modeling. The results showed: under high temperatures and the abrasion-acid environment, the solid filler in the adhesive network structure will be exposed with the effect of particle wear. This will lead to a corrosion reaction between some fillers and hydrochloric acid, making dissolution loss. Large hollow holes will be formed at the loss part with the deepening of corrosion, the internal interconnection will occur, and the compression fracture curve characteristics of porous materials will appear, which will greatly reduce the compression strength of the materials. In special environments (temperature 200°C, flow rate 2m/s, and 31% concentration acid solution), hydrochloric acid corrosion is the control factor of silicate adhesive degradation.
Effect of ultrasonic surface rolling on fretting wear behavior of GCr15 steel
Authors: Sun Xinhua , Zhang Mingyuan , Xia Dianxiu , Wang Shouren , Zhang Yunhe , Cai Meigui , Si Guyi , Li Shuqi
Published: July 2023

Bearings are susceptible to fretting wear between the rolling element and the collar, which affects the normal service of bearings. In order to improve the fretting wear performance of GCr15 bearing steel, ultrasonic surface rolling treatment was performed on GCr15 steel under different static pressures and passes, and the fretting wear test was then carried out. Test results showed that the surface roughness was decreased and the microhardness was increased after ultrasonic surface rolling treatment. With an increase in static pressure and passes, the roughness decreases and the microhardness increased. Besides, a lower steady friction coefficient and fretting wear volume were obtained with the specimens performed by ultrasonic surface rolling treatment. With an increase in static pressure and passes, the wear volume and steady friction coefficient decreased together. Furthermore, the mechanism of fretting wear changed from severe adhesive wear, fatigue wear, and abrasive wear to abrasive wear and slight adhesive wear due to the application of ultrasonic surface rolling treatment.
Influence analysis of anti-spatter spray on welding process and weld properties
Authors: Ji Ang , Zhang Liping , Peng Genchen
Published: July 2023

Based on the accumulation situation of anti-spatter spray in actual manufacturing, butt joints are implemented to analyze the state changes of two types of anti-spatter spray and their effect on arc stability, molten pool fluidity, and weld performance. The results show that the fluidity of water-based anti-spatter spray is significantly better than that of oil-based anti-spatter spray in the welding process, resulting in a large accumulation near the arc suppression position. This causes strong fluctuations in the arc and molten pool, while the oil-based anti-spatter spray can reduce the spreadability of the molten pool near the bevel. In terms of weld performance, oil-based anti-spatter spray reduces the plasticity of the weld, and the average elongation of the tensile specimens of the corresponding joint is 37% lower than that of the joint without anti-spatter spray. The rapid evaporation of the water-based anti-spatter spray leads to faster cooling of the weld, resulting in a narrow range of hardened microstructure in the heat-affected zone. Therefore, an apparent increase in microhardness at the corresponding location.
Shear Strength of Honeycomb Sandwich Panel with Impact Damage
Authors: Chen An , Zang Weifeng , Li Lei
Published: July 2023

Impact damage may reduce the mechanical property of honeycomb sandwich composites. In this paper, the impact damage and post-impact shear behavior of honeycomb sandwich plates are studied experimentally. The same impact damage energy was applied to all six test specimens. The damage region and depth of the impact crater were measured by using equipment. Shear tests were conducted on intact and damaged specimens to compare their strain fields and failure modes. The results show that there were no buckling phenomenon in the skin occurred both in intact and damaged specimens during the whole shear experiment. The failure mode of the pristine specimens is different from that of damaged specimens. The shear failure load after impact decreases by 17.1% compared to the non-impact panel. This leads to the conclusion that the impact damage worsens the mechanical property of the honeycomb composite panel and has a great effect on it.
The Influence of Wire Diameter Uniformity on the Quality of Fiber Optic Wire Package
Authors: Li Xiaodong , Meng Lei , Yan Ying , Zhou Ping
Published: July 2023

The fiber optic wire package is the core component of fiber optic guided rockets. Due to the non-uniformity of the fiber optic wire diameter, the winding process is prone to winding defects, which affects the missile launch process. In this paper, a finite element simulation model for the winding process of the fiber optic wire package is established. The accuracy of the simulation model is verified by comparing it with the analytical model for the contact pressure between fiber optic layers. Then finite element models considering the wire diameter tolerance are established to analyze the effect of diameter uniformity on the winding quality of the fiber package. The results show that the stress distribution of a fiber optic package becomes increasingly uneven with increasing wire diameter non-uniformity, and the structural stability of the package decreases. The edge fibers of a 20-layer optical fiber package are easily extruded when the deviation from the nominal diameter is more than 3%. This study helps to guide the manufacturing accuracy of optical fibers and improve the structural stability of the wire package.
Feasibility Study on the Wheel Set Wear Prediction Based on Simulation Analysis
Authors: Li Ze
Published: July 2023

For studying the influencing factors of wheel set wear on high-speed trains, a large number of simulation analyses have found that line conditions, speed, tread profile, adhesion coefficient, contact geometry, and other factors have varying degrees of impact on wheel wear. However, based on the difficulty of the wheel set dynamic measurement, it cannot be directly verified. By establishing a rigid-flexible dynamic model for high-speed trains, the correlation between wheel pair wear and wheel rail load under different working conditions was simulated and analyzed. A dynamometer wheel set is used to measure wheel set loads. The results show that there is a strong correlation between wheel and rail wear and wheel set load under different operating conditions, and the actual wheel set load is significantly affected by the measurement line. The simulated wheel rail load is similar to the measured load distribution characteristics. Therefore, it is obviously feasible to conduct wheel set wear simulation analysis based on measured track irregularity data, but it also puts forward higher requirements for measured track data.
Study on dynamic mechanical properties of tungsten copper alloy and application of shaped charge
Authors: Huang Zeyang , Huang Zhengxiang , Zu Xudong
Published: July 2023

The tungsten-copper alloy liner has better performance than the copper liner. In order to better study the jet forming and penetration characteristics and dynamic mechanical properties of tungsten-copper alloy-shaped charge liner, this paper uses a multi-functional mechanical experimental machine and a Hopkinson bar device to carry out quasi-static tensile and dynamic impact tests, respectively, and fit the Johnson-Cook constitutive equation. The obtained parameters are used to carry out numerical simulations and compared with the experiment. The results show that the stress of the dynamic impact curve is higher than that of the quasi-static stress, and the strain rate strengthening effect is more obvious. There is an adiabatic temperature rise at the strain rate and an obvious thermal softening effect at different strain rates. At the highest strain rate, it shows an obvious strain rate strengthening effect and obvious plasticizing effect, and the tungsten-copper alloy has a certain sensitivity to strain rate. The precision of the Johnson-Cook constitutive model is higher, and it can better describe the plastic flow stress of tungsten-copper alloy at a high strain rate. When the parameters of the fitted Johnson-Cook model are used in the numerical simulation, the error between the numerical simulation and the actual is small. The obtained Johnson-Cook model and dynamic mechanical properties can help the follow-up study on the influencing factors of tungsten-copper jet forming and fracture, including the effect of material strength on injection instability, the integration of the shear band model with hydrodynamics, and the comparison of injection molding penetration with copper liners provide relevant data.
Influence of different alloy elements on the color of copper alloy
Authors: Zhou Liyan , Sun Wei
Published: July 2023

In this paper, Zinc, Aluminium, Nickel, Tin, and Iron are chosen as alloy elements to investigate the influence of different alloy elements on the color of copper alloy. The elements in each experimental group were designed by the orthogonal experiment method. The alloy was prepared by the non-vacuum smelting method. The color of the alloy was determined by spectrophotometer and CIE1976L *a*b* color system. The influence of several common alloy elements on the color of the copper alloy was studied. The results show that the content of Zn had a significant effect on the red-green value of “a”, and with the content of Zn increasing from 10wt% to 16wt%, the value “a” decreased by 2.3. The content of Ni had a significant effect on the value of the blue-yellow value of “b”, and with the content of Ni increasing from 0.5wt% to 2.0wt%, the value “b” decreased by 3.5.
Deformation localization behavior research of AZ31 magnesium alloy under impact load
Authors: Huang Xinting , Hou Jie , Lin Biaozhi , Li Mengmei , Jiang Bingchun
Published: July 2023

The dynamic mechanical properties of AZ31 magnesium alloys were analyzed under different strain rates by using a separated Hopkinson pressure bar system. The microstructure of the specimens was observed by optical microscopy. The results show that the dynamic yield strength of AZ31 magnesium alloy is insensitive to the strain rate. The compressive strength is increasing and shear deformation localization behavior is more obvious with the increase in the strain rate. Meanwhile, the temperature within the shear band is about 241 k and meets the twinning dynamic recrystallization temperature. Temperature rise promotes the grain refining effect.
Effect of Heat Treatment on Microstructure and Properties of Quenched and Tempered Steel with High Vanadium Contents
Authors: Wang Tieli
Published: July 2023

After heat treatment, the microstructure of quenched and tempered (Q&T) steel with high vanadium (V) content was characterized using metallographic and scanning electron microscopes (SEM). The proto-austenite grains of the tested steel were compared at different quenching temperatures, and the precipitation behavior of precipitates and matrix microstructure characteristics at various tempering temperatures were studied. Tensile properties and low-temperature impact toughness of the tested steel with different heat treatments were measured using an electronic universal testing machine and an impact testing machine. The findings indicate that as the quenching temperature increases, the size of the proto-austenite grains gradually increases. When the quenching temperature surpasses 920 °C, the size of the proto-austenite grains obviously increases. With a constant tempering temperature, an increase in quenching temperature results in a decrease in the size of precipitates. With a constant quenching temperature, an increase in tempering temperature results in an increase in the size of precipitates. Therefore, the tested steel quenched at 920 °C for 1 hour and then tempered at 630 °C for 1.5 hours would obtain excellent comprehensive mechanical properties, with a tensile strength of 1233 MPa and a low-temperature impact value of 64 J.
Characteristics and properties of plasma electrolytic nitrocarburizing Ti (C, N) coatings on Ti6Al4V alloy
Authors: Hu Zongchun , Xie Faqin , Xu Weichang , Wu Yake , Bi Yingpu
Published: July 2023

Titanium carbonitrides Ti(C,N) coatings were prepared by plasma electrolytic nitrocarburizing in an electrolytic solution containing ammonium nitrate, glycerol and ethanol. The coating consists of an outer compound layer and an inner diffusion layer with a total thickness of about 100μm. The compounds consist of Ti(C,N) and amorphous TiO2. The corrosion current density of the coating is almost an order of magnitude lower than that of Ti6Al4V substrate in 3.5% NaCl solution. The hardness of the coating is up to 2200HK0.025, which is 5~6 times greater than that of Ti6Al4V alloy. The coating itself is worn very slightly while the counter ball suffering serious abrasion during sliding against the SAE52100 counter ball. The PEN/C coating enhances the hardness, corrosion and abrasive resistances of Ti6Al4V alloy substantially.
Nationwide projections of heat- and cold-related mortality impacts under various climate change and population development scenarios in Switzerland
Authors: de Schrijver Evan , Sivaraj Sidharth , Raible Christoph C , Franco Oscar H , Chen Kai , Vicedo-Cabrera Ana M
Published: July 2023

Climate change and progressive population development (i.e., ageing and changes in population size) are altering the temporal patterns of temperature-related mortality in Switzerland. However, limited evidence exists on how current trends in heat- and cold-related mortality would evolve in future decades under composite scenarios of global warming and population development. Moreover, the contribution of these drivers to future mortality impacts is not well-understood. Therefore, we aimed to project heat- and cold-related mortality in Switzerland under various combinations of emission and population development scenarios and to disentangle the contribution of each of these two drivers using high-resolution mortality and temperature data. We combined age-specific (<75 and ⩾75 years) temperature-mortality associations in each district in Switzerland (1990–2010), estimated through a two-stage time series analysis, with 2 km downscaled CMIP5 temperature data and population and mortality rate projections under two scenarios: RCP4.5/SSP2 and RCP8.5/SSP5. We derived heat and cold-related mortality for different warming targets (1.5 °C, 2.0 °C and 3.0 °C) using different emission and population development scenarios and compared this to the baseline period (1990–2010). Heat-related mortality is projected to increase from 312 (116; 510) in the 1990–2010 period to 1274 (537; 2284) annual deaths under 2.0 °C of warming (RCP4.5/SSP2) and to 1871 (791; 3284) under 3.0 °C of warming (RCP8.5/SSP5). Cold-related mortality will substantially increase from 4069 (1898; 6016) to 6558 (3223; 9589) annual deaths under 2.0 °C (RCP4.5/SSP2) and to 5997 (2951; 8759) under 3.0 °C (RCP8.5/SSP5). Moreover, while the increase in cold-related mortality is solely driven by population development, for heat, both components (i.e., changes in climate and population) have a similar contribution of around 50% to the projected heat-related mortality trends. In conclusion, our findings suggest that both heat- and cold-related mortality will substantially increase under all scenarios of climate change and population development in Switzerland. Population development will lead to an increase in cold-related mortality despite the decrease in cold temperature under warmer scenarios. Whereas the combination of the progressive warming of the climate and population development will substantially increase and exacerbate the total temperature-related mortality burden in Switzerland.
Pocket parks-a systematic literature review
Authors: Dong Jing , Guo Ruonan , Guo Fei , Guo Xiaoming , Zhang Zhen
Published: July 2023

The rapid process of urbanization and climate change have resulted in socio-environmental issues that necessitate viable intervention strategies to create green, sustainable, healthy, and livable built environments. One effective method of achieving this is through the development of pocket parks. Although several studies have explored the benefits and design principles of pocket parks, there is a lack of systematic and quantitative understanding, which could influence the decision-making process for the proper adoption of pocket parks. In view of this knowledge gap, this study employs bibliometric methods and critical review to quantitatively analyze and systematically review 276 papers published in the Web of Science and Scopus databases between 1977 and 2023. Firstly, a bibliometric analysis is conducted, providing a comprehensive overview of research on pocket parks. Secondly, a detailed critical review is conducted from three major perspectives: influencing factors, design methods, and benefits of pocket parks. Finally, the research trends and future directions are discussed. The results indicate that (a) pocket park development takes various forms, with a growing number of articles published each year. However, research on this topic is primarily concentrated in the United States and China, with significant knowledge gaps remaining globally. (b) The utilization of pocket parks is affected by various factors, including internal, external physical, and socio-economic factors. The mechanisms of these factors and their interactions demand deeper understanding. (c) There is a need to conduct an in-depth exploration of planning methods for pocket parks, and planning and design methods in different country contexts can be expanded and compared. (d) Further research is needed to compare the benefits of pocket parks in different climatic zones in terms of depth and width. The outcome of this study can contribute to the body of knowledge on pocket parks, foster their wider acceptance, and help urban planners, practitioners, policy makers, and government managers apply them more effectively in resilient and livable cities of the future.
Short-term extreme heat at flowering amplifies the impacts of climate change on maize production
Authors: Luo Ning , Mueller Nathan , Zhang Yi , Feng Puyu , Huang Shoubing , Liu De Li , Yu Yonghong , Wang Xingya , Wang Pu , Meng Qingfeng
Published: July 2023

Extreme weather poses a threat to global crop production, food security and farmer livelihoods. High temperatures have been identified as detrimental to crop yields; however, how heat stress during the critical flowering stage will influence future maize (Zea mays L.) yields remains unclear. Here, we combined statistical and process-based models to assess impacts of short-term extreme heat at flowering on Chinese maize yield under climate change. We showed that heat around flowering has a stronger impact on yields than heat at other times in the growing season, especially for temperatures >30 °C. Heat stress during flowering was responsible for 23% of total yield loss from extreme degree days (EDDs) in 1990–2012. An improved process-based model (Agricultural Production Systems sIMulator (APSIM)-maize) incorporating a grain-temperature function was then applied and indicated that extreme heat at flowering amplified the impacts of climate change on maize production compared to the original model. The improved APSIM-maize predicted an 8.7% yield reduction across the Chinese Maize Belt as EDDs increased more than quadrupled at the end of the century (2070–2099) under a high emissions pathway (SSP585) in comparison with the baseline period (1990–2019). Our study highlights the importance of extreme heat at flowering on maize yield and can inform farmers and policy makers on adaptive measures as well as providing a reference for other crop areas facing similar challenges.