bluuebunny/crossref_metadata_2025 huggingface dataset:
Projectile-Artillery-Propellant Coupled Optimization Design Method of Artillery Weapon Systems
Authors: Shen Qing-ming , Yan Li-jun , Zhao Jian-zhong , Gao Ying , Yuan Yong-qiang , Wang Er-liang , Zhang Shi-ming , Ma Chao
Published: May 2023

The artillery weapon system is a complex system of great non-linearity. There are many factors and their coupling relationship affecting the firing performance of artillery, and the key factor positioning is difficult. How to improve the firing performance of artillery through optimization is a challenge. The current optimization method considers less coupling factors. To approach this challenge, a projectile-artillery-propellant coupled optimization design method is proposed, where a multidisciplinary coupling of projectiles, artillery and propellant is proposed and used to construct an optimization model, and the minimum initial disturbance is taken as the optimization objective. The simulation results show that at the moment when the projectile exist the muzzle, the optimized muzzle vibration displacement is reduced by 47.6%, the muzzle vibration speed is reduced by 33.4%, the average nutation angle is reduced by 63%, the average nutation angular speed is reduced by 27%.
Research on the Vibration Response of an Aircraft Gun Muzzle Based on Nonlinear Finite Element
Authors: Tian N , Zhao J , Wang K , Wang K , Du X , Liu Z
Published: May 2023

The muzzle vibration response of an aircraft gun is one of the key factors affecting the firing accuracy of the aircraft gun. In order to study the muzzle vibration response of an aircraft gun, based on the basic theory of the nonlinear finite element method, the nonlinear finite element dynamics simulation model is established by considering the nonlinear factors which are the contact and collision between the gun aircraft and the cradle, the contact and collision between the elevating gear arc and gear, and the slide clearance between the aircraft gun and the cradle, etc. The muzzle vibration response is characterized by the linear displacement and linear velocity of the center point of the aircraft gun, and its dynamics is obtained through numerical calculation and simulation. The correctness of the dynamics simulation model of the aircraft gun muzzle vibration is verified by setting up verfication bench. The results show that the established nonlinear finite element dynamic simulation model can be used to predict the muzzle vibration response of the aircraft gun, and at the same time, by changing the slide clearance between the aircraft gun and the cradle, the effect of clearance on the muzzle vibration response is investigated. Additionally, it can be seen that reducing the slide clearance can improve the firing accuracy of the aircraft gun while ensuring the machining assembly and mechanism movement.
Summary and Prospect of Artillery Recoil Reduction Technology
Authors: Shen Qing-ming , Wang Guo-bo , Zhao Jian-zhong , Meng Chao , Yuan Yong-qiang , Wang Er-liang
Published: May 2023

Modern warfare has an urgent need for high-mobility and powerful artillery. However, the mobility and power of artillery are a contradiction. Recoil reduction technology is an important technical way to solve the contradiction between mobility and power. At present, there are many types of recoil reduction technologies, and the technical maturity and engineering application value of various technologies are different. For the development of new high-mobility and high-power artillery, which recoil reduction technology to adopt is a challenge. This article classifies and researches recoil reduction technology from the perspective of recoil energy dissipation. Based on the research and comparison of the basic principles, technical characteristics and application prospects of recoil reduction technology, it is concluded that the soft recoil technology using the principle of external neutralizing momentum is the best technical approach for the artillery system to realize high-mobility and high-power, where the potential application prospects of this technology in direct-target weapons are analysed.
Study on the Method of Identifying Aircraft Parameters Based on Thrust Coupling
Authors: Zhang Yao , Gao Xiaobo , Qiao Hao , Mao Rui , Lou Jiang , Li Geng
Published: May 2023

The application of the actual flight data of aircraft into the post identification and analysis of its parameters not only helps verify the model on ballistic parameters, but is also of utmost significance for assessing the accuracy of launching missiles and projectiles. To address the issue of coupling of time-varying parameters such as thrust and mass flow, the engine parameters are separated from the aerodynamic parameters based on the ballistic model of combustion chamber. To address the issue of the intersection between constant parameters and time-varying parameters, the initial mass deviation and the thrust deviation of aircraft are obtained through the global average approach. As shown by the simulation results, this method effectively enables the identification of parameters, and has theoretical significance and practical value during engineering application.
Research on Effect of Initiation Detonation Method on Fragment Velocity Distribution
Authors: Jin Wang , Yan-wen Xiao , Ao-xin Liu , Chao Ge
Published: May 2023

To enhance the damage effect of focusing warhead, the investigation about the scattering behavior of focusing warhead is conducted. Based on the momentum method and the detonation wave theory, the influence of initiation detonation methods and curvature radius of the charge on fragment velocity is analyzed. The fragments velocity distribution models of the end-initiated, the center-initiated and the two ends-initiated are obtained. Numerical simulation shows that fragments velocity distribution and the propagation of the detonation wave of numerical simulation results have a good fit with the theoretical model. It is shown that fragments velocity is higher in the middle and low on both sides. When it was end-initiated, the location where the fragment velocity reaches the maximum was 18.6cm from the initiation end. When it was center-initiated, the maximum fragment velocity appeared at the center of the projectile axis. When it was two ends-initiated, the maximum fragment velocity appeared symmetric about the center line of the projectile axis. With increasing of the curvature radius of the circular charge, the maximum velocity of the fragments increased.
Study on Cable Network Design of Small Tactical Missile
Authors: Xi X W , Zheng H X , Li P , Zuo F , Yang Q , Zheng Y
Published: May 2023

This paper studies the cable network design of small tactical missile from two aspects: hardware design and soft design. The hardware design of cable network mainly includes the design of electrical connector, transmission line, cable sheathing and other accessories, while the soft design involves signal redundancy design, error prevention design and electromagnetic compatibility design. The research results set up a framework for the subsequent design and manufacture of cable network, which has a certain guiding significance.
Preparation and Structural Behavior of High-Performance PBO Fibers
Authors: Zhang DB , Liu ZF , Zhong WH , Qin ZM , Xiao ZX
Published: May 2023

To improve the dispersion ability of monomers in the high-viscosity PBO pre-polymerization system, a new large-capacity mixing paddle for PBO pre-polymerization reaction was designed. Through simulated calculation, it was found that the new mixing paddle has good dispersion effect and produced PBO polymer whose intrinsic viscosity was 37.5 dL/g, number-average molecular weight was 92700, and degree of polymerization was 396. Then the PBO fibers were prepared by the dry jet wet spinning technique. The morphology analysis showed that the PBO fibers were well formed, with a diameter of 14 µm. The infrared spectrum analysis verified the structure of PBO fibers. The mechanical test showed that the tensile strength of PBO fibers was 5.04-5.76 GPa and the elongation at break was 3.93% - 4.54%, which means they have good mechanical properties.
Analysis of the Ballistic Performance and Mechanism of Soft Bulletproof Layers under the Impact of Multiple Lead Core Bullets
Authors: Wang XC , Wang W , Peng G , Chen CX , Gao B , Feng JC , Zhang B
Published: May 2023

The soft bulletproof layers as key protective component of a bulletproof vest against pistol bullets, are subject to multiple bullets in both the ballistic resistance test and the real combat. To analyze the influence of multiple impacts on the ballistic performance, the ballistic tests are conducted on the soft bulletproof layers. The ballistic performance of multiple ballistic impacts is compared in the same test condition, and the influence of mechanical properties of materials, boundary effects, angular effects and structural changes caused by impact are studied. It is concluded that the ballistic protection performance of the multiply structure of soft bulletproof layers not only depends on the ballistic protection and energy absorption performance of the single-layer fabrics, but also is closely related to the ballistic protection synergy between the soft bulletproof layers; from the perspective of fibers and single-layer fabrics, the ballistic protection and energy absorption are determined by main factors such as elastic modulus, tensile strength, strength of materials and breaking strain, which also have the coupling effects; for the structural design of multiple soft bulletproof layers against lead cored bullets, it is necessary to comprehensively study the influence of mechanical properties of the projectile and target materials, boundary effects, angular effects and structures & forms on the ballistic protection performance.
Hygrothermal Ageing and Life Prediction of Carbon Fiber Composite Structural Members on an Aircraft
Authors: Zhang HY , Kong GQ , Wang ZS , Wang J , Li JY , Chen QX , Wei HZ
Published: May 2023

The mechanism of hygrothermal ageing of carbon fiber composite structural members was analyzed in terms of changes in appearance, infrared spectra, mechanical properties and internal structure under hygrothermal conditions. Based on ASTM F1980-07, predicted values for the storage life of the structural members were obtained. The results show that after hygrothermal ageing, the surface of the structural member remains smooth, with no exposed fibers, degradation or ageing, and that the internal structure and mechanical properties are stable. The life predictions calculated according to the standard are in good agreement with the design life of the actual members.
Research on Properties of 450°C Resistant Polyimide Composites
Authors: Gao SZ , Huang ZQ , Wang XL , Li DY , Wang J , Luo CH , Qi FJ , Xu XY , Ma KB , Yu G
Published: May 2023

Carbon fiber/polyimide composites were prepared by high temperature molding process with carbon fiber, 450 °C resistant polyimide resin and related additives as raw materials. Effects of prepreg resin content, porosity and post-treatment temperature on properties of composites were studied, and fracture shape was analyzed. Results show that high temperature shear properties of carbon fiber can be improved by more than 50% after removing sizing agent, and mechanical properties of composites are the best when the resin content of prepreg is (30 to 40)%. Retention rate of mechanical properties of composites is more than 90% when porosity is less than 1.5%. And mechanical properties decline sharply when porosity is greater than 2%. Carbon fiber/polyimide composites have good high temperature resistance below 450°C, and mechanical properties of composites can be improved to a certain extent after treatment at room temperature to 300°C. Fracture morphology analysis shows that high temperature mechanical properties of composites depend on heat resistance of resin and matching between resin and fiber.
Main Role of New High Strength, Toughness and Low-Density Steel in Artillery Lightweight
Authors: Hu S L , Cen Y M , Zhou H K , Tian Y J , Ma L C , Cai B , Hu J
Published: May 2023

The new high strength, toughness and low density steel is a new generation of lightweight material with high protection, which is based on the theory of lattice dilution and lattice distortion and is manufactured by adding light elements to reduce its density. Furthermore, after impact process, the composite effects such as transformation induced plasticity (TRIP) effect, twinning induced plasticity (TWIP) effect, microbands induced plasticity (MBIP) effect and phase transformation precipitation occur in the microstructure. The specific strength and specific stiffness are better than those of aluminum, magnesium and titanium alloys, and the modulus is 3 times that of aluminum alloy and 2 times that of titanium alloy. Preliminary research shows that the application of low density steel in artillery system can greatly reduce the production cost. On the basis that all technical and tactical indexes meet the design requirements, it can realize lightweight, long-distance strategic delivery and battlefield real-time repair.
Research on the Application of Composite Materials in Artillery Weapon
Authors: Fan T F , Zhou J Y , Tian Y F , Ma J J , Huang K
Published: May 2023

For artillery weapons, improving range or improving mobility is an eternal contradiction, so lightweight design is the key method to solve this contradiction. The application of composite material can improve the degree of artillery lightening and enhance the comprehensive combat effectiveness of artillery, so as to adapt to the requirements of modern war. This paper analyzed the characteristics, performances and capable application areas of common-used composite materials in artillery, and introduced its recent applications both home and abroad in barrels, turrets and other structural parts, and focused on the research on design methods and key technologies of its applications in self-propelled artillery. It can be taken as a guide in reasonable application of composite materials in artillery weapons.
Research of Ceramic Aluminum New Material and Its Application on Certain Naval Gun
Authors: Liu D , Meng C , Ma C , Yuan Y Q , Gu Z Y , Han R F , Gao Y
Published: May 2023

The ceramic aluminum new material is a kind of high performance material, which has attracted much attention due to their excellent properties such as high elastic modulus, good wear-resistance and high strength. These properties have made ceramic aluminum materials attractive candidates for various application fields. As the weapons equipments have entered the golden development period, the demand for high performance composite materials is crucially strong. It was estimated that the new materials was used to produce the brackets and cradles on certain naval gun, which account for more than 31% of all gun materials. The results showed that the properties of the ceramic aluminum new material were better than those of the conventional cast aluminum and matrix aluminum alloy. Under the condition of the same structure, the weight of the ceramic aluminum new material was about 6.5% and the maximum deformation was about 15.5% less than that of the ordinary aluminum alloy. Under the condition that the maximum deformation was basically the same and the stress was not considered, the weight of ceramic aluminum alloy was about 6.3% less than that of the ordinary aluminum alloy.
Preparation of Fluorine Certified Reference Material for Fluoroether Rubber
Authors: Hou QQ , Xu F , Dong YaZ , Zhang WS , Zhu TY , Liu X , Xun QN , Ji KJ
Published: May 2023

High-pressure free radical emulsion polymerization was used to prepare the fluorine certified reference material candidates for fluoroether rubber. Ion chromatography method and high performance liquid chromatography were adopted for the determination of the certified reference material, and various sources of uncertainty in the determination process were analyzed and calculated to gain the expanded uncertainty by synthesis. The homogeneity of the certified reference material was checked by F test and the stability was investigated by t test. The results show that the prepared fluorine certified reference material for fluoroether rubber has accurate value and good homogeneity and stability.
A Chamber Pressure Prediction Method Based on Strain Measurement of Composite Barrel Recoilless Guns
Authors: Li Z Y , Tao G , Ren B X , Wang X F
Published: May 2023

To predict the chamber pressure of positions corresponding to the strain data of the gun barrel’ outside walls, this study measures the chamber pressure and strain of different positions in a recoilless gun, and proposes a chamber pressure calculation method which is based on strain measurement of cylinder walls using the single-layer thin-walled cylinder theory and the plane strain-elastic stress solution for multi-layer orthotropic cylinders. Experimental results showed that the deformation of the recoilless gun at different positions was caused by varying factors. Specifically, chamber deformation was attributed to the expansion of high-pressure propellant gas, showing a strain curve similar to that of chamber pressure. The deformation of the barrel part between the chamber throat and the muzzle was first caused by band engraving and then by the expansion of high-pressure propellant gas. If the effect of band engraving was neglected, the changes of chamber pressure there were found to be well in line with the chamber deformation caused by propellant gas expansion. The calculation results revealed that the relative errors between the chamber pressure values predicted by the proposed method and the measured ones were in the range of 0.82%-7.88%, suggesting that the proposed method can effectively predict chamber pressure. The calculation error at the chamber position was large, reaching 7.88%, due to the neglect of the gap between the cartridge case and the chamber’s inside walls. The pressure in the barrel part between the chamber throat and the muzzle was satisfactorily predicted, with a minimum error of 0.82% and a maximum error of only 5.89% at the muzzle.
Mechanical Properties of a Hybrid Composite with Ternary Laminated Structure
Authors: Qi YY , Xue YJ , Wang BC , Xu HM , Kong LM
Published: May 2023

A hybrid composite reinforced by aramid, glass and carbon fibers and processed with integrated vacuum infusion is studied in this paper. Reasons why the composite suffers from warpage after post-curing are analyzed. Such deformation is restrained by adjusting the thickness ratio of the fibers. Results indicate that with a constant areal density, the minimum deformation is 0.28 when the thickness ratio of the surface layer to the back layer is 1.46.
Ignition Performance of SCB/Pb•BaTNR
Authors: Liu LJ , Wang ZJ , Li TT , Zhang T , Wen C , Guo XR , Tang L , Wang BY , Zhang X
Published: May 2023

Polysilicon thin-film semiconductor bridges (SCB) and Pb•BaTNR primary explosives are selected to prepare SCB/Pb•BaTNR samples, and their ignition performance is tested. The test results show that the SCB/Pb•BaTNR samples were ignited random when the ignition energy provided for SCB is insufficient but aroud critical value. Under different energy-storage capacitance, the voltages that lead to SCB completely gasifying into high-energy plasma are around 21V, indicating that charging voltage is the main factor affecting SCB elements to produce high-energy plasma. Ignition tests are performed on the SCB/Pb•BaTNR samples under the conditions of 47μF/21V, 64μF/21V, and 100μF/21V. The samples are found to ignite reliably, and the action time ranges from 0.17 ms to 0.4 ms, meeting the requirements for high instantaneity.
Modular Design of Missile Electrical System
Authors: Hongxing Zheng , Fei Zuo , Hang Xu , Xiaowen Xi , Shi He
Published: May 2023

Future battlefield requires some new features of tactical missile, such as “plug-and-play” assembly at the field level, intelligent recognition and autonomous reconfiguration. Based on these needs, this paper systematically studies the design of information transmission system on the missile, power supply and distribution of the whole missile, and electric information transmission between function modules of the missile. It finally puts forward the design scheme of missile electrical system with functions like “plug-and-play” assembly at the field level, intelligent recognition and autonomous reconfiguration.
A BeiDou Single-Frequency Pseudo-range Differential Positioning Algorithm Optimized for Trajectory
Authors: Peng Wu , Pengxiang Yang , Shuanhu Yang , Lu Luo
Published: May 2023

This paper proposes a BeiDou differential positioning algorithm for guided munitions. It builds on the traditional differential positioning algorithm, with the tropospheric delay corrected according to the trajectory altitude, which reduces the positioning error caused by the large elevation difference between the rover and base stations. Through simulation and real flight tests, it is verified that the algorithm can effectively improve the differential positioning accuracy of the missile-borne satellite receiver.
Development of Universal Test Platform of Missile Launch and Control System
Authors: Zhou Y Q , Xue X L , Zhao N , Guo Y C
Published: May 2023

This paper proposes a novel hardware and software platform for missile launch and control system based on custom Ethernet bus + modular unit + synchronous clock. It consists of power unit, main control unit, MIL1553B/ARINC429 interface simulation unit, CAN/Flexray interface simulation unit, universal serial interface simulation unit, I/O interface simulation unit, video unit, stabilized voltage supply unit, chassis and other parts. Each unit adopts the modular daisy chain communication, and, through modularization of each unit, realizes the testing of maintenance objects and the expansion of new equipment testing resources in the future. Real-life application shows that the proposed hardware and software platform is reliable and effective.
The Evolution and Development Trend of the Gun Integrated Electronic System Architecture
Authors: Han CW , Gu SH , Zhang GS
Published: May 2023

Over the past 40 years, with the rapid development of gun digital technology, the gun integrated electronic system has experienced the evolutionary development process of discrete, federal, and combined system architecture. The development of the future generation of gun integrated electronic system architecture is still in the research and exploration stage. The research results are relatively few and lack of systemicity. This paper proposes a development model and basic concepts of a one-net architecture for the integrated electronic system of gun, and discusses the system composition of the one-net architecture and the core key technologies that need to be solved.
UAV path recognition and tracking based on image
Authors: Nie C R , Guo J , Tang S J , Qi H B
Published: May 2023

This paper firstly analyzes and establishes the motion model of the quadrotor UAV, and then designs the image recognition and control system scheme for the path tracking task. In the image recognition part, the path information is obtained and the desired position signal is obtained by the steps of image optimization, Hough transformation, determining flight direction, identifying the drop-point area, and the PID control is used in the control system part. From the simulation results and 3D visualization module, it can be seen that the UAV can complete the straight-line flight, curve flight, and landing action well, and the image recognition and flight control scheme designed in this paper has good performance.
Development Status and Prospect of Bionic Ammunition
Authors: Yan Junliang , Zhang Xiang , Liu Qi , Liu Mengyan
Published: May 2023

With the evolution and development of modern war forms, traditional ammunition is increasingly unable to meet the needs of modern battlefield, and various types of special ammunition emerge as the times require. Bionic ammunition is a kind of miniaturized autonomous ammunition based on bionics theory. It has some excellent performances that other ammunition can’t match, such as intelligence reconnaissance, combat assistance, secret killing and so on. The appearance of bionic ammunition will lead the research of new ammunition to a new stage. This paper introduces the concept of bionic ammunition, summarizes the development of this field at home and abroad, and finally puts forward the future trend and existing problems of bionic ammunition.
Review on the Development of Power Field Testing Technology of High-energy Warhead
Authors: Yan ZG , Wu JP , He X , Cui XC , Lv HP , Sun WP
Published: May 2023

With the increase of warhed charge and the development of new energetic materials, a variety of high-energy warheads have been invented, and the power of high-energy warheads has been greatly enhanced. The power distribution of the warhead explosion is extremely complicated in the space-time dimension, which lead to problems for accurately test and characterize the warhead damage power. According to the characteristics of the high energy warhead, this paper summarizes the research status and progress of the damage testing techniques at home and abroad in recent years, such as shock wave field, fragment field and temperature field. It analyzes the new requirements of the high energy warhead for the power field test technology, and provides a reference for further improving the test capability of the high energy warhead.
Reinforcement Learning based position control of shell-fetching manipulator with extreme random trees
Authors: Fan Jiang , Yunpu Zhu , Quan Zou , Manyi Wang
Published: May 2023

The automatic loading system of artillery includes the gun-fetching manipulator, which is crucial. The stability and control accuracy of the manipulator, however, are comparatively subpar when following the position trajectory as a result of the changes in the settings of the permanent magnet synchronous motor. This research suggests a reinforcement learning-based strategy for controlling a gun manipulator’s motor behavior in light of the current scenario. In this algorithm, the state variable is the feedback output of the control variable, and the reward function is utilized to calculate the associated reward value. The reinforcement learning agent then makes decisions based on the environment’s state and reward value, adjusting the manipulator’s trajectory in real-time. By comparing different simulation results, the gun-taking manipulator can achieve more accurate position trajectory control based on reinforcement learning.
Research on Fault Diagnosis Technology of Rotational Shell Magazine based on MSCA and SVM
Authors: Liu Yang , Yadong Xu , Wenkuan Huang , Xianxiang Xie
Published: May 2023

The power unit of self-propelled artillery rotational shell magazine is a vulnerable part in the whole system. Aiming at the problem of magazine fault diagnosis under multiple loads, the method of motor current characteristic analysis and support vector machine is used to diagnose the fault of reducer. Through the establishment of a virtual prototype of a certain revolving shell magazine, the state characteristics of the reducer are analyzed from the perspectives of time domain, frequency domain, time frequency and distribution entropy with the motor phase current as the information source. The support vector machine method is used to train and classify the feature vector set, and the fault diagnosis of a certain rotary magazine reducer is completed.
Research Progress and Prospects of Intelligent Digital Equipment
Authors: Chunmao Ma , Xiaolei Song , Xu Zhang
Published: May 2023

In response to the development trend of unmanned and intelligent weapons and equipment for the future, intelligent digital equipment, as a “digital brain”, can be deeply integrated into various links such as equipment development and upgrading, experimental verification, and operational support, to lead to leapfrog development of the operational support for future intelligent equipment. First, intelligent digital equipment allows the physical equipment to make adaptive adjustments and boost operational efficiency during combat. Second, it helps the equipment build a capability of perceiving its status and thus improves the operational readiness of equipment in normal times. Third, it allows equipment fault isolation for diagnosis and thus improves the completion rate of missions in combat. Fourth, it provides intelligent guidance for operation training and enhances the efficiency of use and training. Fifth, it achieves online upgrading and verification of functionalities, and changes and upgrades the maintenance mode. This paper introduces the concept of digital equipment and the research outcomes concerning digital twin around the world from 2010 to 2020, and reviews the research progress in the United States and China. It presents the problems faced by the research, and puts forward solutions and research prospects.
The Application of Artificial Compound Eye in Precision Guided Munitions for Urban Combat
Authors: Song Yan-feng , Hao Qun , Cao Jie , Liu Qiang-hui , Liu Hao , Li Jie
Published: May 2023

As an ideal visual perception system with miniaturization, multi-aperture, wide field of view, low aberration, infinite depth of field, high efficiency and real-time, bionic compound eye has obvious intelligent characteristics, which provides a new idea for the future intelligent development of precision guided weapons, and has also been highly concerned by the US military. Under the leadership of the military, the United States has carried out a series of studies and achieved a series of results. The strategic position of urban combat in the future is analyzed. The requirements of the U.S. Air Force for the next generation of precision-guided munitions, and also the strategic significance of developing urban combat weapons and equipment is described. The advantages and characteristics of artificial compound eye are briefly described. Mainly discussed a series of WFOV artificial compound eye seeker being studied and developed by the U.S. Air Force for urban warfare, as well as the research and development process. Finally, the development suggestion of the WFOV artificial compound eye seeker is given.
Meteorites in Physics Laboratory
Authors: Montalbano Vera
Published: May 2023

A proposal for a physics laboratory inserted in an interdisciplinary learning path for characterizing meteorites is described. Small meteorites are characterized both qualitatively through magnetic properties and quantitatively with density measurements. Of particular interest is the open problem of measuring an object with a small volume and an irregular shape. From the measurements of immersion in water, which are often very difficult due to the lack of adequate instruments in laboratory, it is possible to face a concrete experimental problem that leads to unusual indirect measurements.
The harmonic driven pendulum as a teaching example of integration of laboratory and computation
Authors: Tufino Eugenio , Oss Stefano , Gratton Luigi
Published: May 2023

We describe an activity developed as laboratory at home during the pandemic period by which it is possible to investigate numerically and experimentally a harmonically driven pendulum with a variable frequency. We realized a prototype using LEGO® bricks and EV3 motor. Because the pendulum undergoes large amplitude oscillations, the motion has been studied by implementing the non-linear numerical model in Python. Students can acquire the experimental data with the software of video analysis and compare them with the numerical model. This approach allows to integrate, at varying levels of complexity, computational and experimental skills into the laboratory practice. The activity also allows a connection with the recent topic of gravitational waves detectors that use pendulums in cascade, as mechanical filters to attenuate the seismic noise.
Focus on conceptual ideas in quantum mechanics for teacher training
Authors: Freericks James K
Published: May 2023

In this work, we describe strategies and provide case-study activities that can be used to examine the properties of superposition, entanglement, tagging, complementarity, and measurement in quantum curricula geared for teacher training. Having a solid foundation in these conceptual ideas is critical for educators who will be adopting quantum ideas within the classroom. Yet they are some of the most difficult concepts to master. We show how one can systematically develop these conceptual foundations with thought experiments on light and with thought experiments that employ the Stern-Gerlach experiment. We emphasize the importance of computer animations in aiding the instruction on these concepts.
Investigating of plasma diagnostics by utilizing spectroscopic measurements of Balmer emission
Authors: Arjmand S. , Anania M.P. , Biagioni A. , Ferrario M. , Del Franco M. , Galletti M. , Lollo V. , Pellegrini D. , Pompili R. , Zigler A.
Published: May 2023

Plasma technology offers revolutionary potential for particle accelerators by enabling the
acceleration of electron beams to ultra-relativistic velocities in a small-scale dimension. The
compact nature of plasma-based accelerators permits the creation of accelerating gradients on the
GV scale. Plasma acceleration structures are created by utilizing either ultra-short laser pulses
(Laser Wakefield Acceleration, LWFA) or energetic particle beams (Particle Wakefield Acceleration,
PWFA), which need to be tailored to the plasma parameters. However, both methods face the
challenge of limited acceleration length, which is currently only a few centimeters. To overcome
this challenge, one approach is to generate plasma within a capillary tube, which can extend the
acceleration length up to approximately forty centimeters or more. Consequently, it is crucial to
characterize the produced plasma in terms of density and geometric structure. Optical emission
spectroscopy (EOS) methods can be employed to measure and characterize the plasma electron density
by analyzing the emitted plasma light. This paper presents measurements of the plasma electron
density distribution for a hydrogen-filled capillary tube using both Balmer alpha
(Hα) and Balmer beta (Hβ) lines. Comparing the
intensities of Hα and Hβ emissions enables more precise
measurements of the plasma electron density and provides additional information about other plasma
properties.
A derivation of the electric field inside MAPS detectors from beam-test data and limited TCAD simulations
Authors: Santra A. , Tal Hod N.
Published: May 2023

Solid semiconductor sensors are used as detectors in
high-energy physics experiments, in medical applications, in space
missions and elsewhere. Minimal knowledge of the electric field
inside the elementary cells of these sensors is highly important for
their performance understanding. The field governs the charge
propagation processes and ultimately determines the size and quality
of the electronic signal of the cell. Hence, the simulation of
these sensors as detectors in different analyses relies strongly on
the field knowledge. For a certain voltage applied to the cell, the
field depends on the specifics of the device's growth and
fabrication. The information about these is often commercially
protected or otherwise very difficult to encode in state-of-the-art
technology computer-aided-design (TCAD) software. In this work, we
show that by taking the top-down approach, combining public
beam-test data and a very limited public TCAD knowledge, we are able
to effectively approximate the 3D electric field function in the
pixel cell of one important and widely used example, namely the
ALPIDE sensor, for simulating the charge propagation
processes. Despite its broad usage worldwide, the ALPIDE field is
not available to the community. We provide an effective field
function, that adequately describes the sensor behaviour without
trying to reconstruct further details about the device or the
details behind its processing. We comment on the process by which
the effective field function is derived with the help of the
Allpix2 software, and on how similar work can be performed for
other devices, starting from the same grounds.
Patterns and drivers of disturbance in tropical forest reserves of southern Ghana
Authors: Wanyama Dan , Wimberly Michael C , Mensah Foster
Published: May 2023

Ghana has retained a substantial area of tropical forests in an extensive network of protected reserves. These forests are impacted by land uses such as logging, mining, and agriculture as well as wildfires. We studied forest disturbance and recovery from 2013 to 2020 using annual maps of forest cover derived from Landsat imagery. Fire-associated disturbance was distinguished using VIIRS active fire data. We used boosted regression trees to model disturbances in closed and open forests as a function of climate variability, human accessibility, and landscape structure. A total of 3562 km2 of forest reserves were disturbed, of which 17% (615 km2) were fire disturbances and 83% (2946 km2) were non-fire disturbances. Of the total disturbed area, 68% was degradation (change from closed to open forest), 28% was open forest loss, and only 4% was closed forest loss. Over the same period, 2702 km2 of forest reserves recovered, with 1948 km2 of these recovering to closed-canopy forests. Fire disturbances were strongly associated with precipitation anomalies and occurred mostly in drier years, whereas non-fire disturbances had weaker relationships with precipitation. Disturbances in closed forests occurred in landscapes where closed forest cover was already low. In contrast, disturbances in open forests were most common in locations with intermediate levels of population pressure from nearby cities and proximity to non-forest land cover. The results support the idea that forest disturbance in Ghana is a multi-stage process involving degradation of closed forests followed by loss of the resulting open forests. Although non-fire disturbance rates are consistent from year to year, sharp increases in fire disturbance occur in drought years. Locations with the highest disturbance risk are associated with measurable indicators of climate, human pressure, and fragmentation, which can be used to identify these areas for conservation and forest restoration activities.
Geometric wave-front set may not be a singleton
Authors: Tsai Cheng-Chiang
Published: May 2023

We show that the geometric wave-front set of specific half-integral-depth supercuspidal representations of ramified

p
p

-adic unitary groups is not a singleton.
RBPLight: a computational tool for discovery of plant-specific RNA-binding proteins using light gradient boosting machine and ensemble of evolutionary features
Authors: Pradhan Upendra K , Meher Prabina K , Naha Sanchita , Pal Soumen , Gupta Sagar , Gupta Ajit , Parsad Rajender
Published: May 2023

RNA-binding proteins (RBPs) are essential for post-transcriptional gene regulation in eukaryotes, including splicing control, mRNA transport and decay. Thus, accurate identification of RBPs is important to understand gene expression and regulation of cell state. In order to detect RBPs, a number of computational models have been developed. These methods made use of datasets from several eukaryotic species, specifically from mice and humans. Although some models have been tested on Arabidopsis, these techniques fall short of correctly identifying RBPs for other plant species. Therefore, the development of a powerful computational model for identifying plant-specific RBPs is needed. In this study, we presented a novel computational model for locating RBPs in plants. Five deep learning models and ten shallow learning algorithms were utilized for prediction with 20 sequence-derived and 20 evolutionary feature sets. The highest repeated five-fold cross-validation accuracy, 91.24% AU-ROC and 91.91% AU-PRC, was achieved by light gradient boosting machine. While evaluated using an independent dataset, the developed approach achieved 94.00% AU-ROC and 94.50% AU-PRC. The proposed model achieved significantly higher accuracy for predicting plant-specific RBPs as compared to the currently available state-of-art RBP prediction models. Despite the fact that certain models have already been trained and assessed on the model organism Arabidopsis, this is the first comprehensive computer model for the discovery of plant-specific RBPs. The web server RBPLight was also developed, which is publicly accessible at https://iasri-sg.icar.gov.in/rbplight/, for the convenience of researchers to identify RBPs in plants.
Increase in False-Positive Fourth-Generation Human Immunodeficiency Virus Tests in Patients With Coronavirus Disease 2019
Authors: Gudipati Smitha , Shallal Anita , Peterson Edward , Cook Bernard , Markowitz Norman
Published: May 2023

Background

We observed an increase in the frequency of false-positive (FP) human immunodeficiency virus (HIV) test results that correlated with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) prevalence. We measured FP rates of laboratory-based fourth-generation HIV antigen/antibody test among those with polymerase chain reaction (PCR)-confirmed infection with SARS-CoV-2 compared with FP rate of those who tested SARS-CoV-2 PCR-negative.

Methods

All patients PCR tested for SARS-CoV-2 within 2 weeks of an HIV fourth-generation assay were selected. Positive HIV fourth-generation assays were reviewed and divided into groups of FP, true positive (TP), and presumptive negative (PN). Variables included age, race, ethnicity, gender, pregnancy, and Coronavirus Disease 2019 (COVID-19) immunization status. Associations with positive SARS-CoV-2 tests were assessed using linear logistic regression. Multivariate logistic regression was used to assess sets of variables.

Results

There were 31 910 medical records that met criteria. The frequency of SARS-CoV-2 positive tests was calculated in groups of HIV TP, FP, and PN. In total, 31 575 patients had PN HIV test result, 248 patients had TP, and 87 patients had FP. Those with HIV FP tests had the highest percentage of COVID-19–positive test results at 19.5%, which was significantly higher than HIV PN (11.3%; P = .016) and HIV TP (7.7%; P = .002). After adjustment for all covariates, only FP HIV was significantly associated with COVID-19 (odds ratio, 4.22; P = .001).

Conclusions

This study reveals that patients with positive SARS-CoV-2 PCR tests are significantly more likely to have an FP fourth-generation HIV test than those with negative SARS-CoV-2 PCR tests.
Are infrared thermography, feeding behavior, and heart rate variability measures capable of characterizing group-housed sow social hierarchies?
Authors: Sommer Dominique M , Young Jennifer M , Sun Xin , López-Martínez Giancarlo , Byrd Christopher J
Published: May 2023

Group gestation housing is quickly becoming standard practice in commercial swine production. However, poor performance and welfare in group housed sows may result from the formation and maintenance of the social hierarchy within the pen. In the future, the ability to quickly characterize the social hierarchy via precision technologies could be beneficial to producers for identifying animals at risk of poor welfare outcomes. Therefore, the objective of this study was to investigate the use of infrared thermography (IRT), automated electronic sow feeding systems, and heart rate monitors as potential technologies for detecting the social hierarchy within five groups of sows. Behavioral data collection occurred for 12 h after introducing five sow groups (1–5; n = 14, 12, 15, 15, and 17, respectively) to group gestation housing to determine the social hierarchy and allocate individual sows to 1 of 4 rank quartiles (RQ 1–4). Sows within RQ1 were ranked highest while RQ4 sows were ranked lowest within the hierarchy. Infrared thermal images were taken behind the neck at the base of the ear of each sow on days 3, 15, 30, 45, 60, 75, 90, and 105 of the experiment. Two electronic sow feeders tracked feeding behavior throughout the gestation period. Heart rate monitors were worn by 10 randomly selected sows per repetition for 1 h prior to and 4 h after reintroduction to group gestation housing to collect heart rate variability (HRV). No differences were found between RQ for any IRT characteristic. Sows within RQ3 and RQ4 had the greatest number of visits to the electronic sow feeders overall (P < 0.04) but spent shorter time per visit in feeders (P < 0.05) than RQ1 and RQ2 sows. There was an interaction of RQ with hour for feed offered (P = 0.0003), with differences between RQ occurring in hour 0, 1, 2, and 8. Higher-ranked sows (RQ1 and RQ2) occupied the feeder for longer during the first hour than lower ranking sows (RQ3 and RQ4; P < 0.04), while RQ3 sows occupied the feeder longer than RQ1 sows during hour 6, 7, and 8 (P < 0.02). Heart beat interval (RR) collected prior to group housing introduction differed between RQ (P = 0.04), with RQ3 sows exhibiting lower RR compared to RQ2 sows (P = 0.009). Overall, these results indicate that feeding behavior and HRV measures may be capable of characterizing social hierarchy in a group housing system.
Ewe early gestation supplementation with eicosapentaenoic and docosahexaenoic acids affects the liver, muscle, and adipose tissue fatty acid profile and liver mRNA expression in the offspring
Authors: Roque-Jiménez José A , Oviedo-Ojeda Mario F , Whalin Megan , Lee-Rangel Héctor A , Relling Alejandro E
Published: May 2023

Our objectives were to assess the effects of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) supplementation to pregnant ewes during the first third of gestation on their offspring’s liver, adipose, and muscle tissues fatty acid (FA) profile and liver mRNA expression after a finishing period receiving diets with different FA profiles. Twenty-four post-weaning lambs, blocked by sex and body weight, were used in a 2 × 2 factorial arrangement of treatments. The first factor was dam supplementation (DS) in the first third of gestation with 1.61% of Ca salts of palm fatty acid distillate (PFAD) or Ca salts enriched with EPA-DHA. Ewes were exposed to rams with marking paint harnesses during the breeding. Ewes started DS at the day of mating, considered day 1 of conception. Twenty-eight days after mating, ultrasonography was used to confirm pregnancy, and nonpregnant ewes were removed from the groups. After weaning, the offspring lambs were supplemented (LS, second main factor) with two different FA sources (1.48% of PFAD or 1.48% of EPA-DHA) during the growing and fattening phase. Lambs were fed the LS diet for 56 d and sent to slaughter, where the liver, muscle, and adipose tissue samples were collected for FA analysis. Liver samples were collected for relative mRNA expression for genes associated with FA transport and metabolism. The data were analyzed as a mixed model in SAS (9.4). In the liver, the amount of C20:5 and C22:6 (P < 0.01) increased in lambs with LS-EPA-DHA, while some C18:1 cis FA isomers were greater in the lambs from DS-PFAD. In muscle, amounts of C22:1, C20:5, and C22:5 increased (P < 0.05) in lambs born from DS-EPA-DHA. The adipose tissue amounts of C20:5, C22:5, and C22:6 were greater (P < 0.01) in lambs from LS-EPA-DHA. Interactions (DS × LS; P < 0.05) were observed for DNMT3β, FABP-1, FABP-5, SCD, and SREBP-1; having greater mRNA expression in liver tissue of LS-EPA-DHA, DS-PFAD and LS-PFAD, DS-EPA-DHA lambs compared with the lambs in the other two treatments. Liver ELOVL2 mRNA relative expression (P < 0.03) was greater in the offspring of DS-PFAD. Relative mRNA expression (P < 0.05) of GLUT1, IGF-1, LPL, and PPARγ increased in the liver from LS-EPA-DHA lambs. Dam supplementation during early gestation using with different FA sources changed the lipid FA profile in MT, LT, and SAT during the finishing period depending on the tissue and type of FA source administered during the growing phase.