bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Analysis of Different Machine Learning Algorithms for Identifying and Classifying the Failures of Traction Motors
Authors: Xian Xiaoyu , Tang Haichuan , Tian Yin , Liu Qi , Fan Yuming
Published: November 2021

This paper addresses electric motor fault diagnosis using supervised machine learning classification. A total of 15 distinct fault types are classified and multilabel strategies are used to classify concurrent faults. we explored, developed, and compared the performance of different types of binary (fault/non-fault), multi-class (fault type) and multi-label (single fault versus combination fault) classifiers. To evaluate the effectiveness of fault identification and classification, we used different supervised machine learning methods, including Random forest classification, support vector machine and neural network classification. Through experiment, we compared these methods over 4 classification regimes and finally summarize the most suitable machine learning algorithms for different aspects of health diagnosis in traction motors area.
Error Analysis of Cycloid Gear Based on Ellipse Fitting Based on Least Square Approach
Authors: Lou Sai , Liu Fucong , Wang Haoran
Published: November 2021

In this paper, under the condition of the existing processing and detecting technology, we used coordinate measuring machine (CMM) to measure the contour of cycloid gear. In order to improve the accuracy of measured data, we used Euclidean distance and Laida criterion to preprocess measured data. After preprocessing the measured data of the cycloid gear, we used ellipse fitting based on least square approach to fit the contour data points of the cycloid gear, and used the determination coefficient method to evaluate the goodness of fitting. According to the result of the curve fitting of cycloid gear, we used Matlab to analyse and calculate the pitch errors of cycloid gear, which provides data for the subsequent matching of parts combination of the best RV reducer with genetic algorithm.
Research and Optimization Design of Mixing Characteristics of High-speed Centrifugal Mixer Based on DEM
Authors: Li Hongjun , Zhou Xiao , Li Xu , Chen Wei , Zuo Ying
Published: November 2021

Aiming at the special production process of an environmental protection building material, a new mixing equipment, high-speed centrifugal mixer, was designed. In this paper, the mixing characteristics of high-speed centrifugal mixer were studied by using discrete element method (DEM). By constructing the contact model and establishing the evaluation system, the mixing process was simulated and analyzed by EDEM software, and the mixing situation of the two raw materials in the centrifugal mixer was obtained. At the same time, according to the two important factors affecting the mixing results, the comparative experimental analysis was carried out under different conditions, and finally the optimization suggestions for the equipment were put forward.
The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China
Authors: Jiang Jile , Wu Kun , Guo Bin , Wu Shi , Zhang Zhimin
Published: November 2021

A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.
A Depth Map Generation Method for Path Planning of Mobile Robot
Authors: He Qiang , Yu Jiawei
Published: November 2021

Recently, the unmanned mobile robots have received broad applications, such as industrial and security inspection, disinfection and epidemic prevention, warehousing logistics, agricultural picking, etc. In order to drive autonomously from departure to destination, an unmanned mobile robot mounts different sensors to collect information around it and further understand its surrounding environment based on the perceptions. Here we proposed a method to generate high-resolution depth map for given sparse LiDAR point cloud. Our method fits the point cloud into a 3D curve and projects LiDAR data onto the curve surface, and then we make appropriate interpolations of the curve and finally implement the Delaunay triangulation algorithm to all the data points on the 3D curve. The experimental results show that our approach can effectively improve the resolution of depth maps from sparse LiDAR measurements.
Experimental Study on Automatic Switching of Solar Coupled Groundwater Source Heat Pump System
Authors: Zhang Xiaoming , Wang Qiang , Sun Qiujin , Shao Mingyu
Published: November 2021

There have been few practical applications of solar coupled groundwater source heat pump (GWHP) systems in large public buildings, and data on this technology are scarce. A solar coupled GWHP system was investigated in this study. The system uses an underground water source heat pump system for heating in winter, cooling in summer, and providing part of the domestic hot water, and it also uses a solar energy system to prepare domestic hot water. These two types of energy are complementary. The system was tested throughout the cooling season. This experiment ran from May 10, 2021, to September 10, 2021. The results show that the system can guarantee the indoor design temperature and the supply of domestic hot water. The solar water heating system operated for 1233 min in the summer; hot water (2334 m3) was prepared. During the summer, the average energy efficiency ratio of the GWHP unit was approximately 4.88. The energy efficiency ratio of the entire system was approximately 3.34. Such projects can play a key role in demonstrating this type of system.
The Analysis and Compensation of Elastic Unbalance Torque of the Three-axis Air-bearing Simulator
Authors: Li Zhanxin , Cao Zizhen , Duan Wenjie , Du Yikang , Liu Haiteng
Published: November 2021

The most important interfering torque of a three-axis air-bearing simulator is the displacement of the center of mass in the gravity field caused by structural elasticity. In order to characterize the torque, a mathematical model of the interference moment was established. Based on the model, it is suggested that the vertical stiffness and horizontal stiffness of the structure should be equal as far as possible during the structural design, and the elastic unbalance moment can be compensated by the vertical offset of the center of mass of the air floating platform relative to the rotation center after the initial attitude leveling. ABAQUS was used to build a simulation model of the air floating platform, and the changes of the structure’s centroid before and after the gravitational field was applied were extracted by software to simulate the centroid deviation caused by the elastic deformation of the structure, which was used as the characterization to conduct discrete optimization of the structure. The optimal structural parameters were obtained. Then the disturbance torque curve and the corresponding initial centroid offset after initial centroid compensation were calculated by mathematical model. The results are of positive guiding significance to the design of three-axis air-bearing simulator.
Research on Evaluation Technology of Low Temperature Cold Start Performance of Hydraulic Oil
Authors: Chen Jinmao , Xu Lei , Zhang Chunlin , Wang Mengyi , Xiong Chunhua , Nie Yao
Published: November 2021

In order to comprehensively test the low temperature cold start performance of hydraulic oil and ensure their use effectiveness to the fullest, the idea of low temperature cold start performance index is proposed, so as to comprehensively evaluate the low temperature capability. Firstly, the cold start performance index system of hydraulic oil tested in low temperature environment is constructed, so as to describe its low temperature capability from multiple angles and in a comprehensive manner; secondly, for different index types, the corresponding data collection methods and data analysis methods are clarified, and the low temperature cold start performance of hydraulic fluid is evaluated. Finally, using the method as an example for three oils, the index types and assessment results are given to further illustrate the scientific nature of the research method. The research content can provide some technical support for the evaluation of the low temperature cold starting performance test of hydraulic winches.
A Simple Solution to the Cylindrical Indentation of an Elastic Compressible Thin Layer Resting on a Rigid Substrate
Authors: Wang ZQ , Dan ZL , Wu J
Published: November 2021

In this paper, an analytical model is presented to study the contact that recedes between an elastic thin film that could be compressed and a substrate of rigidity. The surface of rigidity was formed due to cylindrical indentation. The substrate was assumed to be a rough surface without any friction. Further, the contact width of the substrate was derived, and the relationship between the compression force, compression depth, and the compression width was determined using the energy method. Finally, the obtained results were validated using finite element analysis.
Thermal Decomposition and Kinetics of Cast Plastic Bonded Explosives Based on NTO and HMX
Authors: Kou Xinyu , Jin Shaohua , Chen Yu
Published: November 2021

In this work, we studied the influence of the ratio of NTO and HMX on the thermal decomposition performance of the series of cast PBXs. DSC was used to study the nonisothermal thermal decomposition performance of different PBXs, and ARC was used to study the adiabatic thermal decomposition. Both DSC and ARC results show that among the five different PBXs, N30 is the cast PBX with the best thermal stability.
Potential impacts of concurrent and recurrent climate extremes on the global food system by 2030
Authors: Chatzopoulos Thomas , Pérez Domínguez Ignacio , Toreti Andrea , Adenäuer Marcel , Zampieri Matteo
Published: November 2021

The risk of food-supply instability is expected to increase along with the frequency and intensity of extreme agro-climatic events in many regions. Assessing the sensitivity of the global agricultural system to evolving extremes requires the probability of occurrence of such events to be estimated and their links with potential food supply and demand culminations to be established. From this perspective, in this article we implement a novel approach that can be used as a tool to inform decision-makers about the resilience of agricultural markets to climate extremes. By incorporating simulated climate-stress events into a partial-equilibrium model of interconnected agricultural commodity markets, we examine the complex manifestations of grain supply, demand and prices attributable to hazardous extremes. Market outcomes are further synthesized into coherently defined vulnerability and risk indicators. The proposed framework currently covers compound heat and water anomalies at the country level, potentially concurrent and recurrent, that impact annual crop yields and market balances in a recursive-dynamic manner until 2030. Our findings indicate that extreme-climate anomalies significantly distort expected market equilibria in the medium term. Moreover, extreme global prices may result either from climate anomalies in single key countries or from simultaneous events in many regions. Last but not least, trade and storage come forth as important alleviative mechanisms of the market uncertainty provoked by recurrent extremes.
Alternative methods of verifying the reconstructed outline of a non-standard spur gear
Authors: Konecki K , Pytliński R , Kołodziej A , Domek G
Published: November 2021

Common methods of checking a gear that have been designed in reverse engineering are, for example, measurement with a modular caliper or disc micrometer. However, although these methods are among the most accurate, they allow only one or a few of the selected geometric parameters to be measured. The paper presents alternative methods of verification of the reconstructed outline of a very non-standard involute gear with the parameters m = 4.98, α = 26.325 °, x = 0.0695, y = 0.795, c* = 0.383. These methods are less accurate than the classic ones, but they allow for a comprehensive check of the entire outline of the reconstructed tooth. They are often used in industrial practice. However, here, in addition to the methodology, a short tolerance analysis was also carried out, which may to some extent compensate for the aforementioned measurement inaccuracy. The method consists in using the potential of a spreadsheet and CAD technique to generate an involute outline of a gear tooth whose geometry is recreated.
Assessment of the suitability of a gate design modification compared to the change in pressing velocity considering the distribution of gases in the casting volume
Authors: Majernik J , Tupaj M , Trytek A , Podařil M
Published: November 2021

The qualitative properties of high pressure die castings are closely correlated with their internal structure, which is directly conditioned by the gas entrapment in the melt volume during the casting cycle. It is known that the gas entrapment in the volume of the melt and their subsequent distribution into the cast can be reduced by changing the technological parameters of the casting cycle or by the modification of the gating system design. The contribution addresses the issue of which variant of the gas content reduction is more efficient regarding the gas entrapment and the nature of the melt flow in the runners. The experiments are based on a real casting process. The established design solution of the gating system and the technological parameters setting are considered as a referential. Different gating system modifications were designed where the design modification is connected with the cross-section of a gate, in which the final acceleration of the melt flow occurs. The observed melt velocity in the gate is considered as a correlation factor, based on which the modification in the piston velocity is determined. The assessed parameter is the gas entrapment in the cast volume at the end of the filling phase. Assessment of the casting cycle and evaluation of experiments is performed using simulation program Magmasoft. Based on the performed analyses, it can be stated that the gate design modification will affect the filling regime of the die cavity by changing the melt velocity in gate, but the nature of the melt flow in runners remains unchanged. Modification of the piston velocity affects the filling regime of the die cavity, and also the nature of the melt flow as it passes through the runners, thereby promoting the gas entrapment in the melt volume. Therefore, it is necessary to pay an increased attention to the design of the gating system and only after debugging the design to proceed to the optimization of technological parameters.
Virtual reality in Industry
Authors: Klačková I , Kuric I , Zajačko I , Tlach V , Wiecek D
Published: November 2021

The article deals with the issue and overview of the current trends in the field of virtual reality usage in various sectors. The main aim of contribution is an overview of virtual reality and its key components and tools nowadays, especially in areas such as engineering, automotive industry, civil administration, health care and entertainment industry. There are described the basic tools, applications and functions of virtual reality and its interaction with human operator. The main attention is paid to the use of virtual reality in the engineering industry and its division.
Preliminary analysis of the sensitivity of the FEM model of the process of dry ice extrusion in the die with a circularly converging channel on the changing its geometrical parameters
Authors: Górecki J
Published: November 2021

The article presents the results of a preliminary analysis of the numerical model susceptibility for simulating the process of dry ice compaction utilizing single-channel and multiple channel dies. The work focuses on a preliminary comparison of the influence of changes in the geometrical parameters of the 4 types of compression channels. Based on the results of the performed analyses, conclusions were formulated for a basis and direction of further study regarding improving the energy efficiency of the indicated manufacturing process.
Modeling of Mechanical Properties of the Polymeric Composite Reinforced with Braided Preform
Authors: Kondratiev A , Andrieiev O , Tsaritsynskyi A , Nabokina T
Published: November 2021

Braided composite structures based on preforms are widely used in various industries. Owing to use of such preforms high speed and efficiency of the process of manufacturing of polymeric composite materials and structures on their basis can be provided. Knowledge of their properties in the design allows optimizing the production of structures with the specified parameters. The paper gives the review of three approaches to the description of physical and mechanical characteristics of the composite with braided fixtures – based on the classical theory of layered media, rod-based model, and the method of polynomial approximation. The necessary estimated dependencies were derived in order to predict the elastic and structural behavior of the composites under study at any reinforcement angle according to the known characteristics of predetermined angles. Synthesized design parameters, as distinct from the existing ones, allow predicting strength characteristics of the composite based on the braided hoses depending on the positioning and location of the material on the shape-generating surface. For the verification of theoretical results, a number of experimental studies have been carried out with the formation of samples of the material with the different reinforcing angles. Comparison of the analytical and experimental results allows drawing the conclusions that rod-based model gives the best results for the description of elastic behavior of the polymeric composite materials, whereas the obtained polynomial dependences are recommended for the structural behavior. The results of the work represent the basis for solving the problems of calculation of strength of the structures made of composite materials based on the braided preforms
Simulation modelling of material handling using AGV
Authors: Dobrzanska M , Dobrzanski P
Published: November 2021

Modern production systems are mainly characterized by, among others, the use of automated transport systems. One of the components of such transport systems are automated guided vehicles (AGV). These vehicles are primarily used in the material handling due to their greater efficiency, flexibility and lower operating costs. The main aim of the article is to present the possibility of using simulation modelling in the analysis of internal transport operations using automated guided vehicles.
Possibility of using Matlab application to propose fuzzy computer model
Authors: Hrehova S , Husár J , Hladký V
Published: November 2021

More and more organizations in various fields apply the principles of the Industry 4.0 philosophy. The result, among other benefits, is the acquisition of a large amount of data. Data can be of great importance to them in terms of decision support, analysis and, last but not least, as a resource for simulations and computer models. Currently, various approaches and software applications can be used to create models. One of the applications that allows the creation of computer models in various fields is Matlab. Diversity of use is ensured by different sets of tools, which are specifically focused on individual areas and thus provide the necessary tools. In the presented paper we focus on the possibilities of using fuzzy approach in the design of a computer model in the field of heating with the tools of the Fuzzy Logic Controller toolbox. The basis for creating the model will be historical data obtained from the real object. The individual tools of the toolbox, the creation and presentation of rules will be described, as well as the connection of the proposed model with the Simulink environment.
Mechanical properties of ductile cast iron relation to the charge elements
Authors: Pacha-Gołębiowska H , Piekarska W
Published: November 2021

In many recent publications on the optimisation of alloys in terms of, among other things, their strength and resistance to wear, a trend can be observed to look for new alloying additives to improve these properties. This paper presents the results of a study on the effect of changes in the chemical composition of EN-GJS-500-7 ductile alloy cast iron on its mechanical properties. In order to confirm the effect of alloying additives on the mechanical properties of the alloys, industrial melting of cast iron was carried out and samples were taken for testing. The smelts were not subjected to heat treatment, but were carried out differently in terms of the feedstock used and based on the analysis of the cooling curve using an automated smelting technology enabling the elimination of degraded Chunky graphite. The influence of the shape of graphite precipitates on tensile strength and hardness was determined, and spectroscopic studies of the microstructure of cast irons were carried out.
Technic solutions analysis and development of the innovation design protective elements of railway tank wagons
Authors: Kravchenko K , Šťastniak P , Harušinec J , Gerlici J , Moravčík M
Published: November 2021

The absence of protective elements on railway tank wagons in case of accidents can lead to significant losses and adverse effects on the environment. This is especially the case for railway wagons for transportation of ignition matters. The article deals with the analysis and the development of the protective elements structures. Two variants of protection are developed - anti-climbing devices and protective shields. Innovation patented design variants are presented. New materials are used in protective constructions, such as aramid, non-Newtonian fluid. A series of measurements and simulation analyses for the integration of protective elements have been made. For the selected constructions, the results of strength researches of constructions are presented. The advantages of the proposed designs are evaluated.
Contribution to the analysis of grinder vibrations using condition monitoring procedures based on vibration measurements
Authors: Dekýš V , Čilíková M , Gavlas M , Novák P , Sapietová A , Pástor M
Published: November 2021

The article deals with the vibration of the workpiece on the grinder using a cBN grinding wheel. The workpieces were made of hardened steel with a hardness of 62 HRC and ceramics: Al2O3, SiC, Si3N4, and ZrO2/Y2O3. Grinding was performed at different infeed rates during 5 consecutive passes. Up and down grinding were also evaluated. Measured realizations of the acceleration of the workpiece during grinding were processed in the time and frequency domain and compared with each other. We consider acceleration patterns to be diagnostic signals that will help to understand the process of chip formation during grinding as well as the process of damaging parts made of the tested materials.
Composite Materials with Epoxy Matrix and Their Properties
Authors: Skalková P , Krmelová V , Krmela J , Ondrušová D , Crkoň A , Benčiková E
Published: November 2021

This work was focused on studying the properties of epoxy (EP) composite materials reinforced with glass, (GF) carbon (CF) and aramid (AF) fibres. The composites were made by hand lay-up (HL) and vacuum infusion process (VIP) with 8, 10, 12 number of fabric layers. Studied were tensile strength, elongation, flexural stress, flexural strain, thermal stability, texture of surfaces, cuts, fractures of laminates and the thickness of the laminate according to the type and number of layers of fabric and the method of manufacture. Composites made by VIP achieve better mechanical properties than composites made by HL. Tensile strength was highest in composites reinforced with AF. Composite materials reinforced with GF exhibit the lowest values of tensile strength. Flexural strength was significantly the highest in CF reinforced composites followed by the laminates reinforced with GF and AF. The highest values of flexural deformation were measured in composites reinforced with AF and the lowest values of flexural deformation were measured in composites reinforced with CF. By thermogravimetric analysis (TG) was recorded weight loss of the EP matrix in the range from 290 to 480 °C and AF in range from 530 to 605 °C. By TG was demonstrated lower content of EP matrix in the composites made by VIP, which was confirmed by comparison of thickness of the studied laminates.
Kinematic and dynamic analysis and distribution of stress for six-item mechanism by means of the SolidWorks program
Authors: Vavro J , Vavro J , Marček L , Taraba M , Klimek L
Published: November 2021

This paper presents a kinematic and dynamic analysis and distribution of the stress for six-item planar mechanism by means of the SolidWorks software. The main purpose of the investigation is connected with the kinematic analysis of planar mechanisms as well as with the implementation of the vector method into the SolidWorks software program in order to determine the kinematic variables of the individual bodies in the whole investigated system. The process of the dynamic analysis is based on the kinematic analysis. The dynamic analysis makes possible to design a system of bodies correctly and it is with the respect to the dynamic loading. For the interpretation of the introduced analysis, the six-item planar mechanism was used as example (representative). Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on time. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is great solution to use SolidWorks software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modeling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.
Influence of design features of a multi-edge shredder on the operational characteristics of the process of comminution corn stalks
Authors: Łączny D , Macko M , Moraczewski K , Lewandowski J
Published: November 2021

The paper presents a comparative analysis of the effect of selected design features of blade and disc units on the functional characteristics of the process of grinding corn stalks in specific ranges of input variables. The effect of changes in the geometric features of the working units and rotational speeds on the energy demand during the grinding process was estimated. On this basis, an assessment of the quality of the shredding product in terms of shape and size was also made.
Results verification of numerical simulation of the side impact of a vehicle in a three-point bending test
Authors: Evin E , Nemeth S
Published: November 2021

The research objective was to use numerical simulation to verify safety characteristics of deformation zone reinforcements subjected to bending, obtained from experimental results of the stretch-bending test. The methodology proposed for result verification by means of numerical simulation using a three-point bending test was verified on a sheet metal strip made of micro alloyed steel H 220 PD and a two-phase ferritic-martensitic steel DP 600. Material data for the material model according to Krupkovsky were determined in the tensile test. The measured data were processed tabularly and graphically. A comparison of the deformation work constant and the stiffness and deformation force constants shows that a very good match between the measured and the calculated characteristics has been achieved. Based on the data obtained, it can be assumed that it is possible to reduce the weight of deformation elements while maintaining the required safety characteristics by replacing micro alloyed steel H 220PD with the two-phase DP steel.
Method of Modelling a Tank with Ribbing using a Spatial Scanner for Optimized Control of Volume Characteristics
Authors: Krenicky T , Straka L
Published: November 2021

Increasing requirements for product quality, whether from the side of technical standards or customers, generate demands on the optimization of measurement and data evaluation processes, which include also dimensional characteristics. The paper deals with determining the volume of the tank of a railway wagon with ribbing. In practice, volume flow meters are usually used to measure the internal volumes of manufactured tanks, which measure the volume of water when filled with water. The method is not only time-consuming but also energy-consuming and generates a large amount of wastewater. Therefore, these obsolete methods are gradually being replaced by those that allow effective inspection of tank wagon dimensions according to the technical documentation. The topic of the paper is a description and verification of the design of a progressive method of determining the internal volume of the tank using a spatial 3D scanner Faro FocusS150 and software processing of measured data. At the same time, verification of compliance with the requirements for the accuracy of determining the internal volume of the tank is presented. The aforementioned methods are therefore compared in terms of accuracy, complexity and time consumption.
Modeling the longitudinal dynamics of electric multiple units with Xcos/Scilab software
Authors: Jackiewicz J
Published: November 2021

During the traction and braking of trains, substantial longitudinal dynamic forces might occur in couplers. The method of modeling these forces for two different electric multiple units (EMUs) is presented in this study. For the EMUs consisted of independent vehicles, each of which rests on two bogies, computer simulations were carried out. Simulations were also executed for EMUs with Jacobs bogies, which support bodies of two adjacent carriages. The dynamic modeling of vibration protection train systems includes nonlinearities.
Production injection moulds with additive technology by the HP MJF 4200 printer
Authors: Chval Z , Raz K , Stepanek M
Published: November 2021

This paper is focused on the production plastic parts. It is describing two technologies-injection moulding and additive technology. The production process of the metal mould for the new parts takes about ten weeks. It is necessary to make some reductions after the mould is produced. It is increasing the time which is necessary for the prototype of products. This time (from the initial design of mould to the prototype of product) can take about six months. Additive technologies can be used for decreasing this time and for cost reduction. Moulds produced by the additive technology are mostly special inserts which can be implemented in the universal design of mould. It is also possible to produce whole moulds from plastic material. These moulds can have integrated cooling channels. There are high demands on the material of the mould with respect to the thermal resistivity, toughness and surface quality. There are really often used SLA technologies, which are considering the High Temp Resin and Material Jetting Digital ABS. Other options used in the factories are Somos PerFORM and Digital ABS Plus. This paper deals with the possibility of usage of the HP Jet Fusion technology with the material PA12 GB for the production of mould inserts and it is evaluating this process and repeatability of process.
The method of measuring motion capture in wheelchairs during actual use – description of the method and model of measuring signal processing
Authors: Wieczorek B , Kukla M
Published: November 2021

The aim of the article is to verify the method of measuring motion capture in wheelchair during conditions of actual use and to formally describe how the measurement points are processed. The developed method and the measurement data processing process extract a set of parameters from the study that describe the kinematics of the human body while propelling a wheelchair. The method includes an algorithm to process data from video recorded with a sports camera to the coordinates of the marker position. For the selected marker positions, a data processing algorithm was proposed to determine universal parameters used in the assessment of the kinematics of the human body in terms of wheelchair use. The method has been verified with actual tests that analyzed the kinematics of the human body while propelling a wheelchair under various operating conditions. The proposed method of measuring motion capture involves inexpensive research equipment, offers the possibility of use in real conditions.
Overview of the possibilities of surface modification of materials using energy beam technologies
Authors: Balint Bali R , Zajac J , Botko F , Botková D
Published: November 2021

Along with new trends, the manufacturing industry is also forced to move forward. Therefore, we focused on the use of Waterjet Peening technology - WJP. With the help of this technology, we can strengthen the material (harden) and remove residual stresses. This technology uses high pressure of water jet. Parameters also play an important role, namely the distance of the nozzle from the material being machined, the working pressure is standing, the feed rate, the number of cycles, etc. WJP technology is also promising from an ecological point of view, no harmful substances are formed during machining. Studies have also shown that, there are no heat affected zones during machining. When comparing the mentioned technology on samples made of surgical steel and titanium alloy, it was shown that the sample made of surgical steel showed greater signs of corrosion traces. Based on an experimental comparison of WJP technology and shot blasting technology, it is shown that the technologies achieved relatively the same results in terms of residual stress removal. A significant difference was found on the surface of the material, in the form of the degree of surface damage. With the help of WJP technology, the material did not reach such a roughness level as after shot blasting technology.
Topology optimization of the tool holder produced with additive manufacturing
Authors: Stepanek M , Raz K , Chval Z
Published: November 2021

This paper deals with the topology optimizations of tool holder where three different mass targets were required. The holder was loaded with 499 N. Weight reduction of the tool holder placed in tool turret can positively affect the bearing durability. Easier manipulation with the holder is one of the results. In the process of the topological optimization manufacturing constraints, such as overhang prevention, self-supporting and material spreading were defined for needs of Direct Metal Laser Sintering production technology. Structural analyses of three obtained geometries were simulated for evaluation of the stiffness in three main directions of the tool holder. Finally, the weight and the stiffness of each individual geometry was compared and prepared for manufacturing.
Simulation of manipulation task using iRVision aided robot control in Fanuc RoboGuide software
Authors: Bulej V , Bartoš M , Tlach V , Bohušík M , Wiecek D
Published: November 2021

The article deals with simulation of visual guided robot (VGR) in offline programming software Fanuc RoboGuide. At the beginning there is a brief description of the Fanuc RoboGuide system. The practical part contains an example of the task where the configuration and demonstration of offline programming of visual guided robot system via industrial camera is presented. The main aim of the work is to practically verify the functionality of the system usable for intelligent handling and assembly workplaces.
Improving mechanical properties of the UIC test bench
Authors: Čajkovič L , Pribilinec F
Published: November 2021

Brakes are one of the most important components of vehicles. This is due to their function of decelerating, regulating vehicle speed and keeping vehicles stationary. The correct function and reliability of this system is essential for safe operation and vehicles driving.

In our case, we deal with the brakes of rail vehicles. As trainsets achieve higher weights and speeds, great emphasis is also placed on improving the friction components of brake systems, which must meet the strict parameters set by the International Union of Railways (UIC) and must be tested on specialized approved test benches, before being put into service. As the demands on the development of friction components increase, so do the demands on their testing. From this point of view, there is necessary constant improvement in the measuring lane of the brake bench. It is necessary to improve the measuring and control technology as well as the mechanical components.

This paper deals with the study of mechanical components in terms of operational dynamics. The main idea of the work is to create a virtual model of the brake bench in order to simulate the operating states and determine the critical modes with a possible adverse impact on the course of measurement and control. During the measurement, the monitored parameter is an important simulated mass, which must meet a precisely determined tolerance for the success of the measurement.
Issues related to an attempt to recreate the geometry of a non-standard spur gear
Authors: Konecki K , Wojtkowiak D , Talaśka K , Kołodziej A , Domek G
Published: November 2021

Modern machine manufacturers are making the design and technology of their products more and more complicated. This is to protect against a frequently used practice at customers, i.e. making extra parts on your own. This is because entrepreneurs often cannot afford to order expensive original spare parts and - using reverse engineering - prepare working drawings and commission the components to be made in their own machine park or externally from local suppliers. However, the matter is more complex in the case of gears, which so far have been designed on the basis of the selection of standard geometric parameters. A small modification of one or more of these parameters is enough and it becomes very difficult to recreate the geometry of such a gear. This paper presents the issues related to the reverse engineering of a spur involute gear with very non-standard parameters m = 4.98, α = 26.325 °, x = 0.0695, y = 0.795, c* = 0.383. Further metrological steps were proposed that should be taken to correctly identify at least the fact that the test object is not a part produced by standard modular tools (Fellows cutter, Maag rack cutter, worm cutter, etc.). The work also includes short graphical analyzes of the recreated geometry.
𝐶*-algebras and their nuclear dimension
Authors: Castillejos Jorge
Published: November 2021

We review the notion of nuclear dimension forC∗\mathrm {C}^*-algebras introduced by Winter and Zacharias. We explain why it is a non-commutative version of topological dimension. After presenting several examples, we give a brief overview of the state of the art.
A survey on the blow-up method for fast-slow systems
Authors: Jardón-Kojakhmetov Hildeberto , Kuehn Christian
Published: November 2021

In this document we review a geometric technique, called the blow-up method, as it has been used to analyze and understand the dynamics of fast-slow systems around non-hyperbolic points. The blow-up method, having its origins in algebraic geometry, was introduced to the study of fast-slow systems in the seminal work by Dumortier and Roussarie in 1996, whose aim was to give a geometric approach and interpretation of canards in the van der Pol oscillator. Following Dumortier and Roussarie, many efforts have been performed to expand the capabilities of the method and to use it in a wide range of scenarios. Our goal is to present in a concise and compact form those results that, based on the blow-up method, are now the foundation of the geometric theory of fast-slow systems with non-hyperbolic singularities. Due to their great importance in the theory of fast-slow systems, we cover fold points as one of the main topics. Furthermore, we also present several other singularities such as Hopf, pitchfork, transcritical, cusp, and Bogdanov-Takens, in which the blow-up method has been proved to be extremely useful. Finally, we survey further directions as well as examples of specific applied models, where the blow-up method has been used successfully.
On fractional higher-order Dirichlet boundary value problems: Between the Laplacian and the bilaplacian
Authors: Saldaña Alberto
Published: November 2021

The solutions of boundary value problems for the Laplacian and the bilaplacian exhibit very different qualitative behaviors. Particularly, the failure of general maximum principles for the bilaplacian implies that solutions of higher-order problems are less rigid and more complex. One way to better understand this transition is to study the intermediate Dirichlet problem in terms of fractional Laplacians. This survey aims to be an introduction to this type of problems; in particular, the different pointwise notions for these operators is introduced considering a suitable natural extension of the Dirichlet boundary conditions for the fractional setting. Solutions are obtained variationally and, in the case of the ball, via explicit kernels. The validity of maximum principles for these intermediate problems is also discussed as well as the limiting behavior of solutions when approaching the Laplacian or the bilaplacian case.
A Cross-Sectional Decision-Making Approach to Inform Neuropsychological Battery Development in Professional Hockey
Authors: Bruce Jared M , Meeuwisse Willem , Thelen Joan , Hutchison Michael G , Comper Paul , Echemendia Ruben J
Published: November 2021

Objective

Neuropsychologists commonly use a large battery of tests to inform clinical decisions. Decision analysis can be used to determine which individual tests play a role in the decision-making process. The objective of this project was to conduct quantitative and qualitative decision analysis of decisions by team neuropsychologists with professional hockey players being evaluated as part of the National Hockey League (NHL)/NHL Players Association Concussion Protocol.

Method

We extracted neuropsychological data from an NHL clinical program database. Team neuropsychologists evaluated concussed players using a hybrid neuropsychological test battery. The neuropsychologists then determined whether players were experiencing concussion-related cognitive difficulties. Logistic regression was used to examine which tests accounted for unique variance in the decision-making process. We also conducted a survey of NHL neuropsychologists, asking them to rate the usefulness of each test in the battery.

Results

Five of the fifteen measures accounted for unique variance in team neuropsychologists’ decisions, including the ImPACT Verbal Memory Composite, Visual Motor Composite, Reaction Time Composite, Symptom Score, and Brief Visuospatial Memory Test—Revised Delayed Recall. Notable discrepancies were uncovered between quantitative indications of usefulness and self-reported qualitative perceptions of test usefulness when making decisions. Qualitatively, clinicians reported that the Hopkins Verbal Learning Test—Revised, Symbol Digit Modalities Test, ImPACT Reaction Time, and Color Trails 2 were the most useful tests when making decisions.

Conclusions

Along with validation studies, decision analysis can be used as part of a comprehensive evaluation process to inform the development of best-practice batteries for use among athletes with sports concussion.
Computational modeling of mRNA degradation dynamics using deep neural networks
Authors: Yaish Ofir , Orenstein Yaron
Published: November 2021

Motivation

messenger RNA (mRNA) degradation plays critical roles in post-transcriptional gene regulation. A major component of mRNA degradation is determined by 3′-UTR elements. Hence, researchers are interested in studying mRNA dynamics as a function of 3′-UTR elements. A recent study measured the mRNA degradation dynamics of tens of thousands of 3′-UTR sequences using a massively parallel reporter assay. However, the computational approach used to model mRNA degradation was based on a simplifying assumption of a linear degradation rate. Consequently, the underlying mechanism of 3′-UTR elements is still not fully understood.

Results

Here, we developed deep neural networks to predict mRNA degradation dynamics and interpreted the networks to identify regulatory elements in the 3′-UTR and their positional effect. Given an input of a 110 nt-long 3′-UTR sequence and an initial mRNA level, the model predicts mRNA levels of eight consecutive time points. Our deep neural networks significantly improved prediction performance of mRNA degradation dynamics compared with extant methods for the task. Moreover, we demonstrated that models predicting the dynamics of two identical 3′-UTR sequences, differing by their poly(A) tail, performed better than single-task models. On the interpretability front, by using Integrated Gradients, our convolutional neural networks (CNNs) models identified known and novel cis-regulatory sequence elements of mRNA degradation. By applying a novel systematic evaluation of model interpretability, we demonstrated that the recurrent neural network models are inferior to the CNN models in terms of interpretability and that random initialization ensemble improves both prediction and interoperability performance. Moreover, using a mutagenesis analysis, we newly discovered the positional effect of various 3′-UTR elements.

Availability and implementation

All the code developed through this study is available at github.com/OrensteinLab/DeepUTR/.

Supplementary information

Supplementary data are available at Bioinformatics online.
The Effects of Flower Patch Density on Pollinator Visitation
Authors: Barley Tristan A , Martinez Algarin Michael G , Bauer Jonathan T
Published: November 2021

There is conflicting research regarding how conspecific plant density can affect pollinator visitation, with some studies indicating dense flower patches will receive more visitors and other studies demonstrating the opposite. This study investigated the effects of conspecific density on pollinator visitation in a restored prairie. Three plant species, Penstemon digitalis (Nutt. ex Sims) (Lamiales: Plantaginaceae), Monarda fistulosa (L.) (Lamiales: Lamiaceae), and Eryngium yuccifolium (Michx.) (Apiales: Apiaceae), were observed, with visiting pollinators recorded. Conspecific density did not have an effect on total pollinator visitation rates for any of the focal plant species. However, different groups of pollinators varied in their responses to flower density, notably with larger Bombus spp. tending to visit dense flowering patches more than did other groups of bees. This suggests that plant density may impact certain pollinators differently than others. These results also indicate a possible mechanism through which multiple pollinator species can coexist while only one flowering resource is available, with the foraging behavior of smaller bees potentially allowing them to avoid competition with larger, social bees. Furthermore, a comparison of seed weight demonstrated that E. yuccifolium plants tended to have larger seed sets in isolated individuals, suggesting that flowers in large patches may be pollinated less effectively and are competing for, rather than facilitating, pollinator visits.