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• Commercial-of-the shelf (COTS) space qualified solenoid valves for small satellite missions are financially unviable. • Thrusters control spacecraft attitude, the response time, and parameters of the solenoid valve is critical in mission design. • A mathematical model was developed to find the optimized geometrical configuration of the solenoid valve. • This paper presents a practical solution for designing custom solenoid valves. • The developed mathematical model validated using COTS space qualified solenoid valves. Small satellites and spacecrafts use propulsion systems to stabilize their attitude, control orientation and deorbit it at the end of the mission life. The flow and thrust of the liquid propulsion system are controlled by the control valve, typically operated by solenoid. According to recent literature, space-qualified solenoid valves are expensive and financially non viable, especially for small satellite missions. In this paper, a detailed methodology is presented to design the solenoid valve dedicated for small satellites. This study includes design criteria focusing on geometrical configuration. The dynamic, and electro-magnetic models are used to characterize the solenoid valve. Dynamic modelling helps to determine the response time of valve, affecting the thruster minimum impulse bit. The physical dimensions of the designed solenoid valve are smaller than those available in commercial off-the shelf (COTS) solenoid valves. However, the efficacy of the proposed design is proven effective with the COTS space grade valve specifications, and it shows that the proposed valve consumes less power than the conventional valves. Finally, it is worth noting that despite their modest and compact physical dimensions, the proposed valve are ideal for small satellite missions. [ABSTRACT FROM AUTHOR]

Considering the problems that quantitative analysis and optimization of the geometrical model of scroll compressor created from involute of circle with variable radii are incomplete, the changing trend of the working chamber volume from the beginning of the suction process to the end of the discharge process is given. The volume calculation differences of Green’s theorem method, the graphical method, and the normal isometric method are compared, the reasons for calculation errors are analyzed, and the correctness of the geometrical model is verified. The calculation formula of teeth area utilization rate is deduced, and the sensitivity models of suction volume and teeth area utilization rate are constructed. It is concluded that the influence of the base circle radius variation coefficient and the occurrence angle of the inner profile are particularly significant. A multi-objective optimization analysis model considering nonlinear constraints and taking the suction volume and teeth area utilization rate as the optimization goals is established. The results show that the multi-objective genetic algorithm NSGA-II has a better comprehensive performance than the multi-objective particle swarm algorithm MOPSO and the suction volume of the scroll compressor created from the involute of circle with variable radii for an automobile air conditioner has been increased by 6.5% and the teeth area utilization rate has been reduced by 4.27%. This paper can provide further theoretical reference for the optimal design and quantitative research of the scroll compressor constructed from involute of circle with variable radii.

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To improve the dimensional stability of weft knitted fabrics, spandex yarns are incorporated with the base yarn by the plaiting technique. Adding spandex leads to stitch overlapping, increases the fabric thickness, and affects the pore’s size and distribution. This in turn affects the geometrical and physical properties of weft knitted fabrics such as air permeability. In this paper, the theoretical 3D modeling of stitch overlap, maximum set, and open structures is presented by using AutoCAD software. Fabric thickness was divided into several sections, and the theoretical porosity at each section was analyzed and calculated. Furthermore, single jersey knitted fabrics SJKF with and without spandex were produced to obtain overlapping (by using spandex weight percent, SWP 8%), and open structures. The calculated and theoretical overall porosity were calculated and compared. The study showed the influence of stitch overlapping on fabric porosity. Moreover, the results show that the proposed model captured to some extent the change in fabric porosity as its structure changes.

To improve the dimensional stability of weft knitted fabrics, spandex yarns are incorporated with the base yarn by the plaiting technique. Adding spandex leads to stitch overlapping, increases the fabric thickness, and affects the pore’s size and distribution. This in turn affects the geometrical and physical properties of weft knitted fabrics such as air permeability. In this paper, the theoretical 3D modeling of stitch overlap, maximum set, and open structures is presented by using AutoCAD software. Fabric thickness was divided into several sections, and the theoretical porosity at each section was analyzed and calculated. Furthermore, single jersey knitted fabrics SJKF with and without spandex were produced to obtain overlapping (by using spandex weight percent, SWP 8%), and open structures. The calculated and theoretical overall porosity were calculated and compared. The study showed the influence of stitch overlapping on fabric porosity. Moreover, the results show that the proposed model captured to some extent the change in fabric porosity as its structure changes. [ABSTRACT FROM AUTHOR]

Currently sensing devices have relatively single functions, complex structures, high prices, and are not easily portable. In this context, this paper innovatively applies the self-sensing of superelastic SMA wires to the field of planar displacements and forces sensing, developing a new type of multi-functional sensing unit. The sensing unit is composed of only two frames and eight wires, which can realize multiple sensing functions. This paper presents a resistance regression prediction model suitable for different temperatures based on the phase transition dynamics of superelastic shape memory alloy. In the working process of the sensing unit, according to the resistance regression prediction, the stress and strain can be obtained by resistance. Then the translational and rotational displacements, forces and torque of the measured object can be obtained using the geometrical and mechanical solution methods proposed in this paper. Finally, this paper constructs the sensing unit sample and verification experimental platform, and comprehensively discussed the reliability of the sensing unit at different temperatures. The sensing unit, compared to traditional sensing devices, has advantages such as small size, simple structure, low cost, and integrated functionality, making it an innovative exploration in the application direction of superelastic shape memory alloy. [Display omitted] • A multi-functional sensing unit is proposed with only eight superelastic SMA wires. • The sensing unit can obtain planar 3DOFs displacements and force simultaneously. • Geometrical and mechanical solution methods are proposed for the sensing unit. • A resistance regression model based on SMA phase transition behavior is proposed. • Feasibility and accuracy of the sensing unit is verified by experimental platform. [ABSTRACT FROM AUTHOR]

ObjectiveA-T flap has been extensively applied to repair dermal soft tissue defects. The flap design completely depends on the experience of doctors. Herein, we explored the approach of analyzing the reasonability of A-T flap design and performed a simulation of operation processes by computer-aided technology. Afterward, the finite element analysis software (MSC.Marc/Mentat) was used to establish the simulation model, based on which the computer simulation of flap suturing and release state in A-T flap surgery was performed.MethodsA geometrical model of the A-T flap was established, and the length-width ratio of the flap, maximum suture distance, and suture area that could influence the postoperative suture effects of the flap were analyzed. The reasonable surgical planning for A-T flap design based on the crossing constraint relationship was achieved. The simulation model was established by the finite element analysis software (MSC.Marc/Mentat), based on which computer simulation of flap suture and release state of A-T flap in surgery processes were performed. The flap’s stress and deformation distribution results confirmed the applicability of the A-T flap design method proposed in the present study.ResultsWhen the apex angle of the A-T flap was 60 degrees, the suture area was the smallest, and the flap design had the highest practicability.ConclusionComputer-assisted preoperative assessment, which has high clinical value, could provide a theoretical basis for A-T flap design in clinical practice.

This paper addresses the problem of automatic quality inspection in assembly processes by discussing the design of a computer vision system realized by means of a heterogeneous multiprocessor system-on-chip. Such an approach was applied to a real catalytic converter assembly process, to detect planar, translational, and rotational shifts of the flanges welded on the central body. The manufacturing line imposed tight time and room constraints. The image processing method and the features extraction algorithm, based on a specific geometrical model, are described and validated. The algorithm was developed to be highly modular, thus suitable to be implemented by adopting a hardware–software co-design strategy. The most timing consuming computational steps were identified and then implemented by dedicated hardware accelerators. The entire system was implemented on a Xilinx Zynq heterogeneous system-on-chip by using a hardware–software (HW–SW) co-design approach. The system is able to detect planar and rotational shifts of welded flanges, with respect to the ideal positions, with a maximum error lower than one millimeter and one sexagesimal degree, respectively. Remarkably, the proposed HW–SW approach achieves a 23× speed-up compared to the pure software solution running on the Zynq embedded processing system. Therefore, it allows an in-line automatic quality inspection to be performed without affecting the production time of the existing manufacturing process. [ABSTRACT FROM AUTHOR]

The image vectorization based on geometrical contour representation is an active research topic. It involves approximating the contour of the objects inside the image using geometrical definition or estimation. Typical approach of estimating the parameters of the geometrical model is fitting-based estimation. However, the noise that exists in the image causes degradation in the performance. In order to overcome this degradation, we propose integrating evolutionary based optimization. In this article, the design of the operators of the genetic optimization for improving the contour detection results of segments-based estimation of the contour is proposed. The operator includes both crossover and mutation. The evaluation shows that Structural Similarity Index Metrics (SSIM) measure has increased after applying it from 0.64 to 0.77 on UEC Food 100 Dataset and from 0.54 to 0.66 after applying it to UEC Food 256 Dataset. [ABSTRACT FROM AUTHOR]

The notion of negative numbers is one of the most fundamental in mathematics. For many years, they have caused confusion and they have been an object of controversy among great researchers, until the development of symbolic algebra led to their acceptance in the form they have today. When students are first introduced to the concept of negative numbers and the operations between them, various difficulties occur and misconceptions arise, as expected. Their comprehension is one of the most challenging tasks of teaching mathematics due to their complexity and abstract nature. For this purpose, various models have been devised and employed. In the present study we expose some of the epistemological obstacles commonly observed in understanding negative numbers and then exhibit and compare two different models frequently used for introducing the four basic operations between them.

Information about the assembly process is directly influenced to the product accuracy. A modeling technique based on the schematization of the assembly process information for predict the product accuracy is proposed. Information about assembly deviations is displayed by the geometry deviations in contact points, the propagation of deviations between parts and the direction of deviations propagation. A schematic connection is established between the assembly process information and the deviations propagation information, a technique for precision assembly modeling include a method based on adapting the mathematical apparatus used in the kinematics of robots and a methodology for influencing of assembly deviations transitions.

Abstract Tubular Braided Composites (TBC) have a higher strength to weight ratio than conventional materials and better mechanical properties compared to laminated composite materials. The optimization of the TBC and the introduction of new applications requires a comprehensive understanding of TBC’s behavior. One efficient way to study the behavior of TBC is using Finite Element Modeling (FEM). This paper will introduce a method for generating geometrical models with different patterns and variables. Micro Computed-Tomography ( μ CT) is also used for generating an actual 3-D model of a TBC. The geometrical model and the μ CT models are visually compared. The geometrical model is inputted into the FEM software package and is studied in different conditions. Finally, the result of FEM is compared against experimental and analytical results. [ABSTRACT FROM AUTHOR]

The cylinder profile primarily determines the working performance of the sliding vane compressor. In order to increase the built-in volume ratio and compression ratio of the compressor, in this study, a novel asymmetrical cylinder profile composed of an exponential spiral was proposed, and then a novel asymmetrical sliding vane compressor was obtained. A geometric model of the proposed asymmetrical cylinder profile was established, and effects of power exponent n on the built-in volume ratio, area utilization ratio and acceleration of the cylinder profile were discussed. Furthermore, the working process of the proposed sliding vane compressor were simulated using structured dynamic grids, distributions of flow fields in the working chambers were obtained, and the gas pressure varying with the rotational angle was also analyzed. The study results show that the proposed sliding vane compressor has many remarkable advantages, small discharge volume, large built-in volume ratio and large compression ratio, compared with the traditional sliding vane compressor with the symmetrical cylinder of a circle profile under the same geometric size. The contents of this study are of great significance for promoting the development and application of sliding vane compressors. [ABSTRACT FROM AUTHOR]

Joints are the weakest links in the composite pipes under internal pressure due to the discontinuity of reinforcement in connection area. Weft-knitted integrated preforms can be used to enhance the strength of these composite joints. The focus of this study is to develop a geometrical model for the finite element analysis of composite joints reinforced with single jersey weft knitted fabric, which take cylindrical forms. Thus our efforts are concentrated on generating geometrical models for weft-knitted integrated preforms as reinforcement of Tee-joint, and various Wye-joint composites in pipelines. A geometrical model was first developed for loops on the curved surfaces by modifying the offered model for loops on flat surfaces. Then, the joint was divided into two cylinders; main cylinder and joint. Each cylinder was modeled using the generated model for loops on curved surfaces. The modeled cylinders were assembled according to the structure of joints. A python algorithm was proposed to simulate the weft-knitted integrated preforms in Abaqus/CAE 2016 commercial package. By implementing the proposed algorithm, the geometry of reinforcement was modeled for three types of joints based on technical data of ASME-B31. To verify the generated model, T-shape weft knitted integrated preform was produced using glass yarn count of 220 tex, CPC and WPC of 6 and 4, respectively. Comparing the experiment and simulation results shows a maximum error percentage of 10 % in the predicting the structural parameters of joints. It can be concluded that the generated model can well predict the geometry of weft-knitted preforms. [ABSTRACT FROM AUTHOR]

The implementation of control systems in metal forming processes improves product quality and productivity. By controlling workpiece properties during the process, beneficial effects caused by forming can be exploited and integrated in the product design. The overall goal of this investigation is to produce tailored tubular parts with a defined locally graded microstructure by means of reverse flow forming. For this purpose, the proposed system aims to control both the desired geometry of the workpiece and additionally the formation of strain-induced α′-martensite content in the metastable austenitic stainless steel AISI 304 L. The paper introduces an overall control scheme, a geometry model for describing the process and changes in the dimensions of the workpiece, as well as a material model for the process-induced formation of martensite, providing equations based on empirical data. Moreover, measurement systems providing a closed feedback loop are presented, including a novel softsensor for in-situ measurements of the martensite content.

• A spherical surface geometrical model that generates RCM motion is presented. • A novel family of generalized single-loop RCM-PMs are synthesized. • A general kinematic model is established to analyze the presented RCM-PMs. • The presented RCM-PM possesses analytical kinematics solutions and good workspace. In this paper, a novel family of generalized single-loop remote center of motion (RCM) parallel mechanisms (PMs) based on a spherical surface geometric model is proposed. The underlying principles behind generating RCM motion are intuitively revealed through geometry. The spherical surface geometric models are first constructed through the application of the midperpendicular theorem of chords by utilizing basic geometric elements (point, line, and surface). A general arrangement of generalized single-loop remote center of motion parallel mechanisms (RCM-PMs) is then established by combining the geometric models with the single-loop structure. The construction principle of generalized single-loop RCM-PMs is subsequently derived. By means of the construction principle, a family of generalized single-loop RCM-PMs are synthesized. Additionally, a general kinematic model is established to analyse this family of generalized single-loop RCM-PMs. Finally, a case study is implemented, including the kinematics and performances analysis, and the simulation of a generalized single-loop RCM-PM. The proposed generalized single-loop RCM-PMs possess several advantages, such as a modular structural design, a good drive unit, analytical kinematics solutions, no internal singular configurations, and a large workspace. [ABSTRACT FROM AUTHOR]

István Lampé,1 Dezső Beke,2 Sándor Biri,3 István Csarnovics,4 Attila Csik,3 Zsuzsanna Dombrádi,5 Péter Hajdu,3 Viktória Hegedűs,6 Richárd Rácz,3 István Varga,7 Csaba Hegedűs11Department of Biomaterials and Prosthetic Dentistry, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary; 2Department of Solid State Physics, University of Debrecen, Debrecen, Hungary; 3Hungarian Academy of Sciences, Institute for Nuclear Research, Debrecen, Hungary; 4Department of Experimental Physics, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary; 5Department of Medical Microbiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; 6Department of Orthodontics, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary; 7Department of Periodontology, Faculty of Dentistry, University of Debrecen, Debrecen, HungaryObjectives: Using dental Ti implants has become a well-accepted and used method for replacing missing dentition. It has become evident that in many cases peri-implant inflammation develops. The objective was to create and evaluate the antibacterial effect of silver nanoparticle (Ag-NP) coated Ti surfaces that can help to prevent such processes if applied on the surface of dental implants.Methods: Annealing I, Ag ion implantation by the beam of an Electron Cyclotron Resonance Ion Source (ECRIS), Ag Physical Vapor Deposition (PVD), Annealing II procedures were used, respectively, to create a safely anchored Ag-NP layer on 1x1 cm2, Grade 2 titanium samples. The antibacterial effect was evaluated by culturing Staphylococcus aureus (ATCC 29213) on the surfaces of the samples for 8 hours, and comparing the results to that of glass as control and of pure titanium samples. Alamar Blue assay was carried out to check cytotoxicity.Results: It was proved that silver nanoparticles were present on the treated surfaces. The average diameter of the particles was 58 nm, with a 25 nm deviation and Gaussian distribution, the the filling factor was 25%. Antibacterial evaluation revealed that the nanoparticle covered samples had an antibacterial effect of 64.6% that was statistically significant. Tests also proved that the nanoparticles are safely anchored to the titanium surface and are not cytotoxic.Conclusion: Creating a silver nanoparticle layer can be an option to add antibacterial features to the implant surface and to help in the prevention of peri-implant inflammatory processes. Recent studies demonstrated that silver nanoparticles can induce pathology in mammal cells, thus safe fixation of the particles is essential to prevent them from getting into the circulation.Keywords: implants, peri-implant inflammation, oxyde layer, cytocompatibility, antibacterial effect, physical vapor deposition, geometrical model

Recently, a novel technology for noninvasive deep brain stimulation (NDBS) with temporally interfering electric fields was developed. This noninvasive technology is able to perform one-point temporal interference (TI) stimulation and stimulates the hippocampus without affecting the overlying cortex in mice. In this study, we introduce the concept of multi-point temporal interference (MTI) stimulation, which can simultaneously stimulate multiple nodes in the brain network to modulate its function. For the sake of realizing MTI stimulation, we proposed the scheme with each electrode carrying different frequency currents, which has higher usability with respect to the scheme by adding more electrode pairs. Additionally, to optimize the MTI stimulation, we selected the proper current frequencies and amplitudes, which were verified by geometrical model, magnetic resonance imaging (MRI) human head model, and tissue phantom. Finally, we tested the independence between the two stimulation points in MTI stimulation. The MTI stimulation can be generated by our method with proper parameters in geometrical model, MRI human head model, and tissue phantom. The stimulation points in MTI stimulation are all steerable, and furthermore can be controlled independently. Our results suggest that MTI stimulation can be used to simultaneously stimulate multiple target nodes of the brain network in deep brain areas noninvasively, which paves the way for the modulation of the brain in research and clinical neurobiology.

Featured Application: In our paper, we developed a new, geometrical structure-based approach and its graph theory-based geometric model with graph theory-based notation, which can be used in the future for city logistics system planning with cargo bikes. Nowadays, cargo bikes are seeing an ever-greater role in city logistics with an increasing number of deliveries, and it is essential to examine their future role in green and smart cities. In our work, we examine the application of cargo bikes in the city logistics system of the urban concentrated sets of delivery locations, focusing first on shopping malls, with the investigation of the geometrical structure of the logistics network. In the examined concept, the use of cargo bikes will be combined with electric trucks to make possible green deliveries of urban concentrated sets of delivery locations. In this paper, we present the experiences of the existing systems and the related research, the simulation model of the examined new concept with cargo bikes and its results, the graph theory-based geometric model of the examined city logistics system with graph theory-based notation, and the application of the new approach for Budapest. The main output of this research is the geometrical model of the urban concentrated sets of delivery locations and its application. Based on this geometrical model, it will be possible to decide about the suitability of the examined cargo bike-based city logistics concepts for given cities. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of automatic quality inspection in assembly processes by discussing the design of a computer vision system realized by means of a heterogeneous multiprocessor system-on-chip. Such an approach was applied to a real catalytic converter assembly process, to detect planar, translational, and rotational shifts of the flanges welded on the central body. The manufacturing line imposed tight time and room constraints. The image processing method and the features extraction algorithm, based on a specific geometrical model, are described and validated. The algorithm was developed to be highly modular, thus suitable to be implemented by adopting a hardware–software co-design strategy. The most timing consuming computational steps were identified and then implemented by dedicated hardware accelerators. The entire system was implemented on a Xilinx Zynq heterogeneous system-on-chip by using a hardware–software (HW–SW) co-design approach. The system is able to detect planar and rotational shifts of welded flanges, with respect to the ideal positions, with a maximum error lower than one millimeter and one sexagesimal degree, respectively. Remarkably, the proposed HW–SW approach achieves a 23× speed-up compared to the pure software solution running on the Zynq embedded processing system. Therefore, it allows an in-line automatic quality inspection to be performed without affecting the production time of the existing manufacturing process.

Vehicle-to-vehicle (V2V) wireless communications have many envisioned applications for ensuring traffic safety and for addressing traffic congestion. However, developing suitable communication systems and standards for this purpose requires developers to have accurate models for the V2V propagation channel. Likewise, the dynamic evolution of multipath components (MPCs) in V2V channels has not been well modeled in existing models. In this paper, we propose a geometry-based stochastic channel model for a lightly built-up urban environment and then parametrize the model from measurements. The MPCs are extracted based on a high-resolution parameter estimation; they are tracked and clustered through a joint algorithm. The identified clusters are classified as line-of-sight, reflections from static scatterers, reflections from mobile scatterers, multiple-bounce reflections, and diffuse scattering. Specifically, the multiple-bounce reflections are modeled as twin clusters that follow the COST 273/COST2100 approach. The paper gives a full parameterization of the channel model and supplies a step-by-step implementation recipe. We verify the model by comparing two second-order statistics, i.e., the root-mean-square (RMS) delay spread and the angular spreads of arrival/departure derived from the channel model, to the results obtained directly from the measurements. Furthermore, we also identify several key factors that strongly impact the synthetic channel performance. [ABSTRACT FROM AUTHOR]

Ferrite-based slags are the basic systems in the pyrometallurgical production of copper, and the density and molar volume of these systems are of vital importance for optimizing the metallurgical process. However, due to the high melting points of melts and the expensive trial costs, experimental methods are inefficient to obtain all the data needed. As a result, a geometrical model has been applied to the estimation of density and molar volume of ferrite-based ternary slags. The calculated results agree well with experimental data in three ferrite-based ternary systems of Fe 2 O 3 –CaO–FeO, Fe 2 O 3 –BaO–FeO and Fe 2 O 3 –CaO–Cu 2 O. The mean deviation of the predicted results by the present model is lower than those by various empirical models for corresponding systems. The application of the present will enrich the data of density and molar volume for more ternary melts. [ABSTRACT FROM AUTHOR]

Geometrical model is an important part of the CALPHAD method and has been widely used for the prediction of physicochemical properties of multicomponent systems. However, most of the researches are focused on the comparison of the predicted results by various geometrical models, and very few studies have analyzed the underlying causes of these differences. In this paper, we will discuss the factors affecting the predicted results of geometrical models by analyzing the whole calculation procedures. When the experimental data is constant, it is found that the predicted results are mainly affected by two factors, which can be concluded as the fitting order of Redlich-Kister equation and the selection rules of three representative points. The influences of the two factors are analyzed in the viscosity prediction of Au-Cu-Ag ternary system.

The original configuration of 3D layer-to-layer angle-interlock (LLA) woven fibers cannot be maintained during matrix impregnation and is unstable when the composite is subjected to loading. The fibers in the yarn are susceptible to lateral sliding, resulting in deformation of the textile geometry. The initial modulus of the composite in the warp direction is smaller and can be inconsistent owing to the unstable geometry of the fabric. A stable 3D layer-to-layer angle-interlock (SLLA) fabric was devised by constructing a denser yarn arrangement, and the properties of this new structure were investigated in this study. The geometric parameters of this novel reinforcing structure were mathematically modeled, and the results were validated experimentally. The results showed that the SLLA structure was more stable than that of the LLA fabric. The experimentally determined structural parameters were in good agreement with the theoretically calculated values.

Modeling the assembly process is an important stage in the development of the product and assembly of the model, which is basic in the analysis of properties and the design of the product. The purpose of this study is to obtain quantitative characteristics of the dimensional parameters of joint with reference to the coordinate system in modeling of the assembly process and subsequent visualization of geometrical models of details and their joints in the Excel program, by adapting the mathematical apparatus used in the kinematics of robots to solve problems of relevance in the modeling and analysis assembly process.

This work presents a geometrical model of coatings fabricated by powder-fed Directed Energy Deposition (DED) and defines guidelines and manufacturing strategies for multilayered structures based on the geometrical model results. This model obtains as output both the overlapped clad geometry and the dilution area of the coating at different input parameters and defines the strategy of multi-layer structures. The results of this work validate the model that comes in handy: a) To understand the influence of each parameter and the single clad geometry when fabricating coatings and structures; b) To select the parameters depending on the requirements of the coating like effective thickness and dilution; c) To detect lack of fusion with the substrate due to an excessive overlap percentage; d) To select the deposition strategy and the tool path for additive manufacturing; e) To select the subsequent machining strategy based on the predicted geometry of the model. [ABSTRACT FROM AUTHOR]

A geometrical model for lockstitch seam 301 has been proposed based on elliptical profile to estimate the thread consumption. The realistic elliptical shape of a lockstitch 301 seam has been confirmed by observing cut section along seam line. In order to validate a model across the different fabric types, varieties of fabrics from woven shirting, woven jeans, knitted single jersey to nonwoven interlining fabric have been considered. The different number of plies (2, 3 and 4) of given fabrics have been stitched at different levels of stitch densities (3, 4 and 5 stitches per cm) to observe effects in prediction of these parameters. It is found that the error % is increasing with increase in stitch density and number of ply. The proposed elliptical model have been compared with other recent rectangular profile based models, it is found that the propose model is more accurate and generalised with less error %, as compared to other models across the different fabric types. Also there is a strong correlation obtained between practical (actual) thread consumption and predicted from model. [ABSTRACT FROM AUTHOR]

A simple and flexible method for theoretical calculation of the main structural parameters of various weft-knitted fancy and combined patterns is presented in this article. It is especially important for patterns containing different elements, such as loops, floats of different lengths, tucks, and tuck stitches. Measurement of an actual average length of the loop in these fabrics is complicated because it is necessary to disassemble precisely one pattern repeat to measure the yarn length and divide it by the number of elements in this pattern repeat. For large and complex pattern repeats, this is difficult and usually gives a high number of errors. It is very important to have lengths of structural elements as it helps to predict the main physical properties of knitted fabrics and their mechanical behaviour, which is especially important for protective textiles. The main idea of the proposed method, based on Čiukas geometrical model, is to calculate lengths of various structural elements or even their parts separately, taking into account the number of needle bars and their formation principle, which gives great flexibility to such modelling. The proposed theoretical formulas can be used for various patterned weft-knitted structures containing not only loops but tucks, floats of different lengths, or additional yarns; they give very few errors in empirical calculations and are easy to use.

This study is focused on isothermal and anisothermal precipitation of M23C6 carbides from the fully ferritic structure of the (γ + δ) austenitic-ferritic duplex stainless steel X2CrNiMo2253, (2205). During isothermal heat treatments, small particles of K-M23C6 carbide precipitates at the δ/δ grain-boundaries. Their formation precedes γ and σ-phases, by acting as highly potential nucleation sites, confirming the undertaken TEM investigations. Furthermore, anisothermal heat treatment leads to the formation of very fine islands dispersed throughout the fully δ-ferritic matrix. TEM characterization of these islands reveals a particular eutectoid, reminiscent of the well-known (γ-σ)—eutectoid, usually encountered in this kind of steel. TEM and electron microdiffraction techniques were used to determine the crystal structure of the eutectoid constituents: γ-Austenite and K-M23C6 carbides. Based on this characterization, orientation relationships between the two latter phases and the ferritic matrix were derived: cube-on-cube, on one hand, between K-M23C6 and γ-Austenite and Kurdjumov-Sachs, on the other hand, between γ-Austenite and the δ-ferritic matrix. Based on these rational orientation relationships and using group theory (symmetry analysis), the morphology and the only one variant number of K-M23C6 in γ-Austenite have been elucidated and explained. Thermodynamic calculations, based on the commercial software ThermoCalq® (Thermo-Calc Software, Stockholm, Sweden), were carried out to explain the K-M23C6 precipitation and its effect on the other decomposition products of the ferritic matrix, namely γ-Austenite and σ-Sigma phase. For this purpose, the mole fraction evolution of K-M23C6 and σ-phase and the mass percent of all components entering in their composition, have been drawn. A geometrical model, based on the corrugated compact layers instead of lattice planes with the conservation of the site density at the interface plane, has been proposed to explain the transition δ-ferrite ⇒ {γ-Austenite ⇔ K-M23C6}.

Background: The aim of this study was to develop a nucleotide geometrical model of the circular mitochondrial DNA (mt-DNA) structure using Geant4-DNA toolkit to predict the radiation-induced damages such as single-strand breaks (SSB), double-strand breaks (DSB), and some other physical parameters. Methods: Our model covers the organization of a circular human mt genetic system. The current model includes all 16,659 base pairs of human mt-DNA. This new mt-DNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site-hit probabilities due to the impact of proton particles. The accuracy of the geometry was determined by three-dimensional visualization in various ring element numbers. The hit locations were determined with respect to a reference coordinate system, and the corresponding base pairs were stored in the ROOT output file. Results: The coordinate determination according to the algorithm was consistent with the expected results. The output results contain the information about the energy transfers in the backbone region of the DNA double helix. The output file was analyzed by root analyzing tools. Estimation of SSBs and DSBs yielded similar results with the increment of incident particle linear energy transfer. In addition, these values seem to be consistent with the corresponding experimental determinations. Conclusions: This model can be used in numerical simulations of mt-DNA radiation interactions to perform realistic evaluations of DNA-free radical reactions. This work will be extended to supercoiled conformation in the near future.

Serious security risks and economic losses have increased rapidly under the threat of foreign object debris. Most detection methods employing optical devices are limited in severe weather for low visibility. This study proposes an applicable approach for moving foreign object debris on the basis of space-time adaptive processing. The geometrical model of an airport is introduced whereby the runway and lawn are divided into clutter cells. After calculating the complex amplitude of clutter in each cell, the authors employ the minimum variance power spectrum and degrees of freedom to describe the ground clutter characteristics. Then the space-time filter is designed under the linearly constrained minimum variance criterion to suppress the clutter and detects the moving target. Simulations show that the errors in azimuth and Doppler are both less than −15 dB when SCNR = −20 dB.

Here, a multi-physics approach is presented for the design optimisation of an integrated modular motor drive (IMMD). The system is composed of a modular permanent magnet synchronous motor (PMSM) and a GaN-based modular motor drive power stage. The multi-physics model includes motor drive inverters and DC-link capacitor bank (electrical model), stator windings and rotor magnets (electromagnetic model), heat sink (thermal model), and a geometrical model. The main purpose of the design optimisation is to obtain the highest power density possible, which is quite critical in integrated drives. Due to the integrated structure, the system has several interdependencies and parameters are selected based on those relationships. An 8 kW IMMD system design is proposed from the developed optimisation tool and evaluated. The resultant system has a power density of 0.71 kW/lt, drive efficiency of 98.3%, and motor efficiency of 96.6%.

Nowadays, cargo bikes are seeing an ever-greater role in city logistics with an increasing number of deliveries, and it is essential to examine their future role in green and smart cities. In our work, we examine the application of cargo bikes in the city logistics system of the urban concentrated sets of delivery locations, focusing first on shopping malls, with the investigation of the geometrical structure of the logistics network. In the examined concept, the use of cargo bikes will be combined with electric trucks to make possible green deliveries of urban concentrated sets of delivery locations. In this paper, we present the experiences of the existing systems and the related research, the simulation model of the examined new concept with cargo bikes and its results, the graph theory-based geometric model of the examined city logistics system with graph theory-based notation, and the application of the new approach for Budapest. The main output of this research is the geometrical model of the urban concentrated sets of delivery locations and its application. Based on this geometrical model, it will be possible to decide about the suitability of the examined cargo bike-based city logistics concepts for given cities.

Serious security risks and economic losses have increased rapidly under the threat of foreign object debris. Most detection methods employing optical devices are limited in severe weather for low visibility. This study proposes an applicable approach for moving foreign object debris on the basis of space-time adaptive processing. The geometrical model of an airport is introduced whereby the runway and lawn are divided into clutter cells. After calculating the complex amplitude of clutter in each cell, the authors employ the minimum variance power spectrum and degrees of freedom to describe the ground clutter characteristics. Then the space-time filter is designed under the linearly constrained minimum variance criterion to suppress the clutter and detects the moving target. Simulations show that the errors in azimuth and Doppler are both less than −15 dB when SCNR = −20 dB. [ABSTRACT FROM AUTHOR]

Here, a multi-physics approach is presented for the design optimisation of an integrated modular motor drive (IMMD). The system is composed of a modular permanent magnet synchronous motor (PMSM) and a GaN-based modular motor drive power stage. The multi-physics model includes motor drive inverters and DC-link capacitor bank (electrical model), stator windings and rotor magnets (electromagnetic model), heat sink (thermal model), and a geometrical model. The main purpose of the design optimisation is to obtain the highest power density possible, which is quite critical in integrated drives. Due to the integrated structure, the system has several interdependencies and parameters are selected based on those relationships. An 8 kW IMMD system design is proposed from the developed optimisation tool and evaluated. The resultant system has a power density of 0.71 kW/lt, drive efficiency of 98.3%, and motor efficiency of 96.6%. [ABSTRACT FROM AUTHOR]

In this paper we define an equivalence relation on the set of all possible geo- metrical models of M(n, k) containing n points in 3D Euclidean space having k distinct distances. We investigate the number of geometrical models for M(4, 2), M(5, 2) and M(6, 2) up to the mentioned equivalence relation. [ABSTRACT FROM AUTHOR]

Warp knitted fabrics are mainly used as household goods, technical textiles, medical textiles, etc. Modeling of these fabrics is necessary for predicting the desired technical or medical functions beforehand. In this context, the present series of papers is devoted to the modeling of basic warp knitted fabrics. In this, Part II of this series, models for single guide bar fabrics are created. There are mainly two types of single bar fabrics, namely closed-lap and open-lap single bar fabrics. Structures are also changed by having different lapping movements up to the five needle spaces. In this work, 1 and 1, 2 and 1, 3 and 1, 4 and 1 closed-lap and 1 and 1, 2 and 1, 3 and 1 open-lap single bar warp knitted fabrics are considered. During modeling, the loop leanings in the course-wise direction are considered, curvature equalities at the loop parts are attained as much as possible, two connected parabolas are taken as the fabric plane model of the loop connection part, loop heads are taken as parametric ellipses in two dimensions and the remaining loop parts are modeled by wrapping parabolic or cubic curves on imaginary cylindrical or conical objects. The models created are versatile and they can be changed and used for special cases. The models created are drawn to scale by using the 3DS-MAX computer graphical program. At first glance, it is seen that the shapes obtained by the models are similar to the ones that can be observed in real samples. [ABSTRACT FROM AUTHOR]