Part Of Structure Research Articles

GYROID CELL USAGE IN TOPOLOGY OPTIMIZATION OF LOAD-CARRYING PARTS

This paper discusses the implementation and usage of a gyroid cell in topology optimization of load-carrying structural parts. Conventional topology optimization relies on a linear elastic model and the strain energy density field of the structure in order to optimally distribute the material within a given domain. This procedure may take place either on a completely unrestricted topological domain space or on a restricted preconfigured domain. The latter option is often chosen in order to enforce a cellular type structure of the part. In this context, surface-based cells like the gyroid cell may be an attractive option under special circumstances. For that reason, this paper addresses briefly the problem of numerical processing of the topological domain space in case of gyroid cell usage. In this context, a numerically efficient and stable procedure is proposed, suitable to be engaged on very large finite element meshes. Furthermore, an interesting numerical example demonstrates that conventional topology optimization of a linear model can even be used to tune the plastic dissipation of a structure under large deformations.

Study of critical deviation transfer for assembly of complex structural parts of aircraft

In current assembly process of the aircraft complex structural parts, there are problems such as nonlinear, multilevel strong coupling and large uncertainty transfer relationship between assembly quality and its deviation sources. In this paper, an assembly deviation transfer method based on transfer entropy network graph is proposed to address the challenges. Firstly, the source of assembly deviation is analysed by constructing a multi-level assembly coordination network with assembly deviation detection data. Secondly, an assembly deviation propagation model is established by combining transfer entropy and complex network graph theory. This model provides insights into the topological relationship of assembly deviations and introduces causal metrics for evaluation. The effectiveness of method is demonstrated through its application in the assembly of an aircraft nose, thereby verifying its practicality and utility.

Superplastic deformation behavior of low Al–added medium Mn steels with and without Ti and Mo elements

Fe-Mn-Al-C medium Mn steels were found to reveal extraordinary superplasticity and have significant potential for forming the complex structural parts due to high strength, excellent ductility and material cost. In present study, the effect of tensile deformation temperature on the superplastic deformation behavior of a cold-rolled low Al-added medium Mn steel was studied. A maximum tensile elongation of approximately 1170% was obtained at 745 °C and 10−2 s−1, which is to our best knowledge the highest low-temperature-high-strain-rate superplasticity in medium Mn steels. Also, the role mechanism of microalloying elements such as Ti and Mo was revealed to further enhance the strength level of superplastic medium Mn steels. In view of the representative microstructural features, such as equiaxed grains, random texture, and sluggish grain growth, grain boundary sliding is thought to be the dominative mechanism during the high-strain-rate superplastic deformation.

Dynamic Load Analysis of Mine-Truck Using Multibody Dynamic Analysis Method

Abstract: Vehicle load distributed on front & rear axle assembly during various working conditions is one of the most important factors influencing working performance and service life of drive axle assembly. The dynamic load on axle assembly is higher compared to the rated load because of variations in vehicle speed and road surface conditions. Early failure of structural components is caused because of higher dynamic reaction forces due to uneven road profiles. The dynamic load calculation of axle assembly is presented in this paper for a Mine-truck with various road conditions and vehicle speeds. The road load conditions consist of grade, bump & path hole. Mine-truck with payload capacities of 63 Ton is considered for the study. The behaviour of vertical force is calculated for different vehicle speeds (3 - 12 km/hr.) of the machine on the front & rear axle assembly during running conditions. Multi-body dynamic Analysis tool ADAMS is used for this study. ADAMS helps to study the dynamics of moving parts and load distribution throughout mechanical systems during motion. The Mine-truck3D model was created with the help of computer-aided design (CAD) software. Major units of Mine trucks are considered to prepare 3D models like Cabin-engine mass, Bucket, front axle assembly, rear Axle assembly & tires. Multi-body vehicle models are prepared in simulation software ADAMS by importing 3D models prepared by computer-aided design (CAD) software. This provides guidelines for selecting dynamic load factors while designing structural parts of the vehicle.

Improving awareness of foreign domestic workers during the COVID-19 pandemic using infographics: An experience during the crisis

The COVID-19 epidemic is a significant humanitarian crisis witnessed in contemporary times, necessitating the exploration of techniques and approaches that might augment the capabilities of individuals within society to mitigate the adverse consequences of this pandemic. Domestic workers have always been an important part of societal structure, and it is essential to ensure their awareness about the perils of the pandemic as well as implement preventive measures. This is crucial in order to effectively address the hazards associated with the ongoing epidemic. The primary objective of this study was to assess the efficacy of infographic technology in augmenting the level of knowledge among foreign domestic workers on the COVID-19 epidemic. The present study employed a quasi-experimental design to examine and compare the effects of infographic technology on the experimental group, while the control group received only public awareness messages disseminated to all citizens and residents. The study sample comprised (16) foreign domestic workers, who were assigned to the two research groups through a random allocation process. The development of the COVID-19 pandemic awareness scale was conducted. The measurement scale consisted of three dimensions: the cognitive awareness dimension, including a set of (12) statements; the performative awareness dimension, comprising a set of (8) statements; and the psychological awareness dimension, comprising a set of (10) statements. The findings demonstrated the superiority of the experimental group, which used the infographic approach, over the control group in fostering awareness of the COVID-19 epidemic throughout its three dimensions among the participants of the study. The study suggested the need of expanding the utilization of infographics in an attempt to enhance knowledge and awareness of the COVID-19 pandemic, alongside the establishment of varied databases for migrant domestic workers. The objective is also to develop an extensive digital awareness strategy about the impacts of the COVID-19 epidemic, so as to include an increased number of informative infographics.

Peran Pertanian dalam Pengembangan Ekonomi: Penilaian Transformasi Struktural dan Dinamika Pertumbuhan Ekonomi

By understanding the role of agriculture in economic development holistically, this research aims to provide policy makers, practitioners, and academics with deeper insights on how to enhance the role and contribution of the agricultural sector in achieving inclusive and sustainable economic growth. Through a careful evaluation of the structural transformation and dynamics of economic growth in the agricultural sector, this research is expected to provide valuable guidance in formulating more effective and future-oriented policies. In this study, the use of qualitative methods involved a variety of techniques and approaches. By using these qualitative methods, the research was able to explore various complex aspects of how agriculture plays a role in economic development, including the challenges, opportunities, social dynamics, and policies that affect it. Research results The agricultural sector is an important part of a country's economic structure, involving a wide range of activities from production to distribution of agricultural products. While agriculture is often the dominant sector in the early stages of economic development, its role continues to change as the economy develops. The role of the agricultural sector is crucial in feeding the population, creating jobs, and contributing to economic growth, especially in developing countries. However, agricultural activities can also have significant impacts on the environment, such as land degradation and ecosystem damage.

Comprehensive analysis of fused deposition modeling process conditions for enhancing mechanical properties and surface quality of 3D-Printed poly-ether-ether-ketone

Fused deposition modeling (FDM) technology is a convenient manufacturing approach for poly-ether-ether-ketone (PEEK) components. In this study, a comprehensive study of the influence of FDM process parameters on the mechanical property and surface quality of 3D-printed PEEK printed with different directions was carried out. The results show that crystallinity of PEEK materials and the pores/gaps between the printing filaments jointly affect the mechanical properties and surface quality of PEEK structural parts. Then, material-structure-property linkage mechanism was revealed. Through the research conducted, crucial processing parameters to enhance the mechanical properties and surface quality of PEEK samples was determined. High tensile strength (91.75 MPa, which was close to the performance of injection molded components) and surface quality (Ra 7.9 μm) was obtained by regulation the nozzle temperature and annealing temperature to improve the crystallinity. Meanwhile, tensile strength of z-Sample was increased from 7.36 MPa to 18.30 MPa (with an increase of 148.64%). High Young's modulus (3.09 GPa) and large plastic strain (exceed 13.91%) was achieved by regulation the nozzle temperature and printing speed to reduce the porosity between PEEK filaments.

Investigating the interplay of genetic variations, MCP-1 polymorphism, and docking with phytochemical inhibitors for combatting dengue virus pathogenicity through in silico analysis

Abstract Understanding ten significant of dengue virus a paramount due to its persistent threat across the globe causing numerous epidemic and millions of deaths every year. Despite advancement in healthcare, emerging outbreaks continue to claim millions of lives annually. The virus with its various serotype possesses a significant challenge to public health worldwide, its transmission through the arthropods which feed on the blood of higher animals further exacerbates its impact. This elucidating the mechanism and factor contributing to dengue virus pathogenicity is essential for developing strategies to combat its spreading. A systemic review is done while studying about Dengue virus serotypes to evaluate the relationship of dengue with other viral load and to develop an inhibitor in viral protein by using different bioinformatics tools in silico molecular docking. Phytochemicals were chosen to hit the target site of protein for inhibiting its active site in pathogenesis of Dengue virus. A phylogenetic lineage was observed of virus with other members of its family. Dengue virus has same similarities in some part of genomic structure with other viruses. Data bases were used to trace the genome of the virus. Different components of virus were analyzed and link was developed among those components within virus and other family members. Protein docking was performed by using the bioinformatics software auto docking. A pharmaceutical drug designing was developed to create inhibitor of protein structure in Dengue virus serotype-2. A comprehensive review of the methodology employed in our study including the experimental and computational techniques were utilized. Further we presented the results by analysis of genetic variation MCP-1 polymorphism and docking phytochemical inhibitors.

The Future of Island City Development From The Perspective of Geographical Science

Island cities are an important part of modern urban structure, playing an important role in the economic development of coastal countries. In recent years, with population growth and the need for socio-economic development, island urban development has been given top priority to create a suitable living and working environment for residents. At the same time, it protects the marine environment and ensures national security and defense. Besides the benefits that island urban development brings, there are negative impacts on island resources and the environment due to massive urban development. In particular, in a context where the world increasingly faces challenges of climate change, environmental pollution, and economic competition, sustainable island urban development is urgent. From a comprehensive perspective of geographical science based on synthesizing research documents on island urban areas, this article clarifies the future trend of island urban development, which requires attention to the unique characteristics of islands, if you want to develop sustainable island urban areas in the future, you need to follow the philosophy "Relying on Nature - Suitable for land - Harmony of people".

Non-parametric Regression Among Factor Scores: Motivation and Diagnostics for Nonlinear Structural Equation Models.

We provide a framework for motivating and diagnosing the functional form in the structural part of nonlinear or linear structural equation models when the measurement model is a correctly specified linear confirmatory factor model. A mathematical population-based analysis provides asymptotic identification results for conditional expectations of a coordinate of an endogenous latent variable given exogenous and possibly other endogenous latent variables, and theoretically well-founded estimates of this conditional expectation are suggested. Simulation studies show that these estimators behave well compared to presently available alternatives. Practically, we recommend the estimator using Bartlett factor scores as input to classical non-parametric regression methods.

Development and Application of an FSI Model for Floating VAWT by Coupling CFD and FEA

The emerging floating vertical axis wind turbines (VAWTs) are regarded as a preferred solution to overcome the challenges faced by the traditional horizontal type in open-sea environments. Numerous numerical models have been advanced for assessing this novel object. However, current fully coupled models predominantly rely on simplified theories, assuming a linear fluid load and a one-dimensional slender beam structure. Despite computational fluid dynamic and finite element (CFD-FEA) coupling being qualified for high precision, this technology remains limited to the fixed VAWT field. To predict the load and structural response accurately and comprehensively, this study aims to extend CFD-FEA technology to floating VAWTs. First, an aero-hydro-moor-elastic fully coupled model is developed, and this model is validated by comparing it with several model experiments. Subsequently, a full-scale floating straight-bladed VAWT is simulated with the geometry and numerical models introduced. Furthermore, load and structural responses in a typical case are analyzed in both time and frequency domains. Finally, the sensitivity analysis of each structure part in floating VAWTs to environmental parameters is conducted and discussed. The discovery highlights the intricate nature of tower structural response, which incorporates 2-node, 3-node, wind frequency, and wave frequency components. Distinct from blades or floating foundations, which are primarily influenced by a single environmental parameter, the tower response is significantly amplified by the combined effects of wind and waves.

Forecasting the trend of specialized digital marketing of social media in Iran

This article examines the role of social media as a powerful factor in marketing and its impact on organizational structure with a special focus on digital marketing. It outlines the components and roadmap for integrating digital marketing into social media. This research used customers who used the services and products of Internet businesses. 384 people were randomly selected The research questionnaire has been given to them. After providing them with the questionnaire, the analysis of the information obtained from the implementation of the questionnaires has been done using the method of structural equation modeling and with the help of PLS software in two parts the measurement model and the structural part. The results showed that social networks have a positive and meaningful role in the development of digital marketing of Internet businesses. It was also found that social networks can play an effective role in digital marketing website development, digital marketing search engine optimization development, digital marketing click-based advertising development, digital marketing online public relations development, and digital marketing email marketing development

МОДЕРНІЗАЦІЯ СТРУМОПРИЙМАЛЬНОЇ ГОЛОВКИ ТРОЛЕЙБУСА

The article deals with the issue of improving the reliability of the existing fleet of passenger trolleybuses. One of the possible options for increasing the reliability of operation of the trolleybus fleet is presented. Based on the collected statistical data, the typical causes of trolleybus failures were identified. It has been shown that the largest number of trolleybus failures is associated with electrical equipment malfunctions. It is determined that one of the most promising ways to reduce the number of failures is to improve the reliability of current collectors. To this end, the general state of affairs in this field was analyzed. A method for improving the reliability of current collector operation in adverse weather conditions is proposed. To solve this problem, it is proposed to change the design of the current collectors. The existing ways of solving this problem are investigated. The advantages and disadvantages of the existing methods are determined. The paper proposes a new constructive solution, which, according to the authors' idea, allows solving the problem. The essence of the solution is the simultaneous installation of two current-collecting inserts on the current collector rod. The current collecting inserts used have different physical properties and, when working together, improve the operating conditions of the trolleybus current collecting system. The proposed solution reduces the number of trolleybus current-collecting rod disconnections from the contact network. This leads to an increase in the stability of the trolleybus electrical system. At the same time, the operating conditions of the mechanical part of the trolleybus structure are improved. This leads to an increase in the stability of the trolleybus electrical system. At the same time, the operating conditions of the mechanical part of the trolleybus structure are improved. By reducing the number of forced braking of the trolleybus, the level of safety and comfort of passengers increases. Reducing the total number of failures of the current collector system and reducing the level of loads on the mechanical systems of the trolleybus allows to increase the overhaul mileage and reduce the level of costs in the operation of the trolleybus fleet

Alignment Controlled Aramid Nanofiber‐Assembled Films

AbstractAramid nanofibers (ANFs) are a strong and heat‐resistant nanomaterial that can be isolated from commercial para‐aramid fibers, which allow a bottom‐up self‐assembly to form ordered macroscale structures like ANF films. However, the anisotropic nature of high aspect ratio ANFs is not fully exploited when fabricating ANF films for the optimal mechanical properties. In this research, direct ink writing (DIW) is applied to produce ANF‐assembled films with arbitrary shapes, and the shear‐induced alignment of ANFs can follow the printing path direction. Therefore, controlled alignment of ANFs following the computer‐programmed printing pattern is achieved by DIW, which provides a path for the application of topology and nanofiber alignment optimization in nanofiber‐assembled films. In addition, the resulting DIW ANF films exhibit outstanding Young's modulus of 8.39 GPa, tensile strength of 198 MPa, and tensile toughness of 19.4 MJ m−3 in the alignment direction, together with a wide working temperature range up to 440 °C without losing 50% of its room temperature storage modulus. Moreover, the demonstrated self‐joining ability, rollability, and lamination processability of the DIW ANF films expand their potential applications toward high‐temperature ultrathin tubes, substrates for flexible printed circuit boards, and three‐dimensional all‐ANF lightweight structural parts in extreme environments.

Heat affected zone liquation cracking evaluation on FeMnAl alloys

ABSTRACT FeMnAl steels are currently generating a lot of interest with potential applications for structural parts in armored vehicles due to their lower density and outstanding mechanical properties. Despite the extensive mechanical performance and heat treatment exploration of this alloy class, further weldability investigation is required for future large-scale deployment. In the present study, the liquation cracking of four heats of cast FeMnAl alloys was investigated by the spot-Varestraint technique. The study focuses primarily on the effect of the major elements of the FeMnAl system: C, Mn and Al. Optical and electron microscopy was employed to investigate the microstructural features and CALPHAD was employed to aid the discussion regarding the alloy’s composition differences and their effect on the liquation cracking susceptibility. The study was able to identify that compositions with the higher Mn, C and lower Al presented the highest liquation cracking susceptibility. Conversely, composition presenting lower Mn, C, and Al showed the most resistant behavior. Furthermore, lower Al content promoted a fully-γ microstructure at low temperatures, which encouraged the appearance of longer cracks as a γ-matrix is more susceptible to HAZ cracking than a fully ferritic (α) or duplex (α + γ) microstructure.

Study of structural parameters of petroleum acids and analysis of their possible negative impact on the environment

Study of the structural parameters of petroleum acids isolated from oil from the Priozernoye field and analysis of their possible negative impact on the environment.The object of the study is and naphthenic acids isolated from the oil of the Priozernoye field. The research was carried out using modern instrumental methods: gas‐liquid chromatography, IR‐spectroscopy, 13C NMR, 1H NMR spectroscopy and elemental analysis.The high degree of oxidation of the oil studied was confirmed. Extraction with dichloromethane and subsequent analysis of the organic extract using IR‐Fourier spectrometry proved that part of the petroleum acids entered the aqueous phase, which poses a serious threat to the biological diversity of this region. The structural parameters of “medium” molecules of petroleum acids isolated by leaching from three distillate fractions of this oil have been established. It is shown that the products isolated during leaching have a molecular weight of 294–574 amu and contain from 20 to 40 carbon atoms, most of which are part of the naphthenic structures. Along with petroleum acids, leaching products include hydrocarbons.Comparison of the structural parameters of the products isolated from the fractions of the studied oil with the data in the scientific literature allows us to qualify the acids contained in the oil of the Priozernoye field as being substances with high toxicity, which requires finding ways to solve the problem of ensuring the environmental safety of this region.

General upper limit on the electric charge of Sgr A* in the Reissner–Nordström metric

ABSTRACT In general relativity, the gravitational field of an electrically charged, non-rotating, spherically symmetric body is described by the Reissner–Nordström (RN) metric. Depending on the charge to mass ratio, the solution describes a black hole or a naked singularity. In the naked-singularity regime, a general property of this metric is the existence of a radius, known as the zero-gravity radius, where a test particle would remain at rest. As a consequence of repulsive gravity there is no circular orbit inside this radius, and at least a part of any quasi-stable structure must necessarily lie outside of it. Assuming the iconic torus in the compact source Sgr A* at the Galactic centre observed by the Event Horizon Telescope (EHT) to be the image of a quasi-stationary fluid structure, we provide rigorous constraints in the RN metric on the electric charge-to-mass ratio Q/M of Sgr A*. A comparison between the EHT observations and the space–time zero-gravity radius provides the most conservative limit on the charge of Sgr A* to be |Q/M| < 2.32 in geometrized units. A charged naked singularity respecting this charge-to-mass constraint is consistent with the current EHT observations, if the image is not interpreted as a photon ring.

3D printed orthopedic prostheses for domestic and wild birds—case reports

Regardless of the species, birds are exposed to injuries that lead to amputation of part of the body structure and often euthanasia. Based on the need for new technologies that improve the quality of life of birds with locomotor problems, the present case reports aimed to describe the development of custom-made three-dimensional (3D) prostheses for domestic and wild birds that suffered amputation or malformation of the hind limb. Using the measurements of the bird, a digital model was created for 3D printing using fused deposition modeling technology (FDM) by the Brazilian company 3D Medicine. In this study we report the use of 3D prosthesis for the rehabilitation of three birds with locomotor disorders in Brazil, the animals adapted to the custom-made prosthesis with an improvement in quality of life, better distribution of body weight, locomotion, and landing. This study describes the development of 3D prostheses for birds in Brazil, the first report of this technology for these species, and the pioneering development of socket prostheses for small birds. 3D prostheses offer a high-efficiency solution to improve the quality of life of animals with amputations and malformations of the hind limbs. In addition, 3D technology provides valuable tools for veterinary medicine, developing custom-made models for the most different anatomical demands of animal patients.

Sawtooth structure in tunneling probability for a periodically perturbed rounded-rectangular potential.

Sawtooth structures are observed in tunneling probabilities with changing Planck's constant for a periodically perturbed rounded-rectangular potential with a sufficiently wide width for which instanton tunneling is substantially prohibited. The sawtooth structure is a manifestation of the essential nature of multiquanta absorption tunneling. Namely, the periodic perturbation creates an energy ladder of harmonic channels at E_{n}=E_{I}+nℏω, where E_{I} is an incident energy and ω is an angular frequency of the perturbation. The harmonic channel that absorbs the minimum amount of quanta of n=n[over ¯], such that V_{0}<E_{n[over ¯]}≤V_{0}+ℏω, makes a dominant contribution to the tunneling process, where V_{0} is the height of the static potential and V_{0}-E_{I}≫ℏω. At each steep slope part of the sawtooth structure, replacement of the dominant harmonic channel, i.e., E_{n[over ¯]}→E_{n[over ¯]+1}, occurs and the tunneling probability suddenly drops with increasing 1/ℏ. Due to the flatness of the potential top, resonance eigenstates exist just above the potential and the first resonance state appears as the peak of each edge of the sawtooth structure for the tunneling probability in the potential region. Sawtooth structures are also observed with changing the perturbation frequency. We introduce an effective formula to characterize the basic profile of those sawtooth structures.

Characteristics of packing gland seals in hydraulic systems of quarry excavators and results of comparative analysis of experimental tests

The efficiency of quarry hydraulic excavators will depend on several factors, namely the climatic conditions of the area where hydraulic excavators are used, the degree of air pollution (pollination), the performance of the structural parts of the excavator, the reliability of the hydraulic system, the performance and cleanliness of the hydraulic working fluid. In this area, research was carried out on the performance of seals used in the hydraulic system of quarry excavators. The article presents the results of experimental tests of the existing type of oil seal a and b, as well as the proposed oil seal type c, shown in Fig. 1.