Mechanical Engineers Research Articles

MINING MACHINE SIMULATION MODEL REFINEMENT ACCORDING TO THE ENGINES ENERGY CONSUMPTION DATA

The importance of mining factories planning for ore extraction is indicated. The created simulation model with open and normative data is presented. Significant deviations of the simulation results from the real data of the mining machines monthly operating time of are shown. The goal is to refine the model with the available mining machine operation real data. As a source of data, it is proposed to use miming machines engines energy consumption. The source this information is described. Information about the mining machine engines is given. That information can be used for mining machines analyzing to determine the times of the states. There are 8 such engines in total, their sequential switching on and off allows us to understand the time of 4 technological operations that make the greatest contribution to the mining machines operating time. A fragment of the algorithm which allows to determine the operations time is given. Two combines were selected with the production differs most from the model in the direction of increase and decrease. For both combines the duration of ore breaking and ore loading from the storage hopper to the self-propelled car is determined. First, an analysis was made for the mining machine that breaks more ore than was obtained in the calculations. The analysis showed the existence of a previously undescribed state of the mining machine-simultaneous ore breaking into the storage hopper and ore loading from the storage hopper to a self-propelled car After including that state in the model, a new calculation was made. Calculation shows increasing in the model total output. In addition, analysis was made of the existing stochastic delay during ore breaking. Analysis shows that statistical distribution stochastic delay can corresponds to a negative binomial distribution. Further, the study of data for a mining machine with the producing less than the model amount was carried out. It allows to study the stochastic delay during ore loading. It is shown that such a delay can also correspond to a negative binomial distribution. The simultaneous inclusion of described delays significantly reduces the total estimated production amount. In conclusion, it is discussed that the simultaneous addition of a new state and stochastic delays with a negative binomial distribution to the model significantly reduces the modeling error.

Review: Air-Conditioning in Modern American Architecture, 1890–1970

Review: <i>Air-Conditioning in Modern American Architecture, 1890–1970</i>

Guest Editorial: Learning, optimisation and control of cyber‐physical systems

Guest Editorial: Learning, optimisation and control of cyber‐physical systems

Distributed Continuous and Discrete Time Projection Neurodynamic Approaches for Sparse Recovery

Sparse representation acts as a fundamental data science methodology for solving a wide range of problems in machine learning and engineering. In this paper, we respectively propose novel distributed continuous-time and discrete-time projection neurodynamic approaches for sparse recovery by seeking the minimum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> -norm solution with the undetermined linear measurement <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$Ax=b$</tex-math></inline-formula> in two cases over undirected networks. The proposed approaches only require the communication network to be undirected and connected, without the notion of central processing node, and no node visit the entire matrix <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$A$</tex-math></inline-formula> , so some privacy preserving efficiencies are guaranteed based on our approaches. First, for the one case that the rows of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$A$</tex-math></inline-formula> are distributed, we propose a distributed continuous-time projection neurodynamic approach based on the projection operators and prove the global convergence and optimality of it. Then, a corresponding distributed discrete-time projection neurodynamic algorithm with a fixed step size is also presented, and the convergence and the scope of values of the step size of it are also analyzed. Second, for another case that the columns of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$A$</tex-math></inline-formula> are distributed, a distributed continuous-time projection neurodynamic approach based on the projection operators and its derivative feedback is proposed and its global convergence is rigorously analyzed. Immediately following, we discuss its corresponding distributed discrete-time projection neurodynamic algorithm with a discrete version of the differential feedback term. Finally, the effectiveness and superiority of the proposed neurodynamic method are verified by the experiments of sparse signal and image reconstruction.

Research and Prospect of Wave maker Design and Wave making Application

Wave energy is clean energy with huge development potential. At present, structural energy reform is an important issue in my country’s development. Therefore, the research on the application of wave energy can promote the structural reform of my country’s energy to a certain extent. This paper summarizes the history of wave simulation development and the current status of wave applications, and compares and analyzes wave-making by pushing plate-type wave machines, rocking plat-type wave machines, box-type wave machines, and combined wave-making according to different wave-making methods. Machine building characteristics. Combined with the application status of wave energy, the wave energy power generation is summarized, and the economic and technical status of wave energy power generation is described in detail. Finally, the development trend and application prospect of wave application are summarized.

Boosting productivity with tech

Boosting productivity with tech

ВИКОРИСТАННЯ ІНФОРМАЦІЙНИХ ТЕХНОЛОГІЙ У ПРОФІЛЬНІЙ ПІДГОТОВЦІ СТУДЕНТІВ ІНЖЕНЕРНО-ПЕДАГОГІЧНИХ СПЕЦІАЛЬНОСТЕЙ

The article deals with the problem of using information technologies in the process of specialized training of students of engineering and pedagogical specialties. The aim of the article is to reveal the essence and peculiarities of the use of information technology in the training of future vocational teachers; to identify the problems of classical teaching methods and to find ways to solve them through the use of information technology. A set of research methods was used, namely: content analysis, generalization and specification of the provisions of the Standards of Higher and Vocational Education of Ukraine, educational programs and curricula, designing the content and structure of an e-learning course, substantiation of the conditions for using e-learning courses in the process of specialized training of students. Results of the study. The Standard of Higher Education of Ukraine, specialty 015 Vocational Education (by specialization), first (bachelor) level, was analyzed. The existing curricula for the training of vocational teachers of transport profile were examined for their compliance with the requirements of educational standards. It has been determined that the normative part of the curriculum includes cycles of general and professional training which contain blocks of fundamental, psychological, pedagogical and methodological, scientific and subject, and practical training. It has been found out that the courses that form the special competencies of vocational teachers of transport profile belong to the block of scientific and subject training. The courses that form the special competencies of transport vocational teachers are highlighted, namely: vehicles and their maintenance, transport logistics, electrical and information-computer systems in transport, traffic rules, operation and repair of transport machine engines, interchangeability, standardization and technical measurements, and technical mechanics. Traditional approaches to the study of these courses are investigated in order to identify the main shortcomings. It has been stated that the traditional methodology of conducting classes involves significant time spent on note-taking of educational material, which can be mastered with greater efficiency using information and communication tools. Ways to eliminate the shortcomings of traditional approaches to the study of specialized courses are proposed, one of which is the development and implementation of e-courses on the Moodle platform, since this platform allows combining different formats of information, makes it possible to timely update the educational material in accordance with the pace of development of the transport industry, as well as it is easy to use and supported by most modern Smart devices. The structural and functional components of the e-learning course are defined including an information and organizational component; a training component; an information and reference component; and a practical component. The requirements for creating and implementing e-learning courses in the educational process are generalized. An e-learning course on the Moodle platform in the Transport Logistics course has been developed. It consists of information and methodological, training, control and evaluation, and reference blocks. A description of the content of these structural blocks is presented. Prospects for further research are identified; these are development of methods for using e-learning courses in specialized subjects in a mixed form of education under martial law.

Shell and tube heat exchanger design for waste water cooling

This paper presents the design of a hull and tube heat exchanger, including thermal calculation, until the definition of the geometry of its mechanical components. The service to which this exchanger will be designed, and to cool the disposal of the water used in the cooling process of a steel rolling mill. Then the mechanical design is presented, where the materials are specified and the dimensions are calculated for the main components of the exchanger. The TEMA (Tubular Exchanger Manufacturers Association) and ASME (American Society of Mechanical Engineers) standards were the main international standards on which the mechanical design was based.

A phenomenological law for complex granular materials from Mohr-Coulomb theory

Manipulating powders still entails some clumsy and risky operations even now in the middle of the fourth industrial revolution. This is because there is a lack of well-understood theory about granular matter due to its ravelled complexity. However, granular matter is the second most handled material by man after water and is thus ubiquitous in daily life and industry only after water. Since the eighteenth century, mechanical and chemical engineers have been striving to manage the many difficulties of grain handling, most of which are related to flow problems. Many continuum models for dense granular flow have been proposed. Herein, we investigated Mohr–Coulomb failure analysis as it has been the cornerstone of stress distribution studies in industrial applications for decades. This research gathers over 130 granular materials from several industrial sectors, as varied as cement and flour, including raw materials, food, pharmaceuticals, and cosmetics. A phenomenological law derived from the yield locus and governed exclusively by one dimensionless number from adhesive interactions has been found. Surprisingly, and in contrast to the common perception, flow in the quasi-static regime is actually independent of the friction, the packing fraction and any other grains/bulk intrinsic properties. The simplicity and accuracy of the model are remarkable in light of the complex constitutive properties of granular matter.

Study of the performance indicators of synthetic motor oils used in petrol engines of Škoda Rapid passenger cars

The aim of the work is to study the change in kinematic viscosity and base number of imported and domestic synthetic motor oils used in gasoline internal combustion engines with an increase in the mileage of a Škoda Rapid car. The scientific novelty of the work consists in obtaining new experimental data on the change in kinematic viscosity and base number in synthetic motor oils of domestic and foreign brands with an increase in vehicle mileage. The introduction contains brief information on the requirements for kinematic viscosity and base number in synthetic motor oils used in gasoline internal combustion engines of passenger cars. The main part describes the methodology for conducting research to determine the kinematic viscosity of motor oils and base number, depending on the mileage of the car. It has been established that it is advisable to use ʻʻLukoil Lux SAE 5W-40ʼʼ, ʻʻLukoil Genesis Armortech Jp 5W-30ʼʼ and ʻʻNaftan Garant SAE 5W-40ʼʼ oils as synthetic motor oil for gasoline engines of Škoda Rapid brand cars, due to the fact that the studied performance indicators of the indicated oils are less intensively reduced during the operation of the car, which in turn indicates a higher quality of these oils. It was also established that the replacement of ʻʻNaftan Premier SAE 5W-40ʼʼ synthetic motor oil should be carried out after a car has run 7.5 thousand km. In turn, the replacement of the remaining synthetic motor oils under study should be carried out after 12 thousand kilometers. The results of the research will be useful to mechanical engineers when choosing a brand of synthetic motor oil used in the operation of Škoda Rapid passenger cars in order to increase the reliability and performance of the main engine components.

Perspective on “code qualifying” new graphite grades for use in advanced nuclear reactors*

The American Society of Mechanical Engineers (ASME) publishes the Boiler and Pressure Vessel (BPV) Code, which include guidance for the safe development, construction, and operation of boilers and pressure vessels. ASME BPV Code Section III “Rules for Construction of Nuclear Facility Components” Division 5 focuses on “High Temperature Reactors”. Subsection HH, subpart A lists the different materials properties that are to be measured and how those properties change due to different environmental conditions (oxidation and irradiation damage) for a graphite to be accepted for use in a high temperature reactor core (i.e., “Code Qualified”). Currently there are no nuclear graphite grades that are “Code Qualified” (i.e., a reactor designer can select a graphite grade and build their reactor without any additional testing), which is due in part to development of new graphite grades in the last 20 years and the lack of comprehensive programs needed to produce the data for the code cases. This perspective is going to discuss the requirements, as called out in the ASME BPV Code, that are necessary to “code qualify” a nuclear graphite grade but will primarily focus on the practical and technical challenges associated with irradiation-induced property changes and how to address these to assist with getting graphite ready for use in advanced nuclear reactors. These same technical challenges can be expected to arise for other materials being developed for advanced reactor concepts.

Quenching of EN-8 Medium Carbon Steel in Salt Bath of Different Concentrations

Heat treatment of metals and alloys is an important operation in the final fabrication of several engineering parts. Heat treatment and microstructure studies have always been a wide area of research for mechanical and metallurgical engineers. The application of different quenchants for cooling process has further has widened the scope of quenching. This experimental work is concentrated on the microstructure of EN-8 medium carbon steel cast samples when heat treated at different temperatures and quenched in different types of quenchants. The properties of this steel got affected due to sudden quenching. The microstructure of the steel was analysed and it was subjected to Rockwell hardness tests. Increase in hardness value of the samples was determined. The change in microstructure was studied.

Investigating the Friction Behavior of Turn-Milled High Friction Surface Microstructures under Different Tribological Influence Factors

The coefficient of friction (COF) is an important parameter for mechanical engineers to consider when designing frictional connections. Previous work has shown that a surface microstructuring of the harder friction partner leads to a significant increase in the COF. However, the impact of the changes in the tribological system on the COF are not known in detail. In this study, the tribological influence factors such as the nominal surface pressure, the material pairing, lubrication, and the surface properties of the counterbody are investigated. Microstructuring is applied by turn-milling of an annular contact surface of cylindrical specimens. A torsional test bench is used to measure the torque depending on the displacement of the two specimens, thus enabling the determination of the COF. All tests with the microstructured specimens result in higher COF than the reference test with unstructured samples. The manufacturing process of the counterbody surface, the nominal surface pressure, and the materials in contact have a significant influence on the COF. While lubrication reduces friction in the case of unstructured specimens, the COF does not change significantly for microstructured samples. This proves that the deformative friction component dominates over the adhesive. Microstructuring the harder friction partner increases the transmittable torque in frictional connections and reduces the sensitivity towards possible contamination with lubricants.

EMHD Nanofluid Flow with Radiation and Variable Heat Flux Effects along a Slandering Stretching Sheet.

Nanofluids have gained prominence due to their superior thermo-physical properties. The current paper deals with MHD nanofluid flow over a non-linear stretchable surface of varying thickness in the presence of an electric field. We investigated the effects of nanometer-sized copper (Cu) particles in water (base fluid) as a nanofluid, as well as non-linear thermal radiation, variable fluid viscosity, Joule heating, viscous dissipation, and non-uniform heat flux. The current study's aim is influenced by the immense applications in industry and machine building. It has been observed that linear stretching sheets have been extensively used in heat transfer research. Moreover, no effort has been made yet to model a non-linear stretching sheet with variable thickness. Furthermore, the effects of electromagnetohydrodynamics (EMHD) boundary-layer flow of a nanofluid with the cumulative impact of thermal radiation, variable viscosity, viscous dissipation, Joule heating, and variable heat flux have been investigated. Sheets with variable thicknesses are practically significant in real-life applications and are being used in metallurgical engineering, appliance structures and patterns, atomic reactor mechanization and paper production. To investigate the physical features of the problem, we first examined the model and identified all the physical properties of the problem. This problem has been formulated using basic laws and governing equations. The partial differential equations (PDEs) that govern the flow are converted into a system of non-dimensional ordinary differential equations (ODE's), using appropriate transformations. The Adam-Bashforth predictor-corrector technique and Mathematica software are utilized to numerically solve the resulting non-dimensionalized system. The interaction of various developing parameters with the flow is described graphically for temperature and velocity profiles. It is concluded that the velocity of nanoparticles declines as the intensity of the magnetic field increases. However, the temperature of the nanomaterials rises, as increasing the values of the electric field also increases the velocity distribution. The radiation parameter enhances the temperature field. The temperature of the fluid increases the occurrence of space- and time-dependent parameters for heat generation and absorption and radiation parameters.

Mathematical simulation of the automatic control of the tractor power unit

BACKGROUND: Many manufacturers of agricultural tractors have machines with automatic gearboxes in their product line. The development of the design of this type of transmissions, the control system and the algorithm of its operation is an urgent technical task.&#x0D; The article considers the issues of mathematical simulation of the working process of the automatic transmission of a wheeled tractor and the automatic transmission control system.&#x0D; AIMS: The purpose of the work was to determine the optimal control laws of automatic control of a wheeled agricultural tractor engine and transmission in various operating modes using a digital model of the tractor transmission.&#x0D; METHODS: Simulation of working conditions is performed in the Matlab program digital software packages and its applications Simulink, Simscape. At the same time, with the help of fundamental data blocks of these applications, models of the physical components of the gearbox and the machine engine and the tractor power transmission control system, are created.&#x0D; RESULTS: The application procedure of the MATLabSimulink, Simscape software package for mathematical modeling of transmission operation control is considered. With the help of the developed mathematical model, a simulation of the tractor power unit operation in the main operating modes was carried out in order to optimize the characteristics of the tractor control system.&#x0D; The scientific novelty of the research lies in the selection and optimization of the transmission control laws in accordance with the requirements to agricultural tractors with an automatic step gearbox.&#x0D; CONCLUSION: The practical utility (value) of the research lies in the possibility of using the proposed control laws to develop a transmission control system for new tractors with an automatic step gearbox.

BIM adoption and maturity anno 2021: a large scale empirical study on the current state of affairs

This large-scale study aims to get insight in the level of BIM adoption and maturity in the Dutch construction industry. In this study, the focus is on BIM users, BIM non-users and those that are unaware and do not use BIM in six subsectors (principals, architects, engineers, contractors, suppliers and mechanical engineers) and the construction industry as whole. In total 725 respondents participated in this interview-based study, 235 of them actually used BIM (the BIM-users) and 342 knew about BIM but did not use it (the BIM non-users). The remaining 148 did not know about BIM and therefore were not able to answer the questions related to BIM and BIM-use. The architects and suppliers have the highest number of BIM-users, mechanical engineers and contractors the lowest. One third of the contractors and mechanical engineers in this study was not aware of BIM. For measuring BIM-maturity, firms were asked questions about BIM-strategy, organization- and project-structure, human & culture, BIM-processes, IT and data(-structure). The score for each criterion is a mean of the sub criteria that are part of that criterion. The overall BIM-maturity is a mean of these sub criteria. The overall BIM-maturity of the architects was the highest and of the principals and engineers the lowest. ICT component is the highest scoring BIM-maturity component within the entire construction sector while BIM-processes the lowest scoring component. The findings from this study can be used to inform organizations in specific subsectors of construction in which aspects of BIM they have to invest to increase maturity.

Historical evolution of robot-assisted cardiac surgery: a 25-year journey.

Many patients and surgeons today favor the least invasive access to an operative site. The adoption of robot-assisted cardiac surgery has been slow, but now has come to fruition. The development of modern surgical robots took surgeons close collaboration with mechanical, electrical, and optical engineers. Moreover, the necessary project funding required entrepreneurs, federal grants, and venture capital. Non-robotic minimally invasive cardiac surgery paved the way to the application of surgical robots by making changes in operative approaches, instruments, visioning modalities, cardiopulmonary perfusion techniques, and especially surgeons' attitudes. In this article, the serial development of robot-assisted cardiac surgery is detailed from the beginning and through clinical application. Included are references to the historical and most recent clinical series that have given us the evidence that robot-assisted cardiac surgery is safe and provides excellent outcomes. To this end, in many institutions these procedures now have become a new standard of care. This evolution reflects Sir Isaac Newton's famous 1676 quote when referring to Rene Descartes, "If have seen further [sic] than others, it is by standing on the shoulders of giants".

The Impact of Modern Topo-Geodetic Technologies on Positioning Techniques

&#x0D; The field of constructions has evolved extraordinarily in terms of measurement techniques, requiring increasing accuracy. This has led to the creation of new specific technologies, and implicitly measuring instruments. The range of classical geodetic measuring instruments has been completed with new high precision instruments, even in the field of physics or machine building. The use of geodetic measurement methods in the field of Engineering Topographic Measurement Techniques involves, in addition to ensuring precision requirements, the choice of appropriate devices and technologies. This choice is imposed both by the previous precision calculations, starting from a maximum permissible deviation given, and by the knowledge of the execution and assembly technologies. The purpose of this paper was to study the effect and also the impact that new technologies had on the main measurement activities, and of course on measurement techniques. This review article summarizes, analyzes and discusses the current state of primary research in terms of the impact of current or developing technologies on geodetic techniques. The global corpus of primary research is growing at an unprecedented rate. It is difficult for most researchers to grasp the state of the art of a topic. A vast number of bibliographic references were taken into account, on which analyzes were performed.&#x0D;

Effects of Severe Plastic Deformation and Ultrasonic Treatment on the Structure, Strength, and Corrosion Resistance of Mg-Al-Zn Alloy.

Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction and equal channel angular pressing, as well as the subsequent ultrasonic irradiation on the structure, strength, and corrosion properties of the Mg-Al-Zn alloy. Deformation processing results in an increase of the strength up to 280 ± 10 MPa. A fine-grained structure is formed with a grain size of 10–20 µm and small recrystallized grains 1–2 µm in size. The corrosion resistance in the HCl medium falls down significantly. Action of ultrasound on the deformed specimen leads to an increased fraction of high-angle boundaries, in particular, the fractions of special, fully overlapping Σ13a boundaries and twin boundaries of Σ15b and Σ17a systems. Due to the ultrasonic treatment, the strength of the Mg-Al-Zn alloy increases up to 310 ± 5 MPa, while the corrosion resistance in HCl almost doubles.

COMPARISON BETWEEN SOLAR THERMAL-POWERED ABSORPTION REFRIGERATION CYCLE AND PHOTOVOLTAIC-POWERED COOLING TECHNOLOGIES APPLIED TO DATA CENTERs

The air conditioning system of a Data Center is a great challenge for mechanical engineers. At the same time, it is fundamental for computer safety, it is a great energy consumer. Considering that, the present work carried out an analysis in which a solar-powered absorption refrigeration cycle system is combined with a conventional electrical chiller system. The proposed system also introduces the use of PV panels to generate electricity to power the electric chiller. A decision algorithm was developed based on local solar parametric data and cooling demand. A case study was analyzed for a typical data center located in the city of São Paulo, Brazil. Electrical specific installed power demands of 0.5, 1.0, 2.0, 4.0, and 8.0 kW/m² at half and total load were studied. Local solar irradiation and temperature indexes were based on the data obtained from ASHRAE [1]. The results show that, for a typical year, the absorption solar system performs better than the photovoltaic system in most cases (0.5, 1.0, 4.0, and 8.0 kW/m²), except when the baseline of the installation operates near the optimum point of the consumption curve of the chiller, which occurs at 2 kW/m². Finally, the study shows that air conditioning systems powered by solar energy are a great alternative to reduce the energy consumption and operational costs of a Data Center.