General Engineering Research Articles

Free element boundary integration method for solving heat conduction and mechanics problems

In this paper, a novel numerical method called the free element boundary integration method (FEBIM) is proposed for solving general engineering problems on the basis of the free element method (FrEM). The proposed method is a weak-form FrEM, which approximates physical quantities through isoparametric elements as in finite element method. The characteristic of FEBIM is that each used isoparametric element can be freely composed by the collocation node and its surrounding nodes. The main difference of FEBIM from FrEM is that the governing equations for internal nodes and the equilibrium equations for boundary points are transformed into boundary integrals in FEBIM. The source point of the local boundary integrals is the collocation node. As a result, FEBIM not only has the advantage of narrower bandwidth over FrEM, but also has higher computational precision, since the second-order derivative is not involved in the process of forming the equations. Numerical examples of heat transfer and solid mechanics problems are given in the paper to verify the correctness and stability of the proposed method.

Bone Formation in 2D Culture of Primary Cells.

Relevance of mineralized nodules in two-dimensional (2D) osteoblast/osteocyte cultures to bone biology, pathology, and engineering is a decades old question, but a comprehensive answer appears to be still wanting. Bone-like cells, extracellular matrix (ECM), and mineral were all reported but so were non-bone-like ones. Many studies described seemingly bone-like cell-ECM structures based on similarity to few select bone features in vivo, yet no studies examined multiple bone features simultaneously and none systematically studied all types of structures coexisting in the same culture. Here, we report such comprehensive analysis of 2D cultures based on light and electron microscopies, Raman microspectroscopy, gene expression, and in situ messenger RNA (mRNA) hybridization. We demonstrate that 2D cultures of primary cells from mouse calvaria do form bona fide bone. Cells, ECM, and mineral within it exhibit morphology, structure, ultrastructure, composition, spatial-temporal gene expression pattern, and growth consistent with intramembranous ossification. However, this bone is just one of at least five different types of cell-ECM structures coexisting in the same 2D culture, which vary widely in their resemblance to bone and ability to mineralize. We show that the other two mineralizing structures may represent abnormal (disrupted) bone and cartilage-like structure with chondrocyte-to-osteoblast transdifferentiation. The two nonmineralizing cell-ECM structures may mimic periosteal cambium and pathological, nonmineralizing osteoid. Importantly, the most commonly used culture conditions (10mM β-glycerophosphate) induce artificial mineralization of all cell-ECM structures, which then become barely distinguishable. We therefore discuss conditions and approaches promoting formation of bona fide bone and simple means for distinguishing it from the other cell-ECM structures. Our findings may improve osteoblast differentiation and function analyses based on 2D cultures and extend applications of these cultures to general bone biology and tissue engineering research. Published 2022. This article is a U.S. Government work and is in the public domain in the USA. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A parametric model on thermal evaluation of building envelopes containing phase change material

Appropriate methods for introducing phase change materials (PCM) into building envelopes (including walls and roofs) and performance investigation methods are essential for the thermal application of buildings equipped with PCMs. However, most of the existing evaluation methods, including numerical simulations and physical tests, are expertise-required, along with economic and time costs. In this paper, a thermal performance database covering 2401 different configurations of PCM-filled building envelopes is developed and performance trends of the envelopes are summarized based on the calculation of a validated enthalpy mathematical model. Based on the values in the database, a new parametric model of two mathematical equations for evaluating the thermal index values of PCM-filled envelopes is proposed. The average relative error of the model was 7.7 % compared to the numerical results. With a thermal resistance of 1 m2·K·W−1 or higher and an indoor-outdoor temperature difference of 5 °C or higher, the model is applicable to most PCM-outfitted envelopes under the thermal conditions throughout a year, and can be used not only for thermal index calculations, but also for parameter value optimization and configuration improvement. The purpose of this study is to provide an approach for fast evaluation by professionals, and offer a friendly tool for general architects and engineers for the thermal investigation and optimization of building envelopes containing PCM.

Kelayakan media flash flipbook pada submateri darah

This study aims to determine the feasibility of flash flipbook as a medium for sub blood material learning. The research method is descriptive with survey and the research instrument is a validation sheet. The feasibility of flash flipbook was measured through material validity test and media validity test. The validation aspect of flash flipbook material consists of format, content, and language. The aspect of media validation from flash flipbook consists of general aspects, soft engineering, visual engineering, and audio communication. The results of flash flipbook validation obtained an average value of validation by material experts 3.35 valid criteria and the average value of validation by media experts 3.42 valid criteria. It can be concluded that flipbook flash is suitable to be used as a learning medium on sub blood material.

Multiple linear regression based model for the indoor temperature of mobile containers

It is important to work out precise and easy-to-use mathematical models to predict the indoor temperature in buildings for human residence. Such models can support model-based/predictive controls to efficiently maintain the temperature at a comfortable level.Accordingly, as main contribution, the paper proposes a new, easy-to-use, black-box type, multiple linear regression (MLR) based model for the indoor temperature of mobile (office) containers. The model, having low computational demand, could be easily generalized for different types of residence places (in the future).A discretized, physically-based model version of the classical, widely used heat transfer theory (based on energy balance) is recalled for comparison with the MLR-based model.Both models have the same (exogenous) inputs: global solar irradiance, environment temperature and wind speed.Both models are validated based on measured data. The MLR-based model is more precise, its modelling error is 7.1%, which means that it can be used well for general engineering aims.Moreover, the model is detailed in time (it gives an output value per half minute), so it could be properly used for real-time prediction and control purposes.Another contribution of the paper is that the MLR-based model is used to estimate the application potential of solar collectors, installed on the top of the container, for space heating. Based on the results, two solar collectors could extend the time with comfortable indoor temperature by more than 5 h within a three-day period in spring (in Hungary).Finally, conclusions and possible topics for future researches are provided.

Nano-Biohybrid DNA Engager That Reprograms the T-Cell Receptor.

Although engineered T cells with transgenic chimeric antigen receptors (CARs) have made a breakthrough in cancer therapeutics, this approach still faces many challenges in the specificity, efficacy, and self-safety of genetic engineering. Here, we developed a nano-biohybrid DNA engager-reprogrammed T-cell receptor (EN-TCR) system to improve the specificity and efficacy, mitigate the excessive activation, and shield against risks from transgenesis, thus achieving a diversiform and precise control of the T-cell response. Utilizing modular assembly, the EN-TCR system can graft different specificities on T cells via antibody assembly. Besides, the designability of DNA hybridization enables precise target recognition by the library of multiantigen cell recognition circuits and allows gradual tuning of the T-cell activation level by the signaling switch and independent control over different types of T cells. Furthermore, we demonstrated the effectiveness of the system in tumor models. Together, this study provides a nongenetic T-cell engineering strategy to overcome major hindrances in T-cell therapy and may be extended to a general and convenient cell engineering strategy.

A Redox-Controlled Substrate Engineering Strategy for Site-Specific Enzymatic Fucosylation.

Fucosylation is one of the most common modifications of oligo-N-acetyllactosamine (oligo-LacNAc) glycans. However, none of known fucosyltransferases (FucTs) could install the α1,3-linked fucose to the oligo-LacNAc substrates in a site-specific manner. Here, we report a facile and general redox-controlled substrate engineering strategy for the site-specific α1,3-fucosylation of complex glycans containing multiple LacNAc units. This strategy takes advantage of an operationally simple oxidation enzyme module by using galactose oxidase (GOase) to convert the LacNAc unit into oxidized C6'-aldehyde LacNAc sequence, which is not a good substrate for recombinant α1,3-FucT from Helicobacter pylori strain 26695 (Hpα1,3FucT), enabling the site-specific α1,3-fucosylation at intact LacNAc sites. The general applicability and robustness of this strategy were demonstrated by the synthesis of a variety of structurally well-defined fucosides of linear and branched O- and N-linked glycans.

Recent Progress and Challenges in Microscale Urban Heat Modeling and Measurement for Urban Engineering Applications

AbstractThis review focuses on progress and emerging challenges in experimentally validated modeling of microscale urban thermal environments over the last two decades. In the last few decades, there has been a surge in urban energy contribution resulting in elevated urban day-/night-time air temperatures. While there is no single solution to urban heat, mitigation strategies can be implemented to minimize the harmful effects of urban heat both on humans and the environment. To study the effects of urban heat, numerical modeling of urban thermal environments has seen a rise in usage of several application specific atmospheric modeling software packages, and multiple studies and reviews have already covered the prolific engineering use cases. However, there are inherent and unintentional biases introduced by each modeling software package, that inhibit validity and accuracy for general engineering use. This review critically analyzes the limitations of current state-of-the-art (SOA) microscale atmospheric modeling approaches and identify necessary areas for improvement. Urban thermal environment models must be validated with measurements to gain confidence in the predictive capabilities. This review will additionally examine the next generation of measurement techniques that leverage advances in computing and communications to create distributed meteorological sensor networks for improved spatial and temporal resolutions, that can provide a rich platform for model validation. High fidelity and accurate simulations of urban thermal environments improve confidence in the study of urban heat, its mitigation, and its impact on urban engineering applications in building energy usage and sustainability.

Aspects of implementation of automatic fire containment systems

Introduction. The authors specify the areas of application of automatic fire-prevention systems and the objects that they protect; they also substantiate the main principles of their design and development. Rational hydraulic sprinkler arrangement patterns are designed for automatic water fire-containment systems to be installed in large and small premises, depending on the thermal loading of structures.Goal and objectives. Development of recommendations on the use of automatic fire-containment systems and the objects that they protect.Materials and methods. Fire development patterns were subjected to theoretical and experimental research conducted during variable intensity water supply.Results and their discussion. As a result of this research, general engineering requirements for automatic water fire-containment systems and their testing methods were first developed.Conclusions. The first edition of GOST (All-Russian State Standard) “Automatic water fire-containment systems. General engineering requirements. Testing methods” were addressed to the organizations concerned with this area of knowledge; their opinions and suggestions were contributed to another approved edition of this GOST (All-Russian State Standard).

Review of position statements on antimicrobial resistance and stewardship from professional pharmacy organisations.

Pharmacists play a key role in tackling the global public health threat of antimicrobial resistance (AMR) through contributing to antimicrobial stewardship (AMS) practices. Professional pharmacy organisations describe this AMS role in position statements. Understanding how this role is described, including the why and potential impact is a first step to understanding how this issue is described to the profession, and framed in advocacy. To examine how pharmacy's role in optimising antimicrobial use is articulated in pharmacy professional organisations' position statements. Publicly available AMR position statements were sourced between February 2021 and May 2021 from the available websites of all International Pharmaceutical Federation (FIP) member organisations, supplemented by a general engine search. Descriptive analysis was conducted with a focus on four key themes of interest: 1) rationale for pharmacists' involvement in AMS) 2) characterisation of pharmacists' AMS role; 3) perceived impact of pharmacists' involvement in AMS; and 4) perceived enablers and/or barriers to AMS involvement. 17 position statements were sourced and analysed. Professional pharmacy organisations appear to focus on characterising pharmacists as advisors and educators as their primary role in AMS, with this function supported by their medication knowledge and accessibility as a health service. Specific settings, such as hospital or community pharmacy, were often highlighted in the documents, and were associated with the framing of the capacity and nature of pharmacists' involvement in AMS. However, the limitations of pharmacists and their positions were not discussed. There is an opportunity for future research to explore the concordance between the expectation of pharmacists' involvement in AMS as outlined in these position statements, with the reality of their involvement. This is of importance in the primary care setting, as a key access point to antimicrobials globally.

Estimasi Kemampuan Computational Thingking Pemain Game Dota Dua Menggunakan Teknik Machine Learning

Computational thinking is a way of analytic thinking, a general mathematical thinking approach that may be used in solving a problem, a general engineering thinking approach that allows designing and evaluating large and complex systems that exist in the real world, as well as a general scientific thinking approach in understanding computing ability, intelligence, human mind and behavior. With the existence of online games at a time like today, there is a tendency for many students to play online games because it has its own challenges, many of them even spend a lot of money and even forget the time to play online games. there is an urgency to the level of computational thinking of dota two players, so it is necessary to estimate using machine learning techniques to determine the level of computational thinking of dota two game players. The results of this study provide information that in Estimating the Computational Thinking Ability of Dota Dua Game Players Using Machine Learning Techniques using attribute 6 and rapidminer tools version 10 with operators to be used, including retrieval dataset, role set, correlation matrix, selected by weighted, split data, linear regression, apply model and performance. Produces an error accuracy rate in this study, namely, root mean squered error 0.383 +/- 0.000 Squared error 0.146 +/- 0.016 Squared Correlation 1.000, then this value is the best value from several test results. So it can be estimated as follows that the results of the Computational Thinking Ability are good as much as 36 while the Computational Thinking Ability is sufficient as much as 47

Multi-labeling with topic models for searching security information

Security information such as threat information and vulnerability information are utilized to analyze cyberattacks. If specific keywords such as the name of malware related to the event to be analyzed are known in advance, it is possible to obtain information using typical search engines. However, when a security operator cannot recall appropriate keywords related to the event to be analyzed, or when a commonly recognized identifier does not exist, a general search engine cannot be expected to produce useful results. In this paper, we propose a method using topic models and outlier detection to generate multi-labels for search, with the goal of constructing a search engine that can present relevant security information even in such situations. In addition, this paper discusses the application of the proposed method to 2386 security reports issued from 2017 to 2019 to demonstrate that the labeling can be focused on specific topics.

Failure Analysis – An Overview with Case Study

Failure analysis is an important tool to determine the physical root causes of problems. The process is critical, based upon many different technical disciplines and uses a variety of observation, inspection, and laboratory techniques. It relies on collecting failed components for subsequent examination of the cause or causes of failure using a wide array of methods, especially microscopy and spectroscopy [1]. One of the important parameter in performing a failure analysis is properly observing each and every factor related to failed component and provide unbiased conclusion and corrective action. The objective of failure analysis is to identify whether component or product has failed in service or during manufacturing or during production processing. In any case, one must determine the cause of failure to prevent future occurrence, and/or to improve the performance of the device, component or structure.
 This paper briefly introduces the basics of failure analysis, various modes of failure and the role of failure analysis as a general engineering tool for enhancing product quality and failure prevention. In addition, this paper also covers a typical case study to explain the process methodology in detail.

The effectiveness of the use of information and communication technologies (ICT) in the teaching of general engineering in higher education in Uzbekistan

This paper presents a systematic review of models and methodologies that integrate information and communication technologies (ICT) and education. The starting point of the review is the research questions, then keywords, selection of the databases, definition of the inclusion and exclusion criteria, the definition of the search chains, search process and selection of papers, the analysis of the paper, and the results of the systematic review to answer the questions posed. In the systematic review, 316 papers were found in three academic databases and 75 relevant papers were selected. The work developed intends to know the different models and methodologies that integrate ICT and education. The article describes the solution of problems on the subject "Descriptive geometry and engineering graphics" using computer programs and the role of pedagogical information technologies in the process of teaching students in higher educational institutions. Peculiarities of teaching descriptive geometry and engineering graphics as part of the course of engineering graphics aimed at the mastering of AutoCAD and Compass graphic editor's are considered by the authors. The authors recommend the incorporation of mini-lectures and computer workshops into the training process.

Improved Local Scale Generic Cycle Model for Aerothermodynamic Simulations of Gas Turbine Engines for Propulsion

A local scale Aerothermodynamic Generic Cycle Model (AGCM) is proposed. The AGCM accounts for several improvements not considered in similar models, such as compressor bleed extraction for aircraft Environmental Control System (ECS), parasitic shaft power extraction, and the enthalpy of the fuel entering the combustor. The AGCM is intended for steady-state Design Point (DP) and Off-Design (OD) performance analyses. The underlying physics is presented for the DP model. The turbomachinery component maps scaling and the system of nonlinear equations necessary to define the OD model are thoroughly discussed. The AGCM is compared with an equivalent model developed in the Numerical Propulsion System Simulation (NPSS). The comparisons were performed considering a DP envisioned to approximate a General Electric CF34-8C5B1 engine. The average errors found in these comparisons for the Specific Fuel Consumption (SFC) and net thrust were −0.111% and 0.193%, respectively. Finally, the predictions of the absolute levels of performance intended for the -8C5B1 engine are compared with empirical correlations derived from a comprehensive turbofan engine database. It was found that the predictions of the AGCM are in agreement with the empirical correlations; the errors found in SFC and net thrust at cruise flight condition were −0.43% and 2.06%, respectively.

Reflections on early lunar base design – From sketch to the first moon landing

This paper traces the early ideas of lunar architecture developed by the US and Soviet space programs. Starting with a historical overview of those achievements, highlighting specific engineering, architectural, and design elements; illustrated with images and drawings. Some of them will be described in more detail, showing the design and decision-making process from the first sketch to its implementation.One example of the great engineering and management capabilities is the development and inclusion of the deployable lunar roving vehicle (LRV). Other examples include the project DLB Zvezda by Barmin's Design Bureau of General Engineering that was under development between 1962 and 1974, and a US project Horizon – a study to set up a Lunar Military outpost conducted in 1959. The paper includes personal statements from astronauts and cosmonauts, as well as people involved along design and implementation processes.Based on a historical overview of achievements, this paper highlights particular architectural and design unique approaches that defined design strategies for creating space systems, spacecraft and habitats for decades to follow.

MEEHANITE SF400

Abstract Meehanite SF400 is a ferritic ductile iron that has a minimum tensile strength of 400 MPa (58 ksi) and a minimum elongation of 17%, when measured on test pieces machined from separately cast samples. This fully ferritic Meehanite grade is produced by either strict control of the raw materials during melting or by an annealing heat treatment to eliminate any pearlite formed during solidification. Meehanite SF400 is specifically designed for general engineering applications where high ductility and exceptional resistance to impact is required. It also provides maximum toughness at ambient temperatures. Compared with cast steel of similar strength, it is possible to reduce machining times by up to 25%. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on casting, heat treating, and machining. Filing Code: CI-98. Producer or source: Meehanite Metal Corporation.

Vibration analysis for a parallel fluid-filled pipelines-casing model considering casing flexibility

Ø A dynamic model of a PFFP-C considering casing flexibility is developed. Ø Vibration characteristics of the PFFP with and without casing flexibility are compared. Ø Vibration response of the PFFP under pulsation and displacement excitations is analyzed. The dynamics research of fluid-filled pipelines in the general engineering field has received extensive attention. As the aero-engine pipeline is laid on the casing, the casing flexibility will inevitably affect the vibration state of pipelines. However, the previous investigations have not incorporated casing flexibility in the vibration analysis of aero-engine fluid-filled pipelines. Therefore, a dynamic model of a parallel fluid-filled pipelines-casing (PFFP-C) considering casing flexibility is developed by combining the semi-analytical method and improved transfer matrix method. The relationship between pipelines and casing is established through the flexible support of the casing and the displacement excitation transmitted from the casing to pipelines. The accuracy and significant computational advantage of the proposed model are verified by comparison with the response results of the ANSYS finite element model. The vibration responses of parallel fluid-filled pipelines with and without consideration of casing flexibility are compared. Besides, the frequency response of parallel fluid-filled pipelines under the combined action of fluid pulsation excitation and displacement excitation is also analyzed. The natural frequency and response amplitude of the fluid-filled pipelines have obvious differences after taking the casing flexibility into account, indicating that the influence of casing flexibility on the vibration characteristics of aero-engine pipelines is not negligible. This work can provide potential technical support and theoretical guidance for vibration analysis of aero-engine pipelines.

Computational literacy in science education–A systematic review

Computational literacy is one of the 21st century skills–students must therefore acquire the appropriate competencies in computer science to meet the demands of 21st century society. To achieve this, teachers must be adequately trained. Furthermore, this also means that introductory computer science education concepts must also be integrated into the training of (pre-service) science teachers and anchored in the curriculum. This is particularly important because many scientific professions or research can no longer be done without basic computer knowledge and computational literacy. The central approach to educating future teachers is the university course of study. This paper aims to systematically provide an insight into which scientifically relevant publications address this issue. The essential criterion in this review is the restriction on science education or more general science, technology, engineering, and mathematics (STEM) education in schools or universities. Equally important is the specification that computational literacy (informatics competencies, information literacy, computer literacy, or computational thinking) are purposefully taught or trained. Only publications in the Web of Science database were included for quality assurance. This paper investigates to what extent scientifically valid research or knowledge is available at this junction, i.e., computational literacy in science education. Thereby, we distinguish between different approaches, such as effect studies on individual aspects, isolated practical contributions with a pronounced trial-and-error character, or systematic or model-based considerations in quantitative and qualitative studies. The results show common aspects, prominent trends, and promising approaches. However, possibly existing (subject-) didactic concerns should be considered in more detail and the dual perspective role of the students as future teachers. In addition to learning basic computer skills, the ability to teach them is also essential so that the scientific education of the students can benefit from them to the required extent.

Использование эмпирических методов познания в процессе формирования понятия физического явления у студентов инженерно-технических специальностей и направлений

The ability of young specialists to quickly adapt to production and emerge into the general engineering process is one of the main requirements of employers for graduates of the higher educational institutions today in the development of modern society. In the higher technical school there is stated the urgency of raising the level of education in order to find the most optimal ways of improving the quality of acquiring fundamental knowledge, practical skills and abilities necessary the future graduates in their professional activities, which is regulated in the new Federal State Educational Standards. It has been found necessary to set a goal of organizing the educational process, the main component of which would be the professionally oriented activity of students. Then it becomes obvious that the process of perception is directly related to the developing the reality, accumulation and comprehension of data obtained during the interaction of the student with the environment. In accordance with generally accepted ideas in the scientific world, which correlate with the epistemological concept of cognizability of the world, the knowledge acquired by a person must undergo a test in the realities of practical activity. Based on the experience of working in the higher education system, it has been inferred that for students of a higher technical school it is especially important not only to test the theoretical knowledge gained by experience, but also to gain new knowledge in the learning process based on experimental data and possible further application of gained experience in professionally oriented activities.