Permanent Connection Research Articles

Submerged arc welding process: enhancement of production performance based on metallurgical observations

Welding processes are widely used technologies in the industrial context for creating permanent connections between mechanical components. This popularity is due to their versatility, which arises from the numerous available process variants and the multiple advantages they offer compared to other joining techniques. In the manufacturing context, where devices often operate in extreme conditions, the quality of welds becomes a critical factor in ensuring the safety and reliability of the manufactured products. Furthermore, a sound joint requires careful compliance with the increasingly stringent design specifications demanded by customers who require industry-standard conformity in order to achieve defect-free, robust, and durable welds. To address these needs and to define the optimal roadmap for the investigated process condition, an experimental investigation was conducted on the submerged arc welding process. The experimental trials involved butt joints of ASTM A516 Gr.70 carbon steel plates with different thicknesses in a flat position, utilizing a U-shaped chamfer and a multi-pass welding technique. For each weldment, the effects of the main process parameters on the qualitative characteristics of the manufactured products were evaluated from a metallurgical perspective. This evaluation included an in-depth metallographic analysis of the heat-affected zone of the carbon steel joint and involved both the measurement of the dimensions of these areas as well as the amount of ferrite and pearlite that resulted as the phases observed in the final microstructure of the steel joint following its solidification. Furthermore, the joint quality was assessed with regard to mechanical strength through hardness measurements. By analysing the experimental data, the paper provides a valuable contribution for increasing the productivity of the investigated welding process, while simultaneously meeting the specified industrial quality requirements for the products made of medium-thickness carbon steels.

Structure and Strength of a Permanent Connection between Stringer and Skin Formed by Direct Sequential Growth from Aluminum Alloy

Structure and Strength of a Permanent Connection between Stringer and Skin Formed by Direct Sequential Growth from Aluminum Alloy

Wykorzystanie nowych technologii medialnych przez młodzież i seniorów. Raport z badań

The Internet and new media have become an integral part of everyday life for many people, regardless of age or social status. Young people and senior citizens are two important social groups affected by the development of media technologies, although often in very different ways. People belonging to different social categories may use new technologies in significantly different ways and have different problems related to their everyday use. Therefore, the aim of the analysis in the following sections is to identify the characteristics and ways in which young people and seniors use new media technologies. The analyses of the empirical material obtained in the face-to-face interviews aimed to answer the following research questions: (RQ1) What are the ways, characteristics and problems associated with the use of new media technologies by contemporary users? (RQ2) What are the peculiarities of the use of new media technologies by young people? (RQ3) What are the peculiarities of the use of new media technologies by older people? The results of the research indicate that the ways, characteristics and problems of using media technologies are rarely shared between older and younger people, as significant discrepancies are usually revealed. In particular, the observation of the specifics of the use of new media technologies by young people indicates that for them it is a tool that is indispensable for their daily personal, social and educational needs (permanent connection). Seniors, on the other hand, recognise the benefits of technology, but at the same time value life beyond the screen.

Virtual Reality in The University Classroom: Experiences, Challenges and Opportunities For Teaching in Higher Education

Objective: This article aims to explore virtual reality from its experiences, challenges and opportunities for teaching higher education and learning content from different areas of knowledge. Methods: This uses a qualitative approach through a documentary search that allows us to know the implementation of virtual research in the classroom as a significant process for teaching university students. The population involved in the research are studies carried out between 2018 - 2024 and the sample is selected using eligibility criteria; on the one hand, the inclusion criteria determining databases such as Scielo, Redalyc, Dialnet and Google Scholar and Scopus; On the other hand, articles that do not contain the categories of principles such as virtual reality, teaching and university education are excluded. Result: As a result, a total of 25 studies were collected from which a discussion is developed about the challenges, opportunities and learning experiences of RVI; This is essential because it determines an implementation path for university teachers in higher education institutions. Thus, it is concluded that the challenges are infrastructure, permanent network connection and the digital skills of teachers; The opportunities are the motivation and positive attitude of learning, interaction and communication, teamwork and academic progress and finally, the experiences determine a development in the student's knowledge and their ability to apply said knowledge in reality. physics through learning experience in simulated reality.

Assessing the influence of parameters on tissue welding in small bowel end-to-end anastomosis in vitro and in vivo.

The use of high-frequency electric welding technology for intestinal end-to-end anastomosis holds significant promise. Past studies have focused on in vitro, and the safety and efficacy of this technology is uncertain, severely limiting the clinical application of this technology. This study investigates the impact of compression pressure, energy dosage, and duration on anastomotic quality using a homemade anastomosis device in both in vitro and in vivo settings. Two hundred eighty intestines and 5 experimental pigs were used for in vitro and in vivo experiments, respectively. The in vitro experiments were conducted to study the effects of initial pressure (50-400kpa), voltage (40-60V), and time (10-20s) on burst pressure, breaking strength, thermal damage, and histopathological microstructure of the anastomosis. Optimal parameters were then inlaid into a homemade anastomosis and used for in vivo experiments to study the postoperative porcine survival rate and the pathological structure of the tissues at the anastomosis and the characteristics of the collagen fibers. The anastomotic strength was highest when the compression pressure was 250kPa, the voltage was 60V, and the time was 15s. The degree of thermal damage to the surrounding tissues was the lowest. The experimental pigs had no adverse reactions after the operation, and the survival rate was 100%. 30days after the operation, the surgical site healed well, and the tissues at the anastomosis changed from immediate adhesions to permanent connections. High-frequency electric welding technology has a certain degree of safety and effectiveness. It has the potential to replace the stapler anastomosis in future and become the next generation of new anastomosis device.

Experimental investigations of dry-dry timber-concrete composite notched connections designed for disassembly

Timber-Concrete Composite (TCC) decks offer an efficient, and environmentally friendly alternative to conventional concrete slabs. Traditionally the concrete is cast directly onto the timber with a permanent connection arrangement that does not allow non-destructive disassembly at end-of-service-life. This will prevent the reuse of the materials and ultimately decrease the extent of the environmental benefit. This paper presents a deconstructable dry-dry notched connection made from fully prefabricated timber and concrete elements. The concept was investigated through 30 experimental pure-shear push-off tests, where various design parameters, such as prestressing degree, fastener placement, and notch length, were varied. The experimental results indicate that the new connection exhibits the same stiffness characteristics as a traditional wet-dry notched connection. Five different failure modes were observed in the series, and experimental measurements such as Digital Image Correlation and fastener force measurement provided insight into the connection behavior during failure. Two rigid-plastic upper bound solutions were established to estimate the load-carrying capacity for two of the observed concrete failures, and a satisfactory agreement with the test results was obtained. In conclusion, the experimental results indicated that dry-dry notched connections are feasible for achieving a more environmentally friendly TCC structure.

Mechanical Properties of Furniture Joints Using Loose Tenons and Connectors

The investigation conducted in this study focused on assessing the withdrawal resistance of T-joints and the bending moment capacity in the tension and compression of corner joints. For samples, preparation glued-in loose tenons (Domino dowels) and dismountable connectors were used as connecting elements. The joints were made of European beech wood and a D3-grade PVAc adhesive was utilized for bonding. The effect of the joint type, the shoulders’ bonding, and the load application direction were investigated. The test results revealed that the withdrawal resistance of Domino dowel joints exhibited twice the strength compared to Domino connectors. Moreover, the presence of a bonded area on the shoulders did not significantly impact the strength of the joints. In the case of corner joints, the bending moment capacity in compression was notably influenced by the bond line on the shoulders, although such an effect was not significant in tension. Domino dowel joints provided a robust and reliable permanent connection between wooden elements, surpassing Domino connectors; however, in both cases, the strength values exceeded those of conventional dowels and cam lock connector joints.

Digital Entrepreneurship: An empirical Approach on Students’ Perceptions and Attitudes

Digital transformation, as a new reality, conducted to significant changes in entrepreneurship and determined the development of a new area in the market process, namely digital entrepreneurial activities. In this context, the main purpose of the research is to provide a spotlight on students’ perceptions and attitudes toward digital entrepreneurship, by using a structural equation modelling. The survey responses were processed by using Smart PLS 4 statistical software and the empirical endeavour was designed in line with the research objectives for testing 12 hypotheses. 10 out of 12 hypotheses were confirmed, excepting that ones that analyse the relationship between motivation and attitudes and between motivation and digital entrepreneurship. In the particular case of the selected sample, the variance of digital entrepreneurship variable is 64.40% explained by the proposed model. Consequently, the findings argue a general trend in using the ICT tools for the entrepreneurial intention, but also the permanent connection between digital entrepreneurship and skills, attitudes, perceptions, motivation and educational background.

Тема бессмертия души в философии Плифона (с приложением перевода его надгробных слов Клеопе Малатесте и Елене Палеологине)

Introduction. The article examines the views of the last major Byzantine philosopher George Gemistos Plethon on the immortality of the human soul. Scholars are still debating whether Plethon was a pagan who completely rejected Christianity, or a Christian who was too fond of Platonism. Methods. Methods employed in this article are source research, information analysis, comparative research. Sources on the subject include: Plethon’s funeral orations on Cleopa Malatesta and on Helena Palaiologina, “Book of Laws”, commentaries on the Chaldean Oracles, “On the Differences of Aristotle from Plato”, “Summary of the Doctrines of Zoroaster and Plato”, “Áddress to the Despot Theodore on the Peloponnese”, Theodore Metochites’ treatise “On Education”. Analysis. An analysis of Plethon’s writings shows that in his doctrine of the human soul and its posthumous destiny Gemistos was far removed from Christianity. Plethon confessed the pre-existence of souls to bodies and metempsychosis, he considered life in body as the main human mission in universe, as a link and boundary between the mortal and immortal worlds. According to Plethon, permanent periodical connection of immortal and mortal (soul and body) in human is better, than endless immortality after one life. His doctrine about soul does not imply neither deification of body, nor bodily resurrection and terrible judgment at the end of time. Results. In Plethon’s monodies, his non-Christian views are expressed in a veiled way, but a careful analysis of the text of the monodies in comparison with the other works of the philosopher shows that his views on the destiny of the soul, on the one hand, were very different from those of the Christian Church, and on the other hand, they looked more optimistic, leaving the soul the opportunity both for gradual improvement in a series of rebirths, and for enjoying the divine life between them, subject to virtuous behavior on earth. Appendix. The article is accompanied by a Russian translation of Plethon’s monodies on Cleopa Malatesta and Helena Palaiologina.

Covid-19 Pandemi Sürecinde Hemşirelik Öğrencilerinin Ailelerinin Uzaktan Eğitimle İlgili Görüşleri

Aim: Distance education is an interdisciplinary field that aims to remove the limitation between educator, learner, and learning resources and of uses existing information and communication technologies for this purpose. Maintaining social distance, especially during the pandemic, has been instrumental in protecting and maintaining the health of both students and educators. However, distance education's entry into our lives as a necessity during the pandemic has brought many problems. The fact that the education environment left the classroom and came into the home, and that time shared with family members is now used for education, makes it necessary to conduct studies to determine families' experiences, attitudes, and opinions about distance education. This study aimed at determining families’ opinions of undergraduate and graduate nursing students on distance education during the Covid-19 pandemic. Methods: This is a descriptive and cross-sectional study. The study was conducted with 407 participants. The data were collected between the 9th and 10th months of the pandemic, with the data collection tool developed by the researchers. Results: The families have a negative opinion on distance education, and these opinions were affected by their negative experiences and problems. The families found the low costs and the increased time the students spent with their families to be positive aspects of distance education. The families complained about connection problems, the student spending too much time on the computer and about the home environment needing to be more suitable for education. However, negative opinions of the families included that distance education is insufficient in conveying professional skills and that distance education is not suitable for nursing education. The opinions of Y-generation family members, those with graduate education, and those with a permanent internet connection at home had more positive opinions than the others. Conclusions: Distance education has become an integral part of our lives. Therefore, it is essential to unearth problems regarding distance education and develop solutions. Study results on the opinions, attitudes, and experiences of all distance education stakeholders will contribute to distance education practices.

Microstructures and mechanical properties of powder-filled laser welding joints composed of high-nitrogen steel

In this work, a permanent connection of a high-nitrogen steel plate is achieved by using layer-by-layer powder-filled laser welding of high-nitrogen steel powder, and the stability levels of the welding process, microstructures and mechanical properties are analyzed. Compared with other processes, powder-filled laser welding is smooth without bursts and spatters, and the nitrogen content of the welding seam is obviously improved. The welding seam consists mainly of austenite, with few ferrite and manganese oxides. There is a nitrogen concentration gradient between the inside and the upper part of the melt pool, which leads to nitrogen escape. Laser remelting exacerbates this process, resulting in more severe nitrogen loss in the bottom layer than in the upper layer of the welding seam. The differences in the nitrogen solubilities in austenite and ferrite and the high-nitrogen content in the melt pool are the main reasons for the formation of micropores. Tensile experiments and impact experiments are conducted on the welding joint. The average tensile strength and elongation of the welding joint are 1032.36 MPa and 19.70%, respectively, contributing to 94% and 53.4% of the total values for the base metal. The grain refinement and relatively high nitrogen content are the reasons for the better tensile strength relative to other processes. The average impact energy of the welding joint is 24.68 J, which is approximately 63.74% of the base metal. Pores are the main reason for the reduced impact energy of the welding joint.

Influence of tool geometry on reaction forces and strength of an inseparable joint produced on a prototype stand with the use of jaws

The present article describes a new and innovative method of producing an inseparable joint with the use of expansion jaws. The effect of jaw tool geometry on the reaction forces and ultimate strength of an inseparable joint formed on a prototype stand was analyzed. The results are also compared of joints produced by jaws with single movement method and with complex movement method. The tool responds with bending and pressing one part into the other, which results in their permanent connection. In the tests, differentiation was introduced with regard to the height of the applied force to the collar of the connection pipe. A novelty is also a solution based on a complex, parameterized trajectory of the stamp movement consisting of horizontal and vertical displacements. This paper presents the tests of the joints formed at the stand. The new approach described in this article has resulted in a joint strength increase of approximately 30% using the innovative complex jaw movement of the biaxial clinching process. A joint tensile strength close to 1000 N was achieved.

Расход тепловой энергии на временное отопление законченных вчерне станций метрополитена

Introduction. During construction of underground facilities, architectural, finishing and installation works begin before the completion of the main structures. At that time, there is no permanent heating network connection and therefore temporary heat sources must be used to ensure compliance with the works technology. The lack of specific information about the required capacity of such sources makes it impossible to forecast the financial costs, which is essential for contractors. The purpose of the study is to determine the specific value of heat energy consumption for heating underground stations, construction of which is carried out by open method, depending on different outdoor temperatures, construction completion, depth of station installation, as well as the construction volume of the station. Materials and methods. Heat flows have been calculated by means of mathematical modelling of a stationary thermal regime. Analyses of calculation results and normative data have been performed in accordance with the provisions of probability theory and mathematical statistics. Calculation of coefficients and loads are carried out according to generally accepted equations and laws of heat and mass exchange. Climatic data and material parameters are taken according to current normative documents. Results. The values of specific thermal performance of open-cut metro stations depending on space-planning and design solutions, composition of external envelopes, as well as the stage of construction completion (including the presence or absence of backfill) are calculated. Estimated rate of heat energy consumption for temporary heating of open cut metro station is 3.87 Gcal/(1,000 m 3 · month). Conclusions. Temporary heating norms (amount of heat energy) for open-circuit metro stations have been proposed. Heat costs for ensuring the specified air parameters, referred to a unit volume and required for construction and installation works inside the stations during the heating period, are determined.

Climate change impact on the freshwater balance of quasi-closed lagoons in the North-Western Black Sea coast

Abstract We studied the impact of regional climate changes that have occurred and are expected in the near future on the freshwater balance of quasi-closed lagoons in the North-Western Black Sea region. These lagoons do not have a permanent connection with the sea but are episodically connected to it by artificial channels, straits, or other hydraulic facilities. We used the value of the deficit in their annual freshwater balance as an indicator of vulnerability to climate change for each lagoon. The changes in the multi-year averages of climatic parameters in the North-Western Black Sea region, which determine the components of the water balance and its annual deficit in lagoons, were assessed by observations at hydrometeorological sites and outcomes of the EURO-CORDEX Project for the RCP4.5 and RCP8.5 scenarios. We have found that regional climate changes are resulting in the increasing deficit of annual freshwater balance for all quasi-closed lagoons in the North-Western Black Sea region. Also, climate change can result in excessive shallowing, salinization, and even the complete disappearance of some lagoons due to the lack of or insufficient water exchange with the sea.

Phylogeography and population genetic structure of the cardinal tetra (Paracheirodon axelrodi) in the Orinoco basin and Negro River (Amazon basin): evaluating connectivity and historical patterns of diversification.

The Neotropics contain one of the most diverse assemblages of freshwater fishes worldwide. Part of this diversity is shared between the Orinoco and Amazon basins. These basins have been separated for a long time due to the Vaupes Arch, rising between 10-11 Ma. Today, there is only one permanent connection between the Orinoco and Negro (Amazon) basins, known as the Casiquiare Canal. However, alternative corridors allowing fish dispersion between both basins have been proposed. The cardinal tetra (Paracheirodon axelrodi), the most important fish in the ornamental world market, is distributed in both basins. Here we investigated P. axelrodi phylogeography, population structure, and potential routes of migration and connectivity between the two basins. A total of 468 bp of the mitochondrial gene (COI), 555 bp of the nuclear gene fragment (MYH6), and eight microsatellite loci were analyzed. As a result, we found two major genetic clusters as the most likely scenario (K=2), but they were not discreetly distributed between basins. A gradient of genetic admixture was observed in Cucui and São Gabriel da Cachoeira, between the upper Negro River and the upper Orinoco. Samples from the middle-lower Negro River were highly structured. Cucui (Negro basin) was more similar to the Orinoco than to the rest of the Negro basin populations. However, substructure was also observed by the discriminant analysis, fixation indices and other hierarchichal structure analyses (K=3-6), showing three major geographic clusters: Orinoco, Cucui, and the remaining Negro basin. Unidirectional migration patterns were detected between basins: via Cucui toward Orinoco and via the remaining of the Negro basin toward Orinoco. Results from the Relaxed Random Walk analysis support a very recent origin of this species in the headwater Orinoco basin (Western Guiana Shield, at late Pleistocene) with a later rapid colonization of the remaining Orinoco basin and almost simultaneously the Negro River via Cucui, between 0.115 until about 0.001 Ma. Historical biogeography and population genetic patterns observed here for Cardinal tetra, seem to be better explained by river capture, physical, or ecological barriers than due to the geographic distance.

Detection of Torque Security Problems Based on the Torsion of Side Shafts in Electrified Vehicles

In the case of electric vehicle drives, faults in the drive system or in the traction inverter, which controls the vehicle drive unit, could lead to abrupt and unpredictable motion as well as acceleration of the vehicle. In terms of functional safety, the typically existing, permanent mechanical connection of the drive machine with the drive wheels poses a high safety risk. In particular, unintended motion of the vehicle from a standstill is especially critical due to the high risk of injury to traffic participants. To reduce this risk, appropriate monitoring algorithms can be applied for the rapid detection of faulty operation. A corresponding algorithm for fault detection in the electric drive of a vehicle is presented in this paper. In addition to the description of the algorithms, various driving maneuvers of an electric single-wheel drivetrain are simulated in fault-free and faulty operation on a hardware-in-the-loop test bench. The focus here is on the consideration of driving-off operations.

ТРАНСФОРМАЦИЯ ИНСТИТУТА ГРАЖДАНСТВА В СОВРЕМЕННЫХ УСЛОВИЯХ ГЛОБАЛИЗАЦИИ: СРАВНИТЕЛЬНО-ПРАВОВОЙ АНАЛИЗ

The work is devoted to determining the key trends in the transformation of the constitutional and le-gal institution of citizenship in the current conditions of globalization. A comparative legal analysis of the concept of citizenship, the grounds and procedure for acquiring and depriving citizenship in different countries of the world is carried out. The author's theoretical-methodological and scientific-practical conclusions about the forms and consequences of the influence of globalization processes on the transformation of the institution of citizenship are formulated. It is shown that investment naturalization is a direct consequence of economic globalization and commercialization of political and legal relations on a global scale. It is proved that in addition to financial and economic grounds, dur-ing naturalization, certain requirements must be put forward for the applicant of a political and legal nature, without which it is impossible to create a stable, permanent connection between the individual and the state. The correctness and timeliness of the introduction into the current Russian legislation of a fundamentally new approach to the deprivation of acquired citizenship as a result of a criminal offense provided for by the relevant legal norms is substantiated. The author's conclusions and generalizations are made regarding the place and role of the institution of citizenship in the life of modern society and the state.

Metoga GTAW Welding Joint Strength Study For Aisi 1045 Application Of Milling Tools

The welding process is a permanent connection process for metal materials using heat energy. The GTAW (Gas Tungsten Arc Welding) welding method is carried out on AISI 1045 steel material with a solid round shape, which has the characteristics and properties of the material slightly above low carbon steel. The welding process was carried out based on AWS A5.18 standard specifications, in this study. by varying the welding amperage between 70, 90, and 110 amperes as well as the ER70S-G series electrodes.To check the results of the welding with the amperage variation, perform tensile testing with standard ASTM A-370 testing, hardness testing using the Vickers method with standard ASTM E-92 testing, microstructure inspection, and grain size calculations as a control for the results of the hardness test. The focus of testing and inspection is carried out in three influential areas, namely, areas of weld metal, HAZ (heat-affected zone), and base metal.The results of this study show that for 70 A welding amperage, the tensile test results in all samples breaking in the weld metal area. While welding amperage 90A broke two samples in the weld metal area, welding amperage 110A broke one sample in the weld metal area. For the results of the hardness test at 110 A amperes, the hardness ratio in the weld metal area to the HAZ area shows that the difference in hardness is not too large compared to the two amperes used, so a welding amperage of 110 A can be recommended. While the results of the microstructure examination in the weld metal area were dominated by pearliet and martensite with a little bainite, the hardness results in the weld metal area were harder compared to the HAZ area and base metal. Likewise, the results of grain size calculations using the Heyn method for regions with higher hardness make the grain sizes appear denser and smaller.

Growing out of overconnection: The process of dis/connecting among Norwegian and Portuguese teenagers

Young people struggle with permanent online connection that is associated with their generation. This article looks at teenagers’ affective relationship to connectivity and disconnectivity, and how it is socioculturally influenced by the media, family, and peers. It reports on an interview study with 36 teenagers between 15 and 19 years of age from Norway and Portugal. Our findings evidenced how disconnection may arise out of a latent feeling of “disaffect” generated in the experience of the ambience of connected and platform culture as well as the media; or of the unavailability created by how teenagers spend their leisure time, which is influenced by families’ moral economies. Teenagers have to perform affective labor in managing the different, sometimes contradictory, forces that converge in the experience of connectivity. Managing digital disconnection appears as an individual—but socially produced—moral obligation to self-govern, to which teenagers have unequal conditions.

Debonding quantification in adhesive bonded joints by the inverse finite element method

In the past two decades, the aerospace industry has massively shifted from aluminum-made components to composite materials such as carbon fiber reinforced polymers (CFRP), striving for more fuel efficient and lighter aircrafts. Consequently, traditional joints have been replaced by adhesive bonded interfaces, which are also the most common choice to repair damaged components. Although adhesive bonding is the most efficient choice for permanent connections, it is not free of disadvantages: one of the most common failure modes, the debonding of the two laps, is very problematic to detect and predict in practice. Therefore, frequent inspections must be performed to ensure structural safety, increasing maintenance costs, and lessening the availability of the platforms. The development of innovative sensing technologies has allowed for a close monitoring of structural interfaces, and several structural health monitoring techniques have been proposed to monitor adhesive bonded connections. Sensitivity and correlation between measurements and debonding entity has been demonstrated in the literature: nevertheless, hardly any technique has been proposed and quantitively evaluated to estimate the debonding entity independently of the applied loads, such as misalignment-induced torsion, which is a major confounding influence in the traditional backface strain gauge technique. This paper proposes the inverse finite element method (iFEM) as a load and material independent approach to infer the debonding entity from strain measurements in adhesive-bonded joints. Two approaches to estimate the debonding entity with the iFEM are compared on cracked leap shear specimens representative of CFRP repair patches: one is based on anomaly indexes, the other on performing a model selection with multiple iFEM models including different damages. The latter demonstrates satisfactory performances; thus, it is considered a significant scientific advancement in this field.