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Dynamic Tests on a Series Wound DC Motor. Simulation of the Braking of the Vehicle Driven by the Motor
15-20Views:222In the following we present the role and contribution of vehicle dynamics simulation to vehicle development in the University of Debrecen Faculty of Engineering. We present the input technical parameters which are necessary for the simulation of the series wound DC motor – which drives the vehicle – and also the procedure for their measurement together with the results of dynamic test measurements on the motor. The latest version of our vehicle dynamics simulation program –which is capable of the simulation of braking too – is also presented here.
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Comparative Study of Surface Treatment Procedures for Dental Implants
12-32Views:328Nowadays, the most common type of implant in dentistry is a partial tooth replacement, such as a crown, or a complete tooth replacement. Today, many manufacturers offer implants made of a wide variety of materials and designs. These restorations must meet strict standards, one of the most stringent being surface roughness. Since proper bone-to-implant contact only occurs with adequate surface roughness, several methods are used to achieve the correct value. After reviewing the results of experiments carried out by several research groups, it is concluded that the surface roughness, the shape of the implant fixation screw, the shape of the thread and the thread elevation used to achieve the desired roughness together determine the success of the implantation. The average surface roughness required for osseointegration is considered to be optimal for values between 1 and 100 µm. In most cases, the surface roughness of commercially available dental prostheses is Ra 1-2 µm, but this can be modified by various grinding, acid etching and polishing processes to suit the application. Acid etching is a common technique for roughness reduction, which is the most effective in reducing surface roughness of dental restorative materials (mostly titanium alloys), thus bringing the roughness within the desired range. The result of acid etching is influenced by the concentration of acid, the temperature of the acid bath and the time spent in the acid. The acid used for the surface treatment is important and is most commonly sulphuric acid, hydrochloric acid or hydrogen fluoride (HF) and combinations of these. The study shows that the most optimal results are obtained with HF. Replacements are nowadays largely made by additive manufacturing, which allows for customised replacements and, due to dimensional accuracy, reduces the time and cost of post-processing, i.e. the surface treatment can be used to achieve the desired surface roughness and size at the same time. As a result, newer materials are being used for clinical prostheses and surface treatment should be applicable to all materials. The most optimal solution is a combination of grit blasting and acid etching. With this technology, the surface roughness for all materials reaches the optimum value of 1-100 µm, sometimes 1-2 µm, but can be further reduced below 1 µm by polishing. The study investigates the role of surface roughness, the surface roughness should only be reduced up to a certain value, approximately 0.5 µm, as smooth surfaces have limited or no potential for osseointegration.
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Full-Scale Tests of Pipeline Girth Welds Under Complex Cyclic Internal Pressure and Static Bending Loading Conditions
76-82Views:303The critical elements of high-pressure hydrocarbon transporting pipelines are often the girth welds, which are subjected to complex loads. The aims of our research and this paper are to introduce our full-scale pipeline fatigue and burst tests applying cyclic internal pressure and superimposed external bending stress on girth welds, furthermore, attracting the importance and the applicability of the investigation results. A unique testing system was built to study the behaviour of pipeline girth welds under simultaneous loads. The tests were evaluated using video camera recordings, internal pressure vs. burst time functions and failure pressure values.
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Stationary and mobile particulate matter concentration measurement in Miskolc
338-344Views:271A stationary and mobile device based on a low-cost dust sensor (Plantower PMS7003) was used to study particulate matter (PM) concentration in Miskolc. The stationary device was placed at the automatic monitoring station of the National Air Quality Measurement Network (OLM) in Martintelep, Miskolc. The mobile device was used to walk 4 streets along a square route with a total length of 800 m. Measurements were made on two days (September 9 and 11) between 7am and 9am, which according to preliminary experience coincided with the morning rush hour. The access route includes the OLM monitoring station, a busy road, two bypasses, a parking lot, and a smaller roadway blocked by traffic. The measured PM1, PM2.5, PM10 concentrations of the mobile device were interpolated on a circuit-by-circuit basis in ArcGIS, and conclusions were drawn for the area. The concentration of stationary and mobile devices was compared.
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The Future of AI-Integrated Project Management: A Structured Literature Review Based Risk Identification
42-67Views:527The evolution of AI is changing the landscape of project management. The integration of AI into project management brings many advantages, yet it is also accompanied by prominent weaknesses and serious challenges. In addition, rapidly evolving technologies continue to transform the field’s dynamics. These evolving dynamics result in ambiguity about the current state of the field, and consequently, create an uncertainty regarding a roadmap for future advancements. The purpose of this paper is to address this challenge by developing a well-grounded conceptual insight that identifies the risks associated with AI adoption in project management, guiding both academia and industry towards a structured approach to its future advancements. This paper conducts a detailed structured literature review, adhering the PRISMA protocol, to evaluate the impact of AI on key facets of project management, its potential benefits and implementation challenges. Then it analyzes the literature and synthesizes the key findings. Finally, it conducts comprehensive analysis to identify both positive and negative risks i.e. opportunities and threats. This in-depth analysis and its findings enable us to understand the nature of the risks, and how those can be harnessed or mitigated to advance the field. Furthermore, it provides both academia and industry the foundation to plan improved risk mitigation strategies and to develop a structured adoption framework. This study is expected to make a significant contribution to the advancement of the field.
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Examination of the Physical Activity of Amateur and Hobby E-sport Players
Views:653With the spread of computers and the Internet, e-sports became a fast and dynamic growing sector with a significant market and economic potential. Its importance is demonstrated by the fact that its growth is now outstripping some traditional sports or other industries. E-sports users are sedentary in front of a computer during both competition and training, so their health is determined by the amount of physical activity they do when they are not in front of a computer. The primary aim of this research is to investigate the physical activity of e-sports users at different levels. In addition to this, I considered it important to investigate what games the players I interviewed compete in, how much time they spend playing and how they improve their skills. I conducted an online questionnaire survey in the University Electronic Games (UEG) online tournaments organised by the University of Debrecen. The participants in the survey fully met my criteria, as most of them were amateur or hobby e-sports players, so I obtained relevant data from their answers. Based on the participants' responses, it can generally be said that they engage in health-enhancing physical activity. However, it should be remembered that not only the rise in popularity of e-sports, but also the increasing digitalisation of society is contributing to the rise in sedentary lifestyles. In the future, it would be important to change the way gamers exercise, which until now has been predominantly to develop their digital video game skills. Physical activity and other health-related behaviours need to be integrated into the training routines of gamers - e-sports players, so that playing sports could become a natural pastime alongside e-sports.
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Developing a Financial Sustainability Model of the Performance Indicators Applied by Jordan Water Company (Miyahuna)
75-87Views:477Jordan is now facing real challenges to satisfy the current population water needs due to limited resources. Moreover, unfortunately, as a result of the increased demand for water in developing countries, water resources become scarce, thus, the sustainable management of water resources is very important everywhere and especially in these areas. The Ministry of Water and Irrigation in Jordan is aiming to improve both its quality of service and financial sustainability, therefore, it started to apply the performance measurement system developed by the International Water Association (IWA) to monitor its performance towards achieving these goals. In this article, a model connecting a financial sustainability indicator (operating cost coverage ratio) with other performance indicators applied by the ministry is developed. To assess the performance indicators and to build the model secondary data are collected from the targeted company, the data are analyzed using SPSS and Excel computer programs. Non-revenue water (NRW), speed of repair of bursts, and training per employee are found to be the indicators that have a major impact on Miyahuna’s financial sustainability, the NRW is found to have a negative relationship with the financial sustainability, whereas the other two indicators have a positive relationship. As a conclusion, reducing the NRW and increasing both the speed of repair and training per employee are recommended, by applying some methods that continuously diagnose problems in the water systems and defining clear and strict policies to control the water theft. Furthermore, using Active Leakage Control (ALC) methods, providing the needed equipment, tools and resources, and adopting new methods for training.
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Economic Effect of the Coronavirus on the Companies Involved in Car and Automotive Parts Trading, and Manufacture of Tires of Hungary, Including Szabolcs-Szatmár-Bereg County, in Respect of 2020
1-12Views:458In Hungary the wake of the first wave of the Covid-19 epidemic (March 2020), caused a decline in demand for goods and services in most sectors. There were sectors (accommodation services, art, recreation, etc.), which were economically severely burdened by the imposition of restrictive measures, and there were some (financial services, communication), which experienced the change positively. In our research, our goal was to assess the changes caused by the Covid-19 epidemic in the property, financial and profitability situation of the companies involved in car and automotive parts trading, and tire manufacturing, in Hungary, and within the country, in Szabolcs-Szatmár-Bereg county. We established three hypotheses: (1) As a result of the spread of coronavirus epidemic, in Hungary and in Szabolcs-Szatmár-Bereg county as well, the profitability of companies of NAICS codes 441 (car and automotive parts trading) and 4231 (wholesale of road vehicles and parts), decreased. (2) The outbreak of the epidemic had a negative impact on the liquidity of companies established in Hungary, including Szabolcs- Szatmár-Bereg county. (3) As a result of the Covid-19 epidemic, the resource structure of Szabolcs-Szatmár-Bereg county companies, analysed in the framework of research work, transformed. To prove or disprove these, secondary research was used. Finally, we put forward conclusions and proposals for the management of the companies active in this industry.
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Design of Experiments Application for Machining Process Analyse
257-265Views:245In this contribution are results from machining of the aluminium alloy by spiral router. The experiment was designed as full 3 - factors and 2-levels process and for evaluation of input factors to output parameters – Fx and Fy components were used Paret´s diagram and Lorentz´s line. The input parameters were: revolution speed (4000/min. and 6000/min.), working engagement of a cutting edge (depth of cut) ae (1 mm and 3 mm), back engagement of a cutting edge (with of cut) ap (5 mm and 15 mm) and down (climb) milling.
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Speed Variation along an Imposed Linear Trajectory, for Robotic Arms Motion
495-502Views:209The paper describes a method of speed (velocity) computation, named mixt profile, during a motion upon an imposed linear trajectory. The method assures an accurate positioning at the end of motion (movement), in a well determinate time lapse. The described method is linked with position vector computation, about a robotic arm.
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Investigation on Double Oxide Film Initiated Pore Formation in Aluminum Casting Alloys
141-153Views:552The most common, and in fact, the most deleterious defects of aluminum casting alloys are the so-called double oxide films or bifilms, which have a central role in porosity formation, as they can easily unfurl and inflate into pores during the solidification of the alloys. Sr addition is generally used in the foundry industry for the modification of the eutectic Si phase of hypoeutectic Al-Si alloys. However, Sr microalloying usually leads to an increased pore formation tendency. As bifilms are preferred sites for pore formation, it should be expected that Sr additions have a significant effect on the number and/or the structure of double oxide films present in the melt. In this work, the relationship between Sr-concentration and the susceptibility to pore formation has been investigated through the evaluation of melt quality of melts which had different levels of Sr. The bifilm content of the melts was investigated by the analysis of K-mold specimens and X-ray computed tomography (CT) of reduced pressure test (RPT) samples. It was found that liquid alloys with a higher Sr concentration had a significantly greater tendency to pore formation, which can be explained by the presence of a larger number of bifilm defects in the liquid alloy.
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Segmenting the Impact of Organizational Structure and Leadership on Project Resilient and Project Success in the Ethiopian Construction Industry: a FIMIX-PLS & PLS-POS Approach
73-103Views:308This research looks at the vital roles of leadership and organisation design in the attainment of project resilience and success in the construction sector. Informed by contemporary theories on organisational resilience and leadership, a framework was developed and rigorously tested against data using Partial Least Squares Structural Equation Modelling (PLS-SEM) and with more advanced techniques of segmentation (FIMIX-PLS and PLS-POS) to identify and take into consideration unobserved heterogeneity. Using data collected from project professionals, resilient leadership and adaptive organisation design were shown to be critical to project resilience, but the effect of leadership and organisation design on project resilience differed from segment to segment as well as across demographics. The ex-post analysis suggested that the awareness of resilience, practical experience and higher education exacerbated the relationships between aspects of resilient leadership and project resilience, as well as between adaptive organisation design and project resilience. The analysis also showed that relationships between leadership, organisational structure, and resilience can be mediated by demographic factors, such as awareness, experience, and education. The findings highlighted the importance of fostering inclusive, participative type leadership styles and continuous forms of experiential learning to enhance resilience outcomes. The value of specific indicators such as team participation in decision making or the leader's self-confidence was also identified as being critical aspects of resilient organisational structures and effective leadership. The implications of this study were important for each group of stakeholders: organisations should encourage resilience-based leadership, experiment with multi-dimensional flexible team structures and create a culture of continued, experiential learning and communications as knowledge and industries evolve. The theoretical contributions that validated the effects of segments of latent variables and offered insight into the added value of using segmentation were positive contributions to theory. Limitations, such as sample size and sector, stimulate avenues for future work and in particular reinforce the case for longitudinal, cross-sector research to build sectors’ internal and external constructs of project resilience. Future research needs to apply multi-facilitated empirical, qualitative and advanced analytics means to enable further quantification, and complexity in project survival, success and resilience.
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The Role Of Leader In Work Addiction
85-97Views:451Over-attachment to work is an increasingly common phenomenon in the lives of people in organisations, and can also be a condition of work addiction. Whoever becomes involved in an organisation, be it a subordinate or even a manager, work addiction has a number of negative consequences at both individual and organisational level. Without being exhaustive, work addiction can have an impact on organisational performance, organisational effectiveness, workplace conflict, career prospects, health maintenance. In this paper, we aim to highlight the most relevant publications from the last five years to report on the impact in an organisation when work addiction arises among subordinates or managers, and how different leadership styles are associated with work addiction among organisational members. The publications were retrieved from Google Scholar and Scopus, and the results of 19 articles are presented in this paper after a review of 263 papers retrieved. The results show that transformational, servant and ethical leadership styles have ambiguous effects on work addiction, unlike laissez-faire or abusive leadership styles, the former enhancing and the latter reducing the incidence of work addiction in an organisation. Work addiction of managers also has a dual effect: on the one hand, it can enhance creativity, but it can also increase turnover among subordinates. Social support from the manager can be an antidote to subordinates' work addiction, but this effect may be modified by the quantity and quality of interaction between manager and subordinate, the sense of meaningfulness of the work, or even the organisational culture. Overall, the manager, as a key actor, can have an impact on work addiction in the organisation, but there is not always a consistent position in the research on the cases and the way in which this is done, which calls for further research in the future.
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Efficiency of the Machining Process of Circular Shapes by Electrical Discharge Technology
53-61Views:317Due to its high machining precision, EDM technology is nowadays very important in the production of high-precision parts for various industries. The high precision of the machined surface in combination with the ability to machine circular surfaces brings, in addition to several advantages, some negatives. The most significant negative of this machining technology is the relatively low productivity as well as the overall production efficiency. The latter is affected by many accompanying phenomena. The main accompanying phenomenon that contributes to the decline in the overall economic efficiency of EDM is the microgeometry errors that occur due to the non-homogeneity of the EDM process. Another accompanying negative phenomenon is the geometric accuracy errors of the machined surface, as a consequence of systematic destruction of the wire tool electrode, faulty interpolation in its guidance, and, last but not least, its vibration. These aspects consequently lead to the requirement for multiple applications of additional finishing cuts, which significantly reduces the overall economic efficiency of the machining process. Therefore, the experimental research aimed to search for options that can effectively help to achieve higher productivity but especially the overall economic efficiency of the machining process.
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Enhancing Customer Experience in Car Servicing: Insights from Indian Markets
113-123Views:267This descriptive research has attempted to assess customers' satisfaction with services offered by car servicing firms in India. The researcher administered a structured questionnaire to 300 company customers, selected using the Systematic Random Sampling technique. Data collected were analyzed using SPSS, applying the analytical tools of Frequency, Percentage, Mean, factor analysis, cluster analysis, Chi-square and Correspondence Analysis. Results of the study have revealed that the caring nature of servicing staff, the quality of services and service personnel, and the convenience and comfort offered to customers have been identified as the most important factors affecting customer satisfaction.
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Investigating the Impact of Nature in Designing Cultural Environments for Children
244-256Views:350There is a tendency to communicate with nature in human beings as a set of emotional experiences. This study investigates the impact of organic architecture in creating cultural spaces for children. The concepts of nature, naturalist architecture and children educational psychology, from the perspective of scholars and researchers in this area are investigated. The children’s perception of nature and their feelings were assessed and one hundred forty respondents among the instructors of cultural centres in different regions of Tehran have answered the questionnaires. To investigate the hypotheses, Univariate T - test and F - test were applied. The results showed that the stimulation of the natural environment has a positive and meaningful effect on curiosity, participation, and fantasy in children, while they show their impressions of nature indirectly. Therefore, designing applicable spaces according to children’s physics, using appropriate colours and furniture as well as more environmentally-related spaces, can have positive effects on social participation, intuitive and verbal skills of the children.
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Adaptability of Powdered Activated Carbon Production from Ground Catering Waste Pyrolysis Coke
162-171Views:294Three mixture of catering waste was pyrolyzed at 650, 725 and 900 °C and the solid residue (coke) was examined for powdered activated carbon production. For this, the carbon content, iodine number, particle size distribution and scanning electron microscopic images were analysed. Based on the carbon content, these cokes are suitable for activated carbon production, which were 60-85 wt.% (depending on the base material and pyrolysis temperature). The studied cokes showed slightly porous structure with smooth surfaces. Because of this, the iodine number was mostly small (13-30). Based on the grinding experiments, 10 minutes of grinding was found to be optimal. After this grinding time, the reached iodine number of powdered activated carbon was 350-610.
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Advancing Sustainable Waste Management through National Recycling Rate under SDG 12.5.1
61-72Views:488Solid waste management remains a pressing environmental challenge in both developed and developing nations. Recycling has been promoted globally as a key pathway to sustainability, yet recycling rates often provide only a partial picture of performance. In many contexts, challenges such as poorly regulated recycling policies, informal sector dominance, and practices that prioritize profit over environmental sustainability limit progress towards Sustainable Development Goal (SDG) 12.5.1, which tracks the national recycling rate. This study investigates the extent to which recycling rates reflect sustainable waste management and identifies the underlying factors that influence their effectiveness. The major objective of this study is to evaluate recycling rates as an indicator of sustainable waste management. This is further specified by: (i) examining recycling practices in selected countries (Germany, South Korea, USA, Brazil, and India), (ii) identifying key drivers and barriers that influence recycling performance, and (iii) assessing the implications of recycling rates for sustainable waste management systems. The study employed a mixed-methods approach, combining secondary data analysis, comparative country assessment, and policy review. Results show that recycling rates are useful but insufficient as a stand-alone measure of sustainability, since they are influenced by broader elements such as policy enforcement, economic incentives, public participation, and market structures. The findings highlight that Nigeria’s recycling rate remains significantly low compared to leading economies, underscoring the need for integrated waste management reforms. This research contributes to environmental management discourse by demonstrating that while recycling rates provide a benchmark for SDG 12.5.1 monitoring, they must be interpreted alongside contextual drivers to ensure meaningful progress towards sustainable waste management.
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Sustainable Energy in Aviation with Reverse FMEA Analyses
29-40Views:386This research aims to identify and evaluate the key challenges and obstacles hindering the adoption of sustainable energy in the aviation industry. The outcomes and insights derived from this research will be synthesized to provide a comprehensive overview of the opportunities and suggestions for the adoption of sustainable energy in the aviation industry. The objective of this study is to help the aviation industry’s shift toward more sustainable energy sources in order to reduce its environmental footprint and mitigate the effects of climate change.
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Potentiodynamic Study of the Effects of Nickel on The Electrodeposition of Zinc from Chloride Media
15-24Views:302Abstract. The potentiodynamic experiments of the nickel effects on the zinc electrodeposition have been done to understand the impact of Ni impurities on the electrowinning of Zn from spent pickling liquor. The nickel chloride solutions of Ni concentrations 90 and 1 g/dm3 were used as the electrolytes. The latter was also mixed with 90 g/dm3 Zn in the experiments. All the runs were carried out at room temperature with 40 mV/s continuous polarization speed and with 1/s sampling rate. It was observed that nickel electrodeposition from chloride media containing 90 g/dm3 Ni started with the generation of hydrogen bubbles, entirely blocking the cathode surface. Only a slight current development was observed until the polarization potential ~ -0,8 V. The visual observation showed bubbles also formed at the anode, which may represent chlorine and/or oxygen evolution. While, in the electrodeposition of nickel with only 1 g/dm3 Ni concentration in the electrolyte, metal deposition was hardly observed, but visible hydrogen bubbles constantly blocked the cathode surface. A similar tendency was observed in the mixed-solution electrolysis cell; the initial tiny bubbles accumulated at the cathode surface more than in the pure Zn solution. The enhancement of H2 evolution indicates how nickel deposition may contribute to the loss of useful current in the process of Zn electrodeposition. The mass of nickel deposited from the mixed solutions significantly decreases as the Ni concentration decreases in the electrolyte, while the mass of deposited zinc is relatively constant. It means that the purity of the produced Zn is appreciably higher – with respect to Ni – if nickel is efficiently eliminated from the solution before electrowinning.
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The Impact of labor Turnover on The Service Quality of Hotels
98-105Views:598This study aimed to know the dimensions of labor turnover (low morale, poor employees training, payment, job satisfaction) and study the effect of these dimensions on the quality of service in hotels. The results of multiple regression show that there is an effect of dimensions labor turnover on quality of service. Correlation between labor turnover and tangibility was the strongest and there is a moderate relationship between labor turnover and each of responsibility, reliability, assurance, and empathy.
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Structural Investigation of Granular Composites by Modern Methods
179-185Views:291Structural investigations of polymer-based particulate composites were carried out using modern test methods. We had composite sheets with different compositions and different injection molding speeds. In the polypropylene matrix, three types of glass beads were mixed in three weight percentages. In our investigations, the granular composites were studied with a widely used examination equipment, scanning electron microscope (SEM) and industrial computer tomography (CT) as a modern diagnostic tools. The purpose of the study was to investigate the distribution and interfacial adhesion of glass beads.
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Advancing Maintenance 4.0 through an Asset Management Framework: a South African Petrochemical Industry Case Study
1-20Views:159The rapid advancement of digital technologies has raised uncertainty about the adequacy of traditional maintenance models to meet Industry 4.0 requirements. This study develops and validates an asset management framework to support the South African petrochemical industry’s transition to Maintenance 4.0. The framework was validated through a quantitative survey conducted within a leading petrochemical company in South Africa, ensuring its practical applicability. Descriptive statistical analysis confirmed 15 of 17 framework characteristics and supported five of seven theoretical propositions. Key enablers of Maintenance 4.0 adoption include the integration of human intelligence, machine learning, and real-time data, as well as the role of organizational culture and asset resilience in shaping outcomes. The study offers both theoretical contributions and practical guidance for maintenance professionals seeking to align maintenance practices with Industry 4.0 principles, with relevance extending beyond the immediate case context.
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The Dynamic Effect of Trade Openness, Debt, and Foreign Investment in Ghana’s Economy: An ARDL Bound Testing Approach
94-112Views:447The impact of macroeconomic factors offers insight into the performance of an economy. This study investigates the dynamic short- and long-term effect of trade openness, external debt, and foreign direct investment (FDI) within Ghana's economy. Utilizing Autoregressive Distributed Lag (ARDL) bound testing and Granger causality analysis, the study examines data spanning from 1991 to 2022. The results of the ARDL cointegration test reveal a long-term relationship among the variables. However, in the short term, the findings present a mixed effect of FDI and trade openness, with both positive and negative impacts. In the long run, FDI and external debt exhibit a positive influence, whereas trade openness appears to impede economic growth. Furthermore, the Granger causality test identifies a unidirectional causality relationship between the variables and economic growth. The study suggests that the government implement investment-oriented and trade policies to stimulate economic growth.
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The Effect of Fluxes on the Melt Quality of AlSi7MgCu Alloy
372-380Views:334The presence of inclusions such as oxides, carbides or refractory particles can be harmful to the mechanical and surface characteristics of castings. Inclusion-rich metals result in lower fluidity and feeding capability during casting. Nowadays, solid fluxes are widely used in foundries in order to reduce the inclusion content of aluminium melts. In this study, the effect of four different fluxes on the melt quality was studied. First, the inclusion content of the flux-treated melt, and then the properties of the fluxes (i.e. chemical composition and melting temperature) were examined.
