Vilnius Gediminas Technical University
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Effect of Yttrium and Rhenium Ion Implantation on the Performance of Nitride Ceramic Cutting Tools
No full textIn the paper, the results of experimental investigations of ion implanted cutting tools performance are presented. The tools, made out of Si3N4 with additives typically used for turning of Ti-6Al-4V alloy, underwent implantation with ions of yttrium (Y+) and rhenium (Re+) using the metal vapor vacuum arc method. Distribution of ions on the tool surface was measured. The cutting tools were tested in turning process with measurement of cutting forces and analysis of wear. A rather unexpected result was the increased wear of the tool after Y+ implantation with 1 × 1017 ion/cm2. It was demonstrated, however, that the tool after Y+ 2 × 1017 ion/cm2 ion implantation provided the best machining performance.This article belongs to the Special Issue Machinability of Metallic Materials and CompositesThe researches were performed with financial support of Polish Ministry of Science and Higher
Education for UTH Radom, project No. 3257/22/P, and co-funded from the ’Excellent science’ program of the
Polish Ministry of Science and Higher Education as a part of the contract No. DNK/SP/465641/2020 "The role of
the agricultural engineering and environmental engineering in the sustainable agriculture development.
Įmonių konkurencinio bendradarbiavimo modeliavimas
No full textIn the recent years co-opetition has emerged as a new theoretical concept, emphasizing the concurrency of competition and cooperation in business relationships. It is considered as an integrative bridge between older contributions which one-sidedly emphasize either competition or cooperation. However, the co-opetition theory is barely applicable for problems of relationships between enterprises because of structural and methodical flaws. Therefore a framework for the modelling of enterprise co-opetition is introduced. A definition for the term co-opetition and determinants of co-opetition models are introduced, which are external institutions, several industrial boundaries and time. An industrial supply chain is introduced as one of the industrial boundaries in co-opetition models that considers the impact of potential participants and distinguishes between individual customers and mass markets. A profit distribution rule is introduced for supply chains with individual customers, which considers the impact of excluded suppliers and can be used for the prediction of the outcome of auctions. It is shown for both mass markets and individual customers in how far stable agreements can be achieved, facing the problem of ubiquitous time- inconsistency of agreements. It is shown in which cases the introduced profit distribution rule recommends more stable negotiation outcomes than the Aumann-Drèze-rule and the Myerson-rule for coalition structures. Ideal-typical cases of industrial supply chains with mass markets and individual customers are simulated with the software “MATLAB”. Experiments are implemented with test persons via the internet with the software “z-tree”. These experiments are intended to verify the theoretical predictions about the negotiation outcomes and the agreement stability.Doctoral dissertatio
Identification of Road-Surface Type Using Deep Neural Networks for Friction Coefficient Estimation
No full textNowadays, vehicles have advanced driver-assistance systems which help to improve vehicle safety and save the lives of drivers, passengers and pedestrians. Identification of the road-surface type and condition in real time using a video image sensor, can increase the effectiveness of such systems significantly, especially when adapting it for braking and stability-related solutions. This paper contributes to the development of the new efficient engineering solution aimed at improving vehicle dynamics control via the anti-lock braking system (ABS) by estimating friction coefficient using video data. The experimental research on three different road surface types in dry and wet conditions has been carried out and braking performance was established with a car mathematical model (MM). Testing of a deep neural networks (DNN)-based road-surface and conditions classification algorithm revealed that this is the most promising approach for this task. The research has shown that the proposed solution increases the performance of ABS with a rule-based control strategy.This article belongs to the Special Issue Advance in Sensors and Sensing Systems for Driving and Transportatio
Impact of Investment Sources for Sustainability on a Country’s Sustainable Development: Evidence from the EU
No full textAll countries face several issues while running the process of sustainable development—the absence of a uniform means of sourcing investment for sustainable development and the lack of a unified index for the evaluation of sustainable development. No doubt, ensuring sustainable development requires constant financial investments. Hence, it is essential to examine the investment sources for sustainable development at the country level and to comprehend if the current financial investment has a direct impact on the results of a country’s sustainable development. The article aims at identifying the financing sources for sustainable development for each of the European Union (EU) countries and assessing their impact on each of the EU countries’ sustainable development, which is expressed as the Integrated Sustainable Development Index (ISDI). After the detailed analysis of investment sources for the sustainability of the EU countries, two sources of investment, assignation of budget and the EU structural funds, were selected, and ISDI calculation was applied for twenty-five of the EU member states for the period 2003–2017. Correlation analysis (using SPSS software) helped to identify the strength of the connection and to select countries for the Johansen Cointegration Test (using Eviews software) in order to determine how variables interact. The results show that the combination of the assignation of budget and the EU structural funds has a positive impact on the coherence of five (Czech Republic, Denmark, Spain, Slovenia, and Austria) out of twenty-four countries.This article belongs to the Special Issue Sustainable Investment and Financ
Investigation of Roller-Tape Contact Pair Used in Precision Mechatronic System
No full textSmoothness of tape movement and stability of the tape area where elements are generated are very important in precision mechatronic devices where precise elements are generated on a steel tape, controlling them in real time. During movement, deformations and vibrations form in the steel tape area where elements are generated as a result of imperfections of movement equipment, contact between the roller surface and the tape, and errors arising in the movement process. This article is based on the need for a detailed theoretical and experimental research of the effects occurring during the movement of the precision steel tape used in measuring systems with precision elements generated on the tape, including an investigation of the roller-tape contact. The article also aims to develop a model of the system for measuring the displacement of the tape in a raster formation device, to investigate and assess possible effects of external and internal factors on steel tape parameters. The article presents experimental research conducted for determining dynamic variables forming during the movement of a steel tape, assessing the factors that may cause raster generation errors in dynamic mode.This article belongs to the Special Issue Systems Engineering: Availability and Reliabilit
Adaptation of the Management Model of Internationalization Processes in the Development of Railway Transport Activities
No full textThe paper analyzes the importance of the system of management of internationalization processes in developing railway transport. The article also highlights the synergistic effect of a multilevel management model in internationalization processes. The main purpose of the paper was to establish a new model of management of internationalization processes in the frame of railway transport development, presenting a related management model. The article analyzes possibilities of integration of the national railway transport sector into global railway networks and provides a model for the management of internationalization processes in developing railway transport. The developed model was approved in an expert survey conducted in application of a questionnaire method. The goal of the expert evaluation was to ascertain the suitability of the theoretical management model of internationalization processes. Expert evaluation consisting of a questionnaire, the evaluation of concordance of expert opinions, and the results obtained were used in the analysis. The research led to the development of a new railway transport model using the “alliance + cluster” system, which is based on the management of internationalization processes. Many theoretical sources on internationalization processes were analyzed with the aim to adapt main advantages of the internationalization theory in the field of development of railway transport and its prospects for further researchThis article belongs to the Collection Sustainable Rail and Metro System
Factors Affecting Knowledge Sharing in Virtual Teams
No full textThe development and use of information and communications technology (ICT) are growing at a rapid speed across the world. ICT has been the cause for new types of work arrangements, such as virtual organizations, virtual teams, teleworking, etc. Virtual teams provide organizations with competitive advantage by enabling them to hire talented people across the world and eliminating the need for physical availability in the office. However, one major issue hindering the productivity of the virtual team is knowledge sharing. The lack of proper knowledge sharing between team members may cause organizations to fail with regards to the implementation of successful strategies. The research into understanding knowledge sharing in virtual teams (VT) in the Middle East is lacking. While such studies have been done in the United States and Europe, the Middle East has been overlooked. In this study, the authors assume that there are some specific behavioral aspects of VT in the Middle East that create the need for specific scientific solutions. Accordingly, this study was conducted in the Middle East in order to gain scientific knowledge on the region’s specificity. The objective of this article is to create a model for the evaluation of the effect on knowledge sharing in virtual teams in the Middle East. For analysis, the selection of companies includes United Arab Emirates (UAE)-based companies in the IT industry whose businesses engage in VT. The results show that the following factors have a direct effect on knowledge sharing in VT: Culture, motivation, conflict, ICT, trust, and leadership. Conversely, the results do not demonstrate that language has any impact on knowledge sharing. The methodology used is as follows: Literature review, survey methods, and structural equation modeling.This article belongs to the Special Issue Sustainable Virtual Organization: Management Challenges and Development Perspective
Bio-Based Polyurethane Composite Foams with Improved Mechanical, Thermal, and Antibacterial Properties
No full textAmong different organic fillers, the chemical composition of Syzygium aromaticum, commonly known as cloves, has great potential as a sustainable reinforcement for polymeric materials. In the study, grounded cloves were used as cellulosic filler for a novel polyurethane (PU) composite foams. Soybean oil-based PU composite foams were successfully reinforced with different concentrations (1, 2, and 5 wt%) of clove filler. PU foams were examined by rheological behavior, processing parameters, cellular structure (scanning electron microscopy analysis), mechanical properties (compression test, impact test, three-point bending test), thermal properties (thermogravimetric analysis), viscoelastic behavior (dynamic mechanical analysis) as well as selected application properties (apparent density, dimensional stability, surface hydrophobicity, water absorption, color characteristic). In order to undertake the disc diffusion method, all PU composites were tested against selected bacteria (Escherichia coli and Staphylococcus aureus). Based on the results, it can be concluded that the addition of 1 and 2 wt% of clove filler leads to PU composite foams with improved compression strength (improvement by ≈18% for sample PU-1), greater flexural strength (increase of ≈11%), and improved impact strength (increase of ≈8%). Moreover, it has been proved that clove filler may be used as a natural anti-aging compound for polymeric materials. Based on the antibacterial results, it has been shown that the addition of clove filler significantly improved the antibacterial properties of PU foams and is suitable for the manufacturing of antimicrobial PU composite foams. Due to these positive and beneficial effects, it can be stated that the use of cloves as a natural filler in PU composite foams can promote a new application path in converting agricultural waste into useful resources for creating a new class of green materials.This article belongs to the Special Issue Performance Research of Polyurethane Foams and Composite
Multi-Criteria Decision-Making (MCDM) for the Assessment of Renewable Energy Technologies in a Household: A Review
No full textDifferent power generation technologies have different advantages and disadvantages. However, if compared to traditional energy sources, renewable energy sources provide a possibility to solve the climate change and economic decarbonization issues that are so relevant today. Therefore, the analysis and evaluation of renewable energy technologies has been receiving increasing attention in the politics of different countries and the scientific literature. The household sector consumes almost one third of all energy produced, thus studies on the evaluation of renewable energy production technologies in households are very important. This article reviews the scientific literature that have used multiple-criteria decision-making (MCDM) methods as a key tool to evaluate renewable energy technologies in households. The findings of the conducted research are categorized according to the objectives pursued and the criteria on which the evaluation was based are discussed. The article also provides an overview and in-depth analysis of MCDM methods and distinguishes the main advantages and disadvantages of using them to evaluate technologies in households.This article belongs to the Special Issue Sustainable Energy ReviewsThis project has received funding from the European Social Fund (project No 09.3.3-LMT-K-712-02-0015)
under a grant agreement with the Research Council of Lithuania (LMTLT)
Evolution of Microbial Composition and Enzymatic Activities during the Composting of Textile Waste
Get PDFThe production of stable and mature compost often depends on the performance of microbes and their enzymatic activity. Environmental and nutritional conditions influence the characteristics of microbial communities and, therefore, the dynamics of major metabolic activities. Using three waste mixtures (textile waste mixed with either green, paper, or cardboard waste), the maturity of the compost produced was assessed by following the physico-chemical parameters and enzymatic activities provided by the microorganisms that were identified using next-generation sequencing (NGS). Among the three mixtures used, it was found that the two best mixtures showed C/N ratios of 16.30 and 16.96, total nitrogen of 1.37 and 1.39%, cellulase activities of 50.62 and 52.67 Ug−1, acid phosphatase activities of 38.81 and 68.77 Ug−1, and alkaline phosphatase activities of 51.12 and 56.86 Ug−1. In addition, several lignocellulosic species, together with those that are able to solubilize phosphate, were identified. Among those known for cellulase and acid/alkaline phosphatase activities, bacteria belonging to the Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes phyla were shown. The presence of species belonging to the Ascomycota and Basidiomycota phyla of Fungi, which are known for their ability to produce cellulase and acid/alkaline phosphatases, was demonstrated. These findings provide a basis for the production of stable and mature compost based on textile waste.This article belongs to the Special Issue Production and Application of Microbial Lignocellulose—Degrading Enzymes)This research was supported by the National Center for Scientific Research in Rabat (CNRST)
and Research Council of Lithuania (LMT) grant S-MIP-19-61 to J.U. The visit of S.B. to Vilnius Gediminas
Technical University was supported by an Erasmus + program. The APC was funded by Vilnius Gediminas
Technical University