Vilnius Gediminas Technical University
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Filialų steigimo užsienyje modeliavimas plėtojant universiteto tarptautiškumą
Get PDFIt is argued in literature that the competitiveness of higher education institutions (HEIs) will increasingly depend on their ability to operate internationally in the near future (Delgado-Márquez et al., 2013; De Haan, 2014; De Wit, 2010; Graf, 2009). The emergence of entrepreneurial university phenomena as well as a shift in movement from students to the movement of programmes and universities lead to the emergence of one of the riskiest and unexplored entry modes to international markets in higher education – international branch campus (IBC). Risk reduction strategies of IBC establishment are analysed and suggested in this thesis.
The object of present study is international development of HEIs using a branch campus, thus addressing the problem of the lack of comprehensive theoretical and practical frameworks of transnational education activities. The aim of the thesis is to develop a decision support model for international branch campus establishment enhancing the university competitiveness in the foreign market.
The dissertation consists of the introduction, three chapters, general conclusions and 8 annexes. Chapter 1 reviews literature on the contemporary issues of internationalisation of higher education focusing on IBC management. Internationalisation theories and foreign market entry modes are analysed in business and higher education. The chapter is finalised with the formulation of the scientific problem of the dissertation.
Chapter 2 starts of by reviewing the research methodology for the development of the decision support model for IBC establishment enhancing the university competitiveness. Further, the empirical research for the development of the decision support model is presented. The following research methods have been used: analysis of statistical data, 4 expert surveys (3 on IBC development, 1 on networking), Delphi method, multicriteria decision support method (FARE), semi structured interviews, and computer assisted qualitative data analysis (CAQDAS) using Nvivo software.
Chapter 3 suggests and explains in detail the decision support model for the establishment of IBC. The model is based on the synergy of theoretical and empirical research results. During the theoretical analysis of the thesis, the theoretical basis of the model was formed, which was reasoned, elaborated and validated by the empirical research with the participation of four international expert groups. The model itself is presented in the third chapter, describing its empirical validation, as well as revealing the perspectives and limitations of its application. Also the model approbation is presented.
9 scientific articles focusing on the subject discussed in the dissertation have been issued (3 in international journals, 6 in international conference proceedings) and 1 chapter in a book published abroad.Doctoral dissertatio
Bioanglies iš sumedėjusios biomasės tyrimai bei technologijos kūrimas potencialiai toksiškų elementų adsorbcijai gerinti
Get PDFThe dissertation is focused on production and modification ligneous biochar for enhanced adsorption of potentially toxic elements (PTEs) from synthetic solutions and landfill leachate. The main object of the research is adsorption of Cr3+, Cd2+, Pb2+, Zn2+, Ni2+, Cu2+ by ligneous biochar. The goal is to assess adsorption of PTEs by biochar and develop technology for modification of ligneous biochar, possessing enhanced adsorption capacity for Cr3+, Cd2+, Pb2+, Zn2+, Ni2+, Cu2+. The thesis approaches several tasks. Task 1, 2, 3 are conducted by experimental studies of the key adsorption mechanisms, biochar characteristics, modification methods, biochar-hydrogel composite swelling and adsorption studies. Task 4 is conducted by theoretical research and numerical modeling studies of fitting to dynamic intraparticle model for adsorption of PTEs by ligneous biochar.
The dissertation consists of three parts including the introduction, 3 chapters, conclusions and references. The introduction discusses the research problem, the relevance of the thesis, describes the object of the research, formulates the aim and objectives of the thesis, describes the research methodology, scientific novelty of the thesis, the practical value of the research findings, defended statements. At the end of the introduction, the publications and reports published by the author on the topic of the dissertation and the structure of the dissertation are presented.
Production technologies of biochar from ligneous feedstock, biochar characteristics and modification techniques, as well as mechanisms of adsorption of potentially toxic elements on biochar, equilibrium isotherms and kinetic models of adsorption are presented in Chapter 1. Chapter 2 presents theoretical and experimental methods of selection of feedstock with variable intrinsic properties for biochar production, physical and chemical characteristics of biochar, equilibrium and kinetic modeling of adsorption, modification with H2O2, FeCl3, MgCl2 and preparation of biochar-hydrogel composite.
Chapter 3 investigates the effect of modification methods on the adsorption capacity for potentially toxic elements of ligneous biochar and identifies the key mechanisms of adsorption, evaluates the biochar-hydrogel composite potential for application in adsorption of potentially toxic elements from synthetic solutions and landfill leachate, develops the dynamic intraparticle model for adsorption of potentially toxic elements by biochar.
7 publications focusing on the subject of the discussed dissertation were published: 4 articles – in scientific journals included in the Clarivative Analytics Web of Science list (3 of them with citation index), and 3 – in conference proceedings. The 1 patent of the Republic of Lithuania was granted. 8 presentations on the subject have been presented in conferences at national and international level.Dissertatio
Analysis of deformation behaviour of reinforced concrete elements under pure tension
No full textDisertacijoje nagrinėjamas tempiamųjų armuoto betono elementų, veikiamų trumpalaike apkrova įtempių ir deformacijų būvis, atsižvelgiant į ilgalaikius procesus – traukumą bei valkšnumą, pasireiškusius betone iki mechaninės apkrovos. Nagrinėjamų deformacijų diapazonas nesiekia armatūros takumo ribos. Analizuojama nevienalytės betono struktūros įtaka tempiamųjų elementų deformacijoms ir pleišėjimui, atskleidžiant deterministinio požiūrio trūkumus. Apžvelgiami tempiamųjų elementų eksperimentinių tyrimų metodai, pabrėžiant jų ypatumus ir trūkumus. Aptariami armuoto betono deformacijų būvio modeliai, pagrindinį dėmesį skiriant šiuolaikiniams skaitinio modeliavimo metodams.
Disertacijos autoriaus ir kitų mokslininkų tyrimais įrodyta, kad tempiamojo sustandėjimo modelis yra svarbus veiksnys, užtikrinantis armuoto betono deformacijų bei pleišėjimo skaitinės analizės rezultatų adekvatumą. Didelė eksperimentinių rezultatų sklaida, dažniausiai siejama su stochastinio pobūdžio struktūriniais defektais bei ilgalaikiais procesais vykstančiais betone, komplikuoja modeliavimą. Dėl minėtų ilgalaikių procesų vykstančių betone, eksperimentiniai trumpalaikių bandymų rezultatai gali būti nepatikimi ir klaidinantys.
Pateikti skaitinio (baigtinių elementų metodo) modeliavimo rezultatai rodo, kad tempiamuosiuose elementuose deformacijos betone kinta ne tik išilgine elemento kryptimi, bet ir pačiame apsauginiame betono sluoksnyje. Rezultatai patvirtina, kad efektyviojo tempiamojo betono koncepcijos, taikomos projektavimo taisyklėse, adekvatumas nėra pakankamas ir priklauso nuo apkrovimo sąlygų, deformacijų būvio bei elemento geometrijos.
Darbe pasiūlytas stochastinio modeliavimo būdas, kuris galėtų būti taikomas tikimybiniame projektavime. Betono struktūros heterogeniškumas siejamas su tempiamojo sustandėjimo modeliu. Siūloma metodika paremta Monte Karlo stochastinio imitavimo samprata – struktūriniai atsakai generuojami vertinant a priori tempiamojo sustandėjimo tikimybinį pasiskirstymą. Prognozių (a posteriori) tikimybinis pasiskirstymas nustatomas pagal sugeneruotų rezultatų rinkinį. Stochastinių principų taikymas modeliuojant tempiamąjį sustandėjimą leidžia prognozuoti ne tik vidutines armuoto betono elemento deformacijas, bet ir vertinti šių prognozių pokyčius. Skirtingai nuo projektavimo ir mokslinių tyrimų praktikos, buvo atsižvelgta į betono traukumą esant trumpalaikiam apkrovimui.
Disertaciją sudaro įvadas, keturi skyriai, bendrosios išvados, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir penki priedai. Darbo tema paskelbti 9 straipsniai: 5 straipsniai žurnaluose, įtrauktuose į Mokslinės informacijos instituto (Clarivate Analytics) pagrindinį sąrašą, 2 – konferencijų straipsnių rinkiniuose, įrašytuose į Clarivate Analytics duomenų bazę, 2 – kitų konferencijų straipsnių rinkiniuose; skaityti 4 pranešimai Lietuvos ir kitų šalių konferencijose.Daktaro dsertacij
Challenges Caused by Increased Use of E-Powered Personal Mobility Vehicles in European Cities
No full textIncreased use of e-powered personal mobility vehicles is usually considered to be a positive change, while it is generally agreed that Personal Mobility Vehicles (PMVs) effectively and efficiently reduce the negative environmental impacts of transport and improve quality of life. There has been great technological progress made by all sectors in the field of personal mobility during the last decade. The use of PMVs for micro-mobility have been welcomed by the market, consumers, and governments and thus they are becoming increasingly popular in modern European society. New technology-driven PMVs provide opportunities to their users, but at the same time create problems with street space sharing, road safety, and traffic offenses. This study gives an overview of recent types of PMVs, offers some insights into upcoming changes and challenges, and raises a discussion on themes related to the increased use of e-powered personal transporters.This article belongs to the Special Issue Accessibility and Transportation Equit
Do Women Affect the Final Decision on the Housing Market? A Case Study
No full textThis article presents the results of research on the effect of the customer’s gender on the tenure choice (ownership or tenancy) on the housing market. In the study, an attempt has been made to investigate whether there is a significant role of women in making decisions in this market. The survey was conducted among residents of two cities—Olsztyn (Poland) and Vilnius (Lithuania). The obtained answers were subjected to a multi-dimensional categorical and quantitative analysis. The results showed, among others, that women generally have greater decision-making autonomy in residential issues than men, with Lithuanian women doing this much more often than Polish women. However, it should be noted that the dominant decision-making model in the housing market is the model of joint decisions taken by men and women. The results of the conducted analysis broaden the existing knowledge of the functioning of the housing market and may support the implementation of the pro-social and pro-sustainable spatial development policy of the given territorial unit. The results may also contribute to more sustainable development of enterprises in the housing construction sector. This is an important issue in a climate of intense competition between “providers” of flats and the gradual introduction of the idea of competition between them and the social environment.This article belongs to the Special Issue Sustainable Real Estate: Management, Assessment and InnovationsThis work was supported by the National Science Centre [grant number 2019/33/B/HS4/00072
Level of Pollution on Surrounding Environment from Landfill Aftercare
No full textThis work examines how the pollution from landfill aftercare effect the surrounding area and water basins. The subject of the study was a closed landfill where waste was disposed of without any accounting and operation of the landfill. During the study, soil, surface water, and sediment samples were taken over a two-year period. The data obtained compared with the maximum allowable concentrations established in the Northern part of Lithuania. The water sampling sites were selected taking into account the direction of the water flow, and the landfill was found to influence the water quality. Within 500 meters before the landfill, heavy metals and metalloid concentrations did not exceed the maximum allowable concentrations (Pb ≤ 20 µg/L; Ni ≤ 40 µg/L; Cr ≤ 100 µg/L; Cu ≤ 100 µg/L and As ≤ 20 µg/L). Soil and water sediment contamination factor and contamination level were determined for each metal and metalloid individually, which showed that as a single chemical element and its compounds none of them pose any danger to the environment. A different situation can be seen when calculating the total level of contamination, taking into account all pollutants classified as very hazardous, Zd > 10. The results showed that monitoring (of surface water, including soil) and investigations, helping to reduce negative environmental impact, should be continued in the closed landfill
Robust Multi-Objective Sustainable Reverse Supply Chain Planning: An Application in the Steel Industry
No full textIn the design of the supply chain, the use of the returned products and their recycling in the production and consumption network is called reverse logistics. The proposed model aims to optimize the flow of materials in the supply chain network (SCN), and determine the amount and location of facilities and the planning of transportation in conditions of demand uncertainty. Thus, maximizing the total profit of operation, minimizing adverse environmental effects, and maximizing customer and supplier service levels have been considered as the main objectives. Accordingly, finding symmetry (balance) among the profit of operation, the environmental effects and customer and supplier service levels is considered in this research. To deal with the uncertainty of the model, scenario-based robust planning is employed alongside a meta-heuristic algorithm (NSGA-II) to solve the model with actual data from a case study of the steel industry in Iran. The results obtained from the model, solving and validating, compared with actual data indicated that the model could optimize the objectives seamlessly and determine the amount and location of the necessary facilities for the steel industry more appropriately.This article belongs to the Special Issue Uncertain Multi-Criteria Optimization Problem
Towards Microorganism-Based Biofuel Cells: The Viability of Saccharomyces cerevisiae Modified by Multiwalled Carbon Nanotubes
No full textThis research aimed to evaluate the toxic effect of multi-walled carbon nanotubes (MW-CNTs) on yeast cells in order to apply MW-CNTs for possible improvement of the efficiency of microbial biofuel cells. The SEM and XRD analysis suggested that here used MW-CNTs are in the range of 10–25 nm in diameter and their structure was confirmed by Raman spectroscopy. In this study, we evaluated the viability of the yeast Saccharomyces cerevisiae cells, affected by MW-CNTs, by cell count, culture optical density and atomic force microscopy. The yeast cells were exposed towards MW-CNTs (of 2, 50, 100 μg/mL concentrations in water-based solution) for 24 h. A mathematical model was applied for the evaluation of relative growth and relative death rates of yeast cells. We calculated that both of the rates are two times higher in the case if yeasts were treated by 50, 100 μg/mL of MW-CNTs containing solution, comparing to that treated by 0 and 2 μg/mL c of MW-CNTs containing solution. It was determined that the MW-CNTs have some observable effect upon the incubation of the yeast cells. The viability of yeast has decreased together with MW-CNTs concentration only after 5 h of the treatment. Therefore, we predict that the MW-CNTs can be applied for the modification of yeast cells in order to improve electrical charge transfer through the yeast cell membrane and/or the cell wall.This article belongs to the Special Issue Carbon-Based Nanostructures and Nanocomposites for Health and Environmental ApplicationsThis project has received funding from the Research Council of Lithuania (LMTLT), agreement No [S-MIP-20-18]
Experimental Research on Quality Parameters of Recycled Concrete
No full textConcrete itself, and issues relating to the recycling and management of reinforced concrete waste, are highly relevant, especially when urban expansion is being achieved by increased building construction volumes. This research investigates concrete waste and its (re)usage possibilities and resolves several major issues related to the question of how natural materials can be replaced by compounds made from concrete waste, thereby saving natural resources. The experiment was carried out using concrete mixtures, which were combined with natural aggregates and crushed concrete waste (fraction 4/16). The resulting mix of concrete was achieved using natural aggregates, thus replacing natural aggregates with waste, which had partially and fully replaced bulky aggregates with crushed concrete waste. The main aim of the investigation was to investigate how aggregates made from crushed concrete waste impact the properties of concrete. The exothermic effect on the concrete mixture during the hardening process was investigated. Furthermore, a macrostructural analysis of hardened concrete was conducted using scanned sample images; the adhesion zone between newly formed concrete stone and aggregates derived from natural rock from crushed concrete waste was investigated. Using an electron microscope to observe aggregate from crushed concrete waste and the contact zone of hardened cement stone revealed that the aggregate from waste adheres poorly with hardened cement stone. Furthermore, both the mechanical properties of new, hardened concrete and determined resistance to frost indicators are weak. Concrete density and compression strength decreased (by up to 8% and up to 18%, respectively), and absorption increased almost twofold due to aggregates derived from crushed concrete waste, since their cleavage strength indicator was twice as high, while water absorption was four times higher than that of natural aggregate. The results indicate that recycled concrete obtained from demolished buildings is environmentally sustainable and can be recommended for lower quality concrete for use in related engineering projects.This article belongs to the Special Issue Research of Structure and Properties of Concretes Based on Non-conventional Aggregate
Gypsum, Geopolymers, and Starch—Alternative Binders for Bio-Based Building Materials: A Review and Life-Cycle Assessment
No full textTo decrease the environmental impact of the construction industry, energy-efficient insulation materials with low embodied production energy are needed. Lime-hemp concrete is traditionally recognized as such a material; however, the drawbacks of this type of material are associated with low strength gain, high initial moisture content, and limited application. Therefore, this review article discusses alternatives to lime-hemp concrete that would achieve similar thermal properties with an equivalent or lower environmental impact. Binders such as gypsum, geopolymers, and starch are proposed as alternatives, due to their performance and low environmental impact, and available research is summarized and discussed in this paper. The summarized results show that low-density thermal insulation bio-composites with a density of 200–400 kg/m3 and thermal conductivity (λ) of 0.06–0.09 W/(m × K) can be obtained with gypsum and geopolymer binders. However, by using a starch binder it is possible to produce ecological building materials with a density of approximately 100 kg/m3 and thermal conductivity (λ) as low as 0.04 W/(m × K). In addition, a preliminary life cycle assessment was carried out to evaluate the environmental impact of reviewed bio-composites. The results indicate that such bio-composites have a low environmental impact, similar to lime-hemp concrete.This article belongs to the Special Issue Advanced Construction and Architecture 2020Publication is created with support of European Regional Development Fund project “A new concept for low-energy eco-friendly house”, Grant Agreement No 1.1.1.1/19/A/017