Vilnius Gediminas Technical University
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Mechanical Performance of Biodegradable Thermoplastic Polymer-Based Biocomposite Boards from Hemp Shivs and Corn Starch for the Building Industry
No full textBio-sourced materials combined with a polymer matrix offer an interesting alternative to traditional building materials. To contribute to their wider acceptance and application, an investigation into the use of wood-polymer composite boards is presented. In this study, biocomposite boards (BcB) for the building industry are reported. BcB are fabricated using a dry incorporation method of corn starch (CS) and hemp shiv (HS) treatment with water at 100 °C. The amount of CS and the size of the HS fraction are evaluated by means of compressive bending and tensile strength, as well as microstructure. The results show that the rational amount of CS independently of HS fraction is 10 wt.%. The obtained BcB have compressive stress at 10% of deformation in the range of 2.4–3.0 MPa, bending of 4.4–6.3 MPa, and tensile strength of 0.23–0.45 MPa. Additionally, the microstructural analysis shows that 10 wt.% of CS forms a sufficient amount of contact zones that strengthen the final product.This article belongs to the Section Biomaterial
Scientific Decision Framework for Evaluation of Renewable Energy Sources under Q-Rung Orthopair Fuzzy Set with Partially Known Weight Information
No full textAs an attractive generalization of the intuitionistic fuzzy set (IFS), q-rung orthopair fuzzy set (q-ROFS) provides the decision makers (DMs) with a wide window for preference elicitation. Previous studies on q-ROFS indicate that there is an urge for a decision framework which can make use of the available information in a proper manner for making rational decisions. Motivated by the superiority of q-ROFS, in this paper, a new decision framework is proposed, which provides scientific methods for multi-attribute group decision-making (MAGDM). Initially, a programming model is developed for calculating weights of attributes with the help of partially known information. Later, another programming model is developed for determining the weights of DMs with the help of partially known information. Preferences from different DMs are aggregated rationally by using the weights of DMs and extending generalized Maclaurin symmetric mean (GMSM) operator to q-ROFS, which can properly capture the interrelationship among attributes. Further, complex proportional assessment (COPRAS) method is extended to q-ROFS for prioritization of objects by using attributes’ weight vector and aggregated preference matrix. The applicability of the proposed framework is demonstrated by using a renewable energy source prioritization problem from an Indian perspective. Finally, the superiorities and weaknesses of the framework are discussed in comparison with state-of-the-art methods.This article belongs to the Special Issue Sustainable Energy Economics and PolicyThe research was funded by University Grants Commission (UGC), India and Department of Science &
Technology (DST), India under the grant nos. F./2015-17/RGNF-2015-17-TAM-83 and SR/FST/ETI-349/2013
The Place and Face of the Stranger in Levinas
No full textThis essay addresses the topic of place, more specifically it raises the question how and why place is essential for defining the strangeness of the other person. In Levinas’ philosophy the Other as stranger is the one whom I welcome to my home and country, i.e., to my place. This essay takes up three interrelated topics: (1) the general notion of place; (2) the ethical notion of place in Levinas’ philosophy, contrasted with an ontological notion of place. The deepest significance and virtue of place appears not in my dwelling or my compatibility with being but at the site from which the I is able to welcome the Other. Furthermore, the “ownness” of my place is always contested by the stranger as I have no necessity, no ultimate right to be; (3) the strangeness of the Other in Levinas’ philosophy defined not by topology but by vulnerability. To welcome the stranger and give up my place comes from my infinite responsibility for the Other. On the ethical level, the vulnerable face of the Other cannot be objectified and classified.This article belongs to the Special Issue Levinas and the Politica
Achievements of the European Union Countries in Seeking a Sustainable Electricity Sector
No full textThe electricity production sector has a significant share of final energy consumption and has a huge potential to use more renewable energy sources. Over the last two decades, the European Union (EU) reform of electricity markets has had positive results, and market liberalization acts as a stimulus for energy efficiency, lower prices, and technological progress. Today’s EU policy for the development of electricity and the entire energy sector seeks to provide system modernization, stability, reinforcement of the single market, and implementation of climate change policy with an emphasis on the decarbonization of energy sources and the increase of energy efficiency. After all of the EU efforts to form an electricity sector in member states, it is necessary to assess the efficiency of the policy implemented and to identify the results achieved in shaping a sustainable electricity sector. The purpose of this article is to carry out a sustainability assessment of the electricity sector in the EU countries. A set of eight indicators designed to assess the sustainability of the electricity sector of different EU countries in 2017 has been drawn up. The assessment is made using the multi-criteria decision-making method (MCDM) Technique for Order Preference (TOPSIS). The assessment shows that the electricity market of Slovenia is the most sustainable, with Luxembourg in the second position in the EU.This article belongs to the Special Issue Development and Implementation of Models of Electricity Market 2019This project has received funding from European Social Fund (project No 09.3.3-LMT-K-712-02-0015) under grant agreement with the Research Council of Lithuania (LMTLT)
Hierarchical Decision-making using a New Mathematical Model based on the Best-worst Method
No full textDecision-making processes in different organizations often have a hierarchical and multilevel structure with various criteria and sub-criteria. The application of hierarchical decision-making has been increased in recent years in many different areas. Researchers have used different hierarchical decision-making methods through mathematical modeling. The best-worst method (BWM) is a multi-criteria evaluation methodology based on pairwise comparisons. In this paper, we introduce a new hierarchical BWM (HBWM) which consists of seven steps. In this new approach, the weights of the criteria and sub-criteria are obtained by using a novel integrated mathematical model. To analyze the proposed model, two numerical examples are provided. To show the performance of the introduced approach, a comparison is also made between the results of the HBWM and BWM methodologies. The analysis demonstrates that HBWM can effectively determine the weights of criteria and sub-criteria through an integrated model
FEM-Based Compression Fracture Risk Assessment in Osteoporotic Lumbar Vertebra L1
No full textThis paper presents a finite element method (FEM)-based fracture risk assessment in patient-specific osteoporotic lumbar vertebra L1. The influence of osteoporosis is defined by variation of parameters such as thickness of the cortical shell, the bone volume–total volume ratio (BV/TV), and the trabecular bone score (TBS). The mechanical behaviour of bone is defined using the Ramberg–Osgood material model. This study involves the static and nonlinear dynamic calculations of von Mises stresses and follows statistical processing of the obtained results in order to develop the patient-specific vertebra reliability. In addition, different scenarios of parameters show that the reliability of the proposed model of human vertebra highly decreases with low levels of BV/TV and is critical due to the thinner cortical bone, suggesting high trauma risk by reason of osteoporosis.This article belongs to the Special Issue Biomaterials for Bone Tissue Engineerin
Sustainable Reuse of Groundwater Treatment Iron Sludge for Organic Matter Removal from River Neris Water
Get PDFThe most important advances in sustainability in the water industry are focused on the reuse of water treatment sludge. The Antaviliai Water Supply Plant, which is located in Lithuania, treats groundwater by removing iron and manganese from it. This technology does not produce water waste, as the iron sludge is used for recycling. In this study, iron sludge received from groundwater treatment is used to remove natural organic matter from river Neris water, which can be used as drinking water. Twelve doses (from 1 to 6 g/L and from 0.1 g/L to 0.9 g/L) of iron sludge powder, with acid and without it, were used. The most effective removal of organic compounds (55.51%) and reduction in water colour (53.12%) were observed when 0.3 g of iron sludge powder and 8 ml of 0.95% H2SO4 solution were added to the tested water. It was found that the use of a conventional coagulant (Al2(SO4)3*17H2O), with and without iron sludge powder, decreased the concentration of organic compounds and water colour from 2.8 to 28.2% compared with the use of a pure coagulant (Al2(SO4)3*17H2O) alone.This article belongs to the Special Issue Water-Energy Sustainable Urban Developmen
An Evidential Model for Environmental Risk Assessment in Projects Using Dempster–Shafer Theory of Evidence
No full textOne of the goals of sustainable development is to achieve economic and social growth according to environmental criteria. Nowadays, impact assessment is an efficient decision making method in planning and management with environmental perspectives. Environmental risk assessment is a tool to reduce the impacts and consequences of various activities on the environment in order to achieve sustainable development. One of the commonly used environmental risk assessment methods is the probability–impact matrix method, which is known as a quantitative method for risk assessment of projects. In this method, numerical estimates of probability and impact of risk occurrence are very difficult, and these factors are associated with uncertainty. When uncertainty exists, data integration is of great importance, for which the fuzzy inference system and evidence theory are known as effective methods. Unavailability of experts’ opinion and the exponential growth of the number of required fuzzy rules associated with the risk factors are two drawbacks of fuzzy inference. Dempster–Shafer’s theory of evidence is one of the popular theories used in intelligent systems for modeling and reasoning under uncertainty and inaccuracy. In this paper, an evidential model for project environmental risk assessment is proposed based on the Dempster–Shafer theory, which is capable of taking into account the uncertainties. The proposed model is used to assess the environmental risks of Maroon oil pipelines in Isfahan. In addition, the proposed model is used in the case of tunneling risk assessment taken from the subject literature. To evaluate the validity of the proposed evidential model, the results are compared in two case studies, with the results of the conventional risk assessment method and the fuzzy inference system method. The comparative results show that the proposed model has a high potential for project risk assessment under an uncertain environment.This article belongs to the Special Issue Sustainability and Risks in Construction Managemen
Fatigue Behavior of Concrete Beams Prestressed with Partially Bonded CFRP Bars Subjected to Cyclic Loads
No full textThe lack of ductility is the greatest concern in the applications of carbon fiber reinforced polymer (CFRP) materials, when used as pre-stressing reinforcements. To improve the ductility, a partially bonded FRP system which is intentionally unbonded in the middle part of the beam and bonded in both end parts of the beam has been developed and applied to prestressed concrete beams. While, many researchers investigated the instantaneous performance of partially bonded CFRP prestressed concrete beams, this study intended to evaluate the fatigue performance, the static load-carrying capacity after fatigue loading and ductility. Based on the fatigue loading tests followed by static loading tests, over-reinforced and web-confined partially bonded CFRP prestressed concrete beams exhibited satisfactory fatigue performance without cracks and stiffness degradation during fatigue loading. In addition, no degradation of load-carrying capacity was observed in static loading tests after the fatigue tests. The ductility index of concrete beams, prestressed with partially bonded CFRP bars, is combined with over-reinforcements and web-confinements, similar to that of beams prestressed with steel bars.This article belongs to the Section Construction and Building MaterialsThis research was funded by the Ministry of Education Grant No. NRF-2018R1D1A1B07049074 and by Ministry of Education Grant No. NRF- 2016R1D1A1B03931172
Study on the Effect of Graphene Oxide with Low Oxygen Content on Portland Cement Based Composites
No full textThe current study presents research into the effect of graphene oxide (GO) with a carbon to oxygen ratio of 4:1 on the fluidity, hydration, microstructure, mechanical and physical properties of Portland cement pastes and mortars. The amounts of GO investigated were 0.02%, 0.04%, and 0.06% by weight of cement, while for mortars, an extra composition with 0.1% was also prepared. According to the results, the fluidity of cement paste and mortar increased and the hydration process was slightly retarded with the addition of GO. Despite this, improvements in compressive and flexural strength were established in the mortars containing GO. The maximum effects (~22% and ~6%, respectively) were obtained with the addition of 0.06% GO. The calculation of estimated strength proportional to samples of equal density showed that for mortars cured for 7 days the gain in strength was directly related to the gain in density. For mortar samples cured for 28 days, the estimated strength was found to be significantly higher than that of the reference sample, indicating that besides density there are other factors determining the improvement in strength of mortars modified with GO. The possible structure strengthening mechanisms are discussedThis article belongs to the Section Construction and Building Material