VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Multi-stakeholder optimal energy supply for multi-family houses under 2021 German market conditions
No full textEspecially in the energy supply of multi-family houses, a wide variety of stakeholders are involved, from owners, to users, to energy service providers and society. They usually have different requirements and understandings of optimality, but ultimately have to make joint decisions and thus sensible compromises. In Germany in particular, there are a large number of multi-family houses and, at the same time, many government restrictions and subsidies in terms of energy supply. This makes it difficult to make clear recommendations for the choice of an energy supply concept that takes all stakeholder interests into account. We first identify the relevant stakeholders and define their objectives. In order to relate these with one another, we present a methodology based on energy system simulation and TOPSIS to make energy concepts objectively evaluable. A generic multi-family house with 40 residential units is examined, combining different energy technologies and insulation standards. There is no energy concept that satisfies all stakeholders equally and it is difficult to build coalitions between them. The best results are achieved by air-source heat pumps in combination with photovoltaic
Analytical discussion on applicability of frequency domain decomposition method to systems excited by an impulse force
No full textThis paper focuses on the use of vibration measurements for the purpose of cost-effective performance evaluation for the safety management and maintenance of Japan’s social infrastructure like bridges. Since modal properties are often used to diagnose damage of structures by analysing their changes, various modal identification methods have been developed in the past few decades. Among these, the FDD method has still attractive attention because of its simplicity and practicality. It is also highly applicable to simultaneous observation at multiple points and even complex modes can be identified instantly. On the other hand, the applicability of this method to impact tests applied to evaluate the condition of structures has not been sufficiently discussed to date. In this study, we will clarify the applicability to impact tests by reconstructing the theoretical background of the FDD method. Furthermore, we will show from theory that when there is a correlation between inputs, higher-order singular values, which should be noted when applied to impact tests, will be affected. The conclusions obtained from the reconstruction of the theoretical background will be verified based on numerical experiments and actual observation records
Performance-based design of strip foundation considering the full effect of ground improvement
No full textGround improvement is an effective way to improve the bearing capacity of a shallow foundation. However, the benefit of reducing uncertainties in soil parameters for shallow foundation design is rarely recognized. This study investigated the full effect of rapid impact compaction (RIC) on a strip foundation design. The finite difference method coupled Monte Carlo simulation were used to calculate the failure probability and the required width of the strip foundation, where the friction angle of soil was treated as a random variable. The results show that the foundation width reduces by 48.5% when considering the full effect of RIC, and a significant part of the reduction came from the decrease in the uncertainty of friction angle. Although the adopted relationship between the friction angle and tip resistance of cone penetration test affects the designed width of the foundation, the full effect of ground improvement contributed by the uncertainty reduction of soil parameters is still significant. The implication of the present study provides a basis for the performance-based bearing capacity design of shallow foundations
Evaluation of water permeability in compacted sand-bentonite liners from landfill using planning and factorial analysis
No full textCompacted Clay Liners (CCL) are designed to prevent environmental contamination in landfills. These layers are designed with low permeability soils, which are difficult to obtain. To this end, bentonite can be added. The objective of this work is to evaluate the reliability of factor analysis on the hydraulic performance of sand-bentonite mixtures. Two types of designs were used, with the variables controlled: compaction energy (CE), water content (U) and percentage of bentonite (B). Experimental layers were made to obtain water permeability (kw). The results showed that CE and B are, respectively, the factors that most influence permeability. The application of adequate energy promotes better accommodation of bentonite soil particles in the voids in the sand, which, when moistened, undergo an expansion process, reducing the voids in the layer. All of these parameters can be optimized by using a curvature design to obtain kW. Therefore, knowledge of CCL kw is essential to ensure the safety of the local environmental environment
Evaluation of noise exposure levels of pedestrians in suburban Chennai, India
No full textThe study assessed traffic noise exposure levels of citizens walking on the sidewalks at important road crossings in commercial land zone regions of Chennai’s suburbs. The noise data from signalized and unsignalized intersections are collected with a class I sound level meter for peak and non-peak hours from 6 AM to 10 PM. Different noise indices like A-weighted equivalent continuous noise level (Leq), Traffic Noise Index (TNI), Noise Pollution Level (Lnp) and Noise Climate (NC) are calculated and compared with Central Pollution Control Board (CPCB, 2017) and WHO standards. The inhabitants’ noise exposure levels are at an average value of 80–107.1 dB(A) which is alarmingly higher than the threshold levels of 70 dB(A) by WHO. A Risk Exposure Assessment (REA) questionnaire survey conducted on the area revealed that unsafe health situations persist for the public in the study regions
Development of cost functions for wastewater treatment by sequential batch reactor
No full textSequential batch reactor is widely used for industrial wastewater treatment. To consider sequential batch reactor for biological treatment of wastewater at a specific site, it is essential to ensure economy and sustainability. An approach for scrutiny of economic aspects may be based upon use of cost functions to compare sequential batch reactor and other technologies. Such approach will enable to conduct prudent analysis and select the most economic treatment scheme for a particular project. In most of published studies, the cost functions for conventional wastewater treatment systems are described with historic or some other data available to the investigators. No detailed engineering exercise related to cost functions for sequential batch reactor is cited in earlier research studies. In this document the novel and appropriate methodology has been presented to develop cost functions based on engineering, estimation and statistical approach to forecast cost for sequential batch reactor based wastewater treatment system
Soil physical quality indices of mining-induced disturbances in soil within the Loess region of western China
No full textSoil sampling and in situ measurements were conducted at 24 locations at three time points from May 2015 to April 2016. The statistical analysis showed that the variabilities of soil water content and soil penetration were moderate, while particle size and soil saturated hydraulic conductivity varied considerably. Rainfall before measurements contributed positively to the mean soil water content and negatively to particle size. This was mainly due to the soil aggregates and large soil particles being broken into smaller particles from rain splash. The detached small-sized soil particles could coalesce into larger-sized ones and even soil aggregates. Stressors in zones differ, resulting in variations between soil physical quality indices. The point-to-point comparisons indicated that the mean measured soil water content and soil saturated hydraulic conductivity were similar, if the measurements for these two indices were conducted under similar weather conditions during the same period between years. The investigation on the relationships among soil physical quality indices showed a negative relationship between the measured soil water content and soil saturated hydraulic conductivity. A positive correlation was also found between soil particle size and soil saturated hydraulic conductivity. Lower soil strength resulted in higher soil saturated hydraulic conductivity
Rail freight accessibility of the Visegrád Group countries and Baltic States in the context of Eurasian rail transport system
No full textThis study aimed to determine the level of infrastructure-based rail freight accessibility and rail freight performance of several Central and Eastern European (CEE) countries in the context of their presence in the Eurasian rail freight transport system. The study′s object was 7 CEE countries: Estonia, Lithuania, Latvia, Poland, Czechia, Slovakia and Hungary. The research methodology was based on the TOPSIS method supplemented with literature and statistical analyses. Several selected numerical indicators were considered to create 2 rankings that displayed the results achieved by countries in terms of accessibility and performance. Results showed that Czechia is the leader in infrastructure-based accessibility, with Latvia closing the ranking, and Lithuania is the leader in rail freight performance, with Hungary closing the ranking. Even though the study did not allow to confirm that a country′s rail freight accessibility affects its rail freight performance and vice versa, it can be assumed that both parameters are crucial in the context of the incoming modal shift to rail freight in Eurasia; therefore, they constitute a valuable research endeavour
The impact of ESG strategies on growth in the logistics industry
No full textThe aim of the article is to analyse the relationship between company growth, measured as an increase in Earnings Per Share (EPS) in 3- and 5-year periods, and companies’ financial condition, measured using the Altman z-Score (AS) model. The study was carried out on the example of companies included in the WIG Index and Warsaw Stock Exchange Index (in Polish: Warszawski Indeks Giełdowy – WIG) Environmental, Social, and Governance (ESG) between 2013 and 2020. Furthermore, among the companies included in the WIG index, companies belonging to the logistics industry were distinguished. An analysis of linear and panel relationships was used to verify the nature of the relationships between the variables taken into account. The z-Altman index was found to have a positive effect on company growth in a 3-year period for companies from the transport and logistics industry and all companies included in the WIG ESG index. Regarding company growth over the longer 5-year period, the influence of the z-Altman index on growth was not observed. Therefore, the results for companies in the WIG index show that for company growth in both the 3- and 5-year periods, the financial and economic condition of a company, measured by the z-Altman index, has no impact on the size of this growth, which was also confirmed by panel models
Risk analysis of road traffic accidents in Ukraine
No full textThis article presents a comprehensive investigation into the causes of road transport accidents in Ukraine, focusing on the application of risk analysis to minimize economic and human losses. The study begins with a detailed examination of the current road safety scenario in Ukraine, highlighting the alarming statistics of road accidents and their consequences. The central aim is to develop effective strategies for controlling and managing the causes of road accidents. The research identifies the primary factors contributing to road accidents, such as exceeding safe speed limits, driving under the influence of alcohol, etc. A risk management system is proposed, encompassing the creation of a structured risk management framework, development of methodologies, and implementation of information and analytical systems. The article emphasizes the importance of continuous risk monitoring and assessment, including risk identification, analysis, and management. Statistical observations and analysis play a crucial role in diagnosing risks, which are then used to devise risk minimization measures and improve road safety. The study concludes with recommendations for risk-based decision-making and the implementation of targeted interventions to reduce road accidents and associated risks in Ukraine.
First published online 11 February 202