Vilnius Gediminas Technical University
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4122 research outputs found
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Concepts and Capabilities of In-House Built Nanosecond Pulsed Electric Field (nsPEF) Generators for Electroporation: State of Art
No full textElectroporation is a pulsed electric field triggered phenomenon of cell permeabilization, which is extensively used in biomedical and biotechnological context. There is a growing scientific demand for high-voltage and/or high-frequency pulse generators for electropermeabilization of cells (electroporators). In the scope of this article we have reviewed the basic topologies of nanosecond pulsed electric field (nsPEF) generators for electroporation and the parametric capabilities of various in-house built devices, which were introduced in the last two decades. Classification of more than 60 various nsPEF generators was performed and pulse forming characteristics (pulse shape, voltage, duration and repetition frequency) were listed and compared. Lastly, the trends in the development of the electroporation technology were discussed.This article belongs to the Special Issue Electroporation Systems and Application
The Causal Connection of Natural Resources and Globalization with Energy Consumption in Top Asian Countries: Evidence from a Nonparametric Causality-in-Quantile Approach
No full textGiven the significance of energy conservation as a prime objective of environmental sustainability, countries all around the world are keen to identify significant factors that lead to the augmentation of energy utilization. Considering the rising emphasis of economies in utilizing natural resources to attain higher levels of globalization, the current research was aimed at investigating how the returns of natural resources and globalization affect energy consumption in top Asian economies. In doing so, the study emphasized the nonlinear relationship among the variables and applied the novel nonparametric method of causality in quantile to identify the quantile-based causal connection of natural resources and globalization on the returns and volatility of energy utilization in selected Asian countries. Moreover, the presence of nonlinearity in the variables was tested by the Brock- Dechert-Scheinkman test (BDS test), which confirmed that all variables showed nonlinear behavior. Furthermore, the findings of quantile cointegration confirmed a nonlinear long-run relationship of natural resources and globalization with energy utilization. The prime findings of causality in quantile revealed that the returns of natural resources and globalization had a significant causal effect on the returns of energy consumption in all countries. On the other hand, the volatility in energy consumption concluded no causal association with the returns of natural resources and globalization in any of the studied Asian countries. The findings are beneficial for the policymakers to formulate policies that will help to reduce the level of energy consumption.This article belongs to the Special Issue Innovation in Energy Security and Long-Term Energy Efficiency
A Novel Integrated Approach to Solve Industrial Ground Floor Design Problems
No full textThe ground floors of buildings usually have high loads from racks and other storage equipment in industrial buildings and logistics centers. Such types of buildings commonly require lift trucks. Therefore, there are special requirements for flatness tolerance across and along the driving track of truck lifts. Structural design solutions must be optimized and sustainable. The article reviews the behavior of soils and the importance of the actual behavior assessment of soils during the design of the ground floor on the elastic subgrade. The behavior of the ground floor’s areas above pile foundations that support the building’s columns is essential. Calculation results show the impact of subgrade stiffness on the behavior of reinforced concrete (RC) floor slab, especially in areas above pile foundations, where the stiffness of subgrade is much higher. The research provides a solution to achieve the required level of settlement dissimilarity in areas where there are piles underneath a building slab under the columns. The paper proposes a new integrated method for the evaluation of the subgrade reaction coefficient above the pile cap. The proposed method optimizes design time and eliminates the need for specialized geotechnical software. Obtained results confirmed the efficiency of the proposed design method.This article belongs to the Section Sustainable Engineering and Scienc
Electrochemotherapy Using Doxorubicin and Nanosecond Electric Field Pulses: A Pilot in Vivo Study
No full textPulsed electric field (PEF) is frequently used for intertumoral drug delivery resulting in a well-known anticancer treatment—electrochemotherapy. However, electrochemotherapy is associated with microsecond range of electrical pulses, while nanosecond range electrochemotherapy is almost non-existent. In this work, we analyzed the feasibility of nanosecond range pulse bursts for successful doxorubicin-based electrochemotherapy in vivo. The conventional microsecond (1.4 kV/cm × 100 µs × 8) procedure was compared to the nanosecond (3.5 kV/cm × 800 ns × 250) non-thermal PEF-based treatment. As a model, Sp2/0 tumors were developed. Additionally, basic current and voltage measurements were performed to detect the characteristic conductivity-dependent patterns and to serve as an indicator of successful tumor permeabilization both in the nano and microsecond pulse range. It was shown that nano-electrochemotherapy can be the logical evolution of the currently established European Standard Operating Procedures for Electrochemotherapy (ESOPE) protocols, offering better energy control and equivalent treatment efficacy.This article belongs to the Special Issue Novel Physical and Chemical Methods for Facilitated Drug DeliveryThis research was funded Research Council of Lithuania, grant number S-MIP-19-2
Evaluation of Elite Athletes Training Management Efficiency Based on Multiple Criteria Measure of Conditioning Using Fewer Data
Full text linkInnovative solutions and techniques in the sports industry are commonly used and tested in real conditions. Elite athletes have to achieve their peak performance before the main competition of the year, which is the World Championship, and every fourth year before the Olympic Games, when the main competition of athletes takes place. The present study aims to analyze and evaluate the ability of elite kayakers to achieve the best form at the right times, with the Olympic Games taking the greatest importance. Target values for multiple measures of conditioning are compared to target values set by experts. A weighted least squares metric with weights varied by time period is developed as a measure of fulfillment of the athletes’ conditioning plans. The novelty of the paper is the idea of using linear combination of polynomials and trigonometric functions for approximating the target functions and application of the proposed methodology for the optimization and evaluation of athletic training.This article belongs to the Special Issue Mathematical Methods in Applied Science
Fire Suppression and Thermal Behavior of Biobased Rigid Polyurethane Foam Filled with Biomass Incineration Waste Ash
No full textCurrently, there is great demand to implement circular economy principles and motivate producers of building materials to integrate into a closed loop supply chain system and improve sustainability of their end-product. Therefore, it is of great interest to replace conventional raw materials with inorganic or organic waste-based and filler-type additives to promote sustainability and the close loop chain. This article investigates the possibility of bottom waste incineration ash (WA) particles to be used as a flame retardant replacement to increase fire safety and thermal stability under higher temperatures. From 10 wt.% to 50 wt.% WA particles do not significantly deteriorate performance characteristics, such as compressive strength, thermal conductivity, and water absorption after 28 days of immersion, and at 32 °C WA particles improve the thermal stability of resultant PU foams. Furthermore, 50 wt.% WA particles reduce average heat release by 69% and CO2 and CO yields during fire by 76% and 77%, respectively. Unfortunately, WA particles do not act as a smoke suppressant and do not reduce smoke release rate.This article belongs to the Special Issue New Trends in Polymer Science: Health of the Planet, Health of the Peopl
Assessing the Sustainability of Alternative Structural Solutions of a Building: A Case Study
No full textThe implementation of sustainable solutions in the design of buildings is one of the main elements in achieving the transition to sustainability. The variety of structural elements and availability of sustainable materials, and the different preferences of clients, architects, and structural designers make the decision-making process difficult. This research aims to develop a decision model for applying to the early design stage. This work evaluates the sustainability of the load-bearing structures of a commercial building. Three types of load-bearing structures have been selected and compared concerning different physical parameters, cost of construction, cost of materials, technological dimensions (duration expressed in person-hours and machine-hours), and environmental impact. The methodology combines the building information modeling, sustainability criteria, and multi-criteria decision-aiding methods. The presented case study illustrates the proposed approach. The study revealed that multi-criteria decision aiding methods give the possibility to improve the selection process and to assess the sustainability of alternative structural solutions at an early stage of building design. The proposed decision model is versatile and therefore can be applied for different cases.This article belongs to the Special Issue Sustainable Development of Buildings: Design, Construction, Quality Inspection, Operation Managemen
Seasonal Variation of Indoor Radon Concentration Levels in Different Premises of a University Building
No full textIn the present study, we aimed to determine the changes of indoor radon concentrations depending on various environmental parameters, such as the outdoor temperature, relative humidity, and air pressure, in university building premises of different applications and heights. The environmental parameters and indoor radon concentrations in four different premises were measured each working day over an eight-month period. The results showed that the indoor radon levels strongly depended on the outside temperature and outside relative humidity, whereas the weakest correlations were found between the indoor radon levels and indoor and outdoor air pressures. The obtained indoor radon concentration and environmental condition correlations were different for the different premises of the building. That is, in two premises where the ventilation effect through unintentional air leakage points prevailed in winter, positive correlations between the radon concentration and outside temperature were obtained, reaching the values of 0.94 and 0.92, respectively. In premises with better airtightness, negative correlations (R = −0.96 and R = −0.62) between the radon concentrations and outside temperature were obtained. The results revealed that high quality air isolation in premises could be an important factor for higher indoor radon levels during summer compared to winter.This article belongs to the Special Issue Advances in Indoor Environmental Quality, Healthiness, and Sustainability of Educational Building
The diagnostics of bankruptcy threat to enterprises
No full textDisertacijoje nagrinėjama įmonių bankroto problematika: bankroto diagnostika, jo prognozavimo metodai ir prevencijos priemonės. Pagrindinis disertacijos tikslas – parengti kryptingą įmonių bankroto grėsmės diagnostikos sistemą, adaptuojamą greitai kintančioms verslo sąlygoms, sudarančią galimybę iš esmės padidinti bankroto numatymo patikimumą.
Disertaciją sudaro įvadas, keturi skyriai ir mokslinį darbą apibendrinančios išvados, taip pat literatūros šaltinių sąrašas, autorės publikacijų disertacijos tema sąrašas ir priedai (pateikti elektroninėje laikmenoje).
Įvade aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas ir uždaviniai, aprašoma tyrimų metodika, ginamieji teiginiai, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė. Įvado pabaigoje pateikiama disertacijos struktūra.
Pirmajame skyriuje analizuojama įmonių bankroto statistika, bankroto veiksniai ir prieţastys, įmonių krizės stadijos ir įmonių bankroto prevencija, kurios kertinė dalis yra bankroto diagnostika.
Antrajame skyriuje atliekama kritinė mokslinės literatūros, skirtos finansinės analizės, įmonių bankroto diagnostikos, prevencijos ir jų metodų bei priemonių problematikai, analizė. Nustatoma esamo įmonių bankroto diagnostikos (tame tarpe bankroto prognozavimo modelių) metodinio potencialo atitiktis praktikos poreikiams.
Trečiajame skyriuje aprašomi empiriniai tyrimai, atlikti siekiant patikrinti populiariausių įmonių bankroto prognozavimo modelių patikimumą ir tinkamumą. Tyrimo rezultatais grindžiami reikalavimai baziniam įmonių bankroto grėsmės diagnostikos sistemos komponentui – integruoto vertinimo modeliui. Pateiktas tokio modelio prototipas ir jo adaptavimo specifinėms taikymo sąlygoms algoritmas.
Ketvirtajame skyriuje išdėstoma parengta kompleksinė, kryptinga, naujais principais grindžiama įmonių bankroto grėsmės diagnostikos sistema, susidedanti iš trijų susietų skirtingo turinio analizės komponentų. Taikant šią sistemą įmonių bankroto grėsmės diagnostika atliekama pagal principą: nuo bendriausio (integruoto įverčio) iki konkretaus (probleminių sričių įverčių ir diagnozuotą būklę lėmusių prieţasčių) vertinimo. Nustatytos diagnostikos etapų tarpusavio sąsajos ir jų turinys.
Disertacijos tema yra išspausdinta 15 mokslinių publikacijų: šeši straipsniai
– EBSCO Business Source Complete duomenų bazėje referuojamuose žurnaluose, du straipsniai – recenzuojamuose mokslo žurnaluose ir septyni – konferencijų, kuriose padaryti pranešimai, straipsnių rinkiniuose.Daktaro disertacij
137Cs IR 90Sr pernašos iš dirvožemio į spygliuočius medžius tyrimas ir įvertinimas
No full textSummary of doctoral dissertationSummary of doctoral dissertatio