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Comparison of same aftermarket monotube shock absorbers manufactured by different brands
No full textSuspension keeps the wheels of the vehicle in contact with the road surface, dampens various vibrations that arise due to road surface irregularities and ensures adequate control of the vehicle. The performance of the suspension is directly related to shock absorbers, which are an integral part of the suspension. As there are many options of various aftermarket shock absorbers, quality and price are the main factors that define the driver’s choice. However, the main question is how different can the same aftermarket monotube shock absorbers be, which were designed for a specific vehicle, but were manufactured by different brands? To answer this question, further described research presents the experimental analysis and comparison of damping characteristics of the same aftermarket monotube shock absorbers, which were manufactured by different brands. During the analysis, in total, 8 completely new shock absorbers manufactured by 4 different brands were compared, and the effects of the initial shock absorber temperature were also taken into account
Improving the energy efficiency of a vehicle by implementing an integrated system for utilizing the thermal energy of the exhaust gases of an internal combustion engine
No full textThe rapid increase in the number of fossil fuel vehicles in recent decades has led to stricter standards for their environmental safety, carbon dioxide emissions and fuel efficiency. Advances in the production technologies of the internal combustion engine (ICE) and systems that ensure its operation have led to a significant reduction in emissions of harmful substances with exhaust gases. Meanwhile, increasing the thermal efficiency of the internal combustion engine without significantly increasing production and operating costs is an urgent task and one of the priority areas of scientific research in this field. The article considers the most rational schemes for the recovery of thermal energy of exhaust gases, which ensure the minimization of operating costs of the vehicle. The implementation of the proposed system of complex energy-efficient disposal is evaluated taking into account the expectations of compliance with the requirements for emissions of harmful substances with exhaust gases during the operation of the vehicle
Pacientų, hospitalizuotų dėl COVID-19 ligos, mirties ligoninėje tikimybės vertinimas taikant statistinius ir mašininio mokymosi metodus
No full textKoronaviruso SARS-CoV-2 sukelta liga COVID-19 paveikė daugumą pasaulio šalių. Pandemijos metu ypač padidėjo apkrova sveikatos priežiūros sistemoms. Siekiant suvaldyti didelius besikreipiančių į ligoninių priėmimus ir hospitalizuojamų pacientų srautus, buvo ieškoma priemonių kuo tiksliau įvertinti pacientų būklę. Tam pasitelkiamos įvairios klinikinio vertinimo skalės, tokios kaip NEWS [1], COVID-GRAM [2], laboratorinių tyrimų indeksai ir kt. Vis dėlto skirtingų šalių patirtys vertinant šių rodiklių sąsajas su gydymo ligoninėje baigtimis skiriasi [3]. Naudodami nuasmenintus 2020 - 2022 metais dėl COVID-19 Vilniaus universiteto ligoninėje Santaros klinikose hospitalizuotų pacientų duomenis, išbandėme įvairius statistinius ir mašininio mokymosi metodus mirties ligoninėje tikimybei įvertinti, įtraukiant apskaičiuotą NEWS rodiklį, laboratorinių tyrimų rezultatus, informaciją apie gretutines pacientų ligas, pacientų lytį ir amžių. Pranešime bus pristatyti atlikto tyrimo rezultatai
Optimization of damping in a semi-active car suspension system with various locations of masses
No full textThe key request for a vehicle suspension system is vibration control and decreasing the actual inertia forces. This ensures ride comfort for the crew and influences the fatigue level of the driver and overall driving safety. Implementing semi-active damping control in the vehicle suspension allows for adjusting the damping process in the vehicle for minimum acceleration applied to the seats, driver, and passengers. In order to implement theoretical analysis, we used a mathematical full-car model in Simulink/MATLAB. As the load, we added simulations of various artificially generated road profiles. The damping coefficient of the semi-active suspension system was optimized for maximum comfort level for a driver only. Results from the full-car simulation process deliver a graph of the output accelerations showing kinematic excitation from road deformities under various locations of vehicle load positions.iss. 9vol. 1
Optimization of sound-absorbing and insulating structures with 3D printed recycled plastic and tyre rubber using the TOPSIS approach
No full textStudies on recycled materials emerged during recent years. This paper investigates the properties of sound absorption and transmission loss of the structures of the perforated plastic panel (PPP) backed with the rubber granule panel (RGP). Under production conditions, such a structure could be produced using only waste. The normal incidence sound absorption and transmission loss of the structure was measured using ISO 10534-2 and ASTM E2611-17 standard methods, respectively. In this study, the plastic panel perforation holes were tilted in steps of 15°–45° compared to the vertical axis of the sample. Different thickness rubber panels were used as backing (12 mm, 22 mm and 27 mm). The results showed that the sound absorption and transmission loss increased with the angle of the perforation pore. To compare the different structures, the multi-criteria analysis using the technique for order of preference by similarity to ideal solution (TOPSIS) approach was done. The RGP thickness, sound absorption coefficient (SAC) and sound transmission loss (STL) were weighted as a criterion. The results of the multi-criteria analysis showed that the optimal structure for a possible application is PPP45°+ RGP 22 mm, which was ranked highest of all alternatives. The first peak of SAC reached 0.97 at 1000 Hz. In the frequency range of 250–1000 Hz, STL values reached up to 10.4 dB and in the frequency range of 1–4 kHz – 20.1 dB. The results obtained using RGP and PPP show promising development potential for sound absorption and insulation applications.iss. 00vol. 0
Automatic generation of 3D scenes and animations using XML format
No full textMagistro darbo metu yra analizuojami automatinio 3D scenos ir animacijos generavimo metodai, problemos ir jų sprendimo būdai bei atliekamas jau egzistuojančių sistemų ir metodų įvertinimas. Pagal literatūros analizę iš apžvelgtų algoritmų ir metodų išrinkti geriausi ir suprojektuotas naujas XML struktūra paremtas 3D scenų ir animacijų generavimo metodas. Suprojektuotas metodas naudoja klasifikatorių, kuris analizuoja naudotojo įvestą tekstą, apdoroja ir struktūrizuoja gautus duomenis su būsimos 3D scenos aprašymu į XML formato struktūrą. Remiantis pasiūlytu metodu įgyvendintas sistemos prototipas. Remiantis išanalizuotais darbo rezultatais, pateikiami pasiūlymai dėl tolesnės automatinio 3D scenų generavimo ir animacijos temos plėtros. Darbą sudaro: įvadas, literatūros analizė, automatinio 3D scenos generavimo metodų apžvalga, projektavimas, įgyvendinimas, testavimas, išvados, literatūros sąrašas. Darbo apimtis 79 p. teksto be priedų, 31 paveikslai, 9 lent. ir 50 literatūros šaltiniai.The Master's thesis analyses methods, problems and solutions for automatic 3D scene and animation generation and evaluates existing systems and methods. Based on the literature analysis, the best algorithms and methods are selected from the reviewed ones and a new XML structure based method for 3D scene and animation generation is designed. The designed method uses a classifier that analyses the text entered by the user, processes and structures the resulting data with a description of the future 3D scene into an XML format structure. Based on the proposed method, a prototype system has been implemented. Based on the analysed results of the work, suggestions for further development of the topic of automatic 3D scene generation and animation are presented. The thesis consists of: introduction, literature analysis, review of methods for automatic 3D scene generation, design, implementation, testing, conclusions, reference list. The thesis consists of 79 pages of text without appendices, 31 figures, 9 tables and 50 references
Crosstalk reduction in high-density radio frequency printed circuit boards: Leveraging FR4 coating layers
No full textThe escalating component density in radio frequency (RF) systems presents a growing challenge related to the coupling of adjacent microstrip lines in high-density printed circuit boards (PCBs). As a result, to tackle this prominent issue, there is a continuous pursuit of innovative techniques to effectively minimize the coupling effects among closely spaced microstrip lines. This paper proposes a reduction in the coupling of adjacent lines by utilizing a coating (stiffener) layer, which is commonly used in rigid-flex PCB fabrication. For this purpose, a reference 50 Ohm coupled line performance was compared to three coupled lines with track widths of 1.39 mm, 1.30 mm, and 1.25 mm, respectively, all at a fixed distance between the tracks. These decreasing widths were used to achieve the same 50 Ohm impedance for the coupled lines when covered with different coating layers. Each of these three coupled lines was covered with different coating (stiffener) layers, measuring 0.1 mm, 0.3 mm, and 0.5 mm in thickness, respectively. The manufactured device under test (DUT) structures underwent time-domain reflectometry (TDR) and S-parameter measurements. The TDR measurements of the DUT structures with coating layers demonstrated excellent conformity to the 50 Ohm reference coupled line. Meanwhile, the S21 measurements indicated a significant decrease in the crosstalk. For example, for a coating layer thickness of 0.3 mm, the crosstalk decreased by approximately 5–6 dB within the frequency range up to 5 GHz. When the coating layer thickness was 0.5 mm, the crosstalk decreased by approximately 10 dB or more.iss. 10vol. 1
Addiction Prevention Center in Vilnius, Kirtimai
No full textBaigiamajame magistro studijų darbe nagrinėjama narkomanijos problema Vilniaus mieste, jos paplitimas bei įtaka visuomenei. Analizuojama bei lyginama užsienio šalių ir esama Lietuvos priklausomybių prevencijos praktika. Darbo tikslas – parengti idėjinį priklausomybių prevencijos centro projektą, kuris spręstų narkomanijos problemą, kontroliuotų plitimą bei mažintų jos sukeliamą žalą. Analitinėje dalyje pateikiama užsienio šalių praktikos analizė. Išskiriamos priklausomybių prevencijos centrams būdingos charakteristikos. Išanalizuojamas problemos mastas Vilniaus mieste. Identifikuojamos probleminės miesto zonos. Pateikiamas esamų priklausomybių prevencijos priemonių vertinimas, išskiriami jų trūkumai bei galimybės. Projektinėje dalyje pateikiami konceptualūs priklausomybių prevencijos centro probleminėje miesto zonoje, Kirtimuose šalia romų taboro, pasiūlymai. Aprašomos siūlomo objekto charakteristikos. Praktiniu požiūriu šis darbas gali būti naudingas kaip analizės objektas vystant priklausomybių prevenciją Lietuvoje. Darbo tekstinę dalį sudaro: įvadas, tiriamoji dalis, projektinė dalis, išvados ir apibendrinimai, informacijos šaltinių sąrašas. Prie darbo atskirai pridedami priedai, 10 planšetų ir 2 maketai.The final master thesis examines drug addiction problems in Vilnius, it’s spread and impact on society. Drug abuse prevention in foreign countries is compared with Lithuanian practice. The aim is to prepare conceptual addiction prevention center project, which would solve drug abuse problems, control it’ s spread, and reduce it’ s harmful consequences. The analytical part presents analysis of foreign addiction prevention practices, examines main characteristics of addiction prevention centers. Vilnius town analysis shows scale of addiction phenomenon, reveals problematic spaces. Analytical part evaluates existing addiction prevention practices, shows it’s lacks and possibilities. The design part includes conceptual proposal for addiction prevention center in problematic place of Vilnius. In practical terms, this work can be useful as an object of analysis for developing further addiction prevention in Lithuania. The written part of the work consists of introduction, analytical part, project part, conclusions and suggestions, references. Appendixes: 10 tablets and 2 models are added separately
Visibility of Lithuania universities in the public space and motives for students choice
No full textLietuvoje kasmet sudaromi aukštųjų mokyklų reitingai, viešojoje erdvėje analizuojami universitetų studijų programų privalumai ir trūkumai. O universitetai konkuruoja dėl būsimų studentų, kurių skaičius lemia ir valstybės , ir privačias dotacijas. Norėdami sudominti ir pritraukti tikslinę auditoriją – būsimus studentus, universitetai kuria savo įvaizdį: viešojoje erdvėje akcentuoja geriausias savo savybes, tikslus, uždavinius, naudodamiesi viešosios komunikacijos kanalais. Universitetai investuoja daug išteklių į viešąją savo įvaizdžio komunikaciją, tačiau Lietuvoje nėra tyrimų apie Lietuvos universitetų viešosios komunikacijos rezultatus, grįžtamąjį ryšį, kokie universiteto įvaizdžio aspektai yra svarbiausi būsimiems studentams. O kitose Europos valstybėse tyrimai, vertinantys universitetų viešąją komunikaciją ir būsimų studentų poreikį tokiai komunikacijai daromi jau ne vienerius metus. Tai padeda universitetams ne tik stiprinti, bet ir keisti savo įvaizdį atsižvelgiant į būsimų studentų poreikius. Todėl darbe kaip pagrindas tyrimui apžvelgta užsienio universitetų viešosios įvaizdžio komunikacijos elementai ir atlikta Lietuvos universitetų, esančių reitingų viršūnėse, viešosios įvaizdžio komunikacijos analizė.Higher education institutions in Lithuania are ranked annually and the advantages and disadvantages of university study programs are analyzed in the public sphere. Meanwhile, universities are competing for prospective students, whose numbers determine both public and private grants. In order to attract the target audience - prospective students - universities create their image in a sense: they emphasize their best qualities, goals and objectives in the public sphere by using public communication channels. Universities invest a lot of resources in the public communication of their image, but in Lithuania there is no research on the results of public communication of Lithuanian universities, feedback on what aspects of the university image are most important for future students. In other European countries, meanwhile, studies assessing university public communication and the need of future students for such communication have been ongoing for years. This helps universities not only to strengthen but also to change their image according to the needs of future students. Therefore, as the basis for the research, the public image communication elements of foreign universities were reviewed and public image communication analysis of Lithuanian universities at the top of the rankings was performed.
Reconceptualizing film policy and its model in the Baltic film industries: from political economy towards mission economy
No full textIn the recent years financial support for national film production in Lithuania, Latvia and Estonia has risen up to a level that was not possible when the film policy was still in the development stage. Consequently, the stability of financial support growth for national film production allows to question the current film policy model in the Baltic film industries in regard to mission economy approach where goal orientation, market shaping and co-creating, finance and long-term orientation towards dynamic institutions, sustainability, value and the collective process involving business, government and public participation. The development of film policy model is also related with film distribution and exhibition processes since only when the Baltic States were celebrating their 100-year anniversary in 2018, first steps that were related with mission-oriented goals and policies were taken. Methodology is based on critical analysis of statistical data (quantitative descriptive statistics) and film policy and its regulation documents (qualitative content analysis). Accordingly, evaluation of analysis results and recommendations for improving film policy model is formulated.Taip / YesI