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Performance analysis of different gun silencers
No full textWith the rapid development of the military industry and the increasing focus on the safety of those in these fields, there is an increasing search for solutions to existing and emerging weapons for the user and the environment. In this case, components for firearm suppression are used to reduce the effects of noxious impulse sound, to minimize the severity of the weapon’s recoil to the user’s body, and maintain important accuracy, maneuverability and other parameters. The analysis and investigation of silencer designs can provide essential values for acoustic characteristics that reduce risk in real situations. The gun silencer analysis was performed in two steps. The modeling processes of the silencer configuration were performed to choose the optimal construction, and the main parameters were selected, including different angles and forms of the tilt. The angle of inclination of the partitions was changed to 60° and 135°. Due to the reduced results observed in the last zones with closed cavities and created additional configurations, the number of partitions was shortened by three partitions and the angle of inclination was adjusted to 60°; the simulation of the initial variant was also supplemented with 135° partitions. The second step was an experimental validation of the optimal tilt angle and form according to the modeling data. The silencer was found to achieve a sound pressure damping value and the sound pressure level during the shot was reduced to below a dangerous level. The search to find the optimal configurations will lead to the parameters of production and efficiency.iss. 7vol. 1
The bus constructions safety and reliability of Small serial buses of production manufactured in Lithuania
No full textBaigiamajame magistro darbe išanalizuoti originalaus ir žemagrindžio autobusų porėmiai, įvertinti porėmių įtempiai ir deformacijos, apskaičiuotas žemagrindžio autobuso porėmio patikimumas. Naudojantis moksline literatūra, apžvelgti porėmių projektavimo, modeliavimo ir optimizavimo principai bei metodai. Analizei buvo pasirinktas „Mercedes-Benz Sprinter“ autobuso originalus porėmis ir „Mercedes-Benz Sprinter Altas“ žemagrindžio autobuso porėmis. Išanalizuotos ir apskaičiuotos porėmius veikiančios skersinės jėgos, lenkimo momentai ir įlinkiai. Visi atsparumo skaičiavimai atlikti „Static Beam“ kompiuterine programa. Naudojantis programiniu paketu „SolidWorks 2014“ sukurti porėmių erdviniai modeliai. Atliktas porėmių modeliavimas veikiant išilginėms ir skersinėms apkrovoms. Nustatyti ir palyginti pavojingi įtempiai, deformacijos ir įlinkiai. Nustačius silpniausią žemagrindžio porėmio konstrukcijos vietą, atliktas konstrukcijos pakeitimas ir įvertinti gauti nauji duomenys (nustatyta, kaip pasikeitė didžiausi įtempiai pasikeitus konstrukcijai). Naudojantis programiniu paketu „Ansys 14,5“ atliktas porėmių modeliavimas, veikiant dinaminei apkrovai. Nustatyta, kaip deformuojasi porėmiai, kada porėmius veikia kintanti apkrova (imituojamas automobilio atsitrenkimas į kliūtį). Taip pat naudojantis patikimumo skaičiavimo teorija, išanalizuotas ir įvertintas konstrukcijos patikimumas eksploatacijos metu. Darbo apimtis – 70 psl. teksto be priedų, 47 iliustracijos, 7 lentelių, 39 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai.Original and low-floor buses frames, the stresses and strains and low-floor bus frame reliability have been analysed in final Master degree thesis. Using science literature there were reviewed design, modeling and optimization principles of frames. For research there were chosen “Mercedes – Benz Sprinter” bus original frame and “Mercedes – Benz Sprinter Altas” low-floor bus frame. In thesis have been analyzed and calculated cross forces, bending moments and deflections. All calculations of strength were performed “Static Beam” software. By using program “SolidWorks 2014” there were made CAD models. Also there was made simulation of frames when the external loads act. There was identified and compared the stress, strain and deflection. Identified the weakest low-floor bus frame place, there was made simulation of changed form frame to ensure that stress in dangerous points decreased because of shape change in part. By using program “Ansys 14,5” there was made simulation of frames when the dynamic loads act (simulated vehicle collision with the obstacle). Furthermore, using the theory of reliability, analyzed and assessed reliability of the construction, during operation. Thesis consists of 70 p. of text without appendixes, 47 pictures, 7 tables, 29 bibliographical entries. Appendixes included
Research of technological process of manufacturing optical elements
No full textBaigiamajame magistro darbe nagrinėjama poliravimo greičio (įrankio sukimosi dažnio), prispaudimo jėgos bei proceso trukmės įtakapaviršiausformos nuokrypiamsirpaviršiųšiurkštumui,apdirbant„Suprasil“medžiagą.Aprašytadarboatlikimometodika, įrankiai, įranga bei medžiagos. Atlikta analogiškų ir panašių tyrimų apžvalga. Atlikti eksperimentiniai tyrimai, išmatuoti dominantys formosnuokrypiųbeipaviršiųšiurkštumoparametrai,gautirezultataiapdorotitaikant statistikosįvertinimoprograminęįrangą, pateiktosišvados.Ištirta,jogkiekvienoparametropakeitimaituriįtakosbendramruošiniokokybiniamrezultatui. Baigiamąjį darbą sudaro 56 psl. be priedų, 3 lentelės, 56 pav., 12 bibliografinių šaltinių, 3 psl. priedų.The final master thesis examines the influence of polishing speed(tool speed),compression force,and process duration on surface shape deviations and surface roughness when processing “Suprasil” material. Methods of work performance, tools, equipment and materials are described. An overview of analogous and similar studies has been performed. Experimental studies were performed,parameters of the shape deviations and surface roughness were measured,the obtained results were processed using statistical evaluation software and conclusions were given. It has been investigated that changes to each parameter affect the overall qualitative result of the workpiece. The final work consists of 56 pages without appendixes, 3 tables, 56 pictures,12 bibliographical entries, 3 p.annexes
Comparison of mathematical models of torque transmitted by multi-disc wet clutch with experimental results
No full textIn the paper results of experimental tests on a multi-disc wet clutch are presented. Typical, single-sided multi-disc wet clutch was analysed. Experimentally obtained data present torque capacity of the clutch with varying number of friction surfaces. The results are also compared to characteristics obtained based on several known mathematical models. It was found that differences between most of known models describing torque transmitted by clutches and experimental results are considerable. The best correspondence between model and experiment was reached for Bąk’s model. Nevertheless, differences between the model and data gained via experiment might differ substantially i.e., characteristic of proposed model are mostly shifted upwards in relation to experimental characteristics. The paper also includes a brief description of a test stand and its scheme. The article presents also a figure which contains diagrams presenting all characteristics as functions of average contact pressure on friction surfaces
Identifying how increased economic growth may be attributed to sustainable development
No full textThe United Nations has issued an urgent call to action to promote collaboration with programs that support sustainable development. This is one of the methods to drive economic growth, and the United Nations’ call to action supports such cooperation. However, no established method exists for measuring individual sustainable initiatives’ impact on the overall economic growth rate. This study aims to evaluate and investigate sustainable decisions’ impact on the company’s economic performance in General. In the context of this research, the phrase “sustainable decisions” refers to any choices made by Entrepreneurs that contribute to the overall development of an organisation on several fronts, including the social, environmental, and economic fronts. The results of this study can be exploited as a method for capturing society’s attention to raise social awareness of the need to invest in sustainable options. Furthermore, they will assist in the design and execution of future research efforts and the development of environmentally friendly technologies with regard to economic development.Taip / Yes
The effect of of metakaolin used as cement replacement on the properties of hardened cement paste /
No full textThe article analyses the effect of expanded glass production by-product rich in metakaolin on the properties of hardened cement paste. Portland cement CEM II/A-LL 42.5 N with the average particle size of 14.21 μm and metakaolin with the average particle size of 22.34 μm were used for the tests. Six cement paste compositions were formulated by replacing 0 %, 2 %, 4 %, 6 %, 8 %, 10 % of cement with metakaolin. Ultrasonic pulse velocity, compressive strength, flexural strength, water absorption and porosity of hardened cement paste specimens were measured at 28 days. The analysis of hardened cement paste microstructure (SEM) and physical and mechanical properties leads to the conclusion that the replacement of 8% of cement in the mix with metakaolin creates the densest microstructure that produces the highest values of compressive and flexural strengths and ultrasonic pulse velocity and the lowest values of closed porosity and water absorption rate. It was found that 8 % was the optimal ratio of cement replacement with metakaolin. Metakaolin can be added at 8 % by weight of cement in the production of modified high-performance concrete.vol. 1
Eco-innovation performance of Lithuania in the context of European environmental policy: Eco-innovation indicators and efficiency
No full textThe European Union (EU) has made eco-innovation and green technology a priority as they are essential to the continent’s long-term prosperity. To move towards sustainable economic growth, eco-innovation takes a significant role in the transition process. The aim of the article is to use the eco-innovation indicators as an instrument to measure the eco-innovation performance of Lithuania in the context of the EU Green Deal in order to analyze and assess the components and indicators of the eco-innovation index for Lithuania. Following the aim of the article, a set of re-search hypotheses will be formulated. The evaluation of eco-innovation indicators in Lithuania relative to EU countries using Eco-IS indicators, determination of eco-innovation efficiency using the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method, and identification of necessary eco-innovation policies for sustainable growth are the objectives of this paper. The re-search results present the positive impact of eco-innovation activities in the EU on Lithuania, and vice versa. Lithuania was affected positively by eco-innovation activities of other EU nations. The outcome of the study indicates its relevance by highlighting Lithuania’s position among the lowest countries in terms of eco-innovation adoption, hence new research pathways for the creation and implementation of policies to solve the current situation are provided.iss. 4vol. 1
Shrinking Cities: case study of compact city centre development in Panevėžys
No full textBaigiamajame magistro darbe nagrinėjama besitraukiančių miestų problema, gilinamasi į šios problemos priežastis ir šiuolaikinius sprendimo būdus, pasitelkiant užsienio šalių patirtį. Pritaikoma pagrindinė tokio pobūdžio miestų plėtros strategija – kompaktiško miesto vystymas, koncentruotas į centrinę miesto dalį. Pasitelkiant kompaktiško miesto vystymo principus ir atsižvelgiant į išanalizuotus Panevėžio centro struktūrinius ir vizualinius aspektus, atskeidžiančius šio miesto centro identitetą, formuojama Panevėžio centrinės dalies vystymo koncepcija. Vienas iš pagrindinių šios koncepcijos elementų yra architektūrinių kompleksų plėtra Nevėžio pietinėje pakrantėje, baigiamajame darbe įvardintoje ,, kultūriniu šlaitu“, kuris apsijungęs su vienu iš pagrindinių kompaktiško miesto plėtros principų – būsto pasiūlos skatinimu mišriose centro teritorijose pasitelkiant transektą, suformuoja naują darnios plėtros strategiją. Visa tai atsispindi ir detalizuojamame koncepcijos fragmente. Siūloma plėtros strategija potencialiai turėtų sumažinti miesto traukimasi ir skatinti gyventojų skaičiaus augimą bei regeneruojant centrinę dalį išryškinti jos svarbą viso miesto kontekste, kuri šiuo metu yra ženkliai sumažėjusi.This Master thesis is focused on the main reasons and solutions of shrinking cities phenomenon. The main strategy of these cities development which was adapted in other European countries as the most modern and effective way is a compact planning canalized on central part of the city structure. By using main compact development principles and analysis of Panevezys city centre urban scheme, historical layers, system of spaces and visual aspects there has been revealed the identity of centre and formed a concept of city centre development. One of the most important elements of the concept is the spread of urban complexes at Nevezis river valley during various historical times, especially at soviet era, which has formed the appearance of ,cultural valley“. Two major directions – compact development and spread of cultural valley is based on residential houses variety supply and mixed land use by applying transect model and forming sustainable structural development in lost spaces of this area. All these features have been reflected on detalization part of the concept. Suggested development strategy potentially could be the solution of shrinking and population growth by regenerating central part and bringing out the importance of the city in the context of all area of Paneveys, which nowadays is widely decreased
The Industrial Robot UR5 Control Research
No full textŠiame magistro baigiamajame darbe tiriama pramoninio roboto UR5 valdymo galimybė, panaudojant CAD/CAM technologiją. Literatūros apžvalgoje išnagrinėti pramoninių robotų tematikos moksliniai leidiniai ir \"Universal Robots\" žinynai. Teorinėje dalyje apžvelgti pramoniniai robotai, jų parametrai ir charakteristikos. Išnagrinėti UR5 roboto valdymo būdai, CAD/CAM technologija ir jos programinė įranga. Tiriamojoje dalyje išnagrinėti nauji UR5 roboto valdymo būdai ir URScript programavimo kalbos universalumas. Išanalizuotos CAD/CAM programos, jų lankstumas, paredaguoti valdymo programos generavimo algoritmai. Išbandytos sugeneruotos roboto valdymo programos ir eksperimentiškai nustatyti optimalūs roboto judesio parametrai. Atlikus sistemos tyrimą, pateiktos baigiamojo darbo išvados ir pasiūlymai. Darbą sudaro 5 dalys: įvadas, literatūros apžvalga, teorinė ir tiriamoji dalys, išvados ir pasiūlymai, literatūros sąrašas. Darbo apimti - 68 p. teksto be priedų, 27 pav., 9 lent., 36 bibliografiniai šaltiniai. Atskirai pridedami 4 darbo priedai.The Master thesis is a research of the industrial roboto UR5 control, using CAD/CAM technology. Review of literature contains study of scientific publications of industrial robots and \"Universal Robots\" manuals. Theoretical part is an overview of industrial robots, their properties and characteristics. There are analysis of UR5 control methods, CAD/CAM technology and their software. The research part contains of analysis of new UR5 robot control methods and flexibility of URScript programing language. Properties of the CAD/CAM software are tested to change post-processor. Experimantal system sudy is performed to test generated programs for UR5 robot control also finding optimal move parameters. The conclusions and recommendations are given at the end of this work. Structure: introducion, review of literature, theoretical and practical parts, conclusions and suggestions, references. The thesis consists of 68 p. text without appendixes, 27 pictures, 9 tables, 36 bibliographical entries. 4 appendixes included
Railway infrastructure of Ukraine as a factor of soil chemical hazard (analytical overview)
No full textTo reach the aim in solving these tasks, the following theoretical methods of research were used, mainly
analysis, experimental data, complex assessment of hazardous influence of railway infrastructure on the environment, mainly soil chemical pollution, which are an essential part of railway infrastructure. Considering the comparative characteristics, we can make a prognosis on any heavy metal impact with excessive content of acid and alkaline properties of polluted soils. A result of scientific research an analytical review of the issue of railway infrastructure in Ukraine as a factor of soil chemical hazard and determination of the main sources of pollution among the enterprises of rail transport.Taip / Ye