Piston group of in-line three-cylinder diesel engine

Cílem této bakalářské práce je provést výpočet termodynamického cyklu daného motoru ze zadaných základních geometrických, termodynamických a provozních parametrů jeho pístnní skupiny. Dalším krokem je navrhnout rozměry válcové jednotky a pro vybrané provozní režimy provést pevnostní kontrolu pístu, pístního čepu a oka ojnice. V úvodu je uveden princip činnosti Dieselového motoru. Vlastní text práce se skládá z pěti částí a přílohy. V prvních dvou částech jsou postupně popsány základní parametry motoru a Sabatův termodynamixký cyklus. Dále je rozebráno silové zatížení pístu, pístního čepu a statické a dynamické napětí ojničního oka. Příloha se zabývá numerickým výpočtem tříválcového vznětového mototu Zetor 5202. V závěru je popsán postup, analýza a zhodnocení daného výpočtu. Nakonec je zde uvedeno porovnání teoretického pojetí problematiky s realitou v praxilThe aim of this thesis is to calculate a thermodynamic cycle of given engine with basic geometric, thermodynamic and operating parameters of is piston category. Then, a disign of cylindrical unit and strengrh check of piston, piston pin and conrod eye, follows. There is preliminary mentioned the principle of Diesel engine function. The body of the thesis is divided into five chapters and the attachment. At first two chapters, there are basic parameters of the engine and Sabat thermodynamic cycle described. Next chapters are focused on force load of piston, piston pin and static and dynamic stress of conrod eye. Numerical calculation of three-cylinder Diesel engine Zetor 5202 is given in the attachment. In conclusion, there is the procedure and the analysis of calculation described and zhe calculation is evaluated. Finally, a comparison of theoretical concept and real conditions is given.

Gear Timing Mechanism for Valvetrains

Cílem této bakalářské práce je získat všeobecný přehled o tomto způsobu pohonu ventilových rozvodů.Úvod se zabývá druhy ozubených kol a jejich použitím ve spalovacích motorech. Vlastní text práce se skládá ze tří částí. V první části je důkladně rozebrán pohon ventilového rozvodu ozubenými koly. V krátkosti jsou zde také popsány jednotlivé součásti ventilového rozvodu a jiné způsoby pohonu ventilových rozvodů. V rozboru pohonu ventilových rozvodů ozubeným soukolím je popsán princip záběru ozubených kol, přenos sil mezi ozubením, výhody použití čelních ozubených kol s šikmými zuby oproti přímým zubům, možné způsoby výroby ozubených kol, nejvhodnější materiály, tepelné zpracování ozubených kol a nejčastější poruchy ozubených kol. Druhá část práce se zabývá výhodami a nevýhodami použití ozubeného soukolí pro pohon ventilových rozvodů. Ve třetí časti jsou uvedeny příklady použití pohonu ventilových rozvodů ozubenými koly v praxi u traktorů, nákladních automobilů, lodí, lokomotiv, osobních automobilů a motocyklů. Závěr obsahuje přínos použití ozubeného soukolí u této problematiky a celkové zhodnocení práce.The objective of this thesis is to provide an overview of geared valvetrain. In introduction are described individual types of gears and their application in combustion engines. Then, the thesis is divided into three chapters. The first chapter provides a thorough analysis of geared valvetrain. Also, individual parts of valvetrain together with alternative methods of valve timing are briefly introduced. The chapter then follows to examine the working principle of gears, how forces and moments are transmitted, advantages of introducing helical gears instead of spur gears, different ways of gear manufacturing, gear material selection, heat treatment of gears and common gear failure mechanisms. The second chapter examines pros and cons of using geared valvetrains. The third chapter shows examples of how are geared valvetrains applied in tractors, trucks, ships, trains, cars and motorcycles. In the conclusion, the main advantages of using geared valvetrains are discussed and the whole thesis is summerized.

Frage. Perpetuo (The Humming Bird.) Two Pieces for Violin

n/

Souvenir

https://digitalcommons.library.umaine.edu/mmb-ps/1883/thumbnail.jp

Urban Renewal: Opportunity for Green Innovation in the Face of Climate Change, A Case Study of Toronto Community Housing

Cities around the world have established ambitious targets to reduce greenhouse gas emissions in order to limit the global average temperature increase to within 1.5°C of pre-industrial levels by 2050. The effects of climate change are felt globally but urban environments are enormous contributors to emissions. With the majority of the globe’s population residing in cities, they are the most vulnerable to the effects of climate change, which can be catastrophic. Urban renewal, the natural replacement and restoration of buildings, presents an opportunity to interject and guide development to a more sustainable trajectory, in a way that considers the benefits of ecological processes in cities. This major paper argues for the adoption of stronger green building standards in Toronto, beginning from the City’s own building stock of Toronto Community Housing (TCHC), in order to demonstrate leadership and protect the people who are most vulnerable to the negative effects of climate change. The paper does this by exploring the current green building best practices used in North America and how they demonstrate, or are limited in, supporting sustainable development. Consideration is given to whether building high-efficiency buildings is the best option for sustainable development by weighing different factors. Despite best practice weaknesses, ultimately, it is the benefits that are extracted from these practices that are important, rather than any form of certification. Green building development is explored by looking at a case study of TCHC, to understand how the City, as a public entity, can lead the way in green development. This research finds that TCHC is tenaciously using sustainability as a motivator for resident wellbeing, financial sustainability, and reduction in greenhouse gas emissions. However, the case study also reveals limitations to further development of TCHC’s green buildings and emission reductions. This paper identifies those limitations and formulates recommendations to facilitate further reducing emissions. The city’s overall greenhouse gas emission reductions have come to a halt, and this is a sign that additional measures need to be taken to continue to reduce emissions. Improving green building standards for renovations, investing in data collection, and addressing user behaviour through education are the recommendations given in this paper to take the next steps to further reducing building-related emissions. These recommendations will allow TCHC and its tenants to lead efforts to reduce the city’s greenhouse gas emissions. The recommendations focus on maximizing the benefits from green technologies. As a city, Toronto must consider the majority of the current building stock, which will continue to exist into 2050, as well as new buildings which will exist for much longer, in its efforts to further reduce greenhouse gas emissions

Serenade : Celebrated Kubelik Serenade

https://digitalcommons.library.umaine.edu/mmb-ps/1649/thumbnail.jp

Long-term potentiation at C-fibre synapses by low-level presynaptic activity in vivo

Inflammation, trauma or nerve injury trigger low-level activity in C-fibres and may cause long-lasting hyperalgesia. Long-term potentiation (LTP) at synapses of primary afferent C-fibres is considered to underlie some forms of hyperalgesia. In previous studies, high- but not low-frequency conditioning stimulation of C-fibres has, however, been used to induce LTP in pain pathways. Recently we could show that also conditioning low-frequency stimulation (LFS) at C-fibre intensity induces LTP in vitro as well as in the intact animal, i.e. with tonic descending inhibition fully active. In the slice preparation, this form of LTP requires a rise in postsynaptic Ca2+-concentration and activation of Ca2+-dependent signalling pathways. Here, we investigated the signalling mechanisms underlying this novel form of LTP in vivo. We found that the signal transduction pathways causing LFS-induced LTP in vivo include activation of neurokinin 1 and N-methyl-D-aspartate receptors, rise of [Ca2+]i from intracellular stores and via T-type voltage-dependent Ca2+ channels, activation of phospholipase C, protein kinase C and Ca2+-calmodulin dependent kinase II. These pathways match those leading to hyperalgesia in behaving animals and humans. We thus propose that LTP induced by low-level activity in C-fibres may underlie some forms of hyperalgesia

COMPANY TRAINING FROM THE EFFICIENCY AND EFFECTIVENESS POINT OF VIEW

The paper concentrates on the topic of efficiency and effectiveness of company training. This work has set research goals that were solved using the interrogation method, questionnaire technique and free interview. Goal No. 1 was to investigate the situation in the company training from the motivation aspect and stimulating education system requirements. Goal No. 2 was to determine the use of educational methods, forms of training from the point of view of their efficiency. Goal No. 3 was to investigate into the attitude toward company training evaluation and exploitation of the individual levels of educational process efficiency evaluation. As a resource for the training efficiency evaluation the authors used Kirkpatrick’s 4-level Learning Evaluation Model extended with the ROI method. The research group consisted of a) HR managers / managers from the SME sectors, b) participants of these companies’ training programmes. The most important requirements for an efficient stimulating educational system involve the conformity with the needs and goals of the company, linking with the performance system and accord with the needs of an individual. The research has shown that in certain educational methods and forms there occurs conformity between the frequency of their usage in practice and apprehension of their efficiency, e.g. the controlled discussion method and the direct group education form. In others, such as the practical example method and individual consultation form, their usage in practice is minimal, but there is a high apprehension rate of their efficiency. The efficiency evaluation is implemented mostly only on the 1st and 2nd level (the reaction level and learning level). However, in a responsible approach to the efficient use of financial means invested into the training process also a shift of evaluation on the 3rd and 4th level (transfer to the work-place level and business result level) and ROI are necessary

CFD Simulation of Turbocharger Regulating Mechanism

Cílem této diplomové práce je zpracovat rešerži na téma regulace turbodmychadel a za pomoci CFD simulace analyzovat silové zatížení lopatek VNT mechanizmu turbodmychadla Garrett při uvažování dvou totožných modelů s rozdílnou hustotou výpočetní sítě. Úvod se zabývá významem přeplňování u vozidlových motorů a druhy plnících agregátů. Vlastní text práce se skládá ze dvou částí. V první části je zpracována rešerše, kde je popsán základní princip přeplňování, konstrukce turbodmychadla a možnosti regulace plnícího vzduchu. Praktická část diplomové práce řeší silové zatížení VNT mechanizmu, kdy bylo zapotřebí optimalizovat 3D model turbodmychadla Garrett, vytvořit dvě výpočetní sítě s různou velikostí elementů, zadat okrajové podmínky výpočtu a analyzovat získané výsledky obou případů. Závěr obsahuje celkový popis problematiky řešené v této diplomové práci, porovnání výsledků silového zatížení lopatek VNT mechanizmu a navrhnutí zjednodušení a ověření celého CFD výpočtu.The aim of this thesis is to provide research into turbocharger regulation, and analyze the force load of vanes in the VNT mechanism of Garrett turbocharger by CFD simulation. In the thesis there is one model with two different mesh densities. It describes the relevance of supercharging vehicle engines and the kinds of supercharging aggregates in the introduction. Then, the thesis is divided into two chapters. The first chapter provides research, describing primary principle of supercharging, turbocharger construction and kinds of air regulation. The practical part of the thesis solves the force load of VNT mechanisms. It was necessary to optimalize the 3D Garrett turbocharger model, create two meshes with different element densities, specify boundary conditions and analyse the results of both cases. A general description of solved problems, comparison of results of force load vanes and propose simplifying and verifying the CFD calculation are included in the conclusion.