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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Fuktproblem i produktionsskedet : Förebyggande åtgärder och åtgärder efter fuktskada

Andersson, Jasmine, Mård, Oliver January 2023 (has links)
Purpose: The purpose of this study is to examine the problems that occur due to moist in the workplace, as well as the measures that can be taken and which measures are most effective. The study will examine the material storage and how it is being handled in the workplace, exploring what directives the insurance companies have, so the insurance is valid. Lastly the study will compare the different measures based on an economic perspective, time perspective as well as material savings. Method: This study is based on a literature study and a case study. The case study is based on both an interview and a site visit. Information has been gathered from various sources such as books, previously made thesis and various governments websites. The case study for this thesis is conducted at Emausskolan in Västerås. Results: To ensure that the moisture management in the production is good a certified moisture expert is hired. Moisture on materials can be prevented by using just-in-time deliveries and the most optimal solution a weather protection. Directives from the insurance companies regarding moisture management at the workplace and what the entrepreneur is obligated to do after moisture damage has occurred. To minimize moisture and mold growth the workplace should be clean and dry. Self-monitoring and samples were carried out throughout the project to ensure that the work has been performed correctly. Conclusions: The conclusion for this thesis is that challenges for moisture depends on the weather, carelessness, and time pressed schedules. Solutions would be to have a tight climate shell, usage of weather protection and surface treatment on materials. Handling of materials is to a certain degree taken care of in terms of palletized and packaged but not always.
42

Structure and regeneration of old-growth stands in the engelmann spruce - subalpine fir zone

Klinka, Karel January 1998 (has links)
Old-growth stands are important for management, conservation, wildlife, recreation, and maintaining biological diversity in forested landscapes. However, we are lacking the information needed to adequately identify and characterize old-growth stands. This is especially true for high elevation, interior forests. The characterization of stand structure and regeneration pattern will help in the development of site-specific guidelines for identifying old growth stands and restoring some of the old-growth characteristics in managed stands. This pamphlet presents a synopsis of a study investigating stand structure and regeneration of old-growth stands in the Moist Cold Engelmann Spruce - Subalpine Fir (ESSFmc) Subzone near Smithers, B.C. The three stands selected for the study were located on zonal sites, each in different watersheds, and the stands were established after fire. The criteria used for selection were: i) absence of lodgepole pine, ii) presence of advanced regeneration, and iii) abundant snags and coarse woody debris. These stands were presumed to represent the old-growth stage of stand development or the final (climax) stage of secondary succession.
43

Vėdinimo įrenginių su integruotais šilumos siurbliais projektavimas, tyrimas ir analizė / Design, Research and Analysis of Air Handling Units with Air Source Heat Pumps

Bareika, Paulius 20 June 2013 (has links)
Magistro baigiamajame darbe nagrinėjami vėdinimo įrenginiai su integruotais šilumos siurbliais. Darbe atliekama tokios rūšies įrenginių literatūros apžvalga. Apžvelgiami šilumos siurblio komponentai, darantys didžiausią įtaką jo darbui. Darbo metu atlikti įrenginių projektavimo ir konstravimo darbai. Pateikiamos projektavimo rekomendacijos. Lyginami skirtingi kompresorių galios moduliacijos principai. Nagrinėjami įrenginių darbo režimai, kylančios problemos eksploatacijos metu, ieškomi problemų sprendimų būdai. Pateikiamos kintamo sukimosi greičio kompresorių galių moduliacijos ribos. Atliekamos energinė ir ekserginė analizės pagal eksperimentinio bandymo duomenis. Nustatomi realūs termodinaminio efektyvumo ir naudingumo koeficientai. Jautrumo analizės metu atliekami elektrinio šildytuvo efektyvumo ir naudingumo skaičiavimai. Pateikiami rezultatai, išvados ir rekomendacijos tokios rūšies įrenginių tobulinimui ir tolimesniam vystymui. Darbo apimtis – 94 psl. teksto be priedų, 66 iliustr., 7 lent., 43 bibliografiniai šaltiniai. / Master's thesis examines air handling units with integrated air source heat pumps. Literature review about this type of units was carried out. An overview of mostly important heat pump‘s components are given. Thesis was an opportunity to design, construct and analyze these units. Different heat pump‘s operation modes examined and main issues turned out. Based on experimental data variable speed compressor's capacity modulation results defined. Moist air thermodynamic calculations have been made and air handling unit with integrated air source heat pump experimental energy and exergy efficiency was defined. Sensitivity evaluation changing heat pump with electric heater carried out. The main recommendation provided for units designing and further development. Thesis consist of 94 p. text without appendixes, 66 pictures, 7 tables, 43 bibliographical entries.
44

Interface entre arquitetura bioclim?tica e decis?es projetuais

Rangel, Pollyana de Faria 16 December 2008 (has links)
Made available in DSpace on 2014-12-17T13:56:58Z (GMT). No. of bitstreams: 1 PollyanaFR.pdf: 9314419 bytes, checksum: 79ef1b1545cd4d9af2a782b4dd572f78 (MD5) Previous issue date: 2008-12-16 / This research has as its object study focus bioclimatic in architecture and its conection with projects decisions, on what regards to environmental comfort for single-family dwelling. From the analysis of five architectural projects inserted in Natal/RN, warm-moist weather, this research gather informations regarding architectural features guided by shape and space arrengement, which embody important elements for the project design development. Computer simulations assisted as foundation to verify the efficiency grade for these projects strategies from shading analysis. Related strategies for the demands of natural ventilation circulation and thermal mass for refrigeration were analysed as well. Results show that there is an hierarchizing of priorities for the decisions made when it comes to shape and space disposition variables, as well as the way these variables will consider the bioclimatic demands. The analysis, even, show that there is no single way to respond to specific bioclimatic demands, as it points out the value of examination of the projectual solutions throughtout the conception process, in order to achieve an efficient project performance for the envimonment comfort / Esse trabalho tem como objetivo estudar o enfoque bioclim?tico em arquitetura e sua rela??o com as decis?es projetuais, no que se refere ao conforto ambiental em habita??es unifamiliares. A partir da an?lise de cinco projetos inseridos em Natal/RN, clima quente-?mido, a pesquisa levanta informa??es sobre as caracter?sticas arquitet?nicas norteadas pela forma e pelo arranjo espacial, os quais englobam elementos importantes para o desenvolvimento do projeto. Simula??es computacionais serviram de base para verificar o grau de efici?ncia das estrat?gias projetuais a partir da an?lise do sombreamento. Foram analisadas tamb?m estrat?gias relacionadas ?s demandas de ventila??o natural e de massa t?rmica para resfriamento. Os resultados demonstram que h? uma hierarquiza??o de prioridades nas decis?es tomadas quanto ?s vari?veis forma e arranjo espacial, e quanto ? maneira de como essas vari?veis ir?o atender as demandas bioclim?ticas. As an?lises evidenciam, ainda, que n?o h? uma ?nica maneira de responder a demandas bioclim?ticas espec?ficas, assim como apontam para a import?ncia de verifica??o das solu??es projetuais durante todo processo de concep??o, a fim de obter um projeto com desempenho eficiente para o conforto ambiental
45

Matematický model membránové destilace / Mathematical Model of Membrane Distillation

Hvožďa, Jiří January 2021 (has links)
Diplomová práce se zabývá membránovou destilací, především z matematické perspektivy. Jedná se o tepelně poháněný separační proces, ve kterém se pro rozdělení kapalné a plynné fáze používá porézní membrána. Kapalina se vypařuje a její plynná fáze prochází přes póry v membráně. Během tohoto procesu dochází k tepelné i látkové výměně, které jsou popsány systémem parciálních diferenciálnich rovnic. Další model je založen na analogii s elektrickými obvody, zákonu zachování energie, hmotnostní bilanci a empirických vztazích. Je ověřen s experimentálně naměřenými daty z nové alternativní destilační jednotky používající membránu a kondenzátor z polymerních dutých vláken. Výkon a účinnost jednotky jsou vyhodnoceny. Další možná vylepšení jsou navržena.
46

Klimatizační komora pro zpracování uzenin / Desing of a processing chamber for smoked goods production

Čermák, Lubomír January 2009 (has links)
The aim of the diploma thesis is to design a drying chamber for meat/salami processing. The design itself comes after the necessary information regarding meat drying and curing has been given. The chamber comprises a main frame, stainless steel chamber, chain conveyor, powertrain and a ductwork for the air treatment. All the parameters of moist air are given as calculated for the states encountered during the drying process, i.e. air dehumidification, when passing the cooling coil, and heating. The control system to meet the required environment condition is also suggested.
47

Zvýšení výkonu mikroturbíny pracující v nepřímém oběhu / Increased power microturbines operating in indirect circulation

Polák, Luboš January 2012 (has links)
Turbogenerator unit 100B TGU, produced in the First Brno Engineering Velká Bíteš a.s., works in Brayton indirect circulation. The aim of this work is the proposal to increase performance levels of technological unit in which the micro-turbine is applied. The work presents various ways to increase performance and efficiency of circulation. The possible options are compared with each of the technological and economic terms. Based on these criteria was selected variant feeding additional water into the circulation. For this design was the work of a mathematical model based on, which was established as the economic balance of the selected variants. The thesis also proposes a technological scheme, which is already incorporated the selected variant and an outline of the verification tests.
48

Vyrovnání provozních dat v energetických procesech / Data reconciliation of energy processes

Nováček, Adam January 2015 (has links)
This thesis is focused on problem data reconciliation of measurements. The objective of this thesis was reconciled measured value from electric drum dryer to suit exactly to the mathematical model of drying. For solution was used nonlinear data reconciliation with constrained nonlinear optimization. The entire calculation is processed in programme MATLAB and outputs are graphs of reconciled values of measurement on dryer such as inlet and outlet temperature and humidity, differential pressure of exhaust moisture air, weight of laundry, atmospheric pressure and electric supply. Achieved solution can by characterized by an amount of evaporated water. Weight of wet and dry laundry are 27,7 kg a 17,7 kg. The calculated amount of evaporated water from measurements was almost 18,8 kg. With reconciled measurements it was 9,7 kg. Goals of the thesis were found more realistic values.
49

Vegetation ecology of Drakensberg foothill moist grassland on Hlogoma Mountain, Underberg, KwaZulu-Natal

Berruti, Sharron Marion 11 1900 (has links)
Hlogoma Mountain is a small inselberg surrounded by farms and commercial forestry in the Underberg district (KwaZulu-Natal) within the Gs10 Drakensberg Foothill Moist Grassland. As little is known about the vegetation on Hlogoma, a survey was undertaken to classify, map and describe the plant communities occurring on the inselberg. A total of 100 (16 m2) randomly stratified sample plots were placed in homogeneous vegetation units within the 117 ha study area. A TWINSPAN classification, refined by Braun-Blanquet procedures, resulted in the identification of two major communities, five communities, 12 sub-communities and four variants. All communities were described and a vegetation map constructed. Ordinations identified key environmental variables that have an impact on the vegetation at the study site. A plant species checklist was created and analysed for floristic composition; rarity and threatened species; medicinal plants; endemism; phenology; flower colour and elevation range; species richness and plant community biodiversity. A total of 467 species were identified, represented by 271 genera and 87 families. Four Red Data species and a new Aspidoglossum species were discovered. Two near-endemic genera, two endemic species and 88 near-endemic species belonging to the Drakensberg Alpine Centre were found on Hlogoma. This study showed that Hlogoma Mountain is an inselberg with high plant species richness and endemism, and is a refuge of conservation importance for biodiversity. / Environmental Sciences / M. Sc.(Environmental Science)
50

Forest fire dynamics and carbon stocks in different ecological zones of Ghana

Nindel, Sandra 30 August 2018 (has links)
Fires occur in most forest reserves in Ghana. However, there is a limited understanding of the fires and their behaviour in the different ecological zones. Therefore, this research was to analyze the spatial and temporal distribution of fires, examine the driving factors, direct and underlying causes and impacts of the fires, determine and compare the fuel dynamics to predict fire behaviour and estimate the effects of fire on carbon stocks in different ecological zones of Ghana. The research used different methodologies including questionnaires, fire records, satellite fire data from MODIS (2001 to 2015) (first approach) and field experiment (second approach). A total of 304 respondents was sampled for eight communities, two communities each around the moist and dry semi-deciduous forest, upland evergreen forest and savanna. The spatial distribution of fire showed a trend along the forest boundaries, open vegetation, degraded areas, human settlements, shrubs, farms, rivers and roads. The temporal trend was significant in the dry forest (435 hotspots), followed by the savanna (229 hotspots), moist forest (76 hotspots) and the least in the evergreen forest (5 hotspots). The fires were observed from August, October to May with the dry forest having the longest seasonality. Sunday, Tuesday and Thursday were the peak days of the detected fire hotspots in the dry, moist and savanna respectively. Most of the fires in the different ecological zones peaked from 13 to 14 pm. The results of the research also revealed that the fires were driven primarily by socioeconomic factors which were supported by environmental, type of vegetation and cultural factors. In all the ecological zones, fires were originating from humans. The study pointed out three categories of human-caused fires through activity (farming), non-activity (carelessness or negligence) and others (unknown causes). The major underlying causes of fire mentioned were the inadequate management of the forest and weak compliance and enforcement of forest laws. All these fires have resulted in several impacts in the various ecological zones. Concerning the fuel dynamics, the total downed woody fuel load in the evergreen forest was found to be higher (228 and 208.4 tonnes per hectare). The litter and duff density (112.2 kilogram per cubic meter) in unburned area and loading (6.3 and 13.5 tonnes per hectare) for both burned and unburned area respectively were significantly greater in the moist forest. Also, the dry forest showed 2.4 tonnes per hectare of herbaceous loading in the burned area. However, fires were predicted to be severe in the savanna regarding the surface rate of spread, flame length and fireline intensity, but with low reaction intensity and heat per unit area. The total amount of aboveground tree carbon, aboveground non-tree and belowground root for both burned and the unburned area varied under the different ecological zones. The highest was seen in the moist forest with the emission of 294 tonnes of carbon per hectare accounting for 82% losses. This research has brought out the current situation of fire in the various ecological zones for the implementation of necessary actions for the future.

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