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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.
91

Kemisk karaktärisering samt nedbrytning av process- och avloppsvatten vid SCA Ortvikens pappersbruk / Chemical characterization and degradation of oxygen demanding compounds in process- and wastewater at SCA Ortviken's paper mill

Blixt, Ann January 2006 (has links)
During pulp and papermaking process a huge amount of water is used. The wastewater contains a large amount of pollutants and has to be treated before it reaches the recipient. In March 2004 a new bleaching plant was started up at SCA Graphic Sundsvall AB, Ortviken’s paper mill using peroxide. The production of bleached thermo mechanical pulp and thus the load to the wastewater plant increased. During bleaching substances dissolve from the pulp and the amount of COD in the wastewater increase. To keep the efficiency of chemical and biological oxygen demand (COD, BOD) removal, the aerated lagoon is supplied by liquid oxygen. In November the same year a new pre-step including a pre-aeration, carrier and selector step was added to the existing wastewater plant. The COD-loading to the lagoon decreased and the supply of liquid oxygen was reduced. This master thesis has been carried out at SCA Graphic Research AB, Sundsvall. The aim was to chemically characterize the wastewater with focus on the composition of carbohydrates, lignin and extractives and its influence on the biodegradability. Measurements have been carried out on total samples, suspended solids, colloidal and dissolved substances using GF/A and ultra filtration. Measurements were performed on process water from the bleaching plant and on water during the wastewater treatment process. The results show that the chemical composition of dissolved substances has a larger impact on the biodegradability than the total amount of COD. A large amount of lignin will make the wastewater harder to degrade. Suspended solids have lower biodegradability compared to the dissolved fraction. Analyzes of suspended material from the bleaching plant show a relative composition of around 41 % lignin. Analyzes done before on the dissolved fraction show a composition of 29 %. It seems that a larger amount of lignin is represented in suspended solids compared to the dissolved fraction. This can explain the low biodegradability, combined with the theory that the suspended solids are less accessible for the microorganisms. To reduce the outgoing COD the incoming flow of dissolved lignin and suspended solids to the active sludge plant has to decrease. COD in the outgoing wastewater to the recipient consists of around 90 % lignin. Extractives as saturated fatty acids, palmitic and stearic acid plus lignans (which is interpreted as a byproduct from lignin degradation) do not degrade remarkable during wastewater treatment. Flocculation of COD is one way to reduce the discharge to the recipient. Addition of 2,6 g/l PAX-18 (a high charged aluminum complex) to the wastewater from the bleaching plant gives a reduction of 40 % COD and 50 % lignin in laboratory scale and it is recommended to study further. Time related studies of BOD show that the microorganisms need five days to degrade organic material and the hydraulic retention time in the aerated lagoon has to be guaranteed. / Vid massa- och pappersframställning åtgår stora mängder vatten. Det processberörda avloppsvattnet innehåller mycket föroreningar varför det måste renas innan det släpps ut till recipienten. I mars 2004 startades ett nytt väteperoxidblekeri vid SCA Graphic Sundsvall AB, Ortvikens pappersbruk varvid produktionen av blekt termomekanisk massa ökade och den biologiska reningen belastades hårdare. Blekning löser ut vedämnen från massan och bidrar således till ökad mängd syreförbrukande ämnen i avloppet. För att upprätthålla reduktionen av syreförbrukande ämnen (COD, BOD) tillförs ren syrgas till den luftade dammen. I november samma år utökades den externa reningsanläggningen med ett biologiskt försteg, en s.k. multibioanläggning bestående av ett frisimmarsteg, ett bärarsteg samt ett selektorsteg. COD-belastningen in till den luftade dammen minskade och tillförseln av ren syrgas kunde reduceras. Examensarbetet har utförts vid SCA Graphic Research AB, Sundsvall med syftet att kemiskt karaktärisera avloppsvattnets sammansättning av kolhydrater, lignin och extraktivämnen och dess inverkan på vattnets grad av biologisk nedbrytbarhet. Analyser har gjorts på totalprov, suspenderande ämnen samt kolloidalt och löst material via fraktionering med hjälp av GF/A- och ultrafiltrering. Analyser gjordes dels på processvatten från blekerierna och dels på avloppsvatten under reningsprocessen. Resultaten visar att den kemiska sammansättningen hos löst material har större inverkan på avloppsvattnets grad av nedbrytbarhet än den absoluta halten av syreförbrukande ämnen. En hög andel lignin ger ett mer svårnedbrytbart vatten. Suspenderat material är vidare mer svårnedbrytbart än de lösta fraktionerna. Analys av suspenderande substans hos blekpressat visar att andelen lignin är omkring 41 % medan arkiverade analysresultat på den lösta fasen visar ett innehåll på omkring 29 %. Det tyder alltså på en betydligt högre andel lignin i den partikulära fasen jämfört med den lösta, vilket i kombination med att materialet inte är lika lättillgängligt för mikroorganismerna kan förklara den låga bionedbrytbarheten. Om COD-utsläppet ska minskas bör inkommande flöde av löst lignin och suspenderande substans till den biologiska reningen reduceras. COD-halten i utgående avloppsvatten till recipienten utgörs av omkring 90 % lignin. De extraktivämnen som inte bryts ned är mättade fettsyror, exempelvis palmitin- och stearinsyra samt lignan, vilket antas bildas som restprodukt vid degradering av lignin. Flockning av syreförbrukande ämnen är ett sätt att gå till väga för att minska utsläppet av dessa till recipienten. Genom tillsats av 2,6 g/l PAX-18 (ett högladdat aluminiumkomplex) till blekeriavloppet kunde 40 % COD och 50 % lignin reduceras. Flockningsförsöket är gjort i laboratorieskala vid rumstemperatur och ytterligare utvärdering rekommenderas. Tidsstudier av BOD visar att mikroorganismerna behöver fem dagars uppehållstid för att hinna bryta ned organiskt material i avloppsvattnet, varför omloppstiden i den luftade lagunen inte bör understiga denna tidsrymd.
92

Assessing CSR and Applying Social Life Cycle Assessment: A case study on Biochemical Oxygen Demand Online Monitor

Wan, He January 2012 (has links)
Wuhan China and Borlänge Sweden collaborate to promote sustainable business growths. This thesis, being part of sustainable business project, aims to understand how business can contribute to sustainable development and explore mechanisms of social life cycle assessment. In an effort to answer research questions and further to achieve the general purpose, a BOD online monitor case study is described and analyzed by applying both qualitative and quantitative approaches. Data collection is based on interviews and documents. In the case of BOD online monitor, the thesis identifies Boffin and Universtar companies’ CSR levels. It also observes that SLCA method is able to discover Boffin and Universtar’s social performances at life cycle impact assessment stage and disclose online monitor’s social impacts at interpretation stage. The thesis finally concludes that business’ CSR level can be evaluated from three dimensions: companies’ goals on conducting business, business operation performances and resolved problems. SLCA method is able to disclose enterprises’ social performances, discover underlying factors that might hinder corporations’ ability to contribute to sustainable development and improve product’s social at the same time.
93

The relationship between exercise, amenorrhoea, percentage body fat and disordered eating among adolescent female runners / T. Botha

Botha, Tershia January 2008 (has links)
Thesis (M.A. (Human Movement Sciences))--North-West University, Potchefstroom Campus, 2008.
94

The relationship between exercise, amenorrhoea, percentage body fat and disordered eating among adolescent female runners / T. Botha

Botha, Tershia January 2008 (has links)
Thesis (M.A. (Human Movement Sciences))--North-West University, Potchefstroom Campus, 2008.
95

Chladová odolnost hladinatky Velia caprai: vliv aklimace a věkové třídy na bod podchlazení / Cold resistance of the water cricket Velia caprai: the influence of acclimation age class and food availability on the supercooling point

NOVOTNÁ, Iveta January 2012 (has links)
Recently, the cold resistance becomes a common topic in scientific articles. If we focus on order Heteroptera, we can find a lot of studies dealing with the cold resistance or with the supercooling point (SCP) and also with the factors that influence them. According to the general rule, the acclimation at low temperatures increases the cold resistance. Therefore, the main goal of this thesis is to find out, whether the acclimation also increases the cold resistance of the water cricket Velia caprai Tamanini, 1947 (Veliidae), with the intention to measure SCP of the water crickets depending on the acclimation temperature and the length of exposure. Due to the high mortality (the 284 individuals remained alive of total 1300) and due to the technical difficulties in measuring of SCP (measured only 36 individuals) it was necessary to modify the original goal of the thesis. The new goal was to test the influence of acclimation (during one month vs. one week) and the influence of different temperatures (0°C, 5°C, 10°C) on SCP of V. caprai. The individuals used for this measurement were collected during the year 2010 and in March 2011. The results of this thesis did not confirm the hypothesis that the acclimation at low temperatures increases the cold resistance. The individuals who were acclimated at a higher temperature have the values of SCP demonstrably lower than the individuals who were acclimated at low temperatures. The individuals who overwinter for the first time have arguably higher cold resistance than the individuals who overwinter for the second time. Probable cause of these results is the fact that the water cricket V. caprai does not start with diapause in the fall but it overwinters in quiescence.
96

Hodnocení efektivnosti vybraného investičního projektu, včetně výběru optimálního způsobu financování. / Evaluation of the effectiveness of the selected investment project, including the selection of the optimal method of financing.

KOČOVÁ, Lenka January 2013 (has links)
This work discusses about issues of investment decision, which is crucial for every business. The aim of this thesis was to evaluate the effectiveness of selected investment project. To assess the potential of this investment, was necessary to assess the current status, whether the enterprise has enough resources to finance this intensive investment. Whether the project is not associated with an increase in the financial risk of the company. Then were identified revenues and expeditures of the project.It was finally in the evaluation of the effectiveness of investments carried out an analysis of the risk of the project.
97

Estimativas das exigências de lisina de frangos de corte pelos métodos dose resposta e fatorial

Siqueira, Jefferson Costa de [UNESP] 18 August 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-18Bitstream added on 2014-06-13T20:45:12Z : No. of bitstreams: 1 siqueira_jc_dr_jabo.pdf: 879860 bytes, checksum: 0bbdea44a6c2523dc3a29d105184e7a2 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / As exigências de lisina de frangos de corte vêm sendo estudadas por décadas pelo método dose resposta, contudo, as recomendações são amplamente contrastantes. Assim, cresce o interesse pela elaboração de modelos capazes de predizer as exigências de aves de diferentes genótipos e idades mantidas sob diferentes condições de criação. Os objetivos deste trabalho foram: (1) padronizar um método para estimar as exigências de lisina digestível para mantença; (2) comparar as respostas de frangos de corte alimentados com dietas formuladas pelas técnicas da suplementação dos aminoácidos e da diluição das dietas; (3) estimar as exigências de lisina digestível de frangos de corte nas fases pré-inicial (1 a 8 dias), inicial (8 a 22 dias), crescimento (22 a 35 dias) e terminação (35 a 42 dias) pelo método dose resposta; (4) elaborar modelos para estimar as exigências de lisina digestível de frangos de corte com base no método fatorial. Concluiu-se que: (1) ensaios de metabolismo com alimentação controlada pelo peso metabólico são satisfatórios para determinar as exigências de lisina para mantença; (2) a técnica da diluição das dietas favoreceu o desempenho das aves, exceto na fase de crescimento, sendo recomendada para a formulação de dietas experimentais; (3) frangos de corte Cobb 500 exigem níveis de lisina digestível de 1,361; 1,187; 1,073 e 0,916% nas fases pré-inicial, inicial, crescimento e terminação, com base no método dose resposta; (4) os modelos foram capazes de predizer as exigências de lisina de frangos de corte de diferentes linhagens e idades, sugerindo a redução dos níveis de lisina digestível após a segunda metade do ciclo de produção. / The lysine requirements of broiler chickens have been studied for decades by the dose response method, however, the results of different studies are widely contrasting. In this sense, the growing interest in the development of models capable of predicting the requirements of birds of different genotypes reared under different conditions. This work aimed: (1) standardize a method to estimate the lysine requirements for maintenance, (2) compare the responses of broilers fed diets formulated based on the supplementation technique and the dilution technique , ( 3) estimate the lysine requirements of broilers during pre-starter (1 to 8 days), starter (8 to 22 days), growth (22 to 35 days) and finishing (35 to 42 days) phases, by dose response method, (4) develop models to estimate the digestible lysine requirements for broiler chickens based on the factorial approach. It was concluded that: (1) metabolism assay with diets controlled by metabolic weight are satisfactory to determine the lysine requirements for maintenance, (2) the dilution technique was superior to the supplementation, except in the growth phase and is recommended to evaluate lysine requirements of broilers, (3) Cobb 500 broiler chickens require levels of lysine to 1.361, 1.187, 1.073 and 0.916% during the pre-starter, starter, growth and finishing phases, estimated by dose response method; (4) the models developed were able to predict the digestible lysine requirements of broilers of different strains and ages, suggesting the reduction in digestible lysine levels after the half of the production cycle.
98

Field Development and Performance Evaluation of a Constructed Wetland System in the Tropics

Hummel, Adelaide Pereira 08 November 2013 (has links)
This study is part of a project that was conducted by Florida International University (FIU), which designed, built, and characterized a constructed wetland (CW) wastewater treatment system in El Salvador, Central America. This study focuses on the detailed performance of a field-scale CW in the tropics, consisting of a subsurface flow wetland (SSF) and a surface flow wetland (SF). The SSF had a total area of 151.2 sq. m., filled with gravel and planted with Phragmites, Thalia, and Brachiaria, along three independent cells operating with a flow in parallel and receiving the influent domestic wastewater from a facultative lagoon and preceded the SF. The SF was a shallow open basin containing alternating regions of open water (195 sq. m. total) with submerged aquatic plants (Elodea) and regions of shallower water (605 sq. m. total) filled with emergent wetland vegetation (Typha, Thalia, and Cyperus). The design, construction, startup and operation phases of the field scale CW in that tropical setting are thus described with detail, including both SSF and SF characterization of influent and effluents. The SSF average hydraulic detention times during the wet and dry season were 2 days ± 0.9 days and 4 days ± 0.4 days, respectively; and the SF average hydraulic detention times during the wet and dry season were 20 days ± 11.1 days and 77 days ± 19.5 days, respectively. Brachiaria/Cyperus presented better results during the wet season with average BOD5 residuals of 36% ± 25%, and Thalia/Thalia during the dry season with average BOD5 residuals of 33% ± 22%. Phragmites/Typha presented better results during both seasons with average TSS residuals of 2% ± 3% (wet season), and 2% ± 2% (dry season). Residuals are also presented for COD, Oil & Grease, Total Fecal Coliform, Total Phosphorus, and Total Nitrogen. In addition, an assessment of the empirical models used in the design of the system is completed, having the EPA methodology as the preferred for BOD5 removal and three methodologies for TSS removal under tropical climate conditions. A comparison of the differences in treatment associated with each one of the selected plants and their combinations is also discussed. In summary, results strongly suggest that the CW system can effectively reduce contaminants in wastewater to levels that are comparable with the objective levels (i.e., secondary treatment levels).
99

Antecipação da idade à cobertura de novilhas leiteiras, recriadas a pasto, suplementadas com minerais orgânicos e inorgânicos

Drubi, Gabriel Miranda [UNESP] 13 August 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-13Bitstream added on 2014-06-13T20:37:13Z : No. of bitstreams: 1 drubi_gm_me_jabo.pdf: 355513 bytes, checksum: 63976bb3a15c3a53adc09328561abedb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram realizados dois experimentos visando avaliar a suplementação mineral em novilhas leiteiras criadas a pasto. No primeiro, buscou-se avaliar o efeito da suplementação com fontes de minerais inorgânicos e orgânicos no período da águas sobre o desenvolvimento corporal de novilhas mestiças Gir x Holandês, com idade média de 13 meses e peso vivo médio inicial de 176,81± 10,1 kg, distribuídas em delineamento em blocos casualizados, com dezesseis repetições por tratamento, totalizando 32 animais no período das águas. As novilhas permaneceram em pastagem de Brachiaria brizantha cv. Marandu e como tratamento utilizou-se suplementação com minerais inorgânicos ou orgânicos. Os animais foram manejados em sistema de pastejo intermitente, com sete dias de ocupação e 35 dias de descanso em cada piquete. Ao final de cada ciclo de pastejo (42 dias) os animais foram pesados e mensurados quanto a altura na cernelha e o perímetro torácico e o peso médio do lote usado para os cálculos de ajuste de carga. A disponibilidade de forragem foi monitorada semanalmente. Não foram observados efeitos das fontes de minerais inorgânicos e orgânicos sobre o ganho médio diário de peso vivo (GMDPV) e nas mensurações do perímetro torácico e na altura na cernelha. O ajuste da carga animal na pastagem durante o período das águas e com a suplementação mineral correta proporcionando bom desempenho das novilhas com ganho de (0,68 kg/dia). No segundo experimento, objetivou-se avaliar o efeito de dois níveis de suplementação com fontes de minerais inorgânicos e orgânicos no período da seca sobre o desenvolvimento corporal e desempenho reprodutivo de novilhas mestiças Zebu x Holandês, com idade média de 19 meses e peso vivo médio inicial de 302,70 kg, distribuídas em delineamento inteiramente casualizado em esquema fatorial 2 x 2 (minerais x níveis) com cinco repetições... / Two experiments have been carried out. The first one, during the rainy season, evaluated the effects of the mineral supplementation with organic and inorganic sources, on the performance of 32 Gir x Holstein (GH) crossbred heifers, averaging 13 months of age and an average initial liveweight (LW) of 176,81kg . They were kept in Brachiaria brizantha (Hochst. Ex A. Rich.) cv. Marandu pasture under rotational grazing system, with 7-day occupation and 35-day rest. The forage utilization didn’t vary between treatments, averaging 12Kg MS/100 Kg (LW). The average stocking rate (SR) was 4,19 AU/ha. It hasn’t been observed any effects of the mineral sources on the average daily gain (ADG), thoracic perimeter and shoulder height, which were averaging 0,68 Kg/day; 44,47 cm and 55,30 cm, respectively. The mineral supplement intake was 58,10 g/animal/day (inorganic source) and 57,12 g/animal/day (organic source). The second experiment aimed at evaluating the effects of two supplementation rates (2,5 and 5,0 g/Kg of LW) making use of mineral sources, inorganic and organic, during the dry season, on the performance of GH crossbred heifers, averaging 19 months of age and average initial liveweight (LW) of 307,75 Kg. The forage utilization didn’t differ between treatments, averaging 12kg MS/100Kg LW. The average stocking rate (SR) was 2,33 AU/ha. The average supplement intake was 0,86; 1,70; 0,81 and 1,75 Kg/animal/day, for inorganic source (2,5 g/Kg and 5,0 g/kg LW) and for organic source (2,5 g/Kg and 5,0 g/Kg LW), respectively. It hasn’t been observed any influence of the mineral sources on the average daily gain (ADG) of the heifers, however it has been observed an impact on the supplementation rate, where the heifers supplemented with 5,0 g/Kg of LW presented a higher average daily gain ADG (0,48 Kg/animal) in comparison to the ones supplemented with 2,5 g/kg of LW (0,37 Kg/animal).
100

Náklady a změna objemu výroby / Costs and change of production volume

HOREJŠOVÁ, Kateřina January 2011 (has links)
Thesis deals with the relationship of costs and change of production volume. The introduction is characterized by the selected company from South region and in terms of profit, the number of employees and total assets. It is also shown changes in costs, revenues and operating results. There are also counted pointer to speak about cost-effectiveness in business. For example, operating leverage, break-even point, profitability ratios, cost ratio. From the calculations it is clear that the best business results achieved in 2007, while the worst of the venture was in 2008.

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