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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.
1

Moorland vegetation history and climate change on the North York Moors during the last 2000 years

Chiverrell, Richard Christopher January 1998 (has links)
A history of vegetation and climate change during the last two millennia is elucidated from ombrogenous blanket peat sequences from the central and eastern North York Moors. The evidence is derived from five mires Harwood Dale Bog, May Moss, Fen Bogs, Yarlsey Moss and Bluewath Beck. May Moss received particular attention because it is the only remaining unmodified blanket mire on the North York Moors. All the sites were cored, with May Moss yielding seven cores, four of which were extruded along a five metres transect. The cores were selectively analysed for plant macrofossil, testate amoebae, humification and pollen. Chronologies were constructed using 14C dating and the judicious use of biostratigraphic marker horizons. Comparison of 14C dates obtained on bulk peat samples and on pure Sphagnum remains encountered substantial differences, which raises anxieties about 14C dating of a material as heterogeneous as peat. The regional vegetation history elucidated from the pollen evidence reflects changes in the demography, culture, economy and climate of the North York Moors. Evidence of woodland decline and abundant agricultural taxa are attributed to phases of increased agricultural exploitation of the uplands in response to a commercial approach to farming during the Romano-British period, population expansion during the Anglo-Scandinavian period, and attempts to exploit the moorlands during the boom periods of the 12th-13th and 15th-16th centuries. Conversely, phases of woodland expansion and agricultural decline are associated with the Roman withdrawal from England, the 'harrying of the north' in AD 1069-70 and demographic collapse during the 14th century. T estate amoebae, plant macrofossil and humification stratigraphies provide a record of mire palaeohydrology, which is used to infer a history of effective precipitation. There is a broad consistency within the palaeohydrological indications from a single core, which indicates that the techniques support each other. Furthermore, similar testate amoebae, plant macrofossil and humification stratigraphies were encountered in adjacent cores at May Moss. There is evidence of pronounced shifts to wetter/cooler conditions circa 500 BC, AD 450, 850, 1400, 1625 and 1825 separated by unambiguously drier/warmer phases circa AD 200-450, 700-800, 1100-1200, 1550-1600 and 1750-1800. The palaeoclimate time series displays a strong correlation with the record of solar variability; however, biosphere, atmosphere and oceanic interactions in the North Atlantic region and global volcanism also affect regional climate.
2

Filtar som preventiv åtgärd mot iatrogen hypotermi : -En litteraturstudie

Björkegren, Frida, Nilsson, Fanny January 2017 (has links)
Bakgrund: Hypotermi, låg kroppstemperatur, i samband med operation är ett vanligt förekommande problem. För patienten medför hypotermi ett flertal fysiologiska konsekvenser, men kan även bidra till ett försämrat välbefinnande. För att förebygga hypotermi i samband med operation kan passiva och aktiva uppvärmningsmetoder vidtas. Syfte: Syftet med litteraturstudien var att undersöka vilka aktiva och passiva filtar som förebyggde iatrogen hypotermi och medföljande shivering. Metod: Studien gjordes som en litteraturstudie efter sökningar i databaserna PubMed och Cinahl.  Elva randomiserade kontrollerade studier och en kvasiexperimentell studie inkluderades. Resultat: Forced air warming, FAW, var mer effektiv i att öka kärntemperaturen och bevara normotermi postoperativt. FAW var också den mest effektiva uppvärmningsmetod i att minska intensiteten av shivering. Litteraturstudien visar motstridiga resultat om vilken uppvärmningsmetod som var mest effektiv i det intraoperativa skedet. Det fanns ingen signifikant skillnad mellan de olika uppvärmningsmetoderna i att minska incidensen av shivering. Slutsats: Att motverka iatrogen hypotermi är en väsentlig del för patientens välbefinnande. Forced air warming, FAW, var mer effektiv att förebygga hypotermi och minska intensiteten av shivering. Det fanns däremot ingen signifikant skillnad mellan de olika uppvärmningsmetoderna i det intraoperativa skedet eller i att minska incidensen av shivering. Dock är litteraturstudiens omfång begränsad och det krävs därför mer omfattande studier för att uppdatera kunskapsläget och ge patienten den mest lämpade vården. / Background: Hypothermia, low body temperature, is a common problem associated with surgery. For the patient, hypothermia involves a high frequency of physiological consequences, but may also contribute to a reduced wellbeing. In order to prevent iatrogen hypothermia - that is to say hypothermia associated with surgery, passive and active rewarming systems can be used. Aim: The aim of the litterature study was to investigate which rewarming system of active and passive blankets that prevent iatrogen hypothermia with supplied shivering. Method: The study was made as a literature study after a research on the databases PubMed and Cinahl. Eleven randomized controlled studies and a quasi-experimental study were included. Results: Forced air warming, FAW, was the most effective rewarming system in raising the core temperature and maintaining normothermia in postoperative patients. FAW was also the most effective rewarming method in decreasing the intensity of shivering. The literature study also showed contradictory results regarding which rewarming system that was most efficient during surgery. There were no significant differences between the rewarming systems in preventing the incidence of shivering. Conclusions: Preventing hypothermia is an essential part for the patient’s wellbeing. FAW were the rewarming systems that were most efficient in preventing hypothermia and decreasing the intensity of shivering. In contrast, there were no significant differences between the rewarming systems during surgery, nor regarding decreased incidence of shivering. However the range of the literature study is limited and therefore more extensive studies are required to update the state of knowledge to be able to give the most adequate care for the patient.
3

Optimization of Fire Blanket Performance by Varying Radiative Properties

Brent, Kevin M. 30 January 2012 (has links)
No description available.
4

Holocene blanket peat development in south west Scotland : the roles of human activity, climate change and vegetation change

Flitcroft, Catherine Esther January 2006 (has links)
This thesis examines the role of autogenic and allogenic forces in determining the timing and development of blanket peat initiation and how the occurrence and growth of blanket peat subsequently constrains human activities. A number of factors involved in the formation of blanket peat have been defined in the literature, in particular the roles of climate change, soil processes and anthropogenic effects, tested in this thesis from a typical peat-covered upland in south west Scotland. Tests are developed from a multi-proxy approach and by comparing peat-stratigraphic and palaeoecological records from a series of nine 14C dated peat profiles from a single hillside. A detailed examination of the sequence and timing of blanket peat initiation in the Holocene Epoch is presented from a case study from the head of the Glen App valley, Lagafater, south west Scotland. The evidence was taken from a total of nine peat transects at 215m OD, 300m OD and 400m OD where agricultural, hydrological and micro-climatic effects are expected to have differed and had different impacts on soils and vegetation. Samples were retrieved from the top, middle and bottom of a gently undulating slope at each altitude. This has allowed a localised picture of peat initiation to be obtained from each locality and with changes in altitude, allowed for an analysis of the factors responsible up and down slope and the identification of synchronous autogenic forces. A number of analytical techniques have been used. Pollen analysis was undertaken as the principal method of vegetation reconstruction at all sites, particularly through the initiation horizon. Variations in mire-surface wetness, determined through dry bulk density and humification analysis, were also employed to generate a record of probable changes in effective precipitation and the effect these may have had on the accumulation rate of the blanket peat. In order to attempt to answer the question of when blanket peat was initiated and to establish the synchroneity of changes, twenty nine AMS 14C dates were obtained. The evidence suggests that blanket peat developed during the Mesolithic period, through to the early Bronze Age. It substantiates an anthropogenic forcing factor for palaeohydrological changes, with early landscape management and cereal cultivation accelerating the process of blanket peat initiation. With progressive changes in precipitation interacting with factors such as weathering of bedrock and vegetation cover, the local landscape at Lagafater was covered by blanket peat by the early Bronze Age. The radiocarbon chronology obtained from the multi-proxy records allowed the synthesis of these data sets and the definition of Holocene vegetation change, climate change and the history of human impact throughout the early prehistoric era across this landscape.
5

Tratamento de água negra em reator UASB /

Pereira, Maria Beatriz de Oliveira Coelho. January 2016 (has links)
Orientador: Gustavo Henrique Ribeiro da Silva / Banca: Adriana Ferreira Maluf Braga / Resumo: O presente trabalho estudou o tratamento de água negra simulada (esgoto sanitário com efluente suíno) em reator UASB (upflow anaerobic sludge blancket) mesofílico com DQO (demanda química de oxigênio) de entrada de 958,489 ± 489,2mg/L, TDH (tempo de detenção hidráulica) de 1,8 ± 1,8d e COV (carga organica volumética) de 0,2 ± 0,2 KgDQO/m³d. Avaliou-se, ainda, o efeito da suplementação de metais traço (Fe, Ni, Mn, Ba, Se, Co e Cu) na AME (atividade metanogênica específica) do lodo utilizado como inóculo de partida do reator. Os ensaios com metais traços foram realizados em batelada utilizando o método Plackett Burman para planejar o experimento. Foram observados valores nitrogênio amoniacal junto a entrada do reator de 197,37 ± 84,3mgN/L, no entanto, o reator apresentou remoção de DQO de 61,7% ± 15%, demonstrando que não houve efeito tóxico da amônia no meio. Os resultados dos ensaios em batelada demonstraram efeito negativo estatisticamente significativo das adições de Ba e Mn sobre a AME, contudo, o Cu e o Se apresentaram efeito positivo, embora não estatisticamente significativos, indicando que a produção de metano a partir de água negra pode ser estimulada com a suplementação desses metais / Abstract: The present work studied the treatment of simulated black water (sewage with swine wastewater) in UASB (upflow anaerobic sludge blancket) mesophilic with input COD (chemical oxygen demand) of 958,489 = 489,2 mg/L, HRT (hydraulic retention time) of 1.8 = 1.8d and OLR (organic loading rate) 0.2 = 0.2 kgCOD/m3d. This work also evaluated the effect of supplementation of trace metals (Fe, Ni, Mn, Ba, Se, Co e Cu) on the SMA (specific methanogenic activity) of the seed inoculum used in reactor startup. The trace metals assay were performed in batch mode using Plackett-Burman method of the design of the experiments. Despite of the ammonia nitrogen values at the inffluet of 197.37 = 84.3 mgN/L reactor, the reactor, the reactor presented COD removal of 61.7% = 15%, indicating no toxic effectof the addition of Ba and Mn on the SMA of the sludge, however, Cu and Se presented positive effect, although not statistically significant, which indicates that the methane production from black water might be enhanceb by the supplementation of these metals / Mestre
6

Study on the Treatment of Sewage by A Combined Upflow Anaerobic Sludge Blanket (UASB) Constructed Wetland Process

Ma, Chia-Chen 12 July 2005 (has links)
Upflow anaerobic sludge blanket (UASB) has been developed and commercially used for treating high-strength wastewaters since 1971, and this process has been extended its applications to domestic sewage treatment since 1980. Constructed wetlands (CWL) can be treated as a simulated natural treatment system, which use solar radiation as the energy source. By analogy with some removal mechanisms in natural wetlands, constructed wetlands are able to transform and remove pollutants from the wastewater. Other features provided by the constructed wetland include wildlife support, hydrologic modification, erosion protection, and open space and aesthetics. It has been applied for domestic wastewater purification for decades. In this study, a pilot UASB-CWL reactor was built to test its performance for the removal of organic compounds and nutrients from a sewage with COD (Chemical oxygen demand) in the range of 200-300 mg/L. The UASB reactor has an active liquid volume of 2.5 liters and the CWL includes a 56 L-tank (CWL-1) followed by a 80 L-tank (CWL-2) in which emergent macrophyte (reed, Phragmites australis L.) and floating macrophyte (Pistia stratiotes L.), respectively, were planted. Effects of hydraulic retention time (HRT) of the test water in the reactor on the pollutant removal were tested. Results indicate that with HRTs of 2, 45, and 64 hours, respectively, in the UASB, CWL-1, and CWL-2, the system exhibited good performances for pollutant removal. The HRTs are equivalent to CODt loadings of 3.06, 0.065, and 0.026 kg/m3.day to the UASB, CWL-1, and CWL-2, respectively. Average total COD (CODt), soluble COD (CODs), total biochemical oxygen demand (BODt), suspended solids (SS), and phosphate-P (P) were 121, 62, 33, 130, and 0.10 mg/L, respectively, and these are equivalent to the removal efficacies of 45-65, 60-80,65-75, 30-50, and 85-95%, respectively. With the operation conditions, average CODt = 28 , CODs = 18, BODt = 10, SS = 18, NH3-N = 18, NO2--N =12 , NO3--N = 1.0, and P = 0.0 mg/L were obtained, and the average removal total efficacies were 93, 93, 90, 75, 72, 95, and 100%, respectively. Effluent qualities are far superior to the national effluent standards for domestic sewage in Taiwan.
7

Tratamento anaeróbio-aeróbio de águas residuárias de suinocultura e reúso na produção de milho para silagem /

Cangani, Max Ternero. January 2011 (has links)
Resumo: Neste trabalho, avaliou-se o desempenho de dois conjuntos de reatores anaeróbios de fluxo ascendente com manta de lodo (UASB) instalados em série. Os conjuntos I e II foram compostos por dois reatores UASB em série com volumes de 908 e 350 L e de 908 e 188 L, respectivamente. No conjunto II, foi realizado pós tratamento do efluente em um reator operado em batelada sequencial (RBS) com alimentação contínua, com volume de 3000 L. As cargas orgânicas volumétricas (COV) aplicadas no primeiro reator dos conjuntos I e II variaram de 8,36 a 9,95 g DQO total (L d)-1 e de 7,83 a 11,6 g DQO total (L d)-1, respectivamente. As eficiências médias de remoção de DQO total, nitrogênio Kjeldahl (NK), fósforo total (P-total) foram elevadas e variaram de 95 a 97% e de 97 a 99%, de 64 a 67% e de 53 a 69%, e de 80 a 87% e de 71 a 89%, nos conjuntos I e II, respectivamente. As eficiências também foram elevadas para os metais Cu, Fe, Mn e Zn nos conjuntos I e II e variaram de 80 a 91% e de 63 a 80%, de 59 a 80% e de 51 a 72%, de 89 a 97% e de 81 a 98%, de 87 a 98% e de 91 a 99%, respectivamente. A semeadura do milho, foi realizado na safrinha 2009 e na safra 2009/2010, ambos em sistema de plantio direto e convencional, para a confecção de silagem. Os valores do pH observados na silagem não diferiram entre os tratamentos nas duas épocas de semeadura e nos sitemas de plantio direto e convencional. A adubação do milho para confecção de silagem, com dejeto bruto de suíno, com dejetos tratados em sistema anaeróbio e com os dejetos do pós-tratamento, quando comparada com a adubação mineral, não apresentou resultados com diferenças significativas na silagem na maioria dos atributos avaliados. O reúso dos efluentes tratados e do dejeto bruto, não promoveu alterações na nutrição da planta, porém os efluentes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study evaluated the performance of two sets of upflow anaerobic sludge blanket (UASB) installed in series. The sets I and II were composed of two UASB reactors in series with volumes of 908 and 350 L and 908 L and 188, respectively. In set II was conducted after the treatment of the effluent in a sequencing batch reactor (SBR) with continuous flux, with a volume of 3000 L. The volumetric organic loads (VOC) applied to the first reactor of the sets I and II ranged from 8.36 to 9.95 g total COD (L d) -1 and 7.83 to 11.6 g total COD (L d) -1, respectively. The average removal efficiencies of total COD, Kjeldahl nitrogen (NK), total phosphorus (total P) were high and ranged from 95 to 97% and 97 to 99%, 64 to 67% and 53 to 69% and 80 to 87% and 71 to 89% in clusters I and II, respectively. The efficiencies were also high for Cu, Fe, Mn and Zn in clusters I and II, and ranged from 80 to 91% and 63 to 80%, 59 to 80% and 51 to 72% from 89 to 97 and 81% to 98%, 87 to 98% and 91 to 99%, respectively. We carried out the swing of maize in the 2009 off-season and 2009/2010 season, both in no-tillage and conventional sistems for making silage. The pH values observed in the silage did not differ significantly between treatments in both seasons of swing and in the sistems of tillage and no-tillage. The fertilization of corn for silage making, with raw pig manure with waste treated in anaerobic system and the waste from the post-treatment compared to mineral fertilization, results showed no significant difference in silage in most parameters. The reuse of treated effluent and raw manure, did not promote changes in the nutrition of corn but the application of treated effluent increased concentrations of N readily available for plants in soil. Even in much larger doses applied compared to the raw waste, the treated effluent, promoted soil contamination by total coliforms and thermotolerant lower / Orientador: Roberto Alves de Oliveira / Coorientador: Ana Cláudia Ruggieri / Banca: Wanderley José de Melo / Banca: Israel Jose da Silva / Mestre
8

Study on Compatibility of Advanced Materials Exposed to Liquid Pb-Li for High Temperature Blanket System / 高温ブランケットシステムの為の液体リチウム鉛と先進材料の共存性に関する研究

Park, Changho 24 September 2013 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第17916号 / エネ博第288号 / 新制||エネ||60(附属図書館) / 30736 / 京都大学大学院エネルギー科学研究科エネルギー変換科学専攻 / (主査)教授 小西 哲之, 教授 星出 敏彦, 教授 木村 晃彦 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM
9

Clogging of a laboratory simulated landfill drainage blanket

Eisenhart, Bradley A. January 1992 (has links)
No description available.
10

Advanced Undersepage Analyses for Levees

Batool, Abeera 27 November 2013 (has links)
The events of Hurricane Katrina in 2005 prompted the US Army Corps of Engineers (USACE) to commission studies to identify the failure mechanisms of levees and I-walls. This involves updating of the current USACE Engineering Manual (EM) 1110-2-1913, "Design and Construction of Levees," which uses Blanket Theory for seepage analysis. Blanket Theory entails analytical methods for calculating seepage pressures and flows beneath levees. The revision of the manual will address the design seepage criteria for levees, with a focus on incorporating new seepage analysis procedures besides Blanket Theory. Finite element analysis is one such method that has more recently become the method of choice for general seepage analyses in geotechnical engineering. The focus of this research is mainly on underseepage analyses of levees in the lower Mississippi valley using numerical modeling, with a goal of helping engineers in making the transition from current Corps methods to finite element analysis. General guidelines are provided to conduct seepage analysis using finite element analysis for pre-defined Blanket Theory cases as well as for the design of seepage berms. In addition, the 3D finite element modeling is conducted for a full-scale field load test involving complex geometry and stratigraphy, which is useful in better understanding the response of levees and I-walls. / Ph. D.

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