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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.
11

Practical approaches to improve the value of the Falkland Islands' sheep and wool industry

Miller, Sean Michael Unknown Date (has links)
Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.
12

Practical approaches to improve the value of the Falkland Islands' sheep and wool industry

Miller, Sean Michael Unknown Date (has links)
Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.
13

Practical approaches to improve the value of the Falkland Islands' sheep and wool industry

Miller, Sean Michael Unknown Date (has links)
Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.
14

Identifizierung und Charakterisierung natürlicher Rohstoffe als Bodenverbesserungsmittel sandiger Substrate

Garz, Kathleen 20 October 2017 (has links)
Ziel der vorliegenden Arbeit war es, natürliche Rohstoffe als potentielle Bodenverbesserungsmittel zu identifizieren und zu charakterisieren. Es sollte deren Eignung überprüft werden, ein sandiges Substrat in seinen chemischen, physikalischen und biologischen Eigenschaften messbar zu beeinflussen. Anhand von Versuchsreihen im Gewächshaus und im Freiland ist die differenzierte Wirkung der Rohstoffe auf Mais und Weizen getestet worden. Aufgrund einer Literaturrecherche wurden Rohwolle, Schafwollpellets und Biertreber betrachtet. Es zeigte sich für Biertreber, dass dieser große Mengen an Stickstoff (Nt=3,95%; C/N=12,74) bereitstellen kann. Zudem enthält er vergleichsweise viel Phosphor und Magnesium (8,68 g kg-1 und 4,05 g kg-1) aber nur geringe Mengen an Kalium (1,40 g kg-1). Weiterhin lässt sich bei Aufwandmengen von 0,5 M.-% eine kurzfristige Verbesserung der Wasserspeicherfähigkeit sandiger Substrate feststellen. Rohwolle weist im Vergleich zu Biertreber mit Nt=13,56% höhere Mengen an Stickstoff auf. Weiterhin lassen sich mit 35,41 g kg-1 höhere Mengen an Kalium aber mit nur 0,23 g kg-1 bzw. 0,34 g kg-1 geringere Mengen an Magnesium und Phosphor feststellen. Die Mineralisierung der Rohwolle erfolgt im Vergleich zu Biertreber langsam, sodass die enthaltenen Nährstoffe nur langsam pflanzenverfügbar werden. Rohwolle weist zunächst einen stark hydrophoben Charakter auf. Mit zunehmendem Abbau des Lanolins führen Aufwandmengen von 0,1 M.-% zu einer messbaren Erhöhung der Wasserspeicherfähigkeit des sandigen Substrates. Pflanzenverfügbare Nährstoffe stehen bei den industriell aufbereiteten Schafwollpellets im Vergleich zu reiner Rohwolle schneller zur Verfügung. Ähnlich wie bei der Rohwolle werden auch durch Schafwollpellets langfristig Nährstoffe freigesetzt und die Beeinflussung der bodenphysikalischen Parameter ist über längere Zeiträume nachweisbar. Allerdings müssen Aufwandmengen von 0,5 M.-% erbracht werden. / The aim of the study was to identify and characterize natural raw materials as a potential soil improver. The capacity for measurable influence on the chemical, physical and biological properties of sandy substratum was investigated. The differentiated affect of the raw materials has been tested for maize and wheat using test series in a greenhouse as well as in open fields. Raw wool, sheep wool pellets and spent grains were considered based on comprehensive literature research. It was observed that spent grains can provide large amounts of nitrogen (N=3.95\%; C/N=12.74). Moreover, it contains relatively high levels of phosphorus and magnesium (8.68 g kg-1 and 4.05 g/kg, respectively), but only small amounts of potassium (1.40 g/kg). Furthermore, a short-term improvement of the water storage capacity of sandy substratum using a application rate of 0.5 M.-\% was observed. Raw wool has higher amounts of nitrogen with Nt=13.56\% compared to spent grains. Moreover, higher levels of potassium with a value of 35.41 g/kg were observed, but spent grains have lower levels of magnesia and phosphor with values of 0.23 g/kg and 0.34 g/kg, respectively. The mineralization of the raw wool occurs slowly compared to (malt) spent grains, such that nutrients are slowly available to plants. Initially, raw wool has a highly hydrophobic character with increasing depletion of Lanolin a measurable improvement of the water storage capacity of sandy substratum using an application rate of 0.1 M.-\% was observed. Nutrients available to plants are provided quicker by industrially remanufactured sheep wool pellets in comparison to raw wool. Nutrients are released on a long-term basis by sheep wool pellets similar to the raw wool and the influence on the soil-physical properties are verifiable for longer periods of time. However, an application rate of 0.5 M.-\% is necessary.
15

Produção e caracterização da cerâmica vermelha com a adição de resíduos oriundos da lavagem da lã de ovinos

Nunes, Francine Machado 01 June 2016 (has links)
Submitted by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-03-13T18:17:27Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado_Francine Nunes_2016.pdf: 2824304 bytes, checksum: aa5a2fd56f57a8f91e1f2bcc17666fd3 (MD5) / Approved for entry into archive by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-03-13T18:18:32Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado_Francine Nunes_2016.pdf: 2824304 bytes, checksum: aa5a2fd56f57a8f91e1f2bcc17666fd3 (MD5) / Made available in DSpace on 2017-03-13T18:18:32Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado_Francine Nunes_2016.pdf: 2824304 bytes, checksum: aa5a2fd56f57a8f91e1f2bcc17666fd3 (MD5) Previous issue date: 2016-06-01 / A utilização de cinzas de resíduos sólidos para a fabricação de produtos cerâmicos tem apresentado evidências a fim de melhorar as propriedades químicas, físicas e mecânicas, minimizar os problemas ambientais e reduzir o volume de extração de matéria-prima argilosa. Em vista disso, o presente trabalho tem como objetivo avaliar a possibilidade de fabricar produtos cerâmicos a base de argila mais a adição de cinza de resíduo de lã de ovinos em diferentes percentuais, tendo por finalidade a aplicação na construção civil. O resíduo é proveniente do processo de beneficiamento da lã de ovinos em uma indústria têxtil, sendo que este foi queimado ao ar livre e peneirado em um conjunto de peneiras 20, 30, 40, 60 e 80 mesh. Foram realizadas formulações contendo apenas argila in natura e com adições de cinza de lã (CL) em percentagens de 5, 10, 20 e 30 % na massa de cerâmica vermelha, sendo submetidas à caracterização química pela Fluorescência de Raios-X (FRX) e Espectroscopia de Absorção na Região do Infravermelho com Transformada de Fourier (FT-IR); mineralógica com Difração de Raios-X (DRX); térmica pela Análise Termogravimétrica (TG) e Calorimetria Exploratória Diferencial (DSC); e física por meio da distribuição granulométrica e índices físicos. A conformação das amostras foi realizada por prensagem e extrusão à vácuo. E as contrações lineares de secagem e de sinterização, também foram avaliadas. A sinterização dos produtos cerâmicos foi realizada em temperaturas de 600, 700 e 800 °C, com taxa de aquecimento de 100 °Cmin-1 e patamar de sinterização de três horas. As propriedades estruturais dos produtos foram realizadas por meio de FT-IR e DRX, e a resistência mecânica pela tensão de ruptura à flexão. Outras análises físicas como contrações lineares de secagem, porosidade aparente, massa específica aparente e absorção de água, também foram avaliadas. Para a resistência mecânica a média dos valores obtidos variou de 0,38 ± 0,15 MPa a 6,70 ± 0,76 MPa, e para absorção de água, a média dos valores foi de 14,72 ± 0,39 % a 27,60 ± 1,05 %, para os produtos cerâmicos prensados. A avaliação destes mesmos parâmetros para os produtos cerâmicos extrudados, apresentou variação de 2,38 ± 1,47 MPa a 7,38 ± 3,00 MPa e de 8,57 ± 0,68 % a 24,80 ± 1,08 %. A resistência mecânica e absorção de água obtiveram melhores valores na temperatura de queima a 800 °C. No entanto, os valores encontrados foram abaixo do esperado devido aos produtos cerâmicos extrudados apresentar patologias como o “coração negro”. / The use of solid ash residue for the manufacture of ceramic products has been evidence to improve the chemical, physical and mechanical properties, minimizing environmental problems and reduce the volume of extraction clayey raw materials. In view of this, the present study aims to evaluate the possibility to make ceramics by the clay added by sheep wool waste ash, in different percentages. The purpose of this application is the construction bricks. The residue is derived from the beneficiation process of the sheep wool into a textile, and this was burnt at the air and sieved in a set of sieves 20, 30, 40, 60 and 80 mesh, only formulations were made containing clay and wool gray additions (CL) in percentages of 5, 10, 20 and 30 % in a red ceramic, being subjected to chemical characterization by X-Ray Fluorescence (XRF) and Fourier Transform in the Infrared Spectroscopy (FT-IR); Mineralogical with X-Ray Diffraction (XRD); Thermal by Thermogravimetric Analysis (TG) and Differential Scanning Calorimetry (DSC); through of physical and particle size distribution and physical indexes. The conformation of the samples was accomplished by pressing and vacuum extrusion. And the linear shrinkage by drying and heating, were also evaluated. The sintering of the ceramic products is performed at temperatures of 600, 700 and 800 °C with a the rate of 100 °Cmin -1 and three hours burning level. The structural properties of the products were performed by FT-IR and XRD, and the mechanical strength of the flexural breaking strain. Other physical analysis such as linear shrinkage drying, porosity, bulk density and water absorption were also evaluated. For mechanical strength average values obtained ranged from 0.38 ± 0.15 MPa to 6.70 ± 0.76 MPa and water absorption, the average value was 14.72 ± 0.39 % and 27.60 ± 1.05 % for the ceramics pressed. The evaluation of these same parameters for extruded ceramics, changed from 2.38 ± 1.47 MPa to 7.38 ± 3.00 MPa and 8.57 ± 0.68 % to 24.80 ± 1.08 %. The mechanical strength and water absorption values obtained in the best heating temperature to 800 °C. However, the values were lower than expected due to the extruded ceramic products present conditions as the “black core”.
16

Etude des transferts couplés de chaleur et de masse dans les matériaux bio-sourcés : approches numérique et expérimentale / Study of heat and mas transfer within bio-based building materials : numerical and experimental approaches

Asli, Mounir 07 December 2017 (has links)
Le travail développé dans cette thèse a pour but d’étudier le comportement hygrothermique de matériaux isolants bio-sourcés, et plus particulièrement les fibres de bois, le béton de chanvre, la laine de lin, la laine de mouton, le métisse® et les anas de lin. Ces matériaux, par essence naturels, présentent des spécificités liées à leur origine (animale ou végétale) et à leur structure (fibres, paille, matrice solide…). Leur porosité, très élevée, les rend réactifs aux variations d’humidité relative ambiante, ce qui peut impacter leurs performances thermiques et leur durabilité (comme pour tous les matériaux), mais également leur conférer des capacités de régulation. Dans un souci d’améliorer la connaissance de ces matériaux particuliers, nous proposons tout d’abord d’étudier l’impact causé par l’humidité sur leurs caractéristiques thermiques, principalement la conductivité thermique et la chaleur spécifique. Ensuite les caractéristiques hygrothermiques sont étudiées, ce qui permet de mieux comprendre les phénomènes dépendant des capacités d’adsorption, de désorption, de perméabilité ou de résistance à la vapeur d’eau. On se rend compte également de l’importance du gradient de température sur l’évolution des transferts hygriques au sein des matériaux. En plaçant les isolants bio-sourcés sous sollicitations aléatoires ou en conditions réelles d’utilisation, nous pouvons suivre leur comportement d’un point de vue expérimental. Le couplage à une approche numérique permet d’identifier les paramètres d’influence prépondérants, dans l’optique de la prédiction des transferts couplés chaleur/masse par une simulation dans des conditions particulières d’utilisation, comme la rénovation d’un habitat existant. On constate à partir de mesures in situ que ces matériaux ont une grande capacité d’adaptation à des environnements dont l’humidité relative est évolutive. / The work developed in this thesis aims to study the hygrothermal behavior of bio-sourced insulating materials, and more particularly wood fibers, hemp concrete, linen wool, sheep wool, material made of textile recycling (metisse®) and flax shives. These materials, which are essentially natural, have specific characteristics linked to their origin (animal or vegetable) and their structure (fibers, straw, solid matrix, etc.). Their very high porosity makes them reactive to the relative humidity variations, which can affect their thermal performances and their durability (as for all materials), but also give them a regulation capacities. In order to improve the knowledge of these particular materials, first, we propose to study the impact caused by moisture on their thermal characteristics, mainly thermal conductivity and specific heat. Then the hygrothermal characteristics are studied, which makes it possible to better understand the phenomena depending on the capacities of adsorption, desorption, permeability or water vapor resistance. Also, we realize the importance of the temperature gradient impact on the evolution of the hygroscopic transfers within the materials. By placing the studied bio-sourced insulation materials under random loading or under real conditions, it will be possible to follow their hygrothermal behavior from an experimental point of view. The numerical approach makes it possible to identify the preponderant influence parameters, in the context of the prediction of coupled heat and mass transfers by simulation under particular conditions of use, such as the renovation of an existing habitat. On the basis of in situ measurements, it can be seen that these materials have a high adaptability to environments whose relative humidity is evolutionary.
17

Use of bio-waste as fertiliser for the protected vegetable cultivation

Böhme, Michael Henry 22 February 2019 (has links)
The number of biogas plants in Germany is increasing from 3,711 in 2007 to 8,075 in 2016. In these biogas plants, it occurred more than 50 Mt digestate. Therefore, several investigations are started to use digestate as organic fertiliser mostly for field crop cultivation. Experiment with tomatoes was carried out were digestate was used as a supplement to the growing media in an amount of 5%, 15%, and 25%, compared with a treatment of mineral fertiliser and lupine wholemeal. The tomato yield was highest in the treatment with mineral fertilisation, the yield with 25% digestate was only a little lower. More experiments are necessary for particular regarding the amount and frequency of fertilization with digestate from biogas plants. In Germany and in Vietnam the number of sheep flocks is increasing, high amounts of uncleaned sheep wool are available. Because of the high amount of nutrients - especially nitrogen -, sheep wool pellets could be used as multi-functional fertiliser in vegetable cultivations. Four types of sheep wool pellets have been tested in protected cultivation. Tomatoes were cultivated in a greenhouse using substrate culture with perlite, bark compost, sheep wool slabs, respectively, and sheep wool pellets as fertiliser. Best growth and highest yield for tomatoes were obtained using pine bark and perlite as a substrate, both fertilised with sheep wool pellets. Based on the results of the yield and the analyses of the nutrient content in plants it seems that sheep wool pellets can be used, for the cultivation of vegetables in greenhouses. / Số lượng các nhà máy biogas tại CHLB Đức tăng từ 3.711 năm 2017 lên 8.075 năm 2016. Các nhà máy biogas sản sinh ra hơn 50 triệu tấn chất thải. Vì vậy đã có nhiều nghiên cứu liên quan đến sử dụng nguồn chất thải này làm phân bón hữu cơ cho canh tác nông nghiệp. Thí nghiệm với cà chua sử dụng chất thải biogas làm chất bổ sung dinh dưỡng cho giá thể trồng cây theo các tỷ lệ 5%, 15% và 25% đối chứng với công thức sử dụng phân hóa học và bột nguyên vỏ họ đậu. Năng suất cà chua thu được từ các công thức bổ sung chất thải biogas đều cao hơn đối chứng, chỉ có công thức bổ sung 25% có năng suất thấp hơn. Tuy nhiên vẫn cần có những nghiên cứu tiêp theo về lượng và tần xuất sử dụng bón phân với chất thải từ nhà máy biogas. Ở Đức và ở Việt Nam số lượng đàn cừu đang tăng lên, một lượng lớn lông cừu phế phẩm phát sinh. Với hàm lượng dinh dưỡng cao, đặc biệt là nitơ, viên nén từ lông cừu phế phẩm có thể sử dụng làm phân bón đa chức năng cho trồng trọt. Nghiên cứu đã sử dụng 4 loại viên nén lông cừu làm phân bón trong điều kiện trồng có kiểm soát. Cà chua được trồng trong nhà kính với 3 loại giá thể là perlite, vỏ cây thông đã ủ hoai, thảm lông cừu với phân bón là viên nén từ lông cừu phế phẩm. Năng suất cao nhất và đem lại sinh trưởng tốt nhất cho cây cà chua là công thức sử dụng vỏ cây thông và perlite. Dựa trên kết quả về năng suất và phân tích dinh dưỡng trong cây và sản phẩm, nghiên cứu cho thấy sự phù hợp của viên nén từ lông cừu phế phẩm làm phân bón cho canh tác rau trong nhà kính.

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