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A specific gravity study of some of the Southeast Missouri lead ores and tailingsO'Meara, Robert Gibson. January 1926 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1926. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 20, 2009) Includes bibliographical references (p. 80).
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Novel Spectral and Biochemical Indices for Profiling Animal Stress and Reproductive StatesCounsell, Kristen Rae 04 May 2018 (has links)
Biological samples (e.g. blood, urine) contain significant amounts of information with regard to physiological states, such as stress and reproduction. The detection and diagnosis of these states often require hormone analysis or specific instrumentation. From a holistic perspective, near infrared (NIR) spectroscopy is used to detect and differentiate physiological states using spectral indices. In a quantitative context, three techniques were compared for their ability to provide accurate and reliable biochemical indices to determine urinary hormone concentrations. The objectives in this study were (1) to map NIR profiles of reproductive metabolites in water, (2) to differentiate estrous, pregnancy, and parturition using NIR, (3) to evaluate urinary normalization methods across stress and reproductive profiles, and (4) to validate an assay for the quantification of stress levels in urine and skin swabs. To investigate these objectives biological samples from mares, giant pandas (Ailuropoda melanoleuca) and Colorado boreal toads (Anaxyrus boreas boreas) were analyzed.
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Relationship of some coniferous wood strength properties to specific gravity variations within growth incrementsHomoky, Stephen George John January 1966 (has links)
Tensile and compression strength properties of six coniferous woods were studied at the tissue level. Relationships of these properties to specific gravity variations in three adjacent growth increments of each species were explored. Pacific yew was excluded from tensile strength analyses, since the material available did not lend itself to micro-tensile testing.
The main purpose of the investigation was to examine, at the tissue level, in what manner specific gravity influences tension parallel and compression perpendicular to grain strengths. Wood strength—specific gravity relationships for gross wood based on earlier studied, were compared to tissue relationships. Distributions of specific gravity and stresses within growth increments of woods having gradual transition from earlywood to latewood, as represented by western white pine, and of woods having abrupt transition, as Douglas fir, were also compared. Feasibility of radial micro-compression test methods established previously for Douglas fir were re-examined and extended to all six species.
Experimental material, from freshly felled trees was never dried before physical testing, except western red cedar. Specimens for tensile and compression tests were cut from each increment studied. Micro-specific gravity determinations, based on green volume and oven-dry weight, were performed on broken tensile test specimens after extraction with standard solvents. Physical tests were carried out by established techniques.
Regression analysis was employed to establish equations and curves best describing relationships of maximum micro-tensile and micro-compression stresses to specific gravity. Test results revealed highly significant relationship between maximum micro-tensile stress and specific gravity, and between maximum micro-compression stress and specific gravity. The latter relationship is curvilinear, expressed by an exponential curve fitting five of the six species studied. Pacific yew, also significantly correlated to specific gravity at 95 per cent probability, was described by the same basic equation applied to the grouping of the other five woods, but with different constants.
This suggests that specific gravity influences maximum micro-compression stress variations in species of greatly different physical and anatomical, characteristics in varying degrees.
Comparing tensile and compression stress—specific gravity variations of gross wood with those of wood tissue, it was found that in both properties specific gravity caused greater stress increase of gross wood than of tissue, as illustrated by respective regression lines.
No definite trend of specific micro-compression stress within growth increments was found. Specific micro-tensile stress distributions showed a peak-value close to or at the initiation of latewood.
Specific gravity, maximum micro-tensile stress and maximum micro-compression stress in woods having gradual transition from earlywood to latewood vary gradually across the increment, suggesting trends of a second degree parabola. In woods where transition is abrupt, the increase of these properties is abrupt at or close to the initiation of latewood. If in such woods the latewood zone is wide the distribution curve is sigmoid.
Methods for testing wood tissue in radial compression, as well as theories related to the analysis of stress-deformation curves, have been verified. Ultimate load is recorded at the inflection point on the curve, beyond the proportional limit. At this phase of compression ultimate compressibility of the tracheids is achieved. / Forestry, Faculty of / Graduate
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Growth as related to specific gravity and size of seedRenich, Mary Emma, January 1900 (has links)
Thesis (Ph. D.)--University of Illinois, 1920. / Vita. "Reprinted from Transactions of the Illinois State Academy of Science, vol. 14, 1921." "The common garden bean ... was chosen for these experiments." p. 4. Bibliography: p. 24.
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Inheritance of potato chip color and its association with specific gravityCunningham, Charles Everett, January 1962 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Zur geschichte des spezifischen gewichtes im altertum und mittelalterBauerreiss, Heinrich. January 1914 (has links)
Inaug.-diss. -- Erlangen. / Includes bibliographical references.
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Nitrogen Uptake Effects on Potato Yield and QualityAyyildiz, Enise January 2021 (has links)
Nitrogen (N) is one of the vital elements for potato production. As well as common synthetic fertilizers, turkey manure compost (TMC) is more commonly used as a source of N for potato production in Minnesota. The aim of this study was to compare traditional N sources and applications (urea broadcast, Environmentally Smart Nitrogen (ESN) broadcast, and ESN banded at hilling) to TMC broadcast prior to planting on yield and quality of Russet Burbank in Minnesota. The TMC treatment resulted in a similar marketable yield compared to the urea and ESN treatments. The TMC also increased the percentage of the >170 g tuber yield. French fry color quality was not affected by N treatment in either year. The TMC was a good nitrogen source that is readily available and provides a good sustainable option for potato production. Further work should examine what benefits conventional fertilizer can have when used with TMC.
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A densidade aparente como estimador de propriedades de resistência e rigidez da madeira / Correlations between the specific gravity, physical and mechanical properties of wood from forty brazilian native species of hardwoodsDias, Fabricio Moura 11 October 2000 (has links)
A madeira tem aplicações já difundidas em diversos setores, no entanto, muitas vezes é utilizada sem o conhecimento de suas propriedades. A caracterização de espécies de madeira consiste em determinar suas propriedades físicas, de resistência e rigidez através de ensaios normalizados. O inconveniente de grande parte desses ensaios é a utilização de equipamentos de alto custo e grande porte, disponíveis apenas em centros de pesquisa. Porém, o ensaio de densidade aparente é de fácil determinação por utilizar equipamentos simples na sua execução. Sendo assim, neste trabalho são determinadas as correlações entre a densidade aparente e as propriedades físicas, de resistência e de rigidez da madeira, de quarenta espécies nativas brasileiras, do grupo dicotiledôneas. Através de análise estatística, foram obtidas expressões matemáticas que permitem estimar, a partir da densidade aparente, grande parte das propriedades de resistência e rigidez da madeira. Tais expressões são apresentadas como proposta para a utilização na caracterização de espécies menos conhecidas, o que viabiliza o adequado emprego de espécies nativas nas mais variadas aplicações para as quais a madeira é indicada. Apresentam-se também aferições das expressões propostas pela norma brasileira NBR 7190, que permitem a caracterização simplificada das resistências da madeira de espécies usuais a partir dos ensaios de resistência à compressão paralela às fibras. / Wood has diffused applications in several sections, however, a lot of times it is used without the knowledge of its properties. The characterization of wood species consists of determining its physical, strength and stiffness properties, through normalized tests. The inconvenience of many of those tests is the use of equipments of high cost and great load, available just in research centers. Even so, the test of specific gravity is of easy determination for using simple equipments in its execution. Being like this, in this study the correlations between the specific gravity, physical and mechanical properties of wood from forty brazilian native species of hardwoods are determined. The mathematical expressions obtained through this study, permit estimate most wood properties of strength and stiffness, based on their specific gravity. Such expressions are proposed as means of characterizing less-known species, what makes possible the appropriate employment of native species in most varied applications for which wood is the indicated material. Furthermore, it is presented the calibration of the expressions proposed by the brazilian code NBR 7190, being these a simplified method of characterizing mechanical properties of common species of wood by means of tests of strength in compression parallel to the grain.
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A importância da arquitetura hidráulica para a compreensão do padrão de distribuição de árvores em uma floresta de terra firme na Amazônia CentralCosme, Luiza Helena Menezes 31 May 2016 (has links)
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Previous issue date: 2016-05-31 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Environmental filters act directly on the distribution and composition of species. However, it
is not known how soil and belowground hydric conditions are related to hydraulic
characteristics of the xylem, branches and of the whole plant on a local scale. We examined
wood density and anatomy, height, leaf area, specific leaf area, and the leaf area:sapwood area
ratio at the branch level in valleys and plateaus of the terra-firme forest in Central Amazonia.
These environments present contrasting table water depths and soil textures. We measure 20
traits related to branches, stem, and whole plant in 28 congeneric species pairs from 12
genera, each containing one valley and one plateau species. Species associated with the
plateaus or valleys showed trait differences that indicate distinct investments in prevention
against hydraulic failure and driving efficiency, respectively. On plateaus, species had higher
wood density, lower averages of vessel size and hydraulic diameter of the vessel, smaller stem
sapwood area and smaller specific leaf area. Some correlations between traits change
according to the contrasting environmental conditions, demonstrating that species have
different investments in traits according to the water conditions in the soil. The maximum
adult stature in contrast environments was associated with different investing in conductivity
efficiency through the xylem anatomy.We conclude that even in a fine scale, with few meters
separating contrasting soil texture and water table depth conditions, environmental filters may
impose ecological restrictions on trees that could explain species complementary distribution
in Central Amazonia. These filter may be stronger in phylogenetically closely related species,
which show more similarities and compete for the same resources. Thus, contrasting soil
texture and water table depth conditions may be important determinants of species
composition and diversity . Thus, we suggest that hydraulic attributes and their relationships
with the environment must be better understood, especially on a local level. / Filtros ambientais atuam diretamente sobre a distribuição e composição de espécies. No
entanto, não se sabe como solo e as condições hídricas abaixo do solo estão relacionados às
características hidráulicas do xilema. Nós examinamos a densidade da madeira e anatomia da
madeira, altura, área foliar, área foliar específica e a razão entre área foliar:área de xilema
ativo no nível do ramo em espécies de árvore que ocorrem no baixio e platôs em uma floresta
de terra-firme. Esses ambientes apresentam diferenças na profundidade do lençol freático e
textura do solo. Nós medimos 20 traços funcionais em 28 pares de espécies congenéricas de
12 gêneros. Cada par com uma espécie associada a baixio e uma espécie associada platô.
Espécies associadas aos platô ou baixios mostraram diferenças que indicam investimentos
distintos na prevenção contra a falha hidráulica e eficiência de condução, respectivamente.
Em platôs, as espécies apresentaram maior densidade da madeira, as médias mais baixas de
diâmetro do vaso e diâmetro hidráulico do vaso, menor área de xilema ativo no caule e menor
área foliar específica. A relação entre alguns atributos se alterou nas condições ambientais
contrastantes, e espécies de diferentes alturas nos diferentes ambientes parecem investir em
eficiencia e segurança hidráulica de maneiras distintas. Concluímos que mesmo em uma
escala fina, com poucos metros separando ambientes com condições contrastantes de textura
do solo e profundidade do lençol freático, filtros ambientais podem impor restrições
ecológicas em árvores que poderiam explicar espécies de distribuição complementar na
Amazônia Central. Estas restrições podem ser mais fortes em espécies filogeneticamente
relacionadas, que mostram mais semelhanças e competem pelos mesmos recursos. Sugerimos
que os atributos hidráulicos e suas relações com o meio ambiente devem ser melhor
compreendidos, especialmente a nível local.
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Reportando propriedades da madeira ao teor de umidade de referênciaSoares, Rainy da Conceição 09 May 2014 (has links)
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Previous issue date: 2014-05-09 / CNPq / Há muito tempo sabe-se que a resistência da madeira varia com seu teor de umidade. Com o aumento do teor de umidade da madeira observa-se uma diminuição em sua resistência mecânica, esta variação na resistência é mais sensível para baixos teores de umidade, e é praticamente desprezível para elevados teores de umidade. Decorre deste fato, que para comparar a resistência de duas espécies, ou peças, a uma determinada solicitação, é necessário estabelecer-se um teor de umidade de referência, pois uma espécie de menor resistência, com baixo teor de umidade, pode aparentar maior resistência que uma espécie sabidamente mais resistente, porém com elevado teor de umidade. A atual norma brasileira para o projeto de estruturas de madeira adota, para referência, o teor de umidade de 12%, para o qual devem ser reportados todos os resultados de ensaios. A hipótese deste trabalho é a de que reportar resultados de ensaios feitos em madeira verde, ao teor de umidade de referência, pode produzir erros bem superior a 10%, portanto, inaceitáveis ao calculo de estruturas de madeira. O procedimento adequado seria fazer uma secagem inicial, em clima padrão (Temperatura de 202oC e umidade relativa de 655%), até estabilização da massa, ou seja, até atingir a umidade de equilíbrio com o ambiente, antes de fazer os ensaios. O objetivo deste trabalho foi mostrar que os resultados de ensaios realizados com madeira muito úmida, ou seja, com teor de umidade acima do limite de saturação das fibras, não podem ser adequadamente corrigidos para o teor de umidade de referencia de 12%, pois o erro cometido nessa correção pode superar 10%. Para isto, foram comparados resultados, corrigidos ao teor de umidade de referência, de ensaios realizados em madeira seca ao ar e condicionada (valores já próximos a 12% de umidade) com os obtidos em madeira muito úmida, no caso saturada em água. Para dar consistência estatística foram utilizadas 10 espécies diferentes de madeira. De cada espécie foram realizados ensaios de compressão paralela (resistência e rigidez), cisalhamento e densidade aparente, nas três condições de umidade já definidas. Utilizando-se como variável o “erro relativo”, tomando por base o valor corrigido, por expressões já validadas na literatura para o intervalo de umidade entre 10 e 20%, a partir da situação “madeira condicionada”, foi aplicado o teste de Tukey, cujos resultados indicam que as correções feitas a partir das situações “madeira condicionada” e “madeira seca ao ar” são estatisticamente equivalentes e diferem das correções feitas a partir da situação “madeira saturada”. Conclui-se, dessa forma, que para reportar valores à umidade de referência não se pode partir de ensaios em madeira com elevado teor de umidade, os corpos-de-prova devem estar condicionados ou secos ao ar. / For a long time it is known that the wood strength varies with its moisture content. Increasing wood moisture content occurs a decrease in its mechanical strength, this variation in resistance is more sensitive to low levels of moisture content, and is practically negligible to high levels of moisture content. Happens from this fact, that to compare two species strength, or wooden pieces, to a specific request, it is necessary to establish a reference moisture content, because a lower strength species, with low moisture content, can to present higher strength that a greatest strength species, but with higher moisture content. The current Brazilian Code for the timber structures design adopts for reference, the 12% moisture content, to which all tests results must be reported. The hypothesis of this work is that when reporting results of tests made in wood green, to the 12% moisture content, the errors can be superior to 10%, therefore, unacceptable to timber structures design. The proper procedure would be to make an initial drying, on standard weather, until mass stabilization, that is, until it reaches the moisture content equilibrium with the environment, before making the tests. The objective of this work was to show that the results of tests conducted with very wet wood, i.e. with moisture content above the fibers saturation limit, cannot be adequately corrected for the 12% reference moisture content, because the error committed in this correction can overcome 10%. To this, results of tests conducted in air-dried wood and conditioned (values already close to 12% moisture content) were compared with those obtained in very wet wood, in this case wood saturated in water. These results were previously reported at reference moisture content. For statistical consistency were used 10 different species of wood. Of each species were conducted tests of compression parallel to the fibers (strength and stiffness), shear strength and specific gravity, on the three defined conditions for moisture. Using as variable the “relative error”, on the basis of the corrected value by expressions, already validated in the literature for the moisture interval between 10 and 20%, from the situation “conditioned wood”, Tukey test was applied and the results indicate that the corrections made from the situations "conditioned wood" and " air-dried wood" are statistically equivalents, but differ from corrections made from the situation "saturated wood". It is concluded, therefore, that to report tests results to the moisture content reference, these results can’t be obtained from tests on high moisture content wood. The specimens must be conditioned or air-dried before.
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