No description available.

No description available.

There are currently two main types of machinery used for harvesting cotton in the United States, cotton pickers and cotton strippers with or without field cleaners. These different machine types package seed cotton with varying amounts of burrs, sticks, and leaves. Harvested cotton is placed in modules for storage prior to ginning. Recent developments in the industry include on-board module builders that package seed cotton as they harvest. This leads to three methods of storage: 1) traditional seed cotton modules, 2) half-modules, and 3) round modules utilized by harvesters with on-board module builders; all of these have different levels of packaging density. Cotton is harvested under widely varying conditions throughout the country and the moisture content of seed cotton at the point of containerization can be an important factor in the final quality of the crop. Seed cotton is being stored for increasing periods of time before being processed by cotton gins. The number of cotton gins in the U.S. has decreased while the production of cotton has increased. All cotton is harvested as it matures and the harvesting rate greatly exceeds the ginning rate. As a consequence of fewer gins, increased harvesting rates and increased quantities of cotton, the storage time of seed cotton prior to ginning has increased. It is hypothesized that the impact of varying densities, varying trash contents, and increased storage times prior to ginning is impacting the quality of the cotton lint and seed. The goal of this research is to quantify the impacts of these factors. The purpose of this research is to evaluate the effects of packaging seed cotton from any of the three different harvesting methods into varying types of storage as a function of differing moisture content and increased storage time. Results are indicated in terms of quality of both the fiber and the seed of ginned samples, as well as how the quality changes affect the value of the processed cotton. Samples of seed cotton are sealed in plastic containers for up to three months at varying levels of moisture, density, and trash content. Temperature and oxygen levels are monitored during storage. Samples are ginned and cottonseed and fiber are analyzed. The results of this research indicate that density does not affect the final quality of the lint and seed harvested. Increased moisture contents have a negative effect on both the quality and the value of the seed cotton, and this effect becomes more pronounced as the length of storage increases.

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When in commercial practice seed peas (Pisum sativum) are harvested, the vines are cut and windrowed or bunched and allowed to cure for a week or longer, depending upon the moisture content of the crop and weather conditions. The sooner the crop can be threshed, the less is the chance of loss caused by rain and the often-necessary attendant operation of turning the windrow or bunch to facilitate drying. In general, growers wait until the vines, pods, and seeds are quite dry. To what extent this is necessary is not known.

The use of bioenergy has been increasing due to efforts in fossil fuels replacement. Modern bioenergy technologies aim for high efficiency and low pollution levels, which increases the need for methods for the on-line characterization of biofuels. Dielectric methods have been identified as useful for the sensing of solid biofuels because they allow for rapid, nonhazardous, nondestructive, and bulk determination of material properties. The dielectric properties describe the interaction between the material and the electromagnetic waves. Dielectric properties are intrinsic of the materials and can therefore be used for the development of prediction models that can be applied regardless of the measurement technique. The study of the dielectric properties is also important as it improves the understanding of the dielectric behavior of the materials. This thesis focuses on the dielectric properties of solid biofuels and their use in the characterization of these materials. The work presented includes the development of new methods permitting the determination of the dielectric properties of solid biofuels with large particle size (waveguide method), broadband measurement of the dielectric properties (coaxial-line probe), and the use of a previously developed method for the accurate determination of the dielectric properties (free-space method). The results includes the dielectric properties of solid biofuels and their dependence on parameters such as frequency, moisture, density, and temperature. This thesis also presents semi-theoretical models for the determination of moisture content, which obtained a RMSEP of 4% for moisture contents between 34 and 67%, and an empirical model that resulted in a RMSEC of 0.3% for moisture contents between 4 and 13%. Finally, this thesis includes measurements of the influence of salt content on the dielectric properties and a discussion of its use for estimation of the ash content of solid biofuels. 

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To improve the MixAlco process and biomass pretreatment, five studies were conducted. Three studies related to fermentation, whereas the other two investigated the effectiveness of shock tube pretreatment (STP) coupled with oxidative lime pretreatment (OLP). In the first study, the constant-selectivity assumption used in the continuum particle distribution model (CPDM) was determined to be invalid. During a 32-day batch fermentation, selectivity increased from 0.10 to 0.40 g acid/g non-acid volatile solid (NAVS) digested. Future revisions to CPDM should incorporate a non-constant selectivity term. In the second study, a revised procedure was developed to provide a more accurate determination of moisture content. Conventional drying at 105 degrees C allowed product acids to vaporize with water, which introduced errors. Using the revised procedure, calcium hydroxide or sodium hydroxide was added to samples at a concentration of 0.01 g base/g sample, which retained acids in the sample. The mass of additional retained material closely matched that of the additional retained acid. Three related studies involving biomass pretreatment were performed. In the first, recommended parameters for pretreating sugarcane bagasse with OLP and STP were determined. Recommended OLP parameters were 130 degrees C, 6.9-bar O2, and 2-h duration. The effects of solids concentration, liquid fill volume, particle size, type of shotgun shell, number of shocks, and pretreatment order were investigated. Liquid fill volume, particle size, type of shotgun shell, and pretreatment order were significant variables, whereas solids concentration and number of shocks were not. Recommended OLP parameters were used as a basis for an additional experiment. To simulate industrial-scale pile fermentation, fixed-bed batch fermentation of OLP + STP sugarcane bagasse was performed in 1-L PVC fermentors. Rubber mulch was used as a structural support material to prevent filter plugging, which had been reported in previous work. After 42 d, acid concentration reached 8 g/L with yield approximately 0.1 g acid/g NAVS fed. Poor fermentation performance was caused by short solid-liquid contact time and poor pH control. A third biomass pretreatment experiment investigated the potential of pretreated corn stover as a potential ruminant feed. Five samples (raw, OLP, STP, OLP + STP, and STP + OLP) were analyzed for composition and in vitro digestibility. STP followed by OLP increased neutral detergent fiber (NDF) digestibility from 49.3 to 79.0 g NDF digested/100 g NDF fed. On an organic matter basis, STP + OLP corn stover plus water-soluble extractives had a total digestible nutrients (TDN) of 74.9, nearly reaching corn grain at 88.1.

A norma brasileira para o projeto de estruturas de madeira foi alterada, recentemente, abandonando o método determinista das Tensões Admissíveis e adotando o método probabilista dos Estados Limites. Seguindo tendência mundial, a atual norma brasileira, estabelece um teor de umidade de referência de 12%, no qual devem ser reportados os resultados dos ensaios. Dificilmente se conseguirá condicionar, a madeira para o ensaio, com um teor de umidade de exatamente 12%, portanto, será necessário corrigir os resultados do ensaio para este teor de umidade. A atual norma brasileira propõe expressões, para fazer esta correção nas propriedades de resistência e de rigidez da madeira, baseando-se em poucos resultados de ensaios. O objetivo deste trabalho é aferir as expressões propostas pela norma brasileira, sugerindo as alterações necessárias. Uma proposta para a correção da densidade aparente, não prevista na norma brasileira, também será estudada. Para garantir uma base experimental adequada, estuda-se a influência do teor de umidade sobre as propriedades de resistência à compressão paralela às fibras, tração paralela às fibras, cisalhamento paralelo às fibras (no plano radial-longitudinal), bem como sobre o módulo de elasticidade longitudinal e a densidade aparente, em sete diferentes espécies de madeira, correspondentes às sete classes de resistência adotadas pela atual norma brasileira. Conclui-se o trabalho apresentando uma proposta para correção das propriedades de resistência e rigidez ao teor de umidade de 12%. Apresenta-se também uma proposta para a correção da densidade aparente. / The Brazilian Code, NBR 7190/97 - Design of timber structures, was revisited, recently, abandoning the Allowable Stress Method and adopting the States Limits Design Method. Following world tendency, the current Brazilian Code, establishes a reference moisture content of 12%, in which the test\'s results should be registered. It is not possible to keep the specimen, for testing, with exactly 12% moisture content, therefore, it will be necessary to correct the results for this moisture content level. The current Brazilian Code proposes expressions, to do this correction in the strength and stiffness properties of wood, based on few test\'s results. The objective of this work is to judge the expressions proposed by the Brazilian Code, proposing the necessary alterations. A proposal for the correction of the specific gravity, not presented in the Brazilian Code, it will also be studied. To this purpose, the influence of moisture content on the strength in compression and tension parallel to grain, shear parallel to grain (in the radial-longitudinal plane), as well as on the stiffness (modulus of elasticity) and specific gravity, in seven different wood species, corresponding to the seven Brazilian Code strength classes were studied. The conclusions presents a proposal for correction of the strength, stiffness properties and specific gravity, to the 12% moisture content level.