Yes / Resistance spot welding of aluminum (Al5754) to magnesium (AZ31B) alloys results in the formation of a variety of solidification microstructures and intermetallic compounds that may affect the in-service performance of the weld. This study evaluates the relationship between the welding parameters and the properties of the weld nugget that is formed, and clarifies the morphological and microstructural evolutions within the weld regions during the low-current “small-scale” resistance spot welding of Al5754 to AZ31B. The investigations included a combination of microstructural characterization and thermodynamic analysis of the weld region. The results show that the welding time and clamping force parameters have significant effects on the properties of the nugget formed. The optimal welding parameters were found to be 300 ms welding time and 800 N clamping force. Weld nuggets formed with lower welding time and clamping force were undersized and contained extensive porosity. Meanwhile, a clamping force above 800 N caused gross deformation of the test samples and the expulsion of the molten metal during the welding process. The most significant microstructural changes occurred at the weld/base metal interfaces due to the formation of Al17Mg12 and MgAl2O4 intermetallic compounds as well as significant compositional variation across the weld pool. The thermal gradient across the weld pool facilitated the formation of several microstructural transitions between equiaxed and columnar dendrites.

Cattle consuming low-quality forage may have decreased forage organic matter intake as a result of decreased nitrogen (N) intake. To date, a value has not been assigned to dried distillers' grains as a protein supplement to cattle consuming low-quality Bermudagrass forage. To address this shortcoming in the data, 13 duodenally and ruminally fistulated steers were arranged in an incomplete 13 x 4 Latin square with 13 treatments and 4 periods. Treatments were arranged as a 4 x 3 factorial plus a negative control (NC), which received no supplement. The first factor consisted of 4 levels of supplemental protein provided at 52, 104, 156, and 208 mg N/kg BW. The second factor consisted of one of three supplemental protein sources, cottonseed meal (CSM), dried distillers' grains (DDG), and dried distillers' grains plus urea (DDGU). Total digestible organic matter (TDOMI), and total organic matter intake (TOMI) increased in response to the increasing level of supplemental protein (P <0.01). Similarly, digestible neutral detergent fiber intake (DNDFI) increased as a result of supplementation (P = 0.06). Forage organic matter intake did not increase as a result of protein supplementation (P = 0.20). However, forage organic matter intake (FOMI) responded quadratically to provision of CSM (P = 0.02). In contrast, DDG and DDGU did not significantly increase FOMI. Organic matter digestibility (OMD) tended to increase (P= 0.09) as a result of protein supplementation. Ruminal ammonia concentrations increased linearly in response to increasing provision of supplemental protein and were greater than control steers (P less than 0.01). Supplementation with DDGU resulted in the greatest increase in ruminal ammonia concentrations. Plasma urea nitrogen (PUN) concentrations increased in a linear fashion in response to CSM and DDGU supplementation (P less than 0.01), while provision of DDG resulted in a quadratic response (P = 0.08). Based on these results, DDG can be utilized as a protein supplement to increase TDOMI, however, it accomplishes this without significantly impacting FOMI which is in contrast to CSM.

5 pp. / Studies have shown the integration of whole grains into daily diet correlates with a reduced risk of many chronic diseases such as type 2 diabetes, coronary heart disease, and cancer. This article outlines the daily dietary nutritional benefits of whole grains, as well as the positive long-term health effects associated with consistent whole grain intake in diet. Also, this article provides how to find, prepare, and utilize whole grains in everyday dietary choices. Whole grain alternative cooking recipes are introduced using relatively new whole grains (quinoa, whole wheat couscous) in typical American diets.

"Tesis presentada a la H. Facultad de Agronomía de la Universidad de Concepción para optar al título de Ingeniero Agrónomo." / eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 150-154.

AN ABSTRACT OF THE THESIS OF David Williams for the Master of Ruminant Nutrition degree in Animal Science, presented on December 12, 2016 at Southern Illinois University Carbondale. TITLE: IN VITRO APPARENT RUMINAL DIGESTIBILITY OF DIETS CONTAINING CORN DISTILLERS GRAIN WITH VARYING LEVELS OF CRUDE FAT MAJOR PROFESSOR: Dr. Rebecca Atkinson
 Four dual-flow continuous fermenters were used in a Latin square design to determine the apparent ruminal digestibility and ruminal characteristics of diets containing dried distillers grains plus solubles (DDGS) at various levels of fat content. Fermenters were randomly assigned to one of the following treatments: 1) 40% DDGS containing 4.82% fat content (40 LOW); 2) 40% DDGS plus corn oil to obtain 7.5% fat (40 MED); 3) 40% DDGS plus corn oil to obtain 10.5% fat (40 HIGH); or 4) 70% DDGS plus corn oil to obtain 7.5% fat (70 MED). Rumen fluid was collected at the beginning of each period from two ruminally cannulated Angus cows previously adapted to the 40LOW treatment. Each period consisted of 10 days with a seven day adaptation period followed by three days of sample collection. Calories per gram of diet increased as percent fat increased and calories per gram was greater at the 70% inclusion of DDGS compared to 40% inclusion of DDGS at all levels of fat content. However, level of fat in the diet did not influence (P ≥ 0.35) apparent ruminal digestibility of DM, NDF, ADF, CP or total calories. Similarly, inclusion rate of DDGS had no influence (P ≥ 0.35) on nutrient digestibility. Ammonia concentrations were greatest (P = 0.0002) for 70 MED compared to the other treatments. However, treatment had no impact (P ≥ 0.16) on volatile fatty acid production with the exception of propionate which increased (P =0.05) as the level of DDGS increased from 40 to 70% inclusion rate. This data would suggest that level of fat content of DDGS has no negative influence on apparent ruminal digestibility and select ruminal characteristics. From an economic perspective, higher fat DDGS should have a higher price differential, but lower fat DDGS can still be an effective protein and energy substitute.

Evidence indicates that the sorghums were grown as cultivated crops in Egypt as early as 2200 B. C. The sorghums are native to Africa, but indications are that they may have evolved independently in India.

La nouvelle technique d'hyperdéformation nommée High Pressure Tube Twisting (HPTT), est un procédé continu d'affinement du grain pour les matériaux métalliques avec la géométrie tubulaire. Il consiste à placer un mandrin dans le tube avant d'appliquer une compression axiale directement sur le tube confiné des deux côtés pour produire une pression hydrostatique importante. Le tube est ensuite cisaillé par un couple externe à l'aide de la force de frottement généré par la pression hydrostatique. Les structures ultrafines produit avec HPTT ont été confirmés par MET et leur propriétés mécaniques ont été évaluées. La limite d'élasticité est augmentée de façon monotone avec la déformation imposée par HPTT. L'évolution de la microstructure est étudiée par la technique EBSD et les mesures de texture ont été réalisées avec des rayons X. Les échantillons déformés ont la texture de cisaillement simple, avec des intensités relativement faibles et l'effet de la texture initiale sur la texture finale persiste jusqu'à un cisaillement de 6. La distribution des désorientations entre les grains est bimodale et le second pic augmente avec la déformation. Application industrielle de cette nouvelle technique SPD exige la modélisation avancée en termes d'évolution de texture et le processus de fragmentation des grains. Dans ce but, le nouveau modèle de fragmentation du grain proposé par Toth et al. a été utilisée. L'affinement du grain améliore les résultats de simulation texture de façon significative et donne des informations complémentaires sur la distribution et la taille moyenne des grains, et la distribution de désorientation qui peut être directement comparés aux résultats expérimentaux / The new severe plastic deformation (SPD) technique, designated as high pressure tube twisting (HPTT), is a continuous process for grain refinement in bulk metallic materials with tubular geometry. It consists of placing a mandrel into the tube before applying an axial compression directly on the tube confined on both sides to produce high hydrostatic pressure. The tube is then twisted by an external torque with the help of the friction force genrated by the hydrostatic pressure. The ultra-fine grained structures produced with HPTT were confirmed using transmission electron microscopy and their microstructure and mechanical properties were evaluated. The value of yield stress is increased monotonically with the deformation imposed by HPTT. Meanwhile, the inverse deformation path is proved to be less advantageous. Microstructural evolution is studied by EBSD technique and texture measurements were carried out using X-ray. Deformed samples have simple shear texture with relatively low intensities and the effect of the initial texture on the final texture persists up to shear strain of nearly 6. Grain-to-grain misorientation distribution functions are bimodal and the second pick become higher with increasing strain. Industrial application of this new SPD technique requires advanced modelling in terms of texture evolution and grain fragmentation process. For this purpose, the new grain refinement model proposed by Toth and al. was used. Grain refinement improves the texture simulation results significantly and gives information on the average grain size, grain size distribution and misorientation distribution function that can be directly compared to experimental results

The objective of this study was to evaluate the lighter fraction of DDGS as a possible feedstuff for cattle. To accomplish this, a digestion trial was performed to determine nutrient digestibility and crude protein retention by steers consuming the lighter fraction of DDGS. Steers received L, a diet containing the lighter fraction of DDGS, D, a diet containing whole DDGS, or C, a control diet. Steers receiving L consumed less DM than steers receiving D and C. CP retention and digestibilities of DM, OM, ash, NDF, ADF, HC, and energy did not differ among steers in different treatment groups. Fat digestibility was greatest for steers consuming L and D. Steers consuming L digested more CP than steers receiving C, with steers consuming D being in between. These data suggest that the lighter fraction of DDGS can be effectively fed to cattle without adversely affecting digestibility.

Les alliages à grains ultrafins semblent prometteurs, au vu de leur forte résistance en traction et de la possibilité d'une mise en forme superplastique à basse température. Toutefois, leurs mécanismes de déformation, qui comportent une part plus ou moins forte de glissement aux joints de grains restent mal connus, et leurs performances en fatigue ont été peu étudiées. Ce travail vise à comparer et analyser le comportement viscoplastique et les mécanismes de déformation et d'endommagement en traction et en fatigue d’un alliage d’aluminium-magnésium "classique" et à grains ultrafins (600nm en moyenne) obtenu par déformation plastique sévère, selon le procédé ECAP.Des essais de relaxation, fluage et traction à diverses vitesses et températures ont permis de mesurer les évolutions des sensibilités à la vitesse en fonction de ces deux paramètres et de montrer: 1) que le raffinement microstructural accroît sensiblement la sensibilité à la vitesse 2) que ce paramètre augmente avec la vitesse de déformation 3) qu'il contrôle la ductilité du matériau à grains ultrafins, qui s'accroît donc à faible vitesse 4) que cette ductilité devient supérieure à celle du matériau classique lorsque la température s'élève. Les domaines de vitesse et température dans lesquels le raffinement microstructural accroît ou diminue la résistance en traction ont été délimités.Les mécanismes de déformation et d'endommagement des deux matériaux ont été étudiés au moyen d'essais de traction sous MEB accompagnés de mesures des champs de déformation par corrélation d'images à plusieurs échelles: méso et microscopique, grâce à des microgrilles d'or et sub-micrométrique, grâce à un mouchetis très fin obtenu par démouillage d'un film d'or. Le glissement aux joints est d'autant plus actif, dans les deux matériaux, que la température augmente et que la vitesse de déformation diminue. Dans l'alliage à grains ultrafins, il a un caractère coopératif et survient préférentiellement aux joints de forte désorientation. Les champs de déformation sont plus hétérogènes dans le matériau à grains ultrafins, où le taux de déformation dépasse 100% dans des bandes localisées.Un modèle éléments finis 2D intégrant, outre la viscoplasticité au sein des grains, un glissement visqueux des joints, a été identifié dans toute la gamme de température explorée et rend assez bien compte du comportement viscoplastique des deux matériaux et de la contribution beaucoup plus forte du glissement aux joints dans l'alliage à grains ultrafins. Il permet également de préciser comment évolue cette contribution au cours de l'écrouissage.Des essais de traction-compression à déformation plastique imposée ont permis d'étudier la plasticité cyclique et les mécanismes d'endommagement en fatigue oligocyclique et des essais à contrainte imposée, d'explorer la fatigue à grand nombre de cycles. Les essais ont été suivis d'observations des surfaces de rupture et d'une analyse statistique de l'endommagement en surface, ainsi que d'observations au MET des arrangements de dislocations. Les deux matériaux manifestent un durcissement cyclique, plus modeste dans l'alliage à grains ultrafins, qui présente, à forte amplitude, une croissance de ses grains. L'écrouissage isotrope prédomine dans l'alliage classique, où la densité de dislocations augmente fortement avec la plasticité cyclique, alors que l'écrouissage cinématique prédomine dans l'alliage à grains ultrafins, en raison de sa moindre aptitude à stocker des dislocations et de la plus grande hétérogénéité de sa déformation plastique. A même amplitude plastique, ce dernier a une durée de vie plus faible, en raison d'un amorçage bien plus rapide des fissures, à partir de particules intermétalliques. A contrainte imposée, le matériau a grain ultrafins a une durée de vie légèrement supérieure, grâce à une propagation plus lente des microfissures, dont le trajet est transgranulaire dans les plus gros grains et intergranulaire dans les plus petits. / Ultrafine grained (UFG) alloys seem promising, based on their high tensile properties and the possibility of superplastic forming at relatively low temperature. However, their deformation mechanisms are not fully understood, and their performance in fatigue has not been thoroughly investigated. This work compares the viscoplastic behavior, and the deformation and damage mechanisms in tension and fatigue of a UFG Al-Mg alloy (600 nm mean grain size) obtained by severe plastic deformation (ECAP process) with that of its coarse-grained (CG) counterpart.The strain rate sensitivity (SRS) of both materials has been measured during creep, relaxation and tensile tests run at various strain rates and temperature. Microstructural refinement is shown to increase the SRS, which rises as the strain rate decreases, and controls the ductility. The UFG material becomes softer and more ductile than the CG material at high temperature. The temperature and strain rate domain for which the UFG alloy is stronger or softer has been determined.Tensile tests run in a SEM, with DIC measurements of strain fields at meso/ micro scales (using gold microgrids printed by electron beam lithography) and at sub-micron scale (using a superfine speckle obtained by film remodelling) have shown that grain boundary sliding is more and more active in both materials as the temperature rises and as the strain rate decreases. Grain boundary sliding is cooperative and occurs mostly at high-angle grain boundaries in the UFG alloy, where the strain field is more heterogeneous, and where very high strain levels (> 100%) are often observed in localized bands.A 2D finite element model taking into account the viscoplastic behaviour inside the grains, and viscous sliding at the grain boundaries has been identified other the whole temperature range investigated. It captures well the observed behaviours and the much larger contribution of grain boundary sliding in the UFG alloy. It also provides the evolution of this contribution during strain hardening.Plastic strain-controlled push-pull tests and stress-controlled push-pull tests were run to investigate the cyclic behaviour and damage mechanisms of the two materials in low and high-cycle fatigue. The tests were followed by fractographic observations, statistical analysis of surface damage, as well as TEM observations of dislocations arrangements. Both materials exhibit cyclic hardening, although it is more modest in the UFG alloy, in which grain growth occurs at high amplitude. While isotropic hardening predominates in the CG alloy where the density of dislocation strongly increases during cyclic tests, kinematic hardening predominates in the UFG alloy, because of its limited capacity to store dislocations and its more heterogeneous plastic deformation. For a given plastic strain range, the UFG alloy has a shorter fatigue life than its CG counterpart, because of a much easier crack initiation, mostly from intermetallic particles. For a given stress range, it has a slightly higher life, due to a slower development of microcracks, which have a transgranular path in the largest grains, with some intergranular growth within the smallest grains.

Orientador: Luiz Roberto Carrocci / Banca: Inacio Bianchi / Banca: Samuel Euzedice de Lucena / Banca: Carlos Yujiro Shigue / Banca: José Rui Camargo / Resumo: Neste trabalho de pesquisa foi realizadas uma análise do comportamento de grãos de arroz submetidos à passagem de fluxos de ar com variadas condições termodinâmicas (temperatura, umidade relativa / absoluta, entalpia). Esta análise foi feita utilizando-se um recipiente com capacidade para confinar 5 litros de grãos, sendo o ar forçado a escoar pela ação da sucção de uma bomba de vácuo, promovendo assim pressões relativas menores que a atmosférica no ar de secagem, proporcionando uma migração mais facilitada das moléculas de água. Como resultado deste experimento foi obtido um consumo de energia em torno de 30 % dos sistemas convencionais de secagem à lenha com tempos de processamento de 2 horas, menores que os convencionais que consomem até 6 horas. Também foi possível determinar a distância ótima de escoamento do ar de secagem pelos grãos, em torno de 16 cm, pela análise da distribuição de pressões e temperaturas medidas através do secador protótipo . Devido ao fato do processo de secagem ser extremamente dinâmico devido as variações das características do ar ambiente (temperatura, umidade, entalpia, massa específica, etc), dos grãos provenientes do campo (arroz, feijão, milho, etc) e do combustível (lenha, casca de arroz, gás natural, etc) a ser utilizado como fonte térmica, torna-se necessária a implementação de um sistema de controle capaz de promover um gerenciamento termodinâmico do processo, ou seja, monitorar as taxas de transferência de calor e água entre os grãos e o ar de secagem em tempo real, promovendo ajustes na temperatura e intensidade do fluxo de ar de secagem, assim como a velocidade de homogeneização dos grãos dentro do leito. / Abstract: In this research work an analysis of the behavior of grains of rice of the field was accomplished submitted to the passage of flows of air with several thermodynamic conditions (temperature, relative humidity / absolute, entalpia). This analysis was made being used a recipient with capacity to confine 5 liters of grains, being the forced air to drain like this for the action of the suction of a vacuum pump, promoting smaller relative pressures than the atmospheric in the drying air, promoting a facilitated migration of the molecules of water. As a result of this experiment was obtained a consumption of energy around 30% of the conventional firewood systems with times of processing of 2 hours, smaller that the conventional ones that consume 6 hours. It was also possible to determine the larger distance of drainage of the drying air for the grains around 16 cm, through the analysis of the distribution of pressures and temperatures measured through the volume. Due to the fact of the drying process to be extremely dynamic due to the variations of the characteristics of the environmental air (temperature, humidity, entalpia, specific mass, etc), grains coming of the field (rice, bean, corn, etc) and of the fuel (firewood, peel of rice, natural gas, etc) to be used as thermal source, it becomes necessary the implementation of a control system capable of promoting an thermodynamic management of the process, in other words, to follow the rates of transfer of heat and water between the grains and the drying air in real time, promoting adjustment in the temperature and intensity of the flow of drying air, as well as the speed to homogenize the grains inside of the bed. / Doutor