240 research outputs found
A Model Compound Study in Syngas Tar Reforming
Biomass or coal gasification are promising processes for renewable energy. However, a major operating problem in gasification is what to do with syngas byproducts such as H2S and tars (heavy hydrocarbons) that cause catalyst deactivation downstream. Studies have shown that rare earth oxides (REOs) doped with transition metals are promising catalysts for tar reforming in the presence of sulfur.(R. Li, Roy, Bridges, & Dooley, 2014) In Chapter 1, propane is studied as a model compound for tar reforming with transition metal-doped (e.g., Mn, Fe) REOs. These are compared to a typical commercial Ni/Al2O3 catalyst. The results showed that REO/TM catalysts have higher reforming activity over the temperature range 920-1000 K, with no significant deactivation in non-sulfur containing feeds. In particular, Mn/Ce4, Mn1.1/Ce3/La and La/Ce3 (the numbers are elemental ratios) showed good reforming activity with relatively low carbon, CO2 and CH4 yields. Mn/Ce4 showed some, but not complete, deactivation when tested with an H2S-containing feed. All used catalysts were subjected to TPO analysis and H2 chemisorption. No correlation could be found between either reforming activity or carbon yield (as calculated from the mass balances), or the TPO or dispersion (chemisorption) results, although the dispersions did show that the transition metals remained doped in the REOs. Kinetics calculations showed that most of the catalysts have near zero-order kinetics with respect to water. In Chapter 2, educational modules related to biomass unit operations are presented, as part of the Energy Sustainability Remote Laboratory (ESRL) project. The modules relate to a biological pH-swing crystallization and a sugar-milling process. Brief introductions to the fundamental theories of both unit operations are provided to aid students’ understanding of them. Laboratory assignments and exercises are designed to focus on enhancing students’ experiences in typical operating problems, such as analyzing and finding discrepancies in experimental data, building mass balances around units, and analyzing relevant probability distributions related to the data. Students can utilize mathematical software such as Excel’s Solver and Matlab to complete certain assignments. Written solutions, Excel spreadsheets and Matlab codes for laboratory assignments and exercises are provided in Appendix C
Evaluation of Selected Nuproxa Feed Additives for protection against lameness and improving the wellbeing of broilers in a lameness challenge model
A common concern in commercial industries profiting from broiler chickens is their inability to yield a completely healthy flock. Bacterial Chondronecrosis with Osteomyelitis poses a threat to these companies by impairing the birds\u27 proximal and distal tibial and femoral heads. In 2000, roughly 17.3% of broiler chickens were affected by Bacterial Chondronecrosis with Osteomyelitis which caused a substantial economic loss in the industry (McNammee et al., 2000). BCO cannot be tied to a particular bacterial species; this experiment focuses on evaluating the efficacy of certain commercial feed additives while determining the bacterial species causing BCO in this set of the flock by process of induction of the disease, manipulation, and maintenance of flock lifestyle, and eventual necropsy of the chickens. The farm setup where this experiment was conducted consisted of 26 pens and 1560 male chicks. Of the 26 pens, 2 of the pens were wire floored to create physical stress on the lower extremities, while the other 24 pens were litter floored. The pens were arranged in two rows of 13 and were 5*10 feet squared. The initial two pens of each row, pens 1 and 14, were the wire floored pens. Each pen began with 60 chicks and was eventually culled down to 50 chicks per pen on day 14. The pens received standard feed starter in crumbles from days 1-34 and then were switched to a finisher given through pellets from days 35-56. The six different treatment groups were distributed over the 26 pens and consisted of varying amounts of Nuproxa feed additives. Pens 1 and 14 were designated under treatment one and were the pens used to induce lameness through wire flooring and a standard diet without additives. A further detailed description of the treatments can be found in Table 1. Beginning on day 22, the birds were weighed and diagnosed as lameness began to appear. On day 56, the remaining birds underwent an extensive necropsy on the last day of the trial. They were weighed, their tibia and femurs were evaluated, samples of their lesions on their tibia and femur were taken, and Inflammasome and FITC-D analysis was completed
Equivalence: A Covariantly Constant Problem in General Relativity
In studying the space-time structures described by Einstein’s theory of general relativity, it is often useful to identify particular properties referred to as geometrical invariants. These are attributes of the space-times which do not change regardless of the underlying coordinate systems used to study them. This project is part of a larger effort to catalogue space-times studied in general relativity. Specifically, computational software was used to identify structures known as covariantly constant vector fields
Targeted short-term nutrient reduction to manage Ventenata dubia an invasive winter annual grass: soil and plant responses
Invasive winter annual grasses, IWAGs, have degraded extensive ecosystems around the world and continue to invade new ones yearly. IWAGs readily form large monocultures or near monocultures, thus management and restoration goals largely focus on maintaining or increasing plant diversity in impacted ecosystems. Unfortunately, common management methods also reduce native plant diversity and harm the soil microbiome. These effects require additional measures to be taken, like reseeding, and plant diversity is still usually well below remnant targets. Early season short-term nutrient reduction to manage IWAGs is largely unexplored and would potentially decrease IWAG abundance, active earlier than most plants, but impact later season species less. Low rates of labile carbon, as sucrose, were applied to soils in a Pacific Northwest semi-arid grassland in early spring to stimulate microbial growth and temporarily reduce nutrient availability to the IWAG Ventenata dubia. Inorganic nitrogen was tracked throughout the experiment and plant and soil microbial community changes were determined at the end of the growing season. Labile carbon application reduced nitrogen at the beginning of the year, but effects did not persist to mid may when most plants were still active and soil moisture was not limiting. Treatments reduced V.dubia cover, per area seed production, and seed mass with no corresponding impact on perennial or other annual plants, except at the highest application rate when annual cover was reduced by 2%. The soil microbial community, determined via PLFA and NLFA analysis, was largely unchanged at the end of the season with slightly higher bacterial biomass and, importantly, no reduction in AMF abundance. These results suggest that this method has few negative impacts on the plant and soil community aside from a reduction in V.dubia cover and possibly its seed bank. This short-term nutrient reduction method has the potential to not only target IWAGs, active early, but also any non-native plants targeted for management that are active earlier or later than the native plant community
Stepwise stress testing of different CAD/CAM lithium disilicate veneer application methods to lithium disilicate substructure
Indiana University-Purdue University Indianapolis (IUPUI)Objective: CAD/CAM technology allows fabrication of thin lithium disilicate (LD) veneers to a LD crown substructure in place of using traditional feldspathic porcelain (FP) which has inferior mechanical properties. This project investigated the effect of different LD veneer applications to LD substructure on the biaxial flexural fatigue of LD veneer/substructure restorations.
Materials/Methods: Forty-five LD discs (Ø = 120.7 mm) were fabricated that, when combined with the veneering discs, achieve final dimensions of (Ø = 121.2mm). Experimental groups were (n = 15) as follows: (1) Resin Bonded LD Veneer (RBLDV), LD veneer (Ø = 120.5 mm) adhesively cemented to LD (0.7 mm); (2) Sintered LD Veneer (SLDV), LD veneer (Ø=120.5 mm) sintered to LD (0.7 mm); (3) Sintered Feldspathic Veneer (SFV), feldspathic porcelain (FP) applied to LD discs to achieve a final dimension of (Ø = 121.2 mm). A fourth group of (1.2 mm) monolithic LD served as the control. Weibull-distribution survival analysis was used to compare the differences of the resistance to fracture after fatigue between groups. Total number of cycles were analyzed using one-way Anova (p < 0.05).
Hypothesis: Adhering or sintering a thin laminate layer of LD on another LD surface would result in increased fracture resistance in comparison to sintered FP on LD.
Results: The SFV group had significantly lower fatigue resistance than SLDV and RBLDV groups (p < 0.05). The RBLDV group fractures resulted in significantly more fractured fragments in comparison to the other groups. No statistical difference was observed in the number of cycles. The results also showed that the LD veneered groups presented similar resistance to fatigue as monolithic discs of the same overall dimensions.
Conclusion: The hypothesis was accepted suggesting that veneering a LD substructure with a LD veneer, bonded or sintered, has increased resistance to fatigue as FP veneering material on a LD substructure. In addition, it was observed to have similar resistance to fatigue in comparison to the monolithic LD group
Which GABA Receptors Are Expressed in the Zebrafish Lateral Line?
The presence of the neurotransmitter GABA in the mammalian inner ear is well established, yet its role in regulating inner ear cell function is less clear. We seek to understand the role of the GABA in the inner ear using the model organism zebrafish. Zebrafish possess a sense that humans do not: they can detect water movement with their lateral line system. Zebrafish sense water movement with cells that project out from the body of the fish into the environment. These so-called hair cells are remarkably similar to the sensory cells of the cochlea and semi-circular canals. Because they are on the outside of the zebrafish, and not behind a bony skull, lateral line hair cells are easily accessible to study. Therefore, we are determining if we can use the lateral line system to understand more about GABA in the inner ear. We have used RNA extraction and RT-PCR to detect the expression of 27 GABA-related genes in zebrafish. We have also identified a novel alternative exon in one isoform. Overall, our results suggest that the genes expressed in the lateral line are orthologs of genes expressed in the mammalian inner ear, and thus zebrafish appear to be an appropriate model organism with which to further study GABA function in the inner ear
Clasificación de los frutos por madurez mediante impactos no destructivos.
Algunos factores de calidad, tales como el tamaño, la forma, el color, el sabor la firmeza y el aroma están muy relacionados con el estado de madurez de los frutos. Se han estudiado diversos parámetros fÃsicos para determinar su relación con la madurez de los frutos por ensayos no-destructivos. Estudio anteriores indican que un grupo de parámetros de impacto pueden ser utilizados para predecirla. Este trabajo se ha llevado a cabo con dos variedades de pera ("Blanquilla" y "Decana de Cornice") y con dos de manzana ("Golden Delicious" y "Starking"). Durante varias semanas (campaña 1990, 1991) se ensayaron muestras de frutos de distinta madurez. Los ensayos de impacto se han completado con una serie de ensayos paralelos destructivos para realizar un seguimiento de la madurez hasta senescencia. Con los datos de 11 parámetros de impacto relacionados con la madurez, se ha realizado un análisis discriminante paso a paso. AsÃ, hemos podido conocer las variables que más discriminan, en cuanto a madurez, a lo largo del tiempo. Con estas variables y los datos obtenidos en los ensayos, se ha creado un procedimiento informatizado y una base de datos, los cuales permiten la clasificación automática de frutos por medio de impactos mecánicos no destructivos. El correspondiente dispositivo se encuentra en fase avanzada de diseño y pendiente de patente
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