Parameters influencing the evolution and oxidation of sulfur in suspension phase coal combustion

Journal ArticleStoker coal-fired boiler furnaces are significant in terms of coal consumption and environmental impact; however, they have received relatively little research attention. This paper describes the results of a two-year study on the formation of sulfur oxides in the suspension phase of a coal-fired spreader-stoker system. An eight foot, drop-tube furnace with upward hot-gas flow was used to define the evolution and oxidation of fuel sulfur in the suspension phase and to establish the influence of the combustion parameters on S02 formation. The results indicate that coal particles greater than approximately 0.1 inch fall to the stoker grate essentially unreacted. Thus, only between 8 and 20 percent of the coal feed actually burns in the suspension phase. In general, the evolution and oxidation of sulfur lags hydrogen but leads carbon. The behavior of the organic sulfur closely follows that of carbon; however, the decomposition of the sulfate sulfur depends primarily on the local temperature and oxygen concentration. The behavior of the sulfate sulfur is of major importance because of the high sulfate content of the natural coal fines

A study of changes in attitudes of fathers seen at the Children's Psychiatric Clinic of the Massachusetts Memorial Hospital.

Thesis (M.S.)--Boston Universit

Comparison of methods to estimate ruminal degradation and intestinal digestibility of protein in hydrolyzed feather meal with or without blood

Hydrolyzed feather meal (HFM) is a feedstuff high in rumen undegraded protein (RUP) that can be used as an effective source of metabolizable protein for dairy cattle. Because the production process may vary, the rumen degradability and intestinal digestibility of HFM may also vary. Additionally, some processes may incorporate additional blood into the final product to result in feather meal with poultry blood. To determine the rumen degradability and intestinal digestibility of these products, several laboratory assays can be used; the common assays are the mobile bag (MOB), modified three-step (MTS), and Ross (ROS) assays. Although all 3 assays determine RUP digestibility, they vary in whether they are performed in situ, in vitro, or both. The objective of this study was to evaluate the ruminal degradability and intestinal digestibility of HFM originating from processes that differ in their inclusion of blood, and to compare the MOB, MTS, and ROS assays. Ten samples of HFM, which were identified by the suppliers as HFM with little blood (n = 5) and with more blood (n = 5), were spot-sampled, collected from 10 production plants across the United States, and subjected to all 3 assays. Assay type had an effect on RUP, total-tract crude protein (CP) digestibility, and the amount of RUP digested. A significant effect was observed on RDP and RUP concentrations for blood inclusion; no effect was detected for total-tract CP digestibility. We found no difference in RUP digestibility for assay or blood inclusion. There was also no interaction of the effect of assay or blood inclusion. Results suggest that even though there are differences in chemical composition in HFM associated with the inclusion of blood, such as ash and crude fat, few if any differences are observed in intestinal digestion of protein. Although the assays varied in their estimates of rumen undegraded protein, MOB and MTS yielded the most similar values. However, all 3 assays resulted in similar estimates of RUP digestibility

Effect of Fat and Fiber on Methane Production and Energy Utilization in Lactating Dairy Cows

Due to rising concerns of greenhouse gases and that ruminants are the largest livestock methane producers, an emphasis has been put on developing methane mitigation strategies to reduce methane emissions in ruminants. Other than reducing methane, maximizing the energy utilization of cattle is also important for producer’s overall productivity and profitability. In the first experiment, fat or cellulose was added to fiber isolated from dried distiller’s grains and solubles. Isolated NDF residue from an in vitro setting was fermented 1) alone (control); 2) with feed grade corn oil at 20%; or 3) with cellulose powder microcrystalline at 20% using the in vitro gas production technique. Results suggested that the addition of oil or cellulose to NDF residue resulted in a decrease or no effect on methane production and total gas production, respectively. These observations further suggest that diets may be manipulated to mitigate methane from ruminant livestock. A second experiment was conducted using, eight multiparous, lactating Jersey cows in a twice replicated 4 × 4 Latin square using a headbox type indirect calorimetry to determine the effects of feeding different concentrations of fat and hemicellulose on energy utilization and methane production. For fat concentration manipulation, tallow was included at either approximately 0 or 2 % of the diet DM. For hemicellulose concentration manipulation, the inclusion rates of corn silage, alfalfa hay, and soybean hulls were changed and resulted in diets containing either 11.3 % or 12.7 % hemicellulose (DM basis). The factorial arrangement of the treatments were both high and low fat and hemicellulose (LFLH, LFHH, HFLH, and HFHH). Results suggest that methane production was not affected by treatment however methane produced per unit of DMI tended to decrease with inclusion of fat. Fiber digestibility improved with increasing concentration of hemicellulose. Methane per unit of digested NDF tended to decrease with increasing concentration of hemicellulose. Energy utilization overall was improved as net energy of lactation was improved with increasing hemicellulose in low fat diets. Advisor: Paul J. Kononof

Physical Examination of the Shoulder

https://digitalcommons.unmc.edu/emet_posters/1024/thumbnail.jp

The Prism Bridge: Maximizing Inter-Chip AXI Throughput in the High-Speed Serial Era

In this paper, we present the Prism Bridge, a soft IP core developed to bridge FPGA-MPSoC systems using high-speed serial links. Considering the current trend of ubiquitous serial transceivers with staggeringly increasing line rates, minimizing overhead and maximizing data throughput becomes paramount. Hence, our main design goal is to maximize bandwidth utilization for AXI data, which we realize through an advanced packetization mechanism. We give an overview of the Prism Bridge’s design and analyze its half-duplex bandwidth utilization. Additionally, we discuss the results of the experiments we conducted to assess its real-world performance, including measurements of throughput and latency of various combinations of line rates, link-layer cores, and bridge cores. Using a serial link with a 16.375 Gbit/s line rate, the Prism Bridge with an advanced packetizing mechanism achieved an AXI write throughput of 1368.81 MiB/s and an AXI read throughput of 1376.61 MiB/s, an increase of 46.19% and 45.85%, respectively, compared with the de-facto industry-standard core. The advanced packetization mechanism had negligible impact on latency but required 69.14%–73.91% more LUTs and 33.62%–36.19% more flip-flops. We conclude that for most designs that support inter-chip AXI transactions and will not be limited to short transaction lengths, the higher data throughput of the Prism Bridge with an advanced packetization mechanism is worth its cost in additional logic resource utilization

Variation in Modes and Rates of Evolution in Nuclear and Mitochondrial Ribosomal DNA in the Mushroom Genus Amanita (Agaricales, Basidiomycota): Phylogenetic Implications

Modes and rates of molecular evolution, and congruence and combinability for phylogenetic reconstruction, of portions of the nuclear large ribosomal subunit (nLSU-rDNA) and mitochondrial small subunit (mtSSU-rDNA) genes were investigated in the mushroom genus Amanita. The AT content was higher in the mtSSU-rDNA than in the nLSU-rDNA. A transition bias in which AT substitutions were as frequent as transitions was present in the mtSSU-rDNA but not in the nLSU-rDNA. Among-sites rate variation in nucleotide substitutions at variable sites was present in the nLSU-rDNA but not in the mtSSU-rDNA. Likelihood ratio tests indicated very different models of evolution for the two molecules. A molecular clock could be rejected for both data sets. Rates of molecular evolution in the two molecules were uncoupled: faster evolutionary rates in the mtSSU-rDNA and nLSU-rDNA were not observed for the same taxa. In separate phylogenetic analyses, the nLSU-rDNA data set had higher phylogenetic resolution. The partition homogeneity test and statistical bootstrap support for branches indicated absence of conflict in the phylogenetic signal in the two data sets; however, tree topologies produced from the separate data sets were not congruent. Heterogeneity in modes and rates of evolution in the two molecules pose difficulties for a combined analysis of the two data sets: the use of equally weighted parsimony is not fully satisfactory when rate heterogeneity is present, and it is impractical to determine a model for maximum-likelihood analysis that fits simultaneously two heterogeneous data sets. Overall topologies produced from either the separated or the combined analyses using various tree reconstruction methods were identical for nearly all statistically significant branches. © 2000 Academic Pres

The influence of fat and hemicellulose on methane production and energy utilization in lactating Jersey cattle

Feeding fat to lactating dairy cows may reduce methane production. Relative to cellulose, fermentation of hemicellulose is believed to result in less methane; however, these factors have not been studied simultaneously. Eight multiparous, lactating Jersey cows averaging (±SD) 98 ± 30.8 d in milk and body weight of 439.3 ± 56.7 kg were used in a twice-replicated 4 × 4 Latin square to determine the effects of fat and hemicellulose on energy utilization and methane production using a headbox-type indirect calorimetry method. To manipulate the concentration of fat, porcine tallow was included at either 0 or 2% of the diet dry matter. The concentration of hemicellulose was adjusted by manipulating the inclusion rate of corn silage, alfalfa hay, and soybean hulls resulting in either 11.3 or 12.7% hemicellulose (dry matter basis). The resulting factorial arrangement of treatments were low fat low hemicellulose (LFLH), low fat high hemicellulose (LFHH), high fat low hemicellulose (HFLH), and high fat high hemicellulose (HFHH). Neither fat nor hemicellulose affected dry matter intake, averaging 16.2 ± 1.18 kg/d across treatments. Likewise, treatments did not affect milk production, averaging 23.0 ± 1.72 kg/d, or energy-corrected milk, averaging 30.1 ± 2.41 kg/d. The inclusion of fat tended to reduce methane produced per kilogram of dry matter intake from 24.9 to 23.1 ± 1.59 L/kg, whereas hemicellulose had no effect. Increasing hemicellulose increased neutral detergent fiber (NDF) digestibility from 43.0 to 51.1 ± 2.35%. Similarly, increasing hemicellulose concentration increased total intake of digestible NDF from 6.62 to 8.42 ± 0.89 kg/d, whereas fat had no effect. Methane per unit of digested NDF tended to decrease from 64.8 to 49.2 ± 9.60 L/ kg with increasing hemicellulose, whereas fat had no effect. An interaction between hemicellulose and fat content on net energy balance (milk plus tissue energy) was observed. Specifically, increasing hemicellulose in low-fat diets tended to increase net energy balance, but this was not observed in high-fat diets. These results confirm that methane production may be reduced with the inclusion of fat, whereas energy utilization of lactating dairy cows is improved by increasing hemicellulose in low-fat diets