South Dakota State University

About: South Dakota State University is a education organization based out in Brookings, South Dakota, United States. It is known for research contribution in the topics: Population & Virus. The organization has 5700 authors who have published 10456 publications receiving 280551 citations. The organization is also known as: SDSU.

Solar Irradiance Forecasting in Remote Microgrids Using Markov Switching Model

Abstract: Photovoltaic (PV) systems integration is increasingly being used to reduce fuel consumption in diesel-based remote microgrids. However, uncertainty and low correlation of PV power availability with load reduces the benefits of PV integration. These challenges can be handled by introducing reserve. However, this leads to increased operational cost. Solar irradiance forecasting helps to reduce reserve requirement, thereby improving the utilization of PV energy. This paper presents a new solar irradiance forecasting method for remote microgrids based on the Markov switching model. This method uses locally available data to predict one-day-ahead solar irradiance for scheduling energy resources in remote microgrids. The model considers past solar irradiance data, clear sky irradiance, and Fourier basis expansions to create linear models for three regimes or states: high, medium, and low energy regimes for days corresponding to sunny, mildly cloudy, and extremely cloudy days, respectively. The case study for Brookings, SD, USA, discussed in this paper, resulted in an average mean absolute percentage error of 31.8% for five years, from 2001 to 2005, with higher errors during summer months than during winter months.

Effect of dried corn distillers grains plus solubles compared with soybean hulls, in late gestation heifer diets, on animal and reproductive performance

Abstract: Dried distillers grains plus solubles (DDGS) contain fat and rumen undegradable intake protein, both of which have been shown to increase reproductive performance in heifers. The mechanisms leading to enhanced reproduction have not been fully defined. The objectives of this research were to evaluate effects of DDGS in late gestation heifer diets on animal and reproductive performance and on blood plasma concentrations of GH, IGF-I, and NEFA. Over 2 yr, 201 heifers were randomly allotted to 1 of 2 diets, which were similar in energy and adequate in rumen degradable intake protein and were fed from d 190 of gestation through calving. Diets were grass hay with DDGS or soybean hulls (SBH) and a supplement. Cow BW and BCS were measured from the beginning of treatment through weaning. Blood samples were collected prepartum on d 71 and 69 of the feeding period and weekly after calving for 4 and 6 wk (d 84 to 105 and d 76 to 111 relative to the feeding period) during yr 1 and 2, respectively. No treatment x year interactions were detected for any of the performance, hormonal, or reproductive dependent variables. Both treatments caused positive BW changes over the feeding period, but DDGS heifers had a greater (P /= 0.26) between DDGS and SBH treatments. Treatment did not influence (P >/= 0.12) BW or BCS change during the postpartum period. Calving ease, calf vigor, and calf birth weight, weaning weight, and ADG (birth to weaning) were similar (P >/= 0.41) between treatments. The proportion of cows that had initiated estrous cycles (P = 0.46) and the pregnancy distribution (P >/= 0.21) were similar between treatments. However, a greater (P = 0.058) percentage of DDGS cows became pregnant compared with SBH cows (94 and 84%). In both years, there were no effects of treatment (P >/= 0.17) or treatment x time (P >/= 0.52), but time influenced (P 0.10) for the duration of the sampling period. Concentrations of NEFA increased from calving through d 8 and gradually declined through d 20. Prepartum diets containing DDGS, a source of fat and UIP, benefited pregnancy rates in well-maintained, primiparous beef heifers.

Expression of mucin-type glycoprotein K88 receptors strongly correlates with piglet susceptibility to K88(+) enterotoxigenic Escherichia coli, but adhesion of this bacterium to brush borders does not.

Abstract: Three antigenic variants of the K88 fimbrial adhesin exist in nature, K88ab, K88ac, and K88ad. Enterotoxigenic Escherichia coli (ETEC) strains that produce these fimbriae cause life-threatening diarrhea in some but not all young pigs. The susceptibility of pigs to these organisms has been correlated with the adherence of bacteria to isolated enterocyte brush borders. Whether that correlation holds for multiple K88 variants and over a broad genetic base of pigs is unknown and was the impetus for this study. We also desired to examine the correlation of the expression of a porcine intestinal brush border mucin-type glycoprotein (IMTGP) which binds K88ab and K88ac with the susceptibility of piglets to K88+ ETEC. Of 31 neonatal gnotobiotic pigs inoculated with K88ab+ or K88ac+ ETEC, 13 developed severe diarrhea, became dehydrated, and died or became moribund. Another pig became severely lethargic but not dehydrated. In vitro brush border adherence analysis was not possible for 10 of the severely ill pigs due to colonization by challenge strains. However, of the 17 pigs that did not become severely ill, 8 (47%) had brush borders that supported the adherence of K88ab+ and K88ac+ bacteria in vitro, suggesting a poor correlation between in vitro brush border adherence and piglet susceptibility to K88+ ETEC. By contrast, the expression of IMTGP was highly correlated with susceptibility to K88+ ETEC. Of the 12 pigs that produced IMTGP, 11 developed severe diarrhea. The other pig that produced IMTGP became lethargic but not severely diarrheic. Only 2 of 18 pigs that did not produce IMTGP became severely diarrheic. Colonizing bacteria were observed in histologic sections of intestines from all pigs that expressed IMTGP except for the one that did not develop severe diarrhea. However, colonizing bacteria were observed in histologic sections from only one pig that did not produce IMTGP. The bacterial concentration in the jejuna and ilea of pigs expressing IMTGP was significantly greater (P < 0.005) than that in pigs not expressing IMTGP. These observations suggest the IMTGP is a biologically relevant receptor for K88ab+ and K88ac+ E. coli or a correlate for expression for such a receptor.

Thermal Liquefaction of Lignin to Aromatics: Efficiency, Selectivity, and Product Analysis

Abstract: This perspective addresses efficiency and selectivity of high-temperature lignin liquefaction processes conducted in various reaction media as sub- and supercritical fluids. The challenges in efficient and selective production of high-value organic monomers from lignin are reviewed critically, along with analytical protocols essential for their accurate recovery after lignin degradation. The current approaches targeting the formation of phenolic monomers from lignin are discussed in terms of their repolymerization, a process that decreases the reaction selectivity and yield of the dominant phenolic monomers. The potential to solve this grand challenge is analyzed in terms of acid and/or protic cosolvent application, reduction of the reaction temperature, “quenching” of the reactive lignin depolymerization intermediates, and presence of heterogeneous catalysts, such as zeolites, metals, and metal oxides, sulfides, and phosphides.