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- Title
- A closed-loop biorefining system to convert organic residues into fuels
- Creator
- Chen, Rui
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
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This project delivers an energy positive and water neutral, closed-loop biorefining system that converts organic wastes into renewable energy and reduces the overall impacts on the environment. The research consisted of three major stages: The first stage of this project was conducted in an anaerobic co-digestion system. Effects of the ratio of dairy manure-to-food waste as well as operating temperature were tested on the performance of the co-digestion system. Results illustrated an increase...
Show moreThis project delivers an energy positive and water neutral, closed-loop biorefining system that converts organic wastes into renewable energy and reduces the overall impacts on the environment. The research consisted of three major stages: The first stage of this project was conducted in an anaerobic co-digestion system. Effects of the ratio of dairy manure-to-food waste as well as operating temperature were tested on the performance of the co-digestion system. Results illustrated an increase in biogas productivity with the increase of supplemental food waste; fiber analysis revealed similar chemical composition (cellulose, hemicellulose and lignin) of final solid digestate regardless their different initial feedstock blends and digestion conditions. The molecular genetic analyses demonstrated that anaerobic methanogenic microorganisms were able to adjust their community assemblage to maximize biogas production and produce homogenized solid digestate. The second stage utilized electrocoagulation (EC) pretreated liquid digestate from previous stage to culture freshwater algae. Kinetics study showed a similar maximum growth rate (0.201-0.207 g TS day-1) in both 2× and 5× dilutions of EC solution; however, the algal growth was inhibited in original EC solution (1×), possibly due to the high ammonia-to-phosphate ratio. Algal community assemblage changed drastically in different dilutions of EC solution after a 9-day culture. The following semi-continuous culture in 2× and 5× EC media established steady biomass productivities and nitrogen removal rates; in addition, both conditions illustrated a phenomenon of phosphorus luxury uptake. Biomass composition analyses showed that algae cultured in medium containing higher nitrogen (2× EC medium) accumulated more protein but less carbohydrate and lipid than the 5× EC medium. The last stage involved hydrolyzing the algal biomass cultured in anaerobic digestion effluent and analyzing the effects of the neutralized algal hydrolysate on the performance of enzymatic hydrolysis of acid or alkali pretreated lignocelluosic substrates (poplar, corn stover, switchgrass, and solid fiber from anaerobic digestion). Results found that algal hydrolysate significantly improved the efficiency of enzymatic hydrolysis of lignin-rich, structurally recalcitrant biomass such as poplar and solid fiber from anaerobic digestion. This discovery broadened the potential application of algal biomass besides direct use for biofuel production.
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- Title
- Visual distraction as a means of enhancing child resistance
- Creator
- Chen, Rui
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
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Despite advances improving packaging safeguards in recent years, unintentional child poisonings remain an important public health concern. From 2001 to 2008, more than half a million children 5 or younger visited an emergency room in the U.S due to possible poisoning by medication. Data reported by the Centers for Disease Control and Prevention (CDC) in their latest report (2013) further suggests that among children, ED visits for medication poisonings are most common in children under 6...
Show moreDespite advances improving packaging safeguards in recent years, unintentional child poisonings remain an important public health concern. From 2001 to 2008, more than half a million children 5 or younger visited an emergency room in the U.S due to possible poisoning by medication. Data reported by the Centers for Disease Control and Prevention (CDC) in their latest report (2013) further suggests that among children, ED visits for medication poisonings are most common in children under 6 years of age. To limit childrens' exposure to drugs and other household items that may cause harm, the US government has required "special packaging" on specified products since the early 1970s. Our study attempts to extend early stage processing (i.e. capture a child's attention in an area of the package away from the closure system) to extend the time before opening. To do so, we applied a lenticular graphic, or a "visual distracter," to pharmaceutical vials and blisters. Distracters alternated between a frowning facial icon and the words "keep away" as the packages were moved. Two hundred and seven children between the ages of 24 and 51 months were tested in pairs. Each pair was provided one of the four treatment conditions (pharmaceutical vials with and without distracter and walleted blisters with and without distracters). Given that only 7 out of 99 subjects open the blisters successfully, no evidence for any effect of treatment on the probability of opening blisters (P=0.6522) or the time to successful opening (P=0.8196) was found. However, the results for the vials suggest the presence of a visual distracter to be a promising approach for prolonging time to opening (P=0.0375 ; Treatments that contained distracters [ME= 103.05 seconds SE 26.10]; Plain Treatment [ME=36.64 seconds SE 20.34]) and may be particularly effective in preventing younger children (24 to 40 months of age) (P=0.0356) from successfully opening vials (LSM=0.085 CI [0.0246, 0.2538]) as compared to their counterparts 42-51 months (LSM=0.2414 CI [0.0813, 0.5337] ).
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- Title
- Freshwater algal cultivation with animal waste for nutrient removal and biomass production
- Creator
- Chen, Rui
- Date
- 2010
- Collection
- Electronic Theses & Dissertations
- Description
-
Excess nutrients, particularly nitrogen and phosphorus remained in the anaerobically digested (AD) manure effluent, have major impacts on the environment if disposed inappropriately. Algal cultivation, with the advantages of faster uptake of nutrients in waste streams, year-round production, and higher photosynthetic efficiency, represents one of the best processes for the removal of excessive nutrients. Meanwhile, algae have also been proved as one of the most promising non-food-crop-based...
Show moreExcess nutrients, particularly nitrogen and phosphorus remained in the anaerobically digested (AD) manure effluent, have major impacts on the environment if disposed inappropriately. Algal cultivation, with the advantages of faster uptake of nutrients in waste streams, year-round production, and higher photosynthetic efficiency, represents one of the best processes for the removal of excessive nutrients. Meanwhile, algae have also been proved as one of the most promising non-food-crop-based feedstock for biofuels production. This study focuses on a practically and economically feasible algal cultivation system that satisfies the needs of nutrient removal, carbon sequestration, and biofuels production. Non-filamentous green algae, especiallyChlorella sp., were able to tolerate high nutrient loadings in a five-month cultivation; a chemically pretreated AD effluent which initially contained 200 mg/L of total nitrogen and 2.4 mg/L of total dissolved phosphorus (TDP) provided an optimal nutrient concentration for the cultivation of selected algae strain. Additionally, the cultivation of selected algal strain with optimal pretreated AD effluent in a pilot-scale semi-continuously fed raceway pond revealed a stable productivity of 6.83 g volatile solids (VS)/ m2 /day.
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