No abstract

No abstract

No abstract

Hot water pretreatment was systematically studied to determine whether reaction selectivity of cellulose toward the production of anhydrosugars and furanics could be improved. Samples of wheat straw and R-cellulose were treated using hot compressed water at temperatures ranging between 150 and 260 °C. The effect of hot water pretreatment on pyrolysis selectivity was measured using pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Various representative peak area ratios were compared and used as an index of pyrolysis selectivity. The chemical and Py-GC/MS analysis of solid residues resulting from hot water pretreatment suggest that, as the temperature increased, the hemicelluloses and amorphous cellulose were solubilized. The relative areas of the Py-GC/MS results associated with levoglucosan increased for both straw and R-cellulose with increasing treatment temperature. The results show that the selectivity of thermochemical reactions toward the production of sugars and furanics can be enhanced if the material is treated in hot water at temperatures between 220 and 260 °C, and the amount of acetic acid is reduced substantially. Thus, hot water pretreatment may be a viable method to modify the chemical composition of bio-oils produced via fast pyrolysis.

No abstract

Solid-fuel stoves are at the heart of many homes not only in developing nations, but also in developed regions where there is significant deployment of such heating appliances. They are often operated inefficiently and in association with high emission fuels like wood. This leads to disproportionate air pollution contributions. Despite the proliferation of these appliances, an understanding of particulate matter (PM) emissions from these sources remains relatively low. Emissions from five solid fuels are quantified using a “conventional” and an Ecodesign stove. PM measurements are obtained using both “hot filter” sampling of the raw flue gas, and sampling of cooled, diluted flue gas using an Aerosol Chemical Speciation Monitor and AE33 aethalometer. PM emissions factors (EF) derived from diluted flue gas incorporate light condensable organic compounds; hence they are generally higher than those obtained with “hot filter” sampling, which do not. Overall, the PM EFs ranged from 0.2 to 108.2 g GJ –1 for solid fuels. The PM EF determined for a solid fuel depends strongly on the measurement method employed and on user behavior, and less strongly on secondary air supply and stove type. Kerosene-based firelighters were found to make a disproportionately high contribution to PM emissions. Organic aerosol dominated PM composition for all fuels, constituting 50–65% of PM from bituminous and low-smoke ovoids, and 85–95% from torrefied olive stone (TOS) briquettes, sod peat, and wood logs. Torrefied biomass and low-smoke ovoids were found to yield the lowest PM emissions. Substituting these fuels for smoky coal, peat, and wood could reduce PM 2.5 emissions by approximately 63%.

No abstract

A 42-month investigation from 1996 to 1999 determined that from 211,685 to 576,676 fish were entrained annually at Grand Coulee Dam. Analysis of the entrainment data found that 85% of the total entrainment occurred at the dam's third powerplant. These numbers represent a significant loss to the tribal fisheries upstream of the dam.In response to a suggestion by the NWPPC Independent Scientific Review Panel, the scope of work for the Chief Joseph Kokanee Enhancement Project was expanded to include a multiyear pilot test of a strobe light system to help mitigate fish entrainment. This report details the work conducted during the third year of the strobe light study by researchers of the Colville Confederated Tribes in collaboration with the Pacific Northwest National Laboratory.The objective of the study is to determine the efficacy of a prototype strobe light system to elicit a negative phototactic response in kokanee and rainbow trout under field conditions. The prototype system consists of six strobe lights affixed to an aluminum frame suspended 15 m vertically underwater from a barge secured in the center of the entrance to the third powerplant forebay. The lights, controlled by a computer, illuminate a region directly upstream of the barge.The 2003 study period extended from June 16 through August 1. Three light treatments were used: all six lights on for 24 hours, all lights off for 24 hours, and three of six lights cycled on and off every hour for 24 hours. These three treatment conditions were assigned randomly within a 3-day block throughout the study period.Hydroacoustic technology was used to evaluate the effectiveness of the strobe lights in eliciting a negative phototactic response in fish. The hydroacoustic system in 2003 comprised seven splitbeam transducers arrayed in front of the strobe lights, two multibeam transducers behind the lights, and a mobile splitbeam system. The seven splitbeam transducers were deployed so they tracked fish entering and within the region illuminated by the strobe lights. These transducers were spaced approximately 4 m apart on an aluminum frame floating upstream of the barge and looked vertically downward. The multibeam transducers monitored the distribution of fish directly behind and to both sides of the lights, while the mobile splitbeam system looked at the distribution of fish within the third powerplant forebay.To augment the hydroacoustic data, additional studies were conducted. The hydrodynamic characteristics of the third powerplant forebay were measured, and acoustically tagged juvenile kokanee were released upstream of the strobe lights and tracked within the forebay and downstream of the dam. Strobe Light Deterrent Efficacy Test 2003 Final Report ivAnalysis of the effect of strobe lights on kokanee and rainbow trout focused on the number of fish detected in each of the areas covered by one of the downlooking transducers, the timing of fish arrivals after the status of the strobe lights changed, fish swimming effort (detected velocity minus flow velocity), an...