Concentration and extraction of phosphorus from swine manure slurries as struvite

The objective of this research was to address the application of dedicated struvite reactors for full-scale pork production operations by: (1) Investigating a method that quickly identifies maximum struvite precipitation, accounting for real-time variations of magnesium demand within the manure slurries. (2) Developing and testing a short-retention-time pilot-scale reactor that: (a) Effectively and reliably reduces DRP in a variety of swine manure slurries; (b) Provides separation and recovery of precipitated struvite for TP reduction; (c) Can be effectively applied to modern pork production systems across a variety of manure management systems

Effects of the Burrowing Brittlestar, Microphiopholis gracillima (Echinodermata: Ophiuroidea), on the Flux of Lithium, an Inert Tracer, Across the Sediment-Water Interface

Burrowing and ventilation activities of infaunal organisms have been shown to affect geochemical processes in sediments and at the sediment-water interface. Although burrowing brittlestars are dominant in many benthic environments, their role in these processes is poorly known. We tested the effect of the amphiurid brittlestar, Microphiopholis gracillima, on the flux of lithium ion from the sediment to the overlying water by using sediment cores with false bottoms for continuous flow of a Li+1-seawater solution. Brittlestars at densities of 300 and 600 individuals m-2 caused a twofold increase in the rate that Li was transported through the sediment. Density of brittlestars appeared to have no effect on the flux of Li+1 from the sediment, indicating a possible threshold beyond which density increases do not influence fluxes of solute from the sediment

Pulsed laser deposition for growth of high quality epitaxial garnet films for low threshold waveguide lasers

Pulsed laser deposition (PLD) is a mature technique capable of producing extremely high quality epitaxial single crystalline films. We have grown Nd:doped garnet films of GGG (Gd The talk will summarise our progress using conventional (single beam) PLD in thin-film and waveguide growth, using both nanosecond and femtosecond lasers, and also introduce our new directions in tri-beam PLD (three targets, three lasers) for growth of some interesting, complex and perhaps impossible structures, such as Gaussian doping, internal voids and even helically doped structures

Concentrations of Ammonia, Greenhouse Gases and Particulate Matters in Conventional Cage, Aviary, and Enriched Colony Laying-Hen Houses

Research concerning comparative environmental impacts between conventional cage and emerging alternative laying-hen housing systems is relatively limited under US production conditions. As an integral part of the Coalition for Sustainable Egg Supply (CSES) project, a 27-month continual environmental monitoring (covering two single-cycle flocks) described in this paper quantifies the indoor gaseous and particulate matter (PM) concentrations, thermal environment, and housing ventilation rate (VR) for a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. Results show that indoor temperature and relative humidity (RH) in all three houses were well maintained through proper ventilation management and supplemental heat in wintertime (AV house only). Daily mean(±SD) indoor ammonia (NH3) concentrations were 4.3(±2.6) ppm for CC house, 7.1(±6.3) ppm for AV house, and 2.8(±1.8) ppm for EC house. The NH3 concentrations in the AV house were significantly higher than those in CC or EC house, and occasionally exceeded 25 ppm under cold weather conditions (ambient temperature <7.2°C). Daily mean(±SD) indoor carbon dioxide (CO2) and methane (CH4) concentrations were, respectively, 2153(±1058) and 11.1(±5.7) ppm for CC house, 2485(±1268) and 11.6(±5.5) ppm for AV house, and 2241(±1145) and 11.8(±5.9) ppm for EC house. The particulate matter (PM) concentrations in AV house were significantly higher than those in CC or EC house. Daily mean (±SD) concentrations of PM10 and PM2.5 were, respectively, 0.59(±0.16) and 0.035(±0.013) mg m-3 for CC house, 3.95(±2.83) and 0.410(±0.251) mg m-3 for AV house, 0.44(±0.18) and 0.056(±0.021) mg m-3 for EC house. Overall, indoor air quality of the EC house was comparable with that of the CC house; however, the AV house experienced poor indoor air quality, especially during cold weather, resulting from the presence of floor litter and hens activities on it. Therefore searching for mitigation practices to improve indoor air quality in AV housing system is needed.</p

Results of 1/4-Scale Experiments. Vapor Simulant And Liquid Jet A Tests

A quarter-scale engineering model of the center wing tank (CWT) of a 747-100 was constructed. This engineering model replicated the compartmentalization, passageways, and venting to the atmosphere. The model was designed to scale the fluid dynamical and combustion aspects of the explosion, not the structural failure of the beams or spars. The effect of structural failure on combustion was examined by using model beams and spars with deliberately engineered weak connections to the main tank structure. The model was filled with a simulant fuel (a mixture of propane and hydrogen) and ignited with a hot wire. The simulant fuel was chosen on the basis of laboratory testing to model the combustion characteristics (pressure rise and flame speed) of Jet A vapor created by a Jet A liquid layer at 50C at an altitude of 13.8 kft. A series of experiments was carried out in this model in order to: (a) investigate combustion in a CWT geometry; and (b) provide guidance to the TWA 800 crash investigation. The results of the experiments were observed with high-speed film, video, and still cameras, fast and slow pressure sensors, thermocouples, photodetectors, and motion sensors. A special pseudo-schlieren system was used to visualize flame propagation within the tank. This report describes the test program, facility, instrumentation, the first 30 experiments, comparisons between experiments, and performance of the instrumentation; then examines the significance of these results to the TWA 800 crash investigation. The key results of this study are: Flame Motion: The motion of flame was dominated by the effects of turbulence created by jetting through the passageways and vent stringers. A very rapid combustion event (lasting 10 to 20 ms) occurred once the flame traveled outside of the ignition bay and interacted with the turbulent flow. Most of the gas within the tank was burned during this rapid event. Compartments: The combustion time decreased with an increasing number of compartments (bays) within the tank. With six bays, combustion took only 100 to 150 ms to be completed from the time of ignition until the end of the rapid combustion phase. The total combustion event was three to four times shorter with compartments than without. Venting: Venting to the outside of the tank through the model vent stringers had a negligible effect on the combustion progress or on the peak pressure reached at the end of the burn. Ignition Location: Variation of the ignition location produced distinctive pressure loads on the structural components. Liquid Fuel: Lofting of a cold liquid fuel layer was produced by the combustion-induced gas motion. Although this spray of liquid eventually ignited and burned, it did not contribute to the pressure loading. Structural Failure: Structural failure resulted in flame acceleration, decreasing the overall combustion time. TWA 800 Investigation: The pressure loads were sufficiently high, up to 4 bar, and the combustion events were sufficiently short, that the forward portion (spanwise beam 3, front spar) of the CWT structure would fail as a direct consequence of the explosion. A combination of pressure loads was produced in some tests consistent with the TWA 800 wreckage. Replica tests, structural modeling, and sensitivity studies on fuel concentration are needed before any conclusions can be drawn about probable ignition locations. Cargo Bay: Tests with a simplified model of a half-full cargo bay indicated that repeated pressure waves with an amplitude of 1 bar or less are produced when an explosion scenario similar to TWA 800 is tested. Future Testing: Future studies should include replica tests, tests with Jet A vapor and warm liquid Jet A layers, and sensitivity tests to examine ignition location, fuel concentration, and vent area perturbations. Summary: Explosion tests in a 747-100 CWT model reveal that a very complex pattern of combustion occurs due the interaction of the flame and the flow-generated turbulence. A wide range of structural load patterns occur, depending on the location of the ignition source. Some of these load patterns are consistent with damage believed to be associated with the initial explosion event in TWA 800. Sensitivity of the loading to the ignition location indicates that narrowing down the ignition location in TWA 800 may be possible. However, the complexity of the combustion and structural failure processes in the actual center wing tank mandates extremely careful consideration of the uncertainties that enter into this process

Determination of Minimum Horizontal Distance between Laying-Hen Perches

The objective of the study was to determine minimum horizontal distance (HD) between perches for laying hens using qualitative and quantitative behavioral analysis. A real-time monitoring system was developed to record hen’s perching behaviors, such as the number of perching hens, perching duration, perching trips, and the pattern of perch occupancy. Three groups of sixteen W-36 laying hens (68 weeks old at test onset) with prior perching experience were used. For each group, hens were kept in an enriched wire-mesh floor pen (1.2×1.2×1.2m) equipped with two parallel perches (15 cm perch space/hen). The HD between the perches were varied sequentially at 60, 40, 30, 25, 20, and 15 cm; then varied again in a reversed order. The minimum HD that led to no significant change in hen’s perching behavior was determined. Results showed that reduction of HD to 25 cm did not significantly restrain hen’s perching behavior; however, HD \u3c25 cm significantly reduced the proportion of perching hens. When HD was insufficient, more perching trips occurred during the 45 min prior to dark period, indicating increase in perching competition. Meanwhile, hens perched interlacing with one another and tended to perch outwards from the opposite perch or hens during dark period, which might be a strategy to use the perch more efficiently. Horizontal distance of 60 cm increased the perching duration and reduced the perching trips during light period; however these two behavioral responses were not affected by HD \u3c60 cm. Therefore, 25 cm is suggested as the minimum HD between laying-hen perches, 30 cm being preferable, and large HD’s such as 60 cm not advisable

Environmental assessment of three egg production systems—Part I: Monitoring system and indoor air quality

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens’ activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted