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

Optimizing Tunnel Ventilation Systems for Summer Conditions

Tunnel ventilation is a popular choice for livestock housing systems as it allows producers to elevate the wind speed across the animals to increase heat dissipation during summer conditions. Recent work with tunnel-ventilated facilities has shown that at maximum ventilation stage the building static pressure (SP) often exceeds 0.12 inches of H2O. The effects of reducing SP on electrical consumption and ventilation performance were investigated. Decreasing SP of the tunnel-ventilated barn increased the overall ventilation rate, increased air velocity within the barn, and decreased the temperature rise along the length of the barn. From May to September, maintaining a SP between 0.04 and 0.08 inches of water column (W.C. or H2O) showed a potential energy savings of $300 to$570 for an 1800-sow gestation barn. Properly sizing and managing air inlets for summer ventilation is an inexpensive and quick modification that can better alleviate heat stress and reduce electrical consumption

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

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

Thin-shell textile-reinforced concrete floors for sustainable buildings

Steel-reinforced concrete, cast in flat prismatic forms, dominates multi-storey building construction around the world. Despite the fluidity of the material, opportunities to create efficient geometries through manipulation of form are habitually overlooked, resulting in inefficient cracked sections, high steel requirements and large carbon footprints. This project brings together modern developments in computational design, materials and construction to propose a novel thin-shell concrete flooring system for multi-storey buildings, creating a low embodied energy and lightweight alternative to traditional reinforced concrete flat slabs. In this investigation, the performance of various shell geometries are compared using finite element analysis. A functional design is produced and found to offer reductions of 62% in embodied energy and 64% in weight compared to an equivalent flat slab

Perch-shape preference and perching behaviors of young laying hens

Provision of perches in enriched colony or cage-free hen housing facilitates birds’ ability to express natural behaviors, thus enhancing animal welfare. Although considerable research has been conducted on poultry perches, further investigation is needed of perching behavior and preference of laying hens to perch exposure and perch types. This study aimed to assess preference of young laying hens for round vs. hexagon perches and to characterize temporal perching behaviors of the young hens brought to an enriched colony setting from a cage pullet-rearing environment. A total of 42 Lohmann white hens in six equal groups, 17 weeks of age at the onset of the experiment, were used in the study. Each group of hens was housed in a wire-mesh floor pen equipped with two 120 cm long perches (one round perch at 3.2 cm dia. and one hexagon perch at 3.1 cm circumscribed dia., placed 40 cm apart and 30 cm above the floor). Each group was monitored continuously for 9 weeks. Perching behaviors during the monitoring period, including perching time, perch visit, and perching bird number, were recorded and analyzed daily using an automated perching monitoring system. Results revealed that the laying hens showed no preference between the round and hexagon perches (P = 0.59–0.98). Young laying hens without prior perching experience showed increasing use of perches over time (P \u3c 0.01). It took up to five to seven weeks of perch exposure for young hens to show consistent perching behaviors in the enriched colony setting. This study also found that laying hens spent about 10% of daytime on the perches and over 75% of hens perched at night after approaching consistent perching behaviors. In general, the results supplemented to the existing knowledge base for the quantitative behavior study on laying hens’ temporal perch use

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