Safety studies on hydraulic proportional valves with electrical position feedback.

The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Several failures were introduced into the feedback loop, especially into the 2 solenoids and the inductive position transducer. The behaviour of the valve for square and ramp reference signals was recorded and systematically analysed. It was shown that failures could be detected by monitoring the residual signal from the equipment under control or the residual signal from the sensor. It was possible to achieve the safe position within twice the normal response time of the valve by switching off the current of both solenoids. The application of these results for a new generation of safe proportional valves is discussed. The use of the results of these investigations obviates the need for redundancy of the electrical position monitoring arrangement in a safe proportional valve.     

Modeling alkene chemistry using condensed mechanisms for conditions relevant to southeast Texas,USA

Alkenes are important in photochemical smog formation in southeast Texas due to their high emissions, especially from industrial sources in and around Houston, and their high reactivities. Therefore, properly characterizing the chemistry of alkenes in condensed mechanisms used in regional photochemical models is important in understanding the formation of ozone and other photochemical air pollutants in Houston. The performance of three versions of the SAPRC condensed chemical mechanism family, for predicting ozone and radical formation, was compared. Simulations were compared to environmental chamber data and ambient data. The analyses showed that separately modeling individual alkenes reactions (especially propene for southeast Texas) has the potential to lead to more accurate simulations of alkene chemistry. Caution must be exercised in un-lumping, however. Testing with different formulations of the 1-butene + O₃ reaction demonstrated the complexity and interconnectedness in choices of stoichiometric parameters for un-lumped species and the extent to which lumped mechanisms are un-lumped.     

Effects of Land Use Data on Dry Deposition in a Regional Photochemical Model for Eastern Texas

ABSTRACT

Land use data are among the inputs used to determine dry deposition velocities for photochemical grid models such as the Comprehensive Air Quality Model with extensions (CAMx) that is currently used for attainment demonstrations and air quality planning by the state of Texas. The sensitivity of dry deposition and O₃ mixing ratios to land use classification was investigated by comparing predictions based on default U.S. Geological Survey (USGS) land use data to predictions based on recently compiled land use data that were collected to improve biogenic emissions estimates. Dry deposition of O₃ decreased throughout much of eastern Texas, especially in urban areas, with the new land use data. Predicted 1-hr averaged O₃ mixing ratios with the new land use data were as much as 11 ppbv greater and 6 ppbv less than predictions based on USGS land use data during the late afternoon. In addition, the area with peak O₃ mixing ratios in excess of 100 ppbv increased significantly in urban areas when deposition velocities were calculated based on the new land use data. Finally, more detailed data on land use within urban areas resulted in peak changes in O₃ mixing ratios of ~2 ppbv. These results indicate the importance of establishing accurate, internally consistent land use data for photochemical modeling in urban areas in Texas. They also indicate the need for field validation of deposition rates in areas experiencing changing land use patterns, such as during urban reforestation programs or residential and commercial development.     

Safety Studies on Hydraulic Proportional Valves With Electrical Position Feedback

The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Severalfailures were introduced into the feedback loop, especially into the 2 solenoids and the inductive positiontransducer. The behaviour of the valve for square and ramp reference signals was recorded and systematicallyanalysed. It was shown that failures could be detected by monitoring the residual signal from the equipmentunder control or the residual signal from the sensor. It was possible to achieve the safe position within twice thenormal response time of the valve by switching off the current of both solenoids. The application of these resultsfor a new generation of safe proportional valves is discussed. The use of the results of these investigationsobviates the need for redundancy of the electrical position monitoring arrangement in a safe proportionalvalve.     

Rare earth element content in various waste ashes and the potential risk to Japanese soils.

Selected chemical characteristics of rare earth elements (REEs) in 89 waste ash samples, including food scrap ashes (FSA), animal waste ashes (AWA), horticulture waste ashes (HWA), sewage sludge ashes (SSA) and incinerator bottom ashes (IBA), were examined in this study. The results showed that Y, La, Ce, Pr, Nd, Dy, Yb, Ho, Er, Tm, Lu in the waste ash samples were normally distributed, but Sc, Sm, Eu, Gd, Tb were not. Average REE concentrations followed the sequence of Ce > La = Y> Sc>Nd>Sm>Pr>Gd>Dy>Eu>Tb>Er> Yb>Ho>Lu>Tm. Of the five types of waste ashes, total REE contents (sigmaREE) ranged from 54 to 130 mg/kg, following the sequence of SSA>HWA>IBA>AWA>FSA; individual REE concentrations were within 0.04-20, 0.1-29, 0.2-33, 0.1-44 and 0.01-41 mg/kg for FSA, AWA, HWA, SSA and IBA, respectively. Crust-normalized REE patterns indicated that SSA was enriched with Sc, Sm, Eu, Gd, Tb and slightly enriched with La, Ce; IBA was enriched with Eu, Tb and slightly with La, Y, Ce; FSA was slightly enriched with Sm, Eu, Tb; REEs were not found to be elevated in HWA and AWA. Comparison of REE content in the waste ashes and in six principal Japanese agricultural soils indicated that application of FSA, AWA and HWA to agricultural land will cause no REE problem, but continuous application of SSA or IBA may cause Sc, Sm or Eu accumulation in some of the soils.     

Motorcycle recycling flow and end-of-life motorcycles in Japan

Journal of Material Cycles and Waste Management - This study compiled the number of End-of-Life motorcycles (ELMCs), utilizing Japanese official motorcycle data to clarify “the...     

Sanitation of seawater effluent from seaweed processing plants using a photo-catalytic TiO2 oxidation

A fine porcelain open-cell photo-catalytic filter with titanium dioxide (TiO(2)) was evaluated for sterilization and sanitation of bio-polluted industrial water. In simulated seawater industrial effluent samples, the populations of Escherichia coli and Vibrio parahaemolyticus quickly decreased and reached non-detectable level within 10min. In seawater effluents from a seaweed processing plant, the bacterial populations in two samples quickly decreased by more than 10(3). In another two samples the decreases were slow and lowered by less than 10(2). Using fluorescence microscopy, it was indicated that the bacterial cells treated with photo-catalytic TiO(2) were damaged. In addition, the protein concentration in simulated seawater effluent slowly decreased using the photo-catalytic TiO(2) reaction; and reached similar concentrations as seawater near cultured seaweed beds. These results indicate that using a reactor with a TiO(2) photo-catalyst filter was effective for the sanitation of seawater effluents.     

Dissolution of polystyrene into cyclic monoterpenes present in tree essential oils

We examined dissolution of polystyrene (PS) into cyclic monoterpenes present in tree essential oils, in order to develop an environmentally friendly shrinking agent for expanded polystyrene. The relationship between the chemical structure of the monoterpenes and their dissolution power for PS was studied through the solubility parameter (δ) and apparent activation energy (E _a) for dissolution. (R)-Limonene and its structural isomers on a C=C bond have high solvent power for PS. This favorable solubility was explained by their solubility parameters. The occurrence of hydroxyl group in a solvent molecule, such as in terpinen-4-ol, reduced affinity for PS. Bicyclic monoterpenes and 1,8-cineole, which have sterically bulky structure, showed limited dissolution power even though they have solubility parameters similar to that of (R)-limonene. Their bulky structures would interfere with permeation of solvent into the PS matrix. Cyclic monoterpenes and PS were recovered almost quantitatively by simple steam distillation of the PS solution.     

盐碱胁迫对水稻幼苗中基因差异表达的影响

为了阐明已分离的盐碱适应性相关基因(Liuetal, 2000)的表达特性,以14d叶龄的水稻品种日本晴幼苗为材料,分别经NaHCO3 (60mmol/L,pH8. 50) )处理6h、12h、24h、48h, 及不同pH值(pH4. 50, 6. 50, 8. 50, 10. 50)的NaCl(100mmol/L), NaHCO3 (60mmol/L)和Na2CO3 (30mmol/L)处理24h, 以分析时间效应及浓度与pH值间的联合效应. 结果表明,与对照(H2O, pH6. 50)相比较,NaHCO3 (60mmol/L)处理6h、12h、24h、48h后,mitochondrialAT Pase6×103的转录本分别提高2. 73、0. 82、0. 01和1. 79倍;cAPX转录本在24h和48h较对照提高1. 17和1. 49倍;处理6h后CA和HSP90基因表达受显著抑制;UDPG-GT增强表达的滞后期为6h;thioredoxin受NaHCO3轻微抑制.不同pH值和24h处理条件下,NaHCO3和Na2CO3显著促进mitochondrialATPase6×103基因表达.CA基因表达受Na 、HCO-3 和pH的共同影响;而thioredoxin主要受Na 和pH的双重影响; cAPX也表现出类似趋势.UDPG-GT在Na2CO3处理中表达量最高,HSP90的表达随pH的升高而降低. 图6表2参13     

Effects of the driftwood Richardson number and applicability of a 3D–2D model to heavy wood jamming around obstacles

Environmental Fluid Mechanics - Predicting the motion of driftwood around hydraulic structures such as bridge piers and spur dikes is important. We propose a numerical model for simulating...