Air revitalization compounds: A literature survey

Chemical processes for air revitalization are attractive alternatives for some closed life support systems in the applications of space and marine explorations. A review of the literature is given for the purpose of evaluating potential candidates as air revitalizing chemicals based upon a set of criteria including toxicity in use, removal of airborne contaminants and bacteria, theoretical oxygen yields, chemical reactivity to breathing atmospheres, and commercial availability. The preliminary evaluation shows potassium and sodium Superoxides as prime candidates for further evaluation against the practical considerations of actual use. Upon closer scrutiny, potassium Superoxide is the desired chemical for air revitalization in closed life support systems according to the present technology. Kinetic reaction rates for the simple hydration of KO₂ were reported to increase for increasing pressures to 12 atm making it a promising air revitalization chemical at the hyperbaric conditions encountered in deep diving.     

Precipitator Equipment

The purpose of this section is to set forth the main elements and features of the equipment used for the collection of fly ash. Hardware and structural details of a routine nature having little or no bearing on basic performance are outside the scope of the paper.     

水稻对低磷反应的基因型差异及其生理适应机制的初步研究

选取构建水稻分子连锁图谱的两个亲本ＪＸ１７和ＺＹＱ８为材料,在３低磷胁迫下,对磷营养效率有关指标进行分析,结果表明,ＪＸ１７在与磷吸收效率有关的生理指标,如根干重、根分泌质子、根分泌有机酸等方面,都明显优于ＡＹＱ８,说明ＪＸ１７表现较高的相对干物重,低磷胁迫反应不敏感。     

Adaptive management for mitigating Cryptosporidium risk in source water: A case study in an agricultural catchment in South Australia

Water-borne pathogens such as Cryptosporidium pose a significant human health risk and catchments provide the first critical pollution ‘barrier’ in mitigating risk in drinking water supply. In this paper we apply an adaptive management framework to mitigating Cryptosporidium risk in source water using a case study of the Myponga catchment in South Australia. Firstly, we evaluated the effectiveness of past water quality management programs in relation to the adoption of practices by landholders using a socio-economic survey of land use and management in the catchment. The impact of past management on the mitigation of Cryptosporidium risk in source water was also evaluated based on analysis of water quality monitoring data. Quantitative risk assessment was used in planning the next round of management in the adaptive cycle. Specifically, a pathogen budget model was used to identify the major remaining sources of Cryptosporidium in the catchment and estimate the mitigation impact of 30 alternative catchment management scenarios. Survey results show that earlier programs have resulted in the comprehensive adoption of best management practices by dairy farmers including exclusion of stock from watercourses and effluent management from 2000 to 2007. Whilst median Cryptosporidium concentrations in source water have decreased since 2004 they remain above target levels and put pressure on other barriers to mitigate risk, particularly the treatment plant. Non-dairy calves were identified as the major remaining source of Cryptosporidium in the Myponga catchment. The restriction of watercourse access of non-dairy calves could achieve a further reduction in Cryptosporidium export to the Myponga reservoir of around 90% from current levels. The adaptive management framework applied in this study was useful in guiding learning from past management, and in analysing, planning and refocussing the next round of catchment management strategies to achieve water quality targets.     

Morphological Changes in Poly(Caprolactone)/Poly(Vinyl Chloride) Blends Caused by Biodegradation

The biodegradation of blends of poly(caprolactone) (PCL) and poly(vinyl chloride) (PVC) has been studied. Blends of composition PCL/PVC 1:1 and 1:2 w/w were tested. The 1:1 blend contained crystals in the as-cast state and became more crystalline on exposure to different bio-active agents. The 1:2 blend was amorphous in the as-cast state but developed a significant crystal component after 4 months exposure to the bio-agents. Three bio-active agents were used and all were found to produce qualitatively similar behaviour but their activity was somewhat different. For both the 1:1 blend and the 1:2 blend the ranking of the three bio-active agents tested, in increasing order, was Curvularia sp.; Trogia buccinalis; Phanerochaete chrysosporium.     

Blue space: The importance of water for preference,affect, and restorativeness ratings of natural and built scenes

Although theorists have suggested that aquatic environments or “blue space” might have particular restorative potential, to date there is little systematic empirical research on this issue. Indeed the presence of water has, unintentionally, been a confounding factor in research comparing people’s reactions to built and natural environments. Whereas aquatic features (rivers, lakes, coasts) are frequently present in visual stimuli representing natural environments they are rarely incorporated in stimuli portraying built environments. As many towns are, for good reason, located near water this is a potentially significant oversight. The current research collated a set of 120 photographs of natural and built scenes, half of which contained “aquatic” elements. Proportions of “aquatic”/“green”/“built” environments in each scene (e.g. 1/3rd, 2/3rds) were also standardised. Two studies investigated preferences (attractiveness, willingness to visit and willingness to pay for a hotel room with the view), affect and perceived restorativeness ratings for these photographs. As predicted, both natural and built scenes containing water were associated with higher preferences, greater positive affect and higher perceived restorativeness than those without water. Effect sizes were consistently large. Intriguingly, images of “built” environments containing water were generally rated just as positively as natural “green” space. We propose a number of avenues for further research including exploration of the mechanisms underlying these effects.     

Comparison of a two-dimensional numerical dust transport model with experimental dust emissions from soil surfaces in a wind tunnel

Near-surface wind-tunnel fugitive dust concentration profiles arising from soil surfaces beds were compared to a finite difference numerical dust transport model. Comparisons of the type shown in this study were previously non-existent in the literature due to the lack of experimental wind-tunnel data for near-surface concentrations over a soil bed. However, in a previous study by the authors, near-surface steady-state concentration profiles were measured in order to obtain fugitive dust emission rates, thus allowing the comparison to models shown in this paper. The novel aspects of the current study include: comparison of concentration profiles of dust obtained experimentally in the wind tunnel with those calculated numerically; comparison of the calculated numerical fetch effect on dust emissions with that obtained in the wind tunnel; and comparison of the emission rates calculated numerically with those obtained experimentally in the wind tunnel. Initial comparisons with the model indicate good agreement implying that the physical mechanism of advection–diffusion is reasonably modeled with the choice of equations for the simple “steady-state” process near the surface. Furthermore, the numerical solutions presented in this paper provide a means to systematically explore the relative impact of varied surface boundary conditions upon the emission process and provide a potential link between wind-tunnel simulations and field scale models.     

东南亚珠芽魔芋多苗接力生长特性及应用前景

以珠芽魔芋人工诱导开花进行规模化无性育种,可将魔芋繁殖系数从1位数提高约330倍;采用催苗技术让种子及叶面球茎提早出苗,可显著延长魔芋生长周期,使魔芋种植周期由3年缩短为1年;魔芋种子1年生长最高膨大率超过5000倍,当年即形成1180g球茎;魔芋叶面球茎最大膨大率超过100倍,两者种植一季魔芋即可用于加工.突破了魔芋繁殖系数低、膨大率低导致种植周期长的双重困局,显著降低了病害风险,大幅度缩短了魔芋种植周期,从而突破魔芋传统种植区域的地理限制,使魔芋总产量超常规增长.