日光辐射对大气真菌粒子的影响

大气中真菌粒子的衰亡和净化，除与真菌自身的因素有关外，与日光辐射也有密切关系。此文现场观测了日光辐射对大气真菌粒子的影响。结果表明，一天内大气真菌粒子浓度与日光辐射强度呈反比：大气真菌粒数直径中值与日光辐射强度呈正比：随着日光辐射强度的增大，＜３．０μｍ的大气真菌粒子，其浓度减小的速度比＞３．０μｍ的快。     

PV_1、B.fp在不同水样及温度条件下的灭活动力学

研究了脊髓灰质炎病毒 (Poliovirus1,PV1)、脆弱拟杆菌噬菌体 (bacteriophageinfectingBacteroidesfragilis,B .fp)在不同水样 (自来水、超纯水、闽江水、生活污水和滤膜过滤除菌生活污水 ) ,不同温度 (4℃、2 0℃、35℃ )条件下的灭活动力学 .结果显示 :温度是导致病毒灭活的重要因素 ,温度升高 ,病毒灭活速率加快 .同时 ,某些水质因子也明显影响病毒的灭活 .实验结果还表明 ,在任一灭活实验条件下 ,B .fp的灭活速率都比PV1低 ,表明B .fp是一个更合适的用于指示水体病毒污染程度与灭活效率的指示生物 .图 4表 2参 2 1     

Photocatalytic treatment of dimethoate by solar photocatalysis at pilot plant scale

Titanium dioxide photocatalysis, using 200 mgl⁻¹ of TiO₂, and photo-Fenton, using 20 mg l⁻¹ of iron, were applied to the treatment of dimethoate dissolved in water at 50 mg l⁻¹. A heterogeneous photocatalysis test was performed in a 35-l solar pilot plant with Compound Parabolic Collectors (CPCs) under natural illumination. A homogeneous photocatalysis test was performed in a different solar pilot plant with four CPC units and a total volume of 75 l. In this work total disappearance of dimethoate and 90% of mineralization were attained in both solar treatments. Treatment time, hydrogen peroxide consumption and ferric phosphate precipitation during photo-Fenton treatment were discussed. An erratum to this article can be found at     

Effects of soiling and cleaning on the reflectance and solar heat gain of a light-colored roofing membrane

A roof with high solar reflectance and high thermal emittance (e.g., a white roof) stays cool in the sun, reducing cooling power demand in a conditioned building and increasing summertime comfort in an unconditioned building. The high initial solar reflectance of a white membrane roof (circa 0.8) can be lowered by deposition of soot, dust, and/or biomass (e.g., fungi or algae) to about 0.6; degraded solar reflectances range from 0.3 to 0.8, depending on exposure. We investigate the effects of soiling and cleaning on the solar spectral reflectances and solar absorptances of 15 initially white or light-gray polyvinyl chloride membrane samples taken from roofs across the United States. Black carbon and organic carbon were the two identifiable strongly absorbing contaminants on the membranes. Wiping was effective at removing black carbon, and less so at removing organic carbon. Rinsing and/or washing removed nearly all of the remaining soil layer, with the exception of (a) thin layers of organic carbon and (b) isolated dark spots of biomass. Bleach was required to clear these last two features. At the most soiled location on each membrane, the ratio of solar reflectance to unsoiled solar reflectance (a measure of cleanliness) ranged from 0.41 to 0.89 for the soiled samples; 0.53 to 0.95 for the wiped samples; 0.74 to 0.98 for the rinsed samples; 0.79 to 1.00 for the washed samples; and 0.94 to 1.02 for the bleached samples. However, the influences of membrane soiling and cleaning on roof heat gain are better gauged by fractional variations in solar absorptance. Solar absorptance ratios (indicating solar heat gain relative to that of an unsoiled membrane) ranged from 1.4 to 3.5 for the soiled samples; 1.1 to 3.1 for the wiped samples; 1.0 to 2.0 for the rinsed samples; 1.0 to 1.9 for the washed samples; and 0.9 to 1.3 for the bleached samples.     

Comparison study and parameter identification of three battery models for an off-grid photovoltaic system

There is growing interest in solar batteries, especially for photovoltaic (PV) applications. Therefore, an accurate battery model is required for the PV system because of its influence on system efficiency. Several mathematical models of batteries have been described in the scientific literature. However, this paper reviews three electrochemical models most commonly used for PV systems, such as Shepherd, Manegon and Coppetti, in order to define the most appropriate model for PV systems. This paper discusses an application of the pattern search optimization technique to extract the parameters of three battery models derived from experimental test results obtained from sealed gelled lead acid batteries for both charge and discharge modes. A comparative case and regression analysis based on statistical tests and a quantitative method were conducted to demonstrate the effectiveness and accuracy of the updated model from the three aforementioned. The simulation results and tests performed on the battery charge and discharge modes lead us as well to approve the algorithm’s accuracy regarding the updated model.     

Experimental investigation of solar still with opaque north triangular face

Developing a compact, simple, and productive solar still is a main challenge. This paper describes a simple modification of the solar still that significantly enhances its productivity. A laboratory scale of modified single effect double slope glass solar still with the opaque triangular north wall has been developed and tested for enhancement of productivity in sunny days of the summer season in the month of April. The experiments on still have been carried out under three levels of water depths from 1 to 3 cm and compared it with the performance of conventional still of double slope single effect solar still of the same size. It is clear from the observations that opaque type still gave maximum distillate of 1793 ml at 1 cm depth of water while conventional still could produce only 1519 ml for the same depth of water. Also, for 2 and 3 cm depth of water, the opaque type still found to be more productive than conventional double slope solar still. As the former produced 1532 and 1464 ml while the latter produced 1328 and 1235 ml, for 2 and 3 cm depth of water, respectively.     

Do lower electricity storage costs reduce greenhouse gas emissions?

In the electricity sector, innovation in large-scale storage is anticipated to reduce costs and improve performance. The effect on greenhouse gas emissions of lower storage costs depends on the interactions between storage and the entire grid. The literature has disagreed on the role of storage in reducing emissions. In this paper we present a stylized model, which suggests that the effect of storage costs on emissions depends on the supply responsiveness of both fossil and renewable generators. Under common conditions in the United States, lower storage costs are more likely to reduce emissions when wind investment responds to equilibrium electricity prices and when solar investment does not. Simulations of a computational model of grid investment and operation confirm these intuitions. Moreover, because of its effect on coal and natural gas–fired supply responsiveness, introducing a carbon dioxide emissions price may increase the likelihood that lower storage costs reduce emissions.     

Degradation of Carbofuran in Water by Solar Photocatalysis in Presence of Photosensitizers

The effect of the presence of photosensitizers, methylene blue (MB) and rose Bengal (RB), on the degradation of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) in water in a solar photocatalytic system was investigated. It was found that as compared to MB, RB generally showed a stronger effect on the decomposition of carbofuran under comparable conditions. Among the conditions studied, adding 2 × 10^?6 M of RB, that corresponding to 2% of the initial concentration of carbofuran solution in the system, rendered the most effective degradation of carbofuran. As a result, a carbofuran removal percentage of 69.9%, a mineralization efficiency of 28.0%, and a microtoxicity reduction of 65.0% could be achieved. The degradation and mineralization of carbofuran was found to follow the pseudo-first order reaction kinetics. The decomposition mechanism of carbofuran was further investigated through identification of the intermediates to elaborate the influence of dye photosensitizer on the solar photocatalysis of carbofuran in water. On the basis of the intermediates identified, including carbofuran phenol, 3-hydroxy carbofuran phenol, and substituted alcohols (3-phenoxy 1-propanol, 2-ethyl 1-hexanol, 2-butoxyl ethanol), it appears that hydrolysis and hydroxylation were the two key mechanisms for decomposing carbofuran during the process of solar photocatalysis with the aid of dye photosensitizer.     

日地环境对人类自发攻击性事件的影响

考察了日地空间物理环境扰动与人类自发攻击性群体性事件发生率之间相关性。统计分析发现，两者之间的相关程度很高，历元叠加后相关系数可达０．８４和０．７９、这表明日地空间物理环境对人类攻击性本能和情绪具有显著的调节作用，导致全球自发攻击性群体事件年发生率具有１１ａ准周期波动特征。其作用机制可能是地磁场活动和大气温度的影响。     

Influence of Geoengineered Climate on the Terrestrial Biosphere

Various geoengineering schemes have been proposed to counteract anthropogenically induced climate change. In a previous study, it was suggested that a 1.8% reduction in solar radiation incident on the Earths surface could noticeably reduce regional and seasonal climate change from increased atmospheric carbon dioxide (CO₂). However, the response of the terrestrial biosphere to reduced solar radiation in a CO₂-rich climate was not investigated. In this study, we hypothesized that a reduction in incident solar radiation in a Doubled CO₂ atmosphere will diminish the net primary productivity (NPP) of terrestrial ecosystems, potentially accelerating the accumulation of CO₂ in the atmosphere. We used a dynamic global ecosystem model, the Integrated Biosphere Simulator (IBIS), to investigate this hypothesis in an unperturbed climatology. While this simplified modeling framework effectively separated the influence of CO₂ and sunlight on the terrestrial biosphere, it did not consider the complex feedbacks within the Earths climate system. Our analysis indicated that compared to a Doubled CO₂ scenario, reduction in incident solar radiation by 1.8% in a double CO₂ world will have negligible impact on the NPP of terrestrial ecosystems. There were, however, spatial variations in the response of NPP-engineered solar radiation. While productivity decreased by less than 2% in the tropical and boreal forests as hypothesized, it increased by a similar percentage in the temperate deciduous forests and grasslands. This increase in productivity was attributed to a 1% reduction in evapotranspiration in the Geoengineered scenario relative to the Doubled CO₂ scenario. Our initial hypothesis was rejected because of unanticipated effects of engineered solar radiation on the hydrologic cycle. However, any geoengineering approaches that reduce incident solar radiation need to be thoroughly analyzed in view of the implications on ecosystem productivity and the hydrologic cycle.