Emissions of volatile hydrocarbons from floating roof tanks and their local dispersion: Considerations for normal operation and in case of damage

This work investigates the release and dispersion of volatile organic hydrocarbons, which may escape from external floating roof tanks (EFRT) during normal operation or in case of damage. The dispersion will be described using CFD simulations in close range of the EFRT where hazardous areas are assigned. The aim of this work is to investigate which events can lead to emissions in dangerous quantities and to estimate the corresponding likelihood with regard to explosion protection. An emission in hazardous amount is present if the lower explosion limit has been exceeded and if the extent of this emission is not too low. It is discussed in particular whether the used zoning of potentially explosive areas is conservative or over-conservative.     

(Not) talking about justice: justice self-recognition and the integration of energy and environmental-social justice into renewable energy siting

Renewable energy often provokes heated debate on climate change, energy security and the local impacts of developments. However, how far such discussions involve thorough and inclusive debate on the energy and environmental-social justice issues associated with renewable energy siting remains ambiguous, particularly where government agendas prioritise renewable energy and planning systems offer limited opportunities for public debate on value-based arguments for and against renewable energy developments. Using the concept of justice self-recognition, we argue for greater attention to public discussion of the justice dimensions of renewable energy to assist in developing mechanisms to integrate distributive and procedural fairness principles into renewable energy decision-making. To explore how justice is currently invoked in such contexts, we examine recent U.K. policies for renewable energy and public submissions to applications for small-scale wind energy projects in Cornwall, U.K. The analysis of public comments revealed that justice concerns were rarely discussed explicitly. Comments instead did not raise concerns as justice issues or focused implicitly on distributive justice, stressing local aesthetic, community and economic impacts, clean energy and climate change. However, the findings indicated limited discussion of procedural or participatory justice, an absence that hampers the establishment of coherent procedures for deciding acceptable impacts, information standards, public participation and arbitrating disputes. We conclude by suggesting procedural reforms to policy and planning to enable greater public expression of justice concerns and debate on how to negotiate tensions between energy and environmental-social justice in renewable energy siting decisions.     

两个相邻高建筑物周围的风环境

描述研究了建筑物周围人行道高度风速分布特征的风洞模拟实验。结果表明：在一个横风向宽度很大的高大建筑物的迎风面拐角附近，风速增大约１倍；而在建筑物的前方有风速的骤变区，这均形成严重的风环境问题。当用一通道将该建筑物分割成两个相邻建筑物时，上述两方面的风环境问题得到了有效的改善，且通道宽度与建筑物顺风向尺度之比的优化数值在１８至２４之间     

Eight years of annual no-till cropping in Washington's winter wheat-summer fallow region

The tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) cropping system has dominated dryland farming in the Pacific Northwest USA for 125 years. We conducted a large-scale multidisciplinary 8-year study of annual (i.e., no summer fallow) no-till cropping systems as an alternative to WW-SF. Soft white and hard white classes of winter and spring wheat, spring barley (Hordeum vulgare L.), yellow mustard (Brassica hirta Moench), and safflower (Carthamus tinctorius L.) were grown in various rotation combinations. Annual precipitation was less than the long-term average of 301 mm in 7 out of 8 years. Rhizoctonia bare patch disease caused by the fungus Rhizoctonia solani AG-8 appeared in year 3 and continued through year 8 in all no-till plots. All crops were susceptible to rhizoctonia, but bare patch area in wheat was reduced, and grain yield increased, when wheat was grown in rotation with barley every other year. Remnant downy brome (Bromus tectorum L.) weed seeds remained dormant for 6 years and longer to heavily infest recrop winter wheat. There were few quantifiable changes in soil quality due to crop rotation, but soil organic carbon (SOC) increased in the surface 0–5 cm depth with no-till during the 8 years to approach that found in undisturbed native soil. Annual no-till crop rotations experienced lower average profitability and greater income variability compared to WW-SF. Yellow mustard and safflower were not economically viable. Continuous annual cropping using no-till provides excellent protection against wind erosion and shows potential to increase soil quality, but the practice involves high economic risk compared to WW-SF. This paper provides the first comprehensive multidisciplinary report of long-term alternative annual no-till cropping systems research in the low-precipitation region of the Pacific Northwest.     

关于天津台网地震速报的几点思考

本文从地震速报工作的重要性入手，论述了提高地震速报质量的基础和关键，同时讨论了天津台网地震速报中存在影响速报质量的问题及改进措施。     

机器的结构噪声源的特性

从实验上获得结构噪声源描述符,并利用源描述符的概念对不同自由度的结构声源特性进行评价。     

机械回转反吹扁袋除尘器的改进

机械回转反吹扁袋除尘器在使用过程中普遍存在喷吹清灰效果差、回转机构易出故障等问题 ,为了解决这个问题将传统的机械回转机构改为低压脉冲喷吹机构。在此将改进后的除尘器及其应用作以简介     

广州市硫酸盐化速率的灰色GM(1,1)预测

以广州市近7a的硫酸盐化速率年平均值为基础,运用灰色系统理论,建立了广州市硫酸盐化速率年均值的灰色预测模型.用该模型对广州市2005年、2006年、2007年硫酸盐化速率年平均值进行预测,所得结果分别为0.4228、0.4149、0.4070mgSO3/100cm2·碱片·d.     

Estimating fugitive dust emission rates using an environmental boundary layer wind tunnel

Emissions from fugitive dust due to erosion of “natural” wind-blown surfaces are an increasingly important part of PM₁₀ (particulate matter with sizes of 10 μm aerodynamic diameter) emission inventories. These inventories are particularly important to State Implementation Plans (SIP), the plan required for each state to file with the Federal government indicating how they will comply with the Federal Clean Air Act (FCAA). However, techniques for determining the fugitive dust contribution to over all PM₁₀ emissions are still in their developmental stages. In the past, the methods have included field monitoring stations, specialized field studies and field wind-tunnel studies. The measurements made in this paper allow for systematic determination of PM₁₀ emission rates through the use of an environmental boundary layer wind tunnel in the laboratory. Near surface steady-state concentration profiles and velocity profiles are obtained in order to use a control volume approach to estimate emission rates. This methodology is applied to soils retrieved from the nation's single largest PM₁₀ source, Owens (dry) Lake in California, to estimate emission rates during active storm periods. The estimated emission rates are comparable to those obtained from field studies and lend to the validity of this method for determining fugitive dust emission rates.     

Shifted power-law relationship between NO2 concentration and the distance from a highway: A new dispersion model based on the wind profile model

In this paper, a shifted power-law model, based on the wind profile model, had been supposed to simulate concentration gradient of nitrogen dioxide (NO₂) with distance from a highway. Field experiments were performed for NO₂ gradients from a highway in Shanghai by using passive samplers. The shifted power-law model was fitted well with experimental results of field experiments both in this study and in the literature. The results not only verified the validity of shifted power-law relationship between NO₂ concentration and the distance from a highway, but also partially demonstrated that there were some significant similarities between wind profile and air pollutants concentration profile near highway. With known concentration of chosen reference point and appropriate value of the parameter k, the model could be practically applied for predicting the NO₂ distributions near a highway. The methods of determining the parameter k were also discussed for further detailed studies.