The effect of greenhouse vegetation coverage and area on the performance of an earth-to-air heat exchanger for heating and cooling modes

The underground temperature at a depth of about 3–4 m is almost constant all the year round. In summer, the underground temperature is lower than the ambient temperature, but in winter it is vice versa. This potentiality is considered for greenhouse cooling and heating by using an earth-to-air heat exchanger (EAHE). This paper considers the effects of two parameters as independent variables including the area of greenhouse and the percentage of vegetation coverage inside the greenhouse on the performance of an EAHE system during both cooling and heating modes. The inside temperature, the thermal energy exchange and the coefficient of performance (COP) of the system were considered as dependent variables. The results showed that both greenhouse area and the percentage of vegetation coverage inside the greenhouse had significant effects on the performance of the EAHE system during both cooling and heating modes. However, the COP of the EAHE system was higher in the cooling mode (4.32) than during the heating mode (1.01). The percentage of vegetation coverage negatively affected the performance of the EAHE system in the cooling mode. However, the performance of the EAHE system improved with the increase in the percentage of vegetation coverage during the heating mode.     

高温堆肥法处理污泥的探讨

对于污水处理后所产生的污泥,较好的方法是采用无害化、资源化农用技术,利用污泥为原料,制成有机复合肥,不仅解决了污水污泥的处理问题,还可推动环保产业的发展,促进农业生产,具有明显的经济、社会和环境效益。     

CHANGING RAINFALL-RUNOFF RELATIONSHIPS IN THE URBANIZING PEACHTREE CREEK WATERSHED,ATLANTA, GEORGIA1

ABSTRACT: Peachtree Creek is a gaged watershed that has experienced a substantial increase in urbanization. The relationships of runoff to rainfall were studied for total annual flows, low flows, and peak flows. For each type of flow the relationship in the later, more urbanized period was compared to that in the earlier, less urbanized period. An increase in total runoff in wet years was observed as urbanization increased, but a decrease occurred during dry years. For low flows a similar decrease of runoff in dry years was found. An increase in peak runoff was observed over most of the range of precipitation. Increasing peak flows and declining low flows can be adequately explained by urban hydrologic theoryshed. which focuses on the effects of urban impervious surfaces upon direct runoff and infiltration. However, a decline of total runoff in dry years can be explained only by taking into account evapotranspiration as well. The concept of advectively assisted urban evapotranspiration, previously discovered by climatologists, is needed to explain such a loss of total runoff. Urban hydrologic theory must take into account vegetation and evapotranspiration, as well as impervious surfaces and their direct runoff, to explain the magnitude of total annual flows and low flows. Urban stormwater management should address the restoration of low flows, as well as the control of floods.     

重庆金佛山岩溶区不同植被条件下土壤-植被系统CO2浓度日变化

对重庆金佛山典型岩溶区林地、裸地表层岩溶生态系统CO2浓度进行短时间尺度变化的野外观测结果表明,林地与裸地不同深处土温变化幅度由地表向土壤深部逐步降低,裸地地表温度和不同深度土温波动幅度均较林地大.林地与裸地各层次土壤CO2浓度变化与土温呈较好的相关关系.林地各层土壤CO2浓度波动微弱,变幅小于裸地.林地与裸地土层中CO2浓度随土层深度增加而增高.植被各层的温度和温度变化幅度从大到小依次为林层、灌层和草层.林层温度最大值滞后于气温约3 h.     

原地异位建堆热脱附技术和设备在石油污染土壤修复中的应用

利用杰瑞环保科技有限公司自主研发生产的原地异位建堆热脱附设备对新疆某地区506 t石油污染土壤进行了修复处理实验,并在此基础上探讨了原地异位建堆热脱附技术在石油污染土壤修复领域应用的相关技术问题。通过温度场模拟,为设备投入及修复堆体的搭建提供了参考数据;通过项目现场温升曲线,分析了升温效率与物料属性的关系。结果表明,含水率越低的物料升温速率越快。此外,通过对设备投入、石油污染土壤修复效果、修复过程运行能耗等方面进行综合分析,评估了原地异位建堆热脱附技术在石油污染土壤修复领域的有效性和实用性。本研究可为原地异位建堆热脱附技术在石油污染土壤修复领域的工业化应用提供参考。     

Bacterial community structure analyses to assess pollution of water and sediments in the Lake Shkodra/Skadar, Balkan Peninsula

- Goal, Scope, Background. Lake Skadar is the largest lake in Balkan Peninsula, located on the Montenegro-Albanian border. The unique features of the lake and wide range of endemic and rare or endangered plant and animal species resulted in the classification of the Skadar as a wetland site of international significance. In spite of its importance the Lake is influenced by inflowing waters from river Morača and other regional rivers contaminated by the industry, municipal and agricultural activities in the area. Therefore, the Lake has been subject of various physical, chemical, biological and toxicological examinations. However, community-level analyses are most relevant to assess the effect of stressors on aquatic ecosystems. In the present study bacterial community structure among differently polluted sites of the lake was compared by genetic fingerprinting technique. Methods Water and sediment samples were collected from five differently polluted sampling sites on the Lake Skadar in spring and autumn of the same year. The bacterial community structure in the samples was characterized and compared by temporal temperature gel electrophoresis (TTGE) analysis of polymerase chain reaction-amplified bacterial 16S rRNA genes. Results and Discussion The TTGE analysis resulted in many distinguishable and reproducible band patterns, allowing reliable comparison of bacterial communities among sampling sites. Results on the bacterial community structure revealed that three of the selected locations can be considered as sites that have not shown any pollution degradation determined by our method, due to similar structure of bacterial community in the sediment samples. On the other hand, significant shifts in bacterial community structure in the mouth of the river Morača and Plavnica were shown. Since the results coincide with some of the bioassays and chemical analysis performed previously, the changes in bacterial community structure are explained as an effect of antropogenic pollution on the lake ecosystem by waters of river Morača and stream Plavnica. Conclusion The TTGE has proven to be an efficient and reliable method to monitor bacterial dynamics and community shifts in aquatic environment, especially in the sediments. Within the variety of environmental quality assessments the use of TTGE analyses of bacterial community is strongly recommended, particularly as an initial investigation. However, in any conclusion on the state of the environment, the TTGE results should be combined to some other biological, chemical and hydrological data. Recommendation and Outlook Since prokaryotes are a crucial group of organisms in the biosphere, the ecosystem function studies are largely based on bacterial communities. Therefore, bacterial community structure analysis should be a part of an integrated weight of evidence approach in pollution assessment. In case of Triad approach, consisting of chemical analyses, bioassays, and community studies in the field, the TTGE bacterial community structure analyses should be placed in the later Triad leg. In comparison to other community studies, based on various biotic indices, the TTGE bacterial community analysis has proven to be very sensitive, reliable and less time consuming.     

火灾高温下CFRP加固钢筋混凝土梁温度场分析

综合国外CFRP加固混凝土结构抗火试验相关研究,总结了CFRP的高温热工性能参数。用ANSYS软件对火灾高温下不同情况(无防火保护层和有防火保护层)和不同工况(防火涂料涂抹形式)下CFRP加固后的钢筋混凝土梁进行了温度场数值模拟研究。结果表明,防火涂料厚40 mm时,梁耐火极限可达2.5小时以上,且底面和两侧面全面涂抹防火涂料的防火效果最好。本文研究有助于进一步深入认识CFRP加固钢筋混凝土结构在高温下的力学性能和耐火极限,且对CFRP加固后的结构防火设计具有一定的指导意义。     

利用废弃菜籽油制备炭黑-基于气溶胶气相化学沉积法

利用气溶胶化学气相沉积的方式转化废弃菜籽油制备炭黑。以氮气为载气,将液体废油预先转化成气溶胶颗粒输送至高温管式炉,在 800 ℃ 的条件下进行热分解,形成基于废油的炭黑。产物的形貌、组分和结构采用光学显微镜,拉曼光谱, SEM 和 XPS 等方式进行表征。结果显示,炭黑表面呈阶梯片状叠加结构,而拉曼谱上出现强烈的 D 峰、G 峰及 G' 峰（其中 ID/IG=1.09 ）。根据能谱 C1S 峰显示,炭黑表面化学键主要由 sp2 CC,sp3 C—C,C—OH 和 OC—O— 组成,其中 sp2 占据 88.5%。对比分析原始单晶硅基和负载炭黑表面的润湿性,显示负载炭黑后的硅表面疏水性大幅度提高,与水的接触角从 66.4°增长到 141°,呈现超级疏水性;而油在硅基和炭黑表面的接触角分别为 21.2°和<4°。     

Double Green Process: a low environmental impact method for recycling of CdTe,a-Si and CIS/CIGS thin-film photovoltaic modules

On the basis of the method for managing the end of life of CdTe photovoltaic panels previously proposed by the authors, a new method for the recycling of all types of thin-film panels (CdTe, a-Si and CIS/CIGS) has been developed and optimised under a research project founded by Enel Foundation and CRUI Foundation. The DGP process has been developed through a feasibility study carried out from three points of view: technical, environmental and economic. The process is composed by two sub-processes matched to each other, one suitable for CdTe panels (named DGPa) and the other one for a-Si and CIS/CIGS panels (DGPb). The Double Green Panel process is based mainly on mechanical treatments with a minimum use of chemicals and it is characterised by a greater level of automation and a high flexibility in production capacity. The potential environmental impacts of various configurations of the DGP process have been extensively analysed with LCA tool in order to develop an environmentally friendly process. The economic feasibility has been assessed through the Discounted Cash Flow Analysis (DCFA) method. The revenues associated to the recovery of valuable and common materials and the recycling costs have been taken into account.     

两种不同的恒载升温方式下的钢材破坏机理分析

通过对我国建筑结构用钢在拉伸和压缩两种方式下的恒载升温试验,进行了5次受拉试件和2次受压试件的对比研究,根据试验中材料的各自变形规律,对其破坏机理进行了理论分析;从材料屈服的定义出发,给出了恒载升温拉伸试验中的参数(对应温度下的临界荷载水平),并与恒载升温压缩试验中的参数项进行了对比,指出受压构件和受拉构件的高温屈服强度是不同的,因此在钢结构建筑的耐火设计中应分别取不同的安全系数。