逆流喷雾式饱和器内湿化过程的实验研究

对逆流喷雾式饱和器内部空气的湿化过程进行实验研究,实验中不仅测量了饱和器进出口湿空气的相对湿度、温度和水的温度,而且也测量了饱和器内部几个高度截面上湿空气的相对湿度和气相、液相的温度。根据实验测量的湿空气的相对湿度和温度,计算出了饱和器内湿空气的含湿量和测量高度间湿空气的加湿量。由实验结果可见,随水气质量比的增大,饱和器出口湿空气的温度和温升也相应增大。湿空气的含湿量和水的蒸发量、出口温度随进口水温升高、水气质量比增大而增大。在所有实验工况下,饱和器出口湿空气接近或达到饱和。随空气速度增大水滴逃逸量增大。总体上饱和器内部下部主要是加湿进口空气,上部是加湿和加热空气。

新疆现代与历史暖湿化过程及对生态环境影响

一、项目背景 20世纪、50年代到80年代新疆气候暖干过程与80年代至今的暖湿过程，气候与生态环境的反映非常明显。但这种突变过程的深度、发展周期和对环境的影响都不清楚。本项目根据历史的记载、树木年轮记录以及实际观测资料的实验与分析，有论有据地提出新疆的历史气候变化序列，为研究气候与生态环境变化之间的关系提供科学、系统、定量的基础数据。

红山窑膨胀红砂岩湿化特性试验研究

针对红山窑膨胀红砂岩具有微膨胀、易软化、易风化的特点,采用扫描电子显微镜、X射线衍射仪、MTS815.03岩石力学刚性电液伺服试验机等先进的设备为测试手段,对3种不同风化程度的膨胀红砂岩湿化过程进行观察和机理分析,从试验和机理两方面探讨膨胀红砂岩的湿化性,从而进一步阐明红砂岩膨胀性、裂隙化具有本质的区别。试验结果表明:(1)中风化红砂岩干燥时抗压强度为5.85MPa,饱和试样为0.20MPa,岩石本身强度随吸水率增加而明显下降,具有强烈的软化作用;(2)膨胀红砂岩的湿化性随胶结系数的减小而愈加强烈,与红砂岩风化程度(埋深)无关。这些研究成果对红山窑水利枢纽工程红砂岩地基开挖易裂以及边坡表层溜坍预治具有较大的指导意义。

膨胀岩的湿化特性及其对堑坡浅层溜坍的影响

通过６种膨胀岩的湿化过程观察和机理研究，从试验和理论两方面探讨了膨胀岩的湿化性，并与膨胀性和裂隙性进行了区别。湿化性对堑坡稳定性，尤其是表层溜坍的影响，主要体现在ｃ，φ值随吸水率的增加而降低上。理论计算的溜坍体厚度与锥贯入试验确定的强湿化层厚度相同，说明湿化性是造成堑坡溜坍的主要原因。

Geomorphic-centered Classification of Wetlands on the Qinghai-Tibet Plateau, Western China

In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful managementto avoid degradation.

Landscape Pattern Evolution Processes of Alpine Wetlands and Their Driving Factors in the Zoige Plateau of China

Zoige Plateau wetlands are located in the northeastern corner of the Qinghai-Tibet Plateau.The landscape pattern evolution processes in the Zoige Plateau and their driving factors were identified by analyzing the dynamic changes in landscape modification and conversion and their dynamic rates of alpine wetlands over the past four decades.The results showed that the landscape conversion between wetlands and non-wetlands mainly occurred during the period from 1966 to 1986.The marsh wetland area converted from lake and river wetlands was larger because of swamping compared to other wetland landscapes.Meanwhile,the larger area of marsh wetlands was also converted to lake wetlands more than other types of wetlands.The modification processes mainly occurred among natural wetland landscapes in the first three periods.Obvious conversions were observed between wetland and nonwetland landscapes(i.e.,forestland,grassland,and other landscapes) in the Zoige Plateau.These natural wetland landscapes such as river,lake and marsh wetlands showed a net loss over the past four decades,whereas artificial wetland landscapes(i.e.,paddy field and reservoir and pond wetlands) showed a net decrease.The annual dynamic rate of the whole wetland landscape was 0.72%,in which the annual dynamic rate of river wetlands was the highest,followed by lake wetlands,while marsh wetlands had the lowest dynamic rate.The integrated landscape dynamic rate showed a decreasing trend in the first three periods.The changes in wetland landscape patterns were comprehensively controlled by natural factors and human activities,especially human activities play an important role in changing wetland landscape patterns.

Process simulation and optimization of flow field in wet electrostatic precipitator

To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.

Comparison of deep desulfurization methods in alumina production process

Several methods of deep desulfurization in alumina production process were studied, and the costs of these methods were compared. It is found that most of the S2- in sodium aluminate solution can be removed by adding sodium nitrate or hydrogen peroxide in digestion process, and in this way the effect of S2- on alumina product quality is eliminated. However, the removal efficiency of 2?32OS in sodium aluminate solution is very low by this method. Both S2- and 2?32OS in sodium aluminate solution can be removed completely by wet oxidation method in digestion process. The cost of desulfurization by wet oxidation is lower than by adding sodium nitrate or hydrogen peroxide. The results of this research reveal that wet oxidation is an economical and feasible method for the removal of sulfur in alumina production process to improve alumina quality, and provide valuable guidelines for alumina production by high-sulfur bauxite.

Removing chlorine of CuCl residue from zinc hydrometallurgy by microwave roasting

Most Zn hydrometallurgy factories adopt Cu2SO4 as a dechlorination reagent from zinc solution nowadays, thus much CuCl residue is produced. The existing process of treating this residue is washing with water or sodium carbonate solution, which would cause a lot of troubles to water treatment and waste discharge. A method of microwave roasting was adopted for dechlorination of CuCl residue. A 1.5 kW microwave roasting equipment with dust collection and tail gas adsorption systems was set up and applied during the experiment. By investigating the effect of temperature, heat preservation time, moisture content of raw material and grain size of samples on the dechlorination, the optimal experimental condition is obtained. When the samples with 2% moisture and <150 μm grain size are microwave roasted at 400 °C for 2 h, the Cl content turns from 14.27% to 1.35% and the dechlorination rate is as high as 90%, while that with conventional heating is only 60%-80%. The phase change of the roasting process investigated with X-ray diffraction verifies that CuCl in CuCl residue is removed by being transformed into CuO.

Extending the Use of Hothouses through Heating with Residual Agricultural Biomass

The paper presents a study on increasing energy independence of a 200 m2 horticultural hothouse, by means of heating it with thermal energy from a TLUD （top-lit-up-draft） gasification procedure of local residual agricultural biomass, chopped at 10-50 mm and dried at 10%-15% RH （relative humidity）. It produces an average of 14% higt quality biochar. Hot-air heating system and forced circulation are equipped with two GAZMER 40/150G energetic modules, which are rechargeable, simple, safe, efficient and environmentally friendly. They can gasify chopped or pelletised biomass. To study the microclimate evolution, it was used a complex numerical model for a 200 m2 hothouse for growing vegetables. Simulated experiments were carried out for frosty days and, estimated, for the whole warming period. Each year 13.44 t of biomass are consumed, resulting 1.78 t ofbiochar which, when introduced in soil, produces a -6.2 t/year negative balance of CO2.

Investigation in Mathematical Models of Chloride Diffusion Coefficient in Concrete Exposed to Marine Environment

Degradation of RC （reinforced concrete） in maritime structures has become a worldwide problem due to its excessive costs of maintenance, repair and replacement in addition to its environmental impacts and safety issues. Degradation of both concrete and steel which is the main reason of reduction in the service life of RC structures strongly depends on the diffusion process of moisture and aggressive species. In this paper, the major and popular mathematical models of diffusion process in concrete are surveyed and investigated. Predominantly in these models, the coefficient of chloride diffusion into the concrete is assumed to be constant. Whereas, experimental records indicate that diffusion coefficient is a function of time. Subsequently, data analysis and comparisons between the existing analytical models for predicting the diffusion coefficient with the existing experimental database are carried out in this study. Clearly, these comparisons reveal that there are gaps between the existing mathematical models and previously recorded experimental results. Perhaps, these gaps may be interpreted as influence of the other affecting parameters on the diffusion coefficient such as temperature, aggregate size and relative humidity in addition to the water cement ratio. Accordingly, the existing mathematical models are not adequate enough to predict the diffusion coefficient precisely and further studies need to be performed.