Moisture Sorption Characteristics of Microbially Produced Polysaccharide and Polyvinyl Alcohol Blends

Moisture sorption characteristics of microbial polysaccharide (Ps.C101) from Pseudomonas caryophilli and polyvinyl alcohol (PVA) blends have been carried out at 27°C for water activity from 0.1 to 0.9. The sorption data was used to fit six different sorption isotherm models proposed in literature. The model constants were determined by linear fitting of the sorption equations. The ranges of applicability of water activity for isotherm models reported in this paper lie in between 0.1 and 0.4 for Brunaur–Emmet–Teller (BET) model (monolayer), and in between 0.2 and 0.9 for other models. The value of the coefficient of determination (R² = 0.97 ± 0.02) confirms the applicability of the equations studied.     

An Overview on the Mechanical Behaviour of Biodegradable Agricultural Films

The mechanical behavior of various types of biodegradable materials depends, mainly, on their chemical composition and the application conditions. Various additives are added into the bioblends to improve their properties, which sometimes even reach the levels of the conventional plastics. It is well known that the environmental conditions during production, storage, and usage of these materials influence their mechanical properties. Ageing during the useful lifetime also causes great losses in the elongation. In the present paper, the overall mechanical behavior of biodegradable films, which may be considered suitable for agricultural applications, but also of partially biodegradable films, is reviewed and analyzed. Selected critical mechanical properties of films before their exposure to biodegradation are investigated and compared against those of conventional agricultural films.     

Biodegradable Soy-Based Plastics: Opportunities and Challenges

Today's plastics are designed with little consideration for their ultimate disposability or the effect of the resources (feedstocks) used in making them. This has resulted in mounting worldwide concerns over the environmental consequences of such materials when they enter the mainstream after their intended uses. This led to the concept of designing and engineering new biodegradable materials–materials that have the performance characteristics of today's materials but that undergo biodegradation along with other organic waste to soil humic materials. Hence, the production of biodegradable materials from annually renewable agricultural feedstocks has attracted attention in recent years. Agricultural materials such as starches and proteins are biodegradable and environmentally friendly. Soybean is a good candidate for manufacturing a large number of chemicals, including biodegradable plastics, as it is abundantly available and cheap. Soy protein concentrate, isolate, or flakes could be compounded with synthetic biodegradable plastics such as polycaprolactone or poly (lactic acid) to make molded products or edible films or shopping bags and make the environment cleaner and greener.     

溶胶-凝胶工艺制备掺铅TiO_2纳米薄膜及其光催化性能的研究

通过ｓｏｌ－ｇｅｌ工艺在玻璃表面制得了均匀透明的掺铅和未掺铅ＴｉＯ２纳米薄膜；在宏观上，膜层表面光滑平整；在微观上，ＴｉＯ２薄膜由ＴｉＯ２球形颗粒组成，其颗粒大小在５０～１５０ｎｍ范围内。掺铅ＴｉＯ２镀膜玻璃在紫外光附近的透光率明显小于未掺铅ＴｉＯ２镀膜玻璃的透光率，这说明掺铅ＴｉＯ２镀膜玻璃对紫外光具有明显的吸收。敌敌畏水溶液的光摧化降解实验表明，掺铅ＴｉＯ２镀膜玻璃对有机磷农药的光解率明显高于未掺铅ＴｉＯ２镀膜玻璃的光解率。这为进一步提高ＴｉＯ２的光催化效率开辟了新的途径。     

薄壁管螺旋槽的旋压工艺研究

介绍了薄壁管螺旋槽旋压时的测力装置和各工艺参数对旋压力的影响,可为设计旋压机床、编制旋压工艺,设计工夹具提供理论依据。     

光电催化降解2,4-二氯苯酚的研究

采用Sol-Gel法制备了纳米TiO2／导电玻璃薄膜电极，应用XRD表征了TiO2薄膜的物相和粒度，以上述电极为工作电极和光催化剂，研究了2，4－二氯苯酚溶液的光催化和光电催化降解行为，结果表明，外加阳极偏压为0．7V，时间100min时，光电催化降解率为85％，高出光催化降解25％，2，4－DCP初始浓度（C0）与反应速率（r0)的关系符合Langmuir-Hinshelwood方程，当C0≤0．50mmol.L^-1时，光电催化降解速率可用一级动力学模式来描述。     

深孔薄壁锥形件冷加工工艺研究

通过对锥形件产品的研制 ,论证了采用复合挤压、变薄拉伸和扩锥挤压相结合的工艺方法是加工深孔薄壁锥形件的可靠工艺方法 ,得出了变薄拉伸加工中加工率不应处于临界加工率状态的结论。     

城市污水管网地理信息系统设计

以地理信息系统(GIS)为技术支持。结合污水管网管理的实际需求。在VB环境下利用GeoMap控件进行二次开发，建立了污水管网地理信息系统。该系统充分发挥了GIS对空间、属性数据的编辑、管理、显示和查询的功能，并实现了在GIS环境下对污水管网流量的计算和水质的分析功能。     

纳米TiO2薄膜在不同基质表面的负载及光催化性能

以釉面陶瓷和普通钠钙玻璃为载体,用溶胶凝胶法在其表面进行了纳米TiO2薄膜的负载.采用X射线衍射法(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)对薄膜进行了表征与分析.结果表明,TiO2为完全的锐钛矿型,平均粒径约为15nm;TiO2薄膜在2种载体上分布均匀,膜厚约为300nm;TiO2薄膜在釉面陶瓷表面呈连续分布,而在玻璃表面上出现了破裂现象;2种载体中的一些基质离子在TiO2薄膜均有渗透.光降解实验表明,2种载体上的TiO2薄膜对亚甲基蓝的降解均符合一级反应动力学.TiO2/釉面陶瓷催化活性大于TiO2/玻璃,该薄膜对实际生产多菌灵废水具有催化降解作用.2种载体上的TiO2薄膜重复使用20次,对亚甲基蓝的去除率降低约2%.     

FLOOD INUNDATION IN THE SOUTHEASTERN UNITED STATES FROM AIRCRAFT AND SATELLITE IMAGERY1

ABSTRACT: Panchromatic black and white, color, and color infrared photographs and thermal infrared imagery are compared for a capability to show flood boundaries. In open agricultural and urban areas, these boundaries are easily delineated on all types of am. Boundaries are more difficult to see in wooded areas. In March, hardwood trees are dormant, but black and white photographs and color photographs show only the tops of these trees. Color infrared photographs in January and March have a distinctive color or tone in inundated woods; the limit of this tone is the flood boundary. Daytime thermal infrared imagery in March shows that inundated woods are cooler than dry land but warmer than open water. After about April 1, both color infrared photography and thermal infrared imagery show only the top of the tree canopy and do not reflect underlying flood water. Inundated areas can be delineated easily on ERTS satellite imagery from December through March. On imagery from May 4–5, 1973, however, most inundation boundaries had to be drawn as dashed lines; the tree canopy obscures flood waters in wooded areas. Despite this problem, the results of mapping flood boundaries on May imagery are believed to be reasonable for the scale of the imagery.