大城市远郊区农村建设与乡村旅游发展——以上海金山漕泾镇水库村“休闲水庄“规划为例

针对当前大城市郊区农村建设中的问题,以上海金山漕泾镇水库村“休闲水庄”的规划为例,以乡村旅游为突破点,将当地的生态资源和农产品进行整合,提出了“休闲水庄”的构想,带动远郊区农村建设,增加农民收入。通过与乡村旅游的结合,传统的第一产业转化为以旅游和服务为主导的、高附加值的第三产业。乡村旅游发展为社会主义新农村建设提供了一种思路。     

MELTING OF ICE AROUND A HORIZONTAL ISOTHERMAL CYLINDRICAL HEAT SOURCE

Processes during melting from a horizontal cylindrical heat source of uniform surface temperature embedded in ice have been studied experimentally. The volume of the melt and its shape were photographed at different times for various constant temperatures of the heat source. At early times and under all conditions, the melt occupied a cylindrical annulus. At later times free convective motion caused pear-shaped melt contours which pointed downward when the temperatures of the heat source were below 7°C and upward when the temperatures were above 8°C. Instabilities in cellular natural convection motion resulted in waviness of the interface. The location and magnitude of these ripples were found to depend on the temperature of the heat source and the melt layer thickness. Shadowgraph techniques were used to determine local heat transfer coefficients at the heat source surface.     

Quantitative Determination of Ascorbic Acid in Potatoes and Potato Products by High Performance Liquid Chromatography

A simple, rapid and accurate method for the quantitative determination of ascorbic acid in potatoes and potato products has been developed. The system is based on the reverse-phase, ion-pairing concept of high-performance liquid chromatography. Sample preparation is minimal and involves a one-step extraction followed by filtration and/or centrifugation. Recoveries were near the 100% level. As low as 0.02 mcg ascorbic acid could be determined.     

Simultaneous Determination of Thiamin and Riboflavin in Selected Foods by High-Performance Liquid Chromatography

A high-performance liquid chromatographic (HPLC) system that makes it possible to accurately and simultaneously quantitate low levels of riboflavin and thiamin (thiochrome) from single extracts following oxidation and sample preconcentration steps is described. Several food matrices were analyzed and the results compared to the AOAC method now in use. Within the range of standard deviations, both methods gave comparable values. This method is rapid, accurate, sensitive and economical, making it attractive to those who require routine analysis of thiamin and riboflavin.     

Retention of Some Water-Soluble Vitamins During Home Preparation of Commercially Frozen Potato Products

The retention of several water-soluble vitamins during home preparation of commercially frozen potato products was investigated. Retention values were lowest with ascorbic acid and folic acid. Depending on the potato product and the method of home preparation these values ranged from 53–91%, and from 14–75% for ascrobic acid and folic acid, respectively. Thiamin retention values varied between total retention in pan-fried hashbrowns to 59% in pan-fried shoestring French fries. Niacin values were not affected by home preparation whereas in the case of vitamin B₆ values ranged from total retention to 79% retention.     

Vitamin C Retention of Potato Fries Blanched in Water

Vitamin C retention was determined microfluorometrically for French fries heated in water. Vitamin C retention for 1.3 cm (½ in.) water blanched French fries ranged from 83.2–54.1%. The French fry blanch times were 5, 10 and 15 min at 66°C, 77°C and 88°C. The apparent Ea was 4.0 Kcal/mole.     

Fuzzy clustering of mechanisms

During the course of development of Mechanical Engineering, a large number of mechanisms (that is, linkages to perform various types of tasks) have been conceived and developed. Quite a few atlases and catalogues were prepared by the designers of machines and mechanical systems. However, often it is felt that a clustering technique for handling the list of large number of mechanisms can be very useful, if it is developed based on a scientific principle. In this paper, it has been shown that the concept of fuzzy sets can be conveniently used for this purpose, if an adequate number of properly chosen attributes (also called characteristics) are identified. Using two clustering techniques, the mechanisms have been classified in the present work and in future, it may be extended to develop an expert system, which can automate type synthesis phase of mechanical design. To the best of the authors?? knowledge, this type of clustering of mechanisms has not been attempted before. Thus, this is the first attempt to cluster the mechanisms based on some quantitative measures. It may help the engineers to carry out type synthesis of the mechanisms.     

Changes in the Vitamin B-6 Content in Potatoes During Storage

The nature of the repeatedly reported increase of vitamin B-6 in Russet Burbank potatoes stored for 30 days and 9 months was investigated. Potatoes contained pyridoxine, pyridoxamine, pyridoxal phosphate, and a pyridoxine glucoside. While pyridoxamine and pyridoxal phosphate concentrations remained unchanged, there was a sharp increase in pyridoxine glucoside during storage indicating a possible synthesis of vitamin B-6 during storage. In general, good agreement existed between the data generated by microbial analysis and those obtained by the HPLC method.