VITA - Volunteers in Technical Assistance

Glucose From Cassava Starch - 1/01/1990

The product is clear, colorless, glucose syrup, extracted from dried cassava starch or cassava chips. It is sold in drums or tank wagons.

Glucose, also called dextrose, was first manufactured in France early in the 19th century as a sweetener to replace sucrose (table sugar) which had become scarce in wartime. The variety of its uses has since grown enormously. Today, glucose is valued in almost all industrial countries for its unique properties. In candies (sweets) and preserves it provides "body" (desired density and flow characteristics) and controls crystallization. In canning, it provides body to the syrup without too much sweetness.

Understanding Glass Recycling - 1/01/1986

This paper briefly describes the production of glass and its properties, and gives some methods for recycling it. The uses of glass are not limited to these examples and there may indeed be far more inventive ways to reuse glass than are cited here. It is important to remember that any effort to recycle glass must be geared to the demand for either the glass itself or objects made from it. Because of this, it is critical to work at identifying potential markets.

Glass Containers (Batch Process) - 1/01/1991

There are many processes by which the hot, viscous glass can be formed into the desired shapes. Bottles are made by blowing a thick bubble of glass into a mold to give it the desired external shape and to form such features as screw threads or emblems. Such articles as dishes and electrical insulators can also be made by forcing hot, soft glass into a die cavity. This can be done manually or with a machine. Even sheet glass can be made in moderate quantities by flattening molten glass with a water- cooled iron roller. However, making high quality window glass in large quantities requires an investment that is beyond the scope of this paper.

This profile describes small batch production plants with a work force of 10 to 50 people that produce 500 to 25,000 containers a day. The two kinds of batch process are pot process and day-tank process. In the pot process, the glass is produced in refractory clay "pots" that hold 25 to 1,500 kg of raw materials. A circle of 6 to 24 pots is arranged just inside the walls of a large circular furnace. This semi-continuous process can produce about 500 or more bottles a day.

Understanding Evaporative Cooling - 1/01/1985

This paper provides an introduction to the process of evaporative cooling. In addition, the natural limitations and problems associated with this process, along with some practical applications of evaporative cooling are examined.

Guidelines For Planning - 1/01/1985

The purpose of this manual is to help development workers and others to become aware of the environmental factors that should be considered in planning small-scale energy projects that are environmentally sound and therefore more likely to be sustained.

Environmentally sound planning includes the physical environmental factors as well as the socioeconomic and cultural factors. This approach helps assure the protection of the renewable natural resources that supply most of the energy used in the Third World.

Understanding Energy Storage Methods - 1/01/1985

Energy storage capability is essential if the maximum economic advantage is to be gained from small power plants. Unless the power plant is operated at full load on a continual basis, there will be periods when there is a lower load demand upon the plant. As a result of this lower demand, excess energy will be generated by the plant. The use of an energy storage system will allow for the recapture of this surplus energy and its later use during periods of high demand.

This paper presents a critical review of the technical features, state of development, and economics of various energy storage systems and their compatibility with small power plants. The small power plants examined here have generation capacities within a range of 1 to 50 kilowatts (kW) and consist of systems such as windmills and small-scale hydropower.

Earth Moving Devices For Irrigation And Road-Building - 1/01/1987

Moving soil for irrigation and road-building is important to good farming. Careful preparation of land for irrigation and good water usage saves water, labor, and soil, and improves crop yields. Improved roads make communication easier between farmers, their suppliers, and their markets.

Although modern heavy equipment is often sought for such work, it is not necessary. Land can be prepared effectively with small equipment that can be made by farmers or small manufacturers and can be pulled by animals or farm tractors. Descriptions of yokes and harnesses are given in Animal Traction, by Peter R. Watson, published by Peace Corps and TransCentury Corporation (1981).

Women's Broadcloth Dresses - 1/01/1987

This Profile describes a plant operating with one shift and manufacturing 72,000 women's dresses a year (1,440/week, 288/day). It also describes a larger plant running a single shift and producing 104,000 dresses a year.

Other similar products such as women's and girls' blouses, cotton skirts, and school uniforms can also be made at this facility. Therefore it is important to have a designer/pattern-maker readily available to produce properly fitted items as may be requested by the customer.

Dimension Hardwood - 1/01/1989

The product is hardwood, kiln dried and machined to dimensions required by customers. Products of the mill may include cut-to-size rectangular pieces, edge-glued panels, moldings, turnings, cabinet parts, stair treads and risers, and shaped pieces, as well as by-products useful as fuel. Most customers are manufacturers of furniture, cabinetwork, doorframes and windowframes, toys, boxes, and decorative or display items. Products vary greatly among mills; some mills may produce finished articles for the consumer market.

Understanding Passive Cooling Systems - 1/01/1986

Passive cooling systems use simple, low-cost techniques to provide summer comfort in warm climates for people and animals in buildings. Such systems can also be used to keep food, liquids, and other materials at temperatures that will prevent spoiling or other deterioration.

Passive cooling is far less costly to operate than active cooling systems such as air conditioning which typically use vapor-compression or absorption refrigeration and require complex electromechanical equipment and a power supply. Passive cooling methods use simple mechanisms and require no input of electrical energy or conventional fuels.

The need for passive solar cooling, and the selection of appropriate methods for achieving it, depend primarily on the climatic conditions of a region, the cultural context, and the materials available locally.