Physics Can Help the Economy

¶ … Physics Can Help the Economy of Developing Nations While the demand for Persian Gulf oil continues to increase among the developed nations of the world, many observers caution that water is more important than oil and more attention should be given to this issue immediately, particularly in emerging nations that do not have the infrastructure in place to provide their citizenry with adequate water supplies.

In this regard, treadle irrigation pumps, first used on a commercialized basis in Indonesia in are able to lift up to seven thousand liters of water per hour using the power of the human body, and can be made locally at low cost in small-scale metalworking shops. The acceptance of such devices in Bangladesh where it was first developed in 1984 is spectacular, with more than hundreds of thousands of these simple pumps estimated to be currently in use today.

This paper reviews the peer-reviewed and scholarly literature, as well as organizational and governmental online resources to determine how physics can be used to help developing nations become self-sufficient in food and water production; a recapitulation of the research and salient findings are provided in the summary.

An Examination of How Physics Can Help the Economy of Developing Nations Introduction The use of treadle irrigation pumps is certainly not new, and these devices were in common use through Japan by the 12th century, helping this small country achieve self-sufficiency in agricultural (Grew, 1999). In recent years, the use of the treadle pump by farmers in sub-Saharan Africa and Asia using traditional means of irrigation has resulted in significant production and income increases (Perry, 1996).

Such initiatives are becoming increasingly urgent since many of the developing nations of Africa are experiencing diminishing sources of clean water that will most likely become a prime cause of civil and international instability during the 21st century (Enhancing Support of African Development, 1996). Review What is a treadle pump? The treadle pump is a low-lift, high-capacity, human (usually foot)-powered pump designed to overcome these obstacles.

A treadle pump is capable of lifting five to seven cubic meters of water per hour from wells and boreholes up to seven meters deep as well as from surface water sources such as lakes and rivers. While primitive models were in use in Japan as early as the 12th century, the device in use today was invented in the late 1970s by Gunnar Barnes, a Norwegian engineer working for Lutheran World Federation in Bangladesh.

In the mid-1980s, Daniel Jenkins of the United States Agency for International Development (USAID) developed a PVC version of the treadle pump capable of delivering water under pressure (Perry & Dotson, 2005). In 1987, Appropriate Technology International engineer Carl Bielenberg modified the Jenkins version so that it could be manufactured in the small metal workshops typically found in Africa (Perry & Dotson, 2005). Advantages of treadle irrigation pumps. The treadle pump has two significant advantages over motorized pumps for irrigation of agricultural land of less than one hectare: 1.

The treadle pump is considerably less expensive than motorized pumps. Under typical market conditions, the treadle pump is about 25% of the retail price of motorized pumps of comparable flow rate capacity. 2. The treadle pump costs much less to operate, having no fuel and only limited repair and maintenance costs.

For example, a cost analysis by Hyman (1995), cited in Perry & Dotson) compared treadle pumps and motorized pumps used in Senegal; this analysis showed that a cubic meter of water used in the irrigation of 0.5 hectares had an equivalent cost of $0.08 when supplied by the treadle pump which was just less than half the $0.17 cost for the same amount of water delivered by a motorized pump (Perry & Dotson, 2005). The treadle pump also possesses a number of features which set it apart from other non-motorized irrigation pumps. 1.

Its water lifting capacity of five to seven cubic meters per hour meets the irrigation requirements of most African farmers, the majority of whom cultivate less than one hectare of land. 2. Because the treadle pump employs the user's body weight and leg muscles in a comfortable walking motion, use of the pump can be sustained for extended periods of time without excessive fatigue. The treadle pump is much less tiring than other manual pumps that utilize the upper body and relatively weak arm muscles. 3.

The treadle pump is fabricated entirely from locally-available materials and, as mentioned above, can be manufactured using welding equipment and simple hand tools in the metal workshops commonly found in Africa (Perry & Dotson, 2005). Table 1. Comparison of water-lifting capabilities. Water lifting device Capacity at 4.5 m (l/sec) Initial cost (CFAF) Depth range (m) Rope and bucket 0.3 5 000 0-7 Treadle pump 1.7 63 000 0-7 Motorized pump 2.1 0-7 Perry, 2003. According In India, most of the treadle pump installations are in Uttar Pradesh, Bihar, Orissa and Assam.

Generally, the bamboo versions of treadle pumps can pump water from a depth of about 4.5m-5.75m and the metal version up to 4.5m, treadle pumps have been adopted for application in landholdings of less than one acre (Srinivas & Jalajakshi, 2004). During the early 1990s, the bamboo type of treadle pumps were the most commonly installed.

Though the development of the metallic type of treadle pumps by International Development Enterprises (IDE), started in the 1980s, their actual field installation began only in the mid-1990s; in addition, the introduction of a concrete pump version is a recent one and it has been installed in the field on an experimental basis by IDE in Orissa (Srinivas & Jalajakshi, 2004).

In most cases, a suction pipe of diameter 2.8 cm is used for all types of treadle pumps, similar to that used for hand pumps; then, two cylinders are joined with the suction pipe using a union joint. A sketch of the bamboo and metallic treadle pumps are provided in Figures 1 and 2 below (Srinivas & Jalajakshi, 2004). Plungers (pistons) which are joined to the treadle poles using bolt-nut mechanism do the reciprocatory motion in the cylinders.

All bamboo pumps developed and installed are of 8.75 cm cylinder diameter, with a maximum output of 1.5 liters per second of water lifted from a depth of 5.45-5.75m; the cost of bamboo pumps is less than that of other types. In case of bamboo treadle pump, the treadle poles used for pedaling, support poles, separation poles, are all of bamboo, generally obtained locally (Srinivas & Jalajakshi, 2004).

Cylinders and plungers are made of metal and the washers of made of rubber; the pipe (suction) components are frequently made out of inexpensive and accessible PVC material. According to these authors, "Metallic pumps were developed by the IDE in two sizes 8.75 cm and 12.5 cm cylinder diameter. The 12.5 cm pumps provide an output of 1.5-2 liters per second under suitable conditions" (Srinivas & Jalajakshi, 2004, p. 4273).

The piston stroke is considered to be the more consistent of the designs because the assembly is more rugged; however, the cost of the 12.5 cm metallic treadle pump is the highest compared with other types. With both metallic pumps, the whole assembly of treadle poles used for pedaling, axle pivot and the cylinders come as one unit with a base plate, and is comprised metal which is usually mild steel (Srinivas & Jalajakshi, 2004). Figures 1. And 2. Bamboo and metallic treadle pumps used in India. Source: Srinivas & Jalajakshi, 2004.

The specimen calculations for a treadle pump for one of the bamboo treadle pump tests is provided in Table 3 below. Table 3. Efficiency for Mahangu Nishad's treadle pump.

Efficiency = (Eoutput/Einput) x 100, where Einput = Mass of operator x acceleration due to gravity x strokes/min x stroke length Eoutput = Discharge of water x acceleration due to gravity x total head Einput = 49.5 (kg) x 9.8 (m/sec2) x 87 (strokes/min) x .145 (meter) = 6119.54 joules/min Eoutput = 57 (lpm) x 9.8 (m/sec2) x 4.5 (metres) = 2513.70 joules/min Efficiency = 2513.70 joules/min + 6119.54 joules/min = 41 per cent Source: Srinivas & Jalajakshi, 2004, p. 4274. Impact of treadle irrigation pumps.

Treadle pumps help to reduce the amount of time required to irrigate from almost 12 person-hours per day to slightly more than 4 person-hours per day, while simultaneously enabling the typical market gardener to increase garden size by 40%; not surprisingly, then, the treadle pump has had a profound impact on the profitability of agricultural enterprises throughout Africa (Perry & Dotson, 2005).

Further, expanding the surface area that is already under irrigation with the resulting greater yields have enabled Senegalese market gardeners to generate annual net income gains of $850, a return of 750% on the original investment of $100 in the treadle pump (Hyman, 1995 cited in Perry & Dotson). These authors expect comparable results from similar initiatives in Mali, where ATI began treadle pump commercialization efforts in May 1995 (Perry & Dotson, 2005).

International Development Enterprises (IDE) began distributing treadle pumps throughout Bangladesh in 1981; today, this initiative also includes India, Nepal, Myanmar and Vietnam; all of these projects have enjoyed encouraging results (Perry & Dotson, 2005). Under favorable market conditions of extensive shallow water tables and high population densities, the treadle pump has been adopted by over a million small farmers who produce mostly irrigated cereal crops; likewise, farmers in Bangladesh have increased annual gross incomes by approximately $100 according to a recent IDE publication (Perry & Dotson, 2005).

A study by the Horticultural Export Development Club indicates that several horticultural products being grown in Malawi are in high demand in European markets, particularly Germany, the United Kingdom, France and the Netherlands. These commodities include okra, beans, managementout, chilies, babycorn, sweet corn, asparagus, garlic, courgettes, aubergines (eggplant), sweet pepper, ginger, cherry tomato and mixed herbs; however, the production level of fruits and vegetables remains insufficient to meet domestic needs.

The use of treadle irrigation pumps by Malawi farmers, though, has shown enormous promise by increasing the crop yields and profitability (Mataya & Tsonga, 1999). According to a study by Mataya and Tsonga (1999), a large percentage of the vegetables grown in Malawi are cultivated in wetlands or riverbeds called "dambos"; the introduction of simple as well as more sophisticated irrigation techniques is one way to expand the production base of these commodities. Table 2 below shows the respective performance of.