Scenario-Based Robustness Analysis of Optimized I.D.E.-Style Treadle Pump Designs

2016 ◽  
Author(s):  
Christopher McComb ◽  
Nathan G. Johnson ◽  
Brandon T. Gorman
Keyword(s):  
Developing Countries ◽  
Service Providers ◽  
Operating Cost ◽  
Robustness Analysis ◽  
Development Aid ◽  
Low Flow ◽  
Entrepreneurial Activity ◽  
Small Scale ◽  
Pareto Optimal ◽  
Flow Rates

Poverty affects hundreds of millions of people globally. Market-based strategies can help alleviate poverty in developing countries by encouraging entrepreneurial activity and have the potential to be more effective than traditional approaches, such as development aid from countries or non-governmental organizations. Development organizations often target the agricultural sector because of the prevalence of subsistence and small-scale farming, particularly in rural regions of developing countries. Improving the reliability of irrigation techniques can help farmers expand out of primarily subsistence farming and begin to sell a portion of their crop, thus achieving the objectives of market-based poverty alleviation. Human-powered pumps are a popular tool used in irrigation because they require low capital cost and negligible operating cost. Previous work provided a model for finding Pareto-optimal IDE-style treadle pump designs. This work utilizes that model to produce a dense set of Pareto-optimal designs, and then investigates the robustness of the designs by simulating their performance in a variety of modified use scenarios. Our results show that pumps optimized for low flow rates (less than 3.0 L/s) are highly robust, particularly with respect to age-related changes in the operator’s stature or mobility. In addition, these pumps can operate with near-optimal efficiency across a variety of target flow rates and well depths. These pumps are ideal for single family use or for shared use amongst multiple families in a village. Pumps optimized for flow rates greater than 3.0 L/s are less robust with respect to changes of operator stature (experiencing decreases in flow rate of up to 60%) but may be suitable for use on farms or by service providers.

scholarly journals Critical parameters in the production of ceramic pot filters for household water treatment in developing countries

2014 ◽  
Vol 13 (2) ◽  
pp. 587-599 ◽  
Author(s):  
A. I. A. Soppe ◽  
S. G. J. Heijman ◽  
I. Gensburger ◽  
A. Shantz ◽  
D. van Halem ◽  
...  
Keyword(s):  
Developing Countries ◽  
Water Treatment ◽  
Removal Efficiency ◽  
Rice Husk ◽  
Flow Rate ◽  
Critical Parameters ◽  
Small Scale ◽  
Material Strength ◽  
Flow Rates ◽  
Pore Sizes

The need to improve the access to safe water is generally recognized for the benefit of public health in developing countries. This study's objective was to identify critical parameters which are essential for improving the performance of ceramic pot filters (CPFs) as a point-of-use water treatment system. Defining critical production parameters was also relevant to confirm that CPFs with high-flow rates may have the same disinfection capacity as pots with normal flow rates. A pilot unit was built in Cambodia to produce CPFs under controlled and constant conditions. Pots were manufactured from a mixture of clay, laterite and rice husk in a small-scale, gas-fired, temperature-controlled kiln and tested for flow rate, removal efficiency of bacteria and material strength. Flow rate can be increased by increasing pore sizes and by increasing porosity. Pore sizes were increased by using larger rice husk particles and porosity was increased with larger proportions of rice husk in the clay mixture. The main conclusions: larger pore size decreases the removal efficiency of bacteria; higher porosity does not affect the removal efficiency of bacteria, but does influence the strength of pots; flow rates of CPFs can be raised to 10–20 L/hour without a significant decrease in bacterial removal efficiency.

Entrepreneurship and Sustainable Tourism: The Houseboats of Kerala

2002 ◽  
Vol 4 (1) ◽  
pp. 7-20 ◽  
Author(s):  
Jithendran Kokkranikal ◽  
Alison Morrison
Keyword(s):  
Developing Countries ◽  
Sustainable Tourism ◽  
Local Communities ◽  
Entrepreneurial Activity ◽  
Social Benefits ◽  
Small Scale ◽  
Descriptive Case Study ◽  
Self Employment ◽  
Tourism Product

Within developing countries it has been identified that one means of achieving sustainable tourism is through the effective engagement of local communities. In particular, this involves the encouragement of indigenous entrepreneurship, often in the forms of self-employment and small-scale enterprises. The aim is to maximise potential economic and social benefits of tourism development within the host destinations. This paper provides a conceptual framework and descriptive case study within which to analyse an example of indigenous entrepreneurship as evidence in the operators of a houseboat tourism product in the State of Kerala, India. Conclusions are drawn relative to the sustainability of both the product and indigenous entrepreneurial activity.

An Experimental Investigation of a Temperature Controlled Vapor Supply System

2013 ◽  
Author(s):  
Robert G. Ryan ◽  
Jeffrey Bunting
Keyword(s):  
Constant Pressure ◽  
Heat Transfer Process ◽  
Supply System ◽  
Low Flow ◽  
Small Scale ◽  
Mechanical Pressure ◽  
Vapor Source ◽  
Flow Rates ◽  
Supply Tank ◽  
Temperature Levels

A variety of applications require a constant pressure vapor supply for processes such as purging fluid systems. A typical design would use a high pressure tank of gas (e.g. helium) along with a mechanical pressure regulator to deliver a constant pressure flow. An alternative concept for the vapor source is to use a tank containing a saturated liquid-vapor mixture. As the vapor is drawn off of the top of the tank, the temperature of the mixture is controlled to maintain the desired vapor delivery pressure. The potential advantage of this approach is that the vapor supply system can be designed to be lighter, more compact, and safer. An experiment was designed to test the practicality of this concept in a small scale system. Carbon dioxide was chosen for the saturated mixture due to its availability, safety, and desirable operating pressures near ambient temperature levels. The apparatus was designed to allow for the measurement of relevant temperatures and pressures over a range of vapor delivery flow rates. Temperature control of the supply tank was accomplished by submergence in an ice bath. The experimental results confirm that this type of system can produce a well regulated vapor supply at low flow rates, but fails to produce steady pressures at higher delivery flows due to limitations of the heat transfer process in the supply tank.

Optimizing the Design of Unbonded Flexible Pipelines With More Realistic Predictions of pH and H2S Content in the Annulus

2017 ◽  
Author(s):  
Li Ke ◽  
Carol Taravel-Condat ◽  
Jean Kittel ◽  
Rémy Mingant ◽  
Claude Duret-Thual ◽  
...  
Keyword(s):  
Ph Monitoring ◽  
Stationary Phases ◽  
Oil Field ◽  
Low Flow ◽  
Small Scale ◽  
Flow Rates ◽  
Dissolved Iron ◽  
Flexible Pipes ◽  
Steel Grades

Due to its high metallic confinement, the annulus of unbonded flexible pipelines is a specific and mild corrosive medium for carbon steel armour wires. This environment presents high supersaturation levels of dissolved iron, leading to pH values far above thermodynamic equilibrium. Furthermore, the permeation of acidic gases (such as CO2 and H2S) through the polymer pressure sheath occurs at very low flow rates. Since the annulus is supersaturated with dissolved iron, part of the H2S is consumed as it slowly arrives into the annulus. Therefore, the annular medium contains low levels of gas far below those predicted by standard thermodynamic models, and less H2S is available to trigger sour cracking. The recent development of harsher oil field conditions (higher water depths, increased CO2 content, presence of H2S...) induced the need to refine the design of flexible pipes to propose more cost effective solutions. As pH and H2S content are key parameters for the selection of steel grades, taking into account the supersaturation and the H2S consumption in the annulus allows major optimization of flexible pipes by using for instance steel grades with higher strength. Therefore, extensive experimental work was conducted over the past years to better characterize the annulus and predict more realistic pH and H2S levels. In this paper, the following developments are presented: – A kinetic corrosion model named FlexCor was derived from numerous corrosion tests done at various CO2 pressures in confined configuration, with in-situ pH monitoring. These tests were performed over long durations (3 months) in order to capture the effective long term supersaturated pH. The kinetic model is able to simulate the transient and stationary phases of the supersaturated pH evolution up to 45 bara of CO2, providing a good fit with the experimental data. The tests also demonstrated that the annulus environment remains supersaturated even at high CO2 partial pressures. – A methodology taking into account the H2S consumption was developed based on extensive long-term small scale and full scale testing (> 2 years), where low flow rates of H2S were imposed. The experimental results show that H2S consumption is far from negligible, even when the annulus is not fully flooded. This H2S consumption methodology was certified by an Independent Verification Agency and is now being applied on commercial projects.

Numerical Study of Premixed Combustion of Methane Stabilized on Porous Medium

2016 ◽  
Author(s):  
Valerio Giovannoni ◽  
Rajnish N. Sharma ◽  
Robert R. Raine
Keyword(s):  
Porous Medium ◽  
Numerical Study ◽  
Burning Velocity ◽  
Combustion Process ◽  
Heat Losses ◽  
Low Flow ◽  
Small Scale ◽  
High Porosity ◽  
Flow Rates ◽  
Flame Holder

The present study focuses on the numerical analysis of the combustion process occurring in a small scale cylindrical combustion chamber using a commercial computational code. The chosen diameter is 18 mm, being the same as the flat flame regenerative combustor currently under experimental investigation by the author (Giovannoni), and it includes a 10 mm thick porous flame holder and a 1 mm thick stainless steel outer wall. A 17 species and 73 reactions skeletal mechanism related to methane oxidation is employed for the simulations. A parametric study is performed and results in terms of temperature profiles, major species’ concentrations and flow velocities are presented. Results show that the flame holder can considerably affect combustion and heat losses from the combustor. In particular at low flow rates, when the laminar burning velocity is much higher than the flow velocity, heat is lost mainly through the flame holder to the walls and to the surroundings. At high flow rates the flame appears to be slightly lifted from the porous medium and heat is mainly dispersed to the walls. This causes preheating of the mixture upstream of the combustion through axial conduction in the wall, achieving superadiabatic temperature. It is also clear from the simulations that employing a flame holder with low thermal conductivity and high porosity yields benefits in limiting heat losses and in widening flammability limits.

An integrated, small-scale agricultural model to aid developing countries

1984 ◽  
Vol 13 (2) ◽  
pp. 99-103 ◽  
Author(s):  
James A. Tindall ◽  
Laren R. Robison ◽  
N. Paul Johnston ◽  
Von D. Jolley
Keyword(s):  
Developing Countries ◽  
Small Scale

Treatment of Rural Domestic Sewage by Solar Ozonic Ecological Sewage Treatment Plant

2014 ◽  
Vol 955-959 ◽  
pp. 3393-3399 ◽  
Author(s):  
Wei Zheng ◽  
Yan Ming Yang ◽  
Yun Long Li ◽  
Jian Qiu Zheng
Keyword(s):  
Municipal Wastewater ◽  
Operating Cost ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Domestic Sewage ◽  
Design Parameters ◽  
Small Scale ◽  
Municipal Wastewater Treatment ◽  
Average Percentage

The process technique and design parameters of project of Solar Ozonic Ecological Sewage Treatment Plant (short for SOESTP) which consists of anaerobic reactor, horizontal subsurface flow (HSSF) constructed wetlands(CWs) and the combination of solar power and ozone disinfection are described, the paper further examines the removal efficiency for treating rural domestic sewage, running expense and recycling ability of product water. The results show that the average percentage removal values of CODcr，BOD5，SS，TN，NH3-N，TP range from 95.6% to 98.0%, 96.0% to 98.7%, 93.1% to 96.1%, 97.0% to 98.9%, 96.9% to 99.5%, 98.2% to 99.6%, respectively, the reduction of fecal coliform (FC) reaches 99.9%, the effluent quality meets the first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant（GB18918-2002）. The running cost of SOESTP is 0.063yuan/ m3, saves much more than traditional sewage treatment, and the ozone water obtained from the reservoir will be an ideal choice for disinfection .The system has characteristics of easy manipulation, low operating cost, achieving advanced water, energy conservation and environment protection, is thought to be very suitable for use as the promotion of rural small - scale sewage treatment.

scholarly journals How Do Women Overcome Gender Inequality by Forming Small-Scale Cooperatives? The Case of the Agricultural Sector in Uganda

2021 ◽  
Vol 13 (4) ◽  
pp. 1797
Author(s):  
Amber Theeuwen ◽  
Valérie Duplat ◽  
Christopher Wickert ◽  
Brian Tjemkes
Keyword(s):  
Developing Countries ◽  
Gender Equality ◽  
Gender Inequality ◽  
Family Business ◽  
Agricultural Sector ◽  
Economic Benefits ◽  
Policy Implications ◽  
Small Scale ◽  
Business Relationships ◽  
Female Farmers

In Uganda, the agricultural sector contributes substantially to gross domestic product. Although the involvement of Ugandan women in this sector is extensive, female farmers face significant obstacles, caused by gendering that impedes their ability to expand their family business and to generate incomes. Gender refers to social or cultural categories by which women–men relationships are conceived. In this study, we aim to investigate how gendering influences the development of business relationships in the Ugandan agricultural sector. To do so, we employed a qualitative–inductive methodology to collect unique data on the rice and cassava sectors. Our findings reveal at first that, in the agricultural sector in Uganda, inter-organization business relationships (i.e., between non-family actors) are mostly developed by and between men, whereas intra-organization business relationships with family members are mostly developed by women. We learn that gendering impedes women from developing inter-organization business relationships. Impediments for female farmers include their restricted mobility, the lack of trust by men, their limited freedom in communication, household duties, and responsibilities for farming activities up until sales. Our findings also reveal that these impediments to developing inter-organization business relationships prevent female farmers from being empowered and from attainting economic benefits for the family business. In this context, the results of our study show that grouping in small-scale cooperatives offers female farmers an opportunity to overcome gender inequality and to become economically emancipated. Thanks to these cooperatives, women can develop inter-organization relationships with men and other women and gain easier access to financial resources. Small-scale cooperatives can alter gendering in the long run, in favor of more gender equality and less marginalization of women. Our study responds to calls for more research on the informal economy in developing countries and brings further understanding to the effect of gendering in the Ugandan agricultural sector. We propose a theoretical framework with eight propositions bridging gendering, business relationship development, and empowerment and economic benefits. Our framework serves as a springboard for policy implications aimed at fostering gender equality in informal sectors in developing countries.

scholarly journals Comparison of LPWAN Technologies: Cost Structure and Scalability

2021 ◽  
Author(s):  
Mohammad Istiak Hossain ◽  
Jan I. Markendahl
Keyword(s):  
Communication Technology ◽  
Service Providers ◽  
Communication Technologies ◽  
Cost Structure ◽  
Small Scale ◽  
Area Network ◽  
Wide Area Network ◽  
Generic Framework ◽  
Cost Efficient ◽  
The Cost

AbstractSmall-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.

Sign in / Sign up

Export Citation Format

Share Document