Small-scale Schemes Research Articles

Multi-resource spatio-temporal coordinated voltage regulation for active distribution network with multiple integrated energy stations under uncertainties

Integrated energy stations (IESs) are widely spread in power-electronized active distribution network (ADN) for multi-energy services, and heterogeneous uncertainties from source-loads exacerbate voltage violation risks with increasing penetration of distributed generators (DGs). Existing research has not explicitly revealed the spatio-temporal synergy adaptability of multiple response-otherness resources. This paper proposes a bi-level mixed-scale strategy to leverage multiple resources for voltage improvement under uncertainties. Upper level performs model predictive control (MPC)-based rolling for optimizing large-scale reserve-integrated coordination schemes of soft open points (SOPs) and thermal storage/demand; and reserve margins for building temperature are constrained for the sake of unpredictable environmental factors. In lower level, mixed-scale adjustment is applied in which ADN executes re-generated small-scale schemes and IESs obey large-scale schemes of upper level. SOPs’ rapid response abilities are invoked to tackle real-time errors while building temperatures vary within comfort range for responding to insensitive environmental fluctuations. Via sufficient flexibility assurance and mixed-scale coordination in separated levels, the voltage level is effectively facilitated. The original nonconvex model is relaxed into a second-order cone programming (SOCP) formulation, which can be effectively tackled for timely voltage regulation. Numerical results show the proposed strategy can realize spatio-temporal regulation of multiple resources for adapting to different-scale uncertainties, mitigating voltage deviation significantly.

Wage labor in rice cultivation areas near Lake Victoria in Western Kenya

Rice is now the most rapidly growing food commodity in sub-Saharan Africa. This growth is mainly driven by urbanization. There is substantial research on the wage labor dynamics in rice production in Asia, but in Africa, there is limited analysis of the labor used in rice cultivation-the attributes, numbers, and costs which make it difficult to understand the actual market, such as how products are procured. This study aims to fill this gap in the research by comparing wage labor factors in two rice cultivation areas in Kenya: Awach and Ahero. The role of wage labor in farm household management as well as in the economy of the areas is considered. The results, based on two surveys, show that, at the Awach small-scale scheme, the yield was low and the cultivation area small, generating profit per household of only about one-half that of the more large-scale Ahero scheme. High wage expenses at Awach put pressure on rice farming management because, although family labor was used for rice cultivation, additional labor was required for transplanting and weeding, incurring expenses. These were covered by sales of rice in the previous year or sales of livestock. In both areas, wage laborers were mostly people residing in the same area. In the case of Ahero, the scale of the scheme itself was large, and the hired laborers were unknown. However, in Awach, there was a high rate of hiring neighbors, and thus, wage labor costs could also be understood as a source of income for people in the area. Therefore, it can be inferred, in the case of Ahero, that there is a mechanism of wage labor based on economic principles, whereas in the case of Awach, small-scale production using family labor may be less efficient, but there is an additional concern with community principles. Key words: Rice cultivation, western Kenya, wage labor, economic principles, community principles.

Designing an economical slow sand filter for households to improve water quality parameters

Abstract Fresh and clean water is basic need for human health. However unclean and impure water creates access to illness and many diseases which influence the economic growth of the country. A very traditional method i.e. SSF has been used for removing fine suspended particles, microbes, minerals and flocs present in water. The aim of this research article is to invent and install an economic and non-conventional slow sand filter for treating water to resolve the issues related with impure water. Deigned SSF has been operated under the hydraulic loading of 4.6296 L/sec/m2 and an operational period of one hour. Cross sectional area of bed has been taken as 0.0576 m2. This technique is a small-scale scheme and easily employed for intermittent use that made it suitable for household purpose. Four processes namely Mechanical trappings, Predation, Adsorption and Natural death that has been taken place during the filtration process has been widely discussed in this paper. Various chemical and physical characteristics of water has been tested. Major parameters like pH, TDS, turbidity, Salinity, conductivity and salinity of filtered water have been tested for raw water and test results has been compared with Indian standard parameters. Various results from SSF revealed the successful removal of suspended solids, natural and organic materials from raw water. Test results shows that designed SSF is highly efficient for improving the household water quality parameters. Designed SSF removes large number of impurities as compared to other filters and it is socially acceptable.

Impact of effective rainfall on net irrigation water requirement: The case of Ethiopia

ABSTRACT Irrigation is one means to increase food supply besides the rain fed agriculture. During designing irrigation schemes most of the time effective rainfall is needed to be estimated in order to know the amount of water that should be supplied from irrigation. The problem is which effective rainfall determination method to be used is not clear among the available four built in methods in CROPWAT 8.0. Therefore, in this study analysis was made for Ethiopia case by considering selected 11 (eleven) small scale schemes from different parts of the country designed by different consultant companies. The finding shows most of the schemes designed in Ethiopia use either USDA-SC method (gives minimum net irrigation water requirement) or dependable rain method (results maximum net irrigation water requirement) in determination of effective rainfall. Moreover, additional study need to be conducted to test using soil–water balance method to identify which effective rainfall determination is the correct in planning and designing of irrigation schemes.

Decuplet to octet baryon transitions in chiral perturbation theory

We have systematically investigated the decuplet (T) to octet (B) baryon (Trightarrow Bgamma ) transition magnetic moments to the next-to-next-to-leading order and electric quadruple moments to the next-to-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. Throughout our calculation, we have adopted the small-scale scheme and have not considered the 1/M recoiling corrections directly. We count the octet and decuplet baryon mass splitting delta , the small momenta p, and the pion mass m_{phi } as the same order small-scale parameter, which was denoted as epsilon . Our results for the transition magnetic moments show reasonably good convergence of the chiral expansion. The analytical expressions may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.

Performance evaluation of reservoir-based irrigation schemes in the Upper East region of Ghana

The design of relevant adaptation strategies for water users in irrigation schemes in the drylands of Sub-Saharan Africa requires up-to-date information about the current performance of these schemes in view of rapid changes in climate and land use, population growth, and competing water demands. Previous assessments focused primarily on field-level crop irrigation; however, information on the performance of schemes as a whole and considering multple water users remains scarce. We examined two (one small- and one medium-scale) irrigation schemes shared by multiple users in the Upper East region of Ghana, including the water reservoir, water conveyance and distribution network, cropping fields, and the management entity. Multi-level performance indicators with relevance to water delivery and utilization as well as to agricultural production during two consecutive dry seasons were used. Technical factors, such as underutilized reservoir storage capacity and deteriorated conditions of water delivery infrastructure, strongly undermined the performance. In particular, the medium-scale irrigation scheme utilized less than 40% of total storage, whereas the small-scale scheme utilized about 70% of the storage. An examination of field-level water management practices suggests that an application efficiency of 58–68% is achievable in both schemes by improving the irrigation scheduling of the major crops. Overall system efficiency can be increased from 50% to 68% by reducing water conveyance network losses and by eliminating over-irrigation of fields. A holistic approach considering all competing water demands is needed for the performance evaluation of reservoir-based irrigation schemes in drylands.

Analysis of BJ493 diesel engine lubrication system properties

The BJ493ZLQ4A diesel engine design is based on the primary model of BJ493ZLQ3, of which exhaust level is upgraded to the National GB5 standard due to the improved design of combustion and injection systems. Given the above changes in the diesel lubrication system, its improved properties are analyzed in this paper. According to the structures, technical parameters and indices of the lubrication system, the lubrication system model of BJ493ZLQ4A diesel engine was constructed using the Flowmaster flow simulation software. The properties of the diesel engine lubrication system, such as the oil flow rate and pressure at different rotational speeds were analyzed for the schemes involving large- and small-scale oil filters. The calculated values of the main oil channel pressure are in good agreement with the experimental results, which verifies the proposed model feasibility. The calculation results show that the main oil channel pressure and maximum oil flow rate values for the large-scale oil filter scheme satisfy the design requirements, while the small-scale scheme yields too low main oil channel’s pressure and too high. Therefore, application of small-scale oil filters is hazardous, and the large-scale scheme is recommended.

Analysis of Irrigation Systems Employing Comparative Performance Indicators: A Benchmark Study for National Irrigation and Communal Irrigation Systems in Cagayan River Basin

Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains—(1) system operation performance; (2) agricultural productivity and economics; (3) financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute (IWMI) and Food and Agriculture Organization (FAO). Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System (MARIIS), Lucban, Garab and Divisoria Communal Irrigation Systems (CIS), respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.

Benchmarking for performance assessment of small and large irrigation schemes along the Senegal Valley in Mauritania

Degradation of irrigation schemes, low and variable land productivity, and inefficient use of production inputs are major concerns in Mauritania. That prompted this benchmarking analysis of 17 small and 3 large irrigation schemes located along the River Senegal. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley, and to inquire whether small schemes function better than large schemes. Cluster and data envelopment analyses enabled, respectively, grouping and ranking of irrigation schemes according to a set of pre-determined performance indicators: viz. energy costs, relative irrigation supply, irrigation intensity related to irrigable and equipped area, adequacy, and land productivity. Land productivity, which was highly variable, was compared to simulated land productivity for non-limiting conditions in order to determine yield gap variations. Few early sown crops were close to the simulated yield frontier of 10.6tha−1 and the mean yield was similar for large and small schemes (3.50tha−1 and 3.77tha−1, respectively). The analysis of the indicators revealed that, on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. Analysis of clusters identified three groups of irrigation schemes: viz. consuming and productive, precarious, and productive and economic. According to data envelopment analysis, four irrigation schemes were identified as technically efficient. Their average land productivity was relatively high (4.75tha−1) and energy costs were contained (59€ha−1). Data envelopment analysis also identified the particular efficient schemes that should be taken as reference for improvement of each inefficient scheme.

Can premium tariffs for micro-generation and small scale renewable heat help the fuel poor, and if so, how? Case studies of innovative finance for community energy schemes in the UK

In the UK, the introduction of micro-generation Feed in Tariffs (FiTs) and a proposed Renewable Heat Incentive (RHI) for domestic and small scale schemes have re-energised the market for investment in domestic scale renewable energy. These incentives may provide financial opportunities for those with capital to spend but for the record numbers with low incomes in ‘fuel poverty’, these benefits may seem out of reach. This paper shows that with appropriate financial intermediaries it is possible for renewable energy incentives to be used to alleviate fuel poverty.Simple financial analysis demonstrates the theoretical potential of FiTs to help those in fuel poverty. Two case studies of renewable energy projects in low income areas investigate how the incentives may be used in practice, what barriers exist and what success factors are evident. The analysis shows that local energy organisations (LEOs) are key if the poor are to access benefits from premium tariff schemes. Low interest finance mechanisms, good information sharing and community involvement are found as key success factors.

Economic assessments of small-scale drinking-water interventions in pursuit of MDG target 7C

This paper uses an applied rural case study of a safer water intervention in South Africa to illustrate how three levels of economic assessment can be used to understand the impact of the intervention on people's well-being. It is set in the context of Millennium Development Goal 7 which sets a target (7C) for safe drinking-water provision and the challenges of reaching people in remote rural areas with relatively small-scale schemes. The assessment moves from cost efficiency to cost effectiveness to a full social cost–benefit analysis (SCBA) with an associated sensitivity test. In addition to demonstrating techniques of analysis, the paper brings out many of the challenges in understanding how safer drinking-water impacts on people's livelihoods. The SCBA shows the case study intervention is justified economically, though the sensitivity test suggests ‘downside’ vulnerability.

Irrigation Water Value at Small-scale Schemes: Evidence from the North West Province, South Africa

Insight into the value of water is essential to support policy decision making about investments in the water sector, efficient allocation of water and water pricing. However, information on irrigation water values at small-scale schemes is scarce and in general little attention is paid to the determinants of these values. In this study values are calculated for small-scale irrigation schemes in the North West Province of South Africa, using the residual imputation method. An average water value of US$0.188/m3, in line with expectations for vegetable crops, was found. Furthermore, the crop choice and the irrigation scheme design and institutional setting were shown to significantly influence the water value, whilst individual characteristics of farmers proved to be less important.

Groundwater management in northern Iraq

Groundwater is vital and the sole resource in most of the studied region of northern Iraq. It has a significant role in agriculture, water supply and health, and the elimination of poverty in rural areas. Although Iraq is currently dramatically disturbed by complex political and socio-economic problems, in its northern part, i.e. the Kurdish-inhabited region, fast urbanization and economic expansion are visible everywhere. Monitoring and water management schemes are necessary to prevent aquifer over-exploitation in the region. Artificial recharge with temporary runoff water, construction of subsurface dams and several other aquifer management and regulation measures have been designed, and some implemented, in order to improve the water situation. Recommendations, presented to the local professionals and decision-makers in water management, include creation of Water Master Plans and Water User Associations, synchronization of drilling programmes, rehabilitation of the existing well fields, opening of new well fields, and the incorporation of new spring intakes in some areas with large groundwater reserves, as well as construction of numerous small-scale schemes for initial in situ water treatment where saline groundwater is present.

Is small beautiful? A multicriteria assessment of small-scale energy technology applications in local governments

In its 2003 White Paper the UK government set ambitious renewable energy targets. Local governments and households have an increasing role in the overall energy system as consumers, suppliers of smaller-scale applications and citizens discussing energy projects. In this paper, we consider if small-scale or large-scale approaches to renewable energy provision can achieve energy targets in the most socially, economically and environmentally (SEE) effective way. We take a local case study of renewable energy provision in the Metropolitan Borough of Kirklees in Yorkshire, UK, and apply a multi-criteria decision analysis methodology to compare the small-scale schemes implemented in Kirklees with large-scale alternatives. The results indicate that small-scale schemes are the most SEE effective, despite large-scale schemes being more financially viable. The selection of the criteria on which the alternatives are assessed and the assigned weights for each criterion are of crucial importance. It is thus very important to include the relevant stakeholders to elicit this information.

Water use in rice schemes in the Senegal river Delta and Valley

The water use of rice schemes was derived from field measurements made during the 1991 and 1992 season at 13 irrigation schemes situated in the delta and valley of the Senegal river. The seasonal water consumption, as well as the water distribution throughout the season and the operation of the pumping stations were evaluated. The water consumption was compared with standards which ranged from 16,650 to 21,100 m3 ha−1 depending on the season and the location of the scheme. Half of the analyzed schemes used more water than required. Analysis of the water distribution throughout the season revealed that in general the supply follows the demand. In small-scale schemes however, the fit between supply and demand is often lacking, resulting in crop stress and yield reduction. Furthermore, the study shows that the capacity of half of the pumping stations are under-used as a result of a long stretched saturation period and/or the irrigation of only a small fraction of the total area of the scheme.

Training engineering supervisors for small-scale irrigation development in Nigeria

Peoples' programme A very significant feature of the small-scale irrigation programme is that with a bit of ingenuity and tact it can be made a 'peoples' programme', and the community's active participation can be secured in its implementation. This will not only cut the costs of such schemes substantially, but will also encourage the people to think of these schemes as their own, which is very important to the success of any programme undertaken in the public sector. Obviously such a personal attachment is missing in any largescale project. Separate small-scale irrigation departments need to be set up in both the federal and state governments to encourage development. The benefits of small-scale irrigation should not be overlooked, and the The ultimate aim is the optimum use of the soil and water resources, and the adoption of appropriate technology within the framework of the particular socio-economic structure. Only the careful use of both surface and groundwater together will have a dramatic effect on increased food production. Small-scale schemes are attractive because the initial outlay involved is small, they can be executed quickly and yield quick results, they normally require no special expertise or equipment, and local expertise and resources (including human resources) can be easily mobilized for their execution. The disadvantages, however, are their cost of maintenance, their relatively short life, and the limited protection they afford. Because of the current funding constraints; the urgent need to curb food imports; the lack of well-trained, technical personnel and sophisticated construction equipment; and the need to make full use of our human and material resources; these smallscale schemes are often very appropriate. where large projects are suitable, and there are others where only small schemes are possible. Still others may offer a chance to blend the two. In the northern part of the country a large number of seasonal streams could be tapped by constructing small storage tanks made of earthen dams and their canal systems, while in the south numerous perennial streams could be harnessed by constructing masonry THE CONFLICTING roles of the large-scale and small-scale irrigation schemes in the green revolution programme, and the economics of such schemes, are often questioned. There should in fact be no conflict between these two types of schemes, because they are complementary to and not competitive with each other. In a large, geographically varied country like Nigeria, there should be ample scope for both. There are parts of the country

Computerised irrigation scheduling using spreadsheet models

Microcomputers are increasingly being used to help in the management of smallholder irrigation schemes in Third World countries. In many cases, commercially available spreadsheet packages offer advantages over established scientific programming languages. The paper starts with a review of computer models which have been developed for irrigation scheduling. Two criteria are identified which must be considered when developing computer models for this purpose: realistic data requirements and programs which are easy to understand. Spreadsheet packages provide a good introduction to computing and macro programming techniques can be used to customise spreadsheet models to create refined yet simple management tools. Two practical examples are presented from current research projects: -a small scale scheme in Zimbabwe, where a spreadsheet model is used to produce irrigation schedules for smallholder farmers; -a 20,000 ha project in Thailand, where a spreadsheet model makes use of feedback to improve main system scheduling.

Analysis of the Weliwewa and Maththala settlement schemes under the Hambantota Integrated Rural Development Programme (HIRDEP)

Hassendeen, S. 1983. Analysis of the Weliwewa and Maththala settlement schemes under the Hambantota Integrated Rural Development Programme (HIRDEP). Norsk geogr. Tidsskr. Vol. 37, 159–170. Oslo. ISSN 0029-1951. Initial studies of two settlement projects are presented. These projects are among the first small-scale schemes to settle people around minor tanks as reservoirs in Sri Lanka. Their potential for regional development is discussed. The size of holdings, dependence of agriculture on rainfall alone, and lack of a proper marketing system are perceived as major obstacles to the success of the projects. Active settler participation, crop diversification and better social and physical infrastructure (such as roads, extension services, institutional support and non-farm employment), are, however, pillars upon which the success of the programme depends.