Liquid jet pumped by rising gas bubbles

A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature

Improving agricultural productivity for poverty alleviation through integrated service provision with public-private sector partnerships: Examples and issues

Irrigation management / Crop production / Productivity / Constraints / Poverty / Farmers’ associations / Public sector / Private sector / Models / Food security / Sugarcane / Rice

Asset price bubbles: implications for monetary, regulatory, and international policies

Monetary policy ; Price regulation

Delay Learning Architectures for Memory and Classification

We present a neuromorphic spiking neural network, the DELTRON, that can remember and store patterns by changing the delays of every connection as opposed to modifying the weights. The advantage of this architecture over traditional weight based ones is simpler hardware implementation without multipliers or digital-analog converters (DACs) as well as being suited to time-based computing. The name is derived due to similarity in the learning rule with an earlier architecture called Tempotron. The DELTRON can remember more patterns than other delay-based networks by modifying a few delays to remember the most 'salient' or synchronous part of every spike pattern. We present simulations of memory capacity and classification ability of the DELTRON for different random spatio-temporal spike patterns. The memory capacity for noisy spike patterns and missing spikes are also shown. Finally, we present SPICE simulation results of the core circuits involved in a reconfigurable mixed signal implementation of this architecture.Comment: 27 pages, 20 figure

Health risks of irrigation with untreated urban wastewater in the southern Punjab, Pakistan

Irrigation water / Water quality / Water reuse / Waste waters / Risks / Public health / Diseases / Farmers / Pakistan / Southern Punjab / Haroonabad

Combined radiation, convection, and conduction for a system with a partially transmitting wall

The net radiation method is developed for systems having both opaque and partially transparent walls. Heat convection is present at the surfaces and heat conduction through the windows is taken into account. Specific equations are derived for a window between two parallel plates, where one plate is at an elevated temperature typical of what would be encountered in an electric furnace, and the other plate is being cooled. A two-band model is used with cutoff wavelengths typical of glass or quartz. Numerical results are obtained for the window temperature and the heat flow through the window. The effect on these quantities of various plate temperatures and emissivities is shown

Energy poverty in rural and urban India : are the energy poor also income poor ?

Energy poverty is a frequently used term among energy specialists, but unfortunately the concept is rather loosely defined. Several existing approaches measure energy poverty by defining an energy poverty line as the minimum quantity of physical energy neededto perform such basic tasks as cooking and lighting. This paper proposes an alternative measure that is based on energy demand. The energy poverty line is defined as the threshold point at which energy consumption begins to rise with increases in household income. This approach was applied to cross-sectional data from a comprehensive 2005 household survey representative of both urban and rural India. The findings suggest that in rural areas some 57 percent of households are energy poor, versus 22 percent that are income poor. For urban areas the energy poverty rate is 28 percent compared with 20 percent that are income poor. Policies to reduce energy poverty would include support for rural electrification, the promotion of more modern cooking fuels, and encouraging greater adoption of improved biomass stoves. A combination of these programs would play a significant role in reducing energy poverty in rural India.Energy Production and Transportation,Rural Poverty Reduction,Energy and Environment,Environment and Energy Efficiency,Energy Demand

Can social safety nets alleviate seasonal deprivation ? evidence from northwest Bangladesh

This paper examines the role of social safety-net programs in Bangladesh run by the government and nongovernmental organizations to mitigate seasonal deprivation in the country's highly vulnerable northwest region. Specifically, the paper explores whether social safety nets are limited to averting seasonal deprivation or can also address seasonality of income and employment more generally. Using a recent survey from the greater Rangpur (northwest) region, the paper finds that social safety nets have a positive effect on mitigating both seasonal and non-seasonal food deprivation. The results are robust, owing to the recent expanded coverage of social safety-net programs run by nongovernmental organizations active in the region. But given the annual recurrence of monga (seasonal food insecurity) in the northwest region owing to agricultural seasonality and an overwhelming dependence on agriculture for livelihoods, social safety nets are not a reliable tool for monga eradication. Programs are also needed to promote the income and productivity of the poor through diversification of income and employment.Safety Nets and Transfers,Rural Poverty Reduction,Food&Beverage Industry,Regional Economic Development,Housing&Human Habitats

Welfare impacts of rural electrification : a case study from Bangladesh

Lack of access to electricity is one of the major impediments to growth and development of the rural economies in developing countries. That is why access to modern energy, in particular to electricity, has been one of the priority themes of the World Bank and other development organizations. Using a cross-sectional survey conducted in 2005 of some 20,000 households in rural Bangladesh, this paper studies the welfare impacts of households'grid connectivity. Based on rigorous econometric estimation techniques, this study finds that grid electrification has significant positive impacts on households'income, expenditure, and educational outcomes. For example, the gain in total income due to electrification can be as much as 30 percent and as low as 9 percent. Benefits go up steadily as household exposure to grid electrification (measured by duration) increases and eventually reach a plateau. This paper also finds that rich households benefit more from electrification than poor households. Finally, estimates also show that income benefits of electrification on an average exceed cost by a wide margin.Energy Production and Transportation,Access to Finance,Engineering,Electric Power,Rural Poverty Reduction