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Oxy-fuel carbon capture in power plants is a relatively new concept aiming at reducing carbon dioxide emissions from the plants. This is achieved by burning the fossil fuel using oxygen as oxidizer with no nitrogen, thereby rendering the exhaust gases very rich in carbon dioxide (after condensing water vapor by cooling), which facilitates its capture for environmental or commercial purposes. Despite the worldwide interest in oxy-fuel carbon capture, its progress is at risk given the large energy needed to separate oxygen from air in order to provide the oxidizer, thereby hindering further progress of this concept toward large-scale applications. This paper focuses on alleviating this drawback of oxy-fuel combustion by making it more attractive through combining it with another concept, namely magnetohydrodynamic (MHD) power generators. The end product is a power plant operating on a combined cycle composed of a topping MHD ultra-high-temperature cycle with direct electricity extraction from plasma, followed by a bottoming steam cycle with conventional turbo-generators. Different design aspects and simplified technical analysis for the MHD generator are presented.

Oxy-fuel carbon capture in power plants is a relatively new concept aiming at reducing carbon dioxide emissions from the plants. This is achieved by burning the fossil fuel using oxygen as oxidizer with no nitrogen, thereby rendering the exhaust gases very rich in carbon dioxide (after condensing water vapor by cooling), which facilitates its capture for environmental or commercial purposes. Despite the worldwide interest in oxy-fuel carbon capture, its progress is at risk given the large energy needed to separate oxygen from air in order to provide the oxidizer, thereby hindering further progress of this concept toward large-scale applications. This paper focuses on alleviating this drawback of oxy-fuel combustion by making it more attractive through combining it with another concept, namely magnetohydrodynamic (MHD) power generators. The end product is a power plant operating on a combined cycle composed of a topping MHD ultra-high-temperature cycle with direct electricity extraction from plasma, followed by a bottoming steam cycle with conventional turbo-generators. Different design aspects and simplified technical analysis for the MHD generator are presented.

The knowledge of physical and mechanical properties of onion bulb is important for successful design of any planter. Multiplier onion is propagated through bulbs and bulbs are planted manually. Manual planting of onion bulb is highly labour intensive (80-100 man-days ha-1) due to the close plant geometry (plant to plant and row to row spacing is 10 × 15 cm) among the vegetable crops. Engineering properties of multiplier onion were determined in order to design and develop a tractor operated raised bed onion bulb planter. In multiplier onion each onion comprises of 4-5 bulbs. These bulbs were cleaned, separated into single bulbs and divided in to 9 categories manually based on their individual weight viz., <2g, 2-3 g, 3-4 g, 4-5 g, 5-6 g, 6-7 g, 7-8 g, 8-9 g, >9 g. The onion bulb had a moisture content of 80.62±0.87 %. It was observed that the properties varied for different sizes of onion grades and the grades had highly significant effect on most of the properties. The linear dimensions of onion bulbs viz., length, width, thickness for nine grades ranged from 21.21±2.60 to 32.31±3.30 mm, 13.54±1.77 to 30.95±2.91 mm and 10.91±1.40 to 22.63±2.15 mm. The geometric mean diameter, sphericity, shape index and projected area all ranged from 28.22±2.04 to 14.54±0.96 mm, 0.87±0.06 to 0.69±0.08, 1.78±0.32 to 1.22±0.14 and 5.50±0.51 to 1.55±0.30 cm2, respectively. The one hundred onion bulb weight, bulk density, true density were in the range of 1185±19.59 to 121.6±6.30 g, 793.20± 9.45 to 480.19±13.13 kg.m-3, 1086± 205.22 to 1013.6±348.85 kg.m-3, respectively. The angle of repose decreased with increase in size of onion bulbs. The interaction between sphericity, shape index and angle of repose indicated that as the size of the onion size increase angle of repose decreased.

The knowledge of physical and mechanical properties of onion bulb is important for successful design of any planter. Multiplier onion is propagated through bulbs and bulbs are planted manually. Manual planting of onion bulb is highly labour intensive (80-100 man-days ha-1) due to the close plant geometry (plant to plant and row to row spacing is 10 × 15 cm) among the vegetable crops. Engineering properties of multiplier onion were determined in order to design and develop a tractor operated raised bed onion bulb planter. In multiplier onion each onion comprises of 4-5 bulbs. These bulbs were cleaned, separated into single bulbs and divided in to 9 categories manually based on their individual weight viz., <2g, 2-3 g, 3-4 g, 4-5 g, 5-6 g, 6-7 g, 7-8 g, 8-9 g, >9 g. The onion bulb had a moisture content of 80.62±0.87 %. It was observed that the properties varied for different sizes of onion grades and the grades had highly significant effect on most of the properties. The linear dimensions of onion bulbs viz., length, width, thickness for nine grades ranged from 21.21±2.60 to 32.31±3.30 mm, 13.54±1.77 to 30.95±2.91 mm and 10.91±1.40 to 22.63±2.15 mm. The geometric mean diameter, sphericity, shape index and projected area all ranged from 28.22±2.04 to 14.54±0.96 mm, 0.87±0.06 to 0.69±0.08, 1.78±0.32 to 1.22±0.14 and 5.50±0.51 to 1.55±0.30 cm2, respectively. The one hundred onion bulb weight, bulk density, true density were in the range of 1185±19.59 to 121.6±6.30 g, 793.20± 9.45 to 480.19±13.13 kg.m-3, 1086± 205.22 to 1013.6±348.85 kg.m-3, respectively. The angle of repose decreased with increase in size of onion bulbs. The interaction between sphericity, shape index and angle of repose indicated that as the size of the onion size increase angle of repose decreased.

Gas turbine (GT) power plants operating in arid climates suffer a decrease in output power during the hot summer months because of insufficient cooling. Cooling the air intake to the compressor has been widely used to mitigate this shortcoming. An energy analysis of a GT Brayton cycle coupled to a refrigeration cycle shows a promise for increasing the output power with a little decrease in thermal efficiency. A thermo-economics algorithm is developed and applied to an open cycle, Hitachi MS700 GT plant at the industrial city of Yanbu by the Red Sea in the Kingdom of Saudi Arabia. Result shows that the enhancement in output power depends on the degree of chilling the air intake to the compressor (a 12 - 22 K decrease is achieved). For this case study, maximum power gain ratio (PGR) is 15.46%, at a decrease in thermal efficiency of 12.25%. The cost of adding the air cooling system is also investigated and a cost function is derived that incorporates time-dependent meteorological data, operation characteristics of the GT and the air intake cooling system and other relevant parameters such as interest rate, lifetime, and operation and maintenance costs. The profit of adding the air cooling system is calculated for different electricity tariff.

Gas turbine (GT) power plants operating in arid climates suffer a decrease in output power during the hot summer months because of insufficient cooling. Cooling the air intake to the compressor has been widely used to mitigate this shortcoming. An energy analysis of a GT Brayton cycle coupled to a refrigeration cycle shows a promise for increasing the output power with a little decrease in thermal efficiency. A thermo-economics algorithm is developed and applied to an open cycle, Hitachi MS700 GT plant at the industrial city of Yanbu by the Red Sea in the Kingdom of Saudi Arabia. Result shows that the enhancement in output power depends on the degree of chilling the air intake to the compressor (a 12 - 22 K decrease is achieved). For this case study, maximum power gain ratio (PGR) is 15.46%, at a decrease in thermal efficiency of 12.25%. The cost of adding the air cooling system is also investigated and a cost function is derived that incorporates time-dependent meteorological data, operation characteristics of the GT and the air intake cooling system and other relevant parameters such as interest rate, lifetime, and operation and maintenance costs. The profit of adding the air cooling system is calculated for different electricity tariff.

Agricultural production depends upon certain crucial inputs e.g., water, fertilizer etc. In the less developed regions of South Asia in general, and the indo-Pakistan sub-continent in particular, the use of these inputs depends not only upon the financial affordability but also upon the institutional accessibility of farmers to these inputs. Besides high economic costs, bureaucratic controls and corruption regarding the distribution of inputs have created problems of limited accessibility, especially to the small farmers. In the absence of any credit, information and/or input distribution networks, the use of these inputs, and related productivity gains, become confined to that class of farmers which not only has better access to these inputs but is capable of using them in the best possible way e.g. use of water and fertilizer in the appropriate amount and at the appropriate time. This paper attempts to study how input use and input productivity vary across farm sizes, with some reference to the infrastructural and institutional factors, whose development play an important role in improving the distribution and productivity of inputs. For such an analysis, a comparison of the two Punjabs i.e. Pakistani and Indian Punjabs, presents an ideal framework, Separated by a national boundary since 1947, the two Punjabs enjoy a common history and culture, similar agricultural practices and agro-climatic conditions, Government policies in the two Punjabs, however, have not only differed between the two provinces at the same time, but also over time in the same province. It may be noted that due to certain policy measures, land distribution, tenancy conditions, promotion of agricultural co-operatives and provision of infrastructural features, such as roads and electricity, are relatively more improved in Indian than Pakistani Punjab.

Agricultural production depends upon certain crucial inputs e.g., water, fertilizer etc. In the less developed regions of South Asia in general, and the indo-Pakistan sub-continent in particular, the use of these inputs depends not only upon the financial affordability but also upon the institutional accessibility of farmers to these inputs. Besides high economic costs, bureaucratic controls and corruption regarding the distribution of inputs have created problems of limited accessibility, especially to the small farmers. In the absence of any credit, information and/or input distribution networks, the use of these inputs, and related productivity gains, become confined to that class of farmers which not only has better access to these inputs but is capable of using them in the best possible way e.g. use of water and fertilizer in the appropriate amount and at the appropriate time. This paper attempts to study how input use and input productivity vary across farm sizes, with some reference to the infrastructural and institutional factors, whose development play an important role in improving the distribution and productivity of inputs. For such an analysis, a comparison of the two Punjabs i.e. Pakistani and Indian Punjabs, presents an ideal framework, Separated by a national boundary since 1947, the two Punjabs enjoy a common history and culture, similar agricultural practices and agro-climatic conditions, Government policies in the two Punjabs, however, have not only differed between the two provinces at the same time, but also over time in the same province. It may be noted that due to certain policy measures, land distribution, tenancy conditions, promotion of agricultural co-operatives and provision of infrastructural features, such as roads and electricity, are relatively more improved in Indian than Pakistani Punjab.