จำนวน Repository ( 816 )

Wind turbine simulator based on constant Volts/Hertz control   three phase induction motor drives
Wind turbine simulator based on constant Volts/Hertz control three phase induction motor drives

This article presents the application of the constant Volts per Hertz control to control a three phase induction motor has torque and speed characteristics similar to wind turbine. Due to this method is not complicated and does not require the parameters of motor. As a result the accuracy of control is independent of variation of the parameters of motor. Furthermore the equation for compensate the difference between the moment of inertia of wind turbine and motor which is consistent with the mentioned control method is proposed. In order to make the dynamic responses of the wind turbine simulator similar to the wind turbine and to overcome the problems of noise amplification from differentiation that leads to instability of the system. The simulation results in Matlab/Simulink program show that the proposed wind turbine simulator can imitate the wind turbine accurately both in dynamic and steady state conditions

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Compressive strength determination of bottom ash mixed with dust stone and portland cement
Compressive strength determination of bottom ash mixed with dust stone and portland cement

This research was to determine the appropriated mixing ratio of bottom ash and admixture (dust rock and Portland cement type 1) for improving the compressive strength. Bottom ash was used instead of soil and the quantities of admixture were 0 2 4 6 8 and 10% by dry weight of bottom ash. The specimens were cured for 7 14 28 and 90 days. Results of compressive strength test show that the admixture of 8% was the best mixing ratio. The increasing primary strength is developed from hydration reaction and the increasing secondary strength at 90 days is developed from pozzolanic reaction. Moreover the compressive strength of this specimen is close to the compressive strength of laterite

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Effect of bottom ash as fine aggregate on strength of concrete
Effect of bottom ash as fine aggregate on strength of concrete

This research was aimed to study the effect of bottom ash (BA) as fine aggregate in fly ash concrete and cement-only concrete on strength of water-cured and uncured concrete. The water to binder ratios were 0.35 and 0.55 to represent high strength and normal strength concrete respectively. The weight percentages of replacement of cement by fly ash were 0 and 30%. The replacement ratios of bottom ash as fine aggregate were 0 10 and 30% by volume of fine aggregate. The results indicated that the slump and setting time of concrete increased with the increase of bottom ash content. In contrast the compressive and tensile strength decreased with the increase of bottom ash content. From the curing sensitivity index it was showed that the fly ash concrete required longer curing period than cement-only concrete. In case of high strength concrete the use of bottom ash in fly ash concrete can reduce curing sensitivity of concrete

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Properties of footpaths slab agasse Ash Concrete
Properties of footpaths slab agasse Ash Concrete

This research was aimed to studying the effect of bagasse ash on the properties of footpaths concrete slabs. Using bagasse ash a waste from the manufacture of ethanol instead of the OPC type I 10 20 30 40 and 50 percent by weight. Test results revealed that the compressive strength of concrete bagasse ash mixtures was less than the plain OPC type I concrete And decreased by the content of the bagasse ash. The flexure strength of the footpaths concrete slabs was laid in the same direction. Comparison flexure strength of footpaths concrete slabs on the standard (TIS 378-2531) found that can used 40% replacement of bagasse ash replacing in cement. For the percentage of water absorption of footpaths concrete slabs in bagasse ash concrete mixtures were higher than the plain OPC type I concrete mixture and every mixture is not exceeding standard. It was also found that the replacing cement with bagasse ash content increased the cost of footpaths concrete slabs were lower down. When replacing cement with bagasse ash in 40% cheaper than the cost of plain cement were up to 31% and according to the standard

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The development of rotary dryer for paddy  using Hot Air recovery system
The development of rotary dryer for paddy using Hot Air recovery system

This research’s objectives were to develop an energy saving rotary dryer for paddy using hot air recovery system and to evaluate the energy using. Rotary dryer divided rotating cylinder made of 304 stainless steel 2 mm of thickness 39 cm and 200 cm of diameter and length. The inverter was used to control speed of gear motor of 0.5 HP and rotating speeds of 1-3 rpm. The inside of cylinder composed screw and capture flights. The cyclone system was used to dust separating from the system. The moisture trap contained silica gel the outlet hot air was reduced moisture and recovered using. The fiber glass insulator was applied for reducing energy loss. The heating box composed 3 set of 1600 W heaters and blower motor power was 0.5 HP. In the experiment the drying temperature was varied of 50 60 70 and 80oC and cylinder speed was varied of 1 2 and 3rpm (15.66 10.66 and 5.66min of drying time). The initial moisture content of 10 kg paddy was 29.7?0.6 %wb. The result show that the optimum conditions drying temperature and cylinder speed were 70-80oC and 1 rpm (15.66 min) and final moisture content was 9.2-11.8 %wb. From the save energy testing found that the reducing of SEC was 0.4-0.6 MJ/kg water per drying cycle. There for this developed dryer can save energy using

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