จำนวน Repository ( 1087 )
Mechanical properties of concrete mixed with reused ceramic tiles reinforced with steel fiber from milling processed
This research study the mechanical properties of concrete mixed with reused ceramic tiles reinforced with steel fiber from milling processed. The compressive strength of all concretes were designed at 300 ksc at 28 days and control slump in the range of 10 ? 2.5 cm. The steel fiber from milling processed was reinforced at 0.50 1.00 and 1.50 by the weight of cement content. The compressive strength Flexural and tensile splitting for all concrete samples were tested compare with control concrete which it as concrete mixed with reused ceramic tiles not reinforced with steel fiber. The results shown that the reinforcing with steel fiber from milling process at 0.5 and 1.0% was affect to the higher compressive strength than control concrete of 2 and 7% but increasing steel fiber at 1.5% was affect to lower compressive strength than control concrete of 6%. Concrete mixed with steel fiber from milling processed at 1.0% have higher splitting tensile strength than control concrete of 16% while concrete mixed with steel fiber at 0.5 and 1.5% have splitting tensile strength equal with control concrete. The flexural strength of these concretes have higher more than control concrete about 9 17 and 11% for reinforcing with steel fiber at 0.50 1.00 and 1.50 respectively. In addition the water permeability of concretes were increased when the steel fiber were reinforced increases too.
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
Design of cmos voltage reference circuit
This paper presents a CMOS voltage reference design which is widely used in electronic circuits both analog and digital circuits. In the conventional a CMOS voltage reference circuit design composed of several MOS transistors and complicated circuits the output voltage cannot be adjusted to any levels. Therefore in this paper proposed the CMOS voltage reference circuit design technique based on a new current combination circuit which it was reduced number of MOS transistors and the proposed circuit is able to operate without complex startup circuit. The performance of the proposed circuit is confirmed through PSPICE simulation results the circuit can be operated with supply voltage varies from 2V to 4V the output voltage reference is about 231 2mV at wide temperature range of -80 to 120 it has very low temperature coefficient of about 37.65 ppm/ and a total power dissipation of 7.37 W
Dry reforming of methane reaction for hydrogen and syngas production using cobalt catalysts and nickel-cobalt bimetallic catalysts
The cobalt catalysts (cobalt content by weight: 7% 10% and 15%) and cobalt-nickel bimetallic catalysts (cobalt-nickel content by weight: 3.5%-3.5% 5%-5% and 7%-7%) were studied in dry reforming of methane for hydrogen and syngas production. All catalysts were synthesized by the wetness impregnation method. The dry reforming of methane was carried out at 700oC atmosphere pressure using a mixture; CH4 and CO2 in ratio 1:1. The result showed that the good activity and stability depend on metal content in catalysts and the combined 2 metals as bimetallic catalysts. The optimum amounts of catalysts are 10wt% Co for mono-metallic catalysts 75%CH4 and 75%CO2 conversion and 7wt% Ni-7wt% Co for bimetallic catalysts 87%CH4 and 89%CO2 conversion.
Nutritive values evaluation of moringa leaves meal for broiler feed ingredient
Nutritive values moringa leaves meal were evaluated and compared with luecaena leaves meal which has similar chemical compositions in order to use moringa leaves meal as broiler chicken feed ingredient. Thirty 3-week old chickens were divided into 3 groups of 10 birds (5 males 5 females) each. Each chicken was randomly fed with experimental diet that was composed with cassava powder (for endogenous nitrogen analysis) powdered moringa Leaves meal and powdered luecaena Leaves meal. The chickens were raised individually in metabolic cage where feed and water were provided ad libitum and both feed intake and feces weight were recorded. Experimental diets and excreta were sampled and subjected to proximate analysis for chemical compositions and gross energy. T-test comparison was used for statistical analysis. Results indicated that nutrients utilization of moringa Leaves meal (utilization percentage of dry matter organic matter protein crude fiber nitrogen free extract energy and metabolizable energy) were higher than those of luecaena Leaves meal (P<0.01). However there was no statistical difference (P>0.05) between moringa Leaves meal and luecaena Leaves meal in utilization percentage of ether extract. Moreover usable energy of moringa leaves meal was also higher than that of luecaena leaves meal (p<0.01). Therefore moringa Leaves meal could be one of potential feedstuffs for use in broiler diet production.