Investigation of the Stability of Engine – Governor System Operated At Low Speeds

During diesel engine operation, a tendency for the engine not to achieve a  steady idling speed has often been observed. During idling speed the engine tends to either race or stall as a result of poor and incorrect metering of the fuel, which is required for the combustion process and if severe, the engine will stop firing completely. 111 this research an investigation was made to establish knowledge on diesel engine stability operated at low speeds. The influence of a governor of an engine in the control of the engine speeds has also been investigated. In order to obtain information on the engine operation condition, use has been made of a mathematical model that incorporates the engine, governor and a tachometer. A simulation was conducted by solving the system's differential equations using a fourth order Runge-Kutta numerical integration method written in C code computer programs. The results obtained show the stability of the engine-governor system operated at low speed to be stable. When the engine was subjected to some parameter variations the engine showed some sign of instability occurring at increased disturbance intensities. Based on the obtained results an enhanced knowledge has been obtained giving an indication on how the existing mechanical engine speed governors design features could be improved to achieve engine stability at low speeds

Thermolysis and Kinetics of Scrap Tyre and Bagasse for Energy Utilization

The increase of energy demand has brought concern to find alternative fuel that will at least sustain the requirement. Bagasse and scrap tyre are waste generated in our industrial activities, which can be used in energy production to subsidize the demand. This paper, aim to study the decomposition behaviour and kinetics of biomass (bagasse) and scrap tyre as preliminary stage of fuel sample analysis to be considered for energy production in gasification/combustion or pyrolysis facilities. The behaviour demonstrated with thermogravimetric analyzer (TGA), shows that all samples have high volatile amount release, 84.21% for bagasse and 85.08% for scrap tyre, which means all are suitable for pyrolysis. However, scrap tyre is most suitable for gasification or combustion due to its high energy content, high ash content and low moisture than bagasse. The determined kinetic parameter were activation energy (E) and pre-exponential factor (A) for hemicellulose/oil as first release composite and cellulose/elastomer as second composite of the analyzed bagasse/scrap tyre samples. The hemicelluloses of bagasse exhibited highest value of activation energy and pre-exponential factor (E=178.191 kJ/mol, and A=1.74×10 16 ) than oil of scrap tyre (E=41.113 kJ/mol, and A= 495.5), which means bagasse is suitable candidate for gasification process due to high operating temperature. With this respect of the study, all candidates may be suitable for pyrolysis or gasification/combustion process. However, for environmental consideration scrap tyre is not suitable due to high sulphur (S) and nitrogen (N) content resulting to high emission ofSOX and NOX 

Characterization and reactivity of soot from fast pyrolysis of lignocellulosic compounds and monolignols

peer-reviewedThis study presents the effect of lignocellulosic compounds and monolignols on the yield, nanostructure and reactivity of soot generated at 1250  ° C in a drop tube furnace. The structure of soot was characterized by electron microscopy techniques, Raman spectroscopy and electron spin resonance spectroscopy. The CO2 reactivity of soot was investigated by thermogravimetric analysis. Soot from cellulose was more reactive than soot produced from extractives, lignin and monolignols. Soot reactivity was correlated with the separation distances between adjacent graphene layers, as measured using transmission electron microscopy. Particle size, free radical concentration, differences in a degree of curvature and multi-core structures influenced the soot reactivity less than the interlayer separation distances. Soot yield was correlated with the lignin content of the feedstock. The selection of the extraction solvent had a strong influence on the soot reactivity. The Soxhlet extraction of softwood and wheat straw lignin soot using methanol decreased the soot reactivity, whereas acetone extraction had only a modest effect

Geophysical Exploration for Groundwater Resouces Potential over Basement Formations at Kwandolwa And Mwisho Wa Shamba Villages, Korogwe Distict, Tanzania

In this paper results of geophysical exploration studies to identify potential areas with groundwater resources at Kwamndolwa and Mwisho wa Shamba Villages in Korogwe District have been presented. The resistivity curves of eight sites at the two study areas were obtained using field data measurements made based on the application of a vertical electrical sounding (VES) method. The resisivity values obtained for sites VES-K3 and VES-M2 were found to be 10.9 and 24.0 ohm-m respectively. The interpretation of the resisivity values made for the two sites gave also an indication of the presence of sedimentary rocks composed of sandstone materials at the basements, known to constitute a good water bearing potential. These results are to be used as a guideline for borehole siting, providing information on the depth to the groundwater relevant to the development of effective water supply schemes at the study areas. Verification of the exact quality of water will be obtained during drilling test

The Development of Groundwater for Water Supply

Abstrac

The Study of Kinetic Properties and Analytical Pyrolysis of Coconut Shells

The kinetic properties of coconut shells during pyrolysis were studied to determine its reactivity in ground form. The kinetic parameters were determined by using thermogravimetric analyser. The activation energy was 122.780 kJ/mol. The pyrolysis products were analyzed using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). The effects of pyrolysis temperature on the distribution of the pyrolytic products were assessed in a temperature range between 673 K and 1073 K. The set time for pyrolysis was 2 s. Several compounds were observed; they were grouped into alkanes, acids, ethers and alcohols, esters, aldehydes and ketones, furans and pyrans, aromatic compounds, and nitrogen containing compounds. The product compositions varied with temperature in that range. The highest gas proportion was observed at high temperature while the acid proportion was observed to be highest in coconut shells, thus lowering the quality of bio-oil. It has been concluded that higher pyrolysis temperature increases the amount of pyrolysis products to a maximum value. It has been recommended to use coconut shell for production of gas, instead of production of bio-oil due to its high proportion of acetic acid