LAUTECH Journal of Engineering and Technology (LAUJET)
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ANALYSIS OF VIBRATION EFFECT ON FACTORY FOUNDATION IN A FLOUR MILL
Get PDFThirteen roller machines, in operation at a flour mill, all on one floor, were analyzed for spectra transmission and propagation, using a vibration analyzer. The vibration analyzer was placed at 8 different positions around each roller machine, generating unique spectra curves symbolic of signals transmitted. It was observered that with exponential characteristics above 2 in the polynomial equations resulted in significant signal propagation requiring isolation of the machines necessary. Results indicates that out of the 7 machines requiring isolation, cork would be needed for 3 with maximum displacement of 0.19 to 0.20mm, while composite pad would be needed for 4 with a maximum displacement of 0.10 to 0.16mm. The study had shown that vibration effects could be successfully monitored on factory floors through the vibration analyzer application, thus, minimizing harzardous effects on factory workers and facilties
PERFORMANCE EVALUATION OF A THREE BOTTOM STANDARD DISC PLOUGH AT VARYING TILT AND DISC ANGLES
Get PDFPloughing which is the primary tillage operation aims at reducing the soil strength, cover plant residues, and rearrange soil aggregates. In this operation, considerable amount of farm tractor power is expended, and therefore efficient tillage system is desirable which minimizes the amount of energy required to till the soil. In this experiment, the combination of tilt and disc angle of a three bottom standard disc plough as they affect ploughing operation was studied in terms of width of cut, depth of cut, and volume of soil ploughed at a constant speed of 5.6km/hr. The test was carried out with five disc angles; 37o, 40o, 43o, 46o and 49o, in combination with five tilt angles; 15o, 20o, 22.5o, 25o, and 30o at constant ploughing length. The experiment was run at different passes of 3-blade combination maintained at 25 m ploughing length and data were taken at 5 m interval. The physicomechanical properties of the soil in the experimental plot were determined and found to be 6.7% soil moisture content (wb), bulk density is 1.53g/cm3, soil aggregate distribution of 7:1:2 (sand, silt and clay). The best performance of the three bottom standard disc plough was found at the combination of tilt angle in the range of 15o-25o, and 43o-46o disc angles. Ploughing below and beyond these values was not efficient
MEASUREMENT OF MEAN VELOCITY PROFILE IN A TURBULENT PIPE FLOW – A NUMERICAL APPROACH
Get PDFComputational Fluid Dynamics FLUENT codes were employed in the measurement of the mean velocity profile of a fully-developed pipe flow. The codes used the standard two equation eddy-viscosity () model for analysing turbulence in the flow. Deviations of about 2-12%, 1.1-1.7% and 1.02-5.3% obtained between the numerical results and the experimental benchmark for the study in the viscous sub-layer, buffer region and the fully-developed region of the flow show the close agreements between the experimental and the numerical results
ANALYSIS OF EXHAUST GAS EMISSIONS AND PERFORMANCE PARAMETERS ON NON- ROAD SPARK IGNITION ENGINES
Get PDFAir pollution continues to be a serious threat to the health and well-being of the population. Worldwide, tens of millions of spark ignition (S.I) engines are used for non-road applications such as electric generators, compressors, pumps hand held and non-hand held devices. This work investigated the effects of equivalence ratio, engine speed and engine load on exhaust gas emissions and performance parameters of non-road spark ignition engines. Three input parameters which are engine design/operating parameters and eight output parameters which are exhaust gas emissions and performance parameters were considered in this work. The effect of variation in the input parameters on the output parameters were simulated using software implemented in MATLAB 7.9 neural network toolbox environment developed by the authors. The results show that engine speed of 3000rpm gave the maximum values for several parameters considered. The results also show that exhaust gas emission and several performance parameters increased with increased in engine load. Equivalence ratio of 0.9 gave the least values for exhaust gas emission and specific fuel consumption. It can be concluded that for low exhaust gas emission and improved performance, non-road S.I engines should be operated at low engine loads engine speed of about 3000rpm and equivalence ratio of between 0.9 and 1.
IMPROVEMENT OF A SIMPLE TENSION INFILTROMETER FOR DETERMINING SOIL HYDRAULIC PROPERTIES
Get PDFAn improved design of an existing simple tension infiltrometer which could use easily available PVC pipes for its water reservoir is presented. The disc is made of cast aluminium and incorporates a reservoir pipe adapter to facilitate the use of multiple reservoir pipe sizes. The test results from the constructed infiltrometer in loamy sand showed the performance of the equipment to be consistent and satisfactory suggesting that the equipment would be useful in routine research instrumentation and sturdy enough for use in students’ practical works. It was considered valuable in our local situation where typically there are resource constraints for importing sophisticated instrumentation and components
PRODUCTION OF BIO-DIESEL FROM JATROPHA CURCAS SEED USING IN-SITU TECHNIQUE: EFFECT OF CATALYST AMOUNT AND ALCOHOL-SEED RATIO
Get PDFThe effect of alcohol seed ratio(0.5,1.5 & 2.0) and initial catalyst amount(0.5,1.0 & 1.5%) on the in-situ production of biodiesel from raw Jatropha Curcas seed was studied at a reaction temperature of 600C and reaction time of 120min. Central composite experimental design was applied to evaluate effects of alcohol-seed weight ratio (0.5 – 2.0) and initial catalyst amount (0.5 – 1.5%). Initial catalyst amount and alcohol seed ratio was found to have significant (P<0.05) effects on the yield. Initial catalyst amount was the more important factor and had a positive influence on the yield than alcohol seed ratio which does not significantly affect the yield as a single factor. Due to formation of by-products (soaps) caused by excessive amount of catalyst and excess alcohol leading to difficult ester separation from glycerol, there was a general reduction in Jatropha Curcas ethyl-ester as levels of catalyst and alcohol seed ratio increased. A second-order model was obtained to predict the yield as a function of all factors. The model predicted well the observed data with a R2 value of 0.985 and a non-significant Lack-of-Fit (P<0.05). The biodiesel obtained, compared favorably with the ASTM D6751-02 standard for biodiesel but the viscosity
RELATIONSHIP BETWEEN EXERGY, ENERGY, ECONOMICS AND ENVIRONMENT
Get PDFEnergy analysis of process has gained popularity overtime and has been used in detecting, quantifying and minimising inefficiencies in processes. This paper illustrates these and goes a step further in showing the relationship between exergy, energy, economics and environment. In today’s world of energy sensitivity, environmental concern and economics nose diving an understanding of exergy and its impact among these ties becomes highly significant. The study shows the potential usefulness of exergy analysis in solving energy related environmental problems, and in reducing cost of operating and designing process and hence, ultimately leading to sustainable development
EFFECT OF RICE HUSK ASH IN THE PRODUCTION OF HOLLOW SANDCRETE BLOCK
Get PDFThe effect of rice husk ash as a component of hollow sandcrete blocks was investigated. The objective was to reduce the present high cost of building construction. The rice hush ash used was derived from rice husk which is a bye-product of milling rice. Batching of the material was done by weight and a nominal mix proportion of 1:6 of cement and sand respectively was used. One hundred and twenty samples of hollow sandcrete blocks were produced in two different sizes 226x225x450 (mm) and 150x225x450(mm). Various proportions of rice husks ash i.e. 0%,4%,10%,20%, and 30% were used as replacement of cement in the mix. The compressive strength of the samples were determined after 28days using the universal testing machine and the average values obtained were 2.8, 2.2, 2.5, 2.0, and 1.7(N/mm2) respectively. It was concluded that rice husk ash blocks have relatively lower strength compared to blocks without rice husk ash. At 10% ash replacement however, the hollow block developed compressive value of 2.5N/mm2 which met the minimum standard required for building construction. Cost analysis showed that a saving of 5.3% per block can be achieved through the use of rice husk ash blocks. It was therefore recommended the rice block ash blocks with up to 10% replacement can be used in building construction for non-load bearing walls such as fence walls and partitions
COMPARATIVE ANALYSIS OF M-QAM SIGNALINGS SCHEMES PERFORMANCE OVER FAST AND FREQUENCY NON-SELECTIVE RAYLEIGH FADING CHANNEL WITH MRC RECEIVER
Get PDFThis paper presents a comparative analysis of some digital modulation signaling schemes over fast and frequency non selective Rayleigh fading channel with multiplicative distortion, addictive white Gaussian Noise (AWGN) and maximal ratio combining (MRC) at the receiver. Three M-ary (with m=4, 8, 16) modulation schemes are used as the channel input and a comparative analysis is carried out in terms of bit error rate (BER) averaged over the iterations (ABER) versus the signal-to-noise ratio(SNR) for different orders of the M-ary over the channel and the processing of the received signal by an MRC were simulated using MATLAB 7.0 application package. The result show that, of the three modulation schemes considered, the ABER performance for 4. Level quadrature amplitude modulated (QAM) signal is the best followed by that for 8QAM, while an excessive degradation is noticeable in the ABER performance of the 16QAM scheme when compared with the performances of the other two schemes even when an MRC receiver is used
THE DEVELOPMENT OF A SOLAR DEVICE FOR CROP DRYING AND COOKING
Get PDFAn absorber-type collector device for crop drying or cooking was fabricated and tested. It comprises of doubled-walled wooden box with a double glazed tight fitting lass lid. The gap between the walls of the box was stuffed with dry sawdust. A soot-coated, metal plate was attached to the bottom of the box as the heat absorber. Small pebbles also coated with soot, placed around the inner edges of the box act as heat storage medium. There were inlet and outlet ports with plastic pipes leading to and from the cooking chamber. Inlet air was made to pass through a container that was stuffed with dehydrating agent and from there, through a plastic tube into the chamber. There was a valve provided on the plastic tube. Air outlet was from the cooker through another plastic tube and leads into drying chamber. Both vales were closed when the device was operating as a cooker, and opened when it was operating as a dryer. It took 57minutes to cook beans, 37 minutes to cook yams and 43 minutes to cook rice, within the device, when there was bright sunshine. For the drying test, beef samples initially at 73% moisture content dried to 17% in 5 hours and cassava samples at 56% moisture content dried to 14% in 5 hours all in bright sunshine. The heat collection and conserving capacities of the device were found to be quite high ,with the maximum temperature reaching 1340c when in use as cooker. Temperature in the cooker was 740c after 5 hours after shut down