Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54814
S. K. Debrah, E. Akaho, A. Ayensu
Numerical experiments on one dimensional convective coolant flow during steady state operation of the Ghana Research Reactor-1 (GHARR-I) were performed to determine the thermal hydraulic parameters of temperature, density and flow rate. The computational domain was the reactor vessel, including the reactor core. The maxi-mum coolant temperature attained during steady state operation was 68.3218 °C, while the density and velocity values were 0.9423 kg/cm3 and 1.0241 cm/s, respectively. The minimum values of the temperature, density and velocity were 40.2935 °C, 0.8495 kg/cm3 and 1.0108 cm/s, respectively. The experimental data indicated that the reactor is inherently safe during steady state or normal operations.
{"title":"Numerical experimentation on convective coolant flow in Ghana Nuclear Research Reactor - I","authors":"S. K. Debrah, E. Akaho, A. Ayensu","doi":"10.4314/JAST.V15I1-2.54814","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54814","url":null,"abstract":"Numerical experiments on one dimensional convective coolant flow during steady state operation of the Ghana Research Reactor-1 (GHARR-I) were performed to determine the thermal hydraulic parameters of temperature, density and flow rate. The computational domain was the reactor vessel, including the reactor core. The maxi-mum coolant temperature attained during steady state operation was 68.3218 °C, while the density and velocity values were 0.9423 kg/cm3 and 1.0241 cm/s, respectively. The minimum values of the temperature, density and velocity were 40.2935 °C, 0.8495 kg/cm3 and 1.0108 cm/s, respectively. The experimental data indicated that the reactor is inherently safe during steady state or normal operations.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76198704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54819
M. Adamu, O. Abass
Parallel machine scheduling problem of maximizing the weighted number of just-in-time jobs was investigated. The problem was NP complete in the strong sense, for which finding an optimal solution had been considered very unlikely. The performances of 4 greedy heuristic algorithms (WO1, WO2, DO1 and DO2) dev-eloped for solving the Pm|| Σ wј xiј problem were analysed. Two approaches adopted for assigning jobs to the machines were according to the earliest start time, and according to difference between latest due date and the job processing time. The time complexity of each algorithm was O(nmlogn). The heuristics WO2 and DO2 were suitable for certain number of machines and number of jobs, while WO1 and DO1 out classed the other two.
{"title":"Parallel machine scheduling to maximize the weighted number of just-in-time jobs","authors":"M. Adamu, O. Abass","doi":"10.4314/JAST.V15I1-2.54819","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54819","url":null,"abstract":"Parallel machine scheduling problem of maximizing the weighted number of just-in-time jobs was investigated. The problem was NP complete in the strong sense, for which finding an optimal solution had been considered very unlikely. The performances of 4 greedy heuristic algorithms (WO1, WO2, DO1 and DO2) dev-eloped for solving the Pm|| Σ wј xiј problem were analysed. Two approaches adopted for assigning jobs to the machines were according to the earliest start time, and according to difference between latest due date and the job processing time. The time complexity of each algorithm was O(nmlogn). The heuristics WO2 and DO2 were suitable for certain number of machines and number of jobs, while WO1 and DO1 out classed the other two.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75793326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54832
R. Ahouansou, E. Sanya, G. Bagan, A. Vianou, D. Hounhouigan
The major difficulty encountered in processing locust beans or nere seeds (Parkia biglobosa) into afitin subsist is the laborious seeds dehusking. Studies were conducted to determine the optimal cooking duration for ensuri-ng the seeds attained 16.14 % (db) water content prior to efficient dehusking. Therefore, the effects of cooking the seeds in water at 102 °C for duration of 1, 2, 3, 4, 5, and 6 hours on the physical characteristics were assess-ed. Depending on the treatment duration, the cooking induced variable modifications in the physical characteri-stics of the seeds. The water content, 1000-seeds mass, and 1000-seeds volume of cooked seeds increased with cooking duration, respectively from 16.14 to 284.62 % (db), 231.66 to 508.33 g and 208 to 482 cm3. Seed poro-sity rose from 35.6 to 42.2 % during the first hour of cooking, but decreased gradually to attain constant value of 41 % for the remaining 5 h. Although the average size of seeds increased marginally, there was corresponding lengthening, indicated by 20.40 % change in thickness, 14.5 % change in length and 13.5 % change in width, which confirmed the remarkable effects of cooking treatment. However, the true and bulk densities decreased respectively from 1110 to 1055 kg/m3 and 715 to 625 kg/m3 as cooking time increased. The data on dimension-al changes (seed length and width) and swelling as function of the cooking time provided parameters for design-ing shelling grids for efficient dehusking.
{"title":"Effects of cooking on some physical characteristics of nere seeds or African locust beans (Parkia biglobosa).","authors":"R. Ahouansou, E. Sanya, G. Bagan, A. Vianou, D. Hounhouigan","doi":"10.4314/JAST.V15I1-2.54832","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54832","url":null,"abstract":"The major difficulty encountered in processing locust beans or nere seeds (Parkia biglobosa) into afitin subsist is the laborious seeds dehusking. Studies were conducted to determine the optimal cooking duration for ensuri-ng the seeds attained 16.14 % (db) water content prior to efficient dehusking. Therefore, the effects of cooking the seeds in water at 102 °C for duration of 1, 2, 3, 4, 5, and 6 hours on the physical characteristics were assess-ed. Depending on the treatment duration, the cooking induced variable modifications in the physical characteri-stics of the seeds. The water content, 1000-seeds mass, and 1000-seeds volume of cooked seeds increased with cooking duration, respectively from 16.14 to 284.62 % (db), 231.66 to 508.33 g and 208 to 482 cm3. Seed poro-sity rose from 35.6 to 42.2 % during the first hour of cooking, but decreased gradually to attain constant value of 41 % for the remaining 5 h. Although the average size of seeds increased marginally, there was corresponding lengthening, indicated by 20.40 % change in thickness, 14.5 % change in length and 13.5 % change in width, which confirmed the remarkable effects of cooking treatment. However, the true and bulk densities decreased respectively from 1110 to 1055 kg/m3 and 715 to 625 kg/m3 as cooking time increased. The data on dimension-al changes (seed length and width) and swelling as function of the cooking time provided parameters for design-ing shelling grids for efficient dehusking.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"88 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75965836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54811
F. Hasford, J. Amuasi, E. Sosu, K. Nani, T. Sackey, M. Boadu, I. K. Wilson, E. Addison
Radioisotopes are used in diagnosing primary and metastatic bone tumours because of the high sensitivity. Diagnosing bone tumours using technetium methylene diphosphonate (Tc-99m MDP) on 9 randomly selected whole-body bone scans have been demonstrated by clinical studies of patients for illustrative review. Upon sati-sfactory testing of the e.cam® Single Photon Emission Computed Tomography at the Nuclear Medicine Depart-ment (Korle-Bu Teaching Hospital), scans of patients provided essential physiologic information about the sites of bone lesions and prognosis as shown by sequential changes in tracer uptake. The bone scintigrams were clas-sified either as normal or pathologic. Of the 197 patients (91 males and 106 females) who underwent radioacti-ve whole-body bone scans in the year 2006, the peak age at bone tumour detection was between 51 and 60 yea-rs. From qualitative analyses of the reported cases, 114 patients were diagnosed with bone tumours, but ~ 17 % were found to be primary, while ~ 83 % were metastatic in nature. The observation confirmed other published data that bone tumours with origin in the cells of bone are not prevalent compared to tumours that metastasize from other parts of the body, such as breast, cervix and prostate. Breast, prostate and cervical cancers contribut-ed respectively to 34 %, 19 % and 18 % of the bone tumour cases, but only 3 % were diagnosed with osteoporo-sis (a relatively rare type of bone disease).
{"title":"Radionuclide Tc-99m MDP imaging for diagnosis of bone tumour at Korle-Bu Teaching Hospital (Ghana) – An Illustrative Review","authors":"F. Hasford, J. Amuasi, E. Sosu, K. Nani, T. Sackey, M. Boadu, I. K. Wilson, E. Addison","doi":"10.4314/JAST.V15I1-2.54811","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54811","url":null,"abstract":"Radioisotopes are used in diagnosing primary and metastatic bone tumours because of the high sensitivity. Diagnosing bone tumours using technetium methylene diphosphonate (Tc-99m MDP) on 9 randomly selected whole-body bone scans have been demonstrated by clinical studies of patients for illustrative review. Upon sati-sfactory testing of the e.cam® Single Photon Emission Computed Tomography at the Nuclear Medicine Depart-ment (Korle-Bu Teaching Hospital), scans of patients provided essential physiologic information about the sites of bone lesions and prognosis as shown by sequential changes in tracer uptake. The bone scintigrams were clas-sified either as normal or pathologic. Of the 197 patients (91 males and 106 females) who underwent radioacti-ve whole-body bone scans in the year 2006, the peak age at bone tumour detection was between 51 and 60 yea-rs. From qualitative analyses of the reported cases, 114 patients were diagnosed with bone tumours, but ~ 17 % were found to be primary, while ~ 83 % were metastatic in nature. The observation confirmed other published data that bone tumours with origin in the cells of bone are not prevalent compared to tumours that metastasize from other parts of the body, such as breast, cervix and prostate. Breast, prostate and cervical cancers contribut-ed respectively to 34 %, 19 % and 18 % of the bone tumour cases, but only 3 % were diagnosed with osteoporo-sis (a relatively rare type of bone disease).","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76700086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54816
A. Obi, C. A. Ngene, I. Aji, O. Ogunleye
A Visual Basic Code “DriveCad” was developed for analysis and design of flat and V-belt drives. The Code was used to solve design problems and the results compared favorably with data generated by manual computat-ions, with variation of less than 1.6 %. DriveCad was used to generate scaled 2-dimensional drawings of pulley and belt assembly at reduced design time with minimal roundoff errors.
{"title":"Computer-Aided design of belt and pulley systems using Visual Basic","authors":"A. Obi, C. A. Ngene, I. Aji, O. Ogunleye","doi":"10.4314/JAST.V15I1-2.54816","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54816","url":null,"abstract":"A Visual Basic Code “DriveCad” was developed for analysis and design of flat and V-belt drives. The Code was used to solve design problems and the results compared favorably with data generated by manual computat-ions, with variation of less than 1.6 %. DriveCad was used to generate scaled 2-dimensional drawings of pulley and belt assembly at reduced design time with minimal roundoff errors.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89825780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54833
N. Njukeng, E. E. Ehabe, G. Nkeng
Natural rubber must be technically specified for various uses. Variability in technological properties of raw nat-ural rubber leads to problems of grading. A study was conducted to establish relationships between physio-logical parameters of latex and technological properties of the raw rubber. The latex samples were analysed by micro-latex diagnosis technique and the relevant technological properties of the processed rubber estimated usi-ng International Standard organization (ISO) procedures. Correlations were found between physiological para-meters and technological properties of processed crumbs; specifically, between the plasticity retention index, Mooney viscosity, Initial Wallace plasticity and inorganic phosphorus, total solid content and sucrose content. The relationships varied with the clones. The best empirical equations fit describing the relationship between physiological parameters of latex and technological properties of the raw rubber were polynomials, while the master equation was a power function with coefficient of determination of 0.84. The values of technological properties of raw rubber could be predicted from the values of some physiological parameters of the latex, and such empirical relationships would assist farmers to forecast values of the technological properties, and modify the properties as required prior to processing.
{"title":"Relationships between physiological parameters of latex and technological properties of processed natural rubber","authors":"N. Njukeng, E. E. Ehabe, G. Nkeng","doi":"10.4314/JAST.V15I1-2.54833","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54833","url":null,"abstract":"Natural rubber must be technically specified for various uses. Variability in technological properties of raw nat-ural rubber leads to problems of grading. A study was conducted to establish relationships between physio-logical parameters of latex and technological properties of the raw rubber. The latex samples were analysed by micro-latex diagnosis technique and the relevant technological properties of the processed rubber estimated usi-ng International Standard organization (ISO) procedures. Correlations were found between physiological para-meters and technological properties of processed crumbs; specifically, between the plasticity retention index, Mooney viscosity, Initial Wallace plasticity and inorganic phosphorus, total solid content and sucrose content. The relationships varied with the clones. The best empirical equations fit describing the relationship between physiological parameters of latex and technological properties of the raw rubber were polynomials, while the master equation was a power function with coefficient of determination of 0.84. The values of technological properties of raw rubber could be predicted from the values of some physiological parameters of the latex, and such empirical relationships would assist farmers to forecast values of the technological properties, and modify the properties as required prior to processing.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74405635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54841
F. Amevenku, F. Attipoe
The economic viability of three aquaculture research technologies was examined to determine the operational profitability in Ghana. The first technology was aimed at producing improved tilapia strain fish seed as input for fish farming, while the second dealt with integrating poultry with fish farming for harnessing synergies of waste recycling and feeding cost reduction. The third technology involved polyculture of fish utilizing the natu-ral feed available to different trophic types of fish within a communal culture environment. While the technolo-gies were considered to be socially desirable that could ensure efficiency in use of resources, screening on-station was germane in technology transfer. Undiscounted profit, rate of return, return on annual operation cost, benefit-cost ratio, return to management, and land were adopted as indicators for assessing viability of the tech-nologies and approaches that could improve profitability. At rate of return of 29.8 %, return on annual operation cost of 43.9 %, benefit-cost ratio of 1.7 and return to management and land of 71.2 %, the communal culture technology involving tilapia-mullet-prawn-catfish gave positive indicator values, but the risk of survival of the species in the culture medium must be minimized. Sensitivity analyses of making gains at the same levels of costs for the other two technologies showed that an eight-fold increase of revenue would be required for the poultry-fish integration model to be viable, while a three-fold increase of revenue would be required for the via-bility of fish seed production. Since the three technologies address different challenges of fish farming, all could be recommended for implementation, with the proviso of maximizing incomes from sales of produce, reducing costs of inputs, and minimizing risks.
{"title":"Economic evaluation of three on-station fish farming technologies","authors":"F. Amevenku, F. Attipoe","doi":"10.4314/JAST.V15I1-2.54841","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54841","url":null,"abstract":"The economic viability of three aquaculture research technologies was examined to determine the operational profitability in Ghana. The first technology was aimed at producing improved tilapia strain fish seed as input for fish farming, while the second dealt with integrating poultry with fish farming for harnessing synergies of waste recycling and feeding cost reduction. The third technology involved polyculture of fish utilizing the natu-ral feed available to different trophic types of fish within a communal culture environment. While the technolo-gies were considered to be socially desirable that could ensure efficiency in use of resources, screening on-station was germane in technology transfer. Undiscounted profit, rate of return, return on annual operation cost, benefit-cost ratio, return to management, and land were adopted as indicators for assessing viability of the tech-nologies and approaches that could improve profitability. At rate of return of 29.8 %, return on annual operation cost of 43.9 %, benefit-cost ratio of 1.7 and return to management and land of 71.2 %, the communal culture technology involving tilapia-mullet-prawn-catfish gave positive indicator values, but the risk of survival of the species in the culture medium must be minimized. Sensitivity analyses of making gains at the same levels of costs for the other two technologies showed that an eight-fold increase of revenue would be required for the poultry-fish integration model to be viable, while a three-fold increase of revenue would be required for the via-bility of fish seed production. Since the three technologies address different challenges of fish farming, all could be recommended for implementation, with the proviso of maximizing incomes from sales of produce, reducing costs of inputs, and minimizing risks.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84206808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54834
S. Mbodji, M. Dieng, B. Mbow, F. I. Barro, G. Sissoko
A three dimensional (3-D) simulated modelling was developed to analyse the excess minority carrier density in the base of a polycrystalline bifacial silicon solar cell. The concept of junction recombination velocity was ado-pted to quantify carrier flow through the junction, and to examine the solar cell diffusion capacitance for three illumination modes (front side, back side and both front and back sides). Plots of diffusion capacitance against grain size, grain boundary recombination velocity, junction recombination velocity and illumination wavelength were used to study the influence of cell parameters on the capacitance. The results indicated that junction and grain boundary recombination velocities played determinant roles, especially, for small grain size and long wav-elength. Hence, high diffusion capacitance was obtained for high junction recombination velocity, large grain size and long wavelength; while small grain size led to increased recombination centers and corresponding decrease in the diffusion capacitance
{"title":"Three dimensional simulated modelling of diffusion capacitance of polycrystalline bifacial silicon solar cell","authors":"S. Mbodji, M. Dieng, B. Mbow, F. I. Barro, G. Sissoko","doi":"10.4314/JAST.V15I1-2.54834","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54834","url":null,"abstract":"A three dimensional (3-D) simulated modelling was developed to analyse the excess minority carrier density in the base of a polycrystalline bifacial silicon solar cell. The concept of junction recombination velocity was ado-pted to quantify carrier flow through the junction, and to examine the solar cell diffusion capacitance for three illumination modes (front side, back side and both front and back sides). Plots of diffusion capacitance against grain size, grain boundary recombination velocity, junction recombination velocity and illumination wavelength were used to study the influence of cell parameters on the capacitance. The results indicated that junction and grain boundary recombination velocities played determinant roles, especially, for small grain size and long wav-elength. Hence, high diffusion capacitance was obtained for high junction recombination velocity, large grain size and long wavelength; while small grain size led to increased recombination centers and corresponding decrease in the diffusion capacitance","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"186 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77500249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54831
M. Benachour, A. Hadjoui, M. Benguediab, N. Benachour
Fatigue life and fatigue crack growth rate are controlled by stress ratio, stress level, orientation of crack, temper-ature, residual stress, corrosion, etc. The effects of residual stress on fatigue crack growth in aluminium (Al) alloy 2024-T351 by Mode I crack were investigated by applying constant amplitude cycles based on maximum stress intensity factor failure criteria. The residual stress fields induced by cold expansion were imposed on the specimen with double through crack at hole by numerical experimentation. The fatigue crack growth tests were performed in transverse-longitudinal orientation using NASGRO model. The effects of stress ratio and different levels of residual stress fields on fatigue life and fatigue crack growth rates were analyzed. The results showed that compressive residual stress has significant effect on fatigue behavior of Al alloy 2024-T351.
{"title":"Effect of residual stress induced by cold expansion on fatigue crack growth of Aluminium alloy 2024-T351","authors":"M. Benachour, A. Hadjoui, M. Benguediab, N. Benachour","doi":"10.4314/JAST.V15I1-2.54831","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54831","url":null,"abstract":"Fatigue life and fatigue crack growth rate are controlled by stress ratio, stress level, orientation of crack, temper-ature, residual stress, corrosion, etc. The effects of residual stress on fatigue crack growth in aluminium (Al) alloy 2024-T351 by Mode I crack were investigated by applying constant amplitude cycles based on maximum stress intensity factor failure criteria. The residual stress fields induced by cold expansion were imposed on the specimen with double through crack at hole by numerical experimentation. The fatigue crack growth tests were performed in transverse-longitudinal orientation using NASGRO model. The effects of stress ratio and different levels of residual stress fields on fatigue life and fatigue crack growth rates were analyzed. The results showed that compressive residual stress has significant effect on fatigue behavior of Al alloy 2024-T351.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81382393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-27DOI: 10.4314/JAST.V15I1-2.54820
Pb Osofisan, A. Orji
Fuzzy logic controller (FLC) for crude oil flow rates and tank levels was designed for monitoring flow and tank level management at Escravos Tank Farm in Nigeria. The fuzzy control system incorporated essence of expert knowledge required to handle the tasks. Proportional Integral Derivative (PID) control of crude flow rates and levels was also investigated, and the performance compared with the FLC and hybrid FLC/PID control by using rise time and settling time as system parameters. The FLC provided the best system management when compar-ed with PID and FLC/PID controls.
{"title":"Fuzzy logic controller for crude oil levels at Escravos Tank Farm","authors":"Pb Osofisan, A. Orji","doi":"10.4314/JAST.V15I1-2.54820","DOIUrl":"https://doi.org/10.4314/JAST.V15I1-2.54820","url":null,"abstract":"Fuzzy logic controller (FLC) for crude oil flow rates and tank levels was designed for monitoring flow and tank level management at Escravos Tank Farm in Nigeria. The fuzzy control system incorporated essence of expert knowledge required to handle the tasks. Proportional Integral Derivative (PID) control of crude flow rates and levels was also investigated, and the performance compared with the FLC and hybrid FLC/PID control by using rise time and settling time as system parameters. The FLC provided the best system management when compar-ed with PID and FLC/PID controls.","PeriodicalId":9207,"journal":{"name":"British Journal of Applied Science and Technology","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88268227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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