In this study, control factors which included aspect ratio of fibres, volume fraction of fibres and fibres orientation were the focus for determining the optimum tensile strengths of coir fibres reinforced polyester r...In this study, control factors which included aspect ratio of fibres, volume fraction of fibres and fibres orientation were the focus for determining the optimum tensile strengths of coir fibres reinforced polyester resin composites. After using Archimedes principle to determine the volume fraction of fibres, tensile test was conducted on the samples of treated and untreated coir fibres reinforced polyester resin composites, respectively. For the optimum properties to be obtained, a Universal Testing Machine-TUE-C-100 was used for the conducted tensile tests which established the levels of control factors settings for quality characteristics needed to optimize the mechanical properties being investigated. Applying Taguchi robust design technique for the greater-the-better, the highest signal-to-noise ratio (S/N ratio) for the quality characteristics being investigated was obtained employing Minitab 16 software. The optimum values of the control factors were established for treated coir fibres reinforced polyester resin composites and untreated coir fibres reinforced polyester resin composites. The treated coir fibres reinforced polyester matrix composite has the optimum tensile strength of 42.7 N/mm2 while the untreated coir fibres reinforced matrix composite has the optimum tensile strength of 21.9 N/mm2. The reinforcement combinations of control factors contribute greatly to the tensile properties, and the treated coir fibres reinforced polyester composites are stronger in tension than the untreated coir fibres reinforced polyester composites.展开更多
Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of component...Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of components. In this work, the fracture behavior of Polypropylene/Talc composites was studied. From the results of the tensile and flexural tests conducted on the composite, scatter diagrams were made using Microsoft Excel to evaluate and show the effect of the addition of the talc filler as it affects the tensile strength, percentage elongation at break, flexural strength and modulus. In order to give additional analysis, the talc filler content effect was presented mathematically to further describe explicitly the various equations associated with each scatter diagram earlier developed using Microsoft Excel. The mathematical expression developed shows the actual talc filler content on the fracture mechanical properties of the sample composite.展开更多
This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specim...This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specimens were machined to a precise gauge length and diameter and exposed to various cycles of heat at each temperature. A fatigue test was also performed with the use of Avery Dennison and bending stress was obtained using the curve supplied with the machine. The results from the machine were converted to Mega Pascal (MPa) and the values used to plot S-N curves and fatigue resistance for the specimens at various cycles and different temperatures were established.展开更多
Kaolin was modified using a chemical complex of hydrazine hydrate and oleochemical sodium salts derived from rubber seed oil (SRSO) and tea seed oil (STSO) respectively. Characterization of the pristine kaolin and the...Kaolin was modified using a chemical complex of hydrazine hydrate and oleochemical sodium salts derived from rubber seed oil (SRSO) and tea seed oil (STSO) respectively. Characterization of the pristine kaolin and the modified kaolins were performed using Scanning Electron Microscopy (SEM), Simultaneous Thermogravimetric/Differential Thermal Analysis (TG/DTA) and UV Spectrophotometry. TG/DTA revealed that the incorporation of the oleochemical salts enhanced thermal decomposition of kaolin into metakaolin. Ultraviolet spectrophotometric studies conducted on the modified kaolin show for the first time that the SRSO-modified kaolin and STSO-modified kaolin have a peak absorbance wavelengths of 312.72 nm and 314.26 nm respectively. This shows that the modified kaolin is a promising candidate for sunscreen applications.展开更多
Studies were carried out to investigate the outdoor air pollution levels in vehicular traffic junctions in the major cities of Nsukka, Enugu and semi-urban area of Awgu all in Enugu State, Nigeria using standard analy...Studies were carried out to investigate the outdoor air pollution levels in vehicular traffic junctions in the major cities of Nsukka, Enugu and semi-urban area of Awgu all in Enugu State, Nigeria using standard analytical procedures. PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;"> was collected using Envirotech air sampler, APM 550 and analyzed gravimetrically. Other determined air pollutant gases such as SO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, NO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, O</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> and CO were analyzed using colorimetric techniques. The mean hourly traffic density in the vehicular traffic junctions in Nsukka metropolis, Enugu metropolis and Awgu w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> 2015, 2873 and 587 respectively. The mean range of values of PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;">, NO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, SO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, O</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> and CO in vehicular traffic junctions within the investigated environments w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> 1.67 - 12.16 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 3.72 - 23.83 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 2.96 - 30.09 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 5.45 - 66.54 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;"> and 1.18 - 15.17 ppm respectively. The mean levels of the determined air pollutants in the air around vehicular traffic junctions in Nsukka metropolis, Enugu metropolis and Awgu semi-urban area differed significantly. The mean levels of PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;">, and CO in the air around vehicular traffic junctions in Enugu metropolis and CO in the air around traffic junctions in Nsukka metropolis were above the recommended permissible limits. Traffic density was therefore seen as the single most important factor contributing to the varying air pollution levels observed in the investigated environments.展开更多
文摘In this study, control factors which included aspect ratio of fibres, volume fraction of fibres and fibres orientation were the focus for determining the optimum tensile strengths of coir fibres reinforced polyester resin composites. After using Archimedes principle to determine the volume fraction of fibres, tensile test was conducted on the samples of treated and untreated coir fibres reinforced polyester resin composites, respectively. For the optimum properties to be obtained, a Universal Testing Machine-TUE-C-100 was used for the conducted tensile tests which established the levels of control factors settings for quality characteristics needed to optimize the mechanical properties being investigated. Applying Taguchi robust design technique for the greater-the-better, the highest signal-to-noise ratio (S/N ratio) for the quality characteristics being investigated was obtained employing Minitab 16 software. The optimum values of the control factors were established for treated coir fibres reinforced polyester resin composites and untreated coir fibres reinforced polyester resin composites. The treated coir fibres reinforced polyester matrix composite has the optimum tensile strength of 42.7 N/mm2 while the untreated coir fibres reinforced matrix composite has the optimum tensile strength of 21.9 N/mm2. The reinforcement combinations of control factors contribute greatly to the tensile properties, and the treated coir fibres reinforced polyester composites are stronger in tension than the untreated coir fibres reinforced polyester composites.
文摘Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of components. In this work, the fracture behavior of Polypropylene/Talc composites was studied. From the results of the tensile and flexural tests conducted on the composite, scatter diagrams were made using Microsoft Excel to evaluate and show the effect of the addition of the talc filler as it affects the tensile strength, percentage elongation at break, flexural strength and modulus. In order to give additional analysis, the talc filler content effect was presented mathematically to further describe explicitly the various equations associated with each scatter diagram earlier developed using Microsoft Excel. The mathematical expression developed shows the actual talc filler content on the fracture mechanical properties of the sample composite.
文摘This paper examines the behavior of low carbon steels subjected to a frequency thermal cycling test. A compositional analysis was performed to ascertain the percentage of carbon in the asreceived materials. The specimens were machined to a precise gauge length and diameter and exposed to various cycles of heat at each temperature. A fatigue test was also performed with the use of Avery Dennison and bending stress was obtained using the curve supplied with the machine. The results from the machine were converted to Mega Pascal (MPa) and the values used to plot S-N curves and fatigue resistance for the specimens at various cycles and different temperatures were established.
文摘Kaolin was modified using a chemical complex of hydrazine hydrate and oleochemical sodium salts derived from rubber seed oil (SRSO) and tea seed oil (STSO) respectively. Characterization of the pristine kaolin and the modified kaolins were performed using Scanning Electron Microscopy (SEM), Simultaneous Thermogravimetric/Differential Thermal Analysis (TG/DTA) and UV Spectrophotometry. TG/DTA revealed that the incorporation of the oleochemical salts enhanced thermal decomposition of kaolin into metakaolin. Ultraviolet spectrophotometric studies conducted on the modified kaolin show for the first time that the SRSO-modified kaolin and STSO-modified kaolin have a peak absorbance wavelengths of 312.72 nm and 314.26 nm respectively. This shows that the modified kaolin is a promising candidate for sunscreen applications.
文摘Studies were carried out to investigate the outdoor air pollution levels in vehicular traffic junctions in the major cities of Nsukka, Enugu and semi-urban area of Awgu all in Enugu State, Nigeria using standard analytical procedures. PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;"> was collected using Envirotech air sampler, APM 550 and analyzed gravimetrically. Other determined air pollutant gases such as SO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, NO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, O</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> and CO were analyzed using colorimetric techniques. The mean hourly traffic density in the vehicular traffic junctions in Nsukka metropolis, Enugu metropolis and Awgu w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> 2015, 2873 and 587 respectively. The mean range of values of PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;">, NO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, SO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, O</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;"> and CO in vehicular traffic junctions within the investigated environments w</span></span><span style="font-family:Verdana;">ere</span><span style="font-family:""><span style="font-family:Verdana;"> 1.67 - 12.16 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 3.72 - 23.83 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 2.96 - 30.09 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, 5.45 - 66.54 μg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;"> and 1.18 - 15.17 ppm respectively. The mean levels of the determined air pollutants in the air around vehicular traffic junctions in Nsukka metropolis, Enugu metropolis and Awgu semi-urban area differed significantly. The mean levels of PM</span><sub><span style="font-family:Verdana;">2.5</span></sub><span style="font-family:Verdana;">, and CO in the air around vehicular traffic junctions in Enugu metropolis and CO in the air around traffic junctions in Nsukka metropolis were above the recommended permissible limits. Traffic density was therefore seen as the single most important factor contributing to the varying air pollution levels observed in the investigated environments.
