Modeling extreme stochastic phenomena associated with catastrophic temperatures, heat waves, earthquakes and destructive floods is an aspect of proactive mitigation of risk. Hydrologists, reliability engineers, meteorologist and researchers among other stakeholders are faced with the challenges of providing adequate model for fitting real life datasets from the extreme natural hazardous occurrences in our environment. Convoluted distributions (CD) and generalized extreme value (GEV) distribution for r- largest order statistics (r-LOS) have been some of the prominent existing techniques for modeling the extreme events. This study explored the properties of order statistics from the convoluted distribution as alternative procedure for analyzing the extreme maximum with the aim of obtaining superior modeling fit compared to some other existing techniques. The new procedure called MAXOS-G employed the potential properties of the Maximum Order Statistics (MAXOS) and the flexibilities of convoluted distributions where G is taken to beWeibull-Exponential Pareto (WEP) and the New Kumaraswamy-Weibull (NKwei) distributions. The maximum order statistics of the WEP distribution (MAXOS-WEP) and NKwei distribution (MAXOS-NKwei) was derived and applied to three datasets consisting of annual maximum flood discharges, annual maximum precipitation and annual maximum one-day rainfall. Some properties of the MAXOS-WEP was investigated including the moment, mean, variance, skewness, and kurtosis. Characterization of WEP distribution by the L-moment of maximum order statistics was presented and coefficient of L-variation, L-skewness and L-kurtosis were derived. The results from the application to three datasets using R-software justified the importance of this new procedure for modeling the maximum events. The MAXOS-NKwei and MAXOS-WEP models provide superior goodness-of-fit to the datasets than the WEP and NKwei distributions and better than some previously proposed convoluted distributions for modeling the datasets.
{"title":"Modeling Extreme Stochastic Variations using the Maximum Order Statistics of Convoluted Distributions","authors":"A. O. Adeyemi, I. Adeleke, E. Akarawak","doi":"10.46481/jnsps.2023.994","DOIUrl":"https://doi.org/10.46481/jnsps.2023.994","url":null,"abstract":"Modeling extreme stochastic phenomena associated with catastrophic temperatures, heat waves, earthquakes and destructive floods is an aspect of proactive mitigation of risk. Hydrologists, reliability engineers, meteorologist and researchers among other stakeholders are faced with the challenges of providing adequate model for fitting real life datasets from the extreme natural hazardous occurrences in our environment. Convoluted distributions (CD) and generalized extreme value (GEV) distribution for r- largest order statistics (r-LOS) have been some of the prominent existing techniques for modeling the extreme events. This study explored the properties of order statistics from the convoluted distribution as alternative procedure for analyzing the extreme maximum with the aim of obtaining superior modeling fit compared to some other existing techniques. The new procedure called MAXOS-G employed the potential properties of the Maximum Order Statistics (MAXOS) and the flexibilities of convoluted distributions where G is taken to beWeibull-Exponential Pareto (WEP) and the New Kumaraswamy-Weibull (NKwei) distributions. The maximum order statistics of the WEP distribution (MAXOS-WEP) and NKwei distribution (MAXOS-NKwei) was derived and applied to three datasets consisting of annual maximum flood discharges, annual maximum precipitation and annual maximum one-day rainfall. Some properties of the MAXOS-WEP was investigated including the moment, mean, variance, skewness, and kurtosis. Characterization of WEP distribution by the L-moment of maximum order statistics was presented and coefficient of L-variation, L-skewness and L-kurtosis were derived. The results from the application to three datasets using R-software justified the importance of this new procedure for modeling the maximum events. The MAXOS-NKwei and MAXOS-WEP models provide superior goodness-of-fit to the datasets than the WEP and NKwei distributions and better than some previously proposed convoluted distributions for modeling the datasets.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131709274","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}
An investigation of the heavy metals in the bed sediment of Asunle stream was carried out to assess how seriously the sediment is polluted using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The potential health risk assessment was calculated for a lifetime exposure (ingestion) based on the United State Environmental Protection Agency (USEPA) models to determine the carcinogenic and noncarcinogenic risks for children and adults. The range of values (mg/kg) of heavy metals in bed sediment were: Fe (2850 – 7260), Mn (58 – 209), Co (0.7 – 33), Ti (21.6 – 67), Ba (1.61 – 9.81), Zn (7.5 – 79), Cu (5.6 – 25), As (8 – 137), Al (273 – 2160), Y (24 – 49), and Sr (0.10 – 5.3). As and Sr, values were below the background values for typical soil. The health risk assessment of heavy metals in the bed sediments revealed that carcinogenic risk was almost insignificant while the non-carcinogenic risk was significant since their values were above the recommended minimal risk level. The results also revealed that children are more vulnerable to hazards than adults. The chronic hazard quotient index for exposure to these metals through ingestion exceeded the acceptable USEPA value of 1.0.
{"title":"Health Risk Assessment of Heavy Metals in Sediment of Tropical Freshwater Stream","authors":"G. Olutona","doi":"10.46481/jnsps.2023.983","DOIUrl":"https://doi.org/10.46481/jnsps.2023.983","url":null,"abstract":"An investigation of the heavy metals in the bed sediment of Asunle stream was carried out to assess how seriously the sediment is polluted using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The potential health risk assessment was calculated for a lifetime exposure (ingestion) based on the United State Environmental Protection Agency (USEPA) models to determine the carcinogenic and noncarcinogenic risks for children and adults. The range of values (mg/kg) of heavy metals in bed sediment were: Fe (2850 – 7260), Mn (58 – 209), Co (0.7 – 33), Ti (21.6 – 67), Ba (1.61 – 9.81), Zn (7.5 – 79), Cu (5.6 – 25), As (8 – 137), Al (273 – 2160), Y (24 – 49), and Sr (0.10 – 5.3). As and Sr, values were below the background values for typical soil. The health risk assessment of heavy metals in the bed sediments revealed that carcinogenic risk was almost insignificant while the non-carcinogenic risk was significant since their values were above the recommended minimal risk level. The results also revealed that children are more vulnerable to hazards than adults. The chronic hazard quotient index for exposure to these metals through ingestion exceeded the acceptable USEPA value of 1.0.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"466 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122951809","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}
Syenites are relatively rare within the Nigerian Basement Complex. As a result of their rarity, these rocks have been given less research attention over time and are consequently poorly understood. The syenitic rocks at Igarra were studied to ascertain their tectonic evolution using geochemistry. Sampling was carried out using the survey-type geological field mapping approach. A total of 10 samples of syenitic rocks were collected for laboratory analyses. Compositionally, the rocks are intermediate with regards to SiO2 content (58.02% – 60.58%), having Al2O3 and alkali (Na2O + K2O) compositional ranges of 15.34% – 15.52% and 8.99% – 9.7% respectively. The sampled rocks are similar and consistent in their trace and rare earth elements concentrations (the only exception being Zr with values ranging from 4 ppm to 79 ppm). The rocks are relatively enriched in Ba, K, TI, and Sr but depleted in Tc, Nb, U, Hf, Yb, Te and Ta. The syenites also show fairly high ratios of Rb/Nb and Rb/Sr with mean values of 488.627 and 0.171 respectively. As seen from the geochemical analyses, the syenites around Igarra are high-K calcalkaline, alkalic to alkalic-calcic. The rocks are peraluminous in character as shown by the bivariate plot of A/NK vs. A/CNK. Sedimentary protolith with continental crustal parent magma is inferred for these rocks. The similarity and consistency of the trends of major, trace and rare earth elements is indicative of cogenetic origin for the rocks. The geochemistry and discrimination plots for the rocks indicate geodynamic setting ranging from orogenic to post-orogenic. A volcanic arc geotectonic setting is interpreted for the Igarra syenites, with magma emplacement and evolution thought to have been initiated during the late stages of the Pan-African reactivation and continued into post-orogenic times.
{"title":"Tectonic Setting of the Syenite Around Igarra, Southwestern Nigeria: Constraints from Geochemistry","authors":"F. Ugbe, O. E. Ominigbo, A. Akano","doi":"10.46481/jnsps.2023.999","DOIUrl":"https://doi.org/10.46481/jnsps.2023.999","url":null,"abstract":"Syenites are relatively rare within the Nigerian Basement Complex. As a result of their rarity, these rocks have been given less research attention over time and are consequently poorly understood. The syenitic rocks at Igarra were studied to ascertain their tectonic evolution using geochemistry. Sampling was carried out using the survey-type geological field mapping approach. A total of 10 samples of syenitic rocks were collected for laboratory analyses. Compositionally, the rocks are intermediate with regards to SiO2 content (58.02% – 60.58%), having Al2O3 and alkali (Na2O + K2O) compositional ranges of 15.34% – 15.52% and 8.99% – 9.7% respectively. The sampled rocks are similar and consistent in their trace and rare earth elements concentrations (the only exception being Zr with values ranging from 4 ppm to 79 ppm). The rocks are relatively enriched in Ba, K, TI, and Sr but depleted in Tc, Nb, U, Hf, Yb, Te and Ta. The syenites also show fairly high ratios of Rb/Nb and Rb/Sr with mean values of 488.627 and 0.171 respectively. As seen from the geochemical analyses, the syenites around Igarra are high-K calcalkaline, alkalic to alkalic-calcic. The rocks are peraluminous in character as shown by the bivariate plot of A/NK vs. A/CNK. Sedimentary protolith with continental crustal parent magma is inferred for these rocks. The similarity and consistency of the trends of major, trace and rare earth elements is indicative of cogenetic origin for the rocks. The geochemistry and discrimination plots for the rocks indicate geodynamic setting ranging from orogenic to post-orogenic. A volcanic arc geotectonic setting is interpreted for the Igarra syenites, with magma emplacement and evolution thought to have been initiated during the late stages of the Pan-African reactivation and continued into post-orogenic times.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121925950","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 : 2023-02-24DOI: 10.46481/jnsps.2023.1244
C. Falk, Tarek El Ghayed, Ron van de Sand, J. Reiff-Stephan
Refrigeration applications consume a significant share of total electricity demand, with a high indirect impact on global warming through greenhouse gas emissions. Modern technology can help reduce the high power consumption and optimize the cooling control. This paper presents a case study of machine-learning for controlling a commercial refrigeration system. In particular, an approach to reinforcement learning is implemented, trained and validated utilizing a model of a real chiller plant. The reinforcement-learning controller learns to operate the plant based on its interactions with the modeled environment. The validation demonstrates the functionality of the approach, saving around 7% of the energy demand of the reference control. Limitations of the approach were identified in the discretization of the real environment and further model-based simplifications and should be addressed in future research.
{"title":"A Data-Driven Approach Towards the Application of Reinforcement Learning Based HVAC Control","authors":"C. Falk, Tarek El Ghayed, Ron van de Sand, J. Reiff-Stephan","doi":"10.46481/jnsps.2023.1244","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1244","url":null,"abstract":"Refrigeration applications consume a significant share of total electricity demand, with a high indirect impact on global warming through greenhouse gas emissions. Modern technology can help reduce the high power consumption and optimize the cooling control. This paper presents a case study of machine-learning for controlling a commercial refrigeration system. In particular, an approach to reinforcement learning is implemented, trained and validated utilizing a model of a real chiller plant. The reinforcement-learning controller learns to operate the plant based on its interactions with the modeled environment. The validation demonstrates the functionality of the approach, saving around 7% of the energy demand of the reference control. Limitations of the approach were identified in the discretization of the real environment and further model-based simplifications and should be addressed in future research.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"176 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120912119","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 : 2023-02-24DOI: 10.46481/jnsps.2023.1103
A. Disu, S. Salawu
An investigation of magneto-hyperbolic tangent fluid motion through a porous sheet which stretches vertically upward with temperature-reliant thermal conductivity is scrutinized in this study. The current model characterizes thermal radiation and the impact of internal heat source in the heat equation plus velocity and thermal slipperation at the wall. The translation of the transport equations is carried out via the scaling Lie group technique and the resultant equations are numerically tackled via shooting scheme jointly with Fehlberg integration Runge-Kutta scheme. The results are publicized through various graphs to showcase the reactions of the fluid terms on the thermal and velocity fields. From the investigations, it is found that rising values of the material Weissenberg number, slip and suction terms damped the hydrodynamic boundary film whereas the heat field is prompted directly with thermal conductivity.
{"title":"Thermal distribution of magneto-tangent hyperbolic flowing fluid over a porous moving sheet: A Lie group analysis","authors":"A. Disu, S. Salawu","doi":"10.46481/jnsps.2023.1103","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1103","url":null,"abstract":"An investigation of magneto-hyperbolic tangent fluid motion through a porous sheet which stretches vertically upward with temperature-reliant thermal conductivity is scrutinized in this study. The current model characterizes thermal radiation and the impact of internal heat source in the heat equation plus velocity and thermal slipperation at the wall. The translation of the transport equations is carried out via the scaling Lie group technique and the resultant equations are numerically tackled via shooting scheme jointly with Fehlberg integration Runge-Kutta scheme. The results are publicized through various graphs to showcase the reactions of the fluid terms on the thermal and velocity fields. From the investigations, it is found that rising values of the material Weissenberg number, slip and suction terms damped the hydrodynamic boundary film whereas the heat field is prompted directly with thermal conductivity.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128246675","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 : 2023-02-24DOI: 10.46481/jnsps.2023.1043
S. Shaibu, E. Inam, E. Moses, U. Ofon, O. Fatunla, C. Obadimu, Nnamso Ibuotenang, Nnanake-Abasi O. Offiong, V. Ekpo, Tijesu Adeoye, Edidiong Udokang, D. Fapojuwo
Nanoremediation approaches have been applied to remove oil from surface and ground water as oil spills have been found to have long-term negative consequences for the ecosystem. Nanoremediation via the nanosorption mechanism of different environmental matrices in the world at large is at its formative stages despite the alarming and extensive prevalence of petroleum related environmental pollution. Over 9 million barrels of oil have been leaked in the last five decades, making that ecosystem one of the most deteriorated by oil exploration and extraction activities. The goal of this research is to assess the current status, trends, and future prospects of the nanosorption of surface and ground water in oil spill regions. High surface area of nanomaterials, wide spectrum of treatable contaminants, non-generation of intermediate or secondary products, as well as speed and extent of contaminant destruction give nanoremediation a superior comparative edge over other treatment technologies. Notably, the remediation efficiency of a cleanup is highly dependent on the type of material and treatment routes employed. It is imperative to employ a concerted and practical approach to the development of nanotechnology to combat the bedeviling oil pollution challenges faced in oil producing counties.
{"title":"Prospects of nanosorption and photocatalysis in remediation of oil spills","authors":"S. Shaibu, E. Inam, E. Moses, U. Ofon, O. Fatunla, C. Obadimu, Nnamso Ibuotenang, Nnanake-Abasi O. Offiong, V. Ekpo, Tijesu Adeoye, Edidiong Udokang, D. Fapojuwo","doi":"10.46481/jnsps.2023.1043","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1043","url":null,"abstract":"Nanoremediation approaches have been applied to remove oil from surface and ground water as oil spills have been found to have long-term negative consequences for the ecosystem. Nanoremediation via the nanosorption mechanism of different environmental matrices in the world at large is at its formative stages despite the alarming and extensive prevalence of petroleum related environmental pollution. Over 9 million barrels of oil have been leaked in the last five decades, making that ecosystem one of the most deteriorated by oil exploration and extraction activities. The goal of this research is to assess the current status, trends, and future prospects of the nanosorption of surface and ground water in oil spill regions. High surface area of nanomaterials, wide spectrum of treatable contaminants, non-generation of intermediate or secondary products, as well as speed and extent of contaminant destruction give nanoremediation a superior comparative edge over other treatment technologies. Notably, the remediation efficiency of a cleanup is highly dependent on the type of material and treatment routes employed. It is imperative to employ a concerted and practical approach to the development of nanotechnology to combat the bedeviling oil pollution challenges faced in oil producing counties.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134040054","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 : 2023-02-24DOI: 10.46481/jnsps.2023.1112
Dlal Bashir, H. Kamarulhaili, O. Babarinsa
Quadrant Interlocking Factorization (QIF), an alternative to LU factorization, is suitable for factorizing invertible matrix A such that det(A) , 0. The QIF, with its application in parallel computing, is the most efficient matrix factorization technique yet underutilized. The two forms of QIF among others, which are not only similar in algorithm but also in computation, are WZ factorization and WH factorization yet differs in applications and properties. This review discusses both the old form of QIF, called WZ factorization, and the latest form of QIF, called WH factorization, with an example and open questions to further the studies between the two factorization techniques.
{"title":"A Review on Quadrant Interlocking Factorization: WZ andWH Factorization","authors":"Dlal Bashir, H. Kamarulhaili, O. Babarinsa","doi":"10.46481/jnsps.2023.1112","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1112","url":null,"abstract":"Quadrant Interlocking Factorization (QIF), an alternative to LU factorization, is suitable for factorizing invertible matrix A such that det(A) , 0. The QIF, with its application in parallel computing, is the most efficient matrix factorization technique yet underutilized. The two forms of QIF among others, which are not only similar in algorithm but also in computation, are WZ factorization and WH factorization yet differs in applications and properties. This review discusses both the old form of QIF, called WZ factorization, and the latest form of QIF, called WH factorization, with an example and open questions to further the studies between the two factorization techniques.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115119550","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}
With the well-established correlation between the relative stabilities of isomers and their interstellar abundances coupled with the prevalence of isomeric species among the interstellar molecular species, isomerization remains a plausible formation route for isomers in the interstellar medium. The present work reports an extensive investigation of the isomerization energies of 246 molecular species from 65 isomeric groups using the Gaussian-4 theory composite method with atoms ranging from 3 to 12. From the results, the high abundances of the most stable isomers coupled with the energy sources in interstellar medium drive the isomerization process even for barriers as high as 67.4 kcal/mol. Specifically, the cyanides and their corresponding isocyanides pairs appear to be effectively synthesized via this process. The following potential interstellar molecules; CNC, NCCN, c-C5H, methylene ketene, methyl Ketene, CH3SCH3, C5O, 1,1-ethanediol, propanoic acid, propan-2-ol, and propanol are identified and discussed. The study further reaffirms the importance of thermodynamics in interstellar formation processes on a larger scale and accounts for the known isomeric species. In all the isomeric groups, isomerization appears to be an effective route for the formation of the less stable isomers (which are probably less abundant) from the most stable ones that are perhaps more abundant.
{"title":"Benchmark Studies on the Isomerization Enthalpies for Interstellar Molecular Species","authors":"E. Etim","doi":"10.46481/jnsps.2023.527","DOIUrl":"https://doi.org/10.46481/jnsps.2023.527","url":null,"abstract":"With the well-established correlation between the relative stabilities of isomers and their interstellar abundances coupled with the prevalence of isomeric species among the interstellar molecular species, isomerization remains a plausible formation route for isomers in the interstellar medium. The present work reports an extensive investigation of the isomerization energies of 246 molecular species from 65 isomeric groups using the Gaussian-4 theory composite method with atoms ranging from 3 to 12. From the results, the high abundances of the most stable isomers coupled with the energy sources in interstellar medium drive the isomerization process even for barriers as high as 67.4 kcal/mol. Specifically, the cyanides and their corresponding isocyanides pairs appear to be effectively synthesized via this process. The following potential interstellar molecules; CNC, NCCN, c-C5H, methylene ketene, methyl Ketene, CH3SCH3, C5O, 1,1-ethanediol, propanoic acid, propan-2-ol, and propanol are identified and discussed. The study further reaffirms the importance of thermodynamics in interstellar formation processes on a larger scale and accounts for the known isomeric species. In all the isomeric groups, isomerization appears to be an effective route for the formation of the less stable isomers (which are probably less abundant) from the most stable ones that are perhaps more abundant.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132285885","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 : 2023-02-04DOI: 10.46481/jnsps.2023.1109
L. Afolagboye, Zaccheaus Olajide Arije, A. O. Talabi, O. O. Owoyemi
The properties of residual soils, according to literature, are sensitive to the pre-test drying method given to the sample prior to testing. Similarly, residual soils such as laterites/lateritic soils are formed under various climatic conditions, hence they show different degrees of sensitivity to pretest drying method. This work is therefore carried out to elucidate the influence of pre-test drying temperature or method on the properties of three lateritic soils that developed over three different Pre-Cambrian basement complex rocks from Ado-Ekiti, SW, Nigeria. The soils were subjected to three pre-test drying temperature before conducting laboratory tests. The pre-test drying temperature considered in this study include air-drying, oven-drying at 60° C, and oven-drying at 110° C. Pre-test drying at 60° and 110° C caused particle aggregation (which reduced the soil surface are) and loss of cohesion. Consequently, this reduced the specific gravity, optimum moisture content, clay content, consistency limits, and unconfined compressive strength of the lateritic soils. The maximum dry density and sand content increased as the pre-test drying temperature increases. The pre-test drying temperature did not significantly change the plasticity classification of the soils, however, at higher pre-test temperature the soils become less plastic. The free swell index of the lateritic soils increased with increasing pre-test drying temperature (up to 60° C) before decreasing when the temperature rose to 110° C. This study has revealed the effect pre-test drying temperature may have on the properties of lateritic soils and these may produce soil properties that may not likely indicate the actual field performance of the tested soils.
{"title":"Effect of Pre-Test Drying Temperature on the Properties of Lateritic Soils.","authors":"L. Afolagboye, Zaccheaus Olajide Arije, A. O. Talabi, O. O. Owoyemi","doi":"10.46481/jnsps.2023.1109","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1109","url":null,"abstract":"The properties of residual soils, according to literature, are sensitive to the pre-test drying method given to the sample prior to testing. Similarly, residual soils such as laterites/lateritic soils are formed under various climatic conditions, hence they show different degrees of sensitivity to pretest drying method. This work is therefore carried out to elucidate the influence of pre-test drying temperature or method on the properties of three lateritic soils that developed over three different Pre-Cambrian basement complex rocks from Ado-Ekiti, SW, Nigeria. The soils were subjected to three pre-test drying temperature before conducting laboratory tests. The pre-test drying temperature considered in this study include air-drying, oven-drying at 60° C, and oven-drying at 110° C. Pre-test drying at 60° and 110° C caused particle aggregation (which reduced the soil surface are) and loss of cohesion. Consequently, this reduced the specific gravity, optimum moisture content, clay content, consistency limits, and unconfined compressive strength of the lateritic soils. The maximum dry density and sand content increased as the pre-test drying temperature increases. The pre-test drying temperature did not significantly change the plasticity classification of the soils, however, at higher pre-test temperature the soils become less plastic. The free swell index of the lateritic soils increased with increasing pre-test drying temperature (up to 60° C) before decreasing when the temperature rose to 110° C. This study has revealed the effect pre-test drying temperature may have on the properties of lateritic soils and these may produce soil properties that may not likely indicate the actual field performance of the tested soils.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121747438","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 : 2023-02-04DOI: 10.46481/jnsps.2023.1137
O. Ibidoja, Fam Pei Shan, Mukhtar, J. Sulaiman, Majid Khan Majahar Ali
A common problem in regression analysis using ordinary least squares (OLS) is the effect of outliers or contaminated data on the estimates of the parameters. A robust method that is not sensitive to outliers and can handle contaminated data is needed. In this study, the objective is to determine the significant parameters that determine the moisture content of the seaweed after drying and develop a hybrid model to reduce the outliers. The data were collected with sensors from the v-Groove Hybrid Solar Drier (v-GHSD) at Semporna, South-Eastern Coast of Sabah, Malaysia. After the second order interaction, we have 435 drying parameters, each parameter has 1914 observations. First, we used four machine learning algorithms, such as random forest, support vector machine, bagging and boosting to determine the significant parameters by selecting 15, 25, 35 and 45 parameters. Second, we developed the hybrid model using robust methods such as M. Bi-Square, M. Hampel and M. Huber. The results show that there is a significant improvement in the reduction of the number of outliers and better prediction using hybrid model for the contaminated seaweed big data. For the highest variable importance of 45 significant drying parameters of seaweed, the hybrid model bagging M Bi-square performs better because it has the lowest percentage of outliers of 4.08 %.
{"title":"Robust M-estimators and Machine Learning Algorithms for Improving the Predictive Accuracy of Seaweed Contaminated Big Data","authors":"O. Ibidoja, Fam Pei Shan, Mukhtar, J. Sulaiman, Majid Khan Majahar Ali","doi":"10.46481/jnsps.2023.1137","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1137","url":null,"abstract":"A common problem in regression analysis using ordinary least squares (OLS) is the effect of outliers or contaminated data on the estimates of the parameters. A robust method that is not sensitive to outliers and can handle contaminated data is needed. In this study, the objective is to determine the significant parameters that determine the moisture content of the seaweed after drying and develop a hybrid model to reduce the outliers. The data were collected with sensors from the v-Groove Hybrid Solar Drier (v-GHSD) at Semporna, South-Eastern Coast of Sabah, Malaysia. After the second order interaction, we have 435 drying parameters, each parameter has 1914 observations. First, we used four machine learning algorithms, such as random forest, support vector machine, bagging and boosting to determine the significant parameters by selecting 15, 25, 35 and 45 parameters. Second, we developed the hybrid model using robust methods such as M. Bi-Square, M. Hampel and M. Huber. The results show that there is a significant improvement in the reduction of the number of outliers and better prediction using hybrid model for the contaminated seaweed big data. For the highest variable importance of 45 significant drying parameters of seaweed, the hybrid model bagging M Bi-square performs better because it has the lowest percentage of outliers of 4.08 %.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122688191","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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