Pub Date : 2023-09-01DOI: 10.46481/jnsps.2023.1402
Elsayed Elshoubary
This study examines a system that consists of three subsystems 1, 2 and 3. These three subsystems are each linked together in series. Subsystem 1’s three units are wired in series, subsystem 2’s three units are wired in parallel and operating under the 2-out-of-3: G; policy, and subsystem 3’s three units are wired in parallel and operating under the 1-out-of-3: G; policy. Units and subsystems failure rates are constant and follow an exponential distribution. The repair rate follow two types of distributions, namely general and Gumbel Hougaard family copula distribution. The system was studied using Laplace transforms and supplementary variable methods. For specific values of the failure and repair rates, availability, reliability, mean time to failure (MTTF), and cost analysis have been assessed. As a means to improve the system’s overall effectiveness and availability, a reduction strategy is utilized. Tables and graphs are used to display computed results.
{"title":"Effect of reduction method on the performance a software defined network system using Gumbel Hougaard family copula distribution","authors":"Elsayed Elshoubary","doi":"10.46481/jnsps.2023.1402","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1402","url":null,"abstract":"This study examines a system that consists of three subsystems 1, 2 and 3. These three subsystems are each linked together in series. Subsystem 1’s three units are wired in series, subsystem 2’s three units are wired in parallel and operating under the 2-out-of-3: G; policy, and subsystem 3’s three units are wired in parallel and operating under the 1-out-of-3: G; policy. Units and subsystems failure rates are constant and follow an exponential distribution. The repair rate follow two types of distributions, namely general and Gumbel Hougaard family copula distribution. The system was studied using Laplace transforms and supplementary variable methods. For specific values of the failure and repair rates, availability, reliability, mean time to failure (MTTF), and cost analysis have been assessed. As a means to improve the system’s overall effectiveness and availability, a reduction strategy is utilized. Tables and graphs are used to display computed results.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129518917","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 : 2023-08-01DOI: 10.46481/jnsps.2023.1576
M. Khan, Chijioke Ezekiel Elum, A. O. Ijeomah, Hilip John Ameji, I. G. Osigbemhe, Emmanuel Etim (PhD), John Veshima Anyam, Alexander S. P. Abel, CyprianTernenge Agber
This study characterizes the bioactive molecules from the bulb of Calotropisprocera and investigates the antimicrobial activities of the crude extracts. Theoretical studies on the two isolated compounds in the crude extract were also accomplished.The bulbs were air dried, pulverized, and subjected to extraction procedures by maceration using 500 mL each of normal-hexane, ethyl acetate and methanol. The crude extracts were further tested onmicroorganisms and phytochemical screening using standard procedures. In addition, the bioactive compounds in the extract were screened against DNA gyrase of two Gram negative bacterial species; Escherichia coli and Salmonella typhiusing Molecular Docking simulation techniques and further subjected to ADMET profiling,using the Swiss ADME online server. The Crude ethyl acetate extract has the highest effective activity against Escherichia coli (MIC 2.5mg / mL and MBC/MFC 5mg / mL), Staphylococcus aureus (MIC 2.5mg/mL), Candida albicans, Salmonella typhiand Candida stellafoidea (MIC 5mg/mL). beta-Amyrin acetate and Taraxasterol are the two phytochemicals in the purified white crystalline fractions and were found to fasten to the active sites of DNA gyrase of the Gram negative bacterial species via hydrophobic and hydrogen bond interactions, with binding activity value of -9.6 kcal/mol and -9.5 kcal/mol, respectively. Also, ADMET investigations of the compounds revealed their sound oral bioavailability and excellent pharmacokinetic and toxicity profiles. The findings of this study could provide a platform for discovering safe and potent antibiotics against pathogenic microbes ravaging our society.
{"title":"Isolation, Characterization, Antimicrobial and Theoretical Investigation of Some Bioactive Compounds Obtained from the Bulbs of Calotropisprocera","authors":"M. Khan, Chijioke Ezekiel Elum, A. O. Ijeomah, Hilip John Ameji, I. G. Osigbemhe, Emmanuel Etim (PhD), John Veshima Anyam, Alexander S. P. Abel, CyprianTernenge Agber","doi":"10.46481/jnsps.2023.1576","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1576","url":null,"abstract":"This study characterizes the bioactive molecules from the bulb of Calotropisprocera and investigates the antimicrobial activities of the crude extracts. Theoretical studies on the two isolated compounds in the crude extract were also accomplished.The bulbs were air dried, pulverized, and subjected to extraction procedures by maceration using 500 mL each of normal-hexane, ethyl acetate and methanol. The crude extracts were further tested onmicroorganisms and phytochemical screening using standard procedures. In addition, the bioactive compounds in the extract were screened against DNA gyrase of two Gram negative bacterial species; Escherichia coli and Salmonella typhiusing Molecular Docking simulation techniques and further subjected to ADMET profiling,using the Swiss ADME online server. The Crude ethyl acetate extract has the highest effective activity against Escherichia coli (MIC 2.5mg / mL and MBC/MFC 5mg / mL), Staphylococcus aureus (MIC 2.5mg/mL), Candida albicans, Salmonella typhiand Candida stellafoidea (MIC 5mg/mL). beta-Amyrin acetate and Taraxasterol are the two phytochemicals in the purified white crystalline fractions and were found to fasten to the active sites of DNA gyrase of the Gram negative bacterial species via hydrophobic and hydrogen bond interactions, with binding activity value of -9.6 kcal/mol and -9.5 kcal/mol, respectively. Also, ADMET investigations of the compounds revealed their sound oral bioavailability and excellent pharmacokinetic and toxicity profiles. The findings of this study could provide a platform for discovering safe and potent antibiotics against pathogenic microbes ravaging our society.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"336 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116126501","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 : 2023-07-26DOI: 10.46481/jnsps.2023.1453
D. Almutairi, Mohamed A.Abdoon, salihah yousuf, Mohamed Salih, Shahinaz A.Elsamani, Fathelrhman EL Guma, Mohammed Berir
Visceral leishmaniosis is one recent example of a global illness that demands our best efforts at understanding. Thus, mathematical modeling may be utilized to learn more about and make better epidemic forecasts. By taking into account the Caputo and Caputo-Fabrizio derivatives, a frictional model of visceral leishmaniosis was mathematically examined based on real data from Gedaref State, Sudan. The stability analysis for Caputo and Caputo-Fabrizio derivatives is analyzed. The suggested ordinary and fractional differential mathematical models are then simulated numerically. Using the Adams-Bashforth method, numerical simulations are conducted. The results demonstrate that the Caputo-Fabrizio derivative yields more precise solutions for fractional differential equations.
{"title":"Modeling and Analysis of a Fractional Visceral Leishmaniosis with Caputo and Caputo–Fabrizio derivatives","authors":"D. Almutairi, Mohamed A.Abdoon, salihah yousuf, Mohamed Salih, Shahinaz A.Elsamani, Fathelrhman EL Guma, Mohammed Berir","doi":"10.46481/jnsps.2023.1453","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1453","url":null,"abstract":"Visceral leishmaniosis is one recent example of a global illness that demands our best efforts at understanding. Thus, mathematical modeling may be utilized to learn more about and make better epidemic forecasts. By taking into account the Caputo and Caputo-Fabrizio derivatives, a frictional model of visceral leishmaniosis was mathematically examined based on real data from Gedaref State, Sudan. The stability analysis for Caputo and Caputo-Fabrizio derivatives is analyzed. The suggested ordinary and fractional differential mathematical models are then simulated numerically. Using the Adams-Bashforth method, numerical simulations are conducted. The results demonstrate that the Caputo-Fabrizio derivative yields more precise solutions for fractional differential equations.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128920864","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 : 2023-06-22DOI: 10.46481/jnsps.2023.1512
Suha Ibrahim Salih Al-Ali, Nihad Jalal Kadhem AL-Awsi
This study investigates the impact of extracting fresh water from areas where salt water and fresh water meet in tropical regions. Traditionally, fresh water is expected to be found above salt water in the ocean or underground. To carry out the investigation, Green's Function method is used, and a numerical chart is presented that includes an equation derived from Green's II matching. The study computes the shape of the interface during water withdrawal and flows through the basins and sources of the line. In addition, this study obtains an analytical solution to the linear problem for the non-withdrawal scenario. Finally, the study identifies the maximum rate of water withdrawal before the initial breakthrough of salt water for different density ratios.
{"title":"Simulation of the Movement of Groundwater in an Aquifer","authors":"Suha Ibrahim Salih Al-Ali, Nihad Jalal Kadhem AL-Awsi","doi":"10.46481/jnsps.2023.1512","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1512","url":null,"abstract":"This study investigates the impact of extracting fresh water from areas where salt water and fresh water meet in tropical regions. Traditionally, fresh water is expected to be found above salt water in the ocean or underground. To carry out the investigation, Green's Function method is used, and a numerical chart is presented that includes an equation derived from Green's II matching. The study computes the shape of the interface during water withdrawal and flows through the basins and sources of the line. In addition, this study obtains an analytical solution to the linear problem for the non-withdrawal scenario. Finally, the study identifies the maximum rate of water withdrawal before the initial breakthrough of salt water for different density ratios.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132094181","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 : 2023-06-21DOI: 10.46481/jnsps.2023.1438
A. H. Labulo, Augustine D. Terna, O. Oladayo, H. Brahim, N. Tanko, R. A. Ashonibare, J. D. Opeyemi, Z. Tywabi-Ngeva
This study investigated the photocatalytic and antibacterial activities of plant-mediated silver nanoparticles (AgNPs) from a medicinal plant extract of Khaya senegalensis (K. senegalensis) and oxygen functionalized carbon nanotubes (oCNTs), respectively. The CNTs were functionalized using acid treatment. The green synthesized AgNPs from K. senegalensis (KS-AgNPs) and oCNTs were characterized by UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission emission microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The formation of KS-AgNPs was confirmed by the UV–Vis absorption spectra, which showed an absorption band at 427 nm with a color change from yellow to brown. The morphology of KS-AgNPs was spherical in shape, with an average particle size of 9.30 nm. The FTIR analyses revealed distinctive functional groups, such as, hydroxyl (O-H), amines (N-H), and carbonyl (C-O), which were directly involved in the synthesis and stability of AgNPs. The XRD spectra was distinctive with five intense peaks at 2theta angles of 38.12°, 44.28°, 64.43°, 77.48°, and 81.54o while oCNTs gave intense peaks at 2theta angles of 26.43o, 42.36o, 44.46o, 54.51o, 59.98o, and 77.40o. The photocatalytic property of green synthesized KS-AgNPs was determined to be 40.7 % higher than that of oCNTs when applied for treatment of industrial waste water. The ability of green-mediated KS-AgNPs to inhibit against gram-positive and gram-negative bacteria was observed to be that gram (-) bacteria (E. coli) was more susceptible to KS-AgNPs than the gram (+) bacteria (S. aureus), in which case their susceptibility was least in oCNTs for both bacteria, respectively.
研究了药用植物senegalensis Khaya senegalensis (K. senegalensis)和氧功能化碳纳米管(oCNTs)中植物介导的银纳米颗粒(AgNPs)的光催化和抗菌活性。采用酸处理对碳纳米管进行功能化处理。采用紫外可见光谱、傅里叶变换红外光谱(FTIR)、透射发射显微镜(TEM)、扫描电子显微镜(SEM)和x射线衍射(XRD)对绿色合成的senegalensis AgNPs (KS-AgNPs)和oCNTs进行了表征。紫外-可见吸收光谱证实了KS-AgNPs的形成，在427 nm处有一个由黄色变为棕色的吸收带。KS-AgNPs的形貌为球形，平均粒径为9.30 nm。FTIR分析揭示了不同的官能团，如羟基(O-H)，胺(N-H)和羰基(C-O)，它们直接参与AgNPs的合成和稳定性。XRD光谱特征明显，在2角为38.12°、44.28°、64.43°、77.48°和81.54°处有5个强峰，而ocnt在2角为26.43°、42.36°、44.46°、54.51°、59.98°和77.40°处有5个强峰。绿色合成的KS-AgNPs在处理工业废水时的光催化性能比ocnt高40.7%。绿色介导的KS-AgNPs对革兰氏阳性菌和革兰氏阴性菌的抑制能力观察到，革兰氏(-)菌(大肠杆菌)比革兰氏(+)菌(金黄色葡萄球菌)对KS-AgNPs更敏感，在这种情况下，它们对两种细菌的ocnt的敏感性分别最低。
{"title":"Photocatalytic and antibacterial activities of green-mediated Khaya senegalensis-silver nanoparticles and oxidized carbon nanotubes","authors":"A. H. Labulo, Augustine D. Terna, O. Oladayo, H. Brahim, N. Tanko, R. A. Ashonibare, J. D. Opeyemi, Z. Tywabi-Ngeva","doi":"10.46481/jnsps.2023.1438","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1438","url":null,"abstract":"This study investigated the photocatalytic and antibacterial activities of plant-mediated silver nanoparticles (AgNPs) from a medicinal plant extract of Khaya senegalensis (K. senegalensis) and oxygen functionalized carbon nanotubes (oCNTs), respectively. The CNTs were functionalized using acid treatment. The green synthesized AgNPs from K. senegalensis (KS-AgNPs) and oCNTs were characterized by UV–Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission emission microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The formation of KS-AgNPs was confirmed by the UV–Vis absorption spectra, which showed an absorption band at 427 nm with a color change from yellow to brown. The morphology of KS-AgNPs was spherical in shape, with an average particle size of 9.30 nm. The FTIR analyses revealed distinctive functional groups, such as, hydroxyl (O-H), amines (N-H), and carbonyl (C-O), which were directly involved in the synthesis and stability of AgNPs. The XRD spectra was distinctive with five intense peaks at 2theta angles of 38.12°, 44.28°, 64.43°, 77.48°, and 81.54o while oCNTs gave intense peaks at 2theta angles of 26.43o, 42.36o, 44.46o, 54.51o, 59.98o, and 77.40o. The photocatalytic property of green synthesized KS-AgNPs was determined to be 40.7 % higher than that of oCNTs when applied for treatment of industrial waste water. The ability of green-mediated KS-AgNPs to inhibit against gram-positive and gram-negative bacteria was observed to be that gram (-) bacteria (E. coli) was more susceptible to KS-AgNPs than the gram (+) bacteria (S. aureus), in which case their susceptibility was least in oCNTs for both bacteria, respectively.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127808833","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 : 2023-06-14DOI: 10.46481/jnsps.2023.1180
A. Fasasi, E. Ajenifuja, E. Osagie, L. Animashaun, Abiodun Eyitayo Adeoye, E. Obiajunwa
Copper-doped hematite thin films were prepared by spray pyrolysis technique using a mixture of ethanol and distilled water precursors. Visual observations showed that aqua precursor produced films of less integrity compared with ethanol that produced thin, uniform and transparent yellowish-brown films that adhered well to the substrate. Composition and thickness measurements determined by RBS revealed that ethanol precursor produced thinner films of 94.45 and 51.77 nm while aqua precursor produced films of 1,370 and 1,120 nm for undoped and Cu-doped Fe2O3 respectively. This is an indication that ethanol solutions produced nano-thick films of high integrity. The composition revealed that only the Cu-doped Fe2O3 deposited by ethanol solution gave composition close to stoichiometric Fe2O3 while the others gave non-stoichiometric Fe(OH)3 . Optical characterization carried out using UV-visible spectrophotometer in transmittance mode indicated that the film thickness was directly proportional to the number of passes which is inversely proportional to the transmittance. Three bandgap determination methods namely; Tauc, Absorption Fitting Spectrum (AFS) and Davis-Mott were employed with the result that Tauc and AFS gave close direct and indirect bandgap energies (Eg) of 3.44 and 1.98 for AFS and 3.43 and 2.32 eV for Tauc respectively. The Urbach tail energy determined was 1,100 meV which is an indication of a broad onset of absorption. The steepness parameter (?) was found to be 7.83 while the electron-phonon (Eph ) coupling energy was found to be 0.85 eV. It was also observed that the refractive index (n) was about 15 times greater than the extinction coefficient (k). In the study of the dispersion parameters using single oscillator and Sellmier models, the values of the single oscillator energy (Eosc ), dispersion energy (Ed), zero frequency dielectric constant, zero frequency refractive index, the average oscillator strength (So), the average oscillator parameter and the dispersion parameters were determined. All the values of the parameters estimated are of the same order of magnitude with other semiconducting materials. The study showed that Cu-doped Fe2O3 could be employed as dielectric material as well as in optoelectronic devices.
{"title":"Optical, Dielectric and Optoelectronic Properties of Spray Deposited Cu-doped Fe2O3 Thin Films","authors":"A. Fasasi, E. Ajenifuja, E. Osagie, L. Animashaun, Abiodun Eyitayo Adeoye, E. Obiajunwa","doi":"10.46481/jnsps.2023.1180","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1180","url":null,"abstract":"Copper-doped hematite thin films were prepared by spray pyrolysis technique using a mixture of ethanol and distilled water precursors. Visual observations showed that aqua precursor produced films of less integrity compared with ethanol that produced thin, uniform and transparent yellowish-brown films that adhered well to the substrate. Composition and thickness measurements determined by RBS revealed that ethanol precursor produced thinner films of 94.45 and 51.77 nm while aqua precursor produced films of 1,370 and 1,120 nm for undoped and Cu-doped Fe2O3 respectively. This is an indication that ethanol solutions produced nano-thick films of high integrity. The composition revealed that only the Cu-doped Fe2O3 deposited by ethanol solution gave composition close to stoichiometric Fe2O3 while the others gave non-stoichiometric Fe(OH)3 . Optical characterization carried out using UV-visible spectrophotometer in transmittance mode indicated that the film thickness was directly proportional to the number of passes which is inversely proportional to the transmittance. Three bandgap determination methods namely; Tauc, Absorption Fitting Spectrum (AFS) and Davis-Mott were employed with the result that Tauc and AFS gave close direct and indirect bandgap energies (Eg) of 3.44 and 1.98 for AFS and 3.43 and 2.32 eV for Tauc respectively. The Urbach tail energy determined was 1,100 meV which is an indication of a broad onset of absorption. The steepness parameter (?) was found to be 7.83 while the electron-phonon (Eph ) coupling energy was found to be 0.85 eV. It was also observed that the refractive index (n) was about 15 times greater than the extinction coefficient (k). In the study of the dispersion parameters using single oscillator and Sellmier models, the values of the single oscillator energy (Eosc ), dispersion energy (Ed), zero frequency dielectric constant, zero frequency refractive index, the average oscillator strength (So), the average oscillator parameter and the dispersion parameters were determined. All the values of the parameters estimated are of the same order of magnitude with other semiconducting materials. The study showed that Cu-doped Fe2O3 could be employed as dielectric material as well as in optoelectronic devices.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127954211","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 : 2023-06-14DOI: 10.46481/jnsps.2023.1514
Oluwayemisi O Alaba, B. G. Kibria
This paper considers the Ridge Feasible Generalized Least Squares Estimator (RFGLSE), Ridge Seemingly Unrelated Regression RSUR and proposes the Kibria-Lukman KLSUR estimator for the parameters of the Seemingly Unrelated Regression (SUR) model when the regressors of the models are collinear. A simulation study was conducted to compare the performance of the three different types of estimators for the SUR model. Different correlation levels (0.0, 0.1, 0.2, ..., 0.9) among the independent variables, sample sizes replicated 10000 times and contemporaneous error correlation (0.0, 0.1, 0.2, ..., 0.9) among the equations were assumed for the simulation study. The efficiency of the three (RFGLSE, RSUR, and KLSUR estimators for SUR, when the predictors are correlated, was investigated using the Trace Mean Square Error (TMSE). The results showed that the KLSUR estimator outperformed the other estimators except for a few cases when the sample size is small.
{"title":"The Efficiency of the K-L Estimator for the Seemingly Unrelated Regression Model: Simulation and Application","authors":"Oluwayemisi O Alaba, B. G. Kibria","doi":"10.46481/jnsps.2023.1514","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1514","url":null,"abstract":"This paper considers the Ridge Feasible Generalized Least Squares Estimator (RFGLSE), Ridge Seemingly Unrelated Regression RSUR and proposes the Kibria-Lukman KLSUR estimator for the parameters of the Seemingly Unrelated Regression (SUR) model when the regressors of the models are collinear. A simulation study was conducted to compare the performance of the three different types of estimators for the SUR model. Different correlation levels (0.0, 0.1, 0.2, ..., 0.9) among the independent variables, sample sizes replicated 10000 times and contemporaneous error correlation (0.0, 0.1, 0.2, ..., 0.9) among the equations were assumed for the simulation study. The efficiency of the three (RFGLSE, RSUR, and KLSUR estimators for SUR, when the predictors are correlated, was investigated using the Trace Mean Square Error (TMSE). The results showed that the KLSUR estimator outperformed the other estimators except for a few cases when the sample size is small.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129839584","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 : 2023-06-14DOI: 10.46481/jnsps.2023.1371
S. Hadisaputra, L. R. Savalas
Theoretical studies have been carried out using DFT, ab initio MP2 and Monte Carlo (MC) simulations of corrosion inhibitors from lawsone derivatives against carbon steel. The research focuses on studying the effect of substituent groups in the lawsone structure on the efficiency of corrosion inhibition in mild steel. Quantum chemical parameters of lawstone inhibitors in neutral and protonated conditions have been calculated. Fukui’s function analysis predicts that the active side of the inhibitor will be adsorbed on the mild steel surface. MC simulation is used to understand the adsorption patterns of lawsone compounds on metal surfaces. The organic inhibitor L-NH2 has better performance as a corrosion inhibitor for mild steel in neutral or protonated conditions.
{"title":"Corrosion Inhibition Properties of Lawsone Derivatives againts Mild Steel: A Theoretical Study","authors":"S. Hadisaputra, L. R. Savalas","doi":"10.46481/jnsps.2023.1371","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1371","url":null,"abstract":"Theoretical studies have been carried out using DFT, ab initio MP2 and Monte Carlo (MC) simulations of corrosion inhibitors from lawsone derivatives against carbon steel. The research focuses on studying the effect of substituent groups in the lawsone structure on the efficiency of corrosion inhibition in mild steel. Quantum chemical parameters of lawstone inhibitors in neutral and protonated conditions have been calculated. Fukui’s function analysis predicts that the active side of the inhibitor will be adsorbed on the mild steel surface. MC simulation is used to understand the adsorption patterns of lawsone compounds on metal surfaces. The organic inhibitor L-NH2 has better performance as a corrosion inhibitor for mild steel in neutral or protonated conditions.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132807005","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 : 2023-06-11DOI: 10.46481/jnsps.2023.1435
K. Sanni, Adeshola Adediran, Aliu Tajudeen
This paper discusses two-dimensional heat flow of an incompressible non-Newtonian hydromagnetic fluid over a power-law stretching curved sheet. The energy equation of the flow problem considers a radiative flux influenced by viscous dissipation and surface frictional heating. Lorentz force and Joule heating are taken in the consequence of applied variable magnetic field satisfying solenoidal nature of magnetism. The governing equations are reduced to boundary-layer regime using dimensionless quantities and the resulting PDEs are converted into ODEs by suitable similarity variables. The flow fields; velocity and temperature are computed numerically by implementing Keller-Box shooting method with Jacobi iterative technique. Error analysis is calculated to ensure solutions' convergence. Interesting flow parameters are examined and plotted graphically. Results show that velocity is increased for large number of fluid rheology and opposite effects are recorded for increasing curvature, Lorentz force, and stretching power. Flow past a flat and curved surfaces are substantial in validation of this present work.
{"title":"Numerical investigation of nonlinear radiative flux of non-Newtonian MHD fluid induced by nonlinear driven multi-physical curved mechanism with variable magnetic field","authors":"K. Sanni, Adeshola Adediran, Aliu Tajudeen","doi":"10.46481/jnsps.2023.1435","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1435","url":null,"abstract":"This paper discusses two-dimensional heat flow of an incompressible non-Newtonian hydromagnetic fluid over a power-law stretching curved sheet. The energy equation of the flow problem considers a radiative flux influenced by viscous dissipation and surface frictional heating. Lorentz force and Joule heating are taken in the consequence of applied variable magnetic field satisfying solenoidal nature of magnetism. The governing equations are reduced to boundary-layer regime using dimensionless quantities and the resulting PDEs are converted into ODEs by suitable similarity variables. The flow fields; velocity and temperature are computed numerically by implementing Keller-Box shooting method with Jacobi iterative technique. Error analysis is calculated to ensure solutions' convergence. Interesting flow parameters are examined and plotted graphically. Results show that velocity is increased for large number of fluid rheology and opposite effects are recorded for increasing curvature, Lorentz force, and stretching power. Flow past a flat and curved surfaces are substantial in validation of this present work.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114554520","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 : 2023-06-11DOI: 10.46481/jnsps.2023.1437
Y. Bello, W. B. Yahya, A. Abdulraheem
In clustered data, observations within a cluster show similarity between themselves because they share common features different from observations in the other clusters. In a given population, different clustering may surface because correlation may occur across more than one dimension. The existing multilevel analysis techniques of the primal linear mixed-effect models are limited to natural clusters which are often not realistic to capture in real-life situations. Therefore, this paper proposes dual linear mixed models (DLMMs) for modeling unobserved latent clusters when such are present in data sets to yield appreciable gains in model fitness and predictive accuracy. The methodology explored the development and analysis of the dual linear mixed models (DLMMs) based on the derived latent clusters from the natural clusters using multivariate cluster analysis. A published data set on political analysis was used to demonstrate the efficiency of the proposed models. The proposed DLMMs have yielded minimum values of the models' assessment criteria (Akaike information criterion, Bayesian information criterion, and root mean squared error), and hence, outperformed the classical PLMMs in terms of model fitness and predictive accuracy.
{"title":"Model Fitness and Predictive Accuracy in Linear Mixed-Effects Models with Latent Clusters","authors":"Y. Bello, W. B. Yahya, A. Abdulraheem","doi":"10.46481/jnsps.2023.1437","DOIUrl":"https://doi.org/10.46481/jnsps.2023.1437","url":null,"abstract":"In clustered data, observations within a cluster show similarity between themselves because they share common features different from observations in the other clusters. In a given population, different clustering may surface because correlation may occur across more than one dimension. The existing multilevel analysis techniques of the primal linear mixed-effect models are limited to natural clusters which are often not realistic to capture in real-life situations. Therefore, this paper proposes dual linear mixed models (DLMMs) for modeling unobserved latent clusters when such are present in data sets to yield appreciable gains in model fitness and predictive accuracy. The methodology explored the development and analysis of the dual linear mixed models (DLMMs) based on the derived latent clusters from the natural clusters using multivariate cluster analysis. A published data set on political analysis was used to demonstrate the efficiency of the proposed models. The proposed DLMMs have yielded minimum values of the models' assessment criteria (Akaike information criterion, Bayesian information criterion, and root mean squared error), and hence, outperformed the classical PLMMs in terms of model fitness and predictive accuracy.","PeriodicalId":342917,"journal":{"name":"Journal of the Nigerian Society of Physical Sciences","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132138166","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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