I. A. Mohammed, S. I. Mustapha, F. Aderibigbe, H. U. Hambali, A. M. Afolabi, K. B. Muritala, U. M. Aliyu
As an alternative to the physical storage of hydrogen as compressed gas or liquid hydrogen requiring high-pressure tanks and cryogenic temperatures, the material-based storage of hydrogen in solids involves hydrogen uptake and release from the surface of adsorbents or within interstitials of hydrides. We report a hydrothermic reduction of rutile-ilmenite mineral into hydrogen-rich fibrous products, η-Ti2FeO0.2H2.8, in an ethanol-water system at 120°C for 4 hrs. As part of a project to generate hydrogen from water-ethanol system using advanced catalysts containing graphene oxide (GO) as carbon source, a system of 62.5 μg graphene oxide per g of rutile-ilmenite mineral was employed in a concentration of 50 mg/mL of ethanol-water solution. As well as in the original mineral, XRD of thermal annealed mineral between 500 and 800°C showed no hydride or phase change in rutile-ilmenite. With hydrothermal treatment of GO/rutile-ilmenite (50 mg/mL) in ethanol-water (1:1 v/v) at 120°C, a hydrogen-rich ferrotitanium hydride phase was formed, and there was a change in morphology from plate-like and granular particles into fibrous structures. Like the release of hydrogen by its ‘carriers’ (e.g., CaH2, NH4BH4, NaBH4, NH3, formic acid), it is anticipated that hydrogen was generated from the ethanol-water system in-situ, which reduced the rutile-ilmenite mineral into a hydride. EDX results showed that the reduction affected specifically the oxides of Fe and aluminosilicates in the mineral. The study demonstrated a possibility of in-situ hydrogen generation and storage via low-temperature graphene oxide hydrothermic reduction of rutile-ilmenite mineral in an ethanol-water system.
{"title":"Hydrothermic reduction of rutile-ilmenite mineral producing an oxyhydride η-Ti2FeO0.2H2.8: Towards in-situ hydrogen production and storage","authors":"I. A. Mohammed, S. I. Mustapha, F. Aderibigbe, H. U. Hambali, A. M. Afolabi, K. B. Muritala, U. M. Aliyu","doi":"10.4314/njtd.v21i1.2133","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.2133","url":null,"abstract":"As an alternative to the physical storage of hydrogen as compressed gas or liquid hydrogen requiring high-pressure tanks and cryogenic temperatures, the material-based storage of hydrogen in solids involves hydrogen uptake and release from the surface of adsorbents or within interstitials of hydrides. We report a hydrothermic reduction of rutile-ilmenite mineral into hydrogen-rich fibrous products, η-Ti2FeO0.2H2.8, in an ethanol-water system at 120°C for 4 hrs. As part of a project to generate hydrogen from water-ethanol system using advanced catalysts containing graphene oxide (GO) as carbon source, a system of 62.5 μg graphene oxide per g of rutile-ilmenite mineral was employed in a concentration of 50 mg/mL of ethanol-water solution. As well as in the original mineral, XRD of thermal annealed mineral between 500 and 800°C showed no hydride or phase change in rutile-ilmenite. With hydrothermal treatment of GO/rutile-ilmenite (50 mg/mL) in ethanol-water (1:1 v/v) at 120°C, a hydrogen-rich ferrotitanium hydride phase was formed, and there was a change in morphology from plate-like and granular particles into fibrous structures. Like the release of hydrogen by its ‘carriers’ (e.g., CaH2, NH4BH4, NaBH4, NH3, formic acid), it is anticipated that hydrogen was generated from the ethanol-water system in-situ, which reduced the rutile-ilmenite mineral into a hydride. EDX results showed that the reduction affected specifically the oxides of Fe and aluminosilicates in the mineral. The study demonstrated a possibility of in-situ hydrogen generation and storage via low-temperature graphene oxide hydrothermic reduction of rutile-ilmenite mineral in an ethanol-water system.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"65 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140252167","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}
H. U. Hambali, T. Jimoh, T. L. Peng, A. A. Umar, B. T. Mutiullah, J. A. Okolie
Indubitably, the combustion of fossils fuels has really hampered the preservation of the environment as it raises the content of CO2 in the atmosphere which consequentially results in global warming. Adsorption process remains the popular technique owing to its cost-effectiveness, faster reaction rates and flexible design. This review detailed the research progress in preparation of modified zeolite-based and novel adsorbents towards enhanced CO2 capture. In addition, the review presents an overview on available techniques of capturing CO2 and mechanism of reaction. Large surface area, distinctive mechanical characteristics and uniform dispersion of the exchangeable cations in the porous framework is prerequisite for high adsorption capacity and stability over zeolite materials. Novel nanostructured and polymeric zeolite composite materials seem promising because they offer solutions to energy-related problems while also contributing to environmental preservation. It is anticipated that this review could offer a conclusive roadmap in the pursuit of a cost-effective, industrially potent adsorbent suited for enhance CO2 capture.
{"title":"A review on CO2 capture over novel adsorbents: Progress in robust zeolite adsorbent development","authors":"H. U. Hambali, T. Jimoh, T. L. Peng, A. A. Umar, B. T. Mutiullah, J. A. Okolie","doi":"10.4314/njtd.v21i1.2235","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.2235","url":null,"abstract":"Indubitably, the combustion of fossils fuels has really hampered the preservation of the environment as it raises the content of CO2 in the atmosphere which consequentially results in global warming. Adsorption process remains the popular technique owing to its cost-effectiveness, faster reaction rates and flexible design. This review detailed the research progress in preparation of modified zeolite-based and novel adsorbents towards enhanced CO2 capture. In addition, the review presents an overview on available techniques of capturing CO2 and mechanism of reaction. Large surface area, distinctive mechanical characteristics and uniform dispersion of the exchangeable cations in the porous framework is prerequisite for high adsorption capacity and stability over zeolite materials. Novel nanostructured and polymeric zeolite composite materials seem promising because they offer solutions to energy-related problems while also contributing to environmental preservation. It is anticipated that this review could offer a conclusive roadmap in the pursuit of a cost-effective, industrially potent adsorbent suited for enhance CO2 capture.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"18 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140254478","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}
K. A. Bello, M. Kanakana-Katumba, R. Maladzhi, C. O. Omoyi, Author Contributions Conceptualization, M. Kanakana-Katumba, K. methodology, M. G. .Bello, R. W. Kanakana-Katumba, Maladzhi C.O, K. Omoyi, Omoyi, .Bello
The digital revolution is the future pathway to experiencing business evolution. It will be difficult for any organization to remain in business without deploying fourth industry revolution (4IR) techniques. This review guides prospective business owners on the need to embrace Smart Manufacturing (SM) timely and appropriate to enhance their business performance indicators. Many manufacturing companies are facing challenges in adopting SM tools in their organization due to a lack of essential resources despite the benefits associated with SM. Therefore, this study systematically reviewed the criteria evaluation techniques in implementing digital factories. This work has analysed small, medium, and micro enterprises (SMME), with the view to enumerate the appropriate criteria to determine the level of digital technology tools adoption framework. It also highlights how to compensate for the inadequate technical and financial resources in SM. The guidelines for SM implementation adoption in SMME is a research gap that was missing in previous studies. SM benefits, challenges, applications, significance, impact, and future perspectives, are discussed. Evaluation Criteria for SM Adoption practices were also expounded. The framework used in this study will help SMME owners to adopt SM.
数字革命是未来企业发展的必经之路。如果不采用第四次工业革命（4IR）技术，任何组织都很难继续经营下去。本综述将指导未来的企业主及时、适当地采用智能制造（SM），以提高其业务绩效指标。尽管智能制造有诸多好处，但由于缺乏必要的资源，许多制造企业在采用智能制造工具方面面临挑战。因此，本研究系统回顾了实施数字化工厂的标准评估技术。这项工作对中小型和微型企业（SMME）进行了分析，目的是列举适当的标准，以确定数字技术工具采用框架的水平。它还强调了如何弥补中小微企业技术和财政资源不足的问题。在中小型企业中采用 SM 实施准则是以往研究中缺少的一个研究空白。报告讨论了 SM 的好处、挑战、应用、意义、影响和未来展望。此外，还阐述了采用 SM 做法的评估标准。本研究采用的框架将有助于中小型企业主采用 SM。
{"title":"Recent advances in smart manufacturing: a case study of small, medium, and micro enterprises (SMME)","authors":"K. A. Bello, M. Kanakana-Katumba, R. Maladzhi, C. O. Omoyi, Author Contributions Conceptualization, M. Kanakana-Katumba, K. methodology, M. G. .Bello, R. W. Kanakana-Katumba, Maladzhi C.O, K. Omoyi, Omoyi, .Bello","doi":"10.4314/njtd.v21i1.1905","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.1905","url":null,"abstract":"The digital revolution is the future pathway to experiencing business evolution. It will be difficult for any organization to remain in business without deploying fourth industry revolution (4IR) techniques. This review guides prospective business owners on the need to embrace Smart Manufacturing (SM) timely and appropriate to enhance their business performance indicators. Many manufacturing companies are facing challenges in adopting SM tools in their organization due to a lack of essential resources despite the benefits associated with SM. Therefore, this study systematically reviewed the criteria evaluation techniques in implementing digital factories. This work has analysed small, medium, and micro enterprises (SMME), with the view to enumerate the appropriate criteria to determine the level of digital technology tools adoption framework. It also highlights how to compensate for the inadequate technical and financial resources in SM. The guidelines for SM implementation adoption in SMME is a research gap that was missing in previous studies. SM benefits, challenges, applications, significance, impact, and future perspectives, are discussed. Evaluation Criteria for SM Adoption practices were also expounded. The framework used in this study will help SMME owners to adopt SM.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"20 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253619","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}
Carbon fiber-reinforced plastic (CFRP) composite materials are challenging to machine due to their anisotropy and heterogeneity. Thus, the experimental study of milling CFRP composite material is very crucial. In the current study, based on Taguchi’s L9 orthogonal array, slot milling experiments were performed on CFRP composite samples to make a decision on a parametric optimization of multiple responses such as material removal rate (MRR), delamination factor (Fd) and surface roughness (Ra) using grey relational-based Taguchi analysis. The selected milling parameters are cutting speed (A), feed (B), and depth of cut (C). Based on Grey Relational Grade (GRG), Analysis of Variance (ANOVA) was used to determine the parameters' significant contributions and the parameters' optimal levels. The results showed, with a 95% confidence level, that all of the chosen cutting parameters have a substantial impact on all of the measured responses. Based on a confirmatory test performed under ideal milling conditions, MRR has been increased with an improvement of 31.25 %, Fd has been decreased with an improvement of 1.66% and Ra has been decreased with an improvement of 28.3%. These improvements in all measured responses are equivalent to an improvement of GRG by 3%.
{"title":"Multi optimization in slot milling of CFRP composites through grey relational- based Taguchi analysis","authors":"A. Bahei El-Deen","doi":"10.4314/njtd.v21i1.1762","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.1762","url":null,"abstract":"Carbon fiber-reinforced plastic (CFRP) composite materials are challenging to machine due to their anisotropy and heterogeneity. Thus, the experimental study of milling CFRP composite material is very crucial. In the current study, based on Taguchi’s L9 orthogonal array, slot milling experiments were performed on CFRP composite samples to make a decision on a parametric optimization of multiple responses such as material removal rate (MRR), delamination factor (Fd) and surface roughness (Ra) using grey relational-based Taguchi analysis. The selected milling parameters are cutting speed (A), feed (B), and depth of cut (C). Based on Grey Relational Grade (GRG), Analysis of Variance (ANOVA) was used to determine the parameters' significant contributions and the parameters' optimal levels. The results showed, with a 95% confidence level, that all of the chosen cutting parameters have a substantial impact on all of the measured responses. Based on a confirmatory test performed under ideal milling conditions, MRR has been increased with an improvement of 31.25 %, Fd has been decreased with an improvement of 1.66% and Ra has been decreased with an improvement of 28.3%. These improvements in all measured responses are equivalent to an improvement of GRG by 3%.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"32 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140254000","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}
Electromagnetic performance of three different types of double stator permanent magnet machine is analyzed and compared in this study. The analyzed machines in this study are Machine 1, Machine 2 and Machine 3. These machines are designated as: M 1, M 2 and M 3, respectively. The studies are implemented using two-dimensional and three-dimensional finite element analysis (2D-FEA and 3D-FEA) methods. The predicted performance indices are: total harmonic distortion of the voltage, torque ripple, cogging torque, winding inductances, output torque and unbalanced magnetic force (UMF). The studies show that the investigated machine types have negligible reluctance torque and thus, similar axes inductance values. Therefore, the machines’ bulk torque components are contributed mainly by the magnets while the armature excitation sources yield lesser torque components. Amongst the compared machines, M 3 type has an outstanding performance in almost all the performance metrics, compared to M 2 and M 1 types. Nevertheless, M 1 machine type has some good attributes, particularly, with respect to its high output torque per applied magnet volume, in addition to its widest operating speed range ability. Low-speed high-torque applications are most suitable for the investigated machines in practice.
本研究对三种不同类型的双定子永磁电机的电磁性能进行了分析和比较。本研究分析的机器分别为机器 1、机器 2 和机器 3。这些机器被命名为M 1、M 2 和 M 3。研究采用二维和三维有限元分析（2D-FEA 和 3D-FEA ）方法进行。预测的性能指标包括：电压总谐波失真、转矩纹波、齿槽转矩、绕组电感、输出转矩和不平衡磁力（UMF）。研究表明，所研究的机器类型的磁阻转矩可以忽略不计，因此轴电感值也相似。因此，机器的大部分转矩成分主要来自磁体，而电枢励磁源产生的转矩成分较少。与 M 2 和 M 1 机型相比，M 3 机型在几乎所有性能指标上都表现出色。不过，M 1 型机器也有一些优点，尤其是单位应用磁体体积输出扭矩大，而且工作速度范围最广。在实际应用中，低速高扭矩应用最适合所研究的机器。
{"title":"Comparative analysis of dual stator machines","authors":"C. Awah","doi":"10.4314/njtd.v21i1.1872","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.1872","url":null,"abstract":"Electromagnetic performance of three different types of double stator permanent magnet machine is analyzed and compared in this study. The analyzed machines in this study are Machine 1, Machine 2 and Machine 3. These machines are designated as: M 1, M 2 and M 3, respectively. The studies are implemented using two-dimensional and three-dimensional finite element analysis (2D-FEA and 3D-FEA) methods. The predicted performance indices are: total harmonic distortion of the voltage, torque ripple, cogging torque, winding inductances, output torque and unbalanced magnetic force (UMF). The studies show that the investigated machine types have negligible reluctance torque and thus, similar axes inductance values. Therefore, the machines’ bulk torque components are contributed mainly by the magnets while the armature excitation sources yield lesser torque components. Amongst the compared machines, M 3 type has an outstanding performance in almost all the performance metrics, compared to M 2 and M 1 types. Nevertheless, M 1 machine type has some good attributes, particularly, with respect to its high output torque per applied magnet volume, in addition to its widest operating speed range ability. Low-speed high-torque applications are most suitable for the investigated machines in practice.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"82 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140254614","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}
Research has been conducted to analyze and characterize ten 3D printing materials as potential Radiological Phantoms of Lung Organs. Eight filaments of PLA, ABS, HIPS, Carbon, Nylon, TPU, PETG, and Wood were printed using an FDM type 3D printer, and two resins, PLA resin and Water washable resin, were printed using an SLA type 3D printer. The phantoms were printed with thickness variations of 3 mm, 6 mm, and 9 mm. 8 parameters were used to obtain the best material, namely material density, CT number, electron density (Ne), effective electron density (EDG), electron density per volume (EDV), effective atomic number (Zeff), material constituent elements, and elastic Modulus. Based on comparing the values of 8 parameters, the most potential to be used as phantom material for lung organs is PLA.
{"title":"Analysis of 3D printing materials as potential Radiological Phantoms of Lung Organs for medical imaging purposes","authors":"M. Yunianto, F. Anwar, T. Ardyanto","doi":"10.4314/njtd.v21i1.2148","DOIUrl":"https://doi.org/10.4314/njtd.v21i1.2148","url":null,"abstract":"Research has been conducted to analyze and characterize ten 3D printing materials as potential Radiological Phantoms of Lung Organs. Eight filaments of PLA, ABS, HIPS, Carbon, Nylon, TPU, PETG, and Wood were printed using an FDM type 3D printer, and two resins, PLA resin and Water washable resin, were printed using an SLA type 3D printer. The phantoms were printed with thickness variations of 3 mm, 6 mm, and 9 mm. 8 parameters were used to obtain the best material, namely material density, CT number, electron density (Ne), effective electron density (EDG), electron density per volume (EDV), effective atomic number (Zeff), material constituent elements, and elastic Modulus. Based on comparing the values of 8 parameters, the most potential to be used as phantom material for lung organs is PLA.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"68 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140251961","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}
The stability and durability of concrete materials are essential factors in the construction industry. Environmental conditions, such as temperature affect the tensile strength and durability of concrete structures. This work investigates the thermodynamic behaviour of hollow cylindrical concrete using the finite element method (FEM). By deploying ANSYS®, the element mesh was created, and the temperature distribution inside the hollow cylinder was calculated. The effect of the hollowness of the concrete on its heat absorption is determined. The findings demonstrate that the temperature profiles changed radially throughout the concrete thickness. Moreover, it was discovered that the temperature distribution was impacted by the airflow into the cylinder. The numerical experiment in this study was essential in providing a comprehensive understanding of the behaviour of the concrete, particularly when exposed to higher heating rates. This study contributes to the knowledge of the performance and stability of concrete materials. It also demonstrates that the hollowness of the concrete enhances its heat-shielding performance. Furthermore, the inflow of air into the cylinder affects the temperature distribution, with a higher influx of air resulting in lower temperatures. These findings can be utilised to develop appropriate measures to enhance the performance and durability of concrete structures.
{"title":"Numerical Analysis of the Thermodynamic Response of a Hollow Concrete Cylinder","authors":"T.T. Akano, H.O. Onovo, O. S. Osasuyi, S.A. Alabi","doi":"10.4314/njtd.v20i4.2076","DOIUrl":"https://doi.org/10.4314/njtd.v20i4.2076","url":null,"abstract":"The stability and durability of concrete materials are essential factors in the construction industry. Environmental conditions, such as temperature affect the tensile strength and durability of concrete structures. This work investigates the thermodynamic behaviour of hollow cylindrical concrete using the finite element method (FEM). By deploying ANSYS®, the element mesh was created, and the temperature distribution inside the hollow cylinder was calculated. The effect of the hollowness of the concrete on its heat absorption is determined. The findings demonstrate that the temperature profiles changed radially throughout the concrete thickness. Moreover, it was discovered that the temperature distribution was impacted by the airflow into the cylinder. The numerical experiment in this study was essential in providing a comprehensive understanding of the behaviour of the concrete, particularly when exposed to higher heating rates. This study contributes to the knowledge of the performance and stability of concrete materials. It also demonstrates that the hollowness of the concrete enhances its heat-shielding performance. Furthermore, the inflow of air into the cylinder affects the temperature distribution, with a higher influx of air resulting in lower temperatures. These findings can be utilised to develop appropriate measures to enhance the performance and durability of concrete structures. ","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"49 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140429365","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}
S. O. Samuel, C. K. Ojoba, E. P. Ogherohwo, I. Ikhioya
In this study, electrochemical deposition was used to synthesize SrS-doped zirconium materials at a varying voltage of deposition. The XRD result shows that SrS/Zr has a prominent peak intensity corresponding to 2theta values of 26.45o , 33.86o , 38.01o , and 51.49o . The crystal lattice is shown by the prominent peak intensity with higher 2theta degree values; the appearance of an unindexed peak is caused by the substrate utilized for the deposition. SrS surface morphology reveals a Clove-like surface with precipitate visible in the SrS micrograph; the large grain size on the surface of the substrate exhibits photon absorption but lacks any signs of pinholes. At the introduction of zirconium as a dopant to the SrS precursor, there was a drastic change in the precursor which is also noticed on the surface micrograph of the analyzed films. The films show a decrease in thickness from 129.14 to 120.09 nm and an increase in film resistivity from 1.24 x 109 to 1.29 x 109 ohm.m, which further led to a decrease in conductivity from 8.06 x 108 to 7.75 x 108 S/m. The impact of the deposition voltage on the reflectance reveals that lower voltage will stabilize the reflectance of SrS/Zr which will be useful for photovoltaic applications. SrS has an energy bandgap of 1.50 eV while SrS/Zr with bandgap energy of 2.00 – 2.50 eV.
{"title":"Impact of deposition voltage on the physical properties of rare earth element doped strontium sulphide for optoelectronic application","authors":"S. O. Samuel, C. K. Ojoba, E. P. Ogherohwo, I. Ikhioya","doi":"10.4314/njtd.v20i4.1709","DOIUrl":"https://doi.org/10.4314/njtd.v20i4.1709","url":null,"abstract":"In this study, electrochemical deposition was used to synthesize SrS-doped zirconium materials at a varying voltage of deposition. The XRD result shows that SrS/Zr has a prominent peak intensity corresponding to 2theta values of 26.45o , 33.86o , 38.01o , and 51.49o . The crystal lattice is shown by the prominent peak intensity with higher 2theta degree values; the appearance of an unindexed peak is caused by the substrate utilized for the deposition. SrS surface morphology reveals a Clove-like surface with precipitate visible in the SrS micrograph; the large grain size on the surface of the substrate exhibits photon absorption but lacks any signs of pinholes. At the introduction of zirconium as a dopant to the SrS precursor, there was a drastic change in the precursor which is also noticed on the surface micrograph of the analyzed films. The films show a decrease in thickness from 129.14 to 120.09 nm and an increase in film resistivity from 1.24 x 109 to 1.29 x 109 ohm.m, which further led to a decrease in conductivity from 8.06 x 108 to 7.75 x 108 S/m. The impact of the deposition voltage on the reflectance reveals that lower voltage will stabilize the reflectance of SrS/Zr which will be useful for photovoltaic applications. SrS has an energy bandgap of 1.50 eV while SrS/Zr with bandgap energy of 2.00 – 2.50 eV. ","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"42 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140429791","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}
The detection and localization of high impedance faults (HIF) in power systems are challenging due to the low fault current magnitude, which often falls below the detection threshold of conventional devices. HIF events introduce harmonics into the network, posing risks to the safety of connected equipment, including the potential for igniting fire which endangers lives and properties. In this study, Emanuel's HIF model was used to generate HIF signatures resembling real HIF events. Model parameters were adjusted to mimic various contact surface impedances. Two datasets were created: 'no-fault' data, simulating the network without HIF, and 'fault' data, incorporating HIF waveforms by simulating single and multiple lines with the HIF model. The faulted line was divided into five segments along the 33 kV line to capture fault signatures at different locations. The generated data, including current waveforms and magnitudes, were processed and divided into an 80:20 ratio for training, validation, and testing using a deep fully connected Convolutional Neural Network for HIF detection and location. The results showed an impressive accuracy rate of 99.44% and 99.78% for detection and location respectively, representing a significant advancement in HIF detection and location, and offering practical applications for enhancing power line safety.
{"title":"High Impedance Fault Detection and Localization Using Fully-Connected Convolutional Neural Network: A Deep Learning Approach","authors":"I. Abasi-Obot, A.B. Kunya, G. S. Shehu, Y. Jibril","doi":"10.4314/njtd.v20i4.2143","DOIUrl":"https://doi.org/10.4314/njtd.v20i4.2143","url":null,"abstract":"The detection and localization of high impedance faults (HIF) in power systems are challenging due to the low fault current magnitude, which often falls below the detection threshold of conventional devices. HIF events introduce harmonics into the network, posing risks to the safety of connected equipment, including the potential for igniting fire which endangers lives and properties. In this study, Emanuel's HIF model was used to generate HIF signatures resembling real HIF events. Model parameters were adjusted to mimic various contact surface impedances. Two datasets were created: 'no-fault' data, simulating the network without HIF, and 'fault' data, incorporating HIF waveforms by simulating single and multiple lines with the HIF model. The faulted line was divided into five segments along the 33 kV line to capture fault signatures at different locations. The generated data, including current waveforms and magnitudes, were processed and divided into an 80:20 ratio for training, validation, and testing using a deep fully connected Convolutional Neural Network for HIF detection and location. The results showed an impressive accuracy rate of 99.44% and 99.78% for detection and location respectively, representing a significant advancement in HIF detection and location, and offering practical applications for enhancing power line safety. ","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"57 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140431025","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}
I. A. Fetuga, O. Oluwatusin, S. Abolarin, O. O. Olakoyejo, A. O. Adelaja, D.Z. Olaoye, A.S. Adeleke, J. K. Gbegudu, K. S. Aderemi
No Abstract
无摘要
{"title":"Influence of stenosis severity on hemodynamics flow at low Reynolds numbers: A computational fluid dynamic study","authors":"I. A. Fetuga, O. Oluwatusin, S. Abolarin, O. O. Olakoyejo, A. O. Adelaja, D.Z. Olaoye, A.S. Adeleke, J. K. Gbegudu, K. S. Aderemi","doi":"10.4314/njtd.v20i4.1621","DOIUrl":"https://doi.org/10.4314/njtd.v20i4.1621","url":null,"abstract":"No Abstract","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140430001","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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