Pub Date : 2024-09-21DOI: 10.1016/j.rineng.2024.102964
O. Hrechanyі
The problem of forecasting the beginning of the repair effects of equipment under the action of degradation processes was considered. The possibility of using the theory of emissions that form a non-stationary Poisson flow to establish the inspection interval was studied. It was found that when using the theory of emissions while assigning inter-control periods, it is necessary to compare paired correlation coefficients, one of which is r1,δ≫0.9 and tends to unity.
{"title":"Developing an algorithm for planning the periodicity of controls for a random process model","authors":"O. Hrechanyі","doi":"10.1016/j.rineng.2024.102964","DOIUrl":"10.1016/j.rineng.2024.102964","url":null,"abstract":"<div><div>The problem of forecasting the beginning of the repair effects of equipment under the action of degradation processes was considered. The possibility of using the theory of emissions that form a non-stationary Poisson flow to establish the inspection interval was studied. It was found that when using the theory of emissions while assigning inter-control periods, it is necessary to compare paired correlation coefficients, one of which is <em>r</em><sub><em>1,δ</em></sub>≫0.9 and tends to unity.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102964"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012192/pdfft?md5=ae683fc3db98698089e553a35ccb5c5f&pid=1-s2.0-S2590123024012192-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.rineng.2024.102958
Serdar Ekinci , Davut Izci , Ozay Can , Mohit Bajaj , Vojtech Blazek
Maintaining a stable balance between generated power and load demand is a critical challenge in modern power systems, especially with the increasing integration of renewable energy sources like photovoltaic (PV) systems. This study introduces a novel hybrid educational competition optimizer with pattern search (hECO-PS) algorithm to optimally tune a cascaded proportional-derivative with filter and proportional-integral (PDN-PI) controller for load frequency control (LFC) in a two-area power system comprising a PV system and a reheat thermal power system. The proposed hECO-PS algorithm enhances both global exploration and local exploitation capabilities, resulting in superior convergence rates and solution accuracy. The controller's performance was evaluated under various scenarios, including a 10 % step load change and solar radiation variations, demonstrating significant improvements in frequency regulation. The hECO-PS tuned PDN-PI controller achieved a minimum integral of time-weighted absolute error (ITAE) value of 0.4464, outperforming conventional methods like the modified whale optimization algorithm and sea horse algorithm, which yielded ITAE values of 2.6198 and 0.8598, respectively. Furthermore, the proposed controller reduced settling time by up to 46 % and minimized overshoot by up to 40 %. These results confirm the efficacy of the proposed approach in enhancing system stability and reliability under dynamic operating conditions, suggesting it as a promising solution for LFC in modern power systems with high renewable energy penetration.
{"title":"Frequency regulation of PV-reheat thermal power system via a novel hybrid educational competition optimizer with pattern search and cascaded PDN-PI controller","authors":"Serdar Ekinci , Davut Izci , Ozay Can , Mohit Bajaj , Vojtech Blazek","doi":"10.1016/j.rineng.2024.102958","DOIUrl":"10.1016/j.rineng.2024.102958","url":null,"abstract":"<div><div>Maintaining a stable balance between generated power and load demand is a critical challenge in modern power systems, especially with the increasing integration of renewable energy sources like photovoltaic (PV) systems. This study introduces a novel hybrid educational competition optimizer with pattern search (hECO-PS) algorithm to optimally tune a cascaded proportional-derivative with filter and proportional-integral (PDN-PI) controller for load frequency control (LFC) in a two-area power system comprising a PV system and a reheat thermal power system. The proposed hECO-PS algorithm enhances both global exploration and local exploitation capabilities, resulting in superior convergence rates and solution accuracy. The controller's performance was evaluated under various scenarios, including a 10 % step load change and solar radiation variations, demonstrating significant improvements in frequency regulation. The hECO-PS tuned PDN-PI controller achieved a minimum integral of time-weighted absolute error (ITAE) value of 0.4464, outperforming conventional methods like the modified whale optimization algorithm and sea horse algorithm, which yielded ITAE values of 2.6198 and 0.8598, respectively. Furthermore, the proposed controller reduced settling time by up to 46 % and minimized overshoot by up to 40 %. These results confirm the efficacy of the proposed approach in enhancing system stability and reliability under dynamic operating conditions, suggesting it as a promising solution for LFC in modern power systems with high renewable energy penetration.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102958"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012131/pdfft?md5=4ce039ed05622d2462e14647bf0ffe09&pid=1-s2.0-S2590123024012131-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.rineng.2024.102950
Fidelis E. Abeng , Benedict I. Ita , Magdalene E. Ikpi , Vitalis I. Chukwuike , Alexander I. Ikeuba , Moses M. Edim , Maduabuchi A. Chidiebere , Abhinay Thakur , Valentine C. Anadebe
The development of environmentally friendly corrosion inhibitors is becoming more popular since conventional inhibitors are poisonous and non-biodegradable. The anti-corrosive effectiveness of Millettia aboensis leaves extract (MALE) has been assessed in this study using several methods, such as electrochemical measurements, X-ray Photoelectron spectroscopy and scanning electron microscopy on mild steel in acidic solution. Gas chromatography-mass spectrometry (GC-MS) analysis was combined with qualitative and quantitative phytochemical analysis to identify the phytochemicals linked to the activity of the Millettia aboensis extracts and identified key phytoconstituents such as Hexanedioic acid, Phenol derivatives, Octadecanoic acid, and Linolenic acid, which play significant roles in the extract's inhibitory performance. The results showed that the inhibition efficiency (IE%) improved to 88.6 % with the addition of inhibitor concentration from 0.1 g/L to 3.0 g/L and that the corrosion rate drastically reduced from 56.91 mpy to 16.09 mpy. Furthermore, at a greater concentration (3.0 g/L), the Rct values rose from 61.42 Ω cm2 to 176.3 Ω cm2 thus, indicating that the inhibitor molecules were forming a protective film over the metallic surface. Scanning Electron Microscopy (SEM) provided visual evidence of surface morphology, revealing a smoother surface in the presence of the inhibitor, indicative of the protective film formed by the adsorption of organic molecules onto the steel surface. Theoretical calculations using the ωB97XD functional and def2svp basis set further supported the experimental findings, showing that the protonated form of C21H36O4 exhibited the highest interaction energy, correlating with its superior inhibition efficiency on the metal surface.
{"title":"Millettia aboensis leaves extract as eco-friendly corrosion inhibitor for mild steel in acidizing solution: From experimental to molecular level prediction","authors":"Fidelis E. Abeng , Benedict I. Ita , Magdalene E. Ikpi , Vitalis I. Chukwuike , Alexander I. Ikeuba , Moses M. Edim , Maduabuchi A. Chidiebere , Abhinay Thakur , Valentine C. Anadebe","doi":"10.1016/j.rineng.2024.102950","DOIUrl":"10.1016/j.rineng.2024.102950","url":null,"abstract":"<div><div>The development of environmentally friendly corrosion inhibitors is becoming more popular since conventional inhibitors are poisonous and non-biodegradable. The anti-corrosive effectiveness of <em>Millettia aboensis</em> leaves extract (MALE) has been assessed in this study using several methods, such as electrochemical measurements, X-ray Photoelectron spectroscopy and scanning electron microscopy on mild steel in acidic solution. Gas chromatography-mass spectrometry (GC-MS) analysis was combined with qualitative and quantitative phytochemical analysis to identify the phytochemicals linked to the activity of the <em>Millettia aboensis</em> extracts and identified key phytoconstituents such as Hexanedioic acid, Phenol derivatives, Octadecanoic acid, and Linolenic acid, which play significant roles in the extract's inhibitory performance. The results showed that the inhibition efficiency (IE%) improved to 88.6 % with the addition of inhibitor concentration from 0.1 g/L to 3.0 g/L and that the corrosion rate drastically reduced from 56.91 mpy to 16.09 mpy. Furthermore, at a greater concentration (3.0 g/L), the R<sub>ct</sub> values rose from 61.42 Ω cm<sup>2</sup> to 176.3 Ω cm<sup>2</sup> thus, indicating that the inhibitor molecules were forming a protective film over the metallic surface. Scanning Electron Microscopy (SEM) provided visual evidence of surface morphology, revealing a smoother surface in the presence of the inhibitor, indicative of the protective film formed by the adsorption of organic molecules onto the steel surface. Theoretical calculations using the ωB97XD functional and def2svp basis set further supported the experimental findings, showing that the protonated form of C<sub>21</sub>H<sub>36</sub>O<sub>4</sub> exhibited the highest interaction energy, correlating with its superior inhibition efficiency on the metal surface.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102950"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012052/pdfft?md5=f964376b1d3579b6d50eab9c506c190e&pid=1-s2.0-S2590123024012052-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A comprehensive understanding of the engineering characteristics of one-part slag-based geopolymer concrete (SBGC) is instrumental in promoting its widespread adoption and optimized design, improving construction practices, and advancing sustainability in the built environment. This study examined the workability, development of compressive strength, tensile strength, modulus of elasticity, and stress-strain behavior of one-part SBGC. The long-term compressive strength of SBGC, under both ambient curing and water curing conditions, has also been examined. Multiple combinations of mixtures were assessed, accounting for diverse factors such as activator ratio, aggregate size, water-to-binder ratio, curing conditions and activator types. This research also proposes new equations for predicting tensile strength and modulus of elasticity for one-part SBGC. The findings reveal that water-cured specimens demonstrate up to 43 % higher compressive strength and 52 % higher tensile strength compared to those cured under ambient conditions. Increasing the activator proportion in the mixture notably accelerates the early-stage development of compressive strength and SBGC's modulus of elasticity. Furthermore, one-part SBGC exhibits a long-term strength development that surpasses conventional concrete by over 20 %. In addition, the stress-strain behavior of SBGC reveals its inherent fragility, marked by near-perfect linear elasticity that abruptly transitions to complete and sudden collapse, distinguishing it from ordinary concrete. Microstructural analyses indicate that elevating the activator ratio reduces the presence of unreacted GGBFS particles and quartz in the mixture, thereby promoting the formation of gel.
{"title":"Mechanical properties and stress-strain relationship of slag-based one-part geopolymer concrete: A comparative study","authors":"Amgad Alhamoud, Hossein Tajmir Riahi, Abdolreza Ataei","doi":"10.1016/j.rineng.2024.102952","DOIUrl":"10.1016/j.rineng.2024.102952","url":null,"abstract":"<div><div>A comprehensive understanding of the engineering characteristics of one-part slag-based geopolymer concrete (SBGC) is instrumental in promoting its widespread adoption and optimized design, improving construction practices, and advancing sustainability in the built environment. This study examined the workability, development of compressive strength, tensile strength, modulus of elasticity, and stress-strain behavior of one-part SBGC. The long-term compressive strength of SBGC, under both ambient curing and water curing conditions, has also been examined. Multiple combinations of mixtures were assessed, accounting for diverse factors such as activator ratio, aggregate size, water-to-binder ratio, curing conditions and activator types. This research also proposes new equations for predicting tensile strength and modulus of elasticity for one-part SBGC. The findings reveal that water-cured specimens demonstrate up to 43 % higher compressive strength and 52 % higher tensile strength compared to those cured under ambient conditions. Increasing the activator proportion in the mixture notably accelerates the early-stage development of compressive strength and SBGC's modulus of elasticity. Furthermore, one-part SBGC exhibits a long-term strength development that surpasses conventional concrete by over 20 %. In addition, the stress-strain behavior of SBGC reveals its inherent fragility, marked by near-perfect linear elasticity that abruptly transitions to complete and sudden collapse, distinguishing it from ordinary concrete. Microstructural analyses indicate that elevating the activator ratio reduces the presence of unreacted GGBFS particles and quartz in the mixture, thereby promoting the formation of gel.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102952"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012076/pdfft?md5=8647d078686326cb4c26432070ffdf09&pid=1-s2.0-S2590123024012076-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.rineng.2024.102980
Behrooz Ruhani , Ali Basem , Haydar A.S. Aljaafari , Zahraa A. Hanoon , Shams Dheyaa Jumaah , Soheil Salahshour , Nafiseh Emami
Baghdadite is a monoclinic structure that is frequently used in biomedical applications and is a member of the calcium silicate zirconium group. In actual applications, the mechanical properties (MPs) of this atomic structure are of significant significance, among its other properties. Vacancy defects are one of the atomic phenomena that can affect the MP of Baghdadite. Molecular dynamic (MD) simulations were used to define the MP of Baghdadite-polycaprolactone-graphene nanocomposite (BN) in the presence of vacancy defects. The results of MD simulations show the excellent physical stability of BN with vacancy defects. Technically speaking, appropriate settings in the MD simulation box led to this result. Additionally, various parameters, including the stress-strain curve, Young's modulus (YM), and ultimate strength (US), were reported to explain the mechanical development of BN. In this simulation, vacancy defects to the initial compound at ratios ranging from 1 % to 10 % were introduced. Consequently, the YM of samples varied from 210.87 to 182.89 MPa, and the US decreased by 160.27 MPa. The calculated results show that the vacancy defects significantly reduced the mechanical strength of BN.
{"title":"Mechanical behavior of baghdadite-polycaprolactone-graphene nanocomposite for optimization of the bone treatment process in medical applications using molecular dynamics simulation","authors":"Behrooz Ruhani , Ali Basem , Haydar A.S. Aljaafari , Zahraa A. Hanoon , Shams Dheyaa Jumaah , Soheil Salahshour , Nafiseh Emami","doi":"10.1016/j.rineng.2024.102980","DOIUrl":"10.1016/j.rineng.2024.102980","url":null,"abstract":"<div><div>Baghdadite is a monoclinic structure that is frequently used in biomedical applications and is a member of the calcium silicate zirconium group. In actual applications, the mechanical properties (MPs) of this atomic structure are of significant significance, among its other properties. Vacancy defects are one of the atomic phenomena that can affect the MP of Baghdadite. Molecular dynamic (MD) simulations were used to define the MP of Baghdadite-polycaprolactone-graphene nanocomposite (BN) in the presence of vacancy defects. The results of MD simulations show the excellent physical stability of BN with vacancy defects. Technically speaking, appropriate settings in the MD simulation box led to this result. Additionally, various parameters, including the stress-strain curve, Young's modulus (YM), and ultimate strength (US), were reported to explain the mechanical development of BN. In this simulation, vacancy defects to the initial compound at ratios ranging from 1 % to 10 % were introduced. Consequently, the YM of samples varied from 210.87 to 182.89 MPa, and the US decreased by 160.27 MPa. The calculated results show that the vacancy defects significantly reduced the mechanical strength of BN.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102980"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012350/pdfft?md5=be155ef260f6d87fd3701a1658a94e0f&pid=1-s2.0-S2590123024012350-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.rineng.2024.102963
Ardalan B. Hussein , Diyari B. Hussein
The use of back-to-back built-up C-section beams is becoming increasingly common in CFS construction due to their cost-effectiveness and enhanced load-carrying capacity, making them suitable for longer beam spans and convenient for transportation. These built-up sections are utilized in wall studs, truss components, and floor joists, with intermediate screw fasteners placed at specific intervals to prevent the separate bowing of channels. This study reveals a ratio of 1.003 between experimental findings and finite element analysis results, and 1.002 between experimental findings and direct strength method results, indicating a strong correlation between experimental data from nonlinear finite element analysis and predictions based on the American Iron and Steel Institute and Australian and New Zealand Standards, particularly in predicting the flexural buckling strength of beam specimens. Furthermore, ongoing research is investigating the impact of screw spacing on flexural strength. This study presents results from 175 finite element tests, evaluating seven distinct cross-sections with twelve unique screw spacings. These spacings correspond to the half wavelength of local, distortional, and global buckling, divided by values from one to four. It was found that screw spacing based on half the local buckling half-wavelength along the centerline of the webs increased the critical global buckling moment capacity and the nominal flexural strength by 56 % and 27 %, respectively. For double-lane screws with the same spacing, these increases were even more substantial, reaching 65 % and 31 %, respectively. Economically, the recommended spacing for single-lane screws is half the local buckling half-wavelength.
{"title":"Structural behavior of built-up I-shaped CFS beams","authors":"Ardalan B. Hussein , Diyari B. Hussein","doi":"10.1016/j.rineng.2024.102963","DOIUrl":"10.1016/j.rineng.2024.102963","url":null,"abstract":"<div><div>The use of back-to-back built-up C-section beams is becoming increasingly common in CFS construction due to their cost-effectiveness and enhanced load-carrying capacity, making them suitable for longer beam spans and convenient for transportation. These built-up sections are utilized in wall studs, truss components, and floor joists, with intermediate screw fasteners placed at specific intervals to prevent the separate bowing of channels. This study reveals a ratio of 1.003 between experimental findings and finite element analysis results, and 1.002 between experimental findings and direct strength method results, indicating a strong correlation between experimental data from nonlinear finite element analysis and predictions based on the American Iron and Steel Institute and Australian and New Zealand Standards, particularly in predicting the flexural buckling strength of beam specimens. Furthermore, ongoing research is investigating the impact of screw spacing on flexural strength. This study presents results from 175 finite element tests, evaluating seven distinct cross-sections with twelve unique screw spacings. These spacings correspond to the half wavelength of local, distortional, and global buckling, divided by values from one to four. It was found that screw spacing based on half the local buckling half-wavelength along the centerline of the webs increased the critical global buckling moment capacity and the nominal flexural strength by 56 % and 27 %, respectively. For double-lane screws with the same spacing, these increases were even more substantial, reaching 65 % and 31 %, respectively. Economically, the recommended spacing for single-lane screws is half the local buckling half-wavelength.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102963"},"PeriodicalIF":6.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024012180/pdfft?md5=1d27c322873b0b4181d6dd1752445056&pid=1-s2.0-S2590123024012180-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.rineng.2024.102931
Mahyar Arabani , Mohammad Mahdi Shalchian , Maryam Majd Rahimabadi
Since clayey soils naturally present low mechanical strength, they pose direct challenges for engineering applications. Finding appropriate soil stabilizers to address the challenges posed by clayey soils is crucial for ensuring that the soil meets the necessary geotechnical requirements and fulfills economic and environmental issues. To this end, this research uses several stabilizers and techniques in clayey soils to improve their suitability for construction. The main objective of this study is to assess the use of wheat fiber and nanobentonite (NB) in soil stabilization, estimate their behavior in practices, outline their obstacles and potential for soil improvement, and consider their ecological and financial effects. This research also evaluates the behavior of the soil by incorporating NB (0.4, 0.8, and 1.2 %) as a stabilizing agent. For this purpose, the randomly dispersed wheat fibers as a reinforcing agent at different dosages and lengths (0.3, 0.6, 0.9 %, and 5, 10, and 15 mm) were combined to the soil matrix. The soil was characterized by conducting compaction, unconfined compressive strength (UCS), direct shear (DS), California bearing ratio (CBR), indirect tensile strength (ITS), freezing-thawing (F-T) tests, and microstructural analysis. The data were used to assess the effect of wheat fiber and NB on the soil's geotechnical properties. The results revealed that incorporating 0.8 % NB into the soil led to the best enhancement in compressive strength. This improvement is attributed to the dehydration and formation of a viscous-like film between the soil particles. In addition, 0.6 % fibers with a length of 15 mm increased the interaction and bonding forces between the particles of soil, resulting in a maximum increase in compressive strength. Combining fibers and NB improved the shear strength, tensile strength, and bearing capacity. Besides, the stabilized soil exhibited superior resistance to freezing-thawing cycles compared to the unreinforced clay. Overall, the results indicate that using wheat fibers and NB is a cost-effective and eco-friendly solution for stabilizing clay subgrades.
由于粘性土的机械强度天然较低，因此给工程应用带来了直接挑战。找到合适的土壤稳定剂来应对粘性土所带来的挑战，对于确保土壤满足必要的岩土工程要求并解决经济和环境问题至关重要。为此，本研究在粘性土中使用了几种稳定剂和技术，以提高其施工适用性。本研究的主要目的是评估小麦纤维和纳米膨润土（NB）在土壤稳定中的应用，估计其在实践中的表现，概述其在土壤改良中的障碍和潜力，并考虑其生态和经济影响。本研究还评估了添加 NB（0.4%、0.8% 和 1.2%）作为稳定剂的土壤行为。为此，在土壤基质中加入了不同剂量和长度（0.3%、0.6%、0.9%，以及 5 毫米、10 毫米和 15 毫米）的随机分散小麦纤维作为加固剂。通过压实、无侧限抗压强度 (UCS)、直接剪切 (DS)、加州承载比 (CBR)、间接抗拉强度 (ITS)、冻融 (F-T) 试验和微观结构分析对土壤进行了表征。这些数据用于评估小麦纤维和 NB 对土壤岩土特性的影响。结果表明，在土壤中加入 0.8 % 的 NB 可最大程度地提高抗压强度。这种改善归因于土壤颗粒之间的脱水和粘性薄膜的形成。此外，长度为 15 毫米的 0.6 % 纤维增加了土壤颗粒之间的相互作用力和结合力，从而使抗压强度得到最大程度的提高。纤维与 NB 的结合提高了剪切强度、抗拉强度和承载能力。此外，与未加固的粘土相比，加固后的土壤表现出更强的抗冻融循环能力。总之，研究结果表明，使用小麦纤维和 NB 是稳定粘土基层的一种经济、环保的解决方案。
{"title":"Use of wheat fiber and nanobentonite to stabilize clay subgrades","authors":"Mahyar Arabani , Mohammad Mahdi Shalchian , Maryam Majd Rahimabadi","doi":"10.1016/j.rineng.2024.102931","DOIUrl":"10.1016/j.rineng.2024.102931","url":null,"abstract":"<div><div>Since clayey soils naturally present low mechanical strength, they pose direct challenges for engineering applications. Finding appropriate soil stabilizers to address the challenges posed by clayey soils is crucial for ensuring that the soil meets the necessary geotechnical requirements and fulfills economic and environmental issues. To this end, this research uses several stabilizers and techniques in clayey soils to improve their suitability for construction. The main objective of this study is to assess the use of wheat fiber and nanobentonite (NB) in soil stabilization, estimate their behavior in practices, outline their obstacles and potential for soil improvement, and consider their ecological and financial effects. This research also evaluates the behavior of the soil by incorporating NB (0.4, 0.8, and 1.2 %) as a stabilizing agent. For this purpose, the randomly dispersed wheat fibers as a reinforcing agent at different dosages and lengths (0.3, 0.6, 0.9 %, and 5, 10, and 15 mm) were combined to the soil matrix. The soil was characterized by conducting compaction, unconfined compressive strength (UCS), direct shear (DS), California bearing ratio (CBR), indirect tensile strength (ITS), freezing-thawing (F-T) tests, and microstructural analysis. The data were used to assess the effect of wheat fiber and NB on the soil's geotechnical properties. The results revealed that incorporating 0.8 % NB into the soil led to the best enhancement in compressive strength. This improvement is attributed to the dehydration and formation of a viscous-like film between the soil particles. In addition, 0.6 % fibers with a length of 15 mm increased the interaction and bonding forces between the particles of soil, resulting in a maximum increase in compressive strength. Combining fibers and NB improved the shear strength, tensile strength, and bearing capacity. Besides, the stabilized soil exhibited superior resistance to freezing-thawing cycles compared to the unreinforced clay. Overall, the results indicate that using wheat fibers and NB is a cost-effective and eco-friendly solution for stabilizing clay subgrades.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102931"},"PeriodicalIF":6.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024011861/pdfft?md5=099b7ad26b5cada7b498624ea9c4b75b&pid=1-s2.0-S2590123024011861-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.rineng.2024.102908
Gergő Békési , Lilla Barancsuk , Bálint Hartmann
In the past decade, distribution system state estimation has become a crucial topic in power system research due to the increasing importance of distribution networks amidst the decline of centralized energy production. This paper addresses a gap in the literature regarding the application of modern hyperparameter optimization techniques in low-voltage distribution system state estimation using deep neural networks. In particular, it demonstrates the use of the Tree-structured Parzen Estimator algorithm, which is a Bayesian hyperparameter optimization method, for distribution system state estimation on real Hungarian low-voltage networks. The study uses data from four real-life low-voltage supply areas in Hungary, which were modeled to address the challenges in obtaining network information. Compared to traditional methods like the weighted least squares method, the Tree-structured Parzen Estimator algorithm significantly improves the accuracy of the voltage amplitude and angle estimations, reducing the relative error by 14–73%. Additionally, it is shown that TPE outperforms simpler methods like Random Search in hyperparameter optimization. The results also reveal connections between the distribution system size and optimal hyperparameters, such as batch size, learning rate, and hidden layer configuration. The proposed non-iterative algorithm, combined with the parallel computation capabilities of deep neural networks utilizing GPU, resulted in four orders of magnitude improvement in runtime. These advancements make the proposed approach a valuable tool for renewable energy integration planning and real-time monitoring, highlighting its potential for practical applications in the power industry.
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In order to achieve a sustainable, low-carbon energy future, it is necessary to develop innovative and integrated solutions. However, one of the main obstacles to the advancement of renewable energy is storage. With this in mind, hybrid systems combining solar energy and hydrogen production have great potential. This article focuses on the evaluation of a solar PV/T (photovoltaic-thermal) system coupled with an electrolyser for the joint production of hydrogen and heat. Simulations are performed in MATLAB. The analysis reveals that with PV/T power supply, the production potential is estimated at 179.6 W and 551.9 W respectively for electrical and thermal power. An in-depth study aimed at optimizing the system by evaluating the quality of the energy used in the water electrolysis process makes it possible to analyze the effect of certain operating parameters. With a water flow of 5.7 , a current density of 200 mA/ and an electrolyzer temperature of 60 °C, the monthly production of hydrogen and oxygen reaches the maximum values of 4.85 and 2.42 respectively. This led to a maximum exergy efficiency of 57.8 %. This study demonstrates the linearity between hydrogen production and current density which at high density reduces exergy performance.
{"title":"Evaluation of the hydrogen/oxygen and thermoelectric production of a hybrid solar PV/T-electrolyzer system","authors":"Armel Zambou Kenfack , Modeste Kameni Nematchoua , Venant Sorel Chara-Dackou , Elie Simo","doi":"10.1016/j.rineng.2024.102920","DOIUrl":"10.1016/j.rineng.2024.102920","url":null,"abstract":"<div><div>In order to achieve a sustainable, low-carbon energy future, it is necessary to develop innovative and integrated solutions. However, one of the main obstacles to the advancement of renewable energy is storage. With this in mind, hybrid systems combining solar energy and hydrogen production have great potential. This article focuses on the evaluation of a solar PV/T (photovoltaic-thermal) system coupled with an electrolyser for the joint production of hydrogen and heat. Simulations are performed in MATLAB. The analysis reveals that with PV/T power supply, the production potential is estimated at 179.6 W and 551.9 W respectively for electrical and thermal power. An in-depth study aimed at optimizing the system by evaluating the quality of the energy used in the water electrolysis process makes it possible to analyze the effect of certain operating parameters. With a water flow of 5.7 <span><math><mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span> <span><math><mrow><msup><mi>m</mi><mn>3</mn></msup><mo>/</mo><mi>h</mi></mrow></math></span>, a current density of 200 mA/ <span><math><mrow><msup><mtext>cm</mtext><mn>2</mn></msup></mrow></math></span> and an electrolyzer temperature of 60 °C, the monthly production of hydrogen and oxygen reaches the maximum values of 4.85 <span><math><mrow><msup><mi>m</mi><mn>3</mn></msup></mrow></math></span> and 2.42 <span><math><mrow><msup><mi>m</mi><mn>3</mn></msup></mrow></math></span> respectively. This led to a maximum exergy efficiency of 57.8 %. This study demonstrates the linearity between hydrogen production and current density which at high density reduces exergy performance.</div></div>","PeriodicalId":36919,"journal":{"name":"Results in Engineering","volume":"24 ","pages":"Article 102920"},"PeriodicalIF":6.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590123024011757/pdfft?md5=5ca2276cfaf8d3c6b330c6fdc5764ebb&pid=1-s2.0-S2590123024011757-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.rineng.2024.102942
Vijayakumar S, Sudhakar N
This research article focuses on designing and implementing a single ended primary inductor converter (SEPIC) for an AC-DC converter, followed by an electric vehicle (EV) charger. It improves the high-power factor at the AC supply with minimum harmonic distortion. The Golden Eagle optimization techniques are adapted to optimize the tuning of Proportional-Integral (PI) and Linear Quadratic Regulator (LQR) controller parameters for better converter performance. The optimization is designed based on the eagle knowledge of hunting methods at various angles of spiral trajectories in capturing the animal. The SEPIC converter is designed and derived from the state space model by state space averaging, and the reduced model is obtained through the moment matching method to reduce computational complexity. The Golden Eagle Optimize the parameters of KP and KI of the PI controller and weighing matrix Q of the linear quadratic controller. The fitness function of the proposed optimization is the sum of the Integral Absolute error (IAE) and Integral Square error (ISE). The proposed optimization is implemented using MATLAB/SIMULINK software, and the simulation outcomes demonstrate an improved settling time, fast recovery against input and output variations, Total Harmonic Distortion (THD) of 1.75 %, and enhanced stability.
本文的研究重点是为交直流转换器设计和实现单端初级电感转换器（SEPIC），然后再用于电动汽车（EV）充电器。它以最小的谐波失真提高了交流电源的高功率因数。金鹰优化技术适用于优化比例积分（PI）和线性二次调节器（LQR）控制器参数的调整，以获得更好的转换器性能。优化设计基于老鹰在捕捉动物时不同角度螺旋轨迹的狩猎方法知识。通过状态空间平均法设计并推导出 SEPIC 转换器的状态空间模型，并通过矩匹配法获得简化模型，以降低计算复杂度。金鹰优化 PI 控制器的 KP 和 KI 参数以及线性二次控制器的权重矩阵 Q。拟议优化的拟合函数为积分绝对误差（IAE）和积分平方误差（ISE）之和。使用 MATLAB/SIMULINK 软件实现了拟议的优化，仿真结果表明，稳定时间得到了改善，输入和输出变化得到了快速恢复，总谐波失真 (THD) 为 1.75 %，稳定性得到了增强。
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