Ibtissem Allali, L. Belagraa, M. Beddar, O. Kessal
The formulation of an innovative concrete that meets the requirements of a self-compacting concrete (SCC), with acceptable performance in terms of rheology in the fresh state; good fluidity, ease of placing, without segregation as well as good mechanical strength and durability at hardened state has become of great research interest for the last decades. Numerous studies have shown the favorable effects of limestone fillers on the SCC properties. This study aims at investigating the effect of inert mineral addition of limestone fillers with dosages of 10% and 20% grinded to different fine nesses 2000, 3000 and 4000 cm2/g on the physico-mechanical properties of a fresh self-placing concrete using slump, the L-box and the sieve stability tests. Also, the means of destructive and non-destructive tests (NDT) methods to the assessment of the mechanical performances of SCC at hardened state were used. The use of experiment factorial design method allows us to have behavior laws to predict the mechanical strength response when combined with (NDT) according to a numerical model in such study. Hence, a numerical modeling of mechanical response could be derived by such statistical analysis in regards to the effects of factors and their interaction. The results obtained showed that the incorporation of limestone filler in the composition of the SCC improves the fluidity with limited segregation, as well as the good mechanical performances (resistance to compression and flexion). The numerical modeling of the predicted compressive strength response, in particular at the age of 28 days, is judged to be with an acceptable determined coefficient R2 equal to 0.994.
{"title":"Characterization and Modeling Using Non-Destructive Test (NDT) and Experimental Design Methods of a Self Compacting Concrete (SCC) Based on Mineral Additions","authors":"Ibtissem Allali, L. Belagraa, M. Beddar, O. Kessal","doi":"10.18280/acsm.460204","DOIUrl":"https://doi.org/10.18280/acsm.460204","url":null,"abstract":"The formulation of an innovative concrete that meets the requirements of a self-compacting concrete (SCC), with acceptable performance in terms of rheology in the fresh state; good fluidity, ease of placing, without segregation as well as good mechanical strength and durability at hardened state has become of great research interest for the last decades. Numerous studies have shown the favorable effects of limestone fillers on the SCC properties. This study aims at investigating the effect of inert mineral addition of limestone fillers with dosages of 10% and 20% grinded to different fine nesses 2000, 3000 and 4000 cm2/g on the physico-mechanical properties of a fresh self-placing concrete using slump, the L-box and the sieve stability tests. Also, the means of destructive and non-destructive tests (NDT) methods to the assessment of the mechanical performances of SCC at hardened state were used. The use of experiment factorial design method allows us to have behavior laws to predict the mechanical strength response when combined with (NDT) according to a numerical model in such study. Hence, a numerical modeling of mechanical response could be derived by such statistical analysis in regards to the effects of factors and their interaction. The results obtained showed that the incorporation of limestone filler in the composition of the SCC improves the fluidity with limited segregation, as well as the good mechanical performances (resistance to compression and flexion). The numerical modeling of the predicted compressive strength response, in particular at the age of 28 days, is judged to be with an acceptable determined coefficient R2 equal to 0.994.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74248840","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}
D. Kerdoud, Faouzia Benkafada, N. Boussouf, C. Benhamideche
Our research involves the preparation of transition metal nitrides of the composition Mn4N, NbN, Mo2N, TaN and ZrN. The synthesis of Li3N binary alkali metal nitride was also part of this work. Simple and cost-effective methods with relatively low impact on the environment have been privileged in the selection. The experimental work has focused on determining the optimum conditions of synthesis and the convenient high yield route to the desired nitrides, and ultimately improvement of the properties of the final materials. All samples were characterised by X-ray powder diffraction. Their structures will be discussed in more detail here. Optical band gap has been calculated from diffuse reflectance measurements. The air sensitivity of the nitrides was also probed.
{"title":"Nitride Materials: Synthesis, Crystal Structures, and Optical Properties","authors":"D. Kerdoud, Faouzia Benkafada, N. Boussouf, C. Benhamideche","doi":"10.18280/acsm.460206","DOIUrl":"https://doi.org/10.18280/acsm.460206","url":null,"abstract":"Our research involves the preparation of transition metal nitrides of the composition Mn4N, NbN, Mo2N, TaN and ZrN. The synthesis of Li3N binary alkali metal nitride was also part of this work. Simple and cost-effective methods with relatively low impact on the environment have been privileged in the selection. The experimental work has focused on determining the optimum conditions of synthesis and the convenient high yield route to the desired nitrides, and ultimately improvement of the properties of the final materials. All samples were characterised by X-ray powder diffraction. Their structures will be discussed in more detail here. Optical band gap has been calculated from diffuse reflectance measurements. The air sensitivity of the nitrides was also probed.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74386184","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}
Ayoub Laoucine, M. Bachene, S. Rechak, G. Lorenzini, N. Kaid, Y. Menni
In this work, a numerical study of the perforation of 6061-T6 aluminum, Titanium Ti6Al4V and stainless steel (Nitronic33) plates by a rigid flat nose punch is carried out. The Johnson-Cook model was used to define the behavior of the material constituting the plate. This homogeneous behavior was coupled with the Johnson-Cook rupture criterion to completely predict the perforation process. Initially, the present results are validated by comparing them with the results reported in the literature, including those obtained from experimental work. Thereafter, several numerical parametric analyses are performed to investigate the behavior of these metal plates depending on the maximum breaking force, the temperature in the perforated plates, the kinetic energy, the clearance on the shape of the sheared edge, and the dimensional accuracy of the plates.
{"title":"Perforation Analysis by Punching of Metal Sheets","authors":"Ayoub Laoucine, M. Bachene, S. Rechak, G. Lorenzini, N. Kaid, Y. Menni","doi":"10.18280/acsm.460101","DOIUrl":"https://doi.org/10.18280/acsm.460101","url":null,"abstract":"In this work, a numerical study of the perforation of 6061-T6 aluminum, Titanium Ti6Al4V and stainless steel (Nitronic33) plates by a rigid flat nose punch is carried out. The Johnson-Cook model was used to define the behavior of the material constituting the plate. This homogeneous behavior was coupled with the Johnson-Cook rupture criterion to completely predict the perforation process. Initially, the present results are validated by comparing them with the results reported in the literature, including those obtained from experimental work. Thereafter, several numerical parametric analyses are performed to investigate the behavior of these metal plates depending on the maximum breaking force, the temperature in the perforated plates, the kinetic energy, the clearance on the shape of the sheared edge, and the dimensional accuracy of the plates.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90190446","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}
Naga Venkata Sai Ram Yellapragada, S. Devarakonda, Kondala Rao Dasari, Naga Sai Rama Krishna Thati, Jaya Sai Abhaya Veeranjaneya Vara Prasad Alapati
In recent past conventional monolithic materials are replaced with fiber reinforced polymer composite materials due to their high specific strength. The current study focused on dry-sliding wear behaviour of carbon fiber reinforced polyester (CFRP) composites using a pin-on-disc tribometer. The two output responses selected were rate of wear and frictional force with respect to controlled variables using the Taguchi L16 OA (Orthogonal Array). In order to assess the best optimal conditions GRA technique has been used in the study. The effectiveness of entropy weights on the optimal result has been carried out in support with ANOVA studies. In GRA analysis, the combined effect of wear and frictional force is considered and the optimal conditional identified in two ways namely equal weightage method (EWM) and entropy based weightage method (EBWM). While considering EWM method the optimal condition obtained is S1 L4 D3 R4 whereas in EBWM the optimal solution obtained is S1 L4 D1 R4. This shows because of the uneven weights generated by EBWM method there is a change in optimal solution in comparison with EWM method.
{"title":"Effectiveness of Shannon Entropy Weight Method on Wear Behaviour of Polyester/Carbon Fibre Composites Using GRA","authors":"Naga Venkata Sai Ram Yellapragada, S. Devarakonda, Kondala Rao Dasari, Naga Sai Rama Krishna Thati, Jaya Sai Abhaya Veeranjaneya Vara Prasad Alapati","doi":"10.18280/acsm.460102","DOIUrl":"https://doi.org/10.18280/acsm.460102","url":null,"abstract":"In recent past conventional monolithic materials are replaced with fiber reinforced polymer composite materials due to their high specific strength. The current study focused on dry-sliding wear behaviour of carbon fiber reinforced polyester (CFRP) composites using a pin-on-disc tribometer. The two output responses selected were rate of wear and frictional force with respect to controlled variables using the Taguchi L16 OA (Orthogonal Array). In order to assess the best optimal conditions GRA technique has been used in the study. The effectiveness of entropy weights on the optimal result has been carried out in support with ANOVA studies. In GRA analysis, the combined effect of wear and frictional force is considered and the optimal conditional identified in two ways namely equal weightage method (EWM) and entropy based weightage method (EBWM). While considering EWM method the optimal condition obtained is S1 L4 D3 R4 whereas in EBWM the optimal solution obtained is S1 L4 D1 R4. This shows because of the uneven weights generated by EBWM method there is a change in optimal solution in comparison with EWM method.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87439398","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}
High performance concrete (HPC) has several advantages in building construction that cannot be achieved using conventional concrete in terms of strength durability, resistance to chemical attack, and workability of high performance concrete are high. The introduction of fillers and additives contributed to the improvement of high-performance concrete (HPC), other parameters also influence the performance of these HPCs, coarse aggregate fraction is known to strongly influence both fresh and hardened concrete’s properties. Consequently, selection of both content and particle size distribution for (HPC) mixture is an important issue regarding the predicted performance of concrete. For to make concrete more improvement , the porosity of the granular skeleton as well as the rheology of our HPC, 3/8 fraction of rolled gravel with smooth and rounded surfaces was introduced, in substitution for the crushed gravel of the same fraction , by testing various combinations of fractions 3/8 of rolled gravel and fraction 8/15 of crushed gravel in the present study, and based on previous results obtained the combinations 35,40 and 45% fraction 3/8 of rolled gravel and 65 , 60 and 55% fraction 8/15 of crushed gravel (binary granular system) respectively, gives a minimal porosity . Super plasticizer and four percentages of pozzolan were experimented. Compressive strength function of coarse aggregate was determined at 7, 14 and 28 days. Results have revealed that the mixtures with modified granule size distribution system ,1.5% of superplasticizer and 5% by weight of pozzolan allow an improvement in the compressive strength of 35.1% relative to the control concrete.
{"title":"Impact of Rolled and Crushed Aggregate with Natural Pozzolan on the Behavior of HPC","authors":"S. Zitouni, M. Maza, N. Tebbal, Z. Rahmouni","doi":"10.18280/acsm.460106","DOIUrl":"https://doi.org/10.18280/acsm.460106","url":null,"abstract":"High performance concrete (HPC) has several advantages in building construction that cannot be achieved using conventional concrete in terms of strength durability, resistance to chemical attack, and workability of high performance concrete are high. The introduction of fillers and additives contributed to the improvement of high-performance concrete (HPC), other parameters also influence the performance of these HPCs, coarse aggregate fraction is known to strongly influence both fresh and hardened concrete’s properties. Consequently, selection of both content and particle size distribution for (HPC) mixture is an important issue regarding the predicted performance of concrete. For to make concrete more improvement , the porosity of the granular skeleton as well as the rheology of our HPC, 3/8 fraction of rolled gravel with smooth and rounded surfaces was introduced, in substitution for the crushed gravel of the same fraction , by testing various combinations of fractions 3/8 of rolled gravel and fraction 8/15 of crushed gravel in the present study, and based on previous results obtained the combinations 35,40 and 45% fraction 3/8 of rolled gravel and 65 , 60 and 55% fraction 8/15 of crushed gravel (binary granular system) respectively, gives a minimal porosity . Super plasticizer and four percentages of pozzolan were experimented. Compressive strength function of coarse aggregate was determined at 7, 14 and 28 days. Results have revealed that the mixtures with modified granule size distribution system ,1.5% of superplasticizer and 5% by weight of pozzolan allow an improvement in the compressive strength of 35.1% relative to the control concrete.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90064423","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}
Mihoub Medkour, N. Kaid, H. Ameur, Chutarat Tearnbucha, W. Sudsutad, G. Lorenzini, Hijaz Ahmad, Y. Menni
The current work investigates the efficiency of a Direct Methanol Fuel Cell (DMFC) by using COMSOL. The set-up model takes into consideration the electrochemical kinetics and chemical reactions. The anode catalyst layers are a main element in the PEM fuel cell; their porosity significantly affects the fuel cell efficiency. We focus on the impact of catalytic layers porosity on the battery efficiency. As claimed by the results, the porosity of catalytic layer greatly affects the performance of the battery. In addition, better output performance of µDMFC may be obtained when the catalytic layer porosity is chosen as εACL=0.009-0.1. The distributions of methanol, carbon dioxide, water, oxygen, polarization, and the current density are plotted to highlight the impact of porosity on the global performances.
{"title":"Study of the Effect of ACL Anode Catalytic Layer Porosity on the Efficiency of a Direct Methanol Fuel Cell","authors":"Mihoub Medkour, N. Kaid, H. Ameur, Chutarat Tearnbucha, W. Sudsutad, G. Lorenzini, Hijaz Ahmad, Y. Menni","doi":"10.18280/acsm.460107","DOIUrl":"https://doi.org/10.18280/acsm.460107","url":null,"abstract":"The current work investigates the efficiency of a Direct Methanol Fuel Cell (DMFC) by using COMSOL. The set-up model takes into consideration the electrochemical kinetics and chemical reactions. The anode catalyst layers are a main element in the PEM fuel cell; their porosity significantly affects the fuel cell efficiency. We focus on the impact of catalytic layers porosity on the battery efficiency. As claimed by the results, the porosity of catalytic layer greatly affects the performance of the battery. In addition, better output performance of µDMFC may be obtained when the catalytic layer porosity is chosen as εACL=0.009-0.1. The distributions of methanol, carbon dioxide, water, oxygen, polarization, and the current density are plotted to highlight the impact of porosity on the global performances.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75458673","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}
Jocelyn P. Doronio, J. R. Salazar, J. Monserate, Benyl John A. Arevalo, P. Eugenio, M. M. Sarong
Garlic contains various polyphenolic compounds such as anthocyanin, a bioactive, water-soluble compound generally known for its remarkable health-enhancing properties. However, it is chemically unstable and easily degrades due to various environmental conditions (temperature, pH, presence of oxygen and light, etc.) in addition to its low bioavailability due to fast metabolization and low absorption in the body. Therefore, a nanoencapsulation strategy is essential to address these limitations. In this work, anthocyanin extraction from FBG (Ilocos variety) with 85% acidified ethanol and its encapsulation using the chitosan-alginate nanoparticle system via pre-gelation and polyelectrolyte complex formation were demonstrated. Anthocyanin-loaded chitosan-alginate nanocapsules were characterized in terms of structural features, particle size, morphology, encapsulation efficiency, total phenolic content (TPC), and radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The obtained anthocyanin-loaded nanocapsules have small particle sizes ranging from 50.7 nm to 92.0 nm with high encapsulation efficiency (T3: 78.82%, T2: 68.18%, T1: 65.77%). Results showed that a higher initial concentration of anthocyanin extract promotes higher encapsulation efficiency. Antioxidant activity of the nanocapsules showed low phenolic content (0.11 mg GAE/g) but high DPPH scavenging activity (14.02 mg AAE/g). The chitosan-alginate complex has successfully encapsulated the anthocyanin from fermented black garlic.
{"title":"Nanoencapsulation of Anthocyanin Extract from Fermented Black Garlic (FBG) Based on Biocompatible Polymeric Materials","authors":"Jocelyn P. Doronio, J. R. Salazar, J. Monserate, Benyl John A. Arevalo, P. Eugenio, M. M. Sarong","doi":"10.18280/acsm.460105","DOIUrl":"https://doi.org/10.18280/acsm.460105","url":null,"abstract":"Garlic contains various polyphenolic compounds such as anthocyanin, a bioactive, water-soluble compound generally known for its remarkable health-enhancing properties. However, it is chemically unstable and easily degrades due to various environmental conditions (temperature, pH, presence of oxygen and light, etc.) in addition to its low bioavailability due to fast metabolization and low absorption in the body. Therefore, a nanoencapsulation strategy is essential to address these limitations. In this work, anthocyanin extraction from FBG (Ilocos variety) with 85% acidified ethanol and its encapsulation using the chitosan-alginate nanoparticle system via pre-gelation and polyelectrolyte complex formation were demonstrated. Anthocyanin-loaded chitosan-alginate nanocapsules were characterized in terms of structural features, particle size, morphology, encapsulation efficiency, total phenolic content (TPC), and radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The obtained anthocyanin-loaded nanocapsules have small particle sizes ranging from 50.7 nm to 92.0 nm with high encapsulation efficiency (T3: 78.82%, T2: 68.18%, T1: 65.77%). Results showed that a higher initial concentration of anthocyanin extract promotes higher encapsulation efficiency. Antioxidant activity of the nanocapsules showed low phenolic content (0.11 mg GAE/g) but high DPPH scavenging activity (14.02 mg AAE/g). The chitosan-alginate complex has successfully encapsulated the anthocyanin from fermented black garlic.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87948500","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}
Abderrachid Amriou, H. Ziani, Sadek Deboucha, M. Bencheikh
Concrete is the most widely used material in the field of civil engineering. In order to obtain a strong and durable concrete, it is necessary to study the various parameters entering into its formulation. Mainly the elements forming the concrete skeleton, in particular the gravel content. The transfer of water into concrete directly affects its durability. This transfer is linked to the porous structure and to the continuity of the pores in the concrete. This research studies the effect of gravel content on compressive strength, porosity accessible to water, depth of water penetration and ultrasonic velocity of concrete samples. The study includes 15 types of concrete made by varying the gravel-sand ratio (G/S), 0, 1, 1.5, 2 and 2.5. The cement dosage is taken equal to 150, 250 and 350 Kg/m3. The tests are carried out on cubic samples 10x10x10 cm3 and 15x15x15 cm3 after storage in water for 28 days. The experimental results obtained show that the gravel-sand ratio (G/S) affects the mechanical strength and the porous structure of concrete. Increasing the gravel content in concrete leads to an increase in mechanical strength and ultrasonic speed. However, a high gravel content results in a reduction in the porosity accessible to water and the depth of water penetration.
{"title":"Effect of Gravel Content on Mechanical Performance and Porous Structure of Concrete","authors":"Abderrachid Amriou, H. Ziani, Sadek Deboucha, M. Bencheikh","doi":"10.18280/acsm.460103","DOIUrl":"https://doi.org/10.18280/acsm.460103","url":null,"abstract":"Concrete is the most widely used material in the field of civil engineering. In order to obtain a strong and durable concrete, it is necessary to study the various parameters entering into its formulation. Mainly the elements forming the concrete skeleton, in particular the gravel content. The transfer of water into concrete directly affects its durability. This transfer is linked to the porous structure and to the continuity of the pores in the concrete. This research studies the effect of gravel content on compressive strength, porosity accessible to water, depth of water penetration and ultrasonic velocity of concrete samples. The study includes 15 types of concrete made by varying the gravel-sand ratio (G/S), 0, 1, 1.5, 2 and 2.5. The cement dosage is taken equal to 150, 250 and 350 Kg/m3. The tests are carried out on cubic samples 10x10x10 cm3 and 15x15x15 cm3 after storage in water for 28 days. The experimental results obtained show that the gravel-sand ratio (G/S) affects the mechanical strength and the porous structure of concrete. Increasing the gravel content in concrete leads to an increase in mechanical strength and ultrasonic speed. However, a high gravel content results in a reduction in the porosity accessible to water and the depth of water penetration.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78324119","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}
N. Tallah, A. Mabrouki, A. Boulaouad, M. Khemissa, A. Bouaicha
Recent studies of retaining walls include experimental studies, numerical analysis and analytical models. Although active earth pressure against retaining structures has received much attention, the evaluation of active earth pressure of backfill when loaded by a strip foundation, has been slightly studied. This paper studies the effect of a strip load on the active pressure force and the distribution of the horizontal stresses on a rigid wall, using a finite element limit analysis. The strip loading is located at different distances from the vertical face of the wall. The OptumG2 code is used to analyze the effect of width of strip surcharge (soil-wall), interface friction angle and soil internal friction angle. New interesting results are demonstrated and presented here: the dependency of the active earth pressure coefficient on both position and width of the strip load, in one hand, and the effect of the internal friction angle of the soil, the soil-wall interface, and the position of the strip loading on the failure mechanism, in the other hand.
{"title":"Limit Analyses of the Active Earth Pressure on Rigid Retaining Walls under Strip Loading on Backfills","authors":"N. Tallah, A. Mabrouki, A. Boulaouad, M. Khemissa, A. Bouaicha","doi":"10.18280/acsm.460104","DOIUrl":"https://doi.org/10.18280/acsm.460104","url":null,"abstract":"Recent studies of retaining walls include experimental studies, numerical analysis and analytical models. Although active earth pressure against retaining structures has received much attention, the evaluation of active earth pressure of backfill when loaded by a strip foundation, has been slightly studied. This paper studies the effect of a strip load on the active pressure force and the distribution of the horizontal stresses on a rigid wall, using a finite element limit analysis. The strip loading is located at different distances from the vertical face of the wall. The OptumG2 code is used to analyze the effect of width of strip surcharge (soil-wall), interface friction angle and soil internal friction angle. New interesting results are demonstrated and presented here: the dependency of the active earth pressure coefficient on both position and width of the strip load, in one hand, and the effect of the internal friction angle of the soil, the soil-wall interface, and the position of the strip loading on the failure mechanism, in the other hand.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78323945","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}
A. Latrous, R. Mahamdi, N. Touafek, M. Pasquinelli
Among the causes of the degradation of the performance of kesterite-based solar cells is the wrong choice of the n-type buffer layer which has direct repercussions on the unfavorable band alignment, the conduction band offset (CBO) at the interface of the absorber/buffer junction which is one of the major causes of lower VOC. In this work, the effect of CBO at the interface of the junction (CZTS/Cd(1-x)ZnxS) as a function of the x composition of Zn with respect to (Zn+Cd) is studied using the SCAPS-1D simulator package. The obtained results show that the performance of the solar cells reaches a maximum values (Jsc = 13.9 mA/cm2, Voc = 0.757 V, FF = 65.6%, ɳ = 6.9%) for an optimal value of CBO = -0.2 eV and Zn proportion of the buffer x = 0.4 (Cd0.6Zn0.4S). The CZTS solar cells parameters are affected by the thickness and the concentration of acceptor carriers. The best performances are obtained for CZTS absorber layer, thichness (d = 2.5 µm) and (ND = 1016 cm-3). The obtained results of optimizing the electron work function of the back metal contact exhibited an optimum value at 5.7 eV with power conversion efficiency of 13.1%, Voc of 0.961 mV, FF of 67.3% and Jsc of 20.2 mA/cm2.
{"title":"Conduction Band Offset Effect on the Cu2ZnSnS4 Solar Cells Performance","authors":"A. Latrous, R. Mahamdi, N. Touafek, M. Pasquinelli","doi":"10.18280/acsm.450601","DOIUrl":"https://doi.org/10.18280/acsm.450601","url":null,"abstract":"Among the causes of the degradation of the performance of kesterite-based solar cells is the wrong choice of the n-type buffer layer which has direct repercussions on the unfavorable band alignment, the conduction band offset (CBO) at the interface of the absorber/buffer junction which is one of the major causes of lower VOC. In this work, the effect of CBO at the interface of the junction (CZTS/Cd(1-x)ZnxS) as a function of the x composition of Zn with respect to (Zn+Cd) is studied using the SCAPS-1D simulator package. The obtained results show that the performance of the solar cells reaches a maximum values (Jsc = 13.9 mA/cm2, Voc = 0.757 V, FF = 65.6%, ɳ = 6.9%) for an optimal value of CBO = -0.2 eV and Zn proportion of the buffer x = 0.4 (Cd0.6Zn0.4S). The CZTS solar cells parameters are affected by the thickness and the concentration of acceptor carriers. The best performances are obtained for CZTS absorber layer, thichness (d = 2.5 µm) and (ND = 1016 cm-3). The obtained results of optimizing the electron work function of the back metal contact exhibited an optimum value at 5.7 eV with power conversion efficiency of 13.1%, Voc of 0.961 mV, FF of 67.3% and Jsc of 20.2 mA/cm2.","PeriodicalId":7877,"journal":{"name":"Annales de Chimie - Science des Matériaux","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73648498","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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