Pub Date : 2023-01-01DOI: 10.3934/matersci.2023046
Salla Kälkäjä, Lenka Breugelmans, Johanna Kärkkäinen, Katja Lappalainen
In this study, orange peel waste was successfully sulfonated with SO3-pyridine complex in 1-allyl-3-methylimidazolium chloride ionic liquid in various reaction conditions. 1H NMR was used to verify the occurrence of the reaction and to select the most promising material for the adsorption experiments. The degree of substitution of the sulfonated orange peel waste used for cobalt and copper removal was found to be 0.82. It was prepared with the reaction temperature and time of 70 ℃ and 60 min respectively and with the SO3-pyridine complex to-peel waste ratio of 5:1. The selected material combined with ultrafiltration removed 98% of copper and 91% of cobalt from single metal solutions and 93% of copper and 83% of cobalt from binary metal solution at pH 5 with adsorbent dosage of 12.5 mg/100 mL and initial metal concentration of 8 mg/L. Preliminary experiments were also performed with apple pomace which was sulfonated in the conditions found best for the orange peel waste. The prepared sulfonated apple pomace proved to be almost as effective in cobalt and copper removal as sulfonated orange peel waste, removing 82% of copper and 77% of cobalt from binary metal solution with 12.5 mg/100 mL dosage at pH 5 and an initial metal concentration of 8 mg/L.
{"title":"Removal of cobalt and copper from aqueous solutions with sulfonated fruit waste","authors":"Salla Kälkäjä, Lenka Breugelmans, Johanna Kärkkäinen, Katja Lappalainen","doi":"10.3934/matersci.2023046","DOIUrl":"https://doi.org/10.3934/matersci.2023046","url":null,"abstract":"<abstract> <p>In this study, orange peel waste was successfully sulfonated with SO<sub>3</sub>-pyridine complex in 1-allyl-3-methylimidazolium chloride ionic liquid in various reaction conditions. <sup>1</sup>H NMR was used to verify the occurrence of the reaction and to select the most promising material for the adsorption experiments. The degree of substitution of the sulfonated orange peel waste used for cobalt and copper removal was found to be 0.82. It was prepared with the reaction temperature and time of 70 ℃ and 60 min respectively and with the SO<sub>3</sub>-pyridine complex to-peel waste ratio of 5:1. The selected material combined with ultrafiltration removed 98% of copper and 91% of cobalt from single metal solutions and 93% of copper and 83% of cobalt from binary metal solution at pH 5 with adsorbent dosage of 12.5 mg/100 mL and initial metal concentration of 8 mg/L. Preliminary experiments were also performed with apple pomace which was sulfonated in the conditions found best for the orange peel waste. The prepared sulfonated apple pomace proved to be almost as effective in cobalt and copper removal as sulfonated orange peel waste, removing 82% of copper and 77% of cobalt from binary metal solution with 12.5 mg/100 mL dosage at pH 5 and an initial metal concentration of 8 mg/L.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135596081","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}
To protect materials from abrasion-corrosion, various thermal spraying methods can be used to apply coatings, such as gas-flame powder spraying, plasma spraying, high velocity oxygen-fuel spraying and detonation cannon. Thermal spraying is one of the most effective methods of protecting the material from wear and corrosion, thereby increasing the service life of the material used. We present the surface modification of coatings based on Ni-Cr-Al by a pulsed plasma treatment using a plasma generator. The coatings were obtained by detonation spraying followed by pulsed plasma treatment. The changes to the structural properties of the coatings under the influence of plasma flow were studied using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The mechanical and tribological properties were analyzed by surface roughness characterization, microhardness testing and tribological tests for a comprehensive analysis of changes in the characteristics of the Ni-Cr-Al coatings following pulsed plasma treatment. It was found that modification of the coating by pulsed plasma treatment causes an increase in the microhardness of the surface layer, as well as a reduction in the surface roughness and friction coefficient. According to the results of X-ray phase analysis, these improvements in the mechanical and tribomechanical properties of the obtained surfaces is associated with an increase in the content of CrNi3, NiAl and NiCr phases in the coatings.
{"title":"Surface modification of coatings based on Ni-Cr-Al by pulsed plasma treatment","authors":"Didar Yeskermessov, Bauyrzhan Rakhadilov, Laila Zhurerova, Akbota Apsezhanova, Zarina Aringozhina, Matthew Booth, Yerkezhan Tabiyeva","doi":"10.3934/matersci.2023042","DOIUrl":"https://doi.org/10.3934/matersci.2023042","url":null,"abstract":"<abstract> <p>To protect materials from abrasion-corrosion, various thermal spraying methods can be used to apply coatings, such as gas-flame powder spraying, plasma spraying, high velocity oxygen-fuel spraying and detonation cannon. Thermal spraying is one of the most effective methods of protecting the material from wear and corrosion, thereby increasing the service life of the material used. We present the surface modification of coatings based on Ni-Cr-Al by a pulsed plasma treatment using a plasma generator. The coatings were obtained by detonation spraying followed by pulsed plasma treatment. The changes to the structural properties of the coatings under the influence of plasma flow were studied using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The mechanical and tribological properties were analyzed by surface roughness characterization, microhardness testing and tribological tests for a comprehensive analysis of changes in the characteristics of the Ni-Cr-Al coatings following pulsed plasma treatment. It was found that modification of the coating by pulsed plasma treatment causes an increase in the microhardness of the surface layer, as well as a reduction in the surface roughness and friction coefficient. According to the results of X-ray phase analysis, these improvements in the mechanical and tribomechanical properties of the obtained surfaces is associated with an increase in the content of CrNi<sub>3</sub>, NiAl and NiCr phases in the coatings.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023047
Falah Mustafa Al-Saraireh
<abstract> <p>This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on
{"title":"Cold-curing mixtures based on biopolymer lignin complex for casting production in single and small-series conditions","authors":"Falah Mustafa Al-Saraireh","doi":"10.3934/matersci.2023047","DOIUrl":"https://doi.org/10.3934/matersci.2023047","url":null,"abstract":"<abstract> <p>This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135839453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023016
Connor Castro, Zachary R. Brown, E. Brewer
Injectable polymers offer great benefits compared to other types of implants; however, they tend to suffer from increased mechanical wear and may need a replacement implant to restore these mechanical properties. The purpose of this experiment is to investigate an injectable hydrogel's self-healing ability to augment itself to a previously molded implant. This was accomplished by performing a tensile strength test to examine potential diminishing mechanical properties with increasing time, as well as dye penetration tests to examine the formation of interfacial bonds between healed areas of hydrogels. There were several time points in between injections that were explored, from 0 min between injections all the way up to 48 h in between injections. The tests showed no statistical differences of the increased injection times compared to the single injection for the tensile test. However, our results showed an increase of mechanical breaks at self-healed joints, as well as a linear regression test showed a decrease in dye diffusion rate as time between injections increase. These results show that the hydrogel has strong self-healing abilities, and as time between injections increase, they mechanical properties will slowly decrease. Based on this, the tests can be applied to other injectable implants and a noninvasive solution to a worn-down implant, as well as show scientific backing to a possibly unique and beneficial self-healing property.
{"title":"Self-healing properties of augmented injectable hydrogels over time","authors":"Connor Castro, Zachary R. Brown, E. Brewer","doi":"10.3934/matersci.2023016","DOIUrl":"https://doi.org/10.3934/matersci.2023016","url":null,"abstract":"Injectable polymers offer great benefits compared to other types of implants; however, they tend to suffer from increased mechanical wear and may need a replacement implant to restore these mechanical properties. The purpose of this experiment is to investigate an injectable hydrogel's self-healing ability to augment itself to a previously molded implant. This was accomplished by performing a tensile strength test to examine potential diminishing mechanical properties with increasing time, as well as dye penetration tests to examine the formation of interfacial bonds between healed areas of hydrogels. There were several time points in between injections that were explored, from 0 min between injections all the way up to 48 h in between injections. The tests showed no statistical differences of the increased injection times compared to the single injection for the tensile test. However, our results showed an increase of mechanical breaks at self-healed joints, as well as a linear regression test showed a decrease in dye diffusion rate as time between injections increase. These results show that the hydrogel has strong self-healing abilities, and as time between injections increase, they mechanical properties will slowly decrease. Based on this, the tests can be applied to other injectable implants and a noninvasive solution to a worn-down implant, as well as show scientific backing to a possibly unique and beneficial self-healing property.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023017
Weerayut Jina, S. Nagasawa, Teruyuki Yamamoto, Takaomi Nagumo
This study reveals the crease deviation behavior through the developed forming simulation. A combination resistance model was expanded and applied to simulate the 180° folding process of a creased paperboard, using the shear-yield detaching resistance and the out-of-plane fluffing resistance which were based on the isotropic elastro-plastic model. When varying the misalignment of the creasing rule against the groove, the eccentricity of the crease bulging of a white-coated paperboard was compared through the experiment and simulation of the 180° folding process. Comparing the experimental deformation and the simulation, it was explained that the deviation of e contributed to making the crease deviation cd. At the folding test, the 180° folding was compared with the experiment and simulation. The rolling pass of the folded zone was considered to intensify the deviation state. The 180° folding simulation revealed that the crease deviation of cd ≈ 2e was assessed as an ideal condition when using the rolling pass and non-rolling pass. In the case of some shallow indentation in the experiment, 2e < cd < 4e was observed. The inside folded corners were quite different between the simulation and experiment, especially for a certain shallow indentation model. In the simulation, the local crushing was not performed under the assumption of any isotropic properties. In the simulation, the deviation of the creased position at the 180° folding was sufficiently predictable, when compared with experimental behavior.
本研究通过发达的成形模拟揭示了折痕偏差行为。利用基于各向同性弹塑性模型的剪切屈服分离阻力和面外起绒阻力,扩展并应用组合阻力模型对折痕纸板180°折叠过程进行了模拟。通过180°折痕过程的实验和仿真,比较了在改变折痕线与凹槽的对中偏差时,白布纸板折痕胀形的偏心率。对比实验变形和仿真,解释了e的偏差对折痕偏差cd的产生有贡献。在折叠试验中,将180°折叠与实验和仿真进行了比较。考虑了褶皱区的轧制孔道加剧了偏差状态。180°折叠仿真结果表明,采用轧制孔道和非轧制孔道时,折痕偏差cd≈2e为理想状态。实验中出现一些浅压痕时,2e < cd < 4e。内部折叠角的模拟结果与实验结果存在较大差异,特别是对于某一浅压痕模型。在模拟中,在假定各向同性的情况下,不进行局部破碎。在模拟中,与实验行为相比,在180°折叠时折痕位置的偏差是充分可预测的。
{"title":"Analysis of the folding behavior of a paperboard subjected to indentation of a deviated creasing rule using the finite element method","authors":"Weerayut Jina, S. Nagasawa, Teruyuki Yamamoto, Takaomi Nagumo","doi":"10.3934/matersci.2023017","DOIUrl":"https://doi.org/10.3934/matersci.2023017","url":null,"abstract":"<abstract> <p>This study reveals the crease deviation behavior through the developed forming simulation. A combination resistance model was expanded and applied to simulate the 180° folding process of a creased paperboard, using the shear-yield detaching resistance and the out-of-plane fluffing resistance which were based on the isotropic elastro-plastic model. When varying the misalignment of the creasing rule against the groove, the eccentricity of the crease bulging of a white-coated paperboard was compared through the experiment and simulation of the 180° folding process. Comparing the experimental deformation and the simulation, it was explained that the deviation of <italic>e</italic> contributed to making the crease deviation <italic>c</italic><sub>d</sub>. At the folding test, the 180° folding was compared with the experiment and simulation. The rolling pass of the folded zone was considered to intensify the deviation state. The 180° folding simulation revealed that the crease deviation of <italic>c</italic><sub>d</sub> ≈ 2<italic>e</italic> was assessed as an ideal condition when using the rolling pass and non-rolling pass. In the case of some shallow indentation in the experiment, 2<italic>e</italic> < <italic>c</italic><sub><italic>d</italic></sub> < 4<italic>e</italic> was observed. The inside folded corners were quite different between the simulation and experiment, especially for a certain shallow indentation model. In the simulation, the local crushing was not performed under the assumption of any isotropic properties. In the simulation, the deviation of the creased position at the 180° folding was sufficiently predictable, when compared with experimental behavior.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023018
Sree Sourav Das, Zach Fox, Md Dalim Mia, B. C. Samuels, R. Saha, R. Droopad
Ferroelectricity is demonstrated for the first time in Si(100)/SiO2/TiN/HfO2-ZrO2/TiN stack using pulsed laser deposition (PLD) and the effects of temperatures, partial oxygen pressures, and thickness for the stabilization of the ferroelectric phase were mapped. Thin films deposited at a higher temperature and a higher oxygen partial pressure have a higher thickness, demonstrating a better ferroelectric response with ~12 μC/cm2 remnant polarization, a leakage current of 10−7 A (at 8 V) and endurance > 1011 cycles indicative of an orthorhombic crystal phase. In contrast, thin films deposited at lower temperatures and pressures does not exhibit ferroelectric behavior. These films can be attributed to having a dominant monoclinic phase, having lower grain size and increased leakage current. Finally, the effects of ZrO2 as top and bottom layer were also investigated which showed that ZrO2 as the top layer provided better mechanical confinement for stabilizing the orthorhombic phase instead of as the bottom layer.
利用脉冲激光沉积(PLD)技术首次在Si(100)/SiO2/TiN/HfO2-ZrO2/TiN叠层中证明了铁电性,并绘制了温度、氧分压和厚度对铁电相稳定的影响。在较高的温度和氧分压下沉积的薄膜具有较高的厚度,具有较好的铁电响应,残余极化为~12 μC/cm2,漏电流为10−7 a (8 V),续航时间为> 1011次,表明其为正交晶相。相反,在较低温度和压力下沉积的薄膜不表现出铁电行为。这些薄膜的主要特点是单斜相,晶粒尺寸较小,漏电流增大。最后,对ZrO2作为顶层和底层的影响进行了研究,结果表明ZrO2作为顶层比作为底层对稳定正交相提供了更好的机械约束。
{"title":"Demonstration of ferroelectricity in PLD grown HfO2-ZrO2 nanolaminates","authors":"Sree Sourav Das, Zach Fox, Md Dalim Mia, B. C. Samuels, R. Saha, R. Droopad","doi":"10.3934/matersci.2023018","DOIUrl":"https://doi.org/10.3934/matersci.2023018","url":null,"abstract":"<abstract> <p>Ferroelectricity is demonstrated for the first time in Si(100)/SiO<sub>2</sub>/TiN/HfO<sub>2</sub>-ZrO<sub>2</sub>/TiN stack using pulsed laser deposition (PLD) and the effects of temperatures, partial oxygen pressures, and thickness for the stabilization of the ferroelectric phase were mapped. Thin films deposited at a higher temperature and a higher oxygen partial pressure have a higher thickness, demonstrating a better ferroelectric response with ~12 μC/cm<sup>2</sup> remnant polarization, a leakage current of 10<sup>−7</sup> A (at 8 V) and endurance > 10<sup>11</sup> cycles indicative of an orthorhombic crystal phase. In contrast, thin films deposited at lower temperatures and pressures does not exhibit ferroelectric behavior. These films can be attributed to having a dominant monoclinic phase, having lower grain size and increased leakage current. Finally, the effects of ZrO<sub>2</sub> as top and bottom layer were also investigated which showed that ZrO<sub>2</sub> as the top layer provided better mechanical confinement for stabilizing the orthorhombic phase instead of as the bottom layer.</p> </abstract>","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023006
A. S. Karzad, M. Leblouba, Z. Al-Sadoon, M. Maalej, S. Altoubat
Industrial applications of fibre-reinforced concrete (FRC) in structures require extensive experimental and analytical investigations of the FRC material properties. For design purposes and applications involving the flexural loading of the member, it is essential to have a predictive model for the flexural strength of the FRC material. In the present paper, a fracture mechanics approach based on Bridged Crack Model (BCM) is used to predict the flexural strength of steel fibre-reinforced concrete (SFRC) beams. The model assumes a quadratic tension-softening relationship (σ-δ) governing the bridging action of the steel fibres and a linear profile of the propagating crack. The proposed tension-softening relationship is considered valid for a wide range of fibre-reinforced concrete materials based on the knowledge of either the material micromechanical parameters (such as fibre volume fraction, fibre/matrix bond strength, fibre length, and fibre tensile strength) or an actual experimentally-measured σ-δ relationship. The flexural strength model thus obtained allows the prediction of the flexural strength of SFRC and study the variation of the latter as a function of the micromechanical parameters. An experimental program involving the flexural testing of 13 SFRC prism series was carried out to verify the prediction of the proposed model. The SFRC mixes incorporated two types of steel fibres (straight-end and hooked-end), four different concrete compressive strengths (40, 50, 60, and 70 MPa), three different fibre volume fractions (1, 1.5, and 2%), and three specimen depths (100, 150, and 200 mm). The experimental results were compared to the predictions of the proposed flexural strength model, and a reasonable agreement between the two has been observed. The model provided a useful physical explanation for the observed variation of flexural strength as a function of the test variables investigated in this study.
{"title":"Modeling the flexural strength of steel fibre reinforced concrete","authors":"A. S. Karzad, M. Leblouba, Z. Al-Sadoon, M. Maalej, S. Altoubat","doi":"10.3934/matersci.2023006","DOIUrl":"https://doi.org/10.3934/matersci.2023006","url":null,"abstract":"Industrial applications of fibre-reinforced concrete (FRC) in structures require extensive experimental and analytical investigations of the FRC material properties. For design purposes and applications involving the flexural loading of the member, it is essential to have a predictive model for the flexural strength of the FRC material. In the present paper, a fracture mechanics approach based on Bridged Crack Model (BCM) is used to predict the flexural strength of steel fibre-reinforced concrete (SFRC) beams. The model assumes a quadratic tension-softening relationship (σ-δ) governing the bridging action of the steel fibres and a linear profile of the propagating crack. The proposed tension-softening relationship is considered valid for a wide range of fibre-reinforced concrete materials based on the knowledge of either the material micromechanical parameters (such as fibre volume fraction, fibre/matrix bond strength, fibre length, and fibre tensile strength) or an actual experimentally-measured σ-δ relationship. The flexural strength model thus obtained allows the prediction of the flexural strength of SFRC and study the variation of the latter as a function of the micromechanical parameters. An experimental program involving the flexural testing of 13 SFRC prism series was carried out to verify the prediction of the proposed model. The SFRC mixes incorporated two types of steel fibres (straight-end and hooked-end), four different concrete compressive strengths (40, 50, 60, and 70 MPa), three different fibre volume fractions (1, 1.5, and 2%), and three specimen depths (100, 150, and 200 mm). The experimental results were compared to the predictions of the proposed flexural strength model, and a reasonable agreement between the two has been observed. The model provided a useful physical explanation for the observed variation of flexural strength as a function of the test variables investigated in this study.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023009
Wisatre Kongcharoensuntorn, Pornpen Atorngitjawat
The effect of chlorotrifluoroethylene (CTFE) on dynamic relaxations of poly(vinylidenefluoride-co-chlorotrifluoroethylene) films (P(VDF-CTFE)) containing 0, 10, 15 and 20% of CTFE was investigated via broadband dielectric spectroscopy (DRS) and dynamic mechanical analysis (DMA). The interpretation was accompanied by the crystal structure obtained from Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering and differential scanning calorimetry. Increment of CTFE contents caused reducing the degree of crystallinity but did not impact the long period, lamellar thickness, and amorphous layer thickness. Four dynamic processes were clearly observed in DRS spectra for the neat poly(vinylidene fluoride) and P(VDF-CTFE) which were attributed to the local motion of amorphous chains (β), the segmental relaxation of amorphous chains (α1), the local conformational rearrangement of the TGTGʹ conformation (α2) and the process associated with Maxwell–Wagner–Sillars interfacial polarization (αMWS). The extra relaxation was observed for P(VDF-CTFE), which was more likely associated to the molecular motion of CTFE chain segments (αc), correspondent with DMA results. These PVDF and P(VDF-CTFE) conducted as self-antibacterial materials.
{"title":"Influence of chlorotrifluoroethylene on crystal structure and polymer dynamics of poly(vinylidenefluoride-co-chlorotrifluoroethylene) antibacterial copolymers","authors":"Wisatre Kongcharoensuntorn, Pornpen Atorngitjawat","doi":"10.3934/matersci.2023009","DOIUrl":"https://doi.org/10.3934/matersci.2023009","url":null,"abstract":"The effect of chlorotrifluoroethylene (CTFE) on dynamic relaxations of poly(vinylidenefluoride-co-chlorotrifluoroethylene) films (P(VDF-CTFE)) containing 0, 10, 15 and 20% of CTFE was investigated via broadband dielectric spectroscopy (DRS) and dynamic mechanical analysis (DMA). The interpretation was accompanied by the crystal structure obtained from Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, small-angle X-ray scattering and differential scanning calorimetry. Increment of CTFE contents caused reducing the degree of crystallinity but did not impact the long period, lamellar thickness, and amorphous layer thickness. Four dynamic processes were clearly observed in DRS spectra for the neat poly(vinylidene fluoride) and P(VDF-CTFE) which were attributed to the local motion of amorphous chains (β), the segmental relaxation of amorphous chains (α1), the local conformational rearrangement of the TGTGʹ conformation (α2) and the process associated with Maxwell–Wagner–Sillars interfacial polarization (αMWS). The extra relaxation was observed for P(VDF-CTFE), which was more likely associated to the molecular motion of CTFE chain segments (αc), correspondent with DMA results. These PVDF and P(VDF-CTFE) conducted as self-antibacterial materials.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70089959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023024
J. Mahy, C. Carcel, M. W. Chi Man
An Evonik P25 TiO2 material is modified using a porphyrin containing Si-(OR)3 extremities to extend its absorption spectrum in the visible range. Two different loadings of porphyrin are grafted at the surface of P25. The results show that the crystallinity and the texture of the P25 are not modified with the porphyrin grafting and the presence of the latter is confirmed by Fourier-transform infrared spectroscopy (FTIR) measurements. All three samples are composed of anatase/rutile titania nanoparticles around 20 nm in size with a spherical shape. The absorption spectra of the porphyrin modified samples show visible absorption alongside the characteristic Soret and Q bands of porphyrin, despite slightly shifted peak values. The 29Si solid state nuclear magnetic resonance (NMR) spectra show that the porphyrin is linked with Ti–O–C and Ti–O–Si bonds with the Evonik P25, allowing for a direct electron transfer between the two materials. Finally, the photoactivity of the materials is assessed on the degradation of a model pollutant—p-nitrophenol (PNP)—in water. The degradation is substantially enhanced when the porphyrin is grafted at its surface, whereas a very low activity is evidenced for P25. Indeed, with the best sample, the activity increases from 9% to 38% under visible light illumination. This improvement is due to the activation of the porphyrin under visible light that produces electrons, which are then transferred to the TiO2 to generate radicals able to degrade organic pollutants. The observed degradation is confirmed to be a mineralization of the PNP. Recycling experiments show a constant PNP degradation after 5 cycles of photocatalysis of 24 h each.
{"title":"Evonik P25 photoactivation in the visible range by surface grafting of modified porphyrins for p-nitrophenol elimination in water","authors":"J. Mahy, C. Carcel, M. W. Chi Man","doi":"10.3934/matersci.2023024","DOIUrl":"https://doi.org/10.3934/matersci.2023024","url":null,"abstract":"An Evonik P25 TiO2 material is modified using a porphyrin containing Si-(OR)3 extremities to extend its absorption spectrum in the visible range. Two different loadings of porphyrin are grafted at the surface of P25. The results show that the crystallinity and the texture of the P25 are not modified with the porphyrin grafting and the presence of the latter is confirmed by Fourier-transform infrared spectroscopy (FTIR) measurements. All three samples are composed of anatase/rutile titania nanoparticles around 20 nm in size with a spherical shape. The absorption spectra of the porphyrin modified samples show visible absorption alongside the characteristic Soret and Q bands of porphyrin, despite slightly shifted peak values. The 29Si solid state nuclear magnetic resonance (NMR) spectra show that the porphyrin is linked with Ti–O–C and Ti–O–Si bonds with the Evonik P25, allowing for a direct electron transfer between the two materials. Finally, the photoactivity of the materials is assessed on the degradation of a model pollutant—p-nitrophenol (PNP)—in water. The degradation is substantially enhanced when the porphyrin is grafted at its surface, whereas a very low activity is evidenced for P25. Indeed, with the best sample, the activity increases from 9% to 38% under visible light illumination. This improvement is due to the activation of the porphyrin under visible light that produces electrons, which are then transferred to the TiO2 to generate radicals able to degrade organic pollutants. The observed degradation is confirmed to be a mineralization of the PNP. Recycling experiments show a constant PNP degradation after 5 cycles of photocatalysis of 24 h each.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70090312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.3934/matersci.2023034
K. A. Lazopoulos, A. Lazopoulos
Since the global stability criteria for Λ-fractional mechanics have been established, the Λ-fractional beam bending problem is discussed within that context. The co-existence of the phase phenomenon is revealed, allowing for elastic curves with non-smooth curvatures. The variational bending problem in the Λ-fractional space is considered. Global minimization of the total energy function of beam bending is necessarily applied. The variational Euler-Lagrange equation yields an equilibrium equation of the elastic curve, with the simultaneous possible corners being expressed by Weierstrass-Erdmann corner conditions.
{"title":"Beam bending and Λ-fractional analysis","authors":"K. A. Lazopoulos, A. Lazopoulos","doi":"10.3934/matersci.2023034","DOIUrl":"https://doi.org/10.3934/matersci.2023034","url":null,"abstract":"Since the global stability criteria for Λ-fractional mechanics have been established, the Λ-fractional beam bending problem is discussed within that context. The co-existence of the phase phenomenon is revealed, allowing for elastic curves with non-smooth curvatures. The variational bending problem in the Λ-fractional space is considered. Global minimization of the total energy function of beam bending is necessarily applied. The variational Euler-Lagrange equation yields an equilibrium equation of the elastic curve, with the simultaneous possible corners being expressed by Weierstrass-Erdmann corner conditions.","PeriodicalId":7670,"journal":{"name":"AIMS Materials Science","volume":"1 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70090512","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}