V. Savov, P. Antov, Christian Panchev, M. A. R. Lubis, H. R. Taghiyari, S. Lee, Ľ. Krišťák, Martina Todorova
Recycling medium-density fiberboards (MDF) presents notable technological challenges, primarily due to the deteriorated properties of the recycled wood fibers obtained from MDF waste. On the other hand, the enhanced valorization of recycled wood in the manufacturing of wood composites represents a viable approach for implementing the principles of a circular bio-economy in the wood-based panel industry and lowering its carbon footprint. This research aimed to investigate and evaluate the impact of the hydrothermal hydrolysis regime on the physical and mechanical properties of recycled MDF panels (rMDF). The hydrolysis temperature was varied from 121 °C (saturated steam pressure 0.2 MPa) to 134 °C (saturated steam pressure 0.3 MPa), and three hydrolysis durations, i.e., 30, 45, and 60 min, were applied. A control MDF panel, manufactured in laboratory conditions from industrial pulp, was used to perform the comparative analyses. It was observed that the degradation of the rMDF panels occurred when the hydrolysis temperature was increased from 121 °C to 134 °C. The research confirmed the deteriorated physical and mechanical properties of rMDF compared to the panels manufactured from natural wood fibers. Markedly, no significant differences were detected between the density profiles of the rMDF panels and the control boards fabricated from industrial pulp. As a result of the study, it was found that the hydrolysis temperature has a more significant effect than the processing time. It was also established that, in the preliminary preparation of the MDF panels into samples with dimensions similar to those of pulp chips, the optimal hydrolysis regime is at a temperature of 121° C (saturated steam pressure 0.2 MPa) and a time of 30 min.
{"title":"The Impact of Hydrolysis Regime on the Physical and Mechanical Characteristics of Medium-Density Fiberboards Manufactured from Recycled Wood Fibers","authors":"V. Savov, P. Antov, Christian Panchev, M. A. R. Lubis, H. R. Taghiyari, S. Lee, Ľ. Krišťák, Martina Todorova","doi":"10.3390/fib11120103","DOIUrl":"https://doi.org/10.3390/fib11120103","url":null,"abstract":"Recycling medium-density fiberboards (MDF) presents notable technological challenges, primarily due to the deteriorated properties of the recycled wood fibers obtained from MDF waste. On the other hand, the enhanced valorization of recycled wood in the manufacturing of wood composites represents a viable approach for implementing the principles of a circular bio-economy in the wood-based panel industry and lowering its carbon footprint. This research aimed to investigate and evaluate the impact of the hydrothermal hydrolysis regime on the physical and mechanical properties of recycled MDF panels (rMDF). The hydrolysis temperature was varied from 121 °C (saturated steam pressure 0.2 MPa) to 134 °C (saturated steam pressure 0.3 MPa), and three hydrolysis durations, i.e., 30, 45, and 60 min, were applied. A control MDF panel, manufactured in laboratory conditions from industrial pulp, was used to perform the comparative analyses. It was observed that the degradation of the rMDF panels occurred when the hydrolysis temperature was increased from 121 °C to 134 °C. The research confirmed the deteriorated physical and mechanical properties of rMDF compared to the panels manufactured from natural wood fibers. Markedly, no significant differences were detected between the density profiles of the rMDF panels and the control boards fabricated from industrial pulp. As a result of the study, it was found that the hydrolysis temperature has a more significant effect than the processing time. It was also established that, in the preliminary preparation of the MDF panels into samples with dimensions similar to those of pulp chips, the optimal hydrolysis regime is at a temperature of 121° C (saturated steam pressure 0.2 MPa) and a time of 30 min.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":" 10","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138618226","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}
Ofelia Maldonado-Santiago, J. Robles-Ocampo, Eduardo Gálvez, P. Y. Sevilla-Camacho, Sergio de la Cruz, J. Rodríguez-Reséndíz, Edwin Hernández
Wind turbine blades in excessive wind conditions present extreme deflection problems. For this reason, an analysis of the structural response of composite reinforced box beams is developed. For this purpose, reinforced box beams were fabricated to improve the bending strength in the flapwise direction of the wind turbine blades. The box beams were analyzed with three-dimensional models using the Finite Element Method (FEM) and validated with bending tests at four-points and two-points. The box beam meets the characteristics of lightness and mechanical strength. Experimental four-point bending results showed that reinforced cross-sections decrease displacements by 30.09% and increase their stiffness to 43.41% for a box beam without structural reinforcement. In addition, the two-point bending results showed a difference of 18.98% between the displacements of the beams with structural reinforcements. In the FEM analysis, a maximum error of 11.24% was obtained when correlating the maximum displacement value with the experimental results of the beams.
{"title":"Bending Behavior Analysis of Box Beams with the Reinforcement of Composite Materials for Wind Turbine Blades","authors":"Ofelia Maldonado-Santiago, J. Robles-Ocampo, Eduardo Gálvez, P. Y. Sevilla-Camacho, Sergio de la Cruz, J. Rodríguez-Reséndíz, Edwin Hernández","doi":"10.3390/fib11120099","DOIUrl":"https://doi.org/10.3390/fib11120099","url":null,"abstract":"Wind turbine blades in excessive wind conditions present extreme deflection problems. For this reason, an analysis of the structural response of composite reinforced box beams is developed. For this purpose, reinforced box beams were fabricated to improve the bending strength in the flapwise direction of the wind turbine blades. The box beams were analyzed with three-dimensional models using the Finite Element Method (FEM) and validated with bending tests at four-points and two-points. The box beam meets the characteristics of lightness and mechanical strength. Experimental four-point bending results showed that reinforced cross-sections decrease displacements by 30.09% and increase their stiffness to 43.41% for a box beam without structural reinforcement. In addition, the two-point bending results showed a difference of 18.98% between the displacements of the beams with structural reinforcements. In the FEM analysis, a maximum error of 11.24% was obtained when correlating the maximum displacement value with the experimental results of the beams.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"64 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139250181","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}
Daria Śmigiel-Kamińska, J. Wąs-Gubała, J. Kumirska
The purpose of this study was to detect changes in the structure and chemical composition of undyed and dyed cotton fabrics under the influence of six popular agents for disinfection, sterilization, and DNA degradation with different chemical compositions. The original and exposed fabrics and their constituent fibers were subjected to comparative analysis using various optical microscopy methods, infrared spectroscopy, and UV–Vis microspectrophotometry in order to differentiate the exanimated material due to the agents applied. Differences in color, from a slight change to complete discoloration, and in the structure of the tested fabrics, which became more rigid, brittle, or, for example, compact, were noticed. With the use of ATR FTIR, it was possible to identify the presence in the exposed fabrics of residues of these agents that contained quaternary ammonium salts. Bright-field microscopy made it possible to show, above all, changes or lack thereof in the fluorescence properties of single exposed fibers in relation to control ones. With the use of UV–Vis microspectrophotometry, changes in colored fibers following the action of a specific agent on the examined fabrics were monitored. A case study was presented as an application aspect of the research, in which the use of concrete disinfectants was recognized based on changes observed in cotton clothing.
本研究的目的是检测未染色和染色棉织物在六种不同化学成分的常用消毒、杀菌和 DNA 降解剂影响下的结构和化学成分变化。使用各种光学显微镜方法、红外光谱法和紫外可见显微分光光度法对原始织物和染色织物及其组成纤维进行了比较分析，以区分因所使用的药剂而发生变化的材料。我们注意到，被测织物的颜色（从轻微变化到完全褪色）和结构（变得更硬、更脆或更紧密）都有所不同。利用 ATR 傅立叶变换红外技术，可以确定在暴露的织物中存在这些含有季铵盐的药剂残留物。通过明视显微镜，首先可以看到单根暴露纤维的荧光特性与对照纤维相比有无变化。利用紫外可见显微分光光度法，可以监测特定药剂作用于受检织物后有色纤维的变化。作为研究的应用方面，介绍了一个案例研究，其中根据在棉质衣物上观察到的变化，确认了混凝土消毒剂的使用。
{"title":"Comparative Studies of Changes in Cotton Fabrics and Fibers under the Influence of Disinfection, Sterilization, and DNA Degradation Agents","authors":"Daria Śmigiel-Kamińska, J. Wąs-Gubała, J. Kumirska","doi":"10.3390/fib11120100","DOIUrl":"https://doi.org/10.3390/fib11120100","url":null,"abstract":"The purpose of this study was to detect changes in the structure and chemical composition of undyed and dyed cotton fabrics under the influence of six popular agents for disinfection, sterilization, and DNA degradation with different chemical compositions. The original and exposed fabrics and their constituent fibers were subjected to comparative analysis using various optical microscopy methods, infrared spectroscopy, and UV–Vis microspectrophotometry in order to differentiate the exanimated material due to the agents applied. Differences in color, from a slight change to complete discoloration, and in the structure of the tested fabrics, which became more rigid, brittle, or, for example, compact, were noticed. With the use of ATR FTIR, it was possible to identify the presence in the exposed fabrics of residues of these agents that contained quaternary ammonium salts. Bright-field microscopy made it possible to show, above all, changes or lack thereof in the fluorescence properties of single exposed fibers in relation to control ones. With the use of UV–Vis microspectrophotometry, changes in colored fibers following the action of a specific agent on the examined fabrics were monitored. A case study was presented as an application aspect of the research, in which the use of concrete disinfectants was recognized based on changes observed in cotton clothing.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"211 ","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139248452","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}
Mohamed R. Emara, Mohamed A. Salem, Heba A. Mohamed, Hamdy A. Shehab, Ayman El-Zohairy
This study evaluates the performance of Reinforced Concrete (RC) beams enhanced in shear using Engineered Cementitious Composites (ECCs) and Carbon Fiber-Reinforced Polymers (CFRPs). The experimental study encompasses fifteen RC beams. This set includes one control specimen and fourteen beams fortified in shear with Externally Bonded (EB) composites. Two of these specimens were enhanced with ECC layers, while the remaining were augmented with combined CFRP-ECC layers. Variables in the test included the ECC layer thickness, matrix type, number of CFRP layers, and strengthening configurations such as full wrapping, vertical strips, and inclined strips. The results indicated that the shear capacity of the fortified beams increased by 61.1% to 160.1% compared to the control specimen. The most effective structural performance was observed in the full wrapping method, which utilized a single CFRP layer combined with either 20 mm or 40 mm ECC thickness, outperforming other techniques. However, the inclined strip method demonstrated a notably higher load-bearing capacity than the full wrapping approach for beams with double CFRP layers paired with 20 mm and 40 mm ECC thicknesses. This configuration also exhibited superior ductility compared to the rest. Furthermore, the experimental shear capacities obtained were juxtaposed with theoretical values from prevailing design standards.
{"title":"Shear Strengthening of Reinforced Concrete Beams Using Engineered Cementitious Composites and Carbon Fiber-Reinforced Polymer Sheets","authors":"Mohamed R. Emara, Mohamed A. Salem, Heba A. Mohamed, Hamdy A. Shehab, Ayman El-Zohairy","doi":"10.3390/fib11110098","DOIUrl":"https://doi.org/10.3390/fib11110098","url":null,"abstract":"This study evaluates the performance of Reinforced Concrete (RC) beams enhanced in shear using Engineered Cementitious Composites (ECCs) and Carbon Fiber-Reinforced Polymers (CFRPs). The experimental study encompasses fifteen RC beams. This set includes one control specimen and fourteen beams fortified in shear with Externally Bonded (EB) composites. Two of these specimens were enhanced with ECC layers, while the remaining were augmented with combined CFRP-ECC layers. Variables in the test included the ECC layer thickness, matrix type, number of CFRP layers, and strengthening configurations such as full wrapping, vertical strips, and inclined strips. The results indicated that the shear capacity of the fortified beams increased by 61.1% to 160.1% compared to the control specimen. The most effective structural performance was observed in the full wrapping method, which utilized a single CFRP layer combined with either 20 mm or 40 mm ECC thickness, outperforming other techniques. However, the inclined strip method demonstrated a notably higher load-bearing capacity than the full wrapping approach for beams with double CFRP layers paired with 20 mm and 40 mm ECC thicknesses. This configuration also exhibited superior ductility compared to the rest. Furthermore, the experimental shear capacities obtained were juxtaposed with theoretical values from prevailing design standards.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"2 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139277069","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}
Alena Balogová, Bibiána Bizubová, Michal Kleščík, Tomáš Zatroch
In this work, an in situ study is presented of the impact of textile materials used in healthcare facilities on microbial colonization of textile surfaces. The available literature describes antimicrobial active textiles and their effectiveness in laboratory conditions. However, the quantification of the impact on the microbiome of healthcare facilities has not been investigated so far. Polypropylene yarns doped with silver phosphate glass and zinc pyrithione were prepared and used for the production of bed sheets and clothing for healthcare personnel. Subsequently, measurements of airborne particles and viable microorganisms on given textiles were conducted in a private surgery clinic for 3 weeks, comparing the counts of viable microorganisms before and after replacing staff clothing and bedding on examination and the surgical bed with said polypropylene cloth. A significant reduction in airborne particles and viable microorganisms was expected based on previous studies on the use of polypropylene textiles in operating rooms. In this study, a significant reduction in viable airborne fungi and viable microorganisms on monitored textiles was observed by multiple methods. However, the effect on airborne microorganisms seems insignificant in areas with frequent patient traffic. The textile described here represents a new additional way of protecting patients and medical personnel from healthcare-associated infections while using a modification of proven production procedures and commercially usable materials without legislative restrictions.
{"title":"Field Study of Activity of Antimicrobial Polypropylene Textiles","authors":"Alena Balogová, Bibiána Bizubová, Michal Kleščík, Tomáš Zatroch","doi":"10.3390/fib11110097","DOIUrl":"https://doi.org/10.3390/fib11110097","url":null,"abstract":"In this work, an in situ study is presented of the impact of textile materials used in healthcare facilities on microbial colonization of textile surfaces. The available literature describes antimicrobial active textiles and their effectiveness in laboratory conditions. However, the quantification of the impact on the microbiome of healthcare facilities has not been investigated so far. Polypropylene yarns doped with silver phosphate glass and zinc pyrithione were prepared and used for the production of bed sheets and clothing for healthcare personnel. Subsequently, measurements of airborne particles and viable microorganisms on given textiles were conducted in a private surgery clinic for 3 weeks, comparing the counts of viable microorganisms before and after replacing staff clothing and bedding on examination and the surgical bed with said polypropylene cloth. A significant reduction in airborne particles and viable microorganisms was expected based on previous studies on the use of polypropylene textiles in operating rooms. In this study, a significant reduction in viable airborne fungi and viable microorganisms on monitored textiles was observed by multiple methods. However, the effect on airborne microorganisms seems insignificant in areas with frequent patient traffic. The textile described here represents a new additional way of protecting patients and medical personnel from healthcare-associated infections while using a modification of proven production procedures and commercially usable materials without legislative restrictions.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"101 13","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135137560","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}
Dunia Blaser, Pascal Hänzi, Sönke Pilz, Alexander Heidt, Valerio Romano
Rare-earth-doped optical fibres are widely used in lasers and amplifiers. The incorporation of ytterbium and aluminium oxide in a high doping concentration has led to the fabrication of a multi-mode (MM) optical fibre. Within this research, the design, preparation and calculation for the production of a fibre with a targeted 45 μm core diameter are explored. By Energy Dispersive X-ray (EDX) analysis, the doping concentrations of the elements in the core have been measured as 60.4 at.% Al and 1 at.% Yb. Supporting micrographs are used for confirming the core/cladding ratio. Based on the atomic percentage concentration, the calculated refractive index of the multi-element core has an n = 1.61 and an NA = 0.678. Characterisation of the fibre, including absorption and emission cross-section analysis, was performed in order to prove the ability of the fibre to be used for amplification as well as lasing applications.
{"title":"Multimode Ytterbium–Aluminosilicate Core Optical Fibre for Amplification and Laser Applications","authors":"Dunia Blaser, Pascal Hänzi, Sönke Pilz, Alexander Heidt, Valerio Romano","doi":"10.3390/fib11110095","DOIUrl":"https://doi.org/10.3390/fib11110095","url":null,"abstract":"Rare-earth-doped optical fibres are widely used in lasers and amplifiers. The incorporation of ytterbium and aluminium oxide in a high doping concentration has led to the fabrication of a multi-mode (MM) optical fibre. Within this research, the design, preparation and calculation for the production of a fibre with a targeted 45 μm core diameter are explored. By Energy Dispersive X-ray (EDX) analysis, the doping concentrations of the elements in the core have been measured as 60.4 at.% Al and 1 at.% Yb. Supporting micrographs are used for confirming the core/cladding ratio. Based on the atomic percentage concentration, the calculated refractive index of the multi-element core has an n = 1.61 and an NA = 0.678. Characterisation of the fibre, including absorption and emission cross-section analysis, was performed in order to prove the ability of the fibre to be used for amplification as well as lasing applications.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"330 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135392735","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}
An experimental study is performed to determine the head mechanics of American football helmets equipped with novel fiber energy absorbing material (FEAM). FEAM-based padding materials have substrates of textile fabrics and foam made with nylon fibers using electro-static flocking process. Both linear and angular accelerations of the sport helmets are determined under impact loads using a custom-built linear impactor and instrumented head. The effectiveness of padding materials and vinyl nitrile (VN) foam for impact loads on six different head positions that simulate two helmeted sport athletes in real-time helmet-to-helmet strike/impact is investigated. A high-speed camera is used to record and track neck flexion angles and compare them with pad effectiveness to better understand the head kinematics of struck players at three different impact speeds (6 m/s, 8 m/s, and 10 m/s). At impact speed of 6 m/s and 8 m/s, the FEAM-based padding material of 60 denier fibers showed superior resistance for angular acceleration. Although novel pads of VN foam flocked with 60 denier fibers outperformed with lowest linear acceleration for most of the head positions at low impact speed of 6 m/s, VN foam with no fibers demonstrated excellent performance for linear acceleration at other two speeds.
{"title":"Novel Fiber-Based Padding Materials for Football Helmets","authors":"Jared J. Correia, Vijaya Chalivendra, Yong Kim","doi":"10.3390/fib11110096","DOIUrl":"https://doi.org/10.3390/fib11110096","url":null,"abstract":"An experimental study is performed to determine the head mechanics of American football helmets equipped with novel fiber energy absorbing material (FEAM). FEAM-based padding materials have substrates of textile fabrics and foam made with nylon fibers using electro-static flocking process. Both linear and angular accelerations of the sport helmets are determined under impact loads using a custom-built linear impactor and instrumented head. The effectiveness of padding materials and vinyl nitrile (VN) foam for impact loads on six different head positions that simulate two helmeted sport athletes in real-time helmet-to-helmet strike/impact is investigated. A high-speed camera is used to record and track neck flexion angles and compare them with pad effectiveness to better understand the head kinematics of struck players at three different impact speeds (6 m/s, 8 m/s, and 10 m/s). At impact speed of 6 m/s and 8 m/s, the FEAM-based padding material of 60 denier fibers showed superior resistance for angular acceleration. Although novel pads of VN foam flocked with 60 denier fibers outperformed with lowest linear acceleration for most of the head positions at low impact speed of 6 m/s, VN foam with no fibers demonstrated excellent performance for linear acceleration at other two speeds.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"331 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135392731","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}
In the era of environmental concerns, many attempts were proposed to optimize energy efficiency for buildings and consequently reduce their carbon footprint. As a sustainable approach, it is a promising solution to incorporate phase change materials (PCMs) in construction materials (i.e., ultra-high-performance concrete (UHPC)) to increase its thermal storage capacity and reduce the operation energy. However, incorporating microencapsulated phase change materials (MPCMs) into cementitious materials negatively impacts the fresh and hardened properties. UHPC’s improved mechanical strength allows for the creation of slimmer and lighter structures, which may result in less demand in concrete manufacturing and fewer emissions. Hence, the properties of UHPC incorporated with MPCMs (MPCM-UHPC) need more investigations. To fill the gap in the literature about the lack of information about MPCM-UHPC performance, this paper provides a comprehensive work to study the mechanical, thermal, and impact resistance properties of (MPCM-UHPC). Proportions of 5% and 10% of MPCMs were incorporated as a replacement of sand by volume. Proportions of 0.5%, 1.0%, and 1.5% of micro steel fiber reinforcement were used as a percentage of the mixture’s total volume. The results revealed the importance of fiber reinforcement in compensating for the negative effect of MPCMs inclusion for improving the thermal properties. Increasing the amount of MPCMs enhanced the thermal performance of the produced UHPC panels through the ability to absorb and release the energy during the phase change process.
{"title":"Performance of Fiber-Reinforced Ultra-High-Performance Concrete Incorporated with Microencapsulated Phase Change Materials","authors":"Mahmoud Rady, Ahmed M. Soliman","doi":"10.3390/fib11110094","DOIUrl":"https://doi.org/10.3390/fib11110094","url":null,"abstract":"In the era of environmental concerns, many attempts were proposed to optimize energy efficiency for buildings and consequently reduce their carbon footprint. As a sustainable approach, it is a promising solution to incorporate phase change materials (PCMs) in construction materials (i.e., ultra-high-performance concrete (UHPC)) to increase its thermal storage capacity and reduce the operation energy. However, incorporating microencapsulated phase change materials (MPCMs) into cementitious materials negatively impacts the fresh and hardened properties. UHPC’s improved mechanical strength allows for the creation of slimmer and lighter structures, which may result in less demand in concrete manufacturing and fewer emissions. Hence, the properties of UHPC incorporated with MPCMs (MPCM-UHPC) need more investigations. To fill the gap in the literature about the lack of information about MPCM-UHPC performance, this paper provides a comprehensive work to study the mechanical, thermal, and impact resistance properties of (MPCM-UHPC). Proportions of 5% and 10% of MPCMs were incorporated as a replacement of sand by volume. Proportions of 0.5%, 1.0%, and 1.5% of micro steel fiber reinforcement were used as a percentage of the mixture’s total volume. The results revealed the importance of fiber reinforcement in compensating for the negative effect of MPCMs inclusion for improving the thermal properties. Increasing the amount of MPCMs enhanced the thermal performance of the produced UHPC panels through the ability to absorb and release the energy during the phase change process.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"24 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135868527","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}
Arup Kar, Dip Saikia, Sivasubramanian Palanisamy, Carlo Santulli, Cristiano Fragassa, Sabu Thomas
This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial.
{"title":"Effect of Alkali Treatment under Ambient and Heated Conditions on the Physicochemical, Structural, Morphological, and Thermal Properties of Calamus tenuis Cane Fibers","authors":"Arup Kar, Dip Saikia, Sivasubramanian Palanisamy, Carlo Santulli, Cristiano Fragassa, Sabu Thomas","doi":"10.3390/fib11110092","DOIUrl":"https://doi.org/10.3390/fib11110092","url":null,"abstract":"This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"18 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934265","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}
Ehsan Harati Khalilabad, Alvaro Ruiz Emparanza, Francisco De Caso, Hossein Roghani, Nima Khodadadi, Antonio Nanni
Pultruded FRP composites have emerged as a promising alternative to traditional materials like concrete, steel, and timber, especially in corrosive environmental conditions. However, the unique properties of these composites necessitate careful consideration during their implementation, as they differ significantly from conventional materials. Proper testing and characterization of FRP pultruded materials is key for their efficient and safe implementation. However, the existing specifications are not unified, resulting in ambiguity among stakeholders. This paper aims to bridge this gap by thoroughly reviewing current destructive and non-destructive test methods for FRP pultruded materials, specifications, quality control, and health monitoring of FRP structures. Each subsection is further divided into subtopics, providing a comprehensive overview of the subject. By shedding light on these crucial aspects, this article aims to accelerate the adoption and utilization of these innovative materials in practical applications.
{"title":"Characterization Specifications for FRP Pultruded Materials: From Constituents to Pultruded Profiles","authors":"Ehsan Harati Khalilabad, Alvaro Ruiz Emparanza, Francisco De Caso, Hossein Roghani, Nima Khodadadi, Antonio Nanni","doi":"10.3390/fib11110093","DOIUrl":"https://doi.org/10.3390/fib11110093","url":null,"abstract":"Pultruded FRP composites have emerged as a promising alternative to traditional materials like concrete, steel, and timber, especially in corrosive environmental conditions. However, the unique properties of these composites necessitate careful consideration during their implementation, as they differ significantly from conventional materials. Proper testing and characterization of FRP pultruded materials is key for their efficient and safe implementation. However, the existing specifications are not unified, resulting in ambiguity among stakeholders. This paper aims to bridge this gap by thoroughly reviewing current destructive and non-destructive test methods for FRP pultruded materials, specifications, quality control, and health monitoring of FRP structures. Each subsection is further divided into subtopics, providing a comprehensive overview of the subject. By shedding light on these crucial aspects, this article aims to accelerate the adoption and utilization of these innovative materials in practical applications.","PeriodicalId":12122,"journal":{"name":"Fibers","volume":"1 8‐9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135973943","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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