Different Types Of Fibers Research Articles

Improving fire resistance of lightweight concrete facade elements by using fibers

It is known that the most critical factor affecting fire resistance requirements in buildings is the building envelope, and therefore, improving the thermal properties of facade materials has become an important research area. In this context, studies examining the high temperature resistance properties of various facade materials have indicated that concrete has higher heat resistance compared to many facade materials. Lightweight concrete facade elements stand out for their structural durability and fire resistance at high temperatures. However, the different thermal expansion coefficients of aggregates and cement paste in concrete mixtures can lead to adverse outcomes under high temperatures, such as cracking or structural degradation. To mitigate these adverse effects, it has been suggested that adding fibers to lightweight concrete mixtures could enhance durability and improve fire resistance. This study investigated the effects of different fiber types, lengths, and usage rates on the high temperature resistance of lightweight concrete mixtures. In the experimental study, three different types of fibers—polypropylene, polyamide, and glass—were used in varying proportions of 0%, 0.25%, 0.5%, and 0.75% of the total volume. Polypropylene fibers were included at lengths of 3, 6, and 12 mm; polyamide fibers at 6 and 12 mm; and glass fibers at 13 and 25 mm. When observing the behavior of the mixtures under high temperatures, it was noted that mixtures with glass fibers performed best at 300 °C, while those with polypropylene fibers showed superior performance at 600 °C. This demonstrates the advantages of glass and polypropylene fibers in providing resilience at different temperature ranges. Furthermore, the optimal fiber usage rate for high temperature resistance was determined to be 0.25%. These findings highlight the importance of considering factors such as fiber type, length, and usage rate in the development of fire-resistant facade materials.

Effects of Dietary Fiber Supplementation on Modulating Uremic Toxins and Inflammation in Chronic Kidney Disease Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Emerging evidence supports the beneficial effects of dietary fiber supplementation in alleviating gut dysbiosis, which leads to a reduction in uremic toxins and inflammatory markers in chronic kidney disease (CKD) patients. However, current evidence-based renal nutrition guidelines do not provide recommendations regarding dietary fiber intake. We performed a systematic review and meta-analysis to investigate and highlight the effects of dietary fiber supplementation on modulating uremic toxins and inflammatory markers in individuals with CKD, with or without dialysis. The eligible randomized controlled trials (RCTs) were identified from PubMed, Scopus, and Cochrane Central Register of Controlled trials until 27 November 2024. The results were synthesized using a random-effects model and presented as standardized mean differences (SMDs) with a 95% confidence interval (CI). A total of 21 studies with 700 patients were included. When compared with the control group, dietary fiber supplementation ranging from 6 to 50 g/day, for typically more than 4 weeks, could significantly reduce the levels of serum uremic toxins, including p-cresyl sulfate, indoxyl sulfate, and blood urea nitrogen (SMD −0.22, −0.34, −0.25, respectively, with p-values < 0.05), as well as biomarkers of inflammation, including interleukin-6 and tumor necrosis factor alpha (SMD −0.44, −0.34, respectively, with p-values < 0.05). These beneficial effects were consistent across different types of fibers and CKD status (with or without dialysis). However, no significant reduction in serum trimethylamine N-oxide, uric acid, and high-sensitivity C-reactive protein levels was observed with dietary fiber intervention. This study would pave the way for prioritizing dietary quality, particularly a fiber-rich diet, beyond the traditional focus on the quantities of protein, energy, and electrolyte restrictions among individuals with CKD.

Comprehensive Review: Optimization of Epoxy Composites, Mechanical Properties, & Technological Trends

Epoxy composites play a crucial role in modern materials technologies, with their exceptional properties such as high strength and thermal and chemical resistance, making them ideal for a wide range of industrial applications, including aerospace, automotive, construction, and energy. This review article provides a comprehensive overview of the current trends and advancements in epoxy composites, focusing on mechanical properties and their optimization. Attention is given to technological innovations, including the use of nanotechnologies, hybrid reinforcement, and eco-friendly materials, which are key to enhancing the performance and sustainability of these materials. The analysis shows that the introduction of nanomaterials, such as graphene, titanium dioxide, and silicon dioxide, can significantly improve the strength, fatigue resistance, and electrical properties of epoxy composites, opening new possibilities in advanced technologies. Another significant contribution is the development of hybrid composites, which combine different types of fibers, such as carbon, aramid, and glass fibers, enabling the optimization of key properties, including interlayer strength and delamination resistance. The article also highlights the importance of environmental innovations, such as bio-based resins and self-healing mechanisms, which enable more sustainable and long-term effective use of composites. The combination of theoretical knowledge with practical applications provides valuable guidance for designing materials with precisely defined properties for future industrial use. This text thus offers a comprehensive view of the possibilities of epoxy composites in the context of increasing demands for performance, reliability, and environmental sustainability.

Study on the Influence of Fibers to the Physical Mechanical Properties of Foam Concrete

Foam concrete has been widely used in building, infrastructure and fire prevention fields because of its lightweight, excellent heat and sound insulation performance. However, due to its high porosity, the compressive strength of foam concrete is usually low, which limits its application in some high-strength structures. In order to solve this problem, researchers improve the mechanical properties of foam concrete by adding different types of fiber materials. This paper summarizes the research progress of fiber on the performance of foam concrete, and analyzes the influence of different types of fiber (such as polypropylene fiber, basalt fiber, polyvinyl alcohol fiber, etc.) on the performance of foam concrete. The research shows that adding proper amount of fiber into foam concrete can effectively improve the mechanical, durability, dry shrinkage and other properties of foam concrete.

Influence of Different Fibers on Performance of Bitumen Binders and Thin-Overlay Bitumen Mixtures

Thin-layer covers easily crack under traffic load, shortening their service life. Incorporating fiber materials into the mix can enhance crack resistance thanks to their abundance, affordability, and flexibility. However, different types of fibers have different performances in bitumen and mixtures due to different material properties. To explore this problem, basalt fiber, polypropylene fiber, and glass fiber were selected in this paper. The surface characteristics, internal structure, and adsorption capacity of oily substances were observed via scanning electron microscopy and oil absorption rate testing. The effects of fibers on the high-temperature and low-temperature properties of styrene-butadiene-styrene block copolymer-modified bitumen were investigated using the dynamic shear rheometer and the force ductility method. Ultimately, through indirect tensile testing and semi-circular bending tests, and the introduction of the toughness index and fracture toughness, a comprehensive evaluation was conducted on how varying fiber types and content affect the crack resistance and toughness of bitumen mixtures. The results show that the density and dispersion of the bundle fibers are the key to the oil absorption capacity under similar internal and external structural conditions. The oil absorption rate of polypropylene fiber is the best, reaching 5.423. Fiber incorporation can significantly improve the high-temperature rheological properties of bitumen. At 4% dosage, G*/sinδ increased by about 107.04% on average at 76 °C. At low temperatures, the increase in fiber content leads to a decrease in bitumen elasticity, and the influence of glass fiber is more obvious. The area of toughness did not reach 2000 N·mm at 4% dosage. After adding fibers, the toughness index and fracture toughness of the mixture increased by more than 2% and 35%, respectively. The maximum increases in fracture energy and crack initiation energy of the mixture are 14.29% and 47.29%, respectively. It shows that the fiber enhances the toughness, crack resistance, and crack propagation resistance of the mixture. The research results can provide some reference for the application of fiber-reinforced bitumen mixtures.

Torsional Performance of Reinforced Concrete Beams Strengthened Using Hybrid Fibers Sifcon Jacketing

Abstract The main aim is to investigate the influence of hybrid fiber Slurry Infiltrated Fiber Concrete (SIFCON) strengthening of beams loaded under pure torsion. The volume percentage of fiber was constant at 5%. Seven beams underwent pure torsion testing after being cast., two beams were taken as a reference (The first one without torsional reinforcement and the second beam with torsional reinforcement), and five beams were strengthened by a SIFCON jacket, One beam fully jacketed, and four beams with three-side jacket. Different types of fiber (Steel, Glass, and Hybrid) used to cast SIFCON. It found that the increase in ultimate torsion by about (163 - 537) % for strengthened beams (no torsional reinforcement) and (46 - 254)% for beams with torsional reinforcement. Finally, the fully jacket-strengthening beam with 5% from steel fiber was the most effective among strengthening beams to improve torsion strength. In addition, the results of cracking torque, twist angle, Energy Absorption (Toughness), Torsional Stiffness, and torsional strength appear enhanced when using SIFCON different types of fiber in strengthened beams.

Effect of Natural Raw Fibers on Mechanical Properties of Fiber Reinforced Concrete: A Step Towards Sustainability

Abstract Concrete is the mostly used constructional material in industry and have versatile quality in nature. Fibrous concrete has significant factor that improve the scale and value to concrete for humid environments. Day by day abundant demand and use of concrete is increasing in construction industry. It is considered as a 2nd largest building material due to the major productivity. By the use of fibrous concrete, some bonding issues have been addressed and mitigate the environmental problems. Keeping in this view, an experimental based study is conducted to evaluate the strength of fiber reinforced concrete at different percentages 0%, 0.5%, 1.0%, 1.5% and 2.0%. All percentages are added by the weight of concrete with all fibers. In this connection, forty-five cylinders of five mixes are prepared. Workability checked of fresh concrete during the pouring of concrete cylinders. Poured cylinders’ samples are left for different curing ages at 7 and 28 days. Thirty cylinders for compression at 7 and 28days but fifteen cylinders for split tensile test at 28days with all fibers i.e. glass fiber, steel fiber, coconut fiber and polypropylene fiber. After curing, compression and split tensile tests are performed to check the strength of hardened concrete. Workability of five mixes lies between 40-90mm and compression strength is increased at 1% replacement with all fibers which is suitable for sustainable construction. Also, fibrous concrete is suitable for humid environment where high strength and voids less concrete are required like plaster in external walls and all structural components. Addition of fibers in concrete may improves the strength parameters as well as to increase the bonding and tensile properties of concrete. It reduces the quantity of water to be used in concrete. Also, the use of different types of fibers has been proved to be economical and is considered as environmentally friendly construction material.

Experimental Evaluation of Thermal Conductivity in Glass Fiber Reinforced Polymer Composites for Aerospace Applications

Abstract: This paper aims to study the thermal conductivity properties of GFRP composites and their prospect in aerospace sectors. GFRP composites are gradually becoming the material of choice in aerospace, given the properties of low density, high strength, and high durability. However, it is critical to comprehend their thermal properties for efficiency in habitats characteristic of aeronautical environments. The work will seek to assess and quantify the thermal conductivity of the GFRP composites and establish the influence of fiber orientation, volume fraction and temperature in the thermal properties of the composites. Composite samples were prepared from E-glass and epoxy-amine prepreg’s with controlled layup and post curing. Some important measures in this work were thermal conductivity, which was tested by a laser flash method, and depend on conditions, offering valid information. In general, findings show that fiber orientation plays a major role in determining the thermal conductivity of the samples examined, where the highest conductivity is recorded on the samples where the fiber orientation is parallel to the direction of heat transfer. Higher fiber volume fraction was also found to improve thermal conductivity. Moreover, the temperature dependence analysis showed a fly increase of thermal conductivity at high temperatures that suggests that the material is capable of handling temperatures stress. The results indicate that GFRP composites have the right thermal characteristic appropriate for aerospace application, especially where thermal management is crucial for a particular part. Thus, more research is advised that particularly emphasizes the use of different types of fiber, various types of polymer matrices as well as different hybrid composites suited for high stress conditions. This research provides important information concerning the application of GFRP composites in the aerospace sector, including the ongoing development of lightweight, insulating materials suitable for this sector.

Noise‐Like Pulse Seeded Supercontinuum Generation: An In‐Depth Review For High‐Energy Flat Broadband Sources

AbstractAs the need for compact, cost‐effective, and reliable laser sources continues to rise, fiber lasers have gained widespread interest in science and technology. In recent years, passively mode‐locked fiber lasers (PMLFLs) have emerged as pivotal tools for generating ultrashort pulses, propelling advancements across various domains including communication, manufacturing, medicine, defense, and security. Amongst the various types of lasing states supported by a PMFL, the emphasis in this review is on the noise‐like pulses (NLP) and their potential applications in supercontinuum generation (SCG). Interestingly, the quasi‐stationary operation of the NLP envelope containing numerous chaotic sub‐pulses has facilitated relatively high energy and broad bandwidth compared to standard mode‐locked laser pulses. Moreover, the NLP generation goes beyond a specific cavity arrangement, the nature of mode‐locking or cavity dispersion. Therefore, through this review, the foremost aim is to report the differences in NLPs across various experimental settings reported so far and highlight the strategies beneficial for high‐energy and broadband NLP development directly from a fiber oscillator. Secondly, the application of NLP as a seed laser is examined to stimulate SCG in different types of fibers, underlining the improved supercontinuum characteristics over the conventional ultrashort pulse pumping schemes. Finally, the benefit of NLP‐seeded SCG for various bio‐medical and industrial applications are highlighted, thanks to the broader and flatter continuum achievable through compact experimental settings.

An Experimental Study on the Compressibility of Clays Reinforced with Basalt Fiber

The use of basalt fiber has become quite common in soil reinforcement works, which emerged as an alternative to traditional soil improvement methods and are carried out using different types of fibers. Basalt fiber, whose raw material is basalt rock, is preferred in soil reinforcement works due to its features such as high strength, economical, environmentally friendly, natural and abundant. In this study, the effects of basalt fiber reinforcement on the compressibility of high plasticity bentonite clay were examined. Bentonite clay was reinforced with 24 mm long basalt fiber at different rates between 0.5% and 5.0%, and standard proctor tests were carried out on these mixtures. With experimental studies, maximum dry density (γdmax) and optimum water content (Ꞷopt) values were determined and the effects of basalt fiber reinforcement on these parameters were evaluated. According to the test results, while γdmax values increased up to 2.5% basalt fiber reinforcement ratio, Ꞷopt values decreased. In samples with basalt fiber ratio greater than 2.5%, γdmax values decreased and Ꞷopt values increased. The results obtained showed that the basalt fiber ratio at which bentonite can be compressed best is 2.5%, and basalt fiber reinforcement at rates greater than this ratio negatively affects the compressibility.

Development of a novel DNA-shaped steel fiber and its performance on fresh and hardened concrete

Adding small discrete random fibers in concrete has enhanced concrete behavior in various ways. Diverse types of fibers are available in terms of materials, shapes, and applications. Different shapes of steel fibers are available like hooked ends, crimped, stranded, helix, spherical, etc. Having the grade of concrete and the fiber dosage added as constant, the structural behavior and performance will vary for different types of fibers. It shows that the shape of fiber has a great role in enhancing the properties of concrete. The challenges in existing two-dimensional steel fibers in concrete like the mechanism and contribution of fiber in arresting cracks developed in all directions and balling effect can be overcome by a new type of three-dimensional steel fiber. A novel three-dimensional DNA-shaped steel fiber is designed and fabricated. This paper presents the fresh concrete and hardened concrete properties of DNA-shaped fiber-reinforced concrete (DNAFRC) and compares it with hooked-end fiber-reinforced concrete (HEFRC) by incorporating a volume fraction varying from 0.5 % to 2 % of grade M30 concrete and aspect ratio of 60 for both fibers. The fresh properties of concrete were evaluated by measuring the slump for workability and wash-out test for the fiber distribution. The hardened concrete properties were assessed by compressive, split tensile, flexural, impact, shear, and pull-out strength which demonstrated considerable increase by 5 % at 1.5 % volume fraction, 32 %, 136 %, 21 %, and 35 % at 2 % volume fraction respectively for DNAFRC than the HEFRC. Scanning Electronic Microscope (SEM) images were studied on failed samples to evaluate the bonding of DNA fiber with concrete.

Mechanical Properties of Full-Scale Wooden Beams Strengthened with Carbon-Fibre-Reinforced Polymer Sheets

The strengthening, rehabilitation and repair of wooden beams and beams made of wood-based materials are still important scientific and technical issues. This is reflected, among other things, in the number of scientific articles appearing and the involvement of research centres around the world. This is also related to society’s growing belief in the importance of ecological and sustainable development. This article presents an overview of the latest work in this field and the results of our own research on strengthening solid wooden beams with carbon-fibre-reinforced polymer (CFRP) sheets. The tests were carried out on full-size solid beams with nominal dimensions of 70 × 170 × 3300 mm. A 0.333 mm thick CFRP sheet was used for reinforcement. The research analysed various reinforcement configurations and different reinforcement ratios. For the most effective solution, a 46% increase in load capacity, 35% stiffness and 249% ductility were achieved with a reinforcement ratio of 1.7%. Generally, the higher the reinforcement ratio and coverage of the surface of the wood, the higher the strengthening effectiveness. The brittle fracture of wood in the tensile zone for unreinforced beams and the ductile crushing of wood in the compressive zone for reinforced beams were obtained. The most important achievement of this work is the description of the static work of beams in previously unanalysed configurations of strengthening and the confirmation of their effectiveness. The described solutions should extend the life of existing wooden buildings and structures and increase the competitiveness of wooden-based structures. The results indicate that, from the point of view of optimizing the cost of reinforcement, it is crucial to develop cheaper ways of combining wood and composite than to verify different types of fibres.

Trio/hybrid fiber effect on the geopolymer reinforced concrete for flexural and shear behavior

AbstractGeopolymer concrete (GC) is an innovative and sustainable type of composite resulting from the chemical reaction between waste materials containing and alkaline activators. The researchers have been focused to reduction of the greenhouse‐gas release, especially during the production of cement. Although numerous studies have been conducted on alkali‐activated cement or GC at the material level, there is limited research in the literature on the structural performance of reinforced GC members. The aim of this study is to investigate the effect of fiber combination on the shear and flexural performance of RC beams with maximum and minimum reinforcement ratio. To investigate the shear and flexural behavior of GC beam, four‐point and three‐point tests were performed on 12 GC with hybrid fibers, 4 GC with trio fibers, and 2 GC fiber‐free as references beams. The test parameters were the combination of fibers (steel, glass, carbon, and basalt), the longitudinal reinforcement ratio, and loading type. The key test results include the load‐deflection behavior, characteristics of the cracks, the effect of fiber type on the shear and flexural performance, ductility and stiffness properties, microstructure, the strain in the concrete, and the bars and code predictions. The test results showed that as expected, reducing the longitudinal reinforcement ratio decreased the strength, but the decrease in strength was tolerated by using different types of fibers. The use of trio fibers in beams under bending increased the strength capacity, considerably. Finally, the capacity prediction performance of current codes, that is, GB50010, EuroCode‐2, TS500, and ACI318, were also examined, and the calculations resulted that the current code equations had a percentage error of approximately 25% and 82% on average for flexural and shear, respectively, although EuroCode‐2 equations performed slightly better.

A review of current analytical methods for the determination of dietary fiber in food

Fiber benefits health and is an essential requirement in the body's daily diet. The definition of fiber has been evolving over the past 70 years. Initially, the definition of fiber focused only on plant cell walls (cellulose, hemicellulose, pectin, cutin, glycoprotein) and intracellular storage and secretion substances (gum, mucilage). More recently, the world has focused on resistant starch and oligosaccharides. The CODEX definition of dietary fiber includes all non-digestible carbohydrate polymers with a degree of polymerization of 3 or higher, provided that they benefit health. Fiber has many components, requiring the development of different methods to analyze components such as fructo-oligosaccharide, galacto-oligosaccharide, polydextrose, resistant maltodextrin, resistant starch, etc. A series of AOAC methods have been developed to explore different types of fiber, and these methods are still valid and widely used. For the analysis of total fiber content, the enzymemass method according to Prosky (AOAC 985.29) was considered the gold standard when it was first published. However, this method only determines a part of the fiber. When adding up the specific fiber components calculated from different methods, some types of fiber are double counting. Therefore, the method for determining total fiber is constantly updated and revised. The Enzymatic-Gravimetric-Liquid Chromatography method has been developed and can fully determine the components of dietary fiber; the newly published updated version is AOAC 2022.01.

EXPERIMENTAL STUDY ON COMPRESSIVE STRENGTH AND SHEAR STRENGTH OF MASONRY UNIT WITH FIBER GLASS AND POLYPROPYLENE FIBER PAINT COATING

In this study, the effects of fiber layers on the compressive and shear strength properties of masonry are investigated. The aim is to improve the mechanical properties of masonry walls that are prone to earthquakes The experimental investigations provide information on the mechanical properties of Indonesian masonry blocks under two conditions: without and with fiber coating. Two different types of fibers were used in this study: Fibreglass and Polypropylene fiber. The fiber content is 8% for 1 kg of paint with 5% water. The thickness of the coating applied to the masonry ranges from 1 mm to 3 mm. The compressive strength of the samples with a layer of polypropylene fibers with a thickness of 1 mm and 3 mm is 30.32 kg/cm², 31.16 kg/cm² and 47.16 kg/cm², respectively. The compressive strength of the samples with a layer of glass fiber paint with a thickness of 1 mm, 2 mm, and 3 mm is 30.1 kg/cm², 31.22 kg/cm², 53.31 kg/cm² and the value of the control sample is 25.89 kg/cm². The shear strength of masonry with polypropylene-coated fiber with a layer thickness of 1 mm, 2 mm, and 3 mm is 3.93 kg/cm², 4.64 kg/cm², and 5.89 kg/cm². The bricks reinforced with glass fiber paint with a layer thickness of 1 mm, 2 mm, and 3 mm have 3.77 kg/cm², 5.31 kg/cm², and 5.05 kg/cm².

Application of the Optical Fiber Diameter Analyzer for Assessing Cotton Fiber Ribbon Width

ABSTRACT Existing methods for measuring fineness are time-consuming, tedious, and impractical to evaluate many samples. For this reason, the Textile Industry has sought a rapid, accurate, and reliable instrument to determine fiber fineness. Recently, the Optical Fiber Diameter Analyzer (OFDA) was introduced for rapid and precise evaluation of the diameter of different types of fibers. In this study, the OFDA was evaluated for measuring the ribbon width of cotton fiber snippets. One hundred and four carded cotton samples covering a wide range of fiber properties were selected and tested with nine replications per sample. The repeatability of the OFDA diameter measurement was confirmed. Comparisons with the data (cross-sections, AFIS, and Cottonscope) obtained from previous studies on the 104 samples were used to assess the effectiveness of the proposed method. The relationship between ribbon widths measured by Cottonscope and OFDA was found to be weak. Yet, there is a strong correlation between OFDA ribbon width and AFIS standard fineness. We hypothesize that the poor relationship between the Cottonscope and the OFDA is related to the medium in which the measurements are performed. The results are stable and provide measurements closely related to AFIS standard fineness, a trusted measurement within the Textile Industry.

Modeling of the effect of fibers on ECC slurry fluidity based on an amended water film thickness theory

Knowing the influence mechanisms of fibers on ECC slurry fluidity and implementing the prediction of ECC slurry fluidity attach vital significance to the design and application of ECC. Based on traditional water film thickness (WFT) theories, this paper introduces the difference in surface WFT of reactive fibers and binding material particles with excess water distribution coefficient and further gives a modified formula for water film calculation and a WFT based ECC fluidity model. Through 40 tests and fitting, the excess water distribution coefficient with respect to distinct fibers and relevant parameters of the ECC fluidity model are obtained. The results indicate that the new model is applicable to different types of fibers, and the fluidity of ECC slurry can be described using an equation, with the R2 of the new equation reaching 0.97. Finally, based on the proposed model, the impact of PP and PVA fibers on the fluidity of ECC slurry can be summarized in two aspects: the wedge effect of the fibers reduces the packing density of the ECC powder, leading to a decrease in the excess water ratio; the water distribution in the ECC slurry is altered by the fibers, resulting in a decrease in the water film thickness on the surface of the cementitious material particles, ultimately causing a decline in the fluidity of the ECC slurry.

Three dimensional simulations of FRC beams and panels with explicit definition of fibres-concrete interaction

High performance concrete (HPC) is a quite novel material which has been rapidly developed in the last few decades. It exhibits superior mechanical properties and durability comparing to normal concrete. HPC can achieve also superior tensile performance if strong fibres (steel or carbon) are implemented in the matrix. Thus, there exist the unabated interest in studying how the addition of different types of fibres modifies the behaviour of HPC. Nowadays, a standard numerical approaches to model the behaviour of fibre reinforced concrete (FRC) are carried out by means of the smeared or discrete crack modelling of homogenous media with appropriately changed stress-strain relationships. The objective of this paper is to develop a new and efficient mesoscale modelling approach for steel fibre reinforced high-performance concrete. The main idea of presented approach is to assume the fully 3D modelling with taking into account explicitly the distribution and orientation of the steel fibres. As a benchmark, results obtained from experimental campaign on beams and panels made from high-performance concrete with steel fibres of different sizes and dosages were taken. Results of numerical simulations were directly compared with experimental outcomes in order to validate and calibrate FE-model and to introduce the efficient numerical modelling tool.

Forensic discrimination of fiber microspectrophotometry data by resampling and repeating two-sample hypothesis testing

Textile fibers are important forensic trace evidence in criminal investigations. Colored textile fibers are often analyzed using non-destructive microspectrophotometry. However, when the spectra of questioned and known samples are very similar, it is difficult to compare the spectra visually. Chemometric methods, such as principal component analysis and agglomerative hierarchical clustering, have been applied to microspectrophotometry data. In this study, we used two-sample hypothesis testing as a chemometric approach for discrimination of fiber samples without reducing or eliminating the dimensionality of the data. Cotton fibers dyed with vat dyes were analyzed by microspectrophotometry. We examined suitable data types and statistical methods for test fiber samples by resampling and repeating hypothesis testing. A combination of spectral data type and statistical method was identified that provided a good balance of type I (false exclusion) and type II (false inclusion) error rates in two-sample hypothesis testing of the fibers.The main advantage of our chemometric approach is that an appropriate method for samples can be selected by using the type I and II error rates. Furthermore, our method can use all the measured data for the calculation without reducing or eliminating the dimensionality of the data, so it is not necessary to reduce variables or smooth the spectrum. This statistical method also requires no training set. Therefore, two-sample hypothesis testing could be applied to fibers of different types, colors, or materials from those used in this study. Resampling and repeating two-sample hypothesis testing technique is promising as a new chemometric approach for comparing microspectrophotometry spectra.

Effect of fiber types on fire-induced spalling and thermal performance of UHPC circular columns

Ultra-high-performance concrete (UHPC) emerged as a promising material for modern construction, offering unparalleled strength, durability, and versatility. However, there is limited research regarding UHPC's response to fire, prompting urgent investigation and analysis. This paper presents an experimental study focused on evaluating the effect of different types of fibers on the fire performance of UHPC circular columns. The fiber types considered in this study included steel fibers (SF), a hybrid mix of steel and polypropylene fibers (SPPF), and polyvinyl alcohol fibers (PVAF). Additionally, a control column was cast without the inclusion of any fibers. All UHPC specimens were subjected to standard fire exposure, following the ASTM E119 fire test. The results indicated a substantial resistance to spalling with the incorporation of fibers. Moreover, the column featuring PVAF exhibited the lowest internal temperature readings among the columns. Columns reinforced with SF and SPPF exhibited uniform spalling on all sides.