Arrangement Of Fibers Research Articles

Fabric-like bacterial cellulose for textile applications – analysis of influences between physical and thermal dehydration on end-use performance

When researching practical applications for fashion, healthcare, and others of Bacterial Cellulose (BC), dehydration of BC is currently emphasized as one of its primary limits, which reduces the material’s attractiveness in these fields. This work explored the effects of physical and thermal dehydration methods on dehydration effectiveness, rehydration, appearance, structure, and morphology. Squeezing employing the padding method results in the most effective dehydration for mass and thickness loss (97.76 ± 0.31% and 98.29 ± 0.32%, respectively), which is advantageous for productivity (roundly 108-432 times faster than freeze-drying and 105 °C convection drying). Fabric-like BC produced possesses a good appearance, oriented fiber arrangement, fabric-embossing surface, thin thickness (0.27 ± 0.06 mm), water absorbency (11.93 ± 1.09 weight times), strong bursting strength, water vapor transmission, resistance to water penetration, and proactive moisture content selection. Fabric-like BC, therefore, will uncover tremendous potential applications of textile finishing and dyeing for modification and functionalization in environment-friendly, and productive ways and make progress in BC dehydration.

Lactobacillus fermentum attenuates the alveolar bone loss in ligature-induced periodontitis in mice.

This study investigated the effects of Lactobacillus fermentum BELF11 on periodontitis in mice (LIP). Sixty mice were randomly assigned to a control group (CTL), LIP/PBS group (LIP and PBS applied), or LIP/BELF11 group (LIP and L. fermentum BELF11 applied). For 14 days, PBS or L. fermentum BELF11 was applied twice daily to the mice in the LIP/PBS or LIP/BELF11 group, respectively. After 14 days, radiographic, histological, and pro-inflammatory cytokine assessments were conducted. The LIP/PBS and LIP/BELF11 groups demonstrated greater alveolar bone loss than the CTL group (p < 0.05). The LIP/BELF11 group showed significantly reduced alveolar bone loss on the mesial side compared to the LIP/PBS group. Histologically, the LIP/BELF11 group showed consistent patterns of connective tissue fiber arrangement, lower levels of inflammatory infiltration, less alveolar bone loss, and higher alveolar bone density than the LIP/PBS group, despite showing more signs of destruction than the CTL group. The LIP/BELF11 group also exhibited significantly lower levels of pro-inflammatory cytokines than the LIP/PBS group. L. fermentum BELF11 inhibits alveolar bone loss and periodontitis progression by regulating pro-inflammatory cytokine production. These findings suggest that L. fermentum BELF11 may be a potential adjunctive therapy in periodontal treatment.

MiR-141-3p-Functionalized Exosomes Loaded in Dissolvable Microneedle Arrays for Hypertrophic Scar Treatment.

Hypertrophic scar (HS) is a common fibroproliferative disease caused by abnormal wound healing after deep skin injury. However, the existing approaches have unsatisfactory therapeutic effects, which promote the exploration of newer and more effective strategies. MiRNA-modified functional exosomes delivered by dissolvable microneedle arrays (DMNAs) are expected to provide new hope for HS treatment. In this study, a miRNA, miR-141-3p, which is downregulated in skin scar tissues and in hypertrophic scar fibroblasts (HSFs), is identified. MiR-141-3p mimics inhibit the proliferation, migration, and myofibroblast transdifferentiation of HSFs in vitro by targeting TGF-β2 to suppress the TGF-β2/Smad pathway. Subsequently, the engineered exosomes encapsulating miR-141-3p (miR-141-3pOE -Exos) are isolated from adipose-derived mesenchymal stem cells transfected with Lv-miR-141-3p. MiR-141-3pOE -Exos show the same inhibitive effects as miR-141-3p mimics on the pathological behaviors of HSFs in vitro. The DMNAs for sustained release of miR-141-3pOE -Exos are further fabricated in vivo. MiR-141OE -Exos@DMNAs effectively decrease the thickness of HS and improve fibroblast distribution and collagen fiber arrangement, and downregulate the expression of α-SMA, COL-1, FN, TGF-β2, and p-Smad2/3 in the HS tissue. Overall, a promising, effective, and convenient exosome@DMNA-based miRNA delivery strategy for HS treatment is provided.

Comparison of the Eggshell and the Porcine Pericardium Membranes for Guided Tissue Regeneration Applications.

Guided bone regeneration is frequently used to reconstruct the alveolar bone to rehabilitate the mastication using dental implants. The purpose of this article is to research the properties of eggshell membrane (ESM) and its potential application in tissue engineering. The study focuses on the structural, mechanical, and histological characteristics of ESM extracted from Gallus domesticus eggs and to compare them to a commercially available porcine pericardium membrane (Jason® membrane, botiss biomaterials GmbH, Zossen, Germany). Thus, histology was performed on the ESM, and a comparison of the microstructure through scanning electron microscopy and atomic force microscopy (AFM) was conducted. Also, mechanical tensile strength was evaluated. Samples of ESM were prepared and treated with alcohol for fixation and disinfection. Histological analysis revealed that the ESM architecture is constituted out of loose collagen fibers. However, due to the random arrangement of collagen fibers within the membrane, it might not be an effective barrier and occlusive barrier. Comparative analyses were performed between the ESM and the AFM examinations and demonstrated differences in the surface topography and mechanical properties between the two membranes. The ESM exhibited rougher surfaces and weaker mechanical cohesion attributed to its glycoprotein content. The study concludes that while the ESM displays favorable biocompatibility and resorb ability, its non-uniform collagen arrangement limits its suitability as a guided bone regeneration membrane in the current non-crosslinked native form. Crosslinking techniques may enhance its properties for such applications. Further research is needed to explore modifications and processing methods that could leverage the ESM's unique properties for tissue engineering purposes.

A new quantitative method to evaluate the spatial distribution of fibres in composites: the degree of randomness

A new quantitative method, the D-index, is proposed to evaluate the departure of a given fibre arrangement from the completely spatial randomness (CSR) pattern. An explicit model which can effectively control the degree of randomness (DoR) is created to investigate the correlation between the D-index and DoR. The theory behind the correlation is analyzed followed by the derivation of first and higher order D-index with respect to the DoR under different fibre volume fractions. This may be the first time an accurate value of the departure from randomness is provided, which is considered important for accurate micro-mechanical analysis.

Mechanical Properties of Light-Transmitting Concrete and Its Durability Performance under the Effects of Accelerated Aging

Abstract Although concrete has been used extensively as a structural material for buildings since ancient times, light-transmitting concrete (LTC), also referred to as translucent concrete, is an innovative and attractive building material for the construction industry to enhance aesthetic and energy-saving properties. This research paper aims to investigate the mechanical properties of LTC with different optical fiber arrangements with three optical fiber ratios, respectively, 1, 1.6, and 2.4 %. The durability performance of LTC under the effects of accelerated aging is also investigated. Polymethyl methacrylate (PMMA) optical fibers with two arrangements were used in the concrete specimens. One of the LTC groups that had a linear optical fiber arrangement was labeled as ARlin. The other LTC group with bundle optical fiber arrangements was labeled as ARbun. The prepared concrete consisted of cement, fine aggregate, water, mineral additive, acrylic polymer, and superplasticizer. The flexural strengths of LTC with PMMA optical fibers placed longitudinally or laterally were determined. The compressive strengths of LTC specimens with different arrangements were compared. Accelerated aging effects under wetting-drying, freezing-thawing, and high temperature were applied to the ARlin group to investigate these effects on the mechanical properties of LTC. The results of the experiments indicate that the optical fiber arrangements affect the flexural strength, compressive strength, and light transmittance of LTC. The light transmittance increases with the optical fiber content. It is also seen that the flexural strengths and light transmittance of LTC specimens decrease significantly after the high-temperature effect. According to the test results, it is also concluded that LTC with 0.5-mm-diameter optical fibers in a linear arrangement can be used as a construction material under external conditions.

Degradation of Polyester Composite Reinforced E-Glass Fiber with Calcium Carbonate Filler in Seawater

This research is concerned with composite materials that use CaCO3 as a reinforcing material in construction, especially subsea panels and buildings. Composite materials are solids composed of two or more materials that have their own properties and improve their properties when combined. In this experiment, glass fiber and CaCO3 were mixed in a certain composition and tested to evaluate the water absorption and mechanical strength of the composite. The results show that increasing temperature can increase water absorption, while the addition of CaCO3 has a significant effect on water absorption due to its hydrophilic properties. Water absorption in polyester composites is influenced by aging temperature and Calcium Carbonate powder filler, affecting tensile and bending strength. As aging temperature increases, mechanical strength decreases, composite having the highest tensile strength. Bending tests show debonding and splitting fault patterns due to glass fiber arrangement. With a deeper understanding of how CaCO3 affects composite materials under various conditions, this research can provide valuable insights for developing more durable composite materials suitable for construction applications, especially in corrosive environments such as subsea buildings.In this research, it proposes theoretically model to controlling on half-wave voltage of modulator, in which it uses studying the factor of effective of refractive index difference, this using analysis distribution of refractive index for LN material before and after voltage is applied (i.e., with and without applied voltage), and uses analysis a factor of propagation constant difference ??, before and after voltage is applied where it depends on the wavelength, these leads to it controls on the half-wave voltage V? using a reduction half-wave voltage up to 1V. Also, it achieves an excellent solution for solve the fundamental optical mode with effective factor is neff. Finally, the modulator with an effect effective refractive index difference have lower applied voltage up to 10V, and with an effective propagation constant difference the operating voltage is from value of 20V.

Experimental and numerical analysis of the pyrolysis dynamics of a single wood particle: presentation of the radiographic technique

Pyrolysis is an oxygen-free process for the thermal decomposition of raw materials. The heat conduction and flow of pyrolysis products (i.e., the gas fraction and liquid vapour generated during pyrolysis) influence the process and products. In this work, the influence of the orientation of wooden particle fibres with respect to the direction of the heat source on the dynamics of the process was investigated, where there were two particle sizes oriented along or across the heat source. The novelty of this work lies in the use of a radiographic technique for analysing the influence of wooden fibres' orientation on the degradation process. The research showed that during pyrolysis, the mass loss rate in the particles with fibres oriented across the heat source and along the heat source was different. A similar tendency was characteristic for the drying process. The dynamics of pyrolysis of a single wood particle depends on many factors—particle size, process parameters, arrangement of fibres in wood, etc. The analysis of the dynamics presented in the publications is based on the analysis of the dynamics of mass loss, which is a very large simplification. The publication contains experimental analysis and mathematical calculations of the pyrolysis process for samples of various sizes and samples with different fibre arrangement. The result of the research is the determination of trends regarding the shape of the particle and the arrangement of fibres on the process, which provides knowledge that can be translated into industrial pyrolysis processes.

Emergency cesarean section in dogs: Usefulness of amniotic fluid biochemical parameters and placental morphology as indicators of neonatal viability

In recent years, special attention has been paid to the analysis of fetal fluids and placental histopathology to identify parameters that can be used as indicators of maternal reproductive quality, embryonic viability, and fetal and neonatal health. Newborn health reflects the functioning of the fetal adnexa and its relationship with maternal tissues. Therefore, evaluating these components is promising for the early detection of newborns at risk. This study aimed to detect the biochemical characteristics of the amniotic fluid (AF) and histopathological characteristics of the placenta for comparison between canine neonates born by elective (EL) and emergency (EM) cesarean sections (CSs) and associate the results with neonatal viability in the first 24 h. A total of 38 neonates born by ELCS (n = 19) and EMCS (n = 19) were selected. AF was collected to analyze the concentration of its biochemical components [alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatinine, urea, total protein, albumin, total and direct bilirubin, lactate, glucose, potassium, chloride, calcium, and sodium]. Histopathological processing of the placenta was used to describe the lesions and identify the arrangement of collagen fibers using hematoxylin-eosin and picrosirius staining. There was an increase in ALP activity (P = 0.035) and the concentrations of lactate (P < 0.001) and potassium (P = 0.031), and a decrease in chlorides (P < 0.001) in the AF of neonates in the EMCS group. The comparisons between the groups did not show differences between the presence and extent of lesions in the placenta; however, a difference was observed in the arrangement of collagen fibers in the placental structure. A comparison between AF and histopathological findings showed a negative correlation (r = −0.609, P = 0.003) between glucose concentration and the presence of necrosis in the placental labyrinth. It was observed that the composition of the AF changed owing to the influence of the type of cesarean, possibly caused by prolonged hypoxia in cases of dystocia. ALP activity and lactate, potassium, and chloride concentrations in the AF might be explored as markers of neonatal health in EMCS. Under the conditions of this study, no correlations were found between the placenta's histopathological characteristics and the neonates' viability.

Radiofrequency energy in the treatment of erectile dysfunction-a novel cohort pilot study on safety, applicability, and short-term efficacy.

The erectile mechanism depends, in part on the intactness of the collagen components in the penis. As such, impaired collagen may have a deleterious effect on erectile function. Radiofrequency energy has been shown to renew and restore spatial structural arrangement of collagen fibers; therefore, treatment of erectile dysfunction with radiofrequency could lead to anatomical and physiological changes at the penile tissue level and could lead to improvement in the erectile mechanism. We conducted this study to assess the effect of radiofrequency treatment on erection quality. We evaluated the safety, applicability, and efficacy of a self-applied, handheld, low-intensity radiofrequency device (Vertica®) in men with moderate and mild-to-moderate organic erectile dysfunction. The treatment protocol consisted of 12 treatments (twice a week during the 1st month, and once a week during the 2nd month), and each participant treated himself individually. Treatment outcomes were evaluated using the International Index of Erectile Function, Erection Hardness Scale, Erectile Dysfunction Index of Treatment Satisfaction, Benefit, Satisfaction & Willingness to continue, Quality of Erection Questionnaire, Sexual Quality of Life questionnaires and specific questions addressing side effects and ease of use. Twenty-eight out of 32 men (mean age 59.5 ± 9.8, range: 41-78 years) completed a one-month follow-up after treatment. Mean International Index of Erectile Function (43.7. ± 7.8 vs. 60.9 ± 10.8, p < 0.01), International Index of Erectile Function -Erection Function domain (16.8 ± 3.1 vs. 24.4 ± 4.4, p < 0.001), and Erection Hardness Scores (2.2 ± 0.8 vs. 3.2 ± 0.5, p = 0.01) were all significantly improved. Fifty percent of patients achieved normal erectile function parameters according to the International Index of Erectile Function -Erection Function domain score >25. High mean scores were achieved in the Erectile Dysfunction Index of Treatment Satisfaction (76.8 ± 20.3), Benefit, Satisfaction & Willingness to continue (4.83 ± 1.1), Quality of Erection Questionnaire (73.4 ± 23.8), and Sexual Quality of Life (67 ± 29.4) questionnaires. No side effects were reported and participants rated the device as very comfortable, simple, and easy to operate.

Electrospun Membrane Fabrication in Assisting Tissues Healing

The arrangement of fibers into three-dimensional (3D) complex structure is constructing a sheet of membrane, depending on the fabrication technique. The fiber mats and scaffolds have been used in various applications including tissue engineering which involve the integration of cells and tissues within the pores between the fibers. There are several techniques that have been opted to produce specifically nanofibers as its efficacy in tissue healing is prominent compared to microfibers. Among the fabrication techniques (drawing, template synthesis, temperature-induced phase separation, molecular self-assembly, and electrospinning), electrospinning method has drawn attention due to their easy handling, inexpensive, and ability for membrane scale-up with the production of fibers ranging from few nanometers to several microns. Researchers have employed a variety of electrospinning methods, including blended/co-electrospinning, emulsion, coaxial, side-by-side, and triaxial electrospinning. In electrospinning smooth formation of nanofibers for tissue healing with less appearance of spray and beads, several parameters such as humidity, temperature, voltage, flow rate, viscosity, concentration, molecular weight, surface tension, conductivity, and solvent volatile need to be tailored. The morphology of nanofibers formation should support the size and structure of the surrounded cells and tissues. Besides, the types of degradable polymeric materials also play a role in the formation of stable nanofibers. This review paper aimed to provide information on the techniques to produce nanofibers, intended to the basic exploration of electrospinning.

Comparative analysis between Graphene and Carbon Nanotube reinforced epoxy composite

Composite structures are very high in demand because of their high strength-to-weight ratio and directional strength. The arrangement of fibers in the matrix is the major design criterion for the composites. Past studies prove that the fiber reinforcement of carbon nano allotropes such as Carbon Nanotubes (CNTs) and Graphene fibers develop reliable and durable structures for different applications. In this work, three different composite laminate sheets are designed and modeled using finite element analysis (FEA) software. Carbon nano allotropes, CNTs, Graphene, and CNT-Graphene fibers are used as reinforcements in the resin epoxy matrix. The modeled laminate sheets are analyzed for deformation and stress distribution using Hashin’s Failure criteria. The FEA results indicate that the CNTs fiber-reinforced laminate shows minimum deformation (0.000064 mm) and experiences minimum stress (3.81 MPa) compared to Graphene and CNT-Graphene reinforced laminates. The results of FEA can be used as a research basis for further study of composites in the future.

Оценка качественных признаков древесины в селекционных программах (краткий обзор современной литературы)

The literature review concerning wood quality traits measuring in forest tree breeding programs is given. Methods of wood density measuring by Pilodin and different types of Resistograph are shortly described. Comparison study to measure Scots pine wood density by Pilodin and Resistograph revealed that Resistograph provide more precise wood density data than Pilodin. Method of measuring of wood stiffness an important wood mechanical property using acoustic velocity data is characterized. There is relationship between distortion of lumber and grain angle of wood fibers. Grain angle, i.e. spiral grain, refers to the degree of helical deviation from longitudinal arrangement of wood fibers. It can be measured with a wedge grain angle gauge hammered into a stem of a standing tree. It is shown, that microfibril angle (MFA), referring to the deviation of cellulose microfibrils in the layer of the secondary cell wall from the long axis of cell, is the main determinant of the mechanical properties of wood. There is shortly described the system of instruments with linked software (SilviScan), the main components of this system are optical cell scanner (for measurement of fiber size), X-ray densitometer (density profile and others) and X-ray diffractometer (microstructure traits). A minor negative relationship between growth and wood quality traits is noted, so the index selection is recommended under realization of tree breeding program. Some examples of genomic selection in tree breeding programs for wood quality are given.

HNRNPC promotes collagen fiber alignment and immune evasion in breast cancer via activation of the VIRMA-mediated TFAP2A/DDR1 axis

BackgroundCancers aggressively reorganize collagen in their microenvironment, leading to the evasion of tumor cells from immune surveillance. However, the biological significance and molecular mechanism of collagen alignment in breast cancer (BC) have not been well established.MethodsIn this study, BC-related RNA-Seq data were obtained from the TCGA database to analyze the correlation between DDR1 and immune cells. Mouse BC cells EO771 were selected for in vitro validation, and dual-luciferase experiments were conducted to examine the effect of TFAP2A on DDR1 promoter transcription activity. ChIP experiments were performed to assess TFAP2A enrichment on the DDR1 promoter, while Me-RIP experiments were conducted to detect TFAP2A mRNA m6A modification levels, and PAR-CLIP experiments were conducted to determine VIRMA’s binding to TFAP2A mRNA and RIP experiments to investigate HNRNPC’s recognition of m6A modification on TFAP2A mRNA. Additionally, an in vivo mouse BC transplant model and the micro-physiological system was constructed for validation, and Masson staining was used to assess collagen fiber arrangement. Immunohistochemistry was conducted to identify the number of CD8-positive cells in mouse BC tumors and Collagen IV content in ECM, while CD8 + T cell migration experiments were performed to measure CD8 + T cell migration.ResultsBioinformatics analysis showed that DDR1 was highly expressed in BC and negatively correlated with the proportion of anti-tumor immune cell infiltration. In vitro cell experiments indicated that VIRMA, HNRNPC, TFAP2A, and DDR1 were highly expressed in BC cells. In addition, HNRNPC promoted TFAP2A expression and, therefore, DDR1 transcription by recognizing the m6A modification of TFAP2A mRNA by VIRMA. In vivo animal experiments further confirmed that VIRMA and HNRNPC enhanced the TFAP2A/DDR1 axis, promoting collagen fiber alignment, reducing anti-tumor immune cell infiltration, and promoting immune escape in BC.ConclusionThis study demonstrated that HNRNPC promoted DDR1 transcription by recognizing VIRMA-unveiled m6A modification of TFAP2A mRNA, which enhanced collagen fiber alignment and ultimately resulted in the reduction of anti-tumor immune cell infiltration and promotion of immune escape in BC.

Structural and functional heterogeneity of mineralized fibrocartilage at the Achilles tendon-bone insertion.

A demanding task of the musculoskeletal system is the attachment of tendon to bone at entheses. This region often presents a thin layer of fibrocartilage (FC), mineralized close to the bone and unmineralized close to the tendon. Mineralized FC deserves increased attention, owing to its crucial anchoring task and involvement in enthesis pathologies. Here, we analyzed mineralized FC and subchondral bone at the Achilles tendon-bone insertion of rats. This location features enthesis FC anchoring tendon to bone and sustaining tensile loads, and periosteal FC facilitating bone-tendon sliding with accompanying compressive and shear forces. Using a correlative multimodal investigation, we evaluated potential specificities in mineral content, fiber organization and mechanical properties of enthesis and periosteal FC. Both tissues had a lower degree of mineralization than subchondral bone, yet used the available mineral very efficiently: for the same local mineral content, they had higher stiffness and hardness than bone. We found that enthesis FC was characterized by highly aligned mineralized collagen fibers even far away from the attachment region, whereas periosteal FC had a rich variety of fiber arrangements. Except for an initial steep spatial gradient between unmineralized and mineralized FC, local mechanical properties were surprisingly uniform inside enthesis FC while a modulation in stiffness, independent from mineral content, was observed in periosteal FC. We interpreted these different structure-property relationships as a demonstration of the high versatility of FC, providing high strength at the insertion (to resist tensile loading) and a gradual compliance at the periosteal surface (to resist contact stresses). STATEMENT OF SIGNIFICANCE: Mineralized fibrocartilage (FC) at entheses facilitates the integration of tendon in bone, two strongly dissimilar tissues. We focus on the structure-function relationships of two types of mineralized FC, enthesis and periosteal, which have clearly distinct mechanical demands. By investigating them with multiple high-resolution methods in a correlative manner, we demonstrate differences in fiber architecture and mechanical properties between the two tissues, indicative of their mechanical roles. Our results are relevant both from a medical viewpoint, targeting a clinically relevant location, as well as from a material science perspective, identifying FC as high-performance versatile composite.

Photodegradation of dyes using electrospun polymeric membranes containing titanium oxide and iron

This study aimed to analyze the photocatalytic degradation of Reactive Red 195, a textile dye belonging to the class of azo dyes. For this, a polymer membrane of Ecovio® (polymeric blend formed by PBAT/PLA) was obtained by the electrospinning technique, with the incorporation of semiconductors titanium dioxide (TiO2-R) and magnetite iron oxide (Fe3O4-M). The hydrophobic nature of the membrane required the treatment with sodium hydroxide (NaOH), in this way, the membranes were characterized with and without the semiconductors, as well as, with or without the alkali treatment. The techniques used for characterization were: contact angle analysis, infrared spectroscopy with Fourier transform (FT-IR), thermogravimetrics (TGA), X-ray diffraction (XRD), and differential exploratory calorimetry (DSC). The contact angle analysis of the membrane surface showed that it was hydrophobic before treatment with NaOH, with an average contact angle of 121.45 ± 1.44° and consequently low humidity. After treatment, there was a change in the surface with a change of the average contact angle value to 80.68 ± 1.52° and an increase in wetness. The FT-IR spectroscopy identified bands characteristic of the Ecovio® functional groups in the polymer blend, and discreet changes occurring after alkaline treatment. The TGA analysis showed that the incorporation of two semiconductors and the alkaline treatment resulted in a decrease in thermal stability for both the PLA polymer and the PBAT due to the possible interaction of the TiO2-R and Fe3O4-M semi-conductors with the polymers that we can promote a lower arrangement of fibers. The DSC analysis indicated possible changes in the polymer's structure due to the presence of semiconductors and alkaline treatment. A decrease in melting calories of the treated membranes compared to the untreated membrane indicates possible hydrolysis of the polymers. In the DRX analysis, an increase in the intensity of the peaks of the polymer membrane containing the semiconductors and subjected to alkaline treatment was observed. However, comparing membranes containing the semiconductors with pure membranes (without the semiconductors) subjected or not to alkaline treatment, possibly an alteration in crystallinity had a greater relationship with the incorporation of the two semiconductors in the pure membrane subjected to alkaline treatment continued to have predominantly amorphic characteristics. After obtaining and characterizing the membrane, studies were conducted to evaluate its potential in the photodegradation of the Reactive Red 195, using an Ecovio® polymer membrane incorporated with TiO2-R and Fe3O4-M, and treated with an alkaline solution. The results showed degradation above 80% after 24 h, in addition, the potential for reuse of this membrane was analyzed in 4 cycles of photocatalytic degradation, which showed that in all the cycles using the same membrane, the degradation remained above 80%, but at the end of the fourth cycle, a membrane still intact but visually more fragile was noted. Kinetic studies have shown that degradation follows the pseudo-first-order kinetic model. After the degradation cycles, the Fourier transform infrared spectroscopy (FT-IR) showed no new bands. Thus, the polymer membrane proved promising for the photodegradation of Reactive Red 195 given its efficiency, ease of separation from the reaction medium, and the possibility of reuse for several cycles.

Exploring the effects of thermal aging on scratch resistance of carbon fiber reinforced composite materials: A comprehensive study

AbstractThis paper investigates the scratch behavior of carbon fiber reinforced composites (CFRCs) under thermal aging conditions. Scratch depth was analyzed with respect to three parameters: velocity, thermal cycle, and direction of the scratch. The results showed that thermal aging has a significant effect on the scratch behavior of CFRCs, with an increase in thermal cycle leading to an increase in scratch depth. The scratch depth was also found to be greater in the weft direction compared to the warp direction, which can be attributed to the difference in fiber arrangement and orientation in the CFRC material. The analysis of variance (ANOVA) was performed to investigate the effect of thermal aging on the scratch behavior of CFRCs. The ANOVA results revealed that the direction of the scratch has a significant effect on scratch depth, with the weft direction showing greater scratch depth compared to the warp direction. The surface roughness of CFRCs was analyzed under thermal aging conditions and with an increase in thermal cycle leading to an increase in surface roughness. The roughness values were found to be higher in the weft direction compared to the warp direction, which can be attributed to the difference in fiber arrangement and orientation in the CFRC material.

Mechanical Properties of Uncured Thermoset Tow Prepreg: Experiment and Finite Element Analysis

This paper presents an experimental analysis of the tensile behavior of unidirectional carbon/epoxy prepreg, focusing on the nonlinearity observed at the beginning of the stress–strain curve. Due to the material’s high viscosity, securely holding specimens during testing was challenging, prompting modifications in the gripping method to ensure reliable data. By using a longer gauge length, the slippage impact on elastic modulus measurement was minimized, resulting in good repeatability among the test samples. Experimental findings highlighted the significant interaction between fiber waviness and the viscous matrix, leading to stiffness reduction. The linear stiffness of the samples closely matched that of the fibers and remained unaffected by temperature variations. However, at higher temperatures, the epoxy matrix’s decreased viscosity caused an upward shift in the stiffness plot within the non-linear region. To support the experimental findings, a micromechanical model of prepreg tow with fiber waviness was proposed. An RVE model of periodically distributed unidirectional waved cylindrical fibers embedded within the matrix was developed to predict effective material stiffness parameters. The simulation outcomes aligned well with the uniaxial tensile test of the prepreg tow, demonstrating the proposed RVE model’s capability to accurately predict elastic properties, considering factors like fiber arrangement, waviness, and temperature.

Magnetic field enhancing preferred orientation of nickel-cobalt plated carbon fibers in cement paste, with relevance to compression self-sensing

The arrangement of carbon fibers in the cement matrix affects the stability and sensitivity of the composite. This study investigated the effects of bath pH and electroless plating time on the magnetic metallization (nickel coating, cobalt coating, and nickel-cobalt alloy coating) on carbon fibers and successfully prepared the CFRCs in which the metal-plated carbon fibers could be oriented by magnetic fields. The results showed that a pH of 10 and a plating time of 6 min were favorable for reaction kinetics, with the thickness gain, conductivity, and saturation magnetization of metal coatings all being the largest. The compressive strength of the prepared composites was increased by 26.5% by adding nickel-cobalt coated carbon fibers, which is attributed to the alignment of fibers refining pore structure. The resistivity of CFRCs with metal-plated carbon fibers is one order lower in magnitude than that with uncoated carbon fiber, due to that the alignment of fibers increases the conduction connectivity by decreasing the distance of fiber-fiber and the “quantum tunneling”. The cyclic compressive loading tests showed that the resistance changed reversibly with strain, such that the degree of reversibility is higher for CFRCs with pre-magnetic treatment than those without the treatment. The piezoresistivity (strain sensitivity) of CFRCs was stronger with magnetic field-induced orientation treatment, showing that the strain sensitivity increased by 114% after pre-magnetic treatment for CFRCs containing nickel-cobalt coating. This is attributed to that the well-aligned metal-plated carbon fibers form more conduction paths along the alignment direction, such that the resistivity along this direction is more sensitive to the compressive strain parallel to this direction.

Harnessing nanofiber alignment and pore size to promote stem cell self-renewal and differentiation

Stem cell therapy holds immense potential for regenerative medicine, but its applications are limited due to the loss of pluripotency during in vitro expansion. One promising approach to regulate stem cells is through nanotopographies, such as nanofibers. This study reveals that the arrangement of electrospun fibers aligns with the distribution and strength of the electric field through both experimentation and simulation. An electrospinning collector is thus designed to produce nanofibrous membranes with defined alignment and pore size. The cell study shows that randomly oriented nanofibers with small pores promote self-renewal and adipogenic and osteogenic differentiation of human mesenchymal stem cells. Conversely, aligned mesh membrane, particularly those with medium pores, decreases cell proliferation, stemness, and differentiation potential by elongating the cells. Furthermore, our study suggests that stem cell behavior is sensitive to the nanofiber structure, which offers a potential direction in promoting stem cell expansion efficacy.