Increasing Fiber Content Research Articles

Nutritional Value, Physical Properties, and Sensory Quality of Sugar-Free Cereal Bars Fortified with Grape and Apple Pomace

Cereal bars are so-called convenience foods. Consumers value these products as a healthier alternative to traditional chocolate bars. Since these snacks usually contain added dried fruit, they have high potential for the utilisation of waste materials from the fruit industry. The study aimed to determine the effect of fortification of cereal bars with grape and apple pomace on their nutritional value, physical properties, and sensory quality. The control recipe was modified by replacing 10 or 20 g of sultanas with apple or grape pomace. The fortification with these food by-products resulted in a significant increase in the moisture content of the products, an increase in soluble fibre content, and a decrease in the level of antioxidant compounds. The strength of the cereal bars supplemented with grape and apple pomace increased. In addition, the panellists noticed a colour difference compared to the unmodified product (2 < ΔE < 5). A positive effect of the addition of the fruit pomace on the visual characteristics of the cereal bars was also observed. No changes were observed in the tastiness of the product. On the other hand, the aroma of the modified products and the texture of the bars containing the apple residue were less acceptable. In conclusion, cereal bars containing grape pomace and up to 10 g of apple pomace are characterised by high soluble dietary fibre content and desirable sensory and mechanical properties and are therefore recommended for industrial production.

Effect of fiber type and content on mechanical properties of microbial solidified sand

Fibers are applied to construction works to improve the strength and brittle failure of the soil. In this paper, fibers with a length of 6 mm are added to the microbial cemented sand, and fiber types and content are research variable. Unconfined compressive strength (UCS), permeability coefficient, water absorption rate, dry density, and calcium carbonate precipitation of the solidified sand were tested. The physical and mechanical properties of fiber types and content on the immobilization of microorganisms were also analyzed from the micro–macro perspective. Results are presented as follows. The UCS of the Microbial induced calcium carbonate precipitation (MICP) treated sand increases first and then decreases with the increasing fiber content. This phenomenon is due to the promotion of calcium carbonate precipitation by short fiber reinforcement, the limited movement of the sand particles caused by the formed network between the fibers, and the enhanced strength of the microbial solidified sand. However, the agglomeration caused by additional fibers leads to the uneven distribution of calcium carbonate and the reduction in strength. The optimum fiber contents of polypropylene, glass, polyvinyl alcohol, and basalt fibers are 0.4%, 0.2%, 0.2%, and 0.1%, respectively.

Effect of germination on techno‐functional and nutraceutical properties of cowpea (Vigna unguiculata) flour

SummaryGermination is an economic and feasible process that have demonstrated changes in nutritional, biochemical and sensorial properties on cereals and legumes. The present work presents the impact of germination, at two different times (24 and 48 h) and temperatures (18 and 35 °C) on techno‐functional, nutraceuticals and nutritional properties of Vigna unguiculata (cowpea) flours. Germinated V. unguiculata (cowpea) flours showed a higher protein content (22.19%–23.30%) than ungerminated flour (20.72%), as well as an increase in ash and total dietary fibre content. In contrast, lipid content was reduced by half when germinated at 48 h and 35 °C. The values for phenolic compounds in germinated flours ranged from 10.22 to 21.94 mg GAE/g. The flavonoid content decreased between 10% and 31.5%. Antioxidant capacity increased after germination. Regarding techno‐functional properties, darker colour was obtained for germinated flours and more yellowness. For water absorption capacity, a range of 1.7–2.9 g/g were obtained, and an increase in oil absorption capacity was observed. Germination for 48 h and 35 °C resulted in a significant improvement of nutrient content and bioactive properties and showed good techno‐functional properties.

Effect of Pretreatments and Drying Methods on The Physicochemical and Antioxidant Properties of Whole Eggplant (Solanum aethiopicum) Flour

Sliced eggplant was pretreated (blanching and citric acid dip), -dried (oven and sun), then pulverized to flour. Physicochemical and antioxidant properties were evaluated using standard methods. The results showed increases in protein, moisture, fat, ash, crude fiber, and carbohydrate contents. They ranged from 7.78–8.39%, 8.90–10.14%, 4.32–5.28%, 0.77–0.91%, 10.72–13.43%, and 63.35–65.77%, respectively. Citric acid treatment and dried methods increased the minerals content for sodium (121.77–125.87 mg/100g), zinc (3.18–5.77 mg/100g), potassium (489.53–628.58 mg/100g), magnesium (68.86–75.39 mg/100g) and iron (8.91–11.82 mg/100g) than the blanched treatment. Functional properties of eggplant flour revealed that bulk density (0.42–0.50%,), oil absorption capacity (0.64–4.85%), and wettability (1.43–4.35%,) increased with citric acid and sun-drying method while swelling index (1.25–1.61%) and water absorption capacity (3.85–5.61%) increased with citric acid and oven drying method. Total polyphenol (26.49–29.78 mg GAE/mL), flavonoid (22.12–11.38 mg QE/mL), ABTS (52.38–61.34 Mmol/100 mL), DPPH (62.78–68.48%) and FRAP (58.67–65.36 Mmol/100mL) showed significant (p<0.05) increases in citric acid and dried methods. From the results, the physicochemical and antioxidant properties of eggplant flour were positively affected by citric acid pre-treatments in sun and oven-dried methods.

Chopped Areca Nut Fibers as Filler in Epoxy Matrix: Mechanical and Tribological Studies

In the current investigation, fibers extracted from the areca nut tree husk were either used unprocessed or processed with an alkaline treatment by being submerged in a 5 % sodium hydroxide solution. The average length of the areca fibers used in this work is 30 mm. Compression molding is used to create the composite out of an epoxy matrix with fibers added at 10, 15, 20 and 25 weight percent. The composites were tested for tensile strength, flexural modulus, Charpy impact, and shore D hardness, all of which showed the significant advantage acquired with quantity of fibers and fiber treatment. Pin on disc tribometer was used to conduct tribological tests on the treated fiber composites to analyse how the fiber-matrix bonding improved with an increase in fiber content. The primary shortcoming of the fibers is their relatively low elongation, which, even after treatment, hardly approaches 4 %. This indicates that the fibers are not uniform in length and prevents direct comparison to comparable composites containing a similar volume and length of natural fibers. The mechanical qualities of materials made with alkali treated chopped areca fibers where found to be enhanced when it was at 20 % volume fraction. A linear increment in values where observed in samples till 20 % volume fraction and a decrement with further increase in volume fraction. In the case of tribological evaluations, lesser values or wears were obtained at combination III for all the 3 loads, 10N, 15N and 20N. HIGHLIGHTS Three different amounts of fibers, namely 10, 15, 20 and 25 wt%, have been introduced in an epoxy matrix, fabricating the composite by compression molding. The composites were subjected to tensile, flexural, Charpy impact and Shore D hardness testing, which all demonstrated the considerable advantage obtained with quantity of fibers and fiber treatment, except in the case of hardness, where limited advantages were encountered. Also wear tests were carried out on treated fiber composites and surface morphology of the worn-out samples was studies, which demonstrated the improvement in fiber-matrix bonding obtained with the growing amounts of fibers. From the results on composites testing, it is evident that the areca nut husk fiber/epoxy polymer composites with an amount of short (30 mm length) random reinforcement introduced of 20 wt%, exhibits the highest peak mechanical properties among all the calculated properties. GRAPHICAL ABSTRACT

The early-age shrinkage cracking and late-age fracture properties of fiber-reinforced cementitious composites

In this research, the shrinkage cracking and fracture properties of fiber-reinforced cementitious composites (FRCC) are investigated using eccentric ring test and three-point bending test. In the eccentric ring test, the concept of the equivalent crack width (weq) is proposed based on the morphology and number of cracks of FRCC. A function considering curing time and fiber volume fraction is established to calculate the equivalent crack width of FRCC. The initial and complete-through cracking times of FRCC were measured to explain the effect of the fibers. In the three-point bending test, the crack initiation in FRCC is determined based on the average transverse force. The initial and unstable fracture toughnesses, as well as the fracture energy, have been calculated. The experimental results indicate that an increase in polyvinyl alcohol (PVA) fiber content can reduce the crack width and prolong the initial and complete-through cracking times induced by shrinkage. The unstable fracture toughness and fracture energy increase with the increase in the PVA fiber content. The results of the eccentric ring test and three-point bending test demonstrate that the primary role of PVA fibers is to extend the intermediate stage of cementitious materials from initial cracking to unstable cracking. Additionally, PVA fibers delay the energy release rate during the failure process.

Experimental study on time-dependent rheological properties and mechanical performance of cemented fine tailings backfill mixed with polypropylene fiber.

By preparing fine tailings slurry with different mass concentration and fiber content, the rheological parameters of slurry with different fiber content and curing time were tested. In addition, the influence law of fiber content and curing time on compressive strength was analyzed through the prepared fine tailings backfill samples, and the microstructure characteristics of fine tailings backfill were further studied. The results show that when the fiber content is 0.2 ~ 1.2%, the yield stress and plastic viscosity of the slurry increase with the increase of fiber content, and the thixotropy of the slurry also shows the same change characteristics. The bridge effect of fiber makes it easier for forming network structure, which increase the slurry rheology. When the curing time ranges from 0h to 2.5h, the increasing of curing time leads to the increasing trend of rheological parameters, and also increases the thixotropy of slurry. However, the increase of rheological parameters will continuously decrease when the curing time exceeds 1h, indicating that the influence of curing time on yield stress and thixotropy will gradually weaken with the continuous extension of curing time. When the curing age increases from 3 to 56days, the compressive strength of the fine tailings backfill increases with the curing age, but the increasing range of compressive strength decreases gradually. When the fiber content ranges from 0.2 to 1.2%, the compressive strength of backfill increases first and then decreases with the increase of fiber content, and reaches the maximum value when the fiber content is 0.6%. The extension of curing time reduces the generation of large-scale pore structure, which promotes the formation of more compact microstructure of backfill.

Mechanical Behavior of Fiber-Reinforced Soils under Undrained Triaxial Loading Conditions

The design of fiber-reinforced soil structures, such as embankments and pavements, can be carried out using the results of unconsolidated, undrained triaxial compression tests conducted on specimens at their “as-compacted” water content and analyzed in terms of total stresses. The effects of soil and fiber type on the mechanical behavior of fiber-reinforced soils have not been methodically or adequately examined in the past under these conditions, and the effects of fiber length and content on the shear strength parameters of fiber-reinforced soils need further experimental documentation. Accordingly, five soils ranging from “excellent” to “poor” materials for use in earthwork structures were tested in the present study, in combination with five types of polypropylene fibers having lengths ranging from 9 to 50 mm. Unconsolidated undrained triaxial compression tests were conducted on specimens at their “as-compacted” water content, with fiber contents ranging from 0.5 to 2% by weight of dry soil. Fiber reinforcement reduces the stiffness and increases the deformability of the soil. The fiber-reinforced soils exhibit a more ductile behavior in comparison with the unreinforced soils. A Mohr–Coulomb type linear failure criterion satisfactorily describes the shear strength behavior of fiber-reinforced soils in total stress terms. The cohesion values of the fiber-reinforced soils range between 61 kPa and 301 kPa and increase up to seven times in comparison with the cohesion values of the unreinforced soils. The variations of the angle of internal friction of soils due to fiber reinforcement are generally limited to ±25%. The cohesion improvement due to fiber reinforcement is increased with increasing fiber content and fiber length up to 30 mm and is inversely proportional to the fine-grained fraction and the cohesion of the unreinforced soil.

Crack behavior of expanded polystyrene foam-ceramsite composite thermal insulation mortar

To compensate for the deficiencies of thermal insulation, fire and crack resistances of traditional thermal insulation mortars, this paper prepares expanded polystyrene foam (EPSF)-ceramsites composite thermal insulation mortar (ECTIM) with ceramsite and EPSF particles as insulation aggregates. The effects of fiber content (i.e., P = 0.3%, 0.6%, 0.9%), fiber length (i.e., l = 3 mm, 6 mm, 9 mm) and fiber types (i.e., polypropylene fiber (PF), steel fiber (SF), alkali resistant glass fiber (ARGF)) on crack resistance of the ECTIM were analyzed. The test results demonstrated that the incorporation of fibers could significantly improve crack resistance and delay the cracking of mortar. With the increase of fiber content P, the water loss rate and cracking index decreased to 43.70% and 79.17% of the specimen without fiber. As the fiber length l increased from 0 mm to 9 mm, the water loss rate and cracking index decreased by 41.50% and 77.08%, respectively. Comparatively, the PF could obviously improve the crack resistance of the ECTIM. Based on the experimental research, the microscopic stress mechanism of mortar cracking, as well as the early and late anti-cracking mechanism of the ECTIM were revealed. In addition, considering the effects of fiber content and fiber length, a comprehensive influence coefficient ϖ was introduced, and a formula for conveniently calculating the maximum crack width Wmax of the ECTIM was proposed. The predicted results agreed well with the test data. The thermal insulation mortar prepared in this study could considerably overcome the deficiencies of traditional organic and inorganic thermal insulation mortars, and had excellent thermal insulation, fire and crack resistances. The resource utilization of iron tailings and the introduction of ceramsite reduced the materials cost. The prepared thermal insulation mortar could be used for wall substrate, geothermal heat insulation layer, external wall, internal wall and roof insulation.

Investigation of the functionality of macromolecules in the rheological and baking properties of oat milling fractions

The aim of this work was to investigate the role of oat constituents in rheological (mixing and pasting) properties and baking performance. To accomplish this, oat milling fractions with different particle size and dietary fibre contents were produced and analysed. Our results showed that with increasing flour particle size, in addition to fibre components, the level of proteins and lipids increased as well, while the digestible carbohydrate content decreased. There were changes also within the fine composition of macro components such as proteins (based on SDS-PAGE), starch (amylose to amylopectin ratio) and β-glucans (molecular weight distribution). With increasing fibre content, dough matrices were characterised by higher water absorption, longer development time, and lower softening, while flour slurries formed more viscous gels. Regarding baking properties of oat milling fractions, it was found that higher fibre content resulted in better crumb structure, supported by images of cross-sections and texture profile analysis. In addition, higher amylose to amylopectin ratio might have contributed to the formation of less resilient crumb structure. Correlation analysis between baking performance and rheological properties showed that doughs with higher water content and lower softening degree, as well as slurries with higher viscosity values resulted in better crumb structure. In conclusion, high-fibre oat milling fractions were found suitable to produce breads with acceptable quality traits. Our work might also contribute to expand our knowledge about the functionality of oat constituents and to develop new, fibre-rich oat-based products supporting the consumption of more dietary fibre.

Correlation of Bread Staling and Starch Digestibility and Role of Carboxymethyl Cellulose

AbstractThis study aims to correlate bread staling with starch digestibility rate. The study also investigates the effects of the use of an anti‐staling agent (carboxymethyl cellulose (CMC)) on starch digestion and glycemic index value. The results indicate that CMC utilization has an insignificant effect on a specific volume of bread, but, it decreases the crumb and crust lightness. CMC improves the textural properties of bread and reduces hardness during storage. The highest firmness increase is detected in the control sample, and the rate of firmness accelerates after the second day of storage. However, the addition of CMC leads to a decrease in the firmness of the bread. As expected, CMC is effective in slowing bread staling. The most novel results of the study are revealed through starch digestion. That storage period and CMC utilization affect significantly (p < 0.05) starch hydrolysis rate and staling has a decreasing effect on starch digestibility. After 4 days of storage, the expected glycemic index (eGI) decreases in all bread samples, and the highest decrease is observed in 5% CMC‐added bread samples. These results are also correlated with an increase in total dietary fiber content after the storage period.

3D Printing Technology for Short-continuous Carbon Fiber Synchronous Reinforced Thermoplastic Composites: A Comparison between Towpreg Extrusion and In Situ Impregnation Processes

Three-dimensional (3D) printing of carbon fiber-reinforced thermoplastic composites (CFRTPs) provides an effective method for manufacturing the CFRTPs parts with complex structures. To increase the mechanical performance of these parts, a 3D printing technology for short-continuous carbon fiber synchronous-reinforced thermoplastic composites (S/C-CFRTPs) has been proposed. However, the synchronous reinforcement that existed only at particular positions led to a limited improvement in the mechanical performance of the 3D-printed S/C-CFRTP part, which made it challenging to meet the engineering requirements. To solve this problem, two methods for achieving synchronous reinforcement at all the positions of the 3D-printed S/C-CFRTP part are proposed. To determine a suitable printing process for the S/C-CFRTP part, a comprehensive comparison between the two methods was conducted through theoretical analysis and experimental verification, involving the printing mechanism, fiber content, impregnation percentage, and mechanical performance. The results indicated that the towpreg extrusion process was suitable for manufacturing the 3D-printed S/C-CFRTP part. Compared with the in situ impregnation process, the towpreg extrusion process led to a fiber content increase of approximately 7% and void rate reduction of approximately 6%, resulting in 19% and 20% increases in the tensile and flexural strengths of the 3D-printed S/C-CFRTPs, respectively. Additionally, an optimized process parameter setting for fabricating an S/C-CFRTP prepreg filament with excellent mechanical performance was proposed. The findings of this study can provide a new approach for further improving the mechanical performance of the 3D-printed advanced composites.

The Properties of Modified Bagasse Fiber/Nano-TiO2 Composite Asphalt in a High-Temperature and High-Humidity Salt Environment.

The southern tropical coastal areas of China are high-temperature and high-humidity salt environments, which hinder the durability and service life of ordinary asphalt pavement. To enhance the durability of asphalt pavement in these areas, modified bagasse fiber combined with nano-TiO2 was used to improve the corrosion resistance of asphalt pavement in high-temperature and high-humidity salt environments. The micro-morphology, high-temperature oil absorption, high-temperature heat resistance, and hygroscopicity of bagasse fiber modified using three silane coupling agents combined with NaOH were compared, and the best silane coupling agent/NaOH modification scheme for bagasse fiber was found. Based on conventional physical tests (penetration, softening point, ductility), rheological property tests (rotational viscosity, dynamic shear rheological test, multi-stress creep recovery test, linear amplitude scanning test), and a four-point bending fatigue test of the asphalt mixture, the properties of modified bagasse fiber asphalt binder and mixture after cyclic dry-wet erosion under pure water and salt solution (NaCl, Na2SO4) were determined, and the effects of the erosion environment and fiber ratio on the basic physical and rheological properties of the asphalt were clarified. Compared with the silane coupling agents KH550 and KH590, the bagasse fiber modified with KH570/NaOH had a better high-temperature oil absorption capacity, heat stability capacity, and matrix asphalt compatibility. The worst erosion environment was Na2SO4, but the increase in test temperature and fiber content weakened the sensitivity of the asphalt binder performance in different erosion environments. The erosion capacity order was as follows: Na2SO4 > NaCl > pure water. In the worst erosion environment, 0.5% modified bagasse fiber/Nano-TiO2 asphalt binder (Bn-570-0.5) had the best corrosion resistance in a high-temperature and high-humidity salt environment. The penetration, softening point, creep recovery rate R3.2, non-recoverable creep compliance Jnr3.2, and fatigue life after long-term aging (with 5% strain) of Bn-570-0.5 were, respectively, increased by -16.9%, 37.5%, 37.95%, -27.86%, and 38.30% compared with unblended base asphalt binder (B). In addition, the four-point flexural fatigue life of Bn-570-0.5 was 169.2% higher than that of the unblended base mixture.

A quantitative investigation on the fragmentation performance of SCDA in cracking steel fiber reinforced concrete

A better application of Soundless Chemical Demolition Agents (SCDAs) in fragmentation is based on our knowledge on their expansive characteristics. In this study, an integration of experimental and modeling approaches was developed to investigate SCDA expansion and corresponding cracking processes of Steel Fiber Reinforced Concrete (SFRC). The expansive properties of the selected SCDA were first estimated by free volume expansion (FVE) tests and expansion pressure (EP) tests. Then, cracking experiments were performed on 150 mm cubic SFRC blocks with a predrilled hole, and the cracking process was monitored by using Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques. Generally, the cracking process can be divided into three phases, termed micro-cracking phase, macro-cracking phase, and failure phase. It was observed the hole diameter and fiber content exert significant influences on the cracking process. The crack initiation time was shortened as the hole diameter increases, while it was prolonged with increasing fiber content. The cracked area ratio was further proposed and measured to assess the cracking performance of SCDA. The ratio increases from 2.73% to 8.293% as the hole diameter increases from 16 mm to 26 mm, while it decays from 9.75% to 1.823% as the fiber content increases from 0 to 2.4%. After verified with the experimental data, a modified Concrete Damaged Plasticity (CDP) model was adopted to extend the fragmentation of SFRC from the centimeter scale to the meter scale. The simulations were conducted on SFRC models with various hole diameters, spacings, and fiber contents. The simulated results show the fragmentation performance is related to both hole parameters (e.g., hole diameter, spacing, etc.) and SFRC properties (including elastic modulus, fiber content, etc.). In particular, the cracked area (DamageT > 0.9) varies directly with hole spacing, diameter, and fiber content. Built on the simulated results, an empirical equation was formulated to quantitatively evaluate the fragmentation ability of individual holes. In addition, extra simulations were conducted to assess the efficiency of SCDA in cracking PC/SFRC beams of various sizes. The obtained cracked area tends to decrease first and then approach a constant value with increasing beam sizes, indicating the existence of a size effect, which is primarily due to variations in concrete restraints provided by beams of different sizes. This work quantitatively evaluates expansive properties of SCDA and SCDA-induced cracks, and thus provides a reference for optimizing the field application parameters.

Shear Strength Behaviors of Aeolian Sand Solidified by Microbially Induced Calcite Precipitation and Basalt Fiber Reinforcement.

Aeolian sand flow is identified as the main factor in the formation of sandstorms. However, conventional sand fixation methods cannot meet the current development requirements of environmental protection. In this paper, the method using Microbially Induced Calcite Precipitation (MICP) combined with basalt fiber reinforcement (BFR) was adopted to solidify the aeolian sand. Consolidated undrained triaxial shear tests were carried out to analyze the influence of fiber content, fiber length, confining pressure, and other factors on stress-strain characteristics, peak strength, brittleness index, and shear strength of aeolian sand. A shear strength model of aeolian sand solidification using MICP-BFR and considering the effect of fiber length and fiber content is established according to the test results. The results show that the peak strength of aeolian sand solidified by MICP-BFR is remarkably higher than that of aeolian sand solidified by MICP alone, and the peak strength rises with the increasing fiber length, fiber content, and confining pressure. The application of fiber can effectively reduce the brittleness index of aeolian sand solidified by MICP and improve the sample ductility. As fiber content and fiber length increase, the cohesion of solidified aeolian sand increases while the internal friction angle changes relatively little. In the limited range set by the test, the fiber length of 12 mm and the fiber content of 1.0% constitute the optimum reinforcement condition. The test results coincide with the model prediction results, indicating that the new model is fitting for predicting the shear strength of aeolian sand solidified by MICP-BFR. The research results provide an important reference value for guiding the practice of wind prevention and sand fixation in desert areas.

Recent progress in thermal and acoustic properties of natural fiber reinforced polymer composites: Preparation, characterization, and data analysis

AbstractNatural fiber reinforced polymer composites (NFRPCs) have emerged as promising eco‐friendly alternatives over conventional synthetic fiber composites due to their inherent biodegradability, renewability, low environmental impact, and lightweight properties. It has been seen a significant growth in both invention and innovation in the field of NFRPCs. Natural fibers (NFs) reduce the cost of the material by 5%, the weight of the composite by 10%, and the energy required for production by 80%. In terms of thermal, and acoustic properties, NFs can successfully compete with synthetic fibers. As a result, the development of NFRPCs for industrial use has increased significantly in the past decade to meet the growing demands of industrial sectors. To improve the thermal and acoustic properties of NFRPCs, researchers have done a lot of investigation. The aim of the current review is to provide a comprehensive analysis of the existing literature on the thermal and acoustic properties of natural fiber reinforced polymer composites. Thermal properties such as thermal conductivity, TGA, DSC, DMA, and acoustic properties of natural fiber reinforced composites with several parameters, such as different fiber types, different matrix types, fiber weight ratio, fiber to matrix ratio, chemical treatment of fiber have been summarized and analyzed very concisely. This review also emphasizes a summary of different natural fibers, their chemical compositions, composite preparation, characterizations, and future research directions. This article enables the readers, researchers, and manufacturers to realize several opportunities about the latest developments in NFRPCs for the application of thermal and acoustic purposes.Highlights Natural fibers can successfully compete with synthetic fibers, in terms of thermal and acoustic properties. Thermal properties of natural fiber reinforced composites including thermal conductivity, TGA, DSC, and DMA are summarized. Acoustic properties of natural fiber reinforced polymer composites are discussed. Composite materials made of treated fibers result better thermal stability than untreated fiber composites. Sound absorption coefficient generally increases as fiber content increases.

CONTRIBUTORY IMPACT OF SEWAGE ON POLLUTED OGUN AND LAGOS FISHING WATERS: INFLUENCE ON ANTIOXIDANT PROFILE AND PROXIMATE COMPOSITION OF SILVER CATFISH (Chrysichthys nigrodigitatus)

Water pollution, a recurring phenomenon in fishing waters of industrial cities in Nigeria, inadvertently constitute hazards to the host biotic communities and the ecosystem. To continuously delineate the impacts of pollution via sewage outlets on aquatic life, this rainy season study investigated Chrysichthys nigrodigitatus, an aquatic food from Ogun River and Epe Lagoon, Nigeria, both of which are locally channeled for sewage release. Sixty (60) samples of C. nigrodigitatus were collected from six sites each representing a group (n=10), with mean weight and length of 762.20 ± 11.05 g and 42.21 ± 0.30 cm respectively. Ajegunle (control), Alaapa and Quarry (test sites) along the Ogun River course in Abeokuta; Ebute-Alashe (control), Oluwo and Marina (test sites) along the Epe Lagoon. Analysis of Biochemical Oxygen Demand and Chemical Oxygen Demand showed elevated variations at the sampled test sites than the control sites and above WHO safe limits. Significant (p < 0.05) increases in concentrations of heavy metals (lead, arsenic and cadmium) in the fishing waters from the sampled test locations particularly the Quarry and Marina sites, as well as in blood samples of fish, were observed when compared with their respective controls. Antioxidants profiling showed significant increases (p < 0.05) in superoxide dismutase and catalase activities in fishes from Alaapa (14- and 3- folds), Quarry (8- and 4- folds), Oluwo (9- and 3- folds) and Marina (8- and 3- folds) sites, while significant increases in glutathione-S-transferase activity were observed only in fishes from Quarry (5- fold) and Marina (4- fold) sites respectively. The glutathione concentration significantly decreased in fishes from all the test sites while malondialdehyde concentrations significantly increased in fishes from all the test sites compared with the respective controls. Proximate analysis of the fish samples showed significant increases (p < 0.05) in moisture and fiber contents, but significant decrease in fat, ash and protein contents compared with the respective controls. The results of the study showed that sewage pollution of fishing waters is hazardous to aquatic life as it induces oxidative stress and significantly reduces the nutritional value of the fishes obtained from such water bodies.

Effect of ceramic fiber on mechanical properties of concrete with different strength grades and its strengthening and toughening behaviors under impact load

The mechanical properties of ceramic fiber reinforced concrete (CRFRC) with different strength grades (C30, C50 and C80) under impact load were studied, and the strengthening and toughening behaviors of ceramic fiber on plain concrete were analyzed and compared with that of carbon fiber. The results show that ceramic fiber can improve the mechanical properties of concrete with different strength grades under impact load, and the optimal content of ceramic fiber is 0.2%. Ceramic fiber has strengthening and toughening effect on concrete, and the strengthening and toughening behaviors of ceramic fiber are better than that of carbon fiber. Ceramic fiber has the best strengthening effect on C50 concrete and the best toughening effect on C80 concrete. The dynamic compressive strength (fcd), energy dissipation density (Edd) and dynamic increase factor (DIF) of CRFRC all have strain rate effect. As the ceramic fiber content increases, the strain rate sensitivities of fcd and Edd of CRFRC increase first and then decrease. As the strength grade increases, the strain rate sensitivities of fcd and Edd decrease. The strain rate effect of DIF of CRFRC has a transition strain rate. The transition strain rate of DIF of CRFRC decreases with strength grade and it decreases compared with plain concrete.

Determination of optimum blast furnace slag ash and hemp fiber ratio in cement mortars

This study aims to investigate the effect of incorporating hemp fibers into cement mortars to enhance their mechanical properties. Additionally, the study examines the use of blast furnace slag (YFC) as a substitute for cement to reduce costs. The findings demonstrate that adding 1%, 2%, and 4% hemp fibers to cement mortars yields the best results in terms of density, water absorption, compressive strength, bending strength, compressive strength after bending, and flexural strength. In conclusion, the study reveals that incorporating hemp fibers enhances the workability of YFC-blended mixtures while reducing the spreading diameter as the hemp fiber content increases. Additionally, an increase in YFC substitution leads to a decrease in compressive strength; however, the addition of 1% hemp fiber to the Y15 mixture results in a approximately 12% increase in compressive strength, indicating improved matrix strength and reduced crack formation. Moreover, the study shows that the flexural strength increases with the addition of hemp fibers, with the highest flexural strength observed in the mixture containing 4% hemp fiber and 10% YFC substitution. The results highlight that the combination of YFC and hemp fibers can produce strong, durable, and environmentally friendly composite materials. These materials offer a lower environmental impact and cost-effectiveness compared to traditional construction materials.

Circular Production, Designing, and Mechanical Testing of Polypropylene-Based Reinforced Composite Materials: Statistical Analysis for Potential Automotive and Nuclear Applications.

The circularity of polymer waste is an emerging field of research in Europe. In the present research, the thermal, surface, mechanical, and tribological properties of polypropylene (PP)-based composite produced by injection molding were studied. The pure PP matrix was reinforced with 10, 30, and 40% wt. of pure cotton, synthetic polyester, and polyethylene terephthalate post-consumer fibers using a combination of direct extrusion and injection molding techniques. Results indicate that PP-PCPESF-10% wt. exhibits the highest value of tensile strength (29 MPa). However, the values of tensile and flexural strain were lowered with an increase in fiber content due to the presence of micro-defects. Similarly, the values of modulus of elasticity, flexural modulus, flexural strength, and impact energy were enhanced due to an increase in the amount of fiber. The PP-PCCF-40% wt. shows the highest values of flexural constant (2780 MPa) and strength (57 MPa). Additionally, the increase in fiber loadings is directly proportional to the creation of micro-defects, surface roughness, abrasive wear, coefficient of friction, and erosive wear. The lowest average absolute arithmetic surface roughness value (Ra) of PP and PP-PCCF, 10% wt., were 0.19 µm and 0.28 µm. The lowest abrasive wear value of 3.09 × 10-6 mm3/Nm was found for pure PP. The erosive wear value (35 mm3/kg) of PP-PCCF 40% wt. composite material was 2 to 17 times higher than all other composite materials. Finally, the single-step analysis of variance predicts reasonable results in terms of the p-values of each composite material for commercial applications.