Increasing Fiber Content Research Articles

Characterization of Physical and Mechanical Properties of Rice Straw Particles and Furcraea foetida Fiber Reinforced Hybrid Composite

ABSTRACT The biodegradable characteristics and abundant availability of the fiber sources have gained the attention of various industries to produce natural fiber-based composites. As a sustainable alternative to the non-biodegradable fiber-based products, the natural composites provide a viable solution to reduce the environmental pollution caused by synthetic materials. This study developed rice straw particle (RSp) and Furcraea foetida (FF) fiber reinforced hybrid composite and investigated its physical and mechanical properties. The addition of 15 wt.% of RSp reduced the density of the test samples by 41.87% and its water absorption (WA) increased with the increase in fiber concentration. The composite with 5 wt.% and 15 wt.% of RSp showed maximum tensile strength (σt: 29.45 MPa) and modulus (σtm: 3.67 GPa), respectively. At 15 wt.% of RSp, the maximum flexural strength (σf: 43.12 MPa) and modulus (σfm: 2.09 GPa) was achieved and at 10 wt.% of RSp showed the highest impact strength (σi: 101.01 J/m). The σt (40.21%) and σf (7.76%) of the RSp reinforced composite were improved by the hybridization of FF (20 wt.%) fiber reinforcement.

Research on high-temperature rheological performance of fiber reinforced high-viscosity asphalt mastics

High-temperature performance of high-viscosity asphalt mastic containing fiber additive were studied by means of rheological analysis. The effects of two types of asphalt, two types of fillers, and two types of fibers with three fiber contents on the high-temperature rheological properties of asphalt mastic were evaluated by temperature sweep test, multiple stress creep recovery test, and frequency sweep test using a dynamic shear rheometer. The master curve of fiber reinforced high-viscosity asphalt mastic and phase angle were constructed using 2S2P1D model. The results show that the nature of asphalt plays a leading role in improving the resistance to deformation of asphalt mastic at high temperature, compared with the type of mineral powder. For the short-term aging asphalt mastic, with temperature increasing, the unrecoverable creep compliance gradually increases and the differences between asphalt mastic with different fiber contents also become greater. The creep recovery rate of mastic with basalt fiber is much higher than that of polyester fiber under the same conditions. For long-term aging asphalt mastic, compared with increasing fiber content, the fiber type has more significant influence on the storage modulus. 2S2P1D model can well fit the master curve of the complex modulus of fiber reinforced high-viscosity asphalt mastic, but poorly fit with the phase angle. From master curves, it finds that the enhancement of the fiber to mastic is prominent in the low frequency which is corresponding to the extreme high-temperature condition.

Test research on flexural strength of soil-cement reinforced with carbon fibers

In order to verify the feasibility of using chopped carbon fibers to reinforce soil-cement, the orthogonal test and verification test of flexural strength had been carried out and the correctness and effectiveness of the test results had been clarified. The test results indicated that the addition of carbon fibers could make the flexural strength of soil-cement improved effectively and change the brittle failure of soil-cement into plastic failure. The flexural strength of carbon fiber soil-cement (CFSC) could reach 0.509 MPa, that was 31.5 % higher than that (0.387 MPa) of the plain soil-cement in the standard condition. All the first extreme flexural strength (e.g. the flexural strength), yield strength, second extreme flexural strength and residual strength increased first and then decreased with the increase of either fiber content or fiber length. Thus, excessive fiber content and fiber length were not better and the optimum values were existent with 0.6 % and 15 mm respectively under the test conditions agreed in this study. The change magnitude of the yield strength, second extreme flexural strength and residual strength was much greater than that of the first extreme flexural strength. So the strengthening effect of the carbon fibers on soil-cement was better for its toughness and ductility than for its flexural strength. The order of soil type corresponding with the flexural strength of CFSC from high to low was clay, silty clay, mucky silty clay, silt and fine sand. The flexural strength of CFSC increased linearly with the increase of cement content and the economical cement content was obtained as 15 %. The flexural strength of CFSC increased quickly between the 3 d and 14 d, slowly between the 14 d and 28 d and very slowly after 28 d, but still was increasing. The interaction mechanism between carbon fibers and soil-cement had been analyzed from a macro and a micro perspective respectively. The modified multivariate nonlinear regression model was proposed. The results and conclusions above could provide reference and basis for the application and popularization of CFSC in actual engineering.

Effect of Flax Cake and Lupine Flour Addition on the Physicochemical, Sensory Properties, and Composition of Wheat Bread

Bread is consumed by people all over the world. Its quality may be modified by the application of other raw materials or changes in production technology. The addition of flax cake (FC) and lupine flour (LF) was proposed as a modification of the nutritional value of wheat bread. Bread with non-fermented and fermented FC and LF was prepared, and its physicochemical, sensory properties and composition were compared to wheat bread. A higher than 5% addition of these components reduced the bread volume and increased their hardness, gumminess, and chewiness. To reduce the negative impact of these additives on the physical and sensory properties of bread, these raw materials were fermented by selected starter cultures. The addition of FC and LF fermented by Lactobacillus plantarum lowered the undesirable changes in the physicochemical properties of the bread. It also slightly increased the overall acceptability of the products. Propionic fermentation lowered sensory assessment rates considerably. The following changes in the composition of bread prepared with the addition of fermented by L. plantarum FC and LF were noted: increase in protein (by ~30%), ash (by ~100%), both soluble and insoluble fiber (by ~500%) content. The starch content was reduced by about 18–20%. The modifications increased the nutritional value of the obtained bread, preserving its physicochemical properties and sensory acceptability.

Chloride induced mechanical degradation of ultra-high performance fiber-reinforced concrete: Insights from corrosion evolution paths

Chloride-induced corrosion of ultra-high-performance fiber-reinforced concrete (UHPFRC) inevitably affects structural durability. However, the process of multi-fiber corrosion and mechanical deterioration still lacks sufficient understanding. This work aims to reveal the fiber corrosion degradation mechanism from a microscopic to macroscopic view, applying multiple analytical analyses of atomic absorption spectrometry, SEM-EDS, nano-indentation, polarization, and macroscopic mechanical testing. Results show that the flexural strength of specimens decreases significantly with the increase of corrosion degree, and a clear reduction of up to 47% is found at a high corrosion degree. Elastic modulus and nano-hardness of corroded samples vary in a wide range of 30–189 GPa and 0.16–6.41 GPa. With the increase in fiber content, two distinctive corrosion mechanisms are proposed. The corrosion path deteriorates from fiber edge to inner by the invasion of erosive solution through the matrix at low contents (<2 vol%). Considering impurities, greater interfacial defects and macro-cell potential differences at high contents (≥2 vol%), another corrosion path originates from the fiber inner outward to the matrix. Fiber corrosion damages the fiber’s structural integrity and induces matrix deterioration, the micromechanics of the matrix along the fiber edge 20 μm decreases at least 10% more than the concrete matrix. This work firstly sheds light on the mechanical deterioration of UHPFRC from the perspective of fiber corrosion paths considering different initiation scenarios.

The effect of a barley-based food product in alleviating knee osteoarthritis discomfort symptoms in Egyptian female patients

Background/aim Osteoarthritis is a common joint condition that causes cartilage to erode. There are numerous conventional treatments available, including nonsteroidal anti-inflammatory medicines and pharmaceuticals containing glucosamine; however, taking them can result in serious side effects. The aim of this study was to prepare barley-based food product enriched with ginger, curcumin, garlic powder, and onion powder and to evaluate the effect of consumption of the prepared macaroni for 2 months, in alleviating knee osteoarthritis discomfort symptoms in female patients complaining of grade 2–3 knee osteoarthritis. Patients and methods The present study enrolled 51 Egyptian middle age females patients with a mean age of 51±8.37 years, diagnosed with bilateral grade two to three knee osteoarthritis were recruited from the National Research Centre rheumatology and rehabilitation clinic. Anthropometric measurements and blood samples were collected after 8 weeks of daily barley based macaroni supplementation (75 grams raw). Serum levels of IL1β, IL4 and IL6 were measured using Elisa techniques, while Total Antioxidant Capacity, Malondialdehyde, and Glutathione S-transferase were measured by the colorimetric methods. Results Chemical composition analysis of the prepared barley-based macaroni demonstrated a decrease in total carbohydrate content and an increase in crude fiber, protein, and fat content compared with the control (semolina wheat-based macaroni); 100 grams of the prepared uncooked barley macaroni provided 342.46 Kcal. The reevaluation of the anthropometric parameters after 8 weeks of daily macaroni supplementation denoting improvement without statistical significance (P&gt;0.05), and the clinical characteristics of knee joint osteoarthritis (Lequesne Index, WOMAC score, and Timed Up and Go test) significantly improved which meant less pain and stiffness. The serum pro-inflammatory cytokines IL1β and IL6 declined significantly and the serum anti-inflammatory cytokine IL4 raised significantly (P≤0.05), besides, barley based macaroni supplementation significantly improved the antioxidant status, which was achieved through the rise of serum Total Antioxidant Capacity and the decline of Malondialdehyde and Glutathione S-transferase activity (P≤0.05). Conclusion Barley-based prepared macaroni enriched with curcumin and ginger must be considered in alleviating the severity of knee OA symptoms to aid patients in getting their life back to near normal.

Plant-Based Ice Cream: Processing, Composition and Meltdown Properties Analysis

Plant-based foods have become a popular option for consumers due to their positive impacts on health and resulting changes in lifestyle. To preserve the quality of non-dairy ice cream during distribution and consumption, it is essential to understand its proximate composition and meltdown properties. In this study, cashews, coconut, and bananas were used as raw materials. Cashew milk and coconut cream were prepared separately and mixed at different ratios to make non-dairy ice cream. The proximate composition of the formulated ice cream was measured using the official standard methods. The meltdown properties, including drip-through (%), height (mm), and temperature (°C) were also assessed. The results indicated significant differences (p &lt; 0.05) in the proximate components of the produced ice creams. An increase (p &lt; 0.05) in protein, fibre, fat, and ash content was observed, as the amount of coconut cream increased, while the moisture content decreased, and the carbohydrate content remained unchanged. Furthermore, the meltdown properties of the ice cream changed significantly (p &lt; 0.05) as the amount of coconut cream increased. The quantitative data on proximate composition and meltdown properties presented in this paper are valuable for maintaining ice cream quality and consumer convenience in the frozen food business. They also provide deeper insight into non-dairy desserts.&#x0D; Keywords: Plant-Based Food; Ice Cream; Proximate Composition; Meltdown Properties

A Study of the Compressive Behavior of Recycled Rubber Concrete Reinforced with Hybrid Fibers

With the development of the automotive industry, a large amount of waste rubber is produced every year. The application and development of recycled rubber concrete (RRC) can effectively reduce ‘black pollution’ caused by waste rubber. However, the addition of recycled rubber particles can lead to a decrease in the compressive behavior of concrete. Previous research has demonstrated that by preventing crack growth, fiber addition can increase the strength and ductility of concrete. In this work, a total of 28 RRC mixes are designed, and the compressive behavior of RRC reinforced by steel fibers (SFs) and glass fibers (GFs) is investigated. The workability of fresh RRC can be negatively impacted by an increase in both fiber contents, with the GF content having a more notable effect. With the addition of fibers, the maximum increase rates for the compressive strength, elastic modulus, strain at peak stress, and compressive toughness were 27%, 8%, 45%, and 152%, respectively. A constitutive model is concurrently put forward to forecast the stress–strain curves of RRC with various fiber contents. These findings indicate that the maximum improvement in compressive behavior is achieved when the GF content was 0.4% and the SF content was 1.2%. The proposed constitutive model can be used to predict the stress–strain curve of hybrid fiber-reinforced recycled rubber concrete (HFRRRC).

A Cellulose Aerogel Made from Paper and Hemp Waste Added with Starch for the Sorption of Oil

One sustainable method of removing oil spills is the use of sorbents. In this study, aerogels made from paper waste and crosslinking starch are investigated as sorbents. Aerogels have a high porosity and, thus, achieve a high sorption capacity. The paper waste aerogels are compared with aerogel samples that also contain hemp fibres as a composite. After hydrophobisation with methyltrimethoxysilane, the maximum sorption capacity of crude oil, marine diesel oil and lubricating oil is investigated. Aerogels made of cellulose from paper waste with starch show the highest sorption capacity of about 50 gg−1 for all studied oils. Unfortunately, hemp fibres offer no advantage in sorption capacity, but they do mitigate a decrease in sorption capacity with an increase in cellulose fibre content. This could be an advantage in a possible commercial product, so that the properties do not vary as much.

Engineered cementitious composites using powder regenerated from municipal solid waste incineration bottom ash as supplementary cementitious material

Ecotype Engineered Cementitious Composites (ECC) can not only consume a huge amount of solid waste, reduce environmental pollution and human damage, but also reduce the high production cost of such materials. In this research, municipal solid waste incineration (MSWI) bottom ash was used to develop economical and applicable ecotype ECC. Firstly, the physical and chemical properties of MSWI bottom ash with different particle sizes were analyzed, and the bottom ash particles with high reactivity were screened out and ground into powder. Then the uniaxial tensile and four-point bending tests were used to study the mechanical strength and strain-hardening properties of ECC containing bottom ash powder. The results present that the powder milled by bottom ash particles with the size of 2.36–9.5 mm has finer particles and higher reactivity. The optimal ratio of bottom ash powder to cement for ECC can be determined as 2.2:1. Here ECC not only has high mechanical strength but also exhibits wonderful strain-hardening properties and multiple micro-cracking capacities. The increase in fiber content and water-binder ratio is beneficial to the development of excellent ductility. This study provides a strategy to produce low-cost ecotype ECC by using MSWI bottom ash powder as supplementary cementitious materials.

Antidiabetic, antihypertensive and antioxidant activity of cookies formulated with ground Mangifera indica L. leaves

SummaryThe objective of this study was to evaluate the antioxidant and inhibitory activity of ACE, α‐amylase and α‐glucosidase as well as their nutritional and physicochemical quality of cookies formulated with ground Mangifera indica L. leaves. Overall, the cookies formulated with 15 (CGML‐15) and 10% (CGML‐10) ground mango leaf exhibited higher content of crude fibre (5.50 and 3.06 g 100 g−1). DPPH, ABTS and FRAP results in cookies ranged from 18.72 to 5.18 mg TEAC 100 g−1, 21.59 to 7.89 mg TEAC 100 g–1 and 22.56 to 8.59 mg TEAC 100 g−1, respectively. The CMGL‐15 cookie presented the highest inhibitory activity of α‐glucosidase enzymes. Results confirmed the functionality of cookies CGML‐15 y CGML‐10 due to their increased fibre content and biological activity.

Mesoscale FE analysis of thermal conductivity of steel fiber-reinforced cementitious materials considering fiber-matrix interface and pore effects

The thermal conductivity (λ-value) of cementitious materials with steel fibers is not always better than that of plain cementitious materials due to the interface between the steel fiber and cementitious materials and the increased porosity. A mesoscale finite element (FE) model considering both fiber-matrix interface and pore effects was developed to quantify the influences of porosity, pore water saturation degree, fiber-matrix interface property, fiber content, fiber length, fiber shape, and fiber orientation on the λ-value of cementitious materials, which can explain well the various relationships between the λ-value of cementitious materials and steel fiber content reported in the literature. In the FE model, cementitious materials containing steel fibers were divided into two scales where Scale I included solid phase and pore, and Scale II was made up of the homogenous composites from Scale I and steel fibers. To achieve a more accurate representation of the pore structures, the pores at Scale I were created randomly without specifying their geometry. The fiber-matrix interface in cementitious materials at Scale II was modelled as a zero-thickness interface with constant interfacial thermal conductance. It is found that the λ-value of cementitious materials decreases linearly with increasing porosity but increases linearly with increasing pore water saturation degree. The influence of steel fiber on the λ-value of cementitious materials depends on the fiber-matrix interface property. When the fiber content or fiber length increases, the λ-value will increase for good fiber-matrix interfaces with high interfacial thermal conductance; while poor interfaces with low interfacial thermal conductance lead to an opposite trend. Fiber geometry has a limited impact on the λ-value. The fiber orientation can affect the λ-value of cementitious materials. When the fiber rotational angle with respect to the direction of temperature gradient increases, the λ-value of cementitious materials with the same fiber-matrix interface property will decrease.

Compressive Strength Dependency on the Effect of Temperature Variation on the Percentages of Steel Fiber in Concrete

Aims: The aim of this study is to check the effectiveness of steel fiber on the compressive strength of concrete. Background: Fibers have long been used as building materials to improve the ductility, tensile, compressive, and flexural strengths of concrete. Although fibers have been known as an effective reinforcement material for concrete structures, it is also acknowledged to be a suitable alternative to reinforcement steel bars. Objective: The objective of this research is to investigate some engineering properties, the compressive behavior of steel fiber reinforced concrete (SFRC), and the effect of elevated temperatures of up to 1000°C on concrete. Methods: Various tests which included the slump test, compressive strength test, as well as heating tests were done. The workability (slump) and thermal effects of M20 SFRC were evaluated. Results: Based on the results obtained, it could be observed that the workability of the M20 concrete reduced with the increase in steel fiber (SF) content from 0% to 1.6% as values obtained were 80mm, 73mm, 67mm, 61mm and 55mm for SF contents of 0%, 0.4%, 0.8%, 1.2%, and 1.6% respectively. These values showed medium workability of the concrete according to ASTM C-143/C-143 M-03. Also, the addition of SF to plain M20 concrete greatly improved the compressive strength (ƒc) with the concrete strength at 26.89N/mm2, 30.41N/mm2, 32.85N/mm2, 35.90N/mm2 and 39.66N/mm2 after 28 days of curing for steel fiber contents of 0%, 0.4%, 0.8%, 1.2%, and 1.6% respectively. The f_c after heating the concrete mix to 1,000°C showed improved thermal resistance with 4.2N/mm2, 8.23N/mm2, 11.63N/mm2, 15.60N/mm2 and 17.20N/mm2 for SF contents of 0%, 0.4%, 0.8%, 1.2% and 1.6% respectively. Conclusion: The incorporation of steel fibers in the concrete mix decreased the workability of SFRC but increased its compressive strength and balling tendencies.

DEVELOPMENT, STANDARDIZATION, PHYSICO-CHEMICAL AND NUTRITIONAL ANALYSIS OF BISCUITS DEVELOPED WITH DIFFERENT REPLACEMENT LEVELS OF PUMPKIN FLESH POWDER

Present study was planned and conducted at Institute of Food Science and Nutrition, University of Sargodha and Food Technology Section, AARI Faisalabad during 2020, to develop and analyze pumpkin flesh powder (PFP) and to prepare, standardize and evaluate biscuits with 0, 5, 10 and 15% replacement levels of PFP. Full ripened pumpkins were sliced, dried and grinded to obtain PFP. Straight grade flour (SGF) and PFP were analyzed for physico-chemical properties. PFP exhibited greater (6.15 ± 0.08) a* (redness) and (36.94 ± 0.19) b* (yellowness) values, significantly higher contents of moisture (14.29 ± 0.05%), ash (1.36 ± 0.03%), fat (1.24 ± 0.03%) and fiber (1.82 ± 0.01%), as compared to SGF. Upon analysis of physical characteristics of developed biscuits, as replacement level of PFP was increased to 15%, with SGF to develop biscuits, a* and b* values of biscuits were significantly increased to 5.06 ± 0.079 and 28.01 ± 0.14 respectively, thickness was also significantly increased to 48.50 ± 0.75 mm, while width was significantly decreased. Chemical analysis of biscuits revealed a significant increase in ash, fat fiber, Na, K and Fe contents of biscuits with increasing level of replacement of PFP. Whereas, non-significant results for moisture and protein contents were found. The contents of Ca, Mg and P were significantly decreased in added PFP biscuits. Sensory evaluation of biscuits proved that 5 to 10% replacement level of PFP got good scores close to the control so up to 10% replacement level of PFP with SGF was acceptable to develop good quality, nutritional biscuits. By keeping in view, the nutritional profile of pumpkin an effort was made to highlight the nutritional significance of pumpkin, pumpkin powder and biscuits developed with addition of pumpkin powder.

Experimental Study of Glass Fiber Reinforced Concrete Incorporating Micro Silica

The most common building material utilized worldwide is concrete. Concrete with higher compressive strength is becoming more and more in demand as the trend toward using it more widely for high rise buildings. Experimental study of glass fiber (GF) reinforced concrete incorporating micro silica was investigated in this study. The concrete is prepared by using M40 mix. GF with 12 mm length with aspect ratio of 857 is used. Four volume fractions of 0%, 0.4%, 0.8% and 1.2% by weight of cement and micro silica with 5% by weight of cement are used. The fiber is distributed randomly in all directions. The mixes were cast and tested for workability, compressive strength, flexural strength, water permeability test, drop weight Impact test, bond strength test and residual compressive strength at elevated temperature. Micro structural study is done with SEM analysis. Workability of glass fiber reinforced concrete decreased with increase in GF. Compressive strength show 12% increment whereas Flexure strength is increases 35% compare to normal concrete. Different percentages of glass fibres and micro silica have lower water penetration depths. With regard to the fire resistance test the compressive strength at elevated temperature decreases significantly. Impact resistance and bond strength of glass fiber reinforced concrete with micro silica increases with increase in fiber content. Hence, it's suggested to use glass fiber in the concrete according to use of concrete.

Experimental study on mechanical properties of material extrusion additive manufactured parts from recycled glass fibre-reinforced polypropylene composite

This paper presents an optimised material extrusion (MEX) 3D printing method with feedstock produced from glass fibre reinforced polypropylene (GFRPP) composite waste and investigates the effect of glass fibre weight fraction (0%, 15%, 30%, 40%) on the printability and mechanical properties of filaments and printed specimens. GFRPP feedstock filaments were fabricated by optimising the filament extrusion process parameters. The highest ultimate tensile strength (112 MPa) was obtained in a filament with 40% fibre weight content. In addition, repeated recycling of filament was shown to reduce the fibre aspect ratio and enhance the filament quality. It was shown that the increase in glass fibre content from 0% to 40% improved the ultimate tensile strength of MEX 3D printed specimens from 14.7 MPa to 23.4 MPa as well as the flexural strength of MEX 3D printed samples from 11.68 MPa to 66.55 MPa. The increase in fibre weight content from 30% to 40% had a minimal effect (+1%) on the ultimate tensile strength of the printed samples. In addition, the 40% filaments exhibited a more brittle behaviour, rendering them less suitable for MEX 3D printing than 30% GFRPP. The results showed that waste industrial GFRPP material can be effectively enhanced and converted to short fibre reinforced material extrusion filament feedstock for the printing of components as a circular economy demonstrator.

The tensile mechanical properties and constitutive model of plain ice and fiber-reinforced ice for construction

Ice and snow structure is a novel type of structure, which attracts more and more attention. As a novel green building material, the research of plain ice and fiber-reinforced ice material is the basis of ice and snow structures. This study aims to investigate the tensile mechanical properties and stress–strain constitutive relationship of plain ice and pulp fiber-reinforced ice (PFRI) by direct tensile tests. The experimental variables studied included the fiber contents (0%, 1%, 2%, 4% and 6%) and temperatures (-20 °C, −15 °C, −10 °C and −5°C). The results showed that the plain ice was more brittle under tension, while the PFRI material had the failure progress of crack generation, crack propagation and fracture, showing quasi-brittle characteristics. The peak strength, peak tensile strain and elastic modulus increased with the decreasing temperature. With the increase of fiber content, the peak strength and peak strain increased, while the elastic modulus decreased. Based on the experimental results, the prediction models of peak strength, peak strain and elastic modulus with respect to temperature and fiber content were established. As for plain ice, due to the strong brittleness, the direct tensile strength was basically the same as the splitting tensile strength. The direct tensile strength of PFRI was about 1.28 times the splitting tensile strength, and the direct tensile strength can better reflect the tensile properties. A segmented empirical constitutive model based on experiments and a damage constitutive model based on continuous damage theory were established. The damage constitutive model was embedded in ABAQUS by user defined material subroutine (UMAT) for finite element analysis, and the energy regularization of crack bond model was used to ensure the mesh size independence of the results. It showed that the proposed constitutive models can effectively predict the stress–strain behavior and failure characteristics of ice materials. This study will provide an important basis for the design and construction of ice and snow structures.

Effect of process parameters on the mechanical properties of fiber‐reinforced thermoplastics fabricated by direct fiber feeding injection molding

AbstractGlass fiber‐reinforced polypropylene composites (GF/PP) were fabricated in this study by direct fiber feeding injection molding technology (DFFIM) equipped with specially designed plasticizing units. By analyzing the fiber length distribution, scanning electron microscopy micrographs, and the mechanical properties of GF/PP composites, the effect of three process parameters, namely the number of fiber bundles, screw rotational speed, and injection pressure, on the properties of GF/PP composites fabricated by DFFIM were investigated. The results show that the mechanical properties of GF/PP composites gradually increase as the fiber content increases and the screw rotational speed decreases; however, when the fiber content exceeds a certain range, the enhancement effect of mechanical property is reduced due to the increase of fiber breakage and fiber aggregation. Appropriately increasing the injection pressure can increase the fiber length and make the fiber and PP more tightly bonded, and the mechanical properties of GF/PP composites gradually improve, but the fiber breakage phenomenon is more severe under excessive injection pressure, the mechanical property enhancement effect is reduced or even the mechanical property is decreased due to the decrease of the fiber length.

Toughening effect and mechanism of rice straw Fiber-reinforced lime soil

Lime-stabilized soil used for subgrade is prone to brittle damage under loading because of low toughness. Based on this phenomenon, the toughening effects of anticorrosive rice straw fibers on the lime-stabilized soil and its internal mechanism have been studied in this paper. Different fiber contents (0.2 wt%, 0.6 wt%, 1.0 wt%) and fiber lengths (0–10 mm, 10–20 mm, 20–30 mm) were studied. Three-point bending tests, unconfined compressive strength tests and triaxial compression tests were conducted on the rice straw fiber-reinforced lime soil. Energy absorption, deformation index, and brittleness index were evaluated under flexure, compression, and shear. The toughness change from energy, deformation, and strength was studied based on these. The toughening mechanism of fiber reinforcement was analyzed from the mechanism of fiber-soil interaction, the energy absorption threshold of the damage process, the damage pattern of specimens and the length of the crack propagation path. The results showed that with the increase in fiber content and fiber length, the energy absorption and deformation index of the damage process increased while the brittleness index decreased. The brittle damage pattern was improved, and the toughness increased. The fibers connect the soil particles on both sides of the fracture surface through the bridging effect, form a three-dimensional reinforcement network to restrict the soil particle movement and consume a lot of energy during the interaction with soil, which causes the increase in the energy absorption threshold of soil. Thus, the toughness of the lime-stabilized soil is improved.

Sorghum Flour Features Related to Dry Heat Treatment and Milling.

Heat treatment of sorghum kernels has the potential to improve their nutritional properties. The goal of this study was to assess the impact of dry heat treatment at two temperatures (121 and 140 °C) and grain fractionation, on the chemical and functional properties of red sorghum flour with three different particle sizes (small, medium, and large), for process optimization. The results showed that the treatment temperature had a positive effect on the water absorption capacity, as well as the fat, ash, moisture and carbohydrate content, whereas the opposite tendency was obtained for oil absorption capacity, swelling power, emulsion activity and protein and fiber content. Sorghum flour particle size had a positive impact on water absorption capacity, emulsion activity and protein, carbohydrate and fiber content, while oil absorption capacity, swelling power and fat, ash and moisture content were adversely affected. The optimization process showed that at the treatment temperature at 133 °C, an increase in fat, ash, fiber and carbohydrate content was experienced in the optimal fraction dimension of red sorghum grains. Moreover, the antioxidant performance showed that this fraction produced the best reducing capability when water was used as an extraction solvent. Starch digestibility revealed a 22.81% rise in resistant starch, while the thermal properties showed that gelatinization enthalpy was 1.90 times higher compared to the control sample. These findings may be helpful for researchers and the food industry in developing various functional foods or gluten-free bakery products.