Evaluation of clogging effects on nonwoven geotextile filters by negative-ion treatment

Clogging effects on nonwoven geotextile filters can reduce the drainage capacity of vertical drainage materials installed in clay deposits. The preceding clogging retention improvement can be increased if the nonwoven geotextile filter is treated by negative ion material in accordance to the knowledge that fine soil particle is negatively charged material. In this study, column tests were conducted to examine the effects of negative-ion treatment by using various types of ion-treated nonwoven geotextile filters. It was found that the negative ion treatment gave apparent increase of drainage capacity after long time as describe on this paper. Clogging effects of two nonwoven geotextile filters treated by negative ion (10 %; NI-10 and 20 %; NI-20) were compared to non-ion treated one (control) by long term filtration test. Finally, the highest drainage capacity was obtained by NI-20 followed by NI-10.     

Mechanical and thermo-mechanical analysis based numerical simulation of granite powder filled polymer composites for wind turbine blade

In present article fabrication and characterization of unfilled and granite powder filled carbon epoxy composites are reported. Addition of carbon fiber shows positive effect on mechanical performance of the composites. However, incorporation of granite powder has negative hybridizing effect on the properties such as tensile strength, flexural strength and inter-laminar shear strength. The storage modulus evaluated at 30 °C is in close agreement with flexural modulus of composites. Further, successful attempt is made for numerical simulation of actual geometry of wind turbine blade. The results obtained from numerical analysis are comparable with experimental results.     

Relationship between chemical composition,crystallinity, orientation and tensile strength of kenaf fiber

The physical properties of natural growth fibers such as chemical composition content and fiber diameter are highly affected by environmental issues such as environmental changes and fiber extraction methods. These irregularities of the natural fibers seriously affect its utilization in composite as reinforcements. In this study, taking into account the importance of the fiber tensile strength, the correlation degrees between the kenaf fiber tensile strength and the fiber chemical composition, crystallinity, orientation degree were analyzed by the grey relational analysis method. Both the kenaf single fiber and fiber bundle were used as XRD and tensile strength test sample. The chemical composition content and the FTIR were carried out to obtain a correct result of the chemical composition content. It found that for the different XRD and tensile strength test samples, the single fiber showed lower crystallinity, higher orientation degree and tensile strength compared with the fiber bundle. The cellulose content and the orientation degree got the higher correlation degree with single fiber tensile strength, which was 0.674 and 0.640. The highest factor associated with the fiber bundle tensile strength was the orientation degree, the correlation degree was 0.747. The hemicellulose content and the crystallinity also got high correlation degree with the fiber bundle strength, which was 0.687 and 0.640.     

Tensile and bending behavior for woven carbon-aramid/epoxy hybrid composites with various lamination structures by the VARTM method

High-performance composites by super fiber are difficult to apply at industrial field due to the high cost. To overcome this problem, there is a need to widely spread the use of the excellent composites. The composites with superior mechanical performance were investigated by a suitable stacking combination under limited amounts of a raw material. Carbon/aramid hybrid composites were soundly manufactured using the VARTM process. The excellent combinations of both the tensile and bending properties were determined. The lamination position and the continuous cumulative count of reinforcements play an important role in the strength and stiffness.     

The roles of phellem (skin) tensile-related fractures and phellogen shear-related fractures in susceptibility to tuber-skinning injury and skin-set development

The susceptibility of potato tubers to excoriation (idiom = skinning injury) during harvest is a widespread problem that results in costly disease, defects, and shrinkage. Little is known about the physiology associated with susceptibility of immature periderm and the development of full and final resistance to skinning injury (skin-set) upon periderm maturation. The objective of this research was to determine the roles of phellem (skin) tensile and phellogen shear-related fractures in skinning injury and in the development of resistance to tuber-skinning injury upon skin-set. The resistance to skinning injury was measured on potato tubers with immature and mature periderm using genetically diverse cultivars during two growing seasons. Separate force measurements (mNm) were obtained to determine the relative strength associated with the “total resistance to skining” and the “phellogen shear component” (total resistance to skinning = phellem tensile component plus phellogen shear component). The relative strength of the “phellem tensile component” was calculated by subtracting the force measurement for the phellogen shear component from the total resistance to skinning. The results indicate that the phellem tensile component plays a minor role in the total resistance to skinning in immature and mature periderm. The relative strength of the phellem tensile component appeared to be nearly constant for all time points for each cultivar and did not measurably increase as the periderm approached maturation; this indicates that the phellem/skin tensile component does not contribute to skin-set development. However, the force required for fracture of the phellogen shear component did increase upon periderm maturation. These results indicate that the increased strength of the phellogen shear component was the determinant for the development of full resistance to skinning injury, i.e., skin-set. This research uncovers and defines the role of this second component, the phellem tensile component, for incorporation into the recently conceived paradigm for tuber excoriation and skin-set. These findings are consistent with and complement recent microscopical research which showed that the phellogen layer of immature periderm was the single tangential plane of fracture upon skinning and that this layer of cells was no longer prone to fracture upon development of full resistance to tuberskinning injury. The results were similar for all cultivars tested and provide a definite direction for future research on the biochemical changes and processes associated with phellogen cell wall strengthening, which comprises the phellogen shear strength component.     

Comparison of structural features of reconstituted doughs affected by starches from different cereals and other botanical sources

Starch, as the main component of flour products, determines the physicochemical properties of dough. This work investigated the relationship of the physical properties of seven types of starches from various cereals with the structural features of reconstituted dough. Results of mixing and tensile properties analysis and scanning electron microscopy displayed that rice reconstituted flour exhibited maximum water absorption; pea reconstituted flour had higher dough stability; sweet potato dough had higher tensile resistance; highland barley dough had the greatest extensibility. Moisture distribution analysis revealed that various model dough showed remarkably different water distribution, which was distributed at T₂₁ (0.07–0.11 ms), T₂₂ (0.8–2.66 ms) and T₂₃ (10.0–20.82 ms). Correlation analysis indicated that large starch granules associated with good dough stability; amylose content of starch positively affected tensile resistance of dough; crystallinity of starch showed negative effects on water absorption; starch with higher crystallinity associated with greater dough stability.     

Evaluation of mechanical properties of jute/glass/carbon fibers reinforced hybrid composites

A study on the tensile and flexural properties of jute-glass-carbon fibers reinforced epoxy hybrid composites in inter-ply configuration is presented in this paper. Test specimens were manufactured by hand lay-up process and their tensile and flexural properties were obtained. The effects of the hybridization, different fibers content and plies stacking sequence on the mechanical properties of the tested hybrid composites were investigated. Two-parameter Weibull distribution function was used to statistically analyze the experimental results. The failure probability graphs for the tested composites were drawn. These graphs are important tools for helping the designers to understand and choose the suitable material for the required design and development. Results showed that the hybridization process can potentially improve the tensile and flexural properties of jute reinforced composite. The flexural strength decreases when partial laminas from a carbon/epoxy laminate are replaced by glass/epoxy or jute/epoxy laminas. Also, it is realized that incorporating high strength fibers to the outer layers of the composite leads to higher flexural resistance, whilst the order of the layers doesn’t affect the tensile properties.     

Predicting the tensile strength of polyester/cotton blended woven fabrics using feed forward back propagation artificial neural networks

Tensile strength plays a vital role in determining the mechanical behavior of woven fabrics. In this study, two artificial neural networks have been designed to predict the warp and weft wise tensile strength of polyester cotton blended fabrics. Various process and material related parameters have been considered for selection of vital few input parameters that significantly affect fabric tensile strength. A total of 270 fabric samples are woven with varying constructions. Application of nonlinear modeling technique and appreciable volume of data sets for training, testing and validating both prediction models resulted in best fitting of data and minimization of prediction error. Sensitivity analysis has been carried out for both models to determine the contribution percentage of input parameters and evaluating the most impacting variable on fabric strength.     

A study of the mechanical properties of natural fibre reinforced composites

This paper presents the results of a current research of the tensile properties: ultimate strength and stiffness modulus in composites using natural reinforcements. Hemp short fibres and pine sawdust were randomly distributed in polypropylene matrices to produce composite plates with 5 mm thickness by injection moulding technique. The specimens were cut from these plates with bone dog shape or plane bars, and tested in tensile and four points bending, respectively. Stiffness modulus and ultimate stresses were obtained for different weight fraction content of reinforcement and discussed taking in account the failure modes. Four series of pine sawdust reinforced specimens were immersed in water in periods up to 20 days. Periodically, the specimens were removed from the water recipient and immediately tested. The damage effect of water immersion time was discussed based in the tensile results and in the water absorption curves.     

Scalable preparation of multiscale carbon nanotube/glass fiber reinforcements and their application in polymer composites

The introduction of carbon nanotubes (CNTs) into conventional fiber to construct a hierarchical structure in polymer composites has attracted great interest owing to their merits of performance improvement and multiple functionalities. However, there is a challenge for realizing the scalable preparation of the multi-scale CNT-glass fiber (CNTGF) reinforcements in practical application. In this work, we present a simple and continuous method of the mass production of multiscale CNT-glass fiber (CNT-GF) reinforcements. Scanning electron microscopy and thermo gravimetric analysis indicated ~1.0 wt% CNTs were highly dispersed on the whole fiber surface through a facile surfactant-assisted process. Such hybrid CNT-GF fillers were found to effectively enhance the stiffness, strength and impact resistance of polypropylene polymer. Increased storage modulus, glass transition temperature and crystallization temperature of the composites filled with the CNT-GF fillers were also observed in the differential scanning calorimetry and dynamic mechanical analysis compared with the composites containing the pristine GF fillers. Fracture surface analysis revealed enhanced interfacial quality between CNT-GF and matrix, which is likely responsible for improved performance of the hierarchical polymer composites.     

Properties of medium-density particleboard from saline Athel wood

The Athel tree, Tamarix aphylla (L), can potentially be used as a biomass crop to help manage saline subsurface drainage water in arid land irrigated agriculture. In this study, Athel wood was used to manufacture medium-density particleboard with an aim of developing new applications for the saline wood. The research investigated the effects of different types of adhesives, particle sizes, bark content (BC), resin content (RC), and hot water pretreatment on the mechanical and water resistance properties of the Athel-derived, medium-density particleboards. The measured mechanical properties included tensile strength (TS), modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IB) of the finished particleboards. Water absorption and thickness swell were used to evaluate the water resistance. Polymeric methane diphenyl diisocyanate (PMDI) resin made particleboard of better mechanical properties and water resistance than urea formaldehyde (UF). The medium size (20–40 mesh) particles gave the best mechanical properties and water resistance than of the particleboard when evaluated against the smaller size (40–60 mesh) and larger size (10–20 mesh) particles. The mechanical properties of particleboard were improved as the resin content of the UF-board increased from 7 to 16%, but deteriorated as the bark content increased from 0 to 16.2%. The particleboard made from the wood particles that had undergone hot water pretreatment had poor mechanical properties and water resistance compared with the particleboard made from the untreated particles. Saline Athel wood is an appropriate material for manufacturing particleboards.     

Modeling and differential evolution optimization of PAN carbon fiber production process

In this research, results of an experimental and artificial neural network fuzzy interface system (ANFIS) modeling of operating parameters on tensile strength of the carbon fibers are investigated. To do these experiments, the commercial polyacrylonitrile (PAN) fiber of Polyacryl Iran Corporation (PIC) was used as the precursors. The results show that increasing all of parameters improves tensile strength performance. ANFIS was applied to predict tensile strength of carbon fibers as a function of stabilization temperature at first stage (STFIS), stabilization temperature at second stage (STSS), stabilization temperature at third stage (STTS), stabilization temperature at fourth stage (STFOS), and carbonization temperature (CT). The optimum levels of influential factors, determined for tensile strength are STFIS 200 °C, STSS 225 °C, STTS 240 °C, STFOS 260 °C, CT, and 1400 °C. The modeling results showed that there is an excellent agreement between the experimental data and the predicted values. Furthermore, the fiber process is optimized applying differential evolution (DE) algorithm as an effective and robust optimization method.     

Systems analysis of wheat production on low water-holding soils in a Mediterranean-type environment: II. Drainage and nitrate leaching

In Mediterranean-type environments, the concentration of rainfall in winter months results in average winter rainfall that is in excess of evaporative demand. Cropping coarse textured soils in such regions results in a risk of drainage below the root zone, and associated with this, nutrient leaching. We used the APSIM-Nwheat simulation model to quantify the magnitude and variability of drainage and nitrate–N leaching under wheat crops for six locations and three soil types in the northern sandplain region of the Western Australian wheat belt and to assess the impact of varying crop management on drainage and leaching. Overall, the combination of a high concentration of rainfall in the winter months and coarse soil types resulted in a significant risk of drainage and leaching events of considerable magnitude even at the driest sites considered: the assumption that leaching and drainage are low in areas of low rainfall is an over-simplification. For some locations, simulated drainage was high, exceeding 100 mm for two locations on two soils; the sand and the acid loamy sand. Across the six locations considered, drainage was linearly related to average growing season rainfall. Leaching varied markedly between the soil types, with loamy sand having only one fifth the leaching that was calculated for the acid loamy sand or the sand. This emphasises the importance of small differences in soil type for the risk of drainage and leaching, and hence the potential for negative off-site effects, when cropping light soils in a Mediterranean-type environment. Although sandy soils are held to present the most scope for reducing drainage through agronomic management, the analysis suggested the potential improvements are likely to be small. Consistent with experimental results from other parts of the Western Australian wheat belt, modification of rooting depth appears to present the best option to reduce drainage beneath annual crops.     

Deformation analysis of composite reinforcing fabrics through yarn pull-out, drape and shear tests

This study reveals a new method based on image processing of bias extension test results to determine shear angle that characterizes the shear properties of fabric reinforcements. This way the simple and exact determination of shear angle with conventional devices is solved. The new method was tested on fabric reinforcements made of carbon, aramid and glass fibers and the results were compared with that of two known versions of bias extension tests. The analysis of the relation between shear angle and other deformation properties that characterize spatial deformation behavior involved the comparison of shear test results with yarn pull-out and drape tests carried out with special methods.     

The combined tensile and torsional behavior of irregular fibers

Most fibers are irregular, and they are often subjected to combined loading conditions during processing and end-use. In this paper, polyester and wool fibers under the combined tensile and torsional loads have been studied for the first time, using the finite element method (FEM). The dimensional irregularities of these fibers are simulated with sine waves of different magnitude and frequency. The breaking load and breaking extension of the fibers at different twist or torsion levels are then calculated from the finite element model. The results indicate that twist and level of fiber irregularity have a major impact on the mechanical properties of the fiber and the effect of the frequency of irregularity is relatively small.     

Basic properties of grain by-products and their viability in polypropylene composites

The objective was to study the potential of grain by-products (husk) of grains such as wheat (Triticum aestivum L; German name is Weizen) and rice (Oryza sativa) as reinforcements for thermoplastics as an alternative to or in combination with wood fibres. Prior to composites preparation, the chemical components of fibres such as cellulose, hemi-cellulose, lignin, starch, protein and fat were measured and the surface chemistry and functionality of grain by-products were studied using EDX and FT-IR. Structural constituents (cellulose, starch) were found in wheat husk (W) equal 42%, in rice husk 50% and in soft wood 42%, respectively. Thermal degradation characteristics, the bulk density, water absorption and the solubility index were also investigated. Wheat husk (W) and rice husk were found thermally stable at temperatures as low as 178 °C and 208 °C, respectively. The particle morphology and particle size were investigated using microscopy. Water absorption properties of the fibres were studied to evaluate the viability of these fibres as reinforcements. Polypropylene composites were fabricated using a high speed mixer and an ensuing injection moulding process with 40 wt% fibre. The tensile and Charpy impact strength of the resulting composites were investigated. The tensile elongation at break was found to 75% for wheat husk (W) composites and 23% for rice husk composites better than soft wood composites. Rice husk composites showed 13% better Charpy impact strength than soft wood composites. Due to coupling agent, tensile strength of composites found to improve 25% for soft wood, 35% for wheat husk (W) and 45% for rice husk.     

Mechanical analysis of geocomposites consisting of multi-axial warp knitted fabric and nonwoven mat

An eco-friendly shore protection system for preventing the erosion of shore surfaces has been developed using water permeable geocomposites that allow grass to take root in them. The geocomposites require enough stiffness to resist the flow of the water in the stream and good permeability of the flowing water. In this study, a geocomposite is designed using multi-axial warp knitted fabric (MAWKF) and nonwoven mats to ensure both the mechanical stiffness and water absorption. Firstly, a stress analysis is performed for a shore protection system to calculate stresses which are imposed onto geocomposites. To test geocomposites?? capacity to withstand the stress, the geometrical modeling of a MAWKF is carried out and the mechanical behavior of its unit-cell is analyzed using finite element method. Comparing the predicted results with experiments, the validity of the current modeling is demonstrated. Finally the adaptability of the geocomposite is evaluated using the calculated deformation.     

Effects of flax lignin addition on enzymatic oxidation of poly(ethylene adipate) urethanes

Lignin use in polymer industry has recently become very attractive from both economical and environmental reasons. In the specific case of blending, the addition of low lignin amounts was found to improve the properties and extends the application field of other natural or synthetic polymers, but the effects of oxidative enzymes on resulting blends are widely unknown. Thereby, the current study was carried out to determine some potential effects of small flax lignin concentrations (4.2 and 9.3 wt%) on the enzymatic degradation of a poly(ethylene adipate) urethane (PU). Thin cast films of PU and its lignin blends were incubated for 3 days at 30 °C with buffered solutions of fungal peroxidase and laccase extracted from Aspergillus sp., and compared with the untreated ones. Changes in surface structure and morphology were investigated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM), while the impact on bulk was assessed from tensile tests and thermogravimetry analysis (TGA). Although the addition of flax lignin reduces the surface structural modifications after enzyme treatment, the morphology, tensile and thermo-oxidative characteristics are still affected, with laccase showing the higher degradative efficiency. The lignin concentration, its high impact on the resulting blends morphology and relative low resistance to laccase and peroxidase degradation was the most important factors proved to driven the enzymatic oxidation.     

Effects of heat tolerance on expression of resistance toPresudomonas solanacearum E. F. Smith in potato

Summary Twelve potato clones with different genetic background for resistance to bacterial wilt and adaptation were tested for resistance to a race 1 and a race 3 isolate of the pathogen at three locations in the Philippines representing different ranges of ambient temperature. The results showed that the genes for heat tolerance are crucial for resistance. Stability analysis indicated that clones with both resistance and heat tolerance genes displayed higher and more stable resistance to the race 1 isolate than those clones having only resistance genes. The latter group tended to have higher values of both regression of disease index on environmental index and deviation from the regression in the stability analysis. Host — pathogen interaction effects were found to be statistically significant but small compared to main effects of isolates and clones. The involvement of genes with different effects on wilt resistance is discussed. Introduction     

Effect of hollow polyester fibres on mechanical properties of knitted wool/polyester fabrics

The physical and mechanical characteristics of hollow polyester fibres were compared with solid polyester fibres in order to establish their processing behaviour and performance characteristics. The effects of hollow fibres on fabric properties were investigated by using microscopy and tests of tensile and bursting strength, pilling, abrasion resistance, water vapour permeability, and handle. The results show that tensile strength of hollow polyester fibres and yarns are negatively affected by the cavity inside the fibre. Hollow fibres also have higher stiffness and resistance to bending at relaxed state. Fabrics made from hollow polyester/wool blends and pure wool fabrics show three distinguishable steps in pilling. During pilling, hollow fibres break before being pulled fully out of the structure, leading to shorter protruding fibres. Microscopy studies showed that the breakdown of hollow fibres started during entanglement by splitting along the helical lines between fibrils. KES results showed that the friction between fibres and the fibre shape are the most important parameters that determine the fabric low stress mechanical properties. However, in some aspects, the hollow structure of the fibre does not have a significant effect.