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ABSTRACTTechnologies like bunch covers have been shown to improve quality of date fruits. It is one of the approaches which are believed effective to protect the most sensitive stage of date fruit from autumnal rain and carob date. An experimental procedure is set up to allow farmers to predict, analyze, and optimize cover bunch performance after its use in protection applications and to select the ideal bag. The cover quality is designed based on a mathematical model and further optimized using MINITAB. From this analysis, the impact of each individual parameter on the desired response parameters has been studied. The results proved that the best cover could be found in optimal conditions. Using the influential parameters as tear strength, tensile strength, weight, air permeability and resistance to water penetration, the results indicate that the cover bunch remains influenced after harvesting period by the resistance to water penetration properties and tear strength as well.

Recognizing the importance of using plant fibers in polymeric composites and the no availability of data on fine structure, physico-chemical, morphological and others properties of Typha Angustata stem fibers, a study was undertaken with the objective of determining some of these properties. In this work, untreated and treated Typha stem fibers by NaOH treatment have been extracted and characterized to evaluate and compare their surface condition as well as their chemical composition, their fine structure and their mechanical properties. Typha stem treated fibers (TSTFs) have presented best results with an alpha-cellulose content of 51.3%, a density of 1460 kg/m3, an average tensile strength equal to 9.42cN/tex and a diameter of 208.12 µm. Also, Crystallinity Index (CI) of TSTFs was 57.4%. Unsaturated polyester matrix was reinforced with TSTFs and mechanical properties were undergone. Results show that TSTFs could be used for sustainable fiber-reinforced polymer composites with an enhancement in flexural and tensile tests for 12.6% TSTFs ratio.

Water injury and fungus infection are the main causes of large economic deterioration and losses in the quality of date fruits during harvesting period. The nonwoven bagging product was used for the first time on date palm and has been shown to efficiently protect date fruit from heavy rain and sunburn that reduces the rate of transpiration and increases fungus spoilage. The aim of this study is to evaluate the potential applicability of COMSOL code in simulating the heat transfer behavior through nonwoven date cover. The study also intended to use finite element method and adaptive mesh refinement technique to increase the accuracy of the solution and create model for efficient simulation of heat exchange in nonwoven bag. The proposed model was validated by the uniformity between simulating and experimental results. A detailed numerical study was conducted to find the influence of air permeability on heat transfer through nonwoven textiles. Results demonstrated that the reduction of nonwoven permeability is beneficial to minimize the heat taken away by forced convection by decreasing the inner air transportation.

The kenaf fibers were used to reinforce composites with two structures: nonwoven and bulk fibers and with treated and untreated kenaf fiber. A series of tensile tests were conducted on these composites. The use of kenaf fibers allows having composite with improved mechanical properties compared to pure polyester composite. This increase reaches 56.15% in strength and 137.85% in strain when varying the fiber weight ratio and the reinforcement structure. The interested results for both tensile strength and strain are obtained for nonwoven structure made by untreated fiber. The statistical study reveals that the most influencing parameter in tensile properties was the reinforcement weight ratio. The optimum composite was obtained when using a nonwoven structure made with untreated fiber with 11.10% fiber weight ratio.

This paper presents the results of the first kenaf spinning attempt in Tunisia. Indeed, kenaf fibers are rigid and lack of cohesion that makes their spinning difficult and a challenge. So, this paper describes the possibility of spinning different blends of kenaf/cotton fibers using open end spinning machine. Five different blends of kenaf/cotton (M1:10/90, M2:20/80, M3:30/70, M4:40/60, and M5:50/50) were considered. The higher kenaf content in the blend make spinning process difficult and even impossible. The produced yarns were characterized to evaluate their mechanical properties and compare it to similar yarn performances. These blends gave different yarn counts varying from 41.86 to 69.16 tex, tenacity of 8.80 cN/tex to 10.07 cN/tex, while elongation at break of 7% to 8.93%. The results proves that kenaf/cotton 40/60 blend ratio presents the better mechanical properties and regularity with 8.80 cN/tex for tenacity and 7.68% for elongation with good regularity index Ireg = 1.25.

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers. Researchers over the years have explored many plant fibers using different extraction processes to study their physical, chemical, and mechanical properties. In this context, the present study relates to the extraction, characterization, and optimization of Typha angustata L. stem fibers. For this purpose, desirability functions and response surface methodology were applied to simultaneously optimize the diameter (D), linear density (LD); yield (Y), lignin fraction (L), and tenacity (T) of Typha stem fibers. Typha stems have been subjected to both alkali (NaOH) and enzymatic (pectinex ultra-SPL) treatments. Three levels of process variables including enzyme concentration (10, 15, and 20 ml/L) and treatment duration (10, 15, and 20 days) were used to design the experiments according to the factorial design. Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis. The Derringer's desirability function released that the values of process variables generating optimized diameter, linear density, yield, lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration, respectively. Confirmation was performed and high degree of correlation was found between the experimental and statistical values. Moreover, the morphological structure has been investigated by the scanning electron microscope, showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber. Compared to Typha stem non-treated fibers (TSNTF), Typha stem combined treated fibers (TSCTF), brings to improve mechanical properties. This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of (66.86%) and lignin ratio of (10.83%) with a crystallinity index of (58.47%). [ABSTRACT FROM AUTHOR]

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents the study of the tensile characteristics of the Typha fiber reinforced polyester composites. Composites have been developed by hand lay-up technique with different Typha fibers treated conditions (sea water, alkali and combined treatment), different volume fraction and reinforcement origin (Leaf or Stem fibers) and structure (mixture of fibers or nonwoven structure). The experimental results indicated an improvement in tensile strength with increasing fiber content. Thus, a maximum tensile strength was observed and was equal to 24.58 and 25.07 MPa, respectively, for a fiber content of 12.6% of the leaf fibers and 10.3% of the typha stalk fibers. Mercerization has successfully modified the structure of fibers and improved the performance of Typha fiber composites by promoting better fiber to resin bonding. Statistical analysis shows that the optimum solution was obtained by using a bulk structure having a rate of 12.6% for the extracted fibers from the chemically treated stems. [ABSTRACT FROM AUTHOR]

This paper deals with the effect of the chemical treatment, fibre ratio and fibre reinforcement structure on the flexural properties of kenaf-polyester composites. Composites were made from an unsaturated polyester matrix reinforced with an alkali-treated and virgin kenaf fibres in a loose fibres and nonwovens. Results reveal that alkali treatment improves the flexural properties of composites expect elongation. The same result was obtained when using a nonwoven structure us reinforcement. The best flexural properties were observed for 11.1% fibre weight ratio with the nonwoven structure reinforce composite. The flexural strength and the flexural modulus were 69.5 MPa and 7.11 GPa, respectively, for this composite while it was 42.24 MPa and 3.61, respectively, for polyester samples (no fibre reinforcement). A statistical study was carried out in order to study the effect of the alkali treatment, reinforcement structure and the reinforcement weight ration on the composite properties. This study proved that the parameter with most impact on the measured properties is the fibre-to-matrix weight ratio. And also this study aims to determine the optimum parameters allowing maximising all measured properties and we found that when using a nonwoven structure made with chemically-treated fibre at 11.10% fibre weight ratio, is the optimum solution. [ABSTRACT FROM AUTHOR]

The influence of temperature, duration and soda (NaOH) concentration on the extraction yield, linear density, diameter, tenacity and lignin ratio of Typha leaf fibres has been studied. A factorial design of experience has been used to identify the optimum operating conditions, and equations relating to the dependent variables to the operational variables of the extraction process are established. The optimum extraction condition has been determined by the statistical study using response surface and desirability function. The morphology of the obtained fibres and chemical constituents are determined. Fibres, extracted from leaves of Typha with the optimum process, have a lignin content value of about 14% like jute, alpha-cellulose value of about 67% similar to pineapple and jute fibres, extractives content value of about 1%, starches content value of about 2% and ash content value of about 1%. Finally, the characteristics of the optimum Typha fibre are compared with those of other vegetable fibres, showing large diameter and low mechanical properties as compared to other vegetable fibres. [ABSTRACT FROM AUTHOR]

This article studies the influence of the pulping conditions of Agave americana L. [temperature (100-120°C), pulping time (60-120 mn) and soda concentration (4-8%)] on the pulp yield, kappa index, brightness, viscosity, and the hand sheets breaking length, tear index, and burst index. Responses of pulp and hand sheets properties to the process variables were analyzed using statistical software (Minitab 14). Pulp has been studied using a factorial design to identify the optimum operating conditions, equations relating the dependant variables to the operational variables of the pulping process were established. Results showed that acceptable physical and mechanical properties of pulps and paper could be achieved at 107°C, for 60 mn, and 6% of soda concentration. These are the most suitable conditions for obtaining paper sheets with a high breaking length and tear and burst indexes. Test sheets made from pulped agave leaf fibers were compared to paper made from other vegetable fibers (pine, agave tequilana, and eucalyptus fibers). [ABSTRACT FROM AUTHOR]