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Fiber Content (fiber + content)
Kinds of Fiber Content Selected AbstractsWater absorption properties of phosphate glass fiber-reinforced poly-,-caprolactone composites for craniofacial bone repairJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Levent Onal Abstract The moisture uptake of polymers and composites has increasing significance where these materials are specified for invasive, long-term medical applications. Here we analyze mass gain and the ensuing degradation mechanisms in phosphate glass fiber reinforced poly-,-caprolactone laminates. Specimens were manufactured using in situ polymerization of ,-caprolactone around a bed of phosphate glass fibers. The latter were sized with 3-aminopropyltriethoxysilane to control the rate of modulus degradation. Fiber content was the main variable in the study, and it was found that the moisture diffusion coefficient increased significantly with increasing fiber volume fraction. Diffusion, plasticization, and leaching of constituents appear to be the dominant aspects of the process over these short-term tests. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Creep behavior of biocomposites based on sisal fiber reinforced cellulose derivatives/starch blendsPOLYMER COMPOSITES, Issue 3 2004Vera A. Alvarez Biodegradable composites based on cellulose derivatives/starch blends reinforced with sisal short fibers were fabricated by injection molding. Results of short-term flexural creep tests are reported to investigate the time-dependence behavior of the composites. Fiber content and temperature effects are also considered, taking into account various methods and equations. At short times, a creep power law is employed. A master curve with the Arrhenius model is used to determine the creep resistance at longer times and different temperatures. Good fitting of the experimental results with the four-parameter model is reported, leading to a relationship between the observed creep behavior and the composite morphology. The addition of sisal fibers to the polymeric matrix promotes a significant improvement of the composite creep resistance. Polym. Compos. 25:280,288, 2004. © 2004 Society of Plastics Engineers. [source] Effect of Plant Factors, Sugar Contents, and Control Methods on the Top Borer (Scirpophaga nivella F.) Infestation in Selected Varieties of SugarcaneENTOMOLOGICAL RESEARCH, Issue 3 2005Abdul KHALIQ ABSTRACT Sugarcane (Saccharum officinarum L.) varieties CP-43/33 and L-118 susceptible, BF-162 and SPSG-26 resistant while CP-72/2086 as intermediate were screened for studies on top borer, Scirpophaga nivella Fabricus (Pyralidae: Lepidoptera). Morpho-physio chemical plant factors as well as quality of sugar were examined to elucidate the relationship between pest infestations. The observations on leaf thickness 0.735* and moisture contents 0.771* showed positive and significant correlation with the pest infestation at tillering stage. Total minerals, manganese and copper contents did not show significant correlation with the pest infestation, whereas nitrogen, potassium, calcium, magnesium and ferrous contents manifested positive and significant correlation with the pest infestation. Phosphorous, carbohydrates, fats and zinc produced significant and adverse effect on the pest infestation at tillering stage. Zinc contents with contrasting behaviors appeared to be the most important character with co-efficient value of 0.764 followed by ferrous with positive sign. The effect of borer infestation was significantly negative on pol (sucrose), Brix contents (total soluble solids), and CCS (commercial cane sugar). The coefficient of determination value was 0.821, obtained by computing fiber content, pol, Brix and CCS factors together for multivariate regression models. Application of trash mulching at the time of sowing proved to be the most effective treatment with minimum infestation (3.91%) of borer and maximum protection level (62.87%) followed by Furadan®, removal of dead hearts + spike thrust, hand collection of egg masses, and cutting of shoots at 15 days interval. [source] Polypropylene Fibers and their Effects on Processing Refractory CastablesINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2007Rafael Salomão Polymeric fibers are efficient drying additives for refractory castables as they can reduce the risks of explosion during the first heat-up. When fibers are melted, they increase permeability, enhancing the drying rate and reducing vapor pressure. Despite these benefits, adding fibers can induce mixing and pumping difficulties due to particle entanglement. In the present work, an analysis involving rheology, dynamic permeability, drying and explosion likelihood of polypropylene fiber containing castables is presented. An optimized condition (fiber content and geometry) to maximize the performance of fibers as drying additives and to prevent mixing drawbacks is also highlighted. [source] Direct fluorination of Twaron fiber and investigation of mechanical thermal and morphological properties of high density polyethylene and Twaron fiber compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008J. Maity Abstract Composites consisting of high density polyethylene (HDPE) reinforced with randomly oriented chopped Twaron fibers (both fluorinated and nonfluorinated) show a significant increase in mechanical and thermal properties. To increase the better fiber matrix adhesion, the Twaron fiber is surface fluorinated using elemental fluorine. The surface of the Twaron fiber becomes very rough and the diameter of Twaron fiber increases from , 12 to 14 ,m after fluorination. The composites were prepared using solution method to overcome the damage of the fiber. The tensile strength and the Young's modulus increases with increasing fiber content. The tensile strength and modulus of modified fiber (fluorinated Twaron fiber) composites is much higher than nonmodified fiber composites indicating that there is better mechanical interlocking between the modified fiber and the matrix. Thermal properties obtained from DSC and DTA-TG analysis of the fluorinated fiber composites are also improved. Contact angle measurements, as well as the surface energy measurements, indicate that the composites are more wettable and is maximum for fluorinated fiber composites i.e., surface energy for fluorinated fiber composites is highest. Crystallinity is also higher for fluorinated fiber composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Thermal properties of extruded/injection-molded poly(lactic acid) and biobased composites,,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Abdellatif A. Mohamed Abstract To determine the degree of compatibility between poly(lactic acid) and different biomaterials (fibers), poly(lactic acid) was compounded with sugar beet pulp and apple fibers. The fibers were added in 85 : 15 and 70 : 30 poly(lactic acid)/fiber ratios. The composites were blended by extrusion followed by injection molding. Differential scanning calorimetry and thermogravimetric analysis were used to analyze the extruded and extruded/injection-molded composites. After melting in sealed differential scanning calorimetry pans, the composites were cooled through immersion in liquid nitrogen and aged (stored) at room temperature for 0, 7, 15, and 30 days. After storage, the samples were heated from 25 to 180°C at 10°C/min. The neat poly(lactic acid) showed a glass-transition transition at 59°C with a change in heat capacity (,Cp) value of 0.464. The glass transition was followed by crystallization and melting transitions. The enthalpic relaxation of the poly(lactic acid) and composites steadily increased as a function of the storage time. Although the presence of fibers had little effect on the enthalpic relaxation, injection molding reduced the enthalpic relaxation. The crystallinity percentage of the unprocessed neat poly(lactic acid) dropped by 95% after extrusion and by 80% for the extruded/injection-molded composites. The degradation was performed in air and nitrogen environments. The degradation activation energy of neat poly(lactic acid) exhibited a significant drop in the nitrogen environment, although it increased in air. This meant that the poly(lactic acid) was more resistant to degradation in the presence of oxygen. Overall, injection molding appeared to reduce the activation energy for all the composites. Sugar beet pulp significantly reduced the activation energy in a nitrogen environment. In an air environment, both sugar beet pulp and apple fibers increased the activation energy. The enzymatic degradation of the composites showed a higher degradation rate for the extruded samples versus the extruded/injection-molded composites, whereas the apple composites exhibited higher weight loss. The thermogravimetric analysis data showed that the degradation of unprocessed and extruded neat poly(lactic acid) followed a one-step mechanism, whereas extruded/injection-molded composites showed two-step degradation. A higher fiber content resulted in up to three-step degradation mechanisms. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Preparation of rubber composites from ground tire rubber reinforced with waste-tire fiber through mechanical millingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Xin-Xing Zhang Abstract Composites made from ground tire rubber (GTR) and waste fiber produced in tire reclamation were prepared by mechanical milling. The effects of the fiber content, pan milling, and fiber orientation on the mechanical properties of the composites were investigated. The results showed that the stress-induced mechanochemical devulcanization of waste rubber and the reinforcement of devulcanized waste rubber with waste-tire fibers could be achieved through comilling. For a comilled system, the tensile strength and elongation at break of revulcanized GTR/fiber composites reached maximum values of 9.6 MPa and 215.9%, respectively, with 5 wt % fiber. Compared with those of a composite prepared in a conventional mixing manner, the mechanical properties were greatly improved by comilling. Oxygen-containing groups on the surface of GTR particles, which were produced during pan milling, increased interfacial interactions between GTR and waste fibers. The fiber-filled composites showed anisotropy in the stress,strain properties because of preferential orientation of the short fibers along the roll-milling direction (longitudinal), and the adhesion between the fiber and rubber matrix was improved by the comilling of the fiber with waste rubber. The proposed process provides an economical and ecologically sound method for tire-rubber recycling. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4087,4094, 2007 [source] QUALITY OF BREAD SUPPLEMENTED WITH POPPED AMARANTHUS CRUENTUS GRAINJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2008A-SOLAROV, MARIJA BODRO ABSTRACT The addition of popped Amaranthus cruentus grain to wheat bread formulation at 10, 15 and 20% levels (flour basis) was carried out to test the effects on sensory and nutritional characteristics of the supplemented bread samples. The addition of popped amaranth grain increased ash, protein and crude fiber content significantly. Zinc content increased by 42.6,74.6%, manganese content by 51.7,90.8%, magnesium content by 75.7,88.0% and calcium content by 57,171% in the supplementation ranges from 10 to 20% of popped amaranth grain. Bread samples supplemented with popped grains had a significantly higher content of squalene in comparison with the control sample (8,12 times higher). Loaf volume of supplemented bread samples decreased from 3.54 to 2.36 mL/g. Also, a significant increase in crumb hardness and lower crumb elasticity was observed. The supplementation contributed to denser crumb structure, more uniform porosity, improved crust color and flavor. It might be concluded that supplementation levels up to 15% (flour basis) were sensorially acceptable. PRACTICAL APPLICATIONS Bread made from refined wheat flour, besides being a good source of energy, is considered to be nutritionally poor. Therefore, the addition of inexpensive staples with superior nutritional quality such as some pulses, cereals or pseudocereals to wheat flour could improve the nutritional quality of wheat products. Amaranth is a pseudocereal that contains high levels of fat, dietary fibers, lysine and minerals, especially calcium and magnesium. The addition of amaranth grain to wheat bread contributes to higher intakes of proteins, fibers, fat and minerals. The usage of popped amaranth grain is advantageous because it excludes the need for grain milling and the necessity for preparative steps before mixing in bakeries. In addition, thermal treatment increases the protein efficiency ratio and gelatinizes starch that affects positively the stability, strength and freshness of the crumb. Popped amaranth grain also contributes to the pleasant taste and overall acceptability of supplemented bread. [source] BAKING PROPERTIES OF MILK PROTEIN-COATED WHEAT BRAN,JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2008CHARLES I. ONWULATA ABSTRACT Increasing the dietary fiber content of formulated foods will benefit the health and nutrition of consumers. The problem is that it is difficult to add substantial amounts of dietary fiber to formulated foods. Fiber absorbs significant amounts of water from surrounding ingredients creating texture problems such as soggy and dry patches in the foods. In this study, red wheat bran milled and sieved smaller than 140 microns was coated by spraying with a 50/50 emulsion of whey protein isolates (WPIs) and casein. WPI and casein emulsion was produced first by blending and shearing the milk proteins in ice and water and then evaporating under partial vacuum for 75 min at 45C. Cookies and muffins made with the milk protein-coated red wheat (MPCF) bran and the noncoated wheat bran (NCF), replacing 5, 10 and 15 wt % of the flour, were compared to control cookies and muffins made without added fiber. The water-holding capacity (WHC) of the MPCF and NCF was determined along with their moisture, color, hardness, and volume in the baked cookies and muffins. There was a significant (P < 0.01) improvement (250%) in loss of WHC of MPCF over NCF. In cookies, MPCF absorbed significantly less water and was slightly darker at 5 wt % substitution than NCF, but was between 12 to 60% higher in baked volume than the control. MPCF muffins were lighter in color and harder except for the 5 wt % muffins that were softer and higher in percent baked volume. Adding up to 15-g MPCF per 100 g batter can be added to baked cookies and muffins to increase fiber content and improve WHC and volume. PRACTICAL APPLICATIONS This study determined that coating wheat bran with specially treated dairy proteins reduced the amount of water the bran can absorb when added up to 15 wt% to formulations, or in the finished products, helping to maintain textural integrity of products. The intact wheat bran remains available for its functional health enhancing roles when consumed and digested. This knowledge allows the creation of nutritious high-fiber products with desirable texture. [source] Calcium Absorption from Commonly Consumed Vegetables in Healthy Thai WomenJOURNAL OF FOOD SCIENCE, Issue 9 2008S. Charoenkiatkul ABSTRACT:, The absorbability of calcium from ivy gourd, a green leafy vegetable (Coccinia grandix Voigt.) and winged bean young pods (Psophocarpus tetragonolobus [L] DC) were measured in 19 healthy adult women aged 20 to 45 y, in a 3-way, randomized-order, crossover design with an average calcium load of 100 mg and milk as the referent. The test meals were extrinsically labeled with 44Ca and given with rice as breakfast after an overnight fast. Absorption of calcium was determined on a blood sample drawn 5 h after ingestion of the test meal. Fractional calcium absorption (X± SD) was 0.391 ± 0.128 from winged beans, 0.476 ± 0.109 from ivy gourd, and 0.552 ± 0.119 from milk. The difference in fractional calcium absorption for these 2 vegetables was significant (P < 0.05) and the fractional calcium absorption from these 2 vegetables were both significantly lower than from milk. The difference was partly accounted for by the phytate, oxalate, and dietary fiber content of the vegetables. However, calcium bioavailability of these 2 vegetables, commonly consumed among Thais, was relatively good compared to milk (71% to 86% of milk) and could be generally recommended to the public as calcium sources other than milk and Brassica vegetables. [source] Hard Red Winter Wheat/Nutrim-OB Alkaline Fresh Noodles: Processing and Texture AnalysisJOURNAL OF FOOD SCIENCE, Issue 1 2005Abdellatif A. Mohamed ABSTRACT: Nutrim was added at 10%, 20%, and 30% to Hard Red Winter wheat flour to increase soluble fiber content of fresh noodles to a minimum of 0.75 g/noodle serving (one noodle serving is 42 g or 40 g db (dry basis). The effect of Nutrim on the dough characteristics and noodles quality was tackled. The presence of Nutrim increased the final water absorption and dough tolerance as measured by Farinograph whereas the dough stability was decreased. The DSC (Deferential scanning Calorimetry) data showed that Nutrim increased the onset or peak temperatures while the ,H was reduced by 25%. The resilience of Nutrim-enriched noodles was not significantly affected. The chewiness and hardness were reduced by Nutrim added at 20% and 30%, while cohesiveness was significantly increased by all 3 Nutrim levels. RVA (Rapid Visco Amylograph) profile showed higher peak viscosity in the presence of Nutrim. The 20% and 30% Nutrimlevels increased the soluble fiber of the final product from 1.13% to 1.67% and 2.47%. The yellow color of noodles became darker with higher Nutrim amounts added. The addition of Nutrim produced dough with a more compact image with less space between the starch granules as measured by scanning electron microscopy when compared with the control. The rheological testing showed that the presence of Nutrim decreased flour suspension elastic properties. [source] Extraction and Application of Dietary Fiber and Cellulose from Pineapple CoresJOURNAL OF FOOD SCIENCE, Issue 4 2002T. Prakongpan Pineapple core dietary fiber (PDF) was obtained by alcoholic extraction; pineapple core cellulose (PC) was a product of alkali extraction with a bleaching process. Total dietary fiber content of PDF and PC was 99.8% and 95.2% (dry basis), respectively, and their water activity was 0.25. PC contained 91.2% cellulose with a pH value of 4.0, while that of PDF was 6.2. The fiber product with large particle size gave higher values than the product with smaller particles for pH, water and oil retention capacity, settling volume and emulsifying activity. Both had rough, pitted surfaces and presented showed good functions in cake-type doughnuts, golden layer cake and beef burgers. [source] SENSORY DESCRIPTIVE ANALYSIS, SENSORY ACCEPTABILITY AND EXPECTATION STUDIES ON BISCUITS WITH REDUCED ADDED SALT AND INCREASED FIBERJOURNAL OF SENSORY STUDIES, Issue 4 2009MARISA BEATRIZ VÁZQUEZ ABSTRACT The aims of this study were to formulate biscuits with 50% more fiber and 50% less added salt than classic formulations, to describe their sensory characteristics, to measure expectation/sensory acceptability, and to investigate if sensory acceptability for these biscuits was related to the interest in consuming food products with less salt and/or more fiber content. A 2 × 2 factorial design was used to develop four formulations: conventional fiber/conventional salt; conventional fiber/reduced salt; increased fiber/conventional salt; and increased fiber/reduced salt. Differences in the sensory profiles measured by a trained panel were of low magnitude, except for presence and taste of bran. Adolescent and adult consumers evaluated acceptability in three stages: blind with three-digit codes; expectation of the label only; and biscuit + label. The low salt formulations received the lowest scores in the expectation stage, but in the blind and biscuit + label stages acceptability of all formulations was similar. The variables that explained overall acceptance were: measurement stage; formulation salt level; interest in reducing consumption of high salt foods; and interest in consuming bakery products with fiber. PRACTICAL APPLICATIONS Increasing fiber content of biscuits by 40 to 50% helps achieve recommendations to increase fiber intake in daily diets. Also, as biscuits currently on the Argentine and other world markets present two extreme varieties , with or without added salt , formulating a biscuit with 50% less added salt facilitate sodium reduction. In our research we have found that these goals can be achieved without seriously affecting sensory acceptability. We propose the articulation of the necessary strategies with the food industry to market biscuits with less added salt and more fiber for the general population; and the use of these healthier biscuits by institutional food services. [source] Development of low-fat mayonnaise containing polysaccharide gums as functional ingredientsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2010Hou-Pin Su Abstract BACKGROUND: The objective of this study was to develop a low-fat (LF) mayonnaise containing polysaccharide gums as functional ingredients. Xanthan gum (XG, 15 g kg,1), citrus fiber (CF, 100 g kg,1) and variable concentration of guar gum (GG) were used to formulate the optimum ratios of polysaccharide gums as fat replacers. The fat content in LF mayonnaise was reduced to 50% if compared with full-fat (FF) mayonnaise, and the products still maintained ideal rheological properties. RESULTS: The rheological parameters showed that there were no (P > 0.05) differences in yield stress, viscosity and flow behavior index between XG + 10 g kg,1 GG, CF + 5 g kg,1 GG and FF control. LF mayonnaises had lower caloric values and higher dietary fiber content than the FF counterpart. Scanning electron microscopy (SEM) micrographs illustrated that the network of aggregated droplets in LF treatments contained a large number of interspaced voids of varying dimensions. Furthermore, in a comparison of sensory evaluation of LF treatments with commercial and our FF mayonnaises, there were no (P > 0.05) differences in any sensory scores among XG + 10 g kg,1 GG control. CONCLUSION: This study shows that XG + 10 g kg,1 GG and CF + 5 g kg,1 GG could be used in LF mayonnaise formulations based on its multiple functions on processing properties. Copyright © 2010 Society of Chemical Industry [source] Effect of enzymes, flavor and organic acids on nutrient digestibility, performance and carcass traits of growing,finishing pigs fed diets containing dehydrated lucerne mealJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2009Philip A Thacker Abstract BACKGROUND: We recently determined that 150 g kg,1 of lucerne meal can be fed during the finishing period without detrimental effects on pig performance but lucerne should be limited to less than 75 g kg,1 during the growing period. Lucerne has a high fiber content, is poorly digested and contains antinutritional factors such as saponins which reduce palatability. Therefore, pig performance could be enhanced by supplementing lucerne-containing diets with feed additives such as flavors, enzymes or organic acids. The objective of this study was to determine the effects of these additives on nutrient digestibility, performance and carcass traits when fed to growing-finishing swine fed diets containing lucerne. RESULTS: Flavor and enzyme had no effect on nutrient digestibility, pig performance or carcass traits. During the growing period, inclusion of propionic and acetic acids increased (P < 0.05) the digestibility of dry matter, protein and energy. Weight gain and intake also increased (P < 0.05). None of the additives had any effect on pig performance during the finishing period or on carcass traits. CONCLUSION: During the growing period, including 200 g kg,1 lucerne was detrimental to pig performance. Addition of organic acid improved pig performance and nutrient digestibility. During the finishing period, 200 g kg,1 lucerne can be successfully incorporated into pig diets without negative effects on pig performance. Copyright © 2008 Society of Chemical Industry [source] Forage quality and tannin concentration and composition of a collection of the tropical shrub legume Flemingia macrophyllaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2006Meike S Andersson Abstract A collection of 23 Flemingia macrophylla (Willd.) Merrill accessions of different growth habits and contrasting digestibility and one Flemingia stricta reference accession were assessed for forage quality with particular emphasis on digestibility, condensed tannin concentration and fiber content. Large differences in in vitro dry matter digestibility (IVDMD) (356 to 598 g kg,1), content of crude protein (CP) (121 to 254 g kg,1) and extractable condensed tannins (CT) (0 to 268 g kg,1), protein-binding capacity of extractable CT or astringency (1.7 to 7.9 protein-binding entities) (PBE) and monomer composition of extractable CT were detected. IVDMD and extractable CT were negatively correlated and extractable CT was positively correlated with protein-binding capacity. Prodelphinidin was positively and propelargonidin negatively correlated with protein-binding capacity of extractable CT. The accessions CIAT 18438, CIAT 21083, CIAT 21090 and CIAT 22082 were superior to the most widely used accession CIAT 17403 in terms of forage quality and could be an option in production systems with acid infertile soils. In future evaluations, particular attention needs to be paid to chemical and structural features related to the composition of extractable CT and their effect on nitrogen utilization by ruminants. Copyright © 2006 Society of Chemical Industry [source] Comparative study of the effects of chlorinated polyethylene and acrylic impact modifier on the thermal degradation of poly(vinyl chloride) compounds and poly(vinyl chloride)/(oil palm empty fruit bunch) compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2010Aznizam Abu Bakar The effects of chlorinated polyethylene (CPE) and acrylic impact modifier (AIM) on the thermal degradation of poly(vinyl chloride) (PVC) compounds and composites were investigated. The amounts of AIM and CPE used were fixed at 9 parts per hundred parts of resin (phr), while oil palm empty fruit bunch (OPEFB) fiber content was increased from 0 to 40 phr. To produce composites, the PVC formulations were dry-blended by using a laboratory blender before being milled into sheets on a two-roll mill at 165°C. The milled sheets were then hot-pressed at 180°C. The thermal degradation of the specimens was evaluated by using thermogravimetry in a nitrogen environment. Thermal stability of the PVC/CPE compounds and PVC/CPE/OPEFB composites was improved by the addition of CPE. The CPE retarded the dehydrochlorination of PVC. However, the stabilization effect was reduced by the incorporation of OPEFB at levels of 30 and 40 phr. The presence of AIM accelerated the dehydrochlorination of PVC/AIM compounds and PVC/AIM/OPEFB composites. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Compliance of the bladder neck supporting structures: Importance of activity pattern of levator ani muscle and content of elastic fibers of endopelvic fasciaNEUROUROLOGY AND URODYNAMICS, Issue 4 2003Matija Barbi Abstract Aims Firm bladder neck support during cough, suggested to be needed for effective abdominal pressure transmission to the urethra, might depend on activity of the levator ani muscle and elasticity of endopelvic fascia. Methods The study group of 32 patients with stress urinary incontinence and hypermobile bladder neck, but without genitourinary prolapse, were compared with the control group of 28 continent women with stable bladder neck. The height of the bladder neck (HBN) and compliance of the bladder neck support (C) were assessed, the latter by the quotient of the bladder neck mobility during cough and the change in abdominal pressure. By using wire electrodes, the integrated full-wave rectified electromyographic (EMGave) signal of the levator ani muscle was recorded simultaneously with urethral and bladder pressures. The pressure transmission ratio (PTR), time interval between the onset of muscle activation and bladder pressure increment (,T), and area under the EMGave curve during cough (EMGcough) were calculated. From bioptic samples of endopelvic fascia connecting the vaginal wall and levator ani muscle, elastic fiber content was assessed by point counting method. Mann-Whitney test was used to compare all the variables. Correlations between the parameters were evaluated by using the Spearman correlation coefficient. Results In the study group, HBN was significantly lower (P,<,0.001), C was significantly greater (P,<,0.001), and PTR was significantly lower (P,<,0.001). In the study group, the muscular activation started later (median, ,Tl, ,0.147 second; ,Tr, ,0.150 second), and in the control group, it preceded (,Tl, 0.025 second; P,<,0.001; ,Tr, 0.050 second; P,<,0.001) the bladder pressure increment. EMGcough on the left side was significantly greater in the study group (P,<,0.046). Elastic fiber content showed no difference between the groups. The analysis of all patients revealed negative correlations between C and PTR (r,=,,0.546; P,<,0.001) and between C and ,Tl (r,=,,0.316; P,<,0.018). Conclusions Firm bladder neck support enables effective pressure transmission. Timely activation of the levator ani seems to be an important feature. Neurourol. Urodynam. 22:269,276, 2003. © 2003 Wiley-Liss, Inc. [source] Mechanical properties of natural fibers/polyamides compositesPOLYMER COMPOSITES, Issue 3 2009Patricia Alvarez de Arcaya The aim of this investigation has been to use high performance thermoplastic matrices such as polyamides instead of the commonly used polyolefins to develop natural fiber composites for substituting glass fibers without renouncing to their mechanical properties. For this purpose, different natural fibers such as flax, jute, pure cellulose, and wood pulps have been melt compounded with different polyamides to analyze the effect of fiber content on mechanical properties. Fibers have not been treated as polyamides are less hydrophobic than polyolefins. Thermal behavior of the different fibers was determined by thermogravimetry to know the boundary for processing at high temperatures, since the melting points of the polyamides are much higher than those of polyolefins and this could lead to a higher degradation of the natural fibers. Rheological parameters were deduced by measuring torque values during the mixing process. Flexural and tensile modulus and strength of composites were analyzed, finding an increase in the mechanical properties compared with the unreinforced matrix that turns natural fibers into a considerable reinforcement offering a wealth of possibilities for industrial applications. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Three-dimensional fiber orientation in vibration welded joints of glass fiber reinforced polyamide-6POLYMER COMPOSITES, Issue 9 2008Musa R. Kamal A technique was developed to obtain the three-dimensional distribution of fiber orientation in vibration-welded joints of polyamide-6 (PA-6) reinforced with 30 wt% glass fibers. The heat-affected zone (HAZ) of fiber-reinforced PA-6 was successfully revealed by polishing and etching the vibration welded joints. Examination with the polarized light microscope in the reflection mode showed detailed microstructure domains, including the bulk crystalline zone and the HAZ. Experimental elliptical fiber cross-section images were used to obtain second order orientation tensors, thus providing a quantitative description of the three-dimensional fiber orientation distribution. The fibers in the HAZ were reoriented towards the squeeze flow direction, when compared with the bulk phase. Low welding pressure does not necessarily produce a more favorable fiber orientation in the tensile direction than high welding pressure. High welding pressure and low amplitude promote fiber reorientation in both the squeeze flow and tensile (weld thickness) directions. Overall, it was found that, at 30% fiber content, vibration-welded joints of injection molded fiber-reinforced PA-6 are weaker than vibration-welded joints in unreinforced injection molded samples. The fibers in the former do not undergo sufficient reorientation to influence weld strength in the tensile direction. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Development and high stress abrasive wear behavior of milled carbon fiber-reinforced epoxy gradient compositesPOLYMER COMPOSITES, Issue 7 2008Navin Chand Milled carbon fiber-reinforced polysulfide-modified epoxy gradient composites have been developed. Density and hardness increases with the increase of carbon fiber content in the direction of centrifugal force, which shows the formation of gradient structure in the composite. High stress abrasive wear test was conducted on the gradient composites by using a Suga Abrasion Wear Tester. Abrasive wear rate reduced on increase of milled carbon fiber content from 0.15 to 1.66 vol%. Reduction in abrasive wear rate in milled carbon fiber-reinforced epoxy gradient composites has been attributed to the increase of hardness, presence of random milled fibers, and debris of composite materials, which gave resistance and reduced wear rate. There is a small decrease in specific wear rate on adding 0.15 vol% milled carbon fibers. Further decrease of specific wear rate is observed on adding 0.45 vol% milled carbon fibers. After 3 N load, there is a decrease in specific wear rate behavior on adding 0.45 vol% carbon fibers, which further decreases on adding 0.60 vol% of carbon fibers. There is a remarkable decrease in specific wear rate up to 5 N load for 1.66 vol% milled carbon fiber-reinforced composite. Reduction in specific wear rate on adding milled carbon fibers is based on the formation of debris, which remained intact in their respective positions due to the interfacial adhesion between milled carbon fibers and epoxy resin. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Mechanical properties of wood plastic composite panels made from waste fiberboard and particleboardPOLYMER COMPOSITES, Issue 6 2008Majid Chaharmahali The possibility of producing wood-plastic panels using a melt blend/hot press method was studied in this research. The studied panels were compared with conventional medium density fiberboard (MDF) and particleboard (PB) panels. Wood-plastic panels were made from high density polyethylene (as resin) and MDF waste and PB waste (as natural fiber) at 60, 70, and 80% by weight fiber loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistances, and impact strength were studied. Results indicated that the mechanical properties of the composites were strongly affected by the proportion of the wood flour and polymer. Maximum values of flexural modulus of wood plastic panels were reached at 70% fiber content. Flexural strength, screw and nail withdrawal resistance, and impact strength of wood plastic composites declined with the increase in fiber content from 60 to 80%. This was attributed to the lack of compatibility between the phases. The produced panels outperformed conventional PB panels regarding their mechanical properties, which were acceptable when compared with MDF panels as well. The best feature in the produced panels was their screw withdrawal resistance, which is extremely important for screw joints in cabinet making. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] In-situ pultrusion of urea-formaldehyde matrix composites.POLYMER COMPOSITES, Issue 1 2006II: Effect of processing variables on mechanical properties Unidirectional fiber reinforced urea-formaldehyde (UF) composites have been prepared by the pultrusion processes. The effects of the processing parameters on the mechanical properties (flexural strength and flexural modulus, etc.) of the glass fiber reinforced UF composites by pultrusion has been studied. The processing variables investigated included die temperature, pulling speed, postcure temperature and time, filler type and content, and glass fiber content. The die temperature was determined from differential scanning calorimetry (DSC) diagram, swelling ratio, and mechanical properties tests. It was found that the mechanical properties increased with increasing die temperature and glass fiber content, and with decreasing pulling rate. The die temperature, pulling speed, and glass fiber content were determined to be 220°C, 20,80 cm/min, and 60,75 vol%, respectively. The mechanical properties reached a maximum value at 10, 5, 5, and 3 phr filler content corresponding to the kaolin, talc, mica, and calcium carbonate, respectively, and then decreased. The mechanical properties increase at a suitable postcure temperature and time. Furthermore, the properties that decreased due to the degradation of composite materials for a long postcure time are discussed. POLYM. COMPOS., 27:8,14, 2006. © 2005 Society of Plastics Engineers [source] Polyethylene-Palygorskite nanocomposite prepared via in situ coordinated polymerizationPOLYMER COMPOSITES, Issue 4 2002Junfeng Rong A polyethylene/palygorskite nano-composite (IPC composite) was prepared via an in-situ coordinated polymerization method, using TiCl4 supported on palygorskite fibers as catalyst and alkyl aluminum as co-catalyst. These composites were compared with those prepared by melt blending (MBC composites). It was found that in the IPC composites, nano-size fibers of palygorskite were uniformly dispersed in the polyethylene matrix. In contrast, in the MBC composites, the palygorskite was dispersed as large clusters of fibers. Regarding the mechanical properties of the IPCs, the tensile modulus increased and the elongation at break decreased with increasing fiber content, while the tensile strength passed through a maximum. The tensile strength and elongation at break were much smaller for the MBC composites. The final degree of crystallinity of the IPC composites decreased with increasing palygorskite content. Regarding the kinetics of crystallization, the ratio between the degree of crystallinity at a given time and the final one was a universal function of time. It was found that large amouns of gel were present in the IPC composites and much smaller amountes in the MBC composites. [source] Structural properties and mechanical behavior of injection molded composites of polypropylene and sisal fiberPOLYMER COMPOSITES, Issue 3 2002X. L. Xie Composites based on isotactic polypropylene (PP) and sisal fiber (SF) were prepared by melt mixing and injection molding. The melt mixing characteristics, thermal properties, morphology, crystalline structure, and mechanical behavior of the PP/SF composites were systematically investigated. The results show that the PP/SF composites can be melt mixed and injection molded under similar conditions as the PP homo-polymer. For the composites with low sisal fiber content, the fibers act as sites for the nucleation of PP spherulites, and accelerate the crystallization rate and enhance the degree of crystallinity of PP. On the other hand, when the sisal fiber content is high, the fibers hinder the molecular chain motion of PP, and retard the crystallization. The inclusion of sisal fiber induces the formation of ,-form PP crystals in the PP/SF composites and produces little change in the inter-planar spacing corresponding to the various diffraction peaks of PP. The apparent crystal size as indicated by the several diffraction peaks such as L(110),, L(040),, L(130), and L(300), of the , and ,-form crystals tend to increase in the PP/SF composites considerably. These results lead to the increase in the melting temperature of PP. Moreover, the stiffness of the PP/SF composites is improved by the addition of sisal fibers, but their tensile strength decreases because of the poor interfacial bonding. The PP/SF composites are toughened by the sisal fibers due to the formation of ,-form PP crystals and the pull-out of sisal fibers from the PP matrix, both factors retard crack growth. [source] Extrusion conditions and properties of vapor grown carbon fiber reinforced polypropylenePOLYMER COMPOSITES, Issue 5 2001Rex J. Kuriger Vapor grown carbon fiber (VGCF) is a new and inexpensive carbon fiber produced by vapor deposition of hydrocarbons on metal catalysts. The ability to fabricate VGCF reinforced thermoplastic composites by extrusion provides the potential to exploit VGCF into new commercial markets. This study investigates the extrusion conditions and properties of VGCF reinforced polypropylene. Extrusion was carried out using a Leistritz twin-screw extruder. Polypropylene reinforced with 0% to 12.5% volume fraction VGCF was extruded successfully at temperatures ranging from 215°C to 250°C. The extrusion pressure increased and the flow rate decreased as the percentage of fiber was increased. Increases in tensile strength and modulus were observed by the addition of VGCF. However, the void content of the composite samples increased with fiber content. [source] The influence of fiber surface modification on the mechanical properties of coir-polyester compositesPOLYMER COMPOSITES, Issue 4 2001J. Rout Coir, an important lignocellulosic fiber, can be incorporated in polymers like unsaturated polyester in different ways for achieving desired properties and texture. But its high level of moisture absorption, poor wettability and insufficient adhesion between untreated fiber and the polymer matrix lead to debonding with age. In order to improve the above qualities, adequate surface modification is required. In our present work, fiber surface modification was effected through dewaxing, alkali (5%) treatment, aqueous graft copolymerization of methyl methacrylate (MMA) onto 5% alkali treated coir for different extents using CuSO4 , NaIO4 combination as an initiator system and cyanoexhylation with a view to improve the mechanical performance of coir-polyester composites. Mechanical properties like tensile strength (PS), flexural strength (ES) and impact strength (IS) of the composites as a function of fiber loading and fiber surface modification have been evaluated. Composites containing z5 wt% of fiber (untreated) improved tensile and flexural strength by 30% and 27% respectively in comparison to neat polyester. The work of fracture (impact strength) of the composite with 25 wt% fiber content was found to be 967 J/m. The elongation at break of the composites exhibits an increase with the introduction of fiber, All types of surface modification result In improved mechanical properties of the composites. Significant improvement in mechanical strength was also observed for composites prepared from 5% PMMA grafted fiber. [source] Biocomposites based on Alfa fibers and starch-based biopolymerPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009R. Belhassen Abstract Biocomposite materials based on Alfa cellulose fibers (esparto grass plant) as reinforcing element and starch-based biopolymer matrix were prepared and characterized in terms of mechanical performance, thermal properties, and water absorbance behavior. The fibers and the matrix were first mixed in the melted state under mechanical shearing using a plastograph and the obtained composites were molded by injection process. The tensile mechanical analysis showed a linear increase of the composite flexural and tensile modulus upon increasing the fiber content, together with a sharp decrease of the elongation at break. The fibers, incorporation into the biopolymer matrix brings about an enhancement in the mechanical strength and the impact strength of the composite. Dynamic mechanical thermal analysis (DMTA) investigation showed two relaxations occurring at about ,30 and 35°C. The addition of Alfa fibers enhanced the storage modulus E, before and after T,, which is consistent with the reinforcing effect of Alfa cellulose fibers. Copyright © 2008 John Wiley & Sons, Ltd. [source] Thermal Sensor to Monitor Mechanical Properties in Polymer/Fiber Composite MoldingTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2002David Rouison Abstract Multi-layered samples of 1) continuous fiber axially aligned and 2) random oriented mat glass fiber composites were manually prepared for a fiber content ranging from zero to 20% (vol.). The uniaxially aligned samples displayed linear relations between both normalized elastic modulus and normalized thermal conductivity, and fiber content, for axially applied load and heat flux. For the random mat composite samples, similar results were obtained, with symmetry displayed in the plane of the mat. In both cases, measured axial thermal conductivity permits an evaluation of the axial elastic modulus. The Mathis surface probe used (US patent #5,795,064) is demonstrated as a non-intrusive indirect method of obtaining thermal conductivity for heat flux parallel (i.e. axial or transverse) to the plane of a sample. The method shows potential for use as an in-line monitoring device for the mechanical properties of molded composites. Des échantillons multicouches de composites (1) de fibres continues alignées dans le sens axial et (2) de fibres de verre en natte orientées aléatoirement, ont été préparés manuellement pour une teneur en fibre comprise entre 0 et 20 % (vol.). Pour les échantillons alignés dans le sens uniaxial, on montre l'existence de relations linéaires entre la teneur en fibre et le module élastique normalisé et entre la teneur en fibre et la conductivité thermique normalisée, pour une charge et un flux de chaleur appliqués dans le sens axial. Pour les échantillons de composite en natte aléatoire, des résultats similaires ont été obtenus, avec une symétrie observée dans le plan de la natte. Dans les deux cas, la conductivité thermique axiale mesurée permet une évaluation du module élastique axiale. On démontre que la sonde de surface Mathis utilisée (brevet US # 5,795,064) constitue une méthode indirecte non intrusive pour obtenir la conductivité thermique pour un flux de chaleur parallèle (c.-à-d. axial ou transversal) au plan de la surface de l'échantillon. La méthode montre du potentiel en tant que dispositif de surveillance en ligne pour les propriétés mécaniques des composites moulés. [source] Effects of high- and low-fiber diets on fecal fermentation and fecal microbial populations of captive chimpanzeesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2009Svetlana Ki, idayová Abstract We examined fiber fermentation capacity of captive chimpanzee fecal microflora from animals (n=2) eating low-fiber diets (LFDs; 14% neutral detergent fiber (NDF) and 5% of cellulose) and high-fiber diets (HFDs; 26% NDF and 15% of cellulose), using barley grain, meadow hay, wheat straw, and amorphous cellulose as substrates for in vitro gas production of feces. We also examined the effects of LFD or HFD on populations of eubacteria and archaea in chimpanzee feces. Fecal inoculum fermentation from the LFD animals resulted in a higher in vitro dry matter digestibility (IVDMD) and gas production than from the HFD animals. However, there was an interaction between different inocula and substrates on IVDMD, gas and methane production, and hydrogen recovery (P<0.001). On the other hand, HFD inoculum increased the production of total short-chain fatty acids (SCFAs), acetate, and propionate with all tested substrates. The effect of the interaction between the inoculum and substrate on total SCFAs was not observed. Changes in fermentation activities were associated with changes in bacterial populations. DGGE of bacterial DNA revealed shift in population of both archaeal and eubacterial communities. However, a much more complex eubacterial population structure represented by many bands was observed compared with the less variable archaeal population in both diets. Some archaeal bands were related to the uncultured archaea from gastrointestinal tracts of homeothermic animals. Genomic DNA in the dominant eubacterial band in the HFD inoculum was confirmed to be closely related to DNA from Eubacterium biforme. Interestingly, the predominant band in the LFD inoculum represented DNA of probably new or yet-to-be-sequenced species belonging to mycoplasms. Collectively, our results indicated that fecal microbial populations of the captive chimpanzees are not capable of extensive fiber fermentation; however, there was a positive effect of fiber content on SCFA production. Am. J. Primatol. 71:548,557, 2009. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||||||||