Influence of Resin Viscosity on Physical Properties of a Composite Shell Wound on a Low Density Material Mandrel

This study is made to improve the structural performance of composite shells/ vessels meant for aerospace vehicles. The effect of resin viscosity on the physical properties of carbon/ epoxy composite shell wound on polyurethane (PU) foam-based mandrel is studied and presented in this paper. Cylindrical shells were manufactured through the filament winding process at different resin viscosities. The physical properties of the composite shell are found to be improved significantly with a reduction in resin viscosity. Resin pick-up in impregnated fibers is found to be lower by 4.5 %, whereas mass and thickness of the shells are recorded to be lower by 3 % and 5.4 % respectively at resin viscosity range of 600 -760 mPa.s compared to the viscosity range of 1380 – 2080 mPa.s. Fiber volume fraction and density of composite shell are found to be higher by 6.3 % and 2.8 % at the same resin viscosity range. This trend reverses/stabilizes after further heating and corresponding lowered resin viscosity. Experiment and their result indicate an optimal viscosity range of 600 – 760 mPa.s. for filament winding of efficient carbon/ epoxy composite shel

Effect of Aviation Turbine Fuel Exposure on Interlaminar and Inplane Shear Properties of Glass Fiber Reinforced Epoxy Composite

This study investigated the effect of aviation turbine fuel exposure on interlaminar and in-plane shear properties of E-glass/epoxy composite. The two types of test specimens, namely bare and resin-coated specimens with varying thicknesses as per the ASTM standard, were made out of E-glass/epoxy composite to evaluate their interlaminar and in-plane shear properties. These all types of specimens were immersed inside the aviation turbine fuel for two months and then afterward their effect on the reduction of mechanical properties like interlaminar and in-plane shear tests properties were experimentally investigated. Test results show that ATF fuel exposure has reduced the interlaminar shear strength by 10.04 %, 7.83 %, and 6.01 % for bare, with 0.1 mm and 0.2 mm resin coating, respectively. Similarly, in-plane shear strength was reduced by 14.75 %, 11.22 %, and 7.52 % for bare, with 0.1 mm and 0.2 mm resin coating, respectively, and in-plane shear modulus was reduced by 10.87 %, 8.94 %, and 6.52 % for bare, with 0.1 mm and 0.2 mm resin coating conditions as compared to as-received (without ATF exposure) specimens.SEM micrographs and results too showed that properties were reduced and indicated that the glass/epoxycomposite was resistive to fuel ingression. It was observed that bare specimens exhibited a reduction in shearproperties due to ATF ingression to the polymeric network and induced internal stresses, which not only degraded the matrix and fiber-matrix adherence but created micro-cracks too in the resin at interfaces. Resin-coated specimens limit fuel ingression, which has led to a reduction in properties

Impact of varieties and organic nutrient sources on productivity, soil carbon stocks and energetics of rice-ratoon system in Eastern Himalayas of India

Cultivation of rice (Oryza sativa L.) varieties having ratooning potential under adequate organic nutrient sources (ONSs) could improve system productivity, soil organic carbon (SOC) stock and energy use efficiency in the eastern Indian Himalayas. A 6-year study was conducted to evaluate the impact of four varieties (Shahsarang-1, Lampnah, IR-64 and Krishna Hamsha) under five ONSs [pig manure (PM), farmyard manure (FYM), vermicompost (VC), in situ paddy straw (PS) recycling and farmers’ practice] on productivity, soil health and energetics of a rice-ratoon system in a mid-hill (950 m asl) subtropical climate. Organic manures were applied on an N-equivalent basis. The 6-year average grain yield of main rice was significantly highest for Shahsarang-1 (4.40 Mg ha−1) followed by IR-64. Shahsarang-1 (2.58 Mg ha−1) and IR 64 also produced higher ratoon crop yields, leading to higher total annual productivity (main + ratoon crops) than other varieties. Rice grown with PM produced the highest average rice productivity of main crop, followed by FYM. The highest total N, P and K uptake by the rice was obtained under PM followed by FYM. After six cropping cycles, the maximum SOC stock and available N and P were observed under PM, whereas available K was highest under PS recycling. The highest gross energy output, net energy and energy intensity were registered with PM, whereas energy use efficiency and energy productivity were the highest under control. Thus, cultivation of either Shahsarang-1 or IR-64 using PM/FYM is appropriate for enhancing productivity, soil health and conservation of energy in the study region and similar eco-regions elsewhere

Impact of fodder grasses and organic amendments on productivity and soil and crop quality in a subtropical region of eastern Himalayas, India

•Four fodder crops under 3-sources of nutrients compared in a 3-year study.•Hybrid napier recorded the highest (28.1Mgha−1) average dry fodder yield.•Mean dry fodder yields under organic was 27.5% higher than inorganic fertilizer•Perennial forages improved soil quality and SOC stocks.•Organic sources of fertilizers improved SOC stock by ∼10% after 3-years. Agriculture in the Eastern Indian Himalayas is characterized by fragility and marginality with about 77% of the geographical area under hills and degraded plateau. Thus, field experiments were conducted for three consecutive years during 2008–2011 to assess the impact of perennial fodder grasses and sources of nutrient supply on productivity and quality of soil and fodder under terrace conditions in a subtropical degraded hill soil of Meghalaya, India (980m above sea level). The treatment consisted of four fodder crops and three sources of nutrients. Fodder crops were broom grass (Thysanolaena maxima), congosignal grass (Brachieria rosenesis), hybrid napier (Pennisetum typhoides x P. purpureum) and guinea grass (Panicum maximum). Three sources of nutrient supply were organic, inorganic and control (inherent soil fertility conditions). Farmyard manure (FYM) was used as organic source of nutrient supply on N equivalent basis and P nutrition was supplemented through rock-phosphate. Fertilizer urea, single super phosphate and muriate of potash were used as inorganic source of nutrients. The dry fodder yield increased in each successive year and three year average dry fodder yield was significantly higher with hybrid napier (28.1Mgha−1) than other grasses. Among nutrient sources, the average dry fodder yield under organic amendment (22.9Mgha−1) was 27.5 and 64.4% higher than that under inorganic fertilizer (17.9Mgha−1) and control (13.9Mgha−1), respectively. Crude fibre (35.9%) and lignin (7.02%) concentrations were the maximum in hybrid napier whereas, cellulose (39.1%) was the highest in congosignal grass. On the contrary, crude protein concentration was the maximum in broom grass (8.27%), and it was at par with that in hybrid napier. The available N, P, K and soil organic carbon (SOC) contents were significantly higher (P=0.05) under organic compared to those under other nutrient sources. The SOC concentration (17.2gkg−1) and stock (32.2Mgha−1) after three years under organic treatment was 5.3 and 2.1% and 13.3 and 8.1% higher than that recorded under inorganic and control, respectively. The study indicated suitability of fodder grasses and organic amendments in improving quality of marginal degraded hill soils