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A sandwich structure of carbon-epoxy laminate with graphene nanoplatelets is used for increasing the AC conductivity, dielectric constant and sensitivity towards moisture. The Quasi Fickian distribution of moisture absorption of epoxy is retained with the inclusion of carbon fibers and graphene nanoplatelets of 1 weight percent. The effect of relative humidity (RH) over a range of 30–90% on AC conductivity and capacitance has been investigated. Use of carbon fibers with graphene nanoplatelets significantly enhances the electrical conductivity and dielectric constant as compared to carbon-epoxy laminate without graphene nanoplatelets. The two parameters reveal linear dependence on humidity in the low frequency range of 100–1000 Hz. The AC conductivity increases at the rate of 2 nSm−1/% RH in laminate with carbon fiber and it increases to 50 nSm−1/%RH with the incorporation of graphene nanoplatelets. The increase in AC conductivity from 100 Hz to 1000 Hz is in the range of 0.1 to 0.2 μS/m with carbon fibers and it increases from 1 to 4 μS/m with the inclusion of graphenenanoplatelets. Increase is AC conductivity from 1 kHz to 10 MHz is by five orders of magnitude, with a steep increase around 5 MHz in both laminates. The incorporation of graphenenanoplatelets helps to increase the dielectric constant by 2.4–2.8 times as compared to epoxy with carbon fiber. The swelling in the laminates estimated after 96 h of exposure to 90% RH is observed to be less than 0.05%. The use of graphenenanoplatelets improves moisture sensitivity of the carbon-epoxy laminate.

The goal of the research was to assess the recycling potential of waste high-density polyethylene (HDPE) films taken as reinforcement with natural fibers to fabricate decorative tiles with improved mechanical properties. Initially, the density of the composite was determined. Further, hardness, quasi-mechanical and impact properties were evaluated for the HDPE/natural fiber composite samples by testing the composites tensile, flexural loads and impact. In addition, to evaluate the thermal characteristics of the composite, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) study were performed. Water absorption and sound absorption properties were determined for industry specific applications. Scanning Electron Microscopic analysis (SEM) was performed for analyzing the microstructure and also HDPE matrix and natural fibers bonding exists in the composite. The findings confirmed that adding natural fibers to the HDPE matrix impressively increased both tensile and flexural strengths by up to 25%. The impact strength was also enhanced by up to 38%, whereas the hardness and density values remained relatively unchanged. Improved interfacial bonding between the HDPE matrix and natural fibers had been identified by SEM analysis, which was a factor in the composite material's enhanced mechanical characteristics. These findings suggest that waste HDPE films/natural fibers composite can be effectively recycled to fabricate decorative tiles with improved mechanical properties, thereby offering a sustainable and eco-friendly alternative to traditional decorative tile materials.

This work addresses manufacture, testing and simulation of foot valve lever (FVL) for monoblock pump industry, using a cost-effective casting design process. The impact of different types of sands, such as air-set, dry and sodium silicate as well as gating designs, namely H-, U- and O-type, were studied with respect to surface roughness and porosity. The mold pattern was produced using additive manufacturing (AM) technology. Both experimental and numerical investigations were performed on the temperature distribution of molten metal at random locations for the different gating configurations or designs, considering mold filling and solidification. It was evident from the experimental investigation that contribution of air-set sand and O-type gating architecture showed limited consistency effects. Importantly, gating architecture was the most influential parameter to determine all specified quality outcomes, independent of sand mold. An order of O

Fibre reinforced polymer (FRP) hybrid composites builds vertically due to the achievement of custom-made properties with lightweight. However, these materials have finding limitations in exceptional circumstances due to the unpredicted sustainability. Hence, it is necessary to create the database for the durable and sustainable low-density FRP hybrid composites with the support of significant experimental investigations. This review paper is mainly covers durability studies of various FRP hybrid composites under different environmental conditions. The thermal ageing, hydrothermal ageing, sea water, acid and alkali environment, ultraviolet radiation and stress cycle effects were extensively discussed with suitable scientific evidence in this work. Further, most of the FRP composites are rapidly degraded by underwater conditions at high temperatures. The failure mechanisms such as delamination, degradation of fibre and matrix, poor interfacial adhesion, matrix surface cracking, etc. are found to be dominant in the FRP composites under the hydrothermal and acid environment conditions also covered. The combination of natural/synthetic hybrid composites and addition of some nano fillers enhance the durability performance of hybrid composites significantly. However, ageing properties of hybrid polymer composites in different environment conditions need to study for various applications. The review process revealed that the life cycles of hybrid FRP composites mainly affected by stress cycle based on continuous usage.