Environmental impact assessment (EIA) is a policy tool used for evaluating a project proposal from physical and socioeconomic environmental perspectives. Its aim is to reduce the impact of development on environment, hence, ensuring environmental sustainability. It is mandatory to submit an Environmental Impact Statement before starting a mega project as required by Environmental Protection Act of 1997 and Environmental Policy of Pakistan. Public consultation plays a key role in an EIA system, identifying the likely aspects and impacts of a development activity. This aspect has been ignored in effective enactment of environmental legislation in Pakistan. Sufficient legislative instruments are there to support EIA system in the country but the agencies responsible for the enforcement of environmental regulations have failed to do so. The current research gives an insight into the actual status of EIA system in Pakistan along with the feedback of EIA specialists and university teachers of the concerned departments. A new index has been devised on the basis of questionnaire response to work out the overall performance of EIA system in Pakistan or any other country. The weaknesses and deficiencies of each EIA stage have been worked out for Pakistan and elaborated with the help of the controversial Zero point Interchange Project in the capital city of Pakistan.
Plant-mediated nanoparticles are gaining popularity due to biologically active secondary metabolites that aid in green synthesis. This study describes a simple, environmentally friendly, dependable, and cost-effective production of silver nanoparticles utilizing Cucumis sativus and Aloe vera aqueous leaf extracts. The aqueous leaf extracts of Cucumis sativus and Aloe vera , which worked as a reducing and capping agent, were used to biosynthesize silver nanoparticles (AgNPs). The formation of surface plasmon resonance peaks at 403 and 405 nm corresponds to the formation of colloidal Ag nanoparticles. Similarly, the Bragg reflection peaks in X-ray diffraction patterns observed at 2θ values of 38.01°, 43.98°, 64.24°, and 77.12° representing the planes of [111], [200], [220], and [311] correspond to the face-centered cubic crystal structure of silver nanoparticles. Fourier transform infrared spectroscopy confirms that bioactive chemicals are responsible for the capping of biogenic silver nanoparticles. The size, structure, and morphology of AgNPs with diameters ranging from 8 to 15 nm were examined using transmission electron microscopy. Water contamination by azo dyes and nitrophenols is becoming a more significant threat every day. The catalytic breakdown of organic azo dye methyl orange (MO) and the conversion of para -nitrophenol (PNP) into para -aminophenol using sodium borohydride was evaluated using the prepared biogenic nanoparticles. Our nanoparticles showed excellent reduction ability against PNP and MO with rate constants of 1.51 × 10 –3 and 6.03 × 10 –4 s –1 , respectively. The antibacterial activity of the nanomaterials was also tested against four bacteria: Staphylococcus aureus , Klebsiella pneumoniae , Enterobacter , and Streptococcus pneumoniae . These biogenic AgNPs displayed effective catalytic and antibacterial characteristics by reducing MO and PNP and decreasing bacterial growth.
Composite structures are extensively used in various fields ranging from, but not limited to marine, aerospace, automotive, agricultural and industrial equipment due to their unique and excellent properties like weight associated with density. On an increase in their applications, it also requires special attention to manufacture and process the composites to acquire the high level of stability. Most critical defect in composite structures that have attracted many researchers is delamination. Delamination in composite structures are inevitable during service period. Present work is focused on investigating the effect of presence of delamination in the carbon fiber reinforced composite plate using finite element solver software, ANSYS. Present analysis will focus to find the effect of delamination size, boundary constraints and layups on the natural frequency of carbon fiber composite plate. Analytical results were also analyzed using MATLAB environment. Governing equations were derived using Rayleigh-Ritz method. The natural frequency reduced on an increase in delamination size and it is high in clamped-clamped boundary conditions rather than simply supported constraints. The finite element results are then compared with analytical results for clamped-clamped boundary conditions and found in close agreement.
Radomes are usually constructed from sandwich structures made of materials which usually have a low dielectric constant so that they do not interfere with electromagnetic waves. Performance of the antenna is increased by the appropriate assortment of materials enabling it to survive under marine applications, and it depends on composite strength-to-weight ratio, stiffness, and resistance to corrosion. The design of a sandwich core submarine radome greatly depends on the material system, number of layers, orientation angles, and thickness of the core material. In this paper, a conceptual design study for a sandwich core submarine radome is carried out with the help of finite element analysis (FEA) using two unidirectional composite materials—glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP)—as a skin material and six different core materials. Conceptual designs are obtained based on constraints on the composite materials’ failure, buckling, and strength. The thickness of the core is reduced under constraints on material and buckling strength. Finite element analysis software ANSYS WORKBENCH is used to carry out all the simulations.
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