Coconut coir fibre and synthetic string fibre were used as reinforcements in plaster of Paris (POP) for ceiling application in this research. Coconut coir fibre, being fairly strong and stiff as well as cheap and plentiful with low energy demand during manufacture was used alongside synthetic fibre in view that both can serve as material for ceiling board. The fibres, whose mass fraction were the variables in this work, were cut down into smaller sizes and mixed with cement and water. The resulting slurry was then poured into rectangular moulds and allowed to cure. Flexural, Impact and Hardness tests were carried out on the various samples. From the analysis of results for the mechanical properties of coconut coir and synthetic fibres reinforced POP based composites, it was discovered that both Coconut coir and synthetic fibre show promising performances with respect to the properties considered.
Aim: This study investigated the molecular characterization of hydrocarbon-utilizing rhizobacteria isolates from hydrocarbon-impacted mangrove soil from K-Dere Gokana and Gio Tai, Ogoni land, Nigeria.
Study Design: Cross-sectional study.
Place and Duration of Study: K-Dere Gokana and Gio Tai, Ogoni land, Nigeria, between June 2019 and June 2020.
Methodology: Hydrocarbon-utilizing bacteria were isolated from the rhizosphere of hydrocarbon-impacted mangrove soil. Baseline physicochemical and microbiological characteristics of the rhizosphere soil from the contaminated sites were determined. Hydrocarbon utilization was determined turbidometrically using a spectrophotometer and by growth on Bushnell, Haas agar supplemented with 1% crude oil.
Results: Analysis of the rhizosphere soil revealed that the site was contaminated with crude oil with a TPH value of 547.62±40.15 mg/kg. Based on phylogenetic analysis of these 16S rRNA genes the isolates were classified as Bacillus thuringiensis SA2-1; Bacillus velezensis SA11-2; Morganella morganii SA4-3; Serratia ureilytica SB1-4; Serratia marcescens SB5-5 and Serratia nematodiphila SB16-6. The sequences have been deposited under the accession numbers MN631244.1-MN631249.1. These bacteria all demonstrated efficient hydrocarbon utilization in Bushnell medium with 1% crude as the sole carbon source. These bacteria are well documented putative hydrocarbon utilizers.
Conclusion: This study has demonstrated that hydrocarbon utilization from different genera was associated with the rhizosphere of hydrocarbon-impacted mangroves in Gio and K-Dere.
This paper reports on the compressive strength and flexural tensile behavior of recycled polyethylene fibre reinforced concrete. Twelve concrete cubes of dimension 150 mm ×150 mm × 150 mm containing 0%, 0.25%, 0.50% and 1.0% of polyethylene fibres were cast and tested per BS 1881-part 116: 1983 to determine the compressive strength. Twelve concrete prisms measuring 100 mm×100 mm×300 mm containing 0%, 0.25%, 0.50% and 1.0% of polyethylene fibres were also cast and tested under a center-point loading system using an Avery Denison universal testing machine per the American Society for Testing and Materials, ASTM C78-2009 to investigate the flexural behavior of the polyethylene fibre concrete. Results of the tests showed that, the compressive strength fell from an average of 33.07 N/mm2 for the plain concrete specimen to an average of 17.74 N/mm2 for the 1.0% fibre concrete specimen. The drop in average compressive strength is 22% for the 0.25% fibre concrete, 36% for the 0.5% fibre concrete, and 46% for the 1.0% fibre concrete specimen. These drops in compressive strength of the polyethylene fibre concrete are quite significant compared to the plain concrete. The modulus of rupture which is an indication of the flexural tensile strength of the concrete however increased from 6.56 N/mm2 for the plain concrete to 8.32 N/mm2 for the 1.0% fibre concrete. The percentage increase is 3% for the 0.25% fibre concrete, 14% for the 0.5% fibre concrete, and 27% for the 1.0% fibre concrete specimen. The polyethylene fibres therefore have a generally positive effect on the flexural strength of concrete.
This review surveys the research work published in the field of nanoclay (montmorillonite, MMT)-filled composites with particular reference to the effect of nanoclay (NC) introduction on the tensile, flexural, impact and compressive strength of nanocomposites. The matrix most frequently used in NC-filled composites is epoxy, although other thermosetting and thermoplastic polymer materials have also been used. To make MMT more compatible with these matrices, they have been often subjected to organophilic modification with the use of organic cations, therefore indicated as organo-montmorillonites (OMMT). NC-filled composites are also fabricated with the most common reinforcements, such as carbon, glass, Kevlar and basalt, and more recently also biomatrices with natural fibers have also been proposed. A few studies on ceramic matrices have also been reported. The review concentrates on the maximum level of improvement obtained in the referred studies by the introduction of NC in the bare matrix or in the fiber reinforced composites, with respect to tensile, flexural, impact and compression strength, with the idea of disposing a database in comparing the best values obtained by nanoclay introduction against the benchmark composite.
Quantum dots (QDs) provide a powerful material to engineer various optoelectronics devices as well as it provides many opportunities in the biomedical field. QDs have received a great attention due to their significant properties. QDs are one of the foremost nanotechnologies to be incorporated with the biological sciences and are extensively projected helpful for application in a number of profitable consumer and clinical products. They exhibit unique luminescence characteristics and electronic properties such as wide and continuous absorption spectra, narrow emission spectra, and high light stability. In this review paper we will focus on synthesis method, characterization techniques for quantum dots and biomedical applications of silver sulphide (Ag2S) QDs as they are less toxic as compare than CdSe, PbSe, CdS quantum dots. Silver sulphide quantum dots are widely used in bio medical applications.
