Water Purification and Disinfection by Using Solar Energy: Towards Green Energy Challenge

The aim of this work was to design a solar water treatment plant for household purpose. Water purification is the process of eradicating detrimental chemicals, biological poisons, suspended solids and gases from contaminated water. In this work we have reported an investigation of compact filter which is cost effective for developing countries and ease of maintenance. We have arranged a solar water disinfection system that improves the microbiological quality of drinking water at household level. We get 14 L pure water and 16 ml water vapour within 240 min by using filtration method. From our work we get hot water up to 49°C. The efficiency of the system at sunny days and cloudy days are 18.23% and 18.13% respectively. This simple solar hybrid system helps to remove turbidity as well as chemical and pathogenic contaminants from water sources in the most affordable, and expedient manner possibly

"A Non-Iterative Formulation for 2D Optical Waveguide Discontinuity Problems Based On Padé Approximants"

In this letter, we propose a simple non-iterative formulation for the analysis of optical waveguide discontinuity problems. The formulation, which is based on rotated branch cut Padé approximation scheme, is both accurate and efficient. It is computationally fast due to its non-iterative nature. The effectiveness of the proposed approach is demonstrated by modeling an optical waveguide air facet. Calculations show good agreement with previously published results

Changes in Color and Physiological Components of The Postharvest Mango (Mangifera indica L.) Influenced by Different Levels of GA3

Abstract - This experiment consisted of two popular mango varieties in Bangladesh (viz., Langra and Khirshapat) and four different levels of Gibberellic acid (GA3) solution, namely control, 100, 200 and 400 ppm. The two factors experiment was assigned in randomized complete block design with tree replicates. Data obtained from various biochemical analyses in terms of physicochemical properties and shelf life of postharvest mango, were recorded and statistically analyzed for comparison among the mean values using DMRT and LSD. The results of the experiments exhibited that only the single effect of varieties was found to be significant in most of the parameters studied. Variety the Langra performed better in accumulating higher quantity of dry matter, ash, vitamin c content in all four experiments over Khirshapat. On the other hand, the Khirshapat showed better performance in achieving higher quantity of moisture, progressively lost physiological weight as well as extended shelf life and delayed skin color changes than Langra at all the storage duration. Keywords: Postharvest mango; Gibberellic acid; physiological components

A Novel Derivatization Ultraviolet Spectrophotometric Method for the Determination of Amlodipine Besylate Using Benzoyl Chloride

The present research work aims to develop a novel ultraviolet UV spectrophotometric method for the determination of Amlodipine Besylate using Benzoyl Chloride as a derivatizing agent, which is simple, rapid, sensitive, selective, and accurate method for the spectrophotometric determination of Amlodipine Besylate in powder form.  Synthesis is based upon the Schotten Baumann Reaction. In this method, derivatization of aliphatic amine group of Amlodipine Besylate carried out with benzoyl chloride and aqueous sodium hydroxide (NaOH).The λmax was found to be 237 and 226nm for assay of Amlodipine Besylate and synthesised product respectively. The linearity was found in concentration range of 1-10 μg/ml. The correlation coefficient (r2)was found 0.9985. The regression equation, intercept (a) and slope (b) was found as Y=0.0762x - 0.0077, 0.0077 and 0.0762 respectively. Method was developed and validated as per ICH guidelines for linearity, accuracy, precision, LOD, LOQ, interday and intraday. The LOD and LOQ for estimation of Amlodipine besylate were found as 0.2367, 0.7178 respectively. Recovery of Amlodipine besylate was found to be 93.30%.The proposed method is found to be simple, rapid, selective and highly sensitive than most of the Spectrophotometric methods available in literature. Keywords: Derivatization, Ultraviolet spectrophotometry, Amlodipine besylate, Validation, Synthesis

Thermal, physical properties and flammability of silane treated kenaf/ pineapple leaf fibres phenolic hybrid composites

Silane treated pineapple leaf fibre (PALF) and kenaf fibre were analyzed by Thermogravimetric analysis (TGA) that indicated the treated hybrid composite showed better thermal stability as compared to untreated hybrid composites. Dynamic mechanical analysis was carried out to evaluate the storage modulus (E′), loss modulus (E″), and tan delta as a function of temperature. Storage modulus of treated hybrid composites displayed highest storage and loss modulus as in comparison of untreated hybrid composites. The peak heights of tan α were highest in treated hybrid composites. Cole-Cole analysis was also carried out to understand the phase behaviour of the composite samples. Thermal mechanical analysis was used to study mechanical stability of hybrid composites in the presence of temperature. The effect of different fibre ratios in hybridization on density, void content, water absorption (WA), thickness swelling (TS) of PALF/KF hybrid composites were also analyzed. Treated hybrid composites were not very affective to improve the flammability of PALF/KF hybrid composites. The overall results showed that treated PALF/KF/phenolic hybrid composites improved the thermal and dynamic mechanical properties over untreated PALF/KF hybrid composites

A new estimate of carbon for Bangladesh forest ecosystems with their spatial distribution and REDD+ implications

In tropical developing countries, reducing emissions from deforestation and forest degradation (REDD+) is becoming an important mechanism for conserving forests and protecting biodiversity. A key prerequisite for any successful REDD+ project, however, is obtaining baseline estimates of carbon in forest ecosystems. Using available published data, we provide here a new and more reliable estimate of carbon in Bangladesh forest ecosystems, along with their geo-spatial distribution. Our study reveals great variability in carbon density in different forests and higher carbon stock in the mangrove ecosystems, followed by in hill forests and in inland Sal (Shorea robusta) forests in the country. Due to its coverage, degraded nature, and diverse stakeholder engagement, the hill forests of Bangladesh can be used to obtain maximum REDD+ benefits. Further research on carbon and biodiversity in under-represented forest ecosystems using a commonly accepted protocol is essential for the establishment of successful REDD+ projects and for the protection of the country’s degraded forests and for addressing declining levels of biodiversity

Trapped lipopolysaccharide and LptD intermediates reveal lipopolysaccharide translocation steps across the Escherichia coli outer membrane

Lipopolysaccharide (LPS) is a main component of the outer membrane of Gram-negative bacteria, which is essential for the vitality of most Gram-negative bacteria and plays a critical role for drug resistance. LptD/E complex forms a N-terminal LPS transport slide, a hydrophobic intramembrane hole and the hydrophilic channel of the barrel, for LPS transport, lipid A insertion and core oligosaccharide and O-antigen polysaccharide translocation, respectively. However, there is no direct evidence to confirm that LptD/E transports LPS from the periplasm to the external leaflet of the outer membrane. By replacing LptD residues with an unnatural amino acid p-benzoyl-L-phenyalanine (pBPA) and UV-photo-cross-linking in E.coli, the translocon and LPS intermediates were obtained at the N-terminal domain, the intramembrane hole, the lumenal gate, the lumen of LptD channel, and the extracellular loop 1 and 4, providing the first direct evidence and “snapshots” to reveal LPS translocation steps across the outer membrane

Effect of pipe size on acetylene flame propagation in a closed straight pipe

The understanding of flame propagation mechanism in a tube or pipe as a function of scale is needed to describe explosion severity. Acetylene is an explosively unstable gas and will lead to a violent explosion when ignited. To achieve the goal, an experimental study of premixed acetylene/air mixture at stoichiometry concentration was carried out in a closed straight pipe with different sizes of L/D (ratio of length to diameter) to examine the flame propagation mechanism. Pipes with L/D=40 and 51 were used. From the results, it was found that the smaller pipe with L/D=40 enhanced the explosion severity by a factor of 1.4 as compared to that of the bigger pipe with L/D=51. The compression effect at the end of the pipe plays an important role to attenuate the burning rate, leading to higher flame speeds and hence, increases the overpressure. In the case of L/D=40, the compression effect is more severe due to the larger expansion ratio, and this phenomenon would decrease the quenching effect and subsequently promote flame acceleration. Fast flame speeds of up to 600 m/s were measured in the smaller pipe during explosion development. From the results, it can be seen that the compression effect plays a major role in contributing to the higher burning rate and affects the overall explosion and flame speed development. Furthermore, the compression effect is more severe in the smaller pipe that leads to the detonation-like event. This mechanism and data are useful to design a safety device to minimise explosion severity