Historical Analysis of Rationalizing South-West Coastal Polders of Bangladesh

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Computational investigation of an unsteady non-Newtonian and non-isothermal fluid between coaxial contracting channels: A PCM approach

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Comparison between caudal epidural block and popliteal nerve block for postoperative analgesia in children undergoing foot surgery: a randomized controlled trial

Background: Pain following surgery in children cause discomfort, restlessness and agitation in the postoperative period which may result in an increased incidence of nausea, vomiting and maladaptive behavioural changes. Regional anaesthesia is commonly used as an adjunct to general anaesthesia for perioperative analgesia in children as part of a multimodal approach of pain relief. This study is to compare between caudal epidural block and popliteal nerve block for postoperative analgesia in children undergoing foot surgery.Methods: A prospective randomized single blind study was carried out on 30 children aged 1-12 years of either sex undergoing foot surgery. Patients were randomly assigned into caudal epidural block group and Popliteal nerve block group, 15 children each. Both groups receive 1 ml/kg of 0.25% bupivacaine. Foot surgery was carried out under general anesthesia along with regional block for all children. After completion of surgery, children were shifted to PACU and HR, BP, SPO2 were monitored. Patient was discharged from PACU after CHEOPS (1-5 years) or VAS (6-12 years) <4. Parental satisfaction, sedation score, PONV, and any other side effects were recorded.Results: Demographic data and baseline vital signs were comparable between two groups. Statistically significant difference (p=0.025) in number of attempts in giving block in group A (1.20±0.41) than group B (1.80±0.86). The mean postoperative pain scores, CHEOPS and VAS were comparable in both groups.Conclusions: Both caudal epidural block and popliteal nerve block provides comparable and adequate analgesia in children undergoing elective foot surgery

Hydrochemistry, water quality and land use signatures in an ephemeral tidal river : implications in water management in the southwestern coastal region of Bangladesh

Despite its complexity and importance in managing water resources in populous deltas, especially in tidal areas, literatures on tidal rivers and their land use linkage in connection to water quality and pollution are rare. Such information is of prior need for Integrated Water Resource Management in water scarce and climate change vulnerable regions, such as the southwestern coast of Bangladesh. Using water quality indices and multivariate analysis, we present here the land use signatures of a dying tidal river due to anthropogenic perturbation. Correlation matrix, hierarchical cluster analysis, factor analysis, and bio-geo-chemical fingerprints were used to quantify the hydro-chemical and anthropogenic processes and identify factors influencing the ionic concentrations. The results show remarkable spatial and temporal variations (p <0.05) in water quality parameters. The lowest solute concentrations are observed at the mid reach of the stream where the agricultural and urban wastewater mix. Agricultural sites show higher concentration of DO, Na+ and K+ reflecting the effects of tidal spill-over and shrimp wastewater effluents nearby. Higher level of Salinity, EC, Cl-, HCO3 (-), NO3 (-), PO4 (3-) and TSS characterize the urban sites indicating a signature of land use dominated by direct discharge of household organic waste into the waters. The spatial variation in overall water quality suggests a periodic enhancement of quality especially for irrigation and non-drinking purposes during monsoon and post-monsoon, indicating significant influence of amount of rainfall in the basin. We recommend that, given the recent trend of increasing precipitation and ground water table decrease, such dying tidal river basins may serve as excellent surface water reservoir to supplement quality water supply to the region.Peer reviewe

Comparative analysis of UWB balance Antipodal Vivaldi Antenna for array configuration

In this paper, an Ultra-wideband Balance Antipodal Vivaldi Antenna in planar and h-plane array configuration is presented. The comparison of four elements of BAVA array in both planes has been observed. Each element of an antenna printed on the glass-reinforced epoxy laminate material (FR4) with a thickness of 1.5mm and relative permittivity of 4.3. The dimension of every single element is 60.75mm x 66mm approximately. The array elements of both planes almost cover the whole UWB frequency range with the reflection coefficient of -10dB. Based on the simulation results, the array elements in planar configuration showing good reflection and works well at 3.2GHz frequency while the configuration in h-plane the array elements works well at 7GHz of frequency. In planar configuration, the operating frequency of antenna elements is shifting as a result of the distance between inter elements which intensification in wavelength. The array elements in h-plane produce more gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The antenna design and optimization development are verified using CST simulation software

Design and parametric evaluation of UWB antenna for array arrangement

This paper has introduced the concept of UWB antenna in array arrangements. The four elements of Balance Antipodal Vivaldi Antenna (BAVA) has been used for planar and H-plane array configuration in this research. Each single element of BAVA Antenna is printed on the glass-reinforced epoxy laminate material (FR4) along an overall thickness of 1.57mm and εr=4.3 respectively. The optimized measurement of each particular element is 60.75mm x 66mm approximatel. Further the parametric evaluation of four BAVA elements in different planes has been observed in this paper. The placement of array elements has almost coverd entire UWB frequency range and appropriate reflection coefficient which is better than -10dB has been established in both combinations. According to simulation results, the array elements in planar arrangement presenting a suitable reflection and works well at 3.2GHz frequency while the arrangement in H-plane the array elements works well at 7GHz of frequency. In planar arrangement, the operating frequency of antenna elements is shifting as results of the distance among inter elements which increase in wavelength. In H-plane arrangement an antenna elements generate additional gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The CSTMWS simulation software has been used for antenna structural design and parametric verification

UWB antenna based time-domain approach for through the walls gap estimation

This paper has introduced a novel experimental system adopted a time domain approach for estimating through wall distance and recognizes buried objects behind the wall. The designed and fabricated balanced antipodal Vivaldi antenna (BAVA) has been used for the development of UWB system. The working mechanism of an intended detection system based on time domain reflectometry (TDR) and ground-penetrating radar (GPR). A miniature pulse in the UWB range is generated by the vector network analyzer (VNA) to irradiate a barrier made of two walls separated by airgap between them. The signal radiations reflect partially from the front wall while remaining goes through for getting reflected from the rear wall. The VNA is used for measuring the time interval passed between the instant when an incident signal irradiates the first wall and the instant when the incident signal gets reflected from the rear wall. The investigational process of a system is carried out by UWB antenna probe. The detected information is attained using the values of reflection coefficient (S 11 ) represented in time domain measurements. Experimental results have been proved the ability to detect wall gap as well as the width estimation between two walls with high accuracy. The maximum percentage error has been found to not exceeding 4.5% in the worst condition

Biochar research advancement in Bangladesh: challenges and opportunities of biochar in improving soil health

Globally, biochar research and its application for soil improvement have attracted the interest of many researchers, primarily environmental and soil scientists, in the last decade. But, a limited number of biochar research studies have been conducted in Bangladesh. Therefore, a comprehensive study on biochar research is necessary to find out the scope and opportunities of biochar application in the soils of Bangladesh. Generally, biochar can improve the physical, chemical, and biological properties of soils. It also has a significant role in greenhouse gas emissions. The contaminated soils can also be remediated through the judicious application of biochar. In Bangladesh, biochar application enhanced soil pH, organic matter, phosphorus availability, and agricultural production while decreasing soil acidification, microbial activity, and heavy metals mobility. Besides that, there were both positive and negative findings regarding nitrogen availability, greenhouse gas emissions, and heavy metal accumulation. However, this review includes the selection of feedstock, the advancement of pyrolysis technology, the characterization of biochar, and the agronomic and environmental benefits of biochar use. This paper also reviews biochar study and application activities in Bangladesh over the last decade. Further research directions have been suggested to ensure the beneficial and safe application of biochar to agricultural property

Production, optimization, and physicochemical characterization of biodiesel from seed oil of indigenously grown Jatropha curcas

With the growing demand for vegetable oils, alternative non-edible feedstocks like Jatropha curcas seed oil have gained interest for biodiesel production. The study aimed to comprehensively evaluate the physicochemical properties and biodiesel production potential of locally produced J. curcas seeds in Pakistan. Two different approaches were applied: a chemical synthesis approach involving acidic pretreatment and alkaline transesterification, and a biosynthetic approach using a lipase-producing strain of the Bacillus subtilis Q5 strain. The microbial biosynthesized biodiesel was further optimized using the Plackett–Burman design. The physicochemical properties of the J. curcas methyl esters were analyzed to assess their suitability as biodiesel fuel. Initially, the raw oil had a high free fatty acid content of 13.11%, which was significantly reduced to 1.2% using sulfuric acid pretreatment, keeping the oil to methanol molar ratio to be 1:12. Afterward, alkaline transesterification of purified acid-pretreated seed oil resulted in 96% biodiesel yield at an oil to methanol molar ratio of 1:6, agitation of 600 revolutions per minute (RPM), temperature 60°C, and time 2 h. Moreover, alkaline transesterification yielded ∼98% biodiesel at the following optimized conditions: oil to methanol molar ratio 1:6, KOH 1%, time 90 min, and temperature 60°C. Similarly, the Bacillus subtilis Q5 strain yielded ∼98% biodiesel at the following optimized conditions: oil: methanol ratio of 1:9, agitation 150 RPM, inoculum size 10%, temperature 37°C, and n-hexane 10%. The fuel properties of J. curcas seed biodiesel are closely related to standard values specified by the American Society for Testing and Materials (ASTM D6751–20a), indicating its potential as a viable biodiesel fuel source

Genetic variation of wild and hatchery populations of the catla Indian major carp (Catla catla Hamilton 1822: Cypriniformes, Cyprinidae) revealed by RAPD markers

Genetic variation is a key component for improving a stock through selective breeding programs. Randomly amplified polymorphic DNA (RAPD) markers were used to assess genetic variation in three wild population of the catla carp (Catla catla Hamilton 1822) in the Halda, Jamuna and Padma rivers and one hatchery population in Bangladesh. Five decamer random primers were used to amplify RAPD markers from 30 fish from each population. Thirty of the 55 scorable bands were polymorphic, indicating some degree of genetic variation in all the populations. The proportion of polymorphic loci and gene diversity values reflected a relatively higher level of genetic variation in the Halda population. Sixteen of the 30 polymorphic loci showed a significant (p < 0.05, p < 0.01, p < 0.001) departure from homogeneity and the FST values in the different populations indicated some degree of genetic differentiation in the population pairs. Estimated genetic distances between populations were directly correlated with geographical distances. The unweighted pair group method with averages (UPGMA) dendrogram showed two clusters, the Halda population forming one cluster and the other populations the second cluster. Genetic variation of C. catla is a useful trait for developing a good management strategy for maintaining genetic quality of the species