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Building materials, such as brick and concrete, are known indoor radon (222Rn) and thoron (220Rn) sources. Most radon and thoron exhalation studies are based on the laboratory testing of pieces and blocks of such materials. To discuss if laboratory findings can be applied to a real-world environment, we conducted intensive in situ exhalation tests on two solid concrete interior walls of an apartment in Japan for over a year. Exhalation rates of radon (JRn) and thoron (JTn) were measured using an accumulation chamber and dedicated monitors, alongside monitoring indoor air temperature (T) and absolute humidity (AHin). There were weak correlations between JRn or JTn and T or AHin at one tested wall, and moderate correlations of JRn and strong correlations of JTn with T or AHin at the other wall, meaning more or less seasonal variations. The findings aligned with previous laboratory experiments on JRn but lacked corresponding data for JTn. Additionally, a moderate or strong correlation between JRn and JTn was observed for both tested walls. Comparison with theoretical calculations revealed a new issue regarding the impact of each process of emanation and migration within concrete pores on radon and thoron exhalation. Overall, this study provides insight into parameterizing radon and thoron source inputs in modeling the spatiotemporal dynamics of indoor radon and thoron. [ABSTRACT FROM AUTHOR]

This paper reports an empirical study on the practice and effectiveness of online EFL teaching during COVID-19. Teachers had to shift to an online mode of teaching very suddenly with no previous experience and without much preparation. Their practices and effectiveness were investigated using the Technological Pedagogical and Content Knowledge (TPACK) theoretical model as the framework. A mixed method research design was planned and carried out in Bangladeshi universities using a web-based survey and indepth interviews. Data from 50 university English teachers highlight the need for a student-oriented perspective in teacher education and the creation of online teaching-based teacher development programmes (TDP) to enhance students' experiential learning in online platforms, in line with the 'learning technology by design' approach. More importantly, the element of "Context" (XK) and "Classroom Management Knowledge" (CMK) have emerged as important 'new' tenets of TPACK. Hence, a revised version of TPACK is suggested. Further research and discussions are advocated before it could be established and propagated as an acceptable version of TPACK. [ABSTRACT FROM AUTHOR]

Radon, an element of natural radiation, is considered one of the leading causes of lung cancer worldwide. In Bangladesh, radon has been clarified as a foremost source of radiation exposure. Potential natural-radiation-induced elevated cancer risks were estimated in Bangladesh previously for the population. In this survey, as a very preliminary study in the country, comparative indoor radon (222Rn, Rn) and thoron (220Rn, Tn) concentration/population exposure was determined for the multistoried dwellings of south-western areas of Dhaka city. RADUET was used to assess annual Rn and Tn concentrations in determining the primary inhalation dose for the population. The annual effective dose of Rn and Tn was evaluated in this study for dwellings at 0.3 mSvy−1, constituting a Tn dose contribution of an average of 40% with a dwelling-based wide range of 10–96%. Thus, Tn should not be neglected for Bangladesh while estimating radiological inhalation dose from the indoor environment. Again, the equilibrium factors, F of Rn and Tn, were determined by short-term measurement at averages of 0.6 and 0.02, respectively. Furthermore, using questionnaire estimation by principal component analysis, PCA following the dwelling characteristics, human lifestyles, and estimated long-term indoor Rn and Tn concentrations, this paper discussed indoor atmospheric/Rn factors for the investigated multistoried dwellings in Dhaka city. [ABSTRACT FROM AUTHOR]

Indoor radon is a major hazard to human health; it is one of the leading causes of lung cancer. Therefore, radon research in Asia has intensified recently due to the growing awareness of the harm that radon poses. An analysis of the collected literature data showed that in Asia–Oceania, some regions have—or are believed to have—little indoor radon problems due to climate and low Rn ground. It can be concluded that countries have their own approaches, techniques, and protocols. Data were not harmonized within each region; however, measurement techniques were compared by regional intercomparison exercises. The situation differs regarding studies on the usability of radon as a tracer or potential predictor of tectonic phenomena, as some countries are in seismically active zones, such as India, Taiwan, China, Japan, etc. India and Taiwan are global leaders in this research, as well as Italy, which is another seismically affected country. We provide an overview of radon-related surveying and research activities conducted in the western, southern, and eastern Asian regions over the past few years. Additionally, we observed that the number of indoor radon measurements per million inhabitants increases as the human development index (HDI) increases. [ABSTRACT FROM AUTHOR]

To investigate the effect of cow dung and chemical fertilizers on the growth and yield performances of mungbean (BARI Mung 6), an experiment was carried out in the research field of the Sher-e-Bangla Agricultural University, Dhaka, during the kharif season of 2020. The experiment was laid out as a randomized complete block design (RCBD) with three replications comprising seven manure-fertilizer treatments. The results showed that the different levels of cow dung and fertilizers significantly influenced mungbean growth parameters and seed yield. The highest plant height (48.2 cm), number of leaves plant-1 (10.3), number of branches plant-1 (3.9), maximum number of pods plant-1 (19.3), seeds pod-1 (10.4), 1000-seed weight (43.4g), and the highest seed yield (1.42 t ha-1) were obtained from the application of 80% of the recommended dose of fertilizers (RDF) plus 20% cow dung. It is concluded that applying 20% cow dung (1.2 t ha-1) coupled with 80% of the recommended amount of fertilizers together produced superior results for the growth and yield of mungbean compared to applying fertilizer or cow dung alone. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive performance assessment of a two-stage power electronic (PE) converter for interfacing the grid of a lithium-ion battery energy storage system (Li-BESS) for building-integrated PV (BIPV) applications. A performance assessment of the control system was conducted for the two-stage PE interface with a common DC-link, which consisted of a bi-directional boost converter with a cascaded PI controller and an AC/DC converter with proportional-integral (PI) and proportional-resonant (PR) controllers. The assessment covered loss analysis and useful lifetime estimation for the 10 kW PE interface with a wide-bandgap SiC power MOSFET at different loads for both the charging and discharging modes of a 50 kWh lithium-ion battery system. Additionally, a performance comparison of various switching frequencies was performed. It was observed that the system was stable up to a switching frequency of 30 kHz, and that increasing the switching frequency improved the responsiveness of the converter by decreasing the settling time; however, there were diminishing returns at higher switching frequencies. To obtain a proper balance between responsiveness and lower loss, a switching frequency of 10 kHz was selected. [ABSTRACT FROM AUTHOR]

The global promotion of electric vehicles (EVs) through various incentives has led to a significant increase in their sales. However, the prolonged charging duration remains a significant hindrance to the widespread adoption of these vehicles and the broader electrification of transportation. While DC-fast chargers have the potential to significantly reduce charging time, they also result in high power demands on the grid, which can lead to power quality issues and congestion. One solution to this problem is the integration of a battery energy storage system (BESS) to decrease peak power demand on the grid. This paper presents a review of the state-of-the-art use of DC-fast chargers coupled with a BESS. The focus of the paper is on industrial charger architectures and topologies. Additionally, this paper presents various reliability-oriented design methods, prognostic health monitoring techniques, and low-level/system-level control methods. Special emphasis is placed on strategies that can increase the lifetime of these systems. Finally, the paper concludes by discussing various cooling methods for power electronics and stationary/EV batteries. [ABSTRACT FROM AUTHOR]

Selection criteria is very crucial to pick up promising genotypes in a breeding program. An experiment was conducted with twenty soybean genotypes following a randomized complete block design to study the inheritable agronomic traits, their interrelation and partitioning of genotypic correlation into direct and indirect effects to identify the traits responsible for higher seed yield. Results indicated that phenotypic variance was higher than that of genotypic variance for all the characters. The highest PCV was found for the trait seed yield per plant (39.03%) followed by yield per plot (32.85%). The higher GCV was also found for the same traits-seed yield per plant (37.36%), yield per plot (27.23%). PCV and GCV was the lowest for trait days to maturity (6.28%, 4.16%) and days to flowering (3.20%, 2.24%). Estimated broad sense heritability was ranged from days to flowering (44.05%) to seed yield per plant (91.62%). Higher estimate of heritability was also observed for yield per plot (88.65%) followed by hundred seed weight (85.39%) whereas; heritability was moderate for plant height (76.75%) and pod per plant (70.17%). The genetic advance was the highest for plant height (19.39%). On the other hand, primary branch per plant, days to flowering and days to maturity showed low heritability with low GA depicts the influence of non-additive gene effect. Pod per plant, hundred seed weight, days to maturity and plant height is positively and significantly correlated with yield. Pod per plant (0.908) and hundred seed weight (0.907) showed highest direct positive effect on seed yield at genotypic level. Path analysis also confirmed highest positive direct effect of hundred seed weight (0.701). So, the present study suggests that, higher hundred seed weight and pod per plant can be effective selection measure for improvement of soybean yield. [ABSTRACT FROM AUTHOR]

This paper develops a multi-objective co-design optimization framework for the optimal sizing and selection of battery and power electronics in hybrid battery energy storage systems (HBESSs) connected to the grid. The co-design optimization approach is crucial for such a complex system with coupled subcomponents. To this end, a nondominated sorting genetic algorithm (NSGA-II) is used for optimal sizing and selection of technologies in the design of the HBESS, considering design parameters such as cost, efficiency, and lifetime. The interoperable framework is applied considering three first-life battery cells and one second-life battery cell for forming two independent battery packs as a hybrid battery unit and considers two power conversion architectures for interfacing the hybrid battery unit to the grid with different power stages and levels of modularity. Finally, the globally best HBESS system obtained as the output of the framework is made up of LTO first-life and LFP second-life cells and enables a total cost of ownership (TCO) reduction of 29.6% compared to the baseline. [ABSTRACT FROM AUTHOR]

Mechanical energy stored in an oscillating cantilever in frequency modulation atomic force microscopy (FM-AFM) was dissipated through nonconservative interactions between a sample and a tip on the cantilever. The energy dissipation (D dis) was measured using FM-AFM with a metal-coated tip for a metal-coated Si substrate partly covered with thin mica films. At tipâ€"sample separations where electrostatic force was dominant under a bias voltage, Joule heat was generated owing to the tip oscillation, responsible for D dis. From analysis of D dis and the frequency shift of the cantilever, electric resistance responsible for the Joule heat was estimated to be of the order of GΩ. The great values of the resistance were discussed in the terms of surface scattering of charges moved by the oscillating tip and the dielectric energy loss in the mica films. Measurement of the energy dissipation exhibited potential to probe the local surface electronic properties in non-contact. [ABSTRACT FROM AUTHOR]

A newly developed pentagonal photonic crystal fiber (P-PCF) with high nonlinearity and birefringence has been introduced in this work. Numerical analysis is carried out across the broader wavelength spectrum from 1.0 to 2.0 μm within the inferred region (IR). Furthermore, using the finite element method (FEM) with smaller mesh, a numerical examination of several optical characteristics such as effective mode area (EMA), nonlinearity, numerical aperture (NA), birefringence, and V-parameter was carried out. By using a circular completely matched layer (PML), the proposed P-PCF's optical transmission qualities have been guided. For the x-polarization mode, the suggested P-PCF exhibits high nonlinearity of 1.6 × 104 W−1 Km−1 at the working wavelength of λ = 1.4 µm. Furthermore, the proposed structure offers strengthening birefringence 2.5 × 10–6 at 1.6 μm wavelength including numerical aperture (NA) of 0.44 for the X-polarization mode. Based on the outstanding advantages, it can be asserted that the suggested model will find a promising domain of application in the area of all optical signal processing, sensing applications, and coherent optical communications. [ABSTRACT FROM AUTHOR]

Potentially higher cancer risk due to exposure from natural background radiation was indicated for the Bangladeshi population by estimations based on the countrywide study. Several regions with elevated natural background exhibited higher soil radium and thorium contents than the world average. Being the decay products of these radioactive elements, natural radon isotopes could constitute environmental risk factors for internal radiation exposure to the lungs of people living in these areas. Although lung cancer is one of the most prevalent types of cancer in Bangladesh, its status and features are still unclear. To clarify the present status of one of the potential risk factors for lung cancer in the country, this review intends to ascertain the countrywide radon exposure, and its pathways by types of local dwelling and by regions, which would provide an indication of the internal exposures in areas of elevated natural background radiation and radionuclides of soil as well as an understanding of the preliminary contribution of environmental radon on the country's lung cancer prevalence. In this review, countrywide monitored air radon exposures for Bangladeshi dwellings and workplaces are organized from peer-reviewed published papers. Radon has been identified as one of influential sources of radiation dose in Bangladesh with its higher radon exhalation and emanation rate from soil. A novel nationwide depiction of the overall assessed indoor and soil radon levels for Bangladesh has been made through radiation maps. This would be helpful for designing future systematic radon/radiological monitoring and research on the country's lung cancer prevalence. [ABSTRACT FROM AUTHOR]

In this work, an excellent design of photonic crystal fiber (PCF) with five layers of a hexagonal lattice of air holes (AHs) of cladding region as well as two elliptical air holes in the core area (CA) has been presented for terahertz (THz) wave pulse propagation. The finite element method with perfectly matched layers has been used to design our proposed fiber L-PCF to achieve the low effective material loss (L-EML) in the terahertz regime for communication applications. After the simulation procedure, our proposed low-loss PCF (L-PCF) fiber shows a low effective material loss of 0.007 cm−1, with power fraction (PF) in the core area of 80% and a large effective area of 3.46 × 10–8 m2 at 1 terahertz (THz). Moreover, other optical properties such as V-parameter, scattering loss, and confinement loss are also reported here. For different types of optical and telecommunication applications, our suggested L-PCF fiber will be highly suitable at the terahertz (THz) waveguiding. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) demand in Bangladesh has increased significantly in recent years, becoming the second major staple cereal after rice (Oryza sativa L.). Domestic production of wheat accounts for only 16% of domestic use. More than 30 wheat varieties have been released in the past 30 yr by the Bangladesh Wheat and Maize Research Institute (BWMRI). In the last 10 yr alone, nine varieties with improved yield and disease resistance have been released. Bangladesh and the BWMRI lack the regulatory framework and infrastructure to accurately track the rate of adoption of these new releases. To determine the adoption of these varieties across the country, DNA fingerprinting of wheat samples was conducted across the six wheat growing regions in Bangladesh during the 2018–2019 cropping season. A reference library was established to compare and identify the wheat samples collected from farmers' fields. Wheat grain samples collected from the fields and breeders' lines were genotyped using Diversity Arrays Technology sequencing (DArTseq)‐based single nucleotide polymorphism (SNP) markers. Of the 1,791 samples collected from farmers' fields, 68% were identified as varieties released after 2000 and 32% matched with older varieties. Among the varieties grown, BARI Gom 25 represented 29% of the collected samples followed by 23% of BARI Gom 24 and 16% of BARI Gom 26. These three most common varieties were well distributed across the six regions and have broad adoption. Core Ideas: High throughput DNA fingerprinting can be efficiently used for assessment of varietal adoption.68% of samples identified as varieties released after 2000 and 32% matched with older varieties.Improving management of wheat breeder seed is essential for accurate adoption studies. [ABSTRACT FROM AUTHOR]

In this study, photonic crystal fiber in quasi pattern (Q-PCF) has been proposed at the terahertz (THz) regime. In Q-PCF, the core area is designed using the two elliptical air holes for the best performance of optical communications to obtain the ultra-low effective material loss (EML). In Q-PCF, perfectly matched layer (PML) and the finite element method (FEM) have been applied to simulate the desired outcomes. The mentioned Q-PCF is optimized by shifting the core diameter, cladding air holes pitch and diameter, porosity of the model, and background materials. The numerically controlled outcomes ensure an EML of 0.01542 cm−1 with high power fraction response at 1 THz frequency. In addition, other loss profiles and operating modes have also been well described. Moreover, operating mode profile indicates single mode propagation up to 2.2 THz operating frequency. The noted outcomes ensure that the designed structure will be perfectly suitable for long distance broadband optical communication applications in THz technology. [ABSTRACT FROM AUTHOR]

Cloud chamber contributes to radiation education by facilitating observation of particle tracks formed by radiation. Peltier-based chamber achieves cooling without the need for dry ice,. we developed a cloud chamber based on peltier thermoelectric modules and has a multilayered heat insulation system to maintain a stable cool environment. It produces sharp particle tracks without requiring a dark room for observing the tracks. Its large top window (diameter of 12.5 cm) provides a relatively wider observation field capable of accommodating five to six students at a time. [ABSTRACT FROM AUTHOR]

This study was accomplished to find out the qualities of tannery effluents with the assessment of Physicochemical parameters of effluents liberated by the tanneries in Dhaka, Bangladesh. Effluents were gathered from nine tanneries and three ejected points of area Hazaribagh, Dhaka. Various physical and chemical properties like Alkalinity, Biological Oxygen Demand , Chemical Oxygen Demand , Chloride, Color , Dissolved Oxygen , Electrical Conductivity , Nitrate, Odor, Phosphorous, , Sulphate, , Suspended Solid, Temperature, The pH, total Dissolved Solids etc. were evaluated and matched up to standard levels .The observed ranges of the values are 1072-3833 mg/L for TSS, 1251-6240 mg/L for COD, 3.2-10.43 for pH, 2375-4385 mg/L for TDS, 200-1257 mg/L for BOD5, 7.81-13.85 mg/L for phosphorous, 2100-9745.8 μs/cm for EC, 684-1020.2 mg/L for alkalinity, 2.85-22.34 mg/L Cr3+, 8-26 mg/L for NO3 - ,484-1928 mg/L for Cl-, 0.68-2.8 mg/L for NO2 - and 124-512 mg/L for SO42-. [ABSTRACT FROM AUTHOR]

Activities in the Bangladeshi leather industries have the potential to cause chemical pollutions thereby deteriorating the working environments, the surrounding residential areas, or even foodstuffs. Therefore, it is important to determine the chemical exposures among the industry workers and residents of the surrounding areas who may be directly or indirectly impacted by the contaminated environment. This study focused on evaluating the hazard arising from exposure to metals due to industrial contamination. Tissue samples of hair and nails were collected from both the leather industry workers and residents in the vicinity of the industries. Using chromium as an indicator of contamination/exposure from the leather industry, it was the most significant metal contaminant for industry workers ranging from 21.85 to 483 mg/kg and for industry-neighboring residents at 6.01 to 296.16 mg/kg. Both the workers and neighboring residents were found to be excessively exposed (P < 0.05) to chromium compared with the investigated control group of people living in a distant village area which had no industrial establishments. [ABSTRACT FROM AUTHOR]