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This paper proposed a compact, high-sensitive S-band microwave sensor for low permittivity characterization. The proposed microwave sensor is inspired by a metamaterials-based maze-shaped split-ring resonator (MS-SRR) configuration, and its overall dimensions are 25 mm × 20 mm × 0.79 mm. The unloaded state of the proposed sensor achieved two robust band-stop notches in its transmission response at 2.77 GHz and 3.08 GHz, respectively. These distinctive features enable the real-time measurement of permittivity in low-permittivity materials. The MS-SRR configuration accomplished strong electric-field intensity, which increased the interaction between the field and testing material, resulting in a highly sensitive measurement. A sensitivity of 11.91% is observed for the first resonance peak and 12.01% for the second peak within the permittivity range from 1 to 2.0. Moreover, the proposed sensor is also competent in measuring the permittivity range between 3 and 10 with a sensitivity of 9.47%–4.93% for the first peak and 9.57%–4.83% for the second peak. The resonance frequency shifting by the influence of material under test (MUT) is presented as a function of permittivity using a regression model. The simulated, measured and formulated results agree well. Finally, the proposed compact and high-sensitive microwave sensor holds promise for low permittivity characterization applications.

This article proposed a labyrinth shape circular split ring resonator (LC-SRR) based microwave sensor for material permittivity characterization at L to S-band applications. The proposed sensor achieved miniaturized dimensions of only 25 × 20 mm2 by utilizing fractal technology. This new design strategy adopts a unique and compact structure and high electromagnetic (EM) field intensity, contributing to a more precise sensing mechanism in the microwave frequency range. The design geometry achieved resonant frequency at 2.57 GHz with a notch depth of −29.5 dB. The design evolution, metamaterial characteristics, equivalent circuit model, and electric (E) and magnetic (H) fields are presented to understand the stopband characteristics at the resonant frequency. A high sensitivity of 10.50 % is achieved for the proposed sensor for the permittivity range from 1 to 2. The reflection and transmission characteristics of the proposed LC-SRR based sensor are validated by fabricating and measuring the prototype. Moreover, the sensor performance is validated using different dielectric materials (Roger RT5880, Roger RO4350B, and FR-4) The measurement results show consistency with simulation results. Finally, the miniaturized low-profile sensor structure and high sensitivity to characterize the permittivity of the material makes the proposed sensor suitable for low-permittivity sensing applications.

Background: Canavalia rosea is a common tropical seacoast flowering plant from the family of Fabaceae which is reported as bay bean and coastal jack bean; has a wide range of therapeutic and nutraceutical properties. Aim: The present research aims to explore some pharmacological insights of the methanol extract C. rosea of leaves (MECR) and its chloroform fraction (CFCR) and n-hexane fraction (NFCR) through in-vitro and in-silico approaches. Methods: Different fractions of C. rosea were subjected to ferric reduction assay and total phenolic and flavonoid content assay to explore their antioxidant potential. The anti-inflammatory activity was assessed on the hypotonic-induced human erythrocyte-lysis model, while the protein denaturation method was applied for screening anti-arthritis properties of plant extract; and the cytotoxic activity was evaluated by brine shrimp lethality bioassay. In the in-silico study, molecular docking, pass prediction and ADME/T, analysis was used to investigate anti-arthritic, anti-inflammatory, antioxidant and cytotoxic potency of five selected compounds of C. rosea. Finally, the quantum chemical density functional test analysis was applied to investigate the chemical and physical properties of those compounds. Results: All the soluble organic extracts of C. rosea demonstrated moderate toxicity with strong antioxidants potential, in which MECR manifested the peak level of scavenging activity (2.49) on ferric reduction assay. MECR, CFCR & NFCR significantly protected lysis of human erythrocyte membrane induced by hypotonic solution, whereas MECR and CFCR were exhibited partially equal inhibitory activity. The in-vitro anti-arthritis assay, MECR, NFCR and CFCR showed strongly significant (p˂0.001) inhibitory potency at 500 μg/mL & 1000 μg/mL concentrations. The molecular docking simulations revealed strong binding of all compounds to specific receptors, with Rutin showing the highest biological reactivity followed by Daucosterol, β-Sitosterol, Stigmasterol, and Guanidine. All the compounds showed favorable reactivity patterns, with O and H atoms poised for nucleophilic and electrophilic attacks in chemical density functional calculations. Conclusion: The recent investigation suggests that C. rosea could have the potential source of antioxidant, anti-inflammatory, anti-arthritis and cytotoxic activity, prompting further investigation into their mechanisms.

In Bangladesh, where agriculture forms the backbone of the economy, efficient grain storage is crucial, particularly for paddy storage. Traditional methods like gunny bags and plastic containers are common, but the recent introduction of hermetic storage technologies, such as GrainPro bags and hermetic cocoons, have significantly reduced postharvest losses paddy. However, most research focuses on oxygen (O2) and carbon dioxide (CO2) levels in those open storage systems. This study introduces an innovative, cost-effective remote monitoring system for hermetically sealed grain storage, designed using locally sourced components, including a Digital Hygrometer, WiFi Mini IP Camera, and a Remote Controller unit. Tested over a 125-day period at Advanced Storage Lab, Bangladesh Agricultural University, the system effectively monitored the internal environment of the storage units. Key findings show that the internal temperature of the storage bags varied between 16.7°C and 29.2°C, demonstrating lesser fluctuation compared to the ambient temperature range of 16.1°C to 33.5°C. The relative humidity inside the storage units remained stable between 45 % and 54 %, in contrast to the external humidity range of 45 % to 81.2 %. Additionally, using the Steffe and Singh equation, an increase of 0.512 % in Equilibrium Moisture Content (EMC) of paddy was recorded. Notably, there was no evidence of insect or mold growth after 125 days of storage. This study's remote monitoring system not only marks a significant advancement in hermetic grain storage technology but also contributes to sustainable agricultural practices. It provides a practical, real-time solution to monitor and manage key environmental parameters, ensuring the preservation of grain quality over time.

In response to environmental concerns, researchers explore fly ash as a cement replacement material, and crushed bricks as a cost-effective and load-reducing aggregate, particularly where stone chips are scarce. Therefore, this study investigates the mechanical properties and microstructure of brick aggregate concrete (BAC) with raw fly ash (FA) as a partial replacement of cement. The research involved casting raw FA based BAC (FBAC) cylinders (100 mm diameter and 200 mm height) and prism (100 × 100 × 500 mm) with varying levels of FA (0–25%) using a constant mix proportion by volume of 1:1.5:3 (cement : fine aggregate : coarse aggregate) with a water to binder (w/b) ratio of 0.50 and three curing ages (7, 28, and 90 days). Tests for mechanical properties, including compressive strength, split tensile strength, flexural strength, modulus of elasticity, and Poisson's ratio were conducted to assess the behavior of FBAC, and microstructure were then investigated at 28 days. The results indicated that increasing the FA content up to 15% led to gradual improvement in compressive strength and tensile strength values. At 28 days, the highest values of compressive strength and split tensile strength were observed at 10% FA, with 7.9% and 14.2% increase, respectively, compared to the control concrete. However, the flexural strength of FBAC decreased gradually with cement replacement. On the other hand, modulus of elasticity and Poisson's ratio increased gradually up to 20% and 25% cement replacement, respectively. Up to 15% FA enhanced a more uniform and compact microstructure than that of control concrete. Several equations have been developed to express relationship between compressive strength and other mechanical properties of FBAC. Hence, up to 15% raw FA as a partial replacement of cement improved the mechanical properties and microstructure of BAC.

Forest conservation and livelihood improvement are the prime goals of forest-protected area co-management widely practiced in tropical countries. In Bangladesh, the co-management of protected areas (PA) started in 2004 with the funding of donor agencies involving the forest department (FD), non-government organizations (NGOs), along with the communities living in and around the forests. Thus, it is imperative to decipher the impact of co-management on the livelihood of forest-dependent communities (FDC) and forest cover change. The data on livelihood improvement were collected through quantitative and qualitative methods, while satellite data (Landsat images of the years 2008, 2015, and 2022) were utilized to detect forest cover change. The finding indicates that the co-management approach has positively impacted the livelihood of FDC by securing their income sources. The alternate income-generating activities (IGAs) provided to the FDC aids in securing income and livelihoods. However, the communities have experienced antagonistic relationships with forest officials, undesirably influencing their livelihoods. Reducing the dissent on forest management activities between forest officials and participants of the co-management program might positively impact the restoration of the PA. The forest cover area has increased by 18 ha just after the finish of the co-management program, and 18.9 ha has risen from 2009 to 2022. This forest cover increase might be due to the plantation in the denuded areas and livelihood improvement through IGAs posing less pressure on the forest. Therefore, co-management of the Sal forest might increase forest cover and improve the livelihood of FDC.

Mechanized farming is an indispensable part of modern agriculture. Bangladesh has managed to achieve significant progress in some components of farm mechanization i.e., irrigation and tillage. The majority of the agricultural operations are still being carried out with manual labor. This paper reports the status of agricultural machineries in the country while analyzing the historical policy changes towards intensive farm mechanization. The potential sectors requiring urgent attention for mechanization was also identified in this study. The manuscript discusses how mechanization could help ensure the food security of the country by maintaining timeliness of agricultural operation. Urgent introduction of mini-combined harvesters during COVID-19 pandemic was discussed as a commendable decision taken by the Government of Bangladesh. It also shows how the use of machine power is increasing in the country through custom hiring based ownership models of the machineries. Local manufacturing of agricultural machineries and spare parts was championed by the fact that small scale industries have developed in this sector. In line with this, we argued that the local companies should focus on precision manufacturing in the coming days. The manuscript also urged the need to include rural youth for sustainable farm mechanization process.