Sustainable natural fiber reinforced composites have attracted significant interest due to the growing environmental concerns with conventional synthetic fiber as well as petroleum-based resins. One ...promising approach to reducing the large carbon footprint of petroleum-based resins is the use of bio-based thermoset resins. However, current fiber-reinforced bio-based epoxy composites exhibit relatively lower mechanical properties such as tensile, flexural strength, and modulus, which limits their wider application. Here the fabrication of high-performance composites using jute fibers is reported, modified with graphene nanoplates (GNP) and graphene oxide (GO), and reinforced with bio-based epoxy resin. It is demonstrated that physical and chemical treatments of jute fibers significantly improve their fiber volume fraction (Vf) and matrix adhesion, leading to enhanced mechanical properties of the resulting Jute/Bio-epoxy (J/BE) composites. Furthermore, the incorporation of GNP and GO further increases the tensile and flexural strength of the J/BE composites. The study reveals the potential of graphene-based jute fiber-reinforced composites with bio-based epoxy resin as a sustainable and high-performance material for a wide range of applications. This work contributes to the development of sustainable composites that have the potential to reduce the negative environmental impact of conventional materials while also offering improved mechanical properties.
The aim of this article is to report a comprehensive review of life cycle assessment (LCA) and life cycle cost (LCC) implication on residential buildings. It discusses the contemporary issues, and ...its relationship and significance of system boundary, assumptions, and reports how it effects on economic and environmental impacts. The tools, frameworks and processes of LCA and LCC of buildings are also discussed. It critically illustrates the existing LCA and LCC studies on residential house designs to determine the causes for the widely varying results of numerous previous studies. It evaluates life cycle cost and life cycle environmental impacts of a case study building, and compares with very similar LCA and LCC studies. Finally, it reports the implications and perspectives of LCA and LCC studies on building designs.
Wearable e-textiles have gained huge tractions due to their potential for non-invasive health monitoring. However, manufacturing of multifunctional wearable e-textiles remains challenging, due to ...poor performance, comfortability, scalability, and cost. Here, we report a fully printed, highly conductive, flexible, and machine-washable e-textiles platform that stores energy and monitor physiological conditions including bio-signals. The approach includes highly scalable printing of graphene-based inks on a rough and flexible textile substrate, followed by a fine encapsulation to produce highly conductive machine-washable e-textiles platform. The produced e-textiles are extremely flexible, conformal, and can detect activities of various body parts. The printed in-plane supercapacitor provides an aerial capacitance of ∼3.2 mFcm−2 (stability ∼10,000 cycles). We demonstrate such e-textiles to record brain activity (an electroencephalogram, EEG) and find comparable to conventional rigid electrodes. This could potentially lead to a multifunctional garment of graphene-based e-textiles that can act as flexible and wearable sensors powered by the energy stored in graphene-based textile supercapacitors.
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•Graphene-based screen-printed conductive, flexible, and machine-washable e-textiles•Able to capture movements demonstrating their potential as activity sensors•In-plane all-solid-state printed textiles supercapacitor showing comparable performance•Perform as EEG bio-signal electrode comparable to current rigid clinical electrodes
Health technology; Materials science; Nanomaterials
Fish assemblage and their association with major ecological factors were spatiotemporally conducted from January to December 2016 in the Atrai River, Dinajpur, Bangladesh. A total of 14,137 specimens ...belonging to 61 species, 45 genera, 18 families and 6 orders was recorded. The proportion of threatened and omnivore fish was 22.85% and 66.66%, respectively. The dominated (> 4.60%) species were Pethia ticto followed by Aspidoparia jaya, Puntius sophore, Salmophasia bacaila and Barilius barna. Temperature, depth and rainfall were the main environmental gradients to alter species biomass, biodiversity and taxonomic indices and fish assembly. The low level of river flow and water availability during autumn and winter seasons forced the fish to aggregate at higher water depth for their existence expressing unequal aquatic state and taxa. However, the study on spatiotemporal diversity of fish assemblage in this river will be an effective tool to conserve both the native and threatened species.
Dengue is a mosquito-borne viral infection that triggers a series of intracellular events in the host immune system, which may result in an invasion of the virus into the host and cause illness with ...a spectrum of severity. Depending on the degree of the infection, mild to severe clinical symptoms appear when the T-cell and B-cell-initiated immune responses fail to eradicate the virus particles and subsequently become compromised. Here, we propose a mathematically tractable simple model that exhibits important biological features of dengue infection. Dynamical analysis of our model explores the factors influencing viral persistence in the body over an extended period. To investigate plausible variability in viral dynamics in different hosts, we perform stochastic simulations of our model using Gillespie’s algorithm. Our simulation results recapitulate the distribution of the intrinsic incubation period, daily viral load, and the day of peak viremia. In addition, we observe that the invasion probability of the virus into the host is correlated with the initial virus population injected by the mosquito. However, considering the biting behavior of Aedes mosquitoes, a lower initial virus injection could end up increasing the epidemic potential of the virus.
Three similar‐structure InGaN/AlGaN multiple‐quantum‐well near‐ultraviolet (NUV) light‐emitting diodes (LEDs) are utilized to investigate the microscopic effect of defects on strain relaxation. ...Consistent correlations among the crystal quality, the piezoelectric field (FPZ), the internal quantum efficiency (IQE), and the bandgap shrinkage of NUV LEDs are obtained by investigating the macroscopic characterizations. The difference in crystal quality (or the defect density) of NUV LEDs is found by the ideality factor, the emission microscope image, the Shockley–Read–Hall coefficient, and the IQE. Electroreflectance spectra are used to calculate FPZ of NUV LEDs. FPZ, the IQE, and the peak‐wavelength shift at driving currents are increased with the samples’ crystal quality compared to the reference sample. Also, FPZ, the IQE, and the peak‐wavelength shift are decreased with the increase in samples’ defect densities. A similar result is found for the bandgap shrinkage. This effect significantly indicates that the strain relaxation is induced by defects. Herein, a model that systematically explains the observed changes in macroscopic properties of NUV LEDs is proposed.
The effect of point defects on piezoelectric field is investigated by similar‐structure near‐ultraviolet light‐emitting diodes. It is found that the piezoelectric field, the radiative recombination rate, and the redshift in peak wavelength increase with the samples’ crystal quality compared with the reference sample. These optoelectronic characterizations reveal that the samples’ strain relaxation is caused by defects.
•The impact of asymptomatic individuals on the transmission dynamics is taken into account.•Local and global stability is confirmed through rigorous mathematical analysis.•Outcome is analyzed over ...different regimes of important parameters.•To reduce the social and economical burden of epidemic, an optimal control model is introduced.
Asymptomatic carriers serve as a potential source of transmission of epidemic diseases. Exposed people who develop symptoms only get tested and remain isolated in their homes or sometimes in hospitals when needed. In contrast, the asymptomatic individuals go untested and spread the disease silently as they roam freely throughout their entire infectious lifetime. The work intends to explore the role of asymptomatic carriers in the transmission of epidemic diseases and investigate suitable optimal control strategies. We propose a SEIAQR compartmental model subdividing the total population into six different compartments. To illustrate the model’s implication, we estimate the number of asymptomatic individuals using COVID-19 data during June 9–July 18, 2021 from Bangladesh. We then analyze the model to explore whether the epidemic subsides if the asymptomatic individuals are tested randomly and isolated. Finally, to gain a better understanding of the potential of this unidentified transmission route, we propose an optimal control model considering two different control strategies: personal protective measures and isolation of asymptomatic carriers through random testing. Our results show that simultaneous implementation of both control strategies can reduce the epidemic early. Most importantly, sustained effort in identifying and isolation of asymptotic individuals allows relaxation in personal protective measures.
In this talk we have applied an enhanced (G′/G)-expansion method to find the traveling wave solutions of the (2+1)-dimensional Zoomeron equation. The efficiency of this method for finding the exact ...solutions has been demonstrated. As a result, a set of exact solutions are derived, which can be expressed by the hyperbolic and trigonometric functions involving several parameters. When these parameters are taken as special values, the solitary wave solutions and the periodic wave solutions have been originated from the exact solutions. It has been shown that this method is effective and can be used for many other nonlinear evolution equations (NLEEs) in mathematical physics.
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.
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•Bangladesh inches towards intensive farm mechanization.•Locally manufactured farm machineries lack precision technology.•Custom-hiring of machineries works as a ownership model for the poor farmers.•Mechanizing transplantation of paddy requires immediate attention, and.•Engaging rural youth is crucial for the sustainability of farm mechanization.
We investigate the cause of the optoelectronic performance variations in InGaN/GaN multiple-quantum-well blue light-emitting diodes, using three different samples from an identical wafer grown on a
...-plane sapphire substrate. Various macroscopic measurements have been conducted, revealing that with increasing strain in the quantum wells (QWs), the crystal quality improves with an increasing peak internal quantum efficiency while the droop becomes more severe. We propose to explain these variations using a model where the in-plane local potential fluctuation in QWs is considered. Our work is contrasted with prior works in that macroscopic measurements are utilized to find clues on the microscopic changes and their impacts on the device performances, which has been rarely attempted.
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