ABSTRACT
Bangladesh imports roughly 98% of cotton from abroad to produce fabric or yarn (USDA 2020. Cotton and Products Update. Bangladesh. Also available at https://apps.fas.usda.gov/newgainapi/api/Report/DownloadReportByFileName?fileName=Cotton%20and%20Products%20Update_Dhaka_Bangladesh_11-30-2020). The production of textiles in Bangladesh depends on the price of raw material, the demand for garment products in the importing countries, smooth supply chain management, and the domestic supply of cheap garment laborers. The global pandemic of COVID-19 disrupted the supply chain of almost all physical goods and services, including textiles. It caused the price of textiles to fall due to a drop in worldwide demand, and increased the marginal cost of textile production due to supply chain interruptions. This paper shows how the decline in the demand for garments, coupled with an increase in cost, shrinks the producer welfare of textile manufacturing and garment exports of the small producing country, Bangladesh.
ABSTRACT
The chloroxylenol (PCMX) has shown well virucidal efficacy against COVID-19, but the large-scale utilization of which will undoubtedly pose extra environmental threaten. In the present study, the recycled industrial phenylenediamine residue was used and an integrated strategy of "carbonization-casting-activation" using super low-dose of activator and templates was established to achieve in-situ N/O co-doping and facile synthesis of a kind of hierarchical hyperporous carbons (HHPC). The sample of HHPC-1.25-0.5 obtained with activator and template to residue of 1.25 and 0.5 respectively shows super-high specific surface area of 3602 m2/g and volume of 2.81 cm3/g and demonstrates remarkable adsorption capacity of 1475 mg/g for PCMX in batch and of 1148 mg/g in dynamic column adsorption test. In addition, the HHPC-1.25-0.5 exhibits excellent reusability and tolerance for PCMX adsorption under various ionic backgrounds and real water matrix conditions. The combined physio-chemistry characterization, kinetic study and DFT calculation reveal that the enhanced high performances originate from the hierarchical pore structure and strong electrostatic interaction between PCMX and surface rich pyridinic-N and carbonyl groups.
ABSTRACT
Natural aggregates are being depleted due to the high demand for road and building construction and need to be replaced with alternative materials. This study investigated the potential of using Palm kernel shells (PaKS) as a partial replacement for natural aggregates (NA) and waste plastics (WP) as a binder. The physical and volumetric properties of the different asphaltic mixes (AM) were assessed using the Marshall Method. The bitumen content of the mix design samples was varied from 4.0% to 7.5% of the total weight of aggregates utilized. According to the Marshall parameters, at 5.5% bitumen content, the maximum Marshall Stability value of the different mix designs increased from 9.8 kN to 12.1 kN and the flow value increased from 3.0 mm to 3.7 mm. The experimental results based on the optimum bitumen content determined by the Marshall method demonstrate that PaKS and WP can be utilized to modify AM. However, additional tests will be needed to evaluate the use of this composition in road construction.
ABSTRACT
The COVID-19 pandemic also raised questions about the practice of physical activity using a face mask and how this would affect breathing and performance. The aim of this study was to investigate the effects of using a tissue face mask recommended by the World Health Organization (WHO) on the variation of heart rate (HR), minute volume (VE), and muscle O 2 saturation (SO 2 m) parameters during performing the incremental load exercise and verifying the maximum time obtained at the end of the exercise. A 21-year-old male, 85 kg of total body mass and 1.68 m of height were selected. The individual performed an incremental load test to maximum exhaustion on the XT cycle ergometer (TRG Fitness ..) in two moments: No mask -Control (C);Cloth Mask (CM). The individual was instructed to maintain a cadence of 61-65 rpm and every 2 minutes a load of 30.8 watts was added until maximum exhaustion. A ventilometer VO2 Pro (Cefise ..) and a near infrared spectroscopy sensor (Moxy ..) were used, placed in the vastus lateralis muscle of the right leg. Data were analyzed every 20% of the total time (20%, 40%, 60%, 80% and 100%) under conditions C and CM. The parameters of HR, VE and SO 2 m were monitored throughout the test and the data were statistically processed by a software (Origin Pro .. 3.226) using a multivariate analysis technique (Principal Component Analysis -PCA) to analyze interrelationships between the variables. In test condition C, an eigenvalue of 2.979 was observed with two variables (VE and SO 2 m) associated with greater variation (PC1). The maximum time obtained at the end of the test was 1535 seconds. In the CM condition, na eigenvalue of 2.881 was observed with two variables (HR and SO 2 m) associated with greater variation (PC1). The maximum time obtained at the end of the test was1330 seconds. It is concluded that the use of CM reduces VE variation, which may be associated with greater airflow resistance. The greatest variation observed in HR was due to the use of CM, impacting the delay in the appearance of the plateau. In addition, the use of a tissue mask recommended by the WHO reduces the maximum exercise time performed on the cycle ergometer in a healthy individual. These findings are useful for evaluating the effects of using CM in high-performance sports. Additional studies in the elderly and people with lung or heart disease are needed.