Advances in Cellulose Nanomaterial-based Foams for Environmental Applications

The use of metal-oxide nanoparticles adsorbents is limited to fixed-bed columns in industrial-scale water treatment applications. This limitation is commonly attributed to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials, or a lack of adsorption capacity. Foams and aerogels derived from cellulose nanomaterials have unique characteristics, such as high porosity and low density, which enables their use in a variety of environmental applications, including water treatment. However, the overall use of cellulose nanomaterial-based foams in various environmental sectors is limited due to the high cost of production associated with time- and cost-intensive manufacturing processes such as freeze-drying and supercritical CO2 drying. In addition, additive manufacturing is a prominent technology for accurately developing and controlling micro-to-macrostructures with continuous automation; however, the use of cellulose-based materials in additive manufacturing is also limited due to its complex processing route involved in different stages of manufacturing. Hence this dissertation initially assessed the feasibility of the synthesis and immobilization of magnesium-doped amorphous iron oxide nanoparticles (IONPs) on the surface of a freeze-dried and crosslinked cellulose nanofibril (CNF) aerogel for arsenic removal from water. The adsorption kinetics and isotherms were studied for both As(III) and As(V). Further work involved the use of urea as an additive to develop a microwave-assisted thawing procedure for creating CNF-based hybrid foams at a significantly shorter time and lower energy consumption than any previously reported methods. A freezing rate-dependent mechanism for foam formation was proposed, along with a new crosslinking pathway that was confirmed by FTIR and nitrogen content analyses. The foams\u27 mechanical properties were examined in both dry and wet conditions. In addition, the dissertation provides with an investigation for the 3D-printability of a CNF paste by optimizing the solid content of CNFs with the composition of urea and carboxymethyl cellulose (CMC). The amplitude-sweep tests and zeta potential analyses demonstrated conclusively that the rheological properties of the paste are significantly influenced by the addition of urea and CMC at various concentrations. Compression and tensile strengths were evaluated, and it was discovered that a higher CMC content positively affected interlayer adhesion along the printing direction, thereby increasing the compression and tensile strengths of the structures. Using the Fourier-transform infrared spectroscopy (FTIR), a comprehensive investigation of the chemical interactions between CNF, urea, and CMC was conducted. Consequently, this method provides an economically viable alternative for promoting sustainable nanomaterials in the field of additive manufacturing, thereby creating new opportunities for increasing production scale and efficiency

Evaluation of Pedestrian Level of Service of Selected Footpath Segments of Dhaka City Using Multi-criteria Decision Making Approach

Walking is considered to be the most important mode of travel across the world particularly for a shortdistance trip Since 19 6 of the trips are made by the foot in Dhaka it is necessary to ensure a friendly walking environment in the footpath for the welfare of pedestrians of Dhaka This study aims to make a comparative analysis of Pedestrian Level of Service PLOS of selected footpath segments along Segun Bagicha road Toynbee Circular Road Mirpur Road and Baily road Pedestrian Level of Service has been determined based on ten factors path width pedestrian volume crossing facilities availability of buffer distance from vehicular traffic surface quality comfort walking environment the existence of street light The weight of each factor has been determined through the Multi-criteria analysis approach Analytical Hierarchy Process Path width Pedestrian volume and the existence of buffer are the first second and third most important factors PLOS has been determined based on the indexed value of factors and weight of factors All the sections were found to have poor PLOS The findings of the study will be helpful for transport policymakers to improve the condition of these factors to ensure a better walking condition for pedestrians of selected footpath section

Tools and Techniques Adapted for Teaching Software Engineering Topics Remotely during the COVID-19 Pandemic

To stop the spread of the COVID-19 virus, educational institutions abruptly switched from in-person to online, remote mode of teaching without giving educators the necessary tools and training. In this paper, we focus on the Software Engineering Education & Training (SEET) courses at the university levels and address questions like: What tools and techniques did they adapt to handle the modality transition challenges? What lessons they learned and what would they do differently the next time? What are the students' perspective on these, etc.? We interviewed 16 SEET educators from different countries around the world; followed by surveys of more than 300 educator and student participants. Our empirical study found some common themes of challenges, as well as suggestions on tools and techniques to overcome them

Development of an enhanced analytical method utilizing pepper matrix as an analyte protectant for sensitive GC-MS/MS detection of dimethipin in animal-based food products

Herein, an analytical method using gas chromatography-tandem mass spectrometry (GC- MS/MS) was devised to detect the presence of the troublesome pesticide dimethipin in various animal-based food products, including chicken, pork, beef, eggs, and milk. The injection port was primed with a matrix derived from pepper leaves that acts as an analyte protectant (AP) to safeguard the target compound from thermal degradation during gas chromatography. The presence of AP resulted in a remarkable limit of quantification of 0.005 mg/kg for dimethipin in five matrices. Three different versions (original, EN, and AOAC) of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method were compared for dimethipin extraction, with a double-layer solid-phase extraction (SPE) cartridge utilized for matrix purification. A seven-point external calibration curve was established for dimethipin in the five matrices, demonstrating excellent linearity with determination coefficients (R2) ≥ 0.998. The developed quantitative method was validated by fortifying each matrix with three different concentrations of standard dimethipin, and the average recovery fell within the acceptable range outlined in the CODEX guidelines (ranging from 88.8% to 110.0%), with a relative standard deviation (RSD) of ≤ 11.97%. This method effectively addresses the challenge of analyzing dimethipin and can therefore be used as a routine monitoring tool for dimethipin across various matrices

Phenotyping of mungbean (Vigna radiata L.) genotypes against salt stress and assessment of variability for yield and yield attributing traits

Salt tolerance is a complex polygenic trait that is genotype specific and tolerance can depend upon a plants developmental stage. To evaluate reproductive stage specific salt tolerance as well as investigate the inherent variability of mungbean (Vigna radiata L.) genotypes with respect to seed yields and yield-related traits, a pot culture experiment was conducted using 26 mungbean genotypes and exposure to salt stress (EC = 8.0 dS/m) applied at the reproductive stage, just before the opening of the first flowers. The experiment involved maintaining 100% field capacity for three weeks and used a randomized complete block design with three replicates. Data were collected, included days to maturity, plant height (cm), number of pod-bearing branches per plant, number of pods per plant, pod length (cm), number of seeds per pod, 100-seed weight (g) and seed yield per plant (g). Salt stress led to a significant (p<0.001) decrease in seed yield per plant, with yields of the genotypes BMX 11116, BMX 11176, BMX 11140, BMX 11111 and BMX 11163 being the least impacted by exposure to salt. Principal component analysis revealed that the first two components explained 63.5% of the total variation among the mungbean genotypes. Seed yield per plant showed a significant positive correlation with days to maturity, number of pod-bearing branches per plant, number of pods per plant, pod length (cm), number of seeds per pod, and 100-seed weight (g). Cluster analysis grouped the 26 genotypes into five distinct clusters, where the tolerant genotypes placed in cluster I. Based on their stress tolerance indices BARI Mung-6, BMX 11176, BMX 11116, and BMX 11140 were categorized as tolerant genotypes, were selected for further study under direct field conditions and are recommended for the genetic improvement of salt stress tolerance in mungbean

Modelling and Forecasting the Consumer Price Index in Bangladesh through Econometric Models

Persistent economic growth along with high Consumer Price Index (CPI) and low inflation is the major aim of the economic theory. This paper uses annual time series data on CPI from the period 1986 to 2018 and find the best econometric time series model for forecasting the CPI in Bangladesh. In this study different Autoregressive integrated moving average (ARIMA) model are used. To find the best ARIMA model we have used here Akaike information criteria (AIC), corrected Akaike information criteria (AICc) and Bayesian information criteria (BIC). This study presents ARIMA (2, 2, 0) model to forecast the CPI in Bangladesh based on the lowest values of AIC, AICc and BIC than other ARIMA models. Based on the selected ARIMA (2, 2, 0) model we forecast the CPI in Bangladesh from period 2019 to 2025. The results of the study show that the CPI in Bangladesh is to continue an upward trend with respect to time

Comparison Between Reduced Susceptibility to Disinfectants and Multidrug Resistance Among Hospital Isolates of Pseudomonas aeruginosa and Staphylococcus aureus in Bangladesh

Disinfectants have been used largely in hospitals, health care centers and different pharmaceuticals for the removal of microorganisms. It is evident that microorganisms are showing reduced sensitivity against many disinfectants or their minimum inhibitory concentration (MIC) is increasing day by day due to improper use. The aim of this study was to compare the reduced susceptibility to disinfectants and antibiotics of 25 hospital isolates of Pseudomonas aeruginosa and 40 hospital isolates of Staphylococcus aureus isolated from 5 different hospitals at Noakhali region of Bangladesh. Susceptibility of the selected isolates to two disinfectants (savlon and herpic) and ten separate antimicrobial agents for both P. aeruginosa and S. aureus were investigated and compared. Multidrug resistant pattern of all the hospital isolates were determined by agar diffusion method and MIC of the disinfectants were determined by the serial dilution method. All the hospital isolates of P. aeruginosa and S. aureus were multidrug resistant. No severe evident resistance to disinfectants was seen among the 25 isolates of P. aeruginosa and 40 isolates of S. aureus. Interestingly, satisfactory MIC of savlon for 25 isolates of P. aeruginosa and 40 isolates of S. aureus reached at 0.5% to 0.7% (v/v) solution whereas satisfactory MIC of herpic reached at 2% to 2.5% (v/v) solution for all hospital isolates but four isolates of S. aureus showed MIC against herpic at 1.75% (v/v) solution. No sign of co-resistant of disinfectant and antibiotics were found. So, it can be concluded that disinfectants (savlon and herpic) can’t be responsible for P. aeruginosa and S. aureus to become multidrug resistant, when the semi inhibitory dilution of these disinfectants are used

Potential determinants of salinity tolerance in rice (Oryza sativa L.) and modulation of tolerance by exogenous ascorbic acid application

Rice is a relatively salt-sensitive crop with the reproductive and seedling stages being the most sensitive. Two separate experiments were conducted to isolate potential determinants of salinity tolerance and to investigate the possibility of modulating salt tolerance by exogenous ascorbic acid (AsA) application. Rice plants were imposed to salinity (EC= 10.0 dS m-1) both at the seedling and reproductive phases of growth. Salinity at the seedling stage resulted a sharp decline in shoot and root growth related traits including leaf chlorophyll content, while hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels increased. Plants experienced with salinity at the reproductive phases of growth showed a significant reduction in yield attributing traits while the tissue levels of H2O2 increased. Exogenous AsA application reversed the negative impact of salt stress, modulating the root and shoots growth and yield related traits and lowering H2O2 and MDA levels. FL-478 was identified as the most tolerant genotype at the seedling stage, with Binadhan-10 being the most tolerant at the reproductive stage. Grain yield panicle-1 significantly and positively corrected with number of filled grains panicle-1, panicle length, plant height, and spikelet fertility, and negatively correlated with H2O2 levels. Stress tolerance indices clearly separated the tolerant and susceptible genotypes. A principal component analysis revealed that the first two components explained 87% of the total variation among the genotypes. Breeding efforts could therefore to undertake for developing salinity tolerance by manipulating endogenous AsA content in rice