A. H. M. Saadat

Preparation and Characterization of Starch/PVA Blend for Biodegradable Packaging Material

Polymer films of rice starch/Polyvinyl alcohol (PVA) were prepared by casting method. Different blends were made varying the concentration of rice starch and PVA. Tensile strength (TS) and elongation at break (Eb) of the prepared films were studied. Films made up of rice starch and PVA with a ratio of 2:8 showed highest TS. 10% sugar was added with highest TS giving four composition of Starch/PVA blend in order to increase TS and Eb. Films made up of rice starch and PVA and sugar with a ratio of 1:8:1 showed highest TS and Eb and the recorded value was 14.96MPa and 637% respectively. The physico-mechanical properties of the prepared sugar incorporated films were improved by grafting with acrylic monomer with the aid of UV radiation. A formulation was prepared with monomer, methylmethacrylat in methanol, and a photo initiator. The highest TS of the grafted films were recorded and the value was 16.38 MPa. The water uptake and weight loss in both soil and water of the grafted films are lower than the non-grafted films. The prepared films were further characterized with stereo micrograph and XRD. Finally, the produced film can be used as biodegradable packaging materials for shopping and garbage bags that are very popular and environment friendly.

Selection of minimum indicators of hydrologic alteration of the Gorai river, Bangladesh using principal component analysis

The use of a few indicators of hydrologic alteration can minimize statistical redundancy which can lead to take effective environmental flow management decisions. The aim of the research is to select representative dominant indicators of hydrological alteration through reducing the dimensionality of multivariate data for the Gorai river, Bangladesh. The required mean daily discharge data (1976–2006) of the Gorai have been collected from the Bangladesh Water Development Board. The Range of Variability Approach and anomaly of the river flow show hydrologic alteration in recent years comparing with past. Principal component analysis (PCA) in Kendall and Pearson methods has been performed by the XLSTAT software (version 2.9). Depending on eigenvalues (>1.0), seven and six Principal components (PCs) are selected for Kendall and Pearson methods, respectively, for further analysis. Since the eco-flow metrics of eco-deficit of the river has poor correlation with the indicators of hydrologic alteration, the resultant loadings are subjected to the Kaiser–Meyer–Olkin (KMO) Measure of Sampling Adequacy (MSA) method which is classified into marvelous, meritorious, middling, mediocre, and miserable based on the PC loading values. Seven indicators have been found whose PC loadings are in marvelous class and are common for both Kendall and Pearson methods. These indicators, named March mean flow, 1-day minimum mean, 3-day minimum mean, 7-day minimum mean, 30-day minimum mean, 90-day minimum mean, and 30-day maximum mean flows, are the desired indicators of hydrologic alteration of the Gorai river.