Preparation and characterization of cellulose-based nanocomposite hydrogel films containing CuO/Cu2O/Cu with antibacterial activity

In the present study, the influence of citric acid (CA) on hydrogel films composed of sodium carboxymethylcellulose (NaCMC), hydroxypropylmethylcellulose (HPMC), and CuO nanoflakes was investigated for their physicochemical, mechanical, thermal, and antibacterial properties. XRD patterns showed that the prepared hydrogel films revealed the crystalline phase for CuO/Cu₂O/Cu at 20% CA concentration. Laser micro-Raman spectroscopy confirmed the presence of CuO and Cu₂O in the films. Increase in CA concentration decreased the swelling degree and tensile strength and increased the decomposition temperature of NaCMC, HPMC, and CuO. According to FESEM and FETEM results, shape and size of CuO nanoflakes were completely changed into spherical nanoparticles with increase in CA concentration. HRTEM and inverse Fourier transform images showed that the d-spacing of CuO, Cu₂O, and Cu were correlated with XRD results. The prepared hydrogel films exhibited significant antibacterial activity and biocompatibility against HaCaT cells. All these data recommend that the prepared hydrogel films may be used for potential wound healing applications.     

Expanded graphene-oxide encapsulated polyaniline composites as sensing material for volatile organic compounds

The expanded graphene-oxide (EGO) encapsulated PA composite materials are prepared by in-situ chemical oxidative polymerisation polyaniline (PA) where polymerization of aniline was carried out in presence of EGO using ammonium-persulphate in an acid medium. The synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrical conductivity measurements. The electrical conductivity get increases with temperature showing semiconducting behaviour and the conductivity is found to be 101.04 S/m at 413 K. The composite materials are exposed with various concentrations of vapours of different volatile organic compounds (VOCs) such as acetone, chloroform and carbon tetrachloride and compared with the pristine polymer. The oxidising VOCs like acetone on exposure to pristine polymer and PA/EGO composite is found to be decrease in resistivity by hydrogen bonding with the redox cites of the polymer. Among these VOCs, the sensitivity towards chloroform is found to be more in PA and its composites than the other two compounds.     

Sol–Gel Synthesis of MoO3/SiO2 Composite for Catalytic Application in Condensation of Anisole with Paraformaldehyde

MoO₃/SiO₂ composite with varying amounts of MoO₃ loading (1–20 wt.%) were prepared by sol–gel method and calcined at 500 °C. These catalysts were employed for the liquid phase condensation of anisole with paraformaldehyde. All the catalysts were characterized by N₂ sorption, XRD, and NH₃-TPD. The activities of synthesized MoO₃/SiO₂ catalysts were compared with p-toluene sulfonic acid (p-TSA), the most frequently used catalyst for the condensation reactions, and with a supported metal oxide (WO _x /ZrO₂). Under the similar reaction conditions, synthesized 10 wt.% MoO₃/SiO₂ catalyst calcined at 500 °C was found to be the most active in the condensation of anisole with paraformaldehyde.     

Concurrent optimisation of a computer vision system’s multiple responses

A number of recent research works have focused on how to improve the performance of production systems. This paper examines the system based on a simulation model with two manufacturing cells under a re-entrant environment. With the model a set of experiments has been carried out to study how the factors influence the system performance. Different release times and lot sizes have been compared, and scheduling heuristics for both bottleneck and non-bottleneck have been discussed to capture the essence of the production system. We used ANOVA to analyze the experimental results and achieved the conclusions that: interval releasing is better than beginning releasing; lot size can improve one of the performance indicators, but deteriorate the other under interval releasing; NC policy can obtain both good due-date performance and high throughput.     

EXPLORING PEN-BASED COMPUTER TECHNOLOGY

Some industry analysts believe that the impact of pen-based computers—also referred to as notepad or stylus computers and electronic slates—rivals that of desktop machines. This column describes how pen-based computers work and offers some suggestions for IS managers who want to implement pen-based computers into the current work environment.     

Chemical characterisation of CTC black tea of northeast India: correlation of quality parameters with tea tasters' evaluation

BACKGROUND: Consumers have different regional perceptions of tea quality. Objective evaluation based on biochemical data for different regions has been needed for a long time. Biochemical factors regulating this variation would help to remove regional disparities. This study was undertaken on CTC (crust, tear and curl) black tea to generate the biochemical data responsible for quality along with tea tasters' evaluation of three geographical regions of northeast India and to determine the reason for the variation. RESULTS: Brahmaputra valley teas had highest theaflavin (TF), thearubigin (TR), brightness (BR) and total colour (TC) and low crude fibre content (CFC) and total polyphenol (TPP). Brahmaputra valley and Dooars region teas showed high total soluble solid (TSS). Barak valley teas had highest CFC and low TSS, caffeine (CA), TF, TR and TC. Dooars region teas had high CA and TPP and low BR. Dooars region and Barak valley teas contained higher levels of residual catechin than Brahmaputra valley teas. CONCLUSION: Overall quality as evaluated by tea tasters was found to be highest for Brahmaputra valley teas followed by Dooars region and Barak valley teas. This high evaluation can be attributed to higher levels of TF, TR, BR and TSS. Barak valley and Dooars region teas contained high residual catechin, indicating limitation in oxidation during processing. Copyright © 2009 Society of Chemical Industry     

GPU-based Acceleration of System-level Design Tasks

Many system-level design tasks (e.g., high-level timing analysis, hardware/software partitioning and design space exploration) involve computational kernels that are intractable (usually NP-hard). As a result, they involve high running times even for mid-sized problems. In this paper we explore the possibility of using commodity graphics processing units (GPUs) to accelerate such tasks that commonly arise in the electronic design automation (EDA) domain. We demonstrate this idea via two detailed case studies. The first explores the possibility of using GPUs to speedup standard schedulability analysis problems. The second proposes a GPU-based engine for a general hardware/software design space exploration problem. Not only do these problems commonly arise in the embedded systems domain, their computational kernels turn out to be variants of a combinatorial optimization problem—viz., the knapsack problem—that lies at the heart of several EDA applications. Experimental results show that our GPU-based implementations offer very attractive speedups for the computational kernels (up to 100×), and speedups of up to 17× for the full problem. In contrast to ASIC/FPGA-based accelerators—given that even low-end desktop and notebook computers are now equipped with GPUs—our solution involves no extra hardware cost. Although recent research has shown the benefits of using GPUs for a variety of non-graphics applications (e.g., in databases and bioinformatics), harnessing the parallelism of GPUs to accelerate problems from the EDA domain has not been sufficiently explored so far. We believe that our results and the generality of the core problem that we address will motivate researchers from this community to explore the possibility of using GPUs for a wider variety of problems from the EDA domain.     

Investigation of mechanical factor of soil reinforced with four types of fibers: An integrated experimental and extreme learning machine approach

ABSTRACT

This study investigates and compares mechanical factor (a dimensionless parameter and defined as the ratio of the compressive strength of fiber reinforced soil to that of unreinforced soil) for soils reinforced with four different fibers (three natural fibers and one synthetic fiber). An integrated methodology was utilized, including 351 laboratory experiments for obtaining data and Extreme Learning Machine (ELM) technique for developing functional relationships between mechanical factor and soil and fiber parameters. Soils reinforced with synthetic fiber (Polypropylene) and with natural fibers exhibited different characteristics when subjected to the same variation in soil parameters. This phenomenon can be attributed to the differences in surface morphology and water absorption capability of Polypropylene comparative to other natural fibers. Polypropylene–soil composite shows the maximum sensitivity to the soil moisture. It also shows the least sensitivity toward soil density and fiber content among all tested fiber–soil composites.