Recovery and reuse of chromium from tannery wastewaters using Turbinaria ornata seaweed

Brown seaweed (Turbinaria spp) was pre‐treated with sulfuric acid, calcium chloride and magnesium chloride and tested for its ability to remove chromium from tannery wastewater. Protonated seaweeds gave better uptake of chromium compared with calcium and magnesium treatments. Chromium uptake was optimal at pH 3.5. Turbinaria weed exhibited maximum uptake of about 31 mg of chromium for one gram of seaweed at an initial concentration of 1000 ppm of chromium. Freundlich and Langmuir adsorption isotherm models were used to describe the biosorption of chromium(III) by Turbinaria spp. The chromium‐loaded seaweed was reused as a reductant in the preparation of the tanning agent basic chromium sulfate (BCS). Leathers made from this tanning agent had properties comparable to conventionally processed chrome‐tanned leathers. Copyright © 2004 Society of Chemical Industry     

Processing and Characterisation of Epoxy–SiC Functionally Graded Polymer Matrix Composites

This paper proposed preparing and investigating the Epoxy–Silicon carbide composite for aerospace applications. In recent years aerospace industries concentrated in low weight, high strength and high thermal resistance materials. Polymer matrix composite can provide a better solution for the statement mentioned above. This study thermosetting study Epoxy and SiC materials have mixed in centrifugal casting with the ratio of 5%-SiC and resin. The microstructural evaluation is carried by Scanning Electron microscopic and investigating the tensile and hardness properties of the Epoxy– SiC Functionally Graded Polymer Matrix Composites. The wear and fracture analyse were investigated, and the results were discussed. the results show the SiC has provided the higher strength for composite, and its mixing percentage has control the weight of the polymer composite.

     

Investigation of liquid crystalline and photocrosslinkable poly[4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamate]s

Three series of liquid‐crystalline‐cum‐photocrosslinkable polymers were synthesized from 4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamates (x = ? H, ? OCH₃ and ? CN; m = 6, 8 and 10) by free radical solution polymerization using azobisisobutyronitrile as an initiator in tetrahydrofuran at 60 °C. All the monomers and polymers were characterized using intrinsic viscosity, and FTIR, ¹H NMR and ¹³C NMR spectroscopy. The liquid crystalline behavior of these polymers was examined using a hot stage optical polarizing microscope. All the polymers exhibited liquid crystalline behavior. The hexamethylene spacer‐containing polymers exhibited grainy textures; in contrast, the octamethylene and decamethylene spacer‐containing polymers showed nematic textures. Differential scanning calorimetry data confirmed the liquid crystalline property of the polymers. Thermogravimetric analysis revealed that all the polymers were stable between 236 and 344 °C in nitrogen atmosphere and underwent degradation thereafter. As the methylene chain length increases in the polymer side‐chain, the thermal stability and char yield of the polymers decrease. The photocrosslinking property of the polymers was investigated using the technique of exposing the polymer solution to UV light and using UV spectroscopy. The crosslinking reaction proceeds via 2π–2π cycloaddition reactions of the ? CH?CH? of the pendant cinnamate ester. The polymers containing electron‐releasing substituents (? OCH₃) showed faster crosslinking than the unsubstituted polymers and those containing electron‐withdrawing substituents (? CN). Copyright © 2007 Society of Chemical Industry     

Long term soft tissue response to metals,ceramics and composites—a comparative histopathological evaluation

Soft tissue reaction to metals, ceramics and composites was investigated over a long period. Titanium, nitrided titanium, ruby, sapphire and carbon-carbon composite materials were used. Histological response was uniform for all materials despite their differing chemical and physical properties.     

Morphological and chromosomal descriptions of new species in the Anopheles subpictus complex

In the present work, the role of lipid peroxidation in cellular lethal injury induced by various types of oxidative stress has been studied in both normal and tumor thymocytes. The prooxidants included either a xanthine/xanthine oxidase system, which is an exogenous source of oxyradicals, or tert-butyl hydroperoxide (t-BOOH), which enters the cell and endogenously produces free radicals. Our data demonstrate that: (A) Using xanthine/xanthine oxidase system as a prooxidant, normal thymocytes are more sensitive than thymoma cells to oxidative damage, as their lactate dehydrogenase (LDH) and malondialdehyde (MDA) release is higher than that of tumor cells. By varying Fe3+/ADP ratios, a positive correlation can be established between LDH and MDA release only in normal thymocytes. While thymoma cells still show a very high level of vitamin E (80%) after 15 min of incubation with this prooxidant, normal thymocytes lose it after the same incubation time. (B) Using t-BOOH as a prooxidant, normal thymocytes release a higher amount of MDA but a lower amount of LDH than thymoma cells. In agreement with the results obtained with the xanthine/xanthine oxidase system, by varying the concentrations of the prooxidant, a correlation between LDH and MDA release can be established only in normal thymocytes. Although high levels of the antioxidant are still present in both kinds of cells after 15 min of incubation with t-BOOH, normal thymocytes consume vitamin E faster than thymoma cells. These data suggest that the role of lipid peroxidation in cell lethal injury is influenced by the source and the site of radical production as well as by the cell type. With t-BOOH as a prooxidant in normal thymocytes, lipid peroxidation is only partially involved in the induction of irreversible cell injury, but it plays a crucial role when the xanthine/xanthine oxidase system is used as a prooxidant. Moreover, whatever the prooxidant used in tumor thymocytes, membranes are more resistant to lipid peroxidation, suggesting that this mechanism is not causally related to cell death.     

Hydrogel microspheres from crosslinked poly(methyl methacrylate): synthesis and biocompatibility studies

Smooth, perfectly spherical, highly hydrophilic microspheres have been prepared from crosslinked poly(methyl methacrylate) microspheres by alkaline hydrolysis in ethylene glycol at elevated temperatures. These microspheres absorb varying quantities of water depending upon the extent of hydrolysis. Subcutaneous implantation studies on rabbits demonstrated that the microspheres are biocompatible. Implantation studies in the renal arteries of dogs demonstrated the occlusion effect produced by the microspheres. Microspheres could be made radiopaque by the incorporation of barium sulphate. Potential uses envisaged for these microspheres in the biomedical area are that of artificial emboli for endovascular embolization and as microcarriers for the growth and propagation of anchorage dependent mammalian cells.     

Self-adaptable media service architecture for guaranteeing reliable multimedia services

The main objective of this paper is to design and develop a Self-Adaptable Media Service Architecture (SAMSA) for providing reliable dynamic composite multimedia service through policy-based actions. The multimedia services such as media retrieval, transcoding, scaling and display services are combined based on the preferences of the user to create a dynamic composite multimedia service called as Video-on-Demand service. Such distributed multimedia services deployed using Service Oriented Architecture (SOA) can be accessed in heterogeneous environments that are prone to changes during run-time. To provide reliable and adaptive multimedia services, a powerful self-adaptable architecture with dynamic compositions of multimedia services is necessary to adapt during run-time and react to the environment. The adaptability in this proposed architecture is achieved by enabling the service providers to Monitor, Analyze and Act on the defined policies that support customization of compositions of multimedia services and guarantee the Quality of Service (QoS) provisioning. The Media Service Monitor (MSM) observes the business and quality metrics associated with the multimedia services during run-time. The monitored results are analyzed by Monitored Results Analyzer (MRA) which identifies the type and location of the fault. The Adaptive Media Service Manager (AMSM) takes corrective actions based on the monitored results, through the policies defined as an extension of WS-Policy (Web Service—Policy framework). The effectiveness of the proposed Self-Adaptable Media Service Architecture (SAMSA) has been evaluated on Dynamic Composite Real-time Video-on-Demand Web Service (DCRVoDWS) for a maximum of 200 simultaneous client’s requests. The analysis of results shows that the proposed architecture provides better improvement on reliability, response time and user satisfaction.     

Preconditioned Bayesian Regression for Stochastic Chemical Kinetics

We develop a preconditioned Bayesian regression method that enables sparse polynomial chaos representations of noisy outputs for stochastic chemical systems with uncertain reaction rates. The approach is based on the definition of an appropriate multiscale transformation of the state variables coupled with a Bayesian regression formalism. This enables efficient and robust recovery of both the transient dynamics and the corresponding noise levels. Implementation of the present approach is illustrated through applications to a stochastic Michaelis–Menten dynamics and a higher dimensional example involving a genetic positive feedback loop. In all cases, a stochastic simulation algorithm (SSA) is used to compute the system dynamics. Numerical experiments show that Bayesian preconditioning algorithms can simultaneously accommodate large noise levels and large variability with uncertain parameters, and that robust estimates can be obtained with a small number of SSA realizations.     

Biogenic gold nanoparticles for reduction of 4‐nitrophenol to 4‐aminophenol: an eco‐friendly bioremediation

The present study investigated the synthesis of gold nanoparticles (AuNPs) using mangrove plant extract from Avicennia marina as bioreductant for eco‐friendly bioremediation of 4‐nitrophenol (4‐NP). The AuNPs synthesised were confirmed by UV spectrum, transmission electron microscopy (TEM), X‐ray diffraction, Fourier transmission infrared spectroscopy (FTIR), dynamic light scattering (DLS), and zeta potential. The AuNPs were found to be spherical in shape with size ranging from 4 to 13 nm, as evident by TEM and DLS. Further, the AuNPs were encapsulated with sodium alginate in the form of gold nano beads and used as heterogeneous catalyst and degrading agent to reduce 4‐NP. This reduction in 4‐NP into 4‐aminophenol was confirmed by UV and FTIR. The aqueous solution of 4‐NP peaked its absorbance at 320 nm, and shifted to 400 nm, with an intense yellow colour, appeared due to formation of 4‐nitrophenolate ion. After the addition of AuNps, the 4‐NP solution became colourless and peaked at 400 nm and reduced to 290 nm corresponding to the formation of 4‐aminophenol. Hence, the present work suggested the AuNPs as the potent, eco‐friendly bionanocomposite catalyst for bioremediation of 4‐NP.Inspec keywords: gold, nanoparticles, nanobiotechnology, nanofabrication, ultraviolet spectra, transmission electron microscopy, X‐ray diffraction, Fourier transform spectra, infrared spectra, electrokinetic effects, catalysts, nanocomposites, biochemistryOther keywords: biogenic gold nanoparticles, 4‐nitrophenol, 4‐aminophenol, eco‐friendly bioremediation, mangrove plant extract, Avicennia marina, bioreductant, UV spectrum, transmission electron microscopy, TEM, X‐ray diffraction, Fourier transmission infrared spectroscopy, FTIR, dynamic light scattering, DLS, zeta potential, degrading agent, 4‐nitrophenolate, bionanocomposite catalyst, size 4 nm to 13 nm, wavelength 400 nm, wavelength 290 nm, Au     

Cutting Edge Use of Conductive Patterns in Nanocellulose-Based Green Electronics

Green electronics made from degradable materials have recently attracted special attention, because electronic waste (e-waste) represents a serious threat to the environment and to human health worldwide. Among the novel materials used for sustainable technologies, nanocelluloses containing at least 1D in the nanoscale range (1–100 nm) have been widely exploited for various industrial applications owing to their inherent properties, such as biodegradability, mechanical strength, thermal stability, and optical transparency. This review highlights recent advances in research on the development of patterns for conductive material on nanocellulose substrates for use in high-performance green electronics. The advantages of nanocellulose substrates compared to conventional paper substrates for advanced green electronics are discussed. Importantly, this review emphasizes various fabrication strategies for producing conductive patterns on different types of nanocellulose-based substrates, such as cellulose nanofiber (CNF), (2,2,6,6-tetramethylpiperidin-1-yl)oxyl(TEMPO)-oxidized CNF, regenerated cellulose, and bacterial cellulose. In the latter part of this review, emerging engineering applications for green electronics such as circuits, transistors/antennas, sensors, energy storage systems, and electrochromic devices are further discussed.