Numerical studies on heat and fluid flow of nanofluid in a partially heated vertical annulus

A numerical investigation on natural convective heat transfer of nanofluid (Al₂O₃+water) inside a partially heated vertical annulus of high aspect ratio (352) has been carried out. The computational fluid dynamics solver Ansys Fluent is used for simulation and results are presented for various volume fraction of nanoparticles (0‐0.04) at different heat flux values (3‐12 kW/m²). Two well‐known correlations for evaluating thermal conductivity and viscosity have been used. Thus different combinations of the available correlations have been set to form four models (I, II, III, and IV). Therefore, a detailed analysis has been executed to identify effects of thermophysical properties on heat transfer and fluid flow of nanofluids using different models. The results show enhancement in heat transfer coefficient with volume fraction of nanoparticles. Highest enhancement achieved is found to be 14.17% based on model III, while the minimum is around 7.27% based on model II. Dispersion of nanoparticles in base fluid declines the Nusselt number and Reynolds number with different rates depending on various models. A generalized correlation is proposed for Nusselt number of nanofluids in the annulus in terms of volume fraction of nanoparticles, Rayleigh number, Reynolds number, and Prandtl number.     

Optimizing distortion for real‐time data gathering in randomly deployed sensor networks

In several wireless sensor network applications, it is required to perform real‐time reconstruction of the data field being sensed by the network. This task is generally carried out at a central location, e.g. sink node, using a continuous data gathering phase and relying on the known correlation properties of the underlying data field. Estimating the overall spatial and temporal distortion in the reconstructed field is an important step toward deciding the number of sensors to be deployed and the data collection algorithm to be used. However, estimating distortion in arbitrary networks is a challenging task. Existing work has focused on regular network deployments such as one‐ and two‐dimensional girds. Such deployments are deemed infeasible in a realistic environment. In this paper, we consider one‐ and two‐dimensional random networks. For the analysis purposes, we assume that the nodes are randomly deployed following Poisson distribution. We determine the total distortion function given the correlation coefficients of the field while assuming a simple data gathering protocol. Based on this, we also determine the optimal number of nodes to be deployed in the field that will minimize distortion. Copyright © 2009 John Wiley & Sons, Ltd.     

Scalability of 2-D wavelet transform algorithms: analytical and experimental results on MPPs

This paper studies the scalability of two-dimensional (2-D) discrete wavelet transform (DWT) algorithms on massively parallel processors (MPPs). The principal operation in the 2-D DWT is the filtering operation used to implement the filter banks of the 2-D subband decomposition. This filtering operation can be implemented as a convolution in the time domain or as a multiplication in the frequency domain. We demonstrate that there exist combinations of machine size, image size, and wavelet kernel size for which the time-domain algorithms outperform the frequency domain algorithms and vice-versa. We therefore demonstrate that a hybrid approach that combines time- and frequency-domain approaches can yield linear scalability for a broad range of problem and machine sizes. Furthermore, we show the effect of processor speed versus communication overhead and the use of separable versus nonseparable wavelets on the crossover points between the algorithm approaches.     

Clozapine Increases Nestin Concentration in the Adult Male Rat Hippocampus: A Preliminary Study

Patients with schizophrenia, and rodent models of the disease, both exhibit suppressed neurogenesis, with antipsychotics possibly enhancing neurogenesis in pre-clinical models. Nestin, a cytoskeletal protein, is implicated in neuronal differentiation and adult neurogenesis. We hypothesized that schizophrenia pathogenesis involves nestin downregulation; however, few studies have related nestin to schizophrenia. We assessed nestin protein concentration, prepulse inhibition (PPI), and social interaction in the MK-801 model of schizophrenia, with or without antipsychotic (clozapine) treatment. Adult male Sprague–Dawley rats were intraperitoneally administered saline or MK-801 (0.1 mg/kg) to produce a schizophrenia-like phenotype, with concomitant subcutaneous injections of vehicle or clozapine (5 mg/kg). PPI was assessed on days 1, 8, and 15, and social interaction was assessed on day 4. Hippocampus tissue samples were dissected for Western blotting of nestin concentration. MK-801 alone did not alter nestin concentration, while clozapine alone enhanced hippocampal nestin concentration; this effect was not apparent in animals with MK-801 and clozapine co-administration. MK-801 also produced schizophrenia-like PPI disruptions, some of which were reversed by clozapine. Social interaction deficits were not detected in this model. This is the first report of clozapine-induced enhancements of hippocampal nestin concentration that might be mediated by NMDA receptors. Future studies will explore the impact of neurodevelopmental nestin concentration on symptom onset and antipsychotic treatment.     

Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.     

C: A Parallel Model for Coarse-Grained Machines

In this paper, we propose a model for parallel computation, the C³-model. The C³-model evaluates, for a given parallel algorithm and target architecture, the complexity ofcomputation, the pattern ofcommunication, and the potentialcongestionarising during communication. A metric for estimating the effect of link and processor congestion on the performance of a communication operation is developed. This metric allows the evaluation of arbitrary communication operations without the user having to specify fine scheduling details. We describe how the C³-model can serve as a platform for the development of coarse-grained algorithms sensitive to the parameters of a parallel machine. The initial validation of the C³-model is discussed for the Intel Touchstone Delta. We compare predicted and actual performance of different solutions for communication operations and of various divide-and-conquer approaches for contour ranking on images.     

Surfaces modification of methylcellulose: Cobalt nitrate polymer electrolyte by sulfurated hydrogen gas treatment

This article discusses the surface modification of methylcellulose:nitrate cobalt [MC:Co(NO₃)₂] through the sulfurated hydrogen (H₂S) gas treatment. Solution cast technique has been used to fabricate MC:Co(NO₃)₂‐based solid polymer electrolytes. The results achieved for structural, morphological and optical properties indicate that H₂S gas treatment is crucial for modification of polymer electrolytes to polymer composites. The morphological appearance revealed that the H₂S gas treatment produced cobalt sulfide (CoS) nanoparticles on the surface of the films. The results of X‐ray diffraction indicate the disruption of the crystalline phase of the MC polymer upon addition of various amounts of Co(NO₃)₂ salt. The optical absorption spectra of the electrolyte samples shifted to higher wavelengths with increasing the cobalt nitrate salt concentration. The optical band gap of MC incorporated with 40 wt % Co(NO₃)₂ concentration was 4.69 and reduced to 4.52 eV after H₂S surface treatment. The linear relationship between the refractive index and salt concentration supports the uniform distribution of the developed nanoparticles appeared in STM images. The significant change in intensity and position of Fourier transform infrared transmittance bands is an evidence for the formation of charge transfer complex between the added salt and the MC host polymer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46676.     

Synthesis,characterisation and potential applications of polyaniline/chitosan‐Ag‐nano‐biocomposite

Biodegradable polymers have greatly promoted the development of environmental, biomedical and allied sciences because of their biocompatibility and doping chemistry. The emergence of nanotechnology has envisaged greater options for the development of biodegradable materials. Polyaniline grafted chitosan (i.e. biodegradable PANI) copolymer was prepared by the chemical in situ polymerisation of aniline using ammonium per sulphate as initiator while Ag nanoparticle were synthesised by chemical reduction method and incorporated in to the polymer matrix. The as prepared materials were characterised by X‐ray diffraction, Fourier transform Infra‐red spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis. Moreover energy storage capacity, impedance properties were also studied. The main focus was on the photocatalytic degradation of organic dyes to remove the toxic and carcinogenic pollutants. This polymer nano‐biocomposite has multifold applications and can be used as excellent materials for enhanced photodegradation and removal of toxic contaminants from waste waters and natural water streams. In addition, the biocompatible materials with excellent mechanical properties and low toxicity can also be used for tissue engineering, drug delivery and electrical energy storage devices.Inspec keywords: silver, filled polymers, polymer blends, nanocomposites, nanoparticles, nanofabrication, biodegradable materials, polymerisation, reduction (chemical), Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, X‐ray diffractionOther keywords: polyaniline‐chitosan‐silver‐nanobiocomposite, biodegradable polymers, biocompatibility, doping chemistry, nanotechnology, biodegradable PANI, polyaniline grafted chitosan copolymer, biodegradable materials, chemical in situ polymerisation, nanoparticle, polymer matrix, chemical reduction method, Fourier transform Infrared spectroscopy, transmission electron microscopy, energy dispersive X‐ray analysis, X‐ray diffraction, energy storage capacity, impedance properties, carcinogenic pollutants, toxic pollutants, photodegradation, toxic contaminants, natural water streams, waste waters, drug delivery, tissue engineering, electrical energy storage devices, mechanical properties, Ag     

Derivatization of keto fatty acids: V. Synthesis and characterization of 1,3-dioxolanes

The synthesis of substituted 1,3-dioxolanes from oxo fatty acid esters using 1,2-propanediol is described. This reagent, besides forming dioxolanes, also converts the methyl ester to the 2′-hydroxy propyl ester. Methyl 10-oxoundecanoate gives 2′-hydroxy propyl 10-(2″-methyl ethylene dioxolane) undecanoate (Ia, 75%) as a major product. Methyl 9-oxooctadecanoate reacts similarly and yields 2′-hydroxy propyl 9-(2″-methyl ethylene dioxolane) octadecanoate (IIb, 60%), along with the minor products (IIa, IIc). Methyl 2-oxooctadecanoate, after prolonged refluxing, affords only 2′-hydroxy propyl 2-(2″-methyl ethylene dioxolane) octadecanoate (IIIa) in 70% yield. Structures of each reaction product were established on the basis of elemental analysis, IR, NMR and a study of mass spectrometry.     

A relational database of protein structures designed for flexible enquiries about conformation

A relational database of protein structure has been developedto enable rapid and flexible enquiries about the occurrenceof many aspects of protein architecture. The coordinates of294 proteins from the Brookhaven Data Bank have been processedby standard computer programs to generate many additional termsthat quantify aspects of protein structure. These terms includesolvent accessibility, main-chain and side-chain dihedral angles,and secondary structure. In a relational database, the informationis stored in tables with columns holding the different termsand rows holding the different entries for the terms. The differentrelational base tables store the information about the proteincoordinate set, the different chains in the protein, the aminoacid residues and ligands, the atomic coordinates, the saltbridges, the hydrogen bonds, the disulphide bridges and theclose tertiary contacts. The database was established underORACLE management system. Enquiries are constructed in ORACLEusing SQL (structured query language) which is simple to useand alleviates the need for extensive computer programs. A singletable can be searched for entries that meet various criteria,e.g. all protein solved to better than a given resolution. Thepower of the database occurs when several tables, or the entriesin a single table, are cross-correlated. For example the dihedralangles of proline in the fourth position in an -helix in highresolution structures can be rapidly obtained. The structuraldatabase provides a powerful tool to obtain empirical rulesabout protein conformation. This database of protein structuresis part of a joint project between Birkbeck College and LeedsUniversity to establish an integrated data resource of proteinsequences and structures (ISIS) that encodes the complex patternsof residues and coordinates that define protein conformation.The entire data resource (ISIS) will provide a system to guideall areas of protein modelling including structure prediction,site-directed mutagenesis and de novo protein design. The availabilityof ISIS is described in the paper.