Computational fluid dynamic modeling of fluidized bed polymerization reactors

Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multifluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multifluid CFD model for gas-particle flow is based on the kinetic theory of granular flow closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor

Representing and reasoning with qualitative preferences for compositional systems

Many applications call for techniques for representing and reasoning about preferences, i.e., relative desirability over a set of alternatives. Preferences over the alternatives are typically derived from preferences with respect to the various attributes of the alternatives (e.g., a student\u27s preference for one course over another may be influenced by his preference for the topic, the time of the day when the course is offered, etc.). Such preferences are often qualitative and conditional. When the alternatives are expressed as tuples of valuations of the relevant attributes, preferences between alternatives can often be expressed in the form of (a) preferences over the values of each attribute, and (b) relative importance of certain attributes over others. An important problem in reasoning with multi-attribute qualitative preferences is dominance testing, i.e., to find if one alternative (assignment to all attributes) is preferred over another. This problem is hard (PSPACE-complete) in general for well known qualitative conditional preference languages such as TCP-nets. We provide two practical approaches to dominance testing. First, we study a restricted unconditional preference language, and provide a dominance relation that can be computed in polynomial time by evaluating the satisfiability of an appropriately constructed logic formula. Second, we show how to reduce dominance testing for TCP-nets to reachability analysis in an induced preference graph. We provide an encoding of TCP-nets in the form of a Kripke structure for CTL. We show how to compute dominance using NuSMV, a model checker for CTL. We address the problem of identifying a preferred outcome in a setting where the outcomes or alternatives to be compared are composite in nature (i.e., collections of components that satisfy certain functional requirements). We define a dominance relation that allows us to compare collections of objects in terms of preferences over attributes of the objects that make up the collection, and show that the dominance relation is a strict partial order under certain conditions. We provide algorithms that use this dominance relation to identify only (sound), all (complete), or at least one (weakly complete) of the most preferred collections. We establish some key properties of the dominance relation and analyze the quality of solutions produced by the algorithms. We present results of simulation experiments aimed at comparing the algorithms, and report interesting conjectures and results that were derived from our analysis. Finally, we show how the above formalism and algorithms can be used in preference-based service composition, substitution, and adaptation

Functional and radiological outcome of comminuted shaft of humerus fracture treated by dynamic compression plate

Background: Humeral shaft fractures represents between 3% and 5% of all fractures of which a certain number of patients require surgical intervention. This study aims to determine the efficacy of dynamic compression plate in the treatment of humeral shaft fractures.Methods: A prospective study was carried out over a period of 2 years in Sri Ramachandra Medical College, Chennai including 30 cases of shaft of humerus fractures treated by open reduction and internal fixation using Dynamic Compression plate among which both comminuted and segmental closed shaft of humerus fractures were included. While open fractures and ipsilateral forearm and clavicle fractures were excluded. AO classification was used to classify the fractures and the average follow up period was two years. The American Shoulder and Elbow Surgeons (ASES) shoulder score and Romen al series grading were used.Results: We had 93.3% excellent/good result and 6.7% poor results. In our series we had one non-union, one delayed union and one case of deep infection.Conclusions: Proper preoperative planning, minimal soft tissue dissection, strict asepsis, proper postoperative rehabilitation and patient education were essential to obtain excellent results. Early post-operative mobilization following rigid fixation of the fracture of humerus, with DCP lowered the incidence of stiffness and sudecks dystrophy

SMART HOME

The modern home automation system gives security & blissful life at residence. That is why popularity of using home automation technology is increasing day by day. The project aims in designing a system which makes operating of electrical appliances in home through Android mobile phone possible. The controlling of electrical appliances is done wirelessly through Android smart phone using the Bluetooth feature present in it. Here in this project the Android smart phone is used as a remote control for operating the electrical appliances. Android boasts a healthy array of connectivity options, including Wi-Fi, Bluetooth, and wireless data over a cellular connection (for example, GPRS, EDGE (Enhanced Data rates for GSM Evolution), and 3G). Android provides access to a wide range of useful libraries and tools that can be used to build rich applications. In addition, Android includes a full set of tools that have been built from the ground up alongside the platform providing developers with high productivity and deep insight into their applications. Bluetooth is an open standard specification for a radio frequency (RF)-based, short-range connectivity technology that promises to change the face of computing and wireless communication. It is designed to be an inexpensive, wireless networking system for all classes of portable devices, such as laptops, PDAs (personal digital assistants), and mobile phones. It also will enable wireless connections for desktop computers, making connections between monitors, printers, keyboards, and the CPU cable-free. We will be using Bluetooth in our project

A Retrospective Clinical Audit of Outcomes of Cochlear Implantation in Children with Multiple Disabilities in Comparison with Normal Implantees : A South Indian Experience

Open Access via Springer Compact Agreement We would like to thank the team and the Auditory Verbal Habilitationists at Madras ENT Research Foundation (MERF), Chennai for all their support during the course of this project. Special thanks to the Medical Statistics Team at the University of Aberdeen for additional advice on the data analysis.Peer reviewedPublisher PD

Effect of nitrate metal (Ce, Cu, Mn and Co) precursors for the total oxidation of carbon monoxide

The ambient temperature carbon monoxide oxidation is one of the important topics in the present scenario. In this paper, we prepared various types of catalysts from the precursors of cobalt nitrate, cerium nitrate, copper nitrate and manganese nitrate for the oxidation of CO. Among the prepared catalysts, the cerium nitrate precursor showed the best performance for CO oxidation at low temperature. The activity of the catalysts was measured in different calcination conditions like stagnant air, flowing air and reactive calcination (4.5% CO in air). The activity test was done in the reactor under the following reaction conditions: 100 mg of catalyst, 2.5% CO in the air and the reaction temperature was increased from ambient to a higher value at which complete oxidation of CO was achieved. The characterization of the catalyst was done by several techniques like XRD, FTIR, SEM-EDX, XPS and BET. The order of activity for different catalysts was as follows: Ce-Oxide > Mn-Oxide > Cu-Oxide > Co-Oxide

Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation

The hopcalite (CuMnOx) catalyst is a well-known catalyst for oxidation of CO at ambient temperature. It has prepared by co-precipitation method and the preparation parameters were like Copper/Manganese (Cu:Mn) molar ratios, drying temperature, drying time, calcination temperature and calcination time has an influence on activity of the resultant catalyst. The activity of the catalyst was measured in flowing air calcinations (FAC) conditions. The reaction temperature was increased from ambient to a higher value at which complete oxidation of CO was achieved. The particle size, weight of catalyst and CO flow rate in the air were also influenced by the activity of the catalyst for CO oxidation. The characterizations of the catalysts were done by several techniques like XRD, FTIR, BET, SEM-EDX and XPS. These results were interpreted in terms of the structure of the active catalyst. The main aim of this paper was to identify the optimum preparation conditions of CuMnOx catalyst with respect to the performance of catalyst for CO oxidation. Copyright © 2017 BCREC Group. All rights reserved Received: 9th January 2017; Revised: 24th May 2017; Accepted: 25th May 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Dey, S., Dhal, G.C., Mohan, D., Prasad, R. (2017). Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3): 431-451 (doi:10.9767/bcrec.12.3.900.437-451

Two Major Archaeal Pseudomurein Endoisopeptidases: PeiW and PeiP

PeiW (UniProtKB Q7LYX0) and PeiP (UniProtKB Q77WJ4) are the two major pseudomurein endoisopeptidases (Pei) that are known to cleave pseudomurein cell-wall sacculi of the members of the methanogenic orders Methanobacteriales and Methanopyrales. Both enzymes, originating from prophages specific for some methanogenic archaeal species, hydrolyze the ϵ(Ala)-Lys bond of the peptide linker between adjacent pseudomurein layers. Because lysozyme is not able to cleave the pseudomurein cell wall, the enzymes are used in protoplast preparation and in DNA isolation from pseudomurein cell-wall-containing methanogens. Moreover, PeiW increases the probe permeability ratio and enables fluorescence in situ hybridization (FISH) and catalyzed reporter deposition (CARD-) FISH experiments to be performed on these methanogens