bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization of Boric Acid through Reactive Dissolution of Oxalic Acid Crystals in Aqueous Borax Solution
Authors: Zarenehad B. , Garside J. 
Published: August 2010

AbstractIn the reaction between solid oxalic acid and aqueous borax solution, product boric acid precipitates in the solution phase after complete dissolution of oxalic acid crystals. This makes it possible to measure the dissolution and precipitation kinetics independently. The oxalic acid dissolution process was found to be diffusion controlled. Nucleation rates of product boric acid were influenced by heterogeneous primary nucleation and secondary nucleation, while growth rates were affected by both the bulk diffusion and surface integration processes. Dissolution of oxalic acid ctystals was described by a surface reaction model, and overall nucleation and growth rates were correlated in terms of the influencing process variables. Simulation analysis was carried out by linking the two processes of dissolution and precipitation in series. The trends of the predicted supersaturation profiles, number concentration, magma density and mean size of the product crystals are in good agreement with measured values.
Blown Film Processing Characteristics of Metallocene and Conventional Polyethylenes
Authors: Johnston A.D. , Mcnally G.M. , Clarke A.H. 
Published: August 2010

AbstractPart A ‐ A range of polyethylene films were prepared from metallocene linear low density polyethylene (mPE) and linear low density polyethylene (LLDPE). The films were manufactured using blow up ratios (BUR) of 1.3 ‐ 2.5, haul‐off rates, and screw speeds to give a uniform thickness of 50 microns. Tensile analysis of the samples showed that modulus and elongation were related to both comonomer type and polymer density. The mPE resins possessed considerable improvement in mechanical performance compared to conventional PEs. Differential Scanning Calorimetry (DSC) analysis demonstrated that the degree of crystallinity was more dependent on extrusion processing conditions and polymer density than comonomer type.Part B ‐ Films were prepared from a range of mPE resins of various comonomer types (hexene and octene). The films were manufactured at a constant blow up ratio of 1.6 by maintaining constant haul off speeds and screw speeds to give a uniform thickness of 50 microns. To effect the change in frostline height, the rate of cooling was changed. Tensile analysis of the samples showed that modulus and tensile stress were related to both comonomer type and polymer density and that frostline height variation had an effect on the final film properties. Change in the percentage crystallinity of each of the samples at the different cooling rates also demonstrated how the processing factors of the blown film line can influence film properties.
The Effect of Compatibilisation for Blends of Nylon 6 or Polybutylene Terephthalate (PBT) with Metallocene Linear Low‐Density Polyethylenes
Authors: Gribben F. , Mcnally G.M. , Clarke A.H. , Murphy W.R. , Mcnally T. 
Published: August 2010

AbstractPolymer blends of polyamides and polyethylenes are immiscible and highly incompatible. These blends are characterised by high interfacial tension, a two‐phase morphology and poor physical characteristics due to reduced interaction across the phase boundaries. PBT like many other polymers is a brittle material with a high modulus value and is not suitable for certain applications. Blending and compatibilising with an incompatible polyethylene phase may improve these properties. The compatibilising agent, maleic anhydride‐grafted‐LLDPE, is physically miscible with the polyethylene phase and has a chemical functionality with the polyamide phase and the carboxylic and hydroxyl end groups of the PBT phase. The use of a new generation mLLDPE (ENGAGETM by Dupont) was also studied to investigate its suitability as a modifier for the polyamide and polyester grades. The influence of the percentage composition of the mLLDPE and the effect of the addition of the compatibiliser were both investigated for their effect on the mechanical properties. They were both shown to significantly improve the modulus and elongation with only a slight reduction in the impact properties of the final product.
Effect of Phthalocyanine Blue Pigment on Mechanical and Thermal Properties of polypropylene copolymers
Authors: Major I.F.M. , Mcnally G.M. , Clarke A. , Ross H. 
Published: August 2010

AbstractSamples of two commercial polypropylene copolymers, one a random copolymer and the other a block copolymer, containing 0–8wt.% phthalocyanine blue pigment were injection moulded using mould temperatures of 40d̀C to 80d̀C. Dynamic Mechanical Thermal Analysis (DMTA) and Differential Scanning Calorimeter (DSC) analysis showed the presence of different crystalline phases in each polymer, the amount of each phase changing with increasing pigment loading. With these changes in the crystalline phases there was a progressive increase in tensile modulus, storage modulus (E') and glass transition temperature (Tg) for both copolymers. Impact performance of both pigmented copolymers decreased with an increase in pigment loading and mould temperature, with the most dramatic result shown for the random copolymer. These impact results were mirrored by the fall in loss modulii of both copolymers with increasing pigment loading.
Exfoliation Kinetics of a Phyllosilicate‐Organoclay Structure in a Polymer Matrix during Melt‐Extrusion Process
Authors: Lew C. Y. , Murphy W. R. , Mcnally G. M. 
Published: August 2010

AbstractNanostructured polymer‐composite materials were prepared by melt‐exfoliating the smectite structure of a synthetic tetrasilisic fluoromica in a nylon‐12 matrix, by means of a melt‐extrusion process using a single‐screw extruder. The structure and morphology of these materials were evaluated using the X‐ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. Uniform dispersion of exfoliated slicate layers were observed throughout the polymer matrix. Rheological studies using a dual capillary rheometer showed that the melt viscosity of the nanocomposites was dependent on the degree of clay exfoliation, and in addition the orientation of the layered‐silicates in the polymer matrix. The exfoliation and orientation of layeredsilicates were in turn dependent on the processing conditions adopted. Typically a lower processing shear would improve the intercalation of the layered‐silicates while increasing shear enhanced their exfoliation. Improved exfoliation was shown to decrease the polymer melt viscosity, which may be attributed to the plasticising effect of the clay platelets.
Diffusion of Methanol, Ethanol and Toluene in Nylon 12 and Poly(butyleneterephthalate)
Authors: Mccourt M. P. , Mcnally G. M. , Ruddy A. C. , Murphy W. R. 
Published: August 2010

AbstractThis work investigates the diffusion of methanol, ethanol and toluene in polybutyleneterephthalate (PBT) and nylon 12 over a range of temperatures from 8d̀C to 60d̀C. The results show that substantial solvent uptake was noted for nylon in methanol and ethanol. Solvent uptake in PBT occurred only at the higher temperatures in toluene. Dynamic mechanical thermal analysis (DMTA) also showed progressive decrease in the glass transition temperature (Tg) and storage modulus (E') with increase in solvent uptake.
Momentum Balance for Two‐Phase Horizontal Pipe Flow Part 1: Friction Factors
Authors: Spedding P. L. , Cole J. S. , Donnelly G. F. 
Published: August 2010

AbstractEstimations of gas wall, liquid wall and interfacial friction factors for two‐phase horizontal co‐current pipe flow are discussed critically after being checked against reliable data obtained under a wide range of conditions. The use of equivalent diameters and the Blasius relation were shown to be valid for estimation of the gas wall friction. Prediction of liquid wall and interfacial friction factors proved to be more difficult but estimation improved if consideration was given to the effects of liquid holdup and interfacial liquid shape.
Production Variance in Purified Carboxymethyl Cellulose (CMC) Manufacture
Authors: Stigsson Veronica , Wilson David I. , Germgärrd Ulf 
Published: August 2010

AbstractThis study investigates the variance in industrial production of carboxymethyl cellulose (CMC). Initially it was thought that the product exhibited excessive quality variations. However careful viscosity and molecular weight distribution measurements on both the raw material and the final product, supplemented with online quality measurements, showed that the product variations were less severe than originally thought. The most probable reason for this unfounded quality concern is due to imperfect routine measurements coupled with a limited reporting of the subsequent offline laboratory analysis. The situation where the routine quality analysis plays as much a role in the uncertainty as the production itself is believed to be of general relevance for the chemical processing industries.
A New Approach to Monitoring the Movement of Particulate Material in Rotating Drums
Authors: Davies C. E. , Williams A. , Tallon S. J. , Fenton K. , Brown N. 
Published: August 2010

AbstractRotating drums are widely used for a variety of particle processing operations including mixing, calcining, and granulation. The mode of motion of the particles can be characterized as one of seven regimes and three of these, “slumping”, “rolling”and “cascading” are relevant to industrial practice. This paper describes apparatus in which a rotating cylinder is mounted on a pivoted framework acting on a load cell. Changes in the position of the centre of mass of the material in the drum cause changes in the moment measured by the load cell, and experimental results are presented showing that the variance of the load cell signal can be used to track the transition from slumping to rolling. A simple model that can facilitate the interpretation of the load cell output in terms of gross movement of material in the drum is outlined, and load cell response in the slumping regime, is discussed with reference to video footage of particle motion.
Challenges in Multiscale Modelling and its Application to Granulation Systems
Authors: Ingram G. D. , Cameron I.T. 
Published: August 2010

AbstractSince the mid 1990s there has been on increasing recognition of chemical engineering's multiscale nature. Multiscale modelling attempts to create flexible and efficient models by linking two or more partial models that describe phenomena at different characteristic length and time scales. In the first part of this paper, we briefly review multiscale modelling in chemical engineering. Three key tasks used in multiscale modelling are identified, and the current practices and unresolved issues in each are discussed. The second part of the paper examines the modelling of a wet granulation circuit from a multiscale perspective. A ‘scale map’ for drum granulation is proposed to assist in visualising the multiscale nature of the system. The three multiscale modelling tasks are considered in turn and some suggestions for modelling are proposed. Through this paper we are seeking to promote discussion on multiscale modelling and to receive feedback on its application to granulation.
Gas/Liquid Mass Transfer in Hot Sparged Systems
Authors: Zhu Y. , Wu J. 
Published: August 2010

AbstractUnderstanding the effect of temperature on the volumetric mass transfer rate is of vital importance for the design of chemical reactors operated at elevated temperatures. The present study is motivated by a poor understanding of this effect due to previous limited investigations. Such an effect has been studied at the CSIRO Energy & Thermofluids Engineering Laboratory in a mechanically agitated air‐water mixing tank with operating temperatures in the range of 20‐80d̀C at atmospheric pressure. The oxygen concentration of the liquid is measured by a dissolved oxygen probe. The volumetric mass transfer rate is estimated using a dynamic method. It has been found that the saturated oxygen concentration of the liquid does not change significantly with the gas sparging rate and impeller speed. The change of temperature affects the saturated oxygen concentration significantly. The volumetric mass transfer rate increases with the increase of liquid temperature in the range of 18‐60d̀C. Beyond 60d̀C, the transfer rate decreases. Such a decrease is mainly due to the dramatic drop in the gas void fraction.
Iron Ore Characterisation during High Temperature Thermal Processing
Authors: McCann G. , Strezov V. , Lucas J. A. , Evans T. , Strezov L. 
Published: August 2010

AbstractIronmaking essentially involves different ways of combining iron ores and energy sources to produce metallic iron. The thermal properties of the iron ores determine the amount of energy required for processing. Investigating and understanding these thermal properties is thus extremely important with respect to controlling the ironmaking processes.Using experimental and mathematical techniques, six iron ores from different origins were thermally characterised in this study. Chemical and structural changes in the iron ore during heating were investigated using SEM, EDS, and XRD analysis. Throughout the process, a number of transformations and reactions were apparent, and these have been quantified for each ore.Goethite was found to decompose between 250‐350 d̀C. This endothermic reaction was found to be the most important stage with the energy requirement to heat iron ore samples dependent upon the amount of goethite in the iron ore. The endothermic kaolinite decomposition occurred at 600 d̀C while the exothermic partial reduction of hematite to magnetite occurred at 850 d̀C. Differences between the raw and sintered iron ores were investigated.
A Tutorial on Model Predictive Control: Using a Linear Velocity‐Form Model
Authors: Wang Liuping 
Published: August 2010

AbstractModel Predictive Control (MPC) has a long history in the field of control engineering. It is one of the few areas that has received on‐going interest from researchers in both industry and universities. It has been recognised that there are three major branches of MPC algorithms consisting of step‐response model based design: Dynamic Matrix Control (DMC); transfer function model based design: Generdised Predictive Control (GPC); and a general state space model based design. The DMC and GPC algorithms can also be caste in the state space framework. Along the genera lines of state space methods, there are two mainstreunts: one solves for the optinzal control signal while the other solves for the increment of the optimal control signal. The latter can be implemented in a velocity form analogous to the implementation of a PID controller on an industrial plant. Motivated by this advantage. and that integral action is naturally embedded in the algorithm, this tutorial paper focuses on an introduction to Model Predictive Control based on the state space approach using a linear velocity‐form model.
Use of Sorption Isotherms for the Estimation of Shelf Life of Two Zimbabwean Flours
Authors: Ikhu‐Omoregbe D. I. O. , Chen X. D. 
Published: August 2010

AbstractThe water sorption characteristics of two Zimbabwean flours, i.e. maize‐meal and millet, were obtained using the gravimetric method at temperatures of 20, 30 and 4Od̀C. The GAB, BET and the modified BET models were found to describe the data reasonably well. The heat of sorption, which varied from 1.915 kJ.mol−1 at 20% moisture content to 30.5 kJ.mol−1 at 1% moisture content dry‐basis was calculated for the maize meal. Similar values for the millet were found to vary from 1.87 kJ.mol−1 at 20% moisture content to 18.3 kJ.mol−1 at 1% moisture content. The shelf lives for both materials were estimated from the sorption data, and recommendations on packaging and storage conditions are suggested.
Stochastic Model Reduction by Maximizing Independence
Authors: Zhang Hui , Sun You‐Xian 
Published: August 2010

AbstractBy analysing information descriptions in state space models of linear stochastic systems, this paper proposes two model reduction methods via principles of maximizing independence and conditional independence among the reduced state vector, respectively. These methods are based on state aggregation. The independence and conditional independence are measured by the Kullback‐Leibler information distance. It is demonstrated that the maximum conditional independence method is not only applicable to stable systems, but also applicable to unstable systems. Simulation results illustrate the efficiency of the present methods.
Dynamic Simulation and Advanced Control of a Heat Integrated Plant
Authors: Tellez R. , Svrcek W. Y. , Young B. R. 
Published: August 2010

AbstractHeat integrated plants involving exothermic chemical reactions show a degree of positive feedback and instability when trying to control the outlet temperatures of process‐to‐process, feed‐effluent heat exchangers. This is the case for the hydrodealkylation (HDA) of toluene process. In this study a 2 × 2 Model Predictive Control (MPC) scheme was implemented for the first time on a dynamic simulation of the HDA Plant. Comparison of its performance against the classical Ziegler‐Nichols and IMC tuning techniques for PI control was also carried out. The performance tests implemented suggest that PI control and MPC implemented over PI control are good choices to control this heat‐integrated plant.
Accurate Location Method of Drilling Hole Activities on Oil Pipelines based on Wavelet Packet
Authors: Wang Qiang , Zhou Ze‐Kui , Zhang Guang‐Xin , Gu Xiao‐Hong 
Published: August 2010

AbstractA method of detecting drilling hole activity and locating accurate sources in buried oil pipelines was developed, based on vibration signal propagation and wavelet packet transform (WPT). Experiments were performed to locate man‐made damaging sources. Complicated disturbances in the field cause large location errors with the direct cross correlation method. Therefore, WPT is used to decompose the signal into a series of time domain signals, each of which covers specific frequency band information. Packets containing large amounts of energy are focused on, and selected as, feature packets to reconstruct the signal, then cross‐correlation analysis is applied. Finally, by comparing the correlation coefficients of the reconstructed signal, the time point corresponding with maximum correlation coefficient is selected as delay time, which determines the location of the drilling site. Results show that the proposed method improves location precision in detection.
On‐line Fault Detection and Diagnosis in Industrial Processes Using Hidden Markov Model
Authors: Zhou Sha‐Yuan , Wang Shu‐Qing 
Published: August 2010

AbstractFor many on‐line fault diagnosis schemes based on process data, a moving time window is an indispensable technique to track dynamic data. In this paper, a novel approach combining variable moving window and hidden Markov model (HMM) for on‐line identification of abnormal operating conditions is proposed. The main feature of this method is that the window length can be changed with time. Before fault diagnosis, some process measurements are used for fault alarm. As a tool for feature extraction, principal component analysis (PCA) is employed in order to reduce the large number of correlated variables. The effectiveness of the approach is illustrated by case studies from the Tennessee Eastman process.
An Experimental Study on Flue Gas Desulphurisation by Fluidised Absorption
Authors: Zhong Z.P. , Lan J.X. , Jin B.S. , Chen S.B. , Gen H. 
Published: August 2010

AbstractThis paper presents a novel wet flue‐gas desulphurisation (FGD) process using fluidised absorption with lime/limestone. A series of experiments were conducted using a hot‐state test facility of a capacity of 2000 Nm3/h flue gas in order to evaluate this FGD technology. The results indicate that the desulphurisation efficiency increased with slurry concentration, immersed depth of the bubbling pipe under the slurry, and the velocity of agitation. A high desulphurisation efficiency (95%) can be achieved under conditions of pH 5 to 8. an immersed depth of bubbling pipe under the slurry of 160 to 200 mm, a jet rate of 10 to 25 m/s, a slurry concentration of less than 7%, a temperature of 55 to 60d̀C, and the application of agitation
The Oxidation Kinetics of Mercury in Hg/O/H/Cl System
Authors: Qiao Y. , Xu M.H. 
Published: August 2010

AbstractThe potential for regulation of mercury emission from coal‐fired boilers is a concern for the electric utility industry. Field data show a wide variation in the fraction of mercury that is emitted as a vapor versus that retained in the solid products. The reason for this variation is not well understood. Near the end of the flue gas path, mercury exists as a combination of elemental vapor and HgCl2 vapor. The data show that HCl2 is more likely to be removed form the flue gas. The need to describe accurately mercury reaction products and their concentration‐time correlation prompted investigation of mercury chemical kinetic mechanisms and their application to real combustion systems. This paper uses chemical equilibrium analysis to study the speciation of mercury in flue gases during coal combustion and gasification. The paper presents a simple kinetic model of mercury oxidation in the Hg/O/H/Cl system. The results porn the model calculation are in reasonable agreement with the Mamani‐Paco and Heleble [1] experimental data
Sensitivity to Hydrogen Peroxide of Growth and Hyaluronic Acid Production by Streptococcus zooepidemicus ATCC 39920
Authors: Mashitah M.D. , Masitah H. , Ramachandran K.B. 
Published: August 2010

AbstractThe sensitivity to hydrogen peroxide (H2O2) of growth and hyaluronic acid (HA) production by Streptococcus zooepidemicus ATCC 39920 was studied under various conditions. In sheep blood agar‐plates, no detectable zone was observed even when the concentration of H2O2 was increased to 0.15 mM. With brain heart infusion‐agar and chemically defined medium‐agar plates, a profound zone was detected at 0.015 mM concentration of H2O2. To determine the minimal inhibitory concentration (MIC) of the strain in culture broth, various concentrations of H2O2 (0‐200 mM) were maintained in the medium prior to fermentation. The result showed that for higher concentrations of H2O2 in the medium, the greater was the inhibition. Streptococcus is catalase‐negative and known to produce H2O2 which may affect growth, HA production and glucose utilization. In order to determine at which growth phase H2O2 had the maximum inhibitory activity, a batch fermentation of S. zooepidemicus was conducted in shake flask culture. It was found that H2O2 production took place during the growth phase, and HA production started after the growth had reach late exponential phase when H2O2 in the culture media was depleted. This indicates that H2O2 produced by the cells did not affect cell growth but influenced HA production.
Initial Screening of Fermentation Variables for the Production of Cyclomaltodextrin Glucanotransferase (CGTase) from Local Isolated Bacillus stearothermophillus HR1
Authors: Wong T.E. , Illias R.M. , Rahman R.A. , Ismail A.F. , Salleh M. M. , Hassan O. , Kamaruddin K. 
Published: August 2010

AbstractThis paper presents results on the effect of fermentation variables on CGTase production from Bacillus stearothermophilus HR1. Initial screening of temperature, pH and agitation speed was determined using a 2‐level full factorial design. In this study, we have improved the production of cyclodextrin glucanotransferase (CGTase) from Bacillus stearothermophilus HR1 in flasks using the experimental design approach. The regression model generated for the correlation of CGTase with the variables was 99.97% accurate. Results of the screening process indicated that pH and agitation speed were of greater significance compared to temperature. Results suggested that only two variables, namely pH and agitation speed, should be considered in future optimization studies. Temperature was least significant and it was set at 55d̀C where CGTase production of 10.41 U/ml was slightly higher compared to temperatures of 37d̀C, 45d̀C, 50d̀C and 60d̀C.