bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluid Flow through 90 Degree Bends
Authors: Spedding P.L. , Benard E. , Mcnally G.M.
Published: August 2010

Pressure drop measurement and prediction in curved pipes and elbow bends is reviewed for both laminar and turbulent single‐phase fluid flow. For curved pipe under laminar flow, the pressure loss can be predicted both theoretically and using empirical relations. The transitional Reynolds number can be predicted from an empirical relation. Turbulent flow in curved pipes can only be theoretically predicted for large bends but there are a large number of empirical relations that have proved to be accurate. Elbow bends have proven to be difficult to both measure and represent the pressure loss. Methods of overcoming such problems are outlined. There was no reliable method of theoretically predicting pressure drop in elbow bends. Experimental measurements showed considerable scatter unless care was taken to eliminate extraneous effects. Reliable data are highlighted and an empirical method is proposed for calculation of pressure drop in elbow bends.
Momentum Balance for Two‐Phase Horizontal Pipe Flow Part 2: Testing of Models
Authors: Spedding P. L. , Cole J. S. , Donnelly G. F.
Published: August 2010

Momentum balance models were tested against reliable data for both holdup and pressure drop. The best prediction performance was achieved using a model that considered the actual shape of the liquid phase in the pipe. In such circumstances the momentum balance calculation tended to under predict both the holdup and pressure drop for some of the annular and stratified regimes. Suggestions are made for improvements in the momentum balance approach.
Stabilization of the Dynamic Behavior of a UNIPOL Process for Polyethylene Production
Authors: Ghasem Nayef Mohamed , Hussain Mohamed Azlan
Published: August 2010

Polyolefins have become one of the most important plastics worldwide due to continuous improvements in catalysts and processes. Gas‐phase polymerization of olefins is one of the most important polymerization processes. Compared to other processes such as slurry and solution polymerization, gas‐phase processes have many distinct advantages, e.g. reduced capital and operating costs. Moreover, gas‐phase polymerization offers a large variety of products, which could not be produced by other processes. However, sheeting and agglomeration of polymer particles are two serious problems, which can occur in modern gas‐phase polymerization processes. Overheating of particles may occur due to very high reaction rates. The temperature of a particle can then rise above the softening temperature. In this work, recent theories of bifurcation and chaos are used to analyze the dynamic behavior of the UNIPOL process for the gas‐phase production of polyethylene using a Ziegler‐Natta catalyst. The dynamic behavior covers a wide range of the design and operating parameters domain for this industrially important unit. A conventional proportional‐integral‐derivative (PID) controller was implemented to stabilize the desired operating point on the unstable steady‐state branch to a certain range of catalyst injection rate. By contrast, it was found that the controlled process can go through a period doubling sequence leading to chaotic strange attractors. The practical implications of this analysis can be very serious, since chaos is shown to exist close to the desired operating point where high polyethylene production rates can be achieved.
The Optimisation of Drying Schedules for Pinus radiata Sapwood Boards
Authors: Langrish T.A.G. , Nijdam J. J. , Keey R. B.
Published: August 2010

Optimal drying schedules have been predicted for the drying of Pinus radiata sapwood from an initial moisture content of 140% over a drying time of twenty‐four hours for 50mm‐thick boards. Initially, a single pair of dry and wet‐bulb temperatures (108d̀C. 60d̀C) over the full time period is estimated to keep the total tangential strain under 50% of the predicted limiting failure value. However, after twelve hours drying, more severe conditions may be used, with the final moisture content predicted to be reduced from 8.2% for a constant set of conditions throughout the schedule (108d̀C, 60d̀C) to 2.4% when the dry‐bulb temperature is raised from 108d̀C to 122d̀C after twelve hours. It is also possible to use a linearly increasing dry‐bulb temperature after twelve hours, rising from 108d̀C to 155d̀C at the end of drying with a predicted final moisture content of 0.2%. However, to reduce the moisture content to only 10%, there is little difference between the ramped and two‐step schedules, both yielding a total drying time of eighteen hours. The two‐step schedule would be the easier to in practice.
Progress in the Modelling of Air Flow Patterns in Softwood Timber Kilns
Authors: Langrish T.A.G. , Keey R. B.
Published: August 2010

Progress in modelling air flow patterns in timber kilns using computational fluid dynamics (CFD) is reviewed in this work. These simulations are intended to predict the distribution of the flow in the fillet spaces between boards in a hydraulic model of a timber kiln. Here, the flow regime between the boards is transitional between laminar and turbulent flow, with Reynolds numbers of the order of 5000. Running the simulation as a transient calculation has shown few problems with convergence issues, reaching a mass residual of 0.2% of the total inflow after 40 to 100 iterations per time step for time steps of 0.01 s. Grid sensitivity studies have shown that non‐uniform grids are necessary because of the sudden changes in flow cross section, and the flow simulations are insensitive to grid refinement for non‐uniform grids with more than 300,000 cells. The best agreement between the experimentally‐measured flow distributions between fillet spaces and those predicted by the simulation have been achieved for (effective) bulk viscosities between the laminar viscosity for water and ten times that value. This change in viscosity is not very large (less than an order of magnitude), given that effective turbulent viscosities are typically several orders of magnitude greater than laminar ones. This result is consistent with the transitional flows here. The effect of weights above the stack can reduce the degree of non‐uniformity in air velocities through the stack, especially when thick weights are used, because the stack may then be separated from the eddy at the top of the plenum chamber.
The Deposition of Calcium Oxalate and Amorphous Silica Scale under Dynamic Conditions which Simulate sugar mill Evaporators
Authors: Yu H. , Sheikholeslami R. , Doherty W.O.S.
Published: August 2010

Composite fouling of calcium oxalate monohydrate (COM) and amorphous silica (SiO2) in sugar mill evaporators poses a major processing problem. The significance of COM‐SiO2 interactions during composite scale formation has been recognized previously and their effects on the fouling behaviour of both species have been demonstrated in batch tests. This work investigates the mechanisms of composite fouling of COM and SiO2 in a dynamic system under subcooled flow‐boiling and continuous evaporation. The experimental approach used in this study is novel. It simulates the operation cycle in the latter effects of sugar mill evaporators within one experimental run whilst maintaining a relatively simple process. The composite fouling behaviour of COM and SiO2 has been tested in aqueous solutions with a range of COM/SiO2 supersaturation ratios to determine the critical feed composition at which the maximum degree of composite fouling occurred. The synergistic effect of COM on composite fouling occurred at an intermediate concentration of COM (50 ppm) whereas antagonism was obtained at either low or high COM concentration (20 and 100 ppm). This may be due to changes in the magnitude of the interfacial energy barrier between the surface of the particles and the wall, and to the differences in the physical properties of the fouling species such as particle size.
Using a “Campus as a Classroom Concept” to Highlight Sustainability Practice to Engineers and Scientists
Authors: Evans G. , Scaife P. , Maddox B. , Galvin K.
Published: August 2010

Chemical engineering at the University of Newcastle has introduced a “Systems Thinking” approach in response to the changing needs of today's young engineers, particularly in relation to sustainable development and interaction with the wider community. The basic concepts are reinforced to the students in the form of case studies. The activities cover a broad range of traditional chemical engineering principles, including fluid mechanics, heat and mass transfer, process flowsheeting, and design. The case studies have the additional dimensions of life cycle modelling, environmental impact assessment, and direct interaction with the broader community. In this paper, two examples, involving Building Design and On‐Site Water Management, are presented, including a brief description, desired learning outcomes, results and general observations. Generally, it was found that the case studies provided an excellent framework for establishing a systems approach to arriving at solutions, and acted as a focus for quantitative analysis using the various tools taught during the course. Most importantly, the material presented assisted students to understand the practices which contribute to the transition to a sustainable society.
Experimental Results and Models for Solid/Liquid Fluidized Beds Involving Newtonian and Non‐Newtonian Liquids
Authors: Aghajani M. , Müller‐Steinhagen H. , Jamialahmadi M.
Published: August 2010

Fluidization technology relies almost solely on fluid/particle interaction wherein the liquid phase may exhibit Newtonian or non‐Newtonian behavior. The steady motion of particles and the velocity‐voidage relationship are the most important design parameters for fluidization, providing the basis for the prediction of heat and mass transfer coefficients and information on hydrodynamic conditions. A summary of the literature on particle settling velocity, minimum fluidization velocity and velocity voidage relationship is supplemented by new experimental results, which extend the range of investigated solid and liquid phase physical properties. Correlations for particle settling velocity and velocity‐voidage relationship are developed and verified against experimental data.
Hydrogen Economy Options for Australia
Authors: Mclellan B. , Diniz Costa J. C. Da , Dicks A.L. , Rudolph V. , Pagan R.J. , Sheng C. , Wall T.F.
Published: August 2010

Global concerns over the effects of current carbon dioxide (CO2) emissions have lead to extensive research on the use of hydrogen as a potential energy carrier for a lower emissions society. Hydrogen can be produced from both fossil and renewable energy sources. The hydrogen economy, in which hydrogen will be a carrier of energy from renewable sources, is a long‐term development and any increasing demand for hydrogen will probably be covered initially from fossil sources. Technologies for hydrogen generation from renewable energies are being explored, whereas technologies for hydrogen production from fossil fuels have to a certain extent reached maturity. This paper addresses the major hydrogen generation processes and utilisation technology (fuel cells) currently available for the move from a fossil fuelsbased economy to a hydrogen economy. In particular, it illustrates the applicability of different hydrogen sources using Australia as an example.
Research and Development Trends in Biodiesel
Authors: Rudolph V. , He Y.
Published: August 2010

Biodiesel, a derivative from plant oils or animal fats, has gained widespread acceptance in recent years as a sustainable alternative fuel to petroleum diesel due to its environmental benefits and renewability. Although there are several different ways in which biodiesel can be used or formulated as a fuel such as direct blending, microemulsions and thermal cracking, the most widespread remains the alkyl esters of fatty acids obtained through transesterification of the oils or fats. In transesterification, triglycerides which are the main chemical in oils or fats are converted into esters through reaction with simple alcohols. The physical and chemical properties of the esters thus obtained are very similar to those of the petroleum diesel.

This paper reviews the current technologies available for the transesterifications of vegetable oils and animal fats and identifies that the biggest factor deterring a greater market uptake of biodiesel is its cost. It concludes that, in addition to government policy framework, e.g. to reduce the pump price of biodiesel through fuel tax exemption, further technological development presents significant scope for improvement. At present, there are no suitable and developed transesterification technologies that can handle cheap, low‐quality feedstocks including waste animal fats and spent cooking oils. These feedstocks contain high percentages of water and free fatty acids which are extremely detrimental to the yield and reaction rates of the transesterification processes. This paper also suggests some future research and development directions and requirements for more competitive biodiesel production.
An Assessment of Tarong Bottom Ash for Use on Agricultural Soils
Authors: Wearing C. , Birch C.J. , Nairn J.D.
Published: August 2010

Coal combustion by‐products (CCBs), including fly ash and bottom ash, present a waste disposal problem in Australia due to a continuing demand for coal‐fired power. Pozzolanic Enterprises handle ash produced by the Tarong Energy coalfired power station in South West Queensland, which produces approximately 1,200,000 tonnes per annum of CCB's. This comprises roughly 1,100,000 tonnes of fly ash arid 100,000 tonnes of furnace bottom ash. The volume and unique properties of the Tarong bottom ash present a significant opportunity for agronomic use. Of particular interest is the ability of Tarong bottom ash to markedly improve the water‐holding capacity of soils. Given that Australia's rural environment is currently enduring a ‘one‐in‐one‐hundred‐year’ drought a study of the ability of Tarong bottom ash to improve water holding capacity is timely. This paper details physical and chemical properties relevant to agronomic use, and water‐holding capacity of ash/hoil blends, along with experiences in its field use in crop production.
The Validation of a Simple Gaussian Dispersion Model for Determining Odour Emission Rates from Area Sources
Authors: Galvin G. , Lowe S. , Smith R.
Published: August 2010

The accuracy of dispersion models is a widely debated topic. The goal of this research was to assess If the odour emission rates (OER) predicted using a simple Gaussian model were comparable to the more intensive and expensive wind tunnel‐based odour measurement technique. A Gaussian dispersion model (STINK) was used to determine odour emission rates from piggery ponds. These values were then compared to those measured simultaneoirsly on the pond sugaces using a wind tunnel, and analysed using dynamic olfactometry. Results of linear regressions showed a moderate relationship for two of the three seasons studied, and a very good relationship for the other season studied. Overall, the model showed a good correlation between calculated downwind, and calculated on‐pond, odour emission rates. The use of the STINK model shows promise as an alternative to the inore labour‐intensive direct emission rate measurement technique.
Methanol as Anti‐solvent for Recycling of Caustic Soda Solution Used in Aluminum products manufacturing
Authors: Fukui K. , Maeda K. , Yanagisawa T. , Honda K. , Yoshida M.
Published: August 2010

The recycling of caustic soda solution in aluminum processing is proposed in order to decrease the energy consumption and environmental impact. Methanol as an anti‐solvent in the caustic soda solution was found to be the most effective solvent for reducing gibbsite solubility. The gibbsite solubility in caustic soda was significantly reduced when methanol was added by more than 40 wt%. It was found that the gibbsite solubility with 55 w t% methanol was about a half of that without methanol. Methanol has low latent heat, and can be economically separated from the caustic soda solution. This recycling leads to an increase in the dissolution rate of alumina and/or aluminum, at atmospheric pressure, with a more concentrated caustic soda solution (up to 500 g/L NaOH). A more concentrated caustic soda solution can be recycled more economically, for example, that used in the die recovery process in aluminum forming plants. Optimization by the controlled addition or mixing of methanol in the caustic solution easily controls the growth rate and nucleation rate of gibbsite crystals in the crystallizer. Synergy of these advantages of the present recycling method may contribute to more cost effective operations, and minimization of environmental impacts from the disposal of spent caustic soda solution.
Prediction of Hydrogen Content in Coal using Back Propagation Neural Network
Authors: Ju L. C. , Tadé M. O. , Zhu J. N. , Yao H. M.
Published: August 2010

This paper introduces the concept of sample study risk in neural network (NN), and studies the prediction of hydrogen content in coal using Back Propagation Neural Networks (BP NN). Targeting the problem of training convergence quality impaired by the interfering information of some samples in BP NN, the validity of the concept of sample study in NN, and the feasibility of analyzing chemical elements in coal using NN are discussed.
Application of a Robust Interval Observer to an Anaerobic Digestion Process
Authors: Alcaraz‐González V. , Steyer J. P. , Harmand J. , Rapaport A. , González‐Alvarez V. , Pelayo‐Ortiz C.
Published: August 2010

A new robust state estimation scheme is proposed for chemical and biochemical processes. This scheme is a nonlinear interval observer which is robust in the face of uncertainties of the inputs, load disturbances and the nonlinearity of the system, while maintaining excellent stability conditions. We show that this observer yields satisfactory estimates of the unmeasured states within a guaranteed interval determined by the available measurements and some reasonable hypotheses about the observer inputs. For demonstrating the effectiveness and applicability of the proposed estimation scheme, we apply it in an actual anaerobic digestion pilot plant for wastewater treatment in the presence of uncertainties including measuring errors, sensor failures, time varying inputs and unmeasured disturbances. On‐line implementation results reveal that the proposed robust nonlinear interval observer is a practical and encouraging approach to the robust state estimation in uncertain nonlinear processes.
A Novel Method for the Control of Plants with actuator Saturation Nonlinearities
Authors: Gu Dan‐Ying , Cai Yun‐Ze , Zhang Wei‐Dong
Published: August 2010

The objective of this paper is to develop a simple and practical anti‐windup controller for systems with saturation non‐linearity. Most present methods are based on the idea that when the controller output differs from the plant input, then corrective feedback is employed to reduce the discrepancy. Alternatively, some recent design methods propose that the saturation can be avoided by directly making the controller output in a permissible range. This paper will give such a scheme. It is essentially a modification, or compensation, to existing controllers that can be designed in various ways for linear systems. The scheme is realized by adding a filter to the controller, and is tuned only for a few parameters in order to cope with the saturation. It is simple and efficient in practical applications. Illustrative examples are provided to show the advantage of the proposed method.
Approximate Decoupling of Multivariable Control Systems: A Time‐domain Approach
Authors: Mao Wei‐Jie , Liu Shao
Published: August 2010

A new approximate decoupling method for linear time‐invariant systems based on the concept of energetic diagonal dominance is proposed in this paper. It is a time‐domain approach and the design procedure is simpler than that of frequency‐domain approach. The conditions for the energetic decoupling with simultaneous stabilizability are established in terms of linear matrix inequalities (LMIs). It is very convenient to solve this problem using the powerful LMI toolbox. The results are derived first for proper systems with nonsingular D, and then extended to strictly proper systems. Illustrative examples demonstrate that this method has satisfactory decoupling performance.
A New Method for the Static Output Feedback Stabilization
Authors: Xiang Ji , Su Hong Ye , Chu Jian
Published: August 2010

The problem of the static output feedback stabilization is the solvability of the two invert‐coupled matrix inequalities. This is non‐linear optimal problem and cannot be solved directly. In this paper, the relation of the two coupled matrix inequalities is studied and a sufficient condition of the solvability for the stabilization problem is proposed on a structural Lyapunov matrix. The corresponding algorithm is presented, which is non‐iterative and simply solved by linear matrix inequality (LMI) tools. Examples are given to show the simplicity and effectiveness of the proposed method.
A New Particle Predictor for Fault Prediction of Nonlinear Time‐varying Systems
Authors: Chen M.Z. , Zhou D.H. , Liu G.P.
Published: August 2010

Fault prediction (FP) is a new research area in fault detection and diagnosis. It has both safety and economic benefits in industrial systems by preventing future serious process faults and improving process maintenance schedules. Fault prediction differs from fault detection because it deals with future faults, whereas the latter considers faults that occurred in the past. As the future fault is uncertain, a probability to describe it may be needed, however calculating the fault probability remains an open problem. This paper proposes a new particle predictor‐based method by which a solution to fault prediction is derived for nonlinear time‐varying systems. Simulation results illustrate the effectiveness of the proposed approach.
Ash Formation from the Combustion of Coals with Maceral Concentrates at Various Pressures
Authors: Wu H. , Zhang D. K. , Kong C. , Wall T. F.
Published: August 2010

Two coal samples of different lithotypes and maceral‐enriched fractions were prepared (+6–0 m̈m) from samples of the same bituminous coal seam. Density separations at a specific gravity of 2.0 were applied for the prepared coal samples in order to remove the majority of the excluded mineral matter in the final coal samples. These coal samples were then pyrolysed or combusted in drop‐tube furnaces at 0.1 and 1.5 MPa to produce char and ash samples at 1573K. The results indicate that there are two main factors influencing char and ash formation under the experimental conditions, i.e. pressure and coal petrographic property. In agreement with our previous results, chars prepared at high pressure are more porous and ash particles are finer. The structure of the porous char particles at 0.1 and 1.5 MPa are very different, as evidenced by SEM surface observation. The porous char particles prepared at 1.5 MPa have a “foam” structure, while those at atmospheric pressure are mostly balloon‐like structures. The vitrinite‐rich coal produces a higher proportion of porous char particles during pyrolysis. Although the mineral particles in the vitrinite‐rich coal sample are coarser than those in the inertinite‐rich coal sample, the ash particles produced from the vitrinite‐rich coal after combustion are much finer. The results suggest that the extent of coalescence of included mineral matter of the inernite‐rich coal sample is more significant than that of the vitrinite‐rich coal sample. Char particles from the vitrinite‐rich coal sample are more porous compared to those from the inernite‐rich coal sample, leading to more intensive char fragmentation so that finer ash particles form during combustion. At 1.5 MPa, ash particles produced from both coals during combustion are finer than at atmospheric pressure, due to the char particle produced at 1.5 MPa being more porous. However, the sensitivity of the effect of pressure is less for the vitrinite‐rich coal sample.
Structural Characterisation of porous Char Particles by surface Observation Using a field Emission Scanning Electron Microscope
Authors: Wu H. , Kong C.
Published: August 2010

In this paper, porous char samples were examined using a Field Emission Scanning Electron Microscope (FESEM) at various accelerating voltages. Samples were examined as uncoated, gold coated and chromium coated. For uncoated samples, the images acquired at a low accelerating voltage tended to represent the surface structure and morphology while images obtained at high accelerating voltages typically reflected the internal char structure. Gold coating (∼20 nm) has a significant effect on the images obtained at high accelerating voltages compared to those obtained from uncoated particles. It is found that in the conventional SEM surface observation, which examines gold coated (∼20 nm) char particles at accelerating voltages of 10 kV or above, the images do not represent the surface but start to show the internal structure of the char particle. Chromium coating (∼2 nm) has little effect on the image formation, which could be a good candidate of coating for the surface observation of poorly/non‐conductive char particles. Such observations were determined by the char structure, the coating method, the properties of the coating material, the thickness of the material coated and the operating conditions of SEM surface observation. For porous char particles, a procedure of the structural characterisation for porous char particles using SEM surface observation has been proposed. The interpretations of the SEM images obtained for the porous char particles under various sample preparation and SEM operating conditions are also discussed
Simulating the Heat Transfer Process of Horizontal Anode Baking Furnace
Authors: Zhang L. Q. , Zheng C. G. , Xu M.H.
Published: August 2010

A transient two‐dimensional mathematical model of a horizontal baking furnace is presented. The model combines complex thermal phenomena in a baking process such as air infiltration, evolution and combustion of volatile matters, combustion of packing coke, and heat losses. The predicted results are in good agreement with measured data. Furthermore, the process is simulated under different operating conditions such as firing cycle time, airflow and air infiltration. The simulated results indicate that the fuel consumption decreases as the firing cycle time decreases, it is also found that reducing the airflow and air infiltration will help to save fuel. The model is proved to be a useful tool for the process optimisation of the baking furnace in the aluminum industry
Callus Induction from Tobacco (Nicotiana tabacum) Leaf Explants for the Production of Quinone
Authors: Husin Murnilawati Abd Gani , Hasan Masitah , Taha Rosna Mat
Published: August 2010

This paper reports the growth characteristics, measurement of fresh weight and dry weight of callus of tobacco (Nicotiana tabacum) cells grown on Murashige and Skoog (MS) medium supplemented with 2 mg/L NAA (naphtaleneacetic acid), 0.2 mg/L kinetin and 0.2 mg/L 2, 4‐D (2,4‐dichlorophenoxyacetic acid) at 25d̀C, under 16 hours light and 8 hours darkness. Leaf explants obtained from 3‐5 month old intact plants of tobacco were used to initiate cultures. MS medium supplemented with 2.0 mg/L NAA together with 0.2 mg/L kinetin gave rise to optimum callus induction.
The Effect of Chemical and Biopulping Process on Bagasse Pulp
Authors: Antaresti  , Sudaryanto Y. , Setiyadi  , Wibowo H. , Yogi  , Purnomo Y.
Published: August 2010

The amount of sugarcane bagasse in Indonesia is abundant while the utilization is still limited. One of the alternatives for bagasse utilization is as pulp material. To minimize the waste from the pulping process, the effect of using a chemical process (with nitric acid) and a biopulping process (using Fusarium solani) were studied and measured by the percentage of α‐cellulose content in bagasse pulp. In the chemical process, the nitric acid concentration and the reaction time were varied. The pulping process was conducted at constant temperature of 102d̀C and the mixture was agitated at 900 rpm. The highest percentage of α‐cellulose content in pulp was 79.28%, obtained at the concentration of 3.5% for a reaction time of 3.5 hours. At higher concentrations and longer cooking times, the α‐cellulose decreased due to the cellulose degradation. In the biopulping process, the incubation temperature was kept at 30d̀C. The highest percentage of α‐cellulose was 65.80% obtained at an incubation time of 25 days. When compared to nitric acid pulping, biopulping is less efficient. However it has one advantage that it only uses a small amount of chemicals and, therefore, creates less pollutants.
Performance of Dual‐Media Expanded Bed Bioreactor
Authors: Abdul‐Rahman R. , Zainol N. , Abu‐Bakar A.
Published: August 2010

Adsorption and biological treatment are two possible approaches to remove chloro‐organic and organic compounds. Granular activated carbon (GAC) biofilm reactors combine these two features, the adsorptive capacity and irregular shape of GAC particles providing niches for bacterial colonisation protected from high fluid forces, while the variety of functional groups on the surface enhance the attachment of microorganisms. The biofilm process is compact and offers reactions in both aerobic and anoxic states. Studies on removal of nitrogen constituents by a biofilm process were carried out using a dual‐media expanded bed bioreactor, with GAC and plastic media as support media. The plastic media also acts as a filter for the effluent. Experiments were carried out at F:M of about 0.45 and hydraulic residence times (HRT) of 48, 24 and 12 hours. Bed expansion was maintained at 20–30% by recirculation flow. Aerobic condition was maintained at dissolved oxygen (DO) of about 2 mg/l throughout the bed. Chemical oxygen in demand (COD) in feed was 1000 mg/L while the total‐N was 100 mg/L. Analysis showed that the process is able to maintain very stable conditions, achieving substantial COD removal of about 85% and total‐N removal of about 80%. Biofilm biomass measurements showed an increase from 400 mg/l at HRT of 48 hours to 10,100 mg/l at HRT 12 hours, showing that much higher biomass concentrations may be contained in a biofilm process as compared to a conventional suspended biomass process. Bioreactors contain their own ecosystems, the nature of the community and the state of microorganisms define the kinetics and determine reactor performance. Growth kinetic parameters obtained are YH = 0.3421 mg/mg, m̈H = 0.2252 day−1, KH = 319.364 mg/l and bH = 0.046 day−1. The denitrification kinetic parameters obtained are YHD = 0.9409 mg/mg, m̈HD = 0.1612 day−1, KHD = 24.6253 mg/l and bHD = 0.0248 day−1. These parameters enable prediction of required reactor sizes and operational parameters. The plastic media has greatly improved effluent clarification by 98% as compared to single‐media (GAC) only reactor.
Formation of Biofilm on Different Particulate Media Using Modified Kitchen Waste Extract as Initial Growth Substrate for Use in PCB Degradation
Authors: Auresenia J. , Ang S. , Espinosa D. , Juan J. , Borja J. , Taleon D.
Published: August 2010

This study describes the formation of biofilm on two different particulate media using modified kitchen waste extract as initial growth medium, and the subsequent testing of the this biofilm to biodegrade polychlorinated biphenyls (PCBs). Two parallel completely mixed fluidized bed reactors, one using cement balls and the other using sand as particulate media, were operated in order to produce the biofilm. Modified kitchen waste extract was used as a growth substrate instead of the more expensive complex substrate. The medium was inoculated with microorganisms from tannery wastes. Performance of the biofilms formed in the two reactors were compared based on BOD and COD degradation rates, biomass growth rate, biofilm thickness and ease offluidization. The results demonstrate that a stable biofilm can be formed on readily available particulate materials using cheap substrate from kitchen wastes extracts. Furthermore, cement balls proved to be more suitable as particulate media compared to sand, possessing superior biofilm‐forming characteristics. The biofilm formed on cement balls was tested for the degradation of PCBs. Initial PCB batch degradation tests showed that about 70% of PCBs degraded within six hours. Kinetics of PCB degradation followed the Monod model with Km = 561.98 mg/l and m̈max=0.07 1/h.
Treatment of Skim Latex Serum Using Gas Sparged Ultrafiltration
Authors: Harunsyah  , Sulaiman Nik Meriam , Aroua Mohamed Kheireddine
Published: August 2010

The major pollutants from a natural rubber processing factory have high organic content and emit an offensive smell due to the biodegradation of the organic matter. In latex concentrate factories, the main sources of effluent are the skim latex serum and washings from all process equipment. This paper presents an application of membrane technology that involves gas sparging for the treatment of skim latex serum. A semi‐pilot‐scale system using a PVDF vertical tubular membrane (MWCO 100,000) was installed as the experimental setup. Nitrogen gas was bubbled vertically upwards at flowrates ranging from 300 to 500 ml/min. Results obtained thus far show that gas sparging has increased the permeate flux between 1.37% and 146.34% compared to non‐gas sparged conditions. In terms of permeate quality, the reductions achieved for suspended solids, total solids, COD, BOD, total nitrogen and ammoniacal nitrogen were 83%, 95%, 67%, 77%, 51%, 74%, respectively, for the gas‐sparged condition. Under non gas‐sparging conditions, reductions achieved for suspended solids, total solids, COD, BOD, total nitrogen and ammoniacal nitrogen were 92%, 96%, 67%, 72%, 60%, 75%, respectively.
TiO2 Photoelectrodes for Water Splitting: Carbon Doping by Flame Pyrolysis?
Authors: Barnes P. R. F. , Randeniyaly L. K. , Murphy A. B. , Gwan P. B. , Plumb I. C. , Glasscock J. A. , Grey I. E. , Li C.
Published: August 2010

Titanium dioxide is often used as a photoelectrode material for water splitting, but its band gap is too wide to achieve high conversion efficiencies in sunlight. Flame oxidation (pyrolysis) of titanium sheet has been suggested as a method to produce carbon doped TiO2 with a reduced band gap. In the present study, films were prepared using this and other thermal oxidation techniques and the photoelectrochemical water splitting efficiency of the resultant materials was examined using a xenon lamp. The oxide films were characterised physically, optically and electrochemically. Incident photon conversion efficiency measurements indicated no significant reduction in the band gap offilms prepared using a hydrocarbon flame compared to rutile TiO2. Furthermore, these films were found to have an efficiency comparable to that offilms produced in a carbon free flame (hydrogen/oxygen). The results suggest that flame pyrolysis may not ‘dope’ TiO, with carbon in the manner previously proposed. Any enhancement in photocatalytic eficiency resulting from the technique is likely to be due to the formation of non‐stoichiometric TiO2 or titanium sub‐oxides.
Technology Options for Onboard Hydrogen Storage
Authors: Rufford T. E. , Zhu Z. H. , Lu G. Q.
Published: August 2010

The development of effective hydrogen storage systems remains a key technical challenge to the extensive use of hydrogen as an energy carrier. The most established methods of storing hydrogen are as a cryogenic liquid and as a high‐pressure compressed gas. However, these conventional technologies are restricted by the high energy cost of the liquefaction and compression processes, and by their low volumetric hydrogen densities. In the past 40 years considerable research efforts have focussed on the encapsulation of hydrogen in metal hydrides but the competitiveness of the higher capacity metal hydrides, such as the magnesium‐based alloys, has been hampered by sluggish sorption kinetics. In recent years hydrogen storage researchers have broadened the scope of potential materials under investigation to include complex hydrides and other advanced nanomaterials, such as nanostructured carbons and metal‐oxide frameworks. This paper presents a review of the most mature of the hydrogen storage technologies, being compressed gas, clyogenic liquid and metal hydrides. and discusses promising directions in the search for suitable hydrogen storage materials.
Proton Conductivities of Titanium Phosphate at High Temperature for PEMFC
Authors: Tran A. T. T. , Duke M. , Diniz Costa J. C. Da , Gray P. G.
Published: August 2010

Titanium phosphate was synthesized fiom tetra iso‐propoxide (TTIP, Aldrich) and H3PO4 with a Ti/P molar ratio of 1:9 by sol gel method. A maximum proton conductivity value of 5.4 x 102 S.cm−1 at 20°C and 93% relative humidity (RH) was achieved. The high proton conductivity is related to the existence of the hydrogen bonding in POH groups and the water molecules in the gel structure which was confirmed by thermo gravimetric analysis (TGA). The conductivity increased with relative humidity, indicating that the Grotthuss was the main proton transport mechanism. Moreover, the proton conductivity increased with the temperature with the value of ∼10−1 S.cm−1at 200°C and 0.5% RH. The presence of water molecules and an excess of phosphoric acid in the gel matrix, which were confirmed by TGA and FTIR analysis, contributed to high proton conductivity at high temperature and low humidiity.
Variability in Transport Properties for Blackbutt Timber in New South Wales: Within and Between‐Tree Variability
Authors: Cabardo S. J. , Edxau D. , Langrish T. A. G.
Published: August 2010

Variability is a key issue in the processing of biological materials, in this case the hying of hardwood timber. This paper reports the measurements of variability of transport properties. which are relevant to the drying of blackbutt, Eucalyptus pilularis Sm, from northern New South Wales. Specifically, within‐tree and between‐tree variations are reported for two blackbutt regrowth logs. An analysis of variance showed that some timber properties were affected by the board positions within‐trees and between‐trees. Circumferential and radial efects were significant for the within‐ tree variability of most transport properties. Similarly, radial and circumferential effects were signlficant for most of the transport parameters between trees, but can be tentatively stated because only two regrowth logs were assessed. Timber boards with high initial moisture contents had higher rates of diffirsion and low basic densities using principal components analysis. A possible reason is that if there is less wood material per unit volume, these vacant spaces may be occupied by water, and there is also less resistance for diffusive transport of moisture.
Development and Validation of an Unsteady State Numerical Model of Fouling within a Crystalline Systern
Authors: Walker P. G. , Sheikholeslami R.
Published: August 2010

Fouling is a phenomenon that threatens the sustainability of thermal and membrane desalination processes. The deposition of fouling material on the heatlmass transfer surface increases the amount of energy required for operation. Traditional fouling research has focused on experimental investigations that provide limited results and macroscopic assessment of the process. This research uses computational fluid dynamics (CFD) to model the transient nature of fouling and obtains an insight into the intricate interactions of the variables that influence fouling on a local scale.

The authors developed a Eulerian model describing both the induction and deposition processes of the crystallisation fouling mechanism. The detail provided by the CFD model demonstrated that scale growth has a considerable impact on the hydrodynamics of the system, and vice‐versa. The intricate relationships between the operating variables affect the hydrodynamics and boundary layer conditions, and impact on both the heat and mass transfer. The deposit growth causes a decrease in the thickness of the mass boundary layer, thus promoting transport towards the growing crystal layer. Validation of this model showed good agreement with experimental data in terms of its ability to predict local fouling behaviour and rates.
Metallurgical Characteristics and Effectiveness of Metallic Charges in Electric Arc Furnace
Authors: Du Cheng‐Wu , Zhu Miao‐Yong , Sun Li‐Na , Dong Shi‐Ze
Published: August 2010

The use of direct reduced iron (DRI), hot metal, cold pig iron, decarburized granular iron, iron carbide, and complex metal charges to replace scrap metal as the feedstock to an electric arc furnace not only resolves the lack of scrap supply, but is also very helpful in diluting the residual elements in the scrap, thus improving the quality of the steel. It has now become possible to produce high‐quality steel in an electric arc furnace. In this paper, the characteristics and effectiveness of various metallic charges for use in an electric arc furnace (EAF) are discussed.
Effect of Refining Slag Composition on Inclusions in Molten Steel treated by Barium‐bearing Alloy
Authors: Li Yang , Jiang Zhou‐Hua , Liu Yang
Published: August 2010

The effect of the refining slag composition on the inclusions in molten steel was studied in MgO crucible by using MoSi2 furnace. The experimental steel was heavy rail steel and Si‐Ca‐Ba alloy was used as the deoxidizer. The results showed that the total oxygen content of steel, and the total quantities, total areas and average radius of inclusions decreased with the increased basicity of refining slag. The total quantities and total areas of inclusions were the least when Al2O3 content in refining slag was between 13% and 20%, while the proportion of small inclusions increased when Al2O3 content was higher than 20%. The contents of SiO2 and Al2O3 in inclusions were affected directly by the SiO2 and Al2O3 contents in refining slag, and it was very remarkble when the slag composition was CaOAl2O32SiO2. Therefore, it's feasible to control the composition of inclusions by controlling the composition of refining slag.
Study on Lubrication and Friction between Strand and Mould in Continuous Slab Casting
Authors: Yao Man , Wang Xu‐Dong , Du Bo
Published: August 2010

Due to improved requirements for high casting speed, slab quality, variety of steel in continuous casting, it is increasingly important to accurately control the mould/strand lubrication and friction behavior. In this study, by means of combining analysis of the measured friction data from plant trials with numerical calculations, an empirical formula for the friction coefficient of strand/mould is obtained. The mathematical model is established in order to determine the strand/mould lubrication and friction behavior, and to obtain the profiles of thickness and internal pressure of liquid slag film, and the distribution of liquid friction between strand and mould. These values enable calculation of the local mould friction. It was found that mould friction increased when some cracks and breakouts take place, thus showing that the influence of mould friction on mechanical behavior of the solidified shell as well as the thermal stress are taken into account.
Utilization of Metallurgical Slag as Resource Materials in China
Authors: Shen Jian‐Guo , Guo Chun‐Yuan , Chen Min , Yu Jing‐Kun , Jiang Mao‐Fa
Published: August 2010

New developments that utilize metallurgical slag as resource materials are important in order to decrease the land used for disposal of slag, reducing environmental pollution, and also promoting the continuous and highly efficient development of China's metallurgical industry. Current major problems and possible future uses of metallurgical slag are discussed based on assessments of present uses. Improving the use of metallurgical slag as resource materials requires the development of new high‐value‐added products.
Prediction of Scale Formation Problems in Oil Reservoirs and Production Equipment due to Injection of Incompatible Waters
Authors: Moghadasi J. , Sharif A. , Müuller‐Steinhagen H. , Jamialahmadi M.
Published: August 2010

In this paper, the mechanisms of scale formation from oilfield water are presented. An accurate model for predicting the scaling phenomena due to mixing of incompatible waters, changes in thermodynamic, kinetic and/or hydrodynamic conditions in oilfield operations is suggested. This model can predict scaling tendency of common oilfield waters in disposal wells, water‐flooding systems and in surface equipment and facilities. The model is developed based on experimental data and empirical correlations, which match the oil field conditions accurately. Furthermore, the simultaneous deposition of different oilfield scales and the competition of various ions to form scale are incorporated in the model. The suggested model has been used to investigate the potential for scale precipitation in various Iranian on‐shore and off‐shore oil fields, where water injection is being performed for the water disposal of desalting units or as a method of secondary recovery or reservoir pressure maintenance.
The Biosynthesis of the Aroma Volatile 2‐Methyltetrahydrothiophen‐3‐one in the Bacterium Chitinophaga Fx7914
Authors: Nawrath Thorben , Gerth Klaus , Müller Rolf , Schulz Stefan
Published: August 2010

2‐Methyltetrahydrothiophen‐3‐one (3) is a volatile compound that plays an important role especially in food and flavour chemistry because it contributes to the aroma of several foodstuffs including wine. Although 3 can be formed by chemical reactions during food preparation, it is also produced by microorganisms. Recent studies with yeasts showed that methionine (1) is a potential precursor of 3, but the mechanism of the transformation is unknown. The biosynthetic pathway leading to 3 in the bacterium Chitinophaga Fx7914 was probed. Extensive feeding experiments with differently labelled precursors by using liquid cultures of Chitinophaga Fx7914 were performed. The volatiles released by the bacterium were collected by using a closed loop stripping apparatus (CLSA) and analysed by GC–MS. The observed incorporation pattern of the precursors into 3 led to the elucidation of the biosynthetic pathway. One part of the compound 2 originates from homocysteine (15), which is transformed into 3‐mercaptopropanal (17). The second biosynthetic building block is pyruvate (14). An acyloin‐forming reaction furnishes the key intermediate 21, which cyclises intramolecularly to a diol. Dehydration followed by tautomerisation lead to the cyclic ketone 3, which is produced by the bacterium in racemic form.
ChemInform Abstract: Molecular Structure and Vibrational Spectra of 9‐Fluorenone Density Functional Theory Study.
Authors: LEE S. Y. , BOO B. H.
Published: August 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Asymmetric Cyclization of Unsaturated Alcohols and Carboxylic Acids with Camphor‐Based Selenium Electrophiles.
Authors: BACK T. G. , DYCK B. P.
Published: August 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Triflate/Mesylate Ratios and Competing C‐O and S‐O Bond Cleavages in Nucleophilic Vinylic Substitution.
Authors: SCHOTTLAND E. Z. , RAPPOPORT Z.
Published: August 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.