bluuebunny/crossref_metadata_2025 huggingface dataset:
Manganese Provides Antioxidant Protection for Sperm Cryopreservation that May Offer New Consideration for Clinical Fertility
Authors: Cheema Ranjna S. , Bansal Amrit K. , Bilaspuri Gurmail Singh
Published: August 2010

Reactive oxygen species (ROS) are generated by sperm metabolism. While, ROS are required for maturation, capacitation and acrosome reaction, they also modify many peroxidable cellular compounds. There is production of ROS during cryopreservation and frozen spermatozoa are highly sensitive to lipid peroxidation (LPO). Antioxidants exert a protective effect on the plasma membrane of frozen bovine sperm preserving both metabolic activity and cellular viability. Manganese (Mn++) is proved to be a chain breaking antioxidant in biological system. Therefore, we examined the role of (Mn++) during cryopreservation of cattle bull semen. Semen was divided into four parts and cryopreserved in egg‐yolk‐citrate extender + glycerol (EYC‐G), EYC‐G + 100 µM of Mn++, EYC‐G + 150 µM of Mn++ and EYC‐G + 200 µM of Mn++. After four hours of cooling and 24 hrs of freezing, the spermatozoa were examined for percentage motility, Hypo‐osmotic swelling (HOS), LPO and protein leakage. Addition of manganese to the semen during cryopreservation showed a protective effect and accounted for an increase in semen quality parameters [percentage motility, HOS percent and decrease in malondialdehyde (MDA) production and protein leakage]. The effect of manganese on motility and HOS was non‐significant (p < 0.05) in cooled spermatozoa but significant with 150 µM of Mn++ in frozen‐thawed spermatozoa. MDA production and protein leakage decreased to a significant and maximum level (p < 0.05) on addition of 200 µM of manganese. The addition of manganese to EYC‐G dilutor will improve the quality/fertility of semen, which will result in improvement of in vitro fertilization and artificial insemination success rate.
Oxidative Stress in The Hippocampus During Experimental Seizures Can Be Ameliorated With The Antioxidant Ascorbic Acid
Authors: Santos Ítala Mônica Sales , Tomé Adriana da Rocha , Saldanha Gláucio Barros , Ferreira Paulo Michel Pinheiro , Militão Gardenia Carmem Gadelha , de Freitas Rivelilson Mendes
Published: August 2010

Ascorbic acid has many nonenzymatic actions and is a powerful water‐soluble antioxidant. It protects low density lipoproteins from oxidation and reduces harmful oxidants in the central nervous system. Pilocarpine‐induced seizures have been suggested to be mediated by increases in oxidative stress. Current studies have suggested that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures. The objective of the present study was to evaluate the neuroprotective effects of ascorbic acid (AA) in rats, against the observed oxidative stress during seizures induced by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group), ascorbic acid (500 mg/kg, i.p., AA group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of ascorbic acid (500 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min before of administration of ascorbic acid (AA plus pilocarpine group). After the treatments all groups were observed for 6 h. The enzyme activities as well as the lipid peroxidation and nitrite concentrations were measured using spectrophotometric methods and the results compared to values obtained from saline and pilocarpine‐treated animals. Protective effects of ascorbic acid were also evaluated on the same parameters. In pilocarpine group there was a significant increase in lipid peroxidation and nitrite level. However, no alteration was observed in superoxide dismutase and catalase activities. Antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content as well as increased the superoxide dismutase and catalase activities in hippocampus of adult rats after seizures induced by pilocarpine. Our findings strongly support the hypothesis that oxidative stress in hippocampus occurs during seizures induced by pilocarpine, proving that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and also imply that a strong protective effect could be achieved using ascorbic acid.
Oral Administration of L‐Arginine in Patients With Angina or Following Myocardial Infarction May Be Protective By Increasing Plasma Superoxide Dismutase and Total Thiols With Reduction in Serum Cholesterol and Xanthine Oxidase
Authors: Tripathi Pratima , Chandra M. , Misra M. K.
Published: August 2010

Administration of L‐arginine has been shown to control ischemic injury by producing nitric oxide which dilates the vessels and thus maintains proper blood flow to the myocardium. In the present study attempt has been made to determine whether oral administration of L‐arginine has any effect on oxidant/antioxidant homeostasis in ischemic myocardial patients [represented by the patients of acute angina (AA) and acute myocardial infarction (MI)]. L‐arginine has antioxidant and antiapoptotic properties, decreases endothelin‐1 expression and improves endothelial function, thereby controlling oxidative injury caused during myocardial ischemic syndrome. Effect of L‐arginine administration on the status of free radical scavenging enzymes, pro‐oxidant enzyme and antioxidants viz. total thiols, carbonyl content and plasma ascorbic acid levels in the patients has been evaluated. We have observed that L‐arginine administration (three grams per day for 15 days) resulted in increased activity of free radical scavenging enzyme superoxide dismutase (SOD) and increase in the levels of total thiols (T‐SH) and ascorbic acid with concomitant decrease in lipid per‐oxidation, carbonyl content, serum cholesterol and the activity of proxidant enzyme, xanthine oxidase (XO). These findings suggest that the supplementation of L‐arginine along with regular therapy may be beneficial to the patients of ischemic myocardial syndromes.
Redox Regulation in Cancer: A Double‐edged Sword with Therapeutic Potential
Authors: Acharya Asha , Das Ila , Chandhok Des , Saha Tapas
Published: August 2010

Oxidative stress, implicated in the etiology of cancer, results from an imbalance in the production of reactive oxygen species (ROS) and cell’s own antioxidant defenses. ROS deregulate the redox homeostasis and promote tumor formation by initiating an aberrant induction of signaling networks that cause tumorigenesis. Ultraviolet (UV) exposures, γ‐radiation and other environmental carcinogens generate ROS in the cells, which can exert apoptosis in the tumors, thereby killing the malignant cells or induce the progression of the cancer growth by blocking cellular defense system. Cancer stem cells take the advantage of the aberrant redox system and spontaneously proliferate. Oxidative stress and gene‐environment interactions play a significant role in the development of breast, prostate, pancreatic and colon cancer. Prolonged lifetime exposure to estrogen is associated with several kinds of DNA damage. Oxidative stress and estrogen receptor‐associated proliferative changes are suggested to play important roles in estrogen‐induced breast carcinogenesis. BRCA1, a tumor suppressor against hormone responsive cancers such as breast and prostate cancer, plays a significant role in inhibiting ROS and estrogen mediated DNA damage; thereby regulate the redox homeostasis of the cells. Several transcription factors and tumor suppressors are involved during stress response such as Nrf2, NFκB and BRCA1. A promising strategy for targeting redox status of the cells is to use readily available natural substances from vegetables, fruits, herbs and spices. Many of the phytochemicals have already been identified to have chemopreventive potential, capable of intervening in carcinogenesis.
GOME-2 observations of oxygenated VOCs: what can we learn from the ratio glyoxal to formaldehyde on a global scale?
Authors: Vrekoussis M. , Wittrock F. , Richter A. , Burrows J. P.
Published: August 2010

Abstract. Collocated data sets of glyoxal (CHO.CHO) and formaldehyde (HCHO) were retrieved for the first time from measurements of the Global Ozone Monitoring Experiment-2 (GOME-2 during the first two years of operation in 2007 and 2008. Both oxygenated Volatile Organic Compounds, OVOC are key intermediate species produced during the oxidation of precursor hydrocarbons. Their short lifetime of a few hours in the lower troposphere links them to emission sources and makes them useful tracers of photochemical activity. The global composite maps of GOME-2 HCHO and CHO.CHO have strong similarities confirming their common atmospheric and/or surface sources. The highest column amounts of these OVOCs are recorded over regions with enhance biogenic emissions (e.g. tropical forests) in South America, Africa and Indonesia). Enhanced OVOC values are also present over areas of anthropogenic activity and biomass burning (e.g. over China, N. America, Europe and Australia). The ratio of CHO.CHO to HCHO, RGF, has been used, for the first time on a global scale, to classify the sources according to biogenic and/or anthropogenic emissions of the precursors; RGF between 0.040 to 0.060 point to the existence of biogenic emissions with the highest values being observed at the highest Enhanced Vegetation Index, EVI. RGFs below 0.040 are indicative of anthropogenic emissions and associated with high levels of NO2. This decreasing tendency of RGF with increasing NO2 is also observed when analyzing data for individual large cities, indicating that it is a common feature. The results obtained for RGF from GOME-2 data are compared with the findings based on regional SCIAMACHY observations showing good agreement. This is explained by the excellent correlation of the global retrieved column amounts of CHO.CHO and HCHO from the GOME-2 and SCIAMACHY instruments for the period 2007–2008.
Ozone, Carbon monoxide and Nitrogen oxides time series at four Alpine GAW mountain stations in Central Europe
Authors: Gilge S. , Plass-Duelmer C. , Fricke W. , Kaiser A. , Ries L. , Buchmann B.
Published: August 2010

Abstract. Long-term, ground based in-situ observations of Ozone (O3) and its precursor gases Nitrogen dioxide (NO2) and Carbon monoxide (CO) from the four sites Hohenpeissenberg and Zugspitze (D), Sonnblick (A) and Jungfraujoch (CH) are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA) procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3) or CO standards provided by the Central Calibration Laboratory (CCL) at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC) for CO and O3 (WCC-Empa; CH). Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites. This was observed independent of wind sector and for most seasons, with a tendency to higher positive trends in winter and lower and partly negative trends in summer. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the highest rate of O3 increase was detected in winter and lowest in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti-correlation with NO2, was found due to reduced O3 values on working days. Trends are discussed with respect to anthropogenic impacts and vertical mixing. The observed trends for NO2 at the alpine mountain sites are less pronounced than trends estimated based on emission inventories.
Rapid changes in ice core gas records – Part 1: On the accuracy of methane synchronisation of ice cores
Authors: Köhler P.
Published: August 2010

Abstract. Methane synchronisation is a concept to align ice core records during rapid climate changes of the Dansgaard/Oeschger (D/O) events onto a common age scale. However, atmospheric gases are recorded in ice cores with a log-normal-shaped age distribution probability density function, whose exact shape depends mainly on the accumulation rate on the drilling site. This age distribution effectively shifts the mid-transition points of rapid changes in CH4 measured in situ in ice by about 58% of the width of the age distribution with respect to the atmospheric signal. A minimum dating uncertainty, or artefact, in the CH4 synchronisation is therefore embedded in the concept itself, which was not accounted for in previous error estimates. This synchronisation artefact between Greenland and Antarctic ice cores is for GRIP and Byrd less than 40 years, well within the dating uncertainty of CH4, and therefore does not calls the overall concept of the bipolar seesaw into question. However, if the EPICA Dome C ice core is aligned via CH4 to NGRIP this synchronisation artefact is in the most recent unified ice core age scale (Lemieux-Dudon et al., 2010) for LGM climate conditions of the order of three centuries and might need consideration in future gas chronologies.
Sediment management modelling in Blue Nile Basin using SWAT model
Authors: Betrie G. D. , Mohamed Y. A. , van Griensven A. , Srinivasan R. , Mynett A.
Published: August 2010

Abstract. Soil erosion/sedimentation is a colossal problem that has menaced water resources development in the Nile, particularly in Eastern Nile (Ethiopia, Sudan and Egypt). An insight into soil erosion/sedimentation mechanism and mitigation methods plays an indispensable role for the sustainable water resources development in the region. This paper presents a daily sediment yield simulation in the Upper Blue Nile under different Best Management Practices (BMPs) scenarios. The scenarios were baseline (existing condition), Buffer strips, stone bund (parallel terrace), and reforestation. The Soil and Water Assessment Tool (SWAT) was used to model soil erosion, identify soil erosion prone areas and assess the impact of BMPs on sediment reduction. The study found satisfactory agreement between daily observed and simulated sediment concentration with Nash-Sutcliffe efficiency (NSE)=0.88, percent bias (PBIAS)=−0.05%, and ratio of the root mean square error to the standard deviation of measured data (RSR)=0.35 for calibration and NSE=0.83, RSR=0.61 and PBIAS=−11% for validation. The sediment yield for baseline scenario was 117×106 t yr−1. The buffer-strips, stone-bund and reforestation reduced the sediment yield at outlet of the Upper Blue Nile basin by 44%, 41% and 11%, respectively. The sediment reduction at subbasins outlets varied from 29% to 68% by buffer strip, 9% to 69% by stone-bund and 46% to 77% by reforestation. This study clearly demonstrates the efficacy of catchment management intervention (BMPs) for sustainable water resources development in the Eastern Nile basin.
Flow and mixing around a glacier tongue
Authors: Stevens C. L. , Stewart C. L. , Robinson N. J. , Williams M. J. M. , Haskell T. G.
Published: August 2010

Abstract. A glacier tongue floating in the coastal ocean presents a significant obstacle to the local flow and influences oceanic mixing and transport processes. Here ocean shear microstructure observations at a glacier tongue side-wall show tidally-induced flow pulses and vortices as well as concomitant mixing. Flow speeds within the pulses reached around three times that of the ambient tidal flow amplitude and generated vertical velocity shear as large as 3×10−3 s−1. During the maximum flow period turbulent energy dissipation rates reached a maximum of 10−5 m2 s−3, around three decades greater than local background levels. This is in keeping with estimates of the gradient Richardson Number which dropped to around unity. Associated vertical diffusivities are higher that expected from parameterization, possibly reflecting the proximity of the cryotopography.
Industrial Electrochemical Synthesis Processes: Recent Developments in Reactor Design
Authors: Scott K.
Published: August 2010

This review considers the design methods and recent developments in reactor selection for industrial electrochemical synthesis. The scope of electrosynthesis is reviewed, together with the reactor technology required to provide commercially viable operation. Improvements in reaction engineering techniques as applied to electrochemical synthesis, both inorganic and organic, will continue to provide developments in this valuable and important sector of the process industries.

Part I provides a classification of electrochemical synthesis reactions in terms of direct and indirect processes, and reviews the application of electrosynthesis in the production of organic and inorganic chemicals.

Part II considers the important design factors in the development of electrochemical processes and their limitations. These include aspects of productivity, energy requirements, mass transport, electrode and membrane materials.

Part II The final part of this review describes the design of electrochemical reactors used for both organic and inorganic synthesis, to ensure that the electrochemical cell is an efficient and economic unit for industrial use. The designs include reactors which use either two‐dimensional or three‐dimensional electrodes. Recent examples of the use of such reactors are described. A brief overview of reaction engineering principles is included in the context of both single‐phase and two‐phase fluid systems.
Kinetic Study of Synthesising 2,4,6‐tribromophenyl Benzyl Ether by Phase Transfer Catalysis
Authors: Wang Maw‐Ling , Hsieh Yu‐Ming
Published: August 2010

The reaction of 2,4,6–tribromophenol and benzyl bromide in an alkaline solution of KOH/organic solvent by phase transfer catalysis was studied. The main product C6H5CH2O(C6H2)Br3 and the intermediate product Bu4N‐0(C6H2)Br3 were synthesised, and subsequently identified analytically. The kinetics of the reaction were studied in detail. The effects of the operating conditions such as agitating speed, amount of catalyst, types of solvent and catalyst, salt effects, amount of water, mole ratio of benzyl bromide to 2,4,6–tribromophenol, content of KOH and temperature, on the conversion and the reaction rates were investigated. The negligible mass‐transfer resistance of the catalyst between the two‐phase reaction was indirectly identified from experimental observations. The organic‐phase reaction is the rate‐controlling step for the two‐phase reactions. During the reaction, a constant concentration of the intermediate product was obtained in the organic phase. Therefore, a pseudo‐first‐order rate law can be applied to describe the two‐phase reaction. The activation energy for this reaction system was obtained as 18.31 kcal mol−1.
A General Relationship for Gas‐Liquid Mass Transfer with Various Geometries
Authors: Herron W. , Spedding P.L. , Buchanan R.H.
Published: August 2010

Mass transfer in packed columns, wetted wall towers and from plane horizontal surfaces has been shown to be adequately predicted by theory, providing extraneous effects are handled correctly. The mass transfer can be correlated using a Gilliland‐Sherwood type formula in which the relative velocity between the phases at the interface is the important parameter. The correlation applies regardless of the geometry of the system, and provides a general mechanism for estimation of the mass transfer within equipment. Such an approach allows for estimation of the actual transfer taking place in mass transfer equipment without resource to estimation of stage efficiencies, and should eliminate the need, for example, for the Murphree stage efficiency.
The Measurement of High Pressure Vapour‐Liquid‐Equilibria: Part I: Dynamic Methods
Authors: Raal J. D. , Mühlbauer A. L.
Published: August 2010

Accurate measurement of high pressure vapour‐liquid equilibria is a most demanding task and has elicited much effort and ingenuity from researchers. The number and variety of approaches adopted attest to the exacting nature of the task of finding the most reliable, accurate and cost‐effective approach. There is as yet no firm consensus of opinion as to which type of equipment is superior. Each type has its advantages and drawbacks and persuasive advocates. There are few areas of research in chemical engineering or physical chemistry in which so great a variety of equipment and techniques has been reported. The purpose of this publication is to summarize in some detail the equipment and procedures used to measure high pressure VLE and to comment on some of the difficulties common to several methods. In Part I we discuss dynamic measurement methods and refer to a new high‐precision volumetric device we have developed for gas chromatograph calibration for gas mixtures or for gas‐liquid mixtures. In Part II we examine static methods for high pressure VLE measurement and present proposals for a new cell suitable for multiphase equilibrium and volumetric data measurement.

A complete survey of the numerous types of equipment used and proposed is not feasible within reasonable length. Good reviews by Tsiklis[1] (1968) and Young[2] (1978) in particular are available, and our emphasis is on more recent developments. This review will be useful to those entering the field or those experiencing problems with a particular type of apparatus.
Separation of Chromium Ions through supported Liquid Membranes and Membrane Reactors
Authors: Scott K. , Ibhadon A.
Published: August 2010

The use of supported liquid membranes (SLM) for the selective separation of chromium ions from aqueous solutions is described. Flat‐sheet microporous polypropylene membranes loaded with Aliquat 336 in o‐xylene are used. The use of liquid membranes in electrochemical membrane reactors is also considered. Cell performance with and without separation are compared. The process has potential applications in recycling and for indirect electrochemical oxidations of organic compounds.
Effect of substituent on the Performance of Cupferron as a Collector for Uranium
Authors: Nirdosh I. , Muthuswami S.V. , Natarajan R. , Jeyaraman R.
Published: August 2010

Cupferron derivatives were synthesized and wed as collectors for uranium in the bench‐scale flotation of a uranium ore from Cluff Lake, Saskatchewan, Canada. All the derivatives were found to be more effective than cupferron itself. For alkyl‐substituted cupferrons, uranium recovery increased with an increase in alkyl chain length, with p‐nonylcupferron having a uranium recovery of 82% in 25% floated mass. Among the halogen‐substituted cupferrons, para‐substituted compounds performed better than meta‐substituted compounds. Although uranium recovery was only 50%, in the case of p‐methoxycupferron, the mass floated was as low as 8% of the feed. Separation efficiencies were correlated with Hammett sigma values.
Synthesis of Mass‐Exchange Networks with Multiple Target Mass‐Separating Agents
Authors: Garrison G. W. , Cooley B. L. , El‐Halwagi M. M.
Published: August 2010

A systematic procedure is developed for the simultaneous synthesis of primary mass‐exchange networks and their associated regeneration systems, The purpose of the mass‐exchange network is to preferentially transfer certain pollutants from a set of rich streams to a set of lean streams. The regeneration system subsequently regenerates any recyclable lean stream. In this work, we account for the possibility of each mass‐separating agent to split into a number of substreams with different target compositions. Accounting for this possibility of multiple target mass‐separating agents introduces additional design degrees of freedom which can provide a significant economic benefit. A mixed integer nonlinear program is formulated and solved to minimize the operating cost of both networks simultaneously. The solution of this program provides the optimal flow rates and composition ranges of all lean and regenerative streams without any prior commitment to the network structure. Subsequently, a network is synthesized to minimize the fixed cost while realizing the minimum operating cost.
Tert‐Butyl Ethers ‐ A Comparison of Properties, Synthesis Techniques and Operating Conditions for High Conversions
Authors: Sneesby M. G. , Tadé M. O. , Datta R.
Published: August 2010

Methyl tert‐butyl ether (MTBE) is currently the industrially dominant ether oxygenate although ethyl tert‐butyl ether (ETBE) is growing in importance as an alternative. ETBE has superior oxygenate properties (lower RVP and higher octane) and can be made from renewable ethanol. The ETBE reaction system is thermodynamically more restrictive than MTBE and the increased relative volatility of the ethanol‐isobutylene system compared with the methanol‐isobutylene system makes operation of a reactive distillation column more difficult. In this paper, the advantages of reactive distillation for tertiary ether production are discussed. Twenty different reactive distillation column configurations are identified with different designs being preferred for ETBE and MTBE. The effects of eight key operating criteria in reactive distillation systems are briefly discussed. Finally, reactive distillation systems producing MTBE and ETBE are simulated using Pro/II ver 4.0 to demonstrate that high conversions are possible for both products with relatively simple equipment.
Characterisation of Through‐Flowing Pores in Activated Carbon Pellets by the Method of Time‐Lag
Authors: Rutherford S. W. , Nguyen C. , Do D.D.
Published: August 2010

Pellets of finely sized activated carbon particles prepared in our laboratory and tailored to have differing BET surface areas were constructed. The time‐lag technique was employed to investigate the mass transfer of non‐sorbing and weakly sorbing gases in these pellets. This involved subjecting the pellet to known upstream pressure, and the pressure rise in the downstream volume (which was initially outgassed) was monitored. The diffusion coefficient representing the mass transfer into the particle network was found to be a complex Junction of the system parameters for all gases including helium, indicating the possibility of surface diffusion with Helium or that pellet heterogeneity affects the diffusion process. However, the molecular weight dependence of the observed flux is close to that predicted by the Knudsen diffusion equation, allowing the pores to be sized.
Drag Reduction in Two‐phase Gas‐Liquid flow
Authors: Ferguson M. E. G. , Spedding P. L.
Published: August 2010

Drag reduction is reported for two phase air water liquid co‐current flow for three different pipe diameters (0.0454, 0.0508, 0.0935 m). The drag reduction was achieved without the addition of drag reducing agents such as surfactants. Drag reduction compared to single phase gas flow occurred in the stratified and the stratified plus ripple regimes and in the droplet and the stratified film plus droplet regimes at low liquid flow rates. Drag reduction compared to single phase liquid flow occurred in the stratified and the stratified roll wave and inertial wave and the bubble flow regimes at relatively low gas flows. Details of the mechanisms involved are presented.
Crystal Size Distribution Control in Reactive Precipitation Processes
Authors: ZareNezhad B.
Published: August 2010

Crystallization of boric acid through reaction between borax solution and oxalic acid crystals was investigated experimentally. The infruence of process variables on the product mean crystal size and number concentration was presented. Larger crystals were produced at low ranges of borax Concentration, solid oxalic acid loading and impeller speeds, and high temperatures and large oxalic acid crystals.
Mass Transfer at Horizontal Surfaces in Bubble Columns
Authors: Nosier S. A. , El‐Khaiary M. I.
Published: August 2010

The solid‐liquid mass transfer characteristics of a single cylindrical horizontal surface immersed in a gas‐liquid bubble column were investigated by measuring the rate of dimion‐controlled dissolution of a copper surface in acidified dichromate solution. Variables studied were the diameter of the cylindrical surface, physical properties of the solution, and airflow rate. The mass tranfer coefficient was found to increase with increasing air flow rate. Increasing the diameter was found to decrease the mass transfer coefficient. The mass transfer data were correlated by the equation: J = 0.147 (Fr Re)0.256 (dide)−0.235. It was found that the diameter does not have a significant effect on the gas holdup.
Emission Control of VOC Components in Gasoline with Oxygenates: A Comparative Study
Authors: Furzer I. A.
Published: August 2010

A new characterisation method for VOC emissions is proposed for gasolines containing oxygenates such as methanol, ethanol and MTBE. The method is based on determining the vapour composition of an oxygenated gasoline that contains 10% (mol) oxygenate, and 10% (mol) is vaporised. A simulation of the method for a PNA gasoline with oxygenates gave the characteristic vapour composition for methanol, ethanol and MTBE as 0.536, 0.196 and 0.243(mol frac) respectively. Major VOC emissions may be expected in oxygenated gasolines containing methanol.
Heat Transfer to Liquid/Solid Fluidized Beds in Cylindrical Pipes
Authors: Jamialahmadi M. , Malayeri M. R. , Müller‐Steinhagen H.
Published: August 2010

Bed voidage and local heat transfer coefficients for liquid/solid fluidized beds in a cylindrical tube have been measured using water as liquid phase, and three sizes of cylindrical steel particles as well as glass, nickel, copper and lead spheres as solid phase. The independent variables included heat flux, liquid velocity and particle physical properties. Conclusive interpretation of the results was possible with the recently published model of Gibilaro et al. which was used to define the hydrodynamic behaviour of the fluidized beds. During particulate fluidization and in the transition zone, bed voidage and heat transfer coefficient are strongly dependent on particle size and particle density. Alternatively, bed voidage and heat transfer coefficient during aggregate fluidization are almost independent of particle size and particle density. The maximum heat transfer rate is observed at voidage of 0.7–0.75 which correspond to the point of maximum aggregation in the bed. The measured heat transfer coefficients are compared with published correlations.
Treatment of Winery Wastewater In A Reactive PU‐Immobilized Anaerobic Fluidized Bed Reactor
Authors: Peng R. Y. , Cheng C. , Greenfield P. F. , Wang H. E.
Published: August 2010

Immobilization of methanogens through direct reactive polymerization of TDI (tolylene diisocyanate) and PPG (polypropylene glycol) was shown to be successful. Rapid and early startup occurred within 48 hours of immobilization, with methane production rate 12.6 L/L‐day. In treating synthetic wastewater (SW), maximum percent sugar and COD eliminations at influent sugar loadings 4 g/L and 2 g/L were found to be 98.5% and 91.3 % respectively at hydraulic retention time (HRT) of 250 min. Whereas in treating winery wastewater (WW) at the same HRT, the treatment efficiency for sugar; protein; and COD was 94.1%; 90.3%; and 84.25%, respectively. While the methane production rate reached 8.75 L/L‐day. The features of direct reactive polyurethane(PU) ‐immobilization can be considered to be feasible as a new process innovation.
A Study of the Rapid Thermal Annealing Process for PECVD‐Deposited Borophosphosilicate Glass
Authors: Naimpally A.
Published: August 2010

A study of the flow behavior of PECVD‐deposited borophosphosilicate glass has been conducted The flow that occurs due to the rapid thermal annealing process was measured for several concentrations of boron and phosphorus, as well as for different heights of the glass. The flow angle increases with the concentrations of boron and phosphorus, and increases in the height of the glass. The results will prove useful to process engineers trying to achieve flow with low thermal loads using rapid thermal annealing.
Process Synthesis for a Reactor‐Separator‐Recycle System using the Attainable Region Approach
Authors: Mcgregor C. , Hildebrandt D. , Glasser D.
Published: August 2010

The optimisation of a system of reactors and separators with recycle is an important problem in chemical engineering. This work examines the synthesis and optimisation of a reactor‐separator‐recycle system using the geometric ideas of the attainable region technique. The approach is applied to a simple idealised system where the available process operations are limited. Because the structure being considered has been constrained, the reaction and separation sections have effectively been decoupled. It is shown that because of this decoupling the reaction and separation sections can be individually synthesised using whatever methods are available. However, the overall system must still be optimised as a whole. Three examples are considered, each with different types of objective functions.
Bifurcation Analysis of Cubic Autocatalytic Reactions: Newton Polyhedron Approach
Authors: Adesina A. A.
Published: August 2010

Autocatalytic systems constitute an important class of reactions of interest to chemists, chemical engineers and biotechnologists because they describe a variety of organic syntheses and biological reactions. However, pathological conditions such as multiple steady‐states, may arise in reactor operation due to nonlinear kinetics and reaction thermicity. In this paper, the steady‐state multiplicty and bifurcation analysis of a scheme of autocatalytic reactions (with cubic kinetic rate expressions) taking place in a non‐isothermal stirred tank has been explored For generality, the effects of both reaction stoichiometry and feed concentration of the autocatalyst have been incorporated. The solution procedure was based on the Newton polyhedron approach developed by Bailey and coworkers. When there is no inflow of the autocatalyst, one steady‐state solution exists irrespective of reaction type and kinetics. However, if the reactor is fed with less than or equal to stoichiometric ratios of the reactants, steady‐state bifurcation may occur for certain choices of system parameters. The relationship which must hold among the parameters for bifurcation to exist was established in each of the cases considered.
Modeling Ions through Conjugation Operators
Authors: Foisy M. , Fosdick S. , Wicke C. , Mavrovouniotis M. L.
Published: August 2010

In the chemical structures of ions, integer charges are nominally placed on particular atoms. But the properties of ions are affected by the dispersion of these charges to neighboring atoms. In order to account for the dispersion of charge, we propose the use of conjugation operators to model the chemical structures of ions. As a demonstration, an estimation method for the heterolytic bond dissociation energies associated with alcohol anions is derived from this type of model.
Changes in the Viscosity of Cultured Buttermilk during Commercial Filling
Authors: Butler F.
Published: August 2010

Changes in the consistency of cultured buttermilk caused by filling into cartons was investigated by comparing the viscosity of commercial buttermilk before and after filling. Two different carton filling systems were investigated. One system caused long term significant reduction in the viscosity of the buttermilk compared to samples taken directly from the storage tank. The second filling system caused no significant change in viscosity. The results demonstrate that with care and proper design of equipment, products such as buttermilk that are sensitive to shearing can be filled with minimum damage to the product.
The Production of Various Adsorbents from Lignite, and the Thermal Conductivity of the Optimum Adsorbent under Methane at Low Pressures
Authors: McCarroll S. C. , Spedding P. L. , Allen S. J.
Published: August 2010

A series of adsorbents were produced from the lignite by pyrolysis in a furnace over a range of temperatures, from 600 to 900°C, for half an hour. The lignite based granular chars were produced from its normal raw state, and also after chemical pretreatment of the chars by agitation with 1% and 2% ZnCl2 wt/wt solutions for one hour. Static Equilibrium Isotherms using methane as the adsorbate were determined at 20°C for all the samples produced, and the adsorbent with the optimum uptake determined. The actual isotherms obtained were compared against the Freundlich and Langmuir Theories. Thermal conductivity tests using the Probe Technique were carried out at 20°C on the samples again using methane as the adsorbate. The relative pressure of the methane ranged from approximately zero to 0.95. The thermal conductivity values obtained were compared and contrasted against the actual isotherms obtained at this temperature.
Numerical Simulations of Time‐Dependent, non‐Newtonian Blood Flow through Typical Human Arterial Bypass Grafts
Authors: Cole J. S. , Gillan M. A. , Raghunathan S. , O'Reilly M. J. G.
Published: August 2010

The development of the detrimental feature of intimal hyperplasia at the locations where bypass grafts are surgically attached to host arteries is believed to be promoted by haemodynamic factors. Thus, it is of interest to model the flow of blood through typical arterial bypass configurations in order to identify which features of the flow field encourage the progression of the disease.

Computational Fluid Dynamics (CFD) simulations of the non‐Newtonian flow of blood through typical three‐dimensional human femoral artery bypass graft models have been performed. The complete bypass configuration, rather than just the proximal or distal junction in isolation, has been analysed. Steady flow studies verified the strong dependence of the anastomotic flow field on the problem geometry. Flow disturbances were minimised at low anastomotic angles. A pulsatile flow computation, using a realistic femoral artery flow pulse, demonstrated noteworthy temporal and spatial variations in the flow fields at the proximal and distal anastomoses during the cardiac cycle. Due to the oscillations in direction of the flow at the distal anastomosis, and given the persistent zones of low momentum recirculating fluid, it is concluded that fluid particle residence times in the neighbourhood of the distal anastomosis are high. This feature may be of significance with regard to haemodynamic mechanisms for intimal hyperplasia.
Control of Heat Flux Profiles from Rotary Kiln Burners by Modification of Mixing
Authors: Parham J. J. , Nathan G. J. , Smart J. P. , Jenkins B. G. , Luxton R. E.
Published: August 2010

The effect of flame shaping using a Precessing Jet (PJ) burner on heat flux profiles was measured at the semi‐industrial scale (2MW) in the cement kiln zone simulator at the International Flame Research Foundation. Natural gas was used as the fuel and measurements were taken at air preheat temperatures of 400°C, 640°C and 840°C. Results showed that the radiation from the shaped PJ flames was greater than that produced by momentum controlled flames from a multi‐channel burner. Increasing the proportion of shaping jet to Precessing Jet also “stretched” the shape of the heat flux profile such that the location of the peak heat flux was shifted down the kiln and reduced in magnitude slightly. The changes in the heat flux profiles are related to the changes in the mixing field of the non‐reacting jet flows recorded using a semi‐quantitative flow visualisation technique.
The Effect of Precession on the Ignition Region in Jet Flames
Authors: Yousefpour N. , Reppel J. , Alwahabi Z. T. , Nathan G. J. , King K. D.
Published: August 2010

Planar Laser‐induced Fluorescence (PLIF) of the OH radical was used to study the base of the active combustion region in the flame produced by a mechanically precessed jet (MPJ) nozzle firing methane. Instantaneous images of the OH radical distribution were obtained for a range of jet flow rates and frequencies of jet precession about the central jet axis. The MPJ burner has been developed to better understand the effects of jet precession which have been found to reduce NOx emissions and increase emissivity in industrial flames. Broad distributions of the OH radical with widths up to 31.3 mm are shown to exist in the flame. Furthermore, combustion at the base of the flame is seen to occur not only at the periphery of the flame but also along the nozzle axis indicating the presence of a stoichiometric fuel air mixture there.
Detection and Removal of Vapour Phase Alkali Species from Hot Coal‐Derived Gases
Authors: Griffin P. G. , Campisi A. , Morrison R. J. S. , Chadwick B. L.
Published: August 2010

A high pressure, high temperature apparatus has been developed for the analysis of sorbents capable of removing alkali compounds to the concentration levels required by advanced, coal‐fired power generating systems. The reactor is capable of operating at temperatures up to 1200°C and pressures up to 2.0 MPa. A laser‐based technique ‐ photofragment fluorescence ‐ enables in‐situ analysis of the sodium content in a gas stream before and after a sorbent bed thereby determining the efficiency of the alkali removal by the various sorbents studied (typically aluminosilicate clays). The design and development of both the reactor and the laser‐based analytical technique is described.
Environmental Issues and Kiln Firing
Authors: Syred N.
Published: August 2010

It is not necessary to repeat the well known concerns about environmental issues and how they affect the design and operation of combustion processes. In this paper I wish to describe recent experiences in this area and how engineers can react to the associated issues. A UK content will be used and discussions will be made about how this relates to the global situation.
Power Generation Technologies for Low‐Rank Coals
Authors: Brockway D. J.
Published: August 2010

World electricity production is expected to double over the next twenty‐five years [1]. Dependence on fossil fuels for electricity production will continue to dominate through this period and well into the future. Currently, coal is the fuel for about 30% of total installed power generation capacity and the coal share of the electricity market is expected to remain essentially steady over the next 25 years (Figure 1). Nevertheless, the amount of coal consumed for power generation will increase substantially (Table 1) [1]. It is expected that world coal‐fired power production will grow at an average rate of 3% per annum. The forecast demand growth for power generation will require an investment of the order of US$3 trillion with about US$1 trillion in coal‐fired power generation. The increase in demand is attributed to growth in world population by 50 percent over the next 25 years [2] and by heavy demand growth in the Asia Pacific‐rim nations.

In Australia, coal is the principal fuel for power generation providing 82 percent of electricity production. Two thirds of the electricity generated from coal in Australia relies on high‐rank coals (bituminous coals) and one‐third on low‐rank coals (brown coals and lignite).

While the rate of growth of renewable energy and biomass technologies is expected to be substantial in the next few decades, it is apparent that these technologies will provide only a relatively small proportion of Australia's total energy needs. Coal will remain the principal fuel for electricity generation, in Australia and worldwide, for many decades to come.

In order to minimise the impact of coal fired power generation on the environment there is a need to develop and install advanced cycle power generation systems when it is economically viable to do so.
Mathematical Modelling of Temperature Response of Low‐rank Coal Particles During Pyrolysis
Authors: Heidenreich C. A. , Yan H. M. , Zhang D.K.
Published: August 2010

A mathematical model has been developed to predict the temperature response of dry low‐rank coal particles during pyrolysis in an inert atmosphere. The model is based on the unsteady‐state heat conduction equation in spherical coordinates and uses the Distributed Activation Energy Model to predict volatiles evolution. Measurements of the temperature response at the centre of 10mm Bowmans coal particles were conducted in a horizontal tube furnace using nitrogen as the heating medium at furnace temperatures of 150d̀C, 350d̀C, 600d̀C, 700d̀C, and 800d̀C. A sensitivity analysis was performed to assess the influence of the heat of pyrolysis and the flux of volatiles leaving the particle on the temperature response. The heat of pyrolysis can influence the predicted temperature response, however the uncertainty surrounding the magnitude and nature of its value remains a problem. The gaseous flux has no significant effect on the model predictions. Measurements of the temperature response of particles with varying moisture contents indicate that the presence of moisture significantly influences the temperature response. The effect of moisture is greater than that of the heat of pyrolysis and further work is required to incorporate moisture into the current model.
A Fundamental Study on Pyrolysis of Municipal Solid Wastes (MSW)
Authors: Jin Baosheng , Zhong Zhaoping , Zhou Shanming
Published: August 2010

This paper presents the pyrolysis experimental results of 8 component categories of Municipal Solid Wastes (MSW). Tests were carried out by a TG‐DTA 92 thermogravimetric analyzer which was made by Setaram Ltd. Co., France. This apparatus performs experiments such as TG, DTG and DTA simultaneously. MSW pyrolysis characteristics were investigated under different heating rates and different terminal temperatures. On the basis of the experimental results, kinetics parameters of MSW pyrolysis reactions were obtained and suitable kinetics model were proposed.
Safety and Chemicals
Authors: Furzer I. A.
Published: August 2010

Chemical engineers need to be aware of the increasing concern over the safe use of chemicals, a duty of care, and a positive effort to reduce exposure to chemicals by both the general public and persons working in the occupational environment. Benzene inhalation from gasoline during automobile tank filling should be minimized in order to reduce the risk of leukaemia. Dermal absorption of pesticides and solvents can have adverse health effects. Captan, an old pesticide about to re‐appear, is examined as a potential human carcinogen. Persistent old organochlorines in meat can enter the human food chain. Organophosphate pesticides, 50 times more toxic than HCN, are detected in Australian beef and sheep samples. The best estimate of occupational mortality due to past chemical exposure is 2,300 people per year. Chemical engineers need the management vision to include safety and chemicals in the design and operation of plant, and in the pathways leading to inhalation, ingestion and absorption in humans.