bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium(II) Complexes of C2‐Bridged Chiral Diphosphines: Application to Enantioselective Carbonyl‐Ene Reactions
Authors: Luo He‐Kuan , Woo Yuan‐Ling , Schumann Herbert , Jacob Chacko , van Meurs Martin , Yang Hai‐Yan , Tan Yen‐Ting
Published: May 2010

(11bR,11′bR)‐4,4′‐(1,2‐Phenylene)bis[4,5‐dihydro‐3H‐dinaphtho[2,1‐c:1′,2′‐e]phosphepin] [abbreviated as (R)‐BINAPHANE], (3R,3′R,4S,4′S,11bS,11′bS)‐4,4′‐bis(1,1‐dimethylethyl)‐4,4′,5,5′‐tetrahydro‐3,3′‐bi‐3H‐dinaphtho[2,1‐c:1′,2′‐e]phosphepin [(S)‐BINAPINE], (1S,1′S,2R,2′R)‐1,1′‐bis(1,1‐dimethylethyl)‐2,2′‐biphospholane [(S,S,R,R)‐TANGPHOS] and (2R,2′R,5R,5′R)‐1,1′‐(1,2‐phenylene)bis[2,5‐bis(1‐methylethyl)phospholane] [(R,R)‐i‐Pr‐DUPHOS] are C2‐bridged chiral diphosphines that form stable complexes with palladium(II) and platinum(II) containing a five‐membered chelate ring. The Pd(II)‐BINAPHANE catalyst displayed good to excellent enantioselectivities with ee values as high as 99.0% albeit in low yields for the carbonyl‐ene reaction between phenylglyoxal and alkenes. Its Pt(II) counterpart afforded improved yields while retaining satisfactory enantioselectivity. For the carbonyl‐ene reaction between ethyl trifluoropyruvate and alkenes, the Pd(II)‐BINAPHANE catalyst afforded both good yields and extremely high enantioselectivities with ees as high as 99.6%. A comparative study on the Pd(II) catalysts of the four C2‐bridged chiral diphosphines revealed that Pd(II)‐BINAPHANE afforded the best enantioselectivity. The ee values derived from Pd(II)‐BINAPHANE are much higher than those derived from the other three Pd(II) catalysts. A comparison of the catalyst structures shows that the Pd(II)‐BINAPHANE catalyst is the only one that has two bulky (R)‐binaphthyl groups close to the reaction site. Hence it creates a deep chiral space that can efficiently control the reaction behavior in the carbonyl‐ene reactions resulting in excellent enantioselectivity.
Measurement and simulation of flow properties of coal ash slag in coal gasification
Authors: Song Wenjia , Sun Yimin , Wu Yongqiang , Zhu Zibin , Koyama Shuntarou
Published: May 2010

The viscosities of 45 coal ash slag samples at high temperature have been measured under different temperatures and shear rates. The computer thermodynamic software package FactSage has been used to predict liquidus temperatures, volume fractions of crystallized solid particles (ϕ), and the compositions of remaining liquid phase for 45 coal ash slag samples. The flow properties of completely liquid and partly crystallized coal ash slag samples have been predicted by three viscosity models. The Urbain formalism has been modified to describe the viscosities of fully liquid slag and homogeneous remaining liquid phase in coal ash slag samples. The modified Einstein equation and Einstein–Roscoe equation have been used to describe the viscosities of heterogeneous coal ash slag samples of ϕ < 10.00 vol % and ϕ ≥ 10.00 vol %, respectively. These three models provided a good description of the experimental data of fully liquid and heterogeneous coal ash slag samples. The new models also predicted flow properties of mixtures of coal ash slags with CaO, Fe2O3, MgO, SiO2, and Al2O3. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Simulations of photodegradation of toluene and formaldehyde in a monolith reactor using computational fluid dynamics
Authors: Chong Siewhui , Wang Shaobin , Tadé Moses , Ang H. Ming , Pareek Vishnu
Published: May 2010

In this study, simulations were conducted on a monolith reactor for the photodegradation of toluene and formaldehyde. The monoliths in the reactor were treated as porous zones and the photocatalytic oxidation occurring on the monolith surfaces was modeled using Langmuir–Hinshelwood kinetics. A discrete ordinates model was used to simulate the light intensity with a novel approach, which involved an adjustable parameter—the absorption coefficient of the channel wall, for modeling the local light intensity across the porous media. The advantage of this approach was that despite its simplicity, it was able to capture and visualize the local light profile across the monolith channels and to integrate it into the reaction kinetics. Although it required a trial‐and‐error to determine the correct value of the channel wall absorption coefficient, the proposed model achieved a reasonable agreement between the simulation results and published experimental data. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Asbestosis and mesothelioma among British asbestos workers (1971–2005)
Authors: Harding Anne‐Helen , Darnton Andrew J
Published: May 2010

Background

Ascertainment of asbestosis and mesothelioma from underlying cause of death underestimates the burden of these diseases. The aims of this study were to estimate the true frequency of asbestosis and mesothelioma among asbestos workers in Great Britain (GB), and to identify factors associated with the risk of death with these diseases.

Methods

The GB Asbestos Survey was established in 1971 to monitor long‐term health outcomes among workers covered by regulations to control asbestos at work. Asbestosis and mesothelioma cases were defined by multiple cause of death, and were ascertained by identifying asbestos workers on the GB Asbestosis and Mesothelioma Registers. Standardized mortality ratios (SMRs) were calculated; the risks of asbestosis and mesothelioma were modeled with Poisson regression analysis. Deaths to the end of 2005 were included.

Results

There were 15,557 deaths between 1971 and 2005 among the 98,912 workers. Altogether 477 asbestosis and 649 mesothelioma cases were identified. The SMR for all causes was 1.42, for asbestosis 51.3, and for mesothelioma 13.5. In multiply adjusted analysis, age, sex, job, and birth cohort were significantly associated with asbestosis and mesothelioma. For asbestosis year of first exposure, and for mesothelioma latency, were also statistically significant.

Conclusions

The asbestos workers experienced high mortality from all causes, asbestosis, and mesothelioma. There was some evidence that the risk of asbestosis and mesothelioma was lower in later birth cohorts and among those first occupationally exposed to asbestos more recently. Due to the long latency of both diseases, further follow‐up is required to confirm these trends. Am. J. Ind. Med. 53:1070–1080, 2010. © 2010 Wiley‐Liss, Inc.
Exploring cultural drivers for wildlife trade via an ethnoprimatological approach: a case study of slender and slow lorises (Loris and Nycticebus) in South and Southeast Asia
Authors: Nekaris K.A.I. , Shepherd C.R. , Starr C.R. , Nijman V.
Published: May 2010

Illegal and unsustainable trade in wildlife is a major conservation challenge. For Asian primates, economic and cultural traditions, and increased forest access mean that trade may have become detrimental for certain species. Slow and slender lorises (Nycticebus and Loris) are primates particularly prevalent in trade, determined until now by focused counts of lorises in regional markets. Here, we use international trade statistics and a participant–observer approach to assess culturally specific drivers for trade in lorises in South and Southeast Asia, to provide a broader context to help mitigate this practice. Analysis of international records for the last 30 years revealed that live animal trade was more prevalent than trade in body parts (slow lorises, 86.4%; slender lorises, 91.4%), with Laos, Cambodia, and Thailand the largest exporters. We then examine drivers of international and domestic trade based on long‐term data from 1994–2009 in Sri Lanka, Cambodia, and Indonesia. We show that slender lorises are important in Sri Lankan folklore, but their use as pets and for traditional medicine is rare. Trade in Bengal slow and pygmy lorises in Cambodia for use in traditional medicines, a practice with deeply historical roots, is widespread. Despite its own set of myths about the magical and curative properties of lorises, trade in Javan, Bornean, and greater slow lorises in Indonesia is largely for pets. Conservation practices in Asia are often generalized and linked with the region's major religions and economies. We show here that, in the case of wildlife trade, culturally specific patterns are evident among different ethnic groups, even within a country. Revealing such patterns is the foundation for developing conservation management plans for each species. We suggest some participatory methods for each country that may aid in this process. Am. J. Primatol. 72:877–886, 2010. © 2010 Wiley‐Liss, Inc.
Verbrennungschemie der Biokraftstoffe: von Ethanol bis Biodiesel
Authors: Kohse‐Höinghaus Katharina , Oßwald Patrick , Cool Terrill A. , Kasper Tina , Hansen Nils , Qi Fei , Westbrook Charles K. , Westmoreland Phillip R.
Published: May 2010

Biokraftstoffe wie Bioethanol, Biobutanol und Biodiesel erfahren zunehmendes Interesse als Alternativen zu Brennstoffen auf Erdölbasis, denn sie versprechen als regenerierbare Energieträger eine langfristige und nachhaltige Perspektive mit vorteilhafter Klimabilanz. Gegenwärtige Diskussionen befassen sich mit der Produktion dieser Brennstoffe, ihrer Kompatibilität mit vorhandenen Motoren und Versorgungsstrukturen sowie der Konkurrenz zwischen der Herstellung von Biokraftstoffen und Nahrungsmitteln. Die Verbrennungschemie der Biokraftstoffe hat dagegen bisher nur wenig Aufmerksamkeit erfahren. In diesem Aufsatz beschreiben wir wesentliche Aspekte der chemischen Reaktionswege bei der Verbrennung prototypischer Vertreter potenzieller Biokraftstoffe wie Alkohole, Ether und Ester. Im Vordergrund stehen dabei die Zersetzungs‐ und Oxidationsmechanismen sowie mögliche unerwünschte Emissionen. Neue experimentelle Methoden und Modellstudien erlauben detaillierte Einblicke in die hochkomplexen Netzwerke chemischer Reaktionen bei der Verbrennung von Biokraftstoffen. Die Chemie dieser Prozesse zu verstehen ist eine wichtige Voraussetzung für die verantwortungsbewusste Auswahl alternativer Kraftstoffe der nächsten Generation.
Ultraschnelle Schwingungsdynamik und lokale Wechselwirkungen in hydratisierter DNA
Authors: Szyc Łukasz , Yang Ming , Nibbering Erik T. J. , Elsaesser Thomas
Published: May 2010

Biochemische Prozesse laufen überwiegend in wässriger Umgebung ab. Eine Schlüsselrolle für Struktur und Funktion von Biomolekülen spielt dabei die Wechselwirkung mit Wassermolekülen. Desoxyribonukleinsäure (DNA), der grundlegende Träger genetischer Information, liegt im Gleichgewicht in einer Doppelhelixstruktur vor, die durch zwischenmolekulare Wasserstoffbrücken in Basenpaaren zusammengehalten und durch eine Umgebung von Wassermolekülen mit fluktuierenden Wasserstoffbrücken hydratisiert wird. Elementare Schwingungsbewegungen hydratisierter DNA und die schnellsten Veränderungen der DNA‐Wasser‐Wechselwirkung und der Hydratisierungsgeometrien treten im Zeitbereich unterhalb 1 ps auf. Methoden der nichtlinearen Ultrakurzzeit‐Schwingungsspektroskopie bieten Zugang zu diesen Prozessen, indem die Schwingungsdynamik von DNA und Wasser zeitaufgelöst verfolgt wird. Derartige Untersuchungen führen zu einem detaillierten Verständnis von DNA‐Schwingungen und ihrer Dynamik und geben Einblick in die Nichtgleichgewichtseigenschaften und ‐strukturen hydratisierter DNA.
Ultrafast Vibrational Dynamics and Local Interactions of Hydrated DNA
Authors: Szyc Łukasz , Yang Ming , Nibbering Erik T. J. , Elsaesser Thomas
Published: May 2010

Biochemical processes occur mainly in aqueous environments, where interactions with water molecules play a key role for both the structure and function of biomolecules. Deoxyribonucleic acid (DNA), the basic carrier of genetic information, is characterized by an equilibrium double helix structure which is held together by intermolecular hydrogen bonds between base pairs and hydrated by an environment of water molecules with fluctuating hydrogen bonds. Basic vibrational motions of hydrated DNA and the fastest changes in the DNA–water interactions and hydration geometries occur in less than 1 ps. These processes can be accessed by mapping the vibrational dynamics of DNA and water in a time‐resolved way by nonlinear ultrafast vibrational spectroscopy. Recent studies provide a detailed understanding of DNA vibrations and their dynamics, and give insight into nonequilibrium properties and structures of hydrated DNA.
A Lattice Boltzmann approach for predicting the capture efficiency of random fibrous media
Authors: Rebaï Mehdi , Drolet François , Vidal David , Vadeiko Ilya , Bertrand François
Published: May 2010

We study the propagation of submicron airborne particles through random fibre networks such as paper. In our approach, we first construct a three‐dimensional model of the network and then use a Lattice Boltzmann method to obtain the flow of air through that structure. We finally calculate the trajectories of airborne particles and determine the fraction of these particles that impinge on fibres in the network. The combined approach is used to obtain pressure drop and mechanical filtration efficiency curves for a variety of structures. Our results show that, at fixed pressure drop and flow rate, a filter with a high basis weight and porosity will perform better than one made from fewer fibres that are more densely packed, at least in the range of porosities considered. For filters with a bimodal fibre size distribution, we find that the minimum in the efficiency curve becomes sharper and moves to smaller particle sizes as the mean fibre diameter of the mixture decreases, as expected from single‐fibre theory. The efficiency of capture by diffusion and interception exhibits a weaker dependence on surface area mean fibre diameter than that predicted by theory, in agreement with the observations of Brown and Thorpe. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
A quantitative method for fungal ligninolytic enzyme screening studies
Authors: Ang Teck Nam , Ngoh Gek Cheng , Chua Adeline Seak May
Published: May 2010

Screening is conducted to select a fungus with desired characteristics intended for various applications, e.g. bioremediation and enzyme production. A qualitative method was used in this study for screening of fungal ligninolytic enzyme activities. The fungal ligninolytic activity was correlated with its growth from the screenings to identify a suitable fungus for solid substrate fermentation. Four strains of fungi, namely, Phanerochaete chrysosporium, Pycnoporus sanguineus, Phlebia radiata and Pleurotus sajor‐caju, were screened for their ligninolytic enzyme activities using guaiacol and remazol brilliant blue‐R (RBB‐R) as screening reagents. The screenings were conducted at both, the optimal growth temperature of each fungus and 35 °C. All the fungi, except P. radiata, showed positive guaiacol oxidation and RBB‐R decolourisation activities. On the basis of the results, P. sajor‐caju may be a suitable fungus for use in bioconversion of lignocellulose because it maintained guaiacol oxidation and RBB‐R decolourisation activities at 35 °C. Its halo‐to‐colony area ratios of guaiacol oxidation and RBB‐R decolourisation after 6 days were 7.0 and 2.7, respectively. In the subsequent growth study, the measured colony area was closely correlated with the dry fungal cell weight with a regression value (R2) of 0.971. Thus, the colony size could be used as an indicator of fungal growth if the screening media do not significantly slow the growth of fungus. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
The seventeen theoretical constructs of information searching and information retrieval
Authors: Jansen Bernard J. , Rieh Soo Young
Published: May 2010

In this article, we identify, compare, and contrast theoretical constructs for the fields of information searching and information retrieval to emphasize the uniqueness of and synergy between the fields. Theoretical constructs are the foundational elements that underpin a field's core theories, models, assumptions, methodologies, and evaluation metrics. We provide a framework to compare and contrast the theoretical constructs in the fields of information searching and information retrieval usingintellectual perspectiveandtheoretical orientation. The intellectual perspectives areinformation searching,information retrieval, andcross‐cutting; and the theoretical orientations areinformation,people, andtechnology. Using this framework, we identify 17 significant constructs in these fields contrasting the differences and comparing the similarities. We discuss the impact of the interplay among these constructs for moving research forward within both fields. Although there is tension between the fields due to contradictory constructs, an examination shows a trend toward convergence. We discuss the implications for future research within the information searching and information retrieval fields.
Stabilization and SDG condition of serially connected vibrating strings system with discontinuous displacement
Authors: Han Zhong‐Jie , Xu Gen‐Qi
Published: May 2010

Based on joint feedback controls, the stabilization issue of a serially connected vibrating strings system is presented. Suppose that the two ends of the strings system are clamped and the vertical force of strings is continuous at interior nodes while the transversal displacement is discontinuous. The vertical force of strings at interior nodes are observed and the compensators are derived from the observation values. Then the feedback controllers are arranged at interior nodes to stabilize this system. Through a detailed spectral analysis, this closed loop system is proved to be asymptotically stable and there exists a sequence of (generalized) eigenvectors of the system that forms a Riesz basis with parentheses for the state space under certain conditions. Hence the spectrum‐determined‐growth (SDG) condition holds. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Extraction of monoclonal antibodies (IgG1) using anionic and anionic/nonionic reverse micelles
Authors: George Daliya A. , Stuckey David C.
Published: May 2010

Purification schemes for antibody production based on affinity chromatography are trying to keep pace with increases in cell culture expression levels and many current research initiatives are focused on finding alternatives to chromatography for the purification of Monoclonal antibodies (MAbs). In this article, we have investigated an alternative separation technique based on liquid–liquid extraction called the reverse micellar extraction. We extracted MAb (IgG1) using reverse micelles of an anionic surfactant, sodium bis 2‐ethyl‐hexyl sulfosuccinate (AOT) and a combination of anionic (AOT) and nonionic surfactants (Brij‐30, Tween‐85, Span‐85) using isooctane as the solvent system. The extraction efficiency of IgG1 was studied by varying parameters, such as pH of the aqueous phase, cation concentration, and type and surfactant concentration. Using the AOT/Isooctane reverse micellar system, we could achieve good overall extraction of IgG1 (between 80 and 90%), but only 30% of the bioactivity of IgG1 could be recovered at the end of the extraction by using its binding to affinity chromatography columns as a surrogate measure of activity. As anionic surfactants were suspected as being one of the reasons for the reduced activity, we decided to combine a nonionic surfactant with an anionic surfactant and then study its effect on the extraction efficiency and bioactivity. The best results were obtained using an AOT/Brij‐30/Isooctane reverse micellar system, which gave an overall extraction above 90 and 59% overall activity recovery. An AOT/Tween‐85/Isooctane reverse micellar system gave an overall extraction of between 75 and 80% and overall activity recovery of around 40–45%. The results showed that the activity recovery of IgG1 can be significantly enhanced using different surfactant combination systems, and if the recovery of IgG1 can be further enhanced, the technique shows considerable promise for the downstream purification of MAbs. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Synthesis and application of a novel single‐isomer mono‐6‐deoxy‐6‐((2S,3S)‐(+)‐2,3‐O‐isopropylidene‐1,4‐tetramethylenediamine)‐β‐cyclodextrin as chiral selector in capillary electrophoresis
Authors: Liu Peng , He Wei , Qin Xiang‐Yang , Sun Xiao‐Li , Chen Hui , Zhang Sheng‐Yong
Published: May 2010

A novel single isomer of positively charged β‐cyclodextrin, mono‐6‐deoxy‐6‐((2S,3S)‐(+)‐2,3‐O‐isopropylidene‐1,4‐tetramethylenediamine)‐β‐CD (MIPTACD) was designed and synthesized in seven steps starting from commercially available (2R,3R)‐tartaric acid. The chiral resolution abilities of the new cationic chiral selector were studied by capillary electrophoresis using 10 different dansyl (Dns)‐amino acids and N‐acetylphenylalanine (N‐Ac‐Phe) as model analytes. The effects of running buffer pH and chiral selector concentration on the separation selectivity, resolutions, and migration times of analytes were studied in detail. MIPTACD shows a very good chiral recognition ability even at very low concentrations at the investigated pH values, as shown by the very large values of selectivity and resolution towards amino acids enantiomers to be assessed. Chirality, 2010. © 2010 Wiley‐Liss, Inc.
Supercritical fluid chromatography and steady‐state recycling: Phase appropriate technologies for the resolutions of pharmaceutical intermediates in the early drug development stage
Authors: Yan Tony Q. , Orihuela Carlos , Preston Jay P. , Xia Fang
Published: May 2010

The use of phase appropriate technologies is critical for efficiently moving drug candidates forward in the early stages of drug discovery and development. Phase appropriate purification technology develops the analytical method and subsequently scales up the method and turns the sample around quickly (Kennedy et al., J Chromatogr A 2004; 1046:55). In this article, separation results and conditions from supercritical fluid chromatography (SFC), high‐performance liquid chromatography (HPLC), and steady‐state recycling (SSR) for the resolutions of three pharmaceutical intermediates in the early stage of the drug development are discussed. The first study used SFC and SSR to separate an impurity for a Good Manufacturing Practice (GMP) campaign. The analytical method development and scale‐up conditions are discussed. Productivity, solvent usage, and sample solubility under SFC and SSR conditions are also compared. The second study compared SFC to batch HPLC in separating a diastereomer. Due to higher separation efficiency, SFC was able to resolute multiple peaks. The third study involved the addition of dichloromethane as a co‐solvent in SFC purification—improving sample selectivity and solubility. From the separation results of these purifications, SFC and SSR are clearly phase appropriate technologies in the early drug development stage. Chirality, 2010. © 2010 Wiley‐Liss, Inc.
Toward a generalization of the Clough‐Lutz‐Jirgensons effect: Chiral organic acids with alkyl, hydroxyl, and halogen substituents
Authors: Nitsch‐Velasquez Lucia , Autschbach Jochen
Published: May 2010

The optical rotation of natural amino acids becomes more positive when the medium is changed from approximately neutral to strongly acidic (Clough–Lutz–Jirgensons (CLJ) effect). In this work, it is shown by time–dependent density functional computations that the effect can be generalized to other α–substituted chiral carboxylic acids. The physical origin of the generalized CLJ effect is similar to that in amino acids, linking the absolute configuration directly to the sign of CLJ. For conformationally flexible molecules with small magnitudes of the optical rotation, the presence of a CLJ effect might aid the assignment of absolute configurations based on comparing experimental data with computed chiroptical responses. Chirality, 2010. © 2010 Wiley‐Liss, Inc.
Mesoporöse Pt/SBA‐15‐Katalysatoren für die enantioselektive Flüssigphasenhydrierung von Ethylpyruvat
Authors: Böttcher S. , Hoffmann C. , Räuchle K. , Reschetilowski W.
Published: May 2010

Die enantioselektive Hydrierung von Ethylpyruvat wurde in Gegenwart der geordneten, mesoporösen Materialien SBA‐15 und Al‐SBA‐15 als Träger chiral‐modifizierten Platins durchgeführt. Dabei wurde der Einfluss der Oberflächenacidität der oxidischen Träger auf die Reaktion untersucht. Mit Zunahme der Gesamtacidität konnte eine Steigerung der Enantioselektivität beobachtet werden. An optimierten Katalysatorsystemen konnte (R)‐Ethyllactat mit Enantioselektivitäten von 90 – 94 %ee bei vollständigem Umsatz hergestellt werden.
Structure–process–yield interrelations in nanocrystalline cellulose extraction
Authors: Hamad Wadood Y. , Hu Thomas Q.
Published: May 2010

In order to improve the extraction of nanocrystalline cellulose (NCC) from sulfuric acid hydrolysis of chemical pulps, we have studied the effect of hydrolysis conditions on the degree of polymerization (DP), the extent of sulfation, morphological, and solid‐state characteristics of the extracted materials vis‐à‐vis yield.

Our results demonstrate that sulfation plays a significant role in (i) determining the yield of, and (ii) imparting the unique solid‐state characteristics to, the extracted, H2O‐insoluble cellulose nanomaterial from sulfuric acid hydrolysis. The hydrolysis process is itself proven to be highly reproducible, and NCC with high crystallinity (>80%) and a yield between 21% and 38% could be extracted from a fully bleached, commercial softwood kraft pulp using 64 wt.% sulfuric acid at 45–65°C after freeze drying. The NCC aggregates, with iridescent patterns typical of chiral nematic materials, are parallelepiped rod‐like structures which possess cross‐sections in the nanometer range and lengths orders of magnitude larger, resulting in high aspect ratios.

The Ruland–Rietveld analysis was employed to precisely resolve X‐ray diffraction patterns and obtain information on crystallite size, crystalline and amorphous areas, and crystallinity of the extracted materials.
Wet scrubbing intensification applied to hydrogen sulphide removal in waste water treatment plant
Authors: Biard Pierre‐François , Couvert Annabelle , Renner Christophe , Levasseur Jean‐Pierre
Published: May 2010

Hydrogen sulphide removal in a waste water treatment plant at semi‐industrial scale in a compact wet scrubber has been investigated. The gas residence time in the scrubber was reduced to 30 ms using a NaOCl caustic scrubbing solution. The contactor is composed of a wire mesh packing structure where liquid and gas flow co‐currently at high velocity (>12 m s−1). H2S removal percentages higher than 95% could be achieved whereas a moderate pressure drop was measured (<4000 Pa). Both the hydrodynamic and chemical conditions can influence the efficiency of the process. Correlations were developed to predict both the pressure drop and the H2S removal efficiency at given operating conditions.
A novel three‐phase airlift reactor without circulation of solids
Authors: Olivieri Giuseppe , Marzocchella Antonio , Salatino Piero
Published: May 2010

A novel configuration of a three‐phase internal loop airlift reactor is proposed. The draft is divided in two sections: (top) gas–liquid contact section; (bottom) liquid–solid contact section. Solids particles are fluidized in the bottom section by liquid circulation. The main advantage compared with classic airlift or three‐phase fluidized bed is the reduced stress on particles as interference with bubbles is prevented. Experiments with silica sand (325 µm diameter) were carried out to characterise the hydrodynamics of the airlift. The influence of superficial gas velocity, overall solids hold‐up and sparger height were assessed. A theoretical analysis was proposed to derive simple design criteria.
Advanced measurement techniques for GLS reactors
Authors: Mudde R. F.
Published: May 2010

A review of advanced measurement techniques in gas–liquid–solid systems is presented. Most GLS systems are operated at relatively high volume fractions. This makes the systems opaque and less suited for investigations based on laser application. Several measuring techniques have been developed to deal with non‐transparent systems. Amongst these are Electrical Capacitance Tomography, X‐ray CT scanning and Magnetic Resonance Imaging. This contribution discusses some of the recent development and identifies the directions research is taking.
Numerical simulation of liquid spray dispersion in a fluidized bed
Authors: Pougatch Konstantin , Salcudean Martha
Published: May 2010

A numerical model that simulates liquid spray dispersion in the fluidized bed of solid particles is presented. The model includes flow through the atomization device (nozzle), phase inversion and formation of the spray, its interaction with the solid particles, and liquid propagation within the bed. All these processes are modelled simultaneously to reflect the couplings existing between them. The model utilises a Eulerian description for all three phases to allow for the continuous computations throughout the whole domain. The comparison with experimental data reveals reasonably good agreement between the predicted and measured liquid to solid mass ratio distributions.
Dynamical mass‐transfer process of a CO2 bubble measured by using LIF/HPTS visualisation and photoelectric probing
Authors: Hanyu Kodai , Saito Takayuki
Published: May 2010

We directly visualised the dynamical mass‐transfer process from a zigzagging rising CO2 bubble (2.9 mm in equivalent diameter) to its surrounding liquid by using laser‐induced fluorescence/8‐hydroxypyrene‐1, 3, 6‐trisulfonic acid (LIF/HPTS). We measured the surrounding liquid motion induced by bubble buoyancy using particle image velocimetry (PIV). Further, the CO2 concentration profile inside the bubble wake was measured directly by using a newly developed photoelectric optical fibre probe (POFP). Making the best and mutually complementary use of these three measurement techniques, we discuss the relationship between the mass‐transfer process and the flow structure. We succeeded in clearly visualising CO2‐rich regions corresponding with the dynamical mass‐transfer process from the bubble to the wake and the surrounding liquid (LIF/HPTS). We also obtained a CO2 concentration profile in the bubble wake (the POFP). It was found that the CO2‐rich regions were formed into horseshoe‐like vortices; the CO2 concentration at the centre region of the wake was the highest, and the concentration decreased toward the outer edge of the wake; the CO2‐rich regions were transported widely into the surrounding liquid by the advective liquid‐phase flows (PIV). In addition, we discuss the performance and characteristics of the newly developed POFP.
Integrated process for hydrophobic VOC treatment—solvent choice
Authors: Darracq G. , Couvert A. , Couriol C. , Amrane A. , Le Cloirec P.
Published: May 2010

A process coupling absorption of a gaseous pollutant in an organic phase and biodegradation was considered to treat hydrophobic volatile organic compounds (VOC). The purpose of this work was to choose the best solvent for the absorption of some VOC (dimethylsulfide, dimethyldisulfide, and toluene) and to examine solvent biodegradability as well as VOC biodegradation by activated sludge. Some experiments were carried out on some selected solvents leading to select di‐2‐ethylhexyl‐adipate (DEHA) and poly‐di‐methyl‐siloxane (PDMS) for their high absorption capacity. Biodegradation experiments showed that toluene and DMDS can be removed in solvent on water emulsions, while DMS removal by biodegradation remains to confirm owing to its high volatility. However, experiments showed DEHA biodegradation, contrarily to PDMS which was therefore selected for subsequent experiments.
Laboratory investigation of inversion of heavy oil emulsions
Authors: Gillies Randall G. , Sun Ruijun , Shook Clifton A.
Published: May 2010

Laboratory investigations have been undertaken to assess the suitability of heavy oil‐in water emulsions for pipeline transportation. The emulsions contained 65% oil in water and were prepared using polyethoxy nonylphenol surfactants. Two methods were employed for simulating the shear process which accompanies pipeline flow: a bench scale stirred vessel and a rotated pipe toroid. The progress of the emulsions towards inversion, at which point the oil becomes the continuous phase, was followed by measuring the surfactant concentration in the aqueous phase using liquid chromatography. At inversion the surfactant concentration falls below the threshold level required to sustain an oil‐in‐water emulsion. The experiments showed that the lifetime of the emulsion depends upon the initial surfactant dosage, the solids content of the oil, the intensity of shear and the nature of the shear process. Laminar flow was found to be less desirable than turbulent flow.
Submarine mine tailings management
Authors: Stronach James A. , Robert S. , Gardiner M. , Zhang Yuangao , Schriek Willem S.
Published: May 2010

The placement of mine tailings at depth in the marine environment is reviewed. This review considers first the engineering aspects of a pipeline system which transports tailings slurry from a process plant to the coast and then to a location at a depth of typically 200 m on the continental slope. Next, the fluid dynamic behaviour of the tailings, once discharged from the end of the pipe, are discussed, and a numerical model is presented which simulates the fate of both the dissolved and solids component of the tailings slurry in the marine environment. This latter model can be used to estimate the environmental impact of a proposed deep sea tailings placement system.
Electrochemical mass transfer measurements in a Y‐bifurcation model
Authors: Mahinpey Nader , Ojha Matadial , Johnston K. Wayne , Trass Olev
Published: May 2010

A novel technique was used to fabricate nickel flow models of a straight pipe and a Y‐bifurcation. These were used to obtain integral mass transfer coefficients by the electrochemical technique. For the straight pipe, good agreement was obtained with previously reported mass transfer correlations. The use of an upstream anode in addition to the downstream anode led to higher mass transfer at the cathode with laminar flow because of the additional near‐wall ions produced by the upstream anode. With increasing Schmidt number, the effect of transition from laminar to turbulent flow on mass transfer was delayed to progressively higher Reynolds numbers because of the reduced mass transfer boundary layer thickness relative to the viscous sublayer. With the Y‐bifurcation, possible flow separation and the formation of a new mass transfer boundary layer in the daughter branches significantly influence the mass transfer behaviour.
A simple synthesis method for studying thermally integrated distillation sequences
Authors: Sobočan Gorazd , Glavič Peter
Published: May 2010

In this paper an improved method for studying processes for separation of multicomponent mixtures is presented. A thermodynamically oriented procedure was developed for the analysis and synthesis of the best heat‐integrated distillation system. Systematic ranking of possible schemes was used in order to verify the best structure of a heat‐integrated distillation system. An integrability criterion was introduced for the selection of the most promising heat‐integrated sequences. Distillation columns were studied according to their ability for heat integration. The proposed selection of possible distillation columns sequences using rising integrability criteria gave a good approximation of the best heat‐integrated distillation column sequences according to their total annual cost. Computational simulation of the process and pinch analysis were used for thermodynamic optimization of energy consumption. The method is illustrated with five‐ and six‐component example problems.
Removal of lead, cadmium and zinc from aqueous solutions by precipitation with sodium Di‐(n‐octyl) phosphinate
Authors: Esalah Jamaleddin O. , Weber Martin E. , Vera Juan H.
Published: May 2010

Sodium di‐(n‐octyl) phosphinate (NaL) was used as a precipitating agent to remove heavy metals from aqueous nitrate solutions. Cadmium, zinc and mixtures of lead, cadmium and zinc were precipitated in the form of PbL2(s), CdL2(s), and ZnL2(s). Lowering the pH of the feed solution reduced the removal of the metals as some of the phosphinate precipitated in the acid form as HL(S). The removal of lead, cadmium, and zinc, from a solution containing the three metals gave a selectivity in the order Zn > Pb > Cd. Predictions of an equilibrium‐constant model, using measured solubility products of the precipitates and literature values of stability constants, gave metal removals, loss of precipitating agent, and equilibrium pH in good agreement with measured values.
Etude numérique de l'évaporation dans un courant d'air humide laminaire et turbulent d'un film d'eau ruisselant sur une plaque inclinée
Authors: Mezaache El Hacene , Daguenet Michel
Published: May 2010

En utilisant, pour le film, des équations de transfert unidimensionnelles, partiellement bidimensionnelles et bidimensionnelles, les auteurs déterminent le modéle qu'il convient d'adopter selon les conditions thermiques imposées à la parol. lls comparent leurs résultats à ceux d'autres travaux et étudient l'influence du débit massique du film liquide et de l'inclinaison. Its montrent que le transfert de chaleur est dominé par le transfert lié à la transition liquide‐vapeur et que la contribution de la chaleur sensible n'est significative qu'au niveau de la région turbulente oú la température et la densité du flux de vapeur sont quasi constantes et l'épaisseur du film liquide uniforme. Le débit et l'inclinaison sont sans influence sur les transferts lorsque la paroi est adiabatique. Pour une parol isotherme ou à densite de flux de chaleur imposée, le débit influence essentiellement la région turbulente en réduisant la température de l'interface et les coefficients de transferts de chaleur et de masse. L'inclinaison affecte principalement la région laminaire; elle accroit la vitesse d'écoulement du film, réduit son épaisseur et agit peu sur les coefficients de transfert.
A low reynolds number k‐ϵ modelling of turbulent pipe flow: Flow pattern and energy balance
Authors: Thakre Shirish S. , Joshi Jyeshtharaj B.
Published: May 2010

The present paper addresses a comparative analysis of twelve different versions of low Reynolds number k‐ϵ turbulence models. The predictive capability of the models have been tested on the basis of the flow patterns and energy balance. Numerical simulations were performed at the Reynolds numbers of 7400, 22 000 and 500 000. The predicted mean axial velocity and turbulent kinetic energy were compared with the experimental data of Durst et al. (1995) and Schildknecht et al.(1979) for the Reynolds number of 7400 and 22000 respectively. The overall energy balance was established at three Reynolds numbers of 7400, 22 000 and 500000. A comparison of all the models has been predicted.
The solubility of SO3 and sulfuric acid in acetone and MEK
Authors: Won Wooyoung , Hudgins Robert R. , Lohi Ali , Silveston Peter L.
Published: May 2010

Solubility experiments undertaken between 18°C and 24°C showed that solubility of SO3 in either acetone or methyl ethyl ketone (MEK) is very small. On the other hand, with these solvents sulfuric acid is fully miscible up to a volume ratio of 30:200 acid:solvent.
The influence of pH upon the hydrolysis of carboxymethylcellulose with cellulases from Trichoderma reesei
Authors: Rodríguez V. Bravo , Dueñas M. P. Páez , Requena A. Reyes , El‐Hadj M. Aoulad , López A. I. García
Published: May 2010

We have studied the enzymatic hydrolysis of carboxymethylcellulose (CMC) with Celluclast, a commercial preparation of cellulases deriving from Trichoderma reesei, by monitoring the variation in the concentrations of glucose and reducing sugars at a constant temperature of 50°C and different pH values. We determined both glucose and overall yield, concluding that the production of glucose directly by endoglucanase is higher than that coming from the hydrolysis of cellobiose by β‐1,4‐glucosidase and that the rate at which cellobiose is formed can be calculated via kinetic parameters that are due in the end mainly to exoglucanase activity. We observed the effect of pH upon the kinetic parameters and found that the ideal value for the hydrolysis of CMC is one of pH 4.9.
A review of techniques for instrumentation design and upgrade in process plants
Authors: Bagajewicz Miguel
Published: May 2010

This article is a review of the area of optimal instrumentation location in process plants for both grassroots designs and upgrades. Emphasis is put in methods for monitoring purposes and based on the cost minimization model. These methods are mostly related to data reconciliation paradigms and include especial consideration to the detection of gross errors. Connections between this model and other models based on other objective functions and goals are analyzed. Finally, the emerging field of sensor design for efficient process fault detection is briefly covered.
A simple and effective model for cross‐flow microfiltration and ultrafiltration
Authors: Makardij Anais (Alice) A. , Farid Mohammed M. , Chen Xiao Dong
Published: May 2010

A semi‐theoretical unsteady‐state model for the flux in cross‐flow microfiltration and ultrafiltration has been developed. The model predicts fouling behaviour for a wide range of particle sizes and foulant concentrations. The developed model uses only two coefficients, k1 and k2, incorporating both the influences of the cake formation and the shear cleaning of the membrane, to describe flux decline. These two parameters were found to be almost independent of the operating conditions. The model provides both a fundamental understanding of the key physical phenomena governing flux decline and a rational basis for the design of an improved and modified cross flow filters.
Axial distribution of solids holdup for both hydrophilic and hydrophobic particles in three‐phase fluidized beds
Authors: Zhang Ji‐Yu , Lin Cheng , Lin Chun‐Shen
Published: May 2010

The axial concentration distribution of the hydrophilic and hydrophobic particles, corresponding to poor and good attachment to rising bubbles in water, was investigated in a gas‐liquid‐solid fluidized bed. The sedimentation‐dispersion model depicted satisfactorily the axial distribution of solids holdup by modifying only the terminal settling velocity, which considered the effect of an additional drag force resulting from the attached rising bubbles. This model explained correctly the different phenomena, i.e. solids holdup decreased with increasing the axial height in the non‐attached system, but increased in the attached system.
Prediction of gas hold‐up in a bubble column filled with pure and binary liquids
Authors: Syeda Sultana R. , Afacan Artin , Chuang Karl T.
Published: May 2010

A dimensionless correlation for gas hold‐up in a bubble column filled with pure liquids and binary mixtures has been developed. The criteria of bubble coalescence in pure liquids and foamability of binary mixtures have been included successfully in the proposed correlation. For the first time, comprehensive data of gas hold‐up with respect to concentration in four binary systems are presented. The often‐reported enhancement of gas hold‐up in aqueous alcohol mixtures has been observed experimentally. The proposed correlation is able to predict successfully the trend of gas hold‐up enhancement with respect to concentration. The estimated values are found to be within 7% of the measured values.
Kinetics of the photocatalytic total oxidation of different alkanes and alkenes on TiO2 powder
Authors: Kleinschmidt Olaf , Hesse Diethard
Published: May 2010

Although photocatalyzed total oxidation reaction of hydrocarbon species has been discussed in the literature, most of these studies were performed to obtain an appropriate reaction mechanism. Studies on the kinetics of this type of reaction are rare. Using titanium dioxide as the photo catalyst, the kinetics of the total oxidation of methane, ethane, ethene, as well as propene, have been investigated using a continuous‐stirred tank reactor. In the experiments, the hydrocarbon concentrations, the oxygen concentration, and the irradiation intensity were varied. The results obtained are evaluated on the basis of a kinetic model to derive rate equations which can be used for reactor design.
Analysis of flux decline during ultrafiltration of sugarcane juice (Limed) using cross flow cell
Authors: Gopal Uppaluri V. S. Rama , Verma Nishith , Bhattacharya Prashant K.
Published: May 2010

Experimental and theoretical studies were carried out to analyse the flux decline behaviour of limed sugarcane juice and retention characteristics of its components (total dissolved solids, sucrose and colour) in a rectangular cross flow ultrafiltration cell. Retentions of sucrose and total dissolved solids were found to increase with increase in pressure and feed bulk concentration. A theoretical model was developed to describe flux decline, combining the effects of formation of a gel‐like porous layer (constituting high molecular weight substances) and osmotic pressure controlled layer (constituting low molecular weight substances). Predictions were observed to be in good agreement.
An apparatus for the measurement of surface tensions at high pressures and temperatures
Authors: Millette Jacques P. , Scott Donald S. , Reilly Irvine G. , Majerski Piotr , Piskorz Jan , Radlein Desmond , Debruijn Theo J. W.
Published: May 2010

An apparatus for the measurement of surface tensions of organic liquids in contact with a gas has been developed which is capable of operation to 400°C and to 14 MPa. It is based on the maximum bubble pressure technique, modified for hydrocarbon oils at high pressures and temperatures. Accuracy of measurement is of the order of ±3% for non‐aqueous systems for values down to 5 mN/m. Only a 20 to 30 mL liquid sample is required, and small gas volumes. In practice, it was found that measurements with most organic liquids could only be made to a maximum of about 350°C because of the thermal instability of most of these compounds, in particular, for hydrocarbon liquids. Any thermal decomposition or coke deposition leads to inaccurate results. Results obtained for known liquids are compared with values given in the literature.
Gas hold‐up in stirred tank reactors
Authors: Yawalkar Archis A. , Pangarkar Vishwas G. , Beenackers Anthony A. C. M.
Published: May 2010

Based on a study of the gas hold‐up data for stirred tank reactor generated in the present work and the data available in the literature for large stirred tank reactors (T = 0.57 m to 2.7 m) equipped with disc turbines and pitched blade downflow turbines a correlation is presented which reliably predicts gas hold‐up data over wide range of system configurations and operating parameters. The parameter used, N/Ncd, relates gas hold‐up at impeller speed N with respect to the gas hold‐up at minimum impeller speed for complete dispersion of the gas, Ncd. It is shown that the gas hold‐up data of different workers when compared on the basis of N/Ncd, shows unanimity.
Bubble characteristics of a scaled‐down three‐phase fluidized bed
Authors: Safoniuk Mike , Grace John R. , Lim Kok‐Seng
Published: May 2010

Experiments were carried out in a 0.29 m diameter column to provide information on bubble characteristics relevant to an industrial three‐phase fluidized bed reactor. Using a specially built electrical conductivity probe, together with a series of computer programs to gather and filter the data, local bubble properties (rise velocities, pierced chord lengths, frequencies, and direction of travel) were measured. The data are compared to existing correlations. Since the operating conditions were within the dispersed bubble regime, uniform bubbling was anticipated. However, the actual system indicated considerable non‐uniformity, with individual bubbles, large swarms of bubbles and particles traveling at all angles. As a result, it is shown that bubble rise velocities are not necessarily a good measure of the bubble properties and must be vectorized to provide a good means of estimating gas hold‐up.