bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of subclinical inflammatory airway disease on equine respiratory function evaluated by impulse oscillometry
Authors: RICHARD E. A. , FORTIER G. D. , DENOIX J.‐M. , ART T. , LEKEUX P. M. , ERCK E. van
Published: March 2009

Reasons for performing study: Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously been described using either forced expiration or forced oscillations techniques. However, sedation or drug‐induced bronchoconstriction were usually required. The impulse oscillometry system (IOS) is a noninvasive and sensitive respiratory function test validated in horses, which could be useful to evaluate IAD‐affected horses without further procedures.

Objectives: To determine the sensitivity of IOS in detecting alterations of the respiratory function in subclinically IAD‐affected horses without inducing bronchoprovocation and to characterise their respiratory impedance according to frequency for each respiratory phase.

Methods: Pulmonary function was evaluated at rest by IOS in 34 Standardbred trotters. According to the cytology of bronchoalveolar lavage fluid (BALF), 19 horses were defined as IAD‐affected and 15 horses were used as control (CTL). Total respiratory resistance (Rrs) and reactance (Xrs) from 1–20 Hz as well as their inspiratory and expiratory components were compared between groups.

Results: A significant increase of Rrs at the lower frequencies (R1–10 Hz) as well as a significant decrease of Xrs beyond 5 Hz (X5–20 Hz) was observed in IAD compared to CTL horses. IOS‐data was also significantly different between inspiration and expiration in IAD‐affected horses. In the whole population, both BALF eosinophil and mast cell counts were significantly correlated with IOS measurements.

Conclusions: Functional respiratory impairment may be measured, even in the absence of clinical signs of disease. In IAD‐affected horses, the different parameters of respiratory function (Rrs or Xrs) may vary depending on the inflammatory cell profiles represented in BALF.

Potential relevance: Impulse oscillometry could be used in a routine clinical setting as a noninvasive method for early detection of subclinical respiratory disease and of the results of treatment in horses.
Middlebrowing the Avant-Garde: Equus on the West End
Authors: Claycomb Ryan M.
Published: March 2009

As text, performance, and pop-culture signifier, we can trace Peter Shaffer's play Equus – from its avant-garde influences through its middle-class anxieties to the middlebrow spectacle of the recent high-profile production in London – as a local example of a familiar (but not inevitable) narrative of the dilution and recuperation of avant-garde aesthetics by a late-capitalist economic system of transnational media integration and commodification. The play itself, from its original production onward, pathologizes and contains the avant-garde as both mad and queer, recuperating it into a framework of liberal, middle-class ethics and economics, an effort that is redoubled by this most recent production in text, in performance, and in the material context of the performance. But even as this play, in performance, seems to help mark out the trajectory of the death of the avant-garde, it also troubles the waters of this death-narrative with traces of the residuum of a resistant, even queered, avant-garde that lingers beyond narrative containment and cultural co-opting.
Numerical modeling of an avalanche impact against an obstacle with account of snow compressibility
Authors: Kulibaba V.S. , Eglit M.E.
Published: March 2009

The numerical solution to a time-dependent two-dimensional problem of an avalanche impact against a wall is presented. The height of the wall is much larger than the flow depth. Compressibility of the moving snow as well as the effect of gravity is taken into account. Calculations are made for an impact of low-density avalanches with densities <100 kgm–3 obeying the equation of state for a mixture of two gases (air and gas of ice/snow particles). The pressure, density and velocity distributions in the flow as functions of time and space coordinates are calculated, as well as the variation of the flow depth. In particular, the flow height at the wall, the pressure at the wall and the pressure distribution on the slope near the wall are given, demonstrating peaks and falls due to compression shocks and rarefaction waves.
The connectivity of crystallite agglomerates in low-density firn at Kohnen station, Dronning Maud Land, Antarctica
Authors: Freitag J. , Kipfstuhl S. , Faria S.H.
Published: March 2009

In this study, the three-dimensional (3-D) microstructure of polar firn is investigated by means of X-ray microfocus computer tomography (mCT). Basic topological properties including the Euler and coordination numbers are derived from the reconstructed 3-D volume images. It is shown that sample volumes of about 4 cm3 are representative for polar firn in terms of their connectivity. The connectivity function defined as the change of Euler number with structure size is calculated via image-processing routines. It is used to split the ice phase at small bridges into single crystallite agglomerates. The bond-size distributions and the mean size of the agglomerates are estimated. All μCT measurements were carried out on the uppermost 9 m of a shallow firn core (B35) drilled during the 2005/06 field campaign at Kohnen station, Dronning Maud Land (DML), Antarctica. The results are compared with estimates from classical two-dimensional (2-D) surface section observations. The 3-D approach confirms the linear relationship between coordination number and density which hitherto has only been derived from 2-D observations. Layers of buried snow dunes show a stronger connectivity than layers of moderate crystal size and density. The formation of agglomerates made of crystallites is a common feature of polar firn in DML. It is proposed that the growth of agglomerates leads to reduced critical densities for the transition between the densification regime of grain boundary sliding and plastic deformation.
Changing snow cover and the net mass balance of Storglaciären, northern Sweden
Authors: Evans Eleri , Essery Richard , Lucas Richard
Published: March 2009

The spatial and temporal variability of seasonal snow cover in glacierized catchments has important implications for the net mass balance of alpine glaciers. This study examines the relationship between changing snowpack volume, the resulting winter balance and the net mass balance of Storglaciären, northern Sweden. Using a conceptual model, the net seasonal snow input to the glacier is simulated daily for 16 years from 1990. From this the annual snow accumulation and winter balance are calculated. The model outputs are compared with snowlines delineated from classified aerial photographs, ASTER and Landsat 7 ETM+ satellite imagery, and with measured Storglaciären winter balances. The results of the model indicate variability in the winter balance over the study period, though there is a slightly negative trend overall. The highest winter balances and seasonal snow volumes occurred in the early 1990s and correspond with positive net mass balances. However, the slightly negative trend in winter balance and decreased net seasonal snow volumes suggested by the model, combined with the measured increasing trend in mass lost due to ablation, have resulted in decreasing glacier net mass balances and a corresponding rise in ELA over the study period.
Spatial heterogeneity in snow water equivalent induced by forest canopy in a mixed beech–fir stand in the Pyrenees
Authors: Ignacio López-Moreno J. , Latron J.
Published: March 2009

This paper analyzes the effect of forest canopy on snow water equivalent during two consecutive snow seasons in a mixed beech–fir stand in the Pyrenees. The results confirm that the forest canopy is a dominant influence on snowpack distribution during the accumulation and melting periods. In general, a noticeable decrease in snow water equivalent and an increase in variability among observations are detected with increasing density of the forest canopy. The influence of the forest canopy on melting rates is complex and highly dependent on the dominant climatic conditions. Similar conclusions are reached for both of the snow seasons for which measurements are available, but several differences are also recorded. This study highlights the important influence of climatic conditions observed during the snow season on the relationship between stand characteristics and snowpack dynamics.
Site-specific analog weather-forecast system for northwest Himalaya, India
Authors: Singh Dan , Singh Amreek , Ganju Ashwagosha
Published: March 2009

In an analog weather-forecasting procedure, recorded weather in the past analogs corresponding to the current weather situation is used to predict future weather. Consistent with the procedure, a theoretical framework is developed to predict weather at a specific site in the Pir Panjal range of the northwest Himalaya, India, using surface weather observations of the past ten winters (1991/92 to 2001/02) 3 days in advance. Weather predictions were made as snow day with quantitative snowfall category or no-snow day, for day1 through day3. As currently deployed, the procedure routinely provides a 3 day point weather forecast as guidance information to a weather and avalanche forecaster. Forecasts by analog model are evaluated by the various accuracy measures achieved for an independent dataset of three winters (2002/03 to 2004/05). The results indicate that weather forecasts by analog model are quite reliable, in that forecast accuracy corresponds closely to the relative frequencies of observed weather events. Moreover, qualitative weather (snow day or no-snow day) and quantitative categorical snowfall forecasts (quantitative snowfall category for snow day) are better than reference forecasts based on persistence and climatology for day1 predictions. Site-specific snowfall forecast guidance may play a major role in assessing avalanche danger, and accordingly formulating an avalanche forecast for a given area in advance.
Studies on Smoke Opacity of Different Type of Diesel Vehicles in Dhaka City
Authors: Rouf MA , Hasib HH , Nasiruddin M
Published: March 2009

Six hundred and four diesel vehicles were tested for smoke opacity from September 2001 to December 2004 in Dhaka City. Type of diesel vehicles were single decker, double decker, minibus, jeep and microbus, mini truck, human hauler and maxi, pickup and mini covered van, truck and cover van. Tests conducted on mini truck, maxi and human hauler revealed that about 90% of these vehicles had smoke opacity more than 90 HSU and were not fit to ply on the city roads. The study on pick up and mini cover vans revealed that about 71% of the vehicles had smoke opacity more than 90 HSU. 60.2% mini buses showed smoke emission more than 80 HSU. Most of the single decker and double decker buses had smoke opacity within permissible level of 80 HSU. No correlation has been found between the age of the vehicles and emission of smoke from them. Keywords: Smoke opacity, Gross polluter, Emission study, Air pollution doi: 10.3329/bjsir.v43i4.2247 Bangladesh J. Sci. Ind. Res. 43(4), 559-570, 2008
FLEXIBILITY IN HIGHWAY NOISE MANAGEMENT
Authors: Paslawski Jerzy
Published: March 2009

The problem of noise management was taken as a key element of our life comfort. An adequate noise mitigation plan must be elaborated and implemented for a number of potential noise sources. The general idea of FLENO‐MA2 (FLExibility NOise MAnagement for A2 POZNAN BY‐PASS) advisory system was based on flexibility options situated on different management levels. In the recent years, two significant noise sources have been established in Poznan agglomeration: POZNAN BY‐PASS A2 as a part of A2 highway (BERLIN‐MOSCOW) and the NATO aircraft base in Krzesiny. Both are situated in the urban area of Poznan city. Special emphasis will be placed on flexibility noise mitigation options as an example of operational decision‐aid. However, finding a compromise solution based on diffused (using the Internet) information about the noise map (will be present in the near future) is the second goal of this system.
CAR ROLLOVER COLLISION WITH PIT CORNER
Authors: Viba Janis , Liberts Gundars , Gonca Vladimirs
Published: March 2009

The paper presents a theory of body collision with pit corner. The theory can be successfully applied in approaching tasks coping with the orientation of details in technological processes and control systems, the motion of elements in mechanisms having a gap, collisions in motion of different sport objects, the analysis of car accidents etc. The applied theory deals with car motion after collision with a specific obstacle i.e. pit corner. The study is based on linear and angular momentum theorems and two restitution coefficients of normal impulse from both sides of the obstacle. The obtained results can be used for assessing road accidents in case of car collision with one or more obstacles. The object of contact may involve hitting a plane foundation, the ditch and edging of a highway or a rock in the field.
Characteristics of Solution‐Processed Small‐Molecule Organic Films and Light‐Emitting Diodes Compared with their Vacuum‐Deposited Counterparts
Authors: Lee Tae‐Woo , Noh Taeyong , Shin Hee‐Won , Kwon Ohyun , Park Jong‐Jin , Choi Byoung‐Ki , Kim Myeong‐Suk , Shin Dong Woo , Kim Yong‐Rok
Published: March 2009

Although significant progress has been made in the development of vacuum‐deposited small‐molecule organic light‐emitting diodes (OLEDs), one of the most desired research goals is still to produce flexible displays by low‐cost solution processing. The development of solution‐processed OLEDs based on small molecules could potentially be a good approach but no intensive studies on this topic have been conducted so far. To fabricate high‐performance devices based on solution‐processed small molecules, the underlying nature of the produced films and devices must be elucidated. Here, the distinctive characteristics of solution‐processed small‐molecule films and devices compared to their vacuum‐deposited counterparts are reported. Solution‐processed blue OLEDs show a very high luminous efficiency (of about 8.9 cd A–1) despite their simplified structure. A better hole‐blocking and electron‐transporting layer is essential for achieving high‐efficiency solution‐processed devices because the solution‐processed emitting layer gives the devices a better hole‐transporting capability and more electron traps than the vacuum‐deposited layer. It is found that the lower density of the solution‐processed films (compared to the vacuum‐deposited films) can be a major cause for the short lifetimes observed for the corresponding devices.
Organic Photovoltaic Cells Based On Solvent‐Annealed, Textured Titanyl Phthalocyanine/C60 Heterojunctions
Authors: Placencia Diogenes , Wang Weining , Shallcross R. Clayton , Nebesny Kenneth W. , Brumbach Michael , Armstrong Neal R.
Published: March 2009

Organic photovoltaic cells (OPV) with good near‐IR photoactivity are created from highly textured titanyl phthalocyanine (TiOPc)/C60 heterojunctions. Vacuum deposited TiOPc thin films are converted to the near‐IR absorbing “Phase II” polymorph using post‐deposition solvent annealing. The Phase I → Phase II transition broadens the absorbance spectrum of the Pc film producing absorptivities (α ≈ 105 cm−1) from 600–900 nm, along with substantial texturing of the Pc layer. Atomic force microscopy and field‐emission scanning electron microscopy of the solvent annealed films show that the surface roughness of the Pc layers is increased by a factor of greater than 2× as a result of the phase transformation. Current–voltage (J–V) responses for white light illumination of ITO (100 nm)/TiOPc (20 nm)/C60 (40 nm)/BCP (10 nm)/Al (100 nm) OPVs show a near doubling of the short‐circuit photocurrent (JSC), with only a small decrease in open‐circuit photopotential (VOC), and a concomitant increase in power conversion efficiency. Incident photon current efficiency (IPCE) plots confirmed the enhanced near‐IR OPV activity, with maximum IPCE values of ca. 30% for devices using Phase II‐only TiOPc films. UV‐photoelectron spectroscopy (UPS) of TiOPc/C60 heterojunctions, for both Phase I and Phase II TiOPc films, suggest that the Phase II polymorph has nearly the same HOMO energy as seen in the Phase I polymorph, and similar frontier orbital energy offsets, EHOMOPc–ELUMOC60, leading to comparable open‐circuit photovoltages. These studies suggest new strategies for the formation of higher efficiency OPVs using processing conditions which lead to enhance near‐IR absorptivities, and extensive texturing of crystalline donor or acceptor films.
Scheduling dispensing and counting in secondary pharmaceutical manufacturing
Authors: Ciavotta Michele , Meloni Carlo , Pranzo Marco
Published: March 2009

In this article, we describe a general methodology for operations scheduling in dispensing and counting departments of pharmaceutical manufacturing plants. The departments are modeled as a multiobjective parallel machines scheduling problem under a number of both standard and realistic constraints, such as release times, due dates and deadlines, particular sequence‐dependent setup times, machine unavailabilities, and maximum campaign size. Main characteristics of the methodology are the modularity of the solution algorithms, the adaptability to different objectives and constraints to fulfill production requirements, the easiness of implementation, and the ability of incorporating human experience in the scheduling algorithms. Computational experience carried out on two case studies from a real pharmaceutical plant shows the effectiveness of this approach. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Microcephaly, microtia, preauricular tags, choanal atresia and developmental delay in three unrelated patients: A mandibulofacial dysostosis distinct from Treacher Collins syndrome
Authors: Wieczorek Dagmar , Gener Blanca , González Ma Jesús Martínez , Seland Saskia , Fischer Sven , Hehr Ute , Kuechler Alma , Hoefsloot Lies H. , de Leeuw Nicole , Gillessen‐Kaesbach Gabriele , Lohmann Dietmar R.
Published: March 2009

Treacher Collins syndrome (TCS, OMIM 154500) is a well‐defined mandibulofacial dysostosis characterized by symmetric facial anomalies consisting of malar hypoplasia, coloboma of the lower eyelid, dysplastic ears, micrognathia, cleft palate and deafness. Other mandibulofacial dysostoses (MDs) such as Toriello (OMIM 301950), Bauru (OMIM 604830), Hedera–Toriello–Petty (OMIM 608257), and Guion‐Almeida (OMIM 610536) syndromes are less well characterized and much rarer. Here we describe three unrelated patients showing clinical features overlapping with TCS, but who in addition have developmental delay, microcephaly and a distinct facial gestalt. Because of the distinct ear anomalies and the hearing loss a HOXA2 mutation was taken into account. CHARGE syndrome was discussed because of ear anomalies, choanal atresia, and developmental delay in our patients. But mutational analyses including sequencing of the TCOF1, the HOXA2, and the CHD7 genes, deletion screening of the TCOF1 gene as well as genomewide array analyses revealed normal results. We suggest that these three patients have a new type of mandibulofacial dysostosis. As all three cases are sporadic and both sexes are affected the pattern of inheritance might be autosomal dominant or autosomal recessive. Identification of additional patients will allow to further delineate the phenotype, to assign the inheritance pattern and to identify the molecular basis. © 2009 Wiley‐Liss, Inc.
Hermansky–Pudlak syndrome in two African‐American brothers
Authors: Merideth Melissa A. , Vincent Lisa M. , Sparks Susan E. , Hess Richard A. , Manoli Irini , O'Brien Kevin J. , Tsilou Ekaterina , White James G. , Huizing Marjan , Gahl William A.
Published: March 2009

Hermansky–Pudlak syndrome (HPS) is an autosomal recessive disorder characterized by oculocutaneous albinism, a bleeding disorder, and, in some patients, granulomatous colitis and/or a fatal pulmonary fibrosis. There are eight different subtypes of HPS, each due to mutations in one of eight different genes, whose functions are thought to involve intracellular vesicle formation and trafficking. HPS has been identified in patients of nearly all ethnic groups, though it has primarily been associated with patients of Puerto Rican, Northern European, Japanese and Israeli descent. We report on the diagnosis of HPS type 1 in two African‐American patients. Both brothers carried compound heterozygous mutations in HPS1: previously reported p.M325WfsX6 (c.972delC) and a novel silent mutation p.E169E (c.507G > A), which resulted in a splice defect. HPS may be under‐diagnosed in African‐American patients and other ethnic groups. A history of easy bruising or evidence of a bleeding disorder, combined with some degree of hypopigmentation, should prompt investigation into the diagnosis of HPS. Published 2009 Wiley‐Liss, Inc.
Click Chemistry for the Identification of G‐Quadruplex Structures: Discovery of a DNA–RNA G‐Quadruplex
Authors: Xu Yan , Suzuki Yuta , Komiyama Makoto
Published: March 2009

Die Falle schließt mit einem „Klick“: G‐Quadruplexstrukturen können durch Kupfer‐katalysierte Azid‐Alkin‐Cycloaddition (Klick‐Reaktion) fixiert und dann getrennt und analysiert werden (siehe Schema). Ein hybrider DNA‐RNA‐Quadruplex bestehend aus humaner telomerer DNA und RNA wurde mit dieser Methode entdeckt.

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Preparation and characterization of a solid polymer electrolyte PEO‐ENR50 (80/20)‐LiCF3SO3
Authors: Noor S. A. M. , Ahmad A. , Rahman M. Y. A. , Talib I. A.
Published: March 2009

The preparation and characterization of a polymer electrolyte films containing 80 wt % of poly (ethylene oxide) (PEO) and 20 wt % epoxidized natural rubber (ENR50) complexed with LiCF3SO3 has been reported. The ac impedance data showed good conducting properties of the solid polymer electrolyte (SPE) films. The greatest room temperature ionic conductivity of 7.5 × 10−5 S cm−1 was obtained at 25 wt % of LiCF3SO3 salt. This result has been supported by differential scanning calorimeter and X‐ray diffraction analysis. Analysis differential scanning calorimetry showed the relative percentage of crystallinity and Tm of PEO decreased with the increasing wt % of LiCF3SO3. Analysis with X‐ray diffraction suggested that the semicrystalline nature of PEO turned to amorphous due to the presence of LiCF3SO3. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Application of urea/H2O2 activation‐oxidation system in degradation of PVA and desizing of polyester/cotton fabric
Authors: Shan Juchuan , Guan Yu , Zheng Qingkang , Han Jinshi , Liu Qingshu , Pu Zhongyao
Published: March 2009

The viscosity and the UV–vis spectrum of PVA degradation aqueous solutions, the FTIR, and DSC spectrums of degradation products were measured to investigate and compare the effect of Fenton's reagent and urea/H2O2 activate oxidation systems on the degradation of PVA. The results showed that the viscosity of PVA aqueous solution decreased and the degradation rate of PVA increased with the concentration of hydrogen peroxide in both activate oxidation systems. The FTIR and DSC spectrum of degradation products showed that the degradation products contained aldehyde, ketone groups. The aldehyde compounds and carbon dioxide produced in the degradation systems were validated by Fehling reagents and clarifying limewater. When the urea/H2O2 system was applied in the one‐bath and one‐step desizing and scouring process of polyester/cotton 65/35 fabric, the results of 94.7% degradation rate of PVA, the 99.0% desizing rate of PVA, the whiteness, and wicking height of the fabric were obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and photopolymerization kinetics of multifunctional aliphatic urethane acrylates containing the tertiary amine group
Authors: Zhang Jing , Xiao Pu , Shi Suqing , Nie Jun
Published: March 2009

Two multifunctional aliphatic urethane acrylates, based on isophorone diisocyanate (IPDI), β‐hydroxyethyl arcylate (HEA), and synthetic multifunctional hydroxyl compounds, were synthesized by classical condensation reaction. FTIR was used to monitor the process of the reaction. The photopolymerization kinetics of the urethane acrylates with different photoinitiators was studied by real‐time infrared spectroscopy. The results indicated that compared with the commercial hexa‐functional urethane acrylate CN 9010, the synthetic multifunctional urethane acrylates could be initiated by benzophenone more efficiently without the addition of any coinitiators because they have tertiary amine structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Condensation on vertical porous metal fins
Authors: Sarma P. K. , Mayinger Franz
Published: March 2009

The problem of condensation of vapors on a porous plate fin is formulated and the dimensionless heat transfer coefficients are found to be dependent on two system variables, viz., the fin and the porosity parameters. Numerical simulations indicated that the condensation heat transfer coefficients for a porous fin are larger than those for a non‐porous one of similar cross‐section. For design purposes, a dimensionless equation for predicting the mean condensation heat transfer coefficient is proposed.

The significant increase in the condensation heat transfer coefficient suggests that the condenser section of a flat plate heat pipe can be made more efficient in operation with the use of porous plate fins instead of impermeable fins of similar cross‐section.
Aerodynamics and heat transfer during coating of tablets in two‐dimensional spouted bed
Authors: Rocha S. C. S. , Taranto O. P. , Ayub G. E.
Published: March 2009

The two‐dimensional spouted bed has been pointed out in recent research works as an improved configuration of spouted beds. The main advantages in relation to the conventional spouted beds are the easy construction and scale‐up. In this work we begin the study of coating of tablets in two‐dimensional spouted beds. An experimental system was constructed and the data obtained were used to determine the values of maximum pressure drop, minimum spout flowrate and gas‐to‐particle heat transfer coefficient, for 36 process conditions. The experimental results have been correlated with process and geometrical parameters.
Liquid‐Solid mass transfer in a slurry bubble column and a gas‐liquid‐solid three‐phase fluidized bed
Authors: Kikuchi Ken‐Ichi , Takahashi Hiroshi , Sugawara Takuo
Published: March 2009

Mass transfer coefficients between particles and liquids in a slurry bubble column and a three‐phase fluidized bed containing small size particles were obtained with two mass transfer systems: (1) K+ –Na+ ion‐exchange in cation‐exchange resin bead beds, including anion‐exchange resin beads as inert particles; (2) zinc dissolution by HCl in zinc‐plated glass bead beds, and in beds of non‐plated glass beads. Operating parameters were gas velocity, liquid velocity, particle diameter, and particle concentration. The dependence of mass transfer coefficients on these parameters is discussed from the viewpoint of the energy supplied into the systems. Correlations of the experimental data using dimensionless groups are compared to previous correlations.
Improving membrane performance for nitrogen production from air
Authors: Spagnolo D. A. , Chuang K. T. , Pan C. Y.
Published: March 2009

Using a portion of the product N2 to purge the permeate side of a membrane module in order to reduce the membrane area for the separation of air for nitrogen production is considered. A simulation program was developed and used to compare a purge system to a conventional non‐purge permeator. Both the selectivity of the membrane and the feed/permeate pressure ratio were found to affect the ability of the purge stream to reduce the membrane area. The purge stream reduces the recovery of nitrogen, which results in a minimum in the membrane area per unit of product flow.
Comparative reactivity of treated FBC‐ and PCC‐Fly ash for SO2 removal
Authors: Al‐Shawabkeh Ali , Maisuda Hitoki , Hasatani Masanobu
Published: March 2009

Two types of fly ash from fluidized bed (FBC) and pulverized coal combustors (PCC) were treated with calcium hydroxide (Ca(OH)2) to produce reactive SO2 sorbents. Treatment was performed using 28.6 mass% Ca(OH)2/fly ash mixtures slurried at 350 K for 8 h. Sulfation experiments were carried out in a thermogravimetric analyzer (TGA) at SO2 concentration ranging from 0.11 to 0.67 vol% and 10(53–1153 K temperature range. At conditions close to those prevailing in an atmospheric FBC (1123 K, 3000 ppmv ami 20 vol% excess air), about 92% and complete conversion of CaO to CaSO4 within 1 h reaction could be achieved with treated PCC and FBC fly ashes, respectively.

Based on pore structural measurements for both sorbents, treatment enhanced the specific surface area (by about 8 times) as well as pore volume (by about 5 times). The shape of the N2‐adsorption/desorption isotherms, specific pore area, and pore volume distribution curves remained unchanged.

Study of the intrinsic kinetics of the reaction between treated fly ash and S02 indicated a first order reaction with respect to SO2 concentration up to 0.31 vol% SO2 (3.36 × 10−8 mol/cm3). Activation energies of 82.3 and 89.0 kJ/mol were calculated for treated PCC and FBC fly ashes, respsctively.
Preparation and testing of polyvinyl alcohol composite membranes for reverse osmosis
Authors: Lang K. , Matsuura T. , Chowdhury G. , Sourirajan S.
Published: March 2009

Thin film composite membranes were prepared by coating porous polysulfone membranes with a polyvinyl alcohol layer and further cross‐linking its surface. The thin layer of cross‐linked polyvinyl alcohol served as a selective membrane. The membranes were prepared under various conditions and tested for sodium chloride separation. A high sodium chloride separation was achieved but the permeation rate was low compared with commercially available thin film composite membranes. Resistance against the flow of solvent water and sodium chloride solute were determined for individual component barrier layers.
Particle mixing/segregation in gas‐solid fluidized bed of ternary mixtures
Authors: Wang Rong‐Chi , Chou Ching‐Chang
Published: March 2009

The particle concentration profiles and minimum fluidizing velocity of ternary mixtures were investigated experimentally. All the experiments were carried out in an 88 mm I.D. transparent acrylic column containing fluidized beds of ternary particles of different sizes, densities and shape. Mixing/segregation patterns were visualized under different operating conditions. The experimental results are compared with empirical relationships for mixing index and take‐off velocity. A new definition of the mixing index, including particle minimum fluidizing velocity and density predicted the mixing/segregation behaviour reliably. The proposed correlation of take‐off velocity agrees with the experimental results very well.
Model discrimination by unsteady‐state operation: Application to the reduction of no with co on iron oxide
Authors: Randall H. , Doepper R. , Renken A.
Published: March 2009

The steady‐state catalytic reduction of NO with CO on iron oxide was described with three different models, which all fit the experimental data equally well. By applying the transient method to this reaction, it has been shown that for reduced catalysts without adsorbed CO, the N2O reduction step is well described qualitatively by two of the models, whereas only one of them can describe the NO reduction step. In the presence of adsorbed CO, however, none of these models can explain the observed transient behaviour. Therefore, a modification of the best model was proposed and tested via computer simulation, which showed good agreement with transient experiments.
Identification of heat load loops and downstream paths in heat exchanger networks
Authors: Zhu J. , Han Z. , Rao M. , Chuang K. T.
Published: March 2009

To achieve the optimal trade‐off between economies and operability, simplifications of heat exchanger networks (HENs) are required. To do so, identifications of heat load loops and downstream paths are necessary. This paper proposes new methods for identifications of independent and dependent loops as well as downstream paths in HENs, respectively. Stream table and node adjacency matrix are defined in this paper to represent the structures of HENs. Based on graph theory, identification of loops in HENs is decomposed into three procedures: (a) finding a maximal tree, (b) identifying a maximal set of independent loops and (c) searching all loops. Locating the downstream paths in HENs is accomplished by finding directed trees which are generated by modifying the procedure for finding a maximal tree. A complex network with a splitting stream is used for detailed illustrations of the procedures.
Calcium carbonate deposit formation under isothermal conditions
Authors: Andritsos N. , Kontopoulou M. , Karabelas A. J. , Koutsoukos P. G.
Published: March 2009

Scale formation of calcium carbonate on tube walls is studied in a once‐through flow system under isothermal conditions. The effects of supersaturation ratio, flow velocity and liquid temperature on the deposition rates are investigated. For relatively small supersaturation ratios (in the range 3.5 to 8) the deposition rate tends to increase with increasing supersaturation. For higher fluid supersaturations with respect to calcium carbonate, the deposition rates remain roughly constant but they are influenced strongly by the fluid velocity. This dependence of the deposition rate on fluid flow suggests a mass transfer‐controlled process.
A contribution to the modeling of kraft pulping
Authors: Agarwal Niraj , Gustafson Rick
Published: March 2009

This paper presents a mathematical model for pulping that considers the effect of alkali diffusion and chemical reaction. An approximation for 3‐dimensional diffusion in wood chips is tested against pulping data. A method for predicting pulp viscosity is also presented. The model simulates the effect of key pulping variables on pulp kappa number, viscosity, yield, residual alkalinity and pulping uniformity. Experimental data from a number of sources are successfully predicted by the model.
Gas—liquid dispersion and mixing characteristics and heat transfer in a stirred vessel
Authors: Xu G. J. , Li Y. M. , Hou Z. Z. , Feng L. F. , Wang K.
Published: March 2009

Properties of gas—liquid dispersion and mixing of seven types of impellers were studied and compared in a stirred vessel with aeration. New correlations for the properties including critical dispersion impeller speed, dispersion regime, power consumption, gas hold‐up, discharge flow number and discharge efficiency have been developed.

The fluid/wall heat transfer was also studied with several types of dual impeller combinations. There is a critical impeller speed which determines how aeration changes the heat transfer coefficient. Operating conditions influence heat transfer interactively by three factors, which can be expressed by proper dimensionless variables.
Modelling a circulating fluidized bed riser reactor with gas—solids downflow at the wall
Authors: Puchyr David M. J. , Mehrotra Anil K. , Behie Leo A. , Kalogerakis Nicolas E.
Published: March 2009

A predictive model was developed for the fully developed zone of a circulating fluidized bed (CFB) riser reactor operating in the fast fluidization regime that overcomes limitations of existing models. The model accounts for the upward flow of gas and solids in the core and downward flow of the two phases in the annulus. Additionally, a numerical solution methodology for the simulation of a riser reactor employing the hydrodynamic model was devised. A simulation was performed using the fast, main Claus reaction to demonstrate the effects of backmixing in the fast fluidization regime. It was found that the molar flow rates of the reactants leaving a fast fluidized CFB riser reactor were significantly higher than those leaving an identical reactor operating in the pneumatic transport regime.
Investigation of coke extraction from zeolite‐HY under supercritical and near‐critical conditions
Authors: Niu Fenghui , Hofmann Hanns
Published: March 2009

In‐situ regeneration of deactivated catalysts by dissolving coke or coke precursors with supercritical reaction fluids is of important economical significance. Investigations of coke extraction on zeolite‐HY were performed in a gradientless reactor under supercritical and near‐critical conditions with ethylbenzene disproportionation as a test reaction and n‐butane or n‐pentane as inert. Experimental results illustrate the large ability of coke extraction under supercritical conditions. The influences of the experimental conditions on the ethylbenzene disproportionation and the coke extraction are discussed. Under appropriate supercritical conditions the coking and the coke extraction can reach an equilibrium, so that no further deactivation of the catalyst was observed. Several regularities about coke extraction on the surface of the catalyst are proposed.
Study on a cool storage system using HCFC (Hydro‐Chloro‐Fluoro‐Carbon)‐141B (CCI2 FCH3) (1, 1‐dichloro‐1‐fluoro‐ethane) clathrate
Authors: Tanii T. , Minemoto M. , Nakazawa K. , Ando Y.
Published: March 2009

An experimental study was performed to obtain design data for a cool storage system using HCFC‐141b (1, 1‐dichloro‐1‐fluoro‐ethane) clathrate, which is a more effective cool storage system than ice. The addition of a 0.05 mass% surfactant enabled HCFC‐141b clathrate formation/decomposition up to 40 mass% of clathrate concentration. The addition of ethylene glycol caused the clathrate formation/decomposition temperature to decrease, resulting in the acquisition of more cooled water.
Prediction of solubility for HFC working fluids in model substances for compressor oils
Authors: Wahlström åsa , Vamling Lennart
Published: March 2009

This study is a first step towards the prediction of the behaviour of working fluids and compressor oils. Different thermodynamic models are investigated and a modified Flory‐Huggins‐based predictive model, termed MFH, is proposed for solubility of HFCs in long‐chained hydrocarbons. From experimental data, 7 general parameters have been fitted for the MFH model to describe 14 binary systems. The UNIQUAC model demands 28 specific parameters without the possibility of extending their validity to other mixtures. A predictive UNIFAC model requires 8 general parameters, but its uncertainty, 17%. is poor compared to the MFH model's 7%.
Gas permeation and isobutane dehydrogenation over very thinPd/ceramic membranes
Authors: Shu J. , Grandjean B. P. A. , Kaliaguine S. , Ciavarella P. , Giroir‐Fendler A. , Dalmon J.‐A.
Published: March 2009

An attempt was made in this study to prepare very thin palladium membranes.Pdwas electrolessly deposited on the inner side surface of a mesoporous ceramic tube using a peristaltic pump to circulate the electroless solution through the tube. To obtain defect‐freePdmembranes, a two‐step deposition procedure from a dilutePd2+bath and a concentratedPd2+bath was practised with great care to avoid the difficulties associated with the mismatch of thermal expansion coefficients betweenPdand the ceramic substrate. The various membranes produced were characterized through a study of their permeation behaviors. A densePdmembrane about 2 μm thick was permselective to hydrogen. It was found that in this very thinPdmembrane case, the hydrogen permeation flux was better correlated to hydrogen pressure using a power higher than 0.5, showing deviation from Sieverts' law. To evaluate the efficiency of the prepared thinPd/ceramic membranes,iso‐butane dehydrogenation was used as a model reaction. Enhanced dehydrogenation yields were obtained in the membrane reactor due to the separation of hydrogen from the reaction medium.
Flow patterns in a pilot plant‐scale turbulent fluidized bed reactor: Concurrent application of tracers and fiber optic sensors
Authors: Farag H. I. , Grislingås A. , Ege P. E. , De Lasa H. I.
Published: March 2009

Hydrodynamics of a turbulent fluidized bed is studied by means of the concurrent application of fiber optic sensors and a helium tracer.

It is observed that in the vicinity of the column wall there is a high bubble activity region. Low bubble activity and negative bubble velocities are reported for the dense phase near the column centre‐line region.

A temperature increase from 22 to 145°C results in a more homogeneous turbulent fluidized bed with smaller bubbles and more gas flowing through an expanded dense bed emulsion phase.

Mass transfer coefficients between bubble‐emulsion (kbe) and bubble‐annulus (kba) are evaluated. The dominant mass transfer path was the one from the bubbles to the annular region with kba being several times greater than kbe.
Methyl‐diethanolamine degradation — Mechanism and kinetics
Authors: Chakma A. , Meisen A.
Published: March 2009

Methyl‐diethanolamine (MDEA) degradation reactions between aqueous solutions of MDEA and CO2 have been carried out in a 600 mL stirred autoclave under the following conditions: initial MDEA solution concentration 20‐50 mass%, solution temperature 100‐200°C, CO2 partial pressure 1.38‐4.24 MPa. It was found that MDEA degrades quite rapidly (although more slowly than diethanolamine under comparable conditions) at elevated temperatures and CO2 partial pressures. Degradation products are identified by gas chromatography and mass spectrometry (GC/MS). An MDEA degradation reaction mechanism and kinetic model predicting concentration changes is proposed and verified.
Mass transfer in horizontal flow channels with thermal gradients
Authors: Bendrich Guido , Shemilt Leslie W.
Published: March 2009

Mass transfer to a wall of a horizontal rectangular channel reactor was investigated by the limiting current technique for Reynolds numbers ranging from 200 to 32000. Overall mass transfer coefficients at various mass transfer surface angles were obtained while the reactor was operated under isothermal and non‐isothermal conditions. Dimensionless correlations were developed for isothermal flows from 25 to 55°C and for non‐isothermal flows with applied temperature differences up to 30°C. In the laminar flow range natural convection dominated, but under turbulent conditions combined natural and forced convection prevailed. Mass transfer was approximately doubled under optimum selection of channel surface rotation, temperature gradient and flow rate.
Nucleation site density in pool boiling of binary mixtures: Effect of surface micro‐roughness and surface and liquid physical properties
Authors: Benjamin R. J. , Balakrishnan A. R.
Published: March 2009

The nucleation site density (N/A) during pool boiling of binary mixtures has been experimentally examined in terms of the heating surface physical properties, the liquid physical properties, the vapour liquid equilibria and the surface micro‐roughness. The liquid mixtures used were acetone ‐ carbon tetrachloride and n‐hexane ‐ carbon tetrachloride. A parameter Ra, to characterize the micro‐roughness of the heating surface was defined as the average value of the peaks and valleys on the surface. The study shows that while at low Ra, values the physical properties of the liquid and the binary composition are not as important as the surface roughness; at higher Ra values the liquid properties and composition are also important. A correlation based on the present data has been proposed.
Alkaline cupric oxide and nitrobenzene oxidation of alcell® lignin
Authors: Hepditch Mona M. , Thring Ronald K
Published: March 2009

A solvolysis lignin has been oxidatively degraded using nitrobenzene and cupric oxide (CuO) as catalysts. The effects of reaction conditions on lignin conversion to identifiable low molecular weight liquid products were quantified. Optimal yields of vanillin and syringaldehyde of 2.2 wt % and 5.9 wt % respectively were obtained using nitrobenzene at 180°C and 2h, whereas both were less than 1 wt % when CuO was used at 225°C and 1h, indicative of the milder oxidative power of CuO for this lignin. The higher total aldehyde yield from solvolysis lignin (8.2 wt %) than kraft lignin (5.1 wt %) when using nitrobenzene indicates it might be a better candidate for producing chemicals via oxidation.
The marangoni effect and enhanced oil recovery Part 2. Interfacial tension and drop instability
Authors: Lyford P. A. , Shallcross D. C. , Pratt H. R. C. , Grieser F.
Published: March 2009

A computer‐based method is described for the determination of the interfacial tension between pendant and sessile drops in a surrounding continuous phase. This has been used to determine the effect on interfacial tension of increasing amounts of aliphatic alcohols, from methanol up to n‐octanol, equilibrated between a hydrocarbon solvent (Shellsol) and water. The results indicated large decreases in interfacial tension, with n‐butanol, followed by n‐propanol giving the greatest reduction. Measurements were also made of the rate of change of interfacial tension during the mass transfer of 2.5% of the alcohols between phases. Changes were observed for all alcohols from ethanol to n‐pentanol, the effect being greatest for transfer into water drops and out of solvent drops. Application of the linear stability theory of Sørensen to these results failed to predict the observed instability for transfer into solvent drops.
The effect of chloride on the HClO2‐HOCl2 reaction in a 4.5 mol/L sulfuric acid solution
Authors: Yin G. , Ni Y.
Published: March 2009

The chlorous acid reaction with hypochlorous acid (chlorine) may be responsible for the chlorine dioxide formation in a methanol based chlorine dioxide generation process. In this paper, the reaction between chlorous acid and hypochlorous acid in a 4.5 mol/L sulfuric acid solution was studied. It was found that chlorine dioxide is generated only if chloride is present. The underlying mechanism associated with the effect of chloride on the reaction was discussed.
Enhancement of the retention performance of the poly(ethylene oxide) — tannic acid system by poly (diallyldimethyl ammonium chloride)
Authors: Khoultchaev K. H. , Pang P. , Kerekes R. J. , Englezos P.
Published: March 2009

The retention performance of the poly(ethylene oxide) (PEO) and tannic acid (TA) dual system was studied in the presence of poly(diallyldimethyl ammonium chloride) (PDADMAC). The zeta potential, and size of the association complex between PEO and TA in the presence of PDADMAC as well as the infrared spectra of TA and the PEO‐TA system were also studied. It was shown that hydrogen bonds are formed between the phenolic and acidic groups of TA and the oxygen atoms of the PEO macromolecules. Moreover, it was found that the presence of small quantities of PDADMAC enhances the fibre fines and clay first pass retention. The maximum effect was observed with an amount of added PDADMAC equal to 20% of the amount of added PEO. Further addition of PDADMAC was found to decrease the retention probably because it re‐charges the surface to positive. When clay was replaced by ground calcium carbonate no retention improvement was detected. This is most likely due to the presence of calcium ions.
Scale‐up of mixing in gassed multi‐turbine agitated vessels
Authors: Vasconcelos Jorge M. T. , Alves Sebastião S. , Nienow Alvin W. , Bujalski Waldemar
Published: March 2009

A mixing model previously developed for the determination of mixing time in gassed tanks stirred by multiple Rushton turbines (Vasconcelos et al., 1995) was verified for the additional scales of 0.39, 0.56 and 0.72 m vessel diameter. It is now shown that the single adjusted parameter previously required by the model, the air‐induced axial velocity parameter vax, is scale‐independent with an invariant value of 7 × 10−2 m/s. Model simulations, with tank and turbine diameters and the number of stages as the only required parameters, deviate 5% on average from the experimentally determined mixing time t0.05. The model is thus a valuable tool for scale‐up of this type of vessels.