bluuebunny/crossref_metadata_2025 huggingface dataset:
Method for predicting solubilities of solids in mixed solvents
Authors: Ellegaard Martin E. , Abildskov Jens , O'Connell John P.
Published: March 2009

A method is presented for predicting solubilities of solid solutes in mixed solvents, based on excess Henry's law constants. The basis is statistical mechanical fluctuation solution theory for composition derivatives of solute/solvent infinite dilution activity coefficients. Suitable approximations are made for a single parameter characterizing solute/solvent interactions. Comparisons with available data show that the method is successful in describing a variety of observed mixed solvent solubility behavior, including nearly ideal systems with small excess solubilities, systems with solute‐independent excess solubilities, and systems deviating from these simple rules. Successful predictions for new solvent mixtures can be made using limited data from other mixtures. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Enantioselective Friedel–Crafts Reactions in Water Using a DNA‐Based Catalyst
Authors: Boersma Arnold J. , Feringa Ben L. , Roelfes Gerard
Published: March 2009

Ins kühle Nass: Bei der ersten Lewis‐Säure‐katalysierten asymmetrischen Friedel‐Crafts‐Alkylierung mit Olefinen in Wasser genügen schon 0.15 Mol‐% eines DNA‐Kupfer‐Katalysators, um in der Reaktion von α,β‐ungesättigten 2‐Acylimidazolen mit heteroaromatischen π‐Nucleophilen gute Ausbeuten und Enantioselektivitäten zu erzielen (siehe Schema; dmbpy=4,4′‐Dimethyl‐2,2′‐bipyridin).

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Use of lignin strengthened with modified wheat gluten in biodegradable composites
Authors: El‐Wakil Nahla A.
Published: March 2009

In this study, composites from alkali lignin and wheat gluten, modified with different percentages of sodium silicate, were prepared and characterized. Moreover, the addition of silica to the aforementioned composites was studied with the aim of improving the thermal and mechanical properties. The effect of wheat gluten percent and the extent of its modification on the blends properties were investigated via diametric tensile strength, thermomechanical analysis (TMA), scanning electron microscope (SEM), thickness swelling and thermogravimetric analysis (TGA). The results showed significant improvement in the diametric tensile strength, thickness swelling, uniformity in the fracture surface, and the shift of glass transition temperature (Tg) toward higher values with increasing wheat gluten percent and its modification extent. These results reflect the enhancement of interaction between alkali lignin and wheat gluten. Alkali lignin/wheat gluten blends filled with silica possessed distinguishable characteristics and improved diametric tensile strength, low thermal expansion, and high Tg. Interestingly, TMA results showed that high dimensional stability against heating (thermal expansion percent) could be obtained using 60% wheat gluten modified with 15% sodium silicate and filled with 10% silica. This sample showed the highest Tg and the lowest thickness swelling in addition to smooth, uniform, and glossy surface as shown from the SEM images and TMA charts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Copper (II) ions and copper nanoparticles‐loaded chemically modified cotton cellulose fibers with fair antibacterial properties
Authors: Mary Grace , Bajpai S. K. , Chand Navin
Published: March 2009

This work describes the release of copper(II) ions from cellulose fibers, which have been chemically modified by periodate‐induced oxidation of cellulose, followed by covalent attachment of biopolymer chitosan. The release of copper(II) ions has been investigated in physiological fluid (PF) and protein solution (PS) both at 37°C. Fibers have demonstrated excellent antibacterial activity againstE. coli. Finally, their borohydride‐induced reduction has yielded copper nanoparticle‐loaded fibers, with average diameter of particles, nearly 28.94 nm. The formation of copper nanoparticles has been established by surface plasmon resonance and FTIR spectroscopy. These fibers also show fair biocidal action againstE. coli. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A spreadsheet model for soccer ball flight mechanics simulation
Authors: Spathopoulos Vassilios M.
Published: March 2009

A mathematical model implemented in a spreadsheet environment is presented for a soccer ball in flight. The simulation is used as part of a project designed to introduce students to basic concepts in the field of flight mechanics. Results are presented for a free kick under various conditions and are consistent to previous studies and to the physical principles governing soccer ball motion in the air. It is concluded that a relatively simple model can be used in order to simulate key aspects of a game of great popularity thus providing students with increased motivation. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 508–513, 2011
An experimental study of non‐newtonian fluid flow through fixed and fluidized beds of non‐spherical particles
Authors: Sharma M. K. , Chhabra R. P.
Published: March 2009

Extensive measurements of pressure drop in fixed beds, minimum fluidization velocity and expansion characteristics for beds of non‐spherical particles are reported in the following ranges of conditions: 10‐3 ≤ Re ≤ 20; 0.66 ≤ n ≤ 1 and 0.41 ≤ ϵ ≤ 0.75. Based on an analysis of these results, it is illustrated that the existing frameworks originally developed for Newtonian fluid flow through beds of spherical particles are also satisfactory for power law fluid flow through beds of non‐spherical particles, provided a volume equivalent diameter modified by a sphericity factor and a modified Reynolds number are used instead of their usual definitions.
Evaluation of capital cost data: Part 9: Liquid waste disposal with emphasis on chemical treatment
Authors: Wright David G. , Woods Donald R.
Published: March 2009

Capital cost correlations are given for chemical feed systems, chlorination, ozone disinfection, ultraviolet light disinfection, ion exchange, flocculation, and carbon adsorption. Most of the correlations are accurate to ± 30%, expressed in Canadian dollars and adjusted to a Marshall and Swift value of 1000. Details as to what components are included in the cost are given. Data are given for the labour and material costs to create a working process module.

To put the current data into perspective, several hundred sources of cost data were analyzed. The major correlations are compared, on a consistent basis, with current data.
Kinetics of the cooling crystallization of sodium sesquisulfate from 4.5 mol/l sulfuric acid
Authors: Nyakiamo Anthony P. , Pinder Kenneth L.
Published: March 2009

Simulating effluent from chlorine dioxide generators, the crystallization kinetics of sodium sesquisulfate from 4.5 mol/L sulfuric acid were studied under cooling conditions. The crystal growth and nucleation rates were determined using the population balance concept and the crystal size distribution from a continuous mixed suspension mixed product removal (MSMPR) crystallizer. Crystallization temperatures studied were 45, 50, 55 and 60°C.

The crystal growth and nucleation rate data were correlated to supersaturation and temperature. Nucleation rate was found to be a function of suspension density (secondary nucleation). The activation energies for nucleation and growth are reported.
Cell growth kinetics and ice nucleation activity of pseudomonas syringae
Authors: Bassi Amarjeet S. , Margaritis Argyrios
Published: March 2009

The bacterium Pseudomonas syringae causes freezing of supercooled water at temperatures close to 0°C. In this study, the growth kinetics and ice nucleation activity (INA) of the bacterium P. syringae pv. syringae cit 7 were investigated in a batch and continuously operated laboratory scale bioreactor system. Under continuous culture conditions, the bacterial INA decreased with an increase in dilution rate. The maximum biomass and INA productivities were obtained at a dilution rate of 0.054 hr−1 at 25°C and pH 7.0. The results of this investigation can be applied towards the large scale production of P. syringae bacteria for snow making and other commercial applications of ice nucleation.
Kinetics of alkaline hydrolysis of 2‐ethylbutylformate
Authors: Chaudhuri Basab , Bhattacharjee Sekhar , Dutta Binay K.
Published: March 2009

The theory of mass transfer accompanied by chemical reaction has been used for studying the kinetics of alkaline hydrolysis of 2‐ethylbutylformate at different temperatures and ionic strengths of aqueous alkaline solution. Experiments have been conducted in a stirred cell having a flat liquid‐liquid interface. For aqueous phases containing 1–3 kmol/m3 sodium hydroxide, the alkaline hydrolysis conforms to the fast pseudo‐first order reaction regime. The system is of considerable practical importance and can be successfully employed for the measurement of the interfacial area of a mechanically‐agitated and flooded packed‐bed liquid‐liquid contactor.
Liquid phase residence time distribution for two phase flow in coiled tubes
Authors: Saxena A. K. , Nigam K. D. P. , Schumpe A. , Deckwer W. D.
Published: March 2009

The residence time distribution (RTD) of the liquid phase in air‐water flow through helical coils has been studied. Upward and downward cocurrent flows have been investigated in three coils with curvature ratios ranging from 11 to 60.7. The ranges of the Reynolds numbers for the gas and the liquid varied from 1500 to 3000 and 620 to 3200, respectively. A model has been proposed that describes the liquid phase RTD as combination of two different residence time distributions applicable for turbulent and laminar liquid flows.
Modelling of phase redistribution of horizontal annular flow divided in T‐junctions
Authors: Peng F. , Shoukri M.
Published: March 2009

A phase redistribution model for annular flow divided in T‐junctions is developed. The model consists of two sub‐models accounting for phase distribution in the inlet to the junction and phase redistribution in the junction, respectively. In modelling phase redistribution in the junction, the dividing streamlines for each phase were determined separately assuming that the phenomena is mainly governed by the fluid inertia and pressure distribution in the junction. The overall model is capable of predicting phase redistribution in T‐junctions having horizontal inlet and any branch orientation. The predictions of this model and those of other available models are compared with experimental data. The predictions of the present model were found to be in better agreement with the experimental data than other available models and correlations.
Viscoplastic fluid flow in irregular eccentric annuli due to axial motion of the inner pipe
Authors: Hussain Quazi E. , Sharif Muhammad A. R.
Published: March 2009

Fully developed axial laminar flow of viscoplastic Herschel‐Bulkley fluids in eccentric annuli between two pipes has been investigated numerically. The pipes are closed at one end and flow is due to the axial motion of the inner pipe. The annuli may be filly open or partially blocked. General non‐orthogonal, boundary‐fitted curvilinear coordinates have been used to accurately model the irregular annular geometry due to the presence of a flow blockage. A computer code has been developed using a second‐order finite‐difference scheme. An exponential model for the shear stress, valid for both yielded and unyielded regions of the flow, is used in the computation. The effects of generalized Bingham number, flow behavior index, eccentricity, and blockage height on the pressure gradient or the surge pressure have been studied and the results are presented in dimensionless form. The pressure gradient is found to decrease with increasing eccentricity. For a partially blocked eccentric annulus the pressure gradient is found to decrease with an increase in the blockage height.
The interaction of solute transfer, contaminants and drop break‐up in rotating disc contactors: Part I. Correlation of drop breakage probabilities
Authors: Cauwenberg Veerle , Degrève Jan , Slater Michael J.
Published: March 2009

The breakage process of single drops in RDC liquid‐liquid extraction columns has been investigated. The breakage probability and daughter drop size distribution were the measured characteristics. Binary systems, non‐equilibrated ternary systems with mass transfer in both directions (c → d and d → c) and systems with surface active agent added were used in the experiments. A model of the breakage probability was developed based on a modified Weber number, taking into account the applied shearing stress and the resisting interfacial tension force. It is shown that breakage probability can be estimated if interfacial tension is known as a function of interfacial conditions.
In situ rheological monitoring in semi‐batch emulsification process for cosmetic lotion production
Authors: Choplin Lionel , Torandell Sandrine , Servoin Jacques
Published: March 2009

In situ rheological monitoring of a semi‐batch emulsification process for the production of a simplified cosmetic lotion formulation has been realized in a rheo‐reactor (100 mL volume), which consists of a small‐scale reactor connected to a rheometer. The torque evolution as well as the mechanical spectrum evolution has been reported for two different protocols. It has been shown that the evolution of the rheological properties of the macroemulsion seems to be governed by the gelification of the continuous aqueous phase. In situ rheological characterizations of the macroemulsion at the end of the process, under controlled mechanical history mimicking somehow post‐processing “real life” of the cosmetic lotion, have shown that the stability can be significantly influenced by the process protocol.
Spout diameters in full and half spouted beds
Authors: He Ayn‐Long , Lim Choon J. , Grace John R. , Qin Shao‐Zhong
Published: March 2009

A fiber optic probe has been used to measure spout diameters in a half‐column and a full‐column based on the significantly higher counts of output electric pulses in the spout region than in the annulus. The flat wall of a semi‐cylindrical spouted bed column was found to cause considerable distortion of spout shapes which became approximately semi‐elliptical in cross‐section. Caution must therefore be exercised when using spout diameter data from the face of half‐columns for spouted bed modelling and design. The often‐used McNab (1972) equation was found to underestimate the spout diameters in the full‐column, with an average deviation of 35.5%.
Influence of ring‐type internals on axial pressure distribution in circulating fluidized bed
Authors: Bu Jianjie , Zuh Jing‐Xu
Published: March 2009

In order to improve non‐uniform radial and axial flow structure of a circulating fluidized bed, the influence of ring‐type internals on the axial pressure distribution and gas—solids flow structure in a riser of 7.6 cm in diameter and 3 m in height was investigated experimentally. Four different opening areas, 70%, 80%, 90% and 95%, were used and the superficial gas velocity and solids circulation rate were in the ranges of 5 to 10 m/s and 20 to 233 kg/m2·s, respectively. With the presence of internals, the axial pressure gradient distribution shows the formation of a zigzag type profile instead of the regular exponential or S‐shape profile and the bottom acceleration region is shortened. The opening ratio of the rings plays an important role in affecting the flow structure. The optimal opening ratio is tightly related to the operating conditions. In the circulation fluidized bed used in this study, 90% open area was found to be most suitable for obtaining a more uniform gas—solids flow structure.
Effects of sparger height and orifice orientation on solids dispersion in a slurry bubble column
Authors: Gandhi Bimal , Prakash Anand , Bergougnou Maurice A.
Published: March 2009

The effects of gas distributor height and the orientation of its orifices are investigated on solids dispersion and gas holdup profiles in a three‐phase slurry bubble column. The height of the distributor was varied to cover locations from near column bottom to above the settled solids bed height. The orifice orientations were changed from upward facing to downwards facing directions. The measurements were conducted in a Plexiglas column of 0.15 m ID and 2.5 m height. The gas phase was oil‐free compressed air while tap water was used as liquid phase. Glass beads with an average particle diameter of 35 μm and density of 2450 kg/m3 constituted the solid phase. The settled bed height was about 0.4 m which provided an average slurry concentration of about 15% (v/v) when all solids were dispersed. Both axial and column average phase holdups were measured. Effects of sparger location, gas jets formation and liquid circulation patterns on gas holdups and solids dispersion are analyzed. Empirical correlations are developed to relate sparger location to solids dispersion as a function of gas velocity. Optimum sparger height and orifice orientation is proposed based on the measurement of this study.
Dynamic modeling of continuous evaporative cooling KCl‐NaCl crystallizers
Authors: Tadayyon Abdulsamad , Rohani Sohrab
Published: March 2009

Previous work on the modeling of potash crystallizers has been mainly limited to the estimation of crystal size distribution (CSD) in the presence of only one solid component (KCl). In the present study, an attempt has been made to develop a model that incorporates NaCl as a second component that may co‐precipitate along with KCl under certain operating conditions. Addition of water to prevent co‐saturation or as a means of internal fines dissolution is also taken into consideration. External fines dissolution using a heat exchanger is incorporated in the model. In addition to the CSD, the model is able to predict crystal impurity resulting from co‐saturation with NaCl. The predictive capability of the model is tested using limited dynamic experimental data obtained from a 1 m3 pilot plant continuous evaporative crystallizer and the steady‐state experimental data from a two‐stage evaporative Swenson DTB industrial potash crystallizer circuit. In both cases, a good agreement between the model predictions and the experimental data was noticed.
Coprecipitation of CaCO3 and CaSO4
Authors: Sudmalis Michael , Sheikholeslami Roya
Published: March 2009

Coprecipitation characteristics of CaCO3 and CaSO4 were studied under various operating conditions. The investigations were carried out in temperature‐controlled batch tests. Coprecipitation results were compared with our experimental results of a single salt crystallization. It was found that the induction period and kinetics of coprecipitation of these two salts follow that of pure CaCO3. However, thermodynamic concentrations of Ca in coprecipitation followed that of pure CaSO4 at all times. The relationship between the thermodynamic concentrations of Ca for pure CaCO3 and CaSO4 solutions depended on the pH of the CaCO3 solution. CaSO4 precipitated in form of gypsum and had a needle shape structure; CaCO3 had a spiral growth and precipitated in form of calcite. The precipitate structure was affected by the co‐existence of salts; the co‐precipitation resulted in CaCO3 crystals interwoven by CaSO4 crystals. This tends to result in a co‐precipitate that is stronger than pure CaSO4 and weaker than pure CaCO3 precipitate.
Gas spouting hydrodynamics of fine particles
Authors: Wang Shining , Xu Jian , Wei Weisheng , Shi Gang , Bao Xiaojun , Bi H. T. , Lim C. Jim
Published: March 2009

Hydrodynamic measurements for the spouting of fine particles were obtained in a conical‐based cylindrical bed of diameter 0.186 m, inlet orifice diameters of 6 to 14 mm, and included cone angles of 45 to 80 degrees. Four different types of fine particles with diameters ranging from 0.286 to 0.861 mm were investigated. Four different flow regimes—fixed bed, stable spouting, unstable spouting and slugging—were identified and mapped. The termination of the spouting of fine particles was caused by choking rather than by fluidization of particles in the upper bed. Stable spouting could be achieved when the ratio of the orifice diameter to mean particle diameter was less than 20. The measured minimum spouting velocities were within ±15% of those predicted by the Mathur—Gishler equation. Solids density measurements obtained by a gamma ray densitometer showed that the solid density in the spout increases with bed height and in the annulus is 3% to 10% higher than in a loosely packed bed.
Transient analysis of gas flow in a straight pipe
Authors: Hati Anindya , Verma Nishith , Chhabra Raj
Published: March 2009

In the present work, numerical simulation has been done to analyze transients in gas flow and pressure in a horizontal straight pipe. For a single gas pipeline, eight representative cases corresponding to different causes of transient behaviour are simulated to predict unsteady state flow and the evolution of pressure profiles. The numerical results show that depending upon the pipe dimensions and operating variables such as pressure and gas flow rate, transient effects in the pipeline may last for a long time and/or over significant length of pipe. The simulations predict an initial surge in gas flow rate greater than the final steady‐state value if the pressure drop across the pipe is increased. Similarly, initial flow rate may decrease below the final steady‐state value if the pressure drop is decreased. In case of complete closure of a valve, oscillations in both pressure and mass flow rate are observed, which gradually decay and the steady state conditions of no flow are ultimately achieved. The present results are compared with a published work from the literature. A reasonably good agreement is found between these two predictions. The present study is of practical significance in safe design and operation of a gas delivery system.
Strength development due to long term sulfation and carbonation/sulfation phenomena
Authors: Anthony Edward J. , Jia Lufei , Laursen Karin
Published: March 2009

CFBC boilers firing high sulfur, low ash fuels can produce deposits consisting of almost pure CaSO4. Test work has shown that if sorbents or bed materials are sulfated for long times (several days or more), they develop compositions similar to those deposits. Sulfation increases with temperature from 650°;C to 900°C, and strength increases continuously in the temperature range of 650°C to 950°C. When sulfation occurs under conditions where CaCO3 is stable, the overall strength of the deposit increases but the degree of sulfation diminishes. Finally, this work suggests that pellet tests using crushed and calcined sorbents can give misleading information and should be used with caution to study the phenomena described here.
Effect of temperature and concentration in catalytic deactivation of a parallel (competitive) reaction system: Application to hydrotreating of vacuum gas oil
Authors: Bruzzanese Adriana , Galiasso Roberto
Published: March 2009

The temperature‐time sequences to maintain constant the concentration of one product in a two‐parallel (competitive) exothermic reaction system undergoing catalyst deactivation are analyzed. Kinetics is described by a power law model and linear particle deactivation. A computational algorithm and a parametric study for adiabatic packed bed reactors are presented. It is found that temperature‐time trajectories are strongly influenced by mean activity, and the selectivity. Experimental information for Hydrotreating of vacuum gas oil was obtained keeping constant desulfurization, while hydrocracking and denitrogenation are function of time. Trajectories and final operating temperature are predicted with error below 2% compared to real operation.
Transition velocities and phase holdups at minimum fluidization in gas–liquid–solid systems
Authors: Lee Donghyun , Macchi Arturo , Epstein Norman , Grace John R.
Published: March 2009

Hydrodynamic experiments were performed using a 127‐mm diameter column with 3.2‐mm porous alumina, 3.3‐mm polymer blend, 5.5‐mm polystyrene and 6.0‐mm glass spheres, with water, aqueous glycerol solution and silicone oil as liquids, and air as the gas. The voidage at minimum fluidization fell initially to a minimum, then rose gradually with increasing superficial gas velocity, and was lower for three‐phase systems than for corresponding two‐phase (liquid–solid) fluidized beds. The compaction appears to be due to agitation by gas bubbles near the minimum liquid fluidization condition. The gas holdups agree reasonably well with the correlation of Yang et al. (1993). Curves of minimum liquid fluidization velocity, Ulmf, vs. superficial gas velocity, Ug always show Ulmf decreasing as Ug increases, initially in a concave‐downward manner, but sometimes concave‐upward.
Relationship between the colloidal and rheological properties of mineral suspensions
Authors: Cerpa Arisbel , García‐González Maria T. , Serna Carlos J. , Tartaj Pedro
Published: March 2009

The electrokinetic and rheological behaviour of lateritic aqueous suspensions has been analyzed as a function of samples chemical composition, pH of suspensions, and nature and concentration of electrolyte added to the aqueous suspensions. First, it was determined that the isoelectric point (IEP) of suspensions in the presence of non‐adsorbing electrolytes is a function of the ratio serpentine/ goethite present in samples. The flow properties of the suspensions are strongly dependent on pH, reaching the highest values of apparent viscosity at values around the isoelectric point. Specific adsorption of silicate and magnesium species on particles surface was revealed by a shift in the IEP. In particular, silicate anions shifted the IEP value to acidic pH whilst magnesium cations shifted the value to basic pH. A similar trend was displayed in the rheological behaviour of suspensions where the highest viscosity values were shifted to the same direction.
Trickle‐bed scrubbing of flue gas SO2 using non‐aqueous solvents
Authors: Panthaky Mahiyar A. , Vladeas Radu V. , Lohi Ali , Hudgins Robert R. , Silveston Peter L.
Published: March 2009

Experiments were carried out on the performance of several ketone solvents for the scrubbing of dilute SO2 from a gas stream and its conversion to sulfuric acid in a trickle‐bed reactor packed with activated carbon. Using a bench‐scale trickle bed packed with a structured packing based on Sulzer static mixers coated with CentaurTM activated carbon and a Teflon binder, measurements of SO2 removal, conversion to acid and catalyst productivity showed that all were considerably greater than levels achieved with water flushing. The combination of Teflon‐coated Centaur activated carbon with a non‐aqueous solvent as the flushing agent provided from 10 to 100 times higher catalyst productivity than those obtained with water alone and other activated carbons. Also, the productivities obtained by this combination were up to 40 times higher than the productivity of typical vanadium pentoxide catalyst operating at 350°C to 400°C.
Measurement and correlation of the activity coefficients of individual ions in aqueous electrolyte solutions of Na2So4 and K2So4
Authors: Rodil Eva , Vera Juan H.
Published: March 2009

Ion selective electrodes have been used to measure the activity coefficients at 298.2 K of individual Na+ions in aqueous solutions of Na2SO4 up to 3 molal, and of individual K+ ions in aqueous solutions of K2SO4 up to 0.69 molal. The activity coefficients of the sulfate anion were calculated using values of the mean ionic activity coefficients of the salts. Contrary to the behavior found in 1:1 electrolyte aqueous solutions, the activity coefficients of both cations have been found to be larger than the activity coefficient of the sulfate anion. A model proposed by Khoshkbarchi and Vera was used to correlate the data and model parameters are reported.
Periodic behaviour of a class of unstructured kinetic models for continuous bioreactors
Authors: Ajbar Abdelhamid
Published: March 2009

The periodic behaviour of a large dass of unstructured kinetic models for continuous bioreactors is analyzed using elementary concepts of singularity theory and continuation techniques. The class consists of models for which the utilization rate of the limiting substrate is linearly related to the rates of cell growth and product formation. The model kinetics are allowed, on the other hand, to depend on substrate, biomass and product. The stability analysis allows the derivation of general analytical conditions for the occurrence of periodic behaviour in these models. It is shown that for a number of important cases, the occurrence of oscillatory behaviour is conditioned mainly by the kinetics of product formation. The singularity theory also allows the construction of a useful picture in the multidimensional parameter space delineating the different behaviour these models can predict including bistability and stable oscillatory behaviour.
Multi‐controller scheme for load rejection and set‐point tracking
Authors: Guo Bingjun , Jutan Arthur
Published: March 2009

To acheive complete compensation for loads, a novel multi‐controller scheme with feedforward control is proposed. This scheme has four controllers, a set‐point controller, two load controllers, and a feedforward controller. This results in the separation of the load response from the set‐point response in a closed‐loop system. These four controllers can then be designed independently to achieve good system performance for both set‐point tracking and load rejection. One of the load controllers can be chosen as a proportional controller; this guarantees physical realizability and provides excellent compensation. The results of simulation and real time control show that the proposed multi‐controller scheme is superior to a double‐controller system and a Smith predictor in the presence of large uncertainty in process dynamics especially for load disturbances.
Photolysis of o‐Nitrobenzaldehyde in the Gas Phase: A New OH. Formation Channel
Authors: Cheng Shi‐Bo , Zhou Can‐Hua , Yin Hong‐Ming , Sun Ju‐Long , Han Ke‐Li
Published: March 2009

New route to gas‐phase OH.: UV photolysis of gaseous o‐nitrobenzaldehyde forms OH radicals via the transformation into the ketene or o‐nitrosobenzoic acid intermediate (see figure). The OH. product is monitored by single‐photon laser‐induced fluorescence (LIF).

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Photolysis of gaseous o‐nitrobenzaldehyde (o‐NBA) with selected different excitation wavelengths (355‐400 nm) is investigated, and the nascent OH radical is detected by the single‐photon laser‐induced fluorescence (LIF) technique. The relative quantum yield and rotational excitation of OH formation are found to be dependent on the excitation energy. The distributions of rotational, spin–orbit, and Λ‐doublet states are obtained at 355–400 nm by analyzing the experimental data. The OH radicals are found to be vibrationally cold at all photolysis wavelengths. The spin–orbit and Λ‐doublet states have nonstatistical distributions. To understand the dissociative process involved in the OH‐generating channel, DFT calculations are performed. Based on both experimental and theoretical results, possible photolysis channels of o‐NBA leading to the OH fragment are proposed and discussed.
Miscibility and Alignment Effects of Mixed Monolayer Cyanobiphenyl Liquid‐Crystal‐Capped Gold Nanoparticles in Nematic Cyanobiphenyl Liquid Crystal Hosts
Authors: Qi Hao , Kinkead Brandy , Marx Vanessa M. , Zhang Huai R. , Hegmann Torsten
Published: March 2009

Against the rule: Liquid crystal hosts (5CB and 8CB) are doped with different thiol decorated gold nanoparticles (see figure). The “simple” hexanethiol and dodecanethiol capped nanoparticles (Au1 and Au2) are more compatible to the nematic cyanobiphenyl liquid crystals than nanoparticles capped simultaneously with alkylthiols and a nematic cyanobiphenyl thiol (Au3 and Au4).

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This study focuses on the miscibility of liquid crystal (LC) decorated gold nanoparticles (NPs) in nematic LCs. To explore if LC functional groups on the gold NP corona improve the compatibility (miscibility) with structurally related LC hosts, we examined mixtures of two LC hosts, 5CB and 8CB, doped at 5 wt % with different types of gold NPs. Four alkanethiol‐capped NPs were synthesized; two homogeneously coated with alkanethiols (Au1 with C6H13SH and Au2 with C12H25SH), and two that were additionally capped at a different ratio with a mesogenic cyanobiphenyl end‐functionalized alkanethiol HS10OCB (C6H13SH + HS10OCB for Au3 and C12H25SH + HS10OCB for Au4). Investigating these mixtures in the bulk for settling of the NPs, and in thin films using polarized optical microscopy (POM) between untreated glass slides as well as POM studies and electro‐optic tests in planar ITO/polyimide test cells, reveal that the alkanethiol capped NPs Au1 and Au2 are more compatible with the two polar cyanobiphenyl hosts in comparison to the NPs decorated with the cyanobiphenyl moieties. All NPs induce homeotropic alignment in 5CB and 8CB between untreated glass slides, with Au1 and Au2 showing characteristic birefringent stripes, and Au3 and A4 exhibiting clear signs of aggregation. In rubbed polyimide cells, however, Au3 and Au4 fail to induce homeotropic alignment and show clear signs of macroscopic aggregation.
Aqueous Networks and Toroids of Amphiphilic Block Copolymer with Non‐ionic Surfactants
Authors: Fu Jun , Kim Dong Ha , Knoll Wolfgang
Published: March 2009

Network formation: Comicellization of polystyrene‐block‐polyethylene oxide (PS–PEO) with non‐ionic surfactants leads to the formation of networks and chains of spheres. The aqueous network solutions are responsive to dilution, undergoing morphological transformations to cylinders with Y junctions and both two‐ and three‐dimensional toroids (see figure).

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Three‐dimensional visualization of testis cord morphogenesis, a novel tubulogenic mechanism in development
Authors: Combes Alexander N. , Lesieur Emmanuelle , Harley Vincent R. , Sinclair Andrew H. , Little Melissa H. , Wilhelm Dagmar , Koopman Peter
Published: March 2009

Testis cords are specialized tubes essential for generation and export of sperm, yet the mechanisms directing their formation, and the regulation of their position, size, shape, and number remain unclear. Here, we use a novel fluorescence‐based three‐dimensional modeling approach to show that cords initially form as a network of irregular cell clusters that are subsequently remodeled to form regular parallel loops, joined by a flattened plexus at the mesonephric side. Variation in cord number and structure demonstrates that cord specification is not stereotypic, although cord alignment and diameter becomes relatively consistent, implicating compensatory growth mechanisms. Branched, fused, and internalized cords were commonly observed. We conclude that the tubule‐like structure of testis cords arise through a novel form of morphogenesis consisting of coalescence, partitioning, and remodeling. The methods we describe are applicable to investigating defects in testis cord development in mouse models, and more broadly, studying morphogenesis of other tissues. Developmental Dynamics 238:1033–1041, 2009. © 2009 Wiley‐Liss, Inc.
Peripheral Functionalization of Subphthalocyanines (Eur. J. Org. Chem. 12/2009)
Authors: González‐Rodríguez David , Torres Tomás
Published: March 2009

The cover picture shows new members of the subphthalocyanine family that were obtained by peripheral derivatization of this C3‐symmetrical macrocycle. The incorporation of novel functionalities onto these dyes provides wider versatility that could be exploited in artificial photosynthetic systems and other applied fields. Details are discussed in the article by D. González‐Rodríguez and T. Torres on p. 1871 ff.
Involvement of fractin in TGF‐β‐induced apoptosis in oligodendroglial progenitor cells
Authors: Schulz Ramona , Vogel Tanja , Mashima Tetsuo , Tsuruo Takashi , Krieglstein Kerstin
Published: March 2009

Transforming growth factor‐β (TGF‐β) induces apoptotic cell death during the development of the nervous system. We recently identified that TGF‐β induced apoptosis in oligodendroglial progenitor cells (primary cells as well as oligodendroglial cell line OLI‐neu) is characterized by down‐regulation of Bcl‐xl. In this report, we now focused on mechanisms that mediate TGF‐β dependent Bcl‐xl down‐regulation in oligodendroglial cells. We showed that the caspase‐specific cleavage product Fractin is produced in oligodendroglial cells during TGF‐β‐mediated apoptosis, which represents an early event of the cascade. Cleavage of actin into Fractin was dependent on functional actin and caspases, and occurred simultaneously with a Fractin‐Bcl‐xl‐interaction. This Fractin‐Bcl‐xl interaction indicated a connection between Bcl‐xl down‐regulation and Fractin appearance, since Bcl‐xl regulation was also dependent on caspases and functional actin, and an overexpression of Fractin induced a Bcl‐xl protein down‐regulation. Further analysis of Fractin‐Bcl‐xl interaction in other culture systems confirmed these data. In conclusion, we show that Fractin is not only an apoptotic marker, but has indeed a functional role in apoptotic signaling in oligodendrocytes. © 2009 Wiley‐Liss, Inc.
Towards the Quantitative Prediction of the Phase Behavior of Polymer Solutions by Computer Simulation
Authors: Binder Kurt , Mognetti Bortolo Matteo , Macdowell Luis Gonzalez , Oettel Martin , Paul Wolfgang , Virnau Peter , Yelash Leonid
Published: March 2009

The phase diagram of polymer solutions (cf. e.g. alkanes dissolved in supercritical carbon dioxide) is complicated, since there are four control parameters (temperature, pressure, monomer volume fraction, chain length of the polymer) and due to the interplay of liquid‐vapor transitions and fluid‐fluid unmixing. As a result very intricate phase diagram topologies can result. An attempt to develop coarse‐grained models that can deal with this task will be described. As usual, the polymers will be modelled as off‐lattice bead‐spring chains, where several chemical monomers are integrated into one effective bond, torsional degrees of freedom being disregarded. But also a coarse‐grained description of the solvent is needed: we show that using a simple point particle with a quadrupole moment and suitable Lennard‐Jones interaction yields a very good description of pure carbon dioxide (better than fully atomistic models with potentials from ab initio quantum chemistry calculations). The strength of the quadrupole moment is taken from experiment, and the Lennard‐Jones parameters are adjusted such that the experimental critical temperature and density is correctly reproduced. This procedure works for other solvents as well, such as benzene. The pure alkane phase diagram is also reproduced by similarly chosen Lennard‐Jones (LJ) potentials among the monomers, and the monomer‐carbon dioxide LJ parameters are chosen from Lorentz‐Berthelot mixing rules. These parameters are then used as input both for Monte Carlo calculations and approximate methods to calculate the equation of state, such as density functional and perturbation theory methods. Apart from the region close to critical points, where mean‐field type methods fail, the analytical calculations agree well with the simulations. The solvent model, in which quadrupolar interactions are explicitly considered, is important in order to obtain a fair agreement with mixture experimental results.
A constant rounds group key agreement protocol without using hash functions
Authors: Zhang Hua , Wen Qiao‐yan , Zhang Jie , Li Wen‐min
Published: March 2009

It is important to encrypt and authenticate messages sent over networks to achieve security. Network users must therefore agree upon encryption keys and authentication keys. The authenticated Diffie–Hellman key agreement protocol is used to provide authentication in communication systems. In this paper we present a group key agreement protocol without using one‐way hash functions that are based on the DDH problem. The protocol achieves efficiency in both communication and computation aspects. We analyzed the security in the security model formalized by Bresson et al. Copyright © 2009 John Wiley & Sons, Ltd.
Optimization of electrode configuration in large GaInN light‐emitting diodes
Authors: Ochiai Wataru , Kawai Ryosuke , Suzuki Atsushi , Iwaya Motoaki , Amano Hiroshi , Kamiyama Satoshi , Akasaki Isamu
Published: March 2009

Flip‐chip 1×1 mm2 GaInN‐based light‐emitting diodes (LEDs) with an interdigitated electrode design were investigated. Two types of GaInN‐based LED having a 4‐line p‐electrode with a width of 160 μm and an 8‐line p‐electrode with a width of 50 μm were fabricated. The 8‐line device with a 50‐μm‐wide p‐electrode shows 20% higher output power at a forward current of 350 mA than the 4‐line device with a 160‐μm‐wide p‐electrode. The three dimensional simulation of the LED operation was conducted to clarify the origin of the difference in output power. From simulation results, the output power of the device with a 50‐μm‐wide 8‐line p‐electrode was estimated to be 10% higher than that of the device with a 160‐μm‐wide 4‐line p‐electrode. A large difference in current density between the middle and edge of each 160‐μm‐wide electrode is suggested. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
National corporate governance institutions and post‐acquisition target reorganization
Authors: Capron Laurence , Guillén Mauro
Published: March 2009

We examine the characteristics of national systems of corporate governance to theorize about the nature of the shareholders' and employees' interests when it comes to reorganization, under the assumption that the firm is coalitional in nature. We argue that corporate governance institutions prevalent in both the host and the target country of the merging firms enable or constrain the ability of the acquirer to reorganize the target. Using a cross‐national dataset of corporate acquisitions and post‐acquisition reorganization, we found support for our predictions that stronger legal protection of shareholder rights in the acquirer country compared to the target country increases the acquirer's ability to restructure the target's assets and leverage the target's resources, while the protection of employee rights in the target country restricts the acquirer's ability to restructure the target's assets and redeploy resources to and from the target. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of a robust and energy efficient transmission scheduling protocol in single‐hop ad hoc networks
Authors: Jun Junghyon , Choi Young‐June , Bahk Saewoong
Published: March 2009

A fully connected one‐hop ad hoc network constitutes a basic unit for managing self‐organizing networks such as IEEE 802.11 and 802.15.3 networks. Since energy efficiency is a critical issue in ad hoc networks, we develop an energy‐saving framework that includes scheduling for node‐to‐node direct communication. The scheduling is performed by a coordinator that is selected by some simple rule. We enhance IEEE 802.11 protocol by using our proposed framework, and analyze its energy efficiency in transmitting and receiving data. Through mathematical analysis, we confirm that our enhanced protocol significantly saves energy compared to the IEEE 802.11 protocol. We also investigate the robustness of our algorithm by covering the cases of uncooperative users, system malfunctioning, and channel errors. The numerical results confirm that our protocol works well under these hostile environments and maintains its advantage over the conventional scheme. Copyright © 2009 John Wiley & Sons, Ltd.
The story of a cold pool
Authors: Prichard Bob
Published: March 2009

Much of southern Britain recorded its heaviest snowfall for many years during the first week of February 2009. This Weather Image briefly describes how a cold pool was responsible for much of the snow, and tracks its movement.
On strategy of the upcoming exploration phase in the North Caspian petroleum province
Authors: Volozh Yu.A. , Dmitrievskii A.N. , Leonov Yu.G. , Miletenko N.V. , Rovnin L.I.
Published: March 2009

This paper gives a review of oil and gas resource potential of the North Caspian petroleum province. A new potential for finding several giants and large-size discoveries exists, respectively, in the presalt and postsalt sequences. Recommendations for future directions in exploration targeting at postsalt deposits (Upper Permian–Triassic and Jurassic–Paleogene petroleum systems) are given. It is emphasized that, given adequate exploration techniques, the postsalt sequence may provide stable and commercial production for decades. Most of the prospects are located within nonlicensed area. Therefore, the future exploration activity will have to be implemented through special-purpose governmental projects, namely, state-funded integrated projects aiming at investigation of the individual petroleum regions and zones.
Urgent issues in replenishment of hydrocarbon mineral and raw materials base in present-day Russia
Authors: Prischepa O.M.
Published: March 2009

The article deals with current problems of exploitation and pre-exploitation measures in oil and gas resource replenishment in Russia. Specific procedures are proposed to be taken at different levels of state administration for improving the efficiency of reserves replenishment. The public private partnership is suggested as one of the effective means to solve the problem. The level of the state’s involvement in funding and management during regional exploration and prospecting survey is discussed. A systemic approach and a set of criteria for assessing the exploration success rate (at different stages) are recommended for use by the state, as subsurface owner, and for operating companies. In addition, several recommendations and action-oriented proposals are given for preparation of licensing programs that will ensure the preset rates of oil and gas reserves replenishment in the region.
Oxidation in Soils, and its connexion with Fertility.
Authors: Russell Edward J.
Published: March 2009

The phenomena attending the absorption of oxygen by soils have been investigated by Déherain and Demoussy, and also by Wollny. An account of the work of the French chemists can be found in the Annales Agronomiques. Their method was to place the soils under examination in a closed tube holding about 100 c.c. and kept at constant temperature, then after a certain time to extract the gases and determine the carbon dioxide present. This was taken to be a measure of the amount of oxidation. The general results they obtained are as follows:

1. The quantity of carbon dioxide produced increases with the temperature to about 65°C., and then decreases. At higher temperatures (above 90°) it increases again.