bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinear Real‐time Process Monitoring and Fault Diagnosis Based on Principal Component Analysis and Kernel Fisher Discriminant Analysis
Authors: Zhang X. , Yan W.‐W. , Zhao X. , Shao H.‐H. 
Published: August 2007

AbstractThe aim of this paper is to propose a novel real‐time process monitoring and fault diagnosis method based on the principal component analysis (PCA) and kernel Fisher discriminant analysis (KFDA). There is a need to develop this method in order to overcome the inherent limitations of the current kernel FDA method. The idea of the method is to initially reduce dimensionality using PCA and then to map the score data in the reduced original space to the high‐dimensional feature space via a nonlinear kernel function. Following this, the optimal Fisher feature vector and discriminant vector are extracted to perform process monitoring. If faults occur, the method uses the degree of similarity between the optimal discriminant vector presented and the optimal discriminant vector of the faults in the historical dataset to perform a diagnosis. The proposed method can effectively capture nonlinear relationships in process variables. In comparison with kernel FDA, the PCA plus kernel FDA method is more efficient and has a more rapid response when used to undertake online monitoring and fault diagnosis. In this study, the method is evaluated by applying it to the fluid catalytic cracking unit (FCCU) process. As a consequence, its effectiveness is demonstrated.
An Electrospray Method Using a Multi‐Capillary Nozzle Emitter
Authors: Tatemoto Y. , Ishikawa R. , Takeuchi M. , Takeshita T. , Noda K. , Okazaki T. 
Published: August 2007

AbstractA multi‐capillary nozzle emitter consisting of one metal plate with capillary nozzles and a ring type counter electrode was used as a multi‐electrospray atomizer. The number of capillary nozzles, flow rate of the liquid and the interval between the capillary nozzles were changed, and the droplet diameter and the voltage required for a steady cone‐jet mode were measured. For the multi‐capillary nozzle emitter, the interaction between the capillary nozzles is the important factor for obtaining fine droplets of uniform size. These fine droplets are obtained when there is only a small interaction between the capillary nozzles, and the equations obtained from the single capillary nozzle case are also applicable for the multi‐capillary nozzle emitter. When the number of capillary nozzles decreases (a situation which is not good for obtaining a large amount of droplets) or the interval between the capillary nozzles increases, the interaction between the capillary nozzles can be reduced. As the number of capillary nozzles increase, a higher voltage is required to obtain a fine droplet of uniform size.
Emulsion Liquid Membrane Pertraction of Zinc and Copper: Analysis of Emulsion Formation using Computational Fluid Dynamics
Authors: Ganesh Prasadh K. , Venkatesan S. , Meera Sheriffa Begum K. M. , Anantharaman N. 
Published: August 2007

AbstractThis work reports on a study of batch extraction of metal ions (copper and zinc) from dilute aqueous solutions as well as recovery of copper from electroplating waste water by the emulsion liquid membrane (ELM) technique. Several experiments were conducted to assess the effect of membrane composition on metal recovery. The effect of surfactant concentration, carrier concentration, and emulsification time on the emulsion stability has been reported. The velocity profile and flow model of the two‐phase mixing system during the preparation of the emulsion was generated using computational fluid dynamics (CFD). The batch extraction was carried out under various experimental conditions, such as agitation speed, M/E ratio, solute concentration in the feed phase, and carrier concentration in the membrane phase on the percentage recovery of zinc and copper ions in their respective feed streams. The operating parameters were optimized for maximum recovery. A comparison on the percentage recovery was made between synthetic solution and electroplating effluent containing copper ions.
CFD Simulation of Gas Distribution Performance of Gas Inlet Systems in Packed Columns
Authors: Haghshenasfard M. , Zivdar M. , Rahimi R. , Nasr Esfahany M. 
Published: August 2007

AbstractPacked columns are widely used in the chemical process industries. The optimum operation of these columns requires an even distribution of gas and liquid flows. This paper describes a method for modeling the flow pattern which develops above the gas inlet system using a computational fluid dynamics (CFD) approach. The uniformity of the gas flow through the packing is assessed by means of a maldistribution factor, MF. Several factors which affect gas distribution, such as gas inlet type, gas inlet diameter and the distance between gas inlet and column bottom, were analyzed. It was found that gas distribution is more uniform as the inlet diameter and bottom distance are increased. Comparison of experimental data with a CFD simulation for several types of gas inlets, such as straight, slope and bend inlets, shows good agreement.
Loading Dependence of Self‐Diffusivities of Gases in Zeolites
Authors: Krishna R. , van Baten J. M. 
Published: August 2007

AbstractExperimental data on the self‐diffusivities, Di,self, of a variety of gases (CH4, N2, Kr, C2H6, and C3H8) in three different zeolites, LTA, FAU, and MFI, show different dependences on the molar loading, qi. In LTA, Di,self appears to increase with qi for all molecules except N2. In FAU and in MFI the Di,self shows a sharp decrease with increasing qi. In order to gain insights into the causes behind the loading dependences, molecular dynamics (MD) simulations were carried out to determine the self‐diffusivities of seven gases (CH4, N2, Kr, C2H6, C3H8, Ar, and Ne) in six different all‐silica zeolite structures (MFI, AFI, FAU, CHA, DDR, and LTA). The simulation results show that the variation of Di,self with qi is determined by a variety of factors that include molecular size and shape, and degree of confinement within the zeolite. For one‐dimensional channels (AFI) and intersecting channel structures (MFI), the Di,self invariably decreases with increasing qi. For zeolite structures that consist of cages separated by windows (FAU, CHA, DDR, LTA), the size of the windows is an important determinant. When the windows are wide (FAU), the Di,self decreases with qi for all molecules. If the windows are narrow (CHA, DDR and LTA), the Di,self often exhibits a sharp increase with qi, reaches a maximum and reduces to near‐zero values at saturation. The sharpness with which Di,self increases with qi, is dictated by the degree of confinement at the window. Weakly confined molecules, such as Ne, do not exhibit an increase of Di,self with qi.
Kinetics of SO2Removal from Flue Gas on CuO/Al2O3Sorbent Catalyst
Authors: Jia Z. H. , Liu Z. Y. , Zhao Y. H. 
Published: August 2007

AbstractThe dependence of SO2removal on Cu loading, SO2concentration, and temperature are studied experimentally on a thermo‐balance using a series of CuO/Al2O3catalysts in the fresh state as well as in a NH3‐regenerated state. A kinetic study on SO2removal is then carried out using a surface model, which assumes the SO2removal rate is being controlled by a surface chemical reaction and takes into account the effect of SO2adsorption and consumption of surface CuO. The difference in SO2removal between fresh and regenerated CuO/Al2O3is expressed by a parametern, which is similar to the order of a reaction. The effect of SO2adsorption is expressed in the Langmuir‐Hinshelwood form. The results show that the SO2removal behavior of NH3‐regenerated CuO/Al2O3is different from that of fresh CuO/Al2O3and the developed model describes the SO2removal behavior well.
Isoconversional Kinetic Analysis of Isothermal Selective Ethanol Adsorption on Zeolite Type NaZSM‐5
Authors: Adnadevic B. , Mojovic Z. , Abu Rabi A. , Jovanovic J. 
Published: August 2007

AbstractThe kinetic parameters of the selective isothermal adsorption of ethanol from an aqueous solution onto a hydrophobic zeolite type NaZSM‐5 were determined using a series of the so‐called standard methods (the initial rate, the saturation rate and the maximum rate methods). The kinetic model of ethanol adsorption was determined by the “model fitting” method. The dependence of the kinetic parameters on the degree of adsorption and the presence of a compensation effect were determined by the isoconversional method. The complex changes of the activation energy and pre‐exponential factor with the degree of adsorption were explained by the model of the activation energy distribution of elemental adsorption processes.
Coal to Liquid (CTL): Commercialization Prospects in China
Authors: Hao X. , Dong G. , Yang Y. , Xu Y. , Li Y. 
Published: August 2007

AbstractProduction of fuels/chemicals from syngas (CO + H2) is receiving increased attention with the background of the resource depletion and the unstable prices of petroleum oil. The fuels, especially diesel, obtained from the syngas conversion via Fischer‐Tropsch synthesis (FTS), are proved to be of very high quality that will contribute much to environmental protection and raising the energy efficiency in the transportation sector when modern diesel engines are massively applied in vehicles. FTS technologies developed in recent years have reached the stage for the feasibility of construction of large‐scale complexes. Under a long‐term consideration of developing the field of coal to liquids (CTL), major issues in successfully applying CTL technologies are those controlling the feasibility of all kinds of projects. Points identified are, in general: (1) efficiency advantage over conventional processes (e.g. thermal power generation process); (2) cost and economic benefit; (3) environment advantage. These questions have been better answered using CTL‐based poly‐generation schemes. Among all the different schemes, in principle, the co‐production of liquid fuels and electricity are naturally the main frame. The simple efficiency increase due to the better energy balance in the co‐production mode and the environment protection advantage due to the easy‐to‐apply technology in the pollutant removal and treatment from syngas in a liquid fuel process has projected a bright future even for applying the more capital intensive IGCC + F‐T scheme, which can raise the efficiency (to end products) from 43–46 % in either single schemes to about 52–60 %. This new process will guarantee a better solution to environment protection.
Distillation Tower with Distributed Control Strategy: Feed Temperature Loads
Authors: Marangoni C. , Machado R. A. F. 
Published: August 2007

AbstractDistillation towers require control systems adjusted to rapidly reject loads. Temperature control of these units is normally carried out at the bottom and top of the column, increasing the tower response time. In this paper, a change in this temperature control configuration is proposed through the introduction of heating points distributed among the trays throughout the column. The proposed strategy was tested in an experimental unit with an ethanol‐water mixture applying a conventional approach (control at bottom and top only) and the proposed distributed configuration (bottom, top and tower trays) with feed temperature disturbance. The results showed a significant reduction in the time required for the column to stabilize after the load introduction, compared with the conventional approach, making faster dynamics possible.
Nanofiltration Membrane Process for the Removal of Arsenic from Drinking Water
Authors: Uddin M. T. , Mozumder M. S. I. , Islam M. A. , Deowan S. A. , Hoinkis J. 
Published: August 2007

AbstractThe removal of arsenic from drinking water by nanofiltration membranes was investigated. Experiments were conducted with tap water to which arsenate and arsenite were added. Two types of nanofiltration membranes, i.e., NF‐90 and NF‐200, have been tested. The effect of various operating conditions, e.g., applied pressure, feed concentration, pH and temperature, were also investigated. The pH and arsenic concentration in the feed and the operating temperature are found to be decisive factors in determining the arsenic concentration remaining in the permeate. The level of removal of As(V) was higher than 98 % for both membranes, but that of As(III) was much lower. It can be concluded that by controlling the operating parameters, source water containing As(V) may be recovered as drinking water to EPA maximum contaminant level quality standards, but that water containing As(III) must undergo a pre‐oxidation treatment before passing through the nanofiltration membrane in order to maintain drinking water quality.
Electrocatalytic Oxidation of Glucose on Gold Nanocomposite Electrodes
Authors: Jin C.‐C. , Taniguchi I. 
Published: August 2007

AbstractThe electrocatalytic oxidation of glucose on gold nanocomposite electrodes was investigated with cyclic voltammetry. The gold nanocomposite electrodes were prepared by precipitating gold nanoparticles of different sizes from the corresponding colloidal solutions onto planar substrates, and the electrodes exhibited higher catalytic activity for the oxidation of glucose in alkaline solution with a negative shift in oxidation potential and a larger current as compared with bare gold electrodes. The high catalytic activity of the gold nanocomposite electrodes also resulted in easy oxidation of gluconolactone produced in the reaction. The modification of the gold nanocomposite electrodes with silver underpotential deposition led to a further negative shift in potential but a drop in current for the glucose oxidation.
A Method for the Design of Divided Wall Columns
Authors: Sotudeh N. , Hashemi Shahraki B. 
Published: August 2007

AbstractA divided wall column has been modeled as a Petlyuk column with no heat transfer across the column wall. The feed to the column has been generalized as a mixture of saturated liquid and vapor (0 <q<1). The pinch compositions at connection points, the Fenske equation and the Gilliland correlations, which have been commonly used by previous investigators to design divided wall columns, have not been applied. In contrast, a shortcut method based on Underwood's equations has been introduced. Moreover, it is shown that the split of the internal reflux over both sides of the middle wall of the column is bounded and a method for choosing the proper value of the split ratio is suggested. This is a novel approach not attempted before by investigators.
Photodegradation of o‐Cresol with Ag Deposited on TiO2 under Visible and UV Light Irradiation
Authors: Chen H. W. , Ku Y. , Kuo Y. L. 
Published: August 2007

AbstractThis study investigated the effect of dosage of Ag on the characteristics of TiO2, quantum yield, and temporal decomposition behavior of o‐cresol in an annular reactor under ultraviolet (UV) and visible light irradiation. In order to extend light absorption and minimize the rapid recombination during photoreaction, the Ag deposited on TiO2 photocatalysts was prepared by a photodeposition process. The results of diffuse reflectance spectra (DRS) indicated that Ag deposited on TiO2 promoted the optical absorption in the visible region and made it possible for it to be excited by visible light. The degradation rate of o‐cresol with 0.50 wt % Ag/TiO2 under visible light irradiation was 2.0 times that with pure TiO2.
Intramolecular Triarylmethane–Triarylmethylium Complexes with a Naphthalene‐1,8‐diyl Skeleton: Isolation, Structure, and Reactivities of the CH‐Bridged Carbocations
Authors: Takeda Takashi , Kawai Hidetoshi , Fujiwara Kenshu , Suzuki Takanori 
Published: August 2007

AbstractIsolation and low‐temperature X‐ray analyses of intramolecular triarylmethane–triarylmethylium complexes with a naphthalene‐1,8‐diyl‐type skeleton have been achieved. These bridged cations prefer a CH localized structure both in solution and in the solid state. The bridging hydrogen undergoes a facile intramolecular 1,5‐hydride shift from one carbon to another in solution. The CH delocalized geometry is suggested to be the transition‐state structure of the degenerate rearrangement. Charge‐transfer interaction from the triarylmethane to the triarylmethylium units is evident in the electronic spectra. This interaction stabilizes the present cations. Low reactivity toward Brønsted acids indicates that these species are not the reaction intermediates in the acid‐assisted long‐bond cleavage of 1,1,2,2‐tetraarylacenaphthene derivatives.
Molecular mechanics (MM3(π)) conformational analysis of molecules containing conjugated π‐electron fragments: Leucomycin‐V
Authors: Kotev Martin I. , Ivanov Petko M. 
Published: August 2007

AbstractThe conformations of the 16‐membered macrolide antibiotic leucomycin‐V (1) were studied with molecular mechanics. Leucomycin‐V contains a conjugated π‐electron fragment and necessitates special treatment with the MM3(π) modeling protocol. Comparison was made with results from the standard MM3 scheme. The CONFLEX conformational search procedure was used for finding low‐energy conformations. The computed data are indicative for the existence of mainly one conformation of the macro‐ring of 1 and minor participation of several others. Intramolecular hydrogen bonds play important roles for the preferred geometry of the macro‐ring and the conformations of the side chains. The most probable macro‐ring conformation of 1 is very similar to the preferred conformation of another 16‐ring macrolide antibiotic, tylosin. The same order of conformational preference for 1 was estimated with the MM3 and the MM3(π) methods. Surprisingly, when changing the chirality of the C(9) macro‐ring atom of 1, the two methods produced different order of conformational preferences for the 9‐epi form (2), as well as enhanced population of several clusters of conformations. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Prospective investigation of the cigarette smoking–head and neck cancer association by sex
Authors: Freedman Neal D. , Abnet Christian C. , Leitzmann Michael F. , Hollenbeck Albert R. , Schatzkin Arthur 
Published: August 2007

AbstractBACKGROUND.Men are approximately 3 times more likely to develop squamous cancers of the head and neck (oral cavity, pharynx, and larynx) than women. Very few prospective studies have examined the association between cigarette smoking and cancers of the head and neck in women, even though the rates of smoking in women are increasing rapidly worldwide.METHODS.The association between cigarette smoking and head and neck cancer was investigated in 476,211 participants, aged 50–71 years, of the National Institutes of Health/American Association of Retired Persons (NIH‐AARP) diet and health study by using age‐standardized incidence rates and hazard ratios from Cox models adjusted for other risk factors for these cancers.RESULTS.Over the course of follow‐up (1995 through 2000), 584 men and 175 women were diagnosed with head and neck cancer. Nonsmoking (24.4), former smoking (36.9), and current smoking (147.3) men had higher rates of incident head and neck cancer per 100,000 person‐years of follow‐up than women did in each equivalent category of cigarette use (non: 4.8; former: 17.2; current: 75.7). The hazard ratios associated with smoking were significantly larger in women (12.96; 95% confidence interval [CI], 7.81–21.52) than in men (5.45, 95% CI, 4.22–7.05; P for interaction: <.001) for head and neck cancer overall and also for the 3 subsites (oral cavity, oro‐hypopharynx, and larynx) examined in stratified analyses. Ever‐smoking accounted for 45% of head and neck cancers in men and 75% in women, assuming causality.CONCLUSIONS.Cigarette smoking is a strong risk factor for head and neck cancer in both men and women. Incidence rates of head and neck cancer were higher in male smokers than female smokers, but smoking may explain a higher proportion of head and neck cancer in women than in men. Cancer 2007. Published 2007 by the American Cancer Society.
Independent predictors of cancer‐specific survival in transitional cell carcinoma of the upper urinary tract
Authors: Novara Giacomo , De Marco Vincenzo , Gottardo Fedra , Dalpiaz Orietta , Bouygues Vianney , Galfano Antonio , Martignoni Guido , Patard Jean Jacques , Artibani Walter , Ficarra Vincenzo 
Published: August 2007

AbstractBACKGROUND.The objective of the current study was to identify variables that were predictive of cancer‐specific survival in patients with nonmetastatic transitional cell carcinoma of the upper urinary tract (UUT‐TCC).METHODS.Clinical and pathologic data from 269 patients who underwent nephroureterectomy for UUT‐TCC from 1989 to 2005 in 3 urologic European centers were collected retrospectively. Log‐rank tests and Cox proportional‐hazards regression models were used for univariate and multivariate analyses.RESULTS.Two hundred fifty patients underwent nephroureterectomy, and 19 patients underwent concomitant cystectomy for synchronous muscle‐invasive bladder cancer. The median follow‐up of the whole cohort was 34 months, and the median follow‐up of the patients who remained alive and disease‐free was 52 months. At follow‐up, 57 cancer‐related deaths (21.2%) were censored, and 169 patients (62.8%) were alive and disease‐free. On univariate analysis, a history of previous bladder cancer, pathologic stage of the primary tumor and lymph nodes, tumor grade, the presence of lymphovascular invasion, tumor site, synchronous muscle‐invasive bladder TCC, and tumor multifocality were associated with cancer‐specific survival probabilities. On multivariate analysis, pathologic stage of the primary tumor and lymph nodes, tumor multifocality within the UUT, synchronous muscle‐invasive bladder TCC, and a history of bladder TCC before the diagnosis of UUT‐TCC were independent predictors of cancer‐specific survival probabilities.CONCLUSIONS.In a multi‐institutional dataset of patients who had undergone nephroureterectomy for UUT‐TCC, the current results indicated that pathologic stage of the primary tumor and lymph nodes, a history of prior bladder TCC, the presence of synchronous muscle‐invasive bladder cancer, and tumor multifocality within the UUT were independent predictors of cancer‐specific survival probabilities. Cancer 2007. © 2007 American Cancer Society.