bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced corrosion protection coatings prepared from soluble electronically conductive polypyrrole‐clay nanocomposite materials
Authors: Yeh Jui‐Ming , Chin Chih‐Ping , Chang Susan 
Published: April 2003

AbstractA series of electronically conductive nanocomposite materials that consisted of soluble polypyrrole (PPY) and layered montmorillonite (MMT) clay platelets were prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PPY matrix via an in situ oxidative polymerization with dodecylbenzene sulfonic acid (DBSA) as dopant. Organic pyrrole monomers were first intercalated into the interlayer regions of organophilic clay hosts and followed by a one‐step oxidative polymerization. The as‐synthesized electronically conductive polypyrrole–clay nanocomposite (PCN) materials were then characterized by Fourier transformation infrared (FTIR) spectroscopy, wide‐angle powder X‐ray diffraction (XRD), and transmission electron microscopy (TEM). PCNs in the form of coatings with low clay loading (e.g., 1.0 wt %) on cold‐rolled steel (CRS) were found to exhibit much better in corrosion protection over those of pristine PPY based on a series of electrochemical measurements including corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Effects of the material composition on the thermal stability, optical properties, and electrical conductivity of pristine PPY along with PCN materials, in the form of fine powder, powder‐pressed pellet, and solution, were also studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), UV‐visible absorption spectra, and four‐point probe technique, respectively. The viscosity of PPY existed in PCN materials and pristine PPY were determined by viscometric analysis with m‐cresol as solvent. The heterogeneous nucleating effect of MMT clay platelets in PPY matrix was studied by wide‐angle powder XRD. The corresponding morphological images of the nucleating behavior of clay platelets in PPY matrix were investigated by scanning electron microscopy (SEM). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3264–3272, 2003
PET microfiber prepared by carbon dioxide laser heating
Authors: Suzuki Akihiro , Mochizuki Noriaki 
Published: April 2003

AbstractIn preliminary experiments to optimize the condition of a laser heating, zone drawing for poly(ethylene terephthalate) (PET) fiber, a microfiber was prepared by a continuous‐wave carbon dioxide (CW CO2) laser heating. CW CO2 laser heating was carried out at an extremely low applied tension (σa) at a higher laser power density (PD) as compared to the optimum condition for the laser heating, zone drawing of PET fiber reported previously. The microfibers were obtained by CO2 laser heating carried out at a PD of 15.8 W cm−2 and under a σa of 0.66 MPa or lower. The diameter of the fiber decreased with a decreasing σa and increasing PD. The smaller the diameter, the higher was its birefringence. The smallest diameter fiber obtained at σa = 0.17 MPa at PD = 21 W cm−2 had a diameter of 4.5 μm and a birefringence of 0.112, and its draw ratio estimated from the diameter reached 3086 fold. Such a high draw ratio was not previously attained by any drawing method. In a wide‐angle X‐ray diffraction photograph of the smallest diameter fiber, indistinct reflections due to oriented crystallites were observed. An SEM micrograph of the smallest diameter fiber showed a smooth surface without any crack and was uniform in diameter. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3297–3283, 2003
Polyimide bonded magnets: Processing and properties
Authors: Yudin V. E. , Otaigbe J. U. , Bui Tho X. , Svetlichnyi V. M. 
Published: April 2003

AbstractWe report a new method of polyimide synthesis based on the interaction of dianhydrides with acylated diamines for preparing a melt processable mixture of prepolymer and rare earth magnetic alloy particles in the form of 75–100 μm particles. This mixture can be easily converted to useful thermoplastic polyimide bonded magnets by heating at 300°C. It is shown that the prepolymer based on 1,3‐bis(3,4‐dicarboxyphenoxy)benzene dianhydride and the diacetyl derivative of 2,2‐bis(4‐(4‐aminophenoxy)phenyl)sulfone diamine after removing less than 5% by weight of the volatile components can be melted at 220–240°C to give a fluid with a viscosity of 10–20 Pas. This low viscosity of the prepolymer facilitates blending it with magnetic particles at relatively high volume fractions (up to 85 vol %) that are not possible using conventional methods. The resulting polyimide‐bonded magnets exhibit excellent thermal stability and a high storage modulus of 10 GPa at 400°C. Magnetic property measurements showed a ≥10% increase in energy products over that of typical commercial bonded magnet materials such as the ones containing thermoplastic poly(phenylene sulfide) or polyamide matrices. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3151–3158, 2003
Improved Repeated Confidence Bounds in Trials with a Maximal Goal
Authors: Brannath W. , König F. , Bauer P. 
Published: April 2003

AbstractRepeated confidence intervals can be computed at every interim analysis of a flexible group sequential design without the need to stop the trial with a pre‐planned stopping rule. Often, however, there is a maximal goal such that the trial is surely stopped if this goal is reached. This induces a maximal stopping rule, and repeated confidence intervals are strictly conservative, when adhering to it. A modification is proposed which uniformly improves the one sided repeated confidence interval in such a situation. It preserves the monitoring character, and leads to uniformly smaller intervals, when reaching the maximal goal at an interim analysis. The modification is worked out for two stage designs and is indicated for multi‐stage trials. The extent of the improvement is quantified for two simple scenarios.
A comparison of the Dodo, EST, and ATI factors among comorbid stimulant‐dependent, depressed patients
Authors: Beutler Larry E. , Moleiro Carla , Malik Mary , Mark Harwood T. , Romanelli Robert , Gallagher‐Thompson Dolores , Thompson Larry 
Published: April 2003

AbstractDescribes pilot findings from a treatment development study aimed at improving treatment for comorbid depressed and chemically‐dependent patients. A comparison of standard RCT analyses with Hierarchical Multiple Regression (HLM) procedures revealed the latter to be more sensitive to the relative effects of patient, treatment, and patient–treatment matching variables among a small sample of (N = 40) depressed, stimulant‐abusing patients. Participants were randomly assigned to one of three treatments, a standard Cognitive Therapy for Drug Abuse (CT), a contrasting Cognitive‐Narrative Therapy (NT), and a Prescriptive Therapy (PT), the latter of which selectively applied procedures from both of the other two treatments following an Aptitude × Treatment Interaction (ATI) model. The results supported a multiple factor view of psychotherapy effects, including the hypothesis that patient, treatment, relationship, and patient‐therapy matching variables add independent power to the prediction of treatment outcome, especially during follow‐up. ATI effect sizes were stronger than those associated with specific treatments. Copyright © 2003 John Wiley & Sons, Ltd.
Recall of threat and submissiveness in childhood: development of a new scale and its relationship with depression, social comparison and shame
Authors: Gilbert P. , Cheung M. S‐P. , Grandfield T. , Campey F. , Irons C. 
Published: April 2003

AbstractResearch on the link between recall of early parenting and psychopathology has focused on recall of parental behaviours such as neglect, rejection, low warmth and overprotection. This study investigates recall of the personal feelings of perceived threat and subordination in childhood. A short, new self‐report scale was developed, called the Early Life Experiences Scale (ELES) and given to 225 undergraduate students. Analysis revealed three factors: a factor for threat, a factor related to submissiveness and a factor related to feeling (un)valued. All participants completed measures of recall of parental behaviour and depression; 119 also completed a shame scale, and 106 completed a social comparison scale. Both the recall of parental behaviour measure and the ELES correlated significantly with depression, social comparison and shame. However, a standard multiple regression analysis found that only the submissive factor of the ELES predicted depression. Copyright © 2003 John Wiley & Sons, Ltd.
Biopolymer albumin for diagnosis and in drug delivery
Authors: Patil Gayathri V. 
Published: April 2003

AbstractThis article reviews the developmental stages and strategies used to assess the biomedical utility of biopolymer albumin from the 1970s to early 2002. The basic method and mechanism(s) of preparation of albumin microspheres and subsequent modifications made to overcome the drawbacks of earlier approaches and the need for further developments are discussed, as are the processing parameters and the level of various ingredients affecting the physicochemical properties of the albumin microspheres. Different equations proposed by various investigators to modulate in vitro release kinetics are reviewed. The microscopic structural and surface properties, the chemical modification of the biopolymer (e.g., cationization, tagging with amino acids and sugar moieties) for tissue specificity or to influence the release profile and biodegradation are discussed. An array of potential diagnostic applications and the use of albumin microspheres as a drug delivery system are reviewed. Drug Dev. Res. 58:219–247, 2003.© 2003 Wiley‐Liss, Inc.
Simultaneous detection of S‐adenosylmethionine and S‐adenosylhomocysteine in mouse and rat tissues by capillary electrophoresis
Authors: Uthus Eric O. 
Published: April 2003

AbstractA capillary electrophoresis method for the determination of S‐adenosylmethionine (SAM) and S‐adenosylhomocysteine (SAH) in rat liver and kidney and mouse liver is described. The method can also be used to determine SAM in whole blood. The method provides rapid (approximately 16 min sample to sample) resolution of both compounds in perchloric extracts of tissues. Separation was performed by using an uncoated 50 μm ID capillary with 60 cm total length (50 cm to the detector window). Samples were separated at 22.5 kV and the separation running buffer was 200 mM glycine pH 1.8 (with HCl). The method compares favorably to HPLC methods (r 2 = 0.994 for SAM, r 2 = 0.998 for SAH) and has a mass detection limit of about 10 fmol for both SAM and SAH at a signal‐to‐noise ratio of 3. The method is linear over ranges of 1–100 μM SAM and 1–250 μM SAH. This method can be used to determine tissue concentrations of SAM and SAH, two metabolites that can provide insight into many biological processes.
Predicting heats of combustion of polymers using an empirical approach
Authors: Hshieh Fu‐Yu , Hirsch David B. , Beeson Harold D. 
Published: April 2003

AbstractThe heats of combustion of 75 pure organic polymers with various chemical classes were used to develop empirical equations for predicting the gross and net heats of combustion of organic polymers. The equations were developed using atomic contribution and multiple linear regression methods. The gross and net heats of combustion per unit weight can be obtained by dividing the gross and net heats of combustion per mole by the molecular weight of the monomer. The average absolute % error for the predictions is 3.9%. In addition, two previously developed empirical equations, which predict the heats of combustion of organosilicon compounds, were used to predict the heats of combustion of silicone polymers. Copyright © 2003 John Wiley & Sons, Ltd.
Finite volume/mixed finite element analysis of pollutant transport and bioremediation in heterogeneous saturated aquifers
Authors: Gallo Claudio , Manzini Gianmarco 
Published: April 2003

AbstractThe adoption of a suitable pumping–injecting well network and the human enhancement of the activity of soil bacteria, whose metabolism contributes to degrade and transform many pollutants in non‐toxic substances, may be crucial in the process of remediation of contaminated soils. Organic contaminant transport in a subsurface aquifer and its biological degradation kinetics is numerically addressed by using a four contaminant species model. A numerical approach is proposed, that is based on a cell‐centre finite volume method for the system of advection–dispersion equations of contaminants with a mixed‐hybrid finite element method for the solution of a single‐phase Darcy's equation. The effectiveness of the method and its accuracy in retaining the main physical properties of the continuous mathematical model is illustrated by simulating the time evolution of contaminant concentrations in a set of realistic scenarios. Copyright © 2003 John Wiley & Sons, Ltd.
A novel fully‐implicit finite volume method applied to the lid‐driven cavity problem—Part II: Linear stability analysis
Authors: Sahin Mehmet , Owens Robert G. 
Published: April 2003

AbstractA novel finite volume method, described in Part I of this paper (Sahin and Owens, Int. J. Numer. Meth. Fluids 2003; 42:57–77), is applied in the linear stability analysis of a lid‐driven cavity flow in a square enclosure. A combination of Arnoldi's method and extrapolation to zero mesh size allows us to determine the first critical Reynolds number at which Hopf bifurcation takes place. The extreme sensitivity of the predicted critical Reynolds number to the accuracy of the method and to the treatment of the singularity points is noted. Results are compared with those in the literature and are in very good agreement. Copyright © 2003 John Wiley & Sons, Ltd.
Distribution and partition of trace metals in the Amazon basin
Authors: Seyler Patrick T. , Boaventura Geraldo R. 
Published: April 2003

AbstractThe distribution of trace metals (V, Cr, Mn, Co, Cu, Zn, As, Rb, Sr, Mo, Cd, Sb, Cs, Ba, U) was investigated in surface waters and associated particulates in the Amazon mainstream (Solimões and Amazon rivers). Dissolved V, Cu, As, Sr, Ba, U correlate with major ions and appear to be predominantly derived from soluble rocks occurring in the Amazon upper basin. These elements appear conservative in waters and are progressively diluted by less‐concentrated waters coming from the lowland and shield areas. A monthly time series obtained at the Óbidos gauging station shows that temporal variability of trace element concentrations reflects the source, remobilization and/or biological processes occurring in the channel or in the surrounding floodplain lakes. The trace element concentrations in the particulate matter show a clear relationship with the location of the samples. V, Co, Cr, Mn, Sr, Cs and Ba concentrations are higher in the Solimões and the Rio Negro is enriched in Fe, Al and Zn. In the Rio Solimões, V, Cr, Mn, Co, Ni, Zn, Cs and Pb are almost entirely carried by the river particulate matter; Cu, Rb, Sr, Ba and U are transported mainly by the suspended particles, but a dissolved phase contributes to the transport. In the Rio Negro, the proportion of elements transported by the dissolved phase is higher for the whole set of elements. The implications of these results allow us to compute the fluxes from the Amazon River to the Atlantic Ocean. Copyright © 2003 John Wiley & Sons, Ltd.
Rare earth elements in the Amazon basin
Authors: Gerard M. , Seyler P. , Benedetti M. F. , Alves V. P. , Boaventura G. R. , Sondag F. 
Published: April 2003

AbstractThe rare earth element (REE) concentrations of the dissolved and particulate fractions and bed sediment between Manaus and Santarém in the Amazon River, and in some major tributaries, were evaluated. A very important zone in the Amazon basin, the ‘encontro das aguas’ area where the Rio Solimões and the Rio Negro meet, was especially sampled. Different size fractions were isolated by ultrafiltration. Water samples were collected at different stages of the mixing. Three groups of waters are distinguished: group I has a low pH (<5·5) and is represented by the Negro basin rivers; group II has alkalinity less than 0·2 meq l−1 and is represented by the Rios Tapajós and Trombetas; group III has high alkalinity (>0·2 meq l−1) and higher pH (>6·5) and is represented by the Madeira basin rivers, the Solimões and the Amazon. The highest dissolved REE concentration is in the Rio Negro and the lowest in the Rio Tapajós (dissolved REEs vary by more than a factor of ten). The solubility of REEs is pH dependent: in river waters with a pH < 6 the Ce concentration is twice that of La, whereas in rivers with a higher pH the concentrations of Ce and La are similar. Dissolved REE concentrations are positively correlated with the dissolved organic carbon. Correlations between Fe, Al, and La suggest that La is associated with Al (Fe)‐rich organic matter and/or related to dissolved Fe‐rich inorganic material. Dissolved REEs normalized to North American shale composite show an enrichment in intermediate/heavy REEs (from Eu to Er), except for the shields rivers (such as Rio Negro and Rio Trombetas). Both of them are depleted in heavy REEs and show a relative Ce enrichment. In contrast, for the Andeans rivers (such as Rio Solimões), light REEs are slightly depleted and a negative Ce relative anomaly occurs. The pattern of the Amazon River at Óbidos confirms the major influence of the Rios Negro and Solimões with REE fractionation. For the Rio Negro, 60 to 70% of REEs are concentrated in the particulate fraction (>0·2 µm), 20 to 30% are in the colloidal fraction (0·2 µm to 5000 Da) and less than 10% are in solution (<5000 Da). For the Solimões the distribution is different. More than 95% of REEs are in the particulate fraction. In the mixing area, the colloidal fraction is enriched in heavy REEs. Copyright © 2003 John Wiley & Sons, Ltd.
Characteristics of organic matter in the mixing zone of the Rio Negro and Rio Solimões of the Amazon River
Authors: Moreira‐Turcq Patricia F. , Seyler Patrick , Guyot Jean Loup , Etcheber Henri 
Published: April 2003

AbstractThe nature and distribution of organic matter in the mixing zone of black (Rio Negro) and white (Rio Solimões) waters in the Amazon River was studied to understand the processes responsible for its transport and distribution. Water samples from 13 stations, including Rio Negro, Rio Solimões and Rio Madeira and ten stations downstream of the confluence with the Amazon, were collected during a low‐water period. Particulate organic matter (POM; >0·7 µm) and dissolved organic matter (DOM; <0·7 µm) were quantified by analysing elemental carbon and nitrogen and by high‐temperature catalytic oxidation, and characterized by infrared spectrometry and fluorescence microscopy. We also performed adsorption experiments with DOM and alumina particles to determine the adsorption abilities and the nature of the most reactive DOM. Adsorption was estimated by measuring the amount of dissolved organic carbon (DOC) lost during the experiments. We found a significant difference between the measured and theoretical fluxes of the two end members in DOC (−52%), particulate organic carbon (−32%), and particulate organic nitrogen (−59%). This suggests that organic matter is not conservative at the confluence of the two rivers. Among processes affecting POM and DOM during the mixing of the two rivers, adsorption may be one of the principal mechanisms by which the dissolved fraction is removed. Adsorption experiments showed that up to ca 40% of DOC can be removed by adsorption reactions. Furthermore, dissolved organic nitrogen was preferentially adsorbed onto alumina surfaces, which may be important for the fractionation of organic matter in the Amazon river system and seems to be related to the origin and freshness of the DOM. Copyright © 2003 John Wiley & Sons, Ltd.
Transport, distribution and speciation of mercury in the Amazon River at the confluence of black and white waters of the Negro and Solimões Rivers
Authors: Maurice‐Bourgoin Laurence , Quemerais Bernadette , Moreira‐Turcq Patricia , Seyler Patrick 
Published: April 2003

AbstractThis study describes the transport and speciation of mercury (Hg) and the associated role of organic matter in these processes at the confluence of the Negro (‘black waters’) and Solimões (‘white waters’) Rivers, which form the Amazon River. The Negro has the highest total Hg content (11·6 to 18·2 ng l−1) due to the extreme particulate Hg concentrations (2074 ng g−1 at the surface), 10 to 20 times higher than those measured in other Amazon tributaries. The total organic carbon (TOC) consists primarily of dissolved organic carbon, which corresponds to 89% and 66% of the TOC in the Negro and Solimões Rivers respectively, and is mainly composed of humic substances, carriers for most of the metal ions transported in rivers. At the confluence of the Negro and Solimões Rivers, the total Hg concentrations decrease markedly. An isotopic mass balance showed that the complete mixing of the two rivers was achieved 25 km downstream of the confluence. At 60 km downstream of the confluence, the flux of Hg decreases to 73 kg day−1, which represents a net losses of 5 kg day−1 and 15 kg day−1 of dissolved Hg and particulate Hg respectively, assuming that the discharge was constant during the sampling survey and without significant lateral input. Moreover, the Hg losses are correlated with the total suspended matter concentrations, which vary throughout the mixing zone, and also with the particulate and dissolved organic carbon distribution. We suggest that the dissolved loss occurs during the flocculation of organic matter within the zone of rapidly changing physical and chemical conditions downstream of the confluence, and that the particulate loss is by the deposition of particles along the mixing zone favoured by decreasing stream velocities during the sampling survey. Adsorption processes of Hg on dissolved organic matter seem to be responsible for the decrease of dissolved Hg concentrations in the mixing zone. Copyright © 2003 John Wiley & Sons, Ltd.