bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supporting mechanism of non‐toxic chromium (III) acetate on silica for preparation of Phillips ethylene polymerization catalysts
Authors: Qiu Pengyuan , Li Xiaofang , Zhang Shiliang , Cheng Ruihua , Dong Qi , Liu Boping , Li Liuzhong , Yu Yongling , Tang Yan , Xie JianLing , Wang Wenqing 
Published: July 2009

AbstractPhillips catalyst is an important kind of industrial polyethylene catalyst. As early as in the late 1970s, CrO3 was substituted by chromium (III) acetate for the preparation of Phillips catalyst on the industrial scale owing to health and environmental considerations. There is still considerable research focusing on the relations between the preparation process and catalyst properties in academics. In this work, the supporting mechanism of chromium (III) acetate on silica has been studied by Thermogravimetry–Differential Thermal Analysis (TG‐DTA), and Electron Spin Resonance (ESR), in comparison with that of supporting CrO3 on SiO2. The basic chromium (III) acetate supported on high surface area silica gel decomposed differently from that for bulk basic chromium acetate when decomposition temperature was decreased by 15 °C. The decomposition temperature was 299 °C for Cr3(OH)2(Ac)7/SiO2 catalyst precursor, which would be firstly transferred into CrO3 followed by supporting on silica surface as chromate species. The further weight loss came from thermal inductive reduction of chromate species into Cr2O3, which was also supported by the results of colors of catalysts. Moreover, with the increase of chromium loading of Cr3(OH)2(Ac)7/SiO2, such thermal inductive reduction became more severe. ESR spectra of Cr3(OH)2(Ac)7/SiO2 and CrO3/SiO2 catalyst precursors showed that a small amount of supported Cr5+ can exist stably on silica gel surface at temperatures higher than 200 °C. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Numerical simulation of flow and heat transfer in connection of gasifier to the radiant syngas cooler
Authors: Ni Jianjun , Liang Qinfeng , Yan Zhuoyong , Yu Zunhong , Yu Guangsuo 
Published: July 2009

AbstractThe connection of gasifier to the radiant syngas cooler has been regarded as a key technology for heat recovery system. Multiphase flow and heat transfer processes presented in this work considers particle deposition and radiation model to mixture of non‐gray gas with particles. An axisymmetric simulation of the multiphase flow in an industrial scale connection is performed. The standard k‐ε model, Renormalization group (RNG) k‐ε model and Realizable k‐ε model turbulence model are proposed. The particle motion is modeled by discrete random walk model. The discrete ordinates model (DOM), P‐1 and discrete transfer model (DTRM) are used to model the radiative heat transfer. The effect of particles on the radiative heat transfer was taken into account when the DOM and P‐1 model were used. The absorption coefficient of the gas mixture is calculated by means of a weighted‐sum‐of‐gray‐gas (WSGG) model. The results with the DOM and P‐1 model are very similar and close to practical condition. A large number of particles are deposited on the cone of gasifier which is the top of connection. Maximum temperature difference is approximate 7 K when the cooling tube heights change from 0.5 m to 1.5 m. The temperature inside has a linear relationship with operating temperature. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Investigation of mineral composition of oil shale
Authors: Wang Dong‐Mei , Xu Ying‐Mei , He De‐Min , Guan Jun , Zhang Oiu‐Min 
Published: July 2009

AbstractThe aim of this paper is to identify the mineral composition of oil shale from different locations and relate it to their interval of occurrence. Thermogravimetric analysis (TGA), diffuse reflectance infrared Fourier transforms spectroscopy (DRIFTS) and X‐ray diffraction (XRD) methods were used for this invetigation. Hydrogen peroxide was used as the oxidant to eliminate the influence of organic matter in TGA. DRIFTS results indicated that most of the kerogen is in aliphatic hydrocarbon form and the peak of hydrocarbon nearly disappeared after oxidation. XRD results indicated that quartz, muscovite, kaolinite and calcite are the dominant minerals. Longkou and Changchun oil shale samples contain high percentage of calcite (12.9 and 11.7% CO2 respectively) while Fushun and Huadian oil shale samples contain less than 6% CO2. Especially, in Fushun oil shale sample, the content is below 3%. Kaolinite is found in Fushun oil shale sample, while muscovite is only found in Huadian oil shale sample. Integration of the XRD, DRIFTS and TGA results of the oil shale samples from different locations has provided a better way of mineral composition identification. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Synthesis of a photo‐patternable cross‐linked epoxy system containing photodegradable carbonate units for deep UV lithography
Authors: Huh Geun , Kwon Ki‐Ok , Cha Sang‐Ho , Yoon Sang‐Woong , Lee Moo Young , Lee Jong‐Chan 
Published: July 2009

AbstractBis(2‐(oxiran‐2‐ylmethyl)‐1,3‐dioxoisoindolin‐5‐yl) carbonate and polymers containing 9‐anthracenylmethylmethacrylate (AMMA), p‐tert‐butoxy styrene (PTBS), and methacrylic acid (MAA) monomeric units were synthesized with the aim of developing a novel photo‐patternable cross‐linked epoxy system. The oxirane groups in bis(2‐(oxiran‐2‐ylmethyl)‐1,3‐dioxoisoindolin‐5‐yl) carbonate were reacted with the carboxylic acid in the polymer to generate a cross‐linked epoxy film, and the photo degradation of the cross‐linked film was achieved through decomposition of the carbonate groups in the cross‐linked film by deep UV irradiation. Because the copolymer containing anthracene groups has relatively high reflective index and absorption at 248 nm, this cross‐linked system can be applied to patternable bottom antireflective coating materials for deep UV lithography applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A survey of student perceptions of team‐based learning in anatomy curriculum: Favorable views unrelated to grades
Authors: Vasan Nagaswami S. , DeFouw David O. , Compton Scott 
Published: July 2009

AbstractTeam‐based learning (TBL) combines independent out of class preparation with in class small group discussion. We adopted TBL in teaching first year medical gross anatomy. In this study, we evaluated student perceptions of TBL by using a survey that elicited perceptions of both pedagogy and mode of learning. Anatomy lectures were replaced with required preclass readings, self‐assessment quizzes, small group discussions of assignments, and groups retaking the same quizzes for deeper learning. At the course conclusion, students were surveyed to assess their preference for TBL, their perceptions of TBL effectiveness, and their perceptions of successful interpersonal relationships within groups. Respondents (n = 317; 89% response) were asked to rate the extent that they agreed (−2 = strongly disagree; −1 = disagree; 0 = neutral; 1 = agree; and 2 = strongly agree). A principal components factor analysis with varimax rotation identified two 8‐item factors: “perceptions of TBL” and “perceptions of teamwork.” Internal consistency for each was high [Cronbach's alpha = 0.908 (preference for TBL); 0.884 (preference of teamwork)]. Results of one‐way analysis of variance between Honors/High Pass/Pass/Fail students indicated that Honors (n = 73) tended to rate perceptions of TBL higher than Pass (n = 54) [mean difference = 2.92; 95% CI (0.05, 5.79)], and also higher than Fail (n = 11) [mean difference = 6.30; 95% CI (1.13, 11.47)]. However, each had overallpositive ratings. No difference was noted between mean ratings of teamwork, which were also, overall, positive. We conclude that medical students view TBL favorably irrespective of their grades. Anat Sci Educ 2:150–155, 2009. © 2009 American Association of Anatomists.
Risky choice framing: Task versions and a comparison of prospect theory and fuzzy‐trace theory
Authors: Kühberger Anton , Tanner Carmen 
Published: July 2009

AbstractFraming effects are said to indicate irrationality in decision making because they illustrate that linguistically different descriptions of equivalent options lead to inconsistent choices. A review of the literature on the effects of adding, or subtracting, implicated complements of the sure option shows that this leads to a classic framing effect, a reversal of the classic effect, or no framing effect. Thus, the assumption of equivalence of formulations is not justified. In addition we provide a test of two major, but opposing theories on framing, prospect theory and fuzzy‐trace theory. Based on an online study we investigated the effects of subtracting complements of the risky option. The results are more consistent with fuzzy‐trace theory than with prospect theory. The consequences of these findings for the application of formal models like prospect theory, and for rationality, are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Developmental exposure to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin alters postnatal T cell phenotypes and T cell function and exacerbates autoimmune lupus in 24‐week‐old SNF1mice
Authors: Mustafa Amjad , Holladay Steven D. , Goff Matthew , Witonsky Sharon , Kerr Richard , Weinstein Danielle A. , Karpuzoglu‐Belgin Ebru , Gogal Robert M. 
Published: July 2009

AbstractBACKGROUND:Untreated, more than 95% of female SWR x NZB: F1(SNF1) mice spontaneously develop a fatal lupus‐like glomerulonephritis by 8 months‐of‐age, while disease onset in males is much slower.METHODS:Timed‐pregnant SNF1mice (10 per treatment) were exposed to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) on gestational day (GD) 12 by oral maternal gavage with 0, 40, or 80 μg/kg TCDD.RESULTS:Offspring of the TCDD‐exposed dams showed numerous alterations in T lineage cells at 24 weeks‐of‐age. Females but not males showed decreased CD4+8+and increased CD4−8−thymocytes. Females also showed increased autoreactive CD4+Vβ17a+axillary and inguinal lymph node T cells. Concanavalin A–stimulated splenocytes from prenatal TCDD‐treated mice produced decreased interleukin 17 (IL‐17) in the females while males showed increased IL‐2 and IFN‐γ, and diminished IL‐4. Mitogen‐stimulated pan‐lymphoproliferative responses were significantly increased across sex by TCDD. Anti‐IgG and anti‐C3 immune complex deposition in kidneys was present in the males after TCDD, and visibly worsened in females.CONCLUSIONS:Developmental TCDD exposure can permanently alter T lymphopoiesis in autoimmune‐prone SNF1 mice. The alteration profile is beyond the classic immune suppression response, to also include exacerbation and induction of a lupuslike autoimmune disease. Birth Defects Research (Part A) 2009. © 2009 Wiley‐Liss, Inc.
Behavioral change related to Wenchuan devastating earthquake in mice
Authors: Li Yonghong , Liu Yanyou , Jiang Zhou , Guan Junwen , Yi Guixi , Cheng Shuting , Yang Bo , Fu Tianming , Wang Zhengrong 
Published: July 2009

AbstractIt has been suggested that some animals are much more capable of perceiving certain kinds of geophysical stimuli which may precede earthquakes than humans, but the anecdotal phenomena or stories about unusual animal behaviors prior to an earthquake should be interpreted with objective data. During the Wenchuan magnitude 8.0 earthquake that happened in Wenchuan county (31.0° north latitude, 103.4° east longitude) of Sichuan province, China, on May 12, 2008, eight mice were monitored for locomotor activity and circadian rhythm in constant darkness with temperature 22–24 °C and humidity 55–65% for 38 days. The ongoing monitoring of locomotor activity of mice in our laboratory made it possible to design a posteriori study investigating whether the earthquake was associated with any change in animal behavior. Based on analyzing the recorded data with single cosinor, we found that the locomotor activity dramatically decreased in six of these eight mice on day 3 before the earthquake, and the circadian rhythm of their locomotor activity was no longer detected. The behavioral change lasted for 6 days before the locomotor activity returned to its original state. Analyses of concurrent geomagnetic data showed a higher total intensity during the span when the circadian rhythm in locomotor activity weakened. These results indicated that the behaviors, including circadian rhythm and activity, in these mice indeed changed prior to the earthquake, and the behavioral change might be associated with a change of geomagnetic intensity. Bioelectromagnetics 30:613–620, 2009. © 2009 Wiley‐Liss, Inc.
A Bayesian Long‐term Survival Model Parametrized in the Cured Fraction
Authors: Castro Mário de , Cancho Vicente G. , Rodrigues Josemar 
Published: July 2009

AbstractThe main goal of this paper is to investigate a cure rate model that comprehends some well‐known proposals found in the literature. In our work the number of competing causes of the event of interest follows the negative binomial distribution. The model is conveniently reparametrized through the cured fraction, which is then linked to covariates by means of the logistic link. We explore the use of Markov chain Monte Carlo methods to develop a Bayesian analysis in the proposed model. The procedure is illustrated with a numerical example.
Highly selective determination of phenolphthalein by flow injection chemiluminescence method based on a molecular imprinting polymer
Authors: Yu Jinghua , Ge Lei , Dai Ping , Zhang Congcong , Ge Shenguang , Huang Jiadong 
Published: July 2009

AbstractThe phenolphthalein‐imprinted polymer was prepared with methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross‐linker. Taking advantage of the quenching effect of phenolphthalein on the potassium permanganate–HCl–anhydrous alcohol chemiluminescence system, a new model was established to determine phenolphthalein by a highly selective flow injection chemiluminescence method. The traditional flow‐though cell was replaced with a novel flow path using a Y‐shaped polymethyl methacrylate column, through which the three reactants were injected simultaneously. The linear range of this assay was from 1.0 × 10−8 to 1.0 × 10−6 g/mL (r = 0.9978). The limit of detection was 8.9 × 10−9 g/mL. The relative standard deviation for the determination of 1.0 × 10−8 g/mL phenolphthalein solution was below 2.9% (n = 11). The proposed method was applied to the determination of phenolphthalein in real samples with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Terminalia chebula aqueous extract on oxidative stress and antioxidant status in the liver and kidney of young and aged rats
Authors: Mahesh Ramalingam , Bhuvana Shanmugham , Hazeena Begum Vava Mohaideen 
Published: July 2009

AbstractWe evaluated the preventive effects of Terminalia chebula (T. chebula) aqueous extract on oxidative and antioxidative status in liver and kidney of aged rats compared to young albino rats. The concentrations of malondialdehyde (MDA), lipofuscin (LF), protein carbonyls (PCO), activities of xantione oxidase (XO), manganese‐superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione‐S‐transferase (GST), and glucose‐6‐phosphate dehydrogenase (G6PDH), levels of glutathione (GSH), vitamin C and vitamin E were used as biomarkers. In the liver and kidney of aged animals, enhanced oxidative stress was accompanied by compromised antioxidant defences. Administration of aqueous extract of T. cheubla effectively modulated oxidative stress and enhanced antioxidant status in the liver and kidney of aged rats. The results of the present study demonstrate that aqueous extract of T. cheubla inhibits the development of age‐induced damages by protecting against oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.
Carbonated Water Purification of Carbon Nanotubes Synthesized on Fe‐CaCO3 Catalysts
Authors: See C. H. , Husin A. , Harris A. T. 
Published: July 2009

AbstractCarbon nanotubes (CNTs) grown on CaCO3 substrate can be easily purified using dilute mineral acids. Here it is shown, for the first time, that as‐synthesized CNTs can be purified to a large extent with carbonated water. The amount of CaCO3 that can be dissolved is dependent on the solution volume and the quantity of dissolved CO2. Between 38 and 57 wt % of CaCO3 was removed under atmospheric pressure, and increased to 80 wt % using water pretreated to 3 bar CO2 pressure. CO2 partial pressure was found to have the most significant impact by facilitating the formation of Ca(HCO3)2. No detrimental effects on CNT quality was determined by Raman spectroscopy and thermogravimetric analysis.
Stabilization of Metal Nanoparticles – A Chemical Approach
Authors: Gromov A. A. , Strokova Y. I. , Teipel U. 
Published: July 2009

AbstractThe chemical and physical mechanisms for the formation of passivation coatings on active metal nanoparticles were studied in this work. The passivation processes involved in the formation of coatings on nanoparticles were analyzed by SEM, TEM, XRD, EDS, DTA‐TG and chemical analysis. Inorganic passivation coatings for aluminum nanopowders were more effective in terms of thermal stability than organic ones. The stability of organic passivation coatings to further oxidation did not depend on the type of coating, but instead depended on the particle size of the passivated powders. A new advanced approach involving a metal nanopowder passivation technique has been applied.
Design of a Micro‐Structured System for the Homogenization of Dairy Products at High Fat Content – Part III: Influence of Geometric Parameters
Authors: Köhler K. , Aguilar F. A. , Hensel A. , Schubert K. , Schubert H. , Schuchmann H. P. 
Published: July 2009

AbstractPartial homogenization using a microstructured SHM (Simultaneous Homogenizing and Mixing) valve (as presented in part I) significantly reduces aggregation of fat globules during their homogenization by feeding the continuous phase directly into the droplet disruption zone. It allows homogenizing cream up to at least 42 vol.‐% of fat, thus reducing processing costs significantly without loss in product quality (process intensification). In contrary to conventional milk technology, droplet sizes can be reduced at high fat contents with increasing pressure or increasing temperature of the homogenized stream (as presented in part II). This breaks new ground in dairy product design. In part III our focus is set on the influence of the SHM valve geometry on the homogenization results. No significant influence was found for the shape of the flow channels. In contrast, the distance at which the mixing streams enter has a significant impact on the homogenization results. For standard SHM valves with a T‐shaped mixing unit we found an optimal distance at around 5 mm behind the valve outlet. In order to separate the tasks of implying a counter‐pressure and instant diluting, an SHM2 double‐valve configuration is suggested combining a double homogenization valve with a mixing unit. This offers the possibility to profit from counter‐pressure just as well as in full‐stream homogenization and gives more freedom in the mixing inlet design. Optimal distances for the mixing stream inlet are between 0 and 5 mm.
Applying the Taguchi Method to Develop an Optimized Synthesis Procedure for Nanocrystals of T‐Type Zeolite
Authors: Tehrani Matin K. , Bastani D. , Kazemian H. 
Published: July 2009

AbstractThe effects of H2O/SiO2, TMAOH/SiO2, Na/(Na+K), and SiO2/Al2O3 ratios in the parent gels on the crystallization of nanoparticles of T‐type zeolites were studied. A Taguchi orthogonal experimental design with the above‐mentioned parameters (each at three levels) was used to optimize the experiment parameters by the analysis of variances (ANOVA). Applying the Taguchi method significantly reduced the time and cost required for optimization. The synthesized products were characterized by X‐ray diffraction and scanning electron microscopy. As a result of the Taguchi analysis, H2O/SiO2 and TMAOH/SiO2 were the most influencing parameters for the synthesis of zeolite T.
Preparation and Flow Behaviour of Oil‐In‐Water Emulsions Stabilised by Hydrophilic Silica Particles
Authors: Braisch B. , Köhler K. , Schuchmann H. P. , Wolf B. 
Published: July 2009

AbstractEmulsions are a common form of material and are encountered in products including foods, cosmetics, and pharmaceuticals. Appropriate formulation and processing ensures stability and quality. The research reported is concerned with the use of nano‐particles for interfacial stabilisation of oil‐in‐water (o/w) emulsions. This is a route far less often chosen by formulation engineers than interfacial stabilisation based on small molecular surfactants. Known concepts of stabilising simple o/w emulsions with hydrophilic silica particles were applied. The emulsion components were carefully selected in view of their application relevance in consumer goods such as foods and creams. Emulsions stable against coalescence were formulated based on discrete 230 nm silica particles and corn oil. The viscosity behaviour of the emulsions was characterised after suppressing creaming through dissolution of a thickening agent in the continuous emulsion phase. The emulsions were shear‐thinning and viscosity levels were reduced after removal of free particles. Particle stabilisation of o/w interfaces alters the product characteristics of emulsion‐based products, giving formulation engineers novel ways to adjust product rheologies.
Epoxidation of a Series of C2–C6 Olefins in the Gas Phase
Authors: Berndt T. , Bräsel S. 
Published: July 2009

AbstractEpoxidation of ethylene, propylene, 2‐methylpropene, trans‐2‐butene, 2‐methyl‐2‐butene, and 2,3‐dimethyl‐2‐butene were carried out in a flow‐through reactor in the homogeneous gas phase at pressures of 0.25–1.0 bar in the temperature range of 250–375 °C. Residence times in the reactor varied from 8.3 to 38 ms. The oxidizing agent needed in the feed gas is ozone. The O3 efficiency (reacted olefin/initial O3) was found to be strongly dependent on the reactivity of the olefin used. For C4–C6 olefins, the O3 efficiency was better than 75 % in each case. For 2‐methyl‐2‐butene and 2,3‐dimethyl‐2‐butene, the O3 efficiency exceeded the theoretical value of 100 % considerably. The selectivity to epoxide was about 90 % independent of the olefin used. Under conditions of nearly total olefin conversion, the high selectivity to the epoxide has been retained as unchanged. There were no indications for consecutive reactions of the epoxides.