bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear low density polyethylenes and their blends: Part 1. Molecular characterization
Authors: Schlund B. , Utracki L. A. 
Published: December 2004

AbstractTen commercial linear low‐density polyethylenes (LLDPE) were characterized by solution viscosity, size exclusion chromatography, SEC, and 13C nuclear magnetic resonance. The resins were copolymers of ethylene with butene, hexene, or octene. They were prepared in gas phase (with narrow or very broad molecular weight distribution), or in solution. The macromolecules were found to be linear. For all but the very broad molecular weight distribution resins the average comonomer sequence length was found to be 1; in the other case diad formation was observed. The weight average molecular weights calculated from SEC, and intrinsic viscosities agreed quite well. Mechanical degradation of LLDPE was observed during the solution viscosity measurements.
Correlations of elastic modulus, cohesive energy density and heat capacity jump of glassy polymers
Authors: Lee Chung J. 
Published: December 2004

AbstractThe elastic modulus of glassy polymers can be calculated from a measurable thermal property of polymers. The correlation of heat capacity jump data with molar modulus of 13 polymers indicated that the calculation of molar modulus from heat capacity jump energy for other glassy polymers is possible.
A boundary element simulation of compression mold filling
Authors: Osswald Tim A. , Tucker Charles L. 
Published: December 2004

AbstractThis paper presents the development of the boundary element equations for the compression molding process of isothermal Newtonian fluids. It shows the numerical implementation of the boundary element equations and presents a simple method of carrying out the domain integral present in the governing equations. The results and accuracy of a boundary element simulation are discussed, and the numerical results compared to experimental values.
A model process for the solvent recycling of polystyrene
Authors: Kampouris E. M. , Papaspyrides C. D. , Lekakou C. N. 
Published: December 2004

AbstractA model solvent technique is presented according to which polystyrene (PS) foam scrap is recovered in the form of small grains. The process mainly comprises dissolution of the waste into benzene or toluene, filtering, dispersion of the solution into water, and subsequent distillation. The alternative solvent/non‐solvent systems have been studied on the basis of solution rheology, operating conditions during the recycling procedure, and extents of recovery of PS and solvent. Eventually, the toluene/water system has been chosen for a larger scale experiment (LSE), the product of which was used for characterization work. No influence on critical properties was detected due to the solvent technique followed.
Torsion Impregnated Cloth Analysis for resin rheological studies
Authors: Lee Charles Y‐C 
Published: December 2004

AbstractThis paper describes the utility of Torsion Impregnated Cloth Analysis, a very versatile technique to characterize resin behavior during cure or after repeated thermal and environmental treatment. Multi‐frequency scan data have been shown to help tremendously in interpreting the behavior during experimentation. The technique is also very useful in defining the cure conditions for new resin chemistry/systems.
Chemical structures and properties of low thermal expansion coefficient polyimides
Authors: Numata Shunichi , Kinjo Noriyuki , Makino Daisuke 
Published: December 2004

AbstractThe relationships, between chemical structures of various aromatic polyimides and their thermal expansion coefficients, were investigated and the properties of low thermal expansion polyimides were elucidated. Such low values were observed for polyimides obtained from pyromellitic dianhydride or 3,3′,4,4′‐biphenyltetracarboxyIic dianhydride and aromatic diamines, which included only benzene or pyridine rings fused at para‐positions without a flexible linkage. It was proposed that these low thermal expansion coefficients were related to the linearity of their polymer molecular skeletons. In particular, PIQ‐L100 (Hitachi Chemical Co. Ltd) is one such low thermal expansion polyimide and, it has excellent mechanical properties, thermal stability, and low absorbed moisture content.
Kinetic studies of the polymerization of nylon‐6 block copolymers
Authors: Limtasiri T. , Grossman S. J. , Huang J. C. 
Published: December 2004

AbstractThe kinetics of the activated anionic polymerization of caprolactam to nylon‐6 and its copolymers has been studied. Nylon‐6 block copolymer and nylon‐6 were prepared at various initial reaction temperatures (140°C to 165°C) by anionic polymerization in an adiabatic dewar flask. Different concentrations of poly(ethylene oxide) (PEO) in 4,4′‐diphenyl methane diisocyanate (MDI)‐capped PEO and 1 mole percent MDI, in a caprolactam solution, were used as the activators with the catalyst, the sodium salt of caprolactam. The kinetics of the reaction were analyzed from an adiabatic temperature rise. A new method was applied to determine the rate parameters. The activation energy, Ea, of nylon‐6 and nylon‐6 block copolymers were found to be 22 kcal/mole. The collision frequency factor, Ao, steadily decreased and the autocatalytic constant, Bo, decreased to a constant value of 16 with the introduction of PEO. However, it was found that the order of reaction, n, was almost a constant value at the second order for all experiments.
Polyolefin properties for rigid food packaging
Authors: Jabarin S. A. , Kollen W. J. 
Published: December 2004

AbstractPolyolefins are used in many rigid plastic packages that are developed for food applications. Generally, the polyolefins used are selected for a balance of cost, ease of molding, and performance properties in a finished package. In this paper some of the physical and sorption properties of polyolefins that are critical to rigid plastic packages are discussed. Initially, a brief review of the performance requirements of plastic food packages will be presented. This is followed by discussions of specific properties of polyolefins such as impact resistance, adhesion and thermal resistance, and how they may be enhanced by coextrusion. Additionally, the sorption of food components such as flavors into polyolefin walls of packages is discussed. Here, the applicable theoretical considerations for sorption and their value for analyzing experimental data are presented. Finally, specific sorption properties of d‐limonene in ethylene‐propylene copolymers and their effects on package performance and design are reported and discussed.
Rheological properties of the liquid crystalline poly(γ‐benzyl α, L‐glutamate) gels in benzyl alcohol
Authors: Shukla Premal , Muthukumar M. 
Published: December 2004

AbstractWe have determined the degree of stiffness of a poly(γ‐benzyl α, L‐glutamate) (PBLG) chain in benzyl alcohol by measuring the intrinsic viscosities of dilute Solutions with differing molecular weights. Viscoelastic properties in oscillatory shear flow have been studied and the dependence of the loss and storage moduli on temperature, composition, and frequency are reported. We have also studied the transient shear stress relaxation behavior of the PBLG gel at different temperatures and concentrations. A comparison has been made between these gels and a classical poly(dimethyl siloxane) (PDMS) network, as well as, typical glassy polymers. Shear creep and recovery measurements have been made for this system. Some extensional step strain experiments using lubricated squeezing have been investigated. Tensile experiments have been made to determine stress‐strain relationship during elongation. Preliminary experiments using the impulse approach to viscoelasticity further indicate the high elastic contribution in the gel.
Interpretation of dynamic mechanical measurements on butyl‐acrylate vinyl‐acetate based systems
Authors: Jourdan C. , Cavaille J. Y. , Perez J. 
Published: December 2004

AbstractDynamic mechanical measurements have been performed in order to get information on the morphology of butyl‐acrylate (BuA)‐vinyl‐acetate (V Ac) based systems. The samples were obtained after emulsion polymerization by three different pathways: (a) Physical blending from homopolymer latexes (b) a conventional batch process leading to a BuA rich core‐V Ac rich shell latex particle (c) a two‐step polymerization leading to an abrupt concentration gradient Inside the particle. Films were obtained by evaporation of water at room temperature. The spectra of the films were interpreted with the help of Kerner's model, and new information has been obtained on the morphology: (i) in the simple blend (case a), the p(V Ac) latexes tend to coalesce to form the matrix; and (ii) it is possible to determine whether random copolymer formed during a polymerization process is located at the interface of p(BuA) and P(V Ac) (case b) or inside the p(BuA) inclusion (case c).
The pressure drop/flow rate equation for non‐Newtonian flow in channels of irregular cross‐section
Authors: Liu Ta‐Jo , Hong Chin‐Nan 
Published: December 2004

AbstractThe pressure drop/flow rate equation for non‐Newtonian fluid flow in channels of irregular cross‐section is determined theoretically by two numerical methods. Two representative non‐Newtonian fluid models, the Ellis and the Herschel‐Bulkley models, have been studied for several commonly encountered non‐circular channels. The empirical methods proposed by Kozicki, et al, and Miller have been analyzed. The validity of their methods is discussed.
Mechanical properties of miscible phenolphthalein poly(ether ether ketone)/polysulfone blends
Authors: Qipeng Guo , Jinyu Huang , Tianlu Chen , Hongfang Zhang , Yuhua Yang , Chunrong Hou , Zhiliu Feng 
Published: December 2004

AbstractThe properties of miscible phenolphthalein poly(ether ether ketone) (PEK‐C)/polysulfone blends have been measured by dynamic mechanical analysis and tensile testing. The blends are found to have single glass transitions that vary continuously with the composition. The tensile moduli exhibit positive deviations from simple additivity as expected for miscible blends. Remarkably, positive deviations were also observed for tensile strength. Embrittlement, or transition from the brittle to ductile mode of failure, occurs at 50‐30 wt % PEK‐C. These observations suggest that mixing on the segmental level has occurred and that there is enough interaction between the components to retard internal mobility significantly.
Isothermal crystallization of isotactic polypropylene in dotriacontane. II: Effect of nucleating agent addition on growth rate
Authors: Lim Gordon B. A. , Lloyd Douglas R. 
Published: December 2004

AbstractIsothermal crystallization growth rates of nucleated and non‐nucleated isotactic polypropylene (iPP) in dotriacontane were determined experimentally by thermal optical microscopy. Adipic acid was used as the nucleating agent. The Lauritzen and Hoffman analysis was used to determine the fold surface energy of the nucleated and non‐nucleated mixtures.
Synthesis and characterization of aromatic polyamides containing an s‐triazine ring with thiophenoxy linkages
Authors: Pal Ravindra R , Patil Prashant S , Salunkhe Manikrao M , Maldar Noormahamad N , Wadgaonkar Prakash P 
Published: January 2005

AbstractA series of aromatic polyamides containing an s‐triazine ring with thiophenoxy linkages was synthesized from two new diacids, namely 2,4‐bis‐(4‐carboxyphenoxy)‐6‐thiophenoxy‐s‐triazine and 2,4‐bis‐(3‐carboxyphenoxy)‐6‐thiophenoxy‐s‐triazine, and commercially available aromatic diamines by using Yamazaki's phosphorylation reaction. The polyamides were obtained in good yields and were characterized by solubility tests, viscosity measurements, FTIR, 1H and 13C NMR spectroscopy, X‐ray diffraction studies and thermogravimetric analysis. The polyamides were found to have inherent viscosities in the range of 0.35 to 0.56 dl g−1 in N,N‐dimethylacetamide (DMAc) at 30 ± 0.1 °C. All the polyamides were readily soluble in solvents such as DMAc, N‐methyl‐2‐pyrrolidone (NMP), N,N‐dimethylformamide (DMF) and m‐cresol. Thermogravimetric analysis of the polyamides indicated no weight loss below 345 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry
The Problems of Quantifying Mineral Liberation: A review
Authors: Austin Leonard G. , Luckie Peter T. 
Published: December 2004

AbstractA review is given of recent publications concerning the theory of liberation of component B from AB material as particle size is reduced, with a view to combining models of liberation with models of size reduction. Although a number of approaches are promising, it is concluded that there is no adequate model of liberation of binary systems suitable for incorporation into a mill model.
Properties of Sprays
Authors: Lefebvre Arthur H. 
Published: December 2004

AbstractThe spray properties of most practical importance, namely mean drop size, drop size distribution, radial and circumferential liquid distribution, cone angle and penetration, are discussed in the context of plain orifice, pressure‐swirl, plain‐jet airblast and prefilming airblast atomization. Equations are presented for estimating mean drop size and spray cone angle in terms of the relevant liquid properties, gas properties, atomizer dimensions, and atomizer operating conditions. The relative merits of these equations are discussed and compared. Some aspects of atomization in need of further research are indicated.
Applied Fractal Geometry and the Fineparticle Specialist. Part I: Rugged boundaries and rough surfaces
Authors: Kaye Brian H. 
Published: December 2004

AbstractFractal Geometry developed in 1977 by B. Mandelbrot describes the structure of rugged systems by extending the concepts of classical dimensional analysis to include a fractional addendum to the topological dimension of a system in order to describe the space filling properties of the rugged system. In the 15 years since the publication of Mandelbrot's book describing his seminal ideas fractal geometry has found many applications in fineparticle science and technology. This body of applied knowledge is now known as Applied Fractal Geometry. The purpose of this review is to focus on the various branches of applied fractal geometry of interest to the fineparticle specialist in a systematic manner. The first part is concerned with ruggedness of fineparticle boundaries, the structure of simple porous bodies, fragmentation and powder production, the assessment of the properties of such materials as paper, and the characterization of rough surfaces. The second part will explore the use of fractal dimensions to describe mixing operations, composite bodies, such as synthetic bones, and paint films.
Johnson's SB Distribution Function as Applied in the Mathematical Representation of Particle Size Distributions. Part 2: Application of numerical results
Authors: Yu Ai‐Bing 
Published: December 2004

AbstractThe validity of the numerical results obtained in Part 1 is examined via some typical examples. The results indicate that the numerical results can be applied to the particle size distribution transformation within the practically tolerated error. On this basis an equation was derived to calculate analytically the mean diameters of a powder. The verification and application of this equation are demonstrated by a typical example. It is shown that the Hatch‐Choate relationship used in the transformation of particle size distributions expressed by the log‐normal distribution is only a special (extreme) case of the present numerical results. Although the numerical simulation cannot always provide a consistent transformation, this approach can greatly facilitate the application of the SB distribution function in powder technology by simplifying the transformation between particle size distributions and the calculation of mean diameters.
The identification of choline and its esters by secondary ion mass spectrometry
Authors: Unger S. E. , Ryan T. M. , Cooks R. G. 
Published: December 2004

AbstractSecondary ion mass spectrometry is shown to provide mass spectra of choline and its esters from which molecular weights and structures are evident. Structure‐spectral correlations are developed using analogies from other forms of mass spectrometry. Spectra can be recorded on metal or paper substrates and individual components can be identified even in complex samples.
Factor analysis and superposition of Auger electron spectra applied to room temperature oxidation of Ni and NiCr21Fe12
Authors: Hofmann S. , Steffen J. 
Published: December 2004

AbstractLow energy valence band Auger transitions are advantageous for the study of the initial stages of metal and alloy oxidation owing to their high surface sensitivity and to their chemical bonding features. However, the latter property leads to difficulties in quantification of the spectra, particularly by using peak‐to‐peak heights in the derivative mode. Therefore, two other methods are applied for a quantitative evaluation of the different elemental bonding states: (a) superposition of standard spectra according to the least mean squares fitting method and (b) factor analysis. The reliability of both methods is compared for the quantitative determination of the kinetics of oxygen reaction with pure Ni and with a NiCr21Fe12 alloy at oxygen pressures between 10−6 Pa and 10−4 Pa. Although both methods give comparable results, only method (b) allows the determination of the chemisorbed oxygen bonding state on Ni using the low energy Ni M23 VV transition. For the NiCrFe alloy, only method (a) gives a clear distinction between nickel and iron oxides.
XPS analysis of ion‐beam‐induced oxidation of silicon substrates
Authors: Alay J. L. , Vandervorst W. 
Published: December 2004

AbstractXPS analysis was used to characterize Si (100) targets bombarded with an O2+ beam with energies ranging between 5.00 and 0.50 keV and incident angles between 0° and 75°. In this energy range and at normal incidence a homogeneous SiO2 layer is built up in a sequential suboxide replacement mechanism, while for bombardments at 5.00 keV and incident angles between 28° and 55° only a heterogeneous layer is formed. The latter contain elemental silicon, evenly spread in the altered layer, and all possible oxidized chemical states. For bombardments at high glancing angles (55°–75°) only a few suboxides are observed. Finally, a linear enhancement for the Si+ secondary ion yield w.r.t. the Si4+ relative concentration is found, except for very high Si4+ level concentrations where a strong non‐linear increase takes place.
Use of Si 2p x‐ray photoelectron diffraction as a test of epitaxial thin film growth by Si evaporation on Si(001)
Authors: Kubler L. , Lutz F. , Bischoff J. L. , Bolmont D. 
Published: December 2004

AbstractClean Si(001) surfaces are crystallographically characterized by x‐ray photoelectron diffraction (XPD). The anisotropic core level electron emission in the space, due to forward scattering mainly in the direction of the internuclear axes, is given by polar and azimuthal scans of the Si 2p core level intensities I(θ) and I(θ) in some particular high‐symmetry space directions. As an ilustration we apply this technique to a study of the homoepitaxial growth of thin (∼200 Å) evaporated silicon epilayers. Particular attention is paid to comparison of the epitaxy temperature dependence where the amorphous‐crystalline transition occurs by varying either the substrate temperature Ts at which the evaporation is done of the annealing temperature TA after a room temperature evaporation (solid phase epitaxy). We also suggest using the anisotropy factor deduced from the XPD patterns in oder to get information about the epitaxy quality.
Surface characterization and electrochemical behaviour of nitrogen‐ and carbon‐implanted titanium
Authors: Heide N. , Siemensmeyer B. , Schultze J. W. 
Published: December 2004

AbstractOwing to their combination of metallic and covalent properties, TiN and TiC are used as coating materials. In this work thin layers (layer thickness about 10 nm) of TiN and TiC were prepared by low‐energy ion implantation (3 keV N2+, 4 keV C2H4+) into Ti. The change in surface composition as a function of ion dose was followed by XPS. The electrochemical behaviour was studied in an electrochemical cell attached to the surface equipment; therefore no surface oxidation due to air contact took place. TiN and TiC revealed a stability up to 1.5 and 1.0 V respectively. Above these potentials oxidation to TiO2 and N2 in the case of TiN and to TiO2, CO2 and CO in the case of TiC occurred. The gaseous oxidation products were dissolved in the oxide layer and influenced its properties.
Multifactorial control of pituitary hormone secretion: The “Wheels” of the brain
Authors: Jacobowitz David M. 
Published: January 2005

AbstractAn attempt is made to deal with the complexity of the nerve fibers in the median eminence. Visual aids are presented in the shape of “wheels” that depict a dynamic interplay of neurochemicals which result in the release of hormones from the anterior pituitary gland. The multiplicity of neurochemicals in the median eminence is perceived to be responsible for the integrated control of pituitary hormone releasing factors.
Heterogeneity of motilin immunoreactivity in mammalian tissue
Authors: Nilaver Gajanan , Beinfeld Margery C. , Bond Chris T. , Daikh David , Godfrey Bruce , Adelman John P. 
Published: January 2005

AbstractMotilin is a 22 amino acid peptide first isolated and sequenced from porcine gut. The use of antisera directed to the synthetic porcine gut motilin sequence has produced conflicting results as to regional distribution and histological localization of motilin in mammalian brain and gut. Motilin immunoreactivity has been detected (by RIA) in brain regions where no immunostaining is discernible. Variations in the patterns of staining are also observed with different antisera. These discrepancies have been explained by postulating species‐, tissue‐, and region‐specific variations in peptide immunoreactivity, and variable cross reactivities of the independent antisera with these forms. The use of cloned porcine cDNA encoding gut prepromotilin in Northern blot analysis of brain regions expressing motilin‐like immunoreactivity has also failed to reveal a homologous message, questioning the true nature of the immunoreactive material in the brain. Physiological studies, however, have suggested central roles for motilin in a variety of CNS (feeding behavior, bladder control, cerebral and brain stem modulation, pituitary growth hormone release) and gastrointestinal (gastric emptying, intestinal motility) functions. The motilin immunoreactive material detected in brain may be encoded by a distinct non‐homologous gene, and still share amino acid homologies with the motilin sequence. Molecular biological characterization of the cell systems which contain motilin and motilin‐like immunoreactivity should allow a better definition of their roles in these tissues.