bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the transesterification of polycarbonate/poly(ethylene terephthalate) blends. II: Effect of transesterification on the compatibility and crystallization behaviour of the blends
Authors: Zheng Wen‐ge , Qi Zong‐neng , Wang Fu‐song 
Published: May 2005

AbstractThe effect of transesterification on the compatibility of polycarbonate poly(ethylene terephthalate) (PC/PET) blends and the crystallization and melting behaviour of PET was studied. The results show that with increase of the reaction extent, the compatibility of the blends was enhanced during melt‐processing, from completely incompatible to partially compatible, then to complete compatibility. In addition, with the increase of reaction extent, the crystallization ability and crystallinity of PET decreased. A new endotherm peak was discerned in DSC thermograms and its position and peak area were closely related to the reaction conditions, which was explained by the changes in the crystalline regions in the PC/PET blends. The effect of transesterification on the multiple melting behaviour of PET in PC/PET blends is also discussed.
Specific interaction between water‐soluble phospholipid polymer and liposome
Authors: Ishihara Kazuhiko , Nakabayashi Nobuo 
Published: May 2005

AbstractA water‐soluble polymer having both a phospholipid polar group and an azobenzene group, poly(2‐methacryloyloxyethyl phosphorylcholine‐co‐p‐phenylazoacrylanilide) (poly(MPC‐co‐PAAn)) was synthesized and the interaction between the liposome of the phospholipid was investigated in comparison with other water‐soluble azoaromatic polymers. When the poly(MPC‐co‐PAAn) was incubated with dipalmitoylphosphatidylcholine (DPPC) lipo‐somes above these gel‐liquid crystalline temperatures, an electronic spectrum of azobenzene moiety, which is a hydrophobic probe, showed that the a copolymer chain exists under nonpolar circumstances. Thus, poly(MPC‐co‐PAAn) interacts with DPPC liposomes. On the other hand, other copolymers do not interact with the liposomes. Moreover, heat of the gel‐liquid crystalline transition of DPPC liposomes was increased by the presence of poly(MPC‐co‐PAAn). These findings clearly indicate that the poly(MPC‐co‐PAAn) has an affinity to the DPPC liposomes and hybridizes with liposomes based on the phospholipid polar group of the copolymer.
Vinylphosphonic esters as end‐capping agents in group transfer polymerization
Authors: Hertler Walter R. 
Published: May 2005

AbstractDiethyl vinylphosphonate does not undergo group transfer polymerization (GTP), but does react with the silyl ketene acetal end group of PMMA prepared by GTP to give α‐(2‐diethoxyphosphinylethyl) PMMA. Copolymerization of MMA and small amounts of diethyl vinylphosphonate led to copolymer. The telechelic PMMA diphosphonic acid, α‐(2‐dihydroxyphosphinylethyl) ω‐dihydroxyphosphinylPMMA, was synthesized by initiation of GTP of MMA with diethyl 3‐methoxy‐3‐trimethylsiloxy‐2‐propene‐1‐phosphonate, followed by termination with diethyl vinylphosphonate, silylation of the phosphonic ester with bromotrimethylsilane, and hydrolysis. Reaction of living poly (methyl methacrylateco‐n‐butyl methacrylate), prepared by GTP, with bis (trimethylsilyl) vinylphosphonate followed by hydrolysis gave α‐(2‐dihydroxyphosphinylethyl) poly (methyl methacrylateco‐n‐butyl methacrylate).
New telechelic polymers and sequential copolymers by polyfunctional initiator‐transfer agents (inifers) LVII. Chlorine telechelic poly(p‐chlorostyrene)
Authors: Zsuga M. , Kennedy J. P. 
Published: May 2005

AbstractThe polymerization of p‐chlorostyrene (pClSt) under carbocationic conditions has been investigated. The use of binifers 1,4‐di(2‐chloro‐2‐propyl) benzene (pDCC) and 1,3‐di(2‐chloro‐2‐propyl)‐5‐tert‐butylbenzene (m‐tBuDCC) in conjunction with BCl3 coinitiator in CH3Cl diluent at −60 and −35°C give α,ω‐di‐benzylic chlorine‐capped polymer sClPpClStCls. According to kinetic investigations the inifer mechanism is operative and both binifers are efficient in controlling the end structures, molecular weights, and to a certain extent molecular weight distributions (MWD). Strong circumstantial evidences have been generated to demonstrate the satisfactory synthesis of sClPpClStCls and the absence of indanyl end‐groups, i.e., structural considerations, linearity of inifer plots, quantitative Cl end‐group microanalysis, FTIR spectroscopy, and blocking experiments. The latter involved the blocking of THF from the sec‐benzylic chlorine end‐groups by AgPF6 and thus led to the synthesis of a new triblock copolymer PTHF‐b‐PpClSt‐b‐PTHF. Interestingly, the isotactic content (mm triads and mmmm pentads) of PpClSt is significantly higher than that of polymer prepared by free‐radical induced polymerization. The Tg of a PpClSt of M̄n = 5700 g/mol was 123°C.
Polyesters, polyurethanes, and epoxy resin derived from 2,2′‐(1,4‐phenylenedivinylene)bis‐5‐hydroxypyridine
Authors: Mikroyannidis John A. 
Published: May 2005

Abstract2,2′‐(1,4‐Phenylenedivinylene)bis‐5‐hydroxypyridine (PBHP) was used as a starting material for preparing new polyesters and polyurethanes as well as a diepoxide‐bearing styrylpyridine segments. The diesters were prepared by reacting PBHP with terephthaloyl or adipoyl dichloride utilizing the interfacial polycondensation method. The diesters were prepared from the reaction of PBHP with tolylene diisocyanate or methylenebis(4‐phenylisocyanate). In addition, a model diester and diurethane were synthesized by reacting PBHP with benzoyl chloride and phenyl isocyanate, respectively. Both model compounds and polymers were characterized by IR and 1H‐NMR spectroscopy, as well as by DTA and TGA. A diepoxide was also prepared from the reaction of PBHP with epichlorohydrin which was polymerized in the presence of 4,4′‐diaminodiphenylsulfone. The polyester derived from PBHP and terephthaloyl dichloride was the most thermostable polymer obtained. It was stable in N2 up to 355°C and afforded an anaerobic char yield of 59% at 800°C. The thermal stabilities of polymers were improved by curing.
Brittle fracture of entangled polymers
Authors: Mikos Antonios G. , Peppas Nikolaos A. 
Published: May 2005

AbstractA stochastic model is presented to calculate the number of chain segments entangled about a unit plane when the segment length is a stochastic variable. This crossing density to which the brittle fracture energy and the critical strength of entangled polymers scale is a function of the number of moles of entanglement network strands per unit volume and the mesh size of the entanglement network. Experimental results of the molecular weight dependence of the fracture energy and strength validate the theoretical predictions.
Third‐order interaction approximation for linear polymer chains
Authors: Xu Jianmin , Song Xubing , Zhou Zhiping , Yan Deyue 
Published: May 2005

AbstractThird‐order interactions imposed by a pair of atoms separated by five bonds are taken into account in computations of the mean‐square end‐to‐end distance and the mean‐square radius of gyration for linear polymer chains. The statistical weight matrices are established on the basis of the rotational isomeric state model. The conformational energy of n‐hexane is calculated as a function of the CC bond rotation angles. The third‐order interaction energy is obtained by comparison with that of n‐pentane. The characteristic ratio of polymethylene is 6.6 in the third‐order interaction approximation, which is in agreement with experimental data.
Multifractal Description of a Rugged Fineparticle Profile
Authors: Kaye Brian H. 
Published: May 2005

AbstractMandelbrot has extended the concept of classical dimensional description of physical systems to include fractional values which describe the ruggedness of a structure. Thus if one has a dimension of 1.2 one knows that one is dealing with a line which fills space more efficiently than a line which has dimension of 1.1. A mathematical curve which exhibits ideal fractal structure has the same appearance when viewed at any level of scrutiny. Kaye and co‐workers applied the concept of fractal mathematics to the description of the boundaries of fineparticle profiles. As demonstrated in this communication a natural fractal boundary in contrast with an ideal fractal can exhibit different fractal structures over different ranges of scrutiny. As a consequence one should always report the scale of scrutiny employed when examining the fractal structure of natural boundaries. Data is presented demonstrating the fractal/euclidean boundary structure manifest by aluminum shot fineparticles examined at various levels of scrutiny. The relationship between fractal descriptors of fineparticle boundaries and the Fourier analysis of geometric signature waveforms for describing the structure of fineparticles is explored. Data presented by Flook on the physical significance of the various co‐efficients of a Fourier analysis of a signature waveform is correlated with the fractal description of the ruggedness of a profile.
Sampling Powders for Shape Description
Authors: Hawkins Arthur E. , Davies Kenneth W. 
Published: May 2005

AbstractFor some time studies have been made relating the values obtained from simple shape description to bulk powder properties. More recently the detailed mathematical description of particle outline has become possible and quite powerful techniques have been developed. These techniques may be used for the regeneration by computer of the shape and, more importantly, for studies relating shape to individual particle behaviour and to bulk powder properties. Quite inadequate attention has been directed to the task of obtaining from the laboratory sample of the bulk powder a representative sample of shapes without bias. In this communication the considerations to be included in the sampling procedure are reviewed and a possible solution to the problems posed is presented.
Response of the Coulter Counter® Model ZM to Spheres
Authors: Harfield John G. , Wharton R. Tony , Lines Roy W. 
Published: May 2005

AbstractMost existing theories of the response of electrical sensing zone particle size analysers, for instance of the type Coulter Counter®, predict that a significant deviation from sizing linearity will occur at and above some 40% of the aperture diameter. Practical experience, at least for the only test models available ‐ latex spheres ‐ shows that this is not the case in practice. Linear particle response up to 80% of the aperture diameter has been established, confirming the prediction recently made by Scarlett in a new response theory.
Comparison of Techniques for Measuring the Size of Fine non‐spherical particles
Authors: Seville Jonathan P. K. , Coury José R. , Ghadiri Mojtaba , Clift Roland 
Published: May 2005

AbstractThree general types of commercial particle sizing instruments have been tested with redispersed fly ash and devolatilised coal char in the size range 0.5 to 5 μm. Results are compared with volume‐equivalent diameters obtained by Coulter Counter. Single‐particle light‐scattering counters are found to oversize fly ash, primarily because of the irregular particle shape, but generally to undersize the strongly absorbing char particles. The Malvern sizer, based on Fraunhofer diffraction analysis, grossly oversizes fly ash dispersed in water, probably because most of the particles are too small for the Fraunhofer approximation to be valid; results for carbon char are closer to the expected values, although results for particles dispersed in air and in water show some disagreement. The Aerodynamic Particle Sizer undersizes irregular particles substantially, probably because of increased drag resulting from the irregular shape and tumbling motion of these particles.
Errors in the Determination of Particle Size Distributions Caused by coincidences in optical particle counters
Authors: Raasch Jürgen , Umhauer Heinz 
Published: May 2005

AbstractWhen performing particle size analysis by scattered light, coincidences in the measuring volume of optical particle counters not only cause too small a particle concentration to be measured, but also a size distribution to be obtained which is systematically shifted towards coarser particle sizes. It is pointed out in this paper how this shift can be precalculated when the true distribution is given. The results show under which conditions a correction of the measured distribution is indispensable.
The Role of Fractal Quantities, as Specific Surface and Tortuosities, for physical properties of porous media
Authors: Pape Hansgeorg , Riepe Lutz , Schopper Jürgen R. 
Published: May 2005

AbstractBesides the knowledge of material constants of the homogeneous phases of a disperse system, a good understanding of its geometrical properties is necessary for describing physical processes. In order to characterize the shape of the interface between solids and pore space with respect to the irregularities in all orders of magnitude, the fractal dimension has proved to be an informative parameter. By this study the theory of fractal dimensions, in three‐dimensional space originally limited to topological curves, surfaces and volumes, is extended into physical properties like specific surface, tortuosity, porosity and formation factor with “physical” dimensions −1 or 0 as an exponent of the unit of length. The typical properties of the true fractals are transferable to some of these derived parameters. This leads to power laws describing the dependence of the particular measure on the resolution length. With special models, which seem to be of widespread validity in nature, petrophysical considerations lead to further power laws for the rest of the physical parameters, dependent on discrete length parameters such as grain radius and pore radius. By determination of the exponents of such independent power laws, a better particle characterization is possible, as the fractal dimension of the surface alone may be misleading, especially when the grain size of the particles is not uniform.
Comminution of Irregularly Shaped Particles by Slow Compression: Interpretation of the size distributions of progeny particles as mixed distributions
Authors: Hanisch Jens , Schubert Heinrich 
Published: May 2005

AbstractThe evaluation of particle size distributions of comminution products often shows that the experimental distributions cannot be represented by one of the well‐known functions (GGS, RRSB, log‐normal distributions). Although in some cases a more or less satisfactory approximation to one of these functions can be made, a physically meaningful interpretation is generally impossible. Using the frequency curve, it can often be shown that mixed distributions, represented by several statistical assemblies, do exist. In this paper the progeny size distributions of quartzite formed by slow compression comminution of single grains and particle beds as well as of the comminution products of a roller mill are interpreted as superpositions of several statistical assemblies each of which can be represented by a truncated log‐normal distribution.
Representation and Evaluation of Particle Size Analysis Data
Authors: Leschonski Kurt 
Published: May 2005

AbstractWhile editing the first issues of Particle Characterization it has been recognized by the editors that the papers submitted differ widely in the representation of data and in the nomenclature chosen to characterize such common variables as particle size, different equivalent particle diameters, average particle sizes, cumulative and density values of a distribution etc. In oder to make papers published in this Journal more readily assimilable and graphs representing particle size analysis data instantly recognizable by using agreed upon standardized nomenclature the following paper has been submitted by one of the editors. It was first presented at the Harold Heywood Memorial Symposium, September 1974, at the University of Technology, Loughborough, U. K.
Correlation of Simultaneously Measured Droplet Sizes and Velocities in nozzle sprays
Authors: Bauckhage Klaus , Floegel Hans‐H. 
Published: May 2005

AbstractThe application of a new LDA method which simultaneously measures the size and velocity of small water droplets in the spray cone of a fan type water nozzle is described. As the phase difference between adjacent photomultipliers responding to signals from a fringe mode LDA is linearly proportional to the diameter of the spherical particle in the measuring volume, the new instrument allows, for long distances between the optical devices and the measuring volume in the spray, non‐invasive measurements and from these the correlation of size and velocity of the individual droplet in order to establish two‐dimensional distributions. From the new LDA instrument one receives definite information about the volume‐flow concentration in the measuring point of an enclosed flow situation.
The Determination of Particle Size Distribution Using Combined gravitational and centrifugal sedimentation analysis
Authors: Laapas Heikki R. , Lahtinen Ulla‐Riitta 
Published: May 2005

AbstractCombined gravitational and centrifugal sedimentation analysis was studied using a Sedigraph X‐ray sedimentometer and a Ladal pipette centrifuge. The test powders were talc, calcite and lead oxide. The purpose of the study was to examine the possibilities of extending the sedimentation analysis towards finer sizes by the use of centrifugal force. All the test samples could be analysed down to 0.04–0.05 μm by the combined sedimentation procedure with reasonable accuracy and the results were matched to give a uniform distribution. It was also shown to be preferable to present the size analysis data in a log‐probability scale, as it gives the means to easily distinguish materials with different particle size characteristics and to estimate the actual distribution by a statistical function.
Results Obtained with a New Instrument for the Measurement of particle size distributions from diffraction patterns
Authors: Heuer Michael , Leschonski Kurt 
Published: May 2005

AbstractFor several years the size distributions of particulate matter have increasingly been determined by using diffraction pattern analysis.In order to evaluate particle size distributions from the far field intensity distribution of light diffracted by a distribution of particles, a linear set of equations must be solved. Since, in many cases of application, conventional methods for solving linear sets of equations become unstable, the calculated particle size distribution may also be grossly in error. By applying special, known mathematical methods we succeeded in obtaining a parameterfree solution of the above problem.After a brief description of the mathematical method used, a diffraction pattern analyser will be presented as well as some experimental results obtained with it. The results obtained with aerosols and suspensions come from experiments performed with narrow‐sized latexes and mono‐ and bi‐modal particle size distributions of limestone and quartz.
Measurement of Particle Orientation Distribution by a Stereological Method
Authors: Kanatani Ken‐ichi 
Published: May 2005

AbstractPractical procedures are described for a stereological method which determines the spatial distribution of particle orientation from the distribution observed on cross sections. First, the two dimensional distribution of needle‐like particles is determined by counting the number of intersections with parallel probe lines. Next, the three dimensional distribution of needle‐like particles is determined by counting the number of intersections with a cutting plane. Then, the three dimensional distribution of disklike particles is determined by counting the number of intersections with a probe line. Finally, the distribution of disklike particles is determined by measuring the total length of the cross sections on a cutting plane.
The Influence of Particle Attrition on the Wall Friction Coefficient of a free flowing particulate solid
Authors: van den Bergh Wim J. B. , van Dalen G. , Scarlett Brian 
Published: May 2005

AbstractIn this paper a reciprocating shear cell, which has been developed to measure dynamic wall friction, is described. The cell has also been used to study the attrition behaviour of sand samples at the bounding wall. This attrition causes a considerable change in the angle of wall friction.
On Using Fourier Series in Characterizing Particle Shape
Authors: Bandemer Hans , Albrecht Matthias , Kraut Andre 
Published: May 2005

AbstractThis paper starts from the fact that the Fourier coefficients of the contour of a particle are commonly used to describe its shape, for example by Meloy's law of morphological coefficients. The authors point to the sensitivity of the Fourier coefficients of jump discontinuities of the contour or of one of its derivatives. Explicit formulae for this dependence are reported and are used to suggest a stochastic model, the sensitivity is demonstrated by two examples with calculated results.
Activation of Ultrafine particles by supersaturation in condensational process
Authors: Kousaka Yasuo , Okuyana Kikuo , Niida Tohru , Hosokawa Takahiro , Mimura Tadaaki 
Published: May 2005

AbstractThe Activation of ultrafine particles as the condensation nuclei, or heterogeneous nucleation of ultrafine particles, has been observed in various supersaturated vapors. Monodisperse NaCl, ZnCl2, Ag and silicon oil particles, 5–15 mm in diameter, are used as the condensation nuclei and water, hexanol, dibutyl phthalate (DBP) and di‐2‐ethyl‐hexyl sebacate (DEHS) are used as teh vapors. The supersaturated atmosphere is formed in the mixing type condensation nucleus counter (CNC) where a room temperature aerosol is mixed with warm air saturated by each vapor and the supersaturation ratio is controlled by changing the temperature of the saturated air. The number ratios of activated particles to total particles are observed at various supersaturation ratios. It is found that the activation of particles depends in a complicated manner on the combination of the substances of particles with condensing vapors, that is, activation in some particle‐vapor systems is explained by the Kelvin effect but not in others.
A Universal Aerosol Sampling Probe for High Efficiency Particle sampling from flowing gas streams
Authors: Liu Professor Benjamin Y. H. , Pui David Y. H. 
Published: May 2005

AbstractAn aerosol sampling inlet has been developed to collect representative samples from the flowing gas stream. The inlet is referred to as the “Universal Aerosol Sampling Probe” because it is capable of efficient sampling over a wide range of free stream velocity without the need to change either the probe tip or sampling flow rate. It is a multi‐nozzle device consisting of one or more outer nozzles to extract a sample isokinetically and decelerate it from the relatively high stream velocity to a relatively low velocity. An inner nozzle is then used to extract a representative particle sample for delivery to the impactor or other particle collectors placed downstream. The approach enables a representative particle sample to be extracted at a fixed flow rate, irrespective of the velocity of the gas stream in which the probe is placed. The theoretical considerations leading to the design of such a universal probe are described. It is followed by the description of an experimental evalution of a prototype device. Good agreement was found between the experimental results and the theoretical prediction.
The Development of a True Biaxial Shear Tester
Authors: Harder Joachim , Schwedes Jörg 
Published: May 2005

AbstractTo investigate the influence of the stress history on the yield limit a shear tester was developed, in which stresses or strains in x‐ and y‐direction can be applied independently of each other. Since there are no shear stresses on the boundary surfaces of the sample these stresses are principal stresses and the Mohr stress circles are known for each state of stress. First results from shear tests with limestone show a significant influence of the different ways of consolidation on the yield limit, i. e. the flow properties of a bulk solid will depend on the stress history. The flow function, however, which is essential for silo design, proves to be invariable of the stress history.