bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rubber modified epoxy resin. III: Reaction injection molding process
Authors: Kim Dae Su , Kim Sung Chul 
Published: December 2004

AbstractReaction injection molding of amine terminated butadiene acrylonitrile copolymer (ATBN) modified epoxy resin was investigated through computer simulation and experiment. The epoxy system composed of diglycidyl ether of bisphenol A (DGEBA) and triethylene tetramine (TETA) was employed since this system indicated a relatively high reaction rate. The coupled balance equations of momentum, chemical species, and energy within the disc‐type mold cavity were solved using finite difference techniques. The predicted temperature and conversion profiles within the mold were compared to experimental results. The domain correlation length data calculated from the simulation model were compared with the results of SEM micrographs. A moldability analysis was performed to find the optimum molding conditions. The moldability window decreased as the mold thickness was increased.
Analysis of shrinkage by dual kriging for filled and unfilled polypropylene molded parts
Authors: Mamat A. , Trochu T. F. , Sanschagrin B. 
Published: December 2004

AbstractThis paper examines, through holding pressure, packing time, melt temperature, mold temperature and distance from the gate, the effect of molding conditins on the shrinkage of polypropylene and 40% calcium carbonate (CaCO3) filled polypropylene. The shrinkage longitudinal and transvrse to the flow direction were determined using a 127 × 76 × 4 mm thick plaque with a film gate. Marks were made ont he mold cavity to measure shrinkage at various distances from the gate. The results show that holding pressure and packing time are the most significant parameters. Cooling runners, however, could significantly influence local shrinkage values. Calcium carbonate reduces the shrinkage anisotropy as well as the cycle time of the molded parts. Shrinkage models have been developed using dual kriging statistical interpolation techniques and show an excellent fit with experimetnal data.
Origin of the intermediate damping peak in microlayer composites
Authors: Nazarenko S. , Haderski D. , Hiltner A. , Baer E. 
Published: December 2004

AbstractA comparison of glass transition temperatures measured by differential scaning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) was made using mi9crolayer composites with many alternating layers of two polymers. What appeared to be a third transition at a temperature intermediate between the glass transitions of the two components was observ ed in DMTA but not DSC. The mechanical orgin of this intermediate damping peak in the layered composites was established. The viscoelastic properties of each polymer were modelled by a spring and dashpot in series, and the composite as a parallel arrangement of two Maxwell elements. It was shown that an anomalous damping peak can appear between the glass transition temperatures when the modulus of the composite can not drop below the modulus of the glassy layers, although the viscosity of the composite continues to be defined by the viscosity of the rubbery layers in this temperature range. The intermediate damping peak may be a general feature in the dynamic mechanical behavior of co‐continuous multiphase systems including polymer blends and continuous fiber composites.
The hybrid FEM/FDM computer model for analysis of themeteirng section of a single‐screw extruder
Authors: Chang Rong‐Yeu , Lin Kuen‐Jang 
Published: December 2004

AbstractA hybrid FEM/FEM computer model was employed n this studyfor simulating the non‐newtonian, nonisothermal polymr melt fielt in the inetering section of a single‐screw extruder. The pressure distribution in the screw surface was obtained by solving the generalized Reynolds equation. Instead of using the energy equation in Eulerian frame, a Lagrangian expression ws involved for stabilizing the numerical scheme. The temperature profiles wee obtained by finite difference discretizaton for the energy equation in such element. The screw surface with the screw channels and the flight lands could be modeled as a surface divided into small shell elements. To demonstrate aplicability, the results provided by the hybrid FEM/FDM were found to be similar to those of the 2D FDM for the trhermally developing flow, through Fenner's example. It can also ilustrate the leakage flow and the cross‐channel effect in the screw pumping problem. The results from the Hybrid FEM/FDM revealed that if the clearance becomes too large, the volumetric flow rate would considerably decrease and the exist melt temperature would increase. In addtion, when the clearance is close to the normal design clearance, the leakage flow through the flight lands was found to be small. These computational results were observed to correlate with those of other experimental studies. Finally, the hybrid FEM/FDM approach can in principle be extended to the non‐Newtonian, nonisothermal flow in a complex screw surface such as the barrier screw and the Maddock mixing head.
Assessment of residual stresses during cure and cooling of epoxy resins
Authors: Wang Hong‐Bing , Yang Yu‐Geng , Yu Hui‐Hong , Sun Wei‐Ming , Zhang Ying‐Hua , Zhou Hong‐Wei 
Published: December 2004

AbstractA new stress monitoring technique, a stress‐tracking device, is described here. It has been used to study some important properties of epoxy resin. Residual stresses, including a curing shrinkage stress and a cooling shrinkage stress, were measured automatically and continuously during curing and cooling. Simultaneously, information such as an apparent gelation time and glass transition temperature were obtained directly during the experiment. These epoxy resin properties were related to the extent of cure. Varying cure temperature produced changes of cure behavior, which resulted in different residual stresses.
Creep analysis of thermiplastics using stress relaxation data
Authors: Grzywinski G. G. , Woodford D. A. 
Published: December 2004

AbstractOne of the major factors limiting the use of thermoplastics in engineeing applications is the inadequacy of existing design data. Much of the data do not span appropriate ranges of stress, strain, time, or temperature. This study addresses the need to develop an accelerated method for generating long‐time design data to support the innovative use of engineering thermoplastics. In particular, stress relaxation tests (SRT) were performed on polycarbonate (PC) and midified poly(phenylene oxide)(PPO), and used to generate time‐dependent design data through the short‐time measurement of the material's current state without dependence on elastic modulus. The test results and analyses reported here indicate the SRT method to be an efficeint means of generating accurate and repeatable creep and secant modulus data which may be directly used in design. Therefore, SRT shows great potential both as a design parameter development tool, and as a quality control instrumetn for assessing batch‐to‐batch variability.
Thin‐film thermoplastic‐metal joining process for titanium to poly(etherketoneetherketoneketone)
Authors: Ramani Karthik , Tagle John , Nazre Ajit , Swarts Dale , Lin Steve 
Published: December 2004

AbstractThe processing of high temperture thermoplastic polymers as a hot melt adhesive is one means of joining thermoplastics to metals. The presetn study establishes the role of processing in thermoplastic joining of a titanium alloy (Ti‐6A1‐4V) using thin flim poly(etherketoneetherketoneketone) (PEKEKK). A design of expriments (DOE) was performed to determine the effects of the soak above melt temperature (Tm = 380°C), hold at the isothermal recrystallizztion temeprature (Tiso = ∼ 340°C) and cooling rates on the joint strength, Extended soak times are required to remove the residual spherulitic crystallinity in the polymeric adhesive. Whit the elimination of the residual crystallinity, high‐strength transcrystalline regions are enhanced at the polymer‐metal interface during the hold time at Tiso and during cooling to ambient temperature. Average tensile strengths of 137 MPa were achieved, exceeding the bulk polymer tensile strength of 118 MPa by 16%, X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) show that extended soak times above Tm led to excessive polymer squeeze‐out, resulting int he creation of strength‐reducing shrink voids or unwetted regions. As a result, the failue mode of the joint, which was normally cohesive for high‐strength joints, became a mix of cohesive and adhesive in parts with excessive polymer squeeze out.
Wettability and Dyeability Modulation of Poly(ethylene terephthalate) Fibers through Cold SF6 Plasma Treatment
Authors: Barni Ruggero , Riccardi Claudia , Selli Elena , Massafra Maria Rosaria , Marcandalli Bruno , Orsini Francesco , Poletti Giulio , Meda Laura 
Published: December 2004

AbstractSummary: Surface modification induced on poly(ethylene terephthalate) (PET) fibers by cold SF6 plasma treatment has been investigated systematically as a function of plasma device parameters. The observed wettability modifications of fibers plasma‐treated under different operating conditions were correlated to their dyeability modifications and to the changes in surface chemical composition, determined by X‐ray Photoelectron Spectroscopy (XPS), and topography, investigated by atomic force microscopy (AFM). Optical emission spectra from the SF6 plasma at different pressures gave information on its content of fluorine atoms. A striking transition was observed between the increased hydrophilicity and high dyeability, imparted by plasma treatment at low pressure (<0.2 mbar), mainly as a consequence of surface etching and surface activation, and the increased hydrophobicity, imparted by plasma treatment in the higher pressure regime (0.2–0.4 mbar), consequent to extended surface fluorination.Water droplet adsorption time on PET fabrics, plasma‐treated at different pressures.imageWater droplet adsorption time on PET fabrics, plasma‐treated at different pressures.
Forward Scattering Signature of a Spherical Particle Crossing a Laser Beam out of the Beam Waist
Authors: Chevaillier Jean‐Philippe , Fabre Jean , Hamelin Patrice , Lense Jean‐Loup 
Published: December 2004

AbstractWhen a particle crosses a laser beam out of the focal plane, the light attenuation signal occuring on the beam axis contains some information regarding the particle size and trajectory.These attenuation signatures are analysed and predicted with a simplified model based on Fraunhofer diffraction. Numerical and experimental results are found to be in good agreement.A modified laser Doppler velocimeter using this sizing method is able to perform simulataneous measurement of size and velocity of spherical particle in the range 10 μm–500 μm.
The Phase‐Doppler‐Difference‐Method, a New Laser‐Doppler Technique for Simultaneous Size and Velocity Measurements. Part 1: Description of the method
Authors: Bauckhage Klaus 
Published: December 2004

AbstractIn the wide field of fluid mechanics and multiphase flows, particle characterization plays an important role for massmomentum‐ and energy‐balances. Using the phase‐Doppler‐difference method for absolute measurements of the particle sizes and velocities from these data also predictions of the local particle fluxes and the particles' kinetic energy fluxes are possible. A description of the method will be given and the required optical and electronical equipment for these measurements and for the appropriate data presentation, will be discussed.
In‐line Particle Size Analysis in the fines outlet of an air classifier
Authors: Heuer Michael , Schwechten Dieter 
Published: December 2004

AbstractLaser diffraction (LD), with reference to the analysis time, is highly advantageous for the automation of particle size analysis. The high measuring frequencies alloy quasi‐continous measuring operation. The fineness values obtained form the particle size distribution (PSD) can be transformed into electrical signals for automatic process control.For industrial purposes, an encapsulated measuring cell was developed where the laser beam penetrates the dispersed fines stream via two optical windows. Thus, hazardous materials can also be measured, specifically pharmaceutical or chemical products, or applications requiring explosion‐proof plant design are possible. Great efforts had to be made to keep the inner side of the windows clean form product dust. Ultimately, batches running for more than 8 h could be analysed continuously without any contamination of the windows. For the PSD measurements, a standard LD instrument was used with a measuring range of 0.5/0.9–175 μm.As product fineness is monitored continuously in‐stream, and virtually without delay, any changes in the fineness during classifier operation can be detected immediately. On the one hand, this opens up a new field for studies of classifier performance. On the other, immediate quality control of even very small batches is possible during the micronization process. The results demonstrate very clearly, for example, the importance of controlling the feed rate to the classifier. Therefore, fineness control by means of this in‐line technique gives superior advantages for direct adjustment of the classifier speed.
Experimental Determination of the Transfer Function of a Differential Mobility Analyzer (DMA) in the nanometer size range
Authors: Hummes Detlef , Neumann Siegfried , Fissan Heinz , Stratmann Frank 
Published: December 2004

AbstractThis paper describes the evaluation of the transfer function for the TSI‐short differential mobility analyzer (DMA) in the nanometer particle size rang. The TSI‐short DMA is identical with the TSI‐long DMA (Model 3071) but has shortened inner and outer electrodes and the insulator material Teflon was replaced by black Delin. The DMA transfer function was determined by operating two identical DMAs in series. The DMA was investigated at a sheath to aerosol flow rate ratio of between 10 and 1. Usually for particles above 50 nm the parameters of the assumed triangular transfer function, i.e. height and half‐width, approach the ideal values, which depend only on the flow ratio. For particle size below 50 nm the height decreases from 0.9 at 50 nm to 0.18 at 5 nm. The half‐width increase from the ideal value 0.1 to about 0.17. The observed changes of the transfer function are due to diffusional effects resulting in losses mainly in the inlet and outlet and also broadening of the aerosol stream inside the DMA. The determined transfer functions were also compared with transfer functions calculated using a theoretical model. The agreement proved to be satisfactory. The half‐widths and the transmission efficiencies of the conventional TSI‐DMA (Model 3071), TSI‐short with Teflon and also black Delin insulator as a function of particle size are compared to demonstrate the improvements in performance.
Ostwald Ripening of Concentrated Alkane Emulsions: A preliminary report
Authors: Bremer Leon , De Nijs Bruno , Deriemaeker Luc , Finsy Robert , Geladé Erik , Joosten Jacques 
Published: December 2004

AbstractFiber optic dynamic light scattering (FODLS) was used to study the kinetics of aging processes in emulsions of n‐alkanes stabilized by a surfactant. The method is particularly useful for this purpose because it permits measurements in concentrated emulsions. Complications that may occur in traditional DLS due to the extreme dilution, such as solubilization of the particles in the medium, can be easily avoided in this way. The experimental results show that the main aging process is Ostwald ripening. The results are in agreement with theoretical predictions based on the Lifshitz‐Slyozov‐Wagner (LSW) theory as far as it concerns the relation between the molecular solubility of the n‐alkanes (in the aqueous phase) and the Ostwald ripening rate. This illustrates that the main rate‐determining factor is the molecular diffusion of the alkane molecules through the continuous (aqueous) phase. The Ostwald ripening rate is affected by the concentration of surfactant but in all situations is higher than expected from LSW theory.
The Use of Lead in Explosive Cladding
Authors: Prümmer R. 
Published: December 2004

AbstractLead has for a long time not been employed in explosive cladding because its velocity of sound (c = 1250 m/s) is very low compared to the detonation velocities of conventional explosives (vD ≈ 3000 m/s). I t is shown that by using a carbonite explosive, which has a detonation velocity of less than 1500 m/s, useful explosive cladding can be achieved. The relationship between quantity of explosive and cladding parameters such as angle of collision and plate velocity vp is determined. The interface between lead‐copper and lead‐steel claddings is wave‐like. The wavelength depends on the angle of collision and is larger for lead‐copper claddings than for those between lead and steel.
Electrical Conduction in Ammonium Perchlorate
Authors: Pai Verneker V. R. , Mohan V. Krishna 
Published: December 2004

AbstractElectrical conductivity studies on pure ammonium perchlorate, AP, and AP doped with sulphate ions have been carried out. The results indicate that the conduction is ionic in nature. Together with the observations made on the effect of electric field on the thermal decomposition of AP, the results of the present study establish that perchlorate ion is the major charge carrying species. The enthalpy for migration of defects has been found to be 0.8 eV, and the enthalpy for the formation of defects to be 1.2 eV.
Recovery of Organic Values from TNT Purification Waste Water
Authors: Gilbert E. E. 
Published: December 2004

AbstractPure sodium 2,4‐dinitrotoluene‐3‐sulfonate and ‐5‐sulfonate were prepared, and a procedure was developed for their extraction (as a mixture) from TNT purification waste water (‘red water’). Reactions of the sulfonates were studied, with special emphasis on possible direct and indirect methods for desulfonating them to 2,4‐DNT. Other reactions studied included reduction of one or both nitro groups, followed by desulfonation, yielding 2‐amino‐4‐nitrotoluene and 2,4‐diamino‐toluene, respectively, and replacement of the sulfonate group by chlorine, hydroxyl, and various substituted amino groups. Most of these reactions with the pure sulfonates were also applied to the corresponding TNT isomers, and in some cases directly to stabilized red water.
Laboratory and Field Investigations of Shotfiring Fumes of mining explosives in Poland
Authors: Cybulska R. , Sobala J. 
Published: December 2004

AbstractDetonation products of basic explosives like ammonium nitrate, permitted Metanit D 2 and nitroglycerin‐Barbaryt A were analysed for O2, CO2, CO, CH4, H2, NO2 and N2 and the shotfiring properties studied. The tests were carried out under laboratory conditions and in shotholes drilled underground in the mine, in coal and in stone.
Die in der Bundesrepublik Deutschland benutzte Methode zur Bestimmung der toxischen Bestandteile der Sprengschwaden
Authors: Eitz E. , Zimmermann R. 
Published: December 2004

AbstractBei der Zulassungsprüfung von Bergbausprengstoffen werden Sprengschwaden mit einer praxisnahen Sprenganordnung in einer Gesteinskammer der Versuchsgrube Tremonia erzeugt. Der Gehalt der Sprengschwaden an den toxischen Bestandteilen Kohlenmonoxid und nitrose Gase wird nach vorgeschriebenen Probenahme‐ und Analysenverfahren ermittelt. Die Einzelheiten der Methode werden beschrieben. Zusätzlich wird über Untersuchungen zur Erzeugung von praxisähnlichen Sprengschwaden in einer Laboratoriumsanordnung berichtet.
Eine Methode zur Prüfung der Detonationsfähigkeit von Slurries
Authors: Klünsch M. , Lingens P. 
Published: December 2004

AbstractEs wut Je eine Prüfmethode für die Detonationsfahigkeit von Sprengschlammen entwickelt, die sowohl die Bestimmung des kritischen Durchmessers als auch der kritischen Zündladung erlaubt. Außerdem ermöglicht diese Methode eine Brisanzmessung zur Unterscheidung unterschiedlicher Sprengschlamme. Die Prufmethode beruht auf dem Beschuß einer Stahlplatte. Der Sprengstoff befindet sich in einem Stahlrohr, das senkrecht auf die Beschußplatte gestellt wird. Der Sprengstoff wird mit Hilfe einer Verstärkerladung von oben her gezündet. Der Eindruck oder Durchschlag auf der Stahlplatte erlaubt eine Beurteilung des geprüften Sprengschlammes. Die Prufmethode macht es moglich, Sprengschlamme miteinander zu vergleichen und für den Einsatz in der Praxis auszuwählen.
Erfahrungen mit Methoden zur Einordnung der Deflagrationsfestigkeit von Wettersprengstoffen
Authors: Zimmermann R. 
Published: December 2004

AbstractZur Ermittlung der Deflagrationsfestigkeit von Wettersprengstoffen höherer Sicherheitsklassen wird in der Bundesrepublik Deutschland eine Variante des von Audibert und Delmas vorgeschlagenen Verfahrens benutzt (geschlossenes Stahlrohr mit Entlastungsdüse). Dabei wird die Deflagrationsneigung des Sprengstoffs unter Druck‐ und Wärmestau in einer Kohlenstaubumgebung bestimmt. Die Einleitung der Deflagration erfolgt durch einen definierten Anzündsatz. Die Druck‐ und Wärmestau‐Bedingungen werden durch eine Düse wählbaren Durchmessers vorgegeben. Bei den nach diesem Verfahren geprüften und zugelassenen Wettersprengstoffen ist in der Praxis seit 1972 kein Fall einer Deflagration bekannt geworden.
Génération et Repérage d'un Signal Lumineux Bref
Authors: Presles H. N. , Bouriannes R. , Brochet C. 
Published: December 2004

AbstractRésuméOn présente une méthode simple de génération et d repérage d'un signal lumineux. Ce signal est obtenu en ionisant un petit volume d'argon par une onde de choc forte. Il est repéré dans le temps à l'aide d'un signal électrique provoqué par la polarisation d'un matériqu diélectrique traversé par cete même onde de choc. Ce dispositif est utilisé pour déterminer le temps de retard d'un pyromètre optique à court temps d réponse.
The assay of hydrazine mononitrate as a base in acetic acid
Authors: Selig W. , Bissell Eugene R. 
Published: December 2004

AbstractHydrazine mononitrate has been determined as a base by non‐aqueous titration in glacial acetic acid. The titrant was 0.05 N perchloric acid in glacial acetic acid which must be prepared without acetic anhydride. Small amounts of water increase the solubility of hydrazine nitrate, but reduce the sensitivity of the method.
Detonation chemistry: Diffusion control in non‐ideal explosives
Authors: McGuire R. R. , Ornellas D. L. , Akst I. B. 
Published: December 2004

AbstractThe performance of an explosive is a function of both the peak energy released near the detonation front, and the remainder of the energy that is released during the Taylor wave. The relative partitioning of energy between the front and the expansion, and the rate of energy release in the latter, may be controlled by either chemical kinetic or diffusion processes. Detonation calorimetry has been the principal experimental technique used to investigate these processes. Both the total energy release, and the quantitative analysis of the detonation products at a point or region on the expansion isentrope have been determined for formulations of ammonium nitrate (AN) and TNT in which both the composition and particle size of the AN have been varied. Isotopic labeling of selected explosives has also been used to give further insight into the reactions taking place in or near the reaction zone. Similar experiments have been performed in an ideal, homogeneous explosive.