bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonuniform cooling in multifilament melt spinning of polypropylene fibers: Cooling air speed limits and fiber‐to‐fiber variations
Authors: Andreassen Erik , Myhre Ole Jan , Oldervoll Frøydis , Hinrichsen Einar L. , Grøstad Kristin , Braathen Marianne D. 
Published: April 2003

AbstractThe cooling of the spinning stage in a commercial compact‐spinning line has been studied. A rectangular fiber bundle is extruded from the spinneret and cooled by air entering from one side. The speed of the cooling air is considerably reduced through the fiber bundle. There are practical lower and upper limits for the cooling air entrance speed, corresponding to filament breakage at the leeward and windward sides, respectively. These limits are functions of the material and processing parameters. Due to the nonuniform cooling, fibers sampled at the windward side generally have higher molecular orientation, lower amorphous fraction, higher density, and higher tensile modulus and strength. For most combinations of spinning and material parameters, the structure is either bimodally oriented α‐crystalline or uniaxially oriented mesomorphic at all spinneret positions. Fibers with different structure types show opposite windward/leeward side trends with regard to local order and melting behavior. The structure may be mesomorphic at the leeward side and α‐crystalline at the windward side, if the average spin‐line stress is close to a critical value for orientation‐induced crystallization, and the air speed difference across the spinneret is large. The cooling air speed affects the spin‐line stress. Hence, the fiber‐to‐fiber variations due to nonuniform cooling are discussed in terms of the molecular orientation in the melt and the effective time available for arranging molecules into ordered structures. © 1995 John Wiley & Sons, Inc.
Properties of fatty‐acid esters of starch
Authors: Sagar Ambuj D. , Merrill Edward W. 
Published: April 2003

AbstractThis work examines the properties of starch esters for their possible application as environmentally degradable thermoplastics. The rheological, thermal, and mechanical properties of a series of fatty‐acid esters of high‐amylose starch (as well as the effects of adding plasticizer on some selected properties) were evaluated. The ester group acts like an internal plasticizer, with an increase in the size of the fatty‐acid chain, resulting in greater internal plasticization. This is reflected in the rheological and thermal measurements as well as in the mechanical properties. Overall, larger ester groups and the addition of external plasticizer make these starch‐based materials more processable and more ductile. However, comparing their properties and cost to commodity thermoplastics leads us to believe that their commercial applications are likely to be limited, at least in the near future. © 1995 John Wiley & Sons, Inc.
Specialty polymeric membranes. V. Selective permeation of carbon dioxide through synthetic polymeric membranes having 2‐(N,N‐dimethyl)aminoethoxycarbonyl moiety
Authors: Yoshikawa Masakazu , Fujimoto Kiyoshi , Kinugawa Hirokazu , Kitao Toshio , Kamiya Yoshinori , Ogata Naoya 
Published: April 2003

AbstractPermeation of CO2 was investigated by using synthetic polymeric membranes having a tertiary amine moiety, 2‐(N,N‐dimethyl)aminoethoxycarbonyl moiety. Permselectivity of the present membranes towards CO2 was achieved. Through poly{2‐(N,N‐dimethyl)aminoethyl methacrylate‐co‐acrylonitrile} (DMAEMA/AN‐199) membrane, where DMAEMA mol fraction was 0.199, the separation factor towards CO2 for CO2/N2 separation ranged from 60 to 90, ranging in the CO2 partial pressure in the feed gas from 61 to 3.6 cmHg. © 1995 John Wiley & Sons, Inc.
Maleated polyisobutylene: A novel toughener for unsaturated polyester resins
Authors: Abbate M. , Martuscelli E. , Musto P. , Ragosta G. , Scarinzi G. 
Published: April 2003

AbstractA polyisobutene rubber was modified by grafting succinic anhydride onto its end groups and has been used as a toughening agent for an unsaturated polyester resin. Both the functionalization and the successive reaction between the modified rubber and the polyester was investigated by Fourier transform infrared spectroscopy (FTIR). The yield behavior of the cured resins was studied by compression measurements, while the fracture properties were determined at low and high strain rate. A morphological analysis of the investigated blends has been carried out by scanning electron microscopy (SEM). A considerable enhancement of tougheness has been achieved when the modified rubber was used in place of the plain polyisobutene. The effect was found to depend on the grafting degree of the rubber and on the time period during which the two‐component mixture was allowed to react prior to the curing process. © 1995 John Wiley & Sons, Inc.
Estimation by mechanical analysis of the molecular parameters of SBR vulcanizates at different cure conditions
Authors: Marzocca Angel José 
Published: April 2003

AbstractThe changes in the network structure of SBR‐1712 during vulcanization were analyzed by means of a study of the stress–strain behavior at uniaxial extension at room temperature. In order to obtain different degrees of crosslinking, samples were cured at 414 K and 433 K at several times and were characterized by a rheometer. The conformational tube model was applied for the treatment of the stress–strain measurements of vulcanized samples. This theory allows the separation of crosslink and constraint contributions to the stress–strain behavior and relevant network parameters can be estimated. In this article the change with the temperature and time of cure of the average molecular mass of the mobile network chains, the crosslink density, the microscopic lateral tube dimension, and the root‐mean‐square end‐to‐end distance of the network chain are evaluated. © 1995 John Wiley & Sons, Inc.
Gas permeability of crosslinked HTPB–H12MDI‐based polyurethane membrane
Authors: Huang Shih‐Liang , Lai Juin‐Yih 
Published: April 2003

AbstractCrosslinked membranes were prepared by the addition of a crosslinking agent of benzoyl peroxide (BPO) to the hydroxyl‐terminated polybutadiene (HTPB) and 4,4′‐dicyclohexylmethane diisocyanate (H12MDI)‐based polyurethane (PU) solutions. The stress–strain properties of segmented HTP‐B based PUs were changed by the crosslinking between soft–soft segments. The gas permeabilities of HTPB‐based PU membranes with a suitable amount of crosslinking agent were higher than those of uncrosslinked membranes, which is due to the stretched and extended soft‐segment molecular chains. The reproducibility of gas permeability was improved by the crosslinked membranes. Thermal stability conducted by TGA was increased with increasing crosslinking agent content. FTIR was utilized to identify the segregation between hard and soft segments and structure change, which affects the gas‐transport properties. The change of glass transition temperature was detected by DSC, which can be used to manifest the degree of crosslinking of these membranes. The results of TGA, FTIR, and DSC measurements explain the crosslinking degree with different BPO content and, hence, the gas permeabilities as well. © 1995 John Wiley & Sons, Inc.
Mixed initiator approach to the surfactant‐free semicontinuous emulsion polymerization of large MMA/BA particles
Authors: O'Callaghan K. J. , Paine A. J. , Rudin A. 
Published: April 2003

AbstractThe emulsion polymerization of large monodisperse MMA/BA copolymer particles by surfactant‐free means at high solids content is described. A series of sequential seeded growth reactions were used to obtain monodisperse particles with diameters of at least 3 microns. A combination of an oil‐soluble initiator, AIBN, and a water‐soluble initiator, ammonium persulfate (AP), was used. The AIBN initiated the bulk of the polymerization and the AP provided the stabilization for the polymer particles through its charged endgroups. The amount of AP initiator to be used in each growth step was calculated empirically using a criterion of a constant ratio of moles of sulfate groups to the polymer particle surface area. © 1995 John Wiley & Sons, Inc.
Modeling high‐viscosity, melt‐phase, condensation polymer reactors with a time‐scales analysis
Authors: Sampson Kendree J. , Neogi Swati 
Published: April 2003

AbstractMathematical models for simultaneous reaction and mass transfer occurring in the manufacture of high‐viscosity, condensation polymers are considered. The specific example of polycondensation of polyethylene terephthalate is examined. Reactor performance is estimated by using a kinetic expression modified by an effectiveness factor. The effectiveness factor is correlated against a ratio of two characteristic times, one identified as the time scale of mixing and the other identified as the time scale of reaction. The time scale of mixing is estimated from experimental mixing data, thereby avoiding the use of potentially inaccurate mixing assumptions. In place of reaction experiments, overall reaction rates are generated using a more detailed mixing‐cell model. The effectiveness factor correlation is compared against previous models. Because the correlation is based on predicted reaction rates rather than experimentally measured reaction rates, the value of the present work lies in the demonstration of the time scales modeling technique. © 1995 John Wiley & Sons, Inc.
Structural characteristics of biodegradable thermoplastic starch/poly(ethylene–vinyl alcohol) blends
Authors: Simmons Stephanie , Thomas Edwin L. 
Published: April 2003

AbstractTo establish relationships among the blend composition, processing history, and the resultant properties of starch‐based thermoplastics, three varieties of corn starch: (1) Waxy Maize, (2) Native Corn, and (3) high‐amylose Hylon VII were extrusion‐blended with poly(ethylene‐vinyl alcohol) (EVOH) containing 56 mol % VOH. Wide‐angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to examine the structural characteristics of the blends. All starches were destructurized upon compounding and a fine dispersion was achieved with EVOH. The Native Corn and Hylon VII blends were phase‐separated and exhibited some miscibility between the polymer components as evident in EVOH melting‐point depression, smaller domain sizes, lower contrast between phases in TEM, and increased resistance to moisture and enzyme‐etching treatments. Starches containing amylose exhibited complexation and crystallinity in the starch fraction, although most of the crystallinity in the blends was due to the EVOH component. Waxy Maize blends were well phase‐separated with larger domain sizes and underwent phase coarsening as a function of time in the melt. When subjecting the blends to capillary flow, orientation of both starch‐rich and EVOH‐rich domains was observed at various compositions, with the EVOH component undergoing significantly more orientation relative to starch as evident by the presence of EVOH‐rich fibrils. Finally, EVOH was found to coat the surfaces of filaments produced from the blends even at rather high levels of starch (70%), which is expected to improve moisture sensitivity and slow down the initial rate of biodegradation. © 1995 John Wiley & Sons, Inc.
Viscoelastic and shrinkage behavior of ultrathin polymeric films
Authors: Weick Brian L. , Bhushan Bharat 
Published: April 2003

AbstractViscoelastic and shrinkage characteristics of five ultrathin polymeric films are presented. These films include poly(ethylene terephthalate) or PET, poly(ethylene naphthalate) or PEN, an aromatic polyamide (ARAMID), a polyimide (PI), and poly(benzoxazole) or PBO. PET film is currently the standard substrate used for magnetic tapes, and the other four films represent alternative substrates with improved material properties. Thicknesses of the films range from 14.4 μm for PET to 4.4 μm for ARAMID. A creep apparatus is used to measure the viscoelastic and shrinkage characteristics of the films. The largest amount of creep compliance was measured for PET followed by PI, PEN, ARAMID, and PBO. Creep velocity was highest for PET and PI, followed by ARAMID, PEN, and PI. Shrinkage measurements at 50°C for 100 h show that PEN shrinks more than all the other substrates. Time–temperature superposition is used to predict long‐term creep behavior, and relationships between polymeric structure and viscoelastic behavior are also discussed. Based on their relative cost and creep behavior, PEN and ARAMID substrates appear to be suitable alternatives to PET. © 1995 John Wiley & Sons, Inc.
Reactive processing of LLDPES in corotating intermeshing twin‐screw extruder. II. Effect of peroxide treatment on processability
Authors: Lachtermacher Marly G. , Rudin Alfred 
Published: April 2003

AbstractCommercial ethylene–octene linear low‐density polyethylenes (LLDPEs) were reactively extruded with low levels of a peroxide [2,5‐dimethyl‐2,5‐di(t‐butylperoxy)hexane] to modify polymer molecular structure and processing properties. Peroxide levels were kept low to avoid crosslinking. This article reports the effects of this reactive extrusion on viscoelastic properties. Rheological properties are more sensitive than are molecular structure characteristics to the changes produced by reactions of very low peroxide concentrations. Complex viscosity increases are seen, especially at low frequencies. Shear‐thining behavior is also accentuated. The crossover between G′ and G″ moves to lower frequencies. A modified Cole–Cole presentation of these data shows that the elastic component is more predominant for extrusion‐reacted materials. Peroxide‐modified materials all have higher Bagley end correction values than those of barefoot resins. The former exhibit lower power indices (more shear thinning). All these properties indicate more long‐chain branching and higher melt elasticity. However, die swell decreased as a function of peroxide concentration. Peroxide treatment results in an enhancement of elongational viscosity, both under isothermal and cooling conditions, along with a decrease in drawdown ability. The rheological changes parallel those reported earlier in molecular characteristics but are more sensitive and suitable to evaluate the effects of reactive processing. The effectiveness of the reactive extrusion process for improving processability of LLDPEs depends critically on the extrusion conditions. © 1995 John Wiley & Sons, Inc.
The dry spinning of dibutyrylchitin fibers
Authors: Szosland L. , East G. C. 
Published: April 2003

AbstractDibutyrylchitin was prepared by treatment of krill chitin with butyric anhydride in the presence of perchloric acid as a catalyst of reaction carried out at 25 to 30°C. Dibutyrylchitin is easily soluble in several organic solvents, such as acetone, alcohols, methylene chloride, and dimethylformamide. Samples of polymers with molecular weights high enough to form fibers were obtained, and dibutyrylchitin fibers were made by a simple method of dry spinning its 20 to 22% solutions in acetone. Select properties of dibutyrylchitin fibers were investigated. It was found that dibutyrylchitin fibers had tensile properties similar to or better than those of chitin and some chitin derivatives described in the literature. An attempt to convert dibutyrylchitin fibers to chitin fibers was made. It was found that chitin fibers with good tensile properties could be obtained by alkaline hydrolysis of dibutyrylchitin fibers without destroying the fiber structure. © 1995 John Wiley & Sons, Inc.
Distribution of GAP‐43 nerve fibers in the skin of the adult human hand
Authors: Verzé Laura , Carla Viglietti‐Panzica , Maurizo Stella , Monica Sica , Giancarlo Panzica 
Published: April 2003

AbstractSkin is an important region of somatic sensory input, and is one of the most innervated areas of the human body. In this study, we investigated in human hand skin the distribution of nervous structures immunoreactive for the growth‐associated protein 43 (GAP‐43) and the protein gene product 9.5 (PGP 9.5). GAP‐43 is a neuronal presynaptic membrane protein that is generally considered to be a marker of neuronal plasticity. PGP 9.5 is a neuron‐specific soluble protein that is widely used as general marker for the peripheral nervous system. The entire neural network of the dermis and epidermis was stained with antibody to PGP 9.5. In the dermis, there were fewer GAP‐43‐immunostained nerve fibers than PGP 9.5‐immunostained nerve fibers, whereas in the epidermis the numbers were equal. Only some Merkel cells and Meissner corpuscles were GAP‐43‐immunoreactive. In conclusion, our results show that GAP‐43 protein is expressed in a subset of PGP 9.5‐immunoreactive nerve structures. Anat Rec Part A 272A:467–473, 2003. © 2003 Wiley‐Liss, Inc.
Evaluating an α–β filter in terms of increasing a track update‐sampling rate and improving measurement accuracy
Authors: Kosuge Yoshio , Ito Masayoshi 
Published: April 2003

AbstractThe α–β filter estimates the true values of the position and velocity of the target from the observed target position. If the driving noise indicating the ambiguity of the target motion differs, then various different α–β filters can be derived from a Kalman filter that uses a constant‐velocity linear motion model. On the other hand, the MV filter is an α–β filter that minimizes the variations of the steady error of the predicted value of the target position for a target in constant‐velocity linear motion, under the condition that the steady tracking error for the target with constant acceleration is constant. This MV filter cannot be derived from the Kalman filter. Note that there are methods of increasing the sampling rate and of improving observation accuracy for improvement of tracking capability. However, when multiple targets are tracked at the same time, the electromagnetic illumination time per target is necessarily reduced. In this paper, the tracking capability of the above α–β filter with constant gains is evaluated in terms of the tracking accuracy for a target in constant‐velocity linear motion under the condition that the steady tracking error for a target in constant‐acceleration motion is constant. It is found advantageous to increase the sample rate rather than to improve the observation accuracy if the electromagnetic illumination time is constant. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 10–20, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10113
Fundamental study of a λ/4 microwave‐band wave absorber using conductive paper
Authors: Otsuka Kenjiro , Hashimoto Osamu , Orita Mitsuru , Morita Yukinobu 
Published: April 2003

AbstractThis paper discusses a λ/4‐type wave absorber for the microwave band made with conductive paper, which is paper with a coating of conductive material. A simplified wave absorber of this type is first designed and constructed for the X band and Ku band. Using the resulting absorption characteristics, experimental formulas are derived for the relative permittivity and surface resistance. These formulas are then used to design and construct a more practical wave absorber, whose absorption characteristics are measured. Excellent absorption characteristics, better than 20 dB, are verified in the intervals from 8.2 to 10.6 GHz and from 14.1 to 17.2 GHz for wave absorption in the X band and Ku band, respectively, although there is a difference of approximately 0.4 dB between the designed matching frequency and the measured value. Design guidelines for such a microwave absorber using a conductive coating are then presented. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 100–107, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1180
State feedback control of timed hybrid Petri nets
Authors: Tanaka Atsushi , Ushio Toshimitsu , Kodama Shinzo 
Published: April 2003

AbstractA system in which discrete variables and continuous variables are mixed is called a hybrid system. Many models have been proposed for description of hybrid systems. A mode graphically describing the causality relationship between the variables is the hybrid Petri net (HPN). A mode in which the concept of time is introduced into the HPN is the timed HPN (THPN). In this paper, with regard to the THPN with an external input place (THPNIP), state feedback control is discussed in the case where the control specifications are given by a description on the attainable ensemble. In THPNIP, in general there is no guarantee that the maximum allowable feedback, which is the maximum element in the ensemble of the state feedback satisfying the control specification, will exist. Hence, the necessary and sufficient conditions are presented for the existence of the maximum allowable feedback. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 1–7, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10011
Proposal of eye‐gaze character input interface with guide area
Authors: Ban Hisayuki , Sugamata Ikuma , Itakura Naoaki , Sakamoto Kazuyosi , Kitamoto Taku 
Published: April 2003

AbstractIt has been difficult in the past to differentiate simply an input eye‐gaze (fixation) and a noninput eye‐gaze (pause) in using an eye‐gaze character input interface. This is because there are two major gazes having two different roles, “inputting” and “searching,” which are difficult to differentiate from gazing time, etc. In this study, a new screen design interface has been proposed. In this design, input areas for inputting an “input” are assigned on the left and right side of the screen, and a guide area having a character arrangement similar to the input areas is assigned for “searching” in the center. Since the location of a character can be searched by the guide area, the eye‐gaze for “searching” can be expected to occur in the guide area and the eye‐gaze for “inputting” in the input areas. Whether noninput eye‐gazes (pauses) in the input areas are reduced by the guide method is tested by comparing the past and the guide methods. As a result, the efficacy of the guide method has been verified from the fact that the frequency of noninput eye‐gazes (pauses) is decreased about 40% from that of the past method, while the overall eye‐gaze frequency increases with the guide method, with its increased inputting time as compared with the past method. In addition, it has been found that input eye‐gazes and noninput eye‐gazes (pauses) which could not be separated based on time up to now could be separated at a rate of 88%. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 36–42, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10117