bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shape‐Memory Materials, Modeling
Authors: Bernardini Davide , Pence Thomas J. 
Published: November 2003

AbstractAn understanding of shape‐memory behavior requires knowledge of various physical processes that operate on different length scales. The crystallographic shifts that are responsible for shape‐memory behavior take place in unit cells of atomic dimension. Here, however, these microscopic length scales are not the focus, rather, this article considers the macroscopic scale modeling that is useful for the engineering assessment of thermomechanical response (stress–strain–temperature) and energy balances (including damping) for devices such as connectors, actuators, vibration absorbers, and biomedical stents. The macro scale is involves primary design evaluation such as predicting triggering forces and determining range of motion. Since the shape‐memory material is incorporated into a larger engineered device or structure, there is also required detailed computational simulation of the system as a whole.
Vibration Control
Authors: Choi Seung‐Bok 
Published: November 2003

AbstractThe insatiable demand ford high performance on various dynamic systems quantified by high‐speed operation, high control accuracy, and lower energy consumption has triggered vigorous research on vibrational control of distributed flexible structures and discrete systems. Numerous control strategies for conventional electromagnetic actuators have been proposed and implemented to suppress unwanted vibration. However, the successful empirical realization of electromagnetic actuators may be sometimes very difficult under certain conditions due to hardware limitations such as saturation and response speed. This difficulty can be resolved by employing smart material actuators in vibrational control. As is well‐known, smart material technology features actuating capability, control capability, and computational capability. Therefore, these inherent capabilities of smart materials can execute specific functions autonomously in response to changing environmental stimuli. Among many smart material candidates, electrorheological(ER) fluids, piezoelectric materials, and shape‐memory alloys are effectively exploited for vibrational control in various engineering applications. A viable vibrational control algorithm can be optimally synthesized by integrating control strategies, and actuating technology, and sensing technology. The design philosophy presented contains a very large number of decisions and design parameters for the characteristics of controllers, actuators, and sensors. In this article, two different flexible smart structures fabricated from ER fluids and piezoelectric materials are introduced, and vibrational control techniques for each smart structure are presented. In addition, vibrational control methodology for a passenger vehicle under various road conditions is given by adopting an ER damper, followed by vibrational control of a flexible robotic manipulator that features piezoceramic actuators.
Caves and Other Low‐Light Environments: Aerophitic Photoautotrophic Microorganisms
Authors: Hoffmann Lucien 
Published: November 2003

AbstractHistorical DevelopmentThe Low‐Light EnvironmentLow‐Light Microbial PhotoautotrophsSome Troglophilic and Troglobitic Photosynthetic MicroorganismsDistribution of Photoautotrophs in CavesPhysiological EcologyEconomic Importance: “Green Sickness” of Caves
Salinity Effects on the Physiology of Soil Microorganisms
Authors: Rudulier Daniel Le , Mandon Karine , Dupont Laurence , Trinchant Jean Charles 
Published: November 2003

AbstractSoil Microbiology and Stress ConditionsCompatible Solutes and OsmoprotectantsSalinity Tolerance in Gram‐Positive Soil BacteriaOsmoprotection in Gram‐Negative Rhizosphere BacteriaPhysiological Effects of Salinity on Rhizobium‐Legume Symbiosis
Impact behavior of unidirectional polyethylene–glass fibers: Resol/vinyl acetate‐2‐ethylhexylacrylate interpenetrating polymer network systems
Authors: Datta Chandan , Basu Diya , Banerjee Amaranth 
Published: November 2003

AbstractResol was solution blended with vinyl acetate‐2‐ethylhexylacrylate (VAc–EHA) resin in an aqueous medium at a 90‐10 w/w ratio with hexamethoxymethylmelamine (HMMM) as crosslinker. Here we aimed to study the impact behavior of unidirectional laminates cast from (Resol/VAc–EHA/HMMM)/glass fiber (GF), (Resol/VAc–EHA/HMMM)/polyethylene fiber (PEF), and (Resol/VAc–EHA/HMMM)/GF/PEF (hybrid) and to study the role of PEF ply/plies in hybrid laminates toward the impact behavior, as dependent on the relative position of the ply/plies. A brittle failure mode was observed in the GF‐reinforced laminates, which tended to the ductile failure mode, with the incorporation of PEF ply/plies. Again, the impact fracture mode of GF was minimized by the placement of PEF ply/plies at the impacted side of the hybrid laminates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 339–342, 2004
Dialysis membranes from polyethylene films grafted with acrylic acid
Authors: El‐Awady Nagwa I. 
Published: November 2003

AbstractLow‐density polyethylene‐g‐poly(acrylic acid) membranes were prepared by the direct radiation grafting of aqueous acrylic acid solutions (containing Mohr's salt) onto low‐density polyethylene films and were irradiated at two different irradiation doses (2 and 3 Mrad) at a dose rate of 0.02 Mrad/h. Two series of polyethylene‐g‐poly(acrylic acid) membranes with 100 and 150% grafting were obtained. The free carboxylic acid groups in the grafted films were converted into the corresponding acrylates by reactions with different metal salts. The swelling (water uptake) and dialysis permeability of glucose and urea through the grafted membranes in different metal‐ion forms were investigated. The prepared membranes showed good permeability to both solutes, which increased as the hydrophilicity of the membrane increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 10–14, 2004
Copolyester of trimellitic acid, glycerol, and poly(ethylene glycol): Synthesis and characterization
Authors: Pramanick D. , Pramanick R. , Betal G. 
Published: November 2003

AbstractA series of copolyesters having a broad range of biodegradable crosslinks were synthesised by FeCl3‐catalyzed polyesterification of trimellitic acid and glycerol containing a small mol percent of poly(ethylene glycol) (PEG) of varied molecular weights. The polymer samples designated as I (1.5% PEG 2000), II (4.5% PEG 2000), III (7.5% PEG 2000), IV (1.5% PEG 4000), V (4.5% PEG 4000), VI (7.5% PEG 4000), VII (1.5% PEG 6000), VIII (4.5% PEG 6000), and IX (without PEG) are insoluble and moderately tough‐to‐elastic solids and were characterized by their swelling values in ethanol, glass transition temperatures (Tg), IR spectra, and X‐ray diffractograms. Sample IX (0% PEG) has the lowest equilibrium swelling (12% at 25°C) and the highest Tg (155°C) and, therefore, the highest crosslink density. The swelling increases and the Tg decreases as the PEG content or PEG molecular weight in a glycerol–PEG combination increases, indicating a corresponding decrease in the crosslink density of the polymers. Further, the equilibrium swelling value increases with increasing temperature. The IR spectra of the polymers indicate the formation of ester bonds at the expense of COOH and OH groups. The X‐ray diffractograms show their semicrystalline nature. The percent crystallinity values of 53, 52, 49, and 46 for II, III, V, and VII, respectively, and 54 for IX showed that the percent crystallinity decreases with an increasing PEG content and molecular weight in the same way as do the Tg values. Thus, higher Tg values are associated with a higher percent crystallinity, that is, with structures of higher order. The synthesized polymer samples with varied crosslink (biodegradable) densities are expected to be very suitable as matrices for controlled drug delivery over a varied period of time. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 343–346, 2004
Crosslinking and decomposition reactions of epoxide‐functionalized polynorbornene. II. Impact of reactions on mechanical properties
Authors: Chiniwalla Punit , Bai Yiqun , Elce Ed , Shick Rob , Ann Bidstrup Allen Sue , Kohl Paul 
Published: November 2003

AbstractLow dielectric constant materials are critical to meeting the demand for continual reduction in feature sizes and increase in interconnect density required for future high‐speed microelectronic devices. Polymers based on functionalized norbornenes are inherently attractive for these applications as they exhibit good electrical properties such as a low dielectric constant and appealing mechanical properties. Although polynorbornenes inherently possess properties that are attractive for microelectronics packaging, films of these polymers are not solvent‐resistant. Solvent‐resistant crosslinked films can be attained by generation of acid species to promote cationic crosslinking of epoxide side groups. This article is the second part of a two‐part study investigating the crosslinking of a copolymer of decyl norbornene and epoxide norbornene. In the first part of this study, it was proposed that epoxide decomposition reactions are also possible at cure temperatures greater than 160°C. This decomposition mechanism results in the complete loss of crosslinkable epoxide groups while leaving the norbornene backbone intact. Although crosslinking and decomposition reactions have independent mechanisms, both reactions directly affect the level of crosslinking. In this part of the study, the solvent swelling behavior, tensile modulus, elongation to break, and residual stress were investigated for polymer films cured under various conditions to validate the proposed mechanisms. The trends observed with these properties are consistent with the counteracting nature of epoxide crosslinking and decomposition reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1020–1029, 2004
Wall effects on flow of polymer/particulate/(carboxylic acid) in dies and rheometers
Authors: Ahn Sungtae , White James L. 
Published: November 2003

AbstractThe addition of carboxylic acids to polyolefins results in an apparent slippage flow along rheometer and die walls. In this article, we seek to extend this investigation to polymer/particulate compounds. An experimental study on the influence of carboxylic acid additive in polyethylene/filler and polystyrene/filler compounds in rheometers is described. Capillary and cone‐plate experiments are reported. A series of particle fillers of varying character, including carbon black, calcium carbonate, zinc oxide, and talc are compared. The aliphatic fatty acid, octadecanoic acid, was used as an additive. Significant viscosity reductions were observed. The greatest effects were found in polyethylene/(carbon black) and polystyrene/(calcium carbonate) compounds. All of the polyethylene compounds exhibited slip flow, but the polystyrene compounds did not. Apparently much of the octadecanoic acid was interacting with the polar particle fillers and not with the die wall. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 651–658, 2004
Intraligand cooperation in metal‐ion binding by immobilized ligands: The effect of bifunctionality
Authors: Alexandratos Spiro D. , Smith Stephanie D. 
Published: November 2003

AbstractIntraligand cooperation between carbonyl and phosphoryl moieties in ion bonding was studied by the synthesis of β‐ketophosphonic acid (βkPh), phosphonoacetic acid (PhAc), and phosphonic acid (Ph) resins. A subsequent reaction gave bifunctional analogues with sulfonic acid as an additional ligand (βkPhs, PhAcs, and Phs resins). Ionic affinities were quantified with dilute solutions of Cu(II), Cd(II), and Pb(II) in 0.10M HNO3. The effect of an increased solution ionic strength was studied with a second set of 0.10M HNO3/0.04M NaNO3 solutions. The results from the monofunctional resins and nitric acid alone showed that βkPh had the highest metal‐ion affinities, whereas PhAc had affinities similar to those of Ph. Comparing βkPh to Ph led to the conclusion that the carbonyl group was a strong contributor to binding through intraligand cooperation with the phosphoryl group, whereas comparing PhAc to Ph led to the conclusion that the carbonyl group played no role in the ion binding. These opposing conclusions were reconciled as follows: (1) the extent of complexation from the 0.10M HNO3 solutions increased significantly when the monofunctional resins were sulfonated and (2) a comparison of the results for the monofunctional resins when contacting Cu(II), Cd(II), and Pb(II) in the absence of NaNO3 with those for the bifunctional resins when contacting those ions in the presence of NaNO3 showed that the ionic affinities were comparable for Ph and Phs, greater for PhAcs than for PhAc, and comparable for βkPhs and βkPh. The resins PhAcs and βkPh displayed comparable ionic affinities that were higher than that of Ph. The results were consistent with the conclusion that, in the monofunctional resin, the affinity of the phosphonoacetate ligand for the metal ions was reduced because of intraligand hydrogen bonding. Intraligand cooperation was, therefore, an important variable in enhancing the metal‐ion affinities, but its effect could be attenuated by intraligand hydrogen bonding. This attenuation could be eliminated by the introduction of a highly hydrophilic group into the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 463–468, 2004
Gradient of birefringence: A new direction for gradient optics
Authors: Nadareishvili L. , Gvatua S. , Blagidze I. , Zaikov G. 
Published: November 2003

AbstractThe fabrication of a new type of polymeric optical element with specified properties with a given axial gradient of birefringence (GB) is described. The estimation of some technological spaces of GB element fabrication is given. For the fabrication of GB elements, an inhomogeneous mechanical field with a given heterogeneity was used. GB elements on poly(vinyl spirit) and polyethyleneterephthalate thin films bases were created, and their properties were investigated. The maximal value of the implemented birefringence was 1.4 × 10−2. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 489–493, 2004
Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl acetate)
Authors: Hsu Wen‐Ping 
Published: November 2003

AbstractThe results of the miscibility between the chemically similar polymers poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) published so far show inconsistent statements concerning miscibility. The problems may be due to differences in molecular weights, tacticity, and preparation methods of the polymers. This investigation was carried out by using either chloroform or tetrahydrofuran (THF) as solvent to prepare the blends, because to our knowledge, nobody has reported any tacticity effect of PMMA on the miscibility with PVAc. Therefore, in this article, different tactic PMMAs were used to mix with PVAc and their miscibility was studied calorimetrically. The results showed little effect of solvent and tacticity. PMMA and PVAc were determined to be almost completely immiscible because of the observation of two Tg's. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 35–39, 2004
Preparation and structural characterization of nanocrystalline poly(vinyl chloride)
Authors: Xiong Chuanxi , Wang Tao , Liu Qihong , Dong Lijie , Chen Juan , Liu Dan 
Published: November 2003

AbstractThis article describes the development of novel nanocrystalline poly(vinyl chloride) (PVC) for potential applications in PVC processes and reports improvements in the mechanical properties and thermal resistance. Before the preparation of nanocrystalline PVC via jet milling, PVC was spray‐treated and heat‐treated to improve its crystallinity. The pulverization and degradation, morphology, crystalline structure, and melting‐point changes of postmodified PVC during jet milling and the relationship between the distributions of the particle size and processing temperature were investigated. X‐ray analysis and density testing indicated increased density and improved crystallinity. The crystalline region of nanocrystalline PVC was less than 80 nm, with a particle size distribution of 5–20 μm and a melting point of less than 128°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 563–569, 2004
Synthesis and characterization of poly(ethylene terephthalate) nanocomposites with organoclay
Authors: Ou Cheng Fang , Ho Mong Ting , Lin Jia Rung 
Published: November 2003

AbstractPoly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites were prepared by solution intercalation method. The clay was organo‐modified with the intercalation agent cetylpyridinium chloride (CPC). Wide‐angle X‐ray diffraction (XRD) showed that the layers of MMT were intercalated by CPC. Four nanocomposites with organoclay contents of 1, 5, 10, and 15 wt % were prepared by solution blending. XRD showed that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay present. According to the results of differential scanning calorimetry (DSC) analysis, clay behaves as a nucleating agent and enhances the crystallization rate of PET. The maximum enhancement of crystallization rate for the nanocomposites was observed in those containing about 10 wt % organoclay within the studied range of 1–15 wt %. From thermogravimetric analysis (TGA), we found that the thermal stability of the nanocomposites was enhanced by the addition of 1–15 wt % organoclay. These nanocomposites showed high levels of dispersion without agglomeration of particles at low organoclay content (5 wt %). An agglomerated structure did form in the PET matrix at 15 wt % organoclay. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 140–145, 2004
Graft‐modified HCPE with methyl methacrylate by the mechanochemistry reaction. II. Physical‐mechanical properties and processability
Authors: Zhao Ji‐Ruo , Feng Ying , Chen Xin‐Fang 
Published: November 2003

AbstractIn this article, the physical‐mechanical properties and processability of graft‐modified highly chlorinated polyethylene (HCPE; chlorine contents: ≥ 60%) with methyl methacrylate (MMA) by mechanochemistry reaction were studied. The results showed that the HCPE‐g‐MMA system is superior to unmodified HCPE in physical‐mechanical properties, particularly in processability. In addition, the HCPE‐g‐MMA system, with about 62% chlorine content, was the same as PVC in its physical‐mechanical properties. The HCPE‐g‐MMA system, with about 65.5% chlorine content, is the same as chlorinated poly(vinyl chloride) (CPVC) in its physical‐mechanical properties, except that the Vicat softening temperature and processability of HCPE‐g‐MMA system are superior to PVC and CPVC. Compared with PVC and CPVC, the HCPE‐g‐MMA system proves better due to its lack of a toxic monomer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 282–287, 2004
Critical processing temperature in the manufacture of fine‐celled plastic/wood‐fiber composite foams
Authors: Guo G. , Rizvi G. M. , Park C. B. , Lin W. S. 
Published: November 2003

AbstractThe main benefits of incorporating wood fibers (WF) in plastics are the increased stiffness and lowered cost of the resulting composites. However, these improvements are usually accompanied by a reduction in the ductility and impact resistance. These shortcomings can be removed by effectively foaming and incorporating a fine‐celled structure in these composites. The volatiles released from WF during processing are known to deteriorate the cell structure. The maximum processing temperature, which affects the amount of volatiles released by the WF during extrusion of fine‐celled plastic/WF composite, affects the cell morphology. This study was undertaken to identify the critical temperature above which the cellular structure of WF composite foams is significantly deteriorated. To clearly identify the effects of the volatiles generated from WF on the cellular morphology, neither a chemical blowing agent nor a physical blowing agent was used in the foam processing. The experimental results show that regardless of the drying method, the highest processing temperature of plastic/WF composites should be minimized, preferably below 170°C, to avoid the adverse effects of the volatiles generated from the WF during processing. A method of estimating the emissions from WF during extrusion processing by using the TGA data is also proposed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 621–629, 2004
Development of an environmentally friendly solventless process for electronic prepregs
Authors: Permadi  , Castro Jose M. 
Published: November 2003

AbstractThe most common commercial processes for manufacturing prepregs for electronic applications use solvent‐based resin systems. Solvents are not environmentally friendly and contribute to voids in prepregs and laminates. The resin impregnation process is performed in an open resin bath. This low‐pressure impregnation is conducive to voids in prepregs. Voids cause product variability, which is a major source of scrap in board shops. To eliminate these drawbacks, a solventless process, based on the concept of injection pultrusion, has been developed. The impregnation is performed in a die under pressure to minimize voids. In previous work, chemorheological and kinetic measurements were used to identify a potential epoxy‐based resin system. In addition, flow visualization with model fluids was used to establish the basic flow mechanism. Here we use the previous results to develop a mathematical model for the B‐staging process. A prototype B‐staging die has been built and used to verify the mathematical model. The results show that the model agrees well with the experimental data for low pulling speeds and slightly underpredicts the runs at high pulling speeds. The properties of the prepregs, the dielectric constant (DK) and dielectric loss (DF), have also been measured in this research. The measurements show that the solventless prepregs have acceptable DK and DF values according to the Institute for Printed Circuits FR‐4 designation (a permittivity and tangent loss standard). A microscope has been used to observe the void contents of the prepregs. The solventless prepregs have been compared against standard FR‐4 prepregs and shown qualitatively to have fewer voids. Based on the mathematical model, two potential process alternatives for the manufacture of solventless prepregs have been developed and analyzed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1136–1146, 2004
Thermal behavior of pentachlorophenyl methacrylate–acrylonitrile copolymers
Authors: Azab M. M. 
Published: November 2003

AbstractAcrylonitrile was copolymerized with pentachlorophenyl methacrylate (PCPMA)in dimethyl formamide using azobisisobutyronitrile as initiator. The composition of the copolymers was determined by nitrogen analysis and the monomer reactivity ratios (r1 and r2) were calculated. Both the homopolymer and the copolymers were characterized by a variety of spectral and thermal methods. Thermogravimetry and differential thermal analysis data showed that the comonomer (PCPMA) initiates the nitrile oligomerization reaction in the copolymer upon heating. A mechanism for the initiation of (PCPMA) units in the nitrile copolymers was also proposed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 296–302, 2004