bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of wood plastic composite panels made from waste fiberboard and particleboard
Authors: Chaharmahali Majid , Tajvidi Mehdi , Najafi Saeed Kazemi 
Published: March 2008

AbstractThe possibility of producing wood‐plastic panels using a melt blend/hot press method was studied in this research. The studied panels were compared with conventional medium density fiberboard (MDF) and particleboard (PB) panels. Wood‐plastic panels were made from high density polyethylene (as resin) and MDF waste and PB waste (as natural fiber) at 60, 70, and 80% by weight fiber loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistances, and impact strength were studied. Results indicated that the mechanical properties of the composites were strongly affected by the proportion of the wood flour and polymer. Maximum values of flexural modulus of wood plastic panels were reached at 70% fiber content. Flexural strength, screw and nail withdrawal resistance, and impact strength of wood plastic composites declined with the increase in fiber content from 60 to 80%. This was attributed to the lack of compatibility between the phases. The produced panels outperformed conventional PB panels regarding their mechanical properties, which were acceptable when compared with MDF panels as well. The best feature in the produced panels was their screw withdrawal resistance, which is extremely important for screw joints in cabinet making. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Synthesis and characterizations of poly(α‐naphthylamine)—Nanocomposites
Authors: Anbarasan R. , Anandhakrishnan R. , Vivek G. 
Published: March 2008

AbstractPoly(α‐naphthylamine) (PNA)—natural clay nanocomposites were prepared by in situ polymerization method through oxidative initiation method. Effect of nanoclay on the rate of polymerization (Rp) of Naphthylamine (NA), thermal stability of PNA, and conductivity of PNA were tested. Effect of nanoclay on the morphology of PNA was also tested. The TGA results inferred that the % weight residue remain above 700°C was increased with the increase of amount of clay. XRD results confirmed the intercalation of PNA into the basal spacing of natural clay. TEM showed the presence of nanosized particle in the PNA‐natural clay nanocomposites. The conductivity value of polymer‐nanocomposite has increased with the increase of amount of natural clay. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of fiber‐mat anisotropy on 1D mold filling in LCM: A numerical investigation
Authors: Tan Hua , Pillai Krishna M. 
Published: March 2008

AbstractThe 1D flow experiment is one of the most common methods to measure the saturated and unsaturated permeabilities as well as to study the unsaturated flow in liquid composite molding (LCM) processes used for manufacturing polymer composites. The effective permeability along a flow direction in an anisotropic fiber mat, which is a function of the principal components of the permeability tensor and the angle between the principal and flow directions, is based on the assumption of uniform 1D flow in the mat. In the present paper, the validity of such unidirectional flow assumption is shown to depend on three factors, i.e., the fiber‐mat aspect ratio, the anisotropy ratio (the ratio of the major and minor principal in‐plane permeabilities), and the angle of the principal permeability direction. A mold‐filling simulation for hard‐mold LCM processes based on the control volume/finite element formulation is used to investigate how these three factors affect the 1D flow. A new algorithm for applying the uniform inlet‐pressure condition prevalent in the 1D flow mold under the constant‐flow‐rate injection is developed to match the actual conditions in the mold. Our numerical results show that the three aforementioned factors have significant influence on the inlet‐pressure history as well as on the mold‐filling pattern. Maximum deviations from the unidirectional flow predictions in the inlet‐pressure history as well as the flow‐front progress is seen when the principal permeability direction is at an angle of 45° with respect to the flow direction; these deviations worsen with a decrease in the mat aspect ratio and with an increase in the anisotropy ratio. However, the inlet‐pressure history remains linear and the progress of the average flow‐front remains predictable by the 1D flow theory. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
The effect of gamma and electron beam irradiation on the thermal and mechanical properties of injection‐moulded high crystallinity poly(propylene)
Authors: Hassan Medhat M. , El‐kelesh Nabil A. , Dessouki Ahmed M. 
Published: March 2008

AbstractIn the present study, the effect of gamma and electron beam (EB) irradiation on the thermal and mechanical properties of high crystalline polypropylene (HPP) was studied. To study the structural modifications of HPP polymer which could occur following these treatments at different doses (20, 40, 60, 80, 100, and 120 kGy) were applied to all samples. Nonirradiated HPP were used as control samples, differential scanning calorimetry analysis, thermogravimetric analysis, and Mechanical tests were carried out to evaluate the effect of both irradiation treatments (EB and gamma irradiation) on HPP samples. Irradiated samples of HPP decreases melting temperature (Tm) of matrix in EB more than in gamma rays up to 5°C. The changes of mechanical properties exhibit different radiation stability towards 60Co‐gamma radiation and EB radiation. This difference reflects much higher penetration of the gamma radiation through the polymeric material as a function of sample thickness. The degradation on polymer properties caused by gamma irradiation was more than that caused by EB irradiation. Next, we compared the effects of gamma and EB irradiation to determine which of these two processes better maintained the integrity of the irradiated product. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.
Boehmite nanorod‐reinforced‐polyethylenes and ethylene/1‐octene thermoplastic elastomer nanocomposites prepared by in situ olefin polymerization and melt compounding
Authors: Halbach Tobias S. , Thomann Yi , Mülhaupt Rolf 
Published: March 2008

AbstractNanocomposites of polyethylene (HDPE) and poly(ethylene‐co‐1‐octene) thermoplastic elastomers, both containing boehmites with variable sizes, shapes, and aspect ratios (1–20), were prepared by means of in situ olefin polymerization and melt compounding. The in situ olefin polymerization in the presence of boehmite nanorods afforded nanocomposites containing 4–8 wt % of boehmite. In an alternative process, the in situ olefin polymerization was used to produce polyolefins with high boehmite content of 50 wt % as masterbatches for polyolefin melt compounding with ethylene homo‐ and copolymers. The addition of the boehmite nanofillers improved the stiffness without sacrificing high elongation at break. The stiffness, as expressed by Young's modulus, increased with increasing boehmite aspect ratio. In case of thermoplastic elastomer nanocomposites the increase of stiffness was accompanied by a simultaneous increase of elongation at break. According to transmission electron microscopy (TEM), fine dispersion of the polar boehmite nanorods and nanoplatelets within the nonpolar hydrocarbon polymer matrix was obtained without requiring the addition of special dispersing agents or functionalized polyolefin compatibilizers. The comparison of melt compounding of polyethylene with boehmites or polyethylene/boehmite masterbatches revealed that compounding of masterbatches prepared by in situ polymerization filling afforded much finer and more uniform nanoboehmite dispersions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2755–2765, 2008
N‐vinylcaprolactam‐based microgels: Effect of the concentration and type of cross‐linker
Authors: Imaz Ainara , Forcada Jacqueline 
Published: March 2008

AbstractNew microgel particles produced by using N‐vinylcaprolactam (VCL) and poly(ethylene glycol) diacrylate (PEGDA) or N,N′‐methylenbisacrylamide (BA) were synthesized in a batch reactor. The influence of the concentration and type of crosslinker on polymerization kinetics and colloidal characteristics of such temperature‐sensitive particles was studied. The partial and total conversion evolutions of VCL, PEGDA, and BA were determined by quantitative 1H NMR and the average diameters of microgel particles together with the swelling–deswelling behavior were analyzed by means of photon correlation spectroscopy (PCS). Partial and total conversions, final average diameters at collapsed state, and the swelling–deswelling behavior varied as a function of the type of crosslinker. These results were attributed to the higher solubility and stabilizing ability of PEGDA compared with that of BA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2766–2775, 2008
Polymerization of 3‐ethynylthiophene with homogeneous and heterogeneous Rh catalysts
Authors: Svoboda Jan , Sedláček Jan , Zedník Jiří , Dvořáková Gita , Trhlíková Olga , Rédrová Dana , Balcar Hynek , Vohlídal Jiří 
Published: March 2008

Abstract3‐Ethynylthiophene (3ETh) was polymerized with Rh(I) complexes: [Rh(cod)acac], [Rh(nbd)acac], [Rh(cod)Cl]2, and [Rh(nbd)Cl]2 (cod is η2:η2‐cycloocta‐1,5‐diene and nbd η2:η2‐norborna‐2,5‐diene), used as homogeneous catalysts and with the last two complexes anchored on mesoporous polybenzimidazole (PBI) beads: [Rh(cod)Cl]2/PBI and [Rh(nbd)Cl]2/PBI used as heterogeneous catalysts. All tested catalyst systems give high‐cis poly(3ETh). In situ NMR study of homogeneous polymerizations induced with [Rh(cod)acac] and [Rh(nbd)acac] complexes has revealed: (i) a transformation of acac ligands into free acetylacetone (Hacac) occurring since the early stage of polymerization, which suggests that this reaction is part of the initiation, (ii) that the initiation is rather slow in both of these polymerization systems, and (iii) a release of cod ligand from [Rh(cod)acac] complex but no release of nbd ligand from [Rh(nbd)acac] complex during the polymerization. The stability of diene ligand binding to Rh‐atom in [Rh(diene)acac] catalysts remarkably affects only the molecular weight but not the yield of poly(3ETh). The heterogeneous catalyst systems also provide high‐cis poly(3ETh), which is of very low contamination with catalyst residues since a leaching of anchored Rh complexes is negligible. The course of heterogeneous polymerizations is somewhat affected by limitations arising from the diffusion of monomer inside catalyst beads. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2776–2787, 2008
Styrene 4‐vinylbenzocyclobutene copolymer for microelectronic applications
Authors: So Ying‐Hung , Hahn Stephen F. , Li Yongfu , Reinhard Molly T. 
Published: March 2008

AbstractStyrene and 4‐vinylbenzocyclobutene (vinyl‐BCB) random copolymers were prepared by free radical polymerization and studied for suitability as a dielectric material for microelectronic applications. The percentage of vinyl‐BCB in the copolymer was varied from 0 to 26 mol % to optimize the physical and mechanical properties of the cured copolymer as well as the cost. Copolymer in which 22 mol % of vinyl‐BCB was incorporated along with styrene produced a thermoset polymer which, after cure, did not show a Tg before decomposition at about 350 °C. The polymeric material has a very low dielectric constant, dissipation factor, and water uptake. The fracture toughness of the copolymer was improved with the addition of 20 wt % of a star‐shaped polystyrene‐block‐polybutadiene. Blends of the poly(styrene‐co‐vinyl‐BCB) with the thermoplastic elastomer provided material that maintained high Tg of the cured copolymer with only a slight decrease in thermal stability. The crosslinked styrenic polymer and toughened blends possess many properties that are desirable for high frequency‐high speed mobile communication applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2799–2806, 2008
Nonisothermal crystallization and melting behavior of syndiotactic polypropylenes of different microstructure
Authors: Vanegas Ma. Eulalia , Quijada Raúl , Serafini Daniel , Galland Griselda B. , Palza Humberto 
Published: March 2008

AbstractSyndiotactic polypropylenes and their copolymers with 1‐olefins were synthesized using two metallocene/MAO catalytic systems, and the effect of the different microstructures on nonisothermal crystallization and subsequent melting was studied. Using differential scanning calorimetry (DSC) it was observed that samples with lower content of defects showed crystallization on cooling from the melt, and a double melting peak in the subsequent heating scan, the latter associated with melt, recrystallization and remelt processes that it was confirmed by its nonreversing exothermic process found by means of temperature modulated DSC (MDSC). However, polymers with high amount of defects showed cold crystallization on heating followed by a melting process, that it was observed by MDSC. Wide angle X‐ray diffraction was used for characterizing the changes of crystalline forms in relationship with crystallization process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 798–806, 2008
Adiabatic runaway reaction, blowdown, quench, and inhibition in fire‐engulfed vessels: An experimental study
Authors: Waldram Simon , Tee Daren , Ladlow Caroline 
Published: March 2008

AbstractTwo linked PHI‐TEC adiabatic calorimeters were used to simulate a fire heating and runaway reaction scenario. This corresponded to plant‐scale continuous flow reactors that are used for the production of acrylamide: two‐phase venting from a fire‐exposed “blocked in” reactor into a dump tank containing water and a chemical inhibitor was simulated. After venting, continuous supplies of electrical power to both the reactor and the quench vessel were maintained so as to simulate sustained fire exposure. The main purpose of the study was to determine whether this venting and continued fire exposure could induce any secondary decomposition reactions. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Optical phase diagram of amorphous carbon films determined by spectroscopic ellipsometry
Authors: Budai J. , Toth Z. 
Published: March 2008

AbstractIn this study we show how amorphous carbon films can be categorized using their optical properties which change according to their structure and composition. Hydrogenated and hydrogen free diamond‐ and graphite‐like carbon films, characterized previously by several methods, were analyzed with spectroscopic ellipsometry in the 1.24‐5 eV photon energy range. To model the measuredΨandΔspectra the optical properties of the films were described with Tauc‐Lorentz oscillator model, Gaussian line shape and Cauchy's dispersion relation. The results and the films are compared in terms of the highest refractive index (nmax) and the corresponding pho‐ ton energy (Emax). When plottingEmaxas a function of the maximal refractive index the data draw out a curved track. The data of different type films are located at different parts of the curve which are placed at corresponding positions for all models. Thus the trends derived with different modeling are the same, even though the optical properties of the films derived from ellipsometric measurements may slightly depend on the applied model. Hence this representation of the refractive index of a‐C and a‐C:H films can be utilized for qualitative analysis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ and real‐time investigation of ZnO thin films growth onto rigid and flexible substrates
Authors: Koidis C. , Logothetidis S. , Georgiou D. , Laskarakis A. 
Published: March 2008

AbstractZinc Oxide (ZnO) has emerged as one of the most promising TCO materials due to its intrinsic properties. In this work, in‐situ and real‐time Vis‐fUV Spectroscopic Ellipsometry (SE) (1.5‐6.5 eV) has been employed for the monitoring of the growth of ZnO thin films. Films were firstly deposited on Si substrates in order to find the optimum deposition conditions and then to Poly‐Ethylene Terephthalate and Poly‐Ethylene Naphthalate substrates, using the Magnetron Sputtering tech‐ nique. The ability of acquiring real‐time measurements simultaneously and rapidly at 32 wavelengths at the 3‐6.5 eV spectral region, provided accurately the thin films material response. By the analysis of the measured SE spectra, using the appropriate models, it has been determined in detail the time dependence of thickness and optical parameters of the films, providing significant insight on the ZnO growth mechanisms from the early stages of growth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry studies of In2S3top window and Mo back contacts in chalcopyrite photovoltaics technology
Authors: Marsillac S. , Barreau N. , Khatri H. , Li J. , Sainju D. , Parikh A. , Podraza N. J. , Collins R. W. 
Published: March 2008

AbstractSpectroscopic ellipsometry (SE) was used to characterize the conventional back contact layer (Mo) as well as a novel top window layer (In2S3) for use in chalcopyrite photovoltaics technology. For the Mo back contact,in‐situSE measurements of thin films magnetron sputtered onto glass enabled determination ofεat different thicknesses during growth. The observed strong variations could be understood on the basis of a Drude relaxation time that varies with the Mo film thickness. For the In2S3window layer,ex‐situSE measurements showed critical point structures at 2.77±0.08 eV, 4.92±0.005 eV, and 5.64 ± 0.005 eV, as well as an absorption tail with an onset near 1.9 eV. A comparison of the solar cell performance in simulations using either In2S3or conventional CdS revealed similar quantum efficiencies irrespective of the selected window layer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ ellipsometric studies of formation kinetics of rare earth metal conversion coatings on magnesium alloy
Authors: Li Lingjie , Lei Jinglei , Yu Shenghai , He Donghai , Qu Weijuan , Pan Fusheng 
Published: March 2008

AbstractIn situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol·dm‐3 Ce(NO3)3, La(NO)3 and Sm(NO)3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well‐polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of the bulk conversion solutions upon the coatings formation was recorded. It is confirmed that the reduction of protons leads to the interfacial pH increasing and further results in the precipitation of REM hydroxide gel, which is critical for the REM conversion coatings formation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infrared ellipsometry studies of thermal stability of protein monolayers and multilayers
Authors: Arwin H. , Askendahl A. , Tengvall P. , Thompson D. W. , Woollam J. A. 
Published: March 2008

AbstractMethodology for studies of effects of heating multilayers of human serum albumin (HSA) and anti‐HSA is presented. Multilayers of anti‐HSA were prepared on silicon substrates and studied with infrared spectroscopic ellipsometry equipped with a heat stage. The refractive index N = n + ik and the layer thickness are determined and the amide bands are analyzed. It is found that HSA/anti‐HSA multilayers are stable for shorter times at temperatures above 100 °C, except for small thickness changes. Also pilot studies of effects of heating monolayers of proteins adsorbed on gold substrates is presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of the VBLaST™: a virtual basic laparoscopic skill trainer
Authors: Maciel Anderson , Liu Youquan , Ahn Woojin , Singh T. Paul , Dunnican Ward , De Suvranu 
Published: March 2008

AbstractBackgroundThe FLS training tool box has now been adopted by the Society of Gastrointestinal Endoscopic Surgeons (SAGES) as an official training tool for minimally invasive procedures.MethodsTo overcome the limitations of the physical FLS training tool box, we have developed a Virtual Basic Laparoscopic Skill Trainer (VBLaSTTM) system, which is a 3D simulator that will allow trainees to acquire basic laparoscopic skill.ResultsThe outcome of this work is the development of an integrated visio‐haptic workstation environment including force feedback devices and a stereo display interface whereby trainees can practice on virtual versions of the FLS. Realistic graphical rendering and high fidelity haptic interactions are achieved.ConclusionsSurgical skill training is a long and tedious process of acquiring fine motor skills. It is expected that residents would start on trainers such as VBLaSTTM and after reaching a certain level of competence would progress to the more complex trainers for training on specific surgical procedures. Copyright © 2008 John Wiley & Sons, Ltd.
Computer‐assisted implantology: historical background and potential outcomes—a review
Authors: Azari Abbas , Nikzad Sakineh 
Published: March 2008

AbstractBackgroundThe accurate transfer of preoperatively determined implant positions to the patient mouth is very beneficial to the dental practitioner as well as patients. The objective of this paper was to review the gradual development of computer‐assisted implant surgery.MethodsAll of the major data sources including unpublished data in the internet are consideredResults and ConclusionsComputer‐assisted/‐guided/‐aided implantology has been founded to overcome the errors encountered during implant osteotomies and to position the implants more precisely. The protocols followed by this sophisticated technique are based upon the advocated concept of prosthetic‐driven implantology and CT‐scan analysis recently approved. Although several attempts have been made to improve this approach more and more, little has been done regarding the patient's demands, including cost. The inherent complexity of the techniques and materials utilized necessitates several degrees of training before attempting treatment and must be taken into account. Copyright © 2008 John Wiley & Sons, Ltd.
Oral administration of cyanobacterial bloom extract induced the altered expression of the PP2A, Bax, and Bcl‐2 in mice
Authors: Huang Pu , Zheng Yi‐Fan , Xu Li‐Hong 
Published: March 2008

AbstractThe frequent occurrences of the toxic cyanobacterial (specifically Microcystis aeruginosa) bloom are becoming a global environmental issue. Lots of researches have been focused on the pure cyanobacterial toxins, but little on the natural cyanobacterial bloom. This study was undertaken to investigate the effect of the natural cyanobacterial bloom extract on the expression of proteins, which have been shown to be affected by pure microcystins. In current study, the cyanobacterial bloom extract has been administered orally to ICR mice for 7 days with different dosages. The expression level of PP2A, Bcl‐2, and Bax was measured via western blotting. The results showed that after 7 days of exposure to cyanobacteria extract, in mice liver tissue, the expression level of PP2A andBax was increased significantly between the control and treatment groups, but there is no significant change on the Bcl‐2 expression. This is the first report to describe the altered expression of PP2A in vivo when mice exposure to natural water blooms extract that means many cellular pathways would be interfered via the change of PP2A activity. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.