bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toughening of polypropylene–ethylene copolymer with nanosized CaCO3 and styrene–butadiene–styrene
Authors: Chen Jianfeng , Wang Guoquan , Zeng Xiaofei , Zhao Hongying , Cao Dapeng , Yun Jimmy , Tan Chee King 
Published: August 2004

AbstractNanocomposites of nanosized CaCO3/polypropylene–ethylene copolymer (PPE) and nanosized CaCO3/PPE/styrene–butadiene–styrene (SBS) were prepared by using a two‐roll mill and a single‐screw extruder. By adding CaCO3 nanoparticles into the PPE matrix, the toughness of the matrix substantially improved. At a nanosized CaCO3 content of 12 phr (parts per hundred PPE resin by weight), the impact strength of CaCO3/PPE at room temperature reached 61.6 kJ/m2, which is 3.02 times that of unfilled PPE matrix. In the nanosized CaCO3/PPE/SBS system, the rubbery phase and filler phase are independently dispersed in the PPE matrix. As a result of the addition of nanosized CaCO3, the viscosity of PPE matrix significantly increased. The increased shear force during compounding continuously breaks down SBS particles, resulting in the reduction of the SBS particle size and improving the dispersion of SBS in the polymer matrix. Thus the toughening effect of SBS on matrix was improved. Simultaneously, the existence of SBS provides the matrix with a good intrinsic toughness, satisfying the condition that nanosized inorganic particles of CaCO3 efficiently toughen the polymer matrix. The synergistic toughening function of nanosized CaCO3 and SBS on PPE matrix was exhibited. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 796–802, 2004
Ultrasonically irradiated emulsion polymerization of styrene in the presence of a polymeric surfactant
Authors: Zhang Jingzhi , Cao Ya , He Yuhui 
Published: August 2004

AbstractA polymeric surfactant based on carboxymethyl cellulose and alkyl poly(etheroxy) acrylate (CMC‐A9) was used in ultrasonically irradiated emulsion polymerization of styrene. Polystyrene nanoparticles (30–60 nm) with high molecular weight were prepared. Compared with the conventional emulsion polymerization, the introduction of CMC‐A9 in the polymerization yielded higher monomer conversion in a shorter time and under lower ultrasonic power output. A single latex particle contained only a few polymer chains with average chain numbers of 2–19. The particle size and polymer chain per particle could be controlled by changing the concentration of CMC‐A9 and SDS. The effect of CMC‐A9 and SDS on ultrasonically irradiated emulsion polymerization kinetics was studied. The results indicated that the ultrasonically irradiated emulsion polymerization had a similar nucleation mechanism to a miniemulsion polymerization system. This is attributed to the high ratio of radicals and a great number of smaller sizes of monomer droplets produced under ultrasonic irradiation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 763–768, 2004
Blend membranes prepared from cellulose and soy protein isolate in NaOH/thiourea aqueous solution
Authors: Chen Yun , Zhang Lina 
Published: August 2004

AbstractWe have successfully prepared a series of blend membranes from cellulose and soy protein isolate (SPI) in NaOH/thiourea aqueous solution by coagulating with 5 wt % H2SO4 aqueous solution. The structure and properties of the membranes were characterized by Fourier transform infrared spectroscopy, ultraviolet‐visible spectrometry, dynamic mechanical thermal analysis, scanning electron microscopy (SEM), transmission electron microscopy, and tensile testing. The effects of SPI content (WSPI) on the structure and properties of the blend membranes were investigated. The results revealed that SPI and cellulose are miscible in a good or a certain extent when the SPI content is less than 40 wt %. The pore structure and properties of the blend membranes were significantly improved by incorporation of SPI into cellulose. With an increase in WSPI from 10 to 50 wt %, the apparent size of the pore (2re) measured by SEM for the blend membranes increased from 115 nm to 2.43 μm, and the pore size (2rf) measured by the flow rate method increased from 43 to 59 nm. The tensile strength (σb) and thermal stability of the blend membranes with lower than 40 wt % of WSPI are higher than that of the pure cellulose membrane, owing to the strong interaction between SPI and cellulose. The values of tensile strength and elongation at break for the blend membranes with 10 wt % of WSPI reached 136 MPa and 12%, respectively. The blend membranes containing protein can be used in water because of keeping σ of 10 to 37 MPa. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 748–757, 2004
Characterizing the measurement precision of thermal resistance measurements
Authors: Engel Jan , van Kempen Joris 
Published: August 2004

AbstractThe measurement process of the thermal interface resistance tester combines physical measurements and computer simulations to obtain the measured value of the thermal resistance of a material. The computer simulation model is calibrated by 14 parameters that have been estimated from various experiments. The estimation errors in these parameters contribute to the measurement error in the thermal resistance. The following research questions were raised: (1) What calibration parameter errors have a large contribution to the thermal resistance error? (2) How does this error depend on the reference value of the thermal resistance measured under standard conditions? The main point in this paper is to show the use of statistical modelling to estimate the effect of the calibration parameter errors on the thermal resistance measurement precision by means of a tolerance design procedure that is based on the model. Our final conclusion is that two out of 14 calibration parameters dominate the thermal resistance error, and that their effects strongly depend on the reference thermal resistance. Copyright © 2004 John Wiley & Sons, Ltd.
A statistical analysis of the customer satisfaction with car dealers
Authors: Roscino Annarita , Pollice Alessio 
Published: August 2004

AbstractIn market research, such as for the measure of the customer satisfaction, data are collected through questionnaires. Responses are often classified into ordered categories, so observed variables are ordinal and the rate of missing data may be very high. In this paper, a method for the analysis of a categorical and incomplete data matrix is proposed. Our methodology is applied to data collected by a market survey of Fiat Auto in order to show the latent dimensions underlying the customer satisfaction with car dealers. After multiple imputation of missing values the polychoric correlation matrix, measuring the manifest variables correlations, is computed and used as a proper input to factor analysis. Two factors underlying the several judgement items are thus obtained and their weights on the global judgement ordinal variable are then estimated by ordered probit regression. Copyright © 2004 John Wiley & Sons, Ltd.
Control charts: a cost‐optimization approach for processes with random shifts
Authors: Zempléni András , Véber Miklós , Duarte Belmiro , Saraiva Pedro 
Published: August 2004

AbstractIn this paper we describe an approach for establishing control limits and sampling times which derives from economic performance criteria and a model for random shifts. The total cost related to both production and control is calculated, based on cost estimates for false alarms, for not identifying a true out of control situation, and for obtaining a data record through sampling. We describe the complete process for applying the method and compare with conventional procedures to real data from a Portuguese pulp and paper industrial plant. It turns out that substantial cost‐reductions may be obtained. Copyright © 2004 John Wiley & Sons, Ltd.
Bayesian reliability analysis of complex repairable systems
Authors: Pievatolo Antonio , Ruggeri Fabrizio 
Published: August 2004

AbstractStemming from a consulting project about a gas distribution network, a new, Bayesian model is proposed to describe failures in a complex, expanding over time, repairable system, which is split into components installed over different years. Both exchangeable and independent Poisson processes, homogeneous in space but not in time, are used to model the components. The model takes also into account missing data, due either to unrecorded early failures or unknown installation dates of failed parts.Actual escape data from a gas distribution network illustrate the implementation of the model, which relies on the use of Markov chain Monte Carlo methods. Copyright © 2004 John Wiley & Sons, Ltd.
Global European portfolio construction: Does a changing volatility structure matter?
Authors: Polasek Wolfgang , Pojarliev Momtchil 
Published: August 2004

AbstractWe propose a multivariate time series model to forecast the returns and volatilities of 15 European financial markets. Using the approach of mean‐variance portfolios we develop several strategies which are based on the predictions of high‐dimensional VAR‐GARCH models for future volatilities. We explore the value of volatility timing strategies by simplifying the forecasting model. One approach for information blocking is based on factor analysis for the returns. Finally we discuss if multivariate volatility timing strategies are successful for beating the benchmark index (the MSCI Europe index). Copyright © 2004 John Wiley & Sons, Ltd.
Spatio‐temporal modelling of corrosion in an industrial furnace
Authors: Little John , Goldstein Michael , Jonathan Philip , den Heijer Kees 
Published: August 2004

AbstractOptimal inspection and maintenance of complex systems in modern industry is important for safety and economic reasons. With appropriate statistical modelling, the utilization of inspection resources and quality of inferences can be greatly improved. Modelling and inspection of a full‐scale industrial furnace subject to corrosion will be considered. A suitable Bayesian spatio‐temporal dynamic linear model is developed for wall thickness, by eliciting the beliefs of experts and incorporating other relevant data for related systems. The model may be used to derive efficient inspection schedules for corrosion detection and we demonstrate the considerable reduction in the inspection burden which the model allows. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of multivariate methods for robust parameter design in sheet metal spinning
Authors: Auer Corinna , Erdbrügge Martina , Göbel Roland 
Published: August 2004

AbstractSheet metal spinning is a very complex forming process with a large number of quality characteristics. Within the scope of a joint project of the Department of Statistics and the Chair of Forming Technology the impact of process parameters (design factors) on important quality characteristics has been investigated both theoretically and experimentally. In the past, every response has been treated individually and uncontrollable disturbances (noise factors) have been neglected. Now this approach has been extended to robust multiresponse parameter design. For this, a review of common multivariate approaches for robust parameter design has been carried out, which also leads to the proposal of some new variants. In addition to the theoretical comparison, the methods were applied to data gained in the sheet metal spinning process. The obtained results were evaluated in terms of applicability, limitations and quality accuracy. Practical experiments confirmed the high degree of efficiency that the finally proposed method based on desirabilities promises. Copyright © 2004 John Wiley & Sons, Ltd.
A model‐based approach to quality control of paper production
Authors: Brown Patrick E. , Diggle Peter J. , Henderson Robin 
Published: August 2004

AbstractThis paper uses estimated model parameters as inputs into multivariate quality control charts. The thickness of paper leaving a paper mill is measured at a high sampling rate, and these data are grouped into successive data segments. A stochastic model for paper is fitted to each data segment, leading to parameter estimates and information‐based standard errors for these estimates. The estimated model parameters vary by more than one can be explained by the information‐based standard errors, suggesting that the ‘true’ underlying parameters are not constant over time. A model is formulated for the true parameters in which the information matrix dictates the distribution for the observed parameters given the true parameters. Copyright © 2004 John Wiley & Sons, Ltd.
Bivariate non‐parametric regression models: simulations and applications
Authors: Durio Alessandra , Isaia Ennio Davide 
Published: August 2004

AbstractThis paper presents a practical procedure for performing non‐parametric bivariate regression analysis. The procedure applies the Nadaraya–Watson local linear kernel estimator with associated bootstrap variability bands whenever the pseudo‐likelihood ratio test rejects the linear regression model hypothesis. Two case studies and simulations are used to demonstrate the proposed technique. Calculations have been performed using the shareware R software. Copyright © 2004 John Wiley & Sons, Ltd.
Plant sensitivity to low intensity 105 GHz electromagnetic radiation
Authors: Tafforeau Marc , Verdus Marie‐Claire , Norris Vic , White Glenn J. , Cole Mike , Demarty Maurice , Thellier Michel , Ripoll Camille 
Published: August 2004

AbstractExposing seedlings of the flax, Linum usitatissimum L., to a variety of weak environmental stresses followed by a 2 day calcium deprivation, triggers the common response of production of epidermal meristems (actively dividing groups of cells) in the hypocotyl, which is the part of the stem between the root and the cotyledons (the pre‐existing leaves in the embryo). This production reaches a plateau of 10–20 meristems after a month in the case of mechanical stimulation and cold shock. Recently, we have shown that radiation from a global system for mobile communication (GSM) telephone also triggers production of meristems with a plateau of around six meristems. Here, we show that a single 2 h exposure to radiation emitted at 105 GHz at non‐thermal levels by a Gunn oscillator induces meristem production with kinetics similar to that induced by weak environmental stimuli and radiation from GSM telephone. Bioelectromagnetics 25:403–407, 2004. © 2004 Wiley‐Liss, Inc.
Generic UMTS test signal for RF bioelectromagnetic studies
Authors: Mbonjo Mbonjo H. Ndoumbè , Streckert J. , Bitz A. , Hansen V. , Glasmachers A. , Gencol S. , Rozic D. 
Published: August 2004

AbstractThis report outlines the characteristics of universal mobile telecommunications system (UMTS) signals and discusses the signal parameters with respect to their possible biological relevance in order to define a generic UMTS test signal (GUS) for experiments aiming at the investigation of biological effects of weak electromagnetic fields. The GUS includes features of a real UMTS signal and especially the characteristics of UMTS, which differ from those of already applied second generation mobile communication systems (GSM 900, DCS1800, PCS1900, IS‐95). It has been specified on the basis of the recommendations of a working group of the German Forschungsgemeinschaft Funk (FGF) with a focus on the mechanisms of UMTS which are responsible for slow term signal contributions, i.e., low frequency variations of the radio frequency (RF) envelope, since the hypothetical possibility of biological relevance of weak electromagnetic fields is often attributed to time variations of the RF envelope with frequencies close to those of natural processes. In this respect, it is also shown that the mandatory power control loop in UMTS gives rise to very strong 1.5 kHz variations on the air interface. Based upon the concept of the GUS, a UMTS test signal generator (GUS6960S) is described. Bioelectromagnetics 25:415–425, 2004. © 2004 Wiley‐Liss, Inc.
Influence of local geomagnetic storms on arterial blood pressure
Authors: Dimitrova S. , Stoilova I. , Cholakov I. 
Published: August 2004

AbstractThis study attempts to assess the influence of local geomagnetic storms at middle latitudes on some human physiological parameters. The blood pressure (bp), heart rate and general well‐being of 86 volunteers were measured, the latter by means of a standardised questionnaire, on work days in autumn, 2001 (1 Oct to 9 Nov), and in spring, 2002 (8 April to 28 May). These timespans were chosen as periods of maximal expected geomagnetic activity (GMA). Altogether, 2799 recordings were obtained and analysed. A four factor analysis of variance (MANOVA) was employed to check the significance of the influence of four factors (local GMA level; sequence of the days of measurements covering up to 3 days before and after geomagnetic storms; sex and the presence of medication) on the physiological parameters under consideration. Post hoc analysis was performed to elicit the significance of differences in the factors' levels. Arterial bp was found to increase with the increase of the GMA level, and systolic and diastolic bp were found to increase significantly from the day before till the second day after the geomagnetic storm. These effects were present irrespective of sex and medication. Bioelectromagnetics 25:408–414, 2004. © 2004 Wiley‐Liss, Inc.
Changes in human EEG caused by low level modulated microwave stimulation
Authors: Hinrikus Hiie , Parts Maie , Lass Jaanus , Tuulik Viiu 
Published: August 2004

AbstractThis study focuses on the effect of low level microwave radiation on human EEG alpha and theta rhythms. During the experiment, 20 healthy volunteers were exposed to a 450 MHz microwaves with 7 Hz on–off modulation. The field power density at the scalp was 0.16 mW/cm2. Signals from the following EEG channels were used: FP1, FP2, P3, P4, T3, T4, O1, and O2. The experimental protocol consisted of one cycle of short term photic and ten cycles of the repetitive microwave stimulation. The changes caused by photic as well as microwave stimulation were more regular on the alpha rhythm. In the majority of cases, photic stimulation caused changes in the EEG energy level in the occipital and microwave stimulation in the frontal region. Our experimental results demonstrated that microwave stimulation effects became apparent, starting from the third stimulation cycle. Changes varied strongly from subject to subject. Therefore, photic and microwave exposure did not cause statistically significant changes in the EEG activity level for the whole group. For some subjects, clear tendencies of changes in microwave on–off cycles were noticeable. Bioelectromagnetics 25:431–440, 2004. © 2004 Wiley‐Liss, Inc.
Alternating extremely low frequency magnetic field increases turnover of dopamine and serotonin in rat frontal cortex
Authors: Sieroń Aleksander , Labus Łukasz , Nowak Przemysław , Cieślar Grzegorz , Brus Halina , Durczok Artur , Zagził Tomasz , Kostrzewa Richard M. , Brus Ryszard 
Published: August 2004

AbstractThe aim of this study was to evaluate the influence of an extremely low frequency sinusoidal magnetic field (ELF MF) with frequency of 10 Hz and intensity of 1.8–3.8 mT on the levels of the biogenic amines dopamine (DA), 3,4‐dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3‐methoxytyramine (3‐MT), 5‐hydroxytryptamine (5‐HT), 5‐hydroxyindolacetic acid (5‐HIAA), and noradrenaline (NA), as well as on DA and 5‐HT turnover in corpus striatum and frontal cortex of adult male Wistar rats. We found that ELF MF exposure for 14 days, 1 h daily, did not influence the level of the examined biogenic amines and metabolites, but increased the rate of synthesis (turnover) of DA and 5‐HT in rat frontal cortex as compared to control, sham exposed rats. On the basis of the present results and our previous findings, extremely low frequency magnetic field (ELF MF) exposure has been found to alter both turnover and receptor reactivity of monoaminergic systems, as well as some behaviors induced by these systems or their agonists and antagonists. Bioelectromagnetics 25:426–430, 2004. © 2004 Wiley‐Liss, Inc.
RF absorption involving biological macromolecules
Authors: Prohofsky E.W. 
Published: August 2004

AbstractThe fundamental intramolecular frequency of a globular protein can be obtained from the measurements of acoustic velocities of bulk protein matter. This lowest frequency for common size molecules is shown to be above several hundred GHz. All modes below this frequency would then be intermolecular modes or bulk modes of the molecule and surrounding matter or tissue. The lowest frequency modes of an extended DNA double helix are also shown to be bulk modes because of interaction with water. Only DNA modes, whose frequency is well above 4 GHz, can be intrahelical modes, that is, confined to the helix rather than in the helix plus surroundings. Near 4 GHz, they are heavily damped and, therefore, not able to resonantly absorb. Modes that absorb radio frequency (RF) below this frequency are bulk modes of the supporting matter. Bulk modes rapidly thermalize all absorbed energy. The implication of these findings for the possibility of athermal RF effects is considered. The applicability of these findings for other biological molecules is discussed. Bioelectromagnetics 25:441–451, 2004. © 2004 Wiley‐Liss, Inc.
902 MHz mobile phone does not affect short term memory in humans
Authors: Haarala Christian , Ek Maria , Björnberg Linda , Laine Matti , Revonsuo Antti , Koivisto Mika , Hämäläinen Heikki 
Published: August 2004

AbstractWe studied the effects of an electromagnetic field (EMF) as emitted by a 902 MHz mobile phone on human short term memory. This study was a replication with methodological improvements to our previous study. The improvements included multi‐centre testing and a double blind design. A total of 64 subjects (32 men) in two independent laboratories performed a short term memory task (n‐back) which poses a varying memory load (0–3 items) on the subjects' memory. They performed the task twice, once each under EMF and sham exposure. Reaction times (RTs) and accuracy of the responses were recorded. The order of exposure and memory load conditions were counterbalanced across subjects and gender. There were no statistically significant differences in performance between the two laboratories. We could not replicate our previous results: the EMF had no effect on RTs or on the accuracy of the subjects' answers. The inability to replicate previous findings could have been caused by lack of actual EMF effects or the magnitude of effects being at the sensitivity threshold of the test used. Bioelectromagnetics 25:452–456, 2004. © 2004 Wiley‐Liss, Inc.