bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative study of the effect of different nanoparticles on the mechanical properties, permeability, and thermal degradation mechanism of HDPE
Authors: Chrissafis K. , Paraskevopoulos K. M. , Tsiaoussis I. , Bikiaris D. 
Published: June 2009

AbstractIn the present study, different series of high‐density polyethylene (HDPE) nanocomposites were prepared by melt mixing on a Haake‐Buchler Reomixer, containing 2.5 wt % of multiwall carbon nanotubes, pristine and modified montmorillonite, surface‐treated and ‐untreated SiO2 nanoparticles. From transmission electron micrographs, it was found that beyond a fine dispersion of nanoparticles into HDPE matrix, there are also some aggregates easily discriminated. As a result, there was a decrease in the tensile and impact strength of most of nanocomposites except Young's modulus, which was increased. Storage modulus as recorded from dynamic mechanical analysis was also increased in all nanocomposites, because HDPE becomes stiffer due to the incorporation of nanoparticles. The nucleation behavior of nanoparticles during crystallization was found to have no obvious effect on melting and crystallization temperature of HDPE. However, a small decrease in the heat of fusion in all nanocomposites was evidenced. Gas permeability of HDPE matrix in O2, N2, and CO2 was reduced in all nanocomposites compared with neat polymer. Thermal stability of HDPE was also enhanced due to the incorporation of different nanoparticles. From the kinetic analysis of thermal decomposition of HDPE, it was concluded that to describe the thermal degradation of HDPE and the studied nanocomposites, two consecutive mechanisms of nth‐order autocatalysis have to be considered. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of poly(trimethylene terephthalate) nanocomposites incorporating multi‐walled carbon nanotubes
Authors: Wu Chin‐San 
Published: June 2009

AbstractPoly(trimethylene terephthalate) (PTT) nanocomposites containing multi‐walled carbon nanotubes (MWNTs) were prepared using a melt‐blending process. Acrylic acid‐grafted PTT (PTT‐g‐AA) and multihydroxyl‐functionalized MWNTs (MWNTs−OH) were used to improve the compatibility and dispersibility of MWNTs within the PTT matrix. The nanocomposites were characterized morphologically by transmission electron microscopy and chemically using Fourier transform infrared absorbance, 13C solid‐state nuclear magnetic resonance, and ultraviolet‐visible spectroscopy. The thermal and mechanical properties of the blends were also evaluated. The functionalized PTT‐g‐AA/MWNT–OH blend showed markedly enhanced thermal and mechanical properties due to the formation of ester bonds from the condensation of the carboxylic acid groups of PTT‐g‐AA with the hydroxyl groups of MWNT–OH. The optimal proportion of MWNT–OH in the blends was 1 wt %. In excess of this amount, compatibility between the organic and inorganic phases was compromised. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of the electron donor structure on the shelf‐lifetime of visible‐light activated three‐component initiator systems
Authors: Kim Dongkwan , Scranton Alec B. , Stansbury Jeffrey W. 
Published: June 2009

AbstractIn this study, we investigated the effect of electron donor structures on the shelf life of three‐component initiator systems which also included methylene blue (MB) as a photosensitizer and diphenyl iodonium salt (DPI) as an electron acceptor. For this research, N‐phenylglycine (NPG), N‐methyldiethanolamine (MDEA), N,N‐diisopropyl‐3‐pentylamine (DIPA), and 1,4‐diazabicyclo[2.2.2]octane (DABCO) were used as electron donors, with different of proton transfer efficiencies and radical/cation persistence. To aid characterization of the shelf‐life or dark storage stability of three‐component initiator systems, the relative polymerization kinetic profile of each freshly prepared initiator system was first obtained using photo‐DSC. The standardized photopolymerization reactions were repeated after various dark storage intervals. Thermal stability of each initiator system was compared by applying a ramped temperature program to monomer samples in the DSC in the dark. To analyze the kinetic changes as a function of storage time more quantitatively, we suggested an equation and characterized the shelf‐lifetime constant (k) of three‐component initiator systems. From the experiments and analysis, we conclude that the order of shelf‐life is consistent with the of radical cation (DH·+) persistence; DABCO > DIPA > MDEA > NPG, and inversely related to the proton transfer efficiency of the electron donor; NPG > MDEA > DIPA > DABCO. The effects of electron donor structures on thermal stability were consistent with the results of kinetic shelf‐life experiments. This investigation provides an effective means to characterize as well as predict shelf lifetimes of initiator systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of conductive polyaniline/nylon‐6 composite films by polymerization of aniline in nylon‐6 matrix
Authors: Nasybulin Eduard , Menshikova Irina , Sergeyev Vladimir , Levon Kalle 
Published: June 2009

AbstractPolyaniline (PANI)/Nylon‐6 composite films were prepared by oxidative polymerization of aniline (ANI) inside host Nylon‐6 film. Such a composite has the desired electro‐active and mechanical properties to serve as a self‐standing functional unit. Comparative studies on sorption of ANI by Nylon‐6 matrix from various ANI containing media were conducted revealing superior ANI uptake from neutral ANI solution in water. ANI content was measured to be as high as 12%. Spectroscopic measurements showed that hydrogen bonding seemed to play important role in ANI sorption by Nylon‐6 matrix. Polymerization was monitored using atomic force microscopy and conductivity measurements. The morphology studies showed the appearance of PANI nanodomains on Nylon‐6 surface in the early stages of the polymerization. Eventually the domains coalesced during polymerization forming a continuous PANI layer. The conductivity measurements confirmed the change of the morphology from isolated islands to continuous conducting surface by drastic increase in conductivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Ageing of polyamide 11 used in the manufacture of flexible piping
Authors: Romão Wanderson , Castro Eustáquio V. R. , Filho Elói A. S. , Guimarães Regina C. L. , Silva Ana L. N. , Teixeira Sylvia C. S. , de Paoli Marco‐A. , de Sena Geovane L. 
Published: June 2009

AbstractThe influence of temperature and pH on the ageing of piping made from polyamide 11 (PA‐11) was studied using water from an oilfield (pH = 5.5) and deionized water (pH = 7.0) with monitoring by corrected inherent viscosity (CIV) measurements. The hydrolytic degradation was more extensive at high temperatures in oilfield water. When the system reaches equilibrium, the pH affects mainly the CIV plateau values. Thermogravimetry, energy‐dispersive X‐ray spectroscopy, differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy measurements were also used to investigate aspects involved in the ageing PA‐11. The hydrolytic degradation of PA‐11 leads to formation of low molar mass compounds, such as oligomers dispersed in the polymeric matrix. This is a process that occurs preferentially in the amorphous domain of PA‐11, which leads to an increase in the degree of crystallinity and the formation of a new γ‐phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of melamine–formaldehyde–polyvinylpyrrolidone polymer resin for better industrial uses over melamine resins
Authors: Singh Man , Kumar Vinod 
Published: June 2009

AbstractMelamine–formaldehyde–polyvinylpyrrolidone (MFP) polymer resin was prepared with 1 : 16 : 1 ratios of melamine, formaldehyde (CH2O), and polyvinylpyrrolidone amounts, respectively, by condensation polymerization at 6.9 pH. Structures were determined with IR, 1H‐NMR, and 13C‐NMR spectroscopies. Chemical shifts (δ, ppm) were analyzed with singlet at δ 4.5, duplet from 3.13 to 3.17 and a quartet at 1.5 to 2.2 ppm for methylene (CH2) bridging group, pyrrolidone, and polyvinyl constituents. The 3389.25, 1290.38, and 1655.28 cm−1 stretching frequencies of N, CH and COO groups, respectively, were noted on FTIR spectrum. The CN melamine units reacted with CH2O to adjoin with polyvinylpyrrolidone (PVP). An average viscosity molecular weight ($\bar{M}$v) 57,000 g mol−1 was obtained with Mark–Houwink–Sakurada equation. The chemical shift of N(CH2O)2Cpyrrolidone ring on 13C‐NMR spectra was shifted toward lower magnetic field at 175.18 ppm. The resin was partially miscible with water thereby densities and viscosities of aqueous solutions were measured at 298.15 K temperature. It showed higher densities and viscosities than those of water. The resin developed exceptionally higher adhesive strengthen when its 62.29‐μm uniform thin film was applied on surfaces of wooden strips. The resin showed micellar behavior at about 0.009 g/100 mL aqueous solution. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The physiological role of hormones in saliva
Authors: Gröschl Michael 
Published: June 2009

AbstractThe assessment of hormones in saliva has gained wide acceptance in clinical endocrinology. To date, there is no hypothesis as to why some hormones can be found in saliva, while others cannot, and whether there is a physiological consequence of this fact. A number of carefully performed studies give examples of important physiological hormonal activity in saliva. Steroids, such as androgens, act as pheromones in olfactory communication of various mammalian species, such as facilitating mating behavior in swine or serving as odor cues for rodent nestlings. Salivary peptide hormones, such as epidermal growth factor (EGF) and transforming growth factor‐α (TGF‐α), and amines such as melatonin, are involved in the regulation of inflammatory processes and in the promotion of cell proliferation, and contribute to a rapid wound healing in the oropharyngeal epithelia. Current data provide evidence of the involvement of salivary cytokines, such as interleukin‐8 and leptin, in tumorgenesis in the oral cavity and the salivary glands. The tumor tissues express and release significantly more of these cytokines than healthy glands. Consequently, the assessment of salivary hormone profiles may provide promising targets for diagnostic tumor markers.
Regulation, necessity, and the misinterpretation of knockouts
Authors: Davies Jamie 
Published: June 2009

AbstractMuch contemporary biology consists of identifying the molecular components that associate to perform biological functions, then discovering how these functions are controlled. The concept of control is key to biological understanding, at least of the physiological kind; identifying regulators of processes underpins ideas of causality and allows complicated, multicomponent systems to be summarized in relatively simple diagrams and models. Unfortunately, as this article demonstrates by drawing on published articles, there is a growing tendency for authors to claim that a molecule is a ‘regulator’ of something on evidence that cannot support the conclusion. In particular, gene knockout experiments, which can demonstrate only that a molecule is necessary for a process, are all too frequently being misinterpreted as revealing regulation. This logical error threatens to blur the important distinction between regulation and mere necessity and therefore to weaken one of our strongest tools for comprehending how organisms work.
Corporate sustainability and innovation in SMEs: Evidence of themes and activities in practice
Authors: Bos‐Brouwers Hilke Elke Jacke 
Published: June 2009

AbstractRecently, innovation processes towards sustainable development have received increasing attention in academic literature. This research introduces the combination of insights from innovation theory, sustainable development practice and small business characteristics to unlock new knowledge on factors that influence the translation of sustainable innovation within small and medium‐sized enterprises (SMEs) into practice. The sustainability themes and activities as described for large companies (i.e. in the sustainability reporting and management literature) were used as starting point in this study. It presents empiric results of the PRIMA Project conducted within the rubber and plastics industry (RPI) on sustainable innovation activities.It will show that many sustainable innovations are directed at the improvement of technological processes (eco‐efficiency) and to lower costs of production. These innovations can be seen as incremental. Companies with sustainability integrated in their orientation and innovation processes show value creation: the development of products new to the market (radical innovations) and cooperation with stakeholders. The PRIMA project shows that more insight in SME innovative characteristics and (e)valuation of sustainable innovation efforts provides opportunities to improve the sustainability performance of SMEs. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
How do institutional shareholders manipulate corporate environmental strategy to protect their equity value? A study of the adoption of ISO 14001 by Egyptian firms
Authors: Wahba Hayam 
Published: June 2009

AbstractTheoretical as well as empirical evidence regarding the influence of institutional ownership on corporate environmental strategy not only is inconclusive but also reflects experience from either the Anglo‐American context or other developed countries. The underlying assumption of most of this literature is that institutional shareholders are always ‘active’ or ‘passive’ in their actions towards corporate environmental strategy. However, this study argues that this relationship might be moderated by various motivations such as legitimizing existence and operations, conforming with industry norms or lessening managerial entrenchment. Econometric analysis, using a sample of Egyptian firms, as hypothesized, demonstrated that institutional ownership exerted positive and significant effects on a corporation's tendency to adopt environmental management standards only when financial resources are available and investment opportunities are limited. A possible explanation of this finding is that Egyptian institutional investors are more likely to use corporate environmental responsibility to offset their inability to confront managerial discretionary power. An implication of this finding is that not only will different types of stakeholder ask for different levels of social and environmental responsibility, but also the same type of stakeholder may ask for different levels of social and environmental responsibility in different contexts. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Teaching ferroresonance in power system to undergraduate students by using MATLAB–SIMULINK
Authors: Vahidi B. , Abandansari A. Haghani 
Published: June 2009

AbstractAccurate knowledge characteristics of a power system are very essential to have an idea of its operation conditions. The ferroresonant circuit exhibits oscillations characterized by frequency that is in accordance to the voltage applied on, and the currents circulating through the components of the circuit. The dominant frequency of these periodic oscillations could be the network frequency (fundamental ferroresonance) or a fraction of it (sub‐harmonic ferroresonance). This phenomenon (both fundamental and sub‐harmonic ferroresonance) is characterized by overvoltages or overcurrents, which may provoke the equipment damage and malfunctioning of the protective devices. The article presents an approach to teaching high voltage laboratory using specially designed exercises that can be done using MATLAB 6.5. This article present a MATLAB based technology to simulate ferroresonance in power system. Evaluation of the simulation with more than 30 students is very positive in terms of their developing confidence in and understanding of this simulation. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 347–357, 2011
Structure–Property Relationships of a Class of Carbamate‐Based Fatty Acid Amide Hydrolase (FAAH) Inhibitors: Chemical and Biological Stability
Authors: Vacondio Federica , Silva Claudia , Lodola Alessio , Fioni Alessandro , Rivara Silvia , Duranti Andrea , Tontini Andrea , Sanchini Silvano , Clapper Jason R. , Piomelli Daniele , Mor Marco , Tarzia Giorgio 
Published: June 2009

AbstractCyclohexylcarbamic acid aryl esters are a class of fatty acid amide hydrolase (FAAH) inhibitors, which includes the reference compound URB597. The reactivity of their carbamate fragment is involved in pharmacological activity and may affect their pharmacokinetic and toxicological properties. We conducted in vitro stability experiments in chemical and biological environments to investigate the structure–stability relationships in this class of compounds. The results show that electrophilicity of the carbamate influences chemical stability, as suggested by the relation between the rate constant of alkaline hydrolysis (log kpH9) and the energy of the lowest unoccupied molecular orbital (LUMO). Introduction of small electron‐donor substituents at conjugated positions of theO‐aryl moiety increased the overall hydrolytic stability of the carbamate group without affecting FAAH inhibitory potency, whereas peripheral non‐conjugated hydrophilic groups, which favor FAAH recognition, helped decrease oxidative metabolism in the liver.
Dynamic Transport in Li‐Conductive Polymer Electrolytes Plasticized with Poly(ethylene glycol)–Borate/Aluminate Ester
Authors: Kaneko Fuminari , Wada Shinta , Nakayama Masanobu , Wakihara Masataka , Kuroki Shigeki 
Published: June 2009

AbstractThe addition of plasticizers into Li+‐conductive solid polymer electrolytes (SPEs) is a commonly known technique to enhance the ionic conductivity. Among the used plasticizers, alkoxides of group‐13 elements [such as poly(ethylene glycol) (PEG)–borate ester] are promising candidates due to the Lewis acidity of the elements of this group (i.e. B, Al, and so on), which interact with the anions and may increase the degree of dissociation of the salts and the transport number of the SPEs. By means of pulsed‐gradient stimulated‐echo NMR (PGStE‐NMR) and AC impedance measurements, we investigate the effect of Lewis acidity originated from group‐13 elements on the transport number and the dissociation rate of SPEs containing various plasticizers. Our results show that the degree of salt dissociation is significantly enhanced by the addition of plasticizers including group‐13 elements, whereas only a small or negligible increase of the transport number is observed for these SPEs. We infer that the plasticizers exhibiting Lewis acidity associate with the anions, and that the associated pairs can migrate in the SPEs as fast as free anions, which results in a lower transport number than expected.
The implementation of socially responsible purchasing
Authors: Leire Charlotte , Mont Oksana 
Published: June 2009

AbstractSocial and ethical issues in the supply chain are gaining importance in all types of organizations. Therefore some public and private organizations have already started to introduce socially responsible purchasing practices. However, current practices are limited and seem unsystematic. There is also a difference between few front‐running organizations and the rest. It is therefore useful at this early stage to disseminate the knowledge and experiences based on the best‐performing organizations. This paper does that by developing a model of the socially responsible purchasing process that is based on the empirical and secondary data. The model reveals the five elementary steps that are necessary in the implementation of systematic socially responsible purchasing practices: developing internal policies; setting purchasing criteria that regard social issues; applying assurance practices; managing supplier relations; and building internal capacity. The model also points to the different activities in the process and their associated challenges. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Ecohydrology of dry regions of the United States: precipitation pulses and intraseasonal drought
Authors: Lauenroth William K. , Bradford John B. 
Published: June 2009

AbstractDistribution of precipitation event sizes and interval lengths between events are important characteristics of arid and semi‐arid climates. Understanding their importance will contribute to our ability to understand ecosystem dynamics in these regions. Our objective for this paper was to present a comprehensive analysis of the daily precipitation regimes of arid and semi‐arid locations of the United States. We collected 30 years of daily precipitation and temperature data from 289 sites in the intermountain zone and 240 sites in the Great Plains for our analysis. The daily precipitation regimes at all sites were dominated by the smallest event sizes and the shortest intervals between events. Great Plains sites on average had more small events and more short intervals than sites in the intermountain zone. In both regions, small events and short intervals were significantly negatively correlated to all other sizes suggesting they were useful for characterizing precipitation regimes. Both the smallest precipitation events and the shortest intervals between precipitation events increased as mean annual temperature decreased. Small events were negatively, but short intervals were positively related to mean annual precipitation. Additional analysis of Great Plains data suggested both quantitative and qualitative differences between precipitation regimes in wet and dry climates. These differences are attributable in large part to the differences in the relationship between precipitation and the evaporative demand of the atmosphere between the semi‐arid and sub‐humid portions of the Great Plains. Copyright © 2009 John Wiley & Sons, Ltd.
Hydrological behaviour of grasslands of the Sandhills of Nebraska: water and energy‐balance assessment from measurements, treatments, and modelling
Authors: Sridhar Venkataramana , Wedin David A. 
Published: June 2009

AbstractUnderstanding energy and water balance processes in the Sandhills is crucial to assess the land–atmosphere feedback effects. The Sandhills located in western Nebraska covers a vast grassland ecosystem with limited variability in vegetation and soil. However, the combined effect of topography, land cover, and micrometeorology by subjecting the land surface to various disturbances and treatments is rarely studied. The NOAH Land Surface Model (LSM) was used to estimate net radiation, latent, sensible, and ground heat (GH) fluxes as well as water balance components for two growing seasons between 2005 and 2006 in various plots at the Grasslands Destabilization Experimental (GDEX) site where these plots were subjected to four different treatments and located at two topographical locations, namely high and low positions. The simulated results of net radiation and GH fluxes correlated well with measurements. While the amount of precipitation received was between 900 and 1000 mm for both seasons, on a daily and sub‐daily time scale the partitioning of net radiation into latent, sensible, and GH fluxes showed high variability across the plots, primarily driven by vegetation and soil moisture. Total evapotranspiration and soil moisture averages suggested the influence of vegetation and the timing of precipitation also in controlling various land surface processes in the Sandhills. This study provides a framework for using the LSM to quantify the feedback effects and emphasizes the importance of microtopography and land treatments in the model environment. Copyright © 2009 John Wiley & Sons, Ltd.