bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal oxidative stability and effect of water on gas transport and mechanical properties in PA6‐EVOH films
Authors: Cerruti Pierfrancesco , Laurienzo Paola , Malinconico Mario , Carfagna Cosimo 
Published: February 2007

AbstractThe thermal oxidative stability and the effect of water on gas transport and mechanical properties of blends of polyamide 6 (PA6) with ethylene‐co‐vinyl alcohol (EVOH) and EVOH modified with carboxyl groups (EVOH‐COOH) have been investigated. The presence of EVOH reduces water vapor and oxygen gas permeability of polyamide, as well as small amounts of EVOH‐COOH further improve barrier properties, especially to oxygen. This has been explained in terms of improved interactions of the blend constituents in the amorphous phase, due to ionic linkages between the polyamide amino groups and the carboxyls of modified EVOH. The permeation to gases was found to increase with the amount of sorbed water. The morphology of the samples was found to have an effect on barrier properties, as the presence of EVOH causes the PA6 α crystalline form to increase, lowering the permeability to oxygen and water vapor. Mechanical properties are strongly affected by water sorption, as tensile modulus and strength decrease with increasing water content. Chemiluminescence (CL), infrared spectroscopy (FTIR), and tensile test were employed in order to assess the correlation between chemical composition and the thermal oxidative stability of the films aged at 110 °C in air. CL experiments suggest that the presence of EVOH and EVOH‐COOH efficiently inhibits the formation of peroxidized species during the processing, and increases the thermal oxidative stability of the films. Infrared spectroscopy showed a build‐up of carbonyl absorption in the range 1700–1780 cm−1, due to the formation of oxidation products, which is greater in the case of the pure polymer. Tensile tests on films revealed a reduction in ductility as a result of ageing for neat PA6, whereas in comparison the blends exhibit a far better long‐term stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 840–849, 2007
Characterization, solution properties, and morphologies of a hydrophobically associating cationic terpolymer
Authors: Zhong Chuanrong , Luo Pingya 
Published: February 2007

AbstractThe acrylamide‐based terpolymers (PADB) with 4‐butylstyrene (BST) as the hydrophobic monomer and dimethyldiallyammonium chloride (DMDAAC) were synthesized by the micellar free radical technique. The polymer was determined by UV, FT‐IR and 1HNMR, and the hydrophobic microblock structure of PADB was characterized successfully by the conventional DSC measurement. The use of DMDAAC improves the water solubility and intermolecular association of terpolymers. The feed amount of BST affects greatly the apparent viscosity of PADB solution. The polymer exhibits good viscosification property, salt resistance, temperature‐thickening, thixotropy, pseudoplastic behavior and shear‐thickening at low shear rate. The apparent viscosities of PADB solution remarkably increase by the addition of a small amount of surfactant. AFM measurements show that hydrophobic aggregates have been formed in 0.1 g dL−1 PADB aqueous solution, indicative of strong associations of hydrophobic groups, which are reinforced with increasing PADB concentration. The microstructures of PADB are disrupted by the addition of small amounts of salt, resulting in the decrease in solution viscosity. However, with increasing NaCl concentration, the tree‐like associating structures are formed, leading to the increase in the solution viscosity of PADB. The AFM results reveal that the solution properties of PADB are due to the associating structures in the aqueous solution and brine solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 826–839, 2007
Voltage‐induced resistivity relaxation in a high‐density polyethylene/graphite nanosheet composite
Authors: Lu Wei , Lin Hongfei , Chen Guohua 
Published: February 2007

AbstractThe resistivity relaxation behavior under applied voltages in a high‐density polyethylene/graphite nanosheet composite was investigated. The influence of applied voltages on the resistivity relaxation was measured by the collection of the electric current passing through the sample and the increasing temperature of the sample. With increments in the voltage, three distinguishable relaxation curves corresponding to different dominating mechanisms were observed. The sawed curve, corresponding to the application of a high voltage, could be attributed to the reorganization of conductive particles induced by the electric field and the destruction of the conductive network due to the thermal expansion of the high‐density polyethylene matrix. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 860–863, 2007
Dynamics of active‐layer detachment failures, Fosheim Peninsula, Ellesmere Island, Nunavut, Canada
Authors: Lewkowicz Antoni G. 
Published: February 2007

AbstractDozens of fresh active‐layer detachments were observed on the Fosheim Peninsula in late‐summer 2005 following one week of high air temperatures and nearly continuous bright sunshine. One of these shallow translational landslides started as a minor movement on an upper, steeper slope segment but over several days its front propagated 250 m downslope at velocities of 2–9 m h−1. A second, smaller active‐layer detachment developed within less than 2 hours and subsequent movement was limited. Effective stress analyses can explain the initiation of these landslides on moderate gradients. Movements across extremely low‐angled slope segments, however, likely require both dynamic loading from the moving mass and very low basal undrained shear strengths produced by high porewater pressures. The lengthy development of the large active‐layer detachment helps explain stratigraphic and morphologic features previously observed in these slope failures. Copyright © 2007 John Wiley & Sons, Ltd.
The effect of transient conditions on an equilibrium permafrost‐climate model
Authors: Riseborough Dan 
Published: February 2007

AbstractEquilibrium permafrost models assume a stationary temperature and snow‐cover climate. With a variable or changing climate, short‐term energy imbalances between the active layer and permafrost result in transient departures from the equilibrium condition. This study examines the effects of such variability on an equilibrium permafrost‐climate model, the temperature at the top of permafrost (TTOP) model. Comparisons between numerical results and temperatures predicted by the TTOP‐model suggest that stationary inter‐annual variability introduces an error in the top‐of‐permafrost temperature obtained with the equilibrium model that is higher where permafrost temperature is close to 0°C, although multi‐year averaging reduces the error to 0.1°C or less. In the presence of a warming trend, the equilibrium model prediction tracked the changing top‐of‐permafrost temperature until permafrost temperatures reached 0°C, after which the equilibrium model produced significant errors. Errors up to 1°C were due to the temperature gradient through the developing talik, and depended on the warming rate, and the thickness of the talik. For all warming rates, the error was largest when the permafrost table was about 4 m below the surface, with the error declining as the permafrost table fell. Copyright © 2007 John Wiley & Sons, Ltd.
Revisiting of a silane explosion in a photovoltaic fabrication plant
Authors: Chang Yo‐Yu , Peng Deng‐Jr , Wu Hong‐Chun , Tsaur Charng‐Cheng , Shen Chun‐Cheng , Tsai Hsiao‐Yun , Chen Jenq‐Renn 
Published: February 2007

AbstractA second possible cause of a previously described silane explosion is proposed based on a more detailed examination of the physical evidence. The explosion and fire occurred in a silane gas room in a photovoltaic fabrication plant. This investigation recommends more research to investigate the characteristics of a silane release and the resulting fires and explosions. Suggestions are also made for a better silane cylinder valve design and cabinet design. Silane leaks are difficult to detect; therefore the recommendations include the need for a silane gas detector to warn the operator when there are leaks. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007.
Cross‐resistance profile of mesosulfuron‐methyl‐resistant Italian ryegrass in the southern United States
Authors: Kuk Yong In , Bugos Nilda R 
Published: February 2007

AbstractDiclofop‐resistant Lolium species (ryegrass) is a major weed problem in wheat production worldwide. This study was conducted to determine the resistance pattern of diclofop‐resistant ryegrass accessions from the southern United States to mesosulfuron‐methyl, a recently commercialized herbicide for ryegrass control in wheat; to determine the cross‐resistance pattern of a Lolium multiflorum Lam. (Italian ryegrass) accession, 03‐1, to acetolactate synthase (ALS) and acetyl‐CoA carboxylase (ACCase) inhibitors; and to determine the resistance mechanism of Italian ryegrass to mesosulfuron‐methyl. Seventeen ryegrass accessions from Arkansas and Louisiana, including standard resistant and susceptible accessions, were used in this experiment. Fourteen of the 17 accessions were more resistant (four‐ to > 308‐fold) to diclofop than the standard susceptible biotype. One accession, 03‐1, was resistant to mesosulfuron‐methyl as well as to other ALS inhibitor herbicides such as chlorsulfuron, imazamox and sulfometuron. Accession 03‐1, however, did not show multiple resistance to the ACCase inhibitor herbicides diclofop, fluazifop, clethodim, sethoxydim and pinoxaden, nor to glyphosate. The in vivo ALS activity of the 03‐1 biotype was less affected by mesosulfuron‐methyl than the susceptible biotype. This indicates that the resistance mechanism of Italian ryegrass to mesosulfuron‐methyl is partly due to an alteration in the target enzyme, ALS. It is concluded that diclofop‐resistant ryegrass in the southern United States can be generally controlled by mesosulfuron‐methyl. However, mesosulfuron‐methyl must be used with caution because not all ryegrass populations are susceptible to it. There is a need for more thorough profiling of ryegrass resistance to herbicides. Copyright © 2007 Society of Chemical Industry
Toxicity and feeding deterrence of crude toxin extracts of Lecanicillium (Verticillium) lecanii (Hyphomycetes) against sweet potato whitefly, Bemisia tabaci (Homoptera: Aleyrodidae)
Authors: Wang Liande , Huang Jian , You Minsheng , Guan Xiong , Liu Bo 
Published: February 2007

AbstractCrude toxins [toxinV3450 and toxinVp28, extracted from Lecanicillium (Verticillium) lecanii (Zimmermann) Gams & Zare strain V3450 and Vp28 respectively] were tested for contact toxicity, feeding deterrence and repellent activity against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Both toxins showed ovicidal activity to eggs, with LC50 values of 447 and 629 mg L−1 respectively. Nymphs of B. tabaci were the most susceptible stages (LC50 values were calculated at 111 mg L−1 for toxinV3450 and 216 mg L−1 for toxinVp28), and adults were the second most susceptible stages (48 h LC50 values were calculated at 178 mg L−1 for toxinV3450 and 438 mg L−1 for toxinVp28). Applied to seedlings at a concentration of 400 mg L−1, the toxins significantly (P < 0.001) reduced the hatching of whitefly eggs and the subsequent survival rate of the nymphs, and the emergence and fecundity of the progeny adults. Both toxins exhibited repellent activity at low concentration (100 mg L−1), with repellency index (RI) values of 0.645 for toxinV3450 and 0.642 for toxinVp28, and antifeedant activity at high concentration (1000 mg L−1) to adults, with antifeedant index (AFI) values of 0.713 for toxinV3450 and 0.749 for toxinVp28. The results of the present study demonstrate the toxicity, repellence and antifeedant properties of the fungi metabolite toxins on B. tabaci, which might develop as environmentally friendly plant protectant(s). Copyright © 2007 Society of Chemical Industry
On the robustness of changes in extreme precipitation over Europe from two high resolution climate change simulations
Authors: Buonomo E. , Jones R. , Huntingford C. , Hannaford J. 
Published: February 2007

AbstractTwo Regional Climate Model (RCM) projections of changes in extreme precipitation over Europe are assessed and compared. This provides insight into the importance of RCM formulation in representing changes in climate extremes at high spatial resolution. The models concerned are two recent Hadley Centre RCMs, HadRM2 and HadRM3, and are applied at a horizontal resolution of approximately 50 km over Europe, nested within the Hadley Centre coupled Atmosphere Ocean General Circulation Model (AOGCM), HadCM2. The simulation periods are thirty years with fixed concentrations of greenhouse gases representing the climate of 1961–1990 and twenty years representing transient climate change for 2080–2100. The use of common boundary conditions to drive the two RCMs allows us to determine whether their different formulations significantly alter the downscaled projections.The RCM simulations of precipitation extremes are compared with observations from a dense rain‐gauge network over Great Britain, aggregated to the grid used by the RCMs. Both RCMs simulate realistically extreme precipitation occurring over timescales of one to thirty days and for return periods of two to twenty years. In particular, relative errors in the magnitude of extreme precipitation are generally no larger than those in the mean. The two regional models show different patterns of errors for daily precipitation extremes, with the main difference in the western and upland areas of Great Britain where they are underestimated in HadRM2 and overestimated in HadRM3. Change in extremes over all land areas in the domain show increases in intensity everywhere (except for the Iberian peninsula and Mediterranean coast) with most of these significant at the 5% level. Projected increases are greatest for those extremes which are the rarest and shortest duration (i.e. the most intense), both in relative and thus absolute terms. The large‐scale patterns of these changes are very similar in the two RCMs implying they are generally robust to the RCM formulation changes. Given the demonstrated quality of the models this enhances our confidence in the projected changes and suggests that they are mainly conditioned by the large‐scale response in the driving GCM. Copyright Crown Copyright 2007. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd
Impact of airborne Doppler lidar observations on ECMWF forecasts
Authors: Weissmann Martin , Cardinali Carla 
Published: February 2007

AbstractDuring the Atlantic THORPEX Regional Campaign (A‐TReC) in autumn 2003, the airborne Doppler lidar of the Deutsches Zentrum für Luft‐ und Raumfahrt (DLR) was used to observe wind in predicted sensitive regions. In eight flights, the system measured a total of 1600 wind profiles that were experimentally assimilated in the global assimilation system at the European Centre for Medium‐Range Weather Forecasts (ECMWF). The present study assesses the impact of these Doppler lidar measurements in Numerical Weather Prediction (NWP). It is shown that lidar observations have a significant impact on the analyses as well as on forecasts owing to high accuracy and spatial resolution. The measurements reduce the errors of the 1–4 day forecasts of geopotential height, wind, and humidity over Europe throughout the troposphere. On average, Doppler lidar measurements reduce the 2–4 day forecast error of geopotential height over Europe by 3%. This is a promising result, considering that observations have been gathered from only 28.5 flight hours. Dropsondes released in the same area as the Doppler lidar was operating show good agreement for measured winds, but smaller analysis impact and less reduction of the forecast error. Copyright © 2007 Royal Meteorological Society
Including Coriolis effects in the Prandtl model for katabatic flow
Authors: Stiperski Ivana , Kavčič Iva , Grisogono Branko , Durran Dale R. 
Published: February 2007

AbstractKatabatic flow down long glaciers in high latitudes experiences deflection due to the Coriolis force. If the Coriolis force is added to the classic Prandtl model for katabatic flow, the cross‐slope wind component does not approach a true steady state, but rather diffuses upwards in time. On the other hand, the down‐slope component and the potential temperature perturbations do reach stationarity on the same time‐scale as in the classic Prandtl model. Numerical and approximate analytic solutions are presented describing this spatio‐temporal behaviour. Both solutions are in accordance with physical intuition. The analytic approximate solution can be useful in boundary‐layer parameterizations and data analysis. Copyright © 2007 Royal Meteorological Society
Using numerical weather prediction to assess climate models
Authors: Rodwell M. J. , Palmer T. N. 
Published: February 2007

AbstractEstimates of climate change remain uncertain—hampering strategic decision making in many sectors. In large part this uncertainty arises from uncertainty in the computational representation of known physical processes. This model component of climate change uncertainty is increasingly being assessed using perturbed model experiments. Some such model perturbations have, for example, led to headline global warming estimates of as much as 12 °C. These experiments consider many differently perturbed versions of a given base model and assess the likelihood of each perturbed model's climate prediction based on how well it simulates present‐day climate. In these experiments, the computational cost of the model assessment is extremely high unless one assumes that the climate anomalies associated with different model perturbations can be combined linearly. Here we demonstrate a different method, which harnesses the power of the data assimilation system to assess directly the perturbed physics of a model. Data assimilation involves the incorporation of daily observations to produce initial conditions (analyses) for numerical weather prediction (NWP). The method used here quantifies systematic initial tendencies in the first few time steps of a model forecast. After suitable temporal averaging, these initial tendencies imply systematic imbalances in the physical processes associated with model error. We show how these tendencies can be used to produce probability weightings for each model that could be used in the construction of probability distribution functions of climate change. The approach typically costs 5% of the cost of a 100‐year coupled model simulation that might otherwise be used to assess the simulation of present‐day climate. Importantly, since the approach is amenable to linear analysis, it could further reduce the cost of model assessment by several orders of magnitude: making the exercise computationally feasible. The initial tendency approach can only assess ‘fast physics’ perturbations, i.e. perturbations that have an impact on weather forecasts as well as climate. However, recent publications suggest that most of the present model parameter uncertainty is associated with fast physics. If such a test were adopted, assessment of the ability to simulate present‐day climate would then only be required for models that ‘pass’ the fast physics test. The study highlights the advantages of a more seamless approach to forecasting that combines NWP, climate forecasting, and all scales in‐between. Copyright © 2007 Royal Meteorological Society
Comments on deriving the equilibrium height of the stable boundary layer
Authors: Steeneveld G. J. , van de Wiel B. J. H. , Holtslag A. A. M. 
Published: February 2007

AbstractRecently, the equilibrium height of the stable boundary layer received much attention in a series of papers by Zilitinkevich and co‐workers. In these studies the stable boundary‐layer height is derived in terms of inverse interpolation of different boundary‐layer height scales, each representing a prototype boundary layer. As an alternative we propose an inverse interpolation of the eddy diffusivities for each prototype before applying the definition of the Ekman layer depth. The new equation for the stable boundary‐layer height improves performance in a comparison against four observational datasets. Copyright © 2007 Royal Meteorological Society
Further comments on the equilibrium height of neutral and stable planetary boundary layers
Authors: Zilitinkevich Sergej , Esau Igor , Baklanov Alexander 
Published: February 2007

AbstractThe height of the neutrally and stably stratified turbulent planetary boundary layers (PBLs) in the atmosphere and hydrosphere is controlled by numerous factors of different natures. The PBL deepening is facilitated by turbulent mixing caused, first of all, by the velocity shear at the surface, and prevented by the Earth's rotation and the negative buoyancy forces caused by the flow–surface interaction and the stable static stability in the free atmosphere above the PBL. The balance between these factors is often complicated by the baroclinic shears and large‐scale vertical motions (usually disregarded in field experiments), not to mention temporal and horizontal variability of natural PBL flow. It is not surprising that until now many alternative (sometimes contradictory) formulations for the stable PBL height have been proposed and no consensus achieved. To the authors' opinion, the most natural way to investigate this complex problem is to consider step by step the PBL height in comparatively simple, basic equilibrium regimes (controlled by limited factors), to develop and to validate theoretical models for these regimes, and only afterwards to switch to general diagnostic (equilibrium) and prognostic (non‐steady) equations. In the present paper, we briefly summarize recent investigations following the above strategy, and present new data supporting our earlier theoretical conclusions and recommendations. We would not recommend using PBL height equations inconsistent with firmly established basic‐regime formulations. Copyright © 2007 Royal Meteorological Society
Flash flood forecasting: What are the limits of predictability?
Authors: Collier C. G. 
Published: February 2007

AbstractFlash floods may occur suddenly and be accompanied by other hazards such as landslides, mud flows, damage to infrastructure and even death. In the UK such events are comparatively rare occurring on average only once or twice per year. Warning systems must depend upon the accurate real‐time provision of rainfall information, high‐resolution numerical weather forecasts and the operation of hydrological model systems in addition to forecast delivery procedures not discussed in this paper. In this paper we review how flash floods are forecast considering the limitations and uncertainty involved in both the meteorological and hydrological aspects of forecasting systems. Data assimilation and the use of ensembles are both key elements across disciplines. Assessing the susceptibility of river catchments to extreme flooding is considered, and statistical methods of estimating the likelihood of extreme rainfall and floods within a changing climate are examined. Ways of constraining flash flood forecasts are noted as one way to improve forecast performance in the future. Copyright © 2007 Royal Meteorological Society