bluuebunny/crossref_metadata_2025 huggingface dataset:
Al-‘Adl wa-l-Ihsan en España: ¿Un proyecto nacional para un movimiento islámico transnacional?
Authors: Arigita Elena
Published: July 2010

Se examina en este ensayo la evolución reciente de las asociaciones musulmanas en España creadas por inmigrantes marroquíes vinculados al movimiento islámico al-‘Adl wa-l-Ihsan (Justicia y Espiritualidad). Partiendo de las declaraciones de un liderazgo emergente de este movimiento en España, la autora trata de explicar cómo el compromiso político de estas personas y el vínculo espiritual con su Guía marroquí incorporan, al tiempo que reelaboran, elementos del discurso dominante sobre la necesaria adaptación del islam a España. Entrevistas en profundidad con estos activistas revelan cómo los lazos del Movimiento con Marruecos y con la umma (Comunidad universal de creyentes) interactúan con el modo en el que estos musulmanes perciben y se posicionan en el contexto nacional de España.
La revuelta de las “ñatitas”: “Empoderamiento ritual” y ciclo de difuntos en la ciudad de La Paz (Bolivia)
Authors: Fernández Juárez Gerardo
Published: July 2010

La periódica exhumación y traslado de cadáveres constituye un comportamiento ritual de larga duración en los Andes Centrales, tal y como acreditan los “procesos de extirpación de idolatrías” de los siglos XVI y XVII, así como la etnografía contemporánea en relación con la festividad de Todos los Santos. A pesar de la actitud crítica y el celo de la Iglesia Católica contra este tipo de comportamientos ceremoniales “heterodoxos”, contamos con ejemplos especialmente elocuentes que continúan practicándose en la actualidad; es el caso de la llamada “Fiesta de las Ñatitas”, que corresponde al domingo siguiente a la del Primero de Noviembre y que se celebra en el camposanto y en el templo del Cementerio General de La Paz. El actual proceso de “empoderamiento ritual” de los pueblos originarios y los movimientos sociales en Bolivia hace resaltar el alcance significativo de esta fiesta y su éxito rotundo en tiempos de vivo conflicto con los responsables de la Iglesia Católica boliviana.
Los caminos del Wallmapu (País mapuche)
Authors: Vitar Beatriz
Published: July 2010

La autora presenta los principales rasgos del complejo fenómeno de revitalización mapuche en Argentina y Chile, concentrándose en la dimensión política del proceso en el ámbito chileno. En este último, la reafirmación étnica y lingüistica ha conducido a la formación de un movimiento nacionalista mapuche, que aspira al reconocimiento de esta comunidad como una “nación” diferenciada por parte del Estado chileno. Pero este nacionalismo no puede entenderse haciendo abstracción de las condiciones generales en los países en que viven los mapuches, así como en otros (v. g., en Bolivia y en España).
Spectroscopic studies of molecular iodine emitted into the gas phase by seaweed
Authors: Ball S. M. , Hollingsworth A. M. , Humbles J. , Leblanc C. , Potin P. , McFiggans G.
Published: July 2010

Abstract. Time profiles of molecular iodine emissions from seven species of seaweed have been measured at high time resolution (7.5 s) by direct spectroscopic quantification of the gas phase I2 using broadband cavity enhanced absorption spectroscopy. Substantial differences were found between species, both in the amounts of I2 emitted when the plants were exposed to air and in the shapes of their emission time profiles. Two species of kelp, Laminaria digitata and Laminaria hyperborea, were found to be the most potent emitters, producing an intense burst of I2 when first exposed to air. I2 was also observed from Saccharina latissima and Ascophyllum nodosum but in lower amounts and with broader time profiles. I2 mixing ratios from two Fucus species and Dictyopteris membranacea were at or below the detection limit of the present instrument (25 pptv). A further set of experiments investigated the time dependence of I2 emissions and aerosol particle formation when fragments of L. digitata were exposed to desiccation in air, to ozone and to oligoguluronate stress factors. Particle formation occurred in all L. digitata stress experiments where ozone and light were present, subject to the I2 mixing ratios being above certain threshold amounts. Moreover, the particle number concentrations closely tracked variations in the I2 mixing ratios, confirming the results of previous studies that the condensable particle-forming gases derive from the photochemical oxidation of the plant's I2 emissions. This work also supports the theory that particle nucleation in the coastal atmosphere occurs in "hot-spot" regions of locally elevated concentrations of condensable gases: the greatest atmospheric concentrations of I2 and hence of condensable iodine oxides are likely to be above plants of the most efficiently emitting kelp species and localised in time to shortly after these seaweeds are uncovered by a receding tide.
Spatial variability and trends of the rain intensity over Greece
Authors: Kambezidis H. D. , Larissi I. K. , Nastos P. T. , Paliatsos A. G.
Published: July 2010

Abstract. In this study, the spatial and temporal variability of the mean annual rain intensity in Greece are examined during a 41-year period (1962–2002). The meteorological datasets concern monthly rain amounts (mm) and the respective monthly durations (h) recorded at thirty two meteorological stations of the Hellenic National Meteorological Service, which are uniformly distributed on Greek territory, in order to calculate the mean monthly rain intensity. All the rain time series used in the analysis were tested by the application of the short-cut Bartlett test of homogeneity. The spatial distribution of the mean annual rain intensity is studied using the Kriging interpolation method, while the temporal variability, concerning the mean annual rain intensity trends along with their significance (Mann-Kendall test), is analysed. The findings of the analysis show that statistically significant negative trends (95% confidence level) appear mainly in the west sub-regions of Greece, while statistically significant positive trends (95% confidence level) appear in the wider area of Athens and the complex of Cyclades Islands. Further analysis concerning the seasonal rain intensity is needed, because there are different seasonal patterns, taking into account that, convective rain in Greece occurs mainly within the summer season.
Validation of five years (2003–2007) of SCIAMACHY CO total column measurements using ground-based spectrometer observations
Authors: de Laat A. T. J. , Gloudemans A. M. S. , Schrijver H. , Aben I. , Nagahama Y. , Suzuki K. , Mahieu E. , Jones N. B. , Paton-Walsh C. , Deutscher N. M. , Griffith D. W. T. , De Mazière M. , Mittelmeier R. , Fast H. , Notholt J. , Palm M. , Hawat T. , Blumenstock T. , Rinsland C. , Dzhola A. V. , Grechko E. I. , Poberovskii A. M. , Makarova M. V. , Mellqvist J. , Strandberg A. , Sussmann R. , Borsdorff T. , Rettinger M.
Published: July 2010

Abstract. This paper presents a validation study of SCIAMACHY CO total column measurements from the IMLM algorithm using ground-based spectrometer observations from twenty surface stations for the five year time period of 2003–2007. Overall we find a good agreement between SCIAMACHY and ground-based observations for both mean values as well as seasonal variations. For high-latitude Northern Hemisphere stations absolute differences between SCIAMACHY and ground-based measurements are close to or fall within the SCIAMACHY CO 2σ precision of 0.2×1018 molecules/cm2 (~10%) indicating that SCIAMACHY can observe CO accurately at high Northern Hemisphere latitudes. For Northern Hemisphere mid-latitude stations the validation is complicated due to the vicinity of emission sources for almost all stations, leading to higher ground-based measurements compared to SCIAMACHY CO within its typical sampling area of 8×8°. Comparisons with Northern Hemisphere mountain stations are hampered by elevation effects. After accounting for these effects, the validation provides satisfactory results. At Southern Hemisphere mid- to high latitudes SCIAMACHY is systematically lower than the ground-based measurements for 2003 and 2004, but for 2005 and later years the differences between SCIAMACHY and ground-based measurements fall within the SCIAMACHY precision. The 2003–2004 bias is consistent with a previously reported Southern Hemisphere bias based on comparisons with MOPITT CO and is currently under investigation. No other systematic spatial or temporal biases could be identified based on the validation presented in this paper. Validation results are robust with regard to the choices of the instrument-noise error filter, sampling area, and time averaging required for the validation of SCIAMACHY CO total column measurements. Finally, our results show that the spatial coverage of the ground-based measurements available for the validation of the 2003–2007 SCIAMACHY CO columns is sub-optimal for validation purposes, and that the recent and ongoing expansion of the ground-based network by carefully selecting new locations may be very beneficial for SCIAMACHY CO and other satellite trace gas measurements validation efforts.
On transport phenomena and equilibration time scales in thermodenuders
Authors: Saleh R. , Shihadeh A. , Khlystov A.
Published: July 2010

Abstract. This paper presents a theoretical and experimental investigation of thermodenuders that addresses two controversial issues: 1) equilibration time scales and 2) the need for an activated carbon (AC) denuder in the cooling section. We describe a plug flow model for transport phenomena in a TD, which can be used to simulate the rate of vapor build-up in the gas phase and the corresponding change in particle size distribution. Model simulations were found to have excellent agreement with experiments performed with pure and mixed dicarboxylic acid aerosols. Both simulations and experiments showed that the aerosols approached equilibrium within reasonable residence times (15 s–30 s) for aerosol concentrations and size distributions typical for laboratory measurements. However, for size distributions relevant for ambient aerosols, equilibration time scales were much larger than residence times available with current TD designs. We have also performed dimensional analysis on the problem of equilibration in TDs, and derived a dimensionless equilibration parameter which can be used to determine the residence time needed for an aerosol of given size distribution and kinetic properties to approach equilibrium. It is also shown theoretically and empirically that aerosol volatility has no effect on the equilibration time scales. Model simulations and experiments showed that with aerosol size distributions relevant to both ambient and laboratory measurements re-condensation in the cooling section, with and without an AC denuder, was negligible. Thus, there is no significant benefit in using an AC denuder in the cooling section. Due to the risk of stripping volatile material from the aerosol, the use of AC denuders in the cooling section should be avoided. Finally, we present a rationale for why Δ C is the proper measure of volatility, while using mass fraction remaining (MFR) can be misleading.
Groundwater fluctuations in heterogeneous coastal leaky aquifer systems
Authors: Chuang M.-H. , Huang C.-S. , Li G.-H. , Yeh H.-D.
Published: July 2010

Abstract. In the past, the coastal leaky aquifer system, including an unconfined aquifer on the top, a confined aquifer at the bottom, and an aquitard in between, was commonly assumed to be homogeneous and of an infinite extent in the horizontal direction. The leaky aquifer system may however be nonhomogeneous and of a finite extent due to variations in depositional and post depositional processes. Thus, in the paper, the leaky aquifer system is divided into several horizontal regions for simulating the heterogeneity involved in both the confined aquifer and aquitard. A one-dimensional analytical model is developed for describing the head fluctuation in such a heterogeneous leaky aquifer system. The head of the upper unconfined aquifer is assumed to remain constant. It is found that both the length and location of the discontinuous aquitards presented in the coastal area have significant effects on the amplitude and phase shift of the head fluctuation in the confined aquifer. In addition, the influences of both the heterogeneous aquifer and aquitard on the spatial head distribution are investigated.
Seasonal sea level extremes in the Mediterranean Sea and at the Atlantic European coasts
Authors: Tsimplis M. N. , Shaw A. G. P.
Published: July 2010

Abstract. Hourly sea level data from tide gauges and a barotropic model are used to explore the spatial and temporal variability of sea level extremes in the Mediterranean Sea and the Atlantic coasts of the Iberian peninsula on seasonal time scales. Significant spatial variability is identified in the observations in all seasons. The Atlantic stations show larger extreme values than the Mediterranean Sea primarily due to the tidal signal. When the tidal signal is removed most stations have maximum values of less than 90 cm occurring in winter or autumn. The maxima in spring and summer are less than 60 cm in most stations. The wind and atmospheric forcing contributes about 50 cm in the winter and between 20–40 cm in the other seasons. In the western Mediterranean the observed extreme values are less than 50 cm, except near the Strait of Gibraltar. Direct atmospheric forcing contributes significantly to sea level extremes. Maximum sea level values due to atmospheric forcing reach in some stations 45 cm during the winter. During the summer the contribution of the direct atmospheric forcing is between 10–20 cm. The Adriatic Sea shows a resonant behaviour with maximum extreme observed sea level values around 200 cm found at the northern part. Trends in the 99.9% percentiles are present in several areas, however most of them are removed when the 50% percentile is subtracted indicating that changes in the extremes are in line with mean sea level change. The North Atlantic Oscillation and the Mediterranean Oscillation Index are well correlated with the changes in the 99.9% winter values in the Atlantic, western Mediterranean and the Adriatic stations. The correlation of the NAO and the MOI indices in the Atlantic and western Mediterranean is significant in the autumn too. The correlations between the NAO and MOI index and the changes in the sea level extremes become insignificant when the 50% percentile is removed indicating again that changes in extremes have been dominated by changes in the mean sea level.
Ground motion prediction from nearest seismogenic zones in and around Greater Cairo Area, Egypt
Authors:   Abd El-Aziz Khairy Abd El-Aal
Published: July 2010

Abstract. This paper reviews the likely source characteristics, focal source mechanism and fault patterns of the nearest effective seismogenic zones to Greater Cairo Area. Furthermore, Mmax and ground accelerations related to the effective seismic events expected in future from those seismogenic zones are well evaluated. For this purpose, the digital waveform of earthquakes than ML=3 that occurred in and around Greater Cairo Area from 1997 to 2008 which have been recorded by the Egyptian National Seismological Network, are used to study source characterization, focal mechanism and fault pattern of the seismogenic zones around Greater Cairo Area. The ground motions are predicted from seismogenic zones to assess seismic hazard in the northeastern part of Greater Cairo, where three effective seismogenic zones, namely Abou Zabul, southeast Cairo trend and Dahshour area, have the largest effect to the Greater Cairo Area. The Mmax was determined, based upon an empirical relationship between the seismic moment and the rupture length of the fault during the earthquake. The estimated Mmax expected from Abou Zabul, southeast Cairo trend, Dahshour seismic sources are of Mw magnitudes equal to 5.4, 5.1, and 6.5, respectively. The predominant fundamental frequency and soil amplification characteristics at the area were obtained using boreholes data and in-situ ambient noise measurement.
Preventive interventions among children exposed to trauma of armed conflict: a literature review
Authors: Peltonen Kirsi , Punamäki Raija‐Leena
Published: July 2010

Increasing research is available on the preconditions for child mental health and optimal development in traumatic conditions, whereas less is known how to translate the findings into effective interventions to help traumatized children. This literature review analyses the effectiveness of psychosocial preventive interventions and treatments and their theoretical bases among children traumatized in the context of armed conflicts (war, military violence, terrorism and refugee). The first aim is to evaluate the effectiveness of preventive interventions in preventing emotional distress and impairment and promoting optimal emotional‐cognitive and social development. The second task is to analyze the nature of the underlying mechanisms for the success of preventive interventions, and the theoretical premises of the choice of intervention techniques, procedures and tools. We found 16 relevant published studies, but an examination of them revealed that only four of them had experimental designs strong enough that they could be included in the meta‐analysis. While the subjective reports of the researchers suggested that systematic preventive interventions were effective in decreasing PTSD and depressive symptoms among children traumatized due to armed conflict, the more objective results of the meta‐analysis and the weaknesses in designs uncovered during the meta‐analysis undermine such a conclusion. Additionally, a majority of the reported preventive interventions focused only on children's biased cognitive processes and negative emotions, while only a few aimed at influencing multiple domains of child development and improving developmental functioning on emotional, social and psychophysiological levels. It is concluded that substantial additional work needs to be done in developing effective preventive interventions and treatments for children traumatized by exposure to war and violence. Aggr. Behav. 36:95–116, 2010. © 2009 Wiley‐Liss, Inc.
Radical Sources of Design Engineering
Authors: Sobek Werner
Published: July 2010

The German architect and structural engineer, Werner Sobek is internationally renowned for his expertise in lightweight structures ‐ an approach that is epitomised by the dramatic elegance of his glazed House R128. Here, Sobek explains how his practice has extended a highly specialised focus on ultra‐lightweight facades to that of building structures, facade planning, and sustainable and low‐energy solutions, interweaving research and innovation with design and consultancy work. Copyright © 2010 John Wiley & Sons, Ltd.
Structured Becoming: Evolutionary Processes in Design Engineering
Authors: Bollinger Klaus , Grohmann Manfred , Tessmann Oliver
Published: July 2010

Computational design techniques are changing the role of analysis tools in collaborations between architects and engineers. Digital feedback loops of synthesis, analysis and evaluation establish a ‘process of becoming’ in which structural solutions evolve and adapt to specific requirements. Highly differentiated constructions are possible when digital techniques are fully integrated in design and production. Klaus Bollinger, Manfred Grohmann and Oliver Tessmann discuss these novel paradigms in relation to recent projects from engineering office Bollinger + Grohmann. Copyright © 2010 John Wiley & Sons, Ltd.
Weaving Architecture: Structuring the Spanish Pavilion, Expo 2010, Shanghai
Authors: Martínez Calzón Julio , Castañón Jiménez Carlos
Published: July 2010

A complex basket‐like structure woven from lightweight steel and wicker, the Spanish Pavilion for the Expo 2010, in Shanghai, is the site of a unique collaboration between architects EMBT (Enric Miralles and Benedetta Tagliabue) and MC2 Structural Engineers. Here Julio Martínez Calzón and Carlos Castañón Jiménez of MC2 describe how intense dialogue became key to the realisation of the pavilion, as form‐finding and the development of the underlying structural system were equally integral to the design process. Copyright © 2010 John Wiley & Sons, Ltd.
Architectural Geometry as Design Knowledge
Authors: Pottmann Helmut
Published: July 2010

The onset of digital design has enabled a new level of experimentation with free‐form shapes in contemporary architecture, which has made geometry a fertile area of research over the last decade or so. Helmut Pottmann describes how geometry not only has the potential to inform a more exciting generative approach for architects, but can also make design much more construction aware for the whole design team, enabling a wholly digital workflow from design to fabrication. Copyright © 2010 John Wiley & Sons, Ltd.
Materialising Complexity
Authors: Scheurer Fabian
Published: July 2010

The specialist practice designtoproduction consults on the digital production of complex architectural designs. Here, co‐founder Fabian Scheurer charts the relatively recent journey that architecture has taken from the regular to the irregular. He provides a comprehensive account of how this shift to curvilinear and complex forms has impacted on design and production methods, and the strengths and pitfalls of parametric design and CNC fabrication. Copyright © 2010 John Wiley & Sons, Ltd.
Timberfabric: Applying Textile Principles on a Building Scale
Authors: Weinand Yves , Hudert Markus
Published: July 2010

Timber is coming to the fore as a contemporary construction material. Not only sustainable, its suppleness, adaptability and strength make it highly attractive for experimental designers. Yves Weinand founded the interdisciplinary timberfabric research project at IBOIS, the Laboratory for Timber Fabric, at the École Polytechnique Fédérale de Lausanne (EPFL), in order to fully explore innovative timber construction techniques. Here Yves Weinand and Markus Hudert describe the Textile Module, which Hudert developed, in order to investigate timber's ability for ‘social behaviour’, or greater structural strength, once woven into a textile‐like form. Copyright © 2010 John Wiley & Sons, Ltd.
A Deeper Structural Theory
Authors: Rappaport Nina
Published: July 2010

The architectural critic and author Nina Rappaport celebrates a new structural synthesis that takes a holistic approach to tectonics, uniting the bones or structure of a building with its skin. She calls for a new structurally based theory that effectively fuses culture and technology, embracing ‘deep decoration’ and ‘subtle innovation’ and reviving a design tradition that can be traced back to AWN Pugin and John Ruskin. Copyright © 2010 John Wiley & Sons, Ltd.
Digital Solipsisim and the Paradox of the Great ‘Forgetting’
Authors: Spiller Neil
Published: July 2010

Neil Spiller counters the main theme of this issue by questioning the dominant focus on production and new technologies in architectural culture, which places a premium on the generation of ‘ever more gratuitous complex surfaces and structures’. Could this inward‐looking emphasis on process and obsessive love of new technologies be at the expense of the final product? Are we in danger of producing artefacts that lose sight of human expression and poetics in the competitive drive for greater complexity? Are we, in fact, heading towards a great ‘forgetting’ in which humanity is subtracted from the architectural product?
High‐Performance All‐Polymer White‐Light‐Emitting Diodes Using Polyfluorene Containing Phosphonate Groups as an Efficient Electron‐Injection Layer
Authors: Zhang Baohua , Qin Chuanjiang , Ding Junqiao , Chen Lei , Xie Zhiyuan , Cheng Yanxiang , Wang Lixiang
Published: July 2010

We report an efficient non‐doped all‐polymer polymer white‐light‐emitting diode (PWLED) with a fluorescent three‐color, white single polymer as an emissive layer, an ethanol‐soluble phosphonate‐functionalized polyfluorene (PF‐EP) as an electron‐injection/electron‐transport layer, and LiF/Al as a cathode, respectively. The all‐polymer PWLED achieves a peak external quantum efficiency of 6.7%, a forward viewing luminous efficiency of 15.4 cd A−1 and a power efficiency of 11.4 lm W−1, respectively, at a brightness of 347 cd m−2 with Commission Internationale d’Eclairage coordinates of (0.37, 0.42) and color rendering index of 85, which is the best results among the non‐doped PWLEDs. Moreover, this kind of PWLED not only shows excellent color stability, but also achieves high brightness at low voltages. The brightness reaches 1000, 10000, and 46830 cd m−2 at voltages of 4.5, 5.4, and 7.5 V, respectively. The significant enhancement of white‐single‐polymer‐based PWLEDs with PF‐EP/LiF/Al to replace for the commonly used Ca/Al cathode is attributed to the more efficient electron injection at PF‐EP/LiF/Al interfaces, and the coordinated protecting effect of PF‐EP from diffusion of Al atoms into the emissive layer and exciton‐quenching near cathode interfaces. The developed highly efficient non‐doped all‐polymer PWLEDs are well suitable for solution‐processing technology and provide a huge potential of low‐cost large‐area manufacturing for PWLEDs.
Photoswitchable Gas Permeation Membranes Based on Liquid Crystals
Authors: Głowacki Eric , Horovitz Karen , Tang Ching W. , Marshall Kenneth L.
Published: July 2010

We have fabricated switchable gas permeation membranes in which a photoswitchable low‐molecular‐weight liquid crystalline (LC) material acts as the active element. Liquid crystal mixtures are doped with mesogenic azo dyes and infused into commercially available track‐etched membranes with regular cylindrical pores (0.40 to 10.0 μm). Tunability of mass transfer can be achieved through a combination of (1) LC/mesogenic dye composition, (2) surface‐induced alignment, and (3) reversible photoinduced LC‐isotropic transitions. Photo‐induced isothermal phase changes in the imbibed material afford large and fully reversible changes in the permeability of the membrane to nitrogen. Both the LC and photogenerated isotropic states demonstrate a linear permeability/pressure relationship, but they show significant differences in their permeability coefficients. Liquid crystal compositions can be chosen such that the LC phase is more permeable than the isotropic—or vice versa – and can be further tuned by surface alignment. Permeability switching response times are 5 s, with alternating UV and >420‐nm radiation at an intensity of 2 mW/cm2 being sufficient for complete and reversible switching. Thermal and kinetic properties of the confined LC materials are evaluated and correlated with the observed permeation properties. We demonstrate for the first time reversible permeation control of a membrane with light irradiation.
Porous Silicon‐Based Optical Microsensors for Volatile Organic Analytes: Effect of Surface Chemistry on Stability and Specificity
Authors: Ruminski Anne M. , King Brian H. , Salonen Jarno , Snyder Jay L. , Sailor Michael J.
Published: July 2010

Sensing of the volatile organic compounds (VOCs) isopropyl alcohol (IPA) and heptane in air using sub‐millimeter porous silicon‐based sensor elements is demonstrated in the concentration range 50–800 ppm. The sensor elements are prepared as one‐dimensional photonic crystals (rugate filters) by programmed electrochemical etch of p++ silicon, and analyte sensing is achieved by measurement of the wavelength shift of the photonic resonance. The sensors are studied as a function of surface chemistry: ozone oxidation, thermal oxidation, hydrosilylation (1‐dodecene), electrochemical methylation, reaction with dicholorodimethylsilane and thermal carbonization with acetylene. The thermally oxidized and the dichlorodimethylsilane‐modified materials show the greatest stability under atmospheric conditions. Optical microsensors are prepared by attachment of the porous Si layer to the distal end of optical fibers. The acetylated porous Si microsensor displays a greater response to heptane than to IPA, whereas the other chemical modifications display a greater response to IPA than to heptane. The thermal oxide sensor displays a strong response to water vapor, while the acetylated material shows a relatively weak response. The results suggest that a combination of optical fiber sensors with different surface chemistries can be used to classify VOC analytes. Application of the miniature sensors to the detection of VOC breakthrough in a full‐scale activated carbon respirator cartridge simulator is demonstrated.
Electron beam irradiation of LLDPE and PDMS rubber blends: Studies on the physicomechanical properties
Authors: Giri Radhashyam , Sureshkumar M. S. , Naskar K. , Bharadwaj Y. K. , Sarma K. S. S. , Sabharwal S. , Nando G. B.
Published: July 2010

Blends of semicrystalline linear low‐density polyethylene and amorphous polydimethyl siloxane rubber were prepared by varying the blend ratios from 100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70 to 0:100 by melt‐blending technique in an internal mixer under previously optimized process conditions using Taguchi methodology. The molded sheets were subjected to electron beam irradiation under varying radiation doses starting from 100, 200, 300, 400 to 500 kGy in an accelerator. The physicomechanical properties of the blends before and after electron beam radiation have been studied, and the optimum dose required for each blend ratio for optimum physicomechancial properties has been investigated. A radiation dose of 100 to 300 kGy is found to be sufficient for obtaining the best balance in tensile strength and tensile impact strength properties. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:98–107, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20120
Enhancing the scratch resistance of polycarbonate with poly(ethylene oxide)–silica hybrid coatings
Authors: Fabbri Paola , Messori Massimo , Toselli Maurizio , Veronesi Paolo , Rocha João , Pilati Francesco
Published: July 2010

Scratch‐resistant coatings for bisphenol‐A polycarbonate sheets were obtained by the sol–gel synthesis of an organic–inorganic hybrid system based on poly(ethylene oxide) and silica. The organic–inorganic hybrids were thermally cured into hard transparent coatings by using conventional and microwave (MW) ovens. Both techniques proved to be equally efficient in promoting the system's crosslinking, as evaluated by 29Si MAS‐NMR. The MW‐assisted curing, however, was much faster. Photoelasticity analysis showed that MW‐assisted curing causes localized overheating of the samples, inducing a state of residual plane stresses that bring about dimensional instability of the coated material. Instrumented scratch tests for the coated samples revealed an increase of 1 order of magnitude in the minimal load at which a scratch track appears on the sample surface. However, the friction coefficient values for samples with thermally cured coatings were lower than those produced by MW‐assisted curing. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:117–126, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20122
Impact of in‐line atmospheric plasma fluorination of carbon fibers on the performance of unidirectional, carbon fiber‐reinforced polyvinylidene fluoride
Authors: Shamsuddin Siti‐Ros , Ho Kingsley K. C. , Lamoriniere Steven , Lee Adam F. , Bismarck Alexander
Published: July 2010

Unidirectional, carbon fiber‐reinforced polyvinylidene fluoride (PVDF) composites were manufactured using a powder impregnation process with integrated in‐line continuous atmospheric plasma fluorination of carbon fibers to produce unidirectional carbon fiber/PVDF tapes with a fiber volume fraction of 60 ± 2%. Carbon fiber/PVDF tapes were processed into composite laminate test specimens by compression moulding and interface‐dominated composite properties were studied. Short‐beam shear test results showed an improvement of up to 70% for the composite laminates containing atmospheric plasma‐fluorinated T700 carbon fibers with a fluorine content of 3.7 at. %, as determined by X‐ray photoelectron spectroscopy. The flexural strength and modulus of the laminated carbon fiber/PVDF composites containing APF‐treated T700 carbon fibers also increased by 45% and 38%, respectively. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:86–97, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20175
Toughening of basalt fiber‐reinforced composites with a cyclic butylene terephthalate matrix by a nonisothermal production method
Authors: Baets J. , Devaux J. , Verpoest I.
Published: July 2010

The interest in thermoplastic composites is growing because of their advantages over thermosets, as well as their recyclability and higher toughness. The melt viscosity of thermoplastic polymers is very high, which makes fiber impregnation difficult. This difficulty can be overcome by the in situ polymerization with cyclic butylene terephthalate (CBT). However, this leads to a brittle polybutyleneterephthalate when isothermal RTM‐production is applied. To solve this problem, a nonisothermal production process for composites with CBT as matrix material was developed and the influence on the toughness was investigated. In the nonisothermal production process, different cooling rates were applied to examine their influence on the toughness of the produced composites. The difference in composites properties was related to the difference in the degree of crystal perfection, which was investigated by differential scanning calorimetry. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:70–79, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20176
Identification of some optimal parameters to achieve higher laminate quality through tape placement process
Authors: Khan Muhammad Amir , Mitschang Peter , Schledjewski Ralf
Published: July 2010

Investigations of the tape placement process are still underway to achieve the laminate quality comparable with other highly developed composite manufacturing methods, such as autoclave‐based processes. The evaluation of the products and the mechanical properties of the material has revealed regions where some upgrading could bring significant enhancement in performance. This study is concerned with issues related to the characterization of material properties, interlaminar bond development, and ways of optimizing process parameters. These include heating, layup velocity, tool temperature, and consolidation force, which were studied to determine their effects on the mechanical strength of the composites produced. The bonding degree of the laminates was simulated taking into account a combination of process parameters, comparing the predictions with the actual test results. The thermal stability of the polyether ether ketone matrix, in relation to the processing conditions used in the manufacture, and their effects on the interlaminar bonding stability were also investigated and explained. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:98–111, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20177
Numerical simulation of the microscale impregnation in commingled thermoplastic composite yarns
Authors: Gennaro R. , Greco A. , Maffezzoli A.
Published: July 2010

The impregnation of a glass woven fabric with an amorphous polyethylene terephthalate copolymer (PET‐g) matrix was investigated using a finite element (FE) model for interbundle and intrabundle flow of the matrix. Micrographs of samples obtained by film stacking of PET‐g to impregnate the glass fabric have confirmed the occurrence of interbundle and intrabundle flow, taking place as separate steps. On the basis of this evidence, two different mechanisms for the fiber impregnation were postulated. The first flow process is associated with a macroscale interbundle impregnation, whereas the second is associated with microscale intrabundle impregnation. Two different FE models were developed to simulate the microscopic and macroscopic flow of the matrix, considering a large number of different random fiber arrangements. Both models could account for the non‐Newtonian rheological behavior of the thermoplastic matrix. The microscale impregnation of fibers was simulated by using randomly spaced and nonoverlapping unidirectional filaments. The effect of the number of filaments and the number of random distributions necessary to achieve an adequate accuracy of the method was assessed. The results obtained from the simulation showed that at low pressures, the polymer melt exhibits Newtonian behavior, which makes it possible to predict the tow permeability by the Darcy law. A more difficult situation arises at high pressures because of the non‐Newtonian behavior of the melt. This requires the introduction of a value for the permeability that is also dependent on the rheological properties of the melt. The same non‐Newtonian behavior of the matrix was observed for macroscale impregnation of bundles. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:122–130, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20179
Offsetting behavior and the benefits of food safety policies in vegetable preparation and consumption
Authors: Nganje William , Miljkovic Dragan , Ndembe Elvis
Published: July 2010

Outbreaks of foodborne illnesses have an effect on the development of public health policy. Due to safety‐related uncertainties in the food supply chain, various regulatory safety and health policies are implemented to decrease potential harm to likely victims. The expected effect of these food‐safety policies forecasted in terms of reduction in foodborne illnesses, mortality, and food‐related diseases may be overstated if consumers' offsetting behavior is overlooked. Reduction and, in some cases, reversal of direct policy effect may occur. This research tests the presence of dominant or partial offsetting behavior in the preparation and consumption of vegetables if a food‐safety policy such as the Pathogen Reduction/Hazard Analysis and Critical Control Point (PR/HACCP) is mandated in the vegetable sector. Experimental results indicate the presence of dominant offsetting behavior in response to mandatory introduction of PR/HACCP in the vegetable sector. © 2010 Wiley Periodicals, Inc.
Stochastic inventory management for tactical process planning under uncertainties: MINLP models and algorithms
Authors: You Fengqi , Grossmann Ignacio E.
Published: July 2010

We address in this article the mid‐term planning of chemical complexes with integration of stochastic inventory management under supply and demand uncertainty. By using the guaranteed service approach to model time delays in the flows inside the network, we capture the stochastic nature of the supply and demand variations, and develop an equivalent deterministic optimization model to minimize the production, feedstock purchase, cycle inventory, and safety stock costs. The model determines the optimal purchases of the feedstocks, production levels of the processes, sales of final products, and safety stock levels of all the chemicals. We formulate the model as a mixed‐integer nonlinear program with a nonconvex objective function and nonconvex constraints. To solve the global optimization problem with modest computational times, we exploit some model properties and develop a tailored branch‐and‐refine algorithm based on successive piecewise linear approximation. Five industrial‐scale examples with up to 38 processes and 28 chemicals are presented to illustrate the application of the model and the performance of the proposed algorithm. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Short‐term scheduling of a large‐scale oil‐refinery operations: Incorporating logistics details
Authors: Shah Nikisha K. , Ierapetritou Marianthi G.
Published: July 2010

Refineries are increasingly concerned with improving the scheduling of their operations to achieve better economic performances by minimizing quality, quantity, and logistics give away. In this article, we present a comprehensive integrated optimization model based on continuous‐time formulation for the scheduling problem of production units and end‐product blending problem. The model incorporates quantity, quality, and logistics decisions related to real‐life refinery operations. These involve minimum run‐length requirements, fill‐draw‐delay, one‐flow out of blender, sequence‐dependent switchovers, maximum heel quantity, and downgrading of better quality product to lower quality. The logistics giveaways in our work are associated with obtaining a feasible solution while minimizing violations of sequence‐dependent switchovers and maximum heel quantity restrictions. A set of valid inequalities are proposed that improves the computational performance of the model significantly. The formulation is used to address realistic case studies where feasible solutions are obtained in reasonable computational time. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Computing multiple steady states in homogeneous azeotropic and ideal two‐product distillation
Authors: Baharev Ali , Kolev Lubomir , Rév Endre
Published: July 2010

Multiple steady states are typically discovered by tracing a solution path, including turning points. A new technique is presented here that does not follow this approach. The original problem is solved directly, without tracing a solution path. The proposed branch‐and‐prune algorithm is guaranteed to find all solutions automatically. Core components of the framework are affine arithmetic, constraint propagation, and linear programming. The C++ implementation is available as an open‐source solver and has an interface to the AMPL® modeling environment. In certain difficult cases, only continuation methods have been reported to find the unstable solution automatically. The proposed method seems to be the first published alternative method in those cases. Although this article focuses mainly on distillation, the presented framework is fairly general and applicable to a wide variety of problems. Further, computational results are given to demonstrate this. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Real‐time control of a semi‐industrial fed‐batch evaporative crystallizer using different direct optimization strategies
Authors: Mesbah Ali , Huesman Adrie E. M. , Kramer Herman J. M. , Nagy Zoltan K. , Van den Hof Paul M. J.
Published: July 2010

This article presents a model‐based control approach for optimal operation of a seeded fed‐batch evaporative crystallizer. Various direct optimization strategies, namely, single shooting, multiple shooting, and simultaneous strategies, are used to examine real‐time implementation of the control approach on a semi‐industrial crystallizer. The dynamic optimizer utilizes a nonlinear moment model for on‐line computation of the optimal operating policy. An extended Luenberger‐type observer is designed to enable closed‐loop implementation of the dynamic optimizer. In addition, the observer estimates the unmeasured process variable, namely, the solute concentration, which is essential for the intended control application. The model‐based control approach aims to maximize the batch productivity, as satisfying the product quality requirements. Optimal control of crystal growth rate is the key to fulfill this objective. This is due to the close relation of the crystal growth rate to product attributes and batch productivity. The experimental results suggest that real‐time application of the control approach leads to a substantial increase, i.e., up to 30%, in the batch productivity. The reproducibility of batch runs with respect to the product crystal size distribution is achieved by thorough seeding. The simulation and experimental results indicate that the direct optimization strategies perform similarly in terms of optimal process operation. However, the single shooting strategy is computationally more expensive. © 2010 American Institute of Chemical Engineers AIChE J, 57: 1557–1569, 2011
Use of the indirect platelet radioactive antiglobulin test with anti‐IgG and anti‐C3 in immune and nonimmune thrombocytopenias
Authors: Freedman John , Cheong Teresa , Garvey M. Bernadette
Published: July 2010

Indirect platelet radioactive antiglobulin tests using anti‐IgG and anti‐C3 were performed in 483 individuals. The subjects' diagnoses and clinical states were correlated with sensitizing protein (IgG and/or C3). Sensitivity of the technique was increased by increasing the serum to cell ratio and there was good correlation between direct and indirect antiglobulin tests in 56 patients. Seven percent of normal healthy non‐thrombocytopenic untransfused males and 88% of patients in whom autoimmune thrombocytopenia was clinically suspected showed a positive test result. In the indirect antiglobulin test, mean ± SD fg anti‐C3d/platelet was 1.75 ± 0.28 (N = 58) with serum from normal subjects, 3.91 ± 1.86 (N = 123) with serum from patients with idiopathic thrombocytopenic purpura and systemic lupus erythematosus, and 2.78 ± 0.91 (N = 52) with serum from patients with lymphoproliferative disease. The differences were significant with P < 0.001. Levels of bound anti‐IgG were in general accord with those of other reports; there was no significant relationship with serum immunoglobulin levels. When the indirect antiglobulin tests were positive for both IgG and C3, there was a significant correlation between IgG and C3 bound to normal platelets (r = 0.671; P < 0.01). Although sera from 39% of patients whose thrombocytopenia was not initially suspected to be on an autoimmune basis gave a positive test result, indirect platelet radioactive antiglobulin tests using anti‐IgG and anti‐C3 may be convenient tools in the evaluation and follow‐up of immune thrombocytopenias.
Quantitative analysis of limb anomalies in CHARGE syndrome: Correlation with diagnosis and characteristic CHARGE anomalies
Authors: Brock Katharine E. , Mathiason Michelle A. , Rooney Brenda L. , Williams Marc S.
Published: July 2010

CHARGE syndrome was initially not thought to involve the limb. Several subsequent reports have shown that limb anomalies are not uncommon. To date, there have been no quantitative studies of limb anomalies in CHARGE syndrome. This study was designed to answer several questions: Do CHARGE patients with limb anomalies represent a subgroup within CHARGE syndrome? Are there correlations between certain CHARGE syndrome anomalies and limb anomalies? Are there differences between the two genders and associated limb anomalies? Are certain types of limb anomalies seen with increased frequency in CHARGE syndrome? All described patients were categorized utilizing the AI/GEN Model 2 Criteria proposed by Mitchell [1985a: J Med Syst 9:425–435]. Patients with chromosomal anomalies or familial CHARGE were excluded, as were patients with inadequate clinical descriptions, and patients in large series where individual characteristics could not be ascertained. Multivariate analysis was performed. One hundred seventy two patients with definite or probable CHARGE syndrome were analyzed. Sixty‐four (37.2%) of these patients have at least one limb anomaly. Significant positive associations were seen between limb anomalies and ocular coloboma, urinary tract malformations, and genital anomalies. These associations were not significant when the definite or probable patients were analyzed separately, with the exception of genital anomalies in definite CHARGE. Gender differences were also identified. Females with tracheoesophageal fistula/esophageal atresia, or genital anomalies were more likely to have limb anomalies, while some female subgroups had positive associations between urinary tract malformations, or choanal atresia and limb anomalies. Negative associations were also seen with sensorineural hearing loss and facial paralysis. In contrast, males showed a positive association between coloboma and limb anomalies, while subgroup analysis identified positive associations with DiGeorge sequence or genital anomalies and limb anomalies. Limb anomalies are present in just over one‐third of CHARGE syndrome patients. Limb anomalies are seen more frequently in association with certain CHARGE anomalies, and these associations show gender differences. There is not a common limb anomaly seen in CHARGE syndrome. © 2003 Wiley‐Liss, Inc.