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Processing Procedures (processing + procedure)
Selected AbstractsThe Impact of Interfacial Mixing on Förster Transfer at Conjugated Polymer HeterojunctionsADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Anthony M. Higgins Abstract Neutron reflectivity and photoluminescence measurements are reported on bilayers of polyfluorene-based conjugated polymers. By using a novel thermal processing procedure it is possible to control the width of the interface between poly(9,9-dioctylfluorene) (F8) and poly(9,9-dioctylfluorene- alt -benzothiadiazole) (F8BT), and measure the impact of interfacial roughness on the resonant energy transfer of excitons at the interface (Förster transfer). It is found that increasing the root mean square (rms) roughness of the F8/F8BT interface over the range of ,1,nm to ,5,nm leads to a greatly enhanced Förster transfer from F8 to F8BT molecules. By comparing photoluminescence measurements with simple calculations it is concluded that the level of enhancement of the F8BT peak at rough interfaces can only be adequately explained if mixing of F8 and F8BT at a molecular level dominates over the interfacial roughness due to thermally excited capillary waves. [source] Comparability of transfer function resultsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2006J. Christian Abstract The transfer function (TF) is a comparative method to monitor the mechanical condition of transformer windings. To perform on-site diagnosis a high reproducibility of TF results is required. Consequently, there are certain restrictions for the determination of the TF using time domain records. This paper describes the effect of different signal processing procedures on the results of TF calculations. Window functions, digital filters, length and treatment of pre-trigger samples are aspects of special interest for the application of the TF method. Additionally, condition parameters of the device under test affect the results of TF measurements. The correlation of transformer temperatures and TF characteristics has been investigated as well as the dielectric effect of the insulating oil and the position of the tap changer. Finally, the effect of different test set-up concepts is presented. Copyright © 2005 John Wiley & Sons, Ltd. [source] Synchrotron texture analysis with area detectorsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2003H.-R. Wenk The wide availability of X-ray area detectors provides an opportunity for using synchrotron radiation based X-ray diffraction for the determination of preferred crystallite orientation in polycrystalline materials. These measurements are very fast compared to other techniques. Texture is immediately recognized as intensity variations along Debye rings in diffraction images, yet in many cases this information is not used because the quantitative treatment of texture information has not yet been developed into a standard technique. In special cases it is possible to interpret the texture information contained in these intensity variations intuitively. However, diffraction studies focused on the effects of texture on materials properties often require the full orientation distribution function (ODF) which can be obtained from spherical tomography analysis. In cases of high crystal symmetry (cubic and hexagonal) an approximation to the full ODF can be reconstructed from single diffraction images, as is demonstrated for textures in rolled copper and titanium sheets. Combined with area detectors, the reconstruction methods make the measurements fast enough to study orientation changes during phase transformations, recrystallization and deformation in situ, and even in real time, at a wide range of temperature and pressure conditions. The present work focuses on practical aspects of texture measurement and data processing procedures to make the latter available for the growing community of synchrotron users. It reviews previous applications and highlights some opportunities for synchrotron texture analysis based on case studies on different materials. [source] Localization of mobile robots: Development and comparative evaluation of algorithms based on odometric and inertial sensorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2005G. Ippoliti An autonomous mobile robot must be able to elaborate the measures provided by the sensor equipment to localize itself with respect to a coordinate system. The precision of the location estimate depends on the sensor accuracy and on the reliability of the measure processing algorithm. The purpose of this article is to propose a low cost positioning system using internal sensors like odometers and optical fiber gyroscopes. Three simple localization algorithms based on different sensor data processing procedures are presented. Two of them operate in a deterministic framework, the third operates in a stochastic framework where the uncertainty is induced by sensing and unmodeled robot dynamics. The performance of the proposed localization algorithms are tested through a wide set of laboratory experiments and compared in terms of localization accuracy and computational cost. © 2005 Wiley Periodicals, Inc. [source] Design of Ceramic Materials for Chemical Sensors: Effect of SmFeO3 Processing on Surface and Electrical PropertiesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2001Hiromichi Aono Perovskite-type SmFeO3 powders were prepared by the thermal decomposition of a heteronuclear complex, Sm(Fe(CN)6)·4H2O and by solid-state reaction between the corresponding single oxides, Sm2O3 and Fe2O3. The thermal decomposition behavior of the complex was studied by thermogravimetric analysis. X-ray diffractometry was used to investigate the structure of the products from the complex thermal decomposition and the formation of SmFeO3 from the oxide mixture. Powders prepared by both methods were used to deposit thick films onto alumina substrates with comb-type gold electrodes. The microstructure and chemical homogeneity of the film surfaces were investigated by scanning electron microscopy and Auger electron spectroscopy. Thick SmFeO3 single-phase films having a homogeneous elemental distribution on the surface were obtained when powder prepared by thermal decomposition of the complex was used for deposition, even when the powder was fired at low temperature (800°C). Surface chemical analysis was performed by X-ray photoelectron spectroscopy (XPS). The O 1s XPS line was deconvoluted into two peaks, attributed to adsorbed oxygen (Oad) and oxygen in the lattice (Olattice). Quantitative analysis showed that the surface coverage of iron, expressed as Fe/(Fe + Sm), was larger for the films prepared using the solid-state reacted powder. Although the Olattice/(Fe + Sm) atomic ratio was not influenced by the processing procedures (and, thus, by iron surface coverage), the amount of Oad decreased with increasing iron surface coverage. A model of the SmFeO3 surface was used to determine that the outermost layer of the perovskite-type SmFeO3 prepared from the complex consisted mainly of samarium ions that could each bond four adsorbed oxygen ions. A single oxygen ion could adsorb onto an iron ion, and therefore, the content of adsorbed oxygen was lower for the film prepared from the solid-state reacted powders, which showed larger iron surface coverage. Electrical conductance measurements, performed with increasing temperature in different gaseous environments, confirmed these findings. Higher conductances and lower activation energies were observed for the films with larger samarium surface coverage. [source] Pesticide residues in field-sprayed and processed fruits and vegetablesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2004María Jesús Chavarri Abstract This study was initiated to determine what residues of six insecticides (organochlorine, organophosphorus and pyrethroids) and four dithiocarbamate fungicides remained on raw agricultural commodities after harvest and to study the effect of the subsequent commercial processing on the residues. Sprayed crops of tomatoes, red peppers, asparagus, spinach, artichokes and peaches harvested after controlled field trials contained residues well below the maximum residue levels, except for lindane in tomatoes and acephate in artichoke. Commercial processing procedures led to large reductions in residue levels in the finished products. Washing removed all residual lindane, chlorpyrifos and cypermethrin from tomatoes. Chlorpyrifos residues were reduced by 67% during wood-fire roasting of peppers, and subsequent peeling removed all the remains. Peeling and blanching of asparagus reduced chlorpyrifos concentrations to undetectable levels. Processing of artichokes eliminated acephate and chlorpyrifos after blanching. Acephate in peaches survived successive processing steps until the final heat process that destroyed remaining residues. The net results can contribute to assure the consumer of a safe wholesome food supply. Copyright © 2004 Society of Chemical Industry [source] Input and SLA: Adults' Sensitivity to Different Sorts of Cues to French GenderLANGUAGE LEARNING, Issue S1 2005Susanne E. Carroll All second language (L2) learning theories presuppose that learners learn the target language from the speech signal (or written material, when learners are reading), so an understanding of learners' ability to detect and represent novel patterns in linguistic stimuli will constitute a major building block in an adequate theory of second language acquisition (SLA) input. Pattern detection, a mainstay of current connectionist modeling of language learning, presupposes a sensitivity to particular properties of the signal. Learning abstract grammatical knowledge from the signal presupposes, as well, the capacity to map phonetic properties of the signal onto properties of another type (segments and syllables, morpheme categories, and so on). Thus, even seemingly "simple" grammatical phenomena may embody complex structural knowledge and be instantiated by a plethora of diverse cues. Moreover, cues have no a priori status; a phenomenon of a given sort takes on a value as a cue when acquisition of the grammatical system reveals it to be useful. My study deals with initial sensitivity to cues to gender attribution in French. Andersen (1984) asked: "What's gender good for anyway?" One answer comes from a number of studies, done mostly in the last 20 years, of gender processing by both monolingual and bilingual speakers (among many others, Bates, Devescovi, Hernandez, & Pizzamiglio, 1996; Bates & Liu, 1997; Friederici & Jacobsen, 1990; Grosjean, Dommergues, Cornu, Guillemon, & Besson, 1994; Guillemon & Grosjean, 2001; Taft & Meunier, 1998). These studies provide evidence that in monolinguals and early (but not late) L2 learners, prenominal morphosyntactic exponents of gender prime noun activation and speed up noun recognition. Over the same period, a growing number of studies detailing the course of L2 gender acquisition for a variety of different target languages and learner types (e.g., Bartning, 2000; Chini, 1995; Dewaele & Véronique, 2000; Granfeldt, 2003; Hawkins & Franceschina, 2004) have provided support for the hypothesis that developmental paths differ for early and later learners of gender. Yet despite its obvious importance to SLA theorizing, few studies have dealt directly with adult learners' ability to detect and analyze potential cues to gender at the initial stage of exposure to the L2 (and this despite considerable discussion in recent years of the nature of the "initial state" of L2 learning). The study reported on in this article, which was actually conducted in the late 1980s, was an attempt to shed some light on what the beginning learner can do with the gender attribution problem. This study was, at that time, and is even now, an anomaly; most research dealing with "input" provided descriptions of what people say to learners, not what learners can perceive and represent. Indeed, most studies that shed light on the initial analytical capacities of absolute beginners were concerned with "perceptual" learning, that is, with the acquisition of phonetic or phonological distinctions (e.g., Broselow, Hurtig, & Ringen's [1987] study of tone learning or various studies on the perception of the /r/ vs. /l/ phonemes in American English by Japanese speakers). In this update, it is therefore worth mentioning Rast's (2003) dissertation and Rast and Dommergues (2003), which is based on it, which examined the results of the first 8 hr of instructed learning of Polish by francophone adults. My study asked if anglophone adults, with little or no prior exposure to French, given auditory stimuli, were equally sensitive to phonological, morphosyntactic, or semantic cues to French gender classes. The issue of what learners can detect in the signal and encode is an empirical one. I presented 88 adult English speakers with highly patterned data in list form, namely, auditory sequences of [Det + N]French + translation equivalentEnglish forms. The patterns, all true generalizations, were drawn from linguistic descriptions of French. These cues are believed by grammarians of the language to be "psychologically real" to native speakers. I then measured in 3 different ways what my participants had acquired. Given the extreme limitations on the input (no visual supports to identify referents of names), the participants performed pretty well. Moreover, they proved to be highly sensitive to "natural" semantic and morphological patterns and could generalize accurately from learned instances to novel exemplars. These patterns, however, are not directly instantiated in the speech signal; they are abstractions imposed on the stimuli by human linguistic cognition. Moreover, although it would be inaccurate to describe the learning patterns as "transfer"(because English nouns have no gender feature), prior knowledge seemed to be implicated in the results. Above all, these Anglophones appear to perceive the gender learning problem as a semantic one and to make use of "top-down" information in solving it. It follows that the pattern detection that they can do when listening to speech is clearly biased by what they already know. These results, therefore, provide support for hypotheses that the initial state is to be defined in terms of the transfer of first language (L1) grammatical knowledge and/or the transfer of L1-based processing procedures. [source] Processing Constraints, Categorial Analysis, and the Second Language Acquisition of the Chinese Adjective Suffix - de(ADJ)LANGUAGE LEARNING, Issue 3 2004Yanyin Zhang The study investigates the second language (L2) acquisition of the adjective marker - de(ADJ) in Chinese. It explores the interaction between processing constraints as represented in processability theory (Pienemann, 1998) and the learner's categorial analysis of Chinese adjectives and stative verbs (which cross-categorize) in the acquisition process. An examination of 3 longitudinal L2 data sets revealed more stative verbs (Vstatives) than adjectives in the learners' L2 Chinese. Furthermore, there appeared to be a correlation between the number of adjectives in the L2 samples and the developmental schedule of - de(ADJ). The reasons for the findings were explored through the processing procedures required for the structures in which the adjective and the Vstative occur and the impact they had on learners' categorial analysis of adjectives and Vstatives in L2 Chinese. [source] | ||||||||||||||||