Home About us Contact
|
Home About us Contact | ||
|
|
||
Single Process (single + process)
Selected AbstractsNanostructured Organic,Inorganic Composite Materials by Twin Polymerization of Hybrid MonomersADVANCED MATERIALS, Issue 20 2009Stefan Spange Abstract Forming two structurally different but associated polymer structures in a single step is a possible route for the production of nanostructured materials. By means of twin polymerization of specially constructed monomers consisting of two different covalently bonded building blocks (hybrid monomers), this route is realized. What is important is that two different macromolecular structures are formed from one monomer in a single process. The two polymers formed can be linear, branched, or cross-linked structures. The molecular composition of the hybrid monomer defines the degree of cross-linking of the corresponding macromolecular structures that is theoretically possible. [source] Use of thermodynamic functions for expressing some relevant aspects of sustainabilityINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2005Simone Bastianoni Abstract Sustainability is a key concept for our future and the role of thermodynamics in its assessment is fundamental. The use of energy and matter must be considered not only from a microscopic viewpoint (the use of a single fuel or material, or the presence of a single pollutant) but also by means of holistic approaches able to synthesize all the characteristics of a single process. Exergy is a suitable function for this purpose. The exergy concept can also be applied to natural systems and to systems at the interface between natural and artificial ones. In this context also emergy can express very helpful indications. Four different efficiency indices are here examined to better understand different aspects of the sustainability of processes and systems. An application to two similar agricultural systems (wine production in Italy) shows how these indices work in real case studies. Copyright © 2005 John Wiley & Sons, Ltd. [source] Bilinear modelling of batch processes.JOURNAL OF CHEMOMETRICS, Issue 5 2008Part I: theoretical discussion Abstract When studying the principal component analysis (PCA) or partial least squares (PLS) modelling of batch process data, one realizes that there is a wide range of approaches. In many cases, new modelling approaches are presented just because they work properly for a particular application, for example, on-line monitoring and a given number of processes. A clear understanding of why these approaches perform successfully and which are the advantages and disadvantages in front of the others is seldom supplied. Why does modelling after batch-wise unfolding capture changing dynamics? What are the consequences of variable-wise unfolding? Is there any best unfolding method? When should several models for a single process be used? In this paper, it is shown how these and other related questions can be answered by properly analyzing the dynamic covariance structures of the various approaches. Copyright © 2008 John Wiley & Sons, Ltd. [source] Autodiffusion: a novel method for emitter formation in crystalline silicon thin-film solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2007A. Wolf Abstract The in situ formation of an emitter in monocrystalline silicon thin-film solar cells by solid-state diffusion of dopants from the growth substrate during epitaxy is demonstrated. This approach, that we denote autodiffusion, combines the epitaxy and the diffusion into one single process. Layer-transfer with porous silicon (PSI process) is used to fabricate n-type silicon thin-film solar cells. The cells feature a boron emitter on the cell rear side that is formed by autodiffusion. The sheet resistance of this autodiffused emitter is 330,,/,. An independently confirmed conversion efficiency of (14·5,±,0·4)% with a high short circuit current density of (33·3,±,0·8) mA/cm2 is achieved for a 2,×,2,cm2 large cell with a thickness of (24,±,1) µm. Transferred n-type silicon thin films made from the same run as the cells show effective carrier lifetimes exceeding 13,µs. From these samples a bulk diffusion length L,>,111,µm is deduced. Amorphous silicon is used to passivate the rear surface of these samples after the layer-transfer resulting in a surface recombination velocity lower than 38,cm/s. Copyright © 2006 John Wiley & Sons, Ltd. [source] Finding and solving problems in software new product developmentTHE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 2 2002Willow A. Sheremata New product development is notoriously difficult, and software new product development particularly so. Although a great deal of research has investigated new product development, projects developing new software products continue to have problems meeting their goals. In fact, one line of research proposes new product development is difficult because it must solve an ongoing stream of complex problems. I integrate this line of research with two others to develop a conceptual framework of new product development as a process of finding and solving problems. From this framework, I develop four hypotheses that predict the probability projects developing new products will attain their development schedule and product quality goals. More specifically, I hypothesize that projects that generate access to, and integrate, large quantities of creative ideas, in-depth knowledge, and accurate information, should increase their probability of attaining schedule and product quality goals. Projects developing new products should both generate and integrate this "knowledge" to solve the problems that stand between them and their goals. However, how projects find problems also matters. Projects that search to identify problems earlier, rather than later, should also increase their probability of meeting schedule and product quality goals. To test these hypotheses I gathered data on 33 projects that tried to develop new software products from 23 firms, through interviews and questionnaires. Results from regression analyses support three out of four hypotheses. The projects that had high levels of both knowledge generation and integration had a significantly higher probability of attaining their product quality goals, but not their schedule goals. In contrast, projects that merely searched to find problems had a higher probability of attaining both goals. Moreover, projects that not only generated and integrated knowledge to solve problems, but also searched to find them, had the highest probability of attaining their product quality goals. This study illustrates the usefulness of modeling new product development as a bundle of problems to be found and solved. These results suggest that projects that combine practices to implement high levels of both knowledge generation and integration,not just one or the other,increase their chances of meeting product quality goals. This in turn suggests that focus on any single process or practice may be misplaced. Moreover, proactive search for problems may increase projects' chances of meeting both schedule and product quality goals. In fact, search for problems was highly significant in this study, which suggests the way projects identify problems deserves further study. Although these prescriptions are preliminary, this study suggests they can help projects,and their managers,embody their visions in products and deliver those products to market. et. [source] Shrinkage drift parameter estimation for multi-factor Ornstein,Uhlenbeck processesAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2010Sévérien Nkurunziza Abstract We consider some inference problems concerning the drift parameters of multi-factors Vasicek model (or multivariate Ornstein,Uhlebeck process). For example, in modeling for interest rates, the Vasicek model asserts that the term structure of interest rate is not just a single process, but rather a superposition of several analogous processes. This motivates us to develop an improved estimation theory for the drift parameters when homogeneity of several parameters may hold. However, the information regarding the equality of these parameters may be imprecise. In this context, we consider Stein-rule (or shrinkage) estimators that allow us to improve on the performance of the classical maximum likelihood estimator (MLE). Under an asymptotic distributional quadratic risk criterion, their relative dominance is explored and assessed. We illustrate the suggested methods by analyzing interbank interest rates of three European countries. Further, a simulation study illustrates the behavior of the suggested method for observation periods of small and moderate lengths of time. Our analytical and simulation results demonstrate that shrinkage estimators (SEs) provide excellent estimation accuracy and outperform the MLE uniformly. An over-ridding theme of this paper is that the SEs provide powerful extensions of their classical counterparts. Copyright © 2009 John Wiley & Sons, Ltd. [source] Feedback quality adjustment with Bayesian state-space modelsAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2007K. TriantafyllopoulosArticle first published online: 4 DEC 200 Abstract In this paper we develop a Bayesian procedure for feedback adjustment and control of a single process. We replace the usual exponentially weighted moving average (EWMA) predictor by a predictor of a local level model. The novelty of this approach is that the noise variance ratio (NVR) of the local level model is assumed to change stochastically over time. A multiplicative time series model is used to model the evolution of the NVR and a Bayesian algorithm is developed giving the posterior and predictive distributions for both the process and the NVR. The posterior distribution of the NVR allows the modeller to judge better and evaluate the performance of the model. The proposed algorithm is semi-conjugate in the sense that it involves conjugate gamma/beta distributions as well as one step of simulation. The algorithm is fast and is found to outperform the EWMA and other methods. An example considering real data from the microelectronic industry illustrates the proposed methodology. Copyright © 2006 John Wiley & Sons, Ltd. [source] Encapsulation and Sustained Release of Curcumin using Superparamagnetic Silica ReservoirsCHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2009Fun Chin Abstract For controlled release and targeted delivery of curcumin in an aqueous medium a method of encapsulating curcumin and magnetic nanoparticles inside porous silica matrix has been developed. Curcumin and superparamagnetic nanoparticles are loaded inside porous silica in a single process. The graphic shows the TEM image of microtomed sample of Fe3O4 particles surrounded by a silica matrix. [source] An Extremely Simple Dibenzopentalene Synthesis from 2-Bromo-1-ethynylbenzenes Using Nickel(0) Complexes: Construction of Its Derivatives with Various FunctionalitiesCHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2009Takeshi Kawase Prof. Abstract Nice and easy: A very simple synthesis for dibenzopentalenes, which starts from 1-bromo-2-ethynylbenzenes, has been developed. It uses Ni0 complexes (see scheme), from which a relatively stable NiII complex as an important intermediate has been isolated. Dibenzopentalenes with various functional groups can be prepared by the procedure, and their electronic properties are consistent with theoretical calculations. An extremely simple dibenzopentalene synthesis from readily available 2-bromo-1-ethynylbenzenes using a nickel(0) complex is described. Although the yields are moderate, the formation of three CC bonds in a single process and the high availability of the starting materials are important advantages of this reaction. The corresponding aryl,nickel(II) complex as an important intermediate was isolated as relatively stable crystals, and the structure was confirmed by X-ray crystallographic analysis. The high stability of this complex should play a key role in this reaction. The reaction is applicable to the preparation of dibenzopentalenes bearing various functional groups. Their electronic properties are consistent with theoretical calculations. The cyclic voltammograms of these compounds reveal highly amphoteric redox properties. In particular, the electron-donating property of a tetramethoxy derivative is greater than that of oligothiophenes and dibenzodithiophenes and almost comparable to that of pentacene. [source] The relation of personality types to physiological, behavioural, and cognitive processesEUROPEAN JOURNAL OF PERSONALITY, Issue 5 2005Daniel Hart Three personality types, labeled resilient, over-controlled, and under-controlled, were identified through cluster analysis of classroom observations of 63 children, and used to understand biological, cognitive, and behavioural processes that influence academic achievement and aggression. Resilient children were found to be high in trait cortisol and high in academic achievement. Under-controlled and over-controlled children showed the greatest change in cortisol levels under stress, low levels of academic achievement, and attributed hostility to others in ambiguous situations. Under-controlled children also exhibited high levels of externalizing behaviour in the classroom. The findings suggest that the single processes or traits assessed in this study do not mediate the associations of personality types to academic achievement and behaviour. The implications of the findings for the personality type construct and for personality processes are discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] | |||||||||||||