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Whole System (whole + system)
Selected AbstractsThe Change Handbook: The Definitive Resource on Today's Best Methods for Engaging Whole Systems (2nd edition)PERSONNEL PSYCHOLOGY, Issue 3 2007Article first published online: 4 SEP 200 No abstract is available for this article. [source] A kaleidoscope as a cyberworld and its animation: linear architecture and modeling based on an incrementally modular abstraction hierarchyCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2006Tosiyasu L. Kunii Abstract An incrementally modular abstraction hierarchy is known to effectively linearize cyberworlds and virtual worlds, which are combinatorially exploding and hardly managed. It climbs down from general level to specific model preserving the higher level modules as invariants. It not only prevents the combinatorial explosion but also benefits the reuse, development, testing and validation of cyberworld resources. By applying this incrementally modular abstraction hierarchy to a kaleidoscope animation, its architecture and modeling is also specified in this paper as a typical case of cyberworlds. In particular, a homotopy lifting property and a homotopy extension property, which satisfy a duality relation, are also described to show how a kaleidoscope world is systematically created top-down from the whole system and bottom-up from the components. Copyright © 2006 John Wiley & Sons, Ltd. [source] Numerical investigation of heat transport and fluid flow during the seeding process of oxide Czochralski crystal growth Part 1: non-rotating seedCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2007M. H. Tavakoli Abstract For the seeding process of oxide Czochralski crystal growth, the flow and temperature field of the system as well as the seed-melt interface shape have been studied numerically using the finite element method. The configuration usually used initially in a real Czochralski crystal growth process consists of a crucible, active afterheater, induction coil with two parts, insulation, melt, gas and non-rotating seed crystal. At first the volumetric distribution of heat inside the metal crucible and afterheater inducted by the RF coil was calculated. Using this heat source the fluid flow and temperature field were determined in the whole system. We have considered two cases with respect to the seed position: (1) before and (2) after seed touch with the melt. It was observed that in the case of no seed rotation (,seed = 0), the flow pattern in the bulk melt consists of a single circulation of a slow moving fluid. In the gas domain, there are different types of flow motion related to different positions of the seed crystal. In the case of touched seed, the seed-melt interface has a deep conic shape towards the melt. It was shown that an active afterheater and its location with respect to the crucible, influences markedly the temperature and flow field of the gas phase in the system and partly in the melt. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Soil,pile,structure interaction under SH wave excitationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2003K. K. Koo Abstract A continuum model for the interaction analysis of a fully coupled soil,pile,structure system under seismic excitation is presented in this paper. Only horizontal shaking induced by harmonic SH waves is considered so that the soil,pile,structure system is under anti-plane deformation. The soil mass, pile and superstructure were all considered as elastic with hysteretic damping, while geometrically both pile and structures were simplified as a beam model. Buildings of various heights in Hong Kong designed to resist wind load were analysed using the present model. It was discovered that the acceleration of the piled-structures at ground level can, in general, be larger than that of a free-field shaking of the soil site, depending on the excitation frequency. For typical piled-structures in Hong Kong, the amplification factor of shaking at the ground level does not show simple trends with the number of storeys of the superstructure, the thickness and the stiffness of soil, and the stiffness of the superstructure if number of storeys is fixed. The effect of pile stiffness on the amplification factor of shaking is, however, insignificant. Thus, simply increasing the pile size or the superstructure stiffness does not necessarily improve the seismic resistance of the soil,pile,structure system; on the contrary, it may lead to excessive amplification of shaking for the whole system. Copyright © 2003 John Wiley & Sons, Ltd. [source] A numerical,analytical combined method for vibration of a beam excited by a moving flexible bodyINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 10 2007Huajiang Ouyang Abstract The vibration of a beam excited by a moving simple oscillator has been extensively studied. However, the vibration of a beam excited by an elastic body with conformal contact has attracted much less attention. This is the subject of the present paper. The established model is more complicated but has a much wider range of applications than the moving-oscillator model. Because the moving body is flexible, the moving loads at the contact interface are not known a priori and must be determined together with the dynamics of the whole system. In this paper, the equation of motion of the beam and the moving body are established separately using a numerical,analytical combined approach. It is found from the numerical results of the simulated example that the vibrations of the moving body and the beam excited by the moving body are significantly influenced by the travelling speed. At very low or very high speeds the dynamic effect is small and the beam deforms to take the shape of its static deflection. Vibrations tend to be greater in the intermediate speed range and the total moving force at the interface of the beam and the moving body can be compressive and tensile. Copyright © 2007 John Wiley & Sons, Ltd. [source] A confrontation of 1D and 2D RKDG numerical simulation of transitional flow at open-channel junctionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2009R. Ghostine Abstract In this study, a comparison between the 1D and 2D numerical simulation of transitional flow in open-channel networks is presented and completely described allowing for a full comprehension of the modeling water flow. For flow in an open-channel network, mutual effects exist among the channel branches joining at a junction. Therefore, for the 1D study, the whole system (branches and junction) cannot be treated individually. The 1D Saint Venant equations calculating the flow in the branches are then supplemented by various equations used at the junction: a discharge flow conservation equation between the branches arriving and leaving the junction, and a momentum or energy conservation equation. The disadvantages of the 1D study are that the equations used at the junction are of empirical nature due to certain parameters given by experimental results and moreover they often present a reduced field of validity. On the contrary, for the 2D study, the entire network is considered as a single unit and the flow in all the branches and junctions is solved simultaneously. Therefore, we simply apply the 2D Saint Venant equations, which are solved by a second-order Runge,Kutta discontinuous Galerkin method. Finally, the experimental results obtained by Hager are used to validate and to compare the two approaches 1D and 2D. Copyright © 2009 John Wiley & Sons, Ltd. [source] A coupled lattice BGK model for the Boussinesq equations,INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2002Zhaoli Guo Abstract In this paper, a thermal lattice BGK model is developed for the Boussinesq incompressible fluids. The basic idea is to solve the velocity field and the temperature field using two independent lattice BGK equations, respectively, and then combine them into one coupled model for the whole system. The porous plate problem and the two-dimensional natural convection flow in a square cavity with Pr=0.71 and various of Rayleigh numbers are simulated using the model. The numerical results are found to be in good agreement with the analytical solutions or those of previous studies. Copyright © 2002 John Wiley & Sons, Ltd. [source] Restrictions to the use of cleanrooms for packaging pasteurised milkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2010GEORGIANA S B AIRES The study evaluated the effect of packaging pasteurised milk inside an ISO Class 8 cleanroom and an external Class 7 antechamber. Chemical, microbiological and sensory analyses of three trials did not show evidence of improvements in the product shelf life, although the total airborne particle and the viable airborne counts were considerable higher outside the cleanroom than inside it. Post-pasteurisation contaminations inherent to the equipments should be considered in futures studies. Therefore, the use of cleanroom technology is an operational alternative to be taken into consideration, provided that the characteristics of the whole system is compatible with the high standards of the clean air. [source] Energy and exergy analysis of a double absorption heat transformer operating with water/lithium bromideINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2009H. Martínez Abstract In the present study, the first and second law of thermodynamics have been used to analyze in detail the performance of a double absorption (lift) heat transformer operating with the water,lithium bromide mixture. A mathematical model was developed to estimate the coefficient of performance (COP), the exergy coefficient of performance (ECOP), the total exergy destruction in the system (,TD) and the exergy destruction (,D) in each one of the main components, as a function of the system temperatures, the efficiency of the economizer (EFEC), the gross temperature lift and flow ratio (FR). The results showed that the generator is the component with the highest irreversibilities or exergy destruction contributing to about 40% of the total exergy destruction in the whole system, reason why this component should be carefully designed and optimized. The results also showed that the COP and ECOP increase with increase in the generator, the evaporator and the absorber,evaporator temperatures and decrease with the absorber and condenser temperatures. Finally, it was observed that the COP and ECOP are very dependent of the FR and the economizer efficiency (EFEC) values. Also the optimum operating region of the analyzed system is shown in the present study. Copyright © 2009 John Wiley & Sons, Ltd. [source] Optimum matching parameters of an MPPT unit used for a PVG-powered water pumping system for maximum power transferINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2006Mehmet Akbaba Abstract Photovoltaic generator (PVG)-powered water pumping has the potential to bring potable water to millions of people in developing countries. However, due to the high initial cost of PVG units, sophisticated load matching is required between the water pumping system and PVG, in order to be able to extract maximum available power from an available PVG unit at all solar radiation levels. This requires an intermediate circuitry between the PVG unit and the motor driving the water pump, which is usually termed as maximum power point trackers (MPPT). This present paper therefore investigates the optimum matching parameters of a power conditioning circuit, which is composed of a double step-up dc,dc converter (DSUC). This MPTT circuit is used for interfacing a permanent magnet (PM) motor-driven water pumping system to a PVG for extracting maximum available power from PVG, hence maximizing the energy utilization efficiency and price,performance ratio of the whole system. It is shown that two key parameters of the DSUC, which are the duty cycle and chopping frequency, are dominating the performance of the whole system, and they are interrelated and load dependent. Therefore, optimum values of these parameters need to be determined. An example system is provided in which a complete modelling is presented in time domain and through numerical experiments it is demonstrated how the optimum values of these two key matching parameters can be determined for a given system. The MPPT circuit used in this investigation is suitable for optimum matching of all types of loads to PVG units, provided that an optimum frequency,duty cycle pair is determined for the choppers in DSUC for every 5% bands of solar radiation between 20 and 100%. Copyright © 2005 John Wiley & Sons, Ltd. [source] Experimental investigation of the performance of a solar-assisted ground-source heat pump system for greenhouse heatingINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2005Onder Ozgener Abstract The main objective of the present study is to investigate the performance characteristics of a solar-assisted ground-source heat pump system (SAGSHPS) for greenhouse heating with a 50 m vertical 1¼ in nominal diameter U-bend ground heat exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir (568 degree days cooling, base: 22°C, 1226 degree days heating, base: 18°C), Turkey. Based upon the measurements made in the heating mode, the heat extraction rate from the soil is found to be, on average, 54.08 Wm,1 of bore depth, while the required borehole length in meter per kW of heating capacity is obtained as 12.57. The entering water temperature to the unit ranges from 8.2 to 16.2°C, with an average value of 9.1°C. The greenhouse air is at a maximum day temperature of 25°C and night temperature of 14°C with a relative humidity of 40%. The heating coefficient of performance of the heat pump (COPHP) is about 2.13 at the end of a cloudy day, while it is about 2.84 at the end of sunny day and fluctuates between these values in other times. The COP values for the whole system are also obtained to be 5,15% lower than COPHP. Copyright © 2004 John Wiley & Sons, Ltd. [source] Life cycle assessment of a PPV plant applied to an existing SUW management systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2003Francesco Di Maria Abstract The huge amount of wastes produced by modern and developed countries involves important aspects of economical, social and technical fields and also of the environment. For this reason, different technologies have been proposed for trying to reduce the impact of waste management and disposal. Generally waste management system consists of different steps like selective collection, recycling and reuse operation, energy recovery from waste and landfilling. A new technology proposed for thermal waste treatment is the plasma pyrolysis vetrification (PPV). This system seems to have interesting perspective due to the possibility of thermal treatment of dangerous slag or waste producing inactivate vetrified substances that can be landfilled or used as building materials with no impact on the environment. In this study, the effect of the application of a PPV plant on an existing waste management system was evaluated with a life cycle assessment (LCA) analysis. All the activities connected to the existing system have been carefully analysed by collecting a large quantity of experimental data. Some assumptions have been made, in particular, on the PPV plant performance. LCA analysis results illustrate how the environmental benefits arising from the adoption of the new technology, concerns only few aspects of the whole system. Copyright © 2003 John Wiley & Sons, Ltd. [source] Robust tracking control for a class of MIMO nonlinear systems with measurable output feedbackINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2008Ya-Jun Pan Abstract This paper proposes a robust output feedback controller for a class of nonlinear systems to track a desired trajectory. Our main goal is to ensure the global input-to-state stability (ISS) property of the tracking error nonlinear dynamics with respect to the unknown structural system uncertainties and external disturbances. Our approach consists of constructing a nonlinear observer to reconstruct the unavailable states, and then designing a discontinuous controller using a back-stepping like design procedure to ensure the ISS property. The observer design is realized through state transformation and there is only one parameter to be determined. Through solving a Hamilton,Jacoby inequality, the nonlinear control law for the first subsystem specifies a nonlinear switching surface. By virtue of nonlinear control for the first subsystem, the resulting sliding manifold in the sliding phase possesses the desired ISS property and to certain extent the optimality. Associated with the new switching surface, the sliding mode control is applied to the second subsystem to accomplish the tracking task. As a result, the tracking error is bounded and the ISS property of the whole system can be ensured while the internal stability is also achieved. Finally, an example is presented to show the effectiveness of the proposed scheme. Copyright © 2007 John Wiley & Sons, Ltd. [source] Nondestructive characterization of ferrofluids by wide-angle synchrotron light diffraction: crystalline structure and size distribution of colloidal nanoparticlesJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2008Alexei Vorobiev The combination of magnetic and nonmagnetic interactions between the colloidal particles in ferrofluids results in various local inter-particle correlations that, in turn, change the macroscopic properties of the whole system. Therefore, characterization of the particle ensemble is a crucial point, allowing optimization of a ferrofluid for a particular application. Here it is shown how the crystal structure of the particles can be easily obtained in a fast synchrotron light diffraction experiment without any special treatment of the ferrofluid sample. Moreover, from the same diffraction patterns, such important parameters as particle mean size and dispersion are retrieved; these are compared with the corresponding parameters obtained from electron microscopy data. A particular problem of magnetite,maghemite transformation in nanoparticles stabilized by the surfactant shell is pointed out. [source] Large-scale molecular dynamics simulations of HLA-A*0201 complexed with a tumor-specific antigenic peptide: Can the ,3 and ,2m domains be neglected?JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2004Shunzhou Wan Abstract Large-scale massively parallel molecular dynamics (MD) simulations of the human class I major histocompatibility complex (MHC) protein HLA-A*0201 bound to a decameric tumor-specific antigenic peptide GVYDGREHTV were performed using a scalable MD code on high-performance computing platforms. Such computational capabilities put us in reach of simulations of various scales and complexities. The supercomputing resources available for this study allow us to compare directly differences in the behavior of very large molecular models; in this case, the entire extracellular portion of the peptide,MHC complex vs. the isolated peptide binding domain. Comparison of the results from the partial and the whole system simulations indicates that the peptide is less tightly bound in the partial system than in the whole system. From a detailed study of conformations, solvent-accessible surface area, the nature of the water network structure, and the binding energies, we conclude that, when considering the conformation of the ,1,,2 domain, the ,3 and ,2m domains cannot be neglected. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1803,1813, 2004 [source] Specific force field parameters determination for the hybrid ab initio QM/MM LSCF methodJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2002Nicolas Ferré Abstract The pure quantum mechanics method, called Local Self-Consistent Field (LSCF), that allows to optimize a wave function within the constraint that some predefined spinorbitals are kept frozen, is discussed. These spinorbitals can be of any shape, and their occupation numbers can be 0 or 1. Any post-Hartree,Fock method, based on the restricted or unrestricted Hartree,Fock Slater determinant, and Kohn,Sham-based DFT method are available. The LSCF method is easily applied to hybrid quantum mechanics/molecular mechanics (QM/MM) procedure where the quantum and the classical parts are covalently bonded. The complete methodology of our hybrid QM/MM scheme is detailed for studies of macromolecular systems. Not only the energy but also the gradients are derived; thus, the full geometry optimization of the whole system is feasible. We show that only specific force field parameters are needed for a correct description of the molecule, they are given for some general chemical bonds. A careful analysis of the errors induced by the use of molecular mechanics in hybrid computation show that a general procedure can be derived to obtain accurate results at low computation effort. The methodology is applied to the structure determination of the crambin protein and to Menshutkin reactions between primary amines and chloromethane. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 610,624, 2002 [source] Dynamic modeling, stability, and energy efficiency of a quadrupedal walking machineJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2001Ben Sheng Lin In the past, the dynamics of walking machines was studied based on very simple or simplified leg structures. A more complete dynamic model is essential for the further development of a practical walking machine. In this paper, the dynamic model of a realistic quadrupedal walking machine is derived for simulation and real-time control purposes. The walker has four cylindrical pantograph legs, and the whole system consists of twenty-nine links. The walking gait is wave gait with at least three feet on the ground at any time. Significant efforts have been made to improve the computational efficiency of the inverse dynamics, and the required CPU time is less than 10 ms on an IBM 3090. The derived dynamic model is then applied to study two practical issues of walking: dynamic stability and mechanical efficiency of different legs and gaits. Simulation results show clear advantages of one leg type over another, and of some walking strategies in terms of adjusting velocities, strokes, and duty factors for greater efficiency. © 2001 John Wiley & Sons, Inc. [source] Older persons' experiences of whole systems: the impact of health and social care organizational structuresJOURNAL OF NURSING MANAGEMENT, Issue 2 2008BRENDAN McCORMACK BSc (Hons) Nursing, DPhil (Oxon) Aim(s), An in-depth case study of whole systems working. Background, This paper reports on the second part of a two-part study exploring whole systems working. Part 1 of the study focused on an in-depth review of the literature pertaining to continuity of care and service integration. The second part, reported here, focused on an in-depth case study of one whole system. Evaluation, Informed by the findings of part 1 of the study, data collection methods included in-depth interviews, real-time tracking of 18 older people, focus groups and consensus conferencing. Different data sets were analysed individually and synthesized using matrices derived from the literature review findings. Key issue(s), Key themes from data synthesis include: (1) access to the most appropriate services; (2) service fragmentation; (3) continuity of care; and (4) routinized care. Conclusion(s), The four themes of the case study reflect the need to address issues of demarcation of professional responsibilities, complicated channels of communication, information flows, assessment and reassessment in whole systems working. Implications for nursing management, The impact of disempowering relationships on actual continuity of care and perceptions of quality among service users and providers. Lessons need to be learnt from specialist services and applied to service delivery in general. [source] Comparing flow-reversal and inner recirculation reactors: Experiments and simulationsAICHE JOURNAL, Issue 7 2003Moshe Ben-Tullilah The operation of reactors with flow reversal operate similar to a reactor with internal recirculation, which the feed enters through one (say, inner) reactor and then turns around and flows out through (the outer) another, when the heat-transfer coefficient between the tubes is large. In this study, we compare the behavior of a packed-bed reactor operating in flow-reversal or internal-recirculation modes, using ethylene oxidation on Pt/Al2O3 as a model reaction. The reactor was built from two concentric tubes (with 28.5 and 42.5 mm in diameter), both packed with a 20 cm catalytic bed and 10 cm inert beds (of alumina-pellets) on each side. An adjustable opening between the tubes allowed for an internal recycle mode and the whole system could be operated with periodic flow reversal. The reactor can be employed then either as a simple once-through bed or as a bed with flow reversal in the inner tube or as bed with internal recirculation flowing from the inner to outer tube, or in the opposite direction, as well as an internal-recirculation reactor with flow reversal. Due to heat losses, the latter two modes were inferior to the others. The experiments, backed by simulations using a homogeneous model with independently determined parameters, showed that the technically-simpler inner-outer internal-recycle reactor operated better at low flow rates, than that with flow reversal, but the conclusion is reversed at high flow rates. The domain where the internal-recirculation reactor is superior depends on the heat-transfer coefficient between the streams. By lowering the feed concentration, the extinction point was determined for each mode highlighting again the conclusions drawn above that inner-recirculation operation may be superior to flow reversal at low flow rates. Simulations revealed also the existence of solutions with stationary fronts or oscillatory fronts. [source] Best practice from admission to discharge in acute inpatient care: considerations and standards from a whole system perspectiveJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 6 2005A. JONES phd bn (hons) rmn Effective mental health care and promotion involves numerous agencies and individuals. Hence, practice development for people with acute mental health needs requires a systemic (or whole system) perspective. Whilst a policy imperative, this is unfamiliar practice for many health and social care workers. In a previous paper published within this journal, the authors argued that admission to acute inpatient care may sometimes be occasioned by the need to contain worker anxiety within the whole system, rather than being clinically justified or necessary. In this paper the authors seek to follow up this premise with proposals for purposeful admission and standards to assure the quality throughout the patient journey, into and out of acute inpatient wards. [source] Robust full-duplex ROF systemMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010D. H. Thomas Abstract We present a simple and robust full-duplex radio-over-fiber (ROF) system using two laser sources with efficient laser frequency stability control enlarging the reliability of the whole system with automatic operation. Error-free operation was obtained at 52 and 155 Mb/s. The system was successfully tested for ASI/SDI-coded digital TV transmission at 270 Mb/s. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1009,1013, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25120 [source] The extraordinary radio galaxy MRC B1221,423: probing deeper at radio and optical wavelengthsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2010Helen M. Johnston ABSTRACT We present optical spectra and high-resolution multiwavelength radio observations of the compact steep-spectrum radio source MRC B1221,423 (z= 0.1706). MRC B1221,423 is a very young (,105 yr), powerful radio source which is undergoing a tidal interaction with a companion galaxy. We find strong evidence of interaction between the active galactic nucleus (AGN) and its environment. The radio morphology is highly distorted, showing a dramatic interaction between the radio jet and the host galaxy, with the jet being turned almost back on itself. H i observations show strong absorption against the nucleus at an infall velocity of ,250 km s,1 compared to the stellar velocity, as well as a second, broader component which may represent gas falling into the nucleus. Optical spectra show that star formation is taking place across the whole system. Broad optical emission lines in the nucleus show evidence of outflow. Our observations confirm that MRC B1221,423 is a young radio source in a gas-rich nuclear environment, and that there was a time delay of a few times 100 Myr between the onset of star formation and the triggering of the AGN. [source] A finite element-based approach for whole-system simulation of packaging systems for their improved design and operationPACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2009Ben James Hicks Abstract The introduction of legislation to minimize packaging waste requires consumer goods manufacturers to use lighter-weight materials and increase the use of recycled materials. This is demanding that machinery manufacturers provide highly flexible machines and tooling capable of handling these materials and new package designs. However, the ability of manufacturers to achieve this is all but prevented by a lack of fundamental understanding of machine,material interactions and an ability to generate such understanding. One way to overcome this is to use advanced simulation tools to represent the whole system including machine, process, materials and product. A finite element-based simulation has been created to represent the in-process behaviour of a packing system. The simulation focuses on the critical transition between flattened and erected states of a carton. In order to successfully simulate such a complex process, there are a number of major challenges concerning the representation of packaging materials and their properties, changing material behaviour during processing, machinery simulation and process modelling (simulating the interfacial interactions that take place during processing). The application of the whole-system simulation for the purposes of improved design and operation are discussed with respect to four activities: design and set-up of tooling, determination of optimal process settings, specification of material properties and the design of the pack. In all cases, a strong correlation was observed between the theoretical results and those obtained practically, thereby enabling quantitative understanding and quantitative rules to be generated. Copyright © 2009 John Wiley & Sons, Ltd. [source] Understanding quantum dots: overheating of the LO-phonon modesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2007K. Král Abstract Longitudinal optical phonons have been used recently to explain the electronic energy relaxation in quantum dots. In this theory they served as a reservoir, on which the electron executes multiple scattering acts. Rather naturally such a phonon subsystem is expected to be passive, namely, in a long-time limit of development the whole system should be able to achieve such a stationary state in which statistical distributions of both subsystems, electron and phonons, do not change in time. Here we remind briefly that the recent approach to the relaxation theory in quantum dots displays a non-passivity of such a reservoir. We remind briefly the method of a partial elimination of this phonon overheating effect by using the Lang-Firsov transformation. We apply the modified relaxation theory to the electronic relaxation at low electronic densities in quantum dot systems and come to conclusions about the role of e-LO scattering mechanism in these situations. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Vibration of the soil caused by a vehicle moving over the randomly uneven surface of a slab trackPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003H. Grundmann Univ.-Prof. A vehicle which passes an uneven surface of a slab track causes vibrations of the whole system: the vehicle, the slab track and the subsoil. For a given random unevenness ,w of the slab track surface, covariances of the soil surface motion are calculated. [source] Transient rate matrix determination for the complex systemQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 1 2001Isa S. Qamber Abstract This paper presents new techniques dealing with the reliability of complex systems. A power station reliability assessment model is used to illustrate the approach. Before calculating the state transient probabilities for the overall electrical power plant, the failure and repair rates of each generating unit are needed. These two coefficients can form a transition rate matrix, which represents each generator. To form the overall system a special technique is required. In the present study the direct-differentiation and the Kronecker algebra methods are used to form the overall transition rate matrix, which represents the whole system. Forming the overall system is the first part (major part) of the current study. The second part is to calculate the state transient probabilities, following the Adams method. Two electric power plants from the State of Bahrain are analysed as examples. Copyright © 2001 John Wiley & Sons, Ltd. [source] The Aachen MiniHLM,A Miniaturized Heart-Lung Machine for Neonates With an Integrated Rotary Blood PumpARTIFICIAL ORGANS, Issue 9 2010Jutta Arens Abstract The operation of congenital heart defects in neonates often requires the use of heart-lung machines (HLMs) to provide perfusion and oxygenation. This is prevalently followed by serious complications inter alia caused by hemodilution and extrinsic blood contact surfaces. Thus, one goal of developing a HLM for neonates is the reduction of priming volume and contact surface. The currently available systems offer reasonable priming volumes for oxygenators, reservoirs, etc. However, the necessary tubing system contains the highest volumes within the whole system. This is due to the use of roller pumps; hence, the resulting placement of the complete HLM is between 1 and 2 m away from the operating table due to connective tubing between the components. Therefore, we pursued a novel approach for a miniaturized HLM (MiniHLM) by integrating all major system components in one single device. In particular, the MiniHLM is a HLM with the rotary blood pump centrically integrated into the oxygenator and a heat exchanger integrated into the cardiotomy reservoir which is directly connected to the pump inlet. Thus, tubing is only necessary between the patient and MiniHLM. A total priming volume of 102 mL (including arterial filter and a/v line) could be achieved. To validate the overall concept and the specific design we conducted several in vitro and in vivo test series. All tests confirm the novel concept of the MiniHLM. Its low priming volume and blood contact surface may significantly reduce known complications related to cardiopulmonary bypass in neonates (e.g., inflammatory reaction and capillary leak syndrome). [source] European Solar Telescope: Progress statusASTRONOMISCHE NACHRICHTEN, Issue 6 2010M. Collados Abstract In this paper, the present status of the development of the design of the European Solar Telescope is described. The telescope is devised to have the best possible angular resolution and polarimetric performance, maximizing the throughput of the whole system. To that aim, adaptive optics and multi-conjugate adaptive optics are integrated in the optical path. The system will have the possibility to correct for the diurnal variation of the distance to the turbulence layers, by using several deformable mirrors, conjugated at different heights. The present optical design of the telescope distributes the optical elements along the optical path in such a way that the instrumental polarization induced by the telescope is minimized and independent of the solar elevation and azimuth. This property represents a large advantage for polarimetric measurements. The ensemble of instruments that are planned is also presented (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High resolution in z -direction: The simulation of disc-bulge-halo galaxies using the particle-mesh code SUPERBOXASTRONOMISCHE NACHRICHTEN, Issue 9-10 2008R. Bien Abstract SUPERBOX is known as a very efficient particle-mesh code with highly-resolving sub-grids. Nevertheless, the height of a typical galactic disc is small compared to the size of the whole system. Consequently, the numerical resolution in z direction, i. e. vertically with respect to the plane of the disc, remains poor. Here, we present a new version of SUPERBOX that allows for a considerably higher resolution along z. The improved code is applied to investigate disc heating by the in-fall of a galaxy satellite. We describe the improvement and communicate our results. As an important application we discuss the disruption of a dwarf galaxy within a disc-bulge-halo galaxy that consists of some 106 particles. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Promoted H2 Generation from NH3BH3 Thermal Dehydrogenation Catalyzed by Metal,Organic Framework Based CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2010Dr. Yaoqi Li Abstract The application of ammonium borane (AB) as a hydrogen storage material is limited by the sluggish kinetics of H2 release. Two catalysts based on metal,organic frameworks (MOFs) have been prepared either by applying MOF as precursors or by the in situ reduction method. In the release of H2 from AB, the high H2 content of the whole system, the remarkably lower reaction onset temperature, the significantly increased H2 release rates at ,90,°C, and the decreased reaction exothermicity have all been achieved with only 1.0,mol,% MOF-based catalyst. Moreover, the clear catalytic diversity of three catalysts has been observed and discussed. The in situ synthesized Ni0 sites and the MOF supports in the catalysts were proven to show significant and different effects to promote the catalytic activities. With MOF-based catalysts, both the enhanced kinetics and the high H2 capacity of the AB system present great advantages for future use. [source] | ||||||||||||||||||||||