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New Design (new + design)
Selected AbstractsNew Design of a Ceramic Filter for Diesel Emission Control ApplicationsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2005Aleksander J. Pyzik Diesel particulate filters (DPF) made from an advanced ceramic material (ACM) based on mullite have demonstrated high filtration efficiency, low-pressure drop, high-temperature handling capability, and excellent mechanical integrity at a porosity of 60% or higher. Due to the ability to control microstructure, total porosity, and particle size distribution, Dow's acicular mullite can be tailored to meet requirements for deep bed filtration and fine particles emission control. In addition, the ACM DPF is suitable for catalyzed applications and it can retain its performance with a broad range of catalysts and over a wide range of catalyst loadings. This study describes a material selected for a DPF design that meets current diesel particulate emission control requirements as well as a four-way NOx control system. [source] How Much Policy Governance Is Required for It to Be Policy Governance?BOARD LEADERSHIP: POLICY GOVERNANCE IN ACTION, Issue 83 2006Article first published online: 14 MAR 200 Board Leadership is pleased to reproduce here a very slightly modified excerpt from the brand-new third edition of John Carver's Boards That Make a Difference: A New Design for Leadership in Nonprofit and Public Organizations (Jossey-Bass, 2006). The excerpt from Chapter 12, titled "But Does It Work?" appears between a response to various model criticisms and a discussion of research on governance effectiveness. [source] Compact multiband slotted antenna for wireless communication applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2009Yi-Chieh Lee Abstract New design of a compact antenna with slotted structure for multioperating bands of wireless communication systems is presented. By using compact configuration and slot designs on printed circuit board, the proposed antenna has the multiband measured operations for covering the 2.4-GHz WLAN (2.4,2.484 GHz), the WiMAX (IEEE 802.16e in the Taiwan: 2.5,2.69/3.5,3.65 GHz), and the 5-GHz WLAN (5.15,5.35/5.725,5.825 GHz) bands. Several properties of the proposed compact antenna for multiband operation such as impedance bandwidth, radiation pattern, and measured gain have been numerically and experimentally investigated. © 2008 Wiley Periodcals, Inc. Microwave Opt Technol Lett 51: 502,503, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24094 [source] New design of actuator using shear piezoelectricity of a chiral polymer, and prototype devicePOLYMER INTERNATIONAL, Issue 3 2010Michiya Sawano Abstract Chiral polymers have been known to exhibit small shear piezoelectricity for about fifty years. However, recently, we reported that poly(L -lactic acid) treated with supercritical carbon dioxide (sc-PLLA), which is a type of chiral polymer, exhibits much higher shear piezoelectricity than other chiral polymers. On the other hand, we found an important difference between motion due to shear piezoelectricity and that due to tensile piezoelectricity in piezoelectric materials through computer simulations. On the basis of these results, we fabricated a new type of electrically controlled tweezers constructed from a pair of sc-PLLA sheets with shear piezoelectricity. In general, when conventional tweezers open to the left and right, the trajectory of their motion becomes fanlike at the center of the connection (one end of the tweezers). In the new tweezers, the two small sheets making up the tweezers open parallel to each other, without the motion of parts near the connection. Moreover, a prototype ,finger' system using sc-PLLA sheets to realize complex motion in which the finger curled upon stretching of the sc-PLLA sheets was manufactured as a trial device. Using the prototype finger system, we demonstrated the firm grasping of a sample, but the sample could not be removed from a vessel. Thus, sc-PLLA increases the likelihood of realizing a device with highly operational pick-up in a very small region by using the shear piezoelectricity of a chiral polymer. Copyright © 2010 Society of Chemical Industry [source] Polarized light out-coupling from lightguides for LCDsTHE CHEMICAL RECORD, Issue 2 2005C. M. van Heesch Abstract New designs of lightguide systems, which emit linear polarized light with a high efficiency for transmissive and transflective LCD applications, are presented. These systems are equipped with nano- and/or micro-structured films or coatings, which emit highly collimated or diffuse linearly polarized light with a high efficiency. The films are based on polarization-selective scattering, reflection, or diffraction of light and their properties can be tuned to a large extent dependent on their envisioned application. For instance, edge-lit lightguide systems are discussed, which combine a range of desirable features such as a high transparency in direct view, a direct emission of light at normal angles to the plane of the lightguide, and a purely unidirectional out-coupling of light towards the LCD-side. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 59,69; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20034 [source] Response simulation and seismic assessment of highway overcrossingsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2010Anastasios Kotsoglou Abstract Interaction of bridge structures with the adjacent embankment fills and pile foundations is generally responsible for response modification of the system to strong ground excitations, to a degree that depends on soil compliance, support conditions, and soil mass mobilized in dynamic response. This paper presents a general modeling and assessment procedure specifically targeted for simulation of the dynamic response of short bridges such as highway overcrossings, where the embankment soil,structure interaction is the most prevalent. From previous studies it has been shown that in this type of interaction, seismic displacement demands are magnified in the critical bridge components such as the central piers. This issue is of particular relevance not only in new design but also in the assessment of the existing infrastructure. Among a wide range of issues relevant to soil,structure interaction, typical highway overcrossings that have flexible abutments supported on earth embankments were investigated extensively in the paper. Simulation procedures are proposed for consideration of bridge-embankment interaction effects in practical analysis of these structures for estimation of their seismic performance. Results are extrapolated after extensive parametric studies and are used to extract ready-to-use, general, and parameterized capacity curves for a wide range of possible material properties and geometric characteristics of the bridge-embankment assembly. Using two instrumented highway overpasses as benchmark examples, the capacity curves estimated using the proposed practical procedures are correlated successfully with the results of explicit incremental dynamic analysis, verifying the applicability of the simple tools developed herein, in seismic assessment of existing short bridges. Copyright © 2009 John Wiley & Sons, Ltd. [source] Evaluation of a by-catch reduction device for glass eel fishing trapsFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2009M. A. LOPEZ Abstract, The effectiveness of a new design of glass eel, Anguilla anguilla (L.), fishing trap was tested in the Ebro River delta fishery (Eastern Mediterranean, Spain). The modified fishing trap incorporated a by-catch reduction device (BRD) to increase trap selectivity and minimise by-catch of non-targeted fish, without affecting glass eel captures. The BRD is inexpensive and easy to implement, consisting of a cylinder covered with a rigid square-mesh of 2.0,2.4 mm knot-to-knot, which is easily fitted to the fishing trap entrance. Testing of the BRD was made by paired comparisons between captures of targeted and non-targeted fish species from both conventional and BRD-modified traps. The use of a BRD in the glass eel traps resulted in a 68.9% reduction in the number of captured non-targeted fish specimens, while it did not reduce glass eel yields. The BRD implementation was fully effective for all species and individuals with sizes >40 mm total length, with the exception of the black-striped pipefish, Syngnathus abaster Risso. These results support the implementation of the BRD in glass eel fisheries along the Eastern coast of the Iberian Peninsula where these fishing traps are used. [source] Design spaces, measures and metrics for evaluating quality of time operators and consequences leading to improved algorithms by design,illustration to structural dynamicsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 14 2005X. Zhou Abstract For the first time, for time discretized operators, we describe and articulate the importance and notion of design spaces and algorithmic measures that not only can provide new avenues for improved algorithms by design, but also can distinguish in general, the quality of computational algorithms for time-dependent problems; the particular emphasis is on structural dynamics applications for the purpose of illustration and demonstration of the basic concepts (the underlying concepts can be extended to other disciplines as well). For further developments in time discretized operators and/or for evaluating existing methods, from the established measures for computational algorithms, the conclusion that the most effective (in the sense of convergence, namely, the stability and accuracy, and complexity, namely, the algorithmic formulation and algorithmic structure) computational algorithm should appear in a certain algorithmic structure of the design space amongst comparable algorithms is drawn. With this conclusion, and also with the notion of providing new avenues leading to improved algorithms by design, as an illustration, a novel computational algorithm which departs from the traditional paradigm (in the sense of LMS methods with which we are mostly familiar with and widely used in commercial software) is particularly designed into the perspective design space representation of comparable algorithms, and is termed here as the forward displacement non-linearly explicit L-stable (FDEL) algorithm which is unconditionally consistent and does not require non-linear iterations within each time step. From the established measures for comparable algorithms, simply for illustration purposes, the resulting design of the FDEL formulation is then compared with the commonly advocated explicit central difference method and the implicit Newmark average acceleration method (alternately, the same conclusion holds true against controllable numerically dissipative algorithms) which pertain to the class of linear multi-step (LMS) methods for assessing both linear and non-linear dynamic cases. The conclusions that the proposed new design of the FDEL algorithm which is a direct consequence of the present notion of design spaces and measures, is the most effective algorithm to-date to our knowledge in comparison to the class of second-order accurate algorithms pertaining to LMS methods for routine and general non-linear dynamic situations is finally drawn through rigorous numerical experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source] Using virtual topologies to manage inter-domain QoS in next-generation networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2010Ricardo B. Freitas Recently, several computer fields have turned to virtualization as a way to simplify complex problems. In this context, the Virtual Topology Service (VTS) was created to manage the advertisement and acquisition of virtual topologies (abstractions of the network status of a domain) and their use in inter-domain resource reservation to provide end-to-end quality of service (QoS). As an effort to create new network architectures which could attend current requirements like mobility and context-aware applications and support autonomous, heterogeneous and mobile domains next-generation networks (NGNs) emerged, with Ambient Networks (AN) as one of its instances. With an ever increasing multitude of online applications, end-to-end QoS has become increasingly important, especially for media and real-time uses. In this context, in order to better manage inter-domain QoS in these new networks, better coping with mobile nodes and domains, this work presents a new design and implementation of the VTS, adapted to the AN environment. The new VTS stores resource reservation information to enable the reuse of these reservations when re-establishing QoS after a node/domain movement. This implementation was tested on a real NGN prototype and showed considerable time saving when compared to QoS re-establishment without reusing the reservations. Copyright © 2009 John Wiley & Sons, Ltd. [source] A three-dimensional current cell (TCC) for the TLM methodINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 2 2001F. Mauro Faccioni This paper presents a new design for a three-dimensional cell for the TLM method, and its application in the resonator analysis. The new proposed cell is based on ,, - type' transmission line, and it uses incident and reflected currents. A condensed scattering matrix is developed. The computational results are compared with the analytical results and with TLM-SCN (symmetrical condensed node) computational results. Copyright © 2001 John Wiley & Sons, Ltd. [source] Modeling and measurements of novel monolithic inductors and transformersINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2005Aly H. Aly Abstract This paper presents the analysis, modeling, and measurements of a novel configuration of spiral inductors and transformers to enhance the figure of merits. The present configuration utilizes a Z -shaped multilayer metalization to increase the Q of the monolithic inductors, and increase K without sacrificing the Q of the monolithic transformers. A simple two-port lumped-circuit model derived from inductor S -parameters is used to illustrate the potential of the new design. Several on-chip transformers have been fabricated using the Motorola 0.18-micron copper process. The experimental data shows good agreement with predicted data obtained using the HFSS software simulator. A noticeable increase of mutual coupling and Q is achieved. The transformer can be optimized to achieve high Q or high K or both. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source] Position-dependent disturbance rejection using spatial-based adaptive feedback linearization repetitive controlINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2009Cheng-Lun Chen Abstract In this paper, we propose a new design of spatial-based repetitive control for a class of rotary motion systems operating at variable speeds. The open-loop system in spatial domain is obtained by reformulating a nonlinear time-invariant system with respect to angular displacement. A two-degree-of-freedom control structure (comprising two control modules) is then proposed to robustly stabilize the open-loop system and improve the tracking performance. The first control module applies adaptive feedback linearization with projected parametric update and concentrates on robust stabilization of the closed-loop system. The second control module introduces a spatial-based repetitive controller cascaded with a loop-shaping filter, which not only further reduces the tracking error, but also improves parametric adaptation. The overall control system is robust to model uncertainties of the system and capable of rejecting position-dependent disturbances under varying process speeds. Stability proof for the overall system is given. A design example with simulation is provided to demonstrate the applicability of the proposed design. Copyright © 2008 John Wiley & Sons, Ltd. [source] Incorporation of a new design of backing seat and anvil in a Merrill,Bassett diamond anvil cellJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2008Stephen A. Moggach A modification to the Merrill,Bassett miniature diamond anvil cell is reported here, with the inclusion of tungsten carbide backing seats with Boehler,Almax-cut diamonds to replace the previously used beryllium seats and (typically) modified brilliant-cut anvils. This has led to the removal of troublesome beryllium powder lines from diffraction images, while maintaining the pressure range and opening angle of the original design. [source] Wideband spurious suppression of dual-mode band-pass filter using defected cascaded resonatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Hung-Wei Wu Abstract This article presents a new design of wideband spurious suppression of dual-mode band-pass filter (BPF) using defected cascaded resonators (DCRs). The pattern of the DCRs is similar with that of the conventional low-pass stepped impedance resonator, whereas it is etched in the ground. It is verified that adding DCRs in planar BPF can effectively provide a very wideband range for spurious suppression. The dual-mode BPF is designed at center frequency (f0) of 5.2 GHz, and has a very wideband spurious suppression below 30 dB as far as over 5f0 when using the DCRs. The measured results have a good agreement with the EM simulated results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1694,1697, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25332 [source] Design of a broadband dual circularly polarized square slot antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008G. Zhao Abstract In this article, a new design of a broadband dual circularly polarized square slot antenna loaded with metallic strips is presented. The proposed dual circular polarization (CP) radiations are achieved by loading the square slot with a T-shaped strip and two microstrip T-junctions. The designed antenna is implemented and measured. The experimental results show that the proposed antenna has good dual CP characteristics and a 3-dB axial ratio bandwidth is more than 19%. The isolation between two ports is better than 20 dB within the CP operating band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2639,2642, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23741 [source] Improved EBG-loaded waveguide low-pass filterMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2008Yi-ming Tang Abstract A new design of electromagnetic band gap (EBG) waveguide low-pass filter (LPF) loaded with double-array is described to improve the stopband characteristics. Broader gapband width, about 2-GHz broader than the traditional filters, greater stopband attenuation, and moderate passband insert loss (0.5 dB) can be obtained. Theoretical and measured results are in good agreement. The filter can be employed for the out-of-passband clutter rejection of traditional filters. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2090,2093, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23608 [source] Radio as a Learning TechnologyNEW DIRECTIONS FOR ADULT & CONTINUING EDUCATION, Issue 88 2000May Maskow A recent initiative in educational radio successfully used a new design,a doculecture,to attract credit learners and interested members of the public. [source] Negative permeability around 630 nm in nanofabricated vertical meander metamaterialsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2007Heinz Schweizer Abstract We demonstrate a new design of a 3-dimensional meander structure that exhibits negative permeability with a broad bandwidth between 550 nm and 665 nm. The structural design allows for full coupling of the magnetic field component at all angles of incidence. We compare our structure with other metamaterial structures with respect to the series capacitance contributions of the different metamaterials. The investigation of optical metamaterials is carried out combining transmission line analysis with numerical simulations of Maxwell's equations. The analysis is demonstrated for typical split ring structures and the novel 3D meander metamaterial structures. Comparing the resulting scattering parameter spectra as well as the retrieved effective material parameters, we find that transmission line description remains valid for metamaterials at optical frequencies. We find in addition that the longitudinal capacitance is the decisive parameter to achieve negative permeability with a broad bandwidth at optical frequencies. For experimental verification we manufactured split-ring resonator structures and meander metamaterial structures with linewidths down to 30 nm, element sizes down to 100 nm, and periods between 200 nm and 350 nm. For meander metamaterial structures a permeability value of ,1 was achieved within a bandwidth of 50 nm centered at 630 nm. The largest absolute value of ,4.5 was achieved at 650 nm. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Plasma-Assisted Atomic Layer Deposition of Al2O3 at Room TemperaturePLASMA PROCESSES AND POLYMERS, Issue S1 2009Tommi O. Kääriäinen Abstract A new design of plasma source has been used for the plasma-assisted atomic layer deposition (PA-ALD) of Al2O3 films at room temperature. In this PA-ALD reactor the plasma is generated by capacitive coupling directly in the deposition chamber adjacent to the substrate but can be separated from it by a grid to reduce the ion bombardment while maintaining the flow of radicals directly to the substrate surface. During the ALD cycle a mixture of nitrogen and argon was introduced into the reactor to act as a purge gas between precursor pulses and to facilitate the generation of a plasma during the plasma cycle. Sequential exposures of TMA and excited O2 precursors were used to deposit Al2O3 films on Si(100) substrates. A plasma discharge was activated during the oxygen gas pulse to form radicals in the reactor space. The experiments showed that the growth rate of the film increased with increasing plasma power and with increasing O2 pulse length before saturating at higher power and longer O2 pulse length. The growth rate saturated at the level of 1.78 Å·cycle,1. EDS analysis showed that the films were oxygen rich and had carbon as an impurity. This can be explained by the presence of bonds between hydrocarbons from the unreacted TMA precursor and excess oxygen in the film. ATR-FTIR spectroscopy measurements indicated a change in growth mechanism when the distance between the location of the radical generation and the substrate was varied. A similar effect was observed with the use of different plasma power levels. [source] Preparation and characterization of polyurethane,gold nanocomposites prepared using encapsulated gold nanoparticlesPOLYMER INTERNATIONAL, Issue 7 2010Chao-Ching Chang Abstract Gold nanoparticles (GNPs) have been widely studied due to their unique properties. Although many research groups have developed the synthesis of GNPs using various polymers as stabilizing or reducing agents, the effects of GNPs on the structures and properties of polymer matrices have been less reported. We propose a new design for the preparation of polyurethane,gold (PU,Au) nanocomposites. 11-Mercapto-1-undecanol-coated GNPs acted as the chain extenders and reacted with isocyanates to form covalent bonds between PU and GNPs. PU,Au nanocomposites were successfully synthesized, and the effects of multifunctional GNPs on the structures, morphology and properties of poly(ester urethane) were investigated. Scanning electron microscopy images suggested the GNPs can be dispersed uniformly in the PU matrix. Maltese-cross of spherical crystals was observed in the PU,Au nanocomposites, and the size of the crystals decreased with an increase in gold content. As the gold content increased, the thermal decomposition temperature and the temperature of the maximum decomposition rate increased. The glass transition temperature, crystal melting temperature and melting enthalpy of the soft segment also increased progressively. The results showed that multifunctional GNPs concentrated hard segments and resulted in an increase of heterogeneous nucleation, phase separation and elasticity. Copyright © 2010 Society of Chemical Industry [source] Step-reset options: Design and valuationTHE JOURNAL OF FUTURES MARKETS, Issue 2 2002L. Paul Hsueh This study proposes a new design of reset options in which the option's exercise price adjusts gradually, based on the amount of time the underlying spent beyond prespecified reset levels. Relative to standard reset options, a step-reset design offers several desirable properties. First of all, it demands a lower option premium but preserves the same desirable reset attribute that appeals to market investors. Second, it overcomes the disturbing problem of delta jump as exhibited in standard reset option, and thus greatly reduces the difficulties in risk management for reset option sellers who hedge dynamically. Moreover, the step-reset feature makes the option more robust against short-term price movements of the underlying and removes the pressure of price manipulation often associated with standard reset options. To value this innovative option product, we develop a tree-based valuation algorithm in this study. Specifically, we parameterize the trinomial tree model to correctly account for the discrete nature of reset monitoring. The use of lattice model gives us the flexibility to price step-reset options with American exercise right. Finally, to accommodate the path-dependent exercise price, we introduce a state-to-state recursive pricing procedure to properly capture the path-dependent step-reset effect and enhance computational efficiency. © 2002 John Wiley & Sons, Inc. Jrl Fut Mark 22:155,171, 2002 [source] Chattering reduction of sliding mode control by low-pass filtering the control signalASIAN JOURNAL OF CONTROL, Issue 3 2010Ming-Lei Tseng Abstract The conventional approach to reducing control signal chattering in sliding mode control is to use the boundary layer design. However, when there is high-level measurement noise, the boundary layer design becomes ineffective in chattering reduction. This paper, therefore, proposes a new design for chattering reduction by low-pass filtering the control signal. The new design is non-trivial since it requires estimation of the sliding variable via a disturbance estimator. The new sliding mode control has the same performance as the boundary layer design in noise-free environments, and outperforms the boundary layer design in noisy environments. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Principal Stratification Designs to Estimate Input Data Missing Due to DeathBIOMETRICS, Issue 3 2007Constantine E. Frangakis Summary We consider studies of cohorts of individuals after a critical event, such as an injury, with the following characteristics. First, the studies are designed to measure "input" variables, which describe the period before the critical event, and to characterize the distribution of the input variables in the cohort. Second, the studies are designed to measure "output" variables, primarily mortality after the critical event, and to characterize the predictive (conditional) distribution of mortality given the input variables in the cohort. Such studies often possess the complication that the input data are missing for those who die shortly after the critical event because the data collection takes place after the event. Standard methods of dealing with the missing inputs, such as imputation or weighting methods based on an assumption of ignorable missingness, are known to be generally invalid when the missingness of inputs is nonignorable, that is, when the distribution of the inputs is different between those who die and those who live. To address this issue, we propose a novel design that obtains and uses information on an additional key variable,a treatment or externally controlled variable, which if set at its "effective" level, could have prevented the death of those who died. We show that the new design can be used to draw valid inferences for the marginal distribution of inputs in the entire cohort, and for the conditional distribution of mortality given the inputs, also in the entire cohort, even under nonignorable missingness. The crucial framework that we use is principal stratification based on the potential outcomes, here mortality under both levels of treatment. We also show using illustrative preliminary injury data that our approach can reveal results that are more reasonable than the results of standard methods, in relatively dramatic ways. Thus, our approach suggests that the routine collection of data on variables that could be used as possible treatments in such studies of inputs and mortality should become common. [source] 2141: Fitting of challenging corneas with a special design of rigid gas permeable (RGP) lensACTA OPHTHALMOLOGICA, Issue 2010W ABOU SAMRA Purpose To study the safety and efficacy of a new design of RGP lens namely Rose K irregular cornea (IC) in management of corneas with high degree of irregular astigmatism. Methods The study was made in 66 eyes of 40 patients with irregular astigmatism. The selection criterion was to obtain a sample population with irregular astigmatism that was unlikely to be corrected with spectacles or conventional contact lens. A complete ophthalmologic exploration which included topography was made. All eyes were fitted with Rose K IC after measuring precisely lens parameters according to a special trial set of this design.Refraction, visual acuity before and after fitting,maximum wearing time, contact lens related problems and patient satisfaction were analyzed. Results The studied eyes included eyes with high degree of irregular astigmatism due to keratoconus in 42 eyes (63.6%),corneal injuries in 6 eyes (9.1%), PMD in 12 eyes (18.2%), and post Lasik ectasia in 6 eyes (9.1%). After fitting of the eyes with the RGP lens, there was a significant improvement in the visual acuity (VA)in all fitted eyes. The mean VA improved from 0.16±0.25 to 0.85± 0.13(p<0.001).Study of spherical and astigmatic errors showed also a highly significant improvement. The mean spherical error was -4.6 ± 2.4 and improved to 0.50 ± 0.20 after final fitting (p<0.001). The mean astigmatic error of studied eyes was -6.2 ± 2.3 while after fitting was -0.75±0.32(p<0.001).Statistical analysis of the subjective responses indicated a strong acceptance of the lens by all subjects. Conclusion Rose K IC proved to be effective in correcting high degree of corneal astigmatism caused by a variable number of challenging corneal conditions with high visual performance and good patient comfortability. [source] Current density mapping approach for design of clinical magnetic resonance imaging magnetsCONCEPTS IN MAGNETIC RESONANCE, Issue 3 2002Stuart Crozier Abstract Novel current density mapping (CDM) schemes are developed for the design of new actively shielded, clinical magnetic resonance imaging (MRI) magnets. This is an extended inverse method in which the entire potential solution space for the superconductors has been considered, rather than single current density layers. The solution provides an insight into the required superconducting coil pattern for a desired magnet configuration. This information is then used as an initial set of parameters for the magnet structure, and a previously developed hybrid numerical optimization technique is used to obtain the final geometry of the magnet. The CDM scheme is applied to the design of compact symmetric, asymmetric, and open architecture 1.0,1.5 T MRI magnet systems of novel geometry and utility. A new symmetric 1.0-T system that is just 1 m in length with a full 50-cm diameter of the active, or sensitive, volume (DSV) is detailed, as well as an asymmetric system in which a 50-cm DSV begins just 14 cm from the end of the coil structure. Finally a 1.0-T open magnet system with a full 50-cm DSV is presented. These new designs provide clinically useful homogeneous regions and have appropriately restricted stray fields but, in some of the designs, the DSV is much closer to the end of the magnet system than in conventional designs. These new designs have the potential to reduce patient claustrophobia and improve physician access to patients undergoing scans. © 2002 Wiley Periodicals, Inc. Concepts in Magnetic Resonance (Magn Reson Engineering) 15: 208,215, 2002 [source] Optimizing Service Attributes: The Seller's Utility Problem,DECISION SCIENCES, Issue 2 2001Fred F. Easton Abstract Service designers predict market share and sales for their new designs by estimating consumer utilities. The service's technical features (for example, overnight parcel delivery), its price, and the nature of consumer interactions with the service delivery system influence those utilities. Price and the service's technical features are usually quite objective and readily ascertained by the consumer. However, consumer perceptions about their interactions with the service delivery system are usually far more subjective. Furthermore, service designers can only hope to influence those perceptions indirectly through their decisions about nonlinear processes such as employee recruiting, training, and scheduling policies. Like the service's technical features, these process choices affect quality perceptions, market share, revenues, costs, and profits. We propose a heuristic for the NP-hard service design problem that integrates realistic service delivery cost models with conjoint analysis. The resulting seller's utility function links expected profits to the intensity of a service's influential attributes and also reveals an ideal setting or level for each service attribute. In tests with simulated service design problems, our proposed configurations compare quite favorably with the designs suggested by other normative service design heuristics. [source] Recent advances in capillary electrophoresis and capillary electrochromatography of peptidesELECTROPHORESIS, Issue 22-23 2003Václav Ka Abstract An overview of the recent developments in the applications of high-performance capillary electromigration methods, namely zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography, to analysis, preparation, and physicochemical characterization of peptides is presented. New approaches to the theoretical description and experimental verification of the electromigration behavior of peptides and the methodological aspects of capillary electroseparations of peptides, such as rational selection of separation conditions, sample treatment, and suppression of adsorption, are discussed, and new developments in individual separation modes and new designs of detection systems applied to peptide separations are shown. Several types of applications of capillary electromigration methods to peptide analysis are presented: quality control and purity tests, determination in biomatrices, monitoring of physical and chemical changes and enzymatic conversions, amino acid and sequence analysis, and peptide mapping. The examples of micropreparative peptide separations are given and capabilities of capillary electromigration techniques to provide important physicochemical characteristics of peptides are demonstrated. [source] Design, analysis, and synthesis of generalized single step single solve and optimal algorithms for structural dynamicsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2004X. Zhou Abstract The primary objectives of the present exposition are to: (i) provide a generalized unified mathematical framework and setting leading to the unique design of computational algorithms for structural dynamic problems encompassing the broad scope of linear multi-step (LMS) methods and within the limitation of the Dahlquist barrier theorem (Reference [3], G. Dahlquist, BIT 1963; 3: 27), and also leading to new designs of numerically dissipative methods with optimal algorithmic attributes that cannot be obtained employing existing frameworks in the literature, (ii) provide a meaningful characterization of various numerical dissipative/non-dissipative time integration algorithms both new and existing in the literature based on the overshoot behavior of algorithms leading to the notion of algorithms by design, (iii) provide design guidelines on selection of algorithms for structural dynamic analysis within the scope of LMS methods. For structural dynamics problems, first the so-called linear multi-step methods (LMS) are proven to be spectrally identical to a newly developed family of generalized single step single solve (GSSSS) algorithms. The design, synthesis and analysis of the unified framework of computational algorithms based on the overshooting behavior, and additional algorithmic properties such as second-order accuracy, and unconditional stability with numerical dissipative features yields three sub-classes of practical computational algorithms: (i) zero-order displacement and velocity overshoot (U0-V0) algorithms; (ii) zero-order displacement and first-order velocity overshoot (U0-V1) algorithms; and (iii) first-order displacement and zero-order velocity overshoot (U1-V0) algorithms (the remainder involving high-orders of overshooting behavior are not considered to be competitive from practical considerations). Within each sub-class of algorithms, further distinction is made between the design leading to optimal numerical dissipative and dispersive algorithms, the continuous acceleration algorithms and the discontinuous acceleration algorithms that are subsets, and correspond to the designed placement of the spurious root at the low-frequency limit or the high-frequency limit, respectively. The conclusion and design guidelines demonstrating that the U0-V1 algorithms are only suitable for given initial velocity problems, the U1-V0 algorithms are only suitable for given initial displacement problems, and the U0-V0 algorithms are ideal for either or both cases of given initial displacement and initial velocity problems are finally drawn. For the first time, the design leading to optimal algorithms in the context of a generalized single step single solve framework and within the limitation of the Dahlquist barrier that maintains second-order accuracy and unconditional stability with/without numerically dissipative features is described for structural dynamics computations; thereby, providing closure to the class of LMS methods. Copyright © 2003 John Wiley & Sons, Ltd. [source] Development of synthetic double helical polymers and oligomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2009Yoshio Furusho Abstract There is growing interest in the design and synthesis of artificial helical polymers and oligomers, in connection with biological importance as well as development of novel chiral materials. Since the discovery of the helical structure of isotactic polypropylene, a significant advancement has been achieved for synthetic polymers and oligomers with a single helical conformation for about half a century. In contrast, the chemistry of double helical counterparts is still premature. This short review highlights the recent advances in the synthesis, structures, and functions of double helical polymers and oligomers, featuring an important role of supramolecular chemistry in the design and synthesis of double helices. Although the artificial double helices reported to date are still limited in number, recent advancement of supramolecular chemistry provides plenty of structural motifs for new designs. Therefore, artificial double helices hold great promise as a new class of compounds. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5195,5207, 2009 [source] Robust sequential designs for nonlinear regressionTHE CANADIAN JOURNAL OF STATISTICS, Issue 4 2002Sanjoy Sinha Abstract The authors introduce the formal notion of an approximately specified nonlinear regression model and investigate sequential design methodologies when the fitted model is possibly of an incorrect parametric form. They present small-sample simulation studies which indicate that their new designs can be very successful, relative to some common competitors, in reducing mean squared error due to model misspecifi-cation and to heteroscedastic variation. Their simulations also suggest that standard normal-theory inference procedures remain approximately valid under the sequential sampling schemes. The methods are illustrated both by simulation and in an example using data from an experiment described in the chemical engineering literature. Les auteurs définissent formellement le concept de modéle de régression non linéaire approxima-tif et proposentdes plans d'expérience séquentiels pour les situations o4uG la forme paramétrique du modéle ajusté est inexacte. Ils présentent une étude de simulation qui montre que, pour de petits échantillons, leurs nouveaux plans sont largement préférables aux plans usuels en terme de réduction de I'erreur quadratique moyenne associée à rinadéquation du modéle et à l'hétéroscédasticité. Leurs simulations montrent aussi que les procédures d'inférence classiques associées au paradigme normal restent valables, à peu de choses prés, pour ces plans expéimentaux se'quentiels. La methodologie proposde est illustrée par voie de simulation et au moyen d'une application concréte tirée de la pratique du génie chimique. [source] | ||||||||||||||||||||||||||||