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Design Considerations (design + consideration)

Distribution by Scientific Domains

Engineering	37%
Chemistry	13%
Medical Sciences	10%
Physics and Astronomy	6%
Information Science and Computing	6%
5 Other Domains	28%

Selected Abstracts

Design Considerations for Research on Analytical Procedures

INTERNATIONAL JOURNAL OF AUDITING, Issue 3 2001
Stephen K. Asare
This article discusses research design considerations for conducting behavioral research on auditors' performance of analytical procedures (APs). With the trend in practice towards increasing reliance on APs, it is essential that auditors are proficient in completing such tests. Therefore, research to understand and improve auditors' performance of APs is important. Once an unexpected fluctuation is identified, APs involve three phases: generation of plausible hypotheses (likely causes); gathering evidence to examine plausible hypotheses; and identification of the most likely cause followed by appropriate follow-up actions. Although prior research has focused on these phases in isolation, they are, in fact, interrelated. Important research design issues and trade-offs for each of the phases of APs are discussed. For instance, in examining hypothesis generation there are choices as to the amount and nature of case background information, number of ratios or accounts to explain; ex-post evaluation of the quality of the hypothesis set; and instructions on number of causes that account for the fluctuation. Significant considerations are identified for making informed decisions among design choices. [source]

Design Considerations for Plate and Frame Ultrafiltration Modules by Computational Fluid Dynamics Analysis,

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2006
Mauro M. Dal-Cin
Abstract Pressure and flow maldistributions were studied in a full-scale industrial plate and frame ultrafiltration module, operating in a Z flow pattern, for the recovery of used motor oils. Solutions were obtained using (1) a three-dimensional solution of the Navier-Stokes equation using computational fluid dynamics and (2) Bernoulli's equation and a momentum balance in one dimension. Fluid decelerations and accelerations generated pressure increases and decreases in the distributor and collector, respectively, biasing the flow distribution to the last channel. Several modifications to the original design were evaluated; the most effective was larger distributor and collector diameters, which greatly improved the uniformity of the flow distribution and transmembrane pressure, and reduced the overall pressure drop in a bank. A variable diameter distributor and collector module was designed using the 1-D model. Flow distribution was significantly improved but also yielded an undesirable overall higher pressure drop and a pressure maldistribution in the bank. The maldistribution of the main inlet manifold to the distributors in the first bank was strongly dependent on the module design. The flow distribution across the width of a channel became uniform within a short distance, essentially eliminating the need to consider this design aspect any further. Flows at the bank outlets, and hence inlets of the following bank, showed uniform lateral distribution in all cases, suggesting that future modelling work can be limited to a fraction of the module width, based on symmetry, in order to gain computational efficiency. On a étudié les mauvaises distributions de pression et d'écoulement dans un module d'ultrafiltration à plateaux et à cadres à l'échelle industrielle, fonctionnant dans un schéma d'écoulement en Z, pour la récupération des huiles de moteurs usées. Des solutions ont été obtenues avec (1) une solution tridimensionnelle de l'équation de Navier-Stokes utilisant la mécanique des fluides par ordinateur, et (2) l'équation de Bernoulli et un bilan de quantité de mouvement unidimensionnel. Les décélérations et accélérations de fluide entraînent des augmentations et diminutions de pression dans le distributeur et le collecteur, respectivement, ce qui fausse la distribution d'écoulement dans le dernier canal. On a évalué plusieurs modifications du concept original; la plus efficace sont des diamètres de distributeur et de collecteur plus larges, qui permettent d'améliorer grandement l'uniformité de la distribution d'écoulement et la pression transmembranaire, et qui réduisent la perte de charge globale dans une batterie. Un module de distributeur et de collecteur de diamètres variables a été conçu au moyen du modèle 1D. La distribution d'écoulement est significativement améliorée mais cause une perte de charge globale plus grande indésirable et une mauvaise distribution de pression dans la batterie. La mauvaise distribution du manifold d'entrée principal vers les distributeurs dans la première batterie est fortement dépendante de la conception du module. La distribution d'écoulement dans toute la largeur d'un canal devient uniforme sur une courte distance, éliminant essentiellement le besoin d'approfondir cet aspect de la conception. L'écoulement en sortie de batteries et donc à l'entrée des batteries suivantes montre une distribution latérale uniforme dans tous les cas, ce qui suggère que le travail de modélisation futur peut se limiter à une fraction de la largeur du module, pour des raisons de symétrie, pour gagner de l'efficacité numérique. [source]

The Polder Computing Environment: a system for interactive distributed simulation

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13-15 2002
K. A. Iskra
Abstract The paper provides an overview of an experimental, Grid-like computing environment, Polder, and its components. Polder offers high-performance computing and interactive simulation facilities to computational science. It was successfully implemented on a wide-area cluster system, the Distributed ASCI Supercomputer. An important issue is an efficient management of resources, in particular multi-level scheduling and migration of tasks that use PVM or sockets. The system can be applied to interactive simulation, where a cluster is used for high-performance computations, while a dedicated immersive interactive environment (CAVE) offers visualization and user interaction. Design considerations for the construction of dynamic exploration environments using such a system are discussed, in particular the use of intelligent agents for coordination. A case study of simulatedabdominal vascular reconstruction is subsequently presented: the results of computed tomography or magnetic resonance imaging of a patient are displayed in CAVE, and a surgeon can evaluate the possible treatments by performing the surgeries virtually and analysing the resulting blood flow which is simulated using the lattice-Boltzmann method. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Organic greenroof architecture: Design considerations and system components

ENVIRONMENTAL QUALITY MANAGEMENT, Issue 1 2005
Linda S. Velazquez
First page of article [source]

The efficacy and safety of QVAR (hydrofluoroalkane-beclometasone diproprionate extrafine aerosol) in asthma (part 2): clinical experience in children

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 8 2004
C. P. Van Schayck
Summary QVAR [hydrofluoroalkane-134a beclometasone dipropionate (BDP)] produces equivalent asthma control to chlorofluorocarbon-based BDP inhalers, at approximately half the daily dose in adults, a probable consequence of the increased lung deposition of QVAR that results from its greater fine particle fraction. Recent studies have relied on the clinical experience with QVAR in adults as a basis for investigations in childhood asthma. Design considerations, such as the use of the breath-actuated AutohalerÔ delivery device and measurement of direct health benefits, account for problems of variation in inspiratory flow, handling difficulties and low airways resistance that are associated with children. QVAR appears to be well tolerated in children with no clinically relevant adverse effects on adrenal function, bone metabolism or growth at recommended doses. [source]

A digitally controlled band-switching VCO using switching inductors and capacitors in 0.18 ,m CMOS

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008
Tienyu Chang
Abstract In this article, a digitally controlled band-switching voltage controlled oscillator (VCO) is designed and fabricated using TSMC 0.18 ,m CMOS technology. Design considerations regarding the power requirement and the phase noise of the VCO are discussed. Eight bands are set by three bits, with one bit controlling switching inductors, and two bits controlling switching capacitors. The VCO covers 2.9,3.45 GHz and 3.6,4.3 GHz using varactors for continuous frequency tuning. Phase noise of the VCO stays constant around ,110 dBc/Hz at 1 MHz offset for all bands. The fabricated VCO consumes 11 mA of current with 1.8 V supply voltage and has a small size of 730 ,m × 660 ,m. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1970,1973, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23496 [source]

Internal GSM/DCS dual-band open-loop antenna for laptop application

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2007
Cheng-Hao Kuo
Abstract A novel open-loop antenna with a coupled-line gap for application as an internal laptop antenna for GSM/DCS dual-band operation is presented. Owing to the use of the coupled-line gap, the proposed antenna can operate both as a half-wavelength loop structure at 900 MHz and a one-wavelength loop structure at 1800 MHz. The antenna is easily printed on a dielectric substrate with a low cost and is then integrated to the supporting metal frame of the laptop display to achieve a compact size of 9 mm in height and 70 mm in length, making it very promising to be embedded within the casing of the laptop as an internal antenna. Design considerations of the proposed antenna are described, and experimental and simulation results of the constructed prototype are presented. Effects of the coupled-line gap on the dual-band operation of the proposed antenna are also analyzed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 680,684, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22224 [source]

A compact wide-band bandpass filter integrating SCMRC and SIRW structures

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2007
Wenquan Che
Abstract A wideband bandpass filter constructed into substrate integrated rectangular waveguide (SIRW) and incorporating spiral compact microstrip resonant cell (SCMRC) is proposed. Design considerations of these two dissimilar structures are introduced separately. A prototype was fabricated and measured. Good agreements are observed between the experimental results and the simulations. The results demonstrate a wide bandwidth of 70.7% (from 8.6 to 18 GHz), and the ripple in the entire passband is less than 2 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 195,198, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22092 [source]

Internal DTV antenna for folder-type mobile phone

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2006
Kin-Lu Wong
Abstract By using the upper and lower ground planes of a folder-type mobile phone, a novel internal shorted dipole antenna for digital television (DTV) signal reception in the 470,806-MHz band is presented. The shorted dipole antenna further comprises an internal matching circuit, which includes a chip capacitor and two narrow metal strips, for achieving improved impedance matching over the DTV band of 470,806 MHz. The proposed DTV antenna was constructed and studied. The measured return loss for the operating frequencies over the DTV band is better than 2.5:1 VSWR. In addition, good radiation characteristics are also obtained. Design considerations of the proposed internal DTV antenna are described. A parametric study of the internal matching circuit on the impedance matching of the antenna is also presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1015,1019, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21587 [source]

Design and Analysis of Arm-in-Cage Experiments: Inference for Three-State Progressive Disease Models with Common Periodic Observation Times

BIOMETRICS, Issue 2 2008
B. A. Griffin
Summary We develop statistical methods for designing and analyzing arm-in-cage experiments used to test the efficacy of insect repellents and other topical treatments. In these experiments, a controlled amount of the treatment is applied to a volunteer's forearm, which then is exposed to the insects by being placed into a special cage. Arms are not kept in the cages continuously, but rather placed there periodically for a brief period of time, during which it is noted whether an insect lands (but does not bite) or (lands and) bites. Efficacy of a repellent can be described using a progressive three-state model in which the first two states represent varying degrees of protection (no landing and landing without biting) and the third state occurs once protection is completely lost (biting). Because subjects within a treatment group follow the same cage visit schedule, transition times between states are interval censored into one of several fixed intervals. We develop an approach that uses a mixture of nonparametric and parametric techniques for estimating the parameters of interest when sojourn times are dependent. Design considerations for arm-in-cage experiments are addressed and the proposed methods are illustrated on data from a recent arm-in-cage experiment as well as simulated data. [source]

Interaction of ,-gliadin with polyanions: Design considerations for sequestrants used in supportive treatment of celiac disease

BIOPOLYMERS, Issue 5 2010
Li Liang
Abstract Copolymers of sodium 4-styrene sulfonate (SS) and hydroxyethyl methacrylate (HEMA) were investigated as sequestrants of ,-gliadin, a gluten protein, for the treatment of gluten intolerance. The interactions of ,-gliadin with poly(SS) and poly(HEMA- co -SS) with 9 and 26 mol% SS content were studied at gastric (1.2) and intestinal (6.8) pH using circular dichroism and measurements of turbidity, dynamic light scattering and zeta potential. The interactions and their influence on ,-gliadin secondary and aggregated structures depended mainly on the ratio of polymer negative and protein positive charges at pH 1.2, and on polymer SS content at polymer concentrations providing in excess of negative charges at either pH. Poly(SS) could not form complex particles with ,-gliadin in a sufficient excess of negative charges. Copolymerization with HEMA enhanced the formation of complex particles. Poly(HEMA- co -SS) with intermediate SS content was found to be the most effective sequestrant for ,-gliadin. This study provides insight into design considerations for polymer sequestrants used in the supportive treatment of celiac disease. © 2009 Wiley Periodicals, Inc. Biopolymers 93:418,428, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]

Longitudinal analysis when the experimenter does not determine when treatment ends: what is dose,response?

CLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 6 2003
Daniel J. Feaster
The most appropriate amount of psychotherapy to address a particular problem is of interest to clinicians, consumers and those responsible for funding of care. The dose,response relationship has been examined within the context of randomized clinical trials, meta-analysis as well as naturalistic studies; however, each of these approaches has limits. Many of these approaches have conceptually blurred two distinct concepts: do participants with different characteristics need different amounts of therapy and do otherwise equal participants show different outcomes when given different levels of (a particular type of) therapy? For any study design, if the experimenter does not determine the duration of therapy, then the length of therapy is said to be endogenous. This endogeneity can bias any attempt to untangle the answer to these two questions. An extension of the biasing effect of this endogeneity involves the choice of times to assess outcome; if outcome assessment depends on when therapy is terminated (rather than exogenously chosen) then estimates of the trajectory of outcome may be biased. Design considerations to minimize this effect are discussed.,Copyright © 2003 John Wiley & Sons, Ltd. [source]

Miniaturized planar ferrite junction circulator in the form of substrate-integrated waveguide

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2008
Wenquan Che
Abstract The theoretical analysis and engineering implementation of the planar substrate-integrated waveguide (SIW) ferrite junction circulator have been proposed in this article. The ferrite junction circulator is implemented in the form of SIW, taking the features of low profile, small volume and easy integration with other planar circuits. The design strategies of the device have been introduced, including the design consideration of the microstrip transition. One C-band prototype of SIW ferrite junction circulator has been fabricated and measured. The experimental results indicate the bandwidth is about 33% at ,15 dB isolation and the maximum isolation is near 40 dB. However, the insertion loss is a little big, owing to the imperfect dielectric material and fabrication inaccuracy. The SIW ferrite junction circulator and the microstrip transition are integrated into a same substrate, resulting in a very compact planar ferrite junction circulator and indicating potential applications in integrated communication and radar systems. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source]

3D Monte Carlo simulation of transport in electro-statically confined silicon nanochannels

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008
Mohamed Mohamed
Abstract This study investigates transport and electrostatic behavior of quasi 1D nanowires adopting a relatively simple planar fabrication technique. The confined conduction channel is created by etching an oxide trench, realizing a T-gate structure. Since multiple channels are normally needed to realize sufficient current drive in practical applications, the behavior of single and coupled adjacent silicon nanowires is characterized using a 3D quantum corrected Monte Carlo approach. Results indicate that a single T-gate structure provides over 27% increase in current drive compared to conventional MOSFET at a drain voltage of 1V. In addition, design consideration and recommendation is presented. Cross section of a T-gate MOSFET. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Salt tolerant membrane adsorbers for robust impurity clearance

BIOTECHNOLOGY PROGRESS, Issue 6 2009
William T. Riordan
Abstract Clearance of impurities such as viruses, host cell protein (HCP), and DNA is a critical purification design consideration for manufacture of monoclonal antibody therapeutics. Anion exchange chromatography has frequently been utilized to accomplish this goal; however, anion exchange adsorbents based on the traditional quaternary amine (Q) ligand are sensitive to salt concentration, leading to reduced clearance levels of impurities at moderate salt concentrations (50,150 mM). In this report, membrane adsorbers incorporating four alternative salt tolerant anion exchange ligands were examined for impurity clearance: agmatine, tris-2-aminoethyl amine, polyhexamethylene biguanide (PHMB), and polyethyleneimine. Each of these ligands provided greater than 5 log reduction value (LRV) for viral clearance of phage ,X174 (pI , 6.7) at pH 7.5 and phage PR772 (pI , 4) at pH 4.2 in the presence of salt. Under these same conditions, the commercial Q membrane adsorber provided no clearance (zero LRV). Clearance of host-cell protein at pH 7.5 was the most challenging test case; only PHMB maintained 1.5 LRV in 150 mM salt. The salt tolerance of PHMB was attributed to its large positive net charge through the presence of multiple biguanide groups that participated in electrostatic and hydrogen bonding interactions with the impurity molecules. On the basis of the results of this study, membrane adsorbers that incorporate salt tolerant anion exchange ligands provide a robust approach to impurity clearance during the purification of monoclonal antibodies. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]

Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildings

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2006
Stefano Pampanin
Abstract The feasibility and efficiency of a seismic retrofit solution for existing reinforced concrete frame systems, designed before the introduction of modern seismic-oriented design codes in the mid 1970s, is conceptually presented and experimentally investigated. A diagonal metallic haunch system is introduced at the beam,column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms, while inverting the hierarchy of strength within the beam,column subassemblies and forming a plastic hinge in the beam. A complete step-by-step design procedure is suggested for the proposed retrofit strategy to achieve the desired reversal of strength hierarchy. Analytical formulations of the internal force flow at the beam,column-joint level are derived for the retrofitted joints. The study is particularly focused on exterior beam,column joints, since it is recognized that they are the most vulnerable, due to their lack of a reliable joint shear transfer mechanism. Results from an experimental program carried out to validate the concept and the design procedure are also presented. The program consisted of quasi-static cyclic tests on four exterior, , scaled, beam,column joint subassemblies, typical of pre-1970 construction practice using plain round bars with end-hooks, with limited joint transverse reinforcement and detailed without capacity design considerations. The first (control specimen) emulated the as-built connection while the three others incorporated the proposed retrofitted configurations. The experimental results demonstrated the effectiveness of the proposed solution for upgrading non-seismically designed RC frames and also confirmed the applicability of the proposed design procedure and of the analytical derivations. Copyright © 2006 John Wiley & Sons, Ltd. [source]

From generative fit to generative capacity: exploring an emerging dimension of information systems design and task performance

INFORMATION SYSTEMS JOURNAL, Issue 4 2009
Michel Avital
Abstract Information systems (IS) research has been long concerned with improving task-related performance. The concept of fit is often used to explain how system design can improve performance and overall value. So far, the literature has focused mainly on performance evaluation criteria that are based on measures of task efficiency, accuracy, or productivity. However, nowadays, productivity gain is no longer the single evaluation criterion. In many instances, computer systems are expected to enhance our creativity, reveal opportunities and open new vistas of uncharted frontiers. To address this void, we introduce the concept of generativity in the context of IS design and develop two corresponding design considerations ,,generative capacity' that refers to one's ability to produce something ingenious or at least new in a particular context, and ,generative fit' that refers to the extent to which an IT artefact is conducive to evoking and enhancing that generative capacity. We offer an extended view of the concept of fit and realign the prevailing approaches to human,computer interaction design with current leading-edge applications and users' expectations. Our findings guide systems designers who aim to enhance creative work, unstructured syntheses, serendipitous discoveries, and any other form of computer-aided tasks that involve unexplored outcomes or aim to enhance our ability to go boldly where no one has gone before. In this paper, we explore the underpinnings of ,generative capacity' and argue that it should be included in the evaluation of task-related performance. Then, we briefly explore the role of fit in IS research, position ,generative fit' in that context, explain its role and impact on performance, and provide key design considerations that enhance generative fit. Finally, we demonstrate our thesis with an illustrative vignette of good generative fit, and conclude with ideas for further research. [source]

Design Considerations for Research on Analytical Procedures

Modelling and design considerations on CML gates under high-current effects

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2005
M. Alioto
Abstract In this paper, the effect of the transit time degradation of bipolar transistors on the power-delay trade-off in CML gates and their design is dealt with. A delay model which accounts for the transit time increase due to the high bias current values used in high-speed applications is derived by generalizing an approach previously proposed by the same authors (IEEE Trans. CAD 1999; 18(9):1369,1375; Model and Design of Bipolar and MOS Current,Mode Logic (CML, ECL and SCL Digital Circuits), Kluwer Academic Publisher: Dordrecht, 2005). The resulting closed-form delay expression is achieved by properly simplifying the SPICE model, and has an explicit dependence on the bias current which determines the power consumption of CML gates. Accordingly, the delay model is used to gain insight into the power-delay trade-off by considering the effect of the transit time degradation in high-speed designs. In particular, the cases where such effects can be neglected are identified, to better understand how the transit time degradation affects the performance of CML gates for current bipolar technologies. The proposed model has a simple and compact expression, thus it turns out to be suitable for pencil-and-paper evaluations, as well as fast timing analysis. Simulations of CML circuits with a 20-GHz bipolar process show that the model has a very good accuracy in a wide range of current and loading conditions. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Sample and design considerations in post-disaster mental health needs assessment tracking surveys

INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue S2 2008
Ronald C. Kessler
Abstract Although needs assessment surveys are carried out after many large natural and man-made disasters, synthesis of findings across these surveys and disaster situations about patterns and correlates of need is hampered by inconsistencies in study designs and measures. Recognizing this problem, the US Substance Abuse and Mental Health Services Administration (SAMHSA) assembled a task force in 2004 to develop a model study design and interview schedule for use in post-disaster needs assessment surveys. The US National Institute of Mental Health subsequently approved a plan to establish a center to implement post-disaster mental health needs assessment surveys in the future using an integrated series of measures and designs of the sort proposed by the SAMHSA task force. A wide range of measurement, design, and analysis issues will arise in developing this center. Given that the least widely discussed of these issues concerns study design, the current report focuses on the most important sampling and design issues proposed for this center based on our experiences with the SAMHSA task force, subsequent Katrina surveys, and earlier work in other disaster situations. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Providing multimedia communications services from high altitude platforms

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2001
D. Grace
Abstract System level design considerations for high altitude platforms operating in the mm-wave bands are examined. Propagation effects in these bands are outlined, followed by a brief introduction to different platform scenarios. Ground-based and platform-based fixed wireless access scenarios are considered, and it is shown that using a platform, a single base station can supply a much larger coverage area than a terrestrial base station. The effects on performance of platform displacement from its desired location with both fixed and steerable antennas are also examined. It is shown that steerable antennas are of most use when fixed stations are immediately below the platform, with no benefit for fixed stations on the edge of coverage. The bandwidths required to serve several traffic distributions (suburbs and city centre based) are evaluated using the Shannon equation. It is shown that capacity can be constrained when users are located in the city centres, despite longer line of sight paths to users out in the suburbs. The effects of temporal changes in the spatial traffic distribution are investigated. It is shown that bandwith requirements can be reduced if the platform moves to track these changes. Copyright © 2001 John Wiley & Sons, Ltd. [source]

The Coffee Shop: Social and Physical factors Influencing Place Attachment

JOURNAL OF INTERIOR DESIGN, Issue 3 2006
Lisa Waxman Ph.D
ABSTRACT This study explored the characteristics that encourage gathering behavior and contribute to place attachment in selected coffee shops in the context of literature suggesting social gathering places contribute to social capital. These gathering places, with the potential to enhance community in this manner, have been called third places. The study was qualitative in nature and included the research techniques of visual documentation, observation and behavioral mapping, interview, and survey. A transactional approach to this study was chosen to better understand the meaning of the person-environment relationship. Each coffee shop was observed for twenty-five hours for a total of seventy-five hours. Eighteen interviews were conducted and surveys were collected from 94 patrons to reveal patron attitudes toward the physical and social aspects of the coffee shop as well as their feelings regarding the community in which they live. The key findings regarding the physical characteristics showed the top five design considerations included: cleanliness, appealing aroma, adequate lighting, comfortable furniture, and a view to the outside. A number of themes emerged related to people, their activities, and their feelings and attitudes regarding the coffee shop. Each coffee shop was found to have a unique social climate and culture related to sense of belonging, territoriality and ownership, productivity and personal growth, opportunity for socialization, support and networking, and sense of community. Regarding feelings of community, survey findings from coffee shops patrons showed a positive correlation between length of patronage and their sense of attachment to their community. [source]

Dual band,rejected microstrip antenna for WiMAX/WLAN applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010
Shun-Yun Lin
Abstract In this article, we propose a novel design to obtain dual band,rejected characteristics in printed microstrip antenna.First, an ultrawide operating band from 2.15 GHz to about 6.50 GHz is achieved by locating the rectangular radiating patch above a larger rectangular notch cut in the finite ground plane edge. Two folded strips with different length protrude from the patch corner with null surface current to introduce dual rejected band. The longer strip and shorter strip are independently associated with lower and upper rejected band. By suitable adjustment in strip lengths, two rejected bands centered at 3 and 4.7 GHz are successfully introduced. Also, a triband operation for 2.5/3.5/5.5 GHz WiMAX and 2.4/5.2/5.8 GHz WLAN applications is achieved for the proposed microstrip antenna. Details of the design considerations are presented, and results of the implemented prototype are discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1901,1905, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25312 [source]

An introduction to coil array design for parallel MRI

NMR IN BIOMEDICINE, Issue 3 2006
Michael A. Ohliger
Abstract The basic principles of radiofrequency coil array design for parallel MRI are described from both theoretical and practical perspectives. Because parallel MRI techniques rely on coil array sensitivities to provide spatial information about the sample, a careful choice of array design is essential. The concepts of coil array spatial encoding are first discussed from four qualitative perspectives. These qualitative descriptions include using coil arrays to emulate spatial harmonics, choosing coils with selective sensitivities to aliased pixels, using coil sensitivities with broad k -space reception profiles, and relying on detector coils to provide a set of generalized projections of the sample. This qualitative discussion is followed by a quantitative analysis of coil arrays, which is discussed in terms of the baseline SNR of the received images as well as the noise amplifications (g -factor) in the reconstructed data. The complications encountered during the experimental evaluation of coil array SNR are discussed, and solutions are proposed. A series of specific array designs are reviewed, with an emphasis on the general design considerations that motivate each approach. Finally, a set of special topics is discussed, which reflect issues that have become important, especially as arrays are being designed for more high-performance applications of parallel MRI. These topics include concerns about the depth penetration of arrays composed of small elements, the use of adaptive arrays for systems with limited receiver channels, the management of inductive coupling between array elements, and special considerations required at high field strengths. The fundamental limits of spatial encoding using coil arrays are discussed, with a primary emphasis on how the determination of these limits impacts the design of optimized arrays. This review is intended to provide insight into how arrays are currently used for parallel MRI and to place into context the new innovations that are to come. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The cask age: the technology and history of wooden barrels

PACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2005
Diana Twede
Abstract This paper explores the use of wooden casks (barrels). It shows the principles of their construction, organization of the cooper industry over time and examples of how barrels facilitated trade and logistical activities throughout the 2000 years in which they were a predominant shipping container form. The paper finds that, although the shape and construction are very different from today's shipping containers, the same design considerations apply. Package shape and weight were designed to promote material handling productivity. The geometry facilitated transport by maximizing cube utilization and tight stowage in ships and wagons. The materials and technology were readily available at low cost. The construction provided protection from handling and transit forces. Trade associations cooperated to set standards for quality control, developed educational programs and worked with governments to regulate standards. Printing identified product and stock keeping units (product and brand). The shelf-life of food products was extended. The closure permitted easy filling and closing, stayed closed during transit, and facilitated opening and emptying. Containers were widely reused or recycled. The reasons for the end of the barrel era relate to changes in technology, logistics, markets and overall economic activity. The industrial revolution created an increase in demand and stimulated mechanization, resulting in lower quality barrels as well as the development of other substitutes. The trend to paper-based substitutes was enabled by the invention of the papermaking machine and the process for pulping wood in the 1800s. Rail transport changed the geometry of transport vehicles and enabled mechanical handling practices that favoured the box shape. These innovations enabled a shift in marketing and retailing, ushering in the consumer packaging revolution. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Design, process, and performance of all-epitaxial normally-off SiC JFETs

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2009
Rajesh K. Malhan
Abstract This paper reviews the normally-off (N - off) and normally-on (N - on) SiC junction field effect transistor (JFET) concepts and presents an innovative all-epitaxial double-gate trench JFET (DGTJFET) structure. The DGTJFET design combines the advantages of lateral and buried gate JFET concepts. The lateral JFET advantage is the epitaxial definition of the channel width and the buried gate JFET advantage is the small cell size. In the DGTJFET process the epitaxial embedded growth in trenches facilitates the small cell pitch and the vertical direction of the channel. A detailed numerical simulation analysis compares the potential of the DGTJFET design with reported lateral channel and buried gate JFET structures. Migration enhanced embedded epitaxy (ME3) and planarization processes were developed to realize narrow cell pitch DGTJFETs for high-density power integration. The highly doped vertical channel of the DGTJFET defined by the ME3 growth process makes it possible to accurately control the sub-micron channel dimensions in order to realize a low specific on-state resistance (RON) and a high saturation current capability. The anisotropic nature of SiC is taken into account for the channel design considerations. The successful application of the new process technologies for the development of the all-epitaxial DGTJFETs is discussed. Fabricated 5.5 ,m cell pitch 4H-SiC DGTJFETs demonstrate the saturation current density capability of more than 1000 A/cm2. N - off and N - on DGTJFETs with 2.25 mm squared chip size and 9.5 ,m cell pitch output 15 A and 20 A at gate voltage of 2.5 V and drain voltage of 5.0 V. The specific RON of the N - off and N - on DGTJFETs is at room temperature 8.1 m , cm2 and 6.3 m, cm2, respectively, indicating that N - off devices can be realized at the expense of a slight increase in specific RON of approximately 25%. DGTJFETs with a 13 ,m drift layer doped to 5.0 × 1015 cm,3 are demonstrated with a breakdown voltage in the range of 1200 V to 1550 V at the wafer level with a leakage current below 10 ,A. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A Statistical Framework for Quantile Equivalence Clinical Trials with Application to Pharmacokinetic Studies that Bridge from HIV-Infected Adults to Children

BIOMETRICS, Issue 4 2008
Lixia Pei
Summary Bridging clinical trials are sometimes designed to evaluate whether a proposed dose for use in one population, for example, children, gives similar pharmacokinetic (PK) levels, or has similar effects on a surrogate marker as an established effective dose used in another population, for example, adults. For HIV bridging trials, because of the increased risk of viral resistance to drugs at low PK levels, the goal is often to determine whether the doses used in different populations result in similar percentages of patients with low PK levels. For example, it may be desired to evaluate that a proposed pediatric dose gives approximately 10% of children with PK levels below the 10th percentile of PK levels for the established adult dose. However, the 10th percentile for the adult dose is often imprecisely estimated in studies of relatively small size. Little attention has been given to the statistical framework for such bridging studies. In this article, a formal framework for the design and analysis of quantile-based bridging studies is proposed. The methodology is then developed for normally distributed outcome measures from both frequentist and Bayesian directions. Sample size and other design considerations are discussed. [source]

Polymerization and matrix physical properties as important design considerations for soluble collagen formulations

BIOPOLYMERS, Issue 8 2010
S. T. Kreger
Abstract Despite extensive use of type I collagen for research and medical applications, its fibril-forming or polymerization potential has yet to be fully defined and exploited. Here, we describe a type I collagen formulation that is acid solubilized from porcine skin collagen (PSC), quality controlled based upon polymerization potential, and well suited as a platform polymer for preparing three-dimensional (3D) culture systems and injectable/implantable in vivo cellular microenvironments in which both relevant biochemical and biophysical parameters can be precision-controlled. PSC is compared with three commercial collagens in terms of composition and purity as well as polymerization potential, which is described by kinetic parameters and fibril microstructure and mechanical properties of formed matrices. When subjected to identical polymerization conditions, PSC showed significantly decreased polymerization times compared to the other collagens and yielded matrices with the greatest mechanical integrity and broadest range of mechanical properties as characterized in oscillatory shear, uniaxial extension, and unconfined compression. Compositional and intrinsic viscosity analyses suggest that the enhanced polymerization potential of PSC may be attributed to its unique oligomer composition. Collectively, this work demonstrates the importance of standardizing next generation collagen formulations based upon polymerization potential and provides preliminary insight into the contribution of oligomers to collagen polymerization properties. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 690,707, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]