Accuracy Assessment of Upwind Algorithms for Steady-state Computations

Upwind schemes have been evaluated for their accuracy based upon steady-state solutions of Euler and Navier–Stokes equations. It includes the flux-vector splitting schemes due to Steger–Warming and Van Leer, flux-difference splitting schemes due to Roe and Osher, and the hybrid schemes, AUSM (Advection Upstream Splitting method) and HUS (Hybrid Upwind Splitting). Computations for inviscid and viscous compressible flows that are well documented in literature have been carried out in a unified framework. Comparisons of lift, drag, skin-friction and heat-transfer coefficients have been established with reference computational and experimental results.     

Characterization and reliability of dual high-k gate dielectric stack (poly-Si-HfO/sub 2/-SiO/sub 2/) prepared by in situ RTCVD process for system-on-chip applications

We investigate for the first time the possibility of integrating chemical vapor deposition (CVD) HfO/sub 2/ into the multiple gate dielectric system-on-a-chip (SoC) process in the range of 6-7 nm, which supports higher voltage (2.5-5 V operation/tolerance). Results show that CVD HfO/sub 2/-SiO/sub 2/ stacked gate dielectric (EOT =6.2 nm) exhibits lower leakage current than that of SiO/sub 2/ (EOT =5.7 nm) by a factor of /spl sim/10/sup 2/, with comparable interface quality (D/sub it//spl sim/1/spl times/10/sup 10/ cm/sup -2/eV/sup -1/). The presence of negative fixed charge is observed in the HfO/sub 2/-SiO/sub 2/ gate stack. In addition, the addition of HfO/sub 2/ on SiO/sub 2/ does not alter the dominant conduction mechanism of Fowler-Nordheim tunneling in the HfO/sub 2/-SiO/sub 2/ gate stack. Furthermore, the HfO/sub 2/-SiO/sub 2/ gate stack shows longer time to breakdown T/sub BD/ than SiO/sub 2/ under constant voltage stress. These results suggest that it may be feasible to use such a gate stack for higher voltage operation in SoC, provided other key requirements such as V/sub t/ stability (charge trapping under stress) can be met and the negative fixed charge eliminated.     

DEVELOPMENTS AND CHALLENGES IN FLAVOR PERCEPTION AND MEASUREMENT—A REVIEW

Flavor perception and measurement play important roles in the development of food products. In an increasingly commercial environment, the food industry must strive to minimize adverse consumer reactions. This article gives an extensive overview on the various methods used for flavor measurement. Principles of flavor release and perception are discussed and applications to quality assessment are demonstrated.     

MODELING OF INTEGRATED MANUFACTURING SYSTEMS USING AN OBJECT-ORIENTED APPROACH

Traditional approaches to the modeling of complex manufacturing systems are expensive, time consuming, and of limited value. Recent developments in several areas (i.e., knowledge engineering, software engineering, modeling formalisms, engineering workstations, and database systems) are now to the point that a meaningful convergence can be crafted to yield a modeling environment far superior to any we have known in the past. Fundamental to this new approach to modeling are the recent developments in object-oriented programming and related technologies. A research team at Oklahoma State University has been exploring alternative approaches to the modeling and simulation of complex manufacturing systems since 1985. This paper argues for a fundamental paradigm shift in the development and utilization of models within a CEM framework.     

Ultrasmall Nanoplatforms as Calcium‐Responsive Contrast Agents for Magnetic Resonance Imaging

The preparation of ultrasmall and rigid platforms (USRPs) that are covalently coupled to macrocycle‐based, calcium‐responsive/smart contrast agents (SCAs), and the initial in vitro and in vivo validation of the resulting nanosized probes (SCA‐USRPs) by means of magnetic resonance imaging (MRI) is reported. The synthetic procedure is robust, allowing preparation of the SCA‐USRPs on a multigram scale. The resulting platforms display the desired MRI activity—i.e., longitudinal relaxivity increases almost twice at 7 T magnetic field strength upon saturation with Ca²⁺. Cell viability is probed with the MTT assay using HEK‐293 cells, which show good tolerance for lower contrast agent concentrations over longer periods of time. On intravenous administration of SCA‐USRPs in living mice, MRI studies indicate their rapid accumulation in the renal pelvis and parenchyma. Importantly, the MRI signal increases in both kidney compartments when CaCl₂ is also administrated. Laser‐induced breakdown spectroscopy experiments confirm accumulation of SCA‐USRPs in the renal cortex. To the best of our knowledge, these are the first studies which demonstrate calcium‐sensitive MRI signal changes in vivo. Continuing contrast agent and MRI protocol optimizations should lead to wider application of these responsive probes and development of superior functional methods for monitoring calcium‐dependent physiological and pathological processes in a dynamic manner.     

Studies of light scattering from ethnic hair fibers

One of the most desirable hair attributes to consumers, irrespective of ethnic background, is hair shine. The light reflected from a fiber has two components, specular and diffuse. The specular fraction of reflected light from the front surface of the fiber is generally recognized as a contributor to high luster. The distinction between specular and diffuse reflection is, however, not always clearly defined. In this study an attempt has been made to differentiate between specular and diffuse reflectance by analyzing mathematically goniophotometric curves of light reflected from unaltered single hair fibers from European, African, and Asian ethnic groups. The effect of macroscopic characteristics of the hair fibers, such as fiber diameter, cross-sectional shape, and curvature on luster is demonstrated. Results indicate that broadening of the specular peak reduces luster values, and is related to these characteristics. Thus, specular peak broadening is one of the important features to take into account when evaluating luster. Therefore, a new method for luster evaluation from goniophotometric curves is proposed. Additionally, we present the general model for light scattering, showing how scattering by surface roughness of different origin and magnitudes, and the scattering and absorption processes by the hair's interior, affect the position of the specular reflectance peak and its broadening.     

Functional perspectives on innovation: The correlates of innovationin the marketing and manufacturing functions

Existing knowledge about the correlates of innovation and the context of strategic decisions is used to develop propositions about the differences in the correlates of innovation in marketing and manufacturing functions. The theoretical model proposed is eclectic: it draws upon theory development in the fields of economics, engineering management, and corporate strategy. It is proposed that manufacturing managers link their innovation decisions to their assessment of the product's uniqueness in comparison with competitor's products. In contrast, marketing managers link their innovation decisions to the clarity of innovation objectives based on the customers' needs. The analysis of data from key informants in 172 firms is used to test the propositions. Whereas product uniqueness and clarity are significant correlates of innovation in the total sample, support is found for the proposition that the manufacturing subgroup focuses more on clarity     

Thoracic duct-cutaneous fistula in a patient with cirrhosis of the liver: successful treatment with a transjugular intrahepatic portosystemic shunt

Patients with cirrhosis of the liver have increased hepatic and gastrointestinal lymph flow that may contribute to the formation of ascites and pleural effusions. Increased lymph flow, which is due to postsinusoidal portal hypertension, causes a high rate of flow through the thoracic duct. Because of the high flow rates, disrupted lymphatic vessels in patients with cirrhosis of the liver may fail to close, a situation that results in chylous ascites, pleural effusions, or chylous fistulas. Chylous fistulas deplete proteins, fluid, and lymphocytes and thus lead to volume depletion and coagulopathy. Herein we describe an unusual case in which a high-output traumatic thoracic duct-cutaneous fistula developed in a patient with cirrhosis and led to volume depletion and coagulopathy. Correction of the portal hypertension with placement of a transjugular intrahepatic portosystemic shunt led to closure of the fistula and normalization of accompanying metabolic abnormalities.     

Adaptive-modulation schemes for minimum outage probability in wireless systems

Adaptive-modulation schemes are designed that yield the minimum outage probability for wireless systems with strict delay constraints, under the assumption of perfect causal channel state information at the transmitter and receiver. Numerical results indicate that the proposed schemes significantly outperform adaptive schemes designed to maximize the average rate.