Unified functional decomposition via encoding for FPGA technologymapping

Functional decomposition has recently been adopted for look-up table (LUT)-based field-programmable gate array (FPGA) technology mapping with good results. In this paper we propose a novel method to unify functional single-output and multiple-output decomposition. We first address a compatible class encoding algorithm to minimize the number of compatible classes in the image function. After applying the encoding algorithm, we can therefore improve the decomposability in the subsequent decomposition of the image function. The above encoding algorithm is then extended to encode multiple-output functions through the construction of a hyperfunction. Common subexpressions among these multiple-output functions can be extracted during the decomposition of the hyperfunction. Consequently, we can handle multiple-output decomposition in the same manner as single-output decomposition. Experimental results show that our algorithms are promising     

3D modeling of subsurface fatigue crack nucleation potency of primary inclusions in heat treated and shot peened martensitic gear steels

A computational strategy is developed to characterize the driving force for fatigue crack nucleation at subsurface primary inclusions in carburized and shot peened C61^® martensitic gear steels. Experimental investigation revealed minimum fatigue strength to be controlled by subsurface fatigue crack nucleation at inclusion clusters under cyclic bending. An algorithm is presented to simulate residual stress distribution induced through the shot peening process following carburization and tempering. A methodology is developed to analyze potency of fatigue crack nucleation at subsurface inclusions. Rate-independent 3D finite element analyses are performed to evaluate plastic deformation during processing and service. The specimen is subjected to reversed bending stress cycles with R = 0.05, representative of loading on a gear tooth. The matrix is modeled as an elastic–plastic material with pure nonlinear kinematic hardening. The inclusions are modeled as isotropic, linear elastic. Idealized inclusion geometries (ellipsoidal) are considered to study the fatigue crack nucleation potency at various subsurface depths. Three distinct types of second-phase particles (perfectly bonded, partially debonded, and cracked) are analyzed. Parametric studies quantify the effects of inclusion size, orientation and clustering on subsurface crack nucleation in the high cycle fatigue (HCF) or very high cycle fatigue (VHCF) regimes. The nonlocal average values of maximum plastic shear strain amplitude and Fatemi–Socie (FS) parameter calculated in the proximity of the inclusions are considered as the primary driving force parameters for fatigue crack nucleation and microstructurally small crack growth. The simulations indicate a strong propensity for crack nucleation at subsurface depths in agreement with experiments in which fatigue cracks nucleated at inclusion clusters, still in the compressive residual stress field. It is observed that the gradient from the surface of residual stress distribution, bending stress, and carburized material properties play a pivotal role in fatigue crack nucleation and small crack growth at subsurface primary inclusions. The fatigue potency of inclusion clusters is greatly increased by prior interfacial damage during processing.     

Synthesis and swelling properties of 2‐hydroxyethyl methacrylate‐co‐1‐vinyl‐3‐(3‐sulfopropyl)imidazolium betaine hydrogels

A series of 2‐hydroxyethyl methacrylate/1‐vinyl‐3‐(3‐sulfopropyl)imidazolium betaine (HEMA/VSIB) copolymeric gels were prepared from various molar ratios of HEMA and the zwitterionic monomer VSIB. The influence of the amount of VSIB in copolymeric gels on their swelling behavior in water and various saline solutions at different temperatures and the drug‐release behavior, compression strength, and crosslinking density were investigated. Experimental results indicated that the PHEMA hydrogel and the lower VSIB content (3%) in the HEMA/VSIB gel exhibited an overshooting phenomenon in their dynamic swelling behavior, and the overshooting ratio decreased with increase of the temperature. In the equilibrium water content, the value increased with increase of the VSIB content in HEMA/VSIB hydrogels. In the saline solution, the water content for these gels was not affected by the ion concentration when the salt concentration was lower than the minimum salt concentration (MSC) of poly(VSIB). When the salt concentration was higher than the MSC of poly(VSIB), the deswelling behavior of the copolymeric gel was more effectively suppressed as more VSIB was added to the copolymeric gels. However, the swelling behavior of gels in KI, KBr, NaClO₄, and NaNO₃ solutions at a higher concentration would cause an antipolyelectrolyte phenomenon. Besides, the anion effects were larger than were the cation effects in the presence of a common anion (Cl^?) with different cations and a common cation (K⁺) with different anions for the hydrogel. In drug‐release behavior, the addition of VSIB increased the drug‐release ratio and the release rate. Finally, the addition of VSIB in the hydrogel improved the gel strength and crosslinking density of the gel. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2888–2900, 2001     

Chemical preparation of PLZT powders by the carbonate method

PLZT powders were prepared by the adsorption-type coprecipitation method, in which mixed ammonium carbonate and ammonium hydroxide aqueous solution was used as a precipitant. The resulting precipitates are mixtures of carbonates and hydroxides. After calcining at 600°C a powder was obtained, consisting of two phases of the zirconium-rich and the titanium-rich perovskite structures with lattice parameters of about 4·13 Å and 3·99 Å, respectively. As calcination temperature increased, these two phases tended to dissolve each other gradually, and then a single perovskite structure appeared as the temperature rose above 900°C. By the results of X-ray diffraction, SEM, TEM and DTA/TGA, the behavior of coprecipitated powders and calcining treatments have been discussed. The atmosphere sintering technique was used to examine the sinterability of the PLZT powders, and a transparent PLZT ceramic was thus obtained.     

On the rule of additivity in phase transformation kinetics

It is commonly held that a sufficient condition for the rule of additivity to be valid is that the transformation rate depend only on temperature and volume fraction. This is not true in general.     

Elevated-Temperature Creep of Silicon Carbide-Aluminum Nitride Ceramics: Role of Grain Size

Samples containing 50 mol% SiC and 50 mol% AIN were fabricated to neartheoretical density by hot-pressing in graphite dies in N₂ atmosphere. Grain size was varied by varying the hot-pressing conditions. Bar-shaped samples cut from the billets were subjected to creep deformation in four-point bending. Creep was found to depend upon the grain size with coarse-grained material exhibiting lower creep rate. The stress exponent was ∼2.0.     

Dengue: a re-emerging disease. A clinical and epidemiological study in 57 Spanish travelers

Dengue infection is nowadays considered a re-emergent disease. It has a worldwide tropical and subtropical distribution. The dengue virus in a member of the flavivirus family composed by 4 different serotypes. The virus is transmitted by mosquitos of the Aedes genus. With the increment of travels to the endemic areas, dengue is now observed frequently in our country. We analyzed 57 patients, 30 with imported dengue (ID) and 27 with dengue fever suffered during the trip (DDT). This series is compared with other published ones and a review of the subject is presented. Patients with ID followed a protocol as a febril syndrome returning from the tropics. Dengue was diagnosed through a compatible clinico-epidemiological history, the absence of other ferbil illness and positivity of specific serology. All patients had travelled to endemic areas (Central America 28 cases, Indian subcontinent 15, South-East Asia 10, South America 2, West Africa one, and Pacific one). The following were the most important clinical characteristics: fever and asthenia (100%), headache (98%), mialgia (84%), arthralgia (72%), morbilliform rash (61%) and retroocular pain (65%). For ID cases, the most helpful analitical results were: leucopenia (70%), reactive lymphocytes in peripheral blood smear (70%), thrombocytopenia (70%), and increased hepatic enzymes ALAT (53%), ASAT (63%) and LDH (100% in the 7 patients tested for this enzyme). Dengue must be included in differential diagnosis of fever in patients coming back to travels to tropical areas.     

Heat and mass transfer on the wavy film absorption process

Recently the absorption heat pumps and chillers have received considerable attention due to their low electricity consumption rate. Therefore, it is important to understand the transport mechanism of an absorption process. In this paper, a numerical study of the heat and mass transfer taking place on a wavy falling liquid film of an absorption process is presented. With previously solved periodic wavy film flow solutions, the finite difference method is employed to solve the heat and mass transport equations. The numerical solution indicates that the waves significantly increase the transport rates. A comparison of the transfer rates of the wavy film to that of the smooth film is presented to show that the mass transfer rate can be doubled.     

Timing-Driven Partial Scan

This partial scan approach reduces area overhead and performance degradation caused by test logic. Given an initial design that meets a target speed, the authors' algorithm selects a set of scan flip-flops that allows the circuit to meet performance requirements after the scan logic is added. If no such set exists, the algorithm selects a set that minimizes the total area increase caused by the scan logic and the subsequent performance optimization the circuit requires to meet target speed