Smooth Side Research Articles

Effectively Well-Conditioned Linear Systems

When solving the linear system ${\bf A}x = {\bf b}$, the condition number $K(A) \equiv \| A \| \| A^{ - 1} \|$ is a useful, albeit often overly conservative, measure of the sensitivity of the solution ${\bf x}$ under perturbations $\Delta A$ and $\Delta {\bf b}$ to A and ${\bf b}$. We demonstrate how the projection of ${\bf b}$ onto the range space of A, in addition to $K(A)$, can strongly affect the sensitivity of ${\bf x}$ in specific problem instances. Two practical cases are presented in which the sensitivity of ${\bf x}$ can be substantially smaller than that predicted by $K(A)$ alone. In the first example, we characterize a class of Vandermonde matrices and right-hand sides for which accurate algorithms can exist. For the second example, we show that a (fast Fourier transform-) FFT-based fast Poisson solver can produce very accurate results for smooth right-hand sides. Computational examples on the fast Poisson solver are included to illustrate these concepts.

Partial regularity results for vector valued functions which minimize certain functionals having non quadratic growth under smooth side conditions.

Partial regularity results for vector valued functions which minimize certain functionals having non quadratic growth under smooth side conditions.

Heat Transfer and Friction Characteristics in Rectangular Channels With Rib Turbulators

The effect of the channel aspect ratio on the distribution of the local heat transfer coefficient in rectangular channels with two opposite ribbed walls (to simulate turbine airfoil cooling passages) was determined for a Reynolds number range of 10,000 to 60,000. The channel width-to-height ratios (W/H, ribs on side W) were 1/4, 1/2, 1, 2, and 4. The test channels were heated by passing current through thin, stainless steel foils instrumented with thermocouples. The local heat transfer coefficients on the ribbed side wall and on the smooth side wall of each test channel from the channel entrance to the fully developed regions were measured for two rib spacings (P/e = 10 and 20). The rib angle-of-attack was kept at 90 deg. The local data in the fully developed region were averaged and correlated, based on the heat transfer and friction similarity laws developed for ribbed channels, to cover the ranges of channel aspect ratio, rib spacing, rib height, and Reynolds number. The results compare well with the published data for flow in a square channel with two opposite ribbed walls. The correlations can be used in the design of turbine airfoil cooling passages.

Effect of Rib Angle on Local Heat/Mass Transfer Distribution in a Two-Pass Rib-Roughened Channel

The heat transfer characteristics of turbulent air flow in a two-pass channel were studied via the naphthalene sublimation technique. The test section, which consisted of two straight, square channels joined by a sharp 180 deg turn, resembled the internal cooling passages of gas turbine airfoils. The top and bottom surfaces of the test channel were roughened by rib turbulators. The rib height-to-hydraulic diameter ratio (e/D) was 0.063 and the rib pitch-to-height ratio (P/e) was 10. The local heat/mass transfer coefficients on the roughened top wall, and on the smooth divider and side walls of the test channel, were determined for three Reynolds numbers of 15,000, 30,000, and 60,000, and for three angles of attack (α) of 90, 60, and 45 deg. The results showed that the local Sherwood numbers on the ribbed walls were 1.5 to 6.5 times those for a fully developed flow in a smooth square duct. The average ribbed-wall Sherwood numbers were 2.5 to 3.5 times higher than the fully developed values, depending on the rib angle-of-attack and the Reynolds number. The results also indicated that, before the turn, the heat/mass transfer coefficients in the cases of α = 60 and 45 deg were higher than those in the case of α = 90 deg. However, after the turn, the heat/mass transfer coefficients in the oblique-rib cases were lower than those in the traverse-rib case. Correlations for the average Sherwood number ratios for individual channel surfaces and for the overall Sherwood number ratios are reported.

Beta-Sympathomimetic Agents: Use in Perinatal Obstetrics

Beta-sympathomimetic agents are used extensively in obstetrics to inhibit premature labor. Knowledge of the pharmacology, mode of action on smooth muscle, and cardiovascular and metabolic side effects of these agents is essential for the obstetrician and perinatologist. This review article draws extensively on recent animal research data to explain mechanisms of action and long-term effects of beta-sympathomimetic agents.

Control of Etching of LiNbO3, by Implant Damage Profile Tailoring

ABSTRACTDamage-profile tailoring using multi-energy ion implants can produce smooth side walls and deeper etched features with ion-bombardment-enhanced wet etching of LiNb03 than is possible with a single-energy implant. High ion fluences can produce buried microcracks which may contribute to propagation losses commonly observed in ion-implanted waveguides.

Effects of surface characteristics on the change of metallic glass structure and magnetoelastic properties induced by laser heat treatment

Laser annealing of amorphous alloy ribbons was performed by irradiating either their smooth or rough side. Experimental results such as hyperfine field distributions, average orientation of the magnetic moment, X-ray diffractography, initial permeability, magnetic anistropy, and low field magnetization, show the influence of the surface characteristics on the effects induced by the laser treatment. In particular, the effects of an applied tensile stress are compared to eachother and with previously obtained results. Many results are explained by means of the crystallization occurrence (at surface and also bulk) and taking into account its dependence on the irradiated surface properties and interaction time.

Comprehensive calculation of convertor harmonics with system impedances and control representation

The paper describes a computational method for finding the harmonics in large convertor systems, with particular reference to the interdependent effects of convertors, transformers, AC and DC system representation and convertor controls. This work is of particular concern as the number of HVDC schemes and large drive systems increases within AC power systems. The method described is comprehensive in that it can model, for example, unbalanced AC system voltages and impedances; any type of convertor transformer arrangement; virtually any pulse number; harmonic filters, a non-infinite AC system representation; it does not assume a smooth DC side current and can include the effect of system resonances in both the AC and DC system. Within the bridge convertors, such features as firing unbalance, convertor transformer saturation, unequal commutation overlaps and the effect of the two principal control methods are all easily modelled. If a comprehensive method is not used, the results of an harmonic study could give unrealistic results. This is shown by example.

Relaxation of asymmetric 2-D channel flow into symmetric state caused by a step change in wall roughness (1st report, Characteristics of mean velocity field)

Experiments have been conducted in the 7m channel where one of the walls in the upstream half was roughened and all the remaining parts were left smooth, providing a fully developed asymmetric flow at the midsection and a fully developed symmetric flow at the channel exit. Extensive measurement of the mean velocity, Reynolds normal and shear stresses made downstream of the step change in wall roughness indicate that the readjustment to a symmetric flow requires a streamwise distance of 50 times the channel height 2h; whereas the evaluation of the momentum equation shows that for x/h6gt;20 the pressure gradient balances practically with the wall shear stress. It is found also that the adjustment process is quite different between the rough to smooth and the smooth to smooth sides. Non-monotonical adjustment is essential only in the rough to smooth side.

Temperature-sensitive mutants in rfaI and rfaJ, genes for galactosyltransferase I and glucosyltransferase II, for synthesis of lipopolysaccharide in Salmonella typhimurium

Certain rough mutants of Salmonella typhimurium LT2 were shown to be temperature sensitive for the production of lipopolysaccharide (LPS). When grown at the restrictive temperature (42 or 45 degrees C), the cells contained LPS deficient in O (somatic) side chains, based on phage-sensitivity data and gel electrophoresis of the LPS. Cells grown at the permissive temperature, 30 degrees C, made LPS resembling that of smooth cells. The mobility of the LPS in gels, the phage sensitivity patterns, and gas chromatographic analysis indicate that LPS of 45 degrees C-grown cells of SA126 (rfaJ3012) is of chemotype Rb2, with one glucose and two galactose units (and thus inferred to be due to a mutation in rfaJ), and LPS of 45 degrees C-grown cells of SA134 (rfa13020) is of chemotype Rb3, with one glucose and one galactose unit (inferred to be rfaI). These inferences were confirmed, for pKZ26 (pBR322-rfaGBIJ) and pKZ27 (pBR322-rfaGBI) both complement rfaI3020, but only pKZ26 complemented rfaJ3012. In addition, pKZ26 carrying a Tn5 insertion resulting in loss of complementation of a known rfaJ mutation, but not of rfaG, B, or I, also resulted in loss of rfaJ3012 complementation. Based on gel analysis, there is a small amount of the LPS containing smooth side chains in cells of SA126 grown at 45 degrees C; following a switch to 30 degrees C, the amount of LPS with O side chains gradually increased, and the amount of core LPS was reduced, though even after 3 h the LPS does not fully resemble that of smooth strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Anisotropic reactive ion etching technique of GaAs and AlGaAs materials for integrated optical device fabrication

This paper reports a reactive ion etching (RIE) technique using a Cl2–Ar gas mixture for anisotropic microprocessing of GaAs and AlGaAs materials and its fundamental characteristics aimed to applications to monolithic integration of optical devices. This technique allows one to realize very fine as well as deep processing perpendicular to the wafer surface with smooth side walls, independent of the crystallographic orientation of these semiconductor materials. The etching rate was found to be controllable over a wide range by suitably adjusting the gas composition and the total gas pressure in this gas mixture. We experimentally obtained the optimum condition for smooth and perpendicular etching for both the materials at the total gas pressure of 2 Pa (1.5×10−2 Torr) with the gas flow ratio of Cl2 : Ar=1 : 5. Under this condition the etching rate ratio of GaAs to SiO2 was demonstrated more than 70. The surface damage introduced by this RIE was confirmed to be comparable at least to the case of the wet chemical etching through the measurement of photoluminescence intensities from GaAs samples.

A model of destruction of brittle rock with a system of oriented cracks under pressure

The authors examine a model of a crack with rough sides. In the approximation of plane deformation, they define the conditions of destruction of brittle rock with a system of cracks oriented along the line of compression. These results were used to conduct experiments in the destruction of weak concrete blocks with artificially cut parallel cracks under uniaxial and biaxial compression. Results show that the extrusion mechanism accounts for a reduction of strength of the body with a system of cracks oriented along the lines of compression. The strong discrepancy between experimental and theoretic results remains unexplained, and it is especially surprising, because the discrepancy is observed in the region of sloping cracks where the model yields a result similar to that of the conventional method where the cracks are modeled by slits with smooth sides.

The Structural Properties of Sputtered Zinc Oxide

ABSTRACTX-ray diffraction, chemical etching and electron microscopy are useful in delineating the microstructural properties of c-axis normal oriented polycrystalline zinc oxide films, sputter deposited on amorphous substrates. Dense ZnO films with high crystalline content and low etch rates have a strong piezoelectric effect and low surface acoustic wave and guided optical wave propagation loss. The structural properties are dependent upon substrate conditions, deposition parameters and the type of sputtering system used. Scanning electron microscope examination of the surface and side fractures of high quality ZnO films show smooth continuous upper surface and side regions with no vertical fiber grain structures apparent. Light chemical etching reveals surface defects consisting of uniformly distributed conical shaped etch pit structures with a lateral to vertical etch ratio of 3 to 1. A correlation has been made between film structure and single crystal zinc oxide. The structural picture which emerges is that of a predominantly positive polarity (0001) upper surface layer with localized negative polarity (0001) fiber grain inversions. The sputter conditions which lead to low defect density films are a high substrate temperature, high deposition rate and low reactive gas pressures to promote the adatom mobility necessary for the preferred (0001) zinc face growth. Post deposition laser and thermal annealing can be used to reduce stress in the films and improve their guided optical wave properties.

Hydraulic Jump Properties Over a Rough Bed

Hydraulic jump characteristics were measured over several artificially roughened test beds in a horizontal rectangular flume with smooth side walls. A smooth test bed, two strip roughness test beds and three densely packed gravel test beds provided a relative roughness range from 0.0–0.9. The testing program involved some 200 hydraulic jump observations which included flow rate, upstream depth, tailwater depth and jump length. Observations showed that boundary roughness reduces both the sequent depth and the length of a hydraulic jump, and that the observed reductions were related to both Froude number and the degree of roughness. The observed hydraulic jump characteristics were consistent with theory, and a proposed approximation for a theoretical hydraulic jump equation was found to compare favorably with the observed characteristics.

Residual Sprays to Control Insects in Warehouses, 1983

Abstract Three representative building materials of low economy grade were used in warehouse tests to assess the relative effectiveness of encapsulated diazinon, diazinon emulsion, and malathion emulsion spray residues against laboratory-reared mature larvae of the warehouse beetle and young adults of the cigarette beetle, the confused flour beetle, and the sawtoothed grain beetle. Squares of aluminum with kraft paper backing 1 ft2 attached with double-stick tape to press board squares of the same size, the smooth side of press-board panels measuring 2 by 4 ft, and 18- in. square concrete stepping stones were sprayed with insecticides from a Namco compressed air sprayer with a fan nozzle (no. 800067). Surfaces were wet with spray as required by the different substrates, but application was stopped before run off. Sufficient substrate was treated with each concentration used to provide eight exposure replications with each test species for aging dates of 1, 7, 14, and 28 days. Sprays were applied and insects were exposed to treated surfaces in the early morning when the 6,300 ft3 warehouse was cool; residues were aged in the warehouse with extreme ambient climatic conditions ranging from low night temp of 58°F and 90% RH to the highest day temp of 112°F and 20% RH. Twenty-five specimens of each species were contained in 7.5-cm diam fluon-treated glass cylinders to keep insects on treated surfaces of each treatment replication. Cylinders on concrete surfaces were ringed at their base with a nontoxic caulking material to prevent escape of insects, and a filter paper cover was put on cylinders to prevent escape of flying cigarette beetles. After an exposure of 2 h on treated surfaces, test insects were removed and placed on food in fresh containers. Then they were held 7 days in a room maintained at 80°F and 50% RH before mortalities were recorded. Appropriate controls were included in the test and mortalities shown in the tabulation of results were corrected for natural mortality, although few insects died in control samples.

Scanning light spot scan and electron-beam-induced current studies of CdS/Cu xS solar cells formed on rough and smooth single-crystal CdS substrates

CdS/Cu x S solar cells prepared on a single-crystal CdS substrate, half of which has been roughened by an HCl etch, are examined using scanning light spot and electron-beam-induced current scans. It is shown that the roughened side of the cell has a greater response than the smooth side and that the response of the rough side is improved by an anneal whereas there is no improvement on the smooth side. We suggest that this is because the structure of the Cu x S on the rough surface side is different from that on the smooth surface side and is improved after an anneal. We also show that the response of a cell fabricated on a CdS bicrystal is lower in the crystallite with more internal stress and that the response on the smooth surface side of the cell decays more slowly.

Description of the Aeolid Nudibranch Favorinus tsuruganus Baba and ABE, 1964 From Eastern Australia

Favorinus tsuruganus Baba and Abe, 1964 (Opisthobranchia: Nudibranchia) is redescribed from material taken in Queensland and New South Wales waters. Characters of its external anatomy, alimentary and reproductive systems (e.g., structures of propodial tentacles, ceratal arrangement, jaws, penis), as well as the behaviour of living animals agree well with those known not only for Japanese specimens but also for Favorinus species in general. The radular teeth are unusual, but not exceptional, in having smooth sides to the cusp. Coloration and shape of the rhinophores are the most distinctive features.

Degranulation, membrane addition, and shape change during chemotactic factor-induced aggregation of human neutrophils.

Neutrophils stimulated by the chemotactic factor formyl-methionyl-leucyl-phenyl-alanine (FMLP) undergo a transient change in surface properties that permits the cells to adhere more readily to surfaces and to each other. This transient change can be monitored by light scattering as stimulated neutrophils form aggregates while stirred in a platelet aggregometer. Maximum change in light scattering occurs within 1 min and correlates with an increase in the percentage of cells that are in aggregates of four or more cells and a decrease in the percentage of single cells. With time (3-5 min), small aggregates disappear and single cells reappear. The transient change in adhesiveness is accompanied by a persistent change in cell shape; the cells become polarized and protrude ruffles from one sector of the cell surface. During aggregation the cells adhere to one another with smooth sides together and ruffles pointed outward. During disaggregation the cells dissociate laterally with the simultaneous internalization of membrane in the region opposite the ruffles. Particle bound to the surface by charge (thorotrast, cationized ferritin) are concentrated and internalized in this region. The change in cell shape from round to ruffled occurs within seconds, suggesting that membrane is added to the cell surface from an intracellular store. We therefore quantified surface membrane by electron microscopy morphometry and measured a 25% increase within 10 s of adding FMLP. The source of new membrane appeared to be the specific granule membrane since the kinetics of granule discharge (between 30% and 50% of all release occurs in the first 10 s) correlate with the appearance of new membrane. Furthermore, the amount of membrane that appears at the cell surface at 10 s correlates with that lost from intracellular granules in that time. Chemotaxin-induced aggregation thus begins with granule discharge and membrane addition followed by protrusion of ruffles. Adherence is maximal at 60 s and the gradual loss of adhesiveness that follows is associated with uropod formation and enhanced endocytic activity.

The crystal structure of cholesteryl dihydrogen phosphate

Crystals of cholesteryl dihydrogen phosphate grown from 1,4-dioxane solution are monoclinic, space group C2 with a = 24.40, b = 6.27, c = 40.86 A ̊ and β = 102.7° . The asymmetric unit contains two molecules of cholesteryl phosphate CP and one dioxane molecule of the solvent. The CP molecules pack tail to tail in a bilayer structure. Within the layer they are arranged in double rows with their phosphate groups linked to ribbons by hydrogen bonds. Laterally the double strands of phosphate groups are separated by rows of dioxane molecules. The dioxane serves as hydrogen bond acceptor and as a spacer molecule that compensates the differences in cross-sectional area of the cholesteryl residue (38.4 Å 2 and the phosphate group (24 Å 2). In the cholesterol matrix the CP molecules joined to double rows have packing contact with the smooth side of their skeleta and interdigitate with their annular methyl groups with those of molecules of the adjacent double rows. The branched cholesteryl side chains facing the bilayer center are loosely packed and show considerable disorder and/or thermal motion.

The Problem of Axially Symmetric Flow of Ideal Rigid‐Plastic Huber‐Mises Medium without any Specific Hypotheses

AbstractIn contrast to Shield' or Lippmann' solution in the present paper the Huber‐Hencky‐Mises' yield condition, more suitable for metals than Tresca', is adopted. Moreover, the Haar‐Kármán hypothesis and also any assumptions substituting it, as that used by Lippmann, with the errors introduced by them are avoided.Instead of this, two ratios of stress (or respective strain rate) deviator components to one another are introduced as unknown functions α and β and the parameter λ is eliminated. Then, the well‐known system of seven equations in seven unknown functions for solving the title problem is reduced to a system of two quasilinear partial integro‐differential equations in α and β. The boundary conditions of the problem for both α and β and their first derivatives are found, for a smooth side of the die, on the basis of kinematical and statical conditions. The system of equations is of the mixed type but a transformation of α reduces the problem to the hyperbolic region only. It is possible to find directly the proper solution and not, as usually, its lower and/or upper estimation only.