Refocus attention span networks for handwriting line recognition

International Journal on Document Analysis and Recognition (IJDAR) - Recurrent neural networks have achieved outstanding recognition performance for handwriting identification despite the enormous...     

Note: Refractive index sensing of turbid media by differentiation of the reflectance profile: Does error-correction work?

A widely used method for determining refractive index postulates that the derivative of the angular profile for light reflected from the sample is maximum at the critical angle for total internal reflection (TIR). It is well-known that in turbid media this "differentiation method" yields errors in refractive index. Unexplained anomalies in previous error-calculations are eliminated if one uses a recent model of TIR which departs from traditional Fresnel theory. However we find that, in practical situations, the refractive index obtained by differentiation even after error-correction is significantly different from the best estimate for the refractive index obtained by curve-fitting the reflectance data. Thus the differentiation method lacks scientific validity in turbid media.     

Superplastic forming ability of as‐cast AZ91 Mg alloy prepared by twin roll casting

In this study, the twin roll casting process has been utilized to prepare initial as‐cast strip of AZ91 alloy that has been further tested in uniaxial tension at 325, 350 and 375 ºC, and at strain rates from 10^–2 to 10^–4 s^–1. The ability of AZ91 strip to undergo superplastic or superplastic‐like deformation in longitudinal direction, in transverse direction, and in 45 degrees to longitudinal direction was investigated with no further thermal or thermomechanical processing applied prior to the testing. At temperature 350 ºC and medium strain rate the maximum elongation reached almost 200% in direction parallel to the strip casting, however in the transverse and 45 degrees direction, different temperature, and at higher strain rates the maximum elongation was lower. Based on microstructural investigation by means of optical microscopy and scanning electron microscopy (SEM) it could be seen that continuous dynamic recrystallization of initial coarse dendritic as‐cast microstructure during elevated temperature deformation is active and responsible for high elongations. Additional analysis is provided by means of a strain rate sensitivity characterization and its evolution with increased level of strain. Strain rate sensitivity of AZ91alloy increased with increasing level of strain from 0.20 to 0.33.     

Stokes flow past a swarm of porous approximately spheroidal particles with Kuwabara boundary condition

The solution of the problem of symmetrical creeping flow of an incompressible viscous fluid past a swarm of porous approximately spheroidal particles with Kuwabara boundary condition is investigated. The Brinkman equation for the flow inside the porous region and the Stokes equation for the outside region in their stream function formulations are used. As boundary conditions, continuity of velocity and surface stresses across the porous surface and Kuwabara boundary condition on the cell surface are employed. Explicit expressions are investigated for both inside and outside flow fields to the first order in a small parameter characterizing the deformation. As a particular case, the flow past a swarm of porous oblate spheroidal particles is considered and the drag force experienced by each porous oblate spheroid in a cell is evaluated. The dependence of the drag coefficient on permeability for a porous oblate spheroid in an unbounded medium and for a solid oblate spheroid in a cell on the solid volume fraction is discussed numerically an and graphically for various values of the deformation parameter. The earlier known results are then also deduced from the present analysis.     

Neurohormonal regulation of histamine release from isolated rabbit fundic mucosal cells

Histamine-containing cells isolated from rabbit fundic mucosa were found in a small cell elutriation fraction (cells with diameter about 9-12 microns) enriched in mucus and endocrine cells and containing less than 1% mast cells (F1 cells). Gastrin (HG-17), pentagastrin and CCK-8 (C-terminal octapeptide of cholecystokinin) dose-dependently stimulated histamine release (EC50, respectively, 0.126 +/- 0.03, 0.92 +/- 0.15 and 0.211 +/- 0.025 nM) and somatostatin inhibited this release. PGE1, PGE2 and PGD2 alone were unable to enhance histamine release even at high concentrations but, when used in combination with gastrin of CCK-8, the release of histamine caused by these peptides was potentiated (about 1.5- to 2-fold). Carbachol also enhanced the liberation of histamine but with a weaker potency and efficacy than the gastrointestinal peptides (EC50: 1.50 +/- 0.06 microM). The use of specific muscarinic antagonists for M1-, M2- and M3-type receptors led us to conclude that an M1 receptor might be involved in the muscarinic-induced stimulation of histamine release. Activators of protein kinase C, 12-O-tetradecanoylphorbol-13-acetate (TPA) and 1-oleyl-2-acetyl-glycerol (OAG) as well as the calcium ionophore, A23187, induced histamine release, whereas agents which increased intracellular cAMP content were devoid of effect.(ABSTRACT TRUNCATED AT 250 WORDS)     

Application of Box–Wilson experimental design method for the photodegradation of textile dyestuff with UV/H2O2 process

Photodegradation of textile dyestuffs Chrysophenine Yellow (DY12), Congo Red (DR28) and Remazol Black B (RB5) by the UV/H₂O₂ process was investigated in a laboratory scale photoreactor equipped with a 16-W low-pressure mercury vapour lamp. The Box–Wilson experimental design was employed to evaluate the effects of major process variables, dyestuff and hydrogen peroxide concentrations and irradiation time on decolorization efficiency. Response function coefficients were determined by regression analysis of experimental data and predictions were found to be in good agreement with the experimental results. For 100 mg l⁻¹ DY12, RB5 and DR28 for instance, the optimum hydrogen peroxide concentration and irradiation time were found to be 45 mM for 58 min, 45 mM for 58 min and 60 mM for 120 min with 100, 100 and 85.7% efficiencies, respectively. Further increases in oxidant concentration led to slight decreases in decolorization efficiencies according to the response function, most probably due to the scavenging effect of excess hydrogen peroxide on hydroxyl radicals. And this was confirmed by the repeated experiments performed at the points of concern. Increasing the dyestuff concentration also decreased the decolorization efficiency even at higher concentrations of oxidant and longer irradiation times. The photodegradation of dyestuffs were found to follow a first-order reaction law.     

Model for Estimating Evaporation and Transpiration from Row Crops

Accurate estimates of crop evapotranspiration ETc, that quantify the total water used by a crop, are needed to optimize irrigation scheduling for horticultural crops and to minimize water degradation. During early growth, accurate assessments of ETc are difficult in vegetable crops because of high soil evaporation due to frequent irrigation. A model to estimate ETc for vegetable crops, using only daily reference evapotranspiration data as an input parameter, was developed. It calculates crop transpiration and soil evaporation based on ground cover and daily radiation intercepted by the canopy. The model uses a two-stage soil evaporation method adapted to conditions of variable reference evapotranspiration. The model was evaluated against data using measurements from two seasons of lettuce crop, two tomato fields in the same season, and one season of broccoli crop production. Using all of the crop data, the root-mean-square error for measured versus modeled daily ETc was 0.72 mm day?1, indicating that the model works well.     

Estimating Evaporation from Bare or Nearly Bare Soil

A model is presented that uses a daily mean evapotranspiration ETo rate to estimate energy-limited (potential or Stage 1) soil evaporation, and it also uses daily mean ETo and a soil hydraulic β factor to estimate soil hydraulic property-limited (Stage 2) evaporation. The model provides good estimates of cumulative soil evaporation on both hourly and daily bases when compared to observed soil evaporation in three field trials. Crop coefficient Kc values from cumulative hourly and cumulative daily soil evaporation estimates and ETo data were comparable. Using a soil hydraulic factor (β = 2.6) in the model gave a fair approximation for the widely used Kc curves for initial growth of crops presented in the United Nations Food and Agricultural Organization's Irrigation and Drainage Paper 24. However, using a site-specific β factor should improve soil evaporation and Kc estimates for site-specific applications.