Sublingual midazolam premedication in children: a dose response study

Regarding the development of a centrifugal blood pump to be connected directly with small diameter tubings for pediatric use while minimizing hemolysis, we have studied the inlet port side configurations of a pump using both a hemolysis test and computational fluid dynamics (CFD) analysis. We have conducted a hemolysis test on 2 models. The tapered shape inlet has proven to be lower in the index of hemolysis (IH) than the straight shape. CFD analyses utilizing expanded flow paths indicated that the flow velocity decreased as the fluid path became larger within the tapered nozzle. When entering the pump chamber, the flow rushed in at a greater velocity through the straight nozzle due to its small diameter. The straight shape showed an abrupt change in pressure around the entrance of the pump chamber while the tapered shape did not. The flow inlet angle of the straight model was observed to be larger than that of the tapered model because of its smaller turning radius.     

监控水系统中的异噻唑啉酮

本发明提供了一种测量水系统中异噻唑啉酮浓度的方法，包括通过降低从含有异噻唑啉酮的水系统中收集的样品pH去除样品的干扰，过滤水样，通过提高pH去除另外的干扰，接着过滤，选择性吸附水样中从吸附剂中脱吸的异噻唑啉酮，比较脱吸后样品与标准浓度样品的UV吸光值。     

Process Kinetics of Oxygen Steelmaking

The basic principles of chemical equilibrium and kinetics as they apply specifically to oxygen steelmaking are reviewed, the processes are analyzed, and some suggestions are made as to how oxygen steelmaking may be controlled more exactly.     

Analysis of factors that limit the production rate and coke rate in the iron blast furnace

An engineering analysis indicates that the coke rate in present blast-furnace practice is set not by chemical or thermal needs but to give adequate charge permeability for economical driving rates. An equation showing interrelations among pressure drop, gas flow, and charge characteristics has been derived. Flooding conditions and the location of the fusion zone are discussed. Maximum ore size is probably limited by chemical reducibility rather than by heat transfer.     

Kinetics of reactions between magnetite and carbon monoxide between 723 and 823 K

The kinetics of some reactions between carbon monoxide and magnetite were investigated between 723 and 823 K. Gas-phase mass-transfer effects within and near the porous samples and surface-reaction kinetics were considered. The experiments were done on sintered magnetite disks whose void fraction was 15 to 20 pct. A continuously weighed rotating disk reactor provided uniform mass transfer to the sample faces. The reacted disks were analyzed by Mössbauer spectroscopy and other methods. The only product species found were cementite and carbon, which suggested the existence of two reactions: the formation of cementite and carbon dioxide directly from magnetite and carbon monoxide, and the disproportionation of carbon monoxide to carbon dioxide and free carbon. These reactions were modeled mathematically. The surface kinetic data for both reactions were found to be compatible with rate expressions which were directly proportional to the square of the partial pressure of carbon monoxide and approximately inversely proportional to the partial pressure of product carbon dioxide.     

Thermodynamic study of Na2O-SiO2 melts at 1300° and 1400 °C

The vapor pressures of Na above stirred Na₂O-SiO₂ melts in equilibrium with graphite and CO were determined at 1300° and 1400 °C using the transpiration technique. Compositions studied ranged from about 60 mole pct SiO₂ to close to SiO₂ saturation. Activities of components Na₂O and SiO₂ were calculated from the data. Log a_Na2_O (pure liquid as standard state) varies from about −8.7 and −8.5 at silica saturation to −6.3 and −6.1 at 40 mole pct Na₂O at 1300° and 1400 °C, and the molar Gibbs energy of mixing, ΔG _m, at the disilicate composition (X_Na2_O = 0.33) at each of these temperatures is −83.0 and −85.4 kJ, respectively. The Toop and Samis, Yokokawa and Niwa, and Lin and Pelton solution models for binary silicates were applied to the ΔG _m data at 1350 °C and parameters for the models were estimated to give best fits. All three models show good correspondence with the measured ΔG _m curve. The capabilities of the models in predicting activity data in this system have been compared. D. N. Rego, Formerly Graduate Student at Carnegie-Mellon University, G.K. Sigworth, Formerly with Carnegie-Mellon University,     

Thermodynamic activity of Na2O in Na2O-CaO-SiO2, Na2O-MgO-SiO2, and Na2O-CaO-SiO2-Al2O3 melts at 1400°C

A gas phase equilibration technique was used to generate Na₂O isoactivity data at high-silica compositions in the systems Na₂O-CaO-SiO₂, Na₂O-MgO-SiO₂, and Na₂O-CaO-SiO₂-(10 and 20 wt pct) A1₂O₃ at 1400 °. Loga _{Na 2 O} values referenced to pure liquid Na₂O at 1400 ° as standard state ranged from about ?8.0 to ?7.0. Silica activities were calculated in the Na₂O-CaO-SiO₂ system using the Gibbs-Duhem equation. Richardson’s model for ideal mixing of basic oxides in silica was applied to the Na₂O-CaO-SiO₂ system. The model shows best fit when cationic mixing is assumed to occur on divalent sites. The alkali retention in slags has been described using a defined “sodium capacity”. The temperature variation of alkali retention was estimated, and the resulting sodium capacity was used to evaluate alkali stability in blast furnace slags.     

A mathematical model to predict the growth and elimination of inclusions in liquid steel stirred by natural convection

A model is developed to predict the rate of removal and the change in the size distribution of inclusions in a melt stirred by natural convection. Difficulties in obtaining an exact solution to the problem due to lack of adequate knowledge for the velocity fields in the melts are discussed. The model is based on Smoluchowski’s Theory of Gradient Collision to obtain the probability of collision between two inclusions under an arbitrarily chosen velocity gradient. Initial size distributions obtained in experimental heats are used as the input to the model. Various conditions are proposed by which inclusions are removed from the melt. The rates of removal are compared with the experimentally obtained rate of removal of oxides. It is observed that a boundary layer effect and the presence of a thin liquid metal film prevent rapid removal of inclusions from the stirred melts. Inclusion size distribution predicted by the model agrees qualitatively with the experimentally observed size distribution. It is postulated that the surface forces play a significant role in coalescence and assimilation of inclusions. Finally, the application of similar models to understand the removal of inclusions in such processes as argon sparging, solidification, degassing and electroslag remelting are advocated.