Crystal agglomeration of europium oxalate in reaction crystallization using double-jet semi-batch reactor

The particle agglomeration of europium oxalate was investigated in a double-jet semi-batch reactor over a wide range of operating variables, including the agitation speed, reactant feed rate, and reactant concentration. The size of the agglomerates was directly dictated by the particle collision and supersaturation promoting agglomeration and the fluid shear force inhibiting agglomeration. Thus, with a longer feeding time and higher feed concentration for the reaction crystallization, the mean particle size increased, while the corresponding total particle population decreased due to the enhanced chance of particle agglomeration, resulting from a longer residence time and higher supersaturation in the reactor. Agitation was found to exhibit a rather complicated influence on particle agglomeration. Although both particle collision and turbulent fluid shear were promoted by an increase in the mixing intensity, the crystal agglomeration of europium oxalate was maximized at around 500 rpm of agitation speed due to an optimized balance between particle aggregation and breakage.     

Estimation of distribution function and distribution parameter from incomplete data

In this paper, in order to estimate the distribution parameter from incomplete data, a method based on Marquardt's least squares method used to estimate nonlinear parameters is proposed. Using the Euclid distance and the principle of nearness of fuzzy set theory, the hypothesis concerning the distribution function of a parent population is tested in the incomplete data case.     

Sample size required to estimate a parameter in the power function distribution

The purpose of this paper is to establish a two step sampling procedure for estimating the parameter θ of the power function distribution to within givend units of its true value with a given probability 1—α;(0<α<1). The density of the power function distribution is a function of two parameters, the second of whichk is assumed known. Given a preliminary sample sizem, tables and formulas are presented by which one may establish the sizen of the second sample such thatP(|y _n —θ|<d)>1—α is true, wherey _n is the largest observation in the second sample. The method used is deriving the results of this paper is similar to that given by Graybill and Connell (1964) and since the power function density reduces to the uniform density whenk=0, their results can be derived from the formulas given here. Also a table of comparisons between the expected second sample size in this paper and two other solutions is given.

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Sumario El propósito de este escrito es el de establecer un procedimiento de muestreo de dos pasos, para estimar el parámetro de la distribución de funciones de potencia cerca ded unidades de su valor verdadero con una probabilidad 1—α;(0<0<α<1). la densidad de la distribución de funciones de potencia es una función de dos parámetros, el segundo de los cualesk se supone es conocido. Dado un tama?o de muestra preliminarm, se presentan tabulaciones y fórmulas con las cuales se puede establecer el tama?on de la segunda muestra, de tal manera queP(|y _n —θ|<d)>1—α sea cierto, dondey _n es la observación más grande en la segunda muestra. El método usado en la derivación de los resultados de este escrito es similar al dado por Graybill y Connell (1964, Journal of the American Statistical Association) y ya que la densidad de funciones de potencia se reduce a la densidad uniforme cuandok=0, sus resultados pueden ser derivados a partir de las fórmulas dadas aquí. Además, se presenta una tabulación de comparaciones entre el segundo tama?o de muestra dado en este escrito y otras dos soluciones. Lafdp de la distribución de funciones de potencia es de la formaf(u)=(k+1)θ ^−(k+1) u ^k ,0<u<θ, θ>0 y cero en cualquiera otra parte.

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Research supported under ONR contract N00014-68-A-0515.     

Native protein proteolysis in an immobilized enzyme reactor as a function of temperature

Trypsin concentration and the unmasking of cleavage sites in proteins play important roles in the stoichiometry of peptide production and the number of limit peptides generated during proteolysis. The hypothesis explored in this work was that native proteins could be digested and identified without disulfide reduction by (i) enhancing the unmasking of cleavage sites through elevated reaction temperatures and (ii) increasing trypsin concentration by use of an immobilized enzyme reactor (IMER). Transferrin was chosen as a model protein for these studies on the basis of its resistance to trypsin digestion. Results from this study showed greater than 70% sequence coverage in the peptides identified when nonreduced transferrin was digested at 60 °C. Large numbers of missed cleavages were observed from specific regions in proteins. Proteolysis appeared to start at a small number of high frequency cleavage sites in the cases of both reduced and nonreduced transferrin. Although approximately the same number of peptides were obtained from both structural forms of transferrin, the location of high frequency cleavage sites and the peptides produced were very different. Results from this study suggest that the location of initial cleavage sites along with the path of subsequent digestion depends strongly on the type of treatment used to open protein structures up for proteolysis.     

The degradation of selected-area channelling patterns as a function of glide anisotropy

The study of selected-area channelling pattern (SACP) degradation with deformation was performed using lines representing different sets of planes. It was established that the degradation of different lines on the SACP taken after a given deformation was not the same. It differs not only for lines from different sets of planes but also within the same type of line. The amount of relative line broadening depends on the position of a given plane with respect to the glide plane and direction. It tends toward a maximum for SACP lines from those planes perpendicular to the Burgers vector and a minimum for those parallel to that vector. It is proposed that at the beginning of the deformation process, while only. a few systems operate, this phenomenon is most pronounced because of glide anisotropy.     

Equilibrium studies on hydrolysis of urea in a semi-batch reactor for production of ammonia to reduce hazardous pollutants from flue gases

The increasing environmental awareness and the mandate of the pollution control agencies in various part of country for lowering emission of air pollutants such as CO(2), NO(x), SO(2) and fly ash emissions, has increased the urgency for reviewing options and alternatives to accomplish the above objective. The addition of ammonia into the flue gas stream as a conditioning agent is found to be used in recent years for the reduction of air pollutants. Flue gas conditioning requires in situ generation of ammonia as the transportation and storage of anhydrous ammonia is hazardous in nature. The equilibrium study on hydrolysis of urea was done in a semi-batch glass reactor to investigate the effect of reaction temperature, initial feed concentration and stirring speed on ammonia production. Few experiments were carried out in a semi-batch reactor at atmospheric pressure by using different concentration of urea solution from 10 to 40 wt% of urea to water and equilibrium study has been done. The study reveals that conversion increases exponentially with an increase in temperature but the conversion decreases with increase in the inlet feed concentration of urea solution. Furthermore, the effect of stirring speed on conversion has also been studied and it found that conversion increases with increase in stirring speed.     

Enhanced degradation of p-chlorophenol in a novel pulsed high voltage discharge reactor

The yields of active specie such as ozone, hydrogen peroxide and hydroxyl radical were all enhanced in a novel discharge reactor. In the reactor, the original formation rate of hydroxyl radical was 2.27 x 10(-7) mol L(-1)s(-1), which was about three times than that in the contrast reactor. Ozone was formed in gas-phase and was transferred into the liquid. The characteristic of mass transfer was better in the novel reactor than that in the contrast reactor, which caused much higher ozone concentration in liquid. The dissociation of hydrogen peroxide was more evident in the former, which promoted the formations of hydroxyl radical. The p-chlorophenol (4-CP) degradation was also enhanced. Most of the ozone transferred into the liquid and hydrogen peroxide generated by discharge could be utilized by the degradation process of 4-CP. About 97% 4-CP was removed in 36 min discharge in the novel reactor. Organic acids such as formic, acetic, oxalic, propanoic and maleic acid were generated and free chloride ions were released in the degradation process. With the formation of organic acid, the pH was decreased and the conductivity was increased.     

Reliability and true-score measures of binary items as a function of their Rasch difficulty parameter

This article provides formulas for expected true-score measures and reliability of binary items as a function of their Rasch difficulty when the trait (ability) distribution is normal or logistic. The proposed formulas have theoretical value and can be useful in test development, score analysis, and simulation studies. Once the items are calibrated with the dichotomous Rasch model, one can estimate (without further data collection) the expected values for true-score measures (e.g., domain score, true score variance, and error variance for the number-right score) and reliability for both norm-referenced and criterion-referenced interpretations. Thus, given a bank of Rasch calibrated items, one can develop a test with desirable values of population true-score measures and reliability or compare such measures for subsets of items that are grouped by substantive characteristics (e.g., content areas or strands of learning outcomes). An illustrative example for using the proposed formulas is also provided.     

Ozonation of acid yellow 17 dye in a semi-batch bubble column

A semi-batch bubble column was used to evaluate the effect of ozonation on the removal of acid yellow 17 dye from water. Results indicate that ozonation is very effective at removing acid yellow 17 dye from synthetic textile wastewater. The ozone consumed to apparent dye removal ratio ranged from 2 to 15,000 mg ozone per mg of dye decolorized and was dependent on both ozonation time and apparent dye concentration. The biodegradability of the dye wastewater was evaluated by monitoring changes in 5-day biochemical oxygen demand (BOD5) with respect to chemical oxygen demand (COD). Results indicate that the wastewater biodegradability increased with an increase in ozonation time. Film theory was used to kinetically model the gas-liquid reactions occurring in the reactor. Modeling results indicated that during the first 10-15 min of ozonation, the system could be characterized by a fast, pseudo-first-order regime. With continued ozonation, system kinetics transitioned through a moderate then to a slow regime. Successful modeling of this period required use of a kinetic equation corresponding to a more inclusive condition. Model results are presented.     

Control charts for the shape parameter of reflected power function distribution under classical estimators

The reflected power function distribution (RPFD) has applications in the fields of reliability engineering and survival analysis. To identify and remove the variation in different reliability processes and also to monitor the reliability of machines where the number of errors follows RPFD, we develop control charts to keep the process in control. A memory less control chart like a Shewhart control chart, and two memory-based control charts like an exponentially weighted moving average (EWMA) control chart and a hybrid exponentially weighted moving average (HEWMA) control chart are discussed and compared with each other. Proposal of these control charts is based on two different estimators, the percentile estimator (PE) and the modified maximum likelihood estimator (MMLE). This study shows that an HEWMA control chart based on PE performs better than PE-based Shewhart and EWMA control charts, as well as MMLE-based Shewhart, EWMA, and HEWMA control charts.     

Control function margin degradation in a bubble memory chip

Chip control function and propagation circuit margin degradation due to long-term memory operation, was observed, using the bias field switching technique. 16 kbit major-minor loop organized bubble memory chips with 28 μm bit period, which had an average access time of 2.7 ms for a 100-kHz rotating field, were used. It was seen that degradations in the lower side of the bias field range were independent of chip functional elements. However, at the upper side of the bias field range, degradations in the performance can be classified by dividing the elements into two categories. These were propagation circuits (Permalloy patterns only) such as H-bars, chevrons, etc., and control functions (Permalloy and conductor patterns), such as generators, replicators, etc. Also, it was found that the degradation in the performance of propagation circuits is small compared with that of the control functions. These differences were considered to be caused by a failure in the Permalloy steps over conductors and/or by the magnetic interaction of the bubble and the conductor current.     

Nonisothermal polymerization in a spherical reactor. Temperature distribution and reaction kinetics

The possibility of solving the converse thermal conductivity problem beginning with temperature measurements during the process of nonisothermal polymerization is demonstrated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 4, pp. 636–641, April, 1978.     

Integrated low-carbon distribution system for the demand side of a product distribution supply chain: a DoE-guided MOPSO optimiser-based solution approach

This article contributes to distribution system literature on three inter-linked aspects viz. formulation of a novel integrated low-carbon/green distribution system for the demand side of a Supply Chain (SC) with a single product and multiple consumers, i.e. drop-off points, a novel and robust solution approach through a Design of Experiment (DoE)-guided Multiple-Objective Particle Swarm Optimisation (MOPSO) optimiser and exhaustive analysis of the solutions (i.e. prioritisation, ranking and scenario analysis). The total costs, CO₂ emission and the traversed distances of the vehicles during transportation are optimised. The optimisation model for the strategic decision-making is formulated by effectively integrating the 0–1 mixed-integer programming with a green constraint based on Analytic Hierarchy Process. Due to the computationally NP-hard characteristic of the model, a systematic and technically robust DoE-guided solution approach is designed using a commercial solver – modeFRONTIER^®. DoE guides the solution through the MOPSO optimiser in order to eliminate the un-realistic set of feasible and optimal solution sets. A popular multi-attribute decision-making approach, TOPSIS, evaluates the solutions found from the Pareto optimal solution space of the solver. Finally, decision-makers’ preferences are analysed for monitoring the changes in the controlling parameters with respect to the changes in the decisions. A scenario analysis of the events by considering alternative possible outcomes is also conducted. It is found that the implemented methodology successfully routes the vehicles with optimal costs and low-carbon emission thus contributing to greening the environment on the demand side of a SC network.     

Exit distribution function crossover in a Galton board

Here we present an experimental and numerical study concerning the problem of the influence of walls on a granular flow through obstacles. The system based on a Galton Board is a vertical bi-dimensional array of equally spaced obstacles arranged to form a triangular lattice. Lateral walls, whose relative separation can be varied, are set. Disks of equal diameters are launched at the top of the system. During the fall, the disks collide inelastically with the obstacles of the lattice and, eventually, with lateral walls. At the exit, at the bottom of the board, disks are collected in separate bins depending on their final horizontal positions. The aim of the present paper is to study the dependence of the exit distributions of small disks on the separation between the lateral walls of the board. We found that there exists a crossover from a Gaussian-like to a uniform-like behaviour when the separation between walls is less than a critical value. A systematic study of this crossover is performed through numerical simulations and the results are also approximated by a theoretical model of the problem.     

Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: parameter study and reaction pathways

The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO(2)) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO(2) dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO(2)/UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (E(EO)=71 kWh/(m(3)order)) was obtained in TiO(2)/UV process. To obtain a better understanding of the mechanistic details of this TiO(2)-assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed.     

Model of a measurement error distribution function

Translated from Izmeritel'naya Tekhnika, No. 8, pp. 6–9, August, 1989.     

Hydrothermal synthesis of sphere-like BiOCl using sodium lignosulphonate as surfactant and its application in visible light photocatalytic degradation of rodamine B

The BiOCl-SL was prepared by a simple hydrothermal reaction between Bi(NO₃)₃·5H₂O and KCl using sodium lignosulfonate (SL) as a structure-directing agent. The standard tetragonal structure of the BiOCl has been confirmed by X-ray powder diffraction. The scanning electron microscopy results revealed that a suitable amount of SL is favorable for the formation of hollow sphere-Like BiOCl. The fourier transform infrared spectroscopy (FT-IR) of the BiOCl-SL showed the BiOCl samples have been cleaned thoroughly, and the following photocatalytic experiment will not be affected by SL. In comparison with the pure BiOCl, the UV–Vis diffuse reflectance spectroscopy (UV–Vis-DRS) of the BiOCl-SL showed a red shift of absorption edge. The Brunauer–Emmett–Teller surface area measurement indicated that the surface area of BiOCl-SL is much bigger than that of pure BiOCl. The photocatalytic activity of BiOCl was tested on the degradation of Rodamine B (RhB) under visible light irradiation, and the result showed that the BiOCl-SL-0.3 had excellent photocatalytic activity for RhB after visible light irradiation for 2 h.