Calibration of migration times of variable salinity samples with internal standards in capillary electrophoresis

A practical approach is presented for identifying the analyte peaks stacked by transient ITP (TITP) in samples of uncontrolled salinity. For TITP with chloride ions acting as the leading electrolyte, the effect of matrix chloride of an unknown concentration was calibrated using multiple internal standards to predict the migration times of weakly acidic anionic analytes behaving as strong electrolytes to an accuracy of over 99.9%. The calibration equations for the migration time of an analyte are given as a function of the migration times of internal standards using the mobilities of the relevant ions as parameters. The effects of matrix chloride and various separation conditions such as the temperature, plug length, ionic strength, and pH of the BGE were completely eliminated from the calibration equations. In addition, the actual mobilities, determined for a standard saline sample under the working conditions, were used, and thus, there was no need to conduct supplementary experiments to determine the absolute mobilities at infinite dilution. The internal standards were dyes, which were easily identified in an auxiliary channel monitoring the absorbance at a longer wavelength. For five standard saline matrices containing 100-300 mM NaCl at intervals of 50 mM, the mean absolute error (MAE) in migration times calibrated with two internal standards was 0.4 s (n=5x13). For an electropherogram of a real standard reference urine sample, peaks of spiked analytes were identified with an MAE of 0.9 s (n=13) without conductivity normalizing or desalting of the sample.     

Cache Oblivious Algorithms for the RMQ and the RMSQ Problems

In the Range Minimum/Maximum Query (RMQ) and Range Maximum-Sum Segment Query (RMSQ) problems, we are given an array which we can preprocess in order to answer subsequent queries. In the RMQ query, we are given a range on the array and we need to find the maximum/minimum element within that range. On the other hand, in RMSQ query, we need to return the segment within the given query range that gives the maximum sum. In this paper, we present cache oblivious optimal algorithms for both of the above problems. In particular, for both the problems, we have presented linear time data structures having optimal cache miss. The data structures can answer the corresponding queries in constant time with constant cache miss.     

Gamma radiolytic degradation of the endrin insecticide in methanol and monitoring of radiolytic degradation products by HPLC

The objective of this investigation was to verify the degradation of endrin by gamma irradiation. ⁶⁰Co was used as radiation source for irradiation of 50 mg L^?1 endrin with a varied dose of 1–6 kGy. High performance liquid chromatography (HPLC) coupled with diode array detector was used as an analytical technique to monitor the degradation rate along with numbers of degradation products formed. At dose rate of 6 kGy ≥99% of endrin was degraded. It is proposed that utilization of ionization radiations can be an effective and efficient tool for the removal of halogenated pesticides.     

On the numerical integration of a boundary value problem involving a fourth order linear differential equation

A finite difference method for the numerical integration of the linear two-point boundary value problem $$y^{(4)} + f(x)y = g(x),y(a) = A_1 ,y(b) = A_2 ,y''(a) = B_1 ,y''(b) = B_2$$ is constructed and analyzed. The method usesf′,f″,g′,g″ at the boundary points to obtain anO(h ⁶) global error, while requiring only the solution of a system of linear equations associated with a five-band matrix. A typical numerical example is included to demonstrate the practical usefulness of the numerical procedure as well.     

Interactive Sequential Goal Programming

This paper introduces a new solution method based on Goal Programming for Multiple Objective Decision Making (MODM) problems. The method, called Interactive Sequential Goal Programming (ISGP), combines and extends the attractive features of both Goal Programming and interactive solution approaches for MODM problems. ISGP is applicable to both linear and non-linear problems. It uses existing single objective optimization techniques and, hence, available computer codes utilizing these techniques can be adapted for use in ISGP. The non-dominance of the "best-compromise" solution is assured. The information required from the decision maker in each iteration is simple. The proposed method is illustrated by solving a nutrition problem.     

Effect of pH on the adsorption of Ce3+, Sm3+, Eu3+ and Gd3+ ions on activated charcoal

The adsorption of metal ions such as Ce³⁺, Sm³⁺, Eu³⁺ and Gd³⁺ ions on activated charcoal has been studied as a function of pH. The adsorption mechanism of these ions is discussed in terms of hydrolyzed species formed in aqueous solution at different pH.     

Determination of lanthanides in uranium solutions by X-ray fluorescence spectrometry

An XRF-method for the determination of Sm, Gd, Dy, Er and Eu in uranium solution by use of simple polyethylene bottles has been established. Spectral interferences and matrix effects like absorption enhancement have been rectified using standards of similar composition in the absence of internal standard. Analytical application of the method used has been established on the basis of statistical evaluation.     

Pattern formation induced by additive noise: a moment-based analysis

We analyze the condition for instability and pattern formation induced by additive noise in spatially extended systems. The approach is based on consideration of higher moments which extract out nonlinearities of appropriate order. Our analysis reveals that cubic nonlinearity plays a crucial role for the additive noise to a leading order that determines the instability threshold which is corroborated by numerical simulation in two specific reaction-diffusion systems.     

Some new consistency relations connecting spline values and integrals of the spline

This paper is concerned with polynomial splines on a uniform mesh. Linear dependence relations connecting spline values (or derivatives) and integral values of the spline are developed.     

Smooth spline approximations for the solution of a boundary value problem with engineering applications

Methods of order 2, and 4 are developed for the continuous approximation of the solution of a two-point boundary value problem involving a fourth order linear differential equation via quintic and sextic spline functions. In three typical numerical examples, the results are briefly summarized to demonstrate the practical usefulness of the methods.