A versatile preconcentration system for trace element determination by ICPMS was developed. It is composed of a commercial flow injection analysis system (FIAS) retrofitted with a home-made control unit containing three solenoid valves and working concomitantly with the FIAS, permitting selection and segmentation of sample, reagent, washing solution and elution flow. The knotted reactor used ha...

the acid-base equilibrium of lorazepam was studied by means of potentiometry andmultiwavelengths spectrophotometry. the stoichiometric equilibrium constants were determinedat 25 °c and constant ionic strength 0.1 mol l-1 (nacl). the acidity constants pk1=1.58±0.05and pk2=11.67±0.07 were found by potentiometry, and pk1=1.54±0.02 and pk2=11.61±0.03 bymulti-wavelengths spectrophotometry. potentiom...

background: tea is the most popular nonalcoholic beverage worldwide. in recent years, some iranian studies have shown the occurrence of toxic elements in fresh or dried tealeaves as well as in brewed tea. the present study aimed to ascertain the health risks associated with exposure to toxic and essential element through black tea consumption in iran by systematically reviewing the accredited a...

We have studied the contents of trace elements of nutritional or toxicological interest in 90 samples of whole, low-fat, skim, condensed, evaporated and powdered milks. Slurries of the samples were prepared with Triton X-100 and analysed using electrothermal atomic absorption spectrometry. The temperature-time programme of the graphite oven was optimized for each element, and the accuracy, prec...

In the hp-adaptive version of the finite element method for solving partial differential equations, the grid is adaptively refined in both h, the size of the elements, and p, the degree of the piecewise polynomial approximation over the element. The selection of which elements to refine is determined by a local a posteriori error indicator, and is well established. But the determination of whet...

to achieve an excellent thermal-mechanical performance of cmcs, it is necessary to analyze and design the thickness of the multi-layered interphases for an optimized trs distribution. an optimization was performed with a new version of the particle swarm optimization, the bsg-starcraft radius pso linked to a finite element software.

Maximum likelihood predictive densities (MLPD) for the inverse Gaussian distribution are derived for the cases of one or both parameters unknown. They are then applied to obtain estimators of the reliability function and prediction or shortest prediction intervals for a future observation. Comparisons with the existing likelihood or frequentist methods show that the MLPD estimators of reliabili...

Pasture biomass is an important quantity globally in livestock industries, carbon balances, and bushfire management. Quantitative estimates of pasture biomass or total standing dry matter (TSDM) at the field scale are much desired by land managers for land-resource management, forage budgeting, and conservation purposes. Estimates from optical satellite imagery alone tend to saturate in the cov...