Novel method for determination of sodium in foods by thermometric endpoint titrimetry (TET)

A novel yet simple, rapid and robust thermometric endpoint titration (TET) method for the determination of sodium in various foodstuffs is described. Sodium reacts exothermically with aluminium in the presence of an excess of potassium and fluoride ions to form NaK2AlF6 (“elpasolite”). This reaction forms the basis of a ro- bust, reliable analytical procedure suitable for routine process control. The reaction of calcium under similar conditions (to form KCaAlF6) suggests that potentially, calcium may interfere in the determination of sodium in some foodstuffs. Results of an investigation suggest that at molar ratios [Ca]/[Na] < 0.85, an error of <1% of the measured value of sodium is incurred.

Corrosion Studies on Stainless Steel (FE6956) in Hydrochloric Acid Solution

The effect of hydrochloric acid concentration on stainless steel (Fe6956) at temperature range 303 - 333 ± 1 K has been studied using weight loss, thermometric and electrochemical polarization techniques. The corrosion rate of the stainless steel was found to be dependent on both temperature variation and acid concentration. The potentiostatic study showed that the active passive transition depends strongly on acid concentration while the weight loss measurements revealed that 2 M HCl at temperature 333 K had an appreciable corrosion rate which corresponds to 14.04 × 10﹣3 reaction number (RN) got from thermometric monitoring. Arrhenius equation and transition state theory were used to calculate kinetic and thermodynamic parameter such as Ea, ΔH* and ΔS*. Results obtained showed that corrosion reaction of Fe6956 in HCl is spontaneous and there is good agreement between the data got from the techniques employed.

Applied Energy

Most of the existing building stock has a deficient energy behaviour.The thermal transmittance of fa c,ades is among those aspects which most affect this situation.In this paper,the calculation procedure with correction for storage effects from ISO 9869-1 was applied to the thermometric method to determine the U-value.Due to the need for determining the number and type of layers that compose the wall to apply the calculation,a multilayer perceptron has been developed to estimate the U-value.From the different model configurations suggested,the most adequate architecture was the one with 14 nodes in the hidden layer without making transformations in the input variables.Valid results have been obtained by the multilayer perceptron for the case studies analysed from different building periods,with deviations lower than 20%between the measured value and the expected one,varying the test duration according to the thermal resistance of the wall and the temperature variations.Furthermore,it is not necessary to carry out a data post-processing for the model,so this fact simplifies and hastens the calculation procedure.

The measuring of spectral emissivity of object using chaotic optimal algorithm

There exist a considerable variety of factors affecting the spectral emissivity of an object. The authors have designed an improved combined neural network emissivity model, which can identify the continuous spectral emissivity and true temperature of any object only based on the measured brightness temperature data. In order to improve the accuracy of approximate calculations, the local minimum problem in the algorithm must be solved. Therefore, the authors design an optimal algorithm, i.e. a hybrid chaotic optimal algorithm, in which the chaos is used to roughly seek for the parameters involved in the model, and then a second seek for them is performed using the steepest descent. The modelling of emissivity settles the problems in assumptive models in multi-spectral theory.

Thermometric properties of Na_(2)Y_(2)TeB_(2)O_(10):Tb^(3+)green phosphor based on fluorescence/excitation intensity ratio

For noncontact optical thermometry,in contrast with fluorescence intensity ratio(FIR)technology,excitation intensity ratio(EIR)technology has been seriously limited due to low sensitivity.Moreover,by exploring all possible temperature-dependent response,developing multimode optical thermometry is of great importance.In this work,a new Na_(2)Y_(2)TeB_(2)O_(10):Tb^(3+)phosphor is obtained by a solid-state reaction.Based on FIR and EIR models of Tb',thermometric properties are studied thoroughly.Excellent relative and absolute sensitivity(S_(R)and S_(A))are acquired due to the significant difference in emission/excitation lines in response to temperature.Meanwhile,Tb^(3+)content-dependent luminescence quenching mechanism is discussed.This study shows a feasible route for exploiting well-performing FIR-/EIR-based thermometric materials.