USE OF A pH-STAT DILUTION TO DETERMINE CRITICAL MICELLE CONCENTRATIONS AND COUNTERION CONCENTRATIONS OF IONIC MICELLES1

The use of a pH-stat to determine the critical micelle concentration (c.m.c.) of ionic micellar solutions is described. Counterion is released with the dilution of an ionic micellar solution at all concentrations above the c.m.c. The titration of the released counterion permits the evaluation of the c.m.c. and the associated amount of counterion for any concentration above the c.m.c. The diluent is the same medium in which the micelle is dissolved. Thus any ionic strength, ion composition, or pH may be used. Examples of the method to determine the c.m.c. of promethazine hydrochloride in water and of tetracaine hydrochloride in 0.128 N NaCl as a function of pH are given. Also the c.m.c of promethazine hydrochloride - Tween 80 mixtures was examined as a function of mole fraction.     

Calcium(II)-selective potentiometric sensor based on p -isopropylcalix6arene in PVC matrix

In Japan, large amounts of fertilizer nitrogen are applied to tea plantations. We collected samples of tea plantation soil each season for a year. Samples were analyzed for their contents of various inorganic chemicals and total N. Nitrogen was present mainly in the top 0 to 30?cm of soil. However, at times the concentration of nitrate N in the soil water was more than 35?mg?L^?1, even in the deepest layers. The contents of various metal elements in the soil were examined. Ba, Fe, Sr and Zn contents were high in the top 0 to 30?cm of soil. But Al and Mn contents were not always high in the top 0 to 30?cm of soil. From the correlation analysis among contents of various inorganic chemicals, it was suggested that increased leaching of Al, Mn, and Zn from tea plantation soil occurred with increased nitrate N concentration.     

Effect of heat treatment on thermal and mechanical stability of NaOH-doped xanthan gum-based hydrogels

Journal of Solid State Electrochemistry - Xanthan gum (XG)-based hydrogels containing sodium hydroxide (NaOH) salt were synthesized with the use of distilled water (DW) at room temperature and...     

Stability and dynamic analysis of partially cracked thin orthotropic microplates under thermal environment: an analytical approach

Abstract

An analytical model is proposed to analyze the vibration and buckling problem of partially cracked thin orthotropic microplate in the presence of thermal environment. The differential governing equation for the cracked plate is derived using the classical plate theory in conjunction with the strain gradient theory of elasticity. The crack is modeled using appropriate crack compliance coefficients based on the simplified line spring model. The influence of thermal environment is incorporated in governing equation in form thermal moments and in-plane compressive forces. The governing equation for cracked plate has been solved analytically to get fundamental frequency and central deflection of plate. To demonstrate the accuracy of the present model, few comparison studies are carried out with the published literature. The stability and dynamic characteristics of the cracked plate are studied considering various parameters such as crack length, plate thickness, change in temperature, and internal length scale of microstructure. It has been concluded that the frequency and deflection are affected by crack length, temperature, and internal length scale of microstructure. Furthermore, to study the buckling behavior of cracked plate, the classical relations for critical buckling load and critical buckling temperature is also proposed considering the effect of crack length, temperature, and internal length scale of microstructure.     

Finite element Galerkin Approach for a Computational Study of Arterial Flow

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