Refractive index profiling-state of the art

Problems associated with different calibration techniques and some instrumental effects that can determine instrumental accuracy are discussed. It is shown how transmission effects can be observed and used to generate a correction curve for refracted near-field instruments. High-quality fiber slices needed for axial interferometry were used to obtain refractive index differences on suitable fibers to ±1% with the measurements traceable to national standards. Interferometry was used to calibrate a multiple-step fiber which is available in 10-m lengths with a certificate of calibration. The limitations of the technique are discussed, and preliminary results of a study on the effects of residual stress and stress relief on measurements are given. Comparisons are made between measurements made by axial interferometry and refracted near field on a range of fibers. It is shown that commercial profilers can produce reliable measurements of refractive index difference, absolute refractive index, profile shape, and numerical aperture that agree well with measurements by other techniques     

Influence of Al and Ni concentration on the Martensitic transformation in Cu-Al-Ni shape-memory alloys

The martensitic transformation temperatures and the types of martensitic phases have been determined in a wide concentration range of technological interest for Cu-Al-Ni shape-memory alloys (SMAs) A stability diagram of martensitic phases as a function of alloy concentration has been determined. It is found that when the aluminum content increases, the transformation changes from β ₃ ⇒ β′₃ to β ₃ ⇒ γ′₃, with an intermediate concentration range where both martensites coexist due to a β ₃ ⇒ γ′₃+β′₃ transformation. On the other hand, an increase of nickel content stabilizes the martensite β′₃, changing from a mixed β ₃ ⇒ γ′₃ + β′₃ to a single β ₃ ⇒ β′₃ transformation. Furthermore, linear relationships between M _s and Al and Ni concentrations have been obtained for all types of martensitic phases.     

Analysis of a TEM Cell with Septum on a Dielectric Slab

A quasi-TEM approach based on conformal transformation is used for the determination of the characteristic impedance of a rectangular coaxial line (TEM cell) having a symmetrically located inner conductor (septum) supported on a dielectric slab of equal width. The method of determination of the capacitance of the dielectric-filled portion is discussed. The results on characteristic impedance for two values of dielectric constant are presented.     

Crystallization and agglomeration kinetics of nickel ammonium sulphate in an MSMPR crystallizer

Precipitation of nickel ammonium sulphate achieved by mixing solutions of nickel sulphate and ammonium sulphate in a 5 1 MSMPR crystallizer is used to investigate both crystallization and agglomeration kinetics from the steady-state crystal size distribution. An iterative non-linear parameter estimation procedure is used to deduce the kinetic rate parameters in the solution of the agglomeration model suggested by Liao and Hulburt from the data-set obtained by size analysis of the product crystals. The results obtained are correlated in terms of conventional power law kinetic expressions.     

DRYING OF GRANULAR PARTICLES IN A MULTISTAGE INCLINED FLUIDIZED BED WITH MECHANICAL VIBRATION

A mathematical model for the drying rate of granular particles in a multistage inclined fluidized bed(IFB) is presented from the standpoint of simultaneous heat and mass transfer, with taking the effect of mechanical vibration added vertically into consideration.

Steady-state distributions for the temperatures and concentrations of the particles and the heating gas, and for the moisture content of the particles are numerically calculated based on the present model. The calculated results show fairly good agreement with the experimental data, which were obtained from the drying experiments of brick particles in a three-stage IFB using comparatively low temperature air(40-60°C) as the heating gas.

It has been found within the range of the experimental conditions employed that, the mechanical vibration added vertically enhances the over-all drying rate of the particles and its effect can be considered equivalent to an increase in the air velocity.     

CAFTURE AND RECYCLE OF BYPASSING BUBBLE GAS IN A FLUIDIZED BED: THE “BUBBLE EATER”

The bubble eater is a device which can sense, capture, and recycle bubble gas in a bubbling fluidized bed. The theory describing the enhancement of reactant gas conversion are presented and illustrated by means of a numerical example.     

Further studies on elastic-plastic stable fracture utilizing the T integral

Herein, the T^* fracture parameter is shown to have relevance to the mechanics of elastic-plastic fracture. Specifically, it is shown to have certain advantages over the currently established plastic fracture parameters such as J and CTOA. Finite element analyses of experimental data were carried out as a means to obtain a comparison of the effectiveness of the plastic fracture parameters. T^* is clearly superior. A note on problems associated with satisfying the plastic incompressibility constraint is also included.