First observation of a smectic A-cholesteric phase transition in a thermotropic liquid crystal consisting of a rigid-rod helical polysilane

A smectic A-cholesteric phase transition for a rigid-rod helical polymer, poly[n-decyl-(S)-2-methylbutylsilane] (PD2MBS), with a narrow molecular weight distribution, has been observed for the first time. Polarizing optical microscopy showed that the fan-shaped texture of the smectic A phase turned into the characteristic planar texture of the cholesteric phase upon heating. The positive CD band, which corresponds to the reflection band of the cholesteric phase, gradually decreased in intensity within a range 30°C below the transition temperature on cooling, while the peak maximum shifted towards shorter wavelengths. It was concluded that the system has a very wide temperature region over which the cholesteric-smectic A phase transition occurs and in which the cholesteric pitch varies with temperature.     

THE ESTIMATION OF PRIOR FROM FISHER INFORMATION

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Synthesis of RE Y zeolite for formulation of FCC catalyst and the catalytic performance in cracking of n-hexadecane

Research on Chemical Intermediates - This study presents the synthesis of rare earth-doped Y (RE Y) zeolite, its application in formulation of a fluid catalytic cracking (FCC) catalyst and the...     

Evaluation of thermal diffusion factor and diffusion coefficient from measurements on a trennschaukel

Measurements have been taken on a glass trennschaukel of eight tubes for the Ar-He system as a function of composition and with its hot and cold bulbs at 100°c and 0°c. For each mixture, several speeds for the mechanical push-pull motion of the gas which cover a wide enough range were tried. The results have been interpreted to determine the thermal diffusion factor α _T, in conventional fashion as well as on the basis of a theory characterizing the low speed operation, developed here. Four such different possibilities of α _t evaluation are discussed and values compared with the traditional ones obtained from the convection-free two-bulb apparatus. Lastly we discuss also in brief the prospect of estimating the diffusion coefficient as an important byproduct from measurements on trennschaukel runs.     

Facile extraction,processing and characterization of biorenewable sisal fibers for multifunctional applications

Synthetic fibers based materials have replaced most of the traditional metallic/ceramic materials for a number of applications owing to their enormous properties such as light weight, specific strength and modulus to name a few. Unfortunately, the traditional synthetic fibers are not desired from the health and environmental point of view. So, in this work, we have carried out the isolation, processing and characterization of cellulosic sisal fibers. These fibers were extracted for the first time by a simple and new unique mechanical extraction technique without affecting the quality of fibers. Subsequently these cellulosic sisal fibers were thoroughly characterized for their physicochemical, microstructure and mechanical properties. These fibers were then converted into fine textured sisal textile yarn made out of 3–6 sisal fibers in continuous operation and used for the preparation of new green materials. Different properties of fine textured sisal textile and the impact of sisal fine textile on the physical, microstructural, thermal and mechanical characteristics of the green materials were studied and discussed in detail.     

Neutral current effects in the parity violating nuclear force

The measurements of the ΔI = 1 part of the parity violating nuclear force when combined with information on neutral current couplings from neutrino scattering and pion production experiments allow an estimate of the isoscalar admixture in the neutral current if it has a vector axial-vector structure has been shown.     

A selective membrane electrode for lanthanum(III) ion based on a hexaaza macrocycle derivative as ionophore.

We have developed a highly La(III)-selective PVC membrane electrode based on a hexaaza macrocycle, 8,16-dimethyl-6,14-diphenyl-2,3,4:10,11,12-dipyridine-1,3,5,9,11,13-hexaazacyclohexadeca-3,5,8,11,13,16-hexaene [Bzo2Me2Pyo2(16)-hexaeneN6] (I) as membrane carrier, dibutylbutyl phosphonate (DBBP) as solvent mediator and sodium tetraphenylborate (NaTPB) as lipophilic additive. The best performance was given by the membrane of macrocycle I having a composition 10:260:5:120 (I:DBBP:NaTPB:PVC). The electrode exhibits a Nernstian response to La(III) ion in the concentration range 1.0x10(-1)-7.94x10(-7) M with a slope of 19.8+/-0.2 mV/decade of concentration and a detection limit of 5.62x10(-7) M. The response time of the sensor is 12 s and it can be used over a period of 4 months with good reproducibility. The electrode works well over a pH range of 2.5-10.0 and in partially non-aqueous medium with up to 30% organic content. The sensor was also used as an indicator electrode in potentiometric titration of La(III) ions with EDTA and for determining La(III) concentration in real samples.     

The Cavity Method for the Rigidity Transition

In order to motivate an analogy between the rigidity theory and combinatorial optimization, we have used the cavity method to study the floppy to rigid transition in a 2-dimensional (2D) random graph as well as in a 3D small world chain. Our analytic results are in excellent agreement with numerical studies using the pebble game algorithm. We also illustrate that a transfer matrix method is equivalent to the cavity method at the replica symmetric level