Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

A homologous series of 8-(4′-n-alkoxybenzoyloxy) quinolines were synthesized by established methods [5,6]. On evaluation by optical microscopy, none of the homologues were found to exhibit mesogenic behavior even in the monotropic condition. Then, each homologue (B) was mixed with a liquid crystal component (A) and binary systems were studied by optical microscopy. Solid–mesomorphic or isotropic–nematic transition temperatures of binary mixtures were determined and plotted to obtain the phase diagram for transition temperatures versus percentage composition of component (A). The nematic–isotropic transition curve was extrapolated to zero mole percentage of component (A) (100%B) to determine the latent transition temperature (LTT) of each nonmesomorphic homologue. The number of carbon atoms in the n-alkyl chain of each homologue versus LTT is plotted and a phase diagram is obtained. The isotropic–nematic transition curve behaves in a normal manner like a curve behaving for a typical nematogenic homologous ...

Determination of Latent Mesogenic Behavior in Nonmesogenic Compounds by Extrapolation Method

Three series of Schiff's base esters, 2‐hydroxy‐4‐methoxybenzylidene‐4′‐alkanoyloxyaniline, 2‐hydroxy‐3‐methoxybenzylidene‐4′‐alkanoyloxyaniline and 3‐methoxy‐4‐alkanoyloxybenzylidene‐4′‐alkanoyloxyaniline, which possess mono‐ and di‐substituted moieties at both ends of the molecules have been synthesized and their mesomorphic properties investigated along with physical characterization (elemental analysis, mass spectrometry, Fourier transform IR and high resolution NMR). The effect of lateral methoxy and polar hydroxy groups on the mesomorphism of the title compounds was studied, based on the thermal properties and textural analysis. The results indicate that compounds with the larger number of carbons in the alkyl chain prefer smectic phase formation and possess higher transition temperatures and molecular polarizability along the long axis. Further analysis shows that the greater shielding effect (through the formation of intramolecular interaction) leads to lower molecular broadening and results in hi...

Synthesis, physical and mesomorphic properties of Schiff's base esters containing ortho‐, meta‐ and para‐substituents in benzylidene‐4′‐alkanoyloxyanilines

In order to investigate the influence of the terminal substitution on mesomorphism, two new series of azo-Schiff base and azo-ester liquid crystals having the following structures have been synthesized. All the compounds possess mesomorphic properties. In series A compounds A1 and A3 exhibit only a nematic mesophase, whereas compounds A2, A4, A5, A6, A7, A8, A9, and A10 exhibit a smectic as well as a nematic phase. In series B compounds B1 to B9 exhibit only a nematic mesophase, and compounds B10 and B11 exhibit a smectic as well as a nematic phase, but compound B12 exhibits only a smectic phase. All these compounds were characterized by elemental analyses and spectroscopic techniques (Fourier transform infrared [FTIR], 1H nuclear magnetic resonance [NMR], and mass spectroscopy). Their mesomorphic properties were measured by optical polarized light microscopy and differential scanning calorimetry (DSC).

Effects of Different Terminal Substituents on the Mesomorphic Behavior of Some Azo-Schiff Base and Azo-Ester-Based Liquid Crystals

Four new groups of 4-((2ʹ-substitutedphenylimino)methyl)phenyl-4”-alkoxy benzoates, Ina-d, of Schiff base ester liquid crystals, were prepared and investigated for their mesophase formation and stability. Each group constitutes four homologous series that differ from each other by the lateral attached polar group X in the ortho position for the imine mesogen at terminal benzene ring that alternatively changed from F, Br, NO2 and lateral benzene ring. Within each homologous series, the number (n) of carbons in the alkoxy chain varies between 6, 8, 10 and 12. Molecular structures of the prepared compounds were confirmed via elemental analysis, FT-IR, and 1H NMR spectroscopy. Mesomorphic properties were investigated by differential scanning calorimetry (DSC) and the phase identified by polarised light microscopy (PLM). A comparative study was made between the investigated compounds and their previously prepared laterally neat, 4-((4ʹ-phenylimino)methyl)phenyl-4”-alkoxy benzoates (IIn); the result rev...

Schiff base/ester liquid crystals with different lateral substituents: mesophase behaviour and DFT calculations

Azobenzene derivatives were among the first ten liquid crystalline compounds. But there have been no detailed investigations on azomesogens consisting of a heterocyclic moiety. Twelve different azo compounds have been condensed with nicotinic acid to evaluate the effect of variation of terminal group on the monosubstituted pyridine system. The relative thermal stabilities and the variation in the mesomorphic characteristics have also been studied.

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Azomesogens with a heterocyclic moiety

A number of binary systems have been investigated with p-n-dodecyloxybenzal-p-n-butoxyaniline—a mesomorphic component exhibiting both smectic and nematic phases—and other non-liquid crystalline solutes. When the transition temperatures of such binary systems are plotted against the mole per cent composition of the liquid crystalline component, two types of curve are obtained: (1) A usual curve where the transition lines are depressed regularly and (2) a rising curve exhibiting only a smectic phase and a maximum. The latter type of curve indicates an enhancement in the smectic thermal stability while the former shows a decrease in the mesomorphic thermal stability during the course of mixed liquid crystal formation; the range of temperature over which the nematic phase exists increases at the cost of the smectic mesophase. It is observed that in such a binary mixture, if at least the first few compositions chosen melt to give the isotropic liquid at a temperature higher than the mesomorphic-isotro...

Mixed Mesomorphism in Binary Systems Forming Smectic-Nematic Phases

Two homologous series of liquid crystalline Schif base esters of the following structural formula are synthesized by condensing p)p′ -n-alkoxybenzoyloxy)benzaldehydes with p-anisidine and p-toluidine.

Mesomorphic Behaviour of Schiff Base Esters-I: (a) p(p′-n-Alkoxybenzoyloxy)benzylidene-p” -anisidines (b)p(p′ -n-Alkoxybenzoyloxy)benzylidene-p” -toluidines

Three new homologous series of liquid crystals with terminal fluoro group and central linkages such as ester and azo groups were synthesized and their mesomorphic properties were studied All three series are similar in molecular structure with the difference in their lateral substitutions: series I has no lateral substitution, series II has a chloro group as lateral substitution, and series III has a methyl group as lateral substitution All 12 homologues of each of the series are mesogenic in nature The nematic phase of the series shows a marble texture and the smectic phase shows a Schlieren texture of the smectic C variety The mesomorphic characteristics of the series are compared with each other

Effect of Lateral Substitution on Mesogenic Properties of Fluoro Aniline Derivatives

Thirteen p-n-alkoxybenzylidene-p-aminobenzoic acids were prepared and their mesomorphic transition temperatures were determined. They exhibit mesophases of greater relative thermal stability than the p-n-alkoxybenzoic and p-n-alkoxycinnamic acids but 4′-n-alkoxydiphenyl-4-carboxylic acids exhibit greater thermal stability than the acids studied here though p-n-alkoxybenzylidene-p-aminobenzoic acids are longer by -CH+N- group in the monomer; this may be attributed to the stereochemistry of -CH+N- link causing the molecule to be broader than the 4′-n-alkoxydiphenyl-4-carboxylic acids. Comparatively higher thermal stability of mesophases of these acids is emphasized by the mesomorphic behaviour of methyl p-n-alkoxybenzylidene-p-aminobenzoates which are purely smectic and the absence of anisotropic melt in the analogous p-n-alkoxybenzoates.

Jayrang S. Dave

Papers

Azomesogens with a heterocyclic moiety

Mixed Mesomorphism in Binary Systems Forming Smectic-Nematic Phases

Mesomorphic Behaviour of Schiff Base Esters-I: (a) p(p′-n-Alkoxybenzoyloxy)benzylidene-p” -anisidines (b)p(p′ -n-Alkoxybenzoyloxy)benzylidene-p” -toluidines

Effect of Lateral Substitution on Mesogenic Properties of Fluoro Aniline Derivatives

Influence of Molecular Structure on Liquid Crystalline Properties and Phase Transitions in These Structures, Part II