Elasticity solution for a long circular sandwich cylindrical shell subjected to axisymmetric load

An elasticity solution has been obtained for a long circular sandwich cylindrical shell subjected to axisymmetric radial ring load using Love's stress function approach. Numerical results are presented for different ratios of modulus of elasticity of the layers. The results obtained from this analysis have been compared with those obtained from sandwich shell theory due to Fulton.

Circular dichroism and nuclear magnetic resonance studies on the complexation of valinomycin with calcium

Complexation of valinomycin (VM) with the divalent cation Ca2+ in a lipophilic solvent, acetonitrile (CH3-CN), has been studied by using circular dichroism and proton and carbon- 13 nuclear magnetic resonance (‘H NMR and I3C NMR). From analyses of the spectral data, it is concluded that VM forms a 2:l (peptideion-peptide) sandwich complex with Ca2+, at low concentration of VM. At moderate conocentrations of the salt, in addition to the sandwich complex, an equimolar (1:l) complex different from those observed for potassium and sodium is also observed. At very large concentrations of the calcium salt, the data suggested a complex with a conformation similar to that of the free VM in polar solvents. Possible conformations for the sandwich and the equimolar VM-calcium complexes are proposed.

Bilirubin binding to polypeptides and chiral amines. Induced circular dichroism and fluorescence studies

Induced Cotton effects have been observed in the visible region on interaction of bilirubin with chiral mono- and diamines and poly-l-lysine. At alkaline pH distinct CD spectra are observed for bilirubin bound to the α-helical and β-sheet conformation of poly-l-lysine, which differ from that observed for the pigment bound to human serum albumin. The CD pattern observed on binding to N-acetyl-Lys-N1-methylamide in CH2Cl2 and dioxane is different from that observed in the presence of l-Ala-NH-(CH2)6-NH-l-Ala in dioxane. The latter case resembles the spectrum observed in the presence of human serum albumin. Binding to the helical polypeptide melittin and the antiparallel β-sheet peptide, gramicidin S, in aqueous solutions results in opposite signs of the bilirubin CD bands. The quenching of tryptophan fluorescence in melittin, in aqueous solution and enhancement of bilirubin fluorescence in dioxane on binding to gramicidin S have been used to monitor pigment-peptide interactions. The results suggest the utility of bilirubin as a conformational probe.

Stresses around two equal circular elastic inclusions in a pressurised cylindrical shell

The stress problem of two equal circular elastic inclusions in a pressurised cylindrical shell has been solved by using single inclusion solutions together with Graf’s addition theorem. The effect of the inter-inclusion distance on the interface stresses in the shell as well as in the inclusion is studied. The results obtained for small values of curvature parameter fi @*=(a*/8Rt) [12(1-v*)]“*, a, R, t being inclusion radius and shell radius and thickness) when compared with the flat-plate results show good agreement. The results obtained in non-dimensional form are presented graphically.

A circular dichroism study of (+) gossypol binding to proteins

The circular dichroism bands of (+) gossypol in the spectral region 300–400 nm have been shown to be sensitive to interactions with proteins. Using CD spectroscopy, gossypol has been shown to interact with lactate dehydrogenase, malate dehydrogenase, alkaline phosphatase, lysozyme, protamine and poly-L-lysine. Binding to proteins generally results in a pronounced red shift of the long wavelength CD band (not, vert, similar 380–430 nm) accompanied by a reduction in ellipticity. The changes in spectral parameters of the 1Lb binaphthyl transtion may reflect a distortion from a nearly perpendicular gossypol conformation, on binding to proteins.

Thermal stresses around circular holes in spherical shells

The thermal stress problem of a circular hole in a spherical shell of uniform thickness is solved by using a continuum approach. The influence of the hole is assumed to be confined to a small region around the opening. The thermal stress problem is converted as usual to an equivalent boundary value problem with forces specified around the cutout. The stresses and displacement are obtained for a linear variation of temperature across the thickness of the shell and presented in graphical form for ready use.

Stresses and Displacements under a Flexible Circular Foundation in the Presence of Friction or Adhesion

Die Vorliegende Arbeit beschäftigt sich mit den Spannungen und Verschiebungen an einem elastischen Halbraum unter einem kreisförmigen biegsamen Fundament, wenn an der Kontaktfläche vollkommenes Haften besteht. Das gemischte Randwertproblem wird mit Hilfe von Hankel-Transformationen auf duale Integralgleichungen von Titchmarsh- Typ zurückgeführt. Für die Berechnung der Spannungen und Verschiebungen werden Gaußsche Quadraturformeln benutzt. Die Ergebnisse werden mit denen verglichen, die man bei glattem Fundament erhält, und der Einfluß der Poisson-Zahl auf die Spannungen und Verschiebungen wird deutlich gemacht. Schließlich werden die Ergebnisse für den praktischen Gebrauch in Diagrammen und Tabellen zusammengefaßt.

Response of Circular Footings to Vertical Vibrations

In this paper, analog solutions are presented for the response of a circular footing resting on an elastic half-space with uniform and parabolic contact pressure distributions and subjected to frequency dependent and frequency independent excitations. In addition, an analog solution to a rigid circular footing subjected to frequency dependent excitation is also presented. The results have been compared with the rigorous solution of Sung and the agreement is found to be good.

Stresses and Displacements under a Flexible Circular Foundation in the Presence of Friction or Adhesion

Die Vorliegende Arbeit beschäftigt sich mit den Spannungen und Verschiebungen an einem elastischen Halbraum unter einem kreisförmigen biegsamen Fundament, wenn an der Kontaktfläche vollkommenes Haften besteht. Das gemischte Randwertproblem wird mit Hilfe von Hankel-Transformationen auf duale Integralgleichungen von Titchmarsh- Typ zurückgeführt. Für die Berechnung der Spannungen und Verschiebungen werden Gaußsche Quadraturformeln benutzt. Die Ergebnisse werden mit denen verglichen, die man bei glattem Fundament erhält, und der Einfluß der Poisson-Zahl auf die Spannungen und Verschiebungen wird deutlich gemacht. Schließlich werden die Ergebnisse für den praktischen Gebrauch in Diagrammen und Tabellen zusammengefaßt.

Mechanics of transition in an axisymmetric laminar boundary layer on a circular cylinder

Measurements of the growth of artificially generated turbulent spots and intermittency distribution in the transition region on a circular cylinder in axial flow show that the instability Reynolds number of 11,000 has a marked effect on the properties. In particular, it is found that the spot production in the initial region when a single turbulent spot has not yet wrapped around the cylinder and the propagation is essentially two-dimensional, is significantly altered. But the transition in the downstream or latter region, where most of the turbulent spots propagate onedimensionally (like the turbulent plugs in a pipe), is not affected. When the radius Reynolds number is more than 11,000, the intermittency law in the initial region is essentially the same as in twodimensional flow on a flat plate and in the latter region it is the one-dimensional flow in a pipe, the demarcation between the two regions being quite sharp.

Axisymmetric stress distribution in a transversely isotropic thick plate with a circular hole

An exact solution for the stresses in a transversely isotropic infinite thick plate having a circular hole and subjected to axisymmetric uniformly distributed load on the plane surfaces has been given. The solution is in the form of Fourier-Bessel series and integrals. Numerical results for the stresses are given using the elastic constants for magnesium, and are compared with the isotropic case.

Energy use in Indian household sector - An actor-oriented approach

Over the years, significant changes have taken place with regard to the type as well the quantity of energy used in Indian households. Many factors have contributed in bringing these changes. These include availability of energy, security of supplies, efficiency of use, cost of device, price of energy carriers, ease of use, and external factors like technological development, introduction of subsidies, and environmental considerations. The present paper presents the pattern of energy consumption in the household sector and analyses the causalities underlying the present usage patterns. It identifies specific (groups of) actors, study their specific situations, analyse the constraints and discusses opportunities for improvement. This can be referred to ``actor-oriented'' analysis in which we understand how various actors of the energy system are making the system work, and what incentives and constraints each of these actors is experiencing. It analyses actor linkages and their impact on the fuel choice mechanism. The study shows that the role of actors in household fuel choice is significant and depends on the level of factors - micro, meso and macro. It is recommended that the development interventions should include actor-oriented tools in energy planning, implementation, monitoring and evaluation. The analysis is based on the data from the national sample survey (NSS), India. This approach provides a spatial viewpoint which permits a clear assessment of the energy carrier choice by the households and the influence of various actors. The scope of the paper is motivated and limited by suggesting and formulating a powerful analytical technique to analyse the problem involving the role of actors in the Indian household sector.

Stress analysis of a thick plate having a circular hole under axisymmetric radial load

In this paper a solution for the determination of stresses and displacements in a thick plate having a cylindrical hole subjected to localised hydrostatic loading has been given. Detail numerical results have been presented and compared with the results of an infinite hole subjected to localised hydrostatic load and a semiinfinite hole subjected to localised end load. It has been shown that for certain ratio of thickness of the pate to the radius of the hole and loading, the results could be obtained by using the solution of infinite or semiinfinite hole subjected to the same hydrostatic loading.

Effect of membrane action on the plastic collapse load of circular orthotropic slabs with fixed edges

In the case of reinforced concrete slabs fixed at the boundaries, considerable enhancement in the load carrying capacity takes place due to compressive membrane action. In this paper a method is presented to analyse the effects of membrane action in fixed orthotropic circular slabs, carrying uniformly distributed loads. Depending on the radial moment capacity being greater or less than the circumferential moment capacity, two cases of orthotropy have been considered. Numerical results are worked out for certain assumed physical parameters and for different coefficients of orthotropy. Variations of load and bending moments with the central deflection are presented.