A survey of sea diseases on South African ships

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Bending with large deflection of a clamped rectangular plate with length-width ratio of 1.5 under normal pressure

The Von Karman equations for a thin flat plate with large deflections are solved for the special case of a plate with clamped edges having a ratio of length to width of 1.5 and loaded by uniform normal pressure. Center deflections, membrane stresses, and extreme-fiber bending stresses are given as a function of pressure for center deflections up to twice the thickness of the plate. For small deflections the results coincide with those obtained by Hencky from the linear theory. The maximum stresses and center deflection at high pressures differ less than 3 percent from those derived by Bostnov for an infinitely long plate with clamped edges. This agreement suggests that clamped plates with a length-to-width ratio greater than 1.5 may be reared as infinitely long plates for purposes of design

Square plate with clamped edges under normal pressure producing large deflections

A theoretical analysis is given for the stresses and deflections of a square plate with clamped edges under normal pressure producing large deflections. Values of the bending stress and membrane stress at the center of the plate and at the midpoint of the edge are given for center deflections up to 1.9 times the plate thickness. The shape of the deflected surface is given for low pressures and for the highest pressure considered. Convergence of solution is considered and it is estimated that the possible error is less than 2 percent. The results are compared with the only previous approximate analysis known to the author and agrees within 5 percent. They are also shown to compare favorably with the known exact solutions for the long rectangular plate and the circular plate

Effects of the electrostatic environment on superlattice Majorana nanowires

Finding ways of creating, measuring, and manipulating Majorana bound states (MBSs) in superconducting-semiconducting nanowires is a highly pursued goal in condensed matter physics. It was recently proposed that a periodic covering of the semiconducting nanowire with superconductor fingers would allow both gating and tuning the system into a topological phase while leaving room for a local detection of the MBS wave function. We perform a detailed, self-consistent numerical study of a three-dimensional (3D) model for a finite-length nanowire with a superconductor superlattice including the effect of the surrounding electrostatic environment, and taking into account the surface charge created at the semiconductor surface. We consider different experimental scenarios where the superlattice is on top or at the bottom of the nanowire with respect to a back gate. The analysis of the 3D electrostatic profile, the charge density, the low-energy spectrum, and the formation of MBSs reveals a rich phenomenology that depends on the nanowire parameters as well as on the superlattice dimensions and the external back-gate potential. The 3D environment turns out to be essential to correctly capture and understand the phase diagram of the system and the parameter regions where topological superconductivity is establishedWe thank E. J. H. Lee, H. Beidenkopf, E. G. Michel, N. Avraham, H. Shtrikman, and J. Nygård for valuable discussions. Research supported by the Spanish MINECO through Grants No. FIS2016-80434-P, No. BES-2017-080374, and No. FIS2017-84860-R (AEI/FEDER, EU), the European Union's Horizon 2020 research and innovation programme under the FETOPEN Grant Agreement No. 828948 and Grant Agreement LEGOTOP No. 788715, the Ramón y Cajal programme RYC-2011-09345, the María de Maeztu Programme for Units of Excellence in R&D (MDM-2014-0377), the DFG (CRC/Transregio 183, EI 519/7- 1), the Israel Science Foundation (ISF), and the Binational Science Foundation (BSF

Square plate with clamped edges under normal pressure producing large deflections

A theoretical analysis is given for the stresses and deflections of a square plate with clamped edges under normal pressure producing large deflections. Values of the bending stress and membrane stress at the center of the plate and at the midpoint of the edge are given for center deflections up to 1.9 times the plate thickness. The shape of the deflected surface is given for low pressures and for the highest pressure considered. Convergence of the solution is considered and it is estimated that the possible error is less than 2 percent. The results are compared with the only previous approximate analysis known to the author and agree within 5 percent. They are also shown to compare favorably with the known exact solutions for the long rectangular plate and the circular plate

Bending of Rectangular Plates with Large Deflections

The solution of von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, McPherson, and Levy. The deflections for a square plate under lateral pressure are compared with experimental and theoretical results by Kaiser. It is found that the effective widths agree closely with Marguerre's formula and with the experimentally observed values and that the deflections agree with the experimental results and with Kaiser's work

Large-deflection theory of curved sheet

Equations are given for the elastic behavior of initially curved sheets in which the deflections are not small in comparison with the thickness, but at the same time small enough to justify the use of simplified formulas for curvature. These equations are solved for the case of a sheet with circular cylindrical shape simply supported along two edges parallel to the axis of the generating cylinder. Numerical results are given for three values of the curvature and for three ratios of buckle length to buckle width. The computations are carried to buckle deflections of about twice the sheet thickness. It was concluded that initial curvature may cause an appreciable increase in the buckling load but that, for edge strains which are several times the buckling strain, the initial curvature causes a negligibly small change in the effective width

The triad of thrombocytopenia, eczema and infection (Wiskott-Aldrich's Syndrome)

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Stem cells and the origin of gliomas: A historical reappraisal with molecular advancements.

The biology of both normal and tumor development clearly possesses overlapping and parallel features. Oncogenes and tumor suppressors are relevant not only in tumor biology, but also in physiological developmental regulators of growth and differentiation. Conversely, genes identified as regulators of developmental biology are relevant to tumor biology. This is particularly relevant in the context of brain tumors, where recent evidence is mounting that the origin of brain tumors, specifically gliomas, may represent dysfunctional developmental neurobiology. Neural stem cells are increasingly being investigated as the cell type that originally undergoes malignant transformation - the cell of origin - and the evidence for this is discussed