The Solomon Islands Hydrographic Unit (SIHU)

This paper is aimed at creating an awareness of the development of the Solomon Islands Hydrographic Unit (SIHU) to the hydrographic community in general. It will briefly outline the geography and history of discovery of the Solomons leading to the formation of the SIHU which now produces four-colour charts to International Standards and carries out large scale surveys according to a five-year rolling plan

Fiber Orientation Tensors and Mean Field Homogenization: Application to Sheet Molding Compound

Effective mechanical properties of fiber-reinforced composites strongly depend on the microstructure, including the fibers\u27 orientation. Studying this dependency, we identify the variety of fiber orientation tensors up to fourth-order using irreducible tensors and material symmetry. The case of planar fiber orientation tensors, relevant for sheet molding compound, is presented completely. Consequences for the reconstruction of fiber distributions and mean field homogenization are presented

Real-Time MRI of Continent and Stress Incontinent Male Patients after Orthotopic Ileal Neobladder

Introduction: The aim of this study was to correlate anatomic differences with continence status in male patients after cystoprostatectomy and ileal neobladder using real-time magnetic resonance imaging. Patients and Methods: Anatomic differences of 14 male patients (7 daytime continent and 7 stress incontinent) with ileal neobladder were determined by measuring the orthogonal distance of the bladder neck to the pubococcygeal line (PCL) to correlate anatomic differences with continence status. Results: The median distance of the bladder neck to PCL was +5.4 mm in continent patients before voiding whereas in incontinent patients it was +2 mm (p = 0.012). During the Valsalva maneuver, the median distance in continent patients was +4 and in incontinent patients -3 mm (p = 0.003). At the end of micturition, the median distance was +2.3 mm in continent patients and -12 mm in incontinent patients (p = 0.002). Conclusions: The bladder neck in incontinent patients showed more pronounced mobility in relation to the PCL during micturition and the Valsalva maneuver as compared to continent patients. In addition, the ileal neobladder was positioned significantly lower in the pelvis of incontinent patients. These preliminary results suggest that a stable bladder neck may be an important factor to reach full continence in patients with ileal neobladder. Copyright (C) 2011 S. Karger AG, Base

Perfils nutricionals de la carn i dels productes fets a base de carn

L'article presentamolt breument les diverses categories de productes carnis amb vuit taules de dades indicatives de composició i dades de productes elaborats a base de carn.The article presents briefly the various categories of meat products with eight tables of data composition and data indicative of processing meat

On the dependence of orientation averaging mean field homogenization on planar fourth-order fiber orientation tensors

A comprehensive study on the influence of planar fourth-order fiber orientation tensors on effective linear elastic stiffnesses predicted by orientation averaging mean field homogenization is given. Fiber orientation states of sheet molding compound (SMC) are identified to be in most cases approximately planar. In the planar case, all possible fourth-order fiber orientation tensors are given by a minimal invariant set of structurally differing planar fourth-order fiber orientation tensors. This set defines a three-dimensional body and forms the basis for a comprehensive study on the influence of a fiber orientation distribution in terms of a fourth-order tensor on homogenized stiffnesses. The methodology of this study is the main contribution of this work and can be adopted to analyze the orientation dependence of any quantity which is a function of a planar fourth-order fiber orientation tensor. At specific points inside the set of planar fiber orientation tensors, effective stiffnesses are calculated with selected mean field homogenization schemes. These schemes are based on orientation averaging of transversely isotropic elasticity tensors following Advani and Tucker (1987), which is explicitly recast as linear invariant composition in the fiber orientation tensors of second and fourth order of Kanatani third kind. A maximum entropy reconstruction of a fiber orientation distribution function based on leading fiber orientation tensors, enables a new numerical formulation of the Advani and Tucker average for the special planar case. Polar plots of Young’s modulus and generalized bulk modulus obtained by selected homogenization schemes are arranged on two-dimensional slices within the body of admissible fiber orientation tensors, visualizing the influence of the orientation tensor on the stiffness tensor. The orientation-dependence of the generalized bulk modulus differs significantly between selected homogenizations. Restrictions on the effective anisotropic material response caused by orthotropy of closure approximations are discussed

Fiber orientation distributions based on planar fiber orientation tensors of fourth order

Fiber orientation tensors represent averaged measures of fiber orientations inside a microstructure. Although, orientation-dependent material models are commonly used to describe the mechanical properties of representative microstructure, the influence of changing or differing microstructure on the material response is rarely investigated systematically for directional measures which are more precise than second-order fiber orientation tensors. For the special case of planar orientation distributions, a set of admissible fiber orientation tensors of fourth-order is known. Fiber orientation distributions reconstructed from given orientation tensors are of interest both for numerical averaging schemes in material models and visualization of the directional information itself. Focusing on the special case of planar orientations, this paper draws the geometric picture of fiber orientation distribution functions reconstructed from fourth-order fiber orientation tensors. The developed methodology can be adopted to study the dependence of material models on planar fourth-order fiber orientation tensors. Within the set of admissible fiber orientation tensors, a subset of distinct tensors is identified. Advantages and disadvantages of the description of planar orientation states in two- or three-dimensional tensor frameworks are demonstrated. Reconstruction of fiber orientation distributions is performed by truncated Fourier series and additionally by deploying a maximum entropy method. The combination of the set of admissible and distinct fiber orientation tensors and reconstruction methods leads to the variety of reconstructed fiber orientation distributions. This variety is visualized by arrangements of polar plots within the parameter space of fiber orientation tensors. This visualization shows the influence of averaged orientation measures on reconstructed orientation distributions and can be used to study any simulation method or quantity which is defined as a function of planar fourth-order fiber orientation tensors

Variety of fiber orientation tensors

Fiber orientation tensors are established descriptors of fiber orientation states in (thermo-)mechanical material models for fiber-reinforced composites. In this paper, the variety of fourth-order orientation tensors is analyzed and specified by parameterizations and admissible parameter ranges. The combination of parameterizations and admissible parameter ranges allows for studies on the mechanical response of different fiber architectures. Linear invariant decomposition with focus on index symmetry leads to a novel compact hierarchical parameterization, which highlights the central role of the isotropic state. Deviation from the isotropic state is given by a triclinic harmonic tensor with simplified structure in the orientation coordinate system, which is spanned by the second-order orientation tensor. Material symmetries reduce the number of independent parameters. The requirement of positive-semi-definiteness defines admissible ranges of independent parameters. Admissible parameter ranges for transversely isotropic and planar cases are given in a compact closed form and the orthotropic variety is visualized and discussed in detail. Sets of discrete unit vectors, leading to selected orientation states, are given