Sedflux 2.0: An advanced process-response model that generates three-dimensional stratigraphy

Sedflux 2.0 is the newest version of the Sedflux basin-filling model. Sedflux 2.0 provides a framework within which individual process-response models of disparate time and space resolutions communicate with one another to deliver multigrain-sized sediment load across a continental margin. Version 2.0 introduces a series of new process models, and the ability to operate in one of two modes to track the evolution of stratigraphy in either two or three dimensions. Additions to the 2D mode include the addition of models that simulate (1) erosion and deposition of sediment along a riverbed, (2) cross-shore transport due to ocean waves, and (3) turbidity currents and hyperpycnal flows. New processes in the 3D mode include (1) river channel avulsion, (2) two-dimensional diffusion due to ocean storms, and (3) two-dimensional flexure due to sediment loading. The spatial resolution of the architecture is typically 1–25 cm in the vertical and 10–100 m in the horizontal when operating in 2D mode. In 3D mode, the horizontal resolution usually extends to kilometers. In addition to fixed time steps (from days to hundreds of years), Sedflux 2.0 offers event-based time stepping as a way to conduct long-term simulations while still modeling low-frequency but high-energy events.     

Large displacement analysis of elastically constrained rotating disks with rigid body degrees of freedom

A central aspect of the linear vibration theory of rotating disks involves the concept of critical speeds. At such rotation speeds an axisymmetric disk can support a standing wave as recorded by a stationary observer. In such situations an applied space fixed constant force can give rise to a resonance in the disk. Such a response is of concern in industrial applications as diverse as circular saw blades and computer floppy disks. In such situations the magnitude of response may exceed the limits of linear theory. The present paper is concerned with the effects of large displacements upon the disk response in the neighborhood of such critical speeds. The effects of geometric nonlinearities and the influence of rigid body tilting and translation (caused by the boundary conditions) are considered. The equations of motion are based on Von Karman plate theory. The eigenfunctions of two self-adjoint eigenvalue problems, corresponding to the stress function and the transverse displacement, are determined and used as approximation functions in a numerically efficient Galerkin formulation. The coupled nonlinear ordinary differential equations of motion are solved using the Runge–Kutta method. Numerical results are presented for disks that are free to translate and rotate at their inner boundary and are constrained from lateral motion by space fixed linear springs. The effects of vibration magnitude on system response in the sub and super-critical speed regions are computed and the effects of large displacements on critical speed behavior and forced response are investigated. Experiments are conducted to verify the accuracy of the numerical results obtained in this paper.     

The applications of a commercial gas/liquid separator coupled with an inductively coupled plasma mass spectrometer

A commercially available hydride generator, with a novel membrane gas-liquid separator, has been coupled to a new ICPMS instrument which itself features many unique design considerations. Little or no optimization of the mass spectrometer or ionization source was required to obtain excellent analytical data; and a variety of matrices have been analysed.The elements As and Se are usually used to demonstrate the effectiveness of a hydride generation system, and these are of particular importance, bearing in mind potential Ar molecular overlaps with isotopes of interest. The flexibility of the hydride generation ICP-MS system is highlighted, with the inclusion of analytical figures of merit for the elements Sn, Sb, Ge and Hg, as well as As and Se. Data obtained by ‘standard’ pneumatic nebulization on the ICP-MS is compared with that obtained with the hydride generator for all of the elements.Improvements of between 50 and 100 times were gained in measurements of three sigma detection limits for all elements in the determinations, including Hg. Measurements were made on several isotopes for particular elements, and the data is included for the purposes of comparison. Stabilities of between 1 and 2.5% were obtained for 0.5 ppb solutions over 10 min measurement periods, all data is presented without using an internal standard.Finally, analytical data from seawater standards, spiked with low levels of As and Se and calibrated against aqueous standards, demonstrate excellent recoveries. This is of particular interest bearing in mind the well-documented molecular interferences from high chloride matrices on As and Se analysis.     

An analytical study on the effect of rigid body translational degree of freedom on the vibration characteristics of elastically constrained rotating disks

This study concerns the linear vibration behavior of annular spinning disk whose inner boundary is free to move in the axial direction while the body of the disk is constrained by a space fixed linear spring. It is shown, using analytical techniques based upon a three mode approximation, that constraining a spinning disk, free to have rigid body translation, with one space fixed spring does not change the critical speeds. Using an analysis, based on a two-mode approximation, the stability characteristics of a guided spinning disk due to the interaction between a rigid body translational mode and a forward or backward or reflected traveling wave are studied. It is shown that the interaction between the rigid body translational mode and a forward or backward traveling wave does not induce instability. In contrast to this situation it is shown that when the rigid body translational degree of freedom interacts with a reflected wave, depending on the speed and the stiffness of the spring, it may induce instability.     

Functional differences between keratins of stratified and simple epithelia

We present a simple method for extracting interference effects between chemical shift anisotropy (CSA) and dipolar coupling from spin relaxation measurements in macromolecules, and we apply this method to extracting cross-correlation rates involving interference of amide 15N CSA and 15N-1H dipolar coupling and interference of carbonyl 13C' CSA and 15N-13C' dipolar coupling, in a small protein. A theoretical basis for the interpretation of these rates is presented. While it proves difficult to quantitatively separate the structural and dynamic contributions to these cross-correlation rates in the presence of anisotropic overall tumbling and a nonaxially symmetric chemical shift tensor, some useful qualitative correlations of data with protein structure can be seen when simplifying assumptions are made.     

Bond strengths of the adhesive resin-amalgam interface

Generalized (diffuse) plane xanthoma (GPX) is a normolipaemic xanthomatosis that is very frequently associated with a haematological disorder, and especially with monoclonal gammapathies, which it may precede by several months or years. Here, we report a case of GPX associated with idiopathic Bence-Jones proteinuria, a very rare type of monoclonal gammopathy of undetermined significance. To our knowledge, this association has not been previously described.     

Assessment of medical technology: the role of engineers

Assessment of medical technologies is a multidisciplinary activity requiring the participation of engineers, clinicians and social scientists. The contribution of engineers has often been confined to the early stages of technical assessment. However, engineers have important inputs to make throughout the assessment process in their roles of developers, users and managers of technology. Engineers have found collaboration with clinical researchers possible through hospital-based work, but must also develop links with economists and other social scientists if they are to make a full contribution to comprehensive technology assessment.     

Acoustic emission for on-line reactor monitoring: Results of intermediate vessel test monitoring and reactor hot functional testing

This article discusses a program designed to develop the use of acoustic emission (AE) methods for continuous surveillance to detect and evaluate flaw growth in reactor pressure boundaries. Technology developed in the laboratory for identifying AE from crack growth and for using that AE information to estimate flaw severity is now being evaluated on an intermediate vessel test and on a reactor facility.A vessel, designated ZB-1, has been tested under fatigue loading with simulated reactor conditions at Mannheim, West Germany, in collaboration with the German Materialprüfungsanstalt (MPA), Stuttgart. Fatigue cracking from machined flaws and in a fabrication weld were both detected clearly by AE.AE data were measured on a US nuclear reactor (Watts Bar, Unit 1) during hot functional preservice testing. This demonstrated that coolant flow noise is a manageable problem and that AE can be detected under operational coolant flow and temperature conditions.     

Similarity in gallstone formation from 900 kcal/day diets containing 16 g vs 30 g of daily fat: evidence that fat restriction is not the main culprit of cholelithiasis during rapid weight reduction

Diets containing essentially no fat, 1-2 g fat per day, have resulted in cholesterol gallstones. Greater fat may result in less gallbladder stasis. Do gallstones form with greater fat content? We studied 272 moderately obese subjects who had normal gallbladder ultrasonograms. The 900 kcal/day liquid diets contained either 16 g fat (N = 94) or 30 g fat (N = 178) each day for 13 weeks. A second gallbladder ultrasound was performed. Sixteen of 94 (17.0%) of the 16-g fat group developed stones with a weight loss of 18 (+/- 7) kg and a body mass index (BMI) decrease of 6 (+/- 2) kg/m2. Twenty of 178 (11.2%) of the 30-g fat group developed stones (P = 0.18, no difference in stone formation) with similar weight loss of 20 (+/- 7) kg (P = 0.08) and BMI decrease of 7 (+/- 2) kg/m2 (P = 0.04). Substantial fat for rapid weight-reducing diets resulted in gallstone formation. Since experiments have shown that our higher fat diet, containing 10 g fat per meal, results in maximal gallbladder emptying, cholelithiasis from rapid weight loss may not be solely attributable to gallbladder stasis.