Imaging sediment structure: the emerging use of Magnetic Resonance Imaging (MRI) for 3D analysis of sediment structures and internal flow processes

Magnetic Resonance Imaging (MRI) can be used for 3D analysis of small-scale porous media structure and internal flow-related processes. It offers notable advantages over traditional sediment sampling (e.g. cores or surface-based scanning) as it is capable of high spatio-temporal resolution of the full 3D volume, including the sub-surface. Similarly, compared to X-Ray tomography, the extensive catalogue of MR pulse sequences typically provides: faster capture for imaging dynamic fluid processes; greater flexibility in resolving chemical species or tracers; and a safer radiation-free methodology. To demonstrate the relevance of this technique in geomorphological research, three exemplar applications are described: porous media structure of gravel bed rivers; measurements of fluid processes within aquifer pores and fractures; and, concentration mapping of contaminants through sand/gravel frameworks. Whilst, this emerging technique offers significant potential for visualizing many other ‘black-box’ processes important to the wider discipline, attention is afforded to discussion of the present constraints of the technique in field-based analysis

High-resolution dynamical modelling of the Antarctic stratospheric vortex

Progress is reported on the high-resolution three-dimensional numerical simulation of flows characteristic of the Antarctic wintertime stratosphere. The numerical model is a modified version of the Reading University sigma-coordinate used previously for tropospheric studies. Physical parameterizations are kept to a minimum in order to concentrate as much computing power as possible on simulating details of the dynamical processes. The major question addressed is whether the features observed in recent high-resolution two-dimensional simulations - namely: (1) the formation of a sharp edge to the vortex (seen in the potential vorticity field), (2) the survival of the polar vortex in a material entity, and (3) the formation of small-scale eddies rough the break-up of tongues of high potential vorticity drawn out from the polar vortex - are realized in three-dimensional simulations

Sonic impedance technique detects flaws in polyurethane foam spray-on insulation

Sonic impedance testing detects voids and unbonded regions as small as 1 inch in diameter by 0.03 inch thick. Measurements are made manually or by automatic scanning and the readout is made by meter or recorder

The effect of forcing on the spatial structure and spectra of chaotically advected passive scalars

The stationary distribution of passive tracers chaotically advected by a two-dimensional large-scale flow is investigated. The tracer field is force by resetting the value of the tracer in certain localised regions. This problem is mathematically equivalent to advection in open flows and results in a fractal tracer structure. The spectral exponent of the tracer field is different from that for a passive tracer with the usual additive forcing (the so called Batchelor spectrum) and is related to the fractal dimension of the set of points that have never visited the forcing regions. We illustrate this behaviour by considering a time-periodic flow whose effect is equivalent to a simple two-dimensional area-preserving map. We also show that similar structure in the tracer field is found when the flow is aperiodic in time.Comment: 7 pages, 9 figure

A study of the probability of depositing viable organisms on Mars during the Mariner 1964 mission

Probability of depositing viable organisms on Mars during 1964 Mariner missio

Ultrasonic scanning system for in-place inspection of brazed-tube joints

System detects defects of .051 cm in diameter and larger. System incorporates scanning head assembly including boot enclosed transducer, slip ring assembly, drive mechanism, and servotransmitter. Ultrasonic flaw detector, prototype recorder, and special recorder complete system

Ultrasonic scanning system for in-place inspection of brazed tube joints

A miniaturized ultrasonic scanning system for nondestructive in-place, non-immersion testing of brazed joints in stainless-steel tubing is described. The system is capable of scanning brazed tube joints, with limited clearance access, in 1/4 through 5/8 inch union, tee, elbow and cross configurations. The system has the capability to detect defective conditions now associated with material density changes in addition to those which are depended upon density variations. The system includes a miniaturized scanning head assembly that fits around a tube joint and rotates the transducer around and down the joint in a continuous spiral motion. The C-scan recorder is similar in principle to conventional models except that it was specially designed to track the continuous spiral scan of the tube joint. The scanner and recorder can be operated with most commercially available ultrasonic flaw detectors

Detecting Fraud in Bankrupt Municipalities Using Benford\u27s Law

This thesis explores if fraud or mismanagement in municipal governments can be diagnosed or detected in advance of their bankruptcies by financial statement analysis using Benford’s Law. Benford’s Law essentially states that the distribution of first digits from real world observations would not be uniform, but instead follow a trend where numbers with lower first digits (1, 2…) occur more frequently than those with higher first digits (…8,9). If a data set does not follow Benford’s distribution, it is likely that the data has been manipulated. This widespread phenomenon has been used as a tool to detect anomalies in data sets. The annual financial statements of Jefferson County, Vallejo City, and Orange County were analyzed. All the data sets showed overall nonconformity to Benford’s Law and therefore indicated that there was the possibility of fraud occurring. I find that Benford’s Law, had it been applied in real time to those financial statements, would have been able to detect that something was amiss. That would have been very useful because each of those jurisdictions subsequently went bankrupt. This paper demonstrates that Benford’s Law may in some cases be useful as an early indicator to detect the possibility of fraud in municipal governments’ financial data

Wolf\u27s Neck : the Gem of Casco Bay : the Charming Suburb of Freeport, Maine, with its Many Important Industries and Superior Granite Productions

https://digitalmaine.com/books/1015/thumbnail.jp