An X-ray absorption spectroscopy study of Mo oxidation in Pb at elevated temperatures

The corrosion of fuel cladding and structural materials by lead and lead-bismuth eutectic in the liquid state at elevated temperatures is an issue that must be considered when designing advanced nuclear systems and high-power spallation neutron targets. In this work, lead corrosion studies of molybdenum were performed to investigate the interaction layer as a function of temperature by X-ray absorption spectroscopy. In situ X-ray absorption measurements on a Mo substrate with a 3-6 μm layer of Pb deposited by thermal evaporation were performed at temperatures up to 900 °C and at a 15° angle to the incident X-rays. The changes in the local atomic structure of the corrosion layer are visible in the difference extended X-ray absorption fine structure and the linear combination fitting of the X-ray absorption near-edge structure to as-deposited molybdenum sample and molybdenum oxide (MoO₂ and MoO₃) standards. The data are consistent with the appearance of MoO₃ in an intermediate temperature range (650-800 °C) and the more stable MoO₂ phase dominating at high and low temperatures.     

A Rigorous Architectural Approach to Adaptive Software Engineering

The engineering of distributed adaptive software is a complex task which requires a rigorous approach. Software architectural (structural) concepts and principles are highly beneficial in specifying, designing, analysing, constructing and evolving distributed software. A rigorous architectural approach dictates formalisms and techniques that are compositional, components that are context independent and systems that can be constructed and evolved incrementally. This paper overviews some of the underlying reasons for adopting an architectural approach, including a brief “rational history” of our research work, and indicates how an architectural model can potentially facilitate the provision of self-managed adaptive software system. Much of the research has been supported by the Engineering and Physical Sciences Research Council and is currently partly supported by EPSRC Platform grant AEDUS 2 and a DTC grant.     

Micro parallel liquid chromatography for high-throughput compound purity analysis and early ADMET profiling

The Nanostream (Pasadena, CA) Veloce system, together with 24-column Brio cartridges, offers a novel approach to micro parallel liquid chromatography (μPLC). This system allows users to achieve unprecedented throughput for standard assays while matching the performance of conventional LC instrumentation, thus enabling routine compound purity assessment and physiochemical property profiling early in the drug discovery and development process.The Veloce system—which includes instrumentation, software, and replaceable microfluidic cartridges—incorporates pressure-driven flow to achieve chromatograms comparable to conventional high performance liquid chromatography (HPLC) instrumentation for a broad class of analytical applications while offering a dramatic increase in sample analysis capacity. The system enables parallel chromatographic separations and simultaneous, real-time UV detection. Each Nanostream Brio cartridge, made of polymeric materials, incorporates 24 columns packed with standard (C-18) stationary phase material to achieve reverse phase separations. Mixing and distribution of the mobile phase to each of the 24 columns is precisely controlled in each cartridge. The system provides an ideal platform to accelerate assessment of compound purity and physicochemical properties (i.e., log P, CHI, etc.) for a large number of compounds. In addition, the 24-fold increase in sample analysis capacity allows standard curve generation and simultaneous analysis of multiple replicates of samples in a single run.     

Vibrio vulnificus and Vibrio parahaemolyticus in U.S. retail shell oysters: a national survey from June 1998 to July 1999.

From June 1998 to July 1999, 370 lots of oysters in the shell were sampled at 275 different establishments (71%, restaurants or oyster bars; 27%, retail seafood markets: and 2%, wholesale seafood markets) in coastal and inland markets throughout the United States. The oysters were harvested from the Gulf (49%). Pacific (14%), Mid-Atlantic (18%), and North Atlantic (11%) Coasts of the United States and from Canada (8%). Densities of Vibrio vulnificus and Vibrio parahaemolyticus were determined using a modification of the most probable number (MPN) techniques described in the Food and Drug Administration's Bacteriological Analytical Manual. DNA probes and enzyme immunoassay were used to identify suspect isolates and to determine the presence of the thermostable direct hemolysin gene associated with pathogenicity of V. parahaemolyticus. Densities of both V. vulnifcus and V. parahaemolyticus in market oysters from all harvest regions followed a seasonal distribution, with highest densities in the summer. Highest densities of both organisms were observed in oysters harvested from the Gulf Coast, where densities often exceeded 10,000 MPN/g. The majority (78%) of lots harvested in the North Atlantic, Pacific, and Canadian Coasts had V. vulnificus densities below the detectable level of 0.2 MPN/g; none exceeded 100 MPN/g. V. parahaemolyticus densities were greater than those of V. vulnificus in lots from these same areas, with some lots exceeding 1,000 MPN/g for V. parahaemolyticus. Some lots from the Mid-Atlantic states exceeded 10,000 MPN/g for both V. vulnificus and V. parahaemolyicus. Overall, there was a significant correlation between V. vulificus and V. parahaemolyticus densities (r = 0.72, n = 202, P < 0.0001), but neither density correlated with salinity. Storage time significantly affected the V. vulnificus (10% decrease per day) and V. parahaemolyticus (7% decrease per day) densities in market oysters. The thermostable direct hemolysin gene associated with V parahaemolyticus virulence was detected in 9 of 3,429 (0.3%) V. parahaemolyticus cultures and in 8 of 198 (4.0%) lots of oysters. These data can be used to estimate the exposure of raw oyster consumers to V. vulnificus and V. parahaemolyticus.     

In situ TEM nanoindentation and dislocation-grain boundary interactions: a tribute to David Brandon

As a tribute to the scientific work of Professor David Brandon, this paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-grain boundary interactions. In particular, we have focused on the deformation characteristics of Al–Mg films. To this end, in situ nanoindentation experiments have been conducted in TEM on ultrafine-grained Al and Al–Mg films with varying Mg contents. The observed propagation of dislocations is markedly different between Al and Al–Mg films, i.e. the presence of solute Mg results in solute drag, evidenced by a jerky-type dislocation motion with a mean jump distance that compares well to earlier theoretical and experimental results. It is proposed that this solute drag accounts for the difference between the load-controlled indentation responses of Al and Al–Mg alloys. In contrast to Al–Mg alloys, several yield excursions are observed during initial indentation of pure Al, which are commonly attributed to the collective motion of dislocations nucleated under the indenter. Displacement-controlled indentation does not result in a qualitative difference between Al and Al–Mg, which can be explained by the specific feedback characteristics providing a more sensitive detection of plastic instabilities and allowing the natural process of load relaxation to occur. The in situ indentation measurements confirm grain boundary motion as an important deformation mechanism in ultrafine-grained Al when it is subjected to a highly inhomogeneous stress field as produced by a Berkovich indenter. It is found that solute Mg effectively pins high-angle grain boundaries during such deformation. The mobility of low-angle boundaries is not affected by the presence of Mg.Special title: Advanced Materials and Characterization: Proceedings of the Brandon Symposium; Guest Editors: Wayne D. Kaplan and Srinivasa Ranganathan     

Intentions in teasing: When "just kidding" just isn't good enough.

Teasing is ambiguous. Although the literal content of a tease is, by definition, negative, seldom do teasers intend for their tease to be taken literally. Toward this aim, teasers often attempt to mitigate the negative surface content of the tease by communicating via gesture, facial expression, or tone of voice that they are "just kidding." The research presented here suggests that such attempts often fall on deaf ears. Despite teasers' attempts to mitigate the tease, targets are often unaware of--and unmoved by--the teaser's benign intentions. As a result, teasers and targets systematically differ in their perceptions of teasing: Although it is often seen as innocent and playful by the teaser, it tends to be construed as considerably more malicious by the target. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response to “On the Radicality of New York’s Reforming the Energy Vision” by Ross Astoria

Dr. Jeff D. Makholm responds to Professor Ross Astoria’s criticms of Dr. Makholm’s submission: “The REVolution yields to a more familiar path: New York’s Reforming the Energy Visition (REV), Electricity Journal 29 (2016), 48–55 as follows.     

Climate Change, “Grid Neutrality,” and Electricity Distributors

My late colleague and friend Alfred Kahn relayed how President Jimmy Carter hired him in 1977 to head the Civil Aeronautics Board to reform and ultimately deregulate the US airline industry. Accepting the job, he told a group of airline executives (to their fury), “I really don't know one plane from the other. To me they are all marginal costs with wings.” He used that term to signal his intention of reforming the industry in keeping with economic principles, uninfluenced by the romance of air travel.     

Electricity Deregulation Under Siege

It has not been a good few years for the advance of competition in electricity supply in a number of places in the world.