The three-dimensional X-ray crystal microscope: A new tool for materials characterization

The three-dimensional (3-D) X-ray crystal microscope is a new nondestructive tool for the 3-D characterization of the mesoscopic and nanoscopic materials structure. A prototype microscope is installed on beamline 34-ID at the advanced photon source and has begun initial operation. The prototype microscope has a routine spatial resolution of approximately 0.5 × 0.5 × 1 μm³ and can probe tens to hundreds of microns below a sample surface, depending on the composition of the sample. For each volume element measured, the microscope can determine between 10 and 16 parameters. The measured parameters are the local crystallographic phase (1 deg of freedom), the Eulerian angles of crystal orientation (3 deg of freedom), and the plastic and/or elastic strain-tensor elements (6 to 12 deg of freedom). The time required to collect each volume element varies between 1 and 14 seconds, depending on the precision of the parameters and the sample complexity. Much faster data acquisition and much better spatial resolution are certain in the near future. Some initial results are presented to illustrate how the 3-D X-ray crystal microscope can provide unprecedented information about the 3-D structure of materials. This article is based on a presentation made at the symposium “Characterization and Representation of Material Microstructures in 3-D” held October 8–10, 2002, in Columbus, OH, under the auspices of ASM International’s Phase Transformations committee.     

Moderators of the Relationships Between Coworkers' Organizational Citizenship Behavior and Fellow Employees' Attitudes.

The authors developed and tested the prediction that the relationship hetween coworkers' organizational citizenship behaviors (OCBs) and fellow employees' attitudes depends on the supervisors' abusiveness. Results of a longitudinal study using data collected from 173 supervised employees at 2 points in time (separated by 7 months) suggested that coworkers' OCB was positively related to fellow employees' job satisfaction and affective commitment when abusive supervision was low. However, when abusive supervision was high, coworkers' OCB was negatively related to job satisfaction and was unrelated to organizational commitment. The results of a 2nd study were consistent with the idea that the attributions employees make for their coworkers' OCB explains the moderating effect of abusive supervision on the relationship between coworkers' OCB and job satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nanosecond response 'gasket-type' magnetic loop current monitor for relativistic electron beam current measurements

A fast response magnetic loop current monitor has been developed to measure relativistic electron beam return currents. The monitor has a rise time of about a nanosecond and a high degree of symmetry with moderate sensitivity, variable from about 1 to 10 V/kA. This simple monitor, with a thickness of 0.254 mm or less, is thin enough to be placed between segments of return current path in the diode or drift tube regions, is insensitive to flashover, beam and plasma bombardment, and radiation effects, and measures net current, thus offering some advantages over conventional magnetic probes, since the main components are outside of the vacuum region. Design criteria, an equivalent circuit analysis, and typical calibration waveforms are presented. Experimental current measurements for a pinched electron beam diode configuration using both conventional magnetic probes and 'gasket-type'current monitors with the FX-75 relativistic electron beam accelerator are presented.     

The stability of supply chains

A continuous time version of the well-known beer game model is derived and its stability and robust stability properties are investigated. Novelty originates from the treatment of pure process delays rather than exponential lags and it is shown that this can lead to diametrically different dynamics to the exponential lag case. The stability properties of the system are shown to support and quantify the qualitative empirical results of the beer game. Additional insight into the influence of certain model parameters is attained by their interpretation as the degree of mismatch in a Smith predictor regulator. The transient inability to supply all that is demanded is mimicked and shown to constitute an influential source of demand amplification. The analytical nature of these calculations engenders the capacity to improve supply chain dynamics through the synthesis and calibration of strategic supply chain trade-off problems.     

Production-inventory system controller design and supply chain dynamics

The paper deals with the modelling and control of aggregated production-inventory systems as described by differential equations. Hitherto, research in the area has been characterized by the approximation of production delays by first-order lags rather than more realistic pure delays. We demonstrate the substantial qualitative differences between these two approaches and thus generate the motivation for the rest of the paper, which tackles pure delay systems. The application of some relatively new design methodologies for delay systems yields four design choices that are tested for their performance over a range of criteria including stability robustness. The investigation is then extended to the model of a supply chain comprising many such productioninventory systems. The mechanism by which disturbances can be transmitted along the supply chain causing disruption and incurring costs to other supply chain echelons is elucidated. A heuristic feedback policy designed adaptively to tune the individual system designs in response to such disturbances is presented.     

Effects of chloride,thiocyanate and sulphate salts on β‐lactoglobulin–pectin associative complexes

Protein–polysaccharide complexes are used to improve protein stability and encapsulate high‐value ingredients, yet the influence of different salts on their formation has not been investigated. Using light scattering and turbidimetry, effects of chloride, sulphate and thiocyanate salts on β‐lactoglobulin and pectin complexes (protein/pectin ratio = 2:1 and 4:1) were determined in relation to effects of pH and ionic strength. Effects of anions on complex formation were significant at 25 mmol kg^?1 added ionic strength. Cation effects were not significant. At 100 mmol kg^?1 ionic strength, pH of complex formation increased with sulphate salts (pH 5.1) relative to chloride and thiocyanate salts (pH 4.9), while pH of coacervation increased with sulphate salts (pH 4.7) and decreased with thiocyanate salts (pH 4.4) relative to chloride salts (pH 4.6). Pure β‐lactoglobulin stability was otherwise reduced with thiocyanate salts below pH 5, implying a significant effect of pectin interactions.     

Optimization of Mixing and Mass Transfer in In-line Multi-Jet Ozone Contactors Using Computational Fluid Dynamics

Typical ozone mixing and mass transfer calculations are lumped approaches based on ideal operating conditions and can misrepresent behavior in real-life installations. This article models the effect of local hydrodynamics and mixing on the overall mass transfer of ozone into water with the aid of multiphase computational fluid dynamics (CFD). CFD models were validated with measured data from a pipeline ozone contactor installation which was optimized for more rapid, uniform mixing and mass transfer. Results emphasize the sensitivity of mixing quality to nozzle placement, size, orientation and spacing relative to main pipeline diameter and flows.     

Brick and mortar treatment by cream emulsion for improved water repellence and thermal insulation

A novel polymer cream was applied to brick and mortar in an attempt to reduce water absorption and to improve thermal insulation for household heating energy saving. Tests were carried out on surface energy, water contact angle, thermal conductivity and sorptivity of brick and mortar with and without cream treatment. A model house was built and a heating and monitoring system was developed to quantitatively evaluate the heating energy consumption in different conditions before and after cream treatment. It was found out that cream treatment can successfully impart good water repellence and enhanced the thermal insulation of the brick and mortar. The results from contact angle and surface energy measurements showed that the materials became highly hydrophobic. Experimental results from the model house showed approximately 9% heating energy consumption reduction in dry conditions and approximately 50% in wet conditions. In addition, the internal humidity typically was reduced to almost 1/3 of that of the control. It has been demonstrated that the novel cream treatment on masonry buildings can help reduce damp problems and save household heating energy consumption which can make a significant contribution to addressing social, environmental, ecological and economic problems resulting from climate change and global warming.