Analysis of strain bursts during nanoindentation creep of high‐density polyethylene

Nanoindentation creep experiments on polyethylene were carried out in order to investigate dislocation‐based plastic deformation mechanisms. Similarly to that reported in a recent paper (Li J and Ngan AHW, Scr Mater 62 :488–491 (2010)), discrete deformation processes occur during nanoindentation creep tests which again seem to arise from the break‐off of dislocation avalanches. That interpretation is supported from systematic studies of the effect of variations of the loading rate and of the applied load on the number and the height of bursts. © 2015 Society of Chemical Industry     

The Effect of Zr Incorporation Caused by Ball Abrasion in a Milled Fe-Y2O3 Model Alloy

Y-O nanoparticles which are homogeneously distributed in the matrix can improve the thermal properties of steels. Several studies of mechanically alloyed steels showed that especially Y-Ti-O particles can cause a further improvement of the mechanical properties at elevated temperatures. It is also assumed that an addition of Zr instead of Ti may have a similar or even stronger effect. This study presents a new way of producing nanostructured ferritic alloys as Zr is incorporated by attrition of yttrium-stabilized zirconia balls during milling. Additionally, the effect of Zr incorporation is demonstrated as well as the particle size distribution of the Y-Zr-O nanoparticles analyzed by transmission electron microscopy. This is compared to a specimen milled with common steel balls. Atom probe tomography and transmission electron microscopy show that the incorporated zirconia lowers the minimum particle size and causes a finer particle distribution. This particle refinement causes a higher hardness after hipping.     

Membrane‐Supported Multichannel Microfluidic Solvent Extraction System

Although microfluidic solvent extraction (µSX) is a recent field in separation, its application is still limited to single‐channel microfluidic devices. However, the industrial application of microheat exchangers has already proven that parallelization of microchannels is an important tool to increase the specific device efficiency. Hence, in this study, a multichannel system for µSX is introduced. As a model process, D,L‐5‐phenylhydantoin was extracted from ethyl acetate into aqueous buffer. By means of different experimental setups, the potential and limitations of membrane‐supported multichannel µSX were investigated. The reactor dimensions perpendicular to flow and transmembrane mass transport are the most challenging factors for the introduced device.     

Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin

Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH) and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health.     

MMPI differentiation of panic disorder patients from other psychiatric outpatients.

A variety of Minnesota Multiphasic Personality Inventory (MMPI) techniques were used to determine differences in psychopathology between 60 outpatient panic disorder patients (PDPs) and 60 demographically matched psychiatric controls (PCs). PDPs showed less psychopathology than PCs on the clinical scales. PDPs had more neurotic code-type profiles, and PCs had more characterological profiles. An empirically constructed panic disorder (Pan) scale correctly classified 72% of PDPs and PCs in the cross-validation sample and 83% of the combined samples, suggesting potential clinical utility and the need for further validation. There were significant differences between PDPs with or without agoraphobia on the clinical scales or Pan scale. The Pan scale successfully differentiated PDPs from a small sample of PCs diagnosed with nonpanic anxiety disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on “Co-Evolution in the Successful Learning of Backgammon Strategy”

The results obtained by Pollack and Blair substantially underperform my 1992 TD Learning results. This is shown by directly benchmarking the 1992 TD nets against Pubeval. A plausible hypothesis for this underperformance is that, unlike TD learning, the hillclimbing algorithm fails to capture nonlinear structure inherent in the problem, and despite the presence of hidden units, only obtains a linear approximation to the optimal policy for backgammon. Two lines of evidence supporting this hypothesis are discussed, the first coming from the structure of the Pubeval benchmark program, and the second coming from experiments replicating the Pollack and Blair results.