Nuclear Orientation Studies of Magnetism in Single Crystal Pr0.5Nd0.5Ni

The angular distributions of -rays from ¹⁴²Pr, ¹⁴⁷Nd and ¹⁴⁴Pm in Pr_0.5Nd_0.5Ni were investigated by means of low-temperature nuclear orientation. The results show that the Pr and Nd electronic moments order along the c- and a-axis, respectively. Pm ions introduced as a very dilute magnetic impurity, preferentially align with the Nd ions.     

A nonsmooth Newton method for variational inequalities,II: Numerical results

This paper presents the results of extensive computational testing of the modified damped Newton algorithm for solving variational inequality problems presented in Part I [8].Corresponding author.     

The analytical utility of thermally desorbed polydimethylsilicone membranes for in-vivo sampling of volatile organic compounds in and on human skin

A thermally-desorbed polydimethylsilicone (PDMS) membrane approach with analysis by gas chromatography-mass spectrometry has been developed and characterised, to enable the VOC arising in, and on skin, from glandular secretions, exogenous materials, products of perfusion from blood, and microbiological metabolites to be sampled in a single procedure. In-vitro studies using a series of volatile fatty acid standards indicated that the recovery efficiency of the technique increased with decreasing volatility; for example, the recovery of hexanoic acid was 3.3 times greater than that for 2-methylpropanoic acid. The relative standard deviation of the methodology decreased with decreasing volatility; RSD = 19% for 2-methylpropanoic acid and RSD = 7% for hexanoic acid. Sampled-mass vs. response relationships were modelled satisfactorily using linear regression analysis with regression coefficients in the range 0.95 to 0.998. In-vivo reproducibility was assessed though the analysis of the responses of 1-dodecane, 3,7-dimethyloct-1-ene, 2-propenoic acid, 2-ethylhexyl ester, 2-ethylhexan-1-ol, butanoic, 2-ethylhexylester, and junipen (1,4-methanoazulene, decahydro-4,8,8-trimethyl-9-methylene-); six compounds selected at random retention times from a GC-MS chromatographic VOC profile of human skin containing several hundred resolved and partially resolved compounds. Five samples were obtained simultaneously from the forearm of a healthy male participant. The in-vivo sample masses were estimated to be in the range 50 pg to 100 ng per sample with observed RSD falling between 15% and 32%; in line with a Horwitz trend. Increasing the sample time from 5 min to 120 min generally resulted in an enrichment of the VOC recovered, and for many VOC substantial increases in sensitivity (x7) were observed over this time range as the PDMS sampling-patch approached equilibrium with the underlying skin. Nevertheless, more volatile components, 2,4,6-trimethylcarbazole for instance, were observed to be lost from the analysis with increasing sample time, in a manner analogous with breakthrough behaviour in adsorbent traps. Finally, a 10 day storage study at 4 degrees C suggested that micro-biological factors were significant in their effect on sample stability. Significant changes (up to x8) were observed in the masses of compounds recovered post storage. These studies confirmed that polydimethylsilicone membrane sampling patches of human skin provide rich and analytical useful data. It is important to note that care in experimental design is needed to avoid sampling artefacts being introduced through sampling selectivity, and/or, sample instability where samples are stored for longer than 24 h at 4 degrees C or higher.     

Discrete Morse Theoretic Algorithms for Computing Homology of Complexes and Maps

We provide explicit and efficient reduction algorithms based on discrete Morse theory to simplify homology computation for a very general class of complexes. A set-valued map of top-dimensional cells between such complexes is a natural discrete approximation of an underlying (and possibly unknown) continuous function, especially when the evaluation of that function is subject to measurement errors. We introduce a new Morse theoretic preprocessing framework for deriving chain maps from such set-valued maps, and hence provide an effective scheme for computing the morphism induced on homology by the approximated continuous function.     

Finite-dimensional variational inequality and nonlinear complementarity problems: A survey of theory,algorithms and applications

Over the past decade, the field of finite-dimensional variational inequality and complementarity problems has seen a rapid development in its theory of existence, uniqueness and sensitivity of solution(s), in the theory of algorithms, and in the application of these techniques to transportation planning, regional science, socio-economic analysis, energy modeling, and game theory. This paper provides a state-of-the-art review of these developments as well as a summary of some open research topics in this growing field.The research of this author was supported by the National Science Foundation Presidential Young Investigator Award ECE-8552773 and by the AT&T Program in Telecommunications Technology at the University of Pennsylvania.The research of this author was supported by the National Science Foundation under grant ECS-8644098.