Interest In Examination Research Articles

High Precision Spatial Positioning

AbstractToday, computed tomography (CT) is an established method with synchrotron radiation sources to obtain volume information from numerous sample types at micrometer resolution. However, it is a fact that the examination of extended flat microsystems or planar test objects is often unsatisfactory when the sample is considerably larger than the area of interest for examination. The considerable variation in X‐ray transmission during a scan often creates artefacts during reconstruction. This limitation was overcome by introducing a new imaging method which now enables calculating threedimensional representations of flat, widely extended objects. However, to obtain meaningful raw data, the sample and the detector need to be positioned with high precision and stability. This demanding task was solved by employing a positioning system specifically developed for this task.

Spiral Structure of 7 Å Halloysite: Mathematical Models

AbstractHalloysite is used for targeted delivery of drugs and other biomolecules. Renewed interest in examination by X-ray diffraction (XRD) to predict the size of particles that can be loaded onto the nanotubes has resulted. Anhydrous halloysite consists of spiraled tubules the length and diameter of which can be determined by measurement using an electron microscope. In spite of ample evidence regarding the spiral structure of halloysite, current programs to evaluate the structure of halloysite nanotubes consider it to be a hollow tube or a cylinder which prevents accurate prediction of its structure and leads to misinformation about the sizes of materials that can be loaded onto the nanotubes. The overall objective of the current study was to derive equations to estimate the structure of halloysite nanotubes which take into consideration its spiral structure. The study of Fourier transform either by electron diffraction or XRD led to the measurement of the spiral thickness and the nature of the spiral. Calculations of the nanotube dimensions may determine the ability of these carriers to allow the mechanical delivery of certain drugs. Here the structure of hydrated halloysite (hollow cylindrical tubes with a doughnut-like cross-section) and anhydrous halloysite (spiraled or helical structure) are described as previously reported in the literature. The Fourier transform of the spiraled structure was selected based on three different kinds of spirals: the Archimedean spiral, the Power spiral, and the Logarithmic spiral. Programs used to define the crystal structure of materials and to calculate the Fourier transform need to take the spiral structure into consideration.

Application of polynomial projection ensembles to hedging crude oil commodity risk

Although the rapid expansion in derivative market in previous decades has drawn research in both theory and practice of hedging against commodity risk, recent volatile fluctuations in crude oil prices in world market have renewed profound interest in examination of existing and development of new hedging models and strategies. In this paper, we propose and develop a methodological framework for applying individual and ensembles of polynomial projection models to hedge against oil commodity price risk. The study also comparatively evaluates the hedging performances of these projection models and benchmarks them against naïve hedging, VEC–GARCH model, and the case of no hedging. In addition, the empirical analysis considers a trader’s level of risk aversion in commodity hedging as well as the adoption of transaction cost. Our findings indicate promising out-of-sample hedging capability by polynomial projection models. Also, different forms of integrated ensembles of projections outperform individual polynomial projections, suggesting the usefulness of ensemble structure in enhancement of hedging in an uncertain environment.

Neutron transmission and quasi‐elastic neutron scattering in polymer hydrogels

AbstractInvestigations of hydrogels with high water contents have recently acquired special significance. Hydrogels are crosslinked three‐dimensional networks of water‐soluble macromolecules saturated by water or water solutions of different substances. The interest in examination the fundamental physical properties for such systems is related to their numerious applications. Using neutron transmission and quasi‐elastic neutron scattering (QENS), the mass transfer and self‐diffusion processes of water and water solutions in gelatin and poly(acrylamide) hydrogels were studied. It was shown that the macroscopic liquid flow through network of quasi‐porous polymer gels at relatively low pressure gradients as well as self‐diffusion of water and water solutions in the above systems are adequately described by “effective medium” approach. QENS data were also interpreted using an approach that accounts for the hierarchy of time scales of molecular motions: slow collective motions of liquid molecules contained in Lagrange's clusters and rapid single‐particle motions. The friction and self‐diffusion coefficient data were used to estimate the effective pore sizes of gels at different polymer concentrations as well as the mean Lagrange's cluster sizes.

Fact and the Comprehensive Examination

SINCE the rise of interest in examinations in this country -the discussion question, the new-type objective forms, and more recently the comprehensive terminal examination-many have argued the importance of facts. According to one group of examiners, definite factual items-those items which are accepted as true-must be the solid basis of examining. These examiners usually advocate a wide sampling of definite short-answer items. Another group, influenced more or less by the experiences of the English universities of Oxford and Cambridge, have vaguely sought something less tangible than facts in their examining, an ability which they feel is more important. It is partly the selection and expression of relevant ideas, partly the original organization of ideas, and partly a keen appreciation of the historic-philosophical reference of any important problem. To the second group of examiners facts make up the skeleton, perhaps, but not the meat of scholarship. They do not motivate the thinker. They do not require consecutive reasoning on a broad problem. To be sure, such thinking cannot fail to use and yield but these are often by-products, supplementary to broad principles. What is a fact? Derived from the Latin factum, a fact stands for a deed or past event. It is true that there are facts which are ultimately final events bound up with definitions or identities (such as two and two equals four), but there are also facts, those items which are commonly accepted as fixed because they establish well-agreed-upon relationships within a system of postulates which is accepted. Medieval scholasticism had many identities and facts regarding the soul and God which could be derived provided one accepted the basic postulates and definitions. Some philosophers refer to orders of fact-ness, differentiating facts according to their verity or complexity or both. The idealists will allow absolute certainty for no as one's theory of knowledge or use of terms modifies the nature of the simplest perceptions; for example, some behaviorists do not grant the reality of consciousness. It may be that the most significant characteristic of a fact, or item