The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Sven Hovmoller - One of the best experts on this subject based on the ideXlab platform.

  • three dimensional electron diffraction as a Complementary Technique to powder x ray diffraction for phase identification and structure solution of powders
    IUCrJ, 2015
    Co-Authors: Sven Hovmoller
    Abstract:

    Phase identification and structure determination are important and widely used Techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful Technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are Complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods will become crucially important in the near future.

Jose Leonardo Oliveira Mattos - One of the best experts on this subject based on the ideXlab platform.

Sergei G Kazarian - One of the best experts on this subject based on the ideXlab platform.

  • compaction of pharmaceutical tablets with different polymer matrices studied by ftir imaging and x ray microtomography
    Journal of Pharmaceutical Sciences, 2008
    Co-Authors: Patrick S Wray, K Andrew L Chan, James A Kimber, Sergei G Kazarian
    Abstract:

    Water soluble polymers are often used in tablet compaction for their desirable compaction and dissolution properties. ATR-FTIR spectroscopic imaging has been used to analyze in situ the spatial distribution of different components in tablets with different compositions. Caffeine tablets made of three different polymer matrices, microcrystalline cellulose, hydroxypropyl methylcellulose (HPMC) and lactose, were investigated. It was found that the distribution of caffeine is strongly affected by the composition of polymer matrix used in the tablet. X-ray tomography was used to analyze the caffeine distribution as a Complementary Technique. The results obtained were compared to the ATR-FTIR spectroscopic images.

M. Rees - One of the best experts on this subject based on the ideXlab platform.

  • COMPSAC - A testing methodology framework
    Proceedings. Fourteenth Annual International Computer Software and Applications Conference, 1
    Co-Authors: James Collofello, T. Fisher, M. Rees
    Abstract:

    The authors present a testing methodology framework which attempts to provide guidance in testing Technique selection and application. The framework defines several testing levels with Complementary Technique groups defined for each level. Each testing Technique group is a collection of testing Techniques with a common objective and emphasis. In addition, several categories of testing metrics are defined which can be utilized to increase testing effectiveness. The proposed testing methodology framework was initially developed to satisfy the diverse project needs of one organization. The methodology framework, however, is expandable and can be customized to meet the needs of other organizations and updated to reflect technology improvements in the testing area. >

John N Haselden - One of the best experts on this subject based on the ideXlab platform.