Specimen size and geometry effects on fracture toughness of Al2O3 measured with short rod and short bar chevron-notch specimens

Plane strain fracture toughness measurements were made on Al2O3 using short rod and short bar chevron notch specimens previously calibrated by the authors for their dimensionless stress intensity factor coefficients. The measured toughness varied systematically with variations in specimen size, proportions, and chevron notch angle apparently due to their influence on the amount of crack extension to maximum load (the measurement point). The toughness variations are explained in terms of a suspected rising R curve for the material tested, along with a discussion of an unavoidable imprecision in the calculation of K sub Ic for materials with rising R curves when tested with chevron notch specimens

Survival Strategies in Solidly Partisan States An Analysis of Centrist Appeals in 2012 U.S. Senate Debates

With the growing number of centrist senators diminishing on Capitol Hill, the next few election cycles will be crucial to the survival of this moderate group of lawmakers. Campaign debate scholars should investigate how vulnerable incumbents construct a centrist issue agenda and image to connect with voters in states ideologically incongruent with the incumbents’ parties. In doing so, debate scholars will also fill the lack of lower-level debate research. Utilizing both quantitative and qualitative methods, this analysis examined the debate appeals of Sens. Claire McCaskill (D-MO) and Scott Brown (R-MA). Findings suggest McCaskill’s issue agenda was congruent with a centrist image in contrast to Brown’s contradictory issue and image messaging. Additionally, centrist incumbents were more likely to acclaim a centrist image than attack their opponents’ partisanship

Fracture toughness of brittle materials determined with chevron notch specimens

The use of chevron-notch specimens for determining the plane strain fracture toughness (K sub Ic) of brittle materials is discussed. Three chevron-notch specimens were investigated: short bar, short rod, and four-point-bend. The dimensionless stress intensity coefficient used in computing K sub Ic is derived for the short bar specimen from the superposition of ligament-dependent and ligament-independent solutions for the straight through crack, and also from experimental compliance calibrations. Coefficients for the four-point-bend specimen were developed by the same superposition procedure, and with additional refinement using the slice model of Bluhm. Short rod specimen stress intensity coefficients were determined only by experimental compliance calibration. Performance of the three chevron-notch specimens and their stress intensity factor relations were evaluated by tests on hot-pressed silicon nitride and sintered aluminum oxide. Results obtained with the short bar and the four-point-bend specimens on silicon nitride are in good agreement and relatively free of specimen geometry and size effects within the range investigated. Results on aluminum oxide were affected by specimen size and chevron-notch geometry, believed due to a rising crack growth resistance curve for the material. Only the results for the short bar specimen are presented in detail

VisME: Visual microsaccades explorer

This work presents a visual analytics approach to explore microsaccade distributions in high-frequency eye tracking data. Research studies often apply filter algorithms and parameter values for microsaccade detection. Even when the same algorithms are employed, different parameter values might be adopted across different studies. In this paper, we present a visual analytics system (VisME) to promote reproducibility in the data analysis of microsaccades. It allows users to interactively vary the parametric values for microsaccade filters and evaluate the resulting influence on microsaccade behavior across individuals and on a group level. In particular, we exploit brushing-and-linking techniques that allow the microsaccadic properties of space, time, and movement direction to be extracted, visualized, and compared across multiple views. We demonstrate in a case study the use of our visual analytics system on data sets collected from natural scene viewing and show in a qualitative usability study the usefulness of this approach for eye tracking researchers. We believe that interactive tools such as VisME will promote greater transparency in eye movement research by providing researchers with the ability to easily understand complex eye tracking data sets; such tools can also serve as teaching systems. VisME is provided as open source software

Contribution of Different Scintigraphic Techniques to the Management of Medullary Thyroid Carcinoma

We compared three differenl scintigraphic techniques for the localization of neck recurrences and metastases in seven patients wiih medullary thyroid carcinoma one month to eight years after the first surgical intervention. Three successive scintigraphic studies were performed in five patients (6x3 studies) within two weeks using 201Tl chloride, 111In-labeled F(ab\u27)2 fragments of the anticarcinoembryonic antigen (anti-CEA) monoclonal antibody (MoAb) BW 431/31. and 131I meta-iodobenzylguanidine (MIBG). Additionally, 11 studies were performed wilh the 111In-labeled MoAb fragment BW 431/31 (seven studies) or the 99mTc-labeled intact anti-CEA MoAb BW 431/26 (four studies). The gold standards for classifying scintigraphic results were biopsy, histology, surgery, and cytology. Six regions were classified as positive or negalive in each study: thyroid region, four quadrants (lymph node regions) around the thyroid, and the region of the upper mediastinum. Of 36 sites, 201Tl was true positive (TP) in seven sites, false-positive (FP) in one site, true negative (TN) in 22 sites, and false-negative (FN) in six sites, resulting in a sensitivity of 54% and a specificity of 96%. 131I MIBG was TP in four sites, FP in none of the sites, TN in 23 sites, and FN in nine sites, with a sensitivity of 31% and a specificity of 100%. Immunoscintigraphy (102 sites overall) was TP in 16 sites, FP in five sites, TN in 77 siles, and FN in four siles. resulting in a sensitivity of 80% and a specificity of 94%. Immunoscintigraphy with 111In/99mTc anti-CEA F(ab\u27)2 fragment/intact antibody is superior to scintigraphy with 201Tl and 131I MIBG