Regression Analysis of Fracture Toughness for Secondary Osteons Located in Human Cortical Bone

An experiment was carried out in order to locate and quantify osteon types within a sample of cortical bone taken from a human tibia. This was done using a microscope-camera assembly and the BioQuant computer software. The results of this were correlated with a previous experiment’s results on fracture toughness so that an analysis could be run on the data in order to determine the factors that most affect the value of fracture toughness of this cortical bone. Results were examined closely and the analysis repeated until the author was satisfied that the best possible model for fracture toughness had been achieved. A combination of usable parameters included: region, porosity, volume fraction of lightfield osteons, volume fraction of hooped osteons, volume fraction of dark osteons, volume fraction of alternating osteons, volume fraction total, density, average diameter total, average diameter of hooped osteons, average diameter of lightfield osteons, average diameter of darkfield osteons and average diameter of alternating osteons. This model explains the parameters that most affect fracture toughness by using a regression analysis, which also provides a regression equation to show exactly how much each specific parameter affects the fracture toughness valu

Contexts of social action: guest editors' introduction

Cataloged from PDF version of article.In traditional linguistic accounts of context, one thinks of the immediate features of a speech situation, that is, a situation in which an expression is uttered. Thus, features such as time, location, speaker, hearer and preceding discourse are all parts of context. But context is a wider and more transcendental notion than what these accounts imply. For one thing, context is a relational concept relating social actions and their surroundings, relating social actions, relating individual actors and their surroundings, and relating the set of individual actors and their social actions to their surroundings

A thin film model for corotational Jeffreys fluids under strong slip

We derive a thin film model for viscoelastic liquids under strong slip which obey the stress tensor dynamics of corotational Jeffreys fluids.Comment: 3 pages, submitted to Eur. Phys. J.

Slip-controlled thin film dynamics

In this study, we present a novel method to assess the slip length and the viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyse dewetting fronts of low molecular weight polystyrene melts on Octadecyl- (OTS) and Dodecyltrichlorosilane (DTS) polymer brushes. Using a thin film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity. We study polymer films with thicknesses between 50 nm and 230 nm and various temperatures above the glass transition. We find slip lengths from 100 nm up to 1 micron on OTS and between 300 nm and 10 microns on DTS covered silicon wafers. The slip length decreases with temperature. The obtained values for the viscosity are consistent with independent measurements.Comment: 4 figure

Scale-by-scale analysis of probability distributions for global MODIS-AQUA cloud properties: how the large scale signature of turbulence may impact statistical analyses of clouds

Means, standard deviations, homogeneity parameters used in models based on their ratio, and the probability distribution functions (PDFs) of cloud properties from the MODerate resolution Infrared Spectrometer (MODIS) are estimated globally as function of averaging scale varying from 5 to 500 km. The properties – cloud fraction, droplet effective radius, and liquid water path – all matter for cloud-climate uncertainty quantification and reduction efforts. Global means and standard deviations are confirmed to change with scale. For the range of scales considered, global means vary only within 3% for cloud fraction, 7% for liquid water path, and 0.2% for cloud particle effective radius. These scale dependences contribute to the uncertainties in their global budgets. Scale dependence for standard deviations and generalized flatness are compared to predictions for turbulent systems. Analytical expressions are identified that fit best to each observed PDF. While the best analytical PDF fit to each variable differs, <i>all</i> PDFs are well described by log-normal PDFs when the mean is normalized by the standard deviation inside each averaging domain. Importantly, log-normal distributions yield significantly better fits to the observations than gaussians at all scales. This suggests a possible approach for both sub-grid and unified stochastic modeling of these variables at all scales. The results also highlight the need to establish an adequate spatial resolution for two-stream radiative studies of cloud-climate interactions

Slip vs viscoelasticity in dewetting thin films

Ultrathin polymer films on non-wettable substrates display dynamic features which have been attributed to either viscoelastic or slip effects. Here we show that in the weak and strong slip regime effects of viscoelastic relaxation are either absent or not distinguishable from slip effects. Strong-slip modifies the fastest unstable mode in a rupturing thin film, which questions the standard approach to reconstruct the effective interface potential from dewetting experiments.Comment: 4 pages, submitted to Eur. Phys. J.

Editorial: ultrasound surveillance of hepatocellular carcinoma in the 21st century – authors’ reply

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136042/1/apt13910.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136042/2/apt13910_am.pd