Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles (open access)

Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop …
Date: August 5, 2009
Creator: Lawler, Katherine
System: The UNT Digital Library
Readiness scores as indicators of online faculty satisfaction. (open access)

Readiness scores as indicators of online faculty satisfaction.

The purpose of this study was to determine the relationships between online readiness scores and online faculty job satisfaction. Online readiness was assessed using the Readiness for Education At a Distance Indicator (READI) assessment. The READI assessment tool incorporated the independent variables of learning preference, technical competency, technical knowledge, personal attributes, on-screen reading speed and comprehension, and typing speed and accuracy. Online faculty job satisfaction was assessed using the National Study of Postsecondary Faculty (NSOPF) job satisfaction questions. Analysis of variance was used to determine whether there was a difference in satisfaction based on individual instructor learning preferences. Correlation coefficients were used to analyze the relationships between the remaining independent variables and online instructor satisfaction. The sample population (N=110) consisted of online faculty members at Tarrant County College. Most of the statistical analyses revealed non-significant results at the .05 alpha level. However, a significant difference in satisfaction with equipment and facilities was found based on instructor learning preference. Additionally, a statistically significant negative correlation was found between online instructor technical competency and satisfaction with benefits.
Date: May 2009
Creator: McLawhon, Ryan
System: The UNT Digital Library
From ZZ to ZH : How Low Can These Cross Sections Go or Everybody, Let's Cross Section Limbo! (open access)

From ZZ to ZH : How Low Can These Cross Sections Go or Everybody, Let's Cross Section Limbo!

We report on two searches performed at the D0 detector at the Fermi National Laboratory. The first is a search for Z di-boson production with a theoretical cross section of 1.4 pb. The search was performed on 2.6 fb{sup -1} of data and contributed to the first observation of ZZ production at a hadron collider. The second is a search for a low mass Standard Model Higgs in 4.2 fb{sup -1} of data. The Higgs boson is produced in association with a Z boson where the Higgs decays hadronically and the Z decays to two leptons. The ZZ search was performed in both the di-electron and di-muon channels. For the ZH search, we will focus on the muonic decays where we expanded the traditional coverage by considering events in which one of the two muons fails the selection requirement, and is instead reconstructed as an isolated track. We consider Higgs masses between 100 and 150 GeV, with theoretical cross sections ranging from 0.17 to 0.042 pb, and set upper limits on the ZH production cross-section at 95% confidence level.
Date: August 1, 2009
Creator: Strauss, Emanuel Alexandre
System: The UNT Digital Library