Low Hubble Constant from Type Ia Supernovae by van den Bergh's Method

An interesting way to calibrate the absolute magnitudes of remote Type Ia supernovae (SNe Ia) that are well out in the Hubble flow, and thus determine the value of the Hubble constant, H_0, has been introduced by van den Bergh. His approach relies on calculations of the peak absolute magnitudes and broad--band colors for SN Ia explosion models. It does not require any corrections for extinction by interstellar dust, and no SNe Ia are excluded on grounds of peculiarity. Within the last few years distances have been determined to the parent galaxies of six SNe Ia by means of Cepheid variables. Cepheid--based distances also have become available for three other SNe Ia if one is willing to use the distance to a galaxy in the same group in lieu of the distance to the parent galaxy itself. Here we determine the value of H_0 in a way that is analogous to that of van den Bergh, but now using Cepheid--based distances instead of calculated light curves. We obtain H_0 = 55 km/s/Mpc. This value, with Lambda=0 and Omega=1, corresponds to a cosmic expansion time of 12 Gyr, which is consistent with several recent determinations of the ages of globular clusters.Comment: Latex, 4 pages, 1 table, 1 figure, Submitted to Nature March 28, 1996. PostScript version available at http://www.nhn.ou.edu/~nugent

Mashed

My thesis film, Mashed , was created with multiple purposes in mind. I wanted to use and build on everything I learned at RIT, entertain both young and old audiences, and support my belief that shooting mediums should be a choice tailored to fit the needs and purposes of a character in a film. Popular trends in animation and visual effects sometimes overshadow the fact that technological advancements benefit more than just computer-generated graphics. Convincing stop-motion characters (and characters of other mediums) can benefit from these same advancements, and even coexist with multiple other styles within the same frame. My film is framed in a situation familiar to nearly everyone. It uses three major characters to tell its story, each of which is photographed separately using different filmmaking techniques. I have a real boy shot on HD video, a mashed potato monster brought to life with stop-motion animation, and a television super-hero created using computer-generated images. This production required three very distinct pipelines, each of which presented its own batch of challenges and adventures. The results were blended together into a film that I hope will not stand out as an attempt to mix media, but rather as a well-told story that was made using wise choices to create the strongest, most believable characters possible out of what was written on the page

Sou\u27wester: Volume 2, Number 4-December 25, 1938

https://digitalmaine.com/souwester/1002/thumbnail.jp

Sou\u27wester: Volume 2, Number 3-November 24, 1938

https://digitalmaine.com/souwester/1001/thumbnail.jp

Uncertainty in composite manufacturing and consequences for thermoplastic-thermoset co-curing

This work had four primary objectives:1. Identify the influential parameters during epoxy curing.2. Quantify the effect of measured process variability on curing.3. Propose manufacturing concepts for cure gradients desirable for co-curing.4. Demonstrate the influence of initial degree of cure on thermoplastic-thermoset co-curing.The most influential sources of variability in composite processing were determined by sensitivity analyses using coupled heat transfer and cure kinetics models. The analyses showed, that in the standard aerospace case considered, cure temperature has the most influence and diffusion limiting cure kinetic effects become highly influential post vitrification.To demonstrate the effect a source of process variability can have, calorimeter measurements from industrial scale ovens and autoclaves were used as inputs to a numerical model. It was shown that with the higher heat transfer coefficients in the autoclaves, spatial variability in thermal conditions was less influential. However, this effect was counteracted by the greater variability in the autoclaves, resulting in comparable repeatability between the two vessel types.Combinations of tool material, tool thickness and heat transfer coefficient were explored for maximising part stiffness while retaining bonding surface reactivity for co-curing. A thick, thermally diffusive tool for the bonding surface and a thin, low diffusivity tool elsewhere, in an out-of-autoclave environment was proposed.The effect of initial degree of cure on thermoplastic-thermoset co-curing was investigated at the laminate level. A diffusion model was derived from in-situ measurements of interdiffusion between polyetherimide and a model epoxy system. The model predicted that any increase in initial degree of cure decreased the interaction across the interface. This was supported by mechanical test results and interphase thickness measurements. The results indicated that unlike conventional co-curing, the manufacturing efficiency benefits from increasing the initial degree of cure cannot justify the significant decrease in bond strength

Power V. Threhsold: Near-Channel Morphology Controls Sediment Rating Curve Shape in Coastal Redwood Watersheds

River sediment is one of the most pervasive pollutants in the world. Excess amounts of fine sediment can reduce water quality, damage stream ecosystems, and harm aquatic life. Both natural and human-caused processes can add sediment to a river, such as tectonic uplift, landslides, and timber harvesting. Therefore, it is important to understand how fine sediment enters and moves through a rive system to inform policymakers and land-managers on effective ecosystem management. In this study, we determined how the relationship between river flow and suspended sediment changed among watersheds along the North Coast of California. We found a rise in suspended sediment concentration at median flows following extreme timber harvesting. Additionally, our results indicate that river flow and suspended sediment relationships are influenced by timber harvest activity, tectonic uplift, rainfall patterns, and near-channel environments. These results support previous findings that extreme land disturbance in a watershed, be it natural or human-caused, can change river flow and suspended sediment relationships. Our results suggest that policymakers and land-managers should take into account tectonic uplift when making regulation and should prioritize protecting near-channel environments