16th Annual SAMPE Student Bridge Contest: Design of a Wood Core Flax Fiber-Reinforced Composite I-Beam

The goal of this project was to demonstrate the applicability of natural composites in structural applications for objects with shorter intended life spans such as sports equipment. This was done by competing in the 16th Annual SAMPE Student Bridge Contest with a natural fiber, natural core composite I-beam in Long Beach, California on May 8th, 2013. The beam was to withstand 3,000 lbs under three-point-bending while maintaining a low weight. In order to compete, natural reinforcement fibers, natural core materials and a bonding matrix had to be identified; a beam within allowable contest dimensions had to be designed; and a feasible manufacturing process had to be developed and carried out. This report details the progression of the project and present its results by first offering some background on fiber-reinforced composite materials, their basic constituents and their manufacturing processes. It then provides some design specifications for the SAMPE Student Bridge Contest and a feasibility discussion of said specifications and potential manufacturing processes. Finally, the report will discuss the three beams made during this project, offer information on the competition beam\u27s performance and some recommendations for next year\u27s competition

Guiding Transformation: How Medical Practices Can Become Patient-Centered Medical Homes

Describes in detail eight change concepts as a guide to transforming a practice into a patient-centered medical home, including engaged leadership, quality improvement strategy, continuous and team-based healing relationships, and enhanced access

Serpentine channels: micro -- rheometers for fluid relaxation times

We propose a novel device capable of measuring the relaxation time of viscoelastic fluids as small as 1\,ms. In contrast to most rheometers, which by their very nature are concerned with producing viscometric or nearly-viscometric flows, here we make use of an elastic instability which occurs in the flow of viscoelastic fluids with curved streamlines. To calibrate the rheometer we combine simple scaling arguments with relaxation times obtained from first normal-stress difference data measured in a classical shear rheometer. As an additional check we also compare these relaxation times to those obtained from Zimm theory and good agreement is observed. Once calibrated, we show how the serpentine rheometer can be used to access smaller polymer concentrations and lower solvent viscosities where classical measurements become difficult or impossible to use due to inertial and/or resolution limitations. In the absence of calibration the serpentine channel can still be a very useful comparative or index device.Comment: accepted for for publication in Lab on a chi

Elevated Depressive Symptoms In A Community Sample Of African-Americans And Whites

This study examined demographic and psychosocial correlates of elevated depressive symptoms among African-Americans and Whites from comparable socioeconomic and neighborhood backgrounds. 851 African-Americans and 597 Whites from adjacent census tracts were interviewed using previously validated indicators of depressive symptoms, social support, religious practices and various demographic characteristics. More Whites than African-Americans reported elevated depressive symptoms and the groups also differed on several demographic variables and psychosocial variables. Employment, marital status and age were salient demographic covariates for African Americans, while income was for Whites. For both groups, social support and church attendance were inversely associated with depressive symptoms. Prayer was positively associated with depressive symptoms. Future research should explore within racial/ethnic group variations in depressive symptoms. Insights also are needed into possible changes over time in the relationship between religious variables and depressive symptoms, and how social support limits depressive symptoms in diverse populations

The mechanical response of fire ant rafts

Fire ants (Solenopsis invicta) cohesively aggregate via the formation of voluntary ant-to-ant attachments when under confinement or exposed to water. Once formed, these aggregations act as viscoelastic solids due to dynamic bond exchange between neighboring ants as demonstrated by rate-dependent mechanical response of 3D aggregations, confined in rheometers. We here investigate the mechanical response of 2D, planar ant rafts roughly as they form in nature. Specifically, we load rafts under uniaxial tension to failure, as well as to 50% strain for two cycles with various recovery times between. We do so while measuring raft reaction force (to estimate network-scale stress), as well as the networks' instantaneous velocity fields and topological damage responses to elucidate the ant-scale origins of global mechanics. The rafts display brittle-like behavior even at slow strain rates (relative to the unloaded bond detachment rate) for which Transient Network Theory predicts steady-state creep. This provides evidence that loaded ant-to-ant bonds undergo mechanosensitive bond stabilization or act as \say{catch bonds}. This is further supported by the coalescence of voids that nucleate due to biaxial stress conditions and merge due to bond dissociation. The characteristic timescales of void coalescence due to chain dissociation provide evidence that the local detachment of stretched bonds is predominantly strain- (as opposed to bond lifetime-) dependent, even at slow strain rates, implying that bond detachment rates diminish significantly under stretch. Significantly, when the voids are closed by restoring the rafts to unstressed conditions, mechanical recovery occurs, confirming the presence of concentration-dependent bond association that - combined with force-diminished dissociation - could further bolster network cohesion under certain stress states

The Santa Fe Light Cone Simulation Project: I. Confusion and the WHIM in Upcoming Sunyaev-Zel'dovich Effect Surveys

We present the first results from a new generation of simulated large sky coverage (~100 square degrees) Sunyaev-Zeldovich effect (SZE) cluster surveys using the cosmological adaptive mesh refinement N-body/hydro code Enzo. We have simulated a very large (512^3h^{-3}Mpc^3) volume with unprecedented dynamic range. We have generated simulated light cones to match the resolution and sensitivity of current and future SZE instruments. Unlike many previous studies of this type, our simulation includes unbound gas, where an appreciable fraction of the baryons in the universe reside. We have found that cluster line-of-sight overlap may be a significant issue in upcoming single-dish SZE surveys. Smaller beam surveys (~1 arcmin) have more than one massive cluster within a beam diameter 5-10% of the time, and a larger beam experiment like Planck has multiple clusters per beam 60% of the time. We explore the contribution of unresolved halos and unbound gas to the SZE signature at the maximum decrement. We find that there is a contribution from gas outside clusters of ~16% per object on average for upcoming surveys. This adds both bias and scatter to the deduced value of the integrated SZE, adding difficulty in accurately calibrating a cluster Y-M relationship. Finally, we find that in images where objects with M > 5x10^{13} M_{\odot} have had their SZE signatures removed, roughly a third of the total SZE flux still remains. This gas exists at least partially in the Warm Hot Intergalactic Medium (WHIM), and will possibly be detectable with the upcoming generation of SZE surveys.Comment: 14 pages, 13 figures, version accepted to ApJ. Major revisions mad

Finding Needles in the Right Haystack: Double Modals in Medical Consultations

In this paper we present a case study of a syntactic sociolinguistic variable that has resisted previous attempts at quantitative analysis of usage, the double modal construction of Southern United States English (e.g., You know what might could help that is losing some weight). While naturally-occurring double modals have been exceedingly rare in sociolinguistic interviews, our study represents the very first corpus investigation of double modals through a search of the right ‘haystack’: the nationwide Verilogue, Inc database of recorded and transcribed physician-patient interactions (~85 million words). As a vast source of potentially face-threatening negotiations, the Verilogue corpus provides the ideal speech situation in which to search for low frequency, non-standard syntactic features like the double modal. A quantitative analysis of the 76 tokens extracted from doctor-patient consultations in the US South revealed that double modals are favored by doctors, especially women and those with many decades of professional experience. Among patients, those not currently in employment use double modals more frequently than the employed. We interpreted these findings with reference to the literature on the pragmatics of physician-patient talk, arguing that the double modal is used to negotiate the imbalanced power dynamic of a doctor-patient consultation. In general, the greater use of double modals by doctors shows that the construction is an active part of a doctor’s repertoire for mitigating directives. Collectively, we present a complex socio-pragmatic picture of double modal use that could not be seen without a corpus of naturally-occurring speech in a potentially face-threatening speech situation