A mathematical model of three-dimensional flow in a scraped-surface heat exchanger

We present a simple mathematical model of fluid flow in a Scraped-Surface Heat Exchanger (SSHE). Specifically we consider steady isothermal flow of a Newtonian fluid around a periodic array of pivoted scraper blades in a channel with one stationary and one moving wall, when there is an applied pressure gradient in a direction perpendicular to the wall motion. The flow is fully three-dimensional, but decomposes naturally into a two-dimensional transverse flow driven by the boundary motion and a longitudinal pressure-driven flow

Platform Precision Autopilot Overview and Mission Performance

The Platform Precision Autopilot is an instrument landing system-interfaced autopilot system, developed to enable an aircraft to repeatedly fly nearly the same trajectory hours, days, or weeks later. The Platform Precision Autopilot uses a novel design to interface with a NASA Gulfstream III jet by imitating the output of an instrument landing system approach. This technique minimizes, as much as possible, modifications to the baseline Gulfstream III jet and retains the safety features of the aircraft autopilot. The Platform Precision Autopilot requirement is to fly within a 5-m (16.4-ft) radius tube for distances to 200 km (108 nmi) in the presence of light turbulence for at least 90 percent of the time. This capability allows precise repeat-pass interferometry for the Unmanned Aerial Vehicle Synthetic Aperture Radar program, whose primary objective is to develop a miniaturized, polarimetric, L-band synthetic aperture radar. Precise navigation is achieved using an accurate differential global positioning system developed by the Jet Propulsion Laboratory. Flight-testing has demonstrated the ability of the Platform Precision Autopilot to control the aircraft within the specified tolerance greater than 90 percent of the time in the presence of aircraft system noise and nonlinearities, constant pilot throttle adjustments, and light turbulence

Constructive or Disruptive? How Active Learning Environments Shape Instructional Decision-Making

This study examined instructional shifts associated with teaching in environments optimized for active learning, including how faculty made decisions about teaching and their perceptions of how students responded to those changes. The interviews and subsequent analysis reveal a broad range of course changes, from small modifications of existing activities to large shifts towards collaborative learning, many of which emerged during the term rather than being planned in advance. The faculty discuss several factors that influenced their decisions, including prior experience, professional identity, student engagement, and perceived and realized affordances of the environments

Research and Rhetorical Purpose: Using Genre Analysis to Understand Source Use in Technical and Professional Writing

This chapter describes a pilot study of student research-based writing in a technical and professional writing course designed for college-level juniors and seniors across the curriculum; fifteen analytical research papers are coded based on the rhetorical move John Swales (1990) calls reference to previous research to increase our understanding of how students use sources to introduce, support, or compare/ contrast ideas and previous research. Student papers in this study overwhelmingly used sources to support main ideas, occasionally used sources to introduce ideas, often in the form of topic sentences, but rarely used sources to compare/ contrast ideas. The frequency of support instances and the infrequency of compare/ contrast instances may suggest students had difficulty using sources to position their research, whereas they had no trouble using source excerpts to support main ideas in their writing. Local impacts of this study included several discussions among instructors about the purpose of the analytical-report assignment in our technical and professional writing course as well as suggestions for pedagogical intervention and ongoing programmatic assessment as a result of the pilot study

The Controversy of Sunscreen Ingredients: Examining the Relationship Between Oxybenzone and Butylparaben on Stylophorum Pistillata

Abstract The basis of this proposal is to understand the relationship between select UV filters and coral bleaching and provide a framework for additional research. Coral reefs are home to a diversity of marine life and are keystones to major coastal economies around the world. Oxybenzone and butylparaben are major ingredients found in sunscreen that induces coral bleaching to major coral reefs. To alleviate the negative effects, this proposal will attempt to better understand how oxybenzone and butylparaben facilitates coral bleaching and develop an effective and environmentally fair sunscreen. The research proposed will be funded by donors to cover research, lab, rental, and transportation costs. The proposal was created by the frameworks of prior researchers and studies done previously

Simple, efficient protocols for the Pd-catalyzed cross-coupling reaction of aryl chlorides and dimethylamine

Simple and efficient procedures for the Pd-catalyzed cross-coupling reaction of aryl chlorides and dimethylamine are described. At room temperature with a strong base, t-BuXPhos is employed as the supporting ligand; at 110 °C with a weak base, XPhos is employed as the supporting ligand. In each of these cases, commercially available solutions constitute the source of the dimethylamine, and recently disclosed precatalysts constitute the source of the ligand and Pd. This work further expands the utility of these precatalysts in reactions that benefit from an easily activated source of L[subscript 1]Pd(0).National Institutes of Health (U.S.) (GM-058160)National Institutes of Health (U.S.) (Postdoctoral Fellowship GM-F32-75685)Amgen Inc.Merck & Co., Inc.Boehringer Ingelheim PharmaceuticalsMassachusetts Institute of Technology. Undergraduate Research Opportunities Program (Summer Fellowship

Motor deficits in schizophrenia quantified by nonlinear analysis of postural sway.

Motor dysfunction is a consistently reported but understudied aspect of schizophrenia. Postural sway area was examined in individuals with schizophrenia under four conditions with different amounts of visual and proprioceptive feedback: eyes open or closed and feet together or shoulder width apart. The nonlinear complexity of postural sway was assessed by detrended fluctuation analysis (DFA). The schizophrenia group (n = 27) exhibited greater sway area compared to controls (n = 37). Participants with schizophrenia showed increased sway area following the removal of visual input, while this pattern was absent in controls. Examination of DFA revealed decreased complexity of postural sway and abnormal changes in complexity upon removal of visual input in individuals with schizophrenia. Additionally, less complex postural sway was associated with increased symptom severity in participants with schizophrenia. Given the critical involvement of the cerebellum and related circuits in postural stability and sensorimotor integration, these results are consistent with growing evidence of motor, cerebellar, and sensory integration dysfunction in the disorder, and with theoretical models that implicate cerebellar deficits and more general disconnection of function in schizophrenia

Variability in antifungal and antiviral use in hospitalized children

We analyzed antifungal and antiviral prescribing among high-risk children across freestanding children’s hospitals. Antifungal and antiviral days of therapy varied across hospitals. Benchmarking antifungal and antiviral use and developing antimicrobial stewardship strategies to optimize use of these high cost agents is needed.Infect Control Hosp Epidemiol2017;38:743–746</jats:p

The China shock and employment in portuguese firms

This paper considers the effects of Chinese import competition on firm-level labor market outcomes in Portugal. We examine direct competition in the Portuguese market and indirect competition Portugal's largest export markets in Western Europe. Using rich employer-employee data matched to firm-level trade transactions, we measure the degree to which different Portuguese firms faced Chinese import competition, based on firm product mix and distribution of sales across countries. We find economically and statistically significant employment declines in firms with more exposure to Chinese competition in European export markets, but minimal effects of direct competition in Portugal. Our findings also suggest a centrally important role for Portugal's stringent labor market regulations in limiting firms' ability to adjust to competitive shocks. In our earlier sample period (1995-2000), firms have limited ability to adjust employment, hours, or wages, and the primary adjustment margin is firm exit. In the later period (2000-2007), when more flexible temporary contracts comprise a larger share of employment, we find employment reductions among more exposed firms. Those employment reductions are entirely accounted for by changes in temporary employment, with no effect on permanent employment. We expect these findings to be informative for other peripheral European countries that had specialized in labor-intensive manufacturing industries operating under inflexible labor market regimes.info:eu-repo/semantics/publishedVersio