2,098 research outputs found
Laser angle sensor development
Electrical and optical parameters were developed for a two axis (pitch/roll) laser angle sensor. The laser source and detector were mounted in the plenum above the model. Two axis optical distortion measurements of flow characteristics in a 0.3 transonic cryogenic tunnel were made with a shearing interferometer. The measurement results provide a basis for estimating the optical parameters of the laser angle sensor. Experimental and analytical information was generated on model windows to cover the reflector. A two axis breadboard was assembled to evaluate different measurement concepts. The measurement results were used to develop a preliminary design of a laser angle sensor. Schematics and expected performance specifications are included
Laser angle sensor
A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures
Laser angle measurement system
The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given
Coriolis force in Geophysics: an elementary introduction and examples
We show how Geophysics may illustrate and thus improve classical Mechanics
lectures concerning the study of Coriolis force effects. We are then interested
in atmospheric as well as oceanic phenomena we are familiar with, and are for
that reason of pedagogical and practical interest. Our aim is to model them in
a very simple way to bring out the physical phenomena that are involved.Comment: Accepted for publication in European Journal of Physic
A qualitative study into the use of formal services for dementia by carers from culturally and linguistically diverse (CALD) communities.
BACKGROUND: People with dementia and their family carers need to be able to access formal services in the community to help maintain their wellbeing and independence. While knowing about and navigating one's way through service systems is difficult for most people, it is particularly difficult for people from culturally and linguistically diverse (CALD) communities. This study addresses a lack of literature on the use of formal services for dementia by people from CALD backgrounds by examining the experiences and perceptions of dementia caregiving within four CALD communities - Italian, Chinese, Spanish and Arabic-speaking - in south western Sydney, Australia. METHODS: The study used a qualitative design and the methods included focus groups with family carers and one-to-one interviews with bilingual/bicultural community workers, bilingual general practitioners and geriatricians. A total of 121 family carers participated in 15 focus groups and interviews were held with 60 health professionals. All fieldwork was audiotaped, transcribed and subjected to thematic analysis. RESULTS: People from CALD communities are often unfamiliar with the concept of formal services and there may be strong cultural norms about maintaining care within the family, rather than relying on external services. CALD communities often have limited knowledge of services. There is a preference for services that will allow families to keep their relative at home, for safety as well as cultural reasons, and they are particularly reluctant to use residential care. While there is a preference for ethno-specific or multicultural services, mainstream services also need to ensure they are more flexible in providing culturally appropriate care. Positive outcomes occur when ethno-specific services work in partnership with mainstream programs. Dementia service providers need to develop a trusting relationship with their local CALD communities and promote their services in a way that is understandable and culturally acceptable to members of these communities. CONCLUSIONS: While members of CALD communities may have difficulties accessing formal services, they will use them if they are culturally and linguistically appropriate and can meet their needs. There are a number of ways to improve service provision to CALD communities and the responsibility for this needs to be shared by a range of stakeholders
Generalized Rosenfeld scalings for tracer diffusivities in not-so-simple fluids: Mixtures and soft particles
Rosenfeld [Phys. Rev. A 15, 2545 (1977)] noticed that casting transport
coefficients of simple monatomic, equilibrium fluids in specific dimensionless
forms makes them approximately single-valued functions of excess entropy. This
has predictive value because, while the transport coefficients of dense fluids
are difficult to estimate from first principles, excess entropy can often be
accurately predicted from liquid-state theory. Here, we use molecular
simulations to investigate whether Rosenfeld's observation is a special case of
a more general scaling law relating mobility of particles in mixtures to excess
entropy. Specifically, we study tracer diffusivities, static structure, and
thermodynamic properties of a variety of one- and two-component model fluid
systems with either additive or non-additive interactions of the hard-sphere or
Gaussian-core form. The results of the simulations demonstrate that the effects
of mixture concentration and composition, particle-size asymmetry and
additivity, and strength of the interparticle interactions in these fluids are
consistent with an empirical scaling law relating the excess entropy to a new
dimensionless (generalized Rosenfeld) form of tracer diffusivity, which we
introduce here. The dimensionless form of the tracer diffusivity follows from
knowledge of the intermolecular potential and the transport / thermodynamic
behavior of fluids in the dilute limit. The generalized Rosenfeld scaling
requires less information, and provides more accurate predictions, than either
Enskog theory or scalings based on the pair-correlation contribution to the
excess entropy. As we show, however, it also suffers from some limitations,
especially for systems that exhibit significant decoupling of individual
component tracer diffusivities.Comment: 15 pages, 10 figure
Phylogeography of Japanese encephalitis virus:genotype is associated with climate
The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate
The Nonlinear Meissner Effect in Unconventional Superconductors
We examine the long-wavelength current response in anisotropic
superconductors and show how the field-dependence of the Meissner penetration
length can be used to detect the structure of the order parameter. Nodes in the
excitation gap lead to a nonlinear current-velocity constitutive equation at
low temperatures which is distinct for each symmetry class of the order
parameter. The effective Meissner penetration length is linear in and
exhibits a characteristic anisotropy for fields in the -plane that is
determined by the positions of the nodes in momentum space. The nonlinear
current-velocity relation also leads to an intrinsic magnetic torque for
in-plane fields that are not parallel to a nodal or antinodal direction. The
torque scales as for and has a characteristic angular
dependence. We analyze the effects of thermal excitations, impurity scattering
and geometry on the current response of a superconductor, and
discuss our results in light of recent measurements of the low-temperature
penetration length and in-plane magnetization of single-crystals of
and .Comment: 30 pages, RevTeX file with 16 postscript figures. Submitted to Phys.
Rev.
Formative peer assessment in a CSCL environment
In this case study our aim was to gain more insight in the possibilities of qualitative formative peer assessment in a computer supported collaborative learning (CSCL) environment. An approach was chosen in which peer assessment was operationalised in assessment assignments and assessment tools that were embedded in the course material. The course concerned a higher education case-based virtual seminar, in which students were asked to conduct research and write a report in small multidisciplinary teams. The assessment assignments contained the discussion of assessment criteria, the assessment of a group report of a fellow group, and writing an assessment report. A list of feedback rules was one of the assessment tools. A qualitative oriented study was conducted, focussing on the attitude of students towards peer assessment and practical use of peer assessment assignments and tools. Results showed that students’ attitude towards peer assessment was positive and that assessment assignments had added value. However, not all students fulfilled all assessment assignments. Recommendations for implementation of peer assessment in CSCL environments as well as suggestions for future research are discussed
Challenges & Rewards with an Institutional Repository
UVM Libraries launched ScholarWorks @ UVM in 2013 to collect, preserve and disseminate scholarly works of faculty, students as well as make collections, reports and other materials more discoverable and available.This institutional repository has grown to over twenty collections, comprising of student dissertations and theses, public health projects, historic botanical research, Vermont history, faculty publications and more.Challenges include varied participation across campus, impacting work flow in library positions, and adding another library service.Author’s works enjoy increased discoverability from all over the world, from low income countries to individuals that seek information without the benefit of library resources. IRs support libraries’ intellectual mission
- …
