1,368 research outputs found
A gyroscope calibration analysis for the Gamma Ray Observatory (GRO)
Current documentation and software do not adequately address the calculation and use of the optimal weight matrices involved in calibrating inertial reference units (IRU). Several facets of the GRO IRU calibration as it relates to the bias and misalignment weighting matrices are investigated. The physical meaning and use of the bias and misalignment weight matrices in IRU calibration are examined. The relation of the weighting and the final biases, misalignments, and their corrections are pursued. Methods for determining reliable, realistic weighting matrices to be used in the GRO IRU calibration (IRUCAL) utility are determined. Possible correlations among observation uncertainties are also explored. For the undetermined case where the maneuvers are insufficient to identify all calibration parameters, the weighting matrices allow as much information as possible to be extracted from the measurements. Finally, applicable simulated flight data are used, incorporating the appropriate calibration maneuvers, to test the weighting matrices in the IRUCAL utility, and examine correlation effects
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Integrated Dynamic Facade Control with an Agent-based Architecture for Commercial Buildings
Dynamic façades have significant technical potential to minimize heating, cooling, and lighting energy use and peak electric demand in the perimeter zone of commercial buildings, but the performance of these systems is reliant on being able to balance complex trade-offs between solar control, daylight admission, comfort, and view over the life of the installation. As the context for controllable energy-efficiency technologies grows more complex with the increased use of intermittent renewable energy resources on the grid, it has become increasingly important to look ahead towards more advanced approaches to integrated systems control in order to achieve optimum life-cycle performance at a lower cost. This study examines the feasibility of a model predictive control system for low-cost autonomous dynamic façades. A system architecture designed around lightweight, simple agents is proposed. The architecture accommodates whole building and grid level demands through its modular, hierarchical approach. Automatically-generated models for computing window heat gains, daylight illuminance, and discomfort glare are described. The open source Modelica and JModelica software tools were used to determine the optimum state of control given inputs of window heat gains and lighting loads for a 24-hour optimization horizon. Penalty functions for glare and view/ daylight quality were implemented as constraints. The control system was tested on a low-power controller (1.4 GHz single core with 2 GB of RAM) to evaluate feasibility. The target platform is a low-cost ($35/unit) embedded controller with 1.2 GHz dual-core cpu and 1 GB of RAM. Configuration and commissioning of the curtainwall unit was designed to be largely plug and play with minimal inputs required by the manufacturer through a web-based user interface. An example application was used to demonstrate optimal control of a three-zone electrochromic window for a south-facing zone. The overall approach was deemed to be promising. Further engineering is required to enable scalable, turnkey solutions
Professional contributions of Massachusetts School of Art to the enrichment of art education
Thesis (Ed.M.)--Boston University This item was digitized by the Internet Archive
Improving collaborative practice to address offender mental health: criminal justice and mental health service professionals’ attitudes towards interagency training, current training needs and constraints,
Background Professionals from the mental health and criminal justice system must collaborative effectively to address offender mental health but interprofessional training is lacking. Pedagogical frameworks are required to support the development of training in this new area. Aim To inform this framework this paper explores the readiness of professionals towards interprofessional training and demographic differences in these. It explores expectations of interprofessional training, perceived obstacles to collaborative working, interprofessional training needs and challenges facing delivery. Method A concurrent mixed methods approach collected data from professionals attending a crossing boundaries interprofessional workshop. Data was collected through a combination of the RIPLS questionnaire (n=52), free text questions (n=52) and focus groups (n=6). Findings and Conclusions Mental health and criminal justice professionals’ attitudes towards interprofessional learning were positive (x=17.81; n=43). They did not see their own service as insular (x =4.02; n=44) and reported strong person centredness (x= 6.07; n=43). This suggests professionals are open to the introduction and implementation of future interprofessional training. There were no significant demographic differences in these attitudes. Professionals raised a range of generic curriculum and educator mechanisms in the development of future interprofessional training suggesting the transfer of pedagogical frameworks from established interprofessional programmes into this new arena is feasible. Context specific factors such offender national policy agendas and the challenges of user involvement using mentally ill offenders must be taken into account. Greater clarity on multi versus interprofessional training is still required with this group of professionals. Key words: mental health, offenders, criminal justice, interprofessional training
The Greater Boston Housing Report Card 2013: What Follows The Housing Recovery?
This report is the 11th in the series of annual "Greater Boston Housing Report Cards," the first of which appeared in 2002 at a time when housing prices in the region were skyrocketing. In the course of this series, we have reported on the local housing bubble from 2000 through 2005, during which time home prices appreciated at annual double-digit rates; the retreat in home prices that begain in 2006; and then the beginning of a housing recovery in 2010. Like past report cards, this 2013 report probes Greater Boston's housing landscape, keeping tabs on housing construction, home prices, and rents. We have analyzed the relationship between the region's economy, demography, and housing, and we have kept track of federal, state and local government policies that affect the region's housing market. This report also includes a new analysis of local zoning regulations in Greater Boston communities because of the critical role zoning can play, particularly in the development - or lack of developmeent - of multifamily housing. The 2013 Report Card attempts to answer six questions about Greater Boston's housing market and its effect on the region's well-being: 1. What are the most recent trends in home sales, housing production, and foreclosures? 2. What does the future trajectory of home prices and rents look like? 3. Given current economic conditions, is another housing bubble on the horizon? 4. Given the changing demographics and economic health of Greater Boston, have we begun to build appropriate new housing stock to meet expected demand and to help moderate furure price and rent hikes? 5. Do we still face zoning constraints at the local level that hinder the production of an appropriate housing stock for the region? 6. What roles are the federal government and the Commonwealth playing in the housing market today
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Pascalammetry with operando microbattery probes: Sensing high stress in solid-state batteries.
Energy storage science calls for techniques to elucidate ion transport over a range of conditions and scales. We introduce a new technique, pascalammetry, in which stress is applied to a solid-state electrochemical device and induced faradaic current transients are measured and analyzed. Stress-step pascalammetry measurements are performed on operando microbattery probes (Li2O/Li/W) and Si cathodes, revealing stress-assisted Li+ diffusion. We show how non-Cottrellian lithium diffusional kinetics indicates stress, a prelude to battery degradation. An analytical solution to a diffusion/activation equation describes this stress signature, with spatiotemporal characteristics distinct from Cottrell's classic solution for unstressed systems. These findings create an unprecedented opportunity for quantitative detection of stress in solid-state batteries through the current signature. Generally, pascalammetry offers a powerful new approach to study stress-related phenomena in any solid-state electrochemical system
Younger adolescents’ perceptions of physical activity, exergaming, and virtual reality:qualitative intervention development study
Background. Novel strategies to promote physical activity (PA) in adolescence are required. The vEngage study aims to test whether a virtual reality (VR) exergaming intervention can engage younger adolescents (13-15 year old) with physical activity.
Objective: This study aimed to gather adolescents’ views of using VR to encourage PA and identify the key features they would like to see in a VR exergaming intervention via interviews.
Methods: Participants were recruited through two schools in London, UK. Semi-structured interviews were conducted with adolescents about their views on PA and what might work to increase PA, technology, knowledge and experience of VR, and desired features in a VR exergaming intervention. Data were analysed using Framework Analysis.
Results: 31 13-15 year olds (58% female, 62% from non-white ethnicities) participated in this interview study. The vast majority had no awareness of government PA recommendations, but felt they should be more thoroughly informed. All participants were positive about the use of VR in PA promotion. Rewards, increasing challenges and a social/multiplayer aspect were identified by participants as crucial aspects to include in a VR exercise game. Barriers were related to cost of high-end systems. Being able to exercise at home was very appealing. VR exergaming was viewed as a way to overcome multiple perceived social and cultural barriers to PA, particularly for girls.
Conclusions: Key elements that should be incorporated into a VR for health intervention were identified and described. These also included the use of rewards, novelty and enjoyment in immersive game play, multi-player options, real-world elements, as well as continual updates and new challenge levels. The use of VR to promote PA in adolescents is promising, but some barriers were raised
Optimisation of extraction and sludge dewatering efficiencies of bio-flocculants extracted from Abelmoschus esculentus (okra)
The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25–90 °C), time (0.25–5 h), solvent loading (0.5–5 w/w) and agitation speed (0–225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69–3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process
Influence of vegetation on SMOS mission retrievals
International audienceUsing the proposed Soil Moisture and Ocean Salinity (SMOS) mission as a case study, this paper investigates how the presence and nature of vegetation influence the values of geophysical variables retrieved from multi-angle microwave radiometer observations. Synthetic microwave brightness temperatures were generated using a model for the coherent propagation of electromagnetic radiation through a stratified medium applied to account simultaneously for the emission from both the soil and any vegetation canopy present. The synthetic data were calculated at the look-angles proposed for the SMOS mission for three different soil-moisture states (wet, medium wet and dry) and four different vegetation covers (nominally grass, crop, shrub and forest). A retrieval mimicking that proposed for SMOS was then used to retrieve soil moisture, vegetation water content and effective temperature for each set of synthetic observations. For the case of a bare soil with a uniform profile, the simpler Fresnel model proposed for use with SMOS gave identical estimates of brightness temperatures to the coherent model. However, to retrieve accurate geophysical parameters in the presence of vegetation, the opacity coefficient (one of two parameters used to describe the effect of vegetation on emission from the soil surface) used within the SMOS retrieval algorithm needed to be a function of look-angle, soil-moisture status, and vegetation cover. The effect of errors in the initial specification of the vegetation parameters within the coherent model was explored by imposing random errors in the values of these parameters before generating synthetic data and evaluating the errors in the geophysical parameters retrieved. Random errors of 10% result in systematic errors (up to 0.5°K, 3%, and ~0.2 kg m-2 for temperature, soil moisture, and vegetation content, respectively) and random errors (up to ~2°K, ~8%, and ~2 kg m-2 for temperature, soil moisture and vegetation content, respectively) that depend on vegetation cover and soil-moisture status. Keywords: passive microwave, soil moisture, vegetation, SMOS, retrieva
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