8,996 research outputs found
The development and calibration of a generic dynamic absorption chiller model
Although absorption cooling has been available for many years, the technology has typically been viewed as a poorly performing alternative to vapour compression refrigeration. Rising energy prices and the requirement to improve energy efficiency is however driving renewed interest in the technology, particularly within the context of combined cooling, heat and power systems (CCHP) for buildings. In order to understand the performance of absorption cooling, numerous models are available in the literature. However, the complexities involved in the thermodynamics of absorption chillers have so far restricted researchers to creating steady state or dynamic models reliant on data measurements of the internal chiller state, which require difficult-to-obtain, intrusive measurements. The pragmatic, yet fully-dynamic model described in this paper is designed to be easily calibrated using data obtained from the measurements of inflows and outflows to a chiller, without resorting to intrusive measurements. The model comprises a series of linked control volumes featuring both performance maps and lumped mass volumes, which reflect the underlying physical structure of the device. The model was developed for the ESP-r building simulation tool. This paper describes the modelling approach, theory and limitations, along with its calibration and the application of the model to a specific example
Validating a dynamic population microsimulation model: Recent experience in Australia
Available published research on microsimulation tends to focus on the results of policy simulations rather than upon validation of the models and their outputs. Dynamic population microsimulation models, which age an entire population through time for some decades, create particular validation challenges. This article outlines some of the issues that arise when attempting to validate dynamic population models, including changing behaviour, the need to align results with other aggregate âofficialâ projections, data quality and useability. Drawing on recent experience with the construction of the new Australian Population and Policy Simulation Model (APPSIM), the article discusses the techniques being used to validate this new dynamic population microsimulation model.Dynamic microsimulation, validation, model output, usability
Climatic and eustatic controls on the development of a Late Triassic source rock in the Jameson Land Basin, East Greenland
This work was undertaken as part of the continuing work of CASP in East Greenland. The sponsoring companies are thanked for their continued support of this work. Help in the field by T. Kinnaird and useful discussions with A. Whitham are gratefully acknowledged. The reviews of L. Clemmensen and an anonymous reviewer, and the input from S. Jones led to improvements to the original paper.Peer reviewedPostprin
The effects of movement breaks in the classroom on reading
The purpose of this study is to investigate the effect of an increase in physical activity in the classroom on (a) the on-task behavior of special education students and (b) the reading comprehension scores in a READ 180 classroom. The aim of this study is to identify teaching strategies that impact the behavior and academic success of students with special needs. Five sixth graders, three males and two females, with learning disabilities participated in the study. A single-subject ABAB design was used. During the baseline phases, students did independent reading and a reading comprehension assignment without movements immediately beforehand. During the intervention, students participated in a two-to-three minute movement break that incorporated spelling, vocabulary, or grammar review. Words read per minute and percentage correct on the five question comprehension assignment were recorded throughout all phases. Results indicate that students did not increase their on-task behavior or reading comprehension scores after participating in movement breaks. The student satisfaction survey suggests that students enjoyed participating in movement breaks. Further research is suggested to investigate the effects of movement-based lesson activities on the on-task behavior and reading comprehension scores of those with learning disabilities
Senior Recital:Kelly Simon, Horn
Kemp Recital Hall Saturday Afternoon November 10, 2007 2:00p.m
The Price Premium for Organic Babyfood: A Hedonic Analysis
The price premium associated with organic babyfood is estimated by applying a hedonic model to price and characteristic data for babyfood products collected in two cities: Raleigh, North Carolina, and San Jose, California. The price per ounce of babyfood is modeled as a function of a number of babyfood and store characteristics. The estimated organic price premium is generally equal to 3 cents to 4 cents per ounce. To the extent this premium reflects consumer willingness to pay to reduce pesticide exposures, it could be used to infer values for reduced dietary exposures to pesticide residues for babies.babyfood, hedonic analysis, organic foods, Demand and Price Analysis,
A poroelastic model coupled to a fluid network with applications in lung modelling
Here we develop a lung ventilation model, based a continuum poroelastic
representation of lung parenchyma and a 0D airway tree flow model. For the
poroelastic approximation we design and implement a lowest order stabilised
finite element method. This component is strongly coupled to the 0D airway tree
model. The framework is applied to a realistic lung anatomical model derived
from computed tomography data and an artificially generated airway tree to
model the conducting airway region. Numerical simulations produce
physiologically realistic solutions, and demonstrate the effect of airway
constriction and reduced tissue elasticity on ventilation, tissue stress and
alveolar pressure distribution. The key advantage of the model is the ability
to provide insight into the mutual dependence between ventilation and
deformation. This is essential when studying lung diseases, such as chronic
obstructive pulmonary disease and pulmonary fibrosis. Thus the model can be
used to form a better understanding of integrated lung mechanics in both the
healthy and diseased states
Low frequency, in-situ vibrating sample magnetometer : electrical systems and control software design
Includes bibliographical references.A low frequency vibrating sample magnetometer has been built to measure the in-situ properties of ferromagnetic catalysts. The instrument allows measurements to be taken during an experimental catalyst test run (in-situ). The vibration is performed by a motor crank arrangement frequency of 2 Hz. The software designed to control the instrument and the reaction was written in Lab View which enabled a rapid prototyping approach. This thesis focuses on the software and electrical systems of the setup. Results of research conducted using this system are published separately however this document shows the relationship between the magnetic saturation and remnance and the mass of ferromagnetic material present in the reference material as well as the effect of temperature on this material
Finding âInterestingâ Correlations in Multi-Faceted Personal Informatics Systems
Personal Informatics (PI) systems are capable of uncovering interesting insights about their users by identifying statistical correlations in multi-faceted data. However, they often produce an overwhelming quantity of information. We explore the feasibility of automatically filtering correlational information, based on its interest to users. We analyze usersâ subjective ratings of correlations within their data to gain a deeper understanding of the factors that contribute to usersâ interest. We then use this understanding to identify candidate measures for information filtering, which can be applied without input from the user. Finally, we test the predictive power of these measures. Our main findings reveal that users in our study valued the Surprisingness and Utility of correlational information above other factors
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