Traveling Wave Thermoacoustic-Piezoelectric Energy Harvester: Theory and Experiment

This thesis presents a theoretical and experimental investigation of a piezoelec- tric energy harvester coupled to a traveling wave thermoacoustic engine (TWTAE). By simplifying the engine using a lumped-parameter model, the performance pa- rameters such as pressure oscillation frequency and amplitude, regenerator hot end temperature, and piezoelectric output voltage are predicted. Also, an axisymmetric finite element model of the piezoelectric energy harvester is developed, resulting in a two-part reduced-order model of the electromechanical impedance of the harvester. The predictions of the finite element model are compared with those of ANSYS finite element analysis and validated experimentally. The two-part model is utilized in a numerical analysis of the TWTAE using DeltaEC (Design Environment for Low- Amplitude ThermoAcoustic Energy Conversion). Results from pressure transducers and the piezoelectric disc attached to a physical realization of the TWTAE are com- pared with theoretical predictions of the lumped-parameter models and DeltaEC analysis. The developed theoretical techniques and experimental validation provide invaluable tools for effective design of the thermoacoustic-piezoelectric harvester

Protohistory in the Wadi Ghazzeh: a typological and technological study based on the Macdonald excavations

This study reanalyzes the material from the excavations and survey of Eann Macdonald in the Wadi Ghazzeh in 1929-30 which are published in Beth Pelet II. Each site investigated by Macdonald is discussed and analyzed in terms of the stratigraphy recorded in Beth Pelet II and of the Material remains gathered through his work that are found in the collections of the Institute of Archaeology of the University of London, the British Museum and the Ashmolean Museum. Additional information is provided through consideration of subsequent work in the region by Messrs. Perrot and Alon. Four cultural phases are distinguishable - a local ceramic Neolithic phase that is found primarily in Sites B and M, two Beer Sheba-Ghassul Chalcolithic phases in Sites D, E, 0, M, A, and B and an Early Bronze I phase in Site H. These phases are defined on the basis of the technological and typological attributes of the flaked stone and ceramic assemblages. Re-examination of the collections revealed a significant number of Egyptian and Egyptian style flints in Site H as well as the possibility that some of the pottery is a local imitation of Egyptian ceramics. Certain flaked stone artifacts in Chalcolithic contexts ay also owe their existence to Egyptian influence. The analyses are based upon a detailed study of almost 15,000 flaked stone and ceramic artifacts. The typology and technical analysis of the flaked stone assemblage, developed with the aid of statistical techniques, is the first such study conducted on protohistoric Material from Israel and should serve as a basic building block for future research. The similar development of the typology and technological analysis of the ceramic material is one of the few times prehistoric lithic analytic techniques have been adapted to ceramic studies

Effect of change in the CG CAHPS survey instrument recall period on patient experience scores on healthcare utilization

Standardized patient experience survey instruments play an important role in informing healthcare quality and process improvement. However, any changes in standardized instruments can impact the interpretation, trending, and analysis of patient reported data. This study investigates how the change in Clinician and Group Consumer Assessment of Healthcare Providers and Systems (CG CAHPS) survey recall period, from 12- to 6-months, can impact the accuracy and quality of patient experience data. This study used primary survey data on patient experience collected in 2016. Analyses included tests of proportion and t-tests for a comparison of: 1) experience ratings, and 2) administrative data to corroborate how accurately respondents report the number of visits received within the recall period. The findings indicated that respondents, on average, underestimated their usage of care based on a 12-month recall period, apart from those who reported just one visit. A shorter 6-month recall period resulted in higher accuracy in reporting the number of actual visits that occurred. Furthermore, experiential measures showed consistently higher scores across measures for Provider Communications, Staff Communications, Timely Access to Care, and Care Coordination for a 6-month recall period compared to a 12-month period. This study showed that it would be difficult to compare CG CAHPS Version 2.0 to Version 3.0 due to recall differences in experiential measures. Given that shorter recall periods tend to be associated with higher CG CAHPS ratings, healthcare stakeholders should consider bias introduced by changes of recall periods in survey instruments. Experience Framework This article is associated with the Policy & Measurement lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this lens

Estimation Of Models For Use In Model-based Statistical Sampling In Designs For Inventories.

Model-based statistical sampling (MBSS) has been introduced as a promising method for constructing stratified sample designs used in the estimation of the total cost of an inventory. The MBSS methodology uses a linear model with heteroscedastic errors to construct strata. The model parameters used in MBSS are generally unknown and must be estimated. A maximum likelihood estimation (MLE) procedure assuming normally distributed residuals has been used in the past to estimate the model. However, the data in inventories are non-normal, and the MLE approach is sensitive to deviations from the normal distribution. The effects of inventory data on the MLE procedure's estimates and the subsequent effects on the MBSS sample designs are studied. A robust estimation (RRE) procedure, which should be less sensitive to deviations from the normal distribution, is developed as an alternative estimation procedure. The effects of inventory data on the RRE procedure's estimates and the subsequent effects on the MBSS sample designs are studied as well. Conventional statistical sampling, MBSS, characteristics of inventory data, empirical support for the model, and the derivations of the MLE and RRE procedures are examined. The effects of inventory data on the estimation procedures are observed through simulations using actual and generated inventory data. The simulation results are used to determine the subsequent effects of the estimation procedures on the MBSS sample designs. Results indicate that the MLE procedure is sensitive, while the RRE procedure is less sensitive to the deviations from the normal distribution found in inventory data. Also, model estimation for low error rate inventory populations can be improved. In some instances, blind use of the MLE or the RRE procedures yielded ineffective sample designs. However, prudent use of the MLE and RRE procedures along with adequate model evaluation should produce effective MBSS designs.Ph.D.Pure SciencesStatisticsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/128031/2/8712199.pd