Reducing Noise in Automatic Transmission

The efficiency of an automobile increases as its running torque increases. This is an avenue for improving fuel economy that is actively being pursued. However, transmissions running at higher torques produce an unacceptable amount of noise, vibration, and harshness (NVH). NVH occurs most visibly as a result of the vehicle’s friction clutch behavior. At present, machines capable of testing this behavior exist (MTM machine and LVFA rig) but are very expensive in terms of time, space, and production cost. The goal of this project is to produce a cost-effective machine in which friction clutch behavior can be analyzed in a laboratory setting. Due to the complex nature of this project, multiple teams will be working to refine and improve the instrument over time. The first iteration of the machine produced by a previous design team was very limited in its ability to produce data efficiently. This design team took on the challenge of automating data collection for the load cell and thermocouple installed by the previous team, as well as implementing automated instrumentation capable of measuring motor torque and speed. The new instrumentation of the machine is illustrated below, with the measurements of torque, load, speed, and temperature being collected by an analog data acquisition system. The machine is now capable of simultaneously recording these values, producing results such as the graph shown below. In addition to the sensor additions, the team made structural modifications to the machine to accommodate the torque sensor assembly.https://scholarscompass.vcu.edu/capstone/1211/thumbnail.jp

Quantification of Model-Form, Predictive, and Parametric Uncertainties in Simulation-Based Design

Traditional uncertainty quantification techniques in simulation-based analysis and design focus upon on the quantification of parametric uncertainties-inherent natural variations of the input variables. This is done by developing a representation of the uncertainties in the parameters and then efficiently propagating this information through the modeling process to develop distributions or metrics regarding the output responses of interest. However, in problems with complex or newer modeling methodologies, the variabilities induced by the modeling process itself-known collectively as model-form and predictive uncertainty-can become a significant, if not greater source of uncertainty to the problem. As such, for efficient and accurate uncertainty measurements, it is necessary to consider the effects of these two additional forms of uncertainty along with the inherent parametric uncertainty. However, current methods utilized for parametric uncertainty quantification are not necessarily viable or applicable to quantify model-form or predictive uncertainties. Additionally, the quantification of these two additional forms of uncertainty can require the introduction of additional data into the problem-such as experimental data-which might not be available for particular designs and configurations, especially in the early design-stage. As such, methods must be developed for the efficient quantification of uncertainties from all sources, as well as from all permutations of sources to handle problems where a full array of input data is unavailable. This work develops and applies methods for the quantification of these uncertainties with specific application to the simulation-based analysis of aeroelastic structures

Quantifying the latitudinal representivity of in situ solar wind observations

Advanced space-weather forecasting relies on the ability to accurately predict near-Earth solar wind conditions. For this purpose, physics-based, global numerical models of the solar wind are initialized with photospheric magnetic field and coronagraph observations, but no further observation constraints are imposed between the upper corona and Earth orbit. Data assimilation (DA) of the available in situ solar wind observations into the models could potentially provide additional constraints, improving solar wind reconstructions, and forecasts. However, in order to effectively combine the model and observations, it is necessary to quantify the error introduced by assuming point measurements are representative of the model state. In particular, the range of heliographic latitudes over which in situ solar wind speed measurements are representative is of primary importance, but particularly difficult to assess from observations alone. In this study we use 40+ years of observation-driven solar wind model results to assess two related properties: the latitudinal representivity error introduced by assuming the solar wind speed measured at a given latitude is the same as that at the heliographic equator, and the range of latitudes over which a solar wind measurement should influence the model state, referred to as the observational localisation. These values are quantified for future use in solar wind DA schemes as a function of solar cycle phase, measurement latitude, and error tolerance. In general, we find that in situ solar wind speed measurements near the ecliptic plane at solar minimum are extremely localised, being similar over only 1° or 2° of latitude. In the uniform polar fast wind above approximately 40° latitude at solar minimum, the latitudinal representivity error drops. At solar maximum, the increased variability of the solar wind speed at high latitudes means that the latitudinal representivity error increases at the poles, though becomes greater in the ecliptic, as long as moderate speed errors can be tolerated. The heliospheric magnetic field and solar wind density and temperature show very similar behaviour

Basic Sciences Study Guide

This thesis is the beginning of a study guide to be completed for Pacific University students that are intending on taking Part I - Basic Sciences for the National Board of Examiners in Optometry. The sections covered in this section include Neuroscience, Biochemistry, Physiology and Psychology. It presents up-to-date, consistently formatted information that was compiled for, and folIows directly along with, the required topics for Part X of the board exams and it provides an alternative resource to the Berkeley Guide. The subjects indicated for Part I but not covered within this thesis will be compiled by students in following years