1,359 research outputs found
A Study into Data Analysis of Varying Types of Langmuir Probes
Langmuir probes are ubiquitously used for in-situ measurements of plasma parameters. These probes have been placed on many different platforms, including experimental sounding rockets for measurements in mesosphere-lower-thermosphere, and also onboard satellites to obtain data sets over an extended period of time in the ionosphere. To accommodate such different situations, many different variations of the Langmuir probe design have been made. This thesis covers two such implementations, as well as the data analysis and issues that can arise with such instruments. The first of these implementations is a set of sweeping Langmuir probes on the Floating Potential Measurement Unit (FPMU) that is deployed on-board the International Space Station. We compare the output of NASA’s current data processing algorithm for FPMU to that of our own algorithm. This work shows how instruments degrade overtime, and how data analysis can partially work around such degradation. Our analysis also demonstrated how various environmental effects need to be accounted for to get an accurate measurement during data analysis of Langmuir probes. The second implementation considered in this thesis is a new multi-needle Langmuir probe (mNLP) design as recently flown aboard some German sounding rockets. Our work confirms that mNLP instrument shows great promise, but also cautions in its data processing algorithms which can easily lead to 50% errors unless appropriately dealt with. We then present a new way to analyze mNLP data that can bring the measurement error to within 10%
Homer and the Roland: The Shared Formular Technique, Part I
"The argument of the following article, though necessarily long and demanding, can be summarized briefly. Homer employs his noun-formulae consistently, so that the principles of their employment can be stated mathematically in the form of equations and graphs."--Introductio
Homer and the Roland: The Shared Formular Technique, Part II
A continuation of Sale's earlier article, (8/1 [1993]:87-142), on the statistical analysis applied to the study of Homer and the Song of Roland
The Coming Man From Canton : Chinese Experience in Montana (1862-1943)
The Chinese immigrants who came to Montana during the 19th and 20th centuries forged a new community. The goals of this dissertation were to create a historical and archaeological context for Chinese Experience in Montana, and to frame the interpretation of these results within a social organization framework that highlights the role of Overseas Chinese voluntary organizations such as secret societies. Archaeologists and historians have studied the Chinese in Montana for a little over two decades, though nothing comprehensive has ever been attempted to sew together the various investigations. In addition, there has been no attempt to inventory all the known Chinese archaeological sites in Montana, and how these fit into the broad patterns of history. Between first large-scale gold discovery in Montana Territory during 1862 until 1900, the Chinese engaged largely in placer-mining endeavors and represented the largest ethnic group during this period. Federal Exclusion laws, statewide boycotts, and pervasive racism deeply affected the Chinese experience in Montana, and led to the state’s abandonment by the bulk of this immigrant population in the early 20th century. In overseas communities, the Chinese immigrants relied on voluntary associations to replace the traditional modes of social organization found in China. These organizations provided mutual protection to their members, and helped to organize resistance to the legal and social racism encountered in the United States and other diaspora communities. This dissertation interprets the history and archaeology of the Chinese in Montana in a framework that highlights the role of voluntary social organizations in the success of this population
Restoring Balance – Reconstructing Indigenous Strategies in King Philip’s War
King Philip’s War (1675 – 1678) was one of several Indian Wars in 17th-century colonial America. It was also referred to as “the first Indian war. However, there had been a previous conflict known as The Pequot War (1636 – 1638). Unlike the previous war and unrelated skirmishes over the years, King Philip’s War was a regional conflict that quickly spread throughout coastal and interior Native homelands in what is now called New England. While issues that caused the war built up over decades, the war formally began on the 25th of June,1675, when a band of Pauquunaukit Wampanoag (anglicized as Pokanoket, literally, land at the clearing )attacked several isolated homesteads in the small Plymouth colony settlement of Swansea.Their leader, or Sachem, was a man named Metacom, known as Philip to the English. Metacom was the son of 8sâmeeqan (Ousamequin), more commonly known as Massasoit.He was the same Massasoit who assisted the first English settlers at Plymouth in 1620. While the war ended in Southern New England with Philip\u27s death on the 12th of August, 1676, the war continued in Northern New England until the Treaty of Casco in April of 1678. King Philip’s War was therefore not a localized event like the earlier Pequot War (1636 – 1638). The Pequot War served as an example of what the Indigenous nations faced at the hand of the English. In that war, the English made no distinction between combatants and non-combatants, as evidenced by the Connecticut and Massachusetts Colonies\u27 attack on the Pequot fortified village at Mystic on the 26th of May, 1637. The Pequot defeat may well have provided food for thought among Indigenous nations in the area, and may have catalyzed their commitment towards procuring firearms
A Pump Monitoring Approach to Irrigation Pumping Plant Performance Testing
Traditionally, irrigation pumping plants have been tested using an instantaneous appraoch, which tests performance parameters over a very short time interval. Using this method, the tester measures the necessary work and energy use parameters to calculate the desired pumping plant performance values. The primary limitation of this approach is its inability to determine the season long efficiency of an irrigation pumping plant.
A new approach to evaluating irrigation pumping plant performance is the use of pump monitoring systems which use high frequency, real-time data collection and telemetry to relay information directly from the pump to the user. This method of testing essentially conducts a continuous pumping plant performance evaluation.
Throughout a typical irrigation season, a single pumping plant typically operates at a wide range of total dynamic heads as a result of changes in operational conditions due to factors such as aquifer drawdown and irrigation demand changes. When coupled with telemetry, this approach to irrigation pumping plant testing can provide real-time feedback to the irrigator on pumping plant performance, even as the operating conditions of the system changes throughout the season.
Nearly 100 pumping years of diesel and electric pumping plant data was evaluated over four irrigation seasons using a network of these pump monitoring systems. Annual averages and trends in water pumping flow rate, cost of water per unit volume pumped, and efficiency as a percentage of the Nebraska Pumping Plant Performance Criteria, among other performance values were reported. These pumping performance values can be used to develop recommendations to producers in order to improve pumping plant performance and reduce operating costs as well as identifying the causes of pumping plant inefficiencies
Error Analysis of Multi-Needle Langmuir Probe Measurement Technique
Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation
Test of wire-gauze packed fractionating column
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1939.MIT copy bound with: Scale formation in a natural convection boiler / W. B. Keene and P. H. Schneider. 1939.Includes bibliographical references (leaves 61-62).by William A. Merritt.B.S
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