Indenture, Marshall County, MS, 5 March 1855

https://egrove.olemiss.edu/aldrichcorr_c/1100/thumbnail.jp

Calculus: An Integrated Approach

This is a draft of a self-published digital textbook “Calculus: An Integrated Approach” by Matt Cathey and Joseph Spivey. The textbook covers a two-semester calculus sequence for Wofford College. The text is freely available for use under the terms of the creative commons copyright, found in each of the textbook files. The free software application Wolfram CDFPlayer is required to read the textbook; it can be downloaded here: http://www.wolfram.com/cdf-player/. The complete, up-to-date version of the text can be found here: http://digitalcommons.wofford.edu/facultybooks/1/. The authors welcome questions, comments, or suggestions. Our email addresses are [email protected] and [email protected]. The version of the book with which this README file was downloaded was released August 29, 2018.https://digitalcommons.wofford.edu/facultybooks/1000/thumbnail.jp

Mars Ascent Vehicle Test Requirements and Terrestrial Validation

The Mars robotic sample return mission has been a potential flagship mission for NASA s science mission directorate for decades. The Mars Exploration Program and the planetary science decadal survey have highlighted both the science return of the Mars Sample Return mission, but also the need for risk reduction through technology development. One of the critical elements of the MSR mission is the Mars Ascent Vehicle, which must launch the sample from the surface of Mars and place it into low Mars orbit. The MAV has significant challenges to overcome due to the Martian environments and the Entry Descent and Landing system constraints. Launch vehicles typically have a relatively low success probability for early flights, and a thorough system level validation is warranted. The MAV flight environments are challenging and in some cases impossible to replicate terrestrially. The expected MAV environments have been evaluated and a first look of potential system test options has been explored. The terrestrial flight requirements and potential validation options are presented herein

Transition from no-ELM response to pellet ELM triggering during pedestal build-up—insights from extended MHD simulations

Pellet edge localized mode (ELM) triggering is a well-established scheme for decreasing the time between two successive ELM crashes below its natural value. Reliable ELM pacing has been demonstrated experimentally in several devices, increasing the ELM frequency considerably. However, it was also shown that the frequency cannot be increased arbitrarily due to a so-called lag-time. During this time, after a preceding natural or triggered ELM crash, neither a natural ELM crash occurs nor is it possible to trigger an ELM crash by pellet injection. For this article, pellet ELM triggering simulations are advanced beyond previous studies in two ways. Firstly, realistic E B and diamagnetic background flows are included. And secondly, the pellet is injected at different stages of the pedestal build-up. This allows us to recover the lag time for the first time in simulations and investigate it in detail. A series of nonlinear extended MHD simulations is performed to investigate the plasma dynamics resulting from an injection at different time points during the pedestal build-up. The experimentally observed lag-time is qualitatively reproduced. In particular, a sharp transition is observed between the regime where no ELMs can be triggered and the regime where pellet injection causes an ELM crash. Via variations of pellet parameters and injection time, the two regimes are studied and compared in detail, revealing pronounced differences in the nonlinear dynamics. The toroidal mode spectrum is significantly broader when an ELM crash is triggered, enhancing the stochasticity and therefore also the losses of thermal energy along magnetic field lines. In the heat fluxes to the divertor targets, pronounced toroidal asymmetries are observed. In the case of high injection velocities leading to deep penetration, the excitation of core modes like the 2/1 neoclassical tearing mode is also observed

Investigation of Transient Plasma Ignition

41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 10 - 13 July 2005, Tucson, ArizonaReduction of auxiliary oxygen amounts currently used in Pulse Detonation Engines (PDEs) is necessary to compete with existing Ramjet technologies. This paper investigates a Transient Plasma Ignition (TPI) system and finds that this technology enables the complete removal of any auxiliary oxygen requirements of current PDE systems. TPI was tested and compared with a traditional capacitive discharge spark ignition system within ethylene/air mixtures under dynamic fill conditions. Successful operation was achieved at up-to 40Hz repetition rates. Ignition delay times, Deflagration-to-Detonation transition (DDT) distances and DDT times, detonation wave speeds, and detonation initiation success rates were measured and analyzed for various mass flow rates, for various ethylene-air mixtures, and for various lengths of turbulence generating Schelkhin spirals. A transient plasma dual- electrode concept was also investigated and analyzed. Results show that TPI system is more effective than conventional spark ignition systems. The TPI system shows near 20% improvements to DDT distances and up-to 2.5 reduction factor in DDT times. In addition, at high flow rates, where the flames normally extinguish when employing the spark ignition system, the TPI system was able to ignite mixtures and effectively initiate detonation waves. Detonation initiation success rates greater than 94% were obtained at cycle frequencies of up-to 40Hz. Further work is required to discern the TPI system sensitiv i ty to back pressures; additional instrumentation is requi red to determine axial variations in equivalence ratio