A Sundae Stroll

Fiction by Ronald Trent

A framework for evaluating advanced search concepts for multiple autonomous underwater vehicles (AUV) mine countermeasures (MCM)

Thesis (Nav.E. and S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, February 2001.Includes bibliographical references (leaves 113-114).Waterborne mines pose an asymmetric threat to naval forces. Their presence, whether actual or perceived, creates a low-cost yet very powerful deterrent that is notoriously dangerous and time consuming to counter. In recent years, autonomous underwater vehicles (AUV) have emerged as a viable technology for conducting underwater search, survey, and clearance operations in support of the mine countermeasures (MCM) mission. With continued advances in core technologies such as sensing, navigation, and communication, future AUV MCM operations are likely to involve many vehicles working together to enhance overall capability. Given the almost endless number of design and configuration possibilities for multiple-AUV MCM systems, it is important to understand the cost-benefit trade-offs associated with these systems. This thesis develops an analytical framework for evaluating advanced AUV MCM system concepts. The methodology is based on an existing approach for naval ship design. For the MCM application, distinct performance and effectiveness metrics are used to describe a series of AUV systems in terms of physical/performance characteristics and then to translate those characteristics into numeric values reflecting the mission-effectiveness of each system. The mission effectiveness parameters are organized into a hierarchy and weighted, using Analytical Hierarchy Process (AHP) techniques, according to the warfighter's preferences for a given operational scenario. Utility functions and modeling provide means of relating the effectiveness metrics to the system-level performance parameters. Implementation of this approach involves two computer-based models: a system model and an effectiveness model, which collectively perform the tasks just described. The evaluation framework is demonstrated using two simple case studies involving notional AUV MCM systems. The thesis conclusion discusses applications and future development potential for the evaluation model.by Trent R. Gooding.Nav.E.and S.M

Background Checks for Firearm Transfers, 2015 - Statistical Tables

Describes background checks for firearms transfers conducted in 2015 and presents estimates of firearm applications received and denied annually since the effective date of the Brady Act in 1994 through 2015. Statistical tables provide data on the number of firearm applications processed by the FBI and state and local agencies, number of applications denied, reasons for denial, and estimates of applications by jurisdiction and by each type of approval system. Findings are based on data from BJS's Firearm Inquiry Statistics program, which annually surveys state and local background checking agencies to collect information on firearm background check activity and combines this information with the FBI's National Instant Criminal Background Check System transaction data to generate national estimates.Highlights:Since the effective date of the Brady Act on February 28, 1994, through December 31, 2015, nearly 197 million applications for firearm transfers or permits were subject to background checks and more than 3 million applications (1.5%) were denied.Nearly 17 million applications for firearm transfers were received in 2015, up from an estimated 15 million in 2014.About 1.4% of the nearly 17 million applications for firearm transfers or permits in 2015 were denied: about 107,000 by the FBI and about 119,000 by state and local agencies.Among state agency reporters, denial rates in 2015 were 3.0% for purchase permits, 1.5% for instant checks, 1.1% for other approval checks, and 1.1% for exempt carry permits.Local agencies denied 4.2% of applications for purchase permit checks and 1.1% of applications for exempt carry permits

The Binary White Dwarf LHS 3236

The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 +/- 0.25 pc and a tangential velocity of 98 km/s, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0-year period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M_solar; also possible, is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M_solar. In either case, the cooling ages of the stars are ~3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66--1.84 M_solar) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.Comment: Accepted for the Astrophysical Journa

The role of biomechanical parameters in upper-extremity musculoskeletal pain experienced by trombonists

There is a paucity of scientific and pedagogical literature regarding biomechanical factors, including posture, balance and musculoskeletal kinetics, in trombonists. Few published guides address posture, most doing so in superficial manner, offering direction on holding the instrument, hand position and instrument angle, without evidence base. Low brass players report a significant prevalence of playing-related musculoskeletal problems, with left upper extremity pain frequently reported. A body of literature is evolving which explores biomechanical parameter significance in players of string and keyboard instruments, but present literature regarding this in trombonists has been limited primarily to electromyography (EMG). This study sought to establish and compare the relevance and validity of motion-capture, EMG and ground reaction force simultaneous measurement methodology in trombone players. Biomechanical parameters demonstrating higher inter-subject variability are outlined, with the goal of establishing the more relevant measures and a more-streamlined methodology for future biomechanical study of this population. Deviation from biomechanical norms is evaluated as a potential risk factor for pain

Regulation of MYC Expression and Differential JQ1 Sensitivity in Cancer Cells

High level MYC expression is associated with almost all human cancers. JQ1, a chemical compound that inhibits MYC expression is therapeutically effective in preclinical animal models in midline carcinoma, and Burkitt’s lymphoma (BL). Here we show that JQ1 does not inhibit MYC expression to a similar extent in all tumor cells. The BL cells showed a ∼90% decrease in MYC transcription upon treatment with JQ1, however, no corresponding reduction was seen in several non-BL cells. Molecularly, these differences appear due to requirements of Brd4, the most active version of the Positive Transcription Elongation Factor B (P-TEFb) within the Super Elongation Complex (SEC), and transcription factors such as Gdown1, and MED26 and also other unknown cell specific factors. Our study demonstrates that the regulation of high levels of MYC expression in different cancer cells is driven by unique regulatory mechanisms and that such exclusive regulatory signatures in each cancer cells could be employed for targeted therapeutics

Design Study for a Low-enriched Uranium Core for the High Flux Isotope Reactor, Annual Report for FY 2007

This report documents progress made during fiscal year 2007 in studies of converting the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) fuel to low enriched uranium fuel (LEU). Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. A high volume fraction U/Mo-in-Al fuel could attain the same neutron flux performance as with the current, HEU fuel but materials considerations appear to preclude production and irradiation of such a fuel. A diffusion barrier would be required if Al is to be retained as the interstitial medium and the additional volume required for this barrier would degrade performance. Attaining the high volume fraction (55 wt. %) of U/Mo assumed in the computational study while maintaining the current fuel plate acceptance level at the fuel manufacturer is unlikely, i.e. no increase in the percentage of plates rejected for non-compliance with the fuel specification. Substitution of a zirconium alloy for Al would significantly increase the weight of the fuel element, the cost of the fuel element, and introduce an as-yet untried manufacturing process. A monolithic U-10Mo foil is the choice of LEU fuel for HFIR. Preliminary calculations indicate that with a modest increase in reactor power, the flux performance of the reactor can be maintained at the current level. A linearly-graded, radial fuel thickness profile is preferred to the arched profile currently used in HEU fuel because the LEU fuel media is a metal alloy foil rather than a powder. Developments in analysis capability and nuclear data processing techniques are underway with the goal of verifying the preliminary calculations of LEU flux performance. A conceptual study of the operational cost of an LEU fuel fabrication facility yielded the conclusion that the annual fuel cost to the HFIR would increase significantly from the current, HEU fuel cycle. Though manufacturing can be accomplished with existing technology, several engineering proof-of-principle tests would be required. The RERTR program is currently conducting a series of generic fuel qualification tests at the Advanced Test Reactor. A review of these tests and a review of the safety basis for the current, HEU fuel cycle led to the identification of a set of HFIR-specific fuel qualification tests. Much additional study is required to formulate a HFIR-specific fuel qualification plan from this set. However, one such test - creating a graded fuel profile across a flat foil - has been initiated with promising results