1956: Abilene Christian College Bible Lectures - Full Text

Golden Anniversary Edition featuring the theme THEY SHALL ALL BE TAUGHT OF GOD Price: $3.50 FIRM FOUNDATION PUBLISHING HOUSE Box 77 Austin, Texa

A study of a two-frequency NMR maser

Typescript (photocopy).A unique NMR maser has been developed and operated which oscillates continuously and simultaneously at two different Larmor frequencies. The nuclear spin systems consist of hydrogen and fluorine nuclei provided by a 10 cm('3) sample of benzene and hexafluorobenzene. Overhauser pumping is used to invert and enhance the two nuclear magnetizations. A magnetic field of 11.74 gauss is used so that the oscillation frequencies are 50.00 kHz (the hydrogen nuclei Larmor frequency at 11.74 g) and 47.04 kHz (the fluorine nuclei Larmor frequency). The oscillations occur in a tuned circuit which resonates at the two frequencies. The frequency stability as a function of averaging time of the maser was measured by a period counting technique which uses one oscillation frequency as a clock against which the other oscillation frequency is determined. This method is shown to yield (in principle) the stability that would be directly measured (using a perfect clock) for the maser operating in an absolutely constant magnetic field

A study of a two-frequency NMR maser

Typescript (photocopy).A unique NMR maser has been developed and operated which oscillates continuously and simultaneously at two different Larmor frequencies. The nuclear spin systems consist of hydrogen and fluorine nuclei provided by a 10 cm('3) sample of benzene and hexafluorobenzene. Overhauser pumping is used to invert and enhance the two nuclear magnetizations. A magnetic field of 11.74 gauss is used so that the oscillation frequencies are 50.00 kHz (the hydrogen nuclei Larmor frequency at 11.74 g) and 47.04 kHz (the fluorine nuclei Larmor frequency). The oscillations occur in a tuned circuit which resonates at the two frequencies. The frequency stability as a function of averaging time of the maser was measured by a period counting technique which uses one oscillation frequency as a clock against which the other oscillation frequency is determined. This method is shown to yield (in principle) the stability that would be directly measured (using a perfect clock) for the maser operating in an absolutely constant magnetic field

2009 BBEST Sabine and Neches Rivers and Sabine Lake Bay environmental flows recommendations report

Senate Bill 3 (SB3) of the 80th Texas Legislature established a process for the development and implementation of environmental flow standards applicable to major river basins and estuarine systems across the State of Texas. As summarized in Figure 1.1.1 (see Section 1.1.4), this process began with selection of the Environmental Flows Advisory Group (EFAG) and reaches an interim conclusion for each river basin and associated estuarine system upon Texas Commission on Environmental Quality (TCEQ) adoption of rules implementing environmental flow standards. This Environmental Flows Recommendations Report is the primary deliverable of the Nueces River and Corpus Christi and Baffin Bays Basin and Bay Expert Science Team (Nueces BBEST) and is timely submitted in the midst of the SB3 environmental flows process to serve as a useful technical resource

Effect of Shielding Conductivity on Magnetic Induction Tomographic Security Imagery

Recently, there has been a rapid rise in experiential research investigating the potential of exploiting magnetic induction tomographic techniques to improve security, develop industry, and enhance medicine. This investigation explored the functionality of a fully automated magnetic imaging system able to capture 2-D images of featured metallic objects in unshielded and beneath conductively shielded configurations. Images were captured using a programmable x-y stage that moved objects relative to, and when magnetically coupled with, a stationary induction sensor coil; thus, position-resolved measurements of variations in sensor inductance (L) clearly defined the features of conductive objects and distinguished different material types. This investigation concentrated first on exploring the system's ability to distinguish different metals from images that represented proportional conductivity maps, and second, on the effects that a range of shielding conductivity materials had on resultant image quality and resolution. This investigation has provided a greater understanding when assessing potential capability improvements that magnetic induction tomographic techniques could offer a security and/or industrial application