Development of a Low-Noise High Common-Mode-Rejection Instrumentation Amplifier

Several previously used instrumentation amplifier circuits were examined to find limitations and possibilities for improvement. One general configuration is analyzed in detail, and methods for improvement are enumerated. An improved amplifier circuit is described and analyzed with respect to common mode rejection and noise. Experimental data are presented showing good agreement between calculated and measured common mode rejection ratio and equivalent noise resistance. The amplifier is shown to be capable of common mode rejection in excess of 140 db for a trimmed circuit at frequencies below 100 Hz and equivalent white noise below 3.0 nv/square root of Hz above 1000 Hz

Design of a Torque Current Generator for Strapdown Gyroscopes

The design, analysis, and experimental evaluation of an optimum performance torque current generator for use with strapdown gyroscopes, is presented. Among the criteria used to evaluate the design were the following: (1) steady-state accuracy; (2) margins of stability against self-oscillation; (3) temperature variations; (4) aging; (5) static errors drift errors, and transient errors, (6) classical frequency and time domain characteristics; and (7) the equivalent noise at the input of the comparater operational amplifier. The DC feedback loop of the torque current generator was approximated as a second-order system. Stability calculations for gain margins are discussed. Circuit diagrams are shown and block diagrams showing the implementation of the torque current generator are discussed

Development of a digital electronic rebalance loop for a dry tuned-rotor two degree-of-freedom gyroscope

Digital electronic rebalance loops were designed and implemented in brassboard form to capture both X and Y axes of the Kearfott Gyroflex. The loops were width-modulated binary types using a 614.4 kHz keying signal and a 2.4 kHz sample frequency. The loops were designed for a torquing rate of 2 deg/sec (70.6 mA torquing current) and a data resolution of 23.4 milli-arc-sec per data pulse. Design considerations, implementation details, and preliminary experimental results are presented

High-resolution width-modulated pulse rebalance electronics for strapdown gyroscopes and accelerometers

Three different rebalance electronic loops were designed, implemented, and evaluated. The loops were width-modulated binary types using a 614.4 kHz keying signal; they were developed to accommodate the following three inertial sensors with the indicated resolution values: (1) Kearfott 2412 accelerometer - resolution = 260 micro-g/data pulse, (2) Honeywell GG334 gyroscope - resolution = 3.9 milli-arc-sec/data pulse, (3) Kearfott 2401-009 accelerometer - resolution = 144 milli-g/data pulse. Design theory, details of the design implementation, and experimental results for each loop are presented

Wireless, in-vessel neutron monitor for initial core-loading of advanced breeder reactors

An experimental wireless, in-vessel neutron monitor was developed to measure the reactivity of an advanced breeder reactor as the core is loaded for the first time to preclude an accidental critically incident. The environment is liquid sodium at a temperature of approx. 220 C, with negligible gamma or neutron radiation. With ultrasonic transmission of neutron data, no fundamental limitation was observed after tests at 230 C for 2000 h. The neutron sensitivity was approx. 1 count/s-nv, and the potential data transmission rate was approx. 10,000 counts/s

Adaptive Synaptogenesis Constructs Neural Codes That Benefit Discrimination

Intelligent organisms face a variety of tasks requiring the acquisition of expertise within a specific domain, including the ability to discriminate between a large number of similar patterns. From an energy-efficiency perspective, effective discrimination requires a prudent allocation of neural resources with more frequent patterns and their variants being represented with greater precision. In this work, we demonstrate a biologically plausible means of constructing a single-layer neural network that adaptively (i.e., without supervision) meets this criterion. Specifically, the adaptive algorithm includes synaptogenesis, synaptic shedding, and bi-directional synaptic weight modification to produce a network with outputs (i.e. neural codes) that represent input patterns proportional to the frequency of related patterns. In addition to pattern frequency, the correlational structure of the input environment also affects allocation of neural resources. The combined synaptic modification mechanisms provide an explanation of neuron allocation in the case of self-taught experts

Protein Engineering Potential Inhibitor of Detrimental Immune Responses

On the surface of immune cells, class II major histocompatibility complex proteins (MHCII) present antigenic peptides for CD4+ T cell recognition, which initiate a variety of antigen-specific immune responses such as antibody response or cytotoxic T cell activation. In people with with auto-immune diseases including but not limited to type 1 diabetes, multiple sclerosis, and rheumatoid arthritis, detrimental immune responses occur after the presentation of antigenic peptides. A single-chain, minimal MHCII (scm-MHCII) has been designed to retain its function as an antigen-presenting protein with a simplified structure that can be easily produced and manipulated in a laboratory by recombinant microbial expression. By applying directed evolution and selection for protein stability quantified using yeast surface display (YSD), we have engineered a mutant library which may contain highly stable mutants capable of functioning as a highly specific inhibitor of T cell-mediated immune responses with the potential to be applied to treating a variety auto-immune diseases

Best Brief, 2007 Intrastate Moot Court Competition

ATHENS, Ga. - The University of Georgia School of Law recently captured the 2007 Intrastate Moot Court Championship when it bested a team from Georgia State University for the win. Every year, each law school in the state fields two teams in the competition. Second-year students Tully T. Blalock, Cameron D. Hawkins and David L. Pilson comprised the winning team, while another Georgia Law team of second-year students James E. Butler, Rachel D. Horton and Catherine D. Runion advanced to the semifinal round. Both groups were coached by third-year students Lauren L. Mock and Glenn T. Singleton. The winning team also took home the Best Brief Award. This is the second year in a row where Georgia Law has won both the overall title and Best Brief Award in this tournament