Data Acquisition and Control Program for Chromatographic and Spectroscopic Studies

An IBMPC compatible computer was interfaced to an Ithaco 3962 lock-in-amplifier. The computer controlled the functions of the lock-in-amplifier, acquired and stored data, and allowed for real time or off-line processing of data. Computer/amplifier connection was made via RS-232-C serial interface. Programmed in Microsoft Quick BASIC, the computer assumed the role of a dedicated chromatographic integrator. This reduced the overall instrumentation expense by eliminating a dedicated chromatographic integrator. The computer program supplied much greater flexibility in control and data interpretation. To show its utility, the program was applied to a study of the infrared emission from a flame upon the introduction of hydrogen or carbon species, respectively, in the gaseous form and as contained in organic compounds. Emission was monitored at 2.7 and 4.3 /μm by an infrared radiometer

Simple Synchronous Detector for Spectroscopic Studies

Lock-in-amplifiers are used in many applications for signal processing and offer the ability to discriminate high levels of noise. While these instruments are very powerful and offer many features, they are not portable and are expensive. An economical and easy to use alternative circuit is presented which incorporates pre-amplification, reference, and synchronous detection on one circuit board. The design can be used in laboratory or process control situations where its small size and low cost are advantageous. The circuit was successfully applied to moderate and high level signals as seen in flame infrared emission detection and in a portable radiometer for rocket plume studies

Evaluation of Photodiode Arrays for Use in Rocket Plume Monitoring and Diagnostics

The spectroscopic analysis of plume emissions is a non-intrusive method which has been used to check for fatigue and possible damage throughout the pumps and other mechanisms in a rocket motor or engine. These components are made of various alloys. Knowing the composition of the alloys and for which parts they are used, one can potentially determine from the emissions in the plume which component is failing. Currently, Optical Multichannel Analyzer systems are being used which utilize charge coupled devices, cost tens of thousands of dollars, are somewhat delicate, and usually require cooling. We have developed two rugged instruments using less expensive linear photodiode arrays as detectors. A high resolution system was used to detect atomic emission lines while a low resolution system was used to detect molecular emission bands. We have also written data acquisition software and built electronic circuits to control the arrays and collect data. While NASA has used similar systems for characterization of the Space Shuttle Main Engine, the emissions from other rocket systems have not been surveyed as well. The two instruments described will be utilized to study hybrid rocket emissions at the UALR hybrid rocket facility

Study of the Amplitude of Pressure and Thrust Oscillations in a Lab-Scale Hybrid Rocket

Hybrid rockets are being studied as a potential replacement for the solid rocket boosters on the NASA space shuttle. One physical characteristic of hybrid rockets that must be understood and overcome is potentially severe pressure oscillations during combustion. Pressure oscillations inside the rocket combustion chamber lead to oscillations in the thrust of the rocket. These oscillations are damaging to potential human passengers and cargo and must be minimized. Current theories surmise that the oscillations are caused by combustion chamber geometry, oxygen feed line parameters, and/or fuel combustion characteristics. This study focuses on the role of the fuel characteristics in pressure and thrust oscillations. The standard hybrid rocket fuel is hydroxyl-terminated polybutadiene (HTPB). A fuel additive, guanidinium azo-tetrazolate (GAT), has been shown to increase thrust and impulse of the rocket when added as 15% by mass to the fuel. This study compares the amplitude of the pressure and thrust oscillations of the rocket when burning HTPB fuels and when burning GAT-added fuels. Data from several firings at oxygen flow rates from 0.018 kg/sec to 0.054 kg/sec are analyzed. Results show the GAT-added fuel combustion shows no significant increase or decrease in the amplitude of the pressure and thrust oscillations

Radiometer for the Investigation of Infrared Emissions from Flames and Rocket Plumes

A prototypical radiometer using standard one inch interference filters and a lead selenide detector was constructed for use in flame and rocket plume studies. This radiometer was designed to employ a 600 Hz chopper and chopper frequency/phase reference circuit for signal processing. Bandpass filters centered for either 2.7 mum or 4.45 mum were placed in the optical path. The passed carbon dioxide or water vapor band energy irradiated the lead selenide detector, resulting in an output voltage. This signal was then fed into a dedicated synchronous detector. The signal was then recorded by a computer system equipped with an analog-to-digital converter board. Infrared emission data was collected from two inch rocket motors and from a special burner based flame

Predictors of Long-Term Victimization After Early Pediatric Traumatic Brain Injury

Pediatric traumatic brain injuries (TBIs) adversely affect long-term functional and social outcomes. Limited research suggests children with TBI are more likely to be victimized by peers than noninjured children. Deficits in social information processing (SIP), cognitive ability, and executive functioning (EF) may contribute to increased victimization risk. This study examined rates of peer victimization/bullying in children with early TBI compared with children with orthopedic injuries (OIs) and the role of processing speed, executive function (EF), and SIP as mediators of the association of TBI and peer victimization

The end of the beginning? Taking forward local democratic renewal in the post-referendum North East.

This article draws upon the author’s commissioned research on the nature of regional governance following the 2004 Referendum in the North East on elected regional assemblies. The article aimed to both capture these views and to assess how the ‘No vote in the referendum has impacted on subsequent developments in sub-national governance. The article provides both an empirical overview of recent developments and engages with the wider conceptual debates on democratic renewal. The arguments covered in this output are aimed at both academic and practitioner audiences, and have been also disseminated at regional and national conferences

Plutonium coordination and redox chemistry with the CyMe4-BTPhen polydentate N-donor extractant ligand

Complexation of Pu(IV) with the actinide extractant CyMe4-BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline) was followed by vis-NIR spectroscopy in acetonitrile solution. The solid-state structure of the crystallized product suggests that Pu(IV) is reduced to Pu(III) upon complexation. Analysis by DFT modeling is consistent with metal-based rather than ligand-based reduction