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SIGNAL PROCESSING ABOUT A DISTRIBUTED DATA ACQUISITION SYSTEMKolb, John 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Because modern data acquisition systems use digital backplanes, it is logical for more
and more data processing to be done in each Data Acquisition Unit (DAU) or even in
each module. The processing related to an analog acquisition module typically takes the
form of digital signal conditioning for range adjust, linearization and filtering. Some of
the advantages of this are discussed in this paper. The next stage is powerful processing
boards within DAUs for data reduction and third-party algorithm development. Once data
is being written to and from powerful processing modules an obvious next step is
networking and decom-less access to data. This paper discusses some of the issues related
to these types of processing.
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A NEXT GENERATION AIRCRAFT POWER MONITORING SYSTEMGrossman, Hy 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Historically, aircraft power monitoring has required the use of multiple signal conditioning functions to measure various parameters including voltage, current, frequency and phase. This information was then post processed to determine the characteristics of the 3-phase power quality on the aircraft. Recent developments in embedded DSP processors within signalconditioning systems provide the instrumentation engineer with expanded capabilities for realtime on-board power quality monitoring. Advantages include reduced space and bandwidth requirements and minimal wiring intrusion. For each phase, output data may include peak positive and negative voltages and currents, peak-to-peak, average and RMS voltages and currents, phase power (real and apparent), phase power factor, phase period (frequency), phase shift measurement from phase 1 (the reference phase) to phase 2, and from phase 1 to phase 3. In addition, a Fast Fourier Transform (FFT) is performed on each phase voltage to provide Total Harmonic Distortion measurements. This paper describes the methods employed in the implementation of these functions on a single signal-conditioning card in order to provide detailed information about the power quality of a three-phase aircraft power source.
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In situ FTIR measurements of the kinetics of the aqueous CO2-monoethanolamine reactionMotang, Neo 03 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2015. / AFRIKAANSE OPSOMMING:
Raadpleeg die volteks vir opsomming, asseblief. / ENGLISH ABSTRACT:
Please refer to full text for abstract
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Adaptation of a Loral ADS 100 as a Remote Ocean Buoy Maintenance SystemSharp, Kirk, Thompson, Lorraine Masi 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The Naval Ocean Research and Development Activity (NORDA) has adapted the Loral Instrumentation Advanced Decommutation system (ADS 100) as a portable maintenance system for one of its remotely deployable buoy systems. This particular buoy system sends up to 128 channels of amplified sensor data to a centralized A/D for formatting and storage on a high density digital recorder. The resulting tapes contain serial PCM data in a format consistent with IRIG Standard 106-87. Predictable and correctable perturbations exist within the data due to the quadrature multiplexed telemetry system. The ADS 100 corrects for the perturbations of the telemetry system and provides the user with diagnostic tools to examine the stored data stream and determine the operational status of the buoy system prior to deployment.
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ADAPTATION OF A LORAL ADS 100 AS A REMOTE OCEAN BUOY MAINTENANCE SYSTEMSharp, Kirk, Thompson, Lorraine Masi 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The Naval Ocean Research and Development Activity (NORDA) has adapted the Loral Instrumentation Advanced Decommutation system (ADS 100) as a portable maintenance system for one of its remotely deployable buoy systems. This particular buoy system sends up to 128 channels of amplified sensor data to a centralized A/D for formatting and storage on a high density digital recorder. The resulting tapes contain serial PCM data in a format consistent with IRIG Standard 106-87. Predictable and correctable perturbations exist within the data due to the quadrature multiplexed telemetry system. The ADS 100 corrects for the perturbations of the telemetry system and provides the user with diagnostic tools to examine the stored data stream and determine the operational status of the buoy system prior to deployment.
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On the role of defect incompatibilities on mechanical properties of polycrystalline aggregates: a multi-scale studyUpadhyay, Manas Vijay 12 January 2015 (has links)
The main objective of this thesis is to obtain critical insight on the role of crystalline incompatibilities in strain and curvature, induced in presence of line defects i.e. dislocations and disclinations, on the energy and geometry of specific features of the local microstructure, and on the bulk mechanical response of nanocrystalline/ultra-fine grained
materials. To that end, studies are performed at the (1) inter-atomic and fine scale, and (2) at the mesoscale. The modelling approach is based on the field dislocation and disclination mechanics theory of continuously representated dislocations and disclinations. New, thermodynamically rigorous, multi-scale elastic constitutive laws based on the couple stress theory are developed to capture the effect of strain and curvature incompatibilities on the Cauchy and couple stresses. A new meso-scale elasto-viscoplastic constitutive model of defect incompatibilities based on a fast Fourier transform technique is developed. The desired scale transitioning is achieved via novel phenomenological defect density transport equations and the newly developed elastic constitutive laws.
At the fine scale, the model is applied to study energetic interactions between strain and curvature incompatibilities associated with grain boundaries and their influence on triple line energies. Results reveal that incompatible lattice strains have the most significant contribution to the energy. Incompatible lattice curvatures have negligible energetic contributions but are necessary to characterize the geometry of grain boundaries. Finally, both incompatible lattice strains and curvatures are necessary to capture the structure sensitive mechanical behavior of grain boundaries.
At the mesoscale, deformation of nanocrystalline aggregates characterized by residual curvatures is studied to identify the impact of the latter's presence on the local and bulk mechanical response of the aggregate. Relaxation of local stresses generated from residual curvatures reproduces the effect of GB dislocation emission. Uniaxial tensile loading of nanocrystalline microstructures containing residual curvatures reveals a softening in the yield stress which could explain the breakdown in Hall-Petch law in the nanocrystalline regime.
Next, the possibility of characterizing incompatibilities using X-ray or neutron diffraction techniques is tested. Results reveal that only strains and their gradients contribute to the broadening of diffraction peaks; curvatures and their gradients have no contribution. This study leads to the development of a new multi-scale averaged strain based Fourier technique for generating virtual diffraction peaks.
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DOPPLER SHIFTED SPREAD SPECTRUM CARRIER RECOVERY USING REAL-TIME DSP TECHNIQUESScaife, Bradley J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / In any satellite communication, the Doppler shift associated with the satellite’s position
and velocity must be calculated in order to determine the carrier frequency. If the satellite
state vector is unknown then some estimate must be formed of the Doppler-shifted carrier
frequency. One elementary technique is to examine the signal spectrum and base the
estimate on the dominant spectral component. If, however, the carrier is spread (as in
most satellite communications) this technique may fail unless the chip rate-to-data rate
ratio (processing gain) associated with the carrier is small. In this case, there may be
enough spectral energy to allow peak detection against a noise background.
In this paper, we present a method to estimate the frequency (without knowledge of the
Doppler shift) of a spread-spectrum carrier assuming a small processing gain and binary-phase
shift keying (BPSK) modulation. Our method relies on a simple, averaged discrete
Fourier transform along with peak detection. We provide simulation results indicating the
accuracy of this method. In addition, we will describe an all-digital hardware design
based around a Motorola DSP56303 and high-speed A/D which implements this
technique in real-time. The hardware design is to be used in NMSU’s implementation of
NASA’s demand assignment, multiple access (DAMA) service.
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An evaluation of the performance and mechanistic action of the costabiliser N-phenyl-3-acetyl pyrrolidine-2,4-dione and its derivatives in poly(vinyl chloride)Chaudhry, Humayun Iqbal January 1999 (has links)
No description available.
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Online fabric inspection by image processing technologyMalek, Abdel Salam 16 May 2012 (has links) (PDF)
The purpose of this thesis is to automate the online detection of weaving defects by a computerized system based on image processing software. Obviously, fabric inspection has an importance to prevent risk of delivering inferior quality product. Until recently, the visual defect detection is still under taken offline and manually by humans with many drawbacks such as tiredness, boredom, and, inattentiveness. Fortunately, the continuous development in computer technology introduces the online automated fabric inspection as an effective alternative. Because the defect-free fabric has a periodic regular structure, the occurrence of a defect in the fabric breaks the regular structure. Therefore, the fabric defects can be detected by monitoring fabric structure. In our work, Fast Fourier Transform and Cross-correlation techniques, i.e. linear operations, are first implemented to examine the structure regularity features of the fabric image in the frequency domain. To improve the efficiency of the technique and overcome the problem of detection errors, further thresholding operation is implemented using a level selection filter. Through this filter, the technique is able to detect only the actual or real defects and highlight their exact dimensions. A software package such as Matlab or Scilab is used for this procedure. It is implemented firstly on a simulated plain fabric to determine the most important parameters during the process of defect detection and then to optimize each of them even considering noise. To verify the success of the technique, it is implemented on real plain fabric samples with different colours containing various defects. Finally, a vision-based fabric inspection prototype that could be accomplished on-loom to inspect the fabric under construction with 100% coverage is proposed.
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Applications of grazing-angle reflection absorption Fourier transform infrared spectroscopy to the analysis of surface contaminationHamilton, Michelle LoAnn January 2007 (has links)
Cleaning validation of pharmaceutical manufacturing equipment is required by legislation. Generally, wet chemical techniques are employed using swabbing and/or rinse sampling methods. These are generally either selective and time consuming, or less selective and give results in a shorter period. The infrared reflection absorption spectroscopy (IRRAS) technique explored here attempts to deliver accurate, selective surface contamination information in real time to complement current methods and reduce down-time. The IRRAS instrument used in this research is a Fourier transform infrared (FTIR) spectrometer coupled by an IR fibre-optic cable to a grazing-angle sampling head with a fixed incidence angle of 80°. The introduced flexibility permits collection of in situ spectra from contaminated surfaces. Calibration models are developed using the multivariate, linear partial least squares (PLS) statistical method. The research focuses on sodium dodecyl sulfate (SDS), a model cleaning agent, on metal (aluminium and stainless steel) and dielectric (glass, EPDM and silicone) surfaces. The effects of surface finish are investigated for SDS on stainless steel. Calibrations for SDS and paracetamol in the presence of each other on glass surfaces are examined, as well as a common industrial cleaner (P3 cosa® PUR80) on polished stainless steel. For the calibration sets in this thesis, RMSECV values were < 0.41 µg cm⁻², corresponding to conservative surface residues detection limits of better than ~0.86 µg cm⁻². However, RMSECV values depend on the calibration loading range, and the detection limits were typically ~0.2 µg cm⁻² for loading ranges 0-2.5 µg cm⁻². These are below visual detection limits, generally taken to be 1-4 µg cm⁻², depending on the analyte and substrate. This shows that IRRAS is a viable method for the real-time detection and quantification of surface contamination by surfactants and active pharmaceutical ingredients on metals and dielectrics.
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