Using Virtual Instrument in Teaching Automatic Measurement Technology Course

The use of an automatic measurement technology is highly important in current industries. The technology has been sued in various applications such as environment monitoring, quality control of production line, and medical disease analysis. Automatic measurement technology requires programming, facilities integration, control application, function innovation, and maintenance technology. Developing suitable teaching equipment that can satisfy the demand of industry-orientation Automatic Measurement Technology Course (AMTC) is a challenge. In this study, a virtual instrument is introduced to solve the problem. LabVIEW, which is utilized to design virtual instruments, provides powerful functions for instrument control and measurement. Therefore, in this proposed AMTC, anbsp LabVIEW-based virtual instrument system is established as teaching equipment for undergraduate students in colleges of engineering or technology

TWO-PHOTON PHOTOEMISSION SPECTROSCOPY OF WET ELECTRON STATE AND FEMTOSECOND ELECTRON DYNAMICS ON TiO2 SURFACES

Combination of the femtosecond laser time-resolved two-photon photoemission (TR-2PP) and the ultra high vacuum (UHV) surface science preparation techniques provides the possibility to study the electronic structures and the interfacial electron transfer dynamics at the atomically ordered adsorbate overlayers on single-crystalline surfaces, such as TiO2. The nearly perfect, stoichiometric TiO2 surface is prepared by a standard surface-preparation protocol, while various UHV surface preparation methods are available to modify the stoichiometric surfaces by introducing defects and/or adsorbed molecules. Two-photon photoemission (2PP) spectroscopy with near ultraviolet (400 nm) femtosecond laser pulses are used to investigate systematically the work function, and the occupied and unoccupied electronic structure of TiO2 surfaces due to the presence of defects and adsorbates. Adsorbates e.g. O2, H2O, CH3OH are introduced onto TiO2 surfaces to investigate their interaction with the TiO2 surface, as well as the ultrafast interfacial charge transfer dynamics. O2 molecules act as electron acceptors and titrate (heal) the surface O atom vacancy defects. H2O acts as an electron donor and forms a monolayer structure with an effective electric-dipole of 0.5 D pointing outwards. More remarkably, at ~1 monolayer coverage of water with minority -OH species present on TiO2 surfaces, an unoccupied state of 2.45 eV above the Fermi level is observed. Density functional theory shows this to be a ¡°wet-electron¡± state, representing the lowest energy nonadiabatic electron transfer pathway through the interface. The decay of the wet-electron state through the reverse charge transfer occurs within 15 femtoseconds, faster than the dielectric response time scale of the H2O overlayer. Similarly, the chemisorption of CH3OH molecules on TiO2 surfaces induces a related resonance at 2.3 0.2 eV above the Fermi level. Following the injection of electrons into the CH3OH overlayer we can follow by pump-probe measurements the ultrafast dielectric response of the interface leading to the solvation of injected electrons. Surprisingly, the solvation dynamics exhibit a strong deuterium-isotope effect. The excess charge is stabilized by the structural reorganization of the interface involving the inertial motion of substrate ions (polaron formation), followed by slower diffusive solvation by the molecular overlayer. According to the pronounced isotope effect on the electron lifetime, this motion of heavy atoms transform the reverse charge transfer from a purely electronic process (nonadiabatic) to a proton-coupled electron transfer (PCET) regime on ~30 fs time scale

An Alternate Control Scheme for Reconfigurable Virtual Instruments

The widespread usage of personal computers in many scientific and technological fields makes them an ideal hardware and software platform for the implementation of measurement instruments. Reconfigurable virtual instruments are implemented using a universal general purpose reconfigurable hardware whose functionality is defined by the measurement requirement. It is a versatile hardware device that can be reconfigured into different electronic instruments using a software tool. A high-level software application runs on the PC and provides a user interface to the operator who can select a virtual instrument (e.g. digital oscilloscope, arbitrary waveform generator, logic analyzer, digital filter?) from a library of instruments and configures the RVI system to convert it into the selected instrument with its associated console. The speech recognition interface enhances the ability of the operator to control various system components without manually navigating the graphical user interface (GUI). Several options were considered during the analysis but only one option proved to be optimal. The solution described in this paper uses the NXP semiconductors ARMLPC2148 microcontroller to handle all speech recognition calculations. The GUI control system runs on the main PC processor and the controlled instruments are attached to the system through RS232 interface. Speech recognition performance analysis is done for both PC based approach and dedicated hardware based approach in terms of realizing and controlling the VIs and the results are compared

Experiential Learning in Computer Engineering using Medium Complexity Logic Design Circuits

Abstract- One of the main tracks of research is about Low-cost computing devices in engineering educations. This track face the problem that conventual methods are either too trivial demonstrative educational examples, or too abstracted that it hides away the necessary details students should learn, or too complex industry grade demonstrations. This research targets to utilize lost cost computing devices, and produce medium complexity educational component using analog to digital, digital to analogy circuits integrated with Field Programmable Gate Array (FPGA) devices. A medium level complexity example is illustrated in this paper using Analog to Digital and Digital to Analog converter board attached to FPGA development board. A comparison between conventional methods and proposed methods is also presented showing advantages of FPGA based logic design implementations.A medium level complexity example is illustrated in this paper using Analog to Digital and Digital to Analog converter board attached to FPGA development board. A comparison between conventional methods and proposed methods is also presented showing advantages of FPGA based logic design implementations

Analysis of vibration and acoustic signals for noncontact measurement of engine rotation speed

The non-contact measurement of engine speed can be realized by analyzing engine vibration frequency. However, the vibration signal is distorted by harmonics and noise in the measurement. This paper presents a novel method for the measurement of engine rotation speed by using the cross-correlation of vibration and acoustic signals. This method can enhance the same frequency components in engine vibration and acoustic signal. After cross-correlation processing, the energy centrobaric correction method is applied to estimate the accurate frequency of the engine's vibration. This method can be implemented with a low-cost embedded system estimating the cross-correlation. Test results showed that this method outperformed the traditional vibration-based measurement method.Web of Science203art. no. 68

Continuous harmonic analysis and power quality measurements in three-phase systems

A virtual instrument, named Power Quality Meter, is presented for (a) measuring power consumption and harmonics in three-phase systems, under non-sinusoidal and imbalance conditions (b) detecting, classifying and organizes power disturbance events. Measurement of the power consumption follows the formulation proposed by the members of the IEEE Working Group on Nonsinusoidal Situations (1996). So, definitions are based on the analysis of functions in the frequency domain, separating the fundamental terms from the harmonic terms of the Fourier series. The virtual instrument has been developed too for monitoring and measuring power disturbances, which are automatically classified and organized in a database while they are being recorded. Software tools use the database structure to present summaries of power disturbances and locate an event by severity or time of occurrence. Records of actual measurements are included to demonstrate the versatility of the instrument