Computer-controlled Instrumentation Research Articles

A Study of the Connection Between Bending Stress and Belt Friction Using a Servomotor Controlled by a Computer

The aim of the publication is to design an analytical relationship for determining the bending coefficient measurable by belt friction. Following the results of the presented measurements, the theoretical assumption is verified that in the material of the belt stress arises during the friction of the contact surfaces, due to external forces and bending of the belt. Selected experiments of drawing a polypropylene belt at a constant speed over an aluminium cylindrical surface are carried out using a servo drive on a measuring bench with computer-controlled instrumentation. The results of friction and bending coefficient measurements are interpreted in connection with the setting of various input parameters (especially friction surfaces and belt thicknesses), at a constant shaft speed. The newly identified dimensionless bending coefficient of belt friction is a material coefficient with a comparative information value concerning the flexibility of the belt, suitably supplementing the friction Euler-Eytelwein coefficient. The presented publication can be suitably applied especially to the engineering educational process.

A posteriori correction of camera characteristics from large image data sets.

Large datasets are emerging in many fields of image processing including: electron microscopy, light microscopy, medical X-ray imaging, astronomy, etc. Novel computer-controlled instrumentation facilitates the collection of very large datasets containing thousands of individual digital images. In single-particle cryogenic electron microscopy (“cryo-EM”), for example, large datasets are required for achieving quasi-atomic resolution structures of biological complexes. Based on the collected data alone, large datasets allow us to precisely determine the statistical properties of the imaging sensor on a pixel-by-pixel basis, independent of any “a priori” normalization routinely applied to the raw image data during collection (“flat field correction”). Our straightforward “a posteriori” correction yields clean linear images as can be verified by Fourier Ring Correlation (FRC), illustrating the statistical independence of the corrected images over all spatial frequencies. The image sensor characteristics can also be measured continuously and used for correcting upcoming images.

Virtual instrumentation in LabVIEW for multiple optical characterizations on the same opto-mechanical system

In this work we propose a virtual instrumentation, user-friendly, computer-controlled instrumentation and data analysis techniques, allowing an instantaneous comparison between theoretical predictions, simulations and actual experimental results. These applications in LabVIEW programming software show a virtual explosion in data acquisition and control system from the laboratory. We consider a versatile opto-mechanical system θ–2θ by using the p-polarized light from a He–Ne laser in which the surface plasmon resonance, Brewster and Brewster-Abelès methods, and scattering measurements are driven by LabVIEW software that produces fast, simple and accurate measurements of samples. The application can be used for both education and specific research purposes.

New approach to remote laboratory in regard to topology change and self-repair feature

Abstract Remote laboratories deal with performing real lab experiments remotely via the Internet. Recent advances in the Internet/web technologies and computer-controlled instrumentation allow net-based techniques to be used for setting up remote real laboratory access. This paper deals with the solutions for remote laboratory providing services for the operation of remote laboratory. The paper addresses problems related to the requirement of flexible, secure and easy remote access to laboratory equipment as well as the need for hardware and/or software re-configuration. This paper presents a unique concept for logical topology change with the usage of Q-in-Q tunneling and automated self-repair feature after failure.

Optical imaging of the cervix.

Recent advances in fiber optics, sources and detectors, imaging, and computer-controlled instrumentation have stimulated a period of unprecedented growth in the development of photonics technologies for a wide variety of diagnostic and therapeutic clinical applications. These include the application of quantitative optical spectroscopy and imaging for the detection of precancerous lesions in the uterine cervix, a topic of interest at the Second International Conference on Cervical Cancer, which was held April 11-14, 2002. Investigators have applied the Littenberg method of emerging technology assessment to new optical methods used to detect cervical neoplasia. Currently, such technologies as fluorescence spectroscopy (the combination of fluorescence and diffuse reflectance spectroscopy), tri-modal spectroscopy, and light-scattering spectroscopy that probe the spectral characteristics of tissue are being investigated. Optical technologies that create images of subcellular structure without biopsy subsequent to pathology that currently are under investigation include in vivo confocal imaging and optical coherence tomography. Numerous small studies have demonstrated the potential of these optical technologies. What remains to be elucidated are the fundamental biophysical origins of variations in remitted optical signals between normal and dysplastic tissue. Large multicenter randomized controlled trials are needed to confirm the detection and imaging capabilities of optical technology. Furthermore, the development of contrast agents that could boost detection with these technologies is needed, and basic biologic characterization of signals should be pursued. Applying the Littenberg assessment will help ensure that superior, not simply alternative, technologies are implemented.

Computer-controlled instrumentation for fast voltammetry at ultramicroelectrodes

In this article we describe an electrochemical experimental setup for cyclic voltammetry operating from low (1 V/s) to very high (200 kV/s) scan rates. The system is designed to achieve an acceptable cost and to be user friendly for nonexperts. The instrumentation is based on a commercial arbitrary wave form generator, a digital oscilloscope, a general purpose interface bus interface to a PC, and a laboratory-built potentiostat. There are no complicated manual operations, instead the software creates dialog with an operator to control commands for the instruments. Requirements for the wave form synthesis and the data acquisition are given. Various data-smoothing methods for treating 8-bit fast scan data are evaluated. The performance was tested on the oxidation of ferrocene in acetonitrile. The estimated value of the standard heterogeneous rate constant, k0=0.8±0.1 cm s−1, is in reasonable agreement with the most recent reports from other laboratories.

A microfluidic system for high-speed reproducible DNA sizing and quantitation.

Microfabrication technology was used to develop a system consisting of disposable glass chips containing etched channels, reagents including polymer matrix and size standards, computer-controlled instrumentation for performing electrophoretic separations and fluorescence detection of double-stranded DNA, and software for automated data analysis. System performance was validated for separation and quantitation reproducibility using samples varying in amount and size of DNA fragments, buffer composition, and salt concentrations. Several applications of the microfluidic system for DNA analysis have been demonstrated, such as of polymerase chain reaction (PCR) products, sizing of plasmid digests, and detection of point mutations by restriction fragment length polymorphism (RFLP) mapping.

Train-generated sound within an underground light railway system

An empirical study has been made to identify important features of sound levels generated within an underground section of a light railway. Measurements of sound pressure level were recorded as trains passed within a few metres of computer-controlled instrumentation during normal daytime operation. Peak values of sound pressure level were identified for each passing train and a method of compensating for train speed was investigated. Further measurements were taken of sound levels as two Metro trains were repeatedly driven through the same section of underground track at different nominal speeds during a night-time possession. Characteristics of sound levels produced by approaching and departing trains have been studied to identify any salient features that may be beneficial in developing a means of monitoring the condition of passing trains. No definitive relationship was identified between train speed and peak value of sound pressure level, although results indicated that higher sound exposure levels and duration when a passing train generates sound levels above a threshold value can be linked to train condition. Further development of the work is planned to provide an automated management tool for identifying trains in need of further inspection and maintenance. The ultimate aim is to improve the efficiency of scheduling for train maintenance and to satisfy environmental needs for keeping train-generated sound to minimum levels.

Computer-Controlled Instrumentation for Accurate Mass Determination by Peak Matching in Mass Spectrometry

Peak matching, although a tedious and somewhat subjective process, has long been used with sector mass spectrometers for accurate mass determination. Computer-assisted control and data acquisition can remove the subjectivity and make the process faster and less tedious. The circuits for data acquisition and sweep generation and the data analysis programs that provide these advantages are described. These can also be used, with minor modification, for peak ratio determinations.

Where to Buy Computer-Controlled Instrumentation for PC and Mac

Where to Buy Computer-Controlled Instrumentation for PC and Mac

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Authors

The application of the methods of electrode kinetics, especially the impedance, to the study of gas evolving reactions at electrodes

The methods of electrode kinetics, particularly steady state current-potential and impedance-potential measurements, have been successfully applied to the investigation of gas forming reactions, such as chlorine, oxygen and hydrogen evolution. Developments in computer-controlled instrumentation have made these the preferred methods (together with potential pulse methods). The paper discusses the results and suggests how these can be interpreted in terms of the electron transfer reaction and the bubble layer.

Development of a totally computer-controlled triple quadrupole mass spectrometer system

A totally computer-controlled triple quadrupole mass spectrometer (TQMS) is described. It has a number of unique features not available on current commercial instruments, including: complete computer control of source and all ion axial potentials; use of dual computers for data acquisition and data processing; and capability for self-adaptive control of experiments. Furthermore, it has been possible to produce this instrument at a cost significantly below that of commercial instruments. This triple quadrupole mass spectrometer has been constructed using components commercially available from several different manufacturers. The source is a standard Hewlett-Packard 5985B GC/MS source. The two quadrupole analyzers and the quadrupole CAD region contain Balzers QMA 150 rods with Balzers QMG 511 rf controllers for the analyzers and a Balzers QHS-511 controller for the CAD region. The pulsed-positive-ion-negative-ion-chemical ionization (PPINICI) detector is made by Finnigan Corporation. The mechanical and electronics design were developed at LLNL for linking these diverse elements into a functional TQMS as described. The computer design for total control of the system is unique in that two separate LSI-11/23 minicomputers and assorted I/O peripherals and interfaces from several manufacturers are used. The evolution of this design concept from totally computer-controlled instrumentation into future self-adaptive or ‘‘expert’’ systems for instrumental analysis is described. Operational characteristics of the instrument and initial results from experiments involving the analysis of the high explosive HMX (1,3,5,7-Tetranitro-1,3,5,7-Tetrazacyclooctane) are presented.

Computer-assisted indirect coulometric titrations of biological redox components

The optically coupled, indirect coulometric titration (ICT) method has been applied to assist in the characterization of several redox biocomponents such as heme proteins. This method has provided rapid and repetitive evaluation of redox stoichiometry and energeties with a high degree of precision. The usual manual ICT procedure requires operator control of the repetitive incremental additions of electrochemical charge, the on/off of the magnetic stirrer between such additions, and the recording of optical spectra after each addition. The sequence and timing of events in the above procedure can be fixed which then lends itself ideally to computer control. In this paper, a computer-controlled ICT intsrumentation is described. The hardware and software developed for the computerization permit versatility of displaying ICT data in various formats, i.e., conventional absorbance or derivative spectra and dual wavelength or differences between dual-wavelength spectra. Also, absorbance at a given wavelength could be obtained from the spectra as a function of the incremental addition of charge. The three-dimensional plots of spectral absorbance as a function of wavelength and incremental charge could also easily be obtained. To demonstrate the capability and versatility of the computer-controlled instrumentation, the ICT of the redox components, cytochrome c and cytochrome c oxidase, and of intact mitochondria is presented.

Computer-Controlled Teaching Instrumentation for Linguistic Studies with the Great Apes

A minicomputer has been interfaced with keyboards, visual display projectors, and vending devices, forming a 24 hour/day teaching instrumentation system for linguistic studies with a chimpanzee. Employing visual, geometric word-symbols with a 12-element construction (9 elements and 3 colors) a 4 year old female chimpanzee over a 2 year period has learned 70-80 words which she uses productively in numerous sentences to gain most of her sustenance, entertainment, and companionship (human). The computer evaluates her inputs for proper syntax and mediates in conversations between her and the experimenters. All interchanges are recorded.

Experimental study of 1/f noise stationarity by digital techniques

Electronic noise measurements in carbon resistors, germanium, cadmium sulfide, and thermionic devices over the frequency range 2 Hz to 2 kHz are presented, using a real-time computer-controlled instrumentation system. The reproducibility and resolution of this system were sufficient to identify small but significant statistical differences between 1/f- and Nyquist-type noise sources which have not been observed in previous investigations.