Microcomputer-based Data Acquisition System Research Articles

Simulating birth to investigate clinician-applied loads on newborns

This report describes the design, development and testing of a force-measuring birth simulator. Designed to mimic the feel of an obstetric emergency, the simulator is named shoulder dystocia birth model (SDBM). The SDBM consists of a simply supported overhung beam, instrumented with two strain gauges and one commercially-available sensor, all of which are embedded in a maternal manikin that rests on a height-adjustable scissors jack. Rigidly affixed to the free end of the beam, a model of a newborn head protrudes from the manikin to allow physicians to simulate the loads they exert when delivering a newborn. A microcomputer-based data acquisition system monitors, analyses and processes the output from the gauges and the sensor in real time. The system measures axial force and vertical force to within 2% accuracy and the end-moment to within 5% accuracy. Testing with 15 University of Maryland clinicians simulating routine, difficult and SD deliveries reveals average peak force magnitudes of 68 N, 118 N and 172 N and average peak moment magnitudes of 138 N.cm, 384 N.cm and 621 N.cm, respectively. The standard deviations for these average peak values are large indicating wide variation in perceived loads required to deliver. Confirming clinical observation, average peak forces for some difficult and many shoulder dystocia deliveries exceed the force necessary to induce clavicle fracture at birth.

A microcomputer-based data acquisition system for transient network analyzer operation

The transient network analyzer (TNA) is a collection of miniature models used to simulate the effects of switching events on power systems and to study various electromagnetic transient phenomena. This paper describes how a new microcomputer is used to serve as a high-performance data acquisition system for TNA operations. The system provides high-speed, synchronous acquisition of multi-phase voltage and current waveforms as well as control of circuit breaker closing-angles for statistical analysis. The computer interfaces with the TNA by means of plug-in boards containing analog-to-digital and digital-to-analog converters. The user interface is implemented with a graphical programming environment to provide controls and indicators on a front panel similar to those found on an oscilloscope. The new technology applied to the system make it a compact, highly flexible, and powerful tool.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Modeling Soil Water Redistribution and Extraction Patterns of Drip-Irrigated Tomatoes Above a Shallow Water Table

A mathematical model was developed to simulate soil water infiltration, redistribution, and extraction in a bedded soil profile overlaying a shallow water table and irrigated by a line source drip irrigation system. The model uses an implicit finite difference scheme with explicit linearization of soil parameters. Its accuracy was verified by comparison of simulated results to numerical and steady-state analytical solutions from the literature. The model was then used to simulate two-dimensional soil water movement as observed in a lysimeter study. A bedded and plastic-mulched soil profile that was irrigated by a line source drip system and influenced by a shallow water table was studied in the lysimeters. The model results were in good agreement with the lysimeter data collected using a tensiometer-pressure transducer microcomputer based data acquisition system.

A PC-based tissue classification system using artificial neural networks

The author presents a pattern recognition algorithm and describes required instrumentation for ultrasound classification of simulated human-liver tissue abnormalities. The tissue is simulated by a liver phantom that mimics the tissue acoustically. The instrumentation used, a 50-MHz microcomputer-based data acquisition and analysis system designed by the author, digitizes the ultrasound backscattered signal from selected regions of the phantom and processes the digitized data for feature measurement. The algorithm is based on a three-layer backpropagation artificial neural network; trained to differentiate between simulated normal and abnormal tissue and to classify three types of simulated abnormalities. The results show that out of 28 cases the system classifies 25 correctly and fails to classify three cases. The reasons for this are discussed along with recommendations to increase the accuracy of classification. >

A simple, microcomputer based data acquisition system for monitoring pH shifts

A simple, microcomputer based data acquisition system for monitoring pH shifts

A simple, microcomputer based data acquisition system for monitoring pH shifts

The use of ‘of the shelf’ microcomputer hardware and software and a new type of laboratory style combination pH electrode with a built in preamplifier makes it possible to monitor pH shifts in a group of experimental vessels in a time frame of seconds without resorting to expensive smart switch boxes or multiple pH meters. A data acquisition system is described for monitoring pH shifts.

Measuring whole-body vibration of forest equipment operators with a digital data acquisition system

A microcomputer-based data acquisition system (MDAS) was developed to collect whole-body vibration data in a study of forest machine operators. This system was implemented with a combination of standard off-the-shelf hardware and custom-built circuits. The installation of suitable signalconditioning cards in the unit permits the system to be used for the measurement of all standard physical quantities. The design provided for recording the data in digital form on a 10-Mbyte removable cartridge data-storage subsystem. Hardware and software development and the operation of the MDAS is discussed.

Microcomputer-based data acquisition systems for triaxial testing of soft yielding rocks

Microcomputer-based data acquisition systems for triaxial testing of soft yielding rocks

A microcomputer-based data acquisition system for an NMR pulse spectrometer

A data acquisition card is designed and constructed for the Amstrad PC 1512, a low-cost IBM compatible microcomputer. This card is installed in the expansion slot of the microcomputer and the software necessary for nuclear magnetic resonance data acquisition and analysis is developed. This system generates the pulse sequences necessary for a nuclear magnetic resonance pulse spectrometer and acquires data from the free-induction-decay signal for further analysis. The generation of the timing pulses and the capturing of the free-induction-decay signal are done with the help of an assembly language source program.

Frequent handling in the neonatal intensive care unit and intraventricular hemorrhage

The association between periventricular-intraventricular hemorrhage (PV-IVH) and frequent handling resulting from various neonatal intensive care procedures and routine interventions was evaluated in a prospective clinical study. Inborn premature babies with birth weight less than or equal to 1500 gm (n = 156) who did not have PV-IVH or who had grade 1 PV-IVH at less than or equal to 1 hour were randomly assigned to the reduced manipulation protocol (n = 62) or to standard care (n = 94). A bedside microcomputer-based data acquisition system was used to monitor the duration of rest or the number of interventions per day. Infants assigned to receive reduced manipulation spent a significantly higher percentage of time each day at rest than did those who received standard manipulation (p less than 0.006). However, the incidence of grades 2 to 4 PV-IVH did not differ significantly (30% in the study vs 37% in the standard manipulation group). When we analyzed the effect of manipulation in relation to risk of PV-IVH, while taking into account other perinatal variables, standard manipulation was not associated with increased risk of grades 2 to 4 PV-IVH. However, low birth weight, maternal smoking, general anesthesia, early grade 1 PV-IVH, low hematocrit, lowest arterial oxygen pressure within the first 6 hours of life, and large base deficit at 6 hours of age all increased the relative risk of grades 2 to 4 PV-IVH.

A microcomputer-based multiparameter nuclear data acquisition system

Abstract An inexpensive and flexible microcomputer-based CAMAC data acquisition system is described. Quantitative performance characteristics are given to allow calculation of acquisition speed for an arbitrary configuration.

Microcomputer-based data acquisition system for clinical research

We have described a computerized data acquisition system for clinical investigation that can record over fifty physiologic variables from up to twenty-four electronic monitors. The information is acquired by a personal computer using RS-232C serial communications and analog-to-digital conversion. In its present configuration the system records information from a Spacelabs 500 series physiologic monitor, Hewlett-Packard physiologic monitor with the Careport computer interface, SARA mass spectrometer, Nellcor pulse oximeter, Neurotrac processed EEG, Lawrence cardiac output monitor, Hewlett-Packard capnometer, and Bourns spirometer. The software can be easily modified to accommodate other physiologic monitors. The system records parameter or waveform information and writes the data into a file that can be accessed by commercially available graphical and statistical packages. The data acquisition system is easy to use, transportable, and inexpensive.

Low cost data acquisition system for transport characterization of high-T c superconductors

A low cost microcomputer-based data-acquisition system designed specifically to perform transport characterization of high-Tc superconductors is presented. It can measure the temperature dependence of both the resistance and the critical current. It utilizes the four-point ac in-phase method to eliminate the effects of lead and contact resistance and thermal voltages. Some of the advantages of this method over dc methods are pointed out. The system is implemented on a PC (IBM or compatible) through the IEEE-488 interface. The temperature is controlled by the system with resolution and accuracy of 0.1 and ±0.5 K, respectively, which are the limits of the platinum thermometer used. Voltages in the sample can be measured with a resolution better than 5 nV. The system can be easily modified to measure the critical current dependence on an applied magnetic field.

Continuous Soil Water Potential Measurement With a Microcomputer-Based Data Acquisition System

A microcomputer-based data acquisition system for continuous soil water potential measurements was developed from commercially available components. The system consisted of tensiometer-mounted pressure transducers, a work station data acquisition and control device, and a portable microcomputer. The system was installed and tested in a set of lysimeters that simulated typical vegetable growing conditions in Florida. The system was self-booting and could operate unattended for weekly periods. It was in continuous operation for a three-month growing season during which it proved extremely effective in monitoring temporal variation of soil water potential. This microcomputer-based data acquisition system can potentially be used to automatically operate an irrigation system in response to sensor readings at remote sites in the field.

Algorithm and instrumentation for isolated-word recognition

In this study we present algorithm and instrumentation for isolated-word recognition. The algorithm is based on calculating the Linear Predictive Coefficients (LPC) of order 10 of the spoken word. Two pattern recognition techniques have been implemented to recognize the spoken word: dynamic time warping, where the distance between the training and the reference sets is taken as a measure of matching, and a three-layer back-propagation artificial neural network. A vocabulary of 30 tape-recorded short-duration words is selected. The first technique shows an accuracy of 85%; the second shows an accuracy of 99%. To implement and test the proposed algorithms a microcomputer-based data acquisition system has been designed and constructed.

A microcomputer based data acquisition system for the KGF nucleon decay experiment

We have adapted a microcomputer based data acquisition system using the concept of parallel processing. The active detector components consisting of 3800 proportional counters, are read out by a network of nine Z-80 based microprocessor modules. A look-up table concept for generating various trigger schemes has also been implemented.

Measuring dynamic response of soil subjected to impact loading

A microcomputer-based data-acquisition system was developed and employed for high-frequency monitoring of soil dynamic response to impact loading. The measurement system monitored a probe impacted into the in situ surface of clay loam, fine sandy loam and silt loam soils. Data defining impact force on the prove vs. depth of penetration were obtained for probe diameters ranging from 9.5 to 19.1 mm and probe impact velocities ranging from 2.0 to 5.0 m s −1. Data analysis for 216 tests indicated that soil-penetration depth strongly affected peak probe force. A regression model based upon input energy, probe diameter and soil-penetration depth was developed to predict peak impact force on a probe.

Pressure fluctuations measurement and analysis in hydraulic jumps using a microcomputer

Abstract This paper presents a microcomputer based data acquisition system and an analysis of pressure fluctuations in the range of weak hydraulic jumps. Statistical analysis of data shows that the distribution of pressure fluctuations follows the Gaussian probability density function. The maximum pressure fluctuation amplitude is found to be in the range of 2.5 to 3.5 times the standard deviation. The spectral analysis of data indicates that large eddies in the low frequency range of 0 to 20 Hz are predominant over the small eddies in the high frequencies. This result is also predicted by the empirical correlation coefficient. Based on cross correlation analysis, the relationship between areal pressure fluctuations and point pressure fluctuations is developed and can be used to prevent over‐designing the strength of the stilling basins. It shows that the areal pressure fluctuations decrease as the jump longitudinal dimension increases.

Effects of geometry on the intensity of transmitted longitudinal waves

This paper presents a method for determining the effects of geometry on the intensity distributions of ultrasonic longitudinal plane wave fronts (plane waves is assumed) transmitted through a specimen with geometric deformation. Its feasibility is demonstrated with the aid of a microcomputer-based scanning and data-acquisition system.

A Micrometeorological Facility for Eddy Flux Measurements of CO2and H2O

A ground-based eddy flux system which is used to measure the CO2 and H2O exchange between the atmosphere and the biosphere is described. Fluctuations of CO2, H2O, air temperature and atmospheric turbulence are sampled at frequencies up to 50 Hz. A microcomputer-based data acquisition system is used to calculate in real time, using standard hardware, the raw and corrected flux of CO2, latent and sensible heat and momentum. Flux density data taking into account all known sources of energy exchange in a maize crop are presented as an example of the strategy employed to control the quality of the data in measuring eddy fluxes under field conditions and to demonstrate the sources of errors and the degree of accuracy which we can obtain CO2 and H2O flux density measurements with modern equipment.