Automated imaging, identification, and counting of similar cells from digital hologram reconstructions

This paper presents our method, which simultaneously combines automatic imaging, identification, and counting with the acquisition of morphological information for at least 1000 blood cells from several three-dimensional images of the same sample. We started with seeking parameters to differentiate between red blood cells that are similar but different with respect to their development stage, i.e., mature or immature. We highlight that these cells have different diffractive patterns with complementary central intensity distribution in a given plane along the propagation axis. We use the Fresnel approximation to simulate propagation through cells modeled as spheroid-shaped phase objects and to find the cell property that has the dominant influence on this behavior. Starting with images obtained in the reconstruction step of the digital holographic microscopy technique, we developed a code for automated simultaneous individual cell image separation, identification, and counting, even when the cells are partially overlapped on a slide, and accurate measuring of their morphological features. To find the centroids of each cell, we propose a method based on analytical functions applied at threshold intervals. Our procedure separates the mature from the immature red blood cells and from the white blood cells through a decision based on gradient and radius values.     

Speed Control of a Single-Frame Cascade Induction Motor with Slip-Power Pump Back

This paper describes an analytical and experimental study of a self-cascade single-frame brushless induction motor, using a rectifier- inverter to control speed by slip-power pump back to the line. Steady- state analyses of asynchronous and synchronous performance and test results of a special machine wound for the study are presented. The effect of machine parameters, windings, and construction is discussed. The performance and rating of the brushless cascade machine are found to be equivalent to the slip-ring induction motor or wound-field synchronous machine built into the same frame.     

Tunable Fabry-Perot surface micromachined interferometer-experiments and modeling

We present an optical tunable Fabry-Perot micromachined interferometer. The device is monolithically integrated with a p⁺-n photodiode on a silicon substrate, providing an adequate positioning of the photonic and microoptical components. The Fabry-Perot micro-interferometer consists of two parallel mirrors and lets the light with a particular wavelength pass through. The wavelength depends on the gap between the mirrors. We can change the gap of the micro-mechanical Fabry-Perot interferometer by applying a voltage to the mirrors, an electrostatic force inducing an attraction between the substrate and the top mirror. A simulation of the mechanical behavior was performed based on finite elements, using CoventorWare software. The method included an electro-mechanical simulation for a square parallel plate actuation with four connecting beams. The finite elements method (FEM) simulations of the device (the Fabry-Perot tunable filter) are performed for optimizing the design parameters in order to model the overall system performance, both the steady-state behavior and dynamic response.     

Stored energy - Short-term and long-term energy storage methods

This paper deals with the short-term and long-term energy storage methods for standby electric power systems. Stored energy is required in uninterruptible standby systems during the transition from utility power to engine-generator power. Various storage methods provide energy when the utility source fails. For batteries in cycling duty, Li-ion and Ni-MH cells are coming into wide use to displace VRLA batteries. For float duty, VRLA and NiCd batteries predominate. Flywheel-generator units are being offered to replace batteries in UPS. Fuel cells require a warm-up time and, hence, are suitable for long-term operation. Ultracapacitors are proposed to replace batteries for short-term discharge. CAED and hydrogen energy storage are suitable for large projects.     

Transfilter

The Transfilter is a combination of a leakage-reactance magnetic structure and a capacitor, which is interposed between an ac thyristor voltage controller and the load, to filter the load current, to provide current-source characteristics, and to act as an isolation and impedance-level transformer. The Transfilter was originally developed to provide sinewave adjustable current up to 50 A at 60 Hz for an automatic power-system-relay tester.     

Nondestructive Analysis of Total Nonvolatile Carbon by Forward Alpha Scattering Technique (FAST)

The oldest method of nuclear analysis, Rutherford scattering of alpha particles, is the basis of a technique we have developed that is capable of the quantitative nondestructive determination of carbon and all other elements lighter than sodium on an aerosol filter. Samples are collected on thin-stretched teflon filters, which are then placed in the 30-MeV alpha-particle beam of the Crocker Nuclear Laboratory's 193-cm cyclotron. Scattered alpha-particles are detected at the forward angles of 62 and 74 degrees, and the method has become known as FAST, for forward alpha scattering technique. The fluorine content of the air particles is assumed to be much less than the carbon content, and the filter blank carbon is subtracted from the known CF₂ ratio of teflon. Sensitivities for carbon are limited by the need to subtract the 70 μg/cm² of carbon in the filter, which can be done to ±5%, or ±3.5 μg/cm². This amounts to ±0.15 μg/m³ for the National Park Service aerosol samples. Since the FAST analysis is done in vacuum, only nonvolatile species are measured. This technique provides an alternative way to measure carbon without using artifact-prone quartz filters.     

Computer-aided design and analysis of power-harmonic filters

Power harmonic filters for rectifiers, motor drives and uninterruptible power systems are usually designed by characterizing currents and voltages by their harmonic components. Usually, no attempt is made to determine the effect of switching of the filters, or of the system operation during a fault in the filter. A superior design method is to use modeling tools to characterize the currents and voltages by their instantaneous values as a function of time. Computer modeling using PSpice is a suitable alternative. In the computer modeling approach, the filter load, for example, a six-pulse phase-controlled converter can be represented accurately. Switching of the power harmonic filters can be accurately represented to determine the turn-on transients. The effect of unbalanced system operation with one filter phase open can be determined. A computer model of an elevator drive system using a full-compliment six-pulse phase-controlled converter with fifth and seventh harmonic tuned filters, connected to an enhanced DC machine model is presented. Resulting waveforms show that the computer model can accurately simulate the static and dynamic characteristics of the entire elevator drive system for four test conditions in just one simulation run     

Testing the 500-MHz IBM S/390 microprocessor

The design-for-test framework of the 500-MHz CMOS central processor uses specific tests to ensure the highest reliability of components within a system. Some of the same test patterns are applied in chip manufacturing and system-level tests