High frequency electronic ballast provides line frequency lamp current

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp current at the switching frequency. The high-frequency current flowing through the lamp can generate significant radiated noise, which is unacceptable in noise-sensitive applications, such as fluorescent lights in airplanes. Using shielded enclosures for the lamps may solve the problem, but it is expensive. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a magnetic ballast. However, compared to a magnetic ballast, its weight is substantially reduced due to operation at 40 kHz switching frequency. The topology also ensures unity power factor at the input and stable lamp operation at the output

Intruder between Rivers/Intruso entre rios

Ricardo Pau-Llosa and Enrico Mario Santf have recently published a bilingual volume of poetry, Intruder between Rivers/Intruso entre rios, with Pau-Llosa\u27s English originals and Santi\u27s translations of Cuban poems-poems with Cuban or Cuban exile themes. The reading wil be bilingual, in English and Spanish-or rather, Cuban-Spanish. This reading, as indeed the translation, is truly experimental-it casts Pau-Llosa\u27s elegant English prosody into the, hypothetical, original Cuban Spanish of both memory and daily experience.https://digitalcommons.fiu.edu/cri_events/1402/thumbnail.jp

Rapid Prototyping of Digital Controls for Power Electronics

The process for designing digital controls for power electronics is typically quite convoluted and affords many opportunities for errors to occur. We present here a new and complete, method for rapid prototyping of digital controls that allows rapid realization of new designs. The approach uses a collection of tools that include both software (the virtual test bed (VTB) and Matlab/Simulink) and hardware (dSpace DSP). An example application of the methodology completes the discussion

Notional System Models

The objective of this report is to set forth a group of time-domain models for the early-design stage study of shipboard power systems. These models are highly simplified abstractions of shipboard power system components. The motivation for the simplification is two-fold. First, at an early design stage it is doubtful if the parameters needed for a more detailed system representation would be available. A highly detailed simulation would be based on many assumptions leading to results which are no more indicative of actual performance than a highly simplified simulation. The second reason for the creation of highly simplified model is for the sake of computational speed, so that system simulations based on the component models will run at speeds compatible with the needs imposed by exploring the system behavior under a large variety of conditions.United States Office of Naval ResearchCenter for Electromechanic

Real-time feedback systems for cardiopulmonary resuscitation training: Time for a paradigm shift

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Notional System Report

The objective of this report is to set forth a group of time-domain models for the early-stage design study of shipboard power systems, and to demonstrate their use on various system architectures. The effort stemmed out of an earlier effort in which waveform-level models of three notional architectures – a Medium Voltage AC System, a High-Frequency AC System, and a Medium Voltage DC System were partially developed. Unfortunately, these codes were extremely computationally intense, limiting their usefulness for early design studies in which large numbers of runs, and a degree of user interactiveness, is required.Center for Electromechanic

A Rare Case of Carney-Stratakis Syndrome in a Patient With SDHA Mutation

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A new holistic 3D non-invasive analysis of cellular distribution and motility on fibroinalginate microcarriers using light sheet fluorescent microscopy

Cell interaction with biomaterials is one of the keystones to developing medical devices for tissue engineering applications. Biomaterials are the scaffolds that give three-dimensional support to the cells, and are vectors that deliver the cells to the injured tissue requiring repair. Features of biomaterials can influence the behaviour of the cells and consequently the efficacy of the tissue-engineered product. The adhesion, distribution and motility of the seeded cells onto the scaffold represent key aspects, and must be evaluated in vitro during the product development, especially when the efficacy of a specific tissue-engineered product depends on viable and functional cell loading. In this work, we propose a non-invasive and non-destructive imaging analysis for investigating motility, viability and distribution of Mesenchymal Stem Cells (MSCs) on silk fibroin-based alginate microcarriers, to test the adhesion capacity of the fibroin coating onto alginate which is known to be unsuitable for cell adhesion. However, in depth characterization of the biomaterial is beyond the scope of this paper. Scaffold-loaded MSCs were stained with Calcein-AM and Ethidium homodimer-1 to detect live and dead cells, respectively, and counterstained with Hoechst to label cell nuclei. Time-lapse Light Sheet Fluorescent Microscopy (LSFM) was then used to produce three dimensional images of the entire cells-loaded fibroin/alginate microcarriers. In order to quantitatively track the cell motility over time, we also developed an open source user friendly software tool called Fluorescent Cell Tracker in Three-Dimensions (F-Tracker3D). Combining LSFM with F-Tracker3D we were able for the first time to assess the distribution and motility of stem cells in a non-invasive, non-destructive, quantitative, and three-dimensional analysis of the entire surface of the cell-loaded scaffold. We therefore propose this imaging technique as an innovative holistic tool for monitoring cell-biomaterial interactions, and as a tool for the design, fabrication and functionalization of a scaffold as a medical device

Dynamical Characterization of Multi-Converter System : Simultaneous Measurement of Bus Impedance and Control Loop Gains

Interconnected power-electronics converters connected to a common bus have become increasingly important in various power-distribution systems. Due to interactions between converter subsystems the multi-converter system can often have stability issues even though each converter is standalone stable. Recent studies have presented a passivity-based stability criterion with which the stability of a multi-converter system can be analyzed by measuring the system bus impedance. The technique provides the stability of the complete system but does not reveal the dynamics of a single converter. The dynamics of single converters can be studied by other methods such as loop-gain measurements. The loop gains provide direct information on the operation of single converters and their stability margins but not the information about the global stability. This paper combines these techniques to simultaneously analyze the single converters and the complete multi-converter system. In the method, several orthogonal perturbations are injected into the converter control loops. The current and voltage responses are measured in the loop and from the converter outputs. After this, Fourier techniques are applied to obtain the spectral information of the loop gains and the bus impedance. The applied perturbations can be designed to have a very small amplitude, and thus, the process does not cause the system to deviate too much from its normal operation. Therefore, the method is well suited, for example, in online analysis and adaptive control. Experimental measurements are presented from a complex multi-converter system. The work is a revised and extended version of a presentation at ECCE2022.acceptedVersionPeer reviewe