There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This International Myeloma Working Group consensus updates the disease defi nition of multiple myeloma to include validated biomarkers in addition to existing requirements of attributable CRAB features (hypercalcaemia, renal failure, anaemia, and bone lesions). These changes are based on the identifi cation of biomarkers associated with near inevitable development of CRAB features in patients who would otherwise be regarded as having smouldering multiple myeloma. A delay in application of the label of multiple myeloma and postponement of therapy could be detrimental to these patients. In addition to this change, we clarify and update the underlying laboratory and radiographic variables that fulfi l the criteria for the presence of myeloma-defi ning CRAB features, and the histological and monoclonal protein requirements for the disease diagnosis. Finally, we provide specifi c metrics that new biomarkers should meet for inclusion in the disease defi nition. The International Myeloma Working Group recommends the implementation of these criteria in routine practice and in future clinical trials, and recommends that future studies analyse any diff erences in outcome that might occur as a result of the new disease defi nition.

/pdf/international-myeloma-working-group-updated-criteria-for-the-10zqd5hivp.pdf

International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma.

Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

/pdf/a-review-of-single-phase-improved-power-quality-ac-dc-2pm6h4zjxq.pdf

A review of single-phase improved power quality AC-DC converters

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

/pdf/light-emitting-diodes-ubzde6g9qc.pdf

Light-emitting diodes

Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.

Comprehensive Study of Single-Phase AC-DC Power Factor Corrected Converters With High-Frequency Isolation

In this paper, a new family of one-switch nonresonant power converter topologies, that can be used in fluorescent lamp ballasts are presented, and their selection criteria and design methodology are established. The proposed topologies include only one magnetic device (a tapped-inductor) in the power topology. They are specially suitable to implement low cost ballasts for low power fluorescent lamps supplied from a low DC input voltage. The design methodology is focused in obtaining regulated luminous flux in the lamp, by regulating the power delivered to the lamp against variations in the input voltage and lamp characteristic. The design criteria to select the most appropriate control method and guides to obtain the best operating point depending on the desired output characteristic are presented. Finally, the complete design process is described.

A new family of one-switch topologies for low input voltage fluorescent lamp ballast's: tapped-inductor-inverters selection criteria and design methodology

A systematic methodology to obtain large signal and small signal models of resonant inverters is presented in this paper. The models are intended to implement electronic ballast operating in closed-loop mode, thus improving ballast performance. A complete example obtaining large and small signal models for an LC parallel resonant inverter is provided, together with some simulation and experimental results, which validate the proposed methodology.

Dynamic modeling of high frequency resonant inverters for the implementation of closed loop electronic ballasts

In this paper the influence of the frequency on the starting voltage and dimming of compact fluorescent lamps is evaluated. The effects of the frequency on magnetic and drivers for frequencies above of 1 MHz are considered. Experimental results indicate that the starting voltage is lower for higher frequencies. Dimming results were not conclusive and no significant changes was observed. The converter used to drive the lamp was the class E amplifier using a capacitive impedance inverter as resonant tank.

http://ieeexplore.ieee.org/iel5/8625/27324/01216664.pdf

Electronic ballasts for CFL operating at frequencies above of 1 MHz: design considerations and behavior of the lamp

This paper presents an electronic ballast to operate HO fluorescent lamps with power ratings of 24 W, 39 W and 49 W. The proposed circuit detects the lamp type by its operation voltage and sets duty cycle of the power factor correction circuit to adequate the output power. Experimental results are shown to demonstrate the feasibility of the proposed solution.

Automatic lamp detection technique for fluorescent lamps electronic ballasts

In this paper a single-stage high-power-factor high-efficiency electronic ballast for compact fluorescent lamps is presented. The proposed topology use two voltage sources connected in series to feed the inverter that ballasting the lamp, one of them consists in the rectified line voltage and the other is a flyback converter operating in DCM. In this way the flyback converter processes a lower energy than the nominal power of the lamp. The proposed topology presents simplicity, high-power-factor, low current crest factor and high efficiency.

J.M. Alonso

Papers

A new family of one-switch topologies for low input voltage fluorescent lamp ballast's: tapped-inductor-inverters selection criteria and design methodology

Dynamic modeling of high frequency resonant inverters for the implementation of closed loop electronic ballasts

Electronic ballasts for CFL operating at frequencies above of 1 MHz: design considerations and behavior of the lamp

Automatic lamp detection technique for fluorescent lamps electronic ballasts

An efficient integrated electronic ballast for compact fluorescent lamps