Low-Voltage Circuit-Breaker Behavior under Overload Conditions

This article deals with temperature-rise of current path of modern low-voltage circuit-breaker with rotary contact system at overloads and subsequent experimental verification of selected model. The first part describes optimal setting of input conditions of simulation and mainly transient phenomena at contacts causing dynamic change of contact resistances due to change of total contact force, a new challenge to be solved in this contribution. The second part devotes laboratory measurement on prepared sample of the breaker for verification of transient simulation. These simulations are not only important for understanding of rotary system behavior under overloads, but forms an essential part of R & D process due to the speed-up of optimal current path design. In the end, both the financial costs and time effort could be decreased

Diagnostics of Various Phenomena in LV Devices Under Real Switching Conditions

The article deals with issues to be tackled when performing experiments with low voltage devices under real switching conditions and subsequently discusses various phenomena in an experimental device. The first part describes optimum setting of diagnostic equipment - mainly for optical diagnostic methods. The second part describes some phenomena encountered during switching process under real switching conditions - arc roots movement (cathode and anode spots). These phenomena are not only important for experimental study itself but also form necessary input data for numerical models and their validation

Investigation of top mass measurements with the ATLAS detector at LHC

Several methods for the determination of the mass of the top quark with the ATLAS detector at the LHC are presented. All dominant decay channels of the top quark can be explored. The measurements are in most cases dominated by systematic uncertainties. New methods have been developed to control those related to the detector. The results indicate that a total error on the top mass at the level of 1 GeV should be achievable.Comment: 47 pages, 40 figure

Rotating Gliding Arc: Innovative Source for VOC Remediation

The large-scale plasma treatment of waste gas in industrial or municipal conditions requires high efficiency of plasma conversion process at high processing speed, i.e., large volumetric flow. The integration of the plasma unit into existing systems puts demands on the pipe-system compatibility and minimal pressure drop due to adoption of plasma processing step. These conditions are met at the innovative rotating electrode gliding arc plasma unit described in this article. The system consists of propeller-shaped high voltage electrode inside grounded metallic tube. The design of HV electrode eliminates the pressure drop inside the air system, contrary the plasma unit itself is capable of driving the waste gas at volumetric flow up to 300 m3/hr for 20 cm pipe diameter. In the article the first results on pilot study of waste air treatment will be given for selected volatile organic compounds together with basic characteristic of the plasma unit used

Investigation and Numerical Simulation of a High-Current AC Circuit Breaker

The article is devoted to the study of the high-current AC circuit breaker. The results of the study are presented for various configurations of the arc divider. The study includes methods of spectral diagnostics and high-speed camera shooting synchronized with the electrical characteristics of the circuit breaker (current, voltage) in time. The obtained results allow to determine the composition of the plasma and dynamics of changes in the composition of the discharge in time. Calculation of the plasma composition and properties is made according to the obtained data, which makes it possible to take into account the products of circuit breaker materials ablation in numerical simulation. Non-stationary two-dimensional mathematical model with a moving mesh is developed. The obtained results allow to correct and verify the developed mathematical model of the circuit breaker operation. The evaluation of the arc divider influence is presented in the article

Safety I to Safety II: A Paradigm Shift or More Work as Imagined?; Comment on “False Dawns and New Horizons in Patient Safety Research and Practice”

In their editorial, Mannion and Braithwaite contend that the approach to solving the problem of unsafe care, Safety I, is flawed and requires a shift in thinking to what they are calling Safety II. We have reservations as to whether by itself the shift from Safety I to Safety II is sufficient. Perhaps our failure to improve outcomes in the field of patient safety and quality lies less in our approach – Safety I vs. Safety II – and more in the lack of an agreed upon, commonly understood set of core competencies (knowledge, skills, and attitudes) needed in its workforce. The authors explore in this commentary the need to establish core competencies as part of the pathway to professionalism for the discipline of patient safety and quality

May the fourth be with you: a microarchitectural side channel attack on several real-world applications of Curve25519

Session D3: Logical Side ChannelsIn recent years, applications increasingly adopt security primitives designed with better countermeasures against side channel attacks. A concrete example is Libgcrypt’s implementation of ECDH encryption with Curve25519. The implementation employs the Montgomery ladder scalar-by-point multiplication, uses the unified, branchless Montgomery double-and-add formula and implements a constant-time argument swap within the ladder. However, Libgcrypt’s field arithmetic operations are not implemented in a constant-time side-channel-resistant fashion. Based on the secure design of Curve25519, users of the curve are advised that there is no need to perform validation of input points. In this work we demonstrate that when this recommendation is followed, the mathematical structure of Curve25519 facilitates the exploitation of side-channel weaknesses. We demonstrate the effect of this vulnerability on three software applications—encrypted git, email and messaging—that use Libgcrypt. In each case, we show how to craft malicious OpenPGP files that use the Curve25519 point of order 4 as a chosen ciphertext to the ECDH encryption scheme. We find that the resulting interactions of the point at infinity, order-2, and order-4 elements in the Montgomery ladder scalar-by-point multiplication routine create side channel leakage that allows us to recover the private key in as few as 11 attempts to access such malicious files.Daniel Genkin, Luke Valenta, Yuval Yaro

Understanding the contribution of metabolism to Mycobacterium tuberculosis drug tolerance

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Photonic band-gap effects on photoluminescence of silicon nanocrystals embedded in artificial opals

Si nanocrystals were formed in synthetic opals by Si-ion implantation and their optical properties studied using microphotoluminescence and reflection techniques. The properties of areas with high crystalline quality are compared with those of disordered regions of samples. The photoluminescencespectrum from Si nanocrystals embedded in silica spheres is narrowed by the inhibition of emission at wavelengths corresponding to the opalphotonic pseudoband gap (∼690 nm). Measurements of photoluminescencespectra from individual implanted silica spheres is also demonstrated and the number of emitting Si nanocrystals in single brightly emitting spheres is estimated to be of the order of one thousand.This work was supported by GACR (202/03/0789), NATO (PST.CLG.978100), and by the Royal Swedish Academy of Sciences. One of the authors ~J.V.! appreciates financial support from the French government (program Echange)