Lightning current detector

An apparatus for measuring the intensity of current produced in an elongated electrical conductive member by a lightning strike for determining the intensity of the lightning strike is presented. The apparatus includes an elongated strip of magnetic material that is carried within an elongated tubular housing. A predetermined electrical signal is recorded along the length of said elongated strip of magnetic material. One end of the magnetic material is positioned closely adjacent to the electrically conductive member so that the magnetic field produced by current flowing through said electrically conductive member disturbs a portion of the recorded electrical signal directly proportional to the intensity of the lightning strike

Development of lightning current detector

A lightning current detector to record the maximum current amplitude of a lightning strike to the 150 meter weather tower at KSC was developed. The principle of operation of the detector is discussed, materials chosen to build the detector are described, and calibration tests performed on the detector are given. Field results of the detectors from two separate lightning strikes to the tower are included

Natural ventilation of multiple storey buildings: The use of stacks for secondary ventilation

The natural ventilation of buildings may be enhanced by the use of stacks. As well as increasing the buoyancy pressure available\ud to drive a flow, the stacks may also be used to drive ventilation in floors where there is little heat load. This is achieved by connecting\ud the floor with a relatively low heat load to a floor with a higher heat load through a common stack. The warm air expelled from the\ud warmer space into the stack thereby drives a flow through the floor with no heat load. This principle of ventilation has been adopted\ud in the basement archive library of the new SSEES building at UCL. In this paper a series of laboratory experiments and supporting\ud quantitative models are used to investigate such secondary ventilation of a low level floor driven by a heat source in a higher level\ud floor. The magnitude of the secondary ventilation within the lower floor is shown to increase with the ratio of the size of the\ud openings on the lower to the upper floor and also the height of the stack. The results also indicate that the secondary ventilation\ud leads to a reduction in the magnitude of the ventilation through the upper floor, especially if the lower floor has a large inlet area.\ud r 2005 Elsevier Ltd. All rights reserve

New insights into the regulatory pathways associated with the activation of the stringent response in bacterial resistance to the PBP2-targeted antibiotics, mecillinam and OP0595/RG6080

Objectives: The diazabicyclooctane β-lactamase inhibitor OP0595 (RG6080) also acts as an antibiotic, targeting PBP2 in Enterobacteriaceae, but this activity is vulnerable to mutational resistance. We used WGS to investigate the basis of this resistance. Methods: Twenty OP0595-selected mutants, comprising four derived from each of five different Escherichia coli strains, were sequenced on Illumina HiSeq. Reads from each mutant were mapped to the assembled genome of the corresponding parent. A variant-calling file generated with Samtools was parsed to determine genetic alterations. Results: Besides OP0595, the mutants consistently showed decreased susceptibility to mecillinam, which likewise targets PBP2, and grew as stable round forms in the presence of subinhibitory concentrations of OP0595. Among the 20 mutants, 18 had alterations in genes encoding tRNA synthase and modification functions liable to induce expression of the RpoS sigma factor through activation of the stringent response or had mutations suppressing inactivators of RpoS or the stringent response signal-degrading enzyme, SpoT. TolB was inactivated in one mutant: this activates RcsBC regulation and was previously associated with mecillinam resistance. The mechanism of resistance remained unidentified in one mutant. Both the RpoS and RcsBC systems regulate genes of cell division, including ftsAQZ that can compensate for loss or inhibition of PBP2, allowing survival of the challenged bacteria as stable round forms, as seen. Conclusions: WGS identified the global stringent response signal, entailing induction of RpoS, as the main mediator of mutational resistance to OP0595 in E. coli

HST followup observations of two bright z ~ 8 candidate galaxies from the BoRG pure-parallel survey

We present followup imaging of two bright (L > L*) galaxy candidates at z > 8 from the Brightest of Reionizing Galaxies (BoRG) survey with the F098M filter on HST/WFC3. The F098M filter provides an additional constraint on the flux blueward of the spectral break, and the observations are designed to discriminate between low- and high-z photometric redshift solutions for these galaxies. Our results confirm one galaxy, BoRG 0116+1425 747, as a highly probable z ~ 8 source, but reveal that BoRG 0116+1425 630 - previously the brightest known z > 8 candidate (mAB = 24.5) - is likely to be a z ~ 2 interloper. As this source was substantially brighter than any other z > 8 candidate, removing it from the sample has a significant impact on the derived UV luminosity function in this epoch. We show that while previous BoRG results favored a shallow power-law decline in the bright end of the luminosity function prior to reionization, there is now no evidence for departure from a Schechter function form and therefore no evidence for a difference in galaxy formation processes before and after reionization.Comment: Accepted by ApJL, 7 pages, 4 figure

Dephasing Effect in Photon-Assisted Resonant Tunneling through Quantum Dots

We analyze dephasing in single and double quantum dot systems. The decoherence is introduced by the B\"{u}ttiker model with current conserving fictitious voltage leads connected to the dots. By using the non-equilibrium Green function method, we investigate the dephasing effect on the tunneling current. It is shown that a finite dephasing rate leads to observable effects. The result can be used to measure dephasing rates in quantum dots.Comment: 4 pages, 3 figures, to be published in Rapid Communications of Phys. Rev.

Faculty Perceptions Of Student Credibility Based On Email Addresses

The purpose of this study was to evaluate faculty perceptions of student credibility based on email addresses.  The survey was conducted at an upper division business school in Michigan where all students have completed at least two years of college courses.   The survey results show that a student’s selection of an email address does influence the faculty’s perception of their credibility.  An email address that consists of a nickname reduces the faculty’s perception of student credibility as well as the domain name of the email service used by the student   The reduced credibility  may have a negative impact on the faculty member’s perception of the student.

Student Perceptions Of Faculty Credibility Based On Email Addresses

The purpose of this study was to evaluate students’ perceptions of faculty credibility based on email addresses.  The survey was conducted at an upper division business school in Michigan where all students have completed at least two years of college courses.   The survey results show that a faculty member’s selection of an email address does influence the student’s perception of faculty credibility.  An email address that consists of a nickname reduces the student’s perception of faculty credibility.  The reduced creditability may have a negative impact on the faculty member as well as the college.&nbsp