29,479 research outputs found
[Book Review of] \u3cem\u3eEthics in Medicine: Historical Perspectives and Contemporary Concerns\u3c/em\u3e, edited by Stanley J. Reiser, Arthur J. Dyck, and William J. Curran
Human Trafficking and Terrorism: Utilizing National Security Resources to Prevent Human Trafficking in the Islamic State
Human Trafficking and Terrorism: Utilizing National Security Resources to Prevent Human Trafficking in the Islamic State
This is a report of a Masterâs thesis done in behalf of the local network in Stockholm, under Fortum Distribution AB. The thesis was to conduct a review of a distribution station named Fs MyrĂ€ngen located in TĂ€by. A model was created for the 11 kV network linked to the secondary side of Fs MyrĂ€ngen. Based on this model and using symmetrical components, theoretical fault currents (short circuit and ground fault) could be calculated. The results of these fault currents are used to investigate and develop new settings for relay protection and ground equipment in the station. The results of the calculated fault currents were also used to investigate unwanted voltages that occurs for grounded parts due to earth faults. The value of these unwanted voltages was then compared to heavy current regulations developed by the Electrical Safety Authority in Sweden. Another element of the work was to create a rehabilitation plan for the structure on the 11 kV side of Fs MyrĂ€ngen, the main goal regarding the rehabilitation plan was to investigate the advantages and disadvantages that exist at a possible transition to numerical protection relays. This was done by making a market overview of the different types of numerical protection relays and compare these with the existing analog protective device in Fs MyrĂ€ngen. The study showed that protective relay settings should be revised according to the recommendations in the report, ground equipment should be replaced with a self-regulating type, transformers should be replaced due to age and capacity limitations. Regarding a switch to numerical protection relays the type REF615 from ABB was recommended, in that case the control board in the station should be replaced to a station computer. Furthermore should current transformers be replaced to recive a desired sensitivity regarding detection of ground faults. The report also showed that Fs MyrĂ€ngen meets the regulations of unwanted voltages over grounded parts in distribution stations due to earth faults.Detta Ă€r en rapport av ett examensarbete utfört i uppdrag av lokalnĂ€t Stockholm under Fortum Distribution AB. Examensarbetet gick ut pĂ„ att göra en översyn av en fördelningsstation vid namn Fs MyrĂ€ngen som Ă€r belĂ€gen i TĂ€by. En modell skapades av 11 kV nĂ€tet kopplat till Fs MyrĂ€ngen, utifrĂ„n denna modell samt med hjĂ€lp av symmetriska komponenter berĂ€knades teoretiska felströmmar bĂ„de för kortslutning och jordslutning. Resultaten av dessa felströmmar anvĂ€ndes för att utreda och ta fram instĂ€llningar pĂ„ relĂ€skydd och nollpunktsutrustning i stationen. Resultaten pĂ„ framrĂ€knade jordfelsströmmar anvĂ€ndes Ă€ven för att utreda vilken spĂ€nningssĂ€ttning som uppstĂ„r vid jordfel, i de nĂ€tstationer som matas av Fs MyrĂ€ngen. SpĂ€nningssĂ€ttningen pĂ„ nĂ€tstationerna jĂ€mfördes sedan med de starkströmsföreskrifter som Ă€r framtagna av elsĂ€kerhetsverket. Ett annat moment i arbetet var att skapa en upprustningsplan för skyddsanordningen pĂ„ 11 kV sidan i Fs MyrĂ€ngen, huvudmĂ„let för den biten var att utreda vilka fördelar och nackdelar som finns vid en eventuell övergĂ„ng till numeriska skydd. Detta gjordes genom att göra en marknadsöversikt över olika typer av numeriska relĂ€skydd, samt jĂ€mföra dessa med den befintliga skyddsanordningen i MyrĂ€ngen som Ă€r av analog typ. Studien visade att relĂ€skyddsinstĂ€llningar bör ses över enligt rekommendationer i rapporten, nollpunktsutrustningen bör bytas ut till sjĂ€lvreglerande typ, transformatorerna bör bytas ut p.g.a. Ă„lder och kapacitetsbegrĂ€nsning. GĂ€llande skyddsanordningen rekommenderas en övergĂ„ng till numeriska skydd av typen REF615, och i samband med detta byta ut den befintliga kontrolltavlan i stationen till en stationsdator. Vidare bör Ă€ven strömtransformatorer för jordfelsskydden bytas ut för att uppnĂ„ önskad kĂ€nslighet gĂ€llande detektering av jordfel. För spĂ€nningssĂ€ttning av nĂ€tstationer vid jordfel, visar resultaten att stationen uppfyller kraven enligt starkströmsföreskrifterna frĂ„n elsĂ€kerhetsverket
[Book Review of] \u3cem\u3eMaking Medical Choices: Who Is Responsible?\u3c/em\u3e by Jane J. Stein
Classical Statistics Inherent in a Quantum Density Matrix
A density matrix formulation of classical bipartite correlations is
constructed. This leads to an understanding of the appearance of classical
statistical correlations intertwined with the quantum correlations as well as a
physical underpinning of these correlations. As a byproduct of this analysis, a
physical basis of the classical statistical correlations leading to additive
entropy in a bipartite system discussed recently by Tsallis et al emerges as
inherent classical spin fluctuations. It is found that in this example, the
quantum correlations shrink the region of additivity in phase space.Comment: 10 pages, 3 figure
Entanglement and optimal strings of qubits for memory channels
We investigate the problem of enhancement of mutual information by encoding
classical data into entangled input states of arbitrary length and show that
while there is a threshold memory or correlation parameter beyond which
entangled states outperform the separable states, resulting in a higher mutual
information, this memory threshold increases toward unity as the length of the
string increases. These observations imply that encoding classical data into
entangled states may not enhance the classical capacity of quantum channels.Comment: 14 pages, 8 figures, latex, accepted for publication in Physical
Review
- âŠ