The Casimir Effect from a Condensed Matter Perspective

The Casimir effect, a key observable realization of vacuum fluctuations, is usually taught in graduate courses on quantum field theory. The growing importance of Casimir forces in microelectromechanical systems motivates this subject as a topic for graduate many-body physics courses. To this end, we revisit the Casimir effect using methods common in condensed matter physics. We recover previously derived results and explore the implications of the analogies implicit in this treatment.Comment: Accepted for Publication in American Journal of Physic

ISS RADIATION ENVIRONMENT AS OBSERVED BY LIULIN TYPE-R3DR2 INSTRUMENT IN OCTOBER-NOVEMBER 2014

Space radiation was monitored using the R3DR2 spectrometer-dosimeter during the flight outside the Russian “Zvezda” module of ISS in October-November 2014. The instrument was mounted on the ESA EXPOSE-R2 platform. The R3DR2 instrument was first developed and used during the flight of ESA EXPOSE-R platform in 2009-2010 (Dachev et al, 2015a). It is a low mass, small dimension automated device that measures solar visible and ultraviolet (UV) radiation in four channels and ionizing radiation in 256 channels of a Liulin-type energy deposition spectrometer (Dachev et al, 2002). Ionizing radiation was measured and separated in 256 deposited energy spectra, which were further used for determination of the absorbed dose rate and flux. The main results obtained by the R3DR2 instrument are: (1) three different radiation sources were detected and quantified - galactic cosmic rays (GCR), energetic protons from the inner radiation belt (IRB) in the region of the South Atlantic anomaly and energetic electrons from the outer radiation belt (ORB); (2) for the first time in the history of using of the Liulin-type energy deposition spectrometers (Dachev et al, 2015b) an observable flux from solar energetic particles (SEP) was detected in the period 1-4 November 2014; (3) the obtained SEP energy deposition spectra were compared with other spectra to confirm their shape

Pre-engineering Spaceflight Validation of Environmental Models and the 2005 HZETRN Simulation Code

The HZETRN code has been identified by NASA for engineering design in the next phase of space exploration highlighting a return to the Moon in preparation for a Mars mission. In response, a new series of algorithms beginning with 2005 HZETRN, will be issued by correcting some prior limitations and improving control of propagated errors along with established code verification processes. Code validation processes will use new/improved low Earth orbit (LEO) environmental models with a recently improved International Space Station (ISS) shield model to validate computational models and procedures using measured data aboard ISS. These validated models will provide a basis for flight-testing the designs of future space vehicles and systems of the Constellation program in the LEO environment

Methodology for assessment and analysis the geomechanical state of the opencast mining operations built up in the rock masses

Ensuring the stability of constructive elements (rock flanks or benches) in the opencast pits and quarries is carried out in a different way, and this is often the reason of considering only separate parameters to be taken. Such assessments are often made using the different hypotheses and formulae such as those of Tsimbarevich, Fellenius, Maslov, Fisenko, etc. The key factors, influencing such assessments together and separately, are numerous and in most cases it is difficult to gather them together with one summarized formula. This paper presents a structured uniform methodology in order to provide an approach for assessment targeting the geomechanical state of the opencast mining operations , situated in the homogeneous rock masses

Radiation Environment In Earth-Moon Space: Results From RADOM Experiment Onboard Chandrayaan-1

The Radiation Monitor (RADOM) payload is a miniature dosimeter-spectrometer onboard Chandrayaan-1 mission for monitoring the local radiation environment in near-Earth space and in lunar space. RADOM measured the total absorbed dose and spectrum of the deposited energy from high energy particles in near-Earth space, en-route and in lunar orbit. RADOM was the first experiment to be switched on soon after the launch of Chandrayaan-1 and was operational till the end of the mission. This paper summarizes the observations carried out by RADOM during the entire life time of the Chandrayaan-1 mission and some the salient results.Comment: Accepted for publication in Advances in Geoscience

Thermospheric heating at high latitudes as observed from intercosmos-Bulgaria-1300 and dynamics explorer-B

This paper reports the results of the first direct comparison of near simultaneous measurements obtained by the INTERCOSMOS-BULGARIA-1300 and the DYNAMICS EXPLORER-B satellites. The ICB-1300 is in a near circular orbit at a mean height of about 850 km. The DE-B satellite in an elliptical orbit is sometimes directly below the ICB-1300 satellite providing an opportunity to investigate the response of the thermosphere to particle fluxes from the magnetosphere. Energy fluxes in the range 0.2-15 keV are obtained from an energetic particle analyzer on board the ICB-1300 satellite. The thermospheric composition and density are obtained by a neutral gas mass spectrometer (NACS) on the DE-B satellite. During the period 20 August-20 November, 1981, observations show tht the times and locations of maxima in magnetospheric energy deposition coincide with regions of maximum thermospheric upwelling characterized by composition changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25883/1/0000446.pd

EVOLUTION OF SANDY BEACH IN THE CITY OF VARNA

The article represents a retrospective review of long time research of genesis and development of the Central beach in the City of Varna which makes possible a forecast of its further development. Both natural and anthropogenic impact on the beach evolution is taken into consideration. It is ascertained that construction of coastal protection structures at the northern part of the beach in 80’s resulted in cessation of natural beach area growth. The strengthen of a breakwater in the main port and illegal building also contributed to considerable coast recession and beach volume reducing. Because of this a recreational potential of the Central beach is gradually decreasing. New method named “cross-shore sediment bypassing” is suggested to reduce the negative trend.</jats:p