Design parameters and measured performance of the IRAM 30-mMillimeter Radio Telescope

The “Millimeter Radio Telescope” (MRT) is operated by the Institute for Radio Astronomy in the millimeter range (IRAM) and is located at 2850-m altitude in the Sierra Nevada, near Granada, Spain. It is a reflector antenna of 30-m diameter with a surface accuracy of 0.08 mm and a pointing accuracy of better than 2 arcsec. The telescope is equipped with sensitive receivers for the atmospheric windows between 0.8- and 7-mm wavelength. The authors describe the optics layout of the receiver and calibration system, which allows simultaneous observations at a number of frequencies. The special design aspects of the antenna, in particular the control of thermal deformations and the achievement of a high reflector and pointing accuracy are described. The authors compare the design computations with the characteristics of the telescope, derived from several years of operation and optimization. The success of the design is demonstrated by observational experience. The authors conclude the paper with a short review of some of the astronomical results obtained with the telescope     

Settlement as a driver for sewer rehabilitation

This paper assesses the influence of (differential) settlement on sewer system functioning. Based on historical data of the vertical position of sewer invert levels, tilt measurements and in-sewer inspection videos, settlement and settlement related influences are analyzed for a case study area in Amsterdam. The average settlement rate of this system was 4 mm/year. Given this settlement rate, it is shown that settlement significantly influences sewer system functioning within the lifetime of a sewer (system).     

Organizational Characteristics Influencing SME Information Security Maturity

In the current business environment, many organizations use popular standards such as the ISO 27000x series, COBIT, and related frameworks to protect themselves against security incidents. However, these standards and frameworks are overly complicated for small to medium-sized enterprises, leaving these organizations with no easy to understand toolkit to address their security needs. This research builds upon the recent Information Security Focus Area Maturity (ISFAM) model for SME information security as a cornerstone in the development of an assessment tool for tailor-made, fast, and easy-to-use information security advice for SMEs. By performing an extensive literature review and evaluating the results with security experts, we propose the Characterizing Organizations’ Information Security for SMEs (CHOISS) model to relate measurable organizational characteristics in four categories through 47 parameters to help SMEs distinguish and prioritize which risks to mitigate.     

Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes

In this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modeled with the single-phase approach and the simulation results are compared with correlations from experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO₂ nanoparticles are used as nanofluid with particle volume concentrations ranging from 0% to 10%. Nusselt number predictions for the nanofluid are in agreement with experimental results and a conventional single-phase correlation. The mean deviation is in the range of ?5%. Friction factor values show a mean deviation of 0.5% to a conventional single-phase correlation, however, they differ considerably from the nanofluid experimental data. The results indicate that the nanofluid requires more pumping power than the base fluid for high particle concentrations and Reynolds numbers on the basis of equal heat transfer rate.     

Cognitive versus inference..

Expresses reservations concerning not the content but the vocabulary used by R. B. Zajonc in his article on feeling and thinking (see record 1980-09733-001). The vocabulary serves to perpetuate a pervasive confusion among several legitimate senses of the words cognitive and inference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radiation cones from feed-support struts of symmetric paraboloidal antennas

Wide-angle radiation associated with the plane-wave component of the field in the focal space of a paraboloidal reflector is computed by integrating the currents induced on the feed-support struts. This component of radiation is locally maximum on radiation cones which lie along the axis of each strut. Comparison with data measured for the Dwingeloo radio telescope indicates good agreement for the position, width, and intensity of these cones, even at levels 50 dB below the peak of the main beam.     

Thermal Conductivity of Aqueous Sugar Solutions under High Pressure

Molecular energy transport in aqueous sucrose and glucose solutions of different mass fractions and temperatures is investigated up to 400 MPa, using the transient hot-wire method. The results reveal an increasing thermal conductivity with increasing pressure and decreasing mass fraction of sugar. No significant differences between sucrose and glucose solutions were observed. Different empirical and semi-empirical relations from the literature are discussed to describe and elucidate the behavior of the solutions with pressure. The pressure-induced change of the thermal conductivity of sugar solutions is mainly caused by an increase of the thermal conductivity and the decrease of molar volume of the water fraction. A simple pressure adapted mass fraction model permits an estimation of the thermal conductivity of the investigated solutions within an uncertainty of about 3%. An erratum to this article can be found at