142 research outputs found
A CubeSat for Calibrating Ground-Based and Sub-Orbital Millimeter-Wave Polarimeters (CalSat)
We describe a low-cost, open-access, CubeSat-based calibration instrument
that is designed to support ground-based and sub-orbital experiments searching
for various polarization signals in the cosmic microwave background (CMB). All
modern CMB polarization experiments require a robust calibration program that
will allow the effects of instrument-induced signals to be mitigated during
data analysis. A bright, compact, and linearly polarized astrophysical source
with polarization properties known to adequate precision does not exist.
Therefore, we designed a space-based millimeter-wave calibration instrument,
called CalSat, to serve as an open-access calibrator, and this paper describes
the results of our design study. The calibration source on board CalSat is
composed of five "tones" with one each at 47.1, 80.0, 140, 249 and 309 GHz. The
five tones we chose are well matched to (i) the observation windows in the
atmospheric transmittance spectra, (ii) the spectral bands commonly used in
polarimeters by the CMB community, and (iii) The Amateur Satellite Service
bands in the Table of Frequency Allocations used by the Federal Communications
Commission. CalSat would be placed in a polar orbit allowing visibility from
observatories in the Northern Hemisphere, such as Mauna Kea in Hawaii and
Summit Station in Greenland, and the Southern Hemisphere, such as the Atacama
Desert in Chile and the South Pole. CalSat also would be observable by
balloon-borne instruments launched from a range of locations around the world.
This global visibility makes CalSat the only source that can be observed by all
terrestrial and sub-orbital observatories, thereby providing a universal
standard that permits comparison between experiments using appreciably
different measurement approaches
Flexible demand in the GB domestic electricity sector in 2030
In order to meet greenhouse gas emissions targets the Great Britain (GB) future electricity supply will
include a higher fraction of non-dispatchable generation, increasing opportunities for demand side management
to maintain a supply/demand balance. This paper examines the extent of flexible domestic
demand (FDD) in GB, its usefulness in system balancing and appropriate incentives to encourage consumers
to participate. FDD, classified as electric space and water heating (ESWH), and cold and wet appliances,
amounts to 59 TW h in 2012 (113 TW h total domestic demand) and is calculated to increase to
67 TW h in 2030. Summer and winter daily load profiles for flexible loads show significant seasonal
and diurnal variations in the total flexible load and between load categories. Low levels of reflective consumer
engagement with electricity consumption and a resistance to automation present barriers to effective
access to FDD. A value of £1.97/household/year has been calculated for cold appliance loads used for
frequency response in 2030, using 2013 market rates. The introduction of smart meters in GB by 2020
will allow access to FDD for system balancing. The low commercial value of individual domestic loads
increases the attractiveness of non-financial incentives to fully exploit FDD. It was shown that appliance
loads have different characteristics which can contribute to an efficient power system in different ways.
� 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/3.0/)
Quantification of Savings for the European Transport Sector through Energy Efficient Urban Planning
The transport sector accounts for around 30 % of Europe’s final energy consumption. To meet the EU’s decarbonization goals by 2050, it is important to quantify the energy savings potential in technology, infrastructure, and planning. This study analyses the European transport sector in the context of traditional and energy-efficient urban development. The latter demonstrates a scenario where accessibility is provided through enhanced proximity to a destination rather than through increased mobility, where mobility is shifted from roads and aviation towards rail. This development is ensured by, among other things, investing heavily in urban and inter-urban transport systems and abstaining from building new freeways and airports. The results indicate that it is not only desirable but economically beneficial to shift towards an energy-efficient transport system. The development of the European transport sector in the proposed trajectory significantly reduces annual final energy demand, and the investment made in new infrastructure for rail, bikes, and walkable urban areas are paid back by the reduced cost from road transport
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