| 1. |
- Tinetti, Giovanna, et al.
(författare)
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The science of EChO
- 2010
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Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 6:S276, s. 359-370
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Tidskriftsartikel (refereegranskat)abstract
- The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life. The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole. EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates. © International Astronomical Union 2011.
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| 2. |
- James, P. A. B., et al.
(författare)
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Implications of the UK field trial of building mounted horizontal axis micro-wind turbines
- 2010
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 38:10, s. 6130-6144
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Tidskriftsartikel (refereegranskat)abstract
- Building mounted micro-wind turbines and photovoltaics have the potential to provide widely applicable carbon free electricity generation at the building level. Photovoltaic systems are well understood and it is easy to predict performance using software tools or widely accepted yield estimates. Micro-wind, however, is far more complex and in comparison poorly understood. This paper presents the key findings of the building mounted (<2 kWp) turbine component of the UK micro-wind trial undertaken by the Energy Saving Trust in 2008/09. The monitored performance of 39 horizontal axis turbines in urban, suburban and rural locations is discussed alongside the accuracy of predictive wind speed tools for the sites. The performance of urban and suburban micro-wind sites in the trial was poor with annual generation of less than 75 kWh/m2 swept area, the majority of which were less than 25 kWh/m2. Good rural sites had an annual generation of between 100 and 280 kWh/m2, far less than the nominal 360 kWh/m2 (10% load factor for a typical turbine) that is often assumed. In the light of these findings, the potential impact of the UK’s latest policy instrument, the 2010 micro-generation tariffs, is considered for both micro-wind and photovoltaics.
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| 3. |
- Sissons, M. F., et al.
(författare)
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Pole-mounted horizontal axis micro-wind turbines : UK field trial findings and market size assessment
- 2011
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 39:6, s. 3822-3831
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the key findings of the pole-mounted turbine (2.5–6 kWp) component of the UK micro-wind trial. The real world performance of horizontal axis turbines is compared with yield estimates based on site wind speed prediction. The distribution of UK agricultural farms is overlaid with wind resource mapping to estimate the number of potential agricultural farm sites for micro-wind. The yield performance of turbines during the monitoring period was observed to be very close to that predicted by NOABL–MCS wind speed estimates. Based on an installation criterion of a maximum 12 year payback time, with a 6% discount rate and micro-generation feed in tariffs available, there are ∼87,000 farm sites for micro-wind in the UK. If 10% of these farms were to install micro-wind turbines (to a capacity of 48 kWp per farm) this would correspond to a capacity of 418 MWp, with an annual generation yield of 1025 GWh, comparable to that of a large, on shore wind farm in the UK. It should be noted that the feed in tariff considered in this paper is that available in the UK in 2011, which, at 26.7 p/kWh (∼30 Euro cents/kWh) represents a significant subsidy.
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| 4. |
- Gultepe, Ismail, et al.
(författare)
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Ice fog in arctic during fram-ice fog project aviation and nowcasting applications
- 2014
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 95:2, s. 211-226
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Tidskriftsartikel (refereegranskat)abstract
- Increased understanding of ice fog microphysics can improve frost and ice fog prediction using forecast models and remote-sensing retrievals, thereby reducing potential hazards to aviation
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| 5. |
- Bourikas, Leonidas, et al.
(författare)
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Addressing the challenge of interpreting microclimatic weather data collected from urban sites
- 2013
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Ingår i: Journal of Energy and Power Engineering. - : Scientific Research Publishing, Inc.. - 1934-8975 .- 1934-8983. ; 1:5, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents some installation and data analysis issues from an ongoing urban air temperature and humidity measurement campaign in Hangzhou and Ningbo, China. The location of the measurement sites, the positioning of the sensors and the harsh conditions in an urban environment can result in missing values and observations that are unre-presentative of the local urban microclimate. Missing data and erroneous values in micro-scale weather time series can produce bias in the data analysis, false correlations and wrong conclusions when deriving the specific local weather patterns. A methodology is presented for the identification of values that could be false and for determining whether these are “noise”. Seven statistical methods were evaluated in their performance for replacing missing and erroneous values in urban weather time series. The two methods that proposed replacement with the mean values from sensors in locations with a Sky View Factor similar to that of the target sensor and the sensors closest to the target’s location per-formed well for all Day-Night and Cold-Warm days scenarios. However, during night time in warm weather the re-placement with the mean values for air temperature of the nearest locations outperformed all other methods. The results give some initial evidence of the distinctive urban microclimate development in time and space under different regional weather forcings.
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| 6. |
- Nowack, Bernd, et al.
(författare)
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Potential scenarios for nanomaterial release and subsequent alteration in the environment
- 2012
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 31:1, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- The risks associated with exposure to engineered nanomaterials (ENMs) will be determined in part by the processes that control their environmental fate and transformation. These processes act not only on ENMs that might be released directly into the environment, but more importantly also act on ENMs in consumer products and those that have been released from the product. The environmental fate and transformation is likely to differ significantly for each of these cases. The ENM released from actual direct use or from nano-containing products are much more relevant for ecotoxicological studies and risk assessment than pristine ENMs. The released ENMs may have a greater or lesser environmental impact than the starting materials, depending on the transformation reactions and the material. Almost nothing is known about the environmental behavior and the effects of released and transformed ENMs, although these are the materials that are actually present in the environment. Further research is needed to show if the release and transformation processes result in a similar or more diverse set of ENMs and ultimately how this affects environmental behavior. These questions are addressed in this article using four brief hypothetical case studies that cover a wide range of ENMs, their direct use or product applications, and their likely fate in the environment. Furthermore, a more definitive classification scheme for ENMs should be adopted that reflects their surface condition, which is a result of both industrial and environmental processes acting on the ENM. The authors conclude that it is not possible to assess the risks associated with the use of ENMs by investigating only the naked (pristine) form of the ENM, without considering alterations and transformation processes. Environ. Toxicol. Chem. © 2011 SETAC.
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| 7. |
- Ellis, A. D., et al.
(författare)
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Future Directions to Realize Ultra-High Bit-Rate Transmission Systems
- 2010
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Ingår i: Proceedings of OptoElectronics and Communications Conference, OECC 2010, Sapporo, Japan, 5-9 July 2010, invited paper..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we examine two potential future directions for the realization of ultra-high bit rate transmission systems.
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| 8. |
- Mlynczak, Martin G., et al.
(författare)
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Atomic oxygen in the mesosphere and lower thermosphere derived from SABER : Algorithm theoretical basis and measurement uncertainty
- 2013
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Ingår i: Journal of Geophysical Research - Atmospheres. - : American Geophysical Union (AGU). - 2169-897X .- 2169-8996. ; 118:11, s. 5724-5735
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Tidskriftsartikel (refereegranskat)abstract
- Atomic oxygen (O) is a fundamental component in chemical aeronomy of Earth's mesosphere and lower thermosphere region extending from approximately 50 km to over 100 km in altitude. Atomic oxygen is notoriously difficult to measure, especially with remote sensing techniques from orbiting satellite sensors. It is typically inferred from measurements of the ozone concentration in the day or from measurements of the Meinel band emission of the hydroxyl radical (OH) at night. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite measures OH emission and ozone for the purpose of determining the O-atom concentration. In this paper, we present the algorithms used in the derivation of day and night atomic oxygen from these measurements. We find excellent consistency between the day and night O-atom concentrations from daily to annual time scales. We also examine in detail the collisional relaxation of the highly vibrationally excited OH molecule at night measured by SABER. Large rate coefficients for collisional removal of vibrationally excited OH molecules by atomic oxygen are consistent with the SABER observations if the deactivation of OH(9) proceeds solely by collisional quenching. An uncertainty analysis of the derived atomic oxygen is also given. Uncertainty in the rate coefficient for recombination of O and molecular oxygen is shown to be the largest source of uncertainty in the derivation of atomic oxygen day or night.
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| 9. |
- Mlynczak, Martin G., et al.
(författare)
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Observations of infrared radiative cooling in the thermosphere on daily to multiyear timescales from the TIMED/SABER instrument
- 2010
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 115:A3
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Tidskriftsartikel (refereegranskat)abstract
- We present observations of the infrared radiative cooling by carbon dioxide (CO2) and nitric oxide (NO) in Earth's thermosphere. These data have been taken over a period of 7 years by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W m−3), radiative fluxes (W m−2), and radiated power (W). In the period from January 2002 through January 2009, we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle 23. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short-term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO2, with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO2 15 μm and the NO 5.3 μm vibration-rotation bands. The observed NO and CO2 cooling rates have been compiled into a separate data set and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models.
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| 10. |
- Parmigiani, Francesca, et al.
(författare)
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All-Optical Phase Regeneration of 40Gbit/s DPSK Signals in a Black‐Box Phase Sensitive Amplifier
- 2010
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Ingår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010; San Diego, CA; United States; 21 March 2010 through 25 March 2010. - 9781557528841 ; , s. PDPC3-
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Konferensbidrag (refereegranskat)abstract
- We present a black‐box four wave mixingbased bit‐rate‐flexible phase sensitive amplifier and use it in the first demonstration of 40 Gbit/s DPSK phaseregeneration.
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