13,024 research outputs found
Can Plants Save Money: A Look At The Biowall
No full textThe objective of this research was to design, demonstrate, and monitor the Biowall; a novel system for improving indoor air quality in a residential building, which has the potential to save energy compared to traditional air quality control. The Biowall was integrated into the heating, ventilation, and air-conditioning system of a high performance home and utilized plants as a passive filter system to remove volatile organic compounds from the interior space of the home. The testing environment in this study was a 984 square foot efficient residential home constructed for the U.S. Department of Energy Solar Decathlon 2011 competition. A number of sensors were installed in the home to monitor the operation of the wall including temperature, relative humidity, carbon dioxide, and total volatile organic compound (TVOC) sensors. The main outcomes of the project included the design and construction of a test platform for the current study and future research, energy results that showed as high as 160% ventilation energy savings over a 1 week test period and $170 per year in projected cost savings versus a traditional ventilation strategy, and lessons learned and suggestions for future research
Aircraft Cabin Air Sampling Study: Part 1 of the Final Report
No full textThis report describes the methodology and results of a study of aircraft cabin air quality undertaken by Cranfield University and two contracted analytical laboratories on behalf of the Department for Transport (DfT). The project began in 2007 and was carried out under the leadership of the late Helen Muir OBE (Professor of Aerospace Psychology, Cranfield University) until her illness and untimely death in the first quarter of 2010. The authors and project team are indebted to Helen for her inspiring contribution that made this project and our report possible. She is sadly missed
Content and advertising in the media: pay-tv versus free-to-air
No full textWe compare the advertising intensity and content of programming in a market with competing media platforms. With pay-tv, media platforms have two sources of revenues, advertising revenues and revenues from viewers. With free-to-air, media platforms receive all revenues from advertising. We show that if viewers strongly dislike advertising, the advertising intensity is greater under free-to-air television. We also show that free-to-air television tends to provide less differentiated content whereas pay-tv stations always maximally differentiate their content. In addition, we compare the welfare properties of the two different scheme
Thomas Morse TM-23
No full text1/2 rear left hand side view of the Thomas Morse TM-23, a civilian aircraft, on the ground.https://corescholar.libraries.wright.edu/special_ms223_photographs/1715/thumbnail.jp
Synthesis optimization and charge carrier transfer mechanism in LiLuSiO<sub>4</sub>:Ce, Tm storage phosphor
No full textLiLuSiO4:Ce and LiLuSiO4:Ce, Tm show very efficient charge carrier storage properties upon beta irradiation after samples have received treatment in vacuum. They outperform the commercial storage phosphor BaFBr(I):Eu2+ in many aspects. The influence of the synthesis conditions, Ce and Tm concentration, nonstoichiometry and codoping with Ca, Hf, Al and Ge are reported. Based on the results of the synthesis optimization, thermoluminescence (TL) emission and TL excitation spectra a mechanism of charge carrier transfer, storage, and recombination during irradiation and thermal or optical readout is proposed.Accepted Author ManuscriptRST/Fundamental Aspects of Materials and EnergyRST/Luminescence Material
Assorted core air-clad fibre
No full textAn optical fibre containing a selection of,independently addressable air-clad cores with different dimensions is presented. The intrinsic properties of such an assorted core fibre are studied and potential applications are reviewed The physical dimensions required for guidance at various wavelengths are explored
Performance evaluation of mobile WiMAX with MIMO and relay extensions
No full textThe latest mobile WiMAX standard promises to deliver high data rates over extensive areas and to large user densities. More specifically, data rates are expected to exceed those of conventional cellular technologies. The IEEE 802.16e WiMAX standard enables the deployment of metropolitan area networks to mobile terminals in non-line-of-sight radio environments. Current concerns include leveraging high data rates, increasing area coverage, and competing with beyond 3G networks. Based on the IEEE 802.16e wirelessMAN-OFDMA (orthogonal frequency division multiple access) physical (PHY) layer air-interface, this paper presents a physical layer study of MIMO enabled mobile WiMAX in an urban environment. The radio channels are based on those developed in the European Union IST-WINNER project. Results are given in terms of system throughput and outage probability with and without relays for a range of SISO, MISO and MIMO architectures. Results show that satisfactory performance cannot be achieved in macrocells unless radio relays are used in combination with MIMO-STBC.The latest mobile WiMAX standard promises to deliver high data rates over extensive areas and to large user densities. More specifically, data rates are expected to exceed those of conventional cellular technologies. The IEEE 802.16e WiMAX standard enables the deployment of metropolitan area networks to mobile terminals in non-line-of-sight radio environments. Current concerns include leveraging high data rates, increasing area coverage, and competing with beyond 3G networks. Based on the IEEE 802.16e wirelessMAN-OFDMA (orthogonal frequency division multiple access) physical (PHY) layer air-interface, this paper presents a physical layer study of MIMO enabled mobile WiMAX in an urban environment. The radio channels are based on those developed in the European Union IST-WINNER project. Results are given in terms of system throughput and outage probability with and without relays for a range of SISO, MISO and MIMO architectures. Results show that satisfactory performance cannot be achieved in macrocells unless radio relays are used in combination with MIMO-STBC
A GIS approach to modelling traffic related air pollution
No full textThere is increased concern regarding the effect of traffic related pollution on public
heath. As the number of vehicles on the roads continues to rise, it is becoming
increasingly more important to identify areas where the population may be at a greater
risk to raised levels of pollution and areas where the implementation of policy to
control and monitor levels of pollution would be beneficial.
Traditionally, levels of air pollution have been established through dispersion modelling
or monitoring. However, for modelling traffic related pollution for large populations,
these methods have proved inappropriate.
Three new approaches have been developed to model traffic related air pollution and
are reported in this thesis. The approaches have been developed in a Geographical
Information System (GIS) and involve generating detailed maps of the pollution
surface from monitored data and information about the pollution sources. The new
methods are compared against the geostatistical technique kriging.
The first approach combines spatial interpolation from monitoring sites and dispersion
modelling, linking the dispersion model to the GIS, the second combines GIS
techniques for filtering data and spatial interpolation, and the third uses a combination
of GIS techniques for filtering and statistical techniques.
The three approaches are tested and validated by predicting levels of pollution at
monitoring sites not used to develop the models. It was found that the new
approaches provided more reliable estimates of pollution at unsampled locations than
kriging, with the last of these proving to be the most effective. The adjusted r2 values
for kriging, interpolation and dispersion, interpolation and filtering, and filtering and
statistics were found to be 0.44, 0.63, 0.67 and 0.82 respectively.
The approaches therefore have clear potential in the areas of air pollution management
and epidemiology, where the maps can be used to help identify locations where levels
of pollution exceed air quality standards, assess the relationship between air pollution
and health outcome and examine the risk of exposure to raised levels of pollution
Recommended from our members
A Low Cost, Quick Reaction TM Acquisition System Solution for Deployed Testing
No full textITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaDesign, development, fabrication, and deployment of an austere, deployable telemetry (TM) system, in only 3 1/2 weeks, will be discussed. This austere approach will be compared to a standard approach. TM candidate systems will be discussed along with exigencies and limitations (test geometry, link analysis, multiple test areas, schedule, cost, fabrication ...) that shaped their selection. Utilization of existing Radio Frequency (RF) systems in "unintended" applications will be discussed. System setup and BER testing with a simulated 'aircraft' will be presented, including observed multipath effects during testing, versus actual performance. Finally, benefits and test efficiencies garnered by having vehicle TM, real- time TM acquisition, processing and display, while deployed to a test area with no range instrumentation, will be presented.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection
Study of Tm valence state in CaSi2O2N2 and phosphor-enabled PowerWindow application
No full textPowerWindow is a luminescent solar concentrator which employs a Tm2+-doped material to strongly absorb sunlight and produce a sharp emission in the near-infrared spectrum for energy-harvesting purposes. The absence of self-absorption and the large spectral overlap with the solar spectrum make it an attractive addition to current building-integrated photovoltaics development. Such Tm2+-doped materials have so far been limited to halides that are susceptible to decomposition when exposed to air, which compromises its stability and limits the application. The solutions to functionalize the characteristic Tm2+ photoluminescence properties are two-fold: by an alternative inorganic host (CaSi2O2N2) that is insensitive to moisture, or by using a protective barrier (silicone) that protects halides against decomposition upon exposure to air. The proposed alternative phosphor CaSi2O2N2:Tm is synthesized by solid-state reaction and its luminescent property is examined. The Tm dopant is found to exist in trivalent state (Tm3+) and no luminescence of Tm2+ is found in the material. Besides Tm2O3, different starting powders with other oxidation states (TmI2 and Tm metal powder) were tested to reduce Tm3+ ion to Tm2+ but no change has been observed. It is concluded that the high-lying Tm2+ 4f electronic ground state in CaSi2O2N2 is susceptible to oxidization by losing electrons to its conduction band and therefore unlikely to be stabilized with this synthesis method. The protective barrier approach applied to the NaCl:Tm2+ phosphors was realized by a polydiphenylsiloxane silicone encapsulant. The precursors and the phosphors are cured together in a lamination scheme between two pieces of glass. From the optical properties derived from its absorption and transmission spectra, it is concluded that the Tm2+ valence state of NaCl:Tm2+ is stable in the polymer with no sign of Tm3+ formation at all. While its production process and the relative amount of phosphor still need to be further optimized, a proof-of concept has been attained
- …
