16 research outputs found
Estimation of greenhouse gas emissions from spontaneous combustion/fire of coal in opencast mines â Indian context
There are a significant number of uncontrolled coal mine fires (primarily due to spontaneous combustion of coal), which are currently burning all over the world. These spontaneous combustion sources emit greenhouse gases (GHGs). A critical review reveals that there are no standard measurement methods to estimate GHG emissions from mine fire/spontaneous combustion areas. The objective of this research paper was to estimate GHGs emissions from spontaneous combustion of coals in the Indian context. A sampling chamber (SC) method was successfully used to assess emissions at two locations of the Enna Opencast Project (OCP), Jharia Coalfield (JCF), for 3 months. The study reveals that measured cumulative average emission rate for CO2 varies from 75.02 to 286.03 gsâ1mâ1 and CH4 varies from 41.49 to 40.34 gsâ1mâ1 for low- and medium-temperature zones. The total GHG emissions predicted from this single fire affecting mines of JCF vary from 16.86 to 20.19 Mtyrâ
The SANTANA project
Smart antennas employing digital beamforming (DBF) at Ka-band frequencies will be key elements for the next generation of broadband satellite communication systems. This frequency band offers high bandwidth and therefore high data rate capability, whereas digital beamforming provides a high degree of system flexibility.
Within the SANTANA (Smart Antenna Terminal) project, key elements of advanced DBF satellite communication terminals at Ka-band frequencies have been developed. SANTANA is a joint project of IMST GmbH and TU Hamburg-Harburg with DLR Oberpfaffenhofen, EADS Astrium GmbH. Industrial support is provided by Lewicki Microelectronics GmbH, RHe Microsystems, and EPAK GmbH. The project is funded and supported by the German Space Agency (DLR) on behalf of the German Ministry of Economics and Technology (BMWi).
Within the SANTANA project framework of phase 1 (2001 - 2003) and phase 2 (2003 - 2007), a complete medium size DBF system has been realised. It consists of separate transmit (30 GHz) and receive (20 GHz) units with 64 antenna elements each. This DBF system has been successfully demonstrated by establishing bidirectional communication links to moving platforms (car and aircraft) equipped with a conventional transmit/receive unit. The aim of the current project phase 3 is the adaptation of the present technology towards large arrays, the verification of the terminal within a moving environment, and the further industrialisation of several building blocks.
The paper describes the whole system and reports the essential experimental results obtained during the field tests
Active Antenna Arrays at Ka-Band: Status and Outlook of the SANTANA Project
This paper gives an overview on different research activities on electronically steerable antennas at Ka-band within the framework of the SANTANA project. In addition, it gives an outlook on future objectives, namely the perspective of testing SANTANA technologies with the projected German research satellite âHeinrich Hertzâ
Impact of roadside tree lines on indoor concentrations of traffic-derived particulate matter
Exposure to airborne particulate pollution is associated with premature mortality and a range of inflammatory illnesses, linked to toxic components within the particulate matter (PM) assemblage. The effectiveness of trees in reducing urban PM10 concentrations is intensely debated. Modeling studies indicate PM10 reductions from as low as 1% to as high as âź60%. Empirical data, especially at the local scale, are rare. Here, we use conventional PM10 monitoring along with novel, inexpensive magnetic measurements of television screen swabs to measure changes in PM10 concentrations inside a row of roadside houses, after temporarily installing a curbside line of young birch trees. Independently, the two approaches identify >50% reductions in measured PM levels inside those houses screened by the temporary tree line. Electron microscopy analyses show that leafcaptured PM is concentrated in agglomerations around leaf hairs and within the leaf microtopography. Iron-rich, ultrafine, spherical particles, probably combustion-derived, are abundant, form a particular hazard to health, and likely contribute much of the measured magnetic remanences. Leaf magnetic measurements show that PM capture occurs on both the road-proximal and -distal sides of the trees. The efficacy of roadside trees for mitigation of PM health hazard might be seriously underestimated in some current atmospheric models