351,008 research outputs found
Uniqueness and stability of time and space-dependent conductivity in a hyperbolic cylindrical domain
This paper is devoted to the reconstruction of the time and space-dependent
coefficient in an infinite cylindrical hyperbolic domain. Using a local
Carleman estimate we prove the uniqueness and a H\"older stability in the
determining of the conductivity by a single measurement on the lateral
boundary. Our numerical examples show good reconstruction of the location and
contrast of the conductivity function in three dimensions.Comment: arXiv admin note: text overlap with arXiv:1501.0138
Joint Dynamic Radio Resource Allocation and Mobility Load Balancing in 3GPP LTE Multi-Cell Network
Load imbalance, together with inefficient utilization of system resource, constitute major factors responsible for poor overall performance in Long Term Evolution (LTE) network. In this paper, a novel scheme of joint dynamic resource allocation and load balancing is proposed to achieve a balanced performance improvement in 3rd Generation Partnership Project (3GPP) LTE Self-Organizing Networks (SON). The new method which aims at maximizing network resource efficiency subject to inter-cell interference and intra-cell resource constraints is implemented in two steps. In the first step, an efficient resource allocation, including user scheduling and power assignment, is conducted in a distributed manner to serve as many users in the whole network as possible. In the second step, based on the resource allocation scheme, the optimization objective namely network resource efficiency can be calculated and load balancing is implemented by switching the user that can maximize the objective function. Lagrange Multipliers method and heuristic algorithm are used to resolve the formulated optimization problem. Simulation results show that our algorithm achieves better performance in terms of user throughput, fairness, load balancing index and unsatisfied user number compared with the traditional approach which takes resource allocation and load balancing into account, respectively
The Behaviour of Finely Ground Bottom Ash in Portland Cement
The aim of this project was to assess the effects of finely ground MSWI bottom ash in Portland cement. Mortar mixes were prepared with 10% and 40% replacement of cement by ground IBA and then tested with regards to their material composition and engineering behaviour. IBA was found not to be inert, but showed some degree of reactivity. Replacement of cement with IBA was found to have no detrimental effects at low concentrations. This was not the case for 40% replacement, where cement replacement greatly affected strength, creep and drying shrinkage
Swift Observations of X-ray supernovae
We present a result of X-ray supernovae (SNe) survey using the Swift
satellite public archive. An automatic searching program was designed to search
X-ray SNe among all of the Swift archival observations between November 2004
and February 2011. Using the C++ program, 24 X-ray detectable supernovae have
been found in the archive and 3 of them were newly-discovered in X-rays which
are SN 1986L, SN 2003lx, and SN 2007od. In addition, SN 2003lx is a Type Ia
supernova which may be the second X-ray detectable Type Ia after SN 2005ke
(Immler et al. 2006). Calibrated data of luminous type Ib/c supernovae was
consistent to the X-ray emission model done by Chevalier & Fransson (1994).
Statistics about the luminosities and hardness ratio have been done to purpose
of getting the X-ray emission features of the X-ray supernovae. The results
from this work help investigating the X-ray evolution of SNe and developing
similar X-ray SNe surveys in various X-rays missions
QED Penguin Contributions To Isospin Splittings of Heavy-Light Quark Systems
Recent experiments show that the isospin-violating mass splitting of the B
mesons is very small, but the best fits with a QCD sum rule analysis give a
splitting of at least 1.0 MeV. The isospin-violating mass splittings of the
charmed mesons, on the other hand, are in agreement with experiment. In this
letter we show that the inclusion of 2 kind QED penguin diagrams can
account for this discrepancy within the errors in the QCD sum rule method.Comment: 9 pages, latex, 2 figure
"Hidden” degassing from streams: estimation of the CO2 release from the thermal springs of Sperchios Basin, Greece
Areas located at plate boundaries are characterized by the presence of seismic, volcanic, and geothermal activity, as well as ore deposition. Such processes are enhanced by the circulation of hydrothermal fluids in the crust transporting volatiles from either the deep crust or the mantle to the surface. Intense geodynamic activity is also taking place in Greece giving rise to: (i) the highest seismicity in Europe, (ii) the presence of an active volcanic arc and numerous areas of anomalously high geothermal gradient, and (iii) a widespread occurrence of thermal springs. Elevated heat flow values are concentrated in Sperchios basin, an area characterised by a system of deeply rooted extensional faults and quaternary volcanic activity. This regime favoured the formation of hydrothermal systems, the surface expression of which are thermal springs with intense bubbling of CO2-rich gases. Flux measurements in the bubbling pools were made with the floating chamber method. The highest bubbling CO2 output is found in Thermopyles and Psoroneria (1 and 2 t/d, respectively). The outgoing channels of these springs have an elevated flow (>250 l/s) of gas-charged water (>15 mmol/l of CO2). Although no bubbling is noticed along the stream, the CO2 content decreases by an order of magnitude after few hundreds of metres, indicating an intense degassing from the water. Taking into account the water flow and the amount of CO2 lost to the atmosphere, the CO2 output of the outgoing channels is quantified in >10 t/d for Thermopyles and 9 t/d for Psoroneria. An estimation is also made at Ypati, Kamena Vourla, Koniavitis and Edipsos, where the mean values reach 1 t/d of CO2 for each spring. The obtained values are always higher respect to the estimated outputs from visible bubbling, suggesting that most of the degassing is “hidden”. Furthermore, the loss of CO2 from the water determines a shift in dissolved carbonate species as demonstrated by the pH increase along the channel that leads eventually to an oversaturation in carbonate minerals and therefore travertine deposition. To sum up, the total CO2 output of the study area is estimated at 30 t/d, with the major contribution deriving from the degassing along the outflow channels of the thermal springs. Such output is comparable to that of the single active volcanic systems along the South Aegean Volcanic Arc (Sousaki, Methana, Milos, Santorini, Kos and Nisyros) and highlights the importance of “hidden” degassing along CO2-oversaturated streams
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