1,543 research outputs found
Size-Dependent Bruggeman Approach for Dielectric-Magnetic Composite Materials
Expressions arising from the Bruggeman approach for the homogenization of
dielectric-magnetic composite materials, without ignoring the sizes of the
spherical particles, are presented. These expressions exhibit the proper limit
behavior. The incorporation of size dependence is directly responsible for the
emergence of dielectric-magnetic coupling in the estimated relative
permittivity and permeability of the homogenized composite material.Comment: 4 pages, accepted for publication in AEU
Helical structures from an isotropic homopolymer model
We present Monte Carlo simulation results for square-well homopolymers at a
series of bond lengths. Although the model contains only isotropic pairwise
interactions, under appropriate conditions this system shows spontaneous chiral
symmetry breaking, where the chain exists in either a left- or a right-handed
helical structure. We investigate how this behavior depends upon the ratio
between bond length and monomer radius.Comment: 10 pages, 3 figures, accepted for publication by Physical Review
Letter
Rabindranath Tagore: In the Age of Globalization Sarkar Rimi and Ghosh Aritra
Abstract The some and substance of Rabindranath's vie
Kuiper Binary Object Formation
It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to
theoretical expectations. Their creation presents problems to most current
models. However, the inclusion of a third body (for example, one of the outer
planets) may provide the conditions necessary for the formation of these
objects. The presence of a third massive body not only helps to clear the
primordial Kuiper Belt but can also result in long lived binary Kuiper belt
objects. The gravitational interaction between the KBOs and the third body
causes one of four effects; scattering into the Oort cloud, collisions with the
growing protoplanets, formation of binary pairs, or creation of a single Kuiper
belt object. Additionally, the initial location of the progenitors of the
Kuiper belt objects also has a significant effect on binary formation
Dust Grain Orbital Behavior Around Ceres
Many asteroids show indications they have undergone impacts with meteoroid
particles having radii between 0.01 m and 1 m. During such impacts, small dust
grains will be ejected at the impact site. The possibility of these dust grains
(with radii greater than 2.2x10-6 m) forming a halo around a spherical asteroid
(such as Ceres) is investigated using standard numerical integration
techniques. The orbital elements, positions, and velocities are determined for
particles with varying radii taking into account both the influence of gravity,
radiation pressure, and the interplanetary magnetic field (for charged
particles). Under the influence of these forces it is found that dust grains
(under the appropriate conditions) can be injected into orbits with lifetimes
in excess of one year. The lifetime of the orbits is shown to be highly
dependent on the location of the ejection point as well as the angle between
the surface normal and the ejection path. It is also shown that only particles
ejected within 10 degrees relative to the surface tangential survive more than
a few hours and that the longest-lived particles originate along a line
perpendicular to the Ceres-Sun line.Comment: 8 pages, Presented at COSPAR '0
A decision support system for water quality issues in the Manzanares River (Madrid, Spain)
The Manzanares River, located in Madrid (Spain), is the main water supplier of a highly populated region,
and it also receives wastewater from the same area. The effluents of eight Waste Water Treatment Plants
(WWTPs) downstream of the river, which represent 90% of the flow in the middle and lower parts of the
river, are the primary sources of water pollution. Although the situation has improved slightly in the last two
years, the water in the river is highly polluted, making it uninhabitable for aquatic life. Water quality
modelling is typically used to assess the effect of treatment improvements in water bodies. In this work, the
GESCAL module of the Aquatool Decision Support System Shell was used to simulate water quality in the
Manzanares River. GESCAL is appropriate for modelling in an integrated way water quality for whole water
resources systems, including reservoirs and rivers. A model was built that simulates conductivity,
phosphorous, carbonaceous organic matter, dissolved oxygen, organic nitrogen, ammonia, and nitrates.
The period from October 2006 to September 2008 was selected for calibration due to the many treatment
modifications that occurred during this time. An earlier and longer period, from October 2000 to September
2006, was used for validation. In addition, a daily model was used to analyse the robustness of the GESCAL
model. Once the GESCAL model was validated, different scenarios were considered and simulated. First,
different combinations of nutrient elimination among the different WWTPs were simulated, leading to the
conclusion that investments have to focus on three of the proposed WWTPs. Moreover, these treatments will
not be sufficient to maintain fish habitat conditions at all times. Additional measures, such as the increment
of the flow in the river or oxygen injection, were simulated. Incrementing the flow of the Manzanares River
has been shown to be an efficient means of increasing water quality, but this implies an increment in the risk
of water scarcity situations in the Madrid water supply system.
© 2010 Elsevier B.V. All rights reserved.This work has been supported by the Spanish Ministry of Science and Innovation through the project Consolider-Ingenio 2010 CSD2009-00065.Paredes Arquiola, J.; Andreu Álvarez, J.; Solera Solera, A. (2010). A decision support system for water quality issues in the Manzanares River (Madrid, Spain). Science of the Total Environment. 408:2576-2589. https://doi.org/10.1016/j.scitotenv.2010.02.037S2576258940
Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry
During an initial field survey in 2012, we observed an unexpected asymmetry of dissolved oxygen distribution between the western and eastern side in northern Lake Iseo. Motivated by this apparent anomaly, we conducted a detailed field investigation, and we used a physical model of the northern part of the lake to understand the in- fluences that might affect the distribution of material in the northern section of the lake. These investigations sug- gested that the Earth's rotation has significant influence on the inflow of the lake's two main tributaries. In order to further crosscheck the validity of these results, we conducted a careful analysis at a synoptic scale using images acquired during thermally unstratified periods by Landsat-8 and Sentinel-2 satellites. We retrieved and post- processed a large set of images, providing conclusive evidence of the role exerted by the Earth's rotation on pol- lutant transport in Lake Iseo and of the greater environmental vulnerability of the north-west shore of this lake, where important settlements are located. Our study confirms the necessity for three-dimensional hydrodynamic models including Coriolis effect in order to effectively predict local impacts of inflows on nearshore water quality of medium-sized elongated lakes of similar scale to Lake Iseo
Rethinking of patient-centered medicine in Japan
xxviii,136 hlm, 21 c
Long-term phenomenological model of phosphorus and oxygen for stratified lakes
A budget model is developed to predict the long-term response of a lake to changes in its phosphorus loading. This model computes total phosphorus and hypolimnetic oxygen concentrations, taking sediment-water interactions into account.The lake is treated as two segments: the water and a surface sediment layer. A total phosphorus budget for the water accounts for inputs due to external loading and recycle from the sediments. It reflects losses due to flushing and settling. The sediment layer gains total phosphorus by settling and loses total phosphorus by recycle and burial. The recycle from the sediments to the water is dependent on the levels of sediment total phosphorus and hypolimnetic oxygen. Hypolimnetic oxygen concentration is estimated with a semi-empirical model.The model is applied to Shagawa Lake. An analysis is performed to demonstrate how its predictions replicate in-lake changes not possible with simpler phosphorus budget models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29315/1/0000380.pd
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