On the predictions for diffusion-driven evaporation of sessile droplets with interface cooling

The diffusion-driven evaporation of sessile droplets from planar surfaces is influenced by cooling at the air-liquid interface. Here, corrections to the available models for predicting the evaporation process are presented. The mass conservation for diffusion-driven evaporation is resolved by considering the effect of interface cooling on the change in density of saturated vapour along the liquid-vapour interface of sessile droplets. Corrections to the predictions for the spatial distribution of vapour density around a sessile droplet and the evaporative flux of vapour at the interface are obtained. The classical models are recovered from the new predictions if interface cooling is negligible. Comparison between the new and classical predictions for the local surface evaporative flux is obtained using the literature data. Our analysis shows a significant effect of interface cooling which should be considered in predicting diffusion-driven evaporation of sessile droplets on planar surfaces

Chiral spinors and gauge fields in noncommutative curved space-time

The fundamental concepts of Riemannian geometry, such as differential forms, vielbein, metric, connection, torsion and curvature, are generalized in the context of non-commutative geometry. This allows us to construct the Einstein-Hilbert-Cartan terms, in addition to the bosonic and fermionic ones in the Lagrangian of an action functional on non-commutative spaces. As an example, and also as a prelude to the Standard Model that includes gravitational interactions, we present a model of chiral spinor fields on a curved two-sheeted space-time with two distinct abelian gauge fields. In this model, the full spectrum of the generalized metric consists of pairs of tensor, vector and scalar fields. They are coupled to the chiral fermions and the gauge fields leading to possible parity violation effects triggered by gravity.Comment: 50 pages LaTeX, minor corrections and references adde

Economic analysis of climate change adaptation strategies in selected coastal areas in Indonesia, Philippines and Vietnam

This report is an account of a cross-country study that covered Vietnam, Indonesia and the Philippines. Covering four sites (one each in Indonesia and Vietnam) and two sites in the Philippines, the study documented the impacts of three climate hazards affecting coastal communities, namely typhoon/flooding, coastal erosion and saltwater intrusion. It also analyzed planned adaptation options, which communities and local governments can implement, as well as autonomous responses of households to protect and insure themselves from these hazards. It employed a variety of techniques, ranging from participatory based approaches such as community hazard mapping and Focus Group Discussions (FGDs) to regression techniques, to analyze the impact of climate change and the behavior of affected communities and households

Collective edge modes in fractional quantum Hall systems

Over the past few years one of us (Murthy) in collaboration with R. Shankar has developed an extended Hamiltonian formalism capable of describing the ground state and low energy excitations in the fractional quantum Hall regime. The Hamiltonian, expressed in terms of Composite Fermion operators, incorporates all the nonperturbative features of the fractional Hall regime, so that conventional many-body approximations such as Hartree-Fock and time-dependent Hartree-Fock are applicable. We apply this formalism to develop a microscopic theory of the collective edge modes in fractional quantum Hall regime. We present the results for edge mode dispersions at principal filling factors $\nu=1/3,1/5$ and $\nu=2/5$ for systems with unreconstructed edges. The primary advantage of the method is that one works in the thermodynamic limit right from the beginning, thus avoiding the finite-size effects which ultimately limit exact diagonalization studies.Comment: 12 pages, 9 figures, See cond-mat/0303359 for related result

Effect of energy source, salt concentration and loading force on colloidal interactions between Acidithiobacillus ferrooxidans cells and mineral surfaces

The surface appendages and extracellular polymeric substances of cells play an important role in the bacterial adhesion process. In this work, colloidal forces and nanomechanical properties of Acidithiobacillus ferrooxidans (A. f) interacted with silicon wafer and pyrite (FeS2) surfaces in solutions of varying salt concentrations were quantitatively examined using the bacterial probe technique with atomic force microscopy. A. f cells were cultured with either ferrous sulfate or elemental sulfur as key energy sources. Our results show that A. f cells grown with ferrous ion and elemental sulfur exhibit distinctive retraction force vs separation distance curves with stair-step and saw tooth shapes, respectively. During the approach of bacterial probes to the substrate surfaces, surface appendages and biopolymers of cells are sequentially compressed. The conformations of surface appendages and biopolymers are significantly influenced by the salt concentrations. (c) 2015 Elsevier B.V. All rights reserved

Energy Consumption of Wireless Network Access Points

2nd International Conference on Green Communications and Networking, GreeNets 2012; Gandia; Spain; 25 October 2012 through 26 October 2012The development of low cost technology based on IEEE 802.11 standard permits to build telecommunication networks at low cost, allowing providing Internet access in rural areas in developing countries. The lack of access to the electrical grid is a problem when the network is being developed in rural areas, so that wireless access points should operate using solar panels and batteries. Many cases can be found where the energy consumption becomes a key point in wireless network design. In this paper we present a comparative study of the energy consumption of several wireless network access points. We will compare the energy consumption of different brands and models, for several operation scenarios and operating modes. Obtained results allow us to achieve the objective of this article, that is, promote the development of wireless communication networks energetically efficient.Andrade Morelli, S.; Ruiz Sanchez, E.; Granell Romero, E.; Lloret, J. (2013). Energy Consumption of Wireless Network Access Points. Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST. 113:81-91. doi:10.1007/978-3-642-37977-2_8S8191113Khoa Nguyen, K., Jaumard, B.: Routing Engine Architecture for Next Generation Routers: Evolutional Trends. Network Protocols and Algorithms 1(1), 62–85 (2009)IEEE Std 802.11: IEEE Standard for Information technology -Telecommunications and information exchange between systems -Local and metropolitan area networks - Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. Institute of Electrical and Electronics Engineers, New York, USA, pp.1–1184 (2007)Lloret, J., Garcia, M., Bri, D., Sendra, S.: A Wireless Sensor Network Deployment for Rural and Forest Fire Detection and Verification. Sensors 9(11), 8722–8747 (2009)Tapia, A., Maitland, C., Stone, M.: Making IT work for Municipalities: Building municipal wireless networks. Government Information Quarterly 23(3), 359–380 (2006)van Drunen, R., Koolhaas, J., Schuurmans, H., Vijn, M.: Building a Wireless Community Network in the Netherland. In: USENIX 2003 / Freenix Annual Technical Conference Proceedings, San Antonio, Texas, USA, June 9-14, pp. 219–230 (2003)Powell, A., Shade, L.R.: Going Wi-Fi in Canada: Municipal and Community Initiatives. Canadian Research Alliance for Community Innovation and Networking (2005)Sendra, S., Fernández, P.A., Quilez, M.A., Lloret, J.: Study and Performance of Interior Gateway IP routing Protocols. Network Protocols and Algorithms 2(4), 88–117 (2010)Galperin, H.: Wireless Networks and Rural Development: Opportunities for Latin America. Information Technologies and International Development 2(3), 47–56 (2005)Segal, M.: Improving lifetime of wireless sensor networks. Network Protocols and Algorithms 1(2), 48–60 (2009)Momani, A.A.E., Yassein, M.B., Darwish, O., Manaseer, S., Mardini, W.: Intelligent Paging Backoff Algorithm for IEEE 802.11 MAC Protocol. Network Protocols and Algorithms 4(2), 108–123 (2012)Mohsin, A.H., Bakar, K.A., Adekiigbe, A., Ghafoor, K.Z.: A Survey of Energy-aware Routing protocols in Mobile Ad-hoc Networks: Trends and Challenges. Network Protocols and Algorithms 4(2), 82–107 (2012)Feeney, L.M., Nilsson, M.: Investigating the Energy Consumption of a Wireless Network Interface in an Ad Hoc Networking Environment. In: Proceedings of the Twentieth Annual Joint Conference of the IEEE Computer and Communications Societies, INFOCOM 2001, Anchorage, Alaska, April 22-26, vol. 3, pp. 1548–1557. IEEE (2001)Barbancho, J., León, C., Molina, F.J., Barbancho, A.: Using artificial intelligence in routing schemes for wireless networks. Computer Communications 30(14-15), 2802–2811 (2007)Tao, C., Yang, Y., Honggang, Z., Haesik, K., Horneman, K.: Network energy saving technologies for green wireless access networks. IEEE Wireless Communications 18(5), 30–38 (2011)Sendra, S., Lloret, J., Garcia, M., Toledo, J.F.: Power saving and energy optimization techniques for Wireless Sensor Networks. Journal of Communications 6(6), 439–459 (2011

Current-Induced Torques in Magnetic Metals: Beyond Spin Transfer

Current-induced torques on ferromagnetic nanoparticles and on domain walls in ferromagnetic nanowires are normally understood in terms of transfer of conserved spin angular momentum between spin-polarized currents and the magnetic condensate. In a series of recent articles we have discussed a microscopic picture of current-induced torques in which they are viewed as following from exchange fields produced by the misaligned spins of current carrying quasiparticles. This picture has the advantage that it can be applied to systems in which spin is not approximately conserved. More importantly, this point of view makes it clear that current-induced torques can also act on the order parameter of an antiferromagnetic metal, even though this quantity is not related to total spin. In this informal and intentionally provocative review we explain this picture and discuss its application to antiferromagnets.Comment: 5 figures, to appear in Journal of Magnetism and

Edge reconstructions in fractional quantum Hall systems

Two dimensional electron systems exhibiting the fractional quantum Hall effects are characterized by a quantized Hall conductance and a dissipationless bulk. The transport in these systems occurs only at the edges where gapless excitations are present. We present a {\it microscopic} calculation of the edge states in the fractional quantum Hall systems at various filling factors using the extended Hamiltonian theory of the fractional quantum Hall effect. We find that at $\nu=1/3$ the quantum Hall edge undergoes a reconstruction as the background potential softens, whereas quantum Hall edges at higher filling factors, such as $\nu=2/5, 3/7$, are robust against reconstruction. We present the results for the dependence of the edge states on various system parameters such as temperature, functional form and range of electron-electron interactions, and the confining potential. Our results have implications for the tunneling experiments into the edge of a fractional quantum Hall system.Comment: 11 pages, 9 figures; minor typos corrected; added 2 reference

Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor