Metal-Oxide Frameworks-based Cobalt Oxides as Efficient Electrocatalysts

Green energy production via cost-effective ways is one of the main requirements in current days. Hydrogen as a green fuel source is very attractive for a sustainable future as hydrogen is considered a zero-carbon emission fuel. Hydrogen can be produced via many routes. Among many approaches, hydrogen generation via water splitting is one of the greenest ways to get green fuel. In most cases, hydrogen production via water splitting requires efficient electrocatalysts to reduce the overpotential (extra cost) of this process. Platinum and rareearth-based materials are considered efficient electrocatalysts, however, their high cost is one of the limiting factors. process. In this work, metal oxide framework-based cobalt oxides were synthesized and used as efficient electrocatalysts for water splitting applications. The nanostructured MOF-based cobalt oxides were prepared using a facile method that can be easily adapted for commercial applications. The samples were hoghly porous with a high surface area which acted as active sites for electrocatalytic activities. The materials\u27 properties were tuned by calcining the samples at various temperatures. These materials showed low overpotential in the range of 75 to 137 mV to achieve a current density of 10 mA/cm2 for hydrogen production. Depending on the growth conditions, these materials required an overpotential in the range of 370 to 440 mV for oxygen production. These materials showed stable performance for up to 1,000 cycles of cyclic voltammetric studies suggesting possible commercial applications in fuel cell technology

Massive photons: an infrared regularization scheme for lattice QCD+QED

Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions.Comment: 6 pages, 4 figures, 2 tables; significant revisions to abstract and main text; revised presentation of results for clarity (results unchanged); acknowledgements updated; matches published versio

Information erasure without an energy cost

Landauer argued that the process of erasing the information stored in a memory device incurs an energy cost in the form of a minimum amount of mechanical work. We find, however, that this energy cost can be reduced to zero by paying a cost in angular momentum or any other conserved quantity. Erasing the memory of Maxwell's demon in this way implies that work can be extracted from a single thermal reservoir at a cost of angular momentum and an increase in total entropy. The implications of this for the second law of thermodynamics are assessed.Comment: 8 pages with 1 figure. Final published versio

Optimum design for BB84 quantum key distribution in tree-type passive optical networks

We show that there is a tradeoff between the useful key distribution bit rate and the total length of deployed fiber in tree-type passive optical networks for BB84 quantum key distribution applications. A two stage splitting architecture where one splitting is carried in the central office and a second in the outside plant and figure of merit to account for the tradeoff are proposed. We find that there is an optimum solution for the splitting ratios of both stages in the case of Photon Number Splitting (PNS) attacks and Decoy State transmission. We then analyze the effects of the different relevant physical parameters of the PON on the optimum solution.Comment: Published in the Journal of the Optical Society of America

Semi-hierarchical based motion estimation algorithm for the dirac video encoder

Having fast and efficient motion estimation is crucial in today’s advance video compression technique since it determines the compression efficiency and the complexity of a video encoder. In this paper, a method which we call semi-hierarchical motion estimation is proposed for the Dirac video encoder. By considering the fully hierarchical motion estimation only for a certain type of inter frame encoding, complexity of the motion estimation can be greatly reduced while maintaining the desirable accuracy. The experimental results show that the proposed algorithm gives two to three times reduction in terms of the number of SAD calculation compared with existing motion estimation algorithm of Dirac for the same motion estimation accuracy, compression efficiency and PSNR performance. Moreover, depending upon the complexity of the test sequence, the proposed algorithm has the ability to increase or decrease the search range in order to maintain the accuracy of the motion estimation to a certain level