INHIBITIVE BEHAVIOUR OF GREEN INHIBITOR IN POTABLE WATER DISTRIBUTION SYSTEM

The inhibition effect of amino trimethylene phosphonic acid (ATMP) and zinc ions on the corrosion of carbon steel in potable water distribution system was investigated. The corrosion inhibiting action was studied through weight loss, potentiodynamic polarization and AC impedance spectroscopy techniques. The possibilities of formation of protective complex was examined using UV – visible spectroscopy. The investigations revealed that zinc acts as an excellent synergist in corrosion inhibition. UV – visible spectral study indicates that there will be a possibility of formation of complexes of ATMP and Zn2+ with carbon steel iron. Polarization studies indicate that the new binary system is a mixed inhibitor. Result of the impedance studies shows that a protective film is formed on the metal surface in presence of the inhibitor formulation

A Rational Approach to Cryptographic Protocols

This work initiates an analysis of several cryptographic protocols from a rational point of view using a game-theoretical approach, which allows us to represent not only the protocols but also possible misbehaviours of parties. Concretely, several concepts of two-person games and of two-party cryptographic protocols are here combined in order to model the latters as the formers. One of the main advantages of analysing a cryptographic protocol in the game-theory setting is the possibility of describing improved and stronger cryptographic solutions because possible adversarial behaviours may be taken into account directly. With those tools, protocols can be studied in a malicious model in order to find equilibrium conditions that make possible to protect honest parties against all possible strategies of adversaries

Variation of electrical resistivity with high pressure in Ge-Te-Sn glasses: A composition dependent study

The variation of normalized electrical resistivity in the system of glasses Ge_{15}Te_{85-x}Sn_{x} with (1 ≤ x ≤ 5) has been studied as a function of high pressure for pressures up to 9.5 GPa. It is found that with the increase in pressure, the resistivity decreases initially and shows an abrupt fall at a particular pressure, indicating the phase transition from semiconductor to near metallic at these pressures, which lie in the range 1.5-2.5 GPa, and then continues being metallic up to 9.5 GPa. This transition pressure is seen to decrease with the increase in the percentage content of tin due to increasing metallicity of tin. The semiconductor to near metallic transition is exactly reversible and may have its origin in a reduction of the band gap due to high pressure

Experimental demonstration of quantum illumination using polarization-entangled photon pairs and CHSH value as measure

Entangled light sources for illuminating objects offers advantages over conventional illumination methods by enhancing the detection sensitivity of a reflecting object. The crux of the quantum advantage lies in way we can practically leverage quantum correlations to isolate the background noise and detect the low reflectivity object. In this work we experimentally demonstrated the advantages of using polarization-entangled photon pairs for quantum illumination and show that the quantum correlation measure using CHSH value is robust against background noise and losses. We also show that the residual of quantum correlations help in identifying the object of reflectivity, $\eta$ as low as 0.05 and when signal-to-noise ratio is as low as 0.003 for $\eta=0.7$, surpassing the earlier demonstrated results. Robustness of correlation measure with photon attenuation in atmospheric condition is analysed to show the practical feasibility of the real time application.Comment: 9 Pages, 8 Figure

Fair and optimistic quantum contract signing

We present a fair and optimistic quantum contract signing protocol between two clients that requires no communication with the third trusted party during the exchange phase. We discuss its fairness and show that it is possible to design such a protocol for which the probability of a dishonest client to cheat becomes negligible, and scales as N^{-1/2}, where N is the number of messages exchanged between the clients. Our protocol is not based on the exchange of signed messages: its fairness is based on the laws of quantum mechanics. Thus, it is abuse-free, and the clients do not have to generate new keys for each message during the Exchange phase. We discuss a real-life scenario when the measurement errors and qubit state corruption due to noisy channels occur and argue that for real, good enough measurement apparatus and transmission channels, our protocol would still be fair. Our protocol could be implemented by today's technology, as it requires in essence the same type of apparatus as the one needed for BB84 cryptographic protocol. Finally, we briefly discuss two alternative versions of the protocol, one that uses only two states (based on B92 protocol) and the other that uses entangled pairs, and show that it is possible to generalize our protocol to an arbitrary number of clients.Comment: 11 pages, 2 figure

Experimental realization of universal quantum gates and six-qubit state using photonic quantum walk

Controlled quantum walk forms the basis for various quantum algorithm and quantum simulation schemes. Though theoretical proposals are also available to realize universal quantum computation using quantum walks, no experimental demonstration of universal set of gates has been reported. Here we report the experimental realize of universal set of quantum gates using photonic quantum walk. Taking cue from the discrete-time quantum walk formalism, we encode multiple qubits using polarization and paths degree of freedom for photon and demonstrate realization of universal set of gates with 100\% success probability and high fidelity, as characterised by quantum state tomography. For a 3-qubit system we encode first qubit with $H$ and $V-$polarization of photon and path information for the second and third qubit, closely resembling a Mach-Zehnder interference setup. To generate a 6-qubit system and demonstrate 6-qubit GHZ state, entangled photon pairs are used as source to two 3-qubit systems. We also provide insights into the mapping of quantum circuits to quantum walk operations on photons and way to resourcefully scale. This work marks a significant progress towards using photonic quantum walk for quantum computing. It also provides a framework for photonic quantum computing using lesser number of photons in combination with path degree of freedom to increase the success rate of multi-qubit gate operations.Comment: 13 pages, 8 figures. Tomography figures for all gate operations are available upon reques

Quality-of-Service Routing Using Path and Power Aware Techniques in Mobile Ad Hoc Networks

Mobile ad hoc network (MANET) is a collection of wireless mobile hosts dynamically forming a temporary network without the aid of any existing established infrastructure. Quality of service (QoS) is a set of service requirements that needs to be met by the network while transporting a packet stream from a source to its destination. QoS support MANETs is a challenging task due to the dynamic topology and limited resources. The main objective of this paper is to enhance the QoS routing for MANET using temporally ordered routing algorithm (TORA) with self-healing and optimized routing techniques (SHORT). SHORT improves routing optimality by monitoring routing paths continuously and redirecting the path whenever a shortcut path is available. In this paper, the performance comparison of TORA and TORA with SHORT has been analyzed using network simulator for various parameters. TORA with SHORT enhances performance of TORA in terms of throughput, packet loss, end-to-end delay, and energy