2,408 research outputs found
Energy-producing ability of bacteria under oxidative stress
Nitrosative stress is caused by reactive nitrogen species (RNS) and is toxic to most organisms. RNS are generated by the immune system to combat infectious microbes and are known to impede O2-dependent energy production. The goal of this study was to elucidate alternative adenosine triphosphate (ATP)-forming pathways that enable the model bacterium Pseudomonas fluorescens to survive a nitrosative challenge in a fumarate medium. Fumarate was metabolized by fumarase C (FUM C), a RNS-resistant enzyme and fumarate reductase (FRD). The enhanced activities of pyruvate phosphate dikinase (PPDK), adenylated kinase (AK) and nucleoside diphosphate kinase (NDPK) provided an effective route to ATP production by substrate-level phosphorylation (SLP), a process that does not require O2. The metabolic networks utilized to neutralize nitrosative stress reveal potential target against RNS-tolerant bacteria and a route to the conversion of fumarate into succinate, a value-added product.Master of Science (M.Sc.) in Biolog
Flow Secure Message in Parity Matrix
The goal of security is confidential ,integrity and availability to decrypt the messages.In recent years,many researchers has said about how to secure high-value data on hard disk.proposed system explains about the high grade cryptosystem one which even an attacker possessing both a copy of your encryption engine and knowledge of your operation.
DOI: 10.17762/ijritcc2321-8169.15014
The resource theory of informational nonequilibrium in thermodynamics
We review recent work on the foundations of thermodynamics in the light of
quantum information theory. We adopt a resource-theoretic perspective, wherein
thermodynamics is formulated as a theory of what agents can achieve under a
particular restriction, namely, that the only state preparations and
transformations that they can implement for free are those that are thermal at
some fixed temperature. States that are out of thermal equilibrium are the
resources. We consider the special case of this theory wherein all systems have
trivial Hamiltonians (that is, all of their energy levels are degenerate). In
this case, the only free operations are those that add noise to the system (or
implement a reversible evolution) and the only nonequilibrium states are states
of informational nonequilibrium, that is, states that deviate from the
maximally mixed state. The degree of this deviation we call the state's
nonuniformity; it is the resource of interest here, the fuel that is consumed,
for instance, in an erasure operation. We consider the different types of state
conversion: exact and approximate, single-shot and asymptotic, catalytic and
noncatalytic. In each case, we present the necessary and sufficient conditions
for the conversion to be possible for any pair of states, emphasizing a
geometrical representation of the conditions in terms of Lorenz curves. We also
review the problem of quantifying the nonuniformity of a state, in particular
through the use of generalized entropies. Quantum state conversion problems in
this resource theory can be shown to be always reducible to their classical
counterparts, so that there are no inherently quantum-mechanical features
arising in such problems. This body of work also demonstrates that the standard
formulation of the second law of thermodynamics is inadequate as a criterion
for deciding whether or not a given state transition is possible.Comment: 51 pages, 9 figures, Revised Versio
Campus Interactive Chatbot for Students
Chatbots are the Bots where user gets the information which he needed from the Bot in natural language without getting help from the third party or a person. In this paper Campus interactive chatbot uses an artificial Intelligence that analyses the user query and understand the user message later provide a response based on the user query. Students should individually need to go to college if he need any information like courses offered by the college, college timings, admission process, etc. from help desk. This process is timing consuming and requires manpower to provide information to the students. Hence, Interactive chatbots can developed to provide information to the use
Nonlinear Dynamics of Heat-Exchanger Tubes Under Crossflow: A Time-Delay Approach
Fluid-conveying heat-exchanger tubes in nuclear power plants are subjected to a secondary cross-flow to facilitate heat exchange. Beyond a critical value of the secondary flow velocity, the tube loses stability and vibrates with large amplitude. The equation governing the dynamics of a heat-exchanger tube is a delay differential equation (DDE). In all the earlier studies, only the stability boundaries in the parametric space of mass-damping parameter and reduced flow-velocity were reported. In this work using Galerkin approximations, the spectrum (characteristic roots) of the DDE is also obtained. The rightmost characteristic root, whose real part represents the damping in the heat-exchanger tube is included in the stability chart for the first time. The highest damping is found to be present in localized areas of the stability charts, which are close to the stability boundaries. These charts can be used to determine the optimal cross-flow velocities for operating the system for achieving maximum damping. Next, the interaction between the tube and the surrounding cladding at the baffle-plate makes it vital to determine the optimal design parameters for the baffle plates. The linear stability of a heat-exchanger tube modeled as a single-span Euler-Bernoulli cantilever beam subjected to cross-flow is studied with two parameters: (i) varying stiffness of the baffle-cladding at the free end and (ii) varying flow velocity. The partial delay differential equation governing the dynamics of the continuous system is discretized to a set of finite, nonlinear DDEs through a Galerkin method in which a single mode is considered. Unstable regions in the parametric space of cladding stiffness and flow velocity are identified, along with the magnitude of damping in the stable region. This information can be used to determine the design cladding stiffness to achieve maximum damping at a known operational flow velocity. Moreover, the system is found to lose stability by Hopf bifurcation and the method of multiple scales is used to analyze its post-instability behavior. Stable and unstable limit cycles are observed for different values of the linear component of the dimensionless cladding stiffness. An optimal range for the linear cladding stiffness is recommended where tube vibrations would either diminish to zero or assume a relatively low amplitude associated with a stable limit cycle. Furthermore, heat-exchanger tubes undergo thermal expansion, and are consequently subject to thermal loads acting along the axial direction, apart from design-induced external tensile loads. Nonlinear vibrations of a heat-exchanger tube modeled as a simply-supported EulerBernoulli beam under axial load and cross-flow have been studied. The fixed points (zero and buckled equilibria) of the nonlinear DDE are found, and their linear stability is analyzed. The stability of the DDE is investigated in the parametric space of fluid velocity and axial load. The method of multiple scales is used to study the post-instability behavior for both zero and buckled equilibria. Multiple limit-cycles coexist in the parametric space, which has implications on the fatigue life calculations of the heat-exchanger tubes
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