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Modulation of Excited-State Proton-Transfer Dynamics inside the Nanocavity of Microheterogeneous Systems: Microenvironment-Sensitive Forster Energy Transfer to Riboflavin
No full textThe excited-state proton-transfer efficiency of a tetraarylpyrene derivative, 1,3,6,8-tetrakis(4-hydroxy-2,6-dimethylphenyl)pyrene (TDMPP), was investigated thoroughly in the presence of various surfactant assemblies, such as micelles and vesicles. The confined microheterogeneous environments can significantly retard the extent of the excited-state proton-transfer process, resulting in a distinguishable optical signal compared to that in the bulk medium. Physical characteristics of the surfactant assemblies, such as order, interfacial hydration, and surface charge, influence the proton transfer process and allow multiparametric sensing. A higher degree of interfacial hydration facilitates the proton-transfer process, while the positively charged head groups of the surfactants specifically stabilize the anionic form of the probe (TDMPP-O*). Furthermore, Forster energy transfer from the probe to riboflavin was studied in a phospholipid membrane, wherein the relative ratio of the neutral versus anionic forms (TDMPP-OH/TDMPP-O*) was found to influence the extent of energy transfer. Overall, we demonstrate how an ultrafast photophysical process, that is, the excited-state proton transfer, can be influenced by the microenvironment
Fixed Length Differential Encoding for Real-Time Status Updates
No full textWe consider the status updates of a physical process over an unreliable channel. In this setting, one may not be able to reliably transmit the current state at all times. Instead, one is interested in the timeliness of the accurately received information. This is a setting for several cyber-physical system applications that require real-time monitoring and control. In this paper, we study periodic data transmission schemes at a single source which exploit the temporal correlation in the source messages. When the source has no feedback, it can periodically send the actual information, interspersed with differential messages. On the availability of receiver's feedback at the source, it can decide to send either the differential or the actual information at each transmission opportunity. For a fixed length coding, we show that the differential encoding improves the timeliness performance only if the receiver's feedback is available
Photon-Free Degradation of Dyes by Ge/GeO2 Porous Microstructures
No full textSeveral industries use dyes as coloring agents and release untreated effluents in the form of wastewater that has created panic due to the environmental issue. Considerable efforts have been extended to develop photocatalysts for the degradation of these dyes. Here, we report the photon-free degradation of various cationic and anionic dyes for the first time by Ge/GeO2 porous microstructures. The degradation efficiency and time are found to be dependent on the catalyst amount, and it is possible to achieve, similar to 100% degradation without any external stimuli. Our experimental results indicate that Ge donates electrons either directly to dye molecules or to dissolved oxygen (O-2) molecules and creates superoxide species without any extra energy source that bleaches or degrades the dyes. However, it is essential to have a continuous supply of electrons from Ge core to sustain the degradation process
Search for a W boson decaying to a vector-like quark and a top or bottom quark in the all-jets final state
No full textA search for a heavy W resonance decaying to one B or T vector-like quark and a top or bottom quark, respectively, is presented. The search uses proton-proton collision data collected in 2016 with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1) at 13 TeV. Both decay channels result in a final state with a top quark, a Higgs boson, and a b quark, each produced with significant energy. The all-hadronic decays of both the Higgs boson and the top quark are considered. The final-state jets, some of which correspond to merged decay products of a boosted top quark and a Higgs boson, are selected using jet substructure techniques, which help to suppress standard model backgrounds. A W boson signal would appear as a narrow peak in the invariant mass distribution of these jets. No significant deviation in data with respect to the standard model background predictions is observed. Cross section upper limits on W boson production in the top quark, Higgs boson, and b quark decay mode are set as a function of the W mass, for several vector-like quark mass hypotheses. These are the first limits for W boson production in this decay channel, and cover a range of 0.01 to 0.43 pb in the W mass range between 1.5 and 4.0 TeV
Meromorphic quadratic differentials and measured foliations on a Riemann surface
No full textWe describe the space of measured foliations induced on a compact Riemann surface by meromorphic quadratic differentials. We prove that any such foliation is realized by a unique such differential q if we prescribe, in addition, the principal parts of root q at the poles. This generalizes a theorem of Hubbard and Masur for holomorphic quadratic differentials. The proof analyzes infinite-energy harmonic maps from the Riemann surface to R-trees of infinite co-diameter, with prescribed behavior at the poles
In-situ preparation of nanostructured alpha-MnO2/polypyrrole hybrid composite electrode materials for high performance supercapacitor
No full textIn-situ manganese oxide/polypyrrole (MnO2/Ppy) nanocomposites have been prepared by a simple co-precipitation method using pyrrole and aqueous KMnO4 solution under ambient conditions. The effect of annealing temperature on the structure, morphology, specific surface area, and electrochemical capacitance properties have been studied. The as-prepared MnO2/Ppy nanocomposite has large BET surface area of 232 m(2) g(-1) with a pore size of 6.6 nm. The high discharge capacitance of as-prepared MnO2/Ppy nanocomposite is 290 F g(-1), when the electrode is cycled in a aqueous solution of 0.1 M Ca(NO3)(2)center dot 4H(2)O at a current density of 0.5 A g(-1). The capacitance retention after 3,000 cycles is about 90% of the initial capacitance at a current density of 1 A g(-1). A simple preparation method adopted to synthesize MnO2/Ppy nanocomposite is advantageous and the specific capacitance is high with good cycling stability. (C) 2019 Elsevier B.V. All rights reserved
Coastal reservoir strategy to enhance India's freshwater storage by impounding river flood waters: a detailed overview
No full textThis paper revisits the water resource scenario in India and presents the adequacy of the coastal reservoir concept to address water scarcity by impounding excess river flood waters. Although there has been no significant change in India's rainfall pattern in the last 100 years, there is a spatial non-uniformity in the rainfall events that occur which makes it difficult to pre-plan large-scale water storage at different locations. This study highlights the fact that there is enough water available but the deficiency is in storage. A large portion of freshwater from river systems, groundwater and wetlands drains into the sea due to insufficient storage facilities. Coastal reservoirs enable the storage of excess river flood waters near the coast for future use. This paper discusses current water supply solutions available in the country, and the efficacy of coastal reservoirs along with feasibility implications. The associated rewards and challenges are also discussed. The paper presents details of existing coastal reservoirs worldwide and recent feasibility studies envisaging coastal reservoirs in India
Robust Initial Satellite Orbit Determination method using a Modified Kalman Filter
No full textThe control segment in satellite navigation systems is responsible for estimating satellite orbit and clock bias which is required for a reliable Position, Navigation and Timing (PNT) user service. Initial orbit determination is a crucial step which accounts for all unknowns/anomalous parameters such as satellite orbit manoeuvres, on board and receiver clock frequency variations and environmental effects. It is vital that the estimates of the orbits and clock are insensitive to these factors. In this paper, an initial orbit determination method is presented using existing robust methodology for estimation of initial satellite position and its propagation using a variant of the Kalman Filter (KF) which allows the initial position determination process to be independent of satellite and receiver anomalies. The derivation of this KF variant is presented. Preliminary results obtained from simulated data are shown. The said method is checked for robustness by comparing results obtained for a given satellite position data set with that from the conventional Kalman Filter. The conventional KF exhibits divergence due to anomalies which are eliminated by the use of the method presented in this paper
A thermodynamically consistent peridynamics model for visco-plasticity and damage
No full textThis article presents a unified visco-plastic-damage model in the peridynamics set-up which may be applied across different regime of strain rates and temperatures. In the model, we introduce two internal variables, one describing plastic flow and other the damage in the material. Exploiting the idea of master balance, in addition to the conventional momentum balances, we postulate micro-force balances for both plastic flow and damage evolution in terms of additional peridynamic force states. The equations of motion are in the form of integro-differential equations and do not require continuity of field variables. Using the idea of energy equivalence and entropy equivalence, constitutive relations for the peridynamic force states are determined. The proposed peridynamic visco-plastic-damage model may be thought as a non-trivial extension of the recently developed peridynamic viscoplasticity model (Rahaman et al.,2017). The current scheme couples the visco-plasticity and damage in a thermo-dynamically consistent manner and provides temperature evolution which reflects contribution from both plasticity and damage. The efficacy of the model is demonstrated through simulations of the adiabatic shear band propagation as observed in Kalthoff-Winkler experiment and the shear plugging failure of Weldox 460 E steel plates along with the determination of the ballistic limit. (C) 2019 Elsevier B.V. All rights reserved