Linear Hamilton Jacobi Bellman Equations in High Dimensions

The Hamilton Jacobi Bellman Equation (HJB) provides the globally optimal solution to large classes of control problems. Unfortunately, this generality comes at a price, the calculation of such solutions is typically intractible for systems with more than moderate state space size due to the curse of dimensionality. This work combines recent results in the structure of the HJB, and its reduction to a linear Partial Differential Equation (PDE), with methods based on low rank tensor representations, known as a separated representations, to address the curse of dimensionality. The result is an algorithm to solve optimal control problems which scales linearly with the number of states in a system, and is applicable to systems that are nonlinear with stochastic forcing in finite-horizon, average cost, and first-exit settings. The method is demonstrated on inverted pendulum, VTOL aircraft, and quadcopter models, with system dimension two, six, and twelve respectively.Comment: 8 pages. Accepted to CDC 201

PHYTOCHEMICAL TO INTERACT WITH NLS BINDING SITE ON IMA3 TO INHIBIT IMPORTIN Α/Β1 MEDIATED NUCLEAR IMPORT OF SARS-COV-2 CARGO

Objective: Ivermectin is an FDA-approved, broad-spectrum anti-parasitic agent. It was originally identified as an inhibitor of interaction between the human 29 immunodeficiency virus-1 (HIV-1) integrase protein (IN) and the Importin (IMP) α/β1 30 heterodimers, which are responsible for IN nuclear import. Recent studies demonstrate that ivermectin is worthy of further consideration as a possible SARS-CoV-2 antiviral. Methods: We built the pathogen-host interactome and analyzed it using PHISTO. We compared Ivermectin and plant molecules for their interaction with Importin α3 (IMA3) using molecular docking studies. Results: A phytochemical ATRI001 with the lowest binding energy-7.290 Kcal/mol was found to be superior to Ivermectin with binding energy-4.946 Kcal/mol. Conclusion: ATRI001 may be a potential anti-SARS-CoV-2 agent; however, it requires clinical evaluation

Spin and energy correlations in the one dimensional spin 1/2 Heisenberg model

In this paper, we study the spin and energy dynamic correlations of the one dimensional spin 1/2 Heisenberg model, using mostly exact diagonalization numerical techniques. In particular, observing that the uniform spin and energy currents decay to finite values at long times, we argue for the absence of spin and energy diffusion in the easy plane anisotropic Heisenberg model.Comment: 10 pages, 3 figures, gzipped postscrip

DEVELOPMENT AND VALIDATION OF STABILITY-INDICATING HPTLC METHOD FOR DETERMINATION OF DOLASETRON MESYLATE

Objective: To develop and validate stability indicating HPTLC method for determination of Dolasetron mesylate.Methods: The chromatographic separation was performed on aluminium plates precoated with silica gel 60 F254 using Methanol: Choloroform: Ethyl acetate (7:2:1 v/v/v) as mobile phase followed by densitometric scanning at 280 nm.Results: The chromatographic condition gave a compact spot for Dolasetron mesylate at Rf value of 0.65±0.03. Stress testing was performed in accordance with international conference on harmonization (ICH) Q1A R2 guidelines. Method was validated as per ICH Q2 R1 guidelines. The calibration curve was found to be linear in the concentration range of 100-800 ng/band for Dolasetron mesylate. The limit of detection and quantification was found to2.24 ng/band and 6.79 ng/band, respectively.Conclusion: A new sensitive, simple, and stability indicating high performance thin layer chromatographic (HPTLC) method has been developed and validated for determination of Dolastron mesylate. The proposed method can be used for routine determination of Dolasetron mesylate stability.Â

Semiclassical spin liquid state of easy axis Kagome antiferromagnets

Motivated by recent experiments on Nd-langasite, we consider the effect of strong easy axis single-ion anisotropy $D$ on $S > 3/2$ spins interacting with antiferromagnetic exchange $J$ on the Kagome lattice. When $T \ll DS^2$, the collinear low energy states selected by the anisotropy map on to configurations of the classical Kagome lattice Ising antiferromagnet. However, the low temperature limit is quite different from the cooperative Ising paramagnet that obtains classically for $T \ll JS^2$. We find that sub-leading ${\mathcal O}(J^3S/D^2)$ multi-spin interactions arising from the transverse quantum dynamics result in a crossover from an intermediate temperature classical cooperative Ising paramagnet to a semiclassical spin liquid with distinct short-ranged correlations for $T \ll J^3S/D^2$.Comment: 4 pages, 3 eps figure

Comment on "Spin Transport properties of the quantum one-dimensional non-linear sigma model"

In a recent preprint (cond-mat/9905415), Fujimoto has used the Bethe ansatz to compute the finite temperature, zero frequency Drude weight of spin transport in the quantum O(3) non-linear sigma model in a magnetic field $H \neq 0$. We show here that, contrary to his claims, the results are in accord with earlier semiclassical results (Sachdev and Damle, cond-mat/9610115). We also comment on his 1/N expansion, and show that it does not properly describe the long-time correlations.Comment: 4 page

Griffiths phase in the thermal quantum Hall effect

Two dimensional disordered superconductors with broken spin-rotation and time-reversal invariance, e.g. with p_x+ip_y pairing, can exhibit plateaus in the thermal Hall coefficient (the thermal quantum Hall effect). Our numerical simulations show that the Hall insulating regions of the phase diagram can support a sub-phase where the quasiparticle density of states is divergent at zero energy, \rho(E)\sim |E|^{1/z-1}, with a non-universal exponent $z>1$, due to the effects of rare configurations of disorder (``Griffiths phase'').Comment: 4+ pages, 5 figure

Investigation of Alternate Valvetrain Strategies for Implementation of Diesel Engine Cylinder Deactivation

Cylinder deactivation is a technique in multi-cylinder engines where the airflow and fuel injection are deactivated to a few of the total number of the cylinders such that the power demand is met by increasing fuel consumption in the remaining active cylinders. Diesel engine cylinder deactivation has been demonstrated to have fuel savings of 3.4% over heavy duty federal test procedure and approximately 4 – 35% fuel benefit is predicted over the port drayage cycle, while maintaining higher aftertreatment temperatures. Deactivation of cylinders can result in a decay in in-cylinder pressure via heat loss and blowby to the crankcase, which can lead to oil transport from the crankcase to the cylinder. Oil accumulation in the cylinders can deplete the lubricating oil faster and lead to misfiring or poor combustion when these cylinders are reactivated. This study involves the evaluation of different valvetrain strategies to address the issue of oil accumulation in the deactivated cylinders, while maintaining the benefits provided by cylinder deactivation. A commercial engine simulation software GT-Power, experimentally validated with experimental data, will be used in this study for simulation of the novel valvetrain strategies. The study will determine the effects and benefits of various intake and exhaust valve opening by varying the valve lifts, valve closing and opening timings for each of the two intake and two exhaust valves. The simulation results have shown that the valve strategies implemented have helped to maintain the incylinder pressures at around the atmospheric pressure in addition to maintaining the benefits of cylinder deactivation

Fabrication of low cost and versatile internal field pulsed nuclear magnetic resonance spectrometer to study the magnetic materials

We have built a low cost and versatile pulsed internal field nuclear magnetic resonance (IFNMR) spectrometer and used it to study ferromagnetic materials. Initially optimization of the instrument has been tested with nuclear quadrupole resonance (NQR) active nuclei. Ferromagnetic materials like bulk iron, bulk cobalt and carbon coated cobalt nanopowder have been used as the testing materials for our spectrometer. Preliminary results obtained from the present spectrometer have been compared with the earlier reports and are in good agreement. The specifications and performance standard of the instrument match quite well with standard instruments elsewhere in the world which is testified with the observation of NMR echo signals in the above mentioned materials confirming the quality of the spectrometer. Additionally NMR signals from the grain boundaries are observed in Co@C nanomaterials which prove the sensitivity of the spectrometer

Spin-3/2 random quantum antiferromagnetic chains

We use a modified perturbative renormalization group approach to study the random quantum antiferromagnetic spin-3/2 chain. We find that in the case of rectangular distributions there is a quantum Griffiths phase and we obtain the dynamical critical exponent $Z$ as a function of disorder. Only in the case of extreme disorder, characterized by a power law distribution of exchange couplings, we find evidence that a random singlet phase could be reached. We discuss the differences between our results and those obtained by other approaches.Comment: 4 page