Intramolecular vibrational energy redistribution as state space diffusion: Classical-quantum correspondence

We study the intramolecular vibrational energy redistribution (IVR) dynamics of an effective spectroscopic Hamiltonian describing the four coupled high frequency modes of CDBrClF. The IVR dynamics ensuing from nearly isoenergetic zeroth-order states, an edge (overtone) and an interior (combination) state, is studied from a state space diffusion perspective. A wavelet based time-frequency analysis reveals an inhomogeneous phase space due to the trapping of classical trajectories. Consequently the interior state has a smaller effective IVR dimension as compared to the edge state.Comment: 5 pages, 3 figure

Thermo-mechanical forming of Al-Mg-Si Sheet

In warm forming of aluminum sheet, the temperature and strain rates vary considerably. In simulations, the material\ud model must be capable to predict stresses within this wide range. Here, the physically based Nes model is used to describe\ud the behavior of AA6061-T4 sheet material under warm forming conditions. A significant change of earing behavior is\ud found between room temperature and 250 ºC. Crystal plasticity calculations showed a reasonable correspondence of\ud changing r-values if extra slip systems are considered at high temperatures. Satisfactory results are obtained for simulation\ud of tensile tests and cylindrical deep drawing

Understanding highly excited states via parametric variations

Highly excited vibrational states of an isolated molecule encode the vibrational energy flow pathways in the molecule. Recent studies have had spectacular success in understanding the nature of the excited states mainly due to the extensive studies of the classical phase space structures and their bifurcations. Such detailed classical-quantum correspondence studies are presently limited to two or quasi two dimensional systems. One of the main reasons for such a constraint has to do with the problem of visualization of relevant objects like surface of sections and Wigner or Husimi distributions associated with an eigenstate. This neccesiates various alternative techniques which are more algebraic than geometric in nature. In this work we introduce one such method based on parametric variation of the eigenvalues of a Hamiltonian. It is shown that the level velocities are correlated with the phase space nature of the corresponding eigenstates. A semiclassical expression for the level velocities of a single resonance Hamiltonian is derived which provides theoretical support for the correlation. We use the level velocities to dynamically assign the highly excited states of a model spectroscopic Hamiltonian in the mixed phase space regime. The effect of bifurcations on the level velocities is briefly discussed using a recently proposed spectroscopic Hamiltonian for the HCP molecule.Comment: 12 pages, 9 figures, submitted to J. Chem. Phy

Analyzing intramolecular vibrational energy redistribution via the overlap intensity-level velocity correlator

Numerous experimental and theoretical studies have established that intramolecular vibrational energy redistribution (IVR) in isolated molecules has a heirarchical tier structure. The tier structure implies strong correlations between the energy level motions of a quantum system and its intensity-weighted spectrum. A measure, which explicitly accounts for this correaltion, was first introduced by one of us as a sensitive probe of phase space localization. It correlates eigenlevel velocities with the overlap intensities between the eigenstates and some localized state of interest. A semiclassical theory for the correlation is developed for systems that are classically integrable and complements earlier work focusing exclusively on the chaotic case. Application to a model two dimensional effective spectroscopic Hamiltonian shows that the correlation measure can provide information about the terms in the molecular Hamiltonian which play an important role in an energy range of interest and the character of the dynamics. Moreover, the correlation function is capable of highlighting relevant phase space structures including the local resonance features associated with a specific bright state. In addition to being ideally suited for multidimensional systems with a large density of states, the measure can also be used to gain insights into the phase space transport and localization. It is argued that the overlap intensity-level velocity correlation function provides a novel way of studying vibrational energy redistribution in isolated molecules. The correlation function is ideally suited to analyzing the parametric spectra of molecules in external fields.Comment: 16 pages, 13 figures (low resolution

Assessment of drug-drug interactions in the prescription of elderly patients on cardiovascular drugs

Background: Cardiovascular disease is one of the major causes of mortality and morbidity in a developing country like India. These patient’s prescription contains multiple drugs to reduce the mortality and morbidity and they also contain drugs for treatment of co morbidities leading to polypharmacy. The main objective of the study was to identify the pattern of drug- drug interaction (DDI) in patients on cardiovascular drugs with various co existing morbidities.Methods: This study was conducted in the Department of General Medicine of a tertiary care center. Prescription of 200 patients were analysed for demographic details like gender, age, comorbidities and drugs prescribed. DDI were assessed using Micromedex software.Results: In this study, conducted on the prescription of 200 elderly patients, 13 (66%) prescription had 408 DDI, of which 158 (39%) were major, 246 (60%) were moderate and 1 (0.02%) was contraindicated and 3 (0.007%) were minor.Conclusions: It can be concluded from the present study that the risk of DDI increases with the increase in number of drugs in the prescription and there is increase in number of drugs in the prescription with the increase in number of co morbidities. The antiplatelet and anticoagulant group of drugs were responsible for majority of DDI, followed by antihypertensives and hypoglycaemic agents. Most of these DDI could be avoided with slight modification in the dosage regimen based on the pharmacokinetics and pharmacodynamics of the drug

On Discrete Wrapped Cauchy Model

Modeling angular data throws many challenges in practical situations. Good number of circular / semicircular models are developed for modeling continuous circular / angular data. Scant attention was paid in analysis of discrete angular data, in particular, construction of discrete angular models for fitting angular data is not touched so far. Hence an attempt is made to develop method for constructing Discrete l - axial models and study their population characteristics.Keywords: China insurance industry, Foreign fund, Challenge DOI: 10.7176/MTM/9-4-02 Publication date: April 30th 2019

Performance evaluation of a manually operated paddy drum seeder - a cost saving technology for paddy cultivation

 A study was conducted at farmer field to evaluate performance of mechanized paddy cultivation (T1), mechanized paddy cultivation with incorporation of Dhaincha before direct sowing of paddy seed (T2) and the traditional farmer practice (T3).  Consecutive three years of data were obtained for analysis and different crop growth parameters were measured like panicle length, number of tillers, grain yield etc. for each treatment.  It was found that the average grain yield for three years in different treatments T1 and T2 was enhanced by 10% and 14% respectively when compared with farmer practice.  Average cost of cultivation was reduced by 25% in treatment T2 where green manuring crop (Dhaincha) was grown and incorporated in soil with indigenous plough before paddy seeding.  Study also revealed that due to mechanized cultivation practices, the crop was ready to harvest eight to ten days early than farmer’s practices.  The experiment well proved to raise the socio-economic status of the farmers by changing their strategy towards mechanized organic paddy cultivation.   Keywords: drum seeder, mechanization, green manuring crop, growth parameters

Preparation of transversely isotropic test specimen of natural FRP composite - an innovative approach-II

Fiber Reinforced Plastic (FRP) composites can be broadly classified as synthetic and natural, based on the type of fibers incorporated. Abundantly available natural fibers like toddy palm, sisal, jute and banana are attracting the attention of researchers due to ever increasing demand for lighter, stronger and eco-friendly materials from the industry. However, natural fibers are limited in length, not so uniform in size and behave differently in different atmospheric conditions. Added to this, the inherent tendency of natural fibers to twist and curl in dry conditions poses many problems to researchers while preparing test specimens. Researchers in general and academicians in particular are handicapped by non-availability of relevant literature on fabrication techniques to prepare natural FRP composite test specimens close to their analytical models. Present paper addresses typical problems faced by researchers during preparation of unidirectional continuous fiber reinforced composite test specimen ensuring transversely isotropic nature. Using simple hand tools coupled with a few precautions taken as described herein, prospective researchers can condition natural fibers and prepare composite specimen to suit their requirements.&nbsp