401 research outputs found
Fast numerical evaluation of time-derivative nonadiabatic couplings for mixed quantum-classical methods
We have developed a numerical differentiation scheme which eliminates
evaluation of overlap determinants in calculating the time-derivative
non-adiabatic couplings (TDNACs). Evaluation of these determinants was the
bottleneck in previous implementations of mixed quantum-classical methods using
numerical differentiation of electronic wave functions in the
Slater-determinant representation. The central idea of our approach is, first,
to reduce the analytic time derivatives of Slater determinants to time
derivatives of molecular orbitals, and then to apply a finite-difference
formula. Benchmark calculations prove the efficiency of the proposed scheme
showing impressive several-order-of-magnitude speedups of the TDNAC calculation
step for midsize molecules.Comment: 4 page
Development and validation of UV spectrophotometric method for simultaneous estimation of propranolol hydrochloride and rosuvastatin calcium in bulk drug and pharmaceutical dosage form
A new, simple and sensitive UV spectrophotometric method has been developed for simultaneous quantitative determination of propranolol hydrochloride and rosuvastatin calcium in bulk and pharmaceutical dosage form. This is achieved by simultaneous equation (Vierodts method) and absorbance ratio (Q- point) method. Propranolol hydrochloride and rosuvastatin calcium exhibits maximum absorbance at 289 nm and 243 nm respectively in methanol as solvent. Beers law was found to be obeyed in the concentration range 2-40 g/ml for propranolol hydrochloride and 2-42 g/ml or rosuvastatin calcium. Method were validated for linearity, accuracy, precision, LOD, LOQ as per ICH guidelines
Empirical Correlations of Longwall Subsidence Data for the Illinois Coal Basin
Subsidence, mining and site data has been collected over a number of longwall panels in the Illinois Basin. Using this data, empirical correlations are attempted to various subsidence parameters, including maximum vertical and horizontal displacement, subsidence slope and curvature and horizontal strain. Also, the corresponding locations of these various subsidence characteristics are correlated to the associated site conditions. An extensive list of definitions are provided for the various subsidence parameters utilized in the paper
Application of Supply Chain Tools In Power Plant- A Case of Rayalaseema Thermal Power Plant
Inventories are considered to be one of the important weapons of supply chain to improve the efficiency of any manufacturing unit. Continuous availability of inventories are the prime requirement for uninterrupted working .To effectively manage inventory levels, it is essential to consider the appropriate reorder points as well as the optimized ordering quantity. The proposed system uses the Genetic algorithm to find the optimized ordering quantity at proper reorder point , by considering the power plant live data as a practical case study. The proposed approach is implemented in Matlab platform version 7.10 Key words. Inventories, supply chain, Genetic algorithm, Reorder point, ordering quantity, manufacturing unit, power plant, raw materials
Estimation of sediment acoustic properties from horizontal array data
Oil companies conduct geophysical survey in different parts of the world. While the analysis conducted by them is directed towards determining the presence of oil in the deeper layers of the sediment, information on the shallower sediment layers that the data contains is generally ignored. In this paper we investigate the possibility of estimating the sediment properties from such data. The inversion is performed using both linear and non-linear methods. The performances of these methods are compared based on the correlation between the fields predicted by the models and the measured field
Effects of Substrate Heating and Wettability on Evaporation Dynamics and Deposition Patterns for a Sessile Water Droplet Containing Colloidal Particles
Effects of substrate temperature, substrate wettability and particles
concentration are experimentally investigated for evaporation of a sessile
water droplet containing colloidal particles. Time-varying droplet shapes and
temperature of the liquid-gas interface are measured using high-speed
visualization and infrared thermography, respectively. The motion of the
particles inside the evaporating droplet is qualitatively visualized by an
optical microscope and profile of final particle deposit is measured by an
optical profilometer. On a non-heated hydrophilic substrate, a ring-like
deposit forms after the evaporation, as reported extensively in the literature;
while on a heated hydrophilic substrate, a thinner ring with an inner deposit
is reported in the present work. The latter is attributed to Marangoni
convection and recorded motion of the particles as well as measured temperature
gradient across the liquid-gas interface confirms this hypothesis. The thinning
of the ring scales with the substrate temperature and is reasoned to stronger
Marangoni convection at larger substrate temperature. In case of a non-heated
hydrophobic substrate, an inner deposit forms due to very early depinning of
the contact line. On the other hand, in case of a heated hydrophobic substrate,
the substrate heating as well as larger particle concentration helps in the
pinning of the contact line, which results in a thin ring with an inner
deposit. We propose a regime map for predicting three types of deposits namely,
ring, thin ring with inner deposit and inner deposit - for varying substrate
temperature, substrate wettability and particles concentration. A first-order
model corroborates the liquid-gas interface temperature measurements and
variation in the measured ring profile with the substrate temperature
A comparative study of the learning styles among 1st, 2nd and final year MBBS students
Background: Learning style is the way students begin to focus, internalize and remember new and difficult information. Identifying the learning styles of medical students will enable the faculty to use appropriate T/L method to increase the grasping ability of their subject/ learning. Purpose of the study was to assess and compare the learning styles of 1st, 2nd and final MBBS students by using VARK questionnaire.Methods: This was an observational, cross-sectional study based on the questionnaire, conducted by the department of Pharmacology at Basaveshwara Medical College and Hospital, Chitradurga. The VARK learning styles assessment questionnaire was administered to 1st (96 students), 2nd (60 students) and Final year (49 students). The students were categorized as auditory, kinaesthetic, visual learner or read/write depending on the predominant option they chose. Independent sample 't' test was used to compare the mean scores between the two groups using the software SPSS v22.Results: 40% of students had unimodal and 60% had multimodal learning style. Final year MBBS students had higher percentage of multimodal learning style (73%). The most preferred style of learning among all the medical students was kinesthetic (6.6), followed by aural (5.5), visual (4.0) and read/write (3.5). There was significant difference between the learning styles of 1st and Final year MBBS students in Visual (p=0.01) and Read /Write (p= 0.008).Conclusions: Knowing that students have different learning styles and kinesthetic being the most preferred mode of learning will help medical faculty to develop teaching/learning strategies for better outcomes
Processing of ilmenite (FeOTiO2) for value added products
Beach Placer Ilmenite is an important source for production of titanium metal, titania slag and pigment
grade titanium dioxide. Besides, these well known applications for which Ilmenite is mined and
processed, there are other emerging processes that are being tried for obtaining highvalue products.
Synthesis of Ilmenite based materials for varistor applications and direct electrochemical reduction of
Ilmenite to produce ferrotitanium are two such attempts being discussed in this work.
In this paper, recent efforts undertaken to study the electrical and magnetic characteristics are
discussed. Ilmenite, FeTiO 3 , is one of the mixed-valence transition metalbearing minerals, inwhich Fe
can be in two different oxidation states, Fe
2+
and Fe
3+
.. Similarly, Ti can be in Ti
3+
and Ti
4+
.Ilmenite is
inherently suitable for making Varistors, which are devices, used for limiting the transient voltage
surges in a circuit. Varistors produced from Ilmenite can withstand harsh environments seen in nuclear
reactors and outerspace. Electrochemical reduction of Ilmenite can be used to prepare ferrotitanium
directly without any reductant. The process essentially involves removal of oxygen from the mineral
through electrolytic action using calcium chloride as electrolyte and graphite as anode. At a
temperature of 950°C, it is shown to be possible that all the oxygen can be removed from the Ilmenite
sample, which passes through the electrolyte, to form CO/CO 2 at the anode. The process has
immense potential for cost effective production of titanium metal as well. Results of the above
developmental works are presented in this paper
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