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Wyszukujesz frazę "Singh, S.R." wg kryterium: Autor


Tytuł:
Ultrasonic Attenuation in Dielectric Crystals
Autorzy:
Kor, S. K.
Singh, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/1891964.pdf
Data publikacji:
1991-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.Dc
62.65.+K
Opis:
Ultrasonic attenuation and non-linearity parameters have been evaluated for dielectric crystals RbCl, RbBr and RbI in a wide temperature range. Basic physical parameters, nearest neighbour distance and hardness parameters of the substance and Coulomb and Born-Mayer potentials have been used to obtain ultrasonic attenuation due to phonon-viscosity mechanism along (100) direction of propagation for longitudinal and shear waves. Results are as expected and it has been concluded that ultrasonic attenuation is a fundamental property of the substance.
Źródło:
Acta Physica Polonica A; 1991, 80, 6; 805-810
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonic Attenuation in Alloys
Autorzy:
Kor, S. K.
Singh, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/1929339.pdf
Data publikacji:
1993-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.Dc
62.65.+k
Opis:
Ultrasonic attenuation was evaluated in metallic alloys, Ni$\text{}_{x}$Cu$\text{}_{1-x}$ (x = 1.00, 0.70, 0.60, 0.45 and 0) due to phonon-phonon (p-p) interaction and thermoelastic loss in a wide temperature region along ⟨110⟩ crystallographic direction for longitudinal and shear waves. Ultrasonic Grüneisen parameters, nonlinearity constants and ultrasonic attenuation due to p-p interaction and thermoelastic loss were determined from 50 K to 500 K using the Born-Mayer and electrostatic potentials. The results were compared with available experimental results.
Źródło:
Acta Physica Polonica A; 1993, 83, 6; 751-758
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of van Hove Singularity on T$\text{}_{c}$ in Rb doped C$\text{}_{60}$
Autorzy:
Agrawal, B. K.
Agrawal, S.
Yadav, P. S.
Srivastava, P.
Srivastava, R.
Singh, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035748.pdf
Data publikacji:
2003-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Jb
74.62.Fj
74.70.Wz
Opis:
In the present study we investigate the role of van Hove singularity on the optimization of T$\text{}_{c}$ in Rb doped fullerenes C$\text{}_{60}$ Rb$\text{}_{3}$. A first principles self-consistent full potential linear muffin-tin orbital method using density functional theory in local density approximation was employed. The doped Rb atoms are of two types occupying the tetrahedral and interstitial positions in the fcc lattice. The added Rb atoms fill the t$\text{}_{1u}$ band of the undoped fullerenes C$\text{}_{60}$ up to half which makes C$\text{}_{60}$Rb$\text{}_{3}$ conducting. Saddle points leading to van Hove singularities are observed in the neighbourhood of the symmetry point L. The shifting of the van Hove singularity with the volume of the lattice is investigated. We observe a saddle point just at the Fermi level for a lattice constant of 14.435Å. The highest value of T$\text{}_{c}$ should thus be observed at the above lattice constant. This result is in excellent agreement with the observed high value of T$\text{}_{c}$ measured in C$\text{}_{60}$Rb$\text{}_{3}$ for a lattice constant of 14.435Å.
Źródło:
Acta Physica Polonica A; 2003, 103, 5; 477-482
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient soil solarization for weed control in the rain-fed upland rice ecosystem
Autorzy:
Khan, A.R.
Srivastava, R.C.
Ghorai, A.K.
Singh, S.R.
Powiązania:
https://bibliotekanauki.pl/articles/25142.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
environment
soil
ground water
weed competition
crop yield
herbicide
solarization
ecosystem
rainfed upland
weed control
toxic residue
rice
Źródło:
International Agrophysics; 2003, 17, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A diverse snake fauna from the early Eocene of Vastan Lignite Mine, Gujarat, India
Autorzy:
Rage, J -C
Folie, A.
Rana, R.S.
Singh, H.
Rose, K.D.
Smith, T.
Powiązania:
https://bibliotekanauki.pl/articles/22685.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Cambay Formation
Vastan Lignite Mine
Gujarat
fossil snake
Early Eocene
paleontology
Caenophidia
India
Serpentes
snake fauna
Opis:
The early Eocene (Ypresian) Cambay Formation of Vastan Lignite Mine in Gujarat, western India, has produced a diverse assemblage of snakes including at least ten species that belong to the Madtsoiidae, Palaeophiidae (Palaeophis and Pterosphenus), Boidae, and several Caenophidia. Within the latter taxon, the Colubroidea are represented by Russellophis crassus sp. nov. (Russellophiidae) and by Procerophis sahnii gen. et sp. nov. Thaumastophis missiaeni gen. et sp. nov. is a caenophidian of uncertain family assignment. At least two other forms probably represent new genera and species, but they are not named; both appear to be related to the Caenophidia. The number of taxa that represent the Colubroidea or at least the Caenophidia, i.e., advanced snakes, is astonishing for the Eocene. This is consistent with the view that Asia played an important part in the early history of these taxa. The fossils come from marine and continental levels; however, no significant difference is evident between faunas from these levels. The fauna from Vastan Mine includes highly aquatic, amphibious, and terrestrial snakes. All are found in the continental levels, including the aquatic palaeophiids, whereas the marine beds yielded only two taxa. Vastan Mine is only the second locality in which the palaeophiids Palaeophis and Pterosphenus co−occur. The composition of the fauna from Vastan is on the whole similar to that of the early Eocene of Europe; however, comparisons with early Eocene faunas of other continents are not possible because they are poorly known or unknown.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An ailuravine rodent from the lower Eocene Cambay Formation at Vastan, western India, and its palaeobiogeographic implications
Autorzy:
Rana, R S
Kumar, K.
Escarguel, G.
Sahni, A.
Rose, K.D.
Smith, T.
Singh, H.
Singh, L.
Powiązania:
https://bibliotekanauki.pl/articles/23190.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ischyromyidae
Cambay Formation
paleontology
Euromys inexpectatus
Euromys cardosoi
Rodentia
Eocene
India
Ailuravinae
Meldimys musak
Mammalia
ailuravine rodent
new species
Ailuravus michauxi
rodent
paleobiogeography
Western India
Opis:
A new ailuravine rodent, Meldimys musak sp. nov. (Mammalia: Rodentia, Ischyromyidae), is recorded from the lower Eocene lignites of western India. It is the oldest record of Rodentia from India. M. musak is more derived than the earliest Eocene ailuravine Euromys cardosoi from Portugal and more generalized than late early Eocene E. inexpectatus and Ailuravus michauxi from France. Its dental morphology closely corresponds to the middle early Eocene species M. louisi, which lived about 52 Ma in Western Europe. Meldimys was previously known only from Europe, and ailuravines were previously reported only from Europe and North America. Its occurrence in India allows the first direct correlation between the early Eocene land mammal horizons of Europe and India, and raises the possibility of a terrestrial faunal exchange between India and Eurasia close to the Palaeocene–Eocene transition.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature on Non-Destructive Wave Propagation in Uranium Monopnictides
Autorzy:
Singh, R.
Singh, M.
Chaurasia, S.
Powiązania:
https://bibliotekanauki.pl/articles/1808103.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.35.Cg
62.20.de
62.20.D-
Opis:
Acoustic attenuation due to phonon-phonon interaction, thermoelastic mechanism and dislocation damping were evaluated in uranium monopnictides (viz. UN, UAs and USb) in the temperature range 50-500 K, along the three crystallographic directions of propagation, viz. [100], [110] and [111] for longitudinal and shear modes of propagation. Due to antiferromagnetic property of these compounds ultrasonic attenuation due to magnon-phonon interaction was also obtained. The second- and third-order elastic moduli of B1-type uranium monopnictides were obtained using electrostatic and the Born repulsive potentials. Gruneisen numbers and acoustic coupling constants were evaluated for longitudinal and shear waves along different directions of propagation and polarization. Results were discussed and compared with available data. It was found that the temperature dependence of attenuation due to phonon-phonon interaction and thermoelastic loss mechanisms follow the third and fourth order polynomial fit laws, respectively, and acoustic attenuation is mainly governed by phonon-phonon interaction in this temperature range.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 664-670
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First tillodont from India: Additional evidence for an early Eocene faunal connection between Europe and India?
Autorzy:
Rose, K D
Rana, R.S.
Sahni, A.
Kumar, K.
Singh, L.
Smith, T.
Powiązania:
https://bibliotekanauki.pl/articles/22886.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
tillodont
India
Europe
Eocene
Paleocene
faunal connection
Cenozoic
mammal
Ypresian
anthracobunid
lagomorph
fauna
Opis:
Vastan Lignite Mine in southeastern Gujarat, India, produces the oldest known Cenozoic land−mammals and the only early Eocene continental vertebrate fauna known from India (e.g., Bajpai et al. 2005; Rana et al. 2005, 2008; Rose et al. 2006, 2008, 2009; Smith et al. 2007; Rage et al. 2008). The fauna comes from the Cambay Shale Formation and has been dated as middle Ypresian (~52 Ma, early Cuisian) based on a common nummulitid foraminiferan from about 15 m above the vertebrate−producing layer (Sahni et al. 2006; Rana et al. 2008). However, a recent study of dinoflagellate cysts from the section suggests that the deposits may be as old as 54–55 Ma (Garg et al. 2008). Although some elements of the fauna, such as anthracobunids and lagomorphs, have Asian affinities, a surprising number of taxa among the snakes, bats, insectivores, primates, rodents, and artiodactyls appear to be most closely related to early Eocene European or North American taxa. This may simply reflect the poor state of knowledge of contemporary south Asian vertebrate faunas; alternatively, it might be evidence of previously unsuspected early Eocene faunal exchange between Europe and southwest Asia. We report here two teeth of a tillodont from Vastan Mine, which constitute the first record of the mammalian order Tillodontia known from India. Despite the much greater generic diversity of tillodonts in Asia than elsewhere, the Vastan tillodont shows clear affinities with Euramerican esthonychines.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 351-355
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric studies and simulation of PSA process for oxygen production from air
Autorzy:
Beeyani, A.
Singh, K.
Vyas, R.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/779567.pdf
Data publikacji:
2010
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
amplituda ciśnienia adsorpcji
model matematyczny
symulacja
produkcji tlenu
MATLAB
Zeolit5A
pressure swing adsorption
mathematical model
simulation
oxygen production
Zeolite 5A
Opis:
A numerical simulation and parametric studies for the separation of air using 5A zeolite for the production of oxygen are presented for a basic two bed pressure swing adsorption (PSA) process. The simulation is based on an in-house program 'PSASOL' developed in MATLABŽ. The transient process of PSA has been described by a set of partial differential equations, which were solved using a finite difference method. Simulation results have been validated with the experimental data from literature. Based on the simulation results, an optimal set of operational parameter values has been obtained for the PSA bed. The values of the optimal parameters, viz. adsorption pressure, cycle time, feed rate, and product rate have been found to be 2.5 atm, 150 s, 15 cm3/s, and 2.55 cm3/s, respectively. For the optimal conditions, purity of 95.45% and recovery of 77.3% have been achieved. It has also been found that a longer tubular unit with the length to diameter (L/D) ratio of 10.5 is advantageous. The estimated pressure drop across the bed has been found to be negligible. Power consumption and productivity have also been computed.
Źródło:
Polish Journal of Chemical Technology; 2010, 12, 2; 18-28
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Comparison of Protection Strategies in WDM Mesh Networks
Autorzy:
Singh, H. K.
Aggarwal, S.
Singh, S.
Mohapatra, B.
Nagaria, R. K.
Tiwari, S.
Powiązania:
https://bibliotekanauki.pl/articles/308073.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
blocking probability
protection
survivability
switching time
WDM networks
Opis:
Recent development in optical networking employing wavelength division multiplexing (WDM) fulfills the high bandwidth demand applications. Failure of such networks, leads to enormous data and revenue loss. Protection is one of the key techniques, which is used in designing survivable WDM networks. In this paper we compare dedicated and shared protection strategies employed inWDMmesh networks to protect optical networks failure, particularly fiber failure. Dijkstra's shortest path algorithm is considered for carrying out simulations. The paper compares the performance of protection schemes, such as, dedicated path protection (DPP), shared path protection (SPP) and shared link protection (SLP) schemes. Capacity utilization, switching time and blocking probability are the parameters considered to measure the performance of the protection schemes. Simulation results show that, SPP is more efficient in terms of capacity utilization over DPP and SLP schemes, whereas, SLP offered better switching time than both DPP and SPP schemes. The average call drop rate is minimum for shared path protection scheme and maximum for shared link protection scheme.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 1; 62-69
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of inertia in the steady state pressurised flow of a non-Newtonian fluid between two curvilinear surfaces of revolution: Rabinowitsch fluid model
Autorzy:
Singh, U. P.
Gupta, R.S.
Kapur, V.K.
Powiązania:
https://bibliotekanauki.pl/articles/185617.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
efekt bezwładności
łożysko krzywoliniowe
zewnętrzny przepływ ciśnieniowy
curvilinear bearings
Rabinowitsch fluid model
inertia effect
externally pressurized flow
Opis:
In many practical situations fluids are normally blended with additives (viscosity index improvers, viscosity thickeners, viscosity thinners) due to which they show pseudoplastic and dilatant nature which can be modelled as cubic stress model (Rabinowitsch model). The cubic stress model for pseudoplastic fluids is adopted because Wada and Hayashi have shown that the theoretical results with this model are in good agreement with the experimental results. The present theoretical analysis is to investigate the pseudoplastic effect along with the effect of rotational inertia on the pressure distribution, frictional torque and fluid flow rate of externally pressurised flow in narrow clearance between two curvilinear surfaces of revolution. The expression for pressure has been derived using energy integral approach. To analyse and discuss the effects of pseudoplasticity and fluid inertia on the pressure distribution, fluid flow rate and frictional torque, the examples of externally pressurised flow in the clearance between parallel disks and concentric spherical surfaces have been considered.
Źródło:
Chemical and Process Engineering; 2011, 32, 4; 333-349
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
TBI Calculations of the Elastic Properties and Structural Phase Transformation in Novel Materials: Yttrium Nitride
Autorzy:
Singh, S.
Chauhan, R.
Gour, A.
Powiązania:
https://bibliotekanauki.pl/articles/1492770.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.K-
62.20.de
62.50.-p
Opis:
We have carried out high pressure theoretical structural studies of yttrium nitride to examine the phase transition phenomena from the NaCl structure to CsCl structure by using a three-body potential model. The phase transition pressure (140 GPa) predicted by this approach is close to the phase transition pressure, predicted by others (138 GPa). Yttrium nitride is a novel and less explored material. Under high pressure yttrium nitride goes through a sudden collapse in volume showing the first order phase transition. To understand the effect of pressure we studied bulk properties, elastic constants and their combination. The pressure volume equation of state provides meaningful signatures of physical and chemical phenomena under high pressure. Moreover we have successfully checked the stability criterion for this compound.
Źródło:
Acta Physica Polonica A; 2011, 120, 6; 1021-1025
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assay of the Insensitive High Explosive FOX-7 by Non-Aqueous Titration
Autorzy:
Nandi, A. K.
Paramasivan, P.
Singh, S. K.
Mandal, A. K.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358156.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
1,1-diamino-2,2-dinitroethene
FOX-7
non-aqueous titration
N,N-dimethylformamide
Opis:
A non-aqueous titration method was developed to assay the insensitive high explosive 1,1-diamino-2, 2-dinitroethene (FOX-7). The weak acidic nature of FOX-7 (pKa 10.6) was exploited in the assay method. The sample was dissolved in the protophilic solvent N, N-dimethylformamide and titrated against sodium methoxide solution in benzene/methanol using azo violet as indicator. FOX-7 samples obtained from regular batch operations were assayed by this method and the results were compared with that of a recrystallized sample. The method is simple, rapid and has good accuracy and precision.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 4; 343-352
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of demand boosting policy on optimal inventory policy for imperfect lot size with backorder in fuzzy environment
Autorzy:
Yadav, D.
Singh, S. R.
Kumari, R.
Powiązania:
https://bibliotekanauki.pl/articles/206244.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
learning curve
advertisement
signed distance
triangular fuzzy number
backorder
inventory model
Opis:
This paper investigates an Economic Order Quantity (EOQ) model with backorder by taking imprecise demand rate with dependence upon the frequency of advertisement. The formulated model also incorporates learning effects on percentage of defective items present in each lot. Due to imprecision in demand, the obtained profit function is fuzzy. To determine the optimal values, we determine the equivalent crisp profit function by applying the signed distance method. Optimal order quantity and backorder level are obtained by using algebraic method in place of differential calculus. A numerical example is used to study the behavior of the model with respect to different inventory parameters. All calculations are performed with MATLAB 7.4.
Źródło:
Control and Cybernetics; 2012, 41, 1; 191-212
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Tungsten on Aluminized Melt Cast High Explosive Formulations
Autorzy:
Mishra, V. S.
Bhagat. A., L.
Vadali, S. R.
Singh, V. K.
Wasnik, R. D.
Asthana, S.
Powiązania:
https://bibliotekanauki.pl/articles/358355.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
tungsten
MOUT
low intensity conflict
peak over pressure
impulse
Opis:
Aluminized 2,4,6-trinitrotoluene (TNT) based, melt-cast, high explosive compositions are widely used in warheads. These compositions offer a blast effect over a larger period due to the secondary combustion of aluminum. During recent times tungsten based explosives have been reported for lethality at close range to avoid collateral damage in low intensity conflicts (LIC) and find application in shaped charges to enhance their penetration capability. This paper reports findings on tungsten-based, melt-cast, explosive formulations. The compositions were prepared by substituting aluminum with tungsten in the reference aluminized, high explosive formulation. The compositions were characterized for their sensitivity to mechanical/shock stimuli, velocity of detonation (VOD) and blast performance. The study reveals that the impact sensitivity remains comparable on incorporating 10% tungsten at the cost of aluminum whereas an increase in tungsten content to 20% leads to an increase in impact sensitivity. However friction sensitivity and shock sensitivity remained more or less unchanged. The velocity of detonation (VOD) of tungsten-loaded, aluminized formulations is found to be comparable to the standard aluminized formulation. The peak over pressure of tungsten-based formulations is lower than the reference, aluminized composition at close range but is almost unchanged at long range. The impulse of tungsten-based formulations is also lower than the reference, aluminized composition. The reduction in impulse at close range is substantial on replacing 10% aluminum with inert tungsten.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 2; 147-154
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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