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


Tytuł:
Reliability analysis and prediction for time to failure distribution of an automobile crankshaft
Analiza niezawodności i przewidywanie rozkładu czasu do uszkodzenia wału korbowego pojazdu samochodowego
Autorzy:
Singh, S. S. K.
Abdullah, S.
Mohamed, N. A. N.
Powiązania:
https://bibliotekanauki.pl/articles/301436.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability
time to failure
monotonic function
hazard rate
niezawodność
czas do uszkodzenia
funkcja monotoniczna
wskaźnik zagrożenia
Opis:
This paper emphasizes on analysing and predicting the reliability of an automobile crankshaft by analysing the time to failure (TTF) through the parametric distribution function. The TTF was modelled to predict the likelihood of failure for crankshaft during its operational condition over a given time interval through the development of the stochastic algorithm. The developed stochastic algorithm has the capability to measure the parametric distribution function and validate the predict the reliability rate, mean time to failure and hazard rate. T, the algorithm has the capability to statistically validate the algorithm to obtain the optimal parametric model to represent the failure of the component against the actual time to failure data from the local automobile industry. Hence, the validated results showed that the three parameter Weibull distribution provided an accurate and efficient foundation in modelling the reliability rate when compared with the actual sampling data. The suggested parametric distribution function can be used to improve the design and the life cycle due to its capability in accelerating and decelerating the mechanism of failure based on time without adjusting the level of stress. Therefore, an understanding of the parametric distribution posed by the reliability and hazard rate onto the component can be used to improve the design and increase the life cycle based on the dependability of the component over a given period of time. The proposed reliability assessment through the developed stochastic algorithm provides an accurate, efficient, fast and cost effective reliability analysis in contrast to costly and lengthy experimental techniques.
W prezentowanej pracy przedstawiono metodę analizy oraz predykcji niezawodności wału korbowego pojazdu samochodowego opartą na analizie czasu do uszkodzenia (TTF) z wykorzystaniem funkcji rozkładu parametrycznego. W artykule, stworzono model TTF pozwalający na przewidywanie prawdopodobieństwa uszkodzenia wału korbowego w stanie pracy w danym przedziale czasu za pomocą nowo opracowanego algorytmu stochastycznego. Opracowany algorytm stochastyczny umożliwia mierzenie funkcji rozkładu parametrycznego oraz weryfikację przewidywanego współczynnika niezawodności, średniego czasu do uszkodzenia oraz współczynnika zagrożenia. Algorytm daje możliwość statystycznej weryfikacji modelu w odniesieniu do rzeczywistych danych dotyczących czasu do uszkodzenia pochodzących z lokalnego przemysłu samochodowego. Weryfikacja taka pozwala na otrzymanie optymalnego modelu parametrycznego reprezentującego uszkodzenie części składowej. Zweryfikowane wyniki wykazały, że trójparametrowy rozkład Weibulla stanowi dokładne i wydajne narzędzie do modelowania współczynnika niezawodności w zestawieniu z rzeczywistymi danymi z próby. Proponowaną dystrybuantę parametryczną można wykorzystywać do doskonalenia konstrukcji oraz cyklu życia wału korbowego ponieważ daje ona możliwość przyspieszania i zwalniania mechanizmu uszkodzenia, na podstawie czasu, bez potrzeby regulacji poziomu naprężenia. Zatem, znajomość rozkładu parametrycznego oraz obliczonych na jego podstawie współczynników niezawodności i zagrożenia omawianego elementu mechanizmu korbowego, pozwala na doskonalenie konstrukcji oraz wydłużenie cyklu życia wału korbowego w oparciu o dane dotyczące jego niezawodności w danym okresie czasu. Proponowana metoda oceny niezawodności z wykorzystaniem opracowanego w artykule algorytmu stochastycznego umożliwia dokładną, wydajną, szybką i tanią analizę niezawodności w odróżnieniu od kosztownych i czasochłonnych technik eksperymentalnych.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 3; 408-415
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical properties and different methods of estimation for extended weighted inverted Rayleigh distribution
Autorzy:
Yadav, Abhimanyu Singh
Singh, S. K.
Singh, Umesh
Powiązania:
https://bibliotekanauki.pl/articles/1363558.pdf
Data publikacji:
2020-06-05
Wydawca:
Główny Urząd Statystyczny
Tematy:
moments and inverse moments
entropy measurements
order statistics
classical methods of estimation
Opis:
The aim of this paper is to introduce a new weighted probability distribution to model the non-monotone failure rate pattern for survival data. The proposed distribution is generalized by considering inverted Rayleigh distribution as a baseline distribution called an extended weighted inverted Rayleigh distribution. Different statistical properties such as moment, quantile function, moment generating function, entropy measurement, Bonferroni and Lorenz curve, stochastic ordering and order statistics have been derived. Different estimation procedures have also been discussed to estimate the unknown parameters of the proposed probability distribution. The Monte Carlo simulation study has been conducted to compare the performances of the proposed estimators obtained through various methods of estimation. Finally, two real data sets have been used to show the applicability of the proposed model in a real-life scenario.
Źródło:
Statistics in Transition new series; 2020, 21, 2; 119-141
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static, vibration and buckling analysis of skew composite and sandwich plates under thermo mechanical loading
Autorzy:
Singh, S. K.
Chakrabarti, A.
Powiązania:
https://bibliotekanauki.pl/articles/264605.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda elementów skończonych
obciążenie cieplne
płyta warstwowa
skew plate
finite element
refined theory
thermal load
Opis:
Static, vibration and buckling behavior of laminated composite and sandwich skew plates is studied using an efficient C0 FE model developed based on refined higher order zigzag theory. The C0 FE model satisfies the interlaminar shear stress continuity at the interfaces and zero transverse shear stress conditions at plate top and bottom. In this model, the first derivatives of transverse displacement have been treated as independent variables to overcome the problem of C1 continuity associated with the plate theory. The C0 continuity of the present element is compensated in the stiffness matrix formulation by adding a suitable term. In order to avoid stress oscillations observed in the displacement based finite element, the stress field derived from temperature is made consistent with the total strain field by using field consistent approach. Numerical results are presented for different static, vibration and buckling problems by applying the FE model under thermo mechanical loading, where a nine noded C0 continuous isoparametric element is used. It is observed that there are very few results available in the literature on laminated composite and sandwich skew plates based on refined theories. As such many new results are also generated for future reference.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 3; 887-898
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Class of Chain Ratio-Cum-Dual to Ratio Type Estimator with Two Auxiliary Characters Under Double Sampling in Sample Surveys
Autorzy:
Choudhury, S.
Singh, B. K.
Powiązania:
https://bibliotekanauki.pl/articles/465944.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
auxiliary variate
double sampling
chain ratio-cum-dual to ratio estimator
bias
variance
efficiency
Opis:
This paper considers a chain ratio-cum-dual to ratio type estimator for estimating population mean of the study variate using two auxiliary variates under double (two-phase) sampling procedure, when the information on another additional auxiliary variate is available along with the main auxiliary variate. The asymptotically optimum estimators (AOEs) in the class are identified in two different cases with their bias and variances. The optimum values of the first phase and second phase sample sizes have been obtained for the fixed cost of survey. Theoretical and empirical studies have also been done to demonstrate the efficiency of the proposed estimator with respect to strategies which utilized the information on two auxiliary variates.
Źródło:
Statistics in Transition new series; 2012, 13, 3; 519-536
1234-7655
Pojawia się w:
Statistics in Transition new series
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:
Impact of dispersion order on optical millimetre-wave generation based on series optical external modulators without an optical filter
Autorzy:
Singh, M.
Raghuwanshi, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/174512.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber chromatic dispersion
microwave photonics
radio-over-fiber
dual-drive Mach–Zehnder modulator
Opis:
The influence of higher order fiber dispersions (like chromatic dispersion and dispersion slope) on the optical millimeter-wave generation is studied. Optical sideband suppression ratio and radio frequency spurious suppression ratio are given and discussed. Moreover, the mathematical results of the proposed model are verified by experiments and numerical simulations.
Źródło:
Optica Applicata; 2015, 45, 2; 215-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
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:
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:
Linear stability analysis for ferromagnetic fluids in the presence of magnetic field, compressibility, internal heat source and rotation through a porous medium
Autorzy:
Kumar, K.
Singh, V.
Sharma, S.
Powiązania:
https://bibliotekanauki.pl/articles/279562.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ferrofluids
rotation
magnetic field
porous medium
heat source
compressibility
Opis:
The effects of magnetic field and heat source strength on thermal convection of a compressible rotating ferromagnetic fluid through a porous medium are investigated theoretically using linear stability theory. A normal mode analysis method is employed to find solutions for the fluid layer confined between parallel planes with free boundaries. The cases of stationary and oscillatory instabilities are discussed. For the stationary state, compressibility, medium porosity and temperature gradient due to heat source have destabilizing effects, whereas rotation and ratio of magnetic permeability delay the onset of convection. The magnetic field and medium permeability have both stabilizing and destabilizing effects under certain conditions. The variations in the stationary critical thermal Rayleigh number and neutral instability curves in (Ra1, x)-plane for various values of physical parameters are shown graphically to depict the stability characteristics. The sufficient conditions for the non-existence of overstability are obtained and the principle of exchange of stabilities holds true in the absence of magnetic field and rotation under certain conditions.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 1067-1081
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-Certainty-Equivalent Adaptive Control of a Nonlinear Aeroelastic System
Autorzy:
Lee, K. W.
Singh, S. N.
Powiązania:
https://bibliotekanauki.pl/articles/226734.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aeroelastic wing
adaptive flutter control
nonlinear system
immersion and invariance method
uncertain system
Opis:
The development of a non-certainty-equivalent adaptive control system for the control of a nonlinear aeroelastic system is the subject of this paper. The prototypical aeroelastic wing section considered here includes structural nonlinearity and a single control surface for the purpose of control. Its dynamical model has two-degree-of-freedom and describes the plunge and pitch motion. It is assumed that the model parameters (except the sign of one of the control input coefficients) are not known. The uncontrolled aeroelastic model exhibits limit cycle oscillation beyond a critical free-stream velocity. Based on the attractive manifold, and the immersion and invariance methodologies, a non-certainty-equivalent adaptive state variable feedback control law for the trajectory tracking of the pitch angle is derived. Using the Lyapunov analysis, asymptotic convergence of the state variables to the origin is established. It is shown that the trajectory of the system converges to a manifold. The special feature of the designed control system is that the closed-loop system asymptotically recovers the performance of a deterministic controller. This cannot happen if certainty-equivalent adaptive controllers are used. Simulation results are presented which show that the control system suppresses the oscillatory responses of the system in the presence of large parameter uncertainties.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 4; 463-471
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular Interaction Study of Binary Mixtures of THF with Methanol and o-Cresol - an Optical and Ultrasonic Study
Autorzy:
Parveen, S.
Singh, S.
Shukla, D.
Singh, K.
Gupta, M.
Shukla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1585019.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.35.+d
62.60.+v
82.60.Lf
Opis:
The refractive indices, densities and ultrasonic velocities of binary liquid mixtures of tetrahydrofuran (THF) with methanol and o-cresol over the entire composition range have been measured at 293, 303 and 313 K. Refractive index, density and ultrasonic velocity data have been used to evaluate the molar refraction deviation $ΔR_{m}$, deviation in ultrasonic velocity Δu, excess internal pressure $π_{i}^{E}$, excess molar enthalpy $H_{m}^{E}$ and excess free volume $V_{f}^{E}$. The computed results of $ΔR_{m}$, Δu, $π_{i}^{E}$, $H_{m}^{E}$ and $V_{f}^{E}$ were fitted to the Redlich-Kister polynomial equation. These results suggest that specific strong interactions are taking place in THF + o-cresol mixture while dispersive forces seem to be responsible for behaviour of THF + methanol mixture. Further, experimental refractive index and density data of these mixtures were also used to test the validity of the empirical/semi-empirical relations and models for refractive index and density, respectively.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 1011-1017
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genetic variability, inheritance and correlation for mineral contents in cabbage (Brassica oleracea var. capitata L.)
Autorzy:
Singh, B.K.
Sharma, S.R.
Singh, B.
Powiązania:
https://bibliotekanauki.pl/articles/2100.pdf
Data publikacji:
2013
Wydawca:
Instytut Ogrodnictwa
Tematy:
cabbage
Brassica oleracea var.capitata
genetic variability
inheritance
mineral content
dietary mineral
iron
zinc
copper
manganese
potassium
calcium
heritability
Źródło:
Journal of Horticultural Research; 2013, 21, 1
2300-5009
Pojawia się w:
Journal of Horticultural Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaotic convection of viscoelastic fluid in porous medium under G-jitter
Autorzy:
Bhadauria, B. S.
Singh, A.
Singh, M. K.
Powiązania:
https://bibliotekanauki.pl/articles/265559.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
teoria nieliniowa
grawitacja
konwekcja
non-linear theory
gravity modulation
chaotic convection
Opis:
The present article aims at investigating the effect of gravity modulation on chaotic convection of a viscoelastic fluid in porous media. For this, the problem is reduced into Lorenz system (non-autonomous) by employing the truncated Galerkin expansion method. The system shows transitions from periodic to chaotic behavior on increasing the scaled Rayleigh number R. The amplitude of modulation advances the chaotic nature in the system while the frequency of modulation has a tendency to delay the chaotic behavior which is in good agreement with the results due to [1]. The behavior of the scaled relaxation and retardation parameter on the system is also studied. The phase portrait and time domain diagrams of the Lorenz system for suitable parameter values have been used to analyze the system.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 1; 37-51
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis and internal heating effect on oscillatory convection in a viscoelastic fluid saturated porous medium under gravity modulation
Autorzy:
Bhadauria, B. S.
Singh, M. K.
Singh, A.
Singh, B. K.
Kiran, P.
Powiązania:
https://bibliotekanauki.pl/articles/265014.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
analiza stabilności
grawitacja
ciecz lepkosprężysta
nonlinear stability analysis
complex Ginzburg-Landau equation
gravity modulation
internal heating
bifurcation
Opis:
In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 785-803
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation and sensitivity analysis for biodiesel production in a reactive distillation column
Autorzy:
Agarwal, M.
Singh, K.
Chaurasia, S. P.
Powiązania:
https://bibliotekanauki.pl/articles/779118.pdf
Data publikacji:
2012
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
biodiesel
reactive distillation
modeling
simulation
transesterification
sensitivity analysis
Opis:
The conventional process for biodiesel production by transesterification is still expensive due to a need of high excess of alcohol required and its recovery by distillation. The use of a reactive distillation process can reduce the amount of alcohol in the feed stream as it works on a simultaneous reaction and separation. In the present study, a mathematical model has been developed for biodiesel production from triglycerides in a reactive distillation column, which has been validated with the reported data and CHEMCAD results. The effects of process parameters such as methanol to oil feed ratio, feed temperature, and reaction time have been investigated. The sensitivity analysis shows that yield of ester increases with methanol to oil ratio and number of stages, however, it decreases with fl ow rate. The MATLAB simulated results show that methanol to oil molar ratio of 5:1 produces 90% (by wt.) of methyl ester in a residence time of 4.7 minutes.
Źródło:
Polish Journal of Chemical Technology; 2012, 14, 3; 59-65
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of chemically reactive species and thermal radiation effects on an unsteady MHD free convection flow through a porous medium past a flat plate with ramped wall temperature
Autorzy:
Pandit, K. K.
Sarma, D.
Singh, S. I.
Powiązania:
https://bibliotekanauki.pl/articles/264711.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
free convection
chemical reaction
thermal radiation
MHD
porous medium
ramped temperature
konwekcja swobodna
reakcja chemiczna
promieniowanie cieplne
magnetohydrodynamika
ośrodek porowaty
Opis:
An investigation of the effects of a chemical reaction and thermal radiation on unsteady MHD free convection heat and mass transfer flow of an electrically conducting, viscous, incompressible fluid past a vertical infinite flat plate embedded in a porous medium is carried out. The flow is induced by a general time-dependent movement of the vertical plate, and the cases of ramped temperature and isothermal plates are studied. An exact solution of the governing equations is obtained in closed form by the Laplace Transform technique. Some applications of practical interest for different types of plate motions are discussed. The numerical values of fluid velocity, temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters for both ramped temperature and isothermal plates.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 4; 945-964
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isolation and computational characterization of glutathione peroxidase gene from an aquatic fern - Salvinia molesta
Autorzy:
Rahaman, S.
Singh, P.K.
Basu, P.
Gupta, S.
Basu, M.
Ganguli, S.
Powiązania:
https://bibliotekanauki.pl/articles/11200.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Pteridophytes and more specifically ferns represent a large but threatened group of plants which often serve as important environmental markers for pollution. Reports regarding stress responses in ferns are rare, apart from a few studies involving the ecological distribution and molecular marker studies. This work isolates a glutathione peroxidase enzyme from an aquatic fern widely distributed in fresh and polluted water bodies adjacent to sources of environmental polluted sources. Further computational analyses were performed to study the structure of the protein encoded by the open reading frame. Results indicate the presence of a large number of binding pockets which serve as important binding sites in the interactions with the cognate ligands.
Źródło:
International Letters of Natural Sciences; 2016, 51
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Ammonium Sulfamate Nitration for the Preparation of Ammonium Dinitramide
Autorzy:
Mandal, A. K.
Kunjir, G. M.
Singh, J.
Adhav, S. S.
Singh, S. K.
Pandey, R. K.
Bhattacharya, B.
Lakshmi Kantam, M.
Powiązania:
https://bibliotekanauki.pl/articles/358022.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Opis:
The reaction kinetics for the preparation of ammonium dinitramide (ADN) is described. ADN is the ammonium salt of the dinitramide anion, and belongs to the group of inorganic oxidizers, mainly useful for energetic rocket propellant formulations, particularly for underwater applications. It is also a potential candidate to replace ammonium perchlorate (AP), in order to develop chlorine-free, green propellants. At HEMRL, ADN is prepared by the nitration of ammonium sulfamate (AS) using mixed acid, followed by hydrolysis, neutralization with ammonia (g) and rectification using solvent. The nitration of ammonium sulfamate (AS) is carried out at a subzero temperature of -40 ±1 °C. The yield of ADN is reliant on the formation of dinitramidic acid, an intermediate product formed during the hydrolysis step, and its stability is predominantly dependent upon the level of acidity and temperature of the reaction medium. Prior to these kinetics studies, process optimization of the nitration of ammonium sulfamate (AS) was performed and gave the final mole ratio of AS:HNO3:H2SO4. Since the nitration of AS is sensitive to temperature, the rate of reaction was studied at fixed temperatures with variation of time, keeping all of the other parameters, such as vessel volume, agitator speed, feed rate etc., constant. During these studies, predetermined quantities of ammonium sulfamate (AS) and mixed acid were allowed to react at a fixed temperature (-40 ±1 °C) for different reaction periods to generate the concentration profile of AS. Using this concentration profile, the reaction order and reaction rate constant were evaluated. In order to find the effect of temperature on the reaction rate and yield, experiments were conducted at other temperatures such as -30 and -50 °C. In the present studies, it was found that the optimum temperature of nitration is -40 ±1 °C and that the rate of reaction follows a pseudo second order process with rate constant 0.01113 (min-1)•(mol/L)-1. The reaction time evaluated for 55 to 60% conversion is about 70-80 minutes at -40 ±1 °C, based on this kinetics. The activation energy of AS nitration was found to be -4.6 kcal/mol, using the reaction kinetic data based on the temperature dependent rate equation derived from Arrhenius’s law.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 1; 83-97
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Public goods and externalities: new direction for CAP in the post 2013 period
Dobra publiczne i efekty zewnętrzne - nowy kierunek rozwoju WPR po 2013 roku
Autorzy:
Vasary, M.
Singh, M.K.
Buzas, S
Powiązania:
https://bibliotekanauki.pl/articles/864581.pdf
Data publikacji:
2010
Wydawca:
The Polish Association of Agricultural and Agribusiness Economists
Opis:
The CAP is in an important reform phase. In this process will be reorganized the principles and functioning, so will be by the argumentation even importer the common interest and the public goods. In this process must be focus on some challenges by the provision of environmental public goods.
Wspólna polityka rolna UE jest w fazie znaczących zmian związanych z nową perspektywą finansową po 2013 roku. W procesie tym istotną rolę przypisuje się dobrom publicznym. Artykuł omawia zagadnienia środowiskowych dóbr publicznych w kontekście reform WPR.
Źródło:
Roczniki Naukowe Stowarzyszenia Ekonomistów Rolnictwa i Agrobiznesu; 2010, 12, 6
1508-3535
2450-7296
Pojawia się w:
Roczniki Naukowe Stowarzyszenia Ekonomistów Rolnictwa i Agrobiznesu
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resource scheduling in cloud environmet: a survey
Autorzy:
Mangla, N.
Singh, M.
Rana, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/102866.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
resource scheduling
energy conservation
cloud computing
virtualization
service level agreement
Opis:
Cloud Computing offers the avant-garde services at a stretch that are too attractive for any cloud user to ignore. With its growing application and popularization, IT companies are rapidly deploying distributed data centers globally, posing numerous challenges in terms of scheduling of resources under different administrative domains. This perspective brings out certain vital factors for efficient scheduling of resources providing a wide genre of characteristics, diversity in context of level of service agreements and that too with user-contingent elasticity. In this paper, a comprehensive survey of research related to various aspects of cloud resource scheduling is provided. A comparative analysis of various resource scheduling techniques focusing on key performance parameters like Energy efficiency, Virtual Machine allocation and migration, Cost-effectiveness and Service-Level Agreement is also presented.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 30; 38-50
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A short history of india’s economy: pre- and post-independence period
Krótka historia gospodarki Indii: w okresie przed i po odzyskaniu niepodległości
Autorzy:
Shrotryia, V.K.
Singh, S.V.P.
Powiązania:
https://bibliotekanauki.pl/articles/2051179.pdf
Data publikacji:
2020
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
economic history
growth history
India
political economy
pre-independence period
postindependence period
Opis:
India is one of the most populated countries in the world and was famously known as the golden bird. It was known for its rich cultural heritage and some of the world’s most significant educational institutions. Over the countless decades and centuries, the invaders exploited the resources for their advantage. At the decline of the independence in 1947, it was left backward with one of the poorest economies of the world of that time. The richness of erstwhile India, the status of the golden bird, the sacred intellectual space that India occupied has only textual value for the present generation. Through this academic paper, an attempt has been made to address the following questions: what was the state of the economy of India during the pre- and post-independence period, how has India transformed herself from one of the most impoverished economies in 1947 to currently the third-largest economy in the world, and how is the current economic and non-economic status of India.
Źródło:
Economic and Regional Studies; 2020, 13, 4; 388-406
2083-3725
2451-182X
Pojawia się w:
Economic and Regional Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of guava trees (Psidium guajava) to soil applications of mineral and organic fertilisers and biofertilisers under conditions of low fertile soil
Autorzy:
Shukla, S.K.
Adak, T.
Singha, A.
Kumar, K.
Singh, V.K.
Singh, A.
Powiązania:
https://bibliotekanauki.pl/articles/1946.pdf
Data publikacji:
2014
Wydawca:
Instytut Ogrodnictwa
Tematy:
guava
Psidium guajava
organic fertilizer
vermicompost
mulching
mineral fertilizer
biofertilizer
plant nutrition
plant growth
yield
fruit quality
Źródło:
Journal of Horticultural Research; 2014, 22, 2
2300-5009
Pojawia się w:
Journal of Horticultural Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioremediation of melanoidin contamination in distillery effluent using Aspergillus brasiliensis
Autorzy:
Singh, T.A.
Singh, T.
Singh, R.
Pandey, P.K.
Gaur, R.
Jamal, F.
Patel, S.K.
Bansal, S.
Powiązania:
https://bibliotekanauki.pl/articles/2097092.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spent wash
effluent
melanoidin
bioremediation
decolorization
Opis:
The current investigation is the first report of utilization of Aspergillus brasiliensis for the decolorization of melanoidin in distillery effluent. The effluent generated from alcohol distilleries is one of the most complex wastewater with a high biological oxygen demand (BOD) and other organic, inorganic, and toxic constituents. The effluent contains melanoidin, a dark brown compound, which is difficult to remediate by using conventional technologies. The disposal of spent wash in the natural environment is hazardous and can deteriorate land and water resources. The decolorization of spent wash through physical and chemical methods remains unsuitable, and the only alternative to decolorize spent wash is biological treatment. In the current study, three fungal strains were isolated from the distillery waste and screened for their ability to decolorize melanoidin.The isolate RS2 exhibited maximum decolorization of 83% and was identified as Aspergillus brasiliensis. Its optimum growth temperature was 37EC, and the maximum efficiency was recorded after 120 h of incubation. Nutritional sources were investigated for the fungi showing the maximum decolorization of melanoidin, and starch and peptone were found to be the best carbon and nitrogen sources, respectively. At 1.5% starch concentration and 1.5% peptone concentration, the decolorization level attained was 87.45% and 88.74%, respectively. A. brasiliensis exhibited a high potential to decolorize melanoidin. The decolorization percentage was high, which makes this fungus a potential candidate for use at the industrial scale for the bioremediation of spent wash.
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2020, 101, 3; 205-213
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plant community characteristics and soil status in different land use systems in Dimapur district, Nagaland, India
Autorzy:
Singh, S.K.
Kumar, K.W.
Aier, B.
Kanduri, V.P.
Ahirwar, S.
Powiązania:
https://bibliotekanauki.pl/articles/45630.pdf
Data publikacji:
2012
Wydawca:
Instytut Badawczy Leśnictwa
Źródło:
Leśne Prace Badawcze; 2012, 73, 4
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study into occurrence of fire in opencast workings over developed coal pillars and evolving control parameters for its safe extraction
Badanie przypadku wystąpienia pożaru w wyrobiskach odkrywkowych ponad udostępnianymi filarami węglowymi i opracowanie parametrów kontrolnych dla zapewnienia ich bezpiecznego wydobycia
Autorzy:
Panigrahi, D.
Sinha, S. K.
Singh, G. N.
Powiązania:
https://bibliotekanauki.pl/articles/219289.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
prowadzenia odkrywki powyżej filarów podziemnych udostępnionych metodą filarowo-komorową
parametry krytyczne określające możliwość wystąpienia pożaru
parametry górnicze
przegląd krytyczny
parametry związane z wydobyciem
przedział ufności
analiza wariancji
opencast over underground bord and pillars
critical to fire
mining parameters
critical review
mine operational parameters
confidence interval and analysis of variance
Opis:
In India, a number of opencast mines are being worked over the coal pillars developed by underground bord and pillar method of mining. In these cases, the fires have occurred in most of these opencast mines causing loss of the coal reserve, production, productivity and safety. In this research work, 13 such mines have been studied over a period of three years and critical parameters for occurrence of these fires have been identified. This paper presents the details of observations for two such mines and detailed statistical analyses have been carried out by using confidence interval (C.I.) and analysis of variance (ANOVA-Two-way classification) for finding out the range of these critical parameters which can be controlled to reduce the occurrence of these fires.
W wielu kopalniach odkrywkowych w Indiach wydobycie prowadzi się w wyrobiskach ponad filarami ochronnymi udostępnianymi przy wykorzystaniu metody filarowo-komorowej. W takich warunkach powstające często w kopalniach pożary powodują utratę zasobów węglowych, zmniejszenie wydajności i poziomu wydobycia oraz negatywnie wpływają na bezpieczeństwo pracy. W artykule tym przeanalizowano przypadki 13 kopalni odkrywkowych na przestrzeni trzech lat, zidentyfikowano krytyczne parametry dla określenia możliwości wystąpienia pożaru. Artykuł przedstawia dokładne obserwacje poczynione w dwóch kopalniach, poparte szczegółową analizą statystyczną z zastosowaniem przedziałów ufności i analizy wariancji (ANOVA - klasyfikacja dwukierunkowa) do określenia wartości parametrów krytycznych w celu zminimalizowania ryzyka wystąpienia pożarów.
Źródło:
Archives of Mining Sciences; 2013, 58, 4; 1145-1162
0860-7001
Pojawia się w:
Archives of Mining Sciences
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:
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:
Covid-19 update: Omicron variant − a new emerging threat
Autorzy:
Mehta, S.
Gambhir, R.S.
Singh, B.
Goel, R.
Ghuman, K.S.
Aggarwal, A.
Powiązania:
https://bibliotekanauki.pl/articles/2083083.pdf
Data publikacji:
2022
Wydawca:
Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
Tematy:
COVID-19
SARS-CoV-2 pandemic
Omicron variant
vaccine
coronavirus pandemic
Opis:
A new health threat in the form of a new variant of Covid-19 called Omicron has emerged globally in this holiday season. This new variant has been declared a variant of concern (VOC) by the World Health Organization and experts are expecting another wave of the pandemic. A lot still unknown about this variant and researchers worldwide are conducting studies to find the nature and characteristics of this mutated strain. Cases have begun to rise dramatically around the world and many countries have already imposed travel restrictions again to prevent disease transmission. It is being speculated that this particular variant has got tendency of immune escape and therefore can even infect fully vaccinated individuals. Vaccination and adhering to Covid-19 guidelines and protocols can curtail the spread of the virus. The present paper focuses on what is currently known about this variant, antigen diagnostic tests, importance of getting fully vaccinated and having booster dose etc. If we want to emerge from this pandemic, countries should practice vaccine equality and solidarity for the good of mankind.
Źródło:
Roczniki Państwowego Zakładu Higieny; 2022, 73, 1; 13-16
0035-7715
Pojawia się w:
Roczniki Państwowego Zakładu Higieny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assay of the Insensitive High Explosive 3-Nitro-1,2,4-triazol-5-one (NTO) by Acid-Base Titration
Autorzy:
Nandi, A. K.
Singh, S. K.
Kunjir, G. M.
Singh, J.
Mandal, A. K.
Pandey, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358351.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
NTO
purity
acid-base titration
HPLC
quality control
Opis:
The insensitive high explosive 3-nitro-1,2,4-triazol-5-one (NTO) is a weak acid (pKa 3.76) due to the labile N–H bond. The weakly acidic character of this compound is exploited for its assay by aqueous acid-base titration. The NTO sample was dissolved in water and the resultant solution was titrated against 0.07 N NaOH solution using phenolphthalein as indicator. Regular batch samples were assayed by this method and the results were compared with those obtained by the HPLC method. The aqueous acid-base titration method was found to be suitable for the quality control of the product.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 113-122
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
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:
Effect of flux composition on the percentage elongation and tensile strength of welds in submerged arc welding
Efekt składu topnika na wydłużenie procentowe i wytrzymałość na rozciąganie spawów przy spawaniu łukiem krytym
Autorzy:
Singh, B.
Khan, Z. A.
Siddiquee, A. N.
Maheswari, S.
Sharma, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/140322.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultimate tensile strength
carbon equivalent
basicity index
elements transfer
delta quantity
UTS
wytrzymałość na rozciąganie
równoważnik węglowy
współczynnik zasadowości
transfer pierwiastków
wielkość delta
Opis:
This experimental study reveals the effects of CaF2, FeMn and NiO additions to the base fluxes on tensile strength and percentage elongation of the weld metal. The aim of this study is to develop suitable flux for mild steel for high tensile strength, impact strength and ductility. Bead on plate welds were made using submerged arc welding process. Mathematical model for percentage elongation and UTS of mild steel welds were made. The elements transfer to the welds have been correlated with the above mechanical performance characteristics. The effect of oxygen content on weld elongation and UTS also has been deduced. This study shows that CaF2 and NiO are the significant factors for tensile strength while FeMn is not significant for tensile strength. However, for elongation besides CaF2, the interaction of CaF2 and FeMn was also found significant. The effects of basicity index of the flux and carbon equivalent of the welds on tensile strength and percentage elongation of the welds have also been evaluated.
W studium eksperymentalnym, przedstawionym w pracy, pokazano wpływ domieszek CaF2, FeMn i NiO do podstawowego składu topnika na wytrzymałość na rozciąganie i procentowe wydłużenie metalu spawu. Celem studium było opracowanie topnika odpowiedniego dla stali niskowęglowej, który zapewnia wysoką wytrzymałość na rozciąganie, wytrzymałość na udary i plastyczność. Ściegi spawów wykonano metodą spawania łukiem krytym. Opracowano model matematyczny wydłużenia procentowego i wytrzymałości na rozciąganie (UTS) dla spawów ze stali niskowęglowej. Zbadano korelację między wymienionymi charakterystykami mechanicznymi a transferem pierwiastków do spawu. Wyznaczono także wpływ zawartości tlenu na wydłużenie spawu i ostateczną wytrzymałość na rozciąganie. W badaniach doświadczalnych wykazano, że domieszki CaF2 oraz NiO są istotnymi czynnikami wpływającymi na wytrzymałość na rozciąganie, podczas gdy domieszka FeMn nie ma istotnego wpływu. Oceniono także wpływ współczynnika zasadowości topnika i równoważnika węglowego spawu na wydłużenie procentowe spawu.
Źródło:
Archive of Mechanical Engineering; 2016, LXIII, 3; 337-354
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
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
Tytuł:
Change in entropy of the spinning black holes
Autorzy:
Mahto, D.
Singh, A. S.
Vineeta, K.
Kumar, A.
Powiązania:
https://bibliotekanauki.pl/articles/411895.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Event-horizon
AGN
Entropy & Energy
Opis:
Aims: To derive an expression for change in entropy of spinning black holes on the basis of the model for the energy of spinning black holes E BHs= KBHs R's ( Mahto et al. 2011a) & the model for entropy change δS bh = [wzór]δE ( Mahto et al. 2011b) and then calculate their values for different test spinning black holes. Study Design: Data for the mass of black holes have collected from the research paper entitled :Super massive Black Holes in Galactic Nuclei: Past Present & Future Research(2005), Space Science Reviews by L. Ferrarese & H. Ford and Black holes in Astrophysics(2005), New Journal Physics by R. Narayan. The data for black hole constant for spinning black holes (K BHs = 1.214x1044) is taken from the paper entitled: Study of Schwarzschild radius with reference to the spinning black holes. Bulletin of Pure and Applied Sciences (2011a). Place and Duration of Study: Department of Physics, Marwari College Bhagalpur and University Department of Physics, T.M.B.U. Bhagalpur, between December 2013 and March 2014. Methodology: A theoretical based work using Laptop to calculate the calculation for change in entropy of different test spinning black holes at Marwari College Bhagalpur and the residential research chamber of the first author. Results: The calculation shows that the change in entropy of spinning black holes of the rest masses for stellar – mass black holes (M ~ 5 – 20 Mʘ) in X-ray binaries is 2.483x10 63 to 39.731x10 63 J/K and for the super massive Black holes (M ~ 10 6 – 109.5 Mʘ) in active galactic nuclei is 9.932x10 73 to 28.432x10 80 J/K. The nature of the graph for XRBs is the same to the Hawking entropy with the event horizon and straight line for AGN which confirms the validity of equations EBHs=KBHs R’s and δS bh = [wzór]δE .Conclusion: The change in energy and entropy of black holes are mainly dependent on the mass and independent of their event horizons.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 13, 2; 95-103
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intranasal (IN) COVID-19 vaccines - a breakthrough
Autorzy:
Gambhir, R.S.
Kaur, K.
Matariya, R.
Singh, B.
Sood, R.
Singh, J.
Powiązania:
https://bibliotekanauki.pl/articles/28765534.pdf
Data publikacji:
2023
Wydawca:
Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
Opis:
Emerging variants of COVID-19 have threatened the effectiveness of intramuscular (IM) vaccines since that are made to target only the spike protein. Development of Intranasal (IN) vaccination has been proven to provide both the mucosal and systemic immune responses for broader and long lasting protection. Many IN vaccine candidates (virus-vectored vaccines, recombinant subunit vaccines and live attenuated vaccines) are in different phases of clinical trials and in near future many companies would be releasing their vaccines into the drug market. Potential advantages of IN vaccination over IM vaccination makes them ideal to be administered in children and developing populations of the world. This paper focuses on the very recent developments in intranasal vaccination with a spotlight on their safety and efficacy concerns. IN vaccination can prove to be game-changer in handling COVID-19 and potential viral contagious diseases in future.
Źródło:
Roczniki Państwowego Zakładu Higieny; 2023, 74, 1; 15-18
0035-7715
Pojawia się w:
Roczniki Państwowego Zakładu Higieny
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:
Experimental and analytical study of the side cutting ability of drill bits
Autorzy:
Tellez, C.
Singh, K.
Miska, S.
Ozbayoglu, E.
Ziaja, M.
Powiązania:
https://bibliotekanauki.pl/articles/299257.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
drill bits
directional drilling
BHA mechanics
Opis:
Side cutting ability of a drill bit is an important factor to ensure successful directional/horizontal drilling. In this study, a mathematical model of a drill bit has been developed to investigate the side cutting ability of a drill bit. In addition to the theoretical model, the study is also supported by experimental work. Experiments have been conducted for both PDC and tri-cone rotary roller drill bits. Equilibrium equations for BHA in a curved wellbore were established. The expression of internal forces and moments along the drill-string, which are the state variables, are derived. Because of the simplicity and fast computation capability, transfer matrix method (TMM) was adopted to determine these variables. Experiments were conducted on an indoor Tulsa University Drilling Research Projects (TUDRP) full-scale drilling rig. Tests have been conducted using 6 inch and 8.5 inch PDC drill bits. In addition, 8.5 inch tri-cone bit were tested as well. Bent sub was installed above the drill bit to enhance the side force at the bit. During the experiments, weight on bit (WOB) and flow rate were kept constant. The torque was recorded by torque gage. It was observed that RPM has little influence on torque. As expected, the bit side cutting abilities, also referred to as bit steer-ability, were different for different bits. For quantitative comparisons, a dimensionless quantity has been introduced that measures the relative difference in torque with bent sub and without with respect to torque without bent sub. In all tests, the torque with bent subs was found to be greater than those without. Hence, the relative difference is always positive. The higher the relative difference, the poorer the side cutting ability. For drill bits with side cutting ability equal to that of face cutting, the dimensionless quantity becomes zero. In conclusion, the main outcome of this paper is a new method of measuring face and side cutting ability for PDC and tri-cone bits. A similar approach has been applied to the analysis of data from offset wells using a computer program to predict side forces and the corresponding torques. This in turn permitted us to calculate the relative difference in torque and assess the side cutting ability of the drill bits. A comprehensive study of the side cutting ability of a drill bits missing in the current literature. Considering the important role side cutting ability plays in directional drilling, a very innovative mathematical model has been proposed to study the same. Experimental tests have been conducted to verify the model. The model can be used to analyze directional data and obtain useful information from offset wells to enhance future drilling projects.
Źródło:
AGH Drilling, Oil, Gas; 2018, 35, 1; 139-155
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoacoustical Excess Properties of Binary Liquid Mixtures - A Comparative Experimental and Theoretical Study
Autorzy:
Yasmin, M.
Singh, K.
Parveen, S.
Gupta, M.
Shukla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1808024.pdf
Data publikacji:
2009-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.35.+d
62.60.+v
82.60.Lf
Opis:
Specific heat ratio (γ), pseudo-Grüneisen parameter (Γ), heat capacity $(C_p)$ and effective Debye temperature $(θ_{D})$ for binary system of tetrahydrofuran with o-cresol and methanol respectively, were calculated using the experimentally measured densities, velocities and viscosities of the pure liquids and their mixtures over the whole composition range and at T = 293, 303, 313 K. The excess pseudo-Grüneisen parameter $(Γ ^{E})$, excess molar isentropic compressibility $(K_{s}^{E})$ and excess acoustic impedance $(Z^{E})$ were also calculated. The excess deviation functions have been correlated using Redlich-Kister polynomial equation. The observed values of the excess parameters plotted against the mole fraction of tetrahydrofuran have been explained on the basis of intermolecular interaction suggesting strong interaction in tetrahydrofuran + o-cresol than in tetrahydrofuran + methanol. Partial molar isentropic compressibility at infinite dilution and their excess values were calculated for each component. Sanchez theory, Goldsach-Sarvas volume fraction statistics, Sudgen's relation, Flory-Patterson-Rastogi and Brock and Bird model were used with the Aurebach relation to compute theoretically the values of ultrasonic velocities at varying temperatures. The velocity deviations were estimated in terms of average percentage deviations. Internal pressure for both the systems were calculated theoretically and discussed on the basis of relative applicability of the models in theoretical estimations. The isothermal compressibility $(k_T)$, for these binary mixtures were theoretically evaluated by using the Flory statistical theory and five hard sphere models and compared with the experimental values.
Źródło:
Acta Physica Polonica A; 2009, 115, 5; 890-900
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identifying overlapping phylogenetic and geographic roots of HIV - 1 evolution through computational analyses
Autorzy:
Singh, P.K.
Banik, R.
Chakraborty, H.J.
Das, S.G.
Ganguli, S.
Datta, A.
Powiązania:
https://bibliotekanauki.pl/articles/11359.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
phylogenetic root
geographic root
evolution
computational analysis
HIV-1
genome
recombinant strain
AIDS
human disease
acquired immunodeficiency syndrome zob.AIDS
acquired immune deficiency syndrome zob.AIDS
Opis:
HIV-1 or Human Immuno Deficiency Virus-1 is the main causative agent of Acquired Immuno Deficiency Syndrome (AIDS). Human host infected with HIV - 1 extensively harbours many viral variants but very little is known about the difference in pattern[17] of evolution of phylogenetic lineages of HIV-1 non recombinant, normal inter subtype recombinant and main two specific recombinant forms of HIV-1 i.e., Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs). This study is mainly concerned with study of the difference in evolutionary lineages of non-recombinant and recombinant sequences of HIV-1 genome sequences and identification of geographically rich areas which has reported high degree of HIV-1 occurrence and variety. Total 1550 HIV-1 genome sequences were obtained from HIV Los Alamos Database. The sequences were aligned using MAFFT (Multiple Alignment using Fast Fourier Transform) web server tool. Alignment was carried out using 10 different set of alignment parameter values. After alignment the aligned file was used for constructing N-J phylogenetic tree using Clustal X2 tool. Phylogenetic analysis was performed keeping in mind the category to which the sequence belongs. Upon analysis it was observed that the clade containing the probable ancestor belongs remained constant in all cases of different alignment values. Non recombinant isolates, inter subtype recombinants, CRFs, URFs all followed different patterns of evolution. Non recombinant sequences were found geographically specific and subtype specific to some extent whereas, normal recombinants were subtype specific and less geographically specific. CRFs showed variation among the pattern of their evolution. At some instances the sequences occurred as sister taxa of non-recombinant or normal inter subtype recombinant sequences, while at some instances as sister taxa of other CRFs where they were geographically specific. Three CRFs existed as completely diverged sequences. URFs were four in number; two of them were Indian isolates of while other two were Japanese isolates. URFs were found to be totally geographically specific. Geography wise high rate of variation was observed in India and Japan as these two countries had sequences belonging to all of the above categories. Cameroon and South Africa have very large number isolates and a considerable amount of genetic variation among isolates but they lack URFs.
Źródło:
International Letters of Natural Sciences; 2014, 02
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of organic inputs on strength and stability of soil aggregates under rice-wheat rotation
Autorzy:
Das, B.
Chakraborty, D.
Singh, V.K.
Aggarwal, P.
Singh, R.
Dwivedi, B.S.
Powiązania:
https://bibliotekanauki.pl/articles/25472.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
tensile strength
stability
soil aggregate
rice
wheat
cereal crop rotation
Opis:
The study aims to elucidate the impact of organic inputs on strength and structural stability of aggregates in a sandy loam soil. Tensile strength, friability and water stability of aggregates, and the carbon contents in bulk soil and in large macro (>2 mm), small macro (0.25-2 mm), micro (0.053-0.25 mm) and silt+clay size (<0.053) aggregates were evaluated in soils from a long-term experiment with rice-wheat rotation at Modipuram, India, with different sources and amounts of organic C inputs as partial substitution of N fertilizer. Addition of organic substrates significantly improved soil organic C contents, but the type and source of inputs had different impacts. Tensile strength of aggregates decreased and friability increased through organic inputs, with a maximum effect under green gram residue (rice)-farmyard manure (wheat) substitution. Higher macroaggregates in the crop residue- and farmyard manure-treated soils resulted in a higher aggregate mean weight diameter, which also had higher soil organic C contents. The bulk soil organic C had a strong relation with the mean weight diameter of aggregates, but the soil organic C content in all aggregate fractions was not necessarily effective for aggregate stability. The soil organic C content in large macroaggregates (2-8 mm) had a significant positive effect on aggregate stability, although a reverse effect was observed for aggregates <0.25 mm. Partial substitution of nitrogen by organic substrates improved aggregate properties and the soil organic C content in bulk soil and aggregate fractions, although the relative effect varied with the source and amount of the organic inputs.
Źródło:
International Agrophysics; 2014, 28, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Studies on Advanced Sheet Explosive Formulations Based on 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and Hydroxyl Terminated Polybutadiene (HTPB), and Comparison with a RDX-based System
Autorzy:
Jangid, S. K.
Talawar, M. B.
Singh, M. K.
Nath, T.
Sinha, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/358055.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
hazardous materials
sheet explosive
explosive reactive armour (ERA)
CL-20
RDX
Opis:
The present investigation reports the use of 2,4,6,8,10,12-hexanitro2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) in sheet explosive formulations. In this study, hydroxyl terminated polybutadiene (HTPB) based sheet explosives were prepared incorporating the powerful explosive CL-20 as a partial replacement for hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX). The effects of incorporating CL-20 on the performance, sensitivity, thermal and mechanical properties of the sheet explosive compositions are reported. Sheet explosive formulation containing 80% of RDX and 20% of HTPB-binder was studied as control sample. HTPBbinder consisted of 12% HTPB, 2.9% dioctyl adipate (DOA) and 5.1% dioctyl phthalate (DOP). HTPB was cured with 4,4’-methylene diphenyl di-isocyanate (MDI) to form urethane linkages. The incorporation of 20% of CL-20 in place of RDX led to a remarkable increase in the velocity of detonation (VOD), of the order of 7680 m/s, and to better mechanical properties in terms of tensile strength (1.14 MPa) compared to the control formulation [RDX /HTPB-binder (80/20)]. The 20% CL-20 incorporated sheet explosive formulation also showed remarkable increases in impact and shock sensitivity. Thermal analysis of the sheet explosive compositions has also been carried out using differential scanning calorimetry (DSC).
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 1; 135-147
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity enhancement of metamaterial-based surface plasmon resonance biosensor for near infrared
Autorzy:
Pal, S.
Prajapati, Y. K.
Saini, J. P.
Singh, V.
Powiązania:
https://bibliotekanauki.pl/articles/173477.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metamaterials
sensor sensitivity
reflectance
evanescent field
Opis:
The present study investigates the angular response and sensitivity of a surface plasmon resonance biosensor with metamaterial, by taking the advantage of the remarkable property of metamaterials. The proposed biosensor numerically shows that silver with a metamaterial layer enhances the sensitivity. The thickness of metamaterial and silver layer has been optimized. On comparing these results with a conventional surface plasmon resonance biosensor, it is observed that the sensitivity of the proposed biosensor is improved by introducing the metamaterial. The proposed biosensor has a sensitivity 6.3124 times higher than that of the conventional surface plasmon resonance sensor.
Źródło:
Optica Applicata; 2016, 46, 1; 131-143
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of low-cost intervention (foamrubber) among wood carvers exposed to hand-arm vibration and noise
Autorzy:
Singh, A.K.
Meena, M.L.
Chaudhary, H.
Karmakar, S.
Powiązania:
https://bibliotekanauki.pl/articles/52811.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2019, 62, 203
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on biosynthesis of silver nanoparticles using Rhizopus sp. and its antibacterial efficacy on E. coli MDR strains
Autorzy:
Hiremath, J.
Rathod, V.
Ninganagouda, S.
Singh, D.
Prema, K.
Powiązania:
https://bibliotekanauki.pl/articles/11479.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
biosynthesis
silver nanoparticle
Rhizopus
antibacterial activity
Escherichia coli
multidrug resistance
nanotechnology
Opis:
Nanotechnology is a field that is burgeoning day by day, making an impact in all spheres of human life. Biological methods of synthesis have paved way for the “greener synthesis” of nanoparticles and these have proven to be better methods due to slower kinetics, they offer better manipulation and control over crystal growth and their stabilization. In this context we have investigated extracellular biosynthesis of silver nanoparticles (AgNPs) using cell-free extract of Rhizopus spp.. Formation of AgNPs was indicated by the change in the colour of the cellfree extract from yellow to dark brown under static condition after 48 hrs of incubation. Characterization of AgNPs was carried out by UV-Vis Spectroscopy which gave sharp plasmon resonance peak at 429 nm corresponding to spherical shaped nanoparticles. Transmission electron microscopy (TEM) micrograph showed formation of well-dispersed AgNPs in the range of 25-50 nm. Scanning electron microscopy (SEM) showed the particles to be uniformly dispersed without agglomeration with smooth morphology. EDS showed the presence of elemental silver at 3kev. X-ray diffraction (XRD)-spectrum of the AgNPs exhibited 2θ¸ values corresponding to nanocrystal. These biosynthesized AgNPs were used to study their antimicrobial activity against Multi-drug resistant (MDR) E. coli strains, by Agar diffusion method. Zone of inhibition was measured. Synthesis of nanosized particles with antibacterial properties, which are called "nanoantibiotics", is of great interest in the development of new pharmaceutical products.
Źródło:
International Letters of Natural Sciences; 2014, 18
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural convection in a hydrodynamically and thermally anisotropic non-rectangular porous cavity: effect of internal heat generation/absorption
Autorzy:
Chandran, P.
Sacheti, N. C.
Bhadauria, B. S.
Singh, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/264468.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja naturalna
materiały porowate
przepuszczalność
dyfuzyjność cieplna
źródło ciepła
natural convection
trapezoidal cavity
porous medium
permeability
thermal diffusivity
Darcy's law
heat source/sink
Opis:
Laminar natural convection in a trapezoidal porous vertical cavity has been investigated in this work. It is assumed that the porous enclosure is filled up with a permeable material subject to hydrodynamic and thermal anisotropy, the flow being governed by the Darcy law as applicable to a non-isotropic medium. It is further assumed that (i) there is heating at the left vertical wall and cooling at the right wall of the enclosure and (ii) the flow domain is subject to the presence of heat source or heat sink. The partial differential equations governing the resulting free convection have been solved numerically in the non-dimensional forms. There arises a number of parameters relating to buoyancy, internal heating, cavity aspect ratio and inclination of the upper surface to the horizontal. The influence of these parameters has been illustrated and analyzed through contours of streamlines and isotherms. We have also discussed the role of internal heating as well as anisotropy on the heat transfer characteristics.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 595-609
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
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

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