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Tytuł:
Activity pattern and food habits of Grizzled Giant Squirrel (Ratufa macroura) in Srivilliputhur Grizzled Squirrel Wildlife Sanctuary, Tamil Nadu, Southern India
Autorzy:
Babu Rao, G.
Nagarajan, R.
Saravanan, M.
Baskaran, N.
Powiązania:
https://bibliotekanauki.pl/articles/11307.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Activity pattern and food habits of Grizzled Giant Squirrel were investigated in Srivilliputhur Grizzled Giant Squirrel Wildlife Sanctuary from December 2011 to March 2012. Focal animal sampling method was used to record the activity pattern and food habits. Sampling was done in three different habitats viz., Private land, Reserve forest and Temple land. Feeding was the dominant activity accounting for 35.4% of the activity period. Bimodal feeding pattern was observed in Squirrels, the observations were made from early morning hours to till (0600-1800) late evening hours. The Squirrels feed upon 23 plant species; among them 11 were trees species, 10 climbers and 2 shrubs. Seven types of plant parts were used by Squirrels. Leaf consumption was high (38%) followed by fruit (24%). The high consumption of leaves was due to easy availability of leaves and limited availability of other plant parts. Squirrel‟s invasion into Private Land and Temple Land was observed which can be attributed to abundance and easy availability of food plants, canopy continuity and less predatory pressure.
Źródło:
International Letters of Natural Sciences; 2015, 05
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Creep Behavior of Composite Solid Propellants Using the Kelvin-Voigt Model
Autorzy:
Bihari, B. K.
Rao, N. P. N.
Gupta, M.
Murthy, K. P. S.
Powiązania:
https://bibliotekanauki.pl/articles/358395.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
mechanical properties
viscoelasticity
propellant
creep
DMA
Opis:
A Kelvin-Voigt model consisting of a spring and a dashpot in parallel was applied for the viscoelastic characterization of solid rocket propellants. Suitable values of spring constants and damping coefficients were employed by a least squares fit of the errors to generate creep curves using a Dynamic Mechanical Analyzer (DMA) for composite solid propellants. Three different composite propellant formulations based on HTPB/AP/Al having burning rates of 5 mm/s, 15 mm/s and 20 mm/s were tested under different stress levels varying from 0.1 MPa to 3 MPa and at different temperatures varying from 35 °C to 85 °C. Creep behavior with recovery was studied and analyzed to evaluate the viscoelastic properties. The change in spring constants, representing elastic deformation, was very small compared to the damping coefficients for the propellants studied. For a typical propellant formulation, when the stress level was increased, the spring and damping coefficient both increased significantly whereas for an increase in temperature, they remained nearly constant. However, the ratio E/η was observed to be constant and independent of stress level. It was also observed that the variation of E and η varied linearly with increase in stress whereas their ratio showed a logarithmic variation. A mathematical correlation was developed to evaluate the viscoelastic properties during creep of composite propellants.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 3; 742-756
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Dynamics of the Forest Graph Operator
Autorzy:
Dara, Suresh
Hegde, S.M.
Deva, Venkateshwarlu
Rao, S.B.
Zaslavsky, Thomas
Powiązania:
https://bibliotekanauki.pl/articles/31340605.pdf
Data publikacji:
2016-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
forest graph operator
graph dynamics
Opis:
In 1966, Cummins introduced the “tree graph”: the tree graph \( \textbf{T} (G) \) of a graph \( G \) (possibly infinite) has all its spanning trees as vertices, and distinct such trees correspond to adjacent vertices if they differ in just one edge, i.e., two spanning trees \( T_1 \) and \( T_2 \) are adjacent if \( T_2 = T_1 − e + f \) for some edges \( e \in T_1 \) and \( f \notin T_1 \). The tree graph of a connected graph need not be connected. To obviate this difficulty we define the “forest graph”: let \( G \) be a labeled graph of order \( \alpha \), finite or infinite, and let \( \mathfrak{N}(G) \) be the set of all labeled maximal forests of \( G \). The forest graph of \( G \), denoted by \( \textbf{F} (G) \), is the graph with vertex set \( \mathfrak{N}(G) \) in which two maximal forests \( F_1 \), \( F_2 \) of \( G \) form an edge if and only if they differ exactly by one edge, i.e., \( F_2 = F_1 − e + f \) for some edges \( e \in F_1 \) and \( f \notin F_1 \). Using the theory of cardinal numbers, Zorn’s lemma, transfinite induction, the axiom of choice and the well-ordering principle, we determine the F-convergence, F-divergence, F-depth and F-stability of any graph \( G \). In particular it is shown that a graph \( G \) (finite or infinite) is F-convergent if and only if \( G \) has at most one cycle of length 3. The F-stable graphs are precisely \( K_3 \) and \( K_1 \). The F-depth of any graph \( G \) different from \( K_3 \) and \( K_1 \) is finite. We also determine various parameters of \( \mathbf{F} (G) \) for an infinite graph \( G \), including the number, order, size, and degree of its components.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 4; 899-913
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Barium Strontium Bismuth Niobate Layered Perovskites: Dielectric, Impedance and Electrical Modulus Characteristics
Autorzy:
Dasari, M.
Sambasiva Rao, K.
Murali Krishna, P.
Gopala Krishna, G.
Powiązania:
https://bibliotekanauki.pl/articles/1505356.pdf
Data publikacji:
2011-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.-s
77.84.Ek
72.80.Ng
Opis:
$SrBi_2Nb_2O_9$ (SBN) is a bismuth layered perovskite compound, due to its relatively high Curie temperature, has potential application as high ceramic transducer. Also, it is an attractive ferroelectric material that is being considered in non-volatile random access memory cells. Present article describes preparation, dielectric, impedance and modulus characteristics. Temperature and frequency dependence of dielectric permittivity, impedance and electric modulus of barium strontium bismuth niobate ($Ba_{0.1}Sr_{0.9}Bi_2Nb_2O_9$, BSBN) have been studied in the range of 35-590°C and 45 Hz-5 MHz, respectively. The structural analysis of compound revealed orthorhombic at room temperature. Complex impedance Cole-Cole plots are used to interpret the relaxation mechanism. These plots shows the relaxation behavior as non-Debye type. By using the Cole-Cole plots grain and grain boundary contributions towards conductivity have been estimated. From electrical modulus formalism polarization and conductivity relaxation behavior in BSBN have been discussed. DC and AC conductivity measurements have been performed on BSBN.
Źródło:
Acta Physica Polonica A; 2011, 119, 3; 387-394
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a Method for Characterization of the Fibre Length of Long Staple Carbon Fibres Based on Image Analysis
Opracowanie metody dla charakteryzacji długości węglowych włókien ciętych o dużej długości
Autorzy:
Hengstermann, M.
Bardl, G.
Rao, H.
Abdkader, A.
Badrul Hasan, M. M.
Cherif, C.
Powiązania:
https://bibliotekanauki.pl/articles/233180.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
carbon fibre
fibrogram
span length diagram
staple length
włókno węglowe
Opis:
For the manufacturing of load-bearing carbon fibre reinforced plastics (CFRP) made from staple carbon fibres (CF) , statements of the CF fibre length in the composite are essential. However, no suitable fibre length measuring method is currently available for long staple CF over 60 mm. The aim of this study is the development of an effective method for characterization of the fibre length distribution of long staple CF. For this method, a fibre beard specimen is extracted from a sliver manufactured from 80 mm staple CF, which is then scanned. Greyscale values densities (GD) of the individual length classes are determined from the scanned images, which correspond to the number of fibres per length class. From the proportion of all length classes, a span length diagram and staple fibre length diagram can be compiled. The results show the good potential of the method developed for the fibre length measurement of long staple CF.
Dla wytwarzania kompozytów ze wzmocnieniem włókien węglowych bardzo ważna jest znajomość rozkładu długości tych włókien. Niestety, jak dotychczas nie istniały odpowiednie metody pomiarowe pozwalające charakteryzować włókna odcinkowe o długościach powyżej 60 mm. Celem pracy była analiza istniejących metod pomiarowych oraz opracowanie metody, która umożliwiłaby satysfakcjonujące rozwiązanie tego zagadnienia. Zostały przedstawione zasady działania tej metody oraz uzyskana dokładność pomiarów.
Źródło:
Fibres & Textiles in Eastern Europe; 2016, 4 (118); 39-44
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ammonium Dodecahydrododecaborate (NH4)2[B12H12]: Hydrogen and Boron Rich Fuel for Jet Propulsion Engines
Autorzy:
Jadhav, Pandurang M.
Patil, Jay
Prasanth, Hima
Rao, Gururaja
Powiązania:
https://bibliotekanauki.pl/articles/27788219.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
jet propulsion
boranes
boron
combustion
specific impulse
Opis:
There is dire need for the exploration of boron (B) substitution in jet propulsion engines for improving their combustion characteristics. In this regard, ammonium dodecahydrododecaborate (NH4)2[B12H12] has been synthesized, characterized and evaluated for its propulsion characteristics. This hydrogen and boron-rich entity was found to be a potential candidate for future applications in propulsion technology.
Źródło:
Central European Journal of Energetic Materials; 2022, 19, 2; 158--167
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A piliminary survey of House Sparrow (Passer domesticus) in Ramakrishna Beach Road, Vishakhapatnam (Vizag), Andhra Pradesh
Autorzy:
Laxmi Narayana, B.
Vasudeva Rao, V.
Sandeep, M.
Surender, G.
Ramaligeswara Rao, A.V.L.N.
Powiązania:
https://bibliotekanauki.pl/articles/11018.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
We studied the population records of House Sparrow Passer domesticus 16th to 20th December 2011 during winter in Ramakrishna Beach Road Vishakhapatnam town, Andhra Pradesh. The ecological density of House Sparrow was investigated using fixed width transects. A total of 189 House sparrows were recorded. The present study shows that a notable population of House Sparrow in Beach Road.
Źródło:
International Letters of Natural Sciences; 2015, 04
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Object-parameter approaches to predicting unknown data in an incomplete fuzzy soft set
Autorzy:
Liu, Y.
Qin, K.
Rao, C.
Alhaji Mahamadu, M.
Powiązania:
https://bibliotekanauki.pl/articles/331019.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fuzzy soft set
incomplete fuzzy soft set
object parameter approach
prediction
similarity measures
zbiór rozmyty
podejście obiektowe
miara podobieństwa
Opis:
The research on incomplete fuzzy soft sets is an integral part of the research on fuzzy soft sets and has been initiated recently. In this work, we first point out that an existing approach to predicting unknown data in an incomplete fuzzy soft set suffers from some limitations and then we propose an improved method. The hidden information between both objects and parameters revealed in our approach is more comprehensive. Furthermore, based on the similarity measures of fuzzy sets, a new adjustable object-parameter approach is proposed to predict unknown data in incomplete fuzzy soft sets. Data predicting converts an incomplete fuzzy soft set into a complete one, which makes the fuzzy soft set applicable not only to decision making but also to other areas. The compared results elaborated through rate exchange data sets illustrate that both our improved approach and the new adjustable object-parameter one outperform the existing method with respect to forecasting accuracy.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 1; 157-167
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Reconfigurable Split Ring Antenna for LTE And WiMAX Applications
Autorzy:
Madhav, B. T. P.
Nadh, B.
Anilkumar, T.
Pardhasaradhi, P.
Rao, M. C.
Lakshman, P.
Powiązania:
https://bibliotekanauki.pl/articles/226800.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PIN diode
WiMAX
LTE 2500
split ring antenna
BAR64-02V
Opis:
This paper presents frequency reconfigurable dual band antenna for WiMAX and LTE 2500 band applications using four PIN diode switches. The antenna is compact in size with dimensions of 30 x 30 x 0.8 mm3 and designed on FR-4 dielectric substrate with a partial ground plane. The fabricated antenna operates in the frequency range of LTE and WiMAX (2.5-2.69 GHz and 3.4-3.6 GHz) respectively. The frequencies can be controlled by using PIN diodes and antenna attained the gain ranging of 3.34-4.46 dBi. This designed antenna resonating at 2.52 and 3.49 GHz when the PIN diodes are in ON state and resonating at 2.68 and 3.58 GHz when PIN diodes are in OFF state. The proposed antenna has bidirectional radiation at upper frequency bands and unidirectional at lower frequency bands. The proposed split ring structured antenna has the radiation efficiency of 94.12% at 2.52 GHz and 90.34% at 3.49 GHz in ON state. Antenna providing good agreement between the measured (Antenna measurement setup with VNA) and simulated results (Ansys-HFSS).
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 2; 255-260
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of thermal modulation on double diffusive convection in the presence of applied magnetic field and internal heat source
Autorzy:
Manjula, S. H.
Suresh, P.
Rao, M. G.
Powiązania:
https://bibliotekanauki.pl/articles/1839901.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
analiza nieliniowa
płyn newtonowski
konwekcja
thermal modulation
weak nonlinear analysis
internal heating
newtonian fluid
double diffusive convection
Opis:
The investigation of thermal modulation on double-diffusive stationary convection in the presence of an applied magnetic field and internal heating is carried out. A weakly nonlinear stability analysis has been performed using the finite-amplitude Ginzburg-Landau model. This finite amplitude of convection is obtained at the third order of the system. The study considers three different forms of temperature modulations. OPM-out of phase modulation, LBMO-lower boundary modulation, IPM-in phase modulation. The finite-amplitude is a function of amplitude ,Tδ frequency ω and the phase differenceθ . The effects of Tδ and ω on heat/mass transports have been analyzed and depicted graphically. The study shows that heat/mass transports can be controlled effectively by thermal modulation. Further, it is found that the internal Rayleigh number iR enhances heat transfer and reduces the mass transfer in the system.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 1; 135-155
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global scenario of Acrocarpus fraxinifolius Wight and Arn. - A future tree of Agro forestry
Autorzy:
Mishra, G.
Pandey, A.K.
Arunachalam, M.K.
Rao, S.
Powiązania:
https://bibliotekanauki.pl/articles/11909.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Acrocarpus fraxinifolius portrait one among the mainstay of agro forestry in Asian tropics. The lofty tree fortified a substantial impact in every horizon of life. The evergreen, deciduous tree of Fabaceae family stands tall about 30-60 m endowed with unique properties which idiosyncrasies it in the plant kingdom. Surpassing the adverse climatic conditions, A. fraxinifolius serves as a shade tree for tea and coffee plantation and epitomises as a multipurpose avenue tree culminating to the culture of agro forestry. Mundani in bloom is a spectacular appearance bestowed with scarlet crimson red flowers attracting infinite migratory birds and insects. The ancestral gene with indelible memory gravitate this extraordinary majestic tree to aestivate and adapt to strongest survive.
Źródło:
International Letters of Natural Sciences; 2015, 03
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative performance with different versions of low heat rejection combustion chambers with crude rice bran oil
Porównanie osiągów różnych wersji komór spalania o małych stratach ciepła przy wykorzystaniu surowego oleju roślinnego z otrąb ryżowych
Autorzy:
Murali, K. M. V. S.
Rao, N. D. P.
Prasad, B. A.
Murthy, P. V. K.
Powiązania:
https://bibliotekanauki.pl/articles/140033.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alternate fuels
vegetable oil
biodiesel
LHR engine
fuel performance
exhaust emissions
combustion characteristics
paliwa alternatywne
olej roślinny
silnik o małych stratach ciepła
wydajność paliwa
emisja spalin
charakterystyka spalania
Opis:
It has been found that the vegetable oils are promising substitute, because of their properties are similar to those of diesel fuel and they are renewable and can be easily produced. However, drawbacks associated with crude vegetable oils are high viscosity, low volatility call for low heat rejection combustion chamber, with its significance characteristics of higher operating temperature, maximum heat release, and ability to handle lower calorific value (CV) fuel etc. Experiments were carried out to evaluate the performance of an engine consisting of different low heat rejection (LHR) combustion chambers such as ceramic coated cylinder head-LHR-1, air gap insulated piston with superni (an alloy of nickel) crown and air gap insulated liner with superni insert – LHR-2; and ceramic coated cylinder head, air gap insulated piston and air gap insulated liner – LHR-3 with normal temperature condition of crude rice bran oil (CRBO) with varied injector opening pressure. Performance parameters (brake thermal efficiency, brake specific energy consumption, exhaust gas temperature, coolant load, and volumetric efficiency) and exhaust emissions [smoke levels and oxides of nitrogen [NOx]] were determined at various values of brake mean effective pressure of the engine. Combustion characteristics [peak pressure, time of occurrence of peak pressure, maximum rate of pressure rise] were determined at full load operation of the engine. Conventional engine (CE) showed compatible performance and LHR combustion chambers showed improved performance at recommended injection timing of 27 degrees bTDC and recommend injector opening pressure of 190 bar with CRBO operation, when compared with CE with pure diesel operation. Peak brake thermal efficiency increased relatively by 7%, brake specific energy consumption at full load operation decreased relatively by 3.5%, smoke levels at full load decreased relatively by 11% and NOx levels increased relatively by 58% with LHR-3 combustion chamber with CRBO at an injector opening pressure of 190 bar when compared with pure diesel operation on CE.
Jak wiadomo, oleje roślinne są obiecującym substytutem paliw ropopochodnych, ponieważ ich właściwości są podobne do oleju dieslowskiego, są odnawialne i łatwe do wyprodukowania. Niemniej, surowe oleje roślinne wykazują wady, takie jak wysoka lepkość i mała lotność, co wymaga komory spalania o małych stratach ciepła, której istotnymi cechami są m.in. wyższa temperatura robocza, maksymalne wydzielanie ciepła i zdolność do wykorzystania paliwa o mniejszej wartości kalorycznej (CV). Przeprowadzono eksperymenty mające na celu ocenę osiągów silnika z różnymi komorami spalania o małych stratach ciepła (LHR), takich jak głowica cylindra o pokryciu ceramicznym (LHR-1), tłok izolowany szczeliną powietrzną z denkiem ze stopu Superni (superstop niklu) i tuleją cylindra z wkładką z Superni izolowaną szczeliną powietrzną (LHR-2) oraz głowica cylindra z pokryciem ceramicznym, tłok i tuleja cylindra izolowane szczelinami powietrznymi (LHR-3). Badania prowadzono przy normalnej temperaturze oleju roślinnego (surowy olej z otrąb ryżowych, CRBO) i zmiennym ciśnieniu w otworze wtryskiwacza. Parametry osiagów silnika (użyteczna sprawność termiczna, użyteczny współczynnik zużycia energii, temperatura gazu wydychanego, obciążenie obiegiem chłodziwa i współczynnik napełnienia) oraz emisje wydechowe [poziomy dymu i tlenków azotu, NOx] zostały wyznaczone przy różnych wartościach średniego użytecznego ciśnienia w silniku. Charakterystyki spalania [ciśnienie szczytowe, czas występowania ciśnienia szczytowego, maksymalna szybkość wzrostu ciśnienia] zostały wyznaczone w warunkach pracy silnika z pełnym obciążeniem. W porównaniu z silnikiem napędzanym olejem diesla, silnik konwencjonalny (CE) wykazał podobne osiągi przy pracy z olejem roślinnym (CRBO), a w komorach spalania o małych stratach ciepła (LHR) uzyskano lepsze osiągi przy zalecanym kącie wtrysku 27b stopni TDC (przed górnym punktem zwrotnym) i zalecanym ciśnieniu w otworze wtryskiwacza równym 190 bar. Szczytowa użyteczna sprawność cieplna wzrosła relatywnie o 7%, użyteczny współczynnik zużycia energii zmalał o 3,5% przy pracy z pełnym obciążeniem, poziomy dymu przy pełnym obciążeniu zmalały o 11%, a poziom tlenków NOx wzrósł relatywnie o 58% w przypadku komory spalania typu LHR-3 napędzanej olejem roślinnym CBRO przy ciśnieniu w otworze wtryskiwacza 190 bar, w porównaniu z parametrami uzyskanymi przy pracy z czystym olejem diesla.
Źródło:
Archive of Mechanical Engineering; 2014, LXI, 4; 627-651
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Rock Properties on Wear of M and SR Grade Rubber with Varying Normal Load and Sliding Speed
Autorzy:
Pal, S. K.
Rao, K. U. M.
Kumar, P. S.
Rajasekar, R.
Powiązania:
https://bibliotekanauki.pl/articles/356996.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rock
rubber
wear
shear strength
surface roughness
Opis:
Rubbers are interesting materials and are extensively used in many mining industries for material transportation. Wear of rubber is a very complex phenomenon to understand. The present study aims to explain the influence of rock properties on wear of M and SR grade rubber used in top cover of conveyor belts. Extensive laboratory experiments were conducted under four combinations of normal load and sliding speed. The wear of both the rubber types were analyzed based on the rock properties like shear strength, abrasivity index and fractal dimension. A fully instrumented testing set up was used to study the wear of rubber samples under different operating conditions. In general, wear was higher for M grade rubber compared to SR grade rubber. Increase in shear strength of rocks depicts decreasing trend for the wear of M and SR grade rubber at lower load conditions. Moreover, a higher load combination displays no definite trend in both the rubbers. The strong correlation between the wear of rubber and frictional power for all rubber-rock combinations has given rise to the parameter A, which reflects the relative compatibility between the rubber and rock. Increase of Cerchar’s Abrasivity Index of rocks shows gradual enhancement in wear for M grade rubber in all the load and speed combinations whereas, it fails in SR grade rubber due to its higher strength. The wear of rubber tends to decrease marginally with the surface roughness of rocks at highest normal load and sliding speed in M grade rubber. However, the wear of M and SR grade rubber is influenced by the surface roughness of rocks.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1787-1793
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical investigation of stresses induced at blade mounting locations in steam turbine rotor system
Autorzy:
Prasad, D. K.
Ramana, K. V.
Rao, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/947280.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
tarcza wirnika
wirnik turbiny parowej
naprężenie styczne
rotor disc
radial stress
tangential stress
steam turbine rotors
Opis:
One of the most common incipient losses of integrity in mechanical structures is the development and propagation of cracks. Especially in rotating members like steam turbine rotors etc. cracks, because of their potential, cause catastrophic failures and are a grave threat to an uninterrupted operation and performance. A crack may propagate from some small imperfections on the surface of the body or inside of the material and it is most likely to appear in correspondence to high stress concentration. Crack propagation path is generally determined by the direction of maximum stress or by the minimum material strength. Hence determination of stresses induced has been the focus of attention for many researchers. In the present work, development of a mathematical model to determine the stresses induced in a rotating disc of varying thickness is studied. This model is applied to a steam turbine rotor disc to determine the induced stresses and radial deflection. The mathematical modeling results are validated with the results obtained using Ansys package. The results of the present study will be useful in diagnosing the location and magnitude of maximum stress induced in the turbine rotor disc and stress intensity factor due to the presence of crack.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 295-307
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 28

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