Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Kumar, S." wg kryterium: Autor


Tytuł:
Flood risk zoning of Satluj River Basin, Himachal Pradesh, India
Autorzy:
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/11273.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Increasing intensity and frequency of rainfall coupled with gradual retreating of glaciers due to climate change in Himalayan region likely to increase the risk of floods. A better understanding of risk zones which are vulnerable to flood disasters can be evolved from the detailed studies on slope, geomorphology and land use/ land cover pattern. Information of these parameters is an important input for the identification of vulnerable areas. Flood risk maps provide useful information about places that may be at risk from flooding. It offers a cost-effective solution for planning, management and mitigation strategies in risky areas. Traditional methods of flood risk mapping are based on ground surveys and aerial observations, but when the phenomenon is widespread, such methods are time consuming and expensive. The possible combination of DEM and other maps of area using an overlay operation method within the Geographical Information System (GIS) platform can lead to derivation and the understanding of spatial association between various parameters which could be used to predict flood risk zones. The study area i.e. Satluj River Basin has been broadly divided into five risk zones viz., very low, low, moderate, high and very high which helped to differentiate between areas that are at risk of different intensities of flood. The very high flood risk zone covers only 3.25 % of total study area, while the very low risk zone covers 13.63 %. The area falls within the very high and high risk constitutes 9.52 % of total basin area. Domain of moderate risk covers an area of 30.66 %. But the maximum area of river basin is constituted by low risk zone i.e. 46.19 %. Identification of such zones will help in timely adopting of mitigation and adaptation measures. Preparation of flood risk zoning maps also helps in regulating indiscriminate and unplanned land use practices in risky areas.
Źródło:
International Letters of Natural Sciences; 2015, 40
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trend analysis of flood peaks in lower reaches of Satluj River, Himachal Pradesh, India
Autorzy:
Kumar, S.
Santosh, ---
Powiązania:
https://bibliotekanauki.pl/articles/970628.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
flood peaks
mann-kendall test
satluj river basin
regression
trend analysis.
Opis:
Climate change arising from anthropogenic driven emissions of greenhouse gases has emerged as one of the most important environmental issues in the last two decades. One of the most significant potential consequences of climate change may be alteration in regional hydrological cycle and river flow regimes. Increased temperature is expected to increase the peak flows in snowfed rivers of Himalayas. The changing pattern of regional temperature on flood peaks deserves urgent and systematic attention over a basin which provides an insight view of historical trends. Lower reaches of Satluj River is selected for the present study. Testing the significance of observed trends in flood peaks has received a great attention recently, especially in connection with climate change. The data series available was 48 years (1967-2010). The records were subjected to trend analysis by using both non-parametric (Mann-Kendall test) and parametric (linear regression analysis) procedures. For better understanding of the observed trends, flood peaks were computed into standardised flood peak indices (SFPI). These standardised data series were plotted against time and the linear trends observed were represented graphically. The analysis of flood peaks at different observation stations in lower reaches of Satluj River showed a large variability in the trends and magnitudes. The trend analysis results of flood peaks and gauge heights indicate that the flood peaks at all sites i.e. Rampur, Suni and Kasol show increasing but statistically insignificant trends. The trends in gauge height at all sites are also showing increasing trend but Kasol is statistically significant at 95% confidence level. The fast melting of glaciers, incessant monsoon rainfall and the synchronisation of the discharge peaks are the main causes of river floods. The past flood peaks will help us to observe the frequency of occurrence of floods in certain region and to determine whether the flood peaks in the past have been same with that of the present or whether there is any deviation in the trend in relation to climate change. Such studies will help in designing mitigation and adaptation strategies towards extreme hydrological events.
Źródło:
International Letters of Natural Sciences; 2015, 46
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructural considerations on SH-wave propagation in a piezoelectric layered structure
Autorzy:
Goyal, R.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/280348.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
SH-wave
piezoelectricity
couple stress
characteristic length
Opis:
Shear wave based acoustic devices are being used in gaseous and liquid environments because of their high-sensitivity. The theoretical study of horizontally polarized shear (SH) waves in a layered structure consisting of a piezoelectric ceramic of P ZT − 5H or BaT iO3 material overlying a couple stress substrate is presented in this paper. The considered substrate is supposed to be exhibiting microstructural properties. The closed form expression of dispersion relations are derived analytically for electrically open and short conditions. The effects of internal microstructures of the couple stress substrate, thickness of P ZT − 5H or BaT iO3 ceramic, piezoelectric and dielectric constants are illustrated graphically on the phase velocity of the piezoelectric layer under electrically open and short conditions.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 4; 993-1004
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controllability of semilinear systems with fixed delay in control
Autorzy:
Kumar, S.
Sukavanam, N.
Powiązania:
https://bibliotekanauki.pl/articles/952777.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
first order delay system
mild solution
fixed point
exact controllability
Opis:
In this paper, different sufficient conditions for exact controllability of semilinear systems with a single constant point delay in control are established in infinite dimensional space. The existence and uniqueness of mild solution is also proved under suitable assumptions. In particular, local Lipschitz continuity of a nonlinear function is used. To illustrate the developed theory some examples are given.
Źródło:
Opuscula Mathematica; 2015, 35, 1; 71-83
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of UPFC for enhancement of voltage profile and minimization of losses using Fast Voltage Stability Index (FVSI)
Autorzy:
Kumar, S.
Renuga, P.
Powiązania:
https://bibliotekanauki.pl/articles/140514.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flexible AC transmission system (FACTS)
real and reactive power
Unified Power Flow Controller (UPFC)
Bacterial Foraging (BF) algorithm
Opis:
Transmission line loss minimization in a power system is an important research issue and it can be achieved by means of reactive power compensation. The unscheduled increment of load in a power system has driven the system to experience stressed conditions. This phenomenon has also led to voltage profile depreciation below the acceptable secure limit. The significance and use of Flexible AC Transmission System (FACTS) devices and capacitor placement is in order to alleviate the voltage profile decay problem. The optimal value of compensating devices equires proper optimization technique, able to search the optimal solution with less computational burden. This paper presents a technique to provide simultaneous or individual controls of basic system parameter like transmission voltage, impedance and phase angle, thereby controlling the transmitted power using Unified Power Flow Controller (UPFC) based on Bacterial Foraging (BF) algorithm. Voltage stability level of the system is defined on the Fast Voltage Stability Index (FVSI) of the lines. The IEEE 14-bus system is used as the test system to demonstrate the applicability and efficiency of the proposed system. The test result showed that the ocation of UPFC improves the voltage profile and also minimize the real power loss.
Źródło:
Archives of Electrical Engineering; 2012, 61, 2; 239-250
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Muscular Activity Involved in the Use of Two Different Types of Computer Mouse
Autorzy:
Kumar, R.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/90400.pdf
Data publikacji:
2008
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
muscular activity
EMG
computer mouse
Opis:
Two types of computer input devices, a conventional mouse and a roller bar one, were studied in terms of muscular activitiy in m. trapezius dexter, m. deltoideus anterior dexter and m. extensor digitorum dexter, and comfort rating. Fifteen university students and employees participated in this study. The order of the devices was random. While a task was performed, electromyography (EMG) data were recorded for each test. Muscular activity was found to be significantly lower for the roller bar mouse than for the conventional one. Comfort rating indicated there was a significant difference in moving a cursor with the conventional mouse compared to the roller bar one. It is concluded that a roller bar mouse allowed the subjects to work closer to the body compared to the conventional one, thus the former can be recommended as a general means of reducing upper extremity musculoskeletal disorders.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2008, 14, 3; 305-311
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Ergonomic Risk Assessment Output in Four Sawmill Jobs
Autorzy:
Jones, T.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/90305.pdf
Data publikacji:
2010
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
physical ergonomics
exposure assessment
musculoskeletal risk assessment
job analysis
prevention and control
Opis:
The objectives of this study were to examine the agreement between 5 ergonomic risk assessment methods calculated on the basis of quantitative exposure measures and to examine the ability of the methods to correctly classify 4 at risk jobs. Surface electromyography and electrogoniometry were used to record the physical exposures of 87 sawmill workers performing 4 repetitive jobs. Five ergonomic risk assessment tools (rapid upper limb assessment [RULA], rapid entire body assessment [REBA], American conference of governmental industrial hygienist’s threshold limit value for mono-task hand work [ACGIH TLV], strain index [SI], and concise exposure index [OCRA]) were calculated. Dichotomization of risk to no risk and at risk resulted in high agreement between methods. Percentage of perfect agreement between methods when 3 levels of risk were considered was moderate and varied by job. Of the methods examined, the RULA and SI were best (correct classification rates of 99 and 97% respectively). The quantitative ACGIH-TLV for mono-task hand work and Borg scale were worst (misclassification rates of 86 and 28% respectively).
Źródło:
International Journal of Occupational Safety and Ergonomics; 2010, 16, 1; 105-111
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomechanical Loads and Subjective Stress Exposure to Lumber Graders in Sawmill Industry
Autorzy:
Jones, T.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/90791.pdf
Data publikacji:
2011
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
job analysis
lumber graders
wood product manufacturing
repetitive strain
upper extremity
physical and psychophysical stress
Opis:
The aim of this study was to determine biomechanical loads and subjective stresses on lumber graders and associated morbidity in a high risk and repetitive sawmill occupation. The exposures of all 29 male sawmill worker volunteers were recorded. Motion and posture were studied with electrogoniometers, muscle loads were recorded with surface electromyography, and psychophysical stresses were assessed with subjective responses. Fifty-nine percent of the participants reported greater than moderate discomfort in their taskdominant upper extremity. Job performance required an average range of motion of 44º, 21º, and 52º in flexion/extension, radial/ulnar deviations, and pronation/supination respectively. It also required an average of 9% maximum voluntary contraction force and was repeated an average of 34 times/min. This repetitive exertion over an 8-h shift was deemed to be a significant risk factor associated with prevalent upper extremity morbidity.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2011, 17, 1; 87-97
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion of Rayleigh Waves in a Microstructural Couple Stress Substrate Loaded with Liquid Layer Under the Effects of Gravity
Autorzy:
Sharma, V.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/947783.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
couple stress theory
Rayleigh waves
gravity
characteristic length
liquid loading
Opis:
Bone loss is one of the serious health issues in bedridden patients or young generation due to lack of physical activities. Mechanical forces are exerted on the bones through ground reaction forces, liquid loadings and by other contraction activities of the muscles. We are assuming an isotropic half-space with mechanical properties equivalent to that of bone exhibiting microstructures. Consistent couple stress theory introduces an additional material parameter called characteristic length which accounts for inner microstructure of the material. Dispersion relations for leaky Rayleigh waves are derived by considering a model consisting of couple stress half space under the effects of gravity and loaded with inviscid liquid layer of finite thickness or a liquid half space. Impact of the gravity, liquid loadings and microstructures of the material are investigated on propagation of leaky Rayleigh type waves. Phase velocity of leaky Rayleigh waves is studied for five different values of characteristic length parameter which are of the order of internal cell size of the considered material. Variations in phase velocity of leaky Rayleigh waves are also studied under the effect of gravity parameter and thickness of liquid loadings.
Źródło:
Archives of Acoustics; 2018, 43, 1; 11-20
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion of SH waves in a viscoelastic layer imperfectly bonded with a couple stress substrate
Autorzy:
Sharma, V.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/949130.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
SH waves
couple stress theory
imperfect bonding
characteristic length
viscoelasticity
Opis:
The paper deals with propagation of SH waves in a viscoelastic layer over a couple stress substrate with imperfect bonding at the interface. A dispersion equation of SH waves in a viscoelastic layer overlying the couple stress substrate with an imperfect interface between them has been obtained. Dispersion equations for propagation of SH waves with perfectly bonded interface and slippage interface between two media are also obtained as particular cases. Effects of the degree of imperfectness of the interface are studied on the phase velocity of SH waves. The dispersion curves are plotted and the effects of material properties of both couple stress substrate and viscoelastic layer are studied. The effects of internal microstructures of the couple stress substrate in terms of characteristic length of the material are presented. The effects of heterogeneity, friction parameter and thickness of the viscoelastic layer are also studied on the propagation of SH waves.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 535-546
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of liquid loadings on lamb waves in context of size dependent couple stress theory
Autorzy:
Sharma, V.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/949331.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
couple stress
characteristic length
Lamb waves
elastic waves
liquid loadings
Opis:
For understanding the effects of an internal microstructure, generalised microcontinuum theories with additional microstructural parameters are developed. One such a parameter, called the characteristic length of the material comparable with the internal cell size of the material is involved in the couple stress theory. The problem of propagation of Lamb waves in a plate with an internal microstructure and loaded with an inviscid liquid on both sides is studied using the couple stress theory. The dispersion equation of Lamb waves with the liquid loadings is derived. The impact of the liquid loadings is studied on the propagation of Lamb waves. The effect of the characteristic length is also studied on the phase velocity of Lamb waves in the plate for various modes in the presence of liquid loadings.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 925-934
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and characterization of laser welded incoloy 800 HT joints
Autorzy:
Arun Kumar, S.
Paulraj, S.
Powiązania:
https://bibliotekanauki.pl/articles/102190.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
incoloy 800 HT
laser welding
modeling and simulation
mechanical and metallurgical characteristics
Opis:
This study aims at finding the effect of laser welding speed on incoloy 800 HT. This alloy is one of the potential materials for Generation IV nuclear plants. Laser welding has several advantages over arc welding such as low fusion zone, low heat input and concentrated heat intensity. Three different welding speeds were chosen and CO2 laser welding was performed. 2D modeling and simulation were done using ANSYS 15 to find out the temperature distribution at different welding speeds and it was found that an increase in the welding speed decreased the temperature. Mechanical properties such as tensile strength, toughness and hardness were evaluated. The effect of welding speed on metallurgical characteristics was studied using optical microscopy (OM), Scanning Electron Microscopy (SEM) with EDS, X-Ray Diffraction (XRD) technique and fractographic analysis. From the results it was found that high welding speed (1400 mm/min) decreased the joint strength. The M23C6 and Ni3Ti carbides were formed in a discrete chain and in a globular form along the grain boundaries of the weld region which increased the strength of the grain boundaries. Fractographic evaluations of the tested specimens for welding speed (1000 and 1200) mm/min showed deep and wide dimples indicating ductile failures.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 30; 115-126
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Heat Input on the Mechanical and Metallurgical Characteristics of TIG Welded Incoloy 800HT Joints
Autorzy:
Arun Kumar, S.
Sathiya, P.
Powiązania:
https://bibliotekanauki.pl/articles/356231.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
incoloy 800 HT
corrosion
aging
sensitization
heat input
Opis:
This study focuses on the effect of heat input on the quality characteristics of tungsten inert arc gas welded incoloy 800HT joints using inconel-82 filler wire. Butt welding was done on specimens with four different heat inputs by varying the process parameters like welding current and speed. The result indicated that higher heat input levels has led to the formation of coarser grain structure, reduced mechanical properties and sensitization issues on the weldments. The formation of titanium nitrides provided resistance to fracture and increased the tensile strength of the joints at high temperatures. Further aging was done on the welded sample at a temperature of 750°C for 500 hours and the metallographic result showed formation of carbides along the grain boundaries in a chain of discrete and globular form which increased the hardness of the material. The formation of spinel NiCr2 O4 provided oxidation resistance to the material during elevated temperature service.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1673-1679
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Study on Ballistic Behaviour of MWCNT / Graphene Reinforced AL6061 Surface Composites Fabricated Via Friction Stir Processing
Autorzy:
Magarajan, U.
Suresh Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/27324483.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ballistic behaviour
friction stir processing
graphene
Multi Walled Carbon Nano Tubes
depth of penetration
Opis:
In this work, a comparative study on the ballistic behaviour of friction stir processed AL6061 targets had been made. Base Metal AL6061 (BM) plates with 25 mm thickness were friction stir processed by adding Multi Walled Carbon Nano Tubes (MWCNT) and Graphene (G), producing AL6061-MWCNT and AL6061-G surface composites. Optical microscopy and microhardness test on BM, AL6061-MWCNT and AL6061-G samples were performed as per the standard procedure. It was noticed that uniform dispersion of ceramic particles and refined grains were obtained for the friction stir processed surface composites. From the microhardness test, it was perceived that friction stir processing had induced strengthening of surface composites, hence increasing the microhardness of AL6061-MWCNT and AL6061-G by ~60.3% and ~73.6% respectively. Also, ballistic experiments were conducted at 680±10 m/s by impacting Ø7.62×51 mm projectiles. AL6063 backing plates were placed to compare the ballistic behaviours AL6061-MWCNT and AL6061-G targets by depth of penetration. It was noted that the depth of penetration of AL6061-MWCNT and AL6061-G targets were 37.81% and 65.84% lesser than the BM target. Further, from the results of Post ballistic microscopy it was observed that the microstructure near and away from the penetration channel edge looks unchanged in BM target. However, the AL6061-MWCNT and AL6061-G targets showed considerable change in their morphology, by forming Adiabatic Shear Bands.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 541--550
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on hybrid modified pathfinder algorithm for optimal reactive power dispatch
Autorzy:
Suresh, V.
Senthil Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/2086822.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optimal reactive power dispatch
ORPD
real-power losses
pathfinder algorithm
PFA
modified pathfinder algorithm
mPFA
hybrid pathfinder algorithm
HPFA
optymalna dyspozycja mocy biernej
strata mocy rzeczywistej
algorytm wyszukiwania najkrótszej drogi
algorytm wyszukiwania najkrótszej drogi zmodyfikowany
algorytm wyszukiwania najkrótszej drogi hybrydowy
Opis:
Hybridization of meta-heuristic algorithms plays a major role in the optimization problem. In this paper, a new hybrid meta-heuristic algorithm called hybrid pathfinder algorithm (HPFA) is proposed to solve the optimal reactive power dispatch (ORPD) problem. The superiority of the Differential Evolution (DE) algorithm is the fast convergence speed, a mutation operator in the DE algorithm incorporates into the pathfinder algorithm (PFA). The main objective of this research is to minimize the real power losses and subject to equality and inequality constraints. The HPFA is used to find optimal control variables such as generator voltage magnitude, transformer tap settings and capacitor banks. The proposed HPFA is implemented through several simulation cases on the IEEE 118-bus system and IEEE 300-bus power system. Results show the superiority of the proposed algorithm with good quality of optimal solutions over existing optimization techniques, and hence confirm its potential to solve the ORPD problem.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 4; e137733, 1--8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflection and transmission of plane waves between two different fluid saturated porous half spaces
Autorzy:
Kumar, R.
Miglani, A.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/202265.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porous
amplitude ratios
reflection
transmission
longitudinal waves
Opis:
The present study is concerned with the reflection and transmission of plane waves between two different fluid saturated porous half spaces when longitudinal and transversal waves impinge obliquely at the interface. Amplitude ratios of various reflected and transmitted waves are obtained .The variations of amplitude ratios with angle of incidence are depicted graphically. A particular case of reflection at the free surface in fluid saturated porous half spaces has been deduced and discussed. A special case of interest has also been deduced from the present investigation.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 2; 227-234
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy based trust management system for cloud environment
Autorzy:
Kumar, S.
Mittal, S.
Singh, M.
Powiązania:
https://bibliotekanauki.pl/articles/102848.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
cloud computing
trust model
fuzzy logic
cloud analyst
Opis:
Cloud computing is a business model with high degree of flexibility, scalability in providing infrastructure, platform and software as a service over the internet. Cloud promises for easiness and reduced expense to service providers and consumers. However, a lack of trust between these two stakeholders has hindered the universal accep¬tance of cloud for outsourced services. In this paper, a fuzzy based trust management system is proposed to facilitate cloud consumers in identifying trustworthy providers. The performance of the proposed system is validated through a simulation using CloudAnalyst and Simulink.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 30; 32-37
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geopolymerisation of Mechanically Activated Lignite and Brown Coal Fly Ash
Autorzy:
Mucsi, G.
Molnár, Z.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/1375557.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Wk
Opis:
Geopolymers have been synthesized from mechanically activated lignite and brown coal fly ash. Mechanical activation of fly ash has been carried out using laboratory ball mill. To determine the structural changes in both, the fly ash and the resulted geopolymer, Fourier transform infrared spectroscopy measurements were performed. Isothermal conduction calorimetry method was applied to study the geopolymerisation reactions in mechanically non-activated (raw) and activated fly ash samples. The isothermal conduction calorimetry results showed similar peak intensity for mechanically activated (5-30 min) fly ash samples. However, the intensity of peak for 120 min milled brown coal fly ash was the highest. The compressive strength of the specimen was found to be dependent on the grinding residence time as well as composition/type of fly ash.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 994-998
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Scheme for Template Security at Feature Fusion Level in Multimodal Biometric System
Autorzy:
Selwal, A.
Gupta, S. K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/102518.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
feature template
biometric data
feature vectors
multimodal biometrics
fuzzy sets
database
feature fusion
Opis:
Biometrics is the science of human recognition by means of their biological, chemical or behavioural traits. These systems are used in many real life applications simply from biometric based attendance system to providing security at a very sophisticated level. A biometric system deals with raw data captured using a sensor and feature template extracted from raw image. One of the challenges being faced by designers of these systems is to secure template data extracted from the biometric modalities of the user and protect the raw images. In order to minimize spoof attacks on biometric systems by unauthorised users one of the solutions is to use multi-biometric systems. Multi-modal biometric system works by using fusion technique to merge feature templates generated from different modalities of the human. In this work, a novel scheme is proposed to secure template during feature fusion level. The scheme is based on union operation of fuzzy relations of templates of modalities during fusion process of multimodal biometric systems. This approach serves dual purpose of feature fusion as well as transformation of templates into a single secured non invertible template. The proposed technique is irreversible, diverse and experimentally tested on a bimodal biometric system comprising of fingerprint and hand geometry. The given scheme results into significant improvement in the performance of the system with lower equal error rate and improvement in genuine acceptance rate.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 31; 23-30
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable gravity effects on thermal instability of nanofluid in anisotropic porous medium
Autorzy:
Chand, R.
Rana, G. C.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/265426.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
porowatość
liczba Rayleigha
zmienna grawitacja
nanofluid
anisotropic porous medium
Rayleigh number
variable gravity
Opis:
In this paper, we study the effects of variable gravity on thermal instability in a horizontal layer of a nanofluid in an anisotropic porous medium. Darcy model been used for the porous medium. Also, it incorporates the effect of Brownian motion along with thermophoresis. The normal mode technique is used to find the confinement between two free boundaries. The expression of the Rayleigh number has been derived, and the effects of variable gravity and anisotropic parameters on the Rayleigh number have been presented graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 3; 631-642
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study of GA & DE algorithm for the economic operation of a power system using FACTS devices
Autorzy:
Bhattacharyya, B.
Gupta, V. K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/141459.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FACTS devices
line power flow
FACTS devices & its optimal locations
genetic algorithm
differential evolution technique
Opis:
The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented.
Źródło:
Archives of Electrical Engineering; 2013, 62, 4; 541-552
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test Methods and Instrumentation for Assessing Reaction to Fire Properties of Railway Rolling Stock
Metody badań i aparatura stosowana do oceny właściwości reakcji taboru kolejowego na ogień
Autorzy:
Gregory, S.
Grayson, S. J.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/215416.pdf
Data publikacji:
2013
Wydawca:
Instytut Kolejnictwa
Tematy:
railway
EN 45545-2
fire
linings
flooring
cables
seats
właściwości palno-dymowe materiałów
badania
aparatura badawcza
jednolite procedury badawcze
Opis:
This paper briefly reviews the current instruments used in assessing the fire performance of railway rolling stock and those to be used in new European regulatory tests. The latter are a result of major developments towards harmonizing Railway Vehicle fire performance testing and classifications, initially developed under European Public Procurement directives and latterly via the Technical Specification for Interoperability (TSI). In many senses the interoperability of railway vehicles between different EU countries makes harmonization a very desirable requirement. The test specifications to be utilized for this process are described in EN 45545. The formation of the European Union and the subsequent agreements that several products should be tested using harmonized testing methods throughout the EU make the EU market the developed world's biggest market for most constructed products. Each member state is currently able to continue to classify the products using the traditional (often national) methods alongside the new methods during a transition period.
Autor przekrojowo omawia rozwój metod badawczych przeznaczonych do badań właściwości palno-dymowych materiałów. Przedstawia przede wszystkim badania i aparaturę stosowaną w Wielkiej Brytanii, a także metody rozwinięte w projektach europejskich oraz testy uwzględnione w nowej normie europejskiej EN 45545:2013. Podkreśla korzystny wpływ ujednolicenia procedur badawczych i wymagań na rozwój europejskiego rynku kolejowego.
Źródło:
Problemy Kolejnictwa; 2013, 160; 35-50
0552-2145
2544-9451
Pojawia się w:
Problemy Kolejnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative potential of different botanicals and synthetic insecticides and their economics against Leucinodes orbonalis in eggplant
Autorzy:
Kumar, S.D.
Masarrat, H.
Muntaha, Q.
Powiązania:
https://bibliotekanauki.pl/articles/66686.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The field experiment was conducted to evaluate the potential of two botanicals viz; ozoneem and neem seed kernel extract (NSKE) and three chemical insecticides viz; imidacloprid, alphamathrin, chlorpyriphos 50% EC + cypermethrin 5% EC against Leucinodes orbonalis, during the years from 2008 to 2009. Botanicals were tested alone and in combination with cultural practices. On the basis of the pooled means, the results revealed that three sprays of chlorpyriphos + cypermethrin @ 0.01% active substance (a.s.) in 15 days intervals was found to be the most economical, resulting in minimum shoot (2.15%) and fruit (12.95%) infestation respectively, followed by alphamathrin @ 0.01% a.s. with a highest marketable yield of 87.77 q/ha. Maximum marketable yield was received from the treatment with alphamathrin, but due to high costs involved in the use of this chemical, it took second place. Three sprays of NSKE @ 5 ml/lt. recorded a maximum of shoot (3.91%) and fruit (24.49%) infestation, respectively. However, shoot and fruit infestation was brought down and marketable yield increased to some extent, when these treatments were combined with cultural methods. It is therefore, suggested that the combination of chlorpyriphos 50% EC + cypermethrin 5% EC, being the most effective and economically viable insecticide, can be utilized as a valuable chemical component in Integrated Pest Management to manage the L. orbonalis in eggplant crop.
Źródło:
Journal of Plant Protection Research; 2012, 52, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal convection of magneto compressible couple-stress fluid saturated in a porous medium with Hall current
Autorzy:
Mehta, C. B.
Singh, M.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/265186.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
pole magnetyczne
ściśliwość
porowatość
prądy Hall'a
couple stress fluids
horizontal magnetic field
compressibility
porous medium
Hall currents
Opis:
An investigation is made on the effect of Hall currents on thermal instability of a compressible couple-stress fluid in the presence of a horizontal magnetic field saturated in a porous medium. The analysis is carried out within the framework of the linear stability theory and normal mode technique. A dispersion relation governing the effects of viscoelasticity, Hall currents, compressibility, magnetic field and porous medium is derived. For the stationary convection a couple-stress fluid behaves like an ordinary Newtonian fluid due to the vanishing of the viscoelastic parameter. Compressibility, the magnetic filed and couple-stress parameter have stabilizing effects on the system whereas Hall currents and medium permeability have a destabilizing effect on the system, but in the absence of Hall current couple-stress has a destabilizing effect on the system. It has been observed that oscillatory modes are introduced due to the presence of viscoelasticity, magnetic field porous medium and Hall currents which were non-existent in their absence.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 1; 83-93
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
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:
Evidence of amorphous Ca-phosphate precipitate caused by bio mineralisation in 4-5th CE lime plasters of the previously submerged east coastal monument of Salvankuppam
Autorzy:
Singh, Manager R.
Kumar, S. Vinodh
Ganaraj, Kuntikana
Powiązania:
https://bibliotekanauki.pl/articles/2086560.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
Amorphous Ca-phosphate
16S rRNA
Bio-mineralization
calcite
lime plasters
Opis:
The lime plasters of the excavated monument of Salvankuppam, previously submerged and exposed by the Tsunami occurred in the Indian Ocean on 26th December 2004 was studied with different analytical techniques. The temple is dated 4-5th century CE. The XRF, XRD, FTIR, NMR, SEM-EDX analysis of the lime plasters evidenced particular occurrence of phosphatised bacterial remains in saline conditions. The formation of amorphous Ca-phosphate by bio mineralization was identified in the plasters by the analyses. The plasters are made of air-lime with coarse aggregates and seashells inclusion as confirmed by the thermal and chemical analysis. The microstructure and morphological investigations of mineralized microbial structures by SEM-EDX indicated the formation of amorphous Ca-phosphate. The unordered and fibrous spherulites have hardened and reduced porosity of the plaster by bio mineralization as observed through MIP analysis. The 16S rRNA sequencing has identified the Pseudomonas strains mainly responsible for the clustering of amorphous Ca-phosphate particles around the bacterial colony.
Źródło:
Mineralogia; 2021, 52, 1; 19--30
1899-8291
1899-8526
Pojawia się w:
Mineralogia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of acoustically induced refractive index perturbation in silicon and germanium slab for optical applications
Autorzy:
Sharma, G.
Kumar, S.
Kumar, D.
Singh, V.
Powiązania:
https://bibliotekanauki.pl/articles/173371.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dispersion relation
Lamb wave mode in silicon and germanium
displacement field
refractive index modulation
Opis:
In-plane displacement field and refractive index variation for silicon and germanium in the presence of Lamb wave is estimated for optical applications. The required dispersion equation in a thin silicon and germanium plates is obtained using the method of potentials with boundary conditions involving the bulk and surface stress of the materials considered. The eigen-values thus obtained are used to compute the Lamb wave modes for the slab of silicon and germanium at same thickness. The fundamental anti-symmetric and symmetric plate modes and their overtones are observed due to confinement of acoustic energy within the slab thickness. In addition, the excited symmetric modes in silicon have longer wavelengths than those of germanium at a fixed frequency. Therefore, the refractive index modulation through the Lamb wave in silicon is always larger as compared to that of germanium. This refractive index modulation can be treated as periodic sinusoidal refractive index variation and may be considered as a tunable one-dimensional photonics crystal.
Źródło:
Optica Applicata; 2015, 45, 4; 491-500
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on fungi inhabiting indoor woods and their eco-friendly management
Autorzy:
Tapwal, A.
Kalyan, P.
Kumar, S.
Chandra, S.
Powiązania:
https://bibliotekanauki.pl/articles/11389.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Źródło:
International Letters of Natural Sciences; 2016, 59
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of Solubility and Mass Transfer Coefficient of Benzoic Acid Through Hydrotropy
Autorzy:
Prakash, G.D.
Kumar, S.T.
Gandhi, N.N.
Powiązania:
https://bibliotekanauki.pl/articles/779266.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
hydrotropy
solubilization
mass-transfer coefficient
benzoic acid
Opis:
The effect of hydrotropes such as sodium salicylate, sodium benzoate, and nicotinamide on the solubility and mass transfer coefficient of benzoic acid has been investigated. The solubility studies were carried out under a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303K to 333K). It has been observed that the solubility and mass transfer coefficient of benzoic acid increases with an increase in hydrotrope concentration and also with system temperature. A Minimum Hydrotrope Concentration (MHC) was found essential to initiate a significant increase in the solubility and the mass transfer coefficient. The maximum enhancement factor (?s), which is the ratio of the solubility value in the presence and absence of a hydrotrope, has been determined for all sets of experimentations. The solubility of benzoic acid has been enhanced to 19.98 times in the presence of 2.5 mol/L concentration of sodium salicylate hydrotrope at 333K.The effectiveness of hydrotropes was measured in terms of Setschenow constant Ks and the highest value has been observed as 0.502 for sodium salicylate.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 1; 46-50
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of hydrotropes on the solubility and mass transfer coefficient of 2-nitrobenzoic acid
Autorzy:
Thenesh-Kumar, S.
Gnana-Prakash, D.
Nagendra-Gandhi, N.
Powiązania:
https://bibliotekanauki.pl/articles/779314.pdf
Data publikacji:
2009
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
hydrotrop
solubilizacja
współczynnik wymiany masy
separacja
hydrotropy
solubilization
mass transfer coefficient
separation
Opis:
A comprehensive investigation on the solubility and mass transfer coefficient enhancement of 2-nitrobenzoic acid through hydrotropy, has been undertaken. The solubility and mass transfer coefficient studies were carried out using hydrotropes such as sodium acetate, citric acid and nicotinamide under a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303 to 333 K). It was found that the solubility and mass transfer coefficient of 2-nitrobenzoic acid increases with an increase in hydrotrope concentration and also with system temperature. All hydrotropes used in this work showed an enhancement in the solubility and mass transfer coefficient to different degrees. The maximum enhancement factor value has been determined for both the solubility and mass transfer coefficient. The effectiveness of hydrotropes was measured in terms of Setschnew constant Ks and reported for all the hydrotropes used in this study.
Źródło:
Polish Journal of Chemical Technology; 2009, 11, 2; 55-59
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion Inhibition of Mild Steel in Nitric Acid Media by some Schiff Bases Derived from Anisalidine
Autorzy:
Saxena, N.
Kumar, S.
Sharma, M. K.
Mathur, S. P.
Powiązania:
https://bibliotekanauki.pl/articles/779278.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Schiff base
degradation
inhibitor and mild steel
Opis:
Corrosion inhibition performance of mild steel in nitric acid solution containing different concentration of anisalidine derivative Schiff bases viz. N- (4-nitro phenyl) p-anisalidine (SB1), N- (4-chloro phenyl) p-anisalidine (SB2), N- (4-phenyl) p-anisalidine (SB3), N- (4-methoxy phenyl) p-anisalidine (SB4), N- (4-hydroxy phenyl) p-anisalidine (SB5) has been investigated using mass loss, thermometric and potentiostate polarization technique. Inhibition efficiencies of Schiff bases have been evaluated at different acid strength. The inhibition efficiency was found larger than their parent amines. Inhibition efficiencies of synthesized Schiff bases increase with inhibitor concentration. Inhibition efficiency increases up to 98.32% with ansalidine derivative Schiff base.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 1; 61-67
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytochemical and pharmacological aspects of Nothapodytes nimmoniana. An overview
Profil fitochemiczny i farmakologiczny Nothapodytes nimmoniana. Przegląd
Autorzy:
Khan, N.
Tamboli, E.T.
Sharma, V.K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/72676.pdf
Data publikacji:
2013
Wydawca:
Instytut Włókien Naturalnych i Roślin Zielarskich
Tematy:
phytochemistry
pharmacology
Nothapodytes nimmoniana
Icacinaceae
camptothecin
medicinal property
human disease
treatment
Opis:
Nothapodytes nimmoniana (J. Graham) (Icacinaceae), commonly known as Amruta is found in India particularly in Maharashtra, Goa, Kerala, Assam, Jammu and Kashmir as well as Tamilnadu areas. It is an important medicinal plant, the major source of a potent alkaloid, namely camptothecin, of a wide spectrum of pharmacological activities like anti-cancer, anti-HIV, antimalarial, antibacterial, anti-oxidant, anti-inflammatory, anti-fungal and also applied in the treatment of anaemia. Camptothecin is still not synthesized, therefore, its production entirely depends on natural sources. N. nimmoniana is one such plant which yields contain camptothecin in significantly high amount. The plant is gaining international recognition due to its diversified medicinal uses. It is subjected to excessive harvest. It has been categorized as a vulnerable and endangered plant. The present review encompasses the phytochemical, analytical, pharmacological, biotechnological, and other specific aspects of N. nimmoniana.
Nothapodytes nimmoniana (J. Graham) (Icacinaceae), powszechnie znana jako Amruta, rośnie w Indiach, szczególnie w prowincjach Maharashtra, Goa, Kerala, Assam, Dżammu i Kaszmir, a także na niektórych obszarach Tamilnadu. Jest jedną z ważnych roślin leczniczych, głównym źródłem silnego alkaloidu, kamptotecyny, mającej szerokie spektrum działania: przeciwnowotworowe, anty-HIV, antymalaryczne, antybakteryjne, przeciwutleniające, przeciwzapalne, przeciwgrzybicze. Znajduje również zastosowanie w leczeniu anemii. Jak dotąd kamptotecyna nie została zsyntetyzowana, dlatego jej produkcja całkowicie zależy od źródeł naturalnych. N. nimmoniana jest jedną z roślin zawierających duże ilości kamptotecyny. Zyskała ona międzynarodowe uznanie dzięki szerokiemu spektrum zastosowań, co powoduje zwiększenie jej eksploatacji. Z tego powodu została uznana za gatunek zagrożony. Poniższy przegląd obejmuje badania fitochemiczne, analityczne, farmakologiczne, biotechnologiczne i inne prowadzone nad gatunkiem N. nimmoniana.
Źródło:
Herba Polonica; 2013, 59, 1
0018-0599
Pojawia się w:
Herba Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameter Characterization in Processing of Silver - Aluminum Based Electrical Contact Materials
Autorzy:
Praveen Kumar, S.
Parameshwaran, R.
Ananthi, A.
Jenil Jaba Sam, J.
Powiązania:
https://bibliotekanauki.pl/articles/352711.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical contactor
silver
aluminum
tin oxide
conduction
Opis:
An electrical contractor is one which plays significant role in day todays life in industries as well as in home appliances. In current scenario the materials for conducting purpose has an overwhelming research capability. Now a day the silver based electrical contact composite material have provided the potential applications in aerospace and automobile industries. Among silver based contact material the silver cadmium oxide and silver tin oxide plays a vital role in fabrication of electrical contactors. In this research an attempt has been made to study the influence of adding Aluminum with silver based electrical contact composite materials by two different processing routes namely stir-casting and powder metallurgy. Silver and aluminum matrix plays a virtual role in composite world owing to their highest conductivity. Optimum parameters were identified for attaining the maximum properties such as conductivity, hardness, density, and porosity of composition. By this better conducting property and mechanical property of the electrical contact can be improved by this system. Thus a screening test has be conducted with addition of Al with silver tin oxide compositions hence this paper aims to process the aluminum – silver based electrical contact materials by stir casting processing and powder metallurgy route and compare the results obtained.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1895-1901
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Stannous-Cerium Oxide Nanocomposites as Nanofilm, Nanodot and Nanorod
Autorzy:
Budhiraja, N
Sharma, A.
Kumar, S.
Kaur, A.
Unikrishnan, N. V.
Powiązania:
https://bibliotekanauki.pl/articles/411664.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
nanofilms
Nanowires
nanoparticles
Crystallography
Topography
Opis:
In the present paper, main emphasis is given to synthesize the Stannous-Cerium oxide nanocomposites in nanofilms, nanodots and nanorods by Chemical bath method, Chemical drop method and Chemical rolling Method. These nanocomposite materials are synthesized on a glass substrate at 100 °C temperature. Crystallography investigation of these materials is done by X-ray diffraction (XRD) which reveals that average grain size is 58.9 nm and 62.3 nm for nanofilms and nanodots on glass substrate respectively whereas XRD diffraction for nanorod on glass substrate reveals that material is amorphous in nature.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 14; 69-79
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient finite element simulation and microstructure evolution of AA2219 weld joint using gas tungsten arc welding process
Autorzy:
Arunkumar, S.
Shrikrishna, A. K.
Paulraj, S.
Devakumaran, K.
Kumar, S. R.
Powiązania:
https://bibliotekanauki.pl/articles/101882.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
AA2219 aluminium alloy
gas tungsten arc welding
finite element simulation
metallurgical characterization
Opis:
In this study we focus on finite element simulation of gas tungsten arc welding (GTAW) of AA2219 aluminum alloy and the behavioral of the microstructure before and after weld. The simulations were performed using commercial COMSOL Multiphysics software. The thermal history of the weld region was studied by initially developed mathematical model. A sweep type meshing was used and transient analysis was performed for one welding cycle. The highest temperature noted was 3568 °C during welding. The welding operation was performed on 200×100×25 mm plates. Through metallurgical characterization, it was observed that a fair copper rich cellular (CRC) network existed in the weld region. A small amount of intermetallic compounds like Al2Cu is observed through the XRD pattern.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 31; 64-73
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Meiotic studies in some members of Caryophyllaceae Juss. from the Western Himalayas
Autorzy:
Jeelani, S.M.
Rani, S.
Kumar, S.
Kumari, S.
Gupta, R.C.
Powiązania:
https://bibliotekanauki.pl/articles/19318.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Caryophyllaceae
Himalayas
meiotic process
chromosome number
meiosis
Western Himalayas
pollen grain size
Arenaria kashmirica
Silene conoidea
Silene edgeworthii
Silene moorcroftiana
Silene nepalensis
Stellaria media
Stellaria monosperma
Stellaria semivestita
Lychnis coronaria
Silene vulgaris
India
Gypsophilla ceratioides
Opis:
The paper reports meiotic studies on 50 populations comprising 12 species belonging to 5 genera of Caryophyllaceae from the Western Himalayas. The chromosome numbers in Arenaria kashmirica (n=20), Silene conoidea (n=20), S. edgeworthii (n=12 and n=24), S. moorcroftiana (n=24), S. nepalensis (n=12), Stellaria media (n=13), S. monosperma (n=13) and S. semivestita (n=13) are reported for the first time. The chromosome numbers in Lychnis coronaria (n=12) and Silene vulgaris (n=24) are given for the first time from India, along with Gypsophilla ceratioides (n=15) from the Western Himalayas. The course of meiosis varies from normal to abnormal in different populations of Silene conoidea, S. edgeworthii, S. vulgaris, Stellaria media, S. monosperma and S. semivestita. The course of meiosis was abnormal in all studied populations of Lychnis coronaria. Abnormal microsporogenesis (cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges) led to reduced pollen fertility and differences in pollen grain size.
Źródło:
Acta Biologica Cracoviensia. Series Botanica; 2011, 53, 1
0001-5296
Pojawia się w:
Acta Biologica Cracoviensia. Series Botanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of $Fe_4[Fe(CN)_6]_3$·$14H_2O$ Nanopowder by Co-Precipitation Technique and Effect of Heat Treatment
Autorzy:
Rohilla, S.
Lal, B.
Sunder, S.
Aghamkar, P.
Kumar, S.
Aggarwal, A.
Powiązania:
https://bibliotekanauki.pl/articles/1535871.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
64.70.Nd
61.82.Rx
Opis:
Nanopowder of iron cyanide hydrate (member of Prussian blue family) was obtained using ferric chloride and potassium cyanide in their dilute solution through co-precipitation method. The effect of thermal annealing on iron cyanide hydrate nanocrystallites have been studied in detail. The formation of $Fe_4[Fe(CN)_6]_3$·$14H_2O$ and iron oxides was revealed by the Fourier transform infrared spectroscopy. The crystal structure, morphology and size of nanocrystallites were investigated by X-ray diffraction and transmission electron microscope. Results suggest that using co-precipitation technique, nanopowder of iron cyanide hydrate, in typically spherical shape, can be obtained and their thermal treatment also yield iron oxide nanocrystallites of spherical with good homogeneity. The size of the prepared nanocrystallites was found in the range 20-36 nm. It was observed that thermal treatment, typically at 800°C (4 h), iron cyanide hydrate ($Fe_4[Fe(CN)_6]_3$·$14H_2O$) nanocrystallites transformed into iron oxide ($α-Fe_2O_{3,}$ hematite) nanocrystallites.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 696-700
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Cutting Forces and Chip Microstructure in High Speed Machining of Carbon Fiber - Epoxy Composite Tube
Autorzy:
Allwin Roy, Y.
Gobivel, K.
Vijay Sekar, K. S.
Suresh Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/352953.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
composite materials
orthogonal machining
cutting forces
chip microstructure
Opis:
Carbon fiber reinforced polymeric (CFRP) composite materials are widely used in aerospace, automobile and biomedical industries due to their high strength to weight ratio, corrosion resistance and durability. High speed machining (HSM) of CFRP material is needed to study the impact of cutting parameters on cutting forces and chip microstructure which offer vital inputs to the machinability and deformation characteristics of the material. In this work, the orthogonal machining of CFRP was conducted by varying the cutting parameters such as cutting speed and feed rate at high cutting speed/feed rate ranges up to 346 m/min/ 0.446 mm/rev. The impact of the cutting parameters on cutting forces (principal cutting, feed and thrust forces) and chip microstructure were analyzed. A significant impact on thrust forces and chip segmentation pattern was seen at higher feed rates and low cutting speeds.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1771-1777
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transformational green sustainable concepts in the field of infrastructure
Implementacja zielonych zrównoważonych rozwiązań w infrastrukturze
Autorzy:
Devarajan, P.
Kozarzewska, A.
Vijayan, D.S.
Kumar, S.
Sivasuriyan, A.
Sitek, W.
Powiązania:
https://bibliotekanauki.pl/articles/28765637.pdf
Data publikacji:
2024
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Źródło:
Acta Scientiarum Polonorum. Architectura; 2024, 23; 56-78
1644-0633
Pojawia się w:
Acta Scientiarum Polonorum. Architectura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ballistic studies of lightweight materials - a review
Autorzy:
Balaji, S.
Kumar, S. Dharani
Moorthy, K. Chandra
Javeed, M. Mohamed
Dharanidharan, D.
Powiązania:
https://bibliotekanauki.pl/articles/95205.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
lightweight materials
ballistics
heat treatment
numerical studies
materiały lekkie
balistyka
obróbka cieplna
badania modelowe
Opis:
A recent development in the material studies provides beneficial application of lightweight alloys such as aluminium, magnesium as well as composites and metal matrices. The alloys are experimentally improved by increasing hardness in the ballistics testing using projectiles,makes them viable for the areas such as aerospace, military, defence, automobiles and so on. So the study is made on different approaches. First, by comparing different types of non-ferrous alloys and projectiles regarding sizes, structures. Second, the materials with heat treatment are also studied for investigating the hardness property by overcoming successful penetration on non-ferrous alloys. Third, material to be improvised by use of numerical studies such as 3D models, empirical models and software such as ANSYS, ABAQUS and AUTODYN, etc. Finally, the aim of this paper is to review the recent progress ballistic studies of lightweight materials and to provide a best choice of material for further on-going research.
Źródło:
Journal of Mechanical and Energy Engineering; 2020, 4, 1; 7-14
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Xorshift random number generators from primitive polynomials
Autorzy:
Kumar Bishoi, S.
Narayan Maharana, S.
Powiązania:
https://bibliotekanauki.pl/articles/375858.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
random number generators
Xorshift generator
primitive polynomials
linear feed-back shift registers
multiple-recursive matrix method
generatory liczb losowych
generator Xorshift
Opis:
A class of Xorshift Random Number Generators (RNGs) are introduced by Marsaglia. We have proposed an algorithm which constructs a primitive Xorshift RNG from a given prim- itive polynomial. We also have shown a weakness present in those RNGs and suggested its solution. A separate algorithm also proposed which returns a full periodic Xorshift generator with desired number of Xorshift operations.
Źródło:
Theoretical and Applied Informatics; 2017, 29, 1-2; 1-13
1896-5334
Pojawia się w:
Theoretical and Applied Informatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Evaluation of the Thermal Properties of Di-, Tri- and Tetra-Azido-Esters
Autorzy:
Kumar, S.
Kumar, A.
Yamajala, K. D. B.
Gaur, P.
Kumar, D.
Banerjee, S.
Powiązania:
https://bibliotekanauki.pl/articles/358266.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
azido-esters
energetic plasticizers
DFT
contact angle
Opis:
A group of polycyclic and aliphatic azido-esters (as energetic plasticizers) have been synthesized by simple synthetic routes and their molecular structures were confirmed by spectroscopic techniques. In addition, their thermal and rheological properties have been determined utilizing DSC, TGA, viscosity, and contact angle. Computational studies of these plasticizers have been performed by means of DFT (B3LYP/6-31G*) to estimate possible stable structures, energies, heat of formation, bond dissociation energies, IR and NMR spectra etc. Their compatibility with glycidyl azide polymer (GAP) binder was studied to explore their applicability in propellants. All of these molecules are novel and have been synthesized with the possibility of scale up.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 844-860
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatio-temporal variations in sulfur-oxidizing and sulfate-reducing bacterial activities during upwelling, off South-West coast of India
Autorzy:
Kamaleson, A.S.
Gonsalves, M.-J.
Kumar, S.
Jineesh, V.K.
LokaBharathi, P.A.
Powiązania:
https://bibliotekanauki.pl/articles/47551.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
spatio-temporal variability
sulphate reduction
sulphur oxidation
bacterial activity
microbial degradation
environment parameter
upwelling
Arabian Sea
India
coastal water
Źródło:
Oceanologia; 2019, 61, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particle-inflow-gun-mediated genetic transformation of buffel grass [Cenchrus ciliaris L.]: optimizing biological and physical parameters
Autorzy:
Bhat, V
Dalton, S.J.
Kumar, S.
Bhat, B.V.
Gupta, M.G.
Morris, P.
Powiązania:
https://bibliotekanauki.pl/articles/2048302.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
buffel grass
promoter
genetic transformation
physical parameter
Cenchrus ciliaris
biological parameter
grass
biotechnology
Źródło:
Journal of Applied Genetics; 2001, 42, 4; 405-412
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of advanced solar panel technologies in buildings – A review
Rozwój zaawansowanych technologii paneli fotowoltaicznych w budynkach – przegląd
Autorzy:
Kumar, S.
Vijayan, D.S.
Devarajan, P.
Sivasuriyan, A.
Koda, E.
Sitek, W.
Wodzyński, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/28765640.pdf
Data publikacji:
2024
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Źródło:
Acta Scientiarum Polonorum. Architectura; 2024, 23; 79-93
1644-0633
Pojawia się w:
Acta Scientiarum Polonorum. Architectura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photocatalytic degradation of ampicillin using silver nanoparticles biosynthesised by Pleurotus ostreatus
Autorzy:
Jassal, P.S.
Khajuria, R.
Sharma, R.
Debnath, P.
Verma, S.
Johnson, A.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/2096973.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ampicillin
FTIR
photocatalysis
silver nanoparticles (Ag-NPs)
TEM
Opis:
The past few decades have witnessed a tremendous increase in the consumption of antibiotics worldwide. This rampant and unregulated use of antibiotics and their improper disposal has led to the accumulation of these drugs in the environment. This in turn has led to the emergence of antibiotic resistance in microbes and has become one of the most pressing global concerns in medicine, with highly resistant pathogens of many species proving difficult to treat. The aim of the study was to synthesise silver nanoparticles (Ag-NPs) using white rot fungus, Pleurotus ostreatus and assess its potential to carry out photocatalytic degradation of ampicillin. UV–Vis spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscope have been used to characterize biosynthesized Ag-NPs. The photocatalytic degradation of ampicillin in aqueous solution by Ag-NPs was evaluated under natural sunlight. The effect of the operating conditions (contact time, Ag-NP concentration and initial ampicillin concentration) on the photocatalytic degradation was also investigated. The highest ampicillin degradation of 96.5% was observed after exposure of the solution (antibiotic + nanoparticles) for 4 h in sunlight. The maximum degradation was observed at an Ag-NP concentration of 5 ppm at pH 6. To the best of our knowledge, photocatalytic degradation of ampicillin using Ag-NPs synthesised by P. ostreatus has not been reported earlier.
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2020, 101, 1; 5-14
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In vitro micropropagation of Acacia auriculiformis from selected juvenile sources
Autorzy:
Ismail, H.
Kumar, S.M.
Aziah, M.Y.
Hasnida, N.H.
Nor Aini, A.S.
Powiązania:
https://bibliotekanauki.pl/articles/41196.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
in vitro
micropropagation
Acacia auriculiformis
juvenile source
Opis:
The effects of 6- Benzylaminopurine (BA), different basal medium, sucrose concentration and gelling agent were investigated for shoot induction and multiplication of Acacia auriculiformis. Nodal explants derived from 5-month-old seedlings yielded the highest shoot multiplication rate in Murashige and Skoog medium (MS) with 0.44 μM BA, 30 g/L sucrose and 2 g/L Gelrite. The highest mean number of shoots (10) and mean length of shoots (5.07mm) were also obtained in this medium. Qualitative observation of the shoots cultured in 0.44 μM BA were greener and vigorous in growth as compared to shoots cultured on higher concentrations of BA (22.2 μM). MS medium produced a significantly higher number of shoots (18) compared to Woody Plant Medium (WPM) (11) and B5 medium (10). Media solidified with different gelling agents also produced a significantly different number of shoots with 2 g/L Gelrite produced the highest number of shoots (23). The highest percentage of shoots rooted was found in the MS medium without any growth regulators (40.0%) followed by medium supplemented with Indole-3-butyric acid (IBA) at 9.84 μM and the combination of 9.84 μM IBA with 5.37 μM α-naphthalene acetic acid (NAA) (33.3%). MS medium without any plant growth regulators produced the highest mean root length (84.33mm), whereas medium supplemented with 9.84 μM IBA produced the highest mean number of roots per shoot (4.33). Out planting of in vitro rooted shoots in shredded coconut husk as the substrate gave the highest percentage of survival (90%) during acclimatization in the greenhouse.
Źródło:
Dendrobiology; 2016, 75
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Spin-Valve Transistor - a New Magnetoelectronic Device
Autorzy:
Anil Kumar, P. S.
Lodder, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/2011222.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.70.-i
75.70.Pa
Opis:
A spin-valve transistor showing high sensitivity at low fields was developed. A large magnetocurrent, above 500% is realized by a magnetic field change of 2 to 4 Oe at 80 K. Hot electrons are injected into the spin-valve layer through a Si-Pt Schottky diode. These hot electrons, while traversing through the spin-valve, are spin-dependently scattered. Those electrons with right energy and momentum are collected by a collector (an Au-Si Schottky diode) constituting a collector current. The relative orientation of the magnetic layer in the spin-valve is changed by the application of a magnetic field and causes a change in collector current giving a large magnetocurrent.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 111-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chatter detection using principal component analysis in cold rolling mill
Autorzy:
Usmani, N. I.
Kumar, S.
Velisatti, S.
Tiwari, P. K.
Mishra, S. K.
Patnaik, U. S.
Powiązania:
https://bibliotekanauki.pl/articles/329460.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
chatter
principal component analysis
PCA
cold rolling
vibration
drgania samowzbudne
analiza składowych głównych
walcowanie na zimno
drgania
Opis:
Most cold rolling mills are prone to chatter problem. Chatter marks are often observed on the strip surface in cold rolling mill leading to downgrade and rejection of rolled material. Chatter impact product quality as well as productivity of mill. In absence of online chatter detection no corrective action can be taken immediately and whole campaign gets affected. Most conventional approach for online chatter detection is by using vibration measurement of mill stands in time & frequency domain. Present work proposes two approaches to detect chatter in cold rolling mill using a statistical technique called Principal Component Analysis (PCA). In this paper two methods are used for chatter detection. First method applies PCA on Fast Fourier Transform (FFT) to differentiate between chatter and non-chatter condition. Second method applies PCA on statistical parameters calculated from raw vibration data to detect chatter.
Źródło:
Diagnostyka; 2018, 19, 1; 73-81
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies