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1
Content available Slip regime MHD 2-liquid plasma heat transfer flow with hall currents between parallel plates
Linga Raju T., Satish P.
International Journal of Applied Mechanics and Engineering
|
2023
|
Vol. 28, no. 3
65--85
EN
The influence of the slip factor on the MHD 2-liquid heat transfer flow of ionized gases within a channel between two non-conducting plates with Hall currents is investigated theoretically. Slip conditions were used to obtain solutions for the velocity and temperature fields, as well as the heat transfer rates. The flow characteristics of the two liquids are studied for estimates of the leading parameters, for instance the magnetic parameter, Hall and slip factors, viscosity, density, height, electrical conductivity and the thermal conductivity ratios. It was observed that an upsurge in temperature in the two zones is caused by the thermal conductivity proportion. The rate of heat transfer coefficient diminishes up to a certain point, after that it starts to increase as the magnetic and Hall parameters increase.
2
Content available An unsteady electro-magnetohydrodynamic two-liquid plasma flow along a channel of insulating porous plates with Hall currents
Rao V. Gowri Sankara, Raju T. Linga
International Journal of Applied Mechanics and Engineering
|
2023
|
Vol. 28, no. 2
90--112
EN
It is proposed to use the Hall currents to model the transient magneto-hydrodynamic two liquid flows and heat transfer of ionized gases propelled by a common pressure gradient via a horizontal channel consisting of parallel porous plates. For the distributions of velocity and temperature, the principal partial differential equations that explain heat transfer flow under the chosen constraints are resolved. Graphical representations are given for the distributions of velocity, temperature, and heat transfer rates. This research will be carried out using non-conducting porous plate’s channel.
3
Content available remote Hall effect test bench for temperature dependence of carrier concentration
Dyndał Katarzyna, Sobków Zbigniew, Sanetra Jerzy, Marszałek Konstanty W.
Przegląd Elektrotechniczny
|
2022
|
R. 98, nr 9
231--234
EN
This paper presents an integrated bench for Hall effect measurements consisting of a helium cryostat placed between the electromagnet poles with a field of 0.5 T and a control and measurement system, as well as control algorithm for different operating modes. The results of measurements of majority carrier concentration by van der Pauw method in the temperature range 165 K - 300 K for indium tin oxide (ITO).
PL
W artykule przedstawiono zintegrowane stanowisko do pomiaru efektu Hall’a składające się z helowego kriostatu umieszczonego między nabiegunnikami elektromagnesu o polu 0,5 T oraz systemu kontrolno-pomiarowego, a także algorytmu sterowania dla różnych modów pracy. Zaprezentowano wyniki pomiarów koncentracji nośników większościowych metodą van der Pauw’a w zakresie temperatur od 165 K do 300 K dla warstw tlenku indowo-cynowego (ITO).
4
Content available The Hall effect on MHD 2-fluid unsteady heat transfer flow of plasma in a rotating system via a straight channel between conducting plates
Raju T. Linga, Rao B. Venkata
International Journal of Applied Mechanics and Engineering
|
2022
|
Vol. 27, no. 3
137--162
EN
Hall currents are used to investigate MHD unsteady two fluid flows and heat transport of plasma along a straight channel of conducting plates. In the two liquid zones, the velocity and temperature fields for the case of conducting side plates are obtained by solving the governing equations using a two-term series under the specified conditions. The distribution profiles are graphically resolved and examined. The distributions are thought to be dependent on the electron-to-total pressure ratio. The flow and heat transfer factors are also influenced by other parameters such as the Hartmann number, Hall parameter, rotation parameter, thermal conductivity and viscosity ratio.
5
Content available Topologiczna materia kwantowa
Haldane John F. Duncan M., Chankowski Piotr
Postępy Fizyki
|
2021
|
T. 72, z. 1
32--45
PL
[Wykład noblowski wygłoszony 8 grudnia 2016. John F. Duncan M. Haldane, Department of Physics, Princeton University. Opublikowany w jezyku polskim za zgoda Nobel Foundation ©the Nobel Foundation 2016. Przekład dokonany przy wsparciu finansowym Fundacji Pro-Physica]. Omawiam historię i okoliczności trzech wymienionych w tytule przyznania tej Nagrody Nobla odkryć: topologicznego wzoru „TKNN” dotyczącego całkowitego efektu Halla podanego przez Davida Thoulessa i jego współpracowników, izolatora Cherna, czyli anomalnego kwantowego efektu Halla oraz rolę jaką odegrał on w późniejszym odkryciu topologicznych izolatorów niezmienniczych względem operacji odwrócenia czasu i wreszcie nieoczekiwanego odkrycia topologicznego stanu typu cieczy spinowej kwantowego łańcucha antyferromagnetycznego utworzonego ze spinów S = 1, który stanowił pierwszy przykład topologicznej kwantowej materii. Powiem też, jak te pierwsze odkrycia doprowadziły do powstania niezwykle interesującej i obecnie wyjątkowo aktywnie rozwijanej dziedziny, jaką jest fizyka „topologicznej materii”.
EN
I will describe the history and background of three discoveries cited in this Nobel Prize: he “TKNN” topological formula for the integer quantum Hall effect found by David houless and collaborators, the Chern Insulator or quantum anomalous Hall effect, and its role in the later discovery of time-reversal-invariant topological insulators, and the unexpected topological spin-liquid state of the spin S=1 quantum antiferromagnetic chain, which provided an initial example of topological quantum matter. I will summarize how these early beginnings have led to the exciting, and currently extremely active, field of “topological matter.”
6
Content available Heat and mass transfer effect on an infinite vertical plate in the presence of Hall current and thermal radiation with variable temperature
Manjula L., Muthucumaraswamy R.
International Journal of Applied Mechanics and Engineering
|
2021
|
Vol. 26, no. 3
131--140
EN
MHD and radiated heat flow on a rotating system of an electrically conducting fluid in the presence of Hall current under the influence of variable temperature is studied analytically. An exact solution of a non-dimensional form of coupled partial differential equations is obtained by the technique of Laplace transform. The effect of temperature, velocity and concentration is analyzed for various parameters like the Hall parameter [...], thermal radiation [...], rotation parameter [...], Hartmann number [...] and results are discussed in detail with the help of graphs. A mixed analysis of a rotating fluid with Hall current and thermal radiation plays a very essential role in the research area such as plasma physics, MHD generator, fluid drift sensor, cosmological and geophysical level, etc.
7
Content available remote Metodyka określania parametrów elektrycznych warstw GaSb osadzonych na przewodzącym podłożu
Kotowski Mateusz, Czuba Krzysztof, Smoczyński Dariusz, Jasik Agata
Przegląd Elektrotechniczny
|
2019
|
R. 95, nr 9
123--126
PL
W artykule podjęto próbę określenia parametrów warstw epitaksjalnych GaSb o różnej koncentracji atomów berylu osadzonych na przewodzących podłożach GaSb o dziurowym typie przewodnictwa. Wykorzystano do tego zaproponowany w literaturze model wielowarstwowy, który zweryfikowano przez pomiar parametrów elektrycznych warstwy GaSb osadzonej na półizolującym podłożu GaAs. Stwierdzono, że model pozwala poprawnie określać parametry elektryczne warstw wówczas, gdy przewodność całej struktury jest większa niż przewodność podłoża. W przypadku odwrotnym otrzymano zawyżone wartości ruchliwości nośników w temperaturze pokojowej w porównaniu do wartości uzyskanych w temperaturze 77 K dla koncentracji nośników ok. 5 x 1017 cm3.
EN
In the paper, an attempt was made to determine electrical parameters of GaSb:Be layers with various doping concentration grown on conductive p-type substrate. A multi-layer model proposed by Arnaudov et al [10] was used. To verify it, the model was applied to the experimental data obtained for GaSb/GaAs(SI) sample. It was proven that the model correctly calculates electrical parameters, when the conductivity of the entire sample is larger than that of a substrate. In the opposite situation, overestimated values of hole mobility at room temperature were obtained for GaSb layer with p = 5 x 1017 cm3 in comparison with correct values at 77 K.
8
Content available Kondensator wzorcowy 10 nF z dielektrykiem ceramicznym
Koszarny M., Jursza J., Szutkowski J., Jasiński R., Szterk P.
Metrologia i Probiernictwo : biuletyn Głównego Urzędu Miar
|
2018
|
nr 2 (21)
50--52
PL
W ramach prac badawczo-rozwojowych, w Samodzielnym Laboratorium Elektryczności i Magnetyzmu Głównego Urzędu Miar zaprojektowano, opracowano i wykonano czterozaciskowy kondensator wzorcowy o wartości 10 nF, z dielektrykiem ceramicznym. Kondensator został umieszczony w termostacie z wbudowanym elektronicznym układem sterowania, który zapewnia bardzo precyzyjne utrzymywanie określonej temperatury. Układ sterowania może być zasilany ze stacjonarnego źródła zasilania lub z dodatkowego akumulatora. Opracowany wzorzec charakteryzuje się bardzo dobrą stabilnością wartości pojemności elektrycznej dla danej częstotliwości oraz małą wartością stratności. Wzorzec ten jest niezbędnym elementem dla transferu jednostki miary pojemności elektrycznej z kwantowego efektu Halla.
EN
In Electricity and Magnetism Laboratory of the Central Office of Measures, a four-terminal reference capacitor 10 nF (with a ceramic dielectric) was designed, developed and made. The capacitor has been placed in a thermostat with a built-in electronic control system which can be powered from a stationary power source or from an additional battery. The developed standard is characterized by a very good stability of the capacitance value for a given frequency and a low loss value tan δ. This capacitor is a necessary element for the transfer of the unit of capacitance from the quantum Hall effect.
9
Content available Hall effects on isothermal vertical plate with uniform mass diffusion in the presence of rotating fluid and chemical reaction of first order
Dhananjeya Kumaar V. S. A., Muthucumaraswamy R.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 1
111--121
EN
An exact solution of the combined study of Hall effects on a vertical plate with a rotating fluid in the presence of a homogeneous chemical reaction of first order has been analysed. The dimensionless governing coupled partial differential equations are tackled using the usual Laplace transform technique. The sway of the Hall parameter, Hartmann number, Grashof number, Prandtl number, Schmidt number, chemical reaction parameter on the axial velocity and concentration of the fluid has been depicted graphically. When the non-dimensional angular velocity, Ω=2M21+m.2, the transverse velocity component vanishes, thereby the axial velocity of the fluid attains the maximum value. It is noted that with increase in the Hall parameter, thermal Grashof number and mass Grashof number, the axial velocity of the fluid increases significantly.
10
Content available Boundary layer flow of magneto-micropolar nanofluid flow with Hall and ion-slip effects using variable thermal diffusivity
Bilal M., Hussain S., Sagheer M.
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2017
|
Vol. 65, nr 3
383--390
EN
In the present article, magneto-micropolar nanofluid flow with suction or injection in a porous medium over a stretching sheet for the heat and mass transfer is analyzed numerically. Both Hall and ion-slip effects are considered along with variable thermal diffusivity. The governing partial differential equations are transformed to ordinary differential equations using usual similarity transformations. These coupled non-linear differential equations are solved using the shooting method. Effects of prominent parameter on velocities, temperature and concentration are discussed graphically. Numerical values of skin-friction coefficient, local Nusselt number and local Sherwood number are also tabulated and discussed.
11
Content available Przydatność wybranych systemów pomiaru odkształceń w badaniach trójosiowych słabych gruntów spoistych
Jastrzębska M., Kowalska M.
Budownictwo i Inżynieria Środowiska
|
2013
|
Vol. 4, no. 2
105--112
PL
W pracy przedstawiono najczęściej stosowane systemy służące do pomiaru małych odkształceń w badaniach trójosiowych: LVDT, czujniki wykorzystujące efekt Halla oraz czujniki zbliżeniowe. Omówiono ich przydatność w badaniach słabych gruntów spoistych ze szczególnym uwzględnieniem aspektów montażowych. Zaprezentowano również metodę tomografii RX jako alternatywę dla czujników lokalnych.
EN
The paper presents chosen small strain measuring systems that are the most commonly used in triaxial testing: LVDT, the Hall effect gauges and proximity transducers. Their applicability for soft cohesive soils, particularly in terms of assembly issues, is discussed. Computer tomography is also described as an alternative method for the local gauges.
12
Content available remote Hall effect on thermal stability of ferromagnetic fluid in the presence of suspended particles
Aggarwal A. K., Makhija S.
International Journal of Applied Mechanics and Engineering
|
2012
|
Vol. 17, no. 2
349-365
EN
This paper deals with the theoretical investigation of the effect of Hall currents and suspended particles on the thermal stability of a ferromagnetic fluid heated from below. For a fluid layer between two free boundaries, an exact solution is obtained using a linearized stability theory and normal mode analysis. A dispersion relation governing the effects of suspended particles and Hall currents is derived. For the case of stationary convection, it is found that the magnetic field has a stabilizing effect, whereas the suspended particles and Hall currents are found to have a destabilizing effect on the system. The critical Rayleigh numbers and wave numbers of the associated disturbances for the onset of stability as stationary convection are obtained. The principle of exchange of stabilities is not valid for the problem under consideration, whereas in the absence of Hall currents (hence magnetic field), it is valid under certain conditions.
13
Content available Peculiarities of quantum magnetotransport in In₀.₅₃Ga₀.₄₇As/In₀.₅₂Al₀.₄₈As heterostructures grown on (100) InP
Przesławski T.
Electron Technology : Internet Journal
|
2007
|
Vol. 39, nr 2
1-3
EN
Magnetotransport properties of the Si δ- doped In₀.₅₃Ga₀.₄₇As/In₀.₅₂Al₀.₄₈As heterostructures grown on (100)InP substrates were investigated by performing classical Van der Pauw Hall effect as well as high field quantum magnetotransport measurements. The results of the conventional Hall measurements are ambiguous because the mobility obtained at liquid helium occurred to be smaller than at room temperature. The qualitative analysis of the conductivity tensor revealed at least two conducting channels. Thus, the properties of whole structure are limited by the low mobility of the parasitic parallel conduction layer. On the other hand, the fast Fourier transform of the quantum magnetooscillations consists of a lot of frequencies. None of them can not be attributed to the presence of the two-dimensional electron gas (2DEG) in a single quantum well. We interpret our rich Fourier spectrum as due to quantum interference (QI) between open electron path commonly found in superlattices structures.
14
Content available remote Phase transitions in Co78Si9B13 and Fe78Si9B13 metallic glasses induced by isochronal annealing
Jakubczyk E.
Materials Science Poland
|
2006
|
Vol. 24, No. 4
1027--1036
EN
The crystallization process of Co78Si9B13 and Fe72Si9B13 metallic glasses was stimulated by isochronal annealing at various temperatures (573-823 K). By the DSC, X-ray diffraction, Hall and electrical resistivity measurements it was found that the crystallization proceeds through two main stages. At the first stage, alfa-Co and alfa-Fe phases are formed and at the second stage Co2B and Fe2B phases are crystallized. During the crystallization, the ferromagnetic ordering of both alloys is still conserved. Fe78Si 9B13 alloy has a much wider range of structural stability. The activation energy determined from DSC measurements and the total energy of the created phases obtained by quantum chemistry method confirmed the sequence and the type of the created phases. The creation of crystalline phases from the amorphous matrix was related to a distinct decrease of the electrical and Hall resistivities and the spontaneous Hall coefficient.
15
Content available remote Hall effect in strongly correlated electron systems
Tran V.H.
Materials Science Poland
|
2006
|
Vol. 24, No. 3
669--673
EN
This work provides a brieft survey of the Hall effect data collected on some strongly correlated electron systems. The experimental results illustrate the behaviour of heavy-fermion system UCu5Al, heavy-fermion semiconductor U2Ru2Sn, ferromagnetic sueperconductor under pressure UGe2, and ferromagnet with a 2D weak localization effect UCo0.5Sb2.
16
Content available remote Hall effects on MHD plasma Couette flow in a rotating environment
Ghosh S. K., Pop I.
International Journal of Applied Mechanics and Engineering
|
2004
|
Vol. 9, no 2
293-305
EN
The Magnetohydrodynamic (MHD) plasma Couette flow in a rotating frame of reference subject to the Hall current is studied. This problem is confined to a startup process, which deals with an impulsive start of the moving plate as well as an accelerated start of the moving plate. The solution is obtained by employing the Laplace inversion method. An asymptotic behavior of the solution is analysed for small as well as large time T to gain the physical insight into the flow pattern. As a consequence of the physical situation of interest the fully ionized neutral plasma interacts with the frictional layer when it starts in motion. The dimensionless velocity profiles are depicted graphically and the shear stresses are presented in tables.
17
Content available remote Hall effects on MHD low and heat transfer over a stretching surface
Gupta A. S., Pal A., Pal B., Takhar H. S.
International Journal of Applied Mechanics and Engineering
|
2003
|
Vol. 8, no 2
219-232
EN
A magnetohydrodynamic (MHD) flow of an incompressible viscous electrically conducting fluid over a stretching surface is investigated when the fluid is permeated by a uniform transverse magnetic field and Hall effects are taken into account. It is found that for a flow at small magnetic Reynolds number past the surface which is stretched with a velocity proportional to the distance from a fixed point, velocity profiles are similar. For a fixed value of the Hall parameter m, components of velocity along and normal to the surface at a given point decrease with an increase in the magnetic parameter M. However for fixed values of m and M, the cross-flow velocity component induced by Hall currents reaches a maximum value at a certain height from the surface and the profiles for this velocity component shift towards the left with an increase in M. A novel result of the analysis is that for a fixed value of M, the primary velocity component remains positive for small values of the Hall parameter (m=<0.5) and becomes negative for m>0.5 indicating flow reversal. The region of this flow reversal increases with an increase in m. A similarity solution for temperature distribution in the above flow is also found and the rate of heat transfer at the stretching surface is computed for various values of m and M.
18
Content available remote Hall effect on magnetohydrodynamic viscoelastic free convection flow with mass transfer through a porous medium near an infinite vertical porous plate
Eldabe N. T. M. N. T. M., Ghaly A. Y., Saddeek G., Hassan M. A.
Mechanics and Mechanical Engineering
|
2001
|
Vol. 5, nr 2
185-201
EN
The present study is devoted to investigate the influences of hall current on unsteady free convection flow of magnetohydrodynamic non-Newtonian viscoelastic incompressible fluid with mass transfer over an infinite vertical porous plate. The system is stressed by uniform magnetic field acting in a plane, which makes an angle α with the plane transverse to the plate over an infinite vertical porous plate. The Walter's model is used to characterize the non-Newtonian fluid behavior. Similarity solution for the transformed governing equations is obtained with prescribed variable suction velocity. Numerical results for the details of the velocity, temperature and concentration profiles are shown on graphs. Excess surface temperature as well as concentration gradient at the wall have been presented for different values of the elasticity parameter n0, magnetic parameter M, Schmidt number Sc, Grashof number Gr, modified Grashof number Gc, Hall parameter m, Dufour number Df, Soret number Sr and permeability parameter k*.
19
Content available remote Ułamkowy kwantowy efekt Halla
Stormer H.
Postępy Fizyki
|
2000
|
T. 51, z. 3
113-133
20
Badanie efektu Halla w izotropowych i anizotropowych stopach amorficznych na osnowie Co
Kolano R., Jakubczyk E.
Archiwum Nauki o Materiałach
|
1999
|
T. 20, nr 2
113-122
PL
Dla amorficznych stopów Co68Fe4Mo1,5Si13,5B13 i Co71,5Fe2,5Mn2Mo1Si9B13 badano efekt Halla, strukturę domenową oraz właściwości magnetyczne: indukcję magnetyczną nasycenia Bmax, pozostałość magnetyczną Br, koercję Hc i straty magnetyczne Ps. Badania prowadzono dla próbek wygrzewanych w temperaturze poniżej temperatury krystalizacji bez pola magnetycznego i w polu prostopadłym do kierunku odlewania taśmy, tj. dla próbek izotropowych i anizotropowych magnetycznie. Stwierdzono, że wyindukowana anizotropia zmienia strukturę domenową obu stopów oraz istotnie zmniejsza ich pozostałość magnetyczną, koercję i straty magnetyczne, powoduje wzrost rezystywności Halla i zmniejsza wartość indukcji magnetycznej, przy której następuje przejście z zakresu anomalnego do normalnego efektu Halla.
EN
Investigation of the correlation between the Hall effect, the domain structure and such magnetic properties as: saturation induction Bmax, magnetic remanence Br, coercivity Hc, and core losses Ps, were carried out for isotropic and anisotropic amorphous Co68Fe4Mo1,5Si13,5B13 and Co71,5Fe2,5Mn2Mo1Si9B13 alloys. The samples composed from the above alloys were annealed at a temperature below the crystallization temperature without magnetic field and in a magnetic field perpendicular to the ribbon casting direction. The magnetic anisotropy induced by the external transverse field caused changes of the domain structure in both alloys and a significant decrease of magnetic remanence, coercivity and core losses. Moreover, the increase of the Hall resistivity and the decrease of the value of the magnetic induction at a transition from the anomalous to the ordinary. Hall effect occurs was observed for anisotropic ribbons.
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