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Tytuł:
Magnetyzm środowiskowy : rodzaje wzbogacenia magnetycznego na przykładzie gleby inicjalnej skalistej i rankera
Environmental Magnetism : Type of Magnetic Enhancement on the Example of Lithosol and Ranker
Autorzy:
Szuszkiewicz, Marcin
Łukasik, Adam
Szuszkiewicz, Maria Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/1818542.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwa Geofizyczne
Tematy:
magnetyzm środowiskowy
wzbogacenia magnetyczne
potencjalnie toksyczne pierwiastki
environmental magnetism
magnetic enhancement
potentially toxic elements
Opis:
Celem niniejszej pracy było scharakteryzowanie źródeł pochodzenia cząstek magnetycznych na przykładzie gleby inicjalnej skalistej i rankera. Analiza rozkładów pionowych wybranych parametrów magnetycznych i geochemicznych prowadzona była w trzech profilach glebowych wytworzonych z/na różnym podłożu skalnym (serpentynicie, amfibolicie i granitoidzie). Prezentowane badania oparte zostały o wykorzystanie wybranych parametrów magnetycznych: podatność magnetyczna (χ) i jej zależność częstotliwościowa (χfd), wspartych przez analizy geochemiczne (określenie zawartości wybranych potencjalnie toksycznych pierwiastków (PTEs: Pb i Zn) oraz Fe, a także zastosowanie wskaźnika geoakumulacji (Igeo). Wyniki wskazują na wertykalną zmienność wartości χ w profilach glebowych, która także odzwierciedla stopień zmienności pozostałych parametrów. W przypadku geogenicznego wzbogacenia magnetycznego wysoka wartość podatności magnetycznej w poziomie mineralnym (przejściowym) AC wskazuje na dominującą rolę procesów wietrzenia i redystrybucji ferrimagnetycznych minerałów z podłoża skalnego (poziomu R) do wierzchnich poziomów gleby. Natomiast, pedogeniczne wzbogacenie magnetyczne związane było z podpoziomem organicznym Ofh, gdzie stwierdzona została obecność superparamagnetycznych cząstek. W odniesieniu do profilu wytworzonego z granitu, magnetyczny i geochemiczny sygnał w wierzchnim poziomie mineralnym (Ah) jest efektem wzbogacenia w technogeniczne cząstki magnetyczne (TMPs).
The primary aim of this study was to characterize the origin and nature of magnetic particles on the example of Lithosol and Ranker. Analyses of the vertical distribution of selected magnetic and geochemical parameters were conducted in three different soil profiles developed on various bedrock to describe the local conditions and factors affecting magnetic enhancement. Examined soil profiles represent two type of soils (one Brown Ranker and two Lithosol) developed from igneous – plutonic (granitoid) and metamorphic (amphibolite and serpentinite) rocks, respectively. The measured magnetic parameters include: volume (κ) and mass magnetic susceptibility (χ) as well as frequencydependent of magnetic susceptibility (χfd). Moreover, magnetic data were supported by geochemical measurement of the selected Potentially Toxic Elements (PTEs: Pb and Zn) and Fe content, and quantification of soil pollution parameter (i.e. Geoaccumulation Index – Igeo). The results show that the vertical variability of χ values in soil profiles results also in a high variability of other presented ‘parameters’. In the case of geogenic magnetic enhancement, the high magnetic susceptibility values measured in mineral (transitional) horizon AC indicated the predominant role of weathering processes together with the redistribution of ferrimagnetic minerals from bedrock (i.e. R horizon) to the topsoil. Whereas, the pedogenic magnetic enhancement was related to organic subhorizon Oea (in soil profile developed on amphibolite) and reflects the occurrence of ultra-fine superparamagnetic particles. Magnetic and geochemical signal in the topsoil horizon (i.e. Ah) of profile developed from granite cause the enhancement of Technogenic Magnetic Particles (TMPs), i.e. the increment of χ is accompanied with the high concentration of iron, lead and zinc.
Źródło:
Przegląd Geofizyczny; 2020, 3-4; 139--153
0033-2135
Pojawia się w:
Przegląd Geofizyczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artificial Magnetic Conductor-based Millimeter Wave Microstrip Patch Antenna for Gain Enhancement
Autorzy:
Belabbas, Khadidja
Khedrouche, Djamel
Hocini, Abdesselam
Powiązania:
https://bibliotekanauki.pl/articles/1839484.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
artificial magnetic conductor
gain enhancement
microstrip patch antenna
millimeter wave
reection phase
Opis:
In this paper, a small (20 × 20 × 2.4 mm) loaded microstrip patch antenna (MPA) with an asymmetric artificial magnetic conductor (AMC) as a ground plane is designed for millimeter wave applications. Two AMC structures are proposed; one has the property of a 0 ◦ reflection phase around 28.4 GHz, with a symmetric geometry, which makes the reflection phase insensitive to variations in both polarization and incident angle. This symmetric AMC structure ensures angular stability which is considered as a major requirement when periodic structures are used as antenna ground planes. The other structure is characterized by an asymmetric geometry and shows an interesting behavior around 28.6 GHz, where a discontinuity in the reflection phase appeared due to the fact that surface impedance nature changed from purely capacitive to purely inductive. This paper studies the effects of the two proposed AMC structures on the performance of MPAs, by using an array of 8 × 8 unit cell elements as an artificial ground plane. Simulation results show that an MPA with a symmetric AMC ground plane offers better impedance matching and a wider bandwidth. Compared with conventional MPAs, gain is enhanced and directivity is improved as well. As far as an MPA with an asymmetric AMC ground plane is concerned, its performance in terms of gain and directivity is higher than that of the conventional solution.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 56-63
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artificial Magnetic Conductor-based Millimeter Wave Microstrip Patch Antenna for Gain Enhancement
Autorzy:
Belabbas, Khadidja
Khedrouche, Djamel
Hocini, Abdesselam
Powiązania:
https://bibliotekanauki.pl/articles/1839467.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
artificial magnetic conductor
gain enhancement
microstrip patch antenna
millimeter wave
reection phase
Opis:
In this paper, a small (20 × 20 × 2.4 mm) loaded microstrip patch antenna (MPA) with an asymmetric artificial magnetic conductor (AMC) as a ground plane is designed for millimeter wave applications. Two AMC structures are proposed; one has the property of a 0 ◦ reflection phase around 28.4 GHz, with a symmetric geometry, which makes the reflection phase insensitive to variations in both polarization and incident angle. This symmetric AMC structure ensures angular stability which is considered as a major requirement when periodic structures are used as antenna ground planes. The other structure is characterized by an asymmetric geometry and shows an interesting behavior around 28.6 GHz, where a discontinuity in the reflection phase appeared due to the fact that surface impedance nature changed from purely capacitive to purely inductive. This paper studies the effects of the two proposed AMC structures on the performance of MPAs, by using an array of 8 × 8 unit cell elements as an artificial ground plane. Simulation results show that an MPA with a symmetric AMC ground plane offers better impedance matching and a wider bandwidth. Compared with conventional MPAs, gain is enhanced and directivity is improved as well. As far as an MPA with an asymmetric AMC ground plane is concerned, its performance in terms of gain and directivity is higher than that of the conventional solution.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 56-63
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review on active techniques in microchannel heat sink for miniaturization problem in electronic industry
Autorzy:
Bhandari, Prabhakar
Singh, Jarnail
Kumar, Kaushal
Ranakoti, Lalit
Powiązania:
https://bibliotekanauki.pl/articles/2175199.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
microchannel heat sink
active technique
electrostatic force
flow pulsation
magnetic field
heat transfer enhancement
radiator mikrokanałowy
siła elektrostatyczna
pulsacja przepływu
pole magnetyczne
wymiana ciepła
Opis:
With continuous miniaturization of modern electronic components, the need of better cooling devices also keeps on increasing. The improper thermal management of these devices not only hampers the efficiency but can also cause permanent damage. Among various techniques, microchannel heat sink has shown most favourable performance. To further enhance the performance, two techniques i.e., active and passive are used. In passive technique, no external power source is required like heat sink design alteration and working fluid modification. External power source is necessary for heat transfer augmentation in the microchannel heat sink when using the active approach. Due to compact size of microchannel, active techniques are not used more often. However, the present work highlights the different active technique used in microchannel i.e., Electrostatic forces, flow pulsation, magnetic field, acoustic effects, and vibration active techniques. Above mentioned techniques have been analysed in detail.
Źródło:
Acta Innovations; 2022, 45; 45--54
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ stałego pola magnetycznego na przemiany związków azotu w biologicznym złożu tarczowym
Impact of a Static Magnetic Field on Nitrogen Compounds Transformations in a Rotating Biological Contactor
Autorzy:
Rodziewicz, J.
Filipkowska, U.
Janczukowicz, W.
Kłodowska, I.
Prażmo, M.
Powiązania:
https://bibliotekanauki.pl/articles/1819013.pdf
Data publikacji:
2013
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
pole magnetyczne
przemiany związków azotu
electrolytically-aided denitrification
ammonium-rich leachate
wastewater treatment
aerobic rbc biofilm
simultaneous carbon
activated sludge
removal
wastewaters
enhancement
reactor
magnetic field
Opis:
The processes of nitrification and denitrification are the most common and well-known methods of biological nitrogen removal from wastewater. Nitrifying bacteria are characterized by a low growth rate, a tendency to wash out from the reactors, which means that nitrification is the limiting factor in the course of the nitrogen compounds removal process. Therefore, it is necessary to keep a large amount of nitrifying biomass in reactors in order to ensure the proper level of nitrification efficiency. Previously performed researches have shown that the magnetic field can affect the growth of microorganisms and their ability to biodegrade contaminants. Application of a magnetic field enhances microbial activity, accelerates degradation of organic compounds and increases nitrification rate. Otherwise the magnetic field is beneficial for biomass biodiversity and abundance. The aim of this study was to determine the effect of magnetic field on the efficiency of organic compounds removal and nitrogen compounds transformations taking place in the biomass of rotating biological contactor. Investigations were carried out in a rotating biological contactor (RBC) working in a bench scale. Each section containedpackets of disks with a diameter of 0.22 m submerged in a semi-circular tank with a capacity of 2 L. Submergence of the disks was 40%. Disks rotated with speed of 60 rpm. The study was carried out using four RBCs – the first one was called the control unit, next three were under the influence of the magnetic field of 60 mT, 120 mT and 180 mT induction. Studies have shown that the efficiency of nitrification increased with growth ofmagnetic field induction. The magnetic field of 180 mT intensity increased nitrification efficiency significantly different, when compared with other systems, and was equal to 92%. Denitrification efficiency was the highest in the system, where the biomass was exposed to the magnetic field of 60 mT induction. Process efficiency decreased with increasing magnetic induction. Exposure of wastewaters and biofilm biomass in the magnetic field did not affect the statistical efficiency of the organic compounds removal. The highest percentage of COD biodegradation, on average 89.51%, was observed in a rotating biological contactor exposed to magnetic field of the highest tested induction.
Źródło:
Rocznik Ochrona Środowiska; 2013, Tom 15, cz. 2; 1511-1524
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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