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Wyszukujesz frazę "air flux" wg kryterium: Temat


Tytuł:
Influence of air assistance on spray coverage of wheat
Autorzy:
Gajtkowski, A
Powiązania:
https://bibliotekanauki.pl/articles/65656.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spraying quality
plant coverage
air sleeve
plant spraying
air flux
wheat
coverage
winter wheat
Air Plus Spridotrain sprayer
Opis:
The purpose of applying an additional air flux in field sprayers is limiting liquid drift. The tlux also influences the quality of plant spraying. Air Plus Spridotrain sprayer, produced by RAU company, was applied in the research on the influence of air flux on the quality of coverage of winter wheat (Roma variety). The plant coverage was determined using water sensitive papers.
Opryskiwacze polowe wyposażane są w rękawy powietrzne w celu zmniejszenia znoszenia cieczy na sąsiednie pola. Zmiana wydatku dodatkowego strumienia powietrza z rękawa ma również wpływ na jakość opryskiwania roślin. Do badań zastosowano opryskiwacz AirPlus firmy RAU wyposażony w rozpylacze wirowe ConeJet TXVK-10. Opryskiwano pszenicę odmiany Roma. Analiza wyników badań wskazuje na wpływ wydatku dodatkowego strumienia powietrza. Im wyższa dawka cieczy na hektar, tym lepsza jakość pokrycia liści pszenicy. Najwyższą wartość stopnia pokrycia powierzchni liści uzyskuje się przy dawce 403 l/ha i średnim ustawieniu wydatku powietrza (ponad 80%).
Źródło:
Journal of Plant Protection Research; 2001, 41, 4
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental analysis of linear induction motor under variable voltage variable frequency (VVVF) power supply
Autorzy:
Wakode, P. D.
Tariq, M.
Bhattacharya, T. K.
Powiązania:
https://bibliotekanauki.pl/articles/136237.pdf
Data publikacji:
2016
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
Linear Induction Motor
Variable Voltage Variable Frequency
experimental
air gap flux density
Opis:
This paper presents the complete analysis of Linear Induction Motor (LIM) under VVVF. The complete variation of LIM air gap flux under ‘blocked Linor’ condition and starting force is analyzed and presented when LIM is given VVVF supply. The analysis of this data is important in further understanding of the equivalent circuit parameters of LIM and to study the magnetic circuit of LIM. The variation of these parameters is important to know the LIM response at different frequencies. The simulation and application of different control strategies such as vector control thus becomes quite easy to apply and understand motor’s response under such strategy of control.
Źródło:
Transactions on Environment and Electrical Engineering; 2016, 1, 2; 18-24
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fully Automated System for Air Velocity Profile Measurement
Automatyczny system do wyznaczania profilu prędkości dla strumienia powietrza
Autorzy:
Kabaciński, M.
Pawliczek, R.
Powiązania:
https://bibliotekanauki.pl/articles/139559.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air flux measurement
flowmeter
stepper engine drive
virtual instruments
pomiar przepływu powietrza
miernik przepływu
napęd silnika krokowego
przyrządy wirtualne
Opis:
The paper presents the idea of a system for controlling the movement of a flowmeter for air velocity profile measurement. In such a system, due to massive amount of data and limitations of the Data Acquisition Equipment, it is necessary to use moveable sensors. The flowmeter sensor is moved with the use of a linear module with a stepper motor and a tooth-belt drive. The location and speed of the sensor are controlled by a program based on the idea of virtual instrument. The proposed structure allows the user to control operation of the stand and provides automatic measurement. A wide range of velocity and step increments of the stepper motor drive, and flexibility of the virtual instrument software, allow one to create effective measurement systems ensuring sufficiently precise location with optimal time duration of measurement. It is shown that the linear module with tooth-belt is an effective alternative for similar modules with micro-screw drives.
W artykule zaprezentowano system kontroli przemieszczenia przyrządu do pomiaru profilu prędkości strumienia powietrza. W takich systemach z powodu dużej liczby punktów pomiarowych oraz ograniczeń wynikających z urządzeń do akwizycji danych konieczne jest przemieszczanie elementu pomiarowego. Czujnik przepływu jest przesuwany za pomocą modułu liniowego z napędem w postaci paska zębatego i silnika krokowego. Położenie i prędkość czujnika jest kontrolowane za pomocą autorskiego oprogramowania bazującego na idei tzw. „przyrządów wirtualnych”. Układ kontolno-pomiarowy pozwala operatorowi na obsługę stanowiska oraz automatyczne przeprowadzenie pomiarów. Szeroki zakres prędkości obrotowej i dużej rozdzielczości napędu w postaci silnika krokowego oraz elastyczność oprogramowania pozwala tworzyć efektywny system pomiarowy zapewniający dostatecznie dokładną lokalizację punktów pomiarowych przy optymalnym czasie pomiarów. Wykazano, ze napęd liniowy z zastosowaniem paska zębatego i silnika krokowego może być efektywną alternatywą dla podobnych urządzeń ze śruba napędową.
Źródło:
Archive of Mechanical Engineering; 2012, LIX, 4; 435-451
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a rotor with a starter-generator integrated into an aero car
Autorzy:
Wu, Zaixin
Yu, Ruiguang
Powiązania:
https://bibliotekanauki.pl/articles/141579.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aero motor
air-gap flux density
axial segmentation
electromagnetic and heat flux coupling
Halbach array structure
Opis:
The Halbach array structure rotor of the aero motor can satisfy the requirements of high power density and high air-gap flux for aeronautical motors. The size parameters of the rotor are determined by the power rating of the motor based on an analytic method. Producing a Halbach array structure is difficult. Comparison and analysis of the structure of the aero motor showthat the overall structure of the rotor adopts a three-axial-section classic Halbach-array hollow structure, and the rotor magnetic steel adopts a discrete structure of 4 blocks per pole and a single 45◦ magnetisation mode, which reduces the processing difficulty of the rotor magnetic steel. The finite element method was used to analyse the magnetic flux density distribution of the aeronautical motor under various working conditions. The results show that the motor can produce uniform air-gap flux density at various working conditions and present good sinusoidal periodicity. Furthermore, the axial segment did not produce obvious magnetic flux leakage. Finally, considering the eddy current loss of the stator under the rated power-generation condition with high-frequency magnetic field, we conducted coupling analysis of electromagnetic and heat flows to verify that the thermal characteristics of the rotor magnetic steel material could meet the requirements for the aero motor.
Źródło:
Archives of Electrical Engineering; 2019, 68, 2; 357-371
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the influence of driving harmonic on electromagnetic field and temperature field of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Yu, W.
Li, Y.
Yang, C.
Powiązania:
https://bibliotekanauki.pl/articles/141535.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air gap flux density
eddy current loss
harmonic
magnetic field decoupling
torque ripple
Opis:
At present, the drivers with different control methods are used in most of permanent magnet synchronous motors (PMSM). A current outputted by a driver contains a large number of harmonics that will cause the PMSM torque ripple, winding heating and rotor temperature rise too large and so on. In this paper, in order to determine the influence of the current harmonics on the motor performance, different harmonic currents were injected into the motor armature. Firstly, in order to study the influence of the current harmonic on the motor magnetic field, a novel decoupling method of the motor magnetic field was proposed. On this basis, the difference of harmonic content in an air gap magnetic field was studied, and the influence of a harmonic current on the air gap flux density was obtained. Secondly, by comparing the fluctuation of the motor torque in the fundamental and different harmonic currents, the influence of harmonic on a motor torque ripple was determined. Then, the influence of different current harmonics on the eddy current loss of the motor was compared and analyzed, and the influence of the drive harmonic on the eddy current loss was obtained. Finally, by using a finite element method (FEM), the motor temperature distribution with different harmonics was obtained.
Źródło:
Archives of Electrical Engineering; 2017, 66, 2; 295-312
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis and comparison of PMSM with concentrated winding and distributed winding
Autorzy:
Qiu, Hongbo
Zhang, Yong
Yang, Cunxiang
Yi, Ran
Powiązania:
https://bibliotekanauki.pl/articles/141179.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air-gap flux density
cogging torque
concentrated winding
distributed winding
efficiency
loss
PMSM
Opis:
The concentrated winding (CW) is obviously different from the traditional distributed winding (DW) in the arrangement of windings and the calculation of winding factors, which will inevitably lead to different performances of the permanent magnet synchronous motor (PMSM). In order to analyze the differences between the CW and the DW in the performance, a 3 kW, 1500 r/min PMSM is taken as an example to establish a 2-D finite element model. The correctness of the model is verified by comparing experimental data and calculated data. Firstly, the finite element method (FEM) is used to calculate the electromagnetic field of the PMSM, and the performance parameters of the PMSM are obtained. On this basis, the influences of the two winding structures on the performance are quantitatively analyzed, and the differences between the two winding structures on the performance of the PMSM will be determined. Finally, the differences of efficiency between the two winding structures are obtained. In addition, the influences of the winding structures on eddy current loss are further studied, and the mechanism of eddy current loss is revealed by studying the eddy current density. The analysis of this paper provides reference and practical value for the optimization design of the PMSM.
Źródło:
Archives of Electrical Engineering; 2020, 69, 2; 303-317
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of different rotor magnetic circuit structure on the performance of permanent magnet synchronous motor
Autorzy:
Qiu, H.
Yu, W.
YANG, C.
Yi, R.
Powiązania:
https://bibliotekanauki.pl/articles/141061.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air gap flux density
cogging torque
magnetic circuit structure
overload capacity
permanent magnet synchronous motor
Opis:
In order to compare the performance difference of the permanent magnet synchronous motors (PMSM) with different rotor structure, two kinds of rotor magnetic circuit structure with surface-mounted radial excitation and tangential excitation are designed respectively. By comparing and analyzing the results, the difference of the motor performance was determined. Firstly, based on the finite element method (FEM), the motor electromagnetic field performance was studied, and the magnetic field distribution of the different magnetic circuit structure was obtained. The influence mechanism of the different magnetic circuit structure on the air gap flux density was obtained by using the Fourier theory. Secondly, the cogging torque, output torque and overload capacity of the PMSM with different rotor structure were studied. The effect mechanism of the different rotor structure on the motor output property difference was obtained. The motor prototype with two kinds of rotor structure was manufactured, and the experimental study was carried out. By comparing the experimental data and simulation data, the correctness of the research is verified. This paper lays a foundation for the research on the performance of the PMSM with different magnetic circuit structure.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 583-594
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modal-frequency spectrum of magnetic flux density in air gap of permanent magnet motor
Autorzy:
Witczak, P.
Kubiak, W.
Lefik, M.
Szulakowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/140681.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electromagnetic fields
waves permanent magnet machines
air gap magnetic flux
spectral analysis
finite element method
Opis:
The classic relationships concerning the harmonic content in the air gap field of three-phase machines are presented in form of series of rotating waves. The same approach is applied to modeling of permanent magnet motors with fractional phase windings. All main reasons of non-sinusoidal shape of flux density distribution, namely, magnets’ shape and their placement, slotting, magnetic saturation and eccentricity are also related to their counterparts in modal-frequency spectrum. The Fourier 2D spectrum of time-stepping finite element solution is confronted with results of measurements, with special attention paid to accuracy of both methods.
Źródło:
Archives of Electrical Engineering; 2014, 63, 1; 29-46
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A model-measurements comparison of atmospheric forcing and surface fluxes of the Baltic Sea
Autorzy:
Rudolph, C.
Lehmann, A.
Powiązania:
https://bibliotekanauki.pl/articles/48268.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coupled sea-ice-ocean model
surface flux
temperature
pressure
radiation flux
heat flux
air-sea interaction
Baltic Sea
wave radiation
Opis:
Observed basic meteorological quantities, heat and radiation fluxes from three different measurement stations in the Baltic Sea are compared with model data of the coupled sea-ice-ocean model BSIOM in order to evaluate the atmospheric forcing, corresponding surface fluxes and the sea surface response. Observational data weremade available from the BASIS winter campaigns in 1998 and 2001 as well as from the r/v ‘Alkor’ cruise in June 2001. Simulated fluxes were calculated from prescribed atmospheric forcing provided from the SMHI meteorological database and modelled sea surface temperatures. The comparison of these fluxes with observations demonstrates a strong correlation, even though mean differences in sensible heat fluxes range from 4 to 12 W m−2 in winter and −25 W m−2 in the June experiment. Differences in latent heat fluxes range from −10 to 23 W m−2. The short-wave radiation flux used as model forcing is on average 15 W m−2 less than the corresponding observations for the winter experiments and 40 W m−2 for the June experiment. Differences in net long-wave radiation fluxes range from −5 to 12W m−2 in winter and −62W m−2 for the June experiment. The correspondence between measured and calculated momentum fluxes is very high, which confirms the usability of our model component for calculating surface winds and wind stresses from the atmospheric surface pressure.
Źródło:
Oceanologia; 2006, 48, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soil heat flux and air temperature as factors of radon (Rn-222) concentration in the near-ground air layer
Autorzy:
Podstawczyńska, A.
Pawlak, W.
Powiązania:
https://bibliotekanauki.pl/articles/971505.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
air temperature
Central Poland
exponential function
Rn-222
soil heat flux
Opis:
A unique, highly time-resolved, and synchronous three-year dataset of near-surface atmospheric radon-222 as well as soil heat flux and air temperature measurements at two sites (rural and urban) in Central Poland are investigated. The recognition of temporal variability of Rn-222 and selected meteorological variables in the urban and rural areas served to create two statistical models for estimation of this radionuclide concentration at 2 m a.g.l. The description of the relationships between the variables for individual months was established on the basis of an exponential function and an exponential function with time derivative of predictor to account for the hysteresis issue. The model with time derivative provided better results. The weakest fitting of modelled data to empirical ones is observed for the winter months. During subsequent seasons, air temperature as well as QG-driven (soil heat flux) models exhibited very high agreement with the empirical data (MBE, RMSE, MAE, and ‘index of agreement’ by Willmott were used to evaluate the models). A restriction in the use of QG for Rn-222 concentration was observed only in winter in the case of snow cover occurrence, which reduces the daily QG variability. A unique, highly time-resolved, and synchronous three-year dataset of near-surface atmospheric radon-222 as well as soil heat flux and air temperature measurements at two sites (rural and urban) in Central Poland are investigated. The recognition of temporal variability of Rn-222 and selected meteorological variables in the urban and rural areas served to create two statistical models for estimation of this radionuclide concentration at 2 m a.g.l. The description of the relationships between the variables for individual months was established on the basis of an exponential function and an exponential function with time derivative of predictor to account for the hysteresis issue. The model with time derivative provided better results. The weakest fitting of modelled data to empirical ones is observed for the winter months. During subsequent seasons, air temperature as well as QG-driven (soil heat flux) models exhibited very high agreement with the empirical data (MBE, RMSE, MAE, and ‘index of agreement’ by Willmott were used to evaluate the models). A restriction in the use of QG for Rn-222 concentration was observed only in winter in the case of snow cover occurrence, which reduces the daily QG variability.
Źródło:
Nukleonika; 2016, 61, 3; 231-237
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effektivnost' infrakrasnykh vodjanykh otopitel'nykh panelejj
Water efficiency infrared heating panels
Autorzy:
Cherednik, A.
Redko, A.
Powiązania:
https://bibliotekanauki.pl/articles/76786.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
water management
radiant heating
flux density
air temperature
heat flow
experimental study
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2014, 16, 6
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of vertical coarse aerosol fluxes in the boundary layer over the Baltic Sea
Autorzy:
Petelski, T.
Markuszewski, P.
Makuch, P.
Jankowski, A.
Rozwadowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/48277.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
aerosol flux
sea aerosol
wind speed
air-sea interaction
marine boundary layer
aerosol concentration
Baltic Sea
Źródło:
Oceanologia; 2014, 56, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ozone effects on trees, where uptake and detoxification meet
Autorzy:
De, Temmerman L
Vandermeiren, K.
D'Haese, D.
Bortier, K.
Asard, H.
Ceulemans, R.
Powiązania:
https://bibliotekanauki.pl/articles/41371.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
air pollutant
ozone effect
oxidative defence
detoxification
ozone
critical level
tree
ozone concentration
effective ozone flux
Opis:
Ozone is the most important air pollutant and its concentration in ambient air is still rising. Ozone concentrations measured at reference height (50 m is EMEP ozone modelling height), do not reflect the real concentration at the top of the vegetative canopy and do not provide sufficient information about the ozone fluxentering the leaves. Modelling stomatal conductance is leading to estimations of cumulative ozone uptake and enables much better to evaluate the impact of ozone on trees. The negative impact of ozone exposure has a measurable effect on physiological processes such as stomatal conductance, photosynthesis and respiration. Disturbance of the basic physiological processes is leading to growth and wood production losses. There have been several attempts to establish critical levels (CL) for ozone effects on forest trees. Average concentrations and cumulative exposure indices are satisfactory to some extent, but do not fully describe the potential impact of ozone exposure. Much more promising is an evaluation based on the effective ozone flux, which is a function of the absorbed ozone flux and the defensive response. Ozone uptake takes place primarily through the stomata and reactions of ozone with hydrocarbons released by the plant cells and transformations of dissolved ozone in the apoplastic fluid create many reactive oxygen species of which free radicals are able to initiate membrane lipid peroxidation and destruction of cell membranes. The defence of a plant against absorbed ozone starts in the apoplastic fluid. Ascorbate is believed to be a very important radical scavenger avoiding detrimental effects of reactive oxygen species to the membranes. Other important antioxidants are phenolics. The defensive response can be linked to the abundance of ascorbate or the ability of the plants to regenerate (reduce) ascorbate from monodehydroascorbate and dehydroascorbate. The reduction of dehydroascorbate takes place in the symplast where ascorbate can be transported back through the plasma membrane into the apoplast. Ozone exposure also causes oxidative stress of the plant cell interior by the formation of reactive oxygen species. Plants can cope with those toxic substances in the symplast by using antioxidants such as ascorbate, -tocopherol, glutathione and carotenoids and enzymes such as superoxide dismutases, catalases and several peroxidases. The complexity of the apoplastic and symplastic antioxidative capacity with different turnover rates and transport of antioxidants makes it difficult to determine the total antioxidative power.
Źródło:
Dendrobiology; 2002, 47
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water column conditions in a coastal lagoon near Jeddah, Red Sea
Autorzy:
Albarakati, A.M.A.
Ahmad, F.
Powiązania:
https://bibliotekanauki.pl/articles/48751.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
water column
coastal lagoon
Red Sea
heat balance
air-sea interface
stratification
wind stress
heat flux
bottom topography
Źródło:
Oceanologia; 2012, 54, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of calculation of air temperature in the open air layer
Metoda obliczania temperatury powietrza w otwartej warstwie powietrznej
Autorzy:
Piotrowski, J.Z.
Olenets, M.
Starzomska, M.
Zaborek, R.
Powiązania:
https://bibliotekanauki.pl/articles/402493.pdf
Data publikacji:
2012
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
open air layer
thermal performance
mathematical model
convective heat flux
radiant heat flux
heat transfer
otwarta warstwa powietrzna
wydajność cieplna
model matematyczny
konwekcyjny strumień ciepła
radiacyjny strumień cieplny
wymiana ciepła
Opis:
The building envelopes with the open air layer are common in building energy-efficient houses. In such buildings, air gap is used for moisture elimination from a surface of external wall, which improves its thermal properties. To improve the thermal quality of building envelopes with open air layer and reduce the heat transfer rate during the cold period, it is necessary to conduct more in-depth study of heat exchange in the ventilated layer of air. The article presents a mathematical model of heat transfer through building envelopes with an open air layer for the cold season. In the proposed mathematical model connective and radiant heat fluxes were considered separately.
Źródło:
Structure and Environment; 2012, 4, 4; 43-48
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł

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