scholarly journals Features of the Propagation of Microwave Radiation in a Freshwater Ice Cover

2021 ◽  
Vol 16 (3) ◽  
pp. 59-68
Author(s):  
Gurulev Aleksandr A. ◽  
◽  
Tsyrenzhapov Sergey V. ◽  
Kharin Yuriy V. ◽  
Kazantsev Vyacheslav A. ◽  
...  
Keyword(s):  
Microwave Radiation ◽  
Meteorological Parameters ◽  
Stokes Parameter ◽  
Radiation Power ◽  
Ice Cover ◽  
Stokes Parameters ◽  
Temperature Deformation ◽  
Microwave Range ◽  
Transmitted Radiation ◽  
Temperature Deformations

When scanning fresh ice cover in the microwave range at a frequency of 13 GHz, the transmitted radiation power was investigated at four linear polarizations (vertical, horizontal, and polarizations rotated at an angle of +-45) for a long period of time. The measurements were carried out on the ice cover of the lake. Arakhley (Transbaikal region) at a distance of 120 m from the coast in March 2021. We also measured the external parameters of the studied environment, namely, the temperature of the ice cover, meteorological parameters (wind speed, air temperature, pressure). The distance between the generator and the receiver of electromagnetic radiation was 40 meters. The orientation of the instruments is West-East. As a result, variations in the power of the transmitted microwave radiation were detected. These variations are related to the temperature deformations of the ice cover, which were recorded using a deformation sensor installed in the ice cover. Also revealed a feature that was observed earlier in the spring. This is a different temporal behavior of the first Stokes parameter, which is determined by the sum of the powers of two orthogonal polarizations, namely, the sum of the received signals at the vertical and horizontal polarizations, and the sum of the received signals of the two polarizations rotated at an angle of +45 and -45. This difference is also associated with temperature deformations of the fresh ice cover in the spring. Keywords: microwave range, fresh ice cover, Stokes parameters, temperature deformation

Influence of microwave processing on frame of films glues on an aqueous basis

2016 ◽  
Author(s):  
С.П. Исаев ◽  
К.А. Шевчук
Keyword(s):  
Electromagnetic Field ◽  
Microwave Radiation ◽  
Polyvinyl Acetate ◽  
Wood Quality ◽  
Microwave Processing ◽  
Phase Changes ◽  
Microwave Range ◽  
Adhesive Film ◽  
Modern Development ◽  
Experimental Researches

Современное развитие деревоперерабатывающей отрасли сопровождается существенным ростом объемов готовой продукции, производимой на основе клееной древесины. Качество выпускаемой клееной продукции во многом определяется свойствами применяемых клеев. Экспериментально исследовано влияние электромагнитного поля СВЧ-диапазона на структуру клеев, применяемых для склеивания древесины. Установлено, что СВЧ-обработка оказывает существенное влияние на микроструктуру поливинилацетатного клея Dorus 072. Структура клеевой пленки, обработанной СВЧ-излучением, имеет более высокую дисперсность, по сравнению с исходным полимером, которая выражается в среднем уменьшении глобул в 1,4 раза. Исследование фазового контраста пленки поливинилацетатного клея, обработанного СВЧ-излучением, позволило установить, что после обработки уменьшается фазовая неоднородность клеевой пленки и имеет место углубление дисперсности глобул полимера, приводящее к увеличению степени его упаковки с образованием однородной по структуре пленки. Экспериментальные исследования пленок карбамидоформальдегидного клея Dorus FU 406, подвергнутого СВЧ-обработке, показали, что структуры образцов пленок как обработанного, так и необработанного, клея не отличаются значительными изменениями. Исследование фазового сдвига по поверхности образца пленки карбамидоформальдегидного клея отражает распределение свойств материала и показывает, что СВЧ-обработка клея способствует образованию квазигомогенной структуры, формирование которой подтверждается уменьшением различий в границах фазовых переходов микроструктур отвержденного полимера. На основании проведенных экспериментов по исследованию структуры пленок клеев, применяемых для склеивания древесины, установлено, что в результате воздействия электромагнитного поля СВЧ-диапазона на клеевые растворы осуществляется нетепловая модификация, сопровождающаяся уменьшением размеров макромолекул полимера и формированием плотно упакованной структуры пленки. Полученные результаты позволяют сделать вывод о целесообразности дальнейших исследований по модификации клеев СВЧ-обработкой. Modern development of woodworking branches is accompanied by essential growth of volumes of the finished goods manufactured on the basis of glued wood. Quality of let out glued production in many respects is defined by properties of applied glues. Influence of an electromagnetic field of a microwave range on frame of the glues applied to coagglutination of wood is experimentally investigated. It is positioned that microwave processing makes essential impact on a microstructure of polyvinyl acetate glue Dorus 072. The frame of the adhesive film treated by microwave radiation, has higher dispersity in comparison with initial polymer which is expressed on the average reduction of globules in 1,4 times. Research of phase contrast of a film of the treated polyvinyl acetate glue by microwave radiation has allowed to position that after processing phase heterogeneity of an adhesive film decreases and the excavation of dispersity of globules of the polymer, leading to augmentation of degree of its packaging, forming an unimodal film on frame takes place. Experimental researches of films of amino-formaldehyde glue Dorus FU 406, subjected to microwave processing, have shown that Frames of samples of films both treated, and untreated glue do not differ significant changes. Research of phase alteration on a surface of the sample of a film of amino-formaldehyde glue reflects allocation of properties of a stuff and shows that glue microwave processing promotes formation of the quasi-homogeneous frame which formation proves to be true reduction of distinctions in borders of phase changes of microstructures hardning polymer. On the basis of the made experiments on research of frame of films of the glues applied to coagglutination of wood it is positioned that as a result of influence of an electromagnetic field of the microwave oven of a range on glutinous solutions not thermal modification accompanied by reduction of the dimensions of macromolecules of polymer and formation of densely packed frame of a film is carried out. The received results allow to draw a conclusion on expediency of the further researches on modification of glues by microwave processing.

scholarly journals Parametric Study on Microwave-Assisted Pyrolysis Combined KOH Activation of Oil Palm Male Flowers Derived Nanoporous Carbons

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2876
Author(s):  
Napat Kaewtrakulchai ◽  
Kajornsak Faungnawakij ◽  
Apiluck Eiad-Ua
Keyword(s):  
Microwave Radiation ◽  
Oil Palm ◽  
Radiation Power ◽  
Operating Time ◽  
Bet Surface Area ◽  
Koh Activation ◽  
Nanoporous Carbons ◽  
Microwave Assisted ◽  
Activating Agent ◽  
Male Flowers

Oil palm male flowers (PMFs), an abundant agricultural waste from oil palm plantation in Thailand, have been utilized as an alternative precursor to develop nanoporous carbons (NPCs) via microwave-assisted pyrolysis combined potassium hydroxide (KOH) activation. The influences of relevant processing variables, such as activating agent ratio, microwave power, and activation time on the specific pore characteristics, surface morphology, and surface chemistry of PMFs derived nanoporous carbons (PMFCs) have been investigated to explore the optimum preparation condition. The optimum condition under a microwave radiation power of 700 W, activation holding time of 6 min, and activating agent ratio of 2:1 obtained the PMFC with the highest Brunauer–Emmett–Teller (BET) surface area and total pore volume approximately of 991 m2/g and 0.49 cm3/g, composed of a carbon content of 74.56%. Meanwhile, PMFCs have a highly microporous structure of about 71.12%. Moreover, activating agent ratio and microwave radiation power indicated a significant influence on the surface characteristics of PMFCs. This study revealed the potential of oil palm male flowers for the NPCs’ production via microwave-assisted KOH activation with a short operating-time condition.

scholarly journals Modelling of the Magnetic Configuration of CP Stars from Polarimetric Observations

1998 ◽  
Vol 11 (2) ◽  
pp. 679-681
Author(s):  
M. Landolfi
Keyword(s):  
Magnetic Field ◽  
Stokes Parameter ◽  
Quadratic Field ◽  
Mean Field ◽  
Longitudinal Component ◽  
Stokes Parameters ◽  
Longitudinal Field ◽  
The Mean ◽  
The Magnetic Field ◽  
Polarized Radiation

The observational quantities commonly used to study the magnetic field of CP stars – the mean field modulus and the mean longitudinal field, as well as the ‘mean asymmetry of the longitudinal field’ and the ‘mean quadratic field’ recently introduced by Mathys (1995a,b) – are based either on the Stokes parameter / or on the Stokes parameter V. However, a complete description of polarized radiation requires the knowledge of the full Stokes vector: in other words, we should expect that useful information is also contained in linear polarization (the Stokes parameters Q and U); or rather we should expect the information contained in (Q, U) and in V to be complementary, since linear and circular polarization are basically related to the transverse and the longitudinal component of the magnetic field, respectively.

Radiothermal radiation of the ice cover of the Arakhley lake as a geo-indicator of changes in a water body

2020 ◽  
Vol 26 (7) ◽  
pp. 6-16
Author(s):  
V. Venslavsky ◽  
◽  
А. Orlov ◽  
Yu. Kharin ◽  
◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Water Body ◽  
Seasonal Variability ◽  
Crack Formation ◽  
Time Lag ◽  
Ice Cover ◽  
Anthropogenic Factors ◽  
Microwave Range ◽  
Ecological State ◽  
The Impact

The object of this study was the ecosystem of a water body; the subject was the radio-thermal radiation of the ice cover as a geo-indicator of changes in the ecological state of the Lake Arakhley. On the basis of a systematic approach, the work assessed the contribution of the seasonal variability of the properties of the ice cover to the intensity of radio-thermal radiation as a geo-indicator of the ecological system. At present, the influence of the ice cover deformation during the crack formation period on the intensity of radio-thermal radiation has not been sufficiently studied, which determined the relevance of an experimental study for use in problems of assessing anthropogenic factors of influence. The aim of the study was to measure the seasonal variability of the intensity of radio-thermal radiation as a background geo-indicator of the temperature regime and deformation of the ice cover during the crack formation period in the absence of direct anthropogenic factors. In January-March 2020, remote radio-physical methods were used to study the intensity of radio-thermal radiation of the microwave range for the test area of the ice cover of the Lake Arakhley during synchronous contact measurements of deformation and temperature in a niche at a depth of 40 cm from the surface. According to the data obtained, the reaction of the deformation sensor signal to daily temperature variations with a time lag of 1…3 hours was recorded. According to the results of the study, the correlation coefficient of the data of the ice deformation channel and the intensity of radio-thermal radiation in the range of 8…14 mm exceeded ± 0.7 (with a window of 1000 s), with the data of the temperature sensor in most areas exceeded ± 0.9. This proves the relationship between the temperature and deformation of the ice surface with the intensity of radio-thermal radiation, as a seasonal geo-indicator in determining the ecological state of the lake. The increments in the brightness temperature during the period of increased crack formation in the 14 mm channel, with a significant correlation with the deformation data, were about 3…6 K, which can also serve as a geo-indicator of seasonal changes in the properties of the ice cover. The results of the study were obtained in the absence of direct anthropogenic factors and are background geoindicators of the seasonal state of the ice cover during the period of temperature and dynamic loads during deformation and cracking, and in the future will be used in practice for correction in assessing the impact of anthropogenic factors

scholarly journals The V-Stokes Parameter as a Manifestation of Envelope Activity for Cool, Bright, Evolved Stars

1988 ◽  
Vol 108 ◽  
pp. 189-190
Author(s):  
B. D. Holenstein ◽  
R. H. Koch ◽  
R. J. Pfeiffer
Keyword(s):  
Radiation Field ◽  
Stokes Parameter ◽  
Stokes Parameters ◽  
Close Binaries ◽  
Evolved Stars

At Pennsylvania’s Flower and Cook Observatory, instrumentation has been developed to measure simultaneously the four Stokes parameters of the filtered radiation field from a celestial source. The instrumental Q/U/V-parameters have been found to be very small and well-behaved. Thus far, the program has concentrated on cool bright giants and supergiants and on hot, evolving close binaries. A single season’s investigation of Alp Ori has already been reported (Holenstein 1987) and the present paper is a summary of current results for the cool, evolved program stars.For Psi1 Aur, V CVn, 6 Gem, 72 Leo and 119 Tau no V-signal at the level of 3σhas been detected from data from the 1986-1987 season. At the level of 0.0n%, unambiguous and variable V-signals have been detected for VV Cep, Mu Cep, Alp Her, Alp Ori, Bet Peg, and Alp Sco.

A Novel Deduction of Stokes Parameters Based on 2-ordered Basis Matrices

2014 ◽  
Vol 556-562 ◽  
pp. 3598-3601
Author(s):  
Jin Zu Ji
Keyword(s):  
Electromagnetic Wave ◽  
Complex Number ◽  
Coordinate Transformation ◽  
Stokes Parameter ◽  
The Other ◽  
Stokes Parameters ◽  
Algebra Structure ◽  
Wave Polarization ◽  
Matrix Operation ◽  
Matrix Problems

Four two-ordered basis matrices were introduced to deduct Stokes parameter representing electromagnetic wave polarization. Two of them have algebra features similar to unity and imaginary of complex number, so an exponential function was defined which can easily express some matrix operation such as coordination rotation in 2-dimension. The other 2 basis matrices were also incorporated to deduce the Stokes parameters. The four matrices have some fatigue algebra structure which was incorporated in deduction. The coordinate transformation was converted to some matrix problems and we get a more concise result.

Synthesis and Study of Nanostructures Via Microwave Heating

2004 ◽  
Vol 821 ◽  
Author(s):  
Oxana V. Kharissova ◽  
Eder Zavala ◽  
Ubaldo Ortíz ◽  
Jorge L. Hernández-Piñero ◽  
Stanislav Soloviev
Keyword(s):  
Carbon Nanotubes ◽  
Microwave Heating ◽  
Microwave Radiation ◽  
Radiation Power ◽  
High Vacuum ◽  
Significant Proportion ◽  
Fused Silica ◽  
Silicon Substrates ◽  
Condensed Material ◽  
Silicon Based

AbstractThis work is devoted to microwave heating of graphite, sucrose, calcined sucrose, and a mixture of graphite with sucrose to produce carbon nanotubes (CNT's). The samples were submitted to microwave radiation (power 800W, frequency 2.45 GHz) in air and high vacuum (10−5Torr) for 30 – 60 min. The oven temperature was approximately 1200°C. After vaporization the condensed material was collected on various fused silica targets (different morphologies were used). The samples were found to contain a significant proportion of nanotubes, nanoparticles and fibers (1-2.8 micrometers), which appeared to be highly graphitized and helical structured. After deposition, the morphology of carbon nanotubes was studied with SEM, TEM and AFM techniques. It was observed that multi-walled nanotubes (MWNT's) were produced by this method. The morphology of fused silicon based substrates (SiO2, SiC) was studied as an important factor for the growth of carbon nanotubes. Many aspects as the size and shape of the obtained nanotubes on different substrates (porous and non-porous fused silicon substrates) were achieved, as well as the concentration of them across the substrate and other properties.

Temperature Deformation Analysis of CRTS II Ballastless Slab Track

2013 ◽  
Author(s):  
Chunfa Zhao ◽  
Xiaolin Song ◽  
Xiaojia Zhu
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Precast Concrete ◽  
Extreme Temperature ◽  
Temperature Deformation ◽  
Deformation Analysis ◽  
High Speed Trains ◽  
Temperature Deformations ◽  
Cohesive Zone Elements ◽  
Track Slab

Two finite element models of CRTS II ballastless track superstructure were developed to simulate temperature deformations of the precast concrete track slab. One of the models considered the fully bonding interface between the track slab and the cement asphalt mortar layers, while the other uses cohesive zone elements to simulate possible interfacial separation and slip. Warp deformations of the track slab under various temperature loads were calculated using both models. Numerical results show that the track slab glued fully to the mortar layers can approximately hold regular geometry shape even if it bears extreme temperature gradient loads. Although deteriorated mortar layers could increase significantly temperature deformations of the track slab, warp deformations of the track slab are still quite small and the rail harmonic irregularities due to the temperature deformations are tiny. It can be concluded that temperature deformations of CRTS II track slab have little effect on running safety and ride comfort of high-speed trains.

scholarly journals RETRIEVAL OF AEROSOL PHASE FUNCTION AND POLARIZED PHASE FUNCTION FROM POLARIZATION OF SKYLIGHT FOR DIFFERENT OBSERVATION GEOMETRIES

2018 ◽  
Vol XLII-3 ◽  
pp. 857-863
Author(s):  
L. Li ◽  
L. L. Qie ◽  
H. Xu ◽  
Z. Q. Li
Keyword(s):  
Zenith Angle ◽  
Phase Function ◽  
Solar Zenith Angle ◽  
Stokes Parameter ◽  
Principal Plane ◽  
Stokes Parameters ◽  
Retrieval Algorithm ◽  
Optical Parameters ◽  
Skylight Polarization ◽  
Observation Geometry

The phase function and polarized phase function are important optical parameters, which describe scattering properties of atmospheric aerosol particles. Polarization of skylight induced by the scattering processes is sensitive to the scattering properties of aerosols. The Stokes parameters <i>I, Q, U</i> and the polarized radiance <i>L<sub>p</sub></i> of skylight measured by the CIMEL dual-polar sun-sky radiometer CE318- DP can be use to retrieve the phase function and polarized phase function, respectively. Two different observation geometries (i.e., the principal plane and almucantar) are preformed by the CE318-DP to detect skylight polarization. Polarization of skylight depends on the illumination and observation geometries. For the same solar zenith angle, retrievals of the phase function and the polarized phase function are still affected by the observation geometry. The performance of the retrieval algorithm for the principal plane and almucantar observation geometries was assessed by the numerical experiments at two typical high and low sun’s positions (i.e. solar zenith angles are equal to 45&amp;deg; and 65&amp;deg;). Comparing the results for the principal plane and almucantar geometries, it is recommended to utilize the principal plane observations to retrieve the phase function when the solar zenith angle is small. The Stokes parameter <i>U</i> and the polarized radiance <i>L<sub>p</sub></i> from the almucantar observations are suggested to retrieve the polarized phase function, especially for short wavelength channels (e.g., 440 and 500&amp;thinsp;nm).

Polarization-Squeezed Light Formation in Cubic–Nonlinear Medium with Dissipation

1997 ◽  
Vol 06 (04) ◽  
pp. 455-466 ◽  
Author(s):  
A. S. Chirkin ◽  
V. V. Volokhovsky
Keyword(s):  
Radiation Intensity ◽  
Noise Level ◽  
Thermal Noise ◽  
Stokes Parameter ◽  
Stokes Parameters ◽  
Correlation Property ◽  
Third Order ◽  
Interaction Length ◽  
Mean Values ◽  
Squeezed Light

The influence of losses and thermal noise on the polarization-squeezed light formation in a medium with third order nonlinearity has been analysed. A method of analysis based on the delta-correlation property of noise was developed. Mean values and variances of some Stokes parameter of the light was calculated. It was shown that optimal interaction length for effective fluctuation suppression in the Stokes parameters is determined by damping constants, noise level, and radiation intensity.

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