المؤلفون: Pakzad, H. R.

المصدر: Journal of the Earth & Space Physics / Fīzīk-i Zamīn va Faz̤ā; Autumn2023, Vol. 49 Issue 3, p699-706, 8p

مصطلحات موضوعية: QUANTUM plasmas, MAGNETIC fields, PLASMA waves, GEOMAGNETISM, ACOUSTIC wave propagation, ION acoustic waves, MAGNETIC field effects, MAGNETIC flux density

مستخلص: The propagation of nonlinear waves such as ion acoustic, electron acoustic, dust acoustic in the plasma media have been studied in different equilibrium and non-equilibrium conditions. Meanwhile, the study of these waves in magnetized plasmas, due to the effect of the external magnetic field on the plasma with different angles of wave propagation has been less addressed. There are extensive studies on the propagation of acoustic waves in magnetized plasma, which show that when the intensity of the magnetic field is constant, these waves propagate as soliton waves with a stable profile in the plasma. In fact, the uniform magnetic field does not interfere with the fluctuations of the plasma particles to produce dilute and dense regions and wave propagation, and for this reason, the harmonic soliton wave is propagated in the plasma. We know factors such as heating, particles collision and viscosity that cause perturbation in plasma particles fluctuations. In this situation, the propagation of the acoustic wave will no longer be in the soliton form and a shock wave may appear. On the other hand, we know that in actual conditions, the magnetic field governing laboratory plasmas such as tokamaks and also astrophysical and space plasmas are not constant at all. As a realistic example, the Earth's magnetic field intensity varies from 30000 nT in 0 (latitude): +60 (altitude) to 45000 nT in 10 (latitude): +90 (altitude), where the magnetic field is almost horizontal. Therefore it would interesting to study the presence of a non-uniform magnetic field. For this purpose, we considered an ion-electron magnetized plasma model and numerically investigate the ion acoustic wave behavior in this medium, while the strength of the magnetic field is not the same in different parts of the plasma. In this situation, for simplicity in calculations, we assume the direction of the magnetic field to be constant. We use the second order Runge-Kutta method and by numerically solving the basic equations of the ion acoustic wave, it is shown that the stable behavior of the solitonic wave is perturbed in the presence of varying magnetic field and in this case, the wave propagates as a shock wave. Now we can introduce the non-uniform magnetic field along with factors such as viscosity, heating, collision etc. as the new sources of producing the acoustic shock waves in plasmas. We also studied the cases where the collisional terms and gyro frequencies of the particles are considered. In this condition, the effects of the nonuniform magnetic field are different. This subject can also be considered for other acoustic waves in different temperature and density models, various non-thermal plasmas and other features in astrophysical and laboratory plasmas. [ABSTRACT FROM AUTHOR]

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المؤلفون: Khalid Abdul-Kareem Hadi, Marwa D. Abdulkareem

المصدر: Baghdad Science Journal, Vol 17, Iss 3(Suppl.) (2020)

مصطلحات موضوعية: Ionospheric Parameters, Lowest Usable Frequency (LUF), Maximum Usable Frequency (MUF), Optimum Working Frequency (OWF), Radio Wave Propagation., Science

الوصف: In this work, the relationship between the ionospheric parameters (Maximum Usable Frequency (MUF), Lowest Usable Frequency (LUF) and Optimum working Frequency (OWF)) has been studied for the ionosphere layer over the Iraqi zone. The capital Baghdad (44.42oE, 33.32oN) has been selected to represent the transmitter station and many other cities that spread over Iraqi region have represented as receiver stations. The REC533 communication model considered as one of the modern radio broadcasting version of ITU has been used to calculate the LUF parameter, while the MUF and OWF ionospheric parameters have been generated using ASAPS international communication model which represents one of the most advanced and accurate HF sky wave propagation models. The study has been conducted for the annual and seasonal time periods of the years (2009 and 2014) of the solar cycle 24. The results of the seasonal and annual tests have indicated that the interrelationship between the MUF and OWF with LUF was a fourth order polynomial equation, while the reciprocal relationship between the MUF and OWF was a simple relationship that could be represented by a linear regression equation. The reciprocal relationships between MUF, LUF and OWF parameters (present values) have shown a good fitting with the data generated using the international models (predicted values) and theoretical values calculated from the criterion equation.

وصف الملف: electronic resource

العلاقة: http://bsj.uobaghdad.edu.iq/index.php/BSJ/article/view/4247Test; https://doaj.org/toc/2078-8665Test; https://doaj.org/toc/2411-7986Test

الوصول الحر: https://doaj.org/article/565a84d6af7c44f2b68950c835ad8cc0Test

المؤلفون: Alwand Tahir R. Dizayee

المصدر: Al-Qadisiyah Journal For Agriculture Sciences, Vol 9, Iss 2, Pp 193-197 (2019)
Al-Qadisiyah Journal For Agriculture Sciences, Vol 9, Iss 2 (2019)

مصطلحات موضوعية: chemistry.chemical_element, humic acid, lcsh:Plant culture, Interference (wave propagation), SB1-1110, lcsh:Agriculture, lcsh:Botany, Humic acid, lcsh:SB1-1110, Boron, chemistry.chemical_classification, biology, cauliflower, lcsh:S, Botany, Plant culture, Agriculture, General Medicine, biology.organism_classification, Water productivity, lcsh:QK1-989, Horticulture, chemistry, Yield (chemistry), QK1-989, Brassica oleracea, water productivity, boron foliar

الوصف: An experiment has been carried out at field in Gardmalla/Qushtapa with reading GPS (longitude 440035E, Latitude 360023N) ,414 meter above sea level, 15.5 Km far Southern of Erbil city during the Winter season of 2017 to test the effect of application humic acid in soil and spraying boron on the growth and productivity of water on cauliflower. Factorial experiment 3 (humic acid) (0, 10 and 20 kg ha-1 using) × 4 (boron foliar) ( 0, 0.5, 1.0, and 2.0 kg B ha-1 ) using solid snow cultivars in RCBD with three replicates.Planting solid snow cultivars was done on 11/7/2017 (seeding date), 10 /8 /2017 (transfer to field) and 22/12/ 2017 picking or harvesting date. Irrigation water was applied at 35% depletion to the depth of total plant root and calculate the depth of water applied up to field capacity. Irrigation system is surface flow irrigation through line pipe provided with meter gages for measuring water applied.The results show that the application of boron and humic acid increase significantly all growth and yield parameters of cauliflower improved the highest values of leaf length (cm), leaf width (cm) and chlorophyll content (mg/cm2), recorded 47.67 cm, 28.45 cm and 40.66 mg/cm2; 75.39 cm, 37.55 cm and 43.11 mg/cm2 and 80.0 cm, 40.29 cm and 47.33 mg/cm2 in treatment 2 kg ha-1 of boron foliar and 0, 10 and 20 kg ha-1 of humic acid addition, respectively. The values of curd weight (kg), curd diameter (cm) and total yield (Mg/ha) values were 0.97 kg, 19.45 cm and 25.38 Mg/ha; 1.33 kg, 22.33 cm and 32.66 Mg/ha and 1.40 kg, 23.78 cm and 36.53 Mg/ha in treatment 2 kg ha-1 of boron foliar and 0, 10 and 20 kg ha-1 of humic acid application, respectively. Values of water productivity (Kg/m3) ranged between 6.25 to 12.18 Kg fresh (green) curd m-3 water applied.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7b5f19414d6f617f31013e5f815043ceTest
https://jouagr.qu.edu.iq/article_167057_11caa81097d6abede30a0d7894a5281f.pdfTest

المؤلفون: Mashaan Attallah Mahmood, Akram Noori Muhammad

المصدر: Mustansiriyah Journal of Science, Vol 29, Iss 2, Pp 179-181 (2018)

مصطلحات موضوعية: Physics, business.industry, Laser source, Measure (physics), Physics::Optics, Laser source, image fringes, wavelength, Interference (wave propagation), Wavelength, Light source, Optics, He ne laser, lcsh:Q, business, lcsh:Science, Earth-Surface Processes

الوصف: A new optical method used in our lab to get clear fringes of interference use “He Ne laser” as a light source. These experiment construct firstly to avoid our need to sodium lamb, Secondly, a convex lens was used to obtain a large image fringes to make the parameters more accurate than using the real fringes, by using a new mathematical relationships, the wavelength was measured. The results were more accurate than the normal methods used.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b9360cff4eb9d14affbce8c6ffdac3cdTest
http://mjs.uomustansiriyah.edu.iq/ojs1/index.php/MJS/article/view/410Test

المؤلفون: Salah R. Al-Zaidee, Alfadhel Basil Kasim

المصدر: Engineering Journal, Vol 24, Iss 5 (2018)

مصطلحات موضوعية: geography, geography.geographical_feature_category, virtual wind tunnel, interference effect, CFD, CWE, business.industry, Elevation, Structural engineering, Design load, Computational fluid dynamics, Urban area, Interference (wave propagation), Wind engineering, Software, lcsh:TA1-2040, Environmental science, business, lcsh:Engineering (General). Civil engineering (General), Wind tunnel

الوصف: The constructed building in the urban area is subject to wind characteristics due to the influence of surrounding buildings. The residential complexes currently being built in Iraq represent a case study for the subject of this research. Therefore, the objective of this study is to identify the interference effect because of adjacent buildings effects on the mid-rise building. The speed and pressure of the wind have been numerically simulated as well as wind load has been simulated by using a virtual wind tunnel which is available in Autodesk Robot Structural Analysis, RSA, software. Two identical adjacent buildings have been simulated and many coefficients were included in this study such as the spacing, directionality, and elevation of adjacent building coefficients. The results of the study showed that the neighboring building could increase or decrease the wind pressure significantly so that it cannot be neglected.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fe99e5edd30798254b025f0a9c49bc5fTest
http://joe.uobaghdad.edu.iq/index.php/main/article/view/587Test

المؤلفون: Bascom, Willard

مصطلحات موضوعية: Underwater archaeology, Archaeological objects, Sound wave propagation, Deep sea diving

الوصف: Published in 12 languages

وصف الملف: Electronic; Paper; online resource

العلاقة: The UNESCO Courier: a window open on the world, XXV, 5; https://unesdoc.unesco.org/ark:/48223/pf0000078276Test; https://unesdoc.unesco.org/ark:/48223/pf0000052093Test

الإتاحة: https://unesdoc.unesco.org/ark:/48223/pf0000052093Test

المؤلفون: Jenny, Hans

مصطلحات موضوعية: Acoustics, Sound wave propagation, Sound recordings, Image formation, Creativity, Music, Avant-garde art

الوصف: Published in 13 editions

وصف الملف: Electronic; Paper; online resource

العلاقة: The UNESCO Courier: a window open on the world, XXII, 12; https://unesdoc.unesco.org/ark:/48223/pf0000078290Test; https://unesdoc.unesco.org/ark:/48223/pf0000058744Test

الإتاحة: https://unesdoc.unesco.org/ark:/48223/pf0000058744Test

مصطلحات موضوعية: Noise pollution, Human environment, Noise control, Sound wave propagation

الوصف: Published in 9 editions

وصف الملف: Electronic; Paper; online resource

العلاقة: The UNESCO Courier: a window open on the world, XX, 7; https://unesdoc.unesco.org/ark:/48223/pf0000078367Test; https://unesdoc.unesco.org/ark:/48223/pf0000012619Test

الإتاحة: https://unesdoc.unesco.org/ark:/48223/pf0000012619Test

المؤلفون: Beranek, Leo L.

مصطلحات موضوعية: Noise control, Aircraft, Air traffic, Road transport, Urban environment, Sound wave propagation, Airports

الوصف: Published in 9 editions

وصف الملف: Electronic; Paper; online resource

العلاقة: The UNESCO Courier: a window open on the world, XX, 7; https://unesdoc.unesco.org/ark:/48223/pf0000078367Test; https://unesdoc.unesco.org/ark:/48223/pf0000009901Test

الإتاحة: https://unesdoc.unesco.org/ark:/48223/pf0000009901Test