Artykuły w czasopismach: „Radiations generation”

1

Hussain, Saba, Ram Kishor Singh i R. P. Sharma. "Strong terahertz field generation by relativistic self-focusing of hollow Gaussian laser beam in magnetoplasma". Laser and Particle Beams 34, nr 1 (9.12.2015): 86–93. http://dx.doi.org/10.1017/s0263034615000981.

Pełny tekst źródła

Streszczenie:

AbstractThe present paper proposes a model for the generation of Terahertz (THz) radiation by self-focused hollow Gaussian beam (HGB) in collisionless magnetized rippled density plasma. At high intensities, the change in the electron mass occurs due to relativistic effect, introducing a nonlinearity in the plasma leading to the self-focusing of the HGB. The nonlinear interaction of this highly intense self-focused HGB with the electron plasma wave in the rippled density plasma, satisfying proper phase matching conditions, results in the resonant excitation of THz radiations at the beat frequency. We have studied the dependence of generated THz radiations on the order of the HGB as well as on the static background magnetic field. The results show that the intensity of the generated radiations is highly sensitive to both of these parameters. For the current scheme the power of the generated THz waves comes out to be of the order of Gigawatts.

Style APA, Harvard, Vancouver, ISO itp.

2

Hu, Qing. "Generation of Terahertz Emission Based on Intersubband Transitions". International Journal of High Speed Electronics and Systems 12, nr 04 (grudzień 2002): 995–1024. http://dx.doi.org/10.1142/s0129156402001897.

Pełny tekst źródła

Streszczenie:

In this chapter, we present our work on the development of coherent THz sources based on intersubband transition in quantum-well structures. The main focus is on electrically pumped or quantum-cascade structures, which have been quite successful in generating coherent radiation at mid-infrared frequencies. Relevant issues, such as various depopulation intersubband scattering rates, the role of complex phonon spectra, and coherent vs. incoherent tunneling are discussed in details. Optically pumped sources, including optical parametric amplifiers, and both intersubband and interband pumped THz emitters, are also investigated for their feasibility in generating coherent THz radiations.

Style APA, Harvard, Vancouver, ISO itp.

3

Bakhtiari, Farhad, Shole Golmohammady, Masoud Yousefi, Fatemeh D. Kashani i Bijan Ghafary. "Generation of terahertz radiation in collisional plasma by beating of two dark hollow laser beams". Laser and Particle Beams 33, nr 3 (10.06.2015): 463–72. http://dx.doi.org/10.1017/s026303461500049x.

Pełny tekst źródła

Streszczenie:

AbstractThis paper presents a scheme of terahertz radiation generation based on beating of two dark hollow laser beams with different frequencies, the same electric field amplitudes, in actual plasma with spatially periodic density that electron–neutral collisions have taken into account. The main feature of considered hollow laser beams is, having the same power at different beam orders. Because of special distribution in beam intensity gradient in dark hollow laser beam, the produced terahertz radiation has special field profile. The effects of laser and plasma parameters on terahertz radiation generation are investigated analytically. It can be deduced that by increasing beating frequency, efficiency of terahertz generation decreases which can be compensated by manipulating density ripple magnitudes and dark-size adjusting parameter. The intensity of the emitted radiations is found to be highly sensitive to the beam order. Based on the results of this paper, optimization of laser and plasma parameters can increase the efficiency of terahertz radiation generation strongly.

Style APA, Harvard, Vancouver, ISO itp.

4

Tian, Lin, Lin Chen, Peng Zhang, Bo Hu, Yang Gao i Yidan Si. "The Ground-Level Particulate Matter Concentration Estimation Based on the New Generation of FengYun Geostationary Meteorological Satellite". Remote Sensing 15, nr 5 (5.03.2023): 1459. http://dx.doi.org/10.3390/rs15051459.

Pełny tekst źródła

Streszczenie:

The new-generation FengYun geostationary meteorological satellite has a high spatial and temporal resolution, which is advantageous in environmental assessments and air pollution monitoring. This study researched the ground-level particulate matter concentration estimation, based on satellite-observed radiations. The radiation of ground-level particulate matter is separate from the apparent radiation observed by satellites. The positive correlation between PM2.5 and PM10 is also considered to improve the accuracy of inversion results and the interpretability of the estimation model. Then, PM2.5 and PM10 concentrations were estimated synchronously every 5 min in mainland China based on FY-4A satellite directly observed radiations. The validation results showed that the improved model estimated results were close to the ground site measured results, with a high determination coefficient (R2) (0.89 for PM2.5, and 0.90 for PM10), and a small Root Mean Squared Error (RMSE) (4.69 μg/m3 for PM2.5 concentrations, and 13.77 μg/m3 for PM10 concentrations). The estimation model presented a good performance in PM2.5 and PM10 concentrations during typical haze and dust storm cases, indicating that it is applicable in different weather conditions and regions.

Style APA, Harvard, Vancouver, ISO itp.

5

Rehman, Khalil Ur, Wasfi Shatanawi i Andaç Batur Çolak. "Levenberg–Marquardt Training Technique Analysis of Thermally Radiative and Chemically Reactive Stagnation Point Flow of Non-Newtonian Fluid with Temperature Dependent Thermal Conductivity". Mathematics 11, nr 3 (2.02.2023): 753. http://dx.doi.org/10.3390/math11030753.

Pełny tekst źródła

Streszczenie:

We have examined the magnetized stagnation point flow of non-Newtonian fluid towards an inclined cylindrical surface. The mixed convection, thermal radiation, viscous dissipation, heat generation, first-order chemical reaction, and temperature-dependent thermal conductivity are the physical effects being carried for better novelty. Mathematical equations are constructed for four different flow regimes. The shooting method is used to evaluate the heat transfer coefficient at the cylindrical surface with and without heat generation/thermal radiation effects. For better examination, we have constructed artificial neural networking models with the aid of the Levenberg–Marquardt training technique and Purelin and Tan-Sig transfer functions. The Nusselt number strength is greater for fluctuations in the Casson fluid parameter, Prandtl number, heat generation, curvature, and Eckert number when thermal radiations are present.

Style APA, Harvard, Vancouver, ISO itp.

6

Guo, L., H. W. Zhang i H. C. Wu. "High-frequency radio-wave emission by coherent transition radiation of runaway electrons produced by lightning stepped leaders". Physics of Plasmas 29, nr 9 (wrzesień 2022): 093102. http://dx.doi.org/10.1063/5.0102132.

Pełny tekst źródła

Streszczenie:

Lightning can produce multiband radio waves and high-energy radiations. Some of them are associated with the formation of lightning leaders. However, their generation mechanisms are not fully understood yet. Based on the understanding of thermal runaway electrons generated at the leader tip, we propose transition radiation of these runaway electrons as an alternative mechanism for producing very-high-frequency radio signals. Transition radiations are induced when runaway electrons cross the interfaces between lightning coronas and the air. By the use of estimated parameters of electron beams emerging from the leader tips, we calculate their coherent transition radiation and find that the energy spectra and radiation powers are consistent with some detection results from stepped leaders and even narrow bipolar events. Moreover, our model also predicts strong THz radiation during the stepped-leader formation. As a standard diagnosis technique of electron bunches, the proposed coherent transition radiation here may be able to reconstruct the actual properties of electron beams in the leader tips, which remains an open question.

Style APA, Harvard, Vancouver, ISO itp.

7

Bakhtiari, Farhad, Masoud Yousefi, Shole Golmohammady, Seyed Masoud Jazayeri i Bijan Ghafary. "Generation of terahertz radiation by beating of two circular flat-topped laser beams in collisional plasma". Laser and Particle Beams 33, nr 4 (15.10.2015): 713–22. http://dx.doi.org/10.1017/s026303461500083x.

Pełny tekst źródła

Streszczenie:

AbstractThis paper presents a scheme of terahertz (THz) radiation generation based on beating of two flat-topped laser beams by different frequencies and the same electric field amplitudes in actual plasma with spatially periodic density that electron–neutral collisions have been taken into account. Flat-topped laser beams have the exclusive features such as steep gradient in distribution of laser intensities, wider cross-section in comparison with other profiles, which make stronger ponderomotive force and lead to stronger nonlinear current and hence, THz radiation of higher field. The effects of laser and plasma parameters on THz radiation generation are investigated analytically. It is shown that by increasing the order of flatness of incident laser beams, because of their steep gradient, good enhancement in emitted THz radiation take place. It can be deduced that by increasing beating frequency, efficiency of THz generation decreases which can be compensated by manipulating in density ripple magnitudes. The intensity of the emitted radiations is found to be highly sensitive to the order of flatness. Based on the results of this paper, optimization of laser and plasma parameters can increase the efficiency of THz radiation generation strongly.

Style APA, Harvard, Vancouver, ISO itp.

8

Gunel, Imanova, Bekpulatov Ilkhom, Aliyev Anar i Barkaoui Sami. "Importance of the radiations in water splitting for hydrogen generation". Annals of Advances in Chemistry 7, nr 1 (14.03.2023): 031–36. http://dx.doi.org/10.29328/journal.aac.1001040.

Pełny tekst źródła

Streszczenie:

The review article examines the production of molecular hydrogen from the decomposition of water by various irradiation methods. The article shows different types of radiation: UV radiation, visible radiation, gamma radiation, X-ray radiation and neutron radiation. Electrons generated by radiation inside a nanoparticle of radius R suspense in fluid water are diffused with equal probability in all directions inside the particle and gradually lose their kinetic energy as a result of elastic and inelastic collisions. Some of these electrons are transported to the nanoparticle surface during the physical and physicochemical stages of the process and emitted into the water. It is extremely important for the formation of nanostructured materials after exposure to ordered nanostructure from the new phase with a period of a few nanometers, promoting the preservation of the properties of materials under high irradiation.

Style APA, Harvard, Vancouver, ISO itp.

9

Ali, Suha Ismail Ahmed, i Éva Lublóy. "Radiation shielding structures : Concepts, behaviour and the role of the heavy weight concrete as a shielding material - Rewiev". Concrete Structures 21 (2020): 24–30. http://dx.doi.org/10.32970/cs.2020.1.4.

Pełny tekst źródła

Streszczenie:

The construction of radiation shielding buildings still developed. Application of ionizing radiations became necessary for different reasons, like electricity generation, industry, medical (therapy treatment), agriculture, and scientific research. Different countries all over the world moving toward energy saving, besides growing the demand for using radiation in several aspects. Nuclear power plants, healthcare buildings, industrial buildings, and aerospace are the main neutrons and gamma shielding buildings. Special design and building materials are required to enhance safety and reduce the risk of radiation emission. Radiation shielding, strength, fire resistance, and durability are the most important properties, cost-effective and environmentally friendly are coming next. Heavy-weight concrete (HWC) is used widely in neutron shielding materials due to its cost-effectiveness and worthy physical and mechanical properties. This paper aims to give an overview of nuclear buildings, their application, and behaviour under different radiations. Also to review the heavy-weight concrete and heavy aggregate and their important role in developing the neutrons shielding materials. Conclusions showed there are still some gaps in improving the heavy-weight concrete (HWC) properties.

Style APA, Harvard, Vancouver, ISO itp.

10

Singhal, Umang, i Yash Pal. "Propellant-Less Thrust Generation - A Review". Applied Mechanics and Materials 852 (wrzesień 2016): 639–45. http://dx.doi.org/10.4028/www.scientific.net/amm.852.639.

Pełny tekst źródła

Streszczenie:

This paper introduces a concept of propellant-less microwave thruster for upper stage and space applications. The propellant-less microwave thruster works on classical electromagnetic theory, where the microwave radiations are converted to the electromagnetic pressure that acts as axial thrust. In microwave thrusters, microwaves are radiated to a sealed conical cavity which follows the contour of the thrusters to produce pressure. Normally, there are three types of methods by which thrust can be produced without utilizing any propellant. Cannae Drive, EmDrive, and the Wrap Drive are mostly used. The first two are based on the principle of microwave radiation, whereas the third method is just a concept in various science fiction films. The EmDrive can produce a small amount of thrust, therefore, its application is limited to upper stage thruster, orbit/trajectory correction, and deep-space exploration. This paper provides an insight on the feasibility of EmDrive for space application by comparing its performance with ion propulsion system. The proposed microwave propulsion system has low system mass (typically in Kgs), produces high thrust (in mN) and even has higher specific impulse (in years) which can outweigh the current ion propulsion system.

Style APA, Harvard, Vancouver, ISO itp.

11

Žofková, Alena, Heather Mark i Naveen Weerasekera. "Solid State Heat Pipe Based Waste Heat Recovery System for Domestic Power Generation at Local Energy Emergencies". European Journal of Energy Research 2, nr 3 (27.06.2022): 23–27. http://dx.doi.org/10.24018/ejenergy.2022.2.3.66.

Pełny tekst źródła

Streszczenie:

Through this work, we have studied a thermoelectric generator-based waste heat recovery system with a low response time for fast energy generation under low and high direct normal solar radiations. Under direct normal radiation of 1000 W m-2, a TEG voltage up to~3 V has been observed within a saturation time of~900 s. A large temperature gradient (15000 K/m) is produced between hot and cold ends of the TEG module under a simple application of solid-fluid convective heat exchanger. Our results show the potential of remote heating and heat transfer for TEG power generation for small scale power emergencies.

Style APA, Harvard, Vancouver, ISO itp.

12

Berdah, M., J. P. Visticot, C. Dedonder-Lardeux, D. Solgadi i B. Soep. "Generation of picosecond VUV radiation by four-wave mixing of nanosecond and picosecond laser radiations". Optics Communications 124, nr 1-2 (luty 1996): 118–20. http://dx.doi.org/10.1016/0030-4018(95)00628-1.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

13

Ali, Imran, Gunel T. Imanova, X. Y. Mbianda i Omar M. L. Alharbi. "Role of the radiations in water splitting for hydrogen generation". Sustainable Energy Technologies and Assessments 51 (czerwiec 2022): 101926. http://dx.doi.org/10.1016/j.seta.2021.101926.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Guschanski, Katerina, Johannes Krause, Susanna Sawyer, Luis M. Valente, Sebastian Bailey, Knut Finstermeier, Richard Sabin i in. "Next-Generation Museomics Disentangles One of the Largest Primate Radiations". Systematic Biology 62, nr 4 (17.04.2013): 539–54. http://dx.doi.org/10.1093/sysbio/syt018.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

15

DABAGOV, S. B., M. FERRARIO, L. PALUMBO i L. SERAFINI. "CHANNELING PROJECTS AT LNF: FROM CRYSTAL UNDULATORS TO CAPILLARY WAVEGUIDES". International Journal of Modern Physics A 22, nr 23 (20.09.2007): 4280–309. http://dx.doi.org/10.1142/s0217751x07037834.

Pełny tekst źródła

Streszczenie:

Frascati's National Laboratories (LNF INFN) are well known in the world for pioneering research in the particle interaction and synchrotron radiation physics fields. Good experience in designing accelerators, storage rings and beamlines for synchrotron radiation allows presently LNF to be in the frontier for the construction of new X-ray generation sources. This report is an introduction to new research activity "Coherent Scattering Phenomena for Radiations in Solids" started in Frascati within the approved projects SPARC, SPARX and PLASMON-X. The main purpose of the project is to develop research area for studying the channeling phenomena of charged and neutral particles in periodic solid structures.

Style APA, Harvard, Vancouver, ISO itp.

16

Jing, Liqiao, Zuojia Wang, Xiao Lin, Bin Zheng, Su Xu, Lian Shen, Yihao Yang, Fei Gao, Min Chen i Hongsheng Chen. "Spiral Field Generation in Smith-Purcell Radiation by Helical Metagratings". Research 2019 (27.02.2019): 1–8. http://dx.doi.org/10.34133/2019/3806132.

Pełny tekst źródła

Streszczenie:

Moving electrons interacting with media can give rise to electromagnetic radiations and has been emerged as a promising platform for particle detection, spectroscopies, and free-electron lasers. In this letter, we investigate the Smith-Purcell radiation from helical metagratings, chiral structures similar to deoxyribonucleic acid (DNA), in order to understand the interplay between electrons, photons, and object chirality. Spiral field patterns can be generated while introducing a gradient azimuthal phase distribution to the induced electric dipole array at the cylindrical interface. Experimental measurements show efficient control over angular momentum of the radiated field at microwave regime, utilizing a phased electromagnetic dipole array to mimic moving charged particles. The angular momentum of the radiated wave is determined solely by the handedness of the helical structure, and it thus serves as a potential candidate for the detection of chiral objects. Our findings not only pave a way for design of orbital angular momentum free-electron lasers but also provide a platform to study the interplay between swift electrons with chiral objects.

Style APA, Harvard, Vancouver, ISO itp.

17

Jing, Liqiao, Zuojia Wang, Xiao Lin, Bin Zheng, Su Xu, Lian Shen, Yihao Yang, Fei Gao, Min Chen i Hongsheng Chen. "Spiral Field Generation in Smith-Purcell Radiation by Helical Metagratings". Research 2019 (27.02.2019): 1–8. http://dx.doi.org/10.1155/2019/3806132.

Pełny tekst źródła

Streszczenie:

Moving electrons interacting with media can give rise to electromagnetic radiations and has been emerged as a promising platform for particle detection, spectroscopies, and free-electron lasers. In this letter, we investigate the Smith-Purcell radiation from helical metagratings, chiral structures similar to deoxyribonucleic acid (DNA), in order to understand the interplay between electrons, photons, and object chirality. Spiral field patterns can be generated while introducing a gradient azimuthal phase distribution to the induced electric dipole array at the cylindrical interface. Experimental measurements show efficient control over angular momentum of the radiated field at microwave regime, utilizing a phased electromagnetic dipole array to mimic moving charged particles. The angular momentum of the radiated wave is determined solely by the handedness of the helical structure, and it thus serves as a potential candidate for the detection of chiral objects. Our findings not only pave a way for design of orbital angular momentum free-electron lasers but also provide a platform to study the interplay between swift electrons with chiral objects.

Style APA, Harvard, Vancouver, ISO itp.

18

Marinchio, H., G. Sabatini, C. Palermo, P. Nouvel, J. Torres, L. Varani, P. Shiktorov, E. Starikov i V. Gružinskis. "Plasma Oscillations in Nanotransistors: Application to THz Radiations Detection and Generation". Acta Physica Polonica A 119, nr 2 (luty 2011): 103–6. http://dx.doi.org/10.12693/aphyspola.119.103.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

19

Hematizadeh, A., F. Bakhtiari, S. M. Jazayeri i B. Ghafary. "Strong terahertz radiation generation by beating of two laser beams in magnetized overdense plasma". Laser and Particle Beams 34, nr 3 (22.07.2016): 527–32. http://dx.doi.org/10.1017/s0263034616000410.

Pełny tekst źródła

Streszczenie:

AbstractTerahertz (THz) radiation generation by nonlinear mixing of two laser beams, obliquely incident on an overdense plasma is investigated. In an overdense plasma, the laser beams penetrate to only thin layer of a plasma surface and reflected. At this thin layer, the laser beams exert a ponderomotive force on the electrons of plasma and impart them oscillatory velocity at the different frequency of lasers. THz waves appear in the reflected component from the plasma surface. The amplitude of THz waves can be augmented by applying the magnetic field perpendicular to the direction of propagation of lasers. It is found that the field strength of the emitted THz radiations is sensitive to the angle of incident of the laser beams, beat frequency, and magnetic field strength. In this scheme, the magnetic field strength plays an important role for strong THz wave generation.

Style APA, Harvard, Vancouver, ISO itp.

20

Bratman, Vladimir, Yuri Lurie, Yuliya Oparina i Andrey Savilov. "Capabilities of Terahertz Cyclotron and Undulator Radiation from Short Ultrarelativistic Electron Bunches". Instruments 3, nr 4 (11.10.2019): 55. http://dx.doi.org/10.3390/instruments3040055.

Pełny tekst źródła

Streszczenie:

Mechanisms of coherent spontaneous cyclotron and undulator radiations of short dense bunches, in which electrons move along the same stationary helical trajectories, but have different dynamic properties, have been compared in detail. The results are based on the simplest 1D model in the form of a plane consisting of uniformly distributed synchronously moving and in-phase emitting particles, as well as numerical 3D codes developed to study the dynamics of bunches in waveguides taking into account the effects of the radiation and spatial charge fields. For cyclotron radiation under group synchronism conditions, the Coulomb expansion of a bunch occurs along the surface of a constant wave phase with the formation of an effectively radiating coherent structure. A significantly higher radiation frequency, but with a lower efficiency, can be obtained in the regime of simultaneous excitation of high-frequency (autoresonant) and low-frequency waves; in the field of the latter, stabilization of the bunch phase size can be achieved. Such a two-wave generation is much more efficient when the bunches radiate in the combined undulator and strong guiding magnetic fields under conditions of the negative mass instability, when both the Coulomb interaction of the particles and the radiation field stabilize the longitudinal size of the bunch.

Style APA, Harvard, Vancouver, ISO itp.

21

Malik, Hitendra K., i Sheetal Punia. "Investigating pair-production by Breit–Wheeler process in a collisional plasma". Laser Physics Letters 19, nr 11 (7.10.2022): 116003. http://dx.doi.org/10.1088/1612-202x/ac92de.

Pełny tekst źródła

Streszczenie:

Abstract Positrons have many potential applications in the field of high-energy nuclear and particle physics. For the generation of such high-energy positrons, we propose a mechanism via an interaction of optical vortex laser beams with collisional plasma. Based on the multiphoton Breit–Wheeler mechanism, the production of electron–positron pairs shows to be strongly dependent on the energy associated with the synchrotron radiation. Such radiations are emitted by accelerated charged particles in the plasma channel under quasistatic spontaneous magnetic field that confines the motion of the electrons. For the precise regulation of the accelerated positrons important quantities such as the probabilistic generation of positrons and the angular momentum of the plasma electrons are evaluated and discussed. It is observed that the use of the incident Laguerre–Gaussian laser beam helps to generate on-axis sheath formation to focus and accelerate the produced positrons.

Style APA, Harvard, Vancouver, ISO itp.

22

SAKABE, Shuji, Toshiyuki IIDA i Akito TAKAHASHI. "Generation of Radiations with Ultra-intense Lasers. Expectation on "Laser Nuclear Engineering"." Journal of the Atomic Energy Society of Japan / Atomic Energy Society of Japan 43, nr 10 (2001): 996–1004. http://dx.doi.org/10.3327/jaesj.43.996.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

23

Gemini, L., D. Margarone, S. Trusso, L. Juha, J. Limpouch, T. Mocek i P. M. Ossi. "Generation of periodic structures on SiC upon laser plasma XUV/NIR radiations". Laser and Particle Beams 31, nr 3 (6.08.2013): 547–50. http://dx.doi.org/10.1017/s026303461300058x.

Pełny tekst źródła

Streszczenie:

AbstractSurface periodic structures are generated upon irradiation of a silicon carbide (SiC) thin film by the plasma produced by 40 fs pulses from a Ti:Sapphire laser focused onto a thick low density polyethylene (LDPE) foil facing the SiC film. Independently of the number of laser pulses applied, these structures, with average regular periodicity of 710 nm, are evident throughout all irradiated areas. We attribute their formation to the efficient coupling of the unfocused femtosecond laser pulse with the incoherent extreme ultraviolet component of the laser-generated LDPE plasma.

Style APA, Harvard, Vancouver, ISO itp.

24

Hasan, Bismah, i Kamran Raza. "Dual Band Slotted Printed Circular Patch Antenna With Superstrate and EBG Structure for 5G Applications". January 2019 38, nr 1 (1.01.2019): 227–38. http://dx.doi.org/10.22581/muet1982.1901.19.

Pełny tekst źródła

Streszczenie:

Slotted circular printed layered patch antenna is designed, simulated and fabricated for 5G (Fifth Generation) wireless communication applications. The antenna consists of slots in the main radiating circular patch element for miniaturizing the size of the radiating element and providing dual band radiation characteristics. The feed line is separated on bottom substrate layer with EBG (Electromagnetic Band-Gap) embedded for enhancing the gain characteristics of the antenna. Superstrate layer is also used for improving the gain of the antenna where the distance from the radiating antenna element is optimized for maximizing the impedance bandwidth and radiation characteristics. The feed realization and impedance matching of the radiating slotted circular patch antenna is done by inducing slot at the middle ground plane of the slot embedded circular patch antenna system. The proposed configuration provides power radiation gain values of more than 5 dB for the Ka band of communications, whereas the impedance bandwidth of the antenna is verified for the dual resonances at 27.5 and 28.5 GHz. Dual band radiation characteristics are attained by embedding and optimizing the slot length and width in the circular patch radiator element that is placed on the upper face of the substrate RT Rogers Duroid 5880 layer. The length of the microstrip feed line embedded in the lower layer of the substrate is optimized for providing required bandwidth characteristics for the dual frequency point radiations. The antenna configuration is designed, modeled and simulated in CST (Central Standard Time) Microwave studio. The antenna is fabricated and measured vs simulated frequency response, gain patterns and current density plots are presented for the verification of antenna operation in the desired frequency bands.

Style APA, Harvard, Vancouver, ISO itp.

25

Yatabe, Akihiro, i Shoichi Yamada. "Systematic analysis about the polarization in thermal radiations of magnetars". Proceedings of the International Astronomical Union 13, S337 (wrzesień 2017): 430–31. http://dx.doi.org/10.1017/s1743921317009024.

Pełny tekst źródła

Streszczenie:

AbstractWe calculated the polarization in soft X-ray emitted from magnetars, which are expected to be observed by the next-generation X-ray satellites. We consider possible conversions of photon’s polarization modes in the atmosphere and it cannot be ignored when the magnetic field is relatively weak B ≲ 1013G.

Style APA, Harvard, Vancouver, ISO itp.

26

Rehman, Khalil Ur, Andaç Batur Çolak i Wasfi Shatanawi. "Artificial Neural Networking (ANN) Model for Convective Heat Transfer in Thermally Magnetized Multiple Flow Regimes with Temperature Stratification Effects". Mathematics 10, nr 14 (7.07.2022): 2394. http://dx.doi.org/10.3390/math10142394.

Pełny tekst źródła

Streszczenie:

The convective heat transfer in non-Newtonian fluid flow in the presence of temperature stratification, heat generation, and heat absorption effects is debated by using artificial neural networking. The heat transfer rate is examined for the four different thermal flow regimes namely (I) thermal flow field towards a flat surface along with thermal radiations, (II) thermal flow field towards a flat surface without thermal radiations, (III) thermal flow field over a cylindrical surface with thermal radiations, and (IV) thermal flow field over a cylindrical surface without thermal radiations. For each regime, a Nusselt number is carried out to construct an artificial neural networking model. The model prediction performance is reported by using varied neuron numbers and input parameters, and the results are assessed. The ANN model is designed by using the Bayesian regularization training procedure, and a high-performing MLP network model is used. The data used in the creation of the MLP network was 80 percent for model training and 20 percent for testing. The graph shows the degree of agreement between the ANN model projected values and the goal values. We discovered that an artificial neural network model can provide high-efficiency forecasts for heat transfer rates having engineering standpoints. For both flat and cylindrical surfaces, the heat transfer normal to the surface reflects inciting nature towards the Prandtl number and heat absorption parameter, while the opposite is the case for the temperature stratification parameter and heat generation parameter. It is important to note that the magnitude of heat transfer is significantly larger for Flow Regime-IV in comparison with Flow Regimes-I, -II, and -III.

Style APA, Harvard, Vancouver, ISO itp.

27

Rehman, Khalil Ur, Wasfi Shatanawi i Andaç Batur Çolak. "Artificial Neural Networking Magnification for Heat Transfer Coefficient in Convective Non-Newtonian Fluid with Thermal Radiations and Heat Generation Effects". Mathematics 11, nr 2 (9.01.2023): 342. http://dx.doi.org/10.3390/math11020342.

Pełny tekst źródła

Streszczenie:

In this study, the Casson fluid flow through an inclined, stretching cylindrical surface is considered. The flow field is manifested with pertinent physical effects, namely heat generation, viscous dissipation, thermal radiations, stagnation point flow, variable thermal conductivity, a magnetic field, and mixed convection. In addition, the flow field is formulated mathematically. The shooting scheme is used to obtain the numerical data of the heat transfer coefficient at the cylindrical surface. Further, for comparative analysis, three different thermal flow regimes are considered. In order to obtain a better estimation of the heat transfer coefficient, three corresponding artificial neural networks (ANN) models were constructed by utilizing Tan-Sig and Purelin transfer functions. It was observed that the heat transfer rate exhibits an inciting nature for the Eckert and Prandtl numbers, curvature, and heat generation parameters, while the Casson fluid parameter, temperature-dependent thermal conductivity, and radiation parameter behave oppositely. The present ANN estimation will be helpful for studies related to thermal energy storage that have Nusselt number involvements.

Style APA, Harvard, Vancouver, ISO itp.

28

MUHAMMAD, Muhammad Liman, Ahmed Olamide FALUSI, Matthew Omoniyi ADEBOLA, Onyedi David OYEDUM, Aishatu Adamu GADO i Mohammed Chata DANG. "Spectrum and Frequency of Mutations Induced by Gamma Radiations in Three Varieties of Nigerian Sesame (Sesamum indicum L.)". Notulae Scientia Biologicae 10, nr 1 (27.03.2018): 87–91. http://dx.doi.org/10.15835/nsb10110219.

Pełny tekst źródła

Streszczenie:

Insufficient genetic variability is one of the major problems of plant breeding programmes, especially in sesame. Gamma radiation has been reported to be very effective in creating genetic variability in plants. Three varieties of Nigerian sesame were assessed for spectrum and frequency of mutation induced by Gamma radiations in M1 and M2 generations. The varieties (NCRIBEN-04E, NCRIBEN-01M and NCRIBEN-03L) were treated with four different doses of gamma rays (250, 350, 450 and 550 Gy). The treated and untreated seeds (control) were sown in planting bags (under field condition) to raise M1 plants. Four treatments: V1D5, V2D3, V3D2 and V3D4 (from M1 plants) were selected and bulked to obtain M2 populations. The results of M1 revealed four mutant fruit traits: multicarpellate capsule, multiple capsule per leaf axil, indehiscent capsule and terminal capsules. The highest frequencies of the traits in M1 generation were 2.50×10-2, 9.17×10-2, 1.67×10-2and3.33×10-2 respectively. The highest branching (7) was from NCRIBEN-01M, while the least (2) was from NCRIBEN-04E. The M2 plants were grouped into eight M2 lines. The dose range (250-550 Gy) was proved to be effective in inducing viable mutations in sesame.

Style APA, Harvard, Vancouver, ISO itp.

29

Smith, J. T., N. J. Willey i J. T. Hancock. "Low dose ionizing radiation produces too few reactive oxygen species to directly affect antioxidant concentrations in cells". Biology Letters 8, nr 4 (11.04.2012): 594–97. http://dx.doi.org/10.1098/rsbl.2012.0150.

Pełny tekst źródła

Streszczenie:

It has been hypothesized that radiation-induced oxidative stress is the mechanism for a wide range of negative impacts on biota living in radioactively contaminated areas around Chernobyl. The present study tests this hypothesis mechanistically, for the first time, by modelling the impacts of radiolysis products within the cell resulting from radiations (low linear energy transfer β and γ), and dose rates appropriate to current contamination types and densities in the Chernobyl exclusion zone and at Fukushima. At 417 µGy h −1 (illustrative of the most contaminated areas at Chernobyl), generation of radiolysis products did not significantly impact cellular concentrations of reactive oxygen species, or cellular redox potential. This study does not support the hypothesis that direct oxidizing stress is a mechanism for damage to organisms exposed to chronic radiation at dose rates typical of contaminated environments.

Style APA, Harvard, Vancouver, ISO itp.

30

Herder, Fabian, Arne W. Nolte, Jobst Pfaender, Julia Schwarzer, Renny K. Hadiaty i Ulrich K. Schliewen. "Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi". Proceedings of the Royal Society B: Biological Sciences 273, nr 1598 (22.06.2006): 2209–17. http://dx.doi.org/10.1098/rspb.2006.3558.

Pełny tekst źródła

Streszczenie:

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.

Style APA, Harvard, Vancouver, ISO itp.

31

MIZUUCHI, Kiminori, i Kazuhisa YAMAMOTO. "Blue and Ultra-Violet Radiations Using Quasi-Phase-Matched Second Harmonic Generation Devices". Review of Laser Engineering 32, nr 3 (2004): 160–64. http://dx.doi.org/10.2184/lsj.32.160.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

32

Matveev, Yu V. "Plasma dynamics and generation of hard radiations in experiments with cylindrical Z-pinches". Plasma Physics Reports 36, nr 3 (marzec 2010): 200–215. http://dx.doi.org/10.1134/s1063780x10030025.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

33

Liu, Shande, Junjie Zhang, Zeliang Gao, Lei Wei, Shaojun Zhang, Jingliang He i Xutang Tao. "Generation of 1.3μm and 1.5μm high-energy Raman radiations in α-BaTeMo2O9 crystals". Optical Materials 36, nr 4 (luty 2014): 760–63. http://dx.doi.org/10.1016/j.optmat.2013.11.021.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

34

R. Alnaab, Ismaeil, Harwan M. Taha, Zainab A. Abdulwahab i Mohammed Salah Al-Radhi. "Performance comparison between fixed tilt angle and solar tracking systems at Basra governorate: A case study". Indonesian Journal of Electrical Engineering and Computer Science 26, nr 1 (1.04.2022): 184. http://dx.doi.org/10.11591/ijeecs.v26.i1.pp184-193.

Pełny tekst źródła

Streszczenie:

Theoretical <span lang="EN-US">calculations and online system simulations using PVWatts and global solar atlas simulators, were conducted in this study to find the difference in solar power production between fixed solar power systems and tracking systems at Basra Governorate. The research included the analysis of geographical location and weather conditions and their effect on output power. The reliant power resource types and power generation of the southern region of Iraq as well as load demands were demonstrated and discussed in this research. Furthermore, the sun path, solar angles and solar radiations were considered in this study, in addition to the mathematical calculations of optimum tilt angles. The methodology used in this study was based upon theoretical and online measures of real-time weather factors, solar angles, solar radiations and model properties of the examined system. The results and factors of different systems including: peak sun hours per day, dc to ac derate factors, tilt angles, solar radiations and power production were compared to multiple similar research elements that were accomplished around the same region and some other countries. The study concluded that solar tracking system absorbs more radiations and produces an annual production of 15–30% higher than fixed tilt angle system.</span>

Style APA, Harvard, Vancouver, ISO itp.

35

Majeed, Abid, Tariq Javed i Abuzar Ghaffari. "A computational study of Brownian and thermophoresis effects on nonlinear radiation in boundary-layer flow of Maxwell nanofluid initiated due to elongating cylinder". Canadian Journal of Physics 95, nr 10 (październik 2017): 969–75. http://dx.doi.org/10.1139/cjp-2016-0790.

Pełny tekst źródła

Streszczenie:

In this article, attention is paid to investigating the effects of nonlinear thermal radiations for Maxwell nanofluid flow, flowing due to elongating cylinder. For a better understanding of variations in heat transfer, nonlinear heat generation is also considered. The equations of flow, heat and mass transfer due to incorporation of nanoparticles, are modeled through Navier–Stokes, energy, and concentration equations. The reduced partial differential equations are transformed into dimensionless ordinary differential equations with the help of appropriate transformations. The reduced system of ordinary differential equations is simulated by means of efficient technique, namely, the shooting method. Significant difference in the heat transfer enhancement can be observed graphically through temperature profiles and Nusselt number. From the obtained results, finally it is concluded that nonlinear radiation provides better heat transfer rate at the surface of the cylinder as compared to linear or absence of radiation effects.

Style APA, Harvard, Vancouver, ISO itp.

36

Gao, Pengfei, i Rui Yang. "Generating Different Polarized Multiple Vortex Beams at Different Frequencies from Laminated Meta-Surface Lenses". Micromachines 13, nr 1 (30.12.2021): 61. http://dx.doi.org/10.3390/mi13010061.

Pełny tekst źródła

Streszczenie:

We demonstrate the generation of multiple orbital angular momentum (OAM) vortex beams with different radiating states at different frequencies through a laminated meta-surface lens consisting of a dual polarized meta-array interconnected with a frequency selective meta-array. The co-linearly polarized (LP) waves from the source can directly penetrate the meta-surface lens to form multiple OAM vortex beams at one frequency. On the other hand, the meta-surface lens will be capable of releasing the cross-LP counterparts at another frequency with high-efficient polarization conversions to have multiple OAM vortex radiations with different radiating directions and vortex modes. Our design, using laminated meta-surface lens to synthesize multiple OAM vortex beams with orthogonal polarizations at different frequencies, should pave the way for building up more advanced vortex beam communication system with expanded diversity of the meta-device.

Style APA, Harvard, Vancouver, ISO itp.

37

Cuccurullo, Vincenzo, Giuseppe Danilo Di Stasio, Giuseppe Lucio Cascini, Gianluca Gatta i Cataldo Bianco. "The Molecular Effects of Ionizing Radiations on Brain Cells: Radiation Necrosis vs. Tumor Recurrence". Diagnostics 9, nr 4 (24.09.2019): 127. http://dx.doi.org/10.3390/diagnostics9040127.

Pełny tekst źródła

Streszczenie:

The central nervous system (CNS) is generally resistant to the effects of radiation, but higher doses, such as those related to radiation therapy, can cause both acute and long-term brain damage. The most important results is a decline in cognitive function that follows, in most cases, cerebral radionecrosis. The essence of radio-induced brain damage is multifactorial, being linked to total administered dose, dose per fraction, tumor volume, duration of irradiation and dependent on complex interactions between multiple brain cell types. Cognitive impairment has been described following brain radiotherapy, but the mechanisms leading to this adverse event remain mostly unknown. In the event of a brain tumor, on follow-up radiological imaging often cannot clearly distinguish between recurrence and necrosis, while, especially in patients that underwent radiation therapy (RT) post-surgery, positron emission tomography (PET) functional imaging, is able to differentiate tumors from reactive phenomena. More recently, efforts have been done to combine both morphological and functional data in a single exam and acquisition thanks to the co-registration of PET/MRI. The future of PET imaging to differentiate between radionecrosis and tumor recurrence could be represented by a third-generation PET tracer already used to reveal the spatial extent of brain inflammation. The aim of the following review is to analyze the effect of ionizing radiations on CNS with specific regard to effect of radiotherapy, focusing the attention on the mechanism underling the radionecrosis and the brain damage, and show the role of nuclear medicine techniques to distinguish necrosis from recurrence and to early detect of cognitive decline after treatment.

Style APA, Harvard, Vancouver, ISO itp.

38

Basi, S., LP Subedi, GB KC i NR Adhikari. "Cytogenetic Effects of Gamma Rays on Indica Rice Radha-4". Journal of the Institute of Agriculture and Animal Science 27 (1.05.2006): 25–36. http://dx.doi.org/10.3126/jiaas.v27i0.692.

Pełny tekst źródła

Streszczenie:

The present study was conducted to understand the effects of different doses of radiations by gamma rays of Co60 on cytogenetics of indica rice, Radha-4 at the Central Lab, Institute of Agriculture and Animal Science, Rampur, Nepal. The immature PMC of M1 generation plants were analyzed performing the usual smearing and squashing technique. Radiation had a significant effect causing different types of cytogenetic aberrations, such as univalent and multivalent association of chromosomes, chromatin-bridges, laggards, fragments, stickiness, and multinucleated cells. An increasing number of aberrant cells with increasing dose of radiation was identified. The greatest share of aberration was identified due to multivalent association as a result of translocation followed by bridges and laggards, and the least effect for the stickiness of the chromosomes. Finally, 35 KR doses of gamma rays was the most potent dose inducing cytogenetic aberrations in meiotic pollen mother cell of rice compared to other dose spectrum.J. Inst. Agric. Anim. Sci. 27:25-36 (2006)

Style APA, Harvard, Vancouver, ISO itp.

39

WANG, Y. C., S. Y. HSU, C. S. HWANG, J. Y. HWANG, W. K. LAU, F. Y. LIN, T. T. YANG i S. RIMJAEM. "GENERATION OF ULTRA-SHORT ELECTRON BUNCHES FOR LIGHT SOURCE RESEARCH". International Journal of Modern Physics B 21, nr 03n04 (10.02.2007): 430–37. http://dx.doi.org/10.1142/s0217979207042215.

Pełny tekst źródła

Streszczenie:

An S-band thermionic 1.5-cell rf gun injector system is being built at NSRRC for Taiwan Photon Source (TPS) booster. At optimized field ratio, an electron beam with linear energy chirp can be generated by the rf gun. The beam is then compressed by an alpha magnet such that ultra-short electron bunches at femto-second bunch length can be obtained. Particle dynamics has been studied for an rf gun with nose cone at the cathode, simulation results show that 74 pC bunches at about 97 fs is achievable. Some of the critical components such as the rf gun and alpha magnet have been fabricated and being tested in house. Experiments for intense coherent THz radiations and tunable femto-second X-ray from ultra-short bunches are being proposed as future applications.

Style APA, Harvard, Vancouver, ISO itp.

40

Igoshin, Valerii I., i S. Yu Pichugin. "Generation of the fundamental tone and first overtone radiations in a pulsed H2— F2laser". Quantum Electronics 27, nr 5 (31.05.1997): 465–67. http://dx.doi.org/10.1070/qe1997v027n05abeh000964.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

Hussain, Muzamil, Jifeng Cui, Umer Farooq, Mohammed Elamin Ahmed Rabie i Taseer Muhammad. "Nonsimilar Modeling and Numerical Simulations of Electromagnetic Radiative Flow of Nanofluid with Entropy Generation". Mathematical Problems in Engineering 2022 (1.02.2022): 1–20. http://dx.doi.org/10.1155/2022/4272566.

Pełny tekst źródła

Streszczenie:

Electromagnetic water/CNTs nanofluid flow across a convectively heated moving surface is reported in this communication. Aspect of thermal radiations is considered for heat transport analysis. The concept of nonsimilar boundary layer is executed to simplify the convoluted mathematical expressions. Also, an entropy generation model is considered since its reduction minimizes the loss of available energy, which improves thermal efficiency. The governing model is reduced to a dimensionless system by using an appropriate nonsimilarity transformation. The numerical solution for the velocity and temperature profiles has been obtained by implementing local nonsimilarity via finite difference based Matlab algorithm bvp4c for various quantities of the main emerging parameters. The outcomes are depicted in tabular and graphical formats to analyze impacts of different geometrical, thermophysical, and dynamical factors on temperature, velocity, frictional drag, entropy generation (EG), Nusselt number, and the Bejan number. The temperature profile is seen to rise with Biot number and thermal radiation. Higher radiation parameters and nanoparticle concentrations cause an increase in entropy generation. Horizontal plate with the wedge angle m = 0 is the optimal geometry for minimizing entropy generation. The increase in the values electric field parameter leads to the rise in the skin friction coefficient. Also, Nusselt number declines when magnetic parameter and Eckert number are increase. The authors discussed the local nonsimilarity approach for simulating the dimensionless nonsimilar structure. To the best of authors’ knowledge, no such study has yet been published in the literature. To show the originality of results, the current numerical findings are compared with the published research for some limiting cases and are found to be in excellent alignment. This study could be useful for examining the impacts of nanofluids in a thermal transport analysis.

Style APA, Harvard, Vancouver, ISO itp.

42

Khan, Wahid, Umar Khan, Adnan, Basharat Ullah, Naveed Ahmed, Ilyas Khan, Aisha M. Alqahtani i Md Nur Alam. "The Effects of Magneto-Radiative Parameters on the Heat Transfer Mechanism in H2O Composed by Cu-Al2O3 Hybrid Nanomaterial: Numerical Investigation". Mathematical Problems in Engineering 2022 (4.05.2022): 1–10. http://dx.doi.org/10.1155/2022/3098781.

Pełny tekst źródła

Streszczenie:

The analysis of thermal performance in second generation of nanofluids (hybrid nanofluids) attained much attention of the researchers, scientists, engineers, and industrialists. These fluids have ultra-high thermal characteristics due to which their broad applications could be found in many areas of technological world. Therefore, a novel analysis regarding the heat transfer is conducted over a stretched surface by considering combined convection, thermal radiations, and magnetic field. The hybrid nanofluid is synthesized by Cu-Al2O3 guest hybrid-nanomaterial and host liquid H2O. The hybrid flow model is solved numerically and decorated the results over the region of interest. It is drawn that the velocity drops by increasing the strength of Cu-Al2O3 fraction and applied Lorentz forces. Furthermore, the thermal performance of Cu-Al2O3/H2O augmented against stronger thermal radiations, volumetric fraction, and magnetic field effects.

Style APA, Harvard, Vancouver, ISO itp.

43

Romeiras, Maria M., Ana Rita Pena, Tiago Menezes, Raquel Vasconcelos, Filipa Monteiro, Octávio S. Paulo i Mónica Moura. "Shortcomings of Phylogenetic Studies on Recent Radiated Insular Groups: A Meta-Analysis Using Cabo Verde Biodiversity". International Journal of Molecular Sciences 20, nr 11 (6.06.2019): 2782. http://dx.doi.org/10.3390/ijms20112782.

Pełny tekst źródła

Streszczenie:

Over the previous decades, numerous studies focused on how oceanic islands have contributed to determine the phylogenetic relationships and times of origin and diversification of different endemic lineages. The Macaronesian Islands (i.e., Azores, Madeira, Selvagens, Canaries, and Cabo Verde), harbour biotas with exceptionally high levels of endemism. Within the region, the vascular plants and reptiles constitute two of the most important radiations. In this study we compare relevant published phylogenetic data and diversification rates retrieved within Cabo Verde endemic lineages and discuss the importance of choosing appropriate phylogeny-based methods to investigate diversification dynamics on islands. From this selective literature-based review, we summarize the software packages used in Macaronesian studies and discuss their adequacy considering the published data to obtain well-supported phylogenies in the target groups. We further debate the importance of Next Generation Sequencing (NGS), to investigate the evolutionary processes of diversification in the Macaronesian Islands. Analysis of genomic data provides phylogenetic resolution for rapidly evolving species radiations, suggesting a great potential to improve the phylogenetic signal and divergence time estimates in insular lineages. The most important Macaronesian reptile radiations provide good case-studies to compare classical phylogenetic methods with new tools, such as phylogenomics, revealing a high value for research on this hotspot area.

Style APA, Harvard, Vancouver, ISO itp.

44

Natraj, K. S. Reddy i B. N. Rao. "Investigation of Variable Wind Loads and Shape Accuracy of Reflectors in Parabolic Trough Collector". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, nr 1 (19.12.2022): 1495–504. http://dx.doi.org/10.38208/acp.v1.681.

Pełny tekst źródła

Streszczenie:

Concentrated solar power is the technology involving reflectors which reflects the solar radiation and concentrates the radiations onto a receiver which absorbs the solar radiation and rises the temperature of the fluid flowing through it and the fluid is further used for process heating or power generation. Solar parabolic trough is the most established technology among the concentrated solar power technologies. For the optimization of the technology it is important to optimize the parabolic trough collectors from structural point of view as even gravity load is observed to cause a substantial effect on the shape of the reflector. Shape accuracy of the reflector is measured in terms of slope deviation. The slope deviation induced due to gravity and wind loads causes a change in optical and thermal efficiencies. The paper presents the study on pressure distribution at the surface of parabolic trough collector under different wind velocity, angle of attack of wind and orientation of the trough. Further, the pressure values over the trough surface are used to estimate the shape errors for the surface of the trough.

Style APA, Harvard, Vancouver, ISO itp.

45

Garrigues, S., A. Olioso, D. Carrer, B. Decharme, E. Martin, J. C. Calvet, S. Moulin i O. Marloie. "Impact of climate, vegetation, soil and crop management variables on multi-year ISBA-A-gs simulations of evapotranspiration over a Mediterranean crop site". Geoscientific Model Development Discussions 8, nr 2 (26.02.2015): 2053–100. http://dx.doi.org/10.5194/gmdd-8-2053-2015.

Pełny tekst źródła

Streszczenie:

Abstract. Generic land surface models are generally driven by large-scale forcing datasets to describe the climate, the surface characteristics (soil texture, vegetation dynamic) and the cropland management (irrigation). This paper investigates the errors in these forcing variables and their impacts on the evapotranspiration (ET) simulated from the Interactions between Soil, Biosphere, and Atmosphere (ISBA-A-gs) land surface model over a 12 year Mediterranean crop succession. We evaluate the forcing datasets used in the standard implementation of ISBA over France where the model is driven by the SAFRAN high spatial resolution atmospheric reanalysis, the Leaf Area Index (LAI) cycles derived from the Ecoclimap-II land surface parameter database and the soil texture derived from the French soil database. For climate, we focus on the radiations and rainfall variables and we test additional datasets which includes the ERA-Interim low spatial resolution reanalysis, the Global Precipitation Climatology Centre dataset (GPCC) and the MeteoSat Second Generation (MSG) satellite estimate of downwelling shortwave radiations. The methodology consists in comparing the simulation achieved using large-scale forcing datasets with the simulation achieved using local observations for each forcing variable. The relative impacts of the forcing variables on simulated ET are compared with each other and with the model uncertainties triggered by errors in soil parameters. LAI and the lack of irrigation in the simulation generate the largest mean deviations in ET between the large-scale and the local-scale simulations (equivalent to 24 and 19 months of ET over 12 yr). The climate induces smaller mean deviations equivalent to 7–8 months of ET over 12 yr. The soil texture has the lowest impact (equivalent to 3 months of ET). However, the impact of errors in the forcing variables is smaller than the impact triggered by errors in the soil parameters (equivalent to 27 months of ET). The absence of irrigation which represents 18% of cumulative rainfall over 12 years induces a deficit in ET of 14%. It generates much larger variations in incoming water for the model than the differences in rainfall between the reanalysis datasets. ET simulated with the Ecoclimap-II LAI climatology is overestimated by 18% over 12 years. This is related to the overestimation of the mean LAI over the crop cycle which reveals inaccurate representation of Mediterranean crop cycles. Compared to SAFRAN, the use of the ERA-I reanalysis, the GPCC rainfall and the downwelling shortwave radiation derived from the MSG satellite have little influence on the ET simulation performances. The error in yearly ET is mainly driven by the error in yearly rainfall and to a less extent by radiations. The SAFRAN and MSG satellite shortwave radiation estimates show similar negative biases (−9 and −11 W m−2). The ERA-I bias in shortwave radiations is 4 times smaller at daily time scale. Both SAFRAN and ERA-I underestimate longwave downwelling radiations by −12 and −16 W m−2, respectively. The biases in shortwave and longwave radiations show larger inter-annual variation for SAFRAN than for ERA-I. Regarding rainfall, SAFRAN and ERA-I/GPCC are slightly biased at daily and longer time scales (1 and 0.5% of the mean rainfall measurement). The SAFRAN rainfall estimates are more precise due to the use of the in situ daily rainfall measurements of the Avignon site in the reanalysis.

Style APA, Harvard, Vancouver, ISO itp.

46

TALEB, M., G. FABRE, R. STRINGAT, J. d'INCAN i C. EFFANTIN. "GENERATION OF COHERENT IR, VISIBLE AND UV RADIATIONS BY TWO-PHOTON PUMPING IN ATOMIC BARIUM". Le Journal de Physique Colloques 48, nr C7 (grudzień 1987): C7–577—C7–579. http://dx.doi.org/10.1051/jphyscol:19877137.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

47

Girish, T. E., S. Aranya i N. G. Nisha. "Photovoltaic power generation using albedo and thermal radiations in the satellite orbits around planetary bodies". Solar Energy Materials and Solar Cells 91, nr 15-16 (wrzesień 2007): 1503–4. http://dx.doi.org/10.1016/j.solmat.2007.03.013.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

48

Xu, W., i C. Zhang. "Generation of tunable hypersonic phonons from two-dimensional electron gases under free-electron laser radiations". Europhysics Letters (EPL) 42, nr 2 (15.04.1998): 191–96. http://dx.doi.org/10.1209/epl/i1998-00229-y.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

49

Barshile, J. D. "Frequency and Spectrum of Induced Viable Macromutations in Chickpea (Cicer arietinum L.) Cultivar ‘Vishwas’". International Letters of Natural Sciences 30 (grudzień 2014): 1–10. http://dx.doi.org/10.18052/www.scipress.com/ilns.30.1.

Pełny tekst źródła

Streszczenie:

Present investigation was undertaken to study the frequency and spectrum of induced viable macromutations employing SA, EMS and gamma radiation in chickpea (Cicer arietinum L.) cultivar Vishwas (Phule G 5). The seeds of chickpea, cultivar Vishwas were treated with three different concentrations / doses of SA (2, 3 and 4 mM), EMS (8, 12 and 16 mM) and gamma radiations (400, 500 and 600 Gy). The mutagen administered seeds were sown in experimental fields to raise M1 progeny. Seeds of M1 plants and control were harvested separately and sown to raise M2 population. The M2 progeny were screened for viable macromutaions. A wide spectrum of viable macromutations was isolated in the M2 generation. In all twenty four different types of viable morphological macromutations were observed. These included 7 types of plant type mutations and 6 types of leaf mutations, 1 types of flower mutation, 5 types of pod mutation and 5 types of seed mutations. Results indicated that all mutagenic treatments were effective in inducing viable mutations in chickpea, during M2 generation. Differences in response to different mutagens were observed in the spectrum and frequency of viable mutations. Some mutation types occurred more frequently than others. The frequency and spectrum of viable mutations were relatively high with EMS followed by gamma radiation and SA. In the present investigation, an attempt has been made for increasing frequency and spectrum of locally important chickpea cultivar ‘Vishwas’ employing chemical and physical mutagens.

Style APA, Harvard, Vancouver, ISO itp.

50

Barshile, J. D. "Frequency and Spectrum of Induced Viable Macromutations in Chickpea (<i>Cicer arietinum</i> L.) Cultivar ‘Vishwas’". International Letters of Natural Sciences 30 (14.12.2014): 1–10. http://dx.doi.org/10.56431/p-l1h206.

Pełny tekst źródła

Streszczenie:

Present investigation was undertaken to study the frequency and spectrum of induced viable macromutations employing SA, EMS and gamma radiation in chickpea (Cicer arietinum L.) cultivar Vishwas (Phule G 5). The seeds of chickpea, cultivar Vishwas were treated with three different concentrations / doses of SA (2, 3 and 4 mM), EMS (8, 12 and 16 mM) and gamma radiations (400, 500 and 600 Gy). The mutagen administered seeds were sown in experimental fields to raise M1 progeny. Seeds of M1 plants and control were harvested separately and sown to raise M2 population. The M2 progeny were screened for viable macromutaions. A wide spectrum of viable macromutations was isolated in the M2 generation. In all twenty four different types of viable morphological macromutations were observed. These included 7 types of plant type mutations and 6 types of leaf mutations, 1 types of flower mutation, 5 types of pod mutation and 5 types of seed mutations. Results indicated that all mutagenic treatments were effective in inducing viable mutations in chickpea, during M2 generation. Differences in response to different mutagens were observed in the spectrum and frequency of viable mutations. Some mutation types occurred more frequently than others. The frequency and spectrum of viable mutations were relatively high with EMS followed by gamma radiation and SA. In the present investigation, an attempt has been made for increasing frequency and spectrum of locally important chickpea cultivar ‘Vishwas’ employing chemical and physical mutagens.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Radiations generation”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych