SPRINKLER IRRIGATION SYSTEMS: STATE-OF-THE-ART OF KINEMATIC ANALYSIS AND QUANTUM MECHANICS APPLIED TO WATER JETS

2013 ◽  
pp. n/a-n/a
Author(s):  
Daniele De Wrachien ◽  
Giulio Lorenzini ◽  
Marco Medici
2021 ◽  
Vol 37 (2) ◽  
pp. 367-378
Author(s):  
Lin Hua ◽  
Hong Li ◽  
Yue Jiang

HighlightsThe flow behavior of water jets discharged from different orifices was investigated.High-speed photography (HSP) was used to obtain surface structures and spread characteristics of water jets.The deformation process in axis switching related to the corner vortices effect of non-circular jets was researched by numerical simulation.The axis switching of non-circular jets enhances entrainment ability of the jet.ABSTRACT. Low-intermediate pressure sprinkler irrigation systems are important research topics in the field of water-saving irrigation. Non-circular nozzles improve spray uniformity at lower pressures and are key components of sprinkler irrigation systems. In this article, the behavior of discharged water jets from nozzles with circular, square, and equilateral triangular orifices designed with the same flow rate was investigated. High-speed photography (HSP) was used to capture jet characteristics in the near field (z<20D). The largest spread angle was obtained for the square jet, which was on average 37% larger than that of the circular jet. In addition, numerical simulations were performed to analyze the axis-switching process using the large-eddy simulation (LES) method and the coupled level-set and volume of fluid (CLSVOF) method. The axis-switching phenomenon was observed in non-circular jets, in which surrounding air mixed with the jet and promoted the formation of thin diaphragm structures. The deformation process that occurs in axis switching is described according to the simulated vorticity and velocity fields. The research results suggest the axis-switching phenomenon is induced by corner vortex motions produced by the polygonal orifice, which accelerate the decay of the axial velocity and increase the jet entrainment rate. Thus, the effect of corner vortices should be considered in the design of polygonal nozzles. Keywords: Axis switching, High-speed photography, Liquid jet, Low-intermediate pressure sprinkler irrigation, Non-circular nozzle, Numerical simulation.


2018 ◽  
Vol 31 (2) ◽  
pp. 370-378
Author(s):  
JÚLIO JUSTINO DE ARAÚJO ◽  
VANDER MENDONÇA ◽  
MARIA FRANCISCA SOARES PEREIRA ◽  
MATHEUS DE FREITAS SOUZA

ABSTRACT The banana tree is grown in an extensive tropical region throughout the world, usually by small producers. The present work had the objective of evaluating irrigation systems in banana production in the Açu-RN Valley, aiming at alternatives so that they can be recommended to farmers in the Açu Valley region. The experiment was carried out in the area of the School Farm of the IFRN Campus Ipanguaçu, located in the municipality of Ipanguaçu-RN. The experiment was carried out in a randomized complete block design with subdivided plots and eight replications. The irrigation systems were: irrigation, drip irrigation, micro sprinkler and alternative irrigation. The plots were composed of eight useful plants with spacing in double rows 4 x 2 x 2 m. Eight characteristics related to production were evaluated: bunch mass (MC); number of leaves (NP); number of fruits per cluster (NFC); mean mass of the leaves (MMP); diameter of the fruit of the second seed (DF2P); length of the fruit of the second seed (CF2P); mean fruit mass (MMF); productivity (Prod). The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability. In the first cycle of production the sprinkler irrigation system was the one that presented better results the productivity of the Pacovan banana tree; in the 3rd cycle the alternative irrigation system was the one that showed better results the productivity of the banana tree; where the electrical conductivity correlated with the sodium adsorption ratio in the irrigation water, contributed to a moderate limitation of use.


Author(s):  
Arianna Filntisi ◽  
Dimitrios Vlachakis ◽  
George Matsopoulos ◽  
Sophia Kossida

Proteins are an important class of biochemical molecules, as the structural components of animal and human tissue are based on them. Antibodies are proteins that play a crucial role in the preservation of life since they are produced by the body's immune system as a response to harmful substances. The modelling of proteins and antibodies in particular is a vibrant research field which facilitates the design of drugs, a process otherwise demanding in terms of time and resources. A variety of computational methods and tools are being developed towards that goal, among which are hybrid quantum chemical/molecular mechanical methods and three-dimensional antibody modelling. In this review the authors discuss the knowledge concerning proteins and antibodies, as well as the use of quantum mechanics in the simulation of molecular systems and the three-dimensional antibody modelling.


2019 ◽  
Vol 5 (9) ◽  
pp. eaaw9832 ◽  
Author(s):  
Massimiliano Proietti ◽  
Alexander Pickston ◽  
Francesco Graffitti ◽  
Peter Barrow ◽  
Dmytro Kundys ◽  
...  

The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics the objectivity of observations is not so clear, most markedly exposed in Wigner’s eponymous thought experiment where two observers can experience seemingly different realities. The question whether the observers’ narratives can be reconciled has only recently been made accessible to empirical investigation, through recent no-go theorems that construct an extended Wigner’s friend scenario with four observers. In a state-of-the-art six-photon experiment, we realize this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by five standard deviations. If one holds fast to the assumptions of locality and free choice, this result implies that quantum theory should be interpreted in an observer-dependent way.


jpa ◽  
1988 ◽  
Vol 1 (3) ◽  
pp. 196-201 ◽  
Author(s):  
R. W. Elmore ◽  
D. E. Eisenhauer ◽  
J. E. Specht ◽  
J. H. Williams

1974 ◽  
Vol 17 (6) ◽  
pp. 1020-1024
Author(s):  
G. J. Hermann ◽  
G. M. McMaster ◽  
D. W. Fitzsimmons

2018 ◽  
Vol 38 (2) ◽  
pp. 188-196
Author(s):  
Jorge T. Tamagi ◽  
Miguel A. Uribe-Opazo ◽  
Marcio A. Vilas Boas ◽  
Jerry A. Johann ◽  
Luciana P. C. Guedes

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