level lines
Recently Published Documents


TOTAL DOCUMENTS

99
(FIVE YEARS 16)

H-INDEX

11
(FIVE YEARS 1)

2021 ◽  
Vol 3 (6) ◽  
pp. 110-116
Author(s):  
M. N. Haddad ◽  
M. A. Al-Jada

This research is to study the accumulation and combined effect of three salinity levels (750, 1500 and 3750 ppm) and of heavy metals (3.26, 3.2, 2 ppm, 2, and 0.2 of Zn, Cu, Fe, Mn, and Mo, respectively) on growth, yield, and uptake of green pea plants grown in piped hydroponic. Due to freshwater shortages, the use of hydroponic growth system was encouraged and used. The experiment consists of planting green peas from seeds into a 6” PVC piped system. After 2.5 months of growing, the experiment was stopped and plants parts were separated and divided into pods, leaves, stems, and roots, Then, physical, and chemical measurements conducted on them. Results indicated that (1) Salt concentration above 1500 mg/l was detrimental on the growth of green pea, (2) the best growth, yield, and biomass weight were observed at salinity of 750 mg/l, (3) heavy metals had positive effect on stems and roots of plants, but declined effect plant growth in general, (4) lines with nutrient deficiency were deficient in growth too, (5) sodium increased in plant’s organs in response to increased salinity in the feed solution, (6) the largest concentration of copper and zinc were found at the roots of the highest salinity level lines (36.05 and 211.58 mg/kg dry plant, respectively), (7) the hydroponic system proved to be efficient and economical and therefore, it is recommended for use for Palestinian farmers, and (8) results obtained in this study agree with previously published research with extent differences.


2021 ◽  
Vol 21 (3) ◽  
pp. 275-283
Author(s):  
A. A. Dubanov

Introduction. A kinematic model of group pursuit of a set of targets on a plane is considered. Pursuers use a technique similar to parallel approach method to achieve goals. Unlike the parallel approach method, the speed vectors of pursuers and targets are directed arbitrarily. In the parallel approach method, the instantaneous directions of movement of the pursuer and the target intersect at a point belonging to the circle of Apollonius. In the group model of pursuing multiple goals, the pursuers try to adhere to a network of predictable trajectories.Materials and Methods. The model sets the task of achieving goals by pursuers at designated points in time. This problem is solved by the methods of multidimensional descriptive geometry using the Radishchev diagram. The predicted trajectory is a composite line that moves parallel to itself when the target moves. On the projection plane “Radius of curvature — speed value”, the permissible speed range of the pursuer is displayed in the form of level lines (these are straight lines parallel to one of the projection planes). Images of speed level lines are displayed on the projection plane “Radius of curvature — time to reach the goal”. The search for points of intersection of the speed line images and the appointed time level line is being conducted. Along the communication lines, the values of the intersection points are lowered to the plane “Radius of curvature — speed value”. Using the obtained points, we construct an approximating curve and look for the intersection point with the line of the assigned speed. As a result, we get values of the radius of the circle at the predicted line of the trajectory of the pursuer.Results. Based on the results of the conducted research, test programs have been created, and animated images have been made in the computer mathematics system.Discussion and Conclusions. This method of constructing trajectories of pursuers to achieve a variety of goals at a given time values can be in demand by developers of autonomous unmanned aerial vehicles.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2058
Author(s):  
Jordi Fraxedas ◽  
Antje Vollmer ◽  
Norbert Koch ◽  
Dominique de Caro ◽  
Kane Jacob ◽  
...  

The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 805
Author(s):  
Anna Bajorek ◽  
Paweł Łopadczak ◽  
Krystian Prusik ◽  
Maciej Zubko

Magnetic nanocomposites SmCo5/α-Fe were synthesized mechanically by high-energy ball milling (HEBM) from SmCo5 and 5%wt. of α-Fe powders. The X-ray diffraction analysis reveals the hexagonal 1:5 phase as the main one accompanied by the cubic α-Fe phase and 2:17 rhombohedral as the secondary phase. The content of each detected phase is modified throughout the synthesis duration. A significant decrease in crystallite size with a simultaneous increase in lattice straining is observed. A simultaneous gradual reduction in particle size is noted from the microstructural analysis. Magnetic properties reveal non-linear modification of magnetic parameters associated with the strength of the exchange coupling induced by various duration times of mechanical synthesis. The highest value of the maximum energy product (BH)max at room temperature is estimated for samples milled for 1 and 6 h. The intermediate mixed-valence state of Sm ions is confirmed by electronic structure analysis. An increase in the Co magnetic moment versus the milling time is evidenced based on the performed fitting of the Co3s core level lines.


Author(s):  
Alexander Glazman ◽  
Ioan Manolescu

AbstractUniform integer-valued Lipschitz functions on a domain of size N of the triangular lattice are shown to have variations of order $$\sqrt{\log N}$$ log N . The level lines of such functions form a loop O(2) model on the edges of the hexagonal lattice with edge-weight one. An infinite-volume Gibbs measure for the loop O(2) model is constructed as a thermodynamic limit and is shown to be unique. It contains only finite loops and has properties indicative of scale-invariance: macroscopic loops appearing at every scale. The existence of the infinite-volume measure carries over to height functions pinned at the origin; the uniqueness of the Gibbs measure does not. The proof is based on a representation of the loop O(2) model via a pair of spin configurations that are shown to satisfy the FKG inequality. We prove RSW-type estimates for a certain connectivity notion in the aforementioned spin model.


2021 ◽  
pp. 1-24
Author(s):  
Alexander Dmitrievich Bruno ◽  
Alexander Borisovich Batkhin

We propose a method for computing the position of all level lines of a real polynomial in the real plane. To do this, it is necessary to compute its critical points and critical curves, and then to compute critical values of the polynomial (there are finite number of them). Now finite number of critical levels and one representative of noncritical level corresponding to a value between two neighboring critical ones enough to compute. We propose a scheme for computing level lines based on polynomial computer algebra algorithms: Gröbner bases, primary ideal decomposition. Software for these computations are pointed out. Nontrivial examples are considered.


2021 ◽  
pp. 1-36
Author(s):  
Alexander Dmitrievich Bruno ◽  
Alexander Borisovich Batkhin ◽  
Zafar Khaydar ugli Khaydarov

Here we present a theory and 3 nontrivial examples of level lines calculating of real polynomials in the real plane. For this case we implement the following programs of computational algebra: factorization of a polynomial, calculation of the Grobner basis, construction of Newton's polygon, representation of an algebraic curve in a plane. Furthermore, it is shown how to overcome computational difficulties.


2021 ◽  
Vol 256 ◽  
pp. 02019
Author(s):  
Heng Wang

After the high-voltage transmission line is cut off due to a fault, the bearing transmission power will be transferred, which may cause overload. If overload cannot be eliminated quickly and scientifically, it is very likely that the line backup protection will be activated, which will trigger chain trip or even blackout accidents. In view of this, this paper proposed a cross-voltage level optimization load shedding control strategy based on fuzzy analytic hierarchy process. Through step-by-step progression in the three indexes of line overload degree, load importance degree, and unit load shedding cost, the lower-level lines of the overload line are selected for optimal line removal, thus achieving the goal of optimizing load shedding across voltage levels.


2020 ◽  
Vol 499 (1) ◽  
pp. 1-6
Author(s):  
A Farhan ◽  
E N Ercan ◽  
F Tombesi

ABSTRACT A sample of 30 H$_{2}$O extra-galactic maser galaxies with their published HCN(J = 1 − 0) and HCO + (J = 1 − 0) observations has been compiled to investigate the dense gas correlation with H2O maser emission. Our sample number exceeds the size of the previous HCN samples studied so far by a factor of 3, and it is the first study on the possible relation with the dense gas tracer HCO + . We find a strong correlation between normalized H2O maser emission luminosity (LH2O/LCO) and normalized HCO + line luminosity (LHCO + /LCO). Moreover, a weak correlation has been found between LH2O/LCO and normalized HCN line luminosity (LHCN/LCO). The sample is also studied after excluding Luminous and ultraluminous infrared galaxy (U)LIRG sources, and the mentioned correlations are noticeably stronger. We show that ‘dense gas’ fractions as obtained from HCN and HCO + molecules tightly correlate with maser emission, especially for galaxies with normal IR luminosity (LIR < 1011 L⊙) and we show that HCO + is a better ‘dense gas’ tracer than HCN. Further systematic studies of these dense gas tracers with higher transition level lines are vital to probe megamaser physical conditions and to accurately determining how maser emission interrelates with the dense gas.


Sign in / Sign up

Export Citation Format

Share Document