Spectroscopic properties of large open quantum-chaotic cavities with and without separated time scales

The spectroscopic properties of an open large Bunimovich cavity are studied numerically in the framework of the effective Hamiltonian formalism. The cavity is opened by attaching leads to it in four different ways. In some cases, short-lived and long-lived resonance states coexist. The short-lived states cause traveling waves in the transmission while the long-lived ones generate superposed fluctuations. The traveling waves oscillate as a function of energy. They are not localized in the interior of the large chaotic cavity. In other cases, the transmission takes place via standing waves with an intensity that closely follows the profile of the resonances. In all considered cases, the phase rigidity fluctuates with energy. It is mostly near to its maximum value and agrees well with the theoretical value for the two-channel case. As shown in the foregoing paper \cite{1}, all cases are described well by the Poisson kernel when the calculation is restricted to an energy region in which the average $S$ matrix is (nearly) constant.Comment: 13 pages, 4 figure

The theory of sifting the soil mass when cleaning potatoes on a spiral separator

The removal of soil and impurities is an important problem when harvesting potatoes. and the main reason for this problem is due to the modalities employed to carry out the potatoes mechanical harvesting. The equipments currently implemented on potato harvesters do not always allow to obtain high levels of soil and impurities separation, mainly due to the gluing of the moist soil to the surfaces of the separating organs. The authors have developed a spiral separator of soil clods from potatoes heaps, patented in Ukraine. The purpose of this paper has been to analyze the theory of sifting the soil mass when a spiral separator is used. A mathematical model of the motion of an elementary body along the spiral surface of a potato heap separator has been built. The numerical solution of the model has highlighted that the lowest angular speed (10 rad s-1) of the cleaning rollers allows the greatest amount of sifted soil mass. Field tests carried out confirmed that the developed spiral separator is able to perform the task achieving meaningful values of the efficiency of separation and heap purity. Further field and laboratory tests will be executed in order to improve the set up mathematical model

Mathematical model of the movement of a potato body along the surface of a spiral separator

The potato is grown in over one hundred countries spread over all latitudes, with the most diverse climatic conditions, from the areas near the Arctic Circle to the southern end of the South American continent. The potato is an irreplaceable component of the food tradition of many countries and is the most cultivated species after cereals (wheat, rice and corn). The authors set up and developed a new clod and rubbish spiral separator for potatoes, which is protected by the patent of Ukraine. The operation modalities of this machine are briefly described in the paper. The aim of this study is the development of a mathematical model concerning the movement of a potato body along the surface the spiral separator. In particular, equations are found for determining the coordinates of the position of a potato tuber on the surface of a spiral separator depending on the parameters of the spiral (spiral line) and the size of the tuber. Furthermore, the velocity of tuber movement in the stream formed by the surfaces of two neighboring spirals in the direction of the horizontal, vertical and longitudinal axis are determined. The results of this study will be used in the future to analytically considering the dynamics of movement of a potato tuber on the surface of a spiral separator, taking into account the conditions that exclude its damage

Correlated behavior of conductance and phase rigidity in the transition from the weak-coupling to the strong-coupling regime

We study the transmission through different small systems as a function of the coupling strength $v$ to the two attached leads. The leads are identical with only one propagating mode $\xi^E_C$ in each of them. Besides the conductance $G$, we calculate the phase rigidity $\rho$ of the scattering wave function $\Psi^E_C$ in the interior of the system. Most interesting results are obtained in the regime of strongly overlapping resonance states where the crossover from staying to traveling modes takes place. The crossover is characterized by collective effects. Here, the conductance is plateau-like enhanced in some energy regions of finite length while corridors with zero transmission (total reflection) appear in other energy regions. This transmission picture depends only weakly on the spectrum of the closed system. It is caused by the alignment of some resonance states of the system with the propagating modes $\xi^E_C$ in the leads. The alignment of resonance states takes place stepwise by resonance trapping, i.e. it is accompanied by the decoupling of other resonance states from the continuum of propagating modes. This process is quantitatively described by the phase rigidity $\rho$ of the scattering wave function. Averaged over energy in the considered energy window, $$ is correlated with $1-$. In the regime of strong coupling, only two short-lived resonance states survive each aligned with one of the channel wave functions $\xi^E_C$. They may be identified with traveling modes through the system. The remaining $M-2$ trapped narrow resonance states are well separated from one another.Comment: Resonance trapping mechanism explained in the captions of Figs. 7 to 11. Recent papers added in the list of reference

Phase rigidity and avoided level crossings in the complex energy plane

We consider the effective Hamiltonian of an open quantum system, its biorthogonal eigenfunctions $\phi_\lambda$ and define the value $r_\lambda = (\phi_\lambda|\phi_\lambda)/$ that characterizes the phase rigidity of the eigenfunctions $\phi_\lambda$. In the scenario with avoided level crossings, $r_\lambda$ varies between 1 and 0 due to the mutual influence of neighboring resonances. The variation of $r_\lambda$ may be considered as an internal property of an {\it open} quantum system. In the literature, the phase rigidity $\rho$ of the scattering wave function $\Psi^E_C$ is considered. Since $\Psi^E_C$ can be represented in the interior of the system by the $\phi_\lambda$, the phase rigidity $\rho$ of the $\Psi^E_C$ is related to the $r_\lambda$ and therefore also to the mutual influence of neighboring resonances. As a consequence, the reduction of the phase rigidity $\rho$ to values smaller than 1 should be considered, at least partly, as an internal property of an open quantum system in the overlapping regime. The relation to measurable values such as the transmission through a quantum dot, follows from the fact that the transmission is, in any case, resonant with respect to the effective Hamiltonian. We illustrate the relation between phase rigidity $\rho$ and transmission numerically for small open cavities.Comment: 6 pages, 3 figure

Investigations about the impact of the sowing time and rate of the biomass yield and quality of industrial hemp

ArticleThe aim of this study was to find the optimum sowing rate of industrial hemp (Cannabis sativa L.) and to clarify the impact of the sowing rate on the production of biofuel from hemp biomass in Latvia. Field trials were carried out at the Research and Study Farm ‘Pēterlauki’ of the Latvia University of Agriculture in 2012–2014. The industrial hemp (Cannabis sativa L.) ‘Futura 75’ was sown in a Luvic Endogleyic Stagnosol soil: pHKCl 6.7; P – 52 mg kg-1 ; K – 128 mg kg-1 ; the organic matter content – 21–25 g kg-1 . Hemp was sown in 10-m2 plots, triplicate, on May 8 and 17. The total sowing rate was 20 (100), 30 (150), 40 (200), 50 (250), 60 (300), 70 (350), 80 (400), 90 (450), and 100 (500) kg ha-1 (germinating seeds per 1 m2 ). The plots were fertilised as follows: N – 120 kg ha-1 ; P2O5 – 80 kg ha-1 ; and K2O – 112 kg ha-1 . Hemp was harvested when the first matured seeds appeared. The biometrical indices (height and stem diameter), harvesting time, the amount of fresh and dry biomass, and the fibre content were evaluated. Depending on the sowing rate, the yield of dry matter was on average 9.2–12.1 t ha-1 when hemp was sown at the beginning of May, and 7.9–10.0 t ha-1 when hemp was sown in the middle of May

Remote sensing observations of the coherent and non-coherent ring structures in the vicinity of Lesser Antilles

The North Brazil Current Rings (NBCR) penetration into the Caribbean Sea is being investigated by employing a merged altimeter-derived sea height anomaly (TOPEX/Poseidon, Jason-1 and ERS-1, 2), the ocean surface color data (SeaWiFS) and Global Drifter Program information. Four strategies are being applied to process the data: (1) calculations of the Okubo-Weiss parameter for NBCR identification, (2) longitude-time plots (also known as Hovmöller diagrams), (3) two-dimensional Radon transforms and (4) two-dimensional Fourier transforms. <br><br> A twofold NBCR structure has been detected in the region under investigation. The results have shown that NBC rings mainly propagate into the Caribbean Sea along two principal pathways (near 12° N and 17° N) in the ring translation corridor. Thus, rings following the southern pathway in the fall-winter period can enter through very shallow southern straits as non-coherent structures. A different behavior is observed near the northern pathway (~17° N), where NBC rings are thought to have a coherent structure during their squeezing into the eastern Caribbean, i.e. conserving the principal characteristics of the incident rings. We attribute this difference in the rings' behavior to the vertical scales of the rings and to the bottom topography features in the vicinity of the Lesser Antilles

A mathematical model of the plane-parallel movement of an asymmetric machine-and-tractor aggregate

Technological peculiarities of cultivation and harvesting of some agricultural crops make it necessary to use asymmetric machine-and-tractor aggregates. However, for the time being there is no sufficiently complete, analytical study of the steady movement of such machine-and-tractor aggregates. This necessitates the development of a theory of stable movement of the aggregates which would allow choosing their optimal kinematic and design parameters. On the basis of the results of mathematical simulation, a system of linear differential equations of the second order is obtained describing transverse displacement of the center of masses of the aggregating wheeled tractor and turning of its longitudinal axis of symmetry by some angle around the indicated center of mass, as well as the deviation angle of the rear-trailed harvester from the longitudinal axis of the tractor at any arbitrary moment of time. This system of differential equations can be applied for numerical calculations on the PC, which will make it possible to evaluate the stability of the movement of the asymmetric machine-and-tractor aggregate when it performs the technological process

Research in dynamic transitional processes of functioning of combine harvester hydraulic drives

An analysis of perspective methods is made for diagnosing hydraulic drives, based on the on-board automated tools. Prospects are substantiated for the development of technical diagnostics of agricultural machinery on the basis of on-board electronic means. Special attention is paid to the need for significant research in the direction of creating new diagnostic parameters, adapted to these means, and methods of their measurement. The parameters of the characteristics of changes in the pressure of the working fluid in the hydraulic aggregates in transitional modes of operation of the hydraulic drives are advisable to be used as diagnostic, since the veracity (accuracy) of the parameters, based on them, is not less than 95%. As an example, a method of diagnosing on dynamic transitional modes of operation of the hydraulic drives is given, which is the basis for the development and use of built-in and portable electronic means for conducting CIP diagnostics, which will provide 2-3 times decrease in the labour intensity and the cost of work with at least 85% veracity of diagnosis and the permissible error measurements no more than ± 4%. The novelty of this work lies in the method we have developed for diagnosing the dynamic transient modes of operation of hydraulic drives

Spin rotation for ballistic electron transmission induced by spin-orbit interaction

We study spin dependent electron transmission through one- and two-dimensional curved waveguides and quantum dots with account of spin-orbit interaction. We prove that for a transmission through arbitrary structure there is no spin polarization provided that electron transmits in isolated energy subband and only two leads are attached to the structure. In particular there is no spin polarization in the one-dimensional wire for which spin dependent solution is found analytically. The solution demonstrates spin evolution as dependent on a length of wire. Numerical solution for transmission of electrons through the two-dimensional curved waveguides coincides with the solution for the one-dimensional wire if the energy of electron is within the first energy subband. In the vicinity of edges of the energy subbands there are sharp anomalies of spin flipping.Comment: 9 oages, 7 figure