Experimental investigations of a breadboard model of Hall thruster

Various breadboard models of Hall thrusters are analyzed with a view to optimizing the output parameters which characterize the degree of processing of the working medium and the energy efficiency of the device. It is demonstrated that the channel geometry with the magnetic field uniform along the channel affects only slightly the efficiency of acceleration of ion flow. In a number of working modes, the formation of accelerated ion flow is accompanied by the emergence of pulsations of discharge current, this leading to destructive processes of acceleration and formation of ion flow. The development of a breadboard model with a nonuniform magnetic field along the channel significantly decreasing in the direction of anode with cylindrical space makes possible the elimination of discharge current pulsations in a wide range of parameters. The increase in the density of the flow of working medium by a factor of 1.7 results in a 30% increase in the energy efficiency and provides for the working medium utilization factor of the order of 1.2.     

The Effect of the Angular and Radial Distributions of Trajectories on the Structure of Axisymmetric Electron and Ion Beams with Compensated Charge in a Longitudinal Magnetic Field

The structure of beams with compensated charge is described using a multiflow collisionless model in which the current is split into N interacting tubes of current. The effect of the boundary angular distribution of the tubes of current, as well as of the boundary radial distribution of current, on the configuration of electron and ion beams is studied. It is demonstrated that a crisis of flow arises in the absence of an external magnetic field at a certain value of current. An external longitudinal magnetic field expands the region of noncritical flow and promotes the laminarity of flow. The boundaries of the critical mode are determined for different angular and radial distributions, and the trajectories of the tubes of current in the subcritical and supercritical regions are calculated.     

Reticular inhibition of evoked potentials of the ventro-basal thalamus and somatosensory cortex of the rat brain

In rats immobilized with d-tubocurarine conditioning electrical stimulation (100/s, 300 ms) of the central grey matter, reticular formation of the midbrain and medulla depressed focal potentials in thalamic ventro-basal complex and somatosensory cortex evoked by electrical stimulation of the forelimb or medial meniscus. The average threshold current for conditioning stimulation of these structures was 70, 100 and 120 muA. A comparison of intensity and duration of evoked potentials depression (for two-fold threshold stimulation of the brain stem) is failed to detect any difference between the stimulated structures: immediately after conditioning stimulation the amplitude of the cortical evoked potentials and post-synaptic components of the evoked potentials in the ventro-basal complex were 50-60% less than control amplitude (p less than 0.01) the depression persisting for 0.5-1 s. The presynaptic component of the thalamic evoked potentials was depressed only after three five-fold threshold conditioning stimulation. The brain stem stimulation did not cause any facilitatory effect on focal potentials evoked by maximal and submaximal stimulation of the forelimb or medial lemniscus.     

Effect of pharmacotherapy of affective disorders on the psycho-semantics of alcoholic patients

90 alcoholic patients (II stage of alcoholism) with secondary affective disorders (anxiety, depression) were divided into 4 groups. The patients of the first group received the GABA receptor ligand baclofen during 3 weeks. Sybazon preparation was used in the second group, while the patients of the third group were treated with amitriptyline. Placebo was applied in the forth group. The clinical psychological tests demonstrated that all drugs caused quite effective relief of affective disorders. Psychosemantic tests application showed that the pharmacotherapy caused positive changes in patients of 1-3 groups. These changes touched on both system of personal estimations and relations of personality to himself and to the world around i.e. psychosemantic sphere. Such changes in psychosemantic sphere were not observed in the 4-th group of patients (placebo). Besides it was revealed that each drug caused some specific changes in psychosemantic sphere. The result obtained were supposed to have some theoretical value in comprehension of brain-psychics relations as well as the applied significance for adequate choice of affective disorders pharmacotherapy of alcoholic patients.     

Baseline layout and design of a 0.8 GW reference wind farm in the North Sea

The paper presents a model of a reference wind farm. The model considers the wind and wave climatologies for a specific site from which two different wind farm layouts are derived. These layouts are examined through the effective wake‐enhanced turbulence intensity at the hub height for a given climatology, and a simple model for the influence on capital expenditures is proposed. An electrical design is presented, the cable losses are calculated and the energy yield is determined. An operation and maintenance model is established, and the associated operating expenditure is obtained. All of the models are then summarized in terms of a levelized cost of energy using a numerical simulation tool, which allows the layouts to be compared. The data and models are freely available online for others to use and may serve as a baseline for benchmarking and allow researchers to compare and discuss their results. Copyright © 2017 John Wiley & Sons, Ltd.     

The oxidant and antioxidant systems in patients with stable stenocardia and with a history of small- and large-focus myocardial infarcts

A study was made as well as a comparison of values of the cholesterol (Chs) lipid fractions concentrations, and of those of the lipid peroxidation processes activity (LPP) and the gluthathione antioxidant system (AOS) status in male subjects aged from 45 to 59 years, healthy individuals and patients with stable angina pectoris and myocardial infarction (micro- and macrofocal) during cicatrizing stage (health resort rehabilitation stage). In patients with various forms of IHD total cholesterol is raised as are atherogenic lipoproteins, and atherogenicity index, intensification being noted of LPO along with a considerable decrease in functional potencies of AOS. Similar pattern of changes of LPO and AOS in patients with stable angina pectoris and myocardial infarction (MI) during cicatrization stage certainly warrants correction of these systems not only in acute phase of MI but at the stage of rehabilitation as well.