ION GENERATION BY TUNGSTEN FILAMENT FOR PYROELECTRIC PULSED ACCELERATOR

The article is devoted to investigation of ion generation by tungsten filament in vacuum. Electron and ion currents from tungsten filament at different residual air gas pressures are measured and compared. Dependencies of ion and electron currents from tungsten filament on its supply voltage are measured. Production of ions in the vicinity of the filament is discussed. Prospects of tungsten filament’s application in pyroelectric and piezoelectric pulsed accelerators are discussed.

Структура и механизмы образования наноразмерных пленок примесного металла кобальта и никеля в монокристаллах LiF и MgF-=SUB=-2-=/SUB=-

It is investigated the thermal etching of LiF and MgF2 crystals with cobalt and nickel impurities by means of scanning electron microscopy and atomic force microscopy with using decorating. It is shown that impurity inclusions leave the crystal from dislocations. The differences between of thermal etching in vacuum and air atmosphere take place. The crystallographic oriented terraced etch pits are formed after exit of impurities from dislocations. The square thermal etch pits are formed after thermal etching at 750°C in air. The surface impurity nanoscale film is formed at thermal etching. The oxidation of surface impurities observed at thermal etching in air atmosphere or in residual air atmosphere.

Quantitative Analysis of Valve Contribution to the Failure Probability of Carbon Dioxide Suppression System

Carbon dioxide suppression systems are used in nuclear power plants to extinguish oil fires and ensure integrity of critical equipment. In this study, the contributions of the valves in the carbon dioxide suppression system to the failure probability of suppression were quantitatively analyzed, and the failure probability of the fire suppression system applied to the fire Probabilistic Safety Assessment (PSA) was evaluated for appropriateness. Then, a reliability evaluation model was developed in the form of a fault tree, and the reliability data were analyzed for the major component. The failure probability of the carbon dioxide suppression system with early air-release equipment was assessed as 6.22 × 10^-3/demand, which is 2.67 times that of the system without such equipment. The results were attributed to the addition of the diverted line isolation valves and quick exhaust valve to release residual air into the atmosphere before supplying carbon dioxide to the fire area. It was also confirmed that the failure probability of the carbon dioxide suppression system with the early air-release equipment was 15.6% that of the suppression provided by the fire PSA and that the failure probability of suppression by the fire PSA was conservative. There are no reported guidelines in literature for analyzing the reliabilities of carbon dioxide fire suppression systems, and the fire PSA currently use the failure probability of suppression recommended by the NSAC-179L.

Control-Oriented Modeling of Cycle-to-Cycle Combustion Variability at the Misfire Limit in SI Engines

A control-oriented model is presented that can capture the prior-cycle correlation of combustion cycles during conditions with high levels of exhaust gas recirculation (EGR). Combustion events are modeled in discrete time and the dynamic evolution is captured by the residual air, fuel, and inert gas trapped in the combustion chamber. The mathematical formulation of the model is presented together with the calibration procedure to emulate a particular engine operating condition. A cycle-to-cycle system identification methodology is described which allows regressing model parameters from experimental data. Simulations are presented and compared to real engine measurements to show the modeling potential for analysis and control of combustion events.

Analysis on Dynamic Response Characteristics of High-Speed Solenoid Valve for Electronic Control Fuel Injection System

A 3D numerical simulation model of high-speed solenoid valve (HSV) for electronic control fuel injection system (ECFIS) has been developed. The model has been validated experimentally with acceptable maximum errors of 2% and 8.7% in closure response time and open response time, respectively. Effect of assembly parameters such as residual air gap, maximum lift of valve stem, mass of the moving parts, spring stiffness, and spring pretightening force on dynamic response characteristics of HSV has been analyzed in detail using the simulation model, and influence rules of various parameters on dynamic response characteristics have been established. Moreover, the correlation between interaction factors of main influence factors and dynamic response characteristics of HSV has also been analyzed. It is concluded that residual air gap, maximum lift of the valve stem, and spring pretightening force are the main influencing factors on dynamic response characteristics of HSV, and there are obvious interaction effects between them; when two or three of these main influencing factors are adjusted at the same time, the interaction effects should be considered.

Sorption and Desorption of Medicinal Plants

The sorption and desorption of medicinal plants was carried out on a vacuum installation with mercury gates and McBan quartz scales. The measurements were carried out at 293 K and a residual air pressure of 10-3 -10-4 Pa. We studied the sorption and desorption of water vapor at 293 K for medicinal forestry plants - peppermint (Mentha), nettle (Urtica), plantain (Plantago) and zizifora (Ziziphora). The characteristics of the processes of sorption and desorption of medicinal plants were studied: it was found that the specific surface area of the capillaries is 137.26 m2 /g, and the total pore volume for zisphora under convective drying is 0.095 cm3 /g. For plantain, the characteristics of sorption and desorption were revealed: the confirmed specific surface of the capillaries is 92.10 m2 /g, while the total pore volume is 0.250 cm3 /g.

User Satisfaction and Insulin Pump Handling With a Prefilled Insulin Cartridge in Adults and Adolescents With Type 1 Diabetes

Background: This comparative handling study investigated user satisfaction and insulin pump handling with a prefilled insulin cartridge versus a self-filled insulin reservoir in insulin pump users with type 1 diabetes (T1D). Methods: Adult (n = 105) and adolescent (n = 25) participants performed insulin pump preparations using a prefilled insulin cartridge and self-filled insulin reservoir. User satisfaction, insulin pump preparation time, and residual air in infusion set tubing were assessed for each insulin filling method. Post hoc analysis evaluated training time. Results: User satisfaction scores were statistically significantly different in favor of the prefilled insulin cartridge versus the self-filled insulin reservoir (mean [SD]: overall, 4.0 [0.5] vs 3.3 [0.9]; burden on the user, 1.8 [0.6] vs 2.9 [1.0]; user inconvenience, 2.0 [0.7] vs 2.8 [1.1]; device effectiveness, 3.9 [0.7] vs 3.6 [0.9]; all P < .001). Insulin pump preparation time and residual air measurements were significantly different and numerically lower for the prefilled insulin cartridge versus the self-filled insulin reservoir (mean [SD]: preparation time, 124.4 [30.3] vs 237.8 [64.2] seconds, P < .001; residual air, 2.3 [26.3] vs 10.0 [63.3] mm, P = .007). Training time was shorter with the prefilled insulin cartridge versus the self-filled insulin reservoir (mean [min; max]: 193.1 [36; 453] vs 535.8 [124; 992] seconds). Conclusions: Adult and adolescent insulin pump users were more satisfied with the prefilled insulin cartridge versus the self-filled insulin reservoir when preparing an insulin pump. The prefilled insulin cartridge was associated with reduced insulin pump preparation time and reduced training time versus the self-filled insulin reservoir.