Degree Of Evacuation Research Articles

Baseband Modeling of Superconducting RF Cavity in Digital Domain

Modern day particle accelerators use resonating RF cavities to generate high electric field for enhancing the kinetic energy of particles for beam acceleration. These RF cavities are made using normal conducting or superconducting material. A closed loop control electronics is applied to maintain stability of the field gradient inside the cavity in terms of its amplitude and phase. Normal conducting mode has more control bandwidth than the superconducting mode and this makes it a difficult process. Another important requirement for achieving superconductivity is the usage of huge amounts of liquid nitrogen, liquid helium, and high degree of evacuation. Developing and testing of any control electronics for such cavities in poses a big challenge since multiple test iterations are desired, which is not economical or sustainable due to associated infrastructural needs. So, in order to perform iterative design, development and deployment in an economical and sustainable manner, cavity simulators are used to mimic the behavior of the cavity characteristics in terms of its electrical and mechanical parameters. In the present paper, the electrical and mechanical model of a superconducting RF cavity is mathematically built on the Simulink platform of MATLAB. The models are then converted to fixed point format and tested on a FPGA device to develop a digital equivalent of a superconducting RF cavity.

CRITERIA FOR SELECTING AEROSOL PACKAGING AND DETERMINING THE OPTIMUM QUANTITY OF A PROPELLANT

Development of a new generation of functional antiage cosmetics is a most important area of cosmetic industry development. An integral part of such products are biologically active substances (BAS) with essential oils, being among the sources of which. Each essential oil is characterized by a well balanced unique composition of biologically active substances. Development of new cosmetic products consists of correct selection of the required composition of components with required properties and selection of a suitable package, preserving product properties throughout its shelf life. During production of cosmetic products in aerosol package a number of issues are solved, unlike with antiage-products in form of creams in customary tubes. The degree of oxidation-reduction reactions, having negative impact on the properties of essential oils, is substantially reduced. The concentration providing for the optimum degree of evacuation and excess pressure in the packaging are essential issues. The aim of this research is to determine the degree of evacuation of the contents, excess pressure, and mass fraction of a propellant in the product test samples to find the samples of aerosol package with optimum parameters. A number of tests to determine the degree of evacuation of the contents from aerosol package, excess pressure and a mass fraction of a propellant have been performed. The greatest degree of evacuation of products was observed with mass fraction of propellant of 13.79%. Based on the results of the tests for excess pressure in aerosol packaging, it has been found, that with mass fraction of a propellant of 13.79% excess pressure is 0.4 MPa, which was taken as an optimum value. The test showed that the mass of a propellant of 16 g evacuates the product from aerosol package to the maximum extent and does not exceed the acceptable limits for excess pressure (0.2–0.6 MPa)

Modern vacuum systems for steel degassing units

The operating principles, the technical characteristics of the main types of modern vacuum pumps used in steel degassing units, and the peculiarities of using vapor-et and mechanical pumps in industrial practice are considered. It is noted that, in recent years, mechanical pumps are used to provide a higher evacuation rate and degree of evacuation and to reach a decrease in the operating costs on their maintenance and steel degassing.

Evacuation Proctography in Normal Volunteers

Constipated patients evaluated by evacuation proctography may be subjected to vigorous medical therapy or surgery, even colectomy, based on radiographic findings that have been called "abnormal" in the literature. Criteria for normal defecography are not uniformly established, nor has correlation of structural or functional findings with symptoms been clearly documented. We prospectively studied 21 asymptomatic volunteers to assess the frequency of findings in a control population, and to establish a quantitative measure of normal rectal emptying. Standard defecography technique demonstrated rectocele, intussusception, pelvic descent, or puborectalis spasm in 14/21 volunteers (67%). The range of rectal emptying was 12.5% to 100%, with four subjects (19%) evacuating less than or equal to 40% of the barium paste. There was no correlation between severity of radiographic findings and degree of evacuation. Defecography results in patients being considered for symptomatic intervention should be interpreted cautiously, given the wide range of normal variation in a control population.

Magnetic Properties of Sintered NKS Permanent Magnets. (2nd Report)

This report relates to magnetic properties of sintered Alnico type permanent magnet. The effects of history of iron powders, degree of oxidation of iron, nickel, cobalt, and copper powders, degree of evacuation and sintering time, and magnetic field cooling rate were investigated. Forming pressure, sintering temperature, degree of evacuation in sintering process, magnetic field cooling rate (900-700°C) of sintered permanent NKS-3 magnet are 6T/cm2, 1270-1300°C (NKS-1DA : 1350°C), 10 -1-10-3mmHg, 3-13 minute respectively.Carbonyl, reduced (MH-300⋅P) and electrolytic iron powders are adequate for producing sintered NKS permanent magnet, and magnetic properties are improved by reducing iron, nickel, cobalt and copper powders, with hydrogen. At least lhr was necessary at 1300°C for obtaining well sintered product.The best times of magnetic field cooling are 5-7 and 10 min. for titanium and silicon addition respectively. Addition of titanium reduces both remanence and maximum energy product value but increases coercive force.

セレンの基礎的研究（第7報）蒸着膜の電子回折による考察

Electron-diffraction pattern of selenium films,prepared on formvar films by vacuum evaporation, showed three haloes (Photo. 1). When these films were treated for 1 hour at 90°, the pattern changed to a different diffuse one, and then the sharp rings due to the hexagonal lattice appeared with increasing temperature(Photo. 4). For the purpose of discussion on the blocking-layer in selenium rectifying plates, the formation of CdSe was examined after the evaporation of cadmium on these selenium films. In these cases,an interesting change due to electron-bombardment appeared as shown in Photo. 7. The fine powder from the selenium layer of the rectifying plate and the films vaporized in air showed two strong rings whose interplanar spacings d=2.75, 1.57 Å cannot be expected from a hexagonal lattice. From these results, the present writer suggests the existence of an intermediate state in which a tetragonal lattice (a=3.49 Å, c⁄a=1.28) is formed. To investigate the effect of substrates, their temperatures and the degree of evacuation on the formation of evaporated films, cleavage surfaces of rock-salts were chosen as the substrates. When the temperature of the substrate was lower than 100°, haloes were observed on the formvar films, whereas crystallized portions existed on the rock-salt surface. At higher temperature sharp patterns due to crystallization were obtained, but the pattern of the films evaporated at 200° showed the diffuse rings in addition to the sharp ones.

The Oxygen Content of the Atmosphere in Containers of Dried Milk Packed in Nitrogen

Summary The results confirm those previously obtained by direct measurement of the amounts and composition of the container gases, with respect to the relative importance of time, temperature, and degree of evacuation in reducing the oxygen concentration of the container gases. That the amounts of adsorbed gases do not decrease to a great extent with increases in the value of these factors within practical limits is also indicated by the desorption values obtained. If equilibrium had been attained in each case, the rate of decrease of the final oxygen content in the containers should have been of a logarithmic nature, since the percentage oxygen removed in each evacuation is a constant. However, the rate obtained practically is not of a logarithmic nature, due presumably to the fact that the values for the per cent oxygen in the container atmospheres are not equilibrium values. The relatively high efficiency of a second evacuation stage in decreasing the per cent oxygen content of the container gases is indicated. However, the rate of desorption seems to vary with different dried milks; hence, the efficiency of gasing procedures should be established for the product concerned in each case. In our experience the use of two stages of evacuation at 3mm. pressure with a 3- to 4-day intervening holding period will produce a final oxygen concentration in the container of approximately 1 per cent. Increasing the duration of the holding period will reduce further the final oxygen concentration.

A New Method of Measuring Alternating Currents and Electric Oscillations

The method consists of the application of the Crookes and Osborne Reynolds radiometers to the measurement of the R.M.S. values of electric currents. Two types of apparatus are descirbed. In the first of these the heat generated by the passage of the current through a nichrome resistance causes the deflection of a light mica vane attached to the extremity of a suspended beam. In the second type the deflection of a fine fibre is employed. Tables and curves are given connecting the indications of the instruments with the current and with the degree of evacuation.