Electrodynamics in e⁻ linacs

We report a new calculation of electron beam acceleration along linac using fundamental electrodynamics as basis. Following laws are considered: increasing of work equals multiplication of force to elementary interval; power equals work growth over time interval; force acting on charge equals charge value multiplied to electric field value. Using electrodynamic characteristic, series impedance, equaled a square of electric eld value divided by power, and also taking into account laws mentioned above, an equation for the electric field radiated by the beam is calculated. A transient process of electric field radiated by beam is considered.Рассмотрен расчет ускорения сгустков в линейных ускорителях электронов, основанный на постулатах электродинамики. Перечислены основные постулаты: увеличение работы равно произведению силы на элемент пройденного расстояния; мгновенная мощность равна отношению прироста работы на отрезок времени; сила, действующая на заряд, равна величине заряда, умноженного на напряженность электрического поля. Используя электродинамическую характеристику, последовательное сопротивление круглого диафрагмированного волновода, равное отношению квадрата напряженности электрического поля к мгновенной мощности, и выше названные постулаты электродинамики, получено выражение для электрического поля излучения. Рассмотрен переходный процесс поля излучения цуга сгустков.Розглянуто розрахунок прискорення згусткiв у лiнiйних прискорювачах електронiв, оснований на постулатах електродинамiки. Перелiченi основнi постулати: збiльшення роботи дорiвнює здобутку сили на елемент пройденої вiдстанi; миттєва потужнiсть дорiвнює вiдношенню приросту роботи на вiдрiзок часу; сила, дiюча на заряд, рiвна величинi заряду, помноженого на напруженiсть электричного поля. Використовуючи електродинамiчну характеристику, послiдовний опiр круглого дiафрагмованого хвильопровода, який дорiвнює вiдношеннию квадрата напруженостi електричного поля на миттєву потужнiсть, та перелiченi вище постулати електродинамiки, отриманоно вираз для електричного поля випромiнювання. Розглянуто перехiдний процес поля випромiнювання цуга сгусткiв

A critical evaluation of the multi-item microbial challenge test in ophthalmic disinfectant testing

The Multi-item Microbial Challenge Test (MIMCT) is a stringent, carrier assay of the disinfecting efficacy of a contact lens care regimen. The test involves four steps: 1) in vitro contamination of contact lenses in the presence of organic load; 2) cleansing the contact lens by mechanical rubbing and subsequent rinsing; 3) disinfection of the cleansed lens; and 4) assaying the contact lens and the disinfecting solutlon for viable mlcroorganlsms. The variability of the Individual steps was evaluated in this study by the Contributions of Elements protocol. The eff icacy of the cleanslng step, whlle reputed to be highly variable, was found to be reproducible and dependent upon the formulation under test. A contact lens disinfecting reglmen must reduce the level of contaminants to approximately l(r CFUnens to enjoy a 95% chance of passing the MIMCT. Thls reflects a 10-log unit reduction from the initial inoculurn of approximately 1CP CFUnens. The stringency of the MIMCT depends on the ability of the recovery system to allow the growth of low numbers of residual challenge microorganisms in the presence of the disinfecting solution. Neutralizers included In the recovery system to lnhlblt the disinfectant are therefore critically important to the stringency of the assay. The design of experiments to evaluate neutralizers speclflcally for the MlMCT Is discussed with suggestions for an improved procedure. Introduction Passing the Multi-item Microbial Challenge Test (MIMCT) is accepted as evidence of a contact lens chemical disinfectionregimen'sefficacy. This test examines the ability of a specific regimen to disinfect a contact lens in the presence of organic load. The test consists of several sequential steps designed to emulate standard contact lens cleaning.(rub and rinse) and disinfection. The lens. with an organic load, is inoculated with high concentrations of microorganism The contaminated lens is then subjected to a regimen that can consist of manual rubbing (cleaning), rinsing, chemical disinfection, and, if necessary, a final rinse. The initial cleaning removes particulate debris from the surface of the lens and may significantly reduce the number o

Effect of fluoride toothpastes on enamel demineralization

BACKGROUND: It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. METHODS: A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1); remineralization solution (group 2); Elmex Anticaries (group 3); Elmex Sensitive (group 4); Blend-a-med Complete (group 5) and Colgate GRF (group 6). Ten teeth of each group were used for the determination of the F(- )content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM) and quantitative energy dispersive X-ray analysis (EDX). RESULTS: The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. CONCLUSION: It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations