Characteristics of Radiation of a round Waveguide through a Flat Homogeneous Heat Shield

The problem of obtaining an analytical description of the radiation characteristics of a circular waveguide closed by a flat homogeneous dielectric plate is solved. The radiation characteristics include: the radiation field; the conductivity of the aperture radiation; and the fields of surface, flowing, and side waves, as well as energy characteristics. In such a statement, a strict solution of Maxwell’s equations is required. The paper uses the method of integral transformations and the method of eigenfunctions. In this case, the assumption is used that the electrical parameters of the dielectric plate (thermal protection) and the geometric dimensions do not depend on time. The relations describing the directional diagram of a circular waveguide with dielectric thermal protection and taking into account the electrical parameters of thermal protection and its thickness are obtained. Expressions are also obtained for the fields of lateral, surface, and outflow waves, from which it is possible to calculate the power taken away by these fields. Numerical calculations were made for some of the obtained relations. The results showed that the power of the side waves is zero. It also follows from the calculations that the radiation field of surface and flowing waves is absent, that is, their contribution to the directional diagram is not

Primary Au prospecting results in the Logrosán area (Central Iberian Zone, Spain).

The Central Iberian Zone presents an exceptional geological interest for its great exploration potential for a number of elements including gold. Metallogeny within the area is mainly related to regional metamorphism and late magmatic activity during the Variscan orogeny. In 2013-2014 junior company Mineral Exploration Network Ltd. has carried out an extensive prospecting field work with a primarily view to discover Au within the area around Logrosan granitic pluton (Cáceres, Spain). The main output of the survey was a localization and presorting of potentially mineralized territory unites at the extensive spatial scale (more than 240 sq. km). The known gold showings in the Central Iberian zone are considered to be synorogenic with a mainly metamorphic fluid source. As arsenic commonly forms widespread geochemical haloes near practically all orogenic gold deposits and appears to be easily and credibly measured by express analytical methods (XRF), it was selected as one of the major pathfinder elements for the initial prospecting. Designed geochemical survey allowed delineating potential target area with contrastive complex As-W-Zn-Pb anomaly in soil sediments and significant quantities of gold particles in heavy mineral concentrates. Placer gold particles analyses and their typomorphic features confirmed nearby primary gold source existence. The suggested scope of work proved to be efficient for assessing mineralization potential and selecting perspective target areas for a detailed drilling.  La Zona Centro Ibérica muestra un interés geológico excepcional debido a su gran potencial de exploración de gran número de elementos, incluido el oro. La metalogenia en esta área está relacionada con un metamorfismo regional y posterior actividad magmática durante la orogenia Varisca. Durante el periodo 2013-2014, la compañía Mineral Exploration Network Ltd llevó a cabo una prospección importante en el campo con una primera observación de Au dentro del área del plutón granítico de Logrosan (Cáceres, España). El primer objetivo de la campaña fue la localización y acotamiento de la zona potencialmente mineralizada a gran escala (más de 20 Km2). El oro descrito es considerado sinorogénico con una fuente principal relacionada con fluidos metamórficos. Como el arsénico aparece frecuentemente constituyendo geoquímicos halos cerca de la mayoría de los depósitos orogénicos de oro y parecen ser medidos fácilmente mediante métodos analíticos (XRF), fue seleccionado como uno de los principales elementos marcadores para realizar la prospección inicial. Los análisis geoquímicos seleccionados permitieron delimitar la zona de interés mediante el contraste del complejo anómalo As-W-Zn-Pb en los sedimentos del suelo y cantidades significativas de partículas de oro en concentraciones de minerales pesados. Los análisis de las partículas de los placeres de oro y sus características tipomórficas confirmaron inicialmente la presencia de oro. El objetivo inicial de este trabajo consistió en mostrar la eficiencia para tasar el potencial de mineralización y seleccionar las áreas idóneas para realizar perforaciones

The Strength of Masonry Based on the Deformation Characteristics of Its Components

The chapter presents a new approach to determining the strength of masonry reinforced with transverse meshes in mortar joints. The method consists of using the values of the modulus of elasticity and limiting deformations of the stone material, mortar for joints, and both steel and composite reinforcements. An analytical notation is proposed that integrally takes into account the characteristics of the initial materials. The results of physical tests of centrally loaded masonry pillars reinforced with steel and composite meshes are given. To test the masonry, widely used materials were used: solid brick and cement-sand mortar. The values of the bearing capacity, deformations, and internal stresses of the masonry are obtained. It is determined that the stresses in the reinforcing bars of the meshes are unevenly distributed in the horizontal plane of the mortar joint and amount to 20–37% of the design resistance of the mesh material. The strength of masonry reinforced with composite meshes is 65–75% of steel of the same cross section. It is shown that there is a good convergence of test results with the presented analytical dependence

Emission Monitoring Mobile Experiment (EMME): An overview and first results of the St. Petersburg megacity campaign 2019

Global climate change is one of the most important scientific, societal and economic contemporary challenges. Fundamental understanding of the major processes driving climate change is the key problem which is to be solved not only on a global but also on a regional scale. The accuracy of regional climate modelling depends on a number of factors. One of these factors is the adequate and comprehensive information on the anthropogenic impact which is highest in industrial regions and areas with dense population – modern megacities. Megacities are not only “heat islands”, but also significant sources of emissions of various substances into the atmosphere, including greenhouse and reactive gases. In 2019, the mobile experiment EMME (Emission Monitoring Mobile Experiment) was conducted within the St. Petersburg agglomeration (Russia) aiming to estimate the emission intensity of greenhouse (CO$_{2}$, CH$_{4}$) nd reactive (CO, NO$_{x}$) gases for St. Petersburg, which is the largest northern megacity. St. Petersburg State University (Russia), Karlsruhe Institute of Technology (Germany) and the University of Bremen (Germany) jointly ran this experiment. The core instruments of the campaign were two portable Bruker EM27/SUN Fourier transform infrared (FTIR) spectrometers which were used for ground-based remote sensing measurements of the total column amount of CO$_{2}$, CH$_{4}$ and CO at upwind and downwind locations on opposite sides of the city. The NO$_{2}$ tropospheric column amount was observed along a circular highway around the city by continuous mobile measurements of scattered solar visible radiation with an OceanOptics HR4000 spectrometer using the differential optical absorption spectroscopy (DOAS) technique. Simultaneously, air samples were collected in air bags for subsequent laboratory analysis. The air samples were taken at the locations of FTIR observations at the ground level and also at altitudes of about 100 m when air bags were lifted by a kite (in case of suitable landscape and favourable wind conditions). The entire campaign consisted of 11 mostly cloudless days of measurements in March–April 2019. Planning of measurements for each day included the determination of optimal location for FTIR spectrometers based on weather forecasts, combined with the numerical modelling of the pollution transport in the megacity area. The real-time corrections of the FTIR operation sites were performed depending on the actual evolution of the megacity NO$_{x}$ plume as detected by the mobile DOAS observations. The estimates of the St. Petersburg emission intensities for the considered greenhouse and reactive gases were obtained by coupling a box model and the results of the EMME observational campaign using the mass balance approach. The CO$_{2}$ emission flux for St. Petersburg as an area source was estimated to be 89 ± 28 ktkm$^{-2}$ yr $^{-2}$ , which is 2 times higher than the corresponding value in the EDGAR database. The experiment revealed the CH$_{4}$ emission flux of 135 ± 68 tkm $^{-2}$ yr $^{-1}$, which is about 1 order of magnitude greater than the value reported by the official inventories of St. Petersburg emissions (∼ 25 tkm$^{-2}$ yr $^{-1}$ or 2017). At the same time, for the urban territory of St. Petersburg, both the EMME experiment and the official inventories for 2017 give similar results for the CO anthropogenic flux (251 ± 104 tkm $^{-2}$ yr $^{-1}$ s. 410 tkm $^{-2}$ yr $^{-1}$) nd for the NO$_{x}$ anthropogenic flux (66 ± 28 tkm$^{-2}$ yr $^{-1}$ vs. 69 tkm $^{-2}$ yr $^{-1}$)

Optics and Quantum Electronics

Contains table of contents for Section 3 and reports on eighteen research projects.Defense Advanced Research Projects Agency/MIT Lincoln Laboratory Contract MDA972-92-J-1038Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant ECS 94-23737U.S. Air Force - Office of Scientific Research Contract F49620-95-1-0221U.S. Navy - Office of Naval Research Grant N00014-95-1-0715MIT Center for Material Science and EngineeringNational Center for Integrated Photonics Technology Contract DMR 94-00334National Center for Integrated Photonics TechnologyU.S. Navy - Office of Naval Research (MFEL) Contract N00014-94-1-0717National Institutes of Health Grant 9-R01-EY11289MIT Lincoln Laboratory Contract BX-5098Electric Power Research Institute Contract RP3170-25ENEC

Informativity of the Vibration Signal of the Spindle Unit of the Metal Cutting Machine

Monitoring the condition of the spindle units of modern metal-cutting machines by methods of non-selective diagnostics involves the possibility of installing monitoring sensors in places with maximum vibration information. In this regard, the assessment of the informative value of the vibration field of the spindle unit, which can be carried out in advance, taking into account the design features, geometric and dimensional characteristics, is an urgent task. Based on the energy approach, a computational model based on the median planes of the walls is proposed using the example of a universal lathe spindle unit. On the basis of the calculated model, the energy balance equations are drawn up taking into account the conditions for the transmission of vibration power between the walls of the housing. The dependences that allow us to calculate the coefficients that take into account the absorption of vibration energy by the walls of the housing are given. The solution of the energy balance equations made it possible, based on the level of the vibration power flow, to rank the walls of the spindle unit body by information content,. The resulting model of the vibration field can be used to determine the reference values of vibration velocities that are formed from sources in the absence of defects. This will allow for non-selective diagnostics to detect the occurrence of a defect at an early stage, and in the presence of a defect to assess the level of its development

ЭКСПЕРИМЕНТАЛЬНЫЕ ИССЛЕДОВАНИЯ УСТОЙЧИВОСТИ ТОНКОСТЕННЫХ ЦИЛИНДРИЧЕСКИХ ОБОЛОЧЕК СРЕДНЕЙ ДЛИНЫ, ЗАПОЛНЕННЫХ СЫПУЧИМ МАТЕРИАЛОМ, ПРИ КРУЧЕНИИ

Экспериментальные исследования выполнены с целью изучения влияния сыпучего заполнителя на устойчивость оболочек при кручении. В отечественной и зарубежной литературе не обнаружены нами публикации, где рассматривалось бы устойчивость тонкостенных оболочек, заполненных сыпучим материалом, при кручении. Для выполнения экспериментов разработана и изготовлена специальная установка, позволяющая испытывать образцы на кручение, на изгиб и на сложное нагружение, нагружая образцы соответствующим образом. До испытаний производился отбор образцов на отсутствие дефектов в виде вмятин, овальности, разностенности, постоянства размеров поперечного сечения. Известно, что дефекты образцов существенно влияют на устойчивость. Образцы испытывались длиной 140 мм, 90 мм, 25 мм. Образцы изготавливались глубокой вытяжкой из высокопластичного алюминиевого сплава 3004 в состоянии Н19. В данном случае один конец образцов жестко закреплялся к установке, к другому концу прикладывался крутящий момент, который возрастал до потери устойчивости образцов. В начале и в конце испытания нагружали образцы малыми порциями, чтобы уловить начало движения и начало потери устойчивости. Установка позволяла создавать различные граничные условия образцов. В экспериментах измеряли крутящий момент и угол закручивания. Построены линейные зависимости угла закручивания от крутящего момента. Значит устойчивость терялась в упругости. Для образцов, заполненных сыпучим заполнителем, в начале процесса закручивания имело место нелинейная зависимость между крутящим моментом и углом закручивания. Это связано с возникновением сил трения между заполнителем и внутренней стенкой образцов, которые создавали противодействующий крутящий момент. Затем графики для пустых и заполненных образцов увеличивались параллельно друг другу. Для пустых образцов [1] рассчитывались критические напряжения, критические углы закручивания, число образовавшихся волн, их направление. Получена сходимость расчетных и экспериментальных параметров в пределах 36%. Сыпучий заполнитель, в виде железного порошка увеличивал значение критического крутящего момента до 17%

On the determination of neutron multiplication by the Rossi-alpha method

Introduction. This work contains the results of determining the prompt neutron multiplication factor in the subcritical state of a one-core BFS facility, obtained by the neutron coincidence method, for which the influence of the error in the βeff in determining the multiplication factor turned out to be insignificant. The core of the facility consisted of rods filled with pellets of metallic depleted uranium, 37% enriched uranium dioxide and 95% enriched plutonium, sodium, stainless steel and Al2O3. Stainless steel served as a reflector. Methods. In contrast to the inverse kinetics equation solving (IKES) method, which is convenient for determining reactor subcritical states, the neutron coincidence method practically does not depend on the error in the value of the effective fraction of delayed neutrons βeff. If in the IKES method the reactivity value is obtained in fractions of βeff, i.e., from the measurement of delayed neutrons, the neutron coincidence method is based on the direct measurement of the value (1 – kσp)2, where is the effective multiplication factor by prompt neutrons. The total multiplication factor is defined as keff = kσp + βeff. If, for example, keff ≈ 0.9 (which is typical for determining the fuel burnup campaign), then it is the error in determining kσp that is the main one in comparison with the error in βeff. Thus, a 10% error in βeff of 0.003–0.004 (typical for plutonium breeders) will make a contribution to the error 1 – keff equal to 1 – kσp + βeff ≈ 0.00035, i.e., approximately 0.35%, but not 10%, as in the IKES method. Rossi-alpha measurements were carried out using two 3He counters and a time analyzer. The measurement channel width Δt was 1.0 μs. From these measurements, the value of the prompt neutron multiplication factor was obtained. In this case, the space-isotope correlation factor for the medium with a source was calculated using the following values: Φ(x) – solutions of the inhomogeneous equation for the neutron flux and Φ+(x) – solutions of the ajoint inhomogeneous equation. Results. The authors also present a comparison of the results of the Rossi-alpha experiment and measurements of the BFS-73 subcritical facility by the standard IKES method in determining the multiplication factor value. The data of the IKES method differ insignificantly from the results of the Rossi-alpha method over the entire range of changes in the subcriticality with an increase in the subcriticality of the BFS-73 one-core facility. Conclusion. It was impossible to apply the neutron coincidence method to fast reactors; however, the method turned out to be quite workable on their models created at the BFS facility, which was successfully demonstrated in this study

Ensuring radiation safety during dismantling, transportation and long-term storage of the SM-3 research reactor core

Described shortly here is a procedure of demounting, removal, transport and long-term storage of the SM-3 core, based on the previous experience of reactor refurbishment undertaken in 1991. Prior to performing refurbishment, computations and calculated data analysis were performed to prove radiation safety of this work, which included estimation of the activity level for activation products in the structural materials of the nuclear research reactor core and the radiation conditions at different stages of its handling. As evidenced by the calculated data, the activity of the main dose-forming radionuclide 60Co attains equilibrium in about 12 years of radiation exposure. Taking into account the fact that the time period between two refurbishments was longer than 12 years, the calculated values of the equivalent dose rate were normalized to the radiation monitoring data obtained during the previous refurbishment, taking into account the calculated activity of 60Co radionuclide. The normalization made it possible to confirm reliability of estimates. The obtained activity data of activation products and taking into account the time spent during the SM-3 refurbishment in 1991, the radiation impact on personnel was estimated. Calculated values of the anticipated effective radiation exposure doses to the personnel engaged in the refurbishment revealed that the main limits of the personnel radiation exposure established in accordance with NRB-99/2009 were not exceeded. Comparison of the results of calculating the equivalent dose rate with the results of radiation monitoring at various points allowed us to establish that during the calculation and analytical justification of the radiation safety of work, the assessment of reflected radiation was significantly underestimated. But the radiation monitoring data, personal radiation monitoring, as well as recorded data of automatic radiation monitoring system show that all work was performed in compliance with the requirements of regulatory documents in the field of radiation safety

Influence of a high-frequency pulsed nanosecond diffusion discharge in the nitrogen atmosphere on the electrical characteristics of a CdHgTe epitaxial films

The effect of a high-frequency nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (CMT) epitaxial films is studied. The measurement of the electrophysical parameters of the CMT specimens upon irradiation shows that that the action of pulses of nanosecond volume discharge leads to changes in the electrophysical properties of CMT epitaxial films due to formation of a near-surface high-conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of CMT narrow-band solid solutions and production of structures heterogeneous with respect to conduction