Development of a 200 W CW High Efficiency Traveling Wave Tube at 12 GHz

The design, development, and test results are reported for an experimental PPM focused, traveling-wave tube that produces 235 watts of CW RF power over 85 MHz centered at 12.080 GHz. The tube uses a coupled cavity RF circuit with a velocity taper for greater than 30 percent basic efficiency. Overall efficiency of 51 percent is achieved by means of a nine stage depressed collector designed at NASA Lewis Research Center. This collector is cooled by direct radiation to deep space

Reumatoidartriidi-spetsiifilise elukvaliteediküsimustiku kohandamine Eestis

Krooniliste haigete eluea pikenemine on muutnud aktuaalseks varem suhteliselt vähe tähelepanu pälvinud haigete elukvaliteedi hindamise. Elukvaliteedi hindamisel on neli huvirühma: patsiendid, arstid, ravimitööstus ja poliitikud. Patsiendid ja arstid saavad elukvaliteedi hinnangu alusel valida tõhusama ravimeetodi. Ravimitööstuses võimaldab raviga saavutatud elukvaliteedi paranemine näidata ravimi eeliseid võistleva preparaadi ees ning kiirendada uute ravimite kasutuselevõttu. Poliitikutele on elukvaliteedi hindamine aluseks tervishoiu- ressursside jaotamisel (1)

Study of 42 and 85 GHz coupled cavity traveling-wave tubes for space use

Designs were formulated for four CW, millimeter wavelength traveling-wave tubes having high efficiency and long life. Three of these tubes, in the 42 to 44 GHz frequency region, develop power outputs of 100 to 300 watts with overall efficiencies of typically 45 percent. Another tube, which covers the frequency range of 84 to 86 GHz, provides a power output of 200 watts at 25 percent efficiency. The cathode current density in each design was 1A/sq cm. Each tube includes: metal-ceramic construction, periodic permanent magnet focusing, a two step velocity taper, an electron beam refocusing section, and a radiation cooled three-stage depressed collector. The electrical and mechanical design for each tube type is discussed in detail. The results of thermal and mechanical analyses are presented

Analytical study program to develop the theoretical design of traveling-wave tubes Final report

Design study to develop high efficiency traveling wave tube amplifier for satellite television transmissio

Development of a 75-watt 60-GHz traveling-wave tube for intersatellite communications

This program covers the initial design and development of a 75 watt, 60 GHz traveling-wave tube for intersatellite communications. The objective frequency band was 59 to 64 GHz, with a minimum tube gain of 35 dB. The objective overall efficiency at saturation was 40 percent. The tube, designated the 961H, used a coupled-cavity interaction circuit with periodic permanent magnet beam focusing to minimize the weight. For efficiency enhancement, it incorporated a four-stage depressed collector capable of radiation cooling in space. The electron gun had a low-temperature (type-M) cathode and an isolated anode. Two tubes were built and tested; one feasibility model with a single-stage collector and one experimental model that incorporated the multistage collector

Ethnic Dimensions of Suburbanisation in Estonia

Large scale suburbanisation is a relatively recent phenomenon in East Central Europe and responsible for major socio-spatial changes in metropolitan areas. Little is known about the ethnic dimensions of this process. However, large minority population groups, mainly ethnic Russians, remained into the former member states of the Soviet Union after its dissolution in 1991. We use individual level Estonia Census data in order to investigate the ethnic dimensions of suburbanisation. The results show that ethnic minorities have a considerably lower probability to suburbanise compared to the majority population, and minorities are less likely to move to rural municipalities – the main sites of suburban change – in the suburban ring of cities. Individual characteristics that measure strong ties with the majority population and host society exert a positive effect on ethnic minority suburbanization, and on settling in rural municipalities.suburbanisation, ethnicity, Census data, East Central Europe, Estonia

Housing and Ethnicity in Soviet Tartu

Research on residential and housing inequality in the cities under central planninghas a long tradition. However, previous studies have mostly focused on age and socialsegregation, while ethnic di.fferences have been poorly investigated. This researchclarifies the ethnic di.fferences in housing ownership and living conditions in Tartu,Estonia, in the Sovi et period. We use individual-level data from the 1989 census andmultivariate analysis. Our analysis shows that, first, non-Estonians had better accessta state housing than Estonians. The ethnic di.fferences decrease, but remain significantwhen controlling for compositional di.fferences. Second, it appears that Estonianshad more living space, while non-Estonians lived in more comfortable conditions.Di.fferences in housing ownership and population composition explain most afthe ethnic di.fferences in housing size, but the di.fferences in housingfacilities remain.We argue that both the state policy and the di.fferent traditions and values were responsiblefor the housing di.fferences between Estonians and non-Estonians in Tartuduring the Soviet period. The role af the pre-WWII legacy should be considered as well

New perspectives on ethnic segregation over time and space. A domains approach

The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC [Grant Agreement No. 615159] (ERC Consolidator Grant DEPRIVEDHOODS, Socio-spatial inequality, deprived neighbourhoods, and neighbourhood effects); from the Marie Curie programme under the European Union’s Seventh Framework Programme (FP/2007-2013)/Career Integration [Grant No. PCIG10-GA-2011-303728] (CIG Grant NBHCHOICE, Neighbourhood choice, neighbourhood sorting, and neighbourhood effects), from the Estonian Research Council (Institutional Research Grant IUT2-17 on Spatial Population Mobility and Geographical Changes in Urban Regions); and from the Estonian Science Foundation [Grant Nos. 8774 and 9247].Ethnic segregation has most often been studied at the place of residence, segregation being defined on the basis of the relative presence of different groups within city neighbourhoods. It is increasingly recognized, however, that segregation occurs in different ways in different domains (such as the workplace, leisure, social media, etc.), the residential domain being just one of many in which segregation can occur. In this research note we present the domains approach to segregation and outline some its conceptual, methodological and empirical underpinnings and challenges.Publisher PDFPeer reviewe

Harvestmen (Arachnida: Opiliones) in Estonia: results of the Estonian Malaise Trap Project

The species composition of Estonian harvestmen (Opiliones) was revised based on a critical review of published data and examination of the material from the Estonian Malaise Trap Project (EMTP), which is briefly introduced. Four years of collecting (from 2008 to 2011) with “Czech type”Malaise traps from 15 localities throughout Estonia resulted in 4,102 specimens of 9 species. Two of them, Lophopilio palpinalis (Herbst, 1799) and Leiobunum tisciae (Avram, 1968), were found from Estonia for the first time. Combined with reliable published data, the number of harvestmen species known from Estonia is now set at 12. Distribution and habitat preferences of harvestmen in Estonia were examined subjecting the Malaise trapping data to a quantitative analysis using environmental variables recorded for each trap location. Only tree layer density (i.e. the presence of forest as such) was identified as a significant predictor of harvestmen abundance and diversity which indicates a low degree of habitat specificity in boreo-nemoral harvestmen

Pre-Hire Factors and Workplace Ethnic Segregation

In addition to neighbourhoods of residence, family and places of work play important roles in producing and reproducing ethnic segregation. Therefore, recent research on ethnic segregation and contact is increasingly turning its attention from residential areas towards other important domains of daily interethnic contact. The key innovation of this paper is to clarify the role of immigrants' pre-hire exposure to natives in the residence, workplace and family domains in immigrant exposure to natives in their current workplace. The study is based on Swedish population register data. The results show that at the macro level, workplace neighbourhood segregation is lower than residential neighbourhood segregation. Our micro-level analysis further shows that high levels of residential exposure of immigrants to natives help to reduce ethnic segregation at the level of workplace establishments as well.neighbourhood effects, residential segregation, workplace segregation, intermarriage, longitudinal analysis, Sweden