Misaligned snowplough effect and the electromagnetic counterpart to black hole binary mergers

We estimate the accretion rates produced when a circumprimary gas disc is pushed into the primary supermassive black hole (SMBH) by the tidal force of the decaying secondary during a SMBH merger. Using the 3D Smoothed Particle Hydrodynamics (SPH) code PHANTOM, we extend previous investigations of co-planar discs to the case where the disc and binary orbital planes are misaligned. We consider a geometrically thin disc with inclination angles varying from 1 18 to 180 18 and a binary with mass ratio q = 10 123. We find that discs with small inclination angles (<10 18) produce an increase in luminosity exceeding the Eddington rate. By contrast, discs with inclinations between 20 18 and 30 18 show a less pronounced rise in the accretion rate, whilst discs inclined by 180 18 show no peak in the mass accretion rate. While previous analytic work predicted that the effective tidal torque drops with increasing inclination angle, we show that the misaligned snowplough effect remains important even for angles larger than the disc aspect ratio. The rise in the accretion rate produced by discs inclined at small angles to the binary orbit can produce an electromagnetic counterpart to the gravitational wave signal emitted from final stages of the binary orbital decay

Effect of particle size of starting oxide powders on the performance of doped-lanthanum oxyapatite produced by mechanical alloying followed by microwave sintering

La9.33Si2Ge4O26 oxyapatite powders were synthesized at room temperature through mechanical alloying of La2O3, GeO2 and SiO2 precursor powders with different particle sizes as well as crystal structure in the case of silica powder (crystalline/amorphous). The mechanical alloyed mixtures were subsequently sintered by microwave heating at 1350 C for 1 h in order to obtain dense and homogeneous materials. All sintered materials consisted of the target apatite phase although minor amounts of secondary phases (e.g.La4GeO8) were also present only in samples obtained from micrometric SiO2 powders with a crystalline structure. The microstructure of the materials obtained from nanometric SiO2 with an amorphous structure was found to be more homogenous than the ones obtained from micrometric/crystalline silica. The mechanical behavior of the samples was slightly dependent on the particle size of the precursors and on the SiO2 crystallinity

Multi-messenger observations of supermassive black holes binary mergers

When a circumprimary gaseous disk is pushed into the primary supermassive black hole (SMBH) by the tidal force of the decaying secondary black hole, it can produce an increase in the luminosity. In the case of a disk that lies in the same plane of the SMBHs binary, that luminosity exceeds the Eddington limit. In this paper, we extend these previous investigations to the case of systems misaligned with different mass values for the binary components. Our aim is to probe which mass range can produce stronger electromagnetic counterparts in the last stages of coalescence. We concentrate in geometrically thin disk models and binary SMBHs with mass ratio q = 10 123 . We compare our numerical results with previously obtained analytical results in the literature. Disks misaligned surrounding a primary SMBH can lead to an electromagnetic signature of the gravitational wave signal emitted from final stages of the SMBH's binary orbital decay

Processo saúde-doença: um estudo das representações sociais de trabalhadores com DORT Health-disease process: a study of social representations of workers with WMSDSs

O artigo origina-se de pesquisa que analisou as representações sociais do processo saúde-doença entre trabalhadores portadores de distúrbios osteomusculares relacionados ao trabalho (DORT), usuários do Centro de Referência em Saúde do Trabalhador (CEREST) de Juiz de Fora, MG. O recurso de apreensão das informações foram entrevistas semiestruturadas, realizadas junto a 12 trabalhadoras com idade entre 29 e 55 anos. As informações foram submetidas a análise temática. A partir dos temas de análise, chamados "representação da saúde" e "representação da doença", para essas trabalhadoras, o adoecimento e a incapacidade laboral representam uma lacuna dolorosa e a destruição dos projetos de vida. Os quadros de deterioração das condições de vida e degradação do trabalho, refletidos sobre a saúde das trabalhadoras, nos levam a sustentar que a prevenção dos problemas de saúde que encontraria maior grau de resolução seria o replanejamento da organização do processo de trabalho e da efetiva atuação das políticas públicas de saúde, através de representações simbólicas mais amplas sobre saúde, doença e cura.<br>This paper was based on a study that examined the social representations of health-illness process among workers with work-related musculoskeletal disorders (WMSDs), users of the Reference Center of Occupational Health (CEREST) in the city of Juiz de Fora, state of Minas Gerais. Information was collected through semi-structured interviews with 12 workers, aged between 29 and 55 years. Data were subjected to thematic analysis. The themes of analysis called "representation of health" and "representation of illness" set that, for these workers, illnesses and labor disability represent a painful gap and the destruction of life projects. Tables of deterioration of living conditions and work degradation, reflected on the health of workers, refer us to sustain that the prevention of health problems that would find a higher degree of resolution would be the replanning of work process' organization and effective performance of public health policies, through symbolic representations of broader health, illness and healing