Resíduos de usinas de concreto como material alternativo para produção de produtos cimentícios: mapeamento sistemático

Concrete waste sludge is a cementitious waste from the treatment of wastewater generated during the washing process of concrete mixer yards and trucks in metering plants. This waste is basically composed of water, aggregates, cement paste and additives used for concrete production. Due to its characteristics, such as high pH and high suspended solids content, this material must be properly managed, since, according to CONAMA Resolution nº. 430, the discharge of effluents into the soil cannot pose pollution risks to surface and groundwater. In recent years, both academia and industry have sought to find solutions that reduce the impact of some productive activities on the environment. Therefore, this article aims to present an overview of research related to the incorporation of concrete sludge in cement products. For this, a systematic literature mapping was performed through the CAPES Periodic database using the search strings “concrete sludge” and “fresh concrete waste”, in order to find the main studies related to the studied slope. Thus, through the mapping performed it was possible to realize that, when compared to other types of waste, the study of concrete residual sludge (LRC) is still recent and the impacts of its use have not been completely clarified, thus highlighting the need for further research. in the area.A lama residual de concreto (LRC) é um resíduo cimentício proveniente do tratamento da água residuária gerada durante o processo de lavagem de pátios e caminhões betoneira em usinas dosadoras. Este resíduo é composto basicamente por água, agregados, pasta de cimento e aditivos utilizados para produção de concreto. Devido as suas características como, por exemplo, elevado pH e alto teor de sólidos suspensos, há de se ter um manejo adequado deste material, visto que, conforme a Resolução CONAMA nº 430, o lançamento de efluentes em solo não poderá representar riscos de poluição às águas superficiais e subterrâneas. Nota-se que nos últimos anos, tanto a academia, quanto a indústria, têm buscado encontrar soluções reduzam o impacto de algumas atividades produtivas sobre o meio ambiente. Assim sendo, este artigo tem como objetivo apresentar um panorama das pesquisas relacionadas com a incorporação da lama residual de concreto em produtos cimentícios. Para tanto, foi realizado um mapeamento sistemático da literatura através da base de dados Periódicos CAPES utilizando as strings de busca “concrete sludge” e “fresh concrete waste”, de forma a encontrar os principais estudos relacionados com a vertente estudada. Assim, através do mapeamento realizado foi possível perceber que, quando comparada com outros tipos de resíduos, o estudo da lama residual de concreto (LRC) ainda é recente e os impactos da sua utilização ainda não foram completamente esclarecidos, ressaltando assim a necessidade de novas pesquisas na área

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Radiation damage and nuclear heating studies in selected functional materials during the JET DT campaign

A new Deuterium-Tritium campaign (DTE2) is planned at JET in the next years, with a proposed 14MeV neutron budget of 1.7×1021, which is nearly an order of magnitude higher than any previous DT campaigns. The neutron and gamma ray fields inside the JET device during DT plasma operations at specific locations have previously been evaluated. It is estimated that a total neutron fluence on the first wall of JET of up to 1020 n/m2 could be achieved, which is comparable to the fluence occurring in ITER at the end of life in the rear part of the port plug, where several diagnostic components will be located.The purpose of the present work is to evaluate the radiation damage and nuclear heating in selected functional materials to be irradiated at JET during DT plasma operation. These quantities are calculated with the use of the MCNP6 code and the FISPACT II code. In particular the neutron and gamma ray fields at specific locations inside the JET device, dedicated to material damage studies, were characterized. The emphasis is on a potential long term irradiation station located close to the first wall at outboard midplane, offering the opportunity to irradiate samples of functional materials used in ITER diagnostics, to assess the degradation of the physical properties. The radiation damage and the nuclear heating were calculated for selected materials irradiated in these positions and for the neutron flux and fluence expected in DTE2. The studied candidate functional materials include, among others, Sapphire, YAG, ZnS, Spinel, Diamond. In addition the activation of the internal irradiation holder itself was calculated with FISPACT. Damage levels in the range of 10-5 dpa were found

Neutronic analysis of JET external neutron monitor response

The power output of fusion devices is measured in terms of the neutron yield which relates directly to the fusion yield. JET made a transition from Carbon wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) during 2010–11. Absolutely calibrated measurement of the neutron yield by JET neutron monitors was ensured by direct measurements using a calibrated 252Cf neutron source (NS) deployed by the in-vessel remote handling system (RHS) inside the JET vacuum vessel. Neutronic calculations were required in order to understand the neutron transport from the source in the vacuum vessel to the fission chamber detectors mounted outside the vessel on the transformer limbs of the tokamak. We developed a simplified computational model of JET and the JET RHS in Monte Carlo neutron transport code MCNP and analyzed the paths and structures through which neutrons reach the detectors and the effect of the JET RHS on the neutron monitor response. In addition we performed several sensitivity studies of the effect of substantial massive structures blocking the ports on the external neutron monitor response. As the simplified model provided a qualitative picture of the process only, some calculations were repeated using a more detailed full 3D model of the JET tokamak

Activation material selection for multiple foil activation detectors in JET TT campaign

In the preparation for the Deuterium-Tritium campaign, JET will operate with a tritium plasma. The T + T reaction consists of two notable channels: (1) T + T -> He-4 + 2n, (2) T + T -> He-5 + n -> He-4 + 2n. The reaction channel (1) is the reaction with the highest branching ratio and a continuum of neutron energies being produced. Reaction channel (2) produces a spectrum with a peak at 8.8 MeV. A particular problem is the ratio between the individual TT reaction channels, which is highly dependent on the energy of the reacting tritium ions. There are very few measurements on the TT spectrum and the study at JET would be interesting. The work is focused on the determination of the spectral characteristics in the TT plasma discharges, especially on the presence of the 8.8 MeV peak, a consequence of channel (2) of the TT reaction. The possibility to use an optimized set of activation materials in order to target the measurement of the 8.8 MeV peak is studied. The lower limit of detection for the channel (2) ratio within the TT reaction is estimated and the influence of DT source neutrons, which are a consequence of deuterium traces in the plasma, is investigated

Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons

Modelling of the neutron production in a mixed beam DT neutron generator

Compact DT neutron generators based on accelerators are often built on the principle of a mixed beam operation, meaning that deuterium (D) and tritium (T) are both present in the ion beam and in the target. Moreover, the beam consists of a mixture of ions and ionized molecules (D, T ions, and ionized D-D, T-T and D-T molecules) so the relevant source components come from T(d, n), D(t, n), D(d, n) and T(t, 2n) reactions at different ion energies. The method for assessing the relative amplitudes of different source components (DD, DT, TT) is presented. The assessment relies on the measurement of the neutron spectrum of different DT components (T(d, n) and D(t, n) at different energies) using a high resolution neutron spectrometer, e.g. a diamond detector, fusion reaction cross-sections, and simulations of neutron generation in the target. Through this process a complete description of the neutron source properties of the mixed beam neutron generator can be made and a neutron source description card, in a format suitable for Monte Carlo code MCNP, produced