Mechanical properties of fly ash geopolymers containing steelmaking ladle slag

The effect of adding steelmaking ladle slag to fly ash based geopolymers has been studied. For that, flexural and compression strengths were evaluated at 7 and 28 days after curing. It can be concluded that the increase in fly ash content has a relevant effect on the various mechanical properties.W2V, SA, Geodesigninfo:eu-repo/semantics/publishedVersio

Fracture behavior in geopolymer mixtures including fly ash and various industrial waste

The fracture resistance behavior of fly ash based geopolymer mixtures incorporating different types of industrial wastes has been investigated. Therefore, 4 different geopolymer mixtures were analyzed, with the intent to retrieve information about their Initial Flexural Stiffness (Ri), and Ultimate Load (Pu). A result analysis revealed that one type of mixture was considerably superior to the rest in terms of Initial Flexural Stiffness and Ultimate Load.W2V, SA, Geodesigninfo:eu-repo/semantics/publishedVersio

Tribologial behavior of geopolymer mixtures including fly ash and various industrial wastes

The tribological behavior of fly ash based geopolymer mixtures incorporating different types of industrial waste has been investigated. Therefore, 5 different geopolymer mixtures were analyzed, with the intent to retrieve information about their Coefficient of Friction (COF) and degradation by weight loss, as a result of direct contact with a stainless steel pin. A result analysis revealed varying results across the different mixture.Projeto Geodesigninfo:eu-repo/semantics/publishedVersio

Low-latitude equinoctial spread-F occurrence at different longitude sectors under low solar activity

We present the results of a comparative study of spread-F signatures over five low-latitude sites: Chiangmai (CGM; 18.8° N, 98.9° E, mag. Lat. 8.8° N), Thailand; Tanjungsari (TNJ; 6.9° S, 107.6° E, mag. Lat. 16.9° S), Indonesia; Palmas (PAL; 10.2° S, 311.8° E, mag. Lat. 0.9° S) and São José Dos Campos (SJC; 23.2° S, 314.1° E, mag. Lat. 14.0° S), Brazil; and Tucumán (TUC; 26.9° S, 294.6° E, mag. Lat. 16.8° S), Argentina. The investigation was based on simultaneous ionograms recorded by an FMCW (frequency-modulated continuous-wave) at CGM, an IPS-71 (digital ionosonde from KEL aerospace) at TNJ, a CADI (Canadian Advanced Digital Ionosonde) at PAL and SJC, and an AIS-INGV (Advanced Ionospheric Sounder – Istituto Nazionale di Geofisica e Vulcanologia) at TUC, during the equinoctial periods March–April (R12 = 2.0 and R12 = 2.2) and September–October (R12 = 6.1 and R12 = 7.0) 2009, for very low solar activity. Spread-F signatures were categorized into two types: the range spread-F (RSF) and the frequency spread-F (FSF). The study confirms that the dynamics and the physical processes responsible for these phenomena are actually complicated. In fact, the features that arise from the investigation are different, depending on both the longitude sector and on the hemisphere. For instance, TUC, under the southern crest of the ionospheric equatorial ionization anomaly (EIA), shows a predominance of RSF signatures, while both SJC, under the southern crest of EIA but in a different longitude sector, and CGM, under the northern crest of EIA, show a predominance of FSF signatures. Moreover, the spread-F occurrence over the longitude sector that includes CGM and TNJ is significantly lower than the spread-F occurrence over the longitude sector of PAL, SJC, and TUC.Fil: Pezzopane, M.. Istituto Nazionale Di Geofisica E Vulcanologia; Italia;Fil: Zuccheretti, E.. Istituto Nazionale Di Geofisica E Vulcanologia; Italia;Fil: Abadi, P.. Indonesian National Institute of Aeronautics and Space. Space Science Center. Division of Ionosphere and Telecommunication; Indonesia;Fil: de Abreu, A. J.. Universidade do Vale do Paraíba; Brazil;Fil: de Jesus, R.. Universidade do Vale do Paraíba; Brazil;Fil: Fagundes, P. R.. Universidade do Vale do Paraíba; Brazil;Fil: Supnithi, P.. King Mongkut’s Institute of Technology Ladkrabang . Faculty of Engineering; Tailandia;Fil: Rungraengwajiake, S.. King Mongkut’s Institute of Technology Ladkrabang . Faculty of Engineering; Tailandia;Fil: Nagatsuma, T.. National Institute of Information and Communications Technology. Space Weather and Environment Informatics Laboratory; Japón;Fil: Tsugawa, T.. National Institute of Information and Communications Technology. Space Weather and Environment Informatics Laboratory; Japón;Fil: Cabrera, Miguel Angel. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina; Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación de Atmósfera Superior y Radiopropagación; Argentina;Fil: Ezquer, Rodolfo Gerardo. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación de Atmósfera Superior y Radiopropagación; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina

Evaluation of the maize (Zea mays L.) diversity on the Archipelago of Madeira

The variability of 43 open-pollinated populations of maize (Zea mays L.), representing a wide range of ecological conditions on the Archipelago of Madeira, was evaluated based on the morphological and reproductive traits. Individual data of 41 traits related to earliness, plant and tassel structure and the shape of the ear and grain were analysed using multivariate analysis. The populations belonging to two major maize varieties were grouped into four groups by their degree of dissimilarity, based on discriminant analysis. The dissimilarity of these groups was confirmed by the values of the Tukey test. The racial rank of these groups was proposed and a brief description of the maize landraces was presented. This work represents the first morphological characterization and analysis of diversity of maize germplasm for the Archipelago of Madeira where the traditional agricultural practices are still keeping this Portuguese region free from corn hybrids. The description of the Madeiran corn landraces allows us to preserve the existing corn biodiversity and could be used for their registration as conservation landraces or for conservation and breeding proposes worldwide.Portuguese Foundation for the Science and Technology (FCT, Fundac¸a˜o para a Cieˆncia e Tecnologia) has sponsored this work, through the Centre of Macaronesian Studies (CEM) and the project POCTI no35003/AGR/2001. The Authors are grateful to the Madeiran farmers who assisted with collection of maize samples.info:eu-repo/semantics/publishedVersio

Identification of aluminum resistant genotypes among Madeiran regional wheats

Forty-eight genotypes representing wheat diversity from the Island of Madeira were screened for resistance to aluminum (Al) in nutrient solution. Seeds of wheat used in the experiments were obtained from local farmers. The soil pH and content of ionic Al of plots cultivated with wheat were analyzed. The pH of topsoils varied between 3.83 and 6.59. The amount of ionic Al in soil samples varied between 0.38 and 1.36 cmol Al3 + per kg of soil and was positively correlated with the altitude of a plot. Eriochrome cyanine staining was used to evaluate the effect of Al ions on the root elongation. Seventy-two hour exposure of 3-day-old seedlings to 100 and 200 mM Al in nutrient solution revealed a high number of Al resistant genotypes among wheat germplasm. After withdrawal of Al stress, survival and root regrowth was observed in 28 and 23 genotypes screened at 100 and 200 mM Al in nutrient solution, respectively. Enhanced resistance to Al among Madeiran genotypes was associated with the amount of ionic Al in the soils. Complexity and various patterns of responses of tested cultivars to Al stress may suggest that Madeiran germplasm could be a valuable source of genes controlling Al resistance for conventional breeding programs and for studies of molecular bases of mechanisms of Al resistance.Portuguese Foundation for the Science and Technology (FCT, Fundac¸o para a Cieˆncia e Tecnologia) has sponsored this work, through the Centre of Biological and Geological Sciences (C.C.B.G.) and the project POCTI/no. 33005/AGR/1999. The authors are also grateful to the Madeiran Centre of Science and Technology (CITMA) for financial support. Acknowledgements are due to Mr. Roge´rio Correia and Juan Silva for the technical assistance in conducting the laboratory and fieldwork and to Dr. Andrzej Aniol for valuable advice during preparation of this manuscript.info:eu-repo/semantics/publishedVersio

Disc galaxies are still settling: The discovery of the smallest nuclear discs and their young stellar bars

When galactic discs settle and become massive enough, they are able to form stellar bars. These non-axisymmetric structures induce shocks in the gas, causing it to flow to the centre where nuclear structures, such as nuclear discs and rings, are formed. Previous theoretical and observational studies have hinted at the co-evolution of bars and nuclear discs, suggesting that nuclear discs grow "inside-out", thereby proposing that smaller discs live in younger bars. Nevertheless, it remains unclear how the bar and the nuclear structures form and evolve with time. The smallest nuclear discs discovered to date tend to be larger than $\sim200~\rm{pc}$, even though some theoretical studies find that when nuclear discs form they can be much smaller. Using MUSE archival data, we report for the first time two extragalactic nuclear discs with radius sizes below $100~\rm{pc}$. Additionally, our estimations reveal the youngest bars found to date. We estimate that the bars in these galaxies formed $4.50^{+1.60}_{-1.10}\rm{(sys)}^{+1.00}_{-0.75}\rm{(stat)}$ and $0.7^{+2.60}\rm{(sys)}^{+0.05}_{-0.05}\rm{(stat)}~\rm{Gyr}$ ago, for NGC\,289 and NGC\,1566, respectively. This suggests that at least some disc galaxies in the Local Universe may still be dynamically settling. By adding these results to previous findings in the literature, we retrieve a stronger correlation between nuclear disc size and bar length and we derive a tentative exponential growth scenario for nuclear discs.Comment: Accepted in A&A (in press), 13 pages, 5 figures, 2 tabel

Impacts of Bar-driven Shear and Shocks on Star Formation

Bars drive gas inflow. As the gas flows inward, shocks and shear occur along the bar dust lanes. Such shocks and shear can affect the star formation (SF) and change the gas properties. For four barred galaxies, we present Hα velocity gradient maps that highlight bar-driven shocks and shear using data from the PHANGS-MUSE and PHANGS-ALMA surveys, which allow us to study bar kinematics in unprecedented detail. Velocity gradients are enhanced along the bar dust lanes, where shocks and shear are shown to occur in numerical simulations. Velocity gradient maps also efficiently pick up H ii regions that are expanding or moving relative to the surroundings. We put pseudo-slits on the regions where velocity gradients are enhanced and find that Hα and CO velocities jump up to ∼170 km s−1, even after removing the effects of circular motions due to the galaxy rotation. Enhanced velocity gradients either coincide with the peak of CO intensity along the bar dust lanes or are slightly offset from CO intensity peaks, depending on the objects. Using the Baldwin–Philips–Terlevich BPT diagnostic, we identify the source of ionization on each spaxel and find that SF is inhibited in the high-velocity gradient regions of the bar, and the majority of those regions are classified as a low-ionization nuclear emission-line region (LINER) or composite. This implies that SF is inhibited where bar-driven shear and shocks are strong. Our results are consistent with the results from the numerical simulations that show SF is inhibited in the bar where the shear force is strong