Prediction of the mechanical properties of granites by ultrasonic pulse velocity and Schmidt hammer hardness

The present work deals with the use of simple and economical non destructive techniques, ultrasonic pulse velocity and Schmidt hammer to predict the strength and elastic properties of granitic stones that are characteristic in ancient masonry constructions. Good correlations between NDTs and strength and modulus of elasticity were found, which indicate them as appropriate techniques for estimating the mechanical properties

Experimental properties of granites

In the present work, a study of the tensile mechanical behavior of a set of twelve selected granite lithotypes is carried out. Some petrographic aspects such as grain size and presence of planar anisotropy explain the variation on the parameters that characterize the tensile behavior, like the strength and fracture energy. Other factors that influence the tensile mechanical behavior, such as weathering degree and physical properties like porosity and density, are also analyzed. Statistical correlations between the ultrasonic pulse velocity and the mechanical and physical properties are proposed

Analysis of weathering and internal texture on the engineering properties of granites

The research significance of the present paper concerns the need of knowing the mechanical properties of stone existing in the ancient constructions, when a suitable methodology for their rehabilitation or strengthening is followed. The rehabilitation of ancient constructions, mainly the ones pertaining to the architectural heritage is a demand of modern societies. The deep knowledge of mechanical and fracture properties of the stone is also an important advantage, when structural analysis is needed for the evaluation of the safety conditions of ancient constructions. Thus, this paper aims at providing large information about the influence of factors such as weathering state and planar anisotropy on the engineering properties of Portuguese granites. It was found that both weathering and internal structure play a major role on the mechanical tensile and compressive behavior of granites. Besides, the non-destructive evaluation reveal as possible technique to predict the weathering and anisotropy of granites

Alimentación del delfín costero, Sotalia guianensis (Cetacea: Delphinidae), en la bahía Norte al sur de Brasil

The stomach contents of 18 Guiana dolphins stranded or accidentally caught by fishing around Norte Bay of Santa Catarina Island between 1990 and 2006 were examined. The small population of Guiana dolphins studied showed a varied diet, and prey was caught disproportionately. The stomach contents of these dolphins consisted of 448 prey remains coming from 18 species and 10 families. Their diet primarily consisted of fish, but also shrimp and squid. The most important species were cutlass fish (Trichiurus lepturus) and white mouth croaker (Micropogonias furnieri), which together comprised 75% of the total biomass. Although prey size ranged widely from 1.4 to 92.8 cm, a prevalence of prey smaller than 20 cm was observed. There was a predominance of prey living in moderate or large schools. The prey also had a wide vertical distribution in the water column. Our results support the opportunistic feeding habit of the Guiana dolphin, since its diverse diet was clearly guided by the availability and accessibility of resources in its habitat.Se estudiaron los contenidos del estómago de 18 delfines costeros capturados accidentalmente por redes de pesca o encontrados encallados alrededor de la bahía Norte de la isla de Santa Catarina entre 1990 y 2006. La composición de la dieta de los delfines fue variada, pero con predominio de algunas presas. Los contenidos estomacales consistieron en 448 restos de presas, que correspondieron a 18 especies y 10 familias. La mayoría de las presas fueron principalmente peces, pero también estuvieron representados cefalópodos y crustáceos. Las especies más importantes fueron el pez sable (Trichiurus lepturus) y la corvina rubia (Micropogonias furnieri), que juntos representaron un 75% de la biomasa total. Aunque el tamaño medio de las presas varió entre 1.4 y 92.8 cm, hubo una prevalencia de presas más pequeñas de 20 cm. Se observó un predominio de presas que viven agregadas en cardúmenes de mediano a gran tamaño y con amplia distribución vertical en la columna de agua. Nuestros resultados apoyan el hábito alimenticio oportunista de Sotalia guianensis, ya que su variada dieta está claramente guiada por la disponibilidad y accesibilidad de los recursos en su hábitat

The Cs-137 radiological accident in Goiânia, Brazil: Conditions and results of the airborne radiometric survey

This paper describes the details of the aeroradiometric operations, the radiation detection system used and discusses the results. The low-altitude survey was carried out over Goiânia a few days after information of the accident was received by the national competent authority, the Brazilian Nuclear Energy Commission (CNEN). Given the little information at the time of the accident and the urgency to respond to the local and federal authorities, an aerial radiometric survey was proposed to evaluate the extent of the contamination and dispersion of the radioactive powder. The city's entire urban area and nearby dwellings centers, plus the two creeks crossing the city were surveyed in two days. The survey found only one additional contamination point 2.8 x 10-4 C/kg/h (1.1 R/h) that had not yet been identified by ground survey crews. Furthermore, no contamination was found along the margins of the Capim Puba Creek and Meia Ponte rivers which could be contaminated due to rainwater common at that time of the year. Detection tests conducted at different altitudes over the main contamination area showed that the Cs-137 gamma radiation could be detected even at altitudes of 350m above the ground. This was much higher than the 40 m - 70 m decided for the overflights. The survey demonstrated that the contamination was restricted to a few locations in the neighborhood of the metal scrap place where the source shield was broken. These locations were under the control of CNEN radiological emergency response personnel. Such a finding was an important indicator to calm down the population and the government authorities. This allowed concentrating attention on the remediation of the known points of high gamma activity

Reproducing type II white-light solar flare observations with electron and proton beam simulations

We investigate the cause of the suppressed Balmer series and the origin of the white-light continuum emission in the X1.0 class solar flare on 2014 June 11. We use radiative hydrodynamic simulations to model the response of the flaring atmosphere to both electron and proton beams, which are energetically constrained using Ramaty High Energy Solar Spectroscopic Imager and Fermi observations. A comparison of synthetic spectra with the observations allows us to narrow the range of beam fluxes and low energy cutoff that may be applicable to this event. We conclude that the electron and proton beams that can reproduce the observed spectral features are those that have relatively low fluxes and high values for the low energy cutoff. While electron beams shift the upper chromosphere and transition region to greater geometrical heights, proton beams with a similar flux leave these areas of the atmosphere relatively undisturbed. It is easier for proton beams to penetrate to the deeper layers and not deposit their energy in the upper chromosphere where the Balmer lines are formed. The relatively weak particle beams that are applicable to this flare do not cause a significant shift of the τ = 1 surface and the observed excess WL emission is optically thin

Gulls in Porto Coastline as Reservoirs for Salmonella spp.: Findings from 2008 and 2023

(This article belongs to the Special Issue Water Microorganisms Associated with Human Health)Gulls act as intermediaries in the exchange of microorganisms between the environment and human settlements, including Salmonella spp. This study assessed the antimicrobial resistance and molecular profiles of Salmonella spp. isolates obtained from fecal samples of gulls in the city of Porto, Portugal, in 2008 and 2023 and from water samples in 2023. Antimicrobial susceptibility profiling revealed an improvement in the prevalence (71% to 17%) and antimicrobial resistance between the two collection dates. Two isolate collections from both 2008 and 2023 underwent serotyping and whole-genome sequencing, revealing genotypic changes, including an increased frequency in the monophasic variant of S. Typhimurium. qacE was identified in 2008 and 2023 in both water and fecal samples, with most isolates exhibiting an MDR profile. The most frequently observed plasmid types were IncF in 2008 (23%), while IncQ1 predominated in 2023 (43%). Findings suggest that Salmonella spp. circulate between humans, animals, and the environment. However, the genetic heterogeneity among the isolates from the gulls' feces and the surface water may indicate a complex ecological and evolutionary dynamic shaped by changing conditions. The observed improvements are likely due to measures to reduce biological contamination and antimicrobial resistance. Nevertheless, additional strategies must be implemented to reduce the public health risk modeled by the dissemination of pathogens by gulls.Funding: WGS was supported by funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No 773830: One Health European Joint Programme, as part of the DiSCoVeR project (Discovering the sources of Salmonella, Campylobacter, VTEC, and Antimicrobial Resistance).info:eu-repo/semantics/publishedVersio

Dolphin population specialized in foraging with artisanal fishers requires zero-bycatch management to persist

This study was conducted as part of a PhD thesis in the Graduate Programme in Ecology at the Federal University of Santa Catarina, with funding provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – 407190/2012-0) and Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina (FAPESC – TR2012000295). This study is also part of the SELA Long-Term Ecological Research Programme (PELD CNPq – 445301/2020-1). C.B. received a doctoral scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); P.C.S.L. received a research grant from CNPq (305573/2013-6); F.G.D.J. received a research grant from CNPq (308867/2019-0).1. The small population paradigm assumes that populations with low numbers of individuals intrinsically have a high probability of extinction. The small population of Lahille's bottlenose dolphins Tursiops truncatus gephyreus that specializes in foraging with artisanal fishers in Laguna, southern Brazil, faces human pressures including bycatch in fishing gear. The viability of this population was modelled over 30 and 100 years under different levels of bycatch, including the current scenario of two bycatches every year, two scenarios with higher incidence of bycatches and three management scenarios. The sensitivity of predicted growth rates to fixed-proportion and observed-variation changes in life history parameters was explored. 2. The current scenario predicted a declining population (r = -0.014; λ = 0.986) with a high probability of extinction in the long term (PE = 0.71). A small increase in bycatches would result in a marked increase in the probability of extinction. Management scenarios seem promising, but only the zero-bycatch management scenario would make the difference between a declining and an increasing population. 3. As expected for slow-growing species, population growth rate was most sensitive to proportional changes in adult female and juvenile survival. However, considering observed variation in vital rates, population dynamics were most influenced by variation in reproductive rates. 4. To determine the highest priority for management action, another simulation was made of how additional threat scenarios of recognized human activities (i.e. bycatch influencing adult survival and increased underwater noise or pollution influencing calf survival) would affect population dynamics. Population growth rate was very sensitive to changes in adult bycatch (especially females), as expected, and only subtly sensitive to a reduction in calf survival. 5. The current level of bycatch is unsustainable. Bycatch needs to be eliminated to maximize the probability of long-term persistence of this dolphin population. However, this population's persistence could be threatened by natural variation in reproductive rates.PostprintPeer reviewe