Cruciform specimen’s analysis and experiments in ultrasonic fatigue testing

The reliability of any given structure or machine subjected to dynamic loads is mainly dependent on the detailed fatigue study of the applied materials. As the demand for higher life cycles with more complex stress applications increases, so does the necessity for new and more complex fatigue testing methods. Since it was proven before that a fatigue limit should no longer be considered, ultrasonic fatigue tests were developed for the study of the life beyond that point. This is now known as the Very High Cycle Fatigue (VHCF) regime. In these tests, specimens are subjected to stress cycles in frequencies as high as 20 kHz. Most ultrasonic fatigue tests apply uniaxial stresses, but it is important to be able to apply complex multiaxial loading since most components are subjected to a complex stress state when under cyclic loading. In this work, cruciform specimens are used in an ultrasonic fatigue machine. Two different geometries, capable of inducing in-plane biaxial stress combinations (in-phase and out-of-phase) in the VHCF range, are studied. The geometries are subjected to both numerical analysis and experimental testing to understand if they are working as intended. For those who do so, a test until failure was carried through to observe and evaluate the fracture surface

A comprehensive Monte Carlo study of CT dose metrics proposed by the AAPM Reports 111 and 200

Purpose A Monte Carlo (MC) modeling of single axial and helical CT scan modes has been developed to compute single and accumulated dose distributions. The radiation emission characteristics of an MDCT scanner has been modeled and used to evaluate the dose deposition in infinitely long head and body PMMA phantoms. The simulated accumulated dose distributions determined the approach to equilibrium function, H(L). From these urn:x-wiley:00942405:media:mp15306:mp15306-math-0001 curves, dose-related information was calculated for different head and body clinical protocols. Methods The PENELOPE/penEasy package has been used to model the single axial and helical procedures and the radiation transport of photons and electrons in the phantoms. The bowtie filters, heel effect, focal-spot angle, and fan-beam geometry were incorporated. Head and body protocols with different pitch values were modeled for x-ray spectra corresponding to 80, 100, 120, and 140 kV. The analytical formulation for the single dose distributions and experimental measurements of single and accumulated dose distributions were employed to validate the MC results. The experimental dose distributions were measured with OSLDs and a thimble ion chamber inserted into PMMA phantoms. Also, the experimental values of the urn:x-wiley:00942405:media:mp15306:mp15306-math-0002 along the center and peripheral axes of the CTDI phantom served to calibrate the simulated single and accumulated dose distributions. Results The match of the simulated dose distributions with the reference data supports the correct modeling of the heel effect and the radiation transport in the phantom material reflected in the tails of the dose distributions. The validation of the x-ray source model was done comparing the CTDI ratios between simulated, measured and CTDosimetry data. The average difference of these ratios for head and body protocols between the simulated and measured data was in the range of 13-17% and between simulated and CTDosimetry data varied 10-13%. The distributions of simulated doses and those measured with the thimble ion chamber are compatible within 3%. In this study, it was demonstrated that the efficiencies of the urn:x-wiley:00942405:media:mp15306:mp15306-math-0003 measurements in head phantoms with nT = 20 mm and 120 kV are 80.6% and 87.8% at central and peripheral axes, respectively. In the body phantoms with urn:x-wiley:00942405:media:mp15306:mp15306-math-0004= 40 mm and 120 kV, the efficiencies are 56.5% and 86.2% at central and peripheral axes, respectively. In general terms, the clinical parameters such as pitch, beam intensity, and voltage affect the Deq values with the increase of the pitch decreasing the Deq and the beam intensity and the voltage increasing its value. The H(L) function does not change with the pitch values, but depends on the phantom axis (central or peripheral). Conclusions The computation of the pitch-equilibrium dose product, urn:x-wiley:00942405:media:mp15306:mp15306-math-0005, evidenced the limitations of the urn:x-wiley:00942405:media:mp15306:mp15306-math-0006 method to determine the dose delivered by a CT scanner. Therefore, quantities derived from the urn:x-wiley:00942405:media:mp15306:mp15306-math-0007 propagate this limitation. The developed MC model shows excellent compatibility with both measurements and literature quantities defined by AAPM Reports 111 and 200. These results demonstrate the robustness and versatility of the proposed modeling method

Can a restocking event with European (glass) eels cause early changes in local biological communities and its ecological status?

In an attempt to assist the recovery of the panmictic population of the European eel, declining since the late 1980s, the restocking of areas with low or no natural recruitment has been one of the measures adopted to reverse this trend. However, the main focus in several monitoring programmes for these actions, has been in the best interest of its viability and cost/benefit relationships and, for that, the condition of the released stocks has been the main concern. Yet, so far, no studies have assessed the potential ecological impacts that restocking might have on other biological communities. This pioneer pilot study aimed to evaluate the early ecological impact of a restocking event on other biological communities, considering inter-specific competition (other fish species) and feeding impact (macroinvertebrates).The reference condition of the biological communities of an inland tributary of the Mondego river, the River Ceira, was determined in three sites inaccessible to the natural recruitment of eels, followed by a post-stocking assessment. The results showed no significant changes in the fish assemblages in restocked areas, contrary to the macroinvertebrate community. However, the ecological status for the macroinvertebrate community showed no deleterious effects, with the results suggesting exactly the opposite. This may be related to the low density of the restocked eels and factors influencing the local trophic web. This study confirms the suitability of the habitat for restocking with glass eels, during its early stages, without disrupting the local ecological status, using densities close to those of natural recruitment

Quinze anos de monitorização das comunidades biológicas do estuário do Tejo no âmbito da construção e funcionamento das ETARs do Portinho da Costa e da Mutela (Concelho de Almada): Experiência adquirida e ensinamentos para futuros casos semelhantes.

Desde 2001 que a Câmara Municipal de Almada tem vindo a promover, em colaboração com o MARE, a monitorização ambiental das regiões estuarinas sob influência das ETARs do Portinho da Costa e da Mutela, que vieram substituir efluentes não tratados emitidos sensivelmente nas mesmas regiões. O objetivo deste programa de monitorização consiste em avaliar as principais alterações ocorridas (na maioria dos casos positivas) nos ecossistemas estuarinos dos vários locais, após a entrada em funcionamento de ambas as infraestruturas. Estes 15 anos de estudos das comunidades bentónicas e de peixes locais têm permitido identificar variações nos padrões espácio-temporais destes compartimentos biológicos e identificar quais dessas evoluções podem ser presumivelmente relacionáveis com o funcionamento das infraestruturas e quais derivam provavelmente de flutuações naturais. Nesta comunicação são enunciados os pressupostos do estudo, descritos os delineamentos experimentais e metodologias de tratamento dos dados adotados, apresentados os principais resultados obtidos e discutidas as grandes dificuldades sentidas para cumprir os objetivos estabelecidos. Este conjunto de elementos será analisado numa perspetiva de como a experiência adquirida pode ser útil, no futuro, para casos semelhantes, sobretudo numa ótica da correta identificação dos verdadeiros efeitos infraestruturais e de despiste da influência de outros fatores concorrentes

Fine-scale behaviour of the Lusitanian toadfish assessed in situ with the AccelTag

Three-axis acceleration sensor acoustic transmitters (AccelTag) programmed to identify specific acceleration patterns associated with particular behaviours (e.g., burrowing, attack) were used to study some aspects of the ecology of the Lusitanian toadfish Halobatrachus didactylus (Bloch & Schneider 1801). The AccelTag combines the features of archival tags (records acceleration in all three directions measuring also roll-independent pitch/tilt angle and roll around the fish’s axis) and acoustic transmitters. Therefore, this tag can autonomously identify and record specific signatures (i.e., behaviour patterns) of different movements transmitting autonomously and periodically the data to an acoustic biotelemetry receiver. Lusitanian toadfish is a subtropical marine teleost confined to estuaries in its northern limit of distribution due to thermal constraints. During 2010 (August and October), 24 toadfish were captured, tagged with the AccelTag and released in the Mira estuary, SW coast of Portugal, where an array of underwater automatic acoustic biotelemetry receivers was deployed

PREVALÊNCIA DE INFECÇÃO URINÁRIA E DE Actinomyces suis EM PORCAS GESTANTES E SUA CORRELAÇÃO COM ALGUNS PARÂMETROS FÍSICOS E QUÍMICOS DA URINA

O presente trabalho teve como objetivo determinar a prevalência de infecção urinária e da bactéria Actinomyces suis na urina de 1745 porcas gestantes da região Sul do Brasil e correlacionar essa prevalência com parâmetros físicos e químicos da urina. A prevalência de infecção urinária e de A. suis foi de 28,31% e 20,63%, respectivamente. Observou-se correlação negativa entre infecção urinária e A. suis, ou seja, as porcas que apresentaram infecção urinária tinham menor prevalência de A. suis (13,67%) do que as que não a apresentaram (23,12%). Da mesma forma, as porcas portadoras de A. suis, tinham menor prevalência de infecção urinária (17,43%) do que as não portadoras (28,62%). Apenas 3,60% das porcas examinadas eram positivas para infecção urinária e A. suis simultaneamente. A cor predominante da urina foi a amarelo claro, tanto para as porcas portadoras ou não portadoras de infecção urinária ou de A. suis. Constatou-se a presença de turbidez em 83,15% das amostras, sendo que em 96,18% das amostras turvas observou-se a presença de cristais. Finalmente, a cor, aspecto, densidade, pH e presença de cristais, foram considerados como parâmetros sem valor para o diagnóstico presuntivo de infecção urinária em porcas gestantes. Prevalence of urinary tract infections and of Actinomyces suis in urine from pregnant sows. Correlation with some urines physical and chemical parameters Abstract A survey has been carried out in urine samples from 1745 pregnant sows from Southern Brazil, in regard to the prevalence of urinary infections and of Actinomyces suis and its correlation with some of the urine physical and chemical parameters. Prevalence of urinary infections was of 28.31% and that of A. suis, 20.63%. However, a negative correlation has been found between the incidence of urinary infection and the presence of A. suis, the prevalence of the latter being lower in sows which are positive for urinary infections (13.67%) than in those without urinary infection (23.12%). At the same time, sows positive for A. suis display a lesser number of urinary infection (17.43%) than those negative for the bacteria (28.62%). Only in 3.60% of the sows, urinary infection and A. suis occurred simultaneously. Due to the presence of crystals, turbidity was frequently observed in sows urine (83.15%). Crystals were present in 96.18% of sows turbid urine samples. Furthermore, color, turbidity, density, pH and the presence of crystals were not considered of value for the presumptive diagnosis of urinary tract infections in pregnant sows

Movements of hatchery-reared dusky groupers released in a Northeast Atlantic Coastal Marine Protected Area.

No-take areas are key instruments to promote the effectiveness of Marine Protected Areas (MPAs), particularly concerning the protection of endangered species such as the dusky grouper (Epinephelus marginatus). However, despite the establishment of no-take areas and the prohibition of catching this species in a southwestern Portuguese MPA (SACVMP—‘Sudoeste Alentejano’ and ‘Costa Vicentina’ Marine Park) since 2011, there is still no evidence of population recovery. By using acoustic biotelemetry, this work aimed to evaluate the feasibility of restocking hatchery-reared adult dusky groupers in two no-take areas within the SACVMP. In 2019 and 2021, thirty groupers were tagged with acoustic transmitters and the site attachment and movements of the groupers were assessed in the releasing sites (no-take areas). None of the tagged fish settled down in either of the areas, leaving the no-take areas mainly at dusk and night. Some individuals displayed extended movements of more than a hundred kilometers along the Portuguese coast which was rarely reported for this species. At least in some coastal stretches, those movements were performed close to the shore, which may evidence the importance of coastal MPAs to protect and promote the connectivity of species more associated with rocky reef habitats. Following studies should focus on the conditions that promote site attachment and fidelity by hatchery-reared dusky groupers so that future large-scale restocking programs can be successful in MPAs with appropriate habitats

The caregiver perspective: an assistive AAL platform

The Ambient Assisted Living area has spawned several projects that aim to help the user on his/her daily activities. The AAL4ALL (ambient assisted living for all) project aims to develop a unified ecosystem using fully compatible devices and services. The UserAccess platform is part of the AAL4ALL and has as a goal to provide assistance to a type of actor that is commonly forgotten in the Ambient Assisted Living area, the caregiver. This paper presents the archi-tecture, implementation, and interfaces, along with a brief analysis of caregiver’s needs and work related issues.Project "AAL4ALL", co-financed by the European Community Fund FEDER, through COMPETE - Programa Operacional Factores de Competitividade (POFC). Foundation for Science and Technology (FCT), Lisbon, Portugal, through Project PEst-C/CTM/LA0025/2013 and the project PEst-OE/EEI/UI0752/2014. Project CAMCoF - Context-aware Multimodal Communication Framework funded by ERDF -European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-028980