Use of acoustic energy in the processing of molten aluminium alloys

During the last years aluminium alloys have been gaining increased acceptance as structural materials in the automotive and aeronautical industries, mainly due to their light weight, good formability and corrosion resistance. However, improvement of mechanical properties is a constant in research activities, either by the development of new alloys or by microstructure manipulation. This presentation focuses a novel effective dynamic methodology to perform microstructural refinement / modification and degassing of light alloys, namely aluminium alloys, by applying acoustic energy to the melts. High intensity acoustic energy significantly improves the microstructure, therefore the mechanical properties of those alloys, avoiding the use of traditional chemically based degassing and refining techniques which are less effective and present significant environmental impact. Ultrasonic (US) vibration has proven to be extremely effective in degassing, controlling columnar dendritic structure, reducing the size of equiaxed grains and, under some conditions, producing globular grains and modifying the eutectic silicon cells in Al-Si alloys. The mechanisms of US processing of aluminium melts are discussed and experimental results on this field are presented.Fundação para a Ciência e Tecnologia (FCT

Project Proof: Internet Enabled Process Reengineering at J.D. Edwards & Company

J.D. Edwards is a provider of the new generation of ERP and collaborative commerce solutions. This case study describes the challenges faced internally by the company to upgrade to the latest enterprise software it would sell to the world. Dubbed Project PROOF, the project started in June 2001 and was completed in November 2002. The perspectives of the CIO, the program manager, and other key personnel are presented. The case study highlights the issues that arise in an enterprise software implementation project. In addition, the case touches upon issues of project management, process redesign, and marketing. The case study uses a multimedia format to add richness and detail. Although J.D. Edwards was acquired in 2003, the issues discussed are relevant to current business practices

Thermal instability in ionized plasma

We study magnetothermal instability in the ionized plasmas including the effects of Ohmic, ambipolar and Hall diffusion. Magnetic field in the single fluid approximation does not allow transverse thermal condensations, however, non-ideal effects highly diminish the stabilizing role of the magnetic field in thermally unstable plasmas. Therefore, enhanced growth rate of thermal condensation modes in the presence of the diffusion mechanisms speed up the rate of structure formation.Comment: Accepted for publication in Astrophysics & Space Scienc

Higher Order Evaluation of the Critical Temperature for Interacting Homogeneous Dilute Bose Gases

We use the nonperturbative linear \delta expansion method to evaluate analytically the coefficients c_1 and c_2^{\prime \prime} which appear in the expansion for the transition temperature for a dilute, homogeneous, three dimensional Bose gas given by T_c= T_0 \{1 + c_1 a n^{1/3} + [ c_2^{\prime} \ln(a n^{1/3}) +c_2^{\prime \prime} ] a^2 n^{2/3} + {\cal O} (a^3 n)\}, where T_0 is the result for an ideal gas, a is the s-wave scattering length and n is the number density. In a previous work the same method has been used to evaluate c_1 to order-\delta^2 with the result c_1= 3.06. Here, we push the calculation to the next two orders obtaining c_1=2.45 at order-\delta^3 and c_1=1.48 at order-\delta^4. Analysing the topology of the graphs involved we discuss how our results relate to other nonperturbative analytical methods such as the self-consistent resummation and the 1/N approximations. At the same orders we obtain c_2^{\prime\prime}=101.4, c_2^{\prime \prime}=98.2 and c_2^{\prime \prime}=82.9. Our analytical results seem to support the recent Monte Carlo estimates c_1=1.32 \pm 0.02 and c_2^{\prime \prime}= 75.7 \pm 0.4.Comment: 29 pages, 3 eps figures. Minor changes, one reference added. Version in press Physical Review A (2002

A step forward

Funding: Authors gratefully acknowledge Fundação para a Ciência e a Tecnologia (FCT) through projects UIDB/00645/2020, UIDB/04138/2020, PTDC/MED-QUI/31721/2017, UIDP/04138/2020 and Lusófona University, ULHT. Authors are also thankful to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020, UIDB/50017/2020), through national funds.Anaplastic thyroid carcinoma (ATC) is a very rare subtype of thyroid carcinoma and one of the most lethal malignancies. Poor prognosis is mainly associated with its undifferentiated nature, inoperability, and failing to respond to the typically used therapies for thyroid cancer. Photothermal Therapy (PTT) entails using light to increase tissues’ temperature, leading to hyperthermia-mediated cell death. Tumours are more susceptible to heat as they are unable to dissipate it. By using functionalized gold nanoparticles (AuNPs) that transform light energy into heat, it is possible to target the heat to the tumour. This study aims to formulate ATC-targeted AuNPs able to convert near-infrared light into heat, for PTT of ATC. Different AuNPs were synthetized and coated. Size, morphology, and surface plasmon resonances band were determined. The optimized coated-AuNPs were then functionalized with ligands to assess ATC’s specificity. Safety, efficacy, and selectivity were assessed in vitro. The formulations were deemed safe when not irradiated (>70% cell viability) and selective for ATC. However, when irradiated, holo-transferrin-AuNPs were the most cytotoxic (22% of cell viability). The biodistribution and safety of this formulation was assessed in vivo. Overall, this novel formulation appears to be a highly promising approach to evaluate in a very near future.publishersversionpublishe

The effect of the dynamical state of clusters on gas expulsion and infant mortality

The star formation efficiency (SFE) of a star cluster is thought to be the critical factor in determining if the cluster can survive for a significant (>50 Myr) time. There is an often quoted critical SFE of ~30 per cent for a cluster to survive gas expulsion. I reiterate that the SFE is not the critical factor, rather it is the dynamical state of the stars (as measured by their virial ratio) immediately before gas expulsion that is the critical factor. If the stars in a star cluster are born in an even slightly cold dynamical state then the survivability of a cluster can be greatly increased.Comment: 6 pages, 2 figures. Review talk given at the meeting on "Young massive star clusters - Initial conditions and environments", E. Perez, R. de Grijs, R. M. Gonzalez Delgado, eds., Granada (Spain), September 2007, Springer: Dordrecht. Replacement to correct mistake in a referenc

Swimming and risk of asthma and allergies in Portuguese school aged children

[resumo][abstract

Equation of state for Universe from similarity symmetries

In this paper we proposed to use the group of analysis of symmetries of the dynamical system to describe the evolution of the Universe. This methods is used in searching for the unknown equation of state. It is shown that group of symmetries enforce the form of the equation of state for noninteracting scaling multifluids. We showed that symmetries give rise the equation of state in the form $p=-\Lambda+w_{1}\rho(a)+w_{2}a^{\beta}+0$ and energy density $\rho=\Lambda+\rho_{01}a^{-3(1+w)}+\rho_{02}a^{\beta}+\rho_{03}a^{-3}$, which is commonly used in cosmology. The FRW model filled with scaling fluid (called homological) is confronted with the observations of distant type Ia supernovae. We found the class of model parameters admissible by the statistical analysis of SNIa data. We showed that the model with scaling fluid fits well to supernovae data. We found that $\Omega_{\text{m},0} \simeq 0.4$ and $n \simeq -1$ ($\beta = -3n$), which can correspond to (hyper) phantom fluid, and to a high density universe. However if we assume prior that $\Omega_{\text{m},0}=0.3$ then the favoured model is close to concordance $\Lambda$CDM model. Our results predict that in the considered model with scaling fluids distant type Ia supernovae should be brighter than in $\Lambda$CDM model, while intermediate distant SNIa should be fainter than in $\Lambda$CDM model. We also investigate whether the model with scaling fluid is actually preferred by data over $\Lambda$CDM model. As a result we find from the Akaike model selection criterion prefers the model with noninteracting scaling fluid.Comment: accepted for publication versio

Physical distancing and mental well-being in youth population of Portugal and Brazil during the COVID-19 pandemic

Funding Information: This paper was made possible with the scholarship from FCT and to the Unidade de I&D CHRC – Comprehensive Health Research Centre (UI/BD/150908/2021). Also to CAPES (Code 001) and CNPQ (Research Productivity Scholarship Process 304483/2018-4). The databases are anonymous, guaranteeing data confidentiality. Funding Information: Fundação para a ciência e tecnologia (FCT) and the Unidade de I&D CHRC – Comprehensive Health Research Centre (UI/BD/150908/2021). Also to CAPES (Code 001) and CNPQ (Research Productivity Scholarship Process 304483/2018-4) Publisher Copyright: © 2022Background: The COVID-19 pandemic may affect youth's physical and mental well-being, partially because of the countries' rules to contain the virus from spreading. However, there is still uncertainty about the impact of physical distancing on youth's mental health. We aimed to estimate the prevalence of feeling agitated, anxious, down, sad, or low mood (FNF) due to physical distance measures and verify which factors are associated with young Portuguese and Brazilian people. Methods: We used cross-sectional data from the instrument "COVID-19 Barometer: Social Opinion"in Portugal (March 2020 and September 2021) and from "COVID-19 Social Thermometer"in Brazil (August 2020 to April 2021); these surveys included data regarding the health and socioeconomic impact on the population. The health and sociodemographic variables of the two countries were summarized as absolute and relative frequencies. A multivariable logistic regression model was fit by country to estimate the relation between FNF and selected variables of interest. Results: Approximately 36% of the sample studied reported anxiety, agitation, sadness, or low mood almost every day in Portugal and 52% in Brazil due to physical distancing. In Portugal, having more than two comorbidities represented a greater chance of experiencing FNF every day or almost every day (odds ratio [OR] = 1.51 [CI: 1.22-1.87]) than those without comorbidities. In contrast, having a university education level represented a protector factor (OR = 0.76 [CI: 0.67-0.88]). In Brazil, being unemployed increased the chance of FNF compared to students (OR = 11.2). Conclusions: Physical distancing measures have impacted the mental well-being of the young population in Portugal and Brazil. The countries must make a quick effort to attend to and protect young people's well-being and mental health in the changing context of the current pandemic.publishersversioninpres