MODELING AND SIMULATION OF THERMOELECTRIC PLANT OF COMBINED CYCLES AND ITS ENVIRONMENTAL IMPACT

The impact any power plant has upon the environment must be minimized as much as possible. Due to its high efficiency, low emission levels and low cooling requirements, combined cycle plants are considered to be environmentally friendly. This study evaluates the effect of operational conditions on pollutants (CO, CO2, SOx, NOx) emissions levels, waste-heat and wastewater of a combined-cycle natural gas and steam power plant. The HYSYS process simulation was used for modelling and simulation. The study clearly shows that the absolute quantity of pollutants emitted is high. Also, it was possible to verify that the unit operate in the condition of minimal emissions regarding the maximum possible, and thus a reduction or elimination of such pollutants is not possible

Near-infrared spatially resolved spectroscopy of (136108) Haumea's multiple system

The transneptunian region of the solar system is populated by a wide variety of icy bodies showing great diversity. The dwarf planet (136108) Haumea is among the largest TNOs and displays a highly elongated shape and hosts two moons, covered with crystalline water ice like Hamuea. Haumea is also the largest member of the sole TNO family known to date. A catastrophic collision is likely responsible for its unique characteristics. We report here on the analysis of a new set of observations of Haumea obtained with SINFONI at the ESO VLT. Combined with previous data, and using light-curve measurements in the optical and far infrared, we carry out a rotationally resolved spectroscopic study of the surface of Haumea. We describe the physical characteristics of the crystalline water ice present on the surface of Haumea for both regions, in and out of the Dark Red Spot (DRS), and analyze the differences obtained for each individual spectrum. The presence of crystalline water ice is confirmed over more than half of the surface of Haumea. Our measurements of the average spectral slope confirm the redder characteristic of the spot region. Detailed analysis of the crystalline water-ice absorption bands do not show significant differences between the DRS and the remaining part of the surface. We also present the results of applying Hapke modeling to our data set. The best spectral fit is obtained with a mixture of crystalline water ice (grain sizes smaller than 60 micron) with a few percent of amorphous carbon. Improvements to the fit are obtained by adding ~10% of amorphous water ice. Additionally, we used the IFU-reconstructed images to measure the relative astrometric position of the largest satellite Hi`iaka and determine its orbital elements. An orbital solution was computed with our genetic-based algorithm GENOID and our results are in full agreement with recent results.Comment: Accepted for publication in A&

Efeito de agentes desinfestantes e antioxidantes no estabelecimento de ápices caulinares in vitro de cultivares de bananeira.

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HEAT TRANSFER INVESTIGATION FOR A MULTILAYER INSULATION SYSTEM VIA RADIATIVE-CONDUCTIVE APPROACH UNDER LOW TEMPERATURE CONDITIONS IN SPACE

Thermal insulation is an important area, not restricted to mechanical engineering, but widely studied in environmentalissues, such as global warming and, above all, energy-saving, since controlling the heat flux on microprocessorsthrough temperature control on components in space applications. This work focuses on controlling the temperature incomponents that could not lose or gain so much heat in space, especiallywhen the overall safety of sending satellites onspecific missions is required. To ensure that, Multilayer Insulation (MLI) is used. With fluid mechanics and radiation-conductionheat transfer theory, it was possible to calculate the transient and stationary temperature field and heat flux inMLI. The boundary temperatures are specified at 300K and 4K. The results, from solving the resulting discretized ODE,simulated with fsolve and odeintScipy subroutines in Python, able to solve the equations numerically, were shown. Thedata given by the simulation was able to indicate the impacts of varying the layer density, emissivity of screen, the distancebetween screens and the perforation coefficient in stationary and transient approaches. A way to simulate the performanceof MLI numerically was presented. Modifying emissivity (e) showed variations higher than in the perforation coefficient(ξ). Layer density controls the distance between layers (d ), changing the conduction heat transfer. In the transient casesimulation, it was possible to notice that varying parameters impact in time to reach steady-state and final temperature

Modelação e Previsão do fluxo de Turismo em Portugal: Perspetivas para uma gestão estratégica

Purpose: The increase of Tourism in Portugal, as well as the companies related to it, it is necessary to analyze and forecast the flow of tourists so that the management of the business is endowed with a competitive strategy. Given the changes in the 'recent' dynamics of tourism data, this article discusses the contributions and limitations of using classical forecasting methodologies, when applied to this sector, namely to the number of overnight stays in tourist accommodation establishments in Portugal. Methodology: The study focuses on the modeling and forecasting of time series related to the number of monthly overnight stays, in tourist accommodation establishments in Portugal, between January 2002 and March 2022. As a result of some suggestions contained in the scientific literature, it was resorted the Exponential Smoothing (ETS) methodologies. In computational terms, we used the Jupyter computational environment, with the Python programming language (version 3.7.3). Findings: The results were presented and discussed through the analysis of two time series: (1) Total number of overnight stays in tourist accommodation establishments in Portugal – Total series; (2) Number of overnight stays spent by residents in Portugal in tourist accommodation establishments in Portugal – Residents series. Overall, from the analysis of the time series, there was a growth of Tourism in Portugal since 2002, with a visible drop in 2020, due to the pandemic situation. Regarding the ETS methodologies used in the modeling and forecasting, although they corresponded positively in the forecast of the Total series (with some error), the same did not happen in the Residents series. In this series, due to the recent dynamics that are completely atypical, it appears that the ETS methodologies, potentially more adequate, do not converge, in general. However, it is important to mention that it was the overnight stays of residents that, in the pandemic period, dictated the dynamics present in the Total series. Research limitations: The literature points to a good performance of ETS methodologies in time series with characteristics present in the series under study (with the presence of a trend cycle and clear seasonality), a fact that motivated its choice. However, the difficulty of these methodologies in dealing with abrupt breaks in the data history was evident in this study. Despite how adjusted the forecasts are, the highlight is the non-convergence of some models that could be better adjusted to the historical data. In this sense, it is necessary to search for alternative forecasting methodologies, where Machine Learning methodologies, namely Deep Learning (Deep Neural Networks) have been pointed out in the scientific literature as quite promising. This will be the next step of the investigation. Originality: Given the importance that Tourism has both in the economic and social dimension of Portugal, and being a very volatile and constantly changing sector, it is imperative to define a strategy for future action to understand how, internally, the sector can define policies to avoid situations of external dependence. In addition to a current analysis of the data history, resulting from an atypical period of pandemic, we need to critically evaluate the predictive capacity of (classical) econometric models, which can be used by the industry related to tourism. This not only contributes to a better understanding of the phenomenon under study, but also constitutes a tool to support decision-making.info:eu-repo/semantics/publishedVersio

Transplante autólogo de células estaminais em leucemiamielóide aguda: factores com Influência na sobrevida: experiência de 13 anos de uma Instituição

© Ordem dos MédicosWe report our results of autologous stem cell transplantation (SCT) in patients with AML during the last 13 years. Between August 1990 and December 2003, 42 patients with acute myeloid leukemia (AML) received an autologous SCT. Patients were classified as standard risk if first complete remission (CR) was induced after one or two chemotherapy regimens and the white blood cell count at presentation was below 50,000/mL (n=12), while patients requiring more than two induction regimens to attain first CR and with CR2 ou more advanced disease and/or had a higher white blood cell count at presentation were defined as high risk (n=30). Twenty one patients were transplanted in first CR. The median patient age was 24 years (range, 2-56 years), and the median time interval from diagnosis to autologous SCT was 9 months (range 3-87 months). The conditioning regimen for SCT consisted of busulfan (BU) 16 mg/kg and melfalan (MEL) 180 mg/m2 (BUMEL) in 17 (40%) patients and busulfan 16 mg/kg and VP-16 60 mg/kg (BUVP16) in 22 (52%) patients. Three patients received a different conditioning regimen with BCNU 300 mg/m2, VP16 2 g/m2 and melphalan 160 mg/m2 (BEM). Twenty five (60%) patients received bone marrow (BM), 11 (26%) patients received peripheral blood stem cells (PBSC) and 6 patients (14%) received BM plus PBSC. With a median follow-up of 7 years, the 13 year overall survival (OS) and diseasefree survival (DFS) of all patients is 52% and 40%, respectively. In univariate analysis, males had a significantly superior DFS than females (55% vs 22%, p=0.003), and patients younger than 15 years of age had significantly superior OS and DFS than older patients (50% vs 35%, p=0.05; and 50% vs 28%, p=0.03, respectively). Patients with FAB M3 subtype also had a superior OS than the other FAB subtypes (100% vs 44%, p=0.05). There was a strong statistical correlation between risk group and survival. In fact, the patients with standard risk had a superior OS and DFS than those with high risk disease (67% vs 23%, p=0.0004; and 50% vs 27%, p=0.01, respectively). When patients with FAB M3 disease were excluded from the analysis, the group with standard risk continue to have a superior OS and DFS (67% vs 13%, p=0.008; and 50% vs 14%, p=0.02, respectively). We conclude that autologous SCT is an effective treatment in AML with the possibility of long survivorship, particularly in patients with standard risk disease.info:eu-repo/semantics/publishedVersio

Transplante alogénico de células estaminais em doentes com síndrome mielodisplásica: análise de acordo com o Índice de Prognóstico Internacional

© Ordem dos MédicosWe determined the outcome of patients with myelodysplastic syndrome (MDS) and secondary acute myeloid leukemia (sAML) after allogeneic stem cell transplantation according to their international prognostic scoring system (IPSS) risk categories at diagnosis. A total of 11 females and 7 males, with a median age of 45 years, were transplanted. With a median follow-up of 60 months, the 6-year actuarial event-free survival (EFS) for Less Advanced (Low and Intermediate-1 risk IPSS) and Advanced (Intermediate-2 and High risk IPSS) MDS was 71.4% and 43.6%, respectively (p=0.002). We did not observe a difference in EFS depending on cytogenetics at diagnosis (good risk 53.8% Vs intermediate and high risk 53.3%, p=ns), neither on the type of conditioning regimen used (myeloablative 50% Vs reduced intensity 52.2%, p=ns). Our results support that IPSS score at diagnosis may be used to predict EFS in patients with MDS undergoing allogeneic SCT.Neste estudo avaliámos o valor preditivo do índice prognóstico internacional (IPSS) na altura do diagnóstico em doentes com síndrome mielodisplásica (SMD) e leucemia mielóide aguda secundária submetidos a transplante alogénico de células estaminais. Foram transplantados um total de 11 mulheres e sete homens, com uma mediana de idades de 45 anos. Com um seguimento mediano de 60 meses, a sobrevivência livre de eventos aos 6 anos nos doentes com doença menos avançada (IPSS Risco Baixo e Intermédio 1) e com doença avançada (IPSS Intermédio 2 e Alto Risco) foi de 71.4% e 43.6%, respectivamente (p=0.002). Não observámos diferenças significativas na sobrevivência livre de eventos de acordo com a análise citogenética na altura do diagnóstico (risco bom 53,8% VS risco intermédio e alto 53,3%, p=ns) nem com o tipo de regime de condicionamento utilizado (mieloablativo 50% VS intensidade reduzida 52,2%, p=ns). Os nossos resultados demonstram que o IPSS na altura do diagnóstico pode ser utilizado para predizer a sobrevivência livre de eventos em doentes com SMD submetidos a transplante alogénico de células estaminaisinfo:eu-repo/semantics/publishedVersio