991 resultados para Technological parameters


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This work presents the archaeometallurgical study of a group of metallic artefacts found in Moinhos de Golas site, Vila Real (North of Portugal), that can generically be attributed to Proto-history (1st millennium BC, Late Bronze Age and Iron Age). The collection is composed by 35 objects: weapons, ornaments and tools, and others of difficult classification, as rings, bars and one small thin bent sheet. Some of the objects can typologically be attributed to Late Bronze Age, others are of more difficult specific attribution. The archaeometallurgical study involved x-ray digital radiography, elemental analysis by micro-energy dispersive X-ray fluorescence spectrometry and scanning electron microscopy with energy dispersive spectroscopy, microstructural observations by optical microscopy and scanning electron microscopy. The radiographic images revealed structural heterogeneities frequently related with the degradation of some artefacts and the elemental analysis showed that the majority of the artefacts was produced in a binary bronze alloy (Cu-Sn) (73%), being others produced in copper (15%) and three artefacts in brass (Cu-Zn(-Sn-Pb)). Among each type of alloy there’s certain variability in the composition and in the type of inclusions. The microstructural observations revealed that the majority of the artefacts suffered cycles of thermo-mechanical processing after casting. The diversity of metals/alloys identified was a discovery of great interest, specifically due to the presence of brasses. Their presence can be interpreted as importations related to the circulation of exogenous products during the Proto-history and/or to the deposition of materials during different moments at the site, from the transition of Late Bronze Age/Early Iron Age (Orientalizing period) onwards, as during the Roman period.

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INTRODUCTION: Discrepancy between the intensity of pulmonary congestion and the grade of cardiomegaly seems to be a common finding of Chagas cardiomyopathy, in spite of significant systolic dysfunction of the left ventricle. Its mechanism has not been established. The aim of this study was to investigate pulmonary congestion and to analyze if it correlated with Doppler echocardiographic parameters in patients with Chagas dilated cardiomyopathy. METHODS: Fifty-five patients with positive serology tests for Trypanosoma cruzi and Chagas dilated cardiomyopathy were studied. Chest x-rays, Doppler echocardiogram and plasmatic brain natriuretic peptide levels were obtained in all patients. The degree of pulmonary venous vessels changes on chest x-ray was graded using a pulmonary congestion score, and then compared to Doppler echocardiographic parameters. RESULTS: Mean age was 48.5 ± 11.2 years and 29% were women. The majority (95%) of patients were in NYHA functional class I and II. Mild pulmonary congestion by chest x-ray was found in 80% of the patients. In a multivariate analysis, left ventricular ejection fraction, right ventricular TEI index and the color M-mode velocity correlated with the degree of pulmonary congestion. CONCLUSIONS: Pulmonary venous changes on chest x-rays are frequent, but usually mild in patients with Chagas dilated cardiomyopathy. The degree of pulmonary congestion correlates with Doppler echocardiographic left and right ventricular dysfunction and with color M-mode velocity.

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INTRODUCTION: Despite significant left ventricular (LV) systolic dysfunction and cardiomegaly, pulmonary congestion does not seem to be a major finding in Chagas' cardiomyopathy (CC). This study sought to identify echocardiographic parameters associated with pulmonary congestion in CC and in dilated cardiomyopathy of other etiologies, such as non-CC (NCC), and to compare pulmonary venous hypertension between the two entities. METHODS: A total of 130 consecutive patients with CC and NCC, with similar echocardiographic characteristics, were assessed using Doppler echocardiography and chest radiography. Pulmonary venous vessel abnormalities were graded using a previously described pulmonary congestion score, and this score was compared with Doppler echocardiographic parameters. RESULTS: NCC patients were older than CC patients (62.4 ± 13.5 × 47.8 ± 11.2, p = 0.00), and there were more male subjects in the CC group (66.2% × 58.5%, p = 0.4). Pulmonary venous hypertension was present in 41 patients in the CC group (63.1%) and in 63 (96.9%) in the NCC group (p = 0.0), the mean lung congestion score being 3.2 ± 2.3 and 5.9 ± 2.6 (p = 0.0), respectively. On linear regression multivariate analysis, the E/e' ratio (β = 0.13; p = 0.0), LV diastolic diameter (β = 0.06; p = 0.06), left atrial diameter (β = 0.51; p = 0.08), and right ventricular (RV) end-diastolic diameter (β = 0.02; p = 0.48) were the variables that correlated with pulmonary congestion in both groups. CONCLUSIONS: Pulmonary congestion was less significant in patients with CC. The degree of LV of systolic and diastolic dysfunction and the RV diameter correlated with pulmonary congestion in both groups. The E/e' ratio was the hallmark of pulmonary congestion in both groups.

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Although modern combined antiretroviral therapies (cART) result in lower morbidity and mortality and a visible improvement of clinical and laboratory parameters in HIV-infected, it is known that their long-term use contributes to appearance of the many events unrelated to AIDS such as cardiovascular diseases, cancer and osteoporosis, comorbidities which have been proposed as some of the most important that deprive the majority of infected to present an even better prognosis. This is because even with a decrease in inflammation and immune activation after drug intervention to the patient, these parameters remain higher than those shown by healthy individuals and the imbalance of cytokine profiles also persists. Therefore, evaluations of other biomarkers in clinical practice are needed to complement the exams already carried out routinely and allow more effective monitoring of HIV patients. This review aims to investigate the role of cytokines as potential markers showing studies on their behavior in various stages of HIV infection, with or without cART.

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In modern society, energy consumption and respect for the environment have become essential aspects of urban planning. The rising demand for alternative sources of energy, coupled with the decline in the construction sector and material usage, gives the idea that the thinking on modern cities, where attention is given to reduced energy consumption, savings, waste recycling and respect for the surrounding environment, is being put into practice. If we examine development of the city over recent centuries, by means of the theories of the most famous and influential urban planners, it is possible to identify the major problems caused by this type of planning. For this reason, in recent urban planning the use of systems of indicators that evaluate and certify land environmentally and energetically guides the master plan toward a more efficient city model. In addition the indicators are targeted on key factors determined by the commissioner or the opportunities the territory itself provides. Due the complexity of the environmental mechanics, the process of design and urban planning has become a challenging issue. The introduction of the indicators system has made it possible to register the life of the process, with a spiral route that allows the design itself to be refined. The aim of this study, built around the creation of a system of urban sustainability indicators that will evaluate highly eco-friendly cities, is to develop a certification system for cities or portions of them. The system will be upgradeable and objective, will employ real data and will be concerned with energy production and consumption.

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White Color tuning is an attractive feature that Organic Light Emitting Diodes (OLEDs) offer. Up until now, there hasn’t been any report that mix both color tuning abilities with device stability. In this work, White OLEDs (W-OLEDs) based on a single RGB blend composed of a blue emitting N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) doped with a green emitting Coumarin-153 and a red emitting 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM1) dyes were produced. The final device structure was ITO/Blend/Bathocuproine (BCP)/ Tris(8-hydroxyquinolinato)aluminium (Alq3)/Al with an emission area of 0.25 cm2. The effects of the changing in DCM1’s concentration (from 0.5% to 1% wt.) allowed a tuning in the final white color resulting in devices capable of emitting a wide range of tunes – from cool to warm – while also keeping a low device complexity and a high stabilitty. Moreover, an explanation on the optoelectrical behavior of the device is presented. The best electroluminescense (EL) points toward 160 cd/m2 of brightness and 1.1 cd/A of efficiency, both prompted to being enhanced. An Impedance Spectroscopy (IS) analysis allowed to study both the effects of BCP as a Hole Blocking Layer and as an aging probe of the device. Finally, as a proof of concept, the emission was increased 9 and 64 times proving this structure can be effectively applied for general lighting.

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Diffusion of Innovation is a topic of interest for researchers and practitioners. Although substantial research is conducted on user categories, researchers often focus on the first half of the curve, ignoring the late adopters. We conduct two studies to measure the attributes of late adopters. In our first study of mobile phone users, we develop the Late-Adopter Scale. We then test it on a sample of laptop users. This scale is multi-dimensional, presents nomological and discriminant validity and has three dimensions: 1) rate of adoption, 2) resistance to innovation, and 3) skepticism. Findings reveal that all three Late Adopter Scale dimensions are significantly associated with low price preference. Moreover, in both samples skepticism is associated with high preference for simple products, lower leading edge status, and lower product involvement. Discussion focuses on implications of this new scale to theory and practice of new product development and diffusion of innovation.

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Wireless Sensor Networks(WSN) are networks of devices used to sense and act that applies wireless radios to communicate. To achieve a successful implementation of a wireless device it is necessary to take in consideration the existence of a wide variety of radios available, a large number of communication parameters (payload, duty cycle, etc.) and environmental conditions that may affect the device’s behaviour. However, to evaluate a specific radio towards a unique application it might be necessary to conduct trial experiments, with such a vast amount of devices, communication parameters and environmental conditions to take into consideration the number of trial cases generated can be surprisingly high. Thus, making trial experiments to achieve manual validation of wireless communication technologies becomes unsuitable due to the existence of a high number of trial cases on the field. To overcome this technological issue an automated test methodology was introduced, presenting the possibility to acquire data regarding the device’s behaviour when testing several technologies and parameters that care for a specific analysis. Therefore, this method advances the validation and analysis process of the wireless radios and allows the validation to be done without the need of specific and in depth knowledge about wireless devices.

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The evolution of a technology and the understanding of the moment in its life cycle is of the utmost importance to the entry strategy devised by any company. Having the entry of EDP Brazil on the micro-generation market as background, the present workproject attempts to summarize the most important topics in management literature concerning the theory of technology life-cycles and the updated literature on developments of photovoltaic technology to infer the current positioning of this technology in the theoretical models. The need for this type of work stems from the very common lack of bridging between the academic research of economic aspects relevant to the evolution of technologies and the agents of research on specific technological issues. When this occurs, namely due to the external nature of research to companies, thereby escaping the harsh economic controls of a profit seeking enterprise, the evolution many times lacks the appropriate framework to be studied on a more forward looking manner and to allow for management decisions to be based on.

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In this research, five types of polymer repair materials were selected for investigation of the influence of sample shape, deformation rate and test temperature on the mechanical properties determined with an uniaxial tensile test. The results showed the clear effect of measurement conditions on tensile strength, elongation and modulus of elasticity. The highest tensile strength and modulus of elasticity were exhibited by epoxy resin for the filling of concrete cracks, which achieved 1% elongation. The lowest coefficient of dispersion characterized the results of tensile test carried out using dumbbell samples at a deformation rate of 50 mm/min. The effect of temperature varied with the material type.

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COST (European Co-operation in the field of scientific and technical research) is the longest running framework for research co-operation iri Europe, having been established in 1971 by a Ministerial Conference attended by Ministers for Science and Technology from 19 countries. Today COST is used by the scientific communities of 35 European countries to cooperate in exchanging knowledge and technology developed within research projects supported by national or European funds. The main objective of COST is to contribute to the realization of the European Research Área (ERA) anticipating and complementing the activities of the' Framework Programmes, constituting a "bridge" towards the scientific communities of emerging countries, increasing the mobility of researchers across Europe and fostering the establishment of "Networks of Excelience". Another essential objective is the knowledge transfer between the scientific soc'iety and industry. It is widely acknowledged that European scientific performance in relation to investment in science is excellent but technological and commercial performance has steadily worsened. The present paper discusses how the COST Action's instruments, from training schools to short scientific missions and workshops have been used within The COST ACTION FP11O1 Assessment, Reinforcement and Monitoring of Timber Structures to achieve such objectives.

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In order to compare the development of strata in the early stages of secondary forest succession with vessel parameters of the tree species, a forest inventory was carried out in 4-year (Q1: 48 m2), 11-year (Q2: 400 m2) and 20-year (Q3: 400 m2) forests and vessel parameters were investigated from stem cross sections of 18 species obtained in Q2. Thirty three species (21 families), 77 species (35 families), 39 species (20 families) were found in Ql, Q2, Q3, respectively. The percentage of dead individuals, dead stems and the percentage of individuals with multiple stems increased with time after clear cutting. Also, the total D2H of Q3 was 26.1 times that of Q1, and the development of strata started in Q2 and Q3. The image analysis of vessel size, area and number of vessels revealed that species which reach the forest canopy had a large D2H value, vessel diameter and area, while species which remain near the forest floor had smaller ones. Poecilanthe effusa (Huber) Ducke is an example of the latter case, with a large number of individuals and abundant sprouting of new stems from stumps, but with high mortality.

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Considering that vernacular architecture may bear important lessons on hazard mitigation and that well-constructed examples showing traditional seismic resistant features can present far less vulnerability than expected, this study aims at understanding the resisting mechanisms and seismic behavior of vernacular buildings through detailed finite element modeling and nonlinear static (pushover) analysis. This paper focuses specifically on a type of vernacular rammed earth constructions found in the Portuguese region of Alentejo. Several rammed earth constructions found in the region were selected and studied in terms of dimensions, architectural layout, structural solutions, construction materials and detailing and, as a result, a reference model was built, which intends to be a simplified representative example of these constructions, gathering the most common characteristics. Different parameters that may affect the seismic response of this type of vernacular constructions have been identified and a numerical parametric study was defined aiming at evaluating and quantifying their influence in the seismic behavior of this type of vernacular buildings. This paper is part of an ongoing research which includes the development of a simplified methodology for assessing the seismic vulnerability of vernacular buildings, based on vulnerability index evaluation methods.

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This paper presents a proposal for a management model based on reliability requirements concerning Cloud Computing (CC). The proposal was based on a literature review focused on the problems, challenges and underway studies related to the safety and reliability of Information Systems (IS) in this technological environment. This literature review examined the existing obstacles and challenges from the point of view of respected authors on the subject. The main issues are addressed and structured as a model, called "Trust Model for Cloud Computing environment". This is a proactive proposal that purposes to organize and discuss management solutions for the CC environment, aiming improved reliability of the IS applications operation, for both providers and their customers. On the other hand and central to trust, one of the CC challenges is the development of models for mutual audit management agreements, so that a formal relationship can be established involving the relevant legal responsibilities. To establish and control the appropriate contractual requirements, it is necessary to adopt technologies that can collect the data needed to inform risk decisions, such as access usage, security controls, location and other references related to the use of the service. In this process, the cloud service providers and consumers themselves must have metrics and controls to support cloud-use management in compliance with the SLAs agreed between the parties. The organization of these studies and its dissemination in the market as a conceptual model that is able to establish parameters to regulate a reliable relation between provider and user of IT services in CC environment is an interesting instrument to guide providers, developers and users in order to provide services and secure and reliable applications.

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The monitoring data collected during tunnel excavation can be used in inverse analysis procedures in order to identify more realistic geomechanical parameters that can increase the knowledge about the interested formations. These more realistic parameters can be used in real time to adapt the project to the real structure in situ behaviour. However, monitoring plans are normally designed for safety assessment and not especially for the purpose of inverse analysis. In fact, there is a lack of knowledge about what types and quantity of measurements are needed to succeed in identifying the parameters of interest. Also, the optimisation algorithm chosen for the identification procedure may be important for this matter. In this work, this problem is addressed using a theoretical case with which a thorough parametric study was carried out using two optimisation algorithms based on different calculation paradigms, namely a conventional gradient-based algorithm and an evolution strategy algorithm. Calculations were carried for different sets of parameters to identify several combinations of types and amount of monitoring data. The results clearly show the high importance of the available monitoring data and the chosen algorithm for the success rate of the inverse analysis process.