858 resultados para Through the Canal of Panama
Resumo:
This experimental thesis concerns the study of the long-term behaviour of ancient bronzes recently excavated from burial conditions. The scientific interest is to clarify the effect of soil parameters on the degradation mechanisms of ancient bronze alloy. The work took into consideration bronzes recovered from the archaeological sites in the region of Dobrudja, Romania. The first part of research work was dedicated to the characterization of bronze artefacts using non destructive (micro-FTIR, reflectance mode) and micro-destructive (based on sampling and analysis of a stratigraphical section by OM and SEM-EDX) methods. Burial soils were geologically classified and analyzed by chemical methods (pH, conductivity, anions content). Most of objects analyzed showed a coarse and inhomogeneous corroded structure, often made up of several corrosion layers. This has been explained by the silt nature of soils, which contain low amount of clay and are, therefore, quite accessible to water and air. The main cause of a high dissolution rate of bronze alloys is the alternate water saturation and instauration of the soil, for example on a seasonal scale. Moreover, due to the vicinity of the Black Sea, the detrimental effect of chlorine has been evidenced for few objects, which were affected by the bronze disease. A general classification of corrosion layers was achieved by comparing values of the ratio Cu/Sn in the alloy and in the patina. Decuprification is a general trend, and enrichment of copper within the corrosion layers, due to the formation of thick layers of cuprite (Cu2O), is pointed out as well. Uncommon corrosion products and degradation patterns were presented as well, and they are probably due to peculiar local conditions taking place during the burial time, such as anaerobic conditions or fluctuating environmental conditions. In order to acquire a better insight into the corrosion mechanisms, the second part of the thesis has regarded simulation experiments, which were conducted on commercial Cu-Sn alloys, whose composition resembles those of ancient artefacts one. Electrochemical measurements were conducted in natural electrolytes, such as solutions extracted from natural soil (sampled at the archaeological sites) and seawater. Cyclic potentiodynamic experiments allowed appreciating the mechanism of corrosion in both cases. Soil extract’s electrolyte has been evaluated being a non aggressive medium, while artificial solution prepared by increasing the concentration of anions caused the pitting corrosion of the alloy, which is demonstrated by optical observations. In particular, electrochemical impedance spectroscopy allows assessing qualitatively the nature of corroded structures formed in soil and seawater. A double-structured layer is proposed, which differ, in the two cases, for the nature of the internal passive layer, which result defectiveness and porous in case of seawater.
Resumo:
In this investigation I look at patents and software agents as a way to study broader relation between law and science (the latter term broadly understood as inclusive of science and technology). The overall premise framing the entire discussion, my basic thesis, is that this relation, between law and science, cannot be understood without taking into account a number of intervening factors identifying which makes it necessary to approach the question from the standpoint of fields and disciplines other than law and science themselves.
Resumo:
The quality of fish products is indispensably linked to the freshness of the raw material modulated by appropriate manipulation and storage conditions, specially the storage temperature after catch. The purpose of the research presented in this thesis, which was largely conducted in the context of a research project funded by Italian Ministry of Agricultural, Food and Forestry Policies (MIPAAF), concerned the evaluation of the freshness of farmed and wild fish species, in relation to different storage conditions, under ice (0°C) or at refrigeration temperature (4°C). Several specimens of different species, bogue (Boops boops), red mullet (Mullus barbatus), sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax), during storage, under the different temperature conditions adopted, have been examined. The assessed control parameters were physical (texture, through the use of a dynamometer; visual quality using a computer vision system (CVS)), chemical (through footprint metabolomics 1H-NMR) and sensory (Quality Index Method (QIM). Microbiological determinations were also carried out on the species of hake (Merluccius merluccius). In general obtained results confirmed that the temperature of manipulation/conservation is a key factor in maintaining fish freshness. NMR spectroscopy showed to be able to quantify and evaluate the kinetics for unselected compounds during fish degradation, even a posteriori. This can be suitable for the development of new parameters related to quality and freshness. The development of physical methods, particularly the image analysis performed by computer vision system (CVS), for the evaluation of fish degradation, is very promising. Among CVS parameters, skin colour, presence and distribution of gill mucus, and eye shape modification evidenced a high sensibility for the estimation of fish quality loss, as a function of the adopted storage conditions. Particularly the eye concavity index detected on fish eye showed a high positive correlation with total QIM score.
Resumo:
The 1916 Easter Rising, an unsuccessful insurrection which resulted in the Irish War of Independence, generated a deep change in the political landscape in Ireland. The purpose of this work is to describe this crucial period in the history of Ireland through the voices of Irish writers who expressed their ideas and feelings about the way Ireland was close to gaining its independence. Thanks to songs, poems and literature, I analysed the events of that period through the eyes of the Irish people. Authors like Roddy Doyle and William Butler Yeats were fundamental in examining this topic very thoroughly. Through their works, they were able to convey their knowledge about the events of those years and, at the same time, to give their own opinion, as Irish people, on the topic.
Resumo:
Boris Pasternak’s poemy are acutely self-conscious of their place in the epic tradition. Lieutenant Schmidt (LS) represents one attempt at exploring the parameters of the poema itself as the poet makes a “difficult” transition from “lyric thinking” to “the epic.” In this article I examine this transition against a contemporaneous example in the genre, Tsvetaeva’s Poema of the End (PE). In LS, structural elements of the poema are counterposed to those of PE. While PE amplifies the individual voice, LS muffles what is personal for the sake of the public voice. While PE is atemporal, LS is historical. While PE unfolds on symbolic planes, with elements of plot kept to a bare minimum (a single moment of separation), LS is a plot-driven account based on concrete, documentary material. Finally, while PE is an “overgrown lyric”—representing the “lyric thinking” that Pasternak hopes to transcend— LS is an exploration of the possibilities that a more traditional model of the poema can offer. Although in the present analysis I draw on several theories of poetic genres, this is by no means an exhaustive study of epic versus lyric forms of poetry. Instead, my analysis focuses on those structural and thematic features of the poema that the poets themselves perceived as central to their texts. Pasternak, for his part, develops the structure and thematics of his poema in ways that are inspired by PE, but also, as we will see, in more significant ways, contrast with it.
Resumo:
In my thesis, I explore the cultural history of the French Revolution and its relation to the modern era which ensued. Many historians have studied the French Revolution as it relates to culture, the rise of modernity, and fashion. I combine the unique histories of all three of these aspects to reach an understanding of the history of the French Revolution and fashion’s role in bringing about change. In the majority of literature of costume history, discussion of fashion surrounds its reflective properties. Many historians conclude fashion as a reflection of the broader cultural shifts that occurred during the Revolution. I, on the other hand, propose that fashion is an active force in bringing out cultural change during this time. In exploring fashion as a historical motivator, I examine the aesthetic world of fashion from 1740 to 1815, the modern system of cultural dissemination of fashion through particular historical heroes, and the rise of “taste” and its relation to modern identity. Through aesthetics, culture, and identity, I argue that fashion is a decisive force of culture in that it creates a visual world through which ideas form and communicate.
Resumo:
Misconceptions exist in all fields of learning and develop through a person’s preconception of how the world works. Students with misconceptions in chemical engineering are not capable of correctly transferring knowledge to a new situation and will likely arrive at an incorrect solution. The purpose of this thesis was to repair misconceptions in thermodynamics by using inquiry-based activities. Inquiry-based learning is a method of teaching that involves hands-on learning and self-discovery. Previous work has shown inquiry-based methods result in better conceptual understanding by students relative to traditional lectures. The thermodynamics activities were designed to guide students towards the correct conceptual understanding through observing a preconception fail to hold up through an experiment or simulation. The developed activities focus on the following topics in thermodynamics: “internal energy versus enthalpy”, “equilibrium versus steady state”, and “entropy”. For each topic, two activities were designed to clarify the concept and assure it was properly grasped. Each activity was coupled with an instructions packet containing experimental procedure as well as pre- and post-analysis questions, which were used to analyze the effect of the activities on the students’ responses. Concept inventories were used to monitor students’ conceptual understanding at the beginning and end of the semester. The results did not show a statistically significant increase in the overall concept inventory scores for students who performed the activities compared to traditional learning. There was a statistically significant increase in concept area scores for “internal energy versus enthalpy” and “equilibrium versus steady state”. Although there was not a significant increase in concept inventory scores for “entropy”, written analyses showed most students’ misconceptions were repaired. Students transferred knowledge effectively and retained most of the information in the concept areas of “internal energy versus enthalpy” and “equilibrium versus steady state”.
Resumo:
Using survey and interview data gathered from educators and educational administrators, we investigate school and community impacts of unconventional gas extraction within Pennsylvania's Marcellus Shale region. Respondents in areas with high levels of drilling are significantly more likely to perceive the effects of local economic gains, but also report increased inequality, heightened vulnerability of disadvantaged community members, and pronounced strains on local infrastructure. As community stakeholders in positions of local leadership, school leaders in areas experiencing Marcellus Shale natural gas extraction often face multiple decision-making dilemmas. These dilemmas occur in the context of incomplete information and rapid, unpredictable community change involving the emergence of both new opportunities and new insecurities.