The perfect paint in modern art conservation: a comparative study of 21st century vinyl emulsions

Contemporary painting places, and will continue to place, several questions about its meaning, its chemical nature, its durability and the best way to preserve it. This research aims at putting together comprehensive data on vinyl based paints, including their components, their properties, their aging behavior and their response to selected cleaning products. In this project degradation mechanisms of vinyl binders and formulations used in the 20th and 21st century were studied. Stability over time of selected vinyl polymers was assessed through natural indoor and artificially aging. The objective was to enhance knowledge and understanding of vinyl emulsion formulations and their performance over time. Overall conservation state of pictorial layers namely, adhesion, cohesion and discoloration of selected case studies from the Portuguese artist Julião Sarmento (b.1948) was correlated with the observed molecular level changes studied in laboratory experiments. Sarmento’s paintings were chosen due to conservation concerns (discoloration) on some of his works from the 90’s. Besides, research was carried out to start increasing the knowledge of what can be expected of PVAc based paints in terms of response to conservation treatments namely, surface cleaning. Artificial aging showed that the most recent formulations which are based on a poly(vinyl acetate), poly(vinyl chloride) and polyethylene terpolymer are less stable when compared to some homopolymer formulations. From the four pigments studied, titanium dioxide rutile and a carbon based black proved to be stabilizers for both types of polymer. The mixture lithopone plus calcium carbonate has showed to have a photocatalytic effect on the binders. The studied paintings showed to be in an overall good state of conservation except for the paintings created in the 90’s with white glue and a mixture of white lithoponeand calcium carbonate. Discoloration of this white paint seems to be irreversible and ongoing and is still a major concern. The disapearance of the plasticizer was the only change detected. The current works created by Sarmento are expected to be more stable as they were painted using the rutile titanium dioxide. Immersion/cleaning tests showed that vinyl based paints can be susceptible to water and organic solvents like ethanol as some evidences point to the removal/diffusion of additives from the paint. The observations made point to the need to further proceed in this research field.

Modern piracy

A definição de pirataria ou a desmistificação da sua origem, no tempo e espaço, revela maiores dificuldades do que atualmente. Com este trabalho propusemo-nos a estudar como é que a pirataria era perpetrada e entendida no passado, bem como no presente. Também nos propomos a identificar limitações legais e as medidas operativas no combate à pirataria, como por exemplo: limites conceptuais, lacunas, estratégias, entre outros. Por outro lado, atendemos as soluções encontradas no combate à pirataria sem deixar de observar fraqueza da lei e conflitos entre jurisdições. Por fim, o curso da história dá-nos a seguinte percepção: a pirataria era tida como crime se fosse contra os interesses das nações. O desinteresse dos Estados para reprimir a pirataria possibilitou o seu aumento, proliferação, domínio e sofisticação em certas regiões do Mundo. O presente trabalho tem como objetivo trazer para o centro da discussão os direitos humanos numa perspetiva tripla: proibição da pirataria, supressão e raízes, aliando o estudo de possíveis respostas a dar a esta epidemia.

Modern optimization in earthwork construction

Earthworks tasks are often regarded in transportation projects as some of the most demanding processes. In fact, sequential tasks such as excavation, transportation, spreading and compaction are strongly based on heavy mechanical equipment and repetitive processes, thus becoming as economically demanding as they are time-consuming. Moreover, actual construction requirements originate higher demands for productivity and safety in earthwork constructions. Given the percentual weight of costs and duration of earthworks in infrastructure construction, the optimal usage of every resource in these tasks is paramount. Considering the characteristics of an earthwork construction, it can be looked at as a production line based on resources (mechanical equipment) and dependency relations between sequential tasks, hence being susceptible to optimization. Up to the present, the steady development of Information Technology areas, such as databases, artificial intelligence and operations research, has resulted in the emergence of several technologies with potential application bearing that purpose in mind. Among these, modern optimization methods (also known as metaheuristics), such as evolutionary computation, have the potential to find high quality optimal solutions with a reasonable use of computational resources. In this context, this work describes an optimization algorithm for earthworks equipment allocation based on a modern optimization approach, which takes advantage of the concept that an earthwork construction can be regarded as a production line.

Chest Pain Units: A Modern Way of Managing Patients with Chest Pain in the Emergency Department

It is estimated that 5 to 8 million individuals with chest pain or other symptoms suggestive of myocardial ischemia are seen each year in emergency departments (ED) in the United States 1,2, which corresponds to 5 to 10% of all visits 3,4. Most of these patients are hospitalized for evaluation of possible acute coronary syndrome (ACS). This generates an estimated cost of 3 - 6 thousand dollars per patient 5,6. From this evaluation process, about 1.2 million patients receive the diagnosis of acute myocardial infarction (AMI), and just about the same number have unstable angina. Therefore, about one half to two thirds of these patients with chest pain do not have a cardiac cause for their symptoms 2,3. Thus, the emergency physician is faced with the difficult challenge of identifying those with ACS - a life-threatening disease - to treat them properly, and to discharge the others to suitable outpatient investigation and management.

La asimilación del paradigma moderno de la ciencia en Córdoba. La Physica Particularis de Elías del Carmen Pereyra (1786). Transcripción, versión española y estudio. The assumption of the Modern Paradigm of Science in Córdoba. Physica Particularis by Elías del Carmen Pereira (1786). Transcription, spanish version and study.

El presente trabajo aborda el estudio multidisciplinario de las ideas acerca de la física y la ciencia en general en Córdoba en el siglo XVIII a través de Physica Particularis de Elías del Carmen Pereira (1786), texto manuscrito en lengua latina inédito y recuperado luego de dos siglos de desaparición. El trabajo comprende su transcripción paleográfica, versión española y estudio centrado en la asimilación del paradigma de la ciencia moderna y su enseñanza en la universidad. Se atenderá especialmente a los conceptos que permiten ver en este texto un grado notable de actualización y conocimiento de las ideas de científicos contemporáneos como Nollet y Newton.

Modern climate change in Georgia. Radiatively active small atmospheric admixtures

წიგნში წარმოდგენილია საქართველოში ზოგიერთი ოპტიკურად აქტიური მცირე ატმოსფერული მინარევის მრავალწლიური კვლევის შედეგები. წარმოდგენილია მონაცემები C02, CHx, S02 და აეროზოლების ანთროპოგენური ემისიების შესახებ. დაწვრილებითაა შესწავლილი აეროზოლების თვლადი კონცენტრაციის ვერტიკალური განაწილება ტროპოსფეროში საქართველოს სხვადასხვა რეგიონისთვის. ჩატარებულია ოზონის საერთო რაოდენობის, ატმოსფერული აეროზოლების ოპტიკური სიმკვრის და სხვა ნაერთების გრძელვადიანი ვარიაცების დეტალური ანალიზი. წარმოდგენილია ზოგიერთი ნაერთის გავლენის თეორიული შეფასება საქართველოში მზის პირდაპირი და გაბნეული რადიაციის რეჟიმზე.

Ostrich egg-shell cups of Mesopotamia and the ostrich in ancient and modern times / by Berthold Laufer. 9 plates and 10 text-figures.

no.23(1926)

La il·lustració britànica

Estudi elaborat a partir d’una estada a la School of Modern Languages de la University of London, Gran Bretanya, entre agost i desembre del 2006. L’objectiu de la recerca consisteix en exposar el moviment empirista a través de Hume, Locke, Berkeley i altres filòsofs del segle XVIII. A més, s’analitza la filosofia escocesa del sentit comú, ja que va influenciar la filosofia catalana durant la “Renaixença”. El seu fundador, Thomas Reid, és conegut perquè va introduir una filosofia que no seguia l’escepticisme dels filòsofs citats. Sintetitzant, Hume va afirmar que l’experiència del sentit consisteix exclusivament en idees o impressions subjectives en la ment. Una resposta aquest “sistema ideal” va ser la filosofia del sentit comú que es va desenvolupar com a reacció a l’escepticisme de David Hume i altres filòsofs escocesos. Contra aquest “sistema ideal” la nova escola considera que l’experiència ordinària dels homes dona instintivament certes creences de la pròpia existència; de la existència dels objectes reals directament percebuts; i de “principis bàsics” basats en creences morals i religioses. Entre 1816 a 1870 la doctrina escocesa va ser adoptada com a filosofia oficial a França. Els seus principis van obtenir força a través de Víctor Cousin i de la traducció de les obres de Thomas Reid al francès per Jouffroy. Serà doncs, a partir de les traduccions franceses que Ramon Martí d’Eixalà va introduir a Catalunya la filosofia escocesa (no existeix cap prova que Martí d’Eixalà hagués conegut les versions angleses de les obres de Reid). En conclusió, el moviment escocès del sentit comú va influenciar l’escola catalana de filosofia.

Modern British Retailing in the Late 20th Century: Increasing Value?

not available

The marginal utility of money: A modern Marshallian approach to consumer choice

We reformulate neoclassical consumer choice by focusing on lambda, the marginal utility of money. As the opportunity cost of current expenditure, lambda is approximated by the slope of the indirect utility function of the continuation. We argue that lambda can largely supplant the role of an arbitrary budget constraint in partial equilibrium analysis. The result is a better grounded, more flexible and more intuitive approach to consumer choice.