Background: Very occasionally, when a fetus is developing in the womb, problems occur with the normal processes controlling closure of the muscles of the abdominal wall and, as a result, some of the abdominal contents develop outside of the body. This is known as an abdominal wall defect. If the pregnancy continues to term, the newborn infant will need specialised surgical care. This situation occurs so infrequently that even a dedicated surgical centre will care for very few of these women and their babies in a year. Many centres have shared their experiences of managing these babies in the published literature but the majority of reports have included only a few infants. The focus of most previous studies has been to describe what happens to these newborn infants between birth and first discharge from hospital from a purely clinical perspective. Aim: To explore methodologies to holistically understand the short and longer-term outcomes of children born with abdominal wall defects and to use the information to improve the care of future affected infants. Methods: The quality of the published literature on short-term outcomes of children born with gastroschisis was scrutinised in a systematic review. The accompanying meta-analysis used published data as a means of identifying population outcome estimates. Two national population-based cohort studies were undertaken, exploring the short-term outcomes of children born with exomphalos and the outcomes at seven to ten years of children born with gastroschisis. The latter study included an assessment of childhood outcomes from the point of view of the children themselves, along with their parents. Further parental perspectives on experiences of care were explored in a qualitative analysis of in-depth interviews with parents of children born with exomphalos. Findings: Short-term outcomes of children born with gastroschisis have been published in a large number of small studies. Pooling the published data, where possible allowed the production of population estimates but heterogeneity between studies was marked. One in fourteen children born with gastroschisis died before their first birthday when managed in developed countries. Those who developed bowel complications in utero, had an increased risk of dying before one-year. The assessment of childhood outcomes for this latter group of children, who made up 11% of the population cohort, revealed a bleak outlook for many, of with one in three either dying or requiring complex surgery to gain allow them to be able to be fed via their gut, before their ninth birthday. Due to methodological limitations, the extent of neurological and gastrointestinal morbidity among survivors in the cohort is unclear, but the findings of both the highly selected responses from the parent report and those of the clinical study provide enough concern to suggest that alternative methodologies need to be explored to identify the extent of ongoing sequelae as children grow older. The live-born population of children with exomphalos is highly varied and a large burden of comorbidity was identified, however, two-thirds of infants were able to be have their abdominal wall defect surgically closed with a low-rate of early complications. A variety of techniques are employed by UK surgeons when the defect cannot be easily closed and evidence to guide management choice will be difficult to obtain using standard techniques due to the small number of these infants born annually in the UK. Parental experiences echoed the variability in management approach and in some cases highlighted a lack of respect for parental perspectives on management choice. Conclusion: Children born with abdominal wall defects represent a spectrum from those with severe comorbidity who will need ongoing care, to those who have a straightforward course and a relatively short stay in hospital. Methods of risk-stratifying infants for the purposes of outcome assessment have been explored. This approach is crucial to contextualising the progress of an individual infant and counselling their parents about their likely prognosis.

Circulation control involves tangentially blowing air around a rounded trailing edge in order to augment the lift of a wing. The advantages of this technique over conventional mechanical controls are reduced maintenance and lower observability. Despite the technology first being proposed in the 1960s and well-studied since, circulation control is not in widespread use today. This is largely due to the high mass flow requirements. Increasing the jet velocity increases both the efficiency (in terms of mass flow) and effectiveness. However, as the jet velocity exceeds the speed of sound, shock structures form which cause the jet to separate. Recent developments in the field of fluidic thrust vectoring (FTV) have shown that an asymmetrical convergent-divergent nozzle capable of producing an irrotational vortex (IV) has the potential to prevent separation through eliminating stream-wise pressure gradients. In this study, the feasibility of preventing separation at arbitrarily high jet velocities through the use of asymmetrical nozzle geometries designed to maintain irrotational (and stream-wise pressure gradient free) flow is explored. Furthermore, the usefulness of an adaptive nozzle geometry for the purpose of extending circulation control device efficiency and effectiveness is defined. Through a series of experiments, the flow physics of supersonic curved wall jets is characterised across a range of nozzle geometries. IV and equivalent area ratio symmetrical convergent-divergent nozzles are compared across three slot height to radius ratios (H/R): H/R = 0.1, H/R = 0.15, H/R = 0.2. The conclusion of this study is that at low H/R (0.1 and 0.15), there is no significant difference in behaviour between IV and symmetrical nozzles, whilst at high H/R (0.2), the IV nozzles begin separating whilst correctly expanded due to the propagation of pressure upstream from the edge of the reaction surface via the boundary layer. Consequently, it is shown that symmetrical nozzles of equivalent mass flow at high H/R have a higher separation NPR compared to IV nozzles. Specifically, the elimination of favourable, in addition to adverse stream-wise pressure gradients contradicts the expected behaviour of IV nozzles. The separation NPR for nozzles tested in this study, in addition to past studies is subsequently plotted against the throat height to radius ratios (A*/R). This shows that in fact, no previous experiments have shown a higher separation NPR for IV nozzles compared to symmetrical nozzles of equivalent mass flow. The overall outcome is that neither fixed geometry IV, nor adaptive nozzles are justified to maintain attachment, or to improve efficiency. This is because fixed nozzle geometries designed for higher separation NPR do not show any performance deficit when operating at lower NPRs. However, the throat height could be varied to maximise effectiveness (at the expense of mass flow). The contributions to new knowledge made by this study are as follows: the development of a new method of combining shadowgraph and schlieren images to simplify and enhance visualisation of supersonic flows; the use of pressure sensitive paint (PSP) to study the structure of the supersonic curved wall jet before and after separation; the identification of a clear mechanism for the separation of supersonic curved wall jets, valid over a broad range of nozzle geometries (including a clarification of previously unexplained behaviour witnessed in prior studies); the explanation that reattachment hysteresis occurs due to the upstream movement of the point of local separation at full separation (specifically, this explains why certain geometries such as backward-facing steps prevent reattachment hysteresis).

Thermal improvement of traditional and historic buildings is going to play a crucial role in the achievement of established carbon emission targets. The suitable retrofit options for traditional buildings are, however, very limited and their long term performance is still uncertain. Evaluation of risks, prior to any alteration of building physics, is critical to avoid future damage to the fabric or occupants’ health. Moisture dynamics in building envelopes are affected by the enclosure’s geometry, materials properties and external and internal boundary conditions. Since the internal boundary is heavily influenced by users, understanding their behaviour is essential to predict the outcome of energy retrofit measures more accurately. The effect of user behaviour on energy demand has been extensively investigated; however, its impact on the hygrothermal performance of the envelopes has barely been explored. This research approached the connection between users and buildings from a new angle looking at the effect that user behaviour has on moisture dynamics of buildings’ envelopes after the retrofit. Qualitative and quantitative research methods were used to develop a holistic evaluation of the question. Firstly, factors influencing the adoption of energy efficiency measures in traditional buildings were explored by means of semi-structured interviews with private owners and project managers. Subsequently, a multi-case study including interviews with occupants and monitoring of environmental conditions was conducted. Data collected at this stage was used to explore users’ daily practices of comfort and to characterise the internal climate of traditional dwellings. Lastly, users’ impact was quantified using Heat, Air and Moisture (HAM) numerical simulation. This allowed for the evaluation of the hygrothermal performance of walls under different internal climate scenarios. Combined results of interviews, environmental monitoring and simulation showed that internal climate can compromise envelope performance after the retrofit and highlighted the need to consider users in the decision making process. Ultimately, the results of this research will help to increase awareness about the potential impact of user behaviour and provide recommendations to decision makers involved in the energy retrofit of traditional structures.

Cette thèse s'intéresse à l'écoulement convectif induit par une paroi chauffante isotherme. La couche limite turbulente qui s'établit le long de celle-ci s'apparente à un panache, bien que les conditions de paroi en modifient significativement certaines caractéristiques typiques. Dans l'étude présentée, l'environnement est un milieu clos. Puisque le fluide de moindre densité s'accumule dans la partie haute de l'enceinte, une stratification en température s'établit. Afin de mieux comprendre les mécanismes qui entrent en jeu dans ce type de panache et son interaction avec le fluide ambiant, nous déployons une approche à la fois expérimentale et théorique. Sur le plan expérimental, une technique combinant Velocimétrie par Images de Particules (PIV) et Fluorescence Induite par Laser (LIF) est mise au point, et permet d'acquérir simultanément la vitesse et la température du fluide dans un plan de mesure qui couvre l'ensemble de l'écoulement. Sur le plan théorique, un modèle numérique mono-dimensionnel est développé. Il est basé sur la théorie d'entraînement de Morton et al (1956) pour la partie turbulente du panache, et tient compte de son caractère laminaire initial grâce à des solutions de similarité. Les comparaisons détaillées entre ce modèle et les résultats expérimentaux montrent les limites des modèles classiques et la pertinence des améliorations introduites. Nous évaluons notamment la contribution de la portion laminaire, et mettons en évidence le fait que le coefficient d'entraînement varie en fonction de la stratification ambiante. / This thesis focuses on the convective flow induced by a heated isotherm wall. A turbulent boundary layer develops along this wall, and resembles to a plume unlike its typical characterics are significantly modified by the boundary condition at the wall. In this study the environment is a closed box in which the lighter fluid continuously accumulates in the upper part, thus producing a temperature stratification in the interior. In order to better understand the dynamics of such a plume as well as its interaction with the ambient fluid, we deploy an approach that is both experimental and theoretical. Concerning the experiments, we developed a technique which combines Particle Image Velocimetry (PIV) with Laser Induced Fluorescence (LIF). This technique allows to simultaneously acquire the velocity and the temperature of the fluid in a plane which covers the entire flow. As concerning the theory, a one-dimensional numerical model is developed. It is based on the entrainment theory by Morton et al (1956) as for the turbulent part of the plume, and it takes into account the initial laminar character of the plume thanks to similarity solutions. The detailed comparisons between this model and the experimental results show the limits of the classical models and the relevance of the introduced improvements. In particular we evaluate the contribution of the laminar part and we highlight that the entrainment coefficient varies as a function of the ambient stratification.

Syfte: Syftet med arbetet var att utföra en jämförelse av olika isoleringsmaterial i en träbaserad väggkonstruktion genom LCA och LCC och att sedan skapa ett beslutsunderlag vid val av isoleringsmaterial. Tidigare forskning kring koldioxidutsläpp för olika byggmaterial finns. Däremot är det inte vanligt att dessa studeras tillsammans med ekonomiska aspekter. Målet med arbetet var att genomföra en LCA- och LCC-jämförelse av mineralull och andra typer av isoleringsmaterial i en träbaserad väggkonstruktion och genom resultatet skapa beslutsunderlag vid val av isoleringsmaterial. Detta bryts ner i tre frågeställningar: (1) Vilket isoleringsmaterial ger minst koldioxidbelastning med förutsättningen att tjockleken på isoleringsmaterialet ger samma u-värde i en väggkonstruktion? (2) Vilket isoleringsmaterial har lägst LCC med förutsättningen att tjockleken på isoleringsmaterialet ger samma u-värde i en väggkonstruktion? (3) Hur kan LCA- och LCC-resultat sammanvägas för att skapa beslutsunderlag för val av isoleringsmaterial? Metod: För att besvara ovan nämnda frågeställningar genomförs en litteraturstudie, fallstudie med livscykelanalys och livscykelkostnadsanalys samt dokumentanalys. Resultat: Fyra olika isoleringsmaterial i en träbaserad väggkonstruktion studerades med hänsyn till koldioxidutsläpp och livscykelkostnader. Materialåtgång och u-värde beräknades för väggkonstruktionen. Funktionell enhet för analyserna är 1 kvadratmeter av väggkonstruktionen med ett u-värde på först 0,164 W/m2K och sedan 0,106 W/m2K. Det material som leder till lägst koldioxidutsläpp för väggkonstruktionen är i första hand cellulosa och därefter träfiber, mineralull och sist polyuretan. Det material som leder till lägst kostnader för väggkonstruktionen är i första hand mineralull, cellulosa, träfiber och sist polyuretan. Konsekvenser: Arbetet visar att val av isoleringsmaterial kan sänka koldioxidutsläpp under produktionsfasen utan att medföra höga kostnader. Det visar även att val av isoleringsmaterial blir än mer relevant när energisnåla byggnader ska produceras där u-värde för väggkonstruktionen ligger runt 0,11 W/m2K då detta innebär större isoleringstjocklekar totalt för väggen. För att minska koldioxidutsläpp utan att nämnvärt höja kostnaden bör organiska isoleringsmaterial väljas. Begränsningar: Arbetet behandlar ej klimatpåverkan från husets energi- eller uppvärmningssystem. För att få samma förutsättningar för de valda isoleringsmaterialen måste samma u-värden i väggkonstruktionen uppnås. Arbetet avser hela livscykeln från vagga till grav i en LCA och LCC, dock har utsläpp genererade av transport utelämnats i analyserna. Enbart de termiska och miljömässiga egenskaperna hos isoleringsmaterialen kommer att beaktas. I fallstudien beaktas en träbaserad yttervägg av ett flerbostadshus med trästomme. / Purpose: The aim of this thesis is to perform a comparison of different insulation materials in a wood-based wall structure through LCA and LCC analysis, and then tocreate a decision base for the selection of insulation material. Previous research oncarbon dioxide emissions for various building materials has been done. On the otherhand, it is not common for these to be studied together with economic aspects. The aimof the work is to perform an LCA and LCC comparison of mineral wool and other types of insulation material in a wood-based wall structure and through the result create decision basis in the selection of insulation material. This is investigated by three questions: (1) Which insulation material emits the lowest amount CO2-equivalents, considering that the thickness of the insulation material has the same u-value in a wall structure? (2) Which insulation material leads to lowest LCC, considering that the thickness of the insulation material gives the same u-value in a wall structure? (3) How can LCA and LCC results together create decision bases for choosing insulation materials? Method: In order to answer the above questions a literature study, case study with lifecycle analysis and life cycle cost analysis and document analysis is conducted. Findings: Four different insulation materials in a wood-based wall structure were studied concerning carbon dioxide emissions and life cycle costs. Material utilization and u-value were calculated for the wall structure. Functional unit for the analyses is 1 square meter of the wall structure with a u-value of 0.166 W/m2K and 0.107 W/m2K. The material that leads to the lowest carbon dioxide emissions for the wall structure is cellulose, wood fibre, mineral wool and lastly polyurethane. The material that leads tothe lowest cost of the wall structure is mineral wool, cellulose, wood fibre and lastly polyurethane. Implications: The work shows that the choice of insulation materials can reduce carbondioxide emissions during the production phase without incurring excessive costs. It alsoshows that the choice of insulation materials becomes even more relevant when energy efficient buildings are to be produced where the u-value of the wall structure is around 0.11 W/m2K, as this means larger insulation thicknesses in total for the wall. In orderto reduce CO2 emissions without significantly increasing costs, organic insulation materials should be chosen. Limitations: The work does not address climate impact from the house's energy or heating system. To get the same conditions for the selected insulation materials, thesame u-values in the wall structure must be achieved. The work concerns the entire lifecycle from cradle to grave in an LCA and LCC, however, emissions generated bytransport have been omitted in the analyses. Only the thermal and environmental properties of the insulation materials are treated. The case study considers a wood-based exterior wall of a multi-story building.

Träbyggande har stark historisk förankring i Sverige. För drygt ett sekel sedan sattes ett förbud in mot att bygga hus i fler än två våningar i trä på grund av den ansedda brandrisken materialet medförde. Vid Sveriges inträdande i EU år 1994 togs det gamla beslutet bort och utvecklingen inom träbyggandet för flerbostadshus har därefter fått en rejäl uppgång. Utvecklingen har medfört ett modernare sätt att bygga, från att tidigare ha byggt allt på byggarbetsplatsen till montage av prefabricerade väggmoduler. Med detta tillvägagångssätt har byggandet både kunnat säkra en högre kvalitet samt effektiviserats.  Ett företag som arbetar med prefabricerade väggblock är Isotimber. Deras väggblock är unik på det sätt att de endast innehåller trä, för att uppnå ett högre isolervärde har råvaran trä kombinerats med urfrästa luftspalter. Isotimber har haft en önskan att utveckla sin produkt eftersom de fastskruvade kassetterna som bildar ett enhetligt väggblock separerar vid lyft. Lyftpunkterna har placerats genom borrade hål i väggblocken med genomförda lyftstroppar, ett tillvägagångssätt som Isotimber önskat förändra. Tvärkrafterna som uppstått vid lyften har verkat diagonalt mot väggblocken och antal lyftpunkter har varierat.  Studien har riktat sig mot att utveckla det befintliga väggblocket samt studera om lyft har gått att utföra på ett annat sätt än i dagsläget. Lyftpunkternas placering har även granskats.  Resultatet av produktutvecklingen har lett till att en limträbalk har placerats i överkant av blocken. Det har medfört att lyftpunkter har förflyttats till limträbalken där håltagning för stroppbanden kommer att utföras. Antal lyftpunkter har blivit beroende av väggblockens spännvidd och de tvärkrafter som uppstår vid lyft skall inverka vertikalt mot väggblocken. Resultatet av den nya väggblocksprototypen har krävt dimensionering av limträbalk vid lyftpunkter samt infästningarna mellan väggblock och limträbalk.  Väggblockets förändringar har bidragit till ett smidigare montagesystem. Den monterade limträbalken kan även anses ge en mindre nedböjning i väggblocket. Lyftpunkterna har blivit fler med bestämda avståndsintervall för att motverka separationer mellan de ihopskruvade kassetterna i väggblocken. / Building with   wood has a strong historical anchorage in Sweden. Just over a century ago, a   ban was imposed on building houses on more than two floors of wood due to the   perceived fire risk caused by the material. At Sweden's accession to the EU   in 1994, the old decision was removed and the trend in the construction of   wooden houses for multi-family houses has subsequently increased   dramatically. The development has resulted in a more modern way of building,   from building everything on the construction site to the assembly of   prefabricated wall modules. With this approach, construction has been able to   ensure a higher quality and efficiency.  A company that   works with prefabricated wall blocks is Isotimber. Their wall blocks are   unique in that they contain only wood, in order to achieve a higher   insulation value, the raw material wood has been combined with milled gaps of   air. Isotimber has had the desire to develop its product because the screwed   cassettes that forms a uniform wall block, separates during the lifts. The   lifting points have been placed through drilled holes in the wall blocks with   inserted lifting straps, an approach that Isotimber wishes to change. The   transverse forces that have occurred during the lift have acted diagonally   against the wall blocks and the number of lifting points has varied.  The study has   been aimed at developing the existing wall block and to study whether lifting   could be done in a different way than today. The position of the lifting   points has also been examined.  The result of   product development has led to a laminated wooden beam being placed above the   blocks. This has meant that lifting points have been moved to the laminated   wooden beam where perforation for the straps will be executed. The number of   lifting points has become dependent on the width of the wall blocks, and the   transverse forces that arise during lifting must be vertical to the wall   blocks. The result of the new wall-block prototype has led to dimensioning of   the laminated wooden beam at the lifting points, as well as the connections   between the wall block and the laminated wooden beam.  The wall block   changes have contributed to a smoother mounting system. The laminated wooden   beam can also be considered to give a smaller deflection in the wall block.   The lifting points have become more at fixed range intervals to counter the   separations between the screwed cassettes in the wall blocks. / <p>Betyg 170707, H14.</p>

This research paper studied the first two weeks after President Donald Trump allegedly called African countries “shithole countries” in a bi-partisan meeting on immigration. It explored the frames and emerging themes used by the media when covering the incident and the surrounding issues. Using the framing theory as a theoretical framework, the study examined the six identified news frames through qualitative content analysis. The six frames used in the coverage of the “shithole countries” incident are racial, conflict, consequences, morality, human interest, and policy. The study examined articles from four news sources that lean liberal, conservative, central-liberal, and central conservative. The study indicated that the four news sources all used five of the six frames, as the Wall Street Journal did not use the morality frame at all. The most used frame was the human interest frame, followed by conflict and consequences. The New York Times and the Wall Street Journal used the conflict frame the most. And CNN and FOX used the consequences frame the most.

Lors du procédé de cokéfaction, en raison de la faible largeur de la chambre de carbonisation des fours modernes, l’expansion horizontale de la pâte à coke génère une poussée sur les parois de chauffage. L’objectif de cette thèse, qui s’inscrit dans le cadre du projet européen « Swelling Pressure in a Coke Oven, Transmission on Oven walls », est de mieux comprendre le phénomène de poussée des charbons lors de la cokéfaction et de développer un modèle permettant d’anticiper ce phénomène. Pour cela, un modèle phénoménologique prenant en compte les phénomènes physico-chimiques en présence a été développé. Une mise en équation originale est proposée pour la cinétique de condensation des goudrons et le gonflement des grains de charbon lors de la pyrolyse. Le modèle proposé est le premier reproduisant simultanément la poussée sur les piédroits et la pression des gaz produits lors de la cokéfaction. Les résultats de simulation du cas particulier de la cokéfaction du charbon Blue Creek dans le four pilote du Centre de Pyrolyse de Marienau et les mesures de pression, de température et de poussée réalisées lors des essais présentent des écarts mais demeurent en bon accord. Ces écarts sont essentiellement dus à la méconnaissance des propriétés du charbon et de son comportement mécanique. L’hypothèse d’un comportement élastique linéaire entraîne une surestimation de la poussée. L’étude de sensibilité amène, entre autres, à la conclusion que la poussée ne dépend pas directement de la pression des gaz et que le gonflement des grains de charbon joue un rôle déterminant. / During the coking process, due to the small width of the carbonization chamber of modern ovens, horizontal expansion of coal generates a pressure on the oven walls. The objective of this thesis, which is part of European project « Swelling Pressure in a Coke Oven, Transmission on Oven walls », is to better understand the wall pressure phenomenon during coking process and to develop a model which can permit to anticipate this phenomenon. For this, a phenomenological model which takes into account the physical chemistry phenomena in presence is developed. An original implementation is proposed for the kinetic of tars condensation and the coal swelling during pyrolysis. The proposed model is the first which reproducing simultaneously the wall pressure and the gas pressure during coking process. The simulation results of coking process of the specific case of Blue Creek coal in the pilot oven of Centre de Pyrolyse de Marienau and the measurements of gas pressure, of temperature and of wall pressure performed during the tests have discrepancies but remain in good agreement. The discrepancies are mainly due to the ignorance of coal properties and its mechanical behavior. The assumption of linear elastic behavior leads to wall pressure overestimation. The sensitivity study permits to conclude that the wall pressure is not directly dependant to the gas pressure and that coal swelling play a causal role.

Este estudo tem como objetivo analisar os comportamentos hidráulico, mecânico e microestrutural de misturas compostas, por solo residual arenito Botucatu e bentonita sódica, com e sem adição de cimento, quando permeadas por água (H2O), soda cáustica (NaOH), na concentração de 5% e ácido sulfúrico (H2SO4) na mesma concentração para sua possível utilização em barreiras de contenção de contaminantes do tipo slurry wall. O arenito, solo areno-siltoso característico da região de São Leopoldo/ RS, compõe a matriz das misturas, sendo que a bentonita sódica confere a estas características impermeabilizantes, imprescindíveis às barreiras hidráulicas de contenção. O cimento, além de fazer com que a mistura adquira resistência, interfere na reatividade da barreira, mediante os contaminantes utilizados. A estimativa da eficiência destas misturas baseou-se na comparação entre os valores do coeficiente de condutividade hidráulica, resistência à compressão simples e parâmetros de compressibilidade determinados através dos ensaios de compressão confinada, apresentados nos ensaios com e sem contaminação, conjuntamente com a análise microestrutural das misturas nas mesmas situações. Foram feitas análises químicas por Difração de Raios-x, Microscopia Eletrônica de Varredura (SEM) e Análise Química Elementar (EDS) visando à explicação ordinária das causas microestruturais que levam as misturas a determinado comportamento sob percolação de contaminantes. Na busca do efeito de cada componente sobre o comportamento final de determinada mistura, houve a necessidade de realizar análises químicas e microscópicas individuais, também sob interferência ou não de substâncias agressivas. A partir deste estudo foi possível inferir que a mistura solo-cimentobentonita, é adequada à utilização como barreira vertical quando o contaminante for ácido sulfúrico, por no mínimo 20 semanas, já que a eficiência da mesma foi comprovada pela realização de ensaios no permeâmetro de parede rígida, considerado adequado para este tipo. O uso da mistura solo bentonita para barreiras verticais pode ser emergencial visto que quando o contaminante for soda cáustica a mistura resiste por 4 dias. / The objective of this study is to analyze the hydraulic, mechanical and micro-structural conduct of composite mixtures of Botucatu residual soil and sodic bentonite, with and without cement addition, when permeated by water (H2O), caustic soda (NaOH) in a concentration of 5% and sulfuric acid in the same concentration to their possible utilization in contention of contaminant barriers of the slurry walls type. The sandy soil constitutes part of the matrix of the mixtures. The sodic bentonite confers to these mixture essential waterproof characteristics of hydraulic barriers of containment. The cement interferes on the barrier reactivity moreover add resistance to the mixture by the contaminants that were utilized. The efficiency estimation of these mixtures was established by comparison between hydraulic conductive coefficient, unconfined compression strength and one dimensional compressibility presented on the tests with or without contamination, with the mixture micro-structural and chemical analysis on the same situations: X-ray diffraction, scanning electronic microscopy, Elemental Chemical Analysis (EDS), they want to explain the micro-structural causes that make the mixtures to determinate behavior by percolating of contaminants. Searching the effect of all components about the final behavior of determined mixture there was the necessity to carry out chemical and microscopically individual analysis also by aggressive or non-aggressive substances interference. After completed the study, it is possible to affirm that the soil-cement-bentonite mixture, is good for using as a vertical barrier when the contaminant is sulfuric acid, based on the results of rigid wall permeameter, adequate for this kind of mixture. The use of soilbentonite mixture as vertical barrier for caustic soda could be done just in emergency cases and for a short period of time, once that after some time the barrier reduces drastically its efficiency.

A partir da minha produção de fotografias da série Paredes, este estudo investiga a representação de paredes brancas e relaciona as imagens produzidas com as reflexões dos teóricos contemporâneos de arte Hanneke Grootenboer, sobre fundos de naturezas-mortas da Holanda seiscentista, e Georges Didi-Huberman, sobre a representação de paredes em alguns afrescos de Fra Angelico. As interpretações de ambos apontam como tais imagens de paredes, usualmente encontradas em fundos pictóricos, podem ser consideradas como áreas onde há a ocorrência de algo que excede a representação. A série Paredes propõe a análise de imagens que qualificamos como rarefeitas e neutras com a intenção de verificar se elas apresentam ou evocam algo diverso da cena fotografada, como o vazio proposto por Grootenboer ou o infinito divino sugerido por Didi-Huberman em imagens similares. Ao utilizar o conceito de “neutro” de Roland Barthes, podemos situar essas imagens, por serem representações de superfícies inexpressivas e sem importância, em um campo de oscilação no qual elas não aderem a nenhuma posição fixa quanto à definição de seu conteúdo. A condição de deriva – inerente ao neutro – que as imagens de parede carregam as tornam potências com capacidade de suscitar quaisquer ideias, inclusive opostas e extraordinárias, como as de vazio e de infinito. / This study is based on my photographic work the Paredes series and investigates the representation of white walls, relating the images to the work of the contemporary art theorists Hanneke Grootenboer and Georges Didi-Huberman, the former reflecting on the backgrounds of 17th-century Dutch still-life painting and the latter considering the representation of walls in some of Fra Angelico’s frescos. Their interpretations indicate how such images of walls usually found in the backgrounds of paintings might be considered as areas where something occurs that goes beyond representation. The Paredes series proposes an analysis of images that we consider neutral or less dense, with the aim of testing whether they present or evoke something other than the photographic scene, such as the void proposed by Grootenboer or the divine infinity suggested by Didi-Huberman in similar images. By employing Roland Barthes’s concept of the “neutral” we might, due to their being representations of inexpressive surfaces of no importance, situate these images in a field of fluctuation, in which they adopt no fixed position in terms of definition of content. The condition of drift – inherent to the neutral – contained in the images of walls, gives them potential to support any idea, including contrasting and exceptional ones such as the void and infinity.