Global ETD Search

1	Formation of proteins and glycoproteins during aggregation and development of Dictyostelium Crandall, I. January 1987 (has links) No description available. 572 Slime mould growth cycle
2	Método para redução de mancha nas vedações externas de edifícios. / Method to reduce soiling deposition on building envelope. Maranhão, Flávio Leal 11 December 2009 (has links) O permanente contato das vedações externas dos edifícios com os materiais integrantes das vedações externas dos edifícios (fachadas e telhados) com os agentes de degradação provocam o surgimento de manchas, que normalmente estão associadas à deposição de poluentes e a proliferação de microorganismos. Para inibir o surgimento dessas manchas existem, atualmente, diversos métodos disponíveis, sendo que nenhum tem se mostrado efetivo. Esta tese de doutorado, com base em um extenso programa laboratorial - com o uso de métodos como MEV, FTIR, ângulo de contato, crescimento acelerado de microrganismos, atividade fotocatalítica, entre outros-, criou um novo método, destinado aos materiais de construção silicosos e porosos, que se baseia na modificação de suas propriedades superficiais, por meio da sobreposição de uma camada hidrofóbica por uma hidrofílica. Para se obter essa disposição superficial, utilizou-se um hidrofugante à de octil-silicone, que apresenta elevada repelência à água e maior durabilidade, e um semicondutor à base de dióxido de titânio, que apresenta atividade fotocatalítica quando incidido por radiação ultravioleta. Como resultado, o método proposto (denominado na tese por WR+TiO2-sequencial) apresenta, comprovadamente, os seguintes benefícios: (i) redução de manchas causadas pela adesão de partículas com características apolares, similares às partículas de poluição dos grandes centros urbanos; (ii) limpeza espontânea de certos tipos de manchas, decorrentes dos processos fotocatalíticos que promovem a oxidação/redução de matéria orgânica; (iii) inibição do crescimento de microrganismo em escala laboratorial; (iv) redução da absorção total de água e, principalmente, da cinética do ganho de massa. Por isso, edificações cujas vedações externas venham a ser tratadas com o método aqui proposto são, potencialmente, células ativas para a sustentabilidade do ambiente construído, pois: reduzem o consumo de energia, reduz os custos de manutenção e contribuem para despoluição da atmosfera urbana. / Building roofs and façades usually show blackening surfaces after few years in large cities. On porous and silicious materials those soiling is caused by particles pollution depositions and mould growth, and the available methods available to prevent this phenomenum do not have a good performance along its service life. This thesis, based on an intensive laboratory research with many test technics as SEM, FTIR, contact angle, accelerated mould growth, and photocatalytical activity, create a new method to prevent soiling on porous and silicous building materials. This method modify the materials surface properties, making the outer surface layers with nano-actived titanium dioxide particles, which has photocatalitycal activity under UV radiation, and below it a hydrophobic layer, composed by octyl-silicones. The main results in laboratory scale experiments obtained by this new method (so-called in this thesis by WR+TiO2-sequencial) are: (i) stainings reductions caused by apolar agent, (ii) self-cleaning properties for some stain and after UV radiation exposition, (iii) mould growth resistance, and (iv) water absorption reduction. As a consequences, building envelopes trated with the new method is supposed to contribute to built and environment sustantability, because: can reduce the energy consumption, reduce de maintenance costs e has a de-pollution properties. Building envelope Fachada Fungos Mould growth Pollution deposition Poluição atmosférica Revestimento de superfície Surface treatment
3	Minimising energy use and mould growth risk in tropical hospitals Zainal Abidin, Abdul Murad January 2012 (has links) Critical areas in a hospital, such as Intensive Care Units (ICUs) and isolation rooms, are designed to strict health standards. More often than not, these areas operate continuously to maintain designed indoor conditions in order to ensure the safety of patients, making them energy intensive areas. Several attempts have been made to design them to be more energy-efficient. However, cases have emerged in hot and humid countries like Malaysia where combination of poor design, operation and maintenance practices, exacerbated by the humid outdoor conditions especially during night time, have led to occurrences of mould growth in these critical areas. A question arise whether energy efficient design of a critical area can be achieved without incurring a risk of mould growth due to factors like moisture transfer, or continuous part load operation of HVAC systems. The objective of research in this thesis is to investigate the trade-off between optimizing the building and HVAC systems and minimizing the risk of mould growth in hospital buildings located in hot and humid climates. The problem formulation is a single zone isolation room with dimensions based from a real-life isolation room of a district hospital in Malaysia. The design variables, namely HVAC systems and the details of building constructions were selected as input files for energy performance evaluation using EnergyPlus. The output from the simulation will be compared with the selected existing mould growth model during post processing to determine the optimum solution. Simulation and the generation of solutions will be repeated until the most optimum solution is achieved. A binary-encoded Genetic Algorithm (GA) was used as an approach to the minimisation of hospital building energy use. The GA is proven to be effective in performing multi-objective optimisation, since the objective functions for this research are more than one; namely, the minimum annual energy use in the isolation room and the critical indoor surface conditions, such as temperature and relative humidity, below which there would be no mould growth. The research has shown that the normal practice of isolation room design for Malaysian hospitals does not work in minimising energy use and minimising the risk of mould growth and a new design guideline for isolation rooms in Malaysia is recommended. The principal originality of the research will be the application of optimisation methods to investigate the relationship, or trade-off between energy use and the risk of mould growth, particularly for hospital buildings in a hot and humid climate. In this respect, the new knowledge will be on the optimisation procedure and required modelling/analysis components. This combinatorial approach would serve as decision making tool for building and HVAC systems designers in designing more energy-efficient overall environment systems in hospitals, with particular attention to critical areas that are operating continuously. 624.1
4	Houses with mould problems : Comparison of two methods for verifying mould growth in buildings Takkinen, Johanna January 2005 (has links) During the last ten years, the adverse health effects in upper respiratory system and irritation symptoms have become increasingly evident in residents living in moisture damaged houses with dampness and mould growth. In the mid of 1995, Finnish environmental health authorities faced the problem with an increasing demand for investigations to verify the microbial growth in suspected buildings and thereby taking appropriate control measures to protect the health of occupants. As an extension of an earlier relatively onerous method for quantification of microbial growth on surfaces, the Food Laboratory in Porvoo developed an applied direct streak method (DSM) aiming at a facilitation of the method verifying the presence of mould growth. The method was established in close collaboration with health inspectors. The DSM was compared to the original culture method (CM) and repeatability and reproducibility were good or very good. The DSM is a semi-quantitative method and enables the health inspectors to take surface samples without breaking the building structures and without being restricted to stiff surfaces. The results can demonstrate that the material is damaged by active viable mould growth. The DSM provides a powerful and useful tool for health inspectors to verify mould growth in buildings and it supports them to make decisions that are needed to protect the health of occupants. The cost of DSM is about one fourth of that of the more elaborate CM. The DSM is being increasingly used in Finland. / <p>ISBN 91-7997-123-7</p> Indoor Air Mould Growth Laboratory Method Mycoecology Public health science Folkhälsovetenskap
5	Método para redução de mancha nas vedações externas de edifícios. / Method to reduce soiling deposition on building envelope. Flávio Leal Maranhão 11 December 2009 (has links) O permanente contato das vedações externas dos edifícios com os materiais integrantes das vedações externas dos edifícios (fachadas e telhados) com os agentes de degradação provocam o surgimento de manchas, que normalmente estão associadas à deposição de poluentes e a proliferação de microorganismos. Para inibir o surgimento dessas manchas existem, atualmente, diversos métodos disponíveis, sendo que nenhum tem se mostrado efetivo. Esta tese de doutorado, com base em um extenso programa laboratorial - com o uso de métodos como MEV, FTIR, ângulo de contato, crescimento acelerado de microrganismos, atividade fotocatalítica, entre outros-, criou um novo método, destinado aos materiais de construção silicosos e porosos, que se baseia na modificação de suas propriedades superficiais, por meio da sobreposição de uma camada hidrofóbica por uma hidrofílica. Para se obter essa disposição superficial, utilizou-se um hidrofugante à de octil-silicone, que apresenta elevada repelência à água e maior durabilidade, e um semicondutor à base de dióxido de titânio, que apresenta atividade fotocatalítica quando incidido por radiação ultravioleta. Como resultado, o método proposto (denominado na tese por WR+TiO2-sequencial) apresenta, comprovadamente, os seguintes benefícios: (i) redução de manchas causadas pela adesão de partículas com características apolares, similares às partículas de poluição dos grandes centros urbanos; (ii) limpeza espontânea de certos tipos de manchas, decorrentes dos processos fotocatalíticos que promovem a oxidação/redução de matéria orgânica; (iii) inibição do crescimento de microrganismo em escala laboratorial; (iv) redução da absorção total de água e, principalmente, da cinética do ganho de massa. Por isso, edificações cujas vedações externas venham a ser tratadas com o método aqui proposto são, potencialmente, células ativas para a sustentabilidade do ambiente construído, pois: reduzem o consumo de energia, reduz os custos de manutenção e contribuem para despoluição da atmosfera urbana. / Building roofs and façades usually show blackening surfaces after few years in large cities. On porous and silicious materials those soiling is caused by particles pollution depositions and mould growth, and the available methods available to prevent this phenomenum do not have a good performance along its service life. This thesis, based on an intensive laboratory research with many test technics as SEM, FTIR, contact angle, accelerated mould growth, and photocatalytical activity, create a new method to prevent soiling on porous and silicous building materials. This method modify the materials surface properties, making the outer surface layers with nano-actived titanium dioxide particles, which has photocatalitycal activity under UV radiation, and below it a hydrophobic layer, composed by octyl-silicones. The main results in laboratory scale experiments obtained by this new method (so-called in this thesis by WR+TiO2-sequencial) are: (i) stainings reductions caused by apolar agent, (ii) self-cleaning properties for some stain and after UV radiation exposition, (iii) mould growth resistance, and (iv) water absorption reduction. As a consequences, building envelopes trated with the new method is supposed to contribute to built and environment sustantability, because: can reduce the energy consumption, reduce de maintenance costs e has a de-pollution properties. Fachada Fungos Poluição atmosférica Revestimento de superfície Building envelope Mould growth Pollution deposition Surface treatment
6	Yttervägg av trä utan invändig diffusionsbarriär : En byggnadsfysikalisk studie av en stuga Vaa, Kristian Huustad January 2018 (has links) Trä har byggnadsfysikaliska egenskaper som skiljer det från en del andra material som traditionellt har blivit använda som bärande delar vid byggen. Träets hygroskopiska egenskaper och låga egenvikt ger andra användningsområden än till exempel betong eller stål. Dess låga egenvikt ger också spännande konstruktionsmässiga möjligheter och kan göra det möjligt att bygga på platser som annars inte är tillgängliga utan användning av mer avancerande tekniker och transportmetoder. I denna rapport har en del av ytterväggen till en stuga undersökts med avsikt att bedöma huruvida det i väggkonstruktionen kommer uppstå problem med mögelangrepp. Den undersökta delen av väggen ligger tre meter under marknivå. Väggen är konstruerad med en ångspärr mot marken och med ett en meter tjockt lager cellglasgrus mot denna. Innanför cellglasgruset är det en geotextil, 2 x 100 mm träfiberisolering samt 93 mm vertikalt timrat limträtimmer vilket också utgör ytskiktet på invändig sida. Undersökningen utfördes som en analys av en simulering som blev genomförd med mjukvaran WUFI® Pro 6.1. Resultaten av analysen var kvantitativa data i form av grafer och diagram. Resultatet av simuleringen visade att det inte kommer uppstå problem med mögel i konstruktionen. Dock är träets fuktbuffrande egenskaper tydliga och det anses generellt viktigt att se till att material har en inbyggnadsfukthalt som är under det som är gynnsamt för växt av mögel. / Wood has physical properties that makes it different from most other materials that traditionally has been used as load bearing parts when constructing a building. The hygroscopic properties and low relative weight of wood makes room for a different field of application than what is the case with for instance concrete or steel. Its low relative weight also gives interesting constructional possibilities and can make it possible to build on sites otherwise inaccessible without advanced techniques and means of transport. In this report the lower part of an exterior wall in a mountain cabin has been studied. The purpose of the study has been to examine whether the cabin will have problems related to mould or fungus. The examined part of the wall lies three meters below ground level. It is constructed with a steam barrier towards the ground, and a one meter thick layer of foam glass fragments on the inside of this. Further towards the inside of the wall there is a geotextile, two layers of 100 mm wood fibre insulation and one layer of 93 mm thick laminated vertically timbered timber, which faces the inside of the cabin. The examination was performed as an analysis of a simulation made with the software WUFI® Pro 6.1. The results of the analysis were quantitative data in the form of graphs and diagrams that were easily assessed against relevant literature. The results from the simulation showed that the construction would not have any problems related mould or fungus. However, the moisture buffering properties of the wood are obvious, and it is generally considered important that materials have a built-in moisture that is below what is favourable for mould or fungus growth. / <p>Betyg 2019-06-05</p> Mould Mould growth Mould models Wood WUFI Exterior wall Mögel Mögelpåväxt Mögelmodeller Trä WUFI Yttervägg Civil Engineering Samhällsbyggnadsteknik
7	Mould resistance design for external wood frame wall systems : Simulation and evaluation of wall structures under varying conditions of exposure using the MRD model / Mögelresistensdimensionering för träregelkonstruktioner i ytterväggar : Simulering och utvärdering av ytterväggar under varierande exponeringsförhållanden med MRD-modellen Dahlström, Carl, Giesen, Emma January 2015 (has links) Moisture induced damages to building envelopes can result in microbial growth possibly affecting the health and wellbeing of occupants. Recent failing structures and damaged buildings indicate a lack of tools to estimate risk of mould growth and moisture damage. In this work a so-called mould resistance design (MRD) model has been applied for mapping the risk for mould growth on a number of wood-containing wall structures. The MRD model introduces an engineering approach to moisture safety design in a similar way as for structural design, where load and resistance is compared. The MRD model introduces and quantifies the concepts of climatic exposure and material resistance and compares them through an MRD index. This MRD index incorporates a limit state, which gives the critical dose of exposure for a given resistance to initiate onset of mould growth. Three conceptual wall structures were evaluated and analyzed in terms of MRD index: two wall systems with an air gap and one wall system without. A parametric study investigating the effect of parameter variation on MRD index was conducted. Evaluated parameters were: climate (geographic location), orientation, air changes per hour in the air gap, driving rain penetrating the facade layer, exterior plaster properties and wood type. The simulations were performed using the hygrothermal calculation software WUFI. The results indicate that the wall systems with a ventilated air gap performs better in terms of MRD index i.e. suggests a lower risk of initiation of mould growth than the wall system without air gap. The results of orientation variation show that wall systems perform differently dependent on layering structure. The inherent water sorption properties of the exterior plaster are shown to have a large effect on the results. In addition, uncertainties were found on how to accurately include hydrophobicity as a parameter in the model. The report concludes that geographical location and its specific climate is the most important parameter to consider when designing for moisture safety. The MRD model is recommended to be used in combination with traditional moisture safety evaluation. MRD Mould growth Wood frame wall systems Moisture safety evaluation WUFI MRD Mögel Träregelväggar Fuktsäkerhetsprojektering WUFI Building Technologies Husbyggnad Materials Engineering Materialteknik
8	Optimalizace návrhu moderních nízkoenergetických dřevostaveb / Optimizing the design of modern low-energy wooden houses Vahalová, Eva January 2017 (has links) The main aim of the thesis was focused on hygrothermal simulation of critical details of two prefabricated wooden buildings - especially connections of the perimeter wall to monolithic foundations, respectively with waterproofing layer. The composition of the external walls of these selected buildings has quite different compositions and thus different potentials of drying integrated moisture from the components. Practical measurement of moisture weight-content was applied to the wooden bottom plate, which is in direct contact with the concrete slab structures. The influence of different design solutions on hygrothermal characteristics of the wooden plate was examined with regards to the risk of mould growth, analysis of mass loss due to the decay fungi and with the aim to estimate the durability of the studied details of prefabricated wooden houses. The subsequent research focused on the differences in physical and mechanical properties of natural spruce wood (Untreated, (-), A) and impregnated spruce (Treated, (+), B) using supercritical CO2 and its possible impact on wood protection for mould growth. Samples of identical Untreated and Treated spruce were collected in the laboratory and subjected to thermal and hygrothermal experiments. The comparison of the resulting values of the individual experiments is presented. Required values needed for numerical calculations were obtained from these experiments. In conclusion, the summary of founded comparison is presented. The mould growth analysis and its influence on the durability of wooden structures offer a view of the behaviour of the structures. Relevant findings and recommendations for the future praxis are mentioned.
9	Fuktkontroll av en ventilerad platta på mark : Modellering i COMSOL Multiphysics 5.5 Liljestrand, Simon, Lundell, Viktor January 2020 (has links) Krypgrunder i någon form har använts som grundkonstruktion i Sverige under långtid. Förr var det torpargrunder som med tiden blev isolerade krypgrunder och plintgrunder. Gemensamt för krypgrundskonstruktioner som är ventilerade med utomhusluft är att under sommarhalvåret blir det förhöjda relativa ånghalter. Syftet med fallstudien är att studera en uteluftsventilerad konstruktion med välisolerat bjälklag och markisolering. Konstruktionen är nedgrävd och ventilationen i grunden sker via en tunn spalt under marknivå. Luftspaltens temperatur och relativa ånghalt är av intresse för att avgöra om det finns risken för mögel i konstruktionen. En simulering av värmeflödet mellan byggnad och mark genomförs i COMSOLMultiphysics 5.5 för att avgöra temperaturfördelningen i konstruktionen. Temperaturfördelningen ligger som grund för fastställandet av relativ ånghalt i konstruktionens luftspalt. Simuleringen använder klimatdata för ett typår i Gävle. Simuleringen visar att det är höga temperaturer i luftspalten året runt. Detta ger enrelativ ånghalt som månadsmedel på 37–77% under ett år. Den höga temperaturen iluftspalten bidrar till att hålla konstruktionen torr då kritisk relativ ånghalt, 75–80%, inte överstigs under en längre period. Resultat är förvånansvärt positivt med en låg risk för mögeltillväxt i konstruktionen.Det finns många antaganden framförallt vilket luftflöde som återfinns i luftspalten.För att validera resultaten i arbetet så bör mätningar genomföras på de två prototyphus som existerar. / Crawl spaces in some form have been used as foundations in Sweden for a long time.In the past, it was uninsulated crawl spaces that eventually evolved into insulatedcrawl spaces and open plinth foundations. An increased relative humidity during thesummer is a common problem for crawl spaces that are ventilated with outdoor air. The purpose of the case study is to study an outdoor ventilated structure with wellinsulated floor and ground insulation. The construction is below ground level andthe ventilation takes place via a thin air gap below ground level. The temperatureand relative humidity in the air gap are of interest to determine if there is a risk ofmould growth in the design. A simulation of the heat flow between the building and the ground is carried out inCOMSOL Multiphysics 5.5 to determine the temperature distribution in the design.The temperature distribution is the basis for the determination of relative vaporcontent in the air gap of the structure.The simulation uses climate data for a typicalyear in Gävle. The simulation shows a high temperature in the air gap which gives a relative vaporcontent as a monthly average of 37–77% during a year. The high temperature in theair gap contributes to keeping the structure dry when critical relative humidity, 75–80%, is not exceeded for a longer period of time. The results are surprisingly positive with a low risk of mold growth in the construction.There are many assumptions, in particular, which airflow is found in the airgap. In order to validate the results in the work, measurements should be made onthe two prototype houses that exist. COMSOL COMSOL multiphysics Crawlspace Suspended foundation Crawler space Crawling space Mould Mould growth Moisture Moisture balance Ventilated slab on ground VPM Building technology Lundell Liljestrand Ljubos Ljusbo hyreshus Ljusbo hyreshus AB Air gap Moisture content Relative moisture content critical relative moisture content foundation COMSOL COMSOL multiphysics Krypgrund Torpargrund Mögel Fuktbalans Fuktteori Mögeltillväxt Ventilerad platta på mark VPM Byggnadsingenjör Byggnadsteknik Liljestrand Lundell Ljusbo hyreshus Ljusbo Ljusbo hyreshus AB Luftspalt Fukthalt Relativ ånghalt Ånghalt Kritisk relativ ånghalt grundläggning Building Technologies Husbyggnad

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