Processing and testing of reinforced PA66 based composites

The new requirements in different sectors, such as aerospace, automotive and construction, for lightweight materials have led to an increase in demand for composite materials suitable for use in high rate production processes, such as plastic injection. This makes it necessary to look for matrices and reinforcements that, in addition to being compatible with each other, are also compatible with the injection process. It is in this area of research where the work presented here arises. To meet the two requirements mentioned above, this study contemplates a battery of composite materials obtained by combining PA66 and fiberglass, in different proportions and configuration, both for the preparation of the matrix and for reinforcement. For the elaboration of the matrix, two options have been evaluated, PA66 and PA66 reinforced at 35% with short glass fibre. To obtain reinforcement, six different options have been evaluated; two conventional fiberglass fabrics (each with different density) and four hybrid fabrics obtained from the previous ones by adding PA66 in different configurations (two over-stitched fabrics and two other fabrics). The different composite materials obtained were validated by means of the corresponding adhesion, peeling and resistance tests.Xunta de Galicia | Ref. 046_IN848D_2020_112386

A comparison study into low leak rate buoyant gas dispersion in a small fuel cell enclosure using plain and louvre vent passive ventilation schemes

Hydrogen, producing electricity in fuel cells, is a versatile energy source, but with risks associated with flammability. Fuel cells use enclosures for protection which need ventilating to remove hydrogen emitted during normal operation or from supply system leaks. Passive ventilation, using buoyancy driven flow is preferred to mechanical systems. Performance depends upon vent design, size, shape, position and number. Vents are usually plain rectangular openings, but environmentally situated enclosures use louvres for protection. The effect of louvres on passive ventilation is not clear and has therefore been examined in this paper. Comparison ‘same opening area’ louvre and plain vent tests were undertaken using a 0.144 m3 enclosure with opposing upper and lower vents and helium leaking from a 4 mm nozzle on the base at rates from 1 to 10 lpm, simulating a hydrogen leak. Louvres increased stratified level helium concentrations by typically in excess of 15 %. The empirical data obtained was also used in a validation exercise with a SolidWorks: Flow Simulation CFD model, which provided a good qualitative representation of flow behaviour and close empirical data correlations

Determining Safety Parameters for Small Scale Passive Hydrogen Venting Schemes[Fuel Cell and Nuclear Enclosures]

Introduction: A hydrogen economy is proposed to mitigate the effects of climate change, using hydrogen fuel cells (housed in enclosures for protection) to generate heat and energy. There is the potential though for hydrogen leaks to develop in the enclosure. Nuclear waste stored in stacked boxes produces hydrogen as a by-product of water decomposition (through corrosion and radiolysis). Hydrogen is a buoyant gas with a flammable range of 4 to 75 % in air. In both cases, leaked hydrogen can build up in confined spaces, with fuel cells the protective enclosure and with nuclear waste boxes in the spaces between the stacked boxes. To prevent flammable mixtures forming, ventilation schemes are used to disperse the hydrogen. Fail-safe passive ventilation schemes are preferred to mechanical systems that are vulnerable to power outages. Thesis: This thesis supports the development of small fuel cell systems by investigating buoyant gas removal from a small enclosure. The thesis hypothesis is that; ‘Safe, passive ventilation parameters can be determined that will manage hydrogen concentrations below the lower flammable limit, for hydrogen leak rates at or below 10 litres per minute in a passively ventilated 0.144m3 hydrogen fuel cell enclosure’. [A 0.144 m3 enclosure houses the BOC Ltd. Hymera small fuel cell environmental unit]. To obtain new data sets the thesis hypothesis, passive ventilation experimental tests using displacement or mixing regimes were undertaken. The tests studied the effects of plain, louvre, chimney and flue ventilation openings applied to the enclosure test rig. Helium was used as a safe analogue for hydrogen in the tests. Findings: The displacement passive ventilation regimes were more effective than the mixing regimes and managed helium concentrations at or below 4 %, but at a leak rate limit of 4 lpm. Louvre vents applied to the enclosure increased flow resistance compared to plain vents increasing enclosure concentrations. Tall chimneys enhanced flow through the enclosure, reducing concentrations compared to shorter chimneys. Horizontal flues can be useful for transporting gas away from the enclosure [through a building wall]. The experimental data was used to validate a series of SolidWorks Flow Simulation CFD models with a good correlation found between the experimental and CFD data sets, supporting its use in enclosure design. The thesis response is that this thesis presents a range of new experimental datasets for passive ventilation in a 0.144 m3 fuel cell enclosure, setting out hydrogen LFL safety limits. In some scenarios, the LFL is breached at a very low leak rate, demonstrating the importance of this safety investigation, as minor leaks can lead to devastating consequences

Nanotechnology Approaches in Chronic Wound Healing

Significance: The incidence of chronic wounds is increasing due to our aging population and the augment of people afflicted with diabetes. With the extended knowledge on the biological mechanisms underlying these diseases, there is a novel influx of medical technologies into the conventional wound care market. Recent Advances: Several nanotechnologies have been developed demonstrating unique characteristics that address specific problems related to wound repair mechanisms. In this review, we focus on the most recently developed nanotechnology-based therapeutic agents and evaluate the efficacy of each treatment in in vivo diabetic models of chronic wound healing. Critical Issues: Despite the development of potential biomaterials and nanotechnology-based applications for wound healing, this scientific knowledge is not translated into an increase of commercially available wound healing products containing nanomaterials. Future Directions: Further studies are critical to provide insights into how scientific evidences from nanotechnology-based therapies can be applied in the clinical setting

Residência para desportistas

A presente investigação, tem como objetivo geral, refletir sobre o contexto e a importância, das Ruas Direitas no território Português. Pretende-se estudar a morfologia urbana da rua direita, através da medição da sua estrutura espacial usando atributos morfológicos para a representação e análise do espaço nomeadamente as Barreiras e Permeabilidades, a Convexidade, a Constitutividade e Axialidade. Identifcado numa fase preliminar um conjunto de ruas direitas em Portugal e respectiva implantação topográfca foram escolhidas três casos de estudo: Rua Direita de Santo Antão (Lisboa) em fundo de vale, Rua Direita da Graça (Lisboa) em cumeada e a Rua Direita de Leiria em encosta. Aferindo que as ruas direitas são um elemento fundamental da cidade portuguesa verifcou-se através da análise dos três casos de estudo que estas apresentam algumas características semelhantes. Assim, os principais resultados da investigação mostraram que existe uma grande uniformidade entre os valores da percentagem de espaço aberto entre as ruas direitas das Portas de Santo Antão e de Leiria. Que no caso da Rua Direita da Graça a percentagem de espaço aberto é muito mais elevada e consequentemente o seu espaço convexo médio também é superior. Que o número de portas por espaço convexo é muito superior na Rua Direita das Portas de Santo Antão fazendo deste o sistema mais constituído de todos - o que se pode traduzir num espaço com maior potencial de movimento e co presença de pessoas que os restantes. Os resultados mostraram ainda que a Rua Direita de Leiria apresenta hoje uma maior centralidade que as restantes, o que se deve possivelmente ao tamanho do sistema urbano (Leiria vs Lisboa) por um lado, mas também ao relevo que isola de alguma forma a colina da Graça e à competição que a Av. da Liberdade apresenta hoje face à Rua Direita das Portas de Santo Antão.The current investigation has as its main goal to reflect about the context and importance of Hight Streets in the Portuguese territory. We wanted to study the urban morphology of Hight Streets by measuring its spacial structure, using morphological attributes for representation and analysis of space, such as: Barriers and Permeability, Convexity, Constitutivity and Axiality. On an earlier stage there was a set of Hight Streets identifed in Portugal and their respective topographic implantation of wich three where chosen: Rua direita de Santo Antão (Lisbon) in a valley bottom, Rua direita da Graça (Lisbon) in a ridge line and Rua direita de Leiria (Leiria) on a hillside. Stating that “Hight Streets” are an essential element in the concept of portuguese city, while analysing the three, earlier mentioned, cases, we found that all of them have similar characteristics. Thus, the main results of this investigation have shown that there is great uniformity percentage of open space values of Portas de Santo Antão and Leiria. The percentage of open space in Rua Direita da Graça is much higher, and consequently, its medium convex space is also larger. The number of doors per convex space much superior in Rua Direita das Portas de Santo Antão, making it the most constituive of all three. Results have also shown that Rua Direita de Leiria, today, shows a larger centrality then the remaining, what is probably due to the size of its urban system (Leiria Vs Lisbon), but also to the relief that somewhat isolates Graça’s hill and also the fact that Avenida da Liberdade has stolen the protagonism of Rua Direita das Portas de Santo Antão

Uso de indicadores para la evaluación de alternativas de valorización de material bioestabilizado mediante la producción de fertilizantes

El presente Trabajo Fin de Máster se enmarca dentro del proyecto VALORCOMP “Valorización de compost y otros desechos procedentes de la fracción orgánica de los residuos municipales” financiado por el Programa de Cooperación INTERREG V-A España-Portugal (POCTEP) y FEDER (Proyecto 0119_VALORCOMP_2_P). El proyecto VALORCOMP está encaminado al desarrollo de tecnologías viables para la recuperación de nutrientes de interés agronómico a partir de los residuos municipales que se tratan en plantas de tratamiento mecánico y biológico. Por lo tanto, se trata de desarrollar nuevos fertilizantes que cumplan la reglamentación vigente. Para ello se ha planteado la recuperación de nutrientes a partir de material bioestabilizado para la obtención de fertilizantes que cumplan la legislación en vigor aplicando para ello métodos de extracción con disolución de KOH y agua. El TFM pretende comparar ambas alternativas desde el punto de vista económico y ambiental, aplicando para ello las métricas de sostenibilidad publicadas por el ICHEME. En el primer caso, solamente es necesario llevar a cabo una etapa de extracción alcalina para obtener un líquido que cumpla con la legislación europea. Sin embargo, cuando se utiliza agua como disolvente, el extracto no alcanza las concentraciones mínimas de nutrientes exigidas para ser considerado fertilizante líquido y para ello es necesario realizar una etapa de concentración posterior mediante evaporación a vacío. Desde el punto de vista ambiental se observa que el proceso de extracción con agua requiere una cantidad de agua muy superior al proceso de extracción con disolución de KOH. Del mismo modo, la energía utilizada por kg de fertilizante producido en el proceso de extracción con agua es mayor. En cuanto al uso de materias primas, cabe destacar que el proceso de extracción con disolución de KOH se requiere el uso de materias primas contaminantes desde el punto de vista de la salud, seguridad y medio ambiente. Desde el punto de vista económico los resultados indican que los costes de equipos, materias primas, inversión y producción anual son superiores en el proceso de extracción con disolución KOH. Sin embargo, el precio de producción de fertilizante es menor. La cantidad de fertilizante producida en el proceso de extracción con disolución de KOH es de 421,95 kg/h; mientras que en el caso de extracción con agua es de 39,38 kg/hDepartamento de Ingeniería Química y Tecnología del Medio AmbienteMáster en Ingeniería Ambienta

Design of tilting rotary table

Cílem této diplomové práce je konstrukční návrh naklápěcího otočného stolu s řízenou čtvrtou a pátou osou pro CNC centrum.První část práce obsahuje rešerši v oblasti otočně naklápěcích stolů .Druhá část práce obsahuje volbu technických parametrů otočně naklápěcího stolu pro vybrané CNC centrum,návrh možných variant řešení,výběr vhodné varianty ,konstrukční návrh vybrané varianty.The aim of this thesis is the design of the rotary tilting table controlled the fourth and fifth axis for CNC centrum.První part includes the search for pivotally tilting tables. The second part includes the choice of technical paremetrů pivotally tilting table for selected CNC center, design of possible options , selection of appropriate options, design of the selected option.

On the Modelling of the Freight Traffic in Helsinki Region

Työn alussa esitellään Helsingin seudun tavaraliikennejärjestelmän olennaiset piirteet, käsitellään tavaraliikenteen mittaamisen nykytilaa ja tarpeita. Loppupuolella mallinnetaan tavaraliikenteen matkatuotokset pääkaupunkiseudulla, tavaraliikenteen terminaalien sijoittuminen ja tavaraliikenteen matkojen suuntautumiset Tuupakan logistiikka-alueelta. Terminaalien sijoittumismallinnusta pohjustaa luku, jossa esitellään maankäytön mallintamisen perusperiaatteet. Lopuksi vielä käsitellään Liikenne- ja viestintäministeriön käyttämän Frisbee-tavaraliikennemallin soveltuvuutta Helsingin seudulle pitkämatkaisen tavaraliikenteen mallintamiseen. Helsingin seudulla on keskeinen rooli koko maan tavaraliikennejärjestelmässä, sillä seudulla sijaitsee Suomen suurimpiin kuuluva Vuosaaren satama, ja Helsingin seudulla sijaitsevat tukkuliikkeiden isot valtakunnalliset varastot. Helsingin seutu on myös koko maan suurin yksittäinen kulutuskeskus. Tuotantokeskuksena Helsingin seutu ei ole yhtä tärkeä. Tavaraliikennejärjestelmä nojaa pitkälti maantiekuljetuksiin ja Kehä III:n varrella sijaitsevaan Suomen isoimpaan logistiikkakeskittymään. Tavaraliikenteen mittaamisessa on paljon uuden tekniikan avaamia kehitysmahdollisuuksia. Myös tarvetta tavaraliikennettä tarkemmin varsinkin kaupungeissa selvittäville liikennetutukimuksille on, jos tavaraliikennettä halutaan mallintaa samalla tarkkuudella kuin henkilöliikennettä. Maankäytön mallintamisen periaatteet eivät ole kovin hankalia ja eivätkä eroa suuresti liikenteen mallintamisen periaatteista. Käytännössä mallintaminen ei kuitenkaan usein edes onnistu, sillä maankäytön lajeja niille ominaisine dynamiikkoineen on yksinkertaisesti liikaa. Kuitenkin rajaamalla tutkimusasetelmia sopivasti maankäytön mallinnuksella saadaan käyttökelpoisia tuloksia esimerkiksi, kun halutaan arvioida liikenneverkon muutosten vaikutuksia kaupunkirakenteeseen. Tavaraliikenteen matkatuotokset arvioitiin yhdistämällä paikkatietoja pääkaupunkiseudun eri toimialojen yritysten sijainneista Ympäristöministeriön suunnitteluohjeista saatuihin matkatuotoksiin maankäytön eri lajeille. Saatu tulos on uskottava. Terminaalien sijoittumista mallinnettaessa selvisi, että pelkästään keskeisimpiä tekijöitä käyttäen ei saada selitettyä terminaalien nykysijainteja. Käytetty menetelmä Tuupakan alueen tavaraliikenteen matkojen suuntautumisen mallintamiseksi osoittautui lupaavaksi, joskaan pienen havaintoaineston takia ei voida tehdä kovin pitkälle meneviä päätelmiä

Quality control of construction of apartment building

Import 26/06/2013Cílem této bakalářské práce je zpracovat kontrolní a zkušební plány hrubé stavby dle zadaného objektu. Bytový dům se skládá z jednoho podzemního podlaží a třech nadzemních podlaží. Bakalářská práce je rozdělena do pěti částí, úvodní, technologická, podklady, přílohy a stavební. V části úvodní je zadání bakalářské práce včetně ostatních náležitostí. Technologická část obsahuje stručný popis stavebních činností hrubé stavby a po té se zaměřuje na postupný popis jednotlivých kontrol stavebních prací a případných jejich zkoušek. Část podklady zahrnuje technické listy jednotlivých použitých materiálů. Část přílohy zahrnuje vypracované kontrolní a zkušební plány. Poslední část mé práce tvoří výkresová dokumentace.The objective of this thesis is elaboration of control and test plans shell construction according to the specified object. Apartment building consists of one basement and three floors. Bachelor work is divided into five parts, introductory part, technology part, materials, appendices and construction part .The introductory part consists of placing of the bachelor’s thesis and other elements. Technological part contains brief description of the performing of individual technological stages of the shell structure of the construction and after that focuses on the description of each successive controls of the construction work and its possible testing. Material part includes technical data sheets of the materials. Appendices part includes elaboration of control and test plans. The last part of my thesis consists of drawings.Prezenční225 - Katedra pozemního stavitelstvívelmi dobř