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Karbonatisering av modernt kalkputs med hydraulisk inblandning / Carbonation of modern lime mortar whith hydraulic mixHossainy, Shokoufeh January 2022 (has links)
Kalkbruk har använts i tusentals år som byggnadsmaterial i byggkonstruktioner.Senare, under 1800-talet, började en variant av hydraulisk kalk, kallad vattenkalk, att användas. Det hydrauliska kalkbruk som används idag i byggnadskonstruktioner såsom fasadmurning, putsning, fogning av murverk har blivit mer vanligt att använda i stället för cementbruk, eftersom det finns fler fördelar med kalkbruk som har hydraulisk inblandning än med det cementbaserade bruket. Kalkbruk används särskilt till renovering av äldre byggnader där kalk eller hydrauliska kalkbruk sedan tidigare har använts. Det hydrauliska kalkbruket utvinns från kalksten men den hydrauliska kalk som bränns av oren kalksten kallas naturligt hydraulisk kalk och tillverkas av Saint-Astier i Frankrike. Kalken har inga hydrauliska tillsatsmedel som cement, gips, flygaska eller puzzolana material. Enligt SS-EN 459–1:2015 klassas den naturliga hydrauliska kalken efter hållfasthet, och tillverkas i tre klasser: NHL 2, NHL 3,5 och NHL 5.Naturliga hydraulisk kalkbruken har för- och nackdelar, Produktens fördelar avses av de som använder bruket överväga nackdelarna. NHL-bruk passar bättre i fuktiga miljöer, det kan återanvändas, är miljövänligt, rent och naturligt, tål mer påfrestningar och driftstiden är mindre. Bakgrunden till arbetet är att NHL-bruks användning har blivit allt vanligare under de senaste decennier vid renovering av äldre kalkputsade byggnader. Väderförhållande och temperatur är av stor betydelse för att ha ett hållbart resultat inom kalkputsarbetet och således kan orsaka en viss försening i tidplaner och byggtider. Emedan nya metoder ska utreda och utvärderas för att få det optimala resultatet.Litteraturstudier, laboratorietester och intervjuer har använts för att kunna nå examensarbetets mål. Flera små tester har gjorts för att undersöka karbonatiseringsprocessen under olika väderförhållandet. Testerna visar att det naturliga kalkbruket karbonatiserar bättre och snabbare i en fuktig miljön, vilket passar det klimat som råder i Norden och i kustklimat. Det naturliga hydrauliska kalkbruket är dock ett material som kräver mer erfarenhet för att kunna uppnå bästa resultat för detta ändamål. Att vädret har stort betydelse för karbonatiseringsprocessen är ett resultat som framkommit i tidigare studier och forskning, vilket också de tester som utförts under detta arbete visar. Arbete med hydrauliska kalkbruk bör därför ske under perioder som passar kalkputsarbetet för att det ska hinna karbonatisera innan det riskerar att utsättas för påfrestning. En lämplig period är därför maj till oktober som den bästa perioder för kalkputsarbete.Naturliga hydrauliska kalkbruk utvecklas kontinuerligt, vilket kan bidra till att de kan ersätta det cementbaserade kalkbruket i framtiden utan några negativa konsekvenser såsom frostsprängning och låg hållfasthet. / The aim of the work was to analyze the carbonation of modern lime plaster with hydraulic mixing. Requirements for a certain carbonation can cause delays in schedules and construction time. The hydraulic lime mill is obtained from limestone, while the hydraulic lime burned by crude limestone is called natural hydraulic lime, which is manufactured by Saint-Astier in France. the lime has no hydraulic additives such as cement, plaster, fly ash or puzzolana materials. Natural Hydraulic lime mills fit better in the humid environment, it can be reused, is environmentally friendly, is clean and natural, can withstand more stress and the operating time is less. During the work, a study visit was made to an ongoing work process at Elin Wägnerskolan in Växjö, which Karlssons fasad AB had taken over the restoration responsibility. Interviews were conducted with one of the players at Målarkalk AB, which is one of the largest suppliers in the lime industry and project manager at Karlssons Fasad AB. Several small tests have been done to see the carbonation process under different weather conditions. The tests show that natural lime farming carbonates better and faster in a humid environment, which suits the Nordic countries and coastal environments. Natural hydraulic lime mills are well suited to replace cement-based mortars in the future without any negative impact.
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Water dynamics in the rhizosphere / How mucilage affects water flow in soilsKröner, Eva 10 February 2016 (has links)
Die Wurzelwasseraufnahme aus dem Boden wird durch die Rhizosphäre beeinflusst. Die Rhizosphäre ist eine dünne Bodenschicht, die sich um Wurzeln herum bildet. Die Rhizosphäre wird durch Mucilage beeinflusst. Mucilage ist ein polymeres Gel, was von Wurzeln abgesondert wird und vor allem die hydraulischen Eigenschaften der Rhizosphäre verändert. Wenn es im Kontakt mit Wasser ist, kann Mucilage große Mengen an Wasser aufnehmen, aber wenn es trocken ist, wird seine Oberfläche hydrophob.
Hier konzentrieren wir uns auf den Effekt von Mucilage auf die hydraulischen Eigenschaften des Bodens. Zunächst präsentieren wir experimentelle und numerische Studien, die die hydraulischen Prozesse in der Rhizosphäre nach der Bewässerung von trockenem Boden beschreiben. Bei Mucilagekonzentrationen, die niedriger als ein gewisser Schwellwert waren, konnte Wasser durch die Rhizosphärenschicht fließen, über dieser Konzentration wurde die Schicht wasserundurchlässig während der ersten Minuten bis zu Stunden nach Bewässerung. Wir präsentieren eine analytische Abschätzung der Mucilagekonzentration an der Perkolationsschwelle als Funktion von mittlerer Teilchengröße und Bodenwasserpotential nach Bewässerung. Die Abschätzung wurde an Hand von Experimenten des kapillaren Aufstiegs in Bodensäulen validiert.
Wir entwickelten ein effektives Model um zu beschreiben, wir Mucilage die hydraulischen Funktionen des Bodens verändert: (a) Quell- und Trocknungsprozesse von Mucilage resultieren in Nicht-Gleichgewichtsdynamiken zwischen Wassergehalt und Wasserpotential, (b) die Präsenz von Mucilage im Boden reduziert das Wasserpotential bei einem gegebenen Wassergehalt und (c) Mucilage ist viskos und reduziert dadurch die hydraulische Leitfähigkeit des Bodens bei einem gegebenen Wassergehalt.
In Experimenten mit Boden-Mucilage-Mischungen testeten wir das Model und wandten es an, um Beobachtungen von früheren Experimenten mit echten Pflanzen zu simulieren, die veränderte hydraulische Dynamiken in der Rhizophäre zeigen.
Im Anhang dieser Arbeit sind zwei Studien zur Wärmeausbreitung von Erdkabeln. Hier können hydraulische Dynamiken autreten, die dem radialen Wasserfluss zu einer einzelnen Wurzel ähneln.
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Hydraulic fluids with new, modern base oils – structure and composition, difference to conventional hydraulic fluids; experience in the fieldBock, Wolfgang, Braun, Jürgen, Schürrmann, Tobias 28 April 2016 (has links) (PDF)
The paper describes the comparison and the difference of modern hydraulic fluids compared to conventional hydraulic fluids. A comparison of different base oil groups, solvent neutrals, group I and comparison with hydrotreated/hydroprocessed group II and/or group III base oils is presented. The influence on oxidation stability, elastomer compatibility, carbon distribution and physical properties is outlined.
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Active Fluid Borne Noise Reduction for Aviation Hydraulic PumpsWaitschat, Arne, Thielecke, Frank, Behr, Robert M., Heise, Ulrich 27 April 2016 (has links) (PDF)
The aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides strong limits on component weight and size, high safety and reliability standards demand simple solutions. Hence, basic silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the-art aboard commercial aircrafts. Unfortunately, they do not meet today’s noise attenuation aims regarding passenger comfort and equipment durability. Significant attenuation performance is expected from active concepts that generate anti-phase noise. However, such concepts remain a long term approach unless related costs, e.g. due to additional power allocation and real-time control equipment can be avoided. In this paper an active fluid borne noise attenuation concept is discussed that accounts for the mentioned constraints. An aircraft hydraulic pump is considered as main noise source. The active attenuator is an in-house rotary valve design. The basic feature is a known direct shaft coupling principle of pump and rotary valve, so no speed/ frequency control of the valve and no separate power supply are required. The common-shaft principle is further simplified here and proposed as integral feature of future “smart pumps”.
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Simulation and design of energized hydraulic fracturesFriehauf, Kyle Eugene 23 October 2009 (has links)
Hydraulic fracturing is essential for producing gas and oil at an economic rate from low permeability sands. Most fracturing treatments use water and polymers with a gelling agent as a fracturing fluid. The water is held in the small pore spaces by capillary pressure and is not recovered when drawdown pressures are low. The un-recovered water leaves a water saturated zone around the fracture face that stops the flow of gas into the fracture. This is a particularly acute problem in low permeability formations where capillary pressures are high. Depletion (lower reservoir pressures) causes a limitation on the drawdown pressure that can be applied. A hydraulic fracturing process can be energized by the addition of a compressible, sometimes soluble, gas phase into the treatment fluid. When the well is produced, the energized fluid expands and gas comes out of solution. Energizing the fluid creates high gas saturation in the invaded zone, thereby facilitating gas flowback. A new compositional hydraulic fracturing model has been created (EFRAC). This is the first model to include changes in composition, temperature, and phase behavior of the fluid inside the fracture. An equation of state is used to evaluate the phase behavior of the fluid. These compositional effects are coupled with the fluid rheology, proppant transport, and mechanics of fracture growth to create a general model for fracture creation when energized fluids are used. In addition to the fracture propagation model, we have also introduced another new model for hydraulically fractured well productivity. This is the first and only model that takes into account both finite fracture conductivity and damage in the invaded zone in a simple analytical way. EFRAC was successfully used to simulate several fracture treatments in a gas field in South Texas. Based on production estimates, energized fluids may be required when drawdown pressures are smaller than the capillary forces in the formation. For this field, the minimum CO2 gas quality (volume % of gas) recommended is 30% for moderate differences between fracture and reservoir pressures (2900 psi reservoir, 5300 psi fracture). The minimum quality is reduced to 20% when the difference between pressures is larger, resulting in additional gas expansion in the invaded zone. Inlet fluid temperature, flowrate, and base viscosity did not have a large impact on fracture production. Finally, every stage of the fracturing treatment should be energized with a gas component to ensure high gas saturation in the invaded zone. A second, more general, sensitivity study was conducted. Simulations show that CO2 outperforms N2 as a fluid component because it has higher solubility in water at fracturing temperatures and pressures. In fact, all gas components with higher solubility in water will increase the fluid’s ability to reduce damage in the invaded zone. Adding methanol to the fracturing solution can increase the solubility of CO2. N2 should only be used if the gas leaks-off either during the creation of the fracture or during closure, resulting in gas going into the invaded zone. Experimental data is needed to determine if the gas phase leaks-off during the creation of the fracture. Simulations show that the bubbles in a fluid traveling across the face of a porous medium are not likely to attach to the surface of the rock, the filter cake, or penetrate far into the porous medium. In summary, this research has created the first compositional fracturing simulator, a useful tool to aid in energized fracture design. We have made several important and original conclusions about the best practices when using energized fluids in tight gas sands. The models and tools presented here may be used in the future to predict behavior of any multi-phase or multi-component fracturing fluid system. / text
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Stem hydraulic architecture and xylem vulnerability to cavitation for miombo woodlands canopy tree speciesVinya, Royd January 2010 (has links)
Africa's miombo woodlands constitute one of the most important dry tropical forests on earth, yet the hydraulic function of these woodlands remains poorly researched. Given the current predictions of increased aridity by the end of this century in the miombo ecoregion, understanding the likely response of miombo woodlands tree species to water stress is crucial in planning adaptation strategies. Predicting the response of miombo woodlands to future climate trends is hampered by a lack of knowledge on the physiology of the common miombo woodlands tree species. In particular, plant-water relations for this woodlands type are not well understood. An understanding of plant-water relations for this woodlands type will provide insights into how water limits tree species distribution in this ecosystem. This will also improve our prediction model on the likely response of this ecosystem to predicted climate change. For this reason, the overall objective of this research was to evaluate the hydraulic architecture and xylem vulnerability to cavitation for nine principal miombo woodlands tree species differing in drought tolerance ability and habitat preference. This was achieved by; examining the hydraulic properties and evaluating the extent to which each hydraulic design was vulnerable to water stress-induced xylem cavitation; investigating how seasonal changes in plant-water relations influences seasonal patterns of leaf display and; analyzing the relationship between stem hydraulic supply and leaf functional traits related to drought tolerance ability. This research has found that drought-intolerant tree species with mesic specialization have more efficient stem hydraulic systems than co-occurring habitat broad ranging species. Broad ranging tree species attain wider habitat distribution by adjusting their hydraulic supply in response to changing ecosystem water availability. The finding that hydraulic properties differ significantly between tree species with contrasting habitat preference suggests that tree hydraulic design may have some adaptive ecological role in influencing species habitat preferences in miombo woodlands. The evaluation of xylem vulnerability to cavitation revealed that mesic specialized tree species were more vulnerable to water stress-induced cavitation than habitat broad ranging tree species. Vulnerability to cavitation in individuals from the same broad-ranging species growing in contrasting habitats showed only marginal and statistically insignificant (P > 0.05) differences between wet and dry sites. In the investigation of the influence of seasonal changes in stem water relations on seasonal leaf display, seasonal rhythms in stem water status were found to exert significant controls on leaf phenology. Mesic specialists had strong stem water controls throughout the year in comparison to broad ranging tree species. An analysis of the relationship between stem hydraulic supply and leaf functional traits suggests that stem hydraulic supply constrains leaf biomass allocation patterns among miombo tree species. Mesic specialists tend to invest more in leaf longevity than broad ranging tree species. This thesis has uncovered some interesting relationships between plant-water-relations and the distribution of miombo woodlands tree species. These results lead to the conclusion that in an event of increased ecosystem drying under future climate trends, tree species with mesic specialisation are at a greater risk of experiencing cavitation related species mortality than broad ranging ones.
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Optimalizace hydraulického systému a jeho prvků pro malá dopravní letadla / Optimization of Hydraulic System and its Components for Commuter Category AirplanesKameník, Luboš January 2012 (has links)
The dissertation thesis deals with optimization of the selected areas of the hydraulic system for small and medium transport aircrafts. Newly developed small aircraft EV-55 is a representative in the category of the small aircrafts . The selected areas of the hydraulic systems , important and useful for domestic producers of the hydraulic devices and whole hydraulic systems for the airplane EV-55 , are subjected to optimization efforts in the dissertation thesis. Design parameters of the hydraulic system (type of hydraulic source, level of pressure, weight of connecting tube), hydraulic devices ( tribology, machining process), simulation of the servomechanism and areas of diagnostic of technical status of the hydraulic system are optimized in the dissertation thesis.
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Controlador de posição linear hidro-pneumático. / Hydro pneumatic linear position controller.Jesus, Sidney Nogueira Pereira de 27 March 2008 (has links)
Nessa pesquisa é apresentada uma inovação tecnológica em aplicações de controle de posição em máquinas e/ou dispositivos: o Controlador de Posição Linear Hidro- Pneumático. Para os casos nos quais têm-se grandes esforços combinados com pequenos deslocamentos, normalmente esse trabalho é feito com o uso de Sistemas Servo-Hidráulcos nos quais, devido às características mencionadas do nicho de mercado visado pela presente proposta, representam um custo elevado quando comparado com a solução Hidro-Pneumática aqui descrita. Salienta-se a simplicidade da infra-estrutura requerida para a instalação dessa alternativa, e também a redução do desperdício energético com relação à tecnologia tradicional com a Servo-Hidráulica. Observou-se nos testes com o protótipo, um excelente desempenho do sistema em termos de rapidez de resposta, como ainda no quesito resolução de posicionamento cujos valores encontrados apresentam-se na casa de 0,05 segundos e 0,01 mm, respectivamente. O pequeno tamanho físico obtido com essa nova tecnologia é outro item relevante, permitindo-se o seu emprego em locais de reduzido espaço disponível. . Resultados de simulações numéricas e de testes experimentais são apresentadas, bem como perspectivas de desenvolvimentos futuros. / This research presents a technological innovation for applications in machine / device position control: the Hydro-Pneumatic Linear Position controller. In cases where great efforts are combined with small dislocations, this task is normally accomplished by means of Servo Hydraulic Systems that, due to particular characteristics of the market envisaged by the present proposition, represent elevated costs, when compared to those of the hydro-pneumatic solution described here. This work presents an analytical numerical model for the devise as well as an experimental prototype. It worth noting the infra-structure simplicity required for this alternative implementation, and also the reduction in energy waste when compared to the traditional servo-hydraulic technology. The prototype experimental tests demonstrated the system excellent behavior in what concerns answer speed and position resolution whose values were respectively in range 0.05 s and 0,01 mm. The small physical size obtained with this technology is another relevant item, which allows the device use in places of reduced available space. Numerical simulation and experimental test results are presented as well as perspectives of future developments
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Condutividade hidráulica de materiais de baixa permeabilidade: desenvolvimento, construção e teste de um sistema de medida / Hydraulic conductivity of low permeability materials: development, construction and test of a measurement systemDourado, Kleber Azevedo 19 September 2003 (has links)
Este trabalho trata do desenvolvimento, montagem e teste de equipamentos para ensaios de materiais de baixa condutividade hidráulica, o qual inclui sistemas de controle hidráulico de volume constante, permeâmetros do tipo parede flexível e interfaces água-percolante. A vantagem desse arranjo está no maior controle dos ensaios e, notadamente, na redução do tempo de ensaio com emprego do sistema hidráulico de volume constante (sistema fechado), quando comparado aos ensaios que empregam o sistema aberto de controle hidráulico. Para testar o equipamento, foram ensaiados geocompostos bentoníticos (geosynthetic clay liners - GCLs) de fabricação nacional, em corpos de prova moldados com diâmetro de 100 mm e também, em uma mistura de solo com bentonita. Os resultados da condutividade hidráulica obtidos para os geocompostos bentoníticos se situaram na ordem de \'10 POT.-9\' e \'10 POT.-10\' cm/s, compatíveis com os publicados na literatura sobre o material, e os ensaios na mistura solo-bentonita produziu resultados na ordem de \'10 POT.-8\' cm/s, e foram conseguidos com cerca de 3 horas de ensaio. Aborda-se ainda a aplicabilidade da lei de Darcy aos materiais ensaiados. / This work describes the development, construction, calibration and test of equipment for testing low hydraulic conductivity materials, which includes constant volume hydraulic control system, flexible wall permeameters and permeating water interfaces. The advantage of this kind of apparatus is the greater test control, notably, the reduction of test duration due to the use of a constant volume hydraulic system (closed system), when compared to the opened system hydraulic control test. In order to test the equipment, geosynthetic clay liners (GCLs) manufactured in Brazil was used as test specimens of 100 mm diameter and also, a mixture of soil and bentonite. The results of hydraulic conductivity obtained for the GCL were in the range of \'10 POT.-9\' to \'10 POT.-10\' cm/s, comparable to what has been published by the specialized literature on this material, and the tests with the soil-bentonite mixture resulted in a conductivity about \'10 POT.-8\' cm/s, after 3 hours running the test. The applicability of Darcy´s law to the tested materials is also referred to.
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A Study on Sustainable Development Strategy of Jack Lifting Method ¡V A Case of R CompanyLee, Tsung-Hsin 15 August 2011 (has links)
Lifting method through the use of hydraulic jacks, can adjust column elevation of the structure in order to eliminate the stress burden caused by differential settlement , as well as recover the structure¡¦s initial state and force to avoid the form reconstructing caused by different over-settlement, save construction cost and reduce environmental impact, and so the life cycle of the building be able to last. The study based on ¡§The computer control system of hydraulic jacks¡¨, ¡§The repair method of settlement of floating roof tank¡¨, and the other technologies, which developed by lifting method development department, set up by the case company, has matured day by day to seek permanent development strategy through the utilization of the innovative lifting method in structure on reclaimed land or tanks, shop buildings, and structures which have different settlement problems, and so on, enable to last the life cycle of the building.
This study consists of the information collection of lifting technology development through the literature of innovative technology and management strategy and interview of the owner and the decision-making manager of the case company, that total sum of person-time is 21, with the theme of the technical development of lifting method, the extension of market, and the internationalization. Making industry S.W.O.T analysis can not only find out the lifting development business of the case company but also the strategic direction, core competitiveness, the development direction, the permanent strategy to maintain the annual growth of the rate of marginal balance.
According to research, the case company need to become a international company in order to maintain the annual growth of 20¢H of the operational goal. Taking Taiwan as the technical development center, the case company uses the local manpower and constructional material of the group¡¦s subsidiaries in overseas footholds to lower the quote cost and enhance the competitiveness, so that the case company can move toward internationalization gradually. Besides, to be competitive in lifting industry, the case company must be customer oriented, which means to design the unique custom-made lifting method for the customer¡¦s demand. Contenting customer¡¦s demand with cost, industry safety and time is the most important strategy to retain long-term competitiveness advantage. In strategic growth oriented, to be the top lifting company all over the world after one decade, the case company has to enhance core competitiveness of lifting method, including project management, project control, structural design capacity, computer control hydraulic jacks system development capabilities, and technical capabilities lifting. Meanwhile, the case company has to develop continuously new technologies and methods, combine with the group¡¦s subsidiaries to establish overseas footholds to extend the overseas market, train staff to obtain the international certificate and learn the second language, and makes the product and service different from other companies.
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