199,020 research outputs found
How to integrate energy-saving architectural instruments towards a holistic energy neutral ice rink design: Manual towards an energy neutral ice rink
No full textAn ice rink building can be described as an active machine. It needs electric energy to fulfill its purpose: to provide artificial ice to - initially - extend the ice skating season.Nowadays the need of artificial ice has increased, since the oppurtunity to practice the ice skating sport outside with natural circumstances ceased to exist. The main cause of this development is the increasing annual temperature, which has been a result of global warming.Due to this climate change, an ice rink building will soon be the only means to practice the sport.Another development is the increasing demands of the ice skaters to have the right circumstances to enhance their sporting performance.The architectural typology of the ice rink had been initiated in the 1980’s, before that speed skating on artificial ice had mainly been practiced outdoors. This newly introduced architecture merely played a role as a shell of protection, but is low performing in controlling the right circumstances for high-quality ice and comfort of the sporter.The ice rink building nowadays is still generally challenged in providing a controllable environment and the typology is still associated with being occupied in winter, and vacated in summer. The ice rink typology can be described as unsustainable.The directive of the research is to find architectural means to improve an ice rink in its sustainable characteristics. This is mainly focussed on lowering the energy demand by application of architectural solutions, and compensating this energy demand by integrating energy producing elements.For this research, mainly the usage/operation stage will be taken into account. For the construction stage (choice of materials and their embodied energy) only assumptions will be made to improve the buildings energy sustainability. The result will be an energy neutral ice rink.To gain insight in the building requirements, case studies of ice rink predecessors and questionnaires on larger potential user groups were necessary. To go into depth of the building characteristics and usefull feedback on how to design an ice rink, specialists in the ice rink field were interviewed. Where needed the research was expanded with literature studies.Outcomes of the research are, among others, a roof and a double facade acting as an climatic buffer, insulation in the building envelope, avoidance of heat radiation by the sun or surrounding materials, strong climate regulation devices, and a hermetically sealed sport area as protection from its outer environment. In the end the building design will provide an ice sport venue in winter and multifunctional venue in summer with its own fully controllable micro climate.These solutions will be applied in a program of requirements for a design proposal of the ice rink of the future.Architecture, Urbanism and Building Sciences | Explorela
Effect of softening on “bound” rubber and strain induced crystallization in filled rubber compound
No full textA dive into rubber: structure-property correlation
No full textAn extended characterization of several compounds, differing in the nature of the rubbery matrix (Natural rubber, Butadiene Rubber, Isoprene Rubber) as well in the type and content of the filler adopted (carbon black, silica), have been characterized under different loading conditions (uniaxial, biaxial and pure shear loading conditions) from the small strains (DMA) up to fracture. A correlation between the structural features of the compound and its mechanical behaviour has been proposed for the different materials under consideration
MOBILE ICE RINK CONSTRUCTION IN VELENJE
No full textV diplomskem delu je na kratko opisana zgodovina hladilnih sistemov ter drsališč. Nato so opisani hladilni sistemi, njihove komponente, kako skupaj delujejo in čemu so namenjeni. V nadaljevanju je na primeru mobilnega drsališča v Velenju predstavljeno postavljanje in delovanje mobilnega drsališča ter opisano njegovo vzdrževanje. V zadnjem delu so predstavljeni stroški, ki jih takšen projekt ima in njihova odvisnost od temperatur okolice.This thesis presents a short history of cooling systems, ice rinks aswell as an overview of cooling systems and their components. There is also an explanation to how these systems work and what they are used for. In the example of a mobile ice rink in Velenje there is an explanation of how a mobile ice rink is constructed, how it works and how it is maintained. In the last part of the thesis there is a presentation of overall costs of such a project and how the temperature of the air affects the costs of the cooling system
SUBSTANTIATION OF THE PARAMETERS OF TILLAGE RINK
No full textThe purpose of research is improving the quality of surface tillage during sowing of winter crops and, as a result, crops yield increasing. Quality compacting soil tillage rinks affect its physical and mechanical properties, such as moisture content, structure, and density, optimum value of which is regulated agronomic requirements for cultivation of specific agricultural crops. These properties affect the quality of seeding and water-air regime of the soil. Therefore, when conducting experimental studies, moisture content, structure, and soil density was controlled to optimize parameters and modes of operation of the rink to bring the above soil properties in compliance with agro-technical requirements. The quality of soil the proposed rink was assessed in comparison with existing rinks. The criterion of quality was the factor of conformity to the standard kcs, which characterizes the compliance of the density and structure of the soil reference values established by the agrotechnical requirements. The result of the research revealed that the maximum value of kcs = 0.84 is achieved at a speed ofv = 11 km/h and the ballast mass m = 78 kg. After tillage rinks seeder the factor of conformity to the standard kcs = 0.68; after soil tillage the existing rink kcs = 0.71; and after the processing of the proposed soil-cultivating rink the factor of conformity to the standard amounted to kcs = 0.84, which is significantly higher than after soil tillage of existing rink. While the specific metal content of the proposed ice rink will not exceed 116 kg per 1 m of width, which is 2.4 times less than that of the rink 3CCH-6 (283.6 kg/m).</jats:p
Selbstreguliertes Lernen im Inverted Classroom. Lernmotivation in ingenieurwissenschaftlichen Studiengängen
No full textRink M. Selbstreguliertes Lernen im Inverted Classroom. Lernmotivation in ingenieurwissenschaftlichen Studiengängen. Sozialwissenschaften heute . Vol 7. Bielefeld: wbv Media; 2021
Die Hochschule steht Kopf?! Implementations- und Durchführungshindernisse beim Inverted-Classroom-Modell
No full textRink M, Neuhaus T. Die Hochschule steht Kopf?! Implementations- und Durchführungshindernisse beim Inverted-Classroom-Modell. Die Hochschule – Journal für Wissenschaft und Bildung. 2022;2022(2):68-81
Korteweg–de Vries and Fermi–Pasta–Ulam–Tsingou: asymptotic integrability of quasi unidirectional waves
No full textIn this paper we construct a higher order expansion of the manifold of quasi unidirectional waves in the Fermi–Pasta–Ulam–Tsingou (FPUT) chain. We also approximate the dynamics on this manifold. As perturbation parameter we use h^2 = 1/n^2, where n is the number of particles of the chain. It is well known that the dynamics of quasi unidirectional waves is described to first order by the Korteweg–de Vries (KdV) equation. Here we show that the dynamics to second order is governed by a combination of the first two nontrivial equations in the KdV hierarchy—for any choice of parameters in the FPUT potential. On the other hand, we find that only if the parameters of the FPUT potential satisfy a condition, then a combination of the first three nontrivial equations in the KdV hierarchy determines the dynamics of quasi unidirectional waves to third order. The required condition is satisfied by the Toda chain. Our results suggest why the close-to-integrable behavior of the FPUT chain (the FPUT paradox) persists on a time scale longer than explained by the KdV approximation, and also how a breakdown of integrability (detachment from the KdV hierarchy) may be responsible for the eventual thermalization of the system
Environmental stress cracking of high-density polyethylene under plane stress conditions
No full textHigh-Density Polyethylene is prone to Environmental Stress Cracking if mechanically stressed in the presence of solutions containing surfactants. Even if this polymer is widely used to produce containers for industrial and household detergents, its Environmental Stress Cracking Resistance is generally evaluated under plane strain conditions irrespective of the actual stress state experienced during service life. In this work the Slow Crack Growth of thin specimens, under plane stress conditions, was studied in air and in the presence of an “active” environment. The J-integral approach was adopted to account for the extensive plastic deformations thereby occurring and the obtained results were compared to those describing the plane strain behaviour of the same polyethylene, reported in previous works. The effect of the production process was also assessed by comparing the behaviour of compression moulded and blow moulded specimens, the latter having a lower degree of crystallinity. Despite the difference in fracture resistance expected in air, the behaviour in presence of the active environment was very similar, suggesting that the production process has only negligible influence on the Environmental Stress Cracking resistance of the considered polyethylene
Fracture behaviour of carbon black filled natural rubber: effect of temperature, strain rate and strain induced softening
No full textThe fracture toughness of filled rubber compounds is strongly dependent on the capability both of the filler/rubber network to orient and of the rubber matrix to crystallize under straining and on the possibility that not catastrophic dissipative deformation mechanisms take place when the rubber compound is largely deformed. All these phenomena may become time dependent due to the presence of low mobility rubber originating from the interactions between polymer chains and filler particles. The dependence of the fracture behavior of carbon black filled natural rubber compounds on temperature and displacement rate was evaluated. The role of the complex structure of such compounds has been evidenced by comparing the facture behavior of pristine and previously strained compounds
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