Investigations for Ergonomic Presentation of AIS Symbols for ECDIS

Empirical investigations were carried out in a research project for the German Federal Ministry of Transport, Building, and Housing to evaluate the presentation of AIS target information on ECDIS. The investigations were performed at three international simulation centres. The features, colour and fillingjsize of AIS symbols, as well as the influence of the ECDIS display category on the detection of AIS targets were the main issues of the investigations. Results show that blue (5-52 colour token RE5BL) is the most suitable colour of the tested colours for the presentation of AIS targets under all ambient light conditions on the tested IHO S-52 colour tables

Size effects in fracture mechanics: A detailed investigation on crack growth at the micro- and mesoscale

Fracture mechanics are strictly regulated by standards. This includes limitations of specimen size as a function of plastic zone size. Since the size of the plastic zone mainly depends on the material itself, the established macroscopic test procedures cannot be easily downscaled when sample size decreases to the microscale. With advances in micromechanical testing, the classical size effect in metals, whereby the strength increases as specimen dimensions become smaller, has been studied in detail. Please click Download on the upper right corner to see the full abstract

Acquiring in situ Fatigue Crack Growth Curves by a Compliance Method for Micro Bending Beams to Reveal the Interaction of Fatigue Cracks with Grain Boundaries

To understand the interaction of dislocations with microstructural obstacles it is necessary to find test methods which are able to resolve the interaction of only a single or few defects with obstacles like interfaces. Therefore, the investigation of micro specimens has been established over the years as a suitable method to test the influence of microstructural features on the mechanical response. While quasi-static loading of micro specimens has been carried out extensively in the past decade and has given powerful insights on the mechanical behavior at small scales, cyclic loading and fatigue crack growth experiments still provide a challenge. In order to check the possibility to systematically initiate and monitor fatigue crack growth rates in micro specimens, we cyclically loaded micro bending beams made of a nickelbase superalloy. Furthermore, for grain boundaries of differing types we checked if the crack growth curves are suitable to measure crack - microstructure interactions. The fatigue cracks showed a deceleration when approaching the grain boundaries followed by an abrupt re-acceleration, which is in accordance to macroscopic experiments and connected to dislocation or slip transfer from the plastic zone of the crack through the grain boundary. Furthermore, we observed a dependency of the deceleration on the grain boundary type and the crystallographic orientation of the neighboring grains. A 3D-HR-orientation gradient map was gathered by HR-EBSD using the software CrossCourt in combination with a self-provided MATLAB tool to reveal detailed information about strain localization at the grain boundary in the process zone near the crack tip

Fatigue crack growth in micro specimens as a tool to measure crack–microstructure interactions

The process of short fatigue crack growth plays a significant role for the lifetime of materials in the high and very high cycle regimes. Fatigue crack growth is strongly influenced by interactions with microstructural obstacles, such as grain boundaries or phase boundaries, requiring a better understanding of these interactions to enhance the lifetime in these load regimes and improve lifetime calculations. Although it is possible to obtain crack growth rates from fatigue cracks in the lower micrometre range, further information like the exact position and type of the obstacle are mostly unavailable during the experiment. To overcome this issue, we propose a testing methodology of fatigue crack growth in micro specimens, which allows for an exact positioning of the crack relative to the obstacles and for monitoring the crack behaviour in a scanning electron microscope. The capabilities of this method are demonstrated for the interaction of fatigue cracks with grain boundaries

Investigations for Ergonomic Presentation of AIS Symbols on ECDIS

Empirical investigations were carried out in a research project for the German Federal Ministry of Transport, Building, and Housing to evaluate the presentation of AIS target information on ECDIS. The investigations were performed at three international simulation centres. The features, colour and fillingjsize of AIS symbols, as well as the influence of the ECDIS display category on the detection of AIS targets were the main issues of the investigations. Results show that blue (5-52 colour token RE5BL) is the most suitable colour of the tested colours for the presentation of AIS targets under all ambient light conditions on the tested IHO S-52 colour tables.Las investigaciones empfricas fueron llevadas a cabo en un proyecto de investigacion para el Ministerio Federal Aleman de Transporte, Construccion y Vivienda para evaluar la presentacion de la informacion de objetos del AIS en el ECDIS. Se emprendieron investigaciones en tres centros de simulacion intemacionales. Las caracterfsticas, color y tamaino de los simbolos del AIS, asi como la influencia de la categoria de la presentacion ECDIS en la deteccion de objetos del AIS fueron los temas principales de las investigaciones. Los resultados muestran que el azul (muestras del color RESBL de la S-52) es el color mas apropiado de entre los colores puestos a prueba, para la presentacion de los objetos del AIS bajo todas las condiciones de luz ambiente en las tablas de colores puestos a prueba de la S-52 de la OHI.Des investigations empiriques ant ete effectuees dans le cadre d'un projet de recherche du Ministere federal allemand des Transports, de la Construction et du logement, en vue d'evaluer la presentation des informations cibles des systemes AIS sur les ECDIS. Ces investigations ont ete effectuees dans trois centres de simulation intemationaux. La couleur des elements et la teinte /la taille des signes conventionnels des AIS, ainsi que l'influence de la categorie d'affichage de l'ECDIS sur la detection des cibles AIS ant constitue les principaux themes des investigations. Les resultats ant montre que le bleu (code de couleur RE5BL dans la S52) est la couleur la plus appropriee parmi celles testees pour la presentation des cibles AIS sous toutes les conditions ambiantes de lumiliere dans le cadre des tables de couleur testees de la S52 de l'OHI

Effect of Pretreatment on Interface Stability and Morphology of Ni/Al Hybrid Foams by in situ Microcantilever Fracture Experiment

Ni/Al hybrid foams are a new class of innovative cellular composite materials consisting of open-cell aluminium (Al) foams electrochemically coated with nanocrystalline nickel (Ni). They may be used for lightweight construction elements or as crash energy absorbers. The Ni coating strengthens the Al foam achieving an up to ten times higher energy absorption capacities compared to the Al basis foam. Cellular materials such as foams provide a strong structure-property relationship as the macroscopic material properties strongly depend on the strut geometry and the material properties of the individual struts. The interface stability between the coating and the substrate foam is the dominant contribution in the strengthening mechanism of Ni/Al hybrid foams. Hence, micromechanical characterization is an important task for the design of components made of Ni/Al hybrid foams. A strong interface corresponds to a shear-stiff connection between substrate foam and coating, whereas a soft interface allows sliding between the two phases and hence reduces the buckling stiffness of individual foam struts resulting in lower strength and energy absorption capacity of the macroscopic foam. An increased critical energy release rate for interface cracking was revealed by in situ microcantilever bending tests prepared by focused ion beam (FIB) during bending tests in the scanning electron microscope (SEM) after the chemical pretreatment of the base foam

Assessing the intergranular crack initiation probability of a grain boundary distribution by an experimental misalignment study of adjacent slip systems

Crack initiation at grain boundaries due to blocked slip transfer of dislocations is a main failure mechanism during the fatigue of metals. A quantification of the resistance effect of a grain boundary is needed to assess a textured or texture-free microstructure for fatigue strength. Geometric approaches based on the misalignment of slip systems in adjacent grains are widely used. Hence, we validated the geometric transmission factor of Shen et al. in coarse-grained high-purity aluminum under the assumption that the combination of a large slip activity and a blocked slip at a grain boundary leads to intergranular crack initiation and revealed that a detailed knowledge of the 3D-orientation of the grain boundary is essential. Thereby we gathered information about the 3D-microstructure using FIB-cross-sectioning. Hence it is possible to evaluate potential crack initiation sites for a specific microstructure or to estimate the fatigue strength of a textured microstructure in terms of a crack initiation probability

Numerical investigation of localization and suppression of thermal decomposition of forest combustible materials using specialized water supply

The danger of forest fires and their large-scale consequences are becoming ever more complex problems for mankind every year. The results of numerical studies of heat transfer processes under suppressing the thermal decomposition reaction of forest combustible materials by films and groups of water droplets are presented. We used forest combustible materials, typical for the Siberian region. We have established the relationship between the dimensions of the heated near-surface layer of the material and the thickness of the film layer of the liquid that evaporated when the thermal decomposition reaction was suppressed in forest combustible materials. Typical times of suppression of the thermal decomposition reaction of typical forest combustible materials are given when the water film on the surface evaporates. The influence of the mutual arrangement of droplets on the surface of the forest combustible material and the temperature of the outer vapor-gas mixture on the times of suppression of its pyrolysis is revealed. The results can be used to develop technologies for extinguishing fires, containment of flame sources and combustion front

Програма, методичні вказівки та контрольні завдання з дисципліни "Сучасні технології вина і коньяку"

Дисципліна "Сучасні технології вина і коньяку" входить до складу рекомендованого переліку навчальних дисциплін нормативної частини освітньо-професійної програми підготовки магістрів спеціальності 181 "Харчові технології", спеціалізації "Технології продуктів бродіння і виноробства". Предметом вивчення навчальної дисципліни "Сучасні технології вина і коньяку" є технологія виноградних та плодово-ягідних вин, коньяків, бренді та інших міцних напоїв, схеми технохімічного і мікробіологічного контролю, методики визначення якісних показників сировини, основних і допоміжних матеріалів, напівпродуктів, готової продукції, вторинних продуктів виноробства й оцінювання їх відповідності вимогам чинної нормативної документації, методики розрахунку продуктів, основних і допоміжних матеріалів, втрат і відходів виробництва. Метою викладання начальної дисципліни "Сучасні технології вина і коньяку" є формування у студентів системи навичок для здійснення ефективної професіональної діяльності на підприємствах виноробної галузі та у наукових закладах в умовах ринкової економіки, технічного переоснащення й удосконалення підприємств, застосування сучасних інноваційних технологій на основі творчого об’єднання і впровадження у виробництво отриманих знань з фундаментальних, загальноінженерних, економічних та спеціальних дисциплін, забезпечення випуску високоякісної продукції з гарантованим ступенем безпеки для людини і навколишнього середовища, оптимальними питомими витратами людської праці, матеріальних та енергетичних ресурсів

Ni/Al-Hybrid Cellular Foams: An Interface Study by Combination of 3D-Phase Morphology Imaging, Microbeam Fracture Mechanics and In Situ Synchrotron Stress Analysis

Nickel(Ni)/aluminium(Al) hybrid foams are Al base foams coated with Ni by electrodeposition. Hybrid foams offer an enhanced energy absorption capacity. To ensure a good adhering Ni coating, necessary for a shear resistant interface, the influence of a chemical pre-treatment of the base foam was investigated by a combination of an interface morphology analysis by focused ion beam (FIB) tomography and in situ mechanical testing. The critical energy for interfacial decohesion from these microbending fracture tests in the scanning electron microscope (SEM) were contrasted to and the results validated by depth-resolved measurements of the evolving stresses in the Ni coating during three-point bending tests at the energy-dispersive diffraction (EDDI) beamline at the synchrotron BESSY II. Such a multi-method assessment of the interface decohesion resistance with respect to the interface morphology provides a reliable investigation strategy for further improvement of the interface morphology