| 1. |
- Abshirini, Ehsan, 1979-, et al.
(författare)
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Resilience, space syntax and spatialinterfaces: The case of river cities
- 2017
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Ingår i: A|Z ITU Journal of the Faculty of Architecture. - : ITU Press, Press of the Istanbul Techncial University. - 1303-7005 .- 1302-8324. ; 14:1, s. 25-41
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Tidskriftsartikel (refereegranskat)abstract
- Resilience defined as the capacity of a system to manage impacts, keep its efficiency and continue its development has been scrutinized by researchers from different points of view over the past decades. Due to the prominence of resilience in urban planning, this paper intends to find out how the spatial structure of cities deals with disturbances, and if geographical phenomena such as rivers affect the resilience in cities. Using the space syntax methods syntactically analyze the resilience in cities, we innovatively introduce two measures; similarity and sameness. These measures are in relation with the syntactical properties of cities and compare the degree of resilience between different groups. Similarity measures the degree to which each city retains the relative magnitude of its foreground network after a disturbance and sameness is the degree to which each city retains the same segments as its foreground network after a disturbance. Likewise to network resilience studies, we apply different disturbances on cities and explore the reaction of cities to disturbances in terms of size of the foreground network and which segments are parts thereof. We then compare different groups based on these measurements as a method to analyze sameness and similarity. The results show that the resilience, in the way we define it, is different in different cities depending on in which view and based on which parameters we are discussing the resilience. Additionally morphological phenomena such as rivers have a great impact on the structure of cities and in turn on their resilience.
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| 2. |
- Abshirini, Ehsan, 1979-, et al.
(författare)
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Visibility Analysis, Similarity and Dissimilarity in General Trends of Building Layouts and their Functions
- 2013
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Ingår i: Proceedings of Ninth International Space Syntax Symposium. - Seoul : Sejong University Press. - 9788986177213 ; , s. 11:1-11:15
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Konferensbidrag (refereegranskat)abstract
- Visibility analysis is one of the key methods in space syntax theory that discusses visual information conveyed to observers from any location in space that is potentially directly visible for the observer without any obstruction. Visibility – simply defined as what we can see – not only affects the spatial function of buildings, but also has visual relation to the perception of buildings by inhabitants and visitors. In this paper we intend to present the result of visibility analysis applied on a sample of building layouts of different sizes and functions from a variety of places of periods. The main aim of this paper is to statistically explore the general trends of building layouts and show if and how visibility properties such as connectivity, clustering coefficient, mean depth, entropy, and integration values can make distinctions among different functions of buildings. Our findings reveal that there are significant correlation coefficients among global properties of visibility in which we consider the mean value of properties, a similarity suggesting that they are not intensively manipulated by architecture. On the other hand, there are correlations although less so than the previous, still significant among local properties of visibility in which we consider the (max-min) value of properties, suggesting that social, cultural or other physical parameters distinguish buildings individually. We also show that functions such as ‘museum’ and ‘veterinary’ are relatively well-clustered, while functions such as ‘ancient’ and ‘shopping’ show high diversity. In addition, using a decision tree model we show that, in our sample, functions such as ‘museum’ and ‘library’ are more predictable rather than functions such as ‘hospital’ and ‘shopping.’ All of these mean that – at least in our sample – the usability and applicability of well-clustered and well-predicted functions have been predominant in shaping their interior spaces; vice versa, in well-diverse and unpredicted functions, the pragmatic solutions of people’s daily life developed in material culture affect the visual properties of their interior spaces.
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| 3. |
- Absil, Olivier, et al.
(författare)
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An update on the VORTEX project
- 2015
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Ingår i: Techniques and Instrumentation for Detection of Exoplanets VII. - : SPIE.
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Konferensbidrag (refereegranskat)abstract
- In this talk, we will review the on-going activities within the VORTEX teamat the University of Liège and Uppsala University. The VORTEX project aimsto design, manufacture, test, and exploit vector vortex phase masks madeof sub-wavelength gratings (aka the Annular Groove Phase Mask, AGPM)for the direct detection and characterization of extrasolar planets. This talkwill specifically report on the commissioning of several AGPMs on infraredcameras equipping 10-m class telescopes, including the VLT, the LBT andthe Keck. We will describe the in-lab and on-sky performance of the AGPMs,and discuss first scientific observations. We will also report on the lessonslearned from the on-sky operation of our vortices, and discuss ways toimprove their performance. The potential of our coronagraphic devices inthe context of future extremely large telescopes and space missions will alsobe addressed.
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| 4. |
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| 5. |
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| 6. |
- Aiso, Toshiharu, 1983-, et al.
(författare)
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Effect of Si and Al additions to carbon steel on material transfer and coating damage mechanism in turning with CVD coated tools
- 2016
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 368-369, s. 379-389
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Tidskriftsartikel (refereegranskat)abstract
- Material transfer from the work materials to the tools strongly influences machining performance and tool life. The influence of Si and Al additions to carbon steel on the material transfer and coating wear in turning with CVD coated carbide tools is investigated. Three model steels are specifically designed to separately study the effects of the individual alloying elements: one reference steel with C as the only alloying element (Base steel), and two steels alloyed also with 1 mass% Si or Al. In the region around the depth of cut on the rake face, where the outside edge of the chip passes over the tool surface, the coating is worn mainly by abrasion when cutting the Base steel. When cutting the Si alloyed steel, an almost pure Si–O transfer layer covers the coating surface, which protects it from wear. When cutting the Al alloyed steel, an almost pure Al–O transfer layer forms on the coating. This layer promotes steel transfer and associated adhesive wear of the coating, which rapidly results in coating detachment and eventually causes notch wear. In the crater region, only the Al alloyed steel results in a transfer layer, an AlN layer that reduces the crater wear.
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| 7. |
- Aiso, Toshiharu, 1983-, et al.
(författare)
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Effect of Si and Cr additions to carbon steel on material transfer in a steel/TiN coated tool sliding contact
- 2016
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 97, s. 337-348
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Tidskriftsartikel (refereegranskat)abstract
- A crossed cylinders sliding test, simulating the contact between the chip and the tool in machining, is used to evaluate material transfer and friction characteristics of a TiN coating against specifically designed model steels. These include one base reference, only alloyed with C (Base steel) and two alloyed also with 1 mass% Si or Cr. When sliding against the Base steel, an Fe-O layer is formed on the coating. Against the Si and Cr alloyed steels, Fe-Si-O and Fe-Cr-O layers are formed. In these oxides, Si and Cr are enriched, i.e. preferentially transferred from the steels. Compared to the Base steel, the friction coefficient is significantly lower against the Si alloyed steel and higher against the Cr alloyed steel.
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| 8. |
- Aiso, Toshiharu, 1983-, et al.
(författare)
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Influence of contact parameters on material transfer from steel to TiN coated tool : optimisation of a sliding test for simulation of material transfer in milling
- 2016
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Ingår i: Tribology - Materials, Surfaces & Interfaces. - : Informa UK Limited. - 1751-5831 .- 1751-584X. ; 10:3, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- Sliding between crossed cylinders, one large work material cylinder and one smaller coated tool cylinder, can be used to simulate the contact between a chip and the rake face of a cutting tool. However accurate simulations require the mode of material transfer in the test to match that in real machining. The mode is strongly dependent on normal load and sliding speed, and it is classified into four types; negligible oxide, only iron oxide, iron oxide and alloy oxide, and metallic transfer with coating cracking. A high load proved to be most important to accurately simulate the mode and area of material transfer occurring in milling. The diameter of the work material cylinder influences the shape of the contact mark, but has no influence on the mode of transfer. This means smaller work material diameters can favorably be used, reducing costs and facilitating handling during both tests and analysis.
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| 9. |
- Aiso, Toshiharu, 1983-, et al.
(författare)
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Influence of Mn and Al additions to carbon steel on material transfer and coating damage mechanism in a sliding contact between steel and TiN coated HSS tool
- 2016
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 101, s. 414-424
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Tidskriftsartikel (refereegranskat)abstract
- A crossed cylinders sliding test, simulating the contact between the chip and the cutting tool, is used to evaluate material transfer, friction characteristics and coating damage of a TiN coated high speed steel against specifically designed model steels. These steels include one reference with C as the only alloy element (Base steel), and two alloyed also with 1 mass% Mn or Al. When sliding against the Base steel, an Fe–O layer forms on the coating and protects it from wear. Against the Mn alloyed steel, Fe–Mn–O forms, which has no protective effect. Against the Al alloyed steel, an almost pure Al–O layer forms. This leads to the highest friction, rapidly causing substrate softening and coating fracture.
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