| 1. |
- Bae, Kichang, et al.
(författare)
-
Corrosion Resistance of Laser Powder Bed Fused AISI 316L Stainless Steel and Effect of Direct Annealing
- 2022
-
Ingår i: Materials. - : MDPI. - 1996-1944. ; 15:18
-
Tidskriftsartikel (refereegranskat)abstract
- Alloy parts produced by an additive manufacturing method with rapid heat transfer from fast melting and solidification have different microstructures, characteristics, and performances compared with materials made by the conventional process. In this study, the corrosion and oxidation resistance of SS316L, which was prepared by the powder bed fusion process, was compared with those of cold-rolled SS316L. Additionally, the surface oxide film on stainless steel was thoroughly assessed since the film has the greatest influence on the corrosion and oxidation resistance. The effect of heat treatment on corrosion and oxidation resistance of SS316L fabricated by additive manufacturing was investigated. The SS316L has a microstructure formed by sub-grain cells, in which locally concentrated alloying elements form a stable passive film. As a result, it has a higher level of corrosion resistance and oxidation resistance than conventional cold-rolled materials. However, it was confirmed that the sub-grain cell was removed by heat treatment, which resulted in the degradation of corrosion and oxidation resistance.
|
|
| 2. |
- Malavelle, Florent F., et al.
(författare)
-
Strong constraints on aerosol-cloud interactions from volcanic eruptions
- 2017
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 546:7659, s. 485-491
-
Tidskriftsartikel (refereegranskat)abstract
- Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol-cloud interactions. Here we show that the massive 2014-2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets-consistent with expectations-but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around -0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response.
|
|
| 3. |
- Washington, Samuel, et al.
(författare)
-
Identifying Black Spots Using Property Damage Only Equivalency (PDOE) Factors
- 2013
-
Ingår i: Proceedings of the 16th International Conference Road Safety on Four Continents. - Linköping : Statens väg- och transportforskningsinstitut.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Methodologies for identifying ‘sites with promise’ have received considerable attention in the transportation safety literature. Robust hot spot identification (HSID) methodologies are vital as errors result in either identifying a safe site as high risk (false positive) or a high risk site as safe (false negative) misuse of public funds and lead to poor investment decisions and inefficient risk management. The historical pursuit of HSID methods development has lead to important insights; however, there remain at least several critical impediments to further progress: 1) a significant proportion of property damage only (PDO) and minor injury crashes are underreported (approximately 40%), affecting the reliability of count based models; 2) most methods ignore crash severity and costs; and 3) expected safety performance functions are heavily skewed by a preponderance of zeroes. This paper argues that it is possible and indeed desirable to incorporate crash costs into HSID. Moreover, a straightforward method is proposed whereby crashes are intelligently weighted using property damage only equivalent (PDOE) crashes. The use of PDOEs enables identification of a set of high-risk sites that reflect the true safety costs to society and simultaneously reduces the influence of under-reported PDO crashes, thereby addressing impediments 1 and 2. Non-parametric Quantile regression is used to overcome the preponderance of zeroes problem (impediment 3). The proposed procedure is illustrated using rural road segment data from Korea.
|
|
