| 1. |
- Batalovic, K., et al.
(författare)
-
Origin of photocatalytic activity enhancement in Pd/Pt-deposited anatase N-TiO2 – experimental insights and DFT study of the (001) surface
- 2020
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 22:33, s. 18536-18547
-
Tidskriftsartikel (refereegranskat)abstract
- In pursuit of the ideal photocatalyst, cheap and stable semiconductor TiO(2)is considered to be a good choice if one is able to reduce its band gap and decrease the recombination rate of charge carriers. The approach that offers such improvements for energy conversion applications is the modification of TiO(2)with nitrogen and noble metals. However, the origin of these improvements and possibilities for further design of single-atom catalysts are not always straightforward. To shed light on the atomic-scale picture, we modeled the nitrogen-doped (001) anatase TiO(2)surface as a support for palladium and platinum single-atom deposition. The thermodynamics of various synthesis routes for Pd/Pt deposition and nitrogen doping is considered based on density functional theory (DFT)-calculated energies, highlighting the effect of nitrogen doping on metal dimer formation and metal-support interaction. XPS analysis of the valence band of the modified TiO(2)nanocrystals, and the calculated charge transfer and electronic structure of single-atom catalysts supported on the (001) anatase TiO(2)surface provide an insight into modifications occurring in the valence zone of TiO(2)due to nitrogen doping and Pd/Pt deposition at the surface. DFT results also show that substitutional nitrogen doping significantly increases metal-support interaction, while interstitial nitrogen doping promotes only Pt-support interaction.
|
|
| 2. |
- Flynn, M. J., et al.
(författare)
-
Moving from Petaflops to Petadata
- 2013
-
Ingår i: Communications of the ACM. - : Association for Computing Machinery (ACM). - 0001-0782 .- 1557-7317. ; 56:5, s. 39-42
-
Forskningsöversikt (refereegranskat)abstract
- The race to build ever-faster supercomputers is on, with more contenders than ever before. However, the current goals set for this race may not lead to the fastest computation for particular applications. A creator of the TOP500 supercomputers list rightfully claimed the list sheds light on only one dimension of modern supercomputing, which is a relatively narrow one. This Viewpoint is intended to induce thinking about alternative performance measures for ranking, possibly ones with a much wider scope. This Viewpoint is not offering a solution. It is offering a theme for brainstorming. To demonstrate this need for such thinking, one will use the example of a particular type of systems, based on a kind of dataflow approach. The current era of supercomputing is referred to as the petascale era. The next big HPC challenge is to break the exascale barrier. However, due to technological limitations, there is growing agreement that reaching this goal will require a substantial shift toward hardware/software codesign.
|
|
| 3. |
- Moreno, N. R., et al.
(författare)
-
CCID5 : An implementation of the BBR congestion control algorithm for DCCP and its impact over multi-path scenarios
- 2021
-
Ingår i: ANRW 2021 - Proceedings of the 2021 Applied Networking Research Workshop. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450386180 ; , s. 52-58
-
Konferensbidrag (refereegranskat)abstract
- Providing multi-connectivity services is an important goal for next generation wireless networks, where multiple access networks are available and need to be integrated into a coherent solution that efficiently supports both reliable and non reliable traffic. Based on virtual network interfaces and per path congestion controlled tunnels, the MP-DCCP based multiaccess aggregation framework presents a novel solution that flexibly supports different path schedulers and congestion control algorithms as well as reordering modules. The framework has been implemented within the Linux kernel space and has been tested over different prototypes. Experimental results have shown that the overall performance strongly depends upon the congestion control algorithm used on the individual DCCP tunnels, denoted as CCID. In this paper, we present an implementation of the BBR (Bottleneck Bandwidth Round Trip propagation time) congestion control algorithm for DCCP in the Linux kernel. We show how BBR is integrated into the MP-DCCP multi-access framework and evaluate its performance over both single and multi-path environments. Our evaluation results show that BBR improves the performance compared to CCID2 (TCPlike Congestion Control) for multi-path scenarios due to the faster response to changes in the available bandwidth, which reduces latency and increases performance, especially for unreliable traffic. The MP-DCCP framework code, including the new CCID5 is available as OpenSource1.
|
|
