| 1. |
- Birdsong, Björn K., et al.
(författare)
-
Large-scale synthesis of 2D-silica (SiOx) nanosheets using graphene oxide (GO) as a template material
- 2023
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 15:31, s. 13037-13048
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) was used in this study as a template to successfully synthesize silicon oxide (SiOx) based 2D-nanomaterials, adapting the same morphological features as the GO sheets. By performing a controlled condensation reaction using low concentrations of GO (<0.5 wt%), the study shows how to obtain 2D-nanoflakes, consisting of GO-flakes coated with a silica precursor that were ca. 500 nm in lateral diameter and ca. 1.5 nm in thickness. XPS revealed that the silanes had linked covalently with the GO sheets at the expense of the oxygen groups present on the GO surface. The GO template was shown to be fully removable through thermal treatment without affecting the nanoflake morphology of the pure SiOx-material, providing a methodology for large-scale preparation of SiOx-based 2D nanosheets with nearly identical dimensions as the GO template. The formation of SiOx sheets using a GO template was investigated for two different silane precursors, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS), showing that both precursors were capable of accurately templating the graphene oxide template. Molecular modeling revealed that the choice of silane affected the number of layers coated on the GO sheets. Furthermore, rheological measurements showed that the relative viscosity was significantly affected by the specific surface area of the synthesized particles. The protocol used showed the ability to synthesize these types of nanoparticles using a common aqueous alcohol solvent, and yield larger amounts (∼1 g) of SiOx-sheets than what has been previously reported.
|
|
| 2. |
|
|
| 3. |
- Jebali, R., et al.
(författare)
-
A first comparison of the responses of a He-4-based fast-neutron detector and a NE-213 liquid-scintillator reference detector
- 2015
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 794, s. 102-108
-
Tidskriftsartikel (refereegranskat)abstract
- A first comparison has been made between the pulse-shape discrimination characteristics of a novel He-4-based pressurized scintillation detector and a NE-213 liquicl-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquicl-scintillator reference cell produced a wide range of scintillation-light yields in response to he gamma-ray field of the source. In stark contrast, clue to the size and pressure of the He-4 gas volume, the He-4-based detector registered a maximum scintillation-light yield of 750 keV(ee) to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750 keV(ee) was excellent in the case of the He-4-based detector. Above 750 keV(ee) its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced. (C) 2015 The Authors. Published by Elsevier B.V.
|
|
| 4. |
- Kirstein, Oliver, et al.
(författare)
-
Neutron position sensitive detectors for the ESS
- 2014
-
Ingår i: Proceedings of Science. - : Proceedings of Science (PoS). ; Vertex2014, s. 029-029
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials. It will be a long pulse source, with an average beam power of 5 MW delivered to the target station. The ESS is in the construction phase, which started in 2013 with the completion of the Technical Design Report (TDR). The instruments are being selected from conceptual proposals submitted by groups from around Europe. These instruments present numerous challenges for detector technology in the absence of the availability of Helium-3, which is the default choice for detectors for instruments built until today and due to the extreme rates expected across the ESS instrument suite. Additionally a new generation of source requires a new generation of detector technologies to fully exploit the opportunities that this source provides. To meet this challenge at a green-field site, the detectors will be sourced from partners across Europe through numerous in-kind arrangements; a process that is somewhat novel for the neutron scattering community. This contribution presents briefly the current status of detectors for the ESS, and outlines the timeline to completion. For a conjectured instrument suite based upon instruments recommended for construction, a recently updated snapshot of the current expected detector requirements is presented. A strategy outline as to how these requirements might be tackled by novel detector developments is shown. In terms of future developments for the neutron community, synergies should be sought with other disciples, as recognized by various recent initiatives in Europe, in the context of the fundamentally multi-disciplinary nature of detectors. This strategy has at its basis the in-kind and collaborative partnerships necessary to be able to produce optimally performant detectors that allow the ESS instruments to be world-leading. This foresees and encourages a high level of collaboration and interdependence at its core, and rather than each group being all-rounders in every technology, the further development of centres of excellence across Europe for particular technologies and niches.
|
|
| 5. |
- Neubauer, Björn, et al.
(författare)
-
A new thermally activated battery cell-based forest fire detection and monitoring system
- 2012
-
Ingår i: WIT Transactions on Ecology and the Environment. - Southampton : WIT Press. - 9781845645847 ; , s. 113-124
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Detection of forest wildfires at early stages can significantly improve the success of fire fighting and thus it contributes to the damage and cost reduction. Surface deployed sensor networks linked to global nets are often regarded as technically simple options to achieve forest fire detection and progress monitoring. Straightforward solutions with sensor nodes continuously supplying telemetric information demand heavy duty power supplies and periodic service. They are relatively expensive and commonly not environmentally friendly. We have suggested and currently develop an early warning forest fire detection system based on inexpensive, dormant fire-activated detecting sensors and a number of monitoring nodes in a network configuration. Small deploy-and-forget type sensors contain a radio transmitter with recorded identity number, together with an inactive power element. When activated by high temperature of a developing wildfire, this element produces enough power to support the transmitter, broadcasting the unique identity code until the sensor is completely burnt. Monitoring nodes of such system stand by for sensor activation and forward the alarm information along the monitoring nodes network. Implementation of anti-collision transmission protocols in the sensors allows the monitoring nodes to keep track of fire development and progress. Monitoring nodes and nodes linking the forest fire detection and monitoring net to public networks can be made using conventional technology and utilizing existing communication networks. Thus significant efforts have been directed to the design of the primary sensors, designing them to be cost efficient and minimizing their environmental impact. Cellulose-based materials are widely used in the sensor construction to decrease its environmental impact and cost. The core of the sensor power element is made of laminated and screen-printed cellulose- based substrates. The power element is activated by a small amount of water, trapped in crystal hydrate salts in storage and released by elevated temperatures of the fire. These salt-based sensors can be manufactured in a rollto- roll manner, making them cost effective. Absence of any liquids or gels in the sensor construction will guarantee a good shelf time. © 2012 WIT Press.
|
|
| 6. |
- Nilsson, Olof, et al.
(författare)
-
The Servicitization of peer production : Reflections on the Open Source Software experience
- 2008
-
Ingår i: IFIP, Volume 267, Information Technology in the Service Economy. - New York : Springer. - 9780387097671 - 0387097678 - 9780387097688 ; , s. 353-355
-
Konferensbidrag (refereegranskat)abstract
- The concept of what Yochai Benkler called “peer production” as an alternative mechanism to traditional hierarchies and markets has captured the imagination of numerous communities in contexts ranging from t-shirt design to software to gold mining. While some question the suitability and potential longevity of this mode of production, others are focused on determining ways in which peer-produced products and services can be suitably packaged to meet the requirements of consumers. In particular, the mature peer production phenomenon known as open source software has emerged as a credible alternative to its proprietary counterpart and presents a compelling challenge to both industry and academia as we seek to understand how firms and other organizations can build sustainable business models leveraging the public commons of open source products and the collaborative engine that created them.
|
|
| 7. |
|
|
| 8. |
- Reifarth, R., et al.
(författare)
-
Nuclear astrophysics with radioactive ions at FAIR
- 2016
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
-
Konferensbidrag (refereegranskat)abstract
- The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
|
|
