| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Unsalan, Ozan, et al.
(författare)
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The Sariçiçek howardite fall in Turkey : Source crater of HED meteorites on Vesta and impact risk of Vestoids
- 2019
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Ingår i: Meteoritics and Planetary Science. - Hoboken : John Wiley & Sons. - 1086-9379 .- 1945-5100. ; 54:5, s. 953-1008
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Tidskriftsartikel (refereegranskat)abstract
- The Sariçiçek howardite meteorite shower consisting of 343 documented stones occurred on September 2, 2015 in Turkey and is the first documented howardite fall. Cosmogenic isotopes show that Sariçiçek experienced a complex cosmic‐ray exposure history, exposed during ~12–14 Ma in a regolith near the surface of a parent asteroid, and that an ~1 m sized meteoroid was launched by an impact 22 ± 2 Ma ago to Earth (as did one‐third of all HED meteorites). SIMS dating of zircon and baddeleyite yielded 4550.4 ± 2.5 Ma and 4553 ± 8.8 Ma crystallization ages for the basaltic magma clasts. The apatite U‐Pb age of 4525 ± 17 Ma, K‐Ar age of ~3.9 Ga, and the U,Th‐He ages of 1.8 ± 0.7 and 2.6 ± 0.3 Ga are interpreted to represent thermal metamorphic and impact‐related resetting ages, respectively. Petrographic; geochemical; and O‐, Cr‐, and Ti‐isotopic studies confirm that Sariçiçek belongs to the normal clan of HED meteorites. Petrographic observations and analysis of organic material indicate a small portion of carbonaceous chondrite material in the Sariçiçek regolith and organic contamination of the meteorite after a few days on soil. Video observations of the fall show an atmospheric entry at 17.3 ± 0.8 km s−1 from NW; fragmentations at 37, 33, 31, and 27 km altitude; and provide a pre‐atmospheric orbit that is the first dynamical link between the normal HED meteorite clan and the inner Main Belt. Spectral data indicate the similarity of Sariçiçek with the Vesta asteroid family (V‐class) spectra, a group of asteroids stretching to delivery resonances, which includes (4) Vesta. Dynamical modeling of meteoroid delivery to Earth shows that the complete disruption of a ~1 km sized Vesta family asteroid or a ~10 km sized impact crater on Vesta is required to provide sufficient meteoroids ≤4 m in size to account for the influx of meteorites from this HED clan. The 16.7 km diameter Antionia impact crater on Vesta was formed on terrain of the same age as given by the 4He retention age of Sariçiçek. Lunar scaling for crater production to crater counts of its ejecta blanket show it was formed ~22 Ma ago.
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| 3. |
- Tallaksen, Joel, et al.
(författare)
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Nitrogen fertilizers manufactured using wind power : greenhouse gas and energy balance of community-scale ammonia production
- 2015
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 107, s. 626-635
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents a cradle-to-gate life cycle assessment of production of ammonia using wind power. The ammonia is intended to substitute for nitrogen fertilizer produced from fossil resources. The studied system is designed to supply a rural community with fertilizer based on renewable energy and is, therefore, smaller than industrial fossil ammonia production systems. Two contrasting cases examine the impact of the location of the system, investigating the dependence on the regional energy system (background system) to balance demand and supply of energy in the ammonia production system (foreground system). The results show that wind-based ammonia production can significantly decrease fossil energy inputs and greenhouse gas emissions compared to conventional production, but that the use of energy from the background system severely impacts the environmental performance, especially in regions where fossil fuels dominate the energy system.
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| 4. |
- Zak, Audrey, 1990, et al.
(författare)
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20 μm gate width CVD graphene FETs for 0.6 THz detection
- 2014
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; , s. Art. no. 6956250-
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Konferensbidrag (refereegranskat)abstract
- We have fabricated 20 μm gate width graphene field effect transistors (GFETs) based on graphene grown by chemical vapor deposition (CVD). These GFETs are integrated with split bow-tie antennae for room temperature, direct detection of a 0.6 THz signal. Our detectors reach a maximum optical responsivity of 3.0 V/W and a minimum noise-equivalent power (NEP) of 700 pW/Hz^0.5. The successful demonstration of THz detection using CVD graphene introduces the possibility for scalable detector production.
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| 5. |
- Bauer, Maris, et al.
(författare)
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Terahertz detection with graphene field-effect transistors
- 2015
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Ingår i: Graphene Week 2015.
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Konferensbidrag (refereegranskat)abstract
- Detectors for quasi-optical and guide THz waves are key elements of any THz technology. In recent years, there has been much progress in their development. Notably, field-effect transistors (FETs) have been shown to be well suited for detector implementation at room temperature exploiting (self-)mixing effects in their channels [1]. They reach a typical noise-equivalent power (NEP) of several tens of pW/Hz^1/2 at 0.6 THz in CMOS and other technologies. First focal-plane arrays and cameras have been implemented. Frequency coverage to at least 5 THz has been demonstrated. Recently, this type of detection concept has been extended successfully to graphene-based FETs [2] opening the way to freely positionable THz detectors on a wide variety of substrates (also flexible plastics). We have improved the technology (see Fig. 1) [3] and reach, for GFETs on Si, an optical NEP of 150 pW/Hz^1/2 at 0.3 THz, with considerable room for improvement. An unusually strong thermoelectric contribution has been identified [2, 3] which may help to engineer enhanced detector performance.
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| 6. |
- Bauer, Maris, et al.
(författare)
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The potential for sensitivity enhancement by the thermoelectric effect in carbon-nanotube and graphene Tera-FETs
- 2015
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 647:1, s. UNSP 012004-
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Konferensbidrag (refereegranskat)abstract
- We report on terahertz (THz) measurements with graphene field-effect transistors with integrated antennas (Tera-FETs) lay special emphasis on thermoelectric contributions to the detected THz photoresponse. Graphene Tera-FETs with integrated broad-band bow-tie antennas were fabricated in a CVD-based growth process and were successfully applied for detection at 600 GHz with optical NEPs down to 515 pW/Hz^1/2. While rectification of THz radiation by (distributed) resistive mixing of charge-density waves induced in the gated transistor channel region is well known, significant additional contributions to the detected signal have experimentally been observed and hot-carrier thermoelectric effects have been identified as a possible origin of these signals. We also observe similar signal contributions in carbonnanotube transistors.
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| 7. |
- Zak, Audrey, 1990, et al.
(författare)
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Antenna-integrated 0.6 THz FET direct detectors based on CVD graphene
- 2014
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 14:10, s. 5834-5838
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Tidskriftsartikel (refereegranskat)abstract
- We present terahertz (THz) detectors based on top-gated graphene field effect transistors (GFETs) with integrated split-bow-tie antennas. The GFETs were fabricated using graphene grown by chemical vapor deposition (CVD). The THz detectors are capable of room-temperature rectification of a 0.6 THz signal and achieve a maximum optical responsivity better than 14 V/W and minimum optical noise-equivalent power (NEP) of 515 pW/Hz^0.5. Our results are a significant improvement over previous work on graphene direct detectors and are comparable to other established direct detector technologies. This is the first time room-temperature direct detection has been demonstrated using CVD graphene, which introduces the potential for scalable, wafer-level production of graphene detectors.
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| 8. |
- Andersson, Alf, et al.
(författare)
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Inline Process Control – a concept study of efficient in-line process control and process adjustment with respect to product geometry
- 2016
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Ingår i: Swedish Production Symposium 2016 SPS 2016. - Lund, Sweden.
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Konferensbidrag (refereegranskat)abstract
- All manufacturing processes have variation which may violate the fulfillment of assembly, functional, geometrical or esthetical requirements and difficulties to reach desired form in all areas. The cost for geometry defects rises downstream in the process chain. Therefore, it is vital to discover these defects as soon as they appear. Then adjustments can be done in the process without losing products or time. In order to find a solution for this, a project with the overall scope “development of an intelligent process control system” has been initiated. This project consists of five different work packages: Inline measurement, Process Evaluation, Corrective actions, Flexible tooling and demonstrator cell. These work packages address different areas which are necessary to fulfill the overall scope of the project. The system shall both be able to detect geometrical defects, propose adjustments and adjust simple process parameters. The results are demonstrated in a demo cell located at Chalmers University of Technology. In the demonstrator all the different areas have been verified in an industrial case study – assembly of GOR Volvo S80. Efficient offline programming for robot based measurement, efficient process evaluation based on case base reasoning (CBR) methodology, flexible fixtures and process adjustments based on corrective actions regarding in going part positioning.
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| 9. |
- McGinn, Steven, et al.
(författare)
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New Technologies for DNA analysis-A review of the READNA Project.
- 2016
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Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784.
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Forskningsöversikt (refereegranskat)abstract
- The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received funding from the European Commission for 4 1/2 years. The objectives of the project revolved around technological developments in nucleic acid analysis. The project partners have discovered, created and developed a huge body of insights into nucleic acid analysis, ranging from improvements and implementation of current technologies to the most promising sequencing technologies that constitute a 3(rd) and 4(th) generation of sequencing methods with nanopores and in situ sequencing, respectively.
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| 10. |
- Bauer, Margit, et al.
(författare)
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Assessment of the in vivo biomechanical properties of the human uterine cervix in pregnancy using the aspiration test A feasibility study
- 2009
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Ingår i: European Journal of Obstetrics, Gynecology, and Reproductive Biology. - : Elsevier BV. - 0301-2115 .- 1872-7654. ; 144, s. S77-S81
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To date no diagnostic tool is yet available to objectively assess the in vivo biomechanical properties of the uterine cervix during gestation. Methods: We show the first clinical application of an aspiration device to assess the in vivo biomechanical properties of the cervix in pregnancy with the aim to describe the physiological biomechanical changes throughout gestation in order to eventually detect pregnant women at risk for cervical insufficiency (CI). Results: Out of 15 aspiration measurements, 12 produced valid results. The stiffness values were in the range between 0.013 and 0.068 bar/mm. The results showed a good reproducibility of the aspiration test. In our previous test series on non-pregnant cervices our repetitive measurements showed a standard deviation of > 20% compared to <+/- 10% to our data on pregnant cervices. Stiffness values are decreasing with gestational age which indicates a progressive softening of cervical tissue towards the end of pregnancy. Three pregnant women had two subsequent measurements within a time interval of four weeks. Decreasing stiffness values in the range of 20% were recorded. Discussion: This preliminary study on the clinical practicability of aspiration tests showed promising results in terms of reproducibility (reliability) and clinical use (feasibility). Ongoing studies will provide further insights on its usefulness in clinical practice and in the detection of substantial changes of the cervix in pregnancy indicative for threatened preterm birth or cervical insufficiency.
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