| 1. |
- Lloyd-Spets, Anita, et al.
(författare)
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MISiCFET chemical gas sensors for high temperature and corrosive environment applications
- 2002
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 389-3, s. 1415-1418
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Tidskriftsartikel (refereegranskat)abstract
- A chemical gas sensor based on a silicon carbide field effect transistor with a catalytic gate metal has been under development for a number of years. The buried gate design allows the sensor to operate at high temperatures, routinely up to 600degreesC and for at least three days at 700degreesC. The chemical inertness of silicon carbide makes it a suitable sensor technology for applications in corrosive environments such as exhaust gases and flue gases from boilers. The selectivity of the sensor devices is established through the choice of type and structure of the gate metal as well as the operation temperature. In this way NH3 sensors with low cross sensitivity to NOx have been demonstrated as potential sensors for control of selective catalytic reduction (SCR) of NOx by urea injection into diesel exhausts. The hardness of the silicon carbide makes it for example more resistant to water splash at cold start of a petrol engine than existing technologies, and a sensor which can control the air to fuel ratio, before the exhaust gases are heated, has been demonstrated. Silicon carbide sensors are also tested in flue gases from boilers. Efficient regulation of the combustion in a boiler will decrease fuel consumption and reduce emissions.
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| 2. |
- Lloyd-Spets, Anita, et al.
(författare)
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SiC based field effect gas sensors for industrial applications
- 2001
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Ingår i: Physica status solidi. A, Applied research. - 0031-8965 .- 1521-396X. ; 185:1, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- The development and field-testing of high-temperature sensors based on silicon carbide devices have shown promising results in several application areas. Silicon carbide based field-effect sensors can be operated over a large temperature range, 100-600 degreesC, and since silicon carbide is a chemically very inert material these sensors can be used in environments like exhaust gases and flue gases from boilers. The sensors respond to reducing gases like hydrogen, hydrocarbons and carbon monoxide. The use of different temperatures, different catalytic metals and different structures of the gate metal gives selectivity to different gases and arrays of sensors can be used to identify and monitor several components in gas mixtures. MOSFET sensors based on SIC combine the advantage of simple circuitry with a thicker insulator, which increases the long term stability of the devices. In this paper we describe silicon carbide MOSFET sensors and their performance and give: examples of industrial applications such as monitoring of car exhausts and flue gases. Chemometric methods have been used for the evaluation of the data.
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| 3. |
- Azevedo, Flavio, et al.
(författare)
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Social and moral psychology of COVID-19 across 69 countries
- 2023
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Ingår i: Scientific Data. - : NATURE PORTFOLIO. - 2052-4463. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behaviour change. To help scholars better understand the social and moral psychology behind public health behaviour, we present a dataset comprising of 51,404 individuals from 69 countries. This dataset was collected for the International Collaboration on Social & Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of moral and psychological measures and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours; identity and social attitudes; ideology; health and well-being; moral beliefs and motivation; personality traits; and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
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| 4. |
- Van Bavel, Jay J., et al.
(författare)
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National identity predicts public health support during a global pandemic
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding collective behaviour is an important aspect of managing the pandemic response. Here the authors show in a large global study that participants that reported identifying more strongly with their nation reported greater engagement in public health behaviours and support for public health policies in the context of the pandemic. Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
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| 5. |
- Wingbrant, Helena, et al.
(författare)
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MISiCFET chemical sensors for applications in exhaust gases and flue gases
- 2002
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 433-4, s. 953-956
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Tidskriftsartikel (refereegranskat)abstract
- A chemical gas sensor based on a silicon carbide field effect transistor with a catalytic gate metal has been under development for a number of years. The choice of silicon carbide as the semiconductor material allows the sensor to operate at high temperatures, for more than 6 months in flue gases at 300degreesC and for at least three days at 700degreesC. The chemical inertness of silicon carbide and a buried gate design makes it a suitable sensor technology for applications in corrosive environments such as exhaust gases and flue gases from boilers. The selectivity of the sensor devices is established through the choice of type and structure of the gate metal as well as the operation temperature. In this way NH3 sensors with low cross sensitivity to NOx have been demonstrated as potential sensors for control of selective catalytic reduction (SCR) of NOx by urea injection into diesel exhausts. Here we show that sensors with a porous platinum or iridium gate show different temperature ranges for NH3 detection. The hardness of the silicon carbide makes it for example more resistant to water splash at cold start of a petrol engine than existing technologies, and a sensor which can control the air to fuel ratio, before the exhaust gases are heated, has been demonstrated. Silicon carbide sensors are also tested in flue gases from boilers. Efficient regulation of the combustion in a boiler will decrease fuel consumption and reduce emissions.
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| 6. |
- Kish, L.B., et al.
(författare)
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In situ electrical transport measurements and self-organization in gold nanoparticle films during and after deposition
- 2001
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Ingår i: Surface & Coatings Technology. - 0257-8972 .- 1879-3347. ; 142-144, s. 1088-1093
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Tidskriftsartikel (refereegranskat)abstract
- In the first part of this paper, a new method is shown which is able to predict the particle size of conductive nanoparticle films in situ, during deposition. The method is used for the measurement of the time-derivative of conductance fluctuations during deposition. The second part of the paper deals with in situ conductance measurements on gold films during deposition. During the measurement, various electrical fields have been applied in order to study the possible influence of the field magnitude on the film formation. The observed effects have been interpreted by the biased percolation model. A possible technological application of the observed phenomenon is the fabrication of nanoparticle films with controlled disorder, e.g. in chemical sensors. © 2001 Elsevier Science B.V. All rights reserved.
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| 7. |
- Savage, S, et al.
(författare)
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SiC based gas sensors and their applications
- 2000
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 353-3, s. 747-752
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Tidskriftsartikel (refereegranskat)abstract
- The development and field-testing of hardy high-temperature sensors based on silicon carbide devices has to date shown promising results in several application areas. As the need to take care of the environment becomes more urgent, these small and relatively cheap sensors could be used to increase the monitoring of gases, or to replace or complement larger and more expensive sensor technologies used today. In this paper the development of Silicon Carbide MOSFET transistor sensors and Schottky diode sensors is described. The devices are tested in industrial applications such as monitoring of car exhausts and flue gases.
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| 8. |
- Skoglund, P, et al.
(författare)
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Constitutive modelling and mechanical properties of a nitrogen alloyed steel
- 2000
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Ingår i: Journal de Physique IV. - 1155-4339 .- 1764-7177. ; 10:P9, s. 701-706
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical behaviour of a nitrogen alloyed steel has been investigated. Tensile tests have been done at nominal strain rates from 10(-3) to 800 s(-1). The results are discussed in terms of material modelling and constitutive parameters for the Johnson and Cook model are proposed. At large strain rates the effect of adiabatic heating complicates the evaluation of the model constants. It is shown that significant errors in the predicted flow stress may occur if parameters determined under adiabatic conditions are used for isothermal deformation modes, or vice versa. The effect of temperature increase during the uniform part of the deformation is further discussed, and a simple finite element model for calculation of the temperature evolution with strain and strain rate is presented. The results are incorporated in the Johnson and Cook model, thus improving the agreement between model prediction and experimental data.
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