| 1. |
- Amann, Daniel, et al.
(författare)
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Inducing Affordability?: Observations From An Experimental Study Of Concept Generation
- 2021
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Ingår i: Proceedings of the 22th CINet conference, September 12 – 14, Gothenburg, Sweden. - Enschede. - 9789077360248
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Konferensbidrag (refereegranskat)abstract
- Early preliminary concepts are claimed to have a profound impact on the final product. Since these concepts often are based on intuitive judgements, it is important that these judgements are appropriate for the desired outcome. Intuition is derived from what one brings to mind, and consequently, the access to information is important for making relevant judgements. Therefore, when a departure from a present path of development is sought for, access to new information is likely to be required. Results from an experimental study, addressing affordability and concept generation, indicated that individuals were influenced, by the provision of selective information, to make more cost considerations and even to change approach when generating new concepts. It was further recognized that weak abilities to estimate costs in a lifecycle and capability perspective likely hampered low-cost ambitions. The findings from this study are suggested to contribute to theory on product development, and to support affordability when new products are developed.
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| 2. |
- Angenendt, Knut, 1982, et al.
(författare)
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Ionic liquid structures from large DFT calculations using mindless configurations
- 2010
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:48, s. 20577-20582
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Tidskriftsartikel (refereegranskat)abstract
- Three different popular imidazolium based ionic liquids (ILs); EMI-BF4, EMI-PF6, and EMI-TFSI, have been modeled by DFT calculations (B3LYP/6-311+G*) using large, up to 130 atom cluster models, for a better understanding of the structure and ion ion interactions in these ILs and ILs in general. Particular emphasis has been put on the role of appropriate starting structures and how the present large models differ from the ion-pair models of ILs generally used. The system size normalized ion ion interaction energies are shown to converge rapidly, and conformational equilibria and higher order properties like IR spectra are shown to be valuable as quality criteria. The explicit inclusion of an IL environment by the large cluster approach is also compared to using an implicit, continuum, strategy via SCRF C-PCM calculations.
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| 3. |
- Capaci, Francesca, et al.
(författare)
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Simulating and Analyzing Experiments in the Tennessee Eastman Process Simulator
- 2015
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Ingår i: ENBIS-15.
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Konferensbidrag (refereegranskat)abstract
- In many of today’s continuous processes, the data collection is usually performed automatically yielding exorbitant amount of data on various quality characteristics and inputs to the system. Moreover, such data are usually collected at high frequency introducing significant serial dependence in time. This violates the independent data assumption of many industrial statistics methods used in process improvement studies. These studies often involve controlled experiments to unearth the causal relationships to be used for robustness and optimization purposes.However real production processes are not suitable for studying new experimental methodologies, partly because unknown disturbances/experimental settings may lead to erroneous conclusions. Moreover large scale experimentation in production processes is frowned upon due to consequent disturbances and production delays. Hence realistic simulation of such processes offers an excellent opportunity for experimentation and methodological development.One commonly used process simulator is the Tennessee Eastman (TE) challenge chemical process simulator (Downs & Vogel, 1993)[1]. The process produces two products from four reactants, containing 41 measured variables and 12 manipulated variables. In addition to the process description, the problem statement defines process constraints, 20 types of process disturbances, and six operating modes corresponding to different production rates and mass ratios in the product stream.The purpose of this paper is to illustrate the use of the TE process with an appropriate feedback control as a test-bed for the methodological developments of new experimental design and analysis techniques.The paper illustrates how two-level experimental designs can be used to identify how the input factors affect the outputs in a chemical process.Simulations using Matlab/Simulink software are used to study the impact of e.g. process disturbances, closed loop control and autocorrelated data on different experimental arrangements.The experiments are analysed using a time series analysis approach to identify input-output relationships in a process operating in closed-loop with multivariate responses. The dynamics of the process are explored and the necessary run lengths for stable effect estimates are discussed.
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| 4. |
- Carini, Giovanni, et al.
(författare)
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Hypersonic attenuation in cesium borate glasses: Relaxation and anharmonicity
- 2009
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - : Elsevier BV. - 0921-5093. ; 521-22, s. 247-250
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Konferensbidrag (refereegranskat)abstract
- The internal friction and the sound velocity in a cesium borate glass (Cs(2)O)(0.14)(B(2)O(3))(0.86) were measured at ultrasonic and hypersonic frequencies by Brillouin scattering measurements over the temperature range between 15 and 300 K. The analysis of the experimental results show that, in addition to thermally activated local motions of structural defects, the vibrational anharmonicity contributes substantially to the temperatures dependences of both the hypersonic loss and velocity. It has been also proved that above 150 K the vibrational anharmonicity appears to be governed by the Akhiezer mechanism of phonon viscosity.
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| 5. |
- Carlsson, Anna K, 1966, et al.
(författare)
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Rollator related pedestrian single accidents and collision events in Sweden
- 2022
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Ingår i: Traffic Safety Research (TSR). - : Lund University. - 2004-3082. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Rollators (four-wheel walkers in USA; zimmer frames in UK) are commonly used as mobility aids for the elderly and people with a variety of disabilities. Pedestrian rollator users are a sub-group of Vulnerable Road Users (VRUs), although this group is rarely recognised in traffic safety contexts. The aim of this study is to extract and analyse rollator related pedestrian accident and injury data in Sweden. The results will provide valuable insight into the risks and obstacles rollator users are exposed to in the traffic environment and may in the long term contribute to improving the mobility of this group. The current study is based on data from 2,020 accidents involving 2,305 persons extracted from the Swedish Traffic Accident Data Acquisition (STRADA) database. For consistency reasons, a subset of data (N = 745) was analysed in order to investigate the development of accidents over a period of 10 years. Thereafter, each accident in the whole data set was registered as either single or collision. The results show that the number of rollator accidents in Sweden increased by approximately 80% during 2007–2016. Females dominate the injury statistics of single accidents, collisions, as well as fatal outcome, which may be due to exposure and/or differences in physical characteristics. Single accidents are much more common than collisions (n=1,668 and n=352, respectively) and the injury consequences are at least as serious. Data from the present study have revealed that the frequency of minor injuries (ISS 1–3) is 4.3 times, moderate (ISS 4–8) 6.0 times and serious injuries (ISS 9–15) 8.9 times higher in single accidents than in collisions. Fatal injuries are, however, more common in collision events (33 in comparison to 8). The vast majority of single accidents (99%) was due to falls. Many of the single accidents (29%) were caused by ground level differences (typically a curb) or due to surface conditions (19%). Collisions involved cars, trucks or buses in 91% of cases, occurring predominantly in car parks (31%) and on (zebra) crossings (30%). In 54% of cases the vehicles reversed into the rollator. Abbreviated Injury Scale (AIS) 3+ injuries were dominated by head (36%) and torso (33%) injuries in collision events, and hip fractures (71%) in single accidents. The present study shows that further research into rollator user related accidents, both single accidents and collision events, is required. In order to introduce appropriate measures, future work should follow up on accident and injury developments and further improve the quality of mobility aid related accident data in general. Improved stability and design, proper training programmes, effective maintenance services, development of a supporting infrastructure would contribute to increased safety for rollator users.
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| 6. |
- Cederberg, Lennart, et al.
(författare)
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The Arctic Tern: AI + Soft Values = Save Fuel
- 2023
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Ingår i: 8th Hull Performance & Insight Conference. ; , s. 38-43
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Konferensbidrag (refereegranskat)abstract
- This paper summaries three years of technical development and research in close collaboration with several major shipping companies. Besides the technical AI-based decision support systems, the project has focused on soft values, how the support systems become efficient support for real, both ashore and onboard. It is important to create knowledge among technical-, commercial- and operation departments within the organisations on how to implement new methods. Different types of vessels operate under vastly different commercial realities that impact the performance and energy effectiveness. Technical systems must be adapted to each actor's reality to achieve a change and drive more climate-friendly transportation. The Arctic Tern shows fuel savings of 2-14%.
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| 7. |
- Chen, Zhe, et al.
(författare)
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Nano-scale characterization of white layer in broached Inconel 718
- 2017
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - Amsterdam : Elsevier BV. - 0921-5093 .- 1873-4936. ; 684, s. 373-384
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Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of white layers during broaching and their mechanical properties are not well investigated and understood to date. In the present study, multiple advanced characterization techniques with nano-scale resolution, including transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD), atom probe tomography (APT) as well as nano-indentation, have been used to systematically examine the microstructural evolution and corresponding mechanical properties of a surface white layer formed when broaching the nickel-based superalloy Inconel 718.TEM observations showed that the broached white layer consists of nano-sized grains, mostly in the range of 20–50 nm. The crystallographic texture detected by TKD further revealed that the refined microstructure is primarily caused by strong shear deformation. Co-located Al-rich and Nb-rich fine clusters have been identified by APT, which are most likely to be γ′ and γ′′ clusters in a form of co-precipitates, where the clusters showed elongated and aligned appearance associated with the severe shearing history. The microstructural characteristics and crystallography of the broached white layer suggest that it was essentially formed by adiabatic shear localization in which the dominant metallurgical process is rotational dynamic recrystallization based on mechanically-driven subgrain rotations. The grain refinement within the white layer led to an increase of the surface nano-hardness by 14% and a reduction in elastic modulus by nearly 10% compared to that of the bulk material. This is primarily due to the greatly increased volume fraction of grain boundaries, when the grain size was reduced down to the nanoscale.
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| 8. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Online Detection of H2O and CO in the Humid Raw Gas from the Gasifier Using Terahertz Spectroscopy
- 2013
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Ingår i: ICPS, 13 International Conference on Polygeneration Strategies, Sept.5-13, Vienna, Austria. - 9783950275483 ; , s. 51-58
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Konferensbidrag (refereegranskat)abstract
- The integration of a gasifier with a complex multistage synthesis process, such as SNG synthesis, demands a fast monitoring of the gasifier performance. However, despite the availability of standard analyzers for determination of dry gas composition, there are still many practical difficulties remaining in the online measurement of tar and steam in the raw gas. For the detection of steam concentration, electromagnetic waves at terahertz frequencies (102-104 GHz) are promising with regard to development of a robust online measurement device for industrial application. The main reason for the high potential is the low risk for interference with the wide range of other molecules and that the transmission of electromagnetic waves at THz frequencies is rather low sensitive to deposits and particulate matter in the course of the beam compared to the conventional and well established wavelengths like infrared. In the present work, a THz gas spectrometer was designed and constructed to check the feasibility of applying this measurement technique at industrial scale. For this purpose, continuous flows of raw gas with various water and CO contents from the Chalmers gasifier as well as a flue gas with known water content from the biomass combustor were introduced to the spectrometer set-up. H2O and CO compositions in each stream were determined in an online manner. The results confirmed the possibility of applying strong rotational water lines at 448 and 380 GHz to develop reliable devices for online measurement of water vapor with excellent error interval. However, some difficulties were encountered for simultaneous detection CO concentration with water within the frequency range studied in this work (300-500 GHz).
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| 9. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Terahertz Gas Spectrometer
- 2014
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Ingår i: Swedish Microwave Days March 11-12, 2014, Gothenburg, Sweden.
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Konferensbidrag (refereegranskat)abstract
- We present a 300-500GHz gas spectrometer built for and practically tested at the 2–4-MW indirect gasifier at the Chalmers Power Center. The primary goal is precise online measurements of H2O vapor and CO concentrations in the producer gas. Experimentally obtained H2O vapor concentration resolution was about 1% at the conditions of 50% VMR and 400 deg.C.
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| 10. |
- Chernikova, Dina, 1982, et al.
(författare)
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Testing a direct method for evaluating the concentration of boron in a fuel pool using scintillation detectors, and a 252Cf and an 241Am-Be source
- 2013
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Ingår i: Proceeding of ESARDA meeting 2013.
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Konferensbidrag (refereegranskat)abstract
- The present investigations are aimed at the development and testing of a direct non-destructive method for evaluating the concentration of boron in a fuel pool using scintillation detectors. The method uses a modified ratio between two gamma lines with energy of 480 keV and 2.23 MeV. These lines belong to the capture of a thermal neutron in boron and hydrogen, respectively. The relation between them can reveal the concentration of boron in the fuel pond.The method proposed was tested in a laboratory experiment with a 252Cf and an 241Am-Be source. EJ-309 liquid scintillation detectors were used for measurements of gamma spectra. The concentration of boron in water varied from 1550 ppm to 4200 ppm. The optimization and test studies were performed via MCNPX simulations.The results of these tests are provided in the present paper and they show that the boron content in water can be determined through using the characteristics of gamma lines with energy of 480 keV and 2.23 MeV.
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