| 1. |
- Karlkvist, Tommy, et al.
(författare)
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Molecular recognition in mineral flotation : Selectivity in apatite-calcite system
- 2014
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Ingår i: 27th International Mineral Processing Congress, IMPC 2014, Santiago, Chile, 20-24 October 2014.
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Konferensbidrag (refereegranskat)abstract
- The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying length between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant with the same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite and calcite mineral surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ potential and infra-red spectroscopy data.
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| 2. |
- Patra, Anuttam, et al.
(författare)
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Design and development of novel mineral-specific collectors for flotation
- 2014
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Ingår i: 27th International Mineral Processing Congress, IMPC 2014, Santiago, Chile, 20-24 October 2014.
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Konferensbidrag (refereegranskat)abstract
- Almost all of the flotation reagents used today were discovered by continued application of empirical methods and/or trial and error experimentation. Moreover, with the metal-ion specific approach used so far, it is difficult to separate the minerals containing the same constituent metal ion. A critical assessment of molecular recognition processes involved in biomineralization suggested the possibility of using reagents which are surface specific. The concept that the molecules consisting of two or more functional groups having appropriate spacing between those so as to achieve structural/stereochemical compatibility during interaction with the mineral surface exhibit structure-specificity is thought to be extended to the design of specific collectors in flotation processes. In the present study, for the first time, a rational design of surface active molecules, and thereby the recognition of crystal faces (of minerals) by these molecules through structural and stereochemical matching is being utilized successfully to selectively float various minerals. For this purpose, carboxylate-based collectors (for mineral specific flotation of calcium minerals) as well as xanthate-based collectors (for mineral specific flotation of sulphide minerals) with a fixed alkyl chain length but having two functional groups with varying geometrical distances (separated by a spacer of one, two and three carbon atoms) between them have been synthesized. In this article, we have discussed the design, synthesis, purification of these novel mineral specific collectors as well as their important solution parameters in relation to flotation processes.
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| 3. |
- Ahlinder, Sven, et al.
(författare)
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A study of parameters affecting noise on a heavy duty DI engine
- 2007
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Konferensbidrag (refereegranskat)abstract
- On a 13 liter Direct Injection Heavy duty diesel engine, noise and cylinder pressure have been measured in order to investigate if noise can be estimated from cylinder pressure. The idea of filtering cylinder pressure to obtain noise has been tested. This idea implies that the engine works as a linear filter. The linear relation between cylinder pressure frequencies and noise frequencies seems quite poor and the method probably does not work on the engine tested. When measuring noise, on the other hand, multivariate low order polynomials work well to study the trade-off between measured noise, fuel consumption, NOx and Soot. This implies that the huge datasets gathered with modern electronically controlled engines can be handled this way. Copyright © 2007 Society of Automotive Engineers of Japan, Inc.
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| 4. |
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| 5. |
- Hedegärd, Marcus, 1979, et al.
(författare)
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Convex Identification of Minimal Function Bases for Cylinder Pressure by Using Pressure Values as Basis Weights
- 2019
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Ingår i: IEEE Transactions on Control Systems Technology. - 1063-6536 .- 1558-0865. ; 27:1, s. 346-354
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Tidskriftsartikel (refereegranskat)abstract
- Estimating cylinder individual pressures using flywheel angular measurements is difficult, foremost because several input signals must be estimated from one single measurement signal. Since the pressures cannot vary arbitrary, estimation can still be possible, but it leaves little room for robustness. To take most use of data and models, it is suggested here to parameterize pressures using a function basis. For a general physics-based engine model, it is shown how the information content in the angular measurement is limited, implying that only a few parameters per cylinder can be estimated. If small deviations in the combustion are to be identified, a very parameter efficient basis is, therefore, needed. By showing that the basis can be chosen such that its weights are pressures at distinct angles, a convex optimization problem to determine optimal basis functions is derived. The method is applied to extensive cylinder pressure data for a six-cylinder diesel engine in a case study with induced combustion faults. The result is that only three to four free parameters per cylinder are needed to achieve a close fit, and a provided analysis suggests that this may enable the design of robust estimators.
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| 6. |
- Höstmad, Patrik, 1974, et al.
(författare)
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Off-peak low noise heavy-duty vehicles, facade insulation and indoor noise disturbance
- 2016
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Ingår i: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering. - 9783939296119 ; , s. 5258-5266, s. 5258-5266
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Konferensbidrag (refereegranskat)abstract
- Off-peak delivery of goods can result in increased transport efficiency, fuel savings, less pollution and increased traffic safety. However, unless carefully managed it causes increased annoyance and health risks for inhabitants exposed to the transportation noise during hours used for recovery and sleep. The presented work focuses on heavy-duty vehicles with Diesel engines during the "last mile" of the transport corridor through densely populated city centers. The aim is to study preconditions, open questions, and problem areas when nighttime soundscapes are altered by low noise vehicles. By using measured and simulated sounds, different driving conditions and acoustical treatments of vehicles and facade were studied at the facade and indoors in terms of 1/3-octaveband levels and judgments in listening tests. The evaluation shows that low-frequency noise of the vehicles is important indoors, while high-frequency noise is the major contributor outdoors. According to the listening tests the low-frequency noise is coupled to the degree of reported arousal, indicating that reduced low-frequency noise is especially important at nighttime. It was concluded that an acceptable indoor environment was achieved with a modified truck that is driven by a responsible driver, and by using "noise proof" windows with higher sound insulation.
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| 7. |
- Jacobson, Jan, et al.
(författare)
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Final testing protocols
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is the final document summarizing the inspection and testing protocols of the eVALUE project. It describes principles, inspection protocols and testing protocols for performance testing of ICT-based safety systems. The inspection protocols (published earlier in D2.2) and the testing protocols introduced in D3.1 are replaced by the ones in D3.2. The older versions are obsolete and should be disregarded. The inspection protocols cover the definition of the test vehicle, HMI aspects, environmental conditions, and functional safety. The inspection protocols are used to prepare for the physical tests as well as evaluating the performance of the vehicle. The testing protocols address longitudinal, lateral, and stability-oriented traffic scenarios. The longitudinal scenarios include a pedestrian crossing the road in front of the vehicle, or the situation where a driver approaches a stationary queue of cars. Involuntarily lane departures and cars in the blind spot during a lane change are situations covered by the lateral scenarios. Exiting a highway, avoiding an obstacle, and braking on a partially ice-covered road surface are examples of traffic scenarios related to stability.
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| 8. |
- Krakhmalev, Pavel, 1973-, et al.
(författare)
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Microstructure, solidification texture, and thermal stability of 316 L stainless steel manufactured by laser powder bed fusion
- 2018
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Ingår i: Metals. - : MDPI AG. - 2075-4701. ; 8:8, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- This article overviews the scientific results of the microstructural features observed in 316 L stainless steel manufactured by the laser powder bed fusion (LPBF) method obtained by the authors, and discusses the results with respect to the recently published literature. Microscopic features of the LPBF microstructure, i.e., epitaxial nucleation, cellular structure, microsegregation, porosity, competitive colony growth, and solidification texture, were experimentally studied by scanning and transmission electron microscopy, diffraction methods, and atom probe tomography. The influence of laser power and laser scanning speed on the microstructure was discussed in the perspective of governing the microstructure by controlling the process parameters. It was shown that the three-dimensional (3D) zig-zag solidification texture observed in the LPBF 316 L was related to the laser scanning strategy. The thermal stability of the microstructure was investigated under isothermal annealing conditions. It was shown that the cells formed at solidification started to disappear at about 800 °C, and that this process leads to a substantial decrease in hardness. Colony boundaries, nevertheless, were quite stable, and no significant grain growth was observed after heat treatment at 1050 °C. The observed experimental results are discussed with respect to the fundamental knowledge of the solidification processes, and compared with the existing literature data.
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| 9. |
- Lindberg, Therese, et al.
(författare)
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Geometallurgy@LKAB
- 2013
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Ingår i: Proceedings Conference in Minerals Engineering 2013. - Luleå : Luleå tekniska universitet. - 9789174396478 ; , s. 125-136
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The area of geometallurgy is in its context not entirely new and LKAB has for ages worked according to the idea “minerals to products”, but the development especially on the instrumental analysis side the last ten years has made a geometallurgy a feasible area today. LKAB’s idea is to work quite broad, with internal educations, an active working process in ongoing projects, together with external parties (such as Luleå University of Technology), with PhD-projects and an upgrading on the instrumental side at LKAB R&D. This paper is a summary about the concept geometallurgy at LKAB and some of the actions within the framework of Geometallurgy@LKAB.
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| 10. |
- Vestin Fredriksson, Malin, et al.
(författare)
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Clinical Manifestations and Symptoms of Maxillary Sinusitis of Odontogenic Origin Demonstrated by Cone Beam Computed Tomography
- 2019
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Ingår i: Journal of General Practice. - : OMICS Publishing Group. - 2329-9126. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To compare the symptomatology of patients with maxillary sinusitis of dental origin (MSDO) with sinusitis due to upper respiratory tract infection (URTI) with a special focus on time to correct diagnosis. To define the accuracy of cone beam computed tomography (CBCT) in detecting the dental origin of the sinusitis.Methods: Retrospective review of the otolaryngology specialist care, primary health care and dental health care medical records of patients with maxillary sinusitis who has been referred for radiology. All patients were examined by CBCT, which has a better resolution regarding bony structures than low-dose computed tomography. To the best of our knowledge there is no previous study on this topic based on CBCT as diagnostic method.Results: Sixty-one patients were included in the study; of these, 25 had MSDO and 36 had URTI sinusitis. The MSDO patients more frequently reported foul odour and foul taste than patients with URTI sinusitis. The URTI sinusitis patients more frequently reported symptoms such as facial pain, facial congestion and cold-related symptoms. Both the time from the onset of symptoms to the first medical visit and the subsequent time to a correct diagnosis were significantly longer in the MSDO group. The accuracy of CBCT for detecting dental pathology as the underlying cause of sinusitis was 97%.Conclusion: The present study verifies that maxillary sinusitis of dental origin differs from viral-induced rhinosinusitis concerning symptomatology and clinical findings. Certain findings and symptoms could serve as valuable indicators of an underlying dental pathology, because although MSDO is well known, the present study shows that these patients are often misdiagnosed and the correct diagnose and treatment is often delayed several months. Consequently, better assessment is important. The suspicion of MSDO should be raised for patients with unilateral sinusitis presenting little pain, foul odour or foul taste and a long time course. These patients should be referred for radiology, preferably CBCT, to rule out odontogenic cause. CBCT is easy to perform for sinusitis examinations and has advances to common CT, especially regarding detection of pathology in bony structures as the periapical area. Because of this CBCT is a reliable tool in order to detect maxillary sinusitis of dental origin.
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