| 1. |
- Saarimäki, Jonas, et al.
(författare)
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3D Residual Stresses in Selective Laser Melted Hastelloy X
- 2017
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Ingår i: Residual Stresses 2016: ICRS-10, Materials Research Proceedings 2 (2016). - : Materials Research Forum LLC. ; , s. 73-78
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Konferensbidrag (refereegranskat)abstract
- 3D residual stresses in as manufactured EOS NickelAlloy HX, produced by laser powder bed additive manufacturing, are analysed on the surface closest to the build-plate. Due to the severe thermal gradient produced during the melting and solidification process, profound amounts of thermal strains are generated. Which can result in unwanted geometrical distortion and effect the mechanical properties of the manufactured component. Measurements were performed using a four-circle goniometer Seifert X-ray machine, equipped with a linear sensitive detector and a Cr-tube. Evaluation of the residual stresses was conducted using sin2ψ method of the Ni {220} diffraction peak, together with material removal technique to obtain in-depth profiles. An analysis of the material is reported. The analysis reveals unwanted residual stresses, and a complicated non-uniform grain structure containing large grains with multiple low angle grain boundaries together with nano-sized grains. Grains are to a large extent, not equiaxed, but rather elongated.
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| 2. |
- Sköldberg, Håkan, et al.
(författare)
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BIO-CCS I FJÄRRVÄRMESEKTORN – SYNTES
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den svenska fjärrvärmesektorn har stor potential att bidra med negativa koldioxidutsläpp genom bio-CCS, minst 10 Mton per år. Den största osäkerheten beträffande möjligheterna för bio-CCS gäller marknads förutsättningarna. Uppvärmningsbranschen har en vision om att år 2045 utgöra en kolsänka. Ett sätt att åstadkomma detta är genom att avskilja och lagra koldioxidutsläpp med biogent ursprung. Ett antal fjärrvärmeföretag har redan olika långt gångna planer på att satsa på bio-CCS. De har sett ett värde i att samarbeta kring hur detta kan åstadkommas. Ett led i detta är projektet Bio-CCS i fjärrvärmesektorn som består av ett gediget underlag baserat på forskning kring olika aspekter av frågan samt en strategi baserad på det underlaget. I denna rapport redovisas en syntes av detta forskningsarbete. Projektet visar att fjärrvärmesektorn har stor teoretisk potential att bidra med negativa koldioxidutsläpp, minst 10 Mton per år. I huvudsak är avskiljning, transport och lagring av koldioxid beprövad teknik även om tillämpningen i detta fall är ny. Även om bio-CCS är förknippad med energianvändning så bidrar tekniken sett ur ett systemperspektiv med stor nytta för att minska koldioxid[1]utsläppen. Bio-CCS är en relativt dyr teknik och det är angeläget att utnyttja samverkan och kluster för att exempelvis skapa ökad kostnadseffektivitet i transport och mellanlagring. Tillgång till lagringsplatser är en förutsättning för framgång och flera alternativ bedöms bli tillgängliga. Det kan dock uppstå konkurrens om tillgången till lagringsplatserna. De regelmässiga förutsättningarna för bio-CCS i Sverige har förbättrats avsevärt de senaste dryga decenniet. Flera regelmässiga hinder kvarstår dock. En del utgör mindre barriärer, andra är av mer betydande karaktär. Den största osäkerheten beträffande möjligheterna för bio-CCS gäller ekonomin. Flera potentiella finansieringsmetoder har studerats, både stöd, regleringar och frivilligmarknader. Det finns fortfarande oklarheter kring syftet med planerade stöd och det framtida ägandet av de negativa utsläppen. Det genomförda projektet har skapat ett forum för kunskapsuppbyggnad, erfarenhetsutbyte och nätverkande, vilket de deltagande företagen bedömt vara mycket värdefullt.
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| 3. |
- Johansson, Jonny, et al.
(författare)
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Project: EISCAT 3D
- 2007
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Annan publikation (populärvet., debatt m.m.)
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| 4. |
- Claesson, Lena, et al.
(författare)
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Expert Competence in Remote Diagnostics : Industrial Interests, Educational Goals, Flipped Classroom & Laboratory Settings
- 2018
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Ingår i: Online Engineering & Internet of Things. - Cham : Springer. - 9783319643526 - 9783319643519 ; , s. 438-451
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Konferensbidrag (refereegranskat)abstract
- The manufacturing industry are dependent of engineering expertise. Currently the ability to supply the industry with engineering graduates and staff that have an up-to- date and relevant competences might be considered as a challenge for the society. In this paper an education approach is presented where academia - industry - research institutes cooperate around the development and implementation of master level courses. The methods applied to reach the educational goals, concerning expert competence within remote diagnostics, have been on site and remote lectures given by engineering, medical and metrology experts. The pedagogical approach utilized has been flipped classroom. The main results show that academic courses developed in cooperation with industry requires flexibility, time and effort from the involved partners. The evaluation interviews indicate that student are satisfied with the courses and pedagogical approach but suggests more reconciliation meetings for course development. Labs early in the course was considered good, and division of labs at the system and the component level. However further long- term studies of evaluation of impact is necessary.
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| 5. |
- Gourdon, Mathias, 1980, et al.
(författare)
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Pulp mill biorefineries
- 2013
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Ingår i: International Process Integration Jubilee Conference, Gothenburg, Sweden, March 18-20 2013.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Grishenkov, Dmitry, 1983-, et al.
(författare)
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Ultrasound contrast agent loaded with nitric oxide as a theranostic microdevice : Theranostic contrast agent loaded with nitric oxide
- 2015
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Ingår i: Drug Design, Development and Therapy. - 1177-8881. ; 9, s. 2409-2419
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Tidskriftsartikel (refereegranskat)abstract
- The current study describes novel multifunctional polymer-shelled microbubbles (MBs) loaded with nitric oxide (NO) for integrated therapeutic and diagnostic applications, i.e. theranostics, of myocardial ischemia. We used gas filled MBs with an average diameter of 4 µm stabilized by a biocompatible shell of poly(vinyl)alcohol. In vitro acoustic tests showed a sufficient enhancement of the backscattered power (20 dB) acquired from the MBs suspension. The values of attenuation coefficient (0.8 dB/cm MHz) and phase velocities (1517 m/s) were comparable to those reported for the soft tissue. Moreover, polymer MBs demonstrate increased stability compared to clinically approved contrast agents with fracture threshold of about 900 kPa. In vitro chemiluminescence measurements demonstrated that dry powder of NO-loaded MBs releases its gas content in about 2 hours following an exponential decay profile with an exponential time constant equal 36 min. The application of high power ultrasound pulse (MI=1.2) on the MBs resuspended in saline decreases the exponential time constant from 55 to 4 min in air saturated solution and from 17 to 10 min in degased solution. Thus, ultrasound-triggered release of NO is achieved. Cytotoxicity tests indicate that phagocytosis of the MBs by macrophages starts within 6 to 8 hours. This is suitable time for initial diagnostics, treatment and monitoring of the therapeutic effect using single injection of the proposed multifunctional MBs.
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| 7. |
- Johansson, Gustav, et al.
(författare)
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Simulation of post-ADC digital beamforming for large aperture array radars
- 2010
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Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 45:RS3001
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents simulations and methods developed to investigate the feasibility of using a Fractional-Sample-Delay (FSD) system in the planned EISCAT_3D incoherent scatter radar. Key requirements include a frequency-independent beam direction over a 30 MHz band centered around 220 MHz, with correct reconstruction of pulse lengths down to 200 ns. The clock jitter from sample to sample must be extremely low for the integer sample delays. The FSD must also be able to delay the 30 MHz wide signal band by 1/1024th of a sample without introducing phase shifts, and it must operate entirely in baseband. An extensive simulation system based on mathematical models has been developed, with inclusion of performance-degrading aspects such as noise, timing error, and bandwidth. Finite Impulse Response (FIR) filters in the baseband of a band-pass-sampled signal have been used to apply true time delay beamforming. It has been confirmed that such use is both possible and well behaved. The target beam-pointing accuracy of 0.06° is achievable using optimized FIR filters with lengths of 36 taps and an 18 bit coefficient resolution. Even though the minimum fractional delay step necessary for beamforming is ∼13.1 ps, the maximum sampling timing error allowed in the array is found to be σ ≤ 120 ps if the errors are close to statistically independent.
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| 8. |
- Lundberg, Jan, et al.
(författare)
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Measurements of friction coefficients between rails lubricated with a friction modifier and the wheels of an IORE locomotive during real working conditions
- 2015
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 324-325, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- The real friction coefficients between the rails and the wheels on a 360. t and 10,800. kW IORE locomotive were measured using the locomotive׳s in-built traction force measurement system. The locomotive consisted of two pair-connected locomotives had a CoCo+CoCo bogie configuration, and hauled a fully loaded set of 68 ore wagons (120. t/wagon). The measurements were performed both on rails in a dry condition and on rails lubricated with a water-based top-of-rail (ToR) friction modifier on the Iron Ore Line between the cities of Kiruna and Narvik in Northern Sweden and Norway, respectively. Since full-scale measurements like these are costly, the friction coefficients were also measured at the same time and place using a conventional hand-operated tribometer, with and without the ToR friction modifier. The most important results are that the real friction coefficient is definitely not constant and is surprisingly low (0.10-0.25) when the ToR friction modifier is used, and that it is also significantly dependent on the amount of ToR friction modifier. A large amount will reduce the friction coefficient. Furthermore, it is concluded that the real friction coefficients are in general lower than the friction coefficients measured with the hand-operated tribometer. A final remark is thus that the use of a water-based ToR friction modifier can give excessively low friction, which can result in unacceptably long braking distances.
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| 9. |
- Saari, Juhamatti, 1985-, et al.
(författare)
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Using wavelet transform analysis and the support vector machine to detect angular misalignment of a rubber coupling
- 2015
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Ingår i: Maintenance, Condition Monitoring and DiagnosticsMaintenance Performance Measurement and Management. ; , s. 117-126
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Shaft misalignment is a common problem for many types of rotating systems. It can cause machine breakdowns due to the premature failure of bearings or other components. Common diagnostic approaches rely on detecting increasing vibration response spectra at multiples of the shaft speed. However, in many time-variant systems, such as wind turbines, the speed and load vary considerably, which can make spectrum analysis insufficient. In this paper, a method for detecting shaft misalignment by using wavelet analysis is proposed. The method was experimentally evaluated in a laboratory test rig for four different operating conditions by varying the rotational speed and load. An angular misalignment was introduced between a hydraulic pump (load) and a medium-sized industrial gearbox connected with a rubber coupling. Vibration data were collected by using two accelerometers mounted in an axial and a radial direction directly on the gearbox casing. The features extracted from wavelet representation were classified by using a support vector machine algorithm. The detection of misalignment and the sensitivity of the proposed method are presented using validation data and confusion matrices. The final results of the confusion matrices clearly indicate that this method can detect misalignment even when the speed and load vary. The proposed method can be used for systems which are connected with shafts and there are many similar systems (comprising an electric motor, a gearbox and a centrifugal pump) working under the same circumstances.
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| 10. |
- Stenström, Christer, et al.
(författare)
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Condition monitoring of cracks and wear in mining mills using water squirter ultrasonics
- 2015
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Ingår i: International Journal of Condition Monitoring. - : British Institute of Non-Destructive Testing (BINDT). - 2047-6426. ; 5:1, s. 2-8
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Tidskriftsartikel (refereegranskat)abstract
- Mining mills are continuously exposed to loads that give rise to wear of the liners, as well as fatigue and crack development in the steel shell. The feasibility of using water squirter ultrasonics for condition monitoring of the shell and the lining of mining mills during operation has been studied in this paper. This method will make it possible to monitor cracks in mining mills without stopping them, which can result in significant monetary savings due to less downtime and increased product quality. The practical requirements of such a system were first analysed, which shows that it is possible to achieve the spatial resolution of 1 × 1 mm, using a pulse-echo set-up with a pulse repetition frequency of approximately 6 kHz. Experiments were then performed on a lab-scale prototype, where typical defects were introduced. The results show that it is possible to detect and image internal defects down to a size of around 1 × 0.4 mm.
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