| 1. |
- Smith, Gudmund, et al.
(författare)
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Dialog hösten 2009
- 2010
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Ingår i: Kreativitet och mognad : festskrift tillägnad Professor Gudmund Smith på 90-årsdagen den 29 januari 2010. - 9789197871808 ; , s. 151-158
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Bokkapitel (refereegranskat)
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| 2. |
- Allgurén, Thomas, 1986, et al.
(författare)
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Investigation of the Behavior of Alkali Chlorides during Sulfur Recirculation in a Waste-to-Energy Facility
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- High temperature corrosion related issues are known problems for Waste-to-Energy facilities where the formation of alkali chlorides is among the most problematic species formed during the combustion. Sulfur Recirculation is a novel technology developed to reduce the chlorine content in the ash and in that way also the corrosivity of the ash. This concept has been installed at the Maabjerg Energy Center (MEC) in Denmark. This work aims to take a first step towards a reaction kinetics based model that can describe systems like the MEC boiler and to evaluate the impact of Sulfur Recirculation. This is done by implementing a plug flow reactor model in the software Chemkin. Previously obtained data from on-site experiments and CFD simulations is used as input to the model. The model is focused on describing the sulfation of alkali chlorides and the result from the model is compared to experiments. The model is able to predict the degree of sulfation with less than 10% deviation from the experimental results. Both the experiment and the model show a clear benefit from implementing sulfur recirculation which lowers the chlorine content in the up to as much as 70%. It is, however, also shown that the results are sensitive towards several of the assumptions made. Even though there is a relatively good agreement in final sulfation between model and experiments the model is not able to represent the detailed chemistry in a realistic way in its current state; further development is required.
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| 3. |
- Andersson, Christer M, et al.
(författare)
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A SiC Varactor With Large Effective Tuning Range for Microwave Power Applications
- 2011
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Ingår i: IEEE ELECTRON DEVICE LETTERS. - : IEEE Institute of Electrical and Electronics. - 0741-3106. ; 32:6, s. 788-790
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Tidskriftsartikel (refereegranskat)abstract
- SiC Schottky diode varactors have been fabricated for use in microwave power applications, specifically the dynamic load modulation of power amplifiers. A custom doping profile has been employed to spread the C(V) over a large bias voltage range, thereby increasing the effective tuning range under large voltage swing conditions. The small-signal tuning range is approximately six, and punch through is reached at a bias voltage of -60 V, while the breakdown voltage is on the order of -160 V. An interdigitated layout is utilized together with a self-aligned Schottky anode etch process to improve the Q-factor at 2 GHz, which is 20 at zero bias and approximately 160 at punch through.
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| 4. |
- Andersson, Mattias, et al.
(författare)
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A Filtering Delta Sigma ADC for LTE and Beyond
- 2014
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Ingår i: IEEE Journal of Solid-State Circuits. - 0018-9200. ; 49:7, s. 1535-1547
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThis paper presents a filtering ADC for the LTE communication standard, where a second-order Delta-Sigma modulator (DSM) is incorporated into the third-order Chebychev channel-select filter (CSF) of the radio receiver. The CSF introduces an additional third-order suppression of both thermal and quantization DSM noise, while the CSF transfer function is maintained. A design method for the filtering ADC accounting for unavoidable DSM-DAC delays is developed and experimentally demonstrated. The 65 nm CMOS prototype is clocked at 576/288 MHz with an 18.5/9.0 MHz LTE bandwidth, has an in-band gain of 26 dB, an SNDR of 56.4/58.1 dB, an input-referred noise of 5 nV/root Hz, and an out-of-band (half-duplex) IIP3 of 20/12 dBV(rms), with a power consumption of 7.9/5.4 mW and an overall state-of-the art performance.
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| 5. |
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| 6. |
- Dillner, Lena, et al.
(författare)
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Randomized healthservices study of human papillomavirus-based management of low-grade cytological abnormalities.
- 2011
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; okt, s. 151-159
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Tidskriftsartikel (refereegranskat)abstract
- Human Papillomavirus (HPV)-based management of women with borderline (ASCUS) or mildly abnormal (CINI) cervical cytology has been extensively studied in the research setting. We wished to assess safety and healthcare resource use of a real-life healthcare policy using HPV triaging.All 15 outpatient clinics involved in the organized population-based screening program in Stockholm, Sweden screening program were randomized to either continue with prior policy (colposcopy of all women with ASCUS/CINI) or to implement a policy with HPV triaging and colposcopy only of HPV-positive women. The trial enrolled the 3319 women that were diagnosed with ASCUS (n=1335) or CINI (n=1984) in Stockholm during 17(th) March 2003 to 16(th) January 2006. Detection of high-grade cervical lesions (CINII+) and health care cost consumption was studied by registry linkages.The proportion of histopathology-verified CINII+ was similar for the 2 policies (395/1752 women (22.5%; 95% Confidence interval (CI): 20,6-24,6%) had CINII+ diagnosed with HPV triaging policy, 318/1567 women (20.3%; 95%CI: 18,3-22,4%)) had CINII+ with colposcopy policy). 64% of women with ASCUS and 77% of women with CINI were HPV-positive. HPV-positivity was age-dependent, with 81% of women below 35 years of age and 44% of women above 45 years of age testing HPV-positive. HPV triaging was cost-effective only above 35 years of age.In conclusion, a real-life randomised healthservices study of HPV triaging of women with ASCUS/CINI demonstrated similar detection of CINII+ as colposcopy of all women.
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| 7. |
- Du, Chengjun, 1985, et al.
(författare)
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An analysis of image evaluation procedures for measurements of diesel spray characteristics
- 2014
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Ingår i: ILASS – Europe 2014, 26th Annual Conference on Liquid Atomization and Spray Systems, 8-10 Sep. 2014, Bremen, Germany.
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Konferensbidrag (refereegranskat)abstract
- In order to investigate the influence of the methods applied for measuring spray parameters such as liquid phase spray penetration and dispersion cone angle, Diesel spray experiments in a high pressure / high temperature chamber were performed under non-evaporating (30 ºC, 21.1 bar), evaporating (350 ºC, 43.4 bar) and combusting (600 ºC, 60 bar) conditions with a constant gas density 24.3 kg/m3. A high-speed video camera was used to record shadowgraph images. The images were analyzed both as individual images and as averages of 100 images at each time step. The influence of the threshold level to define the spray boundary on the measured spray penetration and dispersion cone angle was analyzed. Under non-evaporating and evaporating conditions, it was found that a change in threshold level has a larger influence on the values for the liquid spray penetration determined from the averaged images, compared to the values from the instantaneous images. The penetration lengths determined from the instantaneous and averaged images are generally quite similar. Under combusting conditions, during the early phase of the injection there are only small differences in the penetration length between the instantaneous and averaged images or when the threshold level is changed, which is in strong contrast to the later part where there is a high sensitivity to changes in the threshold level and there can be significant differences in lengths determined from instantaneous and averaged images. The spray dispersion angle was calculated along the whole spray based on the width at each distance from the nozzle tip. It was found that there is a region around 12 mm from the nozzle tip where the measured spray cone angle is constant during most of the injections. Further downstream the dispersion angle increases till about 75 % of the penetration length under non-evaporating and evaporating conditions, whereas it decreases under combusting conditions.
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| 8. |
- Du, Chengjun, 1985, et al.
(författare)
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Effect of Nozzle Geometry on Diesel Spray Characteristics under Non-Evaporating and Evaporating Conditions
- 2015
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Ingår i: ICLASS 2015 - 13th International Conference on Liquid Atomization and Spray Systems.
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Konferensbidrag (refereegranskat)abstract
- To investigate the effect of nozzle geometry on diesel spray characteristics, spray experiments were car-ried out in a spray chamber. Three different single-hole nozzles were used: (1) nozzle N1 - outlet diameter 140 µm with k-factor 0; (2) nozzle N2 - outlet diameter 140 µm with k-factor 2; (3) nozzle N3 - outlet diame-ter 136 µm with k-factor 2. Two constant gas densities of 15 kg/m3 and 30 kg/m3 were maintained under non-evaporating (ambient temperature 40 ºC) and evaporating (ambient temperature 400 ºC) conditions. The range of injection pressure was from 800 bar to 1600 bar. Liquid phase spray penetration and local spray cone angle along the spray profile were measured based on high speed shadowgraph images. In addition, spray momen-tum flux was measured. It was found that the effect of nozzle geometry on the liquid phase penetration and local spray cone angle were different for different gas density and injection pressure. Under non-evaporating conditions, as injection pressure was increased, nozzle N1 without conicity showed slightly slower liquid penetration and larger local cone angle than nozzles N2 and N3 at the density 15 kg/m3. As the gas density was increased to 30 kg/m3, the difference between the three nozzles was more evident. Under evaporating conditions, nozzle N3 with conicity showed shorter liquid phase penetration than nozzle N1. As the gas densi-ty is increased to 30 kg/m3, comparing the two nozzles (N1 and N2) which have the same outlet diameter but with different conicity, nozzle N2 with conicity showed longer liquid phase penetration than nozzle N1 with-out conicity.
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| 9. |
- Du, Chengjun, 1985, et al.
(författare)
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Effects of Nozzle Geometry on the Characteristics of an Evaporating Diesel Spray
- 2016
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Ingår i: SAE International Journal of Fuels and Lubricants. - : SAE International. - 1946-3952 .- 1946-3960. ; 9:3, s. 21-
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Tidskriftsartikel (refereegranskat)abstract
- The effects of nozzle geometry on diesel spray characteristics were studied in a spray chamber under evaporating conditions using three single-hole nozzles, one cylindrical and two convergent, designated N1 (outlet diameter 140 μm, k-factor 0), N2 (outlet diameter140 μm, k-factor 2) and N3 (outlet diameter 136 μm, k-factor 2). Spray experiments were performed with each nozzle at two constant gas densities (15 and 30 kg/m3) and an ambient temperature (673 K) at which evaporation occurs, with injection pressures ranging from 800 to 1600 bar. A light absorption and scattering method using visible and UV light was implemented, and shadow images of liquid and vapor phase fuel were recorded with high-speed video cameras. The cylindrical nozzle N1 yielded larger local vapor cone angles than the convergent nozzles N2 and N3 at both gas densities, and the difference became larger as the injection pressureincreased. The vapor phase penetration values for nozzle N1 and N3 were quite similar and always lower than those for N2. This is consistent with the impingement measurements, which showed that the momentum flux of nozzle N1 was only slightly greater than that of nozzle N3, while that of nozzle N2 was substantially greater. The vapor volume fractions measured along the spray’s center line were well explained by the one-dimensional transient diesel jet model, indicating that diesel spray vaporization is controlled by turbulent fuel-air mixing.
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| 10. |
- Du, Chengjun, 1985, et al.
(författare)
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Ignition delay, lift-off and soot luminescence in Diesel-ethanol spray combustion
- 2014
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Ingår i: 6th International Conference on Sustainable Automotive Technologies, 29-30 Sep. 2014, Gothenburg, Sweden..
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Konferensbidrag (refereegranskat)abstract
- To investigate the influence of ethanol blending in Diesel fuel on the spray combustion characteristics, experiments were carried out in an optically accessed high-pressure / high-temperature spray chamber. Three different fuels were investigated: (1) Diesel, based on the European EN590 standard; (2) E10 with 10% ethanol and (3) E20 with 20% ethanol. Gas conditions were kept at a constant gas density of 24.3 kg/m3 at a lower combusting temperature (550 ºC, 57.3 bar) and a higher combusting temperature (600 ºC, 60 bar). The experimental results showed that ignition delay and delay time of soot formation were increased as ethanol was blended in Diesel fuel. Less soot luminescence was observed and longer lift-off length was measured in Diesel-ethanol blends compared to pure Diesel.
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