| 1. |
- Fridriksson, Helgi, et al.
(författare)
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Effect of Piston Shape and Swirl Ratio on Engine Heat Transfer in a Light-Duty Diesel Engine
- 2014
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Konferensbidrag (refereegranskat)abstract
- Heat transfer losses are one of the largest loss contributions in a modern internal combustion engine. The aim of this study is to evaluate the contribution of the piston bowl type and swirl ratio to heat losses and performance. A commercial CFD tool is used to carry out simulations of four different piston bowl geometries, at three engine loads with two different swirl ratios at each load point. One of the geometries is used as a reference point, where CFD results are validated with engine test data. All other bowl geometries are scaled to the same compression ratio and make use of the same fuel injection, with a variation in the spray target between cases. The results show that the baseline case, which is of a conventional diesel bowl shape, provides the best emission performance, while a more open, tapered, lip-less combustion bowl is the most thermodynamically efficient. The results also show that the effects of swirl are not consequent throughout all piston geometries, as the flow field response to swirl variations is different in the various piston geometries.
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| 2. |
- Gustafsson, Ulf O., et al.
(författare)
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Adherence to the enhanced recovery after surgery protocol and outcomes after colorectal cancer surgery
- 2011
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Ingår i: Archives of surgery (Chicago. 1960). - : American Medical Association (AMA). - 0004-0010 .- 1538-3644. ; 146:5, s. 571-577
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To study the impact of different adherence levels to the enhanced recovery after surgery (ERAS) protocol and the effect of various ERAS elements on outcomes following major surgery. Design: Single-center prospective cohort study before and after reinforcement of an ERAS protocol. Comparisons were made both between and across periods using multivariate logistic regression. All clinical data (114 variables) were prospectively recorded. Setting: Ersta Hospital, Stockholm, Sweden. Patients: Nine hundred fifty-three consecutive patients with colorectal cancer: 464 patients treated in 2002 to 2004 and 489 in 2005 to 2007. Main Outcome Measures: The association between improved adherence to the ERAS protocol and the incidence of postoperative symptoms, complications, and length of stay following major colorectal cancer surgery was analyzed. Results: Following an overall increase in preoperative and perioperative adherence to the ERAS protocol from 43.3% in 2002 to 2004 to 70.6% in 2005 to 2007, both postoperative complications (odds ratio, 0.73; 95% confidence interval, 0.55-0.98) and symptoms (odds ratio, 0.53; 95% confidence interval, 0.40-0.70) declined significantly. Restriction of intravenous fluid and use of a preoperative carbohydrate drink were major independent predictors. Across periods, the proportion of adverse postoperative outcomes (30-day morbidity, symptoms, and readmissions) was significantly reduced with increasing adherence to the ERAS protocol (>70%, >80%, and >90%) compared with low ERAS adherence (<50%). Conclusion: Improved adherence to the standardized multimodal ERAS protocol is significantly associated with improved clinical outcomes following major colorectal cancer surgery, indicating a dose-response relationship.
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| 3. |
- Jönsson, Mattias, et al.
(författare)
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Technical evaluation of different motion-monitoring systems for respiratory gating in radiation therapy
- 2013
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Ingår i: Medical Physics in the Baltic States. - 1822-5721. ; , s. 38-41
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Konferensbidrag (refereegranskat)abstract
- The purpose of this work was to evaluate three motion-monitoring systems: Sentinel (TM), Catalyst (TM) (both C-RAD) and Real-time Position Management (RPM (TM)) system (Varian Medical Systems Inc) for respiratory gating in radiotherapy. To measure the systems. latency, an in-house built circuit with a microcontroller operating a piston was used. The trigger pulse was sent from the gating systems to the accelerator within 300 mu s. However, the response time of the accelerator could be over 300 ms
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