40 results on '"Andersson, Peter"'
Search Results
2. Geometrical optimisation of a segmented HPGe detector for spectroscopic gamma emission tomography—A simulation study
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Rathore, Vikram, Senis, Lorenzo, Andersson Sundén, Erik, Jansson, Peter, Håkansson, Ane, and Andersson, Peter
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- 2021
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3. Comparison of water phase diffusion experiments in laboratory and in situ conditions
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Voutilainen, Mikko, Kekäläinen, Pekka, Poteri, Antti, Siitari-Kauppi, Marja, Helariutta, Kerttuli, Andersson, Peter, Nilsson, Kersti, Byegård, Johan, Skålberg, Mats, Yli-Kaila, Maarit, and Koskinen, Lasse
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- 2019
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4. Determination of the rod-wise fission gas release fraction in a complete fuel assembly using non-destructive gamma emission tomography
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Holcombe, Scott, Andersson, Peter, Svärd, Staffan Jacobsson, and Hallstadius, Lars
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- 2016
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5. Cost Benefit Analysis of Dynamic Route Planning at Sea
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Andersson, Peter and Ivehammar, Pernilla
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- 2016
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6. Determination of wear volumes by chromatic confocal measurements during twin-disc tests with cast iron and steel
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Andersson, Peter and Hemming, Björn
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- 2015
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7. Ileorectal anastomosis in comparison with ileal pouch anal anastomosis in reconstructive surgery for ulcerative colitis — a single institution experience
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Andersson, Peter, Norblad, Rickard, Söderholm, Johan D., and Myrelid, Pär
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- 2014
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8. Friction reduction by texturing of DLC coatings sliding against steel under oil lubrication
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Koskinen, Jari, Tapper, Unto, Andersson, Peter, Varjus, Simo, Kolehmainen, Jukka, Tervakangas, Sanna, and Buss, Wolfgang
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- 2010
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9. Rapid bystander assessment of intrinsic fighting ability: behavioural and heart rate responses in rainbow trout
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Hojesjo, Johan, Andersson, Peter, Engman, Anders, and Johnsson, JoRgen I.
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Trout -- Analysis ,Zoology and wildlife conservation - Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.04.013 Byline: Johan Hojesjo, Peter Andersson, Anders Engman, Jorgen I. Johnsson Abstract: The ability of bystanders to assess the intrinsic fighting ability of potential opponents with and without contest information was examined in an experimental study using rainbow trout, Oncorhynchus mykiss. Behavioural and heart rate responses were monitored for bystanders observing size-matched conspecifics before and after a staged contest with an opponent. The results suggest that bystanders can rapidly and accurately assess the intrinsic fighting ability/quality of a potential opponent. Within 10 s, bystanders increased their visual exposure towards opponents subsequently becoming subordinate and decreased their exposure towards opponents becoming dominant. Male bystanders showed higher visual exposure towards opponents than did females, regardless of the sex of the opponent. This immediate behavioural response was subsequently (24h after the first exposure) followed by elevated heart rate in bystanders exposed to dominant opponents, probably reflecting a physiological stress response. Apparently, bystanders used reliable size-independent cues allowing a rapid behavioural response. The delayed physiological response probably arises from the chemical cues associated with the presence of a dominant opponent, or a combination of initial visual cues and subsequent continuous exposure to chemical cues. The results suggest that bystanders are able to rapidly assess the intrinsic fighting ability of a similar-sized potential opponent without information about its contest success against other individuals. This ability can be utilised by bystanders to withdraw from costly contest with low winning probability. Thus, escalated conflicts may be less common in nature than previously suggested by laboratory studies. Author Affiliation: Department of Zoology, Animal Ecology, Goteborg, Sweden Article History: Received 18 August 2006; Revised 20 October 2006; Accepted 5 April 2007 Article Note: (miscellaneous) MS. number: 9081R
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- 2007
10. Transfer of surface texture from silicon nitride rolls to stainless steel wire in cold-rolling
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Andersson, Peter, Wild, Michael, Levén, Jan, and Hemming, Björn
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- 2006
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11. Diodes based on blends of molecular switches and conjugated polymers
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Andersson, Peter, Robinson, Nathaniel D., and Berggren, Magnus
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- 2005
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12. In situ tracer tests to determine retention properties of a block scale fracture network in granitic rock at the Äspö Hard Rock Laboratory, Sweden
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Andersson, Peter, Byegård, Johan, Tullborg, Eva-Lena, Doe, Thomas, Hermanson, Jan, and Winberg, Anders
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- 2004
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13. Caution Warranted Regarding the Efficacy of iCBT in Patients With Symptomatic Paroxysmal Atrial Fibrillation.
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Andersson, Peter and Coyne, James
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ATRIAL fibrillation - Published
- 2023
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14. Characterization of a molten globule state of bovine carbonic anhydrase III: loss of asymmetrical environment of the aromatic residues has a profound effect on both the near- and far-UV CD spectrum
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Borén, Kristina, Andersson, Peter, Larsson, Marie, and Carlsson, Uno
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- 1999
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15. A Machine Learning Approach for Biomass Characterization.
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Ahmed, Mobyen Uddin, Andersson, Peter, Andersson, Tim, Aparicio, Elena Tomas, Baaz, Hampus, Barua, Shaibal, Bergström, Albert, Bengtsson, Daniel, Orisio, Daniele, Skvaril, Jan, and Zambrano, Jesús
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Abstract The aim of this work is to apply and evaluate different chemometric approaches employing several machine learning techniques in order to characterize the moisture content in biomass from data obtained by Near Infrared (NIR) spectroscopy. The approaches include three main parts : a) data pre-processing, b) wavelength selection and c) development of a regression model enabling moisture content measurement. Standard Normal Variate (SNV), Multiplicative Scatter Correction and Savitzky-Golay first (SG 1) and second (SG 2) derivatives and its combinations were applied for data pre-processing. Genetic algorithm (GA) and iterative PLS (iPLS) were used for wavelength selection. Artificial Neural Network (ANN), Gaussian Process Regression (GPR), Support Vector Regression (SVR) and traditional Partial Least Squares (PLS) regression, were employed as machine learning regression methods. Results shows that SNV combined with SG1 first derivative performs the best in data pre-processing. The GA is the most effective methods for variable selection and GPR achieved a high accuracy in regression modeling while having low demands on computation time. Overall, the machine learning techniques demonstrate a great potential to be used in future NIR spectroscopy applications. [ABSTRACT FROM AUTHOR]
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- 2019
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16. Accelerated epigenetic aging in suicide attempters.
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Jokinen, Jussi, Andersson, Peter, Chatzittofis, Andreas, Savard, Josephine, Rask-Andersen, Mathias, Åsberg, Marie, and Boström, Adrian Desai
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CELLULAR aging , *SUICIDE , *AGE , *ATTEMPTED suicide , *SUICIDE risk factors , *PHYSIOLOGICAL effects of acceleration - Abstract
Suicide attempts (SA) are associated with excess mortality of natural causes, putatively mediated in part by premature cellular senescence. Epigenetic age (EA) estimators of biological age have been previously demonstrated to strongly predict physiological dysregulation and mortality risk. Herein, we investigate if violent SA with high intent-to-die is predictive of epigenetics-derived estimates of biological aging. The genome-wide methylation pattern was measured using the Illumina Infinium Methylation EPIC BeadChip in whole blood of 88 suicide attempters. Subjects were stratified into two groups (low- [n = 58] and high-risk [n = 30]) based on SA method (violent or non-violent) and/or intent-to-die (high/low). Estimators of intrinsic and extrinsic EA acceleration, one marker optimized to predict physiological dysregulation (DNAmPhenoAge/AgeAccelPheno) and one marker optimized to predict lifespan (DNAmGrimAge/AgeAccelGrim) were investigated for associations to severity of SA, by univariate and multivariate analyses. The study was adequately powered to detect differences of 2.2 years in AgeAccelGrim in relation to SA severity. Baseline DNAmGrimAge exceeded chronological age by 7.3 years on average across all samples, conferring a mean of 24.6% increase in relation to actual age. EA acceleration markers did not differ between high-and low-risk suicide attempters. Thus, SA per se but not severity of SA is related to EA, implicating that excess non-suicidal mortality is unrelated to risk of suicide. Preventative healthcare efforts aimed at curtailing excess mortality after SA may benefit from acting equally powerful to recognize somatic comorbidities irrespective of the severity inherent in the act itself. [ABSTRACT FROM AUTHOR]
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- 2023
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17. Green approaches at sea – The benefits of adjusting speed instead of anchoring.
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Andersson, Peter and Ivehammar, Pernilla
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TRANSPORTATION , *FREIGHT & freightage , *ENERGY consumption , *SHIPBORNE automatic identification systems , *EMISSIONS (Air pollution) - Abstract
In this paper, the concept ‘green approaches’ already used in aviation is applied to cargo transportation at sea. Instead of anchoring outside a port waiting for berth, ships can adjust their speed to arrive just in time for berthing. With improved incentives for reducing speed and shared information about berthing times, green approaches instead of anchoring can be a way to reduce fuel consumption and emissions without increasing the transit times of goods. The present study estimates the benefits to society as a whole for the EU ports in the Baltic Sea with Automatic Identification System data applying a new method using data collected in real time. Data consists of all anchored ships awaiting berth on 40 different occasions in 2015 and are subsequently extrapolated to a year. Fuel consumption by the individual ships, emissions and values are calculated from the detailed data with established models and estimates of unit values. The potential benefits are estimated at 27 million euros per year in the scenario where the near 15,000 anchorings by ships annually awaiting berth may instead start a green approach 12 h prior to arrival and may reduce speed by 25%, using the middle unit values for fuel and emissions. The methodology used in the paper can be applied to estimate the benefits of green approaches in other areas with anchored vessels. [ABSTRACT FROM AUTHOR]
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- 2017
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18. Electrochromic display cells driven by an electrolyte-gated organic field-effect transistor
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Said, Elias, Andersson, Peter, Engquist, Isak, Crispin, Xavier, and Berggren, Magnus
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- 2009
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19. How should we proceed with disease-modifying treatments for multiple sclerosis?
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Andersson, Peter-Brian, Waubant, Emmanuelle, and Goodkin, Donald E.
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Multiple sclerosis -- Care and treatment ,Magnetic resonance imaging ,Drug therapy -- Evaluation - Published
- 1997
20. HPA-axis dysregulation is not associated with accelerated epigenetic aging in patients with hypersexual disorder.
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Boström, Adrian Desai E., Andersson, Peter, Chatzittofis, Andreas, Savard, Josephine, Rask-Andersen, Mathias, Öberg, Katarina G., Arver, Stefan, and Jokinen, Jussi
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HYPERSEXUALITY , *HYPOTHALAMIC-pituitary-adrenal axis , *SEX addiction , *CELLULAR aging , *AGE , *IMPULSE control disorders , *SOMATIC mutation , *METHYLATION - Abstract
Hypersexual disorder (HD) - a nonparaphilic sexual desire disorder with impulsivity component - was evaluated for inclusion as a diagnosis in the DSM-5 and the diagnosis compulsive sexual behavior disorder is included as an impulse control disorder in the ICD-11. Hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity is believed to affect cellular senescence and has been implicated in HD. No previous study investigated HD or HPA-axis dysregulation in relation to measures of epigenetic age (EA) acceleration. This study reports on a case-control study set-up from a well-characterized cohort, contrasting EA predictors in relation to 60 HD patients and 33 healthy volunteers (HV) and 19 mixed HD/HV exhibiting dexamethasone suppression test (DST) non-suppression to 73 mixed HD/HV DST controls. The genome-wide methylation pattern was measured in whole blood from 94 subjects using the Illumina Infinium Methylation EPIC BeadChip and preprocessed according to specialized protocols suitable for epigenetic age estimation. The online DNAm Age Calculator (https://dnamage.genetics.ucla.edu/) was implemented to retrieve various EA predictors, which were compared between the in-silico generated subgroups. Quality control analyses indicated strong correlations between the EA measure DNA methylation GrimAge (DNAm GrimAge – the EA clock most reliably associated with mortality risk) and chronological age in all sub-groups. The study was adequately powered to detect differences of 2.5 and 3.0 years in DNAm GrimAge minus age in relation to both HD and HPA-axis dysregulation, respectively. Baseline DNAm GrimAge exceeded chronological age by 2.8 years on average across all samples. No EA acceleration marker was associated with HD or DST suppression status (p > 0.05). EA acceleration markers shown to be strongly predictive of physiological dysregulation and mortality-risk, are not related to HD or DST non-suppression status (measured after 0.5 mg dexamethasone). The independency of HPA-axis dysregulation to EA acceleration does not support the biological relevance of this dosage-regimen when applied to patients with HD. These findings do not support the notion of accelerated cellular senescence in HD. Studies stratifying DST non-suppressors according to established dosage-regimens in somatic settings are needed to fully elucidate the putative contribution of HPA-axis dysregulation to EA. • EAA strongly predict physiological dysregulation and mortality risk. • Power to detect disparities between EA and age exceeding 2.5–3 years. • HD is not associated with any EAA predictor. • Suppression status post 0.5 mg Dexamethasone is independent of EAA. • Biological relevance of low-dose Dexamethasone regimens impugned. [ABSTRACT FROM AUTHOR]
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- 2022
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21. Global energy consumption due to friction in trucks and buses.
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Holmberg, Kenneth, Andersson, Peter, Nylund, Nils-Olof, Mäkelä, Kari, and Erdemir, Ali
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ENERGY consumption , *FRICTION , *VEHICLES , *COEFFICIENTS (Statistics) , *TRIBOLOGY , *DIESEL fuels - Abstract
Abstract: In this paper, we report the global fuel energy consumption in heavy-duty road vehicles due to friction in engines, transmissions, tires, auxiliary equipment, and brakes. Four categories of vehicle, representing an average of the global fleet of heavy vehicles, were studied: single-unit trucks, truck and trailer combinations, city buses, and coaches. Friction losses in tribocontacts were estimated by drawing upon the literature on prevailing contact mechanics and lubrication mechanisms. Coefficients of friction in the tribocontacts were estimated based on available information in the literature for four cases: (1) the average vehicle in use today, (2) a vehicle with today׳s best commercial tribological technology, (3) a vehicle with today׳s most advanced technology based upon recent research and development, and (4) a vehicle with the best futuristic technology forecasted in the next 12 years. The following conclusions were reached: [•] In heavy duty vehicles, 33% of the fuel energy is used to overcome friction in the engine, transmission, tires, auxiliary equipment, and brakes. The parasitic frictional losses, with braking friction excluded, are 26% of the fuel energy. In total, 34% of the fuel energy is used to move the vehicle. [•] Worldwide, 180,000 million liters of fuel was used in 2012 to overcome friction in heavy duty vehicles. This equals 6.5millionTJ/a; hence, reduction in frictional losses can provide significant benefits in fuel economy. A reduction in friction results in a 2.5 times improvement in fuel economy, as exhaust and cooling losses are reduced as well. [•] Globally a single-unit truck uses on average 1500l of diesel fuel per year to overcome friction losses; a truck and trailer combination, 12,500l; a city bus, 12,700l; and a coach, 7100l. [•] By taking advantage of new technology for friction reduction in heavy duty vehicles, friction losses could be reduced by 14% in the short term (4 to 8 years) and by 37% in the long term (8 to 12 years). In the short term, this would annually equal worldwide savings of 105,000 million euros, 75,000 million liters of diesel fuel, and a CO2 emission reduction of 200 million tones. In the long term, the annual benefit would be 280,000 million euros, 200,000 million liters of fuel, and a CO2 emission reduction of 530 million tonnes. [•] Hybridization and electrification are expected to penetrate only certain niches of the heavy-duty vehicle sector. In the case of city buses and delivery trucks, hybridization can cut fuel consumption by 25% to 30%, but there is little to gain in the case of coaches and long-haul trucks. Downsizing the internal combustion engine and using recuperative braking energy can also reduce friction losses. [•] Electrification is best suited for city buses and delivery trucks. The energy used to overcome friction in electric vehicles is estimated to be less than half of that of conventional diesel vehicles. Potential new remedies to reduce friction in heavy duty vehicles include the use of advanced low-friction coatings and surface texturing technology on sliding, rolling, and reciprocating engine and transmission components, new low-viscosity and low-shear lubricants and additives, and new tire designs that reduce rolling friction. [Copyright &y& Elsevier]
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- 2014
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22. Low-speed sliding tests with nodular cast iron in contact with steel wire and a diamond tip.
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Waudby, Richard, Andersson, Peter, and Holmberg, Kenneth
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NODULAR iron , *STEEL wire , *CERAMIC coating testing , *MECHANICAL wear , *MECHANICAL failures , *SURFACES (Technology) - Abstract
Abstract: Scratch testing has been well applied towards the adhesion and failure testing of thin, hard ceramic coatings upon numerous different types of substrate materials. It is common that the test sample is scratched with a contact tip that will not easily deform, such as a Rockwell C diamond tip. Such tips are often not relevant to real, industrial cases, in which the materials of the two counter surfaces are both subjected to some degree of wear. The present paper describes the use of a scratch tester with a newly developed steel wire sample geometry replacing the conventional diamond tip, and the results of the effect of increasing load, loading rate and lubrication may have upon an industrially relevant nodular cast iron versus steel wire contact scenario. [Copyright &y& Elsevier]
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- 2013
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23. Global energy consumption due to friction in passenger cars
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Holmberg, Kenneth, Andersson, Peter, and Erdemir, Ali
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ENERGY consumption , *AUTOMOBILES , *FRICTION , *BRAKE systems , *ELASTOHYDRODYNAMICS , *TRIBOLOGY , *ELECTRIC automobiles - Abstract
Abstract: This study presents calculations on the global fuel energy consumption used to overcome friction in passenger cars in terms of friction in the engine, transmission, tires, and brakes. Friction in tribocontacts was estimated according to prevailing contact mechanisms such as elastohydrodynamic, hydrodynamic, mixed, and boundary lubrication. Coefficients of friction in the tribocontacts were estimated based on available information in the literature on the average passenger car in use today, a car with today’s advanced commercial tribological technology, a car with today’s best advanced technology based upon recent research and development, and a car with the best technology forecasted in the next 10 years. The following conclusions were reached: [•] In passenger cars, one-third of the fuel energy is used to overcome friction in the engine, transmission, tires, and brakes. The direct frictional losses, with braking friction excluded, are 28% of the fuel energy. In total, 21.5% of the fuel energy is used to move the car. [•] Worldwide, 208,000 million liters of fuel (gasoline and diesel) was used in 2009 to overcome friction in passenger cars. This equals 360 million tonne oil equivalent per year (Mtoe/a) or 7.3millionTJ/a. Reductions in frictional losses will lead to a threefold improvement in fuel economy as it will reduce both the exhaust and cooling losses also at the same ratio. [•] Globally, one passenger car uses on average of 340l of fuel per year to overcome friction, which would cost 510 euros according to the average European gas price in 2011 and corresponds to an average driving distance of 13,000km/a. [•] By taking advantage of new technology for friction reduction in passenger cars, friction losses could be reduced by 18% in the short term (5–10 years) and by 61% in the long term (15–25 years). This would equal worldwide economic savings of 174,000 million euros and 576,000 million euros, respectively; fuel savings of 117,000 million and 385,000 million liters, respectively; and CO2 emission reduction of 290 million and 960 million tonnes, respectively. [•] The friction-related energy losses in an electric car are estimated to be only about half those of an internal combustion passenger car. Potential actions to reduce friction in passenger cars include the use of advanced coatings and surface texturing technology on engine and transmission components, new low-viscosity and low-shear lubricants and additives, and tire designs that reduce rolling friction. [Copyright &y& Elsevier]
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- 2012
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24. High-mobility group box protein 1 and its signalling receptors in human preterm and term cervix
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Dubicke, Aurelija, Andersson, Peter, Fransson, Emma, Andersson, Eva, Sioutas, Angelos, Malmström, Anders, Sverremark-Ekström, Eva, and Ekman-Ordeberg, Gunvor
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CELLULAR signal transduction , *MESSENGER RNA , *GENE expression , *PREMATURE labor , *CERVIX uteri , *PREGNANCY , *MEMBRANE proteins , *IMMUNOHISTOCHEMISTRY - Abstract
Abstract: The objective of this study was to identify possible changes in mRNA and protein expression of high-mobility group box protein 1 (HMGB1) and its suggested receptors – receptor for advanced glycation end-products (RAGE) and Toll-like receptor 2 (TLR2) and TLR4 – in human cervix during pregnancy, term and preterm labor. Cervical biopsies were taken from 58 women: 20 at preterm labor, 24 at term labor, 10 at term not in labor and 4 from non-pregnant women. Real-time RT-PCR was used to quantify mRNA expression, and immunohistochemistry and ELISA for protein analysis. HMGB1, RAGE, TLR2 and TLR4 proteins were localized and their mRNA expression was detected in the cervix. There was more extranuclear HMGB1 in the cervical epithelium and stroma in preterm and term labor compared to the term not in labor. TLR2 mRNA expression was upregulated 5-fold in term labor and 3-fold in preterm labor compared to term not in labor and non-pregnant controls. There was lower expression of TLR2 and TLR4 mRNAs in preterm labor compared to term. Lower mRNA expression of HMGB1 was found in the subgroup with preterm premature rupture of membranes than in the rest of the preterm group, where levels were significantly higher than in term labor. In conclusion, extranuclear expression of HMGB1 during labor suggests a possible role of HMGB1 during the process of cervical ripening. Changes in expression of mRNAs encoding HMGB1, TLR2 and TLR4 in preterm labor suggest differences in the mechanism of cervical ripening at preterm and term delivery. [Copyright &y& Elsevier]
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- 2010
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25. Hot rolling tests with steel bars and silicon nitride rolls
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Andersson, Peter, Levén, Jan, and Hemming, Björn
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STEEL bars , *SILICON nitride , *CERAMIC materials , *ROLLING (Metalwork) , *TITANIUM nitride - Abstract
Abstract: An experimental study was carried out to investigate the possibilities to use rolls made from Si3N4–TiN ceramic composite in hot rolling of steel. The results show that the wear of the ceramic material was lower than the wear of a reference cast iron. The results suggest that the Si3N4–TiN material is beneficial to use in a hot rolling process, on condition that the temperature of the work piece material is held sufficiently high. [Copyright &y& Elsevier]
- Published
- 2009
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26. Emotional adjustments to violent situations at secure units for adolescents: A staff perspective.
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Andersson, Peter
- Abstract
Secure units for adolescents are emotion-filled places. This paper examines how secure unit staff are socialized to match emotions to violent situations in a dynamic social context according to different feeling rules. The analysis applies theories about emotional culture as well as feeling rules. The article builds on 53 semi-structural interviews with staff at three secure units for detained boys and girls run by the Swedish National Board of Institutional Care. The findings illustrate different ways in which staff adjust their feelings in violent situations by both breaking and following rules. Results are discussed with respect to three themes: (1) emotional adjustments tuned to co-workers ; (2) emotional adjustments tuned to self ; and (3) emotional adjustments tuned to youth behaviour. The results show the importance of taking emotions seriously in daily work, as this makes it possible to visualize how staff emotionally socialize into their organization. Due to a lack of education and professional identity among staff, the socialization process is highly relevant, as it is primarily perceptions of youth and co-workers that control and develop feeling rules for staff. • Emotional adjustment is not an individual task, but a relational process where several emotional cultures exist together. • Staff are socialized in various ways: through co-workers and youths, but also through their own work experiences. • Staff often defer emotions and act in accordance with an emotional framework that does not take youth into account. [ABSTRACT FROM AUTHOR]
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- 2020
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27. Abstract ID: 16 Automated Monte Carlo QA system for volumetric modulated arc therapy: Possibilities and challenges.
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Chakarova, Roumiana, Krantz, Marcus, Cronholm, Rickard, Andersson, Peter, and Hallqvist, Andreas
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The objective of the work is to develop and implement an automated MC system for patient specific VMAT QA generating treatment planning system (TPS) compliant DICOM objects and including a stand-alone module for 3D analysis of dose deviations based on the normalized dose difference (NDD) method. The MC system developed is based on the EGSnrc code package with modifications [1] . The workflow consists of a number of modules connected to the TPS by means of DICOM exports and imports which are executed sequentially without user interaction. DVH comparison is performed in the TPS. In addition, MC- and TPS dose distributions are imported to the stand-alone analysis module based on the NDD formalism [2] . NDD failure maps and a pass rate for a certain threshold are obtained. 70 clinical plans are selected for analysis; 21 thorax plans, 26 prostate plans, 13 H&N plans and 10 gynecological plans. Agreement within 1.5% has been found between clinical- and MC data for the mean dose to the target volumes. The agreement is within 3% for parameters more sensitive to the shape of the DVH, e.g. D95% PTV or minimum dose to CTV. Tolerance criteria of 2%/3 mm are recommended for NDD analysis of prostate plans and 3%/3 mm for rest of the cases. Evaluation procedure is suggested where NDD analysis is the first step. For pass rate lower than 95% the evaluation continues with comparison of DVH parameters. For deviations larger than 2%, a visual inspection of the clinical- and MC dose distributions is performed. A fully automated evaluation is hindered by artefacts in the CT images, presence of contrast in the bladder, dose to air included in the target volume, interpretation of HU in rectum etc. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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28. [P233] Investigation of the response of cylindrical ionization chamber in non-reference conditions when using high-energy photon beams.
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Andersson, Peter, Swanpalmer, John, and Chakarova, Roumiana
- Abstract
Purpose To investigate the response of CC13 cylindrical ionization chamber in non-reference conditions with focus on the penumbra region and the depth of maximum dose when using high-energy photon beams. This chamber is used for beam data measurements and also for pre-treatment quality assurance procedures for dynamic treatments. Methods Measurements and Monte Carlo calculations are performed, employing a Varian iX Linac (6 MV photon beam), at the depths of 15 mm and 100 mm for the field sizes of 20 × 20 mm 2 ; 20×100 mm 2 and 100×100 mm 2 . The Monte Carlo model is developed using the egs-chamber in the EGSnrc package. Conversion factors are calculated relating the absorbed dose to air in the air cavity of the chamber to the absorbed dose to water through using: (a) water volume equal to the air cavity of the chamber, (b) 1×1×1 mm 3 water voxel representing point dose. Corresponding correction factors, C w/chamber and C w,point/chamber , are determined to quantify the variations in the conversion factors. Results Agreement within 3.5%/0.5 mm is obtained between the measurements and calculations. The correction factors for a chamber position at the central axis of the beam and at the center of the field penumbra are between 0.98 and 1.02 for all field sizes and depths examined. The largest corrections are seen for off-axis positions 3 mm beyond the penumbra center where C w,point/chamber varies between 0.54 and 0.71 for the depth of 100 mm and 0.45 and 0.58 for the depth of 15 mm indicating an overestimation of the absorbed dose to water when using the CC13 chamber. C w,point/chamber factors up to 1.27 are obtained in regions close to the penumbra inside the 20×20 mm 2 and 20×100 mm 2 fields indicating an underestimation of the absorbed dose to water. The maximum variation of the C w/chamber factors is between 0.70 and 1.06 for the 20×20 mm 2 field at the depth of 15 mm. Conclusions Uncorrected chamber response of the CC13 chamber, or similar, results in under or overestimation of the absorbed dose to water at positions inside or outside of the beam close to the penumbra for small as well as large field sizes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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29. Risk of Rectal Cancer After Colectomy for Patients With Ulcerative Colitis: A National Cohort Study.
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Abdalla, Maie, Landerholm, Kalle, Andersson, Peter, Andersson, Roland E., and Myrelid, Pär
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Background & Aims Patients with ulcerative colitis (UC) have an increased risk of rectal cancer, therefore reconstruction with an ileal pouch–anal anastomosis (IPAA) generally is preferred to an ileorectal anastomosis (IRA) after subtotal colectomy. Similarly, completion proctectomy is recommended for patients with ileostomy and a diverted rectum, although this approach has been questioned because anti-inflammatory agents might reduce cancer risk. We performed a national cohort study in Sweden to assess the risk of rectal cancer in patients with UC who have an IRA, IPAA, or diverted rectum after subtotal colectomy. Methods We collected data from the Swedish National Patient Register for a cohort of 5886 patients with UC who underwent subtotal colectomy with an IRA, IPAA, or diverted rectum from 1964 through 2010. Patients who developed rectal cancer were identified from the Swedish National Cancer Register. The risk of rectal cancer was compared between this cohort and the general population by standardized incidence ratio analysis. Results Rectal cancer occurred in 20 of 1112 patients (1.8%) who received IRA, 1 of 1796 patients (0.06%) who received an IPAA, and 25 of 4358 patients (0.6%) with a diverted rectum. Standardized incidence ratios for rectal cancer were 8.7 in patients with an IRA, 0.4 in patients with an IPAA, and 3.8 in patients with a diverted rectum. Risk factors for rectal cancer were primary sclerosing cholangitis in patients with an IRA (hazard ratio, 6.12), and colonic severe dysplasia or cancer before subtotal colectomy in patients with a diverted rectum (hazard ratio, 3.67). Conclusions In an analysis of the Swedish National Patient Register, we found that the risk for rectal cancer after colectomy in patients with UC is low, in relative and absolute terms, after reconstruction with an IPAA. An IRA and diverted rectum are associated with an increased risk of rectal cancer, compared with the general population, but the absolute risk is low. Patients and their health care providers should consider these findings in making decisions to leave the rectum intact, perform completion proctectomy, or reconstruct the colon with an IRA or IPAA. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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30. Applying image analysis techniques to tomographic images of irradiated nuclear fuel assemblies.
- Author
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Davour, Anna, Jacobsson Svärd, Staffan, Andersson, Peter, Grape, Sophie, Holcombe, Scott, Jansson, Peter, and Troeng, Mats
- Subjects
- *
IMAGE analysis , *TOMOGRAPHY , *NUCLEAR fuels , *DATA mining , *CROSS-sectional method , *PROTON-induced gamma ray emission , *TEMPLATE matching (Digital image processing) , *NUCLEAR fuel rods - Abstract
In this paper we present a set of image analysis techniques used for extraction of information from cross-sectional images of nuclear fuel assemblies, achieved from gamma emission tomography measurements. These techniques are based on template matching, an established method for identifying objects with known properties in images. We demonstrate a rod template matching algorithm for identification and counting of the fuel rods present in the image. This technique may be applicable in nuclear safeguards inspections, because of the potential of verifying the presence of all fuel rods, or potentially discovering any that are missing. We also demonstrate the accurate determination of the position of a fuel assembly, or parts of the assembly, within the imaged area. Accurate knowledge of the assembly position enables detailed modelling of the gamma transport through the fuel, which in turn is needed to make tomographic reconstructions quantifying the activity in each fuel rod with high precision. Using the full gamma energy spectrum, details about the location of different gamma-emitting isotopes within the fuel assembly can be extracted. We also demonstrate the capability to determine the position of supporting parts of the nuclear fuel assembly through their attenuating effect on the gamma rays emitted from the fuel. Altogether this enhances the capabilities of non-destructive nuclear fuel characterization. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
31. Treating model inadequacy in fuel performance model calibration by parameter uncertainty inflation.
- Author
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Robertson, Gustav, Sjöstrand, Henrik, Andersson, Peter, Hansson, Joachim, and Blair, Paul
- Subjects
- *
NUCLEAR fuel claddings , *HYDROGEN oxidation , *CALIBRATION , *MARKOV chain Monte Carlo , *NUCLEAR industry - Abstract
The nuclear industry uses fuel performance codes to demonstrate integrity preservation of fuel rods. These codes include a complex system of models with empirical constants that one needs to calibrate for best estimates and uncertainties. However, deriving the appropriate level of uncertainty is often challenging due to model inadequacies. This paper presents a method to address model inadequacies by adapting the mean and covariance of the model parameters so that the propagated uncertainty conforms with the spread of the residuals rather than calibrating the model parameters directly. We demonstrate the method on synthetic data sets from an artificial test-bed containing a cladding oxidation and a hydrogen pick-up model. A repeated validation using many synthetic data sets shows that the method is robust and handles model inadequacies appropriately in most cases. Furthermore, we compare with traditional calibration and show model inadequacy leads to underestimation of uncertainties if not addressed. • A simplified model for hydrogen pick-up and oxidation is implemented. • Synthetic data with the desired level of model inadequacy is generated. • Model inadequacy harms calibration, leading to underestimated uncertainties. • An inflated uncertainty of model parameters can account for model inadequacy. • Repeated calibration shows a promising method for treating model inadequacies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
32. A phytobezoar in the acute abdomen
- Author
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Kvitting, John-Peder Escobar, Andersson, Peter, and Druvefors, Pelle
- Subjects
- *
BEZOARS , *ACUTE abdomen , *ABDOMINAL pain , *TOMOGRAPHY , *ULTRASONIC imaging , *ABDOMINAL surgery , *DIFFERENTIAL diagnosis , *DISEASES in older women , *PATIENTS - Abstract
Abstract: A phytobezoar is a rare differential diagnosis in the acute abdomen. An 89-year-old woman presented with lower abdominal pain. A computed tomography scan and ultrasound suggested the presence of a bezoar. A phytobezoar was extracted surgically, and a resection was performed of the perforated small bowel segment. The etiology and management of phytobezoars are discussed. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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33. Wear characteristics of water-lubricated SiC journal bearings in intermittent motion
- Author
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Andersson, Peter, Nikkila, Antti-Pekka, and Lintula, Pekka
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- 1994
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34. Tribology in the Nordic Countries
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Holmberg, Kenneth and Andersson, Peter
- Published
- 1994
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35. Efficacy of topical honey compared to systemic gentamicin for treatment of infected war wounds in a porcine model: A non-inferiority experimental pilot study.
- Author
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Muhrbeck, Måns, Wladis, Andreas, Lampi, Maria, Andersson, Peter, and Junker, Johan P.E.
- Subjects
- *
WAR wounds , *GENTAMICIN , *BACTERIAL colonies , *HONEY , *AREA measurement , *PILOT projects , *WOUND healing , *WOUND infections , *ANIMAL experimentation , *SWINE , *STAPHYLOCOCCUS aureus , *ANTIBIOTICS - Abstract
Background: In armed conflicts, infected wounds constitute a large portion of the surgical workload. Treatment consists of debridements, change of dressings, and antibiotics. Many surgeons advocate for the use of honey as an adjunct with the rationale that honey has bactericidal and hyperosmotic properties. However, according to a Cochrane review from 2015 there is insufficient data to draw any conclusions regarding the efficacy of honey in treatment of wounds. We, therefore, decided to evaluate if honey is non-inferior to gentamicin in the treatment of infected wounds in a highly translatable porcine wound model.Material and Methods: 50 standardized wounds on two pigs were infected with S. aureus and separately treated with either topically applied Manuka honey or intramuscular gentamicin for eight days. Treatment efficacy was evaluated with quantitative cultures, wound area measurements, histological, immunohistochemical assays, and inflammatory response.Results: Topically applied Manuka honey did not reduce bacterial count or wound area for the duration of treatment. Intramuscular gentamicin initially reduced bacterial count (geometric mean 5.59*¸0.37 - 4.27*¸0.80 log10 (GSD) CFU/g), but this was not sustained for the duration of the treatment. However, wound area was significantly reduced with intramuscular gentamicin at the end of treatment (mean 112.8 ± 30.0-67.7 ± 13.2 (SD) mm2). ANOVA-analysis demonstrated no variation in bacterial count for the two treatments but significant variation in wound area (p<0.0001). The inflammatory response was more persistent in the pig with wounds treated with topically applied Manuka honey than in the pig treated with intramuscular gentamicin.Conclusion: At the end of treatment S. aureus count was the same with topically applied Manuka honey and intramuscular gentamicin. The wound area was unchanged with topically applied Manuka honey and decreased with intramuscular gentamicin. Topically applied Manuka honey could consequently be non-inferior to intramuscular gentamicin in reducing S. aureus colonization on the wound's surface, but not in reducing wound size. The use of Manuka honey dressings to prevent further progression of a wound infection may therefore be of value in armed conflicts, where definite care is not immediately available. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
36. Thickness dependent variations in surface phosphor thermometry during transient combustion in an HCCI engine.
- Author
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Knappe, Christoph, Algotsson, Martin, Andersson, Peter, Richter, Mattias, Tunér, Martin, Johansson, Bengt, and Aldén, Marcus
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- *
SURFACE chemistry , *PHOSPHORS , *THICKNESS measurement , *COMBUSTION , *DIESEL motors , *THERMOMETRY , *HEAT transfer , *THERMAL properties - Abstract
Abstract: Phosphor thermometry is a semi-invasive measurement technique which is commonly used for temperature determination in combustion applications. Surface temperature measurements using thermographic phosphors rely on the assumption that the phosphor layer is thin enough in order to adopt the surface temperature non-intrusively. This work compares the temperature information, recorded from two opposing sides of phosphor films, coated on a translucent part of the combustion chamber wall inside a car engine. The film thickness was varied between 5 and 72μm and two different phosphors were studied; CdWO4 and La2O2S:Eu. For both phosphors, the results showed no significant differences. Being subject to unsteady heat transfer during fired engine operation, phosphor coatings above 20μm in thickness experienced a significant temperature gradient between the front- and the backside of the coating, whereas thinner layers did not seem to be affected within the limits of measurement accuracy and precision. Cycle-to-cycle variations of the global gas temperature were not found to correlate with phosphor temperature variations. However, a strong temperature correlation between opposite sides of the phosphor coating was observed for film thicknesses below 20μm during engine cycle-to-cycle variations. [Copyright &y& Elsevier]
- Published
- 2013
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- View/download PDF
37. Influence of load on the tribological conditions in piston ring and cylinder liner contacts in a medium-speed diesel engine
- Author
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Tamminen, Jaana, Sandström, Carl-Erik, and Andersson, Peter
- Subjects
- *
SIMULATION methods & models , *COMPUTER software industry , *INTEGRATED software , *COMPUTER simulation - Abstract
Abstract: The present work is an attempt to determine the oil film thickness in a medium-speed four-stroke diesel engine with a cylinder diameter of 200mm. Experimental research on this topic was found necessary due to the limited amount of published information available with reference to engines of the present size. The experimental part of the study was carried out as firing engine tests, with an instrumented piston, equipped with telemetric data transmission, and an instrumented cylinder liner in a 6-in-line test engine. The study was carried out for different parts of the four-stroke working cycle and for different levels of engine power output. The results were compared with the results of computer simulations, carried out using a commercial software package. The conclusions of the study comprise aspects on the formation and development of the oil film between the rings and the liner under a set of load levels together with the periodical fluctuation during different strokes of the working cycle. [Copyright &y& Elsevier]
- Published
- 2006
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38. Flow structure and phase distribution in stratified and slug flows measured by X-ray tomography.
- Author
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Hu, Bin, Langsholt, Morten, Liu, Lan, Andersson, Peter, and Lawrence, Chris
- Subjects
- *
STRATIFIED flow , *X-ray computed microtomography , *MULTIPHASE flow , *GAS phase reactions , *GAS-liquid interfaces , *HIGH pressure (Technology) , *PIPELINES - Abstract
Flow structures and phase distributions in two- and three-phase stratified and slug flows were studied with a fast-response X-ray tomography system. A large number of experiments were carried out in a 25 m long near-horizontal pipeline with an internal diameter of 100 mm. A dense gas, SF 6 , was used to simulate the gas phase in high-pressure gas-condensate pipelines. Detailed measurements of the flow were made with the X-ray system at various superficial velocities, two different pressures (4 and 7.2 bara, giving gas densities of 24 and 42 kg/m 3 , respectively), and three different inclination angles: 0, +1 and +5 degrees. Both qualitative observations and quantitative measurements were obtained which illustrate the different types of interface structure and fluid flow behaviour. The detailed measurements have also been used to obtain a more reliable correlation for predicting the fraction of gas bubbles entrained in the liquid layer in turbulent stratified gas–liquid flows. The measurements in three-phase slug flows reveal interesting phenomena regarding the interactions of the oil–water and gas–oil interfaces. Depending on the flow conditions, the oil–water interface can sometimes decouple from the gas–liquid interface, leading to oil-dominated slugs flowing on top of a water layer of nearly constant thickness. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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39. Global energy consumption due to friction in paper machines
- Author
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Holmberg, Kenneth, Siilasto, Roope, Laitinen, Tarja, Andersson, Peter, and Jäsberg, Ari
- Subjects
- *
PAPERMAKING machinery , *ENERGY consumption , *FRICTION , *MIXING machinery , *ELECTRICAL energy , *PAPER mills , *ELASTOHYDRODYNAMICS - Abstract
Abstract: Calculations on the global energy consumption used to overcome friction in paper machines in terms of friction in motors, transmissions, pumps, blowers, agitators, pipes and the roll systems are presented. The following was concluded: [–] The energy consumed to overcome friction in a paper mill is in the range 15–25%. [–] Globally there were 8525 paper and paperboard machines in operation in 2012. One paper machine uses on an average 140TJ of electrical energy per year. Of this 32% is consumed to overcome friction, 36% is used for the paper production and mass transportation and 32% is other losses. [–] The friction losses in an average paper machine are in total 44.8TJ per year, and they are distributed as 32% due to friction in water-lubricated sliding in seals, doctor blades and fabric/support contacts, 23% due to friction in elastohydrodynamic rolling contacts, 22% due to friction in elastohydrodynamic rolling–sliding contacts, 15% due to friction in oil-lubricated seals and 8% due to friction in hydrodynamically lubricated contacts. [–] Worldwide 105,000GWh electrical power was used in 2009 to overcome friction in paper machines. This equals to 381,000TJ of annual energy consumption. [–] By taking advantage of new technology for friction reduction in paper machines, friction losses could be reduced by 11% in the short term (about 10 years), and by 23.6% in the long term (20–25 years). This would equal to annual worldwide economic savings of 2000 million euros and 4200 million euros; electricity savings of 36,000 and 78,000GWh; and CO2 emission reduction of 10.6 million and 22.7 million tonnes. Potential mechanisms to reduce friction in paper machines include the use of low-friction and highly durable coatings, surface engineering including texturing, low-viscosity and low-shear lubricants and fluids, novel additives, new materials in seals, doctorblades and fabrics, as well as new designs. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
40. The degradation of gamma-ray mass attenuation of UOX and MOX fuel with nuclear burnup.
- Author
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Atak, Haluk, Anastasiadis, Anastasios, Jansson, Peter, Elter, Zsolt, Sundén, Erik Andersson, Holcombe, Scott, and Andersson, Peter
- Subjects
- *
MIXED oxide fuels (Nuclear engineering) , *GAMMA ray spectrometry , *MASS attenuation coefficients , *NUCLEAR fuels , *NUCLEAR reactor cores , *ATTENUATION coefficients - Abstract
Nondestructive gamma-ray spectrometry of nuclear fuel is routinely performed in axial gamma scanning devices and more recently with gamma emission tomography. Following the irradiation of a fresh nuclear fuel with high intensity neutron flux in a nuclear reactor core, a great number of gamma-emitting radionuclides are created. These can be utilized for gamma spectrometric techniques. However, due to the high density and atomic number of the nuclear fuel, self-attenuation of gamma-rays is a challenge, which requires attenuation correction in order to perform accurate analysis of the source activity in the fuel. In this study, the degradation of the gamma-ray mass attenuation with burnup was investigated and, in addition, a predictive model was created by investigating the attenuation change at various gamma energies caused by the burnup of the nuclear fuel. This model is intended for use by spectrometry practitioners inspecting nuclear fuel. To this aim, the energy-dependent gamma-ray mass-attenuation coefficients were investigated as a function of burnup for UOX, and three MOX fuels having different initial Pu contents. The Serpent 2 reactor physics code was used to simulate the burnup history of the fuel pins. The nuclide inventory of the Serpent 2 output is combined with the NIST XCOM database to calculate the mass attenuation coefficients. The mass attenuation coefficient of the fuel was found to decrease with the fuel burnup, in the range of a few percent, depending on the burnup and gamma energy. Also, a theoretical burnup dependent swelling model was imposed on fuel density to see how linear attenuation coefficient of fuel material is changed. Furthermore, greater effect may be expected on the transmitted intensity, where a simulation study of a PWR assembly revealed that the contribution from the inner rods in a scanned fuel assembly increased by tens of percent compared to the one with non-irradiated fresh fuels, when shielded by the outer rods of the assembly. A sensitivity analysis was performed in order to test the effect of a number of geometrical and operational reactor parameters that were considered to potentially effect the mass attenuation coefficient. Finally, a simple-to-use predictive model was constructed providing the mass-attenuation coefficient [cm2/g] of fuel as a function of burnup [MWd/kg HM and initial Pu content [wt%]. The resulting predictive model was optimized by using the nonlinear regression method. • Gamma emission tomography enables nondestructive characterization of nuclear fuel. • Self-attenuation of gamma-rays in nuclear fuel with high burnup was investigated. • A predictive model was constructed as a function of burnup and initial Pu content. • Model is proposed for use by spectrometry practitioners inspecting nuclear fuel. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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