Methodology for Phase Doppler Anemometry Measurements on a Multi-Hole Diesel Injector

[EN] In this paper, a methodology for Phase Doppler Anemometry (PDPA) measurements on a multi-hole diesel injector is developed. Several key considerations were taken into account in this methodology: The windows for PDPA optical access must be clean, since fuel impregnated in these could preclude the droplets velocity acquisition. Some parts, including a device for spray isolation, were designed and manufactured to fulfill this goal. Taking into account that only one spray is measured, the isolation device captures all except three of the sprays (including the spray of interest). The two plumes accompanying the main spray were thought to conserve the actual air entrainment and thus the spray behavior. The spray of interest was aligned horizontally to ease the way that the PDPA measurements are carried out. The plume was lined up by means of the MIE-Scattering macroscopic optical technique. Images were acquired for several injection events and spray contours were detected and processed with a purpose-built Matlab tool. At each time step a spray axis inclination was estimated using the centroids from instantaneous contours. Also, preliminary droplet velocity measurements were made to check the effectiveness of the alignment and spray isolation strategies. Both geometrical characterization and spray alignment had very low measurement error. Radial velocity profiles show that PDPA measurements with this set-up configuration preserved the spray behavior.This research was performed in the frame of the project "Estudio de la interaccion chorro-pared en condiciones realistas de motor" reference TRA2015-67679-c2-1-R from Ministerio de Economia y Competitividad (Spanish Ministry of Economy). The equipment used in this work has been partially supported by FEDER Project funds "Dotacion de infraestructuras cientifico tectinas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", framed in the operation program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. Jhoan S. Giraldo was supported by a research grant from Generalitat Valenciana (Programa Santiago Grisolia, GRISOLIA/2013/007).Payri, R.; Gimeno, J.; Marti-Aldaravi, P.; Giraldo-Valderrama, JS. (2017). Methodology for Phase Doppler Anemometry Measurements on a Multi-Hole Diesel Injector. Experimental Techniques. 41(2):95-102. https://doi.org/10.1007/s40799-016-0154-1S95102412Lee J, Kang S, Rho B (2002) Intermittent atomization characteristics of multi-hole and single-hole diesel nozzle. KSME Int J 16(12):1693–1701Lee BH, Song JH, Chang YJ, Jeon CH (2010) Effect of the number of fuel injector holes on characteristics of combustion and emissions in a diesel engine. Int J Automot Technol 11(6):783– 791Lee J, Kaug S, Rho B (2003) Atomization characteristics of intermittent multi-hole diesel spray using time-resolved pdpa data. KSME Int J 17(5):766–775Zhou L-Y, Dong S-F, Cui H-F, Wu X-W, Xue F-Y, Luo F-Q (2016) Measurements and analyses on the transient discharge coefficient of each nozzle hole of multi-hole diesel injector. Sensors Actuators A Phys 244:198–205Payri R, Salvador FJ, Manin J, Viera A (2016) Diesel ignition delay and lift-off length through different methodologies using a multi-hole injector. Appl Energy 162:541–550Payri R, García-Oliver JM, Bardi M, Manin J (2012) Fuel temperature influence on diesel sprays in inert and reacting conditions. Appl Therm Eng 35:185–195Payri F, Payri R, Bardi M, Carreres M (2014) Engine combustion network: Influence of the gas properties on the spray penetration and spreading angle. Exp Thermal Fluid Sci 53:236– 243Payri R, Gimeno J, Bardi M, Plazas AH (2013) Study liquid length penetration results obtained with a direct acting piezo electric injector. Appl Energy 106(0):152–162Soare V (2007) Phase Doppler Measurements in Diesel Dense Sprays: Optimisation of Measurements and Study of the Orifice Geometry Influence over the Spray at Microscopic Level. PhD thesis, Universitat Politècnica de ValenciaAraneo L, Tropea C (2000) Improving phase doppler measurements in a diesel spray. SAE paperCoghe A, Cossali GE (2012) Quantitative optical techniques for dense sprays investigation: A survey. Optics and Lasers in Engineering 50(1):46–56. Advances in Flow VisualizationPayri R, Araneo L, Shakal J, Soare V (2008) Phase doppler measurements: system set-up optimization for characterization of a diesel nozzle. J Mech Sci Technol 22(8):1620–1632Desantes JM, Payri R, Salvador FJ, Soare V (2005) Phase doppler measurements: system set-up optimization for characterization of a diesel nozzle. In: SAE Technical Paper. SAE International, 04Bracco FV, Reitz RD (1979) On the dependence of spray angle and other spray parameters on nozzle design and operating conditions. SAE Technical PaperGavaises M, Andriotis A (2006) Cavitation inside multi-hole injectors for large diesel engines and its effect on the near-nozzle spray structure. In: SAE Technical Paper. SAE International, 04Macian V, Payri R, Garcia A, Bardi M (2012) Experimental evaluation of the best approach for diesel spray images segmentation. Exp Tech 36(6):26–34Payri R, Gimeno J, Viera JP, Plazas AH (2013) Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector. Fuel 113:257– 265Koo Ja-Ye Hung C, Martin JK (1997) Injection pressure effects upon droplet behaviour in transient diesel sprays. SAE PaperLee J, Kang S, Rho B (2003) Time-resolved analysis of turbulent mixing flow characteristics of intermittent multi-hole diesel spray using 2-d pdpa. JSME International Journal Series B Fluids and Thermal Engineering 46 (3):425–433Sinnamon J, Lancaster D, Stiener J (1980) An experimental and analytical study of engine fuel spray trajectories. SAE Technical PaperDesantes JM, Salvador FJ, López JJ, De la Morena J (2011) Study of mass and momentum transfer in diesel sprays based on x-ray mass distribution measurements and on a theoretical derivation. Exp Fluids 50 (2):233–246Hinze (1975) Turbulence. McGraw-Hill, New YorkSchlichting H (1979) Boundary Layer Theory. McGraw-Hill, New YorkDesantes JM, Payri R, Salvador FJ, Gil A (2006) Development and validation of a theoretical model for diesel spray penetration. Fuel 85:910–91

The updating of clinical practice guidelines: insights from an international survey

BACKGROUND: Clinical practice guidelines (CPGs) have become increasingly popular, and the methodology to develop guidelines has evolved enormously. However, little attention has been given to the updating process, in contrast to the appraisal of the available literature. We conducted an international survey to identify current practices in CPG updating and explored the need to standardize and improve the methods. METHODS: We developed a questionnaire (28 items) based on a review of the existing literature about guideline updating and expert comments. We carried out the survey between March and July 2009, and it was sent by email to 106 institutions: 69 members of the Guidelines International Network who declared that they developed CPGs; 30 institutions included in the U.S. National Guideline Clearinghouse database that published more than 20 CPGs; and 7 institutions selected by an expert committee. RESULTS: Forty-four institutions answered the questionnaire (42% response rate). In the final analysis, 39 completed questionnaires were included. Thirty-six institutions (92%) reported that they update their guidelines. Thirty-one institutions (86%) have a formal procedure for updating their guidelines, and 19 (53%) have a formal procedure for deciding when a guideline becomes out of date. Institutions describe the process as moderately rigorous (36%) or acknowledge that it could certainly be more rigorous (36%). Twenty-two institutions (61%) alert guideline users on their website when a guideline is older than three to five years or when there is a risk of being outdated. Twenty-five institutions (64%) support the concept of "living guidelines," which are continuously monitored and updated. Eighteen institutions (46%) have plans to design a protocol to improve their guideline-updating process, and 21 (54%) are willing to share resources with other organizations. CONCLUSIONS: Our study is the first to describe the process of updating CPGs among prominent guideline institutions across the world, providing a comprehensive picture of guideline updating. There is an urgent need to develop rigorous international standards for this process and to minimize duplication of effort internationally

Early life risk factors and their cumulative effects as predictors of overweight in Spanish children

Objectives: To explore early life risk factors of overweight/obesity at age 6 years and their cumulative effects on overweight/obesity at ages 2, 4 and 6 years. Methods: Altogether 1031 Spanish children were evaluated at birth and during a 6-year follow-up. Early life risk factors included: parental overweight/obesity, parental origin/ethnicity, maternal smoking during pregnancy, gestational weight gain, gestational age, birth weight, caesarean section, breastfeeding practices and rapid infant weight gain collected via hospital records. Cumulative effects were assessed by adding up those early risk factors that significantly increased the risk of overweight/obesity. We conducted binary logistic regression models. Results: Rapid infant weight gain (OR 2.29, 99% CI 1.54–3.42), maternal overweight/obesity (OR 1.93, 99% CI 1.27–2.92), paternal overweight/obesity (OR 2.17, 99% CI 1.44–3.28), Latin American/Roma origin (OR 3.20, 99% CI 1.60–6.39) and smoking during pregnancy (OR 1.61, 99% CI 1.01–2.59) remained significant after adjusting for confounders. A higher number of early life risk factors accumulated was associated with overweight/obesity at age 6 years but not at age 2 and 4 years. Conclusions: Rapid infant weight gain, parental overweight/obesity, maternal smoking and origin/ethnicity predict childhood overweight/obesity and present cumulative effects. Monitoring children with rapid weight gain and supporting a healthy parental weight are important for childhood obesity prevention

Descemet's stripping automated endothelial keratoplasty: Past, present and future

10.1586/eop.10.18Expert Review of Ophthalmology53303-31

Comparison of eye-tracking success in laser in situ keratomileusis after flap creation with 2 femtosecond laser models

10.1016/j.jcrs.2010.10.039Journal of Cataract and Refractive Surgery373538-543JCSU

In vivo real-time intraocular pressure variations during LASIK flap creation

10.1167/iovs.10-5228Investigative Ophthalmology and Visual Science5194641-4645IOVS

Physiological increases in uncoupling protein 3 augment fatty acid oxidation and decrease reactive oxygen species production without uncoupling respiration in muscle cells

Decreased uncoupling protein (UCP)3 is associated with insulin resistance in muscle of pre-diabetic and diabetic individuals, but the function of UCP3 remains unclear. Our goal was to elucidate mechanisms underlying the negative correlation between UCP3 and insulin resistance in muscle. We determined effects of physiologic UCP3 overexpression on glucose and fatty acid oxidation and on mitochondrial uncoupling and reactive oxygen species (ROS) production in L6 muscle cells. An adenoviral construct caused a 2.2- to 2.5-fold increase in UCP3 protein. Palmitate oxidation was increased in muscle cells incubated under normoglycemic or hyperglycemic conditions, whereas adenoviral green fluorescent protein infection or chronic low doses of the uncoupler dinitrophenol had no effect. Increased UCP3 did not affect glucose oxidation, whereas dinitrophenol and insulin treatments caused increases. Basal oxygen consumption, assessed in situ using self-referencing microelectrodes, was not significantly affected, whereas dinitrophenol caused increases. Mitochondrial membrane potential was decreased by dinitrophenol but was not affected by increased UCP3 expression. Finally, mitochondrial ROS production decreased significantly with increased UCP3 expression. Results are consistent with UCP3 functioning to facilitate fatty acid oxidation and minimize ROS production. As impaired fatty acid metabolism and ROS handling are important precursors in muscular insulin resistance, UCP3 is an important therapeutic target in type 2 diabetes. <br/

The updating of clinical practice guidelines: insights from an international survey

BACKGROUND: Clinical practice guidelines (CPGs) have become increasingly popular, and the methodology to develop guidelines has evolved enormously. However, little attention has been given to the updating process, in contrast to the appraisal of the available literature. We conducted an international survey to identify current practices in CPG updating and explored the need to standardize and improve the methods. METHODS: We developed a questionnaire (28 items) based on a review of the existing literature about guideline updating and expert comments. We carried out the survey between March and July 2009, and it was sent by email to 106 institutions: 69 members of the Guidelines International Network who declared that they developed CPGs; 30 institutions included in the U.S. National Guideline Clearinghouse database that published more than 20 CPGs; and 7 institutions selected by an expert committee. RESULTS: Forty-four institutions answered the questionnaire (42% response rate). In the final analysis, 39 completed questionnaires were included. Thirty-six institutions (92%) reported that they update their guidelines. Thirty-one institutions (86%) have a formal procedure for updating their guidelines, and 19 (53%) have a formal procedure for deciding when a guideline becomes out of date. Institutions describe the process as moderately rigorous (36%) or acknowledge that it could certainly be more rigorous (36%). Twenty-two institutions (61%) alert guideline users on their website when a guideline is older than three to five years or when there is a risk of being outdated. Twenty-five institutions (64%) support the concept of "living guidelines," which are continuously monitored and updated. Eighteen institutions (46%) have plans to design a protocol to improve their guideline-updating process, and 21 (54%) are willing to share resources with other organizations. CONCLUSIONS: Our study is the first to describe the process of updating CPGs among prominent guideline institutions across the world, providing a comprehensive picture of guideline updating. There is an urgent need to develop rigorous international standards for this process and to minimize duplication of effort internationally