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Sample records for hydraulic diameter ratio

  1. Sex Dimorphism of the Heart Diameters and Cardiothoracic Ratios ...

    African Journals Online (AJOL)

    Objective: To determine gender associated differences in the cardiothoracic ratio (CTR) and heart diameters in a normal Nigerian population. Subject and Method: The normal heart diameters and cardiothoracic ratios were measured from posteroanterior (PA) chest radiographs of healthy 510 male and 508 female ...

  2. Abnormal splenic artery diameter/hepatic artery diameter ratio in cirrhosis-induced portal hypertension

    Science.gov (United States)

    Zeng, Dao-Bing; Dai, Chuan-Zhou; Lu, Shi-Chun; He, Ning; Wang, Wei; Li, Hong-Jun

    2013-01-01

    AIM: To determine an optimal cutoff value for abnormal splenic artery diameter/proper hepatic artery diameter (S/P) ratio in cirrhosis-induced portal hypertension. METHODS: Patients with cirrhosis and portal hypertension (n = 770) and healthy volunteers (n = 31) underwent volumetric computed tomography three-dimensional vascular reconstruction to measure the internal diameters of the splenic artery and proper hepatic artery to calculate the S/P ratio. The cutoff value for abnormal S/P ratio was determined using receiver operating characteristic curve analysis, and the prevalence of abnormal S/P ratio and associations between abnormal S/P ratio and major complications of portal hypertension were studied using logistic regression. RESULTS: The receiver operating characteristic analysis showed that the cutoff points for abnormal splenic artery internal diameter and S/P ratio were > 5.19 mm and > 1.40, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 74.2%, 45.2%, 97.1%, and 6.6%, respectively. The prevalence of an abnormal S/P ratio in the patients with cirrhosis and portal hypertension was 83.4%. Patients with a higher S/P ratio had a lower risk of developing ascites [odds ratio (OR) = 0.708, 95%CI: 0.508-0.986, P = 0.041] and a higher risk of developing esophageal and gastric varices (OR = 1.483, 95%CI: 1.010-2.175, P = 0.044) and forming collateral circulation (OR = 1.518, 95%CI: 1.033-2.230, P = 0.034). After splenectomy, the portal venous pressure and maximum and mean portal venous flow velocities were reduced, while the flow rate and maximum and minimum flow velocities of the hepatic artery were increased (P portal hypertension, and it can be used as an important marker of splanchnic hemodynamic disturbances. PMID:23483462

  3. Allowable pillar to diameter ratio for strategic petroleum reserve caverns.

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, Brian L.; Park, Byoung Yoon

    2011-05-01

    This report compiles 3-D finite element analyses performed to evaluate the stability of Strategic Petroleum Reserve (SPR) caverns over multiple leach cycles. When oil is withdrawn from a cavern in salt using freshwater, the cavern enlarges. As a result, the pillar separating caverns in the SPR fields is reduced over time due to usage of the reserve. The enlarged cavern diameters and smaller pillars reduce underground stability. Advances in geomechanics modeling enable the allowable pillar to diameter ratio (P/D) to be defined. Prior to such modeling capabilities, the allowable P/D was established as 1.78 based on some very limited experience in other cavern fields. While appropriate for 1980, the ratio conservatively limits the allowable number of oil drawdowns and hence limits the overall utility and life of the SPR cavern field. Analyses from all four cavern fields are evaluated along with operating experience gained over the past 30 years to define a new P/D for the reserve. A new ratio of 1.0 is recommended. This ratio is applicable only to existing SPR caverns.

  4. Usefulness of left ventricular wall thickness-to-diameter ratio in thallium-201 scintigraphy

    International Nuclear Information System (INIS)

    Manno, B.; Hakki, A.H.; Kane, S.A.; Iskandrian, A.S.

    1983-01-01

    The ratio of left ventricular wall thickness to the cavity dimension, as seen on thallium-201 images, was used in this study to predict left ventricular ejection fraction and volume. We obtained rest thallium-201 images in 50 patients with symptomatic coronary artery disease. The thickness of a normal-appearing segment of the left ventricular wall and the transverse diameter of the cavity were measured in the left anterior oblique projection. The left ventricular ejection fraction and volume in these patients were determined by radionuclide ventriculography. There was a good correlation between thickness-to-diameter ratio and ejection fraction and end-systolic volume. In 18 patients with a thickness-to-diameter ratio less than 0.70, the ejection fraction was lower than in the 16 patients with thickness-to-diameter ratio greater than or equal to 1.0. Similarly, in patients with a thickness-to-diameter ratio less than 0.70, the end-diastolic and end-systolic volume were higher than in the remaining patients with higher thickness-to-diameter ratios. All 18 patients with a thickness-to-diameter ratio less than 0.70 had ejection fractions less than 40%; 14 of 15 patients with a thickness-to-diameter ratio greater than or equal to 1.0 had an ejection fraction greater than 40%. The remaining 16 patients with a thickness-to-diameter ratio of 0.7-0.99 had intermediate ejection fractions and volumes.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

    International Nuclear Information System (INIS)

    Duignan, M; Charles Nash, C; Timothy Punch, T

    2007-01-01

    A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit

  6. Comparison of CT-Determined Pulmonary Artery Diameter, Aortic Diameter, and Their Ratio in Healthy and Diverse Clinical Conditions.

    Directory of Open Access Journals (Sweden)

    Sang Hoon Lee

    Full Text Available The main pulmonary artery diameter (mPA, aortic diameter (Ao, and the mPA/Ao ratio, easily measured using chest computed tomography (CT, provide information that enables the diagnosis and evaluation of cardiopulmonary diseases. Here, we used CT to determine the sex- and age-specific distribution of normal reference values for mPA, Ao, and mPA/Ao ratio in an adult Korean population.Data from non-contrast, ECG-gated, coronary-calcium-scoring CT images of 2,547 individuals who visited the Health Screening Center of the Severance Hospital were analyzed. Healthy individuals (n = 813 included those who do not have hypertension, diabetes, asthma, obstructive lung disease, ischemic heart disease, stroke, smoking, obesity, and abnormal CT findings. Both mPA and Ao were measured at the level of bifurcation of the main pulmonary artery.The mean mPA and Ao were 25.9 mm and 30.0 mm in healthy participants, respectively, while the mean mPA/Ao ratio was 0.87. Medical conditions associated with a larger mPA were male, obesity, smoking history, hypertension, and diabetes. A larger mPA/Ao ratio was associated with female, the obese, non-smoker, normotensive, and normal serum level of lipids, while a smaller mPA/Ao ratio was associated with older age. In healthy individuals, the 90th percentile sex-specific mPA, Ao, and mPA/Ao ratio were, 31.3 mm (95% CI 29.9-32.2, 36.8 mm (95% CI 35.7-37.5, and 1.05 (95% CI 0.99-1.07 in males, and 29.6 mm (95% CI 29.1-30.2, 34.5 mm (95% CI 34.1-34.9, and 1.03 (95% CI 1.02-1.06 in females, respectively.In the Korean population, the mean mPA reference values in male and female were 26.5 mm and 25.8 mm, respectively, while the mean mPA/Ao ratio was 0.87. These values were influenced by a variety of underlying medical conditions.

  7. Distal Ureteral Diameter Ratio is Predictive of Breakthrough Febrile Urinary Tract Infection.

    Science.gov (United States)

    Arlen, Angela M; Leong, Traci; Guidos, P Joseph; Alexander, Siobhan E; Cooper, Christopher S

    2017-12-01

    Distal ureteral diameter ratio is an objective measure that is prognostic of spontaneous resolution of vesicoureteral reflux. Along with likelihood of resolution, improved identification of children at risk for recurrent febrile urinary tract infections may impact management decisions. We evaluated the usefulness of ureteral diameter ratio as a predictive factor for breakthrough febrile urinary tract infections. Children with primary vesicoureteral reflux and detailed voiding cystourethrogram were identified. Ureteral diameter ratio was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1 and L3 vertebral bodies. Demographics, vesicoureteral reflux grade, laterality, presence/absence of bladder-bowel dysfunction, and ureteral diameter ratio were tested in univariate and multivariable analyses. Primary outcome was breakthrough febrile urinary tract infections. We analyzed 112 girls and 28 boys with a mean ± SD age of 2.5 ± 2.3 years at diagnosis. Vesicoureteral reflux was grade 1 to 2 in 64 patients (45.7%), grade 3 in 50 (35.7%), grade 4 in 16 (11.4%) and grade 5 in 10 (7.2%). Mean ± SD followup was 3.2 ± 2.7 years. A total of 40 children (28.6%) experienced breakthrough febrile urinary tract infections. Ureteral diameter ratio was significantly greater in children with (0.36) vs without (0.25) breakthrough febrile infections (p = 0.004). Controlling for vesicoureteral reflux grade, every 0.1 U increase in ureteral diameter ratio resulted in 1.7 times increased odds of breakthrough infection (95% CI 1.24 to 2.26, p urinary tract infections independent of reflux grade. Ureteral diameter ratio provides valuable prognostic information about risk of recurrent pyelonephritis and may assist with clinical decision-making. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  8. Numerical Investigation of Liquid Carryover in T-Junction with Different Diameter Ratios

    Science.gov (United States)

    Pao, William; Sam, Ban; Saieed, Ahmed; Tran, Cong Minh

    2018-03-01

    In offshore Malaysia, T-junction is installed at the production header as a compact separator to tap produced gas from reservoir as fuel gas for power generation. However, excessive liquid carryover in T-junction presents a serious operational issue because it trips the whole production platform. The primary objective of present study is to numerically investigate the liquid carryover due to formation of slug, subsequently its liquid carryover at different diameter ratio. The analyses were carried out on a model with 0.0254 m (1 inch) diameter horizontal main arm and a vertically upward side arm using Volume of Fluid Method. Three different sides to main arm diameter ratio of 1.0, 0.5 and 0.3 were investigated with different gas and liquid superficial velocities. The results showed that, while the general trend is true that smaller diameter ratio T-junction has lesser liquid take off capacity, it has a very high frequency of low liquid carryover threshold. In other words, under slug flow, smaller diameter ratio T-junction is constantly transporting liquid even though at a lesser volume in comparison to regular T-junction.

  9. High-resolution computed tomography evaluation of the bronchial lumen to vertebral body diameter and pulmonary artery to vertebral body diameter ratios in anesthetized ventilated normal cats.

    Science.gov (United States)

    Lee-Fowler, Tekla M; Cole, Robert C; Dillon, A Ray; Tillson, D Michael; Garbarino, Rachel; Barney, Sharron

    2017-10-01

    Objectives Bronchial lumen to pulmonary artery diameter (BA) ratio has been utilized to investigate pulmonary pathology on high-resolution CT images. Diseases affecting both the bronchi and pulmonary arteries render the BA ratio less useful. The purpose of the study was to establish bronchial lumen diameter to vertebral body diameter (BV) and pulmonary artery diameter to vertebral body diameter (AV) ratios in normal cats. Methods Using high-resolution CT images, 16 sets of measurements (sixth thoracic vertebral body [mid-body], each lobar bronchi and companion pulmonary artery diameter) were acquired from young adult female cats and 41 sets from pubertal female cats. Results Young adult and pubertal cat BV ratios were not statistically different from each other in any lung lobe. Significant differences between individual lung lobe BV ratios were noted on combined age group analysis. Caudal lung lobe AV ratios were significantly different between young adult and pubertal cats. All other lung lobe AV ratios were not significantly different. Caudal lung lobe AV ratios were significantly different from all other lung lobes but not from each other in both the young adult and pubertal cats. Conclusions and relevance BV ratio reference intervals determined for individual lung lobes could be applied to both young adult and pubertal cats. Separate AV ratios for individual lung lobes would be required for young adult and pubertal cats. These ratios should allow more accurate evaluation of cats with concurrent bronchial and pulmonary arterial disease.

  10. The study on length and diameter ratio of nail as preliminary design for slope stabilization

    Science.gov (United States)

    Gunawan, Indra; Silmi Surjandari, Niken; Muslih Purwana, Yusep

    2017-11-01

    Soil nailing technology has been widely applied in practice for reinforced slope. The number of studies for the effective design of nail-reinforced slopes has also increased. However, most of the previous study was focused on a safety factor of the slope; the ratio of length and diameter itself has likely never been studied before. The aim of this study is to relate the length and diameter ratio of the nail with the safety factor of the 20 m height of sand slope in the various angle of friction and steepness of the slope. Simplified Bishop method was utilized to analyze the safety factor of the slope. This study is using data simulation to calculate the safety factor of the slope with soil nailing reinforcement. The results indicate that safety factor of slope stability increases with the increase of length and diameter ratio of the nail. At any angle of friction and steepness of the slope, certain effective length and diameter ratio was obtain. These results may be considered as a preliminary design for slope stabilization.

  11. Geometric interpretation of the ratio of overall diameter to rim crest diameter for lunar and terrestrial craters.

    Science.gov (United States)

    Siegal, B. S.; Wickman, F. E.

    1973-01-01

    An empirical linear relationship has been established by Pike (1967) between the overall diameter and the rim crest diameter for rimmed, flat-floored as well as bowl-shaped, lunar and terrestrial craters formed by impact and explosion. A similar relationship for experimentally formed fluidization craters has been established by Siegal (1971). This relationship is examined in terms of the geometry of the crater and the slope angles of loose materials. The parameter varies from 1.40 to 1.65 and is found to be dependent on mean interior flat floor radius, exterior and interior rim slope angles, angle of aperture of the crater cone, and the volume fraction of crater void accounted for in the rim. The range of the observed parameter can be understood in terms of simple crater geometry by realistic values of the five parameters.

  12. Can ratio of the biggest tumor diameter to total tumor diameter be a new parameter in the differential diagnosis of agressive and favorable multifocal papillary thyroid microcarcinoma?

    Science.gov (United States)

    Tam, Abbas Ali; Özdemir, Didem; Çuhacı, Neslihan; Başer, Hüsniye; Dirikoç, Ahmet; Aydın, Cevdet; Yazgan, Aylin Kılıç; Ersoy, Reyhan; Çakır, Bekir

    2017-02-01

    In this study, we aimed to evaluate the usefulness of a new parameter -ratio of the biggest tumor diameter to total tumor diameter- for the differentiation of agressive and favorable papillary thyroid microcarcinomas (PTMC). The diameter of the biggest tumor focus was taken as the primary tumor diameter. Total tumor diameter was calculated as the sum of the maximal diameter of each lesion. Ratio of primary tumor diameter to total tumor diameter was defined as tumor diameter ratio (TDR). Positive and negative predictive value, sensitivity and specificity of TDR to predict capsular invasion, extrathyroidal extension (ETE) and lymph node metastasis (LNM) were determined. Mean TDR was significantly lower in multifocal PTMC patients with capsular invasion, ETE, lymphovascular invasion and LNM compared to patients without these features. The sensitivities of TDR for the detection of LNM, ETE and capsular invasion were 100%, 100% and 94.2%, respectively. Specificity of TDR was 86.2% for LNM, 88% for ETE and 94.7% for capsular invasion. Best cut off values of TDR that can predict capsular invasion, ETE and LNM in multifocal PTMC were 0.62, 0.57 and 0.56, respectively. Multifocal papillary thyroid carcinoma patients with capsular invasion, ETE and LNM had significantly lower mean TDR when compared to ones without these features. Decreased TDR was associated with capsular invasion, ETE and LNM in patients with multifocal PTMC and PTC. This new parameter might be particularly helpful for the detection of aggressive behavior in multifocal PTMCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Experimental tests of the effect of rotor diameter ratio and blade number to the cross-flow wind turbine performance

    Science.gov (United States)

    Susanto, Sandi; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi

    2018-02-01

    Cross-flow wind turbine is one of the alternative energy harvester for low wind speeds area. Several factors that influence the power coefficient of cross-flow wind turbine are the diameter ratio of blades and the number of blades. The aim of this study is to find out the influence of the number of blades and the diameter ratio on the performance of cross-flow wind turbine and to find out the best configuration between number of blades and diameter ratio of the turbine. The experimental test were conducted under several variation including diameter ratio between outer and inner diameter of the turbine and number of blades. The variation of turbine diameter ratio between inner and outer diameter consisted of 0.58, 0.63, 0.68 and 0.73 while the variations of the number of blades used was 16, 20 and 24. The experimental test were conducted under certain wind speed which are 3m/s until 4 m/s. The result showed that the configurations between 0.68 diameter ratio and 20 blade numbers is the best configurations that has power coefficient of 0.049 and moment coefficient of 0.185.

  14. Influence of length-to-diameter ratio on shrinkage of basalt fiber concrete

    Science.gov (United States)

    Ruijie, MA; Yang, Jiansen; Liu, Yuan; Zheng, Xiaojun

    2017-09-01

    In order to study the shrinkage performance of basalt concrete, using the shrinkage rate as index, the work not only studied the influence of different length-to-diameter ratio (LDR) on plastic shrinkage and drying shrinkage of basalt fiber concrete, but also analyzed the action mechanism. The results show that when the fiber content is 0.1%, the LDR of 800 and 1200 take better effects on reducing plastic shrinkage, however the fiber content is 0.3%, that of LDR 600 is better. To improve drying shrinkage, the fiber of LDR 800 takes best effect. In the concrete structure, the adding basalt fibers form a uniform and chaotic supporting system, optimize the pore and the void structure of concrete, make the material further compacted, reduce the water loss, so as to decrease the shrinkage of concrete effectively.

  15. A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.

    Science.gov (United States)

    Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

    2010-03-01

    The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. 2009 Elsevier Ltd. All rights reserved.

  16. Lock-on characteristics behind two side-by-side cylinders of diameter ratio two at small gap ratio

    Science.gov (United States)

    Lee, Petry Y. R.; Lu, Wei-Ting; Chou, Shy-Tsin; Kuo, Cheng-Hsiung

    2012-10-01

    The lock-on characteristics, the detailed interactions and downstream evolutions of the wakes behind side-by-side cylinders of unequal diameter ( D/ d = 2), spaced by a gap ratio 0.75 ( G/ D = 0.75), are investigated at Reynolds number 600 by the dye flow visualization, laser Doppler anemometry (LDA) and particle image velocimeter (PIV) velocity measurements. The lock-on frequency bands are studied by LDA and PIV at Reynolds number 2,000. The D, d and G are the diameters of the large, the small cylinders and the net gap between two cylinders, respectively. Periodic excitations, in form of rotary oscillation about the cylinder center, are applied to the large cylinder with the same amplitude. It is found that while the large cylinder is excited, two lock-on frequency bands of the wake behind the large cylinder are detected. These two lock-on frequency bands correspond to the primary and the one-third sub-harmonic lock-on of the wake behind large cylinder, respectively. These two lock-on frequency bands distribute symmetrically about the fundamental and the third superharmonic of the natural shedding frequency behind a single cylinder at the same Reynolds number. The left-shifted frequency band (1.8 ≤ f e / f os ≤ 2.0) is not considered as a locked-on frequency band because the phase difference between two excitation frequencies across f e / f os = 2.0 vary significantly. While the wake behind the large cylinder is locked-on at f e /3 (or f os ), the gap flow becomes unbiased and the frequency of the wake behind small cylinder remains around the natural shedding frequency. Thus, the frequency band of 3.0 ≤ f e / f os ≤ 3.22 is also not locked-on because the phase difference in the narrow wake excited at f e / f os = 2.93 and 3.07 changes significantly. Note f e and f os denote the excitation frequency and the natural shedding frequency behind a single large cylinder, respectively.

  17. Lock-on characteristics behind two side-by-side cylinders of diameter ratio two at small gap ratio

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Petry Y.R.; Lu, Wei-Ting; Chou, Shy-Tsin; Kuo, Cheng-Hsiung [National Chung Hsing University, Department of Mechanical Engineering, Taichung (China)

    2012-10-15

    The lock-on characteristics, the detailed interactions and downstream evolutions of the wakes behind side-by-side cylinders of unequal diameter (D/d = 2), spaced by a gap ratio 0.75 (G/D = 0.75), are investigated at Reynolds number 600 by the dye flow visualization, laser Doppler anemometry (LDA) and particle image velocimeter (PIV) velocity measurements. The lock-on frequency bands are studied by LDA and PIV at Reynolds number 2,000. The D, d and G are the diameters of the large, the small cylinders and the net gap between two cylinders, respectively. Periodic excitations, in form of rotary oscillation about the cylinder center, are applied to the large cylinder with the same amplitude. It is found that while the large cylinder is excited, two lock-on frequency bands of the wake behind the large cylinder are detected. These two lock-on frequency bands correspond to the primary and the one-third sub-harmonic lock-on of the wake behind large cylinder, respectively. These two lock-on frequency bands distribute symmetrically about the fundamental and the third superharmonic of the natural shedding frequency behind a single cylinder at the same Reynolds number. The left-shifted frequency band (1.8 {<=} f{sub e} /f{sub os} {<=} 2.0) is not considered as a locked-on frequency band because the phase difference between two excitation frequencies across f{sub e} /f{sub os} = 2.0 vary significantly. While the wake behind the large cylinder is locked-on at f{sub e} /3 (or f{sub os}), the gap flow becomes unbiased and the frequency of the wake behind small cylinder remains around the natural shedding frequency. Thus, the frequency band of 3.0 {<=} f{sub e} /f{sub os} {<=} 3.22 is also not locked-on because the phase difference in the narrow wake excited at f{sub e} /f{sub os} = 2.93 and 3.07 changes significantly. Note f{sub e} and f{sub os} denote the excitation frequency and the natural shedding frequency behind a single large cylinder, respectively. (orig.)

  18. Effect of chord-to-diameter ratio on vertical-axis wind turbine wake development

    Science.gov (United States)

    Parker, Colin M.; Araya, Daniel B.; Leftwich, Megan C.

    2017-12-01

    The wake structure of a vertical-axis wind turbine (VAWT) is strongly dependent on the tip-speed ratio, λ, or the tangential speed of the turbine blade relative to the incoming wind speed. The geometry of a turbine can influence λ, but the precise relationship among VAWT geometric parameters and VAWT wake characteristics remains unknown. To investigate this relationship, we present the results of an experiment to characterize the wakes of three VAWTs that are geometrically similar except for the ratio of the turbine diameter ( D), to blade chord ( c), which was chosen to be D/c = 3, 6, and 9. For a fixed freestream Reynolds number based on the blade chord of Re_c = 1.6× 10^3, both two-component particle image velocimetry (PIV) and single-component hot-wire anemometer measurements are taken at the horizontal mid-plane in the wake of each turbine. PIV measurements are ensemble averaged in time and phase averaged with each rotation of the turbine. Hot-wire measurement points are selected to coincide with the edge of the shear layer of each turbine wake, as deduced from the PIV data, which allows for an analysis of the frequency content of the wake due to vortex shedding by the turbine.

  19. Validation of the ureteral diameter ratio for predicting early spontaneous resolution of primary vesicoureteral reflux.

    Science.gov (United States)

    Arlen, Angela M; Kirsch, Andrew J; Leong, Traci; Cooper, Christopher S

    2017-08-01

    Management of primary vesicoureteral reflux (VUR) remains controversial, and reflux grade currently constitutes an important prognostic factor. Previous reports have demonstrated that distal ureteral diameter ratio (UDR) may be more predictive of outcome than vesicoureteral reflux (VUR) grade. We performed an external validation study in young children, evaluating early spontaneous resolution rates relative to reflux grade and UDR. Voiding cystourethrograms (VCUGs) were reviewed. UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between the L1 and L3 vertebral bodies (Figure). VUR grade and UDR were tested in univariate and multivariable analyses. Primary outcome was status of VUR at last clinical follow-up (i.e. resolution, persistence, or surgical intervention). Demographics, VUR timing, laterality, and imaging indication were also assessed. One-hundred and forty-seven children (98 girls, 49 boys) were diagnosed with primary VUR at a mean age of 5.5 ± 4.7 months. Sixty-seven (45.6%) resolved spontaneously, 55 (37.4%) had persistent disease, and 25 (17%) were surgically corrected. Patients who spontaneously resolved had significantly lower VUR grade, refluxed later during bladder filling, and had significantly lower UDR. In a multivariable model, grade of VUR (p = 0.001), age early spontaneous resolution than grade alone. Furthermore, unlike traditional VUR grading where children with grade 1-5 may outgrow reflux depending on other factors, there appears to be a consistent UDR cutoff whereby patients are unlikely to resolve. In the present study, no child with a UDR greater than 0.43 experienced early spontaneous resolution, and only three (4.5%) of those with spontaneous resolution had a UDR above 0.35. UDR correlates with reflux grade, and is predictive of early resolution in children with primary VUR. UDR is an objective measurement of VUR, and provides valuable prognostic information about spontaneous

  20. Numerical simulation of two-phase slug flow with liquid carryover in different diameter ratio T-junction

    Science.gov (United States)

    Pao, W.; Hon, L.; Saieed, A.; Ban, S.

    2017-10-01

    A smaller diameter conduit pointing at 12 o’clock position is typically hot-tapped to a horizontal laying production header in offshore platform to tap produced gas for downstream process train. This geometric feature is commonly known as T-junction. The nature of multiphase fluid splitting at the T-junction is a major operational challenge due to unpredictable production environment. Often, excessive liquid carryover occurs in the T-junction, leading to complete platform trip and halt production. This is because the downstream process train is not designed to handle excessive liquid. The objective of this research is to quantify the effect of different diameter ratio on phase separation efficiency in T-junction. The liquid carryover is modelled as two-phase air-water flow using Eulerian Mixture Model coupled with Volume of Fluid Method to mimic the slug flow in the main pipe. The focus in this paper is 0.0254 m (1 inch) diameter horizontal main arm and vertical branch arm with diameter ratio of 1.0, 0.5 and 0.3. The present research narrowed the investigation to only slug flow regime using Baker’s map as reference. The investigation found that, contrary to common believe, smaller diameter ratio T-junction perform worse than larger diameter ratio T-junction.

  1. Usefulness of meniscal width to transverse diameter ratio on coronal MRI in the diagnosis of incomplete discoid lateral meniscus

    International Nuclear Information System (INIS)

    Park, H.J.; Lee, S.Y.; Park, N.-H.; Chung, E.C.; Park, J.Y.; Kim, M.S.; Lee, E.J.

    2014-01-01

    Aim: To evaluate the clinical utility of the meniscal width to transverse diameter ratio (L/M ratio) of the lateral meniscus in the diagnosis of incomplete discoid lateral meniscus (IDLM) as compared with the arthroscopic diagnosis, meniscal width to tibial diameter ratio (L/T ratio) and conventional lateral meniscus width criteria. Materials and methods: This retrospective study sample included 41 patients with IDLM who underwent knee magnetic resonance imaging (MRI) and arthroscopy, as well as 50 controls with normal lateral menisci. MRI examinations were interpreted independently by two radiologists, both of whom were blinded to clinical information and radiological reports. Assessment of meniscal width (L), maximal transverse diameter of the lateral meniscus (M), and transverse diameter of the tibia (T) was carried out on central coronal sections that were observed to pass through the medial collateral ligament. L/M and L/T ratios were calculated. These results were correlated with arthroscopic findings and analysed statistically using categorical regression analysis and non-parametric correlation analysis. Using arthroscopic findings as the standard of reference, sensitivity and specificity were calculated for: (1) 12, 13, 14, and 15 mm meniscal width thresholds; (2) 40%, 50%, 60%, and 70% L/M ratio thresholds; and (3) 15%, 18%, 20%, and 25% L/T ratio thresholds. Results: The mean L/M ratio of the IDLM was approximately 67% and was statistically significantly higher than the control (44%). The best diagnostic discrimination was achieved using a threshold of 50%. The mean L/T ratio of the IDLM was approximately 23% and was statistically significant. The best diagnostic discrimination was achieved using a threshold of 18%. The threshold of 13 mm of meniscal width also showed high sensitivity and high specificity. Conclusion: The use of the L/M ratio or L/T ratio in combination with meniscal width criteria may be a useful method for evaluating IDLM

  2. A void ratio dependent water retention curve model including hydraulic hysteresis

    Directory of Open Access Journals (Sweden)

    Pasha Amin Y.

    2016-01-01

    Full Text Available Past experimental evidence has shown that Water Retention Curve (WRC evolves with mechanical stress and structural changes in soil matrix. Models currently available in the literature for capturing the volume change dependency of WRC are mainly empirical in nature requiring an extensive experimental programme for parameter identification which renders them unsuitable for practical applications. In this paper, an analytical model for the evaluation of the void ratio dependency of WRC in deformable porous media is presented. The approach proposed enables quantification of the dependency of WRC on void ratio solely based on the form of WRC at the reference void ratio and requires no additional parameters. The effect of hydraulic hysteresis on the evolution process is also incorporated in the model, an aspect rarely addressed in the literature. Expressions are presented for the evolution of main and scanning curves due to loading and change in the hydraulic path from scanning to main wetting/drying and vice versa as well as the WRC parameters such as air entry value, air expulsion value, pore size distribution index and slope of the scanning curve. The model is validated using experimental data on compacted and reconstituted soils subjected to various hydro-mechanical paths. Good agreement is obtained between model predictions and experimental data in all the cases considered.

  3. Nitrogen removal in permeable woodchips filters affected by hydraulic loading rate and woodchips ratio

    DEFF Research Database (Denmark)

    Bruun, Jacob Druedahl; Kjærgaard, Charlotte; Hoffmann, Carl Christian

    2016-01-01

    response of mixed reactive media (woodchips-Seashells and woodchips-Filtralite mixtures) at two woodchips ratios (WR) to changes in the hydraulic loading rate (HLR). The tests implied continuous loading of aerated NO3-N spiked artificial drainage water and tritium (3H2O) breakthrough experiments. Flow...... normalized nitrate reduction rates were 0.35-3.97 g N m-3 L-1, corresponding to N- removal efficiencies of 5 to 74% depending on HLR and filter mixtures. At high HLR oxic conditions prevailed, thus N removal was restricted to the immobile domain, controlled by diffusion. At lower HLR, progressively lower...

  4. Analysis of in-R12 CHF data: influence of hydraulic diameter and heating length; test of Weisman boiling crisis model

    International Nuclear Information System (INIS)

    Czop, V.; Herer, C.; Souyri, A.; Garnier, J.

    1993-09-01

    In order to progress on the comprehensive modelling of the boiling crisis phenomenon, Electricite de France (EDF), Commissariat a l'Energie Atomique (CEA) and FRAMATOME have set up experimental programs involving in-R12 tests: the EDF APHRODITE program and the CEA-EDF-FRAMATOME DEBORA program. The first phase in these programs aims to acquire critical heat flux (CHF) data banks, within large thermal-hydraulic parameter ranges, both in cylindrical and annular configurations, and with different hydraulic diameters and heating lengths. Actually, three data banks have been considered in the analysis, all of them concerning in-R12 round tube tests: - the APHRODITE data bank, obtained at EDF with a 13 mn inside diameter, - the DEBORA data bank, obtained at CEA with a 19.2 mm inside diameter, - the KRISTA data bank, obtained at KfK with a 8 mm inside diameter. The analysis was conducted using CHF correlations and with the help of an advanced mathematical tool using pseudo-cubic thin plate type Spline functions. Two conclusions were drawn: -no influence of the heating length on our CHF results, - the influence of the diameter on the CHF cannot be simply expressed by an exponential function of this parameter, as thermal-hydraulic parameters also have an influence. Some calculations with Weisman and Pei theoretical boiling crisis model have been compared to experimental values: fairly good agreement was obtained, but further study must focus on improving the modelling of the influence of pressure and mass velocity. (authors). 12 figs., 4 tabs., 21 refs

  5. An experimental study on single phase convection heat transfer and pressure drop in two brazed plate heat exchangers with different chevron shapes and hydraulic diameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Man Bae; Park, Chang Yong [Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2017-05-15

    An experimental study on heat transfer and pressure drop characteristics was performed at single phase flow in two Brazed plate heat exchangers (BPHEs) with different geometries. The corrugation density of one of the BPHE (Type II) was two times as high as that of the other BPHE (Type I). The hydraulic diameter of the type II BPHE was 2.13 mm, which was 38 % smaller than that of the type I BPHE. Also, the cross section shape of the flow channels for the type II BPHE was different from that for conventional BPHEs due to the unusual corrugation patterns and brazing points. The experimental conditions for temperatures were varied from 4.6 °C to 49.1 °C, and for mass flow rates were changed from 0.07 kg/s to 1.24 kg/s. The measured results showed that pressure drop in the type II BPHE was about 110 % higher than that in the type I BPHE. Nu of the type II was higher than that of the type I BPHE and the enhancement became larger with the increase of Re at the ranges above 800. New correlations for fF and Nu were proposed by this study and their prediction accuracy could be improved by considering the surface enlargement factor in the correlations. The performance evaluation of the two BPHEs was performed by (j/f{sub F}1{sup /3}) which represented the ratio of heat transfer and pressure drop performance. Also, a new parameter, the capacity compactness of PHE, was proposed and it presented the PHE capacity per unit volume and unit log mean temperature difference. The comparison showed that the two BPHEs had similar values of the (j/f{sub F}1{sup /3}), whereas they had significantly different values of the capacity compactness. The capacity compactness of the type II BPHE was 1.5 times higher than that for the type I BPHE.

  6. An experimental study on single phase convection heat transfer and pressure drop in two brazed plate heat exchangers with different chevron shapes and hydraulic diameters

    International Nuclear Information System (INIS)

    Kim, Man Bae; Park, Chang Yong

    2017-01-01

    An experimental study on heat transfer and pressure drop characteristics was performed at single phase flow in two Brazed plate heat exchangers (BPHEs) with different geometries. The corrugation density of one of the BPHE (Type II) was two times as high as that of the other BPHE (Type I). The hydraulic diameter of the type II BPHE was 2.13 mm, which was 38 % smaller than that of the type I BPHE. Also, the cross section shape of the flow channels for the type II BPHE was different from that for conventional BPHEs due to the unusual corrugation patterns and brazing points. The experimental conditions for temperatures were varied from 4.6 °C to 49.1 °C, and for mass flow rates were changed from 0.07 kg/s to 1.24 kg/s. The measured results showed that pressure drop in the type II BPHE was about 110 % higher than that in the type I BPHE. Nu of the type II was higher than that of the type I BPHE and the enhancement became larger with the increase of Re at the ranges above 800. New correlations for fF and Nu were proposed by this study and their prediction accuracy could be improved by considering the surface enlargement factor in the correlations. The performance evaluation of the two BPHEs was performed by (j/f F 1 /3 ) which represented the ratio of heat transfer and pressure drop performance. Also, a new parameter, the capacity compactness of PHE, was proposed and it presented the PHE capacity per unit volume and unit log mean temperature difference. The comparison showed that the two BPHEs had similar values of the (j/f F 1 /3 ), whereas they had significantly different values of the capacity compactness. The capacity compactness of the type II BPHE was 1.5 times higher than that for the type I BPHE.

  7. Optimization study on pin tip diameter of an impact-pin nozzle at high pressure ratio

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, C. Palani; Lee, Kwon Hee [FMTRC, Daejoo Machinery Co. Ltd., Daegu (Korea, Republic of); Park, Tae Choon; Cha, Bong Jun [Engine Components Research Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Kim, Heuy Dong [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of)

    2016-09-15

    Wet compression system is typically installed in a gas turbine engine to increase the net power output and efficiency. A crucial component of the wet compression system is the nozzle which generates fine water droplets for injection into the compressor. The main objective of present work is to optimize a kind of nozzle called impact-pin spray nozzle and thereby produce better quality droplets. To achieve this, the dynamics occurring in the water jet impinging on the pin tip, the subsequent formation of water sheet, which finally breaks into water droplets, must be studied. In this manuscript, the progress on the numerical studies on impact-pin nozzle are reported. A small computational domain covering the orifice, pin tip and the region where primary atomization occurs is selected for numerical analysis. The governing equations are selected in three dimensional cartesian form and simulations are performed to predict the dynamics of water jet impinging on the pin. Systematic studies were carried out and the results leading to the choice of turbulence model and the effect of pin tip diameter are reported here. Further studies are proposed to show the future directions of the present research work.

  8. Experiments on hydraulically-compensated Compressed Air Energy Storage (CAES) system using large-diameter vertical pipe two-phase flow test facility: test facility and test procedure

    International Nuclear Information System (INIS)

    Ohtsu, Iwao; Murata, Hideo; Kukita, Yutaka; Kumamaru, Hiroshige.

    1996-07-01

    JAERI, the University of Tokyo, the Central Research Institute of Electric Power Industry and Shimizu Corporation jointing performed and experimental study on two-phase flow in the hydraulically-compensated Compressed Air Energy Storage (CAES) system with a large-diameter vertical pipe two-phase flow test facility from 1993 to 1995. A hydraulically-compensated CAES system is a proposed, conceptual energy storage system where energy is stored in the form of compressed air in an underground cavern which is sealed by a deep (several hundred meters) water shaft. The shaft water head maintains a constant pressure in the cavern, of several mega Pascals, even during loading or unloading of the cavern with air. The dissolved air in the water, however, may create voids in the shaft when the water rises through the shaft during the loading, being forced by the air flow into the cavern. The voids may reduce the effective head of the shaft, and thus the seal may fail, if significant bubbling should occur in the shaft. This bubbling phenomenon (termed 'Champaign effect') and potential failure of the water seal ('blowout') are simulated in a scaled-height, scaled-diameter facility. Carbon dioxide is used to simulate high solubility of air in the full-height, full-pressure system. This report describes the expected and potential two-phase flow phenomena in a hydraulically-compensated CAES system, the test facility and the test procedure, a method to estimate quantities which are not directly measured by using measured quantities and hydrodynamic basic equations, and desirable additional instrumentation. (author)

  9. Automated detection and classification of major retinal vessels for determination of diameter ratio of arteries and veins

    Science.gov (United States)

    Muramatsu, Chisako; Hatanaka, Yuji; Iwase, Tatsuhiko; Hara, Takeshi; Fujita, Hiroshi

    2010-03-01

    Abnormalities of retinal vasculatures can indicate health conditions in the body, such as the high blood pressure and diabetes. Providing automatically determined width ratio of arteries and veins (A/V ratio) on retinal fundus images may help physicians in the diagnosis of hypertensive retinopathy, which may cause blindness. The purpose of this study was to detect major retinal vessels and classify them into arteries and veins for the determination of A/V ratio. Images used in this study were obtained from DRIVE database, which consists of 20 cases each for training and testing vessel detection algorithms. Starting with the reference standard of vasculature segmentation provided in the database, major arteries and veins each in the upper and lower temporal regions were manually selected for establishing the gold standard. We applied the black top-hat transformation and double-ring filter to detect retinal blood vessels. From the extracted vessels, large vessels extending from the optic disc to temporal regions were selected as target vessels for calculation of A/V ratio. Image features were extracted from the vessel segments from quarter-disc to one disc diameter from the edge of optic discs. The target segments in the training cases were classified into arteries and veins by using the linear discriminant analysis, and the selected parameters were applied to those in the test cases. Out of 40 pairs, 30 pairs (75%) of arteries and veins in the 20 test cases were correctly classified. The result can be used for the automated calculation of A/V ratio.

  10. Comparison of Heidelberg Retina Tomograph with disc-macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia.

    Science.gov (United States)

    Pang, Yi; Frantz, Kelly A

    2016-05-01

    To evaluate whether Heidelberg Retinal Tomograph (HRT) is a valid test for diagnosing congenital optic nerve hypoplasia (CONH) compared to the ratio of the distance between the centre of the optic disc and the centre of the macula and the mean optic disc diameter (DM:DD ratio). Furthermore, to determine the optimal cut-off value of HRT disc area to differentiate a hypoplastic disc from a normal optic disc. A total of 33 subjects with CONH (4-67 years old) and 160 normal subjects (5-65 years old) were recruited and underwent comprehensive eye examinations, fundus photography and HRT. Receiver operating characteristic curves for DM:DD ratio and HRT disc area were constructed based on data from the 46 CONH eyes and 160 control eyes. Mean (±S.D.) HRT disc area was 1.94 (±0.54) mm(2) for the control eyes and 0.84 (±0.35) mm(2) for the CONH eyes (p < 0.0001). The area under the curve (AUC) for DM:DD ratio was 0.83 (95% confidence interval: 0.76-0.90). The AUC for HRT disc area was 0.96 (95% confidence interval: 0.94-0.99). A statistically significant difference was found between AUC for HRT disc area and that for DM:DD ratio (p = 0.0004). The optimal cut-off value for HRT disc area was 1.42 mm(2) with 95% sensitivity and 85% specificity. The optimal cut-off value for DM:DD ratio was 3.20 with 78% sensitivity and 78% specificity. Both HRT and the DM:DD ratio are valid tests to aid diagnosis of CONH. HRT is superior to DM:DD ratio in diagnosing CONH with higher sensitivity and specificity. We suggest the optimal cut-off value for HRT disc area as 1.42 mm(2) in order to discriminate a hypoplastic disc from a normal optic disc. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  11. Study on two phase flow characteristics in annular pulsed extraction column with different ratio of annular width to column diameter

    International Nuclear Information System (INIS)

    Qin Wei; Dai Youyuan; Wang Jiading

    1994-01-01

    Annular pulsed extraction column can successfully provide large throughput and can be made critically safe for fuel reprocessing. This investigation is to study the two phase flow characteristics in annular pulsed extraction column with four different annular width. 30% TBP (in kerosene)-water is used (water as continuous phase). Results show that modified Pratt correlation is valid under the experimental operation conditions for the annular pulsed extraction column. The characteristic velocity U K decreased with the increase of energy input and increased with the increase of the ratio of annular width to column diameter. Flooding velocity correlation is suggested. The deviation of the calculated values from the experimental data is within +20% for four annular width in a pulsed extraction column

  12. Mapping Variability in the Medusae Fossae Formation: Yardang Morphologies, Fluvial Reworking, and Crater Depth to Diameter Ratios

    Science.gov (United States)

    Khuller, A. R.; Kerber, L.

    2017-12-01

    The Medusae Fossae Formation (MFF) is a voluminous, fine-grained deposit thought to be of pyroclastic origin. While it contains widespread, well-preserved inverted fluvial features, its pervasive cover of dust means that little is known about its composition, and indirect means must be used to characterize its material properties. This project aims to correlate fluvial features in the Western MFF with other indicators of material strength: yardang morphology and crater depth-to-diameter ratios. For this work, Context Camera (CTX) images were used to map features of fluvial origin (inverted channels, sinuous ridges, alluvial fans). The presence of rounded, meso-yardangs in close proximity to fluvial features was also mapped. Crater depth-diameter (d/D) ratios (for craters 1-512km) were analyzed using a global Mars crater database (Robbins and Hynek, 2012) as a proxy for material strength. Approximately 1400 fluvial segments were mapped, with the most populous cluster located in Aeolis and Zephyria Plana. Rounded meso-yardangs were found to be common in areas that also have fluvial features. In agreement with previous work (Barlow, 1993), MFF craters were found to have a greater d/D ratio (0.0523) than the global mean (0.0511). Ratios between MFF lobes differ significantly, providing insight into the heterogeneity of induration within the formation. The deepest craters are found in Eumenides Dorsum and the shallowest in Aeolis Planum, consistent with a greater degree of induration and reworking in the western part of the formation where the fluvial features and "salt-playa" meso-yardangs are found. It also suggests that Eumenides, which is the tallest MFF outcrop, could also be the least compacted. The presence of long, complex, and sometimes overlapping branching networks imply multiple relative episodes of channel formation. Rounded meso-yardangs, which are associated with salt playa surfaces on Earth, provide additional evidence for the presence of liquid water

  13. SU-E-I-28: Introduction and Investigation of Effective Diameter Ratios as a New Patient Size Metric for Use in CT

    Energy Technology Data Exchange (ETDEWEB)

    Lamoureux, R [Gainesville, FL (United States); Sinclair, L [Portland, OR (United States); Mench, A [Salem Health, Tualatin, OR (United States); Lipnharski, I; Carranza, C; Bidari, S [University of Florida, Gainesville, FL (United States); Cormack, B [UF Health, Gainesville, FL (United States); Rill, L [Univ Florida, Jacksonville Beach, FL (United States); Arreola, M [University of Florida Health Science Center, Gainesville, FL (United States)

    2015-06-15

    Purpose: To introduce and investigate effective diameter ratios as a new patient metric for use in computed tomography protocol selection as a supplement to patient-specific size parameter data. Methods: The metrics of outer effective diameter and inner effective diameter were measured for 7 post-mortem subjects scanned with a standardized chest/abdomen/pelvis (CAP) protocol on a 320-slice MDCT scanner. The outer effective diameter was calculated by obtaining the anterior/posterior and lateral dimensions of the imaged anatomy at the middle of the scan range using Effective Diameter= SQRT(AP height*Lat Width). The inner effective diameter was calculated with the same equation using the AP and Lat dimensions of the anatomy excluding the adipose tissue. The ratio of outer to inner effective diameter was calculated for each subject. A relationship to BMI, weight, and CTDI conversion coefficients was investigated. Results: For the largest subject with BMI of 43.85 kg/m2 and weight of 255 lbs the diameter ratio was calculated as 1.33. For the second largest subject with BMI of 33.5 kg/m2 and weight of 192.4 lbs the diameter ratio was measured as 1.43, indicating a larger percentage of adipose tissue in the second largest subject’s anatomical composition. For the smallest subject at BMI of 17.4 kg/m2 and weight of 86 lbs a similar tissue composition was indicated as a subject with BMI of 24.2 kg/m2 and weight of 136 lbs as they had the same diameter ratios of 1.11. Conclusion: The diameter ratio proves to contain information about anatomical composition that the BMI and weight alone do not. The utility of this metric is still being examined but could prove useful for determining MDCT techniques and for giving a more in depth detail of the composition of a patient’s body habitus.

  14. Reference interval for the disc-macula distance to disc diameter ratio in a large population of healthy Japanese adults

    Science.gov (United States)

    Sato, Ken-ichi

    2017-01-01

    Abstract This study presents the calculated reference interval for the disc-to-macula distance to disc diameter ratio (DM:DD) based on a large population of healthy Japanese adults. A total of 308 consecutive, healthy Japanese adults were examined in this prospective observational study. Eighteen subjects were also excluded because of poor quality of the fundus photograph of one or both eyes; 290 (161 men and 129 women) were included in this study. For each subject, a color fundus photograph of one eye, either the right or left, was randomly selected and used for analysis. On the photograph, the distances between the fovea and the nearest temporal margin of the optic disc (Dft), and the two kinds of disc diameters (D1 and D2), which bisected at right angles and one of which was directed to the fovea (D1), were measured. DM:DD was estimated using the formula: (2Dft + D1)/(D1 + D2). The mean ± standard deviation of DM:DD was 2.91 ± 0.49 for men and 2.96 ± 0.54 for women; there was no sex difference (P = .78, Mann–Whitney U test). Also, almost no relationship was found between DM:DD and age (ρ = −.12, P = .04, Spearman's rank correlation coefficient). The data did not fit a normal distribution (P < .001, Kolmogorov–Smirnov test). The estimated reference interval for DM:DD corresponding to the 2.5th and 97.5th percentiles was 2.12 to 4.18. Using a nonparametric approach, the reference interval for DM:DD of a large population of healthy Japanese adults was calculated to be 2.12 to 4.18, regardless of age or sex. PMID:28403107

  15. The population distribution of the sagittal abdominal diameter (SAD) and SAD/height ratio among Finnish adults.

    Science.gov (United States)

    Kahn, H S; Rissanen, H; Bullard, K M; Knekt, P

    2014-12-01

    Sagittal abdominal diameter (SAD; 'abdominal height' measured in supine position) may improve upon conventional anthropometry for predicting incident cardiometabolic diseases. However, the SAD is used infrequently by practitioners and epidemiologists. A representative survey of Finnish adults in 2000-2001 collected body measurements including SAD (by sliding-beam calliper) using standardized protocols. Sampled non-pregnant adults (ages 30+ years; 79% participation) provided 6123 SAD measurements from 80 health centre districts. Through stratified, complex survey design, these data represented 2.86 million adults at ages 30+ years. SAD ranged from 13.5 to 38.0 cm, with a population mean (standard error) of 21.7 (0.05) cm and median (interquartile range) of 21.0 (19.1-23.4). Median SAD was higher at ages 50+ years compared with ages 30-49 both for men (22.4 [20.5-24.6] vs. 20.8 [19.3-22.7]) and women (21.7 [19.6-23.9] vs. 19.4 [17.8-21.4]). The SAD/height ratio was similar (0.118) for both sexes at 30-39 years, rising more steeply with age for women than men. Attaining only a basic education, compared with a high level, was associated with increased mean (95% confidence interval) SADs for men (22.6 [22.3-22.8] vs. 22.0 [21.7-22.2]) and women (21.8 [21.5-22.0] vs. 20.6 [20.4-20.8]). Finland's early experience with nationally representative SAD measurements provides normative reference values and physiological insights useful for investigations of cardiometabolic risk. © 2014 World Obesity.

  16. Kerosene-water separation in T-junction with orientation upward branch with a 60° angle: Variation of diameter ratio

    Science.gov (United States)

    Puspitasari, Dewi; Indarto, Purnomo, Khasani

    2016-06-01

    Research on the T-junction is still underway for the flow of liquid-liquid (kerosene-water). Some research on the characteristics of kerosene-water separation was performed using T-junction oriented upward branch with a 60° angle. To observe the effect of diameters ratio on the phase separation that produced T-junction then made a test section with a horizontal pipe diameter 36 mm, while the side arm 36 mm diameter, 26 mm and 19 mm (diameters ratio of 1, 0.7 and 0.5) by using plexiglass pipe type. Based on experimental results and visualization of data flow in the test section, to the value obtained 60% water cut, the maximum separation efficiency of 94%, FK = 0.94 and FW = 0.001 with a diameter ratio of 1. For other diameter ratio of 0.7 and 0.5 respectively separation efficiency of 66%, FK = 1 and Fw = 0.34 for 0.7 and separation efficiency of 84%, FK = 1 and Fw = 0.16 for 0.5, the best value is obtained at a water cut 60% too. All the best conditions to achieve the above-stratified flow pattern.

  17. Evaluation of right atrium-to-right ventricle diameter ratio on computed tomography pulmonary angiography: Prediction of adverse outcome and 30-day mortality.

    Science.gov (United States)

    Oz, Ibrahim Ilker; Altınsoy, Bülent; Serifoglu, Ismail; Sayın, Rasit; Buyukuysal, Mustafa Cagatay; Erboy, Fatma; Akduman, Ece Isin

    2015-12-01

    The aim of this study was to examine the association between right atrium (RA) and right ventricle (RV) diameters on computed tomography (CT) pulmonary angiography in response to acute pulmonary embolism (APE), in addition to 30-day mortality and adverse outcomes in patients with APE. This retrospective study was accepted by the institutional ethics committee. From January 2013 to March 2014, 79 hospitalized adult patients with symptomatic APE were included. Inclusion criteria were a CT pulmonary angiography positive for pulmonary embolism, availability of patient records, and a follow-up of at least 30 days. A review of patient records and images was performed. The maximum diameters of the heart chambers were measured on a reconstructed four-chamber heart view, and the vascular obstruction index was calculated on CT pulmonary angiography. There were statistically significant relationships in both the RA/RV diameter ratio and the RV/left ventricle (LV) diameter ratio between patients with and without adverse outcomes (prights reserved.

  18. Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography.

    Science.gov (United States)

    Caro-Domínguez, Pablo; Compton, Gregory; Humpl, Tilman; Manson, David E

    2016-09-01

    The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children.

  19. Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography

    International Nuclear Information System (INIS)

    Caro-Dominguez, Pablo; Manson, David E.; Compton, Gregory; Humpl, Tilman

    2016-01-01

    The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children. (orig.)

  20. Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Caro-Dominguez, Pablo; Manson, David E. [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada); Compton, Gregory [University of Toronto, Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada); Epworth Hospital, Epworth Medical Imaging, Richmond, VIC (Australia); Humpl, Tilman [University of Toronto, Division of Cardiology, Department of Pediatrics, The Hospital for Sick Children, Toronto, ON (Canada)

    2016-09-15

    The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children. (orig.)

  1. A phantom study on the effect of target diameter and target-to-background ratio on the measurement of SUVmax in PET

    International Nuclear Information System (INIS)

    Cui Yan; Chen Song; Li Yaming

    2013-01-01

    Objective: To investigate the effect of target diameter and target-to-background ratio (TBR) on the measurement of SUV max [| (true SUV-SUV max )/true SUV | × 100%, △SUV max ) in PET. Methods: Six cylinders with various diameters from 5 to 29 mm were inserted in National Electrical Manufacturers Association (NEMA) NU 2-1994 phantom. The six cylinders and background of phantom were filled with 18 F-FDG solution. Six different TBRs (1.79, 3.70, 6.25, 10.59, 14.87 and 17.88) were obtained by changing the 18 F-FDG concentration in the six cylinders. The PET data were acquired in the 2D mode, and the target's inner diameter and SUV max were measured. The logarithmic fitting curves of △SUV max with diameter in different TBRs using equations (y=aln(x)+b) were acquired by Microsoft excel, |a| as the influence power of diameter on △SUV max . Statistical analysis was performed with Pearson correlation test and curve estimation utilizing SPSS 17.0. Results: The Pearson correlation coefficient between △SUV max and diameter was-0.806 (P<0.01). △SUV max was inversely correlated with the diameter. When the diameter (the inner diameter measured on PET images) was 4.0 mm, △SUV max could be as high as 79.73% with different TBRs. The Pearson correlation coefficient between the influence power of diameter on △SUV max (|a|) and TBRs was 0.848 (P<0.05).When TBR was 6.25, 10.59 and 14.87, the corresponding |a| was similar: 38.019, 39.998 and 39.362, respectively. When TBR was 17.88, |a| was the highest as 43.234. When TBR was 1.79 and 3.70, |a| was much smaller: 14.141 and 23.411 respectively. Conclusions: The lesion diameter is inversely correlated with △SUV max . The influence power of diameter on △SUV max is strongly correlated with TBR. Therefore, the effect of target diameter and TBR on the measurement of SUV max should be taken into consideration for follow-up studies. (authors)

  2. Experimental analysis of heat conduction in a high diameter ratio annular gap filled with a rarefied gas

    International Nuclear Information System (INIS)

    Chalabi, H; Lorenzini, M; Morini, G L; Saraceno, L; Boccardi, G; Celata, G P

    2012-01-01

    A first experimental attempt has been realized in order to measure the heat transfer between a heated platinum wire having a diameter (d) of 0.15 mm, disposed along the axis of a cylindrical shell in stainless steel having an inner diameter (D) of 100 mm, and air from atmospheric conditions down to 10 −3 mbar. Temperature differences between the wire and the external stainless steel cylindrical shell in the range of 50–125 K were imposed and the heat power transferred from the wire to the surround was measured as a function of the gas pressure. The experimental results demonstrates that for an accurate measurement of the heat conduction when the pressure goes down to 0.05 mbar is very important to be able to quantify accurately the radiative contribution which becomes predominant at low pressure. The main limitations of the test rig described in this paper have been analysed in order to highlight the modifications which can be suggested to obtain experimental results comparable with theoretical models.

  3. Morphometric analysis of the diameter and g-ratio of the myelinated nerve fibers of the human sciatic nerve during the aging process.

    Science.gov (United States)

    Ugrenović, Sladjana; Jovanović, Ivan; Vasović, Ljiljana; Kundalić, Braca; Čukuranović, Rade; Stefanović, Vladisav

    2016-06-01

    Myelinated nerve fibers suffer from different degrees of atrophy with age. The success of subsequent regeneration varies. The aim of this research was to analyze myelinated fibers of the human sciatic nerve during the aging process. Morphometric analysis was performed on 17 cases with an age range from 9 to 93 years. The outer and inner diameter of 100 randomly selected nerve fibers was measured in each of the cases evaluated, and the g-ratio (axonal diameter/outer diameter of the whole nerve fiber) of each was calculated. Scatter plots of the diameters and g-ratios of the analyzed fibers were then analyzed. Nerve fibers of each case were classified into three groups according to the g-ratio values: group I (g-ratio lower than 0.6), group II (g-ratio from 0.6 to 0.7) and group III (g-ratio higher than 0.7). Afterwards, nerve fibers of group II were further classified into small and large subgroups. The percentages of each group of nerve fibers were computed for each case and these values were used for correlational and bivariate linear regression analysis. The percentage of myelinated nerve fibers with large diameter and optimal g-ratio of the sciatic nerve declines significantly with age. This is accompanied by a simultaneous significant increase in the percentage of small myelinated fibers with g-ratio values close to 1 that occupy the upper left quadrant of the scatter plot. It can be concluded that aging of the sciatic nerve is associated with significant atrophy of large myelinated fibers. Additionally, a significant increase in regenerated nerve fibers with thinner myelin sheath is observed with age, which, together with the large myelinated fiber atrophy, might be the cause of the age-related decline in conduction velocity. A better understanding of the changes in aging peripheral nerves might improve interpretation of their pathological changes, as well as comprehension of their regeneration in individuals of different age.

  4. A novel nitrite biosensor based on the direct electron transfer hemoglobin immobilized in the WO3 nanowires with high length–diameter ratio

    International Nuclear Information System (INIS)

    Liu, Hui; Duan, Congyue; Yang, Chenhui; Chen, Xianjin; Shen, Wanqiu; Zhu, Zhenfeng

    2015-01-01

    WO 3 nanowires (WO 3 NWs) with high length–diameter ratio have been synthesized through a simple synthetic route without any additive and then used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of WO 3 NWs were characterized by scanning electron microscopy, transmission electronic microscopy and X-ray diffraction. Spectroscopic and electrochemical results revealed that WO 3 NWs are an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. Meanwhile, due to unique morphology and property of the WO 3 nanowires, the direct electron transfer of Hb is facilitated and the prepared biosensors displayed good performance for the detection of nitrite with a wide linear range of 1 to 4200 μM, as well as an extremely low detection limit of 0.28 μM. The WO 3 nanowires with high length–diameter ratio could be a promising matrix for the fabrication of mediator-free biosensors, and may find wide potential applications in environmental analysis and biomedical detection. - Highlights: • The WO 3 NWs with high length–diameter ratio have been synthesized. • The WO 3 NWs were used to immobilize Hb to fabricate a mediator-free biosensor. • The biosensor displays a wide linear range of 1–4200 μM for nitrite. • The biosensor exhibits an extremely low detection limit of 0.28 μM for nitrite

  5. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

    International Nuclear Information System (INIS)

    Yang, Jian; Wu, Jiangquan; Zhou, Lang; Wang, Qiuwang

    2016-01-01

    Highlights: • Flow and heat transfer in composite packed beds with low d_t/d_p_e are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it is also

  6. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jian, E-mail: yangjian81@mail.xjtu.edu.cn [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Wu, Jiangquan [CSR Research of Electrical Technology and Material Engineering, Zhuzhou, Hunan 412001 (China); Zhou, Lang; Wang, Qiuwang [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-04-15

    Highlights: • Flow and heat transfer in composite packed beds with low d{sub t}/d{sub pe} are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it

  7. A novel nitrite biosensor based on the direct electron transfer hemoglobin immobilized in the WO{sub 3} nanowires with high length–diameter ratio

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui, E-mail: liuhui@sust.edu.cn; Duan, Congyue; Yang, Chenhui; Chen, Xianjin; Shen, Wanqiu; Zhu, Zhenfeng

    2015-08-01

    WO{sub 3} nanowires (WO{sub 3}NWs) with high length–diameter ratio have been synthesized through a simple synthetic route without any additive and then used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of WO{sub 3}NWs were characterized by scanning electron microscopy, transmission electronic microscopy and X-ray diffraction. Spectroscopic and electrochemical results revealed that WO{sub 3}NWs are an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. Meanwhile, due to unique morphology and property of the WO{sub 3} nanowires, the direct electron transfer of Hb is facilitated and the prepared biosensors displayed good performance for the detection of nitrite with a wide linear range of 1 to 4200 μM, as well as an extremely low detection limit of 0.28 μM. The WO{sub 3} nanowires with high length–diameter ratio could be a promising matrix for the fabrication of mediator-free biosensors, and may find wide potential applications in environmental analysis and biomedical detection. - Highlights: • The WO{sub 3}NWs with high length–diameter ratio have been synthesized. • The WO{sub 3}NWs were used to immobilize Hb to fabricate a mediator-free biosensor. • The biosensor displays a wide linear range of 1–4200 μM for nitrite. • The biosensor exhibits an extremely low detection limit of 0.28 μM for nitrite.

  8. Experimental analysis of heat transfer between a heated wire and a rarefied gas in an annular gap with high diameter ratio

    International Nuclear Information System (INIS)

    Chalabi, H; Lorenzini, M; Morini, G L; Buchina, O; Valougeorgis, D; Saraceno, L

    2012-01-01

    In this paper a first experimental attempt is performed to measure heat conduction through rarefied air at rest contained between two concentric cylinders. The heat transfer between a heated platinum wire having a diameter (d) of 0.15 mm, disposed along the axis of a cylindrical shell in stainless steel having an inner diameter (D) of 100 mm, and a surrounded rarefied gas has been studied experimentally and numerically. The ratio between the outer and inner diameter of the annular region filled by the gas is large (D/d=667). In the annular region filled with air the pressure was varied by using a vacuum pump from atmospheric value down to 10 −3 mbar. Temperature differences between the wire and the external stainless steel wall in the range 50-125 K were imposed and the heat power transferred from the wire to the surround was measured as a function of the gas pressure starting from air at atmospheric conditions down to 10 −3 mbar. The experimental results obtained in these tests were compared with the numerical results obtained by using the linear and nonlinear Shakhov kinetic models.

  9. Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio

    Directory of Open Access Journals (Sweden)

    Shiyang Li

    2018-04-01

    Full Text Available Packed beds are widely used in catalytic reactors or nuclear reactors. Reducing the pressure drop and improving the heat transfer performance of a packed bed is a common research aim. The dimpled structure has a complex influence on the flow and heat transfer characteristics. In the present study, the flow and heat transfer characteristics in structured packed beds with smooth or dimpled spheres are numerically investigated, where two different low channel to particle diameter ratios (N = 1.00 and N = 1.15 are considered. The pressure drop and the Nusselt number are obtained. The results show that, for N = 1.00, compared with the structured packed bed with smooth spheres, the structured packed bed with dimpled spheres has a lower pressure drop and little higher Nusselt number at 1500 < ReH < 14,000, exhibiting an improved overall heat transfer performance. However, for N = 1.15, the structured packed bed with dimpled spheres shows a much higher pressure drop, which dominantly affects the overall heat transfer performance, causing it to be weaker. Comparing the different channel to particle diameter ratios, we find that different configurations can result in: (i completely different drag reduction effect; and (ii relatively less influence on heat transfer enhancement.

  10. Thermal hydraulic analyses of accidents associated with coolant leak from the primary circuit through a hole 10 mm equivalent diameter for the needs of PTS

    International Nuclear Information System (INIS)

    Krhounkova, J.; Kral, P.; Parduba, Z.

    1999-10-01

    The conservative assumptions of the analyses were oriented towards a worsening of the process with respect to the pressurized thermal shock (PTS). Four variants were treated, viz. leaks from the cold or hot leg, each at the rated power or zero power. Since the temperature of water supplied to the primary circuit by the emergency core cooling system is an important parameter with respect to a PTS, the calculations were performed by the iterative procedure: the basic thermal hydraulic calculation was performed by the RELAP5/MOD3.2.1 code which calculates the behaviour of the primary and secondary circuits, whereas the MELCOR code was used to calculate the behaviour of the parameters in the hermetic rooms. The calculation by the RELAP code was then repeated using data from the MELCOR calculations. Interventions by the reactor operators were also considered. (P.A.)

  11. Flow patterns and hydraulic losses in quasi-coil pipes : The effects of configuration of bend cross section, curvature ratio and bend angle

    OpenAIRE

    Shimizu, Yukimaru; Sugino, Koichi; Yasui, Masaji; Hayakawa, Yukitaka; Kuzuhara, Sadao

    1985-01-01

    Pipes with bend combinations are much used in the heat exchangers, since the curved path in the bends promotes the mixing in flow for active heat transfer. In the present paper, one of the pipes with bend combinations, namely, quasi-coiled pipes composed of many bend elements are investigated, and the relationships between the hydraulic loss and the secondary flow are studied experimentally. The configurations of the cross sections, the bent angles and the curvature ratios of the bend element...

  12. Reference interval for the disc-macula distance to disc diameter ratio in a large population of healthy Japanese adults: A prospective, observational study.

    Science.gov (United States)

    Sato, Ken-Ichi

    2017-04-01

    This study presents the calculated reference interval for the disc-to-macula distance to disc diameter ratio (DM:DD) based on a large population of healthy Japanese adults.A total of 308 consecutive, healthy Japanese adults were examined in this prospective observational study. Eighteen subjects were also excluded because of poor quality of the fundus photograph of one or both eyes; 290 (161 men and 129 women) were included in this study. For each subject, a color fundus photograph of one eye, either the right or left, was randomly selected and used for analysis. On the photograph, the distances between the fovea and the nearest temporal margin of the optic disc (Dft), and the two kinds of disc diameters (D1 and D2), which bisected at right angles and one of which was directed to the fovea (D1), were measured. DM:DD was estimated using the formula: (2Dft + D1)/(D1 + D2).The mean ± standard deviation of DM:DD was 2.91 ± 0.49 for men and 2.96 ± 0.54 for women; there was no sex difference (P = .78, Mann-Whitney U test). Also, almost no relationship was found between DM:DD and age (ρ = -.12, P = .04, Spearman's rank correlation coefficient). The data did not fit a normal distribution (P < .001, Kolmogorov-Smirnov test). The estimated reference interval for DM:DD corresponding to the 2.5th and 97.5th percentiles was 2.12 to 4.18.Using a nonparametric approach, the reference interval for DM:DD of a large population of healthy Japanese adults was calculated to be 2.12 to 4.18, regardless of age or sex.

  13. Correlation between cup-to-disc ratio and cup/retrobulbar optic nerve diameter proportion assessed by high-resolution ultrasound in glaucomatous eyes

    Directory of Open Access Journals (Sweden)

    Wilian Silva Queiroz

    2013-10-01

    Full Text Available PURPOSE: To investigate the correlation between the measurements of the cup/retrobulbar optic nerve diameter (C/OND proportion obtained by high-resolution 20-MHz B-mode ultrasound (US and those of the cup/disc ratio (C/D obtained by fundus biomicroscopy (BIO and optical coherence tomography (OCT. METHODS: Thirty eyes of 15 glaucomatous patients with any C/D proportion were studied. All patients underwent examination of the vertical C/D by BIO with a 78D lens and time-domain OCT analysis, as well as the vertical C/OND proportion using 20-MHz US measurements. All data were analyzed by correlation and agreement tests. RESULTS: The Spearman test showed a strong correlation between C/D results obtained by BIO and the measurements of C/OND (US (r=0.788, p<0.0001, and with C/D obtained by OCT (r=0.8529, p<0.0001. However, comparison of C/D results obtained with OCT to those obtained by with C/OND (US showed only a moderate correlation (r=0.6727, p<0.0001. Bland-Altman analysis did not show good agreement between C/D (BIO and C/OND (US. CONCLUSIONS: The results demonstrate that B-mode ultrasound examination with a 20 MHz probe can be a good additional method for the evaluation of the C/D ratio in glaucomatous patients, and may be considered as an alternative gross tool in glaucomatous patients with optic media opacities.

  14. Association of body mass index, sagittal abdominal diameter and waist-hip ratio with cardiometabolic risk factors and adipocytokines in Arab children and adolescents

    Directory of Open Access Journals (Sweden)

    Al-Attas Omar S

    2012-08-01

    Full Text Available Abstract Background Sagittal abdominal diameter (SAD is a novel anthropometric measure hypothesized to be a surrogate measure of visceral abdominal obesity in adults. This study aims to determine whether SAD is superior to other anthropometric measures such as body mass index (BMI and waist to hip ratio (WHR in terms of association to cardiometabolic risk and circulating adipocytokine concentrations in a cohort of Saudi children and adolescents. Methods A total of 948 (495 boys and 453 girls apparently healthy children with varying BMI, aged 10–17 years, were included in this cross sectional study. Fasting glucose, lipid profile, leptin, adiponectin, resistin, insulin, TNF-α and aPAI-1 were measured in serum and HOMA-IR was calculated. MetS components were defined according to the International Diabetes Federation (IDF criteria. Results BMI was superior to SAD as well as WHR, and had the highest number of significant associations to MetS components and adipocytokines even after adjustment for age and gender, including blood pressure, lipids, glucose and leptin. Conclusion In conclusion, while SAD is significantly associated with components of MetS among children and adolescents, it is not superior to BMI. The use of SAD therefore may not be practical for use in the pediatric clinical setting. Follow-up studies are needed to determine whether SAD has clinical significance in terms of harder outcomes such as predicting diabetes mellitus or cardiovascular diseases.

  15. Changes of Root Hydraulic Conductivity and Root/Shoot Ratio of Durum Wheat and Barley in Relation to Nitrogen Availability and Mercury Exposure

    Directory of Open Access Journals (Sweden)

    Giovanna Angelino

    2011-02-01

    Full Text Available The aim of this research was to verify, on whole plant level and during all the plant cycle, the hypothesis that nitrogen deficiency reduces root hydraulic conductivity through the water channels (aquaporins activity, and that the plant reacts by changing root/shoot ratio. Root hydraulic conductivity, plant growth, root/shoot ratio and plant water status were assessed for durum wheat (Triticum durum Desf. and barley (Hordeum vulgare L., as influenced by nitrogen availability and HgCl2 treatment. On both species during the plant cycle, nitrogen deficiency induced lower root hydraulic conductivity (-49 and -66% respectively for barley and wheat and lower plant growth. On wheat was also observed cycle delay, lower plant nitrogen content, but not lower leaf turgor pressure and epidermic cell dimension. The lower plant growth was due to lower plant dimension and lower tillering. Root /shoot ratio was always higher for nitrogen stressed plants, whether on dry matter or on surface basis. This was due to lower effect of nitrogen stress on root growth than on shoot growth. On wheat HgCl2 treatment determined lower plant growth, and more than nitrogen stress, cycle delay and higher root/shoot ratio. The mercury, also, induced leaf rolling, lower turgor pressure, lower NAR, higher root cell wall lignification and lower epidermic cell number per surface unity. In nitrogen fertilized plants root hydraulic conductivity was always reduced by HgCl2 treatment (-61 and 38%, respectively for wheat and barley, but in nitrogen unfertilized plants this effect was observed only during the first plant stages. This effect was higher during shooting and caryopsis formation, lower during tillering. It is concluded that barley and durum wheat react to nitrogen deficiency and HgCl2 treatment by increasing the root/shoot ratio, to compensate water stress due to lower water root conductivity probably induced by lower aquaporin synthesis or inactivation. However, this

  16. Changes of Root Hydraulic Conductivity and Root/Shoot Ratio of Durum Wheat and Barley in Relation to Nitrogen Availability and Mercury Exposure

    Directory of Open Access Journals (Sweden)

    Celestino Ruggiero

    2007-09-01

    Full Text Available The aim of this research was to verify, on whole plant level and during all the plant cycle, the hypothesis that nitrogen deficiency reduces root hydraulic conductivity through the water channels (aquaporins activity, and that the plant reacts by changing root/shoot ratio. Root hydraulic conductivity, plant growth, root/shoot ratio and plant water status were assessed for durum wheat (Triticum durum Desf. and barley (Hordeum vulgare L., as influenced by nitrogen availability and HgCl2 treatment. On both species during the plant cycle, nitrogen deficiency induced lower root hydraulic conductivity (-49 and -66% respectively for barley and wheat and lower plant growth. On wheat was also observed cycle delay, lower plant nitrogen content, but not lower leaf turgor pressure and epidermic cell dimension. The lower plant growth was due to lower plant dimension and lower tillering. Root /shoot ratio was always higher for nitrogen stressed plants, whether on dry matter or on surface basis. This was due to lower effect of nitrogen stress on root growth than on shoot growth. On wheat HgCl2 treatment determined lower plant growth, and more than nitrogen stress, cycle delay and higher root/shoot ratio. The mercury, also, induced leaf rolling, lower turgor pressure, lower NAR, higher root cell wall lignification and lower epidermic cell number per surface unity. In nitrogen fertilized plants root hydraulic conductivity was always reduced by HgCl2 treatment (-61 and 38%, respectively for wheat and barley, but in nitrogen unfertilized plants this effect was observed only during the first plant stages. This effect was higher during shooting and caryopsis formation, lower during tillering. It is concluded that barley and durum wheat react to nitrogen deficiency and HgCl2 treatment by increasing the root/shoot ratio, to compensate water stress due to lower water root conductivity probably induced by lower aquaporin synthesis or inactivation. However, this

  17. The study of the influence of the diameter ratio and blade number to the performance of the cross flow wind turbine by using 2D computational fluid dynamics modeling

    Science.gov (United States)

    Tjahjana, Dominicus Danardono Dwi Prija; Purbaningrum, Pradityasari; Hadi, Syamsul; Wicaksono, Yoga Arob; Adiputra, Dimas

    2018-02-01

    Cross flow turbine can be one of the alternative energies for regions with low wind speed. Collision between wind and the blades which happened two times caused the cross flow turbine to have high power coefficient. Some factors that influence the turbine power coefficient are diameter ratio and blade number. The objective of the research was to study the effect of the diameter ratio and the blade number to the cross flow wind turbine performance. The study was done in two dimensional (2D) computational fluid dynamics (CFD) simulation method using the ANSYS-Fluent software. The turbine diameter ratio were 0.58, 0.63, 0.68 and 0.73. The diameter ratio resulting in the highest power coefficient value was then simulated by varying the number of blades, namely 16, 20 and 24. Each variation was tested on the wind speed of 2 m/s and at the tip speed ratio (TSR) of 0.1 to 0.4 with the interval of 0.1. The wind turbine with the ratio diameter of 0.68 and the number of blades of 20 generated the highest power coefficient of 0.5 at the TSR of 0.3.

  18. Structure of nitrogen-converting communities induced by hydraulic retention time and COD/N ratio in constantly aerated granular sludge reactors treating digester supernatant.

    Science.gov (United States)

    Cydzik-Kwiatkowska, Agnieszka; Rusanowska, Paulina; Zielińska, Magdalena; Bernat, Katarzyna; Wojnowska-Baryła, Irena

    2014-02-01

    This study investigated how hydraulic retention time (HRT) and COD/N ratio affect nitrogen-converting consortia in constantly aerated granules treating high-ammonium digester supernatant. Three HRTs (10, 13, 19 h) were tested at COD/N ratios of 4.5 and 2.3. Denaturing gradient gel electrophoresis and relative real-time PCR were used to characterize the microbial communities. When changes in HRT and COD/N increased nitrogen loading, the ratio of the relative abundance of aerobic to anaerobic ammonium-oxidizers decreased. The COD/N ratio determined the species composition of the denitrifiers; however, Thiobacillus denitrificans, Pseudomonas denitrificans and Azoarcus sp. showed a high tolerance to the environmental conditions and occurred in the granules from all reactors. Denitrifier genera that support granule formation were identified, such as Pseudomonas, Shinella, and Flavobacterium. In aerated granules, nirK-possessing bacteria were more diverse than nirS-possessing bacteria. At a low COD/N ratio, N2O-reducer diversity increased because of the presence of bacteria known as aerobic denitrifiers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Morphology and Hydraulic Architecture of Vitis vinifera L. cv. Syrah and Torrontés Riojano Plants Are Unaffected by Variations in Red to Far-Red Ratio.

    Directory of Open Access Journals (Sweden)

    Carina Verónica González

    Full Text Available Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1, whereas overhead or lateral low R:FR (below 1.1 are sensed in the presence of plant shade or neighboring plants, respectively. Grapevine is one of the most important fruit crops in the world. To date, studies on grapevine response to light focused on different Photosynthetic Active Radiation (PAR levels; however, limited data exist about its response to light quality. In this study we aimed to investigate morphological, biochemical, and hydraulic responses of Vitis vinifera to variations in R:FR. Therefore, we irradiated Syrah and Torrontés Riojano plants, grown in a glasshouse, with lateral FR light (low lateral R:FR treatment, while others, that were kept as controls, were not irradiated (ambient lateral R:FR treatment. In response to the low lateral R:FR treatment, grapevine plants did not display any of the SAS morphological markers (i.e. stem length, petiole length and angle, number of lateral shoots in any of the cultivars assessed, despite an increase in gibberelins and auxin concentrations in leaf tissues. Low lateral R:FR did not affect dry matter partitioning, water-related traits (stomata density and index, wood anatomy, or water-related physiology (plant conductance, transpiration rate, stem hydraulic conductivity, stomatal conductance. None of the Vitis vinifera varieties assessed displayed the classical morphological and hydraulic responses associated to SAS induced by phytochromes. We discuss these results in the context of natural grapevine environment and

  20. Changes in Cross-Sectional Area and Transverse Diameter of the Heart on Inspiratory and Expiratory Chest CT: Correlation with Changes in Lung Size and Influence on Cardiothoracic Ratio Measurement.

    Directory of Open Access Journals (Sweden)

    Hayato Tomita

    Full Text Available The aim of this study was to investigate physiological changes in cardiac area and diameters between inspiratory and expiratory chest computed tomography (CT, and to assess their correlation with lung size change and influence on cardiothoracic ratio (CTR measurements.The institutional review board of our institution approved this study, and informed consent was waived. Forty-three subjects underwent inspiratory and expiratory chest CT as part of routine clinical care. On both inspiratory and expiratory scans, lung volumes and maximum lung diameters (transverse and vertical directions were measured. The maximum cardiac cross-sectional area (CSA and the maximum transverse cardiac diameter were measured on both scans, and the CT-based CTR was calculated. Changes in the lung and cardiac measurements were expressed as the expiratory/inspiratory (E/I ratios. Comparisons between inspiratory and expiratory measurements were made by the Wilcoxon signed-rank test. Correlations between the E/I ratios of lung and heart measurements were evaluated by Spearman's rank correlation analysis.Cardiac CSA and transverse cardiac diameter was significantly larger on expiratory than on inspiratory CT (p < 0.0001. Significant negative correlations were found between the E/I ratios of these cardiac measurements and the E/I ratios of lung volume and vertical lung diameter (p < 0.01. CT-based CTR was significantly larger on expiration than on inspiration (p < 0.0001.Heart size on chest CT depends on the phase of ventilation, and is correlated with changes in lung volume and craniocaudal lung diameter. The CTR is also significantly influenced by ventilation.

  1. 内外径比值对横向效应侵彻体的影响分析%Simulation Analysis of the Influence of Length-Diameter Ratio on Lateral Effect

    Institute of Scientific and Technical Information of China (English)

    焦志刚; 曹旭; 张明博

    2017-01-01

    通过研究不同内外径比值对PELE横向效应的影响,对不同内外径比情况弹丸侵彻靶板的过程进行数值仿真.结果表明:任意一种类型横向效应侵彻体,其消耗的能量随着内外径比值的增大而增大;对于一个设定的内外径比,总有一个最佳长径比值使其横向效应效果最优.%Through the study of the influence of different ratio of inner and outer diameters on the transverse effect of PELE,numerical simulation of projectile penetration into target plate with different ratio of internal and external diameter was carried out.The results show that:for any type of lateral effect penetrator,its energy consumption increases as the diameter ratio increases;for a set diameter ratio,there is always an optimum value so that the lateral effect will be best.

  2. Performance of a haloalkaliphilic bioreactor and bacterial community shifts under different COD/SO{sub 4}{sup 2−} ratios and hydraulic retention times

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jie-Min [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Song, Zi-Yu [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Yan, Dao-Jiang; Liu, Yi-Lan [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Mao-Hua [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Cao, Hong-Bin [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China); Xing, Jian-Min, E-mail: jmxing@home.ipe.ac.cn [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, PO Box 353, Beijing 100190 (China)

    2014-06-01

    Highlights: • Haloalkaliphilic microorganisms were used to reduce sulfate. • Sulfide concentration reached up to 1603 mg/L. • There was no sulfide inhibition to haloalkaliphilic microorganisms. • Bacterial community of haloalkaliphilic bioreactor was studied. - Abstract: Sulfur dioxide from flue gas was converted into sulfate after the absorption of alkaline solutions. Haloalkaliphilic microorganisms have been used in reducing sulfate to decrease expenses and avoid sulfide inhibition. The effects of different COD/SO{sub 4}{sup 2−} ratios and hydraulic retention times (HRTs) on the sulfate removal efficiency and bacterial community were investigated in model experiments. Ethanol showed better performance as an electron donor than lactate. The optimum COD/SO{sub 4}{sup 2−} ratio and HRT were 4.0 and 18 h, respectively, with respective sulfate removal efficiency and rate of 97.8 ± 1.11% and 6.26 ± 0.0710 g/L d. Sulfide concentrations reached 1603 ± 3.38 mg/L. Based on denaturing gradient gel electrophoresis analysis of 16S rDNA, the major sulfate-reducing bacterium (SRB) was Desulfonatronovibrio sp., which was only detected at a COD/SO{sub 4}{sup 2−} ratio of 4.0 using ethanol as an electron donor. Different HRTs had no significant effect on the band corresponding to this species. PCR results show that methane-producing archaea (MPA) were from the acetoclastic methanogenic family Methanosarcinaceae. Quantitative real-time PCR did not demonstrate any significant competition between SRB and MPA. The findings of this study indicate that sulfate reduction, nitrate reduction, and sulfide oxidization may occur in the same bioreactor.

  3. Distribution of sulfonamides in liquid and solid anaerobic digestates: effects of hydraulic retention time and swine manure to rice straw ratio.

    Science.gov (United States)

    Jin, Hongmei; Xu, Caiyun; Du, Jing; Wu, Huashan; Huang, Hongying; Chang, Zhizhou; Xu, Yueding; Zhou, Lixiang

    2017-02-01

    The effects of hydraulic retention time (20 and 15 days) and swine manure to rice straw ratios on distribution of sulfonamides (SAs) in liquid and solid anaerobic digestates were studied using bench-scale completely stirred tank reactors at (37 ± 1) °C. Results showed that anaerobic digestion (AD) treatment exhibited a good removal effect on sulfadiazine (SDZ), sulfadimidine (SM2) and sulfachloropyridazine (SCP), especially at HRT = 20 days and co-digestion with swine manure and rice straw. The removal rates of SDZ and SM2 were more than 90%, but only 72.8% for SCP. The residual SAs were mainly remained in solid digestates, with residual rates ranging from 28.8% to 71.3%, 40.6% to 88.0, and 82.7% to 97.0% for SDZ, SM2 and SCP, respectively. Due to lower pKa and higher log K ow of SCP, its residue in solid digestates was far more than SDZ and SM2. Higher HRT and co-digestion could improve the degradation of SAs, which can also be put down to the occurrence of cometabolism of SAs and COD.

  4. Analysis of in-R12 CHF data: influence of hydraulic diameter and heating length; test of Weisman boiling crisis model; Analyse de donnees de flux critique en R12: influence du diametre hydraulique et de la longueur chauffante; test du modele de Weisman

    Energy Technology Data Exchange (ETDEWEB)

    Czop, V; Herer, C; Souyri, A; Garnier, J

    1993-09-01

    In order to progress on the comprehensive modelling of the boiling crisis phenomenon, Electricite de France (EDF), Commissariat a l`Energie Atomique (CEA) and FRAMATOME have set up experimental programs involving in-R12 tests: the EDF APHRODITE program and the CEA-EDF-FRAMATOME DEBORA program. The first phase in these programs aims to acquire critical heat flux (CHF) data banks, within large thermal-hydraulic parameter ranges, both in cylindrical and annular configurations, and with different hydraulic diameters and heating lengths. Actually, three data banks have been considered in the analysis, all of them concerning in-R12 round tube tests: - the APHRODITE data bank, obtained at EDF with a 13 mn inside diameter, - the DEBORA data bank, obtained at CEA with a 19.2 mm inside diameter, - the KRISTA data bank, obtained at KfK with a 8 mm inside diameter. The analysis was conducted using CHF correlations and with the help of an advanced mathematical tool using pseudo-cubic thin plate type Spline functions. Two conclusions were drawn: -no influence of the heating length on our CHF results, - the influence of the diameter on the CHF cannot be simply expressed by an exponential function of this parameter, as thermal-hydraulic parameters also have an influence. Some calculations with Weisman and Pei theoretical boiling crisis model have been compared to experimental values: fairly good agreement was obtained, but further study must focus on improving the modelling of the influence of pressure and mass velocity. (authors). 12 figs., 4 tabs., 21 refs.

  5. Effect of mixture ratio, solids concentration and hydraulic retention time on the anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Fongsatitkul, Prayoon; Elefsiniotis, Panagiotis; Wareham, David G

    2010-09-01

    This paper describes how the degradation of the organic fraction of municipal solid waste (OFMSW) is affected through codigestion with varying amounts of return activated sludge (RAS). Solid waste that had its inorganic fraction selectively removed was mixed with RAS in ratios of 100% OFMSW, 50% OFMSW/50% RAS, and 25% OFMSW/75% RAS. The total solids (TS) concentration was held at 8% and three anaerobic digester systems treating the mixtures were held (for the first run) at a total hydraulic retention time (HRT) of 28 days. Increasing amounts of RAS did not however improve the mixture's digestability, as indicated by little change and/or a drop in the main performance indices [including percentage volatile solids (VS) removal and specific gas production]. The optimum ratio in this research therefore appeared to be 100% OFMSW with an associated 85.1 ± 0.6% VS removal and 0.72 ± 0.01 L total gas g(- 1) VS. In the second run, the effect of increasing percentage of TS (8, 12% and 15%) at a system HRT of 28 days was observed to yield no improvement in the main performance indices (i.e. percentage VS removal and specific gas production). Finally, during the third run, variations in the total system HRT were investigated at an 8% TS, again using 100% OFMSW. Of the HRTs explored (23, 28 and 33 days), the longest HRT yielded the best performance overall, particularly in terms of specific gas production (0.77 ± 0.01 L total gas g(-1) VS).

  6. Evaluation of the Hydraulic Performance and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-Cm Diameter Centrifugal Contactor

    International Nuclear Information System (INIS)

    Law, J.D.; Tillotson, R.D.; Todd, T.A.

    2002-01-01

    The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A's 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design of

  7. Co-existence of COPD and bronchiectasis: a risk factor for a high ratio of main pulmonary artery to aorta diameter (PA:A from computed tomography in COPD patients

    Directory of Open Access Journals (Sweden)

    Dou S

    2018-02-01

    Full Text Available Shuang Dou,1 Chunyan Zheng,1 Xiuli Ji,2 Wei Wang,1 Mengshuang Xie,1 Liwei Cui,1 Wei Xiao1 1Department of Pulmonary Medicine, Qilu Hospital, Shandong University, Jinan, People’s Republic of China; 2Department of Pulmonary Disease, Jinan Traditional Chinese Medicine Hospital, Jinan, People’s Republic of China Background: Pulmonary vascular disease, especially pulmonary hypertension, is an important complication of COPD. Bronchiectasis is considered not only a comorbidity of COPD, but also a risk factor for vascular diseases. The main pulmonary artery to aorta diameter ratio (PA:A ratio has been found to be a reliable indicator of pulmonary vascular disease. It is hypothesized that the co-existence of COPD and bronchiectasis may be associated with relative pulmonary artery enlargement (PA:A ratio >1.Methods: This retrospective study enrolled COPD patients from 2012 through 2016. Demographic and clinical data were collected. Bhalla score was used to determine the severity of bronchiectasis. Patient characteristics were analyzed in two ways: the high (PA:A >1 and low (PA:A ≤1 ratio groups; and COPD with and without bronchiectasis groups. Logistic regression analysis was used to assess risk factors for high PA:A ratios.Results: In this study, 480 COPD patients were included, of whom 168 had radiographic bronchiectasis. Patients with pulmonary artery enlargement presented with poorer nutrition (albumin, 35.6±5.1 vs 38.3±4.9, P<0.001, lower oxygen partial pressure (74.4±34.5 vs 81.3±25.4, P<0.001, more severe airflow obstruction (FEV1.0, 0.9±0.5 vs 1.1±0.6, P=0.004, and a higher frequency of bronchiectasis (60% vs 28.8%, P<0.001 than patients in the low ratio group. Patients with both COPD and bronchiectasis had higher levels of systemic inflammation (erythrocyte sedimentation rate, P<0.001 and fibrinogen, P=0.006 and PA:A ratios (P<0.001. A higher PA:A ratio was significantly closely correlated with a higher Bhalla score (r=0.412, P<0

  8. Preliminary study of the thermo-hydraulic behaviour of the binary breeder reactor

    International Nuclear Information System (INIS)

    Silveira Luz, M. da; Ferreira, W.J.

    1984-06-01

    Continuing the development of the Binary Breeder Reactor, its physical configuration and the advantages of differents types of spacers are analysed. In order to simulate the thermo-hydraulic behaviour and obtain data for a preliminary evaluation of the core geometry, the COBRA III C code was used to study the effects of the lenght and diameter of the fuel element, the coolant inlet temperature, the system pressure, helicoidal pitch and the pitch to diameter ratio. (Author) [pt

  9. Hydraulic structures

    CERN Document Server

    Chen, Sheng-Hong

    2015-01-01

    This book discusses in detail the planning, design, construction and management of hydraulic structures, covering dams, spillways, tunnels, cut slopes, sluices, water intake and measuring works, ship locks and lifts, as well as fish ways. Particular attention is paid to considerations concerning the environment, hydrology, geology and materials etc. in the planning and design of hydraulic projects. It also considers the type selection, profile configuration, stress/stability calibration and engineering countermeasures, flood releasing arrangements and scouring protection, operation and maintenance etc. for a variety of specific hydraulic structures. The book is primarily intended for engineers, undergraduate and graduate students in the field of civil and hydraulic engineering who are faced with the challenges of extending our understanding of hydraulic structures ranging from traditional to groundbreaking, as well as designing, constructing and managing safe, durable hydraulic structures that are economical ...

  10. Hydraulic turbines

    International Nuclear Information System (INIS)

    Meluk O, G.

    1998-01-01

    The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation

  11. Basic hydraulics

    CERN Document Server

    Smith, P D

    1982-01-01

    BASIC Hydraulics aims to help students both to become proficient in the BASIC programming language by actually using the language in an important field of engineering and to use computing as a means of mastering the subject of hydraulics. The book begins with a summary of the technique of computing in BASIC together with comments and listing of the main commands and statements. Subsequent chapters introduce the fundamental concepts and appropriate governing equations. Topics covered include principles of fluid mechanics; flow in pipes, pipe networks and open channels; hydraulic machinery;

  12. Linking plant hydraulics and beta diversity in tropical forests

    Energy Technology Data Exchange (ETDEWEB)

    Christoffersen, Bradley [Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Meir, Patrick [School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE UK; Research School of Biology, Australian National University, Canberra ACT 2601 Australia; McDowell, Nate G. [Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-05-31

    In tropical forests, studies of xylem traits governing water transport through plants, or ‘hydraulic architecture’ (Tyree et al., 1991), and changes in species composition across environmental gradients, or ‘beta diversity’ (Gentry, 1988; Ackerly & Cornwell, 2007), have progressedmostly in parallel until recently (Hao et al., 2008; Bartlett et al., 2016). In this issue of New Phytologist, Cosme et al. (pp. 000–5 000) present a timely contribution to the intersection of plant hydraulic architecture (HA) with trait-based community ecology. Building on previous biogeographical work that demonstrated shifts in species composition (beta diversity) across a gradient from valleys to plateaus in central Amazonia (Schietti et al., 2014), Cosme et al. explore how variation in HA might underpin this sorting, sampling pairs of congeneric species restrictedmostly to either plateau or valley habitats. Valley species had significantly lower wood density and higher hydraulically-weighted vessel diameter and vessel area. By contrast, trees with some of the largest hydraulically-weighted vessel diameters existed in tall, deciduous plateau species, while the leaf: sapwood area ratio decreased with height in valley but not plateau species. These intriguing results suggest that species differentiation in water transport traits mediate edaphic filtering along the valley-toplateau gradient, in contrast to previous work where wood mechanical support mediated valley-to-plateau environmental filtering (Fortunel et al., 2014).

  13. Hydraulic Structures

    Data.gov (United States)

    Department of Homeland Security — This table is required whenever hydraulic structures are shown in the flood profile. It is also required if levees are shown on the FIRM, channels containing the...

  14. Failure Diameter Resolution Study

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-12-19

    Previously the SURFplus reactive burn model was calibrated for the TATB based explosive PBX 9502. The calibration was based on fitting Pop plot data, the failure diameter and the limiting detonation speed, and curvature effect data for small curvature. The model failure diameter is determined utilizing 2-D simulations of an unconfined rate stick to find the minimum diameter for which a detonation wave propagates. Here we examine the effect of mesh resolution on an unconfined rate stick with a diameter (10mm) slightly greater than the measured failure diameter (8 to 9 mm).

  15. The importance of hydraulic architecture to the distribution patterns of trees in a central Amazonian forest.

    Science.gov (United States)

    Cosme, Luiza H M; Schietti, Juliana; Costa, Flávia R C; Oliveira, Rafael S

    2017-07-01

    Species distributions and assemblage composition may be the result of trait selection through environmental filters. Here, we ask whether filtering of species at the local scale could be attributed to their hydraulic architectural traits, revealing the basis of hydrological microhabitat partitioning in a Central Amazonian forest. We analyzed the hydraulic characteristics at tissue (anatomical traits, wood specific gravity (WSG)), organ (leaf area, specific leaf area (SLA), leaf area : sapwood area ratio) and whole-plant (height) levels for 28 pairs of congeneric species from 14 genera restricted to either valleys or plateaus of a terra-firme forest in Central Amazonia. On plateaus, species had higher WSG, but lower mean vessel area, mean vessel hydraulic diameter, sapwood area and SLA than in valleys; traits commonly associated with hydraulic safety. Mean vessel hydraulic diameter and mean vessel area increased with height for both habitats, but leaf area and leaf area : sapwood area ratio investments with tree height declined in valley vs plateau species. [Correction added after online publication 29 March 2017: the preceding sentence has been reworded.] Two strategies for either efficiency or safety were detected, based on vessel size or allocation to sapwood. In conclusion, contrasting hydrological conditions act as environmental filters, generating differences in species composition at the local scale. This has important implications for the prediction of species distributions under future climate change scenarios. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  16. Hydraulically actuated artificial muscles

    Science.gov (United States)

    Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

    2012-04-01

    Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

  17. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    International Nuclear Information System (INIS)

    Yu, Xin-Guo; Choi, Ki-Yong

    2015-01-01

    between the model and the prototype, a set of scaling criteria for exact hydraulic similarity are developed. Particularly, it is found that the scaling of the pipe inner diameter should be scaled down in relation to that of the pipe length, if the exact hydraulic similarity is preserved for a pipe. In addition, the relative pipe length ratio and the cross-sectional area ratio should be kept same between the model and the prototype. Based on the developed scaling criteria, a full pressure reduced-height model is developed with respect a simple prototype loop proposed. In addition, a full-height model is also made

  18. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xin-Guo; Choi, Ki-Yong [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    between the model and the prototype, a set of scaling criteria for exact hydraulic similarity are developed. Particularly, it is found that the scaling of the pipe inner diameter should be scaled down in relation to that of the pipe length, if the exact hydraulic similarity is preserved for a pipe. In addition, the relative pipe length ratio and the cross-sectional area ratio should be kept same between the model and the prototype. Based on the developed scaling criteria, a full pressure reduced-height model is developed with respect a simple prototype loop proposed. In addition, a full-height model is also made.

  19. Hydraulic manipulator

    International Nuclear Information System (INIS)

    Sinha, A.K.; Srikrishnamurty, G.

    1990-01-01

    Successful operation of nuclear plant is largely dependent on safe handling of radio-active material. In order to reduce this handling problem and minimise the exposure of radiation, various handling equipment and manipulators have been developed according to the requirements. Manufacture of nuclear fuel, which is the most important part of the nuclear industry, involves handling of uranium ingots weighing approximately 250 kg. This paper describes a specially designed hydraulic manipulator for handling of the ingots in a limited space. It was designed to grab and handle the ingots in any position. This has following drive motions: (1)gripping and releasing, (2)lifting and lowering (z-motion), (3)rotation about the horizontal axis (azimuth drive), (4)rotation about the job axis, and (5)rotation about the vertical axis. For horizontal motion (X and Y axis motion) this equipment is mounted on a motorised trolley, so that it can move inside the workshop. For all drives except the rotation about the job axis, hydraulic cylinders have been used with a battery operated power pack. Trolley drive is also given power from same battery. This paper describes the design aspects of this manipulator. (author). 4 figs

  20. Calculation of saturated hydraulic conductivity of bentonite

    International Nuclear Information System (INIS)

    He Jun

    2006-01-01

    Hydraulic conductivity test has some defects such as weak repeatability, time-consuming. Taking bentonite as dual porous media, the calculation formula of the distance, d 2 , between montmorillonite in intraparticle pores is deduced. Improved calculated method of hydraulic conductivity is obtained using d 2 and Poiseuille law. The method is valid through the comparison with results of test and other methods. The method is very convenient to calculate hydraulic conductivity of bentonite of certain montmorillonite content and void ratio. (authors)

  1. Study of the equivalent diameter concept for heat transfer by forced convection in annular channels

    International Nuclear Information System (INIS)

    Mendez T, D.

    1994-01-01

    This work describes a comparative analysis between experimental values of heat transfer coefficients in fully developed turbulent flow for a concentric annular channel, and those calculated with the empirical correlations obtained for tubes by Dittus-Boelter, Sieder and Tate, a modified Colburn equation, and that proposed by Gnielinski which applies the analogy between friction and heat transfer. The coefficients were calculated by means of two different equivalent diameters: 1) The hydraulic equivalent diameter; and 2) The heated equivalent diameter. It was concluded that the hydraulic equivalent diameter gives much better results than the heated equivalent diameter. (Author)

  2. Different hydraulic traits of woody plants from tropical forests with contrasting soil water availability.

    Science.gov (United States)

    Zhu, Shi-Dan; Chen, Ya-Jun; Fu, Pei-Li; Cao, Kun-Fang

    2017-11-01

    In southwestern China, tropical karst forests (KF) and non-karst rain forests (NKF) have different species composition and forest structure owing to contrasting soil water availability, but with a few species that occur in both forests. Plant hydraulic traits are important for understanding the species' distribution patterns in these two forest types, but related studies are rare. In this study, we investigated hydraulic conductivity, vulnerability to drought-induced cavitation and wood anatomy of 23 abundant and typical woody species from a KF and a neighboring NKF, as well as two Bauhinia liana species common to both forests. We found that the KF species tended to have higher sapwood density, smaller vessel diameter, lower specific hydraulic conductivity (ks) and leaf to sapwood area ratio, and were more resistant to cavitation than NKF species. Across the 23 species distinctly occurring in either KF or NKF, there was a significant tradeoff between hydraulic efficiency and safety, which might be an underlying mechanism for distributions of these species across the two forests. Interestingly, by possessing rather large and long vessels, the two Bauhinia liana species had extremely high ks but were also high resistance to cavitation (escaping hydraulic tradeoff). This might be partially due to their distinctly dimorphic vessels, but contribute to their wide occurrence in both forests. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Numerical Study of the Rib Arrangements for Enhancing Heat Transfer in a Two-pass Channel of Large Aspect Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sol; Choi, Seok Min; Sohn, Ho-Seong; Cho, Hyung Hee [Yonsei Univ., Seoul (Korea, Republic of)

    2017-03-15

    The present study investigated the effect of the rib arrangement and a guide vane for enhancing internal cooling of the blade. Two types of rib arrangements were used in the first and second passage in parallel. Aspect ratio of the channel was 5 and a fixed Reynolds number based on hydraulic diameter was 10,000. The attack angle of rib was 60°, rib pitch-to-height ratio (p/e) was 10, and the rib height-to-hydraulic-diameter ratio (e/D{sub n}) was 0.075. The effect of an interaction between Dean vortices and the secondary vortices from the first passage was observed. Overall, the attack angle of rib in the first passage was dominant factor to heat transfer and flow patterns in turning region. Also, the channel with a guide vane showed enhanced heat transfer at the tip surface with reducing flow separation and recirculation.

  4. Displacer Diameter Effect in Displacer Pulse Tube Refrigerator

    Science.gov (United States)

    Zhu, Shaowei

    2017-12-01

    Gas driving displacer pulse tube refrigerators are one of the work recovery type of pulse tube refrigerators whose theoretical efficiency is the same as Stirling refrigerators'. Its cooling power is from the displacement of the displacer. Displace diameter, rod diameter and pressure drop of the regenerator influence the displacement, which are investigated by numerical simulation. It is shown that the displacement ratio of the displacer over the piston is almost not affected by the displacer diameter at the same rod diameter ratio, or displacer with different diameters almost has the same performance.

  5. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  6. Demineralized water flow cancelling experiments with ice plug into high diameter horizontal tube (300 nominal diameter)

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Valeca, S.; Corbescu, B.; Puiu, D.; Panaitescu, V. N.

    2015-01-01

    The isolation with ice plug of a high diameter horizontal pipeline section is a specific technique for repairs activities/ replacements of components owning to thermo-hydraulic installations working with liquid agents. The application of such technique don.t assumes stopping of the entire system. The ice plugging inside of the pipeline assumes using of a special device and of an own specific technology for application. The paper contains a brief description of the experimental technological facilities used, followed by setting off the main moments in evolution of two experimental tests carried out on the test section with 300 mm nominal diameter for demineralized water and, finally, by a brief results analysis and some conclusions. The paper is dedicated to the specialists working in the research and technological engineering. (authors)

  7. On hydraulics of capillary tubes

    Directory of Open Access Journals (Sweden)

    N.G. Aloyan

    2016-03-01

    Full Text Available The article considers the laws of motion of water in the capillary tubes, taken as a model for flowing well, on the analogical net count device. For capillary tube the lower limit value of flow rate is empirically determined above which the total hydraulic resistance of the capillary is practically constant. The specificity of the phenomenon is that the regime of motion, by a Reynolds number, for a given flow rate still remains laminar. This circumstance can perplex the specialists, so the author invites them to the scientific debate on the subject of study. Obviously, to identify the resulting puzzle it is necessary to conduct a series of experiments using capillaries of different lengths and diameters and with different values of overpressure. The article states that in tubes with very small diameter the preliminary magnitude of capillary rise of water in the presence of flow plays no role and can be neglected.

  8. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield

    Science.gov (United States)

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0–14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ13C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ13C, both hydraulic efficiency and embolism resistance were

  9. Platelet count/spleen diameter ratio: analysis of its capacity as a predictor of the existence of esophageal varices Índice contagem de plaquetas/diâmetro do baço: análise de sua capacidade como preditor da existência de varizes esofágicas

    Directory of Open Access Journals (Sweden)

    Ângelo Zambam de Mattos

    2010-09-01

    Full Text Available CONTEXT: Upper gastrointestinal bleeding associated to esophageal varices is the most dramatic complication of cirrhosis. It is recommended screening every cirrhotic for esophageal varices with endoscopy. OBJECTIVES: To evaluate the capacity of the platelet count/spleen diameter ratio in non-invasively predicting esophageal varices in a population of cirrhotics originated in an independent center from the one in which it was developed. METHODS: The study included patients from the ambulatory care clinic of cirrhosis of a Brazilian hospital and studied platelet count, spleen diameter and presence of esophageal varices, as well as Child and MELD scores. It used a cutoff value of 909 for the platelet count/spleen diameter ratio, as previously published. A sample of 139 patients was needed to grant results a 95% confidence level. RESULTS: The study included 164 cirrhotics, 56.7% male, with a mean age of 56.6 ± 11.6 years. In the univariate analysis, platelet count, spleen diameter, presence of ascites, Child and MELD scores and the platelet count/spleen diameter ratio were related to esophageal varices (PCONTEXTO: Hemorragia digestiva por varizes esofágicas é a complicação mais dramática da cirrose. É recomendada triagem de varizes esofágicas em todo o cirrótico. OBJETIVO: Avaliar o índice de contagem de plaquetas/diâmetro do baço como predição de varizes esofágicas em uma população distinta daquela em que ele foi desenvolvido. MÉTODOS: O estudo incluiu pacientes do ambulatório de cirrose de um hospital brasileiro quanto ao número de plaquetas, diâmetro ecográfico do baço, presença de varizes esofágicas, Child e MELD. O ponto de corte do índice foi de 909. Amostra de 139 pacientes foi estimada para conferir nível de confiança de 95%. RESULTADOS: Incluíram-se 164 cirróticos, 56,7% homens e com média de idade de 56,6 anos. Na análise univariada, número de plaquetas, diâmetro do baço, ascite, Child, MELD e o

  10. Plug & Play Control of Hydraulic Networks

    DEFF Research Database (Denmark)

    Jensen, Tom Nørgaard

    2012-01-01

    Process Control research program, which the work presented here is a part of. An industrial case study involving a large-scale hydraulic network with non-linear dynamics is studied. The hydraulic network underlies a district heating system, which provides heating water to a number of end-users in a city...... district. The case study considers a novel approach to the design of district heating systems in which the diameter of the pipes used in the system is reduced in order to reduce the heat losses in the system, thereby making it profitable to provide district heating to areas with low energy demands. The new...

  11. Hydraulic conductivity of rock fractures

    International Nuclear Information System (INIS)

    Zimmerman, R.W.; Bodvarsson, G.S.

    1994-10-01

    Yucca Mountain, Nevada contains numerous geological units that are highly fractured. A clear understanding of the hydraulic conductivity of fractures has been identified as an important scientific problem that must be addressed during the site characterization process. The problem of the flow of a single-phase fluid through a rough-walled rock fracture is discussed within the context of rigorous fluid mechanics. The derivation of the cubic law is given as the solution to the Navier-Stokes equations for flow between smooth, parallel plates, the only fracture geometry that is amenable to exact treatment. The various geometric and kinetic conditions that are necessary in order for the Navier-Stokes equations to be replaced by the more tractable lubrication or Hele-Shaw equations are studied and quantified. Various analytical and numerical results are reviewed pertaining to the problem of relating the effective hydraulic aperture to the statistics of the aperture distribution. These studies all lead to the conclusion that the effective hydraulic aperture is always less than the mean aperture, by a factor that depends on the ratio of the mean value of the aperture to its standard deviation. The tortuosity effect caused by regions where the rock walls are in contact with each other is studied using the Hele-Shaw equations, leading to a simple correction factor that depends on the area fraction occupied by the contact regions. Finally, the predicted hydraulic apertures are compared to measured values for eight data sets from the literature for which aperture and conductivity data were available on the same fracture. It is found that reasonably accurate predictions of hydraulic conductivity can be made based solely on the first two moments of the aperture distribution function, and the proportion of contact area. 68 refs

  12. Heavy browsing affects the hydraulic capacity of Ceanothus rigidus (Rhamnaceae).

    Science.gov (United States)

    Pittermann, Jarmila; Lance, Jonathan; Poster, Lauren; Baer, Alex; Fox, Laurel R

    2014-07-01

    Defoliation by herbivores can reduce carbon assimilation, change plant water relations, and even shift the biotic structure of plant communities. In this study, we took advantage of a long-term deer exclosure experiment to examine the consequences of persistent deer herbivory on plant water relations and the xylem structure-function relationships in Ceanothus rigidus, a maritime chaparral shrub in coastal California. Browsed plants had thicker stems with many intertwined short distal twigs, and significantly higher sapwood-to-leaf area ratios than their non-browsed counterparts. Leaf area-specific hydraulic conductivity was similar in both browsed and non-browsed plants, but xylem area-specific conductivity was significantly lower in the browsed plants. Vessel diameters were equivalent in both plant groups, but the number of vessels on a transverse area basis was nearly 40% lower in the browsed plants, accounting for their lower transport efficiency. Mid-day in situ water potentials and losses of hydraulic conductivity due to embolism were similar in both groups of plants but stomatal conductance was higher in the browsed shrubs in the early part of the growing season. We discuss our findings in the context of whole-plant ecophysiology, and explore the consequences of herbivory on hormonal signals, wood anatomy, and xylem function.

  13. Fission tracks diameters in glasses

    International Nuclear Information System (INIS)

    Garzon Ruiperez, L.; Veiguela, J.

    1974-01-01

    Standard glass microscope slides have been irradiated with fission fragments from the uranium. The etching track conditions have been the same for the series, having changed the etching time only for each specimen. For each glass, a minimum of 250 measurements of the tracks diameters have been made, the distributions of which are the bimodal type. Diameters-etching dependence with time is roughly lineal. Energy determinations have been made with the help of the diameters-energy relations. The calculated values agree very well with the know ones. (author) [es

  14. Thermally Actuated Hydraulic Pumps

    Science.gov (United States)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  15. Diameter 2 properties and convexity

    Czech Academy of Sciences Publication Activity Database

    Abrahamsen, T. A.; Hájek, Petr Pavel; Nygaard, O.; Talponen, J.; Troyanski, S.

    2016-01-01

    Roč. 232, č. 3 (2016), s. 227-242 ISSN 0039-3223 R&D Projects: GA ČR GA16-07378S Institutional support: RVO:67985840 Keywords : diameter 2 property * midpoint locally uniformly rotund * Daugavet property Subject RIV: BA - General Mathematics Impact factor: 0.535, year: 2016 https://www.impan.pl/pl/wydawnictwa/czasopisma-i-serie-wydawnicze/studia- mathematica /all/232/3/91534/diameter-2-properties-and-convexity

  16. Digital switched hydraulics

    Science.gov (United States)

    Pan, Min; Plummer, Andrew

    2018-06-01

    This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

  17. Hydraulic Structures : Caissons

    NARCIS (Netherlands)

    Voorendt, M.Z.; Molenaar, W.F.; Bezuyen, K.G.

    These lecture notes on caissons are part of the study material belonging to the course 'Hydraulic Structures 1' (code CTB3355), part of the Bachelor of Science education and the Hydraulic Engineering track of the Master of Science education for civil engineering students at Delft University of

  18. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  19. Handbook of hydraulic fluid technology

    CERN Document Server

    Totten, George E

    2011-01-01

    ""The Handbook of Hydraulic Fluid Technology"" serves as the foremost resource for designing hydraulic systems and for selecting hydraulic fluids used in engineering applications. Featuring new illustrations, data tables, as well as practical examples, this second edition is updated with essential information on the latest hydraulic fluids and testing methods. The detailed text facilitates unparalleled understanding of the total hydraulic system, including important hardware, fluid properties, and hydraulic lubricants. Written by worldwide experts, the book also offers a rigorous overview of h

  20. Experimental study of the hydraulic jump in a hydraulic jump in a ...

    African Journals Online (AJOL)

    The hydraulic jump in a sloped rectangular channel is theoretically and experimentally examined. The study aims to determine the effect of the channel's slope on the sequent depth ratio of the jump. A theoretical relation is proposed for the inflow Froude number as function of the sequent depth ratio and the channel slope.

  1. DESIGN OF PARTICULATE MATERIAL COMPACTOR ROLLS DIAMETER

    Directory of Open Access Journals (Sweden)

    Peter Peciar

    2017-09-01

    Full Text Available At present, in a period of an industrial expansion great emphasis is placed on the environment. That means aiming for a reduced energy consumption, and also lessening dustiness from very fine powder material. This category also includes particulate material agglomeration processes. Because this process is very energy-intensive, it is necessary to correctly design these devices. The aim of this paper is to focus on a theoretical design of a production compactor with the rolls diameter for an experimental particulate material, based on Johanson’s theory and experimentally measured material properties. The material used for experimental measurements was an NPK-based industrial fertilizer consisting of several components. The results of this paper is the dependence of the ratio of the maximum compression pressure to the initial compression pressure from the rolls diameter of the proposed compactor.

  2. Hydraulic Yaw System

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Mørkholt, M.

    a hydraulic soft yaw system, which is able to reduce the loads on the wind turbine significantly. A full scale hydraulic yaw test rig is available for experiments and tests. The test rig is presented as well as the system schematics of the hydraulic yaw system....... the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized to reduce loading in critical components. Results shows that a significant reduction in fatigue and extreme loads to the yaw...... system and rotor shaft when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. Based on the extrapolated loads, the duty cycles show that it is possible to construct...

  3. Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Conrad, Finn

    2005-01-01

    The paper presents research results using IT-Tools for CAD and dynamic modelling, simulation, analysis, and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. Matlab/Simulink and CATIA are used as IT-Tools. The contributions include results from on......-going research projects on fluid power and mechatronics based on tap water hydraulic servovalves and linear servo actuators and rotary vane actuators for motion control and power transmission. Development and design a novel water hydraulic rotary vane actuator for robot manipulators. Proposed mathematical...... modelling, control and simulation of a water hydraulic rotary vane actuator applied to power and control a two-links manipulator and evaluate performance. The results include engineering design and test of the proposed simulation models compared with IHA Tampere University’s presentation of research...

  4. Hydraulic hoisting and backfilling

    Science.gov (United States)

    Sauermann, H. B.

    In a country such as South Africa, with its large deep level mining industry, improvements in mining and hoisting techniques could result in substantial savings. Hoisting techniques, for example, may be improved by the introduction of hydraulic hoisting. The following are some of the advantages of hydraulic hoisting as against conventional skip hoisting: (1) smaller shafts are required because the pipes to hoist the same quantity of ore hydraulically require less space in the shaft than does skip hoisting equipment; (2) the hoisting capacity of a mine can easily be increased without the necessity of sinking new shafts. Large savings in capital costs can thus be made; (3) fully automatic control is possible with hydraulic hoisting and therefore less manpower is required; and (4) health and safety conditions will be improved.

  5. The hydraulic wheel

    International Nuclear Information System (INIS)

    Alvarez Cardona, A.

    1985-01-01

    The present article this dedicated to recover a technology that key in disuse for the appearance of other techniques. It is the hydraulic wheel with their multiple possibilities to use their energy mechanical rotational in direct form or to generate electricity directly in the fields in the place and to avoid the high cost of transport and transformation. The basic theory is described that consists in: the power of the currents of water and the hydraulic receivers. The power of the currents is determined knowing the flow and east knowing the section of the flow and its speed; they are given you formulate to know these and direct mensuration methods by means of floodgates, drains and jumps of water. The hydraulic receivers or properly this hydraulic wheels that are the machines in those that the water acts like main force and they are designed to transmit the biggest proportion possible of absolute work of the water, the hydraulic wheels of horizontal axis are the common and they are divided in: you rotate with water for under, you rotate with side water and wheels with water for above. It is analyzed each one of them, their components are described; the conditions that should complete to produce a certain power and formulate them to calculate it. There are 25 descriptive figures of the different hydraulic wheels

  6. Hydraulic conductivity of compacted clay frozen and thawed in situ

    International Nuclear Information System (INIS)

    Benson, C.H.; Othman, M.A.

    1993-01-01

    A large specimen of compacted clay (diameter = 298 mm; thickness = 914 mm) was subjected to freeze-thaw in the field for 60 days. Afterward, the hydraulic conductivity was measured. The hydraulic conductivity of the entire specimen remained essentially unchanged, but increases in hydraulic conductivity of 1.5-2 orders of magnitude were observed above the freezing plane. The increase in hydraulic conductivity was highest at the top of the specimen and decreased with depth. Changes in hydraulic conductivity also occurred at depths 150 mm below the freezing plane, where desiccation occurred because of water redistribution. Numerous horizontal and vertical cracks formed in the soil mass. Dissection of the sample after permeation revealed that the cracks were laden with water. Cracking was greatest at the surface and became less frequent with depth. For depths greater than 150 mm below the freezing plane, cracking was absent. The frequency of cracks is consistent with principles of mechanistic models of soil freezing. The results of laboratory tests were used to predict the hydraulic conductivity of the large specimen. Tests were conducted on specimens subjected to various freeze-thaw cycles, temperature gradients, and states of stress. It was found that the predicted hydraulic conductivities were lower than those measured on the large specimen, but they closely resembled the trend in hydraulic conductivity with depth

  7. Diameter of the thoracic and abdominal aorta in healthy Japanese

    International Nuclear Information System (INIS)

    Matsunaga, Wakako

    1989-01-01

    In 300 cases, diameter of thoracic and abdominal aorta in healthy Japanese is measured by computed tomography (CT) and the values are analyzed in relation to the age, sex and the level of the aorta on CT scan. Aorta becomes dilated with age. In female diameter of the aorta is correlated with age, on the other hand, diameter of those is not correlated with age in male. Diameter in male is larger than in female. Aorta tapers off and the ratio of tapering of the thoracic aorta is more prominent than that of the abdominal aorta. Therefore the calculations of the landmarks of tapering of the aorta and the ratio of diameter of the aorta to transverse diameter of the vertebral body at the levels of 10th thoracic and 3rd lumber vertebrae on CT scan are useful for judgement of normal range of diameter of the aorta. Calcifications of the wall of the aorta are seen initially at the age of 5th decade in the abdominal aorta and 6th decade in the thoracic aorta in healthy Japanese. They are noted in almost of the persons after the age of seventy years old. The presence of calcification is not correlated with diameter of the aorta at the same level on CT scan. (author)

  8. The effect of diameter ratio between transducers and reactor in sonication-assisted synthesis of Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Manaf, A., E-mail: azwar@ui.ac.id; Fahmi, Agam Aidil [Department of Physics, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Yustanti, Erlina [Department of Physics, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Department of Metallurgy, Faculty of Engineering, University of Sultan AgengTirtayasa Jl. Jenderal Sudirman KM 03 Cilegon-Banten 65134 (Indonesia)

    2016-04-19

    This paper describes the particle size characterization of mechanically alloyed Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} prepared with the aid of a high-power ultrasonic destruction. Analytical-grade BaCO{sub 3}, TiO{sub 2} and SrCO{sub 3} with a purity greater than 99 wt.% were used as precursors for Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3}. The mechanically powders were respectively sintered at 1200 °C for 3 hours to form crystalline powders. This work is aimed at studying the effect of diameter ratio between reactor and transducer of a high power sonicator on the Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} nanoparticles formation. The presence of a single phase of the two materials was confirmed by X-Ray Diffraction (XRD). The concentration of the particles in demineralized water was 3.0 g / 100 mL which become the object of 3 hours ultrasonic destruction subjected to the application of transducer in which the ratio between the diameter of the reactor and the transducer (D/d) was fixed at 1.4, 1.6 and 1.8 respectively. It was found that the mean particle size before the ultrasonic destruction was 538 nm for Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and 480 nm for Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3}. With D/d of 1.8, the mean particle size of the two materials was found to decrease drastically to 38 nm and 24 nm, respectively. These mean particle sizes were respectively comparable with that of the crystallite size of the particles derived using the Whole Powder Pattern Modelling (WPPM) from which the mean crystallite size of 22 nm for Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and 14 nm for Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} were obtained. It is then confirmed single nanocrystallite Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} and Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} particles were already achieved. We can conclude that the ultrasonic destruction to mechanically milled crystalline particles would be one

  9. Esophagogastric junction distensibility measurements during hydraulic dilation therapy in achalasia patients

    NARCIS (Netherlands)

    Kappelle, W.F.; Bogte, A.; Siersema, P.D.

    2016-01-01

    Increasing evidence suggests that esophagogastric junction (EGJ) distensibility is predictive of long-term clinical success after achalasia treatment. A new commercially available hydraulic dilation balloon is capable of measuring EGJ opening diameters whilst simultaneously dilating the EGJ.

  10. Operation of a hydraulic elevator system

    Energy Technology Data Exchange (ETDEWEB)

    Lazarev, G.A.; Li, Yu.V.; Bezuglov, N.N.

    1983-03-01

    The paper describes the hydraulic elevator system in the im. 50-letiya Oktyabr'skoi Revolutsii mine in the Karaganda basin. The system removes water and coal from the sump of a skip mine shaft. Water influx rate per day to the sump does not exceed 120 m/sup 3/, weight of coal falling from the skip is about 5,000 kg per day. The sump, 85 m deep, is closed by a screen. The elevator system consists of two pumps (one is used as a reserve pump) with a capacity of 300 m/sup 3/h. When water level exceeds the maximum permissive limit the pump is activated by an automatic control system. The coal and water mixture pumped from the sump bottom is directed to a screen which separates coal from water. Coal is fed to a coal hopper and water is pumped to a water tank. The hydraulic elevator has a capacity of 80 m/sup 3/ of mixture per hour. The slurry is tranported by a pipe of 175 mm diameter. Specifications of the pumps and pipelines are given. A scheme of the hydraulic elevator system is also shown. Economic aspects of hydraulic elevator use for removal of water and coal from deep sumps of skip shafts in the Karaganda basin also are discussed.

  11. Experimental Study on Abrasive Waterjet Polishing of Hydraulic Turbine Blades

    International Nuclear Information System (INIS)

    Khakpour, H; Birglenl, L; Tahan, A; Paquet, F

    2014-01-01

    In this paper, an experimental investigation is implemented on the abrasive waterjet polishing technique to evaluate its capability in polishing of surfaces and edges of hydraulic turbine blades. For this, the properties of this method are studied and the main parameters affecting its performance are determined. Then, an experimental test-rig is designed, manufactured and tested to be used in this study. This test-rig can be used to polish linear and planar areas on the surface of the desired workpieces. Considering the number of parameters and their levels, the Taguchi method is used to design the preliminary experiments. All experiments are then implemented according to the Taguchi L 18 orthogonal array. The signal-to-noise ratios obtained from the results of these experiments are used to determine the importance of the controlled polishing parameters on the final quality of the polished surface. The evaluations on these ratios reveal that the nozzle angle and the nozzle diameter have the most important impact on the results. The outcomes of these experiments can be used as a basis to design a more precise set of experiments in which the optimal values of each parameter can be estimated

  12. Inferring diameters of spheres and cylinders using interstitial water.

    Science.gov (United States)

    Herrera, Sheryl L; Mercredi, Morgan E; Buist, Richard; Martin, Melanie

    2018-06-04

    Most early methods to infer axon diameter distributions using magnetic resonance imaging (MRI) used single diffusion encoding sequences such as pulsed gradient spin echo (SE) and are thus sensitive to axons of diameters > 5 μm. We previously simulated oscillating gradient (OG) SE sequences for diffusion spectroscopy to study smaller axons including the majority constituting cortical connections. That study suggested the model of constant extra-axonal diffusion breaks down at OG accessible frequencies. In this study we present data from phantoms to test a time-varying interstitial apparent diffusion coefficient. Diffusion spectra were measured in four samples from water packed around beads of diameters 3, 6 and 10 μm; and 151 μm diameter tubes. Surface-to-volume ratios, and diameters were inferred. The bead pore radii estimates were 0.60±0.08 μm, 0.54±0.06 μm and 1.0±0.1 μm corresponding to bead diameters ranging from 2.9±0.4 μm to 5.3±0.7 μm, 2.6±0.3 μm to 4.8±0.6 μm, and 4.9±0.7 μm to 9±1 μm. The tube surface-to-volume ratio estimate was 0.06±0.02 μm -1 corresponding to a tube diameter of 180±70 μm. Interstitial models with OG inferred 3-10 μm bead diameters from 0.54±0.06 μm to 1.0±0.1 μm pore radii and 151 μm tube diameters from 0.06±0.02 μm -1 surface-to-volume ratios.

  13. Hitungan Diameter Pipa pada Sistem Penyediaan Air Minum sederhana

    Directory of Open Access Journals (Sweden)

    Wahyu Widiyanto

    2010-02-01

    Full Text Available Drinking water sector is one of the public services which is connected tightly to poverty decrease. A small community water supply is more suitable if it uses a simple system which does not need sophisticated planning and construction. Nevertheless, hydraulics calculation should be always conducted accurately because it will influence water supply performance. In this case, pipe hydraulics needs more overview because system reliability depends on pipe capacity. This study discusses two methods of pipe diameter calculation at a simple drinking water supply system. For planning assistance, Directorate General Cipta Karya-Public Work Ministry issued Technical Guideline Book for Simple Drinking Water Construction in 2007. One of its chapters discusses about a method to find pipe diameter based on several tables available, but it is not given an explanation about basic theory of the tables so there is a doubt for planners. For the reason, comparison between the use of the tables (Juknis Method and Darcy-Weisbach Formula to calculate pipe diameter will be discussed. Data from 5 villages in Kebumen Regency will be utilized to support analysis. The result of procedure for making comparison shows that there is no significant difference (less than 4% between the result of calculation by Darcy-Weisbach Formula and Juknis Method with accurate interpolation. Both of the methods can be applied with its advantages and disadvantages. It is suggested that Darcy-Weisbach Formula is always implemented to re-check toward pipe diameter which is available in the market and will be used in the system.

  14. Fundamental test results of a hydraulic free piston internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Hibi, A.; Ito, T. [Toyohashi University of Technology (Japan). Dept. of Mechanical Engineering

    2004-10-01

    The hydraulic free piston internal combustion engine pump that has been constructed and tested in this work is the opposed piston, two-stroke cycle, uniflow scavenging, direct fuel injection, and compression ignition type. The opposed engine pistons reciprocate the hydraulic pump pistons directly and the hydraulic power to be used in the hydraulic motors is generated. The hydraulic pressure generated is substantially constant. The opposed free pistons rest after every gas cycle and hydraulic power is continuously supplied by a hydraulic accumulator during the free pistons' rest. The smaller the hydraulic flow output, the longer the duration of the rest. Every gas cycle is performed under a fixed working condition independent of hydraulic power output. The test results in this work indicate that the number of gas cycles per second of the free piston engine pump is directly proportional to hydraulic flow output. The opposed free pistons operate every 53.2 s when hydraulic flow output is 1.02 cm{sup 3}/s; at that time hydraulic power output is 0.0124 kW. Hydraulic thermal efficiency, the ratio of hydraulic energy produced to fuel energy consumed, has been measured in the range 0.0124 kW to 4.88 kW of hydraulic power output and it has become clear that hydraulic thermal efficiency in this range is constant. The measured value of hydraulic thermal efficiency is 31 per cent. It has been demonstrated that hydraulic thermal efficiency is kept constant even if hydraulic power output is very small. (author)

  15. Cavitation in Hydraulic Machinery

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldsen, M.

    1996-11-01

    The main purpose of this doctoral thesis on cavitation in hydraulic machinery is to change focus towards the coupling of non-stationary flow phenomena and cavitation. It is argued that, in addition to turbulence, superimposed sound pressure fluctuations can have a major impact on cavitation and lead to particularly severe erosion. For the design of hydraulic devices this finding may indicate how to further limit the cavitation problems. Chapter 1 reviews cavitation in general in the context of hydraulic machinery, emphasizing the initial cavitation event and the role of the water quality. Chapter 2 discusses the existence of pressure fluctuations for situations common in such machinery. Chapter 3 on cavitation dynamics presents an algorithm for calculating the nucleation of a cavity cluster. Chapter 4 describes the equipment used in this work. 53 refs., 55 figs.,10 tabs.

  16. Hydraulics and pneumatics

    CERN Document Server

    Parr, Andrew

    2006-01-01

    Nearly all industrial processes require objects to be moved, manipulated or subjected to some sort of force. This is frequently accomplished by means of electrical equipment (such as motors or solenoids), or via devices driven by air (pneumatics) or liquids (hydraulics).This book has been written by a process control engineer as a guide to the operation of hydraulic and pneumatic systems for all engineers and technicians who wish to have an insight into the components and operation of such a system.This second edition has been fully updated to include all recent developments su

  17. HYDRAULIC SERVO CONTROL MECHANISM

    Science.gov (United States)

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  18. Hydraulic Arm Modeling via Matlab SimHydraulics

    Czech Academy of Sciences Publication Activity Database

    Věchet, Stanislav; Krejsa, Jiří

    2009-01-01

    Roč. 16, č. 4 (2009), s. 287-296 ISSN 1802-1484 Institutional research plan: CEZ:AV0Z20760514 Keywords : simulatin modeling * hydraulics * SimHydraulics Subject RIV: JD - Computer Applications, Robotics

  19. Hydraulic and Condition Assessment of Existing Sewerage Network: A Case Study of an Educational Institute

    Science.gov (United States)

    Sourabh, Nishant; Timbadiya, P. V.

    2018-04-01

    The hydraulic simulation of the existing sewerage network provides various information about critical points to assess the deteriorating condition and help in rehabilitation of existing network and future expansion. In the present study, hydraulic and condition assessment of existing network of educational Institute (i.e. Sardar Vallabhbhai National Institute of Technology-Surat, Gujarat, India), having an area of 100 ha and ground levels in range of 5.0-9.0 m above mean sea level, has been carried out using sewage flow simulation for existing and future scenarios analysis using SewerGEMS v8i. The paper describes the features of 4.79 km long sewerage network of institute followed by network model simulation for aforesaid scenarios and recommendations on improvement of the existing network for future use. The total sewer loads for present and future scenarios are 1.67 million litres per day (MLD) and 3.62 MLD, considering the peak factor of 3 on the basis of population. The hydraulic simulation of the existing scenario indicated depth by diameter (d/D) ratio in the range of 0.02-0.48 and velocity range of 0.08-0.53 m/s for existing network for present scenario. For the future scenario, the existing network is needed to be modified and it was found that total of 11 conduits (length: 464.8 m) should be replaced to the next higher diameter available, i.e., 350 mm for utilization of existing network for future scenario. The present study provides the methodology for condition assessment of existing network and its utilization as per guidelines provided by Central Public Health and Environmental Engineering Organization, 2013. The methodology presented in this paper can be used by municipal/public health engineer for the assessment of existing sewerage network for its serviceability and improvement in future.

  20. Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density.

    Science.gov (United States)

    McCulloh, Katherine A; Meinzer, Frederick C; Sperry, John S; Lachenbruch, Barbara; Voelker, Steven L; Woodruff, David R; Domec, Jean-Christophe

    2011-09-01

    Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within mature individuals. While it is well established that wood density (WD) tends to be lower in early versus late successional tree species, and that WD can influence other aspects of PHA, the interaction of WD, successional stage and the consequent implications for PHA have not been sufficiently explored. Here, we studied differences in PHA at the scales of wood anatomy to whole-tree hydraulic conductance in species in early versus late successional Panamanian tropical forests. Although the trunk WD was indistinguishable between the successional groups, the branch WD was lower in the early successional species. Across all species, WD correlated negatively with vessel diameter and positively with vessel packing density. The ratio of branch:trunk vessel diameter, branch sap flux and whole-tree leaf-specific conductance scaled negatively with branch WD across species. Pioneer species showed greater sap flux in branches than in trunks and a greater leaf-specific hydraulic conductance, suggesting that pioneer species can move greater quantities of water at a given tension gradient. In combination with the greater water storage capacitance associated with lower WD, these results suggest these pioneer species can save on the carbon expenditure needed to build safer xylem and instead allow more carbon to be allocated to rapid growth.

  1. The hydraulic conductivity of sediments: A pore size perspective

    KAUST Repository

    Ren, X.W.

    2017-12-06

    This article presents an analysis of previously published hydraulic conductivity data for a wide range of sediments. All soils exhibit a prevalent power trend between the hydraulic conductivity and void ratio. Data trends span 12 orders of magnitude in hydraulic conductivity and collapse onto a single narrow trend when the hydraulic conductivity data are plotted versus the mean pore size, estimated using void ratio and specific surface area measurements. The sensitivity of hydraulic conductivity to changes in the void ratio is higher than the theoretical value due to two concurrent phenomena: 1) percolating large pores are responsible for most of the flow, and 2) the larger pores close first during compaction. The prediction of hydraulic conductivity based on macroscale index parameters in this and similar previous studies has reached an asymptote in the range of kmeas/5≤kpredict≤5kmeas. The remaining uncertainty underscores the important role of underlying sediment characteristics such as pore size distribution, shape, and connectivity that are not measured with index properties. Furthermore, the anisotropy in hydraulic conductivity cannot be recovered from scalar parameters such as index properties. Overall, results highlight the robustness of the physics inspired data scrutiny based Hagen–Poiseuille and Kozeny-Carman analyses.

  2. MODELING AND DESIGN OF INNOVATIVE SMALL DIAMETER GRAVITY SEWERAGE SYSTEM

    Directory of Open Access Journals (Sweden)

    Tadeusz Nawrot

    2017-05-01

    Full Text Available The article presents modern methods of hydraulic design of an innovative small diameter gravity sewerage system. In this system, domestic wastewater is preliminary treated in septic tanks equipped with outlet filters, thus the effluent features are similar to those of clear water. Innovative non-return valves at the outlets eliminate introduction of air to the system and thus the flows can be treated as one-phase ones. Computer codes EPANET 2 and SWMM 5.0 were applied and compared. Two flow schemes typical for the sewerage system were implemented in EPANET 2, and the third - in a slightly modified SWMM 5.0. Simulation results were validated on empirical data obtained on a laboratory physical model, consisting of four tanks of minimum volumes 600 dm3 each, connecting PE pipelines of diameters 25 mm and 36 mm and relevant sanitary fittings. Water inflows, typical for domestic wastewater outflows from single homesteads, were provided by a pump. Water flows were measured using water meters with pulse outputs, and water levels in tanks by pressure transducers. Hydraulic characteristics of filters and non-return valves were provided. Simulation results showed good agreement with the empirical data. Ranges of values of design parameters, needed for successful application of both codes, were established and discussed.

  3. CFD analysis of thermal-hydraulic behavior in SCWR typical flow channels

    International Nuclear Information System (INIS)

    Gu, H.Y.; Cheng, X.; Yang, Y.H.

    2008-01-01

    Investigations on thermal-hydraulic behavior in SCWR fuel assembly have obtained a significant attention in the international SCWR community. However, there is still a lack of understanding and ability to predict the heat transfer behavior of supercritical water. In this paper, CFD analysis is carried out to study the flow and heat transfer behavior of supercritical water in sub-channels of both square and triangular rod bundles. Effect of various parameters, e.g. thermal boundary conditions and pitch-to-diameter ratio on the thermal-hydraulic behavior is investigated. Two boundary conditions, i.e., constant heat flux at the outer surface of cladding and constant heat density in the fuel pin are applied. The results show that the structure of the secondary flow mainly depends on the rod bundle configuration as well as the pitch-to-diameter ratio, whereas, the amplitude of the secondary flow is affected by the thermal boundary conditions, as well. The secondary flow is much stronger in a square lattice than that in a triangular lattice. The turbulence behavior is similar in both square and triangular lattices. The dependence of the amplitude of the turbulent velocity fluctuation across the gap on Reynolds number becomes prominent in both lattices as the pitch-to-diameter ratio increases. The effect of thermal boundary conditions on turbulent velocity fluctuation is negligibly small. For both lattices with small pitch-to-diameter ratios (P/D < 1.3), the mixing coefficient is about 0.022. Both secondary flow and turbulent mixing show unusual behavior in the vicinity of the pseudo-critical point. Further investigation is needed. A strong circumferential non-uniformity of wall temperature and heat transfer is observed in tight lattices at constant heat flux boundary conditions, especially in square lattices. In the case with constant heat density of fuel pin, the circumferential conductive heat transfer significantly reduces the non-uniformity of circumferential

  4. Mine drivage in hydraulic mines

    Energy Technology Data Exchange (ETDEWEB)

    Ehkber, B Ya

    1983-09-01

    From 20 to 25% of labor cost in hydraulic coal mines falls on mine drivage. Range of mine drivage is high due to the large number of shortwalls mined by hydraulic monitors. Reducing mining cost in hydraulic mines depends on lowering drivage cost by use of new drivage systems or by increasing efficiency of drivage systems used at present. The following drivage methods used in hydraulic mines are compared: heading machines with hydraulic haulage of cut rocks and coal, hydraulic monitors with hydraulic haulage, drilling and blasting with hydraulic haulage of blasted rocks. Mining and geologic conditions which influence selection of the optimum mine drivage system are analyzed. Standardized cross sections of mine roadways driven by the 3 methods are shown in schemes. Support systems used in mine roadways are compared: timber supports, roof bolts, roof bolts with steel elements, and roadways driven in rocks without a support system. Heading machines (K-56MG, GPKG, 4PU, PK-3M) and hydraulic monitors (GMDTs-3M, 12GD-2) used for mine drivage are described. Data on mine drivage in hydraulic coal mines in the Kuzbass are discussed. From 40 to 46% of roadways are driven by heading machines with hydraulic haulage and from 12 to 15% by hydraulic monitors with hydraulic haulage.

  5. Coupled neutronic-thermal-hydraulics analysis in a coolant subchannel of a PWR using CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Felipe P.; Su, Jian, E-mail: sujian@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The high capacity of Computational Fluid Dynamics code to predict multi-dimensional thermal-hydraulics behaviour and the increased availability of capable computer systems are making that method a good tool to simulate phenomena of thermal-hydraulics nature in nuclear reactors. However, since there are no neutron kinetics models available in commercial CFD codes to the present day, the application of CFD in the nuclear reactor safety analyses is still limited. The present work proposes the implementation of the point kinetics model (PKM) in ANSYS - Fluent to predict the neutronic behaviour in a Westinghouse Sequoyah nuclear reactor, coupling with the phenomena of heat conduction in the rod and thermal-hydraulics in the cooling fluid, via the reactivity feedback. Firstly, a mesh convergence and turbulence model study was performed, using the Reynolds-Average Navier-Stokes method, with square arrayed rod bundle featuring pitch to diameter ratio of 1:32. Secondly, simulations using the k-! SST turbulence model were performed with an axial distribution of the power generation in the fuel to analyse the heat transfer through the gap and cladding, and its in fluence on the thermal-hydraulics behaviour of the cooling fluid. The wall shear stress distribution for the centre-line rods and the dimensionless velocity were evaluated to validate the model, as well as the in fluence of the mass flow rate variation on the friction factor. The coupled model enabled to perform a dynamic analysis of the nuclear reactor during events of insertion of reactivity and shutdown of primary coolant pumps. (author)

  6. Hydraulic architecture and tracheid allometry in mature Pinus palustris and Pinus elliottii trees.

    Science.gov (United States)

    Gonzalez-Benecke, C A; Martin, T A; Peter, G F

    2010-03-01

    Pinus palustris Mill. (longleaf pine, LL) and Pinus elliottii Engelm. var. elliottii (slash pine, SL) frequently co-occur in lower coastal plain flatwoods of the USA, with LL typically inhabiting slightly higher and better-drained microsites than SL. The hydraulic architecture and tracheid dimensions of roots, trunk and branches of mature LL and SL trees were compared to understand their role in species microsite occupation. Root xylem had higher sapwood-specific hydraulic conductivity (k(s)) and was less resistant to cavitation compared with branches and trunk sapwood. Root k(s) of LL was significantly higher than SL, whereas branch and trunk k(s) did not differ between species. No differences in vulnerability to cavitation were observed in any of the organs between species. Across all organs, there was a significant but weak trade-off between water conduction efficiency and safety. Tracheid hydraulic diameter (D(h)) was strongly correlated with k(s) across all organs, explaining >73% of the variation in k(s). In contrast, tracheid length (L(t)) explained only 2.4% of the variability. Nevertheless, for trunk xylem, k(s) was 39.5% higher at 20 m compared with 1.8 m; this increase in k(s) was uncorrelated with D(h) and cell-wall thickness but was strongly correlated with the difference in L(t). Tracheid allometry markedly changed between sapwood of roots, trunks and branches, possibly reflecting different mechanical constraints. Even though vulnerability to cavitation was not different for sapwood of roots, branches or the trunks of LL and SL, higher sapwood to leaf area ratio and higher maximum sapwood-specific hydraulic conductivity in roots of LL are functional traits that may provide LL with a competitive advantage on drier soil microsites.

  7. Sagittal Abdominal Diameter: Application in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Thaís Da Silva-Ferreira

    2014-05-01

    Full Text Available Excess visceral fat is associated with cardiovascular risk factors. Sagittal abdominal diameter (SAD has recently been highlighted as an indicator of abdominal obesity, and also may be useful in predicting cardiovascular risk. The purpose of the present study was to review the scientific literature on the use of SAD in adult nutritional assessment. A search was conducted for scientific articles in the following electronic databases: SciELO , MEDLINE (PubMed and Virtual Health Library. SAD is more associated with abdominal fat (especially visceral, and with different cardiovascular risk factors, such as, insulin resistance, blood pressure, and serum lipoproteins than the traditional methods of estimating adiposity, such as body mass index and waist-to-hip ratio. SAD can also be used in association with other anthropometric measures. There are still no cut-off limits established to classify SAD as yet. SAD can be an alternative measure to estimate visceral adiposity. However, the few studies on this diameter, and the lack of consensus on the anatomical site to measure SAD, are obstacles to establish cut-off limits to classify it.

  8. Hydraulic shock absorbers

    International Nuclear Information System (INIS)

    Thatcher, G.; Davidson, D. F.

    1984-01-01

    A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods

  9. Preparation of hydraulic cement

    Energy Technology Data Exchange (ETDEWEB)

    1921-08-28

    A process for the preparation of hydraulic cement by the use of oil-shale residues is characterized in that the oil-shale refuse is mixed with granular basic blast-furnace slag and a small amount of portland cement and ground together.

  10. Small hydraulic turbine drives

    Science.gov (United States)

    Rostafinski, W. A.

    1970-01-01

    Turbine, driven by the fluid being pumped, requires no external controls, is completely integrated into the flow system, and has bearings which utilize the main fluid for lubrication and cooling. Torque capabilities compare favorably with those developed by positive displacement hydraulic motors.

  11. Modelling of Hydraulic Robot

    DEFF Research Database (Denmark)

    Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik

    1997-01-01

    This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...

  12. Manual Hydraulic Structures

    NARCIS (Netherlands)

    Molenaar, W.F.; Voorendt, M.Z.

    This manual is the result of group work and origins in Dutch lecture notes that have been used since long time. Amongst the employees of the Hydraulic Engineering Department that contributed to this work are dr.ir. S. van Baars, ir.K.G.Bezuijen, ir.G.P.Bourguignon, prof.ir.A.Glerum,

  13. Water Treatment Technology - Hydraulics.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on hydraulics provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: head loss in pipes in series, function loss in…

  14. HANARO thermal hydraulic accident analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chul; Kim, Heon Il; Lee, Bo Yook; Lee, Sang Yong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    For the safety assessment of HANARO, accident analyses for the anticipated operational transients, accident scenarios and limiting accident scenarios were conducted. To do this, the commercial nuclear reactor system code. RELAP5/MOD2 was modified to RELAP5/KMRR; the thermal hydraulic correlations and the heat exchanger model was changed to incorporate HANARO characteristics. This report summarizes the RELAP/KMRR calculation results and the subchannel analyses results based on the RELAP/KMRR results. During the calculation, major concern was placed on the integrity of the fuel. For all the scenarios, the important accident analysis parameters, i.e., fuel centerline temperatures and the minimum critical heat flux ratio(MCHFR), satisfied safe design limits. It was verified, therefore, that the HANARO was safely designed. 21 tabs., 89 figs., 39 refs. (Author) .new.

  15. Cradle modification for hydraulic ram

    International Nuclear Information System (INIS)

    Koons, B.M.

    1995-01-01

    The analysis of the cradle hydraulic system considers stress, weld strength, and hydraulic forces required to lift and support the cradle/pump assembly. The stress and weld strength of the cradle modifications is evaluated to ensure that they meet the requirements of the American Institute for Steel Construction (AISC 1989). The hydraulic forces are evaluated to ensure that the hydraulic system is capable of rotating the cradle and pump assembly to the vertical position (between 70 degrees and 90 degrees)

  16. Hydraulic turbines and auxiliary equipment

    Energy Technology Data Exchange (ETDEWEB)

    Luo Gaorong [Organization of the United Nations, Beijing (China). International Centre of Small Hydroelectric Power Plants

    1995-07-01

    This document presents a general overview on hydraulic turbines and auxiliary equipment, emphasizing the turbine classification, in accordance with the different types of turbines, standard turbine series in China, turbine selection based on the basic data required for the preliminary design, general hill model curves, chart of turbine series and the arrangement of application for hydraulic turbines, hydraulic turbine testing, and speed regulating device.

  17. A diameter increment model for Red Fir in California and Southern Oregon

    Science.gov (United States)

    K. Leroy Dolph

    1992-01-01

    Periodic (10-year) diameter increment of individual red fir trees in Califomia and southern Oregon can be predicted from initial diameter and crown ratio of each tree, site index, percent slope, and aspect of the site. The model actually predicts the natural logarithm ofthe change in squared diameter inside bark between the startand the end of a 10-year growth period....

  18. Hydraulic Hybrid Vehicle Publications | Transportation Research | NREL

    Science.gov (United States)

    Hydraulic Hybrid Vehicle Publications Hydraulic Hybrid Vehicle Publications The following technical papers and fact sheets provide information about NREL's hydraulic hybrid fleet vehicle evaluations . Refuse Trucks Project Startup: Evaluating the Performance of Hydraulic Hybrid Refuse Vehicles. Bob

  19. [Root anatomical structure and hydraulic traits of three typical shrubs on the sandy lands of northern Shaanxi Province, China].

    Science.gov (United States)

    Ai, Shao-shui; Li, Yang-yang; Chen, Jia-cun; Chen, Wei-yue

    2015-11-01

    Root xylem anatomical structure and hydraulic traits of three typical shrubs, i.e., Salix psammophila, Caragana korshinskii and Hippophae rhamnoides, within two soil layers (0-20 cm and 30-50 cm) were compared. The results showed that S. psammophila had a higher leaf water potential than C. korshinskii and H. rhamnoides, the average maximum and minimum lumen diameter (d(max) and d(min), respectively), the average lumen area of vessels (Alum) and the ratio of lumen area of all vessels to xylem area (Aves/Axyl) in S. psammophila roots were also significantly higher than those in C. korshinskii and H. rhamnoides, and the root vessel density (VD) in S. psammophila was the same as that in H. rhamnoides but significantly higher than that in C. korshinskii. Root hydraulic conductivity in S. psammophila was 5 times of C. korshinskii and 2.8 times of H. hamnoides. The vulnerability index in S. psammophila roots was similar to that in C. korshinskii but higher than that in H. hamnoides. S. psammophila belonged to a water-spending species, whereas both C. korshinskii and H. rhamnoides were water-saving species, and C. korshinskii was more drought-resistant than H. rhamnoides. There was no difference of d(max), d(min) and Alum between roots in two soil layers, but roots within in the 30-50 cm soil layer had larger VD and Aves/Axyl. The root specific hydraulic conductivity within the 30-50 cm soil layer was significantly higher than within the surface soil layer, whereas the vulnerability index within the 30-50 cm soil layer was smaller, indicating roots in deep soil layers had higher hydraulic transport efficiency and lower hydraulic vulnerability.

  20. Diameter dependent electron transfer kinetics in semiconductor-enzyme complexes.

    Science.gov (United States)

    Brown, Katherine A; Song, Qing; Mulder, David W; King, Paul W

    2014-10-28

    Excited state electron transfer (ET) is a fundamental step for the catalytic conversion of solar energy into chemical energy. To understand the properties controlling ET between photoexcited nanoparticles and catalysts, the ET kinetics were measured for solution-phase complexes of CdTe quantum dots and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) using time-resolved photoluminescence spectroscopy. Over a 2.0-3.5 nm diameter range of CdTe nanoparticles, the observed ET rate (kET) was sensitive to CaI concentration. To account for diameter effects on CaI binding, a Langmuir isotherm and two geometric binding models were created to estimate maximal CaI affinities and coverages at saturating concentrations. Normalizing the ET kinetics to CaI surface coverage for each CdTe diameter led to k(ET) values that were insensitive to diameter, despite a decrease in the free energy for photoexcited ET (ΔGET) with increasing diameter. The turnover frequency (TOF) of CaI in CdTe-CaI complexes was measured at several molar ratios. Normalization for diameter-dependent changes in CaI coverage showed an increase in TOF with diameter. These results suggest that k(ET) and H2 production for CdTe-CaI complexes are not strictly controlled by ΔG(ET) and that other factors must be considered.

  1. Subchannel flow analysis in Candu and ACR pressure tubes with radial and axial diameter variation

    Energy Technology Data Exchange (ETDEWEB)

    Catana, A.; Prodea, L. [RAAN, Institute for Nuclear Research, Arges (Romania); Danila, N.; Prisecaru, I.; Dupleac, D. [Bucharest Univ. Politehnica(Romania)

    2007-07-01

    The Candu (Canada Deuterium Uranium) and ACR (Advanced Candu Reactor) are pressure tubes (PT) heavy water moderated reactors. Candu are heavy water and ACR are light water cooled reactors. The pressure tube is filled with 12 bundles, each consisting of 37 respectively 43 fuel rods. One Candu reactor is in operation at Cernavoda, Romania since 1996. ACR is a proposed advanced Candu. PT diameter variation has a significant impact on the thermal-hydraulic parameters. Almost all thermal-hydraulic parameters change, but some of them have a greater significance. In this work we have considered a set of radial and axial PT diameter variations both for Candu-600 and ACR-700 reactors using various types of fuel bundles. We can conclude the following: 1) some thermal-hydraulic parameters are significantly influenced: critical heat flux (CHF), pressure drop, or void fraction; 2) the most significant parameter CHF is worsening which reduces the safety margin; 3) some fuel types present a better thermal-hydraulic behavior; and 4) fuel bundles with fresh fuel or low burnup have a worse thermal-hydraulic behaviour than those at average burn-up.

  2. Subchannel flow analysis in Candu and ACR pressure tubes with radial and axial diameter variation

    International Nuclear Information System (INIS)

    Catana, A.; Prodea, L.; Danila, N.; Prisecaru, I.; Dupleac, D.

    2007-01-01

    The Candu (Canada Deuterium Uranium) and ACR (Advanced Candu Reactor) are pressure tubes (PT) heavy water moderated reactors. Candu are heavy water and ACR are light water cooled reactors. The pressure tube is filled with 12 bundles, each consisting of 37 respectively 43 fuel rods. One Candu reactor is in operation at Cernavoda, Romania since 1996. ACR is a proposed advanced Candu. PT diameter variation has a significant impact on the thermal-hydraulic parameters. Almost all thermal-hydraulic parameters change, but some of them have a greater significance. In this work we have considered a set of radial and axial PT diameter variations both for Candu-600 and ACR-700 reactors using various types of fuel bundles. We can conclude the following: 1) some thermal-hydraulic parameters are significantly influenced: critical heat flux (CHF), pressure drop, or void fraction; 2) the most significant parameter CHF is worsening which reduces the safety margin; 3) some fuel types present a better thermal-hydraulic behavior; and 4) fuel bundles with fresh fuel or low burnup have a worse thermal-hydraulic behaviour than those at average burn-up

  3. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany structures. This ratio comes from Fibonacci numbers.In this article, we explore this ...

  4. Golden Ratio

    Indian Academy of Sciences (India)

    Keywords. Fibonacci numbers, golden ratio, Sanskrit prosody, solar panel. Abstract. Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany ...

  5. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is sym- metrical and in proportion. If a face or a structure is in pro- portion, we are more likely to notice it and find it beautiful. The universal ratio of beauty is the 'Golden Ratio', found in many structures. This ratio comes from Fibonacci numbers. In this article, we explore this ...

  6. BRISENT: An Entropy-Based Model for Bridge-Pier Scour Estimation under Complex Hydraulic Scenarios

    Directory of Open Access Journals (Sweden)

    Alonso Pizarro

    2017-11-01

    Full Text Available The goal of this paper is to introduce the first clear-water scour model based on both the informational entropy concept and the principle of maximum entropy, showing that a variational approach is ideal for describing erosional processes under complex situations. The proposed bridge–pier scour entropic (BRISENT model is capable of reproducing the main dynamics of scour depth evolution under steady hydraulic conditions, step-wise hydrographs, and flood waves. For the calibration process, 266 clear-water scour experiments from 20 precedent studies were considered, where the dimensionless parameters varied widely. Simple formulations are proposed to estimate BRISENT’s fitting coefficients, in which the ratio between pier-diameter and sediment-size was the most critical physical characteristic controlling scour model parametrization. A validation process considering highly unsteady and multi-peaked hydrographs was carried out, showing that the proposed BRISENT model reproduces scour evolution with high accuracy.

  7. Hydraulic manipulator research at ORNL

    International Nuclear Information System (INIS)

    Kress, R.L.; Jansen, J.F.; Love, L.J.

    1997-01-01

    Recently, task requirements have dictated that manipulator payload capacity increase to accommodate greater payloads, greater manipulator length, and larger environmental interaction forces. General tasks such as waste storage tank cleanup and facility dismantlement and decommissioning require manipulator life capacities in the range of hundreds of pounds rather than tens of pounds. To meet the increased payload capacities demanded by present-day tasks, manipulator designers have turned once again to hydraulics as a means of actuation. In order to successfully design, build, and deploy a new hydraulic manipulator (or subsystem), sophisticated modeling, analysis, and control experiments are usually needed. Oak Ridge National Laboratory (ORNL) has a history of projects that incorporate hydraulics technology, including mobile robots, teleoperated manipulators, and full-scale construction equipment. In addition, to support the development and deployment of new hydraulic manipulators, ORNL has outfitted a significant experimental laboratory and has developed the software capability for research into hydraulic manipulators, hydraulic actuators, hydraulic systems, modeling of hydraulic systems, and hydraulic controls. The purpose of this article is to describe the past hydraulic manipulator developments and current hydraulic manipulator research capabilities at ORNL. Included are example experimental results from ORNL's flexible/prismatic test stand

  8. Hydraulic manipulator research at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Kress, R.L.; Jansen, J.F. [Oak Ridge National Lab., TN (United States); Love, L.J. [Oak Ridge Inst. for Science and Education, TN (United States)

    1997-03-01

    Recently, task requirements have dictated that manipulator payload capacity increase to accommodate greater payloads, greater manipulator length, and larger environmental interaction forces. General tasks such as waste storage tank cleanup and facility dismantlement and decommissioning require manipulator life capacities in the range of hundreds of pounds rather than tens of pounds. To meet the increased payload capacities demanded by present-day tasks, manipulator designers have turned once again to hydraulics as a means of actuation. In order to successfully design, build, and deploy a new hydraulic manipulator (or subsystem), sophisticated modeling, analysis, and control experiments are usually needed. Oak Ridge National Laboratory (ORNL) has a history of projects that incorporate hydraulics technology, including mobile robots, teleoperated manipulators, and full-scale construction equipment. In addition, to support the development and deployment of new hydraulic manipulators, ORNL has outfitted a significant experimental laboratory and has developed the software capability for research into hydraulic manipulators, hydraulic actuators, hydraulic systems, modeling of hydraulic systems, and hydraulic controls. The purpose of this article is to describe the past hydraulic manipulator developments and current hydraulic manipulator research capabilities at ORNL. Included are example experimental results from ORNL`s flexible/prismatic test stand.

  9. Mechanics of Hydraulic Fractures

    Science.gov (United States)

    Detournay, Emmanuel

    2016-01-01

    Hydraulic fractures represent a particular class of tensile fractures that propagate in solid media under pre-existing compressive stresses as a result of internal pressurization by an injected viscous fluid. The main application of engineered hydraulic fractures is the stimulation of oil and gas wells to increase production. Several physical processes affect the propagation of these fractures, including the flow of viscous fluid, creation of solid surfaces, and leak-off of fracturing fluid. The interplay and the competition between these processes lead to multiple length scales and timescales in the system, which reveal the shifting influence of the far-field stress, viscous dissipation, fracture energy, and leak-off as the fracture propagates.

  10. The radial flow method: constraints from laboratory experiments on the evolution of hydraulic properties of fractures during frictional sliding experiments

    Science.gov (United States)

    Kewel, M.; Renner, J.

    2017-12-01

    The variation of hydraulic properties during sliding events is of importance for source mechanics and analyses of the evolution in effective stresses. We conducted laboratory experiments on samples of Padang granite to elucidate the interrelation between shear displacement on faults and their hydraulic properties. The cylindrical samples of 30 mm diameter and 75 mm length were prepared with a ground sawcut, inclined 35° to the cylindrical axis and accessed by a central bore of 3 mm diameter. The conventional triaxial compression experiments were conducted at effective pressures of 30, 50, and 70 MPa at slip rates of 2×10-4 and 8×10-4 mm s-1. The nominally constant fluid pressure of 30 MPa was modulated by oscillations with an amplitude of up to 0.5 MPa. Permeability and specific storage capacity of the fault were determined using the oscillatory radial-flow method that rests on an analysis of amplitude ratio and phase shift between the oscillatory fluid pressure and the oscillatory fluid flow from and into the fault plane. This method allowed us to continuously monitor the hydraulic evolution during elastic loading and frictional sliding. The chosen oscillation period of 60 s guaranteed a resolution of hydraulic properties for slip increments as small as 20 μm. The determined hydraulic properties show a fairly uniform dependence on normal stress at hydrostatic conditions and initial elastic loading. The samples exhibited stable frictional sliding with modest strengthening with increasing strain. Since not all phase-shift values fell inside the theoretical range for purely radial pressure diffusion during frictional sliding, the records of equivalent hydraulic properties exhibit some gaps. In the phases with evaluable phase-shift values, permeability fluctuates by almost one order of magnitude over slip intervals of as little as 100 μm. We suppose that the observed fluctuations are related to comminution and reconfiguration of asperities on the fault planes

  11. HYDRAULIC AND PHYSICAL PROPERTIES OF MCU SALTSTONE

    International Nuclear Information System (INIS)

    Dixon, K; Mark Phifer, M

    2008-01-01

    The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone., Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement or lime to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of MCU (Modular Caustic Side Solvent Extraction Unit) saltstone relative to two permeating fluids. These fluids included simulated groundwater equilibrated with vault concrete and simulated saltstone pore fluid. Samples of the MCU saltstone were prepared by the Savannah River National Laboratory (SRNL) and allowed to cure for twenty eight days prior to testing. These samples included two three-inch diameter by six inch long mold samples and three one-inch diameter by twelve inch long mold samples

  12. HYDRAULIC AND PHYSICAL PROPERTIES OF MCU SALTSTONE

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, K; Mark Phifer, M

    2008-03-19

    The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone., Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement or lime to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of MCU (Modular Caustic Side Solvent Extraction Unit) saltstone relative to two permeating fluids. These fluids included simulated groundwater equilibrated with vault concrete and simulated saltstone pore fluid. Samples of the MCU saltstone were prepared by the Savannah River National Laboratory (SRNL) and allowed to cure for twenty eight days prior to testing. These samples included two three-inch diameter by six inch long mold samples and three one-inch diameter by twelve inch long mold samples.

  13. Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers.

    Science.gov (United States)

    Pittermann, Jarmila; Sperry, John

    2003-09-01

    We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-thaw cycle at -0.5 MPa in a centrifuge. Embolism increased as mean tracheid diameter exceeded 30 microm. Tracheids with a critical diameter greater than 43 microm were calculated to embolize in response to freezing and thawing at a xylem pressure of -0.5 MPa. To confirm that freezing-induced embolism is a function of conduit air content, we air-saturated stems of Abies lasiocarpa (Hook.) Nutt. (mean conduit diameter 13.7 +/- 0.7 microm) by pressurizing them 1 to 60 times above atmospheric pressure, prior to freezing and thawing. The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure. Embolism increased when the dissolved air content was equivalent to a mean tracheid diameter of 30 microm at ambient air pressure. Our centrifuge and air-saturation data show that conifers are as vulnerable to freeze-thaw embolism as angiosperms with equal conduit diameter. We suggest that the hydraulic conductivity of conifer wood is maximized by increasing tracheid diameters in locations where freezing is rare. Conversely, the narrowing of tracheid diameters protects against freezing-induced embolism in cold climates.

  14. Elevator and hydraulics; Elevator to yuatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, I. [Hitachi, Ltd., Tokyo (Japan)

    1994-07-15

    A hydraulic type elevator is installed in relatively lower buildings as compared with a rope type elevator, but the ratio in the number of installation of the former elevator is increasing. This paper explains from its construction and features to especially various control systems for the riding comfort and safety. A direct push-up system with hydraulic jacks arranged beneath a car, and an indirect push-up system that has hydraulic jacks arranged on flank of a car and transmits the movement of a plunger via a rope are available. The latter system eliminates the need of large holes to embed hydraulic jacks. While the speed is controlled by controlling flow rates of high-pressure oil, the speed, position, acceleration and even time differential calculus of the acceleration must be controlled severely. The system uses two-step control for the through-speed and the landing speed. Different systems that have been realized may include compensation for temperatures in flow rate control valves, load pressures, and oil viscosity, from learning control to fuzzy control for psychological effects, or control of inverters in motors. 13 refs., 12 figs., 1 tab.

  15. Highly reliable electro-hydraulic control system

    International Nuclear Information System (INIS)

    Mande, Morima; Hiyama, Hiroshi; Takahashi, Makoto

    1984-01-01

    The unscheduled shutdown of nuclear power stations disturbs power system, and exerts large influence on power generation cost due to the lowering of capacity ratio; therefore, high reliability is required for the control system of nuclear power stations. Toshiba Corp. has exerted effort to improve the reliability of the control system of power stations, and in this report, the electro-hydraulic control system for the turbines of nuclear power stations is described. The main functions of the electro-hydraulic control system are the control of main steam pressure with steam regulation valves and turbine bypass valves, the control of turbine speed and load, the prevention of turbine overspeed, the protection of turbines and so on. The system is composed of pressure sensors and a speed sensor, the control board containing the electronic circuits for control computation and protective sequence, the oil cylinders, servo valves and opening detectors of the valves for control, a high pressure oil hydraulic machine and piping, the operating panel and so on. The main features are the adoption of tripling intermediate value selection method, the multiplying of protection sensors and the adoption of 2 out of 3 trip logic, the multiplying of power sources, the improvement of the reliability of electronic circuit hardware and oil hydraulic system. (Kako, I.)

  16. Undular Hydraulic Jump

    Directory of Open Access Journals (Sweden)

    Oscar Castro-Orgaz

    2015-04-01

    Full Text Available The transition from subcritical to supercritical flow when the inflow Froude number Fo is close to unity appears in the form of steady state waves called undular hydraulic jump. The characterization of the undular hydraulic jump is complex due to the existence of a non-hydrostatic pressure distribution that invalidates the gradually-varied flow theory, and supercritical shock waves. The objective of this work is to present a mathematical model for the undular hydraulic jump obtained from an approximate integration of the Reynolds equations for turbulent flow assuming that the Reynolds number R is high. Simple analytical solutions are presented to reveal the physics of the theory, and a numerical model is used to integrate the complete equations. The limit of application of the theory is discussed using a wave breaking condition for the inception of a surface roller. The validity of the mathematical predictions is critically assessed using physical data, thereby revealing aspects on which more research is needed

  17. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  18. Tradeoffs between hydraulic and mechanical stress responses of mature Norway spruce trunk wood.

    Science.gov (United States)

    Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo

    2008-08-01

    We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in

  19. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    Directory of Open Access Journals (Sweden)

    Ye HUANG

    2014-09-01

    Full Text Available Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under light loads and wearing of the variable-displacement pump. To overcome these shortcomings, this article designs a closed hydraulic control system in which an AC servo motor drives a quantitative pump that controls a spiral swinging hydraulic cylinder, and analyzes and calculates the structure and parameters of a spiral swinging hydraulic cylinder. The hydraulic system adjusts the servo motor’s speed according to the requirements of the control system, and the motor power matches the power provided to components, thus eliminating the throttling loss of hydraulic circuits. The system is compact, produces a large output force, provides stable transmission, has a quick response, and is suitable as a hydraulic control system of a large butterfly valve.

  20. A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height

    Science.gov (United States)

    Katherine A. McCulloh; Daniel M. Johnson; Joshua Petitmermet; Brandon McNellis; Frederick C. Meinzer; Barbara Lachenbruch; Nathan Phillips

    2015-01-01

    The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter,...

  1. Effects of ring-porous and diffuse-porous stem wood anatomy on the hydraulic parameters used in a water flow and storage model.

    Science.gov (United States)

    Steppe, Kathy; Lemeur, Raoul

    2007-01-01

    Calibration of a recently developed water flow and storage model based on experimental data for a young diffuse-porous beech tree (Fagus sylvatica L.) and a young ring-porous oak tree (Quercus robur L.) revealed that differences in stem wood anatomy between species strongly affect the calibrated values of the hydraulic model parameters. The hydraulic capacitance (C) of the stem storage tissue was higher in oak than in beech (939.8 versus 212.3 mg MPa(-1)). Model simulation of the elastic modulus (epsilon) revealed that this difference was linked to the higher elasticity of the stem storage tissue of oak compared with beech. Furthermore, the hydraulic resistance (R (x)) of beech was about twice that of oak (0.1829 versus 0.1072 MPa s mg(-1)). To determine the physiological meaning of the R (x) parameter identified by model calibration, we analyzed the stem wood anatomy of the beech and oak trees. Calculation of stem specific hydraulic conductivity (k (s)) of beech and oak with the Hagen-Poiseuille equation confirmed the differences in R (x) predicted by the model. The contributions of different vessel diameter classes to the total hydraulic conductivity of the xylem were calculated. As expected, the few big vessels contributed much more to total conductivity than the many small vessels. Compared with beech, the larger vessels of oak resulted in a higher k (s) (10.66 versus 4.90 kg m(-1) s(-1) MPa(-1)). The calculated ratio of k (s) of oak to beech was 2, confirming the R (x) ratio obtained by model calibration. Thus, validation of the R (x) parameter of the model led to identification of its physiological meaning.

  2. Sauter mean diameter statistics of the starch dispersion atomized with hydraulic nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Naz, Muhammad Yasin, E-mail: yasin603@yahoo.com; Ariwahjoedi, Bambang, E-mail: bambang-ariwahjoedi@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Sulaiman, Shaharin Anwar, E-mail: shaharin@petronas.com.my [Department Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    In the reported research work, the microscopic droplet velocity at different axial and radial locations downstream to the nozzle exit was studied by using a non-intrusive Laser Doppler Anemometry (LDA) techniques. These velocity measurements made in the viscous fluid spray sterams were used to predict the different breakup regimes in the flow. It was noticed that the droplet velocity decreased sharply downstream to the nozzle exit, whereas steady decrease in velocity was seen along the radial directions. For shorter injection time periods, the velocity downstream to the nozzle was not following the general breakup model. However, along the radial direction it exactly followed the discussed model. Along the spray centerline, the velocity was decreasing sharply even at far points from the nozzle exit. It was difficult to identify the core region, transition region and fully developed spray region in the flow. It revealed that the jet breakup was not completed yet and further disintegration was taking place along the spray centerline for shorter injection periods below 250 ms.

  3. Sauter mean diameter statistics of the starch dispersion atomized with hydraulic nozzle

    International Nuclear Information System (INIS)

    Naz, Muhammad Yasin; Ariwahjoedi, Bambang; Sulaiman, Shaharin Anwar

    2015-01-01

    In the reported research work, the microscopic droplet velocity at different axial and radial locations downstream to the nozzle exit was studied by using a non-intrusive Laser Doppler Anemometry (LDA) techniques. These velocity measurements made in the viscous fluid spray sterams were used to predict the different breakup regimes in the flow. It was noticed that the droplet velocity decreased sharply downstream to the nozzle exit, whereas steady decrease in velocity was seen along the radial directions. For shorter injection time periods, the velocity downstream to the nozzle was not following the general breakup model. However, along the radial direction it exactly followed the discussed model. Along the spray centerline, the velocity was decreasing sharply even at far points from the nozzle exit. It was difficult to identify the core region, transition region and fully developed spray region in the flow. It revealed that the jet breakup was not completed yet and further disintegration was taking place along the spray centerline for shorter injection periods below 250 ms

  4. Study of ebullition inside a rectangular inclinable channel, of large hydraulic diameter

    International Nuclear Information System (INIS)

    Nehme, H.

    1997-01-01

    This work is performed in the framework of the investigation of-Severe Accidents of Water Cooled Nuclear Power Plants (PWR). A concept of molten core recovery is based on a retention in the lower head of the reactor vessel or in core-catchers which are externally cooled by water, Critical heat flux must be avoided in this external natural convection two-phase flow. The SULTAN experiment has been launched in order to investigate two-phase flow characteristics at experiment is described. Tests are performed under forced convection conditions for extended analytical investigation of the flow characteristics. They are mainly aimed to measure pressure drops, onset of critical heat flux (CHF), temperature and void fraction profiles in the flow. These results are describe and analyzed in a second part. The flow reveals to be very different from the classical flow in narrow channels. The difference is mainly due to 2-D effects and internal flow re-circulations. The limit of validity of 1-D analytical description of the flow is tested. This approach is improved by the proposal of a new correlation for the prediction of net vapor generation point and for the calculation of the mean density along the subcooled part of the flow. New CHF correlations are proposed. CHF is shown to be the same order of magnitude as these measured on the ULPU facility in UCSB and at the MIT. However 1-D approach has limitations at high qualities for large and inclined channels. A better description must be linked to the use of multi-dimensional numerical two-phase flow codes. (author)

  5. Sauter mean diameter statistics of the starch dispersion atomized with hydraulic nozzle

    Science.gov (United States)

    Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariwahjoedi, Bambang

    2015-07-01

    In the reported research work, the microscopic droplet velocity at different axial and radial locations downstream to the nozzle exit was studied by using a non-intrusive Laser Doppler Anemometry (LDA) techniques. These velocity measurements made in the viscous fluid spray sterams were used to predict the different breakup regimes in the flow. It was noticed that the droplet velocity decreased sharply downstream to the nozzle exit, whereas steady decrease in velocity was seen along the radial directions. For shorter injection time periods, the velocity downstream to the nozzle was not following the general breakup model. However, along the radial direction it exactly followed the discussed model. Along the spray centerline, the velocity was decreasing sharply even at far points from the nozzle exit. It was difficult to identify the core region, transition region and fully developed spray region in the flow. It revealed that the jet breakup was not completed yet and further disintegration was taking place along the spray centerline for shorter injection periods below 250 ms.

  6. A hydraulic hybrid propulsion method for automobiles with self-adaptive system

    International Nuclear Information System (INIS)

    Wu, Wei; Hu, Jibin; Yuan, Shihua; Di, Chongfeng

    2016-01-01

    A hydraulic hybrid vehicle with the self-adaptive system is proposed. The mode-switching between the driving mode and the hydraulic regenerative braking mode is realised by the pressure cross-feedback control. Extensive simulated and tested results are presented. The control parameters are reduced and the energy efficiency can be increased by the self-adaptive system. The mode-switching response is fast. The response time can be adjusted by changing the controlling spool diameter of the hydraulic operated check valve in the self-adaptive system. The closing of the valve becomes faster with a smaller controlling spool diameter. The hydraulic regenerative braking mode can be achieved by changing the hydraulic transformer controlled angle. Compared with the convention electric-hydraulic system, the self-adaptive system for the hydraulic hybrid vehicle mode-switching has a higher reliability and a lower cost. The efficiency of the hydraulic regenerative braking is also increased. - Highlights: • A new hybrid system with a self-adaptive system for automobiles is presented. • The mode-switching is realised by the pressure cross-feedback control. • The energy efficiency can be increased with the self-adaptive system. • The control parameters are reduced with the self-adaptive system.

  7. Application study of magnetic fluid seal in hydraulic turbine

    International Nuclear Information System (INIS)

    Yu, Z Y; Zhang, W

    2012-01-01

    The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

  8. Hydraulic Stability of Accropode Armour

    DEFF Research Database (Denmark)

    Jensen, T.; Burcharth, H. F.; Frigaard, Peter

    The present report describes the hydraulic model tests of Accropode armour layers carried out at the Hydraulics Laboratory at Aalborg University from November 1995 through March 1996. The objective of the model tests was to investigate the hydraulic stability of Accropode armour layers...... with permeable core (crushed granite with a gradation of 5-8 mm). The outcome of this study is described in "Hydraulic Stability of Single-Layer Dolos and Accropode Armour Layers" by Christensen & Burcharth (1995). In January/February 1996, Research Assistant Thomas Jensen carried out a similar study...

  9. Thermal hydraulic behavior of sub-assembly local blockage in China experiment fast reactor

    International Nuclear Information System (INIS)

    Yang Zhimin

    2000-01-01

    The geometrical parameter ratio of pitch to diameter of China Experiment Fast Reactor (CEFR) subassembly is 1,167. To address the thermal hydraulic behavior of subassembly local blockage which may be caused by deformation of cladding due to severe swelling and thermal stresses and by space swirl loosening etc., the porous numerical model and SIMPLE-P code used to solve Navier-Stokes and energy equations in porous medium was developed, and the bundle experiment with 19 pins with 24 subchannels blocked in the sodium coolant was carried on in China Institute of Atomic Energy (CIAE). The comparison of code predictions against experiments (including non-blockage and ten blockage conditions) seems well. The thermal hydraulic behavior of fuel subassembly with 61 fuel pins blockage of CEFR is calculated with SIMPLE-P code. The results indicate that the maximum temperature is 815 deg. C when the blockage area is about 37% (54 central subchannels are blocked). In this case the cladding won't be damaged and no sodium coolant boiling takes place. (author)

  10. Diameter-speed relation of sprite streamers

    International Nuclear Information System (INIS)

    Kanmae, T; Stenbaek-Nielsen, H C; McHarg, M G; Haaland, R K

    2012-01-01

    Propagation and splitting of sprite streamers has been observed at high temporal and spatial resolution using two intensified high-speed CMOS cameras recording at 10 000 and 16 000 frames per second. Concurrent video recordings from a remote site provided data for triangulation allowing us to determine accurate altitude scales for the sprites. Diameters and speeds of the sprite streamers were measured from the high-speed images, and the diameters were scaled to the reduced diameters based on the triangulated locations. The sprite streamers with larger reduced diameter move faster than those with smaller diameter; the relation between the reduced diameter and speed is roughly linear. The reduced diameters at ≈65-70 km altitude are larger than streamer diameters measured at ground pressure in laboratory discharges indicating a deviation from the similarity law possibly due to the effects of the photoionization and an expansion of the streamer head along its propagation over a long distance. The reduced diameter and speed of the sprite streamers agree well with the diameter-velocity relation proposed by Naidis (2009 Phys. Rev. E 79 057401), and the peak electric field of the sprite streamers is estimated to be approximately 3-5 times the breakdown threshold field. (paper)

  11. Hydraulic fracturing proppants

    Directory of Open Access Journals (Sweden)

    V. P. P. de Campos

    Full Text Available Abstract Hydrocarbon reservoirs can be classified as unconventional or conventional depending on the oil and gas extraction difficulty, such as the need for high-cost technology and techniques. The hydrocarbon extraction from bituminous shale, commonly known as shale gas/oil, is performed by using the hydraulic fracturing technique in unconventional reservoirs where 95% water, 0.5% of additives and 4.5% of proppants are used. Environmental problems related to hydraulic fracturing technique and better performance/development of proppants are the current challenge faced by companies, researchers, regulatory agencies, environmentalists, governments and society. Shale gas is expected to increase USA fuel production, which triggers the development of new proppants and technologies of exploration. This paper presents a review of the definition of proppants, their types, characteristics and situation in the world market and information about manufacturers. The production of nanoscale materials such as anticorrosive and intelligent proppants besides proppants with carbon nanotubes is already carried out on a scale of tonnes per year in Belgium, Germany and Asia countries.

  12. Hydraulic jett mixing

    International Nuclear Information System (INIS)

    Ackerman, J.R.

    1989-01-01

    Efficient mixing of reactants into a waste stream has always been a problem in that there has been no mixer capable of combining all the elements of enhanced mixing into a single piece of equipment. Through the development of a mixing system for the mining industry to treat acid mine water containing heavy metals, a versatile new hydraulic jetting static mixer has been developed that has no moving parts and a clean bore with no internal components. This paper reports that the main goal of the development of the hydraulic jett mixer was to reduce the size of the tankage required for an acid mine drainage (AMD) treatment plant through development of a static mixing device that could coincidentally aerate the treatment flow. This process equipment being developed would simultaneously adjust the pH and oxidize the metals allowing formation of the hydroxide sludges required for sedimentation and removal of the metals from the treatment stream. In effect, the device eliminates two reaction tanks, the neutralization/mixing tank and the aeration tank

  13. Applied hydraulic transients

    CERN Document Server

    Chaudhry, M Hanif

    2014-01-01

    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  14. Two-phase flow structure in large diameter pipes

    International Nuclear Information System (INIS)

    Smith, T.R.; Schlegel, J.P.; Hibiki, T.; Ishii, M.

    2012-01-01

    Highlights: ► Local profiles of various quantities measured in large diameter pipe. ► Database for interfacial area in large pipes extended to churn-turbulent flow. ► Flow regime map confirms previous models for flow regime transitions. ► Data will be useful in developing interfacial area transport models for large pipes. - Abstract: Flow in large pipes is important in a wide variety of applications. In the nuclear industry in particular, understanding of flow in large diameter pipes is essential in predicting the behavior of reactor systems. This is especially true of natural circulation Boiling Water Reactor (BWR) designs, where a large-diameter chimney above the core provides the gravity head to drive circulation of the coolant through the reactor. The behavior of such reactors during transients and during normal operation will be predicted using advanced thermal–hydraulics analysis codes utilizing the two-fluid model. Essential to accurate two-fluid model calculations is reliable and accurate computation of the interfacial transfer terms. These interfacial transfer terms can be expressed as the product of one term describing the potential driving the transfer and a second term describing the available surface area for transfer, or interfacial area concentration. Currently, the interfacial area is predicted using flow regime dependent empirical correlations; however the interfacial area concentration is best computed through the use of the one-dimensional interfacial area transport equation (IATE). To facilitate the development of IATE source and sink term models in large-diameter pipes a fundamental understanding of the structure of the two-phase flow is essential. This understanding is improved through measurement of the local void fraction, interfacial area concentration and gas velocity profiles in pipes with diameters of 0.102 m and 0.152 m under a wide variety of flow conditions. Additionally, flow regime identification has been performed to

  15. Coordination of stem and leaf hydraulic conductance in southern California shrubs: a test of the hydraulic segmentation hypothesis.

    Science.gov (United States)

    Pivovaroff, Alexandria L; Sack, Lawren; Santiago, Louis S

    2014-08-01

    Coordination of water movement among plant organs is important for understanding plant water use strategies. The hydraulic segmentation hypothesis (HSH) proposes that hydraulic conductance in shorter lived, 'expendable' organs such as leaves and longer lived, more 'expensive' organs such as stems may be decoupled, with resistance in leaves acting as a bottleneck or 'safety valve'. We tested the HSH in woody species from a Mediterranean-type ecosystem by measuring leaf hydraulic conductance (Kleaf) and stem hydraulic conductivity (KS). We also investigated whether leaves function as safety valves by relating Kleaf and the hydraulic safety margin (stem water potential minus the water potential at which 50% of conductivity is lost (Ψstem-Ψ50)). We also examined related plant traits including the operating range of water potentials, wood density, leaf mass per area, and leaf area to sapwood area ratio to provide insight into whole-plant water use strategies. For hydrated shoots, Kleaf was negatively correlated with KS , supporting the HSH. Additionally, Kleaf was positively correlated with the hydraulic safety margin and negatively correlated with the leaf area to sapwood area ratio. Consistent with the HSH, our data indicate that leaves may act as control valves for species with high KS , or a low safety margin. This critical role of leaves appears to contribute importantly to plant ecological specialization in a drought-prone environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  16. Coupled neutronics/thermal-hydraulics for analysis of molten salt reactor

    International Nuclear Information System (INIS)

    Guo, Zhangpeng; Zhou, Jianjun; Zhang, Dalin; Chaudri, Khurrum Saleem; Tian, Wenxi; Su, Guanghui; Qiu, Suizheng

    2013-01-01

    Highlights: ► A multiple-channel analysis code (MAC) is developed to be coupled with MCNP. ► 1/8 of core is simulated in MCNP and thermal-hydraulic code. ► The coupling calculation can achieve stable state after a few iterations. ► The coupling calculation results are in reasonable agreement with the analytic solutions of the ORNL. ► Parametric studies of MSR are performed to provide valuable information for future design MSR. -- Abstract: The Generation IV International Forum (GIF) selected molten salt reactor (MSR) among six advanced reactor types. It is characterized by a liquid circulating fuel that also serves as coolant. In this study, a multiple-channel analysis code (MAC) is developed and it is coupled with MCNP4c to analyze the neutronics/thermal-hydraulics behavior of molten salt reactor experiment (MSRE). The MAC calculates thermal-hydraulic parameters, such as temperature distribution, flow distribution and pressure drop. MCNP4c performs the analysis of effective multiplication factor, neutron flux and power distribution. A linkage code is developed to exchange data between MAC and MCNP to implement coupling iteration process until the power convergence is achieved. The coupling calculation can achieve converged solution after a few iterations. The results are in reasonable agreement with the analytic solutions from the ORNL. For further design analysis, parametric studies are performed to provide valuable information for new design of MSR. The effect of inlet temperature, graphite to molten salt volume ratio (G/Ms) from varying channel diameter and different power levels on the effective multiplication factor, neutron flux, graphite lifetime and temperature distribution are discussed in detail

  17. Changes in hydraulic conductivity of sand-bentonite mixtures accompanied with alkaline alteration

    International Nuclear Information System (INIS)

    Yamaguchi, Tetsuji; Sawaguchi, Takuma; Tsukada, Manabu; Tanaka, Tadao

    2012-01-01

    Document available in extended abstract form only. Montmorillonite is the main constituent of bentonite clay buffer materials in radioactive waste repositories. Highly alkaline environments induced by cement based materials are likely to alter montmorillonite, and to deteriorate the physical and/or chemical properties of the buffer materials. The deterioration may cause variation in hydraulic conductivity of the buffer and induce major uncertainties in the radionuclide migration analysis. Empirical data on the variation of hydraulic conductivity are, however, scarce mainly because the alteration of compacted buffer materials, sand-bentonite mixture specimen, is extremely slow (1). In this study, laboratory experiments were performed to observe changes in hydraulic conductivity of sand-bentonite mixtures accompanied with their alkaline alteration using NaOH based solutions at 80 - 90 deg. C. Our preliminary attempt to degrade sand-bentonite mixture by permeating alkaline solutions was unsuccessful, in which the flow rate of water became unstable. This was interpreted as an artifact due to generation and stagnation of air in the mixture specimen. The water conduction experimental apparatus was modified by removing membrane filter and leaving only sintered stainless steel filter, and by equipping the pressurizing tank with a preheater. Three types of experiments were performed afterwards. Series-1: Multi step alteration / water-conduction experiments. Two sand-bentonite mixture specimens with 50 mm in diameter, 10 mm in thickness and 1,600 kg m -3 in dry density were applied to hydraulic conductivity measurement and alkaline alteration process alternately. The mixture ratio was 1:1 in dry weight. The hydraulic conductivity was determined by permeating the specimens with 1.0 mol L -1 NaCl solution at 40 deg. C. While the specimens were immersed in Si, Al and Ca-adjusted 1.0 mol L -1 NaOH solution at 90 deg. C to allow alteration. In the final water-conduction step, the

  18. Process of preparing hydraulic cement

    Energy Technology Data Exchange (ETDEWEB)

    1919-12-11

    A process of preparing hydraulic cement from oil shale or shale coke is characterized in that the oil shale or shale coke after the distillation is burned long and hot to liberate the usual amount of carbonic acid and then is fine ground to obtain a slow hardening hydraulic cement.

  19. Control rod drive hydraulic device

    International Nuclear Information System (INIS)

    Takekawa, Toru.

    1994-01-01

    The device of the present invention can reliably prevent a possible erroneous withdrawal of control rod driving mechanism when the pressure of a coolant line is increased by isolation operation of hydraulic control units upon periodical inspection for a BWR type reactor. That is, a coolant line is connected to the downstream of a hydraulic supply device. The coolant line is connected to a hydraulic control unit. A coolant hydraulic detection device and a pressure setting device are disposed to the coolant line. A closing signal line and a returning signal line are disposed, which connect the hydraulic supply device and a flow rate control valve for the hydraulic setting device. In the device of the present invention, even if pressure of supplied coolants is elevated due to isolation of hydraulic control units, the elevation of the hydraulic pressure can be prevented. Accordingly, reliability upon periodical reactor inspection can be improved. Further, the facility is simplified and the installation to an existent facility is easy. (I.S.)

  20. Hydraulically centered control rod

    International Nuclear Information System (INIS)

    Horlacher, W.R.; Sampson, W.T.; Schukei, G.E.

    1981-01-01

    A control rod suspended to reciprocate in a guide tube of a nuclear fuel assembly has a hydraulic bearing formed at its lower tip. The bearing includes a plurality of discrete pockets on its outer surface into which a flow of liquid is continuously provided. In one embodiment the flow is induced by the pressure head in a downward facing chamber at the end of the bearing. In another embodiment the flow originates outside the guide tube. In both embodiments the flow into the pockets produces pressure differences across the bearing which counteract forces tending to drive the rod against the guide tube wall. Thus contact of the rod against the guide tube is avoided

  1. Equipment for hydraulic testing

    International Nuclear Information System (INIS)

    Jacobsson, L.; Norlander, H.

    1981-07-01

    Hydraulic testing in boreholes is one major task of the hydrogeological program in the Stripa Project. A new testing equipment for this purpose was constructed. It consists of a downhole part and a surface part. The downhole part consists of two packers enclosing two test-sections when inflated; one between the packers and one between the bottom packer and the bottom of the borehole. A probe for downhole electronics is also included in the downhole equipment together with electrical cable and nylon tubing. In order to perform shut-in and pulse tests with high accuracy a surface controlled downhole valve was constructed. The surface equipment consists of the data acquisition system, transducer amplifier and surface gauges. In the report detailed descriptions of each component in the whole testing equipment are given. (Auth.)

  2. Effect of particle diameter of porous media on flow and heat transfer in a mixing tee

    International Nuclear Information System (INIS)

    Wang, Yongwei; Lu, Tao; Wang, Kuisheng

    2012-01-01

    Highlights: ► Three particle diameter cases of 28 mm, 14 mm and 7 mm were simulated by LES. ► With the diameter decreasing, mixing scale tends to decrease in the mixing tee. ► With the diameter decreasing, thermal mixing is weakened. ► With the diameter decreasing, the thermal stratification is obvious. ► When the particle diameter ratio is 4:2:1, pressure drop ratio is 1:2:4. -- Abstract: Numerical simulations have been carried out to investigate flow and heat transfer in a mixing tee filled with periodic sintered copper spheres. Three particle diameter cases of 28 mm, 14 mm and 7 mm with the array of 4 × 4, 8 × 8 and 16 × 16 at the same porosity of 0.3 have been calculated using large-eddy simulations and the Smagorinsky–Lilly sub-grid scale model. With the particle diameter decreasing, the mixture scale of hot and cold fluid tends to decrease in the mixing tee; the pressure drop of fluid flow through porous media increases. When the particle diameter ratios are 4:2:1 and the specific surface ratios are 1:2:4, the pressure drop ratios are 1:2:4; the thermal mixing in porous media is weakened because the temperature fluctuation decreases and the stratification of hot and cold fluids is observed.

  3. Improving the support characteristics of hydraulic fill

    Energy Technology Data Exchange (ETDEWEB)

    Corson, D. R.; Dorman, K. R.; Sprute, R. H.

    1980-05-15

    Extensive laboratory and field testing has defined the physical properties of hydraulic fill. Effect of void ratio on percolation rate has been quantified, and tests were developed to estimate waterflow through fill material in a given state underground. Beneficial effect on fill's support capability through addition of cement alone or in conjunction with vibratory compaction has been investigated. Two separate field studies in operating cut-and-fill mines measured vein-wall deformation and loads imposed on backfilled stopes. Technology has been developed that will effectively and efficiently dewater and densify ultra-fine-grained slurries typical of metal mine hydraulic backfill. At least two operators are using this electrokinetic technique to dewater slimes collected in underground sumps or impoundments. This technique opens up the possibility of using the total unclassified tailings product as a hydraulic backfill. Theoretical enhancement of ground support and rock-burst control through improved support capability will be tested in a full-scale mine stope installation. Both a horizontal layer and a vertical column of high modulus fill will be placed in an attempt to reduce stope wall closure, support more ground pressure, and lessen rock-burst occurrence.

  4. 7 CFR 51.320 - Diameter.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Grades of Apples Definitions § 51.320 Diameter. When measuring for minimum size, “diameter...

  5. Diameter-dependent coloration of silver nanowires

    International Nuclear Information System (INIS)

    Stewart, Mindy S; Qiu Chao; Jiang Chaoyang; Kattumenu, Ramesh; Singamaneni, Srikanth

    2011-01-01

    Silver nanowires were synthesized with a green method and characterized with microscopic and diffractometric methods. The correlation between the colors of the nanowires deposited on a solid substrate and their diameters was explored. Silver nanowires that appear similar in color in the optical micrographs have very similar diameters as determined by atomic force microscopy. We have summarized the diameter-dependent coloration for these silver nanowires. An optical interference model was applied to explain such correlation. In addition, microreflectance spectra were obtained from individual nanowires and the observed spectra can be explained with the optical interference theory. This work provides a cheap, quick and simple screening method for studying the diameter distribution of silver nanowires, as well as the diameter variations of individual silver nanowires, without complicated sample preparation.

  6. Estimation of ground water hydraulic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hvilshoej, Soeren

    1998-11-01

    The main objective was to assess field methods to determine ground water hydraulic parameters and to develop and apply new analysis methods to selected field techniques. A field site in Vejen, Denmark, which previously has been intensively investigated on the basis of a large amount of mini slug tests and tracer tests, was chosen for experimental application and evaluation. Particular interest was in analysing partially penetrating pumping tests and a recently proposed single-well dipole test. Three wells were constructed in which partially penetrating pumping tests and multi-level single-well dipole tests were performed. In addition, multi-level slug tests, flow meter tests, gamma-logs, and geologic characterisation of soil samples were carried out. In addition to the three Vejen analyses, data from previously published partially penetrating pumping tests were analysed assuming homogeneous anisotropic aquifer conditions. In the present study methods were developed to analyse partially penetrating pumping tests and multi-level single-well dipole tests based on an inverse numerical model. The obtained horizontal hydraulic conductivities from the partially penetrating pumping tests were in accordance with measurements obtained from multi-level slug tests and mini slug tests. Accordance was also achieved between the anisotropy ratios determined from partially penetrating pumping tests and multi-level single-well dipole tests. It was demonstrated that the partially penetrating pumping test analysed by and inverse numerical model is a very valuable technique that may provide hydraulic information on the storage terms and the vertical distribution of the horizontal and vertical hydraulic conductivity under both confined and unconfined aquifer conditions. (EG) 138 refs.

  7. Use of Plant Hydraulic Theory to Predict Ecosystem Fluxes Across Mountainous Gradients in Environmental Controls and Insect Disturbances

    Science.gov (United States)

    Ewers, B. E.; Pendall, E.; Reed, D. E.; Barnard, H. R.; Whitehouse, F.; Frank, J. M.; Massman, W. J.; Brooks, P. D.; Biederman, J. A.; Harpold, A. A.; Naithani, K. J.; Mitra, B.; Mackay, D. S.; Norton, U.; Borkhuu, B.

    2011-12-01

    While mountainous areas are critical for providing numerous ecosystem benefits at the regional scale, the strong gradients in environmental controls make predictions difficult. A key part of the problem is quantifying and predicting the feedback between mountain gradients and plant function which then controls ecosystem cycling. The emerging theory of plant hydraulics provides a rigorous yet simple platform from which to generate testable hypotheses and predictions of ecosystem pools and fluxes. Plant hydraulic theory predicts that plant controls over carbon, water, energy and nutrient fluxes can be derived from the limitation of plant water transport from the soil through xylem and out of stomata. In addition, the limit to plant water transport can be predicted by combining plant structure (e.g. xylem diameters or root-to-shoot ratios) and plant function (response of stomatal conductance to vapor pressure deficit or root vulnerability to cavitation). We evaluate the predictions of the plant hydraulic theory by testing it against data from a mountain gradient encompassing sagebrush steppe through subalpine forests (2700 to 3400 m). We further test the theory by predicting the carbon, water and nutrient exchanges from several coniferous trees in the same gradient that are dying from xylem dysfunction caused by blue-stain fungi carried by bark beetles. The common theme of both of these data sets is a change in water limitation caused by either changing precipitation along the mountainous gradient or lack of access to soil water from xylem-occluding fungi. Across all of the data sets which range in scale from individual plants to hillslopes, the data fit the predictions of plant hydraulic theory. Namely, there was a proportional tradeoff between the reference canopy stomatal conductance to water vapor and the sensitivity of that conductance to vapor pressure deficit that quantitatively fits the predictions of plant hydraulic theory. Incorporating this result into

  8. Effects of Specimen Diameters on the Distribution of Corrosion Fatigue Cracks

    OpenAIRE

    石原, 外美; 塩澤, 和章; 宮尾, 嘉寿

    1988-01-01

    The distribution of corrosion fatigue cracks observed on the un-notched round specimen surface differs with specimen diameter, especially in the low stress amplitude region. At a constant fatigue life ratio, many long cracks are initiated on the larger specimen, 12 mm (diameter), in comparison with the smaller specimen, 6 mm (diameter). On the other hand, in the high stress amplitude region of corrosion fatigue and fatigue in laboratory air, the distribution of cracks during the fatigue proce...

  9. Hydraulic Actuators with Autonomous Hydraulic Supply for the Mainline Aircrafts

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2014-01-01

    Full Text Available Applied in the aircraft control systems, hydraulic servo actuators with autonomous hydraulic supply, so-called, hydraulic actuators of integrated configuration, i.e. combination of a source of hydraulic power and its load in the single unit, are aimed at increasing control system reliability both owing to elimination of the pipelines connecting the actuator to the hydraulic supply source, and owing to avoidance of influence of other loads failure on the actuator operability. Their purpose is also to raise control system survivability by eliminating the long pipeline communications and their replacing for the electro-conductive power supply system, thus reducing the vulnerability of systems. The main reason for a delayed application of the hydraulic actuators in the cutting-edge aircrafts was that such aircrafts require hydraulic actuators of considerably higher power with considerable heat releases, which caused an unacceptable overheat of the hydraulic actuators. Positive and negative sides of the hydraulic actuators, their alternative options of increased reliability and survivability, local hydraulic systems as an advanced alternative to independent hydraulic actuators are considered.Now to use hydraulic actuators in mainline aircrafts is inexpedient since there are the unfairly large number of the problems reducing, first and last, safety of flights, with no essential weight and operational advantages. Still works to create competitive hydraulic actuators ought to be continued.Application of local hydraulic systems (LHS will allow us to reduce length of pressure head and drain pipelines and mass of pipelines, as well as to raise their general fail-safety and survivability. Application of the LHS principle will allow us to use a majority of steering drive advantages. It is necessary to allocate especially the following:- ease of meeting requirements for the non-local spread of the engine weight;- essentially reducing length and weight of

  10. The hydraulic conductivity of sediments: A pore size perspective

    KAUST Repository

    Ren, X.W.; Santamarina, Carlos

    2017-01-01

    in the void ratio is higher than the theoretical value due to two concurrent phenomena: 1) percolating large pores are responsible for most of the flow, and 2) the larger pores close first during compaction. The prediction of hydraulic conductivity based

  11. Control of a hydraulically actuated continuously variable transmission

    NARCIS (Netherlands)

    Pesgens, M.F.M.; Vroemen, B.G.; Stouten, B.; Veldpaus, F.E.; Steinbuch, M.

    2006-01-01

    Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable

  12. Method to Estimate the Dissolved Air Content in Hydraulic Fluid

    Science.gov (United States)

    Hauser, Daniel M.

    2011-01-01

    In order to verify the air content in hydraulic fluid, an instrument was needed to measure the dissolved air content before the fluid was loaded into the system. The instrument also needed to measure the dissolved air content in situ and in real time during the de-aeration process. The current methods used to measure the dissolved air content require the fluid to be drawn from the hydraulic system, and additional offline laboratory processing time is involved. During laboratory processing, there is a potential for contamination to occur, especially when subsaturated fluid is to be analyzed. A new method measures the amount of dissolved air in hydraulic fluid through the use of a dissolved oxygen meter. The device measures the dissolved air content through an in situ, real-time process that requires no additional offline laboratory processing time. The method utilizes an instrument that measures the partial pressure of oxygen in the hydraulic fluid. By using a standardized calculation procedure that relates the oxygen partial pressure to the volume of dissolved air in solution, the dissolved air content is estimated. The technique employs luminescent quenching technology to determine the partial pressure of oxygen in the hydraulic fluid. An estimated Henry s law coefficient for oxygen and nitrogen in hydraulic fluid is calculated using a standard method to estimate the solubility of gases in lubricants. The amount of dissolved oxygen in the hydraulic fluid is estimated using the Henry s solubility coefficient and the measured partial pressure of oxygen in solution. The amount of dissolved nitrogen that is in solution is estimated by assuming that the ratio of dissolved nitrogen to dissolved oxygen is equal to the ratio of the gas solubility of nitrogen to oxygen at atmospheric pressure and temperature. The technique was performed at atmospheric pressure and room temperature. The technique could be theoretically carried out at higher pressures and elevated

  13. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    International Nuclear Information System (INIS)

    Shi, Q

    2010-01-01

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  14. Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Q, E-mail: qhshi@dfem.com.c [Dong Fang Electrical Machinery Co., Ltd., DEC 188, Huanghe West Road, Deyang, 618000 (China)

    2010-08-15

    This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

  15. Hydraulic release oil tool

    International Nuclear Information System (INIS)

    Mims, M.G.; Mueller, M.D.; Ehlinger, J.C.

    1992-01-01

    This patent describes a hydraulic release tool. It comprises a setting assembly; a coupling member for coupling to drill string or petroleum production components, the coupling member being a plurality of sockets for receiving the dogs in the extended position and attaching the coupling member the setting assembly; whereby the setting assembly couples to the coupling member by engagement of the dogs in the sockets of releases from and disengages the coupling member in movement of the piston from its setting to its reposition in response to a pressure in the body in exceeding the predetermined pressure; and a relief port from outside the body into its bore and means to prevent communication between the relief port and the bore of the body axially of the piston when the piston is in the setting position and to establish such communication upon movement of the piston from the setting position to the release position and reduce the pressure in the body bore axially of the piston, whereby the reduction of the pressure signals that the tool has released the coupling member

  16. HYDRAULICS, SHELBY COUNTY, KENTUCKY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  17. HYDRAULICS, MEADE COUNTY, KENTUCKY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulic data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

  18. The Process of Hydraulic Fracturing

    Science.gov (United States)

    Hydraulic fracturing, know as fracking or hydrofracking, produces fractures in a rock formation by pumping fluids (water, proppant, and chemical additives) at high pressure down a wellbore. These fractures stimulate the flow of natural gas or oil.

  19. Steam generator thermal-hydraulics

    International Nuclear Information System (INIS)

    Inch, W.W.; Scott, D.A.; Carver, M.B.

    1980-01-01

    This paper discusses a code for detailed numerical modelling of steam generator thermal-hydraulics, and describes related experimental programs designed to promote in-depth understanding of three-dimensional two-phase flow. (auth)

  20. Normal ureteral diameter in infancy and childhood

    International Nuclear Information System (INIS)

    Hellstroem, M.; Hjaelmaas, K.; Jacobsson, B.; Jodal, U.; Oden, A.; Oestra Sjukhuset, Goeteborg; Oestra Sjukhuset, Goeteborg; Goeteborg Univ.

    1985-01-01

    Ureteral diameters were estimated on films from intravenous urography in 194 children (100 boys and 94 girls) aged 0-16 years. Children with signs of urinary tract infection, calculi, obstruction, duplication or malformation were excluded. Films obtained without abdominal compression were used for measurements, including only ureters visualized over 50 per cent of their lengths. A good correlation was demonstrated between ureteral diameter and age and between ureteral diameter and the length of a segment of the lumbar spine. The widest part of the ureter was most often located just above the crossing of the iliac vessels. The right ureter was slightly wider than the left one. No difference between boys and girls was noted. The results are in good agreement with those of others obtained at autopsy. Bearing in mind the possible physiologic variations, it would seem that measuring the ureteral diameter can be of value for a more objective differentiation between dilated and non-dilated ureters. (orig.)

  1. SEX DETERMINATION FROM FEMORAL HEAD DIAMETERS IN ...

    African Journals Online (AJOL)

    hi-tech

    2000-03-01

    Mar 1, 2000 ... In medico-legal cases where sophisticated methods of sex determination is lacking, these ... scientific methods(3). Using the visual method ... between the sexes and the values of the right and left femoral head diameters.

  2. Analysis of pumping tests: Significance of well diameter, partial penetration, and noise

    Science.gov (United States)

    Heidari, M.; Ghiassi, K.; Mehnert, E.

    1999-01-01

    The nonlinear least squares (NLS) method was applied to pumping and recovery aquifer test data in confined and unconfined aquifers with finite diameter and partially penetrating pumping wells, and with partially penetrating piezometers or observation wells. It was demonstrated that noiseless and moderately noisy drawdown data from observation points located less than two saturated thicknesses of the aquifer from the pumping well produced an exact or acceptable set of parameters when the diameter of the pumping well was included in the analysis. The accuracy of the estimated parameters, particularly that of specific storage, decreased with increases in the noise level in the observed drawdown data. With consideration of the well radii, the noiseless drawdown data from the pumping well in an unconfined aquifer produced good estimates of horizontal and vertical hydraulic conductivities and specific yield, but the estimated specific storage was unacceptable. When noisy data from the pumping well were used, an acceptable set of parameters was not obtained. Further experiments with noisy drawdown data in an unconfined aquifer revealed that when the well diameter was included in the analysis, hydraulic conductivity, specific yield and vertical hydraulic conductivity may be estimated rather effectively from piezometers located over a range of distances from the pumping well. Estimation of specific storage became less reliable for piezemeters located at distances greater than the initial saturated thickness of the aquifer. Application of the NLS to field pumping and recovery data from a confined aquifer showed that the estimated parameters from the two tests were in good agreement only when the well diameter was included in the analysis. Without consideration of well radii, the estimated values of hydraulic conductivity from the pumping and recovery tests were off by a factor of four.The nonlinear least squares method was applied to pumping and recovery aquifer test data in

  3. Advanced Performance Hydraulic Wind Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.

    2013-01-01

    The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

  4. Robust Prediction of Hydraulic Roughness

    Science.gov (United States)

    2011-03-01

    Manning’s n were required as input for further hydraulic analyses with HEC - RAS . HYDROCAL was applied to compare different estimates of resistance... River Restoration Science Synthesis (NRRSS) demonstrated that, in 2007, river and stream restoration projects and funding were at an all time high...behavior makes this parameter very difficult to quan- tify repeatedly and accurately. A fundamental concept of hydraulic theory in the context of river

  5. Attempts to isolate a horizontal high diameter (300 mm nominal diameter) pipeline with an ice plug at minimum water flow and without water flow

    International Nuclear Information System (INIS)

    Corbescu, B.; Gyongyosi, T.; Puiu, D.; Panaitescu, V. N.

    2016-01-01

    The ice plug isolation technique used for high diameter horizontal pipes is used for repair and maintenance activities on hydraulic installations that use liquid working agents. These techniques do not require shutting down the entire plant. The ice plug development inside the pipe requires using custom specialized equipment for each individual application. This paper briefly describes the experimental technological facilities used for conducting the experiments and highlights the important aspects in an experiment conducted on a horizontal NPS 12 testing section running demineralized water followed by the result analysis and conclusions. The paper is dedicated to specialists working in research and technological engineering. (authors)

  6. Effective diameters and corresponding states of fluids

    Science.gov (United States)

    Del Río, Fernando

    Effective hard-sphere diameters of fluids with purely repulsive interactions are derived from a generalized corresponding-states principle of Leland, Rowlinson and coworkers. Various alternative definitions are discussed and related. Virial expansions of the effective diameters and their corresponding volumes are obtained and compared with results of perturbation theory. Applications are made to inverse-power potentials, the repulsive part of the Lennard-Jones potential and hard spherocylinders and dumbells.

  7. Appendiceal diameter: CT versus sonographic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Orscheln, Emily S. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati, OH (United States); Trout, Andrew T. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2016-03-15

    Ultrasound and CT are the dominant imaging modalities for assessment of suspected pediatric appendicitis, and the most commonly applied diagnostic criterion for both modalities is appendiceal diameter. The classically described cut-off diameter for the diagnosis of appendicitis is 6 mm when using either imaging modality. To demonstrate the fallacy of using the same cut-off diameter for both CT and US in the diagnosis of appendicitis. We conducted a retrospective review of patients younger than 18 years who underwent both US and CT of the appendix within 24 h. The shortest transverse dimension of the appendix was measured at the level of the proximal, mid and distal appendix on US and CT images. We compared mean absolute difference in appendiceal diameter between US and CT, using the paired t-test. We reviewed exams of 155 children (58.7% female) with a mean age of 11.3 ± 4.2 years; 38 of the children (24.5%) were diagnosed with appendicitis. The average time interval between US and CT was 7.0 ± 5.4 h. Mean appendiceal diameter measured by CT was significantly larger than that measured by US in cases without appendicitis (5.3 ± 1.0 mm vs. 4.7 ± 1.1 mm, P < 0.0001) and in cases with appendicitis (8.3 ± 2.2 mm vs. 7.0 ± 2.0 mm, P < 0.0001). Mean absolute diameter difference at any location along the appendix was 1.3-1.4 mm in normal appendices and 2 mm in cases of appendicitis. Measured appendiceal diameter differs between US and CT by 1-2 mm, calling into question use of the same diameter cut-off (6 mm) for both modalities for the diagnosis of appendicitis. (orig.)

  8. Small Diameter Bomb Increment II (SDB II)

    Science.gov (United States)

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-439 Small Diameter Bomb Increment II (SDB II) As of FY 2017 President’s Budget Defense... Bomb Increment II (SDB II) DoD Component Air Force Joint Participants Department of the Navy Responsible Office References SAR Baseline (Production...Mission and Description Small Diameter Bomb Increment II (SDB II) is a joint interest United States Air Force (USAF) and Department of the Navy

  9. Appendiceal diameter: CT versus sonographic measurements

    International Nuclear Information System (INIS)

    Orscheln, Emily S.; Trout, Andrew T.

    2016-01-01

    Ultrasound and CT are the dominant imaging modalities for assessment of suspected pediatric appendicitis, and the most commonly applied diagnostic criterion for both modalities is appendiceal diameter. The classically described cut-off diameter for the diagnosis of appendicitis is 6 mm when using either imaging modality. To demonstrate the fallacy of using the same cut-off diameter for both CT and US in the diagnosis of appendicitis. We conducted a retrospective review of patients younger than 18 years who underwent both US and CT of the appendix within 24 h. The shortest transverse dimension of the appendix was measured at the level of the proximal, mid and distal appendix on US and CT images. We compared mean absolute difference in appendiceal diameter between US and CT, using the paired t-test. We reviewed exams of 155 children (58.7% female) with a mean age of 11.3 ± 4.2 years; 38 of the children (24.5%) were diagnosed with appendicitis. The average time interval between US and CT was 7.0 ± 5.4 h. Mean appendiceal diameter measured by CT was significantly larger than that measured by US in cases without appendicitis (5.3 ± 1.0 mm vs. 4.7 ± 1.1 mm, P < 0.0001) and in cases with appendicitis (8.3 ± 2.2 mm vs. 7.0 ± 2.0 mm, P < 0.0001). Mean absolute diameter difference at any location along the appendix was 1.3-1.4 mm in normal appendices and 2 mm in cases of appendicitis. Measured appendiceal diameter differs between US and CT by 1-2 mm, calling into question use of the same diameter cut-off (6 mm) for both modalities for the diagnosis of appendicitis. (orig.)

  10. Effect of Tube Diameter on Heat Transfer to Vertically Upward Flowing Supercritical CO2

    International Nuclear Information System (INIS)

    Kang, Deog Ji; Kim, Sin; Bae, Yoon Yeong; Kim, Hwan Yeol; Kim, Hyung Rae

    2007-01-01

    Heat transfer characteristics of supercritical carbon dioxide are being investigated experimentally in the test loop named as SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt generation) at KAERI. The main purpose of the experiment is to provide a reliable heat transfer database for a SCWR (SuperCritical Water-cooled Reactor) by a prudent extension of the carbon dioxide test results to the estimation of a heat transfer for water. The produced data will be used in the thermo-hydraulic design of core and safety analysis for SCWR. The aim of the present paper is to study the influence of a tube diameter on a heat transfer. The experiments were completed for tubes of an inside diameter of 4.4mm and 9.0mm, respectively. The heat transfer characteristics from the two tubes of different diameters were compared and discussed

  11. Effect of Tube Diameter on Heat Transfer to Vertically Upward Flowing Supercritical CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Deog Ji; Kim, Sin [Cheju National University, Jeju (Korea, Republic of); Bae, Yoon Yeong; Kim, Hwan Yeol; Kim, Hyung Rae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    Heat transfer characteristics of supercritical carbon dioxide are being investigated experimentally in the test loop named as SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt generation) at KAERI. The main purpose of the experiment is to provide a reliable heat transfer database for a SCWR (SuperCritical Water-cooled Reactor) by a prudent extension of the carbon dioxide test results to the estimation of a heat transfer for water. The produced data will be used in the thermo-hydraulic design of core and safety analysis for SCWR. The aim of the present paper is to study the influence of a tube diameter on a heat transfer. The experiments were completed for tubes of an inside diameter of 4.4mm and 9.0mm, respectively. The heat transfer characteristics from the two tubes of different diameters were compared and discussed.

  12. Informational Entropy and Bridge Scour Estimation under Complex Hydraulic Scenarios

    Science.gov (United States)

    Pizarro, Alonso; Link, Oscar; Fiorentino, Mauro; Samela, Caterina; Manfreda, Salvatore

    2017-04-01

    Bridges are important for society because they allow social, cultural and economic connectivity. Flood events can compromise the safety of bridge piers up to the complete collapse. The Bridge Scour phenomena has been described by empirical formulae deduced from hydraulic laboratory experiments. The range of applicability of such models is restricted by the specific hydraulic conditions or flume geometry used for their derivation (e.g., water depth, mean flow velocity, pier diameter and sediment properties). We seek to identify a general formulation able to capture the main dynamic of the process in order to cover a wide range of hydraulic and geometric configuration, allowing to extend our analysis in different contexts. Therefore, exploiting the Principle of Maximum Entropy (POME) and applying it on the recently proposed dimensionless Effective flow work, W*, we derived a simple model characterized by only one parameter. The proposed Bridge Scour Entropic (BRISENT) model shows good performances under complex hydraulic conditions as well as under steady-state flow. Moreover, the model was able to capture the evolution of scour in several hydraulic configurations even if the model contains only one parameter. Furthermore, results show that the model parameter is controlled by the geometric configurations of the experiment. This offers a possible strategy to obtain a priori model parameter calibration. The BRISENT model represents a good candidate for estimating the time-dependent scour depth under complex hydraulic scenarios. The authors are keen to apply this idea for describing the scour behavior during a real flood event. Keywords: Informational entropy, Sediment transport, Bridge pier scour, Effective flow work.

  13. Retinal vessel diameter and estimated cerebrospinal fluid pressure in arterial hypertension: the Beijing Eye Study.

    Science.gov (United States)

    Jonas, Jost B; Wang, Ningli; Wang, Shuang; Wang, Ya Xing; You, Qi Sheng; Yang, Diya; Wei, Wen Bin; Xu, Liang

    2014-09-01

    Hypertensive retinal microvascular abnormalities include an increased retinal vein-to-artery diameter ratio. Because central retinal vein pressure depends on cerebrospinal fluid pressure (CSFP), we examined whether the retinal vein-to-artery diameter ratio and other retinal hypertensive signs are associated with CSFP. Participants of the population-based Beijing Eye Study (n = 1,574 subjects) underwent measurement of the temporal inferior and superior retinal artery and vein diameter. CSFP was calculated as 0.44 × body mass index (kg/m(2)) + 0.16 × diastolic blood pressure (mm Hg) - 0.18 × age (years) - 1.91. Larger retinal vein diameters and higher vein-to-artery diameter ratios were significantly associated with higher estimated CSFP (P = 0.001) in multivariable analysis. In contrast, temporal inferior retinal arterial diameter was marginally associated (P = 0.03) with estimated CSFP, and temporal superior artery diameter was not significantly associated (P = 0.10) with estimated CSFP; other microvascular abnormalities, such as arteriovenous crossing signs, were also not significantly associated with estimated CSFP. In a reverse manner, higher estimated CSFP as a dependent variable in the multivariable analysis was associated with wider retinal veins and higher vein-to-artery diameter ratio. In the same model, estimated CSFP was not significantly correlated with retinal artery diameters or other retinal microvascular abnormalities. Correspondingly, arterial hypertension was associated with retinal microvascular abnormalities such as arteriovenous crossing signs (P = 0.003), thinner temporal retinal arteries (P arterial hypertension, an increased retinal vein-to-artery diameter ratio depends on elevated CSFP, which is correlated with blood pressure. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. VIPRE-01. a thermal-hydraulic analysis code for reactor cores. Volume 1. Mathematical modeling

    International Nuclear Information System (INIS)

    Stewart, C.W.; Cuta, J.M.; Koontz, A.S.; Kelly, J.M.; Basehore, K.L.; George, T.L.; Rowe, D.S.

    1983-04-01

    VIPRE (Versatile Internals and Component Program for Reactors; EPRI) has been developed for nuclear power utility thermal-hydraulic analysis applications. It is designed to help evaluate nuclear reactor core safety limits including minimum departure from nucleate boiling ratio (MDNBR), critical power ratio (CPR), fuel and clad temperatures, and coolant state in normal operation and assumed accident conditions. This volume (Volume 1: Mathematical Modeling) explains the major thermal hydraulic models and supporting correlations in detail

  15. Automated software for hydraulic simulation of pipeline operation

    Directory of Open Access Journals (Sweden)

    Hurgin Roman

    2018-01-01

    Full Text Available Design of modern water supply systems of large cities as well as their management via renovation of hydraulic models poses time-consuming tasks to researchers, and coping with this task requires specific approaches. When tackling these tasks, water services companies come across a lot of information about various objects of water infrastructure, the majority of which is located underground. In those cases, modern computer-aided design systems containing various components come to help. These systems help to solve a wide array of problems using existing information regarding pipelines, analysis and optimization of their basic parameters. CAD software is becoming an integral part of water supply systems management in large cities, and its capabilities allow engineering and operating companies to not only collect all the necessary data concerning water supply systems in any given city, but also to conduct research aimed at improving various parameters of these systems, including optimization of their hydraulic properties which directly determine the quality of water. This paper contains the analysis of automated CAD software for hydraulic design and management of city water supply systems in order to provide safe and efficient operation of these water supply systems. Authors select the most suitable software that might be used to provide hydraulic compatibility of old and new sections of water supply ring mains after selective or continuous draw-in renovation and decrease in diameter of distribution networks against the background of water consumption decrease in the cities.

  16. Hydraulic testing in crystalline rock

    International Nuclear Information System (INIS)

    Almen, K.E.; Andersson, J.E.; Carlsson, L.; Hansson, K.; Larsson, N.A.

    1986-12-01

    Swedish Geolocical Company (SGAB) conducted and carried out single-hole hydraulic testing in borehole Fi 6 in the Finnsjoen area of central Sweden. The purpose was to make a comprehensive evaluation of different methods applicable in crystalline rocks and to recommend methods for use in current and scheduled investigations in a range of low hydraulic conductivity rocks. A total of eight different methods of testing were compared using the same equipment. This equipment was thoroughly tested as regards the elasticity of the packers and change in volume of the test section. The use of a hydraulically operated down-hole valve enabled all the tests to be conducted. Twelve different 3-m long sections were tested. The hydraulic conductivity calculated ranged from about 5x10 -14 m/s to 1x10 -6 m/s. The methods used were water injection under constant head and then at a constant rate-of-flow, each of which was followed by a pressure fall-off period. Water loss, pressure pulse, slug and drill stem tests were also performed. Interpretation was carried out using standard transient evaluation methods for flow in porous media. The methods used showed themselves to be best suited to specific conductivity ranges. Among the less time-consuming methods, water loss, slug and drill stem tests usually gave somewhat higher hydraulic conductivity values but still comparable to those obtained using the more time-consuming tests. These latter tests, however, provided supplementary information on hydraulic and physical properties and flow conditions, together with hydraulic conductivity values representing a larger volume of rock. (orig./HP)

  17. Developing high coercivity in large diameter cobalt nanowire arrays

    Science.gov (United States)

    Montazer, A. H.; Ramazani, A.; Almasi Kashi, M.; Zavašnik, J.

    2016-11-01

    Regardless of the synthetic method, developing high magnetic coercivity in ferromagnetic nanowires (NWs) with large diameters has been a challenge over the past two decades. Here, we report on the synthesis of highly coercive cobalt NW arrays with diameters of 65 and 80 nm, which are embedded in porous anodic alumina templates with high-aspect-ratio pores. Using a modified electrochemical deposition method enabled us to reach room temperature coercivity and remanent ratio up to 3000 Oe and 0.70, respectively, for highly crystalline as-synthesized hcp cobalt NW arrays with a length of 8 μm. The first-order reversal curve (FORC) analysis showed the presence of both soft and hard magnetic phases along the length of the resulting NWs. To develop higher coercive fields, the length of the NWs was then gradually reduced in order from bottom to top, thereby reaching NW sections governed by the hard phase. Consequently, this resulted in record high coercivities of 4200 and 3850 Oe at NW diameters of 65 and 80 nm, respectively. In this case, the FORC diagrams confirmed a significant reduction in interactions between the magnetic phases of the remaining sections of NWs. At this stage, x-ray diffraction (XRD) and dark-field transmission electron microscopy analyses indicated the formation of highly crystalline bamboo-like sections along the [0 0 2] direction during a progressive pulse-controlled electrochemical growth of NW arrays under optimized parameters. Our results both provide new insights into the growth process, crystalline characteristics and magnetic phases along the length of large diameter NW arrays and, furthermore, develop the performance of pure 3d transition magnetic NWs.

  18. Diameter effect on critical heat flux

    International Nuclear Information System (INIS)

    Tanase, A.; Cheng, S.C.; Groeneveld, D.C.; Shan, J.Q.

    2009-01-01

    The critical heat flux look-up table (CHF LUT) is widely used to predict CHF for various applications, including design and safety analysis of nuclear reactors. Using the CHF LUT for round tubes having inside diameters different from the reference 8 mm involves conversion of CHF to 8 mm. Different authors [Becker, K.M., 1965. An Analytical and Experimental Study of Burnout Conditions in Vertical Round Ducts, Aktiebolaget Atomenergie Report AE 177, Sweden; Boltenko, E.A., et al., 1989. Effect of tube diameter on CHF at various two phase flow regimes, Report IPE-1989; Biasi, L., Clerici, G.C., Garriba, S., Sala, R., Tozzi, A., 1967. Studies on Burnout, Part 3, Energia Nucleare, vol. 14, pp. 530-536; Groeneveld, D.C., Cheng, S.C., Doan, T., 1986. AECL-UO critical heat flux look-up table. Heat Transfer Eng., 7, 46-62; Groeneveld et al., 1996; Hall, D.D., Mudawar, I., 2000. Critical heat flux for water flow in tubes - II subcooled CHF correlations. Int. J. Heat Mass Transfer, 43, 2605-2640; Wong, W.C., 1996. Effect of tube diameter on critical heat flux, MaSC dissertation, Ottawa Carleton Institute for Mechanical and Aeronautical Engineering, University of Ottawa] have proposed several types of correlations or factors to describe the diameter effect on CHF. The present work describes the derivation of new diameter correction factor and compares it with several existing prediction methods

  19. Diameter Tuning of β-Ga2O3 Nanowires Using Chemical Vapor Deposition Technique.

    Science.gov (United States)

    Kumar, Mukesh; Kumar, Vikram; Singh, R

    2017-12-01

    Diameter tuning of [Formula: see text]-Ga 2 O 3 nanowires using chemical vapor deposition technique have been investigated under various experimental conditions. Diameter of root grown [Formula: see text]-Ga 2 O 3 nanowires having monoclinic crystal structure is tuned by varying separation distance between metal source and substrate. Effect of gas flow rate and mixer ratio on the morphology and diameter of nanowires has been studied. Nanowire diameter depends on growth temperature, and it is independent of catalyst nanoparticle size at higher growth temperature (850-900 °C) as compared to lower growth temperature (800 °C). These nanowires show changes in structural strain value with change in diameter. Band-gap of nanowires increases with decrease in the diameter.

  20. Study of thermal and hydraulic efficiency of supersonic tube of temperature stratification

    Science.gov (United States)

    Tsynaeva, Anna A.; Nikitin, Maxim N.; Tsynaeva, Ekaterina A.

    2017-10-01

    Efficiency of supersonic pipe for temperature stratification with finned subsonic surface of heat transfer is the major of this paper. Thermal and hydraulic analyses of this pipe were conducted to asses effects from installation of longitudinal rectangular and parabolic fins as well as studs of cylindrical, rectangular and parabolic profiles. The analysis was performed based on refined empirical equations of similarity, dedicated to heat transfer of high-speed gas flow with plain wall, and Kármán equation with Nikuradze constants. Results revealed cylindrical studs (with height-to-diameter ratio of 5:1) to be 1.5 times more efficient than rectangular fins of the same height. At the same time rectangular fins (with height-to-thickness ratio of 5:1) were tend to enhance heat transfer rate up to 2.67 times compared to bare walls from subsonic side of the pipe. Longitudinal parabolic fins have minuscule effect on combined efficiency of considered pipe since extra head losses void any gain of heat transfer. Obtained results provide perspective of increasing efficiency of supersonic tube for temperature stratification. This significantly broadens device applicability in thermostatting systems for equipment, cooling systems for energy converting machinery, turbine blades and aerotechnics.

  1. Measuring Electrospun Nanofibre Diameter: a Novel Approach

    International Nuclear Information System (INIS)

    Ziabari, M.; Mottaghitalab, V.; Haghi, A. K.; McGovern, S. T.

    2008-01-01

    A new method based on image analysis for electrospun nanofibre diameter measurement is presented. First, the SEM micrograph of the nanofibre web obtained by electrospinning process is converted to binary image using local thresholding method. In the next step, skeleton and distance transformed image are generated. Then, the intersection points which bring about untrue measurements are identified and removed from the skeleton. Finally, the resulting skeleton and distance transformed image are used to determine fibre diameter. The method is evaluated by a simulated image with known characteristics generated by ?-randomness procedure. The results indicate that this approach is successful in making fast, accurate automated measurements of electrospun fibre diameters. (cross-disciplinary physics and related areas of science and technology)

  2. Hydraulic gradients in rock aquifers

    International Nuclear Information System (INIS)

    Dahlblom, P.

    1992-05-01

    This report deals with fractured rock as a host for deposits of hazardous waste. In this context the rock, with its fractures containing moving groundwater, is called the geological barrier. The desired properties of the geological barrier are low permeability to water, low hydraulic gradients and ability to retain matter dissolved in the water. The hydraulic gradient together with the permeability and the porosity determines the migration velocity. Mathematical modelling of the migration involves calculation of the water flow and the hydrodynamic dispersion of the contaminant. The porous medium approach can be used to calculate mean flow velocities and hydrodynamic dispersion of a large number of fractures are connected, which means that a large volume have to be considered. It is assumed that the porous medium approach can be applied, and a number of idealized examples are shown. It is assumed that the groundwater table is replenished by percolation at a constant rate. One-dimensional analytical calculations show that zero hydraulic gradients may exist at relatively large distance from the coast. Two-dimensional numerical calculations show that it may be possible to find areas with low hydraulic gradients and flow velocities within blocks surrounded by areas with high hydraulic conductivity. (au)

  3. Inherent Limitations of Hydraulic Tomography

    Science.gov (United States)

    Bohling, Geoffrey C.; Butler, J.J.

    2010-01-01

    We offer a cautionary note in response to an increasing level of enthusiasm regarding high-resolution aquifer characterization with hydraulic tomography. We use synthetic examples based on two recent field experiments to demonstrate that a high degree of nonuniqueness remains in estimates of hydraulic parameter fields even when those estimates are based on simultaneous analysis of a number of carefully controlled hydraulic tests. We must, therefore, be careful not to oversell the technique to the community of practicing hydrogeologists, promising a degree of accuracy and resolution that, in many settings, will remain unattainable, regardless of the amount of effort invested in the field investigation. No practically feasible amount of hydraulic tomography data will ever remove the need to regularize or bias the inverse problem in some fashion in order to obtain a unique solution. Thus, along with improving the resolution of hydraulic tomography techniques, we must also strive to couple those techniques with procedures for experimental design and uncertainty assessment and with other more cost-effective field methods, such as geophysical surveying and, in unconsolidated formations, direct-push profiling, in order to develop methods for subsurface characterization with the resolution and accuracy needed for practical field applications. Copyright ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  4. Selective perceptions of hydraulic fracturing.

    Science.gov (United States)

    Sarge, Melanie A; VanDyke, Matthew S; King, Andy J; White, Shawna R

    2015-01-01

    Hydraulic fracturing (HF) is a focal topic in discussions about domestic energy production, yet the American public is largely unfamiliar and undecided about the practice. This study sheds light on how individuals may come to understand hydraulic fracturing as this unconventional production technology becomes more prominent in the United States. For the study, a thorough search of HF photographs was performed, and a systematic evaluation of 40 images using an online experimental design involving N = 250 participants was conducted. Key indicators of hydraulic fracturing support and beliefs were identified. Participants showed diversity in their support for the practice, with 47 percent expressing low support, 22 percent high support, and 31 percent undecided. Support for HF was positively associated with beliefs that hydraulic fracturing is primarily an economic issue and negatively associated with beliefs that it is an environmental issue. Level of support was also investigated as a perceptual filter that facilitates biased issue perceptions and affective evaluations of economic benefit and environmental cost frames presented in visual content of hydraulic fracturing. Results suggested an interactive relationship between visual framing and level of support, pointing to a substantial barrier to common understanding about the issue that strategic communicators should consider.

  5. Birth of a hydraulic jump

    Science.gov (United States)

    Duchesne, Alexis; Bohr, Tomas; Andersen, Anders

    2017-11-01

    The hydraulic jump, i.e., the sharp transition between a supercritical and a subcritical free-surface flow, has been extensively studied in the past centuries. However, ever since Leonardo da Vinci asked it for the first time, an important question has been left unanswered: How does a hydraulic jump form? We present an experimental and theoretical study of the formation of stationary hydraulic jumps in centimeter wide channels. Two starting situations are considered: The channel is, respectively, empty or filled with liquid, the liquid level being fixed by the wetting properties and the boundary conditions. We then change the flow-rate abruptly from zero to a constant value. In an empty channel, we observe the formation of a stationary hydraulic jump in a two-stage process: First, the channel fills by the advancing liquid front, which undergoes a transition from supercritical to subcritical at some position in the channel. Later the influence of the downstream boundary conditions makes the jump move slowly upstream to its final position. In the pre-filled channel, the hydraulic jump forms at the injector edge and then moves downstream to its final position.

  6. Thermal-hydraulic modeling of porous bed reactors

    International Nuclear Information System (INIS)

    Araj, K.J.; Nourbakhsh, H.P.

    1987-01-01

    Optimum design of nuclear reactor core requires an iterative approach between the thermal-hydraulic, neutronic and operational analysis. This paper concentrates on the thermal-hydraulic behavior of a hydrogen cooled, small particle bed reactor (PBR). The PBR core, modeled here, consists of a hexagonal array of fuel elements embedded in a moderator matrix. The fuel elements are annular packed beds of fuel particles held between two porous cylindrical frits. These particles, 500 to 600 μm in diameter, have a uranium carbide core, which is coated by two layers of graphite and an outer coating of zirconium carbide. Coolant flow, radially inward, from the cold frit through the packed bed and hot frit and axially out the channel, formed by the hot frit, to a common plenum. 5 refs., 1 fig., 2 tabs

  7. Moisture monitoring in large diameter boreholes

    International Nuclear Information System (INIS)

    Tyler, S.

    1985-01-01

    The results of both laboratory and field experiments indicate that the neutron moisture gauge traditionally used in soil physics experiments can be extended for use in large diameter (up to 15 cm) steel-cased boreholes with excellent results. This application will permit existing saturated zone monitoring wells to be used for unsaturated zone monitoring of recharge, redistribution and leak detection from waste disposal facilities. Its applicability to large diameter cased wells also gives the soil physicist and ground-water hydrologist and new set of monitoring points in the unsaturated zone to study recharge and aquifer properties. 6 refs., 6 figs., 2 tabs

  8. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.

    2013-02-01

    Biofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness

  9. Effect of Aspect Ratio, Channel Orientation, Rib Pitch-to-Height Ratio, and Number of Ribbed Walls on Pressure Drop Characteristics in a Rotating Channel with Detached Ribs

    Directory of Open Access Journals (Sweden)

    K. Arun

    2007-01-01

    Full Text Available The present work involves experimental investigation of the effects of aspect ratio, channel orientation angle, rib pitch-to-height ratio (P/e, and number of ribbed walls on friction factor in orthogonally rotating channel with detached ribs. The ribs are separated from the base wall to provide a small region of flow between the base wall and the ribs. Experiments have been conducted at Reynolds number ranging from 10000–17000 with rotation numbers varying from 0–0.38. Pitch-to-rib height ratios (P/e of 5 and 10 at constant rib height-to-hydraulic diameter ratio (e/D of 0.1 and a clearance ratio (C/e of 0.38 are considered. The rib angle of attack with respect to mainstream flow is 90∘. The channel orientation at which the ribbed wall becomes trailing surface (pressure side on which the Coriolis force acts is considered as the 0∘ orientation angle. For one-wall ribbed case, channel is oriented from 0∘ to 180∘ about its axis in steps of 30∘ to change the orientation angle. For two-wall ribbed case, the orientation angle is changed from 0∘ to 90∘ in steps of 30∘. Friction factors for the detached ribbed channels are compared with the corresponding attached ribbed channel. It is found that in one-wall detached ribbed channel, increase in the friction factor ratio with the orientation angle is lower for rectangular channel compared to that of square channel for both the pitch-to-rib height ratios of 5 and 10 at a given Reynolds number and rotation number. Friction factor ratios of two-wall detached ribbed rectangular channel are comparable with corresponding two-wall detached ribbed square channel both under stationary and rotating conditions.

  10. Experimental Study about Two-phase Damping Ratio on a Tube Bundle Subjected to Homogeneous Two-phase Flow

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Woo Gun; Dagdan, Banzragch [Hannam Univ., Daejeon (Korea, Republic of)

    2017-03-15

    Two-phase cross flow exists in many shell-and-tube heat exchangers such as condensers, evaporators, and nuclear steam generators. The drag force acting on a tube bundle subjected to air/water flow is evaluated experimentally. The cylinders subjected to two-phase flow are arranged in a normal square array. The ratio of pitch to diameter is 1.35, and the diameter of the cylinder is 18 mm. The drag force along the flow direction on the tube bundles is measured to calculate the drag coefficient and the two-phase damping ratio. The two-phase damping ratios, given by the analytical model for a homogeneous two-phase flow, are compared with experimental results. The correlation factor between the frictional pressure drop and the hydraulic drag coefficient is determined from the experimental results. The factor is used to calculate the drag force analytically. It is found that with an increase in the mass flux, the drag force, and the drag coefficients are close to the results given by the homogeneous model. The result shows that the damping ratio can be calculated using the homogeneous model for bubbly flow of sufficiently large mass flux.

  11. Advantages of Oscillatory Hydraulic Tomography

    Science.gov (United States)

    Kitanidis, P. K.; Bakhos, T.; Cardiff, M. A.; Barrash, W.

    2012-12-01

    Characterizing the subsurface is significant for most hydrogeologic studies, such as those involving site remediation and groundwater resource explo¬ration. A variety of hydraulic and geophysical methods have been developed to estimate hydraulic conductivity and specific storage. Hydraulic methods based on the analysis of conventional pumping tests allow the estimation of conductivity and storage without need for approximate petrophysical relations, which is an advantage over most geophysical methods that first estimate other properties and then infer values of hydraulic parameters. However, hydraulic methods have the disadvantage that the head-change signal decays with distance from the pumping well and thus becomes difficult to separate from noise except in close proximity to the source. Oscillatory hydraulic tomography (OHT) is an emerging technology to im¬age the subsurface. This method utilizes the idea of imposing sinusoidally varying pressure or discharge signals at several points, collecting head observations at several other points, and then processing these data in a tomographic fashion to estimate conductivity and storage coefficients. After an overview of the methodology, including a description of the most important potential advantages and challenges associated with this approach, two key promising features of the approach will be discussed. First, the signal at an observation point is orthogonal to and thus can be separated from nuisance inputs like head fluctuation from production wells, evapotranspiration, irrigation, and changes in the level of adjacent streams. Second, although the signal amplitude may be weak, one can extract the phase and amplitude of the os¬cillatory signal by collecting measurements over a longer time, thus compensating for the effect of large distance through longer sampling period.

  12. Small diameter symmetric networks from linear groups

    Science.gov (United States)

    Campbell, Lowell; Carlsson, Gunnar E.; Dinneen, Michael J.; Faber, Vance; Fellows, Michael R.; Langston, Michael A.; Moore, James W.; Multihaupt, Andrew P.; Sexton, Harlan B.

    1992-01-01

    In this note is reported a collection of constructions of symmetric networks that provide the largest known values for the number of nodes that can be placed in a network of a given degree and diameter. Some of the constructions are in the range of current potential engineering significance. The constructions are Cayley graphs of linear groups obtained by experimental computation.

  13. Changing the Diameter of a Viewing Tube

    Science.gov (United States)

    Obara, Samuel

    2009-01-01

    This article is about the students' investigation about the relationship between the diameter of the view tubes (x) of constant lengths and the viewable vertical distance (y) on the wall while keeping the perpendicular distance from the eyeball to the wall constant. The students collected data and used and represented it in tabular and graphical…

  14. Height - Diameter predictive equations for Rubber (Hevea ...

    African Journals Online (AJOL)

    BUKOLA

    They proffer logistic data for modeling and futuristic prediction for sustainable forest management. Diameter is one of the most ... in various quantitative estimation following the intricacy of time, availability of modern equipments .... growth functions. This trend is shown in Figure 1 where the prediction equations are plotted.

  15. Water hydraulic applications in hazardous environments

    International Nuclear Information System (INIS)

    Siuko, M.; Koskinen, K.T.; Vilenius, M.J.

    1996-01-01

    Water hydraulic technology provides several advantages for devices operating in critical environment. Though water hydraulics has traditionally been used in very rough applications, gives recent strong development of components possibility to build more sophisticated applications and devices with similar capacity and control properties than those of oil hydraulics without the disadvantages of oil hydraulic systems. In this paper, the basic principles, possibilities and advantages of water hydraulics are highlighted, some of the most important design considerations are presented and recent developments of water hydraulic technology are presented. Also one interesting application area, ITER fusion reactor remote handling devices, are discussed. (Author)

  16. Hydraulic lifter for an underwater drilling rig

    Energy Technology Data Exchange (ETDEWEB)

    Garan' ko, Yu L

    1981-01-15

    A hydraulic lifter is suggested for an underwater drilling rig. It includes a base, hydraulic cylinders for lifting the drilling pipes connected to the clamp holder and hydraulic distributor. In order to simplify the design of the device, the base is made with a hollow chamber connected to the rod cavities and through the hydraulic distributor to the cavities of the hydraulic cylinders for lifting the drilling pipes. The hydraulic distributor is connected to the hydrosphere through the supply valve with control in time or by remote control. The base is equipped with reverse valves whose outlets are on the support surface of the base.

  17. Hydraulic lifter of a drilling unit

    Energy Technology Data Exchange (ETDEWEB)

    Velikovskiy, L S; Demin, A V; Shadchinov, L M

    1979-01-08

    The invention refers to drilling equipment, in particular, devices for lowering and lifting operations during drilling. A hydraulic lifter of the drilling unit is suggested which contains a hydraulic cylinder, pressure line and hollow plunger whose cavities are hydraulically connected. In order to improve the reliability of the hydraulic lifter by balancing the forces of compression in the plunger of the hydraulic cylinder, a closed vessel is installed inside the plunger and rigidly connected to its ends. Its cavity is hydraulically connected to the pressure line.

  18. Controls of Hydraulic Wind Turbine

    Directory of Open Access Journals (Sweden)

    Zhang Yin

    2016-01-01

    Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

  19. Thermal hydraulic design of PFBR core

    International Nuclear Information System (INIS)

    Roychowdhury, D.G.; Vinayagam, P.P.; Ravichandar, S.C.

    2000-01-01

    The thermal-hydraulic design of core is important in respecting temperature limits while achieving higher outlet temperature. This paper deals with the analytical process developed and implemented for analysing steady state thermal-hydraulics of PFBR core. A computer code FLONE has been developed for optimisation of flow allocation through the subassemblies (SA). By calibrating β n (ratio between the maximum channel temperature rise and SA average temperature rise) values with SUPERENERGY code and using these values in FLONE code, prediction of average and maximum coolant temperature distribution is found to be reasonably accurate. Hence, FLONE code is very powerful design tool for core design. A computer code SAPD has been developed to calculate the pressure drop of fuel and blanket SA. Selection of spacer wire pitch depends on the pressure drop, flow-induced vibration and the mixing characteristics. A parametric study was made for optimisation of spacer wire pitch for the fuel SA. Experimental programme with 19 pin-bundle has been undertaken to find the flow-induced vibration characteristics of fuel SA. Also, experimental programme has been undertaken on a full-scale model to find the pressure drop characteristics in unorificed SA, orifices and the lifting force on the SA. (author)

  20. The effect of hydraulic bed movement on the quality of chest compressions.

    Science.gov (United States)

    Park, Maeng Real; Lee, Dae Sup; In Kim, Yong; Ryu, Ji Ho; Cho, Young Mo; Kim, Hyung Bin; Yeom, Seok Ran; Min, Mun Ki

    2017-08-01

    The hydraulic height control systems of hospital beds provide convenience and shock absorption. However, movements in a hydraulic bed may reduce the effectiveness of chest compressions. This study investigated the effects of hydraulic bed movement on chest compressions. Twenty-eight participants were recruited for this study. All participants performed chest compressions for 2min on a manikin and three surfaces: the floor (Day 1), a firm plywood bed (Day 2), and a hydraulic bed (Day 3). We considered 28 participants of Day 1 as control and each 28 participants of Day 2 and Day 3 as study subjects. The compression rates, depths, and good compression ratios (>5-cm compressions/all compressions) were compared between the three surfaces. When we compared the three surfaces, we did not detect a significant difference in the speed of chest compressions (p=0.582). However, significantly lower values were observed on the hydraulic bed in terms of compression depth (p=0.001) and the good compression ratio (p=0.003) compared to floor compressions. When we compared the plywood and hydraulic beds, we did not detect significant differences in compression depth (p=0.351) and the good compression ratio (p=0.391). These results indicate that the movements in our hydraulic bed were associated with a non-statistically significant trend towards lower-quality chest compressions. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. The effect of polyploidization on tree hydraulic functioning.

    Science.gov (United States)

    De Baerdemaeker, Niels J F; Hias, Niek; Van den Bulcke, Jan; Keulemans, Wannes; Steppe, Kathy

    2018-02-01

    Recent research has highlighted the importance of living tissue in wood. Polyploidization can impact amounts and arrangements of living cells in wood, potentially leading to increased drought tolerance. Tetraploid variants were created from the apple cultivar Malus ×domestica 'Gala' (Gala-4x), and their vulnerability to drought-induced cavitation and their hydraulic capacitance were compared to those of their diploid predecessors (Gala-2x). Assuming a positive correlation between polyploidy and drought tolerance, we hypothesized lower vulnerability and higher capacitance for the tetraploid. Vulnerability to drought-induced cavitation and the hydraulic capacitance were quantified through acoustic emission and continuous weighing of shoots during a bench-top dehydration experiment. To underpin the hydraulic trait results, anatomical variables such as vessel area, conduit diameter, cell wall reinforcement, and ray and vessel-associated parenchyma were measured. Vulnerability to drought-induced cavitation was intrinsically equal for both ploidy variants, but Gala-4x proved to be more vulnerable than Gala-2x during the early phase of desiccation as was indicated by its significantly lower air entry value. Higher change in water content of the leafy shoot, higher amount of parenchyma, and larger vessel area and size resulted in a significantly higher hydraulic capacitance and efficiency for Gala-4x compared to Gala-2x. Both ploidy variants were typified as highly sensitive to drought-induced cavitation, with no significant difference in their overall drought vulnerability. But, when water deficit is short and moderate, Gala-4x may delay a drought-induced decrease in performance by trading hydraulic safety for increased release of capacitively stored water from living tissue. © 2018 Botanical Society of America.

  2. Influence of Drought on the Hydraulic Efficiency and the Hydraulic Safety of the Xylem - Case of a Semi-arid Conifer.

    Science.gov (United States)

    Gentine, P.; Guerin, M. F.; von Arx, G.; Martin-Benito, D.; Griffin, K. L.; McDowell, N.; Pockman, W.; Andreu-Hayles, L.

    2017-12-01

    Recent droughts in the Southwest US have resulted in extensive mortality in the pinion pine population (Pinus Edulis). An important factor for resiliency is the ability of a plant to maintain a functional continuum between soil and leaves, allowing water's motion to be sustained or resumed. During droughts, loss of functional tracheids happens through embolism, which can be partially mitigated by increasing the hydraulic safety of the xylem. However, higher hydraulic safety is usually achieved by building narrower tracheids with thicker walls, resulting in a reduction of the hydraulic efficiency of the xylem (conductivity per unit area). Reduced efficiency constrains water transport, limits photosynthesis and might delay recovery after the drought. Supporting existing research on safety-efficiency tradeoff, we test the hypothesis that under dry conditions, isohydric pinions grow xylem that favor efficiency over safety. Using a seven-year experiment with three watering treatments (drought, control, irrigated) in New Mexico, we investigate the effect of drought on the xylem anatomy of pinions' branches. We also compare the treatment effect with interannual variations in xylem structure. We measure anatomical variables - conductivities, cell wall thicknesses, hydraulic diameter, cell reinforcement and density - and preliminarily conclude that treatment has little effect on hydraulic efficiency while hydraulic safety is significantly reduced under dry conditions. Taking advantage of an extremely dry year occurrence during the experiment, we find a sharp increase in vulnerability for xylem tissues built the same year.

  3. Tree diameter at breast height in relation to stump diameter by species group

    Science.gov (United States)

    Arthur G. Horn; Richard C. Keller

    1957-01-01

    A stump tally is one method of determining the volume of timber previously removed from an area in a logging operation. To estimate volume of standing timber from stumps, foresters must first know the relationship between stump diameters and tree diameters at breast height (d.b.h.).

  4. Theoretical study of hydraulic jump during circular horizontal hot leg injection in pressurized water reactor

    International Nuclear Information System (INIS)

    El Hawary, Shehab; Abu-Elyazeed, Osayed S.M.; Fahmy, Adel Alyan; Meglaa, Khairy

    2016-01-01

    Highlights: • The model is developed to predict the occurrence of onset hydraulic jump in a circular pipe. • Theoretical results are in agreement with experimental results and theory. • Effects of diameter of the injection pipe, Froude number and injected coolant mass are studied. - Abstract: One important phenomenon occurring during Loss of Coolant Accident (LOCA) is Counter-Current Flow Limitation (CCFL). The incidence of such CCFL is introduced by the onset of hydraulic jump. In the present work, a one dimensional model was modified to fit circular hot channel. The model was used to study the factors affecting the initial Froude number, the location of the occurrence of the hydraulic jump, and the critical coolant flow depth during circular horizontal hot leg injection in US-APWR Mitsubishi Reactor. The results showed good agreement with published experimental data of the Upper Plenum Test Facility (UPTF) at Mannheim, Germany. It was found that higher injected coolant mass flow rate increases the initial Froude number, the location of the occurrence of the hydraulic jump, and the critical injection depth divided by the diameter of the injection pipe. Such behavior is thought to be due to the increase of the inertia force by increasing of the injected coolant mass flow rate and the inverse of the diameter of the injection pipe. It was found also that, the location of the occurrence of hydraulic jump increases with decreasing load effect. Therefore, these results reveal that the avoidance of CCFL as well as hydraulic jump through hot leg at maximum load can be achieved by decreasing the distance between the injection point and the pressure vessel to below 0.3 m, and with diameter of 4 in (10.16 cm) as the design diameter of the injection pipe in US-APWR Mitsubishi Reactor. Moreover, the maximum critical depth (56 cm) is less than the diameter of the hot leg (78.74 cm) at an injected coolant mass flow of 400 kg/s, and with diameter of 4 in (10.16 cm) as the

  5. Does initial spacing influence crown and hydraulic architecture of Eucalyptus marginata?

    Science.gov (United States)

    Grigg, A H; Macfarlane, C; Evangelista, C; Eamus, D; Adams, M A

    2008-05-01

    Long-term declines in rainfall in south-western Australia have resulted in increased interest in the hydraulic characteristics of jarrah (Eucalyptus marginata Donn ex Smith) forest established in the region's drinking water catchments on rehabilitated bauxite mining sites. We hypothesized that in jarrah forest established on rehabilitated mine sites: (1) leaf area index (L) is independent of initial tree spacing; and (2) more densely planted trees have less leaf area for the same leaf mass, or the same sapwood area, and have denser sapwood. Initial stand densities ranged from about 600 to 9000 stems ha(-1), and trees were 18 years old at the time of sampling. Leaf area index was unaffected by initial stand density, except in the most sparsely stocked stands where L was 1.2 compared with 2.0-2.5 in stands at other spacings. The ratio of leaf area to sapwood area (A(l):A(s)) was unaffected by tree spacing or tree size and was 0.2 at 1.3 m height and 0.25 at the crown base. There were small increases in sapwood density and decreases in leaf specific area with increased spacing. Tree diameter or basal area was a better predictor of leaf area than sapwood area. At the stand scale, basal area was a good predictor of L (r(2) = 0.98, n = 15) except in the densest stands. We conclude that the hydraulic attributes of this forest type are largely independent of initial tree spacing, thus simplifying parameterization of stand and catchment water balance models.

  6. Design of hydraulic recuperation unit

    Directory of Open Access Journals (Sweden)

    Jandourek Pavel

    2016-01-01

    Full Text Available This article deals with design and measurement of hydraulic recuperation unit. Recuperation unit consist of radial turbine and axial pump, which are coupled on the same shaft. Speed of shaft with impellers are 6000 1/min. For economic reasons, is design of recuperation unit performed using commercially manufactured propellers.

  7. Tree Hydraulics: How Sap Rises

    Science.gov (United States)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  8. Tubing Cutter is Activated Hydraulically

    Science.gov (United States)

    Mcsmith, D. G.; Richardson, J. I.

    1983-01-01

    Hydraulically-actuated tubing cutter severs tubing when operator squeezes handle grip. "Gooseneck" extension enables cutter to be used in areas where accessiblity is limited. Cutter has potential as flight-line tool and is useful in automobile and fire rescue work.

  9. Hydraulics calculation in drilling simulator

    Science.gov (United States)

    Malyugin, Aleksey A.; Kazunin, Dmitry V.

    2018-05-01

    The modeling of drilling hydraulics in the simulator system is discussed. This model is based on the previously developed quasi-steady model of an incompressible fluid flow. The model simulates the operation of all parts of the hydraulic drilling system. Based on the principles of creating a common hydraulic model, a set of new elements for well hydraulics was developed. It includes elements that correspond to the in-drillstring and annular space. There are elements controlling the inflow from the reservoir into the well and simulating the lift of gas along the annulus. New elements of the hydrosystem take into account the changing geometry of the well, loss in the bit, characteristics of the fluids including viscoplasticity. There is an opportunity specify the complications, the main one of which is gas, oil and water inflow. Correct work of models in cases of complications makes it possible to work out various methods for their elimination. The coefficients of the model are adjusted on the basis of incomplete experimental data provided by operators of drilling platforms. At the end of the article the results of modeling the elimination of gas inflow by a continuous method are presented. The values displayed in the simulator (drill pipe pressure, annulus pressure, input and output flow rates) are in good agreement with the experimental data. This exercise took one hour, which is less than the time on a real rig with the same configuration of equipment and well.

  10. Hydraulics submission for Middlesex County, NJ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data include spatial datasets and data tables necessary for documenting the hydraulic procedures for estimating base flood elevation for a flood insurance...

  11. DCS Hydraulics Submittal, Bullock County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  12. DCS Hydraulics Submittal, Butler County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  13. DCS Hydraulics Submittal, Covington County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  14. CRITICALITY CURVES FOR PLUTONIUM HYDRAULIC FLUID MIXTURES

    International Nuclear Information System (INIS)

    WITTEKIND WD

    2007-01-01

    This Calculation Note performs and documents MCNP criticality calculations for plutonium (100% 239 Pu) hydraulic fluid mixtures. Spherical geometry was used for these generalized criticality safety calculations and three geometries of neutron reflection are: (sm b ullet)bare, (sm b ullet)1 inch of hydraulic fluid, or (sm b ullet)12 inches of hydraulic fluid. This document shows the critical volume and critical mass for various concentrations of plutonium in hydraulic fluid. Between 1 and 2 gallons of hydraulic fluid were discovered in the bottom of HA-23S. This HA-23S hydraulic fluid was reported by engineering to be Fyrquel 220. The hydraulic fluid in GLovebox HA-23S is Fyrquel 220 which contains phosphorus. Critical spherical geometry in air is calculated with 0 in., 1 in., or 12 inches hydraulic fluid reflection

  15. Hydraulics submission for Gloucester County, NJ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data include spatial datasets and data tables necessary for documenting the hydraulic procedures for estimating base flood elevation for a flood insurance...

  16. A comparison of the CHF between tubes and annuli under PWR thermal-hydraulic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Herer, C. [RRAMATOME EP/TC, Paris (France); Souyri, A. [EdF DER/RNE/TTA, Chatou (France); Garnier, J. [CEA DRN/DTP/STR/LETC, Grenoble (France)

    1995-09-01

    Critical Heat Flux (CHF) tests were carried out in three tubes with inside diameters of 8, 13, and 19.2 mm and in two annuli with an inner tube of 9.5 mm and an outer tube of 13 or 19.2 mm. All axial heat flux distributions in the test sections were uniform. The coolant fluid was Refrigerant 12 (Freon-12) under PWR thermal-hydraulic conditions (equivalent water conditions - Pressure: 7 to 20 MPa, Mass Velocity: 1000 to 6000 kg/m2/s, Local Quality: -75% to +45%). The effect of tube diameter is correlated for qualities under 15%. The change from the tube to the annulus configuration is correctly taken into account by the equivalent hydraulic diameter. Useful information is also provided concerning the effect of a cold wall in an annulus.

  17. Hydraulic characterization of " Furcraea andina

    Science.gov (United States)

    Rivera-Velasquez, M. F.; Fallico, C.; Molinari, A.; Santillan, P.; Salazar, M.

    2012-04-01

    The present level of pollution, increasingly involving groundwaters, constitutes a serious risk for environment and human health. Therefore the remediation of saturated and unsaturated soils, removing pollutant materials through innovative and economic bio-remediation techniques is more frequently required. Recent studies on natural fiber development have shown the effectiveness of these fibers for removal of some heavy metals, due to the lignin content in the natural fibers which plays an important role in the adsorption of metal cations (Lee et al., 2004; Troisi et al., 2008; C. Fallico, 2010). In the context of remediation techniques for unsaturated and/or saturated zone, an experimental approach for the hydraulic characterization of the "Furcraea andina" (i.e., Cabuya Blanca) fiber was carried out. This fiber is native to Andean regions and grows easily in wild or cultivated form in the valleys and hillsides of Colombia, Ecuador, and Peru. Fibers of "Furcraea andina" were characterized by experimental tests to determine their hydraulic conductivity or permeability and porosity in order to use this medium for bioremediation of contaminated aquifer exploiting the physical, chemical and microbial capacity of natural fiber in heavy metal adsorption. To evaluate empirically the hydraulic conductivity, laboratory tests were carried out at constant head specifically on the fibers manually extracted. For these tests we used a flow cell (used as permeameter), containing the "Furcraea andina" fibers to be characterized, suitably connected by a tygon pipe to a Marriott's bottle, which had a plastic tube that allow the adjustment of the hydraulic head for different tests to a constant value. By this experiment it was also possible to identify relationships that enable the estimation of permeability as a function of density, i.e. of the compaction degree of the fibers. Our study was carried out for three values of hydraulic head (H), namely 10, 18, and 25 cm and for each

  18. HYDRAULIC ELEVATOR INSTALLATION ESTIMATION FOR THE WATER SOURCE WELL SAND-PACK CLEANING UP

    Directory of Open Access Journals (Sweden)

    V. V. Ivashechkin

    2016-01-01

    Full Text Available The article offers design of a hydraulic elevator installation for cleaning up water-source wells of sand packs. It considerers the installation hydraulic circuit according to which the normal pump feeds the high-level tank water into the borehole through two parallel water lines. The water-jet line with washing nozzle for destroying the sand-pack and the supply pipe-line coupled with the operational nozzle of the hydraulic elevator containing the inlet and the supply pipelines for respectively intaking the hydromixture and removing it from the well. The paper adduces equations for fluid motion in the supply and the water-jet pipelines and offers expressions for evaluating the required heads in them. For determining water flow in the supply and the water-jet pipe lines the author proposes to employ graphical approach allowing finding the regime point in Q–H chart by means of building characteristics of the pump and the pipe-lines. For calculating the useful vertical head, supply and dimensions of the hydraulic elevator the article employs the equation of motion quantity with consistency admission of the motion quantity before and after mixing the flows in the hydraulic elevator. The suggested correlations for evaluating the hydraulic elevator efficiency determine the sand pack removal duration as function of its sizes and the ejected fluid flow rate. A hydraulic-elevator installation parameters estimation example illustrates removing a sand pack from a water-source borehole of 41 m deep and 150 mm diameter bored in the village of Uzla of Myadelsk region, of Minsk oblast. The working efficiency of a manufactured and laboratory tested engineering prototype of the hydraulic elevator installation was acknowledged in actual tests at the indicated borehole site. With application of graphical approach, the suggested for the hydraulic elevator installation parameters calculation procedure allows selecting, with given depth and the borehole diameter

  19. Carotid flow velocity/diameter ratio is a predictor of cardiovascular events in hypertensive patients

    DEFF Research Database (Denmark)

    Bellinazzi, Vera R; Cipolli, José A; Pimenta, Marcio V

    2015-01-01

    AD) greater than the median value presented the worst clinical outcome compared to those with isolated sFV less than the median value or sAD greater than the median value, suggesting an additive effect of these two variables. Further, Kaplan-Meier analysis demonstrated worse outcome for individuals with s...... intima-media thickness and clinically defined high cardiovascular risk did not. Furthermore, area under the receiver-operating characteristic curve for sFV/sAD was higher than that for Framingham risk score (0.77 versus 0.64; P = 0.045), whereas adding sFV/sAD to the Framingham risk factors resulted...

  20. Device for guiding various diameter size cable

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, I.M.; Klauzer, L.P.; Yeganov, L.I.; Zaripov, A.M.

    1982-01-30

    A design is submitted for a device to guide cable of various diameters. This device consists of a profiled multiple-pass roller, and clamps for uniting cut cable. This design is simplified by allowing both the rollers and their supports to rotate on the roller axis thus facilitating interaction with the clamps. The working surface of the supports is evolute while the outside surfaces have screw-channels for transfering the cable from one roller pass to the other.

  1. Subsea Hydraulic Leakage Detection and Diagnosis

    OpenAIRE

    Stavenes, Thomas

    2010-01-01

    The motivation for this thesis is reduction of hydraulic emissions, minimizing of process emergency shutdowns, exploitation of intervention capacity, and reduction of costs. Today, monitoring of hydraulic leakages is scarce and the main way to detect leakage is the constant need for filling of hydraulic fluid to the Hydraulic Power Unit (HPU). Leakage detection and diagnosis has potential, which would be adressed in this thesis. A strategy towards leakage detection and diagnosis is given....

  2. Parameters Analysis of Hydraulic-Electrical Energy Regenerative Absorber on Suspension Performance

    Directory of Open Access Journals (Sweden)

    Han Zhang

    2014-05-01

    Full Text Available To recycle the vibration energy of vehicles over rough roads, a hydraulic-electricity energy regenerative suspension (HEERS was designed in the present work, and simulations were performed with focus on its performance. On the basis of the system principle, the mathematical model of hydraulic-electrical energy regenerative absorber (HEERA and two degrees of freedom (DOF suspension dynamic model were constructed. Using the model of HEERA, simulations on force-displacement and force-velocity characteristics were performed with a 1.67 Hz frequency and a sinusoidal input adopted. And then in combination with HEERA model and two DOF suspension models, simulations on the performance of HEERS also were carried out. Finally, the influences of charging pressure and volume of the accumulator, hydraulic motor displacement, orifice area of check valve, and inner diameter of hydraulic pipelines on the performance of HEERA and HEERS were investigated in depth. The simulation results indicated that (i the damping characteristic of HEERA was coincident with the damping characteristics of traditional absorber; (ii the most remarkable influencing factor on the performance of HEERS was the hydraulic motor displacement, followed by orifice area of check valve, inner diameter of pipelines, and charging pressure of accumulator, while the effects of charging volume of accumulator were quite limited.

  3. Hydraulic design development of Xiluodu Francis turbine

    International Nuclear Information System (INIS)

    Wang, Y L; Li, G Y; Shi, Q H; Wang, Z N

    2012-01-01

    Hydraulic optimization design with CFD (Computational Fluid Dynamics) method, hydraulic optimization measures and model test results in the hydraulic development of Xiluodu hydropower station by DFEM (Dongfang Electric Machinery) of DEC (Dongfang Electric Corporation) of China were analyzed in this paper. The hydraulic development conditions of turbine, selection of design parameter, comparison of geometric parameters and optimization measure of turbine flow components were expatiated. And the measures of improving turbine hydraulic performance and the results of model turbine acceptance experiment were discussed in details.

  4. Primary system thermal hydraulics of future Indian fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Velusamy, K., E-mail: kvelu@igcar.gov.in [Thermal Hydraulics Section, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Natesan, K.; Maity, Ram Kumar; Asokkumar, M.; Baskar, R. Arul; Rajendrakumar, M.; Sarathy, U. Partha; Selvaraj, P.; Chellapandi, P. [Thermal Hydraulics Section, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Kumar, G. Senthil; Jebaraj, C. [AU-FRG Centre for CAD/CAM, Anna University, Chennai 600 025 (India)

    2015-12-01

    Highlights: • We present innovative design options proposed for future Indian fast reactor. • These options have been validated by extensive CFD simulations. • Hotspot factors in fuel subassembly are predicted by parallel CFD simulations. • Significant safety improvement in the thermal hydraulic design is quantified. - Abstract: As a follow-up to PFBR (Indian prototype fast breeder reactor), many FBRs of 500 MWe capacity are planned. The focus of these future FBRs is improved economy and enhanced safety. They are envisaged to have a twin-unit concept. Design and construction experiences gained from PFBR project have provided motivation to achieve an optimized design for future FBRs with significant design changes for many critical components. Some of the design changes include, (i) provision of four primary pipes per primary sodium pump, (ii) inner vessel with single torus lower part, (iii) dome shape roof slab supported on reactor vault, (iv) machined thick plate rotating plugs, (v) reduced main vessel diameter with narrow-gap cooling baffles and (vi) safety vessel integrated with reactor vault. This paper covers thermal hydraulic design validation of the chosen options with respect to hot and cold pool thermal hydraulics, flow requirement for main vessel cooling, inner vessel temperature distribution, safety analysis of primary pipe rupture event, adequacy of decay heat removal capacity by natural convection cooling, cold pool transient thermal loads and thermal management of top shield and reactor vault.

  5. Design and analysis of hydraulic ram water pumping system

    Science.gov (United States)

    Hussin, N. S. M.; Gamil, S. A.; Amin, N. A. M.; Safar, M. J. A.; Majid, M. S. A.; Kazim, M. N. F. M.; Nasir, N. F. M.

    2017-10-01

    The current pumping system (DC water pump) for agriculture is powered by household electricity, therefore, the cost of electricity will be increased due to the higher electricity consumption. In addition, the water needs to be supplied at different height of trees and different places that are far from the water source. The existing DC water pump can pump the water to 1.5 m height but it cost money for electrical source. The hydraulic ram is a mechanical water pump that suitable used for agriculture purpose. It can be a good substitute for DC water pump in agriculture use. The hydraulic ram water pumping system has ability to pump water using gravitational energy or the kinetic energy through flowing source of water. This project aims to analyze and develop the water ram pump in order to meet the desired delivery head up to 3 meter height with less operation cost. The hydraulic ram is designed using CATIA software. Simulation work has been done using ANSYS CFX software to validate the working concept. There are three design were tested in the experiment study. The best design reached target head of 3 m with 15% efficiency and flow rate of 11.82l/min. The results from this study show that the less diameter of pressure chamber and higher supply head will create higher pressure.

  6. Diameter-dependent hydrophobicity in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kyakuno, Haruka, E-mail: h-kyakuno@kanagawa-u.ac.jp [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Institute of Physics, Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Fukasawa, Mamoru; Ichimura, Ryota; Nakai, Yusuke; Maniwa, Yutaka, E-mail: maniwa@phys.se.tmu.ac.jp [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Matsuda, Kazuyuki [Institute of Physics, Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Miyata, Yasumitsu [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); PRESTO, JST, Kawaguchi 332-0012 (Japan); Saito, Takeshi [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565 (Japan)

    2016-08-14

    Single-wall carbon nanotubes (SWCNTs) are a good model system that provides atomically smooth nanocavities. It has been reported that water-SWCNTs exhibit hydrophobicity depending on the temperature T and the SWCNT diameter D. SWCNTs adsorb water molecules spontaneously in their cylindrical pores around room temperature, whereas they exhibit a hydrophilic-hydrophobic transition or wet-dry transition (WDT) at a critical temperature T{sub wd} ≈ 220-230 K and above a critical diameter D{sub c} ≈ 1.4-1.6 nm. However, details of the WDT phenomenon and its mechanism remain unknown. Here, we report a systematic experimental study involving X-ray diffraction, optical microscopy, and differential scanning calorimetry. It is found that water molecules inside thick SWCNTs (D > D{sub c}) evaporate and condense into ice Ih outside the SWCNTs at T{sub wd} upon cooling, and the ice Ih evaporates and condenses inside the SWCNTs upon heating. On the other hand, residual water trapped inside the SWCNTs below T{sub wd} freezes. Molecular dynamics simulations indicate that upon lowering T, the hydrophobicity of thick SWCNTs increases without any structural transition, while the water inside thin SWCNTs (D < D{sub c}) exhibits a structural transition, forming an ordered ice. This ice has a well-developed hydrogen bonding network adapting to the cylindrical pores of the SWCNTs. Thus, the unusual diameter dependence of the WDT is attributed to the adaptability of the structure of water to the pore dimension and shape.

  7. Retrobulbar diameter of optic nerve in glaucoma

    Directory of Open Access Journals (Sweden)

    Stefanović Ivan

    2009-01-01

    Full Text Available Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05. Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values, even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.

  8. 29 mm Diameter Target Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Naranjo, Angela Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Romero, Frank Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-10-23

    After numerous delays, the test of the 29 mm diameter target was conducted on 8/18/2017. The complete target design report, dated 8/15/2016, is reproduced below for completeness. This describes in detail the 10 disk target with varying thickness disks. The report presents and discusses the test results. In brief summary, there appears to have been multiple instrumentation errors. Measured temperatures, pressures and IR camera window temperature measurement are all suspect. All tests were done at 35 MeV, with 171 μA current, or 6 kW of beam power.

  9. Advanced energy saving hydraulic elevator

    Energy Technology Data Exchange (ETDEWEB)

    Garrido, A.; Sevilleja, J.; Servia, A.

    1993-08-24

    An hydraulic elevator is described comprising: a counterweighted elevator comprising a car, a counterweight, and a rope connecting the car and the counterweight; a ram having a first reaction surface for driving one of the car or the counterweight upwardly and a second reaction surface for driving one of the car or the counterweight downwardly; multiplier means for moving the car a distance greater than a stroke of the ram, the multiplier means connecting the ram to the counterweighted elevator, the multiplier means comprising: a first pulley; a second pulley; means for rigidly connecting the first and second pulley, the means having a length corresponding to a rise of the hydraulic elevator, the means attaching to the ram; and a pulley rope which: has a first end attaching to a first fixed point, extends about the first pulley, extends about the second pulley, and has a second end attaching to a second fixed point.

  10. Model for polygonal hydraulic jumps

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Watanabe, Shinya; Bohr, Tomas

    2012-01-01

    We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers [Nature (London) 392, 767 (1998); Nonlinearity 12, 1 (1999); Physica B 228, 1 (1996)], based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy...... nonhydrostatic pressure contributions from surface tension in light of recent observations by Bush and co-workers [J. Fluid Mech. 558, 33 (2006); Phys. Fluids 16, S4 (2004)]. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal...... states. A truncated but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a polygon with N corners...

  11. Thermal-hydraulic performance of a multiple jet cooling module with a concave dimple array in a helium-cooled divertor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyo-Yeon; Kim, Kwang-Yong, E-mail: kykim@inha.ac.kr

    2017-01-15

    A numerical study was performed to evaluate the thermal-hydraulic performance of a finger type cooling module, where multiple jets impinge on the surface with concave dimples, in the divertor of a nuclear fusion reactor. Conjugate heat transfer was analyzed in both the solid and fluid domains using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The computational domain consisted of a single fluid domain and three solid domains: tile, thimble, and cartridge. The numerical results for the temperature variation on the tile were validated in comparison with the experimental data. A parametric study was performed with two design variables, the ratios of dimple diameter and dimple height to the nozzle diameter, and two dimple arrays (inline and staggered arrays). The parametric study showed that the heat transfer rate was increased by up to 2.62% by introducing concave dimples, and that the heat transfer and pressure drop performances increased with increasing diameter and height of the dimples for a specified dimple array.

  12. Free surface and hydraulic phenomena in a windowless symmetrical target

    Energy Technology Data Exchange (ETDEWEB)

    Cascone, R.; Salve, M. de; Malandrone, M.; Panella, B. [Politecnico di Torino, Dipt. di Energetica, Torino (Italy)

    2001-07-01

    In the windowless concept for the Accelerator Driven Systems target the liquid flow in the spallation region must be able to remove the volumetric thermal power due to the proton interactions with nuclei. In this paper the hydraulic phenomena of a basic symmetrical windowless target configuration with two concentric cylinders have been studied. The tests were aimed to measure the profile of the free surface of the flow and the liquid velocity field, by using water as hydraulic equivalent to lead-bismuth eutectic fluid. The test section consists of two concentric plexiglass pipes (inner cylinder diameter 200 mm, outer cylinder diameter 290 mm) where the water flows up in the annular region and flows down in the central region. The most important experimental parameters are the fluid level measured from the top edge of the inner cylinder and the imposed flow rate. The experiments have been carried out at room temperature in the following range: flow rate from 2.5 to 20 kg/s; fluid level at zero flow rate from -50 to 186 mm. (authors)

  13. GCFR thermal-hydraulic experiments

    International Nuclear Information System (INIS)

    Schlueter, G.; Baxi, C.B.; Dalle Donne, M.; Gat, U.; Fenech, H.; Hanson, D.; Hudina, M.

    1980-01-01

    The thermal-hydraulic experimental studies performed and planned for the Gas-Cooled Fast Reactor (GCFR) core assemblies are described. The experiments consist of basic studies performed to obtain correlations, and bundle experiments which provide input for code validation and design verification. These studies have been performed and are planned at European laboratories, US national laboratories, Universities in the US, and at General Atomic Company

  14. Hysteresis phenomena in hydraulic measurement

    International Nuclear Information System (INIS)

    Ran, H J; Farhat, M; Luo, X W; Chen, Y L; Xu, H Y

    2012-01-01

    Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

  15. Helmholtz resonance in a piezoelectric–hydraulic pump-based hybrid actuator

    International Nuclear Information System (INIS)

    Kim, Gi-Woo; Wang, K W

    2011-01-01

    This paper demonstrates that a hydraulically acting Helmholtz resonator can exist in a piezoelectric–hydraulic pump (PHP) based hybrid actuator, which in turn affects the volumetric efficiency of the PHP. The simulation and experimental results illustrate the effect of Helmholtz resonance on the flow rate performance of the PHP. The study also shows how to shift the Helmholtz resonant frequency to a higher value through changing parameters such as the cylinder diameter and the effective bulk modulus of the working fluid, which will improve the volumetric efficiency and broaden the operating frequency range of the PHP actuator

  16. Characterisation of karst hydrogeology in Western Ireland using geophysical and hydraulic modelling techniques

    Directory of Open Access Journals (Sweden)

    T. McCormack

    2017-04-01

    New hydrological insights for the region: Results suggest two primary pathways of northwards groundwater flow in the catchment, a fault which discharges offshore, and a ∼2 m diameter karst conduit running underneath the catchment lowlands against the prevailing geological dip. This conduit, whose existence was suspected but never confirmed, links a large ephemeral lake to the coast where it discharges intertidally. Hydraulic modelling indicates that the conduit network is a complex mixture of constrictions with multiple inlets and outlets. Two ephemeral lakes are shown to be hydraulically discontinuous, either drained separately or linked by a low pressure channel.

  17. Compatibility between Hydraulic and Mechanical Properties of Ceramic Water Filters

    Directory of Open Access Journals (Sweden)

    Riyadh Z. Al Zubaidy

    2017-05-01

    Full Text Available In this paper, ceramic water filters were produced by using ten mixtures of different ratios of red clay and sawdust under different production conditions. The physical properties of these filters were tested. The production conditions include five press pressures ranged from 10 to 50MPa and a firing schedule having three different final temperatures of 1000, 1070, and 1100˚C. The tests results of the physical properties were used to obtain best compatibility between the hydraulic and the mechanical properties of these filters. Results showed that as the press pressure and the firing temperature are increased, the bulk density and the compressive and bending strengths of the produced filters are increased, while, the porosity and absorption are decreased. As the sawdust content is increased the bulk density and the compressive and bending strengths are decreased, while, the porosity and absorption are increased. High hydraulic conductivity is obtained at a firing temperature of 1070˚C when the sawdust content is less than 10%. Otherwise, it is increased as sawdust content and the firing temperature are increased. Filters made of mixture 92.5% red clay and 7.5% sawdust formed . under a press pressure of 20MPa and a firing temperature of 1070˚C gave the best compatibility between hydraulic and mechanical properties. In this case, the hydraulic conductivity was 50mm/day, the compressive strength was 14MPa, and the bending strength was 10.8MPa.

  18. Computing in Hydraulic Engineering Education

    Science.gov (United States)

    Duan, J. G.

    2011-12-01

    Civil engineers, pioneers of our civilization, are rarely perceived as leaders and innovators in modern society because of retardations in technology innovation. This crisis has resulted in the decline of the prestige of civil engineering profession, reduction of federal funding on deteriorating infrastructures, and problems with attracting the most talented high-school students. Infusion of cutting-edge computer technology and stimulating creativity and innovation therefore are the critical challenge to civil engineering education. To better prepare our graduates to innovate, this paper discussed the adaption of problem-based collaborative learning technique and integration of civil engineering computing into a traditional civil engineering curriculum. Three interconnected courses: Open Channel Flow, Computational Hydraulics, and Sedimentation Engineering, were developed with emphasis on computational simulations. In Open Channel flow, the focuses are principles of free surface flow and the application of computational models. This prepares students to the 2nd course, Computational Hydraulics, that introduce the fundamental principles of computational hydraulics, including finite difference and finite element methods. This course complements the Open Channel Flow class to provide students with in-depth understandings of computational methods. The 3rd course, Sedimentation Engineering, covers the fundamentals of sediment transport and river engineering, so students can apply the knowledge and programming skills gained from previous courses to develop computational models for simulating sediment transport. These courses effectively equipped students with important skills and knowledge to complete thesis and dissertation research.

  19. Control rod driving hydraulic device

    International Nuclear Information System (INIS)

    Sugano, Hiroshi.

    1993-01-01

    In a control rod driving hydraulic device for an improved BWR type reactor, a bypass pipeline is disposed being branched from a scram pipeline, and a control orifice and a throttle valve are interposed to the bypass pipeline for restricting pressure. Upon occurrence of scram, about 1/2 of water quantity flowing from an accumulator of a hydraulic control unit to the lower surface of a piston of control rod drives by way of a scram pipeline is controlled by the restricting orifice and the throttle valve, by which the water is discharged to a pump suction pipeline or other pipelines by way of the bypass pipeline. With such procedures, a function capable of simultaneously conducting scram for two control rod drives can be attained by one hydraulic control unit. Further, an excessive peak pressure generated by a water hammer phenomenon in the scram pipeline or the control rod drives upon occurrence of scram can be reduced. Deformation and failure due to the excessive peak pressure can be prevented, as well as vibrations and degradation of performance of relevant portions can be prevented. (N.H.)

  20. Hydraulic Shearing and Hydraulic Jacking Observed during Hydraulic Stimulations in Fractured Geothermal Reservoir in Pohang, Korea

    Science.gov (United States)

    Min, K. B.; Park, S.; Xie, L.; Kim, K. I.; Yoo, H.; Kim, K. Y.; Choi, J.; Yoon, K. S.; Yoon, W. S.; Lee, T. J.; Song, Y.

    2017-12-01

    Enhanced Geothermal System (EGS) relies on sufficient and irreversible enhancement of reservoir permeability through hydraulic stimulation and possibility of such desirable change of permeability is an open question that can undermine the universality of EGS concept. We report results of first hydraulic stimulation campaign conducted in two deep boreholes in fractured granodiorite geothermal reservoir in Pohang, Korea. Borehole PX-1, located at 4.22 km, was subjected to the injection of 3,907 m3 with flow rate of up to 18 kg/s followed by bleeding off of 1,207 m3. The borehole PX-2, located at 4.35 km, was subjected to the injection of 1,970 m3 with flow rate of up to 46 kg/sIn PX-1, a sharp distinct decline of wellhead pressure was observed at around 16 MPa of wellhead pressure which was similar to the predicted injection pressure to induce hydraulic shearing. Injectivity interpretation before and after the hydraulic shearing indicates that permanent increase of permeability was achieved by a factor of a few. In PX-2, however, injectivity was very small and hydraulic shearing was not observed due possibly to the near wellbore damage made by the remedying process of lost circulation such as using lost circulation material during drilling. Flow rate of larger than 40 kg/s was achieved at very high well head pressure of nearly 90 MPa. Hydraulic jacking, that is reversible opening and closure of fracture with change of injection pressure, was clearly observed. Although sharp increase of permeability due to fracture opening was achieved with elevated injection pressure, the increased permeability was reversed with decreased injection pressure.Two contrasting response observed in the same reservoir at two different boreholes which is apart only 600 m apart provide important implication that can be used for the stimulation strategy for EGS.This work was supported by the New and Renewable Energy Technology Development Program of the Korea Institute of Energy Technology

  1. Leaf area compounds height-related hydraulic costs of water transport in Oregon White Oak trees.

    Science.gov (United States)

    N. Phillips; B. J. Bond; N. G. McDowell; Michael G. Ryan; A. Schauer

    2003-01-01

    The ratio of leaf to sapwood area generally decreases with tree size, presumably to moderate hydraulic costs of tree height. This study assessed consequences of tree size and leaf area on water flux in Quercus garryana Dougl. ex. Hook (Oregon White Oak), a species in which leaf to sapwood area ratio increases with tree size. We tested hypotheses that...

  2. Design, test and model of a hybrid magnetostrictive hydraulic actuator

    International Nuclear Information System (INIS)

    Chaudhuri, Anirban; Yoo, Jin-Hyeong; Wereley, Norman M

    2009-01-01

    The basic operation of hybrid hydraulic actuators involves high frequency bi-directional operation of an active material that is converted to uni-directional motion of hydraulic fluid using valves. A hybrid actuator was developed using magnetostrictive material Terfenol-D as the driving element and hydraulic oil as the working fluid. Two different lengths of Terfenol-D rod, 51 and 102 mm, with the same diameter, 12.7 mm, were used. Tests with no load and with load were carried out to measure the performance for uni-directional motion of the output piston at different pumping frequencies. The maximum no-load flow rates were 24.8 cm 3 s −1 and 22.7 cm 3 s −1 with the 51 mm and 102 mm long rods respectively, and the peaks were noted around 325 Hz pumping frequency. The blocked force of the actuator was close to 89 N in both cases. A key observation was that, at these high pumping frequencies, the inertial effects of the fluid mass dominate over the viscous effects and the problem becomes unsteady in nature. In this study, we also develop a mathematical model of the hydraulic hybrid actuator in the time domain to show the basic operational principle under varying conditions and to capture phenomena affecting system performance. Governing equations for the pumping piston and output shaft were obtained from force equilibrium considerations, while compressibility of the working fluid was taken into account by incorporating the bulk modulus. Fluid inertia was represented by a lumped parameter approach to the transmission line model, giving rise to strongly coupled ordinary differential equations. The model was then used to calculate the no-load velocities of the actuator at different pumping frequencies and simulation results were compared with experimental data for model validation

  3. Variation of Desert Soil Hydraulic Properties with Pedogenic Maturity

    Science.gov (United States)

    Nimmo, J. R.; Perkins, K. S.; Mirus, B. B.; Schmidt, K. M.; Miller, D. M.; Stock, J. D.; Singha, K.

    2006-12-01

    Older alluvial desert soils exhibit greater pedogenic maturity, having more distinct desert pavements, vesicular (Av) horizons, and more pronounced stratification from processes such as illuviation and salt accumulation. These and related effects strongly influence the soil hydraulic properties. Older soils have been observed to have lower saturated hydraulic conductivity, and possibly greater capacity to retain water, but the quantitative effect of specific pedogenic features on the soil water retention or unsaturated hydraulic conductivity (K) curves is poorly known. With field infiltration/redistribution experiments on three different-aged soils developed within alluvial wash deposits in the Mojave National Preserve, we evaluated effective hydraulic properties over a scale of several m horizontally and to 1.5 m depth. We then correlated these properties with pedogenic features. The selected soils are (1) recently deposited sediments, (2) a soil of early Holocene age, and (3) a highly developed soil of late Pleistocene age. In each experiment we ponded water in a 1-m-diameter infiltration ring for 2.3 hr. For several weeks we monitored subsurface water content and matric pressure using surface electrical resistance imaging, dielectric-constant probes, heat-dissipation probes, and tensiometers. Analysis of these data using an inverse modeling technique gives the water retention and K properties needed for predictive modeling. Some properties show a consistent trend with soil age. Progressively more developed surface and near-surface features such as desert pavement and Av horizons are the likely cause of an observed consistent decline of infiltration capacity with soil age. Other properties, such as vertical flow retardation by layer contrasts, appear to have a more complicated soil-age dependence. The wash deposits display distinct depositional layering that has a retarding effect on vertical flow, an effect that may be less pronounced in the older Holocene soil

  4. Elevational trends in hydraulic efficiency and safety of Pinus cembra roots.

    Science.gov (United States)

    Losso, Adriano; Nardini, Andrea; Nolf, Markus; Mayr, Stefan

    2016-04-01

    In alpine regions, elevational gradients in environmental parameters are reflected by structural and functional changes in plant traits. Elevational changes in plant water relations have also been demonstrated, but comparable information on root hydraulics is generally lacking. We analyzed the hydraulic efficiency (specific hydraulic conductivity k s, entire root system conductance K R) and vulnerability to drought-induced embolism (water potential at 50 % loss of conductivity Ψ 50) of the roots of Pinus cembra trees growing along an elevational transect of 600 m. Hydraulic parameters of the roots were compared with those of the stem and related to anatomical traits {mean conduit diameter (d), wall reinforcement [(t/b)(2)]}. We hypothesized that temperature-related restrictions in root function would cause a progressive limitation of hydraulic efficiency and safety with increasing elevation. We found that both root k s and K R decreased from low (1600 m a.s.l.: k s 5.6 ± 0.7 kg m(-1) s(-1) MPa(-1), K R 0.049 ± 0.005 kg m(-2) s (-1) MPa(-1)) to high elevation (2100 m a.s.l.: k s 4.2 ± 0.6 kg m(-1) s(-1) MPa(-1), K R 0.035 ± 0.006 kg m(-2) s(-1) MPa(-1)), with small trees showing higher K R than large trees. k s was higher in roots than in stems (0.5 ± 0.05 kg m(-1)s(-1)MPa(-1)). Ψ 50 values were similar across elevations and overall less negative in roots (Ψ 50 -3.6 ± 0.1 MPa) than in stems (Ψ 50 -3.9 ± 0.1 MPa). In roots, large-diameter tracheids were lacking at high elevation and (t/b)(2) increased, while d did not change. The elevational decrease in root hydraulic efficiency reflects a limitation in timberline tree hydraulics. In contrast, hydraulic safety was similar across elevations, indicating that avoidance of hydraulic failure is important for timberline trees. As hydraulic patterns can only partly be explained by the anatomical parameters studied, limitations and/or adaptations at the pit level are likely.

  5. Thirty-centimeter-diameter ion milling source

    International Nuclear Information System (INIS)

    Robinson, R.S.

    1978-01-01

    A 30 cm beam diameter ion source has been designed and fabricated for micromachining and sputtering applications. An argon ion current density of 1 mA/cm 2 at 500 eV ion energy was selected as a design operating condition. The completed ion source met the design criteria at this operating condition with a uniform and well-collimated beam having an average variation in current density of +- 5% over the center of 20 cm of the beam. This ion source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. Langmuir probe surveys of the source plasma support the design concepts of a multipole field and a circumferential cathode to enhance plasma uniformity

  6. Slug Flow Analysis in Vertical Large Diameter Pipes

    Science.gov (United States)

    Roullier, David

    The existence of slug flow in vertical co-current two-phase flow is studied experimentally and theoretically. The existence of slug flow in vertical direction implies the presence of Taylor bubbles separated by hydraulically sealed liquid slugs. Previous experimental studies such as Ombere-Ayari and Azzopardi (2007) showed the evidence of the non-existence of Taylor bubbles for extensive experimental conditions. Models developed to predict experimental behavior [Kocamustafaogullari et al. (1984), Jayanti and Hewitt. (1990) and Kjoolas et al. (2017)] suggest that Taylor bubbles may disappear at large diameters and high velocities. A 73-ft tall and 101.6-mm internal diameter test facility was used to conduct the experiments allowing holdup and pressure drop measurements at large L/D. Superficial liquid and gas velocities varied from 0.05-m/s to 0.2 m/s and 0.07 m/s to 7.5 m/s, respectively. Test section pressure varied from 38 psia to 84 psia. Gas compressibility effect was greatly reduced at 84 psia. The experimental program allowed to observe the flow patterns for flowing conditions near critical conditions predicted by previous models (air-water, 1016 mm ID, low mixture velocities). Flow patterns were observed in detail using wire-mesh sensor measurements. Slug-flow was observed for a narrow range of experimental conditions at low velocities. Churn-slug and churn-annular flows were observed for most of the experimental data-points. Cap-bubble flow was observed instead of bubbly flow at low vSg. Wire-mesh measurements showed that the liquid has a tendency to remain near to the walls. The standard deviation of radial holdup profile correlates to the flow pattern observed. For churn-slug flow, the profile is convex with a single maximum near the pipe center while it exhibits a concave shape with two symmetric maxima close to the wall for churn-annular flow. The translational velocity was measured by two consecutive wire-mesh sensor crosscorrelation. The results show

  7. The relationship between reference canopy conductance and simplified hydraulic architecture

    Science.gov (United States)

    Novick, Kimberly; Oren, Ram; Stoy, Paul; Juang, Jehn-Yih; Siqueira, Mario; Katul, Gabriel

    2009-06-01

    Terrestrial ecosystems are dominated by vascular plants that form a mosaic of hydraulic conduits to water movement from the soil to the atmosphere. Together with canopy leaf area, canopy stomatal conductance regulates plant water use and thereby photosynthesis and growth. Although stomatal conductance is coordinated with plant hydraulic conductance, governing relationships across species has not yet been formulated at a practical level that can be employed in large-scale models. Here, combinations of published conductance measurements obtained with several methodologies across boreal to tropical climates were used to explore relationships between canopy conductance rates and hydraulic constraints. A parsimonious hydraulic model requiring sapwood-to-leaf area ratio and canopy height generated acceptable agreement with measurements across a range of biomes (r2=0.75). The results suggest that, at long time scales, the functional convergence among ecosystems in the relationship between water-use and hydraulic architecture eclipses inter-specific variation in physiology and anatomy of the transport system. Prognostic applicability of this model requires independent knowledge of sapwood-to-leaf area. In this study, we did not find a strong relationship between sapwood-to-leaf area and physical or climatic variables that are readily determinable at coarse scales, though the results suggest that climate may have a mediating influence on the relationship between sapwood-to-leaf area and height. Within temperate forests, canopy height alone explained a large amount of the variance in reference canopy conductance (r2=0.68) and this relationship may be more immediately applicable in the terrestrial ecosystem models.

  8. Internal coordination between hydraulics and stomatal control in leaves.

    Science.gov (United States)

    Brodribb, Tim J; Jordan, Gregory J

    2008-11-01

    The stomatal response to changing leaf-atmospheric vapour pressure gradient (D(l)) is a crucial yet enigmatic process that defines the daily course of leaf gas exchange. Changes in the hydration of epidermal cells are thought to drive this response, mediated by the transpiration rate and hydraulic conductance of the leaf. Here, we examine whether species-specific variation in the sensitivity of leaves to perturbation of D(l) is related to the efficiency of water transport in the leaf (leaf hydraulic conductivity, K(leaf)). We found good correlation between maximum liquid (K(leaf)) and gas phase conductances (g(max)) in leaves, but there was no direct correlation between normalized D(l) sensitivity and K(leaf). The impact of K(leaf) on D(l) sensitivity in our diverse sample of eight species was important only after accounting for the strong relationship between K(leaf) and g(max). Thus, the ratio of g(max)/K(leaf) was strongly correlated with stomatal sensitivity to D(l). This ratio is an index of the degree of hydraulic buffering of the stomata against changes in D(l), and species with high g(max) relative to K(leaf) were the most sensitive to D(l) perturbation. Despite the potentially high adaptive significance of this phenomenon, we found no significant phylogenetic or ecological trend in our species.

  9. Sugar maple height-diameter and age-diameter relationships in an uneven-aged northern hardwood stand

    Science.gov (United States)

    Laura S. Kenefic; R.D. Nyland

    1999-01-01

    Sugar maple (Acer saccharum Marsh.) height-diameter and age-diameter relationships are explored in a balanced uneven-aged northern hardwood stand in central New York. Results show that although both height and age vary considerably with diameter, these relationships can be described by statistically valid equations. The age-diameter relationship...

  10. A new method for measuring coronary artery diameters with CT spatial profile curves

    International Nuclear Information System (INIS)

    Shimamoto, Ryoichi; Suzuki, Jun-ichi; Yamazaki, Tadashi; Tsuji, Taeko; Ohmoto, Yuki; Morita, Toshihiro; Yamashita, Hiroshi; Honye, Junko; Nagai, Ryozo; Akahane, Masaaki; Ohtomo, Kuni

    2007-01-01

    Purpose: Coronary artery vascular edge recognition on computed tomography (CT) angiograms is influenced by window parameters. A noninvasive method for vascular edge recognition independent of window setting with use of multi-detector row CT was contrived and its feasibility and accuracy were estimated by intravascular ultrasound (IVUS). Methods: Multi-detector row CT was performed to obtain 29 CT spatial profile curves by setting a line cursor across short-axis coronary angiograms processed by multi-planar reconstruction. IVUS was also performed to determine the reference coronary diameter. IVUS diameter was fitted horizontally between two points on the upward and downward slopes of the profile curves and Hounsfield number was measured at the fitted level to test seven candidate indexes for definition of intravascular coronary diameter. The best index from the curves should show the best agreement with IVUS diameter. Results: Of the seven candidates the agreement was the best (agreement: 16 ± 11%) when the two ratios of Hounsfield number at the level of IVUS diameter over that at the peak on the profile curves were used with water and with fat as the background tissue. These edge definitions were achieved by cutting the horizontal distance by the curves at the level defined by the ratio of 0.41 for water background and 0.57 for fat background. Conclusions: Vascular edge recognition of the coronary artery with CT spatial profile curves was feasible and the contrived method could define the coronary diameter with reasonable agreement

  11. Combined hydraulic and regenerative braking system

    Science.gov (United States)

    Venkataperumal, R.R.; Mericle, G.E.

    1979-08-09

    A combined hydraulic and regenerative braking system and method for an electric vehicle is disclosed. The braking system is responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

  12. Optimization of hydraulic turbine diffuser

    Directory of Open Access Journals (Sweden)

    Moravec Prokop

    2016-01-01

    Full Text Available Hydraulic turbine diffuser recovers pressure energy from residual kinetic energy on turbine runner outlet. Efficiency of this process is especially important for high specific speed turbines, where almost 50% of available head is utilized within diffuser. Magnitude of the coefficient of pressure recovery can be significantly influenced by designing its proper shape. Present paper focuses on mathematical shape optimization method coupled with CFD. First method is based on direct search Nelder-Mead algorithm, while the second method employs adjoint solver and morphing. Results obtained with both methods are discussed and their advantages/disadvantages summarized.

  13. The Influence of Waist Thickness of Dolosse on the Hydraulic Stability of Dolosse Armour

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Brejnegaard-Nielsen, Torben

    1987-01-01

    stability was studied. A low packing density of approximately 0.65 was used corresponding to a two-layer armour with high porosity. From the results it is concluded that the hydraulic stability of Dolos armour is not very sensitive to variations in the waist to height ratio. Only for damage levels exceeding...... displacement of approximately 5% of the armour blocks in the most exposed area there seems to be a significant decrease in hydraulic stability with increasing waist to height ratio. Thus the waist ratio only influences the residual hydraulic stability. Based on a short discussion of stressed in armour units...... underlines the need for adoption of more restrictive safety factors than generally used in rubble mound breakwater design. It also supports the idea of a probabilistic approach in the design process....

  14. A HISTORICAL PERSPECTIVE OF NUCLEAR THERMAL HYDRAULICS

    Energy Technology Data Exchange (ETDEWEB)

    D’Auria, F; Rohatgi, Upendra S.

    2017-01-12

    The nuclear thermal-hydraulics discipline was developed following the needs for nuclear power plants (NPPs) and, to a more limited extent, research reactors (RR) design and safety. As in all other fields where analytical methods are involved, nuclear thermal-hydraulics took benefit of the development of computers. Thermodynamics, rather than fluid dynamics, is at the basis of the development of nuclear thermal-hydraulics together with the experiments in complex two-phase situations, namely, geometry, high thermal density, and pressure.

  15. Reactor Thermal Hydraulic Numerical Calculation And Modeling

    International Nuclear Information System (INIS)

    Duong Ngoc Hai; Dang The Ba

    2008-01-01

    In the paper the results of analysis of thermal hydraulic state models using the numerical codes such as COOLOD, EUREKA and RELAP5 for simulation of the reactor thermal hydraulic states are presented. The calculations, analyses of reactor thermal hydraulic state and safety were implemented using different codes. The received numerical results, which were compared each to other, to experiment measurement of Dalat (Vietnam) research reactor and published results, show their appropriateness and capacity for analyses of different appropriate cases. (author)

  16. Tracking control of the hydraulically actuated flexible manipulator

    International Nuclear Information System (INIS)

    Kwon, D.S.; Babcock, S.M.; Burks, B.L.; Kress, R.L.

    1995-01-01

    The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Department of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task. Because high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems are expected to use hydraulic actuators and to exhibit significant structural flexibility. The controller has been designed to compensate for the hydraulic actuator dynamics by using a load-compensated velocity feedforward loop and to increase the bandwidth by using a pressure feed backloop. Shaping filter techniques have been applied as a feedforward controller to avoid structural vibrations during operation. Among various types of shaping filter methods investigated an approach, referred to as a ''feedforward simulation filter'' that uses embedded simulation, has been presented

  17. Parametric study on thermal-hydraulic characteristics of high conversion light water reactor

    International Nuclear Information System (INIS)

    Mori, Takamasa; Nakagawa, Masayuki; Fujii, Sadao.

    1988-11-01

    To assess the feasibility of high conversion light water reactors (HCLWRs) from the thermal-hydraulic viewpoint, parametric study on thermal-hydraulic characteristics of HCLWR has been carried out by using a unit cell model. It is assumed that a HCLWR core is contained in a current 1000 MWe PWR plant. At the present study, reactor core parameters such as fuel pin diameter, pitch, core height and linear heat rate are widely and parametrically changed to survey the relation between these parameters and the basic thermal-hydraulic characteristics, i.e. maximum fuel temperature, minimum DNBR, reduction of reactor thermal output and so on. The validity of the unit cell model used has been ensured by comparison with the result of a subchannel analysis carried out for a whole core. (author)

  18. Contrasting xylem vessel constraints on hydraulic conductivity between native and non-native woody understory species

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    2013-11-01

    Full Text Available We examined the hydraulic properties of 82 native and non-native woody species common to forests of Eastern North America, including several congeneric groups, representing a range of anatomical wood types. We observed smaller conduit diameters with greater frequency in non-native species, corresponding to lower calculated potential vulnerability to cavitation index. Non-native species exhibited higher vessel-grouping in metaxylem compared with native species, however, solitary vessels were more prevalent in secondary xylem. Higher frequency of solitary vessels in secondary xylem was related to a lower potential vulnerability index. We found no relationship between anatomical characteristics of xylem, origin of species and hydraulic conductivity, indicating that non-native species did not exhibit advantageous hydraulic efficiency over native species. Our results confer anatomical advantages for non-native species under the potential for cavitation due to freezing, perhaps permitting extended growing seasons.

  19. Hydraulic nuts (hydranuts) for critical bolted joints

    International Nuclear Information System (INIS)

    Greenwell, S.

    2008-01-01

    HydraNuts replace the original nut and torquing equipment, combining the two functions into one system. Designed for simple installation and operation, HydraNuts are fitted to the stud bolts. Once all HydraNuts are fitted to the application, flexible hydraulic hoses are connected, forming a closed loop hydraulic harness, allowing simultaneous pressurization of all HydraNuts. Hydraulic pressure is obtained by the use of a pumping unit and the resultant load generated is transferred to the studs and flange closure is obtained. Locking rings are rotated into place, supporting the tensioned load mechanically after hydraulic pressure is released. The hose harness is removed. (author)

  20. Dimensionless Energy Conversion Characteristics of an Air-Powered Hydraulic Vehicle

    Directory of Open Access Journals (Sweden)

    Dongkai Shen

    2018-02-01

    Full Text Available Due to the advantages of resource conservation and less exhaust emissions, compressed air-powered vehicle has attracted more and more attention. To improve the power and efficiency of air-powered vehicle, an air-powered hydraulic vehicle was proposed. As the main part of the air-powered hydraulic vehicles, HP transformer (short for Hydropneumatic transformer is used to convert the pneumatic power to higher hydraulic power. In this study, to illustrate the energy conversion characteristics of air-powered hydraulic vehicle, dimensionless mathematical model of the vehicle’s working process was set up. Through experimental study on the vehicle, the dimensionless model was verified. Through simulation study on the vehicle, the following can be obtained: firstly, the increase of the hydraulic chamber orifice and the area ratio of the pistons can lead to a higher output power, while output pressure is just the opposite. Moreover, the increase of the output pressure and the aperture of the hydraulic chamber can lead to a higher efficiency, while area ratio of the pistons played the opposite role. This research can be referred to in the performance and design optimization of the HP transformers.

  1. Estimation of hydraulic jump characteristics of channels with sudden diverging side walls via SVM.

    Science.gov (United States)

    Roushangar, Kiyoumars; Valizadeh, Reyhaneh; Ghasempour, Roghayeh

    2017-10-01

    Sudden diverging channels are one of the energy dissipaters which can dissipate most of the kinetic energy of the flow through a hydraulic jump. An accurate prediction of hydraulic jump characteristics is an important step in designing hydraulic structures. This paper focuses on the capability of the support vector machine (SVM) as a meta-model approach for predicting hydraulic jump characteristics in different sudden diverging stilling basins (i.e. basins with and without appurtenances). In this regard, different models were developed and tested using 1,018 experimental data. The obtained results proved the capability of the SVM technique in predicting hydraulic jump characteristics and it was found that the developed models for a channel with a central block performed more successfully than models for channels without appurtenances or with a negative step. The superior performance for the length of hydraulic jump was obtained for the model with parameters F 1 (Froude number) and (h 2- h 1 )/h 1 (h 1 and h 2 are sequent depth of upstream and downstream respectively). Concerning the relative energy dissipation and sequent depth ratio, the model with parameters F 1 and h 1 /B (B is expansion ratio) led to the best results. According to the outcome of sensitivity analysis, Froude number had the most significant effect on the modeling. Also comparison between SVM and empirical equations indicated the great performance of the SVM.

  2. Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler

    International Nuclear Information System (INIS)

    Kang Huifang; Li Qing; Zhou Gang

    2009-01-01

    It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.

  3. Modeling and stability of electro-hydraulic servo of hydraulic excavator

    Science.gov (United States)

    Jia, Wenhua; Yin, Chenbo; Li, Guo; Sun, Menghui

    2017-11-01

    The condition of the hydraulic excavator is complicated and the working environment is bad. The safety and stability of the control system is influenced by the external factors. This paper selects hydraulic excavator electro-hydraulic servo system as the research object. A mathematical model and simulation model using AMESIM of servo system is established. Then the pressure and flow characteristics are analyzed. The design and optimization of electro-hydraulic servo system and its application in engineering machinery is provided.

  4. Waste system optimization - can diameter selection

    International Nuclear Information System (INIS)

    Ashline, R.C.

    1983-08-01

    The purpose of the waste system optimization study is to define in terms of cost incentives the preferred waste package for HLW which has been converted to glass at a commercial reprocessing plant. The Waste Management Economic Model (WMEM) was employed to analyze the effect of varying important design parameters on the overall net present cost of waste handling. The parameters found to have the greatest effect on the calculated overall net present cost were can diameter, repository type (salt, basalt/bentonite, or welded tuff), allowable areal heat loading, and the repository availability date. The overall net present of a waste handling option is calculated over a 20-year operating period. It includes the total capital and operating costs associated with high-level and intermediate-level liquid waste storage, liquid waste solidification, hulls storage and compaction, and general process trash handling. It also includes the cask leasing and transportation costs associated with each waste type and the waste repository disposal costs. The waste repository disposal costs used in WMEM for this analysis were obtained from Battelle Pacific Northwest Laboratories and thir RECON model. 2 figures, 2 tables

  5. Packing configuration performance for small stem diameters

    International Nuclear Information System (INIS)

    Aikin, J.A.; Spence, C.G.; Cumming, D.

    1997-01-01

    The extensive use of graphite packing and its excellent track record for large isolating valves in CANDU, Primary Heat Transfer (PHT) systems has resulted in an increased application of graphite packing on the conventional side. Many of these applications are in air operated valves (AOVs) where the packing sets are used on small stem diameters (<1 inch) with frequent short-cycling strokes (± 10% of full stroke). The direct application of the proven packing configurations for large isolated valves to control valve application has generated problems such as stiction, packing wear and, in isolated cases, stem stall. To address this issue, a test program was conducted at AECL, CRL by MED branch. The testing showed that by reconfiguring the packing sets and using PTFE wafers reductions in stem friction of 50% at ambient conditions, a 3 fold at hot conditions are achievable. The test program also demonstrated benefits gained in packing wear with different stem roughness finishes and the potential need to exercise small stems valves that see less than full stroke cycling. The paper describes the tests results and provides field support experience. (author)

  6. Verification Test of Hydraulic Performance for Reactor Coolant Pump

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Jun; Kim, Jae Shin; Ryu, In Wan; Ko, Bok Seong; Song, Keun Myung [Samjin Ind. Co., Seoul (Korea, Republic of)

    2010-01-15

    According to this project, basic design for prototype pump and model pump of reactor coolant pump and test facilities has been completed. Basic design for prototype pump to establish structure, dimension and hydraulic performance has been completed and through primary flow analysis by computational fluid dynamics(CFD), flow characteristics and hydraulic performance have been established. This pump was designed with mixed flow pump having the following design requirements; specific velocity(Ns); 1080.9(rpm{center_dot}m{sup 3}/m{center_dot}m), capacity; 3115m{sup 3}/h, total head ; 26.3m, pump speed; 1710rpm, pump efficiency; 77.0%, Impeller out-diameter; 349mm, motor output; 360kw, design pressure; 17MPaG. The features of the pump are leakage free due to no mechanical seal on the pump shaft which insures reactor's safety and law noise level and low vibration due to no cooling fan on the motor which makes eco-friendly product. Model pump size was reduced to 44% of prototype pump for the verification test for hydraulic performance of reactor coolant pump and was designed with mixed flow pump and canned motor having the following design requirements; specific speed(NS); 1060.9(rpm{center_dot}m{sup 3}/m{center_dot}m), capacity; 539.4m{sup 3}/h, total head; 21.0m, pump speed; 3476rpm, pump efficiency; 72.9%, Impeller out-diameter; 154mm, motor output; 55kw, design pressure; 1.0MPaG. The test facilities were designed for verification test of hydraulic performance suitable for pump performance test, homologous test, NPSH test(cavitation), cost down test and pressure pulsation test of inlet and outlet ports. Test tank was designed with testing capacity enabling up to 2000m{sup 3}/h and design pressure 1.0MPaG. Auxiliary pump was designed with centrifugal pump having capacity; 1100m{sup 3}/h, total head; 42.0m, motor output; 190kw

  7. Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography

    International Nuclear Information System (INIS)

    Lucarelli, Claudio Luiz

    1995-01-01

    The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

  8. Xylem hydraulic properties of roots and stems of nine Mediterranean woody species.

    Science.gov (United States)

    Martínez-Vilalta, Jordi; Prat, Ester; Oliveras, Imma; Piñol, Josep

    2002-09-01

    We studied the hydraulic architecture and water relations of nine co-occurring woody species in a Spanish evergreen oak forest over the course of a dry season. Our main objectives were to: (1) test the existence of a trade-off between hydraulic conductivity and security in the xylem, and (2) establish the safety margins at which the species operated in relation to hydraulic failure, and compare these safety margins between species and tissues (roots vs. stems). Our results showed that the relationship between specific hydraulic conductivity (K s) and resistance to cavitation followed a power function with exponent ≈-2, consistent with the existence of a trade-off between conductivity and security in the xylem, and also consistent with a linear relationship between vessel diameter and the size of inter-vessel pores. The diameter of xylem conduits, K s and vulnerability to xylem embolism were always higher in roots than in stems of the same species. Safety margins from hydraulic failure were narrower in roots than in stems. Among species, the water potential (Ψ) at which 50% of conductivity was lost due to embolism ranged between -0.9 and Cistus albidus=Ilex aquifolium>Phillyrea latifolia>Juniperus oxycedrus. Gas exchange and seasonal Ψ minima were in general correlated with resistance to xylem embolism. Hydraulic safety margins differed markedly among species, with some of them (J. oxycedrus, I. aquifolium, P. latifolia) showing a xylem overly resistant to cavitation. We hypothesize that this overly resistant xylem may be related to the shape of the relationship between K s and security we have found.

  9. Numerical simulation of the two-phase flows in a hydraulic coupling by solving VOF model

    International Nuclear Information System (INIS)

    Luo, Y; Zuo, Z G; Liu, S H; Fan, H G; Zhuge, W L

    2013-01-01

    The flow in a partially filled hydraulic coupling is essentially a gas-liquid two-phase flow, in which the distribution of two phases has significant influence on its characteristics. The interfaces between the air and the liquid, and the circulating flows inside the hydraulic coupling can be simulated by solving the VOF two-phase model. In this paper, PISO algorithm and RNG k–ε turbulence model were employed to simulate the phase distribution and the flow field in a hydraulic coupling with 80% liquid fill. The results indicate that the flow forms a circulating movement on the torus section with decreasing speed ratio. In the pump impeller, the air phase mostly accumulates on the suction side of the blades, while liquid on the pressure side; in turbine runner, air locates in the middle of the flow passage. Flow separations appear near the blades and the enclosing boundaries of the hydraulic coupling

  10. Modelling diameter growth, mortality and recruitment of trees in ...

    African Journals Online (AJOL)

    Modelling diameter growth, mortality and recruitment of trees in miombo woodlands of Tanzania. ... Individual tree diameter growth and mortality models, and area-based recruitment models were developed. ... AJOL African Journals Online.

  11. Nineteen-Foot Diameter Explosively Driven Blast Simulator; TOPICAL

    International Nuclear Information System (INIS)

    VIGIL, MANUEL G.

    2001-01-01

    This report describes the 19-foot diameter blast tunnel at Sandia National Laboratories. The blast tunnel configuration consists of a 6 foot diameter by 200 foot long shock tube, a 6 foot diameter to 19 foot diameter conical expansion section that is 40 feet long, and a 19 foot diameter test section that is 65 feet long. Therefore, the total blast tunnel length is 305 feet. The development of this 19-foot diameter blast tunnel is presented. The small scale research test results using 4 inch by 8 inch diameter and 2 foot by 6 foot diameter shock tube facilities are included. Analytically predicted parameters are compared to experimentally measured blast tunnel parameters in this report. The blast tunnel parameters include distance, time, static, overpressure, stagnation pressure, dynamic pressure, reflected pressure, shock Mach number, flow Mach number, shock velocity, flow velocity, impulse, flow duration, etc. Shadowgraphs of the shock wave are included for the three different size blast tunnels

  12. Shiitake mushroom production on small diameter oak logs in Ohio

    Science.gov (United States)

    S.M. Bratkovich

    1991-01-01

    Yields of different strains of shiitake mushrooms (Lentinus edodes) were evaluated when produced on small diameter oak logs in Ohio. Logs averaging between 3-4 inches in diameter were inoculated with four spawn strains in 1985.

  13. Instability of Reference Diameter in the Evaluation of Stenosis After Coronary Angioplasty: Percent Diameter Stenosis Overestimates Dilative Effects Due to Reference Diameter Reduction

    International Nuclear Information System (INIS)

    Hirami, Ryouichi; Iwasaki, Kohichiro; Kusachi, Shozo; Murakami, Takashi; Hina, Kazuyoshi; Matano, Shigeru; Murakami, Masaaki; Kita, Toshimasa; Sakakibara, Noburu; Tsuji, Takao

    2000-01-01

    Purpose: To examine changes in the reference segment luminal diameter after coronary angioplasty.Methods: Sixty-one patients with stable angina pectoris or old myocardial infarction were examined. Coronary angiograms were recorded before coronary angioplasty (pre-angioplasty) and immediately after (post-angioplasty), as well as 3 months after. Artery diameters were measured on cine-film using quantitative coronary angiographic analysis.Results: The diameters of the proximal segment not involved in the balloon inflation and segments in the other artery did not change significantly after angioplasty, but the reference segment diameter significantly decreased (4.7%). More than 10% luminal reduction was observed in seven patients (11%) and more than 5% reduction was observed in 25 patients (41%). More than 5% underestimation of the stenosis was observed in 22 patients (36%) when the post-angioplasty reference diameter was used as the reference diameter, compared with when the pre-angioplasty measurement was used and more than 10% underestimation was observed in five patients (8%).Conclusion: This study indicated that evaluation by percent diameter stenosis, with the reference diameter from immediately after angioplasty, overestimates the dilative effects of coronary angioplasty, and that it is thus better to evaluate the efficacy of angioplasty using the absolute diameter in addition to percent luminal stenosis

  14. Liquid metal thermal-hydraulics

    International Nuclear Information System (INIS)

    Kottowski-Duemenil, H.M.

    1994-01-01

    This textbook is a report of the 26 years activity of the Liquid Metal Boiling Working Group (LMBWG). It summarizes the state of the art of liquid metal thermo-hydraulics achieved through the collaboration of scientists concerned with the development of the Fast Breeder Reactor. The first chapter entitled ''Liquid Metal Boiling Behaviour'', presents the background and boiling mechanisms. This section gives the reader a brief but thorough survey on the superheat phenomena in liquid metals. The second chapter of the text, ''A Review of Single and Two-Phase Flow Pressure Drop Studies and Application to Flow Stability Analysis of Boiling Liquid Metal Systems'' summarizes the difficulty of pressure drop simulation of boiling sodium in core bundles. The third chapter ''Liquid Metal Dry-Out Data for Flow in Tubes and Bundles'' describes the conditions of critical heat flux which limits the coolability of the reactor core. The fourth chapter dealing with the LMFBR specific topic of ''Natural Convection Cooling of Liquid Metal Systems''. This chapter gives a review of both plant experiments and out-of-pile experiments and shows the advances in the development of computing power over the past decade of mathematical modelling ''Subassembly Blockages Suties'' are discussed in chapter five. Chapter six is entitled ''A Review of the Methods and Codes Available for the Calculation on Thermal-Hydraulics in Rod-Cluster and other Geometries, Steady state and Transient Boiling Flow Regimes, and the Validation achieves''. Codes available for the calculation of thermal-hydraulics in rod-clusters and other geometries are reviewed. Chapter seven, ''Comparative Studies of Thermohydraulic Computer Code Simulations of Sodium Boiling under Loss of Flow Conditions'', represents one of the key activities of the LMBWG. Several benchmark exercises were performed with the aim of transient sodium boiling simulation in single channels and bundle blockages under steady state conditions and loss of

  15. Design of Pumps for Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Klit, Peder; Olsen, Stefan; Bech, Thomas Nørgaard

    1999-01-01

    This paper considers the development of two pumps for water hydraulic applications. The pumps are based on two different working principles: The Vane-type pump and the Gear-type pump. Emphasis is put on the considerations that should be made to account for water as the hydraulic fluid.......KEYWORDS: water, pump, design, vane, gear....

  16. Uncertainty in hydraulic tests in fractured rock

    International Nuclear Information System (INIS)

    Ji, Sung-Hoon; Koh, Yong-Kwon

    2014-01-01

    Interpretation of hydraulic tests in fractured rock has uncertainty because of the different hydraulic properties of a fractured rock to a porous medium. In this study, we reviewed several interesting phenomena which show uncertainty in a hydraulic test at a fractured rock and discussed their origins and the how they should be considered during site characterisation. Our results show that the estimated hydraulic parameters of a fractured rock from a hydraulic test are associated with uncertainty due to the changed aperture and non-linear groundwater flow during the test. Although the magnitude of these two uncertainties is site-dependent, the results suggest that it is recommended to conduct a hydraulic test with a little disturbance from the natural groundwater flow to consider their uncertainty. Other effects reported from laboratory and numerical experiments such as the trapping zone effect (Boutt, 2006) and the slip condition effect (Lee, 2014) can also introduce uncertainty to a hydraulic test, which should be evaluated in a field test. It is necessary to consider the way how to evaluate the uncertainty in the hydraulic property during the site characterisation and how to apply it to the safety assessment of a subsurface repository. (authors)

  17. Hydraulically powered dissimilar teleoperated system controller design

    International Nuclear Information System (INIS)

    Jansen, J.F.; Kress, R.L.

    1996-01-01

    This paper will address two issues associated with the implementation of a hydraulically powered dissimilar master-slave teleoperated system. These issues are the overall system control architecture and the design of robust hydraulic servo controllers for the position control problem. Finally, a discussion of overall system performance on an actual teleoperated system will be presented

  18. Characteristics of Air Entrainment in Hydraulic Jump

    Science.gov (United States)

    Albarkani, M. S. S.; Tan, L. W.; Al-Gheethi, A.

    2018-04-01

    The characteristics of hydraulic jump, especially the air entrainment within jump is still not properly understood. Therefore, the current work aimed to determine the size and number of air entrainment formed in hydraulic jump at three different Froude numbers and to obtain the relationship between Froude number with the size and number of air entrainment in hydraulic jump. Experiments of hydraulic jump were conducted in a 10 m long and 0.3 m wide Armfield S6MKII glass-sided tilting flume. Hydraulic jumps were produced by flow under sluice gate with varying Froude number. The air entrainment of the hydraulic jump was captured with a Canon Power Shot SX40 HS digital camera in video format at 24 frames per second. Three discharges have been considered, i.e. 0.010 m3/s, 0.011 m3/s, and 0.013 m3/s. For hydraulic jump formed in each discharge, 32 frames were selected for the purpose of analysing the size and number of air entrainment in hydraulic jump. The results revealed that that there is a tendency to have greater range in sizes of air bubbles as Fr1 increases. Experiments with Fr1 = 7.547. 7.707, and 7.924 shown that the number of air bubbles increases exponentially with Fr1 at a relationship of N = 1.3814 e 0.9795Fr1.

  19. Critical analysis of soil hydraulic conductivity determination using monoenergetic gamma radiation attenuation

    International Nuclear Information System (INIS)

    Portezan Filho, Otavio

    1997-01-01

    Three soil samples of different textures: LVA (red yellow latosol), LVE (dark red latosol) and LRd (dystrophic dark red latosol) were utilized for unsaturated hydraulic conductivity K(θ) measurements. Soil bulk densities and water contents during internal water drainage were measured by monoenergetic gamma radiation attenuation, using homogeneous soil columns assembled in the laboratory. The measurements were made with a collimated gamma beam of 0.003 m in diameter using a Nal(Tl) (3'' x 3 '') detector and a 137 Cs gamma source of 74 X 10 8 Bq and 661.6 KeV. Soil columns were scanned with the gamma beam from 0.01 to 0.20 m depth, in 0.01m steps, for several soil water redistribution times. The results show a great variability of the unsaturated hydraulic conductivity relation K(θ), even though homogeneous soils were used. The variability among methods is significantly smaller in relation to variability in space. The assumption of unit hydraulic gradient during redistribution of soil water utilized in the methods of Hillel, Libardi and Sisson leads to hydraulic conductivity values that increase in depth. The exponential character of the K(θ) relationship, is responsible for the difficulty of estimating soil hydraulic conductivity, which is a consequence of small variations in the porous arrangement, even in samples supposed to be homogeneous. (author)

  20. Nonlinear dynamic modeling for smart material electro-hydraulic actuator development

    Science.gov (United States)

    Larson, John P.; Dapino, Marcelo J.

    2013-03-01

    Smart material electro-hydraulic actuators use hydraulic rectification by one-way check valves to amplify the motion of smart materials, such as magnetostrictives and piezoelectrics, in order to create compact, lightweight actuators. A piston pump driven by a smart material is combined with a hydraulic cylinder to form a self-contained, power-by-wire actuator that can be used in place of a conventional hydraulic system without the need for hydraulic lines and a centralized pump. The performance of an experimental actuator driven by a 12.7 mm diameter, 114 mm length Terfenol-D rod is evaluated over a range of applied input frequencies, loads, and currents. The peak performance achieved is 37 W, moving a 220 N load at a rate of 17 cm/s and producing a blocked pressure of 12.5 MPa. Additional tests are conducted to quantify the dynamic behavior of the one-way reed valves using a scanning laser vibrometer to identify the frequency response of the reeds and the effect of the valve seat and fluid mass loading. A lumped-parameter model is developed for the system that includes valve inertia and fluid response nonlinearities, and the model results are compared with the experimental data.

  1. Hydraulic loop: practices using open control systems

    International Nuclear Information System (INIS)

    Carrasco, J.A.; Alonso, L.; Sanchez, F.

    1998-01-01

    The Tecnatom Hydraulic Loop is a dynamic training platform. It has been designed with the purpose of improving the work in teams. With this system, the student can obtain a full scope vision of a system. The hydraulic Loop is a part of the Tecnatom Maintenance Centre. The first objective of the hydraulic Loop is the instruction in components, process and process control using open control system. All the personal of an electric power plant can be trained in the Hydraulic Loop with specific courses. The development of a dynamic tool for tests previous to plant installations has been an additional objective of the Hydraulic Loop. The use of this platform is complementary to the use of full-scope simulators in order to debug and to analyse advanced control strategies. (Author)

  2. Hydraulic jumps in a channel

    DEFF Research Database (Denmark)

    Bonn, D.; Andersen, Anders Peter; Bohr, Tomas

    2009-01-01

    We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected......'s mixing-length theory with a mixing length that is proportional to the height of the fluid layer. Using averaged boundary-layer equations, taking into account the friction with the channel walls and the eddy viscosity, the flow both upstream and downstream of the jump can be understood. For the downstream...... subcritical flow, we assume that the critical height is attained close to the channel outlet. We use mass and momentum conservation to determine the position of the jump and obtain an estimate which is in rough agreement with our experiment. We show that the averaging method with a varying velocity profile...

  3. Hydraulically amplified PZT mems actuator

    Science.gov (United States)

    Miles, Robin R.

    2004-11-02

    A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

  4. Dolomitic lime containing hydraulic additive

    International Nuclear Information System (INIS)

    Lagzdina, S.; Sedmalis, U.; Bidermanis, L.; Liepins, J.; Grosvalds, I.

    1997-01-01

    To obtain qualitative dolomitic lime the optimum calcination temperature of dolomite containing about 9 % of clayey substances is 900 deg C. The mechanical strength of dolomitic lime containing 30 % of brick waste additive after 6-9 months of hardening is 1.4-1.5 times higher than that of samples without hydraulic additive, for calcium lime - 2.2-2.6 times higher. Generally the mechanical strength of dolomitic lime is higher than that one of calcium lime. It can be explained by the active role of MgO in the hydration and hardening processes of dolomitic lime. Xray diffraction phase analysis was performed by X-ray diffractometer DPON-3M with Cu-K α emission filter

  5. Experimental investigation of the dielectric properties of soil under hydraulic loading

    International Nuclear Information System (INIS)

    Bittner, Tilman; Bore, Thierry; Karlovšek, Jurij; Scheuermann, Alexander; Wagner, Norman

    2017-01-01

    An experimental set-up was developed in order to determine the coupled hydraulic, dielectric and mechanical properties of granular media under hydraulic loading. The set-up consisted of a modified column for permeability tests involving a flow meter and pressure transducers along the sample to quantify the hydraulic gradient. A newly developed open-ended coaxial probe allowed the measurement of the frequency dependent dielectric permittivity of the material under test. The shear strength of the sample within the column was measured using a conventional vane shear device. In this paper, the overall set-up is introduced with focus on the open-ended coaxial probe. The design and calibration of the probe are introduced in detail. A numerical study showed that the sensitive cylindrical volume of the probe was approximately 150 mm in diameter with a depth of 65 mm. An investigation with glass beads showed that the set-up allowed the parameterization of the hydraulic, mechanic and dielectric parameters of granular materials under the influence of vertical flow. A satisfactorily good correlation between porosity and the real part of the dielectric permittivity was detected. The critical hydraulic gradient defining the transition of a fixed bed of particles to fluidization was characterized by a sharp peak in the evolution of the hydraulic conductivity and could easily be determined from the measurements. The shear strength of the material under test reduces linearly with increasing hydraulic gradient. Future investigations will be carried out to provide the required parameterizations for experimental and numerical investigations of the internal erosion of granular media. (paper)

  6. effective hydraulic conductivity for a soil of variable pore size

    African Journals Online (AJOL)

    eobe

    Keywords: hydraulic conductivity, soil, infiltration, permeability, water. 1. INTRODUCTION. INTRODUCTION. INTRODUCTION. Accurate determination of hydraulic conductivity is very crucial for infiltration and runoff estimation. Factors which affect water infiltration in the soil include hydraulic conductivity, wetting front and soil.

  7. Thermal-hydraulic characteristics of double flat core HCLWR

    International Nuclear Information System (INIS)

    Sugimoto, Jun; Iwamura, Takamichi; Okubo, Tsutomu; Murao, Yoshio

    1989-02-01

    A thermal-hydraulic characteristics of double flat core high conversion light water reactor (HCLWR) is described. The concept of flat core proposed by Ishiguro et al. is to achieve negative void reactivity coefficient in tight lattice core, and at the same time, high conversion ratio and high burnup can be obtainable. The proposed double flat core HCLWR, based on these physical advantages and the consideration of safety assurance, aims at efficient use of the pressure vessel space to produce comparable thermal output as current 3-loop PWRs. The present work revealed the following items concerning the thermalhydraulic feasibility of the double flat core HCLWR: (1) Main thermal-hydraulic parameters of the plant can be almost the same as current PWRs, showing the use of PWR standard components without major modifications except in core region. (2) Heat removal from the fuel rod in a steady operational condition has enough margin to the critical heat flux (CHF) limit, which is evaluated with the existing CHF correlations. (3) The calculation by REFLA code shows that the maximum cladding temperature in LOCA-reflood is estimated to be far lower than the licensing criteria. It is therefore considered that the proposed double flat core HCLWR is feasible from the point of thermal-hydraulics. Since the available data base has certain applicational limit to the very short core as the present double flat core HCLWR, further detailed assessment is required. (author)

  8. Hydraulic adjustments underlying drought resistance of Pinus halepensis.

    Science.gov (United States)

    Klein, Tamir; Cohen, Shabtai; Yakir, Dan

    2011-06-01

    Drought-induced tree mortality has increased over the last decades in forests around the globe. Our objective was to investigate under controlled conditions the hydraulic adjustments underlying the observed ability of Pinus halepensis to survive seasonal drought under semi-arid conditions. One hundred 18-month saplings were exposed in the greenhouse to 10 different drought treatments, simulating combinations of intensities (fraction of water supply relative to control) and durations (period with no water supply) for 30 weeks. Stomata closed at a leaf water potential (Ψ(l)) of -2.8 MPa, suggesting isohydric stomatal regulation. In trees under extreme drought treatments, stomatal closure reduced CO(2) uptake to -1 µmol m(-2) s(-1), indicating the development of carbon starvation. A narrow hydraulic safety margin of 0.3 MPa (from stomatal closure to 50% loss of hydraulic conductivity) was observed, indicating a strategy of maximization of CO2 uptake in trees otherwise adapted to water stress. A differential effect of drought intensity and duration was observed, and was explained by a strong dependence of the water stress effect on the ratio of transpiration to evapotranspiration T/ET and the larger partitioning to transpiration associated with larger irrigation doses. Under intense or prolonged drought, the root system became the main target for biomass accumulation, taking up to 100% of the added biomass, while the stem tissue biomass decreased, associated with up to 60% reduction in xylem volume.

  9. Results From a Channel Restoration Project: Hydraulic Design Considerations

    Science.gov (United States)

    Karle, K.F.; Densmore, R.V.; ,

    2001-01-01

    Techniques for the hydraulic restoration of placer-mined streams and floodplains were developed in Denali National Park and Preserve, Alaska. The two-year study at Glen Creek focused on a design of stream and floodplain geometry using hydraulic capacity and shear stress equations. Slope and sinuosity values were based on regional relationships. Design requirements included a channel capacity for a bankfull discharge and a floodplain capacity for a 1.5- to 100-year discharge. Several bio-engineering techniques using alder and willow, including anchored brush bars, streambank hedge layering, seedlings, and cuttings, were tested to dissipate floodwater energy and encourage sediment deposition until natural revegetation stabilized the new floodplains. Permanently monumented cross-sections installed throughout the project site were surveyed every one to three years. Nine years after the project began, a summer flood caused substantial damage to the channel form, including a change in width/depth ratio, slope, and thalweg location. Many of the alder brush bars were heavily damaged or destroyed, resulting in significant bank erosion. This paper reviews the original hydraulic design process, and describes changes to the channel and floodplain geometry over time, based on nine years of cross-section surveys.

  10. Estimation of intrathoracic arterial diameter by means of computed tomographic angiography in Hispaniolan Amazon parrots.

    Science.gov (United States)

    Beaufrère, Hugues; Rodriguez, Daniel; Pariaut, Romain; Gaschen Dvm, Lorrie; Schnellbacher, Rodney; Nevarez, Javier G; Tully, Thomas N

    2011-02-01

    To establish a computed tomography (CT)-angiography protocol and measure the diameters of major arteries in parrots. 13 Hispaniolan Amazon parrots (Amazona ventralis). 16-slice CT scanning was used to measure the apparent diameter of the ascending aorta, abdominal aorta, pulmonary arteries, and brachiocephalic trunk. Before scanning, all birds underwent ECG and echocardiographic assessment and were considered free of detectable cardiovascular diseases. Each bird was anesthetized, and a precontrast helical CT scan was performed. Peak aortic enhancement was established with a test bolus technique via dynamic axial CT scan over a predetermined single slice. An additional bolus of contrast medium was then injected, and a helical CT-angiography scan was performed immediately afterward. Arterial diameter measurements were obtained by 2 observers via various windows before and after injection, and intra- and interobserver agreement was assessed. Reference limits were determined for arterial diameter measurements before and after contrast medium administration in pulmonary, mediastinal, and manual angiography windows. Ratios of vertebral body diameter to keel length were also calculated. Intraobserver agreement was high (concordance correlation coefficients ≥ 0.95); interobserver agreement was medium to high (intraclass correlation coefficients ≥ 0.65). CT-angiography was safe and is of potential diagnostic value in parrots. We recommend performing the angiography immediately after IV injection of 3 mL of iohexol/kg. Arterial diameter measurements at the described locations were reliable.

  11. Pharyngeal diameter in various head and neck positions during exercise in sport horses

    Science.gov (United States)

    2014-01-01

    Background In equine athletes, dynamic stenotic disorders of the upper airways are often the cause for abnormal respiratory noises and/or poor performance. There are hypotheses, that head and neck flexion may influence the morphology and function of the upper airway and thus could even induce or deteriorate disorders of the upper respiratory tract. Especially the pharynx, without osseous or cartilaginous support is prone to changes in pressure and airflow during exercise. The objective of this study was to develop a method for measuring the pharyngeal diameter in horses during exercise, in order to analyse whether a change of head-neck position may have an impact on the pharyngeal diameter. Results Under the assumption that the width of the epiglottis remains constant in healthy horses, the newly developed method for calculating the pharyngeal diameter in horses during exercise is unsusceptible against changes of the viewing-angle and distance between the endoscope and the structures, which are to be assessed. The quotient of the width of the epiglottis and the perpendicular from a fixed point on the dorsal pharynx to the epiglottis could be used to determine the pharyngeal diameter. The percentage change of this quotient (pharynx-epiglottis-ratio; PE-ratio) in the unrestrained head-neck position against the reference position was significantly larger than that of any other combination of the head-neck positions investigated. A relation between the percentage change in PE-ratio and the degree of head and neck flexion could not be confirmed. Conclusions It could be shown, that the pharyngeal diameter is reduced through the contact position implemented by the rider in comparison to the unrestrained head and neck position. An alteration of the pharyngeal diameter depending on the degree of head and neck flexion (represented by ground and withers angle) could not be confirmed. PMID:24886465

  12. The effects of axis ratio on laminar fluid flow around an elliptical cylinder

    International Nuclear Information System (INIS)

    Faruquee, Zakir; Ting, David S-K.; Fartaj, Amir; Barron, Ronald M.; Carriveau, Rupp

    2007-01-01

    An elliptical cylinder is a generic shape which represents a flat plate at its minor to major axis ratio (AR) limits of zero and infinity, and a circular cylinder at AR of unity. While incompressible flows over a streamwise flat plate (AR = 0), a cross-stream flat plate (AR = ∞), and a circular cylinder have been studied extensively, the role of AR on the detailed flow structure is still not well understood. Therefore, a numerical study was conducted to examine the flow field around an elliptical cylinder over a range of ARs from 0.3 to 1, with the major axis parallel to the free-stream, at a Reynolds number of 40 based on the hydraulic diameter. The control volume approach of FLUENT was used to solve the fluid flow equations, assuming the flow over the cylinder is unbounded, steady, incompressible and two-dimensional. It has been found that a pair of steady vortices forms when AR reaches a critical value of 0.34; below this value no vortices are formed behind the elliptical cylinder. Various wake parameters, drag coefficient, pressure and velocity distributions, have been characterized as functions of AR. The wake size and the drag coefficient are found to increase with the increase of AR. Quadratic correlations have been obtained to describe the relations of wake length and drag coefficient with axis ratio

  13. Thermal-hydraulic modeling of porous bed reactors

    International Nuclear Information System (INIS)

    Araj, K.J.; Nourbakhsh, H.P.

    1987-01-01

    Optimum design of nuclear reactor cores requires an iterative approach between the thermal-hydraulic, neutronic, and operational analysis. This paper will concentrate on the thermal-hydraulic behavior of a hydrogen-cooled small particle bed reactor (PBR). The PBR core modeled here consists of a hexagonal array of fuel elements embedded in a moderator matrix. The fuel elements are annular packed beds of fuel particles held between two porous cylindrical frits. These particles, 500 to 600 μm in diameter, have a uranium carbide core, which is coated by two layers of graphite and an outer coating of zirconium carbide. Coolant flows, radially inward, from the cold frit through the packed bed and hot frit and axially out the channel, formed by the hot frit to a common plenum. A fast running one-dimensional lumped-parameter steady-state code (FTHP) was developed to evaluate the effects of design changes in fuel assembly and power distribution. Another objective for the code was to investigate various methods of coolant control to minimize hot channel effects and maximize outlet temperatures

  14. Wiener Index, Diameter, and Stretch Factor of a Weighted Planar Graph in Subquadratic Time

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    over all pairs of distinct vertices of the ratio between the graph distance and the Euclidean distance between the two vertices). More specifically, we show that the Wiener index and diameter can be found in O(n^2*(log log n)^4/log n) worst-case time and that the stretch factor can be found in O(n^2......We solve three open problems: the existence of subquadratic time algorithms for computing the Wiener index (sum of APSP distances) and the diameter (maximum distance between any vertex pair) of a planar graph with non-negative edge weights and the stretch factor of a plane geometric graph (maximum...

  15. The use of small diameter probing equipment for contaminated site investigation

    International Nuclear Information System (INIS)

    Christy, T.M.; Spradlin, S.C.

    1992-01-01

    The past decade has witnessed a dramatic increase in the number of contaminated sites being investigated in the United States. This increase in subsurface investigation has spurred a corresponding increase in the development of subsurface sampling tools and methods. The past five years, in particular, have seen the development of small diameter (1 double-prime to 1.4 double-prime O.D.) percussion driven probing tools which can be used for the recovery of soil vapor, soil core and groundwater samples. This development has placed heretofore unavailable tools at the disposal of site investigators. Mechanized, vehicle mounted soil probe systems apply both static force and hydraulically powered percussion hammers for tool placement. Static down forces up to 3,000 lbs combined with percussion hammers of eight (8) horsepower continuous output are typical on equipment available to the field investigator. Using these energies, probing tools have been used for sampling a variety of media at depths exceeding 70 feet. Advantages of probing equipment which have contributed to its increasing usage in recent years include: ease of mobilization, absence of borehole cuttings, minimization of surface disturbance, and speed of sample collection. This paper focuses on the field application of hydraulic probing equipment including: the suitability of probing operations with respect to various Boil types and lithologies to probing operations; sampler types and recovery quantities for various media, and innovative probing applications presently being tested

  16. Thermal-hydraulic unreliability of passive systems

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Saltos, N.T.

    1995-01-01

    Advanced light water reactor designs like AP600 and the simplified boiling water reactor (SBWR) use passive safety systems for accident prevention and mitigation. Because these systems rely on natural forces for their operation, their unavailability due to hardware failures and human error is significantly smaller than that of active systems. However, the coolant flows predicted to be delivered by these systems can be subject to significant uncertainties, which in turn can lead to a significant uncertainty in the predicted thermal-hydraulic performance of the plant under accident conditions. Because of these uncertainties, there is a probability that an accident sequence for which a best estimate thermal-hydraulic analysis predicts no core damage (success sequence) may actually lead to core damage. For brevity, this probability will be called thermal-hydraulic unreliability. The assessment of this unreliability for all the success sequences requires very expensive computations. Moreover, the computational cost increases drastically as the required thermal-hydraulic reliability increases. The required computational effort can be greatly reduced if a bounding approach can be used that either eliminates the need to compute thermal-hydraulic unreliabilities, or it leads to the analysis of a few bounding sequences for which the required thermal-hydraulic reliability is relatively small. The objective of this paper is to present such an approach and determine the order of magnitude of the thermal-hydraulic unreliabilities that may have to be computed

  17. Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

    Science.gov (United States)

    Christoffersen, Bradley O.; Gloor, Manuel; Fauset, Sophie; Fyllas, Nikolaos M.; Galbraith, David R.; Baker, Timothy R.; Kruijt, Bart; Rowland, Lucy; Fisher, Rosie A.; Binks, Oliver J.; Sevanto, Sanna; Xu, Chonggang; Jansen, Steven; Choat, Brendan; Mencuccini, Maurizio; McDowell, Nate G.; Meir, Patrick

    2016-11-01

    Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ɛ, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs), and the leaf : sapwood area ratio Al : As). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity (Amax), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait-trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model predictions. The plant

  18. Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro

    Directory of Open Access Journals (Sweden)

    B. O. Christoffersen

    2016-11-01

    Full Text Available Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ε, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x and stomata (P50,gs, and the leaf : sapwood area ratio Al : As. We embedded this plant hydraulics model within a trait forest simulator (TFS that models light environments of individual trees and their upper boundary conditions (transpiration, as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD, leaf mass per area (LMA, and photosynthetic capacity (Amax, and evaluated the coupled model (called TFS v.1-Hydro predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model

  19. Response time verification of in situ hydraulic pressure sensors in a nuclear reactor

    International Nuclear Information System (INIS)

    Foster, C.G.

    1978-01-01

    A method and apparatus for verifying response time in situ of hydraulic pressure and pressure differential sensing instrumentation in a nuclear circuit is disclosed. Hydraulic pressure at a reference sensor and at an in situ process sensor under test is varied according to a linear ramp. Sensor response time is then determined by comparison of the sensor electrical analog output signals. The process sensor is subjected to a relatively slowly changing and a relatively rapidly changing hydraulic pressure ramp signal to determine an upper bound for process sensor response time over the range of all pressure transients to which the sensor is required to respond. Signal linearity is independent of the volumetric displacement of the process sensor. The hydraulic signal generator includes a first pressurizable gas reservoir, a second pressurizable liquid and gas reservoir, a gate for rapidly opening a gas communication path between the two reservoirs, a throttle valve for regulating rate of gas pressure equalization between the two reservoirs, and hydraulic conduit means for simultaneously communicating a ramp of hydraulic pressure change between the liquid/gas reservoir and both a reference and a process sensor. By maintaining a sufficient pressure differential between the reservoirs and by maintaining a sufficient ratio of gas to liquid in the liquid/gas reservoir, excellent linearity and minimal transient effects can be achieved for all pressure ranges, magnitudes, and rates of change of interest

  20. Quantitative experiments on thermal hydraulic characteristics of an annular tube with twisted fins

    International Nuclear Information System (INIS)

    Ezato, Koichiro; Dairaku, Masayuki; Taniguchi, Masaki; Sato, Kazuyoshi; Suzuki, Satoshi; Akiba, Masato

    2003-11-01

    Thermal hydraulic experiments measuring critical heat flux (CHF) and pressure drop of an annular tube with twisted fins, ''annular swirl tube'', has been performed to examine its applicability to the ITER divertor cooling structure. The annular swirl tube consists of two concentric circular tubes, the outer and inner tubes. The outer tube with outer and inner diameters (OD and ID) of 21 mm and 15 mm is made of Cu-alloy that is CuCrZr and oe of candidate materials of the ITER divertor cooling tube. The inner tube with OD of 11 mm and ID of 9 mm is made of stainless steal. It has an external swirl fin with twist ratio (y) of three to enhance its heat transfer performance. In this tube, cooling water flows inside of the inner tube first, and then returns into an annulus between the outer and inner tubes with a swirl flow at an end-return of the cooling tube. The CHF experiments show that no degradation of CHF of the annular swirl tube in comparison with the conventional swirl tube whose dimensions are similar to those of the outer tube of the annular swirl tube. A minimum axial velocity of 7.1 m/s is required to remove the incident heat flux of 28MW/m 2 , the ITER design value. Applicability of the JAERI's correlation for the heat transfer to the annular swirl tube is also demonstrated by comparing the experimental results with those of the numerical analysis. The friction factor correlation for the annular flow with the twisted fins is also proposed for the hydrodynamic design of the ITER vertical target. The least pressure drop at the end-return is obtained by using the hemispherical end-plug. Its radius is the same as that of ID of the outer cooling tube. These results show that thermal-hydraulic performance of the annular swirl tube is promising in application to the cooling structure for the ITER vertical target. (author)

  1. Water transport through tall trees: A vertically-explicit, analytical model of xylem hydraulic conductance in stems.

    Science.gov (United States)

    Couvreur, Valentin; Ledder, Glenn; Manzoni, Stefano; Way, Danielle A; Muller, Erik B; Russo, Sabrina E

    2018-05-08

    Trees grow by vertically extending their stems, so accurate stem hydraulic models are fundamental to understanding the hydraulic challenges faced by tall trees. Using a literature survey, we showed that many tree species exhibit continuous vertical variation in hydraulic traits. To examine the effects of this variation on hydraulic function, we developed a spatially-explicit, analytical water transport model for stems. Our model allows Huber ratio, stem-saturated conductivity, pressure at 50% loss of conductivity, leaf area, and transpiration rate to vary continuously along the hydraulic path. Predictions from our model differ from a matric flux potential model parameterized with uniform traits. Analyses show that cavitation is a whole-stem emergent property resulting from nonlinear pressure-conductivity feedbacks that, with gravity, cause impaired water transport to accumulate along the path. Because of the compounding effects of vertical trait variation on hydraulic function, growing proportionally more sapwood and building tapered xylem with height, as well as reducing xylem vulnerability only at branch tips while maintaining transport capacity at the stem base, can compensate for these effects. We therefore conclude that the adaptive significance of vertical variation in stem hydraulic traits is to allow trees to grow tall and tolerate operating near their hydraulic limits. This article is protected by copyright. All rights reserved.

  2. Hydraulic Fracturing and the Environment

    Science.gov (United States)

    Ayatollahy Tafti, T.; Aminzadeh, F.; Jafarpour, B.; de Barros, F.

    2013-12-01

    In this presentation, we highlight two key environmental concerns of hydraulic fracturing (HF), namely induced seismicity and groundwater contamination (GC). We examine the induced seismicity (IS) associated with different subsurface fluid injection and production (SFIP) operations and the key operational parameters of SFIP impacting it. In addition we review the key potential sources for possible water contamination. Both in the case of IS and GC we propose modeling and data analysis methods to quantify the risk factors to be used for monitoring and risk reduction. SFIP include presents a risk in hydraulic fracturing, waste water injection, enhanced oil recovery as well as geothermal energy operations. Although a recent report (NRC 2012) documents that HF is not responsible for most of the induced seismicities, we primarily focus on HF here. We look into vaious operational parameters such as volume and rate of water injection, the direction of the well versus the natural fracture network, the depth of the target and the local stress field and fault system, as well as other geological features. The latter would determine the potential for triggering tectonic related events by small induced seismicity events. We provide the building blocks for IS risk assessment and monitoring. The system we propose will involve adequate layers of complexity based on mapped seismic attributes as well as results from ANN and probabilistic predictive modeling workflows. This leads to a set of guidelines which further defines 'safe operating conditions' and 'safe operating zones' which will be a valuable reference for future SFIP operations. We also illustrate how HF can lead to groundwater aquifer contamination. The source of aquifer contamination can be the hydrocarbon gas or the chemicals used in the injected liquid in the formation. We explore possible pathways of contamination within and discuss the likelihood of contamination from each source. Many of the chemical compounds used

  3. Hydraulic fracturing of rock-fill dam

    Directory of Open Access Journals (Sweden)

    Jun-Jie WANG

    2016-02-01

    Full Text Available The condition in which hydraulic fracturing in core of earth-rock fill dam maybe induced, the mechanism by which the reason of hydraulic fracturing canbe explained, and the failure criterion by which the occurrence of hydraulicfracturing can be determined, were investigated. The condition dependson material properties such as, cracks in the core and low permeability ofcore soil, and “water wedging” action in cracks. An unsaturated core soiland fast impounding are the prerequisites for the formation of “waterwedging” action. The mechanism of hydraulic fracturing can be explainedby fracture mechanics. The crack propagation induced by water pressuremay follow any of mode I, mode II and mixed mode I-II. Based on testingresults of a core soil, a new criterion for hydraulic fracturing was suggested,from which mechanisms of hydraulic fracturing in the core of rock-fill damwere discussed. The results indicated that factors such as angle betweencrack surface and direction of principal stress, local stress state at thecrack, and fracture toughness KIC of core soil may largely affect theinduction of hydraulic fracturing and the mode of the propagation of thecrack.The condition in which hydraulic fracturing in core of earth-rock fill dam maybe induced, the mechanism by which the reason of hydraulic fracturing canbe explained, and the failure criterion by which the occurrence of hydraulicfracturing can be determined, were investigated. The condition dependson material properties such as, cracks in the core and low permeability ofcore soil, and “water wedging” action in cracks. An unsaturated core soiland fast impounding are the prerequisites for the formation of “waterwedging” action. The mechanism of hydraulic fracturing can be explainedby fracture mechanics. The crack propagation induced by water pressuremay follow any of mode I, mode II and mixed mode I-II. Based on testingresults of a core soil, a new criterion for hydraulic fracturing

  4. DESIGN AND CONSTRUCTION OF A HYDRAULIC PISTON

    OpenAIRE

    Santos De la Cruz, Eulogio; Rojas Lazo, Oswaldo; Yenque Dedios, Julio; Lavado Soto, Aurelio

    2014-01-01

    A hydraulic system project includes the design, materials selection and construction of the hydraulic piston, hydraulic circuit and the joint with the pump and its accesories. This equiment will be driven by the force of moving fluid, whose application is in the devices of machines, tools, printing, perforation, packing and others. El proyecto de un sistema hidráulico, comprende el diseño, selección de materiales y construcción del pistón hidráulico, circuito hidráulico y el ensamble con l...

  5. Experimental thermal hydraulics in support of FBR

    International Nuclear Information System (INIS)

    Padmakumar, G.; Anand Babu, C.; Kalyanasundaram, P.; Vaidyanathan, G.

    2009-01-01

    The thermal hydraulic design plays a crucial role for the safe and economical deployment of Liquid Metal Cooled Fast Breeder Reactor (LMFBR). Robust experimental programmes are required in support of LMFBR thermal hydraulics design. The philosophy of testing has been to construct small scale models to understand the physical behaviour and to build larger scale models to optimize the component design. The experiments are conducted either in sodium or using a simulant like water/air. The paper gives a brief account of the various thermal hydraulic experiments carried out in support of the design of Prototype Fast Breeder Reactor (PFBR). (author)

  6. Carbofuran biodegradation in brackish groundwater and its effect on the hydraulic properties of the porous medium

    Science.gov (United States)

    Amiaz, Yanai; Ronen, Zeev; Adar, Eilon; Weisbrod, Noam

    2015-04-01

    A chalk fractured aquitard beneath an industrial site is subjected to intense contamination due to percolation of contaminants from the different facilities operating at the site. In order to reduce further contamination, draining trenches were excavated and filled with coarse gravel (3-4 cm in diameter) forming a porous medium, to which the contaminated groundwater discharges from the fractures surrounding the trenches. This research is aimed at establishing a biodegrading process of high efficiency and performance within the draining trenches. The research includes both field and laboratory experiments. An experimental setup of five columns (50 cm length and 4.5 cm in diameter) was constructed under highly controlled conditions. Over the course of the experiments, the columns were filled with different particle sizes and placed in a temperature controlled chamber. Filtered groundwater (0.2 µm) from the site groundwater, enriched by a model contaminant carbofuran (CRF), was injected to the columns; as two of the columns were inoculated by CRF degrading microorganisms native in the site's groundwater, two columns were inoculated by CRF degrading bacteria from the external environment, and one column was used as a control. During the experiment, measurements were taken from different locations along each column. These include: (a) CRF concentration and (b) hydraulic pressure and solution viscosity (in order to obtain the changes in permeability). A tracer test using uranine was carried out in parallel, in order to obtain the changes in hydraulic parameters. Correlating CRF concentration variations to changes of hydraulic parameters enable the deduction due to the effect that biological activity (under different temperature regimes) has on the hydraulic properties of the porous medium and its effect on the process of contaminant groundwater bodies' remediation. Preliminary results suggest that although biodegradation occurs, microbial activity has minor effect on

  7. Estimating biozone hydraulic conductivity in wastewater soil-infiltration systems using inverse numerical modeling.

    Science.gov (United States)

    Bumgarner, Johnathan R; McCray, John E

    2007-06-01

    During operation of an onsite wastewater treatment system, a low-permeability biozone develops at the infiltrative surface (IS) during application of wastewater to soil. Inverse numerical-model simulations were used to estimate the biozone saturated hydraulic conductivity (K(biozone)) under variably saturated conditions for 29 wastewater infiltration test cells installed in a sandy loam field soil. Test cells employed two loading rates (4 and 8cm/day) and 3 IS designs: open chamber, gravel, and synthetic bundles. The ratio of K(biozone) to the saturated hydraulic conductivity of the natural soil (K(s)) was used to quantify the reductions in the IS hydraulic conductivity. A smaller value of K(biozone)/K(s,) reflects a greater reduction in hydraulic conductivity. The IS hydraulic conductivity was reduced by 1-3 orders of magnitude. The reduction in IS hydraulic conductivity was primarily influenced by wastewater loading rate and IS type and not by the K(s) of the native soil. The higher loading rate yielded greater reductions in IS hydraulic conductivity than the lower loading rate for bundle and gravel cells, but the difference was not statistically significant for chamber cells. Bundle and gravel cells exhibited a greater reduction in IS hydraulic conductivity than chamber cells at the higher loading rates, while the difference between gravel and bundle systems was not statistically significant. At the lower rate, bundle cells exhibited generally lower K(biozone)/K(s) values, but not at a statistically significant level, while gravel and chamber cells were statistically similar. Gravel cells exhibited the greatest variability in measured values, which may complicate design efforts based on K(biozone) evaluations for these systems. These results suggest that chamber systems may provide for a more robust design, particularly for high or variable wastewater infiltration rates.

  8. Investigation on the effect of seawater to hydraulic property and wetting process of bentonite

    International Nuclear Information System (INIS)

    Hasegawa, Takuma

    2004-01-01

    On high-level waste disposal, bentonite is one of the most promising material for buffer and backfill material. The hydraulic properties and wetting process of bentonite are important not only for barrier performance assessment but also for prediction of waste disposal environment, such as resaturation time and thermal distribution. In Japan, we should consider the effect of seawater for bentonite, because radioactive waste will be disposed of in coastal area and in marine sediment where seawater remained. However, it is not enough to understand the effect of seawater. Therefore, experimental study was conducted to investigate the effect of seawater on the hydraulic conductivity and wetting process of bentonite. The effect of seawater on hydraulic conductivity is significant for Na-bentonite, the hydraulic conductivity of Na-bentonite in seawater is one order to magnitude higher than that in distilled water. On the other hand, the hydraulic conductivity of Ca-bentonite is not influenced by seawater. The hydraulic conductivity of bentonite decreases as effective montmorillonite density increases. The effective montmorillonite density is ratio between the weight of montmorillonite and volume of porosity and montmorillonite. The hydraulic conductivity of bentonite is close related to swelling property since the hydraulic conductivity decrease as the swelling pressure increase. Wetting process of compacted bentonite could be evaluated by diffusion phenomena since infiltration rate and change of saturation rate and represented by diffusion equation. The effect of seawater on water diffusivity is significant for Na-type bentonite with low effective montmorillonite density. Except for that condition, the water diffusivity of bentonite is almost constant and is not influenced by effective montmorillonite density and seawater. (author)

  9. [Seasonal differences in the leaf hydraulic conductance of mature Acacia mangium in response to its leaf water use and photosynthesis].

    Science.gov (United States)

    Zhao, Ping; Sun, Gu-Chou; Ni, Guang-Yan; Zeng, Xiao-Ping

    2013-01-01

    In this study, measurements were made on the leaf water potential (psi1), stomatal conductance (g(s)), transpiration rate, leaf area index, and sapwood area of mature Acacia mangium, aimed to understand the relationships of the leaf hydraulic conductance (K1) with the leaf water use and photosynthetic characteristics of the A. mangium in wet season (May) and dry season (November). The ratio of sapwood area to leaf area (A(sp)/A(cl)) of the larger trees with an average height of 20 m and a diameter at breast height (DBH) of 0.26 m was 8.5% higher than that of the smaller trees with an average height of 14.5 m and a DBH of 0.19 m, suggesting that the larger trees had a higher water flux in their leaf xylem, which facilitated the water use of canopy leaf. The analysis on the vulnerability curve of the xylem showed that when the K1 decreased by 50%, the psi1 in wet season and dry season was -1.41 and -1.55 MPa, respectively, and the vulnerability of the xylem cavitation was higher in dry season than in wet season. The K1 peak value in wet season and dry season was 5.5 and 4.5 mmol x m(-2) x s(-1) x MPa(-1), and the maximum transpiration rate (T(r max)) was 3.6 and 1.8 mmol x m(-2) x s(-1), respectively. Both the K1 and T(r max), were obviously higher in wet season than in dry season. Within a day, the K1 and T(r), fluctuated many times, reflecting the reciprocated cycle of the xylem cavitation and refilling. The leaf stomatal closure occurred when the K1 declined over 50% or the psi1 reached -1.6 MPa. The g(s) would be maintained at a high level till the K1 declined over 50%. The correlation between the hydraulic conductance and photosynthetic rate was more significant in dry season than in wet season. The loss of leaf hydraulic conductance induced by seasonal change could be the causes of the decrease of T(r) and CO2 gas exchange.

  10. Model-based servo hydraulic control of a continuously variable transmission

    NARCIS (Netherlands)

    Cools, S.J.M.; Veenhuizen, P.A.; Pauwelussen, J.P.

    2004-01-01

    In order to reduce the power consumption of a transmission, maximum tracking accuracy should be achieved of both ratio and pressures in the variator. A control strategy is proposed to steer a variator, actuated with a newly developed hydraulic system, of a Continuously Variable Transmission (CVT).

  11. Parker Hybrid Hydraulic Drivetrain Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Collett, Raymond [Parker-Hannifin Corporation, Cleveland, OH (United States); Howland, James [Parker-Hannifin Corporation, Cleveland, OH (United States); Venkiteswaran, Prasad [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2014-03-31

    This report examines the benefits of Parker Hannifin hydraulic hybrid brake energy recovery systems used in commercial applications for vocational purposes. A detailed background on the problem statement being addressed as well as the solution set specific for parcel delivery will be provided. Objectives of the demonstration performed in high start & stop applications included opportunities in fuel usage reduction, emissions reduction, vehicle productivity, and vehicle maintenance. Completed findings during the demonstration period and parallel investigations with NREL, CALSTART, along with a literature review will be provided herein on this research area. Lastly, results identified in the study by third parties validated the savings potential in fuel reduction of on average of 19% to 52% over the baseline in terms of mpg (Lammert, 2014, p11), Parker data for parcel delivery vehicles in the field parallels this at a range of 35% - 50%, emissions reduction of 17.4% lower CO2 per mile and 30.4% lower NOx per mile (Gallo, 2014, p15), with maintenance improvement in the areas of brake and starter replacement, while leaving room for further study in the area of productivity in terms of specific metrics that can be applied and studied.

  12. Cavitation instabilities in hydraulic machines

    International Nuclear Information System (INIS)

    Tsujimoto, Y

    2013-01-01

    Cavitation instabilities in hydraulic machines, hydro turbines and turbopump inducers, are reviewed focusing on the cause of instabilities. One-dimensional model of hydro turbine system shows that the overload surge is caused by the diffuser effect of the draft tube. Experiments show that this effect also causes the surge mode oscillations at part load. One dimensional model of a cavitating turbopump inducer shows that the mass flow gain factor, representing the cavity volume increase caused by the incidence angle increase is the cause of cavitation surge and rotating cavitation. Two dimensional model of a cavitating turbopump inducer shows that various modes of cavitation instabilities start to occur when the cavity length becomes about 65% of the blade spacing. This is caused by the interaction of the local flow near the cavity trailing edge with the leading edge of the next blade. It was shown by a 3D CFD that this is true also for real cases with tip cavitation. In all cases, it was shown that cavitation instabilities are caused by the fundamental characteristics of cavities that the cavity volume increases with the decrease of ambient pressure or the increase of the incidence angle

  13. Kuala Kemaman hydraulic model study

    International Nuclear Information System (INIS)

    Abdul Kadir Ishak

    2005-01-01

    There The problems facing the area of Kuala Kemaman are siltation and erosion at shoreline. The objectives of study are to assess the best alignment of the groyne alignment, to ascertain the most stable shoreline regime and to investigate structural measures to overcome the erosion. The scope of study are data collection, wave analysis, hydrodynamic simulation and sediment transport simulation. Numerical models MIKE 21 are used - MIKE 21 NSW, for wind-wave model, which describes the growth, decay and transformation of wind-generated waves and swell in nearshore areas. The study takes into account effects of refraction and shoaling due to varying depth, energy dissipation due to bottom friction and wave breaking, MIKE 21 HD - modelling system for 2D free-surface flow which to stimulate the hydraulics phenomena in estuaries, coastal areas and seas. Predicted tidal elevation and waves (radiation stresses) are considered into study while wind is not considered. MIKE 21 ST - the system that calculates the rates of non-cohesive (sand) sediment transport for both pure content and combined waves and current situation

  14. Flume Experiments for Optimizing the Hydraulic Performance of a Deep-Water Wetland Utilizing Emergent Vegetation and Obstructions

    Directory of Open Access Journals (Sweden)

    Shang-Shu Shih

    2016-06-01

    Full Text Available Constructed ponds and wetlands are widely used in urban areas for stormwater management, ecological conservation, and pollution treatment. The treatment efficiency of these systems is strongly related to the hydrodynamics and hydraulic residence time. In this study, we developed a physical model and used rhodamine-WT as a tracer to conduct flume experiments. An equivalent Reynolds number was assumed, and the flume was a 1/25-scale model. Emergent obstructions (EOs, submerged obstructions (SOs, and high- and low-density emergent vegetation were placed along the sides of the flume, and 49 tracer tests were performed. We altered the density, spatial extent, aspect ratio, and configurations of the obstructions and emergent vegetation to observe changes in the hydraulic efficiency of a deep-water wetland. In the cases of low-aspect-ratio obstructions, the effects of the EOs on the hydraulic efficiency were significantly stronger than those of the SOs. In contrast, in the cases of high-aspect-ratio obstructions, the improvement effects of the EOs were weaker than those of the SOs. The high-aspect-ratio EOs altered the flow direction and constrained the water conveyance area, which apparently caused a short-circuited flow phenomenon, resulting in a decrease in hydraulic efficiency. Most cases revealed that the emergent vegetation improved the hydraulic efficiency more than the EOs. The high-density emergent vegetation (HEV improved the hydraulic efficiency more than the low-density emergent vegetation (LEV. Three cases involving HEV, two cases involving LEV, and one case involving EOs attained a good hydraulic efficiency (λ > 0.75. To achieve greater water purification, aquatic planting in constructed wetlands should not be overly dense. The HEV configuration in case 3-1 achieved optimum hydraulic performance for compliance with applicable water treatment standards.

  15. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    International Nuclear Information System (INIS)

    Kim, Hyo-gon; Han, Changsoo; Lee, Jong-won; Park, Sangdeok

    2015-01-01

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program

  16. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-gon; Han, Changsoo [Hanyang University, Seoul (Korea, Republic of); Lee, Jong-won [Korea University of Science and Technology, Seoul (Korea, Republic of); Park, Sangdeok [Korea Institute of Industrial Technology, Seoul (Korea, Republic of)

    2015-02-15

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

  17. Spectroscopic study of the diameter distribution of B-doped single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Soria, G.; Pichler, T.; Ayala, P. [University of Vienna, Faculty of Physics, 1090 Vienna (Austria); Daothong, S. [Chiang Mai University, Faculty of Science, 50200 Chiang Mai (Thailand)

    2012-12-15

    In this paper, we report on the diameter distribution of boron-doped single-walled carbon nanotubes grown from triethyl borate with high vacuum chemical vapor deposition, using multi-frequency Raman resonance spectroscopy. The nanotube yield is higher than in previously reported material produced with the same method. Our results suggest that the amount of as-grown material and the range of diameters are directly correlated with feedstock used in the synthesis. The I{sub D}/I{sub G} ratio shows that the morphology of the samples is critically affected by the temperature. The population of diameters in the optimal conditions shows a Poisson distribution with a mean value at {proportional_to}1.15 nm. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Advanced Hydraulic Studies on Enhancing Particle Removal

    DEFF Research Database (Denmark)

    He, Cheng

    clarifier. The inlet zone of an existing rectangular storm water clarifier was redesigned to improve the fluid flow conditions and reduce the hydraulic head loss in order to remove the lamellar plates and adapt the clarifier to the needs of high-rate clarification of storm water with flocculant addition...... excessive local head losses and helped to select structural changes to reduce such losses. The analysis of the facility showed that with respect to hydraulic operation, the facility is a complex, highly non-linear hydraulic system. Within the existing constraints, a few structural changes examined......The removal of suspended solids and attached pollutants is one of the main treatment processes in wastewater treatment. This thesis presents studies on the hydraulic conditions of various particle removal facilities for possible ways to increase their treatment capacity and performance by utilizing...

  19. Lower Monumental Spillway Hydraulic Model Study

    National Research Council Canada - National Science Library

    Wilhelms, Steven

    2003-01-01

    A 1:40 Froudian Scale model was used to investigate the hydraulic performance of the Lower Monumental Dam spillway, stilling basin, and tailrace for dissolved gas reduction and stilling basin apron scour...

  20. Toxicity Assessment for EPA's Hydraulic Fracturing Study

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset contains data used to develop multiple manuscripts on the toxicity of chemicals associated with the hydraulic fracturing industry. These manuscripts...

  1. Hydraulic fracturing chemicals and fluids technology

    CERN Document Server

    Fink, Johannes

    2013-01-01

    When classifying fracturing fluids and their additives, it is important that production, operation, and completion engineers understand which chemical should be utilized in different well environments. A user's guide to the many chemicals and chemical additives used in hydraulic fracturing operations, Hydraulic Fracturing Chemicals and Fluids Technology provides an easy-to-use manual to create fluid formulations that will meet project-specific needs while protecting the environment and the life of the well. Fink creates a concise and comprehensive reference that enables the engineer to logically select and use the appropriate chemicals on any hydraulic fracturing job. The first book devoted entirely to hydraulic fracturing chemicals, Fink eliminates the guesswork so the engineer can select the best chemicals needed on the job while providing the best protection for the well, workers and environment. Pinpoints the specific compounds used in any given fracturing operation Provides a systematic approach to class...

  2. Pneumatic and hydraulic microactuators: a review

    International Nuclear Information System (INIS)

    De Volder, Michaël; Reynaerts, Dominiek

    2010-01-01

    The development of MEMS actuators is rapidly evolving and continuously new progress in terms of efficiency, power and force output is reported. Pneumatic and hydraulic are an interesting class of microactuators that are easily overlooked. Despite the 20 years of research, and hundreds of publications on this topic, these actuators are only popular in microfluidic systems. In other MEMS applications, pneumatic and hydraulic actuators are rare in comparison with electrostatic, thermal or piezo-electric actuators. However, several studies have shown that hydraulic and pneumatic actuators deliver among the highest force and power densities at microscale. It is believed that this asset is particularly important in modern industrial and medical microsystems, and therefore, pneumatic and hydraulic actuators could start playing an increasingly important role. This paper shows an in-depth overview of the developments in this field ranging from the classic inflatable membrane actuators to more complex piston–cylinder and drag-based microdevices. (topical review)

  3. National Laboratory of Hydraulics. 1996 progress report

    International Nuclear Information System (INIS)

    1996-01-01

    This progress report of the National Laboratory of Hydraulics (LNH) of Electricite de France (EdF) summarizes, first, the research and development studies carried out in 1996 for the development of research tools for industrial fluid mechanics and environmental hydraulics and for the development of computer tools (computer codes and softwares for fluid mechanics modeling, modeling of reactive, compressible, two-phase and turbulent flows and of complex chemical kinetics using finite elements and finite volume methods). A second parts describes the research studies performed for other services of EdF, concerning: the functioning of nuclear reactors (thermohydraulic studies of the reactor vessel and of the primary coolant circuit, gas flows following severe accidents, fluid-structure thermal coupling etc...), fossil fuel power plants, the equipment and operation of thermal power plants and hydraulic power plants, the use of electric power. A third part summarizes the river and marine hydraulic studies carried out for other companies. (J.S.)

  4. Transputer Control of Hydraulic Actuators and Robots

    DEFF Research Database (Denmark)

    Conrad, Finn

    1996-01-01

    Results from a Danish mechatronics research program entitled IMCIA - Intelligent Control and Intelligent Actuators. The objective is development of intelligent actuators for intelligent motion control. A mechatronics test facility with a transputer controlled hydraulic robot suiteable for real...

  5. Orthogonal optimization of a water hydraulic pilot-operated pressure-reducing valve

    Science.gov (United States)

    Mao, Xuyao; Wu, Chao; Li, Bin; Wu, Di

    2017-12-01

    In order to optimize the comprehensive characteristics of a water hydraulic pilot-operated pressure-reducing valve, numerical orthogonal experimental design was adopted. Six parameters of the valve, containing diameters of damping plugs, volume of spring chamber, half cone angle of main spool, half cone angle of pilot spool, mass of main spool and diameter of main spool, were selected as the orthogonal factors, and each factor has five different levels. An index of flowrate stability, pressure stability and pressure overstrike stability (iFPOS) was used to judge the merit of each orthogonal attempt. Embedded orthogonal process turned up and a final optimal combination of these parameters was obtained after totally 50 numerical orthogonal experiments. iFPOS could be low to a fairly low value which meant that the valve could have much better stabilities. During the optimization, it was also found the diameters of damping plugs and main spool played important roles in stability characteristics of the valve.

  6. Brain Arterial Diameters as a Risk Factor for Vascular Events

    OpenAIRE

    Gutierrez, Jose; Cheung, Ken; Bagci, Ahmet; Rundek, Tatjana; Alperin, Noam; Sacco, Ralph L; Wright, Clinton B; Elkind, Mitchell S V

    2015-01-01

    Background Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events. Methods and Results Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, ca...

  7. Hydraulic concrete composition and properties control system

    OpenAIRE

    PSHINKO O.M.; KRASNYUK A.V.; HROMOVA O.V.

    2015-01-01

    Purpose. Scientific work aims at the development and testing of information system to meet the challenges of concrete composition design and control (for railway structures and buildings) based on the physico-analytical method algorithm for hydraulic concrete composition calculation. Methodology. The proposed algorithm of hydraulic concrete composition calculation is based on the physicochemical mechanics and in particular on the rheology of elastic–viscous–plastic bodies. The system of canon...

  8. Multimodel Robust Control for Hydraulic Turbine

    OpenAIRE

    Osuský, Jakub; Števo, Stanislav

    2014-01-01

    The paper deals with the multimodel and robust control system design and their combination based on M-Δ structure. Controller design will be done in the frequency domain with nominal performance specified by phase margin. Hydraulic turbine model is analyzed as system with unstructured uncertainty, and robust stability condition is included in controller design. Multimodel and robust control approaches are presented in detail on hydraulic turbine model. Control design approaches are compared a...

  9. Data Analytics of Hydraulic Fracturing Data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jovan Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Viswanathan, Hari [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffery [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Middleton, Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-11

    These are a set of slides on the data analytics of hydraulic fracturing data. The conclusions from this research are the following: they proposed a permeability evolution as a new mechanism to explain hydraulic fracturing trends; they created a model to include this mechanism and it showed promising results; the paper from this research is ready for submission; they devised a way to identify and sort refractures in order to study their effects, and this paper is currently being written.

  10. FEEDBACK LINEARISATION APPLIED ON A HYDRAULIC

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik C.

    2005-01-01

    is on developing and applying several different feedback linearisation (FL) controllers to the individual servo actuators in a hydraulically driven servo robot to evaluate and compare their possiblities and limitations. This is done based on both simulation and experimental results.......Generally most hydraulic systems are intrensically non-linear, why applying linear control techniques typically results in conservatively dimensioned controllers to obtain stable performance. Non-linear control techniques have the potential of overcoming these problems, and in this paper the focus...

  11. Thermal hydraulics and mechanics core design programs

    International Nuclear Information System (INIS)

    Heinecke, J.

    1992-10-01

    The report documents the work performed within the Research and Development Task T hermal hydraulics and mechanics core design programs , funded by the German government. It contains the development of new codes, the extension of existing codes, the qualification and verification of codes and the development of a code library. The overall goal of this work was to adapt the system of thermal hydraulics and mechanics codes to the permanently growing requirements of the status of science and technology

  12. Database and prediction model for CANDU pressure tube diameter

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J.Y.; Park, J.H. [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2014-07-01

    The pressure tube (PT) diameter is basic data in evaluating the CCP (critical channel power) of a CANDU reactor. Since the CCP affects the operational margin directly, an accurate prediction of the PT diameter is important to assess the operational margin. However, the PT diameter increases by creep owing to the effects of irradiation by neutron flux, stress, and reactor operating temperatures during the plant service period. Thus, it has been necessary to collect the measured data of the PT diameter and establish a database (DB) and develop a prediction model of PT diameter. Accordingly, in this study, a DB for the measured PT diameter data was established and a neural network (NN) based diameter prediction model was developed. The established DB included not only the measured diameter data but also operating conditions such as the temperature, pressure, flux, and effective full power date. The currently developed NN based diameter prediction model considers only extrinsic variables such as the operating conditions, and will be enhanced to consider the effect of intrinsic variables such as the micro-structure of the PT material. (author)

  13. Electronic transport behavior of diameter-graded Ag nanowires

    International Nuclear Information System (INIS)

    Wang Xuewei; Yuan Zhihao

    2010-01-01

    Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

  14. Electronic transport behavior of diameter-graded Ag nanowires

    Science.gov (United States)

    Wang, Xue Wei; Yuan, Zhi Hao

    2010-05-01

    Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

  15. BWR 9 X 9 Fuel Assembly Thermal-Hydraulic Tests (2): Hydraulic Vibration Test

    International Nuclear Information System (INIS)

    Yoshiaki Tsukuda; Katsuichiro Kamimura; Toshiitsu Hattori; Akira Tanabe; Noboru Saito; Masahiko Warashina; Yuji Nishino

    2002-01-01

    Nuclear Power Engineering Corporation (NUPEC) conducted thermal-hydraulic projects for verification of thermal-hydraulic design reliability for BWR high-burnup 8 x 8 and 9 x 9 fuel assemblies, entrusted by the Ministry of Economy, Trade and Industry (METI). As a part of the NUPEC thermal-hydraulic projects, hydraulic vibration tests using full-scale test assemblies simulating 9 x 9 fuel assemblies were carried out to evaluate BWR fuel integrity. The test data were applied to development of a new correlation for the estimation of fuel rod vibration amplitude. (authors)

  16. Stochastic Modelling of the Hydraulic Anisotropy of Ash Impoundment Sediment

    Science.gov (United States)

    Slávik, Ivan

    2017-12-01

    In the case reported here the impoundments of a 400 MW coal heated power plant with an annual production of about 1.5 million tons of fuel ash are of the cross-valley type, operated by the simple and cheap „upstream method”. The aim of the research was to determine overall and local values of the permeability in horizontal as well as in vertical direction and the anisotropy of the thin-layered sedimented ash. The coal ashes are hydraulically transported through pipelines in form of a slurry and periodically floated on the beach of the impoundment. The ashes are deposited in the form of a thin-layered sediment, with random alternation of layers with a coarser or finer granularity. The ash impoundment sediment is anthropogenic sediment with horizontally laminated texture. Therefore, the sediment is anisotropic from the viewpoint of water seepage. The knowledge of the permeability and the seepage anisotropy of the sediment is a basic requirement for the design of an appropriate dewatering system. The seepage anisotropy of the ash sediment has been checked by means of stochastic modelling, based on the correlation between the effective grain diameter and the coefficient of permeability of the ash: the effective grain diameter and the thickness of individual layers have been proposed to be random events.

  17. Near-saturated surface soil hydraulic properties under different land uses in the St Denis National Wildlife Area, Saskatchewan, Canada

    Science.gov (United States)

    Bodhinayake, Waduwawatte; Si, Bing Cheng

    2004-10-01

    Surface soil hydraulic properties are key factors controlling the partition of rainfall and snowmelt into runoff and soil water storage, and their knowledge is needed for sound land management. The objective of this study was to evaluate the effects of three land uses (native grass, brome grass and cultivated) on surface soil hydraulic properties under near-saturated conditions at the St Denis National Wildlife Area, Saskatchewan, Canada. For each land use, water infiltration rates were measured using double-ring and tension infiltrometers at -0.3, -0.7, -1.5 and -2.2 kPa pressure heads. Macroporosity and unsaturated hydraulic properties of the surface soil were estimated. Mean field-saturated hydraulic conductivity (Kfs), unsaturated hydraulic conductivity at -0.3 kPa pressure head, inverse capillary length scale () and water-conducting macroporosity were compared for different land uses. These parameters of the native grass and brome grass sites were significantly (p 1.36 × 10-4 m in diameter in the three land uses. Land use modified near-saturated hydraulic properties of surface soil and consequently may alter the water balance of the area by changing the amount of surface runoff and soil water storage.

  18. Hydraulic Hybrid Fleet Vehicle Testing | Transportation Research | NREL

    Science.gov (United States)

    Hydraulic Hybrid Fleet Vehicle Evaluations Hydraulic Hybrid Fleet Vehicle Evaluations How Hydraulic Hybrid Vehicles Work Hydraulic hybrid systems can capture up to 70% of the kinetic energy that would -pressure reservoir to a high-pressure accumulator. When the vehicle accelerates, fluid in the high-pressure

  19. 46 CFR 112.50-3 - Hydraulic starting.

    Science.gov (United States)

    2010-10-01

    ... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be a... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping...

  20. A low order adaptive control scheme for hydraulic servo systems

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Bech, Michael Møller

    2015-01-01

    This paper deals with high-performance position control of hydraulics servo systems in general. The hydraulic servo system used is a two link robotic manipulator actuated by two hydraulic servo cylinders. A non-linear model of the hydraulic system and a Newton-Euler based model of the mechanical...

  1. Flow-driven simulation on variation diameter of counter rotating wind turbines rotor

    Directory of Open Access Journals (Sweden)

    Littik Y. Fredrika

    2018-01-01

    Full Text Available Wind turbines model in this paper developed from horizontal axis wind turbine propeller with single rotor (HAWT. This research aims to investigating the influence of front rotor diameter variation (D1 with rear rotor (D2 to the angular velocity optimal (ω and tip speed ratio (TSR on counter rotating wind turbines (CRWT. The method used transient 3D simulation with computational fluid dynamics (CFD to perform the aerodynamics characteristic of rotor wind turbines. The counter rotating wind turbines (CRWT is designed with front rotor diameter of 0.23 m and rear rotor diameter of 0.40 m. In this research, the wind velocity is 4.2 m/s and variation ratio between front rotor and rear rotor (D1/D2 are 0.65; 0.80; 1.20; 1.40; and 1.60 with axial distance (Z/D2 0.20 m. The result of this research indicated that the variation diameter on front rotor influence the aerodynamics performance of counter rotating wind turbines.

  2. Hydraulic fracture propagation modeling and data-based fracture identification

    Science.gov (United States)

    Zhou, Jing

    Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal drilling and hydraulic fracturing. Hydraulically induced fractures will most likely deviate from the bi-wing planar pattern and generate complex fracture networks due to mechanical interactions and reservoir heterogeneity, both of which render the conventional fracture simulators insufficient to characterize the fractured reservoir. Moreover, in reservoirs with ultra-low permeability, the natural fractures are widely distributed, which will result in hydraulic fractures branching and merging at the interface and consequently lead to the creation of more complex fracture networks. Thus, developing a reliable hydraulic fracturing simulator, including both mechanical interaction and fluid flow, is critical in maximizing hydrocarbon recovery and optimizing fracture/well design and completion strategy in multistage horizontal wells. A novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple nonplanar fractures' propagation in both homogeneous and heterogeneous reservoirs with or without pre-existing natural fractures. Initiation, growth, and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. This physics-based modeling approach leads to realistic fracture patterns without using the empirical rock failure and fracture propagation criteria required in conventional continuum methods. Based on this model, a sensitivity study is performed to investigate the effects of perforation spacing, in-situ stress anisotropy, rock properties (Young's modulus, Poisson's ratio, and compressive strength), fluid properties, and natural fracture properties on hydraulic fracture propagation. In addition, since reservoirs are buried thousands of feet below the surface, the

  3. Biofilm formation on a TiO2 nanotube with controlled pore diameter and surface wettability

    International Nuclear Information System (INIS)

    Anitha, V C; Narayan Banerjee, Arghya; Woo Joo, Sang; Lee, Jin-Hyung; Lee, Jintae; Ki Min, Bong

    2015-01-01

    Titania (TiO 2 ) nanotube arrays (TNAs) with different pore diameters (140 − 20 nm) are fabricated via anodization using hydrofluoric acid (HF) containing ethylene glycol (EG) by changing the HF-to-EG volume ratio and the anodization voltage. To evaluate the effects of different pore diameters of TiO 2 nanotubes on bacterial biofilm formation, Shewanella oneidensis (S. oneidensis) MR-1 cells and a crystal-violet biofilm assay are used. The surface roughness and wettability of the TNA surfaces as a function of pore diameter, measured via the contact angle and AFM techniques, are correlated with the controlled biofilm formation. Biofilm formation increases with the decreasing nanotube pore diameter, and a 20 nm TiO 2 nanotube shows the maximum biofilm formation. The measurements revealed that 20 nm surfaces have the least hydrophilicity with the highest surface roughness of ∼17 nm and that they show almost a 90% increase in the effective surface area relative to the 140 nm TNAs, which stimulate the cells more effectively to produce the pili to attach to the surface for more biofilm formation. The results demonstrate that bacterial cell adhesion (and hence, biofilm formation) can effectively be controlled by tuning the roughness and wettability of TNAs via controlling the pore diameters of TNA surfaces. This biofilm formation as a function of the surface properties of TNAs can be a potential candidate for both medical applications and as electrodes in microbial fuel cells. (paper)

  4. Tannins gravimetric yield condensed in Anadenanthera peregrina bark in different diameter classes

    Directory of Open Access Journals (Sweden)

    Caroline Junqueira Sartori

    2014-06-01

    Full Text Available This work aimed to determine the gravimetric yield of condensed tannins in the Anadenanthera peregrina bark in different diameter classes. Fifty-nine trees samples were collected of Anadenanthera peregrina, at 1.30m of the ground (diameter at breast height - DBH, distributed in seven diameter classes. The barks were dried and crushed in mill of hammer. Composite sample was made to prepare the extract. The extraction was done using water in the ratio 15:1 (v/w, added 3% sodium sulfite (w/w in water-bath at 70°C for 4 hours. The material was filtered using fine cloth strainer and concentrated on a heating plate at approximately 150 g. It was determined the extract mass and removed 10 g for obtaining solids content and 20g for the Stiasny's index. The average values of total solids content, Stiasny's index, condensed tannin content and the compound content non-tannin were 11.34%; 75.79%; 12.76% and 4.07%, respectively. The content of solids, Stiasny's index, compound content non-tannin show significant differences between diameter classes. For the condensed tannins production, the diameter class parameter there was no influence.

  5. Envera Variable Compression Ratio Engine

    Energy Technology Data Exchange (ETDEWEB)

    Charles Mendler

    2011-03-15

    the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new

  6. Proceedings of the 1991 national conference on hydraulic engineering

    International Nuclear Information System (INIS)

    Shane, R.M.

    1991-01-01

    This book contains the proceedings of the 1991 National Conference of Hydraulic Engineering. The conference was held in conjunction with the International Symposium on Ground Water and a Software Exchange that facilitated exchange of information on recent software developments of interest to hydraulic engineers. Also included in the program were three mini-symposia on the Exclusive Economic Zone, Data Acquisition, and Appropriate Technology. Topics include sedimentation; appropriate technology; exclusive economic zone hydraulics; hydraulic data acquisition and display; innovative hydraulic structures and water quality applications of hydraulic research, including the hydraulics of aerating turbines; wetlands; hydraulic and hydrologic extremes; highway drainage; overtopping protection of dams; spillway design; coastal and estuarine hydraulics; scale models; computation hydraulics; GIS and expert system applications; watershed response to rainfall; probabilistic approaches; and flood control investigations

  7. Electro-Pneumatic Control System with Hydraulically Positioning Actuator Motor

    Directory of Open Access Journals (Sweden)

    V. N. Pilgunov

    2016-01-01

    factors, which determine operation conditions of the pneumatic cylinder, have the impact on it. Experimental investigation of piston landing was conducted using the pneumatic cylinder with piston and rod diameters of 32 and 16 mm, respectively, at operating pressure of 0.8 MPa. With a vertical arrangement of the pneumatic cylinder axis, the control weights of a dead-weight pressure-gauge tester created a constant component of the load and its variation, and an indicator with resolution of 0.05 mm estimated a landing value. The article shows the calculated data of piston landing, which are in good compliance with the experimental results.To substantially reduce the piston landing for the holding period of the load varying in value and sign was designed a hydraulic positioner of pneumatic cylinder piston, and its operation quality is studied on the physical layout of electro-pneumatic control system operating in the discrete and tracking modes.For control system service, work programs of the programmable logic controller integrated in the control circuit of the hydraulic positioner in discrete mode, and, as a digital discriminator, in tracking mode are developed. In conclusion as a result of the research activities the article estimates the impact of factors on the quality of the load position at the time of its hold and notes a high efficiency of the hydraulic positioner of pneumatic cylinder piston both in discrete mode and in tracking one.

  8. CHF predictor derived from a 3D thermal-hydraulic code and an advanced statistical method

    International Nuclear Information System (INIS)

    Banner, D.; Aubry, S.

    2004-01-01

    A rod bundle CHF predictor has been determined by using a 3D code (THYC) to compute local thermal-hydraulic conditions at the boiling crisis location. These local parameters have been correlated to the critical heat flux by using an advanced statistical method based on spline functions. The main characteristics of the predictor are presented in conjunction with a detailed analysis of predictions (P/M ratio) in order to prove that the usual safety methodology can be applied with such a predictor. A thermal-hydraulic design criterion is obtained (1.13) and the predictor is compared with the WRB-1 correlation. (author)

  9. Numerical study of two side-by-side cylinders with unequal diameters at low Reynolds number

    International Nuclear Information System (INIS)

    Gao, Y Y; Wang, X K; Tan, S K

    2012-01-01

    Two-dimensional laminar flow about two side-by-side unequal cylinders with different diameter ratios d/D and centre-to-centre spacing ratios T/D at Re=300 (based on the larger cylinder diameter) was simulated using a CFD software. Comparisons of experimental and numerical results were made to elucidate the degree of interference due to d/D and T/D and their effects on the flow patterns and vortex shedding frequencies. The findings showed that the flow patterns behind two unequal cylinders were distinctly different from that behind two equal side-by-side cylinders, with distinct in-phase and anti-phase vortex shedding, and random switching of modes of vortex shedding.

  10. Synthesis of subnanometer-diameter vertically aligned single-walled carbon nanotubes with copper-anchored cobalt catalysts

    Science.gov (United States)

    Cui, Kehang; Kumamoto, Akihito; Xiang, Rong; An, Hua; Wang, Benjamin; Inoue, Taiki; Chiashi, Shohei; Ikuhara, Yuichi; Maruyama, Shigeo

    2016-01-01

    We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high-quality SWNTs are expected to pave the way to replace silicon for next-generation optoelectronic and photovoltaic devices.We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high

  11. Numerical flow analyses of a two-phase hydraulic coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hur, N.; Kwak, M.; Moshfeghi, M. [Sogang University, Seoul (Korea, Republic of); Chang, C.-S.; Kang, N.-W. [VS Engineering, Seoul (Korea, Republic of)

    2017-05-15

    We investigated flow characteristics in a hydraulic coupling at different charged water conditions and speed ratios. Hence, simulations were performed for three-dimensional two-phase flow by using the VOF method. The realizable k-ε turbulence model was adopted. To resolve the interaction of passing blades of the primary and secondary wheels, simulations were conducted in the unsteady framework using a sliding grid technique. The results show that the water-air distribution inside the wheel is strongly dependent upon both amount of charged water and speed ratio. Generally, air is accumulated in the center of the wheel, forming a toroidal shape wrapped by the circulating water. The results also show that at high speed ratios, the solid-body-like rotation causes dry areas on the periphery of the wheels and, hence, considerably decreases the circulating flow rate and the transmitted torque. Furthermore, the momentum transfer was investigated through the concept of a mass flux triangle based on the local velocity multiplied by the local mixture density instead of the velocity triangle commonly used in a single-phase turbomachine analysis. Also, the mass fluxes along the radius of the coupling in the partially charged and fully charged cases were found to be completely different. It is shown that the flow rate at the interfacial plane and also the transmitted torque are closely related and are strongly dependent upon both the amount of charged water and speed ratio. Finally, a conceptual categorization together with two comprehensive maps was provided for the torque transmission and also circulating flow rates. These two maps in turn exhibit valuable engineering information and can serve as bases for an optimal design of a hydraulic coupling.

  12. Isotachophoresis system having larger-diameter channels flowing into channels with reduced diameter and with selectable counter-flow

    Energy Technology Data Exchange (ETDEWEB)

    Mariella, Jr., Raymond P.

    2018-03-06

    An isotachophoresis system for separating a sample containing particles into discrete packets including a flow channel, the flow channel having a large diameter section and a small diameter section; a negative electrode operably connected to the flow channel; a positive electrode operably connected to the flow channel; a leading carrier fluid in the flow channel; a trailing carrier fluid in the flow channel; and a control for separating the particles in the sample into discrete packets using the leading carrier fluid, the trailing carrier fluid, the large diameter section, and the small diameter section.

  13. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  14. Influence of high intensity ultrasound with different probe diameter ...

    African Journals Online (AJOL)

    The main goal of this research is to analyze the influence of ultrasonic probe diameters (7 and 10 mm) of high-intensity ultrasound with constant frequency (30 kHz) on the degree of homogenization (variance) of cow milk. Influence of different probe diameters on the physical properties of cow milk was also tested. Changes ...

  15. Lumbar Vertebral Canal Diameters in Adult Ugandan Skeletons ...

    African Journals Online (AJOL)

    Background: Normal values of lumbar vertebral canal diameters are useful in facilitating diagnosis of lumbar vertebral canal stenosis. Various studies have established variation on values between different populations, gender, age, and ethnic groups. Objectives: To determine the lumbar vertebral canal diameters in adult ...

  16. Relationships between diameter and height of trees in natural ...

    African Journals Online (AJOL)

    Relationships between diameter and height of trees in natural tropical forest in Tanzania. Wilson A Mugasha, Ole M Bollandsås, Tron Eid. Abstract. The relationship between tree height (h) and tree diameter at breast height (dbh) is an important element describing forest stands. In addition, h often is a required variable in ...

  17. Heritability of optic disc diameters: a twin study

    DEFF Research Database (Denmark)

    Drobnjak, Dragana; Taarnhøj, Nina Charlotte; Mitchell, Paul

    2011-01-01

    , additive genetic factors (i.e. heritability) explained 77% (95% CI: 65-85%) of variation of vertical disc diameters, whereas estimated unshared environmental effect was 23% (95% CI: 15-35%). For vertical cup diameters, heritability accounted for 70% (95% CI: 55-80%) and environmental factors 30% (95% CI...

  18. Generalized height-diameter models for Populus tremula L. stands

    African Journals Online (AJOL)

    USER

    2010-07-12

    Jul 12, 2010 ... and stand density) into the base height-diameter models increased the accuracy of prediction for P. tremula. .... parameter estimates compared with those obtained with ... using coefficient of determination for non-linear regression (. 2. R ), ..... stochastic height-diameter model for maritime pine ecoregions in.

  19. The study of crosslinked fluid leakoff in hydraulic fracturing physical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Grothe, Vinicius Perrud; Ribeiro, Paulo Roberto [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Petroleo; Sousa, Jose Luiz Antunes de Oliveira e [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia. Dept. de Estruturas; Fernandes, Paulo Dore [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2000-07-01

    The fluid loss plays an important role in the design and execution of hydraulic fracturing treatments. The main objectives of this work were: the study of the fluid loss associated with the propagation of hydraulic fractures generated at laboratory; and the comparison of two distinct methods for estimating leakoff coefficients - Nolte analysis and the filtrate volume vs. square root of time plot. Synthetic rock samples were used as well as crosslinked hydroxypropyl guar (HPG) fluids in different polymer concentrations. The physical simulations comprised the confinement of (0.1 x 0.1 x 0.1) m{sup 3} rock samples in a load cell for the application of an in situ stress field. Different flow rates were employed in order to investigate shear effects on the overall leakoff coefficient. Horizontal radial fractures were hydraulically induced with approximate diameters, what was accomplished by controlling the injection time. Leakoff coefficients determined by means of the pressure decline analysis were compared to coefficients obtained from static filtration tests, considering similar experimental conditions. The research results indicated that the physical simulation of hydraulic fracturing may be regarded as an useful tool for evaluating the effectiveness of fracturing fluids and that it can supply reliable estimates of fluid loss coefficients. (author)

  20. Seismic characteristics of tensile fracture growth induced by hydraulic fracturing

    Science.gov (United States)

    Eaton, D. W. S.; Van der Baan, M.; Boroumand, N.

    2014-12-01

    Hydraulic fracturing is a process of injecting high-pressure slurry into a rockmass to enhance its permeability. Variants of this process are used for unconventional oil and gas development, engineered geothermal systems and block-cave mining; similar processes occur within volcanic systems. Opening of hydraulic fractures is well documented by mineback trials and tiltmeter monitoring and is a physical requirement to accommodate the volume of injected fluid. Numerous microseismic monitoring investigations acquired in the audio-frequency band are interpreted to show a prevalence of shear-dominated failure mechanisms surrounding the tensile fracture. Moreover, the radiated seismic energy in the audio-frequency band appears to be a miniscule fraction (<< 1%) of the net injected energy, i.e., the integral of the product of fluid pressure and injection rate. We use a simple penny-shaped crack model as a predictive framework to describe seismic characteristics of tensile opening during hydraulic fracturing. This model provides a useful scaling relation that links seismic moment to effective fluid pressure within the crack. Based on downhole recordings corrected for attenuation, a significant fraction of observed microseismic events are characterized by S/P amplitude ratio < 5. Despite the relatively small aperture of the monitoring arrays, which precludes both full moment-tensor analysis and definitive identification of nodal planes or axes, this ratio provides a strong indication that observed microseismic source mechanisms have a component of tensile failure. In addition, we find some instances of periodic spectral notches that can be explained by an opening/closing failure mechanism, in which fracture propagation outpaces fluid velocity within the crack. Finally, aseismic growth of tensile fractures may be indicative of a scenario in which injected energy is consumed to create new fracture surfaces. Taken together, our observations and modeling provide evidence that

  1. Lysosome Transport as a Function of Lysosome Diameter

    Science.gov (United States)

    Bandyopadhyay, Debjyoti; Cyphersmith, Austin; Zapata, Jairo A.; Kim, Y. Joseph; Payne, Christine K.

    2014-01-01

    Lysosomes are membrane-bound organelles responsible for the transport and degradation of intracellular and extracellular cargo. The intracellular motion of lysosomes is both diffusive and active, mediated by motor proteins moving lysosomes along microtubules. We sought to determine how lysosome diameter influences lysosome transport. We used osmotic swelling to double the diameter of lysosomes, creating a population of enlarged lysosomes. This allowed us to directly examine the intracellular transport of the same organelle as a function of diameter. Lysosome transport was measured using live cell fluorescence microscopy and single particle tracking. We find, as expected, the diffusive component of intracellular transport is decreased proportional to the increased lysosome diameter. Active transport of the enlarged lysosomes is not affected by the increased lysosome diameter. PMID:24497985

  2. Study on an Axial Flow Hydraulic Turbine with Collection Device

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2014-01-01

    Full Text Available We propose a new type of portable hydraulic turbine that uses the kinetic energy of flow in open channels. The turbine comprises a runner with an appended collection device that includes a diffuser section in an attempt to improve the output by catching and accelerating the flow. With such turbines, the performance of the collection device, and a composite body comprising the runner and collection device were studied using numerical analysis. Among four stand-alone collection devices, the inlet velocity ratio was most improved by the collection device featuring an inlet nozzle and brim. The inlet velocity ratio of the composite body was significantly lower than that of the stand-alone collection device, owing to the resistance of the runner itself, the decreased diffuser pressure recovery coefficient, and the increased backpressure coefficient. However, at the maximum output tip speed ratio, the inlet velocity ratio and the loading coefficient were approximately 31% and 22% higher, respectively, for the composite body than for the isolated runner. In particular, the input power coefficient significantly increased (by approximately 2.76 times owing to the increase in the inlet velocity ratio. Verification tests were also conducted in a real canal to establish the actual effectiveness of the turbine.

  3. Hydraulic Yaw System for Wind Turbines with New Compact Hydraulic Motor Principle

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Mørk; Hansen, Michael Rygaard; Mouritsen, Ole Ø.

    2011-01-01

    This paper presents a new hydraulic yaw system for wind turbines. The basic component is a new type of hydraulic motor characterized by an extraordinary high specific displacement yielding high output torque in a compact form. The focus in the paper is the volumetric efficiency of the motor, which...

  4. Comparative study of methods to estimate hydraulic parameters in the hydraulically undisturbed Opalinus Clay (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.; Matray, J.-M. [Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, (France); Yu, C.; Gonçalvès, J. [Aix Marseille Université UMR 6635 CEREGE Technopôle Environnement Arbois-Méditerranée Aix-en-Provence, Cedex 4 (France); and others

    2017-04-15

    The deep borehole (DB) experiment gave the opportunity to acquire hydraulic parameters in a hydraulically undisturbed zone of the Opalinus Clay at the Mont Terri rock laboratory (Switzerland). Three methods were used to estimate hydraulic conductivity and specific storage values of the Opalinus Clay formation and its bounding formations through the 248 m deep borehole BDB-1: application of a Poiseuille-type law involving petrophysical measurements, spectral analysis of pressure time series and in situ hydraulic tests. The hydraulic conductivity range in the Opalinus Clay given by the first method is 2 × 10{sup -14}-6 × 10{sup -13} m s{sup -1} for a cementation factor ranging between 2 and 3. These results show low vertical variability whereas in situ hydraulic tests suggest higher values up to 7 × 10{sup -12} m s{sup -1}. Core analysis provides economical estimates of the homogeneous matrix hydraulic properties but do not account for heterogeneities at larger scale such as potential tectonic conductive features. Specific storage values obtained by spectral analysis are consistent and in the order of 10{sup -6} m{sup -1}, while formulations using phase shift and gain between pore pressure signals were found to be inappropriate to evaluate hydraulic conductivity in the Opalinus Clay. The values obtained are globally in good agreement with the ones obtained previously at the rock laboratory. (authors)

  5. Power Management in Mobile Hydraulic Applications - An Approach for Designing Hydraulic Power Supply Systems

    DEFF Research Database (Denmark)

    Pedersen, Henrik Clemmensen

    2004-01-01

    Throughout the last three decades energy consumption has become one of the primary design aspects in hydraulic systems, especially for mobile hydraulic systems, as power and cooling capacity here is at limited disposal. Considering the energy usage, this is dependent on component efficiency, but ...... the hydraulic power supply in the most energy efficient way, when considering a number of load situations. Finally an example of the approach is shown to prove its validity.}......Throughout the last three decades energy consumption has become one of the primary design aspects in hydraulic systems, especially for mobile hydraulic systems, as power and cooling capacity here is at limited disposal. Considering the energy usage, this is dependent on component efficiency...

  6. A study on the effective hydraulic conductivity of an anisotropic porous medium

    International Nuclear Information System (INIS)

    Seong, Kwan Jae

    2002-01-01

    Effective hydraulic conductivity of a statistically anisotropic heterogeneous medium is obtained for steady two-dimensional flows employing stochastic analysis. Flow equations are solved up to second order and the effective conductivity is obtained in a semi-analytic form depending only on the spatial correlation function and the anisotropy ratio of the hydraulic conductivity field, hence becoming a true intrinsic property independent of the flow field. Results are obtained using a statistically anisotropic Gaussian correlation function where the anisotropic is defined as the ratio of integral scales normal and parallel to the mean flow direction. Second order results indicate that the effective conductivity of an anisotropic medium is greater than that of an isotropic one when the anisotropy ratio is less than one and vice versa. It is also found that the effective conductivity has upper and lower bounds of the arithmetic and the harmonic mean conductivities

  7. The hydraulic capacity of deteriorating sewer systems.

    Science.gov (United States)

    Pollert, J; Ugarelli, R; Saegrov, S; Schilling, W; Di Federico, V

    2005-01-01

    Sewer and wastewater systems suffer from insufficient capacity, construction flaws and pipe deterioration. Consequences are structural failures, local floods, surface erosion and pollution of receiving waters bodies. European cities spend in the order of five billion Euro per year for wastewater network rehabilitation. This amount is estimated to increase due to network ageing. The project CARE-S (Computer Aided RE-habilitation of Sewer Networks) deals with sewer and storm water networks. The final project goal is to develop integrated software, which provides the most cost-efficient system of maintenance, repair and rehabilitation of sewer networks. Decisions on investments in rehabilitation often have to be made with uncertain information about the structural condition and the hydraulic performance of a sewer system. Because of this, decision-making involves considerable risks. This paper presents the results of research focused on the study of hydraulic effects caused by failures due to temporal decline of sewer systems. Hydraulic simulations are usually carried out by running commercial models that apply, as input, default values of parameters that strongly influence results. Using CCTV inspections information as dataset to catalogue principal types of failures affecting pipes, a 3D model was used to evaluate their hydraulic consequences. The translation of failures effects in parameters values producing the same hydraulic conditions caused by failures was carried out through the comparison of laboratory experiences and 3D simulations results. Those parameters could be the input of 1D commercial models instead of the default values commonly inserted.

  8. Vibration Isolation for Parallel Hydraulic Hybrid Vehicles

    Directory of Open Access Journals (Sweden)

    The M. Nguyen

    2008-01-01

    Full Text Available In recent decades, several types of hybrid vehicles have been developed in order to improve the fuel economy and to reduce the pollution. Hybrid electric vehicles (HEV have shown a significant improvement in fuel efficiency for small and medium-sized passenger vehicles and SUVs. HEV has several limitations when applied to heavy vehicles; one is that larger vehicles demand more power, which requires significantly larger battery capacities. As an alternative solution, hydraulic hybrid technology has been found effective for heavy duty vehicle because of its high power density. The mechanical batteries used in hydraulic hybrid vehicles (HHV can be charged and discharged remarkably faster than chemical batteries. This feature is essential for heavy vehicle hybridization. One of the main problems that should be solved for the successful commercialization of HHV is the excessive noise and vibration involving with the hydraulic systems. This study focuses on using magnetorheological (MR technology to reduce the noise and vibration transmissibility from the hydraulic system to the vehicle body. In order to study the noise and vibration of HHV, a hydraulic hybrid subsystem in parallel design is analyzed. This research shows that the MR elements play an important role in reducing the transmitted noise and vibration to the vehicle body. Additionally, locations and orientations of the isolation system also affect the efficiency of the noise and vibration mitigation. In simulations, a skyhook control algorithm is used to achieve the highest possible effectiveness of the MR isolation system.

  9. Effects of Diameter on Initial Stiffness of P-Y Curves for Large-Diameter Piles in Sand

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Augustesen, Anders Hust

    2010-01-01

    is developed for slender piles with diameters up to approximately 2.0 m. Hence, the method is not validated for piles with diameters of 4–6 m. The aim of the paper is to extend the p-y curve method to large-diameter non-slender piles in sand by considering the effects of the pile diameter on the soil-pile...... interaction. Hence, a modified expression for the p-y curves for statically loaded piles in sand is proposed in which the initial slope of the p-y curves depends on the depth below the soil surface, the pile diameter and the internal angle of friction. The evaluation is based on three-dimensional numerical...... analyses by means of the commercial program FLAC3D incorporating a Mohr-Coulomb failure criterion. The numerical model is validated with laboratory tests in a pressure tank at Aalborg University....

  10. Displacement characteristics of a piezoactuator-based prototype microactuator with a hydraulic displacement amplification system

    International Nuclear Information System (INIS)

    Muralidhara; Rao, Rathnamala

    2015-01-01

    In this study, a new piezoactuator-based prototype microactuator is proposed with a hydraulic displacement amplification system. A piezoactuator is used to deflect a diaphragm which displaces a certain volume of hydraulic fluid into a smaller-diameter piston chamber, thereby amplifying the displacement at the other end of the piston. An electro-mechanical model is implemented to estimate the displacement of a multilayer piezoelectric actuator for the applied input voltage considering the hysteresis behavior. The displacement characteristics of the proposed microactuator are studied for triangular actuation voltage signal. Results of the experiments and simulation of the displacement behavior of the stacked piezoactuator and the amplified displacement of the prototype actuator were compared. Experimental results suggest that the mathematical model developed for the new piezoactuator-based prototype actuator is capable of estimating its displacement behavior accurately, within an error of 1.2%.

  11. The reduction of noise from hydraulic equipments; La reduction du bruit provenant des equipements hydrauliques

    Energy Technology Data Exchange (ETDEWEB)

    Gential, R.

    1996-09-01

    Noise pollution from hydraulic equipments (bath filling, toilets taps, waste waters flow, vibrations, knocks in water pipes, dilatation clattering in heating pipes, hissing of heater taps etc..) are one of the principal causes of nuisance inside residential buildings. Solutions exist and consist in the replacement of old cocks and fittings, the use of soundproof clamps for pipes and noise absorbing supports for baths etc.. This paper summarizes the available modern equipments with a low-noise warranty (cocks and fittings, noise dampers, anti-backflow valves, pressure reducers) and the practical solutions for the modification of existing installations (increase of pipe diameters, reduction of pipe lengths, use of flexible fittings, hydraulic counterbalancing of water flows in heaters etc..). (J.S.)

  12. Displacement characteristics of a piezoactuator-based prototype microactuator with a hydraulic displacement amplification system

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhara [NMAMIT, Nitte (India); Rao, Rathnamala [NITK, Surathkal (India)

    2015-11-15

    In this study, a new piezoactuator-based prototype microactuator is proposed with a hydraulic displacement amplification system. A piezoactuator is used to deflect a diaphragm which displaces a certain volume of hydraulic fluid into a smaller-diameter piston chamber, thereby amplifying the displacement at the other end of the piston. An electro-mechanical model is implemented to estimate the displacement of a multilayer piezoelectric actuator for the applied input voltage considering the hysteresis behavior. The displacement characteristics of the proposed microactuator are studied for triangular actuation voltage signal. Results of the experiments and simulation of the displacement behavior of the stacked piezoactuator and the amplified displacement of the prototype actuator were compared. Experimental results suggest that the mathematical model developed for the new piezoactuator-based prototype actuator is capable of estimating its displacement behavior accurately, within an error of 1.2%.

  13. Test procedure for the Master-Lee and the modified Champion four inch hydraulic cutters

    International Nuclear Information System (INIS)

    Crystal, J.B.

    1995-01-01

    The Master-Lee and the modified Champion 4 Inch hydraulic cutters are being retested to gather and document information related to the following: determine if the Master-Lee cutters will cut the trunnions of an Aluminum fuel canister and a Stainless Steel fuel canister; determine if the Master-Lee cutters will cut 1 1/2 inch diameter fire hose; determine if the modified Champion 4 inch blade will cut sections of piping; and determine the effectiveness of the centering device for the Champion 4 Inch cutters. Determining the limitations of the hydraulic cutter will aid in the process of debris removal in the K-Basin. Based on a previous test, the cutters were returned to the manufacturer for modifications. The modifications to the Champion 4 Inch Cutter and further testing of the Master-Lee Cutter are the subjects of these feature tests

  14. Numerical calculation for flow field of servo-tube guided hydraulic control rod driving system

    International Nuclear Information System (INIS)

    He Keyu; Han Weishi

    2010-01-01

    A new-style hydraulic control rod driving mechanism was put forward by using servo-tube control elements for the design of control rod driving mechanism. The results of numerical simulation by CFD program Fluent for flow field of hydraulic driving cylinder indicate that the bigger the outer diameter of servo-tube, the smaller the resistance coefficient of variable throttle orifice. The zero position gap of variable throttle orifice could be determined on 0.2 mm in the design. The pressure difference between the upper and nether surfaces of piston was mainly created by the throttle function of fixed throttle orifice. It can be effectively controlled by changing the gap of variable throttle orifice. And the lift force of driving cylinder is able to meet the requirement on the design load. (authors)

  15. Effect of the microstructure of mortars with low hydraulicity slag on their behavior in aggressive environments

    Directory of Open Access Journals (Sweden)

    Ahmed Hadj sadok

    2018-01-01

    Full Text Available Slag is one of the most used cement additives. Due to its latent hydraulic nature, attached to its hydraulicity, it can contribute to a microstructural modification and an improvement of the durability of the concrete face of aggressive environments. In this study, a low active slag is used in the manufacture of mortars as a substitute for cement, at a maximum rate of 50%. Firstly, a study of the microstructure with mercury porosimetry was used for determination of microstructural parameters (porosity, diameters and volume distribution. The behavior of mortars in aggressive environments (sodium and magnesium sulphate and seawater was studied later. Despite the low reactivity of studied slag, its presence especially at 50% rate, in the long term, has led to a refinement of the microstructure. This effect, among others, led to better resistivity of the mortars in the sulphate environnements.

  16. Observations of a potential size-effect in experimental determination of the hydraulic properties of fractures

    International Nuclear Information System (INIS)

    Witherspoon, P.A.; Amick, C.H.; Gale, J.E.; Iwai, K.

    1979-05-01

    In several recent investigations, experimental studies on the effect of normal stress on the hydraulic conductivity of a single fracture were made on three rock specimens ranging in cross-sectional area from 0.02 m 2 to over 1.0 m 2 . At the maximum stress levels that could be attained (10 to 20 MPa), minimum values of the fracture hydraulic conductivity were not the same for each rock specimen. These minimum values increased with specimen size, indicating that the determination of fracture conductivity may be significantly influenced by a size effect. The implications of these results are important. Cores collected in the field are normally not larger than 0.15 m in diameter. However, the results of this work suggest that when this size core is used for laboratory investigations, the results may be nonconservative in that fracture permeabilities will be significantly lower than will be found in the field. 6 figures

  17. Micro-hydromechanical deep drawing of metal cups with hydraulic pressure effects

    Science.gov (United States)

    Luo, Liang; Jiang, Zhengyi; Wei, Dongbin; Wang, Xiaogang; Zhou, Cunlong; Huang, Qingxue

    2018-03-01

    Micro-metal products have recently enjoyed high demand. In addition, metal microforming has drawn increasing attention due to its net-forming capability, batch manufacturing potential, high product quality, and relatively low equipment cost. Micro-hydromechanical deep drawing (MHDD), a typical microforming method, has been developed to take advantage of hydraulic force. With reduced dimensions, the hydraulic pressure development changes; accordingly, the lubrication condition changes from the macroscale to the microscale. A Voronoi-based finite element model is proposed in this paper to consider the change in lubrication in MHDD according to open and closed lubricant pocket theory. Simulation results agree with experimental results concerning drawing force. Changes in friction significantly affect the drawing process and the drawn cups. Moreover, defined wrinkle indexes have been shown to have a complex relationship with hydraulic pressure. High hydraulic pressure can increase the maximum drawing ratio (drawn cup height), whereas the surface finish represented by the wear is not linearly dependent on the hydraulic pressure due to the wrinkles.

  18. Monitoring Hydraulic Fracturing Using Ground-Based Controlled Source Electromagnetics

    Science.gov (United States)

    Hickey, M. S.; Trevino, S., III; Everett, M. E.

    2017-12-01

    Hydraulic fracturing allows hydrocarbon production in low permeability formations. Imaging the distribution of fluid used to create a hydraulic fracture can aid in the characterization of fracture properties such as extent of plume penetration as well as fracture azimuth and symmetry. This could contribute to improving the efficiency of an operation, for example, in helping to determine ideal well spacing or the need to refracture a zone. A ground-based controlled-source electromagnetics (CSEM) technique is ideal for imaging the fluid due to the change in field caused by the difference in the conductive properties of the fluid when compared to the background. With advances in high signal to noise recording equipment, coupled with a high-power, broadband transmitter we can show hydraulic fracture extent and azimuth with minimal processing. A 3D finite element code is used to model the complete well casing along with the layered subsurface. This forward model is used to optimize the survey design and isolate the band of frequencies with the best response. In the field, the results of the modeling are also used to create a custom pseudorandom numeric (PRN) code to control the frequencies transmitted through a grounded dipole source. The receivers record the surface voltage across two grounded dipoles, one parallel and one perpendicular to the transmitter. The data are presented as the displays of amplitude ratios across several frequencies with the associated spatial information. In this presentation, we show multiple field results in multiple basins in the United States along with the CSEM theory used to create the survey designs.

  19. The Relationship amongst Intervertebral Disc Vertical Diameter, Lateral Foramen Diameter and Nerve Root Impingement in Lumbar Vertebra

    Directory of Open Access Journals (Sweden)

    Yusof MI

    2018-03-01

    Full Text Available Introduction: The vertical diameter of the foramen is dependent upon the vertical diameter of the corresponding intervertebral disc. A decrease in disc vertical diameter has direct anatomic consequences to the foraminal diameter and area available for the nerve root passing through it. This study is to establish the relationship amongst the intervertebral disc vertical diameter, lateral foramen diameters and nerve root compression in the lumbar vertebra. Materials and Methods: Measurements of the study parameters were performed using sagittal MRI images. The parameters studied were: intervertebral disc vertical diameter (DVD, foraminal vertical diameter (FVD, foraminal transverse diameter (FTD and nerve root diameter (NRD of both sides. The relationship between the measured parameters were then analyzed. Results: A total of 62 MRI images were available for this study. Statistical analysis showed moderate to strong correlation between DVD and FVD at all the lumbar levels except at left L23 and L5S1 and right L3L4 and L4L5. Correlation between DVD and FTD were not significant at all lumbar levels. Regression analysis showed that a decrease of 1mm of DVD was associated with 1.3, 1.7, 3.3, 3.3 and 1.3mm reduction of FVD at L1L2, L2L3, L3L4, L4L5 and L5S1 respectively. Conclusion: Reduction of DVD was associated with reduction of FVD. However, FVD was relatively wide for the nerve root even with complete loss of DVD. FTD was much narrower than the FVD making it more likely to cause nerve root compression at the exit foramina. These anatomical details should be given consideration in treating patients with lateral canal stenosis.

  20. Brain Arterial Diameters as a Risk Factor for Vascular Events.

    Science.gov (United States)

    Gutierrez, Jose; Cheung, Ken; Bagci, Ahmet; Rundek, Tatjana; Alperin, Noam; Sacco, Ralph L; Wright, Clinton B; Elkind, Mitchell S V

    2015-08-06

    Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events. Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, called the brain arterial remodeling (BAR) score, was obtained by averaging the measured diameters within each individual. Individuals with a BAR score -2 and 2 SDs had the largest diameters. All vascular events were recorded prospectively after the brain magnetic resonance imaging. Spline curves and incidence rates were used to test our hypothesis. The association of the BAR score with death (P=0.001), vascular death (P=0.02), any vascular event (P=0.05), and myocardial infarction (P=0.10) was U-shaped except for ischemic stroke (P=0.74). Consequently, incidence rates for death, vascular death, myocardial infarction, and any vascular event were higher in individuals with the largest diameters, whereas individuals with the smallest diameters had a higher incidence of death, vascular death, any vascular event, and ischemic stroke compared with individuals with average diameters. The risk of death, vascular death, and any vascular event increased at both extremes of brain arterial diameters. The pathophysiology linking brain arterial remodeling to systemic vascular events needs further research. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  1. HOW TO STEER THE TRANSMISSION RATIO OF PLANETARY CONTINUOUSLY ADJUSTABLE GEAR TRAIN

    Directory of Open Access Journals (Sweden)

    A. M. Dankov

    2016-01-01

    Full Text Available The known attempts to create a continuously-adjustable gear train with solid gears have led to development of some so-called adaptive gears. The most structurally simple version of continuously- adjustable gear train is a two-wheel planetary gear. It is an obvious fact that an active regulation of gear ratio for the gear should be based on the presence of con- trolled elements (parameters and a mechanism for their control. In respect of the mentioned gear one of the controlled elements that is a compound central toothed gear has such controlled parameter as a nominal pitch diameter. In this case it can rotate or remain motionless. Other controlled element which is a planetary carrier has its own radius as a controlled parameter and makes a rotary motion with a great speed of a leading element. The purpose of the control mechanism is to ensure radial displacement of central toothed gear and planet gear sectors in the working gear. The paper describes the mechanism modifications and considers two variants for transfer of control action from its source to an object to be controlled. The transfer is ensured by mechanical gears (two variants and hydraulics.

  2. Diameter dependent failure current density of gold nanowires

    International Nuclear Information System (INIS)

    Karim, S; Maaz, K; Ali, G; Ensinger, W

    2009-01-01

    Failure current density of single gold nanowires is investigated in this paper. Single wires with diameters ranging from 80 to 720 nm and length 30 μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density was investigated while keeping the wires embedded in the polymer matrix and ramping up the current until failure occurred. The current density is found to increase with diminishing diameter and the wires with a diameter of 80 nm withstand 1.2 x 10 12 A m -2 before undergoing failure. Possible reasons for these results are discussed in this paper.

  3. Reduced arterial diameter during static exercise in humans

    DEFF Research Database (Denmark)

    Olesen, H L; Mitchell, J H; Friedman, D B

    1995-01-01

    In eight subjects luminal diameter of the resting limb radial and dorsalis pedis arteries was determined by high-resolution ultrasound (20 MHz). This measurement was followed during rest and during 2 min of static handgrip or of one-leg knee extension at 30% of maximal voluntary contraction...... exertion was approximately 15 units after both types of exercise. The dorsalis pedis arterial diameter was 1.50 +/- 0.20 mm (mean and SE) and the radial AD 2.45 +/- 0.12 mm. During both types of contractions the luminal diameters decreased approximately 3.5% within the first 30 s (P

  4. Laser direct writing using submicron-diameter fibers.

    Science.gov (United States)

    Tian, Feng; Yang, Guoguang; Bai, Jian; Xu, Jianfeng; Hou, Changlun; Liang, Yiyong; Wang, Kaiwei

    2009-10-26

    In this paper, a novel direct writing technique using submicron-diameter fibers is presented. The submicron-diameter fiber probe serves as a tightly confined point source and it adopts micro touch mode in the process of writing. The energy distribution of direct writing model is analyzed by Three-Dimension Finite-Difference Time-Domain method. Experiments demonstrate that submicron-diameter fiber direct writing has some advantages: simple process, 350-nm-resolution (lower than 442-nm-wavelength), large writing area, and controllable width of lines. In addition, by altering writing direction of lines, complex submicron patterns can be fabricated.

  5. A Computational Model of Hydraulic Volume Displacement Drive

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2014-01-01

    Full Text Available The paper offers a computational model of industrial-purpose hydraulic drive with two hydraulic volume adjustable working chamber machines (pump and motor. Adjustable pump equipped with the pressure control unit can be run together with several adjustable hydraulic motors on the principle of three-phase hydraulic socket-outlet with high-pressure lines, drain, and drainage system. The paper considers the pressure-controlled hydrostatic transmission with hydraulic motor as an output link. It shows a possibility to create a saving hydraulic drive using a functional tie between the adjusting parameters of the pump and hydraulic motor through the pressure difference, torque, and angular rate of the hydraulic motor shaft rotation. The programmable logic controller can implement such tie. The Coulomb and viscous frictions are taken into consideration when developing a computational model of the hydraulic volume displacement drive. Discharge balance considers external and internal leakages in equivalent clearances of hydraulic machines, as well as compression loss volume caused by hydraulic fluid compressibility and deformation of pipe walls. To correct dynamic properties of hydraulic drive, the paper offers that in discharge balance are included the additional regulated external leakages in the open circuit of hydraulic drive and regulated internal leakages in the closed-loop circuit. Generalized differential equations having functional multipliers and multilinked nature have been obtained to describe the operation of hydraulic positioning and speed drive with two hydraulic volume adjustable working chamber machines. It is shown that a proposed computational model of hydraulic drive can be taken into consideration in development of LS («Load-Sensing» drives, in which the pumping pressure is tuned to the value required for the most loaded slave motor to overcome the load. Results attained can be used both in designing the industrial-purpose heavy

  6. Effect of Subsoil Compaction on Hydraulic Parameters

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Berisso, Feto Esimo; Schjønning, Per

    Soil compaction is a major threat to sustainable soil quality and is increasing since agricultural machinery is becoming heavier and is used more intensively. Compaction not only reduces pore volume, but also modifies the pore connectivity. The inter-Nordic research project POSEIDON (Persistent...... effects of subsoil compaction on soil ecological services and functions) put forward the hypothesis that due to a decrease in the hydraulic conductivity in the soil matrix, compaction increases the frequency of preferential flow events in macropores and therefore increases the leaching of otherwise....... In the field the near-saturated hydraulic conductivity was measured with a tension infiltrometer in the same treatments at a depth of 30 cm. In the laboratory saturated and near-saturated hydraulic conductivity and the bulk density were measured as well. Also, macropores in the large soil cores were made...

  7. Hydraulic characterization of hydrothermally altered Nopal tuff

    Energy Technology Data Exchange (ETDEWEB)

    Green, R.T.; Meyer-James, K.A. [Southwest Research Institute, San Antonio, TX (United States); Rice, G. [George Rice and Associates, San Antonio, TX (United States)

    1995-07-01

    Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow.

  8. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  9. Design of a hydraulic ash transport system

    Energy Technology Data Exchange (ETDEWEB)

    Mirgorodskii, V.G.; Mova, M.E.; Korenev, V.E.; Grechikhin, Yu.A. (Donetskii Politekhnicheskii Institut (USSR))

    1990-04-01

    Discusses general design of a hydraulic ash removal system to be employed at the reconstructed six 225 MW blocks of the Mironov State Regional Power Plant in the USSR. The blocks burn low-grade solid fuel with an ash content of up to 40.5%. Large quantities of ash have to be moved from the plant (total ash production 60 t/h, using 570 t/h of water for cooling and moistening). An optimum hydraulic ash transportation system would include a two-section airlift pumping system, shown in a diagram. Technological advantages of using this airlift system are enumerated, including short pipes, reduction in required water quantity and the possibility of siting hydraulic pumps at zero level.

  10. Hydraulic characterization of hydrothermally altered Nopal tuff

    International Nuclear Information System (INIS)

    Green, R.T.; Meyer-James, K.A.; Rice, G.

    1995-07-01

    Understanding the mechanics of variably saturated flow in fractured-porous media is of fundamental importance to evaluating the isolation performance of the proposed high-level radioactive waste repository for the Yucca Mountain site. Developing that understanding must be founded on the analysis and interpretation of laboratory and field data. This report presents an analysis of the unsaturated hydraulic properties of tuff cores from the Pena Blanca natural analog site in Mexico. The basic intent of the analysis was to examine possible trends and relationships between the hydraulic properties and the degree of hydrothermal alteration exhibited by the tuff samples. These data were used in flow simulations to evaluate the significance of a particular conceptual (composite) model and of distinct hydraulic properties on the rate and nature of water flow

  11. VVER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (author)

  12. WWER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (Authors)

  13. Hydraulic properties of alluvial soil of the ebb tide of Flocos Dam in Tuparetama - Pernambuco State, Brazil

    International Nuclear Information System (INIS)

    Souza, Eduardo S.; Montenegro, Abelardo A.A.

    2000-01-01

    The soil hydraulic properties, i.e., the soil-moisture characteristic curve, Θ(h), and the hydraulic conductivity, K(h), were determined for an alluvial soil from Flocos Dam, located at Tuparetama, state of Pernambuco, Brazil. The soil characteristic curves were determined through the functional adjustment, proposed by van Genuchten, to the values obtained in field measurements with tensiometers and neutron probes, and to values obtained in laboratory in a 'pressure pan' with a porous plate. The infiltration tests were performed for the depths of 0, 20, 40, 60, and 80 cm using an infiltration disk with a diameter of 80 mm, applying water at a potential of 0, -3, -6 and -12 cm. The hydraulic conductivity of the soil was determined through the VG method proposed by Zhang, which requires the previous knowledge of the soil-moisture characteristic curve. The determination of the soil-moisture characteristic curve by the two methods, using field or laboratory measurements, yielded similar results within the range of common pressure, from -300 to -100 cm, and indicates that the experimental results are sound and coherent. The heterogeneity of soil hydraulic properties within the soil profile can be explained by the variability in soil texture and dry bulk density throughout the profile. By using the diameter of the infiltration disk and the pressure applied to the soil, it was possible to characterize the porous matrix within the clayey layer. (author)

  14. Sharpening Sharpe Ratios

    OpenAIRE

    William N. Goetzmann; Jonathan E. Ingersoll Jr.; Matthew I. Spiegel; Ivo Welch

    2002-01-01

    It is now well known that the Sharpe ratio and other related reward-to-risk measures may be manipulated with option-like strategies. In this paper we derive the general conditions for achieving the maximum expected Sharpe ratio. We derive static rules for achieving the maximum Sharpe ratio with two or more options, as well as a continuum of derivative contracts. The optimal strategy has a truncated right tail and a fat left tail. We also derive dynamic rules for increasing the Sharpe ratio. O...

  15. Self-potential observations during hydraulic fracturing

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Jeffrey R.; Glaser, Steven D.

    2007-09-13

    The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with no water flow, a SP spike is observed that is caused by contact electrification. However, the time constant of this event is much less than that for transients observed during hydraulic fracturing, suggesting that SP created solely from material fracture does not contribute to the SP response during hydraulic fracturing.

  16. Hydraulic Properties related to Stream Reaeration

    Energy Technology Data Exchange (ETDEWEB)

    Tsivoglou, E. C.; Wallace, J. R. [School of Civil Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    1970-09-15

    The paper reports the results of recent and current field tracer experiments designed to investigate the relationships between the reaeration capacity of a flowing stream and the stream's hydraulic properties. The purpose of the studies is to develop models for the accurate prediction of stream reaeration capacity on the basis of observation of the associated hydraulic properties. The ability of a flowing stream to absorb oxygen from the overlying atmosphere is the principal process by which the stream is able to recover its dissolved oxygen resources once they have been depleted by bacterial degradation of organic wastes. Accurate knowledge of stream reaeration capacity is therefore a necessity in determining the required degree of waste treatment, and the associated costs, in any specific case. Oxygen absorption can only occur at the air-water interface, hence reaeration is a direct function of the rate of surface water replacement due to turbulent mixing. The latter is not directly observable, and so reaeration capacity has not been observable before the quite recent development of a gaseous radiotracer technique for field measurement of reaeration. This procedure involves the simultaneous use of three tracers, namely a fluorescent dye for time of flow, tritiated water for accurate dispersion measurement, and dissolved krypton-85 for measurement of gas transfer. Field results obtained by this technique are highly reproducible. Field tracer studies of the reaeration capacities of three medium-sized streams have been conducted over a total of about fifty river miles. Associated hydraulic properties such as stream flow, cross-sectional area, depth, velocity, hydraulic gradient and dispersion have also been measured. Features such as waterfalls, rapids and pools are included, and more than eighty observations of the reaeration capacities of individual stream reaches have been made. The paper reports the observed relationships between stream reaeration capacity and

  17. Hydraulic properties related to stream reaeration

    Energy Technology Data Exchange (ETDEWEB)

    Tsivoglou, E C; Wallace, J R [School of Civil Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

    1970-09-15

    The paper reports the results of recent and current field tracer experiments designed to investigate the relationships between the reaeration capacity of a flowing stream and the stream's hydraulic properties. The purpose of the studies is to develop models for the accurate prediction of stream reaeration capacity on the basis of observation of the associated hydraulic properties. The ability of a flowing stream to absorb oxygen from the overlying atmosphere is the principal process by which the stream is able to recover its dissolved oxygen resources once they have been depleted by bacterial degradation of organic wastes. Accurate knowledge of stream reaeration capacity is therefore a necessity in determining the required degree of waste treatment, and the associated costs, in any specific case. Oxygen absorption can only occur at the air-water interface, hence reaeration is a direct function of the rate of surface water replacement due to turbulent mixing. The latter is not directly observable, and so reaeration capacity has not been observable before the quite recent development of a gaseous radiotracer technique for field measurement of reaeration. This procedure involves the simultaneous use of three tracers, namely a fluorescent dye for time of flow, tritiated water for accurate dispersion measurement, and dissolved krypton-85 for measurement of gas transfer. Field results obtained by this technique are highly reproducible. Field tracer studies of the reaeration capacities of three medium-sized streams have been conducted over a total of about fifty river miles. Associated hydraulic properties such as stream flow, cross-sectional area, depth, velocity, hydraulic gradient and dispersion have also been measured. Features such as waterfalls, rapids and pools are included, and more than eighty observations of the reaeration capacities of individual stream reaches have been made. The paper reports the observed relationships between stream reaeration capacity and

  18. Beech (Fagus sylvatica L.) branches show acclimation of xylem anatomy and hydraulic properties to increased light after thinning

    OpenAIRE

    Lemoine, D.; Jacquemin, S.; Granier, A.

    2002-01-01

    International audience; Hydraulic acclimation of Fagus sylvatica L. was analysed in response to forest thinning. Several months after thinning, leaf and xylem water potential and stomatal conductance of thinned branches were compared to sun-exposed and shade branches. We characterised vulnerability to cavitation for branches taken from these three treatments. We compared effect of thinning on xylem anatomy (mean vessel diameter, vessel density). Thinned branches exhibited higher stomatal cond...

  19. Promoting water hydraulics in Malaysia: A green educational approach

    Science.gov (United States)

    Yusof, Ahmad Anas; Zaili, Zarin Syukri; Hassan, Siti Nor Habibah; Tuan, Tee Boon; Saadun, Mohd Noor Asril; Ibrahim, Mohd Qadafie

    2014-10-01

    In promoting water hydraulics in Malaysia, this paper presents research development of water hydraulics educational training system for secondary and tertiary levels in Malaysia. Water hydraulics trainer with robotic attachment has been studied in order to promote the usefulness of such educational tools in promoting sustainability and green technology in the country. The trainer is being developed in order to allow constructive curriculum development and continuous marketing research for the effectiveness and usefulness of using water in hydraulic power trainer. The research on water-based hydraulic trainer is now possible with the current development in water hydraulics technology.

  20. Effect of polyacrylamide on soil physical and hydraulic properties

    Science.gov (United States)

    Albalasmeh, Ammar; Gharaibeh, Mamoun; Hamdan, Enas

    2017-04-01

    The effect of polyacrylamide (PAM), as a soil conditioner, on selected soil physical and hydraulic properties (infiltration rate (f(t)), hydraulic conductivity (HC), soil moisture content, aggregate stability (AS), and soil aggregation) was studied. Two types of anionic PAM were used: Low molecular weight (LPAM) (1×105 g/mol) with medium charge density (33-43) and high molecular weight (HPAM) (1-6×106 g/mol) with medium charge density (33-43). Sandy loam soil was packed into plastic columns; PAM solutions at different concentrations (100, 250, 500, and 1000 mg L-1) were used every two weeks in four wetting and drying cycles. The highest infiltration rate value was 0.16 mm s-1 at 1000 mg/L low molecular weight PAM while the highest value of infiltration rate in high PAM molecular weight was 0.11 mm s-1 compared to the control (0.01 mm s-1). Soil HC was about 3.00 cm h-1 for LPAM at 1000 mg L-1 PAM, while the highest value for HPAM was about 2 cm h-1 for the same concentration, compared to the control. The amount of water that can be held by soil increased with the addition of PAM compared to the control. Differences in water content were more pronounced in LPAM compared to HPAM. The addition of LPAM increased aggregate stability proportional to PAM concentration. Moreover, 1000 mg L-1 produced the highest aggregate stability (19{%}) compared to HPAM and control (7{%} and 5{%}), respectively. As PAM concentration increased, the geometric mean diameter (GMD) increased for both PAM molecular weights compared to control (0.4 mm). At 1000 mg L-1 the GMD values were 0.88 mm and 0.79 mm for LPAM and HPAM, respectively. The addition of PAM improved soil physical and hydraulic properties, with an advantage to LPAM owing that to its ability to penetrate soil aggregates and therefore stabilizing them.

  1. Hydraulic modelling of the CARA Fuel element

    International Nuclear Information System (INIS)

    Brasnarof, Daniel O.; Juanico, Luis; Giorgi, M.; Ghiselli, Alberto M.; Zampach, Ruben; Fiori, Jose M.; Yedros, Pablo A.

    2004-01-01

    The CARA fuel element is been developing by the National Atomic Energy Commission for both Argentinean PHWRs. In order to keep the hydraulic restriction in their fuel channels, one of CARA's goals is to keep its similarity with both present fuel elements. In this paper is presented pressure drop test performed at a low-pressure facility (Reynolds numbers between 5x10 4 and 1,5x10 5 ) and rational base models for their spacer grid and rod assembly. Using these models, we could estimate the CARA hydraulic performance in reactor conditions that have shown to be satisfactory. (author) [es

  2. Mineral resource of the month: hydraulic cement

    Science.gov (United States)

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  3. Hydraulic efficiency of a Rushton turbine impeller

    Science.gov (United States)

    Chara, Z.; Kysela, B.; Fort, I.

    2017-07-01

    Based on CFD simulations hydraulic efficiency of a standard Rushton turbine impeller in a baffled tank was determined at a Reynolds number of ReM=33330. Instantaneous values of pressure and velocity components were used to draw up the macroscopic balance of the mechanical energy. It was shown that the hydraulic efficiency of the Rushton turbine impeller (energy dissipated in a bulk volume) is about 57%. Using this result we estimated a length scale in a non-dimensional equation of kinetic energy dissipation rate in the bulk volume as L=D/2.62.

  4. The hydraulics of the pressurized water reactors

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Barbier, D.; Caruso, A.

    1999-01-01

    The SFEN organized, the 10 june 1999 at Paris, a meeting in the domain of the PWR hydraulics and in particular the hydraulic phenomena concerning the vessel and the vapor generators. The papers presented showed the importance of the industrial stakes with their associated phenomena: cores performance and safety with the more homogenous cooling system, the rods and the control rods wear, the temperature control, the fluid-structure interactions. A great part was also devoted to the progresses in the domain of the numerical simulation and the models and algorithms qualification. (A.L.B.)

  5. Hydraulic regenerative system for a light vehicle

    OpenAIRE

    Orpella Aceret, Jordi; Guinart Trayter, Xavier

    2009-01-01

    The thesis is based in a constructed light vehicle that must be improved by adding a hydraulic energy recovery system. This vehicle named as TrecoLiTH, participated in the Formula Electric and Hybrid competition (Formula EHI) 2009 in Italy -Rome- and won several awards. This system consists in two hydraulic motors hub mounted which are used to store fluid at high pressure in an accumulator when braking. Through a valve the pressure will flow from the high pressure accumulator to the low press...

  6. A hydraulic device for unloading coke

    Energy Technology Data Exchange (ETDEWEB)

    Kretinin, M.V.; Abizgildin, U.M.; Kirillov, T.S.; Makarov, M.I.; Prokopov, O.I.; Solov' ev, A.M.

    1979-07-15

    A hydraulic device for unloading petroleum coke from slow carbonization chambers is characterized by an arrangement whereby in order to increase the output of large size coke by controlling the increment of the cutting line of the coke, the mechanism used to move the rod in the hydraulic cutter is built in the form of a rod rotation rotor; a gear wheel is mounted on the immobile section of this rotor, and on the mobile section a multi-stage regulator is installed. The drive gear of the regulator is engaged with the gear wheel, while the driven gear is connected to the rack, which is fastened to the rod.

  7. Observations on placentome diameters in gestating West African ...

    African Journals Online (AJOL)

    ADEYEYE

    2015-09-09

    /10.4314/sokjvs.v13i3.4. Observations on placentome diameters in gestating West. African dwarf does experimentally infected with Trypanosoma brucei. OO Leigh. Department of Veterinary Surgery and Reproduction, ...

  8. Porosity Assessment for Different Diameters of Coir Lignocellulosic Fibers

    Science.gov (United States)

    da Luz, Fernanda Santos; Paciornik, Sidnei; Monteiro, Sergio Neves; da Silva, Luiz Carlos; Tommasini, Flávio James; Candido, Verônica Scarpini

    2017-10-01

    The application of natural lignocellulosic fibers (LCFs) in engineering composites has increased interest in their properties and structural characteristics. In particular, the inherent porosity of an LCF markedly affects its density and the adhesion to polymer matrices. For the first time, both open and closed porosities of a natural LCF, for different diameter ranges, were assessed. Fibers extracted from the mesocarp of the coconut fruit were investigated by nondestructive methods of density measurements and x-ray microtomography (microCT). It was found that, for all diameter ranges, the closed porosity is significantly higher than the open porosity. The total porosity increases with diameter to around 60% for coir fibers with more than 503 μm in diameter. The amount and characteristics of these open and closed porosities were revealed by t test and Weibull statistics as well as by microCT.

  9. Heritability of retinal vessel diameters and blood pressure

    DEFF Research Database (Denmark)

    Taarnhøj, Nina C B B; Larsen, Michael; Sander, Birgit

    2006-01-01

    PURPOSE: To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics. METHODS: In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs......%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm...... for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values. CONCLUSIONS: In healthy young adults with normal blood pressure...

  10. Diameter modulation of vertically aligned single-walled carbon nanotubes.

    Science.gov (United States)

    Xiang, Rong; Einarsson, Erik; Murakami, Yoichi; Shiomi, Junichiro; Chiashi, Shohei; Tang, Zikang; Maruyama, Shigeo

    2012-08-28

    We demonstrate wide-range diameter modulation of vertically aligned single-walled carbon nanotubes (SWNTs) using a wet chemistry prepared catalyst. In order to ensure compatibility to electronic applications, the current minimum mean diameter of 2 nm for vertically aligned SWNTs is challenged. The mean diameter is decreased to about 1.4 nm by reducing Co catalyst concentrations to 1/100 or by increasing Mo catalyst concentrations by five times. We also propose a novel spectral analysis method that allows one to distinguish absorbance contributions from the upper, middle, and lower parts of a nanotube array. We use this method to quantitatively characterize the slight diameter change observed along the array height. On the basis of further investigation of the array and catalyst particles, we conclude that catalyst aggregation-rather than Ostwald ripening-dominates the growth of metal particles.

  11. Deriving muscle fiber diameter from recorded single fiber potential.

    Science.gov (United States)

    Zalewska, Ewa

    2017-12-01

    The aim of the study was to estimate muscle fiber diameters through analysis of single muscle fiber potentials (SFPs) recorded in the frontalis muscle of a healthy subject. Our previously developed analytical and graphic method to derive fiber diameter from the analysis of the negative peak duration and the amplitude of SFP, was applied to a sample of ten SFPs recorded in vivo. Muscle fiber diameters derived from the simulation method for the sample of frontalis muscle SFPs are consistent with anatomical data for this muscle. The results confirm the utility of proposed simulation method. Outlying data could be considered as the result of a contribution of other fibers to the potential recorded using an SFEMG electrode. Our graphic tool provides a rapid estimation of muscle fiber diameter. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

    Zhang, Hui; Dyrby, Tim B; Alexander, Daniel C

    2011-01-01

    This paper proposes a technique for a previously unaddressed problem, namely, mapping axon diameter in crossing fiber regions, using diffusion MRI. Direct measurement of tissue microstructure of this kind using diffusion MRI offers a new class of biomarkers that give more specific information about...... tissue than measures derived from diffusion tensor imaging. Most existing techniques for axon diameter mapping assume a single axon orientation in the tissue model, which limits their application to only the most coherently oriented brain white matter, such as the corpus callosum, where the single...... model to enable axon diameter mapping in voxels with crossing fibers. We show in simulation that the technique can provide robust axon diameter estimates in a two-fiber crossing with the crossing angle as small as 45 degrees. Using ex vivo imaging data, we further demonstrate the feasibility...

  13. Characteristic Length Scales in Fracture Networks: Hydraulic Connectivity through Periodic Hydraulic Tests

    Science.gov (United States)

    Becker, M.; Bour, O.; Le Borgne, T.; Longuevergne, L.; Lavenant, N.; Cole, M. C.; Guiheneuf, N.

    2017-12-01

    Determining hydraulic and transport connectivity in fractured bedrock has long been an important objective in contaminant hydrogeology, petroleum engineering, and geothermal operations. A persistent obstacle to making this determination is that the characteristic length scale is nearly impossible to determine in sparsely fractured networks. Both flow and transport occur through an unknown structure of interconnected fracture and/or fracture zones making the actual length that water or solutes travel undetermined. This poses difficulties for flow and transport models. For, example, hydraulic equations require a separation distance between pumping and observation well to determine hydraulic parameters. When wells pairs are close, the structure of the network can influence the interpretation of well separation and the flow dimension of the tested system. This issue is explored using hydraulic tests conducted in a shallow fractured crystalline rock. Periodic (oscillatory) slug tests were performed at the Ploemeur fractured rock test site located in Brittany, France. Hydraulic connectivity was examined between three zones in one well and four zones in another, located 6 m apart in map view. The wells are sufficiently close, however, that the tangential distance between the tested zones ranges between 6 and 30 m. Using standard periodic formulations of radial flow, estimates of storativity scale inversely with the square of the separation distance and hydraulic diffusivity directly with the square of the separation distance. Uncertainty in the connection paths between the two wells leads to an order of magnitude uncertainty in estimates of storativity and hydraulic diffusivity, although estimates of transmissivity are unaffected. The assumed flow dimension results in alternative estimates of hydraulic parameters. In general, one is faced with the prospect of assuming the hydraulic parameter and inverting the separation distance, or vice versa. Similar uncertainties exist

  14. Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shunchun, E-mail: epscyao@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); State Key Laboratory of Pulsed Power Laser Technology, Electronic Engineering Institute, Hefei 230037 (China); Xu, Jialong; Dong, Xuan; Zhang, Bo; Zheng, Jianping [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China)

    2015-08-01

    The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement.

  15. Fabrication of an Optical Fiber Micro-Sphere with a Diameter of Several Tens of Micrometers.

    Science.gov (United States)

    Yu, Huijuan; Huang, Qiangxian; Zhao, Jian

    2014-06-25

    A new method to fabricate an integrated optical fiber micro-sphere with a diameter within 100 µm, based on the optical fiber tapering technique and the Taguchi method is proposed. Using a 125 µm diameter single-mode (SM) optical fiber, an optical fiber taper with a cone angle is formed with the tapering technique, and the fabrication optimization of a micro-sphere with a diameter of less than 100 µm is achieved using the Taguchi method. The optimum combination of process factors levels is obtained, and the signal-to-noise ratio (SNR) of three quality evaluation parameters and the significance of each process factors influencing them are selected as the two standards. Using the minimum zone method (MZM) to evaluate the quality of the fabricated optical fiber micro-sphere, a three-dimensional (3D) numerical fitting image of its surface profile and the true sphericity are subsequently realized. From the results, an optical fiber micro-sphere with a two-dimensional (2D) diameter less than 80 µm, 2D roundness error less than 0.70 µm, 2D offset distance between the micro-sphere center and the fiber stylus central line less than 0.65 µm, and true sphericity of about 0.5 µm, is fabricated.

  16. Fabrication of an Optical Fiber Micro-Sphere with a Diameter of Several Tens of Micrometers

    Directory of Open Access Journals (Sweden)

    Huijuan Yu

    2014-06-01

    Full Text Available A new method to fabricate an integrated optical fiber micro-sphere with a diameter within 100 µm, based on the optical fiber tapering technique and the Taguchi method is proposed. Using a 125 µm diameter single-mode (SM optical fiber, an optical fiber taper with a cone angle is formed with the tapering technique, and the fabrication optimization of a micro-sphere with a diameter of less than 100 µm is achieved using the Taguchi method. The optimum combination of process factors levels is obtained, and the signal-to-noise ratio (SNR of three quality evaluation parameters and the significance of each process factors influencing them are selected as the two standards. Using the minimum zone method (MZM to evaluate the quality of the fabricated optical fiber micro-sphere, a three-dimensional (3D numerical fitting image of its surface profile and the true sphericity are subsequently realized. From the results, an optical fiber micro-sphere with a two-dimensional (2D diameter less than 80 µm, 2D roundness error less than 0.70 µm, 2D offset distance between the micro-sphere center and the fiber stylus central line less than 0.65 µm, and true sphericity of about 0.5 µm, is fabricated.

  17. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1985-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

  18. Detecting isotopic ratio outliers

    Science.gov (United States)

    Bayne, C. K.; Smith, D. H.

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

  19. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1986-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

  20. Catalytic growth of carbon nanotubes with large inner diameters

    Directory of Open Access Journals (Sweden)

    WEI REN ZHONG

    2005-02-01

    Full Text Available Carbon nanotubes (2.4 g/g catalyst, with large inner diameters were successfully synthesized through pyrolysis of methane on a Ni–Cu–Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of the carbon nanotubes prepared by this method is about 20–60 nm, while their outer diameter is about 40–80 nm. Transmission electron microscopy and X-ray diffraction were employed to investigate the morphology and microstructures of the carbon nanotubes. The analyses showed that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about a slight decrease in the methane conversion and the yield of carbon. The experimental results showed that sodium carbonate is a mildly toxic material which influenced the catalytic activity of the Ni–Cu–Al catalyst and resulted in the formation of carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.

  1. Effect of soil properties on Hydraulic characteristics under subsurface drip irrigation

    Science.gov (United States)

    Fan, Wangtao; Li, Gang

    2018-02-01

    Subsurface drip irrigation (SDI) is a technique that has a high potential in application because of its high efficiency in water-saving. The hydraulic characteristics of SDI sub-unit pipe network can be affected by soil physical properties as the emitters are buried in soils. The related research, however, is not fully explored. The laboratory tests were carried out in the present study to determine the effects of hydraulic factors including operating pressure, initial soil water content, and bulk density on flow rate and its sensitivity to each hydraulic factor for two types of SDI emitters (PLASSIM emitter and Heping emitter). For this purpose, three soils with contrasting textures (i.e., light sand, silt loam, and light clay) were repacked with two soil bulk density (1.25 and1.40 g cm-3) with two initial soil water content (12% and 18%) in plexiglass columns with 40 cm in diameter and 40 cm in height. Drip emitters were buried at depth of 20 cm to measure the flow rates under seven operating pressures (60, 100, 150, 200, 250, 300, and 370 kPa). We found that the operating pressure was the dominating factor of flow rate of the SDI emitter, and flow rate increased with the increase of operating pressure. The initial soil water content and bulk density also affected the flow rate, and their effects were the most notable in the light sand soil. The sensitivity of flow rate to each hydraulic factor was dependent on soil texture, and followed a descending order of light sand>silt loam>light clay for both types of emitters. Further, the sensitivity of flow rate to each hydraulic factor decreased with the increase of operating pressure, initial soil water content, and bulk density. This study may be used to guide the soil specific-design of SDI emitters for optimal water use and management.

  2. Reducing the environmental impact of hydraulic fracturing through design optimisation of positive displacement pumps

    International Nuclear Information System (INIS)

    Josifovic, Aleksandar; Roberts, Jennifer J.; Corney, Jonathan; Davies, Bruce; Shipton, Zoe K.

    2016-01-01

    The current approach to hydraulic fracturing requires large amounts of industrial hardware to be transported, installed and operated in temporary locations. A significant proportion of this equipment is comprised of the fleet of pumps required to provide the high pressures and flows necessary for well stimulation. Studies have shown that over 90% of the emissions of CO_2 and other pollutants that occur during a hydraulic fracturing operation are associated with these pumps. Pollution and transport concerns are of paramount importance for the emerging hydraulic fracturing industry in Europe, and so it is timely to consider these factors when assessing the design of high pressure pumps for the European resources. This paper gives an overview of the industrial plant required to carry out a hydraulic fracturing operation. This is followed by an analysis of the pump's design space that could result in improved pump efficiency. We find that reducing the plunger diameter and running the pump at higher speeds can increase the overall pump efficiency by up to 4.6%. Such changes to the pump's parameters would results in several environmental benefits beyond the obvious economic gains of lower fuel consumption. The paper concludes with a case study that quantifies these benefits. - Highlights: • We develop a parameterized model of hydraulic fracturing pumps. • We explore performance variation to optimise pump efficiency and performance. • New design could increase pump energy efficiency up to 4.6% and improve reliability. • The new design could also reduce environmental and social impacts of pumping. • This illustrates how optimised mechanical design can lower impacts and cost.

  3. On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

    2012-01-01

    Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

  4. Hydraulic pitch control system for wind turbines: Advanced modeling and verification of an hydraulic accumulator

    DEFF Research Database (Denmark)

    Irizar, Victor; Andreasen, Casper Schousboe

    2017-01-01

    Hydraulic pitch systems provide robust and reliable control of power and speed of modern wind turbines. During emergency stops, where the pitch of the blades has to be taken to a full stop position to avoid over speed situations, hydraulic accumulators play a crucial role. Their efficiency...... and capability of providing enough energy to rotate the blades is affected by thermal processes due to the compression and decompression of the gas chamber. This paper presents an in depth study of the thermodynamical processes involved in an hydraulic accumulator during operation, and how they affect the energy...

  5. Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature.

    Science.gov (United States)

    Wang, Liang; Yuan, Jin; Jiang, Hong; Yan, Wentao; Cintrón-Colón, Hector R; Perez, Victor L; DeBuc, Delia C; Feuer, William J; Wang, Jianhua

    2016-03-01

    This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, Psampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.

  6. Dynamic response characteristics evaluation of hydrostatic bearing in hydraulic piston pump/motor

    International Nuclear Information System (INIS)

    Ham, Young Bog; Yun, So Nam; Kim, Dong Soo; Choi, Byoung Oh; Kim, Sung Dong

    2001-01-01

    In swash plate type axial piston hydraulic pump and motor, the piston shoe is periodically pressurized with square function shape by supply pressure load as rotation of cylinder barrel. Therefore the recess pressure ono bottom part of piston shoe is suddenly increase through orifice in the piston shoe. In this study, we simulated that the frequency response of the recess pressure against with change of supply pressure with analysis tool. Also, we evaluate the dynamic response characteristics of overbalanced hydrostatic bearing with change of the orifice diameter

  7. Links between matrix bulk density, macropore characteristics and hydraulic behavior of soils

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Møldrup, Per; Lamandé, Mathieu

    2013-01-01

    characteristics on soil hydraulic functions has rarely been studied. With the objective of studying the links between these parameters we quantified macropore characteristics of intact soil columns (19 cm diameter x 20 cm high) from two agricultural field sites (Silstrup and Faardrup) in Denmark using coarse...... resolution X-ray CT and linked them with laboratory measurements of air permeability and leaching experiment. In addition to macropore characteristics, we also quantified the CT-number of the matrix as a measure of the bulk density of the matrix, i.e., excluding macropores in the soil. Soils from the two...

  8. Hydraulic Modular Dosaging Systems for Machine Drives

    Directory of Open Access Journals (Sweden)

    A. J. Kotlobai

    2005-01-01

    Full Text Available The justified principle of making modular dosaging systems for positive-displacement multimotor hydraulic drives used in running gear and technological equipment of mobile construction, road and agricultural machines makes it possible to synchronize motion of running parts. The examples of the realization of modular dosaging systems and an algorithm of their operation are given in the paper.

  9. Effect of Poroelasticity on Hydraulic Fracture Interactions

    DEFF Research Database (Denmark)

    Usui, Tomoya; Salimzadeh, Saeed; Paluszny, Adriana

    2017-01-01

    This study investigates, by performing finite element-based simulations, the influence of fluid leak-off and poroelasticity on growth of multiple hydraulic fractures that initiate from a single horizontal well. In this research, poroelastic deformation of the matrix is coupled with fluid flow in ...

  10. Control rod driving hydraulic pressure device

    International Nuclear Information System (INIS)

    Ishida, Kazuo.

    1990-01-01

    Discharged water after actuating control rod drives in a BWR type reactor is once discharged to a discharging header, then returned to a master control unit and, subsequently, discharged to a reactor by way of a cooling water header. The radioactive level in the discharging header and the master control unit is increased by the reactor water to increase the operator's exposure. In view of the above, a riser is disposed for connecting a hydraulic pressure control unit incorporating a directional control valve and the cooling water head. When a certain control rod is inserted, the pressurized driving water is supplied through a hydraulic pressure control unit to the control rod drives. The discharged water from the control rod drives is entered by way of the hydraulic pressure control unit into the cooling water header and then returned to the reactor by way of other hydraulic pressure control unit and the control rod drives. Thus, the reactor water is no more recycled to the master control unit to reduce the radioactive exposure. (N.H.)

  11. Hydraulic brake-system for a bicycle

    NARCIS (Netherlands)

    Van Frankenhuyzen, J.

    2007-01-01

    The invention relates to a hydraulic brake system for a bicycle which may or may not be provided with an auxiliary motor, comprising a brake disc and brake claws cooperating with the brake disc, as well as fluid-containing channels (4,6) that extend between an operating organ (1) and the brake

  12. Analyses of hydraulic performance of velocity caps

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Degn Eskesen, Mark Chr.; Buhrkall, Jeppe

    2014-01-01

    The hydraulic performance of a velocity cap has been investigated. Velocity caps are often used in connection with offshore intakes. CFD (computational fluid dynamics) examined the flow through the cap openings and further down into the intake pipes. This was combined with dimension analyses...

  13. Hydraulic urethral dilatation after optical internal urethrotomy ...

    African Journals Online (AJOL)

    Objectives: To determine the rate of early recurrence of urethral stricture in the first six months in patients who perform hydraulic urethral dilatation(HUD) after optical internal urethrotomy (OIU) and compare the early recurrence Fate in patients who perform HUD after OIU with the recurrence rates in patients reported in the ...

  14. Separation and pattern formation in hydraulic jumps

    DEFF Research Database (Denmark)

    Bohr, Tomas; Ellegaard, C.; Hansen, A. Espe

    1998-01-01

    We present theory and experiments on the circular hydraulic jump in the stationary regime. The theory can handle the situation in which the fluid flows over an edge far away from the jump. In the experiments the external height is controlled, and a series of transitions in the flow structure appe...

  15. Towards Autonomous Control of Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Conrad, Finn

    1998-01-01

    Presentation of new developed control algorithms to increase autonomy and intelligence of hydraulic control systems. A refinement of relaytuning method is used to determine the control parameters of a lag/lead controller and a poleplacement controller. Further, a fail-safe function is developed...

  16. Spiral groove seal. [for hydraulic rotating shaft

    Science.gov (United States)

    Ludwig, L. P. (Inventor)

    1973-01-01

    Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove pattern produces a pumping action toward the fluid when the shaft rotates which prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear.

  17. Hydraulic and hydrochemical characteristics of the phreatic ...

    African Journals Online (AJOL)

    Hydraulic and hydrochemical characteristics of the phreatic basement aquifers in parts of southwestern Nigeria. OA Idowu, O Martins, AM Gbadebo. Abstract. No Abstract. Journal of Mining and Geology Vol. 43 (1) 2007: pp. 71-78. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  18. Energy harvesting from hydraulic pressure fluctuations

    International Nuclear Information System (INIS)

    Cunefare, K A; Skow, E A; Erturk, A; Savor, J; Verma, N; Cacan, M R

    2013-01-01

    State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester. (paper)

  19. Sustainable hydraulic engineering through building with nature

    NARCIS (Netherlands)

    de Vriend, Huib J.; van Koningsveld, M.; Aarninkhof, S.G.J.; de Vries, Mindert; Baptist, M.J.

    2015-01-01

    Hydraulic engineering infrastructures are of concern to many people and are likely to interfere with the environment. Moreover, they are supposed to keep on functioning for many years. In times of rapid societal and environmental change this implies that sustainability and adaptability are important

  20. Power management in hydraulically actuated mobile equipment

    DEFF Research Database (Denmark)

    Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard

    2008-01-01

    The focus of the current paper is on the control of hydraulic systems when utilizing the advances that electronic control may bring with regard to power management, prioritized flow sharing and anti-stall, arising from being able to control both pump, valves and engine electronically. A simple mo...

  1. Hydraulic fracturing in anisotropic and heterogeneous rocks

    NARCIS (Netherlands)

    Valliappan, V.; Remmers, J.J.C.; Barnhoorn, A.; Smeulders, D.M.J.

    2017-01-01

    In this paper, we present a two dimensional model for modelling the hydraulic fracture process in anisotropic and heterogeneous rocks. The model is formulated using extended finite elements (XFEM) in combination with Newton-Raphson method for spatial and Euler's implicit scheme for time. The

  2. Hydraulic adjustment of Scots pine across Europe

    NARCIS (Netherlands)

    Martínez-Vilalta, J.; Cochard, H.; Mencuccini, M.; Sterck, F.J.; Herrero, A.; Korhonen, J.F.J.; Llorens, P.; Nikinmaa, E.; Nolè, A.; Poyatos, R.; Ripullone, F.; Sass-Klaassen, U.; Zweifel, R.

    2009-01-01

    The variability of branch-level hydraulic properties was assessed across 12 Scots pine populations covering a wide range of environmental conditions, including some of the southernmost populations of the species. The aims were to relate this variability to differences in climate, and to study the

  3. Massive hydraulic fracturing gas stimulation project

    International Nuclear Information System (INIS)

    Appledorn, C.R.; Mann, R.L.

    1977-01-01

    The Rio Blanco Massive Hydraulic Fracturing Project was fielded in 1974 as a joint Industry/ERDA demonstration to test the relative formations that were stimulated by the Rio Blanco Nuclear fracturing experiment. The project is a companion effort to and a continuation of the preceding nuclear stimulation project, which took place in May 1973. 8 figures

  4. Proceedings of the third nuclear thermal hydraulics meeting

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    This book contains the proceedings of the Thermal Hydraulics Division of the American Nuclear Society. The papers presented include: Simulator qualification using engineering codes and Development of thermal hydraulic analysis capabilities for Oyster Creek

  5. Chapter 12. Pure Tap Water Hydraulic Systems and Applications

    DEFF Research Database (Denmark)

    Conrad, Finn; Adelstorp, Anders

    1997-01-01

    Presentation of developed a modern pure tap water hydraulic components (Nessie), systems and industrial applications.......Presentation of developed a modern pure tap water hydraulic components (Nessie), systems and industrial applications....

  6. DCS Hydraulics Submittal, Otero County, New Mexico, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Hydraulics data includes spatial datasets and data tables necessary for documenting the hydraulic procedures for computing flood elevations for a flood insurance...

  7. Analysis of INDOT current hydraulic policies : [technical summary].

    Science.gov (United States)

    2011-01-01

    Hydraulic design often tends to be on a conservative side for safety reasons. Hydraulic structures are typically oversized with the goal being reduced future maintenance costs, and to reduce the risk of property owner complaints. This approach leads ...

  8. Applicability estimation of flowmeter logging for detecting hydraulic pass

    International Nuclear Information System (INIS)

    Miyakawa, Kimio; Tanaka, Yasuji; Tanaka, Kazuhiro

    1997-01-01

    Estimation of the hydraulic pass governing hydrogeological structure contributes significantly to the siting HLW repository. Flowmeter logging can detect hydraulic passes by measuring vertical flow velocity of groundwater in the borehole. We reviewed application of this logging in situ. The hydraulic pass was detected with combination of ambient flow logging, with pumping and/or injecting induced flow logging. This application showed that the flowmeter logging detected hydraulic passes conveniently and accurately compared with other hydraulic tests. Hydraulic conductivity by using flowmeter logging was assessed above 10 -6 m/sec and within one order from comparison with injection packer tests. We suggest that appropriate application of the flowmeter logging for the siting is conducted before hydraulic tests because test sections and monitoring sections are decided rationally for procurement of quantitative hydraulic data. (author)

  9. Determination of mechanical and hydraulic properties of PVA hydrogels.

    Science.gov (United States)

    Kazimierska-Drobny, Katarzyna; El Fray, Miroslawa; Kaczmarek, Mariusz

    2015-03-01

    In this paper the identification of mechanical and hydraulic parameters of poly(vinyl alcohol) (PVA) hydrogels is described. The identification method follows the solution of inverse problem using experimental data from the unconfined compression test and the poroelastic creep model. The sensitivity analysis of the model shows significant dependence of the creep curves on investigated parameters. The hydrogels containing 22% PVA and 25% PVA were tested giving: the drained Youngs modulus of 0.71 and 0.9MPa; the drained Poisson's ratio of 0.18 and 0.31; and the permeability of 3.64·10(-15) and 3.29·10(15)m(4)/Ns, respectively. The values of undrained Youngs modulus were determined by measuring short period deformation of samples in the unconfined tests. A discussion on obtained results is presented. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. A clustering analysis of lipoprotein diameters in the metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Frazier-Wood Alexis C

    2011-12-01

    Full Text Available Abstract Background The presence of smaller low-density lipoproteins (LDL has been associated with atherosclerosis risk, and the insulin resistance (IR underlying the metabolic syndrome (MetS. In addition, some research has supported the association of very low-, low- and high-density lipoprotein (VLDL HDL particle diameters with components of the metabolic syndrome (MetS, although this has been the focus of less research. We aimed to explore the relationship of VLDL, LDL and HDL diameters to MetS and its features, and by clustering individuals by their diameters of VLDL, LDL and HDL particles, to capture information across all three fractions of lipoprotein into a unified phenotype. Methods We used nuclear magnetic resonance spectroscopy measurements on fasting plasma samples from a general population sample of 1,036 adults (mean ± SD, 48.8 ± 16.2 y of age. Using latent class analysis, the sample was grouped by the diameter of their fasting lipoproteins, and mixed effects models tested whether the distribution of MetS components varied across the groups. Results Eight discrete groups were identified. Two groups (N = 251 were enriched with individuals meeting criteria for the MetS, and were characterized by the smallest LDL/HDL diameters. One of those two groups, one was additionally distinguished by large VLDL, and had significantly higher blood pressure, fasting glucose, triglycerides, and waist circumference (WC; P Conclusions While small LDL diameters remain associated with IR and the MetS, the occurrence of these in conjunction with a shift to overall larger VLDL diameter may identify those with the highest fasting glucose, TG and WC within the MetS. If replicated, the association of this phenotype with more severe IR-features indicated that it may contribute to identifying of those most at risk for incident type II diabetes and cardiometabolic disease.

  11. Failure Diameter of PBX 9502: Simulations with the SURFplus model

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-03

    SURFplus is a reactive burn model for high explosives aimed at modelling shock initiation and propagation of detonation waves. It utilizes the SURF model for the fast hot-spot reaction plus a slow reaction for the energy released by carbon clustering. A feature of the SURF model is that there is a partially decoupling between burn rate parameters and detonation wave properties. Previously, parameters for PBX 9502 that control shock ini- tiation had been calibrated to Pop plot data (distance-of-run to detonation as a function of shock pressure initiating the detonation). Here burn rate parameters for the high pres- sure regime are adjusted to t the failure diameter and the limiting detonation speed just above the failure diameter. Simulated results are shown for an uncon ned rate stick when the 9502 diameter is slightly above and slightly below the failure diameter. Just above the failure diameter, in the rest frame of the detonation wave, the front is sonic at the PBX/air interface. As a consequence, the lead shock in the neighborhood of the interface is supported by the detonation pressure in the interior of the explosive rather than the reaction immediately behind the front. In the interior, the sonic point occurs near the end of the fast hot-spot reaction. Consequently, the slow carbon clustering reaction can not a ect the failure diameter. Below the failure diameter, the radial extent of the detonation front decreases starting from the PBX/air interface. That is, the failure starts at the PBX boundary and propagates inward to the axis of the rate stick.

  12. Diameter measurements of polystyrene particles with atomic force microscopy

    International Nuclear Information System (INIS)

    Garnaes, J

    2011-01-01

    The size of (nano) particles is a key parameter used in controlling their function. The particle size is also important in order to understand their physical and chemical properties and regulate their number in health and safety issues. In this work, the geometric diameters of polystyrene spheres of nominal diameter 100 nm are measured using atomic force microscopy. The measurements are based on the apex height and on the average distance between neighbouring spheres when they form a close-packed monolayer on a flat mica substrate. The most important influence parameters for the determination of the geometric diameter are the lateral air gaps and deformation of the spheres. The lateral air gaps are caused by significant size variations of the individual spheres, and a correction is calculated based on the simulation of packing of spheres. The deformation of the spheres is caused mainly by capillary forces acting when they are in contact with each other or with the mica substrate. Based on calculated capillary forces and the literature values of the elastic properties of the polystyrene and mica, the deformation is estimated to be 2 nm with a standard uncertainty of 2 nm. The geometric diameter of the polystyrene spheres was measured with a combined standard uncertainty of ≈3 nm. The measured vertical diameter of 92.3 nm and the certified mobility equivalent diameter measured by differential mobility analysis (DMA) are marginally consistent at a confidence level of 95%. However, the measured lateral geometric diameter was 98.9 nm and is in good agreement with DMA

  13. Experimental Investigation on Hydraulic Properties of Granular Sandstone and Mudstone Mixtures

    Directory of Open Access Journals (Sweden)

    Dan Ma

    2018-01-01

    Full Text Available The caved zone during longwall mining has high permeability, resulting in a mass of groundwater storage which causes a threat of groundwater inrush hazard to the safe mining. To investigate the hazard mechanism of granular sandstone and mudstone mixture (SMM in caved zone, this paper presents an experimental study on the effect of sandstone particle (SP and mudstone particle (MP weight ratio on the non-Darcy hydraulic properties evolution. A self-designed granular rock seepage experimental equipment has been applied to conduct the experiments. The variation of particle size distribution was induced by loading and water seepage during the test, which indicated that the particle crushing and erosion properties of mudstone were higher than those of sandstone. Porosity evolution of SMM was strongly influenced by loading (sample height and SP/MP weight ratio. The sample with higher sample height and higher weight ratio of SP achieved higher porosity value. In particular, a non-Darcy equation, for hydraulic properties (permeability κ and non-Darcy coefficient ζ calculation, was sufficient to fit the relation between the hydraulic gradient and seepage velocity. The test results indicated that, due to the absence and narrowing of fracture and void during loading, the permeability κ decreases and the non-Darcy coefficient ζ increases. The variation of the hydraulic properties of the sample within the same particle size and SP/MP weight ratio indicated that groundwater inrush hazard showed a higher probability of occurrence in sandstone strata and crushed zone (e.g., faults. Moreover, isolated fractures and voids were able to achieve the changeover from self-extension to interconnection at the last loading stage, which caused the fluctuation tendency of κ and ζ. Fluctuation ability in mudstone was higher than that in sandstone. The performance of an empirical model was also investigated for the non-Darcy hydraulic properties evolution prediction of

  14. The advantages of hydraulic packing extraction

    International Nuclear Information System (INIS)

    Baker, R.S.

    1991-01-01

    Today's competitive environment, coupled with industry's desire to improve the efficiency of plant maintenance and operations, has management continually seeking ways to save time, money, and, at nuclear plants, radiation exposure. One area where a tremendous improvement in efficiency can be realized is valve packing removal. For example, industry experience indicates that up to 70% of the time it takes to repack a valve can be spent just removing the old packing. In some case, the bonnets of small valves are removed to facilitate packing removal and prevent stem and stuffing box damage that can occur when using packing removal picks. In other cases, small valves are simply removed and discarded because it costs less to replace the valves than to remove the packing using conventional methods. Hydraulic packing extraction greatly reduces packing removal time and will not damage the stem nor stuffing box, thus eliminating the need for bonnet removal or valve replacement. This paper will review some of the more common problems associated with manual packing extraction techniques. It will explain how hydraulic packing extraction eliminates or greatly reduces the impact of each of the problem areas. A discussion will be provided of some actual industry operating experiences related to success stories using hydraulic packing extraction. The paper will also briefly describe the operating parameters associated with hydraulic packing extraction tools. Throughout the paper, actual operating experiences from the nuclear power, fossil power, petrochemical, and refinery industries will be used to support the conclusion that hydraulic packing extraction is an alternative that can save time, money, and exposure

  15. Understanding, Classifying, and Selecting Environmentally Acceptable Hydraulic Fluids

    Science.gov (United States)

    2016-08-01

    traditional mineral oil; therefore, the life cycle costs over time may be reduced . REPLACEMENT OF EXISTING HYDRAULIC FLUIDS: Hydraulic fluids in existing...properly maintaining the fluid can extend the time interval between fluid changes, thus reducing the overall operating cost of the EA hydraulic fluid. It...Environmentally Acceptable Hydraulic Fluids by Timothy J. Keyser, Robert N. Samuel, and Timothy L. Welp INTRODUCTION: On a daily basis, the United States Army

  16. Review of fluid and control technology of hydraulic wind turbines

    Science.gov (United States)

    Cai, Maolin; Wang, Yixuan; Jiao, Zongxia; Shi, Yan

    2017-09-01

    This study examines the development of the fluid and control technology of hydraulic wind turbines. The current state of hydraulic wind turbines as a new technology is described, and its basic fluid model and typical control method are expounded by comparing various study results. Finally, the advantages of hydraulic wind turbines are enumerated. Hydraulic wind turbines are expected to become the main development direction of wind turbines.

  17. Review of fluid and control technology of hydraulic wind turbines

    Institute of Scientific and Technical Information of China (English)

    Maolin CAI; Yixuan WANG; Zongxia JIAO; Yan SHI

    2017-01-01

    This study examines the development of the fluid and control technology of hydraulic wind turbines.The current state of hydraulic wind turbines as a new technology is described,and its basic fluid model and typical control method are expounded by comparing various study results.Finally,the advantages of hydraulic wind turbines are enumerated.Hydraulic wind turbines are expected to become the main development direction of wind turbines.

  18. Critical review of hydraulic modeling on atmospheric heat dissipation

    International Nuclear Information System (INIS)

    Onishi, Y.; Brown, S.M.

    1977-01-01

    Objectives of this study were: to define the useful roles of hydraulic modeling in understanding the predicting atmospheric effects of heat dissipation systems; to assess the state-of-the-art of hydraulic modeling of atmospheric phenomena; to inventory potentially useful existing hydraulic modeling facilities both in the United States and abroad; and to scope hydraulic model studies to assist the assessment of atmospheric effects of nuclear energy centers

  19. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....... hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...

  20. On the performance of small diameter gas cyclones

    International Nuclear Information System (INIS)

    Halasz, Marcos Roberto Teixeira

    2002-02-01

    Small diameter cyclones represent a potential alternative for the removal of small diameter particles from gaseous mixtures as well as the environmental control of their emission. In order to establish feasible configurations of a small diameter cyclone applied in the separation of solid particles dispersed in a gas and considering a large quantify of experimental data in literature, neural networks were used to estimate the equipment grade efficiency and pressure drop. In order to evaluate a performance of many small diameters configurations and analysis was carried of parametrical sensibility which determines the most important variables on separation efficiency determination. A set of experimental runs was carried out in a lab-scale mini-cyclone in order to obtain the separation efficiency and pressure drop for different configurations, and evaluate the feasibility of coupling a post-cyclone device to improve the equipment overall performance. The cyclones used presented diameters of 0.03 and 0.05 m and the remaining dimensions varied proportionally about those found in Stairmand high-efficiency cyclones. Experimental separation efficiencies up to 99% were obtained in this work. These results confirm the feasibility of the experimental set-up configuration proposed. (author)