WorldWideScience

Sample records for maximum cylinder pressure

  1. Pressure cylinders under fire condition

    Directory of Open Access Journals (Sweden)

    Jan Hora

    2016-03-01

    Full Text Available The presence of pressure cylinders under fire conditions significantly increases the risk rate for the intervening persons. It is considerably problematic to predict the pressure cylinders behaviour during heat exposition, its destruction progress and possible following explosion of the produced air–gas mixture because pressure cylinders and its environment generate a highly complicated dynamic system during an uncontrolled destruction. The large scale tests carried out by the Pilsen Fire and Rescue Department and the Rapid Response Unit of the Czech Republic Police in October 2012 and in May 2014 in the Military area Brdy and in the area of the former Lachema factory in Kaznějov had several objectives, namely, to record, qualify and quantify some of the aspects of an uncontrolled heat destruction procedure of an exposed pressure cylinder in an enclosed space and to qualify and describe the process of a controlled destruction of a pressure cylinder by shooting through it including basic tactical concepts. The article describes the experiments that were carried out.

  2. Robust cylinder pressure estimation in heavy-duty diesel engines

    NARCIS (Netherlands)

    Kulah, S.; Forrai, A.; Rentmeester, F.; Donkers, T.; Willems, F.P.T.

    2017-01-01

    The robustness of a new single-cylinder pressure sensor concept is experimentally demonstrated on a six-cylinder heavy-duty diesel engine. Using a single-cylinder pressure sensor and a crank angle sensor, this single-cylinder pressure sensor concept estimates the in-cylinder pressure traces in the

  3. 76 FR 38697 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2011-07-01

    ... imports from China of high pressure steel cylinders, provided for in subheading 7311.00.00 of the... threatened with material injury by reason of LTFV and subsidized imports of high pressure steel cylinders... contained in USITC Publication 4241 (July 2011), entitled High Pressure Steel Cylinders from China...

  4. A cylinder pressure based engine management system

    Energy Technology Data Exchange (ETDEWEB)

    Truscott, A.; Noble, A. [Ricardo Consulting Engineers Ltd. (United Kingdom); Mueller, R.; Hart, M.; Kroetz, G.; Eickhoff, M. [DaimlerChrysler AG (Germany); Cavalloni, C.; Gnielka, M. [Kistler Instrumente AG (Switzerland)

    2000-07-01

    Worldwide demands on fuel economy and lower emissions from automotive vehicles have led to stringent requirements in the development of Engine Management Systems (EMS). Cylinder Pressure based Engine Management Systems (CPEMS) provide a way forward in EMS technology by combining intelligent control algorithms with innovative sensing techniques. The full utilisation of model-based control and diagnostics to provide improvements in cost, efficiency, emissions and comfort requires the close monitoring of engine conditions. This is made possible with the advent of new inexpensive sensor materials that can withstand the harsh environment of the combustion chamber. AENEAS is a collaborative project undertaken by Ricardo, DaimlerChrysler and Kistler, with financial support from the European Commission and the Swiss Government, aimed at demonstrating the major benefits of CPEMS technology. This paper describes the application of CPEMS technology to a spark ignition (SI) engine. It describes how the combination of model based algorithms, incorporating physical principles, and cylinder pressure sensing can provide an effective means of engine control and diagnostics. Results are presented to demonstrate the benefits of this new technology. (author)

  5. 77 FR 37712 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2012-06-22

    ...), that an industry in the United States is materially injured by reason of imports of high pressure steel... preliminary determinations by Commerce that imports of high pressure steel cylinders from China were... Publication 4328 (June 2012), entitled High Pressure Steel Cylinders from China: Investigation Nos. 701-TA-480...

  6. Optimization of In-Cylinder Pressure Filter for Engine Research

    Science.gov (United States)

    2017-06-01

    ARL-TR-8034 ● JUN 2017 US Army Research Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth...Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth S Kim, Michael T Szedlmayer, Kurt M Kruger, and Chol-Bum M...

  7. Experimental and finite element prediction of bursting pressure in compound cylinders

    International Nuclear Information System (INIS)

    Majzoobi, G.H.; Farrahi, G.H.; Pipelzadeh, M.K.; Akbari, A.

    2004-01-01

    Aluminium cylinders with a constant ratio of outer to inner radii, k=2.2, with different diametral interferences and various shrinkage radii were subjected to bursting and autofrettage pressures. Numerical simulations of the compound cylinders were also performed using the finite element code, NISA. The results can predict the optimum shrinkage radius to a reasonable accuracy with the use of finite element analysis. This radius corresponds to the situation when the maximum von-Mises stress at the internal radii of both the inner and outer cylinders become equal. It was shown that the maximum von-Mises stress across the wall of the cylinder is at the minimum at this shrinkage radius. The optimum diametral interference was found to be that which sufficiently brought the contact surface of the inner and outer cylinders to the point of yielding. Should the shrinkage pressure exceed the elastic limit, the pressure capacity of the cylinder will not be improved. The numerical and experimental results show that autofrettage had no effect on the bursting pressure of the thick-walled compound cylinder for the material tested

  8. 76 FR 33239 - High Pressure Steel Cylinders From the People's Republic of China; Initiation of Countervailing...

    Science.gov (United States)

    2011-06-08

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel... countervailing duty (``CVD'') petition concerning imports of high pressure steel cylinders (``steel cylinders... of Antidumping Duties and Countervailing Duties on High Pressure Steel Cylinders from the People's...

  9. UF{sub 6} pressure excursions during cylinder heating

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    As liquid UF{sub 6} inside a cylinder changes from a liquid to a solid, it forms a porous solid which occupies approximately the same volume as that of the liquid before cooling. Simultaneously as the liquid cools, UF{sub 6} vapor in the cylinder ullage above the liquid desublimes on the upper region of the inner cylinder wall. This solid is a dense, glass-like material which can accumulate to a significant thickness. The thickness of the solid coating on the upper cylinder wall and directly behind the cylinder valve area will vary depending on the conditions during the cooling stage. The amount of time lapsed between UF{sub 6} solidification and UF{sub 6} liquefaction can also affect the UF{sub 6} coating. This is due to the daily ambient heat cycle causing the coating to sublime from the cylinder wall to cooler areas, thus decreasing the thickness. Structural weakening of the dense UF{sub 6} layer also occurs due to cylinder transport vibration and thermal expansion. During cylinder heating, the UF{sub 6} nearest the cylinder wall will liquefy first. As the solid coating behind the cylinder valve begins to liquefy, it results in increased pressure depending upon the available volume for expansion. At the Paducah Gaseous Diffusion Plant (PGDP) during the liquefaction of the UF{sub 6} in cylinders in the UF{sub 6} feed and sampling autoclaves, this pressure increase has resulted in the activation of the systems rupture discs which are rated at 100 pounds per square inch differential.

  10. Bursting pressure of autofrettaged cylinders with inclined external cracks

    International Nuclear Information System (INIS)

    Seifi, Rahman; Babalhavaeji, Majid

    2012-01-01

    Autofrettaging a pressure vessel improves its pressure capacity. This is reliable if there isn’t any crack or other type of flaws. In this paper, the effects of external surface cracks on bursting pressure of autofrettaged cylinders are studied. It is observed that bursting pressure decreases considerably (up to 30%) due to external cracks in the cylinders without autofrettage. This reduction increases for high levels of the applied autofrettage. External axial cracks have more effects than inclined cracks. Comparing experimental and numerical results show that the numerical methods can acceptably predict the bursting pressure of the autofrettaged cracked cylinders. These predictions are valid when the fracture parameter (J-Integral) is calculated from the modified equation that takes into account the effects of residual stresses. - Highlights: ► Modified J-Integral can be used for study of autofrettaged cracked cylinders. ► External axial cracks reduce considerably the pressure capacity of cylinders. ► External circumferential cracks have not considerable effects on bursting pressure. ► Autofrettage has contrary effects on external crack in compared with internal crack.

  11. Bursting pressure of autofrettaged cylinders with inclined external cracks

    Energy Technology Data Exchange (ETDEWEB)

    Seifi, Rahman, E-mail: rseifi@basu.ac.ir [Mechanical Engineering Department, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Babalhavaeji, Majid [Mechanical Engineering Department, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

    2012-01-15

    Autofrettaging a pressure vessel improves its pressure capacity. This is reliable if there isn't any crack or other type of flaws. In this paper, the effects of external surface cracks on bursting pressure of autofrettaged cylinders are studied. It is observed that bursting pressure decreases considerably (up to 30%) due to external cracks in the cylinders without autofrettage. This reduction increases for high levels of the applied autofrettage. External axial cracks have more effects than inclined cracks. Comparing experimental and numerical results show that the numerical methods can acceptably predict the bursting pressure of the autofrettaged cracked cylinders. These predictions are valid when the fracture parameter (J-Integral) is calculated from the modified equation that takes into account the effects of residual stresses. - Highlights: Black-Right-Pointing-Pointer Modified J-Integral can be used for study of autofrettaged cracked cylinders. Black-Right-Pointing-Pointer External axial cracks reduce considerably the pressure capacity of cylinders. Black-Right-Pointing-Pointer External circumferential cracks have not considerable effects on bursting pressure. Black-Right-Pointing-Pointer Autofrettage has contrary effects on external crack in compared with internal crack.

  12. Dual-fuel engine with cylinder pressure based control

    Energy Technology Data Exchange (ETDEWEB)

    Ritscher, Bert [Caterpillar Motoren GmbH und Co. KG, Kiel (Germany). Large Power Systems Div.

    2013-10-15

    Cylinder pressure sensors were initially used to detect knocking and misfiring on spark ignited gas engines. On its latest MaK brand dual-fuel engine, Caterpillar Motoren is harnessing the deep insights into combustion and engine condition that can be derived direct from the origin of engine power in sophisticated control, monitoring and diagnostic systems. (orig.)

  13. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

    Hansen, M.R.; Andersen, T.O.

    2010-01-01

    This paper is concerned with the inherent oscillatory nature of pressure compensated velocity control of a hydraulic cylinder subjected to a negative load and suspended by means of an over-center valve. Initially, a linearized stability analysis of such a hydraulic circuit is carried out clearly ...... in a nonlinear time domain simulation model validating the linear stability analysis....

  14. Photoelastic investigation of the stresses in a stepped cylinder under internal pressure

    International Nuclear Information System (INIS)

    Sawa, Yoshiaki; Nishida, Masataka

    1985-01-01

    The states of stress distribution of the stepped cylinder under inner-pressure are studied by means of stress freezing photoelastic method. The experimental results reveal that fiber stress concentration occurs on the circular arc and hoop stress concentration occurs at the jointing point of the straight line and the arc and that each maximum value of fiver stress and hoop stress depends very greatly on the diameter of a small cylinder and the radius of curvature. And the relationship between the stress concentration factors and these shape factors are given. Effects of wall thickness on the stress concentration factors are also determined. (author)

  15. Experimental strength evaluation of cylinders with a flat head subjected to internal pressure at elevated temperature

    International Nuclear Information System (INIS)

    Suzuki, Mitsuru; Makino, Yutaka

    1978-01-01

    The experiments using component test models such as a cylinder with a flat head and F.E.M. elastic analyses to investigate the secondary stress, peak stress and creep-fatigue interaction effect are described. The comparison of uniaxial stress with multiaxial stress about deformation and strength at elevated temperatures are also described here. The results of experiments and analysis are summarized as follows: (1) The maximum stress as the equivalent stress is the most suitable for the prediction of the creep failure life of cylinders subjected to internal pressure using the uniaxial creep test results. And the Mises's equivalent stress is the suitable for this prediction using the data of the onset of the uniaxial tertiary creep. (2) In the creep characteristics of the cylinder there, is no tertiary creep stage, and the rupture elongation of the cylinder accords with the elongation of the onset of the uniaxial tertiary creep. (3) It was recognized that the secondary stress occurred at the corner of the cylinder with a flat head has a little effect on creep and creep-fatigue life. (4) The life reduction effect due to the creep-fatigue interaction around the corner was recognized by the linear damage rule and compared with the value of Code Case 1592. (5) A difference of failure modes by imposed conditions for vessel with the size-discontinuity section was recognized by the cyclic internal pressure tests with hold time. (author)

  16. 76 FR 77964 - High Pressure Steel Cylinders From the People's Republic of China: Preliminary Determination of...

    Science.gov (United States)

    2011-12-15

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... determines that high pressure steel cylinders (``steel cylinders'') from the People's Republic of China... Imposition of Antidumping and Countervailing Duties: High Pressure Steel Cylinders From the People's Republic...

  17. 78 FR 55059 - High Pressure Steel Cylinders from the People's Republic of China: Rescission of Countervailing...

    Science.gov (United States)

    2013-09-09

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel... duty order on high pressure steel cylinders (cylinders) from the People's Republic of China (PRC) for... High Pressure Steel Cylinders from the People's Republic of China.'' \\3\\ See BTIC's August 23, 2013...

  18. 77 FR 37384 - High Pressure Steel Cylinders From the People's Republic of China: Countervailing Duty Order

    Science.gov (United States)

    2012-06-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel...''), the Department is issuing a countervailing duty order on high pressure steel cylinders (``steel... investigation of steel cylinders from the PRC. See High Pressure Steel Cylinders From the People's Republic of...

  19. Relationship of pressure to temperature rise in overfilled cylinders

    International Nuclear Information System (INIS)

    Barber, E.J.

    1979-01-01

    Mild steel pressure vessels containing uranium hexafluoride are heated in 96-inch diameter autoclaves to allow the feed material to enter the gaseous diffusion process equipment for enrichment in the uranium 235 isotope. For purposes of safety analysis it is necessary to establish the ability of the instrumentation to shut off the steam supply to the autoclave prior to cylinder rupture if the cylinder has been overfilled. To make this determination requires estimates of the rate of change of pressure with respect to change of temperature at constant volume as a function of the temperature at which the ullage disappears. The paper presents the calculations for the estimation of this rate of change for liquid uranium hexafluoride using the ratio of the coefficients of expansion and compressibility using empirical liquid density data and the Eyring equation of state for liquids. 5 figs. (MB)

  20. Stress distribution and pressure-bearing capacity of a high-pressure split-cylinder die with prism cavity

    Science.gov (United States)

    Zhao, Liang; Li, Mingzhe; Wang, Liyan; Qu, Erhu; Yi, Zhuo

    2018-03-01

    A novel high-pressure belt-type die with a split-type cylinder is investigated with respect to extending its lifetime and improving its pressure bearing capacity. Specifically, a tungsten carbide cylinder is split into several parts along the radial direction with a prism-type cavity. In this paper, the cylinders with different split numbers are chosen to study the stress distribution and compare them with the traditional belt-type die. The simulation results indicate that the split cylinder has much smaller stress than those in the belt-type cylinder, and the statistical analysis reveals that the split-pressure cylinder is able to bear higher pressure. Experimental tests also show that the high-pressure die with a split cylinder and prism cavity has a stronger pressure-bearing capacity than a belt-type die. The split cylinder has advantages of easy manufacturing, high pressure bearing capacity, and replaceable performance.

  1. Piston cylinder cell for high pressure ultrasonic pulse echo measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kepa, M. W., E-mail: mkepa@staffmail.ed.ac.uk; Huxley, A. D. [SUPA, Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Ridley, C. J.; Kamenev, K. V. [Centre for Science at Extreme Conditions and School of Engineering, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)

    2016-08-15

    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe{sub 2}.

  2. Diesel Combustion and Emission Using High Boost and High Injection Pressure in a Single Cylinder Engine

    Science.gov (United States)

    Aoyagi, Yuzo; Kunishima, Eiji; Asaumi, Yasuo; Aihara, Yoshiaki; Odaka, Matsuo; Goto, Yuichi

    Heavy-duty diesel engines have adopted numerous technologies for clean emissions and low fuel consumption. Some are direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler systems, and strong steel pistons. Using these technologies, diesel engines have achieved an extremely low CO2 emission as a prime mover. However, heavy-duty diesel engines with even lower NOx and PM emission levels are anticipated. This study achieved high-boost and lean diesel combustion using a single cylinder engine that provides good engine performance and clean exhaust emission. The experiment was done under conditions of intake air quantity up to five times that of a naturally aspirated (NA) engine and 200MPa injection pressure. The adopted pressure booster is an external supercharger that can control intake air temperature. In this engine, the maximum cylinder pressure was increased and new technologies were adopted, including a monotherm piston for endurance of Pmax =30MPa. Moreover, every engine part is newly designed. As the boost pressure increases, the rate of heat release resembles the injection rate and becomes sharper. The combustion and brake thermal efficiency are improved. This high boost and lean diesel combustion creates little smoke; ISCO and ISTHC without the ISNOx increase. It also yields good thermal efficiency.

  3. 77 FR 37377 - High Pressure Steel Cylinders From the People's Republic of China: Antidumping Duty Order

    Science.gov (United States)

    2012-06-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... Department is issuing an antidumping duty order on high pressure steel cylinders from the People's Republic... determination of material injury to a U.S. industry.\\1\\ \\1\\ See High Pressure Steel Cylinders from China...

  4. 76 FR 64301 - High Pressure Steel Cylinders From the People's Republic of China: Preliminary Affirmative...

    Science.gov (United States)

    2011-10-18

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel... producers and exporters of high pressure steel cylinders from the People's Republic of China. For... initiation in the Federal Register. See High Pressure Steel Cylinders From the People's Republic of China...

  5. 77 FR 26738 - High Pressure Steel Cylinders From the People's Republic of China: Final Affirmative...

    Science.gov (United States)

    2012-05-07

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel... producers and exporters of high pressure steel cylinders (steel cylinders) from the People's Republic of... The following events have occurred since the Preliminary Determination.\\1\\ \\1\\ See High Pressure Steel...

  6. 76 FR 33213 - High Pressure Steel Cylinders from the People's Republic of China: Initiation of Antidumping Duty...

    Science.gov (United States)

    2011-06-08

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977)] High Pressure Steel... (``Department'') received a petition concerning imports of high pressure steel cylinders (``steel cylinders...\\ (``Petitioner''). See Petitions for the Imposition of Antidumping and Countervailing Duties: High Pressure Steel...

  7. Reduction of Erosion Wear of Mean Pressure Cylinder of Steam Turbines Operating Beyond Critical Parameters

    Directory of Open Access Journals (Sweden)

    V. P. Kascheev

    2009-01-01

    Full Text Available The paper considers problems leading to erosion wear of flowing part of a mean pressure turbine cylinder operating beyond critical parameters. Explanation of erosion wear of flowing part of a mean pressure turbine cylinder which is proved in practice and recommendations for wear reduction are given in the paper

  8. 77 FR 3281 - High Pressure Steel Cylinders From China; Scheduling of the Final Phase of Countervailing Duty...

    Science.gov (United States)

    2012-01-23

    ...)] High Pressure Steel Cylinders From China; Scheduling of the Final Phase of Countervailing Duty and... retarded, by reason of subsidized and less-than-fair-value imports from China of high pressure steel... (``high pressure steel cylinders''). High pressure steel cylinders are fabricated of chrome alloy steel...

  9. Effect of instantaneous rotational speed on the analysis of measured diesel engine cylinder pressure data

    International Nuclear Information System (INIS)

    Antonopoulos, Antonis K.; Hountalas, Dimitrios T.

    2012-01-01

    Highlights: ► The effect of in-cycle speed fluctuation on cylinder pressure measurement is investigated. ► A phasing error is introduced when sampling cylinder pressure at constant time intervals. ► The phasing error increases with the increase of engine load and decrease of engine speed. ► Measurement using constant sampling rate affects estimation of HRR, ignition angle etc. - Abstract: Diesel engine cylinder pressure measurements are widely used in field and lab applications to support among other control, monitoring and diagnostic applications. There are two methods to measure cylinder pressure, the use of a crank angle encoder, which guarantees pressure samples at fixed crank angles, and the use of constant time sampling rate. The last is frequently used due to its simplicity or because of practical restrictions. However, in order to perform thermodynamic calculations it is necessary to attribute a crank angle value to each measured pressure value. But if the in-cycle rotational speed fluctuates and this is neglected, an error will result in the values derived from the processing of the measured cylinder pressure. For this reason in the present work an experimental investigation is conducted on a single cylinder diesel test engine to identify the aforementioned problem. During the tests cylinder pressure and instantaneous speed were recorded using an accurate crank angle reference. These where then used to simulate the measurement of cylinder pressure digitized using a fixed time step. The comparison of the two cylinder pressure traces and the thermodynamic parameters derived from them, reveals the introduction of an error which depends on engine load and speed.

  10. Stresses from pressure, radial, and moment loads in cylinder-to-cylinder vessel by a finite plate method

    International Nuclear Information System (INIS)

    Brown, S.J.; Fox, M.E.

    1977-08-01

    A structural problem that has received continued interest and development over the last several decades is the determination of stresses in two normally intersecting cylindrical shells subjected to internal pressure and external loading. In nuclear pressure vessels the external loading of the vessel through the attachment is encountered in thermal interaction, seismic loading and various postulated rupture or failure mechanisms. A simple technique, the Finite Plate Method, (FPM) is presented to analyze stresses in cylinder-to-cylinder junctures. The approach uses shallow shell formulations and a three term series expansion plate formulation, which limits the range of applicability. It is felt that the value of the method is its accuracy, economy, and ease in modeling a structure which falls within the range of applicability. Another appealing feature of the method is that its simplistic approach of superposition of results permits an easy extension to include additional loads not treated. For those mechanical loadings not developed, it is felt that their effect can either be accounted for by the mechanisms discussed or by simple calculations. Generally, the stresses resulting from torsional or transverse shear are small compared to the loads discussed, however, these shear effects may be included. Finally, in the instance of thermal stress within the cylinder-to-cylinder structure, it has been shown in an unpublished study by Brown that the FPM yields very good results for the range of curvatures discussed

  11. 49 CFR 195.406 - Maximum operating pressure.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum operating pressure. 195.406 Section 195.406 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... HAZARDOUS LIQUIDS BY PIPELINE Operation and Maintenance § 195.406 Maximum operating pressure. (a) Except for...

  12. 77 FR 1060 - High Pressure Steel Cylinders From the People's Republic of China: Postponement of Final...

    Science.gov (United States)

    2012-01-09

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... (``Department'') initiated an antidumping duty investigation on high pressure steel cylinders from the People's... investigation is currently due 75 days after the date of the Preliminary Determination.\\3\\ \\1\\ See High Pressure...

  13. 76 FR 59658 - High Pressure Steel Cylinders From the People's Republic of China: Postponement of Preliminary...

    Science.gov (United States)

    2011-09-27

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... (``Department'') initiated an antidumping duty investigation on high pressure steel cylinders from the People's... for this investigation is currently due no later than October 18, 2011. \\1\\ See High Pressure Steel...

  14. Structural behaviour of a welded superalloy cylinder with internal pressure in a high temperature environment

    International Nuclear Information System (INIS)

    Udoguchi, T.; Nakanishi, T.

    1981-01-01

    Steady and cyclic creep tests with internal pressure were performed at temperatures of 800 to 1000 0 C on Hastelloy X cylinders with and without a circumferential Tungsten Inert Gas (TIG) welding technique. The creep rupture strength of the TIG welded cylinders was much lower than that of the non-welded cylinders whilst creep rupture strength reduction by the TIG technique was not observed in uniaxial creep tests. The reason for the low creep strength of welded cylinders is discussed and it is noted that the creep ductility of weld metal plays an essentially important role. In order to improve the creep strength of the TIG welded cylinder, various welding procedures with assorted weld metals were investigated. Some improvements were obtained by using welding techniques which had either Incoloy 800 or a modified Hastelloy X material as the filler metal. (U.K.)

  15. Engine cylinder pressure reconstruction using crank kinematics and recurrently-trained neural networks

    Science.gov (United States)

    Bennett, C.; Dunne, J. F.; Trimby, S.; Richardson, D.

    2017-02-01

    A recurrent non-linear autoregressive with exogenous input (NARX) neural network is proposed, and a suitable fully-recurrent training methodology is adapted and tuned, for reconstructing cylinder pressure in multi-cylinder IC engines using measured crank kinematics. This type of indirect sensing is important for cost effective closed-loop combustion control and for On-Board Diagnostics. The challenge addressed is to accurately predict cylinder pressure traces within the cycle under generalisation conditions: i.e. using data not previously seen by the network during training. This involves direct construction and calibration of a suitable inverse crank dynamic model, which owing to singular behaviour at top-dead-centre (TDC), has proved difficult via physical model construction, calibration, and inversion. The NARX architecture is specialised and adapted to cylinder pressure reconstruction, using a fully-recurrent training methodology which is needed because the alternatives are too slow and unreliable for practical network training on production engines. The fully-recurrent Robust Adaptive Gradient Descent (RAGD) algorithm, is tuned initially using synthesised crank kinematics, and then tested on real engine data to assess the reconstruction capability. Real data is obtained from a 1.125 l, 3-cylinder, in-line, direct injection spark ignition (DISI) engine involving synchronised measurements of crank kinematics and cylinder pressure across a range of steady-state speed and load conditions. The paper shows that a RAGD-trained NARX network using both crank velocity and crank acceleration as input information, provides fast and robust training. By using the optimum epoch identified during RAGD training, acceptably accurate cylinder pressures, and especially accurate location-of-peak-pressure, can be reconstructed robustly under generalisation conditions, making it the most practical NARX configuration and recurrent training methodology for use on production engines.

  16. Method and apparatus for reconstructing in-cylinder pressure and correcting for signal decay

    Science.gov (United States)

    Huang, Jian

    2013-03-12

    A method comprises steps for reconstructing in-cylinder pressure data from a vibration signal collected from a vibration sensor mounted on an engine component where it can generate a signal with a high signal-to-noise ratio, and correcting the vibration signal for errors introduced by vibration signal charge decay and sensor sensitivity. The correction factors are determined as a function of estimated motoring pressure and the measured vibration signal itself with each of these being associated with the same engine cycle. Accordingly, the method corrects for charge decay and changes in sensor sensitivity responsive to different engine conditions to allow greater accuracy in the reconstructed in-cylinder pressure data. An apparatus is also disclosed for practicing the disclosed method, comprising a vibration sensor, a data acquisition unit for receiving the vibration signal, a computer processing unit for processing the acquired signal and a controller for controlling the engine operation based on the reconstructed in-cylinder pressure.

  17. Experimental study of the pressure discharge process for the hydraulic control rod drive system stepped cylinder

    International Nuclear Information System (INIS)

    Wang, Jinhua; Bo, Hanliang; Zheng, Wenxiang

    2002-01-01

    The pressure discharge process from the stepped cylinder of the Hydraulic Control Rod Drive System (HCRDS) was studied experimentally in the HCRDS experimental loop for the 200 MW Nuclear Heating Reactor (NHR-200). The results showed that the differential pressure between the outside and the inside of the stepped cylinder increased rapidly to the desired value so that the force induced by the differential pressure which pushes the out tube of stepped cylinder was large enough. Therefore, if the hydraulic control rod were jammed, the pressure could push the hydraulic control rod to overcome the frictional resistance to insert the control rod into the reactor core. The experimental results verified that this design would solve the problem of hydraulic control rod jamming during an accident. (author)

  18. Buckling behaviour of imperfect ring-stiffened cone-cylinder intersections under internal pressure

    International Nuclear Information System (INIS)

    Zhao, Y.

    2005-01-01

    Cone-cylinder intersections are used commonly in pressure vessels and piping. In the case of a cone large end-to-cylinder intersection under internal pressure, the intersection is subject to a large circumferential compressive force. While both the cone and the cylinder may be locally thickened to strengthen the intersection, it is often desirable and convenient to provide an annular plate ring at the cone-to-cylinder joint to supplement local thickening or as an alternative strengthening measure, leading to a ring-stiffened cone-cylinder intersection. Only limited work has been carried out specifically on ring-stiffened cone-cylinder intersections under internal pressure. This paper presents the first experimental study on such intersections. In addition to the presentation of test results including geometric imperfections, failure behaviour and the determination of buckling mode and load based on displacement measurements, results from nonlinear bifurcation analysis using the perfect shape and nonlinear analysis using the measured imperfect shape are presented and compared with the experimental results

  19. In-cylinder pressure resonance analysis for trapped mass estimation in automotive engines

    OpenAIRE

    Bares Moreno, Pau

    2017-01-01

    This thesis presents a new application for in-cylinder pressure sensors in internal combustion engines. The new method takes profit of the high-frequency content of the in-cylinder pressure signal to determine the speed of sound evolution during the expansion stroke and combines this estimation with the low-frequency content of the pressure signal and a volume estimation to obtain a measurement of the trapped mass. The new method is based on the studies of the resonance phenomenon in pent...

  20. Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement

    Energy Technology Data Exchange (ETDEWEB)

    Desantes, J.M.; Galindo, J.; Guardiola, C.; Dolz, V. [CMT - Motores Termicos, Universidad Politecnica de Valencia (Spain)

    2010-01-15

    Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementing standard methods. Present paper uses in cylinder pressure increase during the intake stroke for inferring the trapped air mass. The method is validated on two different turbocharged diesel engines and compared with the standard methods. (author)

  1. AWWA C303-17 concrete pressure pipe, bar-wrapped, steel-cylinder type

    CERN Document Server

    2017-01-01

    This standard describes the manufacture of concrete pressure pipe, reinforced with a steel cylinder that is helically wrapped with mild steel bar reinforcement, in sizes ranging from 10 in. through 72 in. (250 mm through 1,830 mm), inclusive, and for working pressures up to 400 psi (2,760 kPa).

  2. 76 FR 28807 - High Pressure Steel Cylinders From China; Institution of Antidumping and Countervailing Duty...

    Science.gov (United States)

    2011-05-18

    ... the United States is materially retarded, by reason of imports from China of High Pressure Steel... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-480 and 731-TA-1188 (Preliminary)] High Pressure Steel Cylinders From China; Institution of Antidumping and Countervailing Duty Investigations and...

  3. 78 FR 55679 - High Pressure Steel Cylinders From the People's Republic of China; Rescission of the 2011-2013...

    Science.gov (United States)

    2013-09-11

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... antidumping duty order on high pressure steel cylinders from the People's Republic of China (``PRC'') for the... order on high pressure steel cylinders from the PRC.\\1\\ In response, on July 1, 2013, Beijing Tianhai...

  4. Prediction model of velocity field around circular cylinder over various Reynolds numbers by fusion convolutional neural networks based on pressure on the cylinder

    Science.gov (United States)

    Jin, Xiaowei; Cheng, Peng; Chen, Wen-Li; Li, Hui

    2018-04-01

    A data-driven model is proposed for the prediction of the velocity field around a cylinder by fusion convolutional neural networks (CNNs) using measurements of the pressure field on the cylinder. The model is based on the close relationship between the Reynolds stresses in the wake, the wake formation length, and the base pressure. Numerical simulations of flow around a cylinder at various Reynolds numbers are carried out to establish a dataset capturing the effect of the Reynolds number on various flow properties. The time series of pressure fluctuations on the cylinder is converted into a grid-like spatial-temporal topology to be handled as the input of a CNN. A CNN architecture composed of a fusion of paths with and without a pooling layer is designed. This architecture can capture both accurate spatial-temporal information and the features that are invariant of small translations in the temporal dimension of pressure fluctuations on the cylinder. The CNN is trained using the computational fluid dynamics (CFD) dataset to establish the mapping relationship between the pressure fluctuations on the cylinder and the velocity field around the cylinder. Adam (adaptive moment estimation), an efficient method for processing large-scale and high-dimensional machine learning problems, is employed to implement the optimization algorithm. The trained model is then tested over various Reynolds numbers. The predictions of this model are found to agree well with the CFD results, and the data-driven model successfully learns the underlying flow regimes, i.e., the relationship between wake structure and pressure experienced on the surface of a cylinder is well established.

  5. Cylinder-Pressure Based Injector Calibration for Diesel Engines

    OpenAIRE

    König, Johan

    2008-01-01

    One way of complying with future emission restrictions for diesel engines is to use pressure sensors for improved combustion control. Implementation of pressure sensors into production engines would lead to new possibilities for fuel injection monitoring where one potential use is injector calibration. The scope of this thesis is to investigate the possibility of using pressure sensors for finding the minimal energizing time necessary for fuel injection. This minimal energizing time varies ov...

  6. Integrated pressure sensor systems in the cylinder-head gasket; Integrierte Drucksensorik in der Zylinderkopfdichtung

    Energy Technology Data Exchange (ETDEWEB)

    Diez, A.; Maier, U. [ElringKlinger AG (Germany); Eifler, G. [ElringKlinger Motortechnik GmbH (Germany); Schnepf, M. [Kistler Instrumente AG, Winterthur (Switzerland)

    2004-01-01

    The optimisation of engine management plays a major role in the development of modern engines. A significant contribution to this optimisation will be made by a cylinder-head gasket with integrated pressure sensors of the quality required to measure in-cylinder pressure, which ElringKlinger AG together with Kistler Instrumente AG are currently working on. The goal is to provide the automotive industry with a system that makes it possible to optimally control combustion in each individual cylinder. (orig.) [German] Die Optimierung des Motormanagements spielt bei der Entwicklung moderner Motoren eine zentrale Rolle. Eine Zylinderkopfdichtung mit integrierten Druckaufnehmern in Indizierqualitaet, an der die Elring-Klinger AG und die Kistler Instrumente AG derzeit gemeinsam arbeiten, soll hierzu einen entscheidenden Beitrag leisten. Ziel ist es, der Automobilindustrie ein System zur Verfuegung zu stellen, das eine optimierte und zylinderindividuelle Steuerung der Verbrennung ermoeglicht. (orig.)

  7. On propagation of axisymmetric waves in pressurized functionally graded elastomeric hollow cylinders

    Science.gov (United States)

    Wu, Bin; Su, Yipin; Liu, Dongying; Chen, Weiqiu; Zhang, Chuanzeng

    2018-05-01

    Soft materials can be designed with a functionally graded (FG) property for specific applications. Such material inhomogeneity can also be found in many soft biological tissues whose functionality is only partly understood to date. In this paper, we analyze the axisymmetric guided wave propagation in a pressurized FG elastomeric hollow cylinder. The cylinder is subjected to a combined action of axial pre-stretch and pressure difference applied to the inner and outer cylindrical surfaces. We consider both torsional waves and longitudinal waves propagating in the FG cylinder made of incompressible isotropic elastomer, which is characterized by the Mooney-Rivlin strain energy function but with the material parameters varying with the radial coordinate in an affine way. The pressure difference generates an inhomogeneous deformation field in the FG cylinder, which dramatically complicates the superimposed wave problem described by the small-on-large theory. A particularly efficient approach is hence employed which combines the state-space formalism for the incremental wave motion with the approximate laminate or multi-layer technique. Dispersion relations for the two types of axisymmetric guided waves are then derived analytically. The accuracy and convergence of the proposed approach is validated numerically. The effects of the pressure difference, material gradient, and axial pre-stretch on both the torsional and the longitudinal wave propagation characteristics are discussed in detail through numerical examples. It is found that the frequency of axisymmetric waves depends nonlinearly on the pressure difference and the material gradient, and an increase in the material gradient enhances the capability of the pressure difference to adjust the wave behavior in the FG cylinder. This work provides a theoretical guidance for characterizing FG soft materials by in-situ ultrasonic nondestructive evaluation and for designing tunable waveguides via material tailoring along

  8. 49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the minimum... 49 Transportation 3 2010-10-01 2010-10-01 false Maximum and minimum allowable operating pressure...

  9. Using the adaptive SMA composite cylinder concept to reduce radial dilation in composite pressure vessels

    Science.gov (United States)

    Paine, Jeffrey S.; Rogers, Craig A.

    1995-05-01

    Composite materials are widely used in the design of pressurized gas and fluid vessels for applications ranging from underground gasoline storage tanks to rocket motors for the space shuttle. In the design of a high pressure composite vessel (Pi > 12 Ksi), thick-wall (R/h short term dilation and long term creep are not problematic for applications requiring only the containment of the pressurized fluid. In applications where metallic liners are required, however, substantial dilation and creep causes plastic yielding which leads to reduced fatigue life. To applications such as a hydraulic accumulator, where a piston is employed to fit and seal the fluid in the composite cylinder, the dilation and creep may allow leakage and pressure loss around the piston. A concept called the adaptive composite cylinder is experimentally presented. Shape memory alloy wire in epoxy resin is wrapped around or within polymer matrix composite cylinders to reduce radial dilation of the cylinder. Experimental results are presented that demonstrate the ability of the SMA wire layers to reduce radial dilation. Results from experimental testing of the recovery stress fatigue response of nitinol shape memory alloy wires is also presented.

  10. Virtual cylinder pressure sensor for transient operation in heavy-duty engines

    NARCIS (Netherlands)

    Kulah, S.; Donkers, M.C.F.; Willems, F.P.T.

    2015-01-01

    Cylinder pressure-based combustion control is widely introduced for passenger cars. Benefits include enhanced emission robustness to fuel quality variation, reduced fuel consumption due to more accurate (multi-pulse) fuel injection, and minimized after treatment size. In addition, it enables the

  11. Virtual Cylinder Pressure Sensor for Transient Operation in Heavy-Duty Engines

    NARCIS (Netherlands)

    Kulah, S.; Donkers, T.; Willems, F.

    2015-01-01

    Cylinder pressure-based combustion control is widely introduced for passenger cars. Benefits include enhanced emission robustness to fuel quality variation, reduced fuel consumption due to more accurate (multi-pulse) fuel injection, and minimized after treatment size.In addition, it enables the

  12. Banana regime pressure anisotropy in a bumpy cylinder magnetic field

    International Nuclear Information System (INIS)

    Garcia-Perciante, A.L.; Callen, J.D.; Shaing, K.C.; Hegna, C.C.

    2006-01-01

    The pressure anisotropy is calculated for a plasma in a bumpy cylindrical magnetic field in the low collisionality (banana) regime for small magnetic-field modulations (ε≡ΔB/2B parallel is then calculated and is shown to exceed the flux-surface-averaged parallel viscous force parallel > by a factor of O(1/ε). A high-frequency limit (ω>>ν) for the pressure anisotropy is also determined and the calculation is then extended to include the full frequency dependence by using an expansion in Cordey eigenfunctions

  13. Control of the thermostressed state of low-pressure cylinder rotors for power steam turbines

    International Nuclear Information System (INIS)

    Lejzerovich, A.Sh.

    1980-01-01

    The principle arrangement of an analog device for operation control of the low pressure cylinder (LPC) heating at large steam turbine start-up has been developed. Different forms of representation of the thermal conductivity equation used for realization by means of analog models are analized. Presented are the results of calculating the heating indices for the welded rotor of LPC during the turbine start-up from a cold state and the curves of temperature distribution in the disc of the first sections of welded LPC rotor at start-up from a cold state and in a steady-state regime. The results obtained show that in the process of start-up the error of the temperature difference DELTAt determination according to the suggested scheme does not exceed 10 deg C. After achieving the maximum of DELTAt in the process of the rotor temperature field flattening, this error increases and constitutes 32 deg C in steady-state regime, mainly, due to the error of temperature determination on the rotation axis in controlled cross section. As far as the control for the LPC rotor heating is necessary only during start-up and the requirements for its accuracy are not equivalent, therefore, for all regimes, representativity and accuracy of control provided by the accepted calculation scheme is quite satisfactory

  14. Effect of Training Frequency on Maximum Expiratory Pressure

    Science.gov (United States)

    Anand, Supraja; El-Bashiti, Nour; Sapienza, Christine

    2012-01-01

    Purpose: To determine the effects of expiratory muscle strength training (EMST) frequency on maximum expiratory pressure (MEP). Method: We assigned 12 healthy participants to 2 groups of training frequency (3 days per week and 5 days per week). They completed a 4-week training program on an EMST trainer (Aspire Products, LLC). MEP was the primary…

  15. 49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

  16. Self adaptive internal combustion engine control for hydrogen mixtures based on piezoelectric dynamic cylinder pressure transducers

    International Nuclear Information System (INIS)

    Courteau, R.; Bose, T.K.

    2004-01-01

    Piezoelectric transducers offer an effective, non-intrusive way to monitor dynamic cylinder pressure in internal combustion engines. Devices dedicated to this purpose are appearing on the market, often in the form of spark plugs with embedded piezo elements. Dynamic cylinder pressure is typically used to provide diagnostic functions, or to help map an engine after it is designed. With the advent of powerful signal processor chips, it is now possible to embed enough computing power in the engine controller to perform auto tuning based on the signals provided by such transducers. Such functionality is very useful if the fuel characteristics vary between fill ups, as is often the case with alternative fuels. We propose here an algorithm for self-adaptive tuning based on a Kalman filter operating on a few selected metrics of the dynamic pressure curve. (author)

  17. Creep strength of hastelloy X TIG-welded cylinder under internal pressure at elevated temperature

    International Nuclear Information System (INIS)

    Udoguchi, Teruyoshi; Indo, Hirosato; Isomura, Kazuyuki; Kobatake, Kiyokazu; Nakanishi, Tsuneo.

    1981-01-01

    Creep tests on circumferentially TIG-welded Hastelloy x cylinders were carried out under internal pressure for the investigation of structural behavior of welded components in high temperature environment. The creep rupture strength of TIG-welded cylinders was much lower than that of non-welded cylinders, while such reduction was not found in uniaxial creep tests on TIG-welded bars. It was deduced that the reduction was due to the low ductility (ranging from 1 to 5%) of the weld metal to which enhanced creep was induced by the adjacent base metal whose creep strain rate was much higher than that of the weld metal. Therefore, uniaxial creep tests on bar specimens is not sufficient for proper assessment of the creep rupture strength of welded components. Both creep strain rate and creep ductility should be concerned for the assessment. Creep tests by using components such as cylinder under internal pressure are recommendable for the confirmation of creep strength of welded structures and components. (author)

  18. Analytical Investigation of Elastic Thin-Walled Cylinder and Truncated Cone Shell Intersection Under Internal Pressure

    OpenAIRE

    Zamani, J.; Soltani, B.; Aghaei, M.

    2014-01-01

    An elastic solution of cylinder-truncated cone shell intersection under internal pressure is presented. The edge solution theory that has been used in this study takes bending moments and shearing forces into account in the thin-walled shell of revolution element. The general solution of the cone equations is based on power series method. The effect of cone apex angle on the stress distribution in conical and cylindrical parts of structure is investigated. In addition, the effect of the inter...

  19. Shakedown analysis of thick-walled cylinders subjected to internal pressure with the unified strength criterion

    International Nuclear Information System (INIS)

    Xu Shuanqiang; Yu Maohong

    2005-01-01

    Most previous studies on shakedown of thick-walled cylinders were based on the assumption that the compressive and tensile strengths of the materials were identical. In this paper the shakedown of an internally pressurized cylinder made of a material with a strength-difference and intermediate principal stress effects is dealt with by using a unified strength criterion which consists of a family of convex piecewise linear strength criteria. Through an elasto-plastic analysis the solutions for the loading stresses, residual stresses, elastic limit, plastic limit and shakedown limit of the cylinder are derived. It is shown that the present solutions include the classical plasticity solutions as special cases and have the ability to account for the strength-difference and intermediate principal stress effects. Finally, the influence of the two effects on the shakedown limit of the cylinder is investigated. The results show that the shakedown limit depends on the two effects and is underestimated if these effects are neglected as in the classical plasticity solution based on the Tresca criterion

  20. Storage in pressurized cylinders of Kr adsorbed on activated carbon. Fundamental principles

    International Nuclear Information System (INIS)

    Henrion, P.N.; Greff, J.F. de; Claes, W.; Leurs, A.

    1979-01-01

    Pressure of a few kg/cm 2 cause considerable adsorption of krypton on charcoal. In presence of this adsorbent, the aspects of krypton storage in a pressurized cylinder are modified in such a way that, eventually, a simplified engineered storage can be based on this procedure. As fission krypton generates heat and since the amount adsorbed is a function of temperature and pressure, there is no easy way of assessing the value of this concept. The purpose of this study was therefore to review the types of charcoal commercially available to examine their properties as adsorbents, as well as the thermal conductivity and the packing efficiency obtainable in beds made of these materials. The ways in which data are measured or estimated are explained in some detail. Heat transfer was evaluated by a simple mathematical model and, by means of selected values from the above data, realistic examples were treated, leading to explicit relationships between wall temperature, pressure and useful krypton load. Influence of krypton specific activity ( 85 Kr dilution) was also examined. The pressure vessels diameter is however of fundamental importance. The authors strongly recommend the use of specially designed, light-weight, relatively narrow pressure cylinders

  1. Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device.

    Science.gov (United States)

    Utanohara, Yuri; Hayashi, Ryo; Yoshikawa, Mineka; Yoshida, Mitsuyoshi; Tsuga, Kazuhiro; Akagawa, Yasumasa

    2008-09-01

    It is clinically important to evaluate tongue function in terms of rehabilitation of swallowing and eating ability. We have developed a disposable tongue pressure measurement device designed for clinical use. In this study we used this device to determine standard values of maximum tongue pressure in adult Japanese. Eight hundred fifty-three subjects (408 male, 445 female; 20-79 years) were selected for this study. All participants had no history of dysphagia and maintained occlusal contact in the premolar and molar regions with their own teeth. A balloon-type disposable oral probe was used to measure tongue pressure by asking subjects to compress it onto the palate for 7 s with maximum voluntary effort. Values were recorded three times for each subject, and the mean values were defined as maximum tongue pressure. Although maximum tongue pressure was higher for males than for females in the 20-49-year age groups, there was no significant difference between males and females in the 50-79-year age groups. The maximum tongue pressure of the seventies age group was significantly lower than that of the twenties to fifties age groups. It may be concluded that maximum tongue pressures were reduced with primary aging. Males may become weaker with age at a faster rate than females; however, further decreases in strength were in parallel for male and female subjects.

  2. Self adaptive internal combustion engine control for hydrogen mixtures based on piezoelectric dynamic cylinder pressure transducers

    Energy Technology Data Exchange (ETDEWEB)

    Courteau, R.; Bose, T. K. [Universite du Quebec a Trois-Rivieres, Hydrogen Research Institute, Trois-Rivieres, PQ (Canada)

    2004-07-01

    An algorithm for self-adaptive tuning of an internal combustion engine is proposed, based on a Kalman filter operating on a few selected metrics of the dynamic pressure curve. Piezoelectric transducers are devices to monitor dynamic cylinder pressure; spark plugs with embedded piezo elements are now available to provide diagnostic engine functions. Such transducers are also capable of providing signals to the engine controller to perform auto tuning, a function that is considered very useful particularly in vehicles using alternative fuels whose characteristics frequently show variations between fill-ups. 2 refs., 2 figs.

  3. Approximation for maximum pressure calculation in containment of PWR reactors

    International Nuclear Information System (INIS)

    Souza, A.L. de

    1989-01-01

    A correlation was developed to estimate the maximum pressure of dry containment of PWR following a Loss-of-Coolant Accident - LOCA. The expression proposed is a function of the total energy released to the containment by the primary circuit, of the free volume of the containment building and of the total surface are of the heat-conducting structures. The results show good agreement with those present in Final Safety Analysis Report - FSAR of several PWR's plants. The errors are in the order of ± 12%. (author) [pt

  4. Adaptation of a zero-dimensional cylinder pressure model for diesel engines using the crankshaft rotational speed

    Science.gov (United States)

    Weißenborn, E.; Bossmeyer, T.; Bertram, T.

    2011-08-01

    Tighter emission regulations are driving the development of advanced engine control strategies relying on feedback information from the combustion chamber. In this context, it is especially seeked for alternatives to expensive in-cylinder pressure sensors. The present study addresses these issues by pursuing a simulation-based approach. It focuses on the extension of an empirical, zero-dimensional cylinder pressure model using the engine speed signal in order to detect cylinder-wise variations in combustion. As a special feature, only information available from the standard sensor configuration are utilized. Within the study, different methods for the model-based reconstruction of the combustion pressure including nonlinear Kalman filtering are compared. As a result, the accuracy of the cylinder pressure model can be enhanced. At the same time, the inevitable limitations of the proposed methods are outlined.

  5. Cylinder pressure, performance parameters, heat release, specific heats ratio and duration of combustion for spark ignition engine

    International Nuclear Information System (INIS)

    Shehata, M.S.

    2010-01-01

    An experimental work were conducted for investigating cylinder pressure, performance parameters, heat release, specific heat ratio and duration of combustion for multi cylinder spark ignition engine (SIE). Ccylinder pressure was measured for gasoline, kerosene and Liquefied Petroleum Gases (LPG) separately as a fuel for SIE. Fast Fourier Transformations (FFT) was used to cylinder pressure data transform from time domain into frequency domain to develop empirical correlation for calculating cylinder pressures at different engine speeds and different fuels. In addition, Inverse Fast Fourier Transformations (IFFT) was used to cylinder pressure reconstruct into time domain. The results gave good agreement between the measured cylinder pressure and the reconstructed cylinder pressure in time domain with different engine speeds and different fuels. The measured cylinder pressure and hydraulic dynamotor were the sours of data for calculating engine performance parameters. First law of thermodynamics and single zone heat release model with temperature dependant specific heat ratio γ(T) were the main tools for calculating heat release and heat transfer to cylinder walls. Third order empirical correlation for calculating γ(T) was one of the main gains of the present study. The correlation gave good agreement with other researchers with wide temperatures range. For kerosene, cylinder pressure is higher than for gasoline and LPG due to high volumetric efficiency where kerosene density (mass/volume ratio) is higher than gasoline and LPG. In addition, kerosene heating value is higher than gasoline that contributes in heat release rate and pressure increases. Duration of combustion for different engine speeds was determined using four different methods: (I) Mass fuel burnt, (II) Entropy change, (III) Temperature dependant specific heat ratio γ(T), and (IV) Logarithmic scale of (P and V). The duration of combustion for kerosene is smaller than for gasoline and LPG due to high

  6. Cylinder pressure, performance parameters, heat release, specific heats ratio and duration of combustion for spark ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Shehata, M.S. [Mechanical Engineering Technology Department, Higher Institute of Technology, Banha University, 4Zagalol Street, Benha, Galubia 1235 Z (Egypt)

    2010-12-15

    An experimental work were conducted for investigating cylinder pressure, performance parameters, heat release, specific heat ratio and duration of combustion for multi cylinder spark ignition engine (SIE). Ccylinder pressure was measured for gasoline, kerosene and Liquefied Petroleum Gases (LPG) separately as a fuel for SIE. Fast Fourier Transformations (FFT) was used to cylinder pressure data transform from time domain into frequency domain to develop empirical correlation for calculating cylinder pressures at different engine speeds and different fuels. In addition, Inverse Fast Fourier Transformations (IFFT) was used to cylinder pressure reconstruct into time domain. The results gave good agreement between the measured cylinder pressure and the reconstructed cylinder pressure in time domain with different engine speeds and different fuels. The measured cylinder pressure and hydraulic dynamotor were the source of data for calculating engine performance parameters. First law of thermodynamics and single zone heat release model with temperature dependant specific heat ratio {gamma}(T) were the main tools for calculating heat release and heat transfer to cylinder walls. Third order empirical correlation for calculating {gamma}(T) was one of the main gains of the present study. The correlation gave good agreement with other researchers with wide temperatures range. For kerosene, cylinder pressure is higher than for gasoline and LPG due to high volumetric efficiency where kerosene density (mass/volume ratio) is higher than gasoline and LPG. In addition, kerosene heating value is higher than gasoline that contributes in heat release rate and pressure increases. Duration of combustion for different engine speeds was determined using four different methods: (I) Mass fuel burnt, (II) Entropy change, (III) Temperature dependant specific heat ratio {gamma}(T), and (IV) Logarithmic scale of (P and V). The duration of combustion for kerosene is smaller than for gasoline and

  7. Further studies on stress intensity factors of semi-elliptical cracks in pressurized cylinders

    International Nuclear Information System (INIS)

    Kobayashi, A.S.; Emery, A.F.; Love, W.J.; Jain, A.

    1979-01-01

    The authors have used, in the past, the three-dimensional stress intensity magnification factor, Msub(KS), for a semi-elliptical surface crack in a flat plate with a curvature correction factor, Msub(C), to estimate the stress intensity magnification factor, Msub(K) = Msub(C) x Msub(KS), for unpressurized and pressurized inner semi-elliptical cracks and unpressurized outer semi-elliptical cracks in pressurized and thermally shocked cylinders. Recent papers by Atluri/Kathiresan, Welliot/Labbens/Pellissier-Tanon and McGowan/Raymund, however, showed that while this plate analogy with curvature correction provided reasonable estimates of the stress intensity factors at the deepest crack penetration, it underestimated the stress intensity factors at the cylindrical surface. The source of this discrepancy was traced to the curvature correction factor Msub(C), which was re-evaluated for various crack configurations and cylindrical geometries studied. Using the updated Msub(C) together with the previously derived Msub(KS), stress intensity factor magnification factor, Msub(K), was rederived for: (1) Pressurized and unpressurized inner semi-elliptical cracks of two crack aspects ratios of b/a = 0.2 and 0.98 at crack depth of b/(Rsub(o)-Rsub(i)) = 0.4, 0.6, and 0.8 in pressurized cylinders with outside-to-inside radius ratios of Rsub(o)/Rsub(i) = 3/2, 5/4, 7/6, and 10/9. (2) Unpressurized outer semi-elliptical cracks of two crack aspect ratios of b/a = 0.2 and 0.98 at crack depths of b/(Rsub(o)-Rsub(i)) = 0.4, 0.6, and 0.8 in pressurized cylinders with outside-to-inside radius ratio of Rsub(o)/Rsub(i) = 3/2, 5/4, 7/6, and 10/9. (orig.)

  8. Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

    Directory of Open Access Journals (Sweden)

    Mi Guofa

    2008-05-01

    Full Text Available Shrinkage defects can be formed easily at Critical location during low pressure die casting (LPDC of aluminum alloy cylinder body. It has harmful effect on the products. Mold fi lling and solidifi cation process of a cylinder body was simulated by using of Z-CAST software. The casting method was improved based on the simulation results. In order to create effective feeding passage, the structure of casting was modifi ed by changing the location of strengthening ribs at the bottom, without causing any adverse effect on the part’s performance. Inserting copper billet at suitable location of the die is a valid way to create suitable solidifi cation sequence that is benefi cial to the feeding. Using these methods, the shrinkage defect was completely eliminated at the critical location.

  9. IN-CYLINDER MASS FLOW ESTIMATION AND MANIFOLD PRESSURE DYNAMICS FOR STATE PREDICTION IN SI ENGINES

    Directory of Open Access Journals (Sweden)

    Wojnar Sławomir

    2014-06-01

    Full Text Available The aim of this paper is to present a simple model of the intake manifold dynamics of a spark ignition (SI engine and its possible application for estimation and control purposes. We focus on pressure dynamics, which may be regarded as the foundation for estimating future states and for designing model predictive control strategies suitable for maintaining the desired air fuel ratio (AFR. The flow rate measured at the inlet of the intake manifold and the in-cylinder flow estimation are considered as parts of the proposed model. In-cylinder flow estimation is crucial for engine control, where an accurate amount of aspired air forms the basis for computing the manipulated variables. The solutions presented here are based on the mean value engine model (MVEM approach, using the speed-density method. The proposed in-cylinder flow estimation method is compared to measured values in an experimental setting, while one-step-ahead prediction is illustrated using simulation results.

  10. The plastic work required to induce the limit pressure of a plain cylinder

    International Nuclear Information System (INIS)

    Lee, K.S.; Moreton, D.N.; Moffat, D.G.

    2005-01-01

    There has recently been a revival of interest in the definition of the limit and plastic loads of a structure, particularly piping components. Recent proposals have suggested definitions based upon plastic work. In order to normalise such quantities, the plastic work associated with the limit pressure of a plain cylinder may be required. Whilst no unique value for this quantity can be obtained through analysis, this article demonstrates that classical methods allow solutions to be obtained through an empirical route and through an analysis using several approximations. This latter analysis is shown to be adequate for the applications envisaged here

  11. Analytical Investigation of Elastic Thin-Walled Cylinder and Truncated Cone Shell Intersection Under Internal Pressure.

    Science.gov (United States)

    Zamani, J; Soltani, B; Aghaei, M

    2014-10-01

    An elastic solution of cylinder-truncated cone shell intersection under internal pressure is presented. The edge solution theory that has been used in this study takes bending moments and shearing forces into account in the thin-walled shell of revolution element. The general solution of the cone equations is based on power series method. The effect of cone apex angle on the stress distribution in conical and cylindrical parts of structure is investigated. In addition, the effect of the intersection and boundary locations on the circumferential and longitudinal stresses is evaluated and it is shown that how quantitatively they are essential.

  12. Radiation pressure acceleration: The factors limiting maximum attainable ion energy

    Energy Technology Data Exchange (ETDEWEB)

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bulanov, S. V. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); A. M. Prokhorov Institute of General Physics RAS, Moscow 119991 (Russian Federation); Esirkepov, T. Zh.; Kando, M. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); Pegoraro, F. [Physics Department, University of Pisa and Istituto Nazionale di Ottica, CNR, Pisa 56127 (Italy); Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States)

    2016-05-15

    Radiation pressure acceleration (RPA) is a highly efficient mechanism of laser-driven ion acceleration, with near complete transfer of the laser energy to the ions in the relativistic regime. However, there is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. The tightly focused laser pulses have group velocities smaller than the vacuum light speed, and, since they offer the high intensity needed for the RPA regime, it is plausible that group velocity effects would manifest themselves in the experiments involving tightly focused pulses and thin foils. However, in this case, finite spot size effects are important, and another limiting factor, the transverse expansion of the target, may dominate over the group velocity effect. As the laser pulse diffracts after passing the focus, the target expands accordingly due to the transverse intensity profile of the laser. Due to this expansion, the areal density of the target decreases, making it transparent for radiation and effectively terminating the acceleration. The off-normal incidence of the laser on the target, due either to the experimental setup, or to the deformation of the target, will also lead to establishing a limit on maximum ion energy.

  13. Cylinder pressure sensing and model-based control in engine management systems

    Energy Technology Data Exchange (ETDEWEB)

    Truscott, A.; Noble, A.; Akoachere, A.; Beaumont, A. [Ricardo Consulting Engineers Ltd., Bridge Works (United Kingdom); Mueller, R.; Hart, M. [FT2/EA, HPC T721, DaimlerChrysler AG, Stuttgart (Germany); Kroetz, G. [FT2/M, DaimlerChrysler AG, Muenchen (Germany); Cavalloni, C.; Gnielka, M. [Kistler Instrumente AG, Winterthur (Switzerland)

    2000-07-01

    Global demands on fuel economy and lower emissions from automotive vehicles have had a large impact on the development of engine management systems (EMS) in recent years. However, despite the advances in system hardware, the software programmed into these systems has yet to utilise the full potential of modern control methodologies. Model based control and diagnostics is the next step forward in the development of EMS software with the potential of providing improvements in cost, efficiency, emissions and comfort. However, the full utilisation of such techniques requires very close monitoring of engine conditions. This is made possible with the advent of new inexpensive sensor technology that can withstand the harsh environment of the combustion chamber. To exploit the above advances, the AENEAS collaborative project is being carried out by Ricardo, DaimlerChrysler and Kistler, with financial support from the European Commission and Swiss government, and has the objective of realising the benefits of cylinder pressure based engine management system (CPEMS) technology. This paper describes the application of CPEMS technology to a spark ignition (SI) engine. It describes how the combination of model based algorithms, incorporating physical principles, and cylinder pressure sensing can provide an effective means of engine control and diagnostics. (orig.)

  14. Effect of Diesel Engine Converted to Sequential Port Injection Compressed Natural Gas Engine on the Cylinder Pressure vs Crank Angle in Variation Engine Speeds

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is b...

  15. Effect of Material Parameters on Steady State Creep in a Thick Composite Cylinder Subjected to Internal Pressure

    Directory of Open Access Journals (Sweden)

    Tejeet Singh

    2009-12-01

    Full Text Available The steady state creep in Al- SiCP composite cylinder subjected to internal pressure was investigated. The creep behavior of the material were described by threshold stress based creep law by assuming a stress exponent of 5. The effect of size and content of the reinforcement (SiCP , and operating temperature on the stresses and strain rates in the composite cylinder were investigated. The stresses in the cylinder did not have significant variation with varying size and content of the reinforcement, and operating temperature. However, the tangential as well as radial strain rates in the cylinder could be reduced to a significant extent by decreasing size of SiCP, increasing the content of SiCP and decreasing operating temperature.

  16. A low-background piston-cylinder-type hybrid high pressure cell for muon-spin rotation/relaxation experiments

    Science.gov (United States)

    Shermadini, Z.; Khasanov, R.; Elender, M.; Simutis, G.; Guguchia, Z.; Kamenev, K. V.; Amato, A.

    2017-10-01

    A low background double-wall piston-cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERYLCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (μSR) measurements. The mechanical design and performance of the pressure cell are evaluated using finite-element analysis (FEA). By including the measured stress-strain characteristics of the materials into the finite-element model, the cell dimensions are optimized with the aim to reach the highest possible pressure while maintaining the sample space large (6 mm in diameter and 12 mm high). The presented unconventional design of the double-wall piston-cylinder pressure cell with a harder outer MP35N sleeve and a softer inner CuBe cylinder enables pressures of up to 2.6 GPa to be reached at ambient temperature, corresponding to 2.2 GPa at low temperatures without any irreversible damage to the pressure cell. The nature of the muon stopping distribution, mainly in the sample and in the CuBe cylinder, results in a low-background μSR signal.

  17. Interferometric fiber-optic sensor embedded in a spark plug for in-cylinder pressure measurement in engines.

    Science.gov (United States)

    Bae, Taehan; Atkins, Robert A; Taylor, Henry F; Gibler, William N

    2003-02-20

    Pressure sensing in an internal combustion engine with an intrinsic fiber Fabry-Perot interferometer (FFPI) integrated with a spark plug is demonstrated for the first time. The spark plug was used for the ignition of the cylinder in which it was mounted. The FFPI element, protected with a copper/gold coating, was embedded in a groove in the spark-plug housing. Gas pressure inthe engine induced longitudinal strain in this housing, which was also experienced by the fiber-optic sensing element. The sensor was monitored with a signal conditioning unit containing a chirped distributed-feedback laser. Pressure sensitivities as high as 0.00339 radians round-trip phase shift per pounds per square inch of pressure were observed. Measured pressure versus time traces showed good agreement with those from a piezoelectric reference sensor mounted in the same engine cylinder.

  18. Maximum respiratory pressure measuring system : calibration and evaluation of uncertainty

    NARCIS (Netherlands)

    Ferreira, J.L.; Pereira, N.C.; Oliveira Júnior, M.; Vasconcelos, F.H.; Parreira, V.F.; Tierra-Criollo, C.J.

    2010-01-01

    The objective of this paper is to present a methodology for the evaluation of uncertainties in the measurements results obtained during the calibration of a digital manovacuometer prototype (DM) with a load cell sensor pressure device incorporated. Calibration curves were obtained for both pressure

  19. 77 FR 27079 - High Pressure Steel Cylinders From China Notice of Commission Determination To Conduct a Portion...

    Science.gov (United States)

    2012-05-08

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-480 and 731-TA-1188 (Final)] High Pressure Steel Cylinders From China Notice of Commission Determination To Conduct a Portion of the Hearing... Commission Rule 201.39 (19 CFR 201.39) that, in his opinion, a portion of the Commission's hearing in High...

  20. Relation between the Fluctuating Wall Pressure and the Turbulent Structure of a Boundary Layer on a Cylinder in Axial Flow

    Science.gov (United States)

    1993-08-12

    Rlain in . power spectral density of the fluctuating wall pressure on the cylinder, boldine . fractional contribution to the total wall pressure energy...or repeated sequences of events are responsible for the production of turbulence in the near- wall region and the desire to extract their...signals over a prespecified window centered about the event detection times to extract the individual events. I 3.) Ensemble average the individual

  1. Multidimensional modeling of the effect of fuel injection pressure on temperature distribution in cylinder of a turbocharged DI diesel engine

    Directory of Open Access Journals (Sweden)

    Sajjad Emami

    2013-06-01

    Full Text Available In this study, maintaining a constant fuel rate, injection pressure of 275 bar to 1000 bar (275×102 kPa to 1000×102 kPa, has been changed. Effect of injection pressure, the pressure inside the cylinder on the free energy, power, engine indicators, particularly indicators of fuel consumption, pollutants and their effects on parameters affecting the output of the engine combustion chamber have been studied in droplet diameter. Finally, the effects of fuel mixture equivalence, Cantor temperature, soot and NOx due to the increase of injection pressure, engine efficiency and emissions have been examined.

  2. Ultimate strength analysis of ring-stiffened cylinders subjected to hydrostatic pressure

    International Nuclear Information System (INIS)

    Park, Chi Mo

    1990-01-01

    In this study, ultimate strength analysis of ring-stiffened cylinders have been performed, considering the elasto-plastic large deflection. In the elasto-plastic analysis, von Mises yield criteria, the plastic flow theory and the layered approach have been adopted. In order to take into account the follower force effect of the hydrostatic pressure, the incremental load components have been updated at every loading step. As collapse modes, axisymmetric yielding, interframe shell buckling and general buckling are considered, while local buckling of ring-stiffener is not considered. Initial shape imperfection is assumed to be the elastic buckling mode to obtain the lower bound of the ultimate strength. Results of numerical analysis are compared with the experimental results to show the validity of the present approach. It has been drawn that the present numerical results are closely correlated with the experimental results. On the other hand, the effects of initial shape imperfection and condition on the ultimate strength have been investigated. (Author)

  3. Self adaptive internal combustion engine control for hydrogen mixtures using piezoelectric transducers for dynamic cylinder pressure monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Courteau, R.; Bose, T.K. [Quebec Univ., Trois-Rivieres, PQ (Canada). Institut de recherche sur l' hydrogene

    2004-07-01

    Hydrogen internal combustion engine research at the Hydrogen Research Institute includes the following infrastructure: a 20 square metre test cell, an engine preparation room, a 150 hp dynamometer, exhaust gas analysers and a hydrogen supply. The goal of the research is to develop internal combustion engine technologies that can use hydrogen as a fuel without knocking, backfires, excessive engine wear, and with low emissions. As well as hydrogen, fuels such as biogas are also investigated. Technologies under investigation include adaptive control algorithms, as well as advanced sensors and actuators. The latter include piezolelectrics, optical fibres, nitrogen oxide detectors, and chemical composition detectors. Developments include microprocessor-controlled injection and ignition control systems for both single cylinder and multicylinder engines. Research on the influence of fuel composition on best ignition timing is presented. There is also dynamic cylinder pressure monitoring to prevent knocking make engine state assessments and perform engine calibration. Piezoelectric cylinder pressure sensors are employed, either integrated with the spark plugs, or stand-alone, inserted through separate holes through the cylinder head. tabs, figs.

  4. 49 CFR 192.619 - Maximum allowable operating pressure: Steel or plastic pipelines.

    Science.gov (United States)

    2010-10-01

    ... plastic pipelines. 192.619 Section 192.619 Transportation Other Regulations Relating to Transportation... Operations § 192.619 Maximum allowable operating pressure: Steel or plastic pipelines. (a) No person may operate a segment of steel or plastic pipeline at a pressure that exceeds a maximum allowable operating...

  5. Effect of injection pressure on performance, emission, and combustion characteristics of diesel-acetylene-fuelled single cylinder stationary CI engine.

    Science.gov (United States)

    Srivastava, Anmesh Kumar; Soni, Shyam Lal; Sharma, Dilip; Jain, Narayan Lal

    2018-03-01

    In this paper, the effect of injection pressure on the performance, emission, and combustion characteristics of a diesel-acetylene fuelled single cylinder, four-stroke, direct injection (DI) diesel engine with a rated power of 3.5 kW at a rated speed of 1500 rpm was studied. Experiments were performed in dual-fuel mode at four different injection pressures of 180, 190, 200, and 210 bar with a flow rate of 120 LPH of acetylene and results were compared with that of baseline diesel operation. Experimental results showed that highest brake thermal efficiency of 27.57% was achieved at injection pressure of 200 bar for diesel-acetylene dual-fuel mode which was much higher than 23.32% obtained for baseline diesel. Carbon monoxide, hydrocarbon, and smoke emissions were also measured and found to be lower, while the NO x emissions were higher at 200 bar in dual fuel mode as compared to those in other injection pressures in dual fuel mode and also for baseline diesel mode. Peak cylinder pressure, net heat release rate, and rate of pressure rise were also calculated and were higher at 200 bar injection pressure in dual fuel mode.

  6. A low-background piston-cylinder type hybrid high pressure cell for muon-spin rotation/relaxation experiments

    OpenAIRE

    Shermadini, Z.; Khasanov, R.; Elender, M.; Simutis, G.; Guguchia, Z.; Kamenev, K. V.; Amato, A.

    2017-01-01

    A low background double-wall piston-cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERLYCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (muSR) measurements. The mechanical design and performance of the pressure cell are evaluated using finite-element analysis (FEA). By including the measured stress-strain characteristics of the material into the ...

  7. Analyses on interaction of internal and external surface cracks in a pressurized cylinder by hybrid boundary element method

    International Nuclear Information System (INIS)

    Chai Guozhong; Fang Zhimin; Jiang Xianfeng; Li Gan

    2004-01-01

    This paper presents a comprehensive range of analyses on the interaction of two identical semi-elliptical surface cracks at the internal and external surfaces of a pressurized cylinder. The considered ratios of the crack depth to crack length are b/a=0.25, 0.5, 0.75 and 1.0; the ratios of the crack depth to wall thickness of the cylinder are 2b/t=0.2, 0.4, 0.6, 0.7 and 0.8. Forty crack configurations are analyzed and the stress intensity factors along the crack front are presented. The numerical results show that for 2b/t<0.7, the interaction leads to a decrease in the stress intensity factors for both internal and external surface cracks, compared with a single internal or external surface crack. Thus for fracture analysis of a practical pressurized cylinder with two identical semi-elliptical surface cracks at its internal and external surfaces, a conservative result is obtained by ignoring the interaction

  8. Comparing in Cylinder Pressure Modelling of a DI Diesel Engine Fuelled on Alternative Fuel Using Two Tabulated Chemistry Approaches.

    Science.gov (United States)

    Ngayihi Abbe, Claude Valery; Nzengwa, Robert; Danwe, Raidandi

    2014-01-01

    The present work presents the comparative simulation of a diesel engine fuelled on diesel fuel and biodiesel fuel. Two models, based on tabulated chemistry, were implemented for the simulation purpose and results were compared with experimental data obtained from a single cylinder diesel engine. The first model is a single zone model based on the Krieger and Bormann combustion model while the second model is a two-zone model based on Olikara and Bormann combustion model. It was shown that both models can predict well the engine's in-cylinder pressure as well as its overall performances. The second model showed a better accuracy than the first, while the first model was easier to implement and faster to compute. It was found that the first method was better suited for real time engine control and monitoring while the second one was better suited for engine design and emission prediction.

  9. Pressure transmission area and maximum pressure transmission of different thermoplastic resin denture base materials under impact load.

    Science.gov (United States)

    Nasution, Hubban; Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu

    2018-01-01

    The purposes of the present study were to examine the pressure transmission area and maximum pressure transmission of thermoplastic resin denture base materials under an impact load, and to evaluate the modulus of elasticity and nanohardness of thermoplastic resin denture base. Three injection-molded thermoplastic resin denture base materials [polycarbonate (Basis PC), ethylene propylene (Duraflex), and polyamide (Valplast)] and one conventional heat-polymerized acrylic resin (PMMA, SR Triplex Hot) denture base, all with a mandibular first molar acrylic resin denture tooth set in were evaluated (n=6). Pressure transmission area and maximum pressure transmission of the specimens under an impact load were observed by using pressure-sensitive sheets. The modulus of elasticity and nanohardness of each denture base (n=10) were measured on 15×15×15×3mm 3 specimen by using an ultramicroindentation system. The pressure transmission area, modulus of elasticity, and nanohardness data were statistically analyzed with 1-way ANOVA, followed by Tamhane or Tukey HSD post hoc test (α=.05). The maximum pressure transmission data were statistically analyzed with Kruskal-Wallis H test, followed by Mann-Whitney U test (α=.05). Polymethyl methacrylate showed significantly larger pressure transmission area and higher maximum pressure transmission than the other groups (Pelasticity and nanohardness among the four types of denture bases (Pelasticity and nanohardness of each type of denture base were demonstrated. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  10. The role of pressure anisotropy on the maximum mass of cold ...

    Indian Academy of Sciences (India)

    ,. Pune 411 007, India. 3 ... red-shift and mass increase in the presence of anisotropic pressures; numerical values are generated which are in ... that anisotropy may also change the limiting values of the maximum mass of com- pact stars.

  11. Advanced closed loop combustion control of a LTC diesel engine based on in-cylinder pressure signals

    International Nuclear Information System (INIS)

    Carlucci, A.P.; Laforgia, D.; Motz, S.; Saracino, R.; Wenzel, S.P.

    2014-01-01

    Highlights: • We have proposed an in-cylinder pressure-based closed loop combustion control. • We have tested the control on an engine at the test bench. • We have tested the control on the engine equipping a Euro 6-compliant vehicle. • The control is effective in increasing torque stability and reduce engine noise. - Abstract: The adoption of diesel LTC combustion concepts is widely recognised as a practical way to reduce simultaneously nitric oxides and particulate emission levels from diesel internal combustion engines. However, several challenges have to be faced up when implementing diesel LTC concepts in real application vehicles. In particular, achieving acceptable performance concerning the drivability comfort, in terms of output torque stability and combustion noise during engine dynamic transients, is generally a critical point. One of the most promising solutions to improve the LTC combustion operation lays in the exploitation of closed loop combustion control, based on in-cylinder pressure signals. In this work, the application of an in-cylinder pressure-based closed loop combustion control to a Euro 6-compliant demonstrator vehicle has been developed. The main challenges deriving from the control of the LTC combustion, directly affecting the engine/vehicle performance, have been analysed in detail. In order to overcome these drawbacks, a new control function, integrated into the base closed loop system, has been designed. The performance of the new function have been experimentally tested at the engine test bench. Results showed a significant enhancement of the LTC operation, in terms of both combustion stability and noise reduction during engine transients. The new function was also implemented on a real vehicle, thus proving the potential of the new control concept in realistic operating conditions

  12. Stresses in reinforced nozzle-cylinder attachments under internal pressure loading analyzed by the finite-element method: a parameter study

    International Nuclear Information System (INIS)

    Bryson, J.W.; Johnson, W.G.; Bass, B.R.

    1977-01-01

    A parameter study was conducted on stresses in reinforced nozzle-to-cylinder attachments under internal pressure loading as analyzed by the finite-element method. Twenty-five models with branch-to-run diameter ratios 0.08 less than or equal to d/D less than or equal to 0.50 and run diameter-to-thickness ratios 10 less than or equal to D/T less than or equal to 100 were investigated. A three-dimensional finite-element program, CORTES-SA, which was developed at the University of California at Berkeley specifically for analyzing tee-joint configurations, was used in the study. It was concluded from the study that both of the reinforcement designs investigated significantly reduce maximum stresses relative to configurations having little or no reinforcement. For internal pressure loading, neither of the reinforcement designs offered a significant advantage over the other in that both types of reinforcement gave very nearly the same maximum stresses

  13. Delamination of Composite Cylinders

    Science.gov (United States)

    Davies, Peter; Carlsson, Leif A.

    The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the delamination fracture resistance increases with increasing winding angle and mode II (shear) fraction (GΠ/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamina-tion damage on the strength of the cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure. The response of glass/epoxy cylinders was compared to impacted carbon reinforced cylinders. Carbon/epoxy is more sensitive to damage but retains higher implosion resistance while carbon/PEEK shows the opposite trend.

  14. In-cylinder pressure-based direct techniques and time frequency analysis for combustion diagnostics in IC engines

    International Nuclear Information System (INIS)

    D’Ambrosio, S.; Ferrari, A.; Galleani, L.

    2015-01-01

    Highlights: • Direct pressure-based techniques have been applied successfully to spark-ignition engines. • The burned mass fraction of pressure-based techniques has been compared with that of 2- and 3-zone combustion models. • The time frequency analysis has been employed to simulate complex diesel combustion events. - Abstract: In-cylinder pressure measurement and analysis has historically been a key tool for off-line combustion diagnosis in internal combustion engines, but online applications for real-time condition monitoring and combustion management have recently become popular. The present investigation presents and compares different low computing-cost in-cylinder pressure based methods for the analyses of the main features of combustion, that is, the start of combustion, the end of combustion and the crankshaft angle that responds to half of the overall burned mass. The instantaneous pressure in the combustion chamber has been used as an input datum for the described analytical procedures and it has been measured by means of a standard piezoelectric transducer. Traditional pressure-based techniques have been shown to be able to predict the burned mass fraction time history more accurately in spark ignition engines than in diesel engines. The most suitable pressure-based techniques for both spark ignition and compression ignition engines have been chosen on the basis of the available experimental data. Time–frequency analysis has also been applied to the analysis of diesel combustion, which is richer in events than spark ignited combustion. Time frequency algorithms for the calculation of the mean instantaneous frequency are computationally efficient, allow the main events of the diesel combustion to be identified and provide the greatest benefits in the presence of multiple injection events. These algorithms can be optimized and applied to onboard diagnostics tools designed for real control, but can also be used as an advanced validation tool for

  15. Development of an optical time-resolved measurement system under high-pressure and low-temperature with a piston-cylinder pressure cell

    Science.gov (United States)

    Tsuchiya, Satoshi; Kino, Yohei; Nakagawa, Koichi; Nakagawa, Daisuke; Yamada, Jun-ichi; Toda, Yasunori

    2016-04-01

    To perform the femtosecond pump-probe spectroscopy under high pressure and low temperature, we constructed a measurement system with a piston cylinder type pressure cell installing an optical fiber bundle. The applied pressure was achieved to 6 kbar and the cell was cooled down to 15 K. Several demonstrations revealed that broadening and change of polarization of pulse (duration of ˜120 fs) owing to the dispersions in the fiber bundle are much small indicating that those have little influence on the measurement of carrier relaxation dynamics. In the measurements of κ-(BEDT-TTF)2Cu(NCS)2 under 1.3 kbar at 43 K, we have successfully detected the polarization anisotropy of the carrier relaxation dynamics and estimated the decay time in the same way as the normal measurement.

  16. Experimental analysis of the structure attenuation characteristics on engine noise by pseudo cylinder pressure excitation; Giji tonaiatsu kashin ni yoru engine kozo no soon tokusei hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, H; Nakada, T [Isuzu Advanced Engineering Center, Tokyo (Japan)

    1997-10-01

    The engine structure attenuation has been experimentally analyzed by the newly developed in-cylinder excitation system. It can reproduce the complete cylinder pressure in non-running engine conditions by adopting the hydraulic and the piezoelectric actuator. The structure attenuation measured in this system has a good coincidence with the ones measured in actually engine operating conditions, meanwhile the current method, which applied only high frequency components as the excitation pressure, was shown to have the unsatisfied agreement. As a result, the proposed system has been concluded to be very useful to estimate the engine noise characteristics in non-running conditions. 4 refs., 11 figs., 1 tab.

  17. Calculation of radiation losses in cylinder symmetric high pressure discharges by means of a digital computer

    International Nuclear Information System (INIS)

    Andriessen, F.J.; Boerman, W.; Holtz, I.F.E.M.

    1973-08-01

    Computer calculations have been made of radiative energy losses in a cylindrically symmetric high pressure discharge. The calculations show that the radiation losses which occur in discharges at pressures of a few atmospheres and central temperatures of about 20000degK when compared with the electrical energy supplied, are only of importance in the neighbourhood of the centre of discharge

  18. Engine Cylinder Temperature Control

    Science.gov (United States)

    Kilkenny, Jonathan Patrick; Duffy, Kevin Patrick

    2005-09-27

    A method and apparatus for controlling a temperature in a combustion cylinder in an internal combustion engine. The cylinder is fluidly connected to an intake manifold and an exhaust manifold. The method and apparatus includes increasing a back pressure associated with the exhaust manifold to a level sufficient to maintain a desired quantity of residual exhaust gas in the cylinder, and varying operation of an intake valve located between the intake manifold and the cylinder to an open duration sufficient to maintain a desired quantity of fresh air from the intake manifold to the cylinder, wherein controlling the quantities of residual exhaust gas and fresh air are performed to maintain the temperature in the cylinder at a desired level.

  19. Critical Assessment of the Surface Tension determined by the Maximum Pressure Bubble Method

    OpenAIRE

    Benedetto, Franco Emmanuel; Zolotucho, Hector; Prado, Miguel Oscar

    2015-01-01

    The main factors that influence the value of surface tension of a liquid measured with the Maximum Pressure Bubble Method are critically evaluated. We present experimental results showing the effect of capillary diameter, capillary depth, bubble spheroidicity and liquid density at room temperature. We show that the decrease of bubble spheroidicity due to increase of capillary immersion depth is not sufficient to explain the deviations found in the measured surface tension values. Thus, we pro...

  20. Estimation of the in-cylinder air/fuel ratio of an internal combustion engine by the use of pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Tunestaal, Per

    2000-03-01

    This thesis investigates the use of cylinder pressure measurements for estimation of the in-cylinder air/fuel ratio in a spark ignited internal combustion engine. An estimation model which uses the net heat release profile for estimating the cylinder air/fuel ratio of a spark ignition engine is developed. The net heat release profile is computed from the cylinder pressure trace and quantifies the conversion of chemical energy of the reactants in the charge into thermal energy. The net heat release profile does not take heat- or mass transfer into account. Cycle-averaged air/fuel ratio estimates over a range of engine speeds and loads show an RMS error of 4.1% compared to measurements in the exhaust. A thermochemical model of the combustion process in an internal combustion engine is developed. It uses a simple chemical combustion reaction, polynominal fits of internal energy as function of temperature, and the first law of thermodynamics to derive a relationship between measured cylinder pressure and the progress of the combustion process. Simplifying assumptions are made to arrive at an equation which relates the net heat release to the cylinder pressure. Two methods for estimating the sensor offset of a cylinder pressure transducer are developed. Both methods fit the pressure data during the pre-combustion phase of the compression stroke to a polytropic curve. The first method assumes a known polytropic exponent, and the other estimates the polytropic exponent. The first method results in a linear least-squares problem, and the second method results in a nonlinear least-squares problem. The nonlinear least-squares problem is solved by separating out the nonlinear dependence and solving the single-variable minimization problem. For this, a finite difference Newton method is derived. Using this method, the cost of solving the nonlinear least-squares problem is only slightly higher than solving the linear least-squares problem. Both methods show good statistical

  1. Pressurizer /Auxiliary Spray Piping Stress Analysis For Determination Of Lead Shielding Maximum Allow Able Load

    International Nuclear Information System (INIS)

    Setjo, Renaningsih

    2000-01-01

    Piping stress analysis for PZR/Auxiliary Spray Lines Nuclear Power Plant AV Unit I(PWR Type) has been carried out. The purpose of this analysis is to establish a maximum allowable load that is permitted at the time of need by placing lead shielding on the piping system on class 1 pipe, Pressurizer/Auxiliary Spray Lines (PZR/Aux.) Reactor Coolant Loop 1 and 4 for NPP AV Unit one in the mode 5 and 6 during outage. This analysis is intended to reduce the maximum amount of radiation dose for the operator during ISI ( In service Inspection) period.The result shown that the maximum allowable loads for 4 inches lines for PZR/Auxiliary Spray Lines is 123 lbs/feet

  2. Fracture dynamics of a propagating crack in a pressurized ductile cylinder

    International Nuclear Information System (INIS)

    Emery, A.F.; Love, W.J.; Kobayashi, A.S.

    1977-01-01

    A suddenly-introduced axial through-crack in the wall of a pipe pressurized by hot water is allowed to propagate according to Weiss' notch-strength theory of ductile static fracture. The dynamic-fracture criterion used enabled the authors to obtain a unique comparison of the results of ductile-fracture with those of brittle-fracture in a fracturing A533B steel pipe. Since the pipe cross-sectional area is likely to increase with large flap motions under ductile tearing, a large deformation shell-finite-difference-dynamic-code which includes rotary inertia was used in this analysis. The uniaxial-stress-strain curve of A533B steel was approximated by a bilinear-stress-strain where Von-Mises yield criterion and associated flow rule were used in the elastic-plastic analysis. The fluid pressure was assumed constant and thus pipe flaps are only lightly loaded by pressure in this analysis. (Auth.)

  3. Thermoelastic analysis of non-uniform pressurized functionally graded cylinder with variable thickness using first order shear deformation theory(FSDT) and perturbation method

    Science.gov (United States)

    Khoshgoftar, M. J.; Mirzaali, M. J.; Rahimi, G. H.

    2015-11-01

    Recently application of functionally graded materials(FGMs) have attracted a great deal of interest. These materials are composed of various materials with different micro-structures which can vary spatially in FGMs. Such composites with varying thickness and non-uniform pressure can be used in the aerospace engineering. Therefore, analysis of such composite is of high importance in engineering problems. Thermoelastic analysis of functionally graded cylinder with variable thickness under non-uniform pressure is considered. First order shear deformation theory and total potential energy approach is applied to obtain the governing equations of non-homogeneous cylinder. Considering the inner and outer solutions, perturbation series are applied to solve the governing equations. Outer solution for out of boundaries and more sensitive variable in inner solution at the boundaries are considered. Combining of inner and outer solution for near and far points from boundaries leads to high accurate displacement field distribution. The main aim of this paper is to show the capability of matched asymptotic solution for different non-homogeneous cylinders with different shapes and different non-uniform pressures. The results can be used to design the optimum thickness of the cylinder and also some properties such as high temperature residence by applying non-homogeneous material.

  4. Fracture dynamics of a propagating crack in a pressurized ductile cylinder

    International Nuclear Information System (INIS)

    Emery, A.F.; Love, W.J.; Kobayashi, A.S.

    1977-01-01

    A suddenly-introduced axial through-crack in the wall of a pipe pressurized by hot water is allowed to propagate according to Weiss' notch-strength theory of ductile static fracture. For this somewhat ductile material of A533B steel, Weiss' criterion was extended of dynamic fracture without modification. This dynamic-fracture criterion enabled a unique comparison to be obtained for the results of ductile-fracture with those of brittle-fracture in a fracturing A533B steel pipe. Since the pipe cross-sectional area is likely to increase with large flap motions under ductile tearing, a large deformation-shell-finite-difference-dynamic-code which includes rotary inertia was used in this analysis. The uniaxial-stress-strain curve of A533B steel was approximated by a bilinear stress-strain where Von-Misses yield criterion and associated flow rule were used in the elastic-plastic analysis. The fluid pressure was assumed constant and thus pipe flaps are only lightly loaded by pressure in this analysis. In previous publications, the authors have compared their preliminary results for the shell motion obtained through their model for a fracturing pipe with those of Kanninen, et al., and Freund, et al., to evaluate the effects of pressure loading on the crack flaps and the differences between small and large deflection results. In this paper, the differences in crack-propagation behavior of a fracturing pipe composed of the same A533B but subjected to a brittle or a ductile-fracture criterion are discussed. An important conclusion in fracture dynamics derived from analyses is that a smoothly-varying crack velocity will require a non-unique crack-velocity-versus-dynamic-fracture-parameter-relation while a unique and smoothly-varying crack-velocity-versus-dynamic-fracture-parameter-relation will demand an intermittently-propagating crack

  5. A control-oriented approach to estimate the injected fuel mass on the basis of the measured in-cylinder pressure in multiple injection diesel engines

    International Nuclear Information System (INIS)

    Finesso, Roberto; Spessa, Ezio

    2015-01-01

    Highlights: • Control-oriented method to estimate injected quantities from in-cylinder pressure. • Able to calculate the injected quantities for multiple injection strategies. • Based on the inversion of a heat-release predictive model. • Low computational time demanding. - Abstract: A new control-oriented methodology has been developed to estimate the injected fuel quantities, in real-time, in multiple injection DI diesel engines on the basis of the measured in-cylinder pressure. The method is based on the inversion of a predictive combustion model that was previously developed by the authors, and that is capable of estimating the heat release rate and the in-cylinder pressure on the basis of the injection rate. The model equations have been rewritten in order to derive the injected mass as an output quantity, starting from use of the measured in-cylinder pressure as input. It has been verified that the proposed method is capable of estimating the injected mass of pilot pulses with an uncertainty of the order of ±0.15 mg/cyc, and the total injected mass with an uncertainty of the order of ±0.9 mg/cyc. The main sources of uncertainty are related to the estimation of the in-cylinder heat transfer and of the isentropic coefficient γ = c_p/c_v. The estimation of the actual injected quantities in the combustion chamber can represent a powerful means to diagnose the behavior of the injectors during engine operation, and offers the possibility of monitoring effects, such as injector ageing and injector coking, as well as of allowing an accurate control of the pilot injected quantities to be obtained; the latter are in fact usually characterized by a large dispersion, with negative consequences on the combustion quality and emission formation. The approach is characterized by a very low computational time, and is therefore suitable for control-oriented applications.

  6. Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

    Science.gov (United States)

    Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

    2006-01-03

    A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

  7. Heat release determination in a constant volume combustion chamber from the instantaneous cylinder pressure

    International Nuclear Information System (INIS)

    Lapuerta, Magín; Sanz-Argent, Josep; Raine, Robert

    2014-01-01

    A diagnostic method has been developed to interpret the results of basic combustion studies with diesel-like fuels performed in a constant volume reactor originally conceived for cetane number measurements. The main target of the method is to calculate the instantaneous heat release over time from the chamber pressure experimental signal. The method incorporates filtering of the raw data to eliminate the oscillations recorded as a consequence of the location of the pressure sensor. It considers homogeneity of the gaseous mixture (single zone model) and change in its composition due to the combustion process. A semi-empirical heat transfer model was also proposed and its coefficients were fitted from experimental results obtained in the constant volume chamber using diesel fuel. -- Highlights: • A diagnostic model for constant volume reactors has been developed and tested. • Updating the gas composition after combustion improves accuracy of the method. • Heat transfer coefficients are used for the fulfillment of boundary conditions. • The model provides a deeper insight than the apparent heat release analysis

  8. Measurement of the surface tension by the method of maximum gas bubble pressure

    International Nuclear Information System (INIS)

    Dugne, Jean

    1971-01-01

    A gas bubble method for measuring surface tension was studied. Theoretical investigations demonstrated that the maximum pressure can be represented by the envelope of a certain family of curves and that the physical nature of the capillary tube imposes an upper limit to its useful radius. With a given tube and a specified liquid, the dynamic evolution of the gas bubble depends only upon the variation of the mass of gas contained with time; this fact may restrict the choice of tubes. The use of one single tube requires important corrections. Computer treatment of the problem led to some accurate equations for calculating γ. Schroedinger equations and Sudgen's table are examined. The choice of tubes, the necessary corrections, density measurement, and the accuracy attainable are discussed. Experiments conducted with water and mercury using the sessile drop method and continuous recording of the pressure verified the theoretical ideas. (author) [fr

  9. 48 CFR 52.247-66 - Returnable Cylinders.

    Science.gov (United States)

    2010-10-01

    ... Cylinders (MAY 1994) (a) Cylinder, referred to in this clause, is a pressure vessel designed for pressures... clause. (c) For each cylinder lost or damaged beyond repair while in the Government's possession, the... associated replacement values.] These cylinders shall become Government property. (d) If any lost cylinder is...

  10. Simplified Methodology to Estimate the Maximum Liquid Helium (LHe) Cryostat Pressure from a Vacuum Jacket Failure

    Science.gov (United States)

    Ungar, Eugene K.; Richards, W. Lance

    2015-01-01

    The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared astronomical observation experiments. These experiments carry sensors cooled to liquid helium temperatures. The liquid helium supply is contained in large (i.e., 10 liters or more) vacuum-insulated dewars. Should the dewar vacuum insulation fail, the inrushing air will condense and freeze on the dewar wall, resulting in a large heat flux on the dewar's contents. The heat flux results in a rise in pressure and the actuation of the dewar pressure relief system. A previous NASA Engineering and Safety Center (NESC) assessment provided recommendations for the wall heat flux that would be expected from a loss of vacuum and detailed an appropriate method to use in calculating the maximum pressure that would occur in a loss of vacuum event. This method involved building a detailed supercritical helium compressible flow thermal/fluid model of the vent stack and exercising the model over the appropriate range of parameters. The experimenters designing science instruments for SOFIA are not experts in compressible supercritical flows and do not generally have access to the thermal/fluid modeling packages that are required to build detailed models of the vent stacks. Therefore, the SOFIA Program engaged the NESC to develop a simplified methodology to estimate the maximum pressure in a liquid helium dewar after the loss of vacuum insulation. The method would allow the university-based science instrument development teams to conservatively determine the cryostat's vent neck sizing during preliminary design of new SOFIA Science Instruments. This report details the development of the simplified method, the method itself, and the limits of its applicability. The simplified methodology provides an estimate of the dewar pressure after a loss of vacuum insulation that can be used for the initial design of the liquid helium dewar vent stacks. However, since it is not an exact

  11. Rate maximum calculation of Dpa in CNA-II pressure vessel

    International Nuclear Information System (INIS)

    Mascitti, J. A

    2012-01-01

    The maximum dpa rate was calculated for the reactor in the following state: fresh fuel, no Xenon, a Boron concentration of 15.3 ppm, critical state, its control rods in the criticality position, hot, at full power (2160 MW). It was determined that the maximum dpa rate under such conditions is 3.54(2)x10 12 s -1 and it is located in the positions corresponding to θ=210 o in the azimuthal direction, and z=20 cm and -60 cm respectively in the axial direction, considering the calculation mesh centered at half height of the fuel element (FE) active length. The dpa rate spectrum was determined as well as the contribution to it for 4 energy groups: a thermal group, two epithermal groups and a fast one. The maximum dpa rate considering the photo-neutrons production from (γ, n) reaction in the heavy water of coolant and moderator was 3.93(4)x10 12 s -1 that is 11% greater than the obtained without photo-neutrons. This verified significant difference between both cases, suggest that photo-neutrons in large heavy water reactors such as CNA-II should not be ignored. The maximum DPA rate in the first mm of the reactor pressure vessel was calculated too and it was obtained a value of 4.22(6)x10 12 s -1 . It should be added that the calculation was carried out with the reactor complete accurate model, with no approximations in spatial or energy variables. Each value has, between parentheses, a percentage relative error representing the statistical uncertainty due to the probabilistic Monte Carlo method used to estimate it. More representative values may be obtained with this method if equilibrium burn-up distribution is used (author)

  12. 700 bar hydrogen cylinder design, testing and certification

    International Nuclear Information System (INIS)

    Duncan, M.

    2004-01-01

    'Full text:' Light weight and high pressure cylinders for compressed hydrogen storage are essential components for fuel cell vehicles. Storage volume and mass are two key considerations. Current on-board hydrogen storage systems are based on a maximum pressure of 350 bar. While 350 bar systems are excellent solutions for many applications, some situations required higher storage densities due to space restrictions. As a result significant research and development work has been expended by cylinder manufacturers, systems providers, testing agencies and automotive manufacturers to develop 700 bar systems to reduce storage volume. Dynetek Industries Ltd has proactively developed a range of 700 bar storage cylinders based on a seamless aluminum liner over wrapped with a carbon fiber composite. This paper presents the challenges and processes involved in the design, testing and certification of the Dynetek Industries Ltd 700 bar cylinder. The paper also provides reasoning for further volume and mass optimization of compressed hydrogen cylinders by incorporating realistic cylinder usage parameters into standards. In particular the overly conservative fill life requirement for cylinders will be examined. (author)

  13. Dynamic surface tension measurements of ionic surfactants using maximum bubble pressure tensiometry

    Science.gov (United States)

    Ortiz, Camilla U.; Moreno, Norman; Sharma, Vivek

    Dynamic surface tension refers to the time dependent variation in surface tension, and is intimately linked with the rate of mass transfer of a surfactant from liquid sub-phase to the interface. The diffusion- or adsorption-limited kinetics of mass transfer to interfaces is said to impact the so-called foamability and the Gibbs-Marangoni elasticity of surfaces. Dynamic surface tension measurements carried out with conventional methods like pendant drop analysis, Wilhelmy plate, etc. are limited in their temporal resolution (>50 ms). In this study, we describe design and application of maximum bubble pressure tensiometry for the measurement of dynamic surface tension effects at extremely short (1-50 ms) timescales. Using experiments and theory, we discuss the overall adsorption kinetics of charged surfactants, paying special attention to the influence of added salt on dynamic surface tension.

  14. Global limit load solutions for thick-walled cylinders with circumferential cracks under combined internal pressure, axial force and bending moment − Part II: Finite element validation

    International Nuclear Information System (INIS)

    Li, Yuebing; Lei, Yuebao; Gao, Zengliang

    2014-01-01

    Global limit load solutions for thick-walled cylinders with circumferential internal/external surface and through-wall defects under combined positive/negative axial force, positive/negative global bending moment and internal pressure have been developed in Part I of this paper. In this Part II, elastic-perfectly plastic 3-D finite element (FE) analyses are performed for selected cases, covering a wide range of geometries and load combinations, to validate the developed limit load solutions. The results show that these limit load solutions can predict the FE data very well for the cases with shallow or deep and short cracks and are conservative. For the cases with very long and deep cracks, the predictions are reasonably accurate and more conservative. -- Highlights: • Elastic-perfectly plastic 3D finite element limiting analyses of cylinders. • Thin/thick-walled cylinders with circumferential surface defects. • Combined loading for pressure, end-force and global bending moment. • Totally 1458 cases analysed and tabulated normalised results provided. • Results used to validate the developed limit load solutions in Part I of this paper

  15. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Science.gov (United States)

    2010-10-01

    ... that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure piping... tests conducted in accordance with this section shall be either hydrostatic tests or pneumatic tests. (1... times the maximum allowable working pressure. (2) When a pneumatic test is conducted on a pressure...

  16. Estimation of Hydrodynamic Impact Loads and Pressure Distributions on Bodies Approximating Elliptical Cylinders with Special Reference to Water Landings of Helicopters

    Science.gov (United States)

    Schnitzer, Emanuel; Hathaway, Melvin E

    1953-01-01

    An approximate method for computing water loads and pressure distributions on lightly loaded elliptical cylinders during oblique water impacts is presented. The method is of special interest for the case of emergency water landings of helicopters. This method makes use of theory developed and checked for landing impacts of seaplanes having bottom cross sections of V and scalloped contours. An illustrative example is given to show typical results obtained from the use of the proposed method of computation. The accuracy of the approximate method was evaluated through comparison with limited experimental data for two-dimensional drops of a rigid circular cylinder at a trim of 0 degrees and a flight -path angle of 90 degrees. The applicability of the proposed formulas to the design of rigid hulls is indicated by the rough agreement obtained between the computed and experimental results. A detailed computational procedure is included as an appendix.

  17. The Influence of Pressure Distribution on the Maximum Values of Stress in FEM Analysis of Plain Bearings

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2016-12-01

    Full Text Available Several methods can be used in the FEM studies to apply the loads on a plain bearing. The paper presents a comparative analysis of maximum stress obtained for three loading scenarios: resultant force applied on the shaft – bearing assembly, variable pressure with sinusoidal distribution applied on the bearing surface, variable pressure with parabolic distribution applied on the bearing surface.

  18. Shear-induced autorotation of freely rotatable cylinder in a channel flow at moderate Reynolds number

    Science.gov (United States)

    Xia, Yi; Lin, Jianzhong; Ku, Xiaoke; Chan, Tatleung

    2018-04-01

    Flow past a center-pinned freely rotatable cylinder asymmetrically confined in a two-dimensional channel is simulated with the lattice Boltzmann method for a range of Reynolds number 0.1 ≤ Re ≤ 200, eccentricity ratio 0/8 ≤ ɛ ≤ 7/8, and blockage ratio 0.1 ≤ β ≤ 0.5. It is found that the inertia tends to facilitate the anomalous clockwise rotation of the cylinder. As the eccentricity ratio increases, the cylinder rotates faster in the counterclockwise direction and then slows down at a range of Re 40, there exists an anomalous clockwise rotation for the cylinder at a low eccentricity ratio and the domain where the cylinder rotates anomalously becomes larger with the increase in the Reynolds number. In a channel with a higher blockage ratio, the rotation of the cylinder is more sensitive to the change of cylinder lateral position, and the separatrix at which the cylinder remains a state of rest moves upward generally. The cylinder is more likely to rotate counterclockwise and the rotating velocity is larger. At a lower blockage ratio, the anomalous clockwise rotation is more likely to occur, and the largest rotating velocity occurs when the blockage ratio is equal to 0.3. The mechanism of distinct rotational behavior of the cylinder is attributed to the transformation of distribution of shear stress which is resulted from the variation of pressure drop, the shift of maximum or minimum pressure zones along the upper and lower semi-cylinder surface, and the movement of stagnant point and separate point. Finally, the effects of the cylinder rotation on the flow structure and hydrodynamic force exerted on the cylinder surface are analyzed as well.

  19. Long-term storage of compressed radioactive krypton in cylinders

    International Nuclear Information System (INIS)

    Niephaus, D.; Nommensen, O.; Bruecher, H.

    1982-01-01

    The recommendations of the German Radiation Protection Commission necessitate the separation of the radioactive noble gas krypton-85 (Kr-85) produced in large LWR reprocessing plants from the dissolver off-gas. A possible method of removal is a long-term storage of the compressed noble gas above ground in cylinders. The aim of the present study is to develop such a storage concept and evaluate its feasibility under the aspects of safety and cost. After having been filled, the gas cylinders are placed separately into transport racks serving to protect the cylinders. Following this, the cylinders are transferred out of the filling station in a transport cask, conveyed to the storage building and stored there. The storage building protects the gas cylinders against external impacts. The storage cells constitute a second barrier against the release of Kr-85. The heat produced during decay of the Kr-85 in the gas cylinders is carried off by natural convection of the air circulating in the storage cells. To study possible corrosion attack on special steels due to rubidium, experiments were conducted at 200 0 C during test periods up to 3500h. In order to compare properties at elevated temperatures, corrosion experiments were conducted at 500 0 C, which is far above the maximum licensed storage temperature of 200 0 C. Experiments were conducted concerning the adsorption of krypton on various adsorbents, thus reducing the pressure inside the gas cylinder during storage. A cost estimate based on 1980 prices

  20. [Effect of maximum blood pressure fluctuation on prognosis of patients with acute ischemic stroke within 24 hours after hospital admission].

    Science.gov (United States)

    Wang, H; Tang, Y; Zhang, Y; Xu, K; Zhao, J B

    2018-05-10

    Objective: To investigate the relationship between the maximum blood pressure fluctuation within 24 hours after admission and the prognosis at discharge. Methods: The patients with ischemic stroke admitted in Department of Neurology of the First Affiliated Hospital of Harbin Medical University within 24 hours after onset were consecutively selected from April 2016 to March 2017. The patients were grouped according to the diagnostic criteria of hypertension. Ambulatory blood pressure of the patients within 24 hours after admission were measured with bedside monitors and baseline data were collected. The patients were scored by NIHSS at discharge. The relationships between the maximum values of systolic blood pressure (SBP) or diastolic blood pressure (DBP) and the prognosis at discharge were analyzed. Results: A total of 521 patients with acute ischemic stroke were enrolled. They were divided into normal blood pressure group (82 cases) and hypertension group(439 cases). In normal blood pressure group, the maximum values of SBP and DBP were all in normal distribution ( P >0.05). The maximum value of SBP fluctuation was set at 146.6 mmHg. After adjustment for potential confounders, the OR for poor prognosis at discharge in patients with SBP fluctuation ≥146.6 mmHg was 2.669 (95 %CI : 0.594-11.992) compared with those with SBP fluctuation blood pressure at admission, the maximum values of SBP and DBP within 24 hours after admission had no relationship with prognosis at discharge. In acute ischemic stroke patients with hypertension at admission, the maximum values of SBP and DBP within 24 hours after admission were associated with poor prognosis at discharge.

  1. Periodic motions and chaos for a damped mobile piston system in a high pressure gas cylinder with P control

    International Nuclear Information System (INIS)

    Wang, Donghua; Huang, Jianzhe

    2017-01-01

    In this paper, the complex motions for a moving piston in a closed gas cylinder will be analyzed using the discrete implicit maps method. The strong nonlinearity of such system will be observed due to the large quadratic and cubic stiffness. Period-1 motions which contain high order of harmonic components will be presented. The periodic motions will be discretized into multiple continuous mappings, and such mapping can be analyzed via Newton–Raphson iteration. The stability analysis will be given and the analytic conditions for the saddle-node and period-doubling bifurcation will be determined. From the semi-analytic solution route, the possible motions without considering the impact of the piston with the end wall of the cylinder will be obtained analytically. The scheme to reduce the vibration of the piston can be obtained through the parameter studies.

  2. Mechanical solution of the maximum point of dynamic abutment pressure under deep long-wall working face

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, F.; Ma, Q. [Shandong University of Science and Technology, Tai' an (China). College of Resource and Environmental Engineering

    2002-06-01

    The paper studies the dynamic relationship between abutment pressure and overburden collapse precess with advancing of working face. The result shows that the abutment pressure reaches its maximum value when the working face dimension is 1.27 times of the mining depth. This result confirms the statistical result from the strata movement surveys that overburden reaches its full movement stage when extracting dimension reaches 1.2 1.4 times of the mining depth. 12 refs., 2 figs.

  3. Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

    Science.gov (United States)

    Ungar, Eugene K.

    2014-01-01

    The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

  4. Effect of Ovality on Maximum External Pressure of Helically Coiled Steam Generator Tubes with a Rectangular Wear

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dong In; Lim, Eun Mo; Huh, Nam Su [Seoul National Univ. of Science and Technology, Seoul (Korea, Republic of); Choi, Shin Beom; Yu, Je Yong; Kim, Ji Ho; Choi, Suhn [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    A structural integrity of steam generator tubes of nuclear power plants is one of crucial parameters for safe operation of nuclear power plants. Thus, many studies have been made to provide engineering methods to assess integrity of defective tubes of commercial nuclear power plants considering its operating environments and defect characteristics. As described above, the geometric and operating conditions of steam generator tubes in integral reactor are significantly different from those of commercial reactor. Therefore, the structural integrity assessment of defective tubes of integral reactor taking into account its own operating conditions and geometric characteristics, i. e., external pressure and helically coiled shape, should be made to demonstrate compliance with the current design criteria. Also, ovality is very specific characteristics of the helically coiled tube because it is occurred during the coiling processes. The wear, occurring from FIV (Flow Induced Vibration) and so on, is main degradation of steam generator tube. In the present study, maximum external pressure of helically coiled steam generator tube with wear is predicted based on the detailed 3-dimensional finite element analysis. As for shape of wear defect, the rectangular shape is considered. In particular, the effect of ovality on the maximum external pressure of helically coiled tubes with rectangular shaped wear is investigated. In the present work, the maximum external pressure of helically coiled steam generator tube with rectangular shaped wear is investigated via detailed 3-D FE analyses. In order to cover a practical range of geometries for defective tube, the variables affecting the maximum external pressure were systematically varied. In particular, the effect of tube ovality on the maximum external pressure is evaluated. It is expected that the present results can be used as a technical backgrounds for establishing a practical structural integrity assessment guideline of

  5. Stress analysis of cylinder to cylinder intersections

    International Nuclear Information System (INIS)

    Revesz, Z.

    1983-01-01

    Cylinder to cylinder intersections have numerous applications in the power industry from different piping junctions to pressure vessel nozzles. A specific purpose computer program has been installed at the author's establishment for finite element analysis of such geometries. Some of the experiences are presented giving a short overview of the analysis of unreinforced man-holes, demonstrating how a more economical design has been verified by analysis. The program installed has linear-elastic and elasto-plastic capabilities. Further, it is prepared for heat transfer analysis with subsequent thermal stress computation. An efficient pre- and post-processor has also been installed and enhanced by the author. The software used is at its present stage capable for problem definition with input data such as outside/ inside diameters, length and number of subdivisions. Similarly simple is the load definition and the graphic representation of the full output. (author)

  6. Study on Droplet Size and Velocity Distributions of a Pressure Swirl Atomizer Based on the Maximum Entropy Formalism

    Directory of Open Access Journals (Sweden)

    Kai Yan

    2015-01-01

    Full Text Available A predictive model for droplet size and velocity distributions of a pressure swirl atomizer has been proposed based on the maximum entropy formalism (MEF. The constraint conditions of the MEF model include the conservation laws of mass, momentum, and energy. The effects of liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio on the droplet size and velocity distributions of a pressure swirl atomizer are investigated. Results show that model based on maximum entropy formalism works well to predict droplet size and velocity distributions under different spray conditions. Liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio have different effects on droplet size and velocity distributions of a pressure swirl atomizer.

  7. 77 FR 26739 - High Pressure Steel Cylinders From the People's Republic of China: Final Determination of Sales...

    Science.gov (United States)

    2012-05-07

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... LTFV are shown in the ``Final Determination Margins'' section of this notice. \\1\\ See High Pressure... affiliated producers, Langfang Tianhai High Pressure Contain Co., Ltd. (``Langfang Tianhai''), which produced...

  8. Energy Loss, Velocity Distribution, and Temperature Distribution for a Baffled Cylinder Model, Special Report

    Science.gov (United States)

    Brevoort, Maurice J.

    1937-01-01

    In the design of a cowling a certain pressure drop across the cylinders of a radial air-cooled engine is made available. Baffles are designed to make use of this available pressure drop for cooling. The problem of cooling an air-cooled engine cylinder has been treated, for the most part, from considerations of a large heat-transfer coefficient. The knowledge of the precise cylinder characteristics that give a maximum heat-transfer coefficient should be the first consideration. The next problem is to distribute this ability to cool so that the cylinder cools uniformly. This report takes up the problem of the design of a baffle for a model cylinder. A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that the cooling can be improved 20% by using a correctly designed baffle. Such a gain is as effective in cooling the cylinder with the improved baffle as a 65% increase in pressure drop across the standard baffle and fin tips.

  9. Washing water treatment process for UF_6 cylinder by adjusting evaporation technology in a low temperature and low pressure

    International Nuclear Information System (INIS)

    Kim, Ki-tae; Ju, Young-jong; Cho, Nam-chan; Kim, Yun-kwan; Jin, Chang-suk

    2016-01-01

    The liquid waste is treated in this procedure; 1) Add NaOH to the liquid waste and filter the mixture with a screen. 2) Screened residue is dried and then stored in a uranium storage. 3) liquid part is moved to a storage tank and radioactivity is measured in the liquid. 5) If the concentration of radioactivity is lower than corresponding regulation limit, the liquid moved to a reaction tank and evaporated with additional low concentration HF in 105℃. 6) Radioactivity of distillate is measured and the value is lower than regulation, it is treated with a thermal decomposition process and discharged to the atmosphere in gas state. 7) Solid waste produced in the evaporation step is managed as solid nuclear waste. The treatment procedure mentioned above has disadvantageous points, producing large amount of solid waste as well as, high energy and chemical consumption. In this study, liquid waste from a real scaled cylinder wash process is applied to evaporation system to confirm feasibility of the application of evaporation and, to reduce waste production and energy consumption. Liquid radioactive wastewater from a real scaled UF6 cylinder wash process was applied to evaporation treatment system. Radioactive concentration in gross alpha was removed 99.9% in the evaporation system. And the concentration in distillate was lower than the discharge regulation. Removal of U-235 was 99.9% in the process. And 15 other kinds of radionuclides in the raw wastewater were removed completely. Secondary waste production of the evaporation system is 15g/L

  10. Spectroscopic diagnosis of plasma in atmospheric pressure negative pulsed gas-liquid discharge with nozzle-cylinder electrode

    Science.gov (United States)

    Ming, SUN; Zhan, TAO; Zhipeng, ZHU; Dong, WANG; Wenjun, PAN

    2018-05-01

    The plasma characteristics of a gas-liquid phase discharge reactor were investigated by optical and electrical methods. The nozzle-cylinder electrode in the discharge reactor was supplied with a negative nanosecond pulsed generator. The optical emission spectrum diagnosis revealed that OH (A2∑+ → X2Π, 306–309 nm), N2 (C3Π→B3Πg, 337 nm), O (3p5p→3s5s0, 777.2 nm) and O (3p3p→3s3s0, 844.6 nm) were produced in the discharge plasma channels. The electron temperature (T e) was calculated from the emission relative intensity ratio between the atomic O 777.2 nm and 844.6 nm, and it increased with the applied voltage and the pulsed frequency and fell within the range of 0.5–0.8 eV. The gas temperature (T g) that was measured by Lifbase was in a range from 400 K to 600 K.

  11. Social networks, leisure activities and maximum tongue pressure: cross-sectional associations in the Nagasaki Islands Study.

    Science.gov (United States)

    Nagayoshi, Mako; Higashi, Miho; Takamura, Noboru; Tamai, Mami; Koyamatsu, Jun; Yamanashi, Hirotomo; Kadota, Koichiro; Sato, Shimpei; Kawashiri, Shin-Ya; Koyama, Zenya; Saito, Toshiyuki; Maeda, Takahiro

    2017-12-06

    Social environment is often associated with health outcomes, but epidemiological evidence for its effect on oral frailty, a potential risk factor for aspiration, is sparse. This study aimed to assess the association between social environment and tongue pressure, as an important measure of oral function. The study focused on family structure, social networks both with and beyond neighbours, and participation in leisure activities. A population-based cross-sectional study. Annual health check-ups in a rural community in Japan. A total of 1982 participants, all over 40 years old. Anyone with missing data for the main outcome (n=14) was excluded. Tongue pressure was measured three times, and the maximum tongue pressure was used for analysis. A multivariable adjusted regression model was used to calculate parameter estimates (B) for tongue pressure. Having a social network involving neighbours (B=2.43, P=0.0001) and taking part in leisure activities (B=1.58, P=0.005) were independently associated with higher tongue pressure, but there was no link with social networks beyond neighbours (B=0.23, P=0.77). Sex-specific analyses showed that for men, having a partner was associated with higher tongue pressure, independent of the number of people in the household (B=2.26, P=0.01), but there was no association among women (B=-0.24, P=0.72; P-interaction=0.059). Having a social network involving neighbours and taking part in leisure activities were independently associated with higher tongue pressure. Marital status may be an important factor in higher tongue pressure in men. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Attempt of lean burn of a 4 cycle gasoline engine by the aid of low pressure air assisted in-cylinder injection; Tonai kuki nenryo funsha ni yoru lean burn no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Hatakeyama, S; Kondo, M; Sekiya, Y; Murayama, T [Hokkaido Automotive Engineering College, Hokkaido (Japan)

    1997-10-01

    Comparable performance and exhaust emission with conventional carburetor was obtained by a low Pressure air assisted in-cylinder injection system. And lean burn of idling and light load operation till A/F=70 was realized by installing a spark Plug and a reed type injection nozzle in a divided combustion chambaer of a 4 cycle gasoline engine. 2 refs., 10 figs.

  13. Maximum magnitude of injection-induced earthquakes: A criterion to assess the influence of pressure migration along faults

    Science.gov (United States)

    Norbeck, Jack H.; Horne, Roland N.

    2018-05-01

    The maximum expected earthquake magnitude is an important parameter in seismic hazard and risk analysis because of its strong influence on ground motion. In the context of injection-induced seismicity, the processes that control how large an earthquake will grow may be influenced by operational factors under engineering control as well as natural tectonic factors. Determining the relative influence of these effects on maximum magnitude will impact the design and implementation of induced seismicity management strategies. In this work, we apply a numerical model that considers the coupled interactions of fluid flow in faulted porous media and quasidynamic elasticity to investigate the earthquake nucleation, rupture, and arrest processes for cases of induced seismicity. We find that under certain conditions, earthquake ruptures are confined to a pressurized region along the fault with a length-scale that is set by injection operations. However, earthquakes are sometimes able to propagate as sustained ruptures outside of the zone that experienced a pressure perturbation. We propose a faulting criterion that depends primarily on the state of stress and the earthquake stress drop to characterize the transition between pressure-constrained and runaway rupture behavior.

  14. THE GENERALIZED MAXIMUM LIKELIHOOD METHOD APPLIED TO HIGH PRESSURE PHASE EQUILIBRIUM

    Directory of Open Access Journals (Sweden)

    Lúcio CARDOZO-FILHO

    1997-12-01

    Full Text Available The generalized maximum likelihood method was used to determine binary interaction parameters between carbon dioxide and components of orange essential oil. Vapor-liquid equilibrium was modeled with Peng-Robinson and Soave-Redlich-Kwong equations, using a methodology proposed in 1979 by Asselineau, Bogdanic and Vidal. Experimental vapor-liquid equilibrium data on binary mixtures formed with carbon dioxide and compounds usually found in orange essential oil were used to test the model. These systems were chosen to demonstrate that the maximum likelihood method produces binary interaction parameters for cubic equations of state capable of satisfactorily describing phase equilibrium, even for a binary such as ethanol/CO2. Results corroborate that the Peng-Robinson, as well as the Soave-Redlich-Kwong, equation can be used to describe phase equilibrium for the following systems: components of essential oil of orange/CO2.Foi empregado o método da máxima verossimilhança generalizado para determinação de parâmetros de interação binária entre os componentes do óleo essencial de laranja e dióxido de carbono. Foram usados dados experimentais de equilíbrio líquido-vapor de misturas binárias de dióxido de carbono e componentes do óleo essencial de laranja. O equilíbrio líquido-vapor foi modelado com as equações de Peng-Robinson e de Soave-Redlich-Kwong usando a metodologia proposta em 1979 por Asselineau, Bogdanic e Vidal. A escolha destes sistemas teve como objetivo demonstrar que o método da máxima verosimilhança produz parâmetros de interação binária, para equações cúbicas de estado capazes de descrever satisfatoriamente até mesmo o equilíbrio para o binário etanol/CO2. Os resultados comprovam que tanto a equação de Peng-Robinson quanto a de Soave-Redlich-Kwong podem ser empregadas para descrever o equilíbrio de fases para o sistemas: componentes do óleo essencial de laranja/CO2.

  15. Outcome of TVT operations in women with low maximum urethral closure pressure.

    Science.gov (United States)

    Moe, Kjartan; Schiøtz, Hjalmar A; Kulseng-Hanssen, Sigurd

    2017-06-01

    (i) To establish whether low maximal urethral closure pressure (MUCP) is associated with a poorer prognosis after TVT-surgery, and if so to establish an MUCP cut-off value for poor outcome. (ii) To characterize the population with a low MUCP. Retrospective analysis of data from 6,646 women with stress/mixed urinary incontinence included in the Norwegian Female Incontinence Registry. Postoperative subjective (degree of satisfaction), objective (leakage on stress test) and composite cure according to preoperative MUCP were analyzed in unadjusted and adjusted analysis. Preoperative variables were compared between women having a low or normal MUCP. Non-parametric tests were used on continuous variables and χ 2 tests on categorical variables. Logistic regression was used for the adjusted analysis. Level of significance: P 20 cm H 2 O. In adjusted analysis MUCP ≤20 cm H 2 O was associated with neither objective, subjective, nor composite failure. Women with MUCP TVT-surgery compared to women with MUCP >20 cm H 2 O after adjusting for preoperative variables. Neurourol. Urodynam. 36:1320-1324, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  16. Studies of the pressure dependence of the charge density distribution in cerium phosphide by the maximum-entropy method

    CERN Document Server

    Ishimatsu, N; Takata, M; Nishibori, E; Sakata, M; Hayashi, J; Shirotani, I; Shimomura, O

    2002-01-01

    The physical properties relating to 4f electrons in cerium phosphide, especially the temperature dependence and the isomorphous transition that occurs at around 10 GPa, were studied by means of x-ray powder diffraction and charge density distribution maps derived by the maximum-entropy method. The compressibility of CeP was exactly determined using a helium pressure medium and the anomaly that indicated the isomorphous transition was observed in the compressibility. We also discuss the anisotropic charge density distribution of Ce ions and its temperature dependence.

  17. Thermal characteristics during hydrogen fueling process of type IV cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Chan [Department of Fire and Disaster Prevention, Kyungil University, 33, Buhori, Hayang, Kyungsan 712-701 (Korea); Lee, Seung Hoon; Yoon, Kee Bong [Department of Mechanical Engineering, Chung Ang University, 221, Huksuk, Dongjak, Seoul 156-756 (Korea)

    2010-07-15

    Temperature increase during hydrogen fueling process is a significant safety concern of a high pressure hydrogen vessel. Hence, thermal characteristics of a Type IV cylinder during hydrogen filling process need to be understood. In this study, a series of experiments were conducted to quantify the temperature change of the cylinder during hydrogen filling to 35 MPa. Computational fluid dynamics (CFD) analysis was also conducted to simulate the conditions of the experiments. The results predicted by the CFD analysis show reasonable agreement with the experiments and the discrepancy between the CFD results and experimental results decrease with higher initial gas pressures. The upper and the lower parts of the vessel showed a temperature difference in the vertical direction. The upper gas temperature was higher than that of the lower part due to the buoyancy effect in the vessel. The maximum gas temperature was higher than the maximum temperature allowed in the ISO safety code (85 C) for the case in which the vessel was pressurized from 0 MPa to 35 MPa. This work contributes to the understanding of the thermal flow characteristics of the hydrogen filling process and notes that additional efforts should be made to guarantee the safety of a type IV cylinder during the hydrogen fueling process. (author)

  18. Hydrostatic paradox: experimental verification of pressure equilibrium

    Science.gov (United States)

    Kodejška, Č.; Ganci, S.; Říha, J.; Sedláčková, H.

    2017-11-01

    This work is focused on the experimental verification of the balance between the atmospheric pressure acting on the sheet of paper, which encloses the cylinder completely or partially filled with water from below, where the hydrostatic pressure of the water column acts against the atmospheric pressure. First of all this paper solves a theoretical analysis of the problem, which is based, firstly, on the equation for isothermal process and, secondly, on the equality of pressures inside and outside the cylinder. From the measured values the confirmation of the theoretical quadratic dependence of the air pressure inside the cylinder on the level of the liquid in the cylinder is obtained, the maximum change in the volume of air within the cylinder occurs for the height of the water column L of one half of the total height of the vessel H. The measurements were made for different diameters of the cylinder and with plates made of different materials located at the bottom of the cylinder to prevent liquid from flowing out of the cylinder. The measured values were subjected to statistical analysis, which demonstrated the validity of the zero hypothesis, i.e. that the measured values are not statistically significantly different from the theoretically calculated ones at the statistical significance level α  =  0.05.

  19. Numerical simulation coupling with experimental study on the non-uniform of each cylinder gas exchange and working processes of a multi-cylinder gasoline engine under transient conditions

    International Nuclear Information System (INIS)

    Zhou, Feng; Fu, Jianqin; Shu, Jun; Liu, Jingping; Wang, Shuqian; Feng, Renhua

    2016-01-01

    Highlights: • An approach is presented to detect the CTCV of engine under transient conditions. • The range and influence factors of CTCV of engine performances were revealed. • The maximum relative deviation of IMEP in each cylinder is larger than ±30%. • There appears a symmetry relation between CTCV of RGF and excess air coefficient. - Abstract: Cylinder-to-cylinder variation is unavoidable in multi-cylinder engine and has a severe impact on engine performance. To explore the cylinder-to-cylinder variation of engine under transient conditions, a hybrid method of dynamic signal measurement coupling with gas dynamics and thermodynamics processes simulation is presented to detect the parameters of engine. Then, this method is applied to an automobile engine under road test conditions, and the continuous state and performance parameters of each cylinder were obtained from cycle to cycle. On this basis, the range and influence factors of non-uniform of engine performance parameters were analyzed. The results show that, under transient conditions, the relative deviation of excess air coefficient in each cylinder is within ±5%, which is mainly affected by intake average pressure in low to medium speed operating regions but influenced by exhaust pressure wave and residual gas fraction in high-speed and high-load operating regions. There appears a symmetry relation between the non-uniform of RGF and excess air coefficient. The relative deviation of indicated mean effective pressure in each cylinder depends largely on the gas exchange performance, including excess air coefficient and residual gas fraction, and the maximum is larger than ±30%.

  20. The maximum and minimum values of the heat Q transmitted from metal to boiling water under atmospheric pressure

    International Nuclear Information System (INIS)

    Nukiyama, S.

    1991-01-01

    The quantity of heat transmitted from a metal surface to boiling water increases as the temperature difference ΔT is increased, but after the ΔT has reached a certain limit, quantity Q decreases with further increase in ΔT. This turning point is the maximum value of heat transmitted. The existence of this point was actually observed in the experiment. Under atmospheric pressure, ΔT corresponding to the maximum value of heat transfer for water at 100 degrees C falls between 20-40 degrees C, and Q is between 1,080,000 and 1,800,000 kcal/m 2 h (i.e. between 2,000 and 3,000 kg/m 2 h, if expressed in constant evaporation rate at 100 degrees C); this figure is larger than the maximum value of heat transfer as was previously considered. In this paper the minimum value of heat transfer was obtained, and in the Q-ΔT curve for the high temperature region, the burn-out effect is discussed

  1. Fire exposure of empty 30B cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, K.T. [MJB Technical Associates, Inc., Knoxville, TN (United States)

    1991-12-31

    Cylinders for UF{sub 6} handling, transport, and storage are designed and built as unfired pressure vessels under ASME Boiler and Pressure Vessel Code criteria and standards. They are normally filled and emptied while UF{sub 6} is in its liquid phase. Transport cylinders such as the Model 30B are designed for service at 200 psi and 250{degrees}F, to sustain the process conditions which prevail during filling or emptying operations. While in transport, however, at ambient temperature the UF{sub 6} is solid, and the cylinder interior is well below atmospheric pressure. When the cylinders contain isotopically enriched product (above 1.0 percent U-235), they are transported in protective overpacks which function to guard the cylinders and their contents against thermal or mechanical damage in the event of possible transport accidents. Two bare Model 30B cylinders were accidentally exposed to a storage warehouse fire in which a considerable amount of damage was sustained by stored materials and the building structure, as well as by the cylinder valves and valve protectors. The cylinders were about six years old, and had been cleaned, inspected, hydrotested, and re-certified for service, but were still empty at the time of the fire. The privately-owned cylinders were transferred to DOE for testing and evaluation of the fire damage.

  2. Shaped superconductor cylinder retains intense magnetic field

    Science.gov (United States)

    Hildebrandt, A. F.; Wahlquist, H.

    1964-01-01

    The curve of the inner walls of a superconducting cylinder is plotted from the flux lines of the magnetic field to be contained. This shaping reduces maximum flux densities and permits a stronger and more uniform magnetic field.

  3. Development of accurate dimethyl sulphide primary standard gas mixtures at low nanomole per mole levels in high-pressure aluminium cylinders for ambient measurements

    Science.gov (United States)

    Eon Kim, Mi; Kang, Ji Hwan; Doo Kim, Yong; Lee, Dong Soo; Lee, Sangil

    2018-04-01

    Dimethyl sulphide (DMS) plays an important role in atmospheric chemistry and climate change. Ambient DMS is monitored in a global network and reported at sub-nanomole per mole (nmol/mol) levels. Developing traceable, accurate DMS standards at ambient levels is essential for tracking the long-term trends and understanding the role of DMS in the atmosphere. Gravimetrically prepared gas standards in cylinders are widely used for calibrating instruments. Therefore, a stable primary standard gas mixture (PSM) is required for traceable ambient DMS measurement at remote sites. In this study, to evaluate adsorption loss on the internal surface of the gas cylinder, 6 nmol mol-1 DMS gas mixtures were prepared in three types of aluminium cylinders: a cylinder without a special coating on its internal surface (AL), an Aculife IV  +  III-treated cylinder (AC), and an Experis-treated cylinder (EX). There was little adsorption loss on the EX cylinder, whereas there was substantial adsorption loss on the other two cylinders. The EX cylinder was used to prepare 0.5, 2, 5, and 7 nmol mol-1 DMS PSMs with relative expanded uncertainties of less than 0.4%. The DMS PSMs were analytically verified and consistent within a relative expanded uncertainty of less than 1.2%. The long-term stability of the 7 nmol mol-1 DMS PSM was assessed by tracking the ratio of the DMS to the internal standard, benzene. The results showed that the DMS was stable for about seven months and it was projected to be stable for more than 60 months within a relative expanded uncertainty of 3%.

  4. Numerical estimates of the maximum sustainable pore pressure in anticline formations using the tensor based concept of pore pressure-stress coupling

    Directory of Open Access Journals (Sweden)

    Andreas Eckert

    2015-02-01

    Full Text Available The advanced tensor based concept of pore pressure-stress coupling is used to provide pre-injection analytical estimates of the maximum sustainable pore pressure change, ΔPc, for fluid injection scenarios into generic anticline geometries. The heterogeneous stress distribution for different prevailing stress regimes in combination with the Young's modulus (E contrast between the injection layer and the cap rock and the interbedding friction coefficient, μ, may result in large spatial and directional differences of ΔPc. A single value characterizing the cap rock as for horizontal layered injection scenarios is not obtained. It is observed that a higher Young's modulus in the cap rock and/or a weak mechanical coupling between layers amplifies the maximum and minimum ΔPc values in the valley and limb, respectively. These differences in ΔPc imposed by E and μ are further amplified by different stress regimes. The more compressional the stress regime is, the larger the differences between the maximum and minimum ΔPc values become. The results of this study show that, in general compressional stress regimes yield the largest magnitudes of ΔPc and extensional stress regimes provide the lowest values of ΔPc for anticline formations. Yet this conclusion has to be considered with care when folded anticline layers are characterized by flexural slip and the friction coefficient between layers is low, i.e. μ = 0.1. For such cases of weak mechanical coupling, ΔPc magnitudes may range from 0 MPa to 27 MPa, indicating imminent risk of fault reactivation in the cap rock.

  5. Maximum home blood pressure is a useful indicator of diabetic nephropathy in patients with type 2 diabetes mellitus: KAMOGAWA-HBP study.

    Science.gov (United States)

    Oyabu, Chikako; Ushigome, Emi; Matsumoto, Shinobu; Tanaka, Toru; Hasegawa, Goji; Nakamura, Naoto; Ohnishi, Masayoshi; Tsunoda, Sei; Ushigome, Hidetaka; Yokota, Isao; Tanaka, Muhei; Asano, Mai; Yamazaki, Masahiro; Fukui, Michiaki

    2017-11-01

    Maximum home systolic blood pressure has been shown to predict target organ damage. We aimed to clarify the association between maximum home systolic blood pressure and urine albumin to creatinine ratio, an indicator of early-phase diabetic nephropathy in patients with type 2 diabetes. In 1040 patients, we assessed the relationship of mean or maximum home systolic blood pressure and urine albumin to creatinine ratio, and compared the area under the receiver operating characteristic curve of mean or maximum home systolic blood pressure for diabetic nephropathy (urine albumin to creatinine ratio ⩾30 mg/g Cr). Multivariate linear regression analyses indicated that mean morning systolic blood pressure ( β = 0.010, p blood pressure ( β = 0.008, p blood pressure was 0.667 (0.634-0.700; p blood pressure, as well as mean home systolic blood pressure, was significantly associated with diabetic nephropathy in patients with type 2 diabetes.

  6. An investigation on effects of amputee's physiological parameters on maximum pressure developed at the prosthetic socket interface using artificial neural network.

    Science.gov (United States)

    Nayak, Chitresh; Singh, Amit; Chaudhary, Himanshu; Unune, Deepak Rajendra

    2017-10-23

    Technological advances in prosthetics have attracted the curiosity of researchers in monitoring design and developments of the sockets to sustain maximum pressure without any soft tissue damage, skin breakdown, and painful sores. Numerous studies have been reported in the area of pressure measurement at the limb/socket interface, though, the relation between amputee's physiological parameters and the pressure developed at the limb/socket interface is still not studied. Therefore, the purpose of this work is to investigate the effects of patient-specific physiological parameters viz. height, weight, and stump length on the pressure development at the transtibial prosthetic limb/socket interface. Initially, the pressure values at the limb/socket interface were clinically measured during stance and walking conditions for different patients using strain gauges placed at critical locations of the stump. The measured maximum pressure data related to patient's physiological parameters was used to develop an artificial neural network (ANN) model. The effects of physiological parameters on the pressure development at the limb/socket interface were examined using the ANN model. The analyzed results indicated that the weight and stump length significantly affects the maximum pressure values. The outcomes of this work could be an important platform for the design and development of patient-specific prosthetic socket which can endure the maximum pressure conditions at stance and ambulation conditions.

  7. 76 FR 55736 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2011-09-08

    ... certain of high- and low-pressure compressed gas cylinders, primarily fire extinguishers, by Atlas Fire...- pressure cylinders serviced by Atlas Fire Protection were marked and represented as requalified (visually... damage, serious personal injury, or death could result from the rupture of a cylinder. Cylinders not...

  8. Sound insulation of composite cylindrical shells: a comparison between a laminated and a sandwich cylinder

    OpenAIRE

    Yuan, Chongxin; Roozen, Bert; Bergsma, Otto; Beukers, Adriaan

    2012-01-01

    The fuselages of aircraft are modeled as a cylinder in this paper, and the sound insulations of a sandwich cylinder and a laminated cylinder are studied both experimentally and numerically. The cylinders are excited by an acoustic pressure and a mechanical force respectively. Results show that under acoustic excitation, the sandwich cylinder and the laminated one have a similar sound insulation below 3000 Hz, but the sandwich cylinder has a much larger sound insulation at higher frequencies. ...

  9. Radiation levels on empty cylinders containing heel material

    Energy Technology Data Exchange (ETDEWEB)

    Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  10. Experimental and regression analysis for multi cylinder diesel engine operated with hybrid fuel blends

    Directory of Open Access Journals (Sweden)

    Gopal Rajendiran

    2014-01-01

    Full Text Available The purpose of this research work is to build a multiple linear regression model for the characteristics of multicylinder diesel engine using multicomponent blends (diesel- pungamia methyl ester-ethanol as fuel. Nine blends were tested by varying diesel (100 to 10% by Vol., biodiesel (80 to 10% by vol. and keeping ethanol as 10% constant. The brake thermal efficiency, smoke, oxides of nitrogen, carbon dioxide, maximum cylinder pressure, angle of maximum pressure, angle of 5% and 90% mass burning were predicted based on load, speed, diesel and biodiesel percentage. To validate this regression model another multi component fuel comprising diesel-palm methyl ester-ethanol was used in same engine. Statistical analysis was carried out between predicted and experimental data for both fuel. The performance, emission and combustion characteristics of multi cylinder diesel engine using similar fuel blends can be predicted without any expenses for experimentation.

  11. Nucleate pool boiling, film boiling and single-phase free convection at pressures up to the critical state. Part I: Integral heat transfer for horizontal copper cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Gorenflo, Dieter; Baumhoegger, Elmar; Windmann, Thorsten; Herres, Gerhard [Institut fuer Energie- und Verfahrenstechnik, Universitaet Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany)

    2010-11-15

    Transcritical working cycles for refrigerants have led to increased interest in heat transfer near the Critical State. In general, experimental results for this region differ significantly from those far from it because some fluid properties vary much more there than at a greater distance. In this paper, measurements for two-phase and single-phase free convective heat transfer from an electrically heated copper tube with 25 mm O.D. to refrigerant R125 are discussed for fluid states very close to the Critical Point and far from it. It is shown that heat transfer for film boiling slightly below and for free convection slightly above the critical pressure is very similar. The new - and also previous - experimental data for nucleate boiling, film boiling, and single-phase free convection are compared with calculated results between atmospheric and critical pressure. It can be concluded that the Principle of Corresponding States in its simplest form is very well suited to transfer the results to other refrigerants. In Part II, particular attention will be given to a minimum superheat for nucleate boiling and a maximum superheat for film boiling and single-phase free convection within the circumferential variation of the isobaric wall superheat on the lower parts of the tube. (author)

  12. Optimized thick-wall cylinders by virtue of Poisson's ratio selection

    International Nuclear Information System (INIS)

    Whitty, J.P.M.; Henderson, B.; Francis, J.; Lloyd, N.

    2011-01-01

    The principal stress distributions in thick-wall cylinders due to variation in the Poisson's ratio are predicted using analytical and finite element methods. Analyses of appropriate brittle and ductile failure criteria show that under the isochoric pressure conditions investigated that auextic (i.e. those possessing a negative Poisson's ratio) materials act as stress concentrators; hence they are predicted to fail before their conventional (i.e. possessing a positive Poisson's ratio) material counterparts. The key finding of the work presented shows that for constrained thick-wall cylinders the maximum tensile principal stress can vanish at a particular Poisson's ratio and aspect ratio. This phenomenon is exploited in order to present an optimized design criterion for thick-wall cylinders. Moreover, via the use of a cogent finite element model, this criterion is also shown to be applicable for the design of micro-porous materials.

  13. Optimization study of pressure-swing distillation for the separation process of a maximum-boiling azeotropic system of water-ethylenediamine

    Energy Technology Data Exchange (ETDEWEB)

    Fulgueras, Alyssa Marie; Poudel, Jeeban; Kim, Dong Sun; Cho, Jungho [Kongju National University, Cheonan (Korea, Republic of)

    2016-01-15

    The separation of ethylenediamine (EDA) from aqueous solution is a challenging problem because its mixture forms an azeotrope. Pressure-swing distillation (PSD) as a method of separating azeotropic mixture were investigated. For a maximum-boiling azeotropic system, pressure change does not greatly affect the azeotropic composition of the system. However, the feasibility of using PSD was still analyzed through process simulation. Experimental vapor liquid equilibrium data of water-EDA system was studied to predict the suitability of thermodynamic model to be applied. This study performed an optimization of design parameters for each distillation column. Different combinations of operating pressures for the low- and high-pressure columns were used for each PSD simulation case. After the most efficient operating pressures were identified, two column configurations, low-high (LP+HP) and high-low (HP+ LP) pressure column configuration, were further compared. Heat integration was applied to PSD system to reduce low and high temperature utility consumption.

  14. Optimization study of pressure-swing distillation for the separation process of a maximum-boiling azeotropic system of water-ethylenediamine

    International Nuclear Information System (INIS)

    Fulgueras, Alyssa Marie; Poudel, Jeeban; Kim, Dong Sun; Cho, Jungho

    2016-01-01

    The separation of ethylenediamine (EDA) from aqueous solution is a challenging problem because its mixture forms an azeotrope. Pressure-swing distillation (PSD) as a method of separating azeotropic mixture were investigated. For a maximum-boiling azeotropic system, pressure change does not greatly affect the azeotropic composition of the system. However, the feasibility of using PSD was still analyzed through process simulation. Experimental vapor liquid equilibrium data of water-EDA system was studied to predict the suitability of thermodynamic model to be applied. This study performed an optimization of design parameters for each distillation column. Different combinations of operating pressures for the low- and high-pressure columns were used for each PSD simulation case. After the most efficient operating pressures were identified, two column configurations, low-high (LP+HP) and high-low (HP+ LP) pressure column configuration, were further compared. Heat integration was applied to PSD system to reduce low and high temperature utility consumption.

  15. Dynamical instability of a charged gaseous cylinder

    Science.gov (United States)

    Sharif, M.; Mumtaz, Saadia

    2017-10-01

    In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

  16. Acoustic emission from fiber reinforced plastic damaged hoop wrapped cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, A.; Kung, D.; Westbrook, D.R.

    2000-03-01

    Metal lined continuous fiber reinforced plastic (FRP) hoop wrapped cylinders with axial cuts to the FRP were modeled mathematically and tested experimentally. Steel lined and aluminum alloy lined glass FRP vessels were subjected to acoustic emission tests (AE) and hydraulic burst tests. The burst pressure decreased monotonically with the length of the axial cut. Acoustic emission increased initially with a decrease in burst pressure, and attained a maximum at an intermediate level of damage to the FRP. However, acoustic emission decreased when the level of damage was higher and the burst pressure was lower. Implications of the findings are discussed in the context of the search for an acoustic emission test method to inspect periodically the vessels used for the storage of compressed gaseous fuels on natural gas vehicles (NGV) and hydrogen vehicles.

  17. Method and apparatus for filling cryogenic liquid cylinders

    International Nuclear Information System (INIS)

    Remes, S.

    1984-01-01

    A method and apparatus are disclosed for filling a portable cryogenic liquid cylinder from a large stand tank. The invention employs a regulator valve to perform an automatic throttling function whereby the pressure in the liquid cylinder is maintained at a value slightly lower than the upstream pressure in the stand tank. This significantly reduces filling losses due to flashing

  18. Cylinder monitoring program

    Energy Technology Data Exchange (ETDEWEB)

    Alderson, J.H. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Cylinders containing depleted uranium hexafluoride (UF{sub 6}) in storage at the Department of Energy (DOE) gaseous diffusion plants, managed by Martin Marietta Energy Systems, Inc., are being evaluated to determine their expected storage life. Cylinders evaluated recently have been in storage service for 30 to 40 years. In the present environment, the remaining life for these storage cylinders is estimated to be 30 years or greater. The group of cylinders involved in recent tests will continue to be monitored on a periodic basis, and other storage cylinders will be observed as on a statistical sample population. The program has been extended to all types of large capacity UF{sub 6} cylinders.

  19. Stabilization of flow past a rounded cylinder

    Science.gov (United States)

    Samtaney, Ravi; Zhang, Wei

    2016-11-01

    We perform global linear stability analysis on low-Re flow past a rounded cylinder. The cylinder corners are rounded with a radius R, normalized as R+ = R / D where D is the cylinder diameter, and its effect on the flow stability characteristics is investigated. We compute the critical Reynolds number (Recr) for the onset of first instability, and quantify the perturbation growth rate for the super-critical flows. It is found that the flow can be stabilized by partially rounding the cylinder. Compared with the square and circular cylinders, the partially rounded cylinder has a higher Recr , attaining a maximum at around R+ = 0 . 30 , and the perturbation growth rate of the super-critical flows is reduced for Re R+ -> 0 . 00), while only the near-wake backflow is crucial for circular-like cylinders (R+ -> 0 . 50). The stability analysis results are also verified with those of the direct simulations and very good agreement is achieved. Supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1394-01. The supercomputer Shaheen at KAUST was utilized for the simulations.

  20. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular...... antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...

  1. Maximum inspiratory pressure as a clinically meaningful trial endpoint for neuromuscular diseases: A comprehensive review of the literature

    NARCIS (Netherlands)

    B. Schoser; Fong, E. (Edward); Geberhiwot, T. (Tarekegn); Hughes, D. (Derralynn); Kissel, J.T. (John T.); Madathil, S.C. (Shyam C.); Orlikowski, D. (David); Polkey, M.I. (Michael I.); M. Roberts (Mark); H.A.W.M. Tiddens (Harm); Young, P. (Peter)

    2017-01-01

    textabstractRespiratory muscle strength is a proven predictor of long-term outcome of neuromuscular disease (NMD), including amyotrophic lateral sclerosis, Duchenne muscular dystrophy, and spinal muscular atrophy. Maximal inspiratory pressure (MIP), a sensitive measure of respiratory muscle

  2. Approximation by Cylinder Surfaces

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1997-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...

  3. A Study of Gas Economizing Pneumatic Cylinder

    International Nuclear Information System (INIS)

    Li, T C; Wu, H W; Kuo, M J

    2006-01-01

    The pneumatic cylinder is the most typical actuator in the pneumatic equipment, and its mechanism is so simple that it is often used to operate point to point driving without the feedback loop in various automatic machines. But, the energy efficiency of pneumatic system is very poor compared with electrical systems and hydraulic systems. So, it is very important to discuss the energy saving for the pneumatic cylinder systems. In this thesis, we proposed three methods to apply the reduction in the air consumed for pneumatic cylinder systems. An air charge accumulator is used to absorb the exhausted compress air and a boost valve boosted the air to the higher pressure for used again. From the experiments, the direct used cylinder exhaust air may save about 40% of compress air

  4. Numerical Study of Shock-Cylinder Banks Interactions

    International Nuclear Information System (INIS)

    Wang, S.P.; Anderson, M.H.; Oakley, J.G.; Bonazza, R.

    2003-01-01

    A numerical parametric study of shock-cylinder banks interactions is presented using a high resolution Euler solver. Staggered cylinder banks of five rows are chosen with the purpose of modeling IFE reactor cooling tube banks. The effect of the aspect ratio of the intercylinder pitch to the distance between successive cylinder rows on the vertical pressure forces acting on the cylinders with different geometries is investigated. Preliminary results show that the largest vertical force develops on the cylinders of the second or third row. This peak pressure force increases with decreasing values of the aspect ratio. It is shown that an increasing second force peak also appears on the successive rows, starting with the second one, with decreasing aspect ratio. It is also observed that the force on the last-row cylinders basically decreases to the level of that on the first row. The results are useful for the optimal design of the cooling tubes system of IFE reactors

  5. MEMS pressure sensor with maximum performances by using novel back-side direct-exposure concept featuring through glass vias

    Science.gov (United States)

    Mukhopadhyay, B.; Fritz, M.; Mackowiak, P.; Vu, T. C.; Ehrmann, O.; Lang, K.-D.; Ngo, H.-D.

    2013-05-01

    Design, simulation, fabrication, and characterization of novel MEMS pressure sensors with new back-side-direct-exposure packaging concept are presented. The sensor design is optimized for harsh environments e.g. space, military, offshore and medical applications. Unbreakable connection between the active side of the Si-sensor and the protecting glass capping was realized by anodic bonding using a thin layer of metal. To avoid signal corruption of the measured pressure caused by an encapsulation system, the media has direct contact to the backside of the Si membrane and can deflect it.

  6. The effectiveness of combining inspiratory muscle training with manual therapy and a therapeutic exercise program on maximum inspiratory pressure in adults with asthma: a randomized clinical trial.

    Science.gov (United States)

    López-de-Uralde-Villanueva, Ibai; Candelas-Fernández, Pablo; de-Diego-Cano, Beatriz; Mínguez-Calzada, Orcález; Del Corral, Tamara

    2018-06-01

    The objective of this study was to evaluate whether the addition of manual therapy and therapeutic exercise protocol to inspiratory muscle training was more effective in improving maximum inspiratory pressure than inspiratory muscle training in isolation. This is a single-blinded, randomized controlled trial. In total, 43 patients with asthma were included in this study. The patients were allocated into one of the two groups: (1) inspiratory muscle training ( n = 21; 20-minute session) or (2) inspiratory muscle training (20-minute session) combined with a program of manual therapy (15-minute session) and therapeutic exercise (15-minute session; n = 22). All participants received 12 sessions, two days/week, for six weeks and performed the domiciliary exercises protocol. The main measures such as maximum inspiratory pressure, spirometric measures, forward head posture, and thoracic kyphosis were recorded at baseline and after the treatment. For the per-protocol analysis, between-group differences at post-intervention were observed in maximum inspiratory pressure (19.77 cmH 2 O (11.49-28.04), P < .05; F = 22.436; P < .001; η 2 p  = 0.371) and forward head posture (-1.25 cm (-2.32 to -0.19), P < .05; F = 5.662; P = .022; η 2 p  = 0.13). The intention-to-treat analysis showed the same pattern of findings. The inspiratory muscle training combined with a manual therapy and therapeutic exercise program is more effective than its application in isolation for producing short-term maximum inspiratory pressure and forward head posture improvements in patients with asthma.

  7. Fiber Tracking Cylinder Nesting

    International Nuclear Information System (INIS)

    Stredde, H.

    1999-01-01

    The fiber tracker consists of 8 concentric carbon fiber cylinders of varying diameters, from 399mm to 1032.2mm and two different lengths. 1.66 and 2.52 meters. Each completed cylinder is covered over the entire o.d. with scintillating fiber ribbons with a connector on each ribbon. These ribbons are axial (parallel to the beam line) at one end and stereo (at 3 deg. to the beam line) at the other. The ribbon connectors have dowel pins which are used to match with the connectors on the wave guide ribbons. These dowel pins are also used during the nesting operation, locating and positioning measurements. The nesting operation is the insertion of one cylinder into another, aligning them with one another and fastening them together into a homogeneous assembly. For ease of assembly. the nesting operation is accomplished working from largest diameter to smallest. Although the completed assembly of all 8 cylinders glued and bolted together is very stiff. individual cylinders are relatively flexible. Therefore. during this operation, No.8 must be supported in a manner which maintains its integrity and yet allows the insertion of No.7. This is accomplished by essentially building a set of dummy end plates which replicate a No.9 cylinder. These end plates are mounted on a wheeled cart that becomes the nesting cart. Provisions for a protective cover fastened to these rings has been made and will be incorporated in finished product. These covers can be easily removed for access to No.8 and/or the connection of No.8 to No.9. Another wheeled cart, transfer cart, is used to push a completed cylinder into the cylinder(s) already mounted in the nesting cart.

  8. Washing water treatment process for UF{sub 6} cylinder by adjusting evaporation technology in a low temperature and low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-tae; Ju, Young-jong; Cho, Nam-chan [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of); Kim, Yun-kwan; Jin, Chang-suk [Jeontech CO., Suwon (Korea, Republic of)

    2016-10-15

    The liquid waste is treated in this procedure; 1) Add NaOH to the liquid waste and filter the mixture with a screen. 2) Screened residue is dried and then stored in a uranium storage. 3) liquid part is moved to a storage tank and radioactivity is measured in the liquid. 5) If the concentration of radioactivity is lower than corresponding regulation limit, the liquid moved to a reaction tank and evaporated with additional low concentration HF in 105℃. 6) Radioactivity of distillate is measured and the value is lower than regulation, it is treated with a thermal decomposition process and discharged to the atmosphere in gas state. 7) Solid waste produced in the evaporation step is managed as solid nuclear waste. The treatment procedure mentioned above has disadvantageous points, producing large amount of solid waste as well as, high energy and chemical consumption. In this study, liquid waste from a real scaled cylinder wash process is applied to evaporation system to confirm feasibility of the application of evaporation and, to reduce waste production and energy consumption. Liquid radioactive wastewater from a real scaled UF6 cylinder wash process was applied to evaporation treatment system. Radioactive concentration in gross alpha was removed 99.9% in the evaporation system. And the concentration in distillate was lower than the discharge regulation. Removal of U-235 was 99.9% in the process. And 15 other kinds of radionuclides in the raw wastewater were removed completely. Secondary waste production of the evaporation system is 15g/L.

  9. Modeling of thermodynamic non-equilibrium flows around cylinders and in channels

    Science.gov (United States)

    Sinha, Avick; Gopalakrishnan, Shiva

    2017-11-01

    Numerical simulations for two different types of flash-boiling flows, namely shear flow (flow through a de-Laval nozzle) and free shear flow (flow past a cylinder) are carried out in the present study. The Homogenous Relaxation Model (HRM) is used to model the thermodynamic non-equilibrium process. It was observed that the vaporization of the fluid stream, which was initially maintained at a sub-cooled state, originates at the nozzle throat. This is because the fluid accelerates at the vena-contracta and subsequently the pressure falls below the saturation vapor pressure, generating a two-phase mixture in the diverging section of the nozzle. The mass flow rate at the nozzle was found to decrease with the increase in fluid inlet temperature. A similar phenomenon also occurs for the free shear case due to boundary layer separation, causing a drop in pressure behind the cylinder. The mass fraction of vapor is maximum at rear end of the cylinder, where the size of the wake is highest. As the back pressure is reduced, severe flashing behavior was observed. The numerical simulations were validated against available experimental data. The authors gratefully acknowledge funding from the public-private partnership between DST, Confederation of Indian Industry and General Electric Pvt. Ltd.

  10. Gas Cylinder Safety, Course 9518

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-27

    This course, Gas Cylinder Safety (#9518), presents an overview of the hazards and controls associated with handling, storing, using, and transporting gas cylinders. Standard components and markings of gas cylinders are also presented, as well as the process for the procurement, delivery, and return of gas cylinders at Los Alamos National Laboratory (LANL).

  11. Cylinder gauge measurement using a position sensitive detector

    International Nuclear Information System (INIS)

    St John, W. Doyle

    2007-01-01

    A position sensitive detector (PSD) has been used to determine the diameter of cylindrical pins based on the shift in a laser beam's centroid. The centroid of the light beam is defined here as the weighted average of position by the local intensity. A shift can be observed in the centroid of an otherwise axially symmetric light beam, which is partially obstructed. Additionally, the maximum shift in the centroid is a unique function of the obstructing cylinder diameter. Thus to determine the cylinder diameter, one only needs to detect this maximum shift as the cylinder is swept across the beam

  12. Design of a single cylinder optical access to the combustion engine Scania D12

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Juergen

    2000-11-01

    In this work a maximum optical access to a diesel engine is developed. The combustion-process in the engine should be representative to the one in a standard engine, so the geometry of the combustion chamber is modified as little as possible. A Scania single cylinder, 2-litre engine was subjected to modifications allowing the optical access. Solutions to these problems are obtained by using the method of Product-Development, mainly based on the literature by Prof Dr.-Ing. Birkhofer at the Technical University of Darmstadt, Germany. An optical engine design of the Bowditch type was the chosen main working principle. This engine contains an extended cylinder, partly made of glass, a glass piston-crown and a mirror placed inside the extended piston. The laser sheet is led into the combustion chamber through the glass part of the cylinder, then gets reflected inside the combustion chamber and is led through the glass piston crown and via the mirror out of the engine. A redesign of the valve-train, using extended push-rods, is necessary. The demand to examine the combustion at Top-Dead-Centre (TDC) and the necessity of supporting the glass, give the reasons to do work on the cylinder head. This in return brings sealing problems, which have been solved. Another problem that occurs with that type of engine is that is has to run without oil-lubrication. Piston rings made of Rylon are used to solve this problem. A special feature of the engine that has been constructed here is that the inner surface of the glass may be cleaned without removing the cylinder head. This is obtained by a construction with a movable cylinder. In cleaning-state the cylinder is driven up and down together with the piston, while the head is supported by an outer structure. When running the engine, the cylinder is fixed to the structure. Furthermore this report contains the necessary calculations and integrity assessments on the critical parts of the construction. All calculations, except the

  13. Mechanical Integrity of Copper Canister Lid and Cylinder. Sensitivity study

    International Nuclear Information System (INIS)

    Karlsson, Marianne

    2002-08-01

    This report is part of a study of the mechanical integrity of canisters used for disposal of nuclear fuel waste. The overall objective is to determine and ensure the static and long-term strength of the copper canister lid and cylinder casing. The canisters used for disposal nuclear fuel waste of type BWR consists of an inner part (insert) of ductile cast iron and an outer part of copper. The copper canister is to provide a sealed barrier between the contents of the canister and the surroundings. The study in this report complements the finite element analyses performed in an earlier study. The analyses aim to evaluate the sensitivity of the canister to tolerances regarding the gap between the copper cylinder and the cast iron insert. Since great uncertainties regarding the material's long term creep properties prevail, analyses are also performed to evaluate the effect of different creep data on the resulting strain and stress state. The report analyses the mechanical response of the lid and flange of the copper canister when subjected to loads caused by pressure from swelling bentonite and from groundwater at a depth of 500 meter. The loads acting on the canister are somewhat uncertain and the cases investigated in this report are possible cases. Load cases analysed are: Pressure 15 MPa uniformly distributed on lid and 5 MPa uniformly distributed on cylinder; Pressure 5 MPa uniformly distributed on lid and 15 MPa uniformly distributed on cylinder; Pressure 20 MPa uniformly distributed on lid and cylinder; and Side pressures 10 MPa and 20 MPa uniformly distributed on part of the cylinder. Creep analyses are performed for two of the load cases. For all considered designs high principal stresses appear on the outside of the copper cylinder in the region from the weld down to the level of the lid lower edge. Altering the gap between lid and cylinder and/or between cylinder and insert only marginally affects the resulting stress state. Fitting the lid in the cylinder

  14. Effect of error in crack length measurement on maximum load fracture toughness of Zr-2.5Nb pressure tube material

    International Nuclear Information System (INIS)

    Bind, A.K.; Sunil, Saurav; Singh, R.N.; Chakravartty, J.K.

    2016-03-01

    Recently it was found that maximum load toughness (J max ) for Zr-2.5Nb pressure tube material was practically unaffected by error in Δ a . To check the sensitivity of the J max to error in Δ a measurement, the J max was calculated assuming no crack growth up to the maximum load (P max ) for as received and hydrogen charged Zr-2.5Nb pressure tube material. For load up to the P max , the J values calculated assuming no crack growth (J NC ) were slightly higher than that calculated based on Δ a measured using DCPD technique (JDCPD). In general, error in the J calculation found to be increased exponentially with Δ a . The error in J max calculation was increased with an increase in Δ a and a decrease in J max . Based on deformation theory of J, an analytic criterion was developed to check the insensitivity of the J max to error in Δ a . There was very good linear relation was found between the J max calculated based on Δ a measured using DCPD technique and the J max calculated assuming no crack growth. This relation will be very useful to calculate J max without measuring the crack growth during fracture test especially for irradiated material. (author)

  15. Mathematic modelling of circular cylinder deformation under inner grouwth

    Directory of Open Access Journals (Sweden)

    A. V. Siasiev

    2009-09-01

    Full Text Available A task on the intensive deformed state (IDS of a viscoelastic declivous cylinder, which is grown under the action of inner pressure, is considered. The process of continuous increase takes a place on an internal radius so, that a radius and pressure change on set to the given law. The special case of linear law of creeping is considered, and also numeral results are presented as the graphs of temporal dependence of tensions and moving for different points of cylinder.

  16. An update on corrosion monitoring in cylinder storage yards

    Energy Technology Data Exchange (ETDEWEB)

    Henson, H.M.; Newman, V.S.; Frazier, J.L. [Oak Ridge K-25 Site, TN (United States)

    1991-12-31

    Depleted uranium, from US uranium isotope enrichment activities, is stored in the form of solid uranium hexafluoride (UF{sub 6}) in A285 and A516 steel cylinders designed and manufactured to ASME Boiler and Pressure Vessel Code criteria. In general, storage facilities are open areas adjacent to the enrichment plants where the cylinders are exposed to weather. This paper describes the Oak Ridge program to determine the general corrosion behavior of UF{sub 6} cylinders, to determine cylinder yard conditions which are likely to affect long term storage of this material, and to assess cylinder storage yards against these criteria. This program is targeted at conditions specific to the Oak Ridge cylinder yards. Based on (a) determination of the current cylinder yard conditions, (b) determination of rusting behavior in regions of the cylinders showing accelerated attack, (c) monitoring of corrosion rates through periodic measurement of test coupons placed within the cylinder yards, and (d) establishment of a computer base to incorporate and retain these data, the technical division is working with the enrichment sites to implement an upgraded system for storage of this material until such time as it is used or converted.

  17. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    OpenAIRE

    Ma Xiaobing; Zhang Yongbo

    2015-01-01

    An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life ...

  18. Rolling Cylinder Phase 1

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Taraborrelli, Valeria Taraborrelli

    Margheritini and Valeria Taraborrelli(valeria.taraborrelli@hotmail.it) with a total of 3 day visit from the developers. Laboratory tests in irregular waves will be performed by Lucia Margheritini. The report is aimed at the first stage testing of the Rolling Cylinder wave energy device. This phase includes...

  19. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 2

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.

    1975-10-01

    Model 2 in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. Both the cylinder and the nozzle of model 2 had outside diameters of 10 in., giving a d 0 /D 0 ratio of 1.0, and both had outside diameter/thickness ratios of 100. Sixteen separate loading cases in which one end of the cylinder was rigidly held were analyzed. An internal pressure loading, three mutually perpendicular force components, and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. In addition to these 13 loadings, 3 additional loads were applied to the nozzle (in-plane bending moment, out-of-plane bending moment, and axial force) with the free end of the cylinder restrained. The experimental stress distributions for each of the 16 loadings were obtained using 152 three-gage strain rosettes located on the inner and outer surfaces. All the 16 loading cases were also analyzed theoretically using a finite-element shell analysis. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good general agreement, and it is felt that the analysis would be satisfactory for most engineering purposes. (auth)

  20. Nitrided steel with increased reliability for steam turbine blades of low pressure cylinders; Vysokoazotistaya stal` s povishennoj nadezhdnostni dlya lopatok ha tsilindrov niskogo davleniya parnikh turbin

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, Ch; Lengarski, P [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Metaloznanie i Tekhnologiya na Metalite

    1996-12-31

    A new type of steel has been developed, containing 0.11-0.20% N and less than 0.05% C, the sum of both components being within the range 0.16-0.26%. The metal has an austenite-martensite structure with 10-30% austenite content. Samples obtained by counter-pressure casting have been investigated with respect to the influence of the thermal treatment on mechanical properties. The best properties are obtained when applying hardening by heating at 1050{sup o} C and cooling at 550{sup o} C: fluidity limit R{sub 0}.2>=850 MPa, relative elongation A>=15%, relative shortening Z>=50%, impact viscosity KCU >= 588 kJ/m{sup 2} at critical temperature of brittleness <-40{sup o} C. These properties are combined with high corrosion and wear resistance and make the steel suitable for steam turbine blades. 5 refs., 2 figs., 4 tabs.

  1. Prediction of External Corrosion for Steel Cylinders--2007 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, Richard L [ORNL

    2008-01-01

    , top or bottom row storage positions, etc. These models are then used to compute projections of numbers of cylinders expected to fail various minimum wall thickness criteria. The minimum wall thickness criteria are as follows. For thin-wall cylinders: 0 (breach), 62.5, and 250 mils. For thick-wall cylinders: 0, 62.5, and 500 mils. For 30A cylinders: 0, 62.5, and 100 mils. Each of these criteria triplets are based respectively on (1) loss of DUF{sub 6} (breaching), (2) safe handling and stacking operations, and (3) ANSI N14.1 standards for off-site transport and contents transfer. This report complements and extends previous editions of the cylinder corrosion report by Lyon (1995, 1996, 1997, 1998, 2000), by Schmoyer and Lyon (2001, 2002, 2003), and by Schmoyer (2004). These reports are based on UT data collected in FY03 and before. In this report UT data collected after FY03 but before FY07 is combined with the earlier data, and all of the UT data is inventoried chronologically and by the various functional groups. The UT data is then used to fit models of maximum pit depth and minimum wall thickness, statistical outliers are investigated, and the fitted models are used to extrapolate minimum thickness estimates into the future and in turn to compute projections of numbers of cylinders expected to fail various thickness criteria. A model evaluation is performed comparing UT measurements made after FY05 with model-fitted projections based only on data collected in FY05 and before. As in previous reports, the projections depend on the treatment of outliers.

  2. Uniform flow around a circular cylinder in the subcritical range - using the Self-induced angular Moment Method turbulence model

    DEFF Research Database (Denmark)

    Johansson, Jens; Nielsen, Mogens Peter

    The uniform flow around a circular cylinder at Reynolds number 1e5 is simulated in a three dimensional domain by means of the newly developed Self-induced angular Moment Method, SMoM, turbulence model. The global force coefficients, Strouhal number, pressure distributions and wall shear stress...... distributions are compared to experimental findings reported in literature. The SMoM turbulence model is found to provide maximum, minimum and time-mean pressure coefficient distributions in very good agreement with experimental findings....

  3. Prediction of External Corrosion for Steel Cylinders--2004 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2004-07-07

    Depleted uranium hexafluoride (UF{sub 6}) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF{sub 6} Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF{sub 6} and the cylinders containing it. This report documents activities that address UF{sub 6} Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to fail various thickness criteria are computed from corrosion models relating minimum wall thickness to cylinder age, initial thickness estimates, and cylinder subpopulations defined in terms of plant site, yard, top or bottom storage positions, nominal thickness, etc. In this report, UT data collected during FY03 is combined with UT data collected in earlier years (FY94-FY02), and all of the data is inventoried chronologically and by various subpopulations. The UT data is used to fit models of maximum pit depth and minimum thickness, and the fitted models are used to extrapolate minimum thickness estimates into the future and in

  4. Prediction of External Corrosion for Steel Cylinders--2004 Report

    International Nuclear Information System (INIS)

    Schmoyer, RLS

    2004-01-01

    Depleted uranium hexafluoride (UF 6 ) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF 6 Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF 6 and the cylinders containing it. This report documents activities that address UF 6 Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to fail various thickness criteria are computed from corrosion models relating minimum wall thickness to cylinder age, initial thickness estimates, and cylinder subpopulations defined in terms of plant site, yard, top or bottom storage positions, nominal thickness, etc. In this report, UT data collected during FY03 is combined with UT data collected in earlier years (FY94-FY02), and all of the data is inventoried chronologically and by various subpopulations. The UT data is used to fit models of maximum pit depth and minimum thickness, and the fitted models are used to extrapolate minimum thickness estimates into the future and in turn to compute

  5. Cylinder head seal for piston engines especially internal combustion engines. Zylinderkopfdichtung fuer Hubkolbenmaschinen, insbesondere Brennkraftmaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, H.; Winter, J.

    1991-01-17

    The invention concerns a cylinder head seal for reciprocating piston engines especially internal combustion engines and preferentially those with cylinder sleeves. With performances of internal combustion engines encreasing all the time it is becoming more and more difficult to seal the cylinder heat. The invention proposes a ring seal whose sides are plastically deformed when the cylinder headed screws are tightened. The inner deformations of the cylinder head resulting from the pressure forces inside the cylinder are compensated by means of elastic spring action of the combustion chamber sealing ring. The dimension of land, groove and sides are matched in such a way as to prevent any seal squeezing during plastification which would result in a deformation of the cylinder sleeve. The ring can therefore be set directly into the centering of the cylinder sleeve. Separate centering devices are not required.

  6. Mechanical Cushion Design Influence on Cylinder Dynamics

    DEFF Research Database (Denmark)

    Borghi, Massimo; Milani, Massimo; Conrad, Finn

    2005-01-01

    The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow....... experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined...

  7. Cylinder Position Servo Control Based on Fuzzy PID

    Directory of Open Access Journals (Sweden)

    Shibo Cai

    2013-01-01

    Full Text Available The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm.

  8. The Friction of Vehicle Brake Tandem Master Cylinder

    International Nuclear Information System (INIS)

    Kao, M J; Chang, H; Tsung, T T; Lin, H M

    2006-01-01

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications

  9. A numerical simulation of VIV on a flexible circular cylinder

    International Nuclear Information System (INIS)

    Xie Fangfang; Deng Jian; Zheng Yao; Xiao Qing

    2012-01-01

    In this paper, numerical simulations of a flexible circular cylinder subjected to a vortex-induced vibration (VIV) are conducted. The Reynolds number for simulations is fixed at 1000. The finite volume method is applied for modeling fluid flow with the moving meshes feature. The dynamic response of a flexible cylinder fixed at both ends is modeled by the Euler–Bernoulli beam theory. The comparison between two-dimensional (2D) simulations and 3D simulations for the flexible cylinder shows that the maximum response amplitude of the cross-flow oscillation is about 0.57D for 2D rigid cylinders (modeled by a spring–damper–mass model) and 1.03D for flexible cylinders, respectively. The results from 3D simulations are closer to previous experimental results. Furthermore, the results obtained with various frequency ratios show that different wake patterns exist according to the frequency ratio, such as 2S mode, 2P mode and some more complicated modes. The wake pattern is different at various sections along the cylinder length, due to the fact that the two ends of the beam are fixed. The vibration of the flexible cylinder can also greatly alter the three dimensionality in the wake, which is our research in future work, especially in the transition region for Reynolds number ranging from 170 to 300. (paper)

  10. Experimental investigation of turbulent flow past four grooved and smooth cylinders in an in-line square arrangement

    Directory of Open Access Journals (Sweden)

    Ladjedel O.

    2015-01-01

    Full Text Available An experimental study of turbulent flow past four cylinders in square arrangement with a space ratio of (T/D = P/D = 2.88 is performed. The investigation focuses on effects of Reynolds number and the shape of cylinders on the force and pressure coefficients of the cylinders. Two cases are investigated: four smooth cylinders (case1 and four grooved cylinders (case2. The cylinders are equipped with two grooves placed on the external surface at 90° and 270° degrees. The pressure distributions along the tubes (22 circumferential pressure taping were determined for a variation of the azimuthal angle from 0 to 360deg. The drag and lift forces are measured using the TE 44 balance. The results show a bistable flow often exists behind the downstream cylinders is observed. By rising the Reynolds number the pressure coefficient increases in the absolute value.

  11. Plane Wall Effect of Flow around Two Circular Cylinders in Tandem Arrangement

    Directory of Open Access Journals (Sweden)

    Triyogi Yuwono,

    2011-02-01

    Full Text Available The flow characteristic around two circular cylinders in tandem arrangement located near a plane wall were investigated experimentally in a uniform flow at a Reynolds Number of 5.3 x 104. The center to center spacing between the two cylinders relative to the cylinder diameter was constantly maintained at P/D = 1.5. The pressure distributions along the surface of the cylinder and the plane wall were measured by varying the gap-to-diameter of cylinder ratio (G/D in the range of 0 < G/D < 0.467. Surface oil-film techniques were used to investigate the flow patterns on the cylinder. The result showed that for upstream cylinder, in the gap-to-diameter ratio G/D < /D, there is no stagnation point at front side of the upstream cylinder; it is gradually raised as the gap increase. For the downstream cylinder, a peak on the lower side of the front side of the cylinder is apparent in each of the pressure distributions. This peak represents the reattachment of shear layer that separates from lower side of the upstream cylinder. The reattachment point tends to move forward close to the angular position of  = 0o as the gap ratio increase. The shear layer bifurcates into two shear layers. One shear layer continues in the downstream direction, and the other shear layer flows in the upstream direction.

  12. Fluid structural response of axially cracked cylinders

    International Nuclear Information System (INIS)

    Garnich, M.R.; Simonen, F.A.

    1985-03-01

    The fluid structural (FS) response of a cylindrical pressure vessel to a suddenly occurring longitudinal through-wall crack is predicted. The effects of vessel internals and depressurization of the compressed water on dynamic crack opening displacements are investigated. A three dimensional (3D) structural finite element model is used as a basis for the development of a two dimensional (2D) FS model. A slice of the vessel taken at the crack midspan and normal to the cylinder axis is modeled. Crack opening displacements are compared between the 2D and 3D models, between the different assumptions about fluid depressurization, and between the static and dynamic solutions. The results show that effects of dynamic amplification associated with the sudden opening of the crack in the cylinder are largely offset by the local depressurization of the fluid adjacent to the crack

  13. The provision of clearances accuracy in piston - cylinder mating

    Science.gov (United States)

    Glukhov, V. I.; Shalay, V. V.

    2017-08-01

    The paper is aimed at increasing the quality of the pumping equipment in oil and gas industry. The main purpose of the study is to stabilize maximum values of productivity and durability of the pumping equipment based on the selective assembly of the cylinder-piston kinematic mating by optimization criterion. It is shown that the minimum clearance in the piston-cylinder mating is formed by maximum material dimensions. It is proved that maximum material dimensions are characterized by their own laws of distribution within the tolerance limits for the diameters of the cylinder internal mirror and the outer cylindrical surface of the piston. At that, their dispersion zones should be divided into size groups with a group tolerance equal to half the tolerance for the minimum clearance. The techniques for measuring the material dimensions - the smallest cylinder diameter and the largest piston diameter according to the envelope condition - are developed for sorting them into size groups. Reliable control of the dimensions precision ensures optimal minimum clearances of the piston-cylinder mating in all the size groups of the pumping equipment, necessary for increasing the equipment productivity and durability during the production, operation and repair processes.

  14. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 3

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Corum, J.M.; Bryson, J.W.

    1975-06-01

    The third in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: the experimental data provide design information directly applicable to nozzles in cylindrical vessels; and the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 3 had a 10 in. OD and the nozzle had a 1.29 in. OD, giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios for the cylinder and the nozzle were 50 and 7.68 respectively. Thirteen separate loading cases were analyzed. In each, one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for all the loadings were obtained using 158 three-gage strain rosettes located on the inner and outer surfaces. The loading cases were also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

  15. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 4

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.

    1975-06-01

    The last in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models in the series are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: (1) the experimental data provide design information directly applicable to nozzles in cylindrical vessels, and (2) the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 4 had an outside diameter of 10 in., and the nozzle had an outside diameter of 1.29 in., giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios were 50 and 20.2 for the cylinder and nozzle respectively. Thirteen separate loading cases were analyzed. For each loading condition one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for each of the 13 loadings were obtained using 157 three-gage strain rosettes located on the inner and outer surfaces. Each of the 13 loading cases was also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

  16. Experimental Study on Natural Convection Heat Transfer From two Parallel Horizontal Cylinders in Horizontal Cylindrical Enclosure

    Directory of Open Access Journals (Sweden)

    Ahmed T. Ahmed

    2013-05-01

    Full Text Available  An experimental study on natural convection heat transfer from two parallel horizontal cylinders in horizontal cylindrical enclosure was carried out under condition of constant surfaces temperature for two cylinders and cylindrical enclosure. The study included the effect of Rayleigh number, rotation angle that represent the confined angle between the passing horizontal plane in cylindrical enclosure center and passing line in two cylinders centers, and the spaces between two cylinders on their heat loss ability.39An experimental set-up was used for this purpose which consist watercontainer, test section which is formed of plastic cylinder that represent the cylindrical enclosure, and two heating elements which are formed of two copper cylinders with (19 mm in diameters heated internally by electrical sources that represents transfer and heat loss elements through this set-up.      The experiments were done at the range of Rayleigh number between ( , cylinders rotation angle at ( , and spacing ratio at ( .     The study showed that the ability of heat loss from two cylinders is a function of Rayleigh number, cylinders rotation angle, and the spaces between them. This ability is increased by increasing of Rayleigh number and it was showed that this ability reaches maximum value at the first cylinder ( and minimum value at the second cylinder ( at spacing ratio (S/D=3 and rotation angle ( for the first and ( for the second cylinder respectively.      The effective variables on natural convection heat transfer from the above two cylinders are related by two correlating equations, each one explains dimensionless relation of heat transfer from each cylinder that represented by Nusselt number against Rayleigh number, rotation angle, and the spacing ratio between two cylinders

  17. Approximation of Surfaces by Cylinders

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1998-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...

  18. Effects of moisture migration on shrinkage, pore pressure and other concrete properties

    International Nuclear Information System (INIS)

    Chapman, D.A.; England, G.L.

    1977-01-01

    This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder, transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. The rate at which this drying front, moves is influenced by the base temperature, the magnitude of temperature and pressure gradients and the coefficient of permeability of the concrete. Samples taken from the hot side of the drying front show a considerable increase in the coefficient of permeability, and Scanning Electron Microscope photographs of the microstructure show both a break-up and reduction in size of the hydration products. The experiments reported indicate that when the hot inner face temperature of a concrete pressure vessel is increased above 100 0 C, the drying rate inside the wall increases considerably, However, it is unlikely pressure vessels of the size currently in use will ever completely dry out. (Auth.)

  19. Flow past a rotating cylinder

    Science.gov (United States)

    Mittal, Sanjay; Kumar, Bhaskar

    2003-02-01

    Flow past a spinning circular cylinder placed in a uniform stream is investigated via two-dimensional computations. A stabilized finite element method is utilized to solve the incompressible Navier Stokes equations in the primitive variables formulation. The Reynolds number based on the cylinder diameter and free-stream speed of the flow is 200. The non-dimensional rotation rate, [alpha] (ratio of the surface speed and freestream speed), is varied between 0 and 5. The time integration of the flow equations is carried out for very large dimensionless time. Vortex shedding is observed for [alpha] cylinder. The results from the stability analysis for the rotating cylinder are in very good agreement with those from direct numerical simulations. For large rotation rates, very large lift coefficients can be obtained via the Magnus effect. However, the power requirement for rotating the cylinder increases rapidly with rotation rate.

  20. Krypton gas cylinders as a source of radiation.

    Science.gov (United States)

    Fischer, Helmut W; Bielefeld, Tom; Hettwig, Bernd

    2010-07-01

    A standard 40 foot shipping container with a cargo of pressurized krypton gas in 159 steel cylinders, which had triggered a radiation alarm, was investigated to address radiation safety and illicit nuclear trafficking concerns. The investigation included contamination and dose rate measurements as well as in situ high resolution gamma spectroscopy. The dose rate measurements gave a maximum value of 0.07 microSv h(-1) above background (0.08 to 0.11 microSv h(-1)) on the cylinder surface and no detectable increase above background at distances of 1 m and higher. Contamination monitor readings showed a similar relative increase (plus 8 cpm) above background (about 12 cpm) to the dose rate readings. Quantitative gamma spectroscopy revealed a contamination of the gas with 85Kr at a level of 3.5 x 10(5) Bq kg(-1). This value was found to be consistent with analytical and numerical estimates based on current data for atmospheric 85Kr, which is captured from ambient air together with stable krypton during the production process. This incident demonstrates an apparent lack of radiation-related knowledge by those who handle krypton gas, as well as by border control personnel and emergency responders. We therefore propose to improve labeling and documentation standards for such shipments. This effort may be facilitated by introducing the new category of "technically enhanced artificial radioactive material," or "TEARM" (similar to the existing "naturally occurring radioactive material" or "NORM" and "technically enhanced naturally occurring radioactive material" or "TENORM" categories).

  1. Improvement of the Magnetic Shielding Effects by the Superposition of a Multi-Layered Ferromagnetic Cylinder over an HTS Cylinder: Relationship Between the Shielding Effects and the Layer Number of the Ferromagnetic Cylinder

    International Nuclear Information System (INIS)

    Yasui, K; Tarui, Y; Itoh, M

    2006-01-01

    The idealized magnetic shielded vessel can be realized by making use of a high-critical temperature superconductor (HTS). It is difficult for practical applications, however, to fabricate a shielding vessel that has a high value of the maximum shielded magnetic flux density B s0 . The present authors have improved the value of B s0 for the Bi-Pb-Sr-Ca-Cu-O (BPSCCO) cylinder used as the shielding vessel, by the superposition of a four-layered softiron cylinder over the BPSCCO cylinder, termed the four-layered superimposed cylinder. The B s4 value of 610 x 10 -4 T for the four-layered superimposed cylinder, is found to be about 4 times larger than that of a single-BPSCCO cylinder, and is theoretically analyzed by use of a new analysis method. The experimental values of the maximum shielded magnetic flux density B sn of n-layered superimposed cylinders are found to agree well with those of the theoretical analysis. Experimental results revealed several characteristics of the magnetic shielding within the n-layered superimposed cylinders. Also discussed is the new analysis method for the relationship between the n and B sn

  2. Criticality safety review of 2 1/2-, 10-, and 14-ton UF6 cylinders

    International Nuclear Information System (INIS)

    Broadhead, B.L.

    1991-10-01

    Currently, UF 6 cylinders designed to contain 2 1/2 tons of UF 6 are classified as Fissile Class 2 packages with a transport index (TI) of 5 for the purpose of transportation. The 10-ton UF 6 cylinders are classified as Fissile Class 1 with no TI assigned for transportation. The 14-ton cylinders, although not certified for transport with enrichments greater than 1 wt % because they have no approved overpack, can be used in on-site operations for enrichments greater than 1 wt %. The maximum 235 U enrichments for these cylinders are 5.0 wt % for the 2 1/2-ton cylinder and 4.5 wt % for the 10- and 14-ton cylinders. This work reviews the suitability for reclassification of the 2 1/2-ton UF 6 packages as Fissile Class 1 with a maximum 235 U enrichment of 5 wt %. Additionally, the 10- and 14-ton cylinders are reviewed to address a change in maximum 235 U enrichment from 4.5 to 5 wt %. Based on this evaluation, the 2 1/2-ton UF 6 cylinders meet the 10 CFR.71 criteria for Fissile Class 1 packages, and no TI is needed for criticality safety purposes; however, a TI may be required based on radiation from the packages. Similarly, the 10- and 14-ton UF 6 packages appear acceptable for a maximum enrichment rating change to 5 wt % 235 U. 11 refs., 13 figs., 7 tabs

  3. Calculation of thermal stress condition in long metal cylinder under heating by continuous laser radiation

    International Nuclear Information System (INIS)

    Uglov, A.A.; Uglov, S.A.; Kulik, A.N.

    1997-01-01

    The method of determination of temperature field and unduced thermal stresses in long metallic cylinder under its heating by cw-laser normally distributed heat flux is offered. The graphically presented results of calculation show the stress maximum is placed behind of center of laser heat sport along its movement line on the cylinder surface

  4. Force Control for a Pneumatic Cylinder Using Generalized Predictive Controller Approach

    OpenAIRE

    Mohd Faudzi, Ahmad ’Athif; Mustafa, Nu’man Din; Osman, Khairuddin

    2014-01-01

    Pneumatic cylinder is a well-known device because of its high power to weight ratio, easy use, and environmental safety. Pneumatic cylinder uses air as its power source and converts it to a possible movement such as linear and rotary movement. In order to control the pneumatic cylinder, controller algorithm is needed to control the on-off solenoid valve with encoder and pressure sensor as the feedback inputs. In this paper, generalized predictive controller (GPC) is proposed as the control st...

  5. Cooling Characteristics of the V-1650-7 Engine. II - Effect of Coolant Conditions on Cylinder Temperatures and Heat Rejection at Several Engine Powers

    Science.gov (United States)

    Povolny, John H.; Bogdan, Louis J.; Chelko, Louis J.

    1947-01-01

    An investigation has been conducted on a V-1650-7 engine to determine the cylinder temperatures and the coolant and oil heat rejections over a range of coolant flows (50 to 200 gal/min) and oil inlet temperatures (160 to 2150 F) for two values of coolant outlet temperature (250 deg and 275 F) at each of four power conditions ranging from approximately 1100 to 2000 brake horsepower. Data were obtained for several values of block-outlet pressure at each of the two coolant outlet temperatures. A mixture of 30 percent by volume of ethylene glycol and 70-percent water was used as the coolant. The effect of varying coolant flow, coolant outlet temperature, and coolant outlet pressure over the ranges investigated on cylinder-head temperatures was small (0 deg to 25 F) whereas the effect of increasing the engine power condition from ll00 to 2000 brake horsepower was large (maximum head-temperature increase, 110 F).

  6. Cylinder with differential piston for mass measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bordeaşu, I.; Bălăşoiu, V. [Universitatea Politehnica din Timişoara, Timosoara (Romania); Hadă, A. [UniversitateaPolitehnicaBucureşti, Bucureşti (Romania); Popoviciu, M. [Academy of Romanian ScientistsTimişoara Branch (Romania)

    2007-07-01

    The paper presents a cylinder with differential piston, adapted for measuring the weight of fixed objects such as: fuel tanks (regardless of their capacity), bunkers and silos for all kind of materials, or mobile objects such as: automobiles, trucks, locomotives and railway cars. Although, the cylinder with differential piston is used on a large scale in hydraulic drive or hydraulic control circuits, till now it was not used as constituent part for weight measurements devices. The novelty of the present paper is precisely the use of the device for such purposes. Based on a computation algorithm, the paper presents the general design (assembly), of the device used for weighing important masses (1…. 100 tones). The fundamental idea consist in the fact that, a mass over 10 tones may be weighted with a helicoidally spring subjected to an axial force between 0 and 3000 N, with a deflection of about 30 mm. Simultaneously with the mechanical part, the electronic recording system is also described. The great advantage of the presented device consist in the fact that it can be used in heavy polluted atmosphere or difficult topographic conditions as a result of both the small dimensions and the protection systems adopted. Keywords: cylinder hydraulic with differential piston, hydrostatic pressure, measuring devices.

  7. Flow and flow-induced vibration of a square array of cylinders in steady currents

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Ming [School of Computing, Engineering and Mathematics, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Cheng, Liang; An, Hongwei; Tong, Feifei, E-mail: m.zhao@uws.edu.au [School of Civil, Environmental and Mining Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

    2015-08-15

    Flow and flow-induced vibration of a square array of cylinders are investigated by two-dimensional numerical simulations. Flow past 36 cylinders in an inline arranged square array and 33 cylinders in a staggered arranged square array is firstly simulated, for Re = 100 and the spacing ratios of L/D = 1.5, 2, 3, 4, 5. Only one vortex street is observed in the wake of the cylinder array when the spacing ratio is 1.5 in the inline arrangement and 1.5 and 2 in the staggered arrangement, indicating that the critical spacing ratio for the single-vortex street mode in the staggered arrangement is higher than that in the inline arrangement. The vortex shedding from the cylinders is suppressed at L/D = 3 for both inline and staggered arrangements. Vortex shedding from each individual cylinder is observed when L/D = 4. Flow-induced vibration of 36 cylinders in an inline square arrangement is studied for a constant Reynolds number of 100, two spacing ratios of 2 and 5, a constant mass ratio of 2.5 and a wide range of reduced velocities. It is found that for a spacing ratio of 2, the vibration of the cylinders in the four downstream columns does not start until the reduced velocity exceeds 4.5. The vibration of the cylinders progresses downstream with increasing reduced velocity. For a spacing ratio of 5, the vibrations of the cylinders in the most upstream column are similar to that of a single cylinder. The vibration amplitudes of the downstream cylinders peak at higher reduced velocities than that of a single cylinder. The maximum possible response amplitudes occur at the most downstream cylinders. (paper)

  8. Performance and combustion analysis of Mahua biodiesel on a single cylinder compression ignition engine using electronic fuel injection system

    Directory of Open Access Journals (Sweden)

    Gunasekaran Anandkumar

    2016-01-01

    Full Text Available In this investigation, experiment is carried out on a 1500 rpm constant speed single cylinder Diesel engine. The test is carried out with Neat diesel, neat biodiesel, and blend B20. The engine considered was run with electronic fuel injection system supported by common rail direct injection to obtain high atomization and effective air utilization inside the combustion chamber. The performance of the engine in terms of break thermal efficiency and brake specific energy consumption was found and compared. The B20 blend shows 1.11% decrease in break thermal efficiency and 3.35% increase in brake specific energy consumption than diesel. The combustion characteristics found are in-cylinder pressure, rate of pressure rise, and heat release rate and compared for peak pressure load to understand the nature of combustion process. For each fuel test run, the maximum peak pressure is observed at part load condition. The rate of change of pressure and heat release rate of diesel is high compared to pure biodiesel and B20 blend. The diffusion combustion is observed to be predominant in case of B100 than B20 and Neat diesel.

  9. Photon compression in cylinders

    International Nuclear Information System (INIS)

    Ensley, D.L.

    1977-01-01

    It has been shown theoretically that intense microwave radiation is absorbed non-classically by a newly enunciated mechanism when interacting with hydrogen plasma. Fields > 1 Mg, lambda > 1 mm are within this regime. The predicted absorption, approximately P/sub rf/v/sub theta/sup e/, has not yet been experimentally confirmed. The applications of such a coupling are many. If microwave bursts approximately > 5 x 10 14 watts, 5 ns can be generated, the net generation of power from pellet fusion as well as various military applications becomes feasible. The purpose, then, for considering gas-gun photon compression is to obtain the above experimental capability by converting the gas kinetic energy directly into microwave form. Energies of >10 5 joules cm -2 and powers of >10 13 watts cm -2 are potentially available for photon interaction experiments using presently available technology. The following topics are discussed: microwave modes in a finite cylinder, injection, compression, switchout operation, and system performance parameter scaling

  10. 40 CFR 1042.140 - Maximum engine power, displacement, power density, and maximum in-use engine speed.

    Science.gov (United States)

    2010-07-01

    ... cylinders having an internal diameter of 13.0 cm and a 15.5 cm stroke length, the rounded displacement would... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Maximum engine power, displacement... Maximum engine power, displacement, power density, and maximum in-use engine speed. This section describes...

  11. Cracking investigation of Monju emergency generator C unit cylinder liner. Cylinder liner soundness confirmation by a fall cause of the materials strength of the cylinder liner and the supersonic wave speed

    International Nuclear Information System (INIS)

    Kobayashi, Takanori; Sakon, Miyoji; Takada, Osamu; Hatori, Masakazu; Sakamoto, Tsutomu; Sato, Toshiyuki; Kazama, Akihito; Ishizawa, Yoshihiro; Igawa, Katsuhisa; Nakae, Hideo

    2012-02-01

    I confirmed a leak of the effluent gas from cylinder part during a load examination after the check of the emergency generator C unit on December 28, 2010 of the facilities check average and confirmed crack in No.8 cylinder liner part. As a result, because it was not performed oil pressure management properly without attaching an oil pressure gauge when I removed cylinder liner about the cause, crack occurred by having been able to write excessive stress for the cylinder liner and reached damage. By a process of this investigation, a fall of the materials strength of some cylinder liner was confirmed, but because a lead ingredient got mixed with materials by a casting process at the time of the production of the cylinder liner, as for this, Widmannstaetten graphite occurred, and it became clear that materials strength fell. In addition, I performed inspection by the supersonic wave velocity measurement as technique to distinguish this Widmannstaetten graphite easily and confirmed that I was effective. Because this report was the knowledge that there were little inspection contents which modified soundness confirmation technique of the cylinder liner with the possibility of materials strength fall of the cylinder liner by the Widmannstaetten graphite outbreak and the mixture of lead for a report example in the field of cast iron, I gathered it in this report. (author)

  12. Influence of plane bed on the force exerted on a cylinder oscillating in still water

    Energy Technology Data Exchange (ETDEWEB)

    Naeeni, S.T.O. [Tehran Univ., Dept. of Civil Engineering, Tehran (Iran); Narayanan, R. [Universiti Teknologi Malaysia, Faculty of Civil Engineering, Johor Bahru (Malaysia)

    2005-12-01

    The wall pressure field on a cylinder oscillating over a plane bed in still water is reported in this paper. Two gaps between the cylinder and the bed were considered. Pressures on the periphery of the cylinder were measured by a transducer and were found to be essentially repeatable from one cycle to the next. The forces determined from the pressure profiles compare well with those measured directly by a force transducer except significantly at Keulegan-Carpenter number of 15.0. The importance of the plane bed when it is stationary or moving with the cylinder is examined. The significance of the roughness of the bed with respect to the oscillatory forces exerted on the cylinder is also assessed. (Author)

  13. Study of elastoplastic deformations self-fretting of flat cylinders by mandrelling

    International Nuclear Information System (INIS)

    Caron, Roger

    1974-04-01

    An application of the theory of thick tubes to the special case of flat cylinders which have been self-fretted by mandrelling, is presented. The following materials were used: 1 - a soft steel, XC 18 F, considered to be perfectly elastoplastic; 2 - an alloyed steel, 35 NCD 16, designated consolidable. In the first case, the slip trajectories observed on the polished cylinder surface enabled the plastic deformation region to be defined. It was found, in particular, that the average value of the mean boundary radius at the maximum pressure differs very little from that determined using basic formulas. In the second case, the plastic deformations uniformly affect the internal layers, and privileged trajectories do not exist in this region. On the other hand, the ε θ and ε r expansion curves (from deformation measurements), are continuous from the inner radius to the outer radius; the boundary radius was thus localized from considerations of its correspondence with the ε θ -ε r (shearing deformation) at the elastic limit of the material. This characteristic was determined from measurements made using a test piece provided for this purpose. The radii obtained with this method agree with the theoretical radii over only 4/5 of the total deformation, the uncertainty region being taken into consideration. The maximum value of this parameter was determined in such a way as to obtain a return to a completely elastic rest position. (author) [fr

  14. Effect of intake swirl on the performance of single cylinder direct injection diesel engine

    Science.gov (United States)

    Sharma, Vinod Kumar; Mohan, Man; Mouli, Chandra

    2017-11-01

    In the present work, the effect of inlet manifold geometry and swirl intensity on the direct injection (DI) diesel engine performance was investigated experimentally. Modifications in inlet manifold geometry have been suggested to achieve optimized swirl for the better mixing of fuel with air. The intake swirl intensities of modified cylinder head were measured in swirl test rig at different valve lifts. Later, the overall performance of 435 CC DI diesel engine was measured using modified cylinder head. In addition, the performance of engine was compared for both modified and old cylinder head. For same operating conditions, the brake power and brake specific fuel consumption was improved by 6% and 7% respectively with modified cylinder head compared to old cylinder head. The maximum brake power of 9 HP was achieved for modified cylinder head. The results revealed that the intake swirl has great influence on engine performance.

  15. Experiments of flow-induced in-line oscillation of a circular cylinder in a water tunnel. 2. Influence of the aspect ratio of a cantilevered circular cylinder

    International Nuclear Information System (INIS)

    Nakamura, Akira; Okajima, Atsushi; Kosugi, Takashi

    2001-01-01

    The flow-induced in-line oscillation of a cantilevered circular cylinder was experimentally studied through free-oscillation tests in a water tunnel. The response displacement amplitude at a circular cylinder tip was measured at reduced velocity from 1.0 to 4.0. A cantilevered cylinder was supported by a plate spring mounted on the water tunnel wall. The cylinder aspect ratio was varied from 5 to 21 to investigate the effect of aspect ratio on the response displacement. It is found that cylinders with aspect ratios of 5 and 10 have one excitation region, while cylinders with aspect ratios of 14 and 21 have two excitation regions. The aspect ratio, therefore, affects the amplitude of the excitation regions. The influence of end-effect was also investigated using cylinders with an end plate attached to the free end. Since the cylinders with an end plate show two excitation regions, even at an aspect ratio of 5, the flow around the free end of a cantilevered cylinder causes the end-effect. The mechanism of vibration was investigated using a cylinder with a splitter plate in wake to prevent alternate vortices. The amplitude is greater than those of a normal cylinder without a splitter plate, especially at V r =2.3 to 3.0, where a cylinder with an end plate shows the second excitation region. In order words, the alternate vortices suppress the amplitude in this range. The maximum amplitude of each excitation region decreases in proportion to C n and the amplitude of the first excitation is more sensitive to C n . (author)

  16. Vortex shedding control of circular cylinder by perforated shroud in deep water

    Directory of Open Access Journals (Sweden)

    Ozkan Gokturk M.

    2017-01-01

    Full Text Available The aim of the present study is to control the vortex shedding downstream of a circular cylinder (inner cylinder by the existence of outer perforated cylinder concentrically located around the inner cylinder in deep water. The flow characteristics downstream of concentrically placed coupled cylinders were investigated quantitatively by the Particle Image Velocimetry (PIV technique. Diameter of the outer perforated cylinder and inner cylinder were kept constant as Do=100 mm and Di=50 mm. The depth-averaged free-stream velocity was also kept constant as U=100 mm/s which corresponded to the Reynolds number of ReDo=10,000 based on the outer cylinder diameter. Experiments were conducted for six porosities (β = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 in order to show the effect of these parameters on the flow control. Maximum values of both Reynolds shear stress, and turbulence kinetic energy, significantly decreased with the existence of outer perforated cylinder and also, the location of peak magnitudes of turbulence statistics occurred at locations further downstream compared to the bare cylinder case. The most effective control was revealed for the porosity of β=0.7.

  17. Vortex shedding control of circular cylinder by perforated shroud in deep water

    Science.gov (United States)

    Ozkan, Gokturk M.; Durhasan, Tahir; Pinar, Engin; Aksoy, Muhammed M.; Akilli, Huseyin; Sahin, Beşir

    The aim of the present study is to control the vortex shedding downstream of a circular cylinder (inner cylinder) by the existence of outer perforated cylinder concentrically located around the inner cylinder in deep water. The flow characteristics downstream of concentrically placed coupled cylinders were investigated quantitatively by the Particle Image Velocimetry (PIV) technique. Diameter of the outer perforated cylinder and inner cylinder were kept constant as Do=100 mm and Di=50 mm. The depth-averaged free-stream velocity was also kept constant as U=100 mm/s which corresponded to the Reynolds number of ReDo=10,000 based on the outer cylinder diameter. Experiments were conducted for six porosities (β = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) in order to show the effect of these parameters on the flow control. Maximum values of both Reynolds shear stress, and turbulence kinetic energy, significantly decreased with the existence of outer perforated cylinder and also, the location of peak magnitudes of turbulence statistics occurred at locations further downstream compared to the bare cylinder case. The most effective control was revealed for the porosity of β=0.7.

  18. Lift and Drag on Cylinder of Octagonal Cross-Section in a Turbulent Stream

    Directory of Open Access Journals (Sweden)

    Md. Jomir Hossain

    2013-12-01

    Full Text Available An experimental investigation of surface static pressure distributions on octagonal cylinder in uniform and turbulent flows was carried out. The study was performed on both the single cylinder and the group of two cylinders, two cylinders were used, one was at the upstream side, and the other was at the downstream side of the flow. They were placed centrally along the flow direction. The inter-spacing space between the two cylinders was varied at 1D, 2D, 3D, 4D, 5D, 6D, 7D and 8D, where D is the width of the cylinder across the flow direction. The pressure coefficients were calculated from the measured values of the surface static pressure distribution on the cylinder. Then the drag and lift coefficients were obtained from the pressure coefficients by the numerical integration method. It was observed that at various angles of attack, the values of the lift coefficients and drag coefficients were insignificant compared to those for a sharp-edged square cylinder. The strength of the vortex shedding was shown to be reduced as the intensity of the incident turbulence was increased. Measurements of drag at various angles of attack (0° to 40° showed that with increase in turbulence level the minimum drag occurred at smaller values of angle of attack.

  19. Background-oriented schlieren imaging of flow around a circular cylinder at low Mach numbers

    Science.gov (United States)

    Stadler, Hannes; Bauknecht, André; Siegrist, Silvan; Flesch, Robert; Wolf, C. Christian; van Hinsberg, Nils; Jacobs, Markus

    2017-09-01

    The background-oriented schlieren (BOS) imaging method has, for the first time, been applied in the investigation of the flow around a circular cylinder at low Mach numbers (Msuccessive imaging at incremental angular positions around the cylinder. This density distribution has been found to agree well with the pressure measurements and with potential theory where appropriate.

  20. New system for measuring and controlling the maximum pressing pressure in the holes of the mould: ISOPRESS; Nuevo sistema para la medida y control de la presion maxima de prensado en los alveolos del molde: ISOPRESS

    Energy Technology Data Exchange (ETDEWEB)

    Poyatos, A.; Bonaque, R.; Mallol, G.; Boix, J.

    2012-07-01

    The organization MACER, in collaboration with the Institute of Ceramic Technology, has developed the system ISOPRESS, an integrated control device that permits to equal automatically the maximum pressure applied on the powder contained in each of the holes of the mould. This system consists of a set of pressure transducers which are located in the isostatic punches of the mould itself. With them it is possible to register in real-time the evolution of the measured pressure of the oil contained in the compensation chamber of each punch. All the transducers are connected to a data acquisition system which transfers the pressure values to a PC which performs the signal processing to obtain the pressure maximum value reached during a pressing cycle, in each one of the holes. The system is completed with a control software especially developed, that permits to regulate individually the height of the first fall of each inferior punch to guarantee the uniformity of the pressure applied in all the holes. ISOPRESS, by assuring the constancy of the bulk density of all the pieces processed, guarantees a unique piece size and minimize production problems associated to the variability of the bulk density of the pieces. (Author)

  1. Estudio de la variación del acabado superficial del cilindro en función de la presión de diseño en los hidromotores de pistones radiales. // Cylinder superficial finish variation study in function of design pressure in radial pistons hydromotors.

    Directory of Open Access Journals (Sweden)

    G. Morejón Vizcaino

    2003-01-01

    Full Text Available En este artículo se realiza un estudio teórico de la tendencia del comportamiento de la rugosidad superficial en los cilindrosde los motores hidráulicos tipo estrella para mantener constante la eficiencia volumétrica ante un incremento de la presiónde trabajo. Con el objetivo de determinar la tendencia de como influye la presión de diseño en la tecnología de construccióndel motor. La tendencia moderna es construir hidromotores con presión de diseño elevada para alcanzar altas densidades depotencia, para este empeño se utiliza la ley de Poiseuille para establecer el modelo de fuga entre cilindro y pistón. Elmodelo de la holgura se establece a partir de suponer lineal el comportamiento descrito en la literatura consultada, seobtienen resultados de rugosidad del cilindro contra presión para mantener la eficiencia volumétrica constante. Quedademostrado que el ensayo, para inferir los valores necesarios para el cálculo a realizar, se realiza sobre un cilindro similar alcilindro del motor.Palabras claves: Eficiencia volumétrica, algoritmo, motores hidráulicos, acabado superficial, fugas.____________________________________________________________________________Abstract.In this article is carried out a theoretical study of the tendency of superficial ruggedness behavior in cylinders of hydraulicmotors (star type to maintain constant the volumetric efficiency when is applied an increment of working pressure withthe objective of determining the tendency of how the design pressure influences in the motor construction technology.Since the modern tendency is to build hydromotors with risen design pressure in order to reach high power densities, forthis engagement the law of Poiseuille is used to establish the fugue pattern between cylinder and piston.The looseness model is stated starting from supposing lineal the behavior described in the consulted literature, results of thecylinder ruggedness against pressure are obtained to maintain

  2. Boundary value problems of the circular cylinders in the strain-gradient theory of linear elasticity

    International Nuclear Information System (INIS)

    Kao, B.G.

    1979-11-01

    Three boundary value problems in the strain-gradient theory of linear elasticity are solved for circular cylinders. They are the twisting of circular cylinder, uniformly pressuring of concentric circular cylinder, and pure-bending of simply connected cylinder. The comparisons of these solutions with the solutions in classical elasticity and in couple-stress theory reveal the differences in the stress fields as well as the apparent stress fields due to the influences of the strain-gradient. These aspects of the strain-gradient theory could be important in modeling the failure behavior of structural materials

  3. Dynamic Measurement of Extra Long Stroke Cylinder in the Pneumatic System

    International Nuclear Information System (INIS)

    Chang Ho; Lan Chouwei; Chen, L-C

    2006-01-01

    This paper sets up the measure and control system of the dynamic characteristics of the extra long stroke cylinder. In the different types of the control conditions (e.g. different control law, operating pressure and direct control valves), using the measure and control system to measure the relation between the pressure and the velocity of the motion of the long stroke cylinder and to observe the stick slip phenomenon of the motion of the long stroke cylinder. In the innovate measurement system, two pressure sensors are set on the long stroke cylinder to measure the difference of the pressure between the inlet and the exhaust of the long stroke cylinder. In additions, a draw line encoder is set on the system to measure the position and the velocity of the motion of the long stroke cylinder. The measuring data of the measure system is transferred to the computer via A/D interface card and counter card, and Home-made program of Haptic Interface Device is used to control the system, saving the data of the motion of the long stroke cylinder. The system uses different types of direction control valve to control the motion of the long stroke cylinder and compares the difference of the motion of the long stroke cylinder. The results show that the motion of the cylinder that pauses in the middle of the cylinder stroke and causes the stick slip phenomenon is more violent than the stick slip phenomenon in other position. When the length of the pause time reaches the some range, the acceleration of the motion of the cylinder will be rised substantially. This paper not only focuses on the testing method of the dynamic characteristics of the motion of the long stroke cylinder, but also includes the analysis of the dynamic characteristics of the motion of the long stroke cylinder. It provides the data of the dynamic characteristics of the motion of the long stroke cylinder to improve and design the pneumatic system of the long stroke cylinder

  4. Experimental research of the yielding behavior of a graphite cylinder subjected to line loading

    International Nuclear Information System (INIS)

    Liu Hetong; Ma Qinwei; Ma Shaopeng; Wang Hongtao

    2014-01-01

    The graphite material cylinders are widely used in High-temperature gas-cooled reactor as connecting components. For engineering design, the deformation behavior, especially the yielding process of the graphite cylinder should be investigated in order to evaluate the carrying capacity of the cylinder. The yielding formation and propagation of a graphite cylinder subjected to line loading, which corresponds to the global behavior of the structure, was experimentally studied and evaluated by measuring the strain fields on the end of the cylinder using Digital Image Correlation. The global behavior of the structure is expressed by a relationship between the average stress (load divided by contact area) and the equivalent strain (ratio of half width of contact area to radius of the cylinder), the contact area was measured by identifying the color area of the pressure film in a new experiment which graphite component is loaded and unloaded continuously. A correspondence between the yielding state and the nonlinearity of the global behavior was constructed, as loading was increased, the cylinder was found to first yield at a specific point after which a yielding core formed and propagated. Before the yielding core propagated to the surface of the cylinder, the global behavior of the structure remained linear. After the yielding core propagated to the surface of the cylinder, the global behavior became nonlinear. The correspondence constructed in the paper will be helpful to understand the failure process and to evaluate the carrying capacity of a graphite cylinder subjected to line loading in reactors. (author)

  5. 75 FR 12713 - Airworthiness Directives; AVOX Systems and B/E Aerospace Oxygen Cylinders as Installed on Various...

    Science.gov (United States)

    2010-03-17

    ... proposed AD was prompted by the reported rupture of a high-pressure gaseous oxygen cylinder, which had...) This AD was prompted by the reported rupture of a high- pressure gaseous oxygen cylinder, which had... necessary oxygen supply for the flightcrew, and injury to cabin occupants or other support personnel. DATES...

  6. Photoelastic Analysis of Cracked Thick Walled Cylinders

    Science.gov (United States)

    Pastramă, Ştefan Dan

    2017-12-01

    In this paper, the experimental determination of the stress intensity factor in thick walled cylinders subject to uniform internal pressure and having longitudinal non-penetrating cracks is presented. Photoelastic measurements were used together with the expressions of the stress field near the crack tip for Mode I crack extension and a specific methodology for stress intensity factor determination. Two types of longitudinal cracks - internal and external - were considered. Four plane models were manufactured and analyzed in a plane polariscope at different values of the applied internal pressure. The values of the normalized stress intensity factor were calculated and the results were compared to those reported by other authors. A good accuracy was noticed, showing the reliability of the experimental procedure.

  7. Assembly for electrical conductivity measurements in the piston cylinder device

    Science.gov (United States)

    Watson, Heather Christine [Dublin, CA; Roberts, Jeffrey James [Livermore, CA

    2012-06-05

    An assembly apparatus for measurement of electrical conductivity or other properties of a sample in a piston cylinder device wherein pressure and heat are applied to the sample by the piston cylinder device. The assembly apparatus includes a body, a first electrode in the body, the first electrode operatively connected to the sample, a first electrical conductor connected to the first electrode, a washer constructed of a hard conducting material, the washer surrounding the first electrical conductor in the body, a second electrode in the body, the second electrode operatively connected to the sample, and a second electrical conductor connected to the second electrode.

  8. Effects of fire exposure on integrity of UF6 shipping cylinders

    International Nuclear Information System (INIS)

    Barlow, C.R.; Ziehlke, K.T.; Pryor, W.A.

    1985-01-01

    Two 2-1/2-ton steel cylinders for the transport of uranium hexafluoride within the United States nuclear fuel enrichment cycle were involved in a warehouse fire where portions of the cylinders were estimated to have reached a temperature of 1600 0 F (870 0 C). The cylinders were empty at the time of the fire and therefore were not in protective overpacks in which full product cylinders are handled while in transit. Hydrostatic tests to failure showed that the integrity of the cylinders was not degraded by exposure to the temperatures generated by the fire. They withstood test pressures in excess of 10 times the design pressure, and showed a volume expansion of 30% above the original capacity before rupture in a completely ductile fashion. Reference CAPE-323. 9 figs

  9. Mechanism of drag reduction for circular cylinders with patterned surface

    International Nuclear Information System (INIS)

    Butt, U.; Jehring, L.; Egbers, C.

    2014-01-01

    Highlights: • Reduced drag of patterned cylinders over a wide range of Re numbers. • Hexagonal patterns cannot be characterized as roughness structures. • Hexagonal bumps affect the flow like spherical dimples of smaller k/d ratio do. • Main separation is delayed caused by a partial separation. • Angle of a separation line is not constant over the length of cylinder. -- Abstract: In this paper, the flow over cylinders with a patterned surface (k/d = 1.98 × 10 −2 ) is investigated in a subsonic wind tunnel over Reynolds numbers ranging from 3.14 × 10 4 to 2.77 × 10 5 by measuring drag, flow visualization and measuring velocity profiles above the surface of the cylinders, to observe the effect of hexagonal patterns on the flow of air. These patterns can also be referred as hexagonal dimples or bumps depending on their configuration. The investigations revealed that a patterned cylinder with patterns pressed outwards has a drag coefficient of about 0.65 times of a smooth one. Flow visualization techniques including surface oil-film technique and velocity profile measurement were employed to elucidate this effect, and hence present the mechanism of drag reduction. The measurement of velocity profiles using hot-wire anemometry above the surface reveal that a hexagonal bump cause local separation generating large turbulence intensity along the separating shear layer. Due to this increased turbulence, the flow reattaches to the surface with higher momentum and become able to withstand the pressure gradient delaying the main separation significantly. Besides that, the separation does not appear to occur in a straight line along the length of the cylinder as in case of most passive drag control methods, but follow exactly the hexagonal patterns forming a wave with its crest at 115° and trough at 110°, in contrast to the laminar separation line at 85° for a smooth cylinder

  10. Active aerodynamic drag reduction on morphable cylinders

    Science.gov (United States)

    Guttag, M.; Reis, P. M.

    2017-12-01

    We study a mechanism for active aerodynamic drag reduction on morphable grooved cylinders, whose topography can be modified pneumatically. Our design is inspired by the morphology of the Saguaro cactus (Carnegiea gigantea), which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. Our analog experimental samples comprise a spoked rigid skeleton with axial cavities, covered by a stretched elastomeric film. Decreasing the inner pressure of the sample produces axial grooves, whose depth can be accurately varied, on demand. First, we characterize the relation between groove depth and pneumatic loading through a combination of precision mechanical experiments and finite element simulations. Second, wind tunnel tests are used to measure the aerodynamic drag coefficient (as a function of Reynolds number) of the grooved samples, with different levels of periodicity and groove depths. We focus specifically on the drag crisis and systematically measure the associated minimum drag coefficient and the critical Reynolds number at which it occurs. The results are in agreement with the classic literature of rough cylinders, albeit with an unprecedented level of precision and resolution in varying topography using a single sample. Finally, we leverage the morphable nature of our system to dynamically reduce drag for varying aerodynamic loading conditions. We demonstrate that actively controlling the groove depth yields a drag coefficient that decreases monotonically with Reynolds number and is significantly lower than the fixed sample counterparts. These findings open the possibility for the drag reduction of grooved cylinders to be operated over a wide range of flow conditions.

  11. Literature review and experimental results for a cylinder with perforations and protrusions at high Reynolds numbers

    Science.gov (United States)

    Jones, G. S.; Horvath, T. J.; Stainback, P. C.; Beasley, W. D.; Mcghee, R. J.

    1987-01-01

    The NASA Langley Low Turbulence Pressure Tunnel has been used to conduct an experimental study of the flow around a series of circular cylinders; the models used consisted of a baseline, smooth cylinder together with a cylinder that could be reconfigured with six different arrangements of two types of surface irregularity. Mean lift and drag forces were measured on all seven model configurations, and correlations were made between unsteady pressure in the wake region and fluctuating lift forces, in order to identify coherent structures.

  12. The numerical simulation of the WWER-440/V-213 reactor pressure vessel internals response to maximum hypothetical large break loss of coolant accident

    International Nuclear Information System (INIS)

    Hermansky, P.; Krajcovic, M.

    2012-01-01

    The reactor internals are designed to ensure cooling of the fuel, to ensure the movement of emergency control assemblies under all operating conditions including accidents and facilitate removal of the fuel and of the internals following an accident This paper presents results of the numerical simulation of the WWER-440/V213 reactor vessel internals dynamic response to maximum hypothetical Large-Break Loss of Coolant Accident. The purpose of this analysis is to determine the reactor vessel internals response due to rapid depressurization and to prove no such deformations occur in the reactor vessel internals which would prevent timely and proper activation of the emergency control assemblies. (Authors)

  13. Surface flaw in a thermally shocked hollow cylinder

    International Nuclear Information System (INIS)

    Kobayashi, A.S.; Emery, A.F.; Polvanich, N.; Love, W.J.

    1975-01-01

    The objective of this paper is to illustrate a procedure for estimating the stress intensity factors of a semi-elliptical crack located in the inner or outer surface of a thermally shocked hollow cylinder. The first step in this procedure is to estimate the transient thermal elastic stresses induced by sudden cooling of an uncracked cylinder by numerically evaluating standard heat transfer and thermal stress formulae. The stresses at the location of the crack surface in the uncracked cylinder are eliminated by the method of superposition in order to obtain a stress free crack surface. The stress intensity factors are then determined by a judicious use of two sets of solutions, one set involving stress intensity factors for a semi-elliptical crack in a flat plate and subjected to a polynomial distribution of pressure loading, and another set involving single-edge notched plates with prescribed edge-displacements and single-edge internally or externally notched cylinders with thermal shock loading. The former solutions are determined by the alternating technique in three-dimensional fracture mechanics with a fourth order polynomial pressure distribution on the crack surface where both the front and back surface effects are accounted for. The latter solutions involve two-dimensional finite element solutions of single-edge notched plates with prescribed edge-displacements and single-edge notched cylinders with thermal shock loading. By comparing these two two-dimensional solutions, an estimate of the effect of the cylindrical curvature on an edge-cracked plate is obtained. The combination of these two sets of solutions thus yields an estimate of the stress intensity factor in an internal and external semi-elliptical crack in a thermally shocked cylinder

  14. Self-contained high-pressure chambers for study on the Moessbauer effect at low temperatures

    International Nuclear Information System (INIS)

    Stepanov, G.N.

    1980-01-01

    Designs of two high-pressure chambers intended for studying the Moessbauer effect at low temperatures are described. The high-pressure chamber of the Bridgman anvil type is made of non magnetic materials and intended for operation at helium temperatures. The chamber employs a superconducting pressure gage. A sample and superconducting pressure gage are surrounded with a liquid medium of a high pressure at a room temperature. Measurements of the pressure were taken during heating the chamber in the vapours of liquid helium according to the known dependence of the lead superconducting transition temperature on pressure. The other high-pressure chamber of the piston-to-cylinder type can be used to study the Moessbauer effect at temperatures ranging from 4 to 300 K. Pressure in the chamber is measured by means of the superconducting pressure gage. The maximum pressure obtained in the chamber constitutes 25 kbar

  15. Drag reduction and thrust generation by tangential surface motion in flow past a cylinder

    Science.gov (United States)

    Mao, Xuerui; Pearson, Emily

    2018-03-01

    Sensitivity of drag to tangential surface motion is calculated in flow past a circular cylinder in both two- and three-dimensional conditions at Reynolds number Re ≤ 1000 . The magnitude of the sensitivity maximises in the region slightly upstream of the separation points where the contour lines of spanwise vorticity are normal to the cylinder surface. A control to reduce drag can be obtained by (negatively) scaling the sensitivity. The high correlation of sensitivities of controlled and uncontrolled flow indicates that the scaled sensitivity is a good approximation of the nonlinear optimal control. It is validated through direct numerical simulations that the linear range of the steady control is much higher than the unsteady control, which synchronises the vortex shedding and induces lock-in effects. The steady control injects angular momentum into the separating boundary layer, stabilises the flow and increases the base pressure significantly. At Re=100 , when the maximum tangential motion reaches 50% of the free-stream velocity, the vortex shedding, boundary-layer separation and recirculation bubbles are eliminated and 32% of the drag is reduced. When the maximum tangential motion reaches 2.5 times of the free-stream velocity, thrust is generated and the power savings ratio, defined as the ratio of the reduced drag power to the control input power, reaches 19.6. The mechanism of drag reduction is attributed to the change of the radial gradient of spanwise vorticity (partial r \\hat{ζ } ) and the subsequent accelerated pressure recovery from the uncontrolled separation points to the rear stagnation point.

  16. Numerical Study of Mixed Convection of Nanofluid in a Concentric Annulus with Rotating Inner Cylinder

    Directory of Open Access Journals (Sweden)

    G. A. Sheikhzadeh

    2013-01-01

    Full Text Available In this work, the steady and laminar mixed convection of nanofluid in horizontal concentric annulus withrotating inner cylinder is investigated numerically. The inner and outer cylinders are kept at constanttemperature Ti and To respectively, where Ti>To. The annular space is filled with Alumina-water nanofluid.The governing equations with the corresponded boundary conditions in the polar coordinate are discretizedusing the finite volume method where pressure-velocity coupling is done by the SIMPLER algorithm.Numerical results have been obtained for Rayleigh number ranging from 102 to 105, Reynolds number from 1 to 300 and nanoparticles volume fraction from 0.01 to 0.06. The effects of the Reynolds and Rayleigh numbers, average diameter of nanoparticles and the volume fraction of the nanoparticles on the fluid flow and heat transfer inside the annuli are investigated. According to the results, the average Nusselt number decreases with increasing the Reynolds number. However, the average Nusselt number increases by increasing the Rayleigh number. Moreover, the maximum average Nusselt number occurs for an optimal nanoparticle volume fraction except situations that heat conduction predominates over the heat convection. In these conditions the average Nusselt number is close to unity.

  17. Numerical Characterisation of Active Drag and Lift Control for a Circular Cylinder in Cross-Flow

    Directory of Open Access Journals (Sweden)

    Philip McDonald

    2017-11-01

    Full Text Available Synthetic jet actuators have shown promise to control drag and lift for a bluff body in cross-flow. Using unsteady RANS CFD modelling, a significant modification of the drag coefficient for a circular cylinder in cross-flow at R e = 3900 is achieved by varying the actuation frequency. The variation in actuation frequency corresponds to a range in Stokes number of 2.4 < S t o < 6.4. The trends in drag coefficient modification largely agree with the findings of past publications, achieving a maximum drag reduction at S t o = 4.9 for a fixed jet Reynolds number of the synthetic jet of R e U ¯ o = 12. A decrease in the adverse pressure gradient near the jet orifice correlated with a momentum increase in the viscous sublayer and stronger vortical structures at the rear of the cylinder. In these same conditions, a decrease in turbulence intensity was observed in the far field wake, which is a relevant finding in the context of wind and tidal turbine arrays.

  18. Natural convective heat transfer from square cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Novomestský, Marcel, E-mail: marcel.novomestsky@fstroj.uniza.sk; Smatanová, Helena, E-mail: helena.smatanova@fstroj.uniza.sk; Kapjor, Andrej, E-mail: andrej.kapjor@fstroj.uniza.sk [University of Žilina, Faculty of Mechanical Engineering, Department of Power Engineering, Univerzitná 1, 010 26 Žilina (Slovakia)

    2016-06-30

    This article is concerned with natural convective heat transfer from square cylinder mounted on a plane adiabatic base, the cylinders having an exposed cylinder surface according to different horizontal angle. The cylinder receives heat from a radiating heater which results in a buoyant flow. There are many industrial applications, including refrigeration, ventilation and the cooling of electrical components, for which the present study may be applicable.

  19. Large-Eddy Simulation of a High Reynolds Number Flow Around a Cylinder Including Aeroacoustic Predictions

    Science.gov (United States)

    Spyropoulos, Evangelos T.; Holmes, Bayard S.

    1997-01-01

    The dynamic subgrid-scale model is employed in large-eddy simulations of flow over a cylinder at a Reynolds number, based on the diameter of the cylinder, of 90,000. The Centric SPECTRUM(trademark) finite element solver is used for the analysis. The far field sound pressure is calculated from Lighthill-Curle's equation using the computed fluctuating pressure at the surface of the cylinder. The sound pressure level at a location 35 diameters away from the cylinder and at an angle of 90 deg with respect to the wake's downstream axis was found to have a peak value of approximately 110 db. Slightly smaller peak values were predicted at the 60 deg and 120 deg locations. A grid refinement study suggests that the dynamic model demands mesh refinement beyond that used here.

  20. The Present Status of Using Natural Gas Cylinders and Acoustic Emission in Thailand

    Science.gov (United States)

    Jomdecha, C.; Jirarungsatian, C.; Methong, W.; Poopat, B.

    This chapter presents the status of using natural gas cylinders (CNG/NGV) and acoustic emission (AE) in Thailand. During the period from 2006 to 2013, more than 600,000 CNG cylinder units for vehicles were installed and used for transportation, cars, and trucks in Thailand. The number of cylinder units will be tentatively increased in the future due to the increase in gasoline price. Due to the use of high-pressurization equipment in public, the issue of a risk to public safety has been raised. As of this writing, in 2013, the testing standard from the Thai Department of Energy Business recommends inspection every 5 years using effective inspection methods in order to guarantee safe usage of gas cylinders, including the AE method, following ISO 16148. Normally in Thailand, AE is used in research and petrochemical plants as a special technique. The main applications are testing of pressure vessels, aboveground storage tanks, and university research. Few companies are available to conduct AE for testing natural gas cylinders due to the limited safety of the high-pressure operation and AE equipment and a lack of qualified AE personnel. To develop AE techniques, equipment, procedures, and acceptance criteria of natural gas cylinders are the main focus of AE personnel in Thailand. A desired achievement for current development is for natural gas cylinder testing, which can be applied in field tests and supported by a national testing standard.

  1. Design and Analysis of an Experimental Setup for Determining the Burst Strength and Material Properties of Hollow Cylinders

    Science.gov (United States)

    2015-12-01

    pressure hydraulic pump or through application of a compressive force to a piston . These designs essentially cap the ends of the cylinder and require...spiral-wound line connected to a vacuum pump was then taped to the mold cylinder as shown in Figure 23. The entire mold cylinder was then removed...of perforated release ply and breather cloth to absorb excess epoxy. A spiral-wound line connected to a vacuum pump was routed along the edge of the

  2. Label inspection of approximate cylinder based on adverse cylinder panorama

    Science.gov (United States)

    Lin, Jianping; Liao, Qingmin; He, Bei; Shi, Chenbo

    2013-12-01

    This paper presents a machine vision system for automated label inspection, with the goal to reduce labor cost and ensure consistent product quality. Firstly, the images captured from each single-camera are distorted, since the inspection object is approximate cylindrical. Therefore, this paper proposes an algorithm based on adverse cylinder projection, where label images are rectified by distortion compensation. Secondly, to overcome the limited field of viewing for each single-camera, our method novelly combines images of all single-cameras and build a panorama for label inspection. Thirdly, considering the shake of production lines and error of electronic signal, we design the real-time image registration to calculate offsets between the template and inspected images. Experimental results demonstrate that our system is accurate, real-time and can be applied for numerous real- time inspections of approximate cylinders.

  3. Mechanical Cushion Design Influence on Cylinder Dynamics

    DEFF Research Database (Denmark)

    Borghi, Massimo; Milani, Massimo; Conrad, Finn

    2005-01-01

    . experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined......The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow......-rate (and of the correspondent discharging orifice design) on the cushioning characteristics variation is firstly introduced. Then, with respect to the case of the cylindrical cushioning engagement, both the reliability and the limits of the numerical approach are highlighted through a numerical vs...

  4. Lagrangian Visualization and Real-Time Identification of the Vortex Shedding Time in the Wake of a Circular Cylinder

    Science.gov (United States)

    Rockwood, Matthew P.

    on a circular cylinder in crossflow. The acceleration of the Lagrangian saddle occurs simultaneously with a maximum in lift in both numerical cases, and with a minimum in the static pressure at a location slightly upstream of the mean separation location in the numerical cases, as well as the experimental data at a Reynolds number of 19,000. This allows the von Karman vortex shedding time, determined objectively by the acceleration of the Lagrangian saddle away from the circular cylinder, to be detected by a minimum in the static pressure at one location on the cylinder, a quantity that can be measured in real-time using available pressure sensors. These results can be used to place sensors in optimal locations on bluff bodies to inform closed-loop flow control algorithms of the timing of von Karman vortex shedding.

  5. Force Control for a Pneumatic Cylinder Using Generalized Predictive Controller Approach

    Directory of Open Access Journals (Sweden)

    Ahmad ’Athif Mohd Faudzi

    2014-01-01

    Full Text Available Pneumatic cylinder is a well-known device because of its high power to weight ratio, easy use, and environmental safety. Pneumatic cylinder uses air as its power source and converts it to a possible movement such as linear and rotary movement. In order to control the pneumatic cylinder, controller algorithm is needed to control the on-off solenoid valve with encoder and pressure sensor as the feedback inputs. In this paper, generalized predictive controller (GPC is proposed as the control strategy for the pneumatic cylinder force control. To validate and compare the performance, proportional-integral (PI controller is also presented. Both controllers algorithms GPC and PI are developed using existing linear model of the cylinder from previous research. Results are presented in simulation and experimental approach using MATLAB-Simulink as the platform. The results show that the GPC is capable of fast response with low steady state error and percentage overshoot compared to PI.

  6. Reduction of sound transmission across plenum windows by incorporating an array of rigid cylinders

    Science.gov (United States)

    Tang, S. K.

    2018-02-01

    The potential improvement of plenum window noise reduction by installing rigid circular cylinder arrays into the window cavity is investigated numerically using the finite-element method in this study. A two-dimensional approach is adopted. The sound transmission characteristics and propagation within the plenum window are also examined in detail. Results show that the installation of the cylinders in general gives rise to broadband improvement of noise reduction across a plenum window regardless of the direction of sound incidence. Such acoustical performance becomes better when more cylinder columns are installed, but it is suggested that the number of cylinder rows should not exceed two. Results also show that the cylinder positions relative to the nodal/anti-nodal planes of the acoustic modes are crucial in the noise reduction enhancement mechanisms. Noise reduction can further be enhanced by staggering the cylinder rows, such that each cylinder row supports the development of a different acoustic mode. For the simple cylinder arrangements considered in this study, the traffic noise reduction enhancement observed in this study can be as high as 4-5 dB, which is already comparable to or higher than the maximum achieved by installing sound absorption into a plenum window.

  7. Use of Directional Spectra for Detection of Engine Cylinder Power Fault

    Directory of Open Access Journals (Sweden)

    Chong-Won Lee

    1997-01-01

    Full Text Available A diagnostic method, which uses the two-sided directional power spectra of complex-valued engine vibration signals, is presented and tested with four-cylinder compression and spark ignition engines for the diagnosis of cylinder power faults. As spectral estimators, the maximum likelihood and FFT methods are compared, and the multi-layer neural network is employed for pattern recognition. Experimental results show that the success rate for identifying the misfired cylinder is much higher with the use of two-sided directional power spectra than conventional one-sided power spectra.

  8. Non-Newtonian flow between concentric cylinders calculated from thermophysical properties obtained from simulations

    International Nuclear Information System (INIS)

    Narayan, A.P.; Rainwater, J.C.; Hanley, H.J.M.

    1995-01-01

    A study of the Weissenberg effect (rod climbing in a stirred system) based on nonequilibrium molecular dynamics (NEMD) is reported. Simulation results from a soft-sphere fluid are used to obtain a self-consistent free-surface profile of the fluid of finite compressibility undergoing Couette flow between concentric cylinders. A numerical procedure is then applied to calculate the height profile for a hypothetical fluid with thermophysical properties of the soft-sphere liquid and of a dense colloidal suspension. The height profile calculated is identified with shear thickening and the forms of the viscometric functions. The maximum climb occurs between the cylinders rather than at the inner cylinder

  9. Cylinder components properties, applications, materials

    CERN Document Server

    2016-01-01

    Owing to the ever-increasing requirements to be met by gasoline and diesel engines in terms of CO2 reduction, emission behavior, weight, and service life, a comprehensive understanding of combustion engine components is essential today. It is no longer possible for professionals in automotive engineering to manage without the corresponding expertise, whether they work in the field of design, development, testing, or maintenance. This technical book provides in-depth answers to questions about design, production, and machining of cylinder components. In this second edition, every section has been revised and expanded to include the latest developments in the combustion engine. Content Piston rings Piston pins and piston pin circlips Bearings Connecting rods Crankcase and cylinder liners Target audience Engineers in the field of engine development and maintenanceLecturers and students in the areas of mechanical engineering, engine technology, and vehicle constructionAnyone interested in technology Publisher MAH...

  10. Vortex shedding from tandem cylinders

    Science.gov (United States)

    Alam, Md. Mahbub; Elhimer, Mehdi; Wang, Longjun; Jacono, David Lo; Wong, C. W.

    2018-03-01

    An experimental investigation is conducted on the flow around tandem cylinders for ranges of diameter ratio d/ D = 0.25-1.0, spacing ratio L/ d = 5.5-20, and Reynolds number Re = 0.8 × 104-2.42 × 104, where d and D are the diameters of the upstream and downstream cylinders, respectively, L is the distance from the upstream cylinder center to the forward stagnation point of the downstream one. The focus is given on examining the effects of d/ D, L/ d and Re on Strouhal number St, flow structures and fluid forces measured using hotwire, particle image velocimetry (PIV) and load cell measurement techniques, respectively. Changes in d/ D and L/ d in the ranges examined lead to five flow regimes, namely lock-in, intermittent lock-in, no lock-in, subharmonic lock-in and shear-layer reattachment regimes. Time-mean drag coefficient ( C D) and fluctuating drag and lift coefficients ({C^'D} and {C^'L}) are more sensitive to L/ d than d/ D. The scenario is opposite for St where d/ D is more prominent than L/ d to change the St. The detailed facet of the dependence on d/ D and L/ d of C D, {C^'D}, {C^'L} and St is discussed based on shear-layer velocity, approaching velocity, vortex formation length, and wake width.

  11. Prediction of External Corrosion for Steel Cylinders--2002 Report

    International Nuclear Information System (INIS)

    Schmoyer, RLS

    2002-01-01

    . In general, these criteria are based on an area of wall thinning. However, the minimum thickness predicted in this report is essentially for a point--an area of about 0.01 square inches--because the thickness measurements on which the predictions are based are essentially for points. For thicknesses criteria greater than zero, conclusions based on minimum point thicknesses are conservative. Because of the interaction of UF 6 , with atmospheric moisture and steel, a point breach would deteriorate in a year to one-inch diameter hole (DNFSB 1995), however, and so small area approximations should be close for the breach criteria. The most recently collected data, entered into the corrosion model database and not available for the previous report (Schmoyer and Lyon 2001), consists of evaluations of wall loss of 48 inch thin-wall cylinders: 301 cylinders at Paducah, 101 at ETTP, and 139 at Portsmouth; 14 thick-wall cylinders at Portsmouth; and 99 model 30A cylinders at Paducah. However, because of missing values, repeated measures on the same cylinders, outliers, and other data problems, however, not all of these measurements are necessarily used in the corrosion analysis. In several cases, difficulty with the data is also due to a mathematical approach to cylinder corrosion modeling that is used in this report, in Schmoyer and Lyon (2001), and in earlier reports by Lyon. Therefore, an alternative approach is also considered in this report. In previous reports, minimum wall thicknesses have been modeled indirectly through separate models of initial thickness and maximum pit depth. In order to estimate minimum wall thicknesses, the initial thickness and maximum pit depth models are combined using mathematics that assumes independence of the statistical distributions of the initial thicknesses and maximum pit depths. Initial thicknesses are modeled from wall thickness maxima measured at relatively uncorroded wall areas of each cylinder. Maximum pit depths for each cylinder

  12. Recent Results from Analysis of Flow Structures and Energy Modes Induced by Viscous Wave around a Surface-Piercing Cylinder

    Directory of Open Access Journals (Sweden)

    Giancarlo Alfonsi

    2017-01-01

    Full Text Available Due to its relevance in ocean engineering, the subject of the flow field generated by water waves around a vertical circular cylinder piercing the free surface has recently started to be considered by several research groups. In particular, we studied this problem starting from the velocity-potential framework, then the implementation of the numerical solution of the Euler equations in their velocity-pressure formulation, and finally the performance of the integration of the Navier-Stokes equations in primitive variables. We also developed and applied methods of extraction of the flow coherent structures and most energetic modes. In this work, we present some new results of our research directed, in particular, toward the clarification of the main nonintuitive character of the phenomenon of interaction between a wave and a surface-piercing cylinder, namely, the fact that the wave exerts its maximum force and exhibits its maximum run-up on the cylindrical obstacle at different instants. The understanding of this phenomenon becomes of crucial importance in the perspective of governing the entity of the wave run-up on the obstacle by means of wave-flow-control techniques.

  13. Influence of the stacking sequence of layers on the mechanical behavior of polymeric composite cylinders

    International Nuclear Information System (INIS)

    Carvalho, Osni de

    2006-01-01

    This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction. (author)

  14. SU-G-206-06: Analytic Dose Function for CT Scans in Infinite Cylinders as a Function of Scan Length and Cylinder Radius

    Energy Technology Data Exchange (ETDEWEB)

    Bakalyar, D [Henry Ford Health System, Detroit, MI (United States); Feng, W [New York Presbyterian Hospital, Tenafly, NJ (United States); McKenney, S [Children’s National Medical Center, Washington, DC (United States)

    2016-06-15

    Purpose: The radiation dose absorbed at a particular radius ρ within the central plane of a long cylinder following a CT scan is a function of the length of the scan L and the cylinder radius R along with kVp and cylinder composition. An analytic function was created that that not only expresses these dependencies but is integrable in closed form over the area of the central plane. This feature facilitates explicit calculation of the planar average dose. The “approach to equilibrium” h(L) discussed in the TG111 report is seamlessly included in this function. Methods: For a cylindrically symmetric radiation field, Monte Carlo calculations were performed to compute the dose distribution to long polyethylene cylinders for scans of varying L for cylinders ranging in radius from 5 to 20 cm. The function was developed from the resultant Monte Carlo data. In addition, the function was successfully fit to data taken from measurements on the 30 cm diameter ICRU/TG200 phantom using a real-time dosimeter. Results: Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. There are competing effects as the beam penetrates the cylinder from the outside: attenuation, resulting in a decrease; scatter, abruptly increasing at the circumference. This competition may result in an absolute maximum between the center and outer edge leading to a “gull wing” shape for the radial dependence. For the smallest cylinders, scatter may dominate to the extent that there is an absolute maximum at the center. Conclusion: An integrable, analytic function has been developed that provides the radial dependency of dose for the central plane of a scan of length L for cylinders of varying diameter. Equivalently, we have developed h(L,R,ρ).

  15. Integrated approach for stress analysis of high performance diesel engine cylinder head

    Science.gov (United States)

    Chainov, N. D.; Myagkov, L. L.; Malastowski, N. S.; Blinov, A. S.

    2018-03-01

    Growing thermal and mechanical loads due to development of engines with high level of a mean effective pressure determine requirements to cylinder head durability. In this paper, computational schemes for thermal and mechanical stress analysis of a high performance diesel engine cylinder head were described. The most important aspects in this approach are the account of temperature fields of conjugated details (valves and saddles), heat transfer modeling in a cooling jacket of a cylinder head and topology optimization of the detail force scheme. Simulation results are shown and analyzed.

  16. Flow around a cylinder surrounded by a permeable cylinder in shallow water

    Energy Technology Data Exchange (ETDEWEB)

    Ozkan, Gokturk M.; Akilli, Huseyin; Sahin, Besir [Cukurova University, Department of Mechanical Engineering, Faculty of Engineering and Architecture, Adana (Turkey); Oruc, Vedat [Dicle University, Department of Mechanical Engineering, Diyarbakir (Turkey)

    2012-12-15

    The change in flow characteristics downstream of a circular cylinder (inner cylinder) surrounded by an outer permeable cylinder was investigated in shallow water using particle image velocimetry technique. The diameter of the inner cylinder and the water height were kept constant during the experiments as d=50 mm and h{sub w}=25 mm, respectively. The depth-averaged free-stream velocity was also kept constant as U=170 mm/s which corresponded to a Reynolds number of Re{sub d}=8,500 based on the inner cylinder diameter. In order to examine the effect of diameter and porosity of the outer cylinder on flow characteristics of the inner cylinder, five different outer cylinder diameters (D=60, 70, 80, 90 and 100 mm) and four different porosities ({beta}=0.4, 0.5, 0.6 and 0.7) were used. It was shown that both porosity and outer cylinder diameter had a substantial effect on the flow characteristics downstream of the circular cylinder. Turbulent statistics clearly demonstrated that in comparison with the bare cylinder (natural case), turbulent kinetic energy and Reynolds stresses decreased remarkably when an outer cylinder was placed around the inner cylinder. Thereby, the interaction of shear layers of the inner cylinder has been successfully prevented by the presence of outer cylinder. It was suggested by referring to the results that the outer cylinder having 1.6{<=}D/d{<=}2.0 and 0.4{<=}D/d{<=}0.6 should be preferred to have a better flow control in the near wake since the peak magnitude of turbulent kinetic energy was considerably low in comparison with the natural case and it was nearly constant for these mentioned porosities {beta}, and outer cylinder to inner cylinder diameter ratios D/d. (orig.)

  17. Material properties of Ni-Cr-Al alloy and design of a 4 GPa class non-magnetic high-pressure cell

    CERN Document Server

    Uwatoko, Y; Ueda, K; Uchida, A; Kosaka, M; Mori, N; Matsumoto, T

    2002-01-01

    The Ni-Cr-Al Russian alloy was prepared. Its magnetic and mechanical properties were better than those of MP35N alloy. We fabricated the a piston-cylinder-type hybrid high-pressure cell using the Ni-Cr-Al alloy. It has been found that the maximum working pressure can be repeatedly raised to 3.5 GPa at T = 2 K without any difficulties.

  18. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  19. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  20. Transient natural convection with density inversion from a horizontal cylinder

    Science.gov (United States)

    Wang, P.; Kahawita, R.; Nguyen, D. L.

    1992-01-01

    This paper is devoted to a numerical investigation of the free convection flow about a horizontal cylinder maintained at 0 °C in a water ambient close to the point of maximum density. Complete numerical solutions covering both the transient as well as steady state have been obtained. Principal results indicate that the proximity of the ambient temperature to the point of maximum density plays an important role in the type of convection pattern that may be obtained. When the ambient temperature is within 4.7 °Ccylinder with both upward and downward flow occurring in proximity to the cylinder in two distinct recirculating zones, generally separated by the 4 °C isotherm when Tamb<5.7 °C. The dual flow behavior is significantly modified as the ambient temperature is altered, disappearing when the ambient temperature is above 8 °C, or below 4.7 °C. Furthermore, when the ambient temperature is within about 4.8 °C

  1. Synthesis of microparticles with complex compositions in a xenon high-pressure chamber (550 bar) under irradiation by braking radiation with a maximum energy of 10 MeV

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Gul'bekyan, G.G.; Myshinskiy, G.V.; Sabel'nikov, A.V.

    2016-01-01

    Natural xenon at a pressure of 550 bar in a high pressure chamber (XeHPC) was irradiated during 2,59 · 10 5 s by bremsstrahlung with a maximum energy of 10 MeV at the electron accelerator MT-25 microtron with an electron beam intensity of 20–22μA. The final electron fluence was 4.74 · 10 19 electrons. The growth of pressure versus temperature during the stationary exposure mode grew at first up to 620 bar and then dropped to 550 bar. After opening of the XeHPC both of the internal chambers with all the structures, but without gas, were measured using a γ-germanium detector (Canberra) during 15 h each for measurement of the background and short-lived isotopes. During a visual inspection of the interior surfaces of the XeHPC inner assembly, a visible coating of substantial thickness and greenish-yellowish color was observed. The research carried out by scanning electron microscopy (SEM) and X-ray micro-probe analysis (XMPA) allowed us to determine the elemental composition of synthesized particles. [ru

  2. Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa

    Science.gov (United States)

    Sakurai, T.; Fujimoto, K.; Matsui, R.; Kawasaki, K.; Okubo, S.; Ohta, H.; Matsubayashi, K.; Uwatoko, Y.; Tanaka, H.

    2015-10-01

    A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2-based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10 T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S = 1 system with the single ion anisotropy NiSnCl6 · 6H2O and the S = 1 / 2 quantum spin system CsCuCl3. We performed ESR measurements of these systems above 2 GPa successfully.

  3. Pneumatic pressure wave generator provides economical, simple testing of pressure transducers

    Science.gov (United States)

    Gaal, A. E.; Weldon, T. P.

    1967-01-01

    Testing device utilizes the change in pressure about a bias or reference pressure level produced by displacement of a center-driven piston in a closed cylinder. Closely controlled pneumatic pressure waves allow testing under dynamic conditions.

  4. A COMPUTATIONAL STUDY OF THE ACTUATION SPEED OF THE HYDRAULIC CYLINDER UNDER DIFFERENT PORTS’ SIZES AND CONFIGURATIONS

    Directory of Open Access Journals (Sweden)

    M. O. ABDALLA

    2015-02-01

    Full Text Available The discharged oil from hydraulic cylinder, during its operation, is highly restricted by the small sized outlets. As a result, a back pressure builds up and the piston motion, therefore, is slowed down; the system pump has to do additional work to overcome this hydraulic resistance so as to preserve the required speed. In this study the possibility of improvement of the actuation speed of the hydraulic cylinders was investigated and analysed. Both a four-port cylinder and a resized-ports cylinder were proposed as fast cylinders. FLUENT 6.3 was used for the simulation of the oil flow field of the hydraulic cylinders. Results showed that relation between discharge flow and the outlets diameters is best described by a power law having coefficients partially depending on the system pressure. It had also shown that for any given total outlet area, the actuation speed of the single outlet cylinders is always higher than that of the double outlets cylinders. In one case where the total outlet area is 3.93E-05m2, the actuation speed of the single outlet cylinder is 21% higher than that of the double outlets cylinder; whereas, when doubling the total outlet area the different is reduced to just 6% . Resizing the outlet for small ports was more efficient than using multi-outlets; while for a large ports it shows no significant difference to use either one outlet port or multi-outlets. Both the solutions of resizing or ports addition need special valve to be fit to the cylinder so that the cylinder could be effectively operated under the control of the proportional valve.

  5. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  6. Transient thermal stresses in circular cylinder under intermittently sudden heat generation

    International Nuclear Information System (INIS)

    Sugano, Y.; Saito, K.; Takeuti, Y.

    1975-01-01

    The thermal stresses associated with the transient temperature distribution arising in a circular cylinder under intermittently changing sudden heat generation over a finite band and with heat loss to a surrounding medium on the remainder of the cylinder surface are exactly analysed. For the first time the temperature field in a circular cylinder under sudden heat generation over a finite band of the cylinder surface is determined by combined use of Fourier cosine, Laplace transforms in axial position and time, respectively. Secondly it is assumed that the temperature fields in a circular cylinder subjected to heat generation Qsub(i) (i=0, 1, 2, ...) independently over a finite band are given by T 0 (r,z,t), T 1 (r,z,t), T 2 (r,z,t),... respectively. Tsub(i)(r,z,t) indicates the temperature field before the i-th heat generation Qsub(i). The thermal stresses associated with the temperature field described above are analysed by using the Hoyle stress functions. Numerical calculations are carried out for the extensive case of the ratio of the heat-generating length to the diameter of cylinder. It is found that the time in which the maximum stresses occur on the cylinder surface does not depend on the heat-generating length-to-diameter ratio

  7. Criticality Safety Evaluation for 30B and 48X UF6 Cylinders for Transportation and Storage

    International Nuclear Information System (INIS)

    Mokhatri, Homami Zahra; Nematollahi, Mohammadreza; Kamyab, Shahabeddin

    2011-01-01

    30B and 48X cylinders are two standard containers have been used for transportation and storage of uranium hexafluoride with 21/2-ton and 10-ton loading capacity, respectively. For the sake of nuclear safety, the long-term safe storage and transportation of the cylinders are necessary to be concerned. Safe limits in handling and storage of 30B and 48X cylinders from the criticality safety considerations, has been investigated in this paper, by using the MCNP.4C code with ENDF/B-VI library data for the neutron cross sections. An infinite array model (with and without over pack) incorporating an internal H/U ratio of 0.088 was then developed to determine the optimal interstitial moderation. The maximum k eff value for the conditions of optimal interstitial moderation with the premise of no water leakage into the UF 6 cylinder has been shown to be 0.79209 ± 0.0011 for the 30B cylinder and 0.7625±0.0013 for 48X cylinder with 5 wt % 235 U enrichment. Based on this evaluation, the 30B and 48X UF 6 cylinders with 5 wt % 235 U enrichment meet the 10 CFR part 71 criteria for Fissile Class I packages, even in the worst case, and has a Transport Index (TI) of zero for criticality safety purposes

  8. Mechanical Integrity of Copper Canister Lid and Cylinder

    International Nuclear Information System (INIS)

    Karlsson, Marianne

    2002-01-01

    This report compiles finite element analyses performed to ensure the structural integrity of canisters used for storing of nuclear fuel waste of type BWR. The report comprises analyses performed on the canister lid and cylinder casing in order to determine static and long-term strength of the structure. The report analyses the mechanical response of the lid and flange of the copper canister when subjected to loads caused by pressure from swelling bentonite and from ground water at a depth of 500 meter. The loads acting on the canister are somewhat uncertain and the cases investigated in this report are possible cases. Load cases analysed are: Pressure 15 MPa uniformly distributed on lid and 5 MPa uniformly distributed on cylinder; Pressure 5 MPa uniformly distributed on lid and 15 MPa uniformly distributed on cylinder; Pressure 20 MPa uniformly distributed on lid and cylinder; Side pressures 10 MPa and 20 MPa uniformly distributed on part of the cylinder. Creep analyses are also performed in order to estimate the stresses that will arise when the canister is placed in the repository. The analyses in this report are recreated from the original analyses but the models differ in geometry. Also, there is no information in the original reports on material data, time-independent as well as creep data, and analysis procedure. The data used in the recreated analyses are based on information from References 2, 3, 6 and 7. The results presented in this report are based on the supplementary analyses. These results differ from the original results. Most likely this is due to differences in model geometry. The original results are appended to the report and are summarised for comparison with results from the supplementary analyses. Otherwise, these results are not further discussed. For all load cases, high tensile stresses are found in the lid fillet between the planar part and the flange. High tensile stresses are also found in the weld surface and on the outer side of the

  9. Inner cylinder of the CMS vacuum tank.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the outer cylinder already attached to the innermost ring of the barrel yoke.

  10. Overseas shipments of 48Y cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, R.T.; Furlan, A.S. [Cameco Corp., Port Hope, Ontario (Canada)

    1991-12-31

    This paper describes experiences with two incidents of overseas shipments of uranium hexafluoride (UF{sub 6}) cylinders. The first incident involved nine empty UF{sub 6} cylinders in enclosed sea containers. Three UF{sub 6} cylinders broke free from their tie-downs and damaged and contaminated several sea containers. This paper describes briefly how decontamination was carried out. The second incident involved a shipment of 14 full UF{sub 6} cylinders. Although the incident did not cause an accident, the potential hazard was significant. The investigation of the cause of the near accident is recounted. Recommendations to alleviate future similar incidents for both cases are presented.

  11. Optimization and improvement of Halbach cylinder design

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2008-01-01

    possible volume of magnets with a given mean flux density in the cylinder bore. The volume of the cylinder bore could also be significantly increased by only slightly increasing the volume of the magnets, for a fixed mean flux density. Placing additional blocks of magnets on the end faces of the Halbach...... that this parameter was optimal for long Halbach cylinders with small rex. Using the previously mentioned additional blocks of magnets can improve the parameter by as much as 15% as well as improve the homogeneity of the field in the cylinder bore. ©2008 American Institute of Physics...

  12. Swap your propane cylinder with SWOP

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    A very successful propane cylinder exchange program operated by South Western Ontario Propane (SWOP) Inc., was described. The company specializes in propane cylinder exchange and in the refurbishing and marketing of top quality domestic and commercial propane cylinders. The company, currently operating out of Bradford, Ontario, was started in 1991. It employs a staff of 25 in peak season. It has some 200 exchange outlets throughout Ontario and has accepted outdated tanks from as far west as Manitoba and as far east as Quebec. A typical transaction involves bringing an empty cylinder to the nearest SWOP location and exchanging it for a full SWOP cylinder. SWOP does about 50,000 to 60,000 exchanges a year. For the consumer, the program is said to be cheaper, safer and more convenient than getting refills. As far as dealers are concerned operating a SWOP exchange outlet can add extra profits, attract new customers, and build additional consumer loyalty without the need for extra staff or additional indoor space. SWOP delivers full cylinders to exchange outlets on a weekly basis when it also picks up the empty cylinders. At dealer locations, the cylinders (full or empty) are stored in company -designed vandal-proof metal cages. Major expansion of the network of outlets and the cylinder refurbishing and refilling facilities are planned for 1998

  13. Wake flow behaviour behind a smaller cylinder oscillating in the wake of an upstream stationary cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yangyang; Sun, Zhilin [Ocean College, Zhejiang University, Hangzhou 310058 (China); Tan, Danielle S [Maritime Research Centre, Nanyang Technological University, Singapore 639798 (Singapore); Yu, Dingyong [College of Engineering, Ocean University of China, 266100 (China); Tan, Soon Keat, E-mail: yygao@zju.edu.cn [Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 639798 (Singapore)

    2014-04-01

    The flow patterns around a cylinder oscillating freely in the wake of a larger cylinder upstream were investigated using the particle image velocimetry technique. The upstream cylinder was fixed at both ends while the downstream smaller cylinder was held by springs such that it was free to oscillate in the transverse direction. The flow patterns, amplitudes of oscillation and vortex shedding frequencies were compared with those of a single cylinder. In the presence of the upstream cylinder, the three parameters characterizing the oscillation response of the smaller cylinder—amplitude of oscillation, vortex shedding frequency and Reynolds stresses—were greatly reduced. While their magnitude increased with gap ratio, these three parameters were still smaller than the corresponding magnitudes for a single oscillating cylinder. The peak values of turbulence statistics such as Reynolds shear stress and normal stress behind the oscillating downstream cylinder were similarly reduced, and increased with gap ratios. (paper)

  14. Natural Gas Vehicle Cylinder Safety, Training and Inspection Project

    Energy Technology Data Exchange (ETDEWEB)

    Hank Seiff

    2008-12-31

    Under the auspices of the National Energy Technology Laboratory and the US Department of Energy, the Clean Vehicle Education Foundation conducted a three-year program to increase the understanding of the safe and proper use and maintenance of vehicular compressed natural gas (CNG) fuel systems. High-pressure fuel systems require periodic inspection and maintenance to insure safe and proper operation. The project addressed the needs of CNG fuel containers (cylinders) and associated high-pressure fuel system components related to existing law, codes and standards (C&S), available training and inspection programs, and assured coordination among vehicle users, public safety officials, fueling station operators and training providers. The program included a public and industry awareness campaign, establishment and administration of a cylinder inspector certification training scholarship program, evaluation of current safety training and testing practices, monitoring and investigation of CNG vehicle incidents, evaluation of a cylinder recertification program and the migration of CNG vehicle safety knowledge to the nascent hydrogen vehicle community.

  15. View factor for radiation heat exchange between the wall and end of a cylinder

    International Nuclear Information System (INIS)

    Al-Bahadili, H.; Wood, J.

    1991-01-01

    In a paper by previous authors (Carlson and Garcia (1984) Ann. Nucl. Energy Vol 11, No 4), a numerical integration technique (trapezoidal rule) is developed for the approximate calculation of view factors for radiant heat transfer, for both internal and external radiation, from the curved surface of a right circular cylinder. In that paper the variation of view factor for internal radiation (wall to bottom of cylinder) with height, H, of the cylinder, is shown to reach a maximum value of about 0.36 when H is about 0.3. This behaviour is remarked upon in the text. We wish to make two points: (i) the internal view factors for the cylinder can be determined analytically (ii) the view factor behavior shown is erroneous. In fact, the view factor decreases monatonically as H increases, achieving its greatest value (0.5) as H tends to zero. H is normalised to a radius of unity. (author)

  16. Development of Advanced In-Cylinder Components and Tribological Systems for Low Heat Rejection Diesel Engines

    Science.gov (United States)

    Yonushonis, T. M.; Wiczynski, P. D.; Myers, M. R.; Anderson, D. D.; McDonald, A. C.; Weber, H. G.; Richardson, D. E.; Stafford, R. J.; Naylor, M. G.

    1999-01-01

    In-cylinder components and tribological system concepts were designed, fabricated and tested at conditions anticipated for a 55% thermal efficiency heavy duty diesel engine for the year 2000 and beyond. A Cummins L10 single cylinder research engine was used to evaluate a spherical joint piston and connecting rod with 19.3 MPa (2800 psi) peak cylinder pressure capability, a thermal fatigue resistant insulated cylinder head, radial combustion seal cylinder liners, a highly compliant steel top compression ring, a variable geometry turbocharger, and a microwave heated particulate trap. Components successfully demonstrated in the final test included spherical joint connecting rod with a fiber reinforced piston, high conformability steel top rings with wear resistant coatings, ceramic exhaust ports with strategic oil cooling and radial combustion seal cylinder liner with cooling jacket transfer fins. A Cummins 6B diesel was used to develop the analytical methods, materials, manufacturing technology and engine components for lighter weight diesel engines without sacrificing performance or durability. A 6B diesel engine was built and tested to calibrate analytical models for the aluminum cylinder head and aluminum block.

  17. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    Directory of Open Access Journals (Sweden)

    Ma Xiaobing

    2015-01-01

    Full Text Available An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life test due to the time limitation. Therefore, most of the data presented to be high censored in high stress level and zero-failure data in low stress level. When using the traditional method for rupture life prediction, the results showed to be of lower confidence. In this study, the consistency of failure mechanism for carbon fiber and cylinder was analyzed firstly. According to the analysis result, the statistical test information of carbon fiber could be utilized for the accelerated model constitution. Then, rupture life prediction method for cylinder was proposed based on the accelerated life test data and carbon fiber test data. In this way, the life prediction accuracy of cylinder could be improved obviously, and the results showed that the accuracy of this method increased by 35%.

  18. A comparative analysis on the shed vortices from the wake of finned, foam-wrapped cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Khashehchi, Morteza [Department of Agro-Technology, College of Aburaihan, University of Tehran, Tehran (Iran, Islamic Republic of); Ashtiani Abdi, Iman; Hooman, Kamel, E-mail: m.khashehchi@ut.ac.ir [School of Mechanical and mining Engineering, University of Queensland, Brisbane (Australia)

    2017-08-15

    The wake characteristics behind a finned and a foam-wrapped circular cylinder has been compared in a study (Khashehchi et al 2014 Exp. Therm. Fluid Sci. 52 328–38) done by the Authors. In this paper, the shed vortices from the wake of the same cylinders have been studied. Shedding in a bluff body has an important effect on increasing the pressure drop downstream of the object. Here, we have used particle image velocimetry to investigate the detached vortices from the wake behind a foam-wrapped and a finned cylinder. The standard case of cross-flow over a bare cylinder, i.e. no surface extension, has also been tested as a benchmark. The experiments have been performed for Reynolds numbers 2000 based on the mean air velocity and the cylinder’s outer diameter. To identify the features of each aforementioned case, linear stochastic estimation has been applied to the velocity fields. Results show that unlike the fin, adding foam to the cylinder surface increases the size of detached vortices and amplifies the core strength. Moreover, foam-wrapped cylinder in contrast to the finned one produces strong three-dimensionality. Interestingly, finned cylinder’s results show less three-dimensionality compared to the bare cylinder. (paper)

  19. Fabrication of 4-cylinder transparent engine and measurement of the flame propagation behavior with high speed camera at idle condition

    Energy Technology Data Exchange (ETDEWEB)

    Joo, S.H. [Yonsei University Graduate School, Seoul (Korea, Republic of); Chun, K.M. [Yonse University, Seoul (Korea, Republic of)

    1998-04-01

    A transparent engine for visualization study is made using a production 4 cylinder engine. Flame propagation results from individual combustion cycles with high-speed cinematography are presented and discussed for idle condition. The flame propagation image and the in-cylinder pressure were obtained simultaneously, and the image processing software which can calculate the flame area and the flame center was developed. The flame propagation behavior of each cycle shows high cyclic variations, and there are linear correlation between flame area and the in-cylinder pressure. (author). 4 refs., 6 figs., 1 tab.

  20. Large eddy simulation of the subcritical flow over a V grooved circular cylinder

    International Nuclear Information System (INIS)

    Alonzo-García, A.; Gutiérrez-Torres, C. del C.; Jiménez-Bernal, J.A.

    2015-01-01

    Highlights: • We compared numerically the turbulent flow over a smooth circular cylinder and a V grooved cylinder in the subcritical regime. • Turbulence intensities in both streamwise and normal direction suffered attenuations. • The swirls structures on grooves peaks seemed to have a cyclic behavior. • The evolution of the flow inside grooves showed that swirls structures located in peaks suffered elongations in the normal direction. • The secondary vortex structures formed in the grooved cylinder near wake were smaller in comparison of the smooth cylinder flow. - Abstract: In this paper, a comparative numerical study of the subcritical flow over a smooth cylinder and a cylinder with V grooves (Re = 140,000) is presented. The implemented technique was the Large Eddy Simulation (LES), which according to Kolmogorov's theory, resolves directly the most energetic largest eddies and models the smallest and considered universal high frequency ones. The Navier-Stokes (N-S) equations were solved using the commercial software ANSYS FLUENT V.12.1, which applied the finite volume method (FVM) to discretize these equations in their unsteady and incompressible forms. The grid densities were 2.6 million cells and 13.5 million cells for the smooth and V grooved cylinder, respectively. Both meshes were composed of structured hexahedral cells and close to the wall of the cylinders, additional refinements were employed in order to obtain y +<5 values. All cases were simulated during at least 15 vortex shedding cycles with the aim of obtaining significant statistical data. Results: showed that for both cases (smooth and V grooved cylinder flow), the numerical code was capable of reproducing the most important physical quantities of the subcritical regime. Velocity distribution and turbulence intensity in the flow direction suffered a slight attenuation along the wake, as a consequence of grooves perturbation, which also caused an increase in the pressure coefficient

  1. Composite high-pressure vessels for hydrogen storage in mobile application. Pt. 1 / Light weight composite cylinders for compressed hydrogen. Pt. 2 - custom made hydrogen storage tanks and vessels

    Energy Technology Data Exchange (ETDEWEB)

    Rasche, C. [MCS Cylinder Systems GmbH, Dinslaken (Germany)

    2000-07-01

    Recent developments on fuel cell technology demonstrated the feasibility of propelling vehicles by converting fuel directly into electricity. Fuel cells conveniently use either compressed (CGH{sub 2}) or liquid hydrogen (LH{sub 2}) or methanol as the fuel source from a tank. Mobile storage of these fuelling will become an urgent need as this technology will come into series production expected for 2010. Due to the requirements on mobile hydrogen storage and the energy losses in the hydrogen-to-application-chain, a light-weight and energetic qualities and minimise ist bulky nature. Mobile storage of hydrogen can be realised either at high pressure values (> 20 MPa) or at deep temperatures (<-253 C). CGH{sub 2}: In the last few years, the introduction of natural gas driven vehicles has seen the development of compact mobile pressurised gas tanks in principle, this storage technique is also applicable for the compressed storage of hydrogen at filling pressures of > 20 MPa. LH{sub 2} : Storing hydrogen or natural gases in general in the liquid phase is accomplished either by applying a overpressure or keeping it below the phase transition temperature at ambient pressure in super insulated devices. (orig.)

  2. A Convenient Storage Rack for Graduated Cylinders

    Science.gov (United States)

    Love, Brian

    2004-01-01

    An attempt is made to find a solution to the occasional problem of a need for storing large numbers of graduated cylinders in many teaching and research laboratories. A design, which involves the creation of a series of parallel channels that are used to suspend inverted graduated cylinders by their bases, is proposed.

  3. Thermal convection of liquid sodium in inclined cylinders

    Science.gov (United States)

    Khalilov, Ruslan; Kolesnichenko, Ilya; Pavlinov, Alexander; Mamykin, Andrey; Shestakov, Alexander; Frick, Peter

    2018-04-01

    The effect of inclination on the low Prandtl number turbulent convection in a cylinder of unit aspect ratio was studied experimentally. The working fluid was sodium (Prandtl number Pr =0.0094 ), the measurements were performed for a fixed Rayleigh number Ra =(1.47 ±0.03 ) ×107 , and the inclination angle varied from β =0∘ (the Rayleigh-Bénard convection, the temperature gradient is vertical) up to β =90∘ (the applied temperature gradient is horizontal) with a step Δ β =10∘ . The effective axial heat flux characterized by the Nusselt number is minimal at β =0∘ and demonstrates a smooth growth with the increase of the cylinder inclination, reaching a maximum at angle β ≈70∘ and decreasing with a further increase of β . The maximal value of the normalized Nusselt number Nu (β )/Nu (0 ) was 1.21. In general, the dependence of Nu (β ) in a cylinder with unit aspect ratio is similar to what was observed in sodium convection in inclined long cylinders but is much weaker. The structure of the flow undergoes a significant transformation with inclination. Under moderate inclination (β ≲30∘ ), the fluctuations are strong and are provided by regular oscillations of large-scale circulation (LSC) and by turbulence. Under large inclination (β >60∘ ), the LSC is regular and the turbulence is weak, while in transient regimes (30∘border of transient and large inclinations. We find the first evidence of strong LSC fluctuations in low Prandtl number convective flow under moderate inclination. The rms azimuthal fluctuations of LSC, about 27∘ at β =0∘ , decrease almost linearly up to β =30∘ , where they are about 9∘. The angular fluctuations in the vicinity of the end faces are much stronger (about 37∘ at β =0∘ ) and weakly decrease up to β =20∘ . The strong anticorrelation of the fluctuations in two halves of the cylinder indicates the torsional character of LSC fluctuations. At β =30∘ , the intensity of the oscillations at the

  4. Numerical simulation and global linear stability analysis of low-Re flow past a heated circular cylinder

    KAUST Repository

    Zhang, Wei

    2016-03-31

    We perform two-dimensional unsteady Navier-Stokes simulation and global linear stability analysis of flow past a heated circular cylinder to investigate the effect of aided buoyancy on the stabilization of the flow. The Reynolds number of the incoming flow is fixed at 100, and the Richardson number characterizing the buoyancy is varied from 0.00 (buoyancy-free case) to 0.10 at which the flow is still unsteady. We investigate the effect of aided buoyancy in stabilizing the wake flow, identify the temporal and spatial characteristics of the growth of the perturbation, and quantify the contributions from various terms comprising the perturbed kinetic energy budget. Numerical results reveal that the increasing Ri decreases the fluctuation magnitude of the characteristic quantities monotonically, and the momentum deficit in the wake flow decays rapidly so that the flow velocity recovers to that of the free-stream; the strain on the wake flow is reduced in the region where the perturbation is the most greatly amplified. Global stability analysis shows that the temporal growth rate of the perturbation decreases monotonically with Ri, reflecting the stabilization of the flow due to aided buoyancy. The perturbation grows most significantly in the free shear layer separated from the cylinder. As Ri increases, the location of maximum perturbation growth moves closer to the cylinder and the perturbation decays more rapidly in the far wake. The introduction of the aided buoyancy alters the base flow, and destabilizes the near wake shear layer mainly through the strain-induced transfer term and the pressure term of the perturbed kinetic energy, whereas the flow is stabilized in the far wake as the strain is alleviated. © 2016 Elsevier Ltd. All rights reserved.

  5. Numerical simulation and global linear stability analysis of low-Re flow past a heated circular cylinder

    KAUST Repository

    Zhang, Wei; Samtaney, Ravi

    2016-01-01

    We perform two-dimensional unsteady Navier-Stokes simulation and global linear stability analysis of flow past a heated circular cylinder to investigate the effect of aided buoyancy on the stabilization of the flow. The Reynolds number of the incoming flow is fixed at 100, and the Richardson number characterizing the buoyancy is varied from 0.00 (buoyancy-free case) to 0.10 at which the flow is still unsteady. We investigate the effect of aided buoyancy in stabilizing the wake flow, identify the temporal and spatial characteristics of the growth of the perturbation, and quantify the contributions from various terms comprising the perturbed kinetic energy budget. Numerical results reveal that the increasing Ri decreases the fluctuation magnitude of the characteristic quantities monotonically, and the momentum deficit in the wake flow decays rapidly so that the flow velocity recovers to that of the free-stream; the strain on the wake flow is reduced in the region where the perturbation is the most greatly amplified. Global stability analysis shows that the temporal growth rate of the perturbation decreases monotonically with Ri, reflecting the stabilization of the flow due to aided buoyancy. The perturbation grows most significantly in the free shear layer separated from the cylinder. As Ri increases, the location of maximum perturbation growth moves closer to the cylinder and the perturbation decays more rapidly in the far wake. The introduction of the aided buoyancy alters the base flow, and destabilizes the near wake shear layer mainly through the strain-induced transfer term and the pressure term of the perturbed kinetic energy, whereas the flow is stabilized in the far wake as the strain is alleviated. © 2016 Elsevier Ltd. All rights reserved.

  6. Magnetothermoelastic creep analysis of functionally graded cylinders

    International Nuclear Information System (INIS)

    Loghman, A.; Ghorbanpour Arani, A.; Amir, S.; Vajedi, A.

    2010-01-01

    This paper describes time-dependent creep stress redistribution analysis of a thick-walled FGM cylinder placed in uniform magnetic and temperature fields and subjected to an internal pressure. The material creep, magnetic and mechanical properties through the radial graded direction are assumed to obey the simple power law variation. Total strains are assumed to be the sum of elastic, thermal and creep strains. Creep strains are time, temperature and stress dependent. Using equations of equilibrium, stress-strain and strain-displacement a differential equation, containing creep strains, for displacement is obtained. Ignoring creep strains in this differential equation a closed form solution for the displacement and initial magnetothermoelastic stresses at zero time is presented. Initial magnetothermoelastic stresses are illustrated for different material properties. Using Prandtl-Reuss relation in conjunction with the above differential equation and the Norton's law for the material uniaxial creep constitutive model, the radial displacement rate is obtained and then the radial and circumferential creep stress rates are calculated. Creep stress rates are plotted against dimensionless radius for different material properties. Using creep stress rates, stress redistributions are calculated iteratively using magnetothermoelastic stresses as initial values for stress redistributions. It has been found that radial stress redistributions are not significant for different material properties, however major redistributions occur for circumferential and effective stresses.

  7. Maximum Evaporation Rates of Water Droplets Approaching Obstacles in the Atmosphere Under Icing Conditions

    Science.gov (United States)

    Lowell, H. H.

    1953-01-01

    When a closed body or a duct envelope moves through the atmosphere, air pressure and temperature rises occur ahead of the body or, under ram conditions, within the duct. If cloud water droplets are encountered, droplet evaporation will result because of the air-temperature rise and the relative velocity between the droplet and stagnating air. It is shown that the solution of the steady-state psychrometric equation provides evaporation rates which are the maximum possible when droplets are entrained in air moving along stagnation lines under such conditions. Calculations are made for a wide variety of water droplet diameters, ambient conditions, and flight Mach numbers. Droplet diameter, body size, and Mach number effects are found to predominate, whereas wide variation in ambient conditions are of relatively small significance in the determination of evaporation rates. The results are essentially exact for the case of movement of droplets having diameters smaller than about 30 microns along relatively long ducts (length at least several feet) or toward large obstacles (wings), since disequilibrium effects are then of little significance. Mass losses in the case of movement within ducts will often be significant fractions (one-fifth to one-half) of original droplet masses, while very small droplets within ducts will often disappear even though the entraining air is not fully stagnated. Wing-approach evaporation losses will usually be of the order of several percent of original droplet masses. Two numerical examples are given of the determination of local evaporation rates and total mass losses in cases involving cloud droplets approaching circular cylinders along stagnation lines. The cylinders chosen were of 3.95-inch (10.0+ cm) diameter and 39.5-inch 100+ cm) diameter. The smaller is representative of icing-rate measurement cylinders, while with the larger will be associated an air-flow field similar to that ahead of an airfoil having a leading-edge radius

  8. Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders

    International Nuclear Information System (INIS)

    Rana, M.A.; Siddiqui, A.M.; Qamar, Rashid

    2009-01-01

    The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties

  9. Experimental investigations of a single cylinder genset engine with common rail fuel injection system

    Directory of Open Access Journals (Sweden)

    Gupta Paras

    2014-01-01

    Full Text Available Performance and emissions characteristics of compression ignition (CI engines are strongly dependent on quality of fuel injection. In an attempt to improve engine combustion, engine performance and reduce the exhaust emissions from a single cylinder constant speed genset engine, a common rail direct injection (CRDI fuel injection system was deployed and its injection timings were optimized. Results showed that 34°CA BTDC start of injection (SOI timings result in lowest brake specific fuel consumption (BSFC and smoke opacity. Advanced injection timings showed higher cylinder peak pressure, pressure rise rate, and heat release rate due to relatively longer ignition delay experienced.

  10. Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Rana, M.A. [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)], E-mail: mafzalrana@yahoo.com; Siddiqui, A.M. [Department of Mathematics, Pennsylvania State University, York Campus, York, PA 17403 (United States); Qamar, Rashid [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)

    2009-01-15

    The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties.

  11. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  12. Structural Integrity Assessment for SSDM Hydraulic Cylinder of JRTR

    International Nuclear Information System (INIS)

    Kim, Sanghaun; Lee, Jin Haeng; Cho, Yeonggarp; Yoo, Yeonsik

    2014-01-01

    In HANARO, there are four Control Rod Drive Mechanisms (CRDMs) with an individual step motor and four Shutoff (SO) Units with an individual hydraulic system located at the top of reactor pool. The absorber rods in SO units are poised at the top of the core by the hydraulic force during normal operation. The rods of SO units drop by gravity as the first reactor showdown mechanism when a trip is commended by the reactor protection system (RPS). The CRDMs act as the first reactor shutdown mechanism and reactor regulating as well. The top-mounted SSDM driven by the hydraulic system for the JRTR is under design in KAERI. The SSDM provides an alternate and independent means of reactor shutdown. The second shutdown rods (SSRs) of the SSDM are poised at the top of the core by the hydraulic system during the normal operation and drop by gravity for the reactor trip. Based on the proven technology of the design, operation and maintenance for HANARO, the SSDM for the JRTR has been optimized by the design improvement from the experience and test. This paper aims for the structural integrity assessment for SSDM hydraulic cylinder which is designed on the basis of the SO unit of HANARO but optimized with the new core environment (i. e., geometrical, physical, etc.) of JRTR. A stress analysis of the hydraulic cylinder for the SSDM used in JRTR has been performed through the conservative approach with the uncertainties in the system design step. The crank's pinch load with no slip between the bearing (stiffener) plate of hydraulic cylinder and base plate of mount bracket during SSE has been calculated by considering the design and seismic load combination. The stress by the load combination satisfies the Class 3 criteria given Table NG-3325 of Section III of the ASME Code. The maximum stresses are at the clamp contact region in the cylinder

  13. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  14. Maximum Water Hammer Sensitivity Analysis

    OpenAIRE

    Jalil Emadi; Abbas Solemani

    2011-01-01

    Pressure waves and Water Hammer occur in a pumping system when valves are closed or opened suddenly or in the case of sudden failure of pumps. Determination of maximum water hammer is considered one of the most important technical and economical items of which engineers and designers of pumping stations and conveyance pipelines should take care. Hammer Software is a recent application used to simulate water hammer. The present study focuses on determining significance of ...

  15. Research on a lubricating grease print process for cylindrical cylinder

    Science.gov (United States)

    Yang, Liu; Zhang, Xuan; Wang, XianYan; Tan, XiaoYan

    2017-09-01

    In vehicle braking system and clutch system of transmission, there is always a kind of cylindrical component dose reciprocating motion. The main working method is the reciprocating motion between the rubber sealing parts and cylindrical parts, the main factor affects the service life of the product is the lubricating performance of the moving parts. So the lubricating performance between cylinders and rubber sealing rings is particularly important, same as the quality of the grease applies on the surface of the surface of cylinder. Traditional method of manually applying grease has some defects such as applying unevenly, applying tools like brush and cloth easily falls off and affect the cleanness of products, contact skin easily cause allergy, waste grease due to the uncontrollable of grease quantity using in applying, low efficiency of manual operation. An automatic, quantitative and high pressure applying equipment is introduced in this document to replace the traditional manually applying method, which can guarantee the applying quality of the grease which are painted on the surface of cylinder and bring economic benefits to the company.

  16. Transient flow analysis of the single cylinder for the control rod hydraulic driving system

    International Nuclear Information System (INIS)

    Sun, Xinming; Qin, Benke; Bo, Hanliang

    2017-01-01

    Highlights: • The control rod hydraulic driving system(CRHDS) is a new type of built-in control rod drive technology. The hydraulic cylinder is the main component of the CRHDS. • Transient flow phenomenon in the CRHDS is studied by experiments under different working conditions. • The working mechanism of the hydraulic cylinder step motion and the key characteristic parameters are analyzed based on the experimental results. - Abstract: The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology. In the CRHDS the pulse flow from the pump into the hydraulic cylinder of the control rod hydraulic drive mechanism (CRHDM) is regulated by the integrated valve to perform the step motion of the reactor control rod. Transient flow occurs in the CRHDS during control rod step motion process which is studied by experiments. The time-history curves of flow rate, pressure and inner cylinder displacement were analyzed, and the results show that the water hammer pressure peak during the step-up motion is high, while there are no obvious pressure fluctuations in the corresponding step-down motion. In the step-up process, the pressure fluctuation amplitude increases with the increase of CRHDS driving pressure. The step-up time and the pressure increasing time before step-up decreases with the driving pressure. The step-up pressure increases with the driving pressure. In the step-down process, the step-down time, the step-down pressure and the pressure decreasing time before step-down do not change with the increase of the driving pressure. The experimental results lay the base for the working principle and vibration reduction analysis of the CRHDS and it’s also helpful for improvement of the working performance of the key facilities and instruments of the CRHDS loop.

  17. Experiment on smooth, circular cylinders in cross-flow in the critical Reynolds number regime

    Science.gov (United States)

    Miau, J. J.; Tsai, H. W.; Lin, Y. J.; Tu, J. K.; Fang, C. H.; Chen, M. C.

    2011-10-01

    Experiments were conducted for 2D circular cylinders at Reynolds numbers in the range of 1.73 × 105-5.86 × 105. In the experiment, two circular cylinder models made of acrylic and stainless steel, respectively, were employed, which have similar dimensions but different surface roughness. Particular attention was paid to the unsteady flow behaviors inferred by the signals obtained from the pressure taps on the cylinder models and by a hot-wire probe in the near-wake region. At Reynolds numbers pertaining to the initial transition from the subcritical to the critical regimes, pronounced pressure fluctuations were measured on the surfaces of both cylinder models, which were attributed to the excursion of unsteady flow separation over a large circumferential region. At the Reynolds numbers almost reaching the one-bubble state, it was noted that the development of separation bubble might switch from one side to the other with time. Wavelet analysis of the pressure signals measured simultaneously at θ = ±90° further revealed that when no separation bubble was developed, the instantaneous vortex-shedding frequencies could be clearly resolved, about 0.2, in terms of the Strouhal number. The results of oil-film flow visualization on the stainless steel cylinder of the one-bubble and two-bubble states showed that the flow reattachment region downstream of a separation bubble appeared not uniform along the span of the model. Thus, the three dimensionality was quite evident.

  18. Optical cylinder designs to increase the field of vision in the osteo-odonto-keratoprosthesis.

    Science.gov (United States)

    Hull, C C; Liu, C S; Sciscio, A; Eleftheriadis, H; Herold, J

    2000-12-01

    The single optical cylinders used in the osteo-odonto-keratoprosthesis (OOKP) are known to produce very small visual fields. Values of 40 degrees are typically quoted. The purpose of this paper is to present designs for new optical cylinders that significantly increase the field of view and therefore improve the visual rehabilitation of patients having an OOKP. Computer ray-tracing techniques were used to design and analyse improved one- and two-piece optical cylinders made from polymethyl methacrylate. All designs were required to have a potential visual acuity of 6/6 before consideration was given to the visual field and optimising off-axis image quality. Aspheric surfaces were used where this significantly improved off-axis image quality. Single optical cylinders, with increased posterior cylinder (intraocular) diameters, gave an increase in the theoretical visual field of 18% (from 76 degrees to 90 degrees) over current designs. Two-piece designs based on an inverted telephoto principle gave theoretical field angles over 120 degrees. Aspheric surfaces were shown to improve the off-axis image quality while maintaining a potential visual acuity of at least 6/6. This may well increase the measured visual field by improving the retinal illuminance off-axis. Results demonstrate that it is possible to significantly increase the theoretical maximum visual field through OOKP optical cylinders. Such designs will improve the visual rehabilitation of patients undergoing this procedure.

  19. Estimation of maximum pressure in small containments of PWR reactors due to loss of coolant accident in primary circuit; Estimativa da pressao maxima em contencoes de reatores PWR de pequeno porte devido a um acidente de perda de refrigerante no circuito primario

    Energy Technology Data Exchange (ETDEWEB)

    Mendes Neto, Teofilo [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Moreira, Joao Manoel Losada [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil)

    2000-07-01

    This work studies the problem of containment pressurization after a LOCA in reactors with small containment free volumes. The relationship between the reactor power and the containment free volume is described with the ratio between the volumes of the primary circuit and of the containment. The maximum pressure in a containment, following a LOCA, obtained after a correlation based on large containment PWR, is around 185 psia for a primary circuit and containment volumes ratio of 0.025. For the same problem, calculations with the CONTEMPT-LT code produced a maximum pressure of 162 psia. The behavior of the temperature after a LOCA to the containment, as a function of the ratio between the primary circuit and containment volume, is such that it increases reaching asymptotically to a maximum; differently, the pressure increases almost linearly with the ratio of volumes. (author)

  20. Maximum home systolic blood pressure is a useful indicator of arterial stiffness in patients with type 2 diabetes mellitus: post hoc analysis of a cross-sectional multicenter study.

    Science.gov (United States)

    Ushigome, Emi; Fukui, Michiaki; Hamaguchi, Masahide; Tanaka, Toru; Atsuta, Haruhiko; Mogami, Shin-ichi; Tsunoda, Sei; Yamazaki, Masahiro; Hasegawa, Goji; Nakamura, Naoto

    2014-09-01

    Maximum (max) home systolic blood pressure (HSBP) as well as mean HSBP or HSBP variability was reported to increase the predictive value of target organ damage. Yet, the association between max HSBP and target organ damage in patients with type 2 diabetes has never been reported. The aim of this study was to investigate the association between max HSBP and pulse wave velocity (PWV), a marker of arterial stiffness which in turn is a marker of target organ damage, in patients with type 2 diabetes. We assessed the relationship of mean HSBP or max HSBP to PWV, and compared area under the receiver-operating characteristic curve (AUC) of mean HSBP or max HSBP for arterial stiffness in 758 patients with type 2 diabetes. In the univariate analyses, age, duration of diabetes mellitus, body mass index, mean clinic systolic blood pressure (SBP), mean HSBP and max HSBP were associated with PWV. Multivariate linear regression analyses indicated that mean morning SBP (β=0.156, P=0.001) or max morning SBP (β=0.146, P=0.001) were significantly associated with PWV. AUC (95% CI) for arterial stiffness, defined as PWV equal to or more than 1800 cm per second, in mean morning SBP and max morning SBP were 0.622 (0.582-0.662; P<0.001) and 0.631 (0.591-0.670; P<0.001), respectively. Our findings implicate that max HSBP as well as mean HSBP was significantly associated with arterial stiffness in patients with type 2 diabetes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Thermodynamic consideration on self-regulating characteristics of cold neutron source with cylinder annulus type cold moderator cell

    International Nuclear Information System (INIS)

    Kawai, Takeshi; Yoshino, Hiroshi; Kawabata, Yuji; Hino, Masahiro

    2000-01-01

    Shapes of moderator baths of ORPHEE and NIST without bottom of inner cylinder, entering liquid from downward and push down the liquid by steam formed nuclear exotherm to fill inner part of the inner cylinder with steam, require to determine a number of parameters to be optimum to realize a state storing steam in inner cylinder and liquid in shell portion. Then, for a modulator bath with a structure shielding the inner cylinder from shell portion by preparing bottom without any pore and supplying steam into the cylinder through a steam return pipe mounted with pores at its upper portion. By such structure, a cold neutron source with self-balance-ability and capable of following output without time delaying. And, its liquid volume can also be controlled by system pressure. And that, as its structure is simple, it has another characteristic that its connection structure of transmission pipe portion with moderator bath portion. (G.K.)

  2. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Science.gov (United States)

    2010-10-01

    ...) Cross-head speed of the testing machine may not exceed 1/8 inch per minute during yield strength... increment of tensile strength above 50,000 psi to a maximum of four such increments. (n) Weld tests...: (1) Tensile test. A specimen must be cut from one cylinder of each lot of 200 or less, or welded test...

  3. Flow induced by a skewed vortex cylinder

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    The velocity field induced by a skewed vortex cylinder of longitudinal and tangential vorticity is derived in this chapter by direct integration of the Biot– Savart law. The derivation steps are provided in details. The results of Castles and Durham for the skewed semi-infinite cylinder....... The content of this chapter is based on the publication of the author entitled "Cylindrical vortex wake model: skewed cylinder, application to yawed or tilted rotors" [1]. Results from this chapter are applied: in Chap. 21 to model a wind turbine (or rotor) in yaw, in Chap. 22 to derive a new yaw...

  4. MONOMIALS AND BASIN CYLINDERS FOR NETWORK DYNAMICS.

    Science.gov (United States)

    Austin, Daniel; Dinwoodie, Ian H

    We describe methods to identify cylinder sets inside a basin of attraction for Boolean dynamics of biological networks. Such sets are used for designing regulatory interventions that make the system evolve towards a chosen attractor, for example initiating apoptosis in a cancer cell. We describe two algebraic methods for identifying cylinders inside a basin of attraction, one based on the Groebner fan that finds monomials that define cylinders and the other on primary decomposition. Both methods are applied to current examples of gene networks.

  5. Conversion of low BMEP 4-cylinder to high BMEP 2-cylinder large bore natural gas engine

    Science.gov (United States)

    Ladd, John

    There are more than 6,000 integral compressor engines in use on US natural gas pipelines, operating 24 hours a day, 365 days a year. Many of these engines have operated continuously for more than 50 years, with little to no modifications. Due to recent emission regulations at the local, state and federal levels much of the aging infrastructure requires retrofit technology to remain within compliance. The Engines and Energy Conversion Laboratory was founded to test these retrofit technologies on its large bore engine testbed (LBET). The LBET is a low brake mean effective pressure (BMEP) Cooper Bessemer GMVTF-4. Newer GMV models, constructed in 1980's, utilize turbocharging to increase the output power, achieving BMEP's nearly double that of the LBET. To expand the lab's testing capability and to reduce the LBET's running cost: material testing, in-depth modeling, and on engine testing was completed to evaluate the feasibility of uprating the LBET to a high BMEP two cylinder engine. Due to the LBET's age, the crankcase material properties were not known. Material samples were removed from engine to conduct an in-depth material analysis. It was found that the crankcase was cast out of a specific grade of gray iron, class 25 meehanite. A complete three dimensional model of the LBET's crankcase and power cylinders was created. Using historical engine data, the force inputs were created for a finite element analysis model of the LBET, to determine the regions of high stress. The areas of high stress were instrumented with strain gauges to iterate and validate the model's findings. Several test cases were run at the high and intermediate BMEP engine conditions. The model found, at high BMEP conditions the LBET would operate at the fatigue limit of the class 25 meehanite, operating with no factor of safety but the intermediate case were deemed acceptable.

  6. Effects of moisture migration on shrinkage, pore pressure and other concrete properties

    International Nuclear Information System (INIS)

    Chapman, D.A.; England, G.L.

    1977-01-01

    This work investigates the uniaxial migration of moisture in long, upright, limestone concrete cylinders, sealed at the base and sides, and open at the top. The design represents a section through a concrete pressure vessel wall. The cylinders are subjected to a sustained temperature difference between their ends, with maximum temperatures between 105 0 C and 200 0 C. Readings of pore pressure, water content and temperature are taken at various positions along the axis of the cylinders. In one cylinder transverse and longitudinal shrinkage readings are also recorded. The results for the cylinders show that moisture migration is away from the hot face of the specimens, causing reduction in both pore pressure and water content values in this region. The moisture migration creates a drying front which moves slowly up the specimens. Evaporation drying takes place from the unsealed end of the specimen. A drying front moves into the concrete and considerable weight loss is recorded as moisture escapes to the atmosphere. The rate of movement of the drying front is slower than that of the hot front and is proportional to the temperature difference between the top of the specimen and the surrounding atmosphere. In the shrinkage specimen, values of transverse and longitudinal shrinkage reflect the water content results. The specimen indicates that shrinkage occurs in a concrete pressure vessel, in the regions where moisture is lost. The restraint of the mass of concrete surrounding these regions sets up a three dimensional state of internal tensile stress. The areas into which the moisture migrates tend to swell, creating an internal stress situation, which is this

  7. Vortex-induced vibrations of a square cylinder under linear shear flow

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenjuan; Zhou, Dai; Han, Zhaolong [School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Tu, Jiahuang, E-mail: tujiahuang1982@163.com, E-mail: han.arkey@gmail.com [College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2017-04-15

    This paper investigates the numerical vortex-induced vibration (VIV) of a square cylinder which is connected to a 2-DOF mass-spring system and is immersed in the planar shear flow by employing a characteristic-based split (CBS) finite element method (FEM). The reduced mass of the square cylinder is M {sub r} = 2, while the reduced velocity, U {sub r}, is changed from 3 to 12 with an increment of Δ U {sub r} = 1. The effects of some key parameters on the cylinder dynamic responses, vibrating frequencies, the flow patterns as well as the energy transferred between the fluid and cylinder are revealed. In this study, the key parameters are selected as follows: shear ratio ( k  = 0, 0.05 and 0.1) and Reynolds numbers ( Re  = 80 and 160). Numerical results demonstrate that the X – Y trajectories of the cylinder mainly appear as a symmetrical figure ‘8’ in uniform flow ( k  = 0) and an unsymmetrical figure ‘8’ and ‘O’ in shear flows ( k  = 0.05 and 0.1). The maximum oscillation amplitudes of the square cylinder in both the inline and transverse directions have distinct characteristics compared to that of a circular cylinder. Two kinds of flow patterns, ‘2S’ and ‘P + S’, are mainly observed under the shear flow. Also, the mean values of the energy of the cylinder system increase with the reduced velocity, while the root mean square (rms) of the energy reaches its peak value at reduced velocity U {sub r} = 5. (paper)

  8. Failure Analysis of a Modern High Performance Diesel Engine Cylinder Head

    Directory of Open Access Journals (Sweden)

    Bingbin Guo

    2014-05-01

    Full Text Available This paper presents a failure analysis on a modern high performance diesel engine cylinder head made of gray cast iron. Cracks appeared intensively at the intersection of two exhaust passages in the cylinder head. The metallurgical examination was conducted in the crack origin zone and other zones. Meanwhile, the load state of the failure part of the cylinder head was determined through the Finite Element Analysis. The results showed that both the point of the maximum temperature and the point of the maximum thermal-mechanical coupling stress were not in the crack position. The excessive load was not the main cause of the failure. The large cooling rate in the casting process created an abnormal graphite zone that existed below the surface of the exhaust passage (about 1.1 mm depth, which led to the fracture of the cylinder head. In the fractured area, there were a large number of casting defects (dip sand, voids, etc. and inferior graphite structure (type D, type E which caused stress concentration. Moreover, high temperature gas entered the cracks, which caused material corrosion, material oxidization, and crack propagation. Finally, premature fracture of the cylinder head took place.

  9. A linear motor and compact cylinder-piston driver for left ventricular bypass.

    Science.gov (United States)

    Qian, K X

    1990-01-01

    A simple, portable, reliable and noise-free pneumatic driver has been developed. It consists of a linear motor attached to a cylinder piston, in one unit. The motor coil is directly wound on the cylinder, and the permanent magnet is fixed to the piston. As a continuous voltage square wave is applied to the coil, the cylinder reciprocates on the piston periodically, producing air pressure and vacuum alternately. In conjunction with a locally made diaphragm pump, the driver was tested in vitro and in vivo. Results demonstrated that the device could drive the diaphragm pump and so support the circulation of an experimental animal. The driver weighs 12 kg. For 200 mmHg air pressure and -80 mmHg vacuum the power consumed is 30 W. Its noise is about 30 dB, less than that of an artificial valve and pump.

  10. Unsteady cavity flow around a rectangular cylinder; Kakuchu mawari no hiteijo cavitation nagare

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, T.; Kaga, T.; Ota, T. [Tohoku University, Sendai (Japan). Faculty of Engineering; Mori, T. [Hachinohe Institute of Technology, Aomori (Japan)

    1995-08-25

    Unsteady cavity flow around a rectangular cylinder was observed using a high-speed camera. To clarify the correlation between the cavity behavior and fluid dynamic characteristics in the transitional region and supercavitation, fluctuating forces and surface pressures on the cylinder surface were recorded simultaneously. The tested cylinder has a critical width-to-height ration 2.8, in which the shear layer separated from the leading edge intermittently reattaches near the trailing edge. Bubbly cloud originating from the separated region near the leading edge causes fluctuation of cavity termination and induces large oscillations of fluid forces and pressures. As the cavitation number decreases, the low-frequency fluctuation of the cavity developing downstream of the rear surface increases in the fluid dynamic behavior. 24 refs., 12 figs.

  11. Numerical simulation of the pressure pulses produced by a pressure screen foil rotor

    International Nuclear Information System (INIS)

    Feng, M.; Ollivier-Gooch, C.; Gooding, R.W.; Olson, J.A.

    2003-01-01

    Pressure screening is the most industrially efficient and effective means of removing contaminants that degrade the appearance and strength of paper and fractionating fibres for selective treatments and specialty products. A critical design component of a screen is the rotor which produces pressure pulses on the screen cylinder surface to keep the screening apertures clear. To understand the effect of the key design and operating variables for a NACA 0012 foil rotor, a computational fluid dynamic (CFD) simulation tool was developed with FLUENT software, and the numerical results were compared with experimental measurements. The computational results of pressure pulses were shown to be in good agreement with experimental pressure measurements over a wide range of foil tip-speeds, clearances and angles of attack. In addition, it was shown that the magnitude of the pressure pulse peak increases as the rotating speed increases linearly with the square of tip-speed for all the angles of attack studied. The maximum negative pressure pulse occurred for the foil at 5 degrees angle of attack. Flow began to separate from foil surface near the screen plate beyond 10 degrees angle of attack. The positive pressure peak near the leading edge of the foil is completely eliminated for foils operating at a positive angle of attack. The magnitude of the negative pressure peak increased as clearance decreased. In addition to, and more important than, these specific results, we have shown that CFD is a viable tool for the optimal design and operation of rotors in industrial pressure screens. (author)

  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. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    We know from daily experience that many man-made structures consist of ..... The physical parameters of these composite cylinders following Eq. (38) are given in ... Titanium implants remain virtually unchanged in appearance, which offers ...

  14. Theory of interacting dislocations on cylinders.

    Science.gov (United States)

    Amir, Ariel; Paulose, Jayson; Nelson, David R

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  15. Cluster-based Reduced-order Modelling of Flow in the Wake of a Seal-vibrissa-shaped Cylinder

    Science.gov (United States)

    Wei, Zheng; Li, Qiliang; Yang, Zhigang; Xia, Chao; Shanghai Automotive Wind Tunnel Center Team

    2017-11-01

    The flow around a seal-vibrissa-shaped cylinder is numerically calculated using large eddy simulation (LES) at the Reynolds number of 20000, along with a smooth and a twisted cylinder for comparison. The mean drag coefficient of the seal-vibrissa-shaped cylinder is lower than that of the smooth and twisted cylinders, respectively. The fluctuating lift coefficient of the seal-vibrissa-shaped cylinder shows a substantial decrease compared with the smooth cylinder. The seal-vibrissa-shaped surface leads to more stable wake, longer vortex formation length, higher base pressure and three-dimensional separation. In addition, cluster-based reduced-order modelling (CROM) is performed to analyze phase-dependent variations of the wake flow, which discloses the complex unsteady behavior in different cross sections. Meanwhile, two flow regimes, anti-phased and in-phase-dominated vortex shedding, generated by the twisted cylinder and the seal-vibrissa-shaped cylinder are distinguished and extracted, their interrelationship are evaluated, and the question how forces are affected is answered. Supported by the National Key Research and Development Program of China (2016YFB1200503-04) and the Shanghai Automotive Wind Tunnel Technical Service Platform (16DZ2290400).

  16. Multiple Cylinder Free-Piston Stirling Machinery

    Science.gov (United States)

    Berchowitz, David M.; Kwon, Yong-Rak

    In order to improve the specific power of piston-cylinder type machinery, there is a point in capacity or power where an advantage accrues with increasing number of piston-cylinder assemblies. In the case of Stirling machinery where primary energy is transferred across the casing wall of the machine, this consideration is even more important. This is due primarily to the difference in scaling of basic power and the required heat transfer. Heat transfer is found to be progressively limited as the size of the machine increases. Multiple cylinder machines tend to preserve the surface area to volume ratio at more favorable levels. In addition, the spring effect of the working gas in the so-called alpha configuration is often sufficient to provide a high frequency resonance point that improves the specific power. There are a number of possible multiple cylinder configurations. The simplest is an opposed pair of piston-displacer machines (beta configuration). A three-cylinder machine requires stepped pistons to obtain proper volume phase relationships. Four to six cylinder configurations are also possible. A small demonstrator inline four cylinder alpha machine has been built to demonstrate both cooling operation and power generation. Data from this machine verifies theoretical expectations and is used to extrapolate the performance of future machines. Vibration levels are discussed and it is argued that some multiple cylinder machines have no linear component to the casing vibration but may have a nutating couple. Example applications are discussed ranging from general purpose coolers, computer cooling, exhaust heat power extraction and some high power engines.

  17. Dynamic Fracture Simulations of Explosively Loaded Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Carly W. [Univ. of California, Davis, CA (United States). Dept. of Civil and Environmental Engineering; Goto, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-11-30

    This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

  18. Collision Probabilities for Finite Cylinders and Cuboids

    Energy Technology Data Exchange (ETDEWEB)

    Carlvik, I

    1967-05-15

    Analytical formulae have been derived for the collision probabilities of homogeneous finite cylinders and cuboids. The formula for the finite cylinder contains double integrals, and the formula for the cuboid only single integrals. Collision probabilities have been calculated by means of the formulae and compared with values obtained by other authors. It was found that the calculations using the analytical formulae are much quicker and give higher accuracy than Monte Carlo calculations.

  19. Bristol cylinder. Vol. 3A - technical appraisal

    Energy Technology Data Exchange (ETDEWEB)

    1983-06-01

    A consultants' report is presented on a UK funded wave energy device known as the Bristol Cylinder. A detailed engineering appraisal is given for each component and aspects of the device including installation, power generation and maintenance. Finally the discounted cost of energy from the device is assessed. For all topics the views of the consultants are compared with those of the team developing the Bristol Cylinder and where discrepancies occur, these are explained and discussed.

  20. Pressure-Application Device for Testing Pressure Sensors

    Science.gov (United States)

    2002-01-01

    A portable pressure-application device has been designed and built for use in testing and calibrating piezoelectric pressure transducers in the field. The device generates pressure pulses of known amplitude. A pressure pulse (in contradistinction to a steady pressure) is needed because in the presence of a steady pressure, the electrical output of a piezoelectric pressure transducer decays rapidly with time. The device includes a stainless- steel compressed-air-storage cylinder of 500 cu cm volume. A manual hand pump with check valves and a pressure gauge are located at one end of the cylinder. A three-way solenoid valve that controls the release of pressurized air is located at the other end of the cylinder. Power for the device is provided by a 3.7-V cordless-telephone battery. The valve is controlled by means of a pushbutton switch, which activates a 5 V to +/-15 V DC-to-DC converter that powers the solenoid. The outlet of the solenoid valve is connected to the pressure transducer to be tested. Before the solenoid is energized, the transducer to be tested is at atmospheric pressure. When the solenoid is actuated by the push button, pressurized air from inside the cylinder is applied to the transducer. Once the pushbutton is released, the cylinder pressure is removed from the transducer and the pressurized air applied to the transducer is vented, bringing the transducer back to atmospheric pressure. Before this device was used for actual calibration, its accuracy was checked with a NIST (National Institute of Standards and Technology) traceable calibrator and commercially calibrated pressure transducers. This work was done by Wanda Solano of Stennis Space Center and Greg Richardson of Lockheed Martin Corp.

  1. Sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2008-01-01

    It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...

  2. Characterization of fluid forces exerted on a cylinder array oscillating laterally in axial flow

    International Nuclear Information System (INIS)

    Divaret, Lise

    2014-01-01

    This thesis presents an experimental and a numerical study of the fluid forces exerted on a cylinder or a cylinder array oscillating laterally in an axial flow. The parameters of the system are the amplitude, the oscillation frequency, the confinement and the length to diameter ratio of the cylinder. The objective is to determine the fluid damping created by the axial flow, i.e. the dissipative force. The industrial application of this thesis is the determination of the fluid damping of the fuel assemblies in the core of a nuclear power plant during an earthquake. The study focuses on the configurations where the oscillation velocity is small compared to the axial flow velocity. In a first part, we study the case of a cylinder with no confinement oscillating in axial flow. Two methods are used: a dynamical and a quasi-static approach. In dynamics, the damping rate is measured during free oscillations of the cylinder. In the quasi-static approach, the damping coefficient is calculated from the normal force measured on a yawed cylinder. The range of the small ratios between the oscillation and the axial flow velocities corresponds to a range of low yaw angle where the cylinder is in near-axial flow in statics. The case of a yawed cylinder has been studied both experimentally with experiments in a wind tunnel and numerically with CFD calculations. The analyses of the fluid forces shows that for yaw angles smaller than 5 degrees, a linear lift with the yaw angle creates the damping. The origin of the lift force is discussed from pressure and velocity measurements. The results of the quasi-static approach are compared to the results of the dynamical experiments. In a second part, an experimental study is performed on a rigid cylinder array made up of 40 cylinders oscillating in an axial flow. The normal force and the displacement of the cylinder array are measured simultaneously. The added mass and damping coefficient are calculated and their variation with the

  3. Revised model for the radiation force exerted by standing surface acoustic waves on a rigid cylinder

    Science.gov (United States)

    Liang, Shen; Chaohui, Wang

    2018-03-01

    In this paper, a model for the radiation force exerted by standing surface acoustic waves (SSAWs) on a rigid cylinder in inviscid fluids is extended to account for the dependence on the Rayleigh angle. The conventional model for the radiation force used in the SSAW-based applications is developed in plane standing waves, which fails to predict the movement of the cylinder in the SSAW. Our revised model reveals that, in the direction normal to the piezoelectric substrate on which the SSAW is generated, acoustic radiation force can be large enough to drive the cylinder even in the long-wavelength limit. Furthermore, the force in this direction can not only push the cylinder away, but also pull it back toward the substrate. In the direction parallel to the substrate, the equilibrium positions for particles can be actively tuned by changing Rayleigh angle. As an example considered in the paper, with the reduction of Rayleigh angle the equilibrium positions for steel cylinders in water change from pressure nodes to pressure antinodes. The model can thus be used in the design of SSAWs for particle manipulations.

  4. Analysis of composite hydrogen storage cylinders subjected to localized flame impingements

    Energy Technology Data Exchange (ETDEWEB)

    Hu, J.; Chen, J.; Sundararaman, S.; Chandrashekhara, K. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Chernicoff, William [US Department of Transportation, Washington, DC 20509 (United States)

    2008-06-15

    A comprehensive non-linear finite element model is developed for predicting the behavior of composite hydrogen storage cylinders subjected to high pressure and localized flame impingements. The model is formulated in an axi-symmetric coordinate system and incorporates with various sub-models to describe the behavior of the composite cylinder under extreme thermo-mechanical loadings. A heat transfer sub-model is employed to predict the temperature evolution of the composite cylinder wall and accounts for heat transport due to decomposition and mass loss. A composite decomposition sub-model described by Arrhenius's law is implemented to predict the residual resin content of thermal damaged area. A sub-model for material degradation is implemented to account for the loss of mechanical properties. A progressive failure model is adopted to detect various types of mechanical failure. These sub-models are implemented in ABAQUS commercial finite element code using user subroutines. Numerical results are presented for thermal damage, residual properties and profile of resin content in the cylinder. The developed model provides a useful tool for safe design and structural assessment of high pressure composite hydrogen storage cylinders. (author)

  5. Assessment of Reusing 14-Ton, Thin-Wall, Depleted UF6 Cylinders as LLW Disposal Containers

    International Nuclear Information System (INIS)

    O'Connor, D.G.; Poole, A.B.; Shelton, J.H.

    2000-01-01

    of 48 inches and nominally contain 14 tons (12.7 MT) of DUF 6 , were originally designed and fabricated for temporary storage of DUF 6 . They were fabricated from pressure-vessel-grade steels according to the provisions of the ASME Boiler and Pressure Vessel Code. Cylinders are stored in open yards at the three sites and, due to historical storage techniques, were subject to corrosion. Roughly 10,000 of the 14TTW cylinders are considered substandard due to corrosion and other structural anomalies caused by mishandling. This means that approximately 40,000 14TTW cylinders could be made available as containers for LLW disposal In order to demonstrate the use of 14TTW cylinders as LLW disposal containers, several qualifying tasks need to be performed. Two demonstrations are being considered using 14TTW cylinders--one demonstration using contaminated soil and one demonstration using U 3 O 8 . The objective of this report are to determine how much information is known that could be used to support the demonstrations, and how much additional work will need to be done in order to conduct the demonstrations. Information associated with the following four qualifying tasks are evaluated in this report

  6. An Analytic Approach to Cascade Control Design for Hydraulic Valve-Cylinder Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Hansen, Anders Hedegaard; Andersen, Torben O.

    2016-01-01

    , unfortunately not present in valve-operated hydraulic drives. This paper considers a cascade control approach for hydraulic valve-cylinder drives motivated by the fact that this may be applied to successfully suppress nonlinearities. The drive is pre-compensated utilizing a pressure updated inverse valve flow...

  7. Burst pressure investigation of filament wound type IV composite pressure vessel

    Science.gov (United States)

    Farhood, Naseer H.; Karuppanan, Saravanan; Ya, H. H.; Baharom, Mohamad Ariff

    2017-12-01

    Currently, composite pressure vessels (PVs) are employed in many industries such as aerospace, transportations, medical etc. Basically, the use of PVs in automotive application as a compressed natural gas (CNG) storage cylinder has been growing rapidly. Burst failure due to the laminate failure is the most critical failure mechanism for composite pressure vessels. It is predominantly caused by excessive internal pressure due to an overfilling or an overheating. In order to reduce fabrication difficulties and increase the structural efficiency, researches and studies are conducted continuously towards the proper selection of vessel design parameters. Hence, this paper is focused on the prediction of first ply failure pressure for such vessels utilizing finite element simulation based on Tsai-Wu and maximum stress failure criterions. The effects of laminate stacking sequence and orientation angle on the burst pressure were investigated in this work for a constant layered thickness PV. Two types of winding design, A [90°2/∓θ16/90°2] and B [90°2/∓θ]ns with different orientations of helical winding reinforcement were analyzed for carbon/epoxy composite material. It was found that laminate A sustained a maximum burst pressure of 55 MPa for a sequence of [90°2/∓15°16/90°2] while the laminate B returned a maximum burst pressure of 45 MPa corresponding to a stacking sequence of [90°2/±15°/90°2/±15°/90°2/±15° ....] up to 20 layers for a constant vessel thickness. For verification, a comparison was done with the literature under similar conditions of analysis and good agreement was achieved with a maximum difference of 4% and 10% for symmetrical and unsymmetrical layout, respectively.

  8. Results of ultrasonic testing evaluations on UF6 storage cylinders

    International Nuclear Information System (INIS)

    Lykins, M.L.

    1997-02-01

    The three site cylinder management program is responsible for the safe storage of the DOE owned UF 6 storage cylinders at PORTS, PGDP and at the K-25 site. To ensure the safe storage of the UF 6 in the cylinders, the structural integrity of the cylinders must be evaluated. This report represents the latest cylinder integrity investigation that utilized wall thickness evaluations to identify thinning due to atmospheric exposure

  9. NK-1 Removable Cryogenic Shroud (A Study of the Bimba Pneumatic Cylinder)

    International Nuclear Information System (INIS)

    Anderson, K.; Stefanescu, D.

    2003-01-01

    The Mark 1 Cryostat requires a cryogenic shroud that must be retracted immediately before firing the NIF laser. This paper evaluates a pneumatic cylinder that has been chosen to open and close the shroud. After a variety of motion control and vacuum compatibility experiments, we concluded that the Bimba feedback control cylinder may be used to retract the shroud with certain modifications to its control system and additional rod seals. The Mark I Cryostat is a system that allows fielding of a wide range of targets on the National Ignition Facility (NIF). The purpose is to have a system with the capability of controlling the target temperature between ∼10 and 300 K. While in the Target Chamber, a shroud must cover the cooled targets. This shroud allows the cold target to be shielded from condensable residual gasses in the target chamber. The removable shroud may be cooled to 80 K to provide a radiant shield for the target from the room temperature target chamber. The shroud must remain over the target until approximately one second before shot time, and then retract on command, without inducing vibration into the target. An actuation system design, which removes the shroud, is constrained by the size limitations of the MK-1, the need to build from low-activation materials, the need to operate in a vacuum, and the need for high reliability. The scheme for retracting the shroud that they investigated was a pressurized air cylinder. The pneumatic cylinder tested in our experiments was built by the Bimba Manufacturing Company. We thought it would be suitable for shroud retraction because its manufacturer claimed that its motion was smooth, highly accurate, controllable and the appropriate size for our needs. The pneumatic cylinder moves a piston by changing the gas pressure in the two sections of the cylinder on either side of the piston. The cylinder also uses the piston as a voltage potentiometer to determine the current position of the piston. This voltage is then

  10. An experimental study on the effects of high-pressure and multiple injection strategies on DI diesel engine emissions

    KAUST Repository

    Yang, Seung Yeon

    2013-03-25

    An experimental study on effects of high-pressure injections in conjunction with split fuel injections were conducted on an AVL single cylinder DI diesel engine. Various injection schemes were studied through the use of an electronically controlled, common rail injection system capable of injection pressures up to 200 MPa and a maximum of six injections per combustion event. Up to 100 MPa of the fuel injection pressure, the higher injection pressures create faster combustion rates that result in the higher in-cylinder gas temperatures as compared to conventional low-pressure fuel injection systems. When applying high-pressure injections, particulate emission reductions of up to 50% were observed with no change in hydrocarbon emissions, reductions of CO emissions and only slightly higher NOx emissions. Over 100 MPa, on the other hand, the higher injection pressures still reduced up to almost zero-level of particulate emission, at the same time that the NO emission is reduced greatly. Under these high-pressure injection conditions, strong correlations between soot and CO emissions were observed, which compete for the oxidizing OH species. Multiple or split high-pressure injections also investigated as a means to decrease particulate emissions. As a result, a four-split injection strategy resulted in a 55% reduction in particulates and with little or no penalty on NOx emissions. The high pressure split injection strategy with EGR was more effective in reducing particulate and CO emissions simultaneously. Copyright © 2013 SAE International and Copyright © 2013 TSAE.

  11. Acoustic scattering by multiple elliptical cylinders using collocation multipole method

    International Nuclear Information System (INIS)

    Lee, Wei-Ming

    2012-01-01

    This paper presents the collocation multipole method for the acoustic scattering induced by multiple elliptical cylinders subjected to an incident plane sound wave. To satisfy the Helmholtz equation in the elliptical coordinate system, the scattered acoustic field is formulated in terms of angular and radial Mathieu functions which also satisfy the radiation condition at infinity. The sound-soft or sound-hard boundary condition is satisfied by uniformly collocating points on the boundaries. For the sound-hard or Neumann conditions, the normal derivative of the acoustic pressure is determined by using the appropriate directional derivative without requiring the addition theorem of Mathieu functions. By truncating the multipole expansion, a finite linear algebraic system is derived and the scattered field can then be determined according to the given incident acoustic wave. Once the total field is calculated as the sum of the incident field and the scattered field, the near field acoustic pressure along the scatterers and the far field scattering pattern can be determined. For the acoustic scattering of one elliptical cylinder, the proposed results match well with the analytical solutions. The proposed scattered fields induced by two and three elliptical–cylindrical scatterers are critically compared with those provided by the boundary element method to validate the present method. Finally, the effects of the convexity of an elliptical scatterer, the separation between scatterers and the incident wave number and angle on the acoustic scattering are investigated.

  12. A Method for Turbocharging Four-Stroke Single Cylinder Engines

    Science.gov (United States)

    Buchman, Michael; Winter, Amos

    2014-11-01

    Turbocharging is not conventionally used with single cylinder engines due to the timing mismatch between when the turbo is powered and when it can deliver air to the cylinder. The proposed solution involves a fixed, pressurized volume - which we call an air capacitor - on the intake side of the engine between the turbocharger and intake valves. The capacitor acts as a buffer and would be implemented as a new style of intake manifold with a larger volume than traditional systems. This talk will present the flow analysis used to determine the optimal size for the capacitor, which was found to be four to five times the engine capacity, as well as its anticipated contributions to engine performance. For a capacitor sized for a one-liter engine, the time to reach operating pressure was found to be approximately two seconds, which would be acceptable for slowly accelerating applications and steady state applications. The air density increase that could be achieved, compared to ambient air, was found to vary between fifty percent for adiabatic compression and no heat transfer from the capacitor, to eighty percent for perfect heat transfer. These increases in density are proportional to, to first order, the anticipated power increases that could be realized. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1122374.

  13. 76 FR 1504 - Pipeline Safety: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure...

    Science.gov (United States)

    2011-01-10

    ... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No... Mitigation AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA); DOT. ACTION: Notice... system. To that end, the Hazardous Liquid and Gas Transmission Pipeline Integrity Management (IM...

  14. Dynamic Friction Performance of a Pneumatic Cylinder with Al2O3 Film on Cylinder Surface.

    Science.gov (United States)

    Chang, Ho; Lan, Chou-Wei; Wang, Hao-Xian

    2015-11-01

    A friction force system is proposed for accurately measuring friction force and motion properties produced by reciprocating motion of piston in a pneumatic cylinder. In this study, the proposed system is used to measure the effects of lubricating greases of different viscosities on the friction properties of pneumatic cylinder, and improvement of stick-slip motion for the cylinder bore by anodizing processes. A servo motor-driven ball screw is used to drive the pneumatic cylinder to be tested and to measure the change in friction force of the pneumatic cylinder. Experimental results show, that under similar test conditions, the lubricating grease with viscosity VG100 is best suited for measuring reciprocating motion of the piston of pneumatic cylinder. The wear experiment showed that, in the Al2O3 film obtained at a preset voltage 40 V in the anodic process, the friction coefficient and hardness decreased by 55% and increased by 274% respectively, thus achieving a good tribology and wear resistance. Additionally, the amplitude variation in the friction force of the pneumatic cylinder wall that received the anodizing treatment was substantially reduced. Additionally, the stick-slip motion of the pneumatic cylinder during low-speed motion was substantially improved.

  15. Baseline performance and emissions data for a single-cylinder, direct-injected diesel engine

    Science.gov (United States)

    Dezelick, R. A.; Mcfadden, J. J.; Ream, L. W.; Barrows, R. F.

    1983-01-01

    Comprehensive fuel consumption, mean effective cylinder pressure, and emission test results for a supercharged, single-cylinder, direct-injected, four-stroke-cycle, diesel test engine are documented. Inlet air-to-exhaust pressure ratios were varied from 1.25 to 3.35 in order to establish the potential effects of turbocharging techniques on engine performance. Inlet air temperatures and pressures were adjusted from 34 to 107 C and from 193 to 414 kPa to determine the effects on engine performance and emissions. Engine output ranged from 300 to 2100 kPa (brake mean effective pressure) in the speed range of 1000 to 3000 rpm. Gaseous and particulate emission rates were measured. Real-time values of engine friction and pumping loop losses were measured independently and compared with motored engine values.

  16. Mixed convection heat transfer simulation in a rectangular channel with a variable speed rotational cylinder

    Science.gov (United States)

    Khan, Md Imran; Billah, Md. Mamun; Rahman, Mohammed Mizanur; Hasan, Mohammad Nasim

    2017-12-01

    Numerical simulation of steady two-dimensional heat transfer in a rectangular channel with a centered variable speed cylinder has been performed in this paper. In this setup, an isoflux heater is placed at the bottom wall of the channel while the upper wall is kept isothermal with a low temperature. The cylinder's peripheral speed to maximum inlet fluid velocity ratio (ξ) is varied from 0.5 to 1.5 for both clockwise and anticlockwise rotational cases. Air has been considered as working fluid while other system parameters such as Grashof and Reynolds numbers are varied. The effects of rotational speed, Grashof and Reynolds numbers on the streamline pattern, isothermal lines, local and average Nusselt number are analyzed and presented. It is observed the cylinder's rotational direction and speed has a significant effect on the flow pattern, temperature distribution as well as heat transfer characteristics.

  17. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  18. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  19. Oscillatory Stokes Flow Past a Slip Cylinder

    Science.gov (United States)

    Palaniappan, D.

    2013-11-01

    Two-dimensional transient slow viscous flow past a circular cylinder with Navier slip boundary conditions is considered in the limit of low-Reynolds number. The oscillatory Stokes flow problem around a cylinder is solved using the stream function method leading to an analytic solution in terms of modified Bessel functions of the second kind. The corresponding steady-state behavior yields the familiar paradoxical result first detected by Stokes. It is noted that the two key parameters, viz., the frequency λ, and the slip coefficient ξ have a significant impact on the flow field in the vicinity of the cylinder contour. In the limit of very low frequency, the flow is dominated by a term containing a well-known biharmonic function found by Stokes that has a singular behavior at infinity. Local streamlines for small times show interesting flow patterns. Attached eddies due to flow separation - observed in the no-slip case - either get detached or pushed away from the cylinder surface as ξ is varied. Computed asymptotic results predict that the flow exhibits inviscid behavior far away from the cylinder in the frequency range 0 < λ << 1 . Although the frequency of oscillations is finite, our exact solutions reveal fairly rapid transitions in the flow domain. Research Enhancement grant, TAMUCC.

  20. Guided Circumferential Waves in Layered Poroelastic Cylinders

    Directory of Open Access Journals (Sweden)

    Shah S.A.

    2016-12-01

    Full Text Available The present paper investigates the propagation of time harmonic circumferential waves in a two-dimensional hollow poroelastic cylinder with an inner shaft (shaft-bearing assembly. The hollow poroelastic cylinder and inner shaft are assumed to be infinite in axial direction. The outer surface of the cylinder is stress free and at the interface, between the inner shaft and the outer cylinder, it is assumed to be free sliding and the interfacial shear stresses are zero, also the normal stress and radial displacements are continuous. The frequency equation of guided circumferential waves for a permeable and an impermeable surface is obtained. When the angular wave number vanish the frequency equation of guided circumferential waves for a permeable and an impermeable surface degenerates and the dilatational and shear waves are uncoupled. Shear waves are independent of the nature of surface. The frequency equation of a permeable and an impermeable surface for bore-piston assembly is obtained as a particular case of the model under consideration when the outer radius of the hollow poroelastic cylinder tends to infinity. Results of previous studies are obtained as a particular case of the present study. Nondimensional frequency as a function of wave number is presented graphically for two types of models and discussed. Numerical results show that, in general, the first modes are linear for permeable and impermeable surfaces and the frequency of a permeable surface is more than that of an impermeable surface.

  1. Prediction of external corrosion for steel cylinders

    International Nuclear Information System (INIS)

    Lyon, B.F.

    1997-02-01

    The US Department of Energy (DOE) currently manages the UF 6 Cylinder Program (the program). The program was formed to address the depleted-uranium hexafluoride (UF 6 ) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the K-25 site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1996a) delineates the requirements of the program. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1996b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF 6 Cylinder Program SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supersede those presented previously, as the quality of several of the datasets has improved

  2. UF{sub 6} cylinder fire test

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H. [Oak Ridge K-25 Site, Oak Ridge, TN (United States)

    1991-12-31

    With the increasing number of nuclear reactors for power generation, there is a comparable increase in the amount of UF{sub 6} being transported. Likewise, the probability of having an accident involving UF{sub 6}-filled cylinders also increases. Accident scenarios which have been difficult to assess are those involving a filled UF{sub 6} cylinder subjected to fire. A study is underway at the Oak Ridge K-25 Site, as part of the US DOE Enrichment Program, to provide empirical data and a computer model that can be used to evaluate various cylinder-in-fire scenarios. It is expected that the results will provide information leading to better handling of possible fire accidents as well as show whether changes should be made to provide different physical protection during shipment. The computer model being developed will be capable of predicting the rupture of various cylinder sizes and designs as well as the amount of UF{sub 6}, its distribution in the cylinder, and the conditions of the fire.

  3. Reducing pressure oscillations in discrete fluid power systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article investi...... investigates how cylinder pressure oscillations may be reduced by shaping the valve opening trajectory without the need for closed loop pressure feedback. Furthermore the energy costs of reducing pressure oscillations are investigated....

  4. Effect of longitudinal and transverse vibrations of an upstream square cylinder on vortex shedding behind two inline square cylinders

    International Nuclear Information System (INIS)

    Patil, Pratish P; Tiwari, Shaligram

    2009-01-01

    The characteristics of unsteady wakes behind a stationary square cylinder and another upstream vibrating square cylinder have been investigated numerically with the help of a developed computational code. The effect of longitudinal as well as transverse vibrations of the upstream cylinder is studied on the coupled wake between the two cylinders, which is found to control the vortex shedding behavior behind the downstream stationary cylinder. Computations are carried out for a fixed value of Reynolds number (Re = 200) and three different values of excitation frequencies of the upstream cylinder, namely less than, equal to and greater than the natural frequency of vortex shedding corresponding to flow past a stationary square cylinder. The vortex shedding characteristics of the unsteady wakes behind the vibrating and stationary cylinders are found to differ significantly for longitudinal and transverse modes of vibration of the upstream cylinder. The wake of the downstream stationary cylinder is found to depict a synchronization behavior with the upstream cylinder vibration. The spacing between the two cylinders has been identified to be the key parameter influencing the synchronization phenomenon. The effect of cylinder spacing on the wake synchronization and the hydrodynamic forces has been examined. In addition, a comparison of the drag forces for flow past transversely vibrating square and circular cylinders for similar amplitudes and frequencies of cylinder vibration has been presented while employing the tested computational code.

  5. ABOUT WAVEFORM OF BRAKING CYLINDER FILLING IN FREIGHT CARS

    Directory of Open Access Journals (Sweden)

    L. V. Ursuliak

    2016-04-01

    Full Text Available Purpose. As part of the scientific paper it is necessary to study the waveform impact of the braking cylinders filling on longitudinal train dynamics at different modes of braking. At this one should estimate the level of maximum longitudinal forces and braking distance size in freight cars of various lengths. Methodology. In this paper we attempt to approximate the actual diagram of braking cylinders filling with rational functions of varying degrees. In selection of coefficients in the required functions the highest values of the longitudinal forces and braking distances were used as controlled parameters. They were compared with similar values obtained as a result of experimental rides. The level of longitudinal forces and braking distances amount were evaluated by means of mathematical modeling of train longitudinal vibrations, caused by different braking modes. Findings. At mathematical modeling was assumed that the train consists of 60 uniform four-axle gondola cars, weight of 80 tons, equipped with air dispenser No. 483 included in the median operation, composite braking blocks, and one locomotive VL-8. Train before braking has been pre-stretched. Various types of pneumatic braking (emergency, full service and adjusting braking of the freight train on the horizontal section of the track were simulated. As the calculation results were obtained values of the longitudinal forces, braking distances amounts and reduction time in speed at various braking modes. Originality. Waveform impact of the braking cylinders filling on the longitudinal forces level and braking distances amount in freight trains were investigated. Also the longitudinal loading of freight trains at various pneumatic braking was investigated. Practical value. Obtained results can be used to assess the level of largest longitudinal forces and braking distances in the freight trains of different lengths by mathematical modeling of different braking modes.

  6. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  7. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  8. The Numerical Solution of the Navier-Stokes Equations for Laminar, Incompressible Flow past a Parabolic Cylinder

    NARCIS (Netherlands)

    Botta, E.F.F.; Dijkstra, D.; Veldman, A.E.P.

    1972-01-01

    The numerical method of solution for the semi-infinite flat plate has been extended to the case of the parabolic cylinder. Results are presented for the skin friction, the friction drag, the pressure and the pressure drag. The drag coefficients have been checked by means of an application of the

  9. Experimental investigation of flow characteristics around four square-cylinder arrays at subcritical Reynolds numbers

    Directory of Open Access Journals (Sweden)

    Mingyue Liu

    2015-09-01

    Full Text Available The Deep Draft Semi-Submersible (DDS concepts are known for their favourable vertical motion performance. However, the DDS may experience critical Vortex-Induced Motion (VIM stemming from the fluctuating forces on the columns. In order to investigate the current-induced excitation forces of VIM, an experimental study of flow characteristics around four square-section cylinders in a square configuration is presented. A number of column spacing ratios and array attack angles were considered to investigate the parametric influences. The results comprise flow patterns, drag and lift forces, as well as Strouhal numbers. It is shown that both the drag and lift forces acting on the cylinders are slightly different between the various L/D values, and the fluctuating forces peak at L/D = 4.14. The lift force of downstream cylinders reaches its maximum at around α = 15°. Furthermore, the flow around circular- section-cylinder arrays is also discussed in comparison with that of square cylinders.

  10. Corrosion of breached UF6 storage cylinders

    International Nuclear Information System (INIS)

    Barber, E.J.; Taylor, M.S.; DeVan, J.H.

    1993-01-01

    This paper describes the corrosion processes that occurred following the mechanical failure of two steel 14-ton storage cylinders containing depleted UF 6 . The failures both were traced to small mechanical tears that occurred during stacking of the cylinders. Although subsequent corrosion processes greatly extended the openings in the wall. the reaction products formed were quite protective and prevented any significant environmental insult or loss of uranium. The relative sizes of the two holes correlated with the relative exposure times that had elapsed from the time of stacking. From the sizes and geometries of the two holes, together with analyses of the reaction products, it was possible to determine the chemical reactions that controlled the corrosion process and to develop a scenario for predicting the rate of hydrolysis of UF 6 , the loss rate of HF, and chemical attack of a breached UF 6 storage cylinder

  11. A pneumatic cylinder driving polyhedron mobile mechanism

    Science.gov (United States)

    Ding, Wan; Kim, Sung-Chan; Yao, Yan-An

    2012-03-01

    A novel pneumatic cylinder driving polyhedron mobile mechanism is proposed in this paper. The mechanism is comprised of 5 tetrahedrons which includes a pneumatic cylinder in each edge. It locomotes by rolling and the rolling principle refers to the center of mass (CM) of the mechanism moved out of the supporting area and let it tip over through the controlling of the motion sequence of these cylinders. Firstly, the mathematical model is built to analysis the relation between the configuration and the CM of the mechanism. Then, a binary control strategy is developed to simplify and improve the control of this mobile mechanism. After that, dynamic simulation is performed to testify the analytical validity and feasibility of the rolling gaits. At last, a prototype is fabricated to achieve the rolling successfully to demonstrate the proposed concept.

  12. Proximity functions for general right cylinders

    International Nuclear Information System (INIS)

    Kellerer, A.M.

    1981-01-01

    Distributions of distances between pairs of points within geometrical objects, or the closely related proximity functions and geometric reduction factors, have applications to dosimetric and microdosimetric calculations. For convex bodies these functions are linked to the chord-length distributions that result from random intersections by straight lines. A synopsis of the most important relations is given. The proximity functions and related functions are derived for right cylinders with arbitrary cross sections. The solution utilizes the fact that the squares of the distances between two random points are sums of independently distributed squares of distances parallel and perpendicular to the axis of the cylinder. Analogous formulas are derived for the proximity functions or geometric reduction factors for a cylinder relative to a point. This requires only a minor modification of the solution

  13. Analysis of condensation on a horizontal cylinder with unknown wall temperature and comparison with the Nusselt model of film condensation

    Science.gov (United States)

    Bahrami, Parviz A.

    1996-01-01

    Theoretical analysis and numerical computations are performed to set forth a new model of film condensation on a horizontal cylinder. The model is more general than the well-known Nusselt model of film condensation and is designed to encompass all essential features of the Nusselt model. It is shown that a single parameter, constructed explicitly and without specification of the cylinder wall temperature, determines the degree of departure from the Nusselt model, which assumes a known and uniform wall temperature. It is also known that the Nusselt model is reached for very small, as well as very large, values of this parameter. In both limiting cases the cylinder wall temperature assumes a uniform distribution and the Nusselt model is approached. The maximum deviations between the two models is rather small for cases which are representative of cylinder dimensions, materials and conditions encountered in practice.

  14. Investigation of the thermal behavior of 2 1/2 ton cylinder protective overpack

    International Nuclear Information System (INIS)

    Park, S.H.

    1988-01-01

    UF 6 cylinders containing reactor grade enriched uranium are transported in protective overpacks. Recently, the design of the 2 1/2 ton UF 6 cylinder overpack was modified to insure the safety of the cylinder inside the overpack. Modifications include a continuous stainless steel liner from the outer surface to the inner surface of the overpack and step joints between the upper and lower halves of the overpack. The effects of a continuous stainless steel liner and moisture in the insulation layer of a UF 6 cylinder protective overpack were investigated with a numerical code. Results were compared with limited available field data. The purpose of comparing the numerical results with field data is to insure the validity of the numerical analysis and the physical properties used in the analysis. The study indicates that the continuous stainless steel liner did not influence the heat transfer rate much from the outer surface of the overpack to the 30B cylinder inside. The effect of step joints was not modeled due to the difficulty of quantifying the leakage rate through the gap. With a continuous stainless steel liner from the outside of the overpack to the inside, the overpack satisfies the thermal design criteria of protecting the cylinder inside for a minimum of 30 minutes when the overpack is exposed to a fire. The effect of moisture inside the insulation layer in the overpack is to reduce the energy to the cylinder with its high thermal capacity. The high pressure steam generated from the moisture will be relieved externally through the vent holes on the outer surface of the overpack. Although these holes are sealed after the overpack is dried, the plug sealing the holes will melt when the overpack is exposed to a fire

  15. Stress intensity factors of corner cracks in two nozzle-cylinder intersections

    International Nuclear Information System (INIS)

    Kobayashi, A.S.; Polvanich, N.; Emery, A.F.; Love, W.J.

    1977-01-01

    In a recent paper, the authors presented the stress-intensity-magnification factors of a quarter-elliptical surface crack in a quarter-infinite solid and a circular crack approaching a reentry corner in a three-quarter infinite solid. These stress-intensity-magnification factors were used together with a curvature-correction factor to estimate the stress-intensity factor of a corner crack at a nozzle-cylinder intersection. Through appropriate superposition of the above stress-intensity-magnification factors, stress-intensity factors for hypothetical corner cracks at a nozzle-cylinder intersection subjected to internal pressure and transient thermal-stress loadings can be obtained. A description of a computer code based on this procedure as well as its applications in analyzing two corner-crack problems at a nozzle-cylinder intersection are discussed in this paper

  16. Stress intensity factors of corner cracks in two nozzle-cylinder interactions

    International Nuclear Information System (INIS)

    Kobayashi, A.S.; Polvanich, N.; Emery, A.F.; Love, W.J.

    1977-01-01

    In a recent paper, the authors presented the stress-intensity-magnification factors of a quarter-elliptical surface crack in a quarter-infinite solid and a circular crack approaching a reentry corner in a three-quarter infinite solid. These stress-intensity-magnification factors were used together with a curvature-correction factor to estimate the stress-intensity factor of a corner crack at a nozzle-cylinder interaction. Through appropriate superposition of the above stress-intensity-magnification factors, stress-intensity factors for hypothetical corner cracks at a nozzle-cylinder intersection subjected to internal pressure and transient thermal-stress loadings can be obtained. A description of a computer code based on this procedure as well as its applications in analyzing two corner-crack probems at a nozzle-cylinder intersection are discussed in this paper. (Auth.)

  17. Schlieren measurements in the round cylinder of an optically accessible internal combustion engine.

    Science.gov (United States)

    Kaiser, Sebastian Arnold; Salazar, Victor Manuel; Hoops, Alexandra A

    2013-05-10

    This paper describes the design and experimental application of an optical system to perform schlieren measurements in the curved geometry of the cylinder of an optically accessible internal combustion engine. Key features of the system are a pair of cylindrical positive meniscus lenses, which keep the beam collimated while passing through the unmodified, thick-walled optical cylinder, and a pulsed, high-power light-emitting diode with narrow spectral width. In combination with a high-speed CMOS camera, the system is used to visualize the fuel jet after injection of hydrogen fuel directly into the cylinder from a high-pressure injector. Residual aberrations, which limit the system's sensitivity, are characterized experimentally and are compared to the predictions of ray-tracing software.

  18. Large eddy simulation of turbulent flow for wall mounted cantilever cylinders of aspect ratio 6 and 10

    International Nuclear Information System (INIS)

    Afgan, Imran; Moulinec, Charles; Prosser, Robert; Laurence, Dominique

    2007-01-01

    The flow structure around wall mounted circular cylinders of finite heights is numerically investigated via large eddy simulation (LES). The cylinder aspect ratios (AR) are 6 and 10 and the Reynolds number (Re) based on cylinder diameter and free stream velocity is 20,000 for both cases. The cantilever cylinder mounted on a flat plate is chosen since it gives insight into two entirely different flow phenomena; the tip effects of the free end (which show strong three-dimensional wake structures) and the base or junction effects (due to interaction of flow between the cylinder and the flat plate). Regular vortex shedding is found in the wake of the higher aspect ratio case as was anticipated, along with a strong downwash originating from the flow over the free end of the cylinder, whereas irregular and intermittent vortex shedding occurs in the lower aspect ratio case. Pressure distributions are computed along the length of the cylinder and compared to experimental results. Lift and drag values are also computed, along with Strouhal numbers

  19. Electromagnetic Invisibility of Elliptic Cylinder Cloaks

    International Nuclear Information System (INIS)

    Kan, Yao; Chao, Li; Fang, Li

    2008-01-01

    Structures with unique electromagnetic properties are designed based on the approach of spatial coordinate transformations of Maxwell's equations. This approach is applied to scheme out invisible elliptic cylinder cloaks, which provide more feasibility for cloaking arbitrarily shaped objects. The transformation expressions for the anisotropic material parameters and the field distribution are derived. The cloaking performances of ideal and lossy elliptic cylinder cloaks are investigated by finite element simulations. It is found that the cloaking performance will degrade in the forward direction with increasing loss. (fundamental areas of phenomenology (including applications))

  20. Cylinder wakes in flowing soap films

    International Nuclear Information System (INIS)

    Vorobieff, P.; Ecke, R.E.; Vorobieff, P.

    1999-01-01

    We present an experimental characterization of cylinder wakes in flowing soap films. From instantaneous velocity and thickness fields, we find the vortex-shedding frequency, mean-flow velocity, and mean-film thickness. Using the empirical relationship between the Reynolds and Strouhal numbers obtained for cylinder wakes in three dimensions, we estimate the effective soap-film viscosity and its dependence on film thickness. We also compare the decay of vorticity with that in a simple Rankine vortex model with a dissipative term to account for air drag. copyright 1999 The American Physical Society

  1. Energy balance during underwater implosion of ductile metallic cylinders.

    Science.gov (United States)

    Chamberlin, Ryan E; Guzas, Emily L; Ambrico, Joseph M

    2014-11-01

    Energy-based metrics are developed and applied to a numerical test case of implosion of an underwater pressure vessel. The energy metrics provide estimates of the initial energy in the system (potential energy), the energy released into the fluid as a pressure pulse, the energy absorbed by the imploding structure, and the energy absorbed by air trapped within the imploding structure. The primary test case considered is the implosion of an aluminum cylinder [diameter: 2.54 cm (1 in.), length: 27.46 cm (10.81 in.)] that collapses flat in a mode-2 shape with minimal fracture. The test case indicates that the structure absorbs the majority (92%) of the initial energy in the system. Consequently, the energy emitted as a pressure pulse into the fluid is a small fraction, approximately 5%, of the initial energy. The energy absorbed by the structure and the energy emitted into the fluid are calculated for additional simulations of underwater pressure vessel implosions. For all cases investigated, there is minimal fracture in the collapse, the structure absorbs more than 80% of the initial energy of the system, and the released pressure pulse carries away less than 6% of the initial energy.

  2. Flow over an inline oscillating circular cylinder in the wake of a stationary circular cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yang; Zhu, Keqiang, E-mail: zhukeqiang@nbu.edu.cn [Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211 (China)

    2017-02-15

    Flow interference between an upstream stationary cylinder and an inline oscillating cylinder is studied with the lattice Boltzmann method. With a fixed Reynolds number Re  = 100 and pitch ratio L / D  = 4, the effects of oscillation amplitude A / D  = [0.25, 1] and frequency f {sub e}/ f {sub s} = [0.5, 2] are investigated. The wake response state is categorized into lock-in and non-lock-in. The lock-in zone in the bifurcation diagram of amplitude versus frequency is discontinuous. Response states of upstream and downstream wakes are similar under the conditions of small amplitude or low frequency. However, with large oscillating parameters, the two wakes are prone to be in different states as the flow field becomes irregular. Two distinct flow regimes have been identified, i.e., single-cylinder and two-cylinder shedding regimes. The presence of single-cylinder shedding regime is attributed to the low shedding frequency of the downstream cylinder at large amplitude. Hydrodynamic forces of the oscillating tandem system are discussed. The results reveal that forces on the two cylinders behave differently and that the absence of vortices in the gap flow significantly reduces the forces exerting on the tandem system. (paper)

  3. UF{sub 6} cylinder inspections at PGDP

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, G.W.; Whinnery, W.N. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Routine inspections of all UF{sub 6} cylinders at the Paducah Gaseous Diffusion Plant have been mandated by the Department of Energy. A specific UF{sub 6} cylinder inspection procedure for what items to inspect and training for the operators prior to inspection duty are described. The layout of the cylinder yards and the forms used in the inspections are shown. The large number of cylinders (>30,000) to inspect and the schedule for completion on the mandated time table are discussed. Results of the inspections and the actions to correct the deficiencies are explained. Future inspections and movement of cylinders for relocation of certain cylinder yards are defined.

  4. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  5. Engine control system having pressure-based timing

    Science.gov (United States)

    Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL

    2011-10-04

    A control system for an engine having a first cylinder and a second cylinder is disclosed having a first engine valve movable to regulate a fluid flow of the first cylinder and a first actuator associated with the first engine valve. The control system also has a second engine valve movable to regulate a fluid flow of the second cylinder and a sensor configured to generate a signal indicative of a pressure within the first cylinder. The control system also has a controller that is in communication with the first actuator and the sensor. The controller is configured to compare the pressure within the first cylinder with a desired pressure and selectively regulate the first actuator to adjust a timing of the first engine valve independently of the timing of the second engine valve based on the comparison.

  6. Experimental Evaluation of a Method for Turbocharging Four-Stroke, Single Cylinder, Internal Combustion Engines

    Science.gov (United States)

    Buchman, Michael; Winter, Amos

    2015-11-01

    Turbocharging an engine increases specific power, improves fuel economy, reduces emissions, and lowers cost compared to a naturally aspirated engine of the same power output. These advantages make turbocharging commonplace for multi-cylinder engines. Single cylinder engineers are not commonly turbocharged due to the phase lag between the exhaust stroke, which powers the turbocharger, and the intake stroke, when air is pumped into the engine. Our proposed method of turbocharging single cylinder engines is to add an ``air capacitor'' to the intake manifold, an additional volume that acts as a buffer to store compressed air between the exhaust and intake strokes, and smooth out the pressure pulses from the turbocharger. This talk presents experimental results from a single cylinder, turbocharged diesel engine fit with various sized air capacitors. Power output from the engine was measured using a dynamometer made from a generator, with the electrical power dissipated with resistive heating elements. We found that intake air density increases with capacitor size as theoretically predicted, ranging from 40 to 60 percent depending on heat transfer. Our experiment was able to produce 29 percent more power compared to using natural aspiration. These results validated that an air capacitor and turbocharger may be a simple, cost effective means of increasing the power density of single cylinder engines.

  7. An Improved Lubrication Model between Piston Rings and Cylinder Liners with Consideration of Liner Dynamic Deformations

    Directory of Open Access Journals (Sweden)

    Guoxing Li

    2017-12-01

    Full Text Available The friction pair of piston rings and cylinder liner is one of the most important friction couplings in an internal combustion engine. It influences engine efficiency and service life. Under the excitation of piston slaps, the dynamic deformation of cylinder liner is close to the surface roughness magnitudes, which can affect the friction and lubrication performance between the piston rings and cylinder assemblies. To investigate the potential influences of structural deformations to tribological behaviours of cylinder assemblies, the dynamic deformation of the inner surface due to pistons slaps is obtained by dynamic simulations, and then coupled into an improved lubrication model. Different from the traditional lubrication model which takes the pressure stress factor and shear stress factor to be constant, the model proposed in this paper calculated these factors in real time using numerical integration to achieve a more realistic simulation. Based on the improved piston rings and cylinder liner lubrication model, the minimum oil film thickness and friction force curves are obtained for an entire work cycle. It shows that the friction force obtained from the improved model manifests clear oscillations in each stoke, which is different from the smoothed profiles predicted traditionally. Moreover, the average amplitude of the friction forces also shows clear reduction.

  8. Rolling cylinder phase 1: proof of concept and first optimization

    Energy Technology Data Exchange (ETDEWEB)

    Margheritini, L.; Taraborrelli, V.

    2011-07-15

    The Rolling Cylinder is an innovative wave energy device at first stage of development at the time this report is created. The report is aimed at the first stage testing of the Rolling Cylinder wave energy device. This phase includes tests in regular waves and irregular waves, realized in two different set of tests. The optimized short model for the rolling cylinder resulted to have 7 sets of fins with relative distance between two consecutive sets = 0.20 m, 6 fins par set with a thickness of 0.75 mm and a draft d = 0.36 m that features half blade emerging from mean water level. In this case the maximum efficiencies were: 1) 8.7% for RW3. 2) 7.3% for RW4. 3) 6.3% for RW5. These results under typical regular waves (RW3-5) were very close to the results with 4 sets of fins with relative distance between two consecutive sets = 0.40 m, 6 fins par set, 0.75 mm thickness and draft = 0.36 m: 1) 7.2% for RW3. 2) 6.9% for RW4. 3) 6.2% for RW5. It must be noticed that the short model does not have the necessary length to perform optimally under the target wave conditions. The optimal device length has been calculated to be comparable to the wave length of the most energetic/probable wave conditions, i.e. RW3 and RW4. Under this consideration, the short model is only 1/3 of the total length of a complete device that should then be = 4.2 m (105 m in full scale). A first rough estimation of the power production for the rolling cylinder has been conducted using the results from regular wave tests. It has been concluded that for a fixed device (not floating), 105 m long with 23 sets of fins, 6 fins par set, draft of 9 m, similar geometry and fin's elasticity than the model tested in the present report, as well as possibility of adjusting the load to the incoming wave condition (gearing), the yearly energy production of 241 MWh/y (minus the losses in the power take off system), corresponding to a mechanic efficiency of 19%. Result must be validated with irregular wave tests

  9. Dynamic modelling of the expansion cylinder of an open Joule cycle Ericsson engine: A bond graph approach

    International Nuclear Information System (INIS)

    Creyx, M.; Delacourt, E.; Morin, C.; Desmet, B.

    2016-01-01

    A dynamic model using the bond graph formalism of the expansion cylinder of an open Joule cycle Ericsson engine intended for a biomass-fuelled micro-CHP system is presented. Dynamic phenomena, such as the thermodynamic evolution of air, the instantaneous air mass flow rates linked to pressure drops crossing the valves, the heat transferred through the expansion cylinder wall and the mechanical friction losses, are included in the model. The influence on the Ericsson engine performances of the main operating conditions (intake air pressure and temperature, timing of intake and exhaust valve closing, rotational speed, mechanical friction losses and heat transfer at expansion cylinder wall) is studied. The operating conditions maximizing the performances of the Ericsson engine used in the a biomass-fuelled micro-CHP unit are an intake air pressure between 6 and 8 bar, a maximized intake air temperature, an adjustment of the intake and exhaust valve closing corresponding to an expansion cycle close to the theoretical Joule cycle, a rotational speed close to 800 rpm. The heat transfer at the expansion cylinder wall reduces the engine performances. - Highlights: • A bond graph dynamic model of the Ericsson engine expansion cylinder is presented. • Dynamic aspects are modelled: pressure drops, friction losses, wall heat transfer. • Influent factors and phenomena on the engine performances are investigated. • Expansion cycles close to the theoretical Joule cycle maximize the performances. • The heat transfer at the expansion chamber wall reduces the performances.

  10. The use of thick-walled hollow cylinder creep tests for evaluating flow criteria for rock salt

    International Nuclear Information System (INIS)

    Morgan, H.S.; Wawersik, W.R.

    1990-01-01

    Finite element simulations of two laboratory creep tests on thick-walled hollow cylinders of rock salt are evaluated to determine if such bench-scale experiments can be used to establish applicability of either von Mises or Tresca stress measures and associated flow conditions. In the tests, the cylinders were loaded axially and pressurized both internally and externally to produce stress fields similar to those found around underground excavations in rock salt. Several different loading stages were used in each test. The simulations show that for each of two creep models studied, quite different deformations of the cylinders are predicted with the Mises and Tresca flow criteria, especially if friction between the cylinders and axial loading platens is ignored. When friction is included in the simulations, the differences in deformation are changed but are sill clearly distinguishable. 10 refs., 10 figs

  11. Control of 12-Cylinder Camless Engine with Neural Networks

    Directory of Open Access Journals (Sweden)

    Ashhab Moh’d Sami

    2017-01-01

    Full Text Available The 12-cyliner camless engine breathing process is modeled with artificial neural networks (ANN’s. The inputs to the net are the intake valve lift (IVL and intake valve closing timing (IVC whereas the output of the net is the cylinder air charge (CAC. The ANN is trained with data collected from an engine simulation model which is based on thermodynamics principles and calibrated against real engine data. A method for adapting single-output feed-forward neural networks is proposed and applied to the camless engine ANN model. As a consequence the overall 12-cyliner camless engine feedback controller is upgraded and the necessary changes are implemented in order to contain the adaptive neural network with the objective of tracking the cylinder air charge (driver’s torque demand while minimizing the pumping losses (increasing engine efficiency. All the needed measurements are extracted only from the two conventional and inexpensive sensors, namely, the mass air flow through the throttle body (MAF and the intake manifold absolute pressure (MAP sensors. The feedback controller’s capability is demonstrated through computer simulation.

  12. Maximum likely scale estimation

    DEFF Research Database (Denmark)

    Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo

    2005-01-01

    A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...

  13. Robust Maximum Association Estimators

    NARCIS (Netherlands)

    A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)

    2017-01-01

    textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation

  14. Spin-Up in a Rectangular Cylinder

    Science.gov (United States)

    1993-12-01

    BEST QUALITY AVAILABLE. THE COPY FURNISHED TO DTIC CONTAINED A SIGNIFICANT NUMBER OF COLOR PAGES WHICH DO NOT REPRODUCE LEGIBLY ON BLACK AND WRITE ...cylinder by scaling as follows: I I IElt , and p = E’,X, 3.22 where we have scaled the radial and vertical flow to be higher order in Ekman number than the

  15. Stability analysis of cylinders with circular cutouts

    Science.gov (United States)

    Almroth, B. O.; Brogan, F. A.; Marlowe, M. B.

    1973-01-01

    The stability of axially compressed cylinders with circular cutouts is analyzed numerically. An extension of the finite-difference method is used which removes the requirement that displacement components be defined in the directions of the grid lines. The results of this nonlinear analysis are found to be in good agreement with earlier experimental results.

  16. Anomalous skin-effect in tin cylinders

    NARCIS (Netherlands)

    van de Klundert, L.J.M.; Gijsbertse, E.A.; van der Marel, L.C.

    1972-01-01

    The susceptibilities of three Sn-cylinders have been measured at a temperature slightly below Tc and in an external magnetic field just below Hc(T). The results are compared with calculations for a flat plate. From this the d.c. conductivity, the mean free path and the reflectivity-factor, have been

  17. Self-contact for rods on cylinders

    NARCIS (Netherlands)

    Heijden, van der G.H.M.; Peletier, M.A.; Planqué, R.

    2006-01-01

    We study self-contact phenomena in elastic rods that are constrained to lie on a cylinder. By choosing a particular set of variables to describe the rod centerline the variational setting is made particularly simple: the strain energy is a second-order functional of a single scalar variable, and the

  18. Self-contact for rods on cylinders

    NARCIS (Netherlands)

    G.H.M. van der Heijden; M.A. Peletier (Mark); R. Planqué (Robert)

    2004-01-01

    textabstractWe study self-contact phenomena in elastic rods that are constrained to lie on a cylinder. By choosing a particular set of variables to describe the rod centerline the variational setting is made particularly simple: the strain energy is a second-order functional of a single scalar

  19. Self-contact for rods on cylinders

    NARCIS (Netherlands)

    Heijden, van der G.H.M.; Peletier, M.A.; Planqué, R.

    2004-01-01

    We study self-contact phenomena in elastic rods that are constrained to lie on a cylinder. By choosing a particular set of variables to describe the rod centerline the variational setting is made particularly simple: the strain energy is a second-order functional of a single scalar variable, and the

  20. Magnetohydrodynamic flow past a circular cylinder

    International Nuclear Information System (INIS)

    Swarup, S.; Sinha, P.C.

    1977-01-01

    This paper deals with the slow-flow problem of an incompressible, viscous, electrically conducting fluid past a circular cylinder in an alignment magnetic field. The solutions for the velocity and magnetic fields as sought by the method of matched asymptotic expansions under the assumptions R,Rsub(m) 2 ) and O(R/log M), respectively. (Auth.)

  1. The Experience Cylinder, an immersive interactive platform

    DEFF Research Database (Denmark)

    Andreasen, Troels; Gallagher, John Patrick; Møbius, Nikolaj

    2011-01-01

    This paper describes the development of an experimental interactive installation, a so-called "experience cylinder", intended as a travelogue and developed specifically to provide a narrative about the Viking ship Sea Stallion’s (Havhingst) voyage from Roskilde to Dublin and back. The installation...

  2. The capillary interaction between two vertical cylinders

    KAUST Repository

    Cooray, Himantha; Cicuta, Pietro; Vella, Dominic

    2012-01-01

    surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite

  3. Interface dilation : the overflowing cylinder technique

    NARCIS (Netherlands)

    Bergink - Martens, D.J.M.

    1993-01-01

    A pure steady-state dilation of a liquid interface, either liquid-air or water-oil, can be accomplished far from equilibrium by means of the overflowing cylinder technique. The resulting dynamic surface tension data correlate well with characteristic parameters of processes like foaming,

  4. Reshaping the perfect electrical conductor cylinder arbitrarily

    International Nuclear Information System (INIS)

    Chen Huanyang; Zhang Xiaohe; Luo Xudong; Ma Hongru; Chan Cheting

    2008-01-01

    A general method is proposed to design a cylindrical cloak, concentrator and superscatterer with an arbitrary cross section. The method is demonstrated by the design of a perfect electrical conductor (PEC) reshaper which is able to reshape a PEC cylinder arbitrarily by combining the concept of cloak, concentrator and superscatterer together. Numerical simulations are performed to demonstrate its properties.

  5. Lectures on controlled topology: Mapping cylinder neighborhoods

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, F [Department of Mathematics, Virginia Tech, Blacksburg, VA (United States)

    2002-08-15

    The existence theorem for mapping cylinder neighborhoods is discussed as a prototypical example of controlled topology and its applications. The first of a projected series developed from lectures at the Summer School on High-Dimensional Topology, Trieste, Italy 2001. (author)

  6. Lectures on controlled topology: Mapping cylinder neighborhoods

    International Nuclear Information System (INIS)

    Quinn, F.

    2002-01-01

    The existence theorem for mapping cylinder neighborhoods is discussed as a prototypical example of controlled topology and its applications. The first of a projected series developed from lectures at the Summer School on High-Dimensional Topology, Trieste, Italy 2001. (author)

  7. Breached cylinder incident at the Portsmouth gaseous diffusion plant

    Energy Technology Data Exchange (ETDEWEB)

    Boelens, R.A. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    On June 16, 1990, during an inspection of valves on partially depleted product storage cylinders, a 14-ton partially depleted product cylinder was discovered breached. The cylinder had been placed in long-term storage in 1977 on the top row of Portsmouth`s (two rows high) storage area. The breach was observed when an inspector noticed a pile of green material along side of the cylinder. The breach was estimated to be approximately 8- inches wide and 16-inches long, and ran under the first stiffening ring of the cylinder. During the continuing inspection of the storage area, a second 14-ton product cylinder was discovered breached. This cylinder was stacked on the bottom row in the storage area in 1986. This breach was also located adjacent to a stiffening ring. This paper will discuss the contributing factors of the breaching of the cylinders, the immediate response, subsequent actions in support of the investigation, and corrective actions.

  8. Investigation on carbon nanomaterials: Coaxial CNT-cylinders and ...

    Indian Academy of Sciences (India)

    Wintec

    carbon cylinders of CNT stacks have been formed directly inside the quartz tube. Another study is ... producing CNTs have been devised including electric arc evaporation ... process of coaxial carbon cylinder have already been de- scribed by ...

  9. Large-eddy simulation of flow over a grooved cylinder up to transcritical Reynolds numbers

    KAUST Repository

    Cheng, W.

    2017-11-27

    We report wall-resolved large-eddy simulation (LES) of flow over a grooved cylinder up to the transcritical regime. The stretched-vortex subgrid-scale model is embedded in a general fourth-order finite-difference code discretization on a curvilinear mesh. In the present study grooves are equally distributed around the circumference of the cylinder, each of sinusoidal shape with height , invariant in the spanwise direction. Based on the two parameters, and the Reynolds number where is the free-stream velocity, the diameter of the cylinder and the kinematic viscosity, two main sets of simulations are described. The first set varies from to while fixing . We study the flow deviation from the smooth-cylinder case, with emphasis on several important statistics such as the length of the mean-flow recirculation bubble , the pressure coefficient , the skin-friction coefficient and the non-dimensional pressure gradient parameter . It is found that, with increasing at fixed , some properties of the mean flow behave somewhat similarly to changes in the smooth-cylinder flow when is increased. This includes shrinking and nearly constant minimum pressure coefficient. In contrast, while the non-dimensional pressure gradient parameter remains nearly constant for the front part of the smooth cylinder flow, shows an oscillatory variation for the grooved-cylinder case. The second main set of LES varies from to with fixed . It is found that this range spans the subcritical and supercritical regimes and reaches the beginning of the transcritical flow regime. Mean-flow properties are diagnosed and compared with available experimental data including and the drag coefficient . The timewise variation of the lift and drag coefficients are also studied to elucidate the transition among three regimes. Instantaneous images of the surface, skin-friction vector field and also of the three-dimensional Q-criterion field are utilized to further understand the dynamics of the near-surface flow

  10. Nonlinear bending and collapse analysis of a poked cylinder and other point-loaded cylinders

    International Nuclear Information System (INIS)

    Sobel, L.H.

    1983-06-01

    This paper analyzes the geometrically nonlinear bending and collapse behavior of an elastic, simply supported cylindrical shell subjected to an inward-directed point load applied at midlength. The large displacement analysis results for this thin (R/t = 638) poked cylinder were obtained from the STAGSC-1 finite element computer program. STAGSC-1 results are also presented for two other point-loaded shell problems: a pinched cylinder (R/t = 100), and a venetian blind (R/t = 250)

  11. Inner and outer cylinders of the CMS vacuum tank.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the already installed outer cylinder, through which this photo was taken.

  12. Experimental Study of 3D Movement in Cushioning of Hydraulic Cylinder

    Directory of Open Access Journals (Sweden)

    Antonio Algar

    2017-05-01

    Full Text Available A double acting cylinder operation has been fully monitored in its key functional parameters, focused on characterization of end-of-stroke cushioning and starting phases. Being the cylinder performance reliant in the piston constructive geometry, the number and location of piston circumferential grooves is a significant parameter affecting the internal cushioning system performance. An eddy current displacement sensor assembled in the piston allows assessment of piston radial displacement inside the cylinder tube, which is directly related with the studied operating phases. Due to such 3D displacements, the piston becomes as an active and self-adjusting element along the functional cycle of the cylinder. Mechanical joints orientation and operating pressure are also relevant parameters affecting piston radial displacement and, thus, the cushioning and starting performance. Computational Fluid Dynamics (CFD results confirm the observed functional role of the perimeter grooves; the flow and pressure distributions, where develops a significant radial force, are also in accordance with the registered radial displacement.

  13. Effects of Atwood number on shock focusing in shock-cylinder interaction

    Science.gov (United States)

    Ou, Junfeng; Ding, Juchun; Luo, Xisheng; Zhai, Zhigang

    2018-02-01

    The evolution of shock-accelerated heavy-gas cylinder surrounded by the air with different Atwood numbers (A_t=0.28, 0.50, 0.63) is investigated, concentrating on shock focusing and jet formation. Experimentally, a soap film technique is used to generate an ideal two-dimensional discontinuous gas cylinder with a clear surface, which can guarantee the observation of shock wave movements inside the cylinder. Different Atwood numbers are realized by different mixing ratios of SF_6 and air inside the cylinder. A high-speed schlieren system is adopted to capture the shock motions and jet morphology. Numerical simulations are also performed to provide more information. The results indicate that an inward jet is formed for low Atwood numbers, while an outward jet is generated for high Atwood numbers. Different Atwood numbers will lead to the differences in the relative velocities between the incident shock and the refraction shock, which ultimately results in the differences in shock competition near the downstream pole. The morphology and feature of the jet are closely associated with the position and intensity of shock focusing. The pressure and vorticity contours indicate that the jet formation should be attributed to the pressure pulsation caused by shock focusing, and the jet development is ascribed to the vorticity induction. Finally, a time ratio proposed in the previous work for determining the shock-focusing type is verified by experiments.

  14. Performance, emission, and combustion characteristics of twin-cylinder common rail diesel engine fuelled with butanol-diesel blends.

    Science.gov (United States)

    Lamani, Venkatesh Tavareppa; Yadav, Ajay Kumar; Gottekere, Kumar Narayanappa

    2017-10-01

    Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~ 4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NO x ), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NO x , and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel.

  15. An investigation of the fluid-structure interaction of piston/cylinder interface

    Science.gov (United States)

    Pelosi, Matteo

    The piston/cylinder lubricating interface represents one of the most critical design elements of axial piston machines. Being a pure hydrodynamic bearing, the piston/cylinder interface fulfills simultaneously a bearing and sealing function under oscillating load conditions. Operating in an elastohydrodynamic lubrication regime, it also represents one of the main sources of power loss due to viscous friction and leakage flow. An accurate prediction of the time changing tribological interface characteristics in terms of fluid film thickness, dynamic pressure field, load carrying ability and energy dissipation is necessary to create more efficient interface designs. The aim of this work is to deepen the understanding of the main physical phenomena defining the piston/cylinder fluid film and to discover the impact of surface elastic deformations and heat transfer on the interface behavior. For this purpose, a unique fully coupled multi-body dynamics model has been developed to capture the complex fluid-structure interaction phenomena affecting the non-isothermal fluid film conditions. The model considers the squeeze film effect due to the piston micro-motion and the change in fluid film thickness due to the solid boundaries elastic deformations caused by the fluid film pressure and by the thermal strain. The model has been verified comparing the numerical results with measurements taken on special designed test pumps. The fluid film calculated dynamic pressure and temperature fields have been compared. Further validation has been accomplished comparing piston/cylinder axial viscous friction forces with measured data. The model has been used to study the piston/cylinder interface behavior of an existing axial piston unit operating at high load conditions. Numerical results are presented in this thesis.

  16. High temperature piezoresistive {beta}-SiC-on-SOI pressure sensor for combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. von; Ziermann, R.; Reichert, W.; Obermeier, E. [Tech. Univ. Berlin (Germany). Microsensor and Actuator Technol. Center; Eickhoff, M.; Kroetz, G. [Daimler Benz AG, Munich (Germany); Thoma, U.; Boltshauser, T.; Cavalloni, C. [Kistler Instrumente AG, Winterthur (Switzerland); Nendza, J.P. [TRW Deutschland GmbH, Barsinghausen (Germany)

    1998-08-01

    For measuring the cylinder pressure in combustion engines of automobiles a high temperature pressure sensor has been developed. The sensor is made of a membrane based piezoresistive {beta}-SiC-on-SOI (SiCOI) sensor chip and a specially designed housing. The SiCOI sensor was characterized under static pressures of up to 200 bar in the temperature range between room temperature and 300 C. The sensitivity of the sensor at room temperature is approximately 0.19 mV/bar and decreases to about 0.12 mV/bar at 300 C. For monitoring the dynamic cylinder pressure the sensor was placed into the combustion chamber of a gasoline engine. The measurements were performed at 1500 rpm under different loads, and for comparison a quartz pressure transducer from Kistler AG was used as a reference. The maximum pressure at partial load operation amounts to about 15 bar. The difference between the calibrated SiCOI sensor and the reference sensor is significantly less than 1 bar during the whole operation. (orig.) 8 refs.

  17. Image analysis of moving seeds in an indented cylinder

    DEFF Research Database (Denmark)

    Buus, Ole; Jørgensen, Johannes Ravn

    2010-01-01

    inspection in seed cleaning equipment. A prototype of an indented cylinder will be constructed. To make it more dynamic, the cylinder itself will be manufactured using 3D printing technology. The input will come either from 3D scans of existing cylinders or by defining their topology using parametric B...

  18. Investigation of breached depleted UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    DeVan, J.H. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1991-12-31

    In June 1990, during a three-site inspection of cylinders being used for long-term storage of solid depleted UF{sub 6}, two 14-ton cylinders at Portsmouth, Ohio, were discovered with holes in the barrel section of the cylinders. An investigation team was immediately formed to determine the cause of the failures and their impact on future storage procedures and to recommend corrective actions. Subsequent investigation showed that the failures most probably resulted from mechanical damage that occurred at the time that the cylinders had been placed in the storage yard. In both cylinders evidence pointed to the impact of a lifting lug of an adjacent cylinder near the front stiffening ring, where deflection of the cylinder could occur only by tearing the cylinder. The impacts appear to have punctured the cylinders and thereby set up corrosion processes that greatly extended the openings in the wall and obliterated the original crack. Fortunately, the reaction products formed by this process were relatively protective and prevented any large-scale loss of uranium. The main factors that precipitated the failures were inadequate spacing between cylinders and deviations in the orientations of lifting lugs from their intended horizontal position. After reviewing the causes and effects of the failures, the team`s principal recommendation for remedial action concerned improved cylinder handling and inspection procedures. Design modifications and supplementary mechanical tests were also recommended to improve the cylinder containment integrity during the stacking operation.

  19. 46 CFR 58.30-30 - Fluid power cylinders.

    Science.gov (United States)

    2010-10-01

    ... all pneumatic power transmission systems. (b) Fluid power cylinders consisting of a container and a... 46 Shipping 2 2010-10-01 2010-10-01 false Fluid power cylinders. 58.30-30 Section 58.30-30... MACHINERY AND RELATED SYSTEMS Fluid Power and Control Systems § 58.30-30 Fluid power cylinders. (a) The...

  20. Imperfection effects on the buckling of hydrostatically loaded cylinders

    DEFF Research Database (Denmark)

    Pinna, Rodney; Madsen, Søren

    2015-01-01

    imperfection sensitivity. Work on cylinders with other loading conditions, such as hydrostatic loading, is more limited. Similarly, there is limited work on cylinders with boundary conditions other than simply-supported ends. This paper looks at the case of cylinders under hydrostatic load, which is often...

  1. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  2. Sub-wavelength metamaterial cylinders with multiple dipole resonances

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM...... configuration thus offer the possibility for multi-resonant electrically small configurations....

  3. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  4. Optimal control of lift/drag ratios on a rotating cylinder

    Science.gov (United States)

    Ou, Yuh-Roung; Burns, John A.

    1992-01-01

    We present the numerical solution to a problem of maximizing the lift to drag ratio by rotating a circular cylinder in a two-dimensional viscous incompressible flow. This problem is viewed as a test case for the newly developing theoretical and computational methods for control of fluid dynamic systems. We show that the time averaged lift to drag ratio for a fixed finite-time interval achieves its maximum value at an optimal rotation rate that depends on the time interval.

  5. Interfering with the wake of cylinder by flexible filaments

    Science.gov (United States)

    Pinelli, Alfredo; Omidyeganeh, Mohammad

    2015-11-01

    This work is the very first attempt to understand and optimize the configuration of flexible filaments placed on the lee side of a bluff body to manipulate flow transitions and bifurcations. It is found that the presence of a sparse set of flexible filaments on the lee side of a cylinder can interfere with the 2D-3D transition process resulting in elongation of recirculation bubble, inhibition of higher order unstable modes, and narrowing the global energy content about a particular shedding frequency. Filaments become effective when spacing between them is smaller than the dominant unstable mode at each particular Reynolds number, i.e. A and B modes. In another study, by a particular arrangement the reconfigured filaments can reduce pressure fluctuations in the wake and drop lift flluctuations significantly (~= 80 %).

  6. Fiber-Optic Pressure Sensor With Dynamic Demodulation Developed

    Science.gov (United States)

    Lekki, John D.

    2002-01-01

    Researchers at the NASA Glenn Research Center developed in-house a method to detect pressure fluctuations using a fiber-optic sensor and dynamic signal processing. This work was in support of the Intelligent Systems Controls and Operations project under NASA's Information Technology Base Research Program. We constructed an optical pressure sensor by attaching a fiber-optic Bragg grating to a flexible membrane and then adhering the membrane to one end of a small cylinder. The other end of the cylinder was left open and exposed to pressure variations from a pulsed air jet. These pressure variations flexed the membrane, inducing a strain in the fiber-optic grating. This strain was read out optically with a dynamic spectrometer to record changes in the wavelength of light reflected from the grating. The dynamic spectrometer was built in-house to detect very small wavelength shifts induced by the pressure fluctuations. The spectrometer is an unbalanced interferometer specifically designed for maximum sensitivity to wavelength shifts. An optimum pathlength difference, which was determined empirically, resulted in a 14-percent sensitivity improvement over theoretically predicted path-length differences. This difference is suspected to be from uncertainty about the spectral power difference of the signal reflected from the Bragg grating. The figure shows the output of the dynamic spectrometer as the sensor was exposed to a nominally 2-kPa peak-to-peak square-wave pressure fluctuation. Good tracking, sensitivity, and signal-to-noise ratios are evident even though the sensor was constructed as a proof-of-concept and was not optimized in any way. Therefore the fiber-optic Bragg grating, which is normally considered a good candidate as a strain or temperature sensor, also has been shown to be a good candidate for a dynamic pressure sensor.

  7. Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine.

    Science.gov (United States)

    Aleiferis, Pavlos; Charalambides, Alexandros; Hardalupas, Yannis; Soulopoulos, Nikolaos; Taylor, A M K P; Urata, Yunichi

    2015-05-10

    Schlieren [Schlieren and Shadowgraphy Techniques (McGraw-Hill, 2001); Optics of Flames (Butterworths, 1963)] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole-field temperature distributions. The objective of the current work was to design a schlieren system to measure line-of-sight (LOS)-averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of internal combustion (IC) engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3% for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the LOS measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air

  8. Ultimate capacity and influenced factors analysis of nuclear RC containment subjected to internal pressure

    International Nuclear Information System (INIS)

    Song Chenning; Hou Gangling; Zhou Guoliang

    2014-01-01

    Ultimate compressive bearing capacity, influenced factors and its rules of nuclear RC containment are key problems of safety assessment, accident treatment and structure design, etc. Ultimate compressive bearing capacity of nuclear RC containment is shown by concrete damaged plasticity model and steel double liner model of ABAQUS. The study shows that the concrete of nuclear RC containment cylinder wall becomes plastic when the internal pressure is up to 0.87 MPa, the maximum tensile strain of steel liner exceeds 3000 × 10 6 and nuclear RC containment reaches ultimate status when the internal pressure is up to 1.02 MPa. The result shows that nuclear RC containment is in elastic condition under the design internal pressure and the bearing capacity meets requirement. Prestress and steel liner play key parts in the ultimate internal pressure and failure mode of nuclear RC containment. The study results have value for the analysis of ultimate compressive bearing capacity, structure design and safety assessment. (authors)

  9. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  10. Experimental seismic test of fluid coupled co-axial cylinders

    International Nuclear Information System (INIS)

    Chu, M.L.; Brown, S.J.; Lestingi, J.F.

    1979-01-01

    The dynamic response of fluid coupled coaxial cylindrical shells is of interest to the nuclear industry with respect to the seismic design of the reactor vessel and thermal liner. The experiments described present a series of tests which investigate the effect of the annular clearance between the cylinders (gap) on natural frequency, damping, and seismic response of both the inner and outer cylinders. The seismic input is a time history base load to the flexible fluid filled coaxial cylinders. The outer cylinder is elastically supported at both ends while the inner cylinder is supported only at the base (lower) end

  11. SU-F-18C-11: Diameter Dependency of the Radial Dose Distribution in a Long Polyethylene Cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Bakalyar, D; McKenney, S [Henry Ford Health System, Detroit, MI (United States); Feng, W [New York Presbyterian Hospital, Tenafly, NJ (United States)

    2014-06-15

    Purpose: The radial dose distribution in the central plane of a long cylinder following a long CT scan depends upon the diameter and composition of the cylinder. An understanding of this behavior is required for determining the spatial average of the dose in the central plane. Polyethylene, the material for construction of the TG200/ICRU phantom (30 cm in diameter) was used for this study. Size effects are germane to the principles incorporated in size specific dose estimates (SSDE); thus diameter dependency was explored as well. Method: ssuming a uniform cylinder and cylindrically symmetric conditions of irradiation, the dose distribution can be described using a radial function. This function must be an even function of the radial distance due to the conditions of symmetry. Two effects are accounted for: The direct beam makes its weakest contribution at the center while the contribution due to scatter is strongest at the center and drops off abruptly at the outer radius. An analytic function incorporating these features was fit to Monte Carlo results determined for infinite polyethylene cylinders of various diameters. A further feature of this function is that it is integrable. Results: Symmetry and continuity dictate a local extremum at the center which is a minimum for the larger sizes. The competing effects described above can Resultin an absolute maximum occurring between the center and outer edge of the cylinders. For the smallest cylinders, the maximum dose may occur at the center. Conclusion: An integrable, analytic function can be used to characterize the radial dependency of dose for cylindrical CT phantoms of various sizes. One use for this is to help determine average dose distribution over the central cylinder plane when equilibrium dose has been reached.

  12. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Lauderbach, Lisa [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Garza, Raul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Ferranti, Louis [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Vitello, Peter [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. Finally, the total detonation energy density was locked to the v = 7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  13. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark; Lauderbach, Lisa; Garza, Raul; Ferranti, Louis; Vitello, Peter

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. The total detonation energy density was locked to the v=7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  14. The last glacial maximum

    Science.gov (United States)

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  15. Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

    Science.gov (United States)

    Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

    2018-04-01

    To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

  16. Transient thermal stresses in composite hollow circular cylinder due to partial heat generation

    International Nuclear Information System (INIS)

    Goshima, Takahito; Miyao, Kaju

    1979-01-01

    Clad materials are adopted for the machines and structures used in contact with high temperature, corrosive atmosphere in view of their strength and economy. Large thermal stress sometimes arises in clad cylinders due to uneaven temperature field and the difference in linear thermal expansion. Vessels are often heated uneavenly, and shearing stress occurs, which is not observed in uniform heating. In this study, infinitely long, concentric cylinders of two layers were analyzed, when the internal heat changing in stepped state is generated in cylindrical form. The unsteady thermal stress occurred was determined, using thermo-elastic potential and stress functions, and assuming the thermal properties and elastic modulus of materials as constant regardless of the temperature. Laplace transformation was used, and the basic equations for thermo-elastic displacement were employed as the basis of calculation. The analysis of the temperature distribution and stress is explained. Numerical calculation was carried out on the example of an internal cylinder of SUS 304 stainless steel and an external cylinder of mild steel. The maximum shearing stress occurred in the direction of 40 deg from the heat source, and was affected largely by the position of heat generation. The effect became remarkable as time elapsed. (Kako, I.)

  17. Experimental study of natural convection heat transfer from an isothermal combined geometry (downward cone- cylinder)

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, A. [Yazd Univ., Yazd (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Goharkhah, M.; Ashjaee, M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Mechanical Engineering

    2009-07-01

    Laminar free convection heat transfer from an isothermal combined geometry which consists of a downward cone attached to a vertical cylinder was studied. In particular, a Mach-Zehnder interferometer was used to determine the change in local and average heat transfer coefficients on the surface of an isothermal combined geometry for different vertex angles. The effect of the vertex angle on heat transfer was also investigated by keeping the height of the cylinder and slant length of the cone constant for all objects. The experimental data showed that the local heat transfer coefficient on the conical part increased in the vicinity of the cylinder and cone intersection. The distance between the point of minimum heat transfer coefficient on the cone and vertex of the cone decreased as the vertex angle increased. The maximum average Nusselt number for a constant Rayleigh number was obtained for the geometry with the smallest vertex angle. For all objects, the average Nusselt number increased with an increase in the Rayleigh number. An experiment was carried out on a vertical isothermal cylinder of circular cross section in order to validate the experimental approach. An analytical solution was found to be in good agreement with experimental results. 31 refs., 9 figs.

  18. Experimental study on an IC engine in-cylinder flow using different steady-state flow benches

    Directory of Open Access Journals (Sweden)

    M. El-Adawy

    2017-12-01

    Full Text Available In-cylinder air flow structures are known to strongly impact on the performance and combustion of internal combustion engines (ICE. Therefore the aim of this paper is to experimentally study an IC engine in-cylinder flow under steady-state conditions. Different methods can be used to characterize the in-cylinder flow which are optical engines and laser diagnostics, computational fluid dynamic and steady-state flow bench. Here we are concentrating on two different types of flow benches. The first (Ricardo uses the impulse torque meter method while the other (FEV uses the paddle wheel technique. The experiments were carried out on the same cylinder head and the same pressure difference across the inlet valves of 600 mmH2O in order to compare the results. The experimental results are presented in terms of the measured air flow rate, flow coefficient, discharge coefficient and non-dimensional rig tumble. Moreover, number of modifications were conducted on the FEV flow bench in order to apply particle image velocimetry measurements on the vertical tumble plane, which passing through the middle of the cylinder at different valve lifts. The results show that a reasonably good level of agreement can be achieved between both methods, providing the methods of calculations of the various parameters are consistent. Keywords: In-cylinder flow, Flow bench, Tumble motion, Flow coefficient, Particle image velocimetry

  19. Progress with the NESC spinning cylinder project and other NESC projects

    International Nuclear Information System (INIS)

    Wintle, J.B.; Hurst, R.C.; Hemsworth, B.

    1995-01-01

    The first international project (NESC I) of the Network of Evaluating Steel Components is a spinning cylinder, pressurized thermal shock (PTS) experiment. The main objective of the project is to validate the non-destructive evaluation and structural mechanics procedures for PWR reactor pressure vessels under PTS conditions. Contributing organizations world-wide will participate in this blind trial which embraces all aspects of structural integrity assessment. This paper describes the progress of the project to date, covering cylinder manufacture and inspection, materials evaluation, structural analysis and test instrumentation. It emphasizes the importance of networking global expertise in a managed framework and of the partnership, co-operation and teamwork developed by the contributing organizations through the five Task Groups constituting the NESC I. Finally, five new initiatives for projects managed by the Network are currently under review and described in this paper

  20. Progress with the NESC spinning cylinder project and other NESC projects

    International Nuclear Information System (INIS)

    Wintle, J.B.; Hurst, R.C.; Hemsworth, B.

    1995-01-01

    The first international project (NESC I) of the Network for Evaluating Steel Components is a spinning cylinder, pressurized thermal shock (PTS) experiment. The main objective of the project is to validate the non-destructive evaluation and structural mechanics procedures for PWR reactor pressure vessels under PTS conditions. Contributing organizations world-wide will participate in this blind trial which embraces all aspects of structural integrity assessment. This paper describes the progress of the project to date, covering cylinder manufacture and inspection, materials evaluation, structural analysis and test instrumentation. It emphasises the importance of networking global expertise in a managed framework and of the partnership, co-operation and teamwork developed by the contributing organizations through the five Task Groups constituting NESC I. Finally, five new initiatives for projects managed by the Network are currently under review and described in this paper. (author). 2 refs, 6 figs

  1. A multidomain chebyshev pseudo-spectral method for fluid flow and heat transfer from square cylinders

    KAUST Repository

    Wang, Zhiheng

    2015-01-01

    A simple multidomain Chebyshev pseudo-spectral method is developed for two-dimensional fluid flow and heat transfer over square cylinders. The incompressible Navier-Stokes equations with primitive variables are discretized in several subdomains of the computational domain. The velocities and pressure are discretized with the same order of Chebyshev polynomials, i.e., the PN-PN method. The Projection method is applied in coupling the pressure with the velocity. The present method is first validated by benchmark problems of natural convection in a square cavity. Then the method based on multidomains is applied to simulate fluid flow and heat transfer from square cylinders. The numerical results agree well with the existing results. © Taylor & Francis Group, LLC.

  2. Modeling for Friction of Four Stroke Four Cylinder In-Line Petrol Engine

    Directory of Open Access Journals (Sweden)

    P.C. Mishra

    2013-09-01

    Full Text Available A four stroke four cylinder in-line petrol engine is modeled to estimate various performance parameters. The solution is based on tribology and dynamics principle. The detailed parameters relating to engine friction and lubrication are computed numerically for the engine firing order 1-3-4-2. The numerical method is based on finite difference method that solves coupled Reynolds Equation and Energy Equation. Output includes the movie thickness, friction force, friction power loss and temperature rise in the ring liner conjunction in all four cylinders. Transient regime of ring liner lubrication isaddressed while the same changes from hydrodynamic to mixed in an engine cycle. Momentary cessation near the top and bottom dead center that causes boundary interaction is analyzed through asperity contact. The non - Newtonian behavior of lubricant film due to pressure and temperature is addresses using viscosity -pressure- temperature inter relationship.

  3. The effect of valve strategy on in-cylinder flow and combustion

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, F

    1997-01-01

    This paper examines the effects of different valve strategies and their effect on in-cylinder flow and combustion. A conventional four valve per cylinder otto engine was modified to enable optical access. The flow measurements were made with a two-component laser Doppler velocimetry system. The combustion was monitored by running pressure data from a pressure transducer through a one-zone heat release model. The results show that when the valves operate normally a barrel flow is present and when one valve is closed a swirling flow occurs. No increase in turbulence was found with later phasing, except in the case of very late inlet valve opening and port deactivation. This resulted in a jet with high turbulence, making the combustion fast and stable, even with a very lean mixture ({lambda}=1.8). 6 refs, 44 figs, 4 tabs

  4. Development of Hybrid Type Flexible Pneumatic Cylinder for Considering Less Air Consumption

    Directory of Open Access Journals (Sweden)

    Tamaki Hiroaki

    2016-01-01

    Full Text Available Inexpensive rehabilitation devices that can be used at home are required because of a lack of PT and welfare workers. In the previous study, the low-cost portable rehabilitation device using a flexible spherical actuator that consists of flexible pneumatic cylinder was proposed and tested. However, a compact and high power compressor that supplies air pressure to pneumatic actuator has not been developed yet. In particular, the heat generated by compressing air prevents to miniaturize it. To realize a home rehabilitation, the small-sized compressors or less air consuming flexible actuators are required. In this study, a hybrid type flexible pneumatic cylinder driven by electric motors and air pressure is proposed and tested. The concept, the construction and the operating principle of the proposed actuator were described. The position control using the tested actuator is also carried out.

  5. Control of a 420 KN Discrete Displacement Cylinder Drive for the Wavestar Wave Energy Converter

    DEFF Research Database (Denmark)

    Hansen, Rico H.; Andersen, Torben Ole; Pedersen, Henrik C.

    2014-01-01

    absorbers. The system is implemented using multi-chambered cylinders, where the different chambers may be switched between three pressure lines using a manifold with fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC) is obtained, where force control is implemented by shifting between...... different area/pressure combinations. Currently, a 420 kN DDC prototype has been implemented and tested at the newly commissioned full size wave energy testbench at Aalborg University. The initial design and control of the DDC had poorly damped switching transients. These issues treated in this paper....... This leads to a new control, which gives a smooth operating DDC, while meeting the requirements to the efficiency of the drive....

  6. Influence of the stacking sequence of layers on the mechanical behavior of polymeric composite cylinders; Influencia da configuracao de bobinagem no comportamento mecanico de cilindros de composito polimerico

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Osni de

    2006-07-01

    This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction. (author)

  7. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

  8. Hydrostatic Paradox: Experimental Verification of Pressure Equilibrium

    Science.gov (United States)

    Kodejška, C.; Ganci, S.; Ríha, J.; Sedlácková, H.

    2017-01-01

    This work is focused on the experimental verification of the balance between the atmospheric pressure acting on the sheet of paper, which encloses the cylinder completely or partially filled with water from below, where the hydrostatic pressure of the water column acts against the atmospheric pressure. First of all this paper solves a theoretical…

  9. Probable maximum flood control

    International Nuclear Information System (INIS)

    DeGabriele, C.E.; Wu, C.L.

    1991-11-01

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility

  10. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1988-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. We review the need for such methods in data analysis and show, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. We conclude with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  11. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  12. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1989-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. The author reviews the need for such methods in data analysis and shows, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. He concludes with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  13. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    MAF outperforms the functional PCA in concentrating the interesting' spectra/shape variation in one end of the eigenvalue spectrum and allows for easier interpretation of effects. Conclusions. Functional MAF analysis is a useful methods for extracting low dimensional models of temporally or spatially......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in......\\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  14. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  15. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  16. Energy Loss, Velocity Distribution, and Temperature Distribution for a Baffled Cylinder Model

    Science.gov (United States)

    Brevoort, Maurice J

    1937-01-01

    A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that cooling can be improved by 20 percent by using a correctly designed baffle. Such a gain is as effective as a 65 percent increase in pressure drop across the standard baffle, which had a 1/4 inch clearance between baffle and fin tips.

  17. Optimal Control as a method for Diesel engine efficiency assessment including pressure and NO_x constraints

    International Nuclear Information System (INIS)

    Guardiola, Carlos; Climent, Héctor; Pla, Benjamín; Reig, Alberto

    2017-01-01

    Highlights: • Optimal Control is applied for heat release shaping in internal combustion engines. • Optimal Control allows to assess the engine performance with a realistic reference. • The proposed method gives a target heat release law to define control strategies. - Abstract: The present paper studies the optimal heat release law in a Diesel engine to maximise the indicated efficiency subject to different constraints, namely: maximum cylinder pressure, maximum cylinder pressure derivative, and NO_x emission restrictions. With this objective, a simple but also representative model of the combustion process has been implemented. The model consists of a 0D energy balance model aimed to provide the pressure and temperature evolutions in the high pressure loop of the engine thermodynamic cycle from the gas conditions at the intake valve closing and the heat release law. The gas pressure and temperature evolutions allow to compute the engine efficiency and NO_x emissions. The comparison between model and experimental results shows that despite the model simplicity, it is able to reproduce the engine efficiency and NO_x emissions. After the model identification and validation, the optimal control problem is posed and solved by means of Dynamic Programming (DP). Also, if only pressure constraints are considered, the paper proposes a solution that reduces the computation cost of the DP strategy in two orders of magnitude for the case being analysed. The solution provides a target heat release law to define injection strategies but also a more realistic maximum efficiency boundary than the ideal thermodynamic cycles usually employed to estimate the maximum engine efficiency.

  18. Effect of the Presence of Semi-circular Cylinders on Heat Transfer From Heat Sources Placed in Two Dimensional Channel

    Directory of Open Access Journals (Sweden)

    Ahmed W. Mustava

    2013-04-01

    Full Text Available The effect of a semi-circular cylinders in a two dimensional channel on heat transfer by forced convection from two heat sources with a constant temperature has been studied numerically. Each channel contains two heat sources; one on the upper surface of the channel and the other on the lower surface of the channel. There is semi-circular cylinder under the source in upper surface and there is semi-circular cylinder above the source in lower surface. The location of the second heat source with its semi-cylinder has been changed and keeps the first source with its semi- cylinder at the same location. The flow and temperature field are studied numerically with different values of Reynolds numbers and for different spacing between the centers of the semi-cylinders. The laminar flow field is analyzed numerically by solving the steady forms of the two-dimensional incompressible Navier- Stokes and energy equations.  The Cartesian velocity components and pressure on a collocated (non-staggered grid are used as dependent variables in the momentum equations, which discretized by finite volume method, body fitted coordinates are used to represent the complex channel geometry accurately, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass.  The range of Reynolds number is (Re= 100 – 800 and the range of the spacing between the semi-cylinders is(1-4 and the Prandtl number is 0.7.The results showed that increasing the spacing between the semi-cylinders increases the average of Nusselt number of the first heat source for all Reynolds numbers. As well as the results show that the best case among the cases studied to enhance the heat transfer is when the second heat source and its semi-cylinder located on at the distance (S=1.5 from the first half of the cylinder and the Reynolds number is greater than (Re ≥ 400 because of the

  19. Engineering model for low-velocity impacts of multi-material cylinder on a rigid boundary

    Directory of Open Access Journals (Sweden)

    Delvare F.

    2012-08-01

    Full Text Available Modern ballistic problems involve the impact of multi-material projectiles. In order to model the impact phenomenon, different levels of analysis can be developed: empirical, engineering and simulation models. Engineering models are important because they allow the understanding of the physical phenomenon of the impact materials. However, some simplifications can be assumed to reduce the number of variables. For example, some engineering models have been developed to approximate the behavior of single cylinders when impacts a rigid surface. However, the cylinder deformation depends of its instantaneous velocity. At this work, an analytical model is proposed for modeling the behavior of a unique cylinder composed of two different metals cylinders over a rigid surface. Material models are assumed as rigid-perfectly plastic. Differential equation systems are solved using a numerical Runge-Kutta method. Results are compared with computational simulations using AUTODYN 2D hydrocode. It was found a good agreement between engineering model and simulation results. Model is limited by the impact velocity which is transition at the interface point given by the hydro dynamical pressure proposed by Tate.

  20. Exhaust gas heat recovery through secondary expansion cylinder and water injection in an internal combustion engine

    Directory of Open Access Journals (Sweden)

    Nassiri Toosi Ali

    2017-01-01

    Full Text Available To enhance thermal efficiency and increase performance of an internal combustion engine, a novel concept of coupling a conventional engine with a secondary 4-stroke cylinder and direct water injection process is proposed. The burned gases after working in a traditional 4-stroke combustion cylinder are transferred to a secondary cylinder and expanded even more. After re-compression of the exhaust gases, pre-heated water is injected at top dead center. The evaporation of injected water not only recovers heat from exhaust gases, but also increases the mass of working gas inside the cylinder, therefore improves the overall thermal efficiency. A 0-D/1-D model is used to numerically simulate the idea. The simulations outputs showed that the bottoming cycle will be more efficient at higher engines speeds, specifically in a supercharged/turbocharged engine, which have higher exhaust gas pressure that can reproduce more positive work. In the modeled supercharged engine, results showed that brake thermal efficiency can be improved by about 17%, and brake power by about 17.4%.

  1. Interaction of a weak shock wave with a discontinuous heavy-gas cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiansheng; Yang, Dangguo; Wu, Junqiang [High Speed Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000 (China); Luo, Xisheng, E-mail: xluo@ustc.edu.cn [Advanced Propulsion Laboratory, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026 (China)

    2015-06-15

    The interaction between a cylindrical inhomogeneity and a weak planar shock wave is investigated experimentally and numerically, and special attention is given to the wave patterns and vortex dynamics in this scenario. A soap-film technique is realized to generate a well-controlled discontinuous cylinder (SF{sub 6} surrounded by air) with no supports or wires in the shock-tube experiment. The symmetric evolving interfaces and few disturbance waves are observed in a high-speed schlieren photography. Numerical simulations are also carried out for a detailed analysis. The refracted shock wave inside the cylinder is perturbed by the diffracted shock waves and divided into three branches. When these shock branches collide, the shock focusing occurs. A nonlinear model is then proposed to elucidate effects of the wave patterns on the evolution of the cylinder. A distinct vortex pair is gradually developing during the shock-cylinder interaction. The numerical results show that a low pressure region appears at the vortex core. Subsequently, the ambient fluid is entrained into the vortices which are expanding at the same time. Based on the relation between the vortex motion and the circulation, several theoretical models of circulation in the literature are then checked by the experimental and numerical results. Most of these theoretical circulation models provide a reasonably good prediction of the vortex motion in the present configuration.

  2. Aerodynamic loading on a cylinder behind an airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.J.; Huang, L.; Zhou, Y. [Hong Kong Polytechnic University, Department of Mechanical Engineering, Kowloon (Hong Kong)

    2005-05-01

    The interaction between the wake of a rotor blade and a downstream cylinder holds the key to the understanding and control of electronic cooling fan noise. In this paper, the aerodynamic characteristics of a circular cylinder are experimentally studied in the presence of an upstream NACA 4412 airfoil for the cylinder-diameter-based Reynolds numbers of Re{sub d}=2,100-20,000, and the airfoil chord-length-based Reynolds numbers of Re{sub c}=14,700-140,000. Lift and drag fluctuations on the cylinder, and the longitudinal velocity fluctuations of the flow behind the cylinder were measured simultaneously using a load cell and two hot wires, respectively. Data analysis shows that unsteady forces on the cylinder increase significantly in the presence of the airfoil wake. The dependence of the forces on two parameters is investigated, that is, the lateral distance (T) between the airfoil and the cylinder, and the Reynolds number. The forces decline quickly as Tincreases. For Re{sub c}<60,000, the vortices shed from the upstream airfoil make a major contribution to the unsteady forces on the cylinder compared to the vortex shedding from the cylinder itself. For Re{sub c}>60,000, no vortices are generated from the airfoil, and the fluctuating forces on the cylinder are caused by its own vortex shedding. (orig.)

  3. 75 FR 30292 - Airworthiness Directives; AVOX Systems and B/E Aerospace Oxygen Cylinders as Installed on Various...

    Science.gov (United States)

    2010-06-01

    ... by the reported rupture of a high-pressure gaseous oxygen cylinder, which had insufficient strength... supply for the flightcrew, and injury to cabin occupants or other support personnel. DATES: This AD... incorporation by reference of certain publications listed in this AD. ADDRESSES: For service information...

  4. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  5. Thin circular cylinder under axisymmetrical thermal and mechanical loading

    International Nuclear Information System (INIS)

    Arnaudeau, F.; Zarka, J.; Gerij, J.

    1977-01-01

    To assess structural integrity of components subjected to cyclic thermal loadings one must look at thermal ratchetting as a possible failure mode. Considering a thin circular cylinder subjected to constant internal pressure and cyclically varying thermal gradient through the thickness Bree, J. Strain Analysis 2 (1967) No.3, obtained a diagram that serves as a foundation for many design rules (e.g.: ASME code). The upper part of the french LMFBR main vessel is subjected to an axisymmetrical axial thermal loading and an axial load (own weight). Operation of the reactor leads to cyclic variations of the axial thermal loading. The question that arises is whether or not the Bree diagram is realistic for such loading conditions. A special purpose computer code (Ratch) was developed to analyse a thin circular cylinder subjected to axisymmetrical mechanical and thermal loadings. The Mendelson's approach of this problem is followed. Classical Kirchoff-Love hypothesis of thin shells is used and a state of plane stress is assumed. Space integrations are performed by Gaussian quadrature in the axial direction and by Simpson's one third rule throughout the thickness. Thermoelastic-plastic constitutive equations are solved with an implicit scheme (Nguyen). Thermovisco-plastic constitutive equations are solved with an explicit time integration scheme (Treanor's algorithm especially fitted). A Bree type diagram is obtained for an axial step of temperature which varies cyclically and a sustained constant axial load. The material behavior is assumed perfectly plastic and creep effect is not considered. Results show that the domain where no ratchetting occurs is reduced when compared with the domain predicted by the Bree diagram

  6. Prestressed concrete reactor vessel thermal cylinder model study

    International Nuclear Information System (INIS)

    Callahan, J.P.; Canonico, D.A.; Richardson, M.; Corum, J.M.; Dodge, W.G.; Robinson, G.C.; Whitman, G.D.

    1977-01-01

    The thermal cylinder experiment was designed both to provide information for evaluating the capability of analytical methods to predict the time-dependent stress-strain behavior of a 1 / 6 -scale model of the barrel section of a single-cavity prestressed concrete reactor vessel and to demonstrate the structural behavior under design and off-design thermal conditions. The model was a thick-walled cylinder having a height of 1.22 m, a thickness of 0.46 m, and an outer diameter of 2.06 m. It was prestressed both axially and circumferentially and subjected to 4.83 MPa internal pressure together with a thermal crossfall imposed by heating the inner surface to 338.8 K and cooling the outer surface to 297.1 K. The initial 460 days of testing were divided into time periods that simulated prestressing, heatup, reactor operation, and shutdown. At the conclusion of the simulated operating period, the model was repressurized and subjected to localized heating at 505.4 K for 84 days to produce an off-design hot-spot condition. Comparisons of experimental data with calculated values obtained using the SAFE-CRACK finite-element computer program showed that the program was capable of predicting time-dependent behavior in a vessel subjected to normal operating conditions, but that it was unable to accurately predict the behavior during off-design hot-spot heating. Readings made using a neutron and gamma-ray backscattering moisture probe showed little, if any, migration of moisture in the concrete cross section. Destructive examination indicated that the model maintained its basic structural integrity during localized hot-spot heating

  7. Thermodynamic analysis of an in-cylinder waste heat recovery system for internal combustion engines

    International Nuclear Information System (INIS)

    Zhu, Sipeng; Deng, Kangyao; Qu, Shuan

    2014-01-01

    In this paper, an in-cylinder waste heat recovery system especially for turbocharged engines is proposed to improve the thermal efficiencies of internal combustion engines. Simplified recovery processes can be described as follows: superheated steam generated by engine waste heat is injected into the pipe before the turbine to increase the boost pressure of the fresh air; intake valve close timing is adjusted to control the amount of fresh air as the original level, and thus the higher pressure charged air expands in the intake stroke and transfers the pressure energy directly to the crankshaft. In this way, the increased turbine output by the pre-turbine steam injection is finally recovered in the cylinder, which is different from the traditional Rankine cycle. The whole energy transfer processes are studied with thermodynamic analyses and numerical simulations. The results show that the mass flow rate of the injected steam has the biggest influence on the energy transfer processes followed by the temperature of the injected steam. With this in-cylinder waste heat recovery system, the fuel economy of a selected turbocharged diesel engine can be improved by 3.2% at the rated operating point when the injected mass flow ratio is set to be 0.1. - Highlights: • An in-cylinder waste heat recovery system is proposed. • Effects of injected parameters are studied with energy and exergy balance theories. • Variations of operating points on the compressor map are studied in detail. • The fuel economy is improved by 3.2% at the rated operating point

  8. Large-scale thermal-shock experiments with clad and unclad steel cylinders

    International Nuclear Information System (INIS)

    Cheverton, R.D.

    1992-01-01

    Flaw behavior trends associated with pressurized-thermal-shock (PTS) loading of pressurized-water-reactor pressure vessels have been under investigation at the Oak Ridge National Laboratory for nearly 20 years. During that time, twelve thermal-shock experiments with thick-walled (152 mm) steel cylinders were conducted as a part of the investigations. The first eight experiments were conducted with unclad cylinders initially containing shallow (8--19 mm) two-dimensional and semicircular inner-surface flaws. These experiments demonstrated, in good agreement with linear elastic fracture mechanics, crack initiation and arrest, a series of initiation/arrest events with deep penetration of the wall, long crack jumps, arrest with the stress intensity factor (K I ) increasing with crack depth, extensive surface extension of an initially short and shallow (semicircular) flaw, and warm prestressing with K I ≤ 0. The remaining four experiments were conducted with clad cylinders containing initially shallow (19--24 mm) semielliptical subclad and surface flaws at the inner surface. In the first of these experiments one of six equally spaced (60 degrees) open-quotes identicalclose quotes subclad flaws extended nearly the length of the cylinder (1,220 mm) beneath the cladding (no crack extension into the cladding) and nearly 50% of the wall, radially. For the final experiment, four of the semielliptical subclad flaws that had not propagated previously were converted to surface flaws, and they experienced extensive extension beneath the cladding with no cracking of the cladding. Information from this series of thermal-shock experiments is being used in the evaluation of the PTS issue

  9. Predicition of the first spinning cylinder test using continuum damage mechanics

    International Nuclear Information System (INIS)

    Lidbury, D.P.G.; Sherry, A.H.; Bilby, B.A.; Howard, I.C.; Li, Z.H.; Eripret, C.

    1993-01-01

    For many years large-scale experiments have been performed world-wide to validate aspects of fracture mechanics methodology. Special emphasis has been given to correlations between small- and large-scale specimen behaviour in quantifying the structural behaviour of pressure vessels, piping and closures. Within this context, the first three Spinning Cylinder Tests, performed by AEA Technology at its Risley Laboratory, addressed the phenomenon of stable crack growth by ductile tearing in contained yield and conditions simulating pressurized thermal shock loading in a PWR reactor pressure vessel. A notable feature of the test data was that the effective resistance to crack growth, as measured in terms of the J R-curve, was appreciably greater than that anticipated from small-scale testing, both at initiation and after small amounts (a few millimeters) of tearing. In the present paper, two independent finite element analyses of the First Spinning Cylinder Test (SC 1) are presented and compared. Both involved application of the Rousselier ductile damage theory in an attempt to better understand the transferability of test data from small specimens to structural validation tests. In each instance, the parameters associated with the theory's constitutive equation were calibrated in terms of data from notched-tensile and (or) fracture mechanics tests, metallographic observation and (or) chemical composition. The evolution of ductile damage local to the crack tip during SC 1 was thereby calculated and, together with a crack growth criterion based on the maximization of opening-mode stress, used as the basis for predicting cylinder R-Curves (angular velocity vs. Δa, J-integral vs. Δa). The results show the Rousselier model to be capable of correctly predicting the enhancement of tearing toughness of the cylinder relative to that of conventional test specimens, given an appropriate choice of finite element cell size in the region representing the crack tip

  10. Cylinder management: how to reduce investments

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-10-15

    De-regulated and not mature markets are often pledged with illegal cross-filling, unlawful use and misuse of cylinders despite branding and property rights. These points were among the topics discussed at the round table on 'good business practices' organised during the 16. World LP Gas Forum, last October in Santiago. Didier Gilles, head of Totalgaz International Department, explained how the marketer is dealing with this kind of problems to protect its assets. Didier Gilles gave an example of this policy in Morocco. We publish large excerpts of this paper. (author)

  11. Flow around an oscillating cylinder: computational issues

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Fengjian; Gallardo, José P; Pettersen, Bjørnar [Department of Marine Technology, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Andersson, Helge I, E-mail: fengjian.jiang@ntnu.no [Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2017-10-15

    We consider different computational issues related to the three-dimensionalities of the flow around an oscillating circular cylinder. The full time-dependent Navier–Stokes equations are directly solved in a moving reference frame by introducing a forcing term. The choice of quantitative validation criteria is discussed and discrepancies of previously published results are addressed. The development of Honji vortices shows that short simulation times may lead to incorrect quasi-stable vortex patterns. The viscous decay of already established Honji vortices is also examined. (paper)

  12. Cylindrical vortex wake model: right cylinder

    DEFF Research Database (Denmark)

    Branlard, Emmanuel; Gaunaa, Mac

    2015-01-01

    The vortex system consisting of a bound vortex disk, a root vortex and a vortex cylinder as introduced by Joukowski in 1912 is further studied in this paper. This system can be used for simple modeling of rotors (e.g. wind turbines) with infinite number of blades and finite tip-speed ratios....... For each vortex element, the velocity components in all directions and in the entire domain are computed analytically in a novel approach. In particular, the velocity field from the vortex actuator disk is derived for the first time. The induction from the entire vortex system is studied and is seen...

  13. Vortex structure behind highly heated two cylinders in parallel arrangements

    International Nuclear Information System (INIS)

    Kurita, Eiichirou; Yahagi, Yuji

    2008-01-01

    Vortex structures behind twin, highly heated cylinders in parallel arrangements have been investigated experimentally. The experiments were conducted under the following conditions: cylinder diameter, D=4 mm; mean flow velocity, U ∞ =1.0 m/s; Reynolds number, Re=250; cylinder clearance, S/D=0.5 - 1.4; and cylinder heat flux, q=0 - 72.6 kW/m 2 . For S/D > 1.2, the Karman vortex street is formed alternately behind each cylinder divided on the slit flow. The slit flow velocity increases with a decrease in S/D and decreases with increasing heat flux. For S/D 2 ). As a result, the increased local kinematic viscosity and S/D play a key role for the vortex structure and formation behind arrangements of two parallel cylinders. (author)

  14. Controlling chaos in a fluid flow past a movable cylinder

    International Nuclear Information System (INIS)

    Vallejo, Juan C.; Marino, Ines P.; Sanjuan, Miguel A.F.; Kurths, Juergen

    2003-01-01

    The model of a two-dimensional fluid flow past a cylinder is a relatively simple problem with a strong impact in many applied fields, such as aerodynamics or chemical sciences, although most of the involved physical mechanisms are not yet well known. This paper analyzes the fluid flow past a cylinder in a laminar regime with Reynolds number, Re, around 200, where two vortices appear behind the cylinder, by using an appropriate time-dependent stream function and applying non-linear dynamics techniques. The goal of the paper is to analyze under which circumstances the chaoticity in the wake of the cylinder might be modified, or even suppressed. And this has been achieved with the help of some indicators of the complexity of the trajectories for the cases of a rotating cylinder and an oscillating cylinder

  15. Effect of Surface Coatings on Cylinders Exposed to Underwater Shock

    Directory of Open Access Journals (Sweden)

    Y.W. Kwon

    1994-01-01

    Full Text Available The response of a coated cylinder (metallic cylinder coated with a rubber material subjected to an underwater explosion is analyzed numerically. The dynamic response of the coated cylinder appears to be adversely affected when impacted by an underwater shock wave under certain conditions of geometry and material properties of the coating. When adversely affected, significant deviations in values of axial stress, hoop stress, and strain are observed. The coated cylinder exhibits a larger deformation and higher internal energy in the metallic material. Rubber coatings appeared to inhibit energy dissipation from the metallic material to the surrounding water medium. A parametric study of various coatings was performed on both aluminum and steel cylinders. The adverse effect of the coating decreased when the stiffness of the rubber layer increased, indicating the existence of a threshold value. The results of this study indicate that the stiffness of the coating is a critical factor to the shock hardening of the coated cylinder.

  16. Reducing Fatigue Loading Due to Pressure Shift in Discrete Fluid Power Force Systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    power force system. The current paper investigates the correlation between pressure oscillations in the cylinder chambers and valve flow in the manifold. Furthermore, the correlation between the pressure shifting time and the pressure overshoot is investigated. The study therefore focus on how to shape......Discrete Fluid Power Force Systems is one of the topologies gaining focus in the pursuit of lowering energy losses in fluid power transmission systems. The cylinder based Fluid Power Force System considered in this article is constructed with a multi-chamber cylinder, a number of constant pressure...... oscillations in the cylinder chamber, especially for systems with long connections between the cylinder and the valve manifold. Hose pressure oscillations will induce oscillations in the produced piston force. Hence, pressure oscillations may increase the fatigue loading on systems employing a discrete fluid...

  17. Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    International Nuclear Information System (INIS)

    1996-07-01

    The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact

  18. Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact.

  19. Electromagnetic forces on type-II superconducting rotating cylinders

    International Nuclear Information System (INIS)

    Saif, A.G.; Refai, T.F.; El-Sabagh, M.A.

    1995-01-01

    Analytical solutions of the electromagnetic fields are presented for a system composed of an infinitely long superconducting cylinder rotating about its axis and placed parallel to two infinitely long normal conducting wires. Both wires carry the same alternating current. From the obtained electromagnetic fields the electromagnetic power loss on the cylinder surface, electromagnetic forces due to induced currents, electromagnetic torque, and the work opposing the rotation of the cylinder are calculated. (orig.)

  20. PIV Measurements of He II Counterflow Around a Cylinder

    International Nuclear Information System (INIS)

    Fuzier, S.; Van Stiver, S. W.; Zhang, T.

    2006-01-01

    The induced flow field of counterflow He II across a circular cylinder has been quantitatively studied using the particle image velocimetry (PIV) technique. Two different size cylinders (6.35 mm and 2 mm in diameter) were used and placed in a 20 mm wide rectangular channel. In these experiments, large-scale eddy motion generated by the He II counterflow was observed both in front of and behind the cylinder, an effect which has no analogue in classical fluids

  1. Characteristics of Sulfuric Acid Condensation on Cylinder Liners of Large Two-Stroke Marine Engines

    DEFF Research Database (Denmark)

    Cordtz, Rasmus Lage; Mayer, Stefan; Schramm, Jesper

    . Formation of corrosive sulfuric acid in the cylinder gas is modeled with a cali-brated engine model that incorporates a detailed sulfur reaction mechanism. Condensation of sulfuric acid follows the analogy between heat and mass transfer. Average bulk gas acid dew points are calculated by applying two......-phase thermochemistry of the binary H2O-H2SO4 system. Max dew points of typically more than 200 °C are modeled close to max pressure and variations in terms of operating conditions are not large. However small increments of the dew point provided by e.g. the residual gas fraction, operating pressure, sulfur content...

  2. Ambulatory blood pressure parameters after canrenone addition to existing treatment regimens with maximum tolerated dose of angiotensin-converting enzyme inhibitors/angiotensin II type 1 receptor blockers plus hydrochlorothiazide in uncontrolled hypertensive patients

    Directory of Open Access Journals (Sweden)

    Guasti L

    2017-08-01

    Full Text Available Luigina Guasti,1,* Giovanni Gaudio,2,* Alessandro Lupi,3 Marinella D’Avino,4 Carla Sala,5,6 Amedeo Mugellini,7 Vito Vulpis,8 Salvatore Felis,9 Riccardo Sarzani,10,11 Massimo Vanasia,12 Pamela Maffioli,7 Giuseppe Derosa7 1Research Center on Dyslipidemia, Internal Medicine 1, University of Insubria, Varese, Italy; 2Internal Medicine Division, Ospedale Angelo Bellini, ASST Valle Olona Somma, Varese, Italy; 3Cardiology Unit, ASL VCO Verbania-Domodossola, Verbania, Italy; 4Unit for the Treatment of Arterial Hypertension, Ospedale Cardarelli, Napoli, Italy; 5Department of Clinical Sciences and Community Health, University of Milan, Milano, Italy; 6Cardiovascular Unit, Fondazione IRCCSS Policlinico, Milano, Italy; 7Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy; 8Unit for the Diagnosis and Treatment of Arterial Hypertension, Department of Internal Medicine, Policlinico di Bari, Bari, Italy; 9Cardiology Unit, Ospedale Garibaldi, Catania, Italy; 10ESH Center of Hypertension, Internal Medicine and Geriatrics, University Politecnica delle Marche, Ancona, Italy; 11IRCCS-INRCA, Ancona, Italy; 12THERABEL GiEnne Pharma, Milano, Italy *These authors contributed equally to this work Background: Blockade of the renin–angiotensin–aldosterone system is a cornerstone in cardiovascular disease prevention and hypertension treatment. The relevance of ambulatory blood pressure monitoring (ABPM has been widely confirmed for both increasing the accuracy of blood pressure (BP measurements, particularly in pharmacological trials, and focusing on 24 h BP prognostic parameters. The aim of this study was to assess the effects of canrenone addition on ambulatory BP in uncontrolled hypertensive patients already treated with the highest tolerated dose of angiotensin-converting enzyme (ACE inhibitors or angiotensin II type 1 receptor (AT1R antagonists plus hydrochlorothiazide (HCT. Methods: ABPM was performed at baseline and after 3

  3. Stress and reliability analyses of multilayered composite cylinder under thermal and mechanical loads

    Science.gov (United States)

    Wang, Xiaohua

    The coupling resulting from the mutual influence of material thermal and mechanical parameters is examined in the thermal stress analysis of a multilayered isotropic composite cylinder subjected to sudden axisymmetric external and internal temperature. The method of complex frequency response functions together with the Fourier transform technique is utilized. Because the coupling parameters for some composite materials, such as carbon-carbon, are very small, the effect of coupling is neglected in the orthotropic thermal stress analysis. The stress distributions in multilayered orthotropic cylinders subjected to sudden axisymmetric temperature loading combined with dynamic pressure as well as asymmetric temperature loading are also obtained. The method of Fourier series together with the Laplace transform is utilized in solving the heat conduction equation and thermal stress analysis. For brittle materials, like carbon-carbon composites, the strength variability is represented by two or three parameter Weibull distributions. The 'weakest link' principle which takes into account both the carbon-carbon composite cylinders. The complex frequency response analysis is performed on a multilayered orthotropic cylinder under asymmetrical thermal load. Both deterministic and random thermal stress and reliability analyses can be based on the results of this frequency response analysis. The stress and displacement distributions and reliability of rocket motors under static or dynamic line loads are analyzed by an elasticity approach. Rocket motors are modeled as long hollow multilayered cylinders with an air core, a thick isotropic propellant inner layer and a thin orthotropic kevlar-epoxy case. The case is treated as a single orthotropic layer or a ten layered orthotropic structure. Five material properties and the load are treated as random variable with normal distributions when the reliability of the rocket motor is analyzed by the first-order, second-moment method (FOSM).

  4. Instantaneous flow field above the free end of finite-height cylinders and prisms

    International Nuclear Information System (INIS)

    Rostamy, N.; Sumner, D.; Bergstrom, D.J.; Bugg, J.D.

    2013-01-01

    Highlights: • PIV measurements of the flow above the free end of finite-height bodies. • Effect of cross-sectional shape of the models on the instantaneous flow. • Small-scale structures generated by the separated shear layer were revealed. • Effect of aspect ratio on the reattachment of the separated flow on the free end. -- Abstract: The flow above the free ends of surface-mounted finite-height circular cylinders and square prisms was studied experimentally using particle image velocimetry (PIV). Cylinders and prisms with aspect ratios of AR = 9, 7, 5, and 3 were tested at a Reynolds number of Re = 4.2 × 10 4 . The bodies were mounted normal to a ground plane and were partially immersed in a turbulent zero-pressure-gradient boundary layer, where the boundary layer thickness relative to the body width was δ/D = 1.6. PIV measurements were made above the free ends of the bodies in a vertical plane aligned with the flow centreline. The present PIV results provide insight into the effects of aspect ratio and body shape on the instantaneous flow field. The recirculation zone under the separated shear layer is larger for the square prism of AR = 3 compared to the more slender prism of AR = 9. Also, for a square prism with low aspect ratio (AR = 3), the influence of the reverse flow over the free end surface becomes more significant compared to that for a higher aspect ratio (AR = 9). For the circular cylinder, a cross-stream vortex forms within the recirculation zone. As the aspect ratio of the cylinder decreases, the reattachment point of the separated flow on the free end surface moves closer to the trailing edge. For both the square prism and circular cylinder cases, the instantaneous velocity vector field and associated in-plane vorticity field revealed small-scale structures mostly generated by the separated shear layer

  5. Enrichment Assay Methods Development for the Integrated Cylinder Verification System

    International Nuclear Information System (INIS)

    Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.; Curtis, Michael M.

    2009-01-01

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility's entire product-cylinder inventory. Pacific Northwest National Laboratory (PNNL) is developing a concept to automate the verification of enrichment plant cylinders to enable 100 percent product-cylinder verification and potentially, mass-balance calculations on the facility as a whole (by also measuring feed and tails cylinders). The Integrated Cylinder Verification System (ICVS) could be located at key measurement points to positively identify each cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until IAEA inspector arrival. The three main objectives of this FY09 project are summarized here and described in more detail in the report: (1) Develop a preliminary design for a prototype NDA system, (2) Refine PNNL's MCNP models of the NDA system, and (3) Procure and test key pulse-processing components. Progress against these tasks to date, and next steps, are discussed.

  6. Enrichment Assay Methods Development for the Integrated Cylinder Verification System

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.; Curtis, Michael M.

    2009-10-22

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility's entire product-cylinder inventory. Pacific Northwest National Laboratory (PNNL) is developing a concept to automate the verification of enrichment plant cylinders to enable 100 percent product-cylinder verification and potentially, mass-balance calculations on the facility as a whole (by also measuring feed and tails cylinders). The Integrated Cylinder Verification System (ICVS) could be located at key measurement points to positively identify each cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until IAEA inspector arrival. The three main objectives of this FY09 project are summarized here and described in more detail in the report: (1) Develop a preliminary design for a prototype NDA system, (2) Refine PNNL's MCNP models of the NDA system, and (3) Procure and test key pulse-processing components. Progress against these tasks to date, and next steps, are discussed.

  7. Inflation of polymer melts into elliptic and circular cylinders

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Christensen, Jens Horslund; Gøttsche, Søren

    2000-01-01

    A thin sheet (membrane) of the polymeric material is clamped between a Teflon-coated thermostated plate and a thermostated aluminium cylinder. By applying thermostated air through the plate, the polymer membrane deforms into an elliptic or a circular cylinder. The position of the top of the infla......A thin sheet (membrane) of the polymeric material is clamped between a Teflon-coated thermostated plate and a thermostated aluminium cylinder. By applying thermostated air through the plate, the polymer membrane deforms into an elliptic or a circular cylinder. The position of the top...

  8. Self-accelerating parabolic cylinder waves in 1-D

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C., E-mail: cyuce@anadolu.edu.tr

    2016-11-25

    Highlights: • We find a new class of self-accelerating waves. • We show that parabolic cylinder waves self-accelerates in a parabolic potential. • We discuss that truncated parabolic cylinder waves propagates large distance without almost being non-diffracted in free space. - Abstract: We introduce a new self-accelerating wave packet solution of the Schrodinger equation in one dimension. We obtain an exact analytical parabolic cylinder wave for the inverted harmonic potential. We show that truncated parabolic cylinder waves exhibits their accelerating feature.

  9. An experiments and characteristics analysis of the sealless cylinder

    International Nuclear Information System (INIS)

    Kim, Young Cheol; Kim, Dong Soo; Bae, Sang Kyu; Kim, Sung Jong

    2004-01-01

    This paper shows a performance analysis for conical type sealless cylinders and rod bearings. The pistons without seal have partly cylindrical and conical shapes. 2 dimensional Reynolds equation and FD(Finite Differential) numerical techniques are utilized for the performance analysis. The relationship among self-centering forces and leakage flows are investigated. Also, optimal design values for a sealless cylinder are presented. A prototype of sealless cylinder which had rod bearing with four pockets, five pockets, and six pockets was manufactured respectively. Leakage flow test is conducted to evaluate performance of piston and rod bearing in sealless cylinder

  10. Flow past two tandem square cylinders vibrating transversely in phase

    International Nuclear Information System (INIS)

    Mithun, M G; Tiwari, Shaligram

    2014-01-01

    Numerical investigations have been carried out to study the wake characteristics of flow past two tandem square cylinders vibrating in phase. Both the cylinders vibrate in a transverse direction, i.e., perpendicular to the incoming flow with the same frequency and amplitude. The frequency of vibration of the cylinders and the inter-cylinder spacing are varied for fixed values of the Reynolds number (Re = 100) and the amplitude ratio (A/D = 0.4). The synchronous or lock-in regime for the oscillatory wake of the vibrating cylinders has been identified by varying the frequency of the vibration from f e  = 0.4 f 0 to 1.6 f 0 (f 0 being the frequency of vortex shedding behind a stationary square cylinder). The characteristics of lift and drag and the mechanism of vortex shedding are studied by varying the excitation frequency within the lock-in range for each value of inter-cylinder spacing. The complex interaction of flow between the cylinders gives rise to a variety of characteristically different shedding patterns in their wake. For values of inter-cylinder spacing equal to 2D and 3D, periodic, as well as quasi-periodic, lock-in behaviors are observed in the synchronous range. (paper)

  11. Spark ignition engine control: estimation and prediction of the in-cylinder mass and chemical species; Controle moteur a allumage commande: estimation / prediction de la masse et de la composition du melange enferme dans le cylindre

    Energy Technology Data Exchange (ETDEWEB)

    Giansetti, P.

    2005-09-15

    Spark ignition engine control has become a major issue regarding compliance with emissions legislation while ensuring driving comfort. The objective of this thesis was to estimate the mass and composition of gases inside the cylinder of an engine based on physics in order to insure better control of transient phases taking into account residual gases as well as exhaust gas recirculation. Residual gas fraction has been characterized using two experiments and one CFD code. A model has been validated experimentally and integrated into an observer which predicts pressure and temperature inside the manifold. The predictions of the different gas flows and the chemical species inside the cylinder are deduced. A closed loop observer has been validated experimentally and in simulation. Moreover, an algorithm estimating the fresh and burned gas mass from the cylinder pressure has been proposed in order to obtain the information cycle by cycle and cylinder by cylinder. (author)

  12. Effects of Elevated Temperatures on the Compressive Strength Capacity of Concrete Cylinders Confined with FRP Sheets: An Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Sherif El-Gamal

    2015-01-01

    Full Text Available Due to their high strength, corrosion resistance, and durability, fiber reinforced polymers (FRP are very attractive for civil engineering applications. One of these applications is the strengthening of concrete columns with FRP sheets. The performance of this strengthening technique at elevated temperature is still questionable and needs more investigations. This research investigates the effects of exposure to high temperatures on the compressive strength of concrete cylinders wrapped with glass and carbon FRP sheets. Test specimens consisted of 30 unwrapped and 60 wrapped concrete cylinders. All specimens were exposed to temperatures of 100, 200, and 300°C for periods of 1, 2, and 3 hours. The compressive strengths of the unwrapped concrete cylinders were compared with their counterparts of the wrapped cylinders. For the unwrapped cylinders, test results showed that the elevated temperatures considered in this study had almost no effect on their compressive strength; however, the wrapped specimens were significantly affected, especially those wrapped with GFRP sheets. The compressive strength of the wrapped specimens decreased as the exposure period and the temperature level increased. After three hours of exposure to 300°C, a maximum compressive strength loss of about 25.3% and 37.9%, respectively, was recorded in the wrapped CFRP and GFRP specimens.

  13. The capillary interaction between two vertical cylinders

    KAUST Repository

    Cooray, Himantha

    2012-06-27

    Particles floating at the surface of a liquid generally deform the liquid surface. Minimizing the energetic cost of these deformations results in an inter-particle force which is usually attractive and causes floating particles to aggregate and form surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite difference method. Inter-particle force-separation curves for pairs of vertical cylinders are then calculated for different radii and contact angles. These results are compared with previously published asymptotic and experimental results. For large inter-particle separations and conditions such that the meniscus slope remains small everywhere, good agreement is found between all three approaches (numerical, asymptotic and experimental). This is as expected since the asymptotic results were derived using the linearized Laplace-Young equation. For steeper menisci and smaller inter-particle separations, however, the numerical simulation resolves discrepancies between existing asymptotic and experimental results, demonstrating that this discrepancy was due to the nonlinearity of the Laplace-Young equation. © 2012 IOP Publishing Ltd.

  14. Terminal project heat convection in thin cylinders

    International Nuclear Information System (INIS)

    Morales Corona, J.

    1992-01-01

    Heat convection in thin cylinders and analysis about natural convection for straight vertical plates, and straight vertical cylinders submersed in a fluid are presented some works carry out by different authors in the field of heat transfer. In the part of conduction, deduction of the equation of heat conduction in cylindrical coordinates by means of energy balance in a control volume is presented. Enthalpy and internal energy are used for the outlining of the equation and finally the equation in its vectorial form is obtained. In the convection part development to calculate the Nusselt number for a straight vertical plate by a forces analysis, an energy balance and mass conservation over a control volume is outlined. Several empiric correlations to calculate the Nusselt number and its relations with other dimensionless numbers are presented. In the experimental part the way in which a prototype rode is assembled is presented measurements of temperatures attained in steady state and in free convection for working fluids as air and water are showed in tables. Also graphs of Nusselt numbers obtained in the experimental way through some empiric correlations are showed (Author)

  15. Relation of maximum blood pressure during exercise and regular physical activity in normotensive men with left ventricular mass and hypertrophy. MARATHOM Investigators. Medida de la Actividad fisica y su Relación Ambiental con Todos los Lípidos en el HOMbre.

    Science.gov (United States)

    Molina, L; Elosua, R; Marrugat, J; Pons, S

    1999-10-15

    The relation between maximum systolic blood pressure (BP) during exercise and left ventricular (LV) mass is controversial. Physical activity also induces LV mass increase. The objective was to assess the relation between BP response to exercise and LV mass in normotensive men, taking into account physical activity practice. A cross-sectional study was performed. Three hundred eighteen healthy normotensive men, aged between 20 and 60 years, participated in this study. The Minnesota questionnaire was used to assess physical activity practice. An echocardiogram and a maximum exercise test were performed. LV mass was calculated and indexed to body surface area. LV hypertrophy was defined as a ventricular mass index > or =134 g/m2. BP was measured at the moment of maximum effort. Hypertensive response was considered when BP was > or =210 mm Hg. In the multiple linear regression model, maximum systolic BP was associated with LV mass index and correlation coefficient was 0.27 (SE 0.07). Physical activity practice and age were also associated with LV mass. An association between hypertensive response to exercise and LV hypertrophy was observed (odds ratio 3.16). Thus, BP response to exercise is associated with LV mass and men with systolic BP response > or =210 mm Hg present a 3-times higher risk of LV hypertrophy than those not reaching this limit. Physical activity practice is related to LV mass, but not to LV hypertrophy.

  16. Effect of Cylinder Liner Oil Grooves Shape on Two-Stroke Marine Diesel Engine's Piston Ring Friction Force

    Directory of Open Access Journals (Sweden)

    Salaheldin A. Mohamad

    2015-02-01

    Full Text Available The dimensions, area densities, and geometry of macroscale surface textures may affect the performance of hydrodynamic lubrication interface. Reported in this paper are the investigations of the effect of surface textures bottom shapes on the friction forces between piston ring and cylinder liner for two-stroke marine diesel engine, using numerically generated textures and average Reynolds equation. These textures are on the cylinder liner surface in the form of circumferential oil grooves with different aspect ratios and different area densities. The hydrodynamic pressure distribution is also calculated using Reynolds boundary condition. The results revealed that the bottom shape could positively affect the friction between moving surfaces, as it could provide a microwedge or microstep bearing that tends to enhance the lubrication condition between piston ring and cylinder liner.

  17. Stirling engine with pressurized crankcase

    Science.gov (United States)

    Corey, John A.

    1988-01-01

    A two piston Stirling engine wherein the pistons are coupled to a common crankshaft via bearing means, the pistons include pad means to minimize friction between the pistons and the cylinders during reciprocation of the pistons, means for pressurizing the engine crankcase, and means for cooling the crankshaft and the bearing means eliminating the need for oil in the crankcase.

  18. Analysis of historical and recent PBX 9404 cylinder tests using FLAG

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, Hasani Omar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Whitley, Von Howard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-31

    Cylinder test experiments using aged PBX-9404 were recently conducted. When compared to similar historical tests using the same materials, but different diagnostics, the data indicate that PBX 9404 imparts less energy to surrounding copper. The purpose of this work was to simulate historical and recent cylinder tests using the Lagrangian hydrodynamics code, FLAG, and identify any differences in the energetic behavior of the material. Nine experiments spanning approximately 4.5 decades were simulated, and radial wall expansions and velocities were compared. Equation-of-state parameters were adjusted to obtain reasonable matches with experimental data. Pressure-volume isentropes were integrated, and resultant energies at specific volume expansions were compared. FLAG simulations matched to experimental data indicate energetic changes of approximately -0.57% to -0.78% per decade.

  19. Three-dimensional transition in the wake of a circular cylinder by direct numerical simulation

    International Nuclear Information System (INIS)

    Kang, S. J.; Mo, J. O.; Lee, Y. H.; Tanahashi, M.; Miyauchi, T.

    2001-01-01

    Three-dimensional time-dependent flow past a circular cylinder is numerically investigated using direct numerical simulation for Reynolds number 280 and 300. The higher-order finite difference scheme is employed for the spatial distributions along with the second order Adams-Bashforth and the first order backward-Euler time integration. In x-y plane, the convection term is applied by the 5th order upwind scheme and the pressure and viscosity terms are applied by the 4th order central difference. And in spanwise, Navier-Stokes equation is distributed using of spectral method. At Reynolds number 259 the two-dimensional wake becomes linearly unstable to a second branch of modes with wavelength about 1.0 diameters at onset (B-mode). Present results of three-dimensional effects of in wake of a circular cylinder is represented with spanwise and streamwise vorticity contours as Reynolds numbers

  20. Exact solution for stresses/displacements in a multilayered hollow cylinder under thermo-mechanical loading

    International Nuclear Information System (INIS)

    Yeo, W.H.; Purbolaksono, J.; Aliabadi, M.H.; Ramesh, S.; Liew, H.L.

    2017-01-01

    In this study, a new analytical solution by the recursive method for evaluating stresses/displacements in multilayered hollow cylinder under thermo-mechanical loading was developed. The results for temperature distribution, displacements and stresses obtained by using the proposed solution were shown to be in good agreement with the FEM results. The proposed analytical solution was also found to produce more accurate results than those by the analytical solution reported in literature. - Highlights: • A new analytical solution for evaluating stresses in multilayered hollow cylinder under thermo-mechanical loading. • A simple computational procedure using a recursive method. • A promising technique for evaluating the operating axial and hoop stresses in pressurized composite vessels.

  1. A Space Cam Mechanism for Power Transmission of an Opposite-cylinder Piston Engine

    Directory of Open Access Journals (Sweden)

    Zhang Haoyue

    2015-01-01

    Full Text Available For the purpose of improving the engine’s power density, we put forward a new type of power transmission mechanism which is used for opposed-cylinder engine. The gas pressure acts on the cam through the piston and push rod, and the spindle rotation of external is driven by the cam. The design of spatial cam work surface is completed by using the enveloping theory of a family of space curves, the force between roller and cam is analyzed using dynamic analysis software. Under the condition of equal number, size and stroke of piston, the new one with larger power density is more compact in structure than the traditional power transmission mechanism, and the reaction force on either side of the main shaft and the acting force between pistons and cylinders are smaller than those in traditional one, which prolongs the service life of the pistons.

  2. Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

    International Nuclear Information System (INIS)

    Supe, Sanjay S.; Bijina, T.K.; Varatharaj, C.; Shwetha, B.; Arunkumar, T.; Sathiyan, S.; Ganesh, K.M.; Ravikumar, M.

    2009-01-01

    Endometrial carcinoma is the most common malignancy arising in the female genital tract. Intracavitary vaginal cuff irradiation may be given alone or with external beam irradiation in patients determined to be at risk for locoregional recurrence. Vaginal cylinders are often used to deliver a brachytherapy dose to the vaginal apex and upper vagina or the entire vaginal surface in the management of postoperative endometrial cancer or cervical cancer. The dose distributions of HDR vaginal cylinders must be evaluated carefully, so that clinical experiences with LDR techniques can be used in guiding optimal use of HDR techniques. The aim of this study was to optimize dose distribution for Gammamed plus vaginal cylinders. Placement of dose optimization points was evaluated for its effect on optimized dose distributions. Two different dose optimization point models were used in this study, namely non-apex (dose optimization points only on periphery of cylinder) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6-cm active length. Thus 13 optimization points were available at the periphery of the cylinder. The coordinates of the points along the curvature depended on the cylinder diameters and were chosen for each cylinder so that four points were distributed evenly in the curvature portion of the cylinder. Diameter of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0-cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. All optimizations in this study were carried for dose of 6 Gy at dose optimization points. For both non-apex and apex models of vaginal cylinders, doses for apex point and three dome

  3. Visualization by discharge illumination technique and modification by plasma actuator of rarefied Mach 2 airflow around a cylinder

    International Nuclear Information System (INIS)

    Leger, L; Depussay, E; Sellam, M; Barbosa, E

    2013-01-01

    The use of plasma actuators for flow control has received considerable attention in recent years. This kind of device seems to be an appropriate means of raising abilities in flow control thanks to total electric control, no moving parts and a fast response time. The experimental work presented here shows, firstly, the non-intrusive character of the visualization of the density field of an airflow around a cylinder obtained using a plasma luminescence technique. Experiments are made in a continuous supersonic wind tunnel. The static pressure in the flow is 8 Pa, the mean free path is about 0.3 mm and the airflow velocity is 510 m s −1 . Pressure measurements obtained by means of glass Pitot tube without the visualization discharge are proposed. Measured and simulated pressure profiles are in good agreement in the region near the cylinder. There is good correlation between numerical simulations of the supersonic flow field, analytical model predictions and experimental flow visualizations obtained by a plasma luminescence technique. Consequently, we show that the plasma luminescence technique is non-intrusive. Secondly, the effect of a dc discharge on a supersonic rarefied air flow around a cylinder is studied. An electrode is flush mounted on the cylinder. Stagnation pressure profiles are examined for different electrode positions on the cylinder. A shock wave modification depending on the electrode location is observed. The discharge placed at the upstream stagnation point induces an upstream shift of the bow shock, whereas a modification of the shock wave shape is observed when it is placed at 45° or 90°. (paper)

  4. Torsional vibrations of infinite composite poroelastic cylinders | Shah ...

    African Journals Online (AJOL)

    ... radius of composite poroelastic solid cylinder to the radius of the inner solid cylinder. Results of previous works are shown as special case of the present analysis. By ignoring liquid effects, the results of purely elastic solid are obtained. International Journal of Engineering, Science and Technology, Vol. 2, No. 6, 2010, pp.

  5. Mobile Robot Localization by Remote Viewing of a Colored Cylinder

    Science.gov (United States)

    Volpe, R.; Litwin, T.; Matthies, L.

    1995-01-01

    A system was developed for the Mars Pathfinder rover in which the rover checks its position by viewing the angle back to a colored cylinder with different colors for different angles. The rover determines distance by the apparent size of the cylinder.

  6. NGSI: Function Requirements for a Cylinder Tracking System

    International Nuclear Information System (INIS)

    Branney, S.

    2012-01-01

    While nuclear suppliers currently track uranium hexafluoride (UF 6 ) cylinders in various ways, for their own purposes, industry practices vary significantly. The NNSA Office of Nonproliferation and International Security's Next Generation Safeguards Initiative (NGSI) has begun a 5-year program to investigate the concept of a global monitoring scheme that uniquely identifies and tracks UF 6 cylinders. As part of this effort, NGSI's multi-laboratory team has documented the 'life of a UF 6 cylinder' and reviewed IAEA practices related to UF 6 cylinders. Based on this foundation, this paper examines the functional requirements of a system that would uniquely identify and track UF 6 cylinders. There are many considerations for establishing a potential tracking system. Some of these factors include the environmental conditions a cylinder may be expected to be exposed to, where cylinders may be particularly vulnerable to diversion, how such a system may be integrated into the existing flow of commerce, how proprietary data generated in the process may be protected, what a system may require in terms of the existing standard for UF 6 cylinder manufacture or modifications to it and what the limiting technology factors may be. It is desirable that a tracking system should provide benefit to industry while imposing as few additional constraints as possible and still meeting IAEA safeguards objectives. This paper includes recommendations for this system and the analysis that generated them.

  7. Faraday effect in hollow quantum cylinder of finite thickness

    International Nuclear Information System (INIS)

    Ismailov, T.G.; Jabrailova, G.G.

    2009-01-01

    The interband Faraday rotation in hollow quantum cylinder of finite thickness is theoretically investigated. Faraday rotation in the dependence on incident light energy for different values of cylinder thickness. It is seen that the resonance peaks appear on Faraday rotation curve. The roles of selection are obtained

  8. Wave propagation in coated cylinders with reference to fretting fatigue

    Indian Academy of Sciences (India)

    is to study stress wave propagation in cylinders with reference to high frequency fretting. ... The motivation for studying of fretting fatigue at higher frequency is to investigate the ... Hence focus in this work is given to thin rods and cylinders. The.

  9. An analytical study of the effects of transverse shear deformation and anisotropy on buckling loads of laminated cylinders. M.S. Thesis - George Washington Univ.

    Science.gov (United States)

    Jegley, Dawn C.

    1987-01-01

    Buckling loads of thick-walled orthotropic and anisotropic simply supported circular cylinders are predicted using a higher-order transverse-shear deformation theory. A comparison of buckling loads predicted by the conventional first-order transverse-shear deformation theory and the higher-order theory show that the additional allowance for transverse shear deformation has a negligible effect on the predicted buckling loads of medium-thick metallic isotropic cylinders. However, the higher-order theory predicts buckling loads which are significantly lower than those predicted by the first-order transverse-shear deformation theory for certain short, thick-walled cylinders which have low through-the-thickness shear moduli. A parametric study of the effects of ply orientation on the buckling load of axially compressed cylinders indicates that laminates containing 45 degree plies are most sensitive to transverse-shear deformation effects. Interaction curves for buckling loads of cylinders subjected to axial compressive and external pressure loadings indicate that buckling loads due to external pressure loadings are as sensitive to transverse-shear deformation effects as buckling loads due to axial compressive loadings. The effects of anisotropy are important over a much wider range of cylinder geometries than the effects of transverse shear deformation.

  10. Fluxmetric and magnetometric demagnetizing factors for cylinders

    International Nuclear Information System (INIS)

    Chen, D.-X.; Pardo, E.; Sanchez, A.

    2006-01-01

    Fluxmetric and magnetometric demagnetizing factors, N f and N m , for cylinders along the axial direction are numerically calculated as functions of material susceptibility χ and the ratio γ of length to diameter. The results have an accuracy better than 0.1% with respect to min(N f,m ,1-N f,m ) and are tabulated in the range of 0.01= m along the radial direction is evaluated with a lower accuracy from N m along the axis and tabulated in the range of 0.01=<γ=<1 and -1=<χ<∼. Some previous results are discussed and several applications are explained based on the new results

  11. Switchable and Tunable Aerodynamic Drag on Cylinders

    Science.gov (United States)

    Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  12. Kinetic stability analyses in a bumpy cylinder

    International Nuclear Information System (INIS)

    Dominguez, R.R.; Berk, H.L.

    1981-01-01

    Recent interest in the ELMO Bumpy Torus (EBT) has prompted a number of stability analyses of both the hot electron rings and the toroidal plasma. Typically these works employ the local approximation, neglecting radial eigenmode structure and ballooning effects to perform the stability analysis. In the present work we develop a fully kinetic formalism for performing nonlocal stability analyses in a bumpy cylinder. We show that the Vlasov-Maxwell integral equations (with one ignorable coordinate) are self-adjoint and hence amenable to analysis using numerical techniques developed for self-adjoint systems of equations. The representation we obtain for the kernel of the Vlasov-Maxwell equations is a differential operator of arbitrarily high order. This form leads to a manifestly self-adjoint system of differential equations for long wavelength modes

  13. Electrogravitational stability of oscillating streaming fluid cylinder

    International Nuclear Information System (INIS)

    Hasan, Alfaisal A.

    2011-01-01

    The electrogravitational instability of on oscillating streaming fluid cylinder under the action of the selfgravitating, capillary and electrodynamic forces has been discussed. The model is governed by the Mathieu second order integro-differential equation. Some limiting cases are recovering from the present general one. The capillary force is destabilizing in a small axisymmetric domain 0< x<1 and stabilizing otherwise. In the absence of electric fields, we found that the model is unstable in a small domain while it is selfgravitating stable in all other domains. The presence of the electric field led to the presence of a great number of stable waves. The electric field has a strong stabilizing influence on the selfgravitating instability of the model. The capillary force has a strong destabilizing influence on the selfgravitating instability of the model. Generally, the uniform stream supports the unstable waves, while the oscillating streaming has stability tendency.

  14. Inductance position sensor for pneumatic cylinder

    Directory of Open Access Journals (Sweden)

    Pavel Ripka

    2018-04-01

    Full Text Available The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the inductance is increasing with inserting rod due to the rod permeability. This mode has disadvantage of slow response to piston movement and also high temperature sensitivity. At the frequency of 45 Hz the inductance is position independent, as the permeability effect is compensated by the eddy current effect. At higher frequencies eddy current effects in the rod prevail, the inductance is decreasing with inserting rod. In this mode the sensitivity is smaller but the sensor response is fast and temperature stability is better. We show that FEM simulation of this sensor using measured material properties gives accurate results, which is important for the sensor optimization such as designing the winding geometry for the best linearity.

  15. Inductance position sensor for pneumatic cylinder

    Science.gov (United States)

    Ripka, Pavel; Chirtsov, Andrey; Mirzaei, Mehran; Vyhnanek, Jan

    2018-04-01

    The position of the piston in pneumatic cylinder with aluminum wall can be measured by external inductance sensor without modifications of the aluminum piston and massive iron piston rod. For frequencies below 20 Hz the inductance is increasing with inserting rod due to the rod permeability. This mode has disadvantage of slow response to piston movement and also high temperature sensitivity. At the frequency of 45 Hz the inductance is position independent, as the permeability effect is compensated by the eddy current effect. At higher frequencies eddy current effects in the rod prevail, the inductance is decreasing with inserting rod. In this mode the sensitivity is smaller but the sensor response is fast and temperature stability is better. We show that FEM simulation of this sensor using measured material properties gives accurate results, which is important for the sensor optimization such as designing the winding geometry for the best linearity.

  16. Topograph for inspection of engine cylinder walls.

    Science.gov (United States)

    Franz, S; Leonhardt, K; Windecker, R; Tiziani, H J

    1999-12-20

    The microstructural inspection of engine cylinder walls is an important task for quality management in the automotive industry. Until recently, mainly tactile methods were used for this purpose. We present an optical instrument based on microscopic fringe projection that permits fast, reliable, and nondestructive measurements of microstructure. The field of view is 0.8 mm x 1.2 mm, with a spatial sampling of 1100 x 700 pixels. In contrast to conventional tactile sensors, the optical method provides fast in situ three-dimensional surface characterizations that provide more information about the surface than do line profiles. Measurements are presented, and advantages of this instrument for characterization of a surface are discussed.

  17. Modeling a High Explosive Cylinder Experiment

    Science.gov (United States)

    Zocher, Marvin A.

    2017-06-01

    Cylindrical assemblies constructed from high explosives encased in an inert confining material are often used in experiments aimed at calibrating and validating continuum level models for the so-called equation of state (constitutive model for the spherical part of the Cauchy tensor). Such is the case in the work to be discussed here. In particular, work will be described involving the modeling of a series of experiments involving PBX-9501 encased in a copper cylinder. The objective of the work is to test and perhaps refine a set of phenomenological parameters for the Wescott-Stewart-Davis reactive burn model. The focus of this talk will be on modeling the experiments, which turned out to be non-trivial. The modeling is conducted using ALE methodology.

  18. Network design for cylinder gas distribution

    Directory of Open Access Journals (Sweden)

    Tejinder Pal Singh

    2015-01-01

    Full Text Available Purpose: Network design of the supply chain is an important and strategic aspect of logistics management. In this paper, we address the network design problem specific to packaged gases (cylinder supply chain. We propose an integrated framework that allows for the determination of the optimal facility locations, the filling plant production capacities, the inventory at plants and hubs, and the number of packages to be routed in primary and secondary transportation. Design/methodology/approach: We formulate the problem as a mixed integer program and then develop a decomposition approach to solve it. We illustrate the proposed framework with numerical examples from real-life packaged gases supply chain. The results show that the decomposition approach is effective in solving a broad range of problem sizes. Findings: The main finding of this paper is that decomposing the network design problem into two sub-problems is very effective to tackle the real-life large scale network design problems occurring in cylinder gas distribution by optimizing strategic and tactical decisions and approximating the operational decisions. We also benchmark the results from the decomposition approach by solving the complete packaged gases network design model for smaller test cases. Originality/value: The main contribution of our work is that it integrates supply chain network design decisions without fixing the fillings plant locations with inventory and resource allocation decisions required at the plants. We also consider the transportation costs for the entire supply chain including the transhipment costs among different facilities by deciding the replenishment frequency.

  19. Gravitational collapse of conventional polytropic cylinder

    Science.gov (United States)

    Lou, Yu-Qing; Hu, Xu-Yao

    2017-07-01

    In reference to general polytropic and conventional polytropic hydrodynamic cylinders of infinite length with axial uniformity and axisymmetry under self-gravity, the dynamic evolution of central collapsing mass string in free-fall dynamic accretion phase is re-examined in details. We compare the central mass accretion rate and the envelope mass infall rate at small radii. Among others, we correct mistakes and typos of Kawachi & Hanawa (KH hereafter) and in particular prove that their key asymptotic free-fall solution involving polytropic index γ in the two power exponents is erroneous by analytical analyses and numerical tests. The correct free-fall asymptotic solutions at sufficiently small \\hat{r} (the dimensionless independent self-similar variable) scale as {˜ } -|ln \\hat{r}|^{1/2} in contrast to KH's ˜ -|ln \\hat{r}|^{(2-γ )/2} for the reduced bulk radial flow velocity and as {˜ } \\hat{r}^{-1}|ln \\hat{r}|^{-1/2} in contrast to KH's {˜ } \\hat{r}^{-1} |ln \\hat{r}|^{-(2-γ )/2} for the reduced mass density. We offer consistent scenarios for numerical simulation code testing and theoretical study on dynamic filamentary structure formation and evolution as well as pertinent stability properties. Due to unavoidable Jeans instabilities along the cylinder, such collapsing massive filaments or strings can further break up into clumps and segments of various lengths as well as clumps embedded within segments and evolve into chains of gravitationally collapsed objects (such as gaseous planets, brown dwarfs, protostars, white dwarfs, neutron stars, black holes in a wide mass range, globular clusters, dwarf spheroidals, galaxies, galaxy clusters and even larger mass reservoirs etc.) in various astrophysical and cosmological contexts as articulated by Lou & Hu recently. As an example, we present a model scheme for comparing with observations of molecular filaments for forming protostars, brown dwarfs and gaseous planets and so forth.

  20. The influence of engine speed and load on the heat transfer between gases and in-cylinder walls at fired and motored conditions of an IDI diesel engine

    International Nuclear Information System (INIS)

    Sanli, Ali; Ozsezen, Ahmet N.; Kilicaslan, Ibrahim; Canakci, Mustafa

    2008-01-01

    In this study, the heat transfer characteristics between gases and in-cylinder walls at fired and motored conditions in a diesel engine were investigated by using engine data obtained experimentally. For this investigation, a four-cylinder, indirect injection (IDI) diesel engine was tested under different engine speeds and loads. The heat transfer coefficient was calculated by using Woschni expression correlated for the IDI diesel engines, and also using Annand and Hohenberg expressions. The temperature of in-cylinder gases were determined from a basic model based on the first law of thermodynamics after measuring in-cylinder pressure experimentally. The results show that the heat transfer characteristics of the IDI diesel engine strongly depend on the engine speed and load as a function of crank angle at fired and motored conditions