Journal articles: 'Core baffle'

1

Hagerty, James D. "Reinforced foam core acoustic baffle." Journal of the Acoustical Society of America 98, no. 3 (September 1995): 1255. http://dx.doi.org/10.1121/1.413530.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Chirkov, A., V. Kharchenko, and S. Kobelsky. "Assessment of WWER-1000 Core Baffle Form Alteration during Operation." Nuclear and Radiation Safety, no. 3(87) (September 15, 2020): 13–20. http://dx.doi.org/10.32918/nrs.2020.3(87).02.

Full text

Abstract:

The paper illustrates the results of the computer assessment of the form alteration in WWER-1000 core baffle obtained via the solution to the coupled thermoelastoplastic task considering the strains of irradiation growth and creep. In the modeling of the contact conditions, the temperature redistribution is considered due to the incompliance of the coolant flow in the contact zone between the core baffle and in-vessel core barrel with the design conditions. The modern approaches to the modeling of strains of the irradiation growth and irradiation creep in austenite steels are used in the space-limited environment under neutron exposure and elevated temperature. The finite element analysis involves the mixed scheme of the finite element method, which allows determination of the stress-strain state with high accuracy. The calculations are performed in the two-dimensional statement for the cross-section of the core baffle with the maximum damaging dose and irradiation temperature under the condition of the generalized plane strain. The results of the calculations are presented for full-scale reactor operation and scheduled shutdown to recharge the fuel cluster at the end of core life. The data on the distribution and value of the gap between the core baffle and barrel, as well as the spacer grids of the edge fuel assemblies and reactor core baffle edges, have been obtained from the median values of the dose dependence on swelling at different temperatures in Kh18N10T austenite steel.

APA, Harvard, Vancouver, ISO, and other styles

3

Abdullaiev, A., S. Soldatov, V. Hann, and S. Chernitskyi. "Calculation of Neutron Fluence and Energy Release in WWER-1000 Structural Components Using Monte Carlo Method." Nuclear and Radiation Safety, no. 1(77) (February 19, 2018): 11–17. http://dx.doi.org/10.32918/nrs.2018.1(77).02.

Full text

Abstract:

The paper describes the methodology for the calculation of neutron fluence and energy release in WWER-1000 reactor cavity and baffle using the Monte Carlo MCNPX code. It formulates an approach to the simulation of a 3-D neutron source and conditions for the transport of neutrons and photons in the core. The research presents preliminary results of neutron fluence and energy release calculation in WWER-1000 reactor cavity and baffle.

APA, Harvard, Vancouver, ISO, and other styles

4

Zhang, Enhui, Wenyan Zhu, and Lihe Wang. "Influencing analysis of different baffle factors on oil liquid sloshing in automobile fuel tank." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 13 (June 9, 2020): 3180–93. http://dx.doi.org/10.1177/0954407020919584.

Full text

Abstract:

Oil liquid sloshing is a common phenomenon in automobile fuel tank under variable working conditions. Installing baffles in automobile fuel tank is the most effective way to suppress adverse influence caused by oil liquid sloshing. Different types of three-dimensional finite element models filling oil liquid are created, meshed, and simulated. The reliability of simulation results is verified by test. The concept of time–area value is proposed in this work. In order to explore the influence of different baffle factors on oil liquid sloshing, six factors are studied. Six kinds of influencing factors are height, structure, shape, spacing, number, and placement of baffles. The sloshing pressure and time–area value are the core parameters for evaluating the influence degree. Some results could be obtained by comparing the parameters of oil liquid sloshing under the same condition. High baffles and baffles with small spacing have obvious attenuation influence on the pressure of oil liquid sloshing. Low baffles, double baffles, parallel baffles, and the combined action of inertia force and gravity are more beneficial to the reduction of time–area value. Time–area value is the largest and the smallest in fuel tank with intersection baffles and low baffles, respectively.

APA, Harvard, Vancouver, ISO, and other styles

5

TAHARA, Yoshihisa, Takashi KANAGAWA, and Hiroshi SEKIMOTO. "Two-Dimensional Baffle/Reflector Constants for Nodal Code in PWR Core Design." Journal of Nuclear Science and Technology 37, no. 11 (November 2000): 986–95. http://dx.doi.org/10.1080/18811248.2000.9714982.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Mirzov, I., and S. Kandala. "Method of Parametric Assignment of Input Data for Irradiation Swelling Calculation of VVER1000 Internals." Nuclear and Radiation Safety, no. 3(71) (August 15, 2016): 23–27. http://dx.doi.org/10.32918/nrs.2016.3(71).05.

Full text

Abstract:

Ukraine currently does not have a company to perform full neutronic calculations of VVER-1000 core. In this regard, the paper proposes a method of parametric assignment of volumetric heating due to gamma-radiation and the irradiation dose rate in VVER-1000 core baffle. The method significantly simplifies assessment of the stationary temperature, irradiation swelling and stress-strain state of pressure vessel internals. The method is based on the approximation of the input fields by polynomial s of nth degree in the radial and circumferential coordinates. Methodical error in the calculation of the stationary temperature field is 3,2 %, 12,7 % — in the calculation of radiation swelling, 33,0 % — in the evaluation of radial deformations of the core baffle. This allows to use the method for the preliminary assessment of technical condition of the VVER-1000 reactor internals.

APA, Harvard, Vancouver, ISO, and other styles

7

Margolin, B. Z., A. Ya Varovin, A. J. Minkin, D. A. Gurin, and V. A. Glukhov. "Investigation of irradiated metal of WWER-type reactor internals after 45 years of operation. Part 1. Research program and cutting out of samples from pressure vessel internals." Voprosy Materialovedeniya, no. 3(103) (November 30, 2020): 135–43. http://dx.doi.org/10.22349/1994-6716-2020-103-3-135-143.

Full text

Abstract:

The program is presented for investigations of the metal of the most irradiated elements of the WWER-440 reactor of the Novovoronezh NPP Unit 3 decommissioned after 45 years of operation. The fragments (cylindrical samples) were cut out from various zones of the core baffle and segment of forming ring of core barrel.

APA, Harvard, Vancouver, ISO, and other styles

8

Altstadt, E., H. Kumpf, F. P. Weiss, E. Fischer, G. Nagel, and G. Sgarz. "Analysis of a PWR core baffle considering irradiation induced creep." Annals of Nuclear Energy 31, no. 7 (May 2004): 723–36. http://dx.doi.org/10.1016/j.anucene.2003.10.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Fylonych, Yu, V. Zaporozhan, O. Balashevskyi, and K. Merkotan. "Analysis of the influence of nuclear fuel burnup on the 16N formation rate in the primary coolant of the WWER-1000 reactor." Nuclear Physics and Atomic Energy 22, no. 1 (March 25, 2021): 48–55. http://dx.doi.org/10.15407/jnpae2021.01.048.

Full text

Abstract:

The developed model of the WWER-1000 reactor using MCNP6.2 (Monte Carlo N-Particle Transport Code) includes the detailed core taking into account the design of the fuel assemblies, as well as the baffle, the lower plenum, the fuel support columns, the core barrel, a downcomer, and the reactor pressure vessel. It allows implementing multifunctional calculations such as recriticality with various fuel configurations, the critical concentration of boric acid, determination of the axial and radial peaking factor in the reactor core, etc. For obtaining the more precise result of the cumulation nitrogen-16 formation rate, the contribution from different water volumes was taken into account: in the core, above the fuel and the top nozzle, in the top nozzle of the fuel assembly, in the bottom nozzle, between the fuel and the bottom nozzle, in the axial channels of the baffle, in the reflector. In order to obtain the realistic boundary conditions, the change of the isotopic composition in the fuel assemblies during one fuel cycle was calculated using the ORIGEN-ARP of SCALE software. Therefore, the influence of the nuclear fuel depletion of fuel assemblies in the WWER-1000 reactor on the change of the basic neutron-physical characteristics was determined such as the distribution of the neutron flux density with the energies necessary to initiate the 16O(n,p)16N reaction, the average number of neutrons per fission, the neutron spectrum and average fission energy. As a result, the dependence of the nitrogen-16 formation rate in the primary coolant system on the nuclear fuel burnup is obtained.

APA, Harvard, Vancouver, ISO, and other styles

10

YONEZAWA, Toshio, Koji ARIOKA, Hiroshi KANASAKI, Koji FUJIMOTO, Kazuhide AJIKI, Takanori MATSUOKA, Sigeru URATA, and Hitoshi MIZUTA. "Intergranular Cracking Mechanism in Baffle Former Bolt Materials for PWR Core Internals." Journal of the Atomic Energy Society of Japan / Atomic Energy Society of Japan 42, no. 3 (2000): 212–17. http://dx.doi.org/10.3327/jaesj.42.212.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Filonov, V., Y. Filonova, Y. Dubyk, and A. Bohdan. "CALCULATION OF VVER-1000 CORE BAFFLE TEMPERATURE DISTRIBUTION FOR IT'S SWELLING ASSESSMENT." Odes’kyi Politechnichnyi Universytet Pratsi 1, no. 60 (2020): 35–46. http://dx.doi.org/10.15276/opu.1.60.2020.04.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Ren, Jian, C. H. Deng, and Q. Z. Hou. "Vibration and Sound Radiation of Truss Core Panels." Key Engineering Materials 334-335 (March 2007): 969–72. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.969.

Full text

Abstract:

The dynamic response and the sound radiation of truss core panels are investigated in this paper. The spectral element model for the truss core panel is developed. The element model is established by employing shape functions derived directly from the solution of distributed parameter models for each beam element. Forced vibrations of a fluid-loaded beam in a rigid baffle are considered. The spectral formulation can be easily and efficiently coupled with the Fourier transform (FT) based analysis of the structure’s sound radiation in a surrounding acoustic medium. Hence the proposed formulation is an efficient numerical tool for the analysis of the dynamic and acoustic performance of the considered truss core sandwich panels. The comparison of the sound characteristics selected as sound transmission reduction index to the psychical parameters of the truss core beam is carried out.

APA, Harvard, Vancouver, ISO, and other styles

13

Setiawan, Fathurrahman, Matthieu Lemaire, Hyunsuk Lee, Peng Zhang, and Deokjung Lee. "VVER-1000 BENCHMARK INTERPRETATION WITH MONTE CARLO CODE MCS." EPJ Web of Conferences 247 (2021): 10006. http://dx.doi.org/10.1051/epjconf/202124710006.

Full text

Abstract:

An interpretation of the NEA-1517/82 benchmark from the SINBAD shielding database has been conducted with the MCS Monte Carlo code developed at the Ulsan National Institute of Science and Technology (UNIST) and the ENDF/B-VII.1 nuclear data library. The NEA-1517/82 benchmark corresponds to experiments on a VVER-1000 critical mock-up (thermal reactor with hexagonal fuel lattice) inside the LR-0 research reactor operated by the Nuclear Research Institute (NRI) in the Czech Republic. A new 3D model of the VVER-1000 mock-up core is developed for MCS based on the SINBAD documentation. The model includes the top and bottom parts of fuel pins, the spacer grids and core components: baffle, barrel, downcomer, tank, reactor pressure vessel (RPV) and concrete block used as biological shielding. The quality of the model is verified first by code/code comparison of MCS against MCNP6 for criticality and power distributions (pin-by-pin and axial power). The validation of MCS results is then performed against six critical cases, 260 measured pin powers and benchmark calculations of the axial power profile. Finally, a comparison of calculated and measured neutron spectra inside the mock-up core is presented as a preliminary study for upcoming works on the deep-penetration shielding capability of MCS.

APA, Harvard, Vancouver, ISO, and other styles

14

Liu, Xian Ming, and Guo Ping Liu. "Study of a Lithium Battery Automatic Shell Control System Algorithm." Applied Mechanics and Materials 738-739 (March 2015): 1039–47. http://dx.doi.org/10.4028/www.scientific.net/amm.738-739.1039.

Full text

Abstract:

set of shell is an important process on lithium battery production line. Research is applicable to automatic set of lithium battery shell of an organization, the installed baffle set into the very core of battery shell, do not harm the very core, set into the very core of the exposed aluminum shell of the same length. This article put forward from the aspects of kinematics and dynamics of multiple optimization objectives, work in a given space and a variety of constraint conditions, with the aid of the NSGA - II algorithm to complete set of shell machine structure parameters optimization, experiments show that the casing precision of the equipment, set of shell and the percent of pass is up to 99 above, has a certain practical significance.

APA, Harvard, Vancouver, ISO, and other styles

15

Gao, Dian Rong, Jian Hua Zhao, and Song Lin Zhou. "Performance Analysis of Double Nozzle Flapper Servo Valve Based on Liquid-Solid Couple Effect and Moving Grid Approach." Applied Mechanics and Materials 779 (July 2015): 13–25. http://dx.doi.org/10.4028/www.scientific.net/amm.779.13.

Full text

Abstract:

When designing the servo valve with different structure parameters, the influence of the interaction between the liquid and the solid on the performance of servo valve can only be obtain by the method of experiment, and then it can increase the time and cost of designing the servo valve. The liquid-solid couple method can obtain the influence of structure parameters on the performance of servo valve under the circumstance of reducing the experimental cost and time. The paper chooses the servo valve of A and B as models for study, The text adopts FSI method to analyze the flow field of double nozzle baffle electro-hydraulic servo valve prestage through the software of ANSYS, research the change of the prestage flow field by deflection of loaded armature baffle components, contrast and analyze the change of velocity, pressure, power loss and flow coefficient of fixed choke, nozzle, return port, and the displacement of the valve core of slide valve, stress of armature baffle components, pressure at both ends of spool. Summarize the advantages and disadvantages of A and B servo valve, and find different parameters of servo valve have different performance, it is difficult to find a common structure and size. It can help us to select the requirement structure by using fluid-structure interaction, reduce experiments and save cost.

APA, Harvard, Vancouver, ISO, and other styles

16

Mikuš, Ján. "Power Distribution and Possible Influence on Fuel Failure in WWER-1000." Science and Technology of Nuclear Installations 2008 (2008): 1–5. http://dx.doi.org/10.1155/2008/753091.

Full text

Abstract:

The work is focused on the influence of investigation of some core heterogeneities and construction materials on the space power (fission rate) distribution in WWER-1000-type cores, especially from viewpoint of the values and gradient occurrence that could result in static loads with some consequences, for example, fuel pin (FP) or fuel assembly (FA) bowing and possible contribution to the FP failure root causes. For this purpose, experimental data and their analysis from two earlier performed measurements on light water, zero-power reactor LR-0 were used, concerning the relative radial power distribution determined by measurements in a WWER-1000-type core containing single FPs with homogeneous gadolinium admixture () and the relative radial power distribution determined by measurements in FA situated on the periphery of a WWER-1000-type core neighbouring the baffle (thermal shielding).

APA, Harvard, Vancouver, ISO, and other styles

17

Rupp, Isabelle, Christophe Peniguel, and Michel Tommy-Martin. "LARGE SCALE FINITE ELEMENT THERMAL ANALYSIS OF THE BOLTS OF A FRENCH PWR CORE INTERNAL BAFFLE STRUCTURE." Nuclear Engineering and Technology 41, no. 9 (November 30, 2009): 1171–80. http://dx.doi.org/10.5516/net.2009.41.9.1171.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Sahel, Djamel, Houari Ameur, and Touhami Baki. "Effect of the size of graded baffles on the performance of channel heat exchangers." Thermal Science 24, no. 2 Part A (2020): 767–75. http://dx.doi.org/10.2298/tsci180326295s.

Full text

Abstract:

The baffling technique is well-known for its efficiency in terms of enhancement of heat transfer rates throught channels. However, the baffles insert is accompanied by an increase in the friction factor. This issue remains a great challenge for the designers of heat exchangers. To overcome this issue, we suggest in the present paper a new design of baffles which is here called graded baffle-design. The baffles have an up- or down-graded height along the channel length. This geometry is characterized by two ratios: up-graded baffle ratio and down-graded baffle ratio which are varied from 0-0.08. For a range of Reynolds number varying from 104 to 2 ? 104, the turbulent flow and heat transfer characteristics of a heat exchanger channel are numerically studied by the computer code FLUENT. The obtained results revealed an enhancement in the thermohydraulic performance offered by the new suggested design. For the channel with a down-graded baffle ratio equal to 0.08, the friction factors decreased by 4-8%

APA, Harvard, Vancouver, ISO, and other styles

19

Wang, He Tang, De Ming Wang, and Wan Xing Ren. "Computer Simulation on Key Structure Parameters of Foam Generator for Dust Control in Underground Coal Mines." Advanced Materials Research 466-467 (February 2012): 421–24. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.421.

Full text

Abstract:

Foam is a high efficient technology for controlling dust in underground coal mine,and foam generator is one of the core components of the technology. Aiming at designing the key structural parameters of foam generator scientifically, the velocity and pressure distribution of foam generator under different parameters were simulated and displayed by CFD (Computational Fluid Dynamics) software. The results show that the intensity of gas-liquid mixture in foam generator reaches the maximum when the vortex generator is 24mm away from the throat and the baffle with a 45° angle. Under the circumstances, the pressure is well-distributed around the vortex generator and the outlet of foam generator, and the foaming effect best.

APA, Harvard, Vancouver, ISO, and other styles

20

Su, Qi, Weiran Chen, Weiping Chen, Zhijiang Jin, and Zhenhao Lin. "Flow Regulation Performance Analysis of Microfluidic Passive Valve for High Throughput Liquid Delivery." Micromachines 13, no. 5 (April 28, 2022): 687. http://dx.doi.org/10.3390/mi13050687.

Full text

Abstract:

A microfluidic passive valve (MPV) is important for precise flow control, and it determines the reliability of the microfluidic system. In this paper, a novel MPV capable of delivering a constant flow rate independently of inlet pressure changes is proposed. The flow rate of the MPV is adjusted by the difference between the fluid force on the upper surface of the valve core and the spring force. The constant flow rate of the MPV is maintained by automatically changing the size of the gap channel formed by the groove on the valve core and the baffle on the valve body. The nearly constant flow rate of the MPV is 6.26 mL/min, with a variation of 6.5% under the inlet pressure varied from 1.25 kPa to 3.5 kPa. In addition, the flow characteristics of the MPV are analyzed by numerical simulation. With the increase in the inlet pressure, the maximum velocity gradually increases, while the increment of the maximum velocity decreases. In the movement process of the valve core, the region of pressure drop becomes larger. This work has a certain reference value for the design and research of the MPVs with high throughput liquid delivery.

APA, Harvard, Vancouver, ISO, and other styles

21

Gruel, A., K. Ambrožič, C. Destouches, V. Radulović, A. Sardet, and L. Snoj. "Gamma-heating and gamma flux measurements in the JSI TRIGA reactor, results and prospects." EPJ Web of Conferences 225 (2020): 04029. http://dx.doi.org/10.1051/epjconf/202022504029.

Full text

Abstract:

The neutron field of various irradiation positions of the TRIGA Mark II reactor of the Jožef Stefan Institute has been thoroughly characterized by neutron activation dosimetry and miniature fission chambers techniques. In order to have a fully validated calculation scheme to analyze and plan experiments, the gamma field also has to be experimentally validated. The 10-year long collaboration between CEA and JSI is a perfect framework to carry out such a study, and measurements of the gamma field started in late 2016. Several measurement techniques were investigated in in-core and ex-core positions. On-line measurements were carried out using miniature ionization chambers manufactured by the CEA and PTW Farmer ionization chambers. Positional dependence was studied, showing a decrease in the delayed gamma contribution to the total gamma flux with increasing distance from the reactor core center. To characterize the gamma dose in the core, as well as in the periphery, thermo- and optically stimulated luminescent detectors were tested. These detectors are commonly used at CEA to measure the gamma dose in a given material in order to study the nuclear heating in various core elements (control rod, baffle, structural material). Different filters were used in order to assess an integrated dose ranging from a few Gy up to several kGy. The feasibility of such measurements demonstrates the complementarity between measurements with dosimetry and ionization chambers from low to very high gamma-dose environment, such as in material testing reactors.

APA, Harvard, Vancouver, ISO, and other styles

22

Haddar, Mohamed, Moez Hammami, and Mounir Baccar. "Numerical study of steady natural convection in a liquefied natural gas cylindrical storage tank equipped with baffles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 5 (August 27, 2019): 709–21. http://dx.doi.org/10.1177/0957650919870927.

Full text

Abstract:

In this paper, a study of cooling system for a liquefied natural gas storage tank is conducted. Our objective is to remedy the heat ingress to the liquefied natural gas from the environment using baffles toward limiting temperature elevation in the tank, and then the Boil-off Gas (BOG) formation. A specific code based on the finite volume method is developed to supply a fine knowledge of the hydrodynamic and thermal liquefied natural gas characteristics in the cylindrical tank heated from bottom and lateral surfaces. The effect of the number, position and dimension of baffles, on the flow structure and thermal behavior, has been analyzed. According to our simulation results, the baffles should be placed at the top of tank nearby the lateral wall as the liquefied natural gas dimensionless average temperature can be reduced by 36%. The installation of four rectangular baffles, equally spaced around the perimeter of the tank, gives better homogenization of the temperature field and decreases the average temperature by about 44% in order to limit BOG formation. Finally, two correlations of the Nusselt number are established for the flat rectangular baffle plates and the lateral surface of the cylindrical liquefied natural gas storage tank as a function of the Rayleigh number, as well as the baffle number. Scaling of these correlations with the Rayleigh number gives exponents of 0.25 and 0.18 for lateral surface and baffle, respectively, which are in good agreement with literature.

APA, Harvard, Vancouver, ISO, and other styles

23

Teplukhina, Irina, Anton Tsvetkov, and Anastasiya Kosulnikova. "The effect of quenching parameters on the structure and properties of radiation-resistant austenitic steel for the VVER core baffle." Letters on Materials 10, no. 2 (2020): 179–84. http://dx.doi.org/10.22226/2410-3535-2020-2-179-184.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

BEERBOHM, ERIC. "Is Democratic Leadership Possible?" American Political Science Review 109, no. 4 (November 2015): 639–52. http://dx.doi.org/10.1017/s0003055415000398.

Full text

Abstract:

Leadership can baffle our ideal of democracy. If representatives track our preferences, actual or ideal, what room is left for them to pushback against a constituency? This has led some political theorists to conclude that the concept of democratic leadership is paradoxical. I challenge this view by constructing a theory that takes shared commitment as its principal ingredient. The Commitment Theory brings out what is morally distinctive about leadership in a representative democracy. In principle, democratic leadership recruits citizens as genuine partners in shared political activity. The account explains why leadership is taken to be a core property of a functioning democracy and, at the same time, a potential threat to the practice. It is then tested against cases of opinion formation, cue-taking, and frame manipulation. I conclude that the theory avoids dual objections: that it either overcounts or undercounts instances of democratic leadership.

APA, Harvard, Vancouver, ISO, and other styles

25

Tsvetkov, Anton Sergeevich, and Irina Vladimirovna Teplukhina. "Homogenization of Cr-Ni Austenitic Steel Studying: Liquation and Microhardness Heterogeneity Equalization." Key Engineering Materials 822 (September 2019): 53–59. http://dx.doi.org/10.4028/www.scientific.net/kem.822.53.

Full text

Abstract:

Currently, a new generation of pressurized water reactor for nuclear power plants with an extended service life (up to 60 years) and a guarantee of their complete safety are being designed in Russia. Analysis of the reactor internal elements performance showed, that designed service life cannot be guaranteed if the reactor’s internal parts would be made from currently used stainless steel (18-10 alloy type). Instead of the used steel, to ensure operability, new austenitic stainless steel (16-25 alloy type), with increased resistance to radiation swelling, is being developed for production of forged ring blanks for core baffle. The use of new steel requires revision of the existing metallurgical production technology stages. Therefore in this paper diffusion experiment was carried out to determine the required duration of homogenization. The results are presented in terms of different duration of the high-temperature exposure effect on the liquation heterogeneity equalization. The relation between duration of homogenization and microhardness is also shown.

APA, Harvard, Vancouver, ISO, and other styles

26

Chirkov, A. Yu, and V. V. Kharchenko. "Special Features of Computational Assessment of the Change in Shape of WWER-1000 Reactor Core Baffle in View of Irradiation-Induced Swelling." Strength of Materials 52, no. 3 (May 2020): 339–52. http://dx.doi.org/10.1007/s11223-020-00184-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Zhemzhurov, M. L., G. M. Zhmura, I. E. Rubin, G. Z. Serebryany, N. M. Dneprovskaya, N. A. Tetereva, I. V. Rudenkov, and L. F. Babichev. "Calculation researches for the formation of high-level and long-life medium-level radioactive waste of activation origin for the WWER-1200 reactor of Belarusian NPP." Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 66, no. 3 (October 12, 2021): 365–77. http://dx.doi.org/10.29235/1561-8358-2021-66-3-365-377.

Full text

Abstract:

The study of the issue of constructing a disposal facility for high-activity radioactive waste in the Republic of Belarus is associated with an assessment of the volume of radioactive waste to be deeply disposed of, generated as a result of the activation of structural materials of the VVER-1200 reactor of the Belarusian NPP. This paper presents the results of computational studies of the formation of solid high-level radioactive waste (HLW) and long-lived intermediate level radioactive waste (ILW-LL) during neutron activation of materials adjacent to the core of the VVER-1200 reactor structures of the Belarusian NPP. The assessment of the volumes of HLW and ILW-LL of activation origin, formed over 60 years of operation of the VVER-1200 reactor, was carried out on the basis of computational studies of the induced activity of structural and shielding materials using reactor and Monte Carlo program codes (SERPENT 2, TVS-M, DYN3D, MCU- PD). As a result of the research, it was found that when neutrons activate materials of the sections of the VVER-1200 reactor structures of the Belarusian NPP adjacent to the core (in the steel structures of the baffle, shaft, surfacing, part of the reactor vessel, structures of the protective tube unit (PTU), the space under the core, in heat insulation materials, rods of absorbing elements (Dy2TiO5)) are formed by HLW and ILW-LL with a total weight of 272,5 tons and a volume of 43 m3 . Calculated studies of the activation of dry protection materials, building concrete, support truss and biological protection showed that these structural elements will not belong to either HLW or ILW-LL.

APA, Harvard, Vancouver, ISO, and other styles

28

Haddar, Mohamed, Moez Hammami, and Mounir Baccar. "Numerical parametric study of a cooling system for an LNG storage tank." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74 (2019): 21. http://dx.doi.org/10.2516/ogst/2018097.

Full text

Abstract:

The study of the cooling system of a Liquefied Natural Gas (LNG) storage tank is vital for the safety of the installation. The objective of this paper is to develop cooling baffles capable of reducing the heat gain from the environment leading to a loss of LNG quantity, keeping the Boil-Off Gas (BOG) under control. For this purpose, a specific code based on the finite volume method was developed to improve our knowledge of the hydrodynamic and thermal behaviors of LNG in the cylindrical tank. In addition, the effect of the number, position and dimension of the baffles on the flow structure of LNG were determined. The obtained results indicated that the location of the baffles at the top of the tank nearby the vicinity of the wall would yield a better cooling of the LNG. Moreover, we emphasized that a number of six baffles would give rise to a better heat transfer. For a design purpose, the Nusselt numbers on the lateral surface and on the baffles have been correlated as functions of Rayleigh and baffle numbers.

APA, Harvard, Vancouver, ISO, and other styles

29

Moessner, David P. "Paul in Acts: Preacher of Eschatological Repentance to Israel." New Testament Studies 34, no. 1 (January 1988): 96–104. http://dx.doi.org/10.1017/s0028688500022232.

Full text

Abstract:

The ‘enigmatic ending’ of Acts continues to baffle the exegetes. Not the least of its difficulties is the status of ‘the Jews’ after Paul's peculiarly solemn pronouncement of Isa 6. 9–10 against a ‘closed’ and ‘hardened’ people (Acts 28. 26–27). Coming as it does as a climax to the equally ponderous pronouncements of judgment in Acts 13. 46 and 18. 6, for many scholars the cumulative, three-fold impact of this indictment resounds a note of finality, of foreclosure upon Israel which consequently consummates an era and looks ahead almost exclusively to a Gentile church. The two leading clusters of opinion expressing this understanding are those associated with E. Haenchen – viz., that repentance for Israel by the end of Acts is de facto now over, with Gentiles replacing Jews as the people of God – or with J. Jervell – that a core of repenting Jews constitutes a restored Israel which, along with increasing numbers of Gentiles, by the end of chapter 28 has completed its mission to unrepenting Jews who no longer have a right to the name ‘Israel’ or ‘people of God’.

APA, Harvard, Vancouver, ISO, and other styles

30

KAMEYAMA, Masashi, Naoki CHIGUSA, Noboru KUBO, and Masaaki KATAYAMA. "Irradiation creep and IASCC prediction method of PWR's core internal-Verification of "Inspection and Evaluation Guideline for Reactor Internals of PWR (Baffle Former Bolt)"-." QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY 23, no. 1 (2005): 77–81. http://dx.doi.org/10.2207/qjjws.23.77.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Andrzejczyk, R., and T. Muszynski. "An experimental investigation on the effect of new continuous core-baffle geometry on the mixed convection heat transfer in shell and coil heat exchanger." Applied Thermal Engineering 136 (May 2018): 237–51. http://dx.doi.org/10.1016/j.applthermaleng.2018.03.003.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Kremeyer, Thierry, R. König, S. Brezinsek, O. Schmitz, Y. Feng, V. Winters, L. Rudischhauser, et al. "Analysis of hydrogen fueling, recycling, and confinement at Wendelstein 7-X via a single-reservoir particle balance." Nuclear Fusion 62, no. 3 (March 1, 2022): 036023. http://dx.doi.org/10.1088/1741-4326/ac4acb.

Full text

Abstract:

Abstract A single-reservoir particle balance for the main plasma species hydrogen has been established for W7-X. This has enabled the quantitative characterization of the particle sources in the standard island divertor configuration for the first time. Findings from attached scenarios with two different island sizes with a boronized wall and turbo molecular pumping are presented. Fueling efficiencies, particle flows and source locations were measured and used to infer the total particle confinement time τ p. Perturbative gas injection experiments served to measure the effective particle confinement time τ p * . Combining both confinement times provides access to the global recycling coefficient R ¯ . Hydrogen particle inventories have been addressed and the knowledge of particle sources and sinks reveals the core fueling distribution and provides insight into the capability of the magnetic islands to control exhaust features. Measurements of hydrogen fueling efficiencies were sensitive to the precise fueling location and measured between 12% and 31% with the recycling fueling at the strike line modeled at only 6%, due to much higher densities. 15% of the total 5.2 × 1022 a/s recycling flow ionizes far away from the recycling surfaces in the main chamber. It was shown that 60% of recycled particles ionize above the horizontal and 18% above the vertical divertor target, while the remainder of the recycling flow ionizes above the baffle (7%). Combining these source terms with their individual fueling efficiencies resolves the core fueling distribution. Due to the higher fueling efficiency in the main chamber, up to 51% of the total 5.1 × 1021 s−1 core fueling particles are entering the confined plasma from the main chamber. τ p values in the range of 260 ms were extracted for these discharges. Together with τ p, the global recycling coefficient R ¯ was resolved for every τ p * measurement and a typical value close to unity was obtained. An increase of the island size, resulted in no change of τ p, but doubled τ p * , indicating the feasibility of the control coils as an actuator to control exhaust features without affecting core confinement properties.

APA, Harvard, Vancouver, ISO, and other styles

33

Yang, Sun Choel, Geon Hee Kim, Myung Sang Huh, Sang Yong Lee, Sang Hyuk Kim, and Gil Jae Lee. "Ultra Precision Machining of the Winston Cone Baffle for Space Observation Camera." Key Engineering Materials 516 (June 2012): 42–47. http://dx.doi.org/10.4028/www.scientific.net/kem.516.42.

Full text

Abstract:

The Winston cone baffle was developed for the space observation camera of the MIRIS (Multi-purpose Infrared Imaging System) which is the main payload of STSAT-3 (Science and Technology Satellite). The Winston cone baffle reduces the orbital heat load to the STSAT-3 and is thermally connected to the radiator to cool down. The jig and ultra precision machining jig was designed using a 3D modelling program and analyzed using a computer aided engineering program (ANSYS). The reasons for designing the jig for the baffle were to enhance the stability of the machining and improve the form accuracy of the baffle. The strength, weight and barycentre of the jig are investigated to find the optimized ultra precision machining conditions. To maintain the weight balance of the baffle at high speed rotation, there are lots of holes that can be inserted by heavier bolts. Vibration of the natural diamond bite tool is reduced by using thin copper pipe and urethane silicone. Using this bite tool, we could decrease patterns on the surface of the Winston cone baffle. The results of the simulation using ANSYS show that maximum deformation of the baffle is less than the tolerance limit. Surface roughness of the fabricated Winston cone baffle is machined with the jig and the machining tool is under 5 nm. The Winston cone baffle is plated with gold after being electroless plated with nickel. This baffle is applied to the flight model of the MIRIS.

APA, Harvard, Vancouver, ISO, and other styles

34

Tian, Haowen, Shixu Guo, Peng Zhao, Minyu Gong, and Chao Shen. "Design and Implementation of a Real-Time Multi-Beam Sonar System Based on FPGA and DSP." Sensors 21, no. 4 (February 18, 2021): 1425. http://dx.doi.org/10.3390/s21041425.

Full text

Abstract:

Aiming at addressing the contradiction between the high-speed real-time positioning and multi-channel signal processing in multi-beam sonar systems, in this work we present a real-time multi-beam sonar system based on a Field Programmable Gate Array (FPGA) and Digital Signal Processing (DSP) from two perspectives, i.e., hardware implementation and software optimization. In terms of hardware, an efficient high-voltage pulse transmitting module and a multi-channel data acquisition module with time versus gain (TVG) compensation with characteristics such as low noise and high phase amplitude consistency, are proposed. In terms of algorithms, we study three beamforming methods, namely delay-and-sum (D&S), direct-method (DM) and Chirp Zeta Transform (CZT). We compare the computational efficiency of DM and CZT in the digital domain. In terms of software, according to the transmission bandwidth of the Gigabit Ethernet and a serial rapid IO (SRIO) interface, the data transmission paths of the acquired data and the beam pattern between the FPGA, the DSP, and a personal computer (PC) are planned. A master-slave multi-core pipelined signal processing architecture is designed based on DSP, which enhances the data throughput of the signal processor by seven times as compared with that of the single-core operation. The experimental results reveal that the sound source level of the transmitting module is around 190.25 dB, the transmitting beam width is 64° × 64°, the background noise of the acquisition module is less than 4 μVrms, the amplitude consistency error of each channel is less than −6.55 dB, and the phase consistency error is less than 0.2°. It is noteworthy that the beam number of the sonar system is 90 × 90, the scanning angle interval is 0.33°, the working distance ranges from 5 m to 40 m, and the maximum distance resolution is 0.384 m. In the positioning experiment performed in this work; the 3-D real-time position of the baffle placed in the detection sector is realized. Please note that the maximum deviation of azimuth is 2°, the maximum deviation of elevation is 2.3°, and the maximum distance deviation is 0.379 m.

APA, Harvard, Vancouver, ISO, and other styles

35

Woillez, Marie-Noëlle, Christine Souque, Jean-Luc Rudkiewicz, Françoise Willien, and Tristan Cornu. "Insights in Fault Flow Behaviour from Onshore Nigeria Petroleum System Modelling." Oil & Gas Sciences and Technology – Revue d’IFP Energies nouvelles 72, no. 5 (September 2017): 31. http://dx.doi.org/10.2516/ogst/2017029.

Full text

Abstract:

Faults are complex geological features acting either as permeability barrier, baffle or drain to fluid flow in sedimentary basins. Their role can be crucial for over-pressure building and hydrocarbon migration, therefore they have to be properly integrated in basin modelling. The ArcTem basin simulator included in the TemisFlow software has been specifically designed to improve the modelling of faulted geological settings and to get a numerical representation of fault zones closer to the geological description. Here we present new developments in the simulator to compute fault properties through time as a function of available geological parameters, for single-phase 2D simulations. We have used this new prototype to model pressure evolution on a siliciclastic 2D section located onshore in the Niger Delta. The section is crossed by several normal growth faults which subdivide the basin into several sedimentary units and appear to be lateral limits of strong over-pressured zones. Faults are also thought to play a crucial role in hydrocarbons migration from the deep source rocks to shallow reservoirs. We automatically compute the Shale Gouge Ratio (SGR) along the fault planes through time, as well as the fault displacement velocity. The fault core permeability is then computed as a function of the SGR, including threshold values to account for shale smear formation. Longitudinal fault fluid flow is enhanced during periods of high fault slip velocity. The method allows us to simulate both along-fault drainages during the basin history as well as overpressure building at present-day. The simulated pressures are at first order within the range of observed pressures we had at our disposal.

APA, Harvard, Vancouver, ISO, and other styles

36

Savino, Stefano, and Carlo Nonino. "Header Shape Effect on the Inlet Velocity Distribution in Cross-Flow Double-Layered Microchannel Heat Sinks." Fluids 7, no. 1 (December 24, 2021): 7. http://dx.doi.org/10.3390/fluids7010007.

Full text

Abstract:

Counter-flow double-layered microchannel heat sinks are very effective for thermal control of electronic components; however, they require rather complicated headers and flow maldistribution can also play a negative role. The cross-flow configuration allows a much simpler header design and the thermal performance becomes similar to that provided by the counter-flow arrangement if the velocity distribution in the microchannels is not uniform. The aim of this work is to show the possibility of achieving a favorable flow distribution in the microchannels of a cross-flow double-layered heat sink with an adequate header design and the aid of additional elements such as full or partial height baffles made of solid or porous materials. Turbulent RANS numerical simulations of the flow field in headers are carried out with the commercial code ANSYS Fluent. The flow in the microchannel layers is modeled as that in a porous material, whose properties are derived from pressure drop data obtained using an in-house FEM code. It is demonstrated that, with an appropriate baffle selection, inlet headers of cross-flow microchannel heat sinks yield velocity distributions very close to those that would allow optimal hotspot management in electronic devices.

APA, Harvard, Vancouver, ISO, and other styles

37

Misyulya, D. I. "Cone lamellated baffle with guide plates." Russian Journal of Applied Chemistry 83, no. 9 (September 2010): 1676–78. http://dx.doi.org/10.1134/s107042721009034x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Milligan, Paul A., James W. Rector, and Robert W. Bainer. "Hydrophone VSP imaging at a shallow site." GEOPHYSICS 62, no. 3 (May 1997): 842–52. http://dx.doi.org/10.1190/1.1444193.

Full text

Abstract:

We evaluated the capabilities of vertical seismic profiling (VSP) for imaging the complex heterogeneous unconsolidated sedimentary structures at a shallow site. We deployed a 24‐level hydrophone array with 0.5-m level spacing down a preexisting poly vinyl chloride (PVC) cased well. Data acquisition time was quick. Only 15 multioffset shot points using a hammer‐on‐plate source were needed to acquire reflection data between the water table at 3 m and the bedrock at 35 m to produce a depth section image. This image extended 9 m from the receiver well, yielding resolutions between fresh‐water‐bearing sands and impermeable muds and clays of better than 1 m. Depth accuracy of the image was confirmed by good correlation with cone penetrometer logs. We used conventional wavefield separation and VSP-CDP mapping techniques to image the data. Tube waves, created by seismic arrivals at cross‐sectional area changes in the borehole fluid column, were the primary source of coherent noise in the data. The tube‐wave arrival structure was complicated by the hydrophone array, which generated and scattered tube waves at each hydrophone pod. To combat the tube wave interference, we inserted closed‐cell‐foam baffles between elements. The baffles attenuated and slowed the tube waves, and reduced generation and scattering. A comparison between unbaffled and baffled VSP data showed that baffling increased the maximum useful frequency from 300 Hz to over 900 Hz. By contrast, surface shot data recorded at the same site, using buried 40-Hz vertical geophones, exhibited useful frequencies of less than 250 Hz. In addition, coherent noise in surface shot records caused by air waves and first arrivals made it very difficult to identify shallow reflections above 25 m. Reflections from depths as shallow as 10 m were easy to identify in the baffled VSP data.

APA, Harvard, Vancouver, ISO, and other styles

39

Jin, Mei, Li Zhan, Han Lin Wu, and Hong Jiao Liu. "Structure Size on the Heat Transfer Performance of Shell and Tube Heat Exchanger." Applied Mechanics and Materials 778 (July 2015): 37–40. http://dx.doi.org/10.4028/www.scientific.net/amm.778.37.

Full text

Abstract:

In this paper, based on the numerical simulation with RNG k-ε model by using commercial code of FLUENT, the effects of the structure size of the shell and tube heat exchanger, such as the baffle spacing and the gap height of baffle plate, on the pressure drop, the heat transfer coefficient and j-f Factor were investigated to obtain the relationship between the baffle spacing and the gap height of baffle plate using the same thermophysical conditions. The numerical simulation results exhibited that there was a non-monotonic relationship between the baffle spacing and the gap height of baffle plate. A better heat transfer performance could be observed under the condition of a smaller value of the baffle spacing and a higher value of the ratio of the gap height to the actual section, or under the condition of a higher value of the baffle spacing and a smaller value of the ratio of the gap height to the actual section. Moreover, under the optimum geometrical condition, the numerical simulation results showed that a smaller difference between the inlet section length and the baffle spacing could give a higher j-f Factor and a better heat transfer performance.

APA, Harvard, Vancouver, ISO, and other styles

40

Laroche, S., L. Sun, and J. Pietralik. "NUMERICAL ANALYSIS OF CAVITATION SUSCEPTIBILITY FOR STEAM GENERATOR INTEGRAL PREHEATER TUBES." AECL Nuclear Review 3, no. 01 (June 1, 2014): 37–46. http://dx.doi.org/10.12943/anr.2014.00026.

Full text

Abstract:

A new tube degradation mechanism was observed in a recirculating steam generator (SG) with an integral preheater tube at the clearance gap between the tube and the preheater baffle. The general pattern of the damage and material composition in the degraded region suggested that the degradation was cavitation erosion. Cavitation erosion occurs when vapour bubbles exist or form in the flowing liquid and then these bubbles collapse violently in the vicinity of a solid wall. The bubbles collapse when they contact water that is sufficiently subcooled, i.e., below the saturation temperature. In the clearance gap between the tube and the preheater baffle, secondary fluid flow exists due to the pressure difference across the baffle plate. Meanwhile, heat transfer occurs from the primary-side fluid to the secondary-side fluid within this clearance gap, driven by the primary-to-secondary temperature difference. Factors such as the tube position in the baffle hole and fouling may influence the local flow and heat transfer conditions and can cause subcooled boiling that results in cavitation. This paper presents a numerical analysis of flow and heat transfer phenomena to determine the factors contributing to cavitation erosion of tubes in the preheater of a recirculating SG. The analysis used the THIRST code for a 3-dimensional thermalhydraulic simulation of steam generator and the ANSYS Fluent® code for detailed calculations of flow and heat transfer in the clearance gaps. A detailed temperature distribution in the gap was obtained using this analysis to determine the regions where subcooled boiling could occur by comparing the local fluid temperature with its saturation temperature. The susceptibility to cavitation was found to increase with increased inclination (i.e., tilt) and eccentricity (i.e., off-centre) of the tube in the baffle plate gap, and increased fouling on baffle plate surfaces. This methodology could be applied to analyze the cavitation susceptibility for other preheater types with this “tube to baffle plate” gap, as these preheaters might have conditions where boiling followed by the rapid condensation of the steam bubbles are present.

APA, Harvard, Vancouver, ISO, and other styles

41

Hao, Zong Rui, Juan Xu, Hai Yan Bie, and Zhong Hai Zhou. "Study of Flow Characteristics of Oil and Water in the Process of Stirring." Applied Mechanics and Materials 353-356 (August 2013): 3190–93. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.3190.

Full text

Abstract:

To study the flow pattern in the process of oil-water stirring in three paddle stirring tank, RNG k-ε turbulent model and VOF model are adopted to simulate the flow field at different time in the stirred tank with the baffle. The results showed that, in the stirring process, inverted cone manifold was formed in the center of the stirring shaft. The stratified area was formed in the baffle and gradually transported to the bottom of the tank. The two circular flows were formed among three groups of blades. And the axially acting of the fluid was strong, which made homogeneous stirring in the stirred tank. At the same time the radial flow of the cross-section inside the tank increased because of the baffle.

APA, Harvard, Vancouver, ISO, and other styles

42

Li, Jie. "Numerical Research in Effects of Baffles on Heat Transfer Characteristics of a Tunnel Kiln’s Flue Gas Heat Exchanger." Advanced Materials Research 953-954 (June 2014): 911–14. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.911.

Full text

Abstract:

In order to investigate effects of baffles on heat transfer characteristics of a tunnel kiln’s flue gas heat exchanger, the flow fields and temperature fields in two exchangers, one with baffles and the other without, under operative conditions, are separately simulated by using FLUENT code. According to simulation results, average temperature at the air outlet and average pressure at the air inlet of the exchanger with baffles are separately 67.2°C and 265 Pa, and those in the case of the exchanger without baffles are respectively 60.4°C and 240 Pa. Reasons why the baffles exert high influence on heat transfer characteristics of the exchanger are analyzed. On basis of the data and analysis, two conclusions are drawn: (1) Installation of baffles exerts high influence on heat transfer characteristics of the heat exchanger studied. (2) The reason why the baffles could exert such influence is that the baffles prevent much air from flowing into external zones of the baffles, so in per unit time more air exchanges heat energy with hot walls of heat exchange tubes, which are in internal zones of the baffles.

APA, Harvard, Vancouver, ISO, and other styles

43

Osterberg, Erich C., Robert L. Hawley, Gifford Wong, Ben Kopec, David Ferris, and Jennifer Howley. "Coastal ice-core record of recent northwest Greenland temperature and sea-ice concentration." Journal of Glaciology 61, no. 230 (2015): 1137–46. http://dx.doi.org/10.3189/2015jog15j054.

Full text

Abstract:

AbstractCoastal ice cores provide an opportunity to investigate regional climate and sea-ice variability in the past to complement hemispheric-scale climate reconstructions from ice-sheet-interior ice cores. Here we describe robust proxies of Baffin Bay temperature and sea-ice concentration from the coastal 2Barrel ice core collected in the Thule region of northwest Greenland. Over the 1990–2010 record, 2Barrel annually averaged methanesulfonic acid (MSA) concentrations are significantly correlated with May–June Baffin Bay sea-ice concentrations and summer temperatures. Higher MSA is observed during warmer years with less sea ice, indicative of enhanced primary productivity in Baffin Bay. Similarly, 2Barrel annually averaged deuterium excess (d-excess) values are significantly correlated with annual Baffin Bay sea-ice concentrations and summer and annual temperatures. Warm (cool) years with anomalously low (high) sea-ice concentration are associated with proportionally more (less) low-d-excess Baffin Bay moisture at the ice-core site. Multilinear regression models incorporating 2Barrel MSA, d-excess and snow accumulation account for 38–51% of the Baffin Bay sea-ice and temperature variance. The annual temperature model is significantly correlated with temperatures throughout most of Greenland and eastern Arctic Canada due to the strong influence of the North Atlantic Oscillation and Atlantic Multidecadal Oscillation.

APA, Harvard, Vancouver, ISO, and other styles

44

Becoulet, M., G. T. A. Huijsmans, C. Passeron, Y. Q. Liu, T. E. Evans, L. L. Lao, L. Li, et al. "Non-linear MHD modelling of edge localized modes suppression by resonant magnetic perturbations in ITER." Nuclear Fusion 62, no. 6 (April 5, 2022): 066022. http://dx.doi.org/10.1088/1741-4326/ac47af.

Full text

Abstract:

Abstract Edge localized modes (ELMs) suppression by resonant magnetic perturbations (RMPs) was studied with the non-linear magneto-hydro-dynamic (MHD) code JOREK for the ITER H-mode scenarios at 15 MA, 12.5 MA, 10 MA/5.3 T. The main aim of this work was to demonstrate that ELMs can be suppressed by RMPs while the divertor 3D footprints of heat and particle fluxes remain within divertor material limits. The unstable peeling–ballooning modes responsible for ELMs without RMPs were modelled first for each scenario using numerically accessible parameters for ITER. Then the stabilization of ELMs by RMPs was modelled with the same parameters. RMP spectra, optimized by the linear MHD MARS-F code, with main toroidal harmonics N = 2, N = 3, N = 4 have been used as boundary conditions of the computational domain of JOREK, including realistic RMP coils, main plasma, scrape off layer (SOL) divertor and realistic first wall. The model includes all relevant plasma flows: toroidal rotation, two fluid diamagnetic effects and neoclassical poloidal friction. With RMPs, the main toroidal harmonic and the non-linearly coupled harmonics remain dominant at the plasma edge, producing saturated modes and a continuous MHD turbulent transport thereby avoiding ELM crashes in all scenarios considered here. The threshold for ELM suppression was found at a maximum RMP coils current of 45 kAt–60 kAt compared to the coils maximum capability of 90 kAt. In the high beta poloidal steady-state 10 MA/5.3 T scenario, a rotating QH-mode without ELMs was observed even without RMPs. In this scenario with RMPs N = 3, N = 4 at 20 kAt maximum current in RMP coils, similar QH-mode behaviour was observed however with dominant edge harmonic corresponding to the main toroidal number of RMPs. The present MHD modelling was limited in time by few tens of ms after RMPs were switched on until the magnetic energy of the modes saturates. As a consequence the thermal energy was still evolving on this time scale, far from the ITER confinement time scale and hence only the form of 3D footprints on the divertor targets can be indicated within this set-up. Also note, that the divertor physics was missing in this model, so realistic values of fluxes are out of reach in this modelling. However the stationary 3D divertor and particle fluxes could be simply extrapolated from these results to the stationary situation considering that a large power fraction should be radiated in the core and SOL and only about 50 MW power is going to the divertor, which is an arbitrary, but reasonable number used here. The 3D footprints with RMPs show the characteristic splitting with the main RMP toroidal symmetry. The maximum radial extension of the footprints typically was ∼20 cm in inner divertor and ∼40 cm in outer divertor with stationary heat fluxes decreasing further out from the initial strike point from ∼5 MW m−2 to ∼1 MW m−2 assuming a total power in the divertor and walls is 50 MW. The heat fluxes remain within the divertor target and baffle areas, however with rather small margin in the outer divertor which could be an issue for the first wall especially in transient regimes when part of the plasma thermal energy is released due to switching on the RMP coils. This fact should be considered when RMPs are applied with a more favorable application before or soon after the L–H transition, although optimization is required to avoid increasing the L–H power threshold with RMPs.

APA, Harvard, Vancouver, ISO, and other styles

45

Abdullah, Hanida, Aminudin Abu, Pauziah Muhamad, Asnizah Sahekhaini, and Lee Kee Quen. "Analysis of Baffle Effect for Measuring Transmission Loss." Applied Mechanics and Materials 752-753 (April 2015): 1263–68. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.1263.

Full text

Abstract:

Exhaust noise is one of the noise pollution to the environment and it will cause interference that may harm the activity or balance of human. A muffler is designed to minimize transmission caused by exhaust gases. In this paper, the principle of transfer matrix method is used to analyze the transmission loss. The method is used for developed source code programming to predict muffler performance. The result from programming show excellent agreement with the previous established research paper. This programming is applied for baffle effect to determine transmission loss.

APA, Harvard, Vancouver, ISO, and other styles

46

Kinnard, Christophe, Christian M. Zdanowicz, David A. Fisher, and Cameron P. Wake. "Calibration of an ice-core glaciochemical (sea-salt) record with Sea-ice variability in the Canadian Arctic." Annals of Glaciology 44 (2006): 383–90. http://dx.doi.org/10.3189/172756406781811349.

Full text

Abstract:

AbstractCorrelation between glaciochemical time Series from an ice core collected on Devon Ice Cap, Nunavut, Canada, and gridded time Series of Sea-ice concentrations reveals Statistically Significant inverse relationships between Sea-salt concentrations (mainly Na+, Mg2+ and Cl–) in the ice core and Sea-ice cover in Baffin Bay over the period 1980–97. An empirical orthogonal function (Eof) analysis performed on all major ions Shows that the dominant mode of glaciochemical variability (Eof1) represents a Sea-salt Signal, which correlates best with Sea-ice concentration in Baffin Bay. On a Seasonal basis, the Strongest and most Spatially extensive anticorrelations are found in Baffin Bay during the fall, followed by Spring, Summer and winter. These results Support the notion that increased open-water conditions in Baffin Bay during the Stormy Seasons (fall and Spring) promote increased production, transport and deposition of Sea-salt aerosols on Devon Ice Cap. Comparison of ice-core time Series of Eof1, δ18O and melt percentage, with air temperatures recorded in Upernavik, Greenland, Suggests that ice-cover variations in Baffin Bay over the past ∽145 years were dynamically rather than thermodynamically controlled, with periods of Strengthened cyclonic circulation leading to increased open-water conditions, and a greater Sea-salt flux on Devon Ice Cap.

APA, Harvard, Vancouver, ISO, and other styles

47

Feng, D., and D. P. Knight. "Structure and Formation of the Egg Capsule Tendrils in the Dogfish Scyliorhinus canicula." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 343, no. 1305 (February 28, 1994): 285–302. http://dx.doi.org/10.1098/rstb.1994.0026.

Full text

Abstract:

The tendrils of the egg capsule of the dogfish Scyliorhinus canicula appear to act as damped springs which become entagled with one another, attaching the capsule firmly to the seaweed Halidrys siliquosa. The present paper describes the structure of tendrils and their method of formation in a specialized region of the nidamental gland which we have termed the tendril-forming region (TFR). The tendrils provide a unique system for studying the assembly of a complexly ordered collagenous material. Tendrils show primary twisting and then undergo secondary helical coiling. In cross section they have a lamellated, spiral construction. Each lamella appears to consist of a broad and a narrow lamina. Collagen fibril orientation is approximately longitudinal in the broad lamina and approximately circumferential in the narrow one. Fine, longitudinal fluid-filled canaliculi lie between the lamellae and may act as shock absorbers. Spherical granules containing a high concentration of tyrosine residues are present in large numbers in the outermost lamellae and may have rubber-like properties. The collagen is probably heavily cross-linked and gives the tendril high tensile strength. The tendril appears to be formed from the adhesion of successive lamellae which are wrapped round a central core as the forming tendril undergoes counter-clockwise (left-handed) rotation within the TFR. The latter appears to represent a modification of the structure of the simpler capsule wall-forming region (CWFR). A wave of progressive activation of tubular glands of the TFR travelling anteriorly followed by a wave of deactivation in the opposite direction appears to be responsible for the secretion of first the posterior tendril, then the marginal rib of the egg capsule and finally the anterior tendril. Secreted material passes from glandular tubules through secretory ducts to a series of parallel transverse grooves which act as complex extrusion dies to form the lamellae of the tendril. We have gone some way towards describing how the complex three-dimensional organization of the tendril is produced by these dies. Observations suggested the following sequence of events within the extrusion dies: secreted material becomes uniaxially oriented in the secretory duct and is then passed between ciliated plates we have termed `baffle plates'. These separate the material into an anterior flow containing vertically oriented collagen molecules and a thinner posterior flow containing approximately horizontally oriented ones. These two flows then pass through a transverse groove to become respectively the broad and the narrow lamina of a single lamella of the tendril. The lamellae become pleated within the transverse grooves probably by anisotropic shrinkage. The canaliculi appear to be formed by the partial adhesion of the pleated lamellae as they are wound onto the forming tendril by rotation within the TFR. The mechanism of rotation of the forming thread and its subsequent coiling in the posterior oviduct is discussed.

APA, Harvard, Vancouver, ISO, and other styles

48

Li, Shi Wei, and Zheng Fang Wang. "Numerical Controlled Process of Tube Plate and Baffles on Tubular Heat Exchangers." Advanced Materials Research 462 (February 2012): 855–59. http://dx.doi.org/10.4028/www.scientific.net/amr.462.855.

Full text

Abstract:

Tube plate and baffles are all important parts in tubular heat exchangers, drilling holes on them is an important and difficult task for factory. The efficiency of traditional process is low and the error is big. Analyzed the holes’ distributing on six shell side routes exchangers, established mathematics model, compiled numerical controlled program with EIA code, realized numerical controlled process of tube plate and baffles on MITSUBISHI machining center. This improved the quality of equipment and lowered the cost.

APA, Harvard, Vancouver, ISO, and other styles

49

Sharma, Nitin, Trupti Ranjan Mahapatra, Subrata Kumar Panda, and Pankaj Katariya. "Thermo-acoustic analysis of higher-order shear deformable laminated composite sandwich flat panel." Journal of Sandwich Structures & Materials 22, no. 5 (June 27, 2018): 1357–85. http://dx.doi.org/10.1177/1099636218784846.

Full text

Abstract:

The acoustic radiation responses of laminated sandwich baffled flat panels subjected to harmonic loading in an elevated thermal environment are investigated via a novel coupled finite and boundary elements formulation based on the higher-order shear deformation shell theory. The structural stiffness and mass tensors are obtained using competent finite element steps engaging the Hamilton’s principle followed by computation of acoustic responses by resolving the Helmholtz partial differential equation. An in-house MATLAB code is developed based on the present formulation for the computation of all the desired responses. The accuracy and robustness of the present scheme are recognized by the close conformance of the critical buckling temperature, natural frequencies and the sound power level values with the available benchmark solutions alongside the values obtained via a simulation model implemented using commercially available finite element (ANSYS) and boundary element (LMS Virtual.Lab) packages. Subsequently, the present model is employed to solve wide variety of numerical illustrations and the useful inferences related to the influence of elevated temperature, core-to-face thickness ratio, core-to face modular ratio and lay-up scheme on the sound emission characteristics of sandwich composite flat panels are deliberated in detail.

APA, Harvard, Vancouver, ISO, and other styles

50

Andrews, J. T. "Changes in the silt- and clay-size mineralogy of sediments at Ocean Drilling Program site 645B, Baffin Bay." Canadian Journal of Earth Sciences 30, no. 12 (December 1, 1993): 2448–52. http://dx.doi.org/10.1139/e93-211.

Full text

Abstract:

Site 645B, Ocean Drilling Program (ODP) leg 105, was cored in 2010 m water depth off the eastern margin of Baffin Island. A 279 m core was dated as extending back to ca. 2 Ma. Samples of sediment were analyzed for their silt- and clay-size mineralogy using X-ray diffraction techniques. Constrained cluster analysis on these data defined three units, which indicated that significant changes in mineralogies occurred at approximately 75 m below sea floor (bsf) (ca. 0.5 Ma) and 155 m bsf (ca. 1.15 Ma). These boundaries coincide closely with units IA–IB and IB–II as designated in the ODP shipboard reports, and which were based on detrital carbonate and sand contents. Unit II (1.2–2 Ma) is characterized by zero clay-size calcite and high amounts of clay-size smectite and silt-size mica. Unit IB (0.5 – 1.15 Ma) is noteworthy for the first presence of clay-size calcite, high amounts of detrital dolomite, and a peak in clay-size kaolinite. The uppermost unit IA (0–0.5 Ma) is characterized by consistently high values of clay-size dolomite and sand. Compared with sediments on the adjacent eastern Baffin Island shelf and fiords, the sediments at ODP site 645B are enhanced in the amounts of carbonate, smectite, and kaolinite, and depleted in both silt- and clay-size mica and feldspar. This pattern suggests a limited supply of sediment is transported from Baffin Island into Baffin Bay.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Core baffle'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles