scholarly journals Test Results of an Innovative and Modular Sensor Design for Fission Chamber Studies

2020 ◽  
Vol 225 ◽  
pp. 03006
Author(s):  
G. de Izarra ◽  
B. Geslot ◽  
S. Bréaud ◽  
A. Pepino ◽  
J-F. Villard ◽  
...  
Keyword(s):  
Calibration Procedure ◽  
Electrode Gap ◽  
Fission Chamber ◽  
Experimental Database ◽  
Simulation Tools ◽  
Code Validation ◽  
Experimental Validations ◽  
Chamber Studies ◽  
Set Up ◽  
Fission Chambers

Since many years, the Instrumentation, Sensors and Dosimetry laboratory at CEA Cadarache has been working to propose innovative and robust design of fission chambers. In this framework, few simulation tools like Chester or PyFc were developed to make detector prototyping and optimisation possible. Up to now, the code experimental validations are scarce mainly because of the lack of flexibility of regular fission chambers. In order to set up an experimental database for code validation, an innovative modular twin fission chamber, the CFTM, was designed. It allows to set with precision the inter-electrode gap, the filling gas pressure as well as the fissile deposit used. This detector was irradiated in Minerve zero power reactor in order to gather results for code validation. Thanks to a calibration procedure, a bank of experimental results is available for simulation validation.

scholarly journals Characterization and localization of partial-discharge-induced pulses in fission chambers designed for sodium-cooled fast reactors

2018 ◽  
Vol 170 ◽  
pp. 03002
Author(s):  
G. Galli ◽  
H. Hamrita ◽  
C. Jammes ◽  
M.J. Kirkpatrick ◽  
E. Odic ◽  
...  
Keyword(s):  
High Temperature ◽  
Neutron Flux ◽  
Electrical Discharge ◽  
Partial Discharge ◽  
Electrical Signal ◽  
Fast Reactors ◽  
Electrode Gap ◽  
Fission Chamber ◽  
Flux Monitoring ◽  
Fission Chambers

During the operation of the Superphenix and Phenix reactors, an aberrant electrical signal was detected from the fission chambers used for neutron flux monitoring. This signal, thought to be due to partial electrical discharge (PD) is similar to the signal resulting from neutron interactions, and is generated in fission chambers at temperatures above 400 °C. This paper reports work on the characterization and localization of the source of this electrical signal in a High Temperature Fission Chamber (HTFC). The relation between the shape of the PD signal and various parameters (nature and pressure of the chamber filling gas, electrode gap distance, and fission chamber geometry) are first described. Next, experiments designed to identify the location within the chambers where the PD are being generated are presented. After verification and refinement of the results of these localization studies, it should be possible to propose changes to the fission chamber in order to reduce or eliminate the PD signal.

scholarly journals Device for calibration of low pressure gauges development

2002 ◽  
Vol 2 (4) ◽  
pp. 189-195
Author(s):  
Z.D. Nikitovic
Keyword(s):  
High Vacuum ◽  
Low Pressure ◽  
Calibration Procedure ◽  
Vacuum System ◽  
Molecular Collision ◽  
Gas Discharges ◽  
Dry Air ◽  
Vacuum Region ◽  
Set Up ◽  
Made In

Vacuum system set-up is presented and used for calibration of pressure gauges in the region of rough vacuum, from 103 mbar to 10-1 mbar, with dry air. The capacitance manometer is used for the calibration of piezoresistant manometer, oil, mercury and mercury micrometers U manometers. The applicability of the experimental set-up and obtained results for the low pressure gauges calibration in the medium and high vacuum region is approved. It was shown how calibration of some cheaper pressure gauges might be performed and reliable measurements of the pressure may be made in the region that is of interest for atomic and molecular collision physics and low-pressure gas discharges. It was also shown that mentioned calibration procedure could be used for calibration of different U manometer types in order to renormalize older atomic and molecular collision data.

Primary Ionization Density Produced by Charged Fragments in the Working Volume of the Fission Chambers

2021 ◽  
Vol 24 (4) ◽  
pp. 329-337
Author(s):  
A. A. Khrushchinsky ◽  
S. A. Kuten
Keyword(s):  
Spatial Distribution ◽  
Ion Pairs ◽  
Sensitive Volume ◽  
Active Volume ◽  
Fission Chamber ◽  
Ionization Density ◽  
Working Volume ◽  
Fission Chambers ◽  
235U Fission ◽  
Primary Ionization

The question of the spatial distribution of ion pairs created by 235U fission fragments in the active volume of the fission chamber has been studied. The formulas of the spatial distribution of ion pairs in cylindrical fission chambers are proposed, which allows you to evaluate correctly the density of ion pairs in any point in the sensitive volume of the fission chamber

An Analysis of the Effects Causing an Asymmetric Behavior of the Lateral Lubricating Films of External Spur Gear Machines

2021 ◽  
Author(s):  
Kaeul Lim ◽  
Federico Zappaterra ◽  
Swarnava Mukherjee ◽  
Andrea Vacca
Keyword(s):  
Spur Gear ◽  
Common Assumption ◽  
Simulation Tools ◽  
Positive Displacement ◽  
Asymmetric Behavior ◽  
External Gear Pumps ◽  
Pressure Development ◽  
Gear Pumps ◽  
Set Up ◽  
Lateral Gaps

Abstract The torque efficiency and flow efficiency of positive displacement machines for fluid power applications are determined by the behavior of their internal lubricating interfaces. This aspect has motivated the development of tribological simulation tools for the analysis of these interfaces. The level of details these tools can provide allows explaining some counterintuitive aspects that occur in these interfaces. This paper focuses on a significant example, which is the high asymmetric behavior of the lubricating films occurring in pressure compensated external gear pumps. These units are often designed with a symmetric axial balancing compensation system. Notwithstanding, there are differences between the lateral gaps that can be explained only considering the mutual effects of the pressure development in the film and the material deformation. To study this problem, this paper utilizes the tool Multics-HYGESim developed by the authors’ research team. Two analyses are performed: the first one imposing axial symmetry in the behavior of the gap, which is the common assumption discussed in literature; the second one (referred to as “full configuration”), which holds the asymmetric behavior of the gap. An experimental set-up is used to validate the modeling assumptions based on the measurements of the drain leakage and volumetric efficiency. The main paper findings are on the uneven distribution of these leakages, which indicates an asymmetric behavior of the gap films in the unit.

Semi-automatic calibration procedure for the vision-robot interface applied to scale model decoration

Robotica ◽  
1992 ◽  
Vol 10 (4) ◽  
pp. 303-308
Author(s):  
Luis Gonzaga Trabasso ◽  
Cezary Zielinski
Keyword(s):  
Three Dimensional ◽  
Robot Vision ◽  
Work Load ◽  
Calibration Procedure ◽  
Scale Model ◽  
Three Dimensional Objects ◽  
University Of Technology ◽  
Scale Models ◽  
Set Up ◽  
Small Work

SUMMARYA semi-automatic method for calibrating a robot-vision interface is presented. It puts a small work-load on the operator, requires a simple calibration jig and a solution of a very simple system of equations. It has been extensively used in an experimental robotic cell set up at Loughborough University of Technology, where various aspects of the manufacturing and the decoration of scale models are being investigated. As an extension of the calibration procedure, the paper also shows practical solutions for the problem of dealing with three dimensional objects using a single camera.

A study of the light emitted from the initial stages of a spark discharge

1964 ◽  
Vol 278 (1373) ◽  
pp. 168-187 ◽  
Keyword(s):  
Threshold Voltage ◽  
High Speed ◽  
Homogeneous Field ◽  
Electrode Gap ◽  
Diffuse Discharge ◽  
Glow Discharges ◽  
Field Electrode ◽  
Atomic Lines ◽  
Chamber Studies ◽  
Spark Channel

Measurements have been made, by means of submicrosecond impulses, on the threshold voltage at which the first visible discharge occurs in a homogeneous field electrode gap. Various gases have been used at different values of gap and gas pressure. In most gases there is some indication of a change in the form of the initial discharge as the gap is varied. At a certain value of electrode gap, depending upon the impulse length and gap pressure, there is a change in slope of the threshold voltage-gap curve. Above this point the discharges are generally filamentary whereas at smaller gaps they are broad and diffuse. In air, nitrogen and oxygen the filamentary discharges are often constricted at a point in the gap. The position of this constriction depends on the impulse and gap length. It is suggested that the filamentary discharges correspond to a streamer type of discharge and are similar to the ones observed in the previous cloud chamber studies. The broad diffuse discharge which occurs at smaller gaps is probably the Townsend type of discharge In argon and hydrogen the evidence for the existence of two breakdown mechanisms is not very strong. High-speed streak photography has revealed that the filamentary glow discharges in air appear to grow towards the constriction. A spark channel then begins to form at the constriction and grows towards the electrodes. Spectroscopic examination of the various types of discharge shows the prominent second positive N 2 bands for discharges in air and nitrogen but with a continuum, N + 2 bands and atomic lines in the constriction. An estimate of the peak electron energy has been made for various discharges in air and nitrogen and found to be about 14eV.

scholarly journals Water vapor observations up to the lower stratosphere through the Raman lidar during the MAïdo LIdar Calibration Campaign

2014 ◽  
Vol 7 (10) ◽  
pp. 10361-10422
Author(s):  
D. Dionisi ◽  
P. Keckhut ◽  
Y. Courcoux ◽  
A. Hauchecorne ◽  
J. Porteneuve ◽  
...  
Keyword(s):  
Water Vapor ◽  
Calibration Procedure ◽  
Relative Difference ◽  
Lamp Method ◽  
Control Procedure ◽  
Significant Difference ◽  
The Mean ◽  
Set Up ◽  
Lidar Calibration ◽  
Good Agreement

Abstract. A new lidar system devoted to tropospheric and lower stratospheric water vapor measurements has been installed at the Maïdo altitude station facility of La Reunion Island, in the southern subtropics. The main objectives of the MAïdo LIdar Calibration Campaign (MALICCA), performed in April 2013, were to validate the system, to set up a calibration methodology, to compare the acquired water profiles with radiosonde measurements and to evaluate its performances and capabilities with a particular focus on the UTLS measurements. Varying the characteristics of the transmitter and the receiver components, different system configuration scenarios were tested and possible parasite signals (fluorescent contamination, rejection) were investigated. A hybrid calibration methodology has been set up and validated to insure optimal lidar calibration stability with time. In particular, the receiver transmittance is monitored through the calibration lamp method that, at the moment, can detect transmittance variations greater than 10–15%. Calibration coefficients are then calculated through the hourly values of IWV provided by the co-located GPS. The comparison between the constants derived by GPS and Vaisala RS92 radiosondes launched at Maïdo during MALICCA, points out an acceptable agreement in terms of accuracy of the mean calibration value (with a difference of approximately 2–3%), but a significant difference in terms of variability (14 vs. 7–9%, for GPS and RS92 calibration procedures, respectively). We obtained a relatively good agreement between the lidar measurements and 15 co-located and simultaneous RS92 radiosondes. A relative difference below 10% is measured in low and middle troposphere (2–10 km). The upper troposphere (up to 15 km) is characterized by a larger spread (approximately 20%), because of the increasing distance between the two sensors. To measure water vapor in the UTLS region, nighttime and monthly water vapor profiles are presented and compared. The good agreement between the lidar monthly profile and the mean WVMR profile measured by satellite MLS has been used as a quality control procedure of the lidar product, attesting the absence of significant wet biases and validating the calibration procedure. Thanks to its performance and location, the MAIDO H2O lidar is devoted to become a reference instrument in the southern subtropics, allowing to insure the long-term survey of the vertical distribution of water vapor, and to document scientific themes such as stratosphere–troposphere exchange, tropospheric dynamics in the subtropics, links between cirrus clouds and water vapor.

Stress Calibration Methodology of Stator Blades Using Experimental SAFE Diagram

2018 ◽  
Author(s):  
Jérôme Ligot ◽  
Sébastien Hoffait ◽  
Jean de Cazenove ◽  
Frédéric Vallino ◽  
Jean-Claude Golinval
Keyword(s):  
Calibration Procedure ◽  
The Novel ◽  
Strain Gages ◽  
Post Processing ◽  
Nodal Diameter ◽  
Strain Measurements ◽  
Optimal Excitation ◽  
Set Up ◽  
Processing Techniques ◽  
The Impact

This paper introduces an improvement of the stress calibration methodology of stator blades to consider a nodal diameter of interest of the structure. The proposed calibration procedure and the search for optimal excitation set-up are detailed. To this purpose, the following points are addressed. Experimental modal analyses are performed using both accelerometers and strain gages. Post-processing techniques are developed to determine the nodal diameters of the identified modes. SAFE (Singh’s Advanced Frequency Evaluation) diagrams are computed from the experimental data and compared with the diagrams obtained numerically by finite elements computations. Multiple excitations are used to appropriate the targeted modes. A comparative study of different shaker types, of the number of excitation points and of their location is performed. Calibration is achieved by comparing strain measurements taken on one gage installed on the engine and velocities measured using laser vibrometers. It allows reducing the impact of the instrumentation on the modal content. The calibration factors obtained by the novel proposed procedure are compared to the ones given by the currently used methodology.

scholarly journals A Survey on Daylighting Education in Italian Universities. Knowledge of Standards, Metrics and Simulation Tools

2021 ◽  
Vol 8 (1) ◽  
pp. 36-49
Author(s):  
V. R. M. Lo Verso ◽  
◽  
F. Giuliani ◽  
F. Caffaro ◽  
F. Basile ◽  
...  
Keyword(s):  
Sustainable Buildings ◽  
Simulation Tools ◽  
Low Level ◽  
Level Of Knowledge ◽  
European Students ◽  
Set Up ◽  
New Generation ◽  
Italian Architecture

Daylighting is a strategic topic to achieve sustainable buildings, so it is more and more imperative that it is implemented in architecture curricula to prepare a new generation of daylighting-oriented practitioners. In this frame, the DAYKE project (Daylight Knowledge in Europe) was set up to explore the level of knowledge about daylighting among European professionals and students. DAYKE-Europe was replicated as DAYKE-Italy to study the knowledge of daylight standards, metrics and software among Italian architecture students, and to compare it to that observed within DAYKE-Europe. A sample of 542 questionnaires were collected in five universities. Primary outcomes were: (i) a general low level of knowledge on daylighting was observed; the most cited metrics were the average daylight factor and the geometrical window-to-floor ratio, while climate-based daylight metrics were rarely mentioned; (ii) master science M.Sc. students reported more knowledge on daylight metrics and regulations than bachelor B.Sc. students, while the implementation of daylight metrics and strategies in projects was mainly deficient among B.Sc. students; (iii) compared to European students (DAYKE-Europe), Italian students showed a higher knowledge of daylight metrics and software (especially as for M.Sc. students), while the opposite was observed for standards, regulations and protocols. Based on the results, a reconsideration of daylight education in architecture curricula is recommended.

Sign in / Sign up

Export Citation Format

Share Document