Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 59
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

In this paper, we present an experimental setup developed for the calibration of dynamic force transducers which is based on the drop mass method. The traceability to SI units is realized through well-known mass characteristics and a reference shock accelerometer attached to that mass. Two approaches are proposed to analyse dynamic force employing a drop mass system. One approach depends on the inertial force of a falling mass while the other deals with the work-energy principle. Results of both approaches are then compared to the response of a statically calibrated force transducer. It is shown that the obtained maximum relative deviations between the response of force transducer and the first approach results are 1% while those of the second approach are 2%.
Go to article

Bibliography

[1] Fujii, Y., Isobe, D., Saito, S., Fujimoto, H., & Miki, Y. (2000). A method for determining the impact force in crash testing. Mechanical Systems and Signal Processing, 14(6), 959–965. https://doi.org/10.1006/mssp.1999.1272
[2] Fujii, Y. (2003). A method for calibrating force transducers against oscillation force. Measurement Science and Technology, 14(8), 1259–1264. https://doi.org/10.1088/0957-0233/14/8/310
[3] Hjelmgren, J. (2002). Dynamic Measurement of Force – A Literature Survey (SP Report 2002:34). SP Swedish National Testing and Research Institute SP Measurement Technology.
[4] Jun, Y., Yiqing, C., Xuan, H., & Xiao, Y. (2017). Impulse force calibration with dropped weight and laser vibrometer. IMEKO 23rd TC3, 13th TC5 and 4th TC22 International Conference, Finland, 19. https://www.imeko.org/publications/tc3-2017/IMEKO-TC3-2017-030.pdf
[5] Kobusch, M., Link, A., Buss, A., & Bruns, T. (2007). Comparison of shock and sine force calibration methods. IMEKO 20th TC3, 3rd TC16 and 1st TC22 International Conference, Maxico. https://www.imeko.org/publications/tc3-2007/IMEKO-TC3-2007-007u.pdf
[6] Satria, E., Takita, A., Nasbey, H., Prayogi, I. A., Hendro, H., Djamal, M., & Fujii, Y. (2018). New technique for dynamic calibration of a force transducer using a drop ball tester. Measurement Science and Technology, 29(12). https://doi.org/10.1088/1361-6501/aaeb71
[7] Schlegel, C., Kieckenap, G., Glöckner, B., Buß, A., & Kumme, R. (2012). Traceable periodic force calibration. Metrologia, 49(3), 224–235. https://doi.org/10.1088/0026-1394/49/3/224
[8] Sivaselvan, M. V., Reinhorn, A. M., Shao, X., & Weinreber, S. (2008). Dynamic force control with hydraulic actuators using added compliance and displacement compensation. Earthquake Engineering and Structural Dynamics, 37(15), 1785–1800. https://doi.org/10.1002/eqe.837
[9] Stanford, A. L., & Tanner, J. M. (1985). Work, Power, and Energy. In Physics for Students of Science and Engineering (pp. 109–144). Elsevier Inc. https://doi.org/10.1016/b978-0-12-663380-1.50008-2
[10] Vlajic, N., & Chijioke, A. (2017). Traceable calibration and demonstration of a portable dynamic force transfer standard. Metrologia, 54(4), S83–S98. https://doi.org/10.1088/1681-7575/aa75da
[11] Yang, Y., Zhao, Y., & Kang, D. (2016). Integration on acceleration signals by adjusting with envelopes. Journal of Measurements in Engineering, 4(2), 117–121. https://www.jvejournals.com/ article/16965/pdf
[12] Zhang, L., & Kumme, R. (2003). Investigation of interferometric methods for dynamic force measurement. In XVII IMEKO World Congress, Metrology in the 3rd Millennium, Croatia, 315–318.
[13] Zhang, L.,Wang, Y., & Zhang, L. (2010). Investigation of calibrating force transducer using sinusoidal force. AIP Conference Proceedings, 1253, 395–401. https://doi.org/10.1063/1.3455481
Go to article

Authors and Affiliations

Shaker A. Gelany
1
Gouda M. Mahmoud
1

  1. National Institute of Standards (NIS), Tersa St, El-Haram, PO Box 136, Code 12211, Giza, Egypt
Download PDF Download RIS Download Bibtex

Abstract

Inertial navigation is a device, which estimates its position, based on sensing external conditions (such as acceleration or angular velocity). It is widely used in variuos applications. Its presence in a drone vehicle for example, allows flight stabilization, by position estimation and feedback-based regulation algorithm execution. A smartphone makes a use of inertial navigation by detecting movement and flipping screen orientation. It is a ubiquitous part of many devices of everyday use, but before using filters and algorithms allowing to calculate the position, a calibration must first be applied to the device. This paper focuses on a separate calibration of each of the sensors - an accelerometer, gyroscope and magnetometer. The further step requires a cross–sensor calibration, and the third step is implementation of data filtration algotithm.
Go to article

Authors and Affiliations

Sławomir Niespodziany
Download PDF Download RIS Download Bibtex

Abstract

Hydrological modelling uses modern computational methods to simulate local and regional water circulation systems. How does this work, and what benefits does it bring?

Go to article

Authors and Affiliations

Monika Okońska
Download PDF Download RIS Download Bibtex

Abstract

The paper deals with the design of equipment for verification and calibration of axle and crane weighing instruments. In its introduction, it discusses the basic concepts of axle and crane weighing instruments, their calibration, and verification. The paper briefly describes the original technical design solution used in the calibration and verification of these weighing instruments. Subsequently, the article describes the legislative, technical and functional requirements for metrological equipment being developed. The paper presents two design solutions for handling calibration weights. In both solutions, the construction and individual functional parts of the equipment are described. Both of these solutions were designed and tested in practical measurements in the Laboratory for Testing ofWeighing Instruments of the Slovak Legal Metrology n.o. Finally, the paper presents the results of the development of a new measuring system at the University of Žilina.
Go to article

Authors and Affiliations

Tomas Gajdosik
1
Lubos Kucera
1
Igor Gajdac
1
Anton Fric
2
Jaromir Markovic
2

  1. University of Žilina, Faculty of Mechanical Engineering, Department of Design and Mechanical Elements, Univerzitná 8215/1, 010 26 Žilina, Slovakia
  2. Slovak Legal Metrology, Hviezdoslavova 1124/31, 974 01 Banská Bystrica, Slovakia
Download PDF Download RIS Download Bibtex

Abstract

The Centro de Desarrollo Tecnológico del Gas developed a static expansion system to enable the calibration of medium and high vacuum pressure gauges in Colombia. The system can generate pressures between 0.1 Pa and 100 kPa. The characterization tests included the evaluation of pressure stability and desorption rate, a trueness test, and the analysis of the uncertainty budget of the calibration result. The pressure stability test was successfully completed and showed the positive effect of baking on the final pressure in the system. The trueness test allowed concluding that the calibration results with the system are comparable with those obtained with a reference meter traceable to a national metrology institute. The uncertainty budget analysis indicated the dominance of the pressure of the unit under calibration and of the initial pressure in the small tank in different pressure ranges on the uncertainty of the result. A comparison with a Monte Carlo simulation led to the conclusion that in this situation, the GUM (Guide to the Expression of Uncertainty in Measurement) method is not ideal for estimating the uncertainty of the results.
Go to article

Bibliography

[1] Khan,W., Hong, H. H., Satar, T., Ahmed, M., Khan, Z. A.,& Khan, M. Z. (2016). The KRISS primary vacuum gauge calibration standards:Areview. Journal of the Vacuum Society of Japan, 59(8), 222–235.
[2] Astrua, M., Mari, D., & Pasqualin, S. (2019). Improvement of INRiM static expansion system as vacuum primary standard between 10(-4) Pa and 1000 Pa. 19th International Congress of Metrology, 27007. https://doi.org/10.1051/metrology/201927007
[3] Semwal, P., Khan, Z., Dhanani, K. R., Pathan, F. S., George, S., Raval, D. C., Thankey, P. L., Paravastu, Y., & Himabindu, M. (2012). Spinning rotor gauge based vacuum gauge calibration system at the Institute for Plasma Research. Journal of Physics: Conference Series, 390, 012027. https://doi.org/10.1088/1742-6596/390/1/012027
[4] Bergoglio, M., & Calcatelli, A. (2004). Uncertainty evaluation of the IMGC-CNR static expansion system. Metrologia, 41, 278–284. https://doi.org/10.1088/0026-1394/41/4/009
[5] Greenwood, J. C. (2006). Simulation of the operation and characteristics of static expansion pressure standards. Vacuum, 80, 548–553. https://doi.org/10.1016/j.vacuum.2005.09.003
[6] Soriano Cardona, B., Torres Guzmán, J., & Santander Romero, L. (2001). Sistema de referencia nacional para la medición de vacío. Simposio de Metrología CENAM 2001, México.
[7] Bergoglio, M., Calcatelli, A., Marzola, L., & Rumiano, G. (1988). Primary pressure measurements down to 10(-6) Pa. Vacuum, 38(8–10), 887–891. https://doi.org/10.1016/0042-207X(88)90486-1
[8] Fedchak, J. A., Abbott, P. J., & Hendricks, J. H. (2018). Review Article: Recommended practice for calibrating vacuum gauges of the ionization type. Journal of Vacuum Science & Technology A, 36, 030802. https://doi.org/10.1116/1.5025060
[9] Torres Guzmán, J. C., Santander, L. A., & Jousten, K. (2005). Realization of the medium and high vacuum primary standard inCENAM,Mexico.Metrologia, 42(6), S157–S160. https://doi.org/10.1088/0026-1394/42/6/S01
[10] Jousten, K., Röhl, P., & Aranda Contreras, V. (1999). Volume ratio determination in static expansion systems by means of a spinning rotor gauge. Vacuum, 52(4), 491–499. https://doi.org/10.1016/S0042-207X(98)00337-6
[11] Herranz, D., Ruiz, S., & Medina, N. (2009). Volume ratio determination in static expansion systems by means of two pressure balances. XIX IMEKO World Congress, Fundamental and Applied Metrology, Portugal. https://www.imeko2009.it.pt/Papers/FP_280.pdf
[12] Phanakulwijit, S.,&Pitakarnnop, J. (2019). Establishment of Thailand’s national primary vacuum standard by a static expansion method. Journal of Physics: Conference Series, 1380, 012003. https://doi.org/10.1088/1742-6596/1380/1/012003
[13] Jitschin, W. (2002). High-accuracy calibration in the vacuum range 0.3 Pa to 4000 Pa using the primary standard of static gas expansion. Metrologia, 39(3), 249–261. https://doi.org/10.1088/0026-1394/39/3/2
[14] Kangi, R., Ongun, B., & Elkatmis, A. (2004). The new UME primary standard for pressure generation in the range from 9 × 10 -4 Pa to 103 Pa. Metrologia, 41(4), 251–256. https://doi.org/10.1088/ 0026-1394/41/4/005
[15] International Organization for Standardization. (2011). Vacuum gauges – Calibration by direct comparison with a reference gauge ISO Standard No. 3567:2011. https://www.iso.org/standard/59372.html
[16] Antsukova, A. I., Gorobei, V. N., Liubomirov, A. B., Pimenova, A. A.,&Chernyshenko, A. A. (2019). Calibration of measuring instruments of low absolute pressures. IOP Conference Series: Journal of Physics: Conference Series, 1313, 012002. https://doi.org/10.1088/1742-6596/1313/1/012002
[17] Ruiz González, S. (2011). Desarrollo de un nuevo patrón nacional de presión. Desde la columna de mercurio a patrones primarios de vacío [Doctoral dissertation, Universidad de Valladolid]. UVaDOC Repositorio Documental de la Universidad de Valladolid. https://doi.org/10.35376/10324/830
[18] Joint Committee for Guides in Metrology. (2008). Evaluation of measurement data – Guide to the expression of uncertainty in measurement (JCGM 100:2008). http://www.bipm.org/utils/common/ documents/jcgm/JCGM_100_2008_E.pdf
[19] Joint Committee for Guides in Metrology. (2008). Evaluation of measurement data – Supplement 1 to the “Guide to the expression of uncertainty in measurement” – Propagation of distributions using a Monte Carlo method (JCGM 101:2008). https://www.bipm.org/documents/20126/2071204/ JCGM_101_2008_E.pdf

Go to article

Authors and Affiliations

Jonathan Javier Duarte Franco
1
Carlos Mauricio Villamizar Mora
2
Carlos Eduardo García Sánchez
1

  1. Corporación Centro de Desarrollo Tecnológico del Gas, Grupo de Investigación en Fluidos y Energía, Carrera 23# 106-08, ZIP 680004, Bucaramanga, Colombia
  2. Universidad Industrial de Santander, Escuela de Ingeniería Mecánica, Grupo de Investigación en Energía y MedioAmbiente, Carrera 27 calle 9, ZIP 680002, Bucaramanga, Colombia
Download PDF Download RIS Download Bibtex

Abstract

This paper introduces a new comprehensive procedure for both geometric and colour calibration of structured light system. In order to perform both geometric and colour calibration procedure, a new calibration artifact is proposed. The intrinsic and extrinsic parameters of projector and camera are estimated by using an extended pinhole camera model with a tangential and radial distortion. Camera image plane coordinates are obtained by extracting features from images of a calibration artifact. Projector image plane coordinates are calculated on the basis of continuous phase maps obtained from a fringe pattern phase reconstruction procedure. In order to stereo calibrate camera-projector system, pairs of corresponding image plane points are calculated with subpixel accuracy. In addition, one of three pattern views is used in colour calibration. RGB values of a colour field pattern detected by camera and their reference values are compared. This comparison leads to derivation of a colour transformation matrix. The performance of the proposed method is tested by measuring plane, sphere and distance reference. Also 360 degrees complex object 3D model from a set of measurements is obtained. Residual mean errors for all tests performed are calculated.

Go to article

Authors and Affiliations

K. Szelag
G. Maczkowski
R. Gierwialo
A. Gebarska
R. Sitnik
Download PDF Download RIS Download Bibtex

Abstract

The objective of the submitted paper is to analyze the influence of the load on the calibration of micro-hardness and hardness testers. The results were validated by Measurement Systems Analysis (MSA), Analysis of Variance (ANOVA) and Z-score. The relationship between the load and micro-hardness in calibration of micro-hardness testers cannot be explained by Kick's Law (Meyer's index "n" is different from 2). The conditions of Kick's Law are satisfied at macro-hardness calibration, the values of "n" are close to 2, regardless of the applied load. The apparent micro-hardness increases with the increase of the load up to 30 g; the reverse indentation size effect (ISE) behavior is typical for this interval of the loads. The influence of the load on the measured micro-hardness is statistically significant for majority of calibrations.

Go to article

Authors and Affiliations

Jozef Petrík
Pavol Palfy
Download PDF Download RIS Download Bibtex

Abstract

The paper discusses the problems of the calibration process of very close range semi-metric digital cameras. Using such cameras for precise measurement of small objects, the photographs have to be taken at a very large scale, ranging from 1 :20 to 1:50. To ensure the submillimetre accuracy of the photogrammetric measurement, the specific calibration tests and procedures for determination of the interior orientation parameters, including the coefficients for image systematic errors, must be applied. The results of two calibration approaches, based on 3D and 2D calibration tests, have been presented in the paper. The experiment is a part of the research project concerning the numerical modelling of small 3D fragments of the broken archaeological items for reconstruction of the context of the archaeological monument.
Go to article

Authors and Affiliations

Aleksandra Bujakiewicz
Michał Kowalczyk
Piotr Podlasiak
Dorota Zawieska
Download PDF Download RIS Download Bibtex

Abstract

The paper deals with calibration of the simulation models of hydraulic part of an irrigation project. Calibrated simulation model can be used in design, reconstruction, enlargement or maintenance of the pressurized irrigation systems. Computer model of the water distribution system is a valuable tool which can assist engineers and planners in analyzing the hydraulic performance of water delivery systems. Calibration of the water distribution model consists in comparison of pressures and flows predicted with observed pressures and flows for known operating conditions (i.e., pump operation, tank levels, pressure-reducing valve settings), and adjustment of the input data for the model to improve agreement between observed and predicted values. In practice, given a set or sets of measured state variables, engineers apply trial and error techniques with their judgment to vary the parameters and accomplish this task. Trial and error techniques are tedious do not guarantee reasonable results. The paper introduces the methodology of determination of calibrated parameters automatically. Described methodology of calibration is based on optimizing procedures using the harmony search approach.

Go to article

Authors and Affiliations

Milan Čistý
Download PDF Download RIS Download Bibtex

Abstract

Capacitive leakage and adjacent interference are the main influence sources of the measuring error in the traditional series step-up method. To solve the two problems, a new algorithm was proposed in this study based on a three-ports network. Considering the two influences, it has been proved that response of this three-ports network still has characteristics of linear superposition with this new algorithm. In this threeport network, the auxiliary series voltage transformers use a two-stage structure that can further decrease measurement uncertainty. The measurement uncertainty of this proposed method at 500/√3 kV is 6.8 ppm for ratio error and 7 μrad for phase displacement ( k = 2). This new method has also been verified by comparing its results with measurement results of the PTB in Germany over the same 110/√3 kV standard voltage transformer. According to test results, the error between the two methods was less than 2.7 ppm for ratio error and 2.9 μrad for phase displacement.
Go to article

Authors and Affiliations

Hao Liu
1 2
Lixue Chen
1
Xue Wang
2
Teng Yao
2
Xiong Gu
2

  1. State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, No. 1037 Luoyu Road Hongshan District, Wuhan, China
  2. China Electric Power Research Institute, Wuhan, China
Download PDF Download RIS Download Bibtex

Abstract

The current research work presents an investigation into use of the fitting coefficients resulting from the cubic curve fitting of the torque transducer calibration results in one direction to calculate the actual torque in the other torque direction with two methods: one is direct substitution with the nominal torque which gives a propagated linear relative interpolation error and the other is changing the sign of the second coefficient in the cubic function when using in the other torque direction. This proposed modification improves the absolute relative interpolation error by 5 to 16 times in the clockwise and counterclockwise directions based on the torque transducer’s classification.
Go to article

Authors and Affiliations

K.M. Khaled
1
Seif M. Osman
1

  1. National Institute of Standards (NIS), Force and Material Metrology Department, Tersa st., 11221 Giza, Egypt
Download PDF Download RIS Download Bibtex

Abstract

This paper presents and compares microphone calibration methods for the simultaneous calibration of small electret microphones in a wave guide. The microphones are simultaneously calibrated to a reference microphone both in amplitude and phase. The calibration procedure is formulated on the basis of the damped plane wave propagation equation, from which the acoustics field along the wave guide is predicted, using several reference measurements. Different calibration models are presented and the methods were found to be sensitive to the formulation, as well as to the number of free parameters used during the reconstruction of the wave-field. The wave guide model based on five free parameters was found to be the preferred method for this type of calibration procedure.

Go to article

Authors and Affiliations

Péter Tóth
Christophe Schram
Download PDF Download RIS Download Bibtex

Abstract

The aim of this paper is two-fold. First, some basic notions on acoustic field intensity and its measurement are shortly recalled. Then, the equipment and the measurement procedure used in the sound intensity in the performed research study are described. The second goal is to present details of the design of the engineered 3D intensity probe, as well as the algorithms developed and applied for that purpose. Results of the intensity probe measurements along with the calibration procedure are then contained and discussed. Comparison between the engineered and the reference commercial probe confirms that the designed construction is applicable to the sound field intensity measurements with a sufficient effectiveness.

Go to article

Authors and Affiliations

Bożena Kostek
Andrzej Czyżewski
Józef Kotus
Download PDF Download RIS Download Bibtex

Abstract

Solar radiation (Rs) is an essential input for estimating reference crop evapotranspiration, ETo. An accurate estimate of ETo is the first step involved in determining water demand of field crops. The objective of this study was to assess the ac-curacy of fifteen empirical solar radiations (Rs) models and determine its effects on ETo estimates for three sites in humid tropical environment (Abakaliki, Nsukka, and Awka). Meteorological data from the archives of NASA (from 1983 to 2005) was used to derive empirical constants (calibration) for the different models at each location while data from 2006 to 2015 was used for validation. The results showed an overall improvement when comparing measured Rs with Rs determined us-ing original constants and Rs using the new constants. After calibration, the Swartman–Ogunlade (R2 = 0.97) and Chen 2 models (RMSE = 0.665 MJ∙m–2∙day–1) performed best while Chen 1 (R2 = 0.66) and Bristow–Campbell models (RMSE = 1.58 MJ∙m–2∙day–1) performed least in estimating Rs in Abakaliki. At the Nsukka station, Swartman–Ogunlade (R2 = 0.96) and Adeala models (RMSE = 0.785 MJ∙m–2∙day–1) performed best while Hargreaves–Samani (R2 = 0.64) and Chen 1 mod-els (RMSE = 1.96 MJ∙m–2∙day–1) performed least in estimating Rs. Chen 2 (R2 = 0.98) and Swartman–Ogunlade models (RMSE = 0.43 MJ∙m–2∙day–1) performed best while Hargreaves–Samani (R2 = 0.68) and Chen 1 models (RMSE = 1.64 MJ∙m–2∙day–1) performed least in estimating Rs in Awka. For estimating ETo, Adeala (R2 =0.98) and Swartman–Ogunlade models (RMSE = 0.064 MJ∙m–2∙day–1) performed best at the Awka station and Swartman–Ogunlade (R2 = 0.98) and Chen 2 models (RMSE = 0.43 MJ∙m–2∙day–1) performed best at Abakaliki while Angstrom–Prescott–Page (R2 = 0.96) and El-Sebaii models (RMSE = 0.0908 mm∙day–1) performed best at the Nsukka station.

Go to article

Authors and Affiliations

Emeka Ndulue
Ikenna Onyekwelu
Kingsley Nnaemeka Ogbu
Vintus Ogwo
Download PDF Download RIS Download Bibtex

Abstract

Direct sensor-to-microcontroller is a simple approach for direct interface of passive modulating sensors to a microcontroller without any active components in between the sensor and the microcontroller and without an analog to digital converter. The metrological performances of such interface circuits are limited by certain microcontroller parameters which are predetermined by the manufacturing technology. These limitations can be improved by specific hardware-related techniques and can improve the accuracy, speed and resolution of the measurements. Such hardware solutions as well as proper selection of the electrical components are addressed in this paper. It has been shown that employment of only a few MOSFET transistors can reduce the maximal relative error of single point calibration more than fifteen times and can increase the measuring speed around 30 % in all calibration techniques in the measurement range of PT1000 resistive temperature sensors. Moreover, the effective number of resolution bits increases by more than 1.3 bits when using an external comparator.

Go to article

Authors and Affiliations

Zivko Kokolanski
Cvetan Gavrovski
Vladimir Dimcev
Mario Makraduli
Download PDF Download RIS Download Bibtex

Abstract

The tendencies of modern industry are to increase the quality of manufactured products, simultaneously decreasing production time and cost. The hybrid system combines advantages of the high accuracy of contact CMM and the high measurement speed of non-contact structured light optical techniques. The article describes elements of a developed system together with the steps of the measurement process of the hybrid system, with emphasis on segmentation algorithms. Additionally, accuracy determination of such a system realized with the help of a specially designed ball-plate measurement standard is presented.

Go to article

Authors and Affiliations

Jerzy Sładek
Robert Sitnik
Magdalena Kupiec
Paweł Błaszczyk
Download PDF Download RIS Download Bibtex

Abstract

In this study, a procedure for optimal selection of measurement points using the D-optimality criterion to find the best calibration curves of measurement sensors is proposed. The coefficients of calibration curve are evaluated by applying the classical Least Squares Method (LSM). As an example, the problem of optimal selection for standard pressure setters when calibrating a differential pressure sensor is solved. The values obtained from the D-optimum measurement points for calibration of the differential pressure sensor are compared with those from actual experiments. Comparison of the calibration errors corresponding to the D-optimal, A-optimal and Equidistant calibration curves is done.

Go to article

Authors and Affiliations

Chingiz Hajiyev
Download PDF Download RIS Download Bibtex

Abstract

Solar-blind ultraviolet cameras with image intensifier with CMOS detector typically use various count methodologies to measure the optical energy of an electrical corona. However, these count methodologies are non-radiometric without considering parameters such as distance, focus-, zoom-, and gain setting of a camera. An algorithm which considers the calibration and radiometric measurement of optical energy for the slow frame rate intensifier type cameras is presented. Furthermore, it is shown how these calibration data together with the flowcharts are used for the conversion from raw measured data to radiometric energy values.
Go to article

Bibliography

  1. Gubanski, S., Dernfalk, A., Andersson, J. & Hillborg, H. Diagnostic methods for outdoor polymeric insulators. IEEE Trans. Dielectr. Electr. Insul. 14, 1065–1080 (2007). https://doi.org/10.1109/TDEI.2007.4339466
  2. Lindner, M., Elstein, S., Lindner, P., Topaz, J. M. & Phillips, A. J. Daylight corona discharge imager. in 1999 11th International Symposium on High Voltage Engineering 349–352 (London, 1999). https://doi.org/10.1049/cp:19990864
  3. Bass, M. et al. Handbook of Optics, Volume II: Design, Fabrication and Testing, Sources and Detectors, Radiometry and Photometry. (McGraw-Hill, Inc., 2009).
  4. Coetzer, C. et al. Status quo and aspects to consider with ultraviolet optical versus high voltage energy relation investigations. in 5th Conference on Sensors, MEMS, and Electro-Optic Systems 1104317 (Skukuza, South Africa, 2019). https://doi.org/10.1117/12.2501251
  5. Maistry, N., Schutz, R. A. & Cox, E. The quantification of corona discharges on high voltage electrical equipment in the uv spectrum using a corona camera. in 2018 International Conference on Diagnostics in Electrical Engineering (Diagnostika) 1–4 (Pisen, Czech Republic, 2018). https://doi.org/10.1109/DIAGNOSTIKA.2018.8526024
  6. Dai, R., Lu, F. & Wang, S. Relation of composite insulator surface discharge ultraviolet signal with electrical pulse signal. in 2011 International Conference on Electrical and Control Engineering 282–285 (Wuhan, China, 2011). https://doi.org/10.1109/ICECENG.2011.6056830
  7. Wang, S., Lv, F. & Liu, Y. Estimation of discharge magnitude of composite insulator surface corona discharge based on ultraviolet imaging method. IEEE Trans. Dielectr. Electr. Insul. 21, 1697–1704 (2014). https://doi.org/10.1109/TDEI.2014.004358
  8. Suhling, K., Airey, R. W. & Morgan, B. L. Optimisation of centroiding algorithms for photon event counting imaging. Nucl. Instrum. Methods Phys. Res. B 437, 393–418 (1999).  https://doi.org/10.1016/S0168-9002(99)00770-6
  9. Boksenberg, A., Coleman, C., Fordham, J. & Shortridge, K. Interpolative centroiding in CCD-based image photon counting systems. Adv. Electron. Electron. Phys. 64, 33–47 (1986). https://doi.org/10.1016/S0065-2539(08)61601-7
  10. Fordham, J., Moorhead, C. & Galbraith, R. Dynamic-range limitations of intensified CCD photon-counting detectors. Mon. Notices Royal Astron. Soc. 312, 83–88 (2000). https://doi.org/10.1046/j.1365-8711.2000.03155.x
  11. Coetzer, C. J. & Leuschner, F. W. The influence of a camera's spectral transfer function used for observing high voltage corona on insulators. IEEE Trans. Dielectr. Electr. Insul. 23, 1753–1759 (2016). https://doi.org/10.1109/TDEI.2016.005021
  12. Hamamatsu Photonics, K. K. Photomultiplier tubes: Basics and applications. Edition 3a. https://www.hamamatsu.com/content/dam/hamamatsu-photonics/sites/documents/99_SALES_LIBRARY/etd/PMT_handbook_v3aE.pdf (2007).
  13. Coetzer, C., Becker, T., West, N. & Leuschner, W. Investigating an alternate detector for solar-blind ultraviolet cameras for high-voltage inspection. in 2021 Southern African Universities Power Engineering Conference/Robotics and Mechatronics/Pattern Recognition Association of South Africa (SAUPEC/RobMech/PRASA) 1–6 (2021). https://doi.org/10.1109/SAUPEC/RobMech/PRASA52254.2021.9377216
  14. IS/IEC 60270:2000 Indian Standard, High Voltage Test Techniques-Partial Discharge Measurements. (International Electrotechnical Commission, 2000).
  15. Tang, J., Luo, X. & Pan, C. Relationship between PD magnitude distribution and pulse burst for positive coronas. IET Sci. Meas. Technol. 12, 970–976 (2018). https://doi.org/10.1049/iet-smt.2018.5039
  16. Willers, C. J. Electro-Optical System Analysis and Design: A Radiometry Perspective. (Society of Photo-Optical Instrumentation Engineers, 2013). https://doi.org/10.1117/3.1001964
  17. Wyatt, C. Radiometric Calibration: Theory and Methods, (Elsevier, 2012).
  18. Coetzer, C., Groenewald, S. & Leuschner, W. An analysis of the method for determining the lowest sensitivity of solarblind ultravio-let corona cameras. in 2020 International SAUPEC/RobMech/ PRASA Conference 1–6 (Cape Town, South Africa, 2020).    https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9040997
  19. Montgomery, D. C. & Runger, G. C. Applied Statistics and Probability for Engineers. (John Wiley and Sons, 2014).
  20. Coetzer, C., West, N., Swart, A. & van Tonder, A. An investigation into an appropriate optical calibration source for a corona camera. in 2020 International SAUPEC/RobMech/PRASA Conference 1–5 (IEEE, Cape Town, South Africa, 2020). https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9041014
  21. Chrzanowski, K. & Chrzanowski, W. Analysis of a blackbody irradiance method of measurement of solar blind UV cameras' sensitivity. Opto-Electron. Rev. 27, 378–384 (2019). https://doi.org/10.1016/j.opelre.2019.11.009
Go to article

Authors and Affiliations

Casper J. Coetzer
1
ORCID: ORCID
Nicholas West
2
ORCID: ORCID

  1. Dept. of Electrical, Electronic and Computer Engineering, University of Pretoria, Hatfield 0028, South Africa
  2. Dept. of Electrical and Information, University of Witwatersrand, 1 Jan Smuts Ave., Braamfontein 2000, Johannesburg, South Africa
Download PDF Download RIS Download Bibtex

Abstract

Hydrological models are widely used for runoff simulation throughout the world. The objective of this study is to check the performance of the HEC-HMS model for continuous runoff simulation of Gilgel Gibe watershed. It includes sensitivity analysis, calibration, and validation. The model calibration was conducted with data from the year 1991 to 2002 and validated for the year 2003 to 2013 period using daily observed stream flow near the outlet of the watershed. To check the consistency of the model, both the calibration and validation periods were divided into two phases. The sensitivity analysis of parameters showed that curve number (CN) and wave travel time (K) were the most sensitive, whereas channel storage coefficient (x) and lag time (tlag) were moderately sensitive. The model performance measured using Nash–Sutcliff Efficiency (NSE), Percentage of Bias (PBIAS), correlation coefficient (R2), root mean square error (RMSE), and Percentage Error in Peak (PEP). The respective values were 0.795, 8.225%, 0.916, 27.105 m3 s–1 and 7.789% during calibration, and 0.795, 23.015%, 0.916, 29.548 m3 s–1 and –19.698% during validation. The result indicates that the HEC-HMS model well estimated the daily runoff and peak discharge of Gilgel Gibe watershed. Hence, the model is recommended for continuous runoff simulation of Gilgel Gibe watershed. The study will be helpful for efficient water resources and watershed management for Gilgel Gibe watershed. It can also be used as a reference or an input for any future hydrological investigations in the nearby un-gauged or poorly gauged watershed.
Go to article

Authors and Affiliations

Sewmehon Sisay Fanta
1
ORCID: ORCID
Tolera Abdissa Feyissa
1
ORCID: ORCID

  1. Jimma University, Faculty of Civil and Environmental Engineering, Institute of Technology, Jimma, Ethiopia
Download PDF Download RIS Download Bibtex

Abstract

HPM meters are required for the assessment of fields generated by sources of high-power microwaves. Finding the inverse calibration curves for such instruments is important for ensuring accuracy. The procedure is relatively simple for meters consisting of linear devices but there can also be hardware solutions implementing nonlinear ones. The objective of the present work was to develop a convenient procedure to allow finding such a curve when the meter uses a D-dot probe and a power detector. For that purpose, the results of low voltage measurements describing the properties of the detector were first analysed. Then a software code was developed to estimate the RMS value of an incident field based on measured output and frequency response. The response was estimated with very low electric field. And finally, the performance of the proposed procedure was verified by tests conducted with high electric field in a TEM cell. High conformity of the output of the meter with fields of known values was demonstrated. The maximum error related to the meter range did not exceed 4%.

Go to article

Authors and Affiliations

Jacek Jakubowski
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

The Lithuanian national standard of electric resistance is maintained as the basis for calibration and measurement capabilities published in the key comparison database of the International Bureau of Weights and Measures (BIPM). The stability and uncertainty of the resistance value measurements, performed since 2004 using the calibrated values of the standard resistors to predict their future behaviour as well as influence of environmental conditions, are discussed. Also discussed is the recovery of a standard resistor which had undergone a mechanical disturbance. It is concluded that the standard resistors operated by the Lithuanian National Electrical Standards Laboratory feature stable drift of resistance, which is well predicted by means of linear regression.

Go to article

Authors and Affiliations

Andrius Bartašiunas
Rimantas Miškinis
Dmitrij Smirnov
Emilis Urba
Download PDF Download RIS Download Bibtex

Abstract

In this study, a digital manometer was used as a transfer standard to perform calibration of a pneumatic pressure balance. The same pressure balance was calibrated with the cross-floating method based on falling rate determination (FRD). Differences among the effective area results show an agreement of less than 10 ppm between the digital manometer-assisted calibration (DMAC) method and the FRD method. The method in which a digital pressure gauge is used as a transfer standard not only facilitates calibration but also enables the automation of pressure balance calibration. Full automation of pressure balance calibration requires an automatic mass loading system for both the reference instrument and the device under test. Since there is a lot of different kinds of pressure balances, it is nearly impossible for a pressure metrology laboratory to have an automatic mass-handler system for every type of pressure balance. Therefore, a more efficient way in which automated mass-handler systems are not required i.e., a semi-automatic calibration system, is designed. For that purpose, two different calibration procedures, increasing-decreasing cycles, and pressurize-vent (P-V) procedures are performed and compared. The equivalence of procedure results makes the semi-automated calibration design of pressure balances possible. The most distinguishing advantages of a semi-automated calibration system are the applicability to any type of pressure balance and low cost compared to full automation.
Go to article

Authors and Affiliations

Ahmet Türk
1
Abdullah Hamarat
1
Yasin Durgut
1

  1. TÜBITAK Ulusal Metroloji Enstitüsü, TÜBITAK Gebze Yerleskesi P.K.54 41470 Gebze, Kocaeli, Turkey
Download PDF Download RIS Download Bibtex

Abstract

Reference blocks are required for ultrasonic calibration and non-destructive testing (NDT). There are already in existence sets of reference blocks constructed according to American Society for Testing and Materials standards, but as the industry evolves, we need more reference blocks with varied designs. In this study, two reference blocks of steel and aluminum are constructed. These blocks have several sets of flat bottom holes (FBH) with different diameters (0.5, 1, 1.5, 2 and 2.5 mm), angles (45° and 90°) and placements. The novel constructed reference blocks are evaluated using the ultrasonic and a displacement measuring interferometer (DMI). They allow for detailed FBH characterization in terms of defining their location, diameter, depth and so on. The two techniques show consistency in the majority of the outcomes. The expanded uncertainty of readings is found to be ± 1.4 µm, according to DMI data. The findings show that the newly constructed blocks could be ideal for evaluating a variety of calibration factors including transducer sensitivity, dead zone, defect size, and depth. Furthermore, they can be used in NDT in various industries such as petroleum pipe production, steel manufacturing and so on.
Go to article

Authors and Affiliations

Mirham A.Y. Barakat
1
Mohamed Abdelwahab
2
Alshaimaa Waheed Abdallah
2

  1. Ultrasonic Metrology Laboratory, National Institute of Standards PO Box: 136, Giza code 12211, Tersa Street, Haram, Giza, Egypt
  2. Line & End Secondary Standards Laboratory, National Institute of Standards PO Box: 136, Giza code 12211, Tersa Street, Haram, Giza, Egypt
Download PDF Download RIS Download Bibtex

Abstract

Considering the low accuracy and low efficiency of the traditional calibration method for base strain sensitivity of accelerometers, a novel base strain sensitivity calibration system with steady harmonic excitation is proposed. The required cantilever beam for calibration is driven by an electromagnetic exciter to generate a base strain varying in a steady harmonic pattern. By applying a Wheatstone bridge circuit, the generated strain with low distortion can be measured. The measurement system with a compensation function can automatically calibrate the base strain sensitivity. The amplitude linearity and frequency response characteristics of the base strain sensitivity in two accelerometers are obtained experimentally, and the uncertainty in the results is 2% ( k = 2).
Go to article

Authors and Affiliations

Chuwei Ye
1

  1. The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang Province Key Laboratory of Advanced Manufacturing Technology, Zhejiang University, 310027, Hangzhou, China

This page uses 'cookies'. Learn more