The Study on the Internal Diameter Measuring System for the Small Bores

Author(s):  
Runzhong Miao ◽  
Zhanfang Chen ◽  
Rui Li ◽  
Zhiwen Yang ◽  
Shufang Wu
2019 ◽  
Vol 22 (4) ◽  
pp. 109-114
Author(s):  
Andrew A. Mosckalev ◽  
Ardi Rahman

Introduction. Increasing demands of precise geometry measurements by science and industry cause the necessity of improvement in an associated branch of legal and practical metrology. One of the most significant fields is the measurement of internal dimensions and so the issues with the unit of meter transfer. Now we face the situation when the current accuracies of National standards of different levels in corresponding traceability chain (reference rings measurements) get close to each other. This means that we have to make the standard of upper level more precise. One of the obvious ways is to apply the latest ultra-stable laser locked to a frequency comb.Objective. The objective is to propose possibilities for improvement of the National secondary standard of the unit of length by researching its measuring capabilities to minimize measurement uncertainty.Materials and methods. The calculation of expanded uncertainty of internal diameter measurements by the National secondary standard of the unit of length is performed according to the international document «Guide to the Expression of Uncertainty in Measurement» JCGM 100:2008 approved by BIPM. The secondary standard research results represented in previous reports and publications are also taken into consideration.Results. Detailed uncertainty budget for the proposed measuring system is given as well as graphical data representing the accuracy improvement.Conclusion. Actions for minimization of measurement uncertainty components of the National secondary standard of the unit of length in the field of reference ring internal diameter measurements in combination with state-of-the-art laser interferometer system improve it to the next frontiers of accuracy and precision.


2019 ◽  
Vol 42 (4) ◽  
pp. 823-831
Author(s):  
Mahammed Arif Sanjid ◽  
Sanjoy K Ghoshal ◽  
Mrinal Sen

Key comparison measurements serve as an ultimate tool of quality assurance of results. Whenever the inter-comparison results indicate inconsistency, the participating laboratory needs to take the corrective actions. Practically, the systematic errors involved in the measuring system confines the achievable accuracy. Therefore, the corrective action involves either empirically determine the influences afresh or intuitively reassigns these error values. Alternatively, an analytical method based on inter laboratory comparison results is proposed. The novelty of the proposal is considering task-specific errors in the model that is used for the analysis of interlaboratory comparison results. Without accounting the uncertainties of task-specific errors, the analysis grows complicated and even sometimes it is not feasible. To supplement the proposed method, task-specific errors due to the imperfect geometry of ring gauge, practical inability in implementing the measurement, and unattended environmental influences are explored. The proposed method is demonstrated using some internal diameter key comparison data. The systematic errors responsible for the outlier in the measurement comparison are clearly distinguished.


Author(s):  
Liqiong Tang ◽  
Morio Fukuoka ◽  
Peter Tait

Reformer tubes are commonly used in process industry. They are high cost components. The service life of reformer tubes is primarily determined by creep damage. To successfully manage the reformer tubes requires balancing creep life against the production gains of higher temperatures. The key to this requires an ongoing knowledge of the condition of the tubes. Monitoring the diametrical change of the tubes caused by creep damage is one of the most popular methods used in industry. However, the available reformer tube diametrical checking systems are very expensive. This paper presents a novel mechanical sensing unit for reformer tube diametrical measuring. The system is low cost and meets the industrial company specified requirements. Test and field trials made on the prototype gave a very encouraging result. With further study, it is expected that a robust and cost effective reformer tube diametric measuring system can be developed.


1995 ◽  
Vol 73 (05) ◽  
pp. 850-856 ◽  
Author(s):  
F D Rubens ◽  
D W Perry ◽  
M W C Hatton ◽  
P D Bishop ◽  
M A Packham ◽  
...  

SummaryPlatelet accumulation on small- and medium-calibre vascular grafts plays a significant role in graft occlusion. We examined platelet accumulation on the surface of fibrin-coated polyethylene tubing (internal diameter 0.17 cm) during 10 min of flow (l0ml/min) at high wall shear rate (764 s-1). Washed platelets labelled with 51Cr were resuspended in Tyrode solution containing albumin, apyrase and red blood cells (hematocrit 40%). When the thrombin that was used to form the fibrin-coated surface was inactivated with FPRCH2C1 before perfusion of the tubes with the platelet:red blood cell suspension, the accumulation of platelets was 59,840 ± 27,960 platelets per mm2, whereas accumulation on fibrin with residual active thrombin was 316,750 ± 32,560 platelets per mm2 (n = 4). When the fibrin on the surface was cross-linked by including recombinant factor XIII (rFXIII) in the fibrinogen solution used to prepare the fibrin-coated surface, platelet accumulation, after thrombin neutralization, was reduced by the cross-linking from 46,974 ± 9702 to 36,818 ± 7964 platelets per mm2 (n = 12, p <0.01). Platelet accumulation on tubes coated with D-dimer was ten times less than on tubes coated with D-domain; this finding also supports the observation that cross-linking of fibrin with the formation of γ-γ dimers reduces platelet accumulation on the fibrin-coated surface. Thrombin-activated platelets themselves were shown to cross-link fibrin when they had adhered to it during perfusion, or in a static system in which thrombin was used to form clots from FXIII-free fibrinogen in the presence of platelets. Thus, cross-linking of fibrin by FXIII in plasma or from platelets probably decreases the reactivity of the fibrin-containing thrombi to platelets by altering the lysine residue at or near the platelet-binding site of each of the γ-chains of the fibrinogen which was converted into the fibrin of these thrombi.


2020 ◽  
pp. 38-44
Author(s):  
A. V. Polyakov ◽  
M. A. Ksenofontov

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.


2020 ◽  
Vol 29 (8) ◽  
pp. 57-61
Author(s):  
V.Y. Chernykh ◽  
◽  
E.V. Karpushina ◽  
N. Yu. Bykova ◽  
A.S. Maksimov ◽  
...  
Keyword(s):  

2017 ◽  
Vol 2017 (45) ◽  
pp. 83-89
Author(s):  
A.A. Marusenkov ◽  

Using dedicated high-frequency measuring system the distribution of the Barkhausen jumps intensity along a reversal magnetization cycle was investigated for low noise fluxgate sensors of various core shapes. It is shown that Barkhausen (reversal magnetization) noise intensity is strongly inhomogeneous during an excitation cycle. In the traditional second harmonic fluxgate magnetometers the signals are extracted in the frequency domain, as a result, some average value of reversal magnetization noises is contributed to the output signals. In order to fit better the noise shape and minimize its transfer to the magnetometer output the new approach for demodulating signals of these sensors is proposed. The new demodulating method is based on information extraction in the time domain taking into account the statistical properties of cyclic reversal magnetization noises. This approach yields considerable reduction of the fluxgate magnetometer noise in comparison with demodulation of the signal filtered at the second harmonic of the excitation frequency.


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