Study on the Measuring Instruments and Strength Size Effect of the Surface Shape of Rigid Structure Plane

2011 ◽  
Vol 250-253 ◽  
pp. 2327-2332
Author(s):  
Feng Ji ◽  
Yu Chuan Shi
Keyword(s):  
Size Effect ◽  
Precise Measurement ◽  
Rock Sample ◽  
Surface Shape ◽  
Measuring Instruments ◽  
Rigid Structure ◽  
Advantages And Disadvantages ◽  
Structure Surface ◽  
Structure Plane ◽  
Working Efficiency

The surface shape of structure plane is closely related with its mechanics property. Precise measurement to the surface shape of structure plane is the basis of deformation mechanism and strength characteristics. On the basis of studying advantages and disadvantages of the measuring instrument, the author has developed a new kind of portable measuring instruments innovatively - Contact Punching Device which has improved open-air working efficiency greatly. Application results show that JRC obtained by the Contact Punching Device is very close to the actual JRC of surface shape of the structure plane. Then about size effect of rigid structure plane, got the following principle that the statistical variance of the undulating roughness of the structure surface decays gradually with length of the rock sample, and got the limiting length of the undulating roughness when the influence of shearing intensity of the structure is dispelled. Finally, which proved through the embodiment of different rock and different weathering rock, the result indicates this method can be applied to engineering.

scholarly journals MECHANICAL STRENGTH OF COAL: METHODS OF DETERMINATION AND FACTORS OF INFLUENCE (REVIEW)

2021 ◽  
Vol 6 ◽  
pp. 4-17
Author(s):  
V.V Koval ◽  
D.V. Miroshnichenko ◽  
O.V. Bogoyavlenska
Keyword(s):  
Mechanical Strength ◽  
Physical Properties ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
Point Of View ◽  
Statistical Characteristics ◽  
Measuring Instruments ◽  
Industrial Processing ◽  
Average Value ◽  
Advantages And Disadvantages

The article substantiates the importance and problems of determining of such an indicator of the quality of solid fossil fuels, as mechanical strength. The strength of coal depends on a large number of factors (viscosity, brittleness, properties of structural bonds, etc.), the change of which is impossible to take into account. Therefore, the strength of coal in the sample, piece, pack and formation must be represented by some integral index, which inevitably fluctuates around a certain average value and can be determined only approximately. The evaluation of the strength properties of coal should be carried out on the basis of mass tests using statistical methods that allow to calculate the average value and coefficient of variation. Since the strength dispersion is mainly due to the natural inhomogeneity of the coal, the excessive accuracy of the measuring instruments has almost no effect on the statistical characteristics. Laboratory methods of mechanical tests of mine samples, in comparison with full-scale, as a rule, are very accessible and, at qualitative performance of tests, are highly reliable. The properties of coal as an object of enrichment and use are largely related to its physical properties. The physical properties of coal and mineral impurities significantly affect the formation of the main parameters that characterize the particle size distribution and fractional composition, it`s changes during the mining, transportation and enrichment processes. The basic physical and mechanical properties of solid fuels from the point of view of their industrial processing have been listed, the review has been made of the most widespread methods of study of coals mechanical durability and the equipment used for these purposes. The main advantages and disadvantages have been summarized of these methods, as well as their relationship. The factors have been Indicated tinfluencing the mechanical strength of coal. The expediency of using existing methods from the point of view of informativeness for thesphere of its application has been estimated. The methods common in the coal processing industry are considered in more detail. Keywords: coal, solid fuel mining, mechanical strength, determination methods, influencing factors, grinding strength, crushing index. Corresponding author V.V. Koval, e-mail: [email protected]

Research on the Online Test Principle and Error Analysis of Aspherical Optical Surfaces

2013 ◽  
Vol 552 ◽  
pp. 434-439
Author(s):  
Da Mu ◽  
Quan Yong Li ◽  
Bo Qi Wu ◽  
Yu Nan Du
Keyword(s):  
High Precision ◽  
Precision Measurement ◽  
Measurement Errors ◽  
Surface Shape ◽  
High Precision Measurement ◽  
Aspherical Surface ◽  
Optical Surfaces ◽  
Advantages And Disadvantages ◽  
Swing Arm ◽  
Key Factor

For tFor t For tFor the imaging advantages of aspheric optical component, it has been widely used in the aviation, aerospace, defense and civilian high-technology. Aspherical surface shape test is a key factor restricted aspheric processing and a complex sophisticated testing techniques. The well known measurement methods are faulty. Each method has advantages and disadvantages; many methods cannot be used for online testing. In this paper，the geometric principle of a swing-arm profilometer as a novel method to measure aspherics is introduced．The deviation between the actual and the ideal of aspherical surface shape is confirmed by the high-precision measurement for the vertical height with a specific path on the aspherical optical surfaces. By adjusting the location of measuring devices to maintain the distance of rotation center to the center of workpiece equal to the length of swing-arm,we can achieve the measurement for the workpiece of different machining tool. The measurement system mainly consists of the lifting and landing system of the high-precision axis,the high-precision level turntable rotary table, the high rigidity measuring arm and the high precision measurement sensors. And the follow-up data processing puts forward a number of error correction models at the same time. The advantages of the measurement method are that the measurement sports is only a simple turning motion .It will be helpful to reduce measurement errors and improve the efficiency of measurement.

Diagnostics of aviation equipment. Methods and means of non-destructive testing of the technical condition of the aircraft

2017 ◽  
Author(s):  
Мартыненко ◽  
Elena Martynenko
Keyword(s):  
Physical Nature ◽  
Optical Devices ◽  
Civil Aviation ◽  
Measuring Instruments ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Ray Method ◽  
Advantages And Disadvantages ◽  
Non Destructive

This manual contains information about the appointment and the physical nature of the application existing non-destructive testing methods, their advantages and disadvantages. The manual contains a brief historical information about the development of non-destructive testing methods in manufacturing aircraft devices, the classification and possible causes of occurrence of various defects on which the studied method of non-destructive testing are directed. The first part of the manual, of the main methods that are used to detect the defects in any instrument control. The detailed classification of measuring instruments and optical devices are given. Moreover, the construction and the ways (the principles) of work of complex measuring instruments and optical devices, including endoscopes are given. The current devices and systems for visual inspection of fiber-hidden objects and internal cavities are considered. More detailed consideration in the manual is given to the capillary, magnetic, acoustic, eddy current non-destructive testing methods and techniques of radiographic(X-ray and gamma-ray method). Particular attention is paid to the field of practical application of different methods. A lot of attention is given to modern means of non-destructive testing of domestic and foreign production. The manual contains a significant amount of drawings and diagrams, which allows to increase the visibility and the accessibility of presentation. It is drawn up with the interdisciplinary course program MDK 01.01.03 "Technical maintenance of aircraft and engines" and is intended for students of the above mentioned specialization 25.02.01 branches of secondary vocational education. The manual can also be used by the students of the training courses for engineering and technical personnel of the enterprises of civil aviation.

Use of newly developed instruments and endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach

2007 ◽  
Vol 6 (6) ◽  
pp. 521-530 ◽  
Author(s):  
Sebastian Ruetten ◽  
Martin Komp ◽  
Harry Merk ◽  
Georgios Godolias
Keyword(s):  
Minimally Invasive ◽  
Lumbar Disc ◽  
Invasive Procedure ◽  
Leg Pain ◽  
Herniated Disc ◽  
Measuring Instruments ◽  
Minimally Invasive Procedure ◽  
Technical Problems ◽  
Endoscopic Techniques ◽  
Advantages And Disadvantages

Object Even with good results, conventional disc operations may result in subsequent damage due to trauma. Endoscopic techniques have become the standard in many areas because of the advantages they offer intraoperatively and postoperatively in rehabilitation. The goal of this prospective study was to examine the expanded technical possibilities of full-endoscopic transforaminal and interlaminar resection of herniated lumbar discs in which the authors used newly developed optics and instruments. The focus was on questions of achieving sufficient decompression, as well as the advantages and disadvantages of the minimally invasive procedure. Methods Two hundred thirty-two patients underwent follow up for 2 years after undergoing surgery. In addition to general and specific parameters, the following measuring instruments were used: a visual analog scale, the German version of the North American Spine Society instrument, and the Oswestry Disability Index of low-back pain disability. Postoperatively 84% of the patients no longer had leg pain, and 12% had only occasional pain. The results of decompression were equivalent to those of conventional procedures. The incidence of traumatization was reduced. Epidural scarring was minimized. The recurrence rate was 6.0%. No serious surgical complications were observed. Resection of the herniated disc was technically possible in all cases in which the new instruments were used. Conclusions The authors view the aforedescribed techniques, which offer the advantages of a truly minimally invasive procedure, as a sufficient and safe supplementation and alternative to conventional procedures, when the appropriate indication criteria are heeded. The new endoscope with its 4.2-mm working channel and corresponding instruments significantly reduced the technical problems.

AN OVERVIEW OF IMPORTANT FACTORS TO CONSIDER WHEN CALIBRATING LEDS IN PHOTOMETRY WITH DIFFERENT DETECTORS

2021 ◽  
Author(s):  
T. Gerloff ◽  
L. Ulm ◽  
P. Sperfeld ◽  
A. Sperling
Keyword(s):  
Measuring Equipment ◽  
Imaging Systems ◽  
Fluorescent Light ◽  
Measuring Instruments ◽  
Light Sources ◽  
White Leds ◽  
Advantages And Disadvantages ◽  
Measuring Devices ◽  
Double Monochromator ◽  
Physical Quantities

LED-based lighting products are the fastest developing light sources on the general lighting market. These include not only white light sources, but also coloured light sources. SI-traceable calibrations with a low measurement uncertainty are challenging because their unique spectral and geometric properties must be taken into account. The requirements on the measuring equipment and resulting uncertainty contributions differ significantly from those for the calibration of conventional incandescent or fluorescent light sources. Furthermore, different detector types can be used when calibrating LEDs. These include classic photometers, radiometers, spectroradiometers but also imaging systems such as ILMDs. Each of these measuring devices has its specific advantages and disadvantages. In this paper, traceable calibrations on 9 coloured and 9 white LEDs are discussed. Various array spectroradiometers, photometers, radiometers and a double monochromator were used for this purpose. Each of these measuring instruments is discussed in terms of its suitability for measuring different physical quantities (e.g. array spectrometer for measuring illuminance).

PROSPECTS FOR THE USE OF SURFACE WAVE LINES IN LOCAL DATA NETWORKS

2020 ◽  
Author(s):  
Н.В. ЛЕМЕШКО ◽  
С.С. ЗАХАРОВА
Keyword(s):  
Surface Wave ◽  
Spatial Separation ◽  
Point Of View ◽  
Data Networks ◽  
Measuring Instruments ◽  
Electromagnetic Environment ◽  
Local Data ◽  
Transmission Networks ◽  
Advantages And Disadvantages ◽  
Physical Principles

Оценивается перспектива использования линий поверхностной волны в локальных сетях передачи данных. Кратко рассмотрена физика работы такихлиний, показаны их достоинства и недостатки с точки зрения указанного применения. На основе известного способа возбуждения поверхностной волны предложен подход к контролю ее наличия с применением типовых средств измерений, предусматривающий формирование отраженной поверхностной волны и использование циркулятора. Представлена информация о конструкции рупорного перехода с боковым питанием и подстройкой, обеспечивающими узкополосное согласование, необходимое при работе линий поверхностной волны в условиях сложной электромагнитной обстановки либо их массового применения при ограниченном пространственном разносе. The article assesses the prospect of using surface wave lines in local data transmission networks. The physical principles of operation of such lines are briefly considered, their advantages and disadvantages from the point of view of the indicated application are shown. Based on the known method of surface wave excitation, an approach is proposed to control its presence using standard measuring instruments, which involves the formation of a reflected surface wave and the use of a circulator. Information is presented on the design of a horn junction with lateral power supply and adjustment, providing nar-row-band matching required for the operation of surface wave lines in a difficult electromagnetic environment or their widespread use with a limited spatial separation.

Measuring Servant Leadership

2014 ◽  
pp. 211-242
Author(s):  
Claudio Pousa
Keyword(s):  
Servant Leadership ◽  
Final Section ◽  
Scientific Literature ◽  
Operational Definition ◽  
Clear Picture ◽  
Measuring Instruments ◽  
Advantages And Disadvantages ◽  
Robert Greenleaf ◽  
Definition Of

The concept of Servant Leadership was introduced by Robert Greenleaf in the 1970s, and although in his works there is a very clear picture of servant leadership in philosophical terms, there is not an empirically validated definition of servant leadership. For this reason, numerous scholars worked individually on developing competing frameworks to define servant leadership since the mid-1990s; the result is that, throughout the scientific literature, the construct of servant leadership is defined by an inconsistent set of dimensions and there is still no consensus about an operational definition of the construct. In a similar way, since the end of the 1990s, numerous scholars developed different scales to measure servant leadership, based on different operational definitions. Accordingly, there is not an agreed upon measure of Servant Leadership; a few measures were used in a limited number of studies, and a relatively large number of measures were used in less than two. The chapter presents the most significant and used operational definitions, a detailed description of the development of the different measuring instruments, as well as a reference to some of the studies that used them, and a final section where the advantages and disadvantages of using certain measures are presented.

scholarly journals A New Method for Measuring Flow Structure in the Benthic Boundary Layer Using an Acoustic Doppler Velocimeter

2008 ◽  
Vol 25 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Tetsunori Inoue ◽  
Yoshiyuki Nakamura ◽  
Mikio Sayama
Keyword(s):  
Flow Structure ◽  
Precise Measurement ◽  
Shear Velocity ◽  
Turbulent Energy ◽  
Sediment Surface ◽  
Benthic Boundary Layer ◽  
Acoustic Doppler Velocimeter ◽  
Vertical Profiles ◽  
Advantages And Disadvantages ◽  
Turbulent Flow Structure

Abstract A new system for precise measurement of vertical profiles of mean and turbulent flow structure immediately above the sediment–water interface is introduced. This system has an acoustic Doppler velocimeter (ADV) attached to an elevation system to allow for the precise measurement of the vertical profiles of three-component velocities in the range of 0.1–27 cm above the sediment surface in the field. This system enables an onboard operator to accurately measure height and move the ADV vertically to any point. The system was applied to in situ measurements of velocity profiles immediately above the sediment. The shear velocity, Reynolds stress value, roughness height, turbulent kinetic energy, and dissipation rate of turbulent energy were calculated and compared with often-cited values. The results showed the same flow properties as those from laboratory experiments and literature values. The advantages and disadvantages of the system are discussed.

Deformation of a Thermocapillary Driven Liquid Bridge

2005 ◽  
Author(s):  
Brent C. Houchens ◽  
John S. Walker
Keyword(s):  
Free Surface ◽  
Liquid Bridge ◽  
Numerical Models ◽  
Dynamic Pressure ◽  
Surface Shape ◽  
Leading Order ◽  
Advantages And Disadvantages ◽  
Float Zone ◽  
Free Surface Shape ◽  
Physical Insight

Predicting the free-surface shape of a liquid bridge has been the focus of several recent models of containerless semiconductor crystal-growth methods, such as float-zone processing. We wish to sort out the discrepancies in the predictions of the numerical models by investigating the physics of a simplified system, the half-zone in microgravity. In the absence of gravity, the deformation of the free surface is small. Therefore, we first calculate the flow for a cylindrical melt region, corresponding to a large reference surface tension. This problem is well benchmarked, and the results are in nearly universal agreement. We then investigate a small perturbation of the free-surface shape using the flow calculated for the undeformed liquid bridge. Applying asymptotic expansions, we can predict the leading order of the free-surface velocities and deformation. In this formulation, it is easy to understand the relevance of each term, including the dynamic pressure variation. This solution is also more efficient than the numerical schemes that iterate between the shape of the free surface and the associated flow field. Furthermore, it provides physical insight that is difficult to extract from a purely numerical solution. Conversely, it is an approximation and therefore neglects terms of importance to a highly deformed free surface. Where possible, we will compare the leading-order free-surface shape to that predicted by numerical models, and discuss the advantages and disadvantages of this technique.

scholarly journals Design of Industrial Standards for the Calibration of Optical Microscopes

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 29
Author(s):  
Alberto Mínguez Martínez ◽  
Cecilia Gómez Pérez ◽  
David Canteli Pérez-Caballero ◽  
Laura Carcedo Cerezo ◽  
Jesús de Vicente y Oliva
Keyword(s):  
Surface Characterization ◽  
Precise Measurement ◽  
Metrological Traceability ◽  
Measuring Instruments ◽  
Fields Of Study ◽  
Optical Measuring ◽  
Metrological Control ◽  
Focus Variation ◽  
Industrial Standards

One of the most important fields of study in material science is surface characterization. This topic is currently a field of growing interest as many functional properties depend on the surface texture. In this paper the authors, after a short a review of different methods for surface topography characterization and the determination of the traceability problems that arise in this type of measurements, propose four different designs of material standards that can be used to calibrate the most common optical measuring instruments used for these tasks, such as measuring microscopes, metallurgical microscopes, confocal microscopes, focus variation microscopes, etc. The authors consider that the use of this type of standards (or others similar to them) could provide a step forward in assuring metrological traceability for different metrological characteristics that enables a more precise measurement of surface features with optical measuring instruments. In addition, authors expect that this work could lay the groundwork for the development of custom standards with specialized features tuned to gain a better metrological control when measuring specific geometrical surface properties.

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