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A geostress measurement method based on an integrated drilling and optical microscopic imaging system
Jinchao Wang, Chunying Wang, Zengqiang Han, Yiteng Wang, Xinjian Tang, 2018, izvirni znanstveni članek

Opis: Conventional geostress measurement methods are limited by deficiencies including the measurable depth, the complexity, and the long duration of operation. To address these problems and achieve the measurement of geostress in deep wells under conditions of complex high pressures and high temperatures, we propose a new measurement method for geostress based on an integrated drilling and optical microscopy system. Its innovative integrated structure eliminates the problems associated with complex procedures and depth limits, and avoids rock creep caused by long delays, significantly improving the accuracy and range of the measurements. It works by using microscopic imaging and direct contact probes to capture the changes of a borehole’s cross-sectional outlines before and after stress relief. The resulting images are analyzed with search circles to obtain the positions of probe apices, which can be fitted into ellipses that describe the outlines, and calculate the state of the stress. The validity and accuracy of the method was verified by in-door tests and field applications in the ZK1 borehole. The results show that: (1) the integrated system can be used to measure micrometer-grade deformations; (2) the searchcircle approach can accurately obtain the positions of probe apices; and (3) the stress measurement method based on the system is accurate and feasible.
Ključne besede: geostress, probe, optical microscopy, measurement while drilling, search circle
Objavljeno: 11.10.2018; Ogledov: 624; Prenosov: 298
.pdf Celotno besedilo (1,26 MB)
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3D response of an excavation adjacent to buildings supported by inclined struts
Zahra Sabzi, Ali Fakher, 2017, izvirni znanstveni članek

Opis: The presented study focuses on field observations and a 3D numerical analysis of open-cut excavations adjacent to a building supported by inclined struts. The performance of the struts in carrying the building loads and decreasing the deflections is investigated. Struts reduce the amount of deformations and also create a corner effect similar to the diaphragm walls corner. The influence of the distance between the struts is studied and the optimum struts interval is proposed. The most effective configuration of struts installation in reducing the deflections and building damage is proposed. A displacement-based design guideline is also presented based on the results of numerical studies.
Ključne besede: measurement, 3D finite-element analysis, displacement-based design
Objavljeno: 18.06.2018; Ogledov: 357; Prenosov: 41
.pdf Celotno besedilo (2,85 MB)
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Prediction of the pile behaviour under dynamic loading using embedded strain sensor technology
Andrej Štrukelj, Mirko Pšunder, Helena Vrecl-Kojc, Ludvik Trauner, 2009, izvirni znanstveni članek

Opis: A standard dynamic loading test of the pile was performed on the highway section Slivnica - Hajdina near Maribor, Slovenia. Parallel to standard testing procedures the new monitoring technology based on specially developed strain sensors installed inside the pile body along the pile axis was introduced. On the basis of the measured results the normal strains along the pile axis were measured. Taking into consideration the elastic modulus of the concrete the normal stresses in the axial direction of the pile were also calculated and afterwards the shear stresses along the pile shaft have been estimated as well as the normal stresses below the pile toe. The estimation was made by considering a constant value for the pile diameter. The measured results were also compared with the computer simulation of the pile and the soil behaviour during all the successive test phases. The strain measurements inside the pile body during the standard dynamic loading test in present case did not have the purpose of developing an alternative method of pile loading tests. The presented monitoring technology proved itself as a very accurate and consistent. It gave in the first place the possibility of a closer look at the strains and stresses of the most unapproachable parts of different types of concrete structure elements especially piles and other types of deep foundations.
Ključne besede: piles, deep foundations, dynamic loading test, strain measurement technologies, elasto-plastic modelling, finite-element method
Objavljeno: 06.06.2018; Ogledov: 464; Prenosov: 48
.pdf Celotno besedilo (780,04 KB)
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Development of smart energy meter using arm platform
Darijo Topić, 2017, magistrsko delo

Opis: This master thesis describes the development of smart electricity energy meter on the ARM platform. In general, the commercial electrical energy meters are measuring only the total active energy, therefore, users cannot also monitor other important power consumption parameters. The goal of this thesis is to develop a prototype of smart ARM based energy meter, which is capable to measure several power consumption parameters and display them on a webpage in real-time. In the thesis the complete design of the ARM based smart energy meter is presented in detail. Further, the development of user interface for displaying measured data on the webpage in real-time is also presented. These results are presented both in textual and graphical form. Additionally, the theory of electric power consumption measurements and some commercial energy meters are presented.
Ključne besede: energy meter, ARM processor, power consumption, internet of things, calibration, green environment, energy consumption measurement, emoncms
Objavljeno: 16.11.2017; Ogledov: 1198; Prenosov: 227
.pdf Celotno besedilo (5,10 MB)

Measuring efficiency of nations in multi sport events
Roma Mitra Debnath, Ashish Malhotra, 2015, izvirni znanstveni članek

Opis: This paper used a data envelopment analysis (DEA) to measure the performance of the nations participating in the Commonwealth Games. To increase the consistency of the research, multiple models were employed to validate the result, but the nature of the input and output remained same throughout the paper. The objective of this study was to establish some realistic targets in terms of number of players for all participant countries and evaluations of their performance as well as benchmarks against the most efficient country. This study would help the nations optimize the size of their players to maximize the outcome in terms of the number of medals won in sporting events.
Ključne besede: performance measurement, data envelopment analysis, efficiency, Commonwealth Games
Objavljeno: 13.11.2017; Ogledov: 643; Prenosov: 75
.pdf Celotno besedilo (1,51 MB)
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Suitability of the double Langevin function for description of anhysteretic magnetization curves in NO and GO electrical steel grades
Simon Steentjes, Martin Petrun, G. Glehn, Drago Dolinar, Kay Hameyer, 2017, izvirni znanstveni članek

Opis: This paper compares the match obtained using the classical Langevin function, the tanh function as well as a recently by the authors proposed double Langevin function with the measured anhysteretic magnetization curve of three different non-oriented electrical steel grades and one grain-oriented grade. Two standard non-oriented grades and a high-silicon grade (Si content of 6.5%) made by CVD are analyzed. An excellent match is obtained using the double Langevin function, whereas the classical solutions are less appropriate. Thereby, problems such as those due to propagation of approximation errors observed in hysteresis modeling can be bypassed.
Ključne besede: polarization, magnetization measurement, magnetic materials, hysteresis models, Langevin function, electrical steel, saturation
Objavljeno: 03.08.2017; Ogledov: 549; Prenosov: 329
.pdf Celotno besedilo (652,05 KB)
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Railway noise reduction by the application of CHFC material on the rail
Brigita Altenbaher, Darja Goltnik, Bojan Rosi, 2015, izvirni znanstveni članek

Opis: Traffic is the most widespread source of environmental noise. Railway noise has become increasingly common in urban areas in the past few decades. Therefore environmental requirements for railway operations regarding noise are becoming very strict and will become even tighter in future. In the present paper we present actual track- based field test performed on Slovenian Railways. The significant noise reduction (up to 30dBA) was achieved by the application of CHFC material on the rail using CL-E1 top anti noise system.
Ključne besede: noise reduction, rail, measurement, anti noise system
Objavljeno: 17.07.2017; Ogledov: 737; Prenosov: 326
.pdf Celotno besedilo (864,19 KB)
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From DCOM interfaces to domain-specific modeling language
Tomaž Kos, Tomaž Kosar, Jure Knez, Marjan Mernik, 2011, izvirni znanstveni članek

Opis: Software development is a demanding process, since it involves different parties to perform a desired task. The same case applies to the development ofmeasurement systems - measurement system producers often provide interfaces to their products, after which the customersć programming engineers use them to build software according to the instructions and requirements of domain experts from the field of data acquisition. Until recently, the customers of the measurement system DEWESoft were building measuring applications, using prefabricated DCOM objects. However, a significant amount of interaction between customersć programming engineers and measurement system producers is necessary to use DCOM objects. Therefore, a domain-specific modeling language has been developed to enable domain experts to program or model their own measurement procedures without interacting with programming engineers. In thispaper, experiences gained during the shift from using the DEWESoft productas a programming library to domain-specific modeling language are provided together with the details of a Sequencer, a domain-specific modeling language for the construction of measurement procedures.
Ključne besede: domain specific modelling language, data acquisition, measurement systems
Objavljeno: 06.07.2017; Ogledov: 667; Prenosov: 92
.pdf Celotno besedilo (465,80 KB)
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New quartz oscillator switching method for nano-Henry range inductance measurements
Vojko Matko, Karel Jezernik, 2012, izvirni znanstveni članek

Opis: This article introduces a new method for nano-Henry inductance measurements atthe frequency of 4.999 MHz with a single quartz crystal oscillating in the switching oscillating circuit. The real novelty of this method, however, lies in a considerable reduction of the temperature influence of AT-cut crystal frequency change in the temperature range between 0 °C and 50 °C through a switching method which compensates for the crystalćs natural temperature characteristics. This allows for the compensation of any influences on the crystal such as the compensation of the non-linear temperature characteristicsand the ageing of both the crystal and other oscillating circuit elements, as well as the reduction of the output frequency measurementerrors with the help of an additional reference frequency. The experimental results show that the switching method greatly improves the measurement of small inductance changes in the range between H and nH, allowing as a result high-precision measurements (~0.35 fH) in this range.
Ključne besede: quartz crystal, switching oscillating method, nano-Henry range measurement
Objavljeno: 22.06.2017; Ogledov: 481; Prenosov: 303
.pdf Celotno besedilo (872,06 KB)
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MOS-FET as a current sensor in power electronics converters
Rok Pajer, Miro Milanovič, Branko Premzel, Miran Rodič, 2015, izvirni znanstveni članek

Opis: This paper presents a current sensing principle appropriate for use in power electronics’ converters. This current measurement principle has been developed for metal oxide semiconductor field effect transistor (MOS-FET) and is based on UDS voltage measurement. In practice, shunt resistors and Hall effect sensors are usually used for these purposes, but the presented principle has many advantages. There is no need for additional circuit elements within high current paths, causing parasitic inductances and increased production complexity. The temperature dependence of MOS-FETs conductive resistance RDS−ON is considered in order to achieve the appropriate measurement accuracy. The “MOS-FET sensor” is also accompanied by a signal acquisition electronics circuit with an appropriate frequency bandwidth. The obtained analogue signal is therefore interposed to an A-D converter for further data acquisition. In order to achieve sufficient accuracy, a temperature compensation and appropriate approximation is used (RDS−ON = RDS−ON(Vj)). The MOS-FET sensor is calibrated according to a reference sensor based on the Hall-effect principle. The program algorithm is executed on 32-bit ARM M4 MCU, STM32F407.
Ključne besede: power electronics, converters, MOS-FET, current measurement, thermal model
Objavljeno: 22.06.2017; Ogledov: 740; Prenosov: 281
.pdf Celotno besedilo (1,32 MB)
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