Accurate and fast access to Vernier caliper readings is a critical issue in automated verification of Vernier calipers. To address this problem, this paper proposes a machine vision-based algorithm for reading the Vernier caliper’s displayed value. The suggested method first employs threshold segmentation and template matching to determine the region of interest and obtain the main ruler digit position by alternate projection. Then, we apply the improved LeNet5 network to identify the main ruler of the Vernier caliper, Moreover, we developed the first and last inscription method for reading the decimal part of the Vernier caliper and established our data set for model training. Extensive experiments on reading the displayed value have demonstrated our algorithm’s accuracy, which achieves a displayed value reading accuracy of 100%. Compared to other methods, the proposed technique affords better stability and accuracy.
As part of the work the high-pressure sorptomat - a novel apparatus for sorption tests under conditions of high gas pressure was developed. The sorption measurement is carried out using the volumetric method, and the precise gas flow pressure regulator is used in the device to ensure isobaric conditions and regulate the sorption pressure in the range of 0-10 MPa. The uniqueness and high precision of sorption measurements with the constructed apparatus are ensured by the parallel use of many pressure sensors with a wide measurement range as well as high precision of measurement - due to the use of precise pressure sensors. The obtained results showed, i.a. that the time of reaching the isobaric conditions of the measurement is about 6-7 seconds and it is so short that it can be considered a quasi-step initiation of sorption processes. Moreover, the results of the measurement pressure stabilization tests, during the CO 2 sorption test on activated carbon, have shown that the built-in pressure regulator works correctly and ensures isobaric sorption measurement conditions with the precision of pressure stabilization of ±1% of the measurement pressure. The maximum range of sorption measurement using the high-pressure sorptomat is 0-86400 cm 3/g, and the maximum measurement uncertainty is ±2% of the measured value. The activated carbon sample used for the tests was characterized by a high sorption capacity, reaching 104.4 cm 3/g at a CO 2 pressure of 1.0 MPa.
In recent years, the Steer-by-Wire (SBW) technology has been gaining popularity and replacing classical steering systems. It plays the most crucial role in autonomous cars where the vehicle must perform maneuvers on its own without driver’s intervention. One of the key components of this system is the steering wheel angle sensor (SAS). Its reliability and performance may affect driver’s life and health. The purpose of this paper is to show a test system to comprehensively evaluate the performance of the steering wheel angle sensor in the SBW system during real-world maneuvers and show how SAS parameters such as accuracy of angle, angular speed etc. affect car trajectory resulting in hit cones. For this purpose, a test system was built, with the use of virtual test drives based on CarMaker software, CANoe and VTSystem hardware. In order to evaluate its performance, the errors introduced by the system were determined. Additionally, using the realised test system, three commercial steering wheel angle sensors were tested and compared during a virtual test drive. Their errors were determined, as well as their performance in the SBW technology and the consistency of the obtained results with the parameters declared by the manufacturer were verified as well.
AGH University of Science and Technology, Faculty of Mechanical Engineering and Robotics, al. A. Mickiewicza 30, 30-059 Kraków, Poland
AGH University of Science and Technology, Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering, al. A. Mickiewicza 30, 30-059 Kraków, Poland
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.
The article shows the possibility of using TFBG gratings to measure the radius of curvature of fiber bending in conditions of variable polarization of the introduced light. Most of the modern, stable light sources generate light with a high degree of polarization. Due to the spatial asymmetry, the direction of the light polarization plane affects the spectral parameters of individual modes. For this reason, in the measurement systems using TFBGs presented so far it becomes necessary to determine and control the state of light polarization directly in front of the periodic structure. The article presents the determined spectral parameters of the cladding modes which allow bending measurements regardless of the direction of polarization of the introduced light. Thanks to this, the measuring system can be constructed without providing control of the introduced light polarization angle, which makes its construction simpler. When using TFBGs with an angle of 2°, the accuracy of determining the bending radius in the range from 15 mm to 30 mm when changing the angle of the plane of polarization in the full range is 0.318 mm in the case of changes in the transmission coefficient. For changes in the wavelength of the selected cladding mode, the accuracy is 0.3203 mm, with the input light polarization being changed in the range from 0° (P type) to 90° (S type).
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.
Non-measured points (NMPs) are one of vital problems in optical measurement. The number and location of NMPs affect the obtained surface texture parameters. Therefore, systematic studying of the NMP is meaningful in understanding the instrument performance and optimizing measurement strategies. This paper investigates the influence of measurement settings on the non-measured points ratio (NMPR) using structured illumination microscopy. It is found that using a low magnification lens, high exposure time, high dynamic range (HDR) lighting levels, and low vertical scanning interval may help reduce the NMPR. In addition, an improved approach is proposed to analyze the influence of NMP on areal surface texture parameters. The analysis indicates that the influence of NMP on some parameters cannot be ignored, especially for extreme height parameters and feature parameters.
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).
The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang Province Key Laboratory of Advanced Manufacturing Technology, Zhejiang University, 310027, Hangzhou, China
The authors update the issue disassembly-free control and correction of all components of the error of measuring channels with multi-bit analog-to-digital converters (ADCs). The main disadvantages of existing methods for automatic control of the parameters of multi-bit ADCs, in particular their nonlinearity, are identified. Methods for minimizing instrumental errors and errors caused by limited internal resistances of closed switches, input and output resistances of active elements are investigated. The structures of devices for determining the multiplicative and nonlinear components of the error of multi-bit ADCs based on resistive dividers built on single-nominal resistors are proposed and analyzed. The authors propose a method for the correction of additive, multiplicative and nonlinear components of the error at each of the specified points of the conversion range during non-disassembly control of the ADC with both types of inputs. The possibility of non-disassembly control, as well as correction of multiplicative and nonlinear components of the error of multi-bit ADCs in the entire range of conversion during their on-site control is proven. ADC error correction procedures are proposed. These procedures are practically invariant to the non-informative parameters of active structures with resistive dividers composed of single-nominal resistors. In the article the prospects of practical implementation of the method of error correction during non-dismantling control of ADC parameters using the possibilities provided by modern microelectronic components are shown. The ways to minimize errors are proposed and the requirements to the choice of element parameters for the implementation of the proposed technical solutions are given. It is proved that the proposed structure can be used for non-disassembly control of multiplicative and nonlinear components of the error of precision instrumentation amplifiers.
A novel measurement method and a brief discussion of basic characteristics of measuring the phase shift angle between two sinusoidal signals of the same frequency are presented in this paper. It contains a mathematical model for using conditional averaging of a delayed signal interfered with noise to measure the phase shift angle. It also provides characteristics of conditional mean values and discusses the effect of random interferences on the accuracy of the phase shift measurement. The way to determine the variance of the conditional mean value, together with the assessment of standard and expanded uncertainty, are described. The uncertainty characteristic shows the complementary properties of the discussed angle measurement principle �� for small absolute values |��| (minimum for �� = 0) relative to the correlation principle, where the minimum measurement uncertainty is present for �� = ��/2. |
Rzeszow University of Technology, Faculty of Electrical and Computer Engineering, Department of Metrology and Diagnostic Systems, W. Pola 2, 35-959 Rzeszow, Poland
At the National Institute of Metrological Research (INRIM) an evaluation of a commercial dual source high resistance bridge has been performed. Its two main measurement modes (single measurements and multiple measurements) have been investigated. The best settle time of a 10:1 measurement of high resistance ratio has been estimated to be about three times the time constant of the circuit involving the resistors. This constant, in turn, depends on the highest value resistor. By means of mathematical estimators, suitable numbers of the readings of the detector have been established in order to minimize noises. A compatibility test at 100 TΩ has shown that the best precision of the commercial bridge is achieved utilizing the multiple measurements mode with the auto update function. This mode also allows the characterization of a resistor as a function of the settle time. This characterization can be useful for the owner of the resistor who can request the laboratory to perform the calibration of the resistor with the settle time which is necessary for him.
Ophiuroids from the Upper Jurassic marine deposits (upper Oxfordian–lower Kimmeridgian) of southern and north-western Poland have been studied in two sections: Zalas quarry in the Kraków-Częstochowa Upland in southern Poland and Wapienno/Bielawy quarries in the Kuyavia region of north-western Poland. Described herein are nine taxa belonging to five genera (one new to science): Alternacantha Thuy and Meyer, 2013; Dermocoma Hess, 1964; Ophiobartia Loba gen. nov.; Ophioderma Müller and Troschel, 1840; Ophiotreta Verrill, 1899, and three families: Ophiacanthidae and Ophiodermatidae (both of Ljungman, 1867), and Ophiotomidae Paterson, 1985. Only a few representatives of some of these taxa have previously been reported from the Jurassic of Poland. One species, Ophiobartia radwanskii Loba, is established as new. The ophiuroid material recognized from both Polish localities is close to those described from Western Europe at family or even genus level. Both studied ophiuroid assemblages from Zalas and Wapienno/Bielawy show similarities, being dominated by the cosmopolitan species Ophioderma spectabile Hess, 1966, and by different species of Dermocoma. The recognized ophiuroid assemblages represent a rather shallow-water environment.
This paper is a summary of the results of research on the accumulation conditions of the Upper Younger Loess (LMg) in Poland and Bug loess (bg) in Ukraine from the maximum stage (MIS 2) of the Vistulian (Weichselian) Glaciation in central and eastern Europe. These studies included an analysis of the morphological (topographic) situation of the loess cover, its grain size and heavy mineral composition, the preserved structures of loess sedimentation as well as mollusc and pollen analyses of this loess. They revealed that the accumulation of Upper Younger Loess (UYL) might have been more dependent on the prevailing moisture conditions than previously thought. These conditions could have been caused by cold air masses from an ice sheet and warm air masses from the Mediterranean Sea and Atlantic coming together in the Carpathians and the Holy Cross Mountains and favouring the formation of dust storms and precipitation. In this process, a loading of loess dust (formed from local rocks weathering in periglacial conditions) by atmospheric moisture particles was especially significant. The moist substrate not only favoured the periodic development of vegetation and molluscs but also enabled the interception of dust and the accumulation of an increasingly thick loess cover. Westerly and south-westerly winds predominated in the UYL as indicated by the topographic position of loess patches and the mineral composition of the studied loess. Periodically an increased air circulation from the east and northeast occurred.
In the mining galleries of the abandoned Au-As mine in Radzimowice, diverse groups of secondary arsenates crystallized recently. They form several characteristic assemblages. In the first of them the typical minerals are bukovskýite and melanterite. The second group of secondary arsenates includes scorodite, kaňkite, zýkaite, and pitticite. The third assemblage includes Co-Ni-Mg arsenates of the erythrite-annabergite-hörnesite series. The first assemblage crystallized in a zone with a very high activity of sulphate and arsenate ions and where the pH varies within a narrow range of 2.0–3.5. The second group of secondary arsenates formed in the acidic zone. The minerals identified here suggest pH variation within fairly wide ranges, from about 2.0 to 5.5. Contrary to the first and second mineral assemblage, the Co-Ni-Mg arsenates formed under different geochemical conditions. Their crystallization took place under weak acidic to neutral conditions.
Twenty silver minerals of the sulphide, arsenide, selenide, telluride, sulphosalt and chloride groups were found in 13 locations in the Variscan Karkonosze granitoid pluton. Previously only one of these minerals was known from this area. The findings include species characterized in publications as rare or exceptionally rare, e.g., muthmannite and tsnigriite. They occur in pegmatites and quartz veins; their parageneses are described. The studies include determination of chemical compositions, formulae calculations and recording of XRD patterns. Inclusion studies in paragenetic quartz indicate that they crystallized from epithermal fluids with a common but low component of CO 2. The results suggest that the minerals formed from trace elements (Ag included) in the Karkonosze granitoid due to very local degrees of recrystallization of the host granitoid.
The contributions of the members of the Department of Geochemistry, Mineralogy and Petrology, University of Warsaw, to the study of the chevkinite-group of minerals (CGM) are described. The range of research topics includes: (i) geochemical and mineralogical studies of natural occurrences of the group, and attempts to relate their chemical composition to host lithology; (ii) detailed analysis of the hydrothermal alteration of CGM in various settings, with the aim of understanding element redistribution and the potential implications for ore formation. An ongoing series of high P-T experiments is providing quantitative information on the pressures, temperatures and melt water conditions under which the alteration assemblages have formed. Various spectroscopic techniques are being used to determine the structure of the CGM and to identify cation distribution in the structures.
The Northern Copper Belt is located in south-western Poland, a region well known for its copper and silver occurrences of varying significance. This area also includes the abandoned mines of the North-Sudetic Trough (Old Copper District), as well as the currently active New Copper District in the southern part of the Fore- Sudetic Monocline. The vast exploration programme of Miedzi Copper Corp. initiated in 2011 in the northern, deeper part of the Fore Sudetic Monocline provided new data about the deeper parts of this geological unit, located north of the known deposits. A number of prospective areas with Cu-Ag mineralization were investigated, which ultimately resulted in the discovery of three new Cu-Ag deposits. Both the prospective areas and the documented deposits form the so-called Northern Copper Belt, which as a whole has high potential for the identification of new ore deposits and an increase in resources. A description of these three new deposits is provided along with characteristics of the areas of their possible extension, and the additional prospective areas with hypothetical and speculative resources. The new deposits are compared to other Polish Cu-Ag ore deposits, with an emphasis on differences in their geological structure and mineralogy. The paper also presents a brief summary of the applied new exploration tools which have led to this discovery.
The presented studies focus on changes in groundwater levels and chemistry, and the identification of important factors influencing these changes on short- and long-term scales in urban areas. The results may be useful for rational and sustainable groundwater planning and management in cities. The studies concerned three aquifers: (1) the shallow Quaternary aquifer, (2) the deep Quaternary aquifer, and (3) the Oligocene aquifer in the capital city of Warsaw (Poland). The spatial variability of groundwater recharge was determined and its changes in time were characterized. The characteristics of groundwater levels were based on long-term monitoring series. The results indicate that urban development has caused overall reduction in infiltration recharge (from 54 to 51 mm/ year), which is particularly clear in the city suburbs and in its centre, where land development has significantly densified during the last 30 years. Studies of groundwater levels indicate variable long-term trends. However, for the shallowest aquifer, the trends indicate a gradual decrease of the groundwater levels. In the case of the much deeper Oligocene aquifer, groundwater table rise is observed since the 1970s (averagely c. 20 m), which is related with excessive pumping. Based on the studied results, the groundwater chemistry in the subsurface aquifer indicates strong anthropogenic influence, which is reflected in multi-ionic hydrogeochemical types and the occurrence of chemical tracers typical of human activity. The Oligocene aquifer is characterized by a chemical composition indicating the influence of geogenic factors.
Geochemical studies of CO2-rich therapeutic waters in the Sudetes have provided new data on a wide range of trace elements, going beyond standard chemical analyses of such waters. A consistent set of physicochemical data obtained using the same analytical methods was subjected to statistical analyses, including hierarchical clustering, factor analysis and nonparametric tests (Kruskal-Wallis, Tau Kendall), to reveal geochemical relationships between physicochemical and chemical parameters in the waters, and their relationships with the aquifer lithology. Distinct differences in the composition of waters found in crystalline rocks (mainly gneisses and mica schists) and sedimentary rocks were identified. The wide range of elements can be associated with the hydrolysis of silicate minerals, including alkali and alkali earth metals (Li, Na, K, Rb, Cs, Be) and (mostly) transition elements (Fe, Mn, Zn, Co, W, Mg). Carbonate equilibria are the next important factor as it determines the aggressiveness of the water towards the minerals of aquifer rocks and affects the concentrations of numerous solutes. The probable common origin of chlorides, bromides and sulphates together with Li, Na, Sr may be related to the relict saline component of deep circulating waters, a hypothesis that requires further investigations.
Petroleum products influence the engineering behaviour of the soil. Neogene clays and glacial tills from Central Poland were tested under laboratory conditions to evaluate the changes of selected physical and mechanical parameters: particle size distribution, particle density, swelling, shear strength and permeability. Four petroleum products were used in the experiments: diesel fuel, kerosene, jet fuel and mineral engine oil. The study revealed that even for the lowest degree of contamination the values of physical and mechanical properties of the soils changed significantly. Greater variation can be expected in soils contaminated with high-viscosity compounds. Also, higher relative changes were found for glacial tills than for Neogene clays. Consolidation tests revealed changes in soil permeability depending on the soil composition and the physical properties of the contaminant – considerable reduction of permeability was observed for glacial tills contaminated with light Jet fuel, while the reduction was lower for Neogene clays. The obtained results indicate the role of mesopores and the dimensionless pore pressure coefficient in changes of soil permeability. The methodological issues regarding testing and analysing the hydrocarbon-contaminated soils were also presented and discussed, which might be useful for researchers studying contaminated soils.
Engineering activity may lead to uncontrolled changes in the geological environment. This paper presents an example of structural changes in fluvial sand of the Praski terrace (in Warsaw) caused by the activity of a temporary concrete batching plant. Our investigations made it possible to identify the material responsible for the structural anomalies observed in the bottom of the trench excavation. The compound responsible for the cementation phenomenon was identified as ettringite – hydrated calcium aluminosulphate: Ca 6Al 2[(OH) 12(SO 4) 3]·26H 2O. The source of ettringite were most probably significant volumes of contaminants coming from the temporary concrete batching plant (e.g., from the rinsing of concrete mixers and/or installations for concrete storage and transportation). While penetrating into the ground, ettringite caused extensive cementation of the soil mass, mainly in the saturation zone. As a result, the mineral (chemical) composition of the inter-grain space changed and the structure of the sand was strengthened. The estimated zone of volumetric changes in soil properties was about 6 thousand m 3. However, analysis of the chemical composition of groundwater for its potential sulphate contamination, did not reveal any anomalous concentrations of sulphates.
Research related to photovoltaic panels comprises different topics starting with modelling solar cells, finding new maximum power point tracking (MPPT) algorithms, testing existing ones or designing of DC/DC converters for MPPT systems and microgrids that incorporate photovoltaic energy sources. In each of the examples above a deep knowledge of photovoltaic panels is required, as well as a reliable measurement system that can deliver continuous, stable light with enough power to meet standard test conditions (STC) and that can ensure repeatable results. Therefore this paper presents a low-cost solar simulator with a microcontroller-based measurement system, that can be used for various measurements of low-power photovoltaic panels.
en
pl
