Measurement of tool wear using a non-contact method, using a laser measuring system

Measurement of tool wear using a non-contact method, using a laser measuring system. This article examined the tools - straight cutters with a contactless method using a laser sensor. The first aspect of the research was to determine the influence of the spindle rotational speed on the accuracy of laser measurement. The second aspect of the research was to establish the correlation between the diameter of the tool measured with a laser micrometer and the wear of the tool measured with the microscope. A good (R2> 0.8) Pearson's correlation was found between the measured tool diameter and it’s wear.

Wi-CAS: A Contactless Method for Continuous Indoor Human Activity Sensing Using Wi-Fi Devices

With the new coronavirus raging around the world, home isolation has become an effective way to interrupt the spread of the virus. Effective monitoring of people in home isolation has also become a pressing issue. However, the large number of isolated people and the privatized isolated spaces pose challenges for traditional sensing techniques. Ubiquitous Wi-Fi offers new ideas for sensing people indoors. Advantages such as low cost, wide deployment, and high privacy make indoor human activity sensing technology based on Wi-Fi signals increasingly used. Therefore, this paper proposes a contactless indoor person continuous activity sensing method based on Wi-Fi signal Wi-CAS. The method allows for the sensing of continuous movements of home isolated persons. Wi-CAS designs an ensemble classification method based on Hierarchical Clustering (HEC) for the classification of different actions, which effectively improves the action classification accuracy while reducing the processing time. We have conducted extensive experimental evaluations in real home environments. By recording the activities of different people throughout the day, Wi-CAS is very sensitive to unusual activities of people and also has a combined activity recognition rate of 94.3%. The experimental results show that our proposed method provides a low-cost and highly robust solution for supervising the activities of home isolates.

Innovative electrical engineering developed for the transport industry by the Emperor Alexander I Petersburg State Transport University

Objective: To familiarize the general scientific community with the latest electrotechnical innovative developments for the transport industry, carried out by the scientists of the Emperor Alexander I Petersburg State Transport University in the period from 2000 to 2021. Methods: We used the methods of calculation of electromagnetic fields and circuits, mathematical analysis, mathematical physics and numerical methods in the development of the described devices and systems. Results: 101 We developed a pipeline high-speed magnetolevitation transport system with vehicle movement in a rarefied atmosphere, a series of pantograph pantographs for heavy-loaded and high-speed trains using solid lubricants and a contactless method of transmitting electrical energy, a plasma device for fine cleaning of circuit boards for microcircuits, a device for creating a comfortable climate in office premises, electrohydroimpulse installations designed for loosening frozen coal in gondola cars in winter, shock tests of wagons, escalators and travalators using linear electric motors, high-speed electric switches-breakers, heat generators based on an electromechanical converter with the functions of a heater and pump, a wagon generator with a forced excitation system, a pulse voltage generator, allowing to measure the pulse resistance of the grounding conductors of the contact network supports, a complex of installations for various purposes using ozone technologies, a system for laser monitoring of the integrity of tanks, a device for diagnosing the degree of corrosion of the fittings of contact supports, an electrohydroimpulse installation for impact welding, treatment plants, technology for recycling car tires, security systems of the main trackbed. Practical importance: The use of the described developments will increase energy efficiency, energy saving and safety of production processes in transport

Model Investigations of Scouring at the Hričov Weir Using Short-Range Photogrammetry

Stilling basins are commonly used to efficiently dissipate energy of flow at weirs. Different types of stilling basins are used at weirs due to different conditions – hydraulic, operational, constructional. At the Hričov water structure a short stilling basin has been built. Its operation over the years showed that it does not dissipate the energy of the flowing water sufficiently, which causes intense scouring in the riverbed downstream. To partially deal with this problem and to protect the riverbed from scours, a rockfill embankment supported with a steel construction was constructed adjacent to the stilling basin’s toe. Despite this riverbed fortification, scours are being created in the riverbed and even in the fortification itself for different cases of operation conditions of the weir. A hydraulic research on a scaled model of the weir was used to investigate the problem and to propose a permanent solution significantly improving the scouring downstream the weir. The proposed fortification of the riverbed downstream the weir was tested at different operational conditions, which simulated extreme situations at the weir. To assess the effects of the investigated fortification, the simulations were performed for the weir without and with the fortification. After each simulation, the deformations in the riverbed (scours) were measured and evaluated. For measuring the riverbed deformations on the model, the method of short-range photogrammetry was used as a very effective and contactless method. This method allowed to examine the investigated area with a very high accuracy and speed. Digital models of the riverbed deformations created after each simulation on the hydraulic model were used to determine the locations and sizes of the deepest scours. Final assessment of the results showed the improvement in the reduction of scouring by the proposed fortification by almost 50% in the size of the scours. The investigations and the results are described in this paper.

A Contactless Method for Measuring Full-Day, Naturalistic Motor Behavior Using Wearable Inertial Sensors

How can researchers best measure infants' motor experiences in the home? Body position—whether infants are held, supine, prone, sitting, or upright—is an important developmental experience. However, the standard way of measuring infant body position, video recording by an experimenter in the home, can only capture short instances, may bias measurements, and conflicts with physical distancing guidelines resulting from the COVID-19 pandemic. Here, we introduce and validate an alternative method that uses machine learning algorithms to classify infants' body position from a set of wearable inertial sensors. A laboratory study of 15 infants demonstrated that the method was sufficiently accurate to measure individual differences in the time that infants spent in each body position. Two case studies showed the feasibility of applying this method to testing infants in the home using a contactless equipment drop-off procedure.

Differential Inductive Sensing System for Truly Contactless Measuring of Liquids’ Electromagnetic Properties in Tubing

Certain applications require a contactless measurement to eliminate the risk of sensor-induced sample contamination. Examples can be found in chemical process control, biotechnology or medical technology. For instance, in critically ill patients requiring renal replacement therapy, continuous in-line monitoring of blood conductivity as a measure for sodium should be considered. A differential inductive sensing system based on a differential transformer using a specific flow chamber has already proven suitable for this application. However, since the blood in renal replacement therapy is carried in plastic tubing, a direct measurement through the tubing offers a contactless method. Therefore, in this work we present a differential transformer for measuring directly through electrically non-conductive tubing by winding the tube around the ferrite core of the transformer. Here, the dependence of the winding type and the number of turns of the tubing on the sensitivity has been analyzed by using a mathematical model, simulations and experimental validation. A maximum sensitivity of 364.9 mV/mol/L is measured for radial winding around the core. A longitudinal winding turns out to be less effective with 92.8 mV/mol/L. However, the findings prove the ability to use the differential transformer as a truly contactless sensing system.

Assessment of the Online Teaching mode in the Subject of Geography at Undergraduate Level from Student's Perspective during the Academic Year 2020-21 : A Case Study

The COVID-19 is an ongoing global pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The virus was first identified in December 2019 in Wuhan, China. The COVID-19 pandemic in 2020 resulted in the abrupt shutting of all the educational institutions (schools, colleges, and universities) in India. This resulted in dramatic changes in the education system with the distinctive rise of e-learning, whereby teaching is undertaken remotely and on digital platforms. Online learning is a competent and contactless method of teaching to remotely located students. Geography is a branch of science which deals with the study of the earth’s surface and the relationships between people and their environment. Geographers explore both the physical properties of the earth’s surface and the human societies spread across it. The subject matter of Geography containing different theory papers and practical papers cannot just be effectively taught in a classroom or laboratory but best enlightened on the field. For the effective learning process in the subject of Geography, students require on-ground observations, laboratory analysis, projects and dissertations, field surveying, computer mapping and analysis, field trips and excursions, etc. It helps the budding Geographers to acquire not only theoretical knowledge but also practical skills. But the COVID-19 pandemic situation confronted the education system, forcing the educators in the field of Geography to shift to an online mode of teaching, leaving them with no option. During this crisis, the educators have given their best in teaching the subject matter of Geography to the students by using various open-source teaching aids by overcoming the issues like lack of training and professional technical support. This altered the traditional teaching and learning process in the field of Geography, which essentially affects the students of Geography. Thus, a case study was undertaken to assess the online teaching in the subject of Geography at the undergraduate level during the academic year 2020-21 from the student’s perspective.

Curing Assessment of Concrete with Hyperspectral Imaging

The curing of concrete significantly influences the hydration process and its strength development. Inadequate curing leads to a loss of quality and has a negative effect on the durability of the concrete. Usually, the effects are not noticed until years later, when the first damage to the structure occurs because of the poor concrete quality. This paper presents a non-destructive measurement method for the determination of the curing quality of young concrete. Hyperspectral imaging in the near infrared is a contactless method that provides information about material properties in an electromagnetic wavelength range that cannot be seen with the human eye. Laboratory tests were carried out with samples with three different curing types at the age of 1, 7, and 27 days. The results showed that differences in the near infrared spectral signatures can be determined depending on the age of the concrete and the type of curing. The data was classified and analyzed by evaluating the results using k-means clustering. This method showed a high level of reliability for the differentiation between the different curing types and concrete ages. A recommendation for hyperspectral measurement and the evaluation of the curing quality of concrete could be made.

Measurement Assurance of Additive Manufacturing on the Example of Laser Surface Polishing Products by Remelting

The article presents the results of studies of the surfaces of parts processed by the contactless method of laser polishing. The results of technological surface treatment using a laser technological complex based on an ytterbium fibre laser with a power of 5 kW are presented. The results of studies of the surface roughness of the samples after laser treatment, including the non-uniform character due to the redistribution of the liquid metal melt over the surface, are shown. Requirements for metrological support of additive technology have been developed using the example of the process of laser remelting in order to improve quality and further automation.

Research on the Influence of Production Technologies on the Positioning Accuracy of a Robotic Arm for Low-Handling Weights

The subject of the paper is the research of production technologies’ influence on positioning accuracy of a robotic arm. The aim was to find out whether different production technologies (additive and conventional) and the related design differences of the robotic arm affect its operational functionality. In the research, positioning accuracy of a robotic arm formed by three partial arms was specifically investigated, while the first partial arm, Arm I, was manufactured by two different technologies. On the robotic arm, the research was carried out in such a way that the first partial arm, Arm I, was being continuously changed and was available for research purposes in two variants. Each of the Arm I variants was manufactured using a different technology (additive and conventional) while, at the same time, the individual variants also differed in construction. The design differences of both variants were related to the production technology used. The measurement of positioning accuracy was performed with the use of two methods. Specifically, a contact and a non-contact method were used. The contact method was implemented on a 3D-measuring machine, RAPID, and the second contactless method was performed using an inductive sensor.