Journal of Mechatronics and Artificial Intelligence in Engineering
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Fault identification and remaining useful life prediction of bearings using Poincare maps, fast Fourier transform and convolutional neural networks
Get PDFBearings are integral components of rotating machinery and their failure tends to be a catastrophic failure of the machine. Poincare Maps are used to detect bearing failures using the concept of non-linear dynamics. Each time-domain vibration signature array has its own Poincare Map over a period of time. Fast Fourier Transform (FFT) is a method of analysing the frequency plots of a bearing signature. Convolutional Neural Networks (CNN) process the bearing Continuous Wavelet Transform images and provide the Remaining Useful Life (RUL) of the bearing. The Poincare Maps and FFT plots are used to diagnose the type and location of the fault in the bearing, whereas the CNN helps to provide the fraction of Remaining Useful Life. The study concludes that a combination of Poincare Maps, FFT analysis and Convolutional Neural Networks constitutes a robust and precise method of monitoring bearing conditions
Utilization of low-potential secondary energy resources at oil pumping station
Get PDFThe article considers the sources of low-potential heat at oil pumping station, estimates the amount of heat of technological processes that is irretrievably lost in the environment from the oil ACD, cooling systems of electric motors and wastewater treatment plants, and also presents possible ways of utilization and useful use of this heat using heat pumps
Design of highly reflective film for smart radiation device
Get PDFSmart radiation device (SRD) based on the asymmetrical Fabry-Perot cavity automatically tune its IR emittance depending on the ambient temperature, making it an ideal choice for thermal control system of spacecrafts. The low solar absorption is desirable for SRD to prevent the spacecraft from overheating by sun light. In this paper, a multilayer highly reflective film with LHk stacking layers is designed to reduce the solar absorptance (As) of the Ag/Al2O3/VO2 structured SRD. The reflective film achieves a high reflection band in ~220 nm bandwidth from 460 nm to 680 nm, which results in a reduction of the solar absorptance by 25.56 % for SRD working at low temperature and 24.27 % at high temperature as the stacking factor k= 5. The simulation results indicate that an economic reflective film with k= 3 can achieve effective suppression of As of SRD, demonstrating the promising potential of the proposed reflective film in thermal control application of spacecrafts
Correlation between ST-elevation myocardial infarction, non-ST-elevation myocardial infarction and the local Earth’s magnetic field changes
Get PDFStronger oscillations in the local Earth magnetic field may have an impact on the course of ischemic heart disease. This effect is individual for every person and depends on the sex, age, living territory, season, capability to adjust to magnetic field fluctuations and health status. Individuals who already have cardiovascular disease are more sensitive to magnetic field fluctuations, therefore further research is needed to make conclusions. Aim: To identify correlations between changes in local Earth magnetic field frequencies and patients with ST segment elevation myocardial infarction (STEMI) and non-ST segment elevation myocardial infarction (NSTEMI) cases per week, cases by sex per week and patients’ blood laboratory parameters (low-density lipoprotein cholesterol and Troponin I level). Methods: A retrospective study of 1667 patients, who were admitted to the Hospital of Lithuanian University of Health Sciences Kaunas Clinics between 1st January and 31st December 2019 due to acute coronary syndrome (STEMI and NSTEMI), were included in the study. Local Earth's time varying magnetic field (TVMF) was measured by a magnetometer located in Baisogala, Lithuania. Data from the magnetometer was collected daily, and weekly averaged. We assessed the correlations between average weekly geomagnetic field strength in six different frequency ranges (Hz) and average number of STEMI and NSTEMI cases per week, cases by sex per week and patients’ blood laboratory parameters (low-density lipoprotein cholesterol and Troponin I level). Results: The presence of a stronger magnetic field in the frequency range of 32-65 Hz was significantly related to the number of cases in the STEMI group during the winter season (r= 0.583, p= 0.036). Tendency towards a positive correlation was found during the winter in the men's group with STEMI in the high frequency range of 32-65 Hz. Low-density lipoprotein cholesterol level correlated positively in the winter STEMI group with the magnetic field in the 32-65 Hz range, and in the autumn STEMI group with the magnetic field in the frequency range of 0-7 Hz. Conclusion: Increased geomagnetic field strength in the high frequency range of 32-65 Hz is associated with a higher number of cases in the STEMI group
Is jaw functional orthopedics an efficient tool to treat anterior open bite? A retrospective study
Get PDFAnterior Open Bite (AOB) is a malocclusion for which the choice of a treatment protocol it is challenging. There are some protocols that have been shown to be effective for open bite treatment. The aim of this investigation was to study the behavior of overbite during AOB treatment with Jaw Functional Orthopedics (JFO). The behavior of overbite was studied retrospectively in 17 patients treated in the Specialization Course in (JFO – ABO Muriaé (Muriaé, MG Brazil). Monthly overbite measurements in millimeters were taken with a pachymeter and the data were stored in an individual paper worksheet. Data obtained before functional appliance installation (T0) and after 12-months of treatment (T1) were compared. Wilcoxon non-parametric test for 2 paired samples was use for statical treatment of the data. P= 0.003 for overbite comparison T1-T0. It could be concluded that Functional orthopedic appliance has shown to be an effective tool for treating anterior open bite in the sample studied. Further studies, mainly Randomized Clinical Trials, with larger samples are necessary to confirm this result and to study stability and skeletal behavior in anterior open bite treated with Jaw Functional orthopedics
Comprehensive sensitivity analysis on static and dynamic reservoir parameters impacting near wellbore injectivity during CO2 sequestration
Get PDFCarbon capture and storage (CCS) is proved to be effective measure for reducing CO2 emissions. whilst the world still highly depends on the use of fossil fuel energy, this method is necessary for reaching the world’s 1.5 °C goal. In CCS, CO2 is hindered from entering the atmosphere by capturing it from sources of emission and storing it in geological formation. Saline aquifers among all possible underground formations are most common targeted ones for CO2 storage due to their frequent presence, and large storage capacity. However, this storage option suffers from sufficient well injectivity to inject large volumes of CO2 at acceptable rates through a minimum number of wells. The injectivity impairment / reinforcement happens through mineral dissolution, fine particle movement, salt precipitation and hydrate formation (known so far). Each of these mechanisms will be more dominant in injectivity alteration at different distance from the injection point depending on reservoir pressure and temperature, formation water salinity, rock mineralogy, and flow rate of CO2 injection as well as its dryness. Incorporating all the finding into radial flow near wellbore will help gaining insight into the resultant of injectivity changes over time and distant from injection point. In this study we have chosen Eclipse 300 together with an open-source code to investigate the impact of formation characteristics, CO2 -Brine-Rock interaction, pressure, temperature as well as injection rate on injectivity alteration. The goal for this work is to provide a workflow which can help predicting injectivity alteration using the existing tools. Simulation results show that the high homogenous horizontal permeability in combination with vertical flow baffles in the formation (among all other parameters) has positive impact on storage capacity by increasing residual trapping. However, permeability is affected severely by salt precipitation during CO2 injection. Combined static and dynamic parameter study demonstrate that the injection rate plays a crucial role in size and expansion of CO2 plume as well as growth rate of dry out zone length, amount of salt precipitation and length of equilibrium region. The higher the injection rate, the quicker activation of the capillary and gravity force which leads to drag more brine to near well-bore resulting in higher volume fraction of salt precipitation. However, low injection rate could result in smaller CO2 plume, shorter dry out zone and longer equilibrium region in term of distance from injection point
New CO2 and Hydrogen storage site marketing: How to make your storage site unique and attractive?
Get PDFToday we met the situation, when our knowledge and expertise are far away from marketing – an ability to sell our knowledge to the end-user (public, policymakers, governments, and small and big enterprises). This study aimed to attract stakeholders by proposing new techno-ecological synergy concept of geological storage of CO2 (CGS) and hydrogen (UHS) in a cost-competitive, self-supporting storage site. The “story of success” of the offshore geological structure E6 in Latvia has started from an invisible point on the European map, oil-bearing but not very promising geological structure to the unique and one of the best cost-competitive, self-supporting, conceptual techno-ecological examples of a possible synergy of storage concepts with renewables energies. Using detailed petrophysical, mineralogical and geochemical analyses of the Cambrian Series 3 Deimena Formation reservoir sandstones in this structure, the CO2 storage capacity was estimated with different levels of reliability from a conservative 158 Mt (106-252 Mt) up to an average optimistic average of 396 Mt (264-631 Mt). The theoretical CO2 storage capacity in the oil-bearing limestones of the Upper Ordovician Saldus Formation was estimated at the end of the Enhanced Oil Recovery cycle using the CO2 (CO2-EOR) as an average of 110 Mt (65-144 Mt). The E6 structure was estimated as the most prospective and the largest for CO2 geological storage in the Baltic Region with a total average CO2 storage capacity of about 500 Mt. Time-lapse numerical seismic modelling was applied to analyze the feasibility of CO2 storage monitoring in the E6. The novelty of this approach was the coupling of the chemically induced petrophysical alteration effect of CO2-hosting rocks, measured in the laboratory during the CO2 injection-like experiment, with time-lapse numerical seismic modelling. According to changes in the amplitude and two-way travel times in the presence of CO2, reflection seismic could detect CO2 injected into the deep aquifer formations even with low CO2 saturation values. Our results showed the effectiveness of the implemented time-lapse rock physics and seismic methods in the monitoring of the CO2 plume evolution and migration in the E6. The new concept of techno-ecological synergy of the CCUS project with different eco-friendly renewable energy recovery technologies, which support circular economy targets, is presented. The concept of the CCUS project includes six innovative elements of techno-ecological synergy: (1) CGS, (2) Geothermal energy recovery during CO2 geological storage (CPG), (3) CO2-EOR, (4) underground hydrogen storage (UHS), (5) solar energy and (6) wind energy recovery. This concept should maximise efficiency, minimize the carbon footprint of the full-chain CCUS process and demonstrate the “winx” situation (where “x” is a number of additional benefits of the project). We demonstrated an example of the project supporting also a win5 global situation (that is, a win-win scenario with a minimum of five potential global outcomes): greenhouse gas emissions (GHGE) reduction, (2) economic profitability, (3) increased CO2 storage capacity, (4) public acceptance and (5) retargeting of oil and gas businesses. Small wind offshore floating plant installed around the rig and solar panels covering free surfaces of the rig and a compact geothermal plant using CO2 (20 times smaller than a conventional plant) will produce renewable energy added to the project electricity net to cover the energy needs of the project. The excess energy will be used by compact hydrogen production plant established directly on the rig. The produced hydrogen could be stored underground and when needed, transported by ship to the port. For the first time, we estimated hydrogen storage capacity in the E6-B, the smaller compartment of the E6 offshore structure as 30 Kt. This scenario is a basis for the new concept of CO2 and hydrogen storage site marketing: how to retarget fossil fuel business (the depleted oil and gas fields) into the storage-targeted and renewable energy business, permitted to achieve the carbon-free energy transition using principles of circular economy and sustainable use of resources and environment
Techno-economic modelling of the Baltic CCUS onshore scenario
Get PDFTechno-economic modelling of the Baltic onshore CO2 transport, storage, and utilization scenario included HeidelberCement-owned Kunda Nordic Cement (KNC) plant, the main Estonian cement producer, four Estonian and one Latvian power plant and CO2 mineral carbonation of the oil shale ash, as possible CO2 use option. In 2019 nearly 6.5 Mt of oil shale ash (OSA) was produced in Estonia from energy production. Estonian OSA could be used as an effective sorbent in the proposed CO2-mineralization process, using CO2 from flue gas and producing precipitated CaCO3 (PCC) of high quality. Mineral carbonation of 0.42 Mt CO2 using 3.8 Mt of fresh OSA and about 6.33 Mt CO2 produced annually by five Estonian and one Latvian plant transported by pipeline for storage into the North-Blidene structure in western Latvia are combined in the CCUS scenario. Cambrian Deimena Formation reservoir sandstone is located at the depth of 1035-1150 m in the selected saline aquifer. The average optimistic storage capacity of about 270 Mt allows planning CCUS project for 30 years. The share of the Estonian emissions avoided and stored in Latvia is 86.5 %, including 8.2 % by KNC, while Latvian stored emissions will compose 13.5 %. Annually 6.8 Mt CO2 could be captured, transported and injected, including 6 Mt CO2 avoided using transport and storage and 0.42 Mt CO2 avoided using MC of Estonian OSA. During 30 years nearly 204 Mt CO2 will be captured, used and stored, while 193 Mt CO2 could be avoided. The total average transport and storage (T&S) cost of the scenario is 18.4 €/t CO2 injected. This cost depends on the transport distance, according to the applied methodology, and it is the most expensive for the Eesti Energia PPs. The lowest T&S cost of 5.54 €/t CO2 injected will have Latvenergo TEC-2 PP located at a smaller distance from the storage site. At the price of EEAP (CO2 Emission Allowance Price in EU ETS) of 40 €/t CO2 and 50 €/t PCC, the CCUS scenario could be beneficial for three Eesti Energia and Latvenergo TEC-2 power plants. For the KNC and VKG Energia plants without CO2 use options, the higher EEAP of about 48-50 €/t CO2 is needed to cover all CCUS costs including capture, compression, transport, storage and monitoring. The transport and storage costs are distance-dependent, as pipelines are the most expensive part of the transport, storage and monitoring costs. At the present EEAP of about 90 €/t CO2, all the participating plants will get benefits from the proposed scenario. This study is supported by CLEANKER project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement n. 764816
Analysis of vibration characteristics of rotating parallel flexible manipulator considering joint elastic constraints
Get PDFThe bolt joint is the key component connecting the rigid moving base body and the flexible manipulator. The dynamic characteristics of the flexible manipulator under the elastic constraint of the joint are analyzed, and the action mechanism of the elastic constraint of the bolt joint on the frequency and vibration mode is revealed. Considering the effects of line constraint and torsion constraint, the elastic constraint model of the joint is established. Based on the principle of virtual work, the boundary constraints of the joint end and the free end are established, and the analytical equation of frequency and the expression of vibration mode function are derived. The first three frequencies and vibration mode characteristics of the flexible manipulator under elastic constraints are analyzed numerically. The sensitivity method is used to analyze the effect of linear constraints and torsional constraints on the frequency, and the elastic constraint region is established to characterize the functional relationship between the binding stiffness and the natural frequency. It is found that under elastic constraints, the influence of torsional stiffness of bolt joint is mainly concentrated in the low-order modal frequency, while the linear stiffness has a great influence on each order modal frequency of the manipulator; With the decrease of elastic constraint stiffness, its influence on modal shapes gradually increases, especially on high-order modal shapes. The research results prove the internal mechanism of the influence of elastic constraints on vibration characteristics, which provide a theoretical basis for improving the dynamic characteristics of flexible manipulator
Repetitive impacts recovering using variational mode extraction with constructed reference enhanced by improved blind deconvolution
Get PDFThe impulse and modulation characteristic of rolling bearing’ faulty signal is often very weak when early fault arises in rolling bearing or gears, and the main reasons are due to the signal attenuation caused by too long signal acquisition path and the interference of other multi-source vibration. In order to extract the weak feature accurately, a method named as variational mode extraction (VME) based on constructed reference enhanced by improved minimum entropy de-convolution (IMED) is proposed, which combines both the advantages of IMED in solving the influence of the long signal acquisition path and VME based on constructed reference in extracting the impulse and modulation characteristic of vibration signal. Firstly, IMED is used as signal preprocessing method to analyze the vibration signal of rotating machinery to eliminate the influence of long signal acquisition path and enhance the repetitive impulse characteristics. Then, reference signal is constructed according to the prior knowledge of the rotating machinery and input it with the output signal of IMED into the VME model together, and the output result of VME not only could further enhance the impulse characteristic of vibration signal, but also obtain the modulation characteristic simultaneously. Finally, envelope spectral or enhanced envelope spectral is performed on the output signal of VME and satisfactory fault features are extracted. In order to solve the shortcomings of traditional MED, an IMED based on D-norm is proposed which has higher computational efficiency and could extract multi-harmonic impulse features. In addition, VME based on constructed reference is proposed to improve the accuracy of VME in extracting the target signal. Feasibility and superiority of the proposed method are verified by one experimental case and one engineering case