Robotic Systems and Applications
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Vertical vibration modeling for 2:1-roping traction elevator system
Get PDFThis paper presents a vertical vibration model for 2:1-roping traction elevator system. In this model, masses of suspension ropes are considered and their kinetic energy is calculated by applying Rayleigh method. Equations of motion for free vibration are derived. To verify the improvement of the model, an output dependent only modal test scheme using eigenvalue realization algorithm is conducted to obtain natural frequencies from a real elevator installation. The comparison of experimental results and numerical results of proposed model and previous similar models is presented on calculation of natural frequencies. The results show that proposed model is able to reflect the 5th natural frequencies more exactly under 0 % and 100 % load conditions
Development and application of high-power advanced exploration drilling rig for coal mining TBM
Get PDFWith the continuous popularization and application of TBM equipment and technology in the field of coal mine, aiming at the problems of small torque and small propulsion of existing TBM advanced exploration drilling rigs for coal mine, which is difficult to drill long borehole, and lack of special high-power drilling equipment to match with it, a high-power drilling rig for coal mine TBM is developed. This paper introduces the structure of the drilling rig, analyzes the structure and principle of the luffing mechanism and the rotary table protection device, also the strength of the key parts. Through the application in Guineng Group Heilaga Juxin coal mine shows that this equipment has large torque and propulsion, the hydraulic system and operation mode meet the requirements of long-distance separate layout in TBM. The drilling rig has good stability and high efficiency, and can meet the various needs of long drilling for advanced exploration, which promotes the application of TBM equipment and technology in the field of coal mine
Study on magnetostriction characteristics under different measurement conditions under an externally compressive stress
Get PDFThe measurement of magnetostriction characteristics of grain-oriented electrical steel strip under an external compressive stress has always been a main focus in the process of magnetostriction measurement. There are difficulties in the measurement of magnetostriction, especially under compressive stress, mainly because the thickness of test specimen is small, and the test specimen is very easy to deform under the compressive stress. A weight should be placed on the test specimen to prevent a deformation of the test specimen when the measurement of magnetostriction characteristics under an externally compressive stress according to the IEC/TR 62581:2010. But how much weight and how to place aren’t concerned in IEC standard. In this paper, different weights were placed on the grain-oriented electrical steel test specimen under external compressive stress and zero stress. Through analyzed the measured magnetostriction data under different weights to determine the optimal measurement method of grain-oriented electrical steel strip under compressive stress and zero stress. The purpose of this paper is to find the most accurate and high reproducibility measurement method of magnetostriction, which can truly reflect the magnetostriction performance of grain-oriented electrical steel
Analysis of mechanical properties of steel-concrete joint of large-span hybrid beam bridge
Get PDFThe mechanical properties of the steel-concrete joint determine the mechanical properties of the whole bridge. The mechanical properties of the steel-concrete joint of Jianhua railway rigid-frame bridge are analyzed by using nonlinear finite element method. The results show that the overall stiffness transition of the joint is smooth, the maximum stress of concrete section and steel box girder section are lower than the design value of the strength, which indicates that the structural stiffness and strength of the steel-concrete joint section meets the requirements. The error range of the finite element analysis results and the measured data is within 6 %, which shows that the finite element method can simulate the actual stress state of the bridge and it could save a lot of time and energy compared to the actual test
Nonlinear dynamic analysis and defect detection of gears
Get PDFIn the current work, the nonlinear dynamic behavior of an eight degrees of freedom gear system is investigated. Tooth crack is introduced into the model. The main sources of excitation are the time varying mesh stiffness (TVMS), time varying mesh damping, backlash and friction inter teeth. By using the potential energy method applied into the cantilevered beam, the TVMS is calculated. The backlash is considered as a dead zone. The effect of backlash, friction and tooth crack on the vibration frequencies is highlighted. The crack detection is based on the time-frequency analysis
Experimental study on the effect of particle gradation on dewatering performance of geotubes
Get PDFTo clarify the effect of particle gradation of filling soil on the dewatering and consolidation performance of geotubes, the content of four-particle size classes (powder, fine, medium, and coarse) which are commonly used in engineering as the research object was taken. The dewatering rate, soil infiltration and solid-liquid mixing pressure in the bag with time when filling soil with different particles were studied, and the soil loss of the hanging bag was analyzed from the perspective of seepage soil gradation. The research results show that the dewatering process could be divided into the quick dewatering stage, silting stage, and stable stage according to the dewatering rate. According to the performance of soil conservation, it could be divided into the loss stage and reverse filtration stage. Further, based on the effects of powder content, non-uniformity coefficient, and curvature coefficient of soil on the dewatering rate of the hanging bag, a formula for calculating the dewatering rate of geotubes is summarized
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
Using vibration data to classify conditions in disk stack separators
Get PDFMounting sensors in disk stack separators is often a major challenge due to the operating conditions. However, a process cannot be optimally monitored without sensors. Virtual sensors can be a solution to calculate the sought parameters from measurable values. We measured the vibrations of disk stack separators and applied machine learning (ML) to detect whether the separator contains only water or whether particles are also present. We combined seven ML classification algorithms with three feature engineering strategies and evaluated our model successfully on vibration data of an experimental disk stack separator. Our experimental results demonstrate that random forest in combination with manual feature engineering using domain specific knowledge about suitable features outperforms all other models with an accuracy of 91.27 %
Genetic engineering – construction of a network of arbitrary dimension with periodic attractor
Get PDFIt is shown, how to construct a system of ordinary differential equations of arbitrary order, which has the periodic attractor and models some genetic network of arbitrary size. The construction is carried out by combining of multiple systems of lower dimensions with known periodic attractors. In our example the six-dimensional system is constructed, using two identical three-dimensional systems, which have stable periodic solutions
Structure and movement, let’s not kill Chronos
Get PDFThe myth of Chronos that devours his children is the allegorical expression of time that ends everything, but there is another reading: that time exists and allows us to understand the idea of a process, of evolution, both biologically and in any other aspect of life. The structure is the static, current, measurable morphological expression of everything that has a physical manifestation. Movement is the expression of life that is inexorably written on the structure and is responsible for its dynamism and change. We have developed the ability to analyse the structure in a systematic and detailed way, isolating it from time, and therefore depriving it of the movement that animates it, fixing the moment with static photographic images. With direct cephalometric techniques or on radiography we have defined points and reference systems, measured, compared, made proportions, and described the layout. Like the Art, the Morphological Sciences evolve from a two-dimensional vision to a three-dimensional one and we have given importance to empty spaces. But unlike art, we have difficulty internalizing and becoming aware of movement and the vital energy that animates it. Studying Movement means studying Form along Time. Structure and Function are two sides of the same coin, and our field is a clear example of this. We cannot work on occlusion without understanding the functions associated with the whole system: breathing, swallowing, chewing, are the main sources of stimuli responsible for the development of the Stomatognathic System, which has the movement as its main engine. In our clinical practice we are convinced that seeking an integration between Form and Function provides balance and health to the system and therefore delays the negative effects of Time, and coherently understanding the Form-Function-Time triad provides a broader understanding of development and balance of our system