Maintenance, Reliability and Condition Monitoring
Not a member yet
1200 research outputs found
Sort by
Corporeal-composition indicators, and physiological alterations in dental eruption
Get PDFWorldwide, obesity leads to major diseases in adults. Infants are affected as well, particularly because of growth and development issues. In this article we describe cases of early dental eruption in overweight and obese children, almost 1 year earlier than expected. The relations and mechanisms that cause these alterations remain to be determined
Experimental investigation of bi-modular material coating to enhance damping
Get PDFHard coatings can be used to increase damping when applied on the surface of the components of turbomachinery. This can be effective to reduce the resonant vibration level of components working in a high cycle fatigue environment due to the extremely high operational speed. This paper discusses the experimental investigation of a bi-modular material hard coating to enhance damping in structural steel elements. Firstly, a hard coating (Al2O3+MgO) is applied on AISI 304L stainless steel substrate by plasma spraying. After that, a layer of chrome is deposited by chrome plating. Dynamic responses of both coated and uncoated samples are measured. The damping ratio of the test specimen is extracted from the time response by the logarithmic decrement method. Improved damping capacity of the coated steel sample is observed and is mainly attributed to the thin coating of chrome on the steel structure. The natural frequency of coated specimen showed 8 to 10 % improvement, the forced response showed a 30 to 35 % decrement in displacement, the damping ratio showed a 200 % increment, and the time of decaying showed a 20 % decrement. The results of the present study provide new ideas for the development of high-damping structural elements
Höegh LNG and Altera Infrastructure is scaling up large scale CCS infrastructure
Get PDFIn a joint initiative, called “Stella Maris CCS” Altera Infrastructure and Höegh LNG are working together to provide cost efficient floating Carbon Capture and Storage infrastructure solutions for a global market, not limited to size or geographical location. Valuable infrastructure experience is brought together; with FPSO (Floating Production, Storage and Offloading) and Dynamically Positioned Shuttle Tankers from Altera and FSRU’s (Floating Storage Regasification Unit) from Höegh. We intend to continue to build on our heritage and experience, using our combined skills to contribute to carbon emission reduction around globe. With the “Stella Maris CCS” project, we will essentially be doing what we are doing today, only in reverse. Our solution, initiated in 2019 as the first of its kind, will offer a large-scale floating infrastructure for collection, transport, and injection of CO2 into subsea reservoirs/aquifers. Our infrastructure concept consists of 2-3 Carbon Collection Storage Units (CCSU) to aggregate volumes at different key locations, 3-4 CO2 Shuttle Carriers and one Floating Storage and Injection Unit, the total amount of CO2 injected with these assets can reach up to 10 million tons per year. In order to realize large scale CCS, the unit costs must come down, and the barriers for emitting industries to invest in capture plants must be lowered. With Stella Maris we are addressing these hurdles. The larger ship design enables carrying volumes of CO2 at low pressure and will allow for greater economies of scale in the absence of a pipeline which places less limitations on distance to reservoir and ultimate flow capacity. Having a centralized conditioning of CO2 in a CCSO hub allows more flexibility for on-site capture design from multiple onshore industrial emission sources with shared port access. To defray high logistics cost in e.g. the Baltic region, a hub and spoke transportation approach enables collection in smaller parcels, milk-run gathering and conditioning for large scale transfer for storage in an offshore subsea reservoir on the Norwegian Continental shelf
The importance of a realistic leakage evaluation to support public awareness and acceptance for carbon capture and storage
Get PDFCarbon Capture and Storage is not only highly recommended by the IPCC as a mechanism to significantly lower carbon emissions to the atmosphere, it is now also gaining traction in terms of large-scale implementation. Its importance is increasing in many parts of the world to directly decrease emissions from industrial sources, but also to lower the carbon footprint of blue hydrogen production. With most CCS projects being planned for offshore locations, public acceptance is less of a determining factor than it used to be 10-20 years ago, where discussions were rather for onshore locations. CO2 leakage has always been a risk highlighted in the public debate, while no or minimal leakage has been reported for current CCS projects worldwide. However, as scientific community, we need to realistically highlight the risk of leakage across sealing units for CO2 stored to inform various stakeholders like regulators, the public and of course also operating companies. Caprock leakage needs to be studied across various length and time scales, considering the undisturbed matrix as well as fracture networks and faults; we need to consider advective and diffusive flow and transport and incorporate mineral alterations, potentially leading to changes in hydraulic or mechanical properties. This talk will highlight the current state of research, advancements and future research required for a realistic evaluation of caprock leakage. It will be based on past research related to matrix transport as well as current research focusing on single and multiphase flow along faults and fractures
Greensand project – transport and offshore storage of CO2 in Denmark – status, outlook and challenges
Get PDFThe Greensand project includes, beside from safe and efficient geological offshore CO2 storage, offshore transport by ship and/or pipeline of CO2 from key side onshore facilities established to capture, liquefy, onshore transport and temporarily store the CO2 before offloading to storage site. The Greensand project builds on the usage of the offshore Siri complex sandstone reservoirs no longer in use for oil and gas production. The storage sites, offloading and injection systems and transportation means are currently being technically matured. The target is to be able to offer customers safe and reliable transport and storage services from the start of 2026. Currently meanwhile maturing a technical concept, commercial and regulatory activities are ongoing in parallel. The Greensand partners INEOS Energy and Wintershall Dea have also decided to perform an offshore pilot test of injecting liquified CO2 into a particular reservoir serving as candidate for future long terms storage of CO2. Along the pilot testing offshore project, material testing and deployment of monitoring techniques are being matured. The Pilot testing offshore planned to take place late 2022 with a 3-months duration
The interface between dental topography and functional appliances accessories
Get PDFDental topography can be defined as the division of receptive fields that we have in the crown of the tooth. It is necessary that we understand this concept very well because it makes all the difference in clinical practice. We need to understand the receptive fields of the tooth, and we must use this knowledge when prescribing accessories for a functional appliance, understanding its function and where these accessories should touch to generate the expected effect. In this paper we will discuss the fundamentals of dental topography and show some accessories used on the therapeutic arsenal of Jaw Functional Orthopedics
Clinical application of digitalization of occlusal contacts with dental scanner
Get PDFThis study aimed to evaluate the number, intensity and position of occlusal contact points in a case of mesiocclusion, hyperdivergence, with open bite. An occlusal record was taken from a patient with anterior and lateral open bite mesiocclusion, using the Planmeca Esmerald S intraoral scanner in maximum intercuspation. The intensity of the occlusal contact was analyzed with the software 3shape Ortho Analyzer Orthodontics, using the Occlusion Map module, through the 3D Color Map tool, with a 0.5 mm virtual articular paper. These results were compared to the occlusal support points defined by Planas [10]. The interpretation of the data obtained was made by assessing the interocclusal intensity of the contact points, number of contacts and position during three different moments (1S, 2S, 3S) in the record taking process. The chromatic scale of the Color Map is: red, orange, yellow, green and blue. To identify the occlusal contact points in digital, they are shown in red points when full contact occurs, while minimum contact is shown in blue. We evaluated the number of teeth with interocclusal contacts. It was determined that having the appropriate number of contacts does not imply that they are in the correct position. In addition, the method suggests reliability in the filing and record keeping of occlusal contacts. By identifying intensity, number and position of the occlusal support point we can objectively record interocclusal alterations
Three-dimensional numerical simulation of multi-physical coupled environment during electromagnetic propulsion
Get PDFElectromagnetic propulsion technology is a new propulsion technology which uses electromagnetic force to push objects into high or ultra-high speed. However, during propulsion, the armature and launch load are affected by harsh multi-physics environment. The coupled effect was often ignored or over idealized in previous numerical simulations, which leads to large errors between simulation and experiment. In this paper, a three-dimensional multi-physics coupling environment simulation model is established. The distribution of electromagnetic field, structure field and temperature field in armature from static to high speed are effectively calculated. Moreover, the coupled effect between physical fields and the influence of key parameters on the simulation results are revealed. In conclusion, this model can reproduce the physical field distribution of armature and rail during electromagnetic propulsion. The time-varying resistance and inductance and the velocity skin effect (VSE) are the key parameters affecting armature movement. This method reveals a feasible path for the simplification of multi-physical model and the mitigation of extreme environment
Simulation and experimental analysis of tip response of tapping mode atomic force microscope
Get PDFIn this study, the vertical deflection responses of tapping mode atomic force microscope (TM-AFM) micro-cantilever tip are obtained by simulation and experiment. The results show that, under the blocking of the sample on one side, the steady-state response of the tip is still a sinusoidal form almost symmetrical about the equilibrium position. Furthermore, from the perspective of energy dissipation of the micro-cantilever system, the phases of two surfaces with different properties are simulated under different background dissipation. The result shows that eliminating partial background dissipation can increase the phase contrast between the two surfaces. These results are of significance for understanding the tip response and phase optimization in TM-AFM
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