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Artigos de revistas sobre o assunto "Modèle dit location-scale"
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Chen, Faquan, Miaolei Deng, Hui Gao, Xiaoya Yang e Dexian Zhang. "ACA-Net: An Adaptive Convolution and Anchor Network for Metallic Surface Defect Detection". Applied Sciences 12, n.º 16 (12 de agosto de 2022): 8070. http://dx.doi.org/10.3390/app12168070.
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Metallic surface defect detection is critical to ensure the quality of industrial products. Recently, human-advanced surface defect detection algorithms have been proposed. Most of these algorithms rely on convolutional neural networks (CNN) and an anchoring scheme. However, a convolution unit only samples the input feature maps at fixed shapes and locations. Similarly, a set of anchors are uniformly predefined with fixed scales and shapes, which increases the difficulties of bounding box regression. Therefore, we propose an adaptive convolution and anchor network for metallic surface defect detection, named ACA-Net. Specifically, an adaptive convolution and anchor (ACA) module is proposed, which mainly consists of adaptive convolution and an adaptive anchor. Firstly, an adaptive convolution module (ACM) is designed, which adaptively determines the location and shape of each convolution unit. In addition, a multi-scale feature adaptive fusion (MFAF) is proposed, which is used in ACM to extract and integrate multi-scale features. Then, an adaptive anchor module (AAM) is proposed to yield more suitable anchor boxes by adaptively adjusting shapes. Extensive experiments on NEU-DET dataset and GC10 dataset validate the performance of the proposed approach. ACA-Net achieves 1.8% on NEU-DET dataset higher Average Precision (AP) than GA-RetinaNet. Furthermore, the proposed ACA module is also adopted in GA-Faster R-CNN, improving the AP by 1.2% on NEU-DET dataset.
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Wang, ChaoFeng, Congyue Wang, Lele Wang, Yuanhong Li e Yubin Lan. "Real-Time Tracking Based on Improved YOLOv5 Detection in Orchard Environment for Dragon Fruit". Journal of the ASABE 66, n.º 5 (2023): 1109–24. http://dx.doi.org/10.13031/ja.15643.
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Highlights This method has achieved faster detection speed while maintaining accuracy. It is a real-time tracking method that can track dragon fruits in orchard environments in real-time. The introduction of an attention mechanism in the network provides good robustness to changes in lighting and target scale. Abstract. This article addresses the issue of dragon fruit real-time detection in orchard environments and proposes a real-time detection and tracking model for dragon fruit using an improved YOLOv5 object detection algorithm and Deep-sort object tracking algorithm. By applying real-time tracking to dragon fruit harvesting, the tracking algorithm provides timely feedback on the fruit's location, allowing for prompt correction of environmental issues that may affect the accuracy of the harvesting process. This approach enhances the robustness of the target positioning algorithm. First,based on the YOLOv5 object detection algorithm, the Convolutional Block Attention Module and Transformer self-attention mechanism are introduced to construct a YOLOv5s-DFT object detection model that is more suitable for dragon fruit detection. Next, Combining the Deep-sort multi-object tracking algorithm, this article proposes a real-time detection and tracking method for dragon fruit in the orchard environment. The YOLOv5s-DFT model was trained and experimented with using a self-built dataset. The trained model weight is only 19.26% of YOLOv7. The experimental result shows that, while ensuring detection accuracy, YOLOv5s-DFT has a faster detection speed in dragon fruit detection, with an average frame time of 0.01673 s, which is 0.00422 s faster than the original YOLOv5s. When tracking dragon fruit using the Deep-sort tracking algorithm, it can track dragon fruit at a speed of 47.08 frames per second. When utilizing the Deep-sort tracking algorithm to track dragon fruit, it achieves a tracking speed of 47.08 frames per second, enabling real-time acquisition of the fruit's position information. This technology provides technical assistance for the intelligent harvesting of dragon fruit and the intelligent management of dragon fruit orchards. Keywords: Dragon fruit, Improved YOLOv5, Orchard environment, Real-time tracking.
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ZHU, Xiaoyan, Xin WAN e Mingyu ZHANG. "EMC-YOLO: A feature enhancement and fusion based surface defect detection for hot rolled strip steel". Engineering Research Express, 8 de janeiro de 2025. https://doi.org/10.1088/2631-8695/ada7c4.
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Abstract Steel is one of the most common and widely used materials in modern industrial production, and has been widely and deeply used in the field of engineering construction. However, the manufacturing process and external factors can lead to defect problems that seriously affect the quality and appearance of the steel. Defects have the characteristics of multi-scale, weak texture, many dense and small defects, and interference in the processing environment, which are challenging for the actual location and classification of defects. The detection of these surface defects is challenging due to their multi-scale nature, weak textures, numerous small defects, and complex background interference. To address these challenges, an EMC-YOLO algorithm is proposed to detect defects accurately. First, an Enhanced Fast Feature Extraction (EFFE) module is constructed. It integrates local saliency information with global saliency information and achieves multi-depth feature fusion. The EFFE replaces the bottleneck structure of C2F, enhancing feature extraction capabilities.Secondly, in order to optimize multi-scale defect feature detection and background interference of long defects, a multi-scale receptive field space pool Fast pyramid (MRF-SPPF) module is proposed. Finally, Cross-Reinforced Connections Across Spatial Features (CCASF) is combined with small target detection layer to give full play to the feature representation extracted after backbone enhancement, and it is deeply integrated with neck features.This closely links the enhanced backbone features with the enriched neck features. On the NEU-DET dataset, the mAP value of the proposed model is improved by 3.5%, and the accuracy of the model finally reaches 80.7%. At the same time, in another GC10-DET dataset, our model also achieved 73.5% mAP value. It achieves good accuracy while satisfying real-time performance. It has a good application prospect in the actual strip processing.
Teses / dissertações sobre o assunto "Modèle dit location-scale"
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Flament, Guillaume. "Modélisation statistique de l'impact du risque climatique sur la solvabilité des banques". Electronic Thesis or Diss., Rennes, École Nationale de la Statistique et de l'Analyse de l'Information, 2024. http://www.theses.fr/2024NSAIM002.
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Cette thèse propose une adaptation du modèle de Merton-Vasicek. Ce modèle à facteur commun permet de calculer les pertes extrêmes liées à un portefeuille de crédits. Usuellement, ce facteur est considéré comme étant Gaussien et le modèle ne permet pas l’intégration de variables macroéconomiques. Dans ce manuscrit nous proposons de définir les pertes extrêmes à partir des quanti les du facteur commun conditionnels à des variables macroéconomiques. Nous proposons deux types de modèles semi-paramétriques pour es timer ces quantités. Nous montrons leur perti nence aussi bien sur des exercices numériques que sur des données réelles.Cependant, intégrer le risque climatique dans le calcul de pertes extrêmes nécessite l’introduction de scénarios macroéconomiques qui serviront ensuite de variables explicatives dans ce modèle de Merton-Vasicek. Nous pro posons donc d’intégrer des contraintes environ nementales dans un IAM, le modèle DICE. En particulier, nous proposons d’intégrer Vexergy dans la modélisation de la productivité totale des facteurs avant d’intégrer cette modélisation pour générer des trajectoires de (dé-)croissance économique, qui pourrait ensuite être inté grée comme variable explicative aux modèles précédemment présentésTins manuscript proposes an adap tation of the Merton-Vasicek model. This single-factor model allows for the calculation of financial losses related to crédit. Typically, this factor is considered Gaussian, and the model do es not allow for the intégration of macroeconomic variables. In this manuscript, we propose to compote this loss based on the quantile of the common factor conditional on macroeconomic variables. We propose two semiparametric types of models to estimate these quantifies. We demonstrate their rele- vance through bot h numerical exercises and real data.However, integrating climate risk into the cal culation of extreme losses requires the intro duction of macroeconomic scénarios that will then serve as explanatory variables in this Merton-Vasicek model. We hâve therefore pro- posed to integrate environmental constraints into an IAM, the DICE model. Specifically, we propose to integrate exergy into the model ing of the Total Factor Productivity (TEP). Next, it is possible to incorporate the pré dictions of the TFP to generate trajectories of (de-)growth that could eventually be inte- grated as explanatory variables into the condi tional quantile models
Capítulos de livros sobre o assunto "Modèle dit location-scale"
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Rodríguez-Pose, Andrés. "Social Conditions and Regional Growth in Western Europe". In The Dynamics of Regional Growth in Europe, 97–135. Oxford University PressOxford, 1998. http://dx.doi.org/10.1093/oso/9780198233831.003.0005.
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Abstract In the Introduction it was argued that social and political conditions today play a greater—or, at least, more visible—role in the determination of the growth potential of an area than they did at the high point of the model of mass production. The flexibilization of the productive system seems to have shaken the traditional bases of locational analysis, allowing a greater decentralization of the centres of production and a reduction of the initial costs of setting up industries. In this context, technological advances have rendered physical distances and the dependency levels on raw materials and labour less important. In addition, the organizational systems of most firms have been substantially transformed. A vertical organization is no longer an essential element in order to maximize benefits, neither are economies of scale, scope, or the existence of externalities absolutely necessary. Instead, the creation of both production and informational networks is sought after, as is a way in which different productive entities can be integrated with them. As a result, one can say that the spatial spectrum of the location of firms has expanded enormously, owing to the fact that the basic factors which determine the placement of production plants-capital, raw materials, and labour—now possess greater mobility than ever before.
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Ganteaume, Anne, Bruno Guillaume e Bertrand Girardin. "Impact of the WUI vegetation management on damage to building: comparing post-fire damage assessment and CFD modelling results." In Advances in Forest Fire Research 2022, 626–37. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_95.
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In most Wildland-Urban Interface (WUI) fires, damage to building can result from poor vegetation management, comprising a lack of mandatory brush-clearing around building or an unwise location of trees (e.g. too close to building or overhanging the roof). It was interesting to check if post fire damage can be predicted by CFD fire modelling in different scenarios of vegetation management (treated vs untreated) according to different past-fire events. Ultimately, this work will help to assess if the fuel treatment regulation in the framework of fire prevention is efficient and to pinpoint possible limitations. Different scenarios of vegetation treatments were tested on four study cases of dwellings surrounded by gardens juxtaposed to wildland vegetation (therefore submitted to the regulation on fuel management in WUI) that were affected by the Vidauban fire in 2003 or the Rognac fire in 2016 (SE France). In each case, comparisons of modeled and observed fire behaviour and impacts on buildings were performed using the Fire Dynamic Simulator model (FDS) and very accurate georeferenced ornamental vegetation mapping, especially around buildings. Despite problems to adapt FDS modelling to the high fuel moisture content (FMC) of some species, results showed that overall brush-clearing mitigated fire intensity and propagation and therefore damage to building and ornamental vegetation, sometimes highlighting that this fuel management measure could be softened (decreasing the radius treated) or, on the contrary, strengthened according to the topography and wind. The fuel biomass treatment involving vegetation residues left on site was also found as deleterious as the lack of treatment. Overall, the modelling using FDS, at the WUI scale and taking into account a very refined vegetation distribution, was mostly successfully validated by post-fire damage recorded during the past-fire events, which was rarely attempted in the complex environment of forest fires in the French Mediterranean area. The current scientific limitations of the model did not allowed obtaining realistic results in terms of heat flux received by the building, even if they were coherent in global intensity comparing treated and untreated vegetation, and have to be addressed in future improvements of the model.
Trabalhos de conferências sobre o assunto "Modèle dit location-scale"
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Sander, Edward A., Kyle P. Quinn, Beth A. Winkelstein e Victor H. Barocas. "Localizing Damage in the Cervical Facet Capsular Ligament With Image-Based Multiscale Models". In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19271.
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Excessive soft tissue loading can produce pathophysiological changes in the absence of tissue failure or visible injury [1]. In these cases, strain has often been used as a metric to infer the location of damage and define tissue tolerances due to a lack of any other means to detect injury. A recent study of the human facet capsular ligament identified localized anomalous collagen fiber realignment prior to gross failure by correlating fiber alignment vectors derived from quantitative polarized light imaging [1]. The onset of anomalous fiber realignment was strongly associated with a decrease in tissue stiffness in that study, suggesting the occurrence of damage, but the location of this putative damage did not correspond to the location of maximum principal strain. The disconnect between maximum strain and the location of damage may be explained by the heterogeneous structural organization of the facet capsular ligament. By employing image-based multiscale computational models, which account for the local fiber alignment of the tissue, we hypothesized that estimates of the tissue stress field may predict the development of microstructural damage that occurs outside of the location of maximum strain. In this study, multi-scale fiber network models were compared to the experimentally-derived strain fields during facet capsular ligament loading up to the detection of anomalous fiber realignment to begin to understand the relationships between macroscopic tissue loading, collagen fiber reorganization, and the development of initial localized microstructural damage.
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Gioioso, Paul M., e Jorge Rodriguez. "A Numerical Study of Non Uniform Multiple Site Cracks Emanating From a Two Dimensional Rivet Hole Array". In ASME 1993 International Computers in Engineering Conference and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/cie1993-0042.
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Abstract A study was performed to assess the effect of multiple site damage (MSD), which has been observed in a number of aging aircraft, on the fatigue life of lap splice joints in fuselage structures. Numerical modeling was used to simulate various MSD occurrences in models similar to riveted aircraft structures (e.g. rows of 5/32″ diameter holes separated by a finite distance, for a T2024-T3 aluminum material) under simulated fatigue loading. Several geometric factors were examined, and their effect on MSD propagation investigated. Nonuniform MSD was also modeled, and all effects were compared on a global scale. Results indicate that a tighter array configuration allowed for a shorter fatigue life, as did the introduction of the nonuniform crack. However, the effect of the staggered offset was negligible in comparison to the effect of the rivet spacing and the location of the nonuniform crack. The size and initial location of the nonuniform crack had the greatest influence on the stress distribution and the fatigue life.
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Lyu, Yelin, Ning Wang e Hangqi Tian. "Coordinated Charging and Dispatching for Large-Scale Electric Taxi Fleets Based on Bi-Level Spatiotemporal Optimization". In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-01-2880.
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<div class="section abstract"><div class="htmlview paragraph">The operation management of electric Taxi fleets requires cooperative optimization of Charging and Dispatching. The challenge is to make real-time decisions about which is the optimal charging station or passenger for each vehicle in the fleet. With the rapid advancement of Vehicle Internet of Things (VIOT) technologies, the aforementioned challenge can be readily addressed by leveraging big data analytics and machine learning algorithms, thereby contributing to smarter transportation systems. This study focuses on optimizing real-time decision-making for charging and dispatching in large-scale electric taxi fleets to improve their long-term benefits. To achieve this goal, a spatiotemporal decision framework using Bi-level optimization is proposed. Initially, a deep reinforcement learning-based model is built to estimate the value of charging and order dispatching under uncertainty. The model considers the long-term costs and benefits of different tasks and guides whether electric taxis should prioritize charging or order dispatching for the fleet's long-term benefits. Subsequently, a combinatorial optimization approach is employed to determine the specific targets for charging or order dispatching. Case studies are conducted within real-world operation data from electric taxis in Hangzhou City, China. The results validate the efficacy of the proposed method, as compared to a baseline approach. Across various fleet sizes and charging power conditions, the method significantly reduces non-service time during the charging process by optimizing charging time and location. The proposed method is found to be suitable for large-scale fleets and high-charging power scenarios.</div></div>
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LaVoy, Rosanne M., Fred Babian, Matthew Mulholland e Scott Silverman. "The Changing Role of Advanced Sample Preparation in X-Ray Inspection Supporting 2.5D and 3D Sample Failure Analysis". In ISTFA 2015. ASM International, 2015. http://dx.doi.org/10.31399/asm.cp.istfa2015p0466.
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Abstract The X-ray inspection of fully assembled samples is becoming ever more important as the benefits of using area array packages/chip scale packages/flip chips are applied to more and more products. Sample preparation has traditionally been used to improve access to geometry or a specific location with a known defect that requires verification. The novel paradigm is an integrated approach to sample preparation and X-ray inspection to optimize resolution and throughput time performance with minimally deprocessed sample. This paper, covering the limitations of X-Ray imaging and 3D tomographic reconstruction, discusses the development of models for throughput time and resolution by failure analysis labs. It also discusses the processes involved in advanced sample preparation techniques and global BGA removal to obtain improved resolution at die level.
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Bhatt, Mrugank P., Pengze Yang e Chaouki Habchi. "Numerical Modeling of Liquid Film Boiling, Urea Deposition and Solidification in SCR Applications". In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-01-2626.
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<div class="section abstract"><div class="htmlview paragraph">The proposed Euro 7 regulation aims to substantially reduce the <i>NO<sub>x</sub></i> emissions to 0.03 g/km, a trend also seen in upcoming China 6b and US EPA regulations. Meeting these stringent requirements necessitates advancements in Urea/Selective Catalytic Reduction (SCR) aftertreatment systems, with the urea deposit formation being a key challenge to its design. It’s proven that Computational Fluid Dynamics (CFD) can be an effective tool to predict Urea deposits. Transient wall temperature prediction is crucial in Urea deposit modeling. Additionally, fully understanding the kinetics of urea decomposition and by-products solidification are also critical in predicting the deposit amount and its location. In this study, we introduce (i) a novel film boiling model (IFPEN-BRT model) and (ii) a new urea by-product solidification model in the CONVERGE CFD commercial solver, and validate the results against the recent experiments. The IFPEN-BRT model handles the spray-wall heat transfer in various boiling regimes, and the urea by-product solidification model separates solid deposits from liquid film parcels and renders them inert on the walls. We couple the by-product solidification model with the detailed decomposition model for urea. We use surface morphing feature developed in CONVERGE to enable realistic representation of solid surface topology once the solid deposits are formed on the testing plate. Multiple acceleration schemes have been employed to achieve a faster turnaround time while maintaining high fidelity. Additionally, the fixed flow approach has been used to accelerate the simulation and reach the time scale required for appreciable deposit formation. The simulations, incorporating both the IFPEN-BRT model and the urea by-product solidification model, matches the experiments very well on several fronts: the wall temperature contours, the temporal evolution of wall temperature profiles, and film/deposit patterns. The simulations also correctly predict cyanuric acid (CYA) as the primary solid deposit, aligning with experimental findings after 20 minutes real time simulation.</div></div>
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Woodard, Brian, Michael Bragg e Timothy G. Smith. "The Effect of Large Droplet and Spanwise Ridge Ice Accretion on the Aerodynamic Performance of Swept Wings". In International Conference on Icing of Aircraft, Engines, and Structures. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-1385.
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<div class="section abstract"><div class="htmlview paragraph">Wind tunnel tests were performed on an 8.9-percent scale semispan wing in the Wichita State University 7x10-foot wind tunnel with simulated ice accretion shapes. Simulated ice shapes from large-droplet clouds, simple-geometry ice horn shapes, and simple-geometry spanwise ridge shapes typical of runback icing were tested. Three Reynolds number and Mach number combinations were tested over a range of angles of attack. Aerodynamic forces and moments were acquired from the tunnel balance and surface pressures and oil flow visualizations were acquired. This research supplements the Swept Wing Icing Program recently concluded by NASA, FAA, ONERA, and their partners by testing new ice shapes on the same wind tunnel model. Additional surface roughness was added to simulate large-droplet ice accretion aft of the highly three-dimensional primary ice shape, and it had little effect on the wing aerodynamic performance. Spanwise ridge simulations produced large increases in drag and small increases in maximum lift in most cases. Ridge size and location had significant effects on the performance and the lower-surface ridge was important contributing to the drag at low angle of attack and lift at high angle of attack due to the movement of the attachment line around the leading edge. Oil flow visualization and surface pressures help explain the spanwise effects on the flowfield and the resulting changes in lift and moment produced by the various ice shape simulations. Studies of a partial-span ridge simulating a residual icing case and additional simple horn cases to supplement SWIP data are also presented. The aerodynamic performance results from the simple horn ice cases are consistent with the previously identified trends in earlier studies with a more limited range of horn angles.</div></div>
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Papageorge, Michael, e Jeff Colwell. "Evaluating Fire Propagation into the Passenger Compartment via Full-Scale Burn Testing". In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-01-2502.
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<div class="section abstract"><div class="htmlview paragraph">Two full-scale burn tests were conducted to evaluate the propagation of an engine compartment fire into the passenger compartment of consumer vehicles. In particular, the effect of penetrations in the bulkhead separating the engine compartment from the passenger compartment was examined. The first burn test involved two vehicles of the same year, make, and model. One of the vehicles was left in the original equipment manufacturer (OEM) configuration. The other vehicle was modified by welding steel plates over the pass-through locations in the bulkhead between the engine and passenger compartments. After the fire was initiated in the engine compartment and had reached the onset of flashover, the heat and flames from this fire began to effect the passenger compartment. At about this same time, flames extending from the engine compartment around the hood began impinging directly on the outer face of the windshield. The passenger compartment temperature first increased on both vehicles at an under-dash location near the bulkhead. Once the windshields failed the temperature of the airspace in occupant compartment that the driver or passengers would occupy and the headrest heat flux rapidly increased. A second burn demonstration involved a single mini-van with a windshield that had been fractured in a way similar to what would be expected during a front-end collision. As the fire that was initiated in the engine compartment interacted with the windshield, it failed in locations where there was existing mechanical damage to the windshield. The fire propagated into the vehicle via the broken windshield when the engine compartment fire was visually smaller than in testing in which the windshield was undamaged before the fire.</div></div>
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Bartkus, Tadas, Sam Lee e Eric Stewart. "Icing Physics Studies Using the 3D SIDRM Test Article: Aerodynamic and Supercooled Liquid Icing Analysis". In International Conference on Icing of Aircraft, Engines, and Structures. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-1399.
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<div class="section abstract"><div class="htmlview paragraph">In-flight icing is an important safety issue and is a factor that affects aircraft design and performance. Newer regulations are driving a need for improvements in airframe and engine icing simulation capability. Experimental data is required for development of icing physics models and simulation validation. To that end, this paper presents the analysis of the supercooled liquid icing data subset from tests conducted in 2022 at the NASA Icing Research Tunnel that studied both supercooled water and ice-crystal icing. The test article that was utilized replicated 3D geometrical features of an inter-compressor duct and strut region of a turbofan engine. The surfaces of the Simulated Inter-compressor Duct Research Model (SIDRM) can be heated to simulate the warm surfaces of the turbofan inter-compressor duct. The test article is instrumented with pressure taps, heaters, heat flux gauges, and thermocouples, while a 3D laser scanner, cameras, and a scale to measure ice mass were utilized to characterize the icing behavior. The aim of these tests was to generate ice accretions on the SIDRM test article under well-characterized supercooled liquid icing and ice crystal icing conditions. This paper discusses measurements related to aerodynamic testing and supercooled liquid icing tests that were conducted. Aerodynamic measurements were analyzed and compared to computational simulations and were found to be in good agreement for the range of airspeeds (50 to 230 knots) and angles of attack (0 to 4°) tested. Various parametric sweeps were conducted during the supercooled liquid icing portion of the test entry (cloud median volumetric diameter ranged from 15 to 90 μm, total air temperature from -3 to -17 °C, angle of attack from 0 to 4°, and accretion time from 5 to 20 min). These sweeps were performed to measure that parameter’s impact on ice accretion size, location (icing extent), characteristics (such as glaze/rime ice and shedding behavior), and test article surface temperature. Analysis of the test data showed that clouds composed of larger drops, colder air temperatures, smaller angles of attack, and longer spray times were the primary parameters that resulted in accretions with greater ice mass. Test article angle of attack and cloud droplet size influenced the location of ice accretion as these two parameters directly impact collection efficiency. With respect to icing characteristics, total air temperature dictated icing type, and smaller cloud drop size along with warmer air temperatures resulted in greater amounts of ice shedding. Surface temperature increased during ice accretion from the release of latent (fusion) heat, where total air temperature and cloud drop size impacted the amount of surface temperature change. The icing measurements collected during the SIDRM tests will be used to develop and validate 3D computational engine icing tools, such as GlennICE, that predictively assesses the onset and growth of ice. One of the goals of the sponsoring NASA project is to develop simulation models and tools that can assist in the design and certification of engines for flight in icing conditions in a cost-effective way.</div></div>
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Chatterjee, A., A. Younessi Sinaki e A. Ghosh. "Principles for Best Practice Geomechanics for CO2 Sequestration in Depleted Reservoirs". In SPE/IADC Asia Pacific Drilling Technology Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/219641-ms.
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Abstract As the world is facing challenging climate targets, one of the initiatives is to reduce carbon dioxide (CO2) emission through carbon capture and storage (CCS). However, to understand the viability of CCS study, field scale geomechanical risk assessment is key to determine short- and long-term injection and storage capacity. A comprehensive study was carried out to investigate the geomechanical risks associated with injection in the depleted reservoirs. This was done by preparing well-centric (1D) geomechanical models using inputs from petrophysical, drilling and production data of historical wells. This was then extended to a 3D geomechanical model for the entire area of interest in the field. The model was then used to investigate the caprock integrity (threshold of maximum injection pressure), reactivation of the existing faults (caprock & reservoir) and thermal stress effect on caprock & reservoir, A caprock integrity analysis was carried out for all the storage layers, and it was found that the storage layer pressures (reservoir pressure increase during injection) did not exceed the fracture pressure values of the caprock that will cause tensile failure. A fault stability analysis was carried out for the modelled faults and the Tau ratio for the maximum reservoir pressure (close or greater than initial reservoir pressure) was calculated. Results shows that there is no risk of fault stability using the current injection design (injection pressures close to the initial reservoir pressure). The stress changes induced by the thermal expansion/contraction of the rocks are calculated from the thermoelastic equations for the start of injection stage for both the reservoir and caprock. The caprock fracture pressure incorporating the thermal stress effect at the well location reduced significantly for the shallowest storage layer. With the focus of managing carbon emissions, this is one of the best principal practices and fit for purpose methodology which can be adopted for field scale geomechanical risk assessment to evaluate the short- and long-term CO2 injection risk and storage capacity in any field of interest.
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Iino, A. "CCS Development Optimisation via a Cost-Effective Reservoir Simulation Technology: Full-Field Simulation of CO2 Sequestration with Conductive Faults by Embedded Discrete Fracture Model". In APOGCE 2024. SPE, 2024. http://dx.doi.org/10.2118/221260-ms.
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Abstract For the robust planning and implementation of Carbon Dioxide Capture and Storage (CCS) projects, capacity and injectivity of target reservoirs and containment capability of cap rock formation need to be evaluated thoroughly through high-fidelity flow simulations with various hypothetical subsurface scenarios. Impact of conductive faults, which may act as high permeability conduits for the injected CO2, should be carefully assessed as the fault conductivity is typically highly uncertain. However, it is challenging to incorporate numerous faults with high conductivity and complex multi-phase displacement process in a practical framework of flow simulations. In this study, we present an efficient workflow using an Embedded Discrete Fracture Model (EDFM) to simulate CO2 flow via conductive faults and its application to the full-field scale assessment. The EDFM approach has been proposed to efficiently incorporate discrete fractures in flow simulations. Based on the pre-defined permeability, geometry and location of discrete fractures, transmissibility is computed (1) between each fracture and reservoir matrix and (2) at intersections of two fractures. In our application, conductive faults were assumed as discrete fractures. Extra grid blocks are added to the original reservoir grid system to represent discrete fractures by assigning the computed transmissibility via non-neighbor connections (NNCs). This approach involves no upscaling, no unstructured gridding and no local grid refinement and can be coupled with any commercial reservoir simulators. Multi-phase displacement process through individual faults can also be modeled. We demonstrate the efficiency and robustness of our proposed approach for synthetic and field scale examples. We first validated the CCS simulation with the EDFM approach for a producing gas reservoir using an illustrative 3-D example. Next, we present the application to a full-field simulation model where more than one hundred faults were interpreted based on the seismic data, to evaluate the CO2 breakthrough risk to up-dip gas producers. The simulation results show that the injected CO2 preferably migrates along conductive faults. leading to the earlier breakthrough as compared to the case without conductive faults. However, it was also confirmed that the CO2 production rate was not significantly increased even after the breakthrough. This study showed the effectiveness of the EDFM approach to simulate CO2 flow via numerous conductive faults in both edge aquifer and gas zones. This approach is also simple and easy to implement, which allows efficient application to full-field simulation models.