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Articles 1 - 30 of 83
Full-Text Articles in Engineering
Hierarchical Carbon Structures With Vertically- Aligned Nanotube Carpets For Oil-Water Separation Under Different Conditions, Kimia Kiaei
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The primary purpose of this study is to investigate the role of surface nano-structuring in fluid separation. It is hypothesized that hierarchical carbon structures consisting of aligned carbon nanotube arrays strongly adhered to the surface of porous carbon solids such as fabric and foam, can be used for separation of polar and non-polar fluids by selective wettability of one fluid and rejection of another. The vertically-aligned carbon nanotube arrays, as synthesized, possess super hydrophobicity demonstrated by high water contact angle on their surfaces. On the other hand, they are incredibly oleophilic, showing a high affinity to adsorb oil. These properties …
Preparation And Characterization Of Porous Pdms For Printed Electronics, Eyad Khalid M. Balbaid
Preparation And Characterization Of Porous Pdms For Printed Electronics, Eyad Khalid M. Balbaid
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Fabricating an elastomeric substrate with internal features could provide a novel structure with distinctive mechanical properties that allow them to stretch, bend and absorb the impact force. To date, polydimethylsiloxane (PDMS) is a great candidate as a substrate for flexible electronic applications, due to easy fabrication, high stability and low cost. In the current thesis, porous PDMS samples are fabricated and characterized based on the particle size and the fusion of salt and sugar treated micro-regions. The liquid PDMS is prepared by mixing the silicon elastomer base (Sylgard 184) and elastomer curing agent using volume ration 10:1. The salt and …
Tapped-Inductor Buck Dc-Dc Converter, Ankit Chadha
Tapped-Inductor Buck Dc-Dc Converter, Ankit Chadha
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There is a high demand for low step-down dc voltage conversions. Many conventional power converters that are currently being used have a moderate conversion ratio and this may not be sufficient to meet the demand. This can be achieved by either cascading power converters or using converters with a low step-down conversion ratio. Cascading the converters increases the power conversion stage complexity and increase the order of the system, while also affecting the stability. Using converters with a high conversion ratio seems to be a more intelligent option to root. This dissertation tackles to analyze one such converter, called tapped-inductor …
Chondroitin Sulfate Hydrogels For Total Wound Care Devices, Tushar Goswami
Chondroitin Sulfate Hydrogels For Total Wound Care Devices, Tushar Goswami
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Chondroitin sulfate (CS) is a naturally occurring bio-polymer found in areas of high cartilage in mammals. In directed applications, such as hydrogels, CS can be used to impact keratinocyte growth cycles. In this work, CS based hydrogels were utilized to accelerate wound healing and, in conjunction with a graphene sensor, monitor wound fluid pH. The hydrogels were cast onto a graphene field effect transistor (GFET) to obtain the benefits of the hydrogel wound healing capabilities, while also utilizing the pH sensitivity of the graphene. Results showed that the hydrogel caused a fivefold increase in cell size over the course of …
Analyzing Public View Towards Vaccination Using Twitter, Mahajan Rutuja
Analyzing Public View Towards Vaccination Using Twitter, Mahajan Rutuja
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Educating people about vaccination tends to target vaccine acceptance and reduction of hesitancy. Social media provides a promising platform for studying public perception regarding vaccination. In this study, we harvested tweets over a year related to vaccines from February 2018 to January 2019. We present a two-stage classifier to: (1) classify the tweets as relevant or non-relevant and (2) categorize them in terms of pro-vaccination, anti-vaccination, or neutral outlook. We found that the classifier was able to distinguish clearly between anti-vaccination and pro-vaccination tweets, but also misclassified many of these as neutral. Using Latent Dirichlet Allocation, we found that two …
Use Of Virtual Reality Technology In Medical Training And Patient Rehabilitation, Sankalp Mishra
Use Of Virtual Reality Technology In Medical Training And Patient Rehabilitation, Sankalp Mishra
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Coaching patients to follow the rehabilitation routines correctly and timely after surgery is often a challenge due to the limited medical knowledge of patients and limited availability of clinicians. Similarly, it is also a challenge to train medical professionals with both the technical and communication skills required in their practices. The recent emergence of VR technologies shines the light on improving the current training practices. In this thesis research, I will look at the development and application of VR-based immersive training games for two particular cases: 1. Post hand surgery rehab; and, 2. Training for Social determinants of health (SDOH) …
High Security Cognitive Radio Network Via Instantaneous Channel Information, Kaiyu Huang
High Security Cognitive Radio Network Via Instantaneous Channel Information, Kaiyu Huang
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The cognitive radio network has been considered one of the most promising communication technologies for next generation wireless communication. One important aspect of cognitive radio network research is the so-called Primary User Authentication. Naturally, the primary user authentication in the cognitive radio network requires strong encryption. For the primary user identification, this dissertation provides a method which hides the user information in the header of the data frames with an underlay waveform. It is important to note that the underlay waveform will not bring redundancy data to the communication system. Using the synchronizing frequency as the underlay waveform carrier also …
Accelerating Reverse Engineering Image Processing Using Fpga, Matthew Joshua Harris
Accelerating Reverse Engineering Image Processing Using Fpga, Matthew Joshua Harris
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In recent decades, field programmable gate arrays (FPGAs) have evolved beyond simple, expensive computational components with minimal computing power to complex, inexpensive computational engines. Today, FPGAs can perform algorithmically complex problems with improved performance compared to sequential CPUs by taking advantage of parallelization. This concept can be readily applied to the computationally dense field of image manipulation and analysis. Processed on a standard CPU, image manipulation suffers with large image sets processed by highly sequential algorithms, but by carefully adhering to data dependencies, parallelized FPGA functions or kernels offer the possibility of significant improvement through threaded CPU functions. This thesis …
Static Evaluation Of Type Inference And Propagation On Global Variables With Varying Context, Ivan Frasure
Static Evaluation Of Type Inference And Propagation On Global Variables With Varying Context, Ivan Frasure
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Software reverse engineering (SRE) is a broad field with motivations ranging from verifying or documenting gordian source code files to understanding and reimplementing binary object files and executables. SRE of binaries is exceptionally compelling and challenging due to large amounts of information that can be lost in the compilation progress. A central area in SRE is type inference. Type inference is built around a fundamental step in understanding the behavior of a binary, recovering the types of data in the program. Type inference has many unique techniques in both static and dynamic type inference systems that have been implemented in …
Digital Instantaneous Frequency Measurement Receiver For Fine Frequency And High Sensitivity, Bilal Khudhur Abdulhammed Abdulhamed
Digital Instantaneous Frequency Measurement Receiver For Fine Frequency And High Sensitivity, Bilal Khudhur Abdulhammed Abdulhamed
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Wideband technology has been applied to many wide bandwidth applications when there is a need to send much different information in a short time from one point and received from another point in high precision and accuracy. A wideband receiver reports a signal without tuning if the signal is within the input bandwidth. The analog Instantaneous Frequency Measurement (IFM) receiver has been used for decades to cover a very wide input bandwidth and report one accurate frequency on a short pulse at a time. The digital IFM use a high sampling rate ADC to operate in a wide bandwidth, Hilbert …
Design And Manipulation Of A Power-Generating System With High-Temperature Fuel Cells For Hypersonic Applications, Jack Randolph Chalker
Design And Manipulation Of A Power-Generating System With High-Temperature Fuel Cells For Hypersonic Applications, Jack Randolph Chalker
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Current hypersonic vehicles tend to be incapable of producing onboard power with traditional generators due to their use of supersonic combusting ramjets (scramjets). Because of this, they seek additional energy sources for supporting advanced electronics or other auxiliary power-dependent devices while requiring elaborate thermal management systems to combat temperatures exceeding 700ºC. The incorporation of Solid Oxide Fuel Cell (SOFCs) stacks is an efficient solution, capable of generating large quantities of power through the use of natural fuel sources at high temperatures. Developments in this thesis include the design, construction, and support of a system operating at hypersonic-environment conditions with a …
Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher
Design And Implementation Of Periodic Unsteadiness Generator For Turbine Secondary Flow Studies, Nathan James Fletcher
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A primary source of periodic unsteadiness in low-pressure turbines is the wakes shed from upstream blade rows due to the relative motion between adjacent stators and rotors. These periodic perturbations can affect boundary layer transition, secondary flow, and loss generation. In particular, for high-lift front-loaded blades, the secondary flowfield is characterized by strong three-dimensional vortical structures. It is important to understand how these flow features respond to periodic disturbances. A novel approach was taken to generate periodic unsteadiness which captures some of the physics of turbomachinery wakes. Using stationary pneumatic devices, pulsed jets were used to generate disturbances characterized by …
Securing Modern Cyberspace Using A Multi-Faceted Approach, Yu Li
Securing Modern Cyberspace Using A Multi-Faceted Approach, Yu Li
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Security has become one of the most significant concerns for our cyberspace. Securing the cyberspace, however, becomes increasingly challenging. This can be attributed to the rapidly growing diversities and complexity of the modern cyberspace. Specifically, it is not any more dominated by connected personal computers (PCs); instead, it is greatly characterized by cyber-physical systems (CPS), embedded systems, dynamic services, and human-computer interactions. Securing modern cyberspace therefore calls for a multi-faceted approach capable of systematically integrating these emerging characteristics. This dissertation presents our novel and significant solutions towards this direction. Specifically, we have devised automated, systematic security solutions to three critical …
Blended Wing Design Considerations For A Next Generation Commercial Aircraft, Jay Abhilash Vora
Blended Wing Design Considerations For A Next Generation Commercial Aircraft, Jay Abhilash Vora
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The current aircraft design has not changed significantly in the last few decades. Growing environmental concerns and fuel prices are driving manufacturers to develop unconventional but efficient aircraft configurations. The blended wing body (BWB) configuration provides an alternate and more efficient means of subsonic travel. The BWB aircraft replaces the traditional wings and fuselage with hybrid wing shape where the fuselage and wings have integrated. Major aircraft manufacturers are researching the BWB concept incorporating electric propulsion for civil transport use. In this research a 300 passenger BWB aircraft aerodynamic shape is designed. This aircraft is used to assess the aerodynamic …
As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh
As-Manufactured Modeling Of A Mistuned Turbine Engine Compressor Evaluated Against Experimental Approaches, Daniel L. Gillaugh
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As-manufactured rotors behave quite differently than nominal, as-designed rotors due to small geometric and material property deviations in the rotor, referred to as mistuning. Traditional integrally bladed rotor (IBR) modeling approaches assume each blade is identical. State-of-the-art IBR dynamic response predictions can be accomplished using asmanufactured models (AMM) generated via optical topography measurements and mesh morphing. As-manufactured models account for geometric deviations occurring through the machining process, material deviations and field wear, allowing each blade to respond differently. Rotor designs are intended to avoid resonance crossings throughout an engine’s operating range, but total avoidance is challenging. This has led to …
Recognition Of Incomplete Objects Based On Synthesis Of Views Using A Geometric Based Local-Global Graphs, Michael Christopher Robbeloth
Recognition Of Incomplete Objects Based On Synthesis Of Views Using A Geometric Based Local-Global Graphs, Michael Christopher Robbeloth
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The recognition of single objects is an old research field with many techniques and robust results. The probabilistic recognition of incomplete objects, however, remains an active field with challenging issues associated to shadows, illumination and other visual characteristics. With object incompleteness, we mean missing parts of a known object and not low-resolution images of that object. The employment of various single machine-learning methodologies for accurate classification of the incomplete objects did not provide a robust answer to the challenging problem. In this dissertation, we present a suite of high-level, model-based computer vision techniques encompassing both geometric and machine learning approaches …
Differential Microrna Expression In Barrett's Esophagus Correlates With Regulation Of Posterior Homeotic Genes, Reilly June Clark
Differential Microrna Expression In Barrett's Esophagus Correlates With Regulation Of Posterior Homeotic Genes, Reilly June Clark
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Barrett’s Esophagus (BE) is characterized by the appearance of an intestinal-like epithelium in the distal esophagus. The molecular mechanisms behind BE development are unknown. BE is often preceded by Gastroesophageal Reflux Disease (GERD) and predisposes patients to esophageal adenocarcinoma (EAC). Due to the high mortality rate associated with EAC, BE patients are continuously monitored through upper endoscopy with biopsy for progression to low grade dysplasia (LGD), high grade dysplasia, and EAC. This monitoring technique poses numerous risks, so alternative surveillance and diagnostic techniques for BE pathogenesis are continually studied. microRNA biomarkers in BE pathogenesis may provide alternative means of diagnosis …
Retail Facility Layout Considering Shopper Path And Door Placement, Sagarkumar D. Hirpara
Retail Facility Layout Considering Shopper Path And Door Placement, Sagarkumar D. Hirpara
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The physical design of a retail store is known to influence the attitude and behavior of shoppers, in turn affecting the store’s performance. While literature in retail design has alluded to the impact of changes in department placements on impulse revenue, it has not accounted for the changes in the path of a shopper due to such modifications. Shopper path changes can alter a department’s visibility to the shoppers as they pass by, and such visibility eventually impacts that department’s impulse revenue. To address this gap, we study the retail facility layout problem by accounting for changes in the shopper …
Islands Of Fitness Compact Genetic Algorithm For Rapid In-Flight Control Learning In A Flapping-Wing Micro Air Vehicle: A Search Space Reduction Approach, Kayleigh E. Duncan
Islands Of Fitness Compact Genetic Algorithm For Rapid In-Flight Control Learning In A Flapping-Wing Micro Air Vehicle: A Search Space Reduction Approach, Kayleigh E. Duncan
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On-going effective control of insect-scale Flapping-Wing Micro Air Vehicles could be significantly advantaged by active in-flight control adaptation. Previous work demonstrated that in simulated vehicles with wing membrane damage, in-flight recovery of effective vehicle attitude and vehicle position control precision via use of an in-flight adaptive learning oscillator was possible. Most recent approaches to this problem employ an island-of-fitness compact genetic algorithm (ICGA) for oscillator learning. The work presented provides the details of a domain specific search space reduction approach implemented with existing ICGA and its effect on the in-flight learning time. Further, it will be demonstrated that the proposed …
Knowledge-Enabled Entity Extraction, Hussein S. Al-Olimat
Knowledge-Enabled Entity Extraction, Hussein S. Al-Olimat
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Information Extraction (IE) techniques are developed to extract entities, relationships, and other detailed information from unstructured text. The majority of the methods in the literature focus on designing supervised machine learning techniques, which are not very practical due to the high cost of obtaining annotations and the difficulty in creating high quality (in terms of reliability and coverage) gold standard. Therefore, semi-supervised and distantly-supervised techniques are getting more traction lately to overcome some of the challenges, such as bootstrapping the learning quickly. This dissertation focuses on information extraction, and in particular entities, i.e., Named Entity Recognition (NER), from multiple domains, …
Fault-Tolerant Mapping And Localization For Quadrotor Uav, Maximillian Andrew Gilson
Fault-Tolerant Mapping And Localization For Quadrotor Uav, Maximillian Andrew Gilson
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This research aims to accomplish three main tasks for a quadrotor UAV with mapping and navigation capabilities. Firstly, a Simultaneous Localization and Mapping (SLAM) system is developed utilizing a laser rangefinder an open source SLAM algorithm called GMapping. This system allows for mapping of the surrounding environment as well as localizing the position of the quadrotor, enabling position control. Secondly, several path planning algorithms were implemented and evaluated. This allows the quadrotor to navigate through the environment even in the presence of obstacles. Lastly, to compensate for possible faults in the SLAM measurements, a fault-tolerant control method is developed. Real-time …
Multifunctional Oxide Heterostructures For Next-Generation Tunable Rf/Microwave Electronics, Hyung Min Jeon
Multifunctional Oxide Heterostructures For Next-Generation Tunable Rf/Microwave Electronics, Hyung Min Jeon
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Recent advanced radio frequency (RF) microwave device demands for low power consumption, light weight, compact package, and high performance. To achieve the high performance, applying magnetic materials is becoming indispensable in many of those devices. Thus, the role of magnetism in those devices is important high-quality magnetic materials not only improves the performance of microwave devices but also opens opportunities in developing novel concepts of devices utilizing spin wave excitation, non-reciprocal wave propagation, and the electromagnetic coupling in multiferroic materials. Among all the others, manipulating magnetic properties in multiferroic material started a couple years ago. Multiferroic materials are a group …
Knowledge Graph Reasoning Over Unseen Rdf Data, Bhargavacharan Reddy Kaithi
Knowledge Graph Reasoning Over Unseen Rdf Data, Bhargavacharan Reddy Kaithi
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In recent years, the research in deep learning and knowledge engineering has made a wide impact on the data and knowledge representations. The research in knowledge engineering has frequently focused on modeling the high level human cognitive abilities, such as reasoning, making inferences, and validation. Semantic Web Technologies and Deep Learning have an interest in creating intelligent artifacts. Deep learning is a set of machine learning algorithms that attempt to model data representations through many layers of non-linear transformations. Deep learning is in- creasingly employed to analyze various knowledge representations mentioned in Semantic Web and provides better results for Semantic …
Effects Of Lubrication Starvation On Flash Temperature For Thermal Mixed Elastohydrodynamic Gear Contacts, Danielle D. Massé
Effects Of Lubrication Starvation On Flash Temperature For Thermal Mixed Elastohydrodynamic Gear Contacts, Danielle D. Massé
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Lubrication is provided to the gear trains in automotive and aerospace transmission systems to prevent mechanical contact through the formation of a full lubricant film, which in turn removes heat generated at the gear contact surfaces. When debris blocks the inlet nozzle, the flow of lubricant is restricted and mechanical components experience lubrication starvation. Under starved lubrication the temperatures of the contact surfaces become elevated which can lead to the formation of a weld between them, a catastrophic failure mode called scuffing. For spur gears, the occurrence of scuffing is due to high sliding in the vicinity of the root …
Exploring Two-Dimensional Graphene And Silicene In Digital And Rf Applications, Zhonghang Ji
Exploring Two-Dimensional Graphene And Silicene In Digital And Rf Applications, Zhonghang Ji
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Since the discovery of graphene, two-dimensional (2D) materials have attracted intensive interests in the past 15 years and there has been a growing interest in exploring new materials beyond graphene, such as silicene, germanene, etc. Numerous papers have been published to demonstrate their extraordinary electronic, optical, biological, and thermal properties which render broad applications in various fields. However, the absence of band gap in graphene and silicene prohibits their uses in digital applications. This dissertation reviews recent progress on band gap opening based on mono- and bi- layer silicene and presents a new silicon atomic structure which exhibits a 0.17 …
A Graphene/Rf Gas Sensor, Kathleen Louise Brockdorf
A Graphene/Rf Gas Sensor, Kathleen Louise Brockdorf
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Toxic chemicals have been used as chemical warfare agents since ancient times, but World War 1 saw the beginning of modern chemical proliferation. There are many methods of detecting these agents, but the combination of high sensitivity, specificity, fast response, and small form factor is difficult to achieve. More recently, graphene has been identified as a possible sensing material for ammonia and other substances. This research documents a novel method of using graphene as a chemical sensor, utilizing a radio-frequency approach to sensing. This approach utilizes all available information from the material, such as permittivity and conductivity, instead of simply …
Non-Deterministic Metamodeling For Multidisciplinary Design Optimization Of Aircraft Systems Under Uncertainty, Daniel L. Clark Jr.
Non-Deterministic Metamodeling For Multidisciplinary Design Optimization Of Aircraft Systems Under Uncertainty, Daniel L. Clark Jr.
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To make coupled multi-physics-informed design decisions, multidisciplinary analysis, design optimization and uncertainty quantification must be present to accurately represent the full system under investigation. Unfortunately, all of these processes are computationally demanding, requiring a large number of system evaluations with identified uncertain variables, and iterative system evaluations with respect to the design variables of interest. Surrogate or metamodels are used to alleviate the computational burden in both these design exploration activities by trading accuracy with efficiency. The primary objective of this dissertation is to develop a flexible surrogate modeling technique capable of quantifying the uncertainty of multidisciplinary systems in an …
Mixed Signal Detection, Estimation, And Modulation Classification, Yang Qu
Mixed Signal Detection, Estimation, And Modulation Classification, Yang Qu
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Signal detection, parameter estimation and modulation classification are widely applied to many areas and plays a very important role in civilian and military, such as bio-science, criminal psychology, communication engineering, radar system, electronic warfare and so on. In the civilian field, with the increasing number of wireless electronic devices and higher transmission data rate demand, the problem of spectrum congestion becomes more and more highlighted and urgent. In recent years, wireless industry has shown great interest in Cognitive Radio (CR) and Dynamic Spectrum Access (DSA) network, whose primary function is to use limited frequency bands to transmit own signals without …
Cmos Receiver Design For 802.11ac Standard Using Offline Calibrated Active Inductor Based Band Pass Filter In 90 Nm Technology, Shuo Li
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Wireless local area network is widely used in industry and people daily life. More and more mobile devices rely on this technology to perform data communication with 2.4 GHz and 5 GHz frequency band. As the development of CMOS technology is able to keep shrinking chip size and increasing circuit integration density, traditional on-chip passive inductor inefficient area consumption issue is becoming critical to receiver front end system design. In this dissertation, an active inductor-based band pass filter is studied and implemented with 90 nm technology. This active inductor design provides very small area consumption and larger quality factor compared …
An Investigation On Spur Gear Rolling Contact Fatigue Crack Initiation And Crack Propagation Under Ehl Condition, Vignesh Dharmajan
An Investigation On Spur Gear Rolling Contact Fatigue Crack Initiation And Crack Propagation Under Ehl Condition, Vignesh Dharmajan
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Pitting is a rolling contact fatigue phenomenon commonly observed in mechanical rolling elements, such as gears and bearings. In case of gear contacts, pitting usually takes place in the dedendum region, where both sliding and contact load are high. In this study, a model is developed to predict surface breaking crack formation fatigue lives, including both nucleation and propagation stages, for spur gear contacts operating under mixed elastohydrodynamic lubrication (EHL) condition. The model utilizes a gear load distribution model for tooth contact Analysis. A mixed EHL formulation is implemented to evaluate the surface normal pressure and tangential shear, incorporating the …