Digital Commons Network^™

Comparison Of The Thermal Stability In Equal-Channel-Angular-Pressed And High-Pressure-Torsion-Processed Fe–21cr–5al Alloy, Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank W. Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nanostructured Steels Are Expected to Have Enhanced Irradiation Tolerance and Improved Strength. However, They Suffer from Poor Microstructural Stability at Elevated Temperatures. in This Study, Fe–21Cr–5Al–0.026C (Wt%) Kanthal D (KD) Alloy Belonging to a Class of (FeCrAl) Alloys Considered for Accident-Tolerant Fuel Cladding in Light-Water Reactors is Nanostructured using Two Severe Plastic Deformation Techniques of Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT), and their Thermal Stability between 500–700 °C is Studied and Compared. ECAP KD is Found to Be Thermally Stable Up to 500 °C, Whereas HPT KD is Unstable at 500 °C. Microstructural Characterization Reveals that ECAP KD …

Static I-V Based Pim Evaluation For Spring And Fabric-Over-Foam Contacts, Kalkidan W. Anjajo, Yang Xu, Shengxuan Xia, Yuchu He, Haicheng Zhou, Hanfeng Wang, Jonghyun Park, Chulsoon Hwang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spring Clips and Fabric-Over-Foams (FOFs) Are Widely Used in Mobile Devices for Electrical Connection Purposes. However, the Imperfect Metallic Connections Tend to Induce Passive Intermodulation (PIM), Resulting in a Receiver Sensitivity Degradation, Known as RP Desensitization. Due to the Complexity of the PIM Characterization, there is Not Yet a Way to Evaluate PIM Performance using a Simple Setup for Environments Like Factories. in This Paper, a Current-Voltage (I-V) Behavior-Based PIM Evaluation Method is Proposed and Validated with Various Metallic Contacts and Contact Forces. the Test Results Demonstrated the Feasibility of the PIM Performance Evaluation based on the Measured Static I-V …

Microstructure And Residual Stress In Functionally Graded 316l Stainless Steel/Inconel 625 Alloys Fabricated By Direct Energy Deposition, Xinchang Zhang, Liang Wang, Frank W. Liou, Yang Ren, Cheng Sun

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Functionally graded materials (FGMs) provide a unique solution to combine distinct properties within a single component to enhance its overall performance. Understanding the microstructure and residual stress distribution is particularly important as the material dissimilarity in FGMs can result in high residual stress that affects the mechanical integrity of structural components. This work aims to study the microstructure and residual stress of additively manufactured FGMs and the effects of isothermal annealing. In this study, 316L stainless steel/Inconel 625 FGMs were built by direct energy deposition and characterized by optical and electron microscopy as well as synchrotron-based X-ray diffraction. Our study …

Incremental Development Model Using Vacant Buildings For Affordable Housing, Seogjae Choi, Boyoung Michelle Huh

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Vacant properties have increased and become a problem in cities in the US. Few studies addressed how to utilize vacant properties for affordable housing despite they can be a great resource for affordable housing. To improve affordable housing sustainability, researchers recommended incremental development because it can satisfy residents' dynamic demands over time and engage them in house design. This can be implemented by utilizing vacant buildings to maximize their potential for affordable housing. Through the literature review, critical sustainability criteria for affordable housing are yielded. This paper demonstrates how the incremental development of vacant buildings satisfies the critical sustainability criteria. …

Experimental Approach For Development Of A Powder Spreading Metric In Additive Manufacturing, M. Hossein Sehhat, Austin T. Sutton, Zane Yates, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Powder Spreading is a Vital Step of Powder-Based Additive Manufacturing (AM) Processes. the Quality of Spread Powder Can Considerably Influence the Properties of Fabricated Parts. Poorly Packed Powder Beds with High Surface Roughness Result in Printed Part Layers with Large Porosity and Low Dimensional Accuracy, Leading to Poor Mechanical Properties. Therefore, the Powder Spread ability and its Dependence on Process Parameters and Powder Characteristics Should Be Quantified to Improve the Efficiency of Powder-Based AM Methods. This Study Proposes a Novel Dimensionless Powder Spread Ability Metric that Can Be Commonly Used in Different Powder-Based AM Processes. the Quality of Spread …

Post-Consolidation Process For Modifying Microscale And Mesoscale Parameters Of 3d Printed Composite Materials, Arief Yudhanto, Alwaleed Aldhirgham, Eric Feron, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Advancements in additive manufacturing technology (3D printing) have enabled us to fabricate reasonably good parts using continuous fiber-reinforced matrix composites. Unfortunately, most of these 3D-printed composite parts inherently possess a large number of voids originating from the trapped air within and between molten composite beads during the deposition stage. Removing the voids has thus become a key challenge in attempts to apply 3D printed composite parts for fabricating stiff/strong load-bearing structures. Here, we employed a classical process, viz. compression molding, to post-consolidate 3D-printed continuous carbon fiber-reinforced polyamide (CFPA), and to investigate the implications in terms of microscale parameters (void content) …

Data Analytics Of Wettability Alteration With Surfactants In Carbonate Reservoirs, Ya Yao

Doctoral Dissertations

"Wettability alteration with surfactants has been widely applied to improve oil recovery in carbonate reservoirs. An effective surfactant huff-puff application design requires comprehensive guidelines about where, how, and when this method could be applied. Besides, traditional methods to design an effective application and optimize surfactant performance are dependent on extensive experiments and are time-consuming. This study is to assist in the design of surfactant huff-puff via statistical methods and machine learning techniques.

In this study, a dataset including 402 effective surfactant imbibition tests is established by collecting information from nearly 50 publications. The dataset provides a foundation for further data …

Essays On Conditional Heteroscedastic Time Series Models With Asymmetry, Long Memory, And Structural Changes, K C M R Anjana Bandara Yatawara

Doctoral Dissertations

"The volatility of asset returns is usually time-varying, necessitating the introduction of models with a conditional heteroskedastic variance structure. In this dissertation, several existing formulations, motivated by the Generalized Autoregressive Conditional Heteroskedastic (GARCH) type models, are further generalized to accommodate more dynamic features of asset returns such as asymmetry, long memory, and structural breaks. First, we introduce a hybrid structure that combines short-memory asymmetric Glosten, Jagannathan, and Runkle (GJR) formulation and the long-memory fractionally integrated GARCH (FIGARCH) process for modeling financial volatility. This formulation not only can model volatility clusters and capture asymmetry but also considers the characteristic of long …

Analyzing Spatio-Temporal Mechanisms Of Land Subsidence In The Parowan Valley, Utah, Usa, Jiawei Li, Ryan G. Smith, Katherine R. Grote

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Parowan Valley, Utah (USA), is an agricultural region experiencing rapid subsidence due to extensive groundwater extraction from aquifers with a significant portion of fine-grained sediments. To analyze the subsidence spatio-temporally, time-series Interferometric Synthetic Aperture Radar (InSAR) of 155 Sentinel-1 C-band scenes were processed. These data showed approximately 30 cm of ground subsidence in Parowan Valley from 2014 to 2020. Because of the high temporal sampling rate of the Sentinel-1 satellite (12-day cycle), it is possible to determine the seasonal changes of ground deformation and relate this to groundwater extraction. To better understand the relationship between ground deformation and groundwater extraction …

Microcrystalline Dolomite In A Middle Permian Volcanic Lake: Insights On Primary Dolomite Formation In A Non-Evaporitic Environment, Xin Jiao, Yi Qun Liu, Wan Yang, Hong Li, Zi Yuan Meng, Min Ru Zhao, Zhe Xuan Li

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Lacustrine dolomite nucleation commonly occurs in modern and Neogene evaporitic alkaline lakes. As a result, ancient lacustrine microcrystalline dolomite has been conventionally interpreted to be formed in evaporitic environments. This study, however, suggests a non-evaporitic origin of dolomite precipitated in a volcanic–hydrothermal lake, where hydrothermal and volcanic processes interacted. The dolomite occurs in lacustrine fine-grained sedimentary rocks in the middle Permian Lucaogou Formation in the Santanghu intracontinental rift basin, north-west China. Dolostones are composed mainly of nano-sized to micron-sized dolomite with a euhedral to subhedral shape and a low degree of cation ordering, and are interlaminated and intercalated with tuffaceous …

Finite Line Relief Well System Design For Dams And Levees, Andrew M. Keffer, Erich D. Guy, Katherine R. Grote

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An Analytical Method is Commonly Used to Design Relief Well Systems by Assuming the Well Line Extends an Infinite Distance Parallel to the Dam or Levee. This Assumption May Be Met in Some Cases, But When a Well Line is of Finite Length, This Can Severely Underestimate Excess Heads. Although These Consequences Have Been Historically Recognized, a Practical Graph-Based Analytical Approach for Finite Well Line Design Has Not Been Developed. Finite Well Lines Exist and Continue to Be Installed at Many Locations, So This Study Developed a Practical Design Method for Such Systems. Analytical Solutions and Numerical Models Were Used …

Electrical Resistivity Tomography Revealing Possible Breaching Mechanism Of A Late Pleistocene Long-Lasted Gigantic Rockslide Dam In Diexi, China, Lanxin Dai, Xuanmei Fan, Dan Wang, Fanyu Zhang, Ali P. Yunus, Srikrishnan Siva Subramanian, J. David Rogers, Hans Balder Havenith

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Landslide damming is a widespread phenomenon worldwide and significantly affects the evolution of fluvial landscapes. However, it is rarely witnessed from an antiquities perspective, and the case for observing their internal structure is challenging. We attempt to visualize the subsurface structure and understand the likely breaching mechanism of the late Pleistocene Diexi gigantic landslide dam (longevity of ~ 10 ka), using electrical resistivity tomography (ERT) method. Eight ERT measurements on the Diexi dam body revealed high resistivity zones near the periphery and lower resistivity zones in the middle portion of the profiles. Geomorphological mapping based on the LiDAR data determined …

The Taphonomic Character, Occurrence, And Persistence Of Upper Permian–Lower Triassic Plant Assemblages In The Mid-Paleolatitudes, Bogda Mountains, Western China, Robert A. Gastaldo, Mingli Wan, Wan Yang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Bogda Mountains, Xianjiang Uygur Autonomous Region, Western China, Expose an Uppermost Permian–Lower Triassic Succession of Fully Continental Strata Deposited Across Three Graben (Half Graben) Structures in the Mid-Paleolatitudes of Pangea. a Cyclostratigraphy Scheme Developed for the Succession is Subdivided into Three Low-Order Cycles (Wutonggou, Jiucaiyuan, Shaofanggou). Low-Order Cycles Are Partitioned into 1838 High-Order Cycles based on Repetitive Environmental Changes, and their Plant Taphonomic Character is Assessed in . 4700 M of High-Resolution, Measured Sections Distributed Across ~ 100 Km. Four Taphonomic Assemblages Are Represented By: Permineralized Wood (Both Autochthonous and Allochthonous), Megafloral Adpressions (?parautochthonous and Allochthonous) Identifiable to Systematic …

A Novel Technique For The Quantitative Determination Of Wettability Of A Severely Heterogeneous Tight Carbonate Reservoir, Saleh Al-Sayegh, Ralph E. Flori, Waleed Al-Bazzaz, Abdulaziz Abbas, Ali Qubian, Hasan Al-Saedi

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The objective of this study is to accurately measure the wettability contact angle of a cretaceous carbonate reservoir in a vertical well set-up known for as an unconventional tight carbonate oil reservoir. Also, to investigate the relative heterogeneity of these samples using digitally captured images; these images accurately capture natural pore-system in this carbonate rock samples and their wettability performance attributed towards building a vertical depth wettability/heterogeneity model. To capture, measure and model natural tight matrix static contact angle wettability in order to understand their new physics that will advance unconventional tight oil reservoir characterization. Entire vertical well depth reservoir …

Practical Imaging Applications Of Wettability Contact Angles On Kuwaiti Tight Carbonate Reservoir With Different Rock Types, Saleh Al-Sayegh, Ralph E. Flori, Waleed Al-Bazzaz, Sohaib Kholosy, Hasan Al-Saedi, Abdulaziz Abbas, Ali Qubian

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This study focuses on a tight carbonate reservoir which is located in Northern Kuwait and is classified as an unconventional reservoir. A practical imaging technique of wettability contact angle (θ°) presents "big data" as well as relative-permeability (Krw and Kro) measurements. Also, modeling, through rock image technology, the vast well-documented grain/pore boundary morphology available inside fresh rock fragments have achieved good results. Conventional laboratory relative-permeability experiments are expensive and time-consuming. This study introduces a novel method to measure/calculate relative permeability through fast, less expensive, non-destructive, and environmentally friendly techniques of imaging technology. One tight carbonate reservoir is selected, imaged, processed, …

Drainage And Sedimentary Response Of The Northern Andes And The Pebas System To Miocene Strike-Slip Tectonics: A Source To Sink Study Of The Magdalena Basin, S. Zapata, L. Calderon-Diaz, C. Jaramillo, Francisca Oboh-Ikuenobe, J. C. Piedrahita, M. Rodríguez-Cuevas, A. Cardona, E. R. Sobel, M. Parra, V. Valencia, A. Patiño, J. S. Jaramillo-Rios, M. Flores, J. Glodny

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Miocene strike-slip tectonics was responsible for creating and closing short-lived (ca. 6 Ma) passages and the emergence of isolated topography in the Northern Andes. These geological events likely influenced the migration and/or isolation of biological populations. To better understand the paleogeography of the Miocene hinterland and foreland regions in the Northern Andes, we conducted a source-to-sink approach in the Magdalena Basin. This basin is located between the Central and Eastern Cordilleras of Colombia and contains an ample Miocene record, which includes Lower Miocene fine-grained strata and Middle Miocene to Pliocene coarsening-up strata. Our study presents a new data set that …

Sedimentological And Geochemical Characterization Of A Varved Sediment Record From The Northern Neotropics, Edward Duarte, Jonathan Obrist-Farner, Susan R.H. Zimmerman, Erik T. Brown, Robert Brown

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Annually resolved sedimentological records (including annual varves) can be used to develop precise chronologies for key climatic and tectonic events. Varved records, however, are most common in high latitude lakes, resulting in a spatial bias with respect to annually resolved records in tropical regions. Here we report on the sedimentology of two sediment cores from Lake Izabal, eastern Guatemala, that contain a well-preserved thinly laminated section spanning ca. 2200 years of the mid-Holocene. We integrate radiocarbon age-depth modeling, sedimentological observations, laminae counting, µX-ray fluorescence scanning, and multivariate statistical analyses to constrain the nature and chronology of the laminations. Our sedimentological …

Impact Of Composition And Salinity On Swelling And Gel Strength Of Poly (Acrylamide-Co-Acrylic Acid) Preformed Particle Gel, Ahmed Ben Ali, Reem Elaf, Mohammed Saad, Ibnelwaleed A. Hussein, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The effects of various material compositions and reservoir environments on the ultimate strength and swelling kinetics of a commercial preformed particle gel (PPG) have been investigated. This study used different ratios of acrylamide and acrylic acid copolymers with a specific crosslinker concentration. Results have indicated that increasing the acrylic acid proportion enhances the PPGs' ability to swell but weakens their network structure. In contrast, increasing the crosslinker content decreases the swelling ratio and increases the gel strength. The highest equilibrium swelling capacity among the six preformed particle gel samples was obtained for PPG2, which has the highest acrylic acid amount …

Prediction Of Single Proppant Terminal Settling Velocity In High Viscosity Friction Reducers By Using Artificial Neural Networks And Xgboost, Xiaojing Ge, Rong Lu, Ghith Biheri, Abdulmohsin Imqam, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

High viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. The settling velocity of the proppant is one of the key outputs to describe their proppant transport capability. However, it is influenced by many factors such as fluid properties, proppant properties, and fracture properties. Many empirical/physics-based models and correlations to predict particle settling velocity have been developed. However, they are usually based on certain assumptions and have applicable limits. In contrast, machine learning models can be considered as a black box. The objective of this …

Transport And Plugging Performance Evaluation Of A Novel Re-Crosslinkable Microgel Used For Conformance Control In Mature Oilfields With Super-Permeable Channels, Adel Alotibi, T. Song, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Preformed particle gels (PPG) have been widely applied in oilfields to control excessive water production. However, PPG has limited success in treating opening features because the particles can be flushed readily during post-water flooding. We have developed a novel micro-sized Re-crosslinkable PPG (micro-RPPG) to solve the problem. The microgel can re-crosslink to form a bulk gel, avoiding being washed out easily. This paper evaluates the novel microgels' transport and plugging performance through super-permeable channels. Micro-RPPG was synthesized and evaluated for this study. Its storage moduli after fully swelling are approximately 82 Pa. The microgel characterization, self-healing process, transportation behavior, and …

Laboratory Investigation Of Regained Rock Permeability Using High Viscosity Friction Reducer In Comparison To Linear Guar Fracture Fluids, Ghith Biheri, Abdulmohsin Imqam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Hydraulic fracturing is a method employed for extracting oil and gas from unconventional reservoirs by pumping a mixture of water, sand, and additives into the reservoirs to fracture oil formations. A high viscosity friction reducer (HVFR) based on polyacrylamide is a popular chemical that has been employed recently during hydraulic fracturing treatments to help transport proppant and to reduce friction. However, the use of HVFRs at high concentrations, especially in regions with high concentration levels of total dissolved solids (TDS), has raised concerns over the possibility of formation damage. In this research, a new type of HVFR was investigated for …

The Influence Of Tropical Atlantic Sea-Surface Temperatures And The North Atlantic Subtropical High During The Maya Droughts, Derek K. Gibson, Jonathan Obrist-Farner, Brooke A. Birkett, Jason H. Curtis, Melissa A. Berke, Peter M.J. Douglas, Prudence M. Rice, Jeremy Maurer

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The frequency and duration of Late-Holocene hydrologic extremes in northern Guatemala were investigated using multiple sedimentological and geochemical proxies preserved in a sediment core collected from Lake Petén Itzá. A general trend of increasing aridity in the Maya Lowlands during the past 2000 years was punctuated by several multidecadal- to centennial-scale drought events recorded in the Petén Itzá sediments. In particular, the period spanning the Maya Terminal Classic Period and the Medieval Climate Anomaly (MCA), between 800 and 1300 CE, was marked by several extreme droughts and included the driest conditions of the past 2000 years between 950 and 1100 …

Ongoing Fragmentation Of The Subducting Cocos Slab, Central America, Tu Xue, Diandian Peng, Kelly H. Liu, Jonathan Obrist-Farner, Marek Locmelis, Stephen S. Gao, Lijun Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Fundamental to plate tectonics is the subduction of cold and mechanically strong oceanic plates. While the subducted plates are conventionally regarded to be impermeable to mantle flow and separate the mantle wedge and the sub slab region, isolated openings have been proposed. by combining new shear wave splitting measurements with results from geodynamic modeling and recent seismic tomography and geochemical observations, we show that the upper ~200 km of the Cocos slab in northern Central America is intensively fractured. the slab there is strong enough to produce typical arc volcanoes and Benioff Zone earthquakes but allows mantle flow to traverse …

Sentiment Strength And Topic Recognition In Sentiment Analysis, Esi A.R. Adeborna

Masters Theses

"Current sentiment analysis methods focus on determining the sentiment polarities (negative, neutral or positive) in users’ sentiments. However, in order to correctly classify users’ sentiments into their right polarities, the strengths of these sentiments must be considered. In addition to classifying users’ sentiments into their correct polarities, it is important to determine the sources and topics under which users’ sentiments fall. Sentiment strength helps as to understand the levels of customer satisfaction toward products and services. Sentiment topics on the other hand, helps to determine the specific product/service areas associated with user sentiments. This paper proposes two sentiment analysis approaches. …

Designing Exterior Lighting For Safety And Comfort While Minimizing Light Pollution, Energy Consumption, And Cost, Stephen Michael Simmons

Masters Theses

"Artificial light at night brings many benefits to society. However, these benefits do not come without costs. One environmental issue that is often overlooked in the design of public spaces and infrastructure is light pollution. At the expense of large amounts of energy, light pollution causes numerous harmful effects on human health, ecosystems, and the night sky. Today, the problem is becoming more widespread, especially with the increasing use of bright, white LED luminaires. Thus, it is imperative for designers and engineers to create smarter lighting designs that not only allow for safety and comfort at night but also promote …

Mat: Genetic Algorithms Based Multi-Objective Adversarial Attack On Multi-Task Deep Neural Networks, Nikola Andric

Masters Theses

"Vulnerability to adversarial attacks is a recognized deficiency of not only deep neural networks (DNNs) but also multi-task deep neural networks (MT-DNNs) that attracted much attention in the past few years. To the best of our knowledge, all multi-task deep neural network adversarial attacks currently present in the literature are non-targeted attacks that use gradient descent to optimize a single loss function generated by aggregating all loss functions into one. On the contrary, targeted attacks are sometimes preferred since they give more control over the attack. Hence, this paper proposes a novel targeted multi-objective adversarial ATtack (MAT) based on genetic …

Dynamic Discounted Satisficing Based Driver Decision Prediction In Sequential Taxi Requests, Sree Pooja Akula

Masters Theses

"Ridesharing platforms rely on connecting available taxi drivers to potential passengers to maximize their revenue. However, predicting the stopping decision made by every driver, i.e., the final task performed during a given day, is crucial to achieving this goal. Unfortunately, little research has been done on predicting drivers’ stopping decisions, especially when they deviate from expected utility maximization behavior. This research proposes a Dynamic Discounted Satisficing (DDS) heuristic to model and learn the task at which human agents will stop working for that day, assuming that the human agents are taking sequential decisions based on their preference order. We apply …

Selecting Consolidation Procedures For Making Concrete Specimens, Paige Marie Toebben

Masters Theses

"The goal of this research was to reevaluate ASTM C31 Standard Practice for Making and Curing Concrete Test Specimens in the Field, as well as deepen our understanding of the relationship between the consolidation process, concrete composition, and workability. An improved understanding of this area will help to reduce variability in concrete quality. The project involved evaluating the effect of different consolidation methods on concrete specimens with changing levels of workability. To do this, concrete cylinders were created with varying viscosities by adjusting the water-to-cement ratio (w/c) and water-reducing agent. More cylinders were created with varying paste volumes while keeping …

Area Average Surface Transfer Coefficient In Unit Cell Geometries, Benjamin Gabriel Mackey

Masters Theses

"Honeycombs, metal foams, and lattice structures all provide a way to increase heat transfer due to better fluid mixing and larger surface area. Specifically, lattice structures can be a great way to provide heat transfer enhancement due to the ability to customize and optimize the unit cell geometry. In this research, a novel yet simple unit cell geometry is chosen for study. Four different configurations are tested in a lower Reynolds number range, 300–1800: single unit cell, two-unit cells in series, three-unit cells in series, and a 3x3 unit cell array. The Sherwood number of each configuration is found by …

Boosting Snr Of Cascaded Fbgs In A Sapphire Fiber Through A Rapid Heat Treatment, Farhan Mumtaz, Hanok Tekle, Bohong Zhang, Jeffrey D. Smith, Ronald J. O'Malley, Rex Gerald, Jie Huang

PSMRC Faculty Research

This Letter reports the performance of femtosecond (fs) laser-written distributed fiber Bragg gratings (FBGs) under high-temperature conditions up to 1600°C and explores the impact of rapid heat treatment on signal-to-noise ratio (SNR) enhancement. FBGs are essential for reliable optical sensing in extreme temperature environments. Comprehensive tests demonstrate the remarkable performance and resilience of FBGs at temperatures up to 1600°C, confirming their suitability for deployment in such conditions. The study also reveals significant fringe visibility improvements of up to ∼10 dB on a 1-m-long sapphire optical fiber through rapid heat treatment, representing a first-time achievement to the best of our knowledge. …