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Full-Text Articles in Engineering

Effect Of Admixtures On Rapid Hardening, Self-Consolidating Concrete, Haley Johnson Jan 2024

Effect Of Admixtures On Rapid Hardening, Self-Consolidating Concrete, Haley Johnson

Theses and Dissertations--Civil Engineering

Self-consolidating, rapid-hardening concrete is a sought-after product in the market now, however the effects of admixtures on fresh and hardened concrete rheology are still uncertain. This study aims to create a self-consolidating concrete (SCC) using calcium sulfoaluminate (CSA) cement for its rapid-hardening properties, and tests two set time retarders and two viscosity-modifying admixtures (VMAs) to determine how they affect the properties of concrete. The properties studied in this thesis are workability, viscosity, set times, air content, compressive strength, and freeze-thaw resistance of self-consolidating concrete. It was found that tartaric acid creates a very workable SCC with consistent results regardless of …


Quantitative Sustainable Design Of Urban Tree Soil Cells For Stormwater Management, Jamaya Wilson Jan 2024

Quantitative Sustainable Design Of Urban Tree Soil Cells For Stormwater Management, Jamaya Wilson

Theses and Dissertations--Civil Engineering

Urban trees are critical assets to cities around the world. They act as a green infrastructure system to provide various environmental, economic and social benefits to their surrounding environments. However, the quality of life of urban trees is severely threatened by uncontrolled urbanization and climate change. The compaction of urban soils to meet the structural stability requirements for buildings and pavements directly restricts tree growth. Soil cells are green infrastructure placed in tree wells to transfer active and static loads to pavements. This allows for reduced soil compaction and increased tree root expansion. However, because the technology is still in …


Understanding The Construction Workforce Needs Of The Future: Technology, Skills, Diversity, Bassam Ramadan Jan 2024

Understanding The Construction Workforce Needs Of The Future: Technology, Skills, Diversity, Bassam Ramadan

Theses and Dissertations--Civil Engineering

The U.S. construction industry stands at a crossroads. The looming age cliff is about to present its most serious challenges yet, coinciding with a shortage of qualified skilled professionals. As the demands of the construction industry continue to grow, it continues to lack the manpower to meet those demands. In order to meet the rising demands of construction needs in the near future, the construction industry needs to focus on improving workforce performance and productivity, and increasing the size of the construction labor force. Existing research highlights the importance of technological adoption and workforce skills, and that gender and ethnic …


Development Of A Particulate Matter Sensor Network For Air Quality Monitoring In Indoor Settings And In Mines, Abdulrahman Bani Jan 2024

Development Of A Particulate Matter Sensor Network For Air Quality Monitoring In Indoor Settings And In Mines, Abdulrahman Bani

Masters Theses

"The importance of indoor air quality (IAQ), especially concerning particulate matter (PM), has become increasingly recognized due to its substantial impact on public health. Individuals spend a significant portion of their time indoors, where PM concentrations can exceed that of outdoors, leading to potential adverse health effects ranging from immediate irritation to long-term respiratory and cardiovascular diseases. The dynamic nature of indoor environments, combined with the diversity of PM sources, presents considerable challenges for effective IAQ monitoring and management. Traditional approaches to IAQ assessment often fall short, lacking the granularity and immediacy required to address these challenges adequately.

This abstract …


Evaluating Friction Characteristics Of High Friction Surface Treatment Application Under Varied Polishing And Slippery Conditions, Alireza Roshan, Magdy Abdelrahman Jan 2024

Evaluating Friction Characteristics Of High Friction Surface Treatment Application Under Varied Polishing And Slippery Conditions, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The frictional attributes of high friction surface treatment (HFST) play a crucial role in ensuring optimal traffic safety, particularly in wet weather conditions. Friction consists of two important components: adhesion and hysteresis. This research focuses on evaluating these essential factors in HFST using two different aggregates and two distinct sizes by considering various abrasion and polishing methods. To isolate these components for assessment, testing was carried out under various slippery conditions, including dry, wet with water, and wet with water + soap. The inclusion of liquid hand soap in the test procedure effectively minimized or even eliminated the adhesion component's …


Agent-Based Modeling For Understanding Incentives Associated With Distributed Solar Generation, Gasser Ali, Islam H. El-Adaway Jan 2024

Agent-Based Modeling For Understanding Incentives Associated With Distributed Solar Generation, Gasser Ali, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Distributed solar generation (DSG), such as residential photo-voltaic (PV) solar panels, offers many benefits to consumers and can improve the sustainability and resilience of the electric power infrastructure. As such, many local and national authorities implemented policy incentives, such as rebates and loans with reduced interests, to promote the adoption of DSG. However, the increasing penetration of DSG is creating new obstacles for system operators due to the uncertainty in forecasting electrical power demand. There is a need to investigate how incentives affect DSG adoption. To achieve that goal, a complex system-of-systems (SoS) model is developed using agent-based modeling (ABM). …


System Dynamics Modeling For Investigating The Retention Of Skilled Labor In The Construction Market, Tamima Elbashbishy, Islam H. El-Adaway Jan 2024

System Dynamics Modeling For Investigating The Retention Of Skilled Labor In The Construction Market, Tamima Elbashbishy, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Limited skilled labor has been one of the greatest challenges facing the construction industry, especially after COVID. In 2019, around 80% of contractors in the US reported problems in hiring enough skilled workers. Labor retention has been one of the major contributors to skilled labor shortages in construction. The goal of this paper is to study the impact of key construction industry characteristics and economic conditions on skilled labor shortages. This goal is achieved by simulating the flow of skilled workers throughout the construction industry. To this end, a system dynamics (SD) model was developed to represent skilled labor and …


Investigating Price Fluctuation Transmission Among Construction Materials, Mohamad Abdul Nabi, Islam H. El-Adaway, Rayan H. Assaad Jan 2024

Investigating Price Fluctuation Transmission Among Construction Materials, Mohamad Abdul Nabi, Islam H. El-Adaway, Rayan H. Assaad

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Generally, Fluctuation In One Material's Price Can Cause A Series Of Chain Reactions In The Supply Chain System, Known As Price Fluctuation Transmission, As All Materials Are Interconnected And Interrelated. None Of The Previous Studies Have Investigated Price Fluctuation Transmission Among All Construction Materials. This Paper Aims To Fill This Gap In Knowledge. The Authors Collected Producer Price Index (PPI) Data For 16 Construction Materials, Modeled The Relationship Between Each Pair Of Materials Using Vector Autoregression Technique, And Validated The Causality Using Granger Causality Test. Network Analysis Was Performed To Identify The Price Fluctuation Transmission Capacity, Susceptibility, And Intermediatory Capacity …


Post-Fire Hydrologic Analysis: A Tale Of Two Severities, Kendra Fallon, Shawn J. Wheelock, Mojtaba Sadegh, Jennifer L. Pierce, James P. Mcnamara, Megan Cattau, Victor R. Baker Jan 2024

Post-Fire Hydrologic Analysis: A Tale Of Two Severities, Kendra Fallon, Shawn J. Wheelock, Mojtaba Sadegh, Jennifer L. Pierce, James P. Mcnamara, Megan Cattau, Victor R. Baker

Civil Engineering Faculty Publications and Presentations

Addressing post-fire impacts largely depends on burn “severity.” A singular severity classification that encompasses the holistic effects of fire on all ecosystem processes does not currently exist. Lumping vegetation burn severity and soil burn severity into one metric, or using them interchangeably, can induce large inaccuracies and uncertainties in the intended ecosystem response to forcing. Often, burn “severity” reflects fire impacts on vegetation, which can be measured through remote sensing. Vegetation burn severity is likely more apropos for ecological research, whereas soil burn severity is more relevant for hydrological analyses. This paper reviews different remotely sensed vegetation severity products currently …


Strategies To Mitigate Efflorescence In Walls Constructed Using Clays Bricks; A Review Article, Marwa Abdulkareem. Anber, Soran Abdulrahman Ahmad, Naros Rahman Mahmoud, Kawan Fuoad. Kayani, Mohammed Ali Abdulrehman Jan 2024

Strategies To Mitigate Efflorescence In Walls Constructed Using Clays Bricks; A Review Article, Marwa Abdulkareem. Anber, Soran Abdulrahman Ahmad, Naros Rahman Mahmoud, Kawan Fuoad. Kayani, Mohammed Ali Abdulrehman

Al-Esraa University College Journal for Engineering Sciences

The construction of buildings, especially residential housing for communities, is a significant industry on a global scale. Masonry units such as bricks, blocks, and stones are often utilized materials. Bricks are highly regarded because to their widespread availability, cost-effectiveness, and excellent insulating capabilities. Nevertheless, the presence of efflorescence presents a difficulty in the construction of brick walls. Efflorescence refers to the process in which salts move to the outer layer of the brick, resulting in the formation of white deposits and negatively impacting its visual appeal. Efflorescence is caused by various circumstances, such as the existence of salts in bricks, …


The Importance Of Cryptography In Cloud Computing, Saja Alaam Talib Jan 2024

The Importance Of Cryptography In Cloud Computing, Saja Alaam Talib

Al-Esraa University College Journal for Engineering Sciences

Cloud computing has grown as a widely accepted concept simultaneously, as the alarms for the security of data and information. This paper seeks to establish the comprehensive roles of cryptography in tackling these issues in the Cloud environment. The study begins with the historical background of cryptography and then moves on to analyze trends in information technology before discussing on the challenges to security in cloud computing. The goal of its publication is to highlight the importance of using cryptographic technologies for the protection of information confidentiality, its integrity and compliance. The combination of literature review and the case study …


Investigating Emerging Technologies In Civil Structural Health Monitoring: Generative Artificial Intelligence And Virtual Reality, Furkan Luleci Jan 2024

Investigating Emerging Technologies In Civil Structural Health Monitoring: Generative Artificial Intelligence And Virtual Reality, Furkan Luleci

Graduate Thesis and Dissertation 2023-2024

Condition assessment of civil engineering infrastructure systems is of growing importance as they face aging and degradation due to both human-made activities and environmental factors. Nevertheless, challenges persist in data collection, leading to "data scarcity", and the need for frequent site visits in inspections, presenting significant obstacles in the assessment of the civil infrastructure systems. This dissertation aims to overcome these challenges by exploring the potential of two emerging technologies: Generative Artificial Intelligence (AI) and Virtual Reality (VR). In tackling the issue of data scarcity, the research question revolves around how Generative AI can be utilized to mitigate data collection-related …


Termite Gut Microbe (Tav5) Application To Pulp & Paper Wastewater And Sugarcane Bagasse: Enhancing Lignin Degradation And Methane Generation During Anaerobic Digestion, Doreen Ntiamoah-Asare, Melanie Sattler Ph.D, P.E. Jan 2024

Termite Gut Microbe (Tav5) Application To Pulp & Paper Wastewater And Sugarcane Bagasse: Enhancing Lignin Degradation And Methane Generation During Anaerobic Digestion, Doreen Ntiamoah-Asare, Melanie Sattler Ph.D, P.E.

Civil Engineering Dissertations - Archive

TAV5 is a bacterium strain of the family Opitutaceae from Termite-Associated Verrucomicrobium isolated from the hindgut of Reticulitermes Flavipes, the most common subterranean termite in North America. The genome of TAV5 contains genes coding for enzymes that could structurally modify lignin.

Pulp & paper wastewater and Sugarcane bagasse contain high levels of cellulose (44-46%) and hemicellulose (27-32% ), as well as lignin (17-23%) which is recalcitrant to biodegradation. The lignin tend to shield the cellulose and hemicellulose making them inaccessible for biodegradation.

TAV5 can breakdown lignin, making the cellulose and hemicellulose accessible to microorganisms for biodegradation into methane generation for …


Development Of A Real-Time Warning System For Bridge Icing Using Time Domain Reflectometry, Taryn Dilorenzo Jan 2024

Development Of A Real-Time Warning System For Bridge Icing Using Time Domain Reflectometry, Taryn Dilorenzo

Civil Engineering Dissertations - Archive

Treacherous driving conditions are a safety concern during the winter season where icing on roadways and bridges is of particular concern. The use of sensors to detect the presence or potential of surface ice formation is essential for efficient and effective winter road maintenance. However, there is a lack of ice detection systems that combine robust sensors, active warning signs and an ice detection algorithm that is reliable and economical. This study presents an innovative sensor that uses dielectric sensing to detect the onset of ice formation on a bridge deck. The sensor combines an automatic algorithm for ice detection …


Streamlining Public Engagement In Transportation Projects Using Text Analytics, Alireza Shamshiri Jan 2024

Streamlining Public Engagement In Transportation Projects Using Text Analytics, Alireza Shamshiri

Civil Engineering Dissertations - Archive

Infrastructure projects impact a broad range of stakeholders, particularly local communities, whose engagement is critical for successful outcomes. Despite the importance of public engagement in these projects, traditional methods of capturing and analyzing public opinion often fail to fully represent the diverse, genuine perspectives involved. This has led to conflicts between community members and project sponsors. On the other hand, despite advancements in text analytics, including natural language processing (NLP) and its subfields such as topic modeling, sentiment analysis, and neural networks, their functionalities and effectiveness in analyzing public opinion in the domain of infrastructure projects have not been fully …


Roles Of Vegetation On Soil Moisture Dynamics In Transitional Climates- Lessons From Improving Phenology Representation In Land Surface Model And Retrieval Algorithm, Farhad Hassani Jan 2024

Roles Of Vegetation On Soil Moisture Dynamics In Transitional Climates- Lessons From Improving Phenology Representation In Land Surface Model And Retrieval Algorithm, Farhad Hassani

Civil Engineering Dissertations - Archive

Soil moisture is a critical component of the terrestrial water and energy cycles, influencing key hydrological and atmospheric processes such as infiltration, runoff generation, evapotranspiration, and atmospheric boundary layer dynamics. Accurate representation of soil moisture is essential for reliable hydrological modeling, drought monitoring, and seasonal to sub-seasonal (S2S) weather forecasting. Vegetation significantly affects soil moisture dynamics through processes like transpiration, canopy interception, and root water uptake, especially in transitional climates where conditions fluctuate between arid and humid states. However, errors in vegetation phenology representation can lead to substantial biases in soil moisture estimates within land surface models (LSMs) and satellite …


Development And Application Of Teems (Telecommuting Expectation Models): Predicting Post-Pandemic Telecommuting Choice And Frequency Using Machine Learning Models, Aiswarya Acharath Mohanakrishnan Jan 2024

Development And Application Of Teems (Telecommuting Expectation Models): Predicting Post-Pandemic Telecommuting Choice And Frequency Using Machine Learning Models, Aiswarya Acharath Mohanakrishnan

Civil Engineering Dissertations - Archive

Telecommuting, increasingly prevalent in today's workforce, has gained significant momentum amid the pandemic-induced shift towards remote work. It altered the travel behavior of workers and their travel patterns. This evolution prompts a reevaluation of worker travel behavior, necessitating adjustments in travel demand modeling to optimize transportation planning and service provision. Using the commuter’s data from a typical pre-pandemic workday to model the travel demand of weeks or years in the future is outdated. In designing transportation systems for the future, Metropolitan Planning Organizations (MPOs) will thus need to account for change in work trips due to telecommuting, and how this …


Moisture And Glass Transition Temperature Kinetics From Long Term Hygrothermal Aging Of Carbon/Epoxy Composites, Behnaz Hassanpour Jan 2024

Moisture And Glass Transition Temperature Kinetics From Long Term Hygrothermal Aging Of Carbon/Epoxy Composites, Behnaz Hassanpour

Civil Engineering Dissertations - Archive

The durability of fiber reinforced polymer composites used in civil infrastructure rehabilitation has become increasingly critical, especially under long-term hygrothermal aging conditions. This study focuses on the results of long-term (up to 6 years) hygrothermal aging of wet layup carbon/epoxy composites and investigates the effects of moisture, as well as accelerated aging at elevated temperatures with varying thicknesses and fabric areal weights. The primary objective is to establish a comprehensive understanding of moisture uptake kinetics and its subsequent effects on the glass transition temperature (Tg), mechanical performance, and the resulting implications for material durability. Four papers form …


Environmental Sustainability, Healthcare Workers And Healthcare Students: A Literature Review Of Attitudes And Learning Approaches, Pamela R. Mccauley, Kavita Mathur, Reza Kamali Miab, Nina Cohen, Kedena Henriques-Thompson, Jyo Gopinath Jan 2024

Environmental Sustainability, Healthcare Workers And Healthcare Students: A Literature Review Of Attitudes And Learning Approaches, Pamela R. Mccauley, Kavita Mathur, Reza Kamali Miab, Nina Cohen, Kedena Henriques-Thompson, Jyo Gopinath

Health Professions Education

Purpose: Today, increased attention has been placed on the healthcare industry and its workers in the wake of the global COVID-19 pandemic. Increases in facemask production, personal protective equipment, and the number of patients admitted into hospitals have resulted in a sharp rise in medical waste and environmental concerns. This has led to a greater interest by the research community to study the type of training and education that healthcare workers and students receive which could facilitate the implementation of sustainability activities during their work.

Design/Methodology: We have conducted a literature review (2010 to 2024) on healthcare worker …


A Concept Of Producing Aluminum In-Situ On The Moon Through Molten Salt Electrolysis, Jacob N. Ortega, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daniel Stutts, Daoru Han Jan 2024

A Concept Of Producing Aluminum In-Situ On The Moon Through Molten Salt Electrolysis, Jacob N. Ortega, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daniel Stutts, Daoru Han

Materials Science and Engineering Faculty Research & Creative Works

This paper presents a concept of producing aluminum in-situ on the lunar surface, namely, the Lunar In-Situ Aluminum Production through Molten Salt Electrolysis (LISAP-MSE) method developed at Missouri University of Science and Technology. This paper aims to demonstrate the use of electro-deoxidation to reduce aluminum oxide (i.e., alumina) into aluminum and oxygen gas via electrolysis in a molten salt bath for the production of aluminum on the Moon. It is shown that with a steady supply of hydrogen chloride, this in-situ resource utilization (ISRU) method could supply several necessary materials consumed in the electro-deoxidation process except hydrogen chloride to produce …


Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Natalie Mendez Jan 2024

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Natalie Mendez

Cal Poly Humboldt theses and projects

The integration of Indigenous and Western science plays an essential role in Tribally led collaborations for land management. This process of woven sciences is rooted in reciprocal relations and partnerships guided by Tribal Nations. Our cohort was invited by Wiyot Tribal Representatives to investigate a culvert located within the wetlands of Mouralherwaqh— a parcel of land reacquired by the Wiyot Tribe in 2022. This document seeks to share our experience and analysis as part of the Wiyot Tribe’s broader journey in navigating ecocultural restoration projects within Mouralherwaqh. The four community interests we investigated for the wetland crossing included a resized …


Unveiling Travel Patterns With The Next-Generation Passive Mobile Origin And Destination (Od) Data From The National Household Travel Survey, Muthumari Anbumani, Srinivas S. Pulugurtha Jan 2024

Unveiling Travel Patterns With The Next-Generation Passive Mobile Origin And Destination (Od) Data From The National Household Travel Survey, Muthumari Anbumani, Srinivas S. Pulugurtha

Kentucky Transportation Center Presentations

No abstract provided.


Extrinsic Calibration Of 3d Lidar Using Sphere Targets And Target-Centered Gps, Xinyu Cao, Sean Brennan Jan 2024

Extrinsic Calibration Of 3d Lidar Using Sphere Targets And Target-Centered Gps, Xinyu Cao, Sean Brennan

Kentucky Transportation Center Presentations

No abstract provided.


Motorcycle Crash Risk And Risk-Taking Behaviors: An Analysis For Costa Rica, Jonathan Aguero-Valverde, Jessica Álvarez López, Darío Vargas Aguilar Jan 2024

Motorcycle Crash Risk And Risk-Taking Behaviors: An Analysis For Costa Rica, Jonathan Aguero-Valverde, Jessica Álvarez López, Darío Vargas Aguilar

Kentucky Transportation Center Presentations

No abstract provided.


Analysis Of Factors Associated With The Frequency Of Turning Vehicle-Bicycle Crashes At Signalized Intersections, Faria Raha, Brendan J. Russo, Anthony M. Eschen, Steven R. Gehrke, Edward J. Smaglik Jan 2024

Analysis Of Factors Associated With The Frequency Of Turning Vehicle-Bicycle Crashes At Signalized Intersections, Faria Raha, Brendan J. Russo, Anthony M. Eschen, Steven R. Gehrke, Edward J. Smaglik

Kentucky Transportation Center Presentations

No abstract provided.


A Neuroscientific Approach For Investigating Mental Fatigue Biomarkers In Simulated Driving Trials, Andrea Giorgi, Manuel Picardi, Vincenzo Ronca, Simone Sportiello, Marco Petrelli, Carlo Polidori, Marteyn Van Gasteren, Arnab Barua, Mobyen Uddin Ahmed, Fabio Babiloni, Gianluca Di Flumeri Jan 2024

A Neuroscientific Approach For Investigating Mental Fatigue Biomarkers In Simulated Driving Trials, Andrea Giorgi, Manuel Picardi, Vincenzo Ronca, Simone Sportiello, Marco Petrelli, Carlo Polidori, Marteyn Van Gasteren, Arnab Barua, Mobyen Uddin Ahmed, Fabio Babiloni, Gianluca Di Flumeri

Kentucky Transportation Center Presentations

No abstract provided.


Can Temporary Signs Remind Who Should Yield At Uncontrolled Intersections? – A Driving Simulator Study, Kirti Mahajan, Saumik Sakib Bin Masud, Grace Savoie, Alexandra Kondyli Jan 2024

Can Temporary Signs Remind Who Should Yield At Uncontrolled Intersections? – A Driving Simulator Study, Kirti Mahajan, Saumik Sakib Bin Masud, Grace Savoie, Alexandra Kondyli

Kentucky Transportation Center Presentations

Background: A generic right of way (ROW) rule at uncontrolled intersections is to yield to the vehicle from the right, if not stated otherwise in the right-hand side driving countries such as the US. However, this rule is greatly neglected in practice, resulting in unsafe situations. This study investigated the effectiveness of using two proposed temporary yield signs: “Yield to Traffic on right” (Sign1_YT) and “Yield to Person on right” (Sign2_YP), to remind the drivers of ROW rule at uncontrolled intersections. Method: A driving simulator experiment was conducted with 20 drivers (aged 18-65 years), 50% males, recording observations for 198 …


Exploring The Enablers And Barriers Of Stakeholder's Collaboration Of Maas Platform: A Case Study Of Bangkok, Sirawit Chinvanichai Jan 2024

Exploring The Enablers And Barriers Of Stakeholder's Collaboration Of Maas Platform: A Case Study Of Bangkok, Sirawit Chinvanichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigates the implementation of Mobility as a Service (MaaS) to address fragmented transport services in Bangkok, focusing on identifying enablers, barriers, and concerns for MaaS adoption while quantifying evaluation criteria to determine the most suitable MaaS model. A mixed-methods approach was employed, beginning with a literature review to identify initial enablers and barriers, which were refined through expert meetings. Semi-structured interviews with 14 experts provided deeper insights into Bangkok’s transport context and potential MaaS models, while an AHP survey involving 12 experts quantified and prioritized the evaluation criteria. The findings highlight the roles and responsibilities of MaaS application …


การวิเคราะห์หาเวลาหยุดที่เหมาะสมของหุ้นกู้แปลงสภาพได้ในโครงสร้างพื้นฐานร่วมลงทุนระหว่างรัฐและเอกชน โดยใช้คอปูลา, สหัสวรรษ พาคำ Jan 2024

การวิเคราะห์หาเวลาหยุดที่เหมาะสมของหุ้นกู้แปลงสภาพได้ในโครงสร้างพื้นฐานร่วมลงทุนระหว่างรัฐและเอกชน โดยใช้คอปูลา, สหัสวรรษ พาคำ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในอนาคตประเทศไทยจะมีโครงการร่วมลงทุนระหว่างรัฐและเอกชน (Public Private Partnership หรือ PPP) เกิดขึ้นในต่างจังหวัดเพิ่มมากขึ้น ทำให้นำมาซึ่งความเสี่ยงหลายด้าน เช่น ความเสี่ยงด้านจำนวนผู้ใช้บริการ ความเสี่ยงด้านรายได้จากการจัดเก็บค่าธรรมเนียม และความเสี่ยงด้านเงินกู้ เป็นต้น ส่งผลให้ภาคเอกชนขาดความมั่นใจเข้าร่วมลงทุนในโครงการ PPP ในต่างจังหวัด เพื่อแก้ปัญหาดังกล่าวภาครัฐต้องให้การสนับสนุนทางการเงินในโครงการ PPP ดังนั้น งานวิจัยนี้จึงมีจุดประสงค์เพื่อศึกษาการใช้เงินทุนชั้นลอยด้วยการใช้หุ้นกู้แปลงสภาพ (Convertible debenture) เป็นหุ้นกู้ที่ให้สิทธิหน่วยงานรัฐเป็นผู้ถือหุ้นในโครงสร้างเงินทุน ซึ่งเป็นรูปแบบการสนับสนุนทางการเงินใหม่ในโครงการ PPP และศึกษาสัดส่วนโครงสร้างเงินทุนที่เหมาะสม โดยเสนอการพัฒนาตัวแบบทางคณิตศาสตร์เพื่อวิเคราะห์หาเวลาหยุดที่เหมาะสมสำหรับการแปลงหนี้ให้เป็นทุน ทั้งการวิเคราะห์แบบ Deterministic และ Stochastic ภายใต้สถานการณ์ความไม่แน่นอนของตัวแปรเสี่ยงหลายตัว โดยใช้คอปูลา (Copula) วิเคราะห์ตัวแปรเสี่ยงที่มีความสัมพันธ์กัน ซึ่งจะช่วยเป็นการกำหนดตัวแปรสำคัญในตัวแบบทางคณิตศาสตร์ และนำตัวแบบทางคณิตศาสตร์ไปประยุกต์ใช้กับโครงการตัวอย่างจริง คือ โครงการทางพิเศษสายเมืองใหม่-เกาะแก้ว-กะทู้ จังหวัดภูเก็ต โดยเสนอเป็นทางเลือกให้กับหน่วยงานรัฐนำหุ้นกู้แปลงสภาพไปประยุกต์ใช้กับโครงการ PPP เพื่อวิเคราะห์เปรียบเทียบรูปแบบการสนับสนุนและโครงสร้างเงินทุนที่เหมาะสมสามกรณี ผลลัพธ์ที่ได้ คือ กรณีที่สามหน่วยงานรัฐให้การสนับสนุนเงินทุนชั้นลอยด้วยรูปแบบหุ้นกู้แปลงสภาพและให้เงินสนับสนุนทางตรงในโครงการ PPP ทำให้มีความคุ้มค่าทางการเงินของโครงการสูงสุด และสามารถวิเคราะห์หาเวลาหยุดที่เหมาะสมที่เกิดขึ้นในระยะเวลาดำเนินการของระยะสัมปทานโครงการได้


Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study, Haibin Zhang, Xinzhe Yuan, Genda Chen, Pedro Lomonaco Jan 2024

Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study, Haibin Zhang, Xinzhe Yuan, Genda Chen, Pedro Lomonaco

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Bridges have recently been exposed to an increasing number of natural hazards such as earthquakes and tsunamis. These extreme events have resulted in transverse offsets, overturning moments, and even dropping-off of superstructures due to their weak connection to substructures. These outcomes are potentially prevented or mitigated by developing and deploying sliding, modular, adaptive, replaceable, and two-dimensional (SMART) shear keys as fuse elements between superstructures and substructures. The novelty of SMART shear keys is to enable an adaptive control of both the force and displacement of bridges under different types of loads. In this study, the performance of SMART shear keys …