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Full-Text Articles in Engineering

Treating Contaminated Water: Predicting Reactivities Of Aqueous Organic Contaminants With Hydrated Electrons, And Development Of A Biogarden To Manage Greywater Discharge In Monteverde, Costa Rica, Rose C. Daily Jan 2023

Treating Contaminated Water: Predicting Reactivities Of Aqueous Organic Contaminants With Hydrated Electrons, And Development Of A Biogarden To Manage Greywater Discharge In Monteverde, Costa Rica, Rose C. Daily

Dissertations, Master's Theses and Master's Reports

Advanced reduction processes (ARPs) that generate highly reactive solvated electrons (e-aq) are a promising method for the destruction of conventional and emerging aqueous organic contaminants. While there is a large database of contaminant reactivity with e-aq in the literature, there is little information on the detailed elementary mechanisms for reduction of multifunctional group compounds and the impact of those functional groups on reactivity. As it is difficult to determine specific mechanisms through experiments and time consuming to measure reactivity, the development of computational approaches to elucidate mechanisms and predict reactivity is becoming increasingly important. In …


Development And Testing Of A Low Mass Vibratory Lunar Compactor, Charles Carey Jan 2023

Development And Testing Of A Low Mass Vibratory Lunar Compactor, Charles Carey

Dissertations, Master's Theses and Master's Reports

NASA and other agencies are working to return to the moon, with the Artemis Program [1]. As a part of this new effort, an emphasis is being placed on having a sustained presence, building lunar bases and other permanent structures. The development of such infrastructure will require the development of civil engineering structures, and site preparation becomes a necessity. The Planetary Surface Technology Development Laboratory is developing a low mass lunar compactor as part of an autonomous site preparation vehicle in partnership with Colorado School of Mines, funded by NASA’s 2021 Lunar Surface Technology Research grant. The low mass lunar …


Performance Evaluation Of Using Waste Glass Powder And Fly Ash In Alkali-Activated Slag Binder And Mortar Samples As Partial Precursors, Sunday A. Eniola Jan 2023

Performance Evaluation Of Using Waste Glass Powder And Fly Ash In Alkali-Activated Slag Binder And Mortar Samples As Partial Precursors, Sunday A. Eniola

Dissertations, Master's Theses and Master's Reports

The increasing environmental burden at landfills due to the disposal of waste glass has motivated the scientific community to find an alternative for its utilization. One of these promising routes is to use glass powder (GP) as precursor and waste glass sands as sand replacement in alkali-activated slag (AAS) mortar to reduce the setting time, shrinkage, and efflorescence characteristics for the field applications by comparing with class F fly ash (FFA). This study first experimentally investigates the setting behavior, shrinkage behavior and compressive strength, and efflorescence characteristics of AAS binder prepared with partially replaced glass powder and fly ash. The …


Predicting The Reactivities And Reaction Mechanisms Of Photochemically Produced Reactive Intermediates, Benjamin Barrios Cerda Jan 2023

Predicting The Reactivities And Reaction Mechanisms Of Photochemically Produced Reactive Intermediates, Benjamin Barrios Cerda

Dissertations, Master's Theses and Master's Reports

Photochemically produced reactive intermediates (PPRIs) such as the hydroxyl radical, carbonate radical (CO3•-) singlet oxygen (1O2) and triplet state of chromophoric dissolved organic matter (3CDOM*) are formed in sunlit natural waters upon photoexcitation of chromophoric dissolved organic matter (CDOM). PPRIs react with the organic compounds involved in key environmental processes, resulting in transformation products of smaller molecular weight than their parent compounds. Photochemical transformation of these key water constituents due to their reactions with PPRIs may pose potential effects on human and aquatic ecosystems. Consequently, there is a need …


Bioaccumulation Of Polychlorinated Biphenyl Compounds And Mercury In A Mining Impacted Aquatic Ecosystem, Michelle Bollini Jan 2023

Bioaccumulation Of Polychlorinated Biphenyl Compounds And Mercury In A Mining Impacted Aquatic Ecosystem, Michelle Bollini

Dissertations, Master's Theses and Master's Reports

The Keweenaw area continues to be influenced by the century of copper mining that ended nearly 50 years ago. This project is focused on Torch Lake, an aquatic ecosystem that has been heavily impacted by mining waste disposal. The watershed has been impaired by mine discharge and tailings, smelter and smokestack plumes, and poor waste disposal practices. The lake is listed as a Great Lakes Area of Concern with beneficial use impairments of restrictions on fish consumption and a degraded benthic community. Polychlorinated biphenyl compounds (PCBs) and methylmercury (MeHg) are persistent, bioaccumulative, and toxic substances (PBTs). These contaminants pose threats …


Quantifying The Impact Of Wide Base Tires On Pavement Performance In Michigan, Lei Yin Jan 2023

Quantifying The Impact Of Wide Base Tires On Pavement Performance In Michigan, Lei Yin

Dissertations, Master's Theses and Master's Reports

This study aimed to investigate the use of wide base tires (WBT) in Michigan to quantify the effect of different percentages of WBT loads on flexible and rigid pavements. Surveys and field investigations were conducted to quantify the WBT usage in Michigan. The JULEA (for flexible pavements) and Illislab (for JPCP) software programs were used to calculate the mechanical response between dual tire (DT) and WBT loads, while the Mechanical-Empirical (ME) pavement design process was utilized for damage accumulation and pavement distress analysis. Investigation results rationalized the assumption of WBT proportion for design purposes as 10% currently and up to …


The Rhetorical Art Of Risk Assessment: Lessons From Risk Management In Rural And Tribal Communities, John L. Velat Jan 2023

The Rhetorical Art Of Risk Assessment: Lessons From Risk Management In Rural And Tribal Communities, John L. Velat

Dissertations, Master's Theses and Master's Reports

Risk assessment, mitigation, and communication rely on data from multiple sources to form a complete understanding of hazards and how to manage them. Experts can use these data to make informed decisions about the nature and extent of risks and inform the public to protect health, the environment, and economic welfare. However, in an effort to objectively make decisions, technical experts and policymakers increasingly rely on quantitative data as the most important determiner of risk, which can alienate the public, limit risk understanding, and delay or miss obvious signals of impending catastrophe. I examine several cases based on my experiences …


Eutrophication On Twin Lakes: Applying A Phosphorus Budget And Shoreline Surveys To Assess Current & Historical Lake Health, Tyler K. Lemahieu Jan 2023

Eutrophication On Twin Lakes: Applying A Phosphorus Budget And Shoreline Surveys To Assess Current & Historical Lake Health, Tyler K. Lemahieu

Dissertations, Master's Theses and Master's Reports

The Twin Lakes system, a series of lakes including Lake Gerald and Lake Roland, was historically categorized as oligotrophic but is now mesotrophic having experienced cultural eutrophication. A mass balance phosphorus budget model was constructed for the Twin Lakes system in Houghton, Co. Michigan for the 2022 stratified season. Additional spatial insights were gleaned through a survey of shoreline water quality, which corroborated the model results. The lakes currently experience substantial depletion of hypolimnetic dissolved oxygen during late summer stratification. A budget reveals approximately 22% (6.6 kg) of the current 29.5 kg total phosphorus inputs to Twin Lakes (during the …


Robotic Inspection And Data Analytics To Localize And Visualize The Structural Defects Of Civil Infrastructure, Jinglun Feng Jan 2023

Robotic Inspection And Data Analytics To Localize And Visualize The Structural Defects Of Civil Infrastructure, Jinglun Feng

Dissertations and Theses

Ground Penetrating Radar (GPR) serves as a significant nondestructive evaluation (NDE) technique to inspect and survey underground objects (e.g., rebars, utility pipes) in complex urban environments. In addition to GPR, visual-based surface defect detection plays a crucial role in assessing and maintaining civil infrastructure. To facilitate deployment on a robotic platform and enhance inspection capabilities, the integration of GPR and visual-based sensors, such as RGB-D cameras, is crucial to obtain accurate subsurface and surface information. This thesis presents a novel robotic-based inspection system for the efficient collection of NDE data and accurate 3D reconstruction of both subsurface and surface infrastructure …


Elevation-Distributed Multistage Reverse Osmosis Desalination With Seawater Pumped Storage, Hani E. Elsayed-Ali Jan 2023

Elevation-Distributed Multistage Reverse Osmosis Desalination With Seawater Pumped Storage, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

A seawater reverse osmosis (RO) plant layout based on multistage RO with stages located at different elevations above sea level is described. The plant uses the weight of a seawater column from pumped storage as head pressure for RO (gravity-driven multistage RO) or to supplement high-pressure pumps used in RO (gravity-assisted multistage RO). The use of gravitational force reduces the specific energy for RO compared to using high-pressure pumps. By locating the RO stages at different elevations based on demand sites, the total specific energy consumption for RO and permeate transport to different elevations above sea level is reduced from …


Understanding And Assessing Demographic (In)Equity Resulting From Extreme Heat Exposure Due To Lack Of Tree Canopies In Norfolk, Va Using Agent-Based Modeling, Virginia Zamponi, Kevin O'Brien, Erik Jensen, Brandon Feldhaus, Russell Moore, Christopher J. Lynch, Ross Gore Jan 2023

Understanding And Assessing Demographic (In)Equity Resulting From Extreme Heat Exposure Due To Lack Of Tree Canopies In Norfolk, Va Using Agent-Based Modeling, Virginia Zamponi, Kevin O'Brien, Erik Jensen, Brandon Feldhaus, Russell Moore, Christopher J. Lynch, Ross Gore

VMASC Publications

Prolonged exposure to extreme heat can result in illness and death. In urban areas of dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat, extreme heat conditions can arise regularly and create harmful environmental exposures for residents daily during certain parts of the year. Tree canopies provide shade and help to cool the environment, making mature trees with large canopies a simple and effective way to reduce urban heat. We develop a demographically representative 1 (agent): 1 (person) agent-based model to understand the extent to which different demographics of residents in Norfolk, VA are equitably shaded …


Efficient Maritime Object Detection And Validation For Enhancing Safety Of Uncrewed Marine Systems, Ahmed Saglam, Yiannis Papelis Jan 2023

Efficient Maritime Object Detection And Validation For Enhancing Safety Of Uncrewed Marine Systems, Ahmed Saglam, Yiannis Papelis

VMASC Publications

Safe operation of uncrewed maritime systems is a major concern in the presence of other vehicles or obstacles. Typically, perception algorithms utilize sensor data to identify obstacles that must be avoided, and AI algorithms are used to interpret raw sensor data for use in navigation and object avoidance algorithms. However, perception algorithms are typically computationally expensive. In this paper, we present an efficient method for detecting obstacles using raw lidar data in the form of range or Point Cloud, employing computationally efficient techniques that do not depend on trained models or AI matching. The approach
converts the sensor readings into …


Characterizing Variability In The Transient Storage Zones Of Miller Run In Lewisburg, Pa, Sabrina Savidge Jan 2023

Characterizing Variability In The Transient Storage Zones Of Miller Run In Lewisburg, Pa, Sabrina Savidge

Master’s Theses

The transient storage zone processes are investigated in a small second order stream with a 2.2 square kilometer watershed. The presence of transient storage zones in small streams impacts the available flow paths for water and results in a wider range of residence times for water and dissolved chemicals than would be predicted by considering only the main channel flow path. Residence times can be used to quantify the health of a stream as several biogeochemical and ecological processes occur in water slowed by transient storage.

Sections of the studied stream are impacted by varying types of stream restoration practices …


Strengthening Of Damaged Structural Members With External Frp, Krishna Tulasi Gadde Jan 2023

Strengthening Of Damaged Structural Members With External Frp, Krishna Tulasi Gadde

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fiber reinforced polymer (FRP) composites are excellent alternatives to traditional materials for civil infrastructure. Several researchers have worked on the application of FRP composites for construction, repair, and rehabilitation of structures. This research aims at evaluating the use of carbon, glass, basalt, and hybrid FRPs with epoxy and polyurethane resin systems for rehabilitation of damaged structural components. Following evaluations were carried out in this research: (i) tension testing of FRP coupons, (ii) compression testing of concrete cylinders with and without damaged sections/FRP reinforcements, (iii) flexural testing of external-FRP reinforced RC beams with and without damages, (iv) pull-off tests on FRP …


Exploring The Usage Of Acid Mine Drainage Sludge As A Soil Amendment For Reclaimed Mine Lands, Brady Watters Jan 2023

Exploring The Usage Of Acid Mine Drainage Sludge As A Soil Amendment For Reclaimed Mine Lands, Brady Watters

Graduate Theses, Dissertations, and Problem Reports (ETD)

Acid mine drainage (AMD) is a form of water pollution generated when water and oxygen come into contact with sulfide minerals, forming metal ions, sulfuric acid, and sulphates in solution. AMD is characterized by its toxic metals content and low pH, both of which are an environmental concern. The treatment of AMD separates the contaminants into a high-water content sludge. This sludge is a pure waste product under current evaluation for alternative uses as well as improvements to storage and treatment processes. This thesis focused on analyzing the potential for AMD sludge to be used in recently reclaimed lands as …


Frp Pedestrian Bridges, Joseph Ryan Virga Jan 2023

Frp Pedestrian Bridges, Joseph Ryan Virga

Graduate Theses, Dissertations, and Problem Reports (ETD)

Advanced fiber-reinforced polymer (FRP) composites are being used as mainstream structural materials to build complex infrastructure systems. Such application of FRP composites can be attributed to their high strength-to-weight and stiffness-to-weight ratios, corrosion resistance, higher energy absorption, durability, and competitive life-cycle costs. FRP composites are increasingly being considered as suitable alternative structural materials to traditional construction materials such as timber, concrete, and steel.

In this work, detailed experimental investigation has been carried out on different types of glass FRP composite pedestrian bridges with FRP and/or timber deck. Four full-scale FRP pedestrian bridges, including 70`×8.5’ and 70’×10’ single-span bridges, a 16’×8’ …


Spatiotemporal Trends In Particle-Associated Microbial Communities In A Chlorinated Drinking Water Distribution System, Madison Haddix Jan 2023

Spatiotemporal Trends In Particle-Associated Microbial Communities In A Chlorinated Drinking Water Distribution System, Madison Haddix

Graduate Theses, Dissertations, and Problem Reports (ETD)

Bacteria can survive treatment and enter drinking water distribution systems (DWDSs), or enter DWDSs through intrusion or maintenance work on the system. DWDSs can also be suitable environments for bacterial regrowth. Many factors can affect the microbial community composition of DWDSs, including various spatiotemporal, hydraulic, and water quality parameters. Although most bacteria within DWDSs are harmless, opportunistic pathogens, such as Legionella pneumophila, Pseudomonas aeruginosa, and Mycobacterium avium, can inhabit DWDSs and premise plumbing and are the leading cause of waterborne disease outbreaks in developed countries. Previous studies have attempted to establish relationships between various parameters and microbial …


Feasibility Of Applying Motion Magnification In Subsurface Defect Detection For Concrete And Fiber-Reinforced Polymer Specimens, Nagavardhani Malineni Jan 2023

Feasibility Of Applying Motion Magnification In Subsurface Defect Detection For Concrete And Fiber-Reinforced Polymer Specimens, Nagavardhani Malineni

Graduate Theses, Dissertations, and Problem Reports (ETD)

Irrespective of size and complexity, every civil infrastructure needs certain scrutiny regarding its structural health to ensure its serviceability during its lifetime. In olden times such scrutiny was done with the aid of destructive testing methods using sensors that required cumbersome and expensive installations and led to the destruction of at least part of the tested specimen. However, in recent times, many non-destructive methods, such as acoustic emission testing, electromagnetic testing, and laser testing methods have emerged, leaving the specified tested specimen undisturbed. With the advancement in sensor technology like motion magnification and with the help of access to high-speed …


Development Of A Framework To Support Community-Scale Nutrient Recovery For Local Crop Fertilization And Production, Scott A. Lopez Jan 2023

Development Of A Framework To Support Community-Scale Nutrient Recovery For Local Crop Fertilization And Production, Scott A. Lopez

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nutrient and resource recovery (NRR) has become increasingly crucial as regions face deteriorating sanitation infrastructures, limited support, and growing environmental challenges. Implementing region-specific NRR technologies and systems could provide effective circular economy insights into addressing these challenges. Because of the multidisciplinary challenges associated with the design and implementation of NRR strategies, various government and local decision-makers need to collaborate effectively in the decision-making process. Structured decision-making (SDM) methodologies are practical when determining the most appropriate NRR strategy for nutrient-rich waste streams. However, applications of computational SDM limited because of the vast amounts of data that are needed to analyze the …


Using Modflow To Assess Groundwater Storage Enhancement Via A Floodplain Infiltration Basin, Lindsay Henning Jan 2023

Using Modflow To Assess Groundwater Storage Enhancement Via A Floodplain Infiltration Basin, Lindsay Henning

All Master's Theses

Delaying groundwater discharge into rivers until it is critically needed during baseflow conditions provides promise for lowering elevated stream temperatures and improving habitat for aquatic species. Increasing groundwater storage may accomplish this in locations where excess spring runoff can be captured and allowed to infiltrate into the subsurface for later beneficial use, a process known as Managed Aquifer Recharge (MAR). Here, MAR via an infiltration basin is considered at a site along the Teanaway River in central Washington State. The effects of simulated ephemeral ponds of sizes varying from 554 m3 to 2430 m3 (0.449 acre-feet to 1.97 …


Implementation Of Ground Penetrating Radar (Gpr) And Complementary Non-Destructive Testing On Concrete Structures, Macy Spears Jan 2023

Implementation Of Ground Penetrating Radar (Gpr) And Complementary Non-Destructive Testing On Concrete Structures, Macy Spears

College of Graduate Studies: Theses & Dissertations

This study analyzes the application and practicality of different non-destructive testing (NDT) methods for the inspection of reinforced concrete. There are two studies discussed in this paper. The first one is a laboratory investigation, utilizing ground penetrating radar (GPR) on concrete slabs that consisted of simulated defects to mimic those found in real concrete structures. This served as a preliminary experiment to verify the GPR data with the design of the slabs. The following study describes a field investigation on an old bridge deck, which involved multiple testing methods. The techniques used were GPR, impact echo (IE), ultrasonic pulse echo …


A Theoretical And Computational Model For Aquaponics Systems, Isabella M. Digiulio Jan 2023

A Theoretical And Computational Model For Aquaponics Systems, Isabella M. Digiulio

Honors Theses

Aquaponics, a sustainable farming technique combining the principles of aquaculture and hydroponics, suffers from uncertainty in its optimal operating conditions, preventing large-scale adoption of this technology. Relying on experimentation or full-scale testing to address these uncertainties is an approach that is material, labor, time, and cost intensive. As a result, aquaponics would benefit from a complete computational model of the system. This would allow for information to be gained without long and expensive experiments, but rather with knowledge of system operations and a modeling software package. In this study, the Activated Sludge Model 1 (ASM1) matrix framework, traditionally used in …


An Investigation Into Aluminum’S Torsional Behavior Of Circular, Rectangular, And Square Cross-Sections, Marly Mcclintock Jan 2023

An Investigation Into Aluminum’S Torsional Behavior Of Circular, Rectangular, And Square Cross-Sections, Marly Mcclintock

Honors Theses

The Specifications for Aluminum Structures (2020) provides the standards that structural engineers follow for aluminum design. Included in these specifications are limit state equations that use strength properties to calculate a member’s initial yield, full yield, and rupture values. One limit state that the standards currently neglect is the torsional failure of solid bars. Torsion is the act of rotation caused by a twisting force, otherwise known as torque. Future installments of the specifications hope to include torsional yielding and rupture equations, so this study investigates the validity of these proposed equations.

Two different aluminum alloys were investigated for this …


Occurrence Of Per- And Polyfluoroalkyl Substances (Pfas) In New Hampshire Biosolids, Katherine A. Wieck Jan 2023

Occurrence Of Per- And Polyfluoroalkyl Substances (Pfas) In New Hampshire Biosolids, Katherine A. Wieck

Honors Theses and Capstones

Per- and polyfluoroalkyl substances (PFAS) are a group of over 4,000 compounds used in the manufacturing of products including aqueous film forming foams for firefighting, stain repellents, waterproofing agents, and nonstick cookware since their initial development in the 1940s. The long fluorinated carbon chain structure of PFAS causes chemical and thermal stability, and thus resistance to biodegradation. Biosolids produced at wastewater facilities for uses such as agricultural land-applied compost and fertilizer for lawns and athletic fields, as well as sludge disposed in landfills can cause contamination of groundwater and surface water. This poses a significant threat to human and environmental …


Time-Specific Safety Performance Functions For Different Advanced Traffic Management Strategies, Jingwan Fu Jan 2023

Time-Specific Safety Performance Functions For Different Advanced Traffic Management Strategies, Jingwan Fu

Electronic Theses and Dissertations, 2020-2023

Time-specific Safety Performance Functions (SPFs) were proposed to achieve accurate and dynamic crash frequency predictions and bridge the gap between annual crash frequency prediction and real-time crash likelihood prediction. This research proposed time-specific SPFs considering the temporal variation in crashes and traffic characteristics. Firstly, the developed time-specific SPFs that include different ATM strategies (i.e., HOV, merge, diverge and reversible lanes segments) were investigated in this study. The results indicate that the traffic turbulence during specific hours would relate to crash occurrence. Further, the variables that represent the speed and occupancy differences between the HOV lanes/reversible lanes and general-purpose lanes were …


Joint Probability Analysis Of Extreme Precipitation And Water Level For Chicago, Illinois, Anna Li Holey Jan 2023

Joint Probability Analysis Of Extreme Precipitation And Water Level For Chicago, Illinois, Anna Li Holey

Dissertations, Master's Theses and Master's Reports

A compound flooding event occurs when there is a combination of two or more extreme factors that happen simultaneously or in quick succession and can lead to flooding. In the Great Lakes region, it is common for a compound flooding event to occur with a high lake water level and heavy rainfall. With the potential of increasing water levels and an increase in precipitation under climate change, the Great Lakes coastal regions could be at risk for more frequent and severe flooding. The City of Chicago which is located on Lake Michigan has a high population and dense infrastructure and …


Study Of Eco-Driving And Charging Planning In Connected And Automated Vehicles Environment, Pradeep Bhat Jan 2023

Study Of Eco-Driving And Charging Planning In Connected And Automated Vehicles Environment, Pradeep Bhat

Dissertations, Master's Theses and Master's Reports

In this dissertation, the development of eco-driving and charging planning algorithms in the connected and automated vehicle environment (CAV) are presented. CAV technologies provide opportunities for potential energy savings and efficiency improvement of transportation networks, which are explored through multiple research tasks in this study.

The objective of the first study presented in Chapter 2 is to reduce vehicle dynamic losses and required tractive force while completing trip distance within a given travel time. Sequential Quadratic Programming method is employed for this nonlinearly constrained optimization problem. The validation result illustrates the benefits of optimal velocity trajectories. The objective of the …


การกำจัดสารอินทรีย์และไนโตรเจนควบคู่กับการผลิตโพลีไฮดรอกซีแอลคาโนเอตด้วยจุลินทรีย์เชื้อผสมร่วมกับการเติม Thauera Mechernichensis Tl1, นวภัทร ช่อทอง Jan 2023

การกำจัดสารอินทรีย์และไนโตรเจนควบคู่กับการผลิตโพลีไฮดรอกซีแอลคาโนเอตด้วยจุลินทรีย์เชื้อผสมร่วมกับการเติม Thauera Mechernichensis Tl1, นวภัทร ช่อทอง

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาการผลิตพลาสติกชีวภาพชนิดโพลีไฮดรอกซีแอลคาโนเอต (พีเอชเอ) ควบคู่กับการกำจัดสารอินทรีย์และไนโตรเจน ด้วยจุลินทรีย์สายพันธุ์ผสมร่วมกับการเติม Thauera mechernichensis TL1 ในอัตราส่วน 97.5 : 2.5 % g MLVSS ภายใต้สภาวะที่มีอาหารเกินพอสลับกับขาดแคลน (feast and famine conditions) ภายในถังปฏิกรณ์แบบกึ่งเท (sequencing batch reactor) จำนวน 2 ถัง โดยในถังปฏิกรณ์ที่ 1 มีการเติมอากาศตลอดเวลาทั้งช่วงที่มีอาหารเกินพอ และช่วงที่ขาดแคลนอาหาร (aerobic feast/famine) และในถังปฏิกรณ์ที่ 2 มีการเติมอากาศเฉพาะช่วงอาหารเกินพอ และปล่อยให้เกิดสภาวะแอน็อกซิกในช่วงขาดแคลนอาหาร (aerobic feast/anoxic famine) กำหนดค่าอายุสลัดจ์ (SRT) 10 วัน และรอบการเดินระบบ (cycle time) ระยะเวลา 2 วัน โดยใช้อะซิเตท 1,000 mgCOD/L เป็นแหล่งคาร์บอน โดยมีความเข้มข้นแอมโมเนียเริ่มต้น 70 mgN/L และศึกษาความสามารถในการสะสมพีเอชเอสูงสุดของตะกอนจุลินทรีย์ในระบบทีละเทแบบเติมแหล่งคาร์บอนต่อเนื่อง (fed-batch reactor) ผลการศึกษาพบว่า ถังปฎิกรณ์ที่ 1 ผลิต พีเอชเอได้สูงสุดที่ในรอบการเดินระบบที่ 28 โดยมีปริมาณ 10.04 % ของน้ำหนักเซลล์แห้ง และมีประสิทธิภาพในการกำจัดสารอินทรีย์ 88.1 ± 1.3% แต่ไม่มีประสิทธิภาพในการกำจัดไนโตรเจน ส่วนถังปฎิกรณ์ที่ 2 ผลิตพีเอชเอได้สูงสุดที่ในรอบการเดินระบบที่ 35 โดยมีปริมาณ 8.37 % ของน้ำหนักเซลล์แห้ง มีประสิทธิภาพในการกำจัดสารอินทรีย์ 87.6 ± 1.7% และมีประสิทธิภาพในการกำจัดไนโตรเจน 78.0 ± 2.0% และได้ศึกษากลุ่มประชากรจุลินทรีย์ในระบบด้วยเทคนิค 16S rRNA gene amplicon sequencing (MiSeq) พบว่า จุลินทรีย์กลุ่ม Thauera …


Labile Carbon And Soil Texture Control Nitrogen Transformation In Deep Vadose Zone, Lidong Li, Jordan Shields, Daniel D. Snow, Michael Kaiser, Arindam Malakar Jan 2023

Labile Carbon And Soil Texture Control Nitrogen Transformation In Deep Vadose Zone, Lidong Li, Jordan Shields, Daniel D. Snow, Michael Kaiser, Arindam Malakar

Daugherty Water for Food Global Institute: Faculty Publications

Understanding transient nitrogen (N) storage and transformation in the deep vadose zone is critical for controlling groundwater contamination by nitrate. The occurrence of organic and inorganic forms of carbon (C) and nitrogen and their importance in the deep vadose zone is not well characterized due to difficulty in sampling and the limited number of studies. We sampled and characterized these pools beneath 27 croplands with different vadose zone thicknesses (6–45 m). We measured nitrate and ammonium in different depths for the 27 sites to evaluate inorganic N storage. We measured total Kjeldahl nitrogen (TKN), hot-water extractable organic carbon (EOC), soil …


ปัจจัยที่ส่งผลต่อความตั้งใจเชิงพฤติกรรมในการเลือกใช้ยานยนต์รับส่งผู้โดยสารอัตโนมัติ (Autonomous Shuttle Pod) ในจุฬาลงกรณ์มหาวิทยาลัย, ยอดพล เพชราวุธ Jan 2023

ปัจจัยที่ส่งผลต่อความตั้งใจเชิงพฤติกรรมในการเลือกใช้ยานยนต์รับส่งผู้โดยสารอัตโนมัติ (Autonomous Shuttle Pod) ในจุฬาลงกรณ์มหาวิทยาลัย, ยอดพล เพชราวุธ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ยานยนต์รับส่งผู้โดยสารอัตโนมัติ (Autonomous Shuttle Pod) ได้รับการออกแบบมาเพื่อตอบสนองความต้องการขนส่งรูปแบบใหม่ พร้อมทั้งเพิ่มประสิทธิภาพและความปลอดภัยในการเดินทาง อย่างไรก็ตามความสำเร็จของเทคโนโลยีนี้ขึ้นอยู่กับการยอมรับของสาธารณชน การศึกษานี้มุ่งเน้นไปที่การตรวจสอบทัศนคติและปัจจัยที่ส่งผลต่อความตั้งใจเชิงพฤติกรรมในการเลือกใช้ยานยนต์รับส่งผู้โดยสารอัตโนมัติ โดยขยายแบบจำลองทฤษฎีรวมการยอมรับและการใช้เทคโนโลยี 2 (UTAUT2) ที่เพิ่มปัจจัยด้าน การรับรู้ด้านความเสี่ยง, การรับรู้ด้านความไว้วางใจ, ภาพลักษณ์ และการเปรียบเทียบกับรูปแบบการเดินทางอื่น โดยสร้างแบบจำลองสมการเชิงโครงสร้าง (SEM) เพื่อหาความสัมพันธ์ระหว่างปัจจัยและเจตนาเชิงพฤติกรรมภายใต้แบบจำลอง อย่างไรก็ตามการวิจัยนี้ได้วิเคราะห์องค์ประกอบเชิงสำรวจ (EFA) เพื่อค้นหาองค์ประกอบที่แท้จริงภายใต้ตัวบ่งชี้ที่พัฒนาขึ้น แบบสอบถามดำเนินกับกลุ่มตัวอย่างในพื้นที่จุฬาลงกรณ์มหาวิทยาลัยจำนวน 409 คน ผลการศึกษาทัศนคติพบว่า คนชื่นชอบยานยนต์รับส่งผู้โดยสารอัตโนมัติในด้านของการบริการ ได้แก่ การเรียกใช้ได้ทุกที่ทุกเวลาผ่านแอพพลิเคชั่น, บริการนอกเวลาปกติ และการปรับเปลี่ยนเส้นทาง อีกทั้งยังถูกมองว่ามีศักยภาพในการเข้ามาแทนที่รถ Pop Bus และ Muvmi สำหรับการวิเคราะห์แบบจำลองสมการเชิงโครงสร้าง (SEM) พบว่าปัจจัยที่ส่งผลต่อการเลือกใช้ยานยนต์รับส่งผู้โดยสารอัตโนมัติของผู้คน ได้แก่ ความคาดหวังด้านประสิทธิภาพ, ประโยชน์ในการใช้ในชีวิตประจำวัน, การรับรู้ด้านความไว้วางใจ, สิ่งอำนวยความสะดวก, ความพอใจในบริการเหนือราคา, ความไว้วางใจด้านบริการและราคา, การรับรู้ความเสี่ยง และการรับรู้ว่าใช้งานได้ง่าย ในขณะที่ความคาดหวังด้านความพยายาม และ อิทธิพลของสังคม ส่งผลในทางอ้อม