Digital Commons Network^™

Bioremediation Potential Of Indigenous Stutzerimonas Stutzeri 08tbb Isolated From Mercury-Contaminated Gold Mining Sites In Indonesia, Uun Rohmawati, Juanita Hibatullah, Achmad Rodiansyah, Yunita Messe, Dwi Nur Aini Fajriah

Applied Environmental Research

Artisanal and small-scale gold mining (ASGM) widely uses mercury (Hg) in the amalgamation process, and the resulting waste is often discharged directly into the environment, posing serious risks to ecosystems and human health because of the high toxicity of Hg. This study aimed to isolate and screen indigenous Hg-tolerant bacteria from contaminated gold mining sites in Indonesia; characterize the most effective isolate using morphological, biochemical, and molecular approaches; evaluate Hg(II) degradation performance using ICP‒OES, FTIR, and SEM analyses; and identify key metabolites involved in Hg detoxification through untargeted LC–HRMS metabolomics. A total of 51 bacterial isolates were obtained from Hg-contaminated …

Assessment Of Chromosomal Abnormalities In Hybrid Catfish In Reservoir Contaminated With Heavy Metals From Municipal Landfill, Tanadol Savigun, Natchanon Thiratanaboon, Nuttawadee Maneesan, Manop Sriuttha, Lamyai Neeratanaphan

Applied Environmental Research

In this study, the concentrations of heavy metals (As, Cd, Cr and Pb) in water, sediment, and hybrid catfish (Clarias gariepinus x C. macrocephalus) as well as chromosomal abnormalities (CAs) from a reservoir affected by leachate from a municipal landfill were compared to those in an unaffected reservoir. Heavy metal concentrations were analyzed using inductively coupled plasma‒optical emission spectrometry (ICP‒OES). Chromosomes were prepared from kidney cells by direct methods. The As, Cd and Pb concentrations in the water and sediment from both reservoirs were within the Thailand water and soil standards. The concentrations of As and Cd in the water …

Ammonium Adsorption From Aqueous Solutions Using Mnfe2o4-Functionalized Coffee Husk Biochar Nanocomposites : An Evaluation Of Hno3 And Naoh Activation, Thuy-Tien Do, Huu-Tap Van, Thi-Minh-Thu Nguyen

Applied Environmental Research

This research investigated the development of MnFe2O4-based composite adsorbents (MFO@CFA and MFO@CFB) by activating coffee husk-derived biochar with HNO3 and NaOH, followed by synthesis through coprecipitation and hydrothermal techniques. The structural and chemical properties of the nanocomposites were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Batch adsorption experiments were used to assess ammonium removal efficiency across a range of conditions: solution pH (3–8), contact time (5–120 min), adsorbent dosage (0.2–3 g L-1), and initial ammonium concentration (10–60 mg L-1). The findings indicated that compared with MFO@CFB, which was synthesized from NaOH-activated biochar, MFO@ CFA, derived …

Assessing Forest Fragmentation And Edge Expansion In Nan Province, Thailand, Using Landsat Data (2014–2022), Kasidit Rison, Marut Fuangarworn, Chatchawan Chaisuekul

Applied Environmental Research

The increasing pressure from land-use change and agricultural expansion in Nan Province, northern Thailand, has accelerated forest fragmentation and reduced the ecosystem service value (ESV) of the landscape. This study aims to: assess land use and forest fragmentation change in Nan Province between 2014 and 2022, and evaluate the impact of land use change on ESV. Landsat 8 OLI satellite imagery from 2014 and 2022 was used to classify land cover into five types: forest, agriculture, settlements, exposed soil, and others. Forest fragmentation was evaluated using landscape metrics such as patch number, mean patch size, edge length, and core area. …

Application Of Diatom Indices To Monitor Environmental Shifts In The Downstream Tuntang River, Central Java, Mirza Hanif Al Falah, Tri Retnaningsih Soeprobowati, Hadiyanto -, Muhammad Isnaini Ibnu Sabil, Marta Wojewódka-Przybył, Łukasz Kruszewski, Paweł Rydelek

Applied Environmental Research

Diatoms are widely recognized as sensitive bioindicators for reconstructing past water quality and ecological changes in aquatic ecosystems. In this study, multiple diatom-based indices were applied to sediment cores collected from three downstream stations of the Tuntang River, Central Java, to infer long-term environmental change in a tropical river system. A total of 38 sediment subsamples were analyzed, with dominant taxa including Fragilaria crotonensis (2.4–18.6%), Nitzschia palea (3.1–22.4%), and Aulacoseira granulata (2.0–15.8%), indicating sustained nutrient enrichment. Diatom indices consistently classified conditions as mesotrophic to eutrophic throughout the sediment profiles. The occurrence of the marine diatom Cylindrotheca closterium (up to 6.3%) …

Environmental Sustainability Performance And Efficiency In Thailand’S Rajabhat Universities : A Cross-Regional Analysis Of The Impact Rankings, Konstantinos Balis

Applied Environmental Research

Higher education institutions (HEIs) are expected to increasingly communicate their contributions to the United Nations’ Sustainable Development Goals (SDGs), with the rise of alternative sustainability rankings serving as prominent reporting instruments for institutional transparency. In Thailand, Rajabhat Universities, a network of government HEIs historically associated with their mission of teacher training and local development, have been actively participating in the Times Higher Education (THE) Impact Rankings, presenting a unique case study to explore cross-regional sustainability efforts in relation to global benchmarks. To evaluate trends, regional disparities, and engagement performance across the sustainability pillars, this study uses a descriptive quantitative design …

Initial Screening Of Halophilic Plastic-Degrading Bacteria From Mangrove Water And Sediment In Pekalongan, Indonesia, Novia Safinatunnajah, Muhammad Zainuri, Aris Ismanto, Tony Hadibarata, Kunarso -, Sugeng Widada, Hermin Pancasakti Kusumaningrum, Candra Wahyuningsih

Applied Environmental Research

Microplastic pollution in tropical mangrove ecosystems represents an increasing environmental concern, particularly in coastal regions such as Pekalongan, Indonesia, where industrial and residential activities contribute substantially to plastic waste. This study aimed to isolate and preliminarily screen halophilic bacteria from mangrove sediments and seawater collected from a plastic-impacted coastal area. Using mineral salt medium (MSM) supplemented with polyethylene glycol (PEG), six bacterial strains were obtained and evaluated for their potential to interact with polyethylene (PE) and polypropylene (PP) on the basis of gravimetric weight loss measurements. Among the isolates, Halomonas Cupida A1, Marinobacter nauticus A6.3, and Marinobacter nauticus SD5.2 exhibited …

Recycling Waste Polyethylene Terephthalate For Asphalt Modification: A Comprehensive Review On Material Properties, Processing Techniques, And Engineering Applications, Ruizhe Huang, Feng Ma, Ke Shi, Zhen Fu, Jenny Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Polyethylene terephthalate (PET) is a thermoplastic polyester widely used in beverage bottles and packaging materials, accounting for approximately 60% of global plastic production. Due to its non-biodegradable nature, the accumulation of waste PET has posed a serious environmental challenge worldwide. In recent years, the recycling of PET for use in road engineering has been considered an effective approach to promote resource circulation and reduce plastic pollution. This paper first reviews the main recycling methods of PET, including mechanical shredding and chemical depolymerization, and analyzes its molecular structure, thermal properties, and reprocessing adaptability. Two typical engineering application paths are then evaluated: …

Proposed Design Approach Of Bolted Cruciform Stiffened End-Plate Connections And Bolted Circular Flange Plate Connections Under Combined Loading For Enhanced Economy And Performance, Cesar E. Aguirre

Civil Engineering Dissertations

This research will deliver a substantive contribution to the advancement of design practice for bolted circular flange connections and cruciform stiffened end-plate connections — critically evaluating existing approaches, identifying their limitations, and proposing evidence-based design frameworks that enhance structural performance, predictability, and safety across relevant engineering applications.In addition provide economical benefits.

Construction Industry Preparedness For Generation Z And Millennials: Aligning Industry Characteristics With Workforce Job Preferences, Ameenullah Amiri, Dhaval R. Gajjar, Jason D. Lucas

The Professional Constructor

The construction industry in the United States suffers from workforce shortages, partly due to younger generations being hired more slowly than baby boomers retire. Generation Z’s (Gen Z) lack of interest in joining the construction industry, coupled with the retirement of older workers, has amplified the problem. This paper investigates existing literature to identify the work and career preferences of Gen Z and Millennials and determine where the industry may focus efforts to attract these two generations. Through a systematic literature review, this study identified overlaps and gaps between the current construction industry workforce’s perceptions of the industry and the …

Anonymized Survey Dataset On Road Safety Assessment During Construction Of Bus Rapid Transit (Brt) Corridors In Dar Es Salaam, Tanzania, Lorain Salufu

Open Data

This dataset contains anonymized survey responses collected for a study on road safety assessment during construction of the Dar es Salaam Bus Rapid Transit (BRT) Phase 3 corridor. The dataset includes responses from 400 participants, together with the survey. The data were collected to assess perceived safety conditions, adequacy of construction-phase safety measures, effectiveness of traffic diversions, and the effects of construction activities on road users and nearby communities. No personally identifiable information is included in the shared files.

Smart Dynamic Concrete: Effect Of Coarse Aggregate Size Distribution On Fresh, Mechanical And Durability Properties, Venu Sipelli, Kamineni Aditya, Shravya Sripadapu

Mansoura Engineering Journal

SDC is a self-flowing concrete that demonstrates improved material efficiency through optimized aggregate gradation. Unlike SCC, which relies on high powder content for improved flowability, SDC provides improved flowability by optimized aggregate gradation, making it a promising alternative to SCC. This paper presents the fresh, mechanical, and durability performance of M40-grade SDC using OPC 53 grade cement, GGBS, CRF, and polycarboxylate-based superplasticizer. A constant cementitious content of 470 kg/m³ and water–cement ratio of 0.38 were maintained. The fresh, mechanical, and durability performances of SDC using three types of coarse aggregate combinations, namely, 70% 10 mm + 30% 20 mm, 75% …

Data-Driven Prediction Of Compressive Strength In Pofa-Modified Concrete: A Comparative Study Of Lr, Nlr, And Ann Models, Shuaaib A. Mohammed, Hawdin Ismael Ibrahim, Diar Fatah Abdulrahman Askar, Hersh F Mahmood, Mehdi Khodaei, Soran Abdrahman Ahmad

Mansoura Engineering Journal

Production of concrete results in high CO₂ emissions, high energy demand, and consumption of various raw materials; however, it is one of the most widely used materials in construction to date. Therefore, researchers aim to minimize the impact of concrete production through various methods, such as introducing sustainable sources of materials that can be used in concrete. For instance, agricultural waste materials can be used as partial cement replacement. This study presents a comprehensive data-driven analysis of the effects of POFA on the properties of normal-strength concrete. By synthesizing a database of 196 experimental datasets from existing literature, three …

Multi-Objective Hydro-Thermal Optimization Of Spiral Conformal Cooling Channels Using A Kriging-Cfd Framework, Soroush Masoudi, Barun K. Das, Majid Tolouei-Rad

Research outputs 2022 to 2026

This study presents a surrogate-based computational framework for the thermo-hydraulic optimization of spiral conformal cooling channels (CCCs) used in injection moulding applications. Sixteen design configurations were generated using Latin Hypercube Sampling and evaluated through CFD simulations to determine cooling time and pressure drop. Based on the simulation data, a Universal Kriging surrogate model was developed to describe the nonlinear relationships between channel diameter, helix pitch, channel-to-surface distance, and the resulting thermo-fluid performance. The predictive capability of the surrogate model was evaluated using leave-one-out cross-validation. The model showed excellent agreement for pressure drop prediction (R² ≈ 0.99) and good predictive accuracy …

Analysis Of Geosynthetic-Reinforced Tailings Dam Slopes Subjected To Surface Loads, Francis Otieno, Sanjay Kumar Shukla

Research outputs 2022 to 2026

This study presents an extensive numerical investigation of the stability of a geosynthetic-reinforced tailings dam embankment slope subjected to surface loads from retained pyrite tailings slurry upstream of the dam. The analysis was performed on an embankment with an inclination of 1V:2.5H on the upstream slope and 1V:2H on the downstream slope. The dam embankment rests directly on previously deposited pyrite tailings that have dried over time and are sufficiently consolidated to support the embankment. The variable parameters considered in this study include the geosynthetic reinforcement length across the failure zone, effective cohesion (c′), effective angle of internal friction (ϕ′), …

Fracture Energy Of Ambient-Cured Fly Ash-Based Geopolymer Concrete, Alireza Mohyeddin, Trijon Karmokar, Mohammad Fardipour

Research outputs 2022 to 2026

Fracture energy is a key parameter in current prediction models for capacity of structural anchors. During broader research on behaviour of structural anchors in ambient-cured fly ash-based geopolymer concrete, it was realised that despite extensive literature on Ordinary Portland Cement (OPC) and other types of geopolymer concrete, there is a lack of literature on fracture energy of such geopolymer concretes. The purpose of the current research is to measure this property for this specific type of concrete using Wedge Splitting Test (WST) method. This method was selected due to its stable crack propagation and suitability for small-sized specimens. The influence …

The Rise In Height And Curb Weight Of The Top-Selling Vehicles In The United States From 1991 - 2025: Implications For Engineering Design And Vulnerable Road Users, Samuel L. Steinman-Friedman

Civil Engineering Theses

Road fatalities are higher in the United States than in other high-income regions. In 2024, 39,254 people died on roads in the United States compared to 19,940 in the European Union. These two regions have comparable exposure metrics, such as population size, roadway network length, and fatalities per mile traveled. Light trucks dominate the U.S. market, whereas hatchbacks are prevalent in Europe. The trendline of the average height and curb weight of the top-selling vehicles in the United States has increased by 0.24 inches and 23.52 pounds per year since 1991. The average 2025 top-selling U.S. passenger vehicle is 7.5 …

Integrated Thermal, Energy, And Structural Performance Assessment Of A Novel In-Service Shallow Geothermal Bridge Deicing System, Alireza Fakhrabadi

Civil Engineering Dissertations

Understanding the performance of bridge deck deicing systems under winter weather conditions is important for improving transportation safety and reducing long-term deterioration of bridge infrastructure. Bridge decks are more vulnerable to icing than ground-supported pavements because they are exposed to ambient air, wind, and radiation from multiple directions, while they do not receive thermal support from the underlying soil. Conventional deicing methods, especially chloride-based salts, can reduce ice formation in the short term, but repeated application may accelerate reinforcement corrosion, concrete damage, and environmental concerns. Therefore, shallow geothermal energy has been considered as a sustainable alternative for bridge deck deicing …

Design And Fabrication Of A Scaled Automated Dairy Farm Model: A Report, Md Towfiqur Rahman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Summary

This study investigates how ventilation systems work in dairy barns and builds a scaled model to support education and research. The project is designed to help students from the University of Nebraska–Lincoln (UNL), K-12 learners, and researchers in animal science, veterinary medicine, and engineering gain visual experience with dairy facility components and processes. Different ventilation methods were studied, leading to the design of a 1/64-scale tunnel-ventilated dairy barn meant for 60 Holstein Friesian cows. Barn dimensions were set based on real Holstein cow measurements to ensure proper cow comfort, while airflow requirements were calculated and scaled down. Miniature fans …

Effects Of Metals On Persulfate Activation For The Decomposition Of Pfas, Malu Deav Devadasan

Civil Engineering Dissertations

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely used in industrial and consumer products due to their unique physicochemical properties. Their resistance to degradation, potential for bioaccumulation, and associated adverse health effects have prompted increasing regulatory attention, including the establishment of drinking water standards for six PFAS compounds by the U.S. Environmental Protection Agency in 2024.

Current PFAS treatment technologies are often energy-intensive and costly or generate secondary waste streams requiring further management. Meanwhile, this research investigated transition metal-catalyzed advanced oxidation processes for PFAS decomposition in water under ambient conditions. Previous studies demonstrated effective degradation of perfluorocarboxylic acids …

Heat-Related Injuries And Fatalities In Roofing: Osha Investigations From 2003-2024, Kenneth S. Sands Ii, Benjamin Marshall

The Professional Constructor

This study examines 52 heat-related roofing incidents recorded by the Occupational Safety and Health Administration (OSHA) between 2003-2024 to describe patterns in outcomes and identify trade-specific prevention opportunities. Researchers built a structured dataset from OSHA investigation summaries and analysed frequencies of the incidents and their associations with month, time of day, project type, end use, and age to complement a thematic review of narrative abstracts. Fifty-eight percent of cases were fatalities, with the remainder split between hospitalized and non-hospitalized injuries; these statistics underscore the consequences of heat events that trigger OSHA reporting. There was a clear relationship between number of …

Reliability-Based Performance Evaluation Of Slurry Wall For Leakage Control At Chakaria Landfill, Bangladesh, Shishir Bhandari

Civil Engineering Theses

Landfill leachate threatens groundwater quality in low-lying coastal Bangladesh, where a shallow water table and a discontinuous natural clay barrier heighten contamination risk beneath municipal solid waste sites. At the Chakaria Landfill in Cox's Bazar District, a cement-bentonite slurry wall was proposed as a vertical cutoff to control seepage, but its reliability under the site's high-groundwater condition had not previously been evaluated in probabilistic terms.

This study evaluated the wall's performance using a two-dimensional SEEP/W finite-element seepage model, a validated response surface (RSM) equation relating seepage rate to wall permeability, thickness, depth, and a Hasofer-Lind first-order reliability (FORM) analysis built …

Perception Of Transportation Challenges And Their Influence On Mode Choice In A Small Us City: A Generalized Structural Equation Modeling Approach, Anindya Kishore Debnath, Suman Kumar Mitra

Civil Engineering Faculty Publications and Presentations

This study profiles individuals encountering transportation challenges by analyzing factors influencing their perceptions and how they affect mode choice decisions in Fort Smith, Arkansas. Using primary travel survey data, we estimated a multinomial logit (MNL) within a Generalized Structural Equation Model (GSEM) that controls for residential self-selection and car ownership endogeneity. We find that individuals from low-income households are more likely to perceive transportation challenges, particularly due to a lack of a car and inadequate public transport. Higher household car ownership generally diminishes perceived challenges, except regarding limited bike lanes. Weekend or late-shift workers are more likely to own cars …

Calcium Based Carbon Negative Fillers And Additives: Effects On Hydration And Performance Of Low-Carbon Cement Systems, Smita Bhowmick Shithi

Masters Theses

Cement production is a major source of global CO₂ emissions creating an urgent need for carbon-negative fillers and functional additives that lower clinker use while maintaining cement performance. This thesis investigates the effects of organic mineral salts as fillers and additives on cement hydration, fresh properties, compressive strength and pore structure. In the first study, ordinary Portland cement (OPC) was partially replaced with calcium carbonate or calcium oxalate to enable a direct comparison under controlled particle size distribution (PSD). Rheology, flowability, hydration kinetics, phase evolution, mechanical performance and water absorption were evaluated. Calcium carbonate promoted early hydration through nucleation and …

Investigating The Dynamic Rating Method: Effects Of Flood Wave Geometry On Discharge Estimation, Daniel James Read

Masters Theses

Rating curves are a vital tool to convert from observed stage to discharge in streamflow monitoring. Most gaging sites utilize a simple rating curve, which assumes a monotonic relationship between stage and discharge. In most cases, this assumption is valid; however, dynamic effects of flood waves often cause significant error in discharge estimation for mildly sloped streams. The dynamic rating method utilizes a numerical solution of the St. Venant Equations applied to time series stage data to compute discharge. Within this method, there is a flood wave parameter called the flood wave factor. The researchers designed a formal computational model …

Castrip Process Technology: Non-Grain Oriented (Ngo) Si Steels Extension And Carbide-Free Bainitic (Cfb) For Flat Products, Naram Naidu Meesala

Masters Theses

"This research explores the development of advanced steel grades manufactured through Castrip® twin-roll thin strip casting technology, with particular attention to non-grain-oriented electrical Si-Steels (NGOES) and carbide-free bainitic (CFB) steels. The Castrip® process offers a near-net-shape route for producing thin steel strips, which greatly decreases the number of processing stages, lowers energy demand, and reduces carbon dioxide emissions when compared with traditional steel production methods.

In the NGOES part of the study, several industrial Fe–Si steel compositions were cold rolled to final thicknesses ranging from 0.35 mm to 0.15 mm. These materials were then exposed to short-duration continuous annealing at …

A Novel Federated Llm Framework For Distributed Traffic Modelling In Intelligent Transportation Systems, Seerat Kaur

Theses and Dissertations (Comprehensive)

Intelligent transportation systems (ITS) depend on accurate traffic prediction to support congestion management, infrastructure planning, and real-time operational decisions. Despite substantial progress in data-driven forecasting, several challenges continue to limit practical deployment: traffic data is distributed across independent regional authorities, making centralized aggregation infeasible, standard federated aggregation strategies ignore traffic-specific characteristics that meaningfully affect model quality, and existing models produce only numerical outputs without interpretable reasoning that urban planners can act upon. This thesis addresses these challenges through four contributions that collectively advance privacy-preserving, explainable, and scalable traffic forecasting.

The first contribution provides a systematic review of 129 peer-reviewed publications, …

Assessing Dissolved Organic Matter Sources And Dynamics In Urban Stormwater: Implications For Greenhouse Gases, Harper W. Schmalz

Theses and Dissertations (Comprehensive)

Stormwater management ponds (SWMPs) are important aspects of land-use planning and increasingly recognized as active sites of biogeochemical processing that influence carbon cycling; however, little research has investigated the controls on dissolved organic and dissolved inorganic carbon (DOC and DIC) within these systems. This thesis examined the processing and transformations of dissolved carbon between three compartments to support the development of a greenhouse gas (GHG) box-model for urban stormwater ponds, including SWMP sediment, surface water, and vegetation. The objective of this thesis was to assess the biogeochemical processes that govern the rate and transformation of DOC and DIC between these …

Critical Parameters Controlling Oxide Scale Formation And Hydro-Descaling Efficiency During Steelmaking, Tochukwu Princewill Ojiako

Doctoral Dissertations

In modern steelmaking, cast slabs are exposed to high-temperature oxidizing environments during secondary cooling, reheating, and hot rolling, resulting in the formation of multilayer oxide scales on the steel surface. These scales interact with mold-flux residues originating from the casting process (CC). The morphology, chemistry, and adhesion of oxide scale strongly influence its removability during high-pressure hydraulic descaling and ultimately determine the surface quality of hot-rolled products. However, the mechanistic relationship between oxide scale evolution, scale-steel interfacial structure, and hydraulic descaling performance remains poorly understood.

This dissertation investigates oxide scale formation, modification, and removal in low-carbon thin-slab steels produced by …

Quantifying, Forecasting, And Mitigating Construction Labor And Material Challenges In A Dynamic Global Economy Using Econometrics And Deep Learning, Ahmed Gamal Elsayed Mohamed Shiha

Doctoral Dissertations

"The construction industry contributes to the global economy, yet its cost management practices remain constrained by labor shortages and material price volatility. These challenges are intensified by economic disruptions, geopolitical tensions, and trade policy shifts. Despite a growing body of literature, five knowledge gaps remain unaddressed: (1) the absence of dynamic, and localized measures of construction labor shortages; (2) limited empirical investigation of macroeconomic leading indicators of labor shortages; (3) underutilization of deep learning (DL) algorithms in forecasting local construction labor earnings; (4) the limited treatment of structural breaks in existing construction material price forecasting models; and (5) the lack …