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Theses

2021

Articles 1 - 8 of 8

Full-Text Articles in Civil and Environmental Engineering

The Impact Of Wastewater Chemistry And Flow Characteristics On Hydrogen Sulfide Concentration, Mohsina Muhammed Sherief Dec 2021

The Impact Of Wastewater Chemistry And Flow Characteristics On Hydrogen Sulfide Concentration, Mohsina Muhammed Sherief

Theses

Hydrogen sulfide (H2S) is a naturally occurring, highly toxic gas that is formed from the decomposition of sulfur compounds. At low concentrations, H2S is an irritant for the eyes, respiratory and gastrointestinal tract. At higher H2S concentrations, it produces neurological impairment with dizziness, headache, and loss of consciousness. Mortality was reported to reach 6 percent following exposure to elevated concentrations. H2S is generated in different industrial processes. In wastewater collection and treatment plants, H2S is a common source of concrete and metal corrosion that has resulted in huge economic loss. …

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Strengthening Of Concrete Deep Beams Using Carbon Fabric Reinforced Cementitious/Geopolymeric Matrix, Nour Mohamed Muhsen Khir Allah Nov 2021

Strengthening Of Concrete Deep Beams Using Carbon Fabric Reinforced Cementitious/Geopolymeric Matrix, Nour Mohamed Muhsen Khir Allah

Theses

This research aimed to examine the effectiveness of using carbon fabric-reinforced matrix (C-FRM) composites to improve the shear response of reinforced concrete (RC) deep beams. Ten RC deep beams with a/h of 1.6 were tested, where a is the shear span and his is the beam depth. Test parameters included the presence of internal shear reinforcement (no shear reinforcement and minimum shear reinforcement), number of C-FRM composite layers (one and two layers), angle of inclination of the second layer of CFRM (90o and 0o with respect to the longitudinal direction of the beam), and type of matrix (cementitious and geopolymer). …

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Environmental Assessment Of The Impact Of Land-Based Discharges On Marine Water And Sediment Quality In Dubai, Uae, Ayman Fathy Halawa Sep 2021

Environmental Assessment Of The Impact Of Land-Based Discharges On Marine Water And Sediment Quality In Dubai, Uae, Ayman Fathy Halawa

Theses

The current seawater and Creek – Canal waterway in the Emirate of Dubai, UAE, is under tremendous pressure because of continuous urban water discharges from land-based sources. Therefore, the impact of urban water discharges on marine water and sediment quality in the Emirate requires a thorough assessment. The main objective of this study is to assess the impacts of effluent discharges on the quality of water and sediment in the open sea and Dubai Creek. The land-based sources include the power and desalination plants, industrial sector, sewage treatment plant, and stormwater runoff. To achieve the stated objective, relevant data on …

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Comprehensive Characterization Of The Aerosol And Cloud Condensation Nuclei In The Uae, Farah Hassan Abdi Jun 2021

Comprehensive Characterization Of The Aerosol And Cloud Condensation Nuclei In The Uae, Farah Hassan Abdi

Theses

Cloud seeding has emerged as a significant alternative freshwater source in the United Arab Emirates (UAE). It is employed to manipulate weather conditions and increase precipitation in specific target regions. These efforts aim to densify clouds and enhance the likelihood of rainfall by inducing nucleation. This technique involves an operational crew aboard an aircraft that disperses substantial quantities of seeding particles, such as salts or silver iodide, into suitable clouds. These particles can serve as cloud condensation nuclei (CCN) and indirectly affect the rate of rainfall. In 2018, cloud seeding operations were responsible for approximately 10-15% of the UAE's total …

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Performance Of Ultrasound-Assisted Forward Osmosis Membrane Process In Desalination Of Seawater, Bara Awwad Al-Sakaji May 2021

Performance Of Ultrasound-Assisted Forward Osmosis Membrane Process In Desalination Of Seawater, Bara Awwad Al-Sakaji

Theses

The objective of this study was to investigate the effect of using ultrasound on water flux through forward osmosis membrane when applied for seawater desalination. A synthetically prepared solution simulating seawater characteristics was used. Parameters considered in the investigation included membrane cross-flow velocity (0.25 and 1.0 cm/s), flow configuration (co-current versus counter-current), direction of ultrasound waves relative to the membrane side (active layer versus support layer), and type of draw solution (NaCl versus MgCl2). Furthermore, a two-level factorial design was considered in the analysis of the results obtained from the experimental work. This study revealed that applying a …

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Behavior Of Steel Fiber-Reinforced Geopolymer Concrete Made With Recycled Concrete Aggregates, Abdalla Ahmed Moallim Hussein Apr 2021

Behavior Of Steel Fiber-Reinforced Geopolymer Concrete Made With Recycled Concrete Aggregates, Abdalla Ahmed Moallim Hussein

Theses

Industrial by-products and recycled concrete aggregates (RCA) have the potential to fully replace cement and natural aggregates, respectively, in the production of concrete rather than being discarded wastefully into landfills or stockpiles. Yet, their combined use in the development of a novel RCA geopolymer concrete has been limited to nonstructural purposes, owing to the inferior mechanical and durability properties of said concrete. To improve the properties of geopolymer concrete made with RCA, steel fibers may be added to the mix. This research aims to study the feasibility of reutilizing locally available industrial solid wastes and RCA in geopolymer concrete for …

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Performance Evaluation Of Cement-Free Geopolymer Concrete Made With Recycled Concrete Aggregates And Steel Fibers, Jamal Ahmad Samer Medljy Apr 2021

Performance Evaluation Of Cement-Free Geopolymer Concrete Made With Recycled Concrete Aggregates And Steel Fibers, Jamal Ahmad Samer Medljy

Theses

Sustainable and innovative alternatives have been investigated to replace concrete’s main components, natural aggregates, and cement. Previous studies have been carried out to replace NA and cement with recycled concrete aggregates (RCA) and inorganic alkali-activated geopolymer binders, respectively. Yet, such sustainable concrete has only been proposed for non-structural purposes, owing to the inferior properties of RCA. This research work aims to assess the feasibility of reutilizing RCA from construction and demolition waste and locally available industrial solid by-products in the production of sustainable geopolymer concrete for structural applications. The binding materials were either in the form of a single precursor, …

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Performance Of Cement-Free Geopolymer Concrete Made With Ceramic Waste Powder Using Taguchi Method, Ponalagappan Chokkalingam Apr 2021

Performance Of Cement-Free Geopolymer Concrete Made With Ceramic Waste Powder Using Taguchi Method, Ponalagappan Chokkalingam

Theses

The ceramic industry produces a substantial amount of waste during its production processes. Recycling and reutilizing such ceramic waste is a challenge due to its extended biodegradation period. Consequently, the ceramic industry is dedicated to attaining a sustainable solution to dispose of this waste rather than discarding it wastefully into landfills or stockpiles. In turn, the demand for ordinary Portland cement has been on a steady increase, leading to concerns about the sustainability of the construction industry. As a sustainable alternative to cement, alkali-activated binders have been proposed owing to their ability to reduce carbon emissions, preserve nonrenewable natural resources, …

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