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Adsorption potentials of iron-based metal–organic framework for methyl orange removal: batch and fixed-bed column studies
No full textIn the present work, continuous fixed-bed column and batch studies were undertaken to investigate the efficiency of iron-based metal–organic framework (Fe-BTC) for the removal of methyl orange as a model contaminant from aqueous solutions. The batch experiments were carried out by varying operational parameters such as adsorbent dosage, pH, temperature, and initial contaminant concentration. The results showed that Fe-BTC had a high removal efficiency under a wide pH range. The equilibrium data were best fitted by the Langmuir model with a maximum adsorption capacity of 100.3 mg g-1 at 298 K. In order to assess the industrial feasibility of Fe-BTC, fixed-bed column studies were conducted to obtain breakthrough curves, breakthrough and saturation times, and maximum uptakes at different bed heights. The breakthrough time was 20.0 and 46.2 h at 0.75 and 1.5 cm bed depths, respectively. The bed removal efficiency was 35.2 and 46.7% at 0.75 and 1.5 cm bed depth, respectively. The bed maximum adsorption capacity was 20.2 and 21.6 mg/g at 0.75 and 1.5 cm bed depths, respectively. Moreover, the application of empirical breakthrough curve models showed good agreement with the modified dose response model (R2> 0.99). Also, the analytical solution of the advection–dispersion–adsorption mass transfer equation showed an excellent fit to the experimental breakthrough data (R2> 0.99). Further, the analytical model was utilized to predict the length of the mass transfer zone as a function of the bed depth and to construct a 3D surface plot that can be utilized to predict the breakthrough at different bed depths
Performance of BFRP RC beams using high strength concrete
No full textThis research investigates the flexural behavior and serviceability performance of basalt fiber-reinforced polymer (BFRP) reinforced concrete (RC) beams cast with normal- and high-strength concretes (NSC and HSC). Carbon FRP (CFRP) and steel-reinforced concrete beams were also included for comparison purposes. Four-point bending tests were performed on a total of 14 slender beams with dimensions of 180 mm × 230 mm × 2200 mm. The main aim was to examine the improvement in the performance of BFRP RC beams using HSC and to assess its compatibility with the recommendations and guidelines of the ACI440 Code. The test results were reported and discussed in terms of flexural capacity, deflection, crack width, reinforcement and concrete strains, and failure modes. The results revealed that the flexural capacities of BFRP beams were slightly underestimated by ACI440.1R-15 while reasonable predictions were observed for the cracking moments in HSC and NSC. The use of HSC as compared to NSC enhanced the cracking and ultimate moments of all BFRP RC beams by 10% and 16%, respectively. Furthermore, the average bond-coefficient (Kb) value for BFRP-RC beams was found to be 0.70 which is much lower than the conservative Kb value suggested by the ACI440 guidelines for sand-coated FRP bars.American University of Sharja
A Framework for Assessing Commitment Indicators in Sustainable Development Decisions
No full textNumerous decision support systems have been developed to address the decision-making process in organizations. However, there are no developed mechanisms to track commitment down the line to the decisions made by corporate leaders. This paper is a portion of a study that establishes a framework for a comprehensive metric system to assess commitment to Sustainable Development (SD) decisions down the line in capital projects, and sets the groundwork for further development of performance indicators for SD outcomes. This ultimately leads to investigating the relationship between commitment to corporate decisions and better project performance in SD parameters. Hence, this study explores the literature to extract relevant parameters that reflect the degree of the project participants’ commitment to SD decisions and to develop commitment indicators. The study created then validated an index to track this commitment along the project stages: the Sustainable Development Commitment Tracking Tool (SDCTT). The SDCTT was tested on an infrastructure project case study. In this paper, techniques relevant to the first stage of projects (planning and definition) are presented. The SDCTT is the groundwork for the future development of performance indicators for SD outcomes, and within the postulated model should ultimately contribute towards reducing project waste, energy use, and carbon emissions
Modeling, design, and implementation of a bio-inspired propulsion mechanism for underwater vehicles
No full textA Master of Science thesis in Mechatronics Engineering by Mohamad Omari entitled, “Modeling, design, and implementation of a bio-inspired propulsion mechanism for underwater vehicles”, submitted in April 2021. Thesis advisor is Dr. Mehdi Ghommem and thesis co-advisor is Dr. Lotfi Romdhane. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Recent advances in bio-robotics research and smart materials have boosted the development of bio-inspired autonomous underwater vehicles (AUVs) to replace their conventional counterparts driven by rotary propellers. These vehicles can serve in several applications including marine environment exploration, search and rescue, military surveillance, and border patrol. In this Thesis, we investigate the hydrodynamic performance of robotic fish tail inspired from three different fish species, namely the big-eye trevally, the butterfish, and the boxfish. A detailed CAD model of the robotic fish is developed and simulated using the MATLAB tool Simscape Multibody. The bio-inspired propulsion mechanism consists of three articulated segments actuated by servomotors and a caudal fin to produce the desired fish wavy motion. A testing platform, equipped with load cell and distance laser sensor, is developed to measure the produced thrust and associated forward speed over a range of undulation frequencies and lateral amplitude of tail oscillations. The experimental results showed good agreement with Lighthill’s theory of elongated-body propulsion. Then, a comparative study is conducted to examine the swimming capabilities of the aforementioned fish species. The boxfish was found the slowest of the three species, with a mean thrust of 6.46 mN and a forward speed of 10.2 cm/s. This reflects the characteristics of the boxfish being a reef fish, which is best suited for tight maneuvering and bursts of speed rather than a long sustained cruising speed. The trevally is observed to produce the fastest swimming with an estimated forward speed of 25.2 cm/s. The experimental results are also compared to previous studies on robotic fish reported in the literature.College of EngineeringMultidisciplinary ProgramsMaster of Science in Mechatronics Engineering (MSMTR
Evaluation of refined cement-based matrix systems for extrusion of wood fiber cement
No full textDifferent cementitious matrix formulations incorporating various chemical, polymeric and mineral additives were evaluated for use in extruded fiber cement products. These alternative formulations were designed to enhance the end product performance characteristics under aging conditions and to facilitate the extrusion process. The impact of different matrix formulations on mechanical, durability and physical characteristics of extruded cellulose fiber cement products were compared. Test results show that most of the additives lowered the bulk specific gravity but increased the moisture absorption capacity of extruded fiber cement products when compared with the basic mix formulation. Generally, the additives caused drop in flexural strength but did not significantly affect the flexural toughness of the matrix formulations. Upon saturation the frictional pull-out of swollen fibers increased the ductility (deformation) capacity of extruded cellulose fiber cement products. These results provide further insight into performance characteristics of extruded cellulose fiber cement products, and help with selection of matrix mix formulations to meet performance requirements of a particular application.United States Department of Agricultur
Physical and Corrosion Properties of CoCrNi Medium Entropy Alloy Thin Films
No full textA Master of Science thesis in Mechanical Engineering by Omer Fathalrahman Mohamed entitled, “Physical and Corrosion Properties of CoCrNi Medium Entropy Alloy Thin Films”, submitted in November 2021. Thesis advisor is Dr. Wael Abuzaid and thesis co-advisor is Dr. Mehmet Egilmez. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Multi-principal element alloys (MPEA) have garnered significant research interest in the last decade due to their desirable physical and mechanical properties which defy well-known trends. This thesis considers the equiatomic CoCrNi alloy, a typical multi-principal element alloy, which in bulk form, has shown superior mechanical properties in addition to excellent oxidation and corrosion resistance. Such a combination of desirable characteristics motivates further research into the potential use of CoCrNi in thin-film form for various applications. This work aims to grow and optimize the deposition parameters of CoCrNi thin films and investigate their influence on the physical properties. In addition, the corrosion properties of the films as a function of thickness will be studied. The CoCrNi medium entropy alloy thin films were deposited onto Si/SiO₂ substrates by direct current (DC) magnetron sputtering at different substrate temperatures and working gas pressures using a pre-alloyed target. The equiatomic polycrystalline composition was obtained at optimized pressure (2 mTorr) and temperature (400 °C). The electrical and magnetic properties were measured and contrasted with the physical properties of the bulk CoCrNi. The obtained magnetic properties indicate stabilization of the ferromagnetic phase in CoCrNi thin films. Anomalous Hall effect has been observed for all studied films. To study the corrosion behavior, the polycrystalline thin films, 225 nm - 600 nm thickness range, were deposited on mild steel substrates and the corrosion characteristics were investigated in 3.5 wt. % NaCl solution. The corrosion rates were determined for CoCrNi in both, bulk and thin-film form. At relatively small thicknesses, the CoCrNi films result in significant improvement in corrosion resistance, and the highest efficiency achieved relative to the mild steel was 94.79%. In summary, this thesis shows that deposition conditions (e.g., substrate temperature and working pressure) can be utilized to control the microstructure and tailor the physical properties of MPEA thin films for desired applications. For example, and as shown in this work, through proper optimization of CoCrNi thin film composition and thickness, superior corrosion properties can be attained which allow for a considerable enhancement in the performance of widely utilized mild steels.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME
Zn-Cu Metal-Organic Framework on Cu-Foam Substrate as a Pseudocapacitive Electrode in Asymmetric Supercapacitor Towards Enhanced Energy Density
No full textA Master of Science thesis in Chemical Engineering by Halima Ali Sulaiman Khalfan Alnaqbi entitled, “Zn-Cu Metal-Organic Framework on Cu-Foam Substrate as a Pseudocapacitive Electrode in Asymmetric Supercapacitor Towards Enhanced Energy Density”, submitted in April 2021. Thesis advisor is Dr. Sameer Al-Asheh and thesis co-advisor is Dr. Mohammad Ali Abdelkareem. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).College of EngineeringDepartment of Chemical EngineeringMaster of Science in Chemical Engineering (MSChE
Developing a Model for Selecting Smart Contractors
No full textA Master of Science thesis in Civil Engineering by Maryam Wasef Al Nabulsi entitled, “Developing a Model for Selecting Smart Contractors”, submitted in May 2021. Thesis advisor is Dr. Sameh El-Sayegh. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).The recent advances in the construction industry, in terms of the use of automation and technology, necessitate the need for smart contractors who are capable of delivering construction projects successfully. Selection of incompetent contractors may jeopardize achieving project’s objectives. Current contractor selection methods focus on selecting the lowest bidder. However, the lowest bidder may not be equipped with the right tools and smart practices, which increases the risks of project failure. This thesis aims to develop a new bidding model for contractor’s selection that integrates the use of the smart practices and the original bid price. Sixteen smart construction practices were identified through review of related literature. These were categorized into four groups. A questionnaire was developed and distributed to construction professionals to assess the importance of these practices. Sixty responses were received. The weights of these practices were assessed using the Analytic Hierarchy Process (AHP). The most essential selection group is the “Smart Construction Process” group with a global weight of 0.366, followed by the “Smart Organization” group (0.321), the “Smart Construction Support” group (0.204) and lastly, the “Smart Office Support” group (0.139). The top five smart practices are: smart construction methods (0.140), smart vision (0.126), smart strategy (0.112), smart construction material (0.079) and smart communication (0.077). The average value of the smart construction practices relative to the total construction costs of the project was found to be 30%. This shows the high value that experts place on smart practices. A new A+SC model is proposed, where A represents the bid price and SC represents the monetary value of smart practices. The value of smart practices is considered as a negative value to act as an incentive for contractors. The owner selects the bidder with the lowest Total Combined Bid (TCB). The proposed model motivates contractors to implement smart construction practices to reduce their TCB and increase their chances of winning bids. The development of such model will immensely help the decision makers in selecting the most qualified and smart bidders. A hypothetical case study was performed to validate the proposed model and demonstrate its use.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Where Islamic Visual Theory and Western Pictorial Tradition Meet: 360° Panoramic Photography’s Two-Dimensional Image Projections and Sacred Spaces
No full textUsing this author's ongoing project Sacred Spaces of New England and Hans Belting's book Florence and Baghdad: Renaissance Art and Arab Science as starting points, this paper compares and contrasts Islamic visual theory with Western pictorial tradition and examines Islamic pattern design to root this author's 360° panoramic photography's two-dimensional geometric image projections of sacred spaces into an artistic tradition
The Language of Counter-Arguments and Support Arguments in Argumentative Student Writing
No full textA Master of Arts thesis in Teaching English to Speakers of Other Languages (TESOL) by Noor Wafic Kaddoura entitled, “The Language of Counter-Arguments and Support Arguments in Argumentative Student Writing”, submitted in May 2021. Thesis advisor is Dr. Philip McCarthy. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).This study analyzes the linguistic features of counter-arguments and support arguments using two computational linguistic tools: Coh-Metrix and Gramulator. The research question investigates whether counter-argument paragraphs and support paragraphs are different in terms of their linguistic features. To conduct this study, a corpus of 78 argumentative papers was collected. The paragraphs in the papers were categorized in terms of their function. The categories included functions of Support, Counter-argument, Expostulation, Counter-argument and Expostulation, Background, and Other. The paragraphs were analyzed for their readability and writing quality through Coh-Metrix. With the exception of the measure of Deep Cohesion, the Coh-Metrix results suggest minimal differences in terms of readability and writing quality between counter-argument and support paragraphs. Following the Coh-Metrix analysis, both counter-argument and support corpora were analyzed through Gramulator for their lexical features. The Gramulator results suggest the presence of causal language, fixed expressions in counterarguments, as well as some tagged language in support arguments.College of Arts and SciencesDepartment of EnglishMaster of Arts in Teaching English to Speakers of Other Languages (MA TESOL