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Lehigh University

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Full-Text Articles in Engineering

Computational Study Of Water Desalination Using Direct Contact Membrane Distillation, Anas Mohammed Alwatban Jan 2019

Computational Study Of Water Desalination Using Direct Contact Membrane Distillation, Anas Mohammed Alwatban

Theses and Dissertations

Computational fluid dynamics simulations were conducted to study the unit performance of direct contact membrane distillation for seawater desalination process in three-dimensional modules. A parametric study was conducted to assess the effects of the mem


Cmos Closed-Loop Control Of Mems Varactors, Mohammad Javad Asadi Jan 2019

Cmos Closed-Loop Control Of Mems Varactors, Mohammad Javad Asadi

Theses and Dissertations

A closed-loop capacitance sensing and control mix-mode circuit with a dedicated sensor electrode and a proportional-integral controller was designed for MEMS varactors. The control was based on tuning the bias magnitude of the MEMS varactor according to t


Development Of Hybrid Ion Exchange Processes Driven By Carbon Dioxide (Hix-Co2), Hang Dong Jan 2019

Development Of Hybrid Ion Exchange Processes Driven By Carbon Dioxide (Hix-Co2), Hang Dong

Theses and Dissertations

Freshwater scarcity is severely faced by humans even though our planet is full of water,being more than 97% of the water is salty water such as seawater or brackish water. Andsome of the brackish water is impaired by various of contaminants, such as nitra


An Investigation Of Enhanced Additive Manufacturing Incorporating Spatial Performance Property Control Throughout Printed Products, Alaauldeen Ali Duhduh Jan 2019

An Investigation Of Enhanced Additive Manufacturing Incorporating Spatial Performance Property Control Throughout Printed Products, Alaauldeen Ali Duhduh

Theses and Dissertations

The overall objective of this research is to investigate and develop a novel additive manufacturing technique that enables additive manufacturing to make products with customizable and gradient properties to match the consumer’s needs. This research inten


Optimization Algorithms For Machine Learning Problems, Hiva Ghanbari Jan 2019

Optimization Algorithms For Machine Learning Problems, Hiva Ghanbari

Theses and Dissertations

In the first chapter of this thesis, we analyze the global convergence rate of a proximal quasi-Newton algorithm for solving composite optimization problems, in both exact and inexact settings, in the case when the objective function is strongly convex. W


Neural Network Methods For Nonparametric Probabilistic Forecasting, Konstantinos Miltiadis Hatalis Jan 2019

Neural Network Methods For Nonparametric Probabilistic Forecasting, Konstantinos Miltiadis Hatalis

Theses and Dissertations

The presented research investigates the use of neural networks for probabilistic forecasting in selected application areas. The topic of neural networks, also known as deep learning, has exploded as a research field, showing incredible results in image an


Development Of High-Speed Optical Coherence Tomography For Time-Lapse Non-Destructive Characterization Of Samples, Yongyang Huang Jan 2019

Development Of High-Speed Optical Coherence Tomography For Time-Lapse Non-Destructive Characterization Of Samples, Yongyang Huang

Theses and Dissertations

Optical coherence tomography (OCT) is an established optical imaging modality which can obtain label-free, non-destructive 3D images of samples with micron-scale resolution and millimeter penetration. OCT has been widely adopted for biomedical researches,


An Investigation Of Micro And Nanoscale Molding For Biomedical Applications, Ali A. Rajhi Jan 2019

An Investigation Of Micro And Nanoscale Molding For Biomedical Applications, Ali A. Rajhi

Theses and Dissertations

In the last decade, there has been rapid advancement of micro and nano manufacturing. Microinjection molding is a cost-effective fabrication technique that can fulfill the requirements of many medical applications. Despite the many advancements of microin


Advancement Of The Hybrid Ion Exchange Nitrogen And Phosphate (Hix-Np) Recovery From Waste Water And A New Approach To Brine-Free Nitrate Removal, Chelsey Shepsko Jan 2019

Advancement Of The Hybrid Ion Exchange Nitrogen And Phosphate (Hix-Np) Recovery From Waste Water And A New Approach To Brine-Free Nitrate Removal, Chelsey Shepsko

Theses and Dissertations

Due to rapid declining freshwater reserves worldwide, societies are reexamining approaches to maintain potable and industrial water supplies to meet the current and future demands. By utilizing wastewater, an impaired water resource that is large, resilie


Delay Performance And Cybersecurity Of Smart Grid Infrastructure, Huan Yang Jan 2019

Delay Performance And Cybersecurity Of Smart Grid Infrastructure, Huan Yang

Theses and Dissertations

To address major challenges to conventional electric grids (e.g., generation diversification and optimal deployment of expensive assets), full visibility and pervasive control over utilities' assets and services are being realized through the integration


Energy Harvesting Devices Operating Near Free Surface, Bashar Hassan Attiya Jan 2019

Energy Harvesting Devices Operating Near Free Surface, Bashar Hassan Attiya

Theses and Dissertations

Water energy harvesting devices operate near surfaces in natural flow settings. The complex flow features such as flow separation and reattachment, wake instabilities, turbulent structures, and vortex shedding may lead to complicated loading on the struct


Modeling And Analyzing A Patch Of Human Red Blood Cell By Coarse-Grained Particle Method, Orhan Kaya Jan 2019

Modeling And Analyzing A Patch Of Human Red Blood Cell By Coarse-Grained Particle Method, Orhan Kaya

Theses and Dissertations

This thesis consists of three sections. First, some background information and theories about the erythrocyte membrane are provided. Second, a coarse-grained molecular dynamics model for a patch of erythrocyte membrane is built up. Third, the mechanical responses of the patch of red blood cells to diffusion and diffusivity, tension, rupture, and shear-induced pore area are analyzed.The patch of erythrocyte membrane is validated by modeling diffusivity and determining the diffusion coefficient constant. Then, the patch of the coarse-grained erythrocyte membrane is stretched uniformly until rupture. The critical stress/strain from simulation match with those obtained in experiments in laser optical ...


Single Enzyme Synthesis And Bio-Imitation Of Functional Nanocrystals, Abdolhamid Sadeghnejad Jan 2019

Single Enzyme Synthesis And Bio-Imitation Of Functional Nanocrystals, Abdolhamid Sadeghnejad

Theses and Dissertations

Green synthesis methods of inorganic materials have gained lots of attention due to lower pollution and toxic precursors during the synthesis. One of the modern green methods of synthesis is biosynthesis in which a DNA, small peptide molecule, or amino acids plays the main role of synthesis. Biomineralization, the biosynthesis process happens in the nature by elements, has been considered as a green, low cost, and scalable method of synthesis. In comparison with conventional synthesis methods, biomineralization happens under ambient conditions in aqueous phase that can be applied for synthesis of inorganic nanostructure metal sulfide semiconductors gained interest due to ...


Solution Techniques For Non-Convex Optimization Problems, Wei Xia Jan 2019

Solution Techniques For Non-Convex Optimization Problems, Wei Xia

Theses and Dissertations

This thesis focuses on solution techniques for non-convex optimization problems. The first part of the dissertation presents a generalization of the completely positive reformulation of quadratically constrained quadratic programs (QCQPs) to polynomial optimization problems. We show that by explicitly handling the linear constraints in the formulation of the POP, one obtains a refinement of the condition introduced in Bai's (2015) Thoerem on QCQPs, where the refined theorem only requires nonnegativity of polynomial constraints over the feasible set of the linear constraints. The second part of the thesis is concerned with globally solving non-convex quadratic programs (QPs) using integer programming ...


Model Study Of The Static And Cyclic Lateral Capacity Of Finned Piles, Kepha Odhambo Abongo Jan 2019

Model Study Of The Static And Cyclic Lateral Capacity Of Finned Piles, Kepha Odhambo Abongo

Theses and Dissertations

The main objective of this thesis is to examine systematically the proposed improved performance of finned piles over monopiles when subjected to lateral static and cyclic loading. In order to achieve this objective, both physical and numerical simulations were conducted on finned and monopile and outcomes were analyzed for design recommendations. The physical tests were performed on scaled model piles at 1:100 reductions of typical wind turbine monopile foundations.The cyclic lateral load tests were conducted on the scaled down foundation models at 1g condition. Cyclic tests were conducted to evaluate the long-term performance of the finned piles under ...


Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh Jan 2019

Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh

Theses and Dissertations

Forward Osmosis is a natural phenomenon that takes places across a semi-permeable membrane when there is a concentration difference across the membrane. Pure water permeates to the highly concentrated channel until the concentration across the membrane equilibrates. In water desalination applications, the same principle is applied. Spiral-wound membrane, flat sheet, or hollow fiber module are typical configurations in forward osmosis desalination modules. The application of water desalination using forward osmosis requires the existence of two channels separated by a suitable forward osmosis membrane. Sea or Brackish water is introduced in one side while the other side has a suitable draw ...


Performance And Stability Of Cacl2·6h2o-Based Phase Change Materials, Joshua Charles Jan 2019

Performance And Stability Of Cacl2·6h2o-Based Phase Change Materials, Joshua Charles

Theses and Dissertations

Thermal energy storage is receiving increased attention as the world transitions away from fossil fuels and seeks to improve the efficiency of existing energy production systems. While higher-temperature thermal energy storage has received the majority of attention in the field, thermal energy storage at temperatures close to ambient conditions may also have some practical applications. Hydrated salt phase change materials (PCMs) store thermal energy in this temperature range and can have high gravimetric and volumetric energy storage capacities while having a very low cost. Despite the benefits of these salts, they generally suffer from supercooling, phase segregation during cycling, and ...


Distributed Algorithms In Large-Scaled Empirical Risk Minimization: Non-Convexity, Adaptive-Sampling, And Matrix-Free Second-Order Methods, Xi He Jan 2019

Distributed Algorithms In Large-Scaled Empirical Risk Minimization: Non-Convexity, Adaptive-Sampling, And Matrix-Free Second-Order Methods, Xi He

Theses and Dissertations

The rising amount of data has changed the classical approaches in statistical modeling significantly. Special methods are designed for inferring meaningful relationships and hidden patterns from these large datasets, which build the foundation of a study called Machine Learning (ML). Such ML techniques have already applied widely in various areas and achieved compelling success. In the meantime, the huge amount of data also requires a deep revolution of current techniques, like the availability of advanced data storage, new efficient large-scale algorithms, and their distributed/parallelized implementation.There is a broad class of ML methods can be interpreted as Empirical Risk ...


An End-To-End Platform For Autonomous Dynamic Soaring In Wind Shear, Corey Montella Jan 2019

An End-To-End Platform For Autonomous Dynamic Soaring In Wind Shear, Corey Montella

Theses and Dissertations

Despite advancements in our understanding of flight in modern times, birds remain unmatched when it comes to maneuverability and energy efficiency in flight; in particular seabirds like the albatross are known to travel vast distances without stopping for food by performing an aerobatic maneuver called dynamic soaring. When the maneuver is executed in the presence of a wind field that varies in strength of direction, the albatross extracts kinetic energy from the field. In this dissertation, we present an end-to-end system designed to exploit wind as the albatross does. The system we designed consists of a gliding platform outfitted with ...


Conic Optimization: Optimal Partition, Parametric, And Stability Analysis, Ali Mohammad-Nezhad Jan 2019

Conic Optimization: Optimal Partition, Parametric, And Stability Analysis, Ali Mohammad-Nezhad

Theses and Dissertations

A linear conic optimization problem consists of the minimization of a linear objective function over the intersection of an affine space and a closed convex cone. In recent years, linear conic optimization has received significant attention, partly due to the fact that we can take advantage of linear conic optimization to reformulate and approximate intractable optimization problems. Steady advances in computational optimization have enabled us to approximately solve a wide variety of linear conic optimization problems in polynomial time. Nevertheless, preprocessing methods, rounding procedures and sensitivity analysis tools are still the missing parts of conic optimization solvers. Given the output ...


Applications Of Machine Learning In Supply Chains, Afshin Oroojlooy Jan 2019

Applications Of Machine Learning In Supply Chains, Afshin Oroojlooy

Theses and Dissertations

Advances in new technologies have resulted in increasing the speed of data generation and accessing larger data storage. The availability of huge datasets and massive computational power have resulted in the emergence of new algorithms in artificial intelligence and specifically machine learning, with significant research done in fields like computer vision. Although the same amount of data exists in most components of supply chains, there is not much research to utilize the power of raw data to improve efficiency in supply chains.In this dissertation our objective is to propose data-driven non-parametric machine learning algorithms to solve different supply chain ...


Efficient Modeling Of Latent Thermal Energy Storage Systems For Optimal Design And Operational Research, Chunjian Pan Jan 2019

Efficient Modeling Of Latent Thermal Energy Storage Systems For Optimal Design And Operational Research, Chunjian Pan

Theses and Dissertations

As a booming economy drives the need for more electricity, demands on freshwater for thermoelectric power generation also grow. Facing the limited freshwater resources, alternative dry cooling technologies such as air cooled condensers (ACCs) that reduce water consumption are becoming more prevalent. However, the performance of air ACCs is seriously deteriorated at ambient temperature. To address this challenge, a novel application of a Phase Change Material (PCM) based cooling system for supplementary cooling of ACCs is proposed. One of the engineering challenges that prevent the commercial application of latent thermal energy storage (LTES) systems is the lack of computationally efficient ...


Analysis Of Movement Of A 3t3 Cell With A Lamellipodium On A Substrate With Variable Rigidity, Alan Wopperer Jan 2019

Analysis Of Movement Of A 3t3 Cell With A Lamellipodium On A Substrate With Variable Rigidity, Alan Wopperer

Theses and Dissertations

Live cells move in the body in response to physiological and mechanical stimuli. Cells move using lamellipodium which extend beyond the leading edge of the cell. This lamellipodium is part of the cytoskeleton of the cell which pulls the cell forward in cell migration. It is observed that cells will move directionally depending on the stiffness of the substrate the cell comes into contact with. It is hypothesized that cells probe their environment to test the stiffness of their substrate. As a cell comes into contact with a substrate, the resulting force is dependent on how rigid or soft the ...


Distributed Methods For Composite Optimization: Communication Efficiency, Load-Balancing And Local Solvers, Chenxin Ma Sep 2018

Distributed Methods For Composite Optimization: Communication Efficiency, Load-Balancing And Local Solvers, Chenxin Ma

Theses and Dissertations

The scale of modern datasets necessitates the development of efficient distributed opti- mization methods for composite problems, which have numerous applications in the field of machine learning. A critical challenge in realizing this promise of scalability is to develop efficient methods for communicating and coordinating information between distributed ma- chines, taking into account the specific needs of machine learning algorithms. Recent work in this area has been limited by focusing heavily on developing highly specific methods for the distributed environment. These special-purpose methods are often unable to fully leverage the competitive performance of their well-tuned and customized single machine counterparts ...


Hybrid Ion Exchange Processes For Sustainable Softening And Marcellus Flowback Treatment, Jinze Li Aug 2018

Hybrid Ion Exchange Processes For Sustainable Softening And Marcellus Flowback Treatment, Jinze Li

Theses and Dissertations

Hybrid ion exchange technology has been applied in many environmental aspects nowadays due to its high treatment efficiency, reusability, customizable selectivity, operational stability, and low cost. Under certain circumstances, ion exchange technology is a favorable substitute for traditional treatment process, and its applications in industries are continually growing.Water hardness is a concern for many industrial and municipal unit operations, which could result in surface scaling of heat transfer equipment or membranes. Sodium exchange softening, although commonly used, has caused serious pollution to local ecological and water environments due to its discharge of high salinity spent regenerant. Many arid areas ...


Fixed Bed Reactor Design For Thermochemical Energy Storage Using Ca(Oh)2 /Cao, Qasim Ranjha Aug 2018

Fixed Bed Reactor Design For Thermochemical Energy Storage Using Ca(Oh)2 /Cao, Qasim Ranjha

Theses and Dissertations

Thermochemical energy storage (TCES) is an attractive mode of storing the solar energy in the form of heat to be used with concentrated solar power (CSP) plants. Thermal energy is stored/released using a reverse endothermic/ exothermic reaction. TCES offers clear advantages over the other thermal energy storage (TES) options with sensible heat storage (SHS) and latent heat storage (LHS) in terms of energy density, storage time and the temperature range for thermal energy storage. However, this technique of storing the solar power at higher temperatures is still at laboratory or pilot scale, and researchers are trying to develop viable ...


The Resilience Of Smart Energy Systems Against Adversarial Attacks, Operational Degradation And Variabilities, Parth Pradhan Aug 2018

The Resilience Of Smart Energy Systems Against Adversarial Attacks, Operational Degradation And Variabilities, Parth Pradhan

Theses and Dissertations

The presented research investigates selected topics concerning resilience of critical energy infrastructures against certain types of operational disturbances and/or failures whether natural or man-made. A system is made resilient through the deployment of physical devices enabling real-time monitoring, strong feedback control system, advanced system security and protection strategies or through prompt and accurate man-made actions or both. Our work seeks to develop well-planned strategies that act as a foundation for such resiliency enabling techniques.The research conducted thus far addresses three attributes of a resilient system, namely security, efficiency, and robustness, for three types of systems associated with current ...


Aberration Corrected Analytical Electron Microscopy Studies Of Nanometallic Catalysts, Sultan Althahban Aug 2018

Aberration Corrected Analytical Electron Microscopy Studies Of Nanometallic Catalysts, Sultan Althahban

Theses and Dissertations

Catalysis by nanoscopic metal structures, ranging from nanoparticles to sub-nm clusters and even individual atoms, is amongst the most intensely studied topics in nanoscience. The catalytic performance of supported metal nanoparticles is governed by their crysallographic structure, shape, size, composition and interaction with the support. Aberration-corrected scanning transmission electron microscopy (AC-STEM), with its ultra-high spatial resolution for imaging and compositional analysis, is an ideal tool for characterizing such features in metallic nanocatalysts. In this thesis, five case studies are presented where AC-STEM has been invaluable in elucidating synthesis route - structure - performance relationships in some technologically important catalyst systems.


Computational Study Of Free Jets Emanating From Circular And Lobed Orifice-Lattice Boltzmann Method, Yang Chen Aug 2018

Computational Study Of Free Jets Emanating From Circular And Lobed Orifice-Lattice Boltzmann Method, Yang Chen

Theses and Dissertations

The Lattice Boltzmann method is an effective computational fluid dynamics tool to study complex flows. Unlike conventional numerical schemes based on discretization of macroscopic continuum equations, the Lattice Boltzmann method is based on particles and mesoscopic kinetic equations. Single-Relaxation Time Lattice Boltzmann Method (SRTLBM) with Smagorinsky LES model is applied to simulate high Reynolds number jet flows of single and multiphase flows emanating. The multi-block approach is implemented to refine the mesh when the high resolution is needed in the region around the core jet. An 2nd order accurate interface treatment between neighboring blocks is derived to satisfy the conservation ...


Large Eddy Simulations Of Ventilated Micro-Hydrokinetic Turbine And Pump-Turbines, Cosan Daskiran Aug 2018

Large Eddy Simulations Of Ventilated Micro-Hydrokinetic Turbine And Pump-Turbines, Cosan Daskiran

Theses and Dissertations

Large eddy simulations of ventilated hydrokinetic turbine and pump-turbine are conducted. The mathematical modeling of oxygen dissolution and the flow model employed were validated by comparing predicted dissolved oxygen concentration against reported experimental measurements. A parametric study is performed to investigate the influence of interfacial forces, surface tension and bubble breakage and coalescence terms. It is demonstrated that aeration via hydrokinetic turbines can be used to improve the dissolved oxygen level in rivers for better water quality. It is also shown that aeration can effectively be achieved via the pump-turbine system to provide the desired dissolved oxygen level for the ...