Maha N Haji

• PhD
• Assistant Professor at Cornell University

Ideal head height for pumped hydro energy storage/generation systems and reverse osmosis desalination plants coincide (500–700 m). Many drought stricken coastal regions have nearby mountains of sufficient elevation to support upper reservoirs at this ideal head height. A good symbiotic match might thus be realized by co-locating a pumped hydro plan...

As energy usage across the world continues to rise, there is a strong need to develop new methods for energy conservation and power generation, particularly approaches that have less environmental impacts. Although human power is not ideal in terms of life cycle costs [1], there are promising application areas for human power in emerging regions wh...

Accurately predicting wave-structure interactions is critical for the effective design and analysis of marine structures. This is typically achieved using solvers that employ the boundary element method (BEM), which relies on linear potential flow theory. Precise estimation of the sensitivity of these interactions is equally important for system-le...

As emerging marine technologies lead to the development of new infrastructure across the ocean, they enter an environment that existing ecosystems and industries already rely on. Although necessary to provide sustainable sources of energy and food, careful planning will be important to make informed decisions and avoid conflicts. This paper examine...

Wave energy converter farms have the potential to reduce wave-induced fatigue loads on offshore wind turbines, reducing material, production, transportation, and installation costs. Wave energy converters (WECs) dampen incoming waves, producing a sheltering effect for downstream bodies. This work compares the sheltering effect of three wave energy...

This study utilizes multidisciplinary design optimization (MDO) to design an array of heaving wave energy converters (WECs) for grid-scale energy production with decision variables and parameters chosen from the coupled disciplines of geometry, hydrodynamics, layout, motor-actuated reactive controls (with a force maximum constraint) and economics....

Actuator saturation is a common nonlinearity. In wave energy conversion, force saturation conveniently limits drivetrain size and cost with minimal impact on energy generation. However, such nonlinear dynamics typically demand numerical simulation, which increases computational cost and diminishes intuition. This paper instead uses describing funct...

A design optimization framework for an active orbital debris removal mission to minimize the life cycle cost and mission time is presented. The general concept of operations consists of spacecraft capable of deorbiting 22 identical high-priority debris from sun-synchronous orbit via continuous low thrust from electrostatic thrusters. This modular s...

Lithium, the lightest alkali metal, has been called the “new white gold” because of its limited availability and critical importance in arising applications in clean energy, like hybrid and electric vehicles. However, the rapidly growing demand for lithium, combined with its low global production rates, has led to concerns regarding the development...

Ocean waves have the potential to provide clean energy to large swaths of society. Despite their promise, wave energy converters (WECs) are prohibitively expensive, partly due to the lack of design convergence in the WEC industry. A system-level optimization facilitates cost reduction, systematic evaluation of various architectures, and ultimately...

Wave energy converters (WECs) have the potential to be major players in the renewable energy sphere. WEC arrays are well suited for grid-scale energy, offshore aquaculture, water desalination, coastal communities, and other niche applications. Understanding the effect of an array on the surrounding wave field is crucial to accurate modeling, determ...

With many countries planning to significantly increase grid renewable energy penetration levels, we consider the role of wave energy in supply–demand matching. We investigate how incorporating wave power into an offshore wind farm affects farm power predictability, smoothness, required energy storage capacity, and cost. In this paper, we do a first...

This paper describes the design, implementation, and field‐testing of a low‐cost autonomous control system on the Platform for Expanding Autonomous Underwater Vehicles (AUV) exploRation to Longer ranges (PEARL). PEARL is a floating, solar‐powered platform designed as a servicing station for AUVs. This paper describes the field testing of a prototyp...

Under the Paris Agreement, established by the United Nations Framework Convention on Climate Change, many countries have agreed to transition their energy sources and technologies to reduce greenhouse gas emissions to levels concordant with the 1.5°C warming goal. Lithium (Li) is critical to this transition due to its use in nuclear fusion as well...

Wave energy converters (WECs) can advance the global energy transition by producing clean power for utility grids and offshore technologies. This paper provides a multidisciplinary, dual objective optimization of the Reference Model 3 (RM3), a two-body point absorber WEC design benchmark. The simulation model employs linear hydrodynamics with force...

This paper describes the design, fabrication, and field testing plans of a 1:2 Froude-scale prototype of a Platform for Expanding AUV exploRation to Longer ranges (PEARL). PEARL is an autonomous floating platform that utilizes renewable energy to recharge docked AUVs, while simultaneously uploading their mission data to a high-bandwidth low-Earth o...

Many regions, such as coastal communities, are often located at the end of large transmission lines, leaving them susceptible to power outages and reliant on conventional fuels. We propose a multi-disciplinary, multi-objective optimization method to design a hybrid renewable energy system mix including solar, wind, and marine energy. The method fir...

Autonomous Underwater Vehicle (AUV) missions are limited in range and duration by the vehicle’s battery capacity, and sensor payloads are limited by the processing power onboard which is also restricted by the vehicle’s battery capacity. Furthermore, the power consumption of a vehicle’s acoustic system limits the possibility of substantial data tra...

2020 American Society of Mechanical Engineers (ASME). All rights reserved. Autonomous Underwater Vehicle (AUV) missions are limited in range and duration by the vehicle's battery capacity, and sensor payloads are limited by the processing power onboard which is also restricted by the vehicle's battery capacity. Furthermore, the power consumption of...

The predicted dominance of electric vehicles and the need for grid-scale energy storage have heightened concerns that cobalt, a key constituent of lithium-ion batteries, could become a critical limiting factor. With limited terrestrial resources and over half the global production coming from politically challenging regions increasing risk, a short...

Amidoxime-based adsorbents have become highly promising for seawater uranium extraction. However, current deployment schemes are stand-alone, intermittent operation systems that have significant practical and economic challenges. This paper presents two 1/10th scale prototypes of a Symbiotic Machine for Ocean uRanium Extraction (SMORE) which pairs...

The recovery of uranium from seawater has the potential to transform the perceived sustainability of energy generated by uranium intensive nuclear fuel cycles, while providing environmental benefits as compared to land-based mining. Combining a seawater uranium harvester with an existing offshore wind turbine allows for denser energy recovery per u...

The capital cost of a 5 MW floating wind turbine (FWT) runs as high as $20.7 million, leading to an energy cost of $0.20/kWh, four times that of natural gas (Myhr et al., 2014). Although a single type of energy harvesting device may be too expensive to deploy, if it can operate symbiotically with others, the combined cost of energy might be accepta...

This study aims to evaluate the impact of shell enclosures on the uranium uptake of amidoxime-based polymeric adsorbents they contain. Researchers have observed that the tensile strength of the adsorbent's polyethylene backbone is degraded after γ-irradiation to induce grafting of the amidoxime ligand. A two-part system was developed to decouple th...

With conventional sources of uranium forecasted to be depleted within a century, developing methods to cost-effectively harvest uranium from seawater, which is estimated to contain 1,000 times more uranium than land does, is crucial to the continued viability of nuclear power generation. Studies have shown that coupling a uranium harvester system w...

Seawater is estimated to contain 4.5 billion tonnes of uranium, approximately 1000 times that available in conventional terrestrial resources. Finding a sustainable way to harvest uranium from seawater will provide a source of nuclear fuel for generations to come, while also giving all countries with ocean access a stable supply. This will also eli...

The scattering of low-mode internal tides by ocean-floor topography is extensively studied through analytical models and field observations at the Line Islands Ridge (LIR). An existing Green function method is utilized to examine the generation of internal tides by idealized topographic shapes as well as realistic transects of the LIR. The method i...

Tides are one of the main sources of energy input to the deep ocean, and the pathways of energy transfer from barotropic tides to turbulent mixing scales via internal tides are not well understood. Large-scale (low-mode) internal tides account for the bulk of energy extracted from barotropic tides and have been observed to propagate over 1000 km fr...

Drag forces on bluff bodies are directly proportional to the wake region downstream of the body, which is governed by the boundary layer separation point. These drag forces can be significantly reduced by delaying vortex separation and thereby decreasing a body’s wake region. This project examines the effectiveness of a method of boundary layer man...

As energy usage across the world continues to rise, there is a strong need to develop new methods for energy conservation and power generation, particularly approaches that have less environmental impacts. Although human power is not ideal in terms of life cycle costs [1], there are promising application areas for human power in emerging regions wh...