About
52
Publications
19,133
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
856
Citations
Introduction
Skills and Expertise
Publications
Publications (52)
This report summarizes aspects of soiling from different perspectives including particle types and global distributions (Chapter 1), mechanisms and contributing factors (Chapter 2), sensors and measurement techniques (Chapter 3), modelling approaches and results (Chapter 4), economic impacts (Chapter 5), mitigation strategies (Chapter 6), and speci...
Food, energy, and water (FEW) security require adequate quantities and forms of each resource, conditions that are threatened by climate change and other factors. Assessing FEW security is important, and needs to be understood in the context of multiple factors. Existing frameworks make it hard to disentangle the contributors to FEW insecurity and...
Many Alaska communities rely on heating oil for heat and diesel fuel for electricity. For remote communities, fuel must be barged or flown in, leading to high costs. While renewable energy resources may be available, the variability of wind and solar energy limits the amount that can be used coincidentally without adequate storage. This study devel...
Food, energy, and water (FEW) are basic needs for well-being and quality of life. Assessing FEW security allows residents, communities, and policy makers to make informed decisions about how to sustain and improve well-being. We have developed a FEW security assessment framework that examines four components of security: availability, access, quali...
Large‐scale accrual of snow and ice on solar arrays in northern latitudes can cause significant power generation losses during winter. Depending on environmental conditions, snow can encompass a wide range in physical characteristics from dry snow (modulus ≈100 kPa and density ≈0.1 g cm⁻³) to bulk ice (modulus ≈8 GPa and density ≈0.9 g cm⁻³). This...
Food, energy, and water (FEW) are essential for human health and economic development. FEW systems are inextricably interlinked, yet individualized and variable. Consequently, an accurate assessment must include all available and proposed FEW components and their interconnections and consider scale, location, and scope. Remote Alaska locations are...
The food–energy–water (FEW) nexus describes interactions among domains that yield gains or trade-offs when analysed together rather than independently. In a project about renewable energy in rural Alaska communities, we applied this concept to examine the implications for sustainability and resilience. The FEW nexus provided a useful framework for...
With the increasing effects of climate change and high costs of energy, many rural Alaska communities are working to implement local alternative energy solutions to improve energy security. Integrating renewable energy systems can reduce reliance on fossil fuels and subsequently improve food, energy, and water (FEW) security. In this study, wind en...
The food-energy-water (FEW) nexus describes interactions among domains that yield gains or tradeoffs when analyzed together rather than independently. In a project about renewable energy in rural Alaska communities, we applied this concept to examine the implications for sustainability and resilience. The FEW nexus provided a useful framework for i...
This paper presents the first systematic comparison between south-facing monofacial and bifacial photovoltaic (PV) modules, as well as between south-facing bifacial and vertical east-west facing bifacial PV modules in Alaska. The state’s solar industry, driven by the high price of energy and dropping equipment costs, is quickly growing. The challen...
Rural Alaska, home to 229 Alaska Native tribes, is one of the coldest and most isolated regions in the U.S. As a result, it uses more energy than any other state and residents pay some of the highest energy costs per kWh. Water utilities rely heavily on electricity and heating oil to provide reliable service through the cold winter months. Stored w...
High transportation costs make energy and food expensive in remote communities worldwide, especially in high-latitude Arctic climates. Past attempts to grow food indoors in these remote areas have proven uneconomical due to the need for expensive imported diesel for heating and electricity. This study aims to determine whether solar photovoltaic (P...
This paper presents a comparison between bifacial east-west vertical (EWV) and conventional south facing monofacial PV system in Nordic conditions. Special attention is given to the self-consumption rate reached at each system when residential loads are considered. Two test systems with bifacial EWV solar modules were installed, one on the rooftop...
In recent years, there has been increased recognition of the importance of a nexus approach to optimize food, energy, and water (FEW) security at regional and global scales. Remote communities in the Arctic and Subarctic regions in Alaska provide unique examples of closed and isolated systems, wherein the FEW nexus not only needs to be examined to...
In recent years, there has been increased recognition of the importance of a nexus approach to optimize food, energy, and water (FEW) security at regional and global scales. Remote communities in the Arctic and Subarctic regions in Alaska provide unique examples of closed and isolated systems, wherein the FEW nexus not only needs to be examined to...
Diesel generators are the main source of electrical generation in remote Alaska communities; they also help to maintain grid frequency and voltage. In an analysis of key performance metrics for diesel generators in Alaska, we found that the size of the installed system directly affects capital costs, that is, larger systems are more cost-effective...
Electrical transmission lines in Alaska vary from overhead to submarine to underground installations. Analysis indicates that overhead transmission lines are the least expensive to build, ranging from $100 000 to $400 000/mile. Cost variability is influenced by pole spacing, pole heights, line ratings, river crossings, and the amount of work on ene...
In the analysis of energy storage systems (ESSs) in Alaska, the most significant trend in the data considered is the increased variance in costs with time. Thus, more options are now available for ESS with “low cost per kW/high cost per kW h” and vice versa, indicating a greater variety of specialized ESS for targeted applications. The data analyze...
Adding renewable energy to a grid, especially high penetration in a remote microgrid, requires grid integration to maintain stability and maximize the economic benefit of the new energy source. This analysis of integration technologies in Alaska shows a statistically significant increase of around $27/kW in the total integration cost per percent in...
Heat pumps are a proven technology around the world and are being increasingly used in Alaska. Technological advances have improved their performance at low temperatures, making them more suitable for arctic environments. This analysis identified data related to 17 heat pumps installed in Alaska, which included air source, ground source, and sea wa...
This review examines commercial biomass boilers installed around the state of Alaska for key performance and cost metrics. Capital costs and operation and maintenance costs vary with the boiler type and location around the state. Most boiler manufacturers claim system life expectancies of 20–30 years, assuming normal running conditions and adherenc...
Organic Rankine cycle (ORC) technology is mature for larger-scale power generation, but ORC systems appropriate for smaller-capacity generators, typical of Alaska village and other Arctic community power plants, are still new to the market or in the prototype phase. Many villages are being approached by product developers to invest in this new tech...
Solar photovoltaic (PV) technology is a nascent but promising energy option in remote Alaskan microgrids and serves as an example for isolated electrical grids worldwide. This study examines community scale solar PV installations in Alaska, ranging in size from 2.2 kW in Ambler to 50 kW in Galena. Total installed costs arguably show a trend toward...
Many communities in Alaska, especially along the coast, have excellent wind resources and serve as ideal laboratories for microgrids around the Arctic and the world. Wind power systems have been installed in a number of locations in Alaska, both in remote areas and along the road system. As more isolated microgrids are developed worldwide, understa...
Silicon covers more than 90% of photovoltaic cell production and is the
2^nd most Earth-abundant element. In a Bulk Silicon solar cell about
half of the total absorbed energy is lost as heat, following the
detailed balance Shockley-Queisser (SQ) analysis. Generating multiple
excitons (MEG) in quantum confined Nanocrystals per absorbed high energy
p...
Experimental wet chemical approaches to complex an iron atom with two C60 fullerenes, representing a new molecule, dubbed a 'bucky dumbbell', have been demonstrated. The structure of this molecule has been determined by 13C solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). Furthermore, this structure has been s...
Experimental wet chemical approaches have been demonstrated in the synthesis of a new chainlike (C60-Fe-C60-Fe)n complex. This structure has been proposed based on 13C solid-state nuclear magnetic resonance, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Furthermore, this structure has been...
Crystalline WO 3 nanoparticles are employed in the development of flexible electrochromic (EC) devices. The nanoparticles are synthesized at high-density with a hot-wire chemical vapor deposition process where the hot filament provides the source of the tungsten metal. Polyethylene terephthalate coated with indium tin oxide is employed as a transpa...
A study was conducted to demonstrate the fabrication of anodes from crystalline MoO3 nanoparticles that display both a durable reversible capacity of 630mA h g-1 and durable high rate capability. The nanoparticle anodes show no capacity degradation for 150 cycles between 3.5 to 0.005 V with both charge and discharge at C/2, compared to micrometer-s...
Theoretical studies have predicted that scandium can bind to the twelve five-membered rings in C60. It is then possible to stabilize four dihydrogen ligands (H2) on each Sc atom with a binding energy of ∼30 kJ/mol, ideal for vehicular hydrogen storage. The resulting C60[ScH2(H2)4]12 complex is predicted to be a minimum energy structure with ∼7.0 wt...
The combination of shot-noise-limited direct absorption spectroscopy with long-pathlength slit supersonic discharges has proven a powerful general method for obtaining infrared spectra of jet-cooled radicals at 10-20-fold sub-Doppler resolution. In addition to rovibrational characterization, such spectral resolution also provides a novel infrared w...
To expeditiously develop nanostructured materials with high hydrogen sorption capacities, a novel volumetric measurement apparatus was designed and constructed that is suitable for rapid analysis of the small samples (milligram) typically available in the laboratory. The instrument enables both low temperature (down to ˜12K) volumetric measurements...
One of the biggest challenges facing a future hydrogen economy is that
of onboard vehicular hydrogen storage, for which novel carbon-based
nanostructured materials have emerged as potential candidates. Towards
this end, we present the synthesis and characterization of ``bucky
dumbbell,'' a new organometallic compound comprised of two buckyballs
com...
The combination of shot noise-limited direct absorption spectroscopy with long-path-length slit supersonic discharges has been used to obtain first high-resolution infrared spectra for jet-cooled CH2F radicals in the symmetric (nu1) and antisymmetric (nu5) CH2 stretching modes. Spectral assignment has yielded refined lower- and upper-state rotation...
First high-resolution infrared spectra are presented for jet-cooled CH2 35Cl and CH2 37Cl radicals in the symmetric (nu1) CH2 stretching mode. A detailed spectral assignment yields refined lower and upper state rotational constants, as well as fine structure spin-rotation parameters from least-squares fits to the sub-Doppler line shapes for individ...
This thesis describes a series of projects whose common theme comprises the structure and internal energy distribution of gas-phase radicals. In the first two projects, shot noise-limited direct absorption spectroscopy is combined with long path-length slit supersonic discharges to obtain first high-resolution infrared spectra for jet-cooled CH2F a...
Fundamental IR transition strengths arise from vibrationally induced non-zero dipole moment derivatives along a specific normal mode coordinate. A conventional picture of what leads to strong vs. weak intensities in these fundamental vibrations is the bond dipole model, in essence arising from vibrational displacements of partially charged atoms. A...
State-to-state scattering dynamics of F+C2H6-->HF(v,J)+C2H5 have been investigated at Ecom=3.2(6) kcalmol under single-collision conditions, via detection of nascent rovibrationally resolved HF(v,J) product states with high-resolution infrared laser absorption methods. State-resolved Doppler absorption profiles are recorded for multiple HF(v,J) tra...
The retention or inversion of substituted cyclopropyl radical has been a very interesting issue for decades. Recently, the high-resolution infrared spectra of jet-cooled cyclopropyl radical in the in-phase antisymmetric $CH_{2}$ stretching region have been obtained in our slit jet discharge spectrometer. Two vibrational bands have been assigned to...
The $CH_{2}F$ radical is an intermediate in the decomposition of various atmospheric species and is also important in free radical addition reactions. Previous work on the $CH_{2}F$ radical has utilized microwave spectroscopy to determine rotational transitions within the ground vibrational state (the symmetric C-H $stretch)^{a}$. Infrared spectros...
The possibilities of the ring-opening of the cyclopropyl radical to allyl radical and the ring-closure of allyl radical to cyclopropyl radical have been a long-standing question in both experimental and theoretical studies. With a barrier of 22.5kcal/mol, it has been predicted that the ring-opening is topologically disrotatory and hence forbidden,...
This paper focuses on the uptake of SO2 on soot at temperatures below room temperature. Oxidation on soot may provide a mechanism for the oxidation of atmospheric SO2 under conditions when the standard gas-phase and aqueous-phase mechanisms cannot explain the rapid rate of H2SO4 production. An understanding of the uptake of SO2 under dry conditions...
The crystal structure of the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) has been determined by single-crystal X-ray crystallography. Crystals grown by evaporation of an aqueous solution form in the monoclinic space group P2(1)/n with two molecules of PhIP per asymmetric unit, along with six water molecules. The phenyl grou...