Adam Boies

All Publications

• Vehicle emission models alone are not sufficient to understand full impact of change in traffic signal timings ATMOSPHERIC ENVIRONMENT-X Schroeder, A. K., Woodward, H., Le Cornec, C. A., Proust, T., Benie, P. J., Fan, S., Aristodemou, E., Jones, R. L., Linden, P. F., de Nazelle, A., Boies, A. M., Stettler, M. J. 2024; 24

  View details for DOI 10.1016/j.aeaoa.2024.100293

  View details for Web of Science ID 001336212900001

• Airborne Tire Wear Particles: A Critical Reanalysis of the Literature Reveals Emission Factors Lower than Expected ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Saladin, S., Boies, A., Giorio, C. 2024

  View details for DOI 10.1021/acs.estlett.4c00792

  View details for Web of Science ID 001363906500001

• Gas-Phase Dynamics of Bundle Formation from High-Aspect-Ratio Carbon Nanotubes. Langmuir : the ACS journal of surfaces and colloids Qiao, R., Qiu, X., Boies, A. 2024

  Abstract

  In floating catalyst chemical vapor deposition (FCCVD), high-aspect-ratio carbon nanotubes (CNTs) are produced in the gas phase at high number concentrations and undergo collision and agglomeration, eventually giving rise to a macroscale aerogel, enabling functional material forms such as fibers or mats to be obtained directly from the synthesis process. The self-assembly behavior between high-aspect-ratio CNTs dictates the resulting morphology at the nanoscale and subsequently the bulk properties of the CNT product. Reorientation between CNTs after collision is a critical step that results in bundle formation and precedes aerogel formation. However, it has been challenging to study the phenomenon with existing methods as it spans multiple time and length scales. In this study, a physics-based semi-analytical model was developed to study the gas-phase reorientation dynamics of high-aspect-ratio CNTs and their bundles, with ±10% accuracy compared with mesoscale molecular dynamics simulations, but at <0.1% the computational cost. It was revealed that the reorientation time scale is dictated by the interplay among the van der Waals potential, drag, and the geometric configuration of CNTs upon collision. This then allows the time scale of reorientation (i.e., bundle formation) to be compared with other gas-phase dynamics in a typical FCCVD reactor and offers new insights into the self-assembly behavior of 1D nanoparticles in the gas phase.

  View details for DOI 10.1021/acs.langmuir.4c02260

  View details for PubMedID 39348526

• Method development and analysis of nanoparticle size fractions from tire-wear emissions ENVIRONMENTAL SCIENCE-ATMOSPHERES Haugen, M., Buehler, P., Schlaefle, S., O'Loughlin, D., Saladin, S., Giorio, C., Boies, A. 2024; 4 (9): 1079-1090

  View details for DOI 10.1039/d4ea00048j

  View details for Web of Science ID 001294256600001

• Charge-Based Separation of Microparticles Using AC Insulator-Based Dielectrophoresis ANALYTICAL CHEMISTRY Tabarhoseini, S., Kale, A., Koniers, P., Boone, A., Bentor, J., Boies, A., Zhao, H., Xuan, X. 2024; 96 (33): 13672-13678

  Abstract

  Surface charge is an important property of particles. It has been utilized to separate particles in microfluidic devices, where dielectrophoresis (DEP) is often the driving force. However, current DEP-based particle separations based on the charge differences work only for particles of similar sizes. They become less effective and may even fail for a mixture of particles differing in both charge and size. We demonstrate that our recently developed AC insulator-based dielectrophoresis (AC iDEP) technique can direct microparticles toward charge-dependent equilibrium positions in a ratchet microchannel. Such charge-based particle separation is controlled by the imposed AC voltage frequency and amplitude but is nearly unaffected by the size of either type of particle in the mixture except for the time required to achieve an effective separation. This AC iDEP technique may potentially be used to focus and separate submicron or even nanoparticles because of its virtually "infinite" channel length.

  View details for DOI 10.1021/acs.analchem.4c02646

  View details for Web of Science ID 001290007700001

  View details for PubMedID 39126704

• Synthesis Pathway of Layered-Oxide Cathode Materials for Lithium-Ion Batteries by Spray Pyrolysis ACS APPLIED MATERIALS & INTERFACES Almazrouei, M., Park, S., Houck, M., De Volder, M., Hochgreb, S., Boies, A. 2024; 16 (26): 33633-33646

  Abstract

  We report the synthesis of LiCoO2 (LCO) cathode materials for lithium-ion batteries via aerosol spray pyrolysis, focusing on the effect of synthesis temperatures from 600 to 1000 °C on the materials' structural and morphological features. Utilizing both nitrate and acetate metal precursors, we conducted a comprehensive analysis of material properties through X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Our findings reveal enhanced crystallinity and significant oxide decomposition within the examined temperature range. Morphologically, nitrate-derived particles exhibited hollow, spherical shapes, whereas acetate-derived particles were irregular. Guided by high-temperature X-ray diffraction (HT-XRD) data, the formation of a layered LCO oxide structure, with distinct spinel Li2Co2O4 and layered oxide LCO phases was shown to emerge at different annealing temperatures. Optimally annealed particles showcased well-defined layered structures, translating to high electrochemical performance. Specifically, nitrate-based particles annealed at 775 °C for 1 h demonstrated initial discharge capacities close to 179 mAh/g, while acetate-based particles, annealed at 750 °C for 3 h, achieved 136 mAh/g at a 0.1C discharge rate. This study elucidates the influence of synthesis conditions on LCO cathode material properties, offering insights that advance high throughput processes for lithium-ion battery materials synthesis.

  View details for DOI 10.1021/acsami.4c06503

  View details for Web of Science ID 001253350800001

  View details for PubMedID 38910450

  View details for PubMedCentralID PMC11231976

• Exploring the bounds of methane catalysis in the context of atmospheric methane removal ENVIRONMENTAL RESEARCH LETTERS Tsopelakou, A., Stallard, J., Archibald, A. T., Fitzgerald, S., Boies, A. M. 2024; 19 (5)

  View details for DOI 10.1088/1748-9326/ad383f

  View details for Web of Science ID 001203284600001

• Flexible Bifunctional Electrode for Alkaline Water Splitting with Long-Term Stability ACS APPLIED MATERIALS & INTERFACES Ganguly, A., Mcglynn, R. J., Boies, A., Maguire, P., Mariotti, D., Chakrabarti, S. 2024; 16 (10): 12339-12352

  Abstract

  Progress in electrochemical water-splitting devices as future renewable and clean energy systems requires the development of electrodes composed of efficient and earth-abundant bifunctional electrocatalysts. This study reveals a novel flexible and bifunctional electrode (NiO@CNTR) by hybridizing macroscopically assembled carbon nanotube ribbons (CNTRs) and atmospheric plasma-synthesized NiO quantum dots (QDs) with varied loadings to demonstrate bifunctional electrocatalytic activity for stable and efficient overall water-splitting (OWS) applications. Comparative studies on the effect of different electrolytes, e.g., acid and alkaline, reveal a strong preference for alkaline electrolytes for the developed NiO@CNTR electrode, suggesting its bifunctionality for both HER and OER activities. Our proposed NiO@CNTR electrode demonstrates significantly enhanced overall catalytic performance in a two-electrode alkaline electrolyzer cell configuration by assembling the same electrode materials as both the anode and the cathode, with a remarkable long-standing stability retaining ∼100% of the initial current after a 100 h long OWS run, which is attributed to the "synergistic coupling" between NiO QD catalysts and the CNTR matrix. Interestingly, the developed electrode exhibits a cell potential (E10) of only 1.81 V with significantly low NiO QD loading (83 μg/cm2) compared to other catalyst loading values reported in the literature. This study demonstrates a potential class of carbon-based electrodes with single-metal-based bifunctional catalysts that opens up a cost-effective and large-scale pathway for further development of catalysts and their loading engineering suitable for alkaline-based OWS applications and green hydrogen generation.

  View details for DOI 10.1021/acsami.3c12944

  View details for Web of Science ID 001180086300001

  View details for PubMedID 38425008

  View details for PubMedCentralID PMC10941191

• Continuous gas-phase synthesis of iron nanoparticles at ambient conditions with controllable size and polydispersity JOURNAL OF COLLOID AND INTERFACE SCIENCE Qiao, R., Boies, A. 2024; 658: 986-996

  Abstract

  By altering aerosol growth dynamics with unipolar charges, one can obtain aerosols with narrow particles size distributions, a highly desirable feature in applications of functional nanoparticles.Unlike liquid colloid systems, aerosol particles in the free molecular regime undergo coarsening due to Brownian coagulation and will eventually attain a self-preserving size distribution with a typical geometric standard deviation of 1.46 - 1.48. We developed a novel continuous one-step aerosol synthesis reactor that produces iron nanoparticles from ferrocene at ambient conditions, which confines the site of precursor breakdown and particle formation in the downstream vicinity of a positive corona discharge.We demonstrated that the particle size could be controlled within 3 - 10 nm with a suppressed geometric standard deviation (1.15 - 1.35). The as-produced iron nanoparticles were successfully used as catalyst for the growth of single-walled carbon nanotubes with a narrow diameter range. With a transient aerosol dynamics model, we showed that a fraction (as small as 0.1%) of unipolar-charged particles could have a significant impact on the aerosol growth dynamics, which eventually results in a narrower particle size distribution with smaller size and higher number concentrations.

  View details for DOI 10.1016/j.jcis.2023.11.097

  View details for Web of Science ID 001165870600001

  View details for PubMedID 38159359

• Dynamics of unipolar charged particles flowing through a cylindrical tube at high number concentrations JOURNAL OF AEROSOL SCIENCE Kale, A., Woo, M., Swanson, J. J., Lim, D., Boies, A. M. 2024; 176

  View details for DOI 10.1016/j.jaerosci.2023.106310

  View details for Web of Science ID 001161625400001

• Enhanced composite thermal conductivity by percolated networks of <i>in</i>-<i>situ</i> confined-grown carbon nanotubes NANO RESEARCH Zhang, X., Tan, W., Carey, T., Wen, B., He, D., Arbab, A., Groombridge, A., Smail, F., de La Verpilliere, J., Yao, C., Wang, Y., Wei, X., Liu, H., Xie, S., Torrisi, F., De Volder, M., Zhou, W., Boies, A. 2023

  View details for DOI 10.1007/s12274-023-6209-6

  View details for Web of Science ID 001103109300001

• Enhanced Visible Light-Driven Photocatalytic Water-Splitting Reaction of Titanate Nanotubes Sensitised with Ru(II) Bipyridyl Complex NANOMATERIALS Malizia, M., Scott, S. A., Torrente-Murciano, L., Boies, A. M., Aljohani, T. A., Baldovi, H. G. 2023; 13 (22)

  Abstract

  The ion exchange of Na+ cations was used to photosensitise titanates nanotubes (Ti-NTs) with tris(2,2'-bipyridine)ruthenium(II) cations (Ru(bpy)32+); this yielded a light-sensitised Ti-NTs composite denoted as (Ru(bpy)3)Ti-NTs, exhibiting the characteristic absorption of Ru(bpy)32+ in visible light. Incident photon-to-current efficiency (IPCE) measurements and the photocatalytic reduction of methyl viologen reaction confirmed that in the photosensitisation of the (Ru(bpy)3)Ti-NTs composite, charge transfer and charge separation occur upon excitation by ultraviolet and visible light irradiation. The photocatalytic potential of titanate nanotubes was tested in the water-splitting reaction and the H2 evolution reaction using a sacrificial agent and showed photocatalytic activity under various light sources, including xenon-mercury lamp, simulated sunlight, and visible light. Notably, in the conditions of the H2 evolution reaction when (Ru(bpy)3)Ti-NTs were submitted to simulated sunlight, they exceeded the photocatalytic activity of pristine Ti-NTs and TiO2 by a factor of 3 and 3.5 times, respectively. Also, (Ru(bpy)3)Ti-NTs achieved the photocatalytic water-splitting reaction under simulated sunlight and visible light, producing, after 4 h, 199 and 282 μmol×H2×gcat-1. These results confirm the effective electron transfer of Ru(bpy)3 to titanate nanotubes. The stability of the photocatalyst was evaluated by a reuse test of four cycles of 24 h reactions without considerable loss of catalytic activity and crystallinity.

  View details for DOI 10.3390/nano13222959

  View details for Web of Science ID 001122524800001

  View details for PubMedID 37999313

  View details for PubMedCentralID PMC10674862

• Condensation particle counters: Exploring the limits of miniaturisation JOURNAL OF AEROSOL SCIENCE Balendra, S., Kale, A., Pongetti, J., Kazemimanesh, M., Haugen, M., Weller, L., Boies, A. 2024; 175

  View details for DOI 10.1016/j.jaerosci.2023.106266

  View details for Web of Science ID 001082245000001

• Boosting total oxidation of methane over NiO nanocrystalline decorated ZnO-CoNi solid solution via photothermal synergism APPLIED CATALYSIS B-ENVIRONMENTAL Sun, C., Zhao, K., Boies, A., Xiao, S., Yi, Z. 2023; 339

  View details for DOI 10.1016/j.apcatb.2023.123124

  View details for Web of Science ID 001059860500001

• Overview of methods to characterize the mass, size, and morphology of soot JOURNAL OF AEROSOL SCIENCE Sipkens, T. A., Boies, A., Corbin, J. C., Chakrabarty, R. K., Olfert, J., Rogak, S. N. 2023; 173

  View details for DOI 10.1016/j.jaerosci.2023.106211

  View details for Web of Science ID 001118637800001

• Multi-element analysis of tyre rubber for metal tracers ENVIRONMENT INTERNATIONAL O'Loughlin, D. P., Haugen, M. J., Day, J., Brown, A. S., Braysher, E. C., Molden, N., Willis, A. E., MacFarlane, M., Boies, A. M. 2023; 178: 108047

  Abstract

  The purpose of this study was to identify a characteristic elemental tyre fingerprint that can be utilised in atmospheric source apportionment calculations. Currently zinc is widely used as a single element tracer to quantify tyre wear, however several authors have highlighted issues with this approach. To overcome this, tyre rubber tread was digested and has been analysed for 25 elements by ICP-MS to generate a multielement profile. Additionally, to estimate the percentage of the tyre made up of inert fillers, thermogravimetric analysis was performed on a subset. Comparisons were made between passenger car and heavy goods vehicle tyre composition, and a subset of tyres had both tread and sidewall sampled for further comparison. 19 of the 25 elements were detected in the analysis. The mean mass fraction of zinc detected was 11.17 g/kg, consistent with previous estimates of 1% of the tyre mass. Aluminium, iron, and magnesium were found to be the next most abundant elements. Only one source profile for tyre wear exists in both the US and EU air pollution species profile databases, highlighting the need for more recent data with better coverage of tyre makes and models. This study provides data on new tyres which are currently operating on-road in Europe and is therefore relevant for ongoing atmospheric studies assessing the levels of tyre wear particles in urban areas.

  View details for DOI 10.1016/j.envint.2023.108047

  View details for Web of Science ID 001039601400001

  View details for PubMedID 37419058

• Parameterization and modeling protocols for ultra-fast charging Wadsley-Roth lithium-ion batteries from coin to pouch cells CELL REPORTS PHYSICAL SCIENCE Houck, M. E., Groombridge, A. S., De Volder, M. L., Boies, A. M. 2023; 4 (5)

  View details for DOI 10.1016/j.xcrp.2023.101410

  View details for Web of Science ID 001030335300001

• Compact aerosol aggregate model (CA<SUP>2</SUP>M): A fast tool to estimate the aerosol properties of fractal-like aggregates AEROSOL SCIENCE AND TECHNOLOGY Jourdain, C., Symonds, J. R., Boies, A. M. 2023; 57 (8): 797-809

  View details for DOI 10.1080/02786826.2023.2206442

  View details for Web of Science ID 000983658800001

• Analysis of Differences in Electrochemical Performance Between Coin and Pouch Cells for Lithium-Ion Battery Applications ENERGY & ENVIRONMENTAL MATERIALS Son, Y., Cha, H., Lee, T., Kim, Y., Boies, A., Cho, J., De Volder, M. 2024; 7 (3)

  View details for DOI 10.1002/eem2.12615

  View details for Web of Science ID 000964885700001

• Direct-spun CNT textiles for high-performance electromagnetic interference shielding in an ultra-wide bandwidth CARBON Issman, L., Alper, M., Howard, S., Karch, C., Yeshurun, S., Pick, M., Boies, A. 2023; 206: 166-180

  View details for DOI 10.1016/j.carbon.2023.02.013

  View details for Web of Science ID 000943119900001

• Simultaneously enhanced tenacity, rupture work, and thermal conductivity of carbon nanotube fibers by raising effective tube portion SCIENCE ADVANCES Zhang, X., De Volder, M., Zhou, W., Issman, L., Wei, X., Kaniyoor, A., Portas, J., Smail, F., Wang, Z., Wang, Y., Liu, H., Zhou, W., Elliott, J., Xie, S., Boies, A. 2022; 8 (50): eabq3515

  Abstract

  Although individual carbon nanotubes (CNTs) are superior to polymer chains, the mechanical and thermal properties of CNT fibers (CNTFs) remain inferior to synthetic fibers because of the failure of embedding CNTs effectively in superstructures. Conventional techniques resulted in a mild improvement of target properties while degrading others. Here, a double-drawing technique is developed to rearrange the constituent CNTs. Consequently, the mechanical and thermal properties of the resulting CNTFs can simultaneously reach their highest performances with specific strength ~3.30 N tex-1 (4.60 GPa), work of rupture ~70 J g-1, and thermal conductivity ~354 W m-1 K-1 despite starting from low-crystallinity materials (IG:ID ~ 5). The processed CNTFs are more versatile than comparable carbon fiber, Zylon and Dyneema. On the basis of evidence of load transfer efficiency on individual CNTs measured with in situ stretching Raman, we find that the main contributors to property enhancements are the increasing of the effective tube contribution.

  View details for DOI 10.1126/sciadv.abq3515

  View details for Web of Science ID 000905194200024

  View details for PubMedID 36516257

  View details for PubMedCentralID PMC9750159

• Measuring the Air Quality Using Low-Cost Air Sensors in a Parking Garage at University of Minnesota, USA INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH Gonzalez, A., Boies, A., Swanson, J., Kittelson, D. 2022; 19 (22)

  Abstract

  The concentration of air pollutants in underground parking garages has been found to be higher compared to ambient air. Vehicle emissions from cold starts are the main sources of air pollution in underground parking garages. Eight days of measurements, using low-cost air sensors, were conducted at one underground parking garage at the University of Minnesota, Minneapolis. The CO, NO, NO2, and PM2.5 daily average concentrations in the parking garage were measured to be higher, by up to more than an order of magnitude, compared to the ambient concentration. There is positive correlation between exit traffic flow and the air concentrations in the parking garage for lung deposited surface area (LDSA), CO2, NO, and CO. Fuel specific emission factors were calculated for CO, NO, and NOx. Ranging from 25 to 28 g/kgfuel for CO, from 1.3 to 1.7 g/kgfuel for NO, and from 2.1 to 2.7 g/kgfuel for NOx. Regulated emissions were also calculated for CO and NOx with values of 2.4 to 2.9 and 0.19 to 0.25 g/mile, respectively. These emissions are about 50% higher than the 2017 U.S. emission standards for CO and nearly an order magnitude higher for NOx.

  View details for DOI 10.3390/ijerph192215223

  View details for Web of Science ID 000887508400001

  View details for PubMedID 36429940

  View details for PubMedCentralID PMC9690026

• Forecasting carbon nanotube diameter in floating catalyst chemical vapor deposition CARBON Bulmer, J. S., Sloan, A. N., Glerum, M., Carpena-Nunez, J., Waelder, R., Humes, J., Boies, A. M., Pasquali, M., Rao, R., Maruyama, B. 2023; 201: 719-733

  View details for DOI 10.1016/j.carbon.2022.08.001

  View details for Web of Science ID 000868911500003

• Measurements and modelling of the three-dimensional near-field dispersion of particulate matter emitted from passenger ships in a port environment ATMOSPHERIC ENVIRONMENT Haugen, M. J., Gkantonas, S., El Helou, I., Pathania, R., Mastorakos, E., Boies, A. M. 2022; 290

  View details for DOI 10.1016/j.atmosenv.2022.119384

  View details for Web of Science ID 000862277900001

• Towards Portable MEMS Oscillators for Sensing Nanoparticles SENSORS Chellasivalingam, M., Zielinski, A. T., Whitney, T. S., Boies, A. M., Seshia, A. A. 2022; 22 (15)

  Abstract

  This paper reports on the design, and implementation of piezoelectric-on-silicon MEMS resonators installed within a portable experimental setup for sensing nanoparticles in a laboratory environment. MEMS oscillators with a center frequency of approximately 5.999 MHz are employed for sensing 50 nm size-selected silver nanoparticles generated in the laboratory. The same experimental setup is then assembled to sense indoor particles that are present in the laboratory environment. The challenges associated with particle deposition as a result of assembling the portable experimental setup is highlighted. Furthermore, the MEMS oscillators demonstrate that the total mass of silver nanoparticles deposited onto the MEMS resonator surface using the inertial impaction technique-based experimental setup is approximately 7.993 nanograms. The total indoor particle mass accumulated on the MEMS resonator surface is estimated to be approximately 1.732 nanograms and 26.9 picograms for two different runs. The frequency resolution of the MEMS oscillator is estimated to be approximately 32 ppb and, consequently, the minimum detectable particle mass is approximately 60 femtograms for a 9.2 s integration time.

  View details for DOI 10.3390/s22155485

  View details for Web of Science ID 000839983800001

  View details for PubMedID 35897988

  View details for PubMedCentralID PMC9330167

• High degree of N-functionalization in macroscopically assembled carbon nanotubes JOURNAL OF MATERIALS SCIENCE McGlynn, R. J., Brunet, P., Chakrabarti, S., Boies, A., Maguire, P., Mariotti, D. 2022; 57 (28): 13314-13325

  View details for DOI 10.1007/s10853-022-07463-7

  View details for Web of Science ID 000825912700002

• A study on the performance of low-cost sensors for source apportionment at an urban background site ATMOSPHERIC MEASUREMENT TECHNIQUES Bousiotis, D., Beddows, D. S., Singh, A., Haugen, M., Diez, S., Edwards, P. M., Boies, A., Harrison, R. M., Pope, F. D. 2022; 15 (13): 4047-4061

  View details for DOI 10.5194/amt-15-4047-2022

  View details for Web of Science ID 000821945800001

• Highly Oriented Direct-Spun Carbon Nanotube Textiles Aligned by In Situ Radio-Frequency Fields ACS NANO Issman, L., Kloza, P. A., Portas, J., Collins, B., Pendashteh, A., Pick, M., Vilatela, J. J., Elliott, J. A., Boies, A. 2022; 16 (6): 9583-9597

  Abstract

  Carbon nanotubes (CNTs) individually exhibit exceptional physical properties, surpassing state-of-the-art bulk materials, but are used commercially primarily as additives rather than as a standalone macroscopic product. This limited use of bulk CNT materials results from the inability to harness the superb nanoscale properties of individual CNTs into macroscopic materials. CNT alignment within a textile has been proven as a critical contributor to narrow this gap. Here, we report the development of an altered direct CNT spinning method based on the floating catalyst chemical vapor deposition process, which directly interacts with the self-assembly of the CNT bundles in the gas phase. The setup is designed to apply an AC electric field to continuously align the CNTs in situ during the formation of CNT bundles and subsequent aerogel. A mesoscale CNT model developed to simulate the alignment process has shed light on the need to employ AC rather than DC fields based on a CNT stiffening effect (z-pinch) induced by a Lorentz force. The AC-aligned synthesis enables a means to control CNT bundle diameters, which broadened from 16 to 25 nm. The resulting bulk CNT textiles demonstrated an increase in the specific electrical and tensile properties (up to 90 and 460%, respectively) without modifying the quantity or quality of the CNTs, as verified by thermogravimetric analysis and Raman spectroscopy, respectively. The enhanced properties were correlated to the degree of CNT alignment within the textile as quantified by small-angle X-ray scattering and scanning electron microscopy image analysis. Clear alignment (orientational order parameter = 0.5) was achieved relative to the pristine material (orientational order parameter = 0.19) at applied field intensities in the range of 0.5-1 kV cm-1 at a frequency of 13.56 MHz.

  View details for DOI 10.1021/acsnano.2c02875

  View details for Web of Science ID 000821219000001

  View details for PubMedID 35638849

  View details for PubMedCentralID PMC9245349

• Open-source modelling of aerosol dynamics and computational fluid dynamics: Bipolar and unipolar diffusion charging and photoelectric charging COMPUTER PHYSICS COMMUNICATIONS Woo, M., Schriefl, M. A., Knoll, M., Boies, A. M., Stettler, M. J., Hochgreb, S., Nishida, R. T. 2022; 278

  View details for DOI 10.1016/j.cpc.2022.108399

  View details for Web of Science ID 000831314600004

• Source terms for benchmarking models of SARS-CoV-2 transmission via aerosols and droplets ROYAL SOCIETY OPEN SCIENCE Stettler, M. J., Nishida, R. T., de Oliveira, P. M., Mesquita, L. C., Johnson, T. J., Galea, E. R., Grandison, A., Ewer, J., Carruthers, D., Sykes, D., Kumar, P., Avital, E., Obeysekara, A. B., Doorly, D., Hardalupas, Y., Green, D. C., Coldrick, S., Parker, S., Boies, A. M. 2022; 9 (5): 212022

  Abstract

  There is ongoing and rapid advancement in approaches to modelling the fate of exhaled particles in different environments relevant to disease transmission. It is important that models are verified by comparison with each other using a common set of input parameters to ensure that model differences can be interpreted in terms of model physics rather than unspecified differences in model input parameters. In this paper, we define parameters necessary for such benchmarking of models of airborne particles exhaled by humans and transported in the environment during breathing and speaking.

  View details for DOI 10.1098/rsos.212022

  View details for Web of Science ID 001133682200007

  View details for PubMedID 35592762

  View details for PubMedCentralID PMC9066307

• Differentiating Semi-Volatile and Solid Particle Events Using Low-Cost Lung-Deposited Surface Area and Black Carbon Sensors ATMOSPHERE Haugen, M. J., Singh, A., Bousiotis, D., Pope, F. D., Boies, A. M. 2022; 13 (5)

  View details for DOI 10.3390/atmos13050747

  View details for Web of Science ID 000802520600001

• Measuring the effect of fireworks on air quality in Minneapolis, Minnesota SN APPLIED SCIENCES Gonzalez, A., Boies, A., Swanson, J., Kittelson, D. 2022; 4 (5)

  View details for DOI 10.1007/s42452-022-05023-x

  View details for Web of Science ID 000781118000002

• Electrification versus hydrogen for UK road freight: Conclusions from a systems analysis of transport energy transitions ENERGY FOR SUSTAINABLE DEVELOPMENT Haugen, M. J., Flynn, D., Greening, P., Tichler, J., Blythe, P., Boies, A. M. 2022; 68

  View details for DOI 10.1016/j.esd.2022.03.011

  View details for Web of Science ID 000797077600001

• A comparative study on effective density, shape factor, and volatile mixing of non-spherical particles using tandem aerodynamic diameter, mobility diameter, and mass measurements JOURNAL OF AEROSOL SCIENCE Kazemimanesh, M., Rahman, M., Duca, D., Johnson, T. J., Addad, A., Giannopoulos, G., Focsa, C., Boies, A. M. 2022; 161

  View details for DOI 10.1016/j.jaerosci.2021.105930

  View details for Web of Science ID 000790806300005

• Utah Wintertime Measurements of Heavy-Duty Vehicle Nitrogen Oxide Emission Factors ENVIRONMENTAL SCIENCE & TECHNOLOGY Bishop, G. A., Haugen, M. J., McDonald, B. C., Boies, A. M. 2022; 56 (3): 1885-1893

  Abstract

  There have only been a few wintertime studies of heavy-duty vehicle (HDV) NOx emissions in the United States, and while they have observed increased emissions, fleet characterization to identify the cause has been lacking. We have collected wintertime measurements of NOx emission factors from 1591 HDVs at a Utah Port of Entry in December 2020 that includes individual vehicle identification. In general, NOx emission factors for 2011 and newer chassis model year HDV are significantly higher than those for 2017 spring measurements from California. The newest chassis model year HDV (2017-2021) NOx emission factors are similar, indicating no significant emission deterioration over the 5 year period, though they are still approximately a factor of 3 higher than the portable emission measurement on-road enforcement standard. We estimate that ambient temperature increases NOx emissions no more than 25% in the newer HDV, likely through reductions in catalyst efficiencies. NOx emissions increase to a significantly higher level for the 2011-2013 chassis model year vehicles, where within the uncertainties, they have emissions similar to older precontrol vehicles, indicating that they have lost their NOx control capabilities within 8 years. MOVES3 modeling of the Utah fleet underpredicted mean NOx emissions by a factor of 1.8 but the MOVES3 estimate is helped by including a larger fraction of high-emitting glider kit trucks (new chassis with pre-emission control engines) than found in the observations.

  View details for DOI 10.1021/acs.est.1c06428

  View details for Web of Science ID 000745833300001

  View details for PubMedID 35044770

• Reliable protocols for calculating the specific energy and energy density of Li-Ion batteries MATERIALS TODAY ENERGY Son, Y., Cha, H., Jo, C., Groombridge, A. S., Lee, T., Boies, A., Cho, J., De Volder, M. 2021; 21

  View details for DOI 10.1016/j.mtener.2021.100838

  View details for Web of Science ID 000701845300001

• Filtration of viral aerosols via a hybrid carbon nanotube active filter CARBON Issman, L., Graves, B., Terrones, J., Hosmillo, M., Qiao, R., Glerum, M., Yeshurun, S., Pick, M., Goodfellow, I., Elliott, J., Boies, A. 2021; 183: 232-242

  View details for DOI 10.1016/j.carbon.2021.07.004

  View details for Web of Science ID 000705083800024

• Assessing the sources of particles at an urban background site using both regulatory instruments and low-cost sensors - a comparative study ATMOSPHERIC MEASUREMENT TECHNIQUES Bousiotis, D., Singh, A., Haugen, M., Beddows, D. S., Diez, S., Murphy, K. L., Edwards, P. M., Boies, A., Harrison, R. M., Pope, F. D. 2021; 14 (6): 4139-4155

  View details for DOI 10.5194/amt-14-4139-2021

  View details for Web of Science ID 000661252300002

• Multiscale numerical modeling of solid particle penetration and hydrocarbons removal in a catalytic stripper AEROSOL SCIENCE AND TECHNOLOGY Woo, M., Giannopoulos, G., Rahman, M., Swanson, J., Stettler, M. J., Boies, A. M. 2021; 55 (9): 987-1000

  View details for DOI 10.1080/02786826.2021.1909700

  View details for Web of Science ID 000644246900001

• Chemical characterization of size-selected nanoparticles emitted by a gasoline direct injection engine: Impact of a catalytic stripper FUEL Duca, D., Rahman, M., Carpentier, Y., Pirim, C., Boies, A., Focsa, C. 2021; 294

  View details for DOI 10.1016/j.fuel.2021.120317

  View details for Web of Science ID 000640907900006

• Vanadium Dioxide Cathodes for High-Rate Photo-Rechargeable Zinc-Ion Batteries ADVANCED ENERGY MATERIALS Deka Boruah, B., Mathieson, A., Park, S., Zhang, X., Wen, B., Tan, L., Boies, A., De Volder, M. 2021; 11 (13)

  View details for DOI 10.1002/aenm.202100115

  View details for Web of Science ID 000623226000001

• Generating an aerosol of homogeneous, non-spherical particles and measuring their bipolar charge distribution JOURNAL OF AEROSOL SCIENCE Johnson, T. J., Nishida, R. T., Zhang, X., Symonds, J. R., Olfert, J. S., Boies, A. M. 2021; 153

  View details for DOI 10.1016/j.jaerosci.2020.105705

  View details for Web of Science ID 000614040000002

• Surfactant-free synthesis of copper nanoparticles and gas phase integration in CNT-composite materials NANOSCALE ADVANCES Brunet, P., McGlynn, R. J., Alessi, B., Smail, F., Boies, A., Maguire, P., Mariotti, D. 2021; 3 (3): 781-788

  Abstract

  Copper nanoparticles (Cu-NPs) represent a viable low-cost alternative to replace bulk copper or other more expensive NPs (e.g. gold or silver) in various applications such as electronics for electrical contact materials or high conductivity materials. This study deals with the synthesis of well dispersed Cu-NPs by using an Ar + H2 microplasma using a solid copper precursor. The morphological analysis is carried out by electron microscopy showing particles with a mean diameter of 8 nm. Crystallinity and chemical analyses were also carried out by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. In the second step, the Cu-NPs were successfully deposited onto porous carbon nanotube ribbons; surface coverage and the penetration depth of the Cu-NPs inside the CNT ribbon structure were investigated as these can be beneficial for a number of applications. The oxidation state of the Cu-NPs was also studied in detail under different conditions.

  View details for DOI 10.1039/d0na00922a

  View details for Web of Science ID 000616675500015

  View details for PubMedID 36133850

  View details for PubMedCentralID PMC9419625

• A fork in the road: Which energy pathway offers the greatest energy efficiency and CO₂ reduction potential for low-carbon vehicles? APPLIED ENERGY Haugen, M. J., Paoli, L., Cullen, J., Cebon, D., Boies, A. M. 2021; 283

  View details for DOI 10.1016/j.apenergy.2020.116295

  View details for Web of Science ID 000613289500005

• Open-source modelling of aerosol dynamics and computational fluid dynamics: Nodal method for nucleation, coagulation, and surface growth COMPUTER PHYSICS COMMUNICATIONS Woo, M., Nishida, R. T., Schriefl, M. A., Stettler, M. J., Boies, A. M. 2021; 261

  View details for DOI 10.1016/j.cpc.2020.107765

  View details for Web of Science ID 000618285100006

• Accelerated measurements of aerosol size distributions by continuously scanning the aerodynamic aerosol classifier AEROSOL SCIENCE AND TECHNOLOGY Johnson, T. J., Symonds, J. R., Olfert, J. S., Boies, A. M. 2021; 55 (2): 119-141

  View details for DOI 10.1080/02786826.2020.1830941

  View details for Web of Science ID 000591721400001

• Photo-rechargeable Zinc-Ion Capacitors using V₂O₅-Activated Carbon Electrodes ACS ENERGY LETTERS Boruah, B., Wen, B., Nagane, S., Zhang, X., Stranks, S. D., Boies, A., De Volder, M. 2020; 5 (10): 3132-3139

  View details for DOI 10.1021/acsenergylett.0c01528

  View details for Web of Science ID 000580586400005

• Modelling and evaluation of a biomethane truck for transport performance and cost TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT Madhusudhanan, A. K., Na, X., Boies, A., Cebon, D. 2020; 87

  View details for DOI 10.1016/j.trd.2020.102530

  View details for Web of Science ID 000581017900048

• High energy density anodes using hybrid Li intercalation and plating mechanisms on natural graphite ENERGY & ENVIRONMENTAL SCIENCE Son, Y., Lee, T., Wen, B., Ma, J., Jo, C., Cho, Y., Boies, A., Cho, J., De Volder, M. 2020; 13 (10): 3723-3731

  View details for DOI 10.1039/d0ee02230f

  View details for Web of Science ID 000579868500034

• Precise Catalyst Production for Carbon Nanotube Synthesis with Targeted Structure Enrichment CATALYSTS Zhang, X., Deng, Y., Graves, B., De Volder, M., Boies, A. 2020; 10 (9)

  View details for DOI 10.3390/catal10091087

  View details for Web of Science ID 000580290800001

• High-precision solid catalysts for investigation of carbon nanotube synthesis and structure SCIENCE ADVANCES Zhang, X., Graves, B., De Volder, M., Yang, W., Johnson, T., Wen, B., Su, W., Nishida, R., Xie, S., Boies, A. 2020; 6 (40)

  Abstract

  The direct growth of single-walled carbon nanotubes (SWCNTs) with narrow chiral distribution remains elusive despite substantial benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT and more generally nanomaterial synthesis, but understanding their effect is limited. Solid catalysts show promise in achieving chirality-controlled growth, but poor size control and synthesis efficiency hampers advancement. Here, we demonstrate the first synthesis of refractory metal nanoparticles (W, Mo, and Re) with near-monodisperse sizes. High concentrations (N = 105 to 107 cm-3) of nanoparticles (diameter 1 to 5 nm) are produced and reduced in a single process, enabling SWCNT synthesis with controlled chiral angles of 19° ± 5°, demonstrating abundance >93%. These results confirm the interface thermodynamics and kinetic growth theory mechanism, which has been extended here to include temporal dependence of fast-growing chiralities. The solid catalysts are further shown effective via floating catalyst growth, offering efficient production possibilities.

  View details for DOI 10.1126/sciadv.abb6010

  View details for Web of Science ID 000579157800025

  View details for PubMedID 32998901

  View details for PubMedCentralID PMC7527216

• Thermodynamic and experimental evaluation of a cloud chamber for ultrafine particle detection SENSORS AND ACTUATORS A-PHYSICAL Yang, W., Boies, A. M. 2020; 310

  View details for DOI 10.1016/j.sna.2020.111986

  View details for Web of Science ID 000541144000014

• Weakly Coupled Piezoelectric MEMS Resonators for Aerosol Sensing SENSORS Chellasivalingam, M., Imran, H., Pandit, M., Boies, A. M., Seshia, A. A. 2020; 20 (11)

  Abstract

  This paper successfully demonstrates the potential of weakly coupled piezoelectric MEMS (Micro-Electro-Mechanical Systems) gravimetric sensors for the detection of ultra-fine particulates. As a proof-of-principle, the detection of diesel soot particles of 100 nanometres or less is demonstrated. A practical monitoring context also exists for diesel soot particles originating from combustion engines, as they are of serious health concern. The MEMS sensors employed in this work operate on the principle of vibration mode-localisation employing an amplitude ratio shift output metric for readout. Notably, gains are observed while comparing parametric sensitivities and the input referred stability for amplitude ratio and resonant frequency variations, demonstrating that the amplitude ratio output metric is particularly suitable for long-term measurements. The soot particle mass directly estimated using coupled MEMS resonators can be correlated to the mass, indirectly estimated using the condensation particle counter used as the reference instrument.

  View details for DOI 10.3390/s20113162

  View details for Web of Science ID 000552737900155

  View details for PubMedID 32498465

  View details for PubMedCentralID PMC7309065

• Measuring the bipolar charge distribution of nanoparticles: Review of methodologies and development using the Aerodynamic Aerosol Classifier JOURNAL OF AEROSOL SCIENCE Johnson, T. J., Nishida, R. T., Irwin, M., Symonds, J. R., Olfert, J. S., Boies, A. M. 2020; 143

  View details for DOI 10.1016/j.jaerosci.2020.105526

  View details for Web of Science ID 000523595800002

• Comprehensive characterization of mainstream marijuana and tobacco smoke SCIENTIFIC REPORTS Graves, B. M., Johnson, T. J., Nishida, R. T., Dias, R. P., Savareear, B., Harynuk, J. J., Kazemimanesh, M., Olfert, J. S., Boies, A. M. 2020; 10 (1): 7160

  Abstract

  Recent increases in marijuana use and legalization without adequate knowledge of the risks necessitate the characterization of the billions of nanoparticles contained in each puff of smoke. Tobacco smoke offers a benchmark given that it has been extensively studied. Tobacco and marijuana smoke particles are quantitatively similar in volatility, shape, density and number concentration, albeit with differences in size, total mass and chemical composition. Particles from marijuana smoke are on average 29% larger in mobility diameter than particles from tobacco smoke and contain 3.4× more total mass. New measurements of semi-volatile fractions determine over 97% of the mass and volume of the particles from either smoke source are comprised of semi-volatile compounds. For tobacco and marijuana smoke, respectively, 4350 and 2575 different compounds are detected, of which, 670 and 536 (231 in common) are tentatively identified, and of these, 173 and 110 different compounds (69 in common) are known to cause negative health effects through carcinogenic, mutagenic, teratogenic, or other toxic mechanisms. This study demonstrates striking similarities between marijuana and tobacco smoke in terms of their physical and chemical properties.

  View details for DOI 10.1038/s41598-020-63120-6

  View details for Web of Science ID 000560713100011

  View details for PubMedID 32345986

  View details for PubMedCentralID PMC7188852

• From Collisions to Bundles: An Adaptive Coarse-Grained Model for the Aggregation of High-Aspect-Ratio Carbon Nanotubes JOURNAL OF PHYSICAL CHEMISTRY C Kateris, N., Kloza, P. A., Qiao, R., Elliott, J. A., Boies, A. 2020; 124 (15): 8359-8370

  View details for DOI 10.1021/acs.jpcc.9b10479

  View details for Web of Science ID 000526319300032

• Plasma production of nanomaterials for energy storage: continuous gas-phase synthesis of metal oxide CNT materials <i>via</i> a microwave plasma NANOSCALE Graves, B., Engelke, S., Jo, C., Baldovi, H. G., De la Verpilliere, J., De Volder, M., Boies, A. 2020; 12 (8): 5196-5208

  Abstract

  In this work we show for the first time that a continuous plasma process can synthesize materials from bulk industrial powders to produce hierarchical structures for energy storage applications. The plasma production process's unique advantages are that it is fast, inexpensive, and scalable due to its high energy density that enables low-cost precursors. The synthesized hierarchical material is comprised of iron oxide and aluminum oxide aggregate particles and carbon nanotubes grown in situ from the iron particles. New aerosol-based methods were used for the first time on a battery material to characterize aggregate and primary particle morphologies, while showing good agreement with observations from TEM measurements. As an anode for lithium ion batteries, a reversible capacity of 870 mA h g-1 based on metal oxide mass was observed and the material showed good recovery from high rate cycling. The high rate of material synthesis (∼10 s residence time) enables this plasma hierarchical material synthesis platform to be optimized as a means for energetic material production for the global energy storage material supply chain.

  View details for DOI 10.1039/c9nr08886e

  View details for Web of Science ID 000519117800039

  View details for PubMedID 32073024

• A Simple Method for Measuring Fine-to-Ultrafine Aerosols Using Bipolar Charge Equilibrium ACS SENSORS Nishida, R. T., Johnson, T. J., Hassim, J. S., Graves, B. M., Boies, A. M., Hochgreb, S. 2020; 5 (2): 447-453

  Abstract

  Low-cost methods for measuring airborne microparticles and nanoparticles (aerosols) have remained elusive despite the increasing concern of health impacts from ambient, urban, and indoor sources. While bipolar ion sources are common in smoke alarms, this work is the first to exploit the mean charge on an aerosol resulting from a bipolar charge equilibrium and establish experimentally its correlation to properties of the aerosol particle size distribution. The net current produced from this mean particle charge is demonstrated to be linearly proportional to the product of the mean particle diameter and total number concentration (i ∼ Nd̅) for two bipolar ion sources (85Kr and 241Am). This conclusion is supported by simple equations derived from well-established bipolar charging theory. The theory predicts that the mean charge on the aerosol particles reaches an equilibrium, which, importantly, is independent of the concentration of charging ions. Furthermore, in situ measurements of a roadside aerosol demonstrate that the sensing method yields results in good agreement (R2 = 0.979) with existing portable and laboratory-grade aerosol instruments. The simplicity, stability, and cost of the bipolar ion source overcome challenges of other portable sensors, increasing the feasibility of widespread sensor deployment to monitor ultrafine particle characteristics, which are relevant to lung deposition and by extension, human health.

  View details for DOI 10.1021/acssensors.9b02143

  View details for Web of Science ID 000517856700021

  View details for PubMedID 31922393

• High-temperature condensation particle counter using a systematically selected dedicated working fluid for automotive applications AEROSOL SCIENCE AND TECHNOLOGY Kupper, M., Kraft, M., Boies, A., Bergmann, A. 2020; 54 (4): 381-395

  View details for DOI 10.1080/02786826.2019.1702920

  View details for Web of Science ID 000505646900001

• MASS TUNING IN WEAKLY COUPLED LOW-Q PIEZOELECTRIC MEMS RESONATOR ARRAYS FOR PARTICULATE SENSING Chellasivalingam, M., Graves, B., Boies, A., Seshia, A. A., IEEE IEEE. 2020: 761-764

  View details for DOI 10.1109/mems46641.2020.9056426

  View details for Web of Science ID 000569381600197

• MEMS Based Gravimetric Sensor for the Detection of Ultra-Fine Aerosol Particles Chellasivalingam, M., Somappa, L., Boies, A. M., Baghini, M., Seshia, A. A., IEEE IEEE. 2020

  View details for DOI 10.1109/sensors47125.2020.9278870

  View details for Web of Science ID 000646236300286

• Continuous-Flow Synthesis of Carbon-Coated Silicon/Iron Silicide Secondary Particles for Li-Ion Batteries ACS NANO Jo, C., Groombridge, A. S., De La Verpilliere, J., Lee, J., Son, Y., Liang, H., Boies, A. M., De Volder, M. 2020; 14 (1): 698-707

  Abstract

  The development of better Li-ion battery (LIB) electrodes requires an orchestrated effort to improve the active materials as well as the electron and ion transport in the electrode. In this paper, iron silicide is studied as an anode material for LIBs because of its higher conductivity and lower volume expansion compared to pure Si particles. In addition, carbon nanotubes (CNTs) can be synthesized from the surface of iron-silicides using a continuous flow coating process where precursors are first spray dried into micrometer-scale secondary particles and are then flown through a chemical vapor deposition (CVD) reactor. Some CNTs are formed inside the secondary particles, which are important for short-range electrical transport and good utilization of the active material. Surface-bound CNTs on the secondary particles may help establish a long-range conductivity. We also observed that these spherical secondary particles allow for better electrode coating quality, cyclability, and rate performance than unstructured materials with the same composition. The developed electrodes retain a gravimetric capacity of 1150 mAh/g over 300 cycles at 1A/g as well as a 43% capacity retention at a rate of 5 C. Further, blended electrodes with graphite delivered a 539 mAh/g with high electrode density (∼1.6 g/cm3) and areal capacity (∼3.5 mAh/cm2) with stable cycling performance.

  View details for DOI 10.1021/acsnano.9b07473

  View details for Web of Science ID 000510531500060

  View details for PubMedID 31834775

  View details for PubMedCentralID PMC6990505

• Direct spinning of CNT fibres: Past, present and future scale up CARBON Smail, F., Boies, A., Windle, A. 2019; 152: 218-232

  View details for DOI 10.1016/j.carbon.2019.05.024

  View details for Web of Science ID 000483384900024

• The mechanical and electrical properties of direct-spun carbon nanotube mat-epoxy composites CARBON Tan, W., Stallard, J. C., Smail, F. R., Boies, A. M., Fleck, N. A. 2019; 150: 489-504

  View details for DOI 10.1016/j.carbon.2019.04.118

  View details for Web of Science ID 000472193400052

• Agglomeration Dynamics of 1D Materials: Gas-Phase Collision Rates of Nanotubes and Nanorods SMALL Boies, A. M., Hoecker, C., Bhalerao, A., Kateris, N., de la Verpilliere, J., Graves, B., Smail, F. 2019; 15 (27): e1900520

  Abstract

  The agglomeration and self-assembly of gas-phase 1D materials in anthropogenic and natural systems dictate their resulting nanoscale morphology, multiscale hierarchy, and ultimate macroscale properties. Brownian motion induces collisions, upon which 1D materials often restructure to form bundles and can lead to aerogels. Herein, the first results of collision rates for 1D nanomaterials undergoing thermal transport are presented. The Langevin dynamic simulations of nanotube rotation and translation demonstrate that the collision kernels for rigid nanotubes or nanorods are ≈10 times greater than spherical systems. Resulting reduced order equations allow straightforward calculation of the physical parameters to determine the collision kernel for straight and curved 1D materials from 102 to 106 nm length. The collision kernels of curved 1D structures increase ≈1.3 times for long (>102 nm), and ≈5 times for short (≈102 nm) relative to rigid materials. Applications of collision frequencies allow the first kinetic analysis of aerogel self-assembly from gas-phase carbon nanotubes (CNTs). The timescales for CNT collision and bundle formation (0.3-42 s) agree with empirical residence times in CNT reactors (3-15 s). These results provide insights into the CNT length, number, and timescales required for aerogel formation, which bolsters our understanding of mass-produced 1D aerogel materials.

  View details for DOI 10.1002/smll.201900520

  View details for Web of Science ID 000477930000013

  View details for PubMedID 31120182

• A methodology to relate black carbon particle number and mass emissions JOURNAL OF AEROSOL SCIENCE Teoh, R., Stettler, M. J., Majumdar, A., Schumann, U., Graves, B., Boies, A. M. 2019; 132: 44-59

  View details for DOI 10.1016/j.jaerosci.2019.03.006

  View details for Web of Science ID 000464337700005

• Using portable emissions measurement systems (PEMS) to derive more accurate estimates of fuel use and nitrogen oxides emissions from modern Euro 6 passenger cars under real-world driving conditions APPLIED ENERGY Bishop, J. K., Molden, N., Boies, A. M. 2019; 242: 942-973

  View details for DOI 10.1016/j.apenergy.2019.03.047

  View details for Web of Science ID 000470045800073

• Mapping the parameter space for direct-spun carbon nanotube aerogels CARBON Weller, L., Smail, F. R., Elliott, J. A., Windle, A. H., Boies, A. M., Hochgreb, S. 2019; 146: 789-812

  View details for DOI 10.1016/j.carbon.2019.01.091

  View details for Web of Science ID 000465408900085

• High-fidelity characterization on anisotropic thermal conductivity of carbon nanotube sheets and on their effects of thermal enhancement of nanocomposites NANOTECHNOLOGY Zhang, X., Tan, W., Smail, F., De Volder, M., Fleck, N., Boies, A. 2018; 29 (36): 365708

  Abstract

  Some assemblies of nanomaterials, like carbon nanotube (CNT) sheet or film, always show outstanding and anisotropic thermal properties. However, there is still a lack of comprehensive thermal conductivity (κ) characterizations on CNT sheets, as well as a lack of estimations of their true contributions on thermal enhancement of polymer composites when used as additives. Always, these characterizations were hindered by the low heat capacity, anisotropic thermal properties or low electrical conductivity of assemblies and their nanocomposites. The transient κ measurement and calculations were also hampered by accurate determination of parameters, like specific heat capacity, density and cross-section, which could be difficult and controversial for nanomaterials, like CNT sheets. Here, to measure anisotropic κ of CNT sheets directly with high fidelity, we modified the conventional steady-state method by measuring under vacuum and by infrared camera, and then comparing temperature profiles on both reference standard material and a CNT sheet sample. The highly anisotropic thermal conductivities of CNT sheets were characterized comprehensively, with κ/ρ in alignment direction as ∼95 mW m2 K-1 kg-1. Furthermore, by comparing the measured thermal properties of different CNT-epoxy resin composites, the heat conduction pathway created by the CNT hierarchical network was demonstrated to remain intact after the in situ polymerization and curing process. The reliable and direct κ measurement rituals used here, dedicated to nanomaterials, will be also essential to assist in assemblies' application to heat dissipation and composite thermal enhancement.

  View details for DOI 10.1088/1361-6528/aacd7b

  View details for Web of Science ID 000437669000002

  View details for PubMedID 29916810

• Continuous flow chemical vapour deposition of carbon nanotube sea urchins NANOSCALE de La Verpilliere, J., Jessl, S., Saeed, K., Ducati, C., De Volder, M., Boies, A. 2018; 10 (16): 7780-7791

  Abstract

  Hybrid structures consisting of functional materials enhanced by carbon nanotubes (CNTs) have potential for a variety of high impact applications, as shown by the impressive progress in sensing and mechanical applications enabled by CNT-enhanced materials. The hierarchical organisation of CNTs with other materials is key to the design of macroscale devices benefiting from the unique properties of individual CNTs, provided CNT density, morphology and binding with other materials are optimized. In this paper, we provide an analysis of a continuous aerosol process to create a hybrid hierarchical sea urchin structure with CNTs organized around a functional metal oxide core. We propose a new mechanism for the growth of these carbon nanotube sea urchins (CNTSU) and give new insight into their chemical composition. To corroborate the new mechanism, we examine the influence of CNT growth conditions on CNTSU morphology and demonstrate a new in-line characterisation technique to continuously monitor aerosol CNT growth during synthesis, which enables industrial-scale production optimization. Based upon the new formation mechanism we describe the first substrate-based chemical vapour deposition growth of CNTSUs which increases CNT length and improves G to D ratio, which also allows for the formation of CNTSU carpets with unique structures.

  View details for DOI 10.1039/c7nr09534a

  View details for Web of Science ID 000431030000052

  View details for PubMedID 29662980

• Measuring aerosol size distributions with the aerodynamic aerosol classifier AEROSOL SCIENCE AND TECHNOLOGY Johnson, T. J., Irwin, M., Symonds, J. R., Olfert, J. S., Boies, A. M. 2018; 52 (6): 655-665

  View details for DOI 10.1080/02786826.2018.1440063

  View details for Web of Science ID 000432629100005

• Measuring ultrafine aerosols by direct photoionization and charge capture in continuous flow AEROSOL SCIENCE AND TECHNOLOGY Nishida, R. T., Boies, A. M., Hochgreb, S. 2018; 52 (5): 546-556

  View details for DOI 10.1080/02786826.2018.1430350

  View details for Web of Science ID 000430091700007

• The Dependence of CNT Aerogel Synthesis on Sulfur-driven Catalyst Nucleation Processes and a Critical Catalyst Particle Mass Concentration SCIENTIFIC REPORTS Hoecker, C., Smail, F., Pick, M., Weller, L., Boies, A. M. 2017; 7: 14519

  Abstract

  The floating catalyst chemical vapor deposition (FC-CVD) process permits macro-scale assembly of nanoscale materials, enabling continuous production of carbon nanotube (CNT) aerogels. Despite the intensive research in the field, fundamental uncertainties remain regarding how catalyst particle dynamics within the system influence the CNT aerogel formation, thus limiting effective scale-up. While aerogel formation in FC-CVD reactors requires a catalyst (typically iron, Fe) and a promotor (typically sulfur, S), their synergistic roles are not fully understood. This paper presents a paradigm shift in the understanding of the role of S in the process with new experimental studies identifying that S lowers the nucleation barrier of the catalyst nanoparticles. Furthermore, CNT aerogel formation requires a critical threshold of FexCy > 160 mg/m3, but is surprisingly independent of the initial catalyst diameter or number concentration. The robustness of the critical catalyst mass concentration principle is proved further by producing CNTs using alternative catalyst systems; Fe nanoparticles from a plasma spark generator and cobaltocene and nickelocene precursors. This finding provides evidence that low-cost and high throughput CNT aerogel routes may be achieved by decoupled and enhanced catalyst production and control, opening up new possibilities for large-scale CNT synthesis.

  View details for DOI 10.1038/s41598-017-14775-1

  View details for Web of Science ID 000414415000019

  View details for PubMedID 29109427

  View details for PubMedCentralID PMC5673953

• The influence of carbon source and catalyst nanoparticles on CVD synthesis of CNT aerogel CHEMICAL ENGINEERING JOURNAL Hoecker, C., Smail, F., Pick, M., Boies, A. 2017; 314: 388-395

  View details for DOI 10.1016/j.cej.2016.11.157

  View details for Web of Science ID 000395211100040

• How Well Do We Know the Future of CO₂ Emissions? Projecting Fleet Emissions from Light Duty Vehicle Technology Drivers ENVIRONMENTAL SCIENCE & TECHNOLOGY Martin, N. D., Bishop, J. K., Boies, A. M. 2017; 51 (5): 3093-3101

  Abstract

  While the UK has committed to reduce CO2 emissions to 80% of 1990 levels by 2050, transport accounts for nearly a fourth of all emissions and the degree to which decarbonization can occur is highly uncertain. We present a new methodology using vehicle and powertrain parameters within a Bayesian framework to determine the impact of engineering vehicle improvements on fuel consumption and CO2 emissions. Our results show how design changes in vehicle parameters (e.g., mass, engine size, and compression ratio) result in fuel consumption improvements from a fleet-wide mean of 5.6 L/100 km in 2014 to 3.0 L/100 km by 2030. The change in vehicle efficiency coupled with increases in vehicle numbers and fleet-wide activity result in a total fleet-wide reduction of 41 ± 10% in 2030, relative to 2012. Concerted internal combustion engine improvements result in a 48 ± 10% reduction of CO2 emissions, while efforts to increase the number of diesel vehicles within the fleet had little additional effect. Increasing plug-in and all-electric vehicles reduced CO2 emissions by less (42 ± 10% reduction) than concerted internal combustion engines improvements. However, if the grid decarbonizes, electric vehicles reduce emissions by 45 ± 9% with further reduction potential to 2050.

  View details for DOI 10.1021/acs.est.6b04746

  View details for Web of Science ID 000395963800070

  View details for PubMedID 28178418

• Effective density and volatility of particles sampled from a helicopter gas turbine engine AEROSOL SCIENCE AND TECHNOLOGY Olfert, J. S., Dickau, M., Momenimovahed, A., Saffaripour, M., Thomson, K., Smallwood, G., Stettler, M. J., Boies, A., Sevcenco, Y., Crayford, A., Johnson, M. 2017; 51 (6): 704-714

  View details for DOI 10.1080/02786826.2017.1292346

  View details for Web of Science ID 000400673900005

• Engine maps of fuel use and emissions from transient driving cycles APPLIED ENERGY Bishop, J. K., Stettler, M. J., Molden, N., Boies, A. M. 2016; 183: 202-217

  View details for DOI 10.1016/j.apenergy.2016.08.175

  View details for Web of Science ID 000391897600017

• Quantifying the role of vehicle size, powertrain technology, activity and consumer behaviour on new UK passenger vehicle fleet energy use and emissions under different policy objectives APPLIED ENERGY Bishop, J. K., Martin, N. D., Boies, A. M. 2016; 180: 196-212

  View details for DOI 10.1016/j.apenergy.2016.07.111

  View details for Web of Science ID 000383291900016

• Fuel Sulfur and Iron Additives Contribute to the Formation of Carbon Nanotube-like Structures in an Internal Combustion Engine ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Swanson, J. J., Febo, R., Boies, A. M., Kittelson, D. B. 2016; 3 (10): 364-368

  View details for DOI 10.1021/acs.estlett.6b00313

  View details for Web of Science ID 000385339900004

• Greenhouse Gas and Noxious Emissions from Dual Fuel Diesel and Natural Gas Heavy Goods Vehicles ENVIRONMENTAL SCIENCE & TECHNOLOGY Stettler, M. J., Midgley, W. B., Swanson, J. J., Cebon, D., Boies, A. M. 2016; 50 (4): 2018-2026

  Abstract

  Dual fuel diesel and natural gas heavy goods vehicles (HGVs) operate on a combination of the two fuels simultaneously. By substituting diesel for natural gas, vehicle operators can benefit from reduced fuel costs and as natural gas has a lower CO2 intensity compared to diesel, dual fuel HGVs have the potential to reduce greenhouse gas (GHG) emissions from the freight sector. In this study, energy consumption, greenhouse gas and noxious emissions for five after-market dual fuel configurations of two vehicle platforms are compared relative to their diesel-only baseline values over transient and steady state testing. Over a transient cycle, CO2 emissions are reduced by up to 9%; however, methane (CH4) emissions due to incomplete combustion lead to CO2e emissions that are 50-127% higher than the equivalent diesel vehicle. Oxidation catalysts evaluated on the vehicles at steady state reduced CH4 emissions by at most 15% at exhaust gas temperatures representative of transient conditions. This study highlights that control of CH4 emissions and improved control of in-cylinder CH4 combustion are required to reduce total GHG emissions of dual fuel HGVs relative to diesel vehicles.

  View details for DOI 10.1021/acs.est.5b04240

  View details for Web of Science ID 000370454200045

  View details for PubMedID 26757000

• Improved sizing of soot primary particles using mass-mobility measurements AEROSOL SCIENCE AND TECHNOLOGY Dastanpour, R., Rogak, S. N., Graves, B., Olfert, J., Eggersdorfer, M. L., Boies, A. M. 2016; 50 (2): 101-109

  View details for DOI 10.1080/02786826.2015.1130796

  View details for Web of Science ID 000368707600001

• Methodology for quantifying the volatile mixing state of an aerosol AEROSOL SCIENCE AND TECHNOLOGY Dickau, M., Olfert, J., Stettler, M. J., Boies, A., Momenimovahed, A., Thomson, K., Smallwood, G., Johnson, M. 2016; 50 (8): 759-772

  View details for DOI 10.1080/02786826.2016.1185509

  View details for Web of Science ID 000379625400001

• Catalyst nanoparticle growth dynamics and their influence on product morphology in a CVD process for continuous carbon nanotube synthesis CARBON Hoecker, C., Smail, F., Bajada, M., Pick, M., Boies, A. 2016; 96: 116-124

  View details for DOI 10.1016/j.carbon.2015.09.050

  View details for Web of Science ID 000366078000015

• Energy, carbon dioxide and water use implications of hydrous ethanol production ENERGY CONVERSION AND MANAGEMENT Saffy, H. A., Northrop, W. F., Kittelson, D. B., Boles, A. M. 2015; 105: 900-907

  View details for DOI 10.1016/j.enconman.2015.08.039

  View details for Web of Science ID 000363068900083

• Can UK passenger vehicles be designed to meet 2020 emissions targets? A novel methodology to forecast fuel consumption with uncertainty analysis APPLIED ENERGY Martin, N. D., Bishop, J. K., Choudhary, R., Boies, A. M. 2015; 157: 929-939

  View details for DOI 10.1016/j.apenergy.2015.03.044

  View details for Web of Science ID 000364249200089

• Air quality evaluation of London Paddington train station ENVIRONMENTAL RESEARCH LETTERS Chong, U., Swanson, J. J., Boies, A. M. 2015; 10 (9)

  View details for DOI 10.1088/1748-9326/10/9/094012

  View details for Web of Science ID 000367141000015

• Unsteady bipolar diffusion charging in aerosol neutralisers: A non-dimensional approach to predict charge distribution equilibrium behaviour JOURNAL OF AEROSOL SCIENCE de La Verpilliere, J. L., Swanson, J. J., Boies, A. M. 2015; 86: 55-68

  View details for DOI 10.1016/j.jaerosci.2015.03.006

  View details for Web of Science ID 000357551300006

• Effective Density and Mass-Mobility Exponent of Aircraft Turbine Particulate Matter JOURNAL OF PROPULSION AND POWER Johnson, T. J., Olfert, J. S., Symonds, J. R., Johnson, M., Rindlisbacher, T., Swanson, J. J., Boies, A. M., Thomson, K., Smallwood, G., Walters, D., Sevcenco, Y., Crayford, A., Dastanpour, R., Rogak, S. N., Durdina, L., Bahk, Y., Brem, B., Wang, J. 2015; 31 (2): 573-582

  View details for DOI 10.2514/1.B35367

  View details for Web of Science ID 000360839300009

• Particle Emission Characteristics of a Gas Turbine with a Double Annular Combustor AEROSOL SCIENCE AND TECHNOLOGY Boies, A. M., Stettler, M. J., Swanson, J. J., Johnson, T. J., Olfert, J. S., Johnson, M., Eggersdorfer, M. L., Rindlisbacher, T., Wang, J., Thomson, K., Smallwood, G., Sevcenco, Y., Walters, D., Williams, P. I., Corbin, J., Mensah, A. A., Symonds, J., Dastanpour, R., Rogak, S. N. 2015; 49 (9): 842-855

  View details for DOI 10.1080/02786826.2015.1078452

  View details for Web of Science ID 000364849900006

• Response to Comment on "Effects of Ethanol on Vehicle Energy Efficiency and Implications on Ethanol Life-Cycle Greenhouse Gas Analysis" ENVIRONMENTAL SCIENCE & TECHNOLOGY Yan, X., Inderwildi, O. R., King, D. A., Boies, A. M. 2014; 48 (16): 9953-9954

  View details for DOI 10.1021/es503420y

  View details for Web of Science ID 000340701800125

  View details for PubMedID 25089580

• Cost-effectiveness of alternative powertrains for reduced energy use and CO₂ emissions in passenger vehicles APPLIED ENERGY Bishop, J. K., Martin, N. D., Boies, A. M. 2014; 124: 44-61

  View details for DOI 10.1016/j.apenergy.2014.02.019

  View details for Web of Science ID 000336338800005

• Lifecycle greenhouse gas footprint and minimum selling price of renewable diesel and jet fuel from fermentation and advanced fermentation production technologies ENERGY & ENVIRONMENTAL SCIENCE Staples, M. D., Malina, R., Olcay, H., Pearlson, M. N., Hileman, J. I., Boies, A., Barrett, S. H. 2014; 7 (5): 1545-1554

  View details for DOI 10.1039/c3ee43655a

  View details for Web of Science ID 000335013700002

• Air Quality and Climate Impacts of Alternative Bus Technologies in Greater London ENVIRONMENTAL SCIENCE & TECHNOLOGY Chong, U., Yim, S. L., Barrett, S. H., Boies, A. M. 2014; 48 (8): 4613-4622

  Abstract

  The environmental impact of diesel-fueled buses can potentially be reduced by the adoption of alternative propulsion technologies such as lean-burn compressed natural gas (LB-CNG) or hybrid electric buses (HEB), and emissions control strategies such as a continuously regenerating trap (CRT), exhaust gas recirculation (EGR), or selective catalytic reduction with trap (SCRT). This study assessed the environmental costs and benefits of these bus technologies in Greater London relative to the existing fleet and characterized emissions changes due to alternative technologies. We found a >30% increase in CO2 equivalent (CO2e) emissions for CNG buses, a <5% change for exhaust treatment scenarios, and a 13% (90% confidence interval 3.8-20.9%) reduction for HEB relative to baseline CO2e emissions. A multiscale regional chemistry-transport model quantified the impact of alternative bus technologies on air quality, which was then related to premature mortality risk. We found the largest decrease in population exposure (about 83%) to particulate matter (PM2.5) occurred with LB-CNG buses. Monetized environmental and investment costs relative to the baseline gave estimated net present cost of LB-CNG or HEB conversion to be $187 million ($73 million to $301 million) or $36 million ($-25 million to $102 million), respectively, while EGR or SCRT estimated net present costs were $19 million ($7 million to $32 million) or $15 million ($8 million to $23 million), respectively.

  View details for DOI 10.1021/es4055274

  View details for Web of Science ID 000334658400045

  View details for PubMedID 24654768

• Updated Correlation Between Aircraft Smoke Number and Black Carbon Concentration AEROSOL SCIENCE AND TECHNOLOGY Stettler, M. J., Swanson, J. J., Barrett, S. H., Boies, A. M. 2013; 47 (11): 1205-1214

  View details for DOI 10.1080/02786826.2013.829908

  View details for Web of Science ID 000324459700006

• Distributed energy resource system optimisation using mixed integer linear programming ENERGY POLICY Omu, A., Choudhary, R., Boies, A. 2013; 61: 249-266

  View details for DOI 10.1016/j.enpol.2013.05.009

  View details for Web of Science ID 000325443500026

• Global Civil Aviation Black Carbon Emissions ENVIRONMENTAL SCIENCE & TECHNOLOGY Stettler, M. J., Boies, A. M., Petzold, A., Barrett, S. H. 2013; 47 (18): 10397-10404

  Abstract

  Aircraft black carbon (BC) emissions contribute to climate forcing, but few estimates of BC emitted by aircraft at cruise exist. For the majority of aircraft engines the only BC-related measurement available is smoke number (SN)-a filter based optical method designed to measure near-ground plume visibility, not mass. While the first order approximation (FOA3) technique has been developed to estimate BC mass emissions normalized by fuel burn [EI(BC)] from SN, it is shown that it underestimates EI(BC) by >90% in 35% of directly measured cases (R(2) = -0.10). As there are no plans to measure BC emissions from all existing certified engines-which will be in service for several decades-it is necessary to estimate EI(BC) for existing aircraft on the ground and at cruise. An alternative method, called FOX, that is independent of the SN is developed to estimate BC emissions. Estimates of EI(BC) at ground level are significantly improved (R(2) = 0.68), whereas estimates at cruise are within 30% of measurements. Implementing this approach for global civil aviation estimated aircraft BC emissions are revised upward by a factor of ~3. Direct radiative forcing (RF) due to aviation BC emissions is estimated to be ~9.5 mW/m(2), equivalent to ~1/3 of the current RF due to aviation CO2 emissions.

  View details for DOI 10.1021/es401356v

  View details for Web of Science ID 000330096000041

  View details for PubMedID 23844612

• Effects of Ethanol on Vehicle Energy Efficiency and Implications on Ethanol Life-Cycle Greenhouse Gas Analysis ENVIRONMENTAL SCIENCE & TECHNOLOGY Yan, X., Inderwildi, O. R., King, D. A., Boies, A. M. 2013; 47 (11): 5535-5544

  Abstract

  Bioethanol is the world's largest-produced alternative to petroleum-derived transportation fuels due to its compatibility within existing spark-ignition engines and its relatively mature production technology. Despite its success, questions remain over the greenhouse gas (GHG) implications of fuel ethanol use with many studies showing significant impacts of differences in land use, feedstock, and refinery operation. While most efforts to quantify life-cycle GHG impacts have focused on the production stage, a few recent studies have acknowledged the effect of ethanol on engine performance and incorporated these effects into the fuel life cycle. These studies have broadly asserted that vehicle efficiency increases with ethanol use to justify reducing the GHG impact of ethanol. These results seem to conflict with the general notion that ethanol decreases the fuel efficiency (or increases the fuel consumption) of vehicles due to the lower volumetric energy content of ethanol when compared to gasoline. Here we argue that due to the increased emphasis on alternative fuels with drastically differing energy densities, vehicle efficiency should be evaluated based on energy rather than volume. When done so, we show that efficiency of existing vehicles can be affected by ethanol content, but these impacts can serve to have both positive and negative effects and are highly uncertain (ranging from -15% to +24%). As a result, uncertainties in the net GHG effect of ethanol, particularly when used in a low-level blend with gasoline, are considerably larger than previously estimated (standard deviations increase by >10% and >200% when used in high and low blends, respectively). Technical options exist to improve vehicle efficiency through smarter use of ethanol though changes to the vehicle fleets and fuel infrastructure would be required. Future biofuel policies should promote synergies between the vehicle and fuel industries in order to maximize the society-wise benefits or minimize the risks of adverse impacts of ethanol.

  View details for DOI 10.1021/es305209a

  View details for Web of Science ID 000320097400006

  View details for PubMedID 23627549

• Quantifying the uncertainties in life cycle greenhouse gas emissions for UK wheat ethanol ENVIRONMENTAL RESEARCH LETTERS Yan, X., Boies, A. M. 2013; 8 (1)

  View details for DOI 10.1088/1748-9326/8/1/015024

  View details for Web of Science ID 000316998300087

• Chemical Kinetics of Photoinduced Chemical Vapor Deposition: Silica Coating of Gas-Phase Nanoparticles JOURNAL OF PHYSICAL CHEMISTRY C Boies, A. M., Calder, S., Agarwal, P., Lei, P., Girshick, S. L. 2012; 116 (1): 104-114

  View details for DOI 10.1021/jp2071716

  View details for Web of Science ID 000298978700013

• Implications of local lifecycle analyses and low carbon fuel standard design on gasohol transportation fuels ENERGY POLICY Boies, A. M., McFarlane, D., Taff, S., Watts, W. F., Kittelson, D. B. 2011; 39 (11): 7191-7201

  View details for DOI 10.1016/j.enpol.2011.08.040

  View details for Web of Science ID 000298120200051