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Anthropogenic, biogenic, and photochemical influences on surface formaldehyde and its significant decadal (2006–2017) decrease in the Lewiston-Clarkston valley of the northwestern United States

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Chemosphere 2024年 349卷 140962页

作者： Li, R. Jobson, B.T. Wen, M. Li, A.L. Huangfu, Y. Zhang, W. Hardy, R. Simpson, J. Fauci, M. Paden, N. Idaho Department of Environmental Quality Boise ID United States Laboratory for Atmospheric Research Department of Civil & Environmental Engineering Washington State University Pullman WA United States Boise High School Boise ID United States Air Quality Program Nez Perce Tribe Lapwai ID United States

Formaldehyde (HCHO) is a key carcinogen and plays an important role in atmospheric chemistry. Both field measurements and Positive Matrix Factorization (PMF) modeling have been employed to investigate the concentrations and sources of HCHO in the Lewiston-Clarkston (LC) valley of the mountainous northwestern U.S. Different instruments were deployed to measure surface formaldehyde and other related compounds in July of 2016 and 2017. The measurements reveal that the average HCHO concentrations have significantly decreased to 2–5 ppb in the LC valley in comparison to its levels (10–20 ppb) observed in July 2006. This discovery with surface measurements deserves attention given that satellite retrievals showed an increasing long-term trend from 2005 to 2014 in total vertical column density of HCHO in the region, suggesting that satellite instruments may not adequately resolve small valleys in the mountainous region. Our PMF modeling identified four major sources of HCHO in the valley: (1) emissions from a local paper mill, (2) secondary formation and background, (3) biogenic sources, and (4) traffic. This study reveals that the emissions from the paper mill cause high HCHO spikes (6–19 ppb) in the early morning. It is found that biogenic volatile organic compounds (VOCs) in the area are influenced by national forests surrounding the region (e.g., Nez Perce-Clearwater, Umatilla, Wallowa-Whitman, and Idaho Panhandle National Forests). The results provide useful information for developing strategies to control HCHO levels and have implications for future HCHO studies in atmospheric chemistry, which affects secondary aerosols and ozone formation. © 2023 Elsevier Ltd

关键词： Biogenic VOCs Field measurements Formaldehyde (HCHO) sources Long-term surface HCHO trend Secondary formation Source apportionment

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A Dynamic Model of a Skydiver With Validation in Wind Tunnel and Free Fall

arXiv

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arXiv 2022年

作者： Clarke, Anna Gutman, Per-Olof Technion Autonomous Systems Program Technion - Israel Institute of Technology Haifa32000 Israel Faculty of Civil and Environmental Engineering Technion - Israel Institute of Technology Haifa32000 Israel

An innovative approach of gaining insight into motor skills involved in human body flight is proposed. The key idea is the creation of a model autonomous system capable of virtually performing skydiving maneuvers. A dynamic skydiver model and simulator is developed, comprising biomechanical, aerodynamic, and kinematic models, dynamic equations of motion, and a virtual reality environment. Limb relative orientations, and resulting inertial body angular position and velocity are measured in skydiving experiments in a vertical wind tunnel and in free fall. These experimental data are compared with corresponding simulation data to tune and verify the model for basic skydiving maneuvers. The model is further extended to reconstruct advanced aerial maneuvers, such as transitions between stable equilibria. The experimental data are used to estimate skydiver’s conscious inputs as a function of time, via an Unscented Kalman Filter modified for this purpose. © 2022, CC BY.

关键词： Biomechanics

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An Automatic Control System with Human-in-the-Loop for Training Skydiving Maneuvers: Proof-of-Concept Experiment

arXiv

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arXiv 2022年

A real-time motion training system for skydiving is proposed. Aerial maneuvers are performed by changing the body posture and thus deflecting the surrounding airflow. The natural learning process is extremely slow due to unfamiliar free-fall dynamics, stress induced blocking of kinesthetic feedback, and complexity of the required movements. The key idea is to augment the learner with an automatic control system that would be able to perform the trained activity if it had direct access to the learner’s body as an actuator. The aiding system will supply the following visual cues to the learner: 1. Feedback of the current body posture;2. The body posture that would bring the body to perform the desired maneuver;3. Prediction of the future inertial position and orientation if the body retains its present posture. The system will enable novices to maintain stability in free-fall and perceive the unfamiliar environmental dynamics, thus accelerating the initial stages of skill acquisition. This paper presents results of a Proof-of-Concept experiment, whereby humans controlled a virtual skydiver free-falling in a computer simulation, by the means of their bodies. This task was impossible without the aiding system, enabling all participants to complete the task at the first attempt. © 2022, CC BY.

关键词： Learning systems

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Incorporating Prior Knowledge into Neural Networks through an Implicit Composite Kernel

arXiv

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arXiv 2022年

作者： Jiang, Ziyang Zheng, Tongshu Liu, Yiling Carlson, David Department of Civil and Environmental Engineering Duke University United States Division of Natural and Applied Science Duke Kunshan University China Program in Computational Biology and Bioinformatics Duke University School of Medicine United States Department of Civil and Environmental Engineering Department of Biostatistics and Bioinformatics Department of Computer Science Duke University United States

It is challenging to guide neural network (NN) learning with prior knowledge. In contrast, many known properties, such as spatial smoothness or seasonality, are straightforward to model by choosing an appropriate kernel in a Gaussian process (GP). Many deep learning applications could be enhanced by modeling such known properties. For example, convolutional neural networks (CNNs) are frequently used in remote sensing, which is subject to strong seasonal effects. We propose to blend the strengths of NNs and the clear modeling capabilities of GPs by using a composite kernel that combines a kernel implicitly defined by a neural network with a second kernel function chosen to model known properties (e.g., seasonality). We implement this idea by combining a deep network and an efficient mapping function based on either Nyström approximation or random Fourier features, which we call Implicit Composite Kernel (ICK). We then adopt a sample-then-optimize approach to approximate the full GP posterior distribution. We demonstrate that ICK has superior performance and flexibility on both synthetic and real-world datasets including a remote sensing dataset. The ICK framework can be used to include prior information into neural networks in many applications. © 2022, CC BY.

关键词： Remote sensing

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Relative extents, mechanisms, and kinetics of fluoride removal from synthetic groundwater by prevalent sorbents

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Chemosphere 2023年 342卷 140161页

作者： Ekamparam, Aravinth Siva Subramaniam Khaitan, Harshit Nimesh, Vishakha Singh, Abhas Department of Civil Engineering Indian Institute of Technology Kanpur Uttar Pradesh 208 016 India Environmental Geochemistry Laboratory Centre for Environmental Science and Engineering Indian Institute of Technology Kanpur Uttar Pradesh 208 016 India Department of Biological & Ecological Engineering Oregon State University CorvallisOR97331 United States Google India Telangana Hyderabad500 081 India Environmental Engineering and Management Program Indian Institute of Technology Kanpur Uttar Pradesh 208 016 India Department of Environment Management Systems East Delhi Municipal Corporation Government of Delhi New Delhi110 096 India

Fluoride (F) contamination in groundwater affects millions of people across the world. Although several sorbents have been identified for low-cost F removal, the choice of the optimal sorbent is dictated by the specific chemistry of contaminated groundwater. In this contribution, eight prevalent sorbents—activated alumina (AA), calcite, hydroxyapatite-coated calcite (HCC), natural chitosan, chalk, Mg–Al–CO3 layered double hydroxide (LDH), calcined Mg–Al–CO3 LDH (cLDH), and hydrous ferric oxide (HFO)—were categorized on their relative F removal mechanisms, extents, and kinetics from a typical synthetic groundwater, representative of contaminated aquifers of North India. Initially, batch experiments containing sorbents at 4 g·L−1 were conducted at a high F concentration (2.9 mM). The dominant F removal processes were identified by aqueous- and solid-phase characterization of reaction by-products. While chalk and calcite removed F by secondary precipitation of fluorite, HCC removed F by fluorapatite precipitation, and other sorbents removed F by sorption. Depending on the immobilization mechanism identified, the F uptake kinetics on each sorbent was modeled with either pseudo-second order or generalized rate equations. Among sorptive F uptake, cLDH exhibited the highest (10−2.15 mg·g−1·h−1) and HFO showed the lowest (10−4.15 mg·g−1·h−1) rates. Fluoride removal by precipitation was the fastest with chalk at 10−1.3 (h−1) (0.16). Subsequent experiments with AA and HCC at lower initial F concentration (0.42 mM) suggested increased uptake by ∼30x and ∼7x, respectively, relative to uptake in 2.9 mM initial F systems. For AA, apart from the widely-accepted mechanism of adsorption, an unidentified F-containing surface precipitate was formed. HCC was identified as the most promising sorbent with no sludge generation. © 2023 Elsevier Ltd

关键词： Sorbents

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Polyolefin-derived substrate-grown carbon nanotubes as binder-free electrode for hydrogen evolution in alkaline media

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Chemosphere 2024年 349卷 140769页

作者： Wu, XinYi Tu, Wei Han Veksha, Andrei Chen, Wenqian Lisak, Grzegorz Nanyang Environment & Water Research Institute Nanyang Technological University 1 Cleantech Loop Clean Tech One 637141 Singapore School of Civil and Environmental Engineering Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Interdisciplinary Graduate Program Nanyang Technological University 1 Cleantech Loop Cleantech One Singapore 637141 Singapore

Switching from a linear mode of waste management to a circular loop by transforming plastic waste into carbon nanotubes (CNTs) is a promising approach to current plastic waste treatment. One of the many applications of CNTs is its use for electrocatalytic water splitting for hydrogen evolution. Existing methods of CNTs-based hydrogen evolution reaction (HER) electrode fabrication involve additives like polymeric binders and additional steps to improve CNT dispersion, which are detrimental to the CNT structure and properties. The in-situ fabrication approach can potentially be a one-pot solution to HER electrode synthesis. In this study, polyolefins pyrolysis gas and a Co:Ni:Mg catalyst were used to fabricate binder-free CNTs-based electrodes on different substrates for HER. The study assessed CNT quality on conductive carbon paper, semiconductive silicon, and dielectric glass substrates, evaluating their HER performance in 1 M KOH. A mixture of hollow-core, bamboo-like, and cup-stacked arrangement nanotubes were synthesized on the substrates, with CNTs on glass and carbon paper substrates possessing better graphitization than CNTs grown on silicon. This is in agreement with HER performance, whereby the as-prepared electrodes required overpotentials of 267 mV, 241 mV, and 216 mV for silicon, glass, and carbon paper, respectively, to achieve 10 mA/cm2. Despite being poorly conductive, the glass substrate electrode achieved a lower overpotential than the silicon electrode. Additionally, the as-prepared silicon electrode faced a delamination issue likely attributed to the lower surface energy of the silicon substrate surface, demonstrating the weaker adhesion between the CNTs and silicon surface. The proposed approach thus showed that the in-situ fabricated electrodes performed better than separately synthesized CNTs prepared into electrodes by 27.4% and 14.2% for carbon paper and glass substrates, respectively. The improved performance of the as-prepared, binder-free e

关键词： Carbon nanotubes

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Assessment of solar-assisted electrooxidation of bisphenol AF and bisphenol A on boron-doped diamond electrodes

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environmental Science and Ecotechnology 2020年第3期3卷 23-31页

作者： Jing Ding Lingjun Bu Bingxin Cui Guanshu Zhao Qingwei Gao Liangliang Wei Qingliang Zhao Dionysios D.Dionysiou State Key Laboratory of Urban Water Resources and Environment(SKLUWRE) School of EnvironmentHarbin Institute of TechnologyHarbin150090China Department of Water Engineering and Science College of Civil EngineeringHunan UniversityChangsha410082China Environmental Engineering and Science Program Department of Chemical and Environmental EngineeringUniversity of CincinnatiCincinnatiOH45221USA

Bisphenol(BP)analogues in wastewater effluent and groundwater pose a potential threat to human health due to their ability to disrupt steroidogenesis.A new solar-assisted electrochemical process(SECP)was developed and evaluated for the degradation of BP *** effects of quenchers,current density,initial pH,supporting electrolyte,and aqueous matrix on the removal kinetics of bisphenol AF(BPAF)and bisphenol A(BPA)were *** kinetic constants of BPAF,BPA,and bisphenol S(BPS)in the SECP with irradiation intensity of 500 mW cm^(-2) were 0.017±0.002 min^(-1),0.022±0.002 min^(-1),and 0.012±0.001 min^(-1),*** changes in the degradation rates of BPAF,BPA,and BPS in the presence of quenchers indicated the relative contribution of hydroxyl radical(·OH)oxidation,anodic electrolysis,and singlet(^(1)O_(2))oxygenation in the degradation of BPs in the *** enhanced rate of generation of ·OH and ^(1)O_(2) was observed in the SECP compared with those in the conventional electrochemical *** identification of the transformation products(TPs)of BPAF demonstrated that hydroxylation,ring cleavage,b-scission,and defluorination were the major processes during the oxidation in the *** conversion to fluoride ions(76%)and mineralization of total organic carbon(72%)in the SECP indicated further degradation of *** results from this study improved our understanding of the degradation of BP analogues in the electrooxidation irradiated by solar light and help to establish the application potential of the SECP for the effective degradation of emerging contaminants in wastewater.

关键词： Electrochemical process Solar Radicals Bisphenol AF Wastewater treatment

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Air stripping pre-treatment process to enhance biogas production in anaerobic digestion of chicken manure wastewater

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Bioresource Technology Reports 2021年 14卷

作者： Fakkaew, Krailak Polprasert, Chongrak Environmental Health Program School of Health Science Mae Fah Luang University Thailand Department of Civil Engineering Faculty of Engineering Thammasat University Thailand

Anaerobic digestion is typically applied for water and air pollution control and energy recovery from chicken manure wastewater. Unfortunately, high nitrogen content of the chicken manure could be prohibitive to efficient anaerobic digestion. In this study, air stripping was employed as a pre-treatment process for ammonia removal from a chicken manure wastewater. Laboratory-scale experiments of air striping were conducted at various temperatures, initial pH values, air flow rates, and stripping times. The experimental results showed that the high ammonia removal efficiencies of more than 80% could be achieved from the air stripping process operating at the initial pH, temperature, and air flow rate of 11, 80 °C, and 4.0 L/min, respectively. The ammonia removal kinetics were found to fit with the first-order reaction. Bio-methane potential tests suggested that air stripping pre-treatment of the chicken manure wastewater resulted in about 25% increase in biogas production. © 2021 Elsevier Ltd

关键词： Ammonia

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Harnessing High-Level Hydrogen Sulfide Stress for Enhanced Biogas Utilization: Adaptive Resilience of a Mixed-Culture System

SSRN

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SSRN 2024年

作者： Zhou, Yan Zhang, Baorui Liu, Jianbo Cai, Chen Interdisciplinary Graduate Program Nanyang Technological University 61 Nanyang Drive 637335 Singapore Nanyang Environment & Water Research Institute Nanyang Technological University 1 Cleantech Loop Singapore637141 Singapore CAS Key Laboratory of Urban Pollutant Conversion Department of Environmental Science and Engineering University of Science and Technology of China Hefei China School of Civil and Environmental Engineering Nanyang Technological University 50 Nanyang Avenue Singapore639798 Singapore

Biogas, a heterogeneous mixture predominantly composed of methane (CH4) and carbon dioxide (CO2), serves as a substrate for diverse microorganisms, including methanotrophs and microalgae, facilitating carbon sequestration, mitigating greenhouse gas emissions, and generating biomass for multifarious applications. However, the presence of hydrogen sulfide (H2S), a common contaminant in biogas, can exert toxic effects on these microorganisms, potentially inhibiting their growth and metabolic processes. This study investigated the effects of H2S on a mixed-culture system utilizing a long-term continuous flow photobioreactor. The results demonstrated that the mixed-culture system could tolerate H2S concentration up to 1000 ppm without significant performance deterioration. Notably, when the mixed-culture system was exposed to a higher H2S concentration (5000 ppm) for an extended period of one month, the CH4 and CO2 utilization rates increased threefold. Furthermore, the primary byproduct, protein, constituted over 50% of the cell dry weight. Comprehensive analysis of the microbial community composition and metabolic pathways revealed adaptive shifts in response to H2S stress. In-depth analysis of functional genes indicated that the system possessed the capacity to adapt and maintain its functionality even under severe H2S stress. This study provides valuable insights into microbial and metabolic mechanisms underlying H2S resistance in a mixed culture, providing an opportunity for the establishment of an H2S-resistant biosystem for practical biogas transformation. © 2024, The Authors. All rights reserved.

关键词： Hydrogen sulfide

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Measuring Consumer Willingness to Enroll in Battery Electric Vehicle Smart Charging programs

Measuring Consumer Willingness to Enroll in Battery Electric...

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IEEE Conference on Vehicle Power and Propulsion (VPPC)

作者： Pingfan Hu Brian Tarroja Matthew Dean Kate Forrest Eric Hittinger Alan Jenn John Paul Helveston Department of Engineering Management and Systems Engineering George Washington University Washington DC USA Department of Civil and Environmental Engineering University of California Irvine Irvine CA USA Advanced Power and Energy Program University of California Irvine Irvine CA USA Department of Public Policy Rochester Institute of Technology Rochester NY USA Institute of Transportation Studies University of California Davis Davis CA USA

ISBN: (数字)9798331541606

ISBN: (纸本)9798331541613

As Battery Electric Vehicles (BEVs) gain popularity, managing their charging becomes crucial for grid stability. Smart charging programs can help utilities manage this demand and integrate more renewable energy by controlling when and how BEVs are charged. However, these programs require participation from BEV owners, who may be hesitant to freely provide such control. This study uses a discrete choice experiment (also called conjoint analysis) to measure BEV owners' willingness to participate in smart charging programs under various incentives and features. We examine two types of smart charging: Supplier-Managed Charging (SMC), which controls charging times, and Vehicle-to-Grid (V2G), allowing BEVs to return power to the grid. In an online survey conducted via Facebook and Instagram ads, we collected 858 valid responses, with 815 responses for SMC program choices and 414 for V2G program choices. We used mixed logit (MXL) models to quantify respondents' willingness to participate. The findings indicate a general reluctance to participate in both programs without some form of incentive, with respondents being most sensitive to recurring monetary incentives. For SMC, there is also concern about ensuring sufficient battery levels in the mornings. Simulations were conducted to predict enrollment rates based on different program features. Additional data will be collected to refine the models in the coming months.

关键词： Surveys Vehicle-to-grid Renewable energy sources Analytical models Power system stability Data models Stability analysis Batteries Web sites Smart charging

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