97 research outputs found
Developing force field parameters for water interacting with graphene and graphene-like materials
Get PDFConfined water can have properties dramatically different from bulk water, and these properties can be used to develop unique functionality at the nanoscale. For example, fast water transport, rotation-translation coupling, and fast rotationalmotion have been observed in graphitic carbon-based nano structures, which enables various applications like energy storage and seawater desalination. The explosive studies on graphene have sparked new interests towards graphene-analogous materials including hexagonal boron nitride (hBN) and molybdenum disulfide (MoS2). Compared to graphene, the graphene-analogous materials possess non-zero bandgap, chemical inertness, and biological compatibility. The graphene-analogous materials are promising materials, complementary to graphene, for high-temperature, biomedical and nanofluidic applications. We would like to understand and optimize graphene and graphene-analogous materials in these applications.
The study of graphene and graphene-analogous materials at the atomic level requires accurate force field parameters to describe the water-surface interaction. We begin with benchmark quality first principles quantum Monte Carlo (QMC) calculations on the interaction energy between water and surface, which are used to validate random phase approximation (RPA) calculations. We then proceed with RPA to derive force field parameters, which are used to simulate properties like water contact angle on the surface, attaining a value within the experimental uncertainties. This work demonstrates that end-to-end multiscale modeling, starting at detailed many-body quantum mechanics, and ending with macroscopic properties, with the approximations controlled along the way, is feasible for these systems.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-08-01The student, Yanbin Wu, accepted the attached license on 2016-07-01 at 11:25.The student, Yanbin Wu, submitted this Dissertation for approval on 2016-07-01 at 11:32.This Dissertation was approved for publication on 2016-07-05 at 09:40.DSpace SAF Submission Ingestion Package generated from Vireo submission #9740 on 2016-11-10 at 12:24:48Made available in DSpace on 2016-11-10T18:39:15Z (GMT). No. of bitstreams: 3
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A data-driven crop model for maize yield prediction
Get PDFAccurate estimation of crop yield predictions is of great importance for food security under the impact of climate change. We propose a data-driven crop model that combines the knowledge advantage of process-based modeling and the computational advantage of data-driven modeling. The proposed model tracks the daily biomass accumulation process during the maize growing season and uses daily produced biomass to estimate the final grain yield. Computational studies using crop yield, field location, genotype and corresponding environmental data were conducted in the US Corn Belt region from 1981 to 2020. The results suggest that the proposed model can achieve an accurate prediction performance with a 7.16% relative root-mean-square-error of average yield in 2020 and provide scientifically explainable results. The model also demonstrates its ability to detect and separate interactions between genotypic parameters and environmental variables. Additionally, this study demonstrates the potential value of the proposed model in helping farmers achieve higher yields by optimizing seed selection.This article is published as Chang, Yanbin, Jeremy Latham, Mark Licht, and Lizhi Wang. "A data-driven crop model for maize yield prediction." Communications Biology 6, no. 1 (2023): 439.
DOI: 10.1038/s42003-023-04833-y.
Copyright 2023 The Author(s).
Attribution 4.0 International (CC BY 4.0).
Posted with permission
Evaluation of a redox-initiated in situ hydrogel as vitreous substitute
No full textCurrently there is no material clinically available as a long-term vitreous substitute. In this study, an insitu gelation system based on alpha-poly(ethylene glycol) methacrylate (alpha-PEG-MA) and a redox-initiated radical polymerization/crosslinking reaction was evaluated for this purpose. Ammonium persulfate CAPS) and N,N,N',N'-tetramethyl ethylene diamine (TMEDA) were used as initiators. The gelation time, rheological properties, reaction kinetics and swelling profiles were studied in detail and the system with 10 wt% of alpha-PEG-MA and 8 mM APS/TMEDA was chosen as the optimal material for in vivo studies. Using the rabbit as the animal model, we showed that the system did form a space-filling and transparent gel in the vitreous cavity, and the inflammation response could be controlled to an acceptable level. (C) 2014 Elsevier Ltd. All rights reserved.Polymer ScienceSCI(E)[email protected]; [email protected]; [email protected]
Adaptive Graph Partition Methods for Structured Graphs
No full textGraphs can be models for many real-world systems, where nodes indicate the entities and edges indicate the pairwise connections in between. In various cases, it is important to detect informative subsets of nodes such that the nodes within the subsets are ’closer’ to each other. For example, in a cellular network, determining appropriate node subsets can reduce the operation costs. A subset is usually called a cluster. This leads to the graph clustering problem. Furthermore, plenty of systems in the real world are changing over time, and consequently, graphs as models vary with time as well. It is thus also important to update the clusters when the graph changes.In this thesis work, we studied two problems from the cellular network background. We needed to partition graphs that have certain structures and cluster their nodes to minimize certain cost functions. In the first problem, we partitioned a bipartite graph by minimizing the so-called MinMaxCut cost function, while in the second problem, we partitioned a structured graph by minimizing the so-called Modified-MinMaxCut cost function. The structural property of the graph is incorporated in defining this new cost function. The solutions we proposed are under the framework of spectral clustering, where one relies on the eigenvectors of the graph matrices, e.g., the Laplacian matrix or the adjacency matrix, and any clustering algorithm, e.g., K-means, to partition nodes into disjoint clusters.Furthermore, for the time-variant graph, we decomposed the problem into two steps. First, we transformed the variations in the graph topology into perturbations to the graph matrices. Then we transformed the update of the clusters into an update of the (generalized) eigenvectors of these graph matrices. We utilized matrix perturbation theory to update the generalized eigenvectors and then update the clusters. Our simulations showed that on synthetic data, the proposed method can efficiently track the eigenvectors and the clusters generated by the updated eigenvectors have almost the same cost function value as that of exact computation.Electrical Engineering | Wireless Communication and Sensin
An in situ-forming zwitterionic hydrogel as vitreous substitute
No full textZwitterionic polymers have shown ultra-low biofouling properties at surfaces and excellent biocompatibility as implant. In this study, an in situ-forming zwitterionic hydrogel was designed and evaluated, both in vitro and in vivo, as a long-term vitreous substitute. The zwitterionic polymer poly(MPDSA-co-AC) was designed as a copolymer of the sulfobetaine methacrylamide and acryloyl cystamine monomers, providing the zwitterionic components and the thiol functional groups, respectively. The in situ gelation was via the thiol-ene Michael addition reaction with alpha-PEG-MA as the crosslinker. The gelation time, rheological properties, swelling profiles, and the transparency of zwitterionic hydrogels were studied in detail. Two systems with different crosslinker concentrations were tested in a rabbit model, and the one with the thiol-ene ratio of 2 : 1 showed excellent biocompatibility in vivo, formed space-filling hydrogels and remained transparent in the vitreous cavity for the 2 month implantation period. Therefore, in situ-forming zwitterionic hydrogels represent a promising material system as a vitreous substitute and possibly for other soft tissue replacements.Materials Science, BiomaterialsSCI(E)[email protected]; [email protected]
Mechanical and microstructural dataset for Metamorphism-facilitated faulting in deforming orthopyroxene: implications for global intermediate-depth seismicity
No full textMechanical and microstructural dataset of deformation experiments in:----------------------------------------------------------------------------------------------------------------------------------------Metamorphism-facilitated faulting in deforming orthopyroxene: implications for global intermediate-depth seismicityFeng Shi a,b, 1, Yanbin Wang b, 1,2 , Jianguo Wen c, Tony Yu b, Lupei Zhu d, Taizi Huang e, Kelin Wang f, ea State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China b Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60439, USAc Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, USAd Department of Earth & Atmospheric Sciences, Saint Louis University, St. Louis, MO 63108, USAe School of Earth and Ocean Sciences, University of Victoria, Victoria, B.C., Canada f Pacific Geoscience Centre, Geological Survey of Canada, Sidney, B.C., Canada1 These authors contributed equally to the paper.2 Corresponding author: Yanbin Wang Email: [email protected] DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Energy efficient data gathering scheme for wireless sensor networks with static and mobile sinks
No full textExperimental Research on the Influence of the Equivalence Ratio and Operating Frequency on the APDE
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