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Dobrzanski E, Ferreira ES, Tiwary P, Agrawal P, Chen R, Cranston ED. Size-structure-property relationship of wood particles in aqueous and dry insulative foams. Carbohydr Polym 2024; 335:122077. [PMID: 38616097 DOI: 10.1016/j.carbpol.2024.122077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/11/2024] [Accepted: 03/18/2024] [Indexed: 04/16/2024]
Abstract
Three size-fractionated samples of pine beetle-killed wood particles were used to prepare lightweight insulative foams. The foams were produced by foam-forming an aqueous slurry containing wood particles (125-1000 μm), a polymer binder, and surfactant, followed by oven drying. The effect of wood particle size on the aqueous foam stability, structure, and performance of insulative foams was investigated. While all aqueous foams were highly stable, aqueous foam stability increased with decreasing particle size. For dry foams, the cell size distribution was similar for all particle sizes as it was primarily controlled by the surfactant; differences occurred within the cell wall structure. A size-structure-property relationship was identified using x-ray micro-computed tomography where smaller particles produced lighter cell wall frameworks, leading to lower densities and decreased thermal conductivity and compressive strength. Larger particles produced denser cell wall frameworks that were more resistant to deformation, although all dry foams had sufficient mechanical properties for use as insulation panels. Thermal conductivity for all wood particle size-fractionated samples was <0.047 W m-1 K-1 making the foams similar to expanded polystyrene/polyurethane and supporting their use as thermal insulation in buildings.
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Affiliation(s)
- Elizabeth Dobrzanski
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bioproducts Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Elisa S Ferreira
- Bioproducts Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Wood Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP, Brazil.
| | | | | | | | - Emily D Cranston
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bioproducts Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Wood Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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Evans L, Cameron MK, Tiwary P. Computing committors via Mahalanobis diffusion maps with enhanced sampling data. J Chem Phys 2022; 157:214107. [PMID: 36511548 DOI: 10.1063/5.0122990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The study of phenomena such as protein folding and conformational changes in molecules is a central theme in chemical physics. Molecular dynamics (MD) simulation is the primary tool for the study of transition processes in biomolecules, but it is hampered by a huge timescale gap between the processes of interest and atomic vibrations that dictate the time step size. Therefore, it is imperative to combine MD simulations with other techniques in order to quantify the transition processes taking place on large timescales. In this work, the diffusion map with Mahalanobis kernel, a meshless approach for approximating the Backward Kolmogorov Operator (BKO) in collective variables, is upgraded to incorporate standard enhanced sampling techniques, such as metadynamics. The resulting algorithm, which we call the target measure Mahalanobis diffusion map (tm-mmap), is suitable for a moderate number of collective variables in which one can approximate the diffusion tensor and free energy. Imposing appropriate boundary conditions allows use of the approximated BKO to solve for the committor function and utilization of transition path theory to find the reactive current delineating the transition channels and the transition rate. The proposed algorithm, tm-mmap, is tested on the two-dimensional Moro-Cardin two-well system with position-dependent diffusion coefficient and on alanine dipeptide in two collective variables where the committor, the reactive current, and the transition rate are compared to those computed by the finite element method (FEM). Finally, tm-mmap is applied to alanine dipeptide in four collective variables where the use of finite elements is infeasible.
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Affiliation(s)
- L Evans
- Department of Mathematics, University of Maryland, College Park, Maryland 20742, USA
| | - M K Cameron
- Department of Mathematics, University of Maryland, College Park, Maryland 20742, USA
| | - P Tiwary
- Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Tiwary P, Najafi N, Kontopoulou M. Advances in peroxide‐initiated graft modification of thermoplastic biopolyesters by reactive extrusion. CAN J CHEM ENG 2021. [DOI: 10.1002/cjce.24080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Praphulla Tiwary
- Department of Chemical Engineering Queen's University Kingston Ontario Canada
| | - Naqi Najafi
- Department of Chemical Engineering Queen's University Kingston Ontario Canada
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Kushwaha A, Tiwary P, Sundar S. Blood meal identification in wild-caught sand flies from the endemic region of visceral leishmaniasis in India. Int J Infect Dis 2018. [DOI: 10.1016/j.ijid.2018.04.4089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Tiwary P, Park CB, Kontopoulou M. Transition from microcellular to nanocellular PLA foams by controlling viscosity, branching and crystallization. Eur Polym J 2017. [DOI: 10.1016/j.eurpolymj.2017.04.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tiwary P, Gui H, Ferreira PL, Kontopoulou M. Coagent Modified Polypropylene Prepared by Reactive Extrusion: A New Look into the Structure-Property Relations of Injection Molded Parts. INT POLYM PROC 2016. [DOI: 10.3139/217.3209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AbstractPeroxide-mediated reactive extrusion of linear isotactic polypropylene (L-PP) was conducted in the presence of trimethylolpropane trimethacrylate (TMPTMA) and triallyl trimesate (TAM) coagents, using a twin screw extruder. The resulting coagent-modified polypropylenes (CM-PP) had higher viscosities and elasticities, as well as increased crystallization temperature compared to PP reacted only with peroxide (DCP-PP). Additionally, deviations from terminal flow, and strain hardening were observed in PP modified with TAM, signifying the presence of long chain branching (LCB). The CM-PP formulations retained the modulus and tensile strength of the parent L-PP, in spite of their lower molar mass and viscosities, whereas their elongation at break and the impact strength were better. This was attributed to the finer spherulitic structure of these materials, and to the disappearance of the skin-core layer in the injection molded specimens.
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Affiliation(s)
- P. Tiwary
- 1Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada
| | - H. Gui
- 2Sinopec, Beijing Research Institute of Chemical Industry, Beijing, PRC
| | - P. L. Ferreira
- 1Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada
| | - M. Kontopoulou
- 1Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada
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Padekar D, Bhattacharyya T, Ray SK, Tiwary P, Chandran P. Influence of Irrigation Water on Black Soils in Amravati District, Maharashtra. CURR SCI INDIA 2016. [DOI: 10.18520/cs/v110/i9/1740-1755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kumar D, Tiwary P, Chakravarty J, Sundar S. Association of interleukin-18 gene polymorphism with susceptibility to visceral leishmaniasis in endemic area of Bihar, an Indian population. Int J Infect Dis 2016. [DOI: 10.1016/j.ijid.2016.02.783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Tiwary P, Kumar D, Sundar S. Identification and functional validation of a biomarker for the diagnosis of miltefosine relapse during visceral leishmaniasis. Int J Infect Dis 2016. [DOI: 10.1016/j.ijid.2016.02.210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Bhattacharyya T, Wani SP, Chandran P, Tiwary P, Pal DK, Sahrawat KL, Velayutham M. Soil Information System: Web-Based Solution for Agricultural Land-use Planning. CURR SCI INDIA 2016. [DOI: 10.18520/cs/v110/i2/241-250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Zhang Y, Tiwary P, Gui H, Kontopoulou M, Parent JS. Crystallization of Coagent-Modified Polypropylene: Effect of Polymer Architecture and Cross-Linked Nanoparticles. Ind Eng Chem Res 2014. [DOI: 10.1021/ie5027277] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ying Zhang
- Department
of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Praphulla Tiwary
- Department
of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Hua Gui
- Department
of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Marianna Kontopoulou
- Department
of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - J. Scott Parent
- Department
of Chemical Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
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Bhattacharyya T, Pal D, Ray S, Chandran P, Mandal C, Telpande B, Deshmukh A, Tiwary P. Simulating change in soil organic carbon in two long term fertilizer experiments in India: with the RothCmodel. ACTA ACUST UNITED AC 2013. [DOI: 10.5958/j.2320-642x.1.2.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pandey D, Tiwary P. Diffuse scattering from stacking faults: scaling of pair correlation function. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311098114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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