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3. Influence of Local Density on Concentrated Static Load Performance of Oriented Strandboard

Author

Chen, Siguo and Knudson, Robert

Subjects
Strains and stresses -- Testing, Stress relaxation (Materials) -- Testing, Stress relieving (Materials) -- Testing, Business, Forest products industry
Abstract

Fourteen 1,220 by 2,440 by 11.1-mm commercial Oriented Strandboard (OSB) panels were X-ray scanned to obtain horizontal density matrices. Localized densities around the concentrated static load (CSL) testing points of the panels were calculated prior to the CSL test. A linear regression analysis was conducted to assess the impact of the localized density on CSL performance. The results indicated that both deflection and ultimate load were highly correlated with the local density. Deflection and ultimate load were somewhat correlated ([R.sup.2] = 0.52). The CSL deflection decreased and ultimate load increased significantly with increasing local density. The impact of local density on ultimate load was greater than on deflection. Horizontal density variation is inherent in OSB manufacturing processes, especially in the mat forming process. A number of factors, including evenness of strands in the metering bin, condition of picker rolls and dissolving rolls, and strand and fines surging, can affect horizontal density distribution. OSB panels with a high degree of variation in horizontal panel density may cause low density spots that increase the chance of failure in CSL test. It is therefore crucial to minimize the occurrence of very low density areas in order to reduce the odds of ultimate load failure. Reducing density variability allows OSB companies to increase the CSL properties of their products, which would otherwise need to be done by making the panel denser. Improving horizontal density uniformity allows for lowering of the average panel density, which reduces the manufacturing cost and helps improve the company's bottom line., Oriented Strandboard (OSB) market is growing rapidly especially since the onset of the COVID-19 pandemic. A report released in 2021 by Reportlinker.com (Globenewswire 2021) projected the global OSB market to [...]

Published
2023
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12. Locking the lattice oxygen in RuO2 to stabilize highly active Ru sites in acidic water oxidation.

Author

Ping, Xinyu, Liu, Yongduo, Zheng, Lixia, Song, Yang, Guo, Lin, Chen, Siguo, and Wei, Zidong

Abstract

Ruthenium dioxide is presently the most active catalyst for the oxygen evolution reaction (OER) in acidic media but suffers from severe Ru dissolution resulting from the high covalency of Ru-O bonds triggering lattice oxygen oxidation. Here, we report an interstitial silicon-doping strategy to stabilize the highly active Ru sites of RuO2 while suppressing lattice oxygen oxidation. The representative Si-RuO2−0.1 catalyst exhibits high activity and stability in acid with a negligible degradation rate of ~52 μV h−1 in an 800 h test and an overpotential of 226 mV at 10 mA cm−2. Differential electrochemical mass spectrometry (DEMS) results demonstrate that the lattice oxygen oxidation pathway of the Si-RuO2−0.1 was suppressed by ∼95% compared to that of commercial RuO2, which is highly responsible for the extraordinary stability. This work supplied a unique mentality to guide future developments on Ru-based oxide catalysts’ stability in an acidic environment.RuO2 is highly active toward the acidic electrochemical oxygen evolution reaction but exhibits instability due to lattice oxygen oxidation. Here, authors prepare an interstitial Si-decorated RuO2 catalyst with improved stability for acidic water oxidation by suppressing lattice oxygen oxidation. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Synergistic effect of strand angle and panel density on bending properties of strand-based wood composites

Author

Liu, Xiaohong, Chen, Siguo, and Wellwood, Robert

Subjects
Forest products -- Materials -- Properties -- Analysis, Business, Forest products industry
Abstract

Abstract The impacts of panel density and strand alignment, and their synergistic effect, on bending strength and stiffness of strand-based wood composites were investigated experimentally. Fifteen unidirectional strand panels with [...]

Published
2010

21. A new measure of strand alignment with respect to bending stiffness

Author

Chen, Siguo, Liu, Zhi-Kun, Fang, Luming, and Wellwood, Robert

Subjects
Forest products -- Testing -- Measurement, Business, Forest products industry, Testing, Measurement
Abstract

Abstract A new measure of strand alignment that effectively quantifies the bending stiffness as affected by strand angle distribution was proposed. This simplified measure combines the strand angle frequency distribution [...]

Published
2008

22. Analysis of strand characteristics and alignment of commercial OSB panels

Author

Chen, Siguo, Du, Chungui, and Wellwood, Robert

Subjects
Geometry -- Analysis, Business, Forest products industry, Analysis
Abstract

Abstract Due to the highest stresses occurring at the surfaces of a panel in bending, the alignment of strands at the surface layers is crucial to the bending strength and [...]

Published
2008

23. A three-dimensional solid model for OSB mat

Author

Li, Peng, Wang, Sunguo, Chen, Siguo, and Wang, Fenghu

Subjects
Forest products industry -- Case studies, Computer simulation -- Case studies, Computer-generated environments -- Case studies, Monte Carlo method -- Case studies, Business, Forest products industry, Case studies
Abstract

Abstract A three-dimensional solid model was developed to simulate behaviors of individual strands in the mat-forming process and to further investigate structural characteristics of an oriented strandboard (OSB) mat. Compared [...]

Published
2008

26. Towards Effective Utilization of Nitrogen-Containing Active Sites: Nitrogen-doped Carbon Layers Wrapped CNTs Electrocatalysts for Superior Oxygen Reduction

Author

Nie, Yao, Xie, Xiaohong, Chen, Siguo, Ding, Wei, Qi, Xueqiang, Wang, Yao, Wang, Jun, Li, Wei, Wei, Zidong, Shao, Minhua, Nie, Yao, Xie, Xiaohong, Chen, Siguo, Ding, Wei, Qi, Xueqiang, Wang, Yao, Wang, Jun, Li, Wei, Wei, Zidong, and Shao, Minhua

Abstract

The great challenge of designing nitrogen-doped carbon catalysts for oxygen reduction reaction (ORR) is how to reach high utilization of nitrogen-containing active sites and high electrocatalytic performance. By considering the requirements for achieving high nitrogen utilization, proper nitrogen bonding state, and sufficient electron transportation, this work developed a core-shell nanostructured CNT@NC composite with an N-containing carbon shell well-wrapped around a carbon nanotube (CNT) core based on a sacrificed template method. The easily accessible nitrogen atoms enriched on the surface, combined with the contacted CNT electron highways, render the N-containing active sites at outer shell with high ORR catalytic efficiency. © 2015 Elsevier Ltd.

Published
2016

29. The role of nitrogen sources and hydrogen adsorption on the dynamic stability of Fe-N-C catalysts in oxygen reduction reaction.

Author

Huang Z, Li F, Liu Y, Chen S, Wei Z, and Tang Q

Abstract

Fe-N-C catalysts are promising alternatives to Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in various electrochemical applications. However, their practical implementation is impeded by their instability during prolonged operation. Various degradation mechanisms have been proposed, yet the real origin of the intrinsic instability of Fe-N-C structures under ORR operations is still disputed. Herein, we observed a new type of protonation mechanism based on advanced first-principles simulations and experimental characterizations. The results revealed strong evidence of pyrrolic-N protonation in pyrrolic-type FeN 4 , which plays a vital role for the low kinetic barrier of Fe leaching. Conversely, the pyridinic-type FeN 4 prefers protonation at the Fe site, contributing to the higher barrier of Fe leaching and relatively higher stability. The facile pyrrolic-N protonation is verified by various spectroscopy characterizations in the Nafion-treated FePc molecule. Crucially, the presence of oxygen-containing intermediates at the Fe site can further work synergistically with N protonation to promote conversion of iron atoms (Fe-N 4 ) into ferric oxide under working potentials, and the more positive the electrode potential, the lower the kinetic barrier of Fe leaching. These findings serve as a foundation for future research endeavors on the stability issues of Fe-N-C catalysts and advancing their application in sustainable energy conversion technologies., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Published
2023
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