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Effects of air-sea drag coefficient on estimating wind stress using wind statistics

Myrhaug Dag, Wang Hong, Holmedal Lars Erik, Leira Bernt J.

Oceanologia

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2022

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No. 64 (3)

546--552

EN

This article addresses the effects of the air-sea drag coefficient on estimation of wind stress based on wind statistics. This is achieved by applying the same wind stress parameterizations chosen by Wrobel-Niedzwiecka et al. (2019) together with mean wind speed statistics from three locations in the North Atlantic and one location in the Northern North Sea. The expected values and the variances of the wind stress are provided. This study is complementary to that of Wrobel-Niedzwiecka et al. (2019), also demonstrating different results depending on the drag coefficient formula used.

2

Influence of bonding condition on mechanical performance of synthetic sports surfaces by FEM

Wang Hong, Zheng Weitao, Liu Gan, Guo Zhihao, Han Rui, Li Duo

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 4

637--647

EN

The purpose of the study was to evaluate the effect of interlayer bonding conditions on the mechanical performance of a synthetic sports track with time. A two-dimensional finite element model of the synthetic sports track was developed in order to calculate the track temperature stress and strain in thermal environmental conditions. Thermal and structural responses of the multi-layer sports ground were simulated using a transient thermal and structural analysis in one day. Based on that, different physical parameters of the interlayer were considered to analyze the influence of the bonding layer status on the potential damage of the surface layer in the sports track. The results indicated that different bonding conditions would affect the strain difference between the top and bottom of the synthetic sports layer, which might cause a weak mechanical performance of the synthetic sports layer. Finally, 2D finite element analysis was regarded to be a proper tool to simulate the transient thermal and mechanical behavior of the synthetic sports track. The suggested simulation model can predict the influence of bonding conditions on damage of the synthetic sports track, which can provide some guidance for engineers and technicians working on constructions of synthetic sports tracks.

3

Tubular biofilter treatment of isobutanol emissions under various organic loading rates

Chen Hong, Peng Liang, Wei Yanxiao, Yu Lie, Jiang Bo, Wang Hong, Yu Guanlong, Zhang Guijin

Environment Protection Engineering

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2020

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Vol. 46, nr 1

15--29

EN

Isobutanol in waste gas streams was treated by a tubular biofilter (TBF) which continuously operated for 364 days under various organic loading rate (OLR) from 11 g·m–3·h–1 to 66 g·m–3·h–1. Results show that within 60 days, the TBF successfully started up even after changing the OLR from 31.3 to 15.6 g·m–3·h–1. The average removal efficiencies (REs) were totally higher than 90% when OLRs ranged from 12.14 to 66.45 g·m–3·h–1. Two distinct performance deterioration periods were observed at days 186–253 and days 280–334, both of which recovered without additional measurement. During these periods, the larvae and adult moth flies, been identified as Psychodinae infested the TBF, greatly affected the TBF performance. When the number of adult Psychodinae decreased, TBF performance recovered. The elimination capacity (EC) was 60.42 g·m–3·h–1 at the inlet OLR of 66.45 g·m–3·h–1, with the critical EC being around 50 g·m–3·h–1. Even under a low gas empty bed residence time of 15 s, the preferable REs and ECs under middle or low OLRs were still obtained by the TBF.

4

Addendum to “Stokes transport in layers in the water column based on long-term wind statistics : assessment using long-term wave statistics”

Myrhaug Dag, Wang Hong, Holmedal Lars Erik

Oceanologia

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2019

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No. 61 (4)

522--526

EN

This article addresses the Stokes drift in layers in the water column for deep water random waves based on wave statistics in terms of the sea state wave parameters significant wave height and mean zero-crossing wave period. This is exemplified by using long-term wave statistics from the North Atlantic, and is supplementary to Myrhaug et al. (2018) presenting similar results based on long-term wind statistics from the same ocean area. Overall, it appears that the results based on long-term wave statistics and long-term wind statistics are consistent. The simple analytical tool provided here is useful for estimating the wave-induced drift in layers in the water column relevant for the assessment of the transport of, for example, marine litter in the ocean based on, for example, global wave statistics.