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5. Elastically-isotropic open-cell minimal surface shell lattices with superior stiffness via variable thickness design

Author

Ma, Qingping, Zhang, Lei, Ding, Junhao, Qu, Shuo, Fu, Jin, Zhou, Mingdong, Fu, Ming Wang, Song, Xu, and Wang, Michael Yu

Subjects
Mathematics - Numerical Analysis
Abstract

Triply periodic minimal surface (TPMS) shell lattices are attracting increasingly attention due to their unique combination of geometric and mechanical properties, and their open-cell topology. However, uniform thickness TPMS shell lattices are usually anisotropic in stiffness, namely having different Young's moduli along different lattice directions. To reduce the elastic anisotropy, we propose a family of variable thickness TPMS shell lattices with isotropic stiffness designed by a strain energy-based optimization algorithm. The optimization results show that all the six selected types of TPMS lattices can be made to achieve isotropic stiffness by varying the shell thickness, among which N14 can maintain over 90% of the Hashin-Shtrikman upper bound of bulk modulus. All the optimized shell lattices exhibit superior stiffness properties and significantly outperform elastically-isotropic truss lattices of equal relative densities. Both uniform and optimized types of N14 shell lattices along [100], [110] and [111] directions are fabricated by the micro laser powder bed fusion techniques with stainless steel 316L and tested under quasi-static compression loads. Experimental results show that the elastic anisotropy of the optimized N14 lattices is reduced compared to that of the uniform ones. Large deformation compression results reveal different failure deformation behaviors along different directions. The [100] direction shows a layer-by-layer plastic buckling failure mode, while the failures along [110] and [111] directions are related to the shear deformation. The optimized N14 lattices possess a reduced anisotropy of plateau stresses and can even attain nearly isotropic energy absorption capacity., Comment: 16 figures, 6 tables, 59 references

Published
2021
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8. New insights into understanding urban traffic emissions using novel mobile air quality measurements in the Breathe London pilot study

Author

Ma, Qingping, Jones, Roderic, and Martin, Nick

Subjects
air, quality, atmospheric, chemistry, pollution, mobile, sensor
Abstract

This thesis reports an investigation into the use of mobile air quality measurements to better understand urban traffic emissions. As part of the Breathe London project, two Google Street View Cars (based at the National Physical Laboratory) were fitted with air quality monitoring instrumentation and were driven across London over approximately a one year period. These mobile laboratories used a range of reference standard techniques to measure particulate matter and pollutant gases nitric oxide (NO), nitrogen dioxide (NO₂), ozone (O₃). Carbon dioxide (CO₂) was also measured as an atmospheric tracer linked to vehicle and other combustion related emissions. The investigation begins with a characterisation and performance evaluation of the instrumentation, progressing to the development and deployment of advanced source apportionment techniques (scale separation and emission ratios) to extract the maximum information from the dataset. This study collected size-speciated particulate measurements using a light scattering device, black carbon using an aetholometer and Lung Deposited Surface Area (LDSA) using a diffusion-charging instrument. The performance of the instruments was compared using the mobile dataset. Significant amounts of close-to-source pollution were effectively measured using black carbon and LDSA (diffusion-charging) measurements. However, it was found that light scattering based particle counters were unable to measure significant amounts of pollution when measuring close to certain tailpipe emission sources. Techniques to differentiate between local emissions and a well mixed background from time series measurement signals were compared as part of the development of techniques to extract emission ratios. Whilst two distinct distributions (a low distribution for the petrol fleet compared to a higher distribution for the diesel fleet) may have been expected in the NOx emission ratio, consistently only a single distribution was seen. A time series simulation showed that the ability to resolve two separate (petrol and diesel) distributions in the emission ratio distribution was lost with increasing fleet density, due to atmospheric mixing. Emission ratios calculated with mobile data showed downward trends in NOx, black carbon and LDSA over the sampling campaign period.

Published
2021
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16. Imperfection‐Enabled Strengthening of Ultra‐Lightweight Lattice Materials.

Author

Ding, Junhao, Ma, Qingping, Li, Xinwei, Zhang, Lei, Yang, Hang, Qu, Shuo, Wang, Michael Yu, Zhai, Wei, Gao, Huajian, and Song, Xu

Abstract

Lattice materials are an emerging family of advanced engineering materials with unique advantages for lightweight applications. However, the mechanical behaviors of lattice materials at ultra‐low relative densities are still not well understood, and this severely limits their lightweighting potential. Here, a high‐precision micro‐laser powder bed fusion technique is dveloped that enables the fabrication of metallic lattices with a relative density range much wider than existing studies. This technique allows to confirm that cubic lattices in compression undergo a yielding‐to‐buckling failure mode transition at low relative densities, and this transition fundamentally changes the usual strength ranking from plate > shell > truss at high relative densities to shell > plate > truss or shell > truss > plate at low relative densities. More importantly, it is shown that increasing bending energy ratio in the lattice through imperfections such as slightly‐corrugated geometries can significantly enhance the stability and strength of lattice materials at ultra‐low relative densities. This counterintuitive result suggests a new way for designing ultra‐lightweight lattice materials at ultra‐low relative densities. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Association of late-life blood pressure change with cerebral small vessel disease in the MIND-China study.

Author

Lu, Wei, Ma, Qingping, Wang, Jiafeng, Li, Chunyan, Xie, Qianqian, Chen, Ziwei, Zhang, Huisi, Song, Lin, and Du, Yifeng

Subjects
CEREBRAL small vessel diseases, BLOOD pressure, MAGNETIC resonance imaging, BULLOUS pemphigoid, LACUNAR stroke, BASAL ganglia
Abstract

Objectives: This study aimed to investigate the associations between changes in blood pressure (BP) and cerebral small vessel disease (CSVD). Methods: This study included 401 participants in the magnetic resonance imaging (MRI) sub-study conducted between 2018 and 2020 as a part of the Multidomain Interventions to Delay Dementia and Disability in Rural China project. MRI markers of CSVD were assessed based on international criteria. Individualized linear regression models evaluated changes in BP by estimating the trend of blood pressure changes over time and fitting a straight line from 2014 to 2018. The data were analyzed using logistic and general linear regression models. Result: The mean age of the participants was 64.48 ± 2.69 years, with 237 (59.1%) being females. Increases in systolic BP in later life were significantly associated with larger volumes of periventricular white matter hyperintensity (WMH), greater perivascular spaces in the basal ganglia (BG-PVS) burden, and the presence of deep lacunes and cerebral microbleeds. Additionally, increases in diastolic BP in later life were significantly associated with the presence of infratentorial and deep lacunes. Conclusions: CSVDs are associated with increased exposure to elevated BP later in life. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Natural Alkaloid Waltherione F-Derived Hydrazide Compounds Evaluated in an Agricultural Fungicidal Field

Author

Chen, Zhanfang, primary, Fang, Hongbin, additional, Chang, Jing, additional, Zhang, Tiancheng, additional, Cui, Yanhong, additional, Zhang, Lingxiao, additional, Sui, Junkang, additional, Ma, Qingping, additional, Su, Peisen, additional, Wang, Juyuan, additional, Ru, Jing, additional, Gu, Yucheng, additional, Zhang, Hengjia, additional, and Hua, Xuewen, additional

Published
2023
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37. Red and Blue Light Affect the Formation of Adventitious Roots of Tea Cuttings (Camellia sinensis) by Regulating Hormone Synthesis and Signal Transduction Pathways of Mature Leaves

Author

Shen, Yaozong, Fan, Kai, Wang, Yu, Wang, Hui, Ding, Shibo, Song, Dapeng, Shen, Jiazhi, Li, He, Song, Yujie, Han, Xiao, Qian, Wenjun, Ma, Qingping, and Ding, Zhaotang

Subjects
Plant Science
Abstract

Light is an important environmental factor which affects plant growth, through changes of intensity and quality. In this study, monochromatic white (control), red (660 nm), and blue (430 nm) light-emitting diodes (LEDs) were used to treat tea short cuttings. The results showed the most adventitious roots in blue light treated tea cuttings, but the lowest roots in that treated by red light. In order to explore the molecular mechanism of light quality affecting adventitious root formation, we performed full-length transcriptome and metabolome analyses of mature leaves under three light qualities, and then conducted weighted gene co-expression network analysis (WGCNA). Phytohormone analysis showed that Indole-3-carboxylic acid (ICA), Abscisic acid (ABA), ABA-glucosyl ester (ABA-GE), trans-Zeatin (tZ), and Jasmonic acid (JA) contents in mature leaves under blue light were significantly higher than those under white and red light. A crosstalk regulatory network comprising 23 co-expression modules was successfully constructed. Among them, the “MEblue” module which had a highly positive correlation with ICA (R = 0.92, P = 4e-04). KEGG analysis showed that related genes were significantly enriched in the “Plant hormone signal transduction (ko04075)” pathway. YUC (a flavin-containing monooxygenase), AUX1, AUX/IAA, and ARF were identified as hub genes, and gene expression analysis showed that the expression levels of these hub genes under blue light were higher than those under white and red light. In addition, we also identified 6 auxin transport-related genes, including PIN1, PIN3, PIN4, PILS5, PILS6, and PILS7. Except PILS5, all of these genes showed the highest expression level under blue light. In conclusion, this study elucidated the molecular mechanism of light quality regulating adventitious root formation of tea short cutting through WGCNA analysis, which provided an innovation for “rapid seedling” of tea plants.

Published
2022

39. Remodelling of the tumour-lymph node immune microenvironment promotes T- and NK-cell comobilization for tumour immunotherapy

Author

Fu, Shunli, primary, Chang, Lili, additional, Liu, Shujun, additional, Gao, Tong, additional, Xiao, Sang, additional, Zhang, Zipeng, additional, Mu, Weiwei, additional, Liu, Xiaoqing, additional, Liang, Shuang, additional, Yang, Han, additional, Yang, Huizhen, additional, Ma, Qingping, additional, Liu, Yongjun, additional, and Zhang, Na, additional

Published
2022
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43. Elastically-isotropic open-cell mechanical metamaterials : design, analysis, fabrication and experiments

Author

Wang, Michael Yu, Ma, Qingping, Wang, Michael Yu, and Ma, Qingping

Abstract

Mechanical metamaterials are artificial structures whose mechanical properties are determined by the downscale micro-architectures and can be made to achieve unconventional mechanical properties through appropriate design of the architectures. The elastically-isotropic open-cell mechanical metamaterials are attracting increasingly attention for the identical stiffness properties along all directions and the open-cell topology to facilitate the additive manufacturing through easier removal of resins or metal powders, thus making them ideal candidates in a variety of fields where the primary loading direction is unknown and a considerable mass and heat transfer is required. In this thesis, two classes of elastically-isotropic open-cell mechanical metamaterials are proposed, including the elastically-isotropic truss lattices and shell lattices, which are all shown to possess superior mechanical properties and therefore have a wide range of application prospects. First, a family of elastically-isotropic truss lattices are proposed via compositions of elementary cubic symmetric truss lattices with contrary elastic anisotropy, which are all shown to undergo stretching-dominated deformations under arbitrary loading conditions through matrix analysis of the static and kinematic determinacies. The stiffness properties of the combined lattices are first analytically shown to reach the upper bounds for elastically-isotropic truss lattices, which are nearly 1/3 of the Hashin-Shtrikman (HS) upper bounds in low relative densities, and then further validated by the strain energy-based numerical homogenization procedure. Further comparisons between the stiffness properties of the combined lattices with the relative densities of 10% and 1% reveal that those with lower relative densities possess closer stiffness properties to the theoretical values due to their lower bending effects and higher stretching to bending stiffness ratio. Then, a family of elastically-isotropic open-cell va

Published
2021

46. Integrated Application of Rapeseed Cake and Green Manure Enhances Soil Nutrients and Microbial Communities in Tea Garden Soil

Author

Fu, Haiping, primary, Li, Huan, additional, Yin, Peng, additional, Mei, Huiling, additional, Li, Jianjie, additional, Zhou, Pinqian, additional, Wang, Yuanjiang, additional, Ma, Qingping, additional, Jeyaraj, Anburaj, additional, Thangaraj, Kuberan, additional, Chen, Xuan, additional, Li, Xinghui, additional, and Guo, Guiyi, additional

Published
2021
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49. Untargeted metabolomic analysis using UPLC-MS/MS identifies metabolites involved in shoot growth and development in pruned tea plants (Camellia sinensis (L.) O. Kuntz)

Author

Arkorful, Emmanuel, primary, Yu, Ying, additional, Chen, Changsong, additional, Lu, Li, additional, Hu, Shunkai, additional, Yu, Hanpu, additional, Ma, Qingping, additional, Thangaraj, Kuberan, additional, Periakaruppan, Rajiv, additional, Jeyaraj, Anburaj, additional, Chen, Xuan, additional, and Li, Xinghui, additional

Published
2020
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50. A novel insight into nitrogen and auxin signaling in lateral root formation in tea plant [Camellia sinensis (L.) O. Kuntze]

Author

Author), Shunkai Hu(Former Corresponding, primary, Zhang, Mi, additional, Yang, Yiqing, additional, Xuan, Wei, additional, Zou, Zhongwei, additional, Arkorful, Emmanuel, additional, Chen, Yi, additional, Ma, Qingping, additional, Jeyaraj, Anburaj, additional, Chen, Xuan, additional, and Author), Xinghui Li(New Corresponding, additional

Published
2020
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