Numerical Simulation and Experimental Validation of Surface Roughness by the Smoothing Small Ball-Burnishing Process

The smoothing ball-burnishing process has commonly been used as a post-processing method to reduce the irregularities of machined surfaces. However, the mechanism of this process has rarely been examined. In this study, a simulation procedure is proposed to predict the surface roughness of a burnished workpiece under varying burnishing forces. The roughness of the workpiece surface was firstly approximated by parabolic functions. The burnishing process was then numerically simulated through two steps, namely the elastic–plastic indentation of the burnishing ball on the workpiece’s surface, and the sliding movement of the burnishing tool. The results of the simulation were verified by conducting small ball-burnishing experiments on oxygen-free copper (OFC) and Polmax materials using a load cell-embedded small ball-burnishing tool. For the OFC material, the optimal burnishing force was 3 N. The obtained experimental surface roughness was 0.18 μm, and the simulated roughness value was 0.14 μm. For the Polmax material, when the burnishing force was set at its optimal value—12 N, the best experimental and simulated surface roughness were 0.12 μm and 0.10 μm, respectively

Whole plant 13CO2-labelling for carotenoid turnover analysis in leaves

Understanding the regulation of carotenoid metabolism (synthesis, conversion and degradation) in plants requires turnover measurement of individual carotenoids, apocarotenoids and precursors. In our previous study, we demonstrated continuous turnover of carotenes together with chlorophyll a in illuminated leaves of Arabidopsis thaliana by using 14CO2 pulse-chase labeling. In contrast to carotenes and chlorophyll a that are bound in photosystem reaction center complexes, xanthophylls and chlorophyll b, which are bound in light-harvesting antenna complexes, were hardly labeled by 14C within a day, even when the total amount of xanthophyll-cycle pigments (zeaxanthin, antheraxanthin, and violaxanthin) was increasing, presumably by de novo synthesis, under strong light. In order to obtain quantitative information of carotenoid turnover in leaves of intact plants, we constructed a labelling chamber in which 15 small plants, such as Arabidopsis, can be synchronously labelled by 13CO2 over days. First we tested the chamber by operating with 12CO2 while continuously monitoring the conditions inside the chamber (light intensity, air temperature and humidity, CO2 concentration, pressure). Then a protocol was established to grow 15 Arabidopsis plants (wildtype Columbia-0) in the chamber under the light intensity of ~200 µmol photons m-2 s-1. Switching to 13CO2, plants were grown in the chamber under the same conditions for up to seven days. LC-MS analysis of pigments extracted from rosette leaves of the 13C-labelled Arabidopsis plants showed a substantial incorporation of photosynthetically fixed 13C into β-carotene and lutein along with chlorophyll a and chlorophyll b. The proposed system can be used for pulse-chase experiments (from 12CO2 to 13CO2 and vice versa) to estimate the turnover rate of carotenoids and chlorophylls as well as other plant metabolites. Results from such experiments could provide missing pieces of information in the current picture of metabolic pathway regulation in plants

Combination of long-term 13CO2 labeling and isotopolog profiling allows turnover analysis of photosynthetic pigments in Arabidopsis leaves

BACKGROUND: Living cells maintain and adjust structural and functional integrity by continual synthesis and degradation of metabolites and macromolecules. The maintenance and adjustment of thylakoid membrane involve turnover of photosynthetic pigments along with subunits of protein complexes. Quantifying their turnover is essential to understand the mechanisms of homeostasis and long-term acclimation of photosynthetic apparatus. Here we report methods combining whole-plant long-term (13)CO(2) labeling and liquid chromatography - mass spectrometry (LC–MS) analysis to determine the size of non-labeled population (NLP) of carotenoids and chlorophylls (Chl) in leaf pigment extracts of partially (13)C-labeled plants. RESULTS: The labeling chamber enabled parallel (13)CO(2) labeling of up to 15 plants of Arabidopsis thaliana with real-time environmental monitoring ([CO(2)], light intensity, temperature, relative air humidity and pressure) and recording. No significant difference in growth or photosynthetic pigment composition was found in leaves after 7-d exposure to normal CO(2) (~ 400 ppm) or (13)CO(2) in the labeling chamber, or in ambient air outside the labeling chamber (control). Following chromatographic separation of the pigments and mass peak assignment by high-resolution Fourier-transform ion cyclotron resonance MS, mass spectra of photosynthetic pigments were analyzed by triple quadrupole MS to calculate NLP. The size of NLP remaining after the 7-d (13)CO(2) labeling was ~ 10.3% and ~ 11.5% for all-trans- and 9-cis-β-carotene, ~ 21.9% for lutein, ~ 18.8% for Chl a and 33.6% for Chl b, highlighting non-uniform turnover of these pigments in thylakoids. Comparable results were obtained in all replicate plants of the (13)CO(2) labeling experiment except for three that were showing anthocyanin accumulation and growth impairment due to insufficient water supply (leading to stomatal closure and less (13)C incorporation). CONCLUSIONS: Our methods allow (13)CO(2) labeling and estimation of NLP for photosynthetic pigments with high reproducibility despite potential variations in [(13)CO(2)] between the experiments. The results indicate distinct turnover rates of carotenoids and Chls in thylakoid membrane, which can be investigated in the future by time course experiments. Since (13)C enrichment can be measured in a range of compounds, long-term (13)CO(2) labeling chamber, in combination with appropriate MS methods, facilitates turnover analysis of various metabolites and macromolecules in plants on a time scale of hours to days. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13007-022-00946-3

Factors affecting collaboration in agricultural supply chain: A case study in the North Central region of Vietnam

AbstractBased on three fundamental theories, commitment-trust theory of relationship marketing, transaction cost theory, and force field theory, this study has examined the factors affecting collaboration in the agricultural supply chain in the North Central region of Vietnam by analyzing EFA, CFA, and SEM. The research results have shown that trust and commitment are two important antecedents of collaboration, and they have a positive effect on collaboration in the agricultural supply chain. Risk has a negative effect on collaboration and is explained based on the concept of understanding the nature of risk and the characteristics of the research context. The dark side of collaboration is opportunistic behavior, testing the influence of this factor and concluding that it is necessary to limit opportunistic behavior to enhance collaboration in the agricultural supply chain. It is shown that there is a difference in the level of collaboration among specific agricultural sectors in the North Central region, in which collaboration in cultivation and livestock sectors has a low level, but in aquaculture, it is higher. Similarly, contractual relationships are essential for promoting collaboration in the agricultural supply chain. From these research results, the study has proposed some practical solutions to increase collaborations in the agricultural supply chain in the North Central region of Vietnam