Tuning of Calcite Crystallographic Orientation to Support Brachiopod Lophophore

Organisms exert exquisite control on mineral formation by tuning structural and material properties to meet functional requirements. Brachiopods are sessile marine organisms that filter feed via a large lophophore which is supported by a delicate calcite loop that grows from the inner surface of the shell. How does the loop support the weight of the large lophophore? Electron backscatter diffraction (EBSD) and nanoindentation analyses of the loop as it emerges from the shell of Laqueus rubellus reveal that calcite fiber crystallography generates asymmetry in the material properties of the structure. In the core of the emergent loop, the fibers are short and kernel‐like. Either side of the core, the long fibers have a different crystallographic orientation and resultant material properties. fibers on the anterior, load‐bearing side, are harder (H = 3.76 ± 0.24 GPa) and less stiff (E = 76.87 ± 4.87 GPa) than the posterior (H = 3.48 ± 0.31 GPa, E = 81.79 ± 5.33 GPa). As a consequence of the asymmetry in the material properties, the loop anterior may be more flexible under load. The brachiopod strategy of tuning crystallographic orientation to confer spatially determined material properties is attractive for additive manufacturing of synthetic materials that have complex heterogeneous material property requirements

A High-Temperature-Resistant Inorganic Matrix for Concrete Structures Enhanced by Fiber-Reinforced Polymer

This paper probed deep into a high-temperature resistant inorganic matrix: alkali-activated slag cement (AASC), which is a kind of cementitious material prepared by alkali-activator and pozzolanic or latent hydraulic material. Firstly, the mix ratio of the AASC was optimized to improve the wettability and mechanical properties. Then, the effects of the adhesive matrix and the type of fiber-reinforced polymer (FRP) were observed through FRP-to-concrete bond tests on 93 specimens. The test results, coupled with anchorage analysis, indicate that the AASC has comparable reinforcing effects as those of organic epoxy matrix; the anchorage length of FRP sheets has a significant influence on the failure behavior and failure mode of FRP-enhanced concrete structures. In addition, our tests prove that the AASC has favorable high-temperature resistance and bonding effects. The research results provide a good reference for the design and application of inorganic matrix for FRP-enhancement of concrete structures

A Comparative Study on Sino-UK Postgraduate Professional Degree Education and Implications

Chinese postgraduate professional degree education has undergone 26 years of development, and has achieved a great progress. But compared with the developed nations in the world, China is still in its infantry stage, and needs to learn from the western developed countries’ experiences in this field. This paper makes a comparative analysis of the differences between China and UK in postgraduate professional degree education. It finds that there are significant differences between the two countries in the aspects of programme setting, schooling duration, admissions, curriculum design, teaching delivery, quality control system, etc. The findings imply that China should try to give more authority to universities in programme setting and admissions, and Chinese universities should innovate ways of teaching delivery and systems of quality control

Controlling a Quadrotor Carrying a Cable-Suspended Load to Pass Through a Window

In this paper, we design an optimal control system for a quadrotor to carry a cable-suspended load flying through a window. As the window is narrower than the length of the cable, it is very challenging to design a practical control system to pass through it. Our solution includes a system identification component, a trajectory generation component, and a trajectory tracking control component. The exact dynamic model that usually derived from the first principles is assumed to be unavailable. Instead, a model identification approach is adopted, which relies on a simple but effective low order equivalent system (LOES) to describe the core dynamical characteristics of the system. After being excited by some specifically designed manoeuvres, the unknown parameters in the LOES are obtained by using a frequency based least square estimation algorithm. Based on the estimated LOES, a numerical optimization algorithm is then utilized for aggressive trajectory generation when relevant constraints are given. The generated trajectory can lead to the quadrotor and load system passing through a narrow window with a cascade PD trajectory tracking controller. Finally, a practical flight test based on an Astec Hummingbird quadrotor is demonstrated and the result validates the proposed approach

Integration of the Confucian Culture on Cross-Cultural Conflict Management: The Role of the COVID-19 Pandemic

Cross-culture conflict management is the major challenge for the Chinese enterprises going global along the Belt and Road Initiative. This study explores the feasibility of integrating the Confucian culture into cross-culture conflict management, and a special role is given to the COVID-19 pandemic. We combine the Confucian culture values and Hofstede’s cultural dimension theory and adopt the questionnaire survey methods on the Chinese multinational enterprises’ employees. The Cronbach’s Alpha method is also deployed to test the reliability and validity of the data. We find the significant integration of the Confucian culture into cross-culture conflict management. Furthermore, 16 sub-values of the Confucian culture are suggested to mitigate the cross-culture conflicts in multinational enterprises effectively. The findings imply that Chinese enterprises should consider new strategies to manage the cross-culture conflicts, especially during the COVID-19 pandemic

Sustainable economic growth via human capital and cleaner energy: evidence from non-parametric panel methods

The association between resource rents and economic growth is one of the key issues that have attracted the attention of both policymakers and scholars. Several attempts have been made regarding the association, yet the literature holds the gap. The present research intends to explore the connection between natural resource volatility and economic performance in seven (G-7) countries. For the time frame from1990 to 2020, this study also examines the role of technological innovation (TI), human capital (HCI), and research and development budget for renewable energy (RER&D). Empirical results asserted that the variables under study are cointegrated. Employing a novel non-parametric panel quantile method of moments regression and quantile-on-quantile, the outcomes propose that natural resources volatility significantly affects EP throughout the quantiles. This negative impact is valid for the aggregate panel of countries and cross-sections. Natural resource volatility supports the resource curse hypothesis for G7 economies. On the other hand, HCI and TI are significant economic performance factors. From lower to higher quantiles, the magnitude and significance levels increase. The variable for cleaner energy investment is also positively related to economic performance yet insignificant in the higher quantile. The study recommends channeling natural resource rents to effectively and fully transfer the full potential of natural resources to other real sectors of the economy to fully utilize the benefit from it

Expression of cocaine- and amphetamine-regulated transcript (CART) in hen ovary

Cocaine- and amphetamine-regulated transcript (CART), discovered initially by via differential display RT-PCR analysis of brains of rats administered cocaine, is expressed mainly in central nervous system or neuronal origin cells, and is involved in a wide range of behaviors, such as regulation of food intake, energy homeostasis, and reproduction. The hens egg-laying rate mainly depends on the developmental status of follicles, expression of CART have not been identified from hen follicles, the regulatory mechanisms of CART biological activities are still unknown. The objective of this study was to characterize the mRNA expression of CART in hen follicular granulosa cells and determine CART peptide localization and regulatory role during follicular development