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Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 90
Author(s):  
Shuhua Peng ◽  
Yu Wu ◽  
Jing Tao ◽  
Jianbin Chen

Airflow classification is the key technology for the dry separation of manufactured sand. To solve the problem of low separation accuracy and poor gradation grade, the classification process of manufactured sand under different inlet and outlet airflow velocities changes in the multi-air inlet classifier is simulated by using Barracuda based on Computational Particle Fluid Dynamics (CPFD) method. The influence of various airflow velocity in air inlets and outlet on the sand classification is analyzed. The optimal combination of airflow velocity that meets the design goals is obtained. The results show that the airflow velocity and location of the air inlet and outlet have a significant impact on medium-grained (0.15~1.18 mm) and fine-grained (0.075~0.3 mm) sand. Adjusting the airflow velocity at air inlet 2 and air outlet can most effectively change the overall sand separation effect, while 41 m/s (inlet 2) and 6 m/s (outlet) would be the best velocity combination.


2022 ◽  
Author(s):  
Daniel Hoyer

An avid reader of history will be quite familiar with the rich, emotive narratives detailing the tragic decline and ultimate fall of once mighty civilizations; Rome succumbing to barbarian hordes, Alexander of Macedon’s and Chinggis Khan’s spear-won empires splitting into warring factions, and the demise of the great Inca or Maya civilizations are just a few such examples. On the other side of the stacks, similarly grandiose narratives document some group’s incredible growth and spread taking over vast territories and populations. These tell typically of societies coming to dominate a region, often in the face of overwhelming odds and tribulation or through some precocious development of a key technology or strategy that later becomes widespread. Here, I take stock of previous approaches to studying function – from growth and development to crisis and collapse to resilience – and ask what is the most fruitful lens with which to view fluctuations in how societies function and change over time, as this review essay attempts to accomplish.


Author(s):  
Dewar Rico-Bautista ◽  
César D. Guerrero ◽  
César A. Collazos ◽  
Gina Maestre-Gongora ◽  
María Camila Sánchez-Velásquez ◽  
...  

Author(s):  
Nicole Dimos ◽  
Carl P. O. Helmer ◽  
Andrea M. Chánique ◽  
Markus C. Wahl ◽  
Robert Kourist ◽  
...  

Enzyme catalysis has emerged as a key technology for developing efficient, sustainable processes in the chemical, biotechnological and pharmaceutical industries. Plants provide large and diverse pools of biosynthetic enzymes that facilitate complex reactions, such as the formation of intricate terpene carbon skeletons, with exquisite specificity. High-resolution structural analysis of these enzymes is crucial in order to understand their mechanisms and modulate their properties by targeted engineering. Although cryo-electron microscopy (cryoEM) has revolutionized structural biology, its applicability to high-resolution structural analysis of comparatively small enzymes has so far been largely unexplored. Here, it is shown that cryoEM can reveal the structures of plant borneol dehydrogenases of ∼120 kDa at or below 2 Å resolution, paving the way for the rapid development of new biocatalysts that can provide access to bioactive terpenes and terpenoids.


2022 ◽  
Vol 2146 (1) ◽  
pp. 012030
Author(s):  
Juan Guo

Abstract With the rapid development of computer technology, the importance of database systems as an indispensable part of information systems is becoming more and more prominent. And nowadays, the society has been increasingly using modern means to program databases. Database is a large and complex, huge amount of data and has a certain structure and independence of the important system, its programming requires certain technical means, the author will be in the text for the database programming involved in the key technology to explain.


2022 ◽  
Author(s):  
Ashish Gaur ◽  
Vikas Pundir ◽  
Krishankant . ◽  
Ritu Rai ◽  
Baljeet Kaur ◽  
...  

Electrocatalytic water splitting is one of the key technology for the future energy systems envisioned for the storage of energy obtained from variable renewables and green fuels. The development of...


2021 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Yihang Chen ◽  
Zening Cao ◽  
Jinxin Wang ◽  
Yan Shi ◽  
Zilong Qin

In the process of global information construction, different fields have built their own discrete global grid systems (DGGS). With the development of big data technology, data exchange, integration, and update have gradually become a trend, as well as the associative integration of different DGGS. Due to the heterogeneity of DGGS and the different encoding rules, how to build the encoding conversion rules and data mapping relationship between the same object in various DGGS is an effective support and key technology to achieve the interoperability of DGGS. As a kind of multipurpose DGGS, the quaternary triangular mesh (QTM) has become an effective spatial framework for constructing the digital earth because of its simple structure. At present, there are many schemes for QTM encoding research, which plays a key role in the development of QTM, but at the same time, it also leads to difficulties in the communication and integration of QTM under different encoding. In order to solve this problem, we explore the characteristics of QTM encoding, and put forward three conversion algorithms: resampling conversion algorithm, hierarchical conversion algorithm, and row–column conversion algorithm.


2021 ◽  
Author(s):  
Luyang Duanmu ◽  
Yuanhua yu ◽  
Hongzhuang Guo

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 62
Author(s):  
Xianshan Dong ◽  
Xinlong Huang ◽  
Guizhen Du ◽  
Qinwen Huang ◽  
Yixiong Huang ◽  
...  

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To solve installation errors and obtain the input acceleration in the calibration of the accelerometer, a calibration method based on the rotation principle using a double turntable centrifuge is proposed in this work. The key operation is that the sub-turntable is rotated to make the input axis of the accelerometer perpendicular to the direction of the centripetal acceleration vector. Models of installation errors of angle and radius were built. Based on these models, the static radius and input acceleration can be obtained accurately, and the calibration of the scale factor, nonlinearity and asymmetry can be implemented. Using this method, measurements of the MEMS accelerometer with a range of ±30 g were carried out. The results show that the discrepancy of performance obtained from different installation positions was smaller than 100 ppm after calibrating the input acceleration. Moreover, the results using this method were consistent with those using the back-calculation method. These results demonstrate that the effectiveness of our proposed method was confirmed. This method can measure the static radius directly eliminating the installation errors of angle and radius, and it simplifies the accelerometer calibration procedure.


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