China 
Africa 
Explore chapters and articles related to this topic
Introduction to the Kinetic Theory of Gases
Published in Caroline Desgranges, Jerome Delhommelle, A Mole of Chemistry, 2020
Caroline Desgranges, Jerome Delhommelle
Despite this, the news that there is an experiment suggesting the existence of vacuums starts to spread. Indeed, even if there are no scientific journals as we now have, this does not prevent scientists from exchanging ideas, for instance through letters they send to each other. One of the most important personages of the time is certainly Mersenne (1588–1648), a French theologian. From his austere monastic cell, he maintains a great epistolary correspondence with a multitude of intellectuals all over Europe, including Descartes, Fermat, van Helmont, Torricelli, Huygens, Pascal and Galileo to name a few. He has a keen scientific mind, with broad interests ranging from mathematics to acoustics. Indeed, he writes about the vibrations of strings in “Harmonicorum Libri” (1636) following his discussions with scientists and musicians of the time. It is a wonderful book that, nowadays, makes Mersenne one of the fathers of acoustics (the science behind sounds). He is also a brilliant mathematician who studies prime numbers (for instance 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31…). He observes a strange pattern. Consider the prime number 3; it can be written as 4 – 1 or also as 22 – 1. Now consider 7; it is equal to 8 – 1 or 23 – 1. The same is true with 31 which is also 32 – 1 or 25 – 1. As you can see a formula emerges: The form 2n – 1 gives a prime number if n is prime itself! Nowadays, we call them the Mersenne numbers Mn (n being a prime number). For example, the first Mersenne number is related to the first prime (2) and we have then M2 = 22 – 1 = 3. The same is true with the second Mersenne number (using the second prime: 3) M3 = 23 – 1 = 7, ditto with M5 = 25 – 1 = 31, M7 = 27 – 1 = 127. Note that, as of December 2018, 51 Mersenne numbers are known, the biggest being M82,589,933 which is also the largest known prime number! Like many of the other Mersenne numbers, it was discovered by a calculus distributed under the aegis of the Great Internet Mersenne Prime Search (GIMPS) project.
A framework on task configuration and execution for distributed geographical simulation
Published in International Journal of Digital Earth, 2021
Fengyuan Zhang, Min Chen, Ming Wang, Zihuan Wang, Shuo Zhang, Songshan Yue, Yongning Wen, Guonian Lü
Third, due to the complexity of geographical simulations, scheduling volunteers' computers and balancing the task load to enhance the running performance of geographical simulations are still challenges for scholars. For time-consuming models, users employ a collection of many computers to run models in order to save time and integrate many technologies, such as parallel running and clusters (Buyya 1999; Zaharia et al. 2010; Deng, Desjardins, and Delmelle 2019). With the development of computer technology, the number of projects for volunteered computers in other domains (biology, astronomy, chemistry, mathematics, etc.) is increasing and includes BOINC, World Community Grid, Great Internet Mersenne Prime Search (GIMPS), SETI@home, Folding@home, and Genome@Home (Anderson et al. 2002; Wanko and Venable 2002; Anderson 2004; Larson et al. 2009; Hachmann et al. 2011). These projects are forms of distributed computing that assemble volunteered computing and can support research without much funding in massive computation (Anderson 2004; Korpela 2012). This approach is suitable for simulation tasks with massive and similar computing tasks. However, geographical simulations, which involve various modes, are complex. Moreover, different graphical simulations have different model configurations. Therefore, flexible simulation configurations are necessary, and related research is lacking.