Simulating NACA Equations Used in Optimizing Wind Turbine Blade Design: محاكاة معادلات NACA واستخدامها لتحسين تصميم شفرة العنفة الريحية

Aerodynamic scientists are interested in geometry definition and possible geometric shapes that would be useful in design. This paper illustrates a simulation of a NACA four digits airfoil blade profile using MATLAB. As airfoil design became more sophisticated, this basic approach has been modified to include additional variables, and suggestions for the chord line length at the root and at the end of the blade. as well as changes in the twisting angle of the blade and its thickness, this helps to reduce the weight of the blade significantly Simulating NACA equations is very useful in obtaining coordinates of airfoil curvature for the whole series of NACA four digits, which is very effective in optimizing blade design. In order to get an optimal operating performance and high efficiency for the airfoil, the blade surface must be smooth and does not suffer any discontinuities or undefined cases, which cause separation of the boundary layer during the airflow, and get as a result great energy losses. Therefore, the conditions for the continuity of the blade was extracted using mathematical analysis, so the air flow does not suffer any interruptions which reduce the efficiency. This enable us to determine the locations of the maximum thickness of the blade sections on the chord along the blade, in addition to specifying conditions for the chord line length at the root and at the end of the blade which keep the blade curvature continuous and doesn’t have any irregular points, which also facilities writing the necessary programs.

Heterothermy in a Small Passerine: Eastern Yellow Robins Use Nocturnal Torpor in Winter

Torpor is a controlled reduction of metabolism and body temperature, and its appropriate use allows small birds to adapt to and survive challenging conditions. However, despite its great energy conservation potential, torpor use by passerine birds is understudied although they are small and comprise over half of extant bird species. Here, we first determined whether a free-living, small ∼20 g Australian passerine, the eastern yellow robin (Eopsaltria australis), expresses torpor by measuring skin temperature (Ts) as a proxy for body temperature. Second, we tested if skin temperature fluctuated in relation to ambient temperature (Ta). We found that the Ts of eastern yellow robins fluctuated during winter by 9.1 ± 3.9°C on average (average minimum Ts 30.1 ± 2.3°C), providing the first evidence of torpor expression in this species. Daily minimum Ts decreased with Ta, reducing the estimated metabolic rate by as much as 32%. We hope that our results will encourage further studies to expand our knowledge on the use of torpor in wild passerines. The implications of such studies are important because species with highly flexible energy requirements may have an advantage over strict homeotherms during the current increasing frequency of extreme and unpredictable weather events, driven by changing climate.

PAUD Teacher Strategies in Supporting Learning in The Covid-19 Pandemic Period

The existence of COVID-19 which still hit Indonesia until in November 2020 had a negative impact on education in Indonesia, especially early childhood education. This makes learning, which was a face-to-face system, must be changed to distance education. In order for learning to continue optimally, of course, the teacher must be able to apply different learning strategies. In the pandemic era, schools implement online learning strategies, including at the Playgroup level. Online learning for children, of course, presents its challenges for the teachers. This study aims to investigate online learning strategies at the playgroup level. Play is also a means for children to channel their great energy and discover new things that were previously unknown in a fun way. And this is certainly different from learning that is understood by adults with all the rules and demands at the end. Playing (while learning) in early childhood has a purpose that adults may not realize, where when a child plays, in fact he is developing the potential that exists within him to become a solid initial capital for himself in the future when facing problems in life. This paper is expected to provide references and education to parents and early childhood teachers in particular to be able to understand the world of early childhood, one of which is by understanding the nature of play and the meaning of play for early childhood. This is obtained by exploring various sources from several literatures from the results of research and thought where the results can be used for early childhood parents and teachers to be more precise in assisting and designing learning for early childhood so that the pearl of early childhood learning, namely playing while learning can be achieved.

Computer-Aided Evaluation of Ethanol Production from a Continuous Operating Mode using Simulink

Fossil fuels have become a great energy source worldwide. However, its prolonged use has caused severe environmental pollution problems. Biofuels generated from biomass as a product of microbial biotechnology emerge as an alternative to the use of compounds derived from oil. Therefore, their production results in complex experiments and source investment. That is why engineering studies implementation using mathematical models and simulation techniques should be specified in bioprocesses. The latter focused on optimizing the process parameters, maximizing productivity, generating greater profitability, and reducing cost. This research aimed at the computer-assisted evaluation of obtaining bioethanol from Saccharomyces cerevisiae to determine the most critical factors in the production process using a continuous mode. It was determined that the feed rate significantly influences the bioethanol volumetric productivity.

Design and Analysis of Lightweight Lower Limb Exoskeleton for Military Usage

Nowadays, due to technological advancement, weapons are becoming smaller in size, which leads to the number of weapons carried by a single person increasing. As the number of weapons is increasing, then the capacity of the load carriage system of military personnel causes a great energy loss to carry weight. Also, carrying a weight of about 25 kg to 50 kg in different terrain causes different foot injuries which create a strain on the human body. An exoskeleton is a device used to replicate the motion of the human body so that humans can be used to control mechanical power for working on different operations which are beyond human strength. The exoskeleton technology makes it possible to reduce the energy loss of military personnel to produce controlled motion of the exoskeleton in different terrain. Hence, this project is aims to design a lower limb exoskeleton for carrying military load carriage systems. The designing and simulating the lower limb exoskeleton is done on fusion 360. Keywords: lower limb exoskeleton, military exoskeleton, exoskeleton design, exoskeleton analysis

Walter Jakob Gehring. 20 March 1939—29 May 2014

Walter Jakob Gehring was one of the most influential developmental biologists of the last 50 years. First as a student with Professor Ernst Hadorn in Zurich, later as a postdoc in Yale and finally as group leader in Basel, he was involved in a number of major discoveries that had a profound impact in the understanding of the genetic and molecular mechanisms of animal development, not only for the fruit fly Drosophila but for the whole animal kingdom. Throughout his career Gehring demonstrated an outstanding ability to recognize key problems and then to push experimental work on these problems with great energy. Gehring pioneered the application of molecular techniques to developmental problems, an approach that was at the root of many of his contributions. His laboratory was involved in a number of key findings: the first cloning of a Hox gene, the discovery of the homeobox, the enhancer trap method, and the remarkable conservation of features of the visual system in metazoans. He was an excellent speaker, with special ability to emphasize the relevant aspects of his work and to draw conclusions of general interest. This attracted a number of gifted students and postdocs who were key for the success of his research group. Passionately interested in science, he was also very excited about other scientific disciplines; he was an accomplished bird watcher and was also fascinated by marine life. But he also had non-scientific interests, too; he claimed to be an excellent football player and frequently commented that he had had to decide whether to be a scientist or a professional footballer. He decided on the former, but one wonders if he might have been a Swiss version of Messi or Ronaldo.

A Mathematical Description of Selected Energy Transition Scenarios in the 21st Century, Intended to Realize the Main Goals of the Paris Climate Agreement

On 4 November 2016, the historic Paris Climate Agreement of the United Nations entered into force, requiring signatory countries to maintain global warming at the level of 1.5–2 °C. According to the calculations of the Intergovernmental Panel on Climate Change (IPCC), to achieve this goal, a 2/3 reduction in greenhouse gas energy emissions into the atmosphere compared with gaseous energy-related emissions in 2019 (33.3 Gt) by about 2050 (1.5 °C) or by 2070 (2 °C) is required. According to the International Renewable Energy Agency (IRENA), this is only possible with the implementation of a great energy transition from the use of currently dominant fossil hydrocarbon fuels—coal, oil, and natural gas—to the predominant use of renewable energy sources (RES) by 2040–2050, when the share of renewable energy in the total energy balance will reach 40% and above. In this work, mathematical description of an upcoming energy transition has been carried out, including long-term scenario writing of the world’s demographic dynamics and global energy demand, calculation of the dynamics of industrial CO2 emissions and CO2 accumulation in the Earth’s atmosphere, as well as the corresponding changes in the average global temperature of the Earth’s surface in the 21st century. A mathematical description of the impact of energy consumption on climate change was carried out taking into account long-term trends in the dynamics of energy consumption. Using the performed mathematically-oriented scenario writing, it is suggested that a great energy transition with the achievement of the goals of the Paris Agreement is possible only by 2060. Renewable energy could sufficiently displace and replace hydrocarbon fuels to achieve climate safety without compromising economic development. As a result, humanity will receive an environmentally friendly decentralized distributed energy system, connected by «smart» grids, controlled by intelligent digital technologies.

Key Strata Inducing Dynamic Disasters Based on Energy Condition: Criterion and Application

The thick and hard rock strata (THRS) exist widely in coal measure strata, which control the movements of overlying rock strata in stopes. When THRS break, great energy is released, which could aggravate the risks of coal and gas outburst, rock burst, and other dynamic disasters. Therefore, the foundation and key of preventing dynamic disasters are to distinguish the THRS that could induce coal-rock dynamic disasters and to analyze the laws of rock stratum breaking and energy releasing. The paper proposed the theoretical calculation methods of the energy accumulation and attenuation of rock breaking which is greatly affected by the hanging length of rock strata and the spreading distance. One or more roof strata that play a leading role in inducing dynamic disasters of the underlying coal mass are defined as the key disaster-inducing strata (KDIS). The disaster-inducing coefficient (DIC) is defined and used as the criterion of KDIS. The greater the source energy, the shorter the spreading distance, and the smaller the attenuation coefficient are, the easier the roof strata are to become KDIS. The disaster-inducing ability of the main THRS was analyzed, and the igneous sill was judged as KDIS, taking the Yangliu Coal Mine as project background. The breaking laws of the igneous sill were obtained by the methods of UDEC numerical simulation and microseismic monitoring, which verified the criterion of KDIS.