scholarly journals STUDENT'S PERCEPTION OF THE POTENTIAL UTILIZATION OF WIND AS A SOURCE OF ENERGY AROUND THE SOUTH COAST OF JAVA

EduFisika ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 56-63
Author(s):  
Naura Ahadiyah Rahmi ◽  
Sundarti Sundarti

Wind is a gas flow that is on a large scale and in large quantities caused by the rotation of the earth and the difference in the air around it. This study aims to analyze students' knowledge about the potential use of wind as an energy source along the southern coast of Java. This research method was qualitative with respondents from physics education students at the University of Jember batch 2020. The research data collection uses a questionnaire (Google Form). The wind potential around the southern coast of Java has an average speed of 3-8 m/s. In this area, it is very suitable to build a wind power plant because the average wind speed to drive the wind turbine in this power plant is between 5-8 m/s. Students have good knowledge about the potential use of wind as an energy source along the southern coast of Java.

2014 ◽  
Vol 986-987 ◽  
pp. 315-321
Author(s):  
Wen Bin Xiong ◽  
Hou Ming Zhang ◽  
Bo Ping Zhang ◽  
Hu Wei Li ◽  
Gang Wang ◽  
...  

In recent years, advanced small nuclear power reactors, namely small modular reactors (SMRs), gained widespread attention. In areas where energy can’t be provided by large scale reactors and the nuclear power plants with large scale reactors can’t compete with the non-nuclear power plant technology, SMRs, as a versatile distributed integrated energy source, which result in expanding peaceful applications of nuclear energy, have enormous potential. This article describes the characteristics and analyzes prospects and challenges of SMRs.


Tibuana ◽  
2020 ◽  
Vol 3 (01) ◽  
pp. 61-66
Author(s):  
Sagita Rochman

At present the use of wind energy in Indonesia is still relatively low, but has enormous potential. One reason is because the average wind speed in the territory of Indonesia is classified as low wind speed, which ranges from 3 m / s to 5 m / s making it difficult to produce electrical energy on a large scale. However, the wind potential in Indonesia is available almost all year long, making it possible to develop small-scale power generation systems. Innovations in modifying windmills need to be developed so that in conditions of low wind speeds can produce electrical energy. In this research, a prototype was developed by designing a vertical axis windmill power plant model Savonius using a permanent magnet generator, which can produce optimal electrical energy by utilizing relatively low wind speeds.From the generator test it was found that with a rotor rotation of 50 rpm up to 500 rpm can produce an electrical voltage of 0.02V to 10V and an electric current of 0.60A to 4.53A.


VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.


2020 ◽  
Vol 140 (6) ◽  
pp. 531-538
Author(s):  
Kotaro Nagaushi ◽  
Atsushi Umemura ◽  
Rion Takahashi ◽  
Junji Tamura ◽  
Atsushi Sakahara ◽  
...  

Author(s):  
Angela Dranishnikova

In the article, the author reflects the existing problems of the fight against corruption in the Russian Federation. He focuses on the opacity of the work of state bodies, leading to an increase in bribery and corruption. The topic we have chosen is socially exciting in our days, since its significance is growing on a large scale at all levels of the investigated aspect of our modern life. Democratic institutions are being jeopardized, the difference in the position of social strata of society in society’s access to material goods is growing, and the state of society is suffering from the moral point of view, citizens are losing confidence in the government, and in the top officials of the state.


2012 ◽  
Vol 608-609 ◽  
pp. 1120-1126 ◽  
Author(s):  
De Shun Wang ◽  
Bo Yang ◽  
Lian Tao Ji

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.


2021 ◽  
Vol 13 (6) ◽  
pp. 1180
Author(s):  
Da Guo ◽  
Xiaoning Song ◽  
Ronghai Hu ◽  
Xinming Zhu ◽  
Yazhen Jiang ◽  
...  

The Hindu Kush Himalayan (HKH) region is one of the most ecologically vulnerable regions in the world. Several studies have been conducted on the dynamic changes of grassland in the HKH region, but few have considered grassland net ecosystem productivity (NEP). In this study, we quantitatively analyzed the temporal and spatial changes of NEP magnitude and the influence of climate factors on the HKH region from 2001 to 2018. The NEP magnitude was obtained by calculating the difference between the net primary production (NPP) estimated by the Carnegie–Ames Stanford Approach (CASA) model and the heterotrophic respiration (Rh) estimated by the geostatistical model. The results showed that the grassland ecosystem in the HKH region exhibited weak net carbon uptake with NEP values of 42.03 gC∙m−2∙yr−1, and the total net carbon sequestration was 0.077 Pg C. The distribution of NEP gradually increased from west to east, and in the Qinghai–Tibet Plateau, it gradually increased from northwest to southeast. The grassland carbon sources and sinks differed at different altitudes. The grassland was a carbon sink at 3000–5000 m, while grasslands below 3000 m and above 5000 m were carbon sources. Grassland NEP exhibited the strongest correlation with precipitation, and it had a lagging effect on precipitation. The correlation between NEP and the precipitation of the previous year was stronger than that of the current year. NEP was negatively correlated with temperature but not with solar radiation. The study of the temporal and spatial dynamics of NEP in the HKH region can provide a theoretical basis to help herders balance grazing and forage.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2499
Author(s):  
Krzysztof Jastrzębski ◽  
Piotr Kula

The energetic and climate crises should pose a challenge for scientists in finding solutions in the field of renewable, green energy sources. Throughout more than two decades, the search for new opportunities in the energy industry made it possible to observe the potential use of hydrogen as an energy source. One of the greatest challenges faced by scientists for the sake of its use as an energy source is designing safe, usable, reliable, and effective forms of hydrogen storage. Moreover, the manner in which hydrogen is to be stored is closely dependent on the potential use of this source of green energy. In stationary use, the aim is to achieve high volumetric density of the container. However, from the point of view of mobile applications, an extremely important aspect is the storage of hydrogen, using lightweight tanks of relatively high density. That is why, a focus of scientists has been put on the use of carbon-based materials and graphene as a perspective solution in the field of H2 storage. This review focuses on the comparison of different methods for hydrogen storage, mainly based on the carbon-based materials and focuses on efficiently using graphene and its different forms to serve a purpose in the future H2-based economy.


Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 811
Author(s):  
Yaqin Hu ◽  
Yusheng Shi

The concentration of atmospheric carbon dioxide (CO2) has increased rapidly worldwide, aggravating the global greenhouse effect, and coal-fired power plants are one of the biggest contributors of greenhouse gas emissions in China. However, efficient methods that can quantify CO2 emissions from individual coal-fired power plants with high accuracy are needed. In this study, we estimated the CO2 emissions of large-scale coal-fired power plants using Orbiting Carbon Observatory-2 (OCO-2) satellite data based on remote sensing inversions and bottom-up methods. First, we mapped the distribution of coal-fired power plants, displaying the total installed capacity, and identified two appropriate targets, the Waigaoqiao and Qinbei power plants in Shanghai and Henan, respectively. Then, an improved Gaussian plume model method was applied for CO2 emission estimations, with input parameters including the geographic coordinates of point sources, wind vectors from the atmospheric reanalysis of the global climate, and OCO-2 observations. The application of the Gaussian model was improved by using wind data with higher temporal and spatial resolutions, employing the physically based unit conversion method, and interpolating OCO-2 observations into different resolutions. Consequently, CO2 emissions were estimated to be 23.06 ± 2.82 (95% CI) Mt/yr using the Gaussian model and 16.28 Mt/yr using the bottom-up method for the Waigaoqiao Power Plant, and 14.58 ± 3.37 (95% CI) and 14.08 Mt/yr for the Qinbei Power Plant, respectively. These estimates were compared with three standard databases for validation: the Carbon Monitoring for Action database, the China coal-fired Power Plant Emissions Database, and the Carbon Brief database. The comparison found that previous emission inventories spanning different time frames might have overestimated the CO2 emissions of one of two Chinese power plants on the two days that the measurements were made. Our study contributes to quantifying CO2 emissions from point sources and helps in advancing satellite-based monitoring techniques of emission sources in the future; this helps in reducing errors due to human intervention in bottom-up statistical methods.


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