scholarly journals Evaluation of Transient Response of Different Earthing Configurations due to Lightning Impulses

2019 ◽  
Vol 8 (4) ◽  
pp. 6342-6346 ◽  
Keyword(s):  
Transient Response ◽  
System Performance ◽  
Electrical Equipment ◽  
Main Function ◽  
Soil Resistivity ◽  
Electrical Currents ◽  
The Past ◽  
The Earth ◽  
Simulation Results ◽  
Soil Ionization

Earthing system is very important in order to protect the electrical equipment as well as the human’s safety against over voltages. The main function of the earthling system is to remove unwanted excessive electrical currents caused by unusual conditions such as fault and lightning or switching over voltages by providing a low resistance path to the earth. Researchers had studied the behaviour of the earthling system to improve its performance for the past few years. There are few factors that influence the performance of the earthling system such as soil resistivity and soil ionization which need to be focused in order to improve the earthling. Thus, this paper evaluates on the factors that affect the behaviour of the earthling system based on simulation works using MATLAB and Safe Grid Software. Some analytical calculations are used to obtain the soil resistivity and resistance as well as the touch and step voltages. The simulation results were validated based on comparison with other studies on the factors that influence the earthling system performance. The results reveal that the variation of soil resistivity, the configuration of electrodes, current magnitude and frequency dependence can result in a change of transient response of the systems.

scholarly journals The use of enhancement material in grounding system: a review

2019 ◽  
Vol 13 (2) ◽  
pp. 453 ◽  
Author(s):  
Aizat Azmi ◽  
Noor Azlinda Ahmad ◽  
Lau Kwan Yiew ◽  
Z. Abdul-Malek
Keyword(s):  
Moisture Content ◽  
High Voltage ◽  
System Performance ◽  
Soil Resistivity ◽  
Grounding System ◽  
Advantages And Disadvantages ◽  
The Past ◽  
System A ◽  
Surrounding Environment ◽  
Set Up

<p>This paper reviews the improvement of grounding impedance in grounding system by means of enhancement materials. Various enhancement materials for the past 20 years will be reviewed according to their advantages and disadvantages, followed by a focus on the technique for proper measurement set up based on the standard. In addition to that, the condition of enhancement materials under high voltage exposure is reviewed. Many researchers claim that soil resistivity, moisture content, and surrounding environment are the most contributed to the grounding system specifically on the grounding impedance. Hence, the utilization of enhancement materials is essential in order to maintain the grounding system performance.</p>

Priority Heuristic in MDRTDBS

2019 ◽  
Vol 09 ◽  
Author(s):  
Prakash Kumar Singh ◽  
Udai Shanker
Keyword(s):  
System Performance ◽  
Concurrency Control ◽  
Data Item ◽  
Main Function ◽  
Quality Estimation ◽  
C Language ◽  
Heuristic Approaches ◽  
High Workload ◽  
Simulation Results ◽  
Real Time Database

Background: Mobile distributed real time database is an emerging field of research. Transaction execute in these system should commit before elapsing the deadline. Assigning priority to arrived and executing transaction is the main function of transaction scheduler. Perform correct order of execution enhance the system performance in time constraint environment. In recent years a number of heuristic policies in DRTDBS are developed to enhance the quality estimation of scheduler. However due to various wireless limitations a very little work is investigated in the MDRTDBS. In this paper we have develop two heuristic policies and perform simulation using pessimistic and optimistic concurrency control algorithm to enhance the system performance. Objective: Two heuristic policies based on write only locks and number of same data item existence has been introduced. These heuristic approaches enhance the performance of MDRTDBS scheduler. Method: Develop two heuristic policies based on data contention which cope with CC policies like DHP-2PL and FBOCC. These policies count the number of write only locks and existence of number of same data item. Ultimately these policies enhance the system performance. Results:: Investigated the performance using simulator which is designed using C language. Based on these simulation results using pessimistic and optimistic CCs different graphs are plotted which shows the performance of system for these developed heuristic approaches. During simulation the low and high workload of transaction arrival is taken to fair investigate of these heuristic approaches. Conclusion: Simulation results show that the system performance is improved using these heuristic approaches. However, NWL_Modified heuristic approach outperform in MDRTDBS than earlier heuristic approaches.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

scholarly journals Calibration of Radiocarbon Dates for the Late Pleistocene Using U/Th Dates on Stalagmites

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld
Keyword(s):  
South Africa ◽  
Magnetic Dipole ◽  
Satisfactory Agreement ◽  
Late Pleistocene ◽  
Calibration Curve ◽  
Dipole Field ◽  
Radiocarbon Dates ◽  
The Past ◽  
The Earth ◽  
Magnetic Dipole Field

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.

Plant leaf recognition with shallow and deep learning: A comprehensive study

2020 ◽  
Vol 24 (6) ◽  
pp. 1311-1328
Author(s):  
Jozsef Suto
Keyword(s):  
Machine Learning ◽  
Plant Species ◽  
Research Area ◽  
Research Papers ◽  
Plant Leaf ◽  
Leaf Characteristics ◽  
The Past ◽  
The Earth ◽  
Test Sets ◽  
Comprehensive Study

Nowadays there are hundreds of thousands known plant species on the Earth and many are still unknown yet. The process of plant classification can be performed using different ways but the most popular approach is based on plant leaf characteristics. Most types of plants have unique leaf characteristics such as shape, color, and texture. Since machine learning and vision considerably developed in the past decade, automatic plant species (or leaf) recognition has become possible. Recently, the automated leaf classification is a standalone research area inside machine learning and several shallow and deep methods were proposed to recognize leaf types. From 2007 to present days several research papers have been published in this topic. In older studies the classifier was a shallow method while in current works many researchers applied deep networks for classification. During the overview of plant leaf classification literature, we found an interesting deficiency (lack of hyper-parameter search) and a key difference between studies (different test sets). This work gives an overall review about the efficiency of shallow and deep methods under different test conditions. It can be a basis to further research.

scholarly journals Trajectories of the Earth System in the Anthropocene

2018 ◽  
Vol 115 (33) ◽  
pp. 8252-8259 ◽  
Author(s):  
Will Steffen ◽  
Johan Rockström ◽  
Katherine Richardson ◽  
Timothy M. Lenton ◽  
Carl Folke ◽  
...  
Keyword(s):  
Global Economy ◽  
Human Action ◽  
Behavioral Changes ◽  
Earth System ◽  
New Governance ◽  
Sea Levels ◽  
Average Temperature ◽  
The Past ◽  
The Earth ◽  
Potential Threshold

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.

Whither democracy? Religion, politics and Islam

2011 ◽  
Vol 37 (4) ◽  
pp. 437-448 ◽  
Author(s):  
Fred Dallmayr
Keyword(s):  
Political Institutions ◽  
Religious Faith ◽  
Christian Right ◽  
Political Islam ◽  
The Past ◽  
The Earth ◽  
The World ◽  
Democratic Character

The question raised by the article is: can democracy be religious and, if so, how? Can religious faith be reconciled with modern democratic political institutions? The article takes its departure from the biblical admonition to believers to be ‘the salt of the earth’ — a phrase that militates against both world dominion and world denial. In its long history, Islam (like Christianity) has been sorely tempted by the lure of worldly power and domination. Nor is this temptation entirely a matter of the past (witness the rise of the Christian right and of ‘political Islam’ in our time). Focusing on contemporary Iran, the article makes a constitutional proposal which would strengthen the democratic character of the Iranian Republic without canceling religious faith. If adopted, the proposal would reinvigorate the ‘salt’ of Muslim faith thus enabling believers to live up to the Qur‘anic summons for freedom, justice and service in the world.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

2015 ◽  
Author(s):  
Meng-Shiun Tsai ◽  
Ying-Che Huang
Keyword(s):  
The Other ◽  
Contour Error ◽  
Interpolation Algorithm ◽  
Interpolation Scheme ◽  
Error Equation ◽  
The Past ◽  
Cnc Interpolation ◽  
Dynamic Errors ◽  
Simulation Results ◽  
The Given

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

Obituary notices of fellows deceased

1877 ◽  
Vol 25 (171-178) ◽  
Keyword(s):  
Past History ◽  
The Past ◽  
The Earth ◽  
History Of ◽  
Reign Of Terror ◽  
Accurate Observation

George Poulett Scrope. It is scarcely possible at the present day to realize the conditions of that intellectual “reign of terror” which prevailed at the commencement of the present century, as the consequence of the unreasoning prejudice and wild alarm excited by the early progress of geological inquiry. At that period, every attempt to explain the past history of the earth by a reference to the causes still in operation upon it was met, not by argument, but by charges of atheism against its propounder; and thus Hutton’s masterly fragment of a ‘Theory of the Earth,’ Playfair’s persuasive‘ Illustrations,’ and Hall’s records of accurate observation and ingenious experiment had come to be inscribed m a social Index Expurgatorius ,and for a while, indeed, might have seemed to be consigned to total oblivion. Equally injurious suspicions were aroused against the geologist who dared to make allusion to the important part which igneous forces have undoubtedly played in the formation of certain rocks; for the authority of Werner had acquired an almost sacred cha­racter; and “ Vulcanists ” and “ Huttonians ” were equally objects of aversion and contempt. To two men who have very recently—and within a few months of one another—passed away from our midst, science is indebted for boldly en­countering and successfully overcoming this storm of prejudice. Hutton and his friends lived a generation too soon ; and thus it was reserved tor Lyell and Scrope to carry out the task which the great Scotch philosopher had failed to accomplish, namely, the removal of geology from the domain of speculation to that of inductive science.

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