scholarly journals Determining critical areas of transmission towers due to sudden removal of members

2017 ◽  
Vol 9 ◽  
pp. 138-147 ◽  
Author(s):  
Soheil Dadras Eslamlou ◽  
Behrouz Asgarian
Keyword(s):  
Critical Areas ◽  
Transmission Towers

“High Resolution High Voltage Electron Microscopy”

1968 ◽  
Vol 26 ◽  
pp. 326-327
Author(s):  
Benjamin M. Siegel
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Voltage ◽  
Full Potential ◽  
Contrast Imaging ◽  
High Voltage Electron Microscopy ◽  
Low Contrast ◽  
Voltage Electron ◽  
Critical Areas ◽  
High Voltage Electron

The potential advantages of high voltage electron microscopy for extending the limits of resolution and contrast in imaging low contrast objects, such as biomolecular specimens, is very great. The results of computations will be presented showing that at accelerating voltages of 500-1000 kV it should be possible to achieve spacial resolutions of 1 to 1.5 Å and using phase contrast imaging achieve adequate image contrast to observe single atoms of low atomic number.The practical problems associated with the design and utilization of the high voltage instrument are, optimistically, within the range of competence of the state of the art. However, there are some extremely important and critical areas to be systematically investigated before we have achieved this competence. The basic electron optics of the column required is well understood, but before the full potential of an instrument capable of resolutions of better than 1.5 Å are realized some very careful development work will be required. Of great importance for the actual achievement of high resolution with a high voltage electron microscope is the fundamental limitation set by the characteristics of the high voltage electron beam that can be obtained from the accelerator column.

Sociological dimension of economic globalization: world trends and Ukrainian realities (Second part. Social changes in Ukrainian society in the context of economic globalization)

2020 ◽  
pp. 68-110
Author(s):  
Tetiana Petrushyna ◽  
Anatolii Arseienko
Keyword(s):  
Economic Globalization ◽  
Division Of Labour ◽  
Social Consequences ◽  
Social Discourse ◽  
Social Changes ◽  
Significant Deterioration ◽  
Global Competitiveness ◽  
Critical Areas ◽  
Systemic Crisis ◽  
Ukrainian Society

Globalization remains the most common and quite controversial concept in modern social discourse. Within the theoretical and conceptual sociological dimension, the authors analyzed the essence of economic globalization (EG) as its defining type. They studied globalization as an objective process (first of all, the international division of labour) and the subjective process of forming a global capitalist economy under the auspices of leading Western countries, supranational financial and economic institutions (primarily the World Bank and the IMF), TNCs. As the main drivers of globalization, they determine its forms and directions in the interests of the "core" of global capitalism. Within the empirical sociological dimension of EG (which involves measuring the various manifestations of the EG process itself as well as its social consequences), the authors paid particular attention to the analysis of social changes in Ukrainian society. The capitalization of the Ukrainian economy, which took place in parallel with Ukraine’s entry into the global economic space, led to degradation of the national economy, significant deterioration of living standards of most citizens, creation of anti-social state with the systemic crisis as its main attribute. To prove these conclusions, the authors analyzed the dynamics of the principal macroeconomic and sociological indicators of Ukrainian society’s life for almost 30 years of drift to the roadside of the global capitalist world, based on the study of numerous domestic and foreign sources. The authors focused on the research of eight critical areas of social changes: deindustrialization of the economy, global competitiveness and innovation, GDP dynamics, employment, income and welfare of the population, socioeconomic inequality, debt dependence and degradation of Ukrainian science. The analysis shows the need to abandon the neoliberal paradigm of development and search for the alternative and more fair models of EG.

INNOVATIVE SOLUTIONS FOR MONITORING OF LANDSLIDE CRITICAL AREAS

2010 ◽  
Vol 9 (4) ◽  
pp. 479-481
Author(s):  
Ioan Craciun ◽  
Catrinel-Raluca Giurma-Handley ◽  
Ion Giurma ◽  
Marius Telisca
Keyword(s):  
Critical Areas ◽  
Innovative Solutions

Use of hybrid shots in planning Perfexion Gamma Knife treatments for lesions close to critical structures

2008 ◽  
Vol 109 (Supplement) ◽  
pp. 34-40 ◽  
Author(s):  
Paula L. Petti ◽  
David A. Larson ◽  
Sandeep Kunwar
Keyword(s):  
Optic Nerve ◽  
Gamma Knife ◽  
Pituitary Tumor ◽  
Metastatic Lesion ◽  
Conformity Index ◽  
Target Coverage ◽  
Critical Areas ◽  
Planning Technique ◽  
Small Targets ◽  
Critical Structure

Object The authors investigated the use of different collimator values in different sectors (hybrid shots) when treating patients with lesions close to critical structures with the Perfexion model Gamma Knife. Methods Twelve patients with various tumors (6 with a pituitary tumor, 3 with vestibular schwannoma, 2 with meningioma, and 1 with metastatic lesion) that were within 4 mm of the brainstem, optic nerve, pituitary stalk, or cochlea were considered. All patients were treated at the authors' institution between June 2007 and March 2008. The patients' treatments were replanned in 2 different ways. In the first plan, hybrid shots were used such that the steepest dose gradient was aligned with the junction between the target and the critical structure(s). This was accomplished by placing low-value collimators in appropriate sectors. In the second plan, no hybrid shots were used. Sector blocking (either manual or dynamic) was required for all plans to reduce the critical structure doses to acceptable levels. Prescribed doses ranged from 12 to 30 Gy at the periphery of the target. The plans in each pair were designed to be equally conformal in terms of both target coverage (as measured by the Paddick conformity index) and critical structure sparing. Results The average number of shots required was roughly the same using either planning technique (16.7 vs 16.6 shots with and without hybrids). However, for all patients, the number of blocked sectors required to protect critical areas was larger when hybrid shots were not used. On average, nearly twice as many blocked sectors (14.8 vs 7.0) were required for the plans that did not use hybrid shots. The number of high-value collimators used in each plan was also evaluated. For small targets (≤ 1 cm3), for which 8 mm was considered a high value for the collimator, plans employing hybrids used an average of 2.3 times as many 8-mm sectors as did their nonhybrid counterparts (7.4 vs 3.2 sectors). For large targets (> 1 cm3), for which 16 mm was considered a high value for the collimator, hybrid plans used an average of 1.4 times as many 16-mm sectors as did the plans without hybrids (10.7 vs 7.7 sectors). Decreasing the number of blocked sectors and increasing the number of high-value collimator sectors led to use of shorter beam-on times. Beam-on times were 1–39% higher (average 17%) when hybrid shots were not allowed. The average beam-on time for plans with and without hybrid shots was 67.4 versus 78.4 minutes. Conclusions The judicious use of hybrid shots in patients for whom the target is close to a critical structure is an efficient way to achieve conformal treatments while minimizing the beam-on time. The reduction in beam-on time with hybrid shots is attributed to a reduced use of blocked sectors and an increased number of high-value collimator sectors.

scholarly journals Symmetry Analysis of Oriental Polygonal Pagodas Using 3D Point Clouds for Cultural Heritage

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1228
Author(s):  
Ting On Chan ◽  
Linyuan Xia ◽  
Yimin Chen ◽  
Wei Lang ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Unmanned Aerial Vehicle ◽  
Point Cloud ◽  
Geometric Model ◽  
Digital Camera ◽  
Point Clouds ◽  
Symmetry Analysis ◽  
3D Point Clouds ◽  
Transmission Towers ◽  
Aerial Vehicle

Ancient pagodas are usually parts of hot tourist spots in many oriental countries due to their unique historical backgrounds. They are usually polygonal structures comprised by multiple floors, which are separated by eaves. In this paper, we propose a new method to investigate both the rotational and reflectional symmetry of such polygonal pagodas through developing novel geometric models to fit to the 3D point clouds obtained from photogrammetric reconstruction. The geometric model consists of multiple polygonal pyramid/prism models but has a common central axis. The method was verified by four datasets collected by an unmanned aerial vehicle (UAV) and a hand-held digital camera. The results indicate that the models fit accurately to the pagodas’ point clouds. The symmetry was realized by rotating and reflecting the pagodas’ point clouds after a complete leveling of the point cloud was achieved using the estimated central axes. The results show that there are RMSEs of 5.04 cm and 5.20 cm deviated from the perfect (theoretical) rotational and reflectional symmetries, respectively. This concludes that the examined pagodas are highly symmetric, both rotationally and reflectionally. The concept presented in the paper not only work for polygonal pagodas, but it can also be readily transformed and implemented for other applications for other pagoda-like objects such as transmission towers.

scholarly journals Effect of Earthing Enhancing Compound (EEC) on Improving Tower Footing Resistance of a 500 kV Tower in a Rocky Area

2021 ◽  
Vol 11 (12) ◽  
pp. 5623
Author(s):  
Nur Alia Farina Mohd Nasir ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Miszaina Osman ◽  
Muhamad Safwan Abd Rahman ◽  
Ungku Anisa Ungku Amirulddin ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Comparative Analysis ◽  
Transmission Line ◽  
Structure Analysis ◽  
Current Distribution ◽  
Soil Profile ◽  
Soil Structure ◽  
Soil Resistivity ◽  
Transmission Towers ◽  
Rocky Soil

This paper presents a comparative analysis of different earthing designs’ performances, with particular interest on the use of earthing enhancing compound (EEC) for a selected earthing design of 500 kV transmission towers in a rocky soil, using the SESCAD tool of the Current distribution, electromagnetic field grounding and soil structure analysis (CDEGS) software. The simulation included the interpretation of soil profile and comparison between designs A, B and C, which are currently used for the 500 kV tower footing resistance (TFR) improvement. Results showed each design had reduced the TFR by 66%, 54.7% and 63.2% for the towers T42, T48 and T50, respectively. In some cases, further improvement of TFR is required, especially in the rocky area where the soil resistivity (SR) value is of more than 500 Ω⋅m. In this case, EEC was used in Design C, encasing both the vertical and horizontal electrodes, and it reduced the TFR further by 16% to 20%. The characteristics of the soil and earthing arrangement design play an important role in achieving a low TFR value, which is directly proportional to the backflashover occurrence and thus to the transmission line performance.

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