scholarly journals A First Simple Model for Periodically Self-Surging Glaciers

1975 ◽  
Vol 14 (70) ◽  
pp. 3-21 ◽  
Author(s):  
W. F. Budd
Keyword(s):  
High Speed ◽  
Natural Phenomenon ◽  
Fast Mode ◽  
Sliding Velocity ◽  
Velocity Increase ◽  
Basal Sliding ◽  
The Difference ◽  
Glacier Flow ◽  
The Given ◽  
Very High

A two-dimensional model of glacier flow is presented which includes periodical surging as a natural phenomenon for a certain class of glaciers. The input consists of the bedrock and balance profiles along the glacier, together with the ice flow properties and a frictional lubrication factor. The basal stress is determined from the condition of gross equilibrium for the whole glacier, together with the distribution of the frictional lubrication from energy dissipation along the glacier. The difference between the basal stress and the down-slope stress of the glaciers produces longitudinal strain-rates which determine the basal sliding velocity. Since the velocity is also involved in the frictional lubrication, feed-back develops between the basal stress and sliding velocity. For a given lubrication factor, a critical stage can be reached for which the velocity becomes sufficiently high to lower the basal stress, enough to cause very high velocities to develop. The model thus gives rise to three classes of glaciers with two modes of flow. “Ordinary” glaciers do not have sufficient mass flux, for the given bedrock profile, to go beyond the “slow mode” in which the basal stress and velocity increase together as the glacier builds up to steady state. “Fast” glaciers have sufficient flux to remain continuously in the “fast mode” with high velocities and relatively low basal stress. “Surging” glaciers have sufficient flux to reach the fast mode but not sufficient to maintain it, and thus develop a periodically oscillating state between the fast and slow modes with gradual build up and rapid drainage. Sample results are presented for models of a typical large valley surging glacier and for a very high-speed surging glacier.

scholarly journals A First Simple Model for Periodically Self-Surging Glaciers

1975 ◽  
Vol 14 (70) ◽  
pp. 3-21 ◽  
Author(s):  
W. F. Budd
Keyword(s):  
High Speed ◽  
Natural Phenomenon ◽  
Fast Mode ◽  
Sliding Velocity ◽  
Velocity Increase ◽  
Basal Sliding ◽  
The Difference ◽  
Glacier Flow ◽  
The Given ◽  
Very High

A two-dimensional model of glacier flow is presented which includes periodical surging as a natural phenomenon for a certain class of glaciers. The input consists of the bedrock and balance profiles along the glacier, together with the ice flow properties and a frictional lubrication factor. The basal stress is determined from the condition of gross equilibrium for the whole glacier, together with the distribution of the frictional lubrication from energy dissipation along the glacier.The difference between the basal stress and the down-slope stress of the glaciers produces longitudinal strain-rates which determine the basal sliding velocity. Since the velocity is also involved in the frictional lubrication, feed-back develops between the basal stress and sliding velocity.For a given lubrication factor, a critical stage can be reached for which the velocity becomes sufficiently high to lower the basal stress, enough to cause very high velocities to develop. The model thus gives rise to three classes of glaciers with two modes of flow.“Ordinary” glaciers do not have sufficient mass flux, for the given bedrock profile, to go beyond the “slow mode” in which the basal stress and velocity increase together as the glacier builds up to steady state.“Fast” glaciers have sufficient flux to remain continuously in the “fast mode” with high velocities and relatively low basal stress.“Surging” glaciers have sufficient flux to reach the fast mode but not sufficient to maintain it, and thus develop a periodically oscillating state between the fast and slow modes with gradual build up and rapid drainage.Sample results are presented for models of a typical large valley surging glacier and for a very high-speed surging glacier.

scholarly journals SOME APPROACHES TO THE STUDY OF CONCEPTS POLITICAL IMAGE AND NETWORK IMAGE

2020 ◽  
Vol 3 (33) ◽  
pp. 79-84
Author(s):  
L.V. Chernyshova ◽  
Keyword(s):  
Political Parties ◽  
High Speed ◽  
Modern World ◽  
The Political ◽  
Political Leader ◽  
Electoral Support ◽  
Ideological Differences ◽  
Political Conditions ◽  
The Difference ◽  
Very High

The article discusses various approaches to the study of political and network image. With the advent of modern election campaigns, it has become clear that image is an inevitable part of a successful campaign. The political image as an object of research began to appear in political science, sociological and communication studies since the 50s of the twentieth century. The political image in modern conditions is becoming such an important factor, politicians who seek to gain power or keep it must be reckoned with it. In modern socio-political conditions and the reduction of ideological differences between political parties and their leaders, their image, through which their authority is reflected, is becoming an increasingly important factor determining the difference between candidates and political parties. For the modern voter, the political image becomes more important than the ideological positions of the candidate and the party. If political parties concentrate on the “average” voter and do not show serious ideological differences, differences in election programs, the image of a political leader becomes the most important factor. Voter confidence depends on image. It is important to determine the audience for whom the political image is being created. A traditional audience is one that has long followed a particular political unit or politics as a whole. The success of the political image and the candidate depends on strategic research, which, among other things, shows what the image of the candidates should be like in these elections. The political image should be aimed at creating voters' confidence in the political leader and developing confidence in the competence of the politician, in his ability to solve pressing problems of society. The political image serves simple purposes - to “win the hearts of citizens” and mobilize their electoral support. But it is not enough to form the image of the candidate, it must be conveyed to the voter without distortion. The modern world has long entered the digital age, where information is distributed through electronic media at a very high speed. Internet technologies for the formation of a political image are beginning to become increasingly important. In the last decade, this issue has become urgent.

Design of Tail Pipes for Jet Engines-Including Reheat

1950 ◽  
Vol 54 (472) ◽  
pp. 217-234
Author(s):  
John L. Edwards
Keyword(s):  
High Speed ◽  
Heat Energy ◽  
Forward Speed ◽  
Jet Engines ◽  
Entry And Exit ◽  
High Speeds ◽  
Heated Air ◽  
Air Stream ◽  
The Difference ◽  
Very High

The principle of the ram-jet or athodyd has been understood for a number of years. It has been applied in many ways, the most prominent being the flying bomb and, rather less spectacularly, the ducted radiator. The principle is to. convert the velocity energy of a high speed air stream to pressure energy by means of a suitable duct, to apply heat energy to the compressed air, and then to expand this heated air in the form of a high velocity jet. The advantage of such a mechanism is an increase in thrust given by the product of the mass flow of air, and the difference in velocities between entry and exit; the disadvantages are, the necessity to project the duct at high forward speed before any thrust is obtained and, except at very high speeds indeed, the low thermal efficiency.

scholarly journals Surging Glaciers—The Dilemma Continues

1979 ◽  
Vol 24 (90) ◽  
pp. 502-503 ◽  
Author(s):  
M. F. Meier
Keyword(s):  
Shear Stress ◽  
Phenomenological Approach ◽  
Sliding Velocity ◽  
Recent Interest ◽  
Normal Behavior ◽  
Rapid Flow ◽  
Basal Sliding ◽  
Ice Velocity ◽  
Glacier Flow ◽  
Basal Shear

AbstractA glacier surge, according to most definitions, is a short-lived phase of unusually rapid glacier flow, after which the glacier returns to more normal behavior, with the surge–non-surge phases recurring on a regular or periodic basis. Recent interest is largely directed toward analyzing the effect of water at the bed on the periodic change in flow regime and on the rapid flow during a surge phase. For instance, study of a local depression of basal shear stress that dependson a “friction lubrication factor” which becomes important as the ice velocity increases, is one promising phenomenological approach. An important physical approach focuses on a water “collection zone” that occurs where and when the longitudinal pressure gradient in the subglacial wtaer film approaches zero. The data necessary for properly verifying these and other similar theories do not yet exist. Computer modeling of rapidly-surging glaciers based on a “friction lubrication factor” has been quite successful in duplicating their major features. Once rapid movement (102–103m a–1) has begun, sufficient water is generated at the bed, from ice melted by heat dissipated in sliding, to produce some decoupling of the glacier from its bed and to maintain the surge, but only if this water is not lost by rapid drainage. Some glaciers exhibit periodic pulses in which the basal sliding velocity during the fastest part of the pulses appears to be in the range for “normal” glaciers (<102m a–1). Some evidence suggests a continuum of behavior from steady (normal) glaciers through these “mini-surges” to classic surges. This continuum and the “mini-surges” seem to be difficult to explain quantitatively by existing theories. A few glaciers flow continuously at surging speeds (>103m a–1) in certain reaches. The up-glacier transition reaches show speeds decreasing to “nonrmal” with no indication of intermediate surging regime, but the down-glacier transition reaches may be areas where surges are triggered.

scholarly journals Wi-Fi for Affordable Broadband & 5G in Rural Areas

2021 ◽  
Author(s):  
Kishore Kumar Thakur ◽  
Ramjee Prasad
Keyword(s):  
Developing Countries ◽  
Digital Divide ◽  
Rural Areas ◽  
High Speed ◽  
Developed Countries ◽  
Digital Subscriber Line ◽  
Communication Infrastructure ◽  
The Difference ◽  
Population Ratio ◽  
Very High

The importance of Internet in our lives today cannot be overemphasized. So much so that access to Internet has been declared a fundamental right of citizens in several countries such as Finland, Spain, and Greece [1]. In most of the developed countries, high-speed Internet connectivity is enabled through wired communication infrastructure such as Fiber-to-the-Home (FTTH) and Very high bit-rate Digital Subscriber Line (VDSL). Unfortunately, the situation is not particularly encouraging in developing countries due to non-availability of such a pervasive communication infrastructure. The difference in the fiber-deployed-to-population ratio across developed and developing countries further underscores this disparity; while this ratio is 1.2 in USA, it is barely 0.1 in India [2]. Owing to this inadequacy of fiber/DSL availability, cellular access technology has emerged as the primary broadband access mechanism in developing countries. However, the penetration of cellular network is limited in rural areas as its deployment becomes unviable due to challenges such as low average revenue per user, sparse population density, and intermittent availability of electricity. This situation leaves majority of the rural people unconnected thereby creating a massive rural urban digital divide. The next generation cellular system along with the use of unlicensed Wi-Fi Technology can bridge this divide if we overcome the above-mentioned challenges. However, since the Fifth Generation (5G) cellular technology has focus on requirements such as 10 Gbps data rate, 1 ms latency, and very high speed mobility, the problems of coverage and affordability are likely to persist, further widening the digital divide [3]. This article explains how Wi-Fi is being used for affordable high speed broadband in rural areas. A successfully implemented case study of Jharkhand state is also presented, and it can be adopted as reliable business model for 5G or 5G type services in rural areas [4].

scholarly journals Surging Glaciers—The Dilemma Continues

1979 ◽  
Vol 24 (90) ◽  
pp. 502-503
Author(s):  
M. F. Meier
Keyword(s):  
Shear Stress ◽  
Phenomenological Approach ◽  
Sliding Velocity ◽  
Recent Interest ◽  
Normal Behavior ◽  
Rapid Flow ◽  
Basal Sliding ◽  
Ice Velocity ◽  
Glacier Flow ◽  
Basal Shear

AbstractA glacier surge, according to most definitions, is a short-lived phase of unusually rapid glacier flow, after which the glacier returns to more normal behavior, with the surge–non-surge phases recurring on a regular or periodic basis. Recent interest is largely directed toward analyzing the effect of water at the bed on the periodic change in flow regime and on the rapid flow during a surge phase. For instance, study of a local depression of basal shear stress that dependson a “friction lubrication factor” which becomes important as the ice velocity increases, is one promising phenomenological approach. An important physical approach focuses on a water “collection zone” that occurs where and when the longitudinal pressure gradient in the subglacial wtaer film approaches zero. The data necessary for properly verifying these and other similar theories do not yet exist. Computer modeling of rapidly-surging glaciers based on a “friction lubrication factor” has been quite successful in duplicating their major features. Once rapid movement (102–103 m a–1) has begun, sufficient water is generated at the bed, from ice melted by heat dissipated in sliding, to produce some decoupling of the glacier from its bed and to maintain the surge, but only if this water is not lost by rapid drainage. Some glaciers exhibit periodic pulses in which the basal sliding velocity during the fastest part of the pulses appears to be in the range for “normal” glaciers (<102 m a–1). Some evidence suggests a continuum of behavior from steady (normal) glaciers through these “mini-surges” to classic surges. This continuum and the “mini-surges” seem to be difficult to explain quantitatively by existing theories. A few glaciers flow continuously at surging speeds (>103 m a–1) in certain reaches. The up-glacier transition reaches show speeds decreasing to “nonrmal” with no indication of intermediate surging regime, but the down-glacier transition reaches may be areas where surges are triggered.

Comparative Analysis of Various Kinds Concrete Creep Prediction Models

2011 ◽  
Author(s):  
Jun-Qing Lei ◽  
Hang Xu ◽  
Li-Qun Zou
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Prediction Models ◽  
Concrete Creep ◽  
High Speed Railway ◽  
Railway Line ◽  
The Difference ◽  
Short Time ◽  
Very High

The ratio of bridges to High-speed Railway line in China is very high. The influence of concrete creep to bridge structure is very high, so it is necessary to study creep of concrete in depth. In this thesis, experimental data of four important regions in China are collected, and the curves of concrete creep are analyzed. While, by comparing the domestic and foreign curves of Concrete Creep Prediction Models, the difference between them could be found. In addition, the theory of long-term deformation of concrete obtained by short-time experiment, which is proposed by Professor Bazant is used. According to experimental data, the creep curves are fittd by regression method. Finally, the comparison between common prediction models and Bazants’ theory is carried out, it can be found that the regression value is closed to the measured value.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

Methodological and Sociological Analysis About The Fatwa Of Majelis Tarjih Muhammadiyah Concerning To The Muslim Marriage With An Ahl Al-Kitab

2018 ◽  
Vol 16 (2) ◽  
pp. 161
Author(s):  
Chamim Tohari
Keyword(s):  
Content Analysis ◽  
Natural Phenomenon ◽  
Research Approach ◽  
Contemporary Society ◽  
Sociological Analysis ◽  
Library Research ◽  
Empiric Data ◽  
The Law ◽  
The Difference

Relation between the different of religion comunity in the multicultural nation as in Indonesia be a natural phenomenon that it cannot be avoided. As to one of the problem that had appeared in this case is about wedding problem betweena moslem with the difference religion womans. Majority of the Indonesia religious scholars as scholar in Majelis Tarjih Muhammadiyah had been prohibiting wedding like that with various reason. while a part little of the contemporary moslem scholars have been permiting the wedding. The points which will discussed in this research is how is opinion of Majelis Tarjih Muhammadiyah about the law of wedding with the woman from Ahl Al-Kitab and its ijtihad methodology. This research should analyze the argumentation of the Majelis Tarjih that make forbidding a muslem married with the difference religion womans. This research using library research approach dan content analysis. The results of this research are: (1) Majelis Tarjih of Muhammadiyah forbidding the wedding with sad al-dzari’ah as its argumentation; (2) Majelis Tarjih’s opinion has been irrelevant because two reason, the mistake of methodology and the change of the Indonesian contemporary society (based on an empiric data). Keywords: Ahlu Kitab; Majelis Tarjih; Different Religion Marriage

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