Experimental tests of the mechanism of radio emission from showers

1968 ◽  
Vol 46 (10) ◽  
pp. S230-S233 ◽  
Author(s):  
F. G. Smith ◽  
A. D. Bray ◽  
R. A. Porter ◽  
W. S. Torbitt ◽  
J. V. Jelley
Keyword(s):  
Radio Emission ◽  
Geomagnetic Field ◽  
Experimental Tests ◽  
Excess Charge ◽  
The North ◽  
Dip Angle ◽  
East West

It is expected that the geomagnetic field will separate the shower particles of opposite signs, giving radiation which shows an east–west polarization. This has been tested by using crossed dipoles, and by searching for the expected asymmetry in the north–south plane due to the dip angle of the field. No evidence for geomagnetic separation has been found, and it is concluded that the excess charge must be greater than had previously been assumed.

Latitudinally propagating on–off switching aurorae and associated geomagnetic pulsations: A case study of an event of February 20, 1980

1981 ◽  
Vol 59 (8) ◽  
pp. 1131-1136 ◽  
Author(s):  
T. Oguti ◽  
S. Kokubun ◽  
K. Hayashi ◽  
K. Tsuruda ◽  
S. Machida ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Auroral Zone ◽  
Geomagnetic Pulsations ◽  
The North ◽  
Field Fluctuations ◽  
Auroral Latitude ◽  
East West

Poleward propagating on–off switching aurorae and equatorward propagating aurorae, otherwise similar, were observed simultaneously at Rabbit Lake and La Ronge, respectively, for about 40 min before dawn of Feb. 20, 1980. Rabbit Lake is a high auroral latitude site, at the northern end of the Saskatchewan chain of stations for the Pulsating Aurora Campaign, whereas La Ronge, due south of Rabbit, is almost at the southern edge of the auroral zone. The repetition periods of the on–off switching aurorae are about 6 to 13 s. The poleward propagating aurorae had well defined fronts of light which extended a few hundred kilometres or more in the east–west direction. The light fronts of the equatorward propagating aurorae, though comparable in extent, were less well defined: they were thicker and fuzzier. The poleward propagating aurorae moved with a speed ~10 km/s whereas the equatorward ones did so with a slightly greater velocity. Geomagnetic field fluctuations were concurrent with the aurorae at both sites. At Rabbit Lake, northward (southward) field changes were associated with upward (downward) changes whereas the trend is reversed at La Ronge, viz., northward (southward) changes with downward (upward) changes. These trends are consistent with a model of a periodic occurrence of two line currents, westward and eastward, the former moving poleward north of Rabbit Lake and the latter approaching La Ronge from the north.

scholarly journals Analysis of Aeromagnetic Anomalies of the North-eastern Nigerian part of the Chad Basin

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Kehinde Ishola ◽  
Blessing Okoye ◽  
Lukumon Adeoti ◽  
Kayode Oyedele
Keyword(s):  
Geomagnetic Field ◽  
Fourier Transformation ◽  
Magnetic Anomalies ◽  
Aeromagnetic Data ◽  
The North ◽  
Spectral Technique ◽  
North Eastern ◽  
Anomaly Map ◽  
East West

An appraisal of aeromagnetic data lying between Longitudes 110 00' 25.95''E - 110 30’ 15.1”E and Latitudes 110 30’ 7.59”N – 120 05’ 45.6''N has been carried out with a view to understanding structural trends of interest as well as determination of depth to magnetic sources giving rise to magnetic anomalies in the study area. To achieve the objectives of this study, the datasets were digitized along contours, corrected for the main geomagnetic field, re-gridded, and merged to generate magnetic structural anomaly map of the area. Also, from the aeromagnetic data, we used spectral technique based on Fourier transformation to estimate depths along some selected profiles on the residual anomaly map. The results show that the most pronounced structures are observed towards the southern and central parts of the study area signifying that majority of the magnetic anomalies trend in the Northeast-Southwest while the minor ones trend East-West direction. This suggests that the study area is intensely fractured with major regional faulting systems playing important role in entrapment and exploration of natural resources as well as understanding the hydrogeologic framework of the basin. The spectral analysis shows mainly two depth magnetic sources, the deeper sources with depths in the range of 1.34 to 3.42 km while the shallow sources are observed at depths between 0.33 to 0.91 km. Aeromagnetic data analysis over the basin shows that prominent anomalies have been identified and located.

scholarly journals A Low frequency Southern Sky Survey Using the Mauritius Radio Telescope

2002 ◽  
Vol 199 ◽  
pp. 25-31
Author(s):  
N. Udaya Shankar
Keyword(s):  
Radio Telescope ◽  
Low Frequency ◽  
Fourier Synthesis ◽  
North East ◽  
The North ◽  
Sky Survey ◽  
Correlation Receiver ◽  
Complex Correlation ◽  
Right Ascension ◽  
East West

The Mauritius Radio Telescope (MRT) is a Fourier synthesis instrument which has been built to fill the gap in the availability of deep sky surveys at low radio frequencies in the southern hemisphere. It is situated in the north-east of Mauritius at a southern latitude of 20°.14 and an eastern longitude of 57°.73. The aim of the survey with the MRT is to contribute to the database of southern sky sources in the declination range −70° ≤ δ ≤ −10°, covering the entire 24 hours of right ascension, with a resolution of 4' × 4'.6sec(δ + 20.14°) and a point source sensitivity of 200 mJy (3σ level) at 151.5 MHz.MRT is a T-shaped non-coplanar array consisting of a 2048 m long East-West arm and a 880 m long South arm. In the East-West arm 1024 fixed helices are arranged in 32 groups and in the South arm 16 trolleys, with four helices on each, which move on a rail are used. A 512 channel, 2-bit 3-level complex correlation receiver is used to measure the visibility function. At least 60 days of observing are required for obtaining the visibilities up to the 880 m spacing. The calibrated visibilities are transformed taking care of the non-coplanarity of the array to produce an image of the area of the sky under observation.This paper will describe the telescope, the observations carried out so far, a few interesting aspects of imaging with this non-coplanar array and present results of a low resolution survey (13' × 18') covering roughly 12 hours of right ascension, and also present an image with a resolution of 4' × 4'.6sec(δ + 20.14°) made using the telescope.

scholarly journals Optimal design of the solar tracking system of parabolic trough concentrating collectors

2020 ◽  
Vol 15 (4) ◽  
pp. 613-619
Author(s):  
Li Kong ◽  
Yunpeng Zhang ◽  
Zhijian Lin ◽  
Zhongzhu Qiu ◽  
Chunying Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Tracking System ◽  
Low Cost ◽  
Parabolic Trough ◽  
The North ◽  
Tracking Mode ◽  
Solar Tracking ◽  
East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

The mineralogical composition of some Scottish soils

1925 ◽  
Vol 15 (3) ◽  
pp. 257-271 ◽  
Author(s):  
James Hendrick ◽  
George Newlands
Keyword(s):  
Mineralogical Composition ◽  
Fine Sand ◽  
Plant Food ◽  
Sand Fraction ◽  
Extensive Survey ◽  
North East ◽  
The North ◽  
Local Origin ◽  
East West ◽  
Made In

1. Previous investigations showed that certain Scottish soils were of glacial drift origin, that they were comparatively rich in unweathered silicates and therefore in reserves of plant-food, that they showed considerable variation in such silicates and were capable of classification accordingly. Some indication was also shown that the glacial drift, and hence the resulting soil, was sometimes of local origin, its character being determined by the underlying rock. In the present investigation a more extensive survey of Scottish soils has been made in order to discover to what extent these preliminary findings might be applicable generally.2. For this purpose soils have been collected from various localities in the north, north-east, west and south of Scotland, and have been analysed mechanically and the “fine sand” fraction examined mineralogically.

scholarly journals Monitoring and Analysis of Dynamic Characteristics of Super High-rise Buildings using GB-RAR: A Case Study of the WGC under Construction, China

2020 ◽  
Vol 10 (3) ◽  
pp. 808 ◽  
Author(s):  
Lv Zhou ◽  
Jiming Guo ◽  
Xuelin Wen ◽  
Jun Ma ◽  
Fei Yang ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Dynamic Characteristics ◽  
Horizontal Displacement ◽  
Dynamic Monitoring ◽  
High Rise ◽  
The North ◽  
Study Results ◽  
Under Construction ◽  
East West

Accurate dynamic characteristics of super high-rise buildings serve as a guide in their construction and operation. Ground-based real aperture radar (GB-RAR) techniques have been applied in monitoring and analyzing the dynamic characteristics of different buildings, but only few studies have utilized them to derive the dynamic characteristics of super high-rise buildings, especially those higher than 400 m and under construction. In this study, we proposed a set of technical methods for monitoring and analyzing the dynamic characteristics of super high-rise buildings based on GB-RAR and wavelet analysis. A case study was conducted on the monitoring and analysis of the dynamic characteristics of the Wuhan Greenland Center (WGC) under construction (5–7 July 2017) with a 636 m design height. Displacement time series was accurately derived through GB-RAR and wavelet analysis, and the accuracy reached the submillimeter level. The maximum horizontal displacement amplitudes at the top of the building in the north–south and east–west directions were 18.84 and 15.94 mm, respectively. The roof displacement trajectory of the WGC was clearly identified. A certain negative correlation between the temperature and displacement changes at the roof of the building was identified. Study results demonstrate that the proposed method is effective for the dynamic monitoring and analysis of super high-rise buildings with noninvasive and nondestructive characteristics.

scholarly journals Comparison of Buoy-Mounted and Bottom-Moored ADCP Performance at Gray’s Reef

2007 ◽  
Vol 24 (2) ◽  
pp. 270-284 ◽  
Author(s):  
Harvey E. Seim ◽  
Catherine R. Edwards
Keyword(s):  
High Frequency ◽  
Major Axis ◽  
National Data ◽  
Noise Floor ◽  
The North ◽  
Experimental Configuration ◽  
Adcp Measurements ◽  
Adcp Data ◽  
Adcp Observations ◽  
East West

Abstract Simultaneous ADCP profile measurements are compared over a 2-month period in late 2003. One set of measurements comes from a National Data Buoy Center (NDBC) buoy-mounted ADCP, the other from a bottom-mounted, upward-looking ADCP moored roughly 500 m from the buoy. The study was undertaken to evaluate the proficiency of an experimental configuration by NDBC; unfortunately, the ADCP was not optimally configured. The higher temporally and vertically resolved bottom-mounted ADCP data are interpolated in time and depth to match the buoy-mounted ADCP measurements. It is found that the two ADCP measurements are significantly different. The buoy-mounted measurements are affected by high-frequency (<10 h period) noise that is vertically coherent throughout the profiles. This noise results in autospectra that are essentially white, unlike the classic red spectra formed from the bottom-mounted ADCP observations. The spectra imply a practical noise floor of 0.045 m s−1 for the buoy-mounted system. Contamination by surface waves is the likely cause of this problem. At tidal frequencies the buoy-mounted system underestimates major axis tidal current magnitude by 10%–40%; interference from the buoy chain and/or fish or plankton are considered the most likely cause of the bias. The subtidal velocity field (periods greater than 40 h) is only partially captured; the correlation coefficient for the east–west current is 0.49 and for the north–south current is 0.64.

scholarly journals The Historical and Psychological Significance of the Unorganized Games of New Zealand Primary School Children

2021 ◽  
Author(s):  
◽  
Brian Sutton-Smith
Keyword(s):  
New Zealand ◽  
Primary School ◽  
Small Group ◽  
School Children ◽  
Primary School Children ◽  
The North ◽  
Psychological Significance ◽  
East And West ◽  
Recurrent Motifs ◽  
East West

<p>In the Spring of 1948 while teaching at a primary school, I observed a small group of girls playing a game called "Tip the Finger". During the game one of the players chanted the following rhyme: "Draw a snake upon your back And this is the way it went North, South, East, West, Who tipped your finger?" I recognized immediately and with some surprise that this rhyme contained elements which were not invented by the children and were probably of some antiquity. I knew, for example, though only in a vague and unlearned manner, that the four pattern of the North, South, East and West and the Snake symbolism were recurrent motifs in mythology and folklore. I was aware also that there did not exits any specialized attempt to explain the part that games of this nature played in the lives of the players.</p>

scholarly journals EVOLUTION OF KARAKORAM SEQUENCE, HUNZA VALLEY NE PAKISTAN: EVIDENCES FROM FIELD MAPPING AND MICRO-ANALYTICAL WORK

2020 ◽  
Vol 5 ◽  
pp. 19
Author(s):  
S. S. Baig ◽  
C. Xue ◽  
Masroor Alam ◽  
Naeem Ullah ◽  
M. Alam ◽  
...  
Keyword(s):  
Geological Mapping ◽  
Central Portion ◽  
High Grade ◽  
Metamorphic Complex ◽  
Field Mapping ◽  
The North ◽  
Analytical Work ◽  
History Of ◽  
Micro Analysis ◽  
East West

The Karakoram metamorphic Complex (KMC) in the southern Karakoram block is one of the best examples of Barrovian type metamorphism that comprises numerous exhumed metapelite units where a series of low to high grade (green schist to sillimanite facie) rocks are exposed. This sequence shows a complex polyphase history of metamorphism and deformation which offer deeper understanding of collision orogeny. Karakoram metamorphic Complex contains metapelites, meta-carbonates, meta-igneous and amphibolite layers, cross-cut by granite sheets in the northern part. This complex is bounded to the north by the Hunza plutonic unit which is the central portion of the massive east-west trending Karakoram axial batholith and to the southwest by the Main Karakoram thrust (MKT). In this contribution, we provide detail geological mapping, petrography, geochemistry and micro-analytical work using Electron Prob-micro analysis in the central Hunza Valley.

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