3,642 research outputs found
Line shifts in the first overtone of DF broadened by HF
Line spectra shifts in HF and in first overtone band of DF induced by HF pressure
Helios-2 Vela-Ariel-5 gamma-ray burst source position
The gamma-ray burst of 28 January 1976, one of 18 events thus far detected in interplanetary space with Helios-2, was also observed with the Vela-5A, -6A and the Ariel-5 satellites. A small source field is obtained from the intersection of the region derived from the observed time delays between Helios-2 and Vela-5A and -6A with the source region independently found with the Ariel-5 X-ray detector. This area contains neither any steady X-ray source as scanned by HEAO-A nor any previously catalogued X-ray, radio or infrared sources, X-ray transients, quasars, seyferts, globular clusters, flare stars, pulsars, white dwarfs or high energy gamma-ray sources. The region is however, within the source field of a gamma-ray transient observed in 1974, which exhibited nuclear gamma-ray line structure
Real Time Net Zero Energy Building Energy Manager with Heterogeneous Wireless Ad hoc Network Adaptable To IoT Architectures
Significant energy consumption by buildings from utility grid has made researchers revisit existing Building Energy Management Systems (BEMS). Most of the developing countries have taken a green initiative of Net Zero Energy Buildings (NZEB) to reduce carbon foot print and fast depletion of conventional energy sources. Though the integration of solar and wind based systems to grid is successful in recent years, residential building energy management systems with renewable energy sources is still an evolving research area. Monitoring, control and actuation systems should be tightly coupled with the help of any to any device communication namely Internet of Things (IoT) to realize an efficient NZEB. In this paper a real time NZEB is proposed and developed with bi-directional wireless sensor and actuation system. Proposed NZEB central server collects and maintains a database of on site solar generation, battery state of charge and load power consumption data of a building with help of IEEE 802.15.4 and IEEE 802.11 wireless networks. Proposed system was deployed as a test bed with sensing, control, actuation and server modules and connecting them with a bi-directional wireless network architecture similar to IoT. Data observed at experimental test bed confirm that developed system can estimate on site solar power generation, state of charge on battery bank and load power consumption with negligible error. A simulation study with experimental data collected at NZEB test bed shows that NZEB can optimally schedule loads between local generation and utility grid thereby minimizing peak demand on the grid
Three precise gamma-ray burst source locations
The precise source regions of three moderately intense gamma ray bursts are derived. These events were observed with the first interplanetary burst sensor network. The optimum locations of the detectors, widely separated throughout the inner solar system, allowed for high accuracy, over-determined source fields of size 0.7 to 7.0 arc-min(2). All three locations are at fairly high galactic latitude in regions of low source confusion; none can be identified with a steady source object. Archived photographs were searched for optical transients that are able to be associated with these source fields; one such association was made
Detection of a fast, intense and unusual gamma ray transient
An unusual transient pulse of approximately 50 keV was detected by the gamma-ray burst sensor network using nine space probes and satellites. Its characteristics are unlike those of the known variety of gamma-ray bursts and therefore suggest that it was formed either by a completely different origin species or in a very different manner. It is identified with the LMC supernova remnant N49
Meteorological and extra-terrestrial causes of the daily variation of cosmic ray intensity
The daily variations of total cosmic ray intensity and the intensities of meson and electron components have been studied at Alimedabad with vertical geiger counter telescopes. The influence of meteorological factors on these variations has been examined, and it has been found that appropriate barometric coefficients for correcting the cosmic ray intensities can be obtained from a consideration of the semidiurnal components of the variations. The barometric coefficients for the three intensities are βr = -4.2% percm.Hg, βM = -2.4% percm.Hg. βK = -14.0% percm.Hg. The cosmic ray intensity variations are corrected with the appropriate coefficients for the daily variation of barometric pressure. No significant variation is then left in the electron intensity, implying that variations of this component are mostly caused by the mass absorption effect with a variation of barometric pressure. In total intensity and in meson intensity, on the other hand, there is a significant residual variation of about ·3% in amplitude. This is mainly diurnal in character with a maximum at 0900 hours I.S.T. Reasons are given for concluding that the meson residual variation is not primarily caused by either the diurnal variation of temperature in the atmosphere or of geomagnetic elements. It is finally concluded that the bulk of the meson residual diurnal variation is extra-terrestrial in origin and is caused by continuous solar emission of cosmic ray particles. This conclusion is discussed in terms of the interpretation of omnidirectional and unidirectional measurements of the diurnal variation by other workers. A connection between changes in the amplitude and the hour of maximum of the diurnal variation has been suggested
Real Time Wireless Air Pollution Monitoring system
Air pollution has
significant influence on the concentration of
constituents in the atmosphere leading to effects like global warming
and acid rains. To avoid such adverse imbalances in the nature, an
air pollution monitoring system is utmost important. This paper
attempts
to develop an effective solution for pollution monitoring
using wireless sensor networks (WSN) on a real time basis namely
real time wireless air pollution monitoring system. Commercially
available discrete gas sensors for sensing concentration of gases l
ike
CO
2
, NO
2,
CO and O
2
are calibrated using appropriate calibration
technologies. These pre
-
calibrated gas sensors are then integrated
with the wireless sensor motes for field deployment at the campus and
the Hyderabad city using multi hop data aggregatio
n algorithm. A
light weight middleware and a web interface to view the live pollution
data in the form of numbers and charts from the test beds was
developed and made available from anywhere on the internet. Other
parameters like temperature and humidity w
ere also sensed along
with gas concentrations to enable data analysis through data fusion
techniques. Experimentation carried out using the developed wireless
air pollution monitoring system under different physical conditions
show that the system collects
reliable source of real time fine
-
grain
pollution data
PCA Encrypted Short Acoustic Data Inculcated in Digital Color Images
We propose develop a generalized algorithm for hiding audio signal using image steganography. The authors suggest transmitting short audio messages camouflaged in digital images using Principal Component Analysis (PCA) as an encryption technique. The quantum of principal components required to represent the audio signal by removing the redundancies is a measure of the magnitude of the Eigen values. The aforementioned technique follows a dual task of encryption and in turn also compresses the audio data, sufficient enough to be buried in the image. A 57Kb audio signal is decipher from the Stego image with a high PSNR of 47.49 and a correspondingly low mse of 3.3266 × 1
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