scholarly journals Radio refractivity observations over the oceans using airborne microwave refractometer in tropics

MAUSAM ◽  
2021 ◽  
Vol 42 (2) ◽  
pp. 183-186
Author(s):  
S. B. S. S. SARMA
Keyword(s):  
Coastal Waters ◽  
Layer Structure ◽  
National Physical Laboratory ◽  
New Delhi ◽  
Physical Laboratory ◽  
Antisubmarine Warfare ◽  
Time Basis ◽  
Anomalous Propagation ◽  
First Time ◽  
Marine Layer

The coastal waters of Indian sub -continent do not have reliable measurements of fine structure of radio refractivity especially in near real-time basis needed to mitigate the effects of anomalous propagation for the defence communications as well as for antisubmarine warfare. This programme was designed to document the radio refractive layer structure and variations of the marine layer in tropical waters of India. The paper describes the above observations taken using the airborne microwave refractometer developed by the author at National Physical Laboratory, New Delhi. Typical observations taken (for the first time in India) under normal and anomalous propagation conditions are presented and the results are compared with the special shipborne observations made under MONEX operation over the coastal waters of India.

Josephson voltage standard at National Physical Laboratory, New Delhi

Pramana ◽  
1987 ◽  
Vol 28 (5) ◽  
pp. 517-527 ◽  
Author(s):  
A K Gupta ◽  
N S Natarajan ◽  
V S Tomar ◽  
N D Kataria ◽  
V K Batra ◽  
...  
Keyword(s):  
National Physical Laboratory ◽  
New Delhi ◽  
Voltage Standard ◽  
Physical Laboratory

A new absolute determination of the acceleration due to gravity at the National Physical Laboratory, England

1967 ◽  
Vol 261 (1120) ◽  
pp. 211-252 ◽  
Keyword(s):  
National Physical Laboratory ◽  
Atomic Unit ◽  
Time Intervals ◽  
Gravity Station ◽  
Absolute Determination ◽  
Physical Laboratory ◽  
Air Resistance ◽  
Definition Of ◽  
First Time

A new absolute determination of the acceleration due to gravity at the National Physical Laboratory has been made by timing the symmetrical free motion of a body moving under the attraction of gravity; it is the first time this method has been used. The moving body was a glass ball and it was timed at its passage across two horizontal planes by the flashes of light that it produced when it passed between two horizontal slits which served to define each plane optically, the ball focusing light from one of the slits, which was illuminated, upon the other slit which had a photomultiplier placed behind it. The separation of the two planes defined by the pairs of slits was measured interferometrically and referred directly to the international wavelength definition of the metre, while the time intervals were measured in terms of the atomic unit of time scale A l. The value of gravity as reduced to the British Fundamental Gravity Station in the N. P. L. is 981 181.75 mgal, s.d. 0.13 mgal (1 mgal = 10 -5 m/s 2 ). Systematic errors, are believed to be very small; this is particularly true of the error due to air resistance. The main contribution to the observed scatter of the results comes from microseismic disturbances. The new result is 1.4 mgal less than that obtained at the fundamental station by J. S. Clark (1939) using a reversible pendulum . It is very close to the mean of a number of recent absolute determinations by other methods, but this may not be very significant because the uncertainties of those determinations and of the comparisons between the sites at which they were made and the present site are not less than 5 times the standard deviation of the new result.

scholarly journals Detection of Kelvin-Helmholtz billows over the National Capital Region of India using SODAR

2021 ◽  
Author(s):  
Nishant Kumar ◽  
Kirti Soni ◽  
Ravinder Agarwal
Keyword(s):  
Boundary Layer ◽  
National Physical Laboratory ◽  
New Delhi ◽  
National Capital Region ◽  
Resolution Limit ◽  
Capital Region ◽  
Physical Laboratory ◽  
Sound Detection ◽  
National Capital ◽  
Remote Sensing Methods

Abstract. Kelvin-Helmholtz billows (KHB) have been investigated in the Atmospheric Boundary layer (ABL) using Mono-static SODAR (Sound Detection And Ranging) designed and developed by CSIR-National Physical Laboratory, New Delhi over the capital region Delhi of India. KH billows are a primary cause of mixing in stably stratified conditions and hence have been studied widely by researchers by using ground-based and remote sensing methods. About ninety cases of KHBs observed in SODAR echograms from March 2019 to November 2019 in the ABL. Trains of K-H billows lasting from thirty minutes to various minutes were frequently detected in the lower portion of the troposphere (ABL), creating in a statically stable ABL. Most recognised billows are round the resolution limit of SODAR. Additionally, several of the cases contain billows with extremely varied amplitudes and shapes. The most significant number of episodes observed in the October months were related with the morning growth of the inversion.

ANALYSIS OF THE FUNCTIONING OF MARINE ECOSYSTEMS ON CHANGING THE PARAMETERS OF THE BIOLUMINESCENCE FIELD ON THE CRIMEAN BLACK SEA SHELF

2017 ◽  
Author(s):  
Svetlana Rubtsova ◽  
Svetlana Rubtsova ◽  
Natalya Lyamina ◽  
Natalya Lyamina ◽  
Aleksey Lyamin ◽  
...  
Keyword(s):  
Black Sea ◽  
Field Intensity ◽  
Deep Water ◽  
Coastal Waters ◽  
Integrated Management ◽  
Abiotic Factors ◽  
Environmental Safety ◽  
The Black Sea ◽  
Intensity Increase ◽  
First Time

The concept of a new approach to environmental assessment is offered in the system of integrated management of the resource and environmental safety of the coastal area of the Black Sea. The studies of the season and daily changeability in the bioluminescence field in the Sevastopol coastal waters has been conducted. For the first time considerable differences in the bioluminescence field seasonal changes in the surface and deep water layers and the reasons conditioning this phenomenon have been shown, using a method of multidimensional statistical analysis. The bioluminescence field vertical profile change in the Black sea coastal waters in the autumn period at night has been studied. It has been shown that according to the character of bioluminescence parameters dynamics a water column can be divided into layers: upper (0 – 35 m) and deep water (36 – 60 m). It has been revealed that life rhythms of the plankton community are the main reason for the bioluminescence field intensity variability. It has been revealed that 14-hour periodicity of the bioluminescence field is related to the changes in light and its variations with 2,5…4,5 hours are conditioned by planktonts endogenous daily rhythms. And here biotic factors effect mostly periodicity of the bioluminescence field intensity increase and fall down at the dark time of the day. Abiotic factors are of less importance in circadian rhythmic of the bioluminescence field in the neritic zone.

scholarly journals 75th Foundation Day of CSIR-National Physical Laboratory: Celebration of Achievements in Metrology for National Growth

MAPAN ◽  
2021 ◽  
Author(s):  
Sanjay Yadav ◽  
Goutam Mandal ◽  
V. K. Jaiswal ◽  
D. D. Shivagan ◽  
D. K. Aswal
Keyword(s):  
National Physical Laboratory ◽  
Physical Laboratory ◽  
National Growth

scholarly journals First Report of blaNDM-1 Bearing IncX3 Plasmid in Clinically Isolated ST11 Klebsiella pneumoniae from Pakistan

2021 ◽  
Vol 9 (5) ◽  
pp. 951
Author(s):  
Hazrat Bilal ◽  
Gaojian Zhang ◽  
Tayyab Rehman ◽  
Jianxion Han ◽  
Sabir Khan ◽  
...  
Keyword(s):  
Sequence Type ◽  
The Other ◽  
High Rate ◽  
Antibiotics Resistance ◽  
New Delhi ◽  
Molecular Type ◽  
Plasmid Analysis ◽  
First Time ◽  
Encoding Genes ◽  
Sequence Types

The New Delhi Metallo-β-lactamase (NDM) is among the most threatening forms of carbapenemases produced by K. pneumoniae, well-known to cause severe worldwide infections. The molecular epidemiology of blaNDM-1-harboring K. pneumoniae is not well elucidated in Pakistan. Herein, we aim to determine the antibiotics-resistance profile, genes type, molecular type, and plasmid analysis of 125 clinically isolated K. pneumoniae strains from urine samples during July 2018 to January 2019 in Pakistan. A total of 34 (27.2%) K. pneumoniae isolates were carbapenemases producers, and 23 (18.4%) harbored the blaNDM-1 gene. The other carbapenemases encoding genes, i.e., blaIMP-1 (7.2%), blaVIM-1 (3.2%), and blaOXA-48 (2.4%) were also detected. The Multi Locus Sequence Typing (MLST) results revealed that all blaNDM-1-harboring isolates were ST11. The other sequence types detected were ST1, ST37, and ST105. The cluster analysis of Xbal Pulsed Field Gel Electrophoresis (PFGE) revealed variation amongst the clusters of the identical sequence type isolates. The blaNDM-1 gene in all of the isolates was located on a 45-kb IncX3 plasmid, successfully transconjugated. For the first time, blaNDM-1-bearing IncX3 plasmids were identified from Pakistan, and this might be a new primary vehicle for disseminating blaNDM-1 in Enterobacteriaceae as it has a high rate of transferability.

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