R. K. Rai

Bio: R. K. Rai is an academic researcher from Council of Scientific and Industrial Research. The author has contributed to research in topics: Superalloy & Deformation (engineering). The author has an hindex of 8, co-authored 28 publications receiving 202 citations. Previous affiliations of R. K. Rai include Indian Institute of Science & Malaviya National Institute of Technology, Jaipur.

Yield attributes, yield and quality of soybean (Glycine max) as influenced by integrated nutrient management

Abstract: A field experiment was conducted during the rainy season of 2000 and 2001 at the Indian Agricutlural Research Institute, New Delhi, to study the effect of integrated nutrient management in soybean [Glycine max (L.) Merr.] on its yield attributes, seed yield and quality attributes. The treatments included recommended rate of NPK fertilizers alone or in combination with zinc @ 25 kg ZnSO4/ha or FYM @ 5 tonnes/ha or biofetilizers or wheat (Triticum aestivum L. emend. Fiori & Paol.) residue incorporation @ 5 tonnes/ha. The application of recommended level of NPK with FYM and biofertilizers showed superiority for pods/plant, seeds/pod, 100-seed weight, seed yield, protein and oil content in soybean seed over the sole application of recommended NPK level. The combined application of NPK + FYM + biofertilizer recorded the highest number of pods/plant (38.45 and 37.89), seeds/pod (2.90 and 2.87) and 100-seed weight of soybean during 2000 and 2001 respectively. The highest protein content was recorded in treatment receiving NPK + FYM + crop residue (39.43 and 38.12% in 2000 and 2001 respectively), while the highest oil content in treatment receiving NPK+FYM + BF.

Effect of electrojet on the total electron content of the ionosphere over the Indian subcontinent

Abstract: THE radio beacon method of measuring TEC along a chain of optimally spaced stations near the equatorial anomaly has been used to monitor continuously the latitudinal extent of the anomaly. Comparisons with the magnitude of the electrojet show a clear dependence of anomaly strength upon the electrojet intensity with an approximate two-hour time delay.

High temperature tensile deformation of a directionally solidified nickel base superalloy: Role of micro constituents

Abstract: High temperature tensile deformation behaviour of directionally solidified nickel base superalloy CM 247 DS was studied by conducting tensile tests in the temperature range 25–955 °C and extensive electron microscopic examinations to understand the influence of different phases on tensile behaviour. Micro-constituents, especially carbides and γ−γ′ eutectics influence the deformation and fracture behaviour of alloy CM 247 DS. Cracking of carbide precipitates was extensively observed during tensile deformation at 25 °C. However, tendency of carbide cracking decreased and more carbide-matrix interface de-bonding were observed with increase in test temperature.

Storms in the ionosphere: Patterns and processes for total electron content

Abstract: [1] The ionosphere's total electron content (TEC) is a parameter widely used in studies of the near-Earth plasma environment. The scientific use of TEC appeared early in the artificial satellite era, and among its many contributions were fundamental insights into how the ionosphere responds to geomagnetic storms. While many excellent reviews of solar-terrestrial disturbances exist in the literature, none have concentrated on the TEC parameter per se. With new TEC data sets increasingly available from the Global Positioning System (GPS), a comprehensive summary of pre-GPS storm studies is needed to set the base for progress in the GPS era. This review summarizes past case studies, describes statistical occurrence pattern, and identifies responsible mechanisms validated via modeling. It presents a new set of results of TEC disturbance patterns during 180 geomagnetic storms to describe seasonal and solar cycle effects. It concludes with a set of open questions that require additional study.

Ionospheric electron content within the equatorial F 2 layer anomaly belt

Abstract: Results are presented on continuous TEC measurements, taken along a chain of stations spaced between 0 deg N and 25 deg N and aligned roughly along the same longitude sector in India, that describe the day-to-day behavior of the location of equatorial anomaly in the TEC during the period of the 1975-1976 sunspot minimum, when the ATS spacecraft was visible from India. It was found that the presence or absence of the latitudinal anomaly in TEC on a particular day depended only on the strength of the electrojet current, as determined by the difference of the horizontal magnetic field at stations on the magnetic equator and stations outside the equatorial electrojet, rather than on the horizontal magnetic field measured only at equatorial stations.

Recent progress in satellite radio beacon studies with particular emphasis on the ATS-6 radio beacon experiment

Abstract: In May 1974 a new era in satellite radio beacon studies of the ionosphere opened with the ATS-6 Radio Beacon Experiment. The history of radio beacon studies up to that time is reviewed briefly and the particular features of the ATS-6 beacon are discussed together with the basic theory required to interpret the measurements. The main emphasis is on the ATS-6 beacon experiment but other beacon data are discussed which provide the necessary background. The diurnal and seasonal variations of the total electron content and the plasmaspheric content are presented for the U.S.A. and Europe. In winter the plasmaspheric content over the Western Hemisphere maximizes at night while in Europe and the Pacific it appears to peak near noon. This is thought to be caused by flow of plasma from the local and conjugate ionospheres. Night maxima of total electron content are found showing that they do not arise from depletions of the plasmaspheric content. The plasmaspheric content is highly sensitive to solarterrestrial disturbance, it reaches a minimum on the third day of a storm and may take between 10 and 20 days of partial filling and emptying to recover. Traveling disturbances in U.S.A., Europe, and India show similarities of speeds but not of direction. Beacon observations of micropulsations in total content, tropospheric fluctuations and Fresnel diffraction by intense ionospheric irregularities are discussed together with radio wave scintillations and some applications of beacon radio data to communications and navigation.

Estimating the daytime Equatorial Ionization Anomaly strength from electric field proxies

Abstract: [1] The Equatorial Ionization Anomaly (EIA) is a significant feature of the low-latitude ionosphere. During daytime, the eastward electric field drives a vertical plasma fountain at the magnetic equator creating the EIA. Since the eastward electric field is also the driving force for the Equatorial Electrojet (EEJ), the latter is positively correlated with the EIA strength. We investigate the correlation between the zonal electric field and the EIA in the Peruvian sector and compare the results with correlations of the EEJ versus EIA strength. Analyzing 5 years of Challenging Minisatellite Payload (CHAMP) electron density measurements, plasma drift readings from the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere (JULIA) radar, and magnetic field observations at Huancayo and Piura, we find the EEJ strength and the zonal electric field to be suitable proxies for the EIA intensity. Both analyses reveal high correlation coefficients of cc > 0.8. A typical response time of the EIA to variations in the zonal electric field is ∼1–2 h, and it is ∼2–4 h after EEJ strength variations. Quantitative expressions are provided, which directly relate the EIA parameters to both proxies. From these relations, we infer that an EIA develops also during weak Counter Electrojets (CEJs), but no EIA forms when the vertical plasma drift is zero. For positive EEJ magnetic signatures to form, a minimum eastward electric field of 0.2 mV/m is required on average. The above-mentioned delay between EIA and EEJ variations of ∼3 h is further confirmed by the investigation of the EIA response to transitions from CEJ to EEJ, e.g., during late morning hours.