oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 13 )

2019 ( 550 )

2018 ( 641 )

2017 ( 651 )

Custom range...

Search Results: 1 - 10 of 388455 matches for " I. S. Dubitskiy "
All listed articles are free for downloading (OA Articles)
Page 1 /388455
Display every page Item
Spin-ice behavior of three-dimensional inverse opal-like magnetic structures: micromagnetic simulations
I. S. Dubitskiy,A. V. Syromyatnikov,N. A. Grigoryeva,A. A. Mistonov,S. V. Grigoriev
Physics , 2015,
Abstract: We perform micromagnetic simulations of the magnetization distribution in the inverse opal-like structures (IOLS) made from the ferromagnetic materials (nickel and cobalt). It is shown that the unit cell of these complex structures, which characteristic length is approximately 700 nm, can be divided into a set of structural elements some of which behave like the Ising-like objects. A spin-ice behavior of IOLS is observed in a broad range of external magnetic fields signifying an effective frustrating interaction between the Ising-like structural units. Numerical results describe successfully the experimental hysteresis curve of the magnetization of the Ni and Co based IOLS. We conclude that magnetic IOLS can be considered as the first realization of three-dimensional artificial spin ice.
Review of the Book “Magnetooptical Spectroscopy of the Rare-Earth Compounds: Development and Application”  [PDF]
I. S. Edelman
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.45030
Abstract: This book reviews and provides numerous theoretical calculations for the first time relevant to the optics and magneto-optics of the trivalent rare earth ions (RE3+) and their compounds. The RE3+ have unique spectroscopic properties that make them exceptionally attractive to both scientists, who probe the fundamental properties of these systems, and engineers, who develop these systems into photonic devices eagerly marketed in expanded technologies. Magneto-optical effects in compounds doped with RE3+ have been studied since the dawn of modern physics and have had a profound impact on their development in terms of practical opto-electronic devices. The authors of this new, exciting, and fresh text are world famous in this field, with over 150 years of experience in developing important theoretical and experimental contributions and over fifty years of more than 500 refereed publications in this field in the Soviet Union and the United States. They offer both a conceptual description of magneto-optical phenomena, as well as clear, detailed theoretical development published for the first time of many of the phenomena only briefly addressed in the literature. The book is based on the author’s original work in theoretical and experimental investigations in magneto-optics. Numerous graphs and simple examples model the phenomena described in the text, making it a highly desirable treatise for scientists beginning their studies in the field of magneto-optics.
Is Gravitational Radiation a Radiation of the Same Level as Electromagnetic Radiation?  [PDF]
Stanislav I. Fisenko, I. S. Fisenko
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.515140
Abstract: The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on the theoretically proven and experimentally confirmed facts of the existence of stationary states of an electron in its gravitational field, characterized by the gravitational constant K = 1042 G (G is Newtonian gravitational constant) and unrecoverable space-time curvature Λ. These experimental facts include, in particular, data on the broadening of the spectra of the characteristic radiation of multielectron atoms. This broadening of the spectra can be only due to the additional broadening mechanism, in particular the presence of excited states of electrons in their gravitational field. Another fact is the new line in the X-ray emission spectrum according to the results of observation with MOS-camera of the XMM-Newton observatory. This line unlike other identified lines of electromagnetic radiation cannot be assigned to any atomic transition.
Thermonuclear Plasma Steady States Generation  [PDF]
S. I. Fisenko, I. S. Fisenko, R. T. Rymkulov
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.25001
Abstract: This report is a systematic and complemented summary of the earlier published works by the authors [1-4]. The concept of gravitational radiation as a radiation of one level with the electromagnetic radiation is based on theoretically proved and experimentally confirmed fact of existence of electron’s stationary states in own gravitational field, characterized by gravitational constant K = 1042 G (G—Newtonian gravitational constant) and by irremovable space-time curvature. The received results strictly correspond to principles of the relativistic theory of gravitation and the quantum mechanics. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational radiation spectrum such that amplification of gravitational radiation may take place only in multiple-charge ion high-temperature plasma.
The biological potency of benzapyrene in the humates composition  [PDF]
L. I. Belykh, I. A. Ryabchikova, S. S. Timofeyeva
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.412085
Abstract:

The aim of the paper was to determine benz(a)-pyrene in the preparations containing humates and study the benz(a)pyrene biological potency for the agricultural plants. The research methodology included the determination of the dependencies in the system “substance concentration (dose)effect on the plant”. Concentrations of benz(a)pyrene in 12 samples of the humates preparations and fertilizers based on their trademarks “Irkutsk humates”, obtained from brown coal, varied in the range from 0.3 to 50 mcg/kg, which creates no soil contamination in conditions of the use of preparations. Between contents of benz(a)pyrene and humates there is a correlation (rxy = 0.95; α = 0.05). It is ascertained that the effects of stimulation and/or inhibition of the growth and yield of agricultural plants depend on the concentration of benz(a)pyrene and the method of plant processing. Optimal concentrations of benz(a)pyrene were 150-200 ng/dm3 for preplant way of processing of potato tubers, 3-10 ng/dm3for top dressing (spraying) and 0.1-0.3 ng/dm3for dressing under the roots (hydroponic). The obtained results allowed us to offer one of the possible mechanisms of biological potency of humates as the plant growth stimulants, and also a way testing of the preparations by screening of their benz(a)pyrene content.

Delta Modulation with PI Controller—A Comparative Study  [PDF]
A. I. MASWOOD, S. ANJUM
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2009, DOI: 10.4236/jemaa.2009.13023
Abstract: The paper discusses the application of PWM delta modulation with PI controller as an alternative to the standard PWM techniques for providing gating signals to the voltage source inverters. Its inherent characteristics of constant volts/Hertz control without feedback complexity and boosting of the fundamental voltage makes it an excellent choice for motor drive applications. This paper discusses the comparison between a basic delta modulation, the advanced Delta modulation with PI controller and an optimized DMPI. It is shown that in addition to the aforementioned advantages, VSI with optimized DMPI produces superior load current/voltage waveforms compared to simple DMPI, when IGBT is employed as a switching device for the inverter. Since the tacho feedback or other traditional speed sensing means is not permissible in sealed motor or the pump, a novel method is used to monitor the motor speed from the terminal quantities like voltage, current, and motor input power factor.
Model for Predictive Analysis of the Concentration of Phosphorus Removed during Leaching of Iron Oxide Ore in Sulphuric Acid Solution  [PDF]
C. I. Nwoye, S. Ndlu
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.84023
Abstract: Model for predictive analysis of the concentration of phosphorus removed (relative to the initial and final pH of the leaching solution) during leaching of iron oxide ore in sulphuric acid solution has been derived. It was observed that the validity of the model is rooted in the mathematical expression; (P/N)1/3 = (er/a) where both sides of the relationship are almost equal. The model; P = 4.25(er/a)3 shows that the concentration of phosphorus removed is dependent on the values of the initial and final pH of the leaching solution. In all, the positive or negative deviation of the model-predicted phosphorus concentration from its corresponding value obtained from the experiment was found to be less than 29%, which is quite within the acceptable deviation limit of experimental results hence establishing the validity and precision of the model in its application for predicting quantitatively the concentration of phosphorus removed during the leaching process.
Oxidation Behaviour of a Newly Developed Superalloy  [PDF]
I.V.S. Yashwanth, I. Gurrappa, H. Murakami
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2011, DOI: 10.4236/jsemat.2011.13020
Abstract: The current paper explains the oxidation behaviour of a newly developed nickel-based superalloy in simulating aero gas turbine engine conditions. The results showed that the new superalloy is highly susceptible to high temperature oxidation. Within three of hours of oxidation, extensive oxide scales were formed. The formed oxide scales were ana-lysed with electron dispersive spectroscopy (EDS) and morphology was studied with scanning electron microscope (SEM) for varied oxidation times. The oxidation products were determined with XRD and cross sections of all the oxi-dised superalloys were also studied. The elemental distribution of all the superalloys after oxidation was also studied with a view to understand and compare the characteristics of the new superalloy with other superalloys. Finally, an oxidation mechanism that is responsible for its faster degradation under elevated temperatures was established based on the results obtained with different techniques and presented in detail.
The Behaviour of Superalloys in Marine Gas Turbine Engine Conditions  [PDF]
I. Gurrappa, A. K. Gogia, I. V. S. Yashwanth
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2011, DOI: 10.4236/jsemat.2011.13022
Abstract: This paper presents hot corrosion results carried out systematically on the selected nickel based superalloys such as IN 738 LC, GTM-SU-718 and GTM-SU-263 for marine gas turbine engines both at high and low temperatures that represent type I and type II hot corrosion respectively. The results were compared with advanced superalloy under similar conditions in order to understand the characteristics of the selected superalloys. It is observed that the selected superalloys are relatively more resistant to type I and type II hot corrosion when compared to advanced superalloy. In fact, the advanced superalloy is extremely vulnerable to both types of hot corrosion. Subsequently, the relevant reaction mechanisms that are responsible for slow and faster degradation of various superalloys under varied hot corrosion conditions were discussed. Based on the results obtained with different techniques, a degradation mechanism for all the selected superalloys as well as advanced superalloy under both types of hot corrosion conditions was explained. Finally, the necessity as well as developmental efforts with regard to smart corrosion resistant coatings for their effective protection under high temperature conditions was stressed for their enhanced efficiency.
Vacuum Delivery in a Tertiary Institution, in Northern Nigeria: A 5-Year Review  [PDF]
I. A. Yakasai, I. S. Abubakar, E. M. Yunus
Open Journal of Obstetrics and Gynecology (OJOG) , 2015, DOI: 10.4236/ojog.2015.54031
Abstract:

Background: There is a progressive shift away from the use of forceps in favour of the vacuum extractor as the instrument of choice for operative vaginal deliveries. The overall objective of this is to improve safe motherhood by reducing the contribution of second stage of labour complications to maternal mortality and morbidity. Objective: This study was carried out to determine the incidence, indications, outcome and complications of Ventouse delivery in Aminu Kano Teaching Hospital, Kano, Nigeria. Materials and Methods: This was a retrospective study carried out at the Aminu Kano Teaching Hospital. The case notes of all parturients who had vacuum deliveries in the hospital within January 2008 to December 2012 were retrieved from the statistics unit of the hospital and analysed using SPSS. Results: 22,680 patients delivered in the hospital over this 5-year period. Ventouse was used on 210 occasions giving an incidence rate of 0.9%. One hundred and eighty (85.7%) had successful vacuum delivery. The failed extractions (14.3%) were delivered by caesarean sections. The mean age of the patients was 29.4 years. The mean parity was 2.2. Ninety (42.9%) were primipara while 120 (57.1%) were multipara. The commonest indication for the vacuum delivery was prolonged second stage of labour in 45.2% of cases. The commonest maternal complication was primary postpartum haemorrhage (9.5%). Foetal complication occurred in about 31% of vacuum deliveries, the commonest (18.1%), being cephalhaematoma. Conclusion: The incidence rate of vacuum delivery is low. Thus, active training in the art of vacuum assisted vaginal delivery is clearly needed during residency.

Page 1 /388455
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.