In this paper, the effects of two-temperature electrons on the slow and fast modulation instability and envelope solitons of ion-acoustic waves have been theoretically studied in a fully relativistic plasma using the method of Fried and Ichikawa. The expression of the nonlinear Schrodinger equation in fully relativistic plasma has been derived and the condition for the existence of slow and fast modulation instability of ion-acoustic wave is obtained. From the nonlinear Schrodinger equation, the solutions for slow and fast envelope solitons in the fully relativistic plasma are also obtained. The profiles of the growth rate of modulation instability and envelope solitons are drawn and discussed taking different values of ion-stream velocity and density and temperature of two-temperature electrons. The results are applicable to the study of ion-acoustic envelope solitons both in weak- and ultra- relativistic plasma.

Considering a weakly relativistic plasma having non-isothermal single temperature electrons, the ion-acoustic solitons up to third order have been theoretically studied using the tanh method (hyperbolic tangent method). It is found that the first-order ion-acoustic solitons have Sech4-type profile and second-order ion-acoustic solitons have Sech2-type profiles, but the third-order ion-acoustic solitons are Sech4-type profile giving the spiky solitons and Cosech4-type profile giving the explosive solitons in the weakly relativistic plasma. The profiles of the solitons are drawn and discussed considering different values of relativistic ion stream velocity and non-isothermal electrons.

Using the integral form of governing equation in terms of pseudopotential, the effect of higher-order nonlinear and dispersive effects on the dressed solitons (DS) and double layers (DL) of ion-acoustic waves has been theoretically studied in an ultra-relativistic degenerate (URD) plasma consisting of cold inertial ions, degenerate two-temperature electrons and negatively charged dust particles. The solution of DS in such plasma is obtained up to second-order approximation. The profiles of DS are drawn and discussed for different values of density and temperature of this plasma. The DS is compressive in the plasma for different values of density and temperature of degenerate electrons, and its amplitude is much larger than that of the first-order (KdV) solitons. The DS is compressive with wave-like structure for some value of the temperature of degenerate electrons, and its amplitude is lower than that of the KdV solitons. Moreover, the solution for the DS near-critical state is obtained and discussed graphically. Near-critical state, the temperatures of URD electrons have important roles in the DS. The solution of DL in the plasma has also been obtained and graphically discussed. Both compressive and rarefactive DL will be excited in URD two-temperature-electron plasma for different values of the electron density. But, only rarefactive DL would be excited in this plasma for different values of the electron temperature. The results are new and these would be applicable in space plasma.

Slow and fast modulation instability and envelope soliton of ion-acoustic wave (IAW) are studied in an electron–ion–positron plasma when the ions are warm and have constant stream velocity, positrons are isothermal and electrons are superthermal. The non-linear Schrodinger (NLS) equation has been derived using the Fried and Ichikawa method and the solution of envelope soliton is obtained. It is seen that IAW propagates with two modes (slow and fast) in the presence of an ion stream in the plasma which results in slow and fast modulation instability of the wave. The stability criteria for slow mode (SM) and fast mode (FM) of the wave are established and studied graphically for different values of the ion temperature, positron density, positron temperature and kappa factor of electrons. The bright envelope soliton and dark envelope soliton of SM and FMs of the wave in electron–ion–positron plasma are also studied. The solution of rogue waves (RWs) is obtained from the NLS equation and the nature of RWs of the SM and FM of the wave is discussed graphically. Our results are new and no author has reported this kind of results of slow and fast modulation instability of IAW till now.

Ion acoustic double layers in a multicomponent plasma consisting of positive ions, negative ions, and nonthermal electrons filled in a cylindrical waveguide have been theoretically investigated using pseudopotential technique. The expression of Sagdeev potential for the ion acoustic wave in such a plasma has been derived, and the conditions for the existence of double layers are obtained. The effects of the boundary of cylindrical waveguide and nonthermal electrons on the Sagdeev potential have been graphically discussed. From the nonlinear equation, the solution for double layers of small amplitude ion acoustic waves is obtained, and the structure of double layers is analyzed as function of the plasma parameters. It is seen that finite geometry of bounded plasma, nonthermality of electrons, density of negative ions, and stream velocity of positive and negative ions have significant contribution on the structure of double layers. The double layers may be compressive or rarefactive in plasma depending upon the values of the plasma parameters.

Background: Diabetic ulcers are the most common foot injuries leading to lower extremity amputation. The present study was done to identify the incidence and related risk factors of diabetic foot ulcers in study participants.Methods: This was a prospective done on 50 patients with diabetic foot ulcers. All the patients were examined thoroughly and related laboratory investigations were done. Wound culture and sensitivity was done in all cases.Results: Mean age of onset with foot ulcers was 53.5 yrs in male and 55 yrs in females. Nephropathy was present in 12 (24%) patients. Sensorimotor neuropathy was present in 29 (58%) cases and autonomic neuropathy was present in 06 (12%) cases. Most common infection identified in diabetic foot ulcers was due to gram-negative bacteria (E. coli in 45 cases). Major amputation was done in 2 (4%) patients.Conclusions: Implementation of management strategies at early stages prevents the development of complications related to diabetic foot ulcers in patients.

Modulation instability, bright envelope soliton, and rogue waves of ion acoustic waves in dense plasma consisting of ultra-relativistic degenerate electrons and positrons, cold and mobile inertial ions, and negatively charged static dust particles have been investigated using Fried and Ichikawa method. Nonlinear Schrödinger equation has been derived and the growth rate of modulationally unstable ion acoustic wave in such plasma are discussed. It has been found that ion acoustic wave will be always modulationally unstable for all possible values of density of positrons, electrons, and charged dust particle. The solutions of envelope solitons and rogue waves are obtained from the nonlinear Schrödinger equation. The theoretical results have been analyzed numerically and graphically for different values of plasma parameters. It is found that only bright envelope soliton would be excited in the ultra-relativistic degenerate plasma. Our results are new and may be applicable for the study of nonlinear wave processes in relativistic degenerate dense plasmas of astrophysical objects, namely, in white dwarfs and neutron stars.

Nonlinear propagation of ion acoustic waves has been studied in unmagnetized quantum (degenerate) plasma in the presence of an ion beam using the one-dimensional quantum hydrodynamic model. The Korteweg–de Vries (K–dV) equation has been derived by using the reductive perturbation technique. The solution of ion acoustic solitary waves is obtained from the K–dV equation. The theoretical results have been analyzed numerically for different values of plasma parameters and the results are presented graphically. It is seen that the formation and structure of solitary waves are significantly affected by the ion beam in quantum plasma. The solitary waves will be compressive or rarefactive depending upon the values of velocity, concentration, and temperature of the ion beam. The critical value of ion beam density for the nonexistence of solitary wave has been numerically estimated, and its variation with velocity and temperature of ion beam has been discussed graphically. The results are new and would be very useful for understanding the beam–plasma interactions and the formation of nonlinear wave structures in dense quantum plasma.

Purpose : Shrikhand Spread, a unique sweetened fermented Indian milk product is made by separation of whey from dahi , the Indian counterpart of Western yoghurt, followed by addition of sugar. Production of dahi employing traditional method involved undefined mixed starter cultures, uncontrolled fermentation and longer production time resulting in wide variation in its chemical and microbiological qualities. In order to cater to a product with desirable properties like lower post-acidification, higher flavour profile, firm body and lower syneresis coupled with shorter production time, conjugated application of yoghurt cultures and dahi cultures were tried. Since the shelf-life of dahi is limited, conversion into shrikhand spread may be used as a tool to extend the shelf-life and therefore the market reach towards commercialization into the global market as a potential functional food. Design/Methodology/Approach : Different batches of dahi were made from homogenized (Stage I - 2500 psi, Stage II - 500 psi) and pasteurized (74-78 °C/16-19 Sec) milk, pre-adjusted to 3.15-3.20% fat and 11.40% snf with diverse starter combinations selected upon the extent of post acidification, volatile acid production, syneresis and rheological characteristics. Homogenized, pasteurized and regulated milk was further subjected to a heat-treatment (90°C/10 min) and seeded with selected starter combinations to obtain firm curd intended for shrikhand spread manufacture. Shelf-life of shrikhand spread was evaluated in terms of chemical and microbiological criteria upto 7 days of storage at 8±1°C. Findings : Starter combination of eXactDahi 2+YoFlex Express 1.0 at an incubation temperature-time combination of 45°C/5h was found most suitable for producing dahi with smooth body, higher volatile acidity and low syneresis. Utilization of dahi obtained employing the above starter combination for the manufacture shrikhand spread was suggested and the product was found to retain its goodness when stored for 7 days at 8±1°C. Originality/Value : Conjugated use of yoghurt cultures with dahi cultures was suggested to overcome the drawbacks of traditional process of dahi manufacture suitable for conversion into shrikhand spread. This dahi was found capable of enhancing its dietetic value in addition.

Nonlinear propagation of ion-acoustic waves in self-gravitating multicomponent dusty plasma consisting of positive ions, non-isothermal two-temperature electrons and negatively charged dust particles with fluctuating charges and drifting ions has been studied using the reductive perturbation method. It has been shown that nonlinear propagation of ion-acoustic waves in gravitating dusty plasma is described by an uncoupled third order partial differential equation which is a modified form of Korteweg–deVries equation, in contraries to the coupled nonlinear equations obtained by earlier authors. Quasi-soliton solution for the ion-acoustic solitary wave has been obtained from this uncoupled nonlinear equation. Effects of non-isothermal two-temperature electrons, gravity, dust charge fluctuation and drift motion of ions on the ion-acoustic solitary waves have been discussed.

Modulational instability of ion-acoustic wave in an electron-ion-positron plasma is analyzed when the electrons are kappa distributed. Instead of the age old method of reductive perturbation technique we have followed a different methodology put forward by Zakharov, Karpman, Fried and Ichikawa. In this approach the stress is more on physics than the formalism. The nonlinear Schrodinger equation is derived and its two kinds of solution are obtained- Envelope Soliton and Rational Soliton. The stability criteria are established and studied by varying the positron density, temperature and wave number. Over and above we have found both dark- soliton and bright- soliton. An important feature of this method is that we can proceed to the critical case in a much simpler way. It may be added that the rational soliton is not a rogon, but a different form of nonlinear excitation for those values of plasma parameters for which we could test stability.

Sagdeev potential approach is used for the study of nonlinear propagation of ion-acoustic waves in plasma consisting of cold positive ions and nonthermal electrons. The nonlinear equation so derived are analysed with the help of Bogoliubov–Mitropolosky method. The profiles of Sagdeev potential solitary waves are evaluated in first-, second- and third- order which are depicted for different values of nonthermal parameter of electrons. It is seen that nonthermal electrons has considerable impact on the shape of ion-acoustic solitary waves in each order. The plasma consisting of cold positive ions and no negative ions can support the formation of compressive as well as W-type solitary waves in second- and third- order for certain value of nonthermal parameter of electrons. The results are new because W-type ion-acoustic solitary wave is found by earlier authors in plasma in presence of negative ions only. The ion-acoustic solitary waves near critical value of nonthermal parameter and arbitrary amplitude solitary waves in presence of nonthermal electrons have also been studied in the paper. Moreover, the solution for ion-acoustic double layers in plasma consisting of nonthermal electrons is obtained. Our results in the paper would be useful to understand the nonlinear wave processes in ionospheric and magnetospheric multicomponent plasma having nonthermal electrons.

Abstract—Using quantum hydrodynamical (QHD) model the linear dispersion relation for the electron plasma waves propagating in a cylindrical waveguide filled with a dense plasma containing streaming electron, hole and stationary charged dust particles has been derived. It is shown that the effect of finite boundary and stream velocity of electrons and holes make some of the possible modes of propagation linearly unstable. The growth rate of this instability is shown to depend significantly on different plasma parameters.

Using the Sagdeev's pseudopotential approach, effects of non-thermal electrons and warm negative ions on the conditions for existence and structure of first and second order ion-acoustic solitary waves have been investigated in a multicomponent drifting plasma. It is shown that there exists a critical concentration of negative ions which decides the existence and nature of the ion-acoustic solitary waves. It is found that the non-thermal electrons, the concentration of negative ions and the temperature of negative ions have significant contributions towards the excitation and structure of the ion-acoustic solitary waves. The plasma under consideration can support the formation of compressive, rarefactive as well as W-type solitons with certain restricted values of plasma parameters. The results are important in the context of ionospheric and magnetospheric plasmas.

The pseudopotential technique is applied to a multicomponent plasma consisting of nonthermal electrons and warm positive and negative ions with drift motion with a view to studying ion-acoustic double layers. Conditions for the existence of such layers are obtained, two critical concentrations of negative ions being identified which control the formation and nature of the ion-acoustic double layers. The effects of nonthermal electrons, negative-ion concentration, and negative-ion temperature on the double layer formation and structure are also investigated. The nonthermal electrons and the negative ions are shown to contribute significantly to the excitation and structure of the double layers. The importance of the results in the context of magnetospheric and auroral plasmas is discussed.

Using one dimensional Quantum hydrodynamic (QHD) model Korteweg de Vries (KdV) solitary excitations of electron-acoustic waves (EAWs) have been examined in twoelectron-populated relativistically degenerate super dense plasma. It is found that relativistic degeneracy parameter influences the conditions of formation and properties of solitary structures. Keywords—Relativistic Degeneracy, Electron-Acoustic Waves, Quantum Plasma, KdV Equation.

Theory of the generation of magnetic moment field from resonant interaction of three high frequency electromagnetic waves in un-magnetized dense electron plasma is developed including the relativistic change of electron mass. It is shown that the inclusion of relativistic effect enhances the magnetic moment field. For high intensity laser beams this moment field may be of the order of a few mega gauss. Such a high magnetic field can considerably affect the transport of electrons in fusion plasma.

Using the Quantum hydrodynamic (QHD) model Korteweg-de Vries (KdV) type solitary excitations of electron-acoustic waves (EAWs) have been examined in a two-electron-populated relativistically degenerate super dense plasma. It is shown that relativistic degeneracy parameter significantly influences the conditions of formation and properties of solitary structures.

Modulational instability of high frequency surface waves on a plasma half-space is investigated taking into account finite temperature effects. The second harmonic generated through nonlinear self-interaction of the waves is found to carry a fraction of the surface wave energy into the bulk of the plasma. This is found to influence the modulational instability mechanism. To describe the nonlinear evolution of the wave, a nonlinear Schrodinger equation is derived in which the coefficient of the nonlinear term becomes a complex quantity. From this evolution equation we derive the condition of instability and show that high-frequency surface waves on a warm plasma half-space are modulationally unstable.

Using one-dimensional quantum hydrodynamic model, the linear and non-linear characteristics of electron plasma waves have been studied both analytically and numerically in a I two-component unmagnetized dense quantum plasma with streaming motion. It is shown that quantum effect modifies the linear dispersion character of the electron plasma waves and streaming effect makes it possible the excitation of two distinct modes. To describe the non-linear behaviour, Korteweg de Vries equation is derived by using the standard reductive perturbation technique and incorporating quantum-mechanical effects. It is shown that depending on/some critical values of the quantum diffraction parameter both rarefactive and compressive type of solitons can exist in the model plasma. The structure of the solitary waves is shown to be significantly affected by the quantum plasma parameters and streaming motion.