Propagation of plane waves in an orthotropic magneto-thermodiffusive rotating half-space

Suresh Kumar Sheokand,Rajesh Kumar,Kapil Kumar Kalkal,Sunita Deswal 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.4

The present article is aimed at studying the reflection phenomena of plane waves in a homogeneous, orthotropic, initially stressed magneto-thermoelastic rotating medium with diffusion. The enuciation is applied to generalized thermoelasticity based on Lord-Shulman theory. There exist four coupled waves, namely, quasi-longitudinal P-wave (qP), quasi-longitudinal thermal wave (qT), quasi-longitudinal mass diffusive wave (qMD) and quasi-transverse wave (qSV) in the medium. The amplitude and energy ratios for these reflected waves are derived and the numerical computations have been carried out with the help of MATLAB programming. The effects of rotation, initial stress, magnetic and diffusion parameters on the amplitude ratios are depicted graphically. The expressions of energy ratios have also been obtained in explicit form and are shown graphically as functions of angle of incidence. It has been verified that during reflection phenomena, the sum of energy ratios is equal to unity at each angle of incidence. Effect of anisotropy is also depicted on velocities of various reflected waves.

Modal parametric changes in a steel bridge with retrofitting

Suresh Kumar Walia,Hemant Kumar Vinayak,Ashok Kumar,Raman Parti 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.2

This paper presents the status improvement of an old damaged deck type rural road steel truss bridge through the modal parametric study after partial retrofitting. The dynamic and static tests on bridge were carried out as in damaged state and after partial retrofitting. The dynamic testing on the steel bridge was carried out using accelerometers under similar environmental conditions with same speed of the moving vehicle. The comparison of the modal parameters i.e., frequency, mode shape mode shape curvature, modal strain energy, along with the deflection parameter are studied with respect to structural analytical model parameters. The status up gradation for the upper and downstream truss obtained was different due to differential level of damage in the bridge. Also after retrofitting the structural elemental behavior obtained was not same as desired. The damage level obtained through static tests carried out using total station indicated further retrofitting requirement.

Random number sensitivity in simulation of wind loads

Kumar, K. Suresh Techno-Press 2000 Wind and Structures, An International Journal (WAS Vol.3 No.1

Recently, an efficient and practical method has been developed for the generation of univariate non-Gaussian wind pressure time histories on low building roofs; this methodology requires intermittent exponential random numbers for the simulation. On the other hand, the conventional spectral representation scheme with random phase is found suitable for the generation of univariate Gaussian wind pressure time histories on low building roofs; this simulation scheme requires uniform random numbers. The dependency of these simulation methodologies on the random number generator is one of the items affecting the accuracy of the simultion result; therefore, an attempt has been made to investigate the issue. This note presents the observed sensitivity of random number sets in repetitive simulations of Gaussian and non-Gaussian wind pressures.

International Collaboration for High-Efficiency III-V//Si Tandem Solar Cells

Suresh Kumar Dhungel,Somin Park,Seungyong Han,Duy Phong Pham,Youngkuk Kim,Junsin Yi 한국신재생에너지학회 2022 AFORE Vol.2022 No.9

GIS/GPS based Precision Agriculture Model in India –A Case study

Suresh Kumar Mudda 한국농식품정보과학회 2018 Agribusiness and Information Management Vol.10 No.2

In the present day context of changing information needs of the farmers and diversified production systems there is an urgent need to look for the effective extension support system for the small and marginal farmers in the developing countries like India. The rapid developments in the collection and analysis of field data by using the spatial technologies like GPS&GIS were made available for the extension functionaries and clientele for the diversified information needs. This article describes the GIS and GPS based decision support system in precision agriculture for the resource poor farmers. Precision farming techniques are employed to increase yield, reduce production costs, and minimize negative impacts to the environment. The parameters those can affect the crop yields, anomalous factors and variations in management practices can be evaluated through this GPS and GIS based applications. The spatial visualisation capabilities of GIS technology interfaced with a relational database provide an effective method for analysing and displaying the impacts of Extension education and outreach projects for small and marginal farmers in precision agriculture. This approach mainly benefits from the emergence and convergence of several technologies, including the Global Positioning System (GPS), geographic information system (GIS), miniaturised computer components, automatic control, in-field and remote sensing, mobile computing, advanced information processing, and telecommunications. The PPP convergence of person (farmer), project (the operational field) and pixel (the digital images related to the field and the crop grown in the field) will better be addressed by this decision support model. So the convergence and emergence of such information will further pave the way for categorisation and grouping of the production systems for the better extension delivery. In a big country like India where the farmers and holdings are many in number and diversified categorically such grouping is inevitable and also economical. With this premise an attempt has been made to develop a precision farming model suitable for the developing countries like India.

Performance study of various discontinuous PWM strategies for multilevel inverters using generalized space vector algorithm

Suresh Kumar, A.,Sri Gowri, K.,Vijaya Kumar, M. The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.1

The space vector (SV) pulse-width modulation (PWM) approach is extensively preferred in the control of multilevel inverters (MLI). In this paper, the implementation of various advanced discontinuous pulse-width modulation (ADPWM) strategies using a generalized space vector algorithm is presented. The ADPWM MIN, ADPWM MAX, and ADPWM 0~ADPWM 3, strategies are developed using a combination of advanced switching sequences 1012-2721 and 0121-7212. The output performance in terms of voltage THD, current THD, and reduction of common mode voltage (CMV) of a three-level inverter-fed induction motor for different ADPWM strategies is investigated initially through MATLAB simulation and comparison of the obtained results is presented. It can be observed that the ADPWM 1 strategy with the 0121-7212 switching sequence offered the best performance in terms of the voltage and current THD at the modulation range of 47.5 Hz to 50 Hz. In addition, it is validated experimentally. Experimental work is done on a V/f-controlled three-level inverter-fed induction motor with the help of dSPACE. To validate the study, experimental results of the line voltage, stator current, and CMV waveforms for the ADPWM 1 (optimal performance PWM strategy) are presented in comparison with the 0127 sequence at fundamental frequencies of 49 Hz and 30 Hz.

Spectral density functions of wind pressures on various low building roof geometries

Kumar, K. Suresh,Stathopoulos, T. Techno-Press 1998 Wind and Structures, An International Journal (WAS Vol.1 No.3

This paper describes in detail the features of an extensive study on Spectral Density Functions (SDF's) of wind pressures acting on several low building roof geometries carried out in a boundary layer wind tunnel. Various spectral characteristics of wind pressures on roofs with emphasis on derivation of suitable analytical representation of spectra and determination of characteristic spectral shapes are shown. Standard spectral shapes associated with various zones of each roof and their parameters are provided. The established spectral parameters can be used to generate synthetic spectra adequate for the simulation of wind pressure fluctuations on building surfaces in a generic fashion.

Electrospray ionization tandem mass spectrometry for rapid, sensitive and direct detection of melamine in dairy products

Suresh Kumar Kailasa,Hui-Fen Wu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

A simple, rapid, and sensitive method for detection of melamine in dairy products by electrosprayionization mass spectrometry (ESI–MS) without any sample preparation is demonstrated. The ESI–MS/MS on the protonated melamine atm/z 127 produced the characteristic fragment ions atm/z 110, 85, 68,60. This method has a good linearity in the range of 0.5–10.0 mg/mL, with detection limit 0.1 mg/mL andRSD 8.9% (n = 5). Together with existing recent methods on mass spectrometry and NP-based sensingmethodologies for melamine detection, the present method provides an efficient platform for detectionof melamine in milk products without any sample preparation steps or post-separation procedures.

Prediction of pressure equalization performance of rainscreen walls

Kumar, K. Suresh,van Schijndel, A.W.M. Techno-Press 1999 Wind and Structures, An International Journal (WAS Vol.2 No.4

In recent years, rainscreen walls based on the pressure equalization principle are often used in building construction. To improve the understanding of the influence of several design parameters on the pressure equalization performance of such wall systems, a theoretical consideration of the problem may be more appropriate. On this basis, this paper presents two theoretical models, one based on mass balance and the other based on the Helmholtz resonator theory, for the prediction of cavity pressure in rigid rainscreen walls. New measures to assess the degree of pressure equalization of rainscreen walls are also suggested. The results show that the model based on mass balance is sufficiently accurate and efficient in predicting the cavity pressure variations. Further, the performance of the proposed model is evaluated utilizing the data obtained from full-scale tests and the results are discussed in detail.

Experimental strategy for acid-free plutonium recovery from assorted matrices: Non-aqueous leaching followed by selective solid phase extraction

Kumar Shiny Suresh,Rao Ankita,Srivastava Ashutosh,Yadav Kartikey Kumar,Lenka Raja Kishore 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11

Methodologies comprising usage of innocuous reagents, lower overall chemical inventory and simplification of process scheme for plutonium recovery from assorted matrices, solid as well as liquid, are key to establishing sustainability of the nuclear fuel cycle. The present study demonstrates, for the first-time, plutonium leaching from different refractory matrices: oxide, mixed oxide as well as simulated cellulosic waste using the benign halide anion free choline citrate - urea (1 : 2 mole ratio) based eutectic solvent (referred to as CU). This mineral acid and hydrofluoric acid-free, non-aqueous route of plutonium recovery with controlled infra-red heating yielded ≥93% efficiency. CU was diluted with biodegradable, less viscous propylene glycol (referred to as PG), which was chosen as the non-aqueous polar phase for facile solid phase extraction (SPE), which is a green alternative to liquid-liquid extraction owing to process simplification and solvent inventory reduction. Exclusive stabilization of tetravalent plutonium in the novel media, confirmed by ultraviolet-visible spectrophotometry and electrochemical methods, led to process simplification, eliminating any pre-extraction requirement for oxidation state adjustment. Extractant, di-2-ethyl hexyl phosphoric acid encapsulated polyether sulfone beads, prepared by phase inversion method, were employed for efficient SPE of plutonium (Distribution co-efficient, kD=950±6). Selectivity of non-aqueous SPE was found to be Pu(IV)≫UO 2+ 2 >Am(III) vis-à-vis aqueous acid medium.