Synthesis of nitrogen doped coiled double walled carbon nanotubes by chemical vapor deposition method for supercapacitor applications

V. Thirumal,A. Pandurangan,Mohd Mahadi Halim,S.R. Krishnamoorthi,R. Ilangovan 한국물리학회 2016 Current Applied Physics Vol.16 No.8

Recently carbon nanostructured materials are more attractive for the supercapacitor applications. Pure carbon nanotubes (CNTs) and double walled nitrogen doped carbon nanotubes (N-DWCNTs) have been synthesized for electrode material for the Supercapacitor applications. The N-DWCNTs were synthesized by Thermal Chemical Vapor Depositions (T-CVD) and they are coil shaped. The synthesized N-DWCNTs were characterized by powder X-ray diffraction (XRD) technique. The morphology of coil shaped NDWCNTs were revealed by the Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The Electrochemical performance of pure CNTs and N-DWCNTs was analyzed using Cyclic Voltammetry (CV) with 0.5 M H2SO4 electrolyte. It showed the good pseudocapacitance behavior for NDWCNTs. Electrochemical impedance spectroscopy (EIS) was measured for N-DWCNTs and showed the smaller charge transfer resistance (Rct e 7.731 U) which is much smaller than that of CNTs (23.69 U). The specific capacitance was measured for pure CNTs (23.40 F/g) and N-DWCNTs (51.29 F/g) with current density 0.125 A/g.

Population dynamics, age composition and survival of Downsiomyia nivea in relation to transmission of diurnally subperiodic filariasis

A.N. Shriram,K. Krishnamoorthy 한국응용곤충학회 2011 Journal of Asia-Pacific Entomology Vol.14 No.1

Diurnally subperiodicWuchereria bancrofti (DSPWB) filariasis is transmitted by the Downsiomyia nivea. In India,it is prevalent only in the Nicobar district of Andaman and Nicobar Islands. Knowledge of the population dynamics and bio-ecology of vectors is crucial to develop intervention measures. Entomological studies were performed for 12 months by collecting mosquitoes that landed on human baits for feeding in Teressa Island. Age composition, mosquitoes that had laid eggs at least once, finite rate of natural increase (λ) and vector survival reflecting the population dynamics of Do. nivea in relation to transmission of filariasis were estimated. A total of 3625 Do. nivea were collected. Changes in finite rate of increase (λN1) during favorable months indicate an increase in the vector population, suggesting the need for intensified intervention. The proportion ofmosquitoes completing more than one gonotrophic cycle was higher in months when λ was 1. Do. nivea abundance and its parous densities varied with seasons. Survival of Do. nivea (indicated by the proportion of parous mosquitoes)was lower in the pre-monsoon season than during the monsoon and post-monsoon seasons. The probability of the daily survival of Do. nivea through one gonotrophic cycle was 0.75, with a declining trend as age increased. The maximum transmission of DSPWB occurred during the pre-monsoon, followed by the late monsoon, postmonsoon and monsoon seasons. Perennial transmission is evident. Therefore intervention measures must be planned throughout the year. Prospects of vector control are limited due to the cryptic breeding and diurnal biting habits. Mass chemotherapy with a single dose of an antifilarial drug is a potential option for control.

An absolute displacement approach for modeling of sliding structures

Krishnamoorthy, A. Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

A procedure to analyse the space frame structure fixed at base as well as resting on sliding bearing using total or absolute displacement in dynamic equation is developed. In the present method, the effect of ground acceleration is not considered as equivalent force. Instead, the ground acceleration is considered as a known value in the acceleration vector at degree of freedom corresponding to base of the structure when the structure is in non-sliding phase. When the structure is in sliding phase, only a force equal to the maximum frictional resistance is applied at base. Also, in this method, the stiffness matrix, mass matrix and the damping matrix will not change when the structure enters from one phase to another. The results obtained from the present method using absolute displacement approach are compared with the results obtained from the analysis of structure using relative displacement approach. The applicability of the analysis is also demonstrated to obtain the response of the structure resting on sliding bearing with restoring force device.

Optimal utilization of service facility for a k-out-of-n system with repair by extending service to external customers in a retrial queue

A. Krishnamoorthy,Vishwanath C. Narayanan,T.G. Deepak 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.25 No.1

k-OUT-OF-n-SYSTEM WITH REPAIR : T-POLICY

Krishnamoorthy, A.,Rekha, A. 한국전산응용수학회 2001 The Korean journal of computational & applied math Vol.8 No.1

We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.

An absolute displacement approach for modeling of sliding structures

A. Krishnamoorthy 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

A procedure to analyse the space frame structure fixed at base as well as resting on sliding bearing using total or absolute displacement in dynamic equation is developed. In the present method, the effect of ground acceleration is not considered as equivalent force. Instead, the ground acceleration is considered as a known value in the acceleration vector at degree of freedom corresponding to base of the structure when the structure is in non-sliding phase. When the structure is in sliding phase, only a force equal to the maximum frictional resistance is applied at base. Also, in this method, the stiffness matrix, mass matrix and the damping matrix will not change when the structure enters from one phase to another. The results obtained from the present method using absolute displacement approach are compared with the results obtained from the analysis of structure using relative displacement approach. The applicability of the analysis is also demonstrated to obtain the response of the structure resting on sliding bearing with restoring force device.

OPTIMAL UTILIZATION OF SERVICE FACILITY FOR A k-OUT-OF-n SYSTEM WITH REPAIR BY EXTENDING SERVICE TO EXTERNAL CUSTOMERS IN A RETRIAL QUEUE

Krishnamoorthy, A.,Narayanan, Viswanath C.,Deepak, T.G. 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.25 No.1

In this paper, we study a k-out-of-n system with single server who provides service to external customers also. The system consists of two parts:(i) a main queue consisting of customers (failed components of the k-out-of-n system) and (ii) a pool (of finite capacity M) of external customers together with an orbit for external customers who find the pool full. An external customer who finds the pool full on arrival, joins the orbit with probability ${\gamma}$ and with probability $1-{\gamma}$ leaves the system forever. An orbital customer, who finds the pool full, at an epoch of repeated attempt, returns to orbit with probability ${\delta}\;(<\;1)$ and with probability $1-{\delta}$ leaves the system forever. We compute the steady state system size probability. Several performance measures are computed, numerical illustrations are provided.

Comparative structural analysis of lattice hybrid and tubular wind turbine towers

R. Kumaravel,A. Krishnamoorthy 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.30 No.1

This paper presents a comparative structural analysis of lattice hybrid tower with six legs with conventional tubular steel tower for an onshore wind turbine using finite element method. Usually a lattice hybrid tower will have a conventional industry standard \'L\' profile section for the lattice construction with four legs. In this work, the researcher attempted to identify and analyze the strength of six legged lattice hybrid tower designed with a special profile instead of four legged L profile. And to compare the structural benefits of special star profile with the conventional tubular tower. Using Ansys, a commercial FEM software, both static and dynamic structural analyses were performed. A simplified finite element model that represents the wind turbine tower was created using Shell elements. An ultimate load condition was applied to check the stress level of the tower in the static analysis. For the dynamic analysis, the frequency extraction was performed in order to obtain the natural frequencies of the tower.

Highly stable hierarchical p-CuO/ZnO nanorod/nanobranch photoelectrode for efficient solar energy conversion

Shaislamov, U.,Krishnamoorthy, K.,Kim, S.J.,Abidov, A.,Allabergenov, B.,Kim, S.,Choi, S.,Suresh, R.,Ahmed, W.M.,Lee, H.J. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.4

<P>In this study, we demonstrated a facile fabrication of highly stable CuO/ZnO nanorod-nanobranch based photocathode for photoelectrochemical hydrogen generation. Primary CuO nanorods (serving as a trunk) were synthesized via direct thermal oxidation of Cu nanorods that were grown by a template assisted electrodeposition method. Secondary ZnO nanobranches were uniformly grown on the entire surface of CuO nanorods via hydrothermal method. The prepared CuO/ZnO nanorod-nanobranch photoelectrode demonstrated an extremely high stability of 90% during a long term stability measurement. Morphological, optical and electrochemical characterizations have been carried out in order to understand the effects of ZnO nanorod branches on the overall electrochemical performance of the electrode. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.</P>

Safe implementation of transoral incisionless fundoplication as a new technique in a tertiary care center

Shivanand Bomman,Sofya Malashanka,Adil Ghafoor,David J. Sanders,Shayan Irani,Richard A. Kozarek,Andrew Ross,Michal Hubka,Rajesh Krishnamoorthi 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.5

Background/Aims: Transoral incisionless fundoplication (TIF) is an accepted anatomic treatment for gastroesophageal reflux disease in selected patients. In this report, we analyze our institution’s programmatic allocation of resources during the safe implementation of TIF as a new procedure. Methods: A retrospective analysis of all patients who underwent TIF from January 2020 to February 2021 at our institution was per- formed. The process of initially allocating the operating room (OR) with overnight admission and postoperative esophagram for added safety, and subsequently transitioning TIF to the endoscopy suite (ES) as an outpatient procedure was described. Patient safety and out- comes were evaluated during transition. Results: Thirty patients who underwent TIF were identified. The mean age was 51.2±16.0 years. TIF was performed in an OR in nine patients (30%) and 21 (70%) in the ES. All the OR patients were admitted overnight and had routine esophagogram. In contrast, four (19%) from the ES group required clinically-indicated admission and three (14.2%) required esophagram. The mean procedure dura- tion was significantly lower in the ES group (65.7 min vs. 84 min, p=0.02). Conclusions: A stepwise, resource-efficient process was described that allowed safe initiation of TIF as a new technique and its effec- tive transition to a fully outpatient procedure.