Active control of delaminated composite shells with piezoelectric sensor/actuator patches

Nanda, Namita,Nath, Y. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.2

Present study deals with the development of finite element based solution methodology to investigate active control of dynamic response of delaminated composite shells with piezoelectric sensors and actuators. The formulation is based on first order shear deformation theory and an eight-noded isoparametric element is used. A coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. A simple negative feedback control algorithm coupling the direct and converse piezoelectric effects is used to actively control the dynamic response of delaminated composite shells in a closed loop employing Newmark's time integration scheme. The validity of the numerical model is demonstrated by comparing the present results with those available in the literature. A number of parametric studies such as the locations of sensor/actuator patches, delamination size and its location, radius of curvature to width ratio, shell types and loading conditions are carried out to understand their effect on the transient response of piezoceramic delaminated composite shells.

Poster Session : PS 0359 ; Epidemiology and Public Health : The Prevalence of Unidentifi ed Disease in Cipto Mangunkusumo National Hospital Year 2010 and Sociodemographic Factors Related

( Nanda Lucky Prasetya ),( Muchtaruddin Mansyur ),( Andy Omega ),( Adam Prabata ),( Aghnia Permatasari ),( Ayudhia Kartika ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Diagnosing is a main verb in medicine. Diagnosis is set based on clinical reasoning. Factors contributing in clinical reasoning are clinical competency and other factors related with physician; sociodemographical factor and others related with patients; diagnostic facility and others related to health policy. Methods: This descriptive-analytic cross sectional research was done in 904 medical record of adult polyclinic patient, using proportional random sampling and chi square analysis to show how many disease could not be identifi ed, and what factors signifi cantly contribute. Results: Although Cipto Mangunkusumo Hospital is a referral centre and national hospital, our research found that there is 5, 60% (n =51) of polyclinic cases are diagnosed as Unidentifi ed Disease (ICD10: R69), ranked at 4th after Senile Cataract, Hypertension, and DM Type 2. Their 84, 30% (n=43) are from Internal Medicine Department, mainly from Unspecifi ed Division (patient of more than one division or unmentioned) for 63% (n=27), and Pulmonology Division for 33% (n=14). At this research also, we were going to fi nd the connection between Unidentified Disease and one of the factors contributing in clinical reasoning: Sociodemographical Factors. The variables are age, gender, educational level, employment, and health insurance. We found no variable is signifi cantly related to Unidentifi ed Disease (all p>0, 05). Conclusions: Hence, the other factors beside Sociodemographical Factors have contribution to clinical reasoning that is set up to Unidentifi ed Disease: physician`s factors (clinical competency and others), diagnostic facility, and others. However, which one defi nitely contributing is still questionable as CM Hospital is educational hospital; have thousands of doctors consist of consultants, residents, and others; one of the most complete diagnostic facility in nation. Further research shall be done to defi ne this relatively big number of disease which still being unidentifi ed in national referral hospital.

Identification of Novel Source of Resistance and Differential Response of Allium Genotypes to Purple Blotch Pathogen, Alternaria porri (Ellis) Ciferri

Nanda, Satyabrata,Chand, Subodh Kumar,Mandal, Purander,Tripathy, Pradyumna,Joshi, Raj Kumar The Korean Society of Plant Pathology 2016 Plant Pathology Journal Vol.32 No.6

Purple blotch, caused by Alternaria porri (Ellis) Cifferi, is a serious disease incurring heavy yield losses in the bulb and seed crop of onion and garlic worldwide. There is an immediate need for identification of effective resistance sources for use in host resistance breeding. A total of 43 Allium genotypes were screened for purple blotch resistance under field conditions. Allium cepa accession 'CBT-Ac77' and cultivar 'Arka Kalyan' were observed to be highly resistant. In vitro inoculation of a selected set of genotypes with A. porri, revealed that 7 days after inoculation was suitable to observe the disease severity. In vitro screening of 43 genotypes for resistance to A. porri revealed two resistant lines. An additional 14 genotypes showed consistent moderate resistance in the field as well as in vitro evaluations. Among the related Allium species, A. schoenoprasum and A. roylei showed the least disease index and can be used for interspecific hybridization with cultivated onion. Differential reaction analysis of three A. porri isolates (Apo-Chiplima, Apn-Nasik, Apg-Guntur) in 43 genotypes revealed significant variation among the evaluated Allium species (P = 0.001). All together, the present study suggest that, the newly identified resistance sources can be used as potential donors for ongoing purple blotch resistance breeding program in India.

Damage assessment from curvature mode shape using unified particle swarm optimization

Nanda, Bharadwaj,Maity, Damodar,Maiti, Dipak Kumar Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.2

A two-step procedure to detect and quantify damages in structures from changes in curvature mode shapes is presented here. In the first step the maximum difference in curvature mode shapes of the undamaged and damaged structure are used for visual identification of the damaged internal-substructure. In the next step, the identified substructures are searched using unified particle swarm optimization technique for exact identification of damage location and amount. Efficiency of the developed procedure is demonstrated using beam like structures. This methodology may be extended for identifying damages in general frame structures.

Layer-adapted meshes for solute dispersion in a steady flow through an annulus with wall absorption: Application to a catheterized artery

Nanda Poddar,Kajal Kumar Mondal,Niall Madden 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.1

This paper describes the longitudinal dispersion of passive tracer molecules injected in a steady, fully developed, viscous, incompressible, laminar flow through an annular pipe with a first order heterogeneous boundary absorption at the outer wall, numerically using layer-adapted meshes. The model is based on steady advection-diffusion equation with Dirichlet and Robin boundary conditions. The solutions are discussed in the form of iso-concentration contours of the tracer molecules in the vertical plane. An artanh transformation is used to convert the infinite domain into a finite one. A combination of central finite difference and 2-point upwind scheme is adopted to solve the governing advection-diffusion equation. It is shown that how the mixing of tracers is affected by the shear flow, aspect ratio and the first-order boundary absorption. When the flow becomes convection dominated, the monotone finite difference on a uniform mesh does not work properly, so a layer-adapted mesh, namely a “Shishkin” mesh, is used to capture the layer phenomena at the different downstream stations. The present results are compared with existing experimental and numerical data and we have earned an excellent agreement with them. It is observed that, due to the use of layer adapted mesh, we have achieved a better agreement with the experimental data than some other previous results available in the literature, especially in the closest downstream location. The results of this study are likely to be of interest to understand the basic mechanism of dispersion process of solute in blood through a catheterized artery with an absorptive arterial wall.

Nitrophenyl Functionalization of Carbon Nanotubes and Its Effect on Properties of MWCNT/LCP Composites

Nanda Gopal Sahoo,Henry Kuo Feng Cheng,Hongqian Bao,Siew Hwa Chan,Lin Li,Jianhong Zhao 한국고분자학회 2011 Macromolecular Research Vol.19 No.7

Multiwalled carbon nanotubes (MWCNTs) were functionalized on their sidewalls with p-nitrophenyl (C_6H_4NO_2) to make MWCNTs compatible with liquid crystalline polymer (LCP) through a specific interaction with LCP. This study examined the rheological, morphological, mechanical, dynamic mechanical, and thermal properties of LCP in detail with a variation of the nitrophenyl-functionalized MWCNTs in the LCP matrix. A higher complex viscosity, storage, and loss modulus were observed in the nitrophenyl-functionalized MWCNTs/LCP composites than the composites with the same loading of raw MWCNTs. The nitrophenyl groups attached to the MWCNTs improved their dispersion and interfacial adhesion with the LCP matrix, which was confirmed by field emission scanning electron microscopy (FESEM). As a result, the incorporation of the nitrophenyl-functionalized MWCNTs effectively enhanced the mechanical and thermal stability of the LCP.

Vibration Based Structural Damage Detection Technique using Particle Swarm Optimization with Incremental Swarm Size

Nanda, Bharadwaj,Maity, Damodar,Maiti, Dipak Kumar The Korean Society for Aeronautical and Space Scie 2012 International Journal of Aeronautical and Space Sc Vol.13 No.3

A simple and robust methodology is presented to determine the location and amount of crack in beam like structures based on the incremental particle swarm optimization technique. A comparison is made for assessing the performance of standard particle swarm optimization and the incremental particle swarm optimization technique for detecting crack in structural members. The objective function is formulated using the measured natural frequency of the intact structure and the frequency obtained from the finite element simulation. The outcomes of the simulated results demonstrate that the developed method is capable of detecting and estimating the extent of damages with satisfactory precision.

Study on structural damping of aluminium using multi-layered and jointed construction

Nanda, B.K.,Behera, A.K. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.6

In this work, the mechanism of damping and its theoretical evaluation for layered aluminium cantilever structures jointed with a number of equispaced connecting bolts under an equal tightening torque have been considered. Extensive experiments have been conducted on a number of specimens for comparison with numerical results. Intensity of interface pressure, its distribution pattern, dynamic slip ratio and kinematic coefficient of friction at the interfaces, relative spacing of the connecting bolts, frequency and amplitude of excitation are found to play a major role on the damping capacity of such structures. It is established that the damping capacity of structures jointed with connecting bolts can be improved largely with an increase in number of layers maintaining uniform intensity of pressure distribution at the interfaces. Thus the above principle can be utilized in practice for construction of aircraft and aerospace structures effectively in order to improve their damping capacity which is one of the prime considerations for their design.

Synthesis of polyurethane nanocomposites of functionalized carbon nanotubes by in-situ polymerization methods

Nanda Sahoo,Jae Whan Cho,Hyang Hwa So,정용채 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I

Carboxylic functionalized multi-walled carbon nanotubes (MWNTs) have been incorporated to segmented polyurethane block copolymer (PU) to demonstrate the effect of the chemical functionalization of MWNTs on the thermal, morphological and mechanical properties of MWNT-reinforced nanocomposites. Polyurethane was synthesized in a two-step process from a reaction of 4,4$^\prime$-methylene bis(phenylisocyanate), poly($\varepsilon$-caprolactone)diol, and 1,1,1-tris(hydroxymethyl)propane as a chain extender. The nature of the interaction between chemical groups on the PU and the MWNT surface was probed by measuring the extent of the shift in absorbing wavelength of key groups in the polymer and on the MWNT after mixing of these components. Mechanical properties of the PU-MWNT nanocomposites were assessed as a function of MWNT concentration and dispersion of MWNT in PU matrix. Scanning electron microscopy observation indicated that homogeneous dispersion of functionalized MWNTs throughout PU matrix and strong interfacial adhesion between functionalized MWNTs and the matrix were achieved in PU nanocomposites, which brought an enhancement in the mechanical properties. MWNTs improved the thermal stability of the nanocomposites, as evidenced by thermogravimetric analysis.

Raman spectrum of graphene with its versatile future perspectives

Nanda, S.S.,Kim, M.J.,Yeom, K.S.,An, S.S.A.,Ju, H.,Yi, D.K. Elsevier Scientific Pub. Co 2016 Trends in analytical chemistry Vol.80 No.-

<P>Raman spectroscopy is performing as a powerful analytical technique for qualitative and quantitative analysis of graphene and graphene-related compounds. Graphene and graphene-related compounds exhibit intense Raman vibrations. Raman spectroscopic techniques for determination of several graphene layers, and the quality and type of edges, disorders, and functional groups in graphene and graphene-related compounds are of increasing importance. Herein, we review the developments and discuss the future direction and various questions relevant to Raman spectroscopic analysis of graphene and graphenerelated compounds. An update of the basic concepts underlying the Raman spectroscopy of graphene is presented and conclusions regarding this matter are provided. The biomedical and physical applications of Raman spectroscopy of graphene are evaluated. The chemical enhancement of the Raman signals and studies of these enhancements are known as Surface enhanced Raman spectroscopy (SERS) and Tip enhanced Raman spectroscopy (TERS). Different mechanisms of achieving chemical enhancement of the Raman signal of the graphene surface and study of these enhancements through Raman spectroscopy are discussed in this critical review illustrating the growth in the use of Raman spectroscopy in graphene research. (C) 2016 Elsevier B.V. All rights reserved.</P>