排序方式: 共有28条查询结果,搜索用时 0 毫秒
1.
Karthikeyan Duraisamy James D. Baeder Jian-Guo Liu 《Journal of scientific computing》2003,19(1-3):139-162
A new class of implicit high-order non-oscillatory time integration schemes is introduced in a method-of-lines framework. These schemes can be used in conjunction with an appropriate spatial discretization scheme for the numerical solution of time dependent conservation equations. The main concept behind these schemes is that the order of accuracy in time is dropped locally in regions where the time evolution of the solution is not smooth. By doing this, an attempt is made at locally satisfying monotonicity conditions, while maintaining a high order of accuracy in most of the solution domain. When a linear high order time integration scheme is used along with a high order spatial discretization, enforcement of monotonicity imposes severe time-step restrictions. We propose to apply limiters to these time-integration schemes, thus making them non-linear. When these new schemes are used with high order spatial discretizations, solutions remain non-oscillatory for much larger time-steps as compared to linear time integration schemes. Numerical results obtained on scalar conservation equations and systems of conservation equations are highly promising. 相似文献
2.
Muhammad Zubair Navaneethan Duraisamy Kyung Hyun Choi Myung Teak Hyun 《Journal of Materials Science: Materials in Electronics》2014,25(2):1033-1039
The conductivity of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) was improved by pressing the PEDOT:PSS thin film using roll to plate system. PEDOT:PSS thin film was deposited on polyethylene terephthalate using electrohydrodynamics atomization technique. The physico-chemical properties of the pressed thin film at different loads were compared with an un-pressed sample. The electrical properties show that the film conductivity has been increased by four times. An optimized pressing load was found to have good conductivity and transmittance of the thin film. A hybrid device (PEDOT:PSS/F8BT/ZnO/Ag) was fabricated using layer by layer method with PEDOT:PSS as anode. The I–V characterization showed that the device with pressed PEDOT:PSS showed higher current densities. The results give a promising future of PEDOT:PSS in electronics device applications using printed electronics techniques. 相似文献
3.
Swami Durai Senthil Kumar Duraisamy Balaganesh Thirukrishna J. T. 《International Journal of Wireless Information Networks》2023,30(1):103-110
International Journal of Wireless Information Networks - Wireless Sensor Networks are often to perform autonomous sensing and controlling the real world objects through the sensor nodes across the... 相似文献
4.
The objective of this study is to investigate the impact of human exposure due to electromagnetic fields and to reduce the specific absorption rate (SAR). This work focuses on the implementation of different electromagnetic shield materials such as conductive materials, dielectric materials, ferrite materials, and metamaterials that are currently used for SAR reduction. The experimental analysis is performed with the global system for mobile communication (GSM) dipole antenna operating at 900 MHz as its radiation source. The designed dipole is placed in front of a cube with similar dielectric properties of human tissue. The computation, implementation, and evaluation are performed by using the method of moments. Further calculation of SAR reduction factor (SRF), SAR 1 g, gain, directivity, and beamwidth are estimated for 15 different shield materials. There is a need for an ideal shield material that could reduce SAR and does not compromise the performance of the radiation structure. This work investigates and proposes the nanomaterials and composites as suitable shield materials for SAR reduction. This novel approach of implementation of nanomaterials has proved to increase the SRF over 90% than conventional reduction materials. In addition, gain and directivity are also increased by 50% than the existing shield materials. The currently used materials are compared with the proposed nanomaterials, and the results are analyzed. The results indicate that the nanomaterials and its composites are ideal shield material for SAR reduction. 相似文献
5.
In this paper a fuzzy transportation problem under a fuzzy environment is solved using octagonal fuzzy numbers. The transportation problem is significant and has been widely studied in the field of applied mathematics to solve a system of linear equations in many applications in science. Systems of concurrent linear equations play a vital major role in operational research. The main perspective of this research paper is to find out the minimum amount of transportation cost of some supplies through a capacitated network formerly the availability and the demand notes are octagonal fuzzy numbers. Octagonal fuzzy numbers are used and showed a membership function. To illustrate this method, a fuzzy transportation problem is solved by using octagonal fuzzy numbers using the ranking technique. It is shown that it is the best optimal solution and it is demonstrated with a numerical example. 相似文献
6.
Srinath Doss Jothi Paranthaman Suseendran Gopalakrishnan Akila Duraisamy Souvik Pal Balaganesh Duraisamy Chung Le Van Dac-Nhuong Le 《计算机、材料和连续体(英文)》2021,66(2):1577-1593
In the healthcare system, the Internet of Things (IoT) based distributed systems play a vital role in transferring the medical-related documents and information among the organizations to reduce the replication in medical tests. This datum is sensitive, and hence security is a must in transforming the sensational contents. In this paper, an Evolutionary Algorithm, namely the Memetic Algorithm is used for encrypting the text messages. The encrypted information is then inserted into the medical images using Discrete Wavelet Transform 1 level and 2 levels. The reverse method of the Memetic Algorithm is implemented when extracting a hidden message from the encoded letter. To show its precision, equivalent to five RGB images and five Grayscale images are used to test the proposed algorithm. The results of the proposed algorithm were analyzed using statistical methods, and the proposed algorithm showed the importance of data transfer in healthcare systems in a stable environment. In the future, to embed the privacy-preserving of medical data, it can be extended with blockchain technology. 相似文献
7.
Duraisamy Sivaprahasam A. M. Sriramamurthy M. Vijayakumar G. Sundararajan Kamanio Chattopadhyay 《Metallurgical and Materials Transactions B》2010,41(4):841-856
Condensation from the vapor state is an important technique for the preparation of nanopowders. Levitational gas condensation
is one such technique that has a unique ability of attaining steady state. Here, we present the results of applying this technique
to an iron-copper alloy (96Fe-4Cu). A qualitative model of the process is proposed to understand the process and the characteristics
of resultant powder. A phase diagram of the alloy system in the liquid–vapor region was calculated to help understand the
course of condensation, especially partitioning and coring during processing. The phase diagram could not explain coring in
view of the simultaneous occurrence of solidification and the fast homogenization through diffusion in the nanoparticles;
however, it could predict the very low levels of copper observed in the levitated drop. The enrichment of copper observed
near the surface of the powder was considered to be a manifestation of the lower surface energy of copper compared with that
of iron. Heat transfer calculations indicated that most condensed particles can undergo solidification even when they are
still in the proximity of the levitated drop. It helped us to predict the temperature and the cooling rate of the powder particles
as they move away from the levitated drop. The particles formed by the process seem to be single domain, single crystals that
are magnetic in nature. They, thus, can agglomerate by forming a chain-like structure, which manifests as a three-dimensional
network enclosing a large unoccupied space, as noticed in scanning electron microscopy and transmission electron microscopy
studies. This also explains the observed low packing density of the nanopowders. 相似文献
8.
Jiun-Jen Chen Ya-Ting Chen Duraisamy Senthil Raja Yu-Hao Kang Pen-Chang Tseng Chia-Her Lin 《Science and Technology of Advanced Materials》2015,16(5)
Three new isostructural metal–organic frameworks (MOFs), [V(OH)(NDC)] (1), [Cr(OH)(NDC)] (2), and [Ga(OH)(NDC)] (3) have been synthesized hydrothermally using 1,4-naphthalene dicarboxylate (NDC) as the linker. These MOFs (1, 2 and 3) have been used as a template for the synthesis of metal-oxide-inserted nanoporous carbon materials. The newly synthesized MOFs and the resulting porous carbon hybrid functional materials have been characterized using powder x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopic analysis. Results show that compounds 2 and 3 form their respective metal oxide nanoparticles on the surface of the carbon materials during carbonization at 800 °C. The gas sorption properties of the new MOFs and their corresponding carbon frameworks have been reported. 相似文献
9.
Prakasam Thirumurugan Duraisamy Muralidharan Paramasivan T. Perumal 《Dyes and Pigments》2009,81(3):245-253
A simple and facile method for the synthesis of 2,3-bis[(E)-2-aryl vinyl]-quinoxaline and 2,3-bis[(E)-2-aryl vinyl]-pyrido(2,3-b)pyrazine is described. Condensation of cinnamils with 1,2-diaminobenzene and 2,3-diaminopyridine in water using conventional heating and microwave irradiation afforded high yields (71–92%) of 2,3-bis[(E)-2-aryl vinyl]-quinoxalines and 2,3-bis[(E)-2-arylvinyl]-pyrido(2,3-b)pyrazines. The photophysical properties of the resultant quinoxaline and pyrazine derivatives were studied; the pyridopyrazine derivatives were found to exhibit halochromism. 相似文献
10.
Karthikeyan Rajagopal Anitha Karthikeyan Prakash Duraisamy Riessom Weldegiorgis Goitom Tadesse 《Asian journal of control》2019,21(1):184-193
The paper investigates the complex nonlinear behavior of a fractional order four dimension power system (FOFDPS). The discrete mathematical model of the FOFDPS is derived and presented. The equilibrium points along with the Eigen values of commensurate and incommensurate FOFDPS are presented. The existence of chaotic oscillations are supported by a positive Lyapunov exponent. Bifurcation plots are derived for both parameters and fractional orders to show the impact of the same on the dynamic behavior of FOFDPS. Having shown the existence of such complex behaviors in the FOFDPS, we present an adaptive fractional order sliding mode control (FOASMC) to suppress the chaotic oscillations. Numerical results are presented to support the theoretical results. 相似文献