Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

Tiwary, C.S.,Kashyap, S.,Kim, D.H.,Chattopadhyay, K. Elsevier Sequoia 2015 Materials science & engineering. properties, micro Vol.639 No.-

Developments of aluminum alloys that can retain strength at and above 250<SUP>o</SUP>C present a significant challenge. In this paper we report an ultrafine scale Al-Fe-Ni eutectic alloy with less than 3.5at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6-8%. The yield stress under compression at 300<SUP>o</SUP>C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al-Al<SUB>3</SUB>Ni rod eutectic with spacing of ~90nm enveloped by a lamellar eutectic of Al-Al<SUB>9</SUB>FeNi (~140nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al-Al<SUB>3</SUB>Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al<SUB>3</SUB>Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

ON pc-RINGS

Tiwary, A.K.,Paramhans, S.A. Department of Mathematics 1977 Kyungpook mathematical journal Vol.17 No.2

Design and Analysis of Various Characteristics of a MEMS-Based PIB/CNT/LiNbO3 Multilayered SAW Sensor for CO2 Gas Detection

Ashish Tiwary,Shasanka Sekhar Rout,Basudeba Behera 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.6

This paper presents the design and analysis of a surface acoustic wave (SAW) sensor with a multilayer nanocomposite to detect carbon dioxide (CO2) gas. SAW resonator impacts the detection and identifi cation of hazardous gases that exist in the environment in an uncontrolled manner. These devices have the operational capability to work in a very extreme elevated temperature, pressure, and inert noxious atmosphere. The proposed work is intended to provide a two-dimensional model of a surface acoustic wave device/sensor and the most prominent solid material, carbon nanotube (CNT), which plays a vital role in the adsorption of volatile organic compounds. However, another miniature sensor has been designed with a potential material, an organic polymer, i.e., poly-isobutylene (PIB). Both the sensor model responses were examined for CO2 gas at room temperature. In this work, we have designed two diff erent resonator structures with the help of COMSOL Multiphysics. The proposed, designed models were patterned with interdigitated transducer electrodes made of aluminum material coated explicitly on top of the structure were used to analyze gas sensing behavior for CO2 gaseous elements. Here the proposed geometry provides resonance of 9.1524 MHz and anti-resonance of 9.2455 MHz for monolayer structure and resonance of 8.6447 MHz, and anti-resonance of 8.5201 MHz for multilayer structure. Comparatively, the second sensor PIB/CNT/LiNbO3 heterostructure pattern was also designed to be the best choice for the accurate and reliable measurement of the concentration of various gaseous elements based on a few parameters are discussed further.

태국과 한국을 중심으로 한 세계적 시각에서 불교의 배경

Kamakhiya Narain Tiwary 강원한국학연구원 2018 국제한국학저널 Vol.4 No.-

세계화 시대에 모든 나라가 서로 가까워지고 있다. 종교는 지정학적 협력의 여러 분야에서 상호 평등을 찾는 데 중요한 역할을 담당해 왔다. 이와 관련하여 불교는 가장 받아들여지는 종교 일뿐만 아니라 많은 아시아 국가에서 중요한 역할을 했다. 불교가 시작된 이래 인도의 많은 이웃 국가들은 불교문화에 더 많은 관심을 보였다. 이 논문은 세계적인 맥락에서 불교문화를 다룬다. 특히 태국과 한국 두 아시아 국가를 다루었다. 이 두 나라는 다양한 형태의 불교문화를 대표하지만, 대표적인 불교문화로 부상하고 있다. In this Era of globalization, all the countries are coming closer to each other. Religion has played an important role in finding mutual equality in different areas of geopolitical collaborations. In this regard, Buddhism is not only the most accepted religion, but also played an important role in many Asian countries. Since the inception of Buddhism, many neighboring countries of India showed deeper interest towards Buddhist culture. This paper deals with Buddhist culture in global context and particularly covers two Asian countries: Thailand and Korea. Although these two countries represent different forms of Buddhist culture, but they have been emerging as a representative Buddhist culture.

Post-Fire Exposure Behavior of Circular Concrete-fi lled Steel Tube Column under Axial Loading

Aditya Kumar Tiwary,Ashok Kumar Gupta 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.1

Concrete-fi lled steel tube (CFST) columns are a composite member which mainly consists of steel tube infi lled with concrete that are increasingly being used as load-carrying members these days. In construction industry, CFST columns are being preferred for the development of tall buildings and long-span bridges. This paper presents an experimental investigation on concrete-fi lled steel tube (CFST) columns which were post heated and were subjected to axial loading. The thickness of the casing steel was 4 mm and 5 mm and diameter was 100 mm, 125 mm and 150 mm and were infi lled with concrete of grade M30 which were used in the present study. This study also represents the behavior of CFST columns for two cooling regimes (annealing and quenching) after exposure to elevated temperatures of 600 °C and 800 °C. The results obtained from experimental analysis were compared to each other in terms of load-deformation pattern, ultimate load capacity, residual strength index, secant stiff ness and ductility index. The test results showed that as compared with water quenching, annealing is slightly better for post fi re cooling of CFST columns. Also, the results obtained by the experimental investigation were compared with each other on the basis of two cooling regimes.

AStudy on Optimization of Marigold Petal Yield, Pure Lutein, and Formulation of Free-Flowing Lutein Esters

Bipransh Kumar Tiwary,Anil Kumar,Ashis Kumar Nanda,Ranadhir Chakraborty 한국작물학회 2014 Journal of crop science and biotechnology Vol.17 No.3

The present study was conducted with the main objective to optimize petal yield from important marigold cultivars in WestBengal, and to standardize isolation of lutein from petals because these dietary xanthophylls are known to reduce the risks of agerelatedmacular degeneration (AMD) and cataracts. Six cultivars were studied viz. African marigold-Double (AFM-D), Africanmarigold-Single (AFM-S), African marigold-Orange (AFM-O), French marigold-Orange (FRM-O), French marigold-Double (FRMD),and LC (Local type), which withstand typical environmental conditions of northern West Bengal and produce flowers that do notvary in color and are relatively unaffected by pests and diseases. Lutein esters were extracted from milled marigold petals using nhexane. However, overall performance showed that LC is superior to the other cultivars. Pure lutein was obtained after saponificationwith 50% KOH. The re-crystallized lutein was characterized by UV-VIS, IR spectroscopy, and HPLC. A free-flowing lutein esterwas also formulated. This free-flowing lutein ester was found to be suitable to undergo commercialization or subsequent processing. An economic method for petal yield and isolation of lutein was thus standardized

Daubechies Complex Wavelet Transform Based Multilevel Shrinkage for Deblurring of Medical Images in Presence of Noise

Khare, A.,Tiwary, U.S.,Jeon, M. World Scientific 2009 International journal of wavelets, multiresolution Vol.7 No.5

Multilevel adaptive thresholding and shrinkage technique for denoising using Daubechies complex wavelet transform

Khare, A.,Tiwary, U.S.,Pedrycz, W.,Jeon, M. Maney Publishing 2010 The imaging science journal Vol.58 No.6

Compressive Behaviour of Diagonally Stiffened Concrete Filled Steel Tubular Stub Columns with Reinforcement Stiffeners

Harpreet Singh,Aditya Kumar Tiwary 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.2

Due to its superior strength and ductility, the utilisation of concrete-fi lled steel tube (CFST) columns has grown over the last few years. However, due to unequal lateral infl ation properties, infi ll concrete and steel tube slip against one another during early loading phases. This paper presented a novel type of CFST section, a diagonally stiff ened CFST column as a solution to this problem. It consists of a circular steel tube with stiff ening bars installed inside the outer steel tube from one top end to the diagonally opposite bottom end. The suggested section is presented using various stiff ening strategies, including binary, tertiary, and quaternary arrangements. The eff ectiveness of the suggested column section under an axial load is examined using fi nite element (FE) modelling, and the validation of the FE model was established using experimental testing carried out by previous researchers on unstiff ened and stiff ened CFST columns. Analysis was done on specimens of diagonally stiff ened CFST columns to evaluate the load-carrying capacity, load vs deformation behaviour, stress distribution, and failure pattern. According to the fi ndings of this study, CFST sections with diagonal stiff eners have higher ultimate load capacity than unstiff ened CFST columns. Stiff ening bars increase the ductility of brittle infi ll concrete and eliminate localised steel tube buckling. It was recommended that the number of stiff eners be altered to even numbers since odd numbers of stiff eners can cause asymmetry in the section, which can increase the concentration of stress.

An Adaptively Accelerated Bayesian Deblurring Method with Entropy Prior

Singh, Manoj Kumar,Tiwary, Uma Shanker,Kim, Yong-Hoon Hindawi Publishing Corporation 2008 EURASIP journal on advances in signal processing Vol.2008 No.1

<P>The development of an efficient adaptively accelerated iterative deblurring algorithm based on Bayesian statistical concept has been reported. Entropy of an image has been used as a “prior” distribution and instead of additive form, used in conventional acceleration methods an exponent form of relaxation constant has been used for acceleration. Thus the proposed method is called hereafter as adaptively accelerated maximum a posteriori with entropy prior (AAMAPE). Based on empirical observations in different experiments, the exponent is computed adaptively using first-order derivatives of the deblurred image from previous two iterations. This exponent improves speed of the AAMAPE method in early stages and ensures stability at later stages of iteration. In AAMAPE method, we also consider the constraint of the nonnegativity and flux conservation. The paper discusses the fundamental idea of the Bayesian image deblurring with the use of entropy as prior, and the analytical analysis of superresolution and the noise amplification characteristics of the proposed method. The experimental results show that the proposed AAMAPE method gives lower RMSE and higher SNR in 44% lesser iterations as compared to nonaccelerated maximum a posteriori with entropy prior (MAPE) method. Moreover, AAMAPE followed by wavelet wiener filtering gives better result than the state-of-the-art methods.</P>