Nanostructured Bulk Ceramics (Part I)

Han, Young-Hwan,Mukherjee, Amiya K. The Korean Ceramic Society 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee's Lab at UC Davis. The following subjects will be introduced in detail in Part II, III, and IV. In Part II, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of $1400^{\circ}C$. This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

Nanostructured Bulk Ceramics (Part Ⅰ)

한영환,Amiya K. Mukherjee 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.3

The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations. The processing and characterization of ceramic nanocomposites, which produce bulk nanostructures with attractive mechanical properties, have been emphasized and introduced at Prof. Mukherjee’s Lab at UC Davis. The following subjects will be introduced in detail in Part ⅡI, Ⅲ, and Ⅳ. In Part Ⅱ, the paper will describe a three-phase alumina-based nanoceramic composite demonstrating superplasticity at a surprisingly lower temperature and higher strain rate. The next part will show that an alumina-carbon nanotube-niobium nanocomposite produced fracture toughness values that are three times higher than that of pure nanocrystalline alumina. It was possible to take advantage of both fiber-toughening and ductile-metal toughening in this investigation. In the fourth section, discussed will be a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of 1400℃ This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method. This allowed the sintering to be completed at significantly lower temperatures and during much shorter times. These improvements in mechanical properties will be discussed in the context of the results from the microstructural investigations.

A dragonfly inspired flapping wing actuated by electro active polymers

Mukherjee, Sujoy,Ganguli, Ranjan Techno-Press 2010 Smart Structures and Systems, An International Jou Vol.6 No.7

An energy-based variational approach is used for structural dynamic modeling of the IPMC (Ionic Polymer Metal Composites) flapping wing. Dynamic characteristics of the wing are analyzed using numerical simulations. Starting with the initial design, critical parameters which have influence on the performance of the wing are identified through parametric studies. An optimization study is performed to obtain improved flapping actuation of the IPMC wing. It is shown that the optimization algorithm leads to a flapping wing with dimensions similar to the dragonfly Aeshna Multicolor wing. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the IPMC wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

Simulation of tissue differentiation around acetabular cups: the effects of implant-bone relative displacement and polar gap

Mukherjee, Kaushik,Gupta, Sanjay Techno-Press 2014 Advances in biomechanics & applications Vol.1 No.2

Peri-acetabular bone ingrowth plays a crucial role in long-term stability of press-fit acetabular cups. A poor bone ingrowth often results in increased cup migration, leading to aseptic loosening of the implant. The rate of peri-prosthetic bone formation is also affected by the polar gap that may be introduced during implantation. Applying a mechano-regulatory tissue differentiation algorithm on a two-dimensional plane strain microscale model, representing implant-bone interface, the objectives of the study are to gain an insight into the process of peri-prosthetic tissue differentiation and to investigate its relationship with implant-bone relative displacement and size of the polar gap. Implant-bone relative displacement was found to have a considerable influence on bone healing and peri-acetabular bone ingrowth. An increase in implant-bone relative displacement from $20{\mu}m$ to $100{\mu}m$ resulted in an increase in fibrous tissue formation from 22% to 60% and reduction in bone formation from 70% to 38% within the polar gap. The increase in fibrous tissue formation and subsequent decrease in bone formation leads to weakening of the implant-bone interface strength. In comparison, the effect of polar gap on bone healing and peri-acetabular bone ingrowth was less pronounced. Polar gap up to 5 mm was found to be progressively filled with bone under favourable implant-bone relative displacements of $20{\mu}m$ along tangential and $20{\mu}m$ along normal directions. However, the average Young's modulus of the newly formed tissue layer reduced from 2200 MPa to 1200 MPa with an increase in polar gap from 0.5 mm to 5 mm, suggesting the formation of a low strength tissue for increased polar gap. Based on this study, it may be concluded that a polar gap less than 0.5 mm seems favourable for an increase in strength of the implant-bone interface.

Wind induced pressure on 'Y' plan shape tall building

Mukherjee, Sourav,Chakraborty, Souvik,Dalui, Sujit Kumar,Ahuja, Ashok Kumar Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5

This paper presents a comprehensive study of pressure developed on different faces of a 'Y' plan shape tall building using both numerical and experimental means. The experiment has been conducted in boundary layer wind tunnel located at Indian Institute of Technology Roorkee, India for flow condition corresponding to terrain category II of IS:875 (Part 3) - 1987, at a mean wind velocity of 10 m/s. Numerical study has been carried out under similar condition using computational fluid dynamics (CFD) package of ANSYS, namely ANSYS CFX. Two turbulence models, viz., $k-{\varepsilon}$ and Shear Stress Transport (SST) have been used. Good conformity among the numerical and experimental results have been observed with SST model yielding results of higher magnitude. Peculiar pressure distribution on certain faces has been observed due to interference effect. Furthermore, flow pattern around the model has also been studied to explain the phenomenon occurring around the model.

Rate Enhancement by Micelle Encapsulation for Oxidation of L-Glutamic Acid in Aqueous Media at Room Temperature

Mukherjee, Kakali,Saha, Bidyut Korean Chemical Society 2013 대한화학회지 Vol.57 No.4

Oxidation of glutamic acid is performed in aqueous acid media at $30^{\circ}C$ under the kinetic condition [glutamic acid]$_T{\gg}[Cr(VI)]_T$. Effect of combination of micellar catalyst (SDS, TX-100) and promoter (PA, bpy, phen) has been studied. Among the promoters phen accelerates the reaction most in aqueous media. But the rate acceleration is small in the case. Combination of promoter and catalyst produces much better result. Maximum rate enhancement occurs in presence of the combination of bpy and SDS.

Fight Detection in Hockey Videos using Deep Network

Mukherjee, Subham,Saini, Rajkumar,Kumar, Pradeep,Roy, Partha Pratim,Dogra, Debi Prosad,Kim, Byung-Gyu Korea Multimedia Society 2017 The journal of multimedia information system Vol.4 No.4

Understanding actions in videos is an important task. It helps in finding the anomalies present in videos such as fights. Detection of fights becomes more crucial when it comes to sports. This paper focuses on finding fight scenes in Hockey sport videos using blur & radon transform and convolutional neural networks (CNNs). First, the local motion within the video frames has been extracted using blur information. Next, fast fourier and radon transform have been applied on the local motion. The video frames with fight scene have been identified using transfer learning with the help of pre-trained deep learning model VGG-Net. Finally, a comparison of the methodology has been performed using feed forward neural networks. Accuracies of 56.00% and 75.00% have been achieved using feed forward neural network and VGG16-Net, respectively.

Solution processed, aligned arrays of TCNQ micro crystals for low-voltage organic phototransistor

Mukherjee, Biswanath,Mukherjee, Moumita,Sim, Kyoseung,Pyo, Seungmoon Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.6

<P>A simple approach is developed to prepare periodic arrays of large, elongated crystals of π-conjugated organic molecules, <I>viz</I>, 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) through a solution based method. The ordered crystalline array is successfully used to fabricate low-voltage organic phototransistors (OPT). The OPT with polymeric gate dielectric exhibits very stable n-type characteristics with a low threshold voltage (<0.5 V). Under illumination, the devices produce a current gain (I<SUB><I>light</I></SUB>/I<SUB><I>dark</I></SUB>) of 31 at <I>V</I><SUB><I>G</I></SUB> = 0.3 V. Photoswitching occurs within 10 ms and photosensitivity is greater than 1 mA W<SUP>−1</SUP> at low driving voltages and low optical powers. The drain current increases gradually with increasing the illumination intensity resulting in typical output FET characteristics. The one-step, solution-based, self-assembly method for highly ordered organic crystals in large area could have significant potential for future large-scale and low-cost optoelectronic devices. In addition, this study aims to aid the development of organic semiconductor materials with high quality crystalline structures for various optoelectronic applications.</P> <P>Graphic Abstract</P><P>A low voltage organic phototransistor (OPT) based on solution processed, highly ordered crystalline arrays of TCNQ exhibits excellent photosensitive field effect characteristics with a photo switching speed <10 ms. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm02513e'> </P>

Targeted inhibition of galectin 1 by thiodigalactoside dramatically reduces body weight gain in diet-induced obese rats

Mukherjee, R,Kim, S W,Park, T,Choi, M S,Yun, J W Nature Publishing Group 2015 International Journal of Obesity Vol.39 No.9

Background:Galectin 1 (GAL1), an animal lectin is well characterized in the context of cancer, tumor environment, but its physiological roles in obesity remain to be demonstrated. In this study, we investigated whether targeted inhibition of GAL1 prevents obesity based on the previous observations that GAL1 is highly expressed in adipose tissues of high-fat diet (HFD)-induced obese rats.Methods:Lipogenic capacity of Lgals1 knocked down adipocytes was evaluated by determining the expression levels of major lipogenic markers using real-time PCR and immunoblot analysis. GAL1 partner proteins were identified using co-immunoprecipitation followed by protein mass fingerprinting. Finally, inhibitory effect of GAL1 by thiodigalactoside (TDG) was assessed in adipocytes and HFD-induced obese rats.Results:Knockdown of GAL1-encoding gene (Lgals1) attenuated adipogenesis and lipogenesis in both 3T3-L1 and HIB1B adipocytes. Further, direct treatment with TDG, a potent inhibitor of GAL1, to cultured adipocytes in vitro significantly reduced fat accumulation. Our animal experiment revealed that intraperitoneal injection of TDG (5 mg kg<SUP>−1</SUP>) once per week for 5 weeks in Sprague-Dawley (SD) rats resulted in dramatic inhibition of HFD-induced body weight gain (27.3% reduction compared with HFD-fed controls) by inhibiting adipogenesis and lipogensis as well as by increasing expression of the proteins associated with thermogenesis and energy expenditure.Conclusion:GAL1 has an essential role in HFD-induced obesity development. From a clinical viewpoint, pharmaceutical targeting of GAL1 using TDG and other inhibitor compounds would be a novel therapeutic approach for the treatment of obesity.

Periodic arrays of organic crystals on polymer gate dielectric for low-voltage field-effect transistors and complementary inverter

Mukherjee, Biswanath,Shin, Tae Joo,Sim, Kyoseung,Mukherjee, Moumita,Lee, Junghyun,Kim, Sung Hoon,Pyo, Seungmoon Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.41

<P>Periodic arrays of highly oriented 7,7,8,8-tetracyanoquinodimethane (TCNQ) crystals, directly grown on a polymeric gate dielectric through a solution process, are used for the fabrication of a low-voltage organic field-effect transistor (OFET). Consequently, an organic complementary inverter using the TCNQ periodic array (<I>n</I>-channel) and pentacene (<I>p</I>-channel) is also reported. The TCNQ-based <I>n</I>-channel OFET exhibited very stable field-effect characteristics with low operational (2 V) and threshold voltages (<0.5 V). The highest field-effect carrier mobility in the saturation region was found to be 0.03 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>. Furthermore, the organic complementary inverter showed good response characteristics in the low-voltage regime. The swing range of <I>V</I><SUB>OUT</SUB> is same as <I>V</I><SUB>DD</SUB>, ensuring “zero” static power consumption in the digital logic circuit. For the inverter with <I>V</I><SUB>DD</SUB> = 2 V, the noise margin for low and high voltages are 1.0 V and 0.3 V, respectively. The logic threshold (<I>V</I><SUB>IN</SUB> = <I>V</I><SUB>OUT</SUB>) is 1.3 V and the maximum gain (−d<I>V</I><SUB>OUT</SUB>/d<I>V</I><SUB>IN</SUB>) of 4 is obtained at <I>V</I><SUB>IN</SUB> = 1.3 V.</P> <P>Graphic Abstract</P><P>A novel method to produce an ordered organic crystalline array and its use in fabricating high-performance low voltage OFET has been demonstrated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm01220c'> </P>