Mechanical performance of mono and hybrid synthetic fibers engineered cementitious composites with silica fume

K. Yuvaraj,M. Sakthivel,M. Dhivakar Karthick,T. Pradeep,M. Veerapathran,S. Gowtham 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.2

An attempt was undertaken to elevate the efficacy of Engineered Cementitious Composites (ECC) mixes by inclusion ofsilica fume alongside mono fiber and hybrid fiber in this study. Totally, six mixes were prepared with low modulus and highmodulus fiber. The initial three mixtures consist of mono fiber engineered cementitious composites (MFECC), incorporatingPoly Vinyl Alcohol (PVA), Polypropylene (PP), and Glass fiber, each with a 2% volume fraction. The remaining three mixtureswere formulated as hybrid fiber engineered cementitious composites (HFECC), combining PVA (1%) and PP (1%), PP (1%)and Glass (1%), and lastly, PVA (1%) and Glass (1%). In addition, all six mixtures were consistently maintained with a fixedcomposition comprising 40% silica fume, 30% fly ash, 80% M-sand, a water-to-binder ratio of 0.35, and 1% superplasticizer. The findings suggest that within the examined compositions, MFECC reinforced with 2.0% PVA fiber and HFECC reinforcedwith 1% PVA fiber and 1% glass fiber exhibit more significant strength characteristics than other mixtures.

Transfer Learning Based Real-Time Crack Detection Using Unmanned Aerial System

Yuvaraj, N.,Kim, Bubryur,Preethaa, K. R. Sri Council on Tall Building and Urban Habitat Korea 2020 International journal of high-rise buildings Vol.9 No.4

Monitoring civil structures periodically is necessary for ensuring the fitness of the structures. Cracks on inner and outer surfaces of the building plays a vital role in indicating the health of the building. Conventionally, human visual inspection techniques were carried up to human reachable altitudes. Monitoring of high rise infrastructures cannot be done using this primitive method. Also, there is a necessity for more accurate prediction of cracks on building surfaces for ensuring the health and safety of the building. The proposed research focused on developing an efficient crack classification model using Transfer Learning enabled EfficientNet (TL-EN) architecture. Though many other pre-trained models were available for crack classification, they rely on more number of training parameters for better accuracy. The TL-EN model attained an accuracy of 0.99 with less number of parameters on large dataset. A bench marked METU dataset with 40000 images were used to test and validate the proposed model. The surfaces of high rise buildings were investigated using vision enabled Unmanned Arial Vehicles (UAV). These UAV is fabricated with TL-EN model schema for capturing and analyzing the real time streaming video of building surfaces.

Conducting Copolymer/ZnO Nanocomposite: Synthesis, Characterization, and Its Photocatalytic Activity for the Removal of Pollutants

Sivakumar, K.,Senthil Kumar, V.,Shim, Jae-Jin,Haldorai, Yuvaraj Informa UK (TaylorFrancis) 2014 Synthesis and reactivity in inorganic, metal-organ Vol.44 No.10

Photocatalytic and Antimicrobial Activities of Poly(aniline-co-o-anisidine)/Zinc Oxide Nanocomposite

Sivakumar, K.,Kumar, V. Senthil,Shim, Jae-Jin,Haldorai, Yuvaraj Chemic Publishing Company 2014 Asian Journal of Chemistry Vol.26 No.2

<P>The conjugated poly(aniline-co-o-anisidine)/zinc oxide,[poly(Ani-co-oAs)/ZnO] nanocomposite was prepared by in-situ chemical oxidative polymerization of comonomers with ZnO nanoparticles and :applied as a photocatalyst for the degradation of methylene blue dye. Scanning electron microscopy, transmission electron microscopy:X-ray diffraction, Fourier transform infrared spectroscopy and UV-visible spectroscopy measurements were used to characterize the resulting pure copolymer and nanocomposite. Transmission electron microscopy analysis showed that the nano-particles with amean diameter of 15-25 nm were dispersed in the copolymer matrix. Thermogravimetric analysis indicated that the nanocomposite had a higher decomposition temperature than the pure copolymer. The conductivity measurements showed the resulting nanocomposite possessed higher conductivity as compared to the pure copolymer. The photocatalytic activity results indicated the degradation of methylene blue dye by 97%, over the surface of nanocomposite catalyst under UV-irradiation for 3 h. The nanocomposite exhibited good antimicrobial activity against the microbial species and the dear zone diameter Of the microbial inhibition is correlated to the antimicrobial activity of nanocomposite</P>

Glassy carbon electrode modified by gold nanofibers decorated iron metal–organic framework nanocomposite for voltammetric determination of acetaminophen

Kavya K. V.,Muthu Dinesh,Varghese Stella,Pattappan Dhanaprabhu,Kumar R. T. Rajendra,Haldorai Yuvaraj 한국탄소학회 2022 Carbon Letters Vol.32 No.6

In this work, a nanocomposite containing gold (Au) nanofibers decorated iron-metal–organic framework (Fe-MOF) was successfully synthesized for electrochemical detection of acetaminophen (AAP). The as-synthesized Au@Fe-MOF nanocomposite was confirmed by various characterization techniques. Morphological analysis showed that the Au nanofibers with an average size of less than 10 nm were dispersed on the Fe-MOF. Cyclic voltammetric analysis showed that the Au@Fe-MOF nanocomposite showed well-defined redox peaks with higher current than that of GCE and Fe-MOF. The Au@Fe-MOF/GCE exhibited a linear range, sensitivity, and detection limit of 0.5–18 µM, 4.95 µM/µA/cm2, and 0.12 µM, respectively. The Au@Fe-MOF/GCE showed a very low response for the interference materials. The real sample analysis revealed that the Au@Fe-MOF/GCE showed good recovery towards the AAP in urine and paracetamol. Therefore, the developed sensor can be used for quality control of AAP.

A Sustainable Graphene Aerogel Capable of the Adsorptive Elimination of Biogenic Amines and Bacteria from Soy Sauce and Highly Efficient Cell Proliferation

Bajpai, Vivek K.,Shukla, Shruti,Khan, Imran,Kang, Sung-Min,Haldorai, Yuvaraj,Tripathi, Kumud Malika,Jung, SungHoon,Chen, Lei,Kim, TaeYoung,Huh, Yun Suk,Han, Young-Kyu American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.47

<P>A graphene aerogel (GA) with a three-dimensional (3D) structure, ultra-lightweight nature, and high hydrophobicity was simply fabricated by the one-step pyrolysis of glucose and ammonium chloride. The as-synthesized GA exhibited a 3D interconnected microporous architecture with a high surface area of ∼2860 m<SUP>2</SUP> g<SUP>-1</SUP> and pore volume of 2.24 cm<SUP>3</SUP> g<SUP>-1</SUP>. The hydrophobic GA (10 mg 100 mL<SUP>-1</SUP>) demonstrated rapid and excellent adsorption performance for the removal of food toxins such as various biogenic amines (histamine, cadaverine, and spermine) and the hazardous bacterium <I>Staphylococcus aureus</I> (a food contaminant and a cause of poor wound healing) from a liquid matrix with a maximum simultaneous adsorption capacity for multiple biogenic amines of >85.19% (histamine), 74.1% (cadaverine), and 70.11% (spermidine) and a 100% reduction in the viable cell count of <I>S. aureus</I> within 80 min of interaction. The outstanding adsorption capacity can be attributed to a highly interconnected porous network in the 3D architecture and a high surface-to-volume ratio. A case study using soy sauce spiked with multiple biogenic amines showed successful removal of toxins with excellent recyclability without any loss in absorption performance. Biocompatibility of the GA in terms of cell viability was observed even at high concentrations (83.46% and 75.28% at 25 and 50 mg mL<SUP>-1</SUP>, respectively). Confirmatory biocompatibility testing was conducted via live/dead cell evaluation, and the morphology of normal lung epithelial cells was examined via scanning electron microscopy showed no cellular shrinkage. Moreover, GA showed excellent removal of live colonies of <I>S. aureus</I> from the food matrix and immunoblotting analysis showed elevated protein expression levels of β-catenin and α-SMA (α-smooth muscle actin). The biocompatible sugar-based GA could simultaneously adsorb multiple biogenic amines and live bacteria and was easy to regenerate via simple separation due to its high floatability, hydrophobicity, surface area, and porosity without any structural and functional loss, making it especially relevant for food safety and biomedical applications.</P> [FIG OMISSION]</BR>

Electrochemical coupled immunosensing platform based on graphene oxide/gold nanocomposite for sensitive detection of <i>Cronobacter sakazakii</i> in powdered infant formula

Shukla, Shruti,Haldorai, Yuvaraj,Bajpai, Vivek K.,Rengaraj, Arunkumar,Hwang, Seung Kyu,Song, Xinjie,Kim, Myunghee,Huh, Yun Suk,Han, Young-Kyu Elsevier 2018 Biosensors & bioelectronics Vol.109 No.-

<P><B>Abstract</B></P> <P>A sensitive electrochemical immunosensing platform for the detection of <I>Cronobacter sakazakii</I> was developed using a graphene oxide/gold (GO/Au) composite. Transmission electron microscopy showed that the Au nanoparticles, with an average size of < 30 nm, were well dispersed on the GO surface. For the detection of <I>C. sakazakii</I>, a polyclonal anti-<I>C. sakazakii</I> antibody (IgG) was covalently immobilized to the Au nanoparticles on the surface of the GO/Au composite coated glassy carbon electrode (GCE). The electrochemical sensing performance of immunofunctionalized GCE was characterized by cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, in pure culture there was a linear relationship between electrical signal and <I>C. sakazakii</I> levels over the range 2.0 × 10<SUP>2</SUP>–2.0 × 10<SUP>7</SUP> cfu/mL (R<SUP>2</SUP> = 0.999), with a detection limit of 2.0 × 10<SUP>1</SUP> cfu/mL. The total analytical time was 15 min per sample. The <I>C. sakazakii</I> electrochemical immunosensing assay was able to successfully detect 2.0 × 10<SUP>1</SUP> cfu/mL of <I>C. sakazakii</I> in artificially contaminated powdered infant formula without any enrichment or pre-enrichment steps. Furthermore, the recovery rates of the <I>C. sakazakii</I> electrochemical immunosensing assay following spiking of powdered infant formula with different concentrations of <I>C. sakazakii</I> (cfu/mL) were 82.58% at 2.0 × 10<SUP>1</SUP> cfu/mL, 84.86% at 2.0 × 10<SUP>2</SUP> cfu/mL, and 95.40% at 2.0 × 10<SUP>3</SUP> cfu/mL. The <I>C. sakazakii</I> electrochemical immunosensing assay had good selectivity, reproducibility, and reactivity compared with other <I>Cronobacter</I> spp. and/or pathogens belonging to other genera, indicating its significant potential in the clinical diagnosis of <I>C. sakazakii</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Development of a GO/Au nanocomposite-based electrochemical immunosensing for <I>Cronobacter sakazakii</I> detection. </LI> <LI> The developed assay detected 2.0 × 10<SUP>1</SUP> cfu/mL of <I>C. sakazakii</I> in pure culture as well as in infant formula powder. </LI> <LI> Developed assay required a total analytical performance time of 15 min per sample. </LI> <LI> The assay facilitated sensitive, efficient, and rapid detection of <I>C. sakazakii</I> without any interfering factor. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Interaction of VOCs with pyrene tetratopic ligands layered on ZnO nanorods under visible light

Sivalingam, Y.,Elumalai, P.,Yuvaraj, S.V.J.,Magna, G.,Sowmya, V.J.,Paolesse, R.,Chi, K.W.,Kawazoe, Y.,Di Natale, C. Elsevier Sequoia 2016 Journal of photochemistry and photobiology Chemist Vol.324 No.-

<P>In this work, the relationship between photosensitivity and chemical sensitivity of zinc oxide (ZnO) nanorods coated with pyrene based tetratopic ligands (PTL) is investigated under visible light. The electrical resistance of ZnO-PTL is affected by adsorption of different volatile organic compounds (VOCs) such as ethanol, n-hexane, trimethylamine, and triethylamine. The illumination strongly affects the response to the VOCs. To elucidate the interaction mechanism between PTL and VOCs, the experimental studies have been complemented by first principles calculations. Both experimental and computational results have shown that the amines are bound to PTL with higher affinity followed by ethanol (alcohol) and n-hexane (alkane). Our results have proved that the COOH functional group at the peripheral site of PTL is not only used for anchoring the molecule onto the ZnO, but it is also the main adsorption site for the VOCs, in particular for amines. In practice, the photo-optical properties of pyrene molecules are complemented by the high affinity of COOH group for amines in order to achieve a photo-activated sensor. The complementary use of optical dyes and chemical ligands can provide an innovative methodology for chemical sensors design. (C) 2016 Elsevier B.V. All rights reserved.</P>

Study of mechanical properties of self-adhesive mortars with sugar cane bambasse ash and silica activator

P. Sudha,S. Ramesh,R. Jagadeesan,K. Yuvaraj 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.1

This research is justified by the need to find other solutions to reduce the consumption of fine aggregate, replacing it with wasteor by-products from other industrial sectors. Among these residues, sugarcane bagasse ash (SBA) is highlighted. SBA is aresidue generated during the sugar and alcohol production process, studies carried out by several authors have identified thatthis is a material that has physical characteristics close to those of fine aggregates and in some cases has pozzolan potential. This work intends to evaluate the properties of resistance to segregation and exudation, in addition to the ability to meet theminimum density requirements of mortars containing silica fume as fine material and sugarcane bagasse ash as fine aggregate. Also, the mechanical properties of self-compacting mortars will be analyzed.

Triazine-based 2D covalent organic framework-derived nitrogen-doped porous carbon for supercapacitor electrode

Vargheese Stella,Dinesh Muthu,Kavya K. V.,Pattappan Dhanaprabhu,Rajendra Kumar Ramasamy Thangavelu,Haldorai Yuvaraj 한국탄소학회 2021 Carbon Letters Vol.31 No.5

Doped porous carbon materials have attracted great interest owing to their excellent electrochemical performance toward energy storage applications. In this report, we described the synthesis of nitrogen-doped porous carbon (N-PC) via carbonization of a triazine-based covalent organic framework (COF) synthesized by Friedel–Crafts reaction. The as-synthesized COF and N-PC were confrmed by X-ray difraction. The N-PC exhibited many merits including high surface area (711 m2 g−1), porosity, uniform pore size, and surface wettability due to the heteroatom-containing lone pair of electron. The N-PC showed a high specifc capacitance of 112 F g−1 at a current density of 1.0 A g−1 and excellent cyclic stability with 10.6% capacitance loss after 5000 cycles at a current density of 2.0 A g−1. These results revealed that the COF materials are desirable for future research on energy storage devices.