Metallurgical Characterization and Mechanical Properties of Solid–Liquid Compound Casting of Aluminum Alloy: Steel Bimetallic Materials

Pavan Kalyan Kota,Govindaraju Myilsamy,Vaira Vignesh Ramalingam 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Integration of two metallurgically distinct materials (bimetallic) is an inevitable advancement in the automotive andmarine field. In this context, this study investigates the fabrication, characterization, and properties of solid–liquid compoundcast aluminum alloy AA5052 and ferrous alloy (mild steel and galvanized iron) based bimetallic materials. Microstructuralevolution, microhardness, and tensile strength of the developed bimetallic material are investigated. The results show thatthe formation of cracks at the interface in AA5052/Mild Steel caused the joint failure in the course of preliminary testing. InAA5052/Galvanized Iron, the growth of intermetallics at the oxide-free steel surface results in a shear strength of 19.9 MPa. XRD analysis attests to the presence of brittle intermetallics and Al bond at the interface of AA5052/Galvanized Iron bimetallicmaterial, which in turn confirms the development of a metallurgical.

n-th power signed graphs

Siva Kota Reddy,Vijay,Lokesha 장전수학회 2009 Proceedings of the Jangjeon mathematical society Vol.12 No.3

A signed graph (marked graph) is an ordered pair S = (G, σ) (S = (G, μ)), where G = (V,E) is a graph called the underlying graph of S and σ : E → {+, −} (μ : V → {+, −}) is a function. The n-th power graph of a graph G = (V,E) is a graph Gn = (V,E'), with same vertex set as G, and has two vertices u and v are adjacent if their distance in G is n or less. Analogously, one can define the nth power signed graph of a signed graph S = (G, σ). Consider the marking μ on vertices of S defined as follows: each vertex v ∈ V , μ(v) is the product of the signs on the edges incident at v. The nth power signed graph of S is a signed graph Sn = (Gn, σ') where Gn is the underlying graph of Sn, where for any edge e = uv 2 Gn, 0(uv) = μ(u)μ(v). It is shown that for any signed graph S, its nth power signed graph Sn is balanced. We then give structural characterization of n-th power signed graphs. Two signed graphs S1 and S2 are switiching equivalent written S1 ~ S2, whenever there exists a marking μ of S1 such that the signed graph Sμ(S1) obtained by changing the sign of every edge of S1 to its opposite whenever its end vertices are of opposite signs, is isomorphic to S2. Further, we present solutions of some signed graph switching equations involving the line signed graph, complement and n-th power signed graph operations. One such equation (L(S))n ~ S generalizes a result of P. Siva Kota Reddy and M. S. Subramanya (L(S) ~ S) [11].

Feasibility Studies of a Vibration Wire Monitor and a Halo Scraper in the J-PARC L3BT

Kota Okabe,Kazami Yamamoto,Masahiro Yoshimoto,Michikazu Kinsho 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7

In the Japan Proton Accelerator Research Complex (J-PARC) 3-GeV rapid cycle synchrotron(RCS), transverse beam halo diagnostics and scraping are required to increase the output beampower. Wire scanners and halo scrapers were used to measure the projected beam distributions todetermine the extent of beam halo formation at the linac 3-GeV beam transport line (L3BT). Inorder to determine more details of halo formation, we installed a vibration wire monitor (VWM) inthe L3BT for the beam halo measurement. The high sensitivity of the VWM makes it a prospectivetool for investigating the beam halo and weak beam scanning. Also, we developed a new verticalscraper system with a thin carbon foil to collimate the beam halo in the L3BT. In this paper, wewill report a preliminary result for the beam-halo measurement by using a VWM and a halo scraperat the L3BT, and we will discuss the potential of the VWM for beam-halo diagnostics.

Holocene centuries scale climate changes in the Indian Sector of the Antarctic Ocean

Kota Katsuki,Minoru Ikehara,Yusuke Yokoyama,Masako Yamane,Yoshifumi Nogi,김부근 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

An Application of Artificial Intelligence to Diagnostic Imaging of Spine Disease: Estimating Spinal Alignment From Moiré Images

Kota Watanabe,Yoshimitsu Aoki,Morio Matsumoto 대한척추신경외과학회 2019 Neurospine Vol.16 No.4

The use of artificial intelligence (AI) as a tool supporting the diagnosis and treatment of spinal diseases is eagerly anticipated. In the field of diagnostic imaging, the possible application of AI includes diagnostic support for diseases requiring highly specialized expertise, such as trauma in children, scoliosis, symptomatic diseases, and spinal cord tumors. Moiré topography, which describes the 3-dimensional surface of the trunk with band patterns, has been used to screen students for scoliosis, but the interpretation of the band patterns can be ambiguous. Thus, we created a scoliosis screening system that estimates spinal alignment, the Cobb angle, and vertebral rotation from moiré images. In our system, a convolutional neural network (CNN) estimates the positions of 12 thoracic and 5 lumbar vertebrae, 17 spinous processes, and the vertebral rotation angle of each vertebra. We used this information to estimate the Cobb angle. The mean absolute error (MAE) of the estimated vertebral positions was 3.6 pixels (~5.4 mm) per person. T1 and L5 had smaller MAEs than the other levels. The MAE per person between the Cobb angle measured by doctors and the estimated Cobb angle was 3.42°. The MAE was 4.38° in normal spines, 3.13° in spines with a slight deformity, and 2.74° in spines with a mild to severe deformity. The MAE of the angle of vertebral rotation was 2.9°±1.4°, and was smaller when the deformity was milder. The proposed method of estimating the Cobb angle and AVR from moiré images using a CNN is expected to enhance the accuracy of scoliosis screening.

A diverse assemblage of moths feeding on aphid honeydew

Kota Sakagami,Shinji Sugiura 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

Adult butterflies and moths (Lepidoptera) use their proboscises to feed on flower nectar and other types of liquidfood. Aphids frequently secrete honeydew from their anuses, attracting various types of insects, such as ants. Adult lepidopterans are also known to feed on aphid honeydew. However, very few studies have clarified thespecies composition and morphology of moths feeding on aphid honeydew. In late June 2017, we found nocturnalmoths sipping honeydew secreted by Shivaphis celti and Sitobion cornifoliae (Hemiptera: Aphididae) onleaves of Celtis sinensis (Cannabaceae) and Cornus kousa (Cornaceae), respectively, at the edge of a secondaryforest in central Japan. The moths were observed to uncoil their proboscises and feed on honeydew on theleaves. No moths were observed to feed on honeydew directly from aphids. Nocturnal moths of 60 species (11families) and 16 species (7 families) were collected from honeydew on Ce. sinensis and Co. kousa leaves, respectively. Eleven moth species were shared between the two types of honeydew. The most abundant species,Oncocera semirubella (Lepidoptera: Pyralidae), accounted for 44.7% of all individuals. The sex ratio of O. semirubellawas female biased. Of the 65 moth species collected on aphid honeydew, 52.3% (34 species) have beenpreviously reported to visit flowers. Moths visiting honeydew had relatively short proboscises and small bodysize. These results suggest that aphid honeydew is an important, accessible food resource for moths of small size.

Improved plastid transformation efficiency in Scoparia dulcis L.

Kota, Srinivas,Hao, Qiang,Narra, Muralikrishna,Anumula, Vaishnavi,Rao, A.V,Hu, Zanmin,Abbagani, Sadanandam The Korean Society of Plant Biotechnology 2019 식물생명공학회지 Vol.46 No.4

The high expression level of industrial and metabolically important proteins in plants can be achieved by plastid transformation. The CaIA vector, a Capsicum-specific vector harboring aadA (spectinomycin resistance), is a selectable marker controlled by the PsbA promoter, and the terminator is flanked by the trnA and trnI regions of the inverted repeat (IR) region of the plastid. The CaIA vector can introduce foreign genes into the IR region of the plastid genome. The biolistic method was used for chloroplast transformation in Scoparia dulcis with leaf explants followed by antibiotic selection on regeneration medium. Transplastomes were successfully screened, and the transformation efficiency of 3 transgenic lines from 25 bombarded leaf explants was determined. Transplastomic lines were evaluated by PCR and Southern blotting for the confirmation of aadA insertion and its integration into the chloroplast genome. Seeds collected from transplastomes were analyzed on spectinomycin medium with wild types to determine genetic stability. The increased chloroplast transformation efficiency (3 transplastomic lines from 25 bombarded explants) would be useful for expressing therapeutically and industrially important genes in Scoparia dulcis L.

Ice-templated three dimensional nitrogen doped graphene for enhanced supercapacitor performance

Kota, M.,Yu, X.,Yeon, S.H.,Cheong, H.W.,Park, H.S. Elsevier Sequoia 2016 Journal of Power Sources Vol.303 No.-

The three-dimensional (3D), nitrogen doped reduced graphene oxide (N-RGO) monoliths have been synthesized using graphene oxide and melamine through an ice-templated assembly. The self-assembled monoliths are accompanied with the considerable reduction of graphene oxide after annealing and specific surface area of 190 m<SUP>2</SUP> g<SUP>-1</SUP>. The blue shift of approximately 22 cm<SUP>-1</SUP> and 4 cm<SUP>-1</SUP> in D and G bands for N-RGO is notified in Raman analysis, confirming the incorporation of nitrogen onto the graphene sheet. In addition, an extra peak at 1251 cm<SUP>-1</SUP> appears possibly due to the stretching vibration of C-N bonds. The detailed doping configurations analyzed by x-ray photoemission spectroscopy indicate the nitrogen content of around 6.2 at% in the N-RGO with predominant pyridinic N-type configuration. The specific capacitance is enhanced up to 217 F g<SUP>-1</SUP> at a scan rate of 5 mV s<SUP>-1</SUP>, which is approximately three times higher than that of the pristine 3D RGO owing to the pseudocapacitive behavior of N-RGO. The high electronic conductivity of the N-RGO electrode with low charge transfer resistance as confirmed by electrochemical impedance spectroscopy is associated with good rate capability. Furthermore, the N-RGO sample exhibits an excellent cyclic stability with no decay in capacitance even after 5000 cycles at scan rate of 100 mV s<SUP>-1</SUP>.

Improving energy density of supercapacitors using heteroatom-incorporated three-dimensional macro-porous graphene electrodes and organic electrolytes

Kota, Manikantan,Jana, Milan,Park, Ho Seok Elsevier 2018 Journal of Power Sources Vol.399 No.-

<P><B>Abstract</B></P> <P>The synthesis of nitrogen- and sulfur-doped three-dimensional (3D) graphene architectures further treated by steam activation to increase surface area is reported in this study. Tetraethylammonium tetrafluoroborate (TEABF<SUB>4</SUB>) in propylene carbonate as an organic electrolyte is used to enlarge the voltage range of a supercapacitor (SC) for high energy density. The 3D nitrogen- and sulfur-doped, steam activated, reduced graphene oxides (N-SRGO and S-SRGO) contained 7.84% and 6.93% of N and S heteroatoms and feature 497 m<SUP>2</SUP> g<SUP>−1</SUP> and 525 m<SUP>2</SUP> g<SUP>−1</SUP> of surface area due to hieratical porosity of the substance. As shown in the galvanic charge/discharge curves, a range of 0–2.5 V in the 3D N-SRGO architectures showed the highest capacitance of 23.1 F g<SUP>−1</SUP>, delivering maximum energy and power densities of up to 20 W h kg<SUP>−1</SUP> and 6190 W kg<SUP>−1</SUP>. The rate capability and cycle stability over 5000 cycles were evaluated to be 63% and 68%, respectively, for N-SRGO. This study provides a systematic way to improve energy density of SCs by combining heteroatom-doped 3D graphene architecture with an organic TEABF<SUB>4</SUB>/PC electrolyte.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The 3D hieratically porous doped graphene architecture is constructed. </LI> <LI> Heteroatoms are uniformly distributed onto the 3D graphene surface. </LI> <LI> A full cell supercapacitor is fabricated using organic electrolytes. </LI> <LI> Energy density of cell is enhanced improving specific capacitance and potential window. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

ALIAS FREE SUBBAND ADAPTIVE FILTER BASED ON RECURSIVE LEAST SQUARES ALGORITHM FOR FINITE WORD-LENGTH IMPLEMENTATION

Kota ENDO,Kiyoshi NISHIKAWA,Hitoshi KIYA 대한전자공학회 2006 ITC-CSCC :International Technical Conference on Ci Vol.2006 No.3