Weldability Study on SS 304B4 Joined using Boron Containing Austenitic Stainless Steel Consumable

M. Divya,S. K. Albert 대한용접접합학회 2018 대한용접·접합학회지 Vol.36 No.6

304B4 stainless steel contains ~1.2 wt.% of boron intentionally added for neutron shielding purposes in nuclear power plants and nuclear waste storage applications. Weldabilty of 304B4 stainless steel is generally considered to be poor because boron is almost insoluble in austenite phase and has a tendency to segregate in the liquid phase during solidification. This results in formation of different types of borides in the eutectic which melts at low temperature and makes the steel susceptible to cracking. Among the welding consumables specified in standards and codes, E309 consumable is the one generally recommended for this steel, but electrodes with controlled addition of boron (E308BRN) is also available. A systematic study on solidification cracking susceptibility of 304B4 stainless steel weld joint prepared using E308BRN containing ~1 wt.% B has been carried out. Further, mechanical properties of weld joints made with this electrode are compared with that made from E309 electrode. Results show that E308BRN electrode can be chosen for applications involving low restraint forces to produce crack free joints. Mechanical properties of the joints made with both E308BRN and E309 are poor when compared to the base metal. This is attributed to continuous network of eutectic borides present in the interdendritic regions of fusion zone and partially melted zones of the weld joints.

OPTIMAL CONTROL AND HOPF BIFURCATION ANALYSIS OF DELAY DEPENDENT HIV PROTEASE INHIBITOR MODEL

M. Divya 경남대학교 수학교육과 2020 Nonlinear Functional Analysis and Applications Vol.25 No.3

In this article, HIV protease inhibitor model with three intracellular delays is considered and the stability analysis for the case of τ̄ = 0 where, τ̄ = τ + τ_2 and τ_1 ≠ 0 for the same model is examined. τ_1, the delay corresponding to the loss of target cells is viewed as a bifurcation parameter, a limit cycle bifurcation about the infected steady state is scrutinized. Further, a mathematical model of HIV protease inhibitor model using control terms is presented and analysed mathematically.

An Applicative Approach for Collecting and Fortifying History of Data in Cloud Environment

Divya Vadlamudi,M. Krishna Chaitanya,T. Srikanth,V. Bala Venu,U.Joseph,Tai-hoon Kim 보안공학연구지원센터 2015 International Journal of Software Engineering and Vol.9 No.5

Today cloud computing has been the buzzword among many communities. Many users are using the cloud to ensure cost effectiveness towards their hardware resources. As cloud may seem tempting there are many security issues relating to the cloud. One the issue is the activities performed on the data, which are monitored by logs. These logs are used as evidence to the forensic investigators. But due to the emerging technologies the hackers are able to modify the log data. When the hackers modify the data, it is a painful task for the forensic investigators to rebuild the evidence. So to address this issue we are developing a mechanism to generate the log files, ensure security to log files and making the log files interoperable to the Cloud Service Provider (CSP).

Carbon based manganese oxide (MnO2, MnO2/MWCNT and MnO2/rGO) composite electrodes for high-stability Li-ion batteries

Rosaiah Pitcheri,Divya Ponnusamy,Sambasivam Sangaraju,Tighezza Ammar M.,Kalaivani V.,Muthukrishnaraj A.,Ayyar Manikandan,Niyitanga Theophile,Kim Haekyoung 한국탄소학회 2024 Carbon Letters Vol.34 No.1

Synthesis of extremely competent materials is of great interest in addressing the energy storage concerns. Manganese oxide nanowires (MnO2 NWs) are prepared in situ with multiwall carbon nanotubes (MWCNT) and graphene oxide (GO) using a simple and effective hydrothermal method. Powder XRD, Raman and XPS analysis are utilized to examine the structural characteristics and chemical state of composites. The initial specific discharge capacity of pure MnO2 NWs, MnO2 NWs/MWCNT and MnO2 NWs/rGO composites are 1225, 1589 and 1685 mAh/g, respectively. The MnO2 NWs/MWCNT and MnO2 NWs/rGO composites showed stable behavior with a specific capacity of 957 and 1108 mAh/g, respectively, after 60 cycles. Moreover, MnO2 NWs/rGO composite sustained a specific capacity of 784 mAh/g, even after 250 cycles at a current density of 1 A/g showing outstanding cycling stability.

Development of Symmetrical Fault Detection During Power Swing Based on Entropy

Devi R.,Kirthika A.,Divya Priyadharshini M.,Ladha Akash,Anju A.,Rajesh Kumar T.,Ganesh Prabhu S.,Varghese Lijo Jacob,Santhosh P. 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3

This paper proposes the new technique for detecting symmetrical faults occurred during power swing. The proposed technique is simulated for the protection of two machine system, distribution system with distributed generation and WSCC 9-bus system in Matlab. Symmetrical fault detection during power swing is a critical issue. Hence, in this paper, modifi ed weighted wavelet packet entropy technique is proposed to detect symmetrical fault during power swing. This entropy criterion is applied to wavelet packet coeffi cients to enhance the energy of fault signals and to reduce the vector size of the wavelet packet transform coeffi cients. This technique provides better results irrespective of various fault locations, fault inception angle and power swing frequencies. This technique is compared with conventional scheme and the results are tabulated. Moreover, this technique is also able to detect asymmetrical faults with high impedance during power swing. Mathematical derivation support system performance through simulation.

Positioning errors and quality assessment in panoramic radiography

Manu Dhillon,Srinivasa M Raju,Sankalp Verma,Divya tomar,Raviprakash S Mohan,Manisha Lakhanpal,Bhuvana Krishnamoorthy 대한구강악안면방사선학회 2012 Imaging Science in Dentistry Vol.42 No.4

Purpose: This study was performed to determine the relative frequency of positioning errors, to identify those errors directly responsible for diagnostically inadequate images, and to assess the quality of panoramic radiographs in a sample of records collected from a dental college. Materials and Methods: This study consisted of 1,782 panoramic radiographs obtained from the Department of Oral and Maxillofacial Radiology. The positioning errors of the radiographs were assessed and categorized into nine groups: the chin tipped high, chin tipped low, a slumped position, the patient positioned forward, the patient positioned backward, failure to position the tongue against the palate, patient movement during exposure, the head tilted, and the head turned to one side. The quality of the radiographs was further judged as being ‘excellent’, ‘diagnostically acceptable’, or ‘unacceptable’. Results: Out of 1,782 radiographs, 196 (11%) were error free and 1,586 (89%) were present with positioning errors. The most common error observed was the failure to position the tongue against the palate (55.7%) and the least commonly experienced error was patient movement during exposure (1.6%). Only 11% of the radiographs were excellent, 64.1% were diagnostically acceptable, and 24.9% were unacceptable. Conclusion: The positioning errors found on panoramic radiographs were relatively common in our study. The quality of panoramic radiographs could be improved by careful attention to patient positioning.

Influence of traditional medicines on the activity of keratinocytes in wound healing: an in-vitro study

Sushma R. Kotian,Kumar M. R. Bhat,Divya Padma,K. Sreedhara R. Pai 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.3

Natural medicinal systems such as Ayurveda and folk medicine has remedies for wound management. However, the exact cellular and extracellular mechanisms involved in the healing process and its influence on keratinocytes is less discussed. Therefore, the present study was designed to evaluate the effect of certain natural wound healing medicines on the biology of the keratinocytes/HaCaT cells. Test materials such as honey (H), ghee (G), aqueous extracts of roots of Glycyrrhiza glabra (GG) and leaves of Nerium indicum (NI) were considered. The HaCaT cells were treated with the test materials singly and in combinations (H+G, all combined [Tot]) for a specific period (24, 48, and 72 hours). The cells were then subjected to cytotoxicity/proliferation and migration/scratch assays. All the test materials, except NI, were non-cytotoxic and showed increased cell proliferation at variable concentrations. Significant observations were made in the groups treated with honey (100 µg/ml at 48 hours, P<0.05; 1,000 µg/ml at 72 hours, P<0.05), GG (all concentrations at 48 hours, P<0.05; 750 µg/ml at 72 hours, P<0.05), H+G (250 µg/ml at 24 hours, P<0.001; 500 µg/ml at 48 and 72 hours, P<0.05), and Tot (50 µg/ml at 24, 48 and 72 hours, P<0.01). In the in-vitro wound healing assay, all the treated groups showed significant migration and narrowing of the scratch area by 24 and 48 hours (P<0.001) compared to control. The results obtained from the present study signifies the positive influence of these natural wound healing compounds on keratinocytes/HaCaT cells.

Facile exfoliation and physicochemical characterization of biomass-based cellulose derived from Lantana aculeata leaves for sustainable environment

S. Gokulkumar,Indran Suyambulingam,Divya Divakaran,G. Suganya Priyadharshini,M. Aravindh,Jenish Iyyadurai,M. Sanju Edwards,Suchart Siengchin 한국고분자학회 2023 Macromolecular Research Vol.31 No.12

Researchers are focusing their efforts on developing high-performance bio-based composites due to increased interest in the production of natural fiber-based polymer composites utilizing novel cellulosic fillers. The primary goal of this study is to comprehend physicochemical and morphological characteristics, crystallinity, and thermal behavior of Lantana aculeata leaf cellulose (LALC) fillers. The extracted cellulose has some unique properties, such as excellent mechanical properties, lower density, bio-compatibility, heat resistance, and processability. Using X-ray diffraction, crystallinity index and size of Lantana aculeata leaf cellulose were calculated to be 73.7 and 7.42 nm, respectively. Furthermore, the morphology of the extracted LALC filler was examined using Scanning Electron Microscopy (SEM) and ImageJ software, and its average size was determined to be 69.21 nm. In addition, Fourier-transform infrared spectroscopy (FTIR) revealed that the extracted LALC contained no other non-cellulosic components due to alkali treatment, as they isolate cellulose and minimize the presence of non-cellulosic components. Furthermore, atomic force microscopy (AFM) revealed that the surface roughness of the cellulose is less than 4.630 nm, paving the way for an agricultural residue to be transformed into a desirable cellulosic filler material for developing polymeric composites. It can also withstand temperatures of maximum up to 247.23 °C, making it a viable substitute for more traditional sources. It can be used in a variety of polymer composite applications, including packaging materials, automotive parts, and building materials.

Positioning errors and quality assessment in panoramic radiography

Dhillon, Manu,Raju, Srinivasa M.,Verma, Sankalp,Tomar, Divya,Mohan, Raviprakash S.,Lakhanpal, Manisha,Krishnamoorthy, Bhuvana Korean Academy of Oral and Maxillofacial Radiology 2012 Imaging Science in Dentistry Vol.42 No.4

Purpose: This study was performed to determine the relative frequency of positioning errors, to identify those errors directly responsible for diagnostically inadequate images, and to assess the quality of panoramic radiographs in a sample of records collected from a dental college. Materials and Methods: This study consisted of 1,782 panoramic radiographs obtained from the Department of Oral and Maxillofacial Radiology. The positioning errors of the radiographs were assessed and categorized into nine groups: the chin tipped high, chin tipped low, a slumped position, the patient positioned forward, the patient positioned backward, failure to position the tongue against the palate, patient movement during exposure, the head tilted, and the head turned to one side. The quality of the radiographs was further judged as being 'excellent', 'diagnostically acceptable', or 'unacceptable'. Results: Out of 1,782 radiographs, 196 (11%) were error free and 1,586 (89%) were present with positioning errors. The most common error observed was the failure to position the tongue against the palate (55.7%) and the least commonly experienced error was patient movement during exposure (1.6%). Only 11% of the radiographs were excellent, 64.1% were diagnostically acceptable, and 24.9% were unacceptable. Conclusion: The positioning errors found on panoramic radiographs were relatively common in our study. The quality of panoramic radiographs could be improved by careful attention to patient positioning.

Mesenchymal Stem Cells of Different Origin-Seeded Bioceramic Construct in Regeneration of Bone Defect in Rabbit

Swapan Kumar Maiti,M. U. Shivakumar,Divya Mohan,Naveen Kumar,Karam Pal Singh 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.4

BACKGROUND: Stem cell is currently playing a major role in the treatment of number of incurable diseases via transplantation therapy. The objective of this study was to determine the osteogenic potential of allogenic and xenogenic bone-derived MSC seeded on a hydroxyapatite (HA/TCP) bioceramic construct in critical size bone defect (CSD) in rabbits. METHODS: A 15 mm long radial osteotomy was performed unilaterally in thirty-six rabbits divided equally in six groups. Bone defects were filled with bioscaffold seeded with autologous, allogenic, ovine, canine BMSCs and cell free bioscaffold block in groups A, B, C, D and E respectively. An empty defect served as the control group. RESULTS: The radiological, histological and SEM observations depicted better and early signs of new bone formation and bridging bone/implant interfaces in the animals of group A followed by B. Both xenogenous MSC-HA/TCP construct also accelerated the healing of critical sized bone defect. There was no sign of any inflammatory reaction in the xenogenic composite scaffold group of animals confirmed their well acceptance by the host body. CONCLUSION: In vivo experiments in rabbit CSD model confirmed that autogenous, allogenous and xenogenous BMSC seeded on bioscaffold promoted faster healing of critical size defects. Hence, we may suggest that BMSCs are suitable for bone formation in fracture healing and non-union.