Reactive Behavior of Ferrihydrite and Aluminic Ferrihydrite Toward the Adsorption of Arsenate

Mohapatra, Debasish,Mishra, Debaraj,Chaudhury, G. Roy,Das, R.P.,Park, Kyung-Ho 한국암반공학회 2006 Geosystem engineering Vol.9 No.2

The adsorption of arsenate (As(V)) on "ferrihydrite" prepared by two different methods; "aluminic ferrihydrite" (Fe(III)/ AI(III) molar ratio 1:1) and the stability of As(V) bearing materials were investigated. The parameters optimized for adsorption were pH, contact time, adsorbent and As(V) concentration. For leaching study four different leaching reagents (10mg C/L dissolved organic matter, 0.1M phosphate, 0.1M citrate and 0.1M oxalate) were used. The kinetics of arsenic adsorption on both type of ferrihydrites were similar with an equilibrium time of 1h; whereas, in case of aluminic ferrihydrite the equilibrium time was 3h. For aluminic ferrihydrite, maximum adsorption was found at pH 6.0. Whereas, for ferrihydrites pH 7.0 was found to be the best for As(V) adsorption. The highest As(V) adsorption capacity was shown by aluminic ferrihydrite (21.8 mg/g), followed by ferrihydrite prepared by emulsion method and ferrihydrite prepared by ordinary method (14.9 and 9.8 mg/g, respectively). In case of As(V) extraction from the loaded materials, the pH had a significant effect. In all cases, except citrate for aluminic ferrihydrite, extraction decreased with increasing pH in the range 5.0-8.0. For oxalate the iron extraction and for citrate the aluminium extraction followed the same trend as that for arsenic as a function of pH, suggesting that dissolution of these metals and consequent release of the adsorbed arsenic is one of the main mechanisms for arsenic extraction. However, for phosphate and DOM, the As(V) extraction mechanism was competition between arsenic and those anions for adsorption sites.

Secure Communications for the Two-User Broadcast Channel With Random Traffic

Mohapatra, Parthajit,Pappas, Nikolaos,Lee, Jemin,Quek, Tony Q. S.,Angelakis, Vangelis IEEE 2018 IEEE transactions on information forensics and sec Vol.13 No.9

<P>In this paper, we study the stability region of the two-user broadcast channel (BC) with bursty data arrivals and security constraints. It is assumed that one of the receivers has a secrecy constraint, i.e., its packets need to be kept secret from the other receiver, which is defined based on signal to interference noise ratio. The receiver with secrecy constraint has full-duplex capability to send a jamming signal for improving its service rate. The stability region of the two-user BC with secrecy constraint is characterized for the general decoding case. Then, assuming two different decoding schemes, the respective stability regions are derived. The full-duplex operation of receiver results in self-interference, and the effect of imperfect self-interference cancelation on the stability region is also investigated. The stability region of the BC with a secrecy constraint, where the receivers do not have full duplex capability can be obtained as a special case of the results derived in this paper. In addition, the paper considers the problem of maximizing the saturated throughput of the queue for which there is no secrecy constraint under minimum service guarantees for the other queue. The results provide new insights on the effect of the secrecy constraint on the stability region of the BC. It is found that the stability region with secrecy constraint is sensitive to the degree of self-interference cancelation.</P>

From In Vitro to Perioperative Vascular Tissue Engineering: Shortening Production Time by Traceable Textile-Reinforcement

Mohapatra Saurav Ranjan,Rama Elena,Melcher Christoph,Call Tobias,Al Enezy-Ulbrich Miriam Aischa,Pich Andrij,Apel Christian,Kiessling Fabian,Jockenhoevel Stefan 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.6

BACKGROUND: The production of tissue-engineered vascular graft (TEVG) usually involves a prolonged bioreactor cultivation period of up to several weeks to achieve maturation of extracellular matrix and sufficient mechanical strength. Therefore, we aimed to substantially shorten this conditioning time by combining a TEVG textile scaffold with a recently developed copolymer reinforced fibrin gel as a cell carrier. We further implemented our grafts with magnetic resonance imaging (MRI) contrast agents to allow the in-vitro monitoring of the TEVG’s remodeling process. METHODS: Biodegradable polylactic-co-glycolic acid (PLGA) was electrospun onto a non-degradable polyvinylidene fluoride scaffold and molded along with copolymer-reinforced fibrin hydrogel and human arterial cells. Mechanical tests on the TEVGs were performed both instantly after molding and 4 days of bioreactor conditioning. The non-invasive in vitro monitoring of the PLGA degradation and the novel imaging of fluorinated thermoplastic polyurethane (19F-TPU) were performed using 7T MRI. RESULTS: After 4 days of close loop bioreactor conditioning, 617 ± 85 mmHg of burst pressure was achieved, and advanced maturation of extracellular matrix (ECM) was observed by immunohistology, especially in regards to collagen and smooth muscle actin. The suture retention strength (2.24 ± 0.3 N) and axial tensile strength (2.45 ± 0.58 MPa) of the TEVGs achieved higher values than the native arteries used as control. The contrast agents labeling of the TEVGs allowed the monitorability of the PLGA degradation and enabled the visibility of the non-degradable textile component. CONCLUSION: Here, we present a concept for a novel textile-reinforced TEVG, which is successfully produced in 4 days of bioreactor conditioning, characterized by increased ECM maturation and sufficient mechanical strength. Additionally, the combination of our approach with non-invasive imaging provides further insights into TEVG’s clinical application.

Some Device Design Considerations to Enhance the Performance of DG-MOSFETs

Mohapatra, S.K.,Pradhan, K.P.,Sahu, P.K. The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.6

When subjected to a change in dimensions, the device performance decreases. Multi-gate SOI devices, viz. the Double Gate MOSFET (DG-MOSFET), are expected to make inroads into integrated circuit applications previously dominated exclusively by planar MOSFETs. The primary focus of attention is how channel engineering (i.e. Graded Channel (GC)) and gate engineering (i.e. Dual Insulator (DI)) as gate oxide) creates an effect on the device performance, specifically, leakage current ($I_{off}$), on current ($I_{on}$), and DIBL. This study examines the performance of the devices, by virtue of a simulation analysis, in conjunction with N-channel DG-MOSFETs. The important parameters for improvement in circuit speed and power consumption are discussed. From the analysis, DG-DI MOSFET is the most suitable candidate for high speed switching application, simultaneously providing better performance as an amplifier.

Synthesis and Characterization of UO₂(VI), Th(IV), ZrO(IV) and VO(IV) Complexes with Schiff-Base Octaazamacrocyclic Ligands

Mohapatra, Ranjan Kumar,Dash, Dhruba Charan Korean Chemical Society 2010 대한화학회지 Vol.54 No.4

[M(L/L')$(NO_3)_n$].$mH_2O$ 및 [VO(L/L')($SO_4)$].$2H_2O$ (여기서 L/L'는 Schiff 염기로 thiocarbohydrazide (TCH), benzilmonohydrazone (BMH)/diacetylmonohydrazone (DMH) 및 carbon disulphide에서 유도된 "3,4,10,11-tetraphenyl/tetramethyl-1,2,5,6,8,9,12,13-octaazacyclotetradeca-2,4,9,11-tetraene-7,14-dithione")의 분자식을 갖는 일련의 거대고리 착물을 (M = $UO_2$(VI), Th(IV) and ZrO(IV), n = 2, 4, m = 2, 3)을 금속이온 주형법으로 합성하였다. 이들 착물의 특성을 원소분석, 열분석, 몰 전기전도도, 자기모멘트 그리고 전자, 적외선 및 $^1H$-NMR로 조사하였다. 바나딜 착물의 경우 ESR 및 순환 전압전류법을 사용하였다. 그 결과, VO(IV) 이온은 5배위의 상자기성 착물을 이루며, $UO_2$(VI) 및 ZrO(IV)는 6배위 그리고 Th(IV)는 8배위를 가지나 공통적으로 위의 조성을 갖는 반자기성임을 알았다. A series of macrocyclic complexes of the type [M(L/L')$(NO_3)_n$].$mH_2O$ and [VO(L/L')($SO_4$)].$2H_2O$, where L/L' is a Schiff base "3,4,10,11-tetraphenyl/tetramethyl-1,2,5,6,8,9,12,13-octaaza cyclotetradeca-2,4,9,11-tetraene-7,14-dithione" derived from thiocarbohydrazide (TCH), benzilmonohydrazone (BMH)/diacetylmonohydrazone (DMH) and carbon disulphide, M = $UO_2$ (VI), Th(IV) and ZrO(IV), n = 2, 4, m = 2, 3, have been synthesized via metal ion template methods. The complexes are characterized on the basis of elemental analysis, thermal analysis, molar conductivity, magnetic moment, electronic, infrared and $^1H$-NMR spectral studies. The ESR and cyclic voltammetry studies of the vanadyl complexes have been carried out. The results indicate that the VO(IV) ion is penta-coordinated yielding paramagnetic complexes; $UO_2$(VI) and ZrO(IV) ions are hexacoordinated where as Th(IV) ion is octa-coordinated yielding diamagnetic complexes of above composition.

Removal of Arsenic(V) from Aqueous Solutions by Using Natural Minerals

Mohapatra Debasish,Mishra Debaraj,Chaudhury G. Roy,Das R.P.,Park, Kyung-Ho The Korean Institute of Resources Recycling 2006 資源 리싸이클링 Vol.15 No.5

The removal of arsenic(V) using four different natural minerals were evaluated. Parameters like contact time, pH, adsorbent dosages, and As(V) concentration were optimized. The kinetics of adsorption was observed to be fast and reached equilibrium within 2h. As(V) adsorption on studied minerals was dependent on pH and followed a pseudo-second-order reaction model. For kaolin, maximum adsorption was found at pH 5.0. Whereas, in case of other three minerals, a pH range of 6.0-7.0 was found to be the best for As(V) adsorption. The maximum adsorption capacity (Q) was calculated by fitting Langmuir equation to the adsorption isotherms obtained under a specified condition. From the slope of best fit, the Q values were calculated to be 2.07, 2.15, 1.95 and 0.86 mg As(V)/g of bauxite, wad, iron ore and kaolin, respectively. Desorption of As(V) from loaded materials was dependent on the type of leaching reagents used. Based on the results, it was found that among the studied natural minerals, wad was the best As(V) adsorbent.

Photophysical behaviour of ground state anion and phototautomer of 3-hydroxyflavone in liposome membrane

Mohapatra, Monalisa,Subuddhi, Usharani,Mishra, Ashok K. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.10

A detailed account of the photophysical behaviour of the phototautomer (PT) and the ground state anion ($A^-$) of 3-hydroxyflavone in liposome membrane at various membrane conditions is presented. A quenching study with a hydrophilic quencher $Ag^+$ suggests that the phototautomeric emission generates from the fraction of 3HF that is located at the inner hydrophobic core, whereas the ground state anionic emission is from the fraction that resides near the water-accessible surface site. However, the biexponential nature of fluorescence decays of both the forms indicates that there is local heterogeneity in the distribution. Temperature dependence studies and experiments in the presence of ethanol reveal that, as the membrane becomes more fluid, redistribution of 3HF takes place between the two sites leading to increase in $A^-$ population. The temperature dependence of the fluorescence anisotropy change of PT shows good correlation with the phase change and shows a sharp drop at the transition temperature, whereas the corresponding change in the case of $A^-$ is gradual.

Effect of Cr-Rich Phase Precipitation on Magnetic and Mechanical Properties of Fe-20% Cr Alloy

Mohapatra, J. N.,Kamada, Y.,Kikuchi, H.,Kobayashi, S.,Echigoya, J.,Park, D. G.,Cheong, Y. M. IEEE 2011 IEEE transactions on magnetics Vol.47 No.10

<P>Magnetic Hysteresis Loop (MHL) and micro-Vickers hardness measurements were carried out in isothermal aged Fe-20 wt. % Cr alloy. The results were compared with the existing atom probe data at similar heat treated conditions. Coercivity and hardness of the alloy was increased and remanence of the alloy was decreased with the increase in ageing time. Such increase in the magnetic and mechanical hardness was due to the nucleation and growth of Cr rich α' phase. The size of the Cr rich α' phase precipitates were increased and the number density of the precipitates were decreased with the increase in ageing time observed by atom probe analysis. In this work a good correlation between hardness (H<SUB>v</SUB>) and coercivity (H<SUB>c</SUB>) was found with the combined effect of precipitate size (r) and number density (n). A linear relationship was found with the change in coercivity and hardness of the alloy indicating that the MHL technique would be a good Non-Destructive Evaluation (NDE) tool for the evaluation of thermal embrittlement in structural components made of Fe-Cr alloys.</P>

Comparative Study of Corner and Feature Extractors for Real-Time Object Recognition in Image Processing

Mohapatra, Arpita,Sarangi, Sunita,Patnaik, Srikanta,Sabut, Sukant The Korea Institute of Information and Commucation 2014 Journal of information and communication convergen Vol.12 No.4

Corner detection and feature extraction are essential aspects of computer vision problems such as object recognition and tracking. Feature detectors such as Scale Invariant Feature Transform (SIFT) yields high quality features but computationally intensive for use in real-time applications. The Features from Accelerated Segment Test (FAST) detector provides faster feature computation by extracting only corner information in recognising an object. In this paper we have analyzed the efficient object detection algorithms with respect to efficiency, quality and robustness by comparing characteristics of image detectors for corner detector and feature extractors. The simulated result shows that compared to conventional SIFT algorithm, the object recognition system based on the FAST corner detector yields increased speed and low performance degradation. The average time to find keypoints in SIFT method is about 0.116 seconds for extracting 2169 keypoints. Similarly the average time to find corner points was 0.651 seconds for detecting 1714 keypoints in FAST methods at threshold 30. Thus the FAST method detects corner points faster with better quality images for object recognition.

GCS Movement and Peace : Global Co-operation for a Global Society

Mohapatra, S.S. 慶熙大學校 밝은社會問題硏究所 2000 밝은社會硏究 Vol.21 No.1

전쟁과 평화는 동전의 양면(兩面)과 같다. 인간의 가치나 위대함은 평화의 과정을 통해서가 아니라 오로지 힘과 전쟁에 의해 단정되어 왔다. 오늘날에도 지구화와 신(新)제국주의 구실 하에 경제전쟁으로 치닫고 있다. 인도 철학자들은 인류문명에 대해 4단계로 언급하고 있다. 첫째, 단계는 진실(Truth-Satya)의 시대, 둘째는 투명성(Transparency-Tretaya)시대, 셋째는 진실과 거짓(Falsehood-Dwapar)이 교착하는 시대, 마지막 단계가 지금 인류가 사는 거짓의 시대다. 따라서 중요한 것은 이를 교육과 인간의 마음과 영혼 그리고 평화의 선무를 통해 인간을 변화시키는 일이다. 이렇게 해서 지구공동체를 이룩하게 된다. 노벨평화수상자인 타고르는 일찍이 1941년 文明의 危機를 논하면서 文明의 비젼은 서구 기술 물질 문명의 붕괴와 더불어 동방에서 올 것임을 예견했다. 그 동방은 중국과 한국을 의미한다. 영성(靈性)의 탐구로서 그는 '종교란 무엇인가'? 깊은 깨달음이며, 나와 우주간의 불사(不死)의 신비적 관계임을 강조했다. 인간은 완성(Integration)을 바라는 것이 기본적 욕구이다. 상호자기완성(Integrationl Integration)으로서 '새로운 영성(New Spirituality)'은 전인(全人-whole person)적 수련으로써 서구에서는 찾아볼 수 없는 육체적(肉體的) 요가수행을 통해 이루어진다. 이는 결국 정신분석학자인 프로이드와 융의 심리적 요법에 의한 자기통찰로 더 큰 깨달음을 얻게 되는 것과 같다. 평등과 정의로서 이 깨달음의 경지는 테레사 수녀, 킹목사, 간디 등에서 볼 수 있다. 새로운 영성의 마지막 국면은 나와 우주간의 화합완성의 욕구이다. 이는 20세기말에 와서 더욱 파괴된 환경 생태계에 대한 깨달음과도 연관된다. 다음 경계해야 할 것은 종교적 극단주의(religious extremlism)인데 예컨데 북 아일랜드의 구교(catholic)와 신교(protestant)간의 생사를 건 전쟁, 스리랑카, 중동전쟁 등은 오늘날 시대착오적이며 이해할 수 없는 싸움이다. 따라서 세계 종교화합운동은 지난 25년간 노력을 해 왔다. 간디는 일찌기 이를 위해 진력해 왔으며, 그 후 학자간의 연구과제로서도 상당한 진전이 있어 왔다. 1893년 시카고에서 개최된 세계종교집회(World Parliament of Religion) 개시 이래, 1968년 캘커타에서 개최된 제1회 영성정상회의(The Spiritual Summit Conference), 1970년 일본 교토에서의 종교와 평화에 관한 세계회의, 근래에는 1993년 시카고와 옥스퍼드에서의 종교간 대화를 통한 상호협력 노력이 광범위하게 전개되어 왔었다. 세계종교인은 이제 더 나은 세계를 위해 공동 노력과 활동을 취해야 한다. 적대감, 무지(無知), 편견을 지양하고 평화와 화해의 사도가 되어야 한다. 오늘날 인류가 직면한 최대위기는 빈곤, 폭력, 환경공해이다. 이는 바로 정신적, 윤리적 과제에 근원을 두고 있다. 세계인민을 먹일 수 있는 충분한 자원이 있음에도 서로 나누어 가질 의사가 없다는 점이다. 그러므로 가장 중요한 것은 인간의 기본적인 윤리의 확립이다. 즉, 모든 인간 존재는 성(性), 인종, 피부, 언어, 종교간의 차이없이 인간답게 대접받고 인간답게 살아야 한다는 점이다.