관계형 데이터베이스 기반 ABox Reasoning

Ankesh Khandelwal(Ankesh Khandelwal) 오정정(Summit Bisai),김주리(Kim Ju-Ri),이현창(Lee Hyun-Chang),한성국(Han Sung-Kook) 한국IT서비스학회 2009 한국IT서비스학회 학술대회 논문집 Vol.2009 No.1

OWL 온톨로지의 확장 가능한(scalable) 추론(reasoning)에 대한 접근 방법으로 SQL로 구축된 논리 규칙을 관계형 데이터베이스에 저장되어있는 개체(individual)에 대한 사실(facts)과 공리(axioms)들에 적용하는 것이다. 예로서 미네르바(Minerva)는 서술 논리 프로그램(Description Logic Program, DLP)을 적용함으로써 ABox 추론을 수행한다. 본 연구에서는 관계형 데이터베이스를 기반으로 추론을 시도하며, 대규모 논리 규칙 집합을 사용한 추론을 시도한다. 뿐만 아니라, 특정 클래스에 속한 익명(anonymous)의 개체들과 개체들의 묵시적(implicit)인 관계성 추론을 시도하며, 필요한 경우 새로운 개체를 생성함으로써 명시화하여 추론을 시도한다. 더욱이, 추론의 논리 패러다임(paradigm)에서부터 데이터베이스 패러다임에 이르기까지 변화 시켜가면서 카디널리티(cardinality) 제약을 만족하는 개체들에 대한 제약적인 추정 추론을 시도하며, 벤치마크 테스트 결과 향상된 추론 능력을 얻을 수 있음을 보인다.

Trash to energy: A facile, robust and cheap approach for mitigating environment pollutant using household triboelectric nanogenerator

Khandelwal, Gaurav,Chandrasekhar, Arunkumar,Alluri, Nagamalleswara Rao,Vivekananthan, Venkateswaran,Maria Joseph Raj, Nirmal Prashanth,Kim, Sang-Jae Elsevier 2018 APPLIED ENERGY Vol.219 No.-

<P><B>Abstract</B></P> <P>The plastic pollution often observed on seashores is indicative of a greater problem manifesting in the oceans. However, such pollution mostly emanates from land-based sources. To help mitigate the problem of plastic pollution, we describe herein a waste material-based household triboelectric nanogenerator (H-TENG) that operates in the vertical contact-separation mode. The device takes less than 5 min to fabricate and can be made in-house from recyclable materials without the need for scientific equipment or laboratory expertise. The device was made using randomly selected waste materials. The maximum peak-to-peak voltage generated was 44 V, and the corresponding peak-to-peak short-circuit current (I<SUB>SC</SUB>) generated was 289 nA. The H-TENG was systematically studied and showed the capability to exploit biomechanical energy to operate liquid crystal displays (LCDs) and light-emitting diodes (LEDs). Furthermore, we demonstrated how the H-TENG could be used as a dynamic force sensor for small dynamic force detection. Finally, we discuss applications of H-TENGs in an in-house emergency direction system, security system and a magnetically attachable/detachable smart chopping board.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Circumvention of plastic pollution using H-TENG. </LI> <LI> Fabrication is straightforward, cheap and needs <5 min. </LI> <LI> All the materials used in the fabrication are recycled waste materials. </LI> <LI> Fabrication is possible at any place without the need for scientific equipment. </LI> <LI> Demonstration of the biomechanical energy harvesting, emergency direction system, etc. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Single precursor mediated one-step synthesis of ternary-doped and functionalized reduced graphene oxide by pH tuning for energy storage applications

Khandelwal, Mahima,Li, Yuanyuan,Molla, Aniruddha,Hyun Hur, Seung,Suk Chung, Jin Elsevier 2017 Chemical engineering journal Vol.330 No.-

<P><B>Abstract</B></P> <P>The present work reports for the first time a one-step hydrothermal synthesis of ternary-doped (N, S, and P) reduced graphene oxide (rGO) under acidic pH conditions (NSPrGO2-12) using thiamine pyrophosphate (TPP) as both a reducing agent and a single source N, S, and P doping agent under mild experimental conditions. The change in pH of the reaction mixture from acidic (∼2.2) to basic (∼8.5) creates a change in the surface chemistry of rGO, resulting in TPP-functionalized rGO with modified morphology, structure, surface area and electrochemical performance. This change has been analyzed in terms of the different interactions between the graphene oxide functional groups and various functionalities of TPP at different pH conditions. Under acidic pH conditions, the sample had a crumpled sheet morphology with wrinkles on its surface having interconnected network and possessing a relatively large surface area. Meanwhile, under basic pH conditions, the sample exhibited stacked layer-by-layer sheets that formed an aggregated network-like structure with a smaller surface area. NSPrGO2-12 delivers a high specific capacitance (C<SUB>s</SUB>) value of 269F/g at 20A/g with long cyclic stability (93% retention after 5000 cycles at 20A/g), high coulombic efficiency (100%) and high energy/power density (23.55Wh/kg/7923.4W/kg) in an aqueous electrolyte. Moreover, the C<SUB>s</SUB> value of the ternary-doped rGO is significantly higher than its mono- and co-doped counterparts under similar experimental conditions. These features clearly demonstrate the tremendous potential of NSPrGO2-12 as an electrode material for energy storage applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A one-step synthesis of ternary (N, S and P) – doped rGO is demonstrated. </LI> <LI> Thiamine pyrophosphate act as single source precursor for N, S and P dopants. </LI> <LI> Change in pH from acidic (∼2.2) to basic (∼8.5) results in functionalized rGO. </LI> <LI> The resulted tri-doped rGO showed high capacitance of 269F/g at 20A/g. </LI> <LI> Tri-doped rGO shows excellent cycling stability and high energy/power density. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Multi-Electron Donor Organic Molecules Containing Hydroquinone Methyl-Ether as Redox Active Units

Khandelwal, Manish,Hwang, In-Chul,Nair, Prakash Chandran R.,Lee, Jung-Woo Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.4

Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.

Chemically controlled <i>in-situ</i> growth of cobalt oxide microspheres on N,S-co-doped reduced graphene oxide as an efficient electrocatalyst for oxygen reduction reaction

Khandelwal, Mahima,Chandrasekaran, Sundaram,Hur, Seung Hyun,Chung, Jin Suk Elsevier 2018 Journal of Power Sources Vol.407 No.-

<P><B>Abstract</B></P> <P>A chemically controlled facile approach is developed for the <I>in-situ</I> growth of Co<SUB>3</SUB>O<SUB>4</SUB> microspheres on N,S-co-doped rGO sheets (Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO) employing thiamine hydrochloride (THCl) (7.41 mM) as the N and S co-doping agent under mild experimental conditions. The THCl concentration plays a vital role in controlling the growth of cobalt crystals anchored on the surface of N,S-rGO. The change in concentration of THCl from 7.41 to 22.20 mM alters the deposition of cobalt crystal on the N,S-rGO surface from Co<SUB>3</SUB>O<SUB>4</SUB> to Co<SUB>9</SUB>S<SUB>8</SUB> (Co<SUB>9</SUB>S<SUB>8</SUB>/N,S-rGO). This change is understood due to the formation of different intermediate complex structure driven by supramolecular interactions. The altered cobalt crystal phase leads to tuned morphologies, surface areas and catalytically active centers which are investigated by various characterization techniques. Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO exhibits superior electrocatalytic activity for oxygen reduction reaction (ORR) compared to Co<SUB>9</SUB>S<SUB>8</SUB>/N,S-rGO. Moreover, Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO shows more positive onset potential (0.90 V vs. RHE), half-wave potential (0.74 V vs. RHE), relatively high limiting current density and smaller Tafel slope (52 mV per decade) compared to its separate components owing to synergistic effects. Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO hybrid also outperforms the electrocatalytic activity of commercial Pt/C in terms of durability and methanol tolerance under alkaline conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A facile synthesis of Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO was achieved by using thiamine hydrochloride. </LI> <LI> Thiamine hydrochloride controlled the growth and phase of cobalt crystal on N,S-rGO. </LI> <LI> ORR activity of Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO hybrid was enhanced due to synergistic effect. </LI> <LI> Active sites and electroactive surface area were found to be vital for improved ORR. </LI> <LI> Co<SUB>3</SUB>O<SUB>4</SUB>/N,S-rGO hybrid showed better durability and methanol tolerance than Pt/C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Model to Predict Temperature and Capillary Pressure Driven Water Transport in PEFCs After Shutdown

Khandelwal, Manish,Lee, Sungho,Mench, M. M. The Electrochemical Society 2009 Journal of the Electrochemical Society Vol.156 No.6

Comparison of Propofol and Ketofol on Transcranial Motor Evoked Potentials in Patients Undergoing Thoracolumbar Spine Surgery

Khandelwal Ankur,Chaturvedi Arvind,Sokhal Navdeep,Singh Akanksha,Sharma Hanjabam Barun 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.2

Study Design: This was a double-blind randomized study. Purpose: The primary purpose was to compare the effects of propofol and ketofol on amplitudes and latencies of transcranial motor evoked potentials (TcMEPs) during thoracolumbar spine surgery. In addition, intraoperative hemodynamics and muscle power were compared. Overview of Literature: Propofol is commonly used during intraoperative TcMEP monitoring. However, propofol inhibits TcMEP amplitudes and causes hypotension in a dose-dependent fashion. Methods: Amplitude and latency of TcMEPs were recorded bilaterally from the abductor pollicis brevis (APB) and abductor hallucis (AH) muscles in 38 adult American Society of Anesthesiologists I and II patients undergoing thoracolumbar spine surgery. Baseline recordings of TcMEPs in both groups were recorded under propofol infusion. Group X patients then received propofol and fentanyl (1 mcg/kg/hr), and group Y patients received ketofol and fentanyl (1 mcg/kg/hr). Bispectral index was maintained at 40–60 in both groups. Amplitude and latency were recorded at 30 minutes intervals for 2 hours. Results: Propofol caused no significant changes in amplitude and latency in any muscle. In contrast, amplitude increased significantly at all time points in the bilateral APB muscles and 60, 90, and 120 minutes in the left AH muscle without changes in latency in response to ketofol. When the two groups were compared, ketofol induced significantly higher amplitudes at 60, 90, and 120 minutes in the (left) APB, at all time points in the (right) APB, and at 120 minutes in both AH muscles, compared with propofol. Blood pressures were lower and fluid and vasopressor requirements were higher in group X. Muscle power was similar between the two groups. Conclusions: Ketofol facilitates TcMEP amplitudes without affecting latency. Use of ketofol resulted in a better and more stable hemodynamic profile than did use of propofol.

Surface modification of co-doped reduced graphene oxide through alkanolamine functionalization for enhanced electrochemical performance

Khandelwal, Mahima,Li, Yuanyuan,Hur, Seung Hyun,Chung, Jin Suk The Royal Society of Chemistry 2018 NEW JOURNAL OF CHEMISTRY Vol.42 No.2

<P>This manuscript presents the facile synthesis of alkanolamine functionalized N,S co-doped reduced graphene oxide (NSrGO) using thiamine hydrochloride as a reducing and co-doping agent for N and S, and triethanolamine (TEA) as a functionalizing agent. The functionalization of TEA molecules on N,S co-doped rGO (TEA-NSrGO) was confirmed by FTIR and XPS analyses. Chemical functionalization of TEA on the surface of NSrGO minimizes restacking of the co-doped sheets and results in an enhanced surface area, as was evidenced by FESEM, TEM, and BET measurements. Moreover, the formation of oxygen-containing groups on NSrGO <I>via</I> covalent functionalization of TEA molecules effectively tunes the surface chemistry of NSrGO, making the electrode material accessible to electrolyte ions. Interestingly, the synergistic effect of TEA functionalization and co-doping in rGO results in impressive electrochemical performance, with a high specific capacitance value of 363 F g<SUP>−1</SUP> at 20 A g<SUP>−1</SUP>, outstanding cycling stability (91% retention after 10 000 cycles at 20 A g<SUP>−1</SUP>), high coulombic efficiency (99.5-100%), and high energy/power density (31.86 W h kg<SUP>−1</SUP>/7646 W kg<SUP>−1</SUP>). These electrochemical features suggest the potential of this electrode material for energy storage applications.</P>

Phase inversion enabled energy scavenger: A multifunctional triboelectric nanogenerator as benzene monitoring system

Khandelwal, Gaurav,Chandrasekhar, Arunkumar,Pandey, Rajagopalan,Maria Joseph Raj, Nirmal Prashanth,Kim, Sang-Jae Elsevier Sequoia 2019 Sensors and actuators. B Chemical Vol.282 No.-

<P><B>Abstract</B></P> <P>Mechanical energy harvesting using Triboelectric nanogenerator (TENG) based on the coupling of electrostatic induction and contact electrification is a cost-effective and straightforward process. TENG is well known for harnessing the waste energy at a large scale. Here, we demonstrated the fabrication of enhanced-performance TENG in contact-separation mode by utilizing the facile phase inversion process for only one triboactive layer. The phase inversion is a straightforward technique to achieve films with a porous structure and high crystallinity. The non-piezoelectric, semiconducting TiO<SUB>2</SUB> microparticle acts as charge trapping sites attributed to their high dielectric constant. The PVDF-10-TiO<SUB>2</SUB>/CA TENG showed 7 times and 10 times enhancement for voltage and short circuit current compared to the PVDF-TiO<SUB>2</SUB>/CA TENG prepared without phase inversion process. Furthermore, the device is a multifunctional energy harvester i.e. it can harvest biomechanical as well as wind energy. Finally, we demonstrated the use of TENG device for volatile organic compounds (VOCs) sensing. The device exhibits good response with the change in concentration as well as total flow rate. The voltage decreases with the increase in the benzene concentration. The sensitivity of as fabricated sensor is 0.0035 V/ppm concerning concentration and 0.29176 V/sccm concerning total flow rate. The sensor was integrated with the Arduino Uno for automatic detection of benzene giving the alarm warning for the presence of benzene in the environment. This work extended the application of TENG in the field of VOCs sensing, design and concept which can be applied in the future for the detection of other VOCs in the environment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phase inversion and semi conducting TiO<SUB>2</SUB> based TENG with enhanced performance. </LI> <LI> The TENG shows 7 times and 10 times enhancement for voltage and current. </LI> <LI> Fabricated TENG is multifunctional energy harvester. </LI> <LI> Demonstration of TENG as VOC’s sensor with good selectivity and sensitivity. </LI> <LI> Integration of TENG with Arduino for warning message and alarm to evacuate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced Electroactivity and Genomic Profile of Pseudomonas aeruginosa PBH03 with Various Electron Shuttles

Himanshu KHANDELWAL,Sakuntala MUTYALA,Da Seul KONG,Jung Rae KIM 한국생물공학회 2022 한국생물공학회 학술대회 Vol.2022 No.4