Crack Detection in Pillars Using Infrared Thermographic Imaging

Seo, H.,Choi, H.,Park, J.,Park, J.,Lee, I.-M. ASTM International 2017 Geotechnical testing journal Vol.40 No.3

Highly selective fluorescent probe for sequential recognition of copper(II) and iodide ions

Seo, H.,An, M.,Kim, B.Y.,Choi, J.H.,Helal, A.,Kim, H.S. Pergamon Press 2017 Tetrahedron Vol.73 No.31

A new highly selective fluorescent probe based on 2-(2'-aminolphenyl)-4-hydroxymethylthiazole (1) was developed for the detection of copper and iodide ions in ethanol. Probe 1 selectively detected Cu<SUP>2+</SUP> through a ''switch off'' response, showing a good association constant (K<SUB>a</SUB> = 1.43 x 10<SUP>5</SUP> M<SUP>-1</SUP>) and binding with Cu<SUP>2+</SUP> ions in a 1:1 stoichiometry. An in situ generated 1-Cu<SUP>2+</SUP> (1:1) ensemble detected I<SUP>-</SUP> ions sequentially through a ''switch on'' response. The ''switch off'' response occurred with selective complexation of Cu<SUP>2+</SUP> ions due to intramolecular charge transfer (ICT). An ensemble of 1 and copper(II) showed higher selectivity towards iodide than towards any other anions due to the reduction of Cu<SUP>2+</SUP> to Cu<SUP>+</SUP> by I<SUP>-</SUP> and subsequent complexation with 1.

Histogram-based mixed-signal time-to-digital-converter array for direct time-of-flight depth sensors

Seo, H.,Choi, J. Institution of Electrical Engineers 2019 Electronics letters Vol.55 No.6

WC31-3: Capacity Region of Multiuser Shared Channel When Available Transmission Power Is Time-Varying

Seo, H.,Park, D.,Lee, B. G. INSTITUTE OF ELECTRICAL ENGINEERS INC (IEE) 2005 IEEE international conference on communications Vol.2005 No.4

Salivary Lipocalin Is Uniquely Expressed in the Uterine Endometrial Glands at the Time of Conceptus Implantation and Induced by Interleukin 1Beta in Pigs

Seo, H.,Kim, M.,Choi, Y.,Ka, H. SOCIETY FOR THE STUDY OF REPRODUCTION 2011 BIOLOGY OF REPRODUCTION Vol.84 No.2

Measurements and visualization of velocity profiles in a scaled CANDU6 moderator tank using particle image velocimetry

Seo, H.,Kim, H.T.,Cha, J.E.,Bang, I.C. Pergamon Press ; Elsevier Science Ltd 2014 Annals of nuclear energy Vol.73 No.-

The moderator tank in a CANDU reactor plays a key role in the reactor core including the fuel channels and moderator. Understanding the circulation characteristics such as the flow pattern and temperature distribution in the moderator tank is important because the cooling capability is limited inside the fuel channels in the worst accident scenarios such as large break loss of coolant accident, resulting in heat removal through the Calandria tubes contacting with the fuels via thermal expansion. Therefore, measurement of the velocity profile and temperature distribution in the moderator tank is a key factor in the safety analysis of CANDU reactors because the moderator tank provides ultimate heat sink. In the present work, the velocity profile in a scaled CANDU6 moderator tank was obtained using particle image velocimetry from the 1st and 2nd jet orifices under symmetric and asymmetric flow conditions. The scaled moderator tank was prepared with acrylic, which is transparent to allow the laser penetration to create the light sheet for illuminating tracer particles. The velocity profile in the scaled moderator tank was obtained from the inlet nozzle running to the top of the tank along and near the curved wall surface and compared to a commercial CFD code, CFX.

Optimization of hybrid-type instrumentation for Pu accountancy of U/TRU ingot in pyroprocessing

Seo, H.,Won, B.H.,Ahn, S.K.,Lee, S.K.,Park, S.H.,Park, G.I.,Menlove, S.H. Pergamon Press 2016 Applied radiation and isotopes Vol.108 No.-

One of the final products of pyroprocessing for spent nuclear fuel recycling is a U/TRU ingot consisting of rare earth (RE), uranium (U), and transuranic (TRU) elements. The amounts of nuclear materials in a U/TRU ingot must be measured as precisely as possible in order to secure the safeguardability of a pyroprocessing facility, as it contains the most amount of Pu among spent nuclear fuels. In this paper, we propose a new nuclear material accountancy method for measurement of Pu mass in a U/TRU ingot. This is a hybrid system combining two techniques, based on measurement of neutrons from both (1) fast- and (2) thermal-neutron-induced fission events. In technique #1, the change in the average neutron energy is a signature that is determined using the so-called ring ratio method, according to which two detector rings are positioned close to and far from the sample, respectively, to measure the increase of the average neutron energy due to the increased number of fast-neutron-induced fission events and, in turn, the Pu mass in the ingot. We call this technique, fast-neutron energy multiplication (FNEM). In technique #2, which is well known as Passive Neutron Albedo Reactivity (PNAR), a neutron population's changes resulting from thermal-neutron-induced fission events due to the presence or absence of a cadmium (Cd) liner in the sample's cavity wall, and reflected in the Cd ratio, is the signature that is measured. In the present study, it was considered that the use of a hybrid, FNEMxPNAR technique would significantly enhance the signature of a Pu mass. Therefore, the performance of such a system was investigated for different detector parameters in order to determine the optimal geometry. The performance was additionally evaluated by MCNP6 Monte Carlo simulations for different U/TRU compositions reflecting different burnups (BU), initial enrichments (IE), and cooling times (CT) to estimate its performance in real situations.

Subchannel analysis of a small ultra-long cycle fast reactor core

Seo, H.,Kim, J.H.,Bang, I.C. North-Holland Pub. Co 2014 Nuclear engineering and design Vol.270 No.-

Thermal-hydraulic evaluation of a small ultra-long cycle fast reactor (UCFR) core is performed based on existing safety regulations. The UCFR is an innovative reactor newly designed with long-life core based on the breed-and-burn strategy and has a target electric power of 100MWe (UCFR-100). Low enriched uranium (LEU) located at the bottom region of the core play the role of igniter to operate the UCFR for 60 years without refueling. A metallic form is selected as a burning fuel region material after the LEU location. HT-9 and sodium are used as cladding and coolant materials, respectively. In the present study, MATRA-LMR, subchannel analysis code, is used for evaluating the safety design limit of the UCFR-100 in terms of fuel, cladding, and coolant temperature distributions in the core as design criteria of a general fast reactor. The start-up period (0 year of operation), the middle of operating period (30 years of operation), and the end of operating cycle (60 years of operation) are analyzed and evaluated. The maximum cladding surface temperature (MCST) at the BOC (beginning of core life) is 498<SUP>o</SUP>C on average and 551<SUP>o</SUP>C when considering peaking factor, while the MCST at the MOC (middle of core life) is 498<SUP>o</SUP>C on average and 548<SUP>o</SUP>C in the hot channel, respectively, and the MCST at the EOC (end of core life) is 499<SUP>o</SUP>C on average and 538<SUP>o</SUP>C in the hot channel, respectively. The maximum cladding surface temperature over the long cycle is found at the BOC due to its high peaking factor. It is found that all results including fuel rods, cladding, and coolant exit temperature are below the safety limit of general SFR design criteria.

Development of prototype induced-fission-based Pu accountancy instrument for safeguards applications

Seo, H.,Lee, S.K.,An, S.J.,Park, S.H.,Ku, J.H.,Menlove, H.O.,Rael, C.D.,LaFleur, A.M.,Browne, M.C. Pergamon Press 2016 Applied radiation and isotopes Vol.115 No.-

Prototype safeguards instrument for nuclear material accountancy (NMA) of uranium/transuranic (U/TRU) products that could be produced in a future advanced PWR fuel processing facility has been developed and characterized. This is a new, hybrid neutron measurement system based on fast neutron energy multiplication (FNEM) and passive neutron albedo reactivity (PNAR) methods. The FNEM method is sensitive to the induced fission rate by fast neutrons, while the PNAR method is sensitive to the induced fission rate by thermal neutrons in the sample to be measured. The induced fission rate is proportional to the total amount of fissile material, especially plutonium (Pu), in the U/TRU product; hence, the Pu amount can be calibrated as a function of the induced fission rate, which can be measured using either the FNEM or PNAR method. In the present study, the prototype system was built using six <SUP>3</SUP>He tubes, and its performance was evaluated for various detector parameters including high-voltage (HV) plateau, efficiency profiles, dead time, and stability. The system's capability to measure the difference in the average neutron energy for the FNEM signature also was evaluated, using AmLi, PuBe, <SUP>252</SUP>Cf, as well as four Pu-oxide sources each with a different impurity (Al, F, Mg, and B) and producing (α,n) neutrons with different average energies. Future work will measure the hybrid signature (i.e., FNEMxPNAR) for a Pu source with an external interrogating neutron source after enlarging the cavity size of the prototype system to accommodate a large-size Pu source (~600g Pu).

Constrained Texture Mapping using Image Warping

Seo, H.,Cordier, F. Blackwell Publishing Ltd 2010 Computer Graphics Forum Vol.29 No.1

<P>Abstract</P><P><I>We introduce in this paper a new method for smooth foldover-free warping of images. It allows users to specify the constraints in two different ways: positional constraints to constrain the position of points in the image and gradient constraints to constrain the orientation and scaling of some parts of the image. We then show how our method is used for texture mapping with hard constraints. We start with an unconstrained planar embedding of the target mesh calculated with conventional methods. In order to obtain a mapping that satisfies the user-defined constraints, we use our warping method to align the features of the texture image with those of the unconstrained embedding. Compared to previous work, our method generates a smoother texture mapping and offers higher level of control for defining the constraints.</I></P>