Multilateral approaches for investigation of particle stickiness of coal ash at low temperature fouling conditions

Namkung, Hueon,Kim, Hyung-Taek,Wang, Fuchen,Lin, Kuangfei,Yu, Guangsuo Springer-Verlag 2017 Korean Journal of Chemical Engineering Vol.34 No.12

<P>Particle stickiness is a key parameter for increasing ash deposition in gasification process. We conducted multilateral investigations to evaluate particle stickiness of coal ash at low temperature fouling conditions through Watt and Fereday's viscosity model, dilatometry (DIL) and laser flash apparatus (LFA) technique. Seventeen coals were employed for ash deposition experiments under gasification condition through drop tube furnace (DTF). The low viscosity not only led to increasing ash deposition behavior, but also increasing the particle size of deposited ash. From DIL analysis, the ash sintering behavior increased with increasing temperature due to increase of particle stickiness. The high amount of Fe2O3, CaO and MgO components resulted in low sintering temperature and high reduction of physical length. Through LFA analysis, the thermal conductivity increased with increasing temperature, because of increasing particle stickiness. In addition, its value was correlated with the propensity of common fouling indices.</P>

A Study on Nonresponse Errors in the Internet Survey

Namkung, Pyong,Kim, Min Jung 한국통계학회 2002 Communications for statistical applications and me Vol.9 No.3

The advantage of internet survey compared to the traditional survey methods are speedy in data collection, cost-effective, high performed design and able to data process and analysis at the same time. The other side are difficult to select sample, come from serious nonresponse errors. We suggest the new internet survey method to the questionnaire design that have the high response rate, enough to advanced preparations and system stability.

New evaluation measures for multifactor dimensionality reduction classifiers in gene-gene interaction analysis.

Namkung, Junghyun,Kim, Kyunga,Yi, Sungon,Chung, Wonil,Kwon, Min-Seok,Park, Taesung Oxford University Press 2009 Bioinformatics Vol.25 No.3

<P>Gene-gene interactions are important contributors to complex biological traits. Multifactor dimensionality reduction (MDR) is a method to analyze gene-gene interactions and has been applied to many genetics studies of complex diseases. In order to identify the best interaction model associated with disease susceptibility, MDR classifiers corresponding to interaction models has been constructed and evaluated as a predictor of disease status via a certain measure such as balanced accuracy (BA). It has been shown that the performance of MDR tends to depend on the choice of the evaluation measures.</P>

A New Species of Cave Dwelling Grylloblattoidea (Grylloblattidae) from Korea

Namkung, Joon 한국곤충학회 1974 Korean journal of entomology Vol.4 No.1

원시무시곤충으로 주목되고 있는 Grylloblattoidea는 1914년 E.M. Walker가 최초로 발표한 이래, 북미각지에서 7종.2아종, 일본에서 5종, Siberia에서 1종이 기재된 바 있으나 우리나라에서는 아직껏 밝혀진 바가 없다. 저자는 1966년 6월 보한강상류인 정선군 비룡동굴에서 완전한 1성웅을 채집한 바 있어 여기에 Gallcisiana biryongensis(비룡갈르와 벌레)로 명명 기재한다. 본종은 다양색.무안.체장 34mm로 기지의 어느 것보다도 대형종이다. 대체적구조는 일본산 Galloisiana nipponensis에 닮으나 제10복배판 끝 Supra-anal plate가 둔만년필촉과 같이 무듸게 되며, 북미종과는 부절욕반이 있음에서 외관상으로도 분명히 구별된다. 본종의 중요 표징은 다음과 같다. (1) 두부는 편본하고 폭이 약간 넓은 원형으로 두개선이 명료하고, 복안은 퇴화되었으나 강대한 안부강모가 나있다. (2) 전흉배는 저대한 정방형, 중흉배는 전변이 좁은 제형, 후흉배는 전변이 약천 좁은 제형으로 각 측연과 중앙부에 불규칙한 강모가 나있다. (3) 복배판은 제4, 5절이 최대이며, 각 절의 하변에 8개, 측연에 1개씩의 강모가 정열하며 제10배판 끝은 순한 만년필촉 꼴로 일견 2분 된 듯한 감을 준다. (4) 미모는 9절로 되며, 각 말단부에 3,4재의 장강모가 나 있고, 미세 투명한 긴 감각모가 보인다. (5) 보각은 완장하며 부절욕반이 명료하다. (6) 웅생식기관은 복잡한 구조를 갖추며, 복지는 좌우비대칭으로 좌지는 폭광인 ?꼴이고, 우지는 장삼각형으로 기부끝에 투명한 단추꼴 돌기가 보인다. (7) 대형의 주름진 반전낭이 우음경엽부에서 돌출하고 있으며, 비교적 완장한 주음경과 부음경이 보인다.

Hint for association of single nucleotide polymorphisms and haplotype in SPINK5 gene with atopic dermatitis in Koreans

Namkung, Jung‐,Hyun,Lee, Jong‐,Eun,Kim, Eugene,Byun, Ji‐,Yeon,Kim, Sook,Shin, Eun‐,Soon,Cho, Eun‐,Young,Yang, Jun‐,Mo Blackwell Publishing Ltd 2010 Experimental dermatology Vol.19 No.12

<P><B>Abstract: </B> Clinical studies, including twin studies, support the concept that the risk of atopic dermatitis (AD) may be mediated through skin‐specific genes, rather than simply through systemic immune or atopy risk genes. The SPINK5 gene is expressed on epithelial surfaces and may provide protection against other allergenic serine proteases. Mutations in the SPINK5 gene result in Netherton syndrome, a disorder characterised by AD, ichthyosis, and elevated serum IgE levels. We genotyped 21 single nucleotide polymorphisms (SNPs) from the SPINK5 gene for 1090 case–control samples (631 patients with AD and 459 normal controls) and analysed the SNPs and haplotypes in this gene and also searched for gene–gene interactions between SPINK5 and the DEFB1 gene that we previously reported. Six SNPs [rs17718511 (<I>P </I>= 0.026), rs17860502 (<I>P </I>= 0.024), KN0001820 (<I>P </I>= 0.045), rs60978485 (<I>P </I>= 0.007), rs17718737 (<I>P </I>= 0.02), and rs1422985 (<I>P </I>= 0.038)] and the haplotype TAA (rs60978485, rs6892205, rs2303064; <I>P </I>= 0.023) in the SPINK5 gene showed significant different allelic or genotypic distributions between the AD group and the control group. We also found that four SNPs [rs17718511 (<I>P </I>= 0.033), rs17860502 (<I>P </I>= 0.031), rs60978485 (<I>P </I>= 0.005), rs17718737 (<I>P </I>= 0.023)] and the haplotype TAA (<I>P </I>= 0.02) in the SPINK5 gene showed associations with the susceptibility of the allergic type of AD (ADe). In addition to this finding, we speculate that the SNPs from DEFB1 and SPINK5 affect the individual susceptibility to development of ADe in an additive manner. This study provides evidence for a significant interaction between allergens and the SPINK5 gene that may contribute to ADe susceptibility.</P>

Effect of mineral components on sintering of ash particles at low temperature fouling conditions

Namkung, H.,Xu, L.H.,Kim, C.H.,Yuan, X.,Kang, T.J.,Kim, H.T. Elsevier Scientific Pub. Co 2016 Fuel processing technology Vol.141 No.1

The ash deposition phenomenon in the coal gasification process is a severe problem for continuous operation. The ash deposition rate is influenced by the behavior of ash particles on the deposit target. Dropped coal ash particles, which exhibit different behaviors on the deposit surface such as attachment, rebounding, and removal, were observed through the view port of a drop tube furnace (DTF). The different behaviors may be influenced by the state of the ash particles such as the sintering phenomenon, which is a function of the mineral content. To verify the mineral components important in sintering among the ash particles, transformation of the particle shape of synthetic ash reacted at 900<SUP>o</SUP>C was analyzed through a scanning electron microscope (SEM). The Fe, Ca, and Mg components were the main factors for sintering and agglomeration. The Fe, Ca, and Mg components sintered with Si and Al were observed in the mineral mapping of deposited coal ash by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) analysis. Sintering characteristics of coal ash were analyzed by the dilatometer technique. Sintering temperature, shrinkage, and sintering activation energy (E<SUB>sin</SUB>) were all found to be related to the Fe, Ca, and Mg contents.

Characteristics of novel synthetic fuels using coal and sewage sludge impregnated bioliquid applying for a coal combustion system

Namkung, Hueon,Park, Ju-Hyoung,Lee, Young-Joo,Song, Gyu-Seob,Choi, Jong Won,Kim, Joeng-Geun,Park, Jun-Su,Um, Byung Hwan,Song, Kwang Ho,Park, Se-Joon,Choi, Young-Chan Elsevier 2017 Fuel processing technology Vol.167 No.-

<P><B>Abstract</B></P> <P>The application of biomass resources and sewage sludge is currently the most important issue in the field of coal combustion systems. The main drawback for operating a boiler system is its varied firing characteristics and low heating value. In this study, we have developed new synthetic fuels, namely hybrid sludge fuel (HSF), using coal and sewage sludge impregnated bioliquid (molasses) and evaluated their properties by comparison with conventional fuels. To prepare the HSF, it was treated in a carbonization system at 250°C. Depending on the van Krevelen diagram, the fuel quality of HSF was superior to that of raw bioliquid and sewage sludge. In addition, its fuel characteristic was similar to sub-bituminous and bituminous coal. Thermogravimetric analysis (TGA) indicated only a single-stage combustion pattern for HSF during non-isothermal heating. To clarify the unburned carbon (UBC) content, an ultimate analysis was conducted. The amount of UBC of the HSF was much more than that of sewage sludge, but less than that of coal. To investigate the surface hydrophobicity of HSF, Fourier transform infrared spectroscopy (FT-IR) analysis and a moisture re-adsorption test were carried out. The HSF possessed high hydrophobicity and presented a low moisture re-adsorption rate compared to conventional fuels.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The new synthetic fuel (HSF) using coal and sewage sludge impregnated bioliquid was investigated. </LI> <LI> HSF properties were similar to sub-bituminous and bituminous coal on the van Krevelen diagram. </LI> <LI> HSF showed single-stage combustion characteristics from the thermogravimetric analysis. </LI> <LI> HSF presented higher fuel reactivity in comparison with low reactivity coal. </LI> <LI> HSF had a higher hydrophobicity on the surface. </LI> </UL> </P>

Optimal sequential state discrimination between two mixed quantum states

Namkung, Min,Kwon, Younghun American Physical Society 2017 Physical review. A Vol.96 No.2

<P>Recently, sequential state discrimination, as a quantum-key distribution protocol, has been proposed for multiple receivers. A previous study [J. A. Bergou et al., Phys. Rev. Lett. 111, 100501 (2013)] showed that every receiver could successfully perform a sequential state discrimination of two pure states with identical prior probabilities. In this study, we extend the sequential state discrimination to mixed states with arbitrary prior probability. First, we analytically obtain the condition of the receiver's optimal measurement. In addition, we show that the optimal probability for every receiver to share the mixed state prepared by the sender is not zero. Furthermore, we compare the sequential state discrimination to the strategies of quantum reproducing and quantum broadcasting. We find that there are cases in which, unlike that of the pure state, the sequential state discrimination of mixed states shows a better performance than the other strategies.</P>

Allocation in Multi-way Stratification by Linear Programing

NamKung, Pyong,Choi, Jae-Hyuk 한국통계학회 2006 Communications for statistical applications and me Vol.13 No.2

Winkler (1990, 2001), Sitter and Skinner (1994), Wilson and Sitter (2002) present a method which applies linear programing to designing surveys with multi-way stratification, primarily in situation where the desired sample size is less than or only slightly larger than the total number of stratification cells. A comparison is made with existing methods both by illustrating the sampling schemes generated for specific examples, by evaluating sample mean, variance estimation, and mean squared errors, and by simulating sample mean for all methods. The computations required can, however, increase rapidly as the number of cells in the multi-way classification increase. In this article their approach is applied to multi-way stratification using real data.

Understanding non-classical correlation using optical hybrid states in noisy quantum channels

Namkung, Min,Kwon, Younghun IOP 2018 JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL Vol.51 No.45

<P>In this article we investigate the non-classical correlation in a macroscopic physical system. As a tool, we consider an optical hybrid state that is a micro–macro entangled state. Our strategy is to study the behavior of non-classical correlation in an optical hybrid state that may go through noisy channels. We study the violation of two inequalities, which are the CHSH-inequality and the (generalized) CHSH-like-inequality, as measures of non-classical correlation. First, we find that when on/off or parity measurements are used for the side of the coherent state in an optical hybrid state, the violation of the CHSH-inequality is the same as that of the (generalized) CHSH-like-inequality. Second, we see that each measurement provides a different value of violation of (generalized) CHSH-inequality when it is an optical hybrid state that goes through noisy channels. A suprising result is that the on/off measurement can provide a violation of CHSH-inequality (or (generalized) CHSH-like-inequality) for an optical hybrid state with any amount of colored noise. This implies that colored noise cannot break the non-classical correlation in an optical hybrid state.</P>