Evaluation of sintering behavior of ash particles from coal and rice straw using optical heating stage microscope at high temperature fouling conditions

Namkung, H.,Hu, X.,Kim, H.T.,Wang, F.,Yu, G. Elsevier Scientific Pub. Co 2016 Fuel processing technology Vol.149 No.-

Ash adhesion and elimination in the gasification process is one of the main challenges in maintaining a continuous operation of the plant. The properties of ash adhesion and elimination are mainly related to particle sintering behavior. Different sintering behaviors of Shenhua coal ash (SCA) and rice straw ash (RSA) below the inherent initial deformation temperature (IDT) were observed by using optical heating stage microscope (OHSM) under CO<SUB>2</SUB> and Ar environments. The particle interaction of the RSA, the IDT of which was lower than that of SCA, was higher than that of SCA at the same temperature. Adding RSA to the SCA was an effective means of increasing particle sintering of SCA. The sintering reaction rate of ash particles highly increased at beginning of sintering stage. The effects of inorganic chemicals in the sintering process were evaluated by using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and typical fouling indices. The Ca and K were predominant contributors to the increase in sintering. The degree of sintering through the experiments was compared to a modified Frenkel sintering model, which accurately simulated the sintering tendency under isothermal conditions.

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.

Bibliographic Check list of Korean Spiders (Arachnida: Araneae) ver. 2010

NamKung, Joon,Yoo, Jung-Sun,Lee, Sue-Yeon,Lee, Joon-Ho,Paek, Woon-Kee,Kim, Seung-Tae national science museum of korea 2009 Journal of Korean nature Vol.2 No.3

A bibliographic checklist of Korean spiders from the 1956 checklist by Paik and Kim is presented, with a complete bibliography of the relevant Korean araneological literature. For the period of 1907-2009, a total of 507 publications on the spiders were extensively searched and records of taxonomic descriptions were included. Records are listed only from the locations within the present borders of South Korea. A total of 681 species of 258 genera belonging to 46 families were confirmed to exist in Korea. Twenty species, namely Pholcus pojeonensis, Pholcus kwangkyosanensis, Pholcus parkyeonensis, Dysdera crocata, Miagrammopes coreensis, Parasteatoda culicivora, Spheropistha melanosoma, Bathyphantes major, Araneus viperifer, Larinia onoi, Neoscona holmi, Pardosa isago, Pardosa monticola, Trochosa spinipalpis, Anahita samplexa, Cheiracanthium lascivum, Cheiracanthium eutittha, Clubiona japonica, Rhene myunghwani, and Sitticus sinensis, whose distribution or existence within the Korean border were uncertain and did not meet the requirements for valid records were excluded from the present list following critical validation. Sixteen species, namely, Clubiona bakurovi, Clubiona corrugata, Clubiona hummeli, Clubiona komissarovi, Clubiona kulczynskii, Clubiona microsapporensis, Clubiona orientalis, Clubiona paralena, Clubiona propinqua, Clubiona proszynskii, Clubiona sapporensis, Mendoza nobilis, Pseudicius koreanus, Sibianor nigriculus, Sitticus penicilloides, and Yllenus coreanus, which have been described or reported to exist in North Korea were listed separately from the present list. From the zoogeographical distribution, Korean spider fauna was found to be influenced by northern species, including 35 Holarctic and 67 Palearctic species, which account for 14.9% of the total number of species. Korean endemic species include 131 species, which account for 19.2% of the total number. Among neighboring countries, Korean spiders are most similar to those found in Japan. This list (ver. 2010) will be revised periodically after this version.

Peripheral Serotonin: a New Player in Systemic Energy Homeostasis

Namkung, Jun,Kim, Hail,Park, Sangkyu Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.12

Whole body energy balance is achieved through the coordinated regulation of energy intake and energy expenditure in various tissues including liver, muscle and adipose tissues. A positive energy imbalance by excessive energy intake or insufficient energy expenditure results in obesity and related metabolic diseases. Although there have been many obesity treatment trials aimed at the reduction of energy intake, these strategies have achieved only limited success because of their associated adverse effects. An ancient neurotransmitter, serotonin is among those traditional pharmacological targets for anti-obesity treatment because it exhibits strong anorectic effect in the brain. However, recent studies suggest the new functions of peripheral serotonin in energy homeostasis ranging from the endocrine regulation by gut-derived serotonin to the autocrine/paracrine regulation by adipocyte-derived serotonin. Here, we discuss the role of serotonin in the regulation of energy homeostasis and introduce peripheral serotonin as a possible target for anti-obesity treatment.

Blending effect of sewage sludge and woody biomass into coal on combustion and ash agglomeration behavior

Namkung, Hueon,Lee, Young-Joo,Park, Ju-Hyoung,Song, Gyu-Seob,Choi, Jong Won,Choi, Young-Chan,Park, Se-Joon,Kim, Joeng-Geun Elsevier 2018 Fuel Vol.225 No.-

<P><B>Abstract</B></P> <P>The co-combustion of sewage sludge and woody biomass is a key issue in coal power plants. Different combustion and ash behaviors of sewage sludge and woody biomass cause unpredictable operating concerns. In this study, the combustion and ash agglomeration behavior of blended fuel of sewage sludge and woody biomass (BSW) were investigated while coal co-combusted with it. Thermogravimetric analysis (TGA) revealed that adding a high amount of BSW into the coal lowered volatilization, ignition, and burn-out temperature. The char combustion reactivity of coal differed from that of BSW. The shrinking core model (SCM) and volumetric reaction model (VRM) were used to fit the char combustion reactivity of coal and BSW. In the case of ash agglomeration behavior, BSW addition led to increasing particle agglomeration at fouling temperatures. In particular, phosphorus composition influenced particle growth, which was verified using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) analysis. Furthermore, the ash mixture ratio of BSW and coal changed the intensity of the phosphorus-bearing mineral phase from X-ray diffraction (XRD) analysis, and finally influenced the melting temperature of the ash.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The combustion and ash agglomeration characteristics of coal and BSW mixture were investigated. </LI> <LI> Addition of BSW into the coal lowered the combustion temperature profiles during non-isothermal heating conditions. </LI> <LI> Carbon and reagent gas reaction occurred on exterior and interior of the particle during char combustion. </LI> <LI> BSW containing high phosphorus contents made a high agglomeration tendency and low melting mineral phase. </LI> </UL> </P>

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>

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.

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>

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>