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Stripping failure of punching pin in GPa-grade steels
Won, Chanhee,Lee, Seokryul,Seo, Jihoon,Park, Sung Hyuk,Yoon, Jonghun Springer-Verlag 2018 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TE Vol.94 No.1
<P>GPa-grade steels which possess the ultimate tensile strength over 1000 MPa and higher elongation have been thoroughly researched to replace conventional high-strength steels in automobile industry to enhance fuel efficiency without sacrificing crashworthiness. However, high strength of GPa-grade steel does not only induce punching pin buckling due to high contact pressure, but also abrasive wear on the mold surface due to the unstable contact that results from the large amount of springback, which tend to impede widespread usage of GPa-grade steels. In this research, design criteria for an optimal aspect ratio of the punching pin preventing buckling failure has been proposed by linking with experimental and numerical analyses, which is validated with the analytic solutions. Furthermore, in order to prevent stripping failure, it is highly recommended that one of the main factors, a blank holder force (BHF), over 1.5 MPa has to be maintained during the withdrawal process to minimize the effect of springback in stamped panels applying GPa-grade steel, which is able to extend the tool life of the side punching pin about 100,000 cycles.</P>
Seo, Hwi Won,Park, Su-Jin,Park, Changhoon,Chae, Chanhee Elsevier 2014 Vaccine Vol.32 No.21
The objective of this study was to determine the effects of porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae vaccinations on disease severity in an experimental PCV2-M. hyopneumoniae dual challenge model. Vaccine effectiveness was evaluated using microbiological (PCV2 viremia and M. hyopneumoniae nasal shedding), immunological (neutralizing antibodies and interferon-gamma-secreting cells), and pathological (gross lung lesions, histopathologic pulmonary and lymphoid lesions, and the presence of PCV2 antigen and M. hyopneumoniae DNA within the lesions) evaluations. Although M. hyopneumoniae potentiates the severity of PCV2-associated lesions and lesion-associated PCV2 antigen in dually challenged pigs, vaccination against M. hyopneumoniae alone did not reduce PCV2 viremia, PCV2-induced lesions, or PCV2 antigen in dually challenged pigs. In addition, vaccination against PCV2 did not reduce the nasal shedding of M. hyopneumoniae, the M. hyopneumoniae-induced pulmonary lesions or the lesion-associated M. hyopneumoniae DNA in dually challenged pigs. Dual challenge with PCV2 and M. hyopneumoniae did not interfere with the induction of active immunity induced by a previous single vaccination for either PCV2 or M. hyopneumoniae. The results of this study demonstrated that (i) vaccination against M. hyopneumoniae alone did not decrease the potentiation of PCV2-induced lesions by M. hyopneumoniae and (ii) vaccination against PCV2 alone decreased the potentiation of PCV2-induced lesions by M. hyopneumoniae in dually challenged pigs. (C) 2014 Elsevier Ltd. All rights reserved.
Seo, Hwi Won,Han, Kiwon,Oh, Yeonsu,Kang, Ikjae,Park, Changhoon,Joo, Hye Eun,Kim, Sung-Hoon,Lee, Bog-Hieu,Chae, Chanhee Canadian Veterinary Medical Association = Associat 2014 Canadian journal of veterinary research Vol.78 No.3
<P>The objective of the present study was to evaluate polyclonal- and monoclonal-antibody-based immunohistochemical (IHC) tests for the detection of 2 genotypes of Porcine circovirus type 2 (PCV2), a and b, in formalin-fixed, paraffin-embedded lymph-node tissue from pigs with experimental or natural postweaning multisystemic wasting syndrome and to compare the IHC results with those of in-situ hybridization (ISH) assays. The ISH assays proved more sensitive than the IHC tests for the detection of PCV2a and PCV2b. According to these findings, polyclonal-antibody-based IHC testing is the most practical routine diagnostic method for the detection of PCV2 regardless of genotype because IHC testing is less technically complex than ISH testing. However, ISH assays are useful to differentiate between PCV2a and PCV2b in surveillance programs for the monitoring of PCV2 in swine herds.</P>
Seo, Hwi Won,Han, Kiwon,Kim, Duyeol,Oh, Yeonsu,Kang, Ikjae,Park, Changhoon,Jang, Hyun,Chae, Chanhee American Society for Microbiology 2011 Clinical and vaccine immunology Vol.18 No.7
<B>ABSTRACT</B><P>The objective of the present study was to determine the effect of an inactivated porcine circovirus type 2 (PCV2) vaccine on PCV2b virus shedding in the semen of experimentally infected boars by measuring the immunological response and the PCV2b DNA load in blood and semen. Twelve boars were randomly divided into three groups. The boars in group 1 (<I>n</I>= 4) were immunized with an inactivated PCV2 vaccine and were challenged with PCV2b. The boars in group 2 (<I>n</I>= 4) were only challenged with PCV2b. The boars in group 3 (<I>n</I>= 4) served as negative controls. The number of PCV2 genome copies of PCV2 in the serum and semen were significantly lower in vaccinated challenged boars than in nonvaccinated challenged boars at 7, 10, 14, 21, 32, 35, 42, 49, and 60 days postinoculation. The number of PCV2b genomes in the semen correlated with the number of PCV2b genomes in the blood in both vaccinated challenged (<I>R</I>= 0.714) and nonvaccinated challenged (<I>R</I>= 0.861) boars. The results of the present study demonstrate that the inactivated PCV2 vaccine significantly decreases the amount of PCV2b DNA shedding in semen from vaccinated boars after experimental infection with PCV2b.</P>
Seo, Hwi Won,Park, Changhoon,Han, Kiwon,Chae, Chanhee BioMed Central 2014 Veterinary research Vol.45 No.-
<P>The objective of this study was to evaluate the effect of porcine circovirus type 2 (PCV2) vaccines on PCV2-viremic and -seropositive piglets born from naturally PCV2-infected sows against postnatal PCV2 challenge. The experimental design was aimed at mimicking commercial swine rearing conditions to evaluate the response of the PCV2 vaccine on PCV2-viremic and -seropositive piglets after experimental PCV2 challenge. PCV2a (or 2b)-viremic piglets received a PCV2 vaccine at 21 days of age followed by a PCV2b (or 2a) challenge at 49 days of age (28 days post vaccination). The PCV2 vaccines elicited a high level of humoral (as measured by immunoperoxidase monolayer assay and neutralizing antibody titers) and cellular (as measured by the frequency of PCV2-specific interferon-γ-secreting cells) immune response in the PCV2-viremic piglets after vaccination even in the presence of maternally derived antibodies (MDA). The initial infection of PCV2 in the pigs was not affected by PCV2 vaccination, however the challenging PCV2 was reduced by PCV2 vaccination on PCV2-viremic pigs. The results from this study demonstrate that the PCV2 vaccine used in this study is effective at reducing PCV2 viremia and lymphoid PCV2 DNA, even for PCV2-viremic pigs with passively acquired MDA at the time of vaccination.</P>
Characterization of glass viscosity with parallel plate and rotational viscometry
Song, Youngnam,Won, Chanhee,Kang, Seong-hoon,Lee, Howon,Park, Sung-Jun,Park, Sung Hyuk,Yoon, Jonghun Elsevier 2018 Journal of non-crystalline solids Vol.486 No.-
<P><B>Abstract</B></P> <P>Glass materials have been applied as insulators during hot extrusion of titanium- and nickel-based alloys to reduce the friction and thermal conduction in the Ugine-Séjournet process. In this research, parallel plate viscometry (PPV) and rotational viscometry (RV) tests were carried out to characterize the viscosity of glass materials such as lead-borate, potassium-lead-silicate, and potassium-sodium-lead-silicate, quantitatively. Herein, we propose a new equation that can be used to predict an extensive range of viscosities from the softening to the melting point. This equation demonstrates more accurate predictions compared with the conventional Vogel–Fulcher–Tamman (VFT), the Avramov&Milchev (AM) and the Mauro-Yue-Ellison-Gupta-Allan (MYEGA) equations.</P>