K. Nam - Academia.edu (original) (raw)

Papers by K. Nam

Research paper thumbnail of Determination of biodegradation potential by two culture-independent methods in PAH-contaminated soils

Biodegradation potential of PAHs in contaminated soils is determined by two culture-independent m... more Biodegradation potential of PAHs in contaminated soils is determined by two culture-independent methods and recommendations made on best approaches.

Research paper thumbnail of Progress of detailed design and supporting analysis of ITER thermal shield

The detailed design of ITER thermal shield (TS), which is planned to be procured completely by Ko... more The detailed design of ITER thermal shield (TS), which is planned to be procured completely by Korea, has been implemented since 2007. In this paper, the design and the supporting analysis are described for the critical components of the TS, the vacuum vessel TS (VVTS) outboard panel, labyrinths and VVTS supports. The wall type of VVTS outboard panel was changed from double wall to single wall, and the verification analyses were carried out for this design change. The dimensions of the labyrinths were determined and the heat load through the labyrinth was analyzed to check the design requirement. The preliminary result of the VVTS inboard and outboard supports were obtained considering the structural rigidity.

Research paper thumbnail of Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers

Methane (CH 4 ), which is one of the most abundant anthropogenic greenhouse gases, is produced fr... more Methane (CH 4 ), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH 4 is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH 4 oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH 4 (V max ) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O 2 from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O 2 and CH 4 in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH 4 slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O 2 decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N 2 and CO 2 , may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O 2 under the natural condition may overestimate the penetration of O 2 into the soil cover layer and consequently overestimate the oxidation of CH 4 .

Research paper thumbnail of Loss-minimising control scheme for induction motors

IEE Proceedings - Electric Power Applications, 2004

... in this configuration, since the speed and rotor flux are decoupled by means of nonlinear con... more ... in this configuration, since the speed and rotor flux are decoupled by means of nonlinear control. ... simplified model, the exact loss minimisation cannot be achieved, especially for high-speed operation of ... In this paper, a simplified induction motor model with iron loss is developed ...

Research paper thumbnail of New hybrid parallel active filter configuration minimising active filter size

IEE Proceedings - Electric Power Applications, 2000

Research paper thumbnail of Role of loosely bound humic substances and humin in the bioavailability of phenanthrene aged in soil

Environmental Pollution, 2002

sites for phenanthrene may reside in the humin-mineral fraction of soil, while humic and fulvic a... more sites for phenanthrene may reside in the humin-mineral fraction of soil, while humic and fulvic acids may act as a barrier, limiting the compound's bioavailabilty.

Research paper thumbnail of Papillary Thyroid Carcinoma With Thyroid-associated Orbitopathy in a Euthyroid State

Ophthalmic Plastic and Reconstructive Surgery - OPHTHALMIC PLAST RECONSTR SUR, 2007

Thyroid cancers with concurrent thyroid-associated orbitopathy (TAO) are extremely rare. The pres... more Thyroid cancers with concurrent thyroid-associated orbitopathy (TAO) are extremely rare. The present study reports 5 unusual cases of papillary thyroid microcarcinoma in patients presenting with TAO in an euthyroid state. We retrospectively reviewed the records of 5 patients (4 female, 1 male) with no known history of thyroid disease, who initially presented with TAO and were subsequently found to have thyroid cancer. TAO was diagnosed by a combination of computed tomography and clinical symptoms and signs. All patients underwent routine serologic assessment of thyroid hormones and thyroid-related autoantibodies including thyrotropin-receptor antibodies, as well as imaging studies such as neck ultrasonography or thyroid scintiscan with I. Patients presented with asymmetric proptosis (cases 1-3), ocular motility restriction (cases 1-3), and eyelid retraction (cases 1-5). None of the patients showed clinical signs of hyperthyroidism, and all returned normal thyroid function test data. Thyroid nodules were detected by neck imaging; subsequent fine-needle aspiration biopsies were performed with the cytologic result of papillary carcinoma. In no cases did ophthalmic symptoms resolve following cancer treatment (e.g., thyroidectomy and radioactive iodine therapy). All patients were positive for thyroid-binding inhibiting immunoglobulin in low titers. Although coincident occurrence is rare, patients presenting with TAO should be carefully evaluated for the possible presence of papillary microcarcinoma, which can develop in a setting of systemic autoimmunity without inducing hyperthyroidism.

Research paper thumbnail of Determination of biodegradation potential by two culture-independent methods in PAH-contaminated soils

Biodegradation potential of PAHs in contaminated soils is determined by two culture-independent m... more Biodegradation potential of PAHs in contaminated soils is determined by two culture-independent methods and recommendations made on best approaches.

Research paper thumbnail of Progress of detailed design and supporting analysis of ITER thermal shield

The detailed design of ITER thermal shield (TS), which is planned to be procured completely by Ko... more The detailed design of ITER thermal shield (TS), which is planned to be procured completely by Korea, has been implemented since 2007. In this paper, the design and the supporting analysis are described for the critical components of the TS, the vacuum vessel TS (VVTS) outboard panel, labyrinths and VVTS supports. The wall type of VVTS outboard panel was changed from double wall to single wall, and the verification analyses were carried out for this design change. The dimensions of the labyrinths were determined and the heat load through the labyrinth was analyzed to check the design requirement. The preliminary result of the VVTS inboard and outboard supports were obtained considering the structural rigidity.

Research paper thumbnail of Estimation of mass transport parameters of gases for quantifying CH4 oxidation in landfill soil covers

Methane (CH 4 ), which is one of the most abundant anthropogenic greenhouse gases, is produced fr... more Methane (CH 4 ), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH 4 is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH 4 oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH 4 (V max ) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O 2 from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O 2 and CH 4 in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH 4 slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O 2 decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N 2 and CO 2 , may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O 2 under the natural condition may overestimate the penetration of O 2 into the soil cover layer and consequently overestimate the oxidation of CH 4 .

Research paper thumbnail of Loss-minimising control scheme for induction motors

IEE Proceedings - Electric Power Applications, 2004

... in this configuration, since the speed and rotor flux are decoupled by means of nonlinear con... more ... in this configuration, since the speed and rotor flux are decoupled by means of nonlinear control. ... simplified model, the exact loss minimisation cannot be achieved, especially for high-speed operation of ... In this paper, a simplified induction motor model with iron loss is developed ...

Research paper thumbnail of New hybrid parallel active filter configuration minimising active filter size

IEE Proceedings - Electric Power Applications, 2000

Research paper thumbnail of Role of loosely bound humic substances and humin in the bioavailability of phenanthrene aged in soil

Environmental Pollution, 2002

sites for phenanthrene may reside in the humin-mineral fraction of soil, while humic and fulvic a... more sites for phenanthrene may reside in the humin-mineral fraction of soil, while humic and fulvic acids may act as a barrier, limiting the compound's bioavailabilty.

Research paper thumbnail of Papillary Thyroid Carcinoma With Thyroid-associated Orbitopathy in a Euthyroid State

Ophthalmic Plastic and Reconstructive Surgery - OPHTHALMIC PLAST RECONSTR SUR, 2007

Thyroid cancers with concurrent thyroid-associated orbitopathy (TAO) are extremely rare. The pres... more Thyroid cancers with concurrent thyroid-associated orbitopathy (TAO) are extremely rare. The present study reports 5 unusual cases of papillary thyroid microcarcinoma in patients presenting with TAO in an euthyroid state. We retrospectively reviewed the records of 5 patients (4 female, 1 male) with no known history of thyroid disease, who initially presented with TAO and were subsequently found to have thyroid cancer. TAO was diagnosed by a combination of computed tomography and clinical symptoms and signs. All patients underwent routine serologic assessment of thyroid hormones and thyroid-related autoantibodies including thyrotropin-receptor antibodies, as well as imaging studies such as neck ultrasonography or thyroid scintiscan with I. Patients presented with asymmetric proptosis (cases 1-3), ocular motility restriction (cases 1-3), and eyelid retraction (cases 1-5). None of the patients showed clinical signs of hyperthyroidism, and all returned normal thyroid function test data. Thyroid nodules were detected by neck imaging; subsequent fine-needle aspiration biopsies were performed with the cytologic result of papillary carcinoma. In no cases did ophthalmic symptoms resolve following cancer treatment (e.g., thyroidectomy and radioactive iodine therapy). All patients were positive for thyroid-binding inhibiting immunoglobulin in low titers. Although coincident occurrence is rare, patients presenting with TAO should be carefully evaluated for the possible presence of papillary microcarcinoma, which can develop in a setting of systemic autoimmunity without inducing hyperthyroidism.