When decommissioning of nuclear facilities happens, large amounts of radioactive wastes are released. Because costs of nuclear decommissioning are enormous, effective and economical decontamination technologies are needed to remove radioactive wastes. During NPP operation, corrosion product called Chalk River Unidentified Deposits (CRUD) is generated. CRUD is an accumulation of substances and corrosion products consisting of dissolved ions or solid particles such as Ni, Fe, and Co on the surface of the NPP fuel rod coating. CRUD is slowly eroded by the circulation of hot pressurized water and later deposits on the fuel rod cladding or external housing, thereby reducing heat production by the nuclear fuel. Decontamination of radiologically contaminated metals must be performed before disposal, and several methods for decontaminating CRUD are being studied in many countries. Decontamination technology is an alternative to reducing human body covering and reducing radioactive waste disposal costs, and much research and development has been conducted to date. Currently, the importance of decontamination is emerging as the amount of waste stored in radioactive waste storage is close to saturation, and the amount of radioactive waste generated must be minimized through active decontamination. In this study, a preliminary study was conducted on the removal of CRUD by multiple membrane in an electro-kinetic process using an electrochemicalbased decontamination method. Preliminary research to develop a technology to electrochemically remove CRUD by using a self-produced electrochemical cell to check the pH change over time of the CRUD cell according to voltage, electrolyte, membrane and pH change.

In this study, gold nanoparticles (AuNPs) were synthesised using green chemistry to decorate multi-walled carbon nanotubes (MWCNTs) made from walnut shells transmission electron microscopy, field-emission scanning electron microscopy (FESEM), atomic force microscopy and fourier transforms infrared spectroscopy were used to diagnose MWCNTs and AuNPs. MWCNT-COOAu, MWCNT-COO and MWCNT-Au were diagnosed by Raman, energy dispersive X-ray analysis and FESEM. The effect of AuNPs, MWCNT-COO, MWCNT-COOAu and MWCNT-Au on pure and serum alkaline phosphatase (ALP) enzyme activity was studied in vitro using the enzyme-substrate 4-nitrophenyl disodium orthophosphate. For pure enzymes, Vmax slightly increased as the concentration of MWCNT-Au, MWCNT-COOAu and MWCNTCOO increased, whereas the Vmax values decreased as the concentration of AuNPs increased. The inhibition type for all NPs varied. For serum ALP enzyme, the Vmax values for Au-based NPs decreased as the concentration of NPs increased. The Vmax values exceeded the standard value at the concentrations of 25, 50 and 75 ppm for MWCNT-Au and MWCNT-COOAu, whereas the Vmax values increased over the standard value for all concentrations of AuNPs.

High voltage impulse (HVI) has been gained attention as an alternative technique that could control the CaCO3 scale problems encountered in water main, pipe, cooling tower and heat exchanger vessels. The aim of this study was to investigate the effect of electric field (E) and contact time (t) of HVI on reduction of Ca2+ concentration at two different temperatures of 25℃ and 60℃. A kinetic model on the effect of E and t was investigated too. As the E and t increased, the Ca2+ concentration decreased more than that of the control (= no HVI). The Ca2+ concentration decreased up to 81% at 15 kV/cm at 60℃, which was nearly 2 times greater than the control. With these experimental data-set of reduction of Ca2+ concentration under different E and t, the kinetic model was developed. The relationship between E and t required to reduce the concentration of Ca2+ by 30% was modeled at each temperature. The empirical model equations were; E0.83· t = 60.3 at 25℃ and E0.08· t = 1.1 at 60℃. These equations state the products of En and t is always constant, which means that the required contact time can be reduced in accordance with the increment of E and vice versa.

덕트에 설치되는 오리피스는 압력과 유량 제어용으로 많이 활용되고 있다. 선박의 거주 구역에 통풍 덕트는 환기와 배기를 위해 설치되며 및 선박의 설계 및 건조 후 검사는 공기 유속과 유량 그리고 소음 기준에 대해 수행된다. 이 연구에서는 선박의 선실 별 유량분배에 중요한 요소인 T-분지관을 대상 으로 오리피스를 적용한 경우 난류운동에너지 분포를 고찰하였다.

Isotactic polyacrylonitrile (PAN) with triad isotacticity of 0.53, which was determined by 13C NMR, using dialkylmagnesium as an initiator, was successfully synthesized. Isothermal treatment of iso-PAN was conducted in air at 200, 220, 250 and 280℃. Structural evolutions and chemical changes were studied with Fourier transformation infrared and wide-angle X-ray diffraction during stabilization. A new parameter CNF=I2240cm-1/ (I1595cm-1+f*I1595cm-1) was defined to evaluate residual nitrile groups. Crystallinity and crystal size were calculated with X-ray diffraction dates. The results indicated that the nitrile groups had partly converted into a ladder structure as stabilization proceeded. The rate of reaction increased with treatment temperature; crystallinity and crystal size decreased proportionally to pyrolysis temperature. The iso-conversional method coupled with the Kissinger and Flynn-Wall-Ozawa methods were used to determine kinetic parameters via differential scanning calorimetry analysis with different heating rates. The active energy of the reaction was 171.1 and 169.1 kJ/mol, calculated with the two methods respectively and implied the sensitivity of the reaction with temperature.

The aim of the present study was to investigate age-related differences in stepping behavior in response to sensory perturbations of postural balance. The participants for this study were 2 healthy elderly adults (mean age=76.0) and 2 younger adults (mean age=25.5). Subjects were asked to step over a 10 cm high obstacle at self-paced speed with the right limb to land on the primary target (normal step length) that is 10 cm in diameter. However, if, during movement, the light was illuminated, then the subject had to step on the secondary target (long step length). It was planned that the onset of the light would be prior to peak Fx of swing limb, between swing peak Fx and swing toe-off, and after swing toe-off. In the younger adults these secondary visual cues were provided at mean times of 240 ms (standard deviation (SD)=11), 402 ms (SD=13), and 476 ms (SD=88) following the movement onset. Corresponding mean times for the healthy elderly were 150 ms (SD=67), 352 ms (SD=39), and 562 ms (SD=115). Results showed great changes in both group and visual cue condition in Fx ground reaction forces and temporal events following the swing toe-off. Swing limb acceleration force (Fx) and stance peak Fx1 was much greater in the young adults compared to the older adults. Both young and older adults increased stance peak Fx2 in the visual cue condition compared to normal stepping. There was no difference in stance peak Fx2 between the visual cue conditions in both groups. Similarly, the time to stance peak Fx2 was much longer for the visual cue condition than for the normal stepping. It was not different between the visual cue conditions in the young adults, but in the elderly mid and late cue was much greater than early cue. In addition, time to stance peak Fx2 and swing and stance time were much longer in the older adults compared to the young adults for the visual cue conditions. These results suggest that unlike young adults, elderly adults did not flexibly modify their responses to unexpected changes in step length while stepping over obstacles.

염화철(Ferrous Choloride) 증기의 고온 수소환원 반응을 통한 미립질 철분말의 생성속도에 대한 이론적인 해석돠 실험을 수행하였다. 철분말의 생성기구는 염화철이 증발하여 생성된 증기와 운반가스인 알곤을 혼합하여 반응부로 유입시키고 수소에 의한 고온환원반을을 통하여 철분말과 함께 부산물인 염화수소(HCI) 가스를 얻게 된다. 생성된 반응부 후미에 설치한 유기용매 포집기를 이용하여 회수하였으며, 염화수소는 가성소다 수용액에 흡수시키고 이를 적정함으로써 초기 반응물인 염화철의 전환율을 계산하였다. 반응속도식의 반응물에 대하여 1차반응(1st-order reaction)이고 염화철 증가와 운반체인 알곤가스가 평형상태일 때의 속도상수는 k=7,879exp(-53,840/RT)dm3/mole.sec으로 표시되며, 이때의 활성화에너지는 53.84kJ/mole이었다. 철분말의 TEM 사진에 의하면 입도범위는 0.1~1.0μm이며, 반응온도 및 가스유량에는 크게 영향을 받지 않는것으로 나타났다.

The re-emission of mercury (Hg), as a consequence of the formation and dissociation of the unstable complex HgSO3, is a problem encountered in flue gas desulphurization (FGD) treatment in coal-fired power plants. A model following a pseudo-second-order rate law for Hg2+ reduction was derived as a function of [SO32-], [H+] and temperature and fitted with experimentally obtained data to generate kinetic rate values of (0.120 ± 0.04, 0.847 ± 0.07, 1.35 ± 0.4) mM-1 for 40°, 60°, and 75℃, respectively. The reduction of Hg2+ increases with a temperature increase but shows an inverse relationship with proton concentration. Plotting the model-fitted kinetic rate constants yields ΔH = 61.7 ± 1.82 kJ mol-1, which is in good agreement with literature values for the formation of Hg0 by SO32-. The model could be used to better understand the overall Hg2+ re-emission by SO32- happening in aquatic systems such as FGD wastewaters.

The chemical kinetics of the steam reforming of the pyrolysis oil of polypropylene (PP) over a ruthenium-based catalyst has been examined as a function of pyrolysis oil and steam partial pressures at various temperatures. The activation energy of steam reforming over Ru/Al2O3 catalyst is 136 kJ/mol, and the reaction orders of pyrolysis oil and steam are 0.42 and 0.24, respectively. Fitting the experimental data to the Langmuir?Hinshelwood expression shows that the steamreforming reaction probably proceeds via the dissociative adsorption of pyrolysis oil and steam on two different sites.

In this study, activation energy of lignite, RPF and a sample mixed both of them was obtained through kinetics characteristics analysis in pyrolysis in order to identify the applicability of RPF as an assistant fuel. TGA (Thermogravimetric analysis) was conducted with follow experimental conditions; in a nitrogen atmosphere, gas flow rate of 20 ml/min, heating rate of 5 ~ 50oC/min, and maximum hottest temperature of 800oC. As a result of TGA, it showed that pyrolysis of samples mixed with 20% and 10% of RPF were more stable than other mixed ratio, and 20% of RPF was the most similar with lignite in activation energy.

본 연구에서는 전투시스템의 생존성을 향상하기 위한 기술개발의 일환으로서 전투시스템이 외부 위협탄에 의한 충격을 받았을 경우, 전투시스템의 순간화재 발생에 따른 취약성을 분석하는 기법을 개발하고자 전산모사 해석방법을 이용하여 전투시스템의 순간화재 발생 가능성에 대해서 고찰하였다. 전투시스템의 유형은 임의 모형의 전차를 대상으로 선정하였으며, 전차의 구성요소들 가운데 외부 위협탄에 의해 순간화재가 발생할 수 있는 critical component로서는 고폭탄(추진제 포함)과 연료탱크 가운데 연료탱크만을 대상으로 선정하였다. 연료탱크에 주입된 연료는 휘발유, 경유, 등유 세 가지를 선정하고 관련 물성값을 이용하였다. 외부 위협탄은 1,475 m/s의 탄속을 갖는 운동에너지탄 type A와 1,560 m/s의 탄속을 갖는 운동에너지탄 type B로 가정하여 전산모사 해석을 수행하였다. 해석 프로그램은 Autodyn 프로그램을 사용하였고, Shock model을 적용하여 Lagrange process를 사용해서 1㎜ 간격의 계산격자로 계산을 수행한 결과, 평균 2시간 정도(CPU：Intel Core2 Duo, Quad 2.93GHz, RAM：1.75GB)가 소요되었다. 장갑의 두께별 관통된 탄두로부터 연료로의 열전달에 따른 온도값들을 이용하여 연료의 발화온도와 비교하여 순간화재의 발생 가능성을 고찰한 결과, 모든 탄두의 온도가 각각의 연료들의 발화온도보다 낮기 때문에 순간화재가 발생하지 않는 것으로 생각된다.

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k1 was 0.07∼0.17 ℓ/㎎·hr and maximum exchange quantity q0 was 27.75∼31.81 ㎎/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 ㎎/ℓ nitrate-contained wastewater of 10,000 gallons per day to 2 ㎎/ℓ , total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.

A kinetic study for anion exchange was performed for commercially available Cl- type anion exchange resin in use to remove nitrate in water. The obtained results from the batch reactor were applied to the Langmuir and Freundlich models. The constants for Langmuir model were qmax=29.82 and b=0.202, and for Freundlich model were K=5.509 and n=1.772. Langmuir model showed better fit than Frendlich model for the experimental results. Ion exchange reaction rate was also calculated and the approximate first-order reaction, rate constant k1 was 0.16 L/㎎·hr. Effective diffusion coefficient was obtained in the range from 9.67×10 exp (-8) to 1.67×10 exp (-6) ㎠/sec for initial concentration change, and from 6.09×10 exp (-7) to 3.98×10 exp (-6) ㎠/sec for reaction temperature change. Activation energy during the diffusion was calculated as 36 ㎉/㏖.