• Nuclear Engineering and Technology
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• 제48권3호
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• pp.727-732
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• 2016

A simple and rapid spectrophotometric method has been developed to enable the determination of plutonium concentration in an irradiated fuel solution in the presence of all fission products. An excess of ceric ammonium nitrate solution was employed to oxidize all the valence states of plutonium to +6 oxidation state. Interference due to the presence of fission products such as ruthenium and zirconium, and corrosion products such as iron in the envisaged concentration range, as in the irradiated fuel solution, was studied in the determination of plutonium concentration by the direct spectrophotometric method. The stability of plutonium in +6 oxidation state was monitored under experimental conditions as a function of time. Results obtained are reproducible, and this method is applicable to radioactive samples resulting before the solvent extraction process during the reprocessing of fast reactor spent fuel. An analysis of the concentration of plutonium shows a relative standard deviation of <1.2% in standard as well as in simulated conditions. This reflects the fast reactor fuel composition with respect to uranium, plutonium, fission products such as ruthenium and zirconium, and corrosion products such as iron.

• 품질경영학회지
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• 제22권2호
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• pp.41-50
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• 1994

Consider a canning process where cans are filled with an expensive ingredient. Cans weighting above the specified limit are sold in a regular market for a fixed price, and underfilled cans are emptied and refilled at the expense of a reprocessing cost. In this paper, the effect of measurement error on the determination of the optimal process mean for a canning process is examined. It is assumed that the quantity X of ingredient in a can is normally distributed with unknown mean and known variance, and the observed value Y of X is also normally distributed with known mean and variance. A profit model is constructed which involves selling price. cost of ingredients, reprocessing cost. and cost from an accepted nonconforming can, and methods of finding the optimal process mean and the cutoff value on Y are presented. It is shown that the optimal process mean increases. and the expected profit decreases when the measurement error is relatively large in comparison to the process variance.

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1727-1732
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• 2017

Pyroprocessing is an alternative method of reprocessing spent fuel, usually involving the dissolving spent fuel in a molten salt media. The National Nuclear Laboratory designed, built, and commissioned a molten salt dynamics rig to investigate the transfer characteristics of molten lithium chloride-potassium chloride eutectic salt. The efficacy and flow characteristics of a high-temperature centrifugal pump and argon gas lift were obtained for pumping the molten salt at temperatures up to $500^{\circ}C$. The rig design proved suitable on an industrial scale and transfer methods appropriate for use in future molten salt systems. Corrosion within the rig was managed, and melting techniques were optimized to reduce stresses on the rig. The results obtained improve the understanding of molten salt transport dynamics, materials, and engineering design issues and support the industrialization of molten salts pyroprocessing.

• Nuclear Engineering and Technology
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• 제52권1호
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• pp.109-114
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• 2020

This work presents the results of laboratory scale tests of the CARBOFLUOREX (CARBOnate FLUORide EXtraction) process - a novel technology for the recovery of U and Pu from the solid fluorides residue (fluorination ash) of Fluoride Volatility Method (FVM) reprocessing of spent nuclear fuel (SNF). To study the oxidative leaching of U from the fluorination ash (FA) by Na₂CO₃ or Na₂CO₃-H₂O₂ solutions followed by solvent extraction by methyltrioctylammonium carbonate in toluene and purification of U from the fission products (FPs) impurities we used a surrogate of FA consisting of UF₄ or UO₂F₂, and FPs fluorides with stable isotopes of Ce, Zr, Sr, Ba, Cs, Fe, Cr, Ni, La, Nd, Pr, Sm. Purification factors of U from impurities at the solvent extraction refining stage reached the values of 10⁴-10⁵, and up to 10⁶ upon the completion of the processing cycle. Obtained results showed a high efficiency of the CARBOFLUOREX process for recovery and separating of U from FPs contained in FA, which allows completing of the FVM cycle with recovery of U and Pu from hardly processed FA.

• 비파괴검사학회지
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• 제22권6호
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• pp.609-620
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• 2002

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. However, the ultimate temperature rise and the rate of temperature rise is related to the nature of the material, conditions of the test and also to the deformation behaviour of the material during loading. The recent advances in infrared sensors and image/data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been used to characterise the tensile deformation in AISI type 316 nuclear grade stainless steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which the point and time of strain localization could be identified. The technique makes it possible to visualise the region of deformation and failure and also predict the exact region of fracture in advance. The effect of thermal gradients on plastic flow in the case of interrupted straining revealed that the interruption of strain and restraining at a lower strain rate not only delays the growth of the temperature gradient, but the temperature rise per unit strain decreases. The technique is a potential NDE tool that can be used for on-line detection of thermal gradients developed during extrusion and metal forming process which can be used for ensuring uniform distribution of plastic strain.

• Elastomers and Composites
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• 제37권4호
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• pp.234-243
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• 2002

A general scheme of a rubber structure is proposed. Using the thermomechanical method(TMA), some changes in the molecular and topological structures for uncured and cured, and unfilled and filled rubbers during processing are shown. In our investigations as region it is understood a complex structure, which is expressed at the thermomechanical curve(TMC) as a zone differed from others in thermal expansion properties. This zone is between the noticed temperatures of relaxation transitions, usually on the level like those determined by DMTA at 1Hz. These regions, which shares, are not stable, and differ in molecular-weight distribution(MWD) of chain fragments between the junctions. Differences in dynamics of the formation of the molecular and topological structures of a vulcanizate are dependent on the rubber formulation, mixing technology and curing time. Some of characteristics of these regions correlate with mechanical properties of vulcanizates what is shown for NR rubbers containing ENR or CPE as a polymeric additive. It is well known that the state of order influences diffusivity of low-molecular substances into the polymer matrix. Because of this, the two topological amorphous regions should influence the distribution of the ingredients and resulting in rubber compounds' heterogeneity, and related properties of cured rubber. Investigation of this problem is expected to be, in the future, one of the essential factors in determining further improvement of polymeric materials properties by compounding with additives and in reprocessing of rubber scrap.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.419-425
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• 2024

The purpose of this study is to improve the concentration of U(VI) in carbonate solution reasonably, which to improve the application potential of the alkaline reprocessing processes. The dissolution behavior of U₃O₈ in carbonate peroxide solutions was investigated under different conditions, including pH, carbonate concentration, and solid-liquid ratio. The results showed that the dissolution rate of U₃O₈ increased with the increase of pH from 8 to 11 in the mixed carbonate solution containing 0.5 mol/L H₂O₂. The role of carbonate ions in the dissolution of U₃O₈ was further elucidated by observing the dissolution of UO₄⋅4H₂O in carbonate solutions. Furthermore, the concentration of U(VI) in 3 mol/L Na₂CO₃ solution was successfully increased to 350 g/L under ultrasonic-assisted conditions at 60 ℃ and a solid-liquid ratio at 1/2 g/mL. Meanwhile, it is suggested that increasing the concentration of carbonate ions can improve the stability of the dissolved solution containing uranyl peroxycarbonate complex.

• 생물정신의학
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• 제17권2호
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• pp.94-102
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• 2010

Objectives : Eye movement desensitization and reprocessing(EMDR) is a novel, time-limited psychotherapy originally developed for treatment of psychological trauma. The effectiveness of this therapy has been validated only for posttraumatic stress disorder ; however, EMDR is often applied to other psychiatric illnesses, including other anxiety disorders and depression. This pilot study tested the efficacy of EMDR added to the routine treatment for individuals with acute stage schizophrenia. Methods : This study was conducted in the acute psychiatric care unit of a university-affiliated training hospital. Inpatients diagnosed with schizophrenia were randomly assigned to either three sessions of EMDR, three sessions of progressive muscle relaxation(PMR) therapy, or only treatment as usual(TAU). All the participants received concurrent typical treatments(TAU), including psychotropic medication, individual supportive psychotherapy and group activities in the psychiatric ward. The Positive and Negative Syndrome Scale(PANSS), the Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale were administered by a clinical psychologist who was blinded to the patients' group assignment. Results : Forty-five patients enrolled and forty patients(89%) completed the post-treatment evaluation. There were no between-group differences in the withdrawal rates of patients during the treatment or at the three-month follow-up session. All three groups improved significantly across each of the symptomatic domains including schizophrenia, anxiety, and depressive symptoms. However, a repeated measures ANOVA revealed no significant differences among the groups over time. Effect size for change in total PANSS scores was also similar across treatment conditions, but effect size for negative symptoms was large for EMDR(0.60 for EMDR, 0.39 for PMR and 0.21 for TAU only). Conclusion : These findings supported the use of EMDR in treating the acute stage of schizophrenia but the results failed to confirm the effectiveness of the treatment over the two control conditions in three sessions. Further studies with longer courses of treatment, more focused target dimensions of treatment, and a sample of outpatients are necessary.

• 보존과학회지
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• 제35권2호
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• pp.177-186
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• 2019

국내 목조문화재 흰개미 방제법 중 하나인 토양처리법에 적용되는 약제는 우천이나 지중의 수분 거동에 의해 방의 효력 저하가 진행되어 재처리가 요구되지만 현재 해당 기준 및 평가 방안은 전무한 실정이다. 이에 따라 약제의 방의 효력 평가 및 재처리 기간 산정을 위한 기초 실내 평가 방안을 제시하였다. 먼저 약제 방의력 평가를 위해 흰개미에 대한 기피성 및 접촉 독성을 실시하였다. 그 결과, 이번 실험에 사용된 약제는 비기피성이며, 접촉에 의한 사멸이 확인되었다. 이후 모의 강우 실험과 토양 관통 시험을 통해 토양 내 약제의 방의 효력 임계점을 산정하는 지속성 평가를 실시하였고 해당 자료를 기상 자료와 비교하여 재처리 기간을 산정하였다. 지속성 평가 결과, 약 160~170 mm 이상의 지속적인 수분 노출 이후에는 약제 처리 토양에 대한 흰개미의 천공이 확인되었다. 해당 결과를 최근 5년간 기상 자료와 비교한 결과, 본 실험에서 사용된 농도의 약제는 우리나라 장마철과 여름철 집중호우 기간이 지난 9월 이후 처리할 경우 약 1년 정도 방의 효력이 유지될 것으로 예상된다. 본 연구는 향후 국내 흰개미 방제를 위한 토양처리용 약제의 선정 매뉴얼 작성과 재처리 기간 산정을 위한 기초자료를 제공 할 수 있을 것으로 기대된다.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2005년도 춘계학술대회
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• pp.7-17
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• 2005

Consider a stuffing process where sausage-casings are filled with sausage-kneading. One of the most important factors in the stuffing process is weights of stuffed sausages. Sausages weighting above the specified limit are sold in a regular market price for a fixed price, and underfilled sausages are reworked at the expense of reprocessing cost. In this paper, the sausage stuffing process is inspected for improving productivity and quality levels. Several statistical process control tools are suggested by using real data obtained from a Korean Vienna sausage company.