• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.208-212
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• 2022

In this paper, we report the effects of temperature on the deterioration of graphite-based negative electrodes during the longterm cycling of lithium-ion batteries (LIBs). After cycling 75 Ah pouch-type LIB full cells at temperatures of 45℃ (45-Cell) and 25℃ (25-Cell) until their end of life, we expected to observe changes in the negative electrode according to the temperature. The thickness of the negative electrode of the cell was greater after cycling; that of the electrode of 45-Cell (144 ㎛) was greater than that of the electrode of 25-Cell (109 ㎛). Cross-sectional scanning electron microscopy analysis confirmed that by-products caused this increase in the thickness of the negative electrode. The by-products that formed on the surface of the negative electrode during cycling increased the surface resistance and decreased the electrical conductivity. Voltage profiles showed that the negative electrode of 25-Cell exhibited an 84.7% retention of the initial capacity, whereas that of 45-Cell showed only a 70.3% retention. The results of this study are expected to be relevant to future analyses of the deterioration characteristics of the negative electrode and battery deterioration mechanisms, and are also expected to provide basic data for advanced battery design.

• Industrial Engineering and Management Systems
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• v.15 no.4
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• pp.364-373
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• 2016

Disassembly is one of the important activities in treating with the product at the End of Life time (EOL). Disassembly is defined as a systematic technique in dividing the products into its constituent elements, segments, sub-assemblies, and other groups. We concern with a Fuzzy Disassembly Line Balancing Problem (FDLBP) with multiple objectives in this article that it needs to allocation of disassembly tasks to the ordered group of disassembly Work Stations. Tasks-processing times are fuzzy numbers with triangular membership functions. Four objectives are acquired that include: (1) Minimization of number of disassembly work stations; (2) Minimization of sum of idle time periods from all work stations by ensuring from similar idle time at any work-station; (3) Maximization of preference in removal the hazardous parts at the shortest possible time; and (4) Maximization of preference in removal the high-demand parts before low-demand parts. This suggested model was initially solved by GAMS software and then using Genetic Algorithm (GA) in MATLAB software. This model has been utilized to balance automotive engine disassembly line in fuzzy environment. The fuzzy results derived from two software programs have been compared by ranking technique using mean and fuzzy dispersion with each other. The result of this comparison shows that genetic algorithm and solving it by MATLAB may be assumed as an efficient solution and effective algorithm to solve FDLBP in terms of quality of solution and determination of optimal sequence.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.469-476
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• 2020

Research reactors in-core experimental facilities are designed to provide the highest steady state flux for user's irradiation requirements. However, fuel conversion from highly enriched uranium (HEU) to low enriched uranium (LEU) driven by the ongoing effort to diminish proliferation risk, will impact reactor physics parameters. Preserving the reactor capability to produce the needed flux to perform its intended research functions, determines the conversion feasibility. This study investigates the neutron flux in the central experimental facility of two material test reactors (MTR), the IAEA generic10 MW benchmark reactor and the 22 MW s Egyptian Test and Research Reactor (ETRR-2). A 3D full core model with three uranium enrichment of 93%, 45%, and 20% was constructed utilizing the OpenMC particle transport Monte Carlo code. Neutronics calculations were performed for fresh fuel, the beginning of life cycle (BOL) and end of life cycle (EOL) for each of the three enrichments for both the IAEA 10 MW generic reactor and core 1/98 of the ETRR-2 reactor. Criticality calculations of the effective multiplication factor (K_eff) were executed for each of the twelve cases; results show a reasonable agreement with published benchmark values for both reactors. The thermal, epithermal and fast neutron fluxes were tallied across the core, utilizing the mesh tally capability of the code and are presented here. The axial flux in the central experimental facility was tallied at 1 cm intervals, for each of the cases; results for IAEA 10 MW show a maximum reduction of 14.32% in the thermal flux of LEU to that of the HEU, at EOL. The reduction of the thermal flux for fresh fuel was between 5.81% and 9.62%, with an average drop of 8.1%. At the BOL the thermal flux showed a larger reduction range of 6.92%-13.58% with an average drop of 10.73%. Furthermore, the fission reaction rate was calculated, results showed an increase in the peak fission rate of the LEU case compared to the HEU case. Results for the ETRR-2 reactor show an average increase of 62.31% in the thermal flux of LEU to that of the HEU due to the effect of spectrum hardening. The fission rate density increased with enrichment, resulting in 34% maximum increase in the HEU case compared to the LEU case at the assemblies surrounding the flux trap.

• Journal of Hospice and Palliative Care
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• v.14 no.2
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• pp.101-109
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• 2011

Purpose: The Assessing Care Of Vulnerable Elders project has developed indicators for the quality of the end-of-life (EOL) care. However, family members of cancer patients may have a different view on the quality indicators (QIs) established by health care experts. We evaluated the QIs from the family members' perspective. Methods: The information used in this study was gathered by surveying family members of cancer patients who were admitted to the inpatient hospice ward in Korea. A cross-sectional anonymous questionnaire was distributed to 120 potential respondents from July to October 2009. We included 69 responses in this study (effective response rate, 57.5%). Statistical analysis was performed by using SPSS for Win ver. 14.0, with independent t-test and Pearson's chi-square test. Results: Among QIs for good hospice care, families agreed the most on "Medical examination by the palliative care team or specialist" (88.4%) and "Dying in the family's presence" (88.4%). They agreed the least on "Discussing cardiopulmonary resuscitation with patients" (15.9%). Among QIs for bad hospice care, "Occurrence of fall or pressure ulcer are undesirable" showed the highest agreement rate (94.2%). The lowest agreement rate was 11.6% on "Dying in the hospital is undesirable." In addition, women, patients who were aware of their prognoses, and people with a high socioeconomic status tended to agree more on the QIs. Conclusion: Patients' families did not agree on some of the QIs recommended by previous studies. Family members' characteristics were related to their opinions on QIs.

• Journal of Hospice and Palliative Care
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• v.22 no.2
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• pp.87-99
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• 2019

Purpose: This study aimed to identify the difficulties with end-of-life care (EOLC) experienced by intensive care unit (ICU) nurses and to investigate their educational needs for EOLC. Methods: Mixed methods were used to survey ICU nurses at a university hospital. Quantitative data (N=106) were collected through a questionnaire and analyzed using an independent samples t-test, ANOVA, Mann-Whitney U test and $Scheff{\acute{e}}$ test. Qualitative data (N=19) were collected through focus group interviews and analyzed through qualitative content analysis. Results: The mean score on the difficulty of EOLC was 3.41 out of 5. The education needs derived from the qualitative analysis was categorized into four themes: 1) guidelines on professional EOLC, 2) spiritual care, 3) a program to take care of feelings of patients, families and nurses, and 4) activities to think about death. Conclusion: This study confirmed that ICU nurses were experiencing an extreme difficulty in providing EOLC. In addition, a qualitative analysis confirmed that they needed an EOL nursing program. To mitigate the difficulties experienced by nurses involved in EOLC, there is an urgent need to develop an education program for EOLC tailored to nurses' needs.

• Nuclear Engineering and Technology
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• v.14 no.4
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• pp.186-195
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• 1982

The steam line break accident for Kori Unit 1 is analyzed by a code SYSRAN which calculates nuclear power and heat flux using the point kinetics equation and the lumped-parameter model and calculates system transient using the mass and energy balance equation with the assumption of uniform reactor coolant system pressure. The 1.4 f $t^2$ steam line break accident is analyzed at EOL (End of Life), hot shutdown condition in which case the accident would be most severe. The steam discharge rate is assumed to follow the Moody critical flow model. The results reveal the peak heat flux of 38% of nominal full power value at 60 second after the accident initiates, which is higher than the FSAR result of 26%. Trends for the transient are in good agreement with FSAR results. A sensitivity study shows that this accident is most sensitive to the moderator density coefficient and the lower plenum mixing factor. The DNBR calculation under the assumption of $F_{{\Delta}H}$=3.66, which is used in the FSAR with all the control and the shutdown assemblies inserted except one B bank assembly and of Fz=1.55 shows that minimum DNBR reaches 1.62 at 60 second, indicating that the fuel failure is not anticipated to occur. The point kinetics equation, the lumped-parameter model and the system transient model which uses the mass and energy balance equation are verified to be effective to follow the system transient phenomena of the nuclear power plants.lear power plants.