• Clean Technology
• /
• v.29 no.4
• /
• pp.288-296
• /
• 2023

Coal is abundantly available compared to other energy sources and is used as a versatile energy resource worldwide. To address the environmental issues stemming from conventional coal utilization, efforts are underway to develop clean coal utilization technologies, with IGCC technology being a notable example. In IGCC plants, coal is subjected to a CMD process where both drying and pulverization are achieved by supplying hot air. However, if the temperature of the supplied hot air is excessively high, it can lead to devolatilization and spontaneous combustion, thereby compromising the stable operation of the CMD process. This study aimed to measure the devolatilization and spontaneous combustion temperatures of different types of bituminous coal, and to explore their correlations with the characteristics of the coals. Six coal types exhibited devolatilization between 350 and 400 ℃, while three coal types showed devolatilization at temperatures exceeding 400 ℃. Spontaneous combustion ℃curred in one coal type below 100 ℃, six coal types between 100 and 150 ℃, and two coal types above 150 ℃. The measured initiation temperatures were compared with the coal characteristics including the oxygen, moisture, Fe₂O₃, and CaO content, the H/C ratio, and the O/C ratio to establish correlations. Regression analysis was used to calculate the regression coefficients and determination coefficients for each ignition temperature. It was found that 52.44% of the FC/VM data significantly influenced the volatile matter ignition temperature, and 59.10% of the Fe₂O₃ data significantly affected the spontaneous combustionignition temperature.

• Korean Journal of Construction Engineering and Management
• /
• v.25 no.2
• /
• pp.23-35
• /
• 2024

This study analyzed the correlation between each of the 12 influencing factors in FAR 16.04 and the decision-making process for construction contract types, using data from a total of 2,406 DoD Construction Acquisitions spanning from 2008 to 2022. The study considered 12 independent variables, grouped into 4 Characteristics with 3 factors each. Meanwhile, all other contract types were categorized into two types: Firm-Fixed-Price (FFP) and Cost-Reimbursement Contract (CRC), which served as the dependent variables. The findings revealed that FFP contracts significantly dominated in terms of acquisition volume. In line with prevailing beliefs, logistic data analysis and Analytical Hierarchy Process (AHP) analysis of Relative Weights from Experts' Survey demonstrated that independent variables like Uncertainty of the Scope of Work and Complexity found out to be increasing the likelihood of selecting CRC. The number of contractors in the market does indeed influence the possibilities of contract decision-making between CRC and FFP. Meanwhile, the p-values of the top 3 influencing factors on CRC from the AHP analysis-namely, Appropriateness of CAS, Project Urgency, and Cost Analysis-exceeded 0.05 in the binominal regression results, rendering it inconclusive whether they significantly influenced the construction contract type decision, particularly with respect to payment methods. This outcome partly results from the fact that a majority of respondents possessed specific experiences related to the USFK relocation project. Furthermore, influencing factors in construction projects behave differently than common beliefs suggest. As a result, it is imperative to consider the 12 influencing factors categorized into 4 Characteristics areas before establishing acquisition strategies for targeted construction projects.

• Tuberculosis and Respiratory Diseases
• /
• v.53 no.5
• /
• pp.519-529
• /
• 2002

Background : The therapeutic effects of surfactants on acute lung injury derive not only from their recruiting action on collapsed alveoli but also from their anti-inflammatory action in the alveolar sapce. This study evaluated the anti-inflammatory action of a surfactant in an acute lung injury model of rats by neutrophils were recollected from the BAL fluid and the NF-${\kappa}B$ activity of the neutrophilic nuclear protein was evaluated. Methods : Male Sprague-Dawley rats weighing approximately 300 gram were divided into 3 groups, which consisted of 6 rats respectively. In the control group, normal saline(3ml/kg) was instilled into the trachea twice with 30 minute interval. In two other groups, acute lung injury was induced by the intra-tracheal instillation of LPS(5mg/kg). Thirty minutes later, either a surfactant(ST group; 30mg/kg) or normal saline(NT group: 3ml/kg) was instilled via the trachea. Twenty-four hours after the LPS instillation, the BAL fluid was retrieved to measure the WBC count and cytokine(IL-$1{\beta}$ and IL-6) levels. The neutrophils were isolated from the BAL fluid and the nuclear protein was extracted to evaluate the NF-${\kappa}B$ activity using a eletrophoretic mobility shift assay(EMSA). Results : The WBC count of the BAL fluid of the ST group($3,221{\pm}1,914{\times}10^3/{\mu}l$) was higher than that of the control group($356{\pm}275{\times}10^3/{\mu}l$)(p<0.05) and lower than that of the NT group($5,561{\pm}1,757{\times}10^3/{\mu}l$)(p<0.05)). The BAL fluid level of IL-$1{\beta}$ from the NT group($2,064{\pm}1,082pg/ml$) was higher than those of the ST group($360{\pm}234pg/ml$)(p<0.05) and the control group(0pg/ml)p<0.05) and control group($49{\pm}62pg/ml$)(p<0.05). The NF-${\kappa}B$ activity of the neutrophilic nuclear protein in the ST group and NT group was similar. Conclusion : The surfactant, attenuates the alveolar inflammation in the acute lung injury of rats model. However, its anti-inflammatory action does no't appear to be mediated by the inhibition of NF-${\kappa}B$ activity.

• Radiation Oncology Journal
• /
• v.21 no.4
• /
• pp.261-268
• /
• 2003

Purpose: To report the results of curative treatment for patients with tonsil cancer by retrospective analysis. Materials and Methods: From Jan. 1995 till Dec. 2000, 27 patients with squamous cell carcinoma of the tonsil received curative treatment at Samsung Medical Center. Therapeutic decision was made through multidisciplinary conference, and curative radiation therapy was favored when, (1) the patient's condition was not fit for general anesthesia and surgery, (2) the patient refused surgery, (3) complete resection was presumed impossible, or (4) too severe disability was expected after surgery. Surgery was the main local modality in 17 patients (S$\pm$RT group), and radiation therapy in 10 (RT$\pm$CT group). The median follow-up period was 41 months. Results: AJCC stages were I/II in four, III in two, and IV in 21 patients. The 5-year disease-free survival rate was 73.3$\%$ in all patients, 70.6$\%$ in the S$\pm$RT group, and 77.8$\%$ in the RT$\pm$CT group. Treatment failure occurred in seven patients, all with stage III/IV, and all the failures occurred within 24 months of the start of treatment. Five patients among the S$\pm$CT group developed treatment failures; 2 local, 2 regional, and 1 distant (crude rate=29.4$\%$). Two patients among the RT$\pm$CT group developed failures; 1 synchronous local and regional, and 1 distant (crude rate=20.0$\%$). The 5-year overall survival rate was 77.0$\%$ in all patients, 80.9$\%$ in the S$\pm$RT group, and 70.0$\%$ in the RT$\pm$CT group. Conclusion: We could achieve favorable results that were comparable to previously reported data with respect to both the rates of local control and of survival by applying S$\pm$RT and RT$\pm$CT. RT$\pm$CT is judged to be an alternative option that can avoid the functional disability after surgical resection.

• Tuberculosis and Respiratory Diseases
• /
• v.66 no.3
• /
• pp.192-197
• /
• 2009

Background: Despite the benefits of home oxygen therapy in patients suffering chronic respiratory failure, previous reports in Korea revealed lower compliance to oxygen therapy and a shorter time for oxygen use than expected. However, these papers were published before oxygen therapy was covered by the national insurance system. Therefore, this study examined whether there were some changes in compliance, using time and other clinical features of home oxygen therapy after insurance coverage. Methods: This study reviewed the medical records of patients prescribed home oxygen therapy in our hospital from November 1, 2006 to September 31, 2008. The patients were interviewed either in person or by telephone to obtain information related to oxygen therapy. Results: During study period, a total 105 patients started home oxygen therapy. The mean age was 69 and 60 (57%) were male. The mean oxygen partial pressure in the arterial blood was 54.5 mmHg and oxygen saturation was 86.3%. Primary diseases that caused hypoxemia were COPD (n=64), lung cancer (n=14), Tb destroyed lung (n=12) and others. After oxygen therapy, more than 50% of patients experienced relief of their subjective dyspnea. The mean daily use of oxygen was 9.8${\pm}$7.3 hours and oxygen was not used during activity outside of their home (mean time, 5.4${\pm}$3.7 hours). Twenty four patients (36%) stopped using oxygen voluntarily 7${\pm}$4.7 months after being prescribed oxygen and showed a less severe pulmonary and right heart function. The causes of stopping were subjective symptom relief (n=11), inconvenience (n=6) and others (7). Conclusion: The prescription of home oxygen has increased since national insurance started to cover home oxygen therapy. However, the mean time for using oxygen is still shorter than expected. During activity of outside their home, patients could not use oxygen due to the absence of portable oxygen. Overall, continuous education to change the misunderstandings about oxygen therapy, more economic support from national insurance and coverage for portable oxygen are needed to extend the oxygen use time and maintain oxygen usage.

• Tuberculosis and Respiratory Diseases
• /
• v.54 no.4
• /
• pp.449-458
• /
• 2003

Background : Cyclosporin A(CsA) and tacrolimus(FK506) have been widely used as immunosuppressants. The effects of CsA, or FK506, on the $I{\kappa}B/NF-{\kappa}B$ pathway have been shown to vary according to the cell type. However, their effects on the $I{\kappa}B/NF-{\kappa}B$ pathway have not been reported in bronchial epithelial cells. In this study, the effects of CsA and FK506 on the $I{\kappa}B/NF-{\kappa}B$ pathway in bronchial epithelial cells, monocytes, lymphocytes and alveolar macrophages were evaluated. The relationship between their effects on the $I{\kappa}B/NF-{\kappa}B$ pathway and $I{\kappa}B$ kinase(IKK) activity was also investigated. Methods : BEAS-2B and A549 cells, pulmonary alveolar macrophages, peripheral blood monocytes and lymphocytes were used. The cells were pre-treated with CsA, or FK506, for various time periods, followed by stimulation with TNF-${\alpha}$, LPS or IL-$1{\beta}$. The $I{\kappa}B{\alpha}$ expressions were assayed by Western blot analyses. The IKK activity was evaluated by an in vitro immune complex kinase assay, using GST-$I{\kappa}B{\alpha}$ as the substrate. Results : Neither CsA nor FK506 affected the level of $I{\kappa}B{\alpha}$ expression in any of the cell types used in this study. CsA pre-treatment inhibited the TNF ${\alpha}$-induced $I{\kappa}B{\alpha}$ degradation in bronchial epithelial cells. In contrast, the TNF ${\alpha}$-induced $I{\kappa}B{\alpha}$ degradation was not affected by FK506 pre-treatment. However, FK506 suppressed the cytokine-induced $I{\kappa}B{\alpha}$ degradation in the pulmonary alveolar macrophages, peripheral blood monocytes and lymphocytes. The inhibitory effect of CsA, or FK506, on $I{\kappa}B{\alpha}$ degradation was not related to IKK. Conclusions : CsA and FK506 suppressed the $I{\kappa}B{\alpha}$ degradation in bronchial epithelial cells, monocytes, lymphocytes and alveolar macrophages, so this may not be mediated through IKK.

• Progress in Medical Physics
• /
• v.26 no.3
• /
• pp.168-177
• /
• 2015

For evaluating the treatment planning accurately, the quality assurance for treatment planning is recommended when patients were treated with IMRT which is complex and delicate. To realize this purpose, treatment plan quality assurance software can be used to verify the delivered dose accurately before and after of treatment. The purpose of this study is to evaluate the accuracy of treatment plan quality assurance software for each IMRT plan according to MLC DLG (dosimetric leaf gap). Novalis Tx with a built-in HD120 MLC was used in this study to acquire the MLC dynalog file be imported in MobiusFx. To establish IMRT plan, Eclipse RTP system was used and target and organ structures (multi-target, mock prostate, mock head/neck, C-shape case) were contoured in I'mRT phantom. To verify the difference of dose distribution according to DLG, MLC dynalog files were imported to MobiusFx software and changed the DLG (0.5, 0.7, 1.0, 1.3, 1.6 mm) values in MobiusFx. For evaluation dose, dose distribution was evaluated by using 3D gamma index for the gamma criteria 3% and distance to agreement 3 mm, and the point dose was acquired by using the CC13 ionization chamber in isocenter of I'mRT phantom. In the result for point dose, the mock head/neck and multi-target had difference about 4% and 3% in DLG 0.5 and 0.7 mm respectively, and the other DLGs had difference less than 3%. The gamma index passing-rate of mock head/neck were below 81% for PTV and cord, and multi-target were below 30% for center and superior target in DLGs 0.5, 0.7 mm, however, inferior target of multi-target case and parotid of mock head/neck case had 100.0% passing rate in all DLGs. The point dose of mock prostate showed difference below 3.0% in all DLGs, however, the passing rate of PTV were below 95% in 0.5, 0.7 mm DLGs, and the other DLGs were above 98%. The rectum and bladder had 100.0% passing rate in all DLGs. As the difference of point dose in C-shape were 3~9% except for 1.3 mm DLG, the passing rate of PTV in 1.0 1.3 mm were 96.7, 93.0% respectively. However, passing rate of the other DLGs were below 86% and core was 100.0% passing rate in all DLGs. In this study, we verified that the accuracy of treatment planning QA system can be affected by DLG values. For precise quality assurance for treatment technique using the MLC motion like IMRT and VMAT, we should use appropriate DLG value in linear accelerator and RTP system.

• Progress in Medical Physics
• /
• v.22 no.3
• /
• pp.140-147
• /
• 2011

The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

• Radiation Oncology Journal
• /
• v.27 no.4
• /
• pp.181-188
• /
• 2009

Purpose: The aim of this study was to evaluate the results of postoperative radiotherapy in a case of perihilar cholagiocarcinoma by analyzing overall survival rate, patterns of failure, prognostic factors for overall survival, and toxicity. Materials and Methods: Between January 1998 and March 2008, 38 patients with perihilar cholangiocarcinoma underwent a surgical resection and adjuvant radiotherapy. The median patient age was 59 years (range, 28 to 72 years), which included 23 men and 15 women. The extent of surgery was complete resection in 9 patients, microscopically positive margins in 25 patients, and a subtotal resection in 4 patients. The tumor bed and regional lymphatics initially received 45 Gy or 50 Gy, but was subsequently boosted to a total dose of 59.4 Gy or 60 Gy in incompletely resected patients. The median radiotherapy dose was 59.4 Gy. Concurrent chemotherapy was administered in 30 patients. The median follow-up period was 14 months (range, 6 to 45 months). Results: The 3-year overall survival and 3-year progression free survival rates were 30% and 8%, respectively. The median survival time was 28 months. A multivariate analysis showed that differentiation was the only significant factor for overall survival. The 3-year overall survival was 34% in R0 patients and 20% in R1 patients. No statistically significant differences in survival were found between the 2 groups (p=0.3067). The first site of failure was local in 18 patients (47%). No patient experienced grade 3 or higher acute toxicity and duodenal bleeding developed in 2 patients. Conclusion: Our results suggest that adjuvant RT might be a significant factor in patients with a positive margin following a radical resection. However, there was still a high locoregional recurrence rate following surgery and postoperative radiotherapy. Further study is necessary to enhance the effect of the adjuvant radiotherapy.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.1
• /
• pp.110-114
• /
• 2014

Purpose: The advancement in PET/CT test devices has decreased the test time and popularized the test, and PET/CT tests have continuously increased. However, this increases the exposure dose of radiation workers, too. This study aims to measure the radiation shielding rate of $^{18}F-FDG$ with a strong energy and the shielding effect when worker wore an apron during the PET/CT test. Also, this study compared the shielding rate with $^{99m}TC$ to minimize the exposure dose of radiation workers. Materials and Methods: This study targeted 10 patients who visited in this hospital for the PET/CT test for 8 days from May 2nd to 10th 2013, and the $^{18}F-FDG$ distribution room, patient relaxing room (stand by room after $^{18}F-FDG$ injection) and PET/CT test room were chosen as measuring spots. Then, the changes in the dose rate were measured before and after the application of the APRON. For an accurate measurement, the distance from patients or sources was fixed at 1M. Also, the same method applied to $^{99m}TC's$ Source in order to compare the reduction in the dose by the Apron. Results: 1) When there was only L-block in the $^{18}F-FDG$ distribution room, the average dose rate was $0.32{\mu}Sv$, and in the case of L-blockK+ apron, it was $0.23{\mu}Sv$. The differences in the dose and dose rate between the two cases were respectively, $0.09{\mu}Sv$ and 26%. 2) When there was no apron in the relaxing room, the average dose rate was $33.1{\mu}Sv$, and when there was an apron, it was $22.3{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $10.8{\mu}Sv$ and 33%. 3) When there was no APRON in the PET/CT room, the average dose rate was $6.9{\mu}Sv$, and there was an APRON, it was $5.5{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $1.4{\mu}Sv$ and 25%. 4) When there was no apron, the average dose rate of $^{99m}TC$ was $23.7{\mu}Sv$, and when there was an apron, it was $5.5{\mu}Sv$. The differences in the dose and dose rate between them were respectively, $18.2{\mu}Sv$ and 77%. Conclusion: According to the result of the experiment, $^{99m}TC$ injected into patients showed an average shielding rate of 77%, and $^{18F}FDG$ showed a relatively low shielding rate of 27%. When comparing the sources only, $^{18F}FDG$ showed a shielding rate of 17%, and $^{99m}TC$'s was 77%. Though it had a lower shielding effect than $^{99m}TC$, $^{18}F-FDG$ also had a shielding effect on the apron. Therefore, it is considered that wearing an apron appropriate for high energy like $^{18}F-FDG$ would minimize the exposure dose of radiation workers.