• Title/Summary/Keyword: Thermal meta

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Behaviour of Uranyl Phosphate Containing Solid Waste During Thermal Treatment for the Purpose of Sentencing and Immobilisation: Preliminary Results

  • Foster, Richard Ian;Sung, Hyun-Hee;Kim, Kwang-Wook;Lee, Keunyoung
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.3
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    • pp.407-414
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    • 2020
  • Thermal decomposition of the uranyl phosphate mineral phase meta-ankoleite (KUO2PO4·3H2O) has been considered in relation to high temperature thermal sintering for the immobilisation of a uranyl phosphate containing waste. Meta-ankoleite thermal decomposition was studied across the temperature range 25 - 1200℃ under an inert N2 atmosphere at 1 atm. It is shown that the meta-ankoleite mineral phase undergoes a double de-hydration event at 56.90 and 125.85℃. Subsequently, synthetically produced pure meta-ankoleite remains stable until at least 1150℃ exhibiting no apparent phase changes. In contrast, when present in a mixed waste the meta-ankoleite phase is not identifiable after thermal treatment indicating incorporation within the bulk waste either as an amorphous phase and/or as uranium oxide. Visual inspection of the waste post thermal treatment showed evidence of self-sintering owing to the presence of glass former materials, namely, silica (SiO2) and antimony(V) oxide (Sb2O5). Therefore, incorporation of the uranium phase into the waste as part of waste sentencing and immobilisation via high temperature sintering for the purpose of long-term disposal is deemed feasible.

A Study on the Improvement of the Thermal Stability of PE Separator for Lithium Secondary Battery Application Using Poly(meta-phenylene isophthalamide) (Poly(meta-phenylene isophthalamide)를 이용한 리튬이차전지용 PE 분리막의 고내열화 연구)

  • Park, Mina;Ra, Byung Ho;Bae, Jin-Young;Kim, Byung-Hyun;Choi, Won-Kun
    • Polymer(Korea)
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    • v.37 no.1
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    • pp.22-27
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    • 2013
  • In this study, we prepared separators with improved thermal stability by coating microporous polyethylene (PE) film for lithium secondary battery using poly(meta-phenylene isophthalamide) (Nomex). The mechanical and thermal properties of prepared separators were evaluated by thermal stability test and TMA as a function of the Nomex concentration and coating parameters. The corresponding coated PE separator showed better thermal and mechanical properties than the original PE separator. Electrochemical properties were also assessed by ionic conductivity, cyclic voltammetry and charge/discharge cycle.

Thermal Behavior of Dickite (딕카이트의 열적 특성 연구)

  • 조현구
    • Journal of the Mineralogical Society of Korea
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    • v.12 no.1
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    • pp.11-22
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    • 1999
  • Thermal behavior of dickite was studied by thermal analysis, X-ray diffraction analysis, electron microprobe analysis, and scanning electron microscopy, Dickite has an endothermic peak at about$ 650^{\circ}C$ and an exothermic one at $960^{\circ}C$ in the differential thermal analysis. The endothermic reaction is assigned to the decomposition of dickite to meta-dickite. Hydroxyl radicals are removed from dickite structure by the reaction, resulting in the weight loss about 10.5~14.5% and appearance of a 14$\AA$ phase different from other kaolin minerals. The reaction slowly proceed in the range of $200^{\circ}C$. As the completion of decomposition, aciclular mullite forms at the expense of meta-dickite plates with random crystallographic relationship. Mullites have diverse silica versus alumina ratio. The exothermic reaction without weight loss seems to be due to the formation of spinel and amorphous silica. The spinel phase shows cryptocrystalline globular morphology accompanying a little amount of silica. From spinel phase shows cryptocrystalling globular morphology accompanying a little amount of silica. From this work, it is suggested that mullite is formed from meta-dickite much lower temperature than the reported one in the previous works.

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High Temperature Properties of Fire Protection Materials Using Fly Ash and Meta-Kaolin (Fly Ash 및 Meta-Kaolin을 활용한 내화성 마감재의 고온특성)

  • Song, Hun;Chu, Yong-Sik;Lee, Jong-Kyu;Do, Jeong-Yun
    • Journal of the Korean Ceramic Society
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    • v.47 no.3
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    • pp.223-231
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    • 2010
  • The serious issue of tall building is to ensure the fire-resistance of high strength concrete. The fire resistant finishing method is necessarily essential in order to satisfy the fire resistance time of 3 h required by the law. The fire resistant finishing method is installed by applying a fire resistant material as a method of shotcrete or a fire resistant board to high strength concrete surface. This method can reduce the temperature increase of the reinforcement embedded in high strength concrete at high temperature due to the installation thickness control. This study is interested in identifying the effectiveness of inorganic alumino-silicate compounds including the inorganic admixture such as fly ash and meta-kaolin as the fire resistant finishing materials through the analysis of fire resistance and components properties at high temperature. The study results show that the fire resistant finishing material composed of fly ash and meta-kaolin has the thermal stability of the slight decrease of compressive strength at high temperature. These thermal stability is caused by the ceramic binding capacity induced by alkali activation reaction by the reason of the thermal analysis result not showing the decomposition of calcium hydrate. Inorganic compounds composed of fly ash and meta-kaolin is evaluated to be very effective as the fire resistance material for finishing to protect the concrete substrate by the reason of those simplicity in both application and manufacture. The additional study about the adhesion in the interface with concrete substrate is necessary for the purpose of the practical application.

Studies on the Properties of High Performance and High Strength Cement Mortar Using Meta Kaolin and Silica Fume (Meta Kaolin 및 Silica Fume을 이용한 고성능 고강도 시멘트 모르타르 특성에 관한 연구)

  • 정민철
    • Journal of the Korean Ceramic Society
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    • v.33 no.5
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    • pp.519-523
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    • 1996
  • Calcium hydroxide produced by cement hydration decreases the durability and the compressive strength of cement mortars. Pozzolanic property of meta kaolin and silica fume allows to avoid this drawback. Calcium hydroxide consumption according to pozzolanic raction is evaluated by Fourier differential thermal analysis. Particulary the properties of high performance and high strength of cement mortar containing above 10% meta kaolin and silica fume were resulted in the pozzolanic activity.

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Meta-analysis on the Effects of Exercise Therapy and Physiotherapy on Pain in Korean Patients with Chronic Low Back Pain (만성요통환자를 대상으로 운동치료 및 물리치료가 통증에 미치는 효과에 대한 메타분석)

  • Kim, Sung-Kyu;Lim, Bee-Oh
    • Korean Journal of Applied Biomechanics
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    • v.30 no.1
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    • pp.63-72
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    • 2020
  • Objective: The purpose of this study was to investigate meta-analysis on the effects of exercise therapy and physiotherapy on pain in korean patients with chronic low back pain. Method: Meta-analysis was performed on the type and method of treatment. A total of 23 experimental studies were coding into 31 individual studies, into types, methods, visual analogue scale (VAS), each pre/post value of the effect size was calculated by meta-analysis. Results: Sling exercise, stretching, thermal therapy, kinesio-taping, lumbar stabilization exercise, electrotherapy is large effect size (ES ≥ .08). In addition, big effects occurred in order of treatment period is more than 9 weeks, three times a week. Conclusion: Our results indicated that persistent treatment of chronic back pain is the most effective method of self-sufficiency rather than temporary relief.

Comparison of Thermal Ablation and Surgery for Low-Risk Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

  • Hyun Jin Kim;Se Jin Cho;Jung Hwan Baek
    • Korean Journal of Radiology
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    • v.22 no.10
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    • pp.1730-1741
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    • 2021
  • Objective: Although thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), comparison of treatment outcomes between thermal ablation and surgery has not yet been systematically evaluated. This study aimed to compare the efficacy and safety of thermal ablation and surgery for the treatment of low-risk PTMCs. Materials and Methods: Ovid-MEDLINE and EMBASE databases were searched for studies reporting comparisons of treatment results between thermal ablation and surgery for patients with low-risk PTMC published up to April 6, 2020. The analysis evaluated the efficacy (local tumor recurrence, occurrence of new tumor, metastasis, and rescue surgery) and safety (complication rate) of thermal ablation and surgery. Results: This systematic review included four studies with a total of 339 PTMCs in 339 patients who underwent thermal ablation and 320 PTMCs in 314 patients who underwent surgery. There was no local tumor recurrence or distant metastasis in either group. There was no significant difference in the pooled proportion of lymph node metastasis (2.6% with thermal ablation vs. 3.3% with surgery, p = 0.65), occurrence of new tumors (1.4% with thermal ablation vs. 1.3% with surgery, p = 0.85), or rescue surgery (2.6% with thermal ablation vs. 1.6% with surgery, p = 0.62). However, the pooled complication rate was significantly higher in the surgery group than in the ablation group (3.3% with thermal ablation vs. 7.8% with surgery, p = 0.03). Conclusion: Both thermal ablation and surgery are effective and safe options for the management of low-risk PTMCs, with thermal ablation achieving a lower complication rate. Therefore, thermal ablation may be considered as an alternative treatment option for low-risk PTMC in patients who refuse surgery and active surveillance or are ineligible for surgery.

The Spectral and Thermal Properties of Styrylquinolium Salts for Disc-Recordable Dyes

  • Song, Dong-Hyun;Kim, Jae-Pil;Lee, Chul-Joo;Park, Ki-Hong
    • Journal of Photoscience
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    • v.8 no.3_4
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    • pp.113-117
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    • 2001
  • Several styrylquinolium salts were synthesized to investigate their absorption and thermal properties, which had five different p-aminobenzene units and three different counter ions (iodide, perchlorate, and hexafluorophosphorate anion), respectively. Hydroxy, methoxy, and methyl group in the meta position to the amino group led to bathochromic shift, while Ν-ethyl-Ν-chloroethylamino unit instead of Ν,Ν-diethylamino unit resulted in hypsochromic shift. A dye having a methoxy group in the meta position to the amino group had the highest molar extinction coefficient ($\xi$), while a dye carrying chloro group in Ν-alkyl chains had the lowest $\xi$. The type of counter ions had no effect on spectral properties like the maximum absorption wavelength and $\xi$. All styryl dyes had exothermic peaks at decomposition in DSC curves. Among these styryl dyes, S2 series with perchlorate anions showed the strongest exothermic decomposition. From TGA spectra, S3 series with hexafluorophosphorate anions had the best thermal stability and the sharpest threshold at thermal decomposition.

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Muscimol as a treatment for nerve injury-related neuropathic pain: a systematic review and meta-analysis of preclinical studies

  • Hamzah Adel Ramawad;Parsa Paridari;Sajjad Jabermoradi;Pantea Gharin;Amirmohammad Toloui;Saeed Safari;Mahmoud Yousefifard
    • The Korean Journal of Pain
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    • v.36 no.4
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    • pp.425-440
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    • 2023
  • Background: Muscimol's quick onset and GABAergic properties make it a promising candidate for the treatment of pain. This systematic review and meta-analysis of preclinical studies aimed at summarizing the evidence regarding the efficacy of muscimol administration in the amelioration of nerve injury-related neuropathic pain. Methods: Two independent researchers performed the screening process in Medline, Embase, Scopus and Web of Science extracting data were extracted into a checklist designed according to the PRISMA guideline. A standardized mean difference (SMD [95% confidence interval]) was calculated for each. To assess the heterogeneity between studies, 2 and chi-square tests were utilized. In the case of heterogeneity, meta-regression and subgroup analyses were performed to identify the potential source. Results: Twenty-two articles met the inclusion criteria. Pooled data analysis showed that the administration of muscimol during the peak effect causes a significant reduction in mechanical allodynia (SMD = 1.78 [1.45-2.11]; P < 0.0001; I2 = 72.70%), mechanical hyperalgesia (SMD = 1.62 [1.28-1.96]; P < 0.0001; I2 = 40.66%), and thermal hyperalgesia (SMD = 2.59 [1.79-3.39]; P < 0.0001; I2 = 80.33%). This significant amendment of pain was observed at a declining rate from 15 minutes to at least 180 minutes post-treatment in mechanical allodynia and mechanical hyperalgesia, and up to 30 minutes in thermal hyperalgesia (P < 0 .0001). Conclusions: Muscimol is effective in the amelioration of mechanical allodynia, mechanical hyperalgesia, and thermal hyperalgesia, exerting its analgesic effects 15 minutes after administration for up to at least 3 hours.

Preparation and Characteristics of Poly(m-phenyleneisophthalamide)/Poly Amic Acid Blended Film (m-Aramid/PAA 블렌딩 필름의 제조 및 특성)

  • Jisu Lee;Ayoung Jang;Ji Eun Gwon;Seung Woo Lee;Sang Oh Lee;Jaewoong Lee
    • Textile Coloration and Finishing
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    • v.35 no.4
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    • pp.221-230
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    • 2023
  • Meta-aramid and polyamic acid were separated and the manufactured films were analyzed for their integration and logarithmic properties. The miscibility of meta-aramid and polyamic acid was analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy. Using calorimetric analysis and differential scanning calorimetry, the storage of meta-aramid and polyamic acid, indicated on the right side of the column, was analyzed. It was confirmed that the initial thermal resistance occurs because the polyamic acid is accounted for in the meta-aramid, and the glass transition temperature and persistence phenomenon are explained.