The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
M. Strach - One of the best experts on this subject based on the ideXlab platform.
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the effect of manganese and silicon on the kinetics of phase transformations during tempering Continuous Heating transformation cht curves
Journal of Materials Processing Technology, 1997Co-Authors: J. Pacyna, A Jȩdrzejewskastrach, M. StrachAbstract:Abstract The effect of Mn and Si on the kinetics of Phase Transformations was determined at Continuous Heating from the quenched state. The investigations were executed on the model alloys of the weak “background” of other elements. The results were presented on the CHT curves (Continuous Heating Transformations) in the temperature-time-transformation system.
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The effect of manganese and silicon on the kinetics of phase transformations during tempering — Continuous Heating Transformation (CHT) curves
Journal of Materials Processing Technology, 1997Co-Authors: J. Pacyna, A. Jȩdrzejewska-strach, M. StrachAbstract:Abstract The effect of Mn and Si on the kinetics of Phase Transformations was determined at Continuous Heating from the quenched state. The investigations were executed on the model alloys of the weak “background” of other elements. The results were presented on the CHT curves (Continuous Heating Transformations) in the temperature-time-transformation system.
J. Pacyna - One of the best experts on this subject based on the ideXlab platform.
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Influence of the Carbon Content on the Kinetics of Phase Transformations During Continuous Heating from As-Quenched State in a Cr-Mn-Mo Model Alloys / Wpływ Zawartości Węgla Na Kinetykę Przemian Fazowych Podczas Nagrzewania Ze Stanu Zahartowanego W S
Archives of Metallurgy and Materials, 2012Co-Authors: R. Dziurka, J. PacynaAbstract:The presented work concerns the research on the kinetics of phase transformations during Continuous Heating from as-quenched state of three Cr-Mn-Mo model alloys with a different carbon content. The kinetics of phase transformations during Continuous Heating of investigated alloys was presented on the CHT (Continuous, Heating, Transformation) diagrams. The CHT diagrams were made on the grounds of dilatograms recorded for quenched samples, heated with various rates. Also the methodology of the dilatometric samples preparation and the method of the characteristic points determination was described. The investigated alloys are the model alloys. Taking into account their chemical compositions the possibility of improving their properties by means of the heat treatment can be expected. The investigations of the carbon influence on microstructures of model alloys with Cr-Mn-Mo were carried out. Broadening the knowledge on the carbon influence on the kinetics of phase transformations during Continuous Heating from as-quenched state, will help in designing new alloys with a better properties.
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the effect of manganese and silicon on the kinetics of phase transformations during tempering Continuous Heating transformation cht curves
Journal of Materials Processing Technology, 1997Co-Authors: J. Pacyna, A Jȩdrzejewskastrach, M. StrachAbstract:Abstract The effect of Mn and Si on the kinetics of Phase Transformations was determined at Continuous Heating from the quenched state. The investigations were executed on the model alloys of the weak “background” of other elements. The results were presented on the CHT curves (Continuous Heating Transformations) in the temperature-time-transformation system.
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The effect of manganese and silicon on the kinetics of phase transformations during tempering — Continuous Heating Transformation (CHT) curves
Journal of Materials Processing Technology, 1997Co-Authors: J. Pacyna, A. Jȩdrzejewska-strach, M. StrachAbstract:Abstract The effect of Mn and Si on the kinetics of Phase Transformations was determined at Continuous Heating from the quenched state. The investigations were executed on the model alloys of the weak “background” of other elements. The results were presented on the CHT curves (Continuous Heating Transformations) in the temperature-time-transformation system.
S V Ulshin - One of the best experts on this subject based on the ideXlab platform.
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grain growth and texture evolution in ti 6al 4v during beta annealing under Continuous Heating conditions
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2002Co-Authors: O M Ivasishin, S L Semiatin, P E Markovsky, S V Shevchenko, S V UlshinAbstract:Abstract The kinetics of beta grain growth during Continuous Heating for two texturally-different, but microstructurally-equivalent, lots of Ti–6Al–4V material were determined using a direct-resistance-Heating technique. Heating rates of 0.42, 5, 10, and 50 K s−1 were utilized. After reaching the peak temperature, a special cooling procedure was utilized to avoid complete decomposition of the beta phase during cool-down and thus enable direct determination of its texture at the end of high-temperature annealing. It was found that beta grain growth is strongly affected by texture whose evolution can give rise to a behavior which is disContinuous in nature. As a result, dramatic differences in grain-growth behavior were noted in the two lots of material and were explained in terms of variations in beta texture evolution during heat treatment.
Chigyu Lee - One of the best experts on this subject based on the ideXlab platform.
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A comparative study of ultra-trace-level uranium by thermal ionization mass spectrometry with Continuous Heating: Static and peak-jumping modes
Nuclear Engineering and Technology, 2020Co-Authors: Chigyu Lee, Ranhee Park, Jinkyu Park, Sang Ho LimAbstract:Abstract For ensuring nuclear safeguards, we report the analytical signal-detection performance of thermal ionization mass spectrometry (TIMS) with Continuous Heating for the measurement of isotopic ratios in samples containing ultra-trace amounts of uranium. As methods for detecting uranium signals, peak-jumping mode using a single detector and static mode using multiple detectors were examined with U100 (10% 235U-enriched) uranium standard samples in the femtogram-to-picogram range. Uranium isotope ratios, n(235U)/n(238U), were measured down to levels of 1 fg and 3 fg in static and peak-jumping modes, respectively, while n(234U)/n(238U) and n(236U)/n(238U) values were measured down to levels of 100 fg in both modes. In addition, the dependency of the 238U signal intensity on sample quantity exhibited similar tendencies in both modes. The precisions of the isotope ratios obtained in the static mode over all sample ranges used in this study were overall slightly higher than those obtained in peak-jumping mode. These results indicate that isotope ratio measurements by TIMS with Continuous Heating are almost independent of the detection method, i.e., peak-jumping mode or static mode, which is characteristic of isotope-ratio measurements using the TIMS method with Continuous Heating. TIMS with Continuous Heating is advantageous as it exhibits the properties of multiple detectors within a single detector, and is expected to be used in various fields in addition to ensuring nuclear safeguards.
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Ultra-trace analysis of plutonium by thermal ionization mass spectrometry with a Continuous Heating technique without chemical separation.
Talanta, 2015Co-Authors: Chigyu Lee, Daisuke Suzuki, Masaaki Magara, Fumitaka Esaka, Kyuseok SongAbstract:Abstract Thermal ionization mass spectrometry (TIMS) with a Continuous Heating technique is known as an effective method for measuring the isotope ratio in trace amounts of uranium. In this study, the analytical performance of thermal ionization mass spectrometry with a Continuous Heating technique was investigated using a standard plutonium solution (SRM 947). The influence of the Heating rate of the evaporation filament on the precision and accuracy of the isotope ratios was examined using a plutonium solution sample at the fg level. Changing the Heating rate of the evaporation filament on samples ranging from 0.1 fg to 1000 fg revealed that the influence of the Heating rate on the precision and accuracy of the isotope ratios was slight around the Heating rate range of 100–250 mA/min. All of the isotope ratios of plutonium (SRM 947), 238Pu/239Pu, 240Pu/239Pu, 241Pu/239Pu and 242Pu/239Pu, were measured down to sample amounts of 70 fg. The ratio of 240Pu/239Pu was measured down to a sample amount of 0.1 fg, which corresponds to a PuO2 particle with a diameter of 0.2 μm. Moreover, the signals of 239Pu could be detected with a sample amount of 0.03 fg, which corresponds to the detection limit of 239Pu of 0.006 fg as estimated by the 3-sigma criterion. 238Pu and 238U were clearly distinguished owing to the difference in the evaporation temperature between 238Pu and 238U. In addition, 241Pu and 241Am formed by the decay of 241Pu can be discriminated owing to the difference in the evaporation temperature. As a result, the ratios of 238Pu/239Pu and 241Pu/239Pu as well as 240Pu/239Pu and 242Pu/239Pu in plutonium samples could be measured by TIMS with a Continuous Heating technique and without any chemical separation processes.
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a new method for isotope ratio measurement of uranium in trace amount by thermal ionization mass spectrometry the Continuous Heating method
International Journal of Mass Spectrometry, 2010Co-Authors: Daisuke Suzuki, Yoko Saitokokubu, S Sakurai, Chigyu Lee, Masaaki Magara, Kazunari Iguchi, Takaumi KimuraAbstract:Abstract A new method for isotope ratio measurement with thermal ionization mass spectrometry (TIMS), “Continuous Heating method”, was developed in order to determine an accurate isotope ratio of uranium ranging from sub-picograms to several dozen picograms. In this method, signals were measured during evaporation of an entire sample in the same way as in the “total evaporation method”; however, part of the higher detected signals was used for calculation of the isotope ratio. The Continuous Heating method can measure the ratios with high reproducibility regardless of the sample amount and the skill of operators because procedures of measurement and data calculation were standardized, enabling accurate correction of the mass discrimination effect. By using the optimized procedures, the relative standard deviation (2 σ ) of 235 U/ 238 U ratio in CRM U350 particle (35% 235 U enrichment) with a diameter of about 1 μm was less than 2%. When 235 U/ 238 U ratios in IRMM 184 (natural uranium) solution samples of uranium of 0.4, 4 and 44 pg measured by the Continuous Heating method were compared with those measured by the conventional method and the total evaporation method, which were well-known methods of TIMS, there was no difference in the case of measurement of a larger amount of samples. However, the Continuous Heating method showed the most accurate result for the smallest amount of samples.
Kyuseok Song - One of the best experts on this subject based on the ideXlab platform.
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Ultra-trace analysis of plutonium by thermal ionization mass spectrometry with a Continuous Heating technique without chemical separation.
Talanta, 2015Co-Authors: Chigyu Lee, Daisuke Suzuki, Masaaki Magara, Fumitaka Esaka, Kyuseok SongAbstract:Abstract Thermal ionization mass spectrometry (TIMS) with a Continuous Heating technique is known as an effective method for measuring the isotope ratio in trace amounts of uranium. In this study, the analytical performance of thermal ionization mass spectrometry with a Continuous Heating technique was investigated using a standard plutonium solution (SRM 947). The influence of the Heating rate of the evaporation filament on the precision and accuracy of the isotope ratios was examined using a plutonium solution sample at the fg level. Changing the Heating rate of the evaporation filament on samples ranging from 0.1 fg to 1000 fg revealed that the influence of the Heating rate on the precision and accuracy of the isotope ratios was slight around the Heating rate range of 100–250 mA/min. All of the isotope ratios of plutonium (SRM 947), 238Pu/239Pu, 240Pu/239Pu, 241Pu/239Pu and 242Pu/239Pu, were measured down to sample amounts of 70 fg. The ratio of 240Pu/239Pu was measured down to a sample amount of 0.1 fg, which corresponds to a PuO2 particle with a diameter of 0.2 μm. Moreover, the signals of 239Pu could be detected with a sample amount of 0.03 fg, which corresponds to the detection limit of 239Pu of 0.006 fg as estimated by the 3-sigma criterion. 238Pu and 238U were clearly distinguished owing to the difference in the evaporation temperature between 238Pu and 238U. In addition, 241Pu and 241Am formed by the decay of 241Pu can be discriminated owing to the difference in the evaporation temperature. As a result, the ratios of 238Pu/239Pu and 241Pu/239Pu as well as 240Pu/239Pu and 242Pu/239Pu in plutonium samples could be measured by TIMS with a Continuous Heating technique and without any chemical separation processes.