http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Torkamany, Mohammad J. (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
-
Conceptual design of hybrid target for molybdenum-99 production based on heavywater
Torkamani Ali,Taghibi Khotbehsara Ali,Rahmani Faezeh,Khelvas Alexander,Bugaev Alexander,Ghasemi Farshad 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.5
Molybdenum-99 (99Mo) is used for preparing Technetium-99 m (99mTc), which is the most widely used isotope in nuclear medicine. In this work, a study for 99Mo production based on a high-power electron accelerator has been performed as an alternative approach to produce 99mTc. In this study, Monte Carlo MCNPX2.6 code has been used to examine a novel idea of simultaneous hybrid production of 99Mo via both photoneutron and neutron capture reactions using an electron accelerator in heavy water tank. It is expected that this conceptual design including an arrangement of metallic plates of 100Mo and 98Mo produces total activity of 97.5 Ci at the end of 20-h continuous e-beam irradiation (30 MeV, 10 mA)
-
Hadi Torkamani,Shahram Raygan,Carlos Garcia Mateo,Jafar Rassizadehghani,Yahya Palizdar,David San-Martin 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.4
In this research Rare Earth elements (RE), La and Ce (200 ppm), were added to a low carbon cast microalloyed steel todisclose their infl uence on the microstructure and impact toughness. It is suggested that RE are able to change the interactionbetween the inclusions and matrix during the Solidification process (comprising peritectic transformation), which couldaff ect the microstructural features and consequently the impact property; compared to the base steel a clear evolution wasobserved in nature and morphology of the inclusions present in the RE-added steel i.e. (1) they changed from MnS-based to(RE,Al)(S,O) and RE(S)-based; (2) they obtained an aspect ratio closer to 1 with a lower area fraction as well as a smalleraverage size. Besides, the microstructural examination of the matrix phases showed that a bimodal type of ferrite grain sizedistribution exists in both base and RE-added steels, while the mean ferrite grain size was reduced from 12 to 7 μm andthe bimodality was redressed in the RE-added steel. It was found that pearlite nodule size decreases from 9 to 6 μm in theRE-added steel; however, microalloying with RE caused only a slight decrease in pearlite volume fraction. After detailedfractography analyses, it was found that, compared to the based steel, the signifi cant enhancement of the impact toughnessin RE-added steel (from 63 to 100 J) can be mainly attributed to the Differences observed in the nature of the inclusions, theferrite grain size distribution, and the pearlite nodule size. The presence of carbides (cementite) at ferrite grain boundariesand probable change in distribution of Nb-nanoprecipitation (promoted by RE addition) can be considered as other reasonsaff ecting the impact toughness of steels under investigation.
-
Shahrokh Maalek,Hamid Heidary-Torkamani,Moharram Dolatshahi Pirooz,Seyed Taghi Omid Naeeini 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.3
In this research, the behavior of tube-in-tube BRBs (TiTBRBs) has been investigated. In a typical TiTBRB, the yielding core tube is located inside the outer restraining one to dissipate energy through extensive plastic deformation, while the outer restraining tube remains essentially elastic. With the aid of FE analyses, the monotonic and cyclic behavior of the proposed TiTBRBs have been studied as individual brace elements. Subsequently, a detailed finite element model of a representative single span-single story frame equipped with such a TiTBRB has been constructed and both monotonic and cyclic behavior of the proposed TiTBRBs have been explored under the application of the AISC loading protocol at the braced frame level. With the aid of backbone curves derived from the FE analyses, a simplified frame model has been developed and verified through comparison with the results of the detailed FE model. It has been shown that, the simplified model is capable of predicting closely the cyclic behavior of the TiTBRB frame and hence can be used for design purposes. Considering type of connection detail used in a frame, the TiTBRB member which behave satisfactorily at the brace element level under cyclic loading conditions, may suffer global buckling due to the flexural demand exerted from the frame to the brace member at its ends. The proposed TiTBRB suit tubular members of offshore structures and the application of such TiTBRB in a typical offshore platform has been introduced and studied in a single frame level using detailed FE model.
-
Effect of Ce Addition on the Tribological Behavior of ZK60 Mg-Alloy
S. M. Banijamali,Y. Palizdar,S. Najafi,A. Sheikhani,M. Soltan Ali Nezhad,P. Valizadeh Moghaddam,H. Torkamani 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8
The present work aims to study the tribological behavior of an extruded ZK60 alloy in the presence of Ce; in a previous study, among ZK60 alloys with diferent Ce addition rates, an alloy with 3 wt% of Ce was found to exhibit the mostpromising mechanical (e.g., hardness and strengths) properties, while its wear behavior remained unknown. The results ofmicrostructural examinations by optical and electron microscopes show that Ce addition reduces the grain size from 6.1 to2.0 μm. Besides, in addition to the precipitates already distributed in the base alloy (Mg7Zn3), Ce could promote the formation of a new precipitate (MgZn2Ce), increasing the total fraction of the precipitates. These microstructural evolutionsenhance the strengths of the studied ZK60 alloy, as the yield and tensile strengths increase from 212 to 308 MPa and from297 to 354 MPa, respectively. A pin on disc tribometer was employed to study the wear behavior of the developed alloyunder diferent normal loads (5, 20, 40, and 60 N). The results show that the base and Ce-added alloys exhibit almost asimilar frictional behavior, while the wear resistance of the Ce-added alloy is higher within the load ranges applied: (i) inlow load conditions (5 and 20 N), where the abrasive wear is the active mechanism, the precipitates in the Ce-added alloycould enhance the wear resistance. (ii) Under the load of 40 N, oxidative wear is also an operative wear mechanism, leadingto a sharp increase in the wear rate of the alloys. In this condition, Ce could provide a protective oxide layer, which couldimprove the wear resistance of the alloy. (iii) At a load of 60 N, both studied alloys exhibit a similar wear rate due to a severeoxidation condition. Therefore, beyond this loading condition, the microstructural evolutions (e.g., change in precipitationbehavior) caused by Ce addition can no longer contribute to the enhancement of wear resistance.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
