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Risks of non-conservative design according to ASME B31.1 for high-temperature piping subjected to long-term operation in the creep range

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Nuclear Science and Techniques 2019年第5期30卷 59-69页

作者： Hyeong-Yeon Lee Seok-Kwon Son min-Gu Won Ji-Young jeong korea Atomic Energy Research Institute National Fusion Research Institute School of Mechanical Engineering Sungkyunkwan University

This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity analysis of the hold time. Design evaluations of hightemperature piping were conducted over a range of hold times in the creep regime according to ASME B31.1,which implicitly considers the creep effects, and the French high-temperature design code of the RCC-MRx, which explicitly considers the creep effects. Conservatisms were quantified among the codes in terms of the hold times. In the case of B31.1, the design evaluation results do not change depending on the hold time at high temperature,whereas in the case of RCC-MRx, they do. It was shown that the design limits of RCC-MRx were exceeded when the hold time exceeded certain values, whereas those of B31.1 were satisfied regardless of the hold times. Thus, the design evaluations according to B31.1 did not consistently yield conservative results and might lead to non-conservative results in the case of long-term operations in the creep range.

关键词： ASME B31.1 Creep Hold time Hightemperature piping RCC-MRx Sensitivity analysis

Comparison of wrist motion classification methods using surface electromyogram

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Journal of Central South University 2013年第4期20卷 960-968页

作者： jeong Eui-chul KIM Seo-jun SONG Young-rok LEE Sang-min Department of Electronic Engineering Inha University

The Gaussian mixture model (GMM), k-nearest neighbor (k-NN), quadratic discriminant analysis (QDA), and linear discriminant analysis (LDA) were compared to classify wrist motions using surface electromyogram (EMG). Effect of feature selection in EMG signal processing was also verified by comparing classification accuracy of each feature, and the enhancement of classification accuracy by normalization was confirmed. EMG signals were acquired from two electrodes placed on the forearm of twenty eight healthy subjects and used for recognition of wrist motion. Features were extracted from the obtained EMG signals in the time domain and were applied to classification methods. The difference absolute mean value (DAMV), difference absolute standard deviation value (DASDV), mean absolute value (MAV), root mean square (RMS) were used for composing 16 double features which were combined of two channels. In the classification methods, the highest accuracy of classification showed in the GMM. The most effective combination of classification method and double feature was (MAV, DAMV) of GMM and its classification accuracy was 96.85%. The results of normalization were better than those of non-normalization in GMM, k-NN, and LDA.

关键词： Gaussian mixture model k-nearest neighbor quadratic discriminant analysis linear discriminant analysis electromyogram (EMG) pattern classification feature extraction

Spatial distribution and comparative evaluation of phosphorus release rate in benthic sediments of an estuary dam

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International Journal of Sediment Research 2022年第3期37卷 355-369页

作者： Yongsik Song Yong-Hoon jeong Chang-min Shin Dong-Heui Kwak Geosystem Research Corporation Department of Civil Engineering Jeonbuk National University Department of Bio-Convergence Science Jeonbuk National University Water Quality Assessment Research Division National Institute of Environmental Research Department of Bioactive Materials Science Jeonbuk National University

A series of experiments and simulations were performed to ascertain the rate at which phosphorus is released using a water quality model in Saemangeum Lake, an artificially constructed lake located in an estuary. The general inflow of seawater once a day contributed to the formation of a halocline in the lake water, which caused variation in the vertical concentration of dissolved oxygen. The halocline was mainly observed in the deep downstream regions of Saemangeum Lake that are close to the open sea. In contrast, the shallower regions upstream, which are under the influence of pollutant-loading from upstream rivers, exhibited high concentrations of chemical oxygen demand, total phosphorus, and Chl-a,resulting in lower water quality than the downstream regions. Laboratory experiments investigating the release of phosphorus at five representative locations showed that the upstream release flux, where the halocline was weaker, was higher than that downstream, where the initial level of phosphorus sedimentation was high. In particular, a need for an accurate evaluation method for the release of phosphorus at each site was suggested as slight differences were obtained depending on the estimation method used at each representative location. The results of the phosphorus release experiments led to the use of time-weighted integration(TWI), terminated time evaluation, and statistical mean value; the Environmental Fluid Dynamics Code-National Institute of Environment Research model, a widely used water quality model for studying retention watersheds, was applied to the simulation of hydraulic and water quality characteristics for the Saemangeum Lake and its surrounding waters. The result of the water quality simulation indicated the highest reproducibility for release-time TWI so that TWI values were more useful in predicting phosphorus concentrations and the subsequent management of water quality.

关键词： Eutrophication Phosphorus release Salinity Sediments Water quality simulation Environmental Fluid Dynamics Code–National Institute of Environment Research model (EFDC-NIER)

Diagnostic Indicators for Blood Stasis Syndrome Patients with Gynaecological Diseases

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Chinese Journal of Integrative Medicine 2018年第10期24卷 752-757页

作者： Jeeyoun Jung Mi Mi ko Myeong Soo Lee So min Lee Ju Ah Lee korea Medicine Fundamental Research Division Korea Institute of Oriental Medicine Clinical Research Division Korea Institute of Oriental Medicine

Objective： To investigate the important diagnostic indicators for blood stasis syndrome （BSS） in patients of childbearing age with gynaecological diseases. Methods： A partial least squared-discriminant analysis （PLS-DA） were applied to BSS symptoms data of patients with gynaecological diseases, and the diagnostic indicators used by doctors of korean medicine （DKMs） among BSS patients with gynaecological diseases were also investigated. Results： A total of 103 patients of childbearing age with gynaecological diseases and 40 healthy controls were enrolled. Among the 103 patients, 63 （61.7%） and 40 （38.8%） were diagnosed with BSS and non-BSS, respectively, and BSS patients exhibited a more severe extent of disease. A score plot of PLS-DA showed clearly different patterns among the 3 groups. Based on the variable importance on projection of PLS-DA model, menstrual pains, dark lumps in the menstrual blood, ileocoecal tenderness and resistance, sharp pains, and sublingual varicosities were selected as the top five most important indicators. Moreover, more than 75% of DKMs chose dark lumps in menstrual blood, menstrual pain, and dark menstrual blood as the diagnostic indicators of BSS in patients with gynaecological diseases, and more than 49% of them also considered sharp pains, dark red tongue, sublingual varicosities, and tendency to bruise easily as diagnostic indicators of BSS. Conclusion： DKMs focused on menstrual symptoms and certain gynaecological symptoms to diagnose BSS patients of childbearing age with female diseases.

关键词： blood stasis syndrome diagnosis gynaecological disease pattern identification

Investigation of prodromal features in metabolic syndrome based on transcriptome analysis

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Genes & Diseases 2023年第3期10卷 708-711页

作者： Sang-min Park Musun Park Hyo-jeong Ban Su-Jin Baek Soo Yeon Kim Siwoo Lee Hee-jeong Jin korean Medicine(KM)Data Division Korea Institute of Oriental MedicineDaejeon 34054Republic of Korea College of Pharmacy Chungnam National UniversityDaejeon 34134Republic of Korea

Metabolic syndrome(MetS)is a complex condition that significantly increases the risk of several diseases,including heart disease and *** with MetS show both pro-inflammatory and pro-thrombotic states;however,the state... 详细信息

关键词： diseases Metabolic Patients

A feasible route to produce 1.1 GPa ferritic-based low-Mn lightweight steels with ductility of 47%

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Journal of Materials Science & Technology 2022年第22期117卷 225-237页

作者： Kwang Kyu ko Hyo Ju Bae Eun Hye Park Hyeon-Uk jeong Hyoung Seok Park Jae Seok jeong Jung Gi Kim Hyokyung Sung Nokeun Park Jae Bok Seol Department of Materials Engineering and Convergence Technology Center for K-metalGyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering Yeungnam UniversityGyeongbuk 38541South Korea Materials Research Team R&D Hyundai MobisYongin 16891South Korea Materials Technology Development Team Doosan Heavy Industries&ConstructionChangwon 51711South Korea

High- and medium-Mn (H/M-Mn) base lightweight steels are a class of ultrastrong structural materials with high ductility compared to their low-Mn counterparts with low strength and poor ***, producing these H/M-Mn materials requires the advanced or high-tech manufacturing techniques, which can unavoidably provoke labor and cost concerns. Herein, we have developed a facilestrategy that circumvents the strength–ductility trade-off in low-Mn ferritic lightweight steels, by employing low-temperature tempering-induced partitioning (LTP). This LTP treatment affords a typical Fe-2.8Mn-5.7Al-0.3C (wt.%) steel with a heterogeneous size-distribution of metastable austenite embeddedin a ferrite matrix for partitioning more carbon into smaller austenite grains than into the larger austenite ones. This size-dependent partitioning results in slip plane spacing modification and lattice strain,which act through dislocation engineering. We ascribe the simultaneous improvement in strength andtotal elongation to both the size-dependent dislocation movement in austenite grains and the controlleddeformation-induced martensitic transformation. The low-carbon-partitioned large austenite grains increase the strength and ductility as a consequence of the combined martensitic transformation andhigh dislocation density-induced hardening and by interface strengthening. Additionally, high-carbonpartitioned small austenite grains enhance the strength and ductility by planar dislocation glide (inthe low strain regime) and by cross-slipping and delayed martensitic transformation (in the high strainregime). The concept of size-dependent dislocation engineering may provide different pathways for developing a wide range of heterogeneous-structured low-Mn lightweight steels, suggesting that LTP maybe desirable for broad industrial applications at an economic cost.

关键词： Low-Mn lightweight steel Carbon partitioning Metastable austenite Dislocation movement

Novel extended C-m models of flow stress for accurate mechanical and metallurgical calculations and comparison with traditional flow models

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Journal of Magnesium and Alloys 2022年第9期10卷 2516-2533页

作者： Man Soo Joun Mohd Kaswandee Razali Jae Dong Yoo min Cheol Kim jeong Muk Choi ReCAFT Gyeongsang National UniversityGraduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea Gyeongsang National University Graduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea MFRC Research CenterJinju 52818South Korea Jinhap Daejeon 34302South Korea

Here,we developed novel extended piecewise bilinear power law(C-m)models to describe flow stresses under broad ranges of strain,strain rate,and temperature for mechanical and metallurgical calculations during metal forming at elevated *** traditional C-m model is improved upon by formulating the material parameters C and m,defined at sample strains and temperatures as functions of the strain *** coefficients are described as a linear combination of the basis functions defined in piecewise patches of the sample strain and temperature domain.A comparison with traditional closed-form function flow models revealed that our approach using the extended piecewise bilinear C-m model is superior in terms of accuracy,ease of use,and adaptability;additionally,the extended C-m model was applicable to numerical analysis of mechanical,metallurgical,and microstructural ***,metallurgy-related values can be calculated directly from the flow stress *** the proposed model was developed for materials at elevated temperatures,it can be applied over a broad temperature range.

关键词： Flow stress Power law model Piecewise bilinear function Numerical analysis Microstructural prediction Peak strain

Micro Manipulation Using Magnetic Microrobots

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Journal of Bionic Engineering 2016年第4期13卷 515-524页

作者： Hoyeon Kim Jamel Ali U Kei Cheang Jinwoo jeong din Seok Kim min dun Kim Department of Mechanical Engineering Southern Methodist University Dallas TX75272 USA Department of MechanicaI Engineering and Mechanics Drexel University Philadelphia PA 19104 USA Center for Bionics Korea Institute of Science and Technology 5 Hwarang-ro 14-gil Seongbuk-gu Seou102792 Republic of Korea

When developing microscale robotic systems it is desired that they are capable of performing microscale tasks such as small scale manipulation and transport. In this paper, we demonstrate the transport of microscale objects using single or multiple microrobots in low Reynolds number fluidic environment. The microrobot is composed of a ‘U＇ shaped SU-8 body, coated on one side with nickel. Once the nickel coating is magnetized, the motion of the microrobots can be driven by external magnetic fields. To invoke different responses from two microrobots under a global magnetic field, two batches of microrobots were fabricated with different thicknesses of nickel coating as a way to promote heterogeneity within the microrobot population. The heterogeneity in magnetic content induces different spatial and temporal responses under the same control input, resulting in differences in movement speed. The nickel coated microstructure is manually controlled through a user interface developed using C＋＋. This paper presents a control strategy to navigate the microrobots by controlling the direction and strength of ex- ternally applied magnetic field, as well as orientation of the microrobots based on their polarity. In addition, multiple micro- robots are used to perform transport tasks.

关键词： microrobot magnetic control microtransport magnetic polarity micromanipulation

Effects of granulation process variables on the physical properties of dosage forms by combination of experimental design and principal component analysis

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Asian Journal of Pharmaceutical Sciences 2019年第3期14卷 287-304页

作者： Prakash Thapa Du Hyung Choi min Soo Kim Seong Hoon jeong College of Pharmacy Dongguk UniversityGyeonggi10326Republic of Korea Department of Pharmaceutical Engineering Inje UniversityGyeongnam50834Republic of Korea College of Pharmacy Pusan National UniversityBusan46241Republic of Korea

The current study was to understand how process variables of high shear wet granulations affect physical properties of granules and tablets. The knowledge gained was intended to be used for Quality-by-Design based process design and optimization. The variables were selected based on the risk assessment as impeller speed, liquid addition rate, and wet massing time. Formulation compositions were kept constant to minimize their influence on granules properties. Multiple linear regression models were built providing understanding of the impact of each variable on granule hardness, Carr’s index, tablet tensile strength, surface mean diameter of granules, and compression behavior. The experimental results showed that the impact of impeller speed was more dominant compared to wet massing time and water addition rate. The results also revealed that quality of granules and tablets could be optimized by adjusting specific process variables(impeller speed 1193 rpm, water spray rate 3.7 ml/min, and wet massing time 2.84 min). Overall desirability was 0.84 suggesting that the response values were closer to the target one. The SEM image of granules showed that spherical and smooth granules produced at higher impeller speed, whereas rough and irregular shape granules at lower speed. Moreover, multivariate data analysis demonstrated that impeller speed and massing time had strong correlation with the granule and tablet properties. In overall, the combined experimental design and principal component analysis approach allowed to better understand the correlation between process variables and granules and tablet attributes.

关键词： Experimental design Principal component analysis High shear granulation Process parameter