Westgard Multi-Rules의 효율적 적용과 조치사항의 개선

정흥수,오윤정,배진수,백진영,황보라,신용환,Jung, Heung Soo,Oh, Youn Jung,Bae, Jin Soo,Baek, Jin Young,Hwang, Bo ra,Shin, Yong Hwan 대한핵의학기술학회 2017 핵의학 기술 Vol.21 No.1

검사의 질 향상과 국제표준화의 상용화 정도관리물질을 이용한 Westgard multi-rules 적용의 유용성은 이미 알려져 있다. 그러나 핵의학 체외검사의 특성상 정도관리물질과 환자검체의 동시 계측으로 인한 측정횟수의 증가에 따라 Westgard multi-rules법을 적용함에 있어 어려움이 있다. 이에 본 연구는 핵의학 체외검사에서 상용화 정도관리물질을 이용한 Westgard multi-rules 적용의 유용성과 보완, 개선을 통해 내부정도관리의 효율성 향상을 조사하였다. 2013년 01월부터 2016년 06월까지 삼성서울병원 핵의학과 체외검사실 통합의료시스템에 기록된 총 282건의 적용된 계통오차 multi-rules (22s, 101s)과 117건의 조치사항 기록을 분석하였다. 조치사항은 multi-rules 중 계통오차의 규칙이 적용 되었을 때 기록하는 원인분석으로 정도관리물질 오류, 실험과정 오류, 검사키트 로트번호 관리 오류, 기타 등 총 4개의 대분류로 구성하였다. Westgard multi-rules 적용을 통해 조치사항을 분석한 결과 정도관리물질 오류가 62건, 실험과정 오류가 24건, 검사키트 로트번호 관리오류가 18건, 기타 13건으로 분류되었다. 정도관리물질 오류를 방지하고자 개선사항으로 기존에 각 검사자마다 사용하던 방식을 담당자 지정 방식으로 변경하여 모든 검사의 하루 소비량을 분주하여 공동사용을 하였고, 나머지 오류를 방지하고자 검사 전후 모든 과정을 표준화 하여 검사실내 어느 검사자가 시행 하더라도 일원화할 수 있게 하였다. 정도관리물질 오류를 개선한 결과 해동 후 2일 이내 신선한 물질을 사용 가능하였고 같은 물질을 사용하는 검사끼리 비교가 가능해져 물질에 의한 오류인지 명확해짐으로 계통오차 발생원인이 정도관리물질 오류로 기록하는 건수가 줄어들었다. 또한 정도관리물질의 로트번호 변경 시 교체시기가 같아 관리가 용이해졌고, 물질 사용량의 감소로 경제적 효과를 얻을 수 있었다. 그리고 검사표준화 적용 후, 계통오차의 규칙인 22s와 101s의 발생건수가 개선 전 보다 월 평균 2건 이상 줄어드는 결과를 보였다. Multi-rules의 적용을 통한 계통오차의 빠른 확인을 위해 정도관리물질의 체계적인 관리와 목표값과 표준편자의 설정 및 관리가 바탕이 되어야하며, 계통오차 발생 시 검사의 원인분석을 통한 조치사항을 기록하는 것이 중요함을 확인하였다. 본 실험의 결과로 Westgard multi-rules 적용 분석을 통해 발생 오류의 기재와 원인을 효율적으로 분석함으로써 핵의학 검사 내부정도관리의 질적 향상과 정확하고 신속한 결과보고에 기여할 것으로 사료된다. Purpose Westgard multi-rules application based on test quality improvement and commercialized international standard has been widely used in quality control. However, it is difficult to applicate the Westgard multi-rules in nuclear medicine in vitro tests due to the larger sample sizes and the simultaneous measurement of quality control material and patient sample. This study investigated the usefulness of Westgard multi-rules application in nuclear medicine in vitro tests. Materials and Methods A total of 282 systematic error multi-rules (22s, 101s) recorded in the samsung medical center computer system from January 2013 to June 2016 along with 117 cases of corrective measure record was analyzed. The Quality control implementation is recorded in Hospital information system were divided into 4 high-level areas including quality control material error, experimental procedural error, Kit lot number management error, and others. To prevent quality control material error, the existing method that each staff used their own method was changed. The staff who in charge of managing the quality control material was designated and daily consumption amount of every test was strictly controlled by one person. To prevent other errors, every test step was standardized so that the entire test procedures are identically implemented. Results The total quality control implementation was 117 cases; As a result, 62 quality control material errors were 62 cases, experimental process errors were 24 cases, Kit lot number control errors were 18 cases, and other errors were 13 cases. The quality control material error was corrected and could be used fresh materials within 2 days after thawing. The cases of systemic error were decreased to causes as quality control material error. The quality control materials were reduced above 10 vials to a monthly average. In addition, these errors of experimental processing and Kit lot number were improved by test standardization. Consequently, the cases of 101s and 22s in systematic error rules decreased at least 2 cases to a monthly average. Conclusion To confirm of systematic error through multi-rules application quickly, it is necessary to base on management of the QC material, target values and standard deviation. Moreover, in the event of a systematic error, it was found important to record measures based on test cause analysis. The experiment results are expected to contribute to internal quality control improvement and prompt and accurate result reporting through error recording and causal analysis based on Westgard multi-rules analysis.

Feasibility and Reliability of Laser Powder Bed Fused AlSi10Mg/Wrought AA6061 Hybrid Aluminium Alloy Component

Cuiling Zhao,Yuchao Bai,Hao Wang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.4

Laser powder bed fusion (LPBF) provides an effective and economical solution for fabricating multi-material components of complex structures as it entails a layer-wise manufacturing process. The feasibility and reliability of depositing AlSi10Mg alloy on the wrought AA6061 alloy substrate using the LPBF process were studied. The study includes the analysis of metallurgical quality, microstructure evolution, mechanical properties, and corrosion behaviour of the multi-material parts before and after heat treatment. The interface region, decorated with epitaxial growth, shows excellent metallurgical bonding without apparent defects of pores and cracks. LPBF AlSi10Mg comprises fine equiaxed grains and coarse columnar grains on the boundary and inside the molten pool, respectively. They were replaced by large Si particles after heat treatment without altering the grain morphology and <100>//BD (building direction) texture. The as-built multi-material part exhibits a low ultimate tensile strength of 192.8 ± 3.4 MPa, similar to that of wrought AA6061, and a higher elongation (13.6 ± 0.5%) than the LPBF AlSi10Mg alloy (9.4 ± 0.2%). In addition, the ultimate tensile strength and elongation of the multi-material part were slightly improved after heat treatment. Compression testing showed that, in contrast to single-alloy parts, the multi-material part achieved moderate strength and good compressive capacity under both as-built and heat-treated conditions. Interestingly, the galvanic corrosion effects in the interface region are suppressed for both as-built and heat-treated multi-material parts. Moreover, the as-built multi-material sample has a higher corrosion resistance than the heat-treated one. This study verifies the feasibility of efficiently manufacturing a reliable, excellent, and low-cost multi-material component combining conventional and additive manufacturing processes.

Improvement with the Multi-material Decomposition Framework in Dual-energy Computed Tomography: A Phantom Study

Haenghwa Lee,Hee-Joung Kim,Donghoon Lee,Dohyeon Kim,Seungyeon Choi,Minjae Lee 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.6

Dual energy computed tomography (DECT) enhances tissue characterization by obtaining two or three material images from two measurements with different X-ray spectra. Recently, multi-material decomposition (MMD) in DECT has been studied to obtain decomposed material images for more than three basis materials. However, the MMD method is highly sensitive to noise fluctuation due to the direct inversion and the material triplet selection for each pixel. Although several studies have reported to reduce the noise resulting from direct inversion, no studies have researched reduction in the image quality degradation caused by material triplet selection. We proposed a MMD framework for DECT that includes pre-decomposition and post-decomposition stages to reduce image quality degradation due to material triplet selection and direct inversion. The total variation denoising method was applied to the pre-decomposition and the post-decomposition stages as a noise suppression algorithm. The digital phantom, tissue characterization phantom, and Catphan phantom were employed as test objects in this study. The volume fraction accuracy (VFA) and the standard deviation (STD) were quantitatively calculated to evaluate the quality of the decomposed images. The results of the proposed method were compared to those of the direct MMD (DMMD) and the MMD with total variation denoising (MMD-TVD) methods. Compared to the DMMD method, the proposed method improved average the VFA value by 11.40%, 17.31%, and 19.13% in the digital phantom, the tissue characterization phantom, and the Catphan phantom studies, respectively. The STD values for the proposed method are better than those of the DMMD method, and are similar to those of the MMD-TVD method. Our method successfully improved quantification accuracy and suppressed noise. In conclusion, the proposed method resulted in quantitatively better multi-material images for DECT.

NUCLEAR ENERGY MATERIALS PREDICTION: APPLICATION OF THE MULTI-SCALE MODELLING PARADIGM

Samaras, Maria,Victoria, Maximo,Hoffelner, Wolfgang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.1

The safe and reliable performance of fusion and fission plants depends on the choice of suitable materials and an assessment of long-term materials degradation. These materials are degraded by their exposure to extreme conditions; it is necessary, therefore, to address the issue of long-term damage evolution of materials under service exposure in advanced plants. The empirical approach to the study of structural materials and fuels is reaching its limit when used to define and extrapolate new materials, new environments, or new operating conditions due to a lack of knowledge of the basic principles and mechanisms present. Materials designed for future Gen IV systems require significant innovation for the new environments that the materials will be exposed to. Thus, it is a challenge to understand the materials more precisely and to go far beyond the current empirical design methodology. Breakthrough technology is being achieved with the incorporation in design codes of a fundamental understanding of the properties of materials. This paper discusses the multi-scale, multi-code computations and multi-dimensional modelling undertaken to understand the mechanical properties of these materials. Such an approach is envisaged to probe beyond currently possible approaches to become a predictive tool in estimating the mechanical properties and lifetimes of materials.

Magnetic Design Method for Multi-Material Powder Core Inductor to Improve Efficiency of Bidirectional DC/DC Converter within Wide Load Range

J. Imaoka,Y. Ishikura,K. Ito,T. Aoki,M. Noah,M. Yamamoto 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Utilizing powder cores in many power electronics applications have been gaining much attention due to their attractive magnetic properties. However, it is quite challenging for the circuit designer to choose the proper core, as there are many kinds of magnetic powder cores available in the market. Therefore, due to the limitation of a single magnetic material property, it is often difficult to realize high power conversion efficiency within wide load ranges, including light and heavy load conditions. This paper proposes a novel design method of the multi-material inductor which combines multiple powder cores having different material properties. The aim of this work is to provide improved efficiency over the entire load range of power converters. The experimental results have proven that the inductor with multi-material powder cores can improve the efficiency over wide load range. The validity and effectiveness of the proposed magnetic design method are confirmed from theoretical analysis, simulation and experimental tests.

A multi-resolution approach for multi-material topology optimization based on isogeometric analysis

Lieu, Qui X.,Lee, Jaehong Elsevier 2017 Computer methods in applied mechanics and engineer Vol.323 No.-

<P><B>Abstract</B></P> <P>A novel multi-resolution scheme to perform the multi-material topology optimization in the framework of isogeometric analysis (IGA) is proposed. To create high resolution optimized designs with a lower computational cost, a new variable parameter space is supplemented to define design density variables and represent the optimal material distribution utilizing the bivariate B-spline basis functions. These functions are simply obtained by k -refinement strategy in the IGA. The non-uniform rational B-spline (NURBS) basis functions are employed to exactly describe geometric domains and approximate unknown solutions in finite element analysis (FEA) as well. An alternating active-phase algorithm associated with the block Gauss–Seidel method is employed to convert a multiphase topology optimization problem under multiple volume fraction constraints into many binary phase topology optimization sub-problems with only one volume fraction constraint. Accordingly, the number of design variables depends only on one active phase in each of those sub-problems regardless of the number of material phases and is significantly decreased in comparison with the original problem. The Optimality Criteria (OC) method is used as an optimizer to update solutions for such sub-problems. The effectiveness and robustness of the proposed method are verified via testing various benchmark examples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel multi-material multi-resolution topology optimization (MTOP) scheme using isogeometric analysis (IGA) is proposed. </LI> <LI> A new variable parameter space is added to perform IGA-based MTOP. </LI> <LI> The proposed method associated with the alternating active-phase algorithm is presented first. </LI> <LI> Several benchmark problems are tested for validation of the present method. </LI> </UL> </P>

Pillar-supported vacuum insulation panel with multi-layered filler material

Choi, B.,Yeo, I.,Lee, J.,Kang, W.K.,Song, T.H. Pergamon Press ; Elsevier Science Ltd 2016 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.102 No.-

Vacuum insulation panels (VIPs) have about ten times greater insulation performance compared with conventional insulators, and it is highly affected by the filler material. In this paper, pillar-supported vacuum insulation panel is proposed to release the filler material from the pressing load, thereby significantly decreasing the effective thermal conductivity. It is composed of the support structure and the multi-layered filler material. The support structure consists of the cover plates and pillars, as they sustain the atmospheric pressure. Thus, mechanical stability and heat transfer are considered together in the design stage. Multi-pass support (MPS) is introduced to further decrease the conduction through the pillar effectively. Also, the multi-layered filler material is composed of the glass wool sheets and radiation shields of low emissivity. The effective thermal conductivity of the tested specimen measures 1.18mW/mK with vacuum guarded hot plate (VGHP), which shows twice better insulation performance than existing VIPs.

토마토 농약다성분분석 정도관리용 분석표준물질 개발

김종환 ( Jong Hwan Kim ),오영곤 ( Young Gon Oh ),최성길 ( Sung Gil Choi ),홍수명 ( Su Myeong Hong ),김선배 ( Sun Bae Kim ),우인덕 ( In Duk Woo ),김준영 ( Jun Young Kim ),서종수 ( Jong Su Seo ) 한국환경농학회 2016 한국환경농학회지 Vol.35 No.3

BACKGROUND: This study was to develop a analytical reference material including twenty pesticides in tomato. To use it for proficiency test, the suitability of homogeneity, storage stability, assigned values and uncertainty for analytical reference material were important. METHODS AND RESULTS: In order to develop a analytical reference material of tomato for multi-residue analysis of pesticides, twenty-pesticides were treated in tomato and the samples were frozen and homogenized. The homogeneity, stability, assigned value and uncertainty were calculated according to the requirements of the KS A ISO Guide 35, KS Q ISO 13528 and EURL-PT protocol. The values of the within-bottle standard variation(s_wb) and the between-bottle standard variation(s_bb) were 0.9~6.5% of assigned value and the uncertainty(u*_bb)) due to inhomogeneity was also calculated as 0.6~1.9% for all pesticides. This indicated that it was satisfactory to be used as a analytical reference material. The storage stabilities of twenty-pesticides at room temperature and freezing conditions were assessed according to the requirement of the KS Q ISO Guide 35. All pesticides were stable at room temperature (20~30℃) for 8 days and freezing (-20℃) for 23 days. CONCLUSION: The feasibility of analytical reference material for pesticide multi-residue analysis in a tomato matrix was investigated. Homogeneity of within/between-bottle, uncertainty and stabilities at room temperature and freezing condition were satisfactory for a use of proficiency test and quality control. From these results, a analytical reference material would be applicable to monitor the proficiency test of pesticide analysis organizations to improve the reliability and consistency.

Topology optimization with functionally graded multi-material for elastic buckling criteria

Minh-Ngoc Nguyen,Dongkyu Lee,Joowon Kang,Soomi Shin 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.1

This research presents a multi-material topology optimization for functionally graded material (FGM) and nonFGM with elastic buckling criteria. The elastic buckling based multi-material topology optimization of functionally graded steels (FGSs) uses a Jacobi scheme and a Method of Moving Asymptotes (MMA) as an expansion to revise the design variables shown first. Moreover, mathematical expressions for modified interpolation materials in the buckling framework are also described in detail. A Solid Isotropic Material with Penalization (SIMP) as well as a modified penalizing material model is utilized. Based on this investigation on the buckling constraint with homogenization material properties, this method for determining optimal shape is presented under buckling constraint parameters with non-homogenization material properties. For optimal problems, minimizing structural compliance like as an objective function is related to a given material volume and a buckling load factor. In this study, conflicts between structural stiffness and stability which cause an unfavorable effect on the performance of existing optimization procedures are reduced. A few structural design features illustrate the effectiveness and adjustability of an approach and provide some ideas for further expansions.

Parametric design and modeling method of carbon fiber reinforcement plastic-laminated components applicable for multi-material vehicle body development

Lv Tiantong,Chen Zipeng,Wang Dengfeng,Du Xuejing 한국CDE학회 2024 Journal of computational design and engineering Vol.11 No.1

Combined application of steel, aluminum, and carbon fiber reinforcement plastic (CFRP) is the main direction of future lightweight body development. However, the anisotropy and additional lamination design variables of CFRP parts pose significant challenges for the development of multi-material bodies. This study establishes a parametric design method for the variable-thickness lamination scheme based on non-uniform rational B-splines, it can be coupled with existing parametric design methods for structural shapes to formulate a complete parametric design and modeling of CFRP components. On this basis, a homogenized intermediate material property is derived from classic laminate theory by introducing lamination assumptions, it enables a stepwise multi-material body optimization method to solve the challenge that components’ material design variables switching between CFRP and alloy will introduce/eliminate lamination design variables iteratively, posing a great optimization convergence difficulty. The proposed parametric modeling method for CFRP components was validated by experimental tests of a fabricated roof beam, and the proposed optimization method was applied to a vehicle body, achieving 15.9%, 23.9%, 18.6%, and 12.2% increase in bending and torsional stiffness and modal frequencies; 20.2%, 9.3%, and 12.7% reduction of weight and peak acceleration in frontal and side collisions. This study enables the forward design of multi-material bodies compatible with CFRP parts.