• Corrosion Science and Technology
• /
• 제14권6호
• /
• pp.280-287
• /
• 2015

The German Guidelines for stainless steel in buildings (Z.30.3-6) issued by the German Institute for Building Technology (DIBt) categorizevarious stainless steel grades into five corrosion resistance classes (CRCs). Only 21 frequently used grades are approved and assigned to these CRCs. To assign new or less commonly used materials, a large program of outdoor exposure tests and laboratory tests is required. The present paper shows theresults of stress corrosion cracking (SCC) tests that can distinguish between different CRCs. Slow strain rate tests (SSRT) were performedin various media and at different temperatures. CRC IV could be distinguished from CRC II and CRC III with a 31.3 % $Cl^-$ as $MgCl_2$ solutionat $140^{\circ}C$. CRC II and CRC III could be differentiated by testing in a 30% $Cl^-$ as $MgCl_2$ solutionat $100^{\circ}C$.

• 소음진동
• /
• 제9권5호
• /
• pp.891-898
• /
• 1999

The purpose of Superconducting Magnetic Bearing Flywheel Energy Storage System (SMB-FESS) is to store unused nighttime electricity until it is needed during daytime. An analytical model of the SMB-FESS is necessary to identify the system behavior. At first, we have to model the superconducting magnetic bearing. Modeling the SMB is same as estimating the bearing parameter. The theoretical modal parameter is calculated through the equation of motion and the experimental modal parameter is estimated through the impact testing (modal testing). The bearing parameter is searched by using the non-linear least square method until the theoretical result corresponds to the experimental result. The suggested modeling method is verified by comparing experimental and analytical frequency response function.

• Steel and Composite Structures
• /
• 제1권4호
• /
• pp.441-458
• /
• 2001

We analyzed the experimental and theoretical behavior of a particular type of steel joint designed to connect beam to beam and able to transfer both shear forces and bending moments. This joint is characterized by the use of steel plates and bolts enclosed in the width of the beams. The experimental investigation was carried out characterizing the constituent materials and testing in flexure beams constituted by two portions of beams connected in the middle with the joint proposed. Connections having different characteristics in terms of thickness of plates, number and type of bolts were utilized. Flexure tests allow one to determine the loaddeflection curves of the beam tested and the moment-rotation diagrams of the connections, highlighting the strength and the strain capacity of the joints. The proposed analytical model allows one to determine the moment-rotation relationship of the connections, pointing out the influence of the principal geometrical and mechanic characteristics of single constituents on the full properties of the joint.

• Structural Engineering and Mechanics
• /
• 제59권4호
• /
• pp.703-718
• /
• 2016

Masonry arch bridges present a large segment of Iranian railway bridge stock. The ever increasing trend in traffic requires constant health monitoring of such structures to determine their load carrying capacity and life expectancy. In this respect, the performance of one of the oldest masonry arch bridges of Iranian railway network is assessed through field tests. Having a total of 11 sensors mounted on the bridge, dynamic tests are carried out on the bridge to study the response of bridge to test train, which is consist of two 6-axle locomotives and two 4-axle freight wagons. Finite element model of the bridge is developed and calibrated by comparing experimental and analytical mid-span deflection, and verified by comparing experimental and analytical natural frequencies. Analytical model is then used to assess the possibility of increasing the allowable axle load of the bridge to 25 tons. Fatigue life expectancy of the bridge is also assessed in permissible limit state. Results of F.E. model suggest an adequacy factor of 3.57 for an axle load of 25 tons. Remaining fatigue life of Veresk is also calculated and shown that a 0.2% decrease will be experienced, if the axle load is increased from 20 tons to 25 tons.

• 월간산업보건
• /
• 제9호통권245호
• /
• pp.40-41
• /
• 2008

• 분석과학
• /
• 제9권1호
• /
• pp.118-121
• /
• 1996

56.2% of Aldrich HA was recovered from water by XAD-8 and AGMP-50 procedure. With this method, 0.58mg/l of HA was determined in the water collected from irrigation reservoir near Tae Dok Science Town. For the removal of ash from Aldrich HA, centrifugation was simple, but as effective as dialysis. Neither centrifugation nor dialysis removed Na at all. Only with XAD-8 and AGMP-50 procedure, Na and ash were completely removed.

• Steel and Composite Structures
• /
• 제9권3호
• /
• pp.223-237
• /
• 2009

The present research aims to develop a methodology to rapidly assess bridges with damage to the superstructure, caused by overheight trucks or lower-than-average overhead clearance. Terrestrial laser scanning and image processing techniques are combined with the finite element method to arrive at an analytical model which is more accurate, with respect to the complex geometrical aspects of the bridge in its damaged configuration. ""Virtual load testing"" may subsequently be carried out on this analytical model to determine the reserve capacity of the structure in an objective manner.

• 분석과학
• /
• 제23권3호
• /
• pp.247-254
• /
• 2010

본 연구는 폐기물분석전문기관이 신뢰성 있는 분석결과를 얻을 수 있도록 하기위한 폴리 염화바이페닐(PCBs) 정도관리 숙련도 평가용 표준물질을 개발할 목적으로 수행하였으며 다음과 같은 결과를 얻었다. PCBs함유 절연유와 PCBs가 함유되지 않은 절연유(PCB free oil)에 PCBs 표준액을 첨가하여 조제한 표준물질로 PCBs에 대한 숙련도평가용 표준물질을 제조하였다. PCBs 표준액 첨가에 의한 균질화도를 검토한 결과, Arochlor 1254 (6 ppm)과 Arochlor 1254:1260(1:1) (5 ppm)을 첨가한 경우 최대 60일, Arochlor 1260 (3.5 ppm)을 첨가한 경우 최대 90일이 지나야 균질화되는 것을 확인할 수 있었다. 제조된 표준물질을 10회 이상 반복 측정한 결과, PCBs 제조 표준물질은 상대표준편차 3.51~5.01%로 균질성이 있다고 판단되었으며, 일원분산분석법(one way ANOVA)에 따라 균질도를 평가한 결과 모든 시료가 균질하다고 판단되었다. 제조된 표준물질을 무작위로 10개의 선정하여 분석한 결과를 기준값으로 선택하였으며, 측정과정과 균질도에 의한 확장불확도값은 0.26~0.49로 조사되었다.

• 농약과학회지
• /
• 제15권4호
• /
• pp.529-544
• /
• 2011

분석표준화 관련 국제기관인 ISO, CIPAC 등은 농약제품 시험기관에 대한 정도관리(QC), 숙련도 시험 및 분석법 검증을 수행하기 위한 요구조건을 지침서로 제시하고 있다. 일반적으로, 숙련도 시험은 시험기관의 분석능력 평가를 위하여 시험기관간 비교시험을 바탕으로 시험기관의 수행능력과 기술능력 정도를 판단할 수 있다. 분석법 검증 절차는 정도관리(QC)에서 중요한 단계 중 하나로 특이성, 선택성, 직선성 등의 항목들이 포함되며, 대부분의 국제기관이 농약제품 중 주요성분에 대한 정량분석법에서 재현성, 정확성 및 정밀성 등을 요구하고 있다. 본 연구에서는 농약 이화학시험 분석기관의 시험연구과정 및 결과에 대한 신뢰성을 높이기 위해 국내 외 정도관리에 관한 지침서를 비교 검토하여 국제적으로 표준화된 지침서에 적합한 구체적이고, 효율적인 농약 이화학시험 분석기관의 농약분석법 검증절차 및 시험기관 정도관리 체계(안)를 제안하고자 한다.

• 한국물환경학회지
• /
• 제30권6호
• /
• pp.632-637
• /
• 2014

Proficiency testing by interlaboratory comparisons is used to determine the performance of individual laboratories. In order to verify the quality of acute toxicity testing with Daphnia magna, National Institute of Environmental Research in South Korea is regularly organizing interlaboratory comparisons to estimate the analytical accuracy of different laboratories. Total 58 laboratories located in South Korea took part in interlaboratory proficiency testing scheme with three proficiency testing samples. TU(Toxic Unit) values of each laboratory were determined and robust z-score was calculated in order to evaluate the proficiency levels. Based on the robust z-score classification, 74% of the participant laboratories showed a satisfactory performance (43 laboratories). The main reason of 'unsatisfactory' performance seemed to be considered that the unsuitable management of test organism incubation system and the lack of experience on the identification of the test organism condition by effect of toxicity.