• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.70-76
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• 2013

The objective of the paper is to present the results of analytical and experimental studies dealing with dynamic load for continuous steel girder bridges due to normal truck traffic. Various bridge design codes specify dynamic load factor (defined as a fraction of static portion of live load) for short span structures at the level of about 0.3. However, there are not definite values specified for continuous brigdes. Therefore, it is an usual practice to use the code specified dynamic load factors for simple span bridges to continuous bridges without clear background. The field measurement results indicate that the actual dynamic load factors are less than 0.2 for a single truck, and less than 0.05 for two trucks side-by-side, regardless of positive and negative moment region.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.139-146
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• 2003

The objective of the presented study is to develop an efficient procedure of proof load testing for existing bridges. By analytical methods, some of these bridges are not adequate to carry normal highway traffic. However, the actual load carrying capacity is often much higher than what can be determined by conventional analysis. Proof load testing can reveal the hidden strength reserve and thus verify the adequacy of the tested bridge. Proof load level required for meaningful tests should be sufficiently higher than legal load. In the state of Michigan, the legal 11-axle truck can weigh up to 685 kN. In this study, a combination of two military tanks and two Michigan 11-axle trucks was used. The proof loads were gradually increased to ensure the safety of the test. After each move, measurements were taken. For the considered bridge, stress levels were rather low compared to pre-test analysis results. This is due to incorrect material strength, structural contribution of nonstructural components such as parapets and railings, and partially fixed supports.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.235-238
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• 1998

This paper presents the detection of internal combustion engine's multiple misfire. The primary cause of air pollution by vehicles is imperfect conbustion of fuel. The CARB(California Air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations requir that misfire should be monitored by the diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by walsh-fourier transform. Experimental work confims that it's possible to apply walsh-fourier transform for the detection of multiple misfires in no-load idle and road testing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.180-187
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• 2009

The objective of this research is to verify the code-specified girder distribution factors (GDF) for continuous steel girder bridges by field testing. Previous analytical study revealed that current GDF's specified in AASHTO Standard and AASHTO LRFD, developed for the simple span bridges are conservative even for the continuous bridges. In this study, field tests were performed for three continuous steel girder bridges to validate the GDF's specified in the AASHTO codes. The results show that the code values are conservative when compared with field tests, and in some cases, too conservative. Also, strains measured from the field test are, in most cases, smaller than those expected from the analytical results. However, when the GDF's from measured strains are compared with GDF's from analysis, it is found that the analysis results are not conservative, and in some instance, the analytical results underestimate the actual GDF's, which can lead to a groundless notion of safety. In one case, test results showed that the code GDF's specified in AASHTO LRFD is too permissive. As a result, it is found that GDF's specified in AASHTO LRFD should be used with careful reservation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.219-229
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• 2003

The objective of this work is to verify the Code specified girder distribution factors for short and medium span bridges. To accomplish this objective, field tests were carried out on seventeen simply supported highway bridges. This paper presents the procedure and results of field tests that were performed to verify girder distribution factors. Finite Element analyses previously performed at the University of Michigan indicated that in most cases currently used girder distribution factors specified in AASHTO Codes are too conservative. However, these studies also showed that for short spans and short girder spacings, the girder distribution factors can be too permissive. Therefore, this paper focused on experimental evaluation of girder distribution factors for short and medium span steel girder bridges. The results were compared with the distribution factors specified by AASHTO Standard (2000) and AASHTO LRFD Code (1998). It has been found that the measured girder distribution factors are lower than AASHTO values in most cases, and sometimes the code specified values are overly conservative. The research work involved formulation of the testing procedure, selection of structure, installation of equipment, measurements, and interpretation of the results.

• Steel and Composite Structures
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• v.18 no.3
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• pp.673-691
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• 2015

In this paper we are particularly focusing on the dynamic crack fatigue life of a 25 m length wind turbine blade. The blade consists of composite materiel (glass/epoxy). This work consisted initially to make a theoretical study, the turbine blade is modeled as a Timoshenko rotating beam and the analytical formulation is obtained. After applying boundary condition and loads, we have studied the stress, strain and displacement in order to determine the critical zone, also show the six first modes shapes to the wind turbine blade. Secondly was addressed to study the crack initiation in critical zone which based to finite element to give the results, then follow the evolution of the displacement, strain, stress and first six naturals frequencies a function as crack growth. In the experimental part the laminate plate specimen with two layers is tested under cyclic load in fully reversible tensile at ratio test (R = 0), the fast fracture occur phenomenon and the fatigue life are presented, the fatigue testing exerted in INSTRON 8801 machine. Finally which allows the knowledge their effect on the fatigue life, this residual change of dynamic behavior parameters can be used to predicted a crack size and diagnostic of blade.

• Tuberculosis and Respiratory Diseases
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• v.62 no.3
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• pp.184-191
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• 2007

Background: For the diagnosis of pleural tuberculosis, polymerase chain reaction (PCR) of pleural effusion specimens has shown very low sensitivity, which might be due to the small number of bacilli in the samples. The purpose of this investigation is to determine whether the sensitivity of PCR testing can be improved when increasing the amount of pleural effusion specimens. Methods: We prospectively analyzed pleural effusion specimens obtained from 53 patients for whom the exclusion of the possibility of tuberculous pleural effusion was necessary. We performed Mycobacterium tuberculosis PCR testing using the Cobas Amplicor MTB test (Roche Diagnostic Systems) with three different amounts (10ml, 25ml, and 50ml) of pleural effusion specimen in each patient. Pleural tuberculosis was defined as having one of the following: culture-positive pleural fluid sample, histopathologic finding consistent with tuberculosis on pleural biopsy, culture-positive sputum specimen, and/or positive response to anti-tuberculous medication without other possible causes of pleural effusion. Results: Of the 53 patients, 26 received the diagnosis of pleural tuberculosis. The sensitivities of AFB smearing, Mycobacterium tuberculosis culture of pleural effusion specimen, pleural biopsy, and measurement of ADA were 3.8%, 15.4%, 84.6%, and 88.5%, respectively. The results of PCR testing were positive for 3 (11.5%), 4 (15.4%), and 3 (11.5%) of the 26 patients when using 10ml, 25ml, and 50ml of pleural effusion specimens, respectively. These results did not show a statistically significant difference in the sensitivity of PCR testing when increasing the amount of pleural effusion samples (p>0.05, symmetry exact test). Conclusion: For specimens such as pleural effusion, in which the bacillary load is very low, the clinical utility of PCR testing seems highly limited with the kits designed for the diagnosis of pulmonary tuberculosis. An increased amount of pleural effusion sample does not improve the sensitivity of PCR testing.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.389-394
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• 2012

In this study, based on IEC 60601-2-54 standard load conditions presented in the limited interval over the air kerma at the absolute linearity closely evaluated by measuring the X-ray results were as follows: 10 units targeted all Diagnostic X-ray generating device (DR) presented in the IEC 60601-2-54 standard linearity of air kerma emerged as inappropriate, the general evaluation of the dose linearity from four in the top 50% and 80 kVp % of the two measurement series were as irrelevant all the rest from six of the top tube voltage of 50% and 80% of the two measurement series, appeared in all suitable. Presented in IEC 60601-2-54 standard dose linearity testing and conventional linearity tests showed many differences. IEC 60601-2-54 standard linearity in the proposed international standards of air kerma is the recommendation of the existing dose linearity considerably more feasible, and to quantify the amount of radiation as the standard suggested by the standard IEC 60601-2-54 air kerma of a diagnostic X-ray imaging device linearity performance management is considered key elements in the critical appraisal.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.67-74
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• 1998

The primary cause of air pollution by vehicles is imperfect combustion of fuel. One of the most usual causes of this imperfect combustion is the misfire in IC engins. The U.S. EPA(Environment Protection Agency) and the CARB(California air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations require that misfire should be monitored by the engine diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Several solutions to the misfire detection problem have been proposed for the detection of misfires. However, the performance of these methods in the presence of misfire is not altogether clear. This paper presents a precise method and system for internal combustion engine misfire. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by WDPT, so that the more reliable misfire detection than the time domain analysis. Experimental work confirms that it is possible to apply the WDFT for the detection of misfires in no-load idle and road testing.