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RISS 인기검색어
- 검색키워드
- 저자 : Mustafa Gul (검색결과 15 건)
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Structural monitoring of movable bridge mechanical components for maintenance decision-making
Gul, Mustafa,Dumlupinar, Taha,Hattori, Hiroshi,Catbas, Necati Techno-Press 2014 Structural monitoring and maintenance Vol.1 No.3
This paper presents a unique study of Structural Health Monitoring (SHM) for the maintenance decision making about a real life movable bridge. The mechanical components of movable bridges are maintained on a scheduled basis. However, it is desired to have a condition-based maintenance by taking advantage of SHM. The main objective is to track the operation of a gearbox and a rack-pinion/open gear assembly, which are critical parts of bascule type movable bridges. Maintenance needs that may lead to major damage to these components needs to be identified and diagnosed timely since an early detection of faults may help avoid unexpected bridge closures or costly repairs. The fault prediction of the gearbox and rack-pinion/open gear is carried out using two types of Artificial Neural Networks (ANNs): 1) Multi-Layer Perceptron Neural Networks (MLP-NNs) and 2) Fuzzy Neural Networks (FNNs). Monitoring data is collected during regular opening and closing of the bridge as well as during artificially induced reversible damage conditions. Several statistical parameters are extracted from the time-domain vibration signals as characteristic features to be fed to the ANNs for constructing the MLP-NNs and FNNs independently. The required training and testing sets are obtained by processing the acceleration data for both damaged and undamaged condition of the aforementioned mechanical components. The performances of the developed ANNs are first evaluated using unseen test sets. Second, the selected networks are used for long-term condition evaluation of the rack-pinion/open gear of the movable bridge. It is shown that the vibration monitoring data with selected statistical parameters and particular network architectures give successful results to predict the undamaged and damaged condition of the bridge. It is also observed that the MLP-NNs performed better than the FNNs in the presented case. The successful results indicate that ANNs are promising tools for maintenance monitoring of movable bridge components and it is also shown that the ANN results can be employed in simple approach for day-to-day operation and maintenance of movable bridges.
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Naeemullah,Mustafa Tuzen,Tasneem Gul Kazi 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-
Simple, rapid and miniaturized portable micropipette tip-syringe solid phase microextraction methodwas developed for speciation of vanadium in water and food samples. Tetra ethylene pentaminefunctionalized multiwalled carbon nanotubes were synthesized and packed in micropipette tip-syringesystem. The surface morphology of adsorbent was characterized, and the effective factors that influencethe efficiency of developed method such as pH, amount of adsorbent, concentration of acid solution fordesorption cycles were studied. The V(V) could be adsorbed on the modified adsorbent surface with tetraethylene pentamine, while V(IV) could not be retained. The assay of V(IV) was based on subtractingvalues of V(V), from total vanadium. The extracted total vanadium and V(V) were injected directly intothe electrothermal atomic absorption spectrometry for analysis. Enhancement factor and detection limitwere found 50 and 0.008 mg L 1, respectively. Accuracy of the method was checked by analysis of certifiedreference materials. The developed method was applied to water and food samples.
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Naeemullah,Tasneem Gul Kazi,Mustafa Tuzen 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-
A novel, simple and rapid single and multi-step cloud point extraction procedure was developed for theselective and simultaneous preconcentration of silver, cadmium and nickel in real samples prior to theirdetermination by flame atomic absorption spectrometry. Dithizone was used as neutral hydrophobiccomplexing agent. Separation of understudy metals can be achieved by controlling the pH value of theextraction system. Evaluation of the two CPE methods was checked by paired t-test, which indicated anon-significant difference. It was successfully applied to the real water sample. Certified referencematerials were used for the accuracy of the green extraction methods. The regression equation for thecalibration curve was linear in the range of 10–150 mg L 1 for Ag, 5–100 mg L 1 for Cd, 10–200 mg L 1 forNi. Relative standard deviation (RSD%) values were found to be lower than 2.5% for all elements. Enhancement factor (EF) and limit of detection (LOD) values were found in the range of 41–58 and 0.27–1.12 mg L 1, respectively.
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Malekzadeh, Masoud,Gul, Mustafa,Kwon, Il-Bum,Catbas, Necati Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.5
Multivariate statistics based damage detection algorithms employed in conjunction with novel sensing technologies are attracting more attention for long term Structural Health Monitoring of civil infrastructure. In this study, two practical data driven methods are investigated utilizing strain data captured from a 4-span bridge model by Fiber Bragg Grating (FBG) sensors as part of a bridge health monitoring study. The most common and critical bridge damage scenarios were simulated on the representative bridge model equipped with FBG sensors. A high speed FBG interrogator system is developed by the authors to collect the strain responses under moving vehicle loads using FBG sensors. Two data driven methods, Moving Principal Component Analysis (MPCA) and Moving Cross Correlation Analysis (MCCA), are coded and implemented to handle and process the large amount of data. The efficiency of the SHM system with FBG sensors, MPCA and MCCA methods for detecting and localizing damage is explored with several experiments. Based on the findings presented in this paper, the MPCA and MCCA coupled with FBG sensors can be deemed to deliver promising results to detect both local and global damage implemented on the bridge structure.
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Sensor clustering technique for practical structural monitoring and maintenance
Celik, Ozan,Terrell, Thomas,Gul, Mustafa,Catbas, F. Necati Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.2
In this study, an investigation of a damage detection methodology for global condition assessment is presented. A particular emphasis is put on the utilization of wireless sensors for more practical, less time consuming, less expensive and safer monitoring and eventually maintenance purposes. Wireless sensors are deployed with a sensor roving technique to maintain a dense sensor field yet requiring fewer sensors. The time series analysis method called ARX models (Auto-Regressive models with eXogeneous input) for different sensor clusters is implemented for the exploration of artificially induced damage and their locations. The performance of the technique is verified by making use of the data sets acquired from a 4-span bridge-type steel structure in a controlled laboratory environment. In that, the free response vibration data of the structure for a specific sensor cluster is measured by both wired and wireless sensors and the acceleration output of each sensor is used as an input to ARX model to estimate the response of the reference channel of that cluster. Using both data types, the ARX based time series analysis method is shown to be effective for damage detection and localization along with the interpretations and conclusions.
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Sumaira Khan,Tasneem Gul Kazi,Mustafa Soylak 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-
An in-syringe ionic liquid-based single step microextraction has been analytically presented. 1-butyl-3-methylimidazolium hexafluorophosphate as extractant and Triton X-100 as dispersing medium wereused. Cd-Dithizone was extracted within a syringe. The effects of some variables such as [C4mim][PF6]volume, pH, TX-100 volume, dithizone concentration, incubation time, diluents nature and matrix effectwere investigated. The limit of detection and preconcentration factor were found as 0.35 mg L 1 and 50,respectively. The validity was checked by using certified reference materials. The relative standarddeviation (RSD) was 4.2%. The method was satisfactorily applied to preconcentration of cadmium innatural water samples.
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M. Ertugrul Kafali,Mehmet Gul,Husnu Alptekin,Mustafa Sahin,Hatice Toy,Mehmet Akoz 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.82 No.5
Purpose: The efficacy of octreotide in the treatment of acute pancreatitis is controversial. Octreotide treatment for acute pancreatitis often shows poor correlation between results obtained in experimental studies and results of clinical trials. In a clinical setting, there is always a delay between the onset of the disease and initiation of the octreotide treatment. The aim of this study is to investigate the relationship between the beginning of treatment and alteration in effectiveness of octreotide. Methods: Acute pancreatitis was induced by pancreatic duct ligation in 50 rats. The rats were randomly divided into five groups. Octreotide was not used in group 1 (control group). Only single dose (4 ㎍/㎏) octreotide was administered subcutaneously to rats in group 2, having induced pancreatitis. Octreotide treatment was begun at different times (8th, 24th, 48th hour) in three other groups and continued treatment at a dosage of 4 μg/kg t.i.d. The animals were sacrificed at the end of the 72nd hour and blood and tissue samples were collected. Results: Leukocyte count and plasma amylase values were less in groups 2 and 3. Hemorrhagic focuses were encountered less at pancreas tissues in group 3. Pancreatic necrosis and alveolar capillary basal membrane damage were lower in groups 3 and 4. No difference was found in fasting blood glucose, calcium and hematocrit. Conclusion: Octreotide had benefical effects in acute pancreatitis when octreotide treatment was begun in the first 24 hours.
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Asma Akhtar,Tasneem Gul Kazi,Hassan Imran Afridi,Mustafa Khan,Muhammad Bilal,Noman Khan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.59 No.-
A modified cloud point extraction method (m-CPE) was developed for the speciation of chromium species (Cr3+ and Cr6+) in artificial saliva extracts (ASE) of snuff products. In this method, Cr3+ was complexed with 8-hydroxyquinoline, which was trapped in nonionic surfactant (Triton X-114), prior to analyzed by electrothermal atomic absorption spectrometer (ETAAS). Whereas, the total extractable Cr was determined by reducing Cr6+ to Cr3+ using Na2SO3 as a reducing reagent. Several parameters were optimized for the developed m-CPE. Under the most favorable conditions, enrichment factor, enhancement factor and limit of detection for the proposed method were 60, 134 and 0.04 μg L−1, respectively having relative standard deviation <5%. Health risks associated with the intake of total Cr in snuff products was also assessed. Estimated daily intake of Cr via sniffing 10 g/day of dry and moist snuff products was found below the maximum tolerable daily intake whereas the calculated risk for cancer due to Cr was observed in the acceptable range of 10 E−6–E−4.
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