• 제목/요약/키워드: FBG,

검색결과 485건 처리시간 0.029초

Strain-based structural condition assessment of an instrumented arch bridge using FBG monitoring data

  • Ye, X.W.;Yi, Ting-Hua;Su, Y.H.;Liu, T.;Chen, B.
    • Smart Structures and Systems
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    • 제20권2호
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    • pp.139-150
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    • 2017
  • The structural strain plays a significant role in structural condition assessment of in-service bridges in terms of structural bearing capacity, structural reliability level and entire safety redundancy. Therefore, it has been one of the most important parameters concerned by researchers and engineers engaged in structural health monitoring (SHM) practices. In this paper, an SHM system instrumented on the Jiubao Bridge located in Hangzhou, China is firstly introduced. This system involves nine subsystems and has been continuously operated for five years since 2012. As part of the SHM system, a total of 166 fiber Bragg grating (FBG) strain sensors are installed on the bridge to measure the dynamic strain responses of key structural components. Based on the strain monitoring data acquired in recent two years, the strain-based structural condition assessment of the Jiubao Bridge is carried out. The wavelet multi-resolution algorithm is applied to separate the temperature effect from the raw strain data. The obtained strain data under the normal traffic and wind condition and under the typhoon condition are examined for structural safety evaluation. The structural condition rating of the bridge in accordance with the AASHTO specification for condition evaluation and load and resistance factor rating of highway bridges is performed by use of the processed strain data in combination with finite element analysis. The analysis framework presented in this study can be used as a reference for facilitating the assessment, inspection and maintenance activities of in-service bridges instrumented with long-term SHM system.

Effects of Physical Activity on Glycemic Control in Type 2 Diabetics (제2형 당뇨병 환자의 신체활동이 혈당조절에 미치는 영향)

  • Choi, Eun-Jin
    • Korean Journal of Adult Nursing
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    • 제23권3호
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    • pp.298-307
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    • 2011
  • Purpose: The purpose of this study was to examine the effects of physical activity on glycemic control among Koreans with type 2 diabetes. Methods: A total of 215 patients with type 2 diabetes (82 male and 133 female) were recruited (mean age = $59.0{\pm}9.7$ years). The amounts of physical activity was assessed using the physical activity scale for elderly (PASE). Fasting blood glucose (FBG), Hemoglobin A1c ($HbA_1c$), and 2 hours post-prandial glucose (2hrPG) were measured. Results: The highest PASE score was housework-related physical activity. However, the amounts of walking was significantly higher in good FBG level (Z = 1.39, p=.041) and the amounts of leisure-time physical activity was higher in good HbA1 and 2hrPG level than in the poor glycemic control group (Z = 2.29, p<.001; Z = 1.99, p=.001). A logistic regression analysis showed that patients with leisure-time physical activity in the top quartile more likely presented with good glycemic control in $HbA_1c$, OR=3.84 (95% Confidence Interval (CI) = 1.65~8.95) and in 2hrPG, OR=4.06 (95%CI = 1.77~9.27), compared to patients in the lowest quartile. Conclusion: Leisure-time physical activity is effective for controlling the glucose levels, especially $HbA_1c$ and 2hrPG among type 2 diabetic patients. It is suggested that health providers need to more focus on providing aggressive recommendations on physical activity considering physical activity patterns by individuals.

The study on Nutritional Management Status of Diabetic Patients in the Health Center (일부지역 보건소 당뇨병 환자의 영양상태와 당뇨병 관리실태)

  • 조경옥
    • Journal of the East Asian Society of Dietary Life
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    • 제5권1호
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    • pp.7-19
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    • 1995
  • This study was conducted to evaluate the nutritional status and diabetes management of diabetic patients in the Health Center. General characteristics, food habits, food intakes and the knowledge about diet therapy were investigated from ninety one diabetes subjects. Anthropometric assessment such as weight, hight, triceps skinfold thickness, and biochemical measurement of fasting blood glucose(FBG), post prandial 2 hours blood glucose(PP2), and hemoglobin A1c(HbA1c) were obtained form the subjects. The results were summarized as following : 1. The average of age was 60.9 years old and 83.5% of subjects was illiterate and primary school graduated. 2. Relative Body Weight(RBW) and % body muscle were 96.18${\pm}$13.6 and 33.56${\pm}$7.01%, respectively. Obese subjects whose body weight exceeded 120% of the ideal values were 3.3%. 3. The 86.8% of subjects were managed by oral hyperglycemic agents. 4. The mean of FBG, PP2, HbA1c were 140.75${\pm}$44.43mg/㎗, 7.60${\pm}$1.88%, respectively. 5. The mean daily intake of calorie was 1407㎉, and 73.6% of subjects lower caloric intake than prescribed calorie. when the degree of dietary compliance was expressed as Tunbridge score, 18.7% of total subjects was grouped as satisfactory, where as 20.9% and 60.4% could be considered as tolerable and hopeless, respectively. The nutrients intake were lower than RDA except for Vitamin A and Vitamin C and the ratio of carbohydrate : protein : fat was 72 : 14 : 14. 6. The mean score of knowledge test about diet therapy was 3.52${\pm}$2.19 out of possible 14.00 points. The above results suggested that the most of diabetic patient showed the poor nutritional status and they faced the lack of knowledge about diabetes management.

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Risk of Fracture Prevalence and Glycemic Control in Korean Older and Middle-aged Patients with Diabetes: A Retrospective Analysis of a Cohort Derived from the Korean National Health Insurance Sharing Service Database, 2009-2013 (노인과 중년 당뇨병 환자의 골절의 발생 빈도 위험과 혈당조절의 관계)

  • Sin, Hye Yeon
    • Korean Journal of Clinical Pharmacy
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    • 제28권3호
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    • pp.194-203
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    • 2018
  • Background: Bone fractures are high in elderly patients with type 2 diabetes mellitus (T2DM). Hyperglycemia and chronic kidney disease may increase the risk of fracture prevalence via altered bone metabolism, but whether glycemic control and kidney function are associated with the risk of fracture prevalence remains unclear. This study evaluated the relationship between glycemic control and baseline estimated glomerular filtration rate (eGFR) and risk of fracture prevalence in older and middle-aged patients with T2DM. Methods: Patients who underwent a general medical check-up between 2009 and 2013 were selected from the Korean National Health Insurance Sharing Service records. Chi-square test and multiple logistic regression analysis were used to assess the relationship between glycemic control and eGFR and risk of fracture prevalence. Results: Cumulative fracture prevalence were higher in patients with T2DM, irrespective of whether they had tight or less stringent glycemic control (fasting blood glucose [FBG] ${\geq}110mg/dL$). After adjustment for baseline age and FBG, tight and less stringent glycemic control was significantly associated with increased adjusted risk of fracture prevalence in middle-aged patients with T2DM (OR=1.13, 95% CI, 1.05-1.21, p=0.0005 vs OR=1.13, 95% CI, 1.06-1.20, p=0.0001), but not in older patients. Baseline eGFR was not significantly related to fracture prevalence in either older or middle-aged patients. Conclusion: Less stringent glycemic control significantly increased the adjusted risk of fracture prevalence in middle-aged patients with T2DM. Further studies are needed to confirm the effect of tight glycemic control on fracture prevalence.

Study of Optical Fiber Sensor Systems for the Simultaneous Monitoring of Fracture and Strain in Composite Laminates (복합적층판의 변형파손 동시감지를 위한 광섬유 센서 시스템에 관한 연구)

  • 방형준;강현규;홍창선;김천곤
    • Composites Research
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    • 제16권3호
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    • pp.58-67
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    • 2003
  • To perform the realtime strain and fracture monitoring of the smart composite structures, two optical fiber sensor systems are proposed. The two types of the coherent sources were used for fracture signal detection - EDFA with FBG and EDFA with Fabry-Perot filter. These sources were coupled to EFPI sensors imbedded in composite specimens. To understand the characteristics of matrix crack signals, at first, we performed tensile tests using surface attached PZT sensors by changing the thickness and width of the specimens. This paper describes the implementation of time-frequency analysis such as short time Fourier transform (STFT) and wavelet transform (WT) for the quantitative evaluation of fracture signals. The experimental result shows the distinctive signal features in frequency domain due to the different specimen shapes. And, from the test of tensile load monitoring using optical fiber sensor systems, measured strain agreed with the value of electric strain gage and the fracture detection system could detect the moment of damage with high sensitivity to recognize the onset of micro-crack fracture signal.

Subtle inflammation: a possible mechanism of future cardiovascular risk in obese children

  • Sontichai, Watchareewan;Dejkhamron, Prapai;Pothacharoen, Peraphan;Kongtaweelert, Prachya;Unachak, Kevalee;Ukarapol, Nuthapong
    • Clinical and Experimental Pediatrics
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    • 제60권11호
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    • pp.359-364
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    • 2017
  • Purpose: The risk of cardiovascular disease (CVD) has been shown to be associated with systemic inflammation in obese adults with metabolic syndrome (MetS). The aims of this study were to evaluate the prevalence of MetS and its relation to inflammatory markers in obese Thai children. Methods: A cross-sectional study was conducted. Children with history of endogenous obesity, chronic diseases, drug ingestion, and any acute illness within 2 weeks prior to enrollment were excluded. Their fasting blood glucose (FBG) levels, oral glucose tolerance tests, insulin, lipid profiles, and selected inflammatory markers, including interleukin-6, tumor necrosis factor-alpha, and high-sensitivity C-reactive protein (hs-CRP) levels, were tested. Results: In this study, 58 obese Thai children (female, 20; male, 38) with a mean body mass index z score of $5.1{\pm}2.2$ were enrolled. The prevalence of MetS and prediabetes was 31% and 17.2%, respectively. None of the children had diabetes. FBG levels, 2-hour glucose levels, and lipid profiles were not statistically different between those with and without MetS. However, obese children with MetS had higher insulin levels and homeostasis model assessment of insulin resistance values. Elevated hs-CRP levels were found in 69% of the cases, although it was not statistically different between the 2 groups. Conclusion: We described a substantial prevalence of MetS in Thai obese children. Regardless of MetS status, two-thirds of the obese children had elevated hs-CRP level, indicating subtle ongoing inflammatory process. This chronic inflammation feasibly predisposes them to CVD in the future, even in children without MetS.

50-GHz AWG Interrogation of a Multiple-FBG Temperature Sensor (50-GHz AWG를 이용한 다중 광섬유격자 브래그 파장 계측)

  • Moon, HyungMyung;Kwak, SeungChan;Kim, JinBong;Yim, Ju-Wan;Park, Dong-Young;Im, Kiegon
    • Korean Journal of Optics and Photonics
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    • 제30권6호
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    • pp.226-229
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    • 2019
  • We investigated an interrogation system for fiber Bragg gratings by using a 50-GHz 96-channel array waveguide grating. Linearity of the sensitivity (the wavelength shift in response to the change in strain or temperature) is achieved for a Bragg grating of sufficiently wide bandwidth. The present wavelength-monitoring system could measure the change in Bragg wavelength with a resolution of 0.01 nm, at intervals of 10 seconds. When this interrogation system was used for a linear array of 12 acrylaterecoated fiber gratings, the wavelength sensitivity changed from 0.018 nm/℃ to 0.01 nm/℃ when the operating temperature changed from -25℃ to 85℃.

Accuracy Improvement of FBG Temperature Sensor System (광섬유격자 온도센서의 정밀도 개선)

  • Lee, Hyun-Wook;Song, Min-Ho;Lee, June-Ho
    • Korean Journal of Optics and Photonics
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    • 제17권3호
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    • pp.216-222
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    • 2006
  • We propose the use of the Gaussian-curve fitting algorithm for the improvement of measurement accuracy in wavelengthscanned Fabry-Perot filter based demodulation systems. The peak locations of FBG sensors were calculated from the fitted curves rather than from distorted PD profiles, resulting in much better measurement accuracy than that of the highest-peak search algorithm. Also, the algorithm was proved to minimize measurement uncertainty of spectrally-distorted grating sensors. From our experimental results, a temperature resolution as small as ${\sim}0.3^{\circ}C$ was readily achieved by use of the Gaussian-curve fitting algorithm whereas the highest-peak search algorithm gave a temperature resolution larger than ${\sim}4^{\circ}C$.

Monitoring of a CFRP-Stiffened Panel Manufactured by VaRTM Using Fiber-Optic Sensors

  • Takeda, Shin-Ichi;Mizutani, Tadahito;Nishi, Takafumi;Uota, Naoki;Hirano, Yoshiyasu;Iwahori, Yutaka;Nagao, Yosuke;Takeda, Nobuo
    • Advanced Composite Materials
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    • 제17권2호
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    • pp.125-137
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    • 2008
  • FBG (Fiber Bragg Grating) sensors and optical fibers were embedded into CFRP dry preforms before resin impregnation in VaRTM (Vacuum-assisted Resin Transfer Molding). The embedding location was the interface between the skin and the stringer in a CFRP-stiffened panel. The reflection spectra of the FBG sensors monitored the strain and temperature changes during all the molding processes. The internal residual strains of the CFRP panel could be evaluated during both the curing time and the post-curing time. The temperature changes indicated the differences between the dry preform and the outside of the vacuum bagging. After the molding, four-point bending was applied to the panel for the verification of its structural integrity and the sensor capabilities. The optical fibers were then used for the newly-developed PPP-BOTDA (Pulse-PrePump Brillouin Optical Time Domain Analysis) system. The long-range distributed strain and temperature can be measured by this system, whose spatial resolution is 100 mm. The strain changes from the FBGs and the PPP-BOTDA agreed well with those from the conventional strain gages and FE analysis in the CFRP panel. Therefore, the fiber-optic sensors and its system were very effective for the evaluation of the VaRTM composite structures.

Evaluation Potential Antidiabetic Effects of Ferula latisecta in Streptozotocin-Induced Diabetic Rats

  • Javanshir, Sajad;Soukhtanloo, Mohammad;Jalili-Nik, Mohammad;Yazdi, Amirali Jahani;Amiri, Mohammad Sadegh;Ghorbani, Ahmad
    • Journal of Pharmacopuncture
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    • 제23권3호
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    • pp.158-164
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    • 2020
  • Objectives: The aim of the present work was to evaluate the possible beneficial effects of F. latisecta on blood glucose, lipids, and diabetes-related changes in the liver and kidney of streptozotocin-induced diabetic rats. Methods: Male Wistar rats were randomly allocated into four groups (n = 6): normal control rats, diabetic control rats, diabetic rats treated for 4 weeks with F. latisecta root (400 mg/kg/day), and diabetic rats treated with F. latisecta aerial parts (400 mg/kg/day). Results: Induction of diabetes significantly (p < 0.05) increased the levels of fasting blood glucose (FBG), triglyceride, total cholesterol, low-density lipoprotein (LDL), blood urea nitrogen (BUN), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Diabetes also increased (p < 0.05) oxidative stress in the kidney and liver (decrease of thiol and increase of superoxide dismutase). The root and aerial parts of F. latisecta significantly reduced the level of LDL (p < 0.05) and restored the content of thiol (p < 0.05) and superoxide dismutase (p < 0.01) in the kidney and liver. F. latisecta had no significant effect on the levels of FBG, BUN, AST, and ALT. The root of F. latisecta also reduced the serum level of total cholesterol (p < 0.05) and prevented the progression of hyperglycemia. Conclusion: These findings suggest that F. latisecta may improve diabetic dyslipidemia by reducing serum LDL. Further studies are needed to confirm our findings.