Using optical fibers (OF) to control the stress-strain state of steel structures subject to fatigue failure

The article presents the results related to developing and practical testing the method of monitoring the stress strain state of steel structures of mine hoisting machines. Certain positive properties of optical fibers make it possible to use them for measuring the stress-strain state of steel structures. An optical fiber of the ITU-T G.652.D standard is used as a sensor. The analysis and review of the current state of development of fiber-optic conductors is performed. The proposed method of non-destructive testing the stress-strain state of metal structures is capable of providing continuous measurements in real time. The proposed method is universal and suitable for monitoring the stress-strain state of any metal structures subject to fatigue failure

Research of mechanical stress at tension of quartz optical fiber (QOF)

The article presents the results of a study of the process of occurrence of mechanical stress and strain during stretching of a quartz optical fiber. The analysis and review of the current state of development of fiber-optic conductors is performed. The problems of occurrence of microcracks in the body of optical fibers during mechanical loading during operation are considered. In the process of winding optical fibers and further operation, cracks occur. The conducted research allows us to solve an important production problem related to increasing the strength of optical fibers and reducing the number of microcracks. The object of scientific research is quartz optical fiber of the G652 standard, used for the production of fiber-optic cables. For optical fibers, the greatest danger is the stretching, which is observed when rewinding the fiber, during its cabling, during the laying and operation of the optical cable. It was found that the mechanical tensile strength of G652 optical fiber was from 4 482 to 4 808 MPa, and the number of cracks and their parameters affect the tensile strength of the fiber

Using optical fibers (OF) to control the stress-strain state of steel structures subject to fatigue failure

The article presents the results related to developing and practical testing the method of monitoring the stress strain state of steel structures of mine hoisting machines. Certain positive properties of optical fibers make it possible to use them for measuring the stress-strain state of steel structures. An optical fiber of the ITU-T G.652.D standard is used as a sensor. The analysis and review of the current state of development of fiber-optic conductors is performed. The proposed method of non-destructive testing the stress-strain state of metal structures is capable of providing continuous measurements in real time. The proposed method is universal and suitable for monitoring the stress-strain state of any metal structures subject to fatigue failure

Validation of Pipelle endometrial biopsy in patients with abnormal uterine bleeding in Kazakhstani healthcare setting

Background: Abnormal uterine bleeding is a common sign which cover various conditions e/o pathologies. Different approaches are used to evaluate this condition. The aim of this study was to investigate the validity of Pipelle biopsy for endometrial sampling in Kazakhstani women with abnormal uterine bleeding. For this reason, we carried out a prospective study of 120 patients who underwent endometrial sampling due to abnormal uterine bleeding in a tertiary hospital setting in Kazakhstan. Methods: Statistics included descriptive analysis to evaluate the frequency of various endometrial conditions. The validity of Pipelle biopsy sampling was calculated by estimating sensitivity, specificity, accuracy, and positive and negative predictive values. For the Pipelle sampling validity assessment, we analyzed 120 samples, as 21 patients with insufficient samples were excluded. Results: Overall, concordance in histopathologic results was 92.93%. Pipelle sampling identified two cases of adenocarcinoma in our group. Moreover, endometrial hyperplasia was detected with 71.43% sensitivity, 98.82% specificity, PPV of 90.91% and NPV of 95.45%. However, the Pipelle reliability was low in cases of endometrial polyps. In conclusion, the Pipelle method was found to be valid for the diagnosis of endometrial hyperplasia and adenocarcinoma with high SN, SP, PPV and NPV. Conclusions: The Pipelle technique for evaluation of abnormal uterine bleeding in the Kazakhstani health care setting is a useful method with the highest efficacy in ruling out endometrial hyperplasia and diagnosing adenocarcinoma. If endometrial polyp was suspected under ultrasound scan in patients with abnormal uterine bleeding, physicians should consider other tools for endometrial sampling