Effect of Summer Sea Level Rise on Storm Surge Analysis

Typhoons occur intensively between July and October, and the sea level is the highest during this time. In particular, the mean sea level in summer in Korea is higher than the annual mean sea level about 14.5cm in the west coast, 9.0 to 14.5cm in the south coast, and about 9.0 cm in the east coast. When the rising the sea level and a large typhoon overlap in summer, it can cause surges and flooding in low-lying coastal areas. Therefore, accurate calculation of the surge height is essential when designing coastal structures and assessing stability in order to reduce coastal hazards on the lowlands. In this study, the typhoon surge heights considering the summer mean sea level rise (SH_m) was calculated, and the validity of the analysis of abnormal phenomena was reviewed by comparing it with the existing surge height considering the annual mean sea level (SH_a). As a result of the re-analyzed study of typhoon surge heights for BOLAVEN (SANBA), which influenced in August and September during the summer sea level rise periods, yielded the differences of surge heights (cm) between SH_a and SH_m 7.8~24.5 (23.6~34.5) for the directly affected zone of south-west (south-east) coasts, while for the indirect south-east (south-west) coasts showed -1.0~0.0 (8.3~12.2), respectively. Whilst the differences between SH_a and SH_m of typhoons CHABA (KONG-REY) occurred in October showed remarkably lessened values as 5.2~ 14.2 (19.8~21.6) for the directly affected south-east coasts and 3.2~6.3 (-3.2~3.7) for the indirectly influenced west coast, respectively. The results show the SH_a does not take into account the increased summer mean sea level, so it is evaluated that it is overestimated compared to the surge height that occurs during an actual typhoon. Therefore, it is judged that it is necessary to re-discuss the feasibility of the surge height standard design based on the existing annual mean sea level, along with the accurate establishment of the concept of surge height.

Experimental verification of punching shear resistance of flat slab fragments

The paper deals with the loading test results of an experimental reinforced concrete flat slab fragment, which was supported by an elongated rectangular column. The slab specimens were 200 mm thick and were designed without any shear reinforcement. By experimentally obtained punching shear resistance, the accuracy of the standard design models for prediction punching resistance was compared. The results of the experiments were also compared with the results of a numerical non-linear analysis performed in the Atena program.

Research and Development of Real-time High-precision GNSS Receivers: A Feasible Application for Surveying and Mapping in Vietnam

In recent years, the Global Navigation Satellite System (GNSS) has been widely applied insurveying and mapping. Currently, in Vietnam, dual-frequency GNSS receivers are quite extensivelyapplied with the real-time kinematic (RTK) measurement technique using a continuously operatingreference station network. However, high-accuracy GNSS receivers are often expensive, sometimes notmeeting the needs of users for specific applications. This research develops two types of low-cost highprecisionGNSS receivers for RTK positioning for different purposes. First, the millimeter precisionGNSS receiver used in real-time displacement monitoring is based on Trimble's BD970 mainboardtechnology and some other modules. These components are interconnected according to a standarddesign scheme and assembled in an enclosure to form a GNSS receiver. In addition, a GNSS datatransmission in the National Marine Electronics Association standard format by Networked Transport ofRadio Technical Commission for Maritime Services via Internet Protocol (NTRIP) has beendesigned and developed. The GNSS receiver after development is loaded with program code written inthe C# programming language, using the Arduino programming tool. Second, the GNSS receivers havethe centimeter accuracy for RTK positioning used in surveying and mapping based on U-blox'smainboard technology and some other modules. These modules are also connected together according toa standard design scheme and assembled in an enclosure to form a complete GNSS receiver. Theevaluation results show that the designed and developed GNSS receivers completely meet therequirements of surveying and mapping in coal mines in Vietnam, such as real-time monitoring oflandslides, surveying and topographical mapping and other surveying works to serve the mining process.

Reliability Quantification of Railway Electrification Mast Structure Considering Buckling

This paper aims to quantify and assess the reliability of mast structures as a part of ensuring structure safety. The mast structure is a basic aspect of the overhead line electrification equipment (OHLE) used in railway systems. This structure is very important as the failure of structure leads to the failure of an electric system that supplies the power to the train. To ensure structural safety and reliability, this paper thus analyses the reliability index of the mast, stay tube, and bracket tube structures. According to Eurocode, buckling resistance under compression of these parts were calculated based on specific material properties, and the load condition of these structures is based on Australian Railcorp document TMC331. In this paper, the strength load combination with the wind loading on the wire at 45° on the track is considered in particular as being the worst load combination for structures to bear, and the random variables used to affect reliability probabilistic analysis. Various parameters including self-weight, wind load, dimension parameters, materials, geometrical properties are taken into consideration. Statistical models of these parameters are taken from previous studies. The reliability index value was calculated via quantification of structure reliability using the first-order reliability method (FORM). Finally, a sensitivity analysis is used to evaluate the impacts of yield strength, length, cross-section, density, and load combination on reliability. The obtained results show that increasing length of structure can potentially reduce the reliability of mast structure to buckling resistance while the density of material also plays a major role in the reliability index. The findings will provide the structural safety criteria of the railway mast structure and improve the standard design to mitigate the risks and unplanned maintenance due to the uncertainties.

Динамическая коррекция чувствительности дефектоскопических каналов при высокоскоростном контроле рельсов

The article is aimed at increasing the reliability of high-speed ultrasonic monitoring of long-dimensional objects, in particular, railway rails. The technical documentation for the control does not take into account the features of high-speed rail monitoring, is focused on compliance with the initially set parameters and cannot provide the required reliability of defect detection. The factors that manifest themselves at high scanning speeds and negatively affect the quality of control are considered. Most of these factors cannot be quantified and accounted for in order to adjust the control parameters. An estimate of the number of undetected defects was made when working according to current documents. To ensure reliable control at high speeds, it is proposed to evaluate the current sensitivity of the control using signals from standard design reflectors of the controlled object. As such reflectors, when monitoring rails, it is proposed to use standard holes in the area of bolted joints that are regularly encountered along the scanning path. An expression is obtained for determining the value of the correction of the control sensitivity depending on the scanning speed and the measured size of the signals from the holes. An algorithm for dynamic adjustment of the parameters (sensitivity) of the control is proposed, which increases the reliability of detecting defects in high-speed scanning conditions.

Planar kinematic grids created on the basis of triangulation

Activities to protect historic cities and the revival of areas of historical importance are accompanied by a desire to maximize the entry of the natural environment into the city. Architects and builders often go on the use of non-standard design solutions to create a beautiful, healthy, beloved city. They widely use spatial coating constructions as the forms closest to natural. Construction with curvilinear outlines, that V.G. Shuhov had invented and patented in XIX century, had become the basis of modern architecture. The reticulated shells have unlimited possibilities for creating new architectural forms. The growing number of structures constructed using this technology indicates the prospects for the use of such structures, especially at low temperatures, in seismic and remote areas. The design of reticulated shells is self-supporting and has higher bearing properties compared to other types of structures. This is due to the uniform distribution of loads on all the rods of the structure, which virtually eliminates brittle fracture. The aerodynamic shape of the reticulated shells provides the best wind flow compared to other structures, which makes them stable during destructive hurricanes and tornadoes.

Diagnostic Accuracy of Ultrasonography for Detection of AT by Taking Surgical Findings as Gold Standard

Objective: To assess the diagnostic accuracy of ultrasonography for detection of Achilles tendinopathy by taking surgical findings as gold standard. Design of the Study: It was a descriptive cross-sectional study. Study Settings: This study was carried out at Department Of Diagnostic Radiology And Diagnostic Imaging Combined Military Hospital, Lahore from 23rd December 2017 to 22nd June 2018. Material and Methods: A total of 70 patients of age 20-70 years, of either gender presenting with severe pain and swelling in area of Achilles tendon were included. Patients with heel pain having concurrent heel ulcer, eczematous changes or calcaneal fractures, muscular dystrophy and previous surgery were excluded. All the patients were then underwent ultrasonography and findings were noted for presence or absence of Achilles tendinopathy. Each Ultrasonographic finding were compared with surgical findings. Results of the Study: Mean age was 41.24 ± 10.34 years. Out of these 70 patients, 46 (65.71%) were male and 24 (34.29%) were females with male to female ratio of 1.9:1. In USG positive patients, 40 (True Positive) had Achilles tendinopathy and 04 (False Positive) had no Achilles tendinopathy on surgical findings. Among, 26 USG negative patients, 03 (False Negative) had Achilles tendinopathy on surgical findings whereas 23 (True Negative) had no Achilles tendinopathy on surgical findings. Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of ultrasonography for detection of Achilles tendinopathy by taking surgical findings as gold standard was 93.02%, 85.19%, 90.91%, 88.46% and 90.0% respectively. Conclusion: This study concluded that diagnostic accuracy of ultrasonography for detection of Achilles tendinopathy is quite high. Keywords: Achilles tendinopathy, ultrasonography, sensitivity.

Sedimentation Tanks for Treating Rainwater: CFD Simulations and PIV Experiments

The removal of solids is the most important step when treating rainwater. The article evaluates two designs of sedimentation tanks that can be used for the continuous separation of fine particles from water: OS—standard sedimentation tanks, and OW—swirl sedimentation tanks. The tanks were studied by conducting computational fluid dynamics (CFD) modeling and particle image velocimetry (PIV) experiments. The settling process in sedimentation tank was carried out at varying operating flow rates. A tank with a modified structure was used for the tests, where water was supplied by a nozzle placed at an angle. This solution made it possible to obtain a rotational flow that transported the suspended particles towards its wall, where downward axial velocity resulted in the settling of particles. Based on the research, it was observed that the flow patterns showed inward flow at the bottom of the tank and an upward flow and the lifting of the settled particles near the hatch at the bottom. The presented experimental measurements provided detailed insight into flow patterns, and valuable calibration and verification data for further CFD modeling. Traditional PIV techniques are useful in the case of standard design, whereas CFD is invaluable for supporting this work and for investigating the design of novel sedimentation tanks.

Modelling and Simulation of Soft Robotic Human Tongue with Improved Motion

There is a huge demand for electronic tongues in the food and pharmaceutical industries for chemical detection and flavor analysis. The lack of availability of robots with electronic tongues has motivated us to investigate, design and simulate a human tongue's complex motions. Human anatomy was studied in detail to modify the standard design of the human tongue, with the addition of embedded chambers at strategic locations, to replicate various 3D motions (rolling, groove, twist, and elongation) of the human tongue necessary for improving the bio-chemical sensing capabilities. The FEM (Finite element method) simulations showed the relation between pressure and deformation range for various kinds of motions in a human tongue, including the mechanical properties from the stress versus strain response.

Climate change impacts on intensity duration frequency curves of precipitation: A case study of Shiraz synoptic station, Iran

Intensity-duration-frequency (IDF) curves are among the standard design tools for many engineering applications such as urban drainage management. Since climate change may considerably affect precipitation, updating of IDF curves is highly necessary. The present study aims to examine the impacts of climate change on IDF curves of Shiraz synoptic station using downscaled outputs of Hadcm3 AOGCM under various emission scenarios (A1B, A2,B1) applying larswg-5 model for the period of 2046 to 2065. The fitted Gumbel distribution was used to estimate the maximum short-term precipitation quantiles in the base period (1968-2000) and the verified empirical Bell type equation was used for the future period. The results show that the mean of maximum daily precipitation and annual precipitation will decrease in the future. Also, the maximum precipitation intensities up to 60 min duration will reducefrom 0.15 mm hr-1 to about 10.79 mm hr-1 compared to the observed period in all returns periods and various scenarios. Overall, there were no tangible changes in intensities for durations higher than 60 min. The highest reduction in precipitation intensity would be at the 20 min duration with 100-year return period in the A2 scenario.