Potential structural deficiencies within the Gokteik Viaduct Railway Bridge in Upper Burma

This article identifies potential structural deficiencies and safety concerns pertaining to the Gokteik Viaduct railway bridge in Shan State, Burma. The colossal Gokteik Viaduct, which spans 2260 ft and boasts of a superstructure height of 320 ft, was constructed by an American steel company under British contract with the intent of expanding the Burma Railway into Yunnan, China at the beginning of the twentieth century. The author investigates the historical aspects of the Gokteik Viaduct and summarises structural concerns related to the technical design, quality of construction, weathering and wartime damages sustained during the Burma Campaign. The author concludes that an in-depth structural inspection is necessary to ensure the future safety of train passengers.

Application of UAVs for assessment of bridge infrastructure

The shortcomings of classical methods for inspection of transport infrastructure objects have led to the development of more efficient, more reliable, faster and cheaper procedures for condition assessment and load-bearing capacity and service life estimation of objects. In this context, different autonomous systems developed in the last decade have the most notable role and their development is continuously speeding up. This paper provides a state of the art review of the unmanned aerial vehicles application for structural inspection with a focus on bridges. The paper comprises the following: a review of the current regulations prescribing the types and frequency of inspections; a review of the current classical inspection methods with their advantages and disadvantages; analysis of advantages and disadvantages in application of unmanned aerial vehicles for bridge inspections and a review of the equipment commonly used in their development.

INTERPRETATION OF HISTORIC STRUCTURE FOR NON-INVASIVE ASSESSMENT USING EYE TRACKING

With the aims of ensuring safety and decreasing maintenance costs, previous studies in bridge inspection research have worked to elucidate damage indicators and understand their correspondence to structural deficiency. During this process, understanding how an inspector looks at a structure comprehensively as well as how they localize on damage is vital to examining diagnostic bias and how it can play a role in the preservation and maintenance process. To understand human perception and assess the humaninfrastructure interaction during the feature extraction process, eye tracking can be useful. Eye tracking data can accurately map where a human is looking and what they are focusing on based on metrics such as fixation, saccade, pupil dilation, and scan path. The present research highlights the use of eye tracking metrics for recognizing and inferring human implicit attention and intention while performing a structural inspection. These metrics will be used to learn the behavior of human eyes and how detection tasks can change a person’s overall behavior. A preliminary study has been carried out for damage detection to analyze key features that are important for understanding human-infrastructure interaction during damage assessment. These eye tracking features will lay the foundation for human intent prediction and how an inspector performs inspection on historic structures for existing types of damage. In future, the results of this work will be used to train a machine learning agent for autonomous and reactive decision making.

An Insight into Chemistry and Structure of Colloidal 2D-WS2 Nanoflakes: Combined XPS and XRD Study

The surface and structural characterization techniques of three atom-thick bi-dimensional 2D-WS2 colloidal nanocrystals cross the limit of bulk investigation, offering the possibility of simultaneous phase identification, structural-to-morphological evaluation, and surface chemical description. In the present study, we report a rational understanding based on X-ray photoelectron spectroscopy (XPS) and structural inspection of two kinds of dimensionally controllable 2D-WS2 colloidal nanoflakes (NFLs) generated with a surfactant assisted non-hydrolytic route. The qualitative and quantitative determination of 1T’ and 2H phases based on W 4f XPS signal components, together with the presence of two kinds of sulfur ions, S22− and S2−, based on S 2p signal and related to the formation of WS2 and WOxSy in a mixed oxygen-sulfur environment, are carefully reported and discussed for both nanocrystals breeds. The XPS results are used as an input for detailed X-ray Diffraction (XRD) analysis allowing for a clear discrimination of NFLs crystal habit, and an estimation of the exact number of atomic monolayers composing the 2D-WS2 nanocrystalline samples.

Assessment of flight dynamic and static aeroelastic behaviors for jet transport aircraft subjected to instantaneous high g-loads

Purpose The purpose of this paper is to present a quick inspection method based on the post-flight data to examine static aeroelastic behavior for transport aircraft subjected to instantaneous high g-loads. Design/methodology/approach In the present study, the numerical approach of static aeroelasticity and two verified cases will be presented. The non-linear unsteady aerodynamic models are established through flight data mining and the fuzzy-logic modeling of artificial intelligence techniques based on post-flight data. The first and second derivatives of flight dynamic and static aeroelastic behaviors, respectively, are then estimated by using these aerodynamic models. Findings The flight dynamic and static aeroelastic behaviors with instantaneous high g-load for the two transports will be analyzed and make a comparison study. The circumstance of turbulence encounter of the new twin-jet is much serious than that of four-jet transport aircraft, but the characteristic of stability and controllability for the new twin-jet is better than those of the four-jet transport aircraft; the new twin-jet transport is also shown to have very small aeroelastic effects. The static aeroelastic behaviors for the two different types can be assessed by using this method. Practical implications As the present study uses the flight data stored in a quick access recorder, an intrusive structural inspection of the post-flight can be avoided. A tentative conclusion is to prove that this method can be adapted to examine the static aeroelastic effects for transport aircraft of different weights, different sizes and different service years in tracking static aeroelastic behavior of existing different types of aircraft. In future research, one can consider to have more issues of other types of aircraft with high composite structure weight. Originality/value This method can be used to assist airlines to monitor the variations of flight dynamic and static aeroelastic behaviors as a complementary tool for management to improve aviation safety, operation and operational efficiency.