Health State Prediction of Aero-Engine Gas Path System Considering Multiple Working Conditions Based on Time Domain Analysis and Belief Rule Base

The gas path system is an important part of an aero-engine, whose health states can affect the security of the airplane. During the process of aircraft operation, the gas path system will have different working conditions over time, owing to the change of control parameters. However, the different working conditions which change the symmetry of the system will affect parameters of the health state prediction model for the gas path system. The symmetry of the system will also change. Therefore, it is important to consider the influence of variable working conditions when predicting the health states of gas path system. The accuracy of the health state prediction results of the gas path system will be low if the same evaluation standard is used for different working conditions. In addition, the monitoring data of the gas path system’s health state feature quantity is huge while the fault data which can reflect the health states of the gas path system are poor. Thus, it is difficult to establish a health state prediction model only by using the monitoring data of the gas path system. In order to avoid problems, this paper proposes a health state prediction model considering multiple working conditions based on time domain analysis and a belief rule base. First, working condition is divided by using time domain characteristics. Then, a belief rule base (BRB) theory-based health state prediction model is built, which can fuse expert knowledge and fault monitoring data to improve modeling accuracy. The reference value of the feature is given by the fuzzy C-means algorithm in a model. To decrease the uncertainty of expert knowledge, the covariance matrix adaptive evolution strategy (CMA-ES) is used as the optimization algorithm. Finally, a NASA public dataset without labels is used to verify the proposed health state model. The results show that the proposed health prediction model of a gas path system can accurately realize health state prediction under multiple working conditions.

High-quality quasi-parallel X-ray beam obtained by a parabolic monocapillary X-ray lens with a square beam stop

Parabolic monocapillary X-ray lens (PMXRL) is an ideal optical device for constraining the point divergent X-ray beams to quasi-parallel beams, but the overlap of direct X-rays and reflected X-rays through PMXRL deteriorates the outgoing beam divergence. Aiming to solve this problem, this study designs and tests a square-shaped lead occluder (SSLO) embedded in PMXRL to block the direct X-rays passing through the PMXRL. Python simulations are employed to determine the geometric parameters of the SSLO as well as the optimal position of the SSLO in the PMXRL according to our proposed model. The PMXRL with a conic parameter p of 0.000939 mm and a length L of 60.8 mm is manufactured and the SSLO with a size of 0.472 mm×0.472 mm×3.4 mm is embedded into it. An optical path system based on this PMXRL is built to measure the divergence of the outgoing X-ray beam. The experimental results show that the quasi-parallel X-ray beam reaches a divergence of 0.36 mrad in the range from 15–45 mm at the PMXRL outlet. This divergence is 10 times lower than the theoretical divergence without SSLO. Our work provides an alternative method for obtaining highly parallel X-ray beam and is beneficial to generate or facilitate new applications of monocapillary optics in X-ray technology.

Dependable Sensor Fault Reconstruction in Air-Path System of Heavy-Duty Diesel Engines

This paper addresses the problem of robust sensor faults detection and isolation in the air-path system of heavy-duty diesel engines, which has not been completely considered in the literature. Calibration or the total failure of a sensor can cause sensor faults. In the worst-case scenario, the engines can be totally damaged by the sensor faults. For this purpose, a second-order sliding mode observer is proposed to reconstruct the sensor faults in the presence of unknown external disturbances. To this aim, the concept of the equivalent output error injection method and the linear matrix inequality (LMI) tool are utilized to minimize the effects of uncertainties and disturbances on the reconstructed fault signals. The simulation results verify the performance and robustness of the proposed method. By reconstructing the sensor faults, the whole system can be prevented from failing before the corrupted sensor measurements are used by the controller.

Experience-driven heritage

<p>Within the Wellington region, there are a number of abandoned military fortifications which were designed as a coastal defence system to protect the harbour from Russian attacks in late 19th Century. Changing circumstances have meant that this coastal defence infrastructure network is no longer functional, and this research aims to bring it back to life. The site chosen for this research investigation is Watts Peninsula, which is enjoyed by only a limited number of the wider public who only visit a small part of the site. The great size and topography of the landscape makes it a serious challenge to manage let alone transform. This site therefore seems to be a great opportunity to explore the disciplinary challenge of how to bring coastal military fortification sites back to life? Traditionally, the way to bring coastal sites with abandoned fortifications back to life is by treating them as heritage projects. They are protected and sometimes developed as more or less significant tourist destinations that display the significance of military history and heritage. This approach tends to break up the landscape into key areas, with the minimal path system required to connect up the various heritage items and locations on the site. This typical approach severely limits the range and richness of experiencing potential of a site like Watts Peninsula. This thesis will approach this project by engaging with the countless experiences found within the existing landscape; stepping the normal heritage approach. Topography, slope, vegetation cover, aspect and views were found to produce a great range of effectively separately experienced patches or landscape-experience zones. This thesis sought to understand how the site produced the involuntary types of movement-experiencing that it did and how it differentiated itself into these experience-zones. The types of experiencing that the site produced seemed to have a great deal to do with the interaction of paths/movement through the various mosaic of experience-zones. The aim of the analysis was to discover the actual and potential ways that the site is differentiated into these experience-areas and the actual and potential movement experiences that could allow access to these areas. The design investigation would aim to maximise the number and variety of these movement and experience-zones. The resulting development would aim to spread a complex mosaic-network of experiencing across as much of the site as possible. This network would be intended to develop in a way where the great richness of possible experiences and the mystery of the site are both increased. The project would require significant funds and so a housing scheme on the southern edge of the site seemed the most obvious way to provide income for such a development. The intended housing development was designed to increase the local population who would have access to the site but hopefully in a manner where the housing would not seriously impact on views to, or the experiences and mystery of the site. Overall, the design development would be intended to transform this landscape into a destination for varieties of adventuring, exploring and experiencing on a remarkable landscape. With the help of the housing, the possibility of this being an urban adventuring destination and the network of paths and experiencing could then provide something of a way to make the heritage transformation of the fortifications themselves a viable prospect. The treatment of the fortifications has not been engaged with in this project. So, it can be said that this research has attempted to avoid the normal way that coastal military fortifications tend to be developed and proposed, instead, an experience-driven approach to the site and to heritage.</p>

Experience-driven heritage

<p>Within the Wellington region, there are a number of abandoned military fortifications which were designed as a coastal defence system to protect the harbour from Russian attacks in late 19th Century. Changing circumstances have meant that this coastal defence infrastructure network is no longer functional, and this research aims to bring it back to life. The site chosen for this research investigation is Watts Peninsula, which is enjoyed by only a limited number of the wider public who only visit a small part of the site. The great size and topography of the landscape makes it a serious challenge to manage let alone transform. This site therefore seems to be a great opportunity to explore the disciplinary challenge of how to bring coastal military fortification sites back to life? Traditionally, the way to bring coastal sites with abandoned fortifications back to life is by treating them as heritage projects. They are protected and sometimes developed as more or less significant tourist destinations that display the significance of military history and heritage. This approach tends to break up the landscape into key areas, with the minimal path system required to connect up the various heritage items and locations on the site. This typical approach severely limits the range and richness of experiencing potential of a site like Watts Peninsula. This thesis will approach this project by engaging with the countless experiences found within the existing landscape; stepping the normal heritage approach. Topography, slope, vegetation cover, aspect and views were found to produce a great range of effectively separately experienced patches or landscape-experience zones. This thesis sought to understand how the site produced the involuntary types of movement-experiencing that it did and how it differentiated itself into these experience-zones. The types of experiencing that the site produced seemed to have a great deal to do with the interaction of paths/movement through the various mosaic of experience-zones. The aim of the analysis was to discover the actual and potential ways that the site is differentiated into these experience-areas and the actual and potential movement experiences that could allow access to these areas. The design investigation would aim to maximise the number and variety of these movement and experience-zones. The resulting development would aim to spread a complex mosaic-network of experiencing across as much of the site as possible. This network would be intended to develop in a way where the great richness of possible experiences and the mystery of the site are both increased. The project would require significant funds and so a housing scheme on the southern edge of the site seemed the most obvious way to provide income for such a development. The intended housing development was designed to increase the local population who would have access to the site but hopefully in a manner where the housing would not seriously impact on views to, or the experiences and mystery of the site. Overall, the design development would be intended to transform this landscape into a destination for varieties of adventuring, exploring and experiencing on a remarkable landscape. With the help of the housing, the possibility of this being an urban adventuring destination and the network of paths and experiencing could then provide something of a way to make the heritage transformation of the fortifications themselves a viable prospect. The treatment of the fortifications has not been engaged with in this project. So, it can be said that this research has attempted to avoid the normal way that coastal military fortifications tend to be developed and proposed, instead, an experience-driven approach to the site and to heritage.</p>

Physical Modeling of Semi-continuous Casting for Developing an Industrial Technology of Producing Ingots From New Deformable Aluminum Alloys

A physical model of a semi-continuous casting unit (SCCU) has been manufactured and tested, designed to develop a technology for casting flat and cylindrical ingots from experimental aluminum alloys for subsequent metal forming. The SCCU includes two induction melting furnaces with a tilting mechanism, a rotary mixer, a metal path system, a vertical casting machine, a jib crane, water supply, power supply, monitoring and control systems. SCCU testing was carried out on six heats of alloy 1580 of the Al-Mg system with the addition of scandium. In the first three ingots the scandium content was 0.05% (wt.). In the second series of three heats ingots with 0.075% (wt.) scandium were cast. The ingots had a high surface quality, did not have casting defects, and there were no inclusions of primary intermetallic compounds Al3(Sc, Zr) in the structure of the ingots. The bottom and runner parts of the ingots were cut off, all faces were milled and subjected to homogenization annealing in a two-stage mode: the first heating at 350 °C, 3 h, the second heating for 1 h to 425 °C, 4 h. Then the billets were hot rolled from 40 to 5 mm, annealed at 380 °C, 1 h, rolled at room temperature to a thickness of 1 mm and annealed at 350 °C, 3 h. After that, tensile mechanical properties were tested. The results of modeling ingot casting were tested in industrial conditions when casting a large ingot with a cross section of 2100×500 mm. A template was cut from the ingot with the dimensions of a billet for rolling, as that obtained from an experimental ingot cast at the SCCU. The billet was subjected to hot and cold rolling according to the conditions used for rolling the experimental ingot. At the same time the modes of heat treatment of sheet semi-finished products were also repeated. The mechanical properties of sheets of alloy 1580 rolled from experimental and industrial ingots practically did not differ. This proves the reliability of casting modes for ingots obtained at the SCCU and tested for casting industrial ingots.

Asynchronous Teleconsultations: The US Military Experience in the Pacific

Tripler Army Medical Center (TAMC), located in Honolulu, Hawaii, serves as the US military’s tertiary medical referral center for the Western Pacific. Over 20 years ago, the TAMC Department of Pediatrics developed an asynchronous provider-to-provider teleconsultation pilot program, eventually named the Pacific Asynchronous TeleHealth (PATH) system. A secure teleconsultation platform for pediatric sub-specialty provider-to-provider advice, the platform grew based on the needs of users, eventually expanding to serve all age-groups, with over 60 different specialties based at TAMC providing teleconsultation. Eventually, the success of PATH drove further expansion to serve military clinicians located in other overseas locations beyond the Asia-Pacific. This cost-effective model can be applied to civilian healthcare settings, particularly where geographic distance or limited connectivity are challenges to delivery of synchronous telehealth or in-person specialty care.