Advanced numerical study of impact forces on railway sleepers under wheel flat

Wheel-rail interaction is one of the most important research topics in railway engineering. It includes track vibration, track impact response and safety of the track. Track structure failures caused by impact forces can lead to significant economic loss for track owners through damage to rails and to the sleepers beneath. The wheel-rail impact forces occur because of imperfections on the wheels or rails such as wheel flats, irregular wheel profile, rail corrugation and differences in the height of rails connected at a welded joint. In this paper, a finite element model for the wheel flat study is developed by use of the FEA software package ANSYS. The effect of the wheel flat to impact force on sleepers is investigated. It has found that the wheel flat significantly increases impact forces and maximum Von Mises stress, and also delays the peak position of dynamic variation for impact forces on both rail and sleeper.

The adoption of advanced quality practices and its impact on manufacturers

Presently, the manufacturing sector faces unprecedented levels of competition in both the domestic and international markets. This competition is mainly as a result of rapidly expanding international trade, gradual removal of protection, substantial reforms in labour markets and industrial relations, rapid technological changes and discerning customers. Intense global competition requires manufacturers to deliver products with higher quality in a shorter time. Simultaneously, owing to new technological innovations, the complexity of the products is increasing. In Australia, the impact of this intense competition and structural changes appear to be having negative effects on the manufacturing sector. This paper discusses the quality and reliability (Q & R) practices and associated drawbacks of Australian manufacturers and presents the findings of an investigation of the challenges Australian manufacturers are currently facing. The results reported in the paper are based on the data collected from a survey using the standard questionnaire. The study was driven by a conceptual model, which relates advanced quality practices to manufacturing performance and manufacturing difficulties.Evidence indicates that Q & R is the main competitive factor for Australian manufacturers. Design capability and on time delivery (OTD) came second. Results show that Australian manufacturers in general are facing some manufacturing difficulties. The relationship between advanced quality practices and company performance and manufacturing difficulties are explored. It is found that the companies who have more emphasis on advanced quality practices have fewer problems in manufacturing practices. Moreover, companies who have actively implemented the advanced quality practices have managed to improve the quality of the product continuously. The results validate the proposed hypothesis and lend credence to current thinking that improvement in Q & R is a vital tool for competitive advantage.

Advanced numerical characterization of mono-crystalline copper with defects

Based on the embedded atom method (EAM) and molecular dynamics (MD) method, the mono-crystalline copper with different defects is investigated through tension and nanoindentation simulation. The single-crystal copper nanowire with surface defects is firstly studied through tension. For validation, the tension simulations for nanowire without defect are carried out under different temperatures and strain rates. The defects on nanowires are then systematically studied in considering different defects orientation distribution. It is found that the Young’s modulus is insensitive of surface defects and centro-plane defects. However, the yield strength and yield point show a significant decrease due to the different defects. Specially, the 〖45〗^° defect in surface and in (200) plane exerts the biggest influence to the yield strength, about 34.20% and 51.45% decrease are observed, respectively. Different defects are observed to serve as a dislocation source and different necking positions of the nanowires during tension are found. During nanoindentation simulation, dislocation is found nucleating below the contact area, but no obvious dislocation is generated around the nano-cavity. Comparing with the perfect substrate during nanoindentation, the substrate with nano-cavities emerged less dislocations, it is supposed that the nano-cavity absorbed part of the indent energy, and less plastic deformation happened in the defected substrate.

Diels-Alder reactions as an efficient route to high purity cyclic polymers

A simple and efficient route for the synthesis of cyclic polymer systems is presented. Linear furan protected α-maleimide-ω-cyclopentadienyl functionalized precursors (poly(methyl methacrylate) and poly(tert-butyl acrylate)) were synthesized via atom transfer radical polymerization (ATRP) and subsequent substitution of the bromine end-group with cyclopentadiene. Upon heating at high dilution, deprotection of the dieneophile occurs followed by an intramolecular Diels–Alder reaction yielding a high purity cyclic product.

Photoinduced conjugation of Dithioester- and Trithiocarbonate-Functional RAFT polymers with alkenes

We report the photoinduced conjugation of polymers synthesized via reversible addition−fragmentation chain transfer (RAFT) polymerization with a number of low molecular weight (functional) olefins. Upon irradiation of a solution of an aliphatic alkene and the benzyl dithioacetic acid ester (CPDA) or dodecyl trithiocarbonate (DoPAT) functional poly(alkyl acrylate) at the absorption wavelength of the thiocarbonyl group (315 nm), incorporation of the alkene at the polymer chain-end occurred. The most efficient systems identified with regard to the rate of reaction and yield were poly(butyl acrylate)/CPDA/ethyl vinyl ether (78% monoinsertion product after 1 h) and poly(butyl acrylate)/CPDA/1-pentene (73% insertion product after 7 h) at ambient temperature. An in-depth analysis of the reaction mechanism by 1H NMR and online size-exclusion chromatography-electrospray ionization tandem mass spectrometry (SEC/ESI−MSn) revealed that a possible [2 + 2] photoaddition mechanism of conjugation does not take place. Instead, fast β-cleavage of the photoexcited RAFT-end group with subsequent radical addition of an alkene was observed for all employed systems. The presented reaction thus provides a means of spatial and temporal control for the conjugation of alkenes to thiocarbonyl thio-capped macromolecules via the use of UV radiation.

Chain scission resists for extreme ultraviolet lithography based on high performance polysulfone-containing polymers

A series of polymers with a comb architecture were prepared where the poly(olefin sulfone) backbone was designed to be highly sensitive to extreme ultraviolet (EUV) radiation, while the well-defined poly(methyl methacrylate) (PMMA) arms were incorporated with the aim of increasing structural stability. It is hypothesized that upon EUV radiation rapid degradation of the polysulfone backbone will occur leaving behind the well-defined PMMA arms. The synthesized polymers were characterised and have had their performance as chain-scission EUV photoresists evaluated. It was found that all materials possess high sensitivity towards degradation by EUV radiation (E0 in the range 4–6 mJ cm−2). Selective degradation of the poly(1-pentene sulfone) backbone relative to the PMMA arms was demonstrated by mass spectrometry headspace analysis during EUV irradiation and by grazing-angle ATR-FTIR. EUV interference patterning has shown that materials are capable of resolving 30 nm 1:1 line:space features. The incorporation of PMMA was found to increase the structural integrity of the patterned features. Thus, it has been shown that terpolymer materials possessing a highly sensitive poly(olefin sulfone) backbone and PMMA arms are able to provide a tuneable materials platform for chain scission EUV resists. These materials have the potential to benefit applications that require nanopattering, such as computer chip manufacture and nano-MEMS.

The aetiology, impact and management of cancer-related fatigue in patients with advanced cancer

Cancer-related fatigue (CRF) is a distressing symptom frequently experienced by patients with advanced cancer. While there have been some advances in the understanding of the management of fatigue associated with cancer treatment, CRF associated with advanced cancer remains a phenomenon that is not well-managed. The aetiologic factors associated with CRF, the impacts of CRF and the current management of CRF are discussed in this review article in relation to patients with advanced cancer. The paper concludes that while further research is required in the area, there are several potentially effective strategies currently available that can reduce the severity of CRF in patients with advanced cancer.

Advanced Computational Intelligence System for inverse aeronautical design optimisation

Abstract—Computational Intelligence Systems (CIS) is one of advanced softwares. CIS has been important position for solving single-objective / reverse / inverse and multi-objective design problems in engineering. The paper hybridise a CIS for optimisation with the concept of Nash-Equilibrium as an optimisation pre-conditioner to accelerate the optimisation process. The hybridised CIS (Hybrid Intelligence System) coupled to the Finite Element Analysis (FEA) tool and one type of Computer Aided Design(CAD) system; GiD is applied to solve an inverse engineering design problem; reconstruction of High Lift Systems (HLS). Numerical results obtained by the hybridised CIS are compared to the results obtained by the original CIS. The benefits of using the concept of Nash-Equilibrium are clearly demonstrated in terms of solution accuracy and optimisation efficiency.

Toward automated power line corridor monitoring using advanced aircraft control and multisource feature fusion

The conventional manual power line corridor inspection processes that are used by most energy utilities are labor-intensive, time consuming and expensive. Remote sensing technologies represent an attractive and cost-effective alternative approach to these monitoring activities. This paper presents a comprehensive investigation into automated remote sensing based power line corridor monitoring, focusing on recent innovations in the area of increased automation of fixed-wing platforms for aerial data collection, and automated data processing for object recognition using a feature fusion process. Airborne automation is achieved by using a novel approach that provides improved lateral control for tracking corridors and automatic real-time dynamic turning for flying between corridor segments, we call this approach PTAGS. Improved object recognition is achieved by fusing information from multi-sensor (LiDAR and imagery) data and multiple visual feature descriptors (color and texture). The results from our experiments and field survey illustrate the effectiveness of the proposed aircraft control and feature fusion approaches.