Ultimate flexural limit states analysis of prestressed concrete sleeper

Railway is one of the most important, reliable and widely used means of transportation, carrying freight, passengers, minerals, grains, etc. Thus, research on railway tracks is extremely important for the development of railway engineering and technologies. The safe operation of a railway track is based on the railway track structure that includes rails, fasteners, pads, sleepers, ballast, subballast and formation. Sleepers are very important components of the entire structure and may be made of timber, concrete, steel or synthetic materials. Concrete sleepers were first installed around the middle of last century and currently are installed in great numbers around the world. Consequently, the design of concrete sleepers has a direct impact on the safe operation of railways. The "permissible stress" method is currently most commonly used to design sleepers. However, the permissible stress principle does not consider the ultimate strength of materials, probabilities of actual loads, and the risks associated with failure, all of which could lead to the conclusion of cost-ineffectiveness and over design of current prestressed concrete sleepers. Recently the limit states design method, which appeared in the last century and has been already applied in the design of buildings, bridges, etc, is proposed as a better method for the design of prestressed concrete sleepers. The limit states design has significant advantages compared to the permissible stress design, such as the utilisation of the full strength of the member, and a rational analysis of the probabilities related to sleeper strength and applied loads. This research aims to apply the ultimate limit states design to the prestressed concrete sleeper, namely to obtain the load factors of both static and dynamic loads for the ultimate limit states design equations. However, the sleepers in rail tracks require different safety levels for different types of tracks, which mean the different types of tracks have different load factors of limit states design equations. Therefore, the core tasks of this research are to find the load factors of the static component and dynamic component of loads on track and the strength reduction factor of the sleeper bending strength for the ultimate limit states design equations for four main types of tracks, i.e., heavy haul, freight, medium speed passenger and high speed passenger tracks. To find those factors, the multiple samples of static loads, dynamic loads and their distributions are needed. In the four types of tracks, the heavy haul track has the measured data from Braeside Line (A heavy haul line in Central Queensland), and the distributions of both static and dynamic loads can be found from these data. The other three types of tracks have no measured data from sites and the experimental data are hardly available. In order to generate the data samples and obtain their distributions, the computer based simulations were employed and assumed the wheel-track impacts as induced by different sizes of wheel flats. A valid simulation package named DTrack was firstly employed to generate the dynamic loads for the freight and medium speed passenger tracks. However, DTrack is only valid for the tracks which carry low or medium speed vehicles. Therefore, a 3-D finite element (FE) model was then established for the wheel-track impact analysis of the high speed track. This FE model has been validated by comparing its simulation results with the DTrack simulation results, and with the results from traditional theoretical calculations based on the case of heavy haul track. Furthermore, the dynamic load data of the high speed track were obtained from the FE model and the distributions of both static and dynamic loads were extracted accordingly. All derived distributions of loads were fitted by appropriate functions. Through extrapolating those distributions, the important parameters of distributions for the static load induced sleeper bending moment and the extreme wheel-rail impact force induced sleeper dynamic bending moments and finally, the load factors, were obtained. Eventually, the load factors were obtained by the limit states design calibration based on reliability analyses with the derived distributions. After that, a sensitivity analysis was performed and the reliability of the achieved limit states design equations was confirmed. It has been found that the limit states design can be effectively applied to railway concrete sleepers. This research significantly contributes to railway engineering and the track safety area. It helps to decrease the failure and risks of track structure and accidents; better determines the load range for existing sleepers in track; better rates the strength of concrete sleepers to support bigger impact and loads on railway track; increases the reliability of the concrete sleepers and hugely saves investments on railway industries. Based on this research, many other bodies of research can be promoted in the future. Firstly, it has been found that the 3-D FE model is suitable for the study of track loadings and track structure vibrations. Secondly, the equations for serviceability and damageability limit states can be developed based on the concepts of limit states design equations of concrete sleepers obtained in this research, which are for the ultimate limit states.

Visualising experimental flow fields through a stormwater gross pollutant trap

Abstract An experimental dataset representing a typical flow field in a stormwater gross pollutant trap (GPT) was visualised. A technique was developed to apply the image-based flow visualisation (IBFV) algorithm to the raw dataset. Particle image velocimetry (PIV) software was previously used to capture the flow field data by tracking neutrally buoyant particles with a high speed camera. The dataset consisted of scattered 2D point velocity vectors and the IBFV visualisation facilitates flow feature characterisation within the GPT. The flow features played a pivotal role in understanding stormwater pollutant capture and retention behaviour within the GPT. It was found that the IBFV animations revealed otherwise unnoticed flow features and experimental artefacts. For example, a circular tracer marker in the IBFV program visually highlighted streamlines to investigate the possible flow paths of pollutants entering the GPT. The investigated flow paths were compared with the behaviour of pollutants monitored during experiments.

Impact of extracellular matrix derived from osteoarthritis subchondral bone osteoblasts on osteocytes : role of integrinβ1 and focal adhesion kinase signaling cues

INTRODUCTION: Our recent study indicated that subchondral bone pathogenesis in osteoarthritis (OA) is associated with osteocyte morphology and phenotypic abnormalities. However, the mechanism underlying this abnormality needs to be identified. In this study we investigated the effect of extracellular matrix (ECM) produced from normal and OA bone on osteocytic cells function. METHODS: De-cellularized matrices, resembling the bone provisional ECM secreted from primary human subchondral bone osteoblasts (SBOs) of normal and OA patients were used as a model to study the effect on osteocytic cells. Osteocytic cells (MLOY4 osteocyte cell line) cultured on normal and OA derived ECMs were analyzed by confocal microscopy, scanning electron microscopy (SEM), cell attachment assays, zymography, apoptosis assays, qRT-PCR and western blotting. The role of integrinβ1 and focal adhesion kinase (FAK) signaling pathways during these interactions were monitored using appropriate blocking antibodies. RESULTS: The ECM produced by OA SBOs contained less mineral content, showed altered organization of matrix proteins and matrix structure compared with the matrices produced by normal SBOs. Culture of osteocytic cells on these defective OA ECM resulted in a decrease of integrinβ1 expression and the de-activation of FAK cell signaling pathway, which subsequently affected the initial osteocytic cell's attachment and functions including morphological abnormalities of cytoskeletal structures, focal adhesions, increased apoptosis, altered osteocyte specific gene expression and increased Matrix metalloproteinases (MMP-2) and -9 expression. CONCLUSION: This study provides new insights in understanding how altered OA bone matrix can lead to the abnormal osteocyte phenotypic changes, which is typical in OA pathogenesis.

Spectroscopic correlation analysis of NMR-based metabonomics in exercise science

Spectroscopic studies of complex clinical fluids have led to the application of a more holistic approach to their chemical analysis becoming more popular and widely employed. The efficient and effective interpretation of multidimensional spectroscopic data relies on many chemometric techniques and one such group of tools is represented by so-called correlation analysis methods. Typical of these techniques are two-dimensional correlation analysis and statistical total correlation spectroscopy (STOCSY). Whilst the former has largely been applied to optical spectroscopic analysis, STOCSY was developed and has been applied almost exclusively to NMR metabonomic studies. Using a 1H NMR study of human blood plasma, from subjects recovering from exhaustive exercise trials, the basic concepts and applications of these techniques are examined. Typical information from their application to NMR-based metabonomics is presented and their value in aiding interpretation of NMR data obtained from biological systems is illustrated. Major energy metabolites are identified in the NMR spectra and the dynamics of their appearance and removal from plasma during exercise recovery are illustrated and discussed. The complementary nature of two-dimensional correlation analysis and statistical total correlation spectroscopy are highlighted.

A Raman spectroscopic comparison of calcite and dolomite

Raman spectroscopy was used to characterize and differentiate the two minerals calcite and dolomite and the bands related to the mineral structure. The (CO3)2− group is characterized by four prominent Raman vibrational modes: (a) the symmetric stretching, (b) the asymmetric deformation, (c) asymmetric stretching and (d) symmetric deformation. These vibrational modes of the calcite and dolomite were observed at 1440, 1088, 715 and 278 cm−1. The significant differences between the minerals calcite and dolomite are observed by Raman spectroscopy. Calcite shows the typical bands observed at 1361, 1047, 715 and 157 cm−1, and the special bands at 1393, 1098, 1069, 1019, 299, 258 and 176 cm−1 for dolomite are observed. The difference is explained on the basis of the structure variation of the two minerals. Calcite has a trigonal structure with two molecules per unit cell, and dolomite has a hexagonal structure. This is more likely to cause the splitting and distorting of the carbonate groups. Another cause for the difference is the cation substituting for Mg in the dolomite mineral.

Living the indie life : mapping creative teams in a 48 hour game jam and playing with data

In contemporary game development circles the ‘game making jam’ has become an important rite of passage and baptism event, an exploration space and a central indie lifestyle affirmation and community event. Game jams have recently become a focus for design researchers interested in the creative process. In this paper we tell the story of an established local game jam and our various documentation and data collection methods. We present the beginnings of the current project, which seeks to map the creative teams and their process in the space of the challenge, and which aims to enable participants to be more than the objects of the data collection. A perceived issue is that typical documentation approaches are ‘about’ the event as opposed to ‘made by’ the participants and are thus both at odds with the spirit of the jam as a phenomenon and do not really access the rich playful potential of participant experience. In the data collection and visualisation projects described here, we focus on using collected data to re-include the participants in telling stories about their experiences of the event as a place-based experience. Our goal is to find a means to encourage production of ‘anecdata’ - data based on individual story telling that is subjective, malleable, and resists collection via formal mechanisms - and to enable mimesis, or active narrating, on the part of the participants. We present a concept design for data as game based on the logic of early medieval maps and we reflect on how we could enable participation in the data collection itself.

2 Hour game jam at SLQ Garage Gamer - Live performance with crowd participation

The 2 hour game jam was performed as part of the State Library of Queensland 'Garage Gamer' series of events, summer 2013, at the SLQ exhibition. An aspect of the exhibition was the series of 'Level Up' game nights. We hosted the first of these - under the auspices of brIGDA, Game On. It was a party - but the focal point of the event was a live streamed 2 hour game jam. Game jams have become popular amongst the game development and design community in recent years, particularly with the growth of the Global Game Jam, a yearly event which brings thousands of game makers together across different sites in different countries. Other established jams take place on-line, for example the Ludum Dare challenge which as been running since 2002. Other challenges follow the same model in more intimate circumstances and it is now common to find institutions and groups holding their own small local game making jams. There are variations around the format, some jams are more competitive than others for example, but a common aspect is the creation of an intense creative crucible centred around team work and ‘accelerated game development’. Works (games) produced during these intense events often display more experimental qualities than those undertaken as commercial projects. In part this is because the typical jam is started with a conceptual design brief, perhaps a single word, or in the case of the specific game jam described in this paper, three words. Teams have to envision the challenge key word/s as a game design using whatever skills and technologies they can and produce a finished working game in the time given. Game jams thus provide design researchers with extraordinary fodder and recent years have also seen a number of projects which seek to illuminate the design process as seen in these events. For example, Gaydos, Harris and Martinez discuss the opportunity of the jam to expose students to principles of design process and design spaces (2011). Rouse muses on the game jam ‘as radical practice’ and a ‘corrective to game creation as it is normally practiced’. His observations about his own experience in a jam emphasise the same artistic endeavour forefronted earlier, where the experience is about creation that is divorced from the instrumental motivations of commercial game design (Rouse 2011) and where the focus is on process over product. Other participants remark on the social milieu of the event as a critical factor and the collaborative opportunity as a rich site to engage participants in design processes (Shin et al, 2012). Shin et al are particularly interested in the notion of the site of the process and the ramifications of participants being in the same location. They applaud the more localized event where there is an emphasis on local participation and collaboration. For other commentators, it is specifically the social experience in the place of the jam is the most important aspect (See Keogh 2011), not the material site but rather the physical embodied experience of ‘being there’ and being part of the event. Participants talk about game jams they have attended in a similar manner to those observations made by Dourish where the experience is layered on top of the physical space of the event (Dourish 2006). It is as if the event has taken on qualities of place where we find echoes of Tuan’s description of a particular site having an aura of history that makes it a very different place, redolent and evocative (Tuan 1977). The 2 hour game jam held during the SLQ Garage Gamer program was all about social experience.

Formalising human recognition : a fundamental building block for security proofs

A fundamental part of many authentication protocols which authenticate a party to a human involves the human recognizing or otherwise processing a message received from the party. Examples include typical implementations of Verified by Visa in which a message, previously stored by the human at a bank, is sent by the bank to the human to authenticate the bank to the human; or the expectation that humans will recognize or verify an extended validation certificate in a HTTPS context. This paper presents general definitions and building blocks for the modelling and analysis of human recognition in authentication protocols, allowing the creation of proofs for protocols which include humans. We cover both generalized trawling and human-specific targeted attacks. As examples of the range of uses of our construction, we use the model presented in this paper to prove the security of a mutual authentication login protocol and a human-assisted device pairing protocol.

A novel iterative method for simulating patient-specific optimal deformation and fit of fracture fixation plates

This paper proposes a new iterative method to achieve an optimally fitting plate for preoperative planning purposes. The proposed method involves integration of four commercially available software tools, Matlab, Rapidform2006, SolidWorks and ANSYS, each performing specific tasks to obtain a plate shape that fits optimally for an individual tibia and is mechanically safe. A typical challenge when crossing multiple platforms is to ensure correct data transfer. We present an example of the implementation of the proposed method to demonstrate successful data transfer between the four platforms and the feasibility of the method.

Risk compensation in construction workers' activities

Construction has been plagued with serious injuries and deaths for years. Although the technological advances have made the world safer and healthier, researchers have noted that some safety interventions, which had clear objective safety benefits, had failed to achieve the forecast savings in lives and injuries. The purpose of this study was to explore whether the construction workers show risk compensation and engage in greater risk taking when certain types of safety measures are implemented in the construction site. A case study approach was used to achieve the aim of this study. A typical construction site in Sydney was selected as the subject of the case study. Data were collected through direct observations, questionnaires and interviews. The findings confirm that workers show risk compensation behaviours in the construction environment. The risk compensation behaviours of workers varied with the level of experience and whether they have suffered from a past workplace injury. The findings of this study may offer a better understanding of workers’ behavioural patterns in construction environment and the effectiveness of safety interventions. The result of this study may provide supports for designing, implementing and evaluating safety interventions in construction site.

The inaccuracy of national character stereotypes

Consensual stereotypes of some groups are relatively accurate, whereas others are not. Previous work suggesting that national character stereotypes are inaccurate has been criticized on several grounds. In this article we (a) provide arguments for the validity of assessed national mean trait levels as criteria for evaluating stereotype accuracy and (b) report new data on national character in 26 cultures from descriptions (N= 3323) of the typical male or female adolescent, adult, or old person in each. The average ratings were internally consistent and converged with independent stereotypes of the typical culture member, but were weakly related to objective assessments of personality. We argue that this conclusion is consistent with the broader literature on the inaccuracy of national character stereotypes

Does sustainable housing construction provide the home owner with a greater investment return?

Over the past 20 years there has been a considerable push at all three tiers of Government and private industry in Australia to improve the energy efficiency and sustainability levels of residential housing. A number of these initiatives have been voluntary, such as solar power and solar heating rebates, with other mandatory measures being incorporated into building standards and codes. Although the importance of energy efficiency and sustainable materials have been widely conveyed both at the academic and public level, it does not always reflect in the residential house purchase decision by typical house buyers, including residential property investors. This paper will analyse a range of housing markets in Brisbane to determine the investment performance of those markets over the past 3 years to determine any significant differences between new residential suburbs and older residential suburbs where houses have not been constructed to the current energy efficiency and sustainability guidelines. The range of suburbs to be analysed will focus on middle to lower high value suburbs, with a particular focus on residential housing in Master Planned Communities to determine if socio-economic factors and development size and scope have an impact of the purchase and investment performance of sustainable houses in comparison to older housing stock. The paper confirms that the residential property market shows a higher capital return for residential property built under stricter sustainability guidelines than similar located and type of property built prior to the BCA 2004 and older style project type homes erected prior to 2000.

Stereotypes of age differences in personality traits : universal and accurate?

Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups.

Inferring diffusion in single live cells at the single-molecule level

The movement of molecules inside living cells is a fundamental feature of biological processes. The ability to both observe and analyse the details of molecular diffusion in vivo at the single-molecule and single-cell level can add significant insight into understanding molecular architectures of diffus- ing molecules and the nanoscale environment in which the molecules diffuse. The tool of choice for monitoring dynamic molecular localization in live cells is fluorescence microscopy, especially so combining total internal reflection fluorescence with the use of fluorescent protein (FP) reporters in offering exceptional imaging contrast for dynamic processes in the cell mem- brane under relatively physiological conditions compared with competing single-molecule techniques. There exist several different complex modes of diffusion, and discriminating these from each other is challenging at the mol- ecular level owing to underlying stochastic behaviour. Analysis is traditionally performed using mean square displacements of tracked particles; however, this generally requires more data points than is typical for single FP tracks owing to photophysical instability. Presented here is a novel approach allowing robust Bayesian ranking of diffusion processes to dis-criminate multiple complex modes probabilistically. It is a computational approach that biologists can use to understand single-molecule features in live cells.

Pathogenicity of three RPV isolates of Barley Yellow Dwarf Virus on barley, wheat and wheat alien addition lines

Barleys with and without the Yd2 resistance factor, wheat alien addition stocks with other barley yellow dwarf virus (BYDV) resistance factors and true wheats were challenged with three Australian isolates of BYDV-RPV. Yd2 resistance was effective against two of the BYDV-RPV isolates and inoculated barleys which carry Yd2 did not develop BYD symptoms and shoot growth was not affected. However, barleys with Yd2 were susceptible to the third BYDV-RPV isolate. All barley lines inoculated with the third virus isolate developed typical BYD symptoms (yellowing), shoot growth was reduced compared to uninfected controls and virus titres determined by ELISA were high and similar in barleys with and without Yd2. In contrast, resistances from Thinopyrum intermedium and Agropyron pulcherrimum in wheat backgrounds were effective against all three BYDV-RPV isolates. Shoot growth of inoculated plants with either of these resistance factors did not differ from uninfected controls and virus titres determined by ELISA were very low.