Composing maternal identities : the living realities of mothers with young adult-children in twenty-first century Australia

There is an abundance of books available on the topic of motherhood and mothering; the majority of these books focus on the vulnerability of babies and young children and the motherwork such vulnerability demands. In particular they focus on what it is right to do in the interests of the child, and particularly his or her growth and development. Such a focus is consistent in Western culture with modern moral frameworks where understandings of goodness have been assimilated to dimensions of human action rather than dimensions of human being, selfhood, or specific forms of life. As Charles Taylor has observed, much modern moral philosophy has focused =on what it is right to do rather than the nature of the good life‘ (1989, 13). The master narratives of motherhood and the prevailing social discourses of intensive1 and sacrificial2 mothering exemplify this view as such narratives and discourses depict =what mothers are expected to do [and] how mothers are supposed to be‘ (Nelson 2001, 140). From such infant/child-focused accounts a canonical maternal identity can be discerned; arguably, it is a restricted one. The majority of these books fail to address questions related to what it means be a mother in particular situated, existing, living realities. For instance, ask a mother with young children what being a mother means to her and she may speak of the challenges she faces balancing paid employment and her role as a mother, or the impact of the demands being made on her time and energy. However, ask a mother with young adult-children3 what being a mother means to her and she may speak in similar tones, but she may also speak in differing tones. For example, a "mature" mother may speak of the "empty nest", the "crowded house" and/or "its revolving front door". She may speak of issues related to the vulnerability of the long term marriage, elder care, or grandparenting, or even disillusionment and disenchantment. The purpose of this research is to explore the identity challenges and prospects of some mothers with young adult-children aged between 18 and 30 years of age in twenty-first century Australia. In interpreting the identity challenges and prospects this particular cohort of mothers encounter in their ordinary, everyday living, a diverse and particular range of maternal experiences.my own included5.have been traced, along with the social and ethical meanings ascribed in them. With an understanding and appreciation of voice as the medium which connects one's inner and outer worlds, this research illuminates the plurality of voices and the multiple layers of meaning in each of these mother's particular living and existing realities. Specifically, this research addresses the narrowly constructed, canonical maternal identity through a critical exploration and reflection on stories, shared in a research context, of the living realities of a group of self-identified "mature", middle-class, Australian mothers with children aged between 18 and 30 years of age6. By appraising the broader familial, historical, social, cultural, institutional, and, importantly, moral contexts in which these mothers are situated, 'thick descriptions' (Geertz 1973, 27)7 of maternal identities, and the challenges and prospects these mothers are negotiating, are provided. In terms of its ethical orientation, the frameworks which support and frame this research reject, repudiate and contest (Nelson 2001) the reduction of ethical concerns to individual or intellectual problems or dilemmas to be solved through the application of a theory derived from reasoned thinking. In dismissing deductive and =theoretical-juridical‘8 approaches, the individualistic orientation entrenched in contemporary Western moral thinking, expressed in the notion of '"what ought I to do" when faced with a problem, issue or dilemma of practical urgency' (Isaacs & Massey 1994, 1), is simultaneously rejected, repudiated and contested (Nelson 2001). In countering such understandings, this research reorients us to the illumination and articulation of who it is good to be, for each of these mothers, in allegiance with those goods which guide and inspire her orientations towards living a good life—a life which embraces and enhances the flourishing of herself and her significant others. With an understanding and appreciation that 'mind is never free of precommitment[—t]here is no innocent eye, nor is there one that penetrates aboriginal reality' (Bruner 1987, 32), this thesis is written with the voices of other interlocutors9. These interlocutors include the voices of my research participants whom I refer to as "research interlocutors", my textual "friends" — those scholars whose work resonates strongly with my orientations—as well as the myriad other voices that speak to mothers, for mothers and about mothers, such as those found in popular and mainstream press and culture. Sometimes these voices resonate; other times dissonance may be heard. In situating this research within these complementary frameworks, this research invites readers to join with me in considering, appreciating and appraising the narrow construction of maternal identity. I seek for this engagement, like the engagements with my research interlocutors, to be 'a meeting of voices, an authentic dialogue that is inclusive of the voices of all concerned participants' (Isaacs 2001, 6). I hope that the voices in this thesis resonate with yours (although, at times, you may feel some dissonance) and that together we can draw closer to the accounting, re-counting and re-stor(y)ing of maternal identities; like concentric circles of witness, the dialogue, ...will thus be expanded rippling into corners where one might both imagine, and least expect. Possibilities, then, are vast; the future exciting (Smith 2007, 397). This research is also shaped and guided by maternal scholarship, a relatively new field of inquiry known as 'motherhood studies' (O'Reilly 2011, xvii) which has its origins within the broader terrain of feminist scholarship. As a work of maternal scholarship, this thesis draws upon and continues the tradition of examining motherhood as it is experienced 'in a social context, as embedded in a political institution: in feminist terms' (Rich 1995, ix). It values mothers, their experiences, their stories, their lives. As such, this research is oriented towards 'matricentric feminism', a particular form of feminist inquiry, politics and theory which is consistent with and receptive to feminist frameworks of care and equal rights (O‘Reilly 2011, 25). A number of complementary conceptual frameworks have been engaged in this research with the thesis presented in three parts: the pre-figurative, configurative and re-configurative. As my particular living experiences provided the initial motivation for this research, an account of the challenges I experienced as a mother with young adult-children are outlined as a Prelude to this thesis. Attention then turns to Part One – Pre-figuring Maternal Identities in which the contextual, conceptual and methodological foundations underpinning this research are explored and outlined. In Chapter One, the prevailing cultural narratives and social discourses supporting and shaping the construction of the canonical maternal identity are outlined. Next, in setting the scholarly context, the critiques — arising from feminist and maternal scholarship — of motherhood as a patriarchal institution, mothering as experience, and mothering as work, are explored. As this research engaged with participants who are embedded in particular middle-class, heterosexual, familial and cultural structures, an exploration of family life cycle theory and main stream media accounts are also incorporated. The terrain in which "mature" mothering within an Australian context is experienced is also outlined, including the notions of "empty nests" and "crowded houses", grandparenting, elder care and women's midlife transition. Chapter Two gives an account of the conceptual ontological, ethical, identity and narrative frameworks underpinning this research. In setting the context for rich interpretations, the characteristics of being human10 are outlined before attention turns to our embodiment and embeddedness in our shared human condition11. From this point, attention then turns to understanding the moral form of human living12. In appreciating the vulnerability inherent in our shared human condition, the ways in which we may experience trouble in our lives is noted. The framing of identity constitution13 as complex, multi-faceted, relationally negotiated and composed is then outlined, followed by an understanding of why narrative is a valuable interpretive tool for interpreting and understanding human experiences. This chapter concludes with an appreciation of the ethical significance of storytelling. The research methodology is then outlined in Chapter Three. The rationale underpinning the adoption of the narrative interviewing technique of in-depth interviewing is explored. In exploring these methodological frameworks, the recruitment and interview processes involved in gathering and interpreting the recorded transcripts of ten Australian mothers with young adult-children are outlined. The method of analysis known as the Listening Guide14 best complements the multi-layered, pluri-vocal nature of narrative accounting. The final section of Chapter Three outlines The Guide, with one mother's recorded transcript used to illustrate this method's step-by-step process. Having gathered an understanding and appreciation of the pluri-vocal, multi-layered nature of narrative and identity constitution, the tone of this thesis changes in Part Two . Configuring Maternal Identities. This section consists of Chapters Four and Five and seeks to find meaning in, and make sense of, the differences and commonalities across these particular accounts. Chapter Four explores the living realities of four Australian mothers with young adult-children: Poppy, Honey, Lily and Heather. In presenting a thick description of these mothers' situated realities, the frameworks.the familial, social, cultural, historical and institutional backgrounds.which have supported and shaped each mother's experiences are illuminated. Simultaneously revealed through these particular accounts are the plurality of goods focusing and moving each mother to the moral form of life, a life of meaning and purpose. The harms challenging some mothers' moral motivations are also revealed in this chapter. Specifically illustrated in Chapter Four are the unique and qualitative differences of particular maternal identity configurations. Chapter Five reveals the commonalities amongst all of the research interlocutors' accounts. This chapter contests the individualistic orientation of many contemporary accounts of motherhood which are aimed at defining or contesting what a "good" mother ought to do. By turning away from such individualistic orientations, the chapter does not seek to define 'the content of obligation' (Taylor 1989, 3) but rather seeks to illuminate and articulate a richer, deeper understanding and appreciation of maternal be-ing and be-coming - that is, who it is good to be, for each of these mothers - in allegiance with those goods that focus and inspire her moral motivations. Part Three - Re-Configuring Maternal Identities, which is comprised of Chapter Six, draws this thesis to a close. In this final chapter, the preconceptions, conditions and aspirations for this mother-centred account of the living realities of a small, local cohort of mothers are reiterated. The insights gathered from the rich, descriptive accounts are illuminated and articulated, and the chapter closes with some suggestions for future research. In a Postlude, I reflect on how this research has been a transformative learning experience in my own life.an experience in which I have been able to not only deeply understand and appreciate the challenges and disorientation I was experiencing but also to identify and reorient my stance in relation to the good. In a practical sense, by offering thick descriptions of the living realities of this cohort of "mature" mothers, this research challenges the canonical maternal identity and questions its relevance for, and effect on, "mature" mothers' identity constitution. By bringing to light the complex existing realities of these particular mothers, this research critiques the canonical maternal identity by illustrating that each mother's life and her identity constitutions are complex, relationally negotiated and composed and that motherhood is an enduring way of being. Through these illustrations, this research engages with and extends understandings of difference feminism. This research, however, not only rejects, repudiates and contests (Nelson 2001) the narrowly defined canonical maternal identity. By illuminating and articulating the goods which shape and inspire these "mature" mothers' motherwork, this research offers a matricentric account which is consistent with and respectful of the particular, situated realities—the broader familial, social, institutional, but most importantly, moral values and frameworks—in which each mother‘s life is embedded and her motherwork oriented. By understanding and appreciating the complex and multiple webs of relationships in which each mother exists, this matricentric re-stor(y)ing of maternal experiences not only understands and appreciates the unique nature of each mother‘s existing realities, it is oriented to the continuing enhancing of the shared pursuit of the good which underpins particular maternal practices and particular maternal ways of being.

Symmetry of in-shoe force signatures in athletes under field conditions : an application for injury prevention

The aetiology behind overuse injuries such as stress fractures is complex and multi-factorial. In sporting events where the loading is likely to be uneven (e.g. hurdling and jumps), research has suggested that the frequency of stress fractures seems to favour the athlete’s dominant limb. The tendency for an individual to have a preferred limb for voluntary motor acts makes limb selection a possible factor behind the development of unilateral overuse injuries, particularly when repeatedly used during high loading activities. The event of sprint hurdling is well suited for the study of loading asymmetry as the hurdling technique is repetitive and the limb movement asymmetrical. Of relevance to this study is the high incidence of Navicular Stress Fractures (NSF) in hurdlers, with suggestions there is a tendency for the fracture to develop in the trail leg foot, although this is not fully accepted. The Ground Reaction Force (GRF) with each foot contact is influenced by the hurdle action, with research finding step-to-step loading variations. However, it is unknown if this loading asymmetry extends to individual forefoot joints, thereby influencing stress fracture development. The first part of the study involved a series of investigations using a commercially available matrix style in-shoe sensor system (FscanTM, Tekscan Inc.). The suitability of insole sensor systems and custom made discrete sensors for use in hurdling-related training activities was assessed. The methodology used to analyse foot loading with each technology was investigated. The insole and discrete sensors systems tested proved to be unsuitable for use during full pace hurdling. Instead, a running barrier task designed to replicate the four repetitive foot contacts present during hurdling was assessed. This involved the clearance of a series of 6 barriers (low training hurdles), place in a straight line, using 4 strides between each. The second part of the study involved the analysis of "inter-limb" and "within foot loading asymmetries" using stance duration as well as vertical GRF under the Hallux (T1), the first metatarsal head (M1) and the central forefoot peak pressure site (M2), during walking, running, and running with barrier clearances. The contribution to loading asymmetry that each of the four repetitive foot contacts made during a series of barrier clearances was also assessed. Inter-limb asymmetry, in forefoot loading, occurred at discrete forefoot sites in a non-uniform manner across the three gait conditions. When the individual barrier foot contacts were compared, the stance duration was asymmetrical and the proportion of total forefoot load at M2 was asymmetrical. There were no significant differences between the proportion of forefoot load at M1, compared to M2; for any of the steps involved in the barrier clearance. A case study testing experimental (discrete) sensors during full pace sprinting and hurdling found that during both gait conditions, the trail limb experienced the greater vertical GRF at M1 and M2. During full pace hurdling, increased stance duration and vertical loading was a characteristic of the trail limb hurdle foot contacts. Commercially available in-shoe systems are not suitable for on field assessment of full pace hurdling. For the use of discrete sensor technology to become commonplace in the field, more robust sensors need to be developed.

Orals ain’t orals : the role of prepared oral presentations in the classroom and beyond. How do instruction and feedback practices guide delivery choices?

Despite an ostensibly technology-driven society, the ability to communicate orally continues to feature as an essential ability for students at school and university, as it is for graduates in the workplace. Pedagogically, one rationale is that the need to develop effective oral communication skills is tied to life-long learning which includes successful participation in future work-related tasks. One tangible way that educators have assessed proficiency in the area of communication is through prepared oral presentations. While much of the literature uses the terms 'oral communication' and 'oral presentation' interchangeably, some writers question the role more formal presentations play in the overall development of oral communication skills. However, such formal speaking tasks continue to be a recognised assessment practice in both the secondary school and academy, and, therefore, worthy of further investigation. Adding to the discussion, this thesis explores the knowledge and skills students bring into the academy from previous educational experiences. It examines some of the teaching and assessment methods used in secondary schools to develop oral communication skills through the use of formal oral presentations. Specifically, it investigates criterion-referenced assessment sheets and how these tools are used as a form of instruction, as well as their role and effectiveness in the evaluation of student ability. The focus is on the student's perspective and includes 12 semi-structured interviews with school students. The purpose of this thesis is to explore key thematics underpinning oral communication and to identify tensions between expectations and practice. While acknowledging the breadth and depth of material available under the heading of 'communication theory', this study specifically draws on an expanded view of the rhetorical tradition to fully interrogate the assumptions supporting the practice of assessing oral presentations. Finally, this thesis recommends reconnecting with an updated understanding of rhetoric as a way of assisting in the development of expressive, articulate and discerning communicators.

Scientific Research in Information Systems : A Beginner's Guide

- ​Covers entire research process from start to end - Places particular emphasis on motivational components, modes of inquiry in scholarly conduct, theorizing and planning research - Includes aspects such as publication and ethical challenges This book is designed to introduce doctoral and other higher-degree research students to the process of scientific research in the fields of Information Systems as well as fields of Information Technology, Business Process Management and other related disciplines within the social sciences. It guides research students in their process of learning the life of a researcher. In doing so, it provides an understanding of the essential elements, concepts and challenges of the journey into research studies. It also provides a gateway for the student to inquire deeper about each element covered​. Comprehensive and broad but also succinct and compact, the book is focusing on the key principles and challenges for a novice doctoral student.

Application of high voltage, high frequency pulsed electromagnetic field on cortical bone tissue

Over the last few decades, electric and electromagnetic fields have achieved important role as stimulator and therapeutic facility in biology and medicine. In particular, low magnitude, low frequency, pulsed electromagnetic field has shown significant positive effect on bone fracture healing and some bone diseases treatment. Nevertheless, to date, little attention has been paid to investigate the possible effect of high frequency, high magnitude pulsed electromagnetic field (pulse power) on functional behaviour and biomechanical properties of bone tissue. Bone is a dynamic, complex organ, which is made of bone materials (consisting of organic components, inorganic mineral and water) known as extracellular matrix, and bone cells (live part). The cells give the bone the capability of self-repairing by adapting itself to its mechanical environment. The specific bone material composite comprising of collagen matrix reinforced with mineral apatite provides the bone with particular biomechanical properties in an anisotropic, inhomogeneous structure. This project hypothesized to investigate the possible effect of pulse power signals on cortical bone characteristics through evaluating the fundamental mechanical properties of bone material. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses up to 500 V and 10 kHz. Bone shows distinctive characteristics in different loading mode. Thus, functional behaviour of bone in response to pulse power excitation were elucidated by using three different conventional mechanical tests applying three-point bending load in elastic region, tensile and compressive loading until failure. Flexural stiffness, tensile and compressive strength, hysteresis and total fracture energy were determined as measure of main bone characteristics. To assess bone structure variation due to pulse power excitation in deeper aspect, a supplementary fractographic study was also conducted using scanning electron micrograph from tensile fracture surfaces. Furthermore, a non-destructive ultrasonic technique was applied for determination and comparison of bone elasticity before and after pulse power stimulation. This method provided the ability to evaluate the stiffness of millimetre-sized bone samples in three orthogonal directions. According to the results of non-destructive bending test, the flexural elasticity of cortical bone samples appeared to remain unchanged due to pulse power excitation. Similar results were observed in the bone stiffness for all three orthogonal directions obtained from ultrasonic technique and in the bone stiffness from the compression test. From tensile tests, no significant changes were found in tensile strength and total strain energy absorption of the bone samples exposed to pulse power compared with those of the control samples. Also, the apparent microstructure of the fracture surfaces of PP-exposed samples (including porosity and microcracks diffusion) showed no significant variation due to pulse power stimulation. Nevertheless, the compressive strength and toughness of millimetre-sized samples appeared to increase when the samples were exposed to 66 hours high power pulsed electromagnetic field through screws with small contact cross-section (increasing the pulsed electric field intensity) compare to the control samples. This can show the different load-bearing characteristics of cortical bone tissue in response to pulse power excitation and effectiveness of this type of stimulation on smaller-sized samples. These overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electromagnetic field at 500 V and 10 kHz through capacitive coupling method, was athermal and did not damage the bone tissue construction.

Global flash multifocal electroretinogram : early detection of local functional changes and its correlations with optical coherence tomography and visual field loss in diabetic eyes

Purpose: To investigate the correlations of the global flash multifocal electroretinogram (MOFO mfERG) with common clinical visual assessments – Humphrey perimetry and Stratus circumpapillary retinal nerve fiber layer (RNFL) thickness measurement in type II diabetic patients. Methods: Forty-two diabetic patients participated in the study: ten were free from diabetic retinopathy (DR) while the remainder suffered from mild to moderate non-proliferative diabetic retinopathy (NPDR). Fourteen age-matched controls were recruited for comparison. MOFO mfERG measurements were made under high and low contrast conditions. Humphrey central 30-2 perimetry and Stratus OCT circumpapillary RNFL thickness measurements were also performed. Correlations between local values of implicit time and amplitude of the mfERG components (direct component (DC) and induced component (IC)), and perimetric sensitivity and RNFL thickness were evaluated by mapping the localized responses for the three subject groups. Results: MOFO mfERG was superior to perimetry and RNFL assessments in showing differences between the diabetic groups (with and without DR) and the controls. All the MOFO mfERG amplitudes (except IC amplitude at high contrast) correlated better with perimetry findings (Pearson’s r ranged from 0.23 to 0.36, p<0.01) than did the mfERG implicit time at both high and low contrasts across all subject groups. No consistent correlation was found between the mfERG and RNFL assessments for any group or contrast conditions. The responses of the local MOFO mfERG correlated with local perimetric sensitivity but not with RNFL thickness. Conclusion: Early functional changes in the diabetic retina seem to occur before morphological changes in the RNFL.

The effect of very small air gaps on small field dosimetry

The purpose of this study was to investigate the effect of very small air gaps (less than 1 mm) on the dosimetry of small photon fields used for stereotactic treatments. Measurements were performed with optically stimulated luminescent dosimeters (OSLDs) for 6 MV photons on a Varian 21iX linear accelerator with a Brainlab μMLC attachment for square field sizes down to 6 mm × 6 mm. Monte Carlo simulations were performed using EGSnrc C++ user code cavity. It was found that the Monte Carlo model used in this study accurately simulated the OSLD measurements on the linear accelerator. For the 6 mm field size, the 0.5 mm air gap upstream to the active area of the OSLD caused a 5.3 % dose reduction relative to a Monte Carlo simulation with no air gap. A hypothetical 0.2 mm air gap caused a dose reduction > 2 %, emphasizing the fact that even the tiniest air gaps can cause a large reduction in measured dose. The negligible effect on an 18 mm field size illustrated that the electronic disequilibrium caused by such small air gaps only affects the dosimetry of the very small fields. When performing small field dosimetry, care must be taken to avoid any air gaps, as can be often present when inserting detectors into solid phantoms. It is recommended that very small field dosimetry is performed in liquid water. When using small photon fields, sub-millimetre air gaps can also affect patient dosimetry if they cannot be spatially resolved on a CT scan. However the effect on the patient is debatable as the dose reduction caused by a 1 mm air gap, starting out at 19% in the first 0.1 mm behind the air gap, decreases to < 5 % after just 2 mm, and electronic equilibrium is fully re-established after just 5 mm.

An investigation on the accuracy of regional ocean models through field trials

Recent efforts in mission planning for underwater vehicles have utilised predictive models to aid in navigation, optimal path planning and drive opportunistic sampling. Although these models provide information at a unprecedented resolutions and have proven to increase accuracy and effectiveness in multiple campaigns, most are deterministic in nature. Thus, predictions cannot be incorporated into probabilistic planning frameworks, nor do they provide any metric on the variance or confidence of the output variables. In this paper, we provide an initial investigation into determining the confidence of ocean model predictions based on the results of multiple field deployments of two autonomous underwater vehicles. For multiple missions conducted over a two-month period in 2011, we compare actual vehicle executions to simulations of the same missions through the Regional Ocean Modeling System in an ocean region off the coast of southern California. This comparison provides a qualitative analysis of the current velocity predictions for areas within the selected deployment region. Ultimately, we present a spatial heat-map of the correlation between the ocean model predictions and the actual mission executions. Knowing where the model provides unreliable predictions can be incorporated into planners to increase the utility and application of the deterministic estimations.

Wide-field assessment of the human corneal subbasal nerve plexus in diabetic neuropathy using a novel mapping technique

To develop a rapid optimized technique of wide-field imaging of the human corneal subbasal nerve plexus. A dynamic fixation target was developed and, coupled with semiautomated tiling software, a rapid method of capturing and montaging multiple corneal confocal microscopy images was created. To illustrate the utility of this technique, wide-field maps of the subbasal nerve plexus were produced in 2 participants with diabetes, 1 with and 1 without neuropathy. The technique produced montages of the central 3 mm of the subbasal corneal nerve plexus. The maps seem to show a general reduction in the number of nerve fibers and branches in the diabetic participant with neuropathy compared with the individual without neuropathy. This novel technique will allow more routine and widespread use of subbasal nerve plexus mapping in clinical and research situations. The significant reduction in the time to image the corneal subbasal nerve plexus should expedite studies of larger groups of diabetic patients and those with other conditions affecting nerve fibers. The inferior whorl and the surrounding areas may show the greatest loss of nerve fibers in individuals with diabetic neuropathy, but this should be further investigated in a larger cohort.

Visual sensitivity loss in the central thirty degrees of visual field is associated with diabetic peripheral neuropathy

Aims/hypothesis: Impaired central vision has been shown to predict diabetic peripheral neuropathy (DPN). Several studies have demonstrated diffuse retinal neurodegenerative changes in diabetic patients prior to retinopathy development, raising the prospect that non-central vision may also be compromised by primary neural damage. We hypothesise that type 2 diabetic patients with DPN exhibit visual sensitivity loss in a distinctive pattern across the visual field, compared with a control group of type 2 diabetic patients without DPN. Methods: Increment light sensitivity was measured by standard perimetry in the central 30 degree of visual field for two age-matched groups of type 2 diabetic patients, with and without neuropathy (n=40/30). Neuropathy status was assigned using the neuropathy disability score. Mean visual sensitivity values were calculated globally, for each quadrant and for three eccentricities (0-10 degree , 11-20 degree and 21-30 degree ). Data were analysed using a generalised additive mixed model (GAMM). Results: Global and quadrant between-group visual sensitivity mean differences were marginally but consistently lower (by about 1 dB) in the neuropathy cohort compared with controls. Between-group mean differences increased from 0.36 to 1.81 dB with increasing eccentricity. GAMM analysis, after adjustment for age, showed these differences to be significant beyond 15 degree eccentricity and monotonically increasing. Retinopathy levels and disease duration were not significant factors within the model (p=0.90). Conclusions/interpretation: Visual sensitivity reduces disproportionately with increasing eccentricity in type 2 diabetic patients with peripheral neuropathy. This sensitivity reduction within the central 30 degree of visual field may be indicative of more consequential loss in the far periphery.

Performance evaluation of onsite wastewater treatment : field sampling and preliminary evaluation of results

Background The onsite treatment of sewage and effluent disposal within the premises is widely prevalent in rural and urban fringe areas due to the general unavailability of reticulated wastewater collection systems. Despite the seemingly low technology of the systems, failure is common and in many cases leading to adverse public health and environmental consequences. Therefore it is important that careful consideration is given to the design and location of onsite sewage treatment systems. It requires an understanding of the factors that influence treatment performance. The use of subsurface effluent absorption systems is the most common form of effluent disposal for onsite sewage treatment and particularly for septic tanks. Additionally in the case of septic tanks, a subsurface disposal system is generally an integral component of the sewage treatment process. Therefore location specific factors will play a key role in this context. The project The primary aims of the research project are: • to relate treatment performance of onsite sewage treatment systems to soil conditions at site; • to identify important areas where there is currently a lack of relevant research knowledge and is in need of further investigation. These tasks were undertaken with the objective of facilitating the development of performance based planning and management strategies for onsite sewage treatment. The primary focus of the research project has been on septic tanks. Therefore by implication the investigation has been confined to subsurface soil absorption systems. The design and treatment processes taking place within the septic tank chamber itself did not form a part of the investigation. In the evaluation to be undertaken, the treatment performance of soil absorption systems will be related to the physico-chemical characteristics of the soil. Five broad categories of soil types have been considered for this purpose. The number of systems investigated was based on the proportionate area of urban development within the Brisbane region located on each soil types. In the initial phase of the investigation, though the majority of the systems evaluated were septic tanks, a small number of aerobic wastewater treatment systems (AWTS) were also included. This was primarily to compare the effluent quality of systems employing different generic treatment processes. It is important to note that the number of different types of systems investigated was relatively small. As such this does not permit a statistical analysis to be undertaken of the results obtained. This is an important issue considering the large number of parameters that can influence treatment performance and their wide variability. The report This report is the second in a series of three reports focussing on the performance evaluation of onsite treatment of sewage. The research project was initiated at the request of the Brisbane City Council. The work undertaken included site investigation and testing of sewage effluent and soil samples taken at distances of 1 and 3 m from the effluent disposal area. The project component discussed in the current report formed the basis for the more detailed investigation undertaken subsequently. The outcomes from the initial studies have been discussed, which enabled the identification of factors to be investigated further. Primarily, this report contains the results of the field monitoring program, the initial analysis undertaken and preliminary conclusions. Field study and outcomes Initially commencing with a list of 252 locations in 17 different suburbs, a total of 22 sites in 21 different locations were monitored. These sites were selected based on predetermined criteria. To obtain house owner agreement to participate in the monitoring study was not an easy task. Six of these sites had to be abandoned subsequently due to various reasons. The remaining sites included eight septic systems with subsurface effluent disposal and treating blackwater or combined black and greywater, two sites treating greywater only and six sites with AWTS. In addition to collecting effluent and soil samples from each site, a detailed field investigation including a series of house owner interviews were also undertaken. Significant observations were made during the field investigations. In addition to site specific observations, the general observations include the following: • Most house owners are unaware of the need for regular maintenance. Sludge removal has not been undertaken in any of the septic tanks monitored. Even in the case of aerated wastewater treatment systems, the regular inspections by the supplier is confined only to the treatment system and does not include the effluent disposal system. This is not a satisfactory situation as the investigations revealed. • In the case of separate greywater systems, only one site had a suitably functioning disposal arrangement. The general practice is to employ a garden hose to siphon the greywater for use in surface irrigation of the garden. • In most sites, the soil profile showed significant lateral percolation of effluent. As such, the flow of effluent to surface water bodies is a distinct possibility. • The need to investigate the subsurface condition to a depth greater than what is required for the standard percolation test was clearly evident. On occasion, seemingly permeable soil was found to have an underlying impermeable soil layer or vice versa. The important outcomes from the testing program include the following: • Though effluent treatment is influenced by the physico-chemical characteristics of the soil, it was not possible to distinguish between the treatment performance of different soil types. This leads to the hypothesis that effluent renovation is significantly influenced by the combination of various physico-chemical parameters rather than single parameters. This would make the processes involved strongly site specific. • Generally the improvement in effluent quality appears to take place only within the initial 1 m of travel and without any appreciable improvement thereafter. This relates only to the degree of improvement obtained and does not imply that this quality is satisfactory. This calls into question the value of adopting setback distances from sensitive water bodies. • Use of AWTS for sewage treatment may provide effluent of higher quality suitable for surface disposal. However on the whole, after a 1-3 m of travel through the subsurface, it was not possible to distinguish any significant differences in quality between those originating from septic tanks and AWTS. • In comparison with effluent quality from a conventional wastewater treatment plant, most systems were found to perform satisfactorily with regards to Total Nitrogen. The success rate was much lower in the case of faecal coliforms. However it is important to note that five of the systems exhibited problems with regards to effluent disposal, resulting in surface flow. This could lead to possible contamination of surface water courses. • The ratio of TDS to EC is about 0.42 whilst the optimum recommended value for use of treated effluent for irrigation should be about 0.64. This would mean a higher salt content in the effluent than what is advisable for use in irrigation. A consequence of this would be the accumulation of salts to a concentration harmful to crops or the landscape unless adequate leaching is present. These relatively high EC values are present even in the case of AWTS where surface irrigation of effluent is being undertaken. However it is important to note that this is not an artefact of the treatment process but rather an indication of the quality of the wastewater generated in the household. This clearly indicates the need for further research to evaluate the suitability of various soil types for the surface irrigation of effluent where the TDS/EC ratio is less than 0.64. • Effluent percolating through the subsurface absorption field may travel in the form of dilute pulses. As such the effluent will move through the soil profile forming fronts of elevated parameter levels. • The downward flow of effluent and leaching of the soil profile is evident in the case of podsolic, lithosol and kransozem soils. Lateral flow of effluent is evident in the case of prairie soils. Gleyed podsolic soils indicate poor drainage and ponding of effluent. In the current phase of the research project, a number of chemical indicators such as EC, pH and chloride concentration were employed as indicators to investigate the extent of effluent flow and to understand how soil renovates effluent. The soil profile, especially texture, structure and moisture regime was examined more in an engineering sense to determine the effect of movement of water into and through the soil. However it is not only the physical characteristics, but the chemical characteristics of the soil also play a key role in the effluent renovation process. Therefore in order to understand the complex processes taking place in a subsurface effluent disposal area, it is important that the identified influential parameters are evaluated using soil chemical concepts. Consequently the primary focus of the next phase of the research project will be to identify linkages between various important parameters. The research thus envisaged will help to develop robust criteria for evaluating the performance of subsurface disposal systems.

Field measurement of wheel-rail impact force at insulated rail joint

When wheels pass over insulated rail joints (IRJs) a vertical impact force is generated. The ability to measure the impact force is valuable as the force signature helps understand the behaviour of the IRJs, in particular their potential for failure. The impact forces are thought to be one of the main factors that cause damage to the IRJ and track components. Study of the deterioration mechanism helps finding new methods to improve the service life of IRJs in track. In this research, the strain-gage-based wheel load detector, for the first time, is employed to measure the wheel–rail contact-impact force at an IRJ in a heavy haul rail line. In this technique, the strain gages are installed within the IRJ assembly without disturbing the structural integrity of IRJ and arranged in a full wheatstone bridge to form a wheel load detector. The instrumented IRJ is first tested and calibrated in the lab and then installed in the field. For comparison purposes, a reference rail section is also instrumented with the same strain gage pattern as the IRJ. In this paper the measurement technique, the process of instrumentation, and tests as well as some typical data obtained from the field and the inferences are presented.