Preparation and characterisation of new titanium based alloys for orthopaedic and dental applications

Various types of titanium alloys with high strength and low elastic modulus and, at the same time, vanadium and aluminium free have been developed as surgical biomaterials in recent years. Moreover, porous metals are promising hard tissue implants in orthopaedic and dentistry, where they mimic the porous structure and the low elastic modulus of natural bone. In the present study, new biocompatible Ti-based alloy foams with approximate relative densities of 0.4, in which Sn and Nb were added as alloying metals, were synthesised through powder metallurgy method.
The new alloys were prepared by mechanical alloying and subsequently sintered at high temperature using a vacuum furnace. The characteristics and the processability of the ball milled powders and the new porous titanium-based alloys were characterised by X-ray diffraction, optical
microscopy and scanning electron microscopy .The mechanical properties of the new titanium alloys were examined by Vickers microhardness measurements and compression testing.

A preliminary study on machinability of super austenitic stainless steel

Stainless steel is the most widely used alloys of steel. The reputed variety of stainless steel having customised material properties as per the design requirements is Duplex Stainless Steel and Austenitic Stainless Steel. The Austenite Stainless Steel alloy has been developed further to be Super Austenitic Stainless Steel (SASS) by increasing the percentage of the alloying elements to form the half or more than the half of the material composition. SASS (Grade-AL-6XN) is an alloy steel containing high percentages of nickel (24%), molybdenum (6%) and chromium (21%). The chemical elements offer high degrees of corrosion resistance, toughness and stability in a large range of hostile environments like petroleum, marine and food processing industries. SASS is often used as a commercially viable substitute to high cost non-ferrous or non-metallic metals. The ability to machine steel effectively and efficiently is of utmost importance in the current competitive market. This paper is an attempt to evaluate the machinability of SASS which has been a classified material so far with very limited research conducted on it. Understanding the machinability of this alloy would assist in the effective forming of this material by metal cutting. The novelty of research associated with this is paper is reasonable taking into consideration the unknowns involved in machining SASS. The experimental design consists of conducting eight milling trials at combination of two different feed rates, 0.1 and 0.15 mm/tooth; cutting speeds, 100 and 150 m/min; Depth of Cut (DoC), 2 and 3 mm and coolant on for all the trials. The cutting tool has two inserts and therefore has two cutting edges. The trial sample is mounted on a dynamometer (type 9257B) to measure the cutting forces during the trials. The cutting force data obtained is later analyzed using DynaWare supplied by Kistler. The machined sample is subjected to surface roughness (Ra) measurement using a 3D optical surface profilometer (Alicona Infinite Focus). A comprehensive metallography process consisting of mounting, polishing and etching was conducted on a before and after machined sample in order to make a comparative analysis of the microstructural changes due to machining. The microstructural images were capture using a digital microscope. The microhardness test were conducted on a Vickers scale (Hv) using a Vickers microhardness tester. Initial bulk hardness testing conducted on the material show that the alloy is having a hardness of 83.4 HRb. This study expects an increase in hardness mostly due to work hardening may be due to phase transformation. The results obtained from the cutting trials are analyzed in order to judge the machinability of the material. Some of the criteria used for machinability evaluation are cutting force analysis, surface texture analysis, metallographic analysis and microhardness analysis. The methodology followed in each aspect of the investigation is similar to and inspired by similar research conducted on other materials. However, the novelty of this research is the investigation of various aspects of machinability and drawing comparisons between each other while attempting to justify each result obtained to the microstructural changes observed which influence the behaviour of the alloy. Due to the limited scope of the paper, machinability criteria such as chip morphology, Metal Removal Rate (MRR) and tool wear are not included in this paper. All aspects are then compared and the optimum machining parameters are justified with a scope for future investigations

Plastic deformation in Zr41 Ti14 Cu12.5 Ni10 Be22.5 bulk metal glass under vickers indenter

Vickers indentation was conducted on an as-cast Zr41Ti14Cu12.5Ni10Be22.5 bulk metal glass (BMG) to study shear band formation using a bonded interface technique. The results indicate that the plastic deformation in the BMG is accommodated by the semi-circular (primary) and radial (secondary) shear bands. The inter-band spacing of the semi-circular shear bands is found to be independent of the applied load. The measured size of the deformation zone is in good agreement with the prediction of the theoretical model proposed by Zhang et al.

Plastic deformation in a partially crystallized Zr-based BMG under Vickers indenter

Vickers indentations were carried out on an anneal-introduced partially crystallized Zr₄₁Ti₁₄Cu_12.5 Ni₁₀Be_22.5 bulk metallic glass (BMG), and the evolution of the shear bands in this samplewas investigated and compared to the as-cast, aswell as the structurally relaxed counterparts. The results indicate that the plastic deformation in the partially crystallized BMG was accommodated by the semi-circular (primary) and radial (secondary) shear bands. A full crack or flake that was produced due to the spring back during the load removal was observed. The shear band density in the annealed alloy which was dispersed with crystalliteswas significantly lower than that of the as-cast alloy. The difference of the shear band features among the three kinds of alloy status, i.e., partially crystallized, structurally relaxed and as-cast alloys was discussed in terms of the free volume in the BMGs and the characteristics of nano-composites. It has been demonstrated that the plasticity for the three statuses of alloys queues in the descending order as the as-cast, annealed with partial crystallization, and annealed without crystallization.

Preparation, characterization and dielectric properties of temperature stable SrTiO3/PEEK composites for microwave substrate applications

Poly(ether ether ketone) (PEEK) is a potential candidate for electronic applications due to its low permittivity, low loss, high melting point, better chemical resistance, excellent insulating properties and easy processibility. Present paper discusses the preparation and characterization of SrTiO3 filled PEEK composite for microwave substrate applications. The dielectric constant, dielectric loss and temperature variation of dielectric constant of the composites have been studied up to 1 MHz using an Impedance Analyzer. Different theoretical approaches have been employed to predict the effective permittivity of composite systems and the results are compared with that of the experimental data. The crystallinity of the bulk composite is studied by X-ray diffraction studies. Scanning electron microscopic technique has been employed to study the dispersion of the particulate filler in PEEK matrix. Vickers hardness of pure and filled PEEK composite has been measured using Microhardness Tester. The effect of particle size on the dielectric as well as mechanical properties of SrTiO3/PEEK composite system is also studied by incorporating micronsize and nanosize fillers. Present study shows that a temperature stable composite can be realized by judiciously selecting appropriate filler concentration in the PEEK matrix.

Working in teams : the influence of rhetoric-from sensemaking to sadness

At a time when teams are increasingly and routinely being used in Public Administration (PA) organizations, the prevailing wisdom about teams continues to confirm that teams axiomatically bring increases and improvements in effectiveness, productivity and communication. There has been relatively little critical address of whether these benefits actually accrue, nor what the experience of team members actually is. The PA literature, in particular, remains silent on this important issue. This paper shares findings from an exploratory phenomenological study. Members of teams in organizations were interviewed and asked about their experiences of working in teams. In contrast to the current wisdom, not only did team members not report the anticipated improvements and benefits, their stories tended to highlight the negative influence that the rhetoric surrounding teams might have on individuals. This paper shares the responses of team members to that rhetoric, revealing themes of "Teams, Rhetoric and Sensemaking," a challenge to the notion of "Teams as One Big Happy Family?" while identifying "Teams as Crucibles of Resignation and Sadness." These findings indicate the continuing need for further research into understanding the experience of individuals within various team and organizational structures, especially as they operate in PA organizations.

An assault on identity : the male view of being made redundant

Participation and success in paid work is a key element of identity for many men. The increased prevalence of downsizing, and the discarding of individuals from organisations, therefore has particular pertinence when considering men’s workplace experiences. This paper discusses findings from an exploratory study investigating the experiences of Australian executives who had been made redundant. Three themes related to male identity are presented: the impact on respondents’ positions as breadwinners for their families; a concern for being seen to be capable and in control; and perceptions of loss of status upon returning to work. These executives expressed feelings of anger, sadness, fear and embarrassment as a result of the assault to their identity. There is a need for continued focus on these experiences and their implications for both men and women, particularly as individuals report undergoing multiple redundancies.

Integration or collision? : middle managers' concerns for work-life balance

As increased work demands and longer working hours become the reality for many employees, the concept of work-life balance has received increasing attention. This paper presents findings from an exploratory study of Australian middle managers, which investigated the impact of middle managers’ daily organisational experiences on their lives both in and beyond the workplace. We focus on respondents’ concerns for the encroachment of work on their personal lives, both through the advent of new technologies and the introduction of flexibility initiatives in the workplace. The unwelcome effects of frustration, stress and fatigue highlight the need for organisations to gain a better understanding of employees’ experiences related to work-life balance.

Work teams: perceptions of a ready-made support system?

Much research on work teams has been focused at the team-Ievel,  considering such issues as effectiveness, productivity and overall  interaction. Using qualitative in-depth interviews, the author has asked the question: what is the experience of the individual working within a team? This paper discusses one theme to have emerged, that of perceived emotional support being provided within the team. Respondents' descriptions of emotional support are discussed in terms of acceptance and respect, and of caring. The discussion shows how the provision of this support has implications for how individuals view teams in general, and indicates areas for future research.

Working in teams: the influence of rhetoric-from sensemaking to sadness

The prevailing wisdom tells us that teams axiomatically bring increases and improvements in effectiveness, productivity and communication. There has been too little critical address of whether these benefits actually accrue, nor what the experience of team members actually is. This paper shares findings from a Heideggerian phenomenological study, where members of teams in organizations were interviewed and asked about their experiences of working in teams. Astonishingly, not only did team members not report these anticipated improvements, their stories tended to highlight the negative influence that the rhetoric surrounding teams might have on individuals. This paper shares the responses of team members to that rhetoric, revealing themes of "Teams, Rhetoric and Sensemaking", a challenge to the notion of "Teams as One Big Happy Family?", and "Teams as Crucibles of Resignation and Sadness". These findings indicate the need for future research into understanding the experience of individuals within various team and organizational structures.

Managing in the middle: a review of the mddle management experience in the 21st century

Downsizing and organisational restructuring have impacted both the role and the number of middle managers in organisations. .This paper provides a review of recent research on middle management to seek an understanding of the current situation for middle managers as they face the start of the 2rt century. The literature review is presented in two parts - focusing on the position of middle managers as they emerge from downsizing, and drawing attention to the special circumstances for managers "in the middle". The research points to some of the challenges middle managers' experience as they work, live, and survive organisational life, as well as highlighting the need for ongoing investigation of their individual experiences.

Working mothers of children with chronic illness: narratives of working and caring

This paper reports the initial findings of an exploratory, qualitative study of the life and work of people who are working full-time and also caring for a child with chronic illness. The demands of such a lifestyle are significant. Respondents - all women - often reported 'doing-it-all' while constantly being frustrated and challenged in their mothering role.

Towards ending the silence: working women as carers of children with chronic illness/disability

This research presents stories from Australian women who work and care for a child with a significant chronic illness or disability. The paper considers the theory of Silencing the Self (Jack, 1991) in relation to the reported experiences and behaviours of these women. We report three themes of Caring and Working: "Otherness", "Doing it All" - but "Wanting to Live a Normal Life". As in Jack's study, these women engaged in silencing of the self. However, we also observed other people contributing to their silence and, unlike the respondents in Jack's study, many of these women fought the silence and did not accept that their unhappy situations should continue. They sought a life where silencing may not have been necessary.

"Your job no longer exists!" from experiences of alienation to expectations of resilience - a phenomenological study

We have entered the age of the contingent or temporary worker, the consultant and the subcontractor. Workers are expected to be pliable and tractable; to “fit in.” Being made redundant is also an area where modern workers are expected to be flexible and resilient. However, when these so-called “flexible” workers are told their job no longer exists, the accompanying sense of rejection and alienation can be excruciating. Stories of being made redundant were collected during an exploratory, qualitative study, using Heideggerian phenomenology as the methodological vehicle to capture the lived experiences of those affected. Focused, in-depth interviews were conducted with the ten respondents; nine men and one woman. The stories shared suggest that being made redundant is an alienating experience with respondents sharing feelings of powerlessness, shock, betrayal, shame and social isolation. Unfortunately, those having experienced redundancy were also not as resilient as is routinely assumed. They did not “bounce back” unchanged, but reported significant negative outcomes including fear for the future, underemployment, family disruptions and an erosion of trust. Recommendations are made orienting organisations towards a more human process of redundancy.

Stories of ambivalence : Australian executives' experiences of outplacement services

The increasing prevalence of organizational downsizing has been matched by growth in the provision of outplacement services. Yet there has been limited research on either the effectiveness of these programs or the experience of individuals undertaking them. Within a qualitative study investigating the experiences of Australian executives who had been made redundant, one of the focus areas explored was the experience of using outplacement services. Respondents' stories revealed a sense of ambivalence towards these programs. This paper discusses the conflicting experiences giving rising to this ambivalence, namely, positive outcomes with respect to the use of office services and the receiving of proactive support, and more negative aspects of an absence of counselling skills and impersonal treatment through the organizational exit process. It is argued that further research on the outplacement experience is required to determine the type and quality of services which will best serve those who have been made redundant.