Analysis of spherical indentation of superelastic shape memory alloys

Dimensional analysis and the finite element method are applied in this paper to study spherical indentation of superelastic shape memory alloys. The scaling relationships derived from dimensional analysis bridge the indentation response and the mechanical properties of a superelastic shape memory alloy. Several key variables of a superelastic indentation curve are revealed and examined. We prove that the bifurcation force in a superelastic indentation curve only relies on the forward transformation stress and the elastic properties of the initial austenite; and the return force in a superelastic indentation curve only relies on the reverse transformation stress and the elastic properties of the initial austenite. Furthermore, the dimensionless functions to determine the bifurcation force and the return force are proved to be identical. These results not only enhance our understanding of spherical indentation of superelastic shape memory alloys, but also provide the theoretical basis for developing a practicable method to calibrate the mechanical properties of a superelastic material from the spherical indentation test.

Processing and mechanical properties of porous titanium-niobium shape memory alloy for biomedical applications

Ti-26 at.%Nb (hereafter Ti-26Nb) alloy foams were fabricated by space-holder sintering process. The porous structures of the foams were characterized by scanning electron microscopy (SEM). The mechanical properties of the Ti-26Nb foam samples were investigated using compressive test. Results indicate that mechanical properties of Ti-26Nb foam samples are influenced by foam porosity. The plateau stresses and elastic moduli of the foams under compression decrease with the increase of their porosities. The plateau stresses and elastic moduli are measured to be from 10~200 MPa and 0.4~5.0 GPa for the Ti-26Nb foam samples with porosities ranged from 80~50 %, respectively.

Nanofretting behaviors of NiTi shape memory alloy

Nanofretting refers to cyclic movements of contact interfaces with the relative displacement amplitude at the nanometer scale, where the contact area and normal load are usually much smaller than those in fretting. Nanofretting widely exists in microelctromechanical systems (MEMS) and may become a key tribological concern besides microwear and adhesion. With a triboindenter, the nanofretting behaviors of a nickel titanium (NiTi) shape memory alloy are studied under various normal loads (1–10 mN) and tangential displacement amplitudes (2–500 nm) by using a spherical diamond tip. Similar to fretting, the nanofretting of NiTi/diamond pair can also be divided into different regimes upon various shapes of tangential force–displacement curves. The dependence of nanofretting regime on the normal load and the displacement amplitude can be summarized in a running condition nanofretting map. However, due to the surface and size effects, nanofretting operates at some different conditions, such as improved mechanical properties of materials at the nanometer scale, small apparent contact area and single-asperity contact behavior. Consequently, different from fretting, nanofretting was found to exhibit several unique behaviors: (i) the maximum tangential force in one cycle is almost unchanged during a nanofretting test, which is different from a fretting test where the maximum tangential force increases rapidly in the first dozens of cycles; (ii) the tangential stiffness in nanofretting is three orders magnitude smaller than that in fretting; (iii) the friction coefficient in nanofretting is much lower than that in fretting in slip regime; (iv) no obvious damage was observed after 50 cycles of nanofretting under a normal load of 10 mN.

Ontogeny of body size and shape of Antarctic and subantarctic fur seals

Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic (Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic (Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age

Comparison of the strain distribution obtained from multi scale and conventional approaches to modelling extrusion

An investigation of the application of a multi scale CAFE model to prediction of the strain localization phenomena in industrial processes, such as extrusion, is presented in this work. Extrusion involves the formation of a strong strain localization zone, which influences the final product microstructure and may lead to a coarse grain layer close to the surface. Modelling of the shape of this zone and prediction of the strain magnitude will allow computer aided design of the extrusion process and optimisation of the technological parameters with respect to the microstructure and properties of the products. Thus, the particular objective of this work is comparison of the FE and CAFE predictions of strain localization in the shear zone area in extrusion. Advantages and disadvantages of the developed CAFE model are also discussed on the basis of the simulation results.

A composite descriptor for shape retrieval

In this paper, a composite descriptor for shape retrieval has been proposed. The proposed descriptor is obtained from Generic Fourier Descriptors (GFD) for the shape region and the shape contour. A composite descriptor derived from GFD of the shape region and the shape contour is used for indexing and retrieval of shapes. Difference between two images is computed as the Euclidean distance between their composite descriptors. Experiments are performed to test the effectiveness of the proposed descriptor for retrieval of 2d images. Sets of composite descriptors, obtained by assigning different weights to the region component and the contour component, are also evaluated. Item S8 within the MPEG-7 Still Images Content Set is used for performing experiments; this dataset consists of 3621 still images. Experimental results show that the proposed descriptor is effective.

A cross-sectional study of weight-and shape-related beliefs, behaviours and concerns of north Queensland adolescents

The purpose of this study was to examine differences in weight- and shape-related beliefs, behaviours and concerns across a high school population. Data were collected by questionnaire from 902 high school students from private schools in Townsville. Concerns about weight and shape were more apparent in students from the higher school years. More girls in higher than lower school years were dissatisfied with their bodies, concerned that many parts of their bodies were too fat and more of them attempted weight loss. More boys in higher than lower school years were satisfied with their bodies but they wanted to 'bulk up'. Societal expectations of weight and shape may adversely affect both males and females but in different ways. Thus, interventions aiming to promote the maintenance of a healthy body weight may need to account for the desire of the majority of young women to be thinner, while the majority of young men would like to be larger.

Titanium–nickel shape memory alloy foams for bone tissue engineering

Titanium–nickel (TiNi) shape memory alloy (SMA) foams with an open-cell porous structure were fabricated by space-holder sintering process and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The mechanical properties and shape memory properties of the TiNi foam samples were investigated using compressive test. Results indicate that the plateau stresses and elastic moduli of the foams under compression decrease with the increase of their porosities. The plateau stresses and elastic moduli are measured to be from 1.9 to 38.3 MPa and from 30 to 860 MPa for the TiNi foam samples with porosities ranged from 71% to 87%, respectively. The mechanical properties of the TiNi alloy foams can be tailored to match those of bone. The TiNi alloy foams exhibit shape memory effect (SME), and it is found that the recoverable strain due to SME decreases with the increase of foam porosity.

The "other" in film : exclusions of Aboriginal indentity from Australian cinema

Throughout the latter half of the past century, cinema played a significant role in the shaping of the core narratives of Australia. Films express and implicitly shape national images and symbolic representations of cultural fictions in which ideas about Aboriginal identity have been embedded. In this article,1 exclusionary practices in Australian narratives are analyzed through examples of films representing Aboriginal identity. Through these filmic narratives the articulation, interrogation, and contestation of views about filmic representations of Aboriginal identity in Australia are illuminated. The various themes in the filmic narratives are examined in order to compare and contrast the ways in which Australian films display the operation of narrative closure and dualisms within the film texts.

Nursing and being nursed from patients' perspectives : an ethnographic study

The research was commenced to understand why patients submissively accept compliance in the nursing relationship. To understand this phenomenon, an anthropological perspective about nursing was sought through ethnographic processes, utilising The Ethnographic Research Cycle and The Developmental Research Sequence as detailed by James Spradley (1980). Ethnographic methods of fieldwork and participant observation were undertaken over a three month period in a district nursing service in a rural area of Victoria, Australia. There are three over arching aims. The first is to record information at risk of being lost, hence the ethnography is an archival record describing insiders' perspectives of nursing practice. Description brings into view broad contextual issues that shape nursing practice, the daily routines and cultural norms of nursing, whilst also giving voice to patients' experiences about being nursed. The early part of the thesis is descriptive of the mundanity of nursing practice and of being a patient as these interactions are of fundamental significance in giving meaning to people's lives. Secondly the inquiry seeks to capture the meaning patients attach to nursing. Further description continued to uncover perspectives of nursing that were layered to present an integrated whole that still acknowledges the integrity of individuals and structures that make up that whole. As the cultural picture gained detail, the expected norms of being a nurse and a patient became evident, revealing how culture gives shape to nursing and being nursed. Notions of time and space were found to be constructs of being a patient which shape the illness experience. They are not necessarily within a patient's control, nonetheless, there is a norm and deviation from this norm has consequences for patients. Thirdly, the ethnography conveys the expected behaviour for a person who becomes a patient, to make known the implicit meanings, norms of behaviour and unwritten rules that a patient needs to understand as they pass through various stages of the health care system. In conclusion, the ethnography consistently reveals the underlying conflict between what nurses believe they do and the meaning attached to the experience of being nursed. For example, some nurses practice with patients' values as central to practice; others believe they care, yet observation and patient conversations suggest that they do not. The ethnography revealed that society expects nurses to elicit and reinforce compliance. Similarly, the power of culture shapes the experience of patients as the desire to be accepted, as a personal need, and as a means of having their nursing needs met, means that patients will invariably be passively compliant. The consequence is that nurses have a dominant power differential over patients, therefore, if nursing is to continue to describe practice as humanistic and caring, they ought to actively seek to be aware of patients' values and be motivated to accept these as central to practice.

Do maternally derived antibodies and early immune experience shape the adult immune response?

1. Immunological imprinting by maternally derived antibodies has been proposed to have both positive and negative consequences for offspring immunity in early and adult life. However, few studies of maternal effects on immunity have followed individuals past the juvenile stages.

2. Using laboratory Japanese quail, we developed a novel method of directly manipulating yolk antibodies of neonates, and then followed individuals through a series of immune challenges until they were of reproductive age.

3. Our method of directly injecting purified antibodies into the yolk sac of newly hatched chicks successfully elevated the plasma titres of specific anti-KLH IgY in neonates. This allows us to test whether differences in neonatal anti-KLH IgY affect immunity at the juvenile and adult stages of life.

4. We found little evidence for an effect of maternal antibodies on juvenile stage immune response, in contrast to results from previous studies. Adult immune response depended largely on the magnitude of the juvenile immune response regardless of the identity of the antigen in the juvenile immune challenge, and did not depend on neonatal IgY titres. Our results are consistent with a priming effect of early immune experience on adult stage immune responsiveness, but we found no evidence of carryover effects of yolk-derived antibodies on adult immunity.

5. This study employs new methodology for investigation of maternal antibodies and presents results suggesting that further studies of maternal effects on immunity will require careful consideration of the numerous ways maternally derived yolk components can impact the different types of immune response.

Novel spectral descriptor for object shape

In this paper, we propose a novel descriptor for shapes. The proposed descriptor is obtained from 3D spherical harmonics. The inadequacy of 2D spherical harmonics is addressed and the method to obtain 3D spherical harmonics is described. 3D spherical harmonics requires construction of a 3D model which implicitly represents rich features of objects. Spherical harmonics are used to obtain descriptors from the 3D models. The performance of the proposed method is compared against the CSS approach which is the MPEG-7 descriptor for shape contour. MPEG-7 dataset of shape contours, namely, CE-1 is used to perform the experiments. It is shown that the proposed method is effective.

Need to know : lessons from Sino-Australian business negotiators on the importance of guanxi, emotions and generational differences in Chinese negotiation behaviour

The forces of globalisation over the last few decades have created opportunities for intemational business as never before, whilst leaving no organisation immune to competition. With the Global Financial Crisis impacting the world economy, the BRIC economies as a group - Brazil, Russia, India and China, have steadily benefited from continuing growth in 2008 and 2009 (Bhattacharya, Hemerling and Waltermann,2010). Despite China being a key international trading partner for Australia, the number of successful joint ventures and negotiations between the two countries remains limited. A closer examination of the international business interactions between Australia and China is thus urgently needed. When negotiating with the Chinese, Western managers may not always be aware of what they are really negotiating for. To be successful, they have to be equipped with the 'specialised knowledge', a form of 'tacit or implicit knowledge', which comes with experience (Nonaka, 1994, Pavesi, 2003) in communicating and negotiating with their Chinese counterparts. The Chinese way of business negotiation can challenge the logic of Western business thinking. This, coupled with possible generational differences or changes in the Chinese business counterpart's way of doing business, means we must try to understand the business communication and negotiation process from not only the Western but also the Chinese perspective. In particular, in addition to the contextual (Phatak, & Habib, 1996; Risberg, 1997), social (Ghauri, & Fang, 2001), and cognitive factors (George, Gareth, & Gonzalez, 1998) focused on by past researchers, the intangible aspects of negotiation must also be considered. These include trust, reputation, relationship quality (guanxi in the case of the Chinese), and the moods and emotions that shape the processes and outcomes of communication and negotiation (Griffith, 2002; Hartel & Ma, 2006; Ma & Hartel 2005; and Zhao & Krohmer, 2006). This paper reports on a qualitative investigation of the communication processes occurring in negotiations between Australian and Chinese managers and entrepreneurs. The examination is based on a theoretical framework looking at emotions and culture from an affective events theory (AET) perspective. Both interview and focus groups techniques were used. Findings identified guanxi, core to relationship development and maintenance in Chinese culture, together with emotions as major determining factors of negotiation outcomes. Findings also suggest there are generational differences in attitudes among Chinese managers with Gen. X and Gen. Y placing a different emphasis on guanxi in business. These findings suggest that the popular advice to people doing business in China is out of date.

Piecing together the puzzle of graduate employment : factors that shape the graduate work expectations of human resource management students

Providing graduates with a set of skills and attributes relevant to their future employment remains a key topic in both higher education policy and research. This paper reports findings from a pilot study of human resource management (HRM) students' perceptions of the graduate work experience. Specifically, it focuses on how these perceptions are shaped, driven by a concern for the uncertainty - and even fear - expressed by the study's participants in relation to their future workplace experiences. The influences of three key factors in shaping participants' expectations are discussed: the graduate recruitment experience, previous work experiences and 'graduate work folklore' from the stories of family and friends. With these influences not always providing students with a realistic picture of their future work experience, we conclude that educators need to improve the opportunities for practical experience and industry knowledge through work placements, stronger links with industry and increased exposure to the practicalities of work within the curriculum.

Reductions in nutrient discharge from aquaculture through recycling of water utilising floating media and activated carbon filtration

Nutrient discharge into coastal areas, such as the Great Barrier Reef can result in the degradation of coastal ecosystems. For example, excess nitrogen and phosphorus can damage corals through inducing algal bloom and subsequent shading. Excessive phosphorus can further weaken coral skeletons making them susceptible to damage. Land based industries such as aquaculture can contribute to such problems. This study set out to develop a system whereby water from aquaculture can be constantly reused resulting in minimized waste discharge. A three-stage filtration system utilizing floating media and activated carbon was designed to harness bacterial processes that could reduce both particulate and dissolved compounds to the extent whereby approximately 100% reuse of the wastewater became possible. This involved efficient and effective particulate and biological removal mechanisms in both aerobic and anaerobic zones of the filtration system. This design reduced dissolved nitrogen levels by up to 70% and maintained low phosphorus levels, which allowed the reuse of water for the successful culture of barramundi with a survival rate of 97% over 25 days. This pilot scale study demonstrated the potential of reusing aquaculture wastewater from the viewpoint of reducing nutrient input into coastal environments. Future research will refine these processes and assess the performance of the system at several commercial scale applications.