Machining of titanium alloy (Ti-6Al-4V)-theory to application

This article correlates laboratory-based understanding in machining of titanium alloys with the industry based outputs and finds possible solutions to improve machining efficiency of titanium alloy Ti-6Al-4V. The machining outputs are explained based on different aspects of chip formation mechanism and practical issues faced by industries during titanium machining. This study also analyzed and linked the methods that effectively improve the machinability of titanium alloys. It is found that the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts. These challenges are correlated and affected by each other. Sawtooth chips cause variation in cutting forces which results in high cyclic stress on cutting tools. On the other hand, low thermal conductivity of titanium alloy causes high temperature. These cause a favorable environment for high tool wear. Thus, improvements in machining titanium alloy depend mainly on overcoming the complexities associated with the inherent properties of this alloy. Vibration analysis kit, high pressure coolant, cryogenic cooling, thermally enhanced machining, hybrid machining and, use of high conductive cutting tool and tool holders improve the machinability of titanium alloy.

Machinability assessment and surface integrity characteristics of Austempered Ductile Iron (ADI) using ultra-hard cutting tools

The application of austempered ductile iron (ADI) is gaining an ever greater share of the worldwide ferrous product market, specifically centering on the aerospace, automotive and shipping industries. ADI is a heat treated cast iron, which exhibits remarkable mechanical properties and provides an attractive material for designers and engineers to displace conventional materials. Previous attempts, however, to machine ADI using carbide or ceramic cutting tools produced poor tool life characteristics due to the relatively poor machinability of the workpiece. This paper presents a research study that has applied the advanced technology of modern ultrahard cutting tools, in an attempt to achieve enhanced machinability performance. This performance was evaluated through the analysis of cutting forces, tool wear, surface finish and roundness.

Wear characteristics of ultra-hard cutting tools when machining austempered ductile iron

Nodularised Ductile Cast Iron, when subjected to heat treatment processes - austenitising and austempering produces Austempered Ductile Iron (ADI). The microstructure of ADI also known as "ausferrite" consists of ferrite, austenite and graphite nodules. Machining ADI using conventional techniques is often a problematic issue due to the microstructural phase transformation from austenite to martensite during machining. This paper evaluates the wear characteristics of ultra hard cutting tools when machining ADI and its effect on machinability. Machining trials consist of turning ADI (ASTMGrade3) using two sets of PCBN tools with 90% and 50% CBN content and two sets of ceramics tools; Aluminium Oxide Titanium Carbide and Silicon Carbide - whisker reinforced Ceramic. The cutting parameters chosen are categorized as roughing and finishing conditions; the roughing condition comprises of constant cutting speed (425 m/min) and depth of cut (2mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The finishing condition comprises of constant cutting speed (700 m/min) and depth of cut (0.5mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The benchmark condition to evaluate the performance of the cutting tools was tool wear evaluation, surface texture analysis and cutting force analysis. The paper analyses thermal softening of the workpiece by the tool and its effect on the shearing mechanism under rough and finish machining conditions in term of lower cutting forces and enhanced surface texture of the machined part.

The clinical application of three screening tools for recognizing post-partum depression

Postnatal depression is a major health issue for childbearing women world-wide, as it is not always identified early. This study aimed to evaluate the clinical application of three screening instruments for the early recognition of post-partum depression, the Postpartum Depression Prediction Inventory, the Postpartum Depression Screening Scale and the Edinburgh Postnatal Depression Scale, and to examine nurse interventions following use of the instruments. Data were collected at two points, at 28 weeks prenatal (107 women) and eight weeks postnatal (84 women). Results showed that 17% of the women scored significant symptoms of post-partum depression and 10–15% had a positive screen for major postnatal depression. There was a statistically significant correlation between the total score on the Postpartum Depression Screening Scale and the Edinburgh Postnatal Depression Scale. Of those eight women identified as being at risk, seven had received anticipatory guidance and five had received counselling by the nurses. The Postpartum Depression Prediction Inventory enabled nurses to identify women at risk of post-partum depression and offer interventions.

A comparison of search functions and other navigational tools provided on government websites

This paper reports the outcomes of a study that evaluated the effectiveness of search functions compared to other navigational tools available on government websites. The study used an observation exercise triangulated with a post observation interview. Results suggest that while there wasn't any significant difference in effectiveness between search functions and other navigational tools, the skill with which the search function is implemented and participants' familiarity with the website, are fundamental determinants of users' opinions. Implications of the findings for research and practice are discussed.

Stress analysis of compression of aluminium with rotating tools

Compression tests carried out on aluminium specimens showed that when the die was rotated the compression load dropped. A slab method is employed to examine this process. The load reduction is explained by the deviation of friction vector due to the relative circumferential movement between the die and the material. This mechanism is incorporated into a theoretical model and an expression is derived for compression pressure. Analytical solutions established compare favourably with experimental results. It is also shown that there is a limitation to the load reduction: the compressive load can never be lower than 70 percent of the yield limit.

Ecologically sustainable development and architecture: the impact of rating tools

The concept of Ecologically Sustainable Development (ESD) has become an important issue – albeit often scarcely applied – in the design of commercial buildings. To encourage the adoption of sustainable strategies in the practice of design and to address the environmental problems caused by these developments, governments and organisations of various countries have proposed the adoption of scorecard rating tools to inform designers of the impact of their decisions and to present a way of establishing project goals and objectives early in the design process. In Australia, the recent introduction of the Green Star Rating Tool (Office Design) is believed to provide the architects with a ‘whole-of-building’ assessment of the environmental impact of their design by creating a checklist against which to benchmark performance. This paper follows the design of a commercial building, evaluating the impact of Green Star in the overall process. The results of the study suggest the need to include the use of scorecard rating tools in a more integrated model, where ESD is considered at every stage of design and construction rather than being a separate component applied only to promote the ‘greenness’ of a building. Rating tools can be an asset to the design team, provided sustainable requirements are reinforced throughout the entire process.

A lower bound on effective performance testing for digital forensic tools

The increasing complexity and number of digital forensic tasks required in criminal investigations demand the development of an effective and efficient testing methodology, enabling tools of similar functionalities to be compared based on their performance. Assuming that the tool tester is familiar with the underlying testing platform and has the ability to use the tools correctly, we provide a numerical solution for the lower bound on the number of testing cases needed to determine comparative capabilities of any set of digital forensic tools. We also present a case study on the performance testing of password cracking tools, which allows us to confirm that the lower bound on the number of testing runs needed is closely related to the row size of certain orthogonal arrays. We show how to reduce the number of test runs by using knowledge of the underlying system

An effective and efficient testing methodology for correctness testing for file recovery tools

We hereby develop an effective and efficient testing methodology for correctness testing for file recovery tools across different file systems. We assume that the tool tester is familiar with the formats of common file types and has the ability to use the tools correctly. Our methodology first derives a testing plan to minimize the number of runs required to identify the differences in tools with respect to correctness. We also present a case study on correctness testing for file carving tools, which allows us to confirm that the number of necessary testing runs is bounded and our results are statistically sound.

Trialing new assessment tools to identify women at risk of PND

Objectives: The objectives of this study were to trial the Postpartum Depression Predictors Inventory (PDPI) as a checklist to assist nurses in identifying women at risk of postnatal depression at 28 weeks of pregnancy, with repeated assessment at 6-8 weeks postpartum.

Methods: A prospective cohort design was used to include a population of women >20 years of age who were attending an antenatal clinic at a Victorian regional hospital. All women who attended the clinic for their 28 week visit were invited to participate over an 8-week period. Five data collection measures were included, two in the antenatal period and three at 6-8 weeks postpartum. Based on nurse consultation at both times, clinical judgement, and use of the PDPI, nurses recorded three outcomes: no identifiable risk, non-directive counselling or referral to a psychiatric nurse. The Postpartum Depression Screening Scale (PDSS), Edinburgh Postnatal Depression Scale (EPDS) and Kanzas Marital Satisfaction Scales were used at 6-8 weeks postpartum to assess depression and marital satisfaction.

Results: 107 women were recruited in the antenatal period with 84 being followed up 8 weeks postpartum. Information will be presented on the proportion of women who were found to be depressed at both data collection periods, the intervention outcomes as determined by nurses. The use of the PDPI and PDSS as tools to assist nurses in identifying women at risk of postnatal depression will be discussed.

Conclusion: The PDPI is a useful checklist to identify women at risk of postnatal depression. The PDSS and the EPDS identified a similar number of women, although the PDSS is a much longer and more intensive scale.