Fabrication of micro-scale features on titanium alloys through micromilling.

Structured surfaces are of high interest in the manufacturing world, allowing for functionality to be applied to materials through nothing more than a change in the surface topography or an application of a surface coating. Applications for these surfaces range greatly, including, optical surfaces for antireflective surfaces, thermal structures to assist in heat dispersion and anti-fouling surfaces to reduce organisms from adhering to components. Hydrophobic structures, such as the one that have been examined on the lotus leaf under SEM, generate high droplet contact angles and roll off. The manipulation of surface wettability is of particular interest in areas such as the medical sector for self-cleaning applications or controlling cell adhesion on the surface of an implant. This work investigates the generation of micron level hydrophobic features on two Titanium alloys, Ti-6Al-4V alpha-beta alloy and Ti-30Nb beta alloy, with the aim of identifying how accurately surface structures can be produced through micromilling as well as experimentally testing how successfully these surfaces function after being fabricated. On each alloy, nine different 5mm x 5mm test pillars are machined using micromilling, half of each pillar is machined with 200μm wide and 30μm deep channels, generating a hydrophobic groove structure, and the other half being flat machined. Across these nine pillars the feedrate, spindle speed, axial depth of cut and tool step over were varied to optimise these parameters in terms of structure generation, channel bottom surface roughness and tool to workpiece interaction in an attempt to determine how effective micromilling is as at structuring the surface of beta Titanium alloys. Tool condition was assessed qualitatively using SEM imaging and an independent assessment was carried out to determine the mechanical properties of the beta Titanium alloy being machined.MSc by Research in Manufacturin

Mind the gap(s)…in theory, method and data: Re-examining Kanazawa (2006)

Kanazawa (2006) has put forward an evolutionarily grounded theory which claims that ‘individuals in wealthier and more egalitarian societies live longer and stay healthier not because they are wealthier or more egalitarian but because they are more intelligent’ (2006: 637). The claim rests on an argument which asserts that general intelligence is a solution to evolutionarily novel problems and that most dangers to health in contemporary society are evolutionarily novel. Kanazawa also claims that this relationship does not hold in sub-Saharan Africa. These claims are based on a cross-national analysis which finds a positive correlation between ‘national’ IQ scores and mortality data. The implication is that intelligence is the principal factor determining longevity in the rest of the world, regardless of issues such as adequacy of diet and availability of health care. Kanazawa’s theoretical claims about the evolution of general intelligence as a domain-specific adaptation are inconsistent with adaptationist analysis: natural selection does not solve general problems. The assumptions that sub-Saharan Africa is more representative of the evolutionary past than is the rest of the world, and that most hazards to health in contemporary society are evolutionarily novel, are implausible. The methods used are inadequate because Kanazawa argues for causation from correlation and fails to consider alternative explanations. The IQ data are flawed for reasons to do with sample size and sampling, extrapolation, and inconsistency across measures. Nor are they temporally compatible with the economic and demographic data

Fabrication of functionalised surfaces on gum metal (Ti-30Nb) using micromachining

Structured surfaces are attracting deep interest, as they allow tailoring the functionality via changes in the surface topography. Applications for these surfaces range greatly, including, optical surfaces for antireflective surfaces, thermal structures to assist in heat dispersion and anti-fouling surfaces to reduce micro-organisms from adhering to components. Gum metal is a relatively newer kind of beta titanium alloy that has earmarked its place as the next generation Ortheopedic implant material. In a timely effort, this work investigated the generation of micron level structured surfaces on Gum metal (Ti-30Nb – a beta titanium alloy) to explore micromilling as the robust scalable process to achieve low dimensional surfaces in titanium alloy. During micromilling, the feedrate, spindle speed, axial depth of cut and tool step over were varied to optimise these parameters for achieving superior quality of machining

Multi-view fringe projection system for surface topography measurement during metal powder bed fusion

Metal powder bed fusion (PBF) methods need in-process measurement methods to increase user confidence and encourage further adoption in high-value manufacturing sectors. In this paper, a novel measurement method for PBF systems is proposed that uses multi-view fringe projection to acquire high-resolution surface topography information of the powder bed. Measurements were made using a mock-up of a commercial PBF system to assess the system’s accuracy and precision in comparison to conventional single-view fringe projection techniques for the same application. Results show that the multi-view system is more accurate, but less precise, than single view fringe projection on a point-by-point basis. The multi-view system also achieves a high degree of surface coverage by using alternate views to access areas not measured by a single camera

Impact of deforestation on habitat connectivity thresholds for large carnivores in tropical forests

Introduction Deforestation significantly impacts large carnivores that depend on large tracts of interconnected forest habitat and that are sensitive to human activities. Understanding the relationship between habitat use and spatial distribution of such species across human modified landscapes is critical when planning effective conservation strategies. This study assessed the presence of potential landscape connectivity thresholds resulting from habitat fragmentation associated with different deforestation patterns using a scale-based approach that links species-specific home ranges with the extent of anthropogenic activities. The objectives were (1) to quantify the spatial and temporal distribution of natural vegetation for five common deforestation patterns and (2) to evaluate the connectivity associated with these patterns and the existence of potential thresholds affecting jaguar dispersal. The Bolivian lowlands, located within jaguar conservation units, were analysed with landscape metrics to capture the spatial and temporal changes within deforested areas and to determine potential impact on jaguar connectivity and connectivity thresholds for dispersal. Results Over the period of 1976–2005, the amount of natural vegetation has decreased by more than 40% in all locations with the biggest changes occurring between 1991 and 2000. Landscape spatial structure around jaguar locations showed that jaguars used areas with mean proportion of natural areas = 83.14% (SE = 3.72%), mean patch density = 1.16 patches/100 ha (SE = 0.28 patches/100 ha), mean patch area = 616.95 ha (SE = 172.89 ha) and mean edge density = 705.27 m/ha (SE = 182.19 m/ha).We observed strong fragmentation processes in all study locations, which has resulted in the connectivity of jaguar habitat decreasing to <20% by 2005. A connectivity threshold zone was observed when the proportion of natural vegetation was less than 58.4% (SE = 1.3). Conclusions Assessing fragmentation and connectivity for carnivores within the extent of human-modified landscapes proved to be an effective way to understand the changes caused by deforestation and their potential effects on large carnivore habitats. Our study highlights the importance of scale-based approaches for assessing current conservation challenges to protect large carnivores

Mental health in UK Biobank: development, implementation and results from an online questionnaire completed by 157 366 participants

Background UK Biobank is a well-characterised cohort of over 500 000 participants that offers unique opportunities to investigate multiple diseases and risk factors. Aims An online mental health questionnaire completed by UK Biobank participants was expected to expand the potential for research into mental disorders. Method An expert working group designed the questionnaire, using established measures where possible, and consulting with a patient group regarding acceptability. Case definitions were defined using operational criteria for lifetime depression, mania, anxiety disorder, psychotic-like experiences and self-harm, as well as current post-traumatic stress and alcohol use disorders. Results 157 366 completed online questionnaires were available by August 2017. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status than the general population across a range of indicators. Thirty-five per cent (55 750) of participants had at least one defined syndrome, of which lifetime depression was the most common at 24% (37 434). There was extensive comorbidity among the syndromes. Mental disorders were associated with high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation. Conclusions The questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed owing to selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health

Australian clinical practice guidelines for the diagnosis and management of Barrett's esophagus and early esophageal adenocarcinoma

Author version made available following 12 month embargo from date of publication according to publisher copyright policy.Barrett's esophagus (BE), a common condition, is the only known precursor to esophageal adenocarcinoma (EAC). There is uncertainty about the best way to manage BE as most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Moreover, there have been recent advances in knowledge and practice about the management of BE and early EAC. To aid clinical decision making in this rapidly moving field, Cancer Council Australia convened an expert working party to identify pertinent clinical questions. The questions covered a wide range of topics including endoscopic and histological definitions of BE and early EAC; prevalence, incidence, natural history, and risk factors for BE; and methods for managing BE and early EAC. The latter considered modification of lifestyle factors; screening and surveillance strategies; and medical, endoscopic, and surgical interventions. To answer each question, the working party systematically reviewed the literature and developed a set of recommendations through consensus. Evidence underpinning each recommendation was rated according to quality and applicability