Phase equilibria study of pseudobrookite type minerals

Pseudobrookite, is found in volcanic rocks, and the mineral armalcolite ((Fe,Mg)Ti2O5) found in the Apollo 11 and subsequent lunar samples seems to be unique to the moon. In plutonic rocks on the earth, ilmenite and rutile were found with what appears to be an equilibrium liquidus texture, while on the moon armalcolite often appears to be the primary liquidus phase among Ti-oxides. This suggests that total pressure may be a factor in the formation of these minerals, and a knowledge of the phase relations in this system yields information about the pressure under which a given magma crystallized

Microprobe and oxygen fugacity study of armalcolite

The stability of synthetic armalcolite was determined as a function of oxygen fugacity with particular regard to the oxidation state of iron and titanium. The equilibrium pseudobrookite (armalcolite) composition was measured at 1200 C under various conditions of oxidation typical of the lunar environment. These data, when compared with published descriptions of mare basalts, provide information about the conditions of crystallization of armalcolite-bearing lunar rocks. Some information about the crystal chemistry of armalcolite was obtained from X-ray diffraction and electron microprobe analyses of synthetic armalcolite and Zr-armalcolite. Further data were gathered from a comparison of the Mossbauer spectra of a phase pure stoichiometric armalcolite and one containing appreciable amounts of trivalent titanium

Climate change adaptation: where does global health fit into the agenda?

The aim of this paper is to highlight the opportunities to improve health and reduce health inequities via the new and additional funding that is available for climate change adaptation activities.Human-induced climate change will affect the lives of most populations in the next decade and beyond. It will have greatest, and generally earliest, impact on the poorest and most disadvantaged populations on the planet. Changes in climatic conditions and increases in weather variability affect human wellbeing, safety, health and survival in many ways. Some impacts are direct-acting and immediate, such as impaired food yields and storm surges. Other health effects are less immediate and typically occur via more complex causal pathways that involve a range of underlying social conditions and sectors such as water and sanitation, agriculture and urban planning. Climate change adaptation is receiving much attention given the inevitability of climate change and its effects, particularly in developing contexts, where the effects of climate change will be experienced most strongly and the response mechanisms are weakest. Financial support towards adaptation activities from various actors including the World Bank, the European Union and the United Nations is increasing substantially. With this new global impetus and funding for adaptation action come challenges such as the importance of developing adaptation activities on a sound understanding of baseline community needs and vulnerabilities, and how these may alter with changes in climate. The global health community is paying heed to the strengthening focus on adaptation, albeit in a slow and unstructured manner.&nbsp

The Relationship between Within-Day Energy Balance and Menstruation in Active Females

Background: Past studies suggest that inadequate energy intake (EI) is directly related to menstrual dysfunction (MD) in active females. Inadequate EI causes activation of the hypothalamic-pituitary-adrenal axis, disrupting the normal hormonal signaling of reproductive cycling and resulting in MD. However, studies have also demonstrated similar EI in athletes, but with different menstrual function. Traditionally, energy balance has been evaluated in 24-hour time periods. Recent research suggests there is benefit to analyzing energy balance at smaller intervals to better address physiologic response in real time. It is possible that women who meet their daily EI needs could still, therefore, experience MD if the majority of the day is spent in energy deficit. Objective: The purpose of this study is to determine whether within-day energy balance is a factor in menstrual status in active adult females. Methods: Twenty active females tracked hourly EI and energy expenditure over three days. A two-page survey was utilized to obtain information on training, health, and menstrual status. Participants were also asked to respond to several questions regarding eating habits and attitude towards food. Within-day energy balance was calculated and evaluated using NutriTimingTM software. Collected energy balance data were analyzed for associations with menstrual status. Results: Participants spent more hours in a catabolic state (energy balance less than zero) than in an anabolic state (20.5 hrs vs 3.5 hrs) and averaged a caloric deficit of -504 kcal over 24-hours. Nine subjects (45%) had experienced loss of menses for greater than 3 months (LoM\u3e3mos), indicative of amenorrhea. Hours spent in energy surplus \u3e400 kcal was inversely correlated with LoM\u3e3mos (r = -0.463; P = 0.04). The impact of number of miles run per week and menstrual dysfunction, based on a quartile stratification of miles run, were analyzed using an ANOVA with Tamhane non-parametric post hoc test. Significant differences were found between the upper two quartiles of distance run per week and LoM\u3e3mos (P = 0.048). There was no relationship between end-of-day energy balance and Lom\u3e3mos. Conclusion: Researchers and healthcare professionals would do well to examine energy balance in an hour-by-hour manner as it is has implications for MD. This would help to clarify whether within-day energy balance is a factor in MD, and allow for the development of appropriate intervention strategies to improve health and athletic outcomes for active women

Investigating the effect of ultrasonic consolidation on shape memory alloy fibres

This research was driven by the capability of the Ultrasonic Consolidation (UC) manufacturing process to create smart metal matrix composites for use within high value engineering sectors, such as aerospace. The UC process is a hybrid additive/subtractive manufacturing process that embeds fibres into metal matrices via the exploitation of a high plastic flow, low temperature phenomenon encountered at ultrasonic frequency mechanical vibrations. The research concerned an investigation of the use of the UC process for embedding Nickel-Titanium alloy (NiTi) shape memory alloy (SMA) fibres into Aluminium (Al) matrices which could potentially be used as vibration damping structures, stress state variable structures, as well as other future smart material applications. It was hypothesised that the fibre volume fraction within a UC matrix was limited due to a reduction in foil/foil bonding, caused by increased fibre numbers, as opposed to the total level of plastic flow of the matrix material being insufficient to accommodate the increased fibre numbers. This hypothesis was tested by increasing the NiTi SMA fibre volume fraction, within an Al 3003 (T0) metal matrix, beyond that of previous UC work. The metal matrix and the fibre matrix interface of these samples was then microscopically analysed and the overall UC sample integrity was tested via mechanical peel testing. It was found that a fibre volume fraction of ~9.8% volume (30 X Ø100 µm SMA fibres) was the maximum achievable using an Al 3003 (T0) 100 µm thick foil material and conventional UC fibre embedding. A revised hypothesis was postulated that the interlaminar structure created during UC was affected by the process parameters used. This interlaminar structure contained areas of un-bonded foil and the increase of UC process parameters would reduce this area of un-bonded foil. Areas of this interlaminar structure were also thought to have undergone grain refinement which would have created harder material areas within the structure. It was suggested that maximum plastic flow of the matrix had not been reached and thus the use of larger diameter NiTi SMA fibres were embedded to increase the effective SMA fibre volume fraction within Al 3003 (T0) UC samples. It was suggested that the embedding of SMA fibres via UC had an abrasive effect on the SMA fibres and the SMA fibres had an effect on the Al 3003 (T0) microstructure. It was further suggested that the activation of UC embedded SMA fibres would reduce the strength of the fibre/matrix interface and the matrix would impede the ability of the SMA fibres to contract causing a forceful interaction at the fibre to matrix interface, weakening the UC structure. The investigation to test the revised hypothesis was broken down into three sections of study. Study 1 was a methodology to determine the characteristics of the interlaminar surface created via UC and how this surface affected the nature of the consolidated sample. UC samples of Al 3003 (T0) were manufactured using a range of process parameters. The analysis involved optical microscopy to determine the UC weld density and the interlaminar surface; mechanical peel testing to quantify the interlaminar bond strength; white light interferometry to measure the interlaminar surface profile and microhardness measurements to determine the hardness of the interlaminar material. Study 2 was a methodology to allow the analysis of the microstructural and mechanical interactions at the fibre/matrix interface, post-UC. Al 3003 (T0) samples were manufactured via UC using a range of process parameters with various NiTi SMA fibre diameters embedded. The analysis involved using mechanical peel testing to determine the interlaminar bond strength; optical microscopy to determine the level of fibre encapsulation; scanning electron microscopy and focussed ion beam analysis to analyse the fibre and matrix grain structures and microscopic interactions. Study 3 was a methodology to investigate the fibre usage as would be expected from envisaged applications of an SMA containing metal matrix composite. Samples were manufactured using a range of UC process parameters with various SMA fibre diameters embedded and the embedded SMA fibres were subjected to different extension/contraction cycle numbers. The analysis involved using mechanical peel testing to determine the interlaminar bond strength; optical microscopy to determine the level of fibre encapsulation and the interlaminar effect of fibre activation; fibre pullout testing to measurement the strength of the fibre/matrix interaction and load rate testing of the activated SMA fibres to monitor performance. The interlaminar surface was found to affect the strength and density of interlaminar bonding during the UC process and the use of higher UC process parameters affected this interlaminar structure. Levels of un-bonded material were found within the interlaminar structure and these levels were found to decrease with increasing sonotrode amplitude and pressure with reducing speed. It was suggested that a specifically texture sonotrode could be developed to modify the interlaminar structure to the requirements of the intended sample application. The measurement of the interlaminar material hardness was unsuccessful and future work would likely require a different methodology to measuring this. The work identified a grain refining effect of the embedded SMA fibres on the Al 3003 (T0) matrix material, (grain sizes were reduced from ~15 µm to <1 µm within 20 µm of the SMA fibres), as well as localised damage caused by the UC process to the SMA fibres. The performance of the activated SMA fibres established that this damage did not prohibit the ability of the SMAs to function however the compressive nature of the Al 3003 (T0) matrix was identified as reducing the ability of the SMA fibres to contract. Additionally it was found that the activation of SMA fibres within an Al 3003 (T0) matrix resulted in a reduction of the fibre/matrix interface strength which allowed fibres to be pulled from the composite with greater ease (a loss of ~80% was encountered after a single activation and extension cycle). The use of larger SMA fibre diameters allowed for the fibre volume fraction to be increased however the activation of these SMA fibres had a delaminating effect on the Al 3003 (T0) structure due to the size of the radial expansion of the SMA fibre. The work furthered the understanding of the effect of UC on SMA fibres and highlighted the importance of the interlaminar surface in UC and that to increase the SMA fibre volume fraction to a useable level (25-50%) then an alternative fibre embedding method within UC is required. The fibre/matrix interface interactions during SMA activation have implications in the ability of UC SMA embedded smart metal matrix composites to function successfully due to weakening effects on fibre matrix interface strength and the ability to achieve SMA fibre activation within the metal matrix

Climate change adaptation: where does global health fit in the agenda?

Human-induced climate change will affect the lives of most populations in the next decade and beyond. It will have greatest, and generally earliest, impact on the poorest and most disadvantaged populations on the planet. Changes in climatic conditions and increases in weather variability affect human wellbeing, safety, health and survival in many ways. Some impacts are direct-acting and immediate, such as impaired food yields and storm surges. Other health effects are less immediate and typically occur via more complex causal pathways that involve a range of underlying social conditions and sectors such as water and sanitation, agriculture and urban planning. Climate change adaptation is receiving much attention given the inevitability of climate change and its effects, particularly in developing contexts, where the effects of climate change will be experienced most strongly and the response mechanisms are weakest. Financial support towards adaptation activities from various actors including the World Bank, the European Union and the United Nations is increasing substantially. With this new global impetus and funding for adaptation action come challenges such as the importance of developing adaptation activities on a sound understanding of baseline community needs and ulnerabilities, and how these may alter with changes in climate. The global health community is paying heed to the strengthening focus on adaptation, albeit in a slow and unstructured manner. The aim of this paper is to provide an overview of adaptation and its relevance to global health, and highlight the opportunities to improve health and reduce health inequities via the new and additional funding that is available for climate change adaptation activities

Noisy Monte Carlo: Convergence of Markov chains with approximate transition kernels

Monte Carlo algorithms often aim to draw from a distribution $\pi$ by simulating a Markov chain with transition kernel $P$ such that $\pi$ is invariant under $P$. However, there are many situations for which it is impractical or impossible to draw from the transition kernel $P$. For instance, this is the case with massive datasets, where is it prohibitively expensive to calculate the likelihood and is also the case for intractable likelihood models arising from, for example, Gibbs random fields, such as those found in spatial statistics and network analysis. A natural approach in these cases is to replace $P$ by an approximation $\hat{P}$. Using theory from the stability of Markov chains we explore a variety of situations where it is possible to quantify how 'close' the chain given by the transition kernel $\hat{P}$ is to the chain given by $P$. We apply these results to several examples from spatial statistics and network analysis.Comment: This version: results extended to non-uniformly ergodic Markov chain