Variations in mid-ocean ridge CO2 emissions driven by glacial cycles

The geological record shows links between glacial cycles and volcanic productivity, both subaerially and at mid-ocean ridges. Sea-level-driven pressure changes could also affect chemical properties of mid-ocean ridge volcanism. We consider how changing sea-level could alter the CO2 emissions rate from mid-ocean ridges, on both the segment and global scale. We develop a simplified transport model for a highly incompatible element through a homogenous mantle; variations in the melt concentration the emission rate of the element are created by changes in the depth of first silicate melting. The model predicts an average global mid-ocean ridge CO2 emissions-rate of 53 Mt/yr, in line with other estimates. We show that falling sea level would cause an increase in ridge CO2 emissions with a lag of about 100 kyrs after the causative sea level change. The lag and amplitude of the response are sensitive to mantle permeability and plate spreading rate. For a reconstructed sea-level time series of the past million years, we predict variations of up to 12% (7 Mt/yr) in global mid-ocean ridge CO2 emissions. The magnitude and timing of the predicted variations in CO2 emissions suggests a potential role for ridge carbon emissions in glacial cycles

Flight velocity effects on jet noise of several variations of a twelve-chute suppressor installed on a plug nozzle

Because of the relatively high takeoff speeds of supersonic transport aircraft, it is important to know whether the flight velocity effects the noise level of suppressor nozzles. To investigate this, a modified F-106B aircraft was used to conduct a series of flyover and static tests on a 12-chute suppressor installed on an uncooled plug nozzle. Comparison of flyover and static spectra indicated that flight velocity adversely affected noise suppressions of the 12-chute configurations

Isolated testing of highly maneuverable inlet con cepts

Ten percent scale models of a Mach 2.2 two dimensional inlet and a Mach 2.0 axisymmetric inlet were tested in the NASA Lewis Research Center 8'x6' Supersonic Wind Tunnel as part of a cooperative effort with the McDonnell Aircraft Company. The objective of this effort was to test methods designed to increase the maneuvering performance of fighter aircraft inlets. Maneuvering improvement concepts were tested up to 40-deg angle of attack for Mach numbers of 0.6 and 0.9, and up to 25 deg for Mach numbers 1.2 and 1.4. Maneuvering improvement concepts included a rotating cowl lip, auxiliary inlets aft of the inlet throat, and a retracting centerbody for the axisymmetric inlet. Test results show that the rotating cowl design was effective in improving subsonic maneuvering performance for both inlets. Auxiliary inlets did not produce significant performance increases for either model. The retracted centerbody resulted in some performance benefits at high angles of attack. None of the maneuvering improvement concepts were effective at Mach 1.2 and 1.4

Embodied innovation and regulation of medical technoscience: transformations in cancer patienthood

Biomedical advances are transforming the diagnosis and treatment of disease. Patienthood is also transforming, as patients actively participate in research, innovation and regulation of novel technologies and therapies. In this paper we explore the new kinds of practices that patients are performing in their roles as research subject, co-researchers, donors, campaigners, representatives and consumers of novel stratified therapies. We outline their embodied contributions to clinical trials, biobanks and stratified therapies prior to, during and after having cancer. Exploring how patienthood involves donating more than tissue or data to these developments, we consider their emotional and identity work which informs and shapes the novel diagnostics and therapies being developed. We also consider how this kind of work is stratified according to the social and biological location of participants, and end by reflecting on the implications of our analysis for the organisation and regulation of biomedicine

A Detailed Study of Giants and Horizontal Branch Stars in M68: Atmospheric Parameters and Chemical Abundances

In this paper, we present a detailed high-resolution spectroscopic study of post main sequence stars in the Globular Cluster M68. Our sample, which covers a range of 4000 K in $T_{eff}$, and 3.5 dex in $log(g)$, is comprised of members from the red giant, red horizontal, and blue horizontal branch, making this the first high-resolution globular cluster study covering such a large evolutionary and parameter space. Initially, atmospheric parameters were determined using photometric as well as spectroscopic methods, both of which resulted in unphysical and unexpected $T_{eff}$, $log(g)$, $\xi_{t}$, and [Fe/H] combinations. We therefore developed a hybrid approach that addresses most of these problems, and yields atmospheric parameters that agree well with other measurements in the literature. Furthermore, our derived stellar metallicities are consistent across all evolutionary stages, with $\langle$[Fe/H]$\rangle$ = $-$2.42 ($\sigma$ = 0.14) from 25 stars. Chemical abundances obtained using our methodology also agree with previous studies and bear all the hallmarks of globular clusters, such as a Na-O anti-correlation, constant Ca abundances, and mild $r$-process enrichment.Comment: Accepted to the Astronomical Journa

A Decision Support Model Using Life Cycle Cost (LCC) Analysis to Select Cost-Effective Alternatives for Hazardous Materials

This research focuses on the development of a decision support model to select cost-effective alternatives for hazardous materials using life cycle cost (LCC) analysis. The model provides an effective decision-making tool to evaluate the economic feasibility of using alternatives for hazardous materials. Given a specific operation, the users of this model can enter site-specific cost data to determine the total LCCs of using baseline hazardous materials (i.e., hazardous materials currently being used in an operation), as well as the total LCCs of using various alternatives. This thesis postulates that the material having the lowest total LCC is considered to be the best alternative. In calculating the total LCC of a material, the following 12 LCC categories are evaluated: procurement, transportation, handling, facility, personal protection, medical, training, emergency response, monitoring, disposal, liability, and intangible cost. This research also includes a case study of an Air Force operation (Pathology Lab Tissue Processing) to illustrate the use of the decision support model. Although the case study specifically addresses a single Air Force operation, the model can be applied to any operation that uses hazardous materials

Higher physical fitness levels are associated with less language decline in healthy ageing

Healthy ageing is associated with decline in cognitive abilities such as language. Aerobic fitness has been shown to ameliorate decline in some cognitive domains, but the potential benefits for language have not been examined. In a cross-sectional sample, we investigated the relationship between aerobic fitness and tip-of-the-tongue states. These are among the most frequent cognitive failures in healthy older adults and occur when a speaker knows a word but is unable to produce it. We found that healthy older adults indeed experience more tip-of-the-tongue states than young adults. Importantly, higher aerobic fitness levels decrease the probability of experiencing tip-of-the-tongue states in healthy older adults. Fitness-related differences in word finding abilities are observed over and above effects of age. This is the first demonstration of a link between aerobic fitness and language functioning in healthy older adults