The optimization and comparison of a cerium salt-based phosphate filtration system to industry standard phosphate removal water filtration systems

Phosphorous, being one of the fundamental building blocks of life, has been linked with the increase of cyanobacteria and algae growth. One of the main ways that phosphorous enters the marine ecosystem is through the form of runoff phosphates from fertilizers and industrial processes. In addition to disrupting the biology of ecosystems another drawback of excess of phosphates is the tendency for these chemical groups to form scale buildup on metal through the form of calcium phosphate. The goal of our project is to investigate a novel way of removing phosphate groups from wastewater with the use of the rare earth element cerium. Current methods that remove phosphates use iron and aluminum salts to react with the phosphate, creating crystalline complexes that can be filtered out as a precipitate. Our team hopes to evaluate a similar precipitation reaction with phosphate and cerium and evaluate the optimal parameter that promote the desired reaction. The main benefit of this reaction is that its crystals are exponentially smaller than the ones produced by the traditional phosphate removal processes (indicating that this novel method might be more efficient than the traditional methods). The main challenge of this project is to properly characterize the produced cerium phosphate crystals and design an industry-scale filtration process that would remove these crystals effectively. This analysis will be completed with the use of analytical chemistry techniques, nano-characterization equipment and process engineering design work. The filtration system design process will focus on optimizing produced crystalline complexes and then collecting and removing them effectively for large quantities of water. This project is being conducted with the support of ChemTreat, and with this partnership we hope to compare this new cerium based phosphate removal method with the current ferric-aluminum based methods. The results of this comparison could lead to the development of an entirely new and more effective method of removing phosphate from wastewater.https://scholarscompass.vcu.edu/capstone/1012/thumbnail.jp

Exploring AGN Activity over Cosmic Time with the SKA

In this Chapter we present the motivation for undertaking both a wide and deep survey with the SKA in the context of studying AGN activity across cosmic time. With an rms down to 1 $\mu$Jy/beam at 1 GHz over 1,000 - 5,000 deg$^2$ in 1 year (wide tier band 1/2) and an rms down to 200 nJy/beam over 10 - 30 deg$^2$ in 2000 hours (deep tier band 1/2), these surveys will directly detect faint radio-loud and radio-quiet AGN (down to a 1 GHz radio luminosity of about $2\times10^{23}$ W/Hz at $z=6$). For the first time, this will enable us to conduct detailed studies of the cosmic evolution of radio AGN activity to the cosmic dawn ($z\gtrsim6$), covering all environmental densities.Comment: 17 pages, 7 figures, to appear as part of 'Continuum Science' in Proceedings 'Advancing Astrophysics with the SKA (AASKA14)

Investigating predictive coding in younger and older children using MEG and a multi-feature auditory oddball paradigm

There is mounting evidence for predictive coding theory from computational, neuroimaging, and psychological research. However, there remains a lack of research exploring how predictive brain function develops across childhood. To address this gap, we used pediatric magnetoencephalography to record the evoked magnetic fields of 18 younger children (M = 4.1 years) and 19 older children (M = 6.2 years) as they listened to a 12-min auditory oddball paradigm. For each child, we computed a mismatch field "MMF": an electrophysiological component that is widely interpreted as a neural signature of predictive coding. At the sensor level, the older children showed significantly larger MMF amplitudes relative to the younger children. At the source level, the older children showed a significantly larger MMF amplitude in the right inferior frontal gyrus relative to the younger children, P < 0.05. No differences were found in 2 other key regions (right primary auditory cortex and right superior temporal gyrus) thought to be involved in mismatch generation. These findings support the idea that predictive brain function develops during childhood, with increasing involvement of the frontal cortex in response to prediction errors. These findings contribute to a deeper understanding of the brain function underpinning child cognitive development

Fast Radio Burst Tomography of the Unseen Universe

The discovery of Fast Radio Bursts (FRBs) at cosmological distances has opened a powerful window on otherwise unseen matter in the Universe. In the 2020s, observations of $>10^{4}$ FRBs will assess the baryon contents and physical conditions in the hot/diffuse circumgalactic, intracluster, and intergalactic medium, and test extant compact-object dark matter models.Comment: Science white paper submitted to the Astro2020 Decadal Survey. 15 pages, 3 color figure

Low frequency radio continuum imaging and SED modeling of 11 LIRGs: radio-only and FUV to radio bands

We present the detailed analysis of 11 local luminous infrared galaxies (LIRGs) from ultraviolet through far-infrared to radio ($\sim$70 MHz to $\sim$15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observations at 325 and 610 MHz from the GMRT and the measurements from public archives. Our main results are (1) radio SEDs show turnovers and bends, (2) the synchrotron spectral index of the fitted radio spectra ranges between $-$0.5 and $-$1.7, and (3) the infrared luminosity, dust mass, dust temperature, stellar mass, star-formation rates (SFRs) and AGN fraction obtained from CIGALE falls in the range exhibited by galaxies of the same class. The ratio of 60$\mu$m infrared and 1.4 GHz radio luminosity, the 1.4 GHz thermal fraction, and emission measure range between 2.1 and 2.9, 0.1% and 10%, 0.02 and 269.5$\times$10$^{6}$ cm$^{-6}$ pc, respectively. We conclude that the turnovers seen in the radio SEDs are due to free-free absorption; this is supported by the low AGN fraction derived from the CIGALE analysis. The decomposed 1.4 GHz thermal and nonthermal radio luminosities allowed us to compute the star formation rate (SFR) using scaling relations. A positive correlation is observed between the SFR$_{IR}$ obtained 10 Myr ago (compared to 100 Myr ago) and 1.4 GHz radio (total and nonthermal) because similar synchrotron lifetimes are expected for typical magnetic field strengths observed in these galaxies ($\approx$50$\mu$G).Comment: ApJ accepted. Comments are welcom

Low-frequency radio continuum imaging and SED modeling of 11 LIRGs : radio-only and FUV to radio bands

We present a detailed analysis of 11 local luminous infrared galaxies from ultraviolet through far-infrared to radio (∼70 MHz to ∼15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observations at 325 and 610 MHz from the GMRT and the measurements from public archives. Our main results are (1) radio SEDs show turnovers and bends, (2) the synchrotron spectral index of the fitted radio spectra ranges between −0.5 and −1.7, and (3) the infrared luminosity, dust mass, dust temperature, stellar mass, star formation rates (SFRs), and active galactic nuclei (AGN) fraction obtained from CIGALE fall within the range exhibited by galaxies of the same class. The ratio of 60 μm infrared and 1.4 GHz radio luminosity, the 1.4 GHz thermal fraction, and emission measure range between 2.1 and 2.9, 0.1% and 10%, 0.02 and 269.5 $\times$ 10$^{6}$ cm$^{-6}$ pc, respectively. We conclude that the turnovers seen in the radio SEDs are due to free–free absorption; this is supported by the low AGN fraction derived from the CIGALE analysis. The decomposed 1.4 GHz thermal and nonthermal radio luminosities allowed us to compute the SFR using scaling relations. A positive correlation is observed between the SFR$_{IR}$ obtained 10 Myr ago (compared to 100 Myr ago) and 1.4 GHz radio (total and nonthermal) because similar synchrotron lifetimes are expected for typical magnetic field strengths observed in these galaxies (≈50 μG)

Astronomy below the survey threshold in the SKA era

Astronomy at or below the 'survey threshold' has expanded significantly since the publication of the original 'Science with the Square Kilometer Array' in 1999 and its update in 2004. The techniques in this regime may be broadly (but far from exclusively) defined as 'confusion' or 'P(D)' analyses (analyses of one-point statistics), and 'stacking', accounting for the flux-density distribution of noise-limited images co-added at the positions of objects detected/isolated in a different waveband. Here we discuss the relevant issues, present some examples of recent analyses, and consider some of the consequences for the design and use of surveys with the SKA and its pathfinders

The Men's Safer Sex (MenSS) trial: protocol for a pilot randomised controlled trial of an interactive digital intervention to increase condom use in men

Sexually transmitted infections (STI) are a major public health problem. Condoms provide effective protection but there are many barriers to use. Face-to-face health promotion interventions are resource-intensive and show mixed results. Interactive digital interventions may provide a suitable alternative, allowing private access to personally tailored behaviour change support. We have developed an interactive digital intervention (the Men's Safer Sex (MenSS) website) which aims to increase condom use in men. We describe the protocol for a pilot trial to assess the feasibility of a full-scale randomised controlled trial of the MenSS website in addition to usual sexual health clinical care

The Lobby in transition: what the 2009 MPs’ expenses scandal revealed about the changing relationship between politicians and the Westminster Lobby?

The 2009 MPs' expenses scandal was one of the most significant political stories of modern times. It raised questions, not just about the ethics and behaviour of MPs but also about the relationship between politicians at Westminster and the political correspondents who follow them on a daily basis, known as ‘the lobby’. For the significance of this scandal, in media terms, was that the story was not broken by members of the lobby but came from outside the traditional Westminster news gathering process. This paper examines why this was the case and it compares the lobby today with that which was described and analysed by Jeremy Tunstall and Colin Seymour-Ure in their respective studies more than 40 years ago. The article concludes that the lobby missed the story partly because of the nature of the lobby itself and partly as a result of a number of specific changes which have taken place in the media and the political systems over the past 40 years