Supersymmetric D3/D5 for massive defects on curved space

We construct the holographic dual for $\mathcal N=4$ SYM on $\rm S^4$ and $\rm AdS_4$ coupled to massive $\mathcal N=2$ supersymmetric quenched flavor fields on a codimension-1 defect, which is $\rm S^3$ and $\rm AdS_3$, respectively. The holographic description is in terms of a D3/probe D5 brane system. We set up and reduce the BPS equations for D5-brane embeddings with arbitrary supersymmetric deformations and partly solve them at the non-linear level. The remaining equations are solved explicitly in a small-mass expansion. We compute the contribution of the defect fields to the partition function on S$^4$ and compare to a field theory computation using supersymmetric localization, for which we set up the matrix model. Both computations agree, lending strong support to holographic probe brane constructions using D3/D5 configurations in general.Comment: 34 pages, 1 figur

Supersymmetric D3/D7 for holographic flavors on curved space

We derive a new class of supersymmetric D3/D7 brane configurations, which allow to holographically describe N=4 SYM coupled to massive N=2 flavor degrees of freedom on spaces of constant curvature. We systematically solve the $\kappa$-symmetry condition for D7-brane embeddings into AdS$_4$-sliced AdS$_5\times$S$^5$, and find supersymmetric embeddings in a simple closed form. Up to a critical mass, these embeddings come in surprisingly diverse families, and we present a first study of their (holographic) phenomenology. We carry out the holographic renormalization, compute the one-point functions and attempt a field-theoretic interpretation of the different families. To complete the catalog of supersymmetric D3/D7 configurations, we construct analogous embeddings for flavored N=4 SYM on S$^4$ and dS$_4$.Comment: 37 pages, 9 figure

Characterization of laboratory simulated road paving-like asphalt by high performance liquid chromatography and gas chromatography-mass spectrometry

Prolonged, extensive exposure to asphalt fume has been associated with several adverse health effects. Inhaled polycyclic aromatic hydrocarbons (PAHs) from asphalt fume exposure are of concern. The objective of this study was to characterize both qualitative and quantitative differences between fumes generated at 150°C and 180°C using a well controlled laboratory road paving fume generation system. Fumes were characterized by (1) total vapor and particulate concentration, (2) simulated boiling point profile and (3) specific PAH content. The mean concentrations of the vapor fractions generated at 180°C and 150°C were 23.3 mg/m3 and 11.2 mg/m3, respectively, demonstrating a statistically significant increase in concentration with increasing asphalt temperature. The mean concentrations of the particulate fractions generated at 180°C and 150°C were 42.4 mg/m3 and 28.0 mg/m3, respectively. The simulated boiling point profile did not show a significant qualitative difference between the fumes generated at the two temperatures. Naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and chrysene were identified and quantified from the fumes

High Moisture Extrusion of Oatmeal

Oats are considered to be a highly nutritious breakfast food available to consumers. Heightened consumer interest in functional food products and advances in human nutrition have led to increased levels of interest in the development of new oat based products (Webster and Wood 2011). Developments in technology have led to manufacturing of instant oatmeal, making the product more convenient to consumers. Low moisture extrusion processing is one of the most widely used methods to produce ready to eat breakfast cereals; however, there has been little research carried out to determine if high moisture extrusion methods would be viable. This study evaluated the economic and technical feasibility to utilize high moisture extrusion processing to produce ready to eat oatmeal. A process economics evaluation included measuring the capital requirements to implement the system, process costing to estimate the weighted average unit cost, and net present value of high moisture extrusion production. The capital expense was significantly high. However, the unit cost is comparable to similar products in the market. The net present value of implementing the technology revealed a significant profit over the course of 20 years. Six different technical experiments were performed using a twin screw extruder, each experiment testing for the effect of different extrusion variables on finished product texture. Reference texture data was measured using a control product currently made in the industry using an alternative batch process. The processing parameters which seemed to have the biggest influence on product quality were high rates of water injection, low feed rate, high reaction zone temperature, reduction of particle size, and the use of functional ingredients in the formula. Technical hurdles such as low dwell times, steam plugging, and inconsistent feeding prevented complete starch gelatinization and the steady state of extrusion. Overall, the high moisture methodology did not yield product quality that was consistent and cannot be recommended for use

Biomechanical impact of lower-body PPE on the football athlete: An evaluation and redesign of the knee pad

Although football personal protective equipment (PPE) has developed considerably since the game\u27s conception, knee pad design has lagged behind. Players at all levels of competition are dissatisfied with the device, claiming it impedes performance more than it protects from injury. To date, no published research has studied the football knee pad\u27s effect on athletic performance, and no ergonomic evaluation of the design has been completed. This research first created a new knee pad design based on survey feedback from 138 collegiate and high school football athletes. This new design, called the Vastus And Patella Protection with Range of motion (VAPPR) pad, was then tested for effectiveness. During testing, 10 collegiate athletes performed standardized football drills (Pro-Agility, L-Drill, Broad-Jump) under three padded conditions: unpadded, standard knee pad, VAPPR pad. Results were based on three padded comparisons. First, athletes performed at a higher level unpadded than wearing standard knee pads. Second, no difference in performance existed between testing unpadded and with VAPPR pads. Third, VAPPR pads resulted in superior performance, provided equal protection, and were preferred by athletes when compared to standard knee pads

Galaxy UV-luminosity function and reionization constraints on axion dark matter

If the dark matter (DM) were composed of axions, then structure formation in the Universe would be suppressed below the axion Jeans scale. Using an analytic model for the halo mass function of a mixed DM model with axions and cold dark matter, combined with the abundance-matching technique, we construct the UV-luminosity function. Axions suppress high-$z$ galaxy formation and the UV-luminosity function is truncated at a faintest limiting magnitude. From the UV-luminosity function, we predict the reionization history of the universe and find that axion DM causes reionization to occur at lower redshift. We search for evidence of axions using the Hubble Ultra Deep Field UV-luminosity function in the redshift range $z=6$-$10$, and the optical depth to reionization, $\tau$, as measured from cosmic microwave background polarization. All probes we consider consistently exclude $m_a\lesssim 10^{-23}\text{ eV}$ from contributing more than half of the DM, with our strongest constraint ruling this model out at more than $8\sigma$ significance. In conservative models of reionization a dominant component of DM with $m_a=10^{-22}\text{ eV}$ is in $3\sigma$ tension with the measured value of $\tau$, putting pressure on an axion solution to the cusp-core problem. Tension is reduced to $2\sigma$ for the axion contributing only half of the DM. A future measurement of the UV-luminosity function in the range $z=10$-$13$ by JWST would provide further evidence for or against $m_a=10^{-22}\text{ eV}$. Probing still higher masses of $m_a=10^{-21}\text{ eV}$ will be possible using future measurements of the kinetic Sunyaev-Zel'dovich effect by Advanced ACTPol to constrain the time and duration of reionization.Comment: 17 pages, 8 figures, 2 tables. v2: Minor Changes. References added. Published in MNRA

Additive manufacturing for solid oxide cell electrode fabrication

© The Electrochemical Society.Additive manufacturing can potentially offer a highly-defined electrode microstructure, as well as fast and reproducible electrode fabrication. Selective laser sintering is an additive manufacturing technique in which three-dimensional structures are created by bonding subsequent layers of powder using a laser. Although selective laser sintering can be applied to a wide range of materials, including metals and ceramics, the scientific and technical aspects of the manufacturing parameters and their impact on microstructural evolution during the process are not well understood. In the present study, a novel approach for electrode fabrication using selective laser sintering was evaluated by conducting a proof of concept study. A Ni-patterned fuel electrode was laser sintered on an yttria-stabilized zirconia substrate. The optimization process of laser parameters (laser sintering rate and laser power) and the electrochemical results of a full cell with a laser sintered electrode are presented. The challenges and prospects of using selective laser sintering for solid oxide cell fabrication are discussed