Underwater Ant House

The project seeks to design and test and submersible enclosure capable of sustaining oxygen breathing life. A mesh covered in a superhydrophobic coating can both restrain water up to a maximum pressure and retain a direct interface between air and water. Oxygen can transfer over this boundary if there is a sufficient difference in concentrations between the water and air. Multiple designs have been produced with the intent of testing and demonstrating these theories. 3D printing allowed for quick and customizable production of every component. Enclosures were made for testing the maximum allowable pressure and to fit an oxygen sensor. These mostly consisted of a rectangular frame with slotted to fit removable mesh slides. Oxygen concentration experiments were conducted with crickets as live subjects and were designed to analyze the transfer of oxygen through the mesh. The team ran tests to investigate additional factors including coating application and quality, the influence of the mesh substrate material on hydrophobic and coating properties, and mesh sizing influence. Testing indicates that there is sufficient oxygen transfer for small animals to survive. The enclosure can be submerged to approximately four centimeters before failure. This project demonstrates the feasibility of maintaining breathable air using a hydrophobic mesh enclosure and creates the opportunity for further investigation into possible uses of this technology.https://scholarscompass.vcu.edu/capstone/1212/thumbnail.jp

National innovation rates: the evidence for/against domestic institutions

Why are some countries more technologically innovative than others? The dominant explanation amongst political-economists is that domestic institutions determine national innovation rates. However, after decades of research, there is still no agreement on precisely how this happens, exactly which institutions matter, and little aggregate evidence has been produced to support any particular hypothesis. This paper will review the equivocating evidence for domestic institutions explanations of national innovation rates. Its survey will show that, although a specific domestic institution or policy might appear to explain a particular instance of innovation, they generally fail to explain national innovation rates across time and space. Instead, the empirical evidence suggests that certain kinds of international relationships (e.g. capital goods imports, foreign direct investment, educational exchanges) affect national innovation rates in the aggregate, and that these relationships are not themselves determined by domestic institutions. In other words, explaining national innovation rates may not be so much a domestic institutions story as it is an international story.technology; technological; innovation; politics; institutions; research

Performance of polar codes for quantum and private classical communication

We analyze the practical performance of quantum polar codes, by computing rigorous bounds on block error probability and by numerically simulating them. We evaluate our bounds for quantum erasure channels with coding block lengths between 2^10 and 2^20, and we report the results of simulations for quantum erasure channels, quantum depolarizing channels, and "BB84" channels with coding block lengths up to N = 1024. For quantum erasure channels, we observe that high quantum data rates can be achieved for block error rates less than 10^(-4) and that somewhat lower quantum data rates can be achieved for quantum depolarizing and BB84 channels. Our results here also serve as bounds for and simulations of private classical data transmission over these channels, essentially due to Renes' duality bounds for privacy amplification and classical data transmission of complementary observables. Future work might be able to improve upon our numerical results for quantum depolarizing and BB84 channels by employing a polar coding rule other than the heuristic used here.Comment: 8 pages, 6 figures, submission to the 50th Annual Allerton Conference on Communication, Control, and Computing 201

Channelization architecture for wide-band slow light in atomic vapors

We propose a ``channelization'' architecture to achieve wide-band electromagnetically induced transparency (EIT) and ultra-slow light propagation in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong, resonant ``pump'' laser on the atomic medium, which allows slow and unattenuated propagation of a weaker ``signal'' beam, but only when a two-photon resonance condition is satisfied. Our wideband architecture is accomplished by dispersing a wideband signal spatially, transverse to the propagation direction, prior to entering the atomic cell. When particular Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic field with a linear gradient such that the two-photon resonance condition is satisfied for each individual frequency component. Because slow light is a group velocity effect, utilizing differential phase shifts across the spectrum of a light pulse, one must then introduce a slight mismatch from perfect resonance to induce a delay. We present a model which accounts for diffusion of the atoms in the varying magnetic field as well as interaction with levels outside the ideal three-level system on which EIT is based. We find the maximum delay-bandwidth product decreases with bandwidth, and that delay-bandwidth product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a large improvement over the ~1 MHz bandwidths in conventional slow light systems and could be of use in signal processing applications.Comment: Published in SPIE Proceedings, Photonics West 2005 (San Jose, CA, Jan. 22-27, 2005

Therapist self-doubt when facing severe psychopathology in adolescent males

Achieving expertise in psychotherapy is a complex task, fraught with obstacles that impede progress (e.g., cognitive and information processing, accuracy of self-appraisals; Tracey, Wampold, Lichtenberg, & Goodyear, 2014). Contrary to popular opinion, years of experience does not make for an expert therapist. Research indicates that more seasoned therapists are not necessarily more effective than less seasoned therapists in terms of client outcomes. Expertise requires not only time, but also an intention to improve; and the use of appropriate feedback systems. Certain therapist characteristics can reliably predict therapy process and outcome. For example, the degree to which therapists feel uncertain regarding their ability to help clients, known as self-doubt, is a particularly strong predictor of client outcomes (Nissen-Lie, Monsen, Ulleberg, & Rønnestad, 2013). Currently, little is known about therapists’ self-doubt regarding clients’ different presenting problems. There is qualitative evidence that therapists experience the greatest self-doubt in response to clients who are, subjectively, described as high-stakes, unmotivated, violent, aggressive, suicidal, and intensely emotional (Thériault & Gazzola, 2010). Among disorders that manifest these characteristics, conduct disorder (CD) in adolescence is the most representative. This is the first, known study which examined the relation between client characteristics and the expression of self-doubt among therapist trainees in the United States. Participants in the current study read and responded to four vignettes portraying scenarios of adolescent boys with mental illness, in a within-subjects design. Self-doubt was assessed after each vignette using a measure constructed and validated for developing therapists (Orlinsky & Rønnestad, 2005). Ancillary measures assessed participants’ interpersonal reactivity (i.e., perspective taking, empathic concern) as well as their sense of self-efficacy in various counseling behaviors (i.e., session management, counseling challenges). Therapist trainees expressed greatest PSD when working with adolescent males who exhibit CD-Severe, followed by obsessive-compulsive disorder (OCD) and CD-Mild equally, and finally social anxiety disorder (SAD). Overall, clients with externalizing disorders elicit the greatest PSD among therapist trainees. This information may provide evidence for self-doubt as a target in therapist feedback systems in the quest to develop expertise in therapy

NEWS: the near-infrared Echelle for wideband spectroscopy

We present an updated optical and mechanical design of NEWS: the Near-infrared Echelle for Wide-band Spectroscopy (formerly called HiJaK: the High-resolution J, H and K spectrometer), a compact, high-resolution, near-infrared spectrometer for 5-meter class telescopes. NEWS provides a spectral resolution of 60,000 and covers the full 0.8-2.5 micron range in 5 modes. We adopt a compact, lightweight, monolithic design and developed NEWS to be mounted to the instrument cube at the Cassegrain focus of the the new 4.3-meter Discovery Channel Telescope.Comment: Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 99086M (August 9, 2016

Novel design for transparent high-pressure fuel injector nozzles

The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle\u27s injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept

Damped and zero-damped quasinormal modes of charged, nearly extremal black holes

Despite recent progress, the complete understanding of the perturbations of charged, rotating black holes as described by the Kerr-Newman metric remains an open and fundamental problem in relativity. In this study, we explore the existence of families of quasinormal modes of Kerr-Newman black holes whose decay rates limit to zero at extremality, called zero-damped modes in past studies. We review the nearly extremal and WKB approximation methods for spin-weighted scalar fields (governed by the Dudley-Finley equation) and give an accounting of the regimes where scalar zero-damped and damped modes exist. Using Leaver’s continued fraction method, we verify that these approximations give accurate predictions for the frequencies in their regimes of validity. In the nonrotating limit, we argue that gravito-electromagnetic perturbations of nearly extremal Reissner-Nordström black holes have zero-damped modes in addition to the well-known spectrum of damped modes. We provide an analytic formula for the frequencies of these modes, verify their existence using a numerical search, and demonstrate the accuracy of our formula. These results, along with recent numerical studies, point to the existence of a simple universal equation for the frequencies of zero-damped gravito-electromagnetic modes of Kerr-Newman black holes, whose precise form remains an open question