Using silicon diodes for detecting the liquid-vapor interface in hydrogen

Tests were performed using commercially available silicon diode temperature sensors to detect the location of the liquid-vapor interface in hydrogen during ground test programs. Results show that by increasing the current into the sensor, silicon diodes can be used as liquid level point sensors. After cycling the sensors from liquid to vapor several times, it was found that with a 30 mA (milliamps) input current, the sensors respond within 2 seconds by measuring a large voltage difference when transitioning from liquid to vapor across the interface. Nearly instantaneous response resulted during a transition form vapor to liquid. Detailed here are test procedures, experimental results, and guidelines for applying this information to other test facilities

Techniques for improving the accuracy of cyrogenic temperature measurement in ground test programs

The performance of a sensor is often evaluated by determining to what degree of accuracy a measurement can be made using this sensor. The absolute accuracy of a sensor is an important parameter considered when choosing the type of sensor to use in research experiments. Tests were performed to improve the accuracy of cryogenic temperature measurements by calibration of the temperature sensors when installed in their experimental operating environment. The calibration information was then used to correct for temperature sensor measurement errors by adjusting the data acquisition system software. This paper describes a method to improve the accuracy of cryogenic temperature measurements using corrections in the data acquisition system software such that the uncertainty of an individual temperature sensor is improved from plus or minus 0.90 deg R to plus or minus 0.20 deg R over a specified range

Spin-polarized tunneling with Au impurity layers

We have inserted nonmagnetic impurity layers of Au into sputtered AlOx-based magnetic tunnel junctions (F/I/F) and Meservey–Tedrow junctions (S/I/F) in order to study their effect on the tunneling magnetoresistance (TMR) and spin polarization (TSP). Both room temperature TMR and the TSP at 250 mK decay exponentially as an interfacial Au layer is introduced between the barrier and one Co electrode, with 1/e decay lengths λTMR=11±3 Å and λTSP=14±2 Å. We also inserted a 1 Å thick Au layer at a variable distance from the barrier/Co interface and find that both the TMR and TSP recover to the undoped value with the shorter exponential length scales of λTMR=7±4 Å and λTSP=6±2 Å

Higher-order cognitive factors affect subjective but not proprioceptive aspects of self-representation in the rubber hand illusion

In the current study we look at whether subjective and proprioceptive aspects of selfrepresentation are separable components subserved by distinct systems of multisensory integration. We used the rubber hand illusion (RHI) to draw the location of the ‘self’ away from the body, towards extracorporeal space (Out Condition), thereby violating top-down information about the body location. This was compared with the traditional RHI which drew position of the ‘self’ towards the body (In Condition). We were successfully able to draw proprioceptive position of the limbs in and out from the body suggesting body perception is a purely bottom-up process, resistant to top-down effects. Conversely, we found subjective self-representation was altered by the violation of top-down body information – as the strong association of subjective and proprioceptive factors found in the In Condition became non-significant in the Out Condition. Interestingly, we also found evidence that subjective embodiment can modulate tactile perception

Effect of vibration in combined axes on subjective evaluation of ride quality

The effects of simultaneous sinusoidal vibration in the vertical and lateral axes on ratings of discomfort were investigated. The first experiment concentrated on the effects of variation of frequency in the two axes, and the second study concentrated on the effects of amplitude variation in the two axes

Neutron Time of Flight Spectrometry as a Diagnostic Tool for Inertial Electrostatic Confinement Fusion Plasmas

Inertial electrostatic confinement (IEC) is a method for achieving fusion of light nuclei wherein ions are injected into a spherically symmetric system of concentric electrodes. When the innermost electrode is held at negative high voltage with respect to the outer electrode, ions injected into the reactor at cathode (ground) potential accelerate toward the anode where they may undergo collisions with sufficient energy to overcome Coulomb repulsion and achieve nuclear fusion. The most commonly used IEC fusion fuels are deuterium-deuterium (D-D) and deuterium-tritium (D-T). Both fuels undergo fusion reactions that result in production of fast neutrons with distinct energies. Neutron production rates are therefore proportional to fusion reaction rates in fusion reactors burning D-D or D-T fuel, and neutron counts are a useful diagnostic for IEC research. The D-D reaction branches two ways with equal probability, producing either a triton and a proton, or a 3He nucleus and a 2.45 MeV neutron. Tritium produced in the first pathway results in secondary D-T reactions, producing a 4He nucleus and a 14.1 MeV neutron. A more accurate fusion reaction rate can therefore be obtained for deuterium-fueled reactors if the contributions from D-D and D-T reactions can be determined. We present progress made toward a low-cost neutron time of flight spectrometer capable of measuring both neutron production rates and neutron energy, thereby enabling quantification of the D-D, D-T, and total reaction rates for deuterium-fueled IEC reactors

Identifying aging-related genes in mouse hippocampus using gateway nodes

BACKGROUND: High-throughput studies continue to produce volumes of metadata representing valuable sources of information to better guide biological research. With a stronger focus on data generation, analysis models that can readily identify actual signals have not received the same level of attention. This is due in part to high levels of noise and data heterogeneity, along with a lack of sophisticated algorithms for mining useful information. Networks have emerged as a powerful tool for modeling high-throughput data because they are capable of representing not only individual biological elements but also different types of relationships en masse. Moreover, well-established graph theoretic methodology can be applied to network models to increase efficiency and speed of analysis. In this project, we propose a network model that examines temporal data from mouse hippocampus at the transcriptional level via correlation of gene expression. Using this model, we formally define the concept of “gateway” nodes, loosely defined as nodes representing genes co-expressed in multiple states. We show that the proposed network model allows us to identify target genes implicated in hippocampal aging-related processes. RESULTS: By mining gateway genes related to hippocampal aging from networks made from gene expression in young and middle-aged mice, we provide a proof-of-concept of existence and importance of gateway nodes. Additionally, these results highlight how network analysis can act as a supplement to traditional statistical analysis of differentially expressed genes. Finally, we use the gateway nodes identified by our method as well as functional databases and literature to propose new targets for study of aging in the mouse hippocampus. CONCLUSIONS: This research highlights the need for methods of temporal comparison using network models and provides a systems biology approach to extract information from correlation networks of gene expression. Our results identify a number of genes previously implicated in the aging mouse hippocampus related to synaptic plasticity and apoptosis. Additionally, this model identifies a novel set of aging genes previously uncharacterized in the hippocampus. This research can be viewed as a first-step for identifying the processes behind comparative experiments in aging that is applicable to any type of temporal multi-state network

Early career casual teachers: The role of relationships with colleagues in negotiating a teacher identity and developing resilience

Developing relationships with colleagues has been identified as one way to enhance teacher resilience and assists in negotiating a professional identity. For early career teachers, opportunities to participate in induction and mentoring programmes and engage in professional learning can assist in developing these relationships. However, for early career teachers who can only obtain casual work and work intermittently often in many different schools, these opportunities may be limited. This chapter presents longitudinal, qualitative research that explores how early career casual teachers negotiated their teacher identity. Drawing on data from focus groups, semi-structured interviews and reflective tasks, the chapter shares insights into how relationships are pivotal in the development of a strong teacher identity