Design of a Torque Current Generator for Strapdown Gyroscopes

The design, analysis, and experimental evaluation of an optimum performance torque current generator for use with strapdown gyroscopes, is presented. Among the criteria used to evaluate the design were the following: (1) steady-state accuracy; (2) margins of stability against self-oscillation; (3) temperature variations; (4) aging; (5) static errors drift errors, and transient errors, (6) classical frequency and time domain characteristics; and (7) the equivalent noise at the input of the comparater operational amplifier. The DC feedback loop of the torque current generator was approximated as a second-order system. Stability calculations for gain margins are discussed. Circuit diagrams are shown and block diagrams showing the implementation of the torque current generator are discussed

Thermal barrier coating life prediction model

The objectives of this program are to determine the predominant modes of degradation of a plasma sprayed thermal barrier coating system, and then to develop and verify life prediction models accounting for these degradation modes. The program is divided into two phases, each consisting of several tasks. The work in Phase 1 is aimed at identifying the relative importance of the various failure modes, and developing and verifying life prediction model(s) for the predominant model for a thermal barrier coating system. Two possible predominant failure mechanisms being evaluated are bond coat oxidation and bond coat creep. The work in Phase 2 will develop design-capable, causal, life prediction models for thermomechanical and thermochemical failure modes, and for the exceptional conditions of foreign object damage and erosion

Advertising paid and unpaid job roles in sport: an updated position statement from the UK Strength and Conditioning Association

Editoria

Elastic anomalies due to structural phase transitions in mechanoluminescent SrAl₂O₄:Eu

Elastic and anelastic properties of a ceramic sample of elasticoluminescentSrAl₂O₄:Eu have been characterized as a function of temperature by resonant ultrasound spectroscopy.RUS facilities in Cambridge were established with the support of grant to M.A.C. from the Natural Environment Research Council of Great Britain, Grant No. NE/ B505738/1. C.J.H. and M.A.C. acknowledge the support of the Leverhulme Trust in the form of a Visiting Professorship for C.J.H. R.L.W. and Y.L. gratefully acknowledge the financial support from the Australian Research Council in the form of ARC Discovery Grants

Vibration-tolerant narrow-linewidth semiconductor disk laser using novel frequency-stabilisation schemes

This paper will present developments in narrow-linewidth semiconductor-disk-laser systems using novel frequency-stabilisation schemes for reduced sensitivity to mechanical vibrations, a critical requirement for mobile applications. Narrow-linewidth single-frequency lasers are required for a range of applications including metrology and high-resolution spectroscopy. Stabilisation of the laser was achieved using a monolithic fibre-optic ring resonator with free spectral range of 181 MHz and finesse of 52 to act as passive reference cavity for the laser. Such a cavity can operate over a broad wavelength range and is immune to a wide band of vibrational frequency noise due to its monolithic implementation. The frequency noise of the locked system has been measured and compared to typical Fabry-Perot-locked lasers using vibration equipment to simulate harsh environments, and analysed here. Locked linewidths of < 40 kHz have been achieved. These developments offer a portable, narrow-linewidth laser system for harsh environments that can be flexibly designed for a range of applications

Sexual assault: Exploring real-time consequences the next day and in subsequent days

Approximately 15-20% of adult women in the United States have been sexually assaulted. Given the high prevalence of sexual assault, it becomes increasingly important to understand immediate responses to sexual assault. A lack of information prior to sexual assaults contributes to a literature that is unable to showcase the presence and amount of change. A tendency to rely on comparisons between people, instead of the collection of multiple moments of a single person over time, will continue to point toward imprecise, statistical “average” reactions to sexual assaults. Prior methodological approaches lead to broad overgeneralizations about sexual assault survivors that may undermine their unique experiences in the aftermath of an assault. The present study extends the existing literature with access to unprecedented data gathered on the days before and immediately after someone survived a sexual assault. To our knowledge, there are no studies capturing prior functioning and near immediate psychological reactions of sexual assault survivors. In the present study, each night over the course of three weeks, we asked college students (n = 186) to report on their sexual activity and well-being. Six women and one man reported being sexually assaulted at least once. We examined psychological experiences on the days before and after sexual assaults (including negative and positive affect, social anxiety, self-esteem, emotion expressive suppression, and cognitive reappraisal). To examine sexual assault reactions, we used various descriptive approaches. Our results suggest that before and after being assaulted, survivors showed no consistent response in subjective well-being. We failed to find a prototypical psychological profile. Despite the small sample, our results raise important questions and offer future hypotheses about individual differences in responses to sexual assault