On the determination of near body orbits using mass concentration models

Mathematical model for near-body orbit calculation using mass concentration, perturbation theory, nonlinear equations, geopotentials, and least squares metho

Testing of turbulent seals for rotordynamic coefficients

A facility has been developed for dynamic testing of straight and convergent tapered seals with the capability of measuring the radial and tangential force components which result from a circular centered orbit. The test apparatus causes the seal journal to execute small-eccentricity centered circular orbits within its clearance circle. Dynamic measurements are made and recorded of the seal displacement-vector components, and of the pressure field. The pressure field is integrated to yield seal tangential and radial reaction-force components. Representative test data are provided and discussed for straight seals

A high-Reynolds-number seal test facility: Facility description and preliminary test data

A facility has been developed for testing the leakage and rotordynamic characteristics of interstage-seal configurations for the HPFTP (High Pressure Fuel Turbopump) of the SSME (Space Shuttle Main Engine). Axial Reynolds numbers on the order of 400,000 are realized in the test facility by using a Dupont freon fluid called Halon (CBrF3). The kinematic viscosity of Halon is of the same order as the liquid hydrogen used in the HPFTP. Initial testing has focused on the current flight configurations (a three-segment, stepped unit) and a convergent-taper candidate

Noise resistance of adiabatic quantum computation using random matrix theory

Besides the traditional circuit-based model of quantum computation, several quantum algorithms based on a continuous-time Hamiltonian evolution have recently been introduced, including for instance continuous-time quantum walk algorithms as well as adiabatic quantum algorithms. Unfortunately, very little is known today on the behavior of these Hamiltonian algorithms in the presence of noise. Here, we perform a fully analytical study of the resistance to noise of these algorithms using perturbation theory combined with a theoretical noise model based on random matrices drawn from the Gaussian Orthogonal Ensemble, whose elements vary in time and form a stationary random process.Comment: 9 pages, 3 figure

Quantum tunneling on graphs

We explore the tunneling behavior of a quantum particle on a finite graph, in the presence of an asymptotically large potential. Surprisingly the behavior is governed by the local symmetry of the graph around the wells.Comment: 18 page

Eigenlevel statistics of the quantum adiabatic algorithm

We study the eigenlevel spectrum of quantum adiabatic algorithm for 3-satisfiability problem, focusing on single-solution instances. The properties of the ground state and the associated gap, crucial for determining the running time of the algorithm, are found to be far from the predictions of random matrix theory. The distribution of gaps between the ground and the first excited state shows an abundance of small gaps. Eigenstates from the central part of the spectrum are, on the other hand, well described by random matrix theory.Comment: 8 pages, 10 ps figure

A School-Based Mobile App Intervention for Enhancing Emotion Regulation in Children: Exploratory Trial.

BACKGROUND: Most mental health disorders are first experienced in childhood. The rising rates of mental health difficulties in children highlight the need for innovative approaches to supporting children and preventing these difficulties. School-based digital interventions that address shared risk factors and symptoms, such as emotion dysregulation, present exciting opportunities to enhance mental health support for children on a larger scale. OBJECTIVE: This study investigates the use of a new app-based intervention designed to support children's emotion regulation in schools. The aim is to optimize the usability, acceptability, and utility of the app and explore its scope for implementation with the target user in the school context. METHODS: As part of an interdisciplinary development framework, the app is being evaluated in a 3-month trial across 4 primary schools. In total, 144 children (aged 10-12 years) took part and accessed the intervention app in the classroom or at home. Outcomes regarding usability, acceptability, and implementation opportunities were assessed through digital user data, self-report questionnaires (132/144, 91.6%), and semistructured interviews with children (19/144, 13.2%) and teachers (6/8, 75%). RESULTS: The app usage data showed that 30% (128/426) of the users were returning users. Self-report data indicated that 40.1% (53/132) of the children had not used the app, whereas 57.5% (76/132) had used it once or more. Of the children who had used the app, 67% (51/76) reported that the app was helpful. Interviews with children and teachers suggested positive experiences with the app and that it helped them to calm down and relax. Children reported that they perceived the app as acceptable, usable, and helpful. In terms of the intervention's usability, most features functioned well; however, certain technical issues were reported, which may have led to reduced engagement levels. Teachers not only reported overall positive experiences but also discussed access difficulties and reported a lack of content as one of the main barriers to implementing the app. Having a web-based app significantly enhanced accessibility across devices and settings and provided teachers with more opportunities to use it. We identified the need for new, activating app features in addition to the existing, primarily relaxing ones. The findings indicated that it is possible to use and evaluate an app intervention in the school context and that the app could help enhance children's emotion regulation. We discuss areas for improvement regarding the app, study design, and future implementation strategies. CONCLUSIONS: We share important insights with regard to the development, implementation, and evaluation of a new app for supporting children's emotion regulation in schools. Our results demonstrate that mental health apps represent a promising means to facilitate effective mental health service provision in and outside of the school context. Important lessons learned are shared to support other researchers and clinicians on similar journeys

SPATIAL PRICING EFFICIENCY: THE CASE OF U.S. LONG GRAIN RICE

The spatial rice price relationships for U.S. long grain rough rice are affected by many factors besides the transportation cost between markets, such as milling, processing, cooking and nutritional value as well as physical characteristics. This study applies a time series framework to analyze long run price relationships for Arkansas, Mississippi, Louisiana, Texas and California long grain rice. Johansen's test results showed that at least there are two cointegrating price vectors. However, such a finding is not supported by the ECM model in any of the price series.Demand and Price Analysis,

Universal quantum computation using the discrete time quantum walk

A proof that continuous time quantum walks are universal for quantum computation, using unweighted graphs of low degree, has recently been presented by Childs [PRL 102 180501 (2009)]. We present a version based instead on the discrete time quantum walk. We show the discrete time quantum walk is able to implement the same universal gate set and thus both discrete and continuous time quantum walks are computational primitives. Additionally we give a set of components on which the discrete time quantum walk provides perfect state transfer.Comment: 9 pages, 10 figures. Updated after referee comments - Section V expanded and minor changes to other parts of the tex