Geodesic motion in a stationary dihole spacetime

The knowledge of the properties of the different exact solutions modeling binary systems, is a necessary step towards the classification of physically suitable solutions and its corresponding limits of applicability. In the present paper, we perform an analysis of the geodesics around two counter--rotating Kerr--Newman black holes endowed with opposite electric charges, which achieve equilibrium by means of a strut between their constituents. We find that bounded and unbounded orbits are possible. However, test particles may cross between the black holes only if their angular momentum equals zero, otherwise, there exist a repulsive potential, which prohibits such orbits. Two important aspects are pointed out for these trajectories: ({\it i}) the motion of photons is affected once crossing the strut; and ({\it ii}) massive particles exhibit oscillatory motion, as a first analog of the Sitnikov problem in general relativity. The radius of the innermost stable circular orbit as a function of the physical parameters of the black holes is also investigated.Comment: 10 pages, 9 figure

Method of measuring field funneling and range straggling in semiconductor charge-collecting junctions

Electric-field funneling length is measured while irradiating a semiconductor charge-collecting junction with electron-hole-pair generating charged particles at a first junction bias voltage. The bias voltage is then reduced to a second level in order to reduce the depth of the depletion region such that the total charge can no longer be collected by drift and measured in the energy band previously displayed in the multichannel analyzer. This is representative of the maximum electric field funneling length which may be calculated by measuring the difference at the second bias voltage level of the depletion width and the ion penetration range. The bias voltage is further lowered to a third level at which the particles are collected over a spread of energy levels while at least some of the particles are still collected at the selected energy level. From this the different depths of penetration of the particles are determined while additional effects due to diffusion are minimized

Design and Characterization of Thin Stainless Steel Burst Disks for Increasing Two-Stage Light Gas Launcher Efficiency

Laser etched 300 series Stainless Steel Burst Disks (SSBD) ranging between 0.178 mm (0.007-in.) and 0.508mm (0.020-in.) thick were designed for use in a 17-caliber two-stage light gas launcher. First, a disk manufacturing method was selected using a combination of wire electrical discharge machining (EDM) to form the blank disks and laser etching to define the pedaling fracture pattern. Second, a replaceable insert was designed to go between the SSDB and the barrel. This insert reduced the stress concentration between the SSBD and the barrel, providing a place for the petals of the SSDB to open, and protecting the rifling on the inside of the barrel. Thereafter, a design of experiments was implemented to test and characterize the burst characteristics of SSBDs. Extensive hydrostatic burst testing of the SSBDs was performed to complete the design of experiments study with one-hundred and seven burst tests. The experiment simultaneously tested the effects of the following: two SSBD material states (full hard, annealed); five SSBD thicknesses 0.178, 0.254, 0.305, 0.381 mm (0.007, 0.010, 0.012, 0.015, 0.020-in.); two grain directions relative); number of times the laser etch pattern was repeated (varies between 5-200 times); two heat sink configurations (with and without heat sink); and, two barrel configurations (with and without insert). These tests resulted in the quantification of the relationship between SSBD thickness, laser etch parameters, and desired burst pressure. Of the factors investigated only thickness and number of laser etches were needed to develop a mathematical relationship predicting hydrostatic burst pressure of disks using the same barrel configuration. The fracture surfaces of two representative SSBD bursts were then investigated with a scanning electron microscope, one burst hydrostatically in a fixture and another dynamically in the launcher. The fracture analysis verified that both burst conditions resulted in a ductile overload failure indicated by transgranular microvoid coalescence, non-fragmenting rupture and mixed tensile and shear failure modes, regardless of the material states tested. More testing is underway to determine the relationship between SSBD burst pressure and projectile velocity

The synergy between bounded-distance HMM and spectral subtraction for robust speech recognition

Additive noise generates important losses in automatic speech recognition systems. In this paper, we show that one of the causes contributing to these losses is the fact that conventional recognisers take into consideration feature values that are outliers. The method that we call bounded-distance HMM is a suitable method to avoid that outliers contribute to the recogniser decision. However, this method just deals with outliers, leaving the remaining features unaltered. In contrast, spectral subtraction is able to correct all the features at the expense of introducing some artifacts that, as shown in the paper, cause a larger number of outliers. As a result, we find that bounded-distance HMM and spectral subtraction complement each other well. A comprehensive experimental evaluation was conducted, considering several well-known ASR tasks (of different complexities) and numerous noise types and SNRs. The achieved results show that the suggested combination generally outperforms both the bounded-distance HMM and spectral subtraction individually. Furthermore, the obtained improvements, especially for low and medium SNRs, are larger than the sum of the improvements individually obtained by bounded-distance HMM and spectral subtraction.Publicad

Measuring mental health and wellbeing outcomes for children and adolescents to inform practice and policy:a review of child self-report measures

There is a growing appetite for mental health and wellbeing outcome measures that can inform clinical practice at individual and service levels, including use for local and national benchmarking. Despite a varied literature on child mental health and wellbeing outcome measures that focus on psychometric properties alone, no reviews exist that appraise the availability of psychometric evidence and suitability for use in routine practice in child and adolescent mental health services (CAMHS) including key implementation issues. This paper aimed to present the findings of the first review that evaluates existing broadband measures of mental health and wellbeing outcomes in terms of these criteria. The following steps were implemented in order to select measures suitable for use in routine practice: literature database searches, consultation with stakeholders, application of inclusion and exclusion criteria, secondary searches and filtering. Subsequently, detailed reviews of the retained measures’ psychometric properties and implementation features were carried out. 11 measures were identified as having potential for use in routine practice and meeting most of the key criteria: 1) Achenbach System of Empirically Based Assessment, 2) Beck Youth Inventories, 3) Behavior Assessment System for Children, 4) Behavioral and Emotional Rating Scale, 5) Child Health Questionnaire, 6) Child Symptom Inventories, 7) Health of the National Outcome Scale for Children and Adolescents, 8) Kidscreen, 9) Pediatric Symptom Checklist, 10) Strengths and Difficulties Questionnaire, 11) Youth Outcome Questionnaire. However, all existing measures identified had limitations as well as strengths. Furthermore, none had sufficient psychometric evidence available to demonstrate that they could reliably measure both severity and change over time in key groups. The review suggests a way of rigorously evaluating the growing number of broadband self-report mental health outcome measures against standards of feasibility and psychometric credibility in relation to use for practice and policy

Method of measuring field funneling and range straggling in semiconductor charge-collecting junctions

Electric-field funneling length is measured while irradiating a semiconductor charge-collecting junction with electron-hole-pair generating charged particles at a first junction bias voltage. The bias voltage is then reduced to a second level in order to reduce the depth of the depletion region such that the total charge can no longer be collected by drift and measured in the energy band previously displayed in the multichannel analyzer. This is representative of the maximum electric field funnelling length which may be calculated by measuring the difference at the second bias voltage level of the depletion width and the ion penetration range. The bias voltage is further lowered to a third level at which the particles are collected over a spread of energy levels while at least some of the particles are still collected at the selected energy level. From this the different depths of penetration of the particles are determined while additional effects due to diffusion are minimized

Anàlisi d'estratègies d'identificació i prevenció dels trastorns de conducta a l'aula

Curs 2013-2014Aquest treball, vol exemplificar la importància que té actualment l’aplicació de diverses estratègies d’intervenció per identificar i disminuir la presència de trastorns de conducta a les aules. Des d’un punt de vista inclusiu, la detecció i el tractament d’aquests problemes s’ha convertit en un dels reptes més importants en l’educació i per aquest motiu volem oferir al professorat un seguit de metodologies i tècniques amb les quals puguin reconèixer en cursos inicials a tots aquells alumnes susceptibles a la realització d’una intervenció preventiva.This project wants to illustrate the importance of intervention strategies to identify and reduce the presence of behavioural disorders in classrooms. From an inclusive point of view, detection and treatment of these problems has become a major challenge in education, and that is why we offer teachers a range of methodologies and techniques to recognise succeptible pupils on initial courses in order to make a preventive intervention

Uncertainty decoding on Frequency Filtered parameters for robust ASR

The use of feature enhancement techniques to obtain estimates of the clean parameters is a common approach for robust automatic speech recognition (ASR). However, the decoding algorithm typically ignores how accurate these estimates are. Uncertainty decoding methods incorporate this type of information. In this paper, we develop a formulation of the uncertainty decoding paradigm for Frequency Filtered (FF) parameters using spectral subtraction as a feature enhancement method. Additionally, we show that the uncertainty decoding method for FF parameters admits a simple interpretation as a spectral weighting method that assigns more importance to the most reliable spectral components. Furthermore, we suggest combining this method with SSBD-HMM (Spectral Subtraction and Bounded Distance HMM), one recently proposed technique that is able to compensate for the effects of features that are highly contaminated (outliers). This combination pursues two objectives: to improve the results achieved by uncertainty decoding methods and to determine which part of the improvements is due to compensating for the effects of outliers and which part is due to compensating for other less deteriorated features.Publicad