How to determine an exomoon's sense of orbital motion

We present two methods to determine an exomoon's sense of orbital motion (SOM), one with respect to the planet's circumstellar orbit and one with respect to the planetary rotation. Our simulations show that the required measurements will be possible with the European Extremely Large Telescope (E-ELT). The first method relies on mutual planet-moon events during stellar transits. Eclipses with the moon passing behind (in front of) the planet will be late (early) with regard to the moon's mean orbital period due to the finite speed of light. This "transit timing dichotomy" (TTD) determines an exomoon's SOM with respect to the circumstellar motion. For the ten largest moons in the solar system, TTDs range between 2 and 12 s. The E-ELT will enable such measurements for Earth-sized moons around nearby stars. The second method measures distortions in the IR spectrum of the rotating giant planet when it is transited by its moon. This Rossiter-McLaughlin effect (RME) in the planetary spectrum reveals the angle between the planetary equator and the moon's circumplanetary orbital plane, and therefore unveils the moon's SOM with respect to the planet's rotation. A reasonably large moon transiting a directly imaged planet like beta Pic b causes an RME amplitude of almost 100 m/s, about twice the stellar RME amplitude of the transiting exoplanet HD209458b. Both new methods can be used to probe the origin of exomoons, that is, whether they are regular or irregular in nature.Comment: accepted by ApJ Letters, 6 pages, 5 figures (2 color

Modest Automorphisms of Presburger Arithmetic

It is interesting to consider whether a structure can be expanded by an automorphism so that one obtains a nice description of the expanded structure\u27s first-order properties. In this dissertation, we study some such expansions of models of Presburger arithmetic. Building on some of the work of Harnik (1986) and Llewellyn-Jones (2001), in Chapter 2 we use a back-and-forth construction to obtain two automorphisms of sufficiently saturated models of Presburger arithmetic. These constructions are done first in the quotient of the Presburger structure by the integers (which is a divisible ordered abelian group with some added structure), and then lifted to the full Presburger structure. The first automorphism we construct has special tightly controlled properties that enable us in Chapters 4 and 5 to prove quantifier elimination, decidability, and axiomatizability for both the quotient and the Presburger structure expanded by this automorphism, with explicit axiomatizations given in Chapter 3. The second automorphism is maximal in the sense that its fixed-point set consists only of the standard integers, and has certain properties in common with those of the first automorphism, but we have not attempted to prove quantifier elimination for structures expanded by this automorphism. In Chapters 6 and 7, we use the quantifier elimination results to describe the definable sets and algebraic closure of the quotient structure and Presburger structure expanded by the first automorphism. This allows us in Chapter 8 to show that the DP-rank in both cases is 2. Finally, in the concluding chapter, we describe some areas of possible future research

Back to the Future: ABA Law School Accreditation in the 21st Century and America\u27s First Law School\u27s Battle to Survive in the 1970s

In the mid-1970s, the ABA threatened to pull accreditation from the College of William & Mary’s law school. The ABA’s motives were questioned as it had never taken this step before. Would a more aggressive 21st century ABA have stripped accreditation from well-established schools like William & Mary? The reader can be the judge

The relationship between peak power and leg size in mountain bike cyclists

The relationship between peak power and leg size in mountain bike cyclist

Assessment of a Microsoft Kinect-based 3D scanning system for taking body segment girth measurements : a comparison to ISAK and ISO standards

Use of anthropometric data to infer sporting performance is increasing in popularity, particularly within elite sport programmes. Measurement typically follows standards set by the International Society for the Advancement of Kinanthropometry (ISAK). However, such techniques are time consuming, which reduces their practicality. Schranz et al. recently suggested 3D body scanners could replace current measurement techniques; however, current systems are costly. Recent interest in natural user interaction has led to a range of low-cost depth cameras capable of producing 3D body scans, from which anthropometrics can be calculated. A scanning system comprising 4 depth cameras was used to scan 4 cylinders, representative of the body segments. Girth measurements were calculated from the 3D scans and compared to gold standard measurements. Requirements of a Level 1 ISAK practitioner were met in all 4 cylinders, and ISO standards for scan-derived girth measurements were met in the 2 larger cylinders only. A fixed measurement bias was identified that could be corrected with a simple offset factor. Further work is required to determine comparable performance across a wider range of measurements performed upon living participants. Nevertheless, findings of the study suggest such a system offers many advantages over current techniques, having a range of potential application

Validity and repeatability of a depth camera based surface imaging system for thigh volume measurement

Complex anthropometric measures, such as area and volume, can identify changes in body size and shape that are not detectable with traditional anthropometric measures of lengths, breadths, skinfolds and girths. However, taking these more complex measures with manual techniques (tape measurement and water displacement) is often unsuitable. Three dimensional (3D) surface imaging systems are quick and accurate alternatives to manual techniques but their use is restricted by cost, complexity and limited access. We have developed a novel low cost, accessible and portable 3D surface imaging system based on consumer depth cameras. The aim of this study was to determine the validity and repeatability of the system in the measurement of thigh volume. The thigh volumes of 36 participants were measured with the depth camera system and a high precision commercially available 3D surface imaging system (3dMD). The depth camera system used within this study is highly repeatable (technical error of measurement of < 1.0% intra-calibration and ~ 2.0% inter-calibration) but systematically overestimates (~6%) thigh volume when compared to the 3dMD system. This suggests poor agreement yet a close relationship, which once corrected can yield a usable thigh volume measurement. Keywords : Kinanthropometry, Anthropometry, Depth Camera, 3D Body Scanning, Surface Imaging

Relay exchanges in elite short track speed skating

In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. Typically executed every 1 ½ laps, it is the belief of skaters and coaches that during this period of the race, time can be gained or lost due to the execution of the relay exchange. As such, the aim of this study was to examine the influence of the relay exchange on a team's progression through a 5000 m relay race. Using data collected from three World Cup relay events during the 2012-13 season, the time taken to complete the straight for the scenarios with and without the relay exchange were compared at different skating speeds for the corner exit prior to the straight. Overall, the influence of the relay exchange was found to be dependent on this corner exit speed. At slower corner exit speeds (12.01 - 13.5 m/s), relay exchange straight times were significantly faster than the free skating scenario (P < 0.01). Whilst at faster corner exit speeds (14.01 - 15 m/s), straight times were significantly slower (P < 0.001). The findings of this study suggest that the current norm of executing relay exchanges every 1 ½ laps may not be optimal. Instead, varying the frequency of relay exchange execution throughout the race could allow: (1) time to be gained relative to other teams; and (2) facilitate other race strategies by providing an improved opportunity to overtake

Opto-thermal analysis of solar thermal absorber coatings under concentrated solar radiation based on spectral measurement techniques

El cambio climático es uno de los principales retos a los que se enfrenta la humanidad en el siglo XXI. Es imprescindible aprovechar la energía solar para descarbonizar el sistema energético mundial. Se espera que la tecnología de concentración solar térmica (CST) desempeñe un papel decisivo en el suministro de calor para procesos industriales de media y alta temperatura. Los receptores térmicos y los recubrimientos absorbentes solares térmicos son componentes claves de los sistemas CST. La monitorización de las características optotérmicas de dichos recubrimientos, tales como la absorbancia solar, la emitancia térmica y la temperatura de superficie, es crítica para el funcionamiento eficiente y durable de dichos sistemas. El objetivo principal de esta tesis doctoral es desarrollar un marco para el análisis óptico-térmico de los recubrimientos absorbentes solares térmicos para CST. El análisis óptico-térmico se basa principalmente en técnicas de medición infrarroja, como la espectrofotometría y la radiometría multiespectral. El análisis se desarrolla para materiales relevantes, primero en condiciones de laboratorio, tanto a temperatura ambiente como de funcionamiento, hasta 800 °C. Se introduce una nueva técnica de medición para la caracterización opto-térmica in situ de recubrimientos absorbentes solares térmicos en sistemas de receptor central. El rendimiento óptico-térmico de un recubrimiento absorbente solar térmico para aplicaciones CSP es sensible al factor de concentración Cx y a la temperatura de la superficie T. Mientras que los recubrimientos solares selectivos son definitivamente relevantes para los colectores cilindro-parabólicos, los recubrimientos negros con una alta absorbancia solar son más relevantes para los sistemas de receptor central, debido al mayor factor de concentración. Las campañas de medición de intercomparación han demostrado que los valores de absorbancia solar derivados de las mediciones espectrales a temperatura ambiente son reproducibles con una desviación estándar por debajo del 1%, para los recubrimientos selectivos solares, los recubrimientos negros, el Haynes 230 (H230) oxidado y el carburo de silicio (SiC). Para los mismos materiales, se observó una desviación estándar superior de ~ 3% para los valores de emitancia térmica derivados de mediciones espectrales a temperatura ambiente. La comparación de los valores de emitancia térmica derivados de la temperatura ambiente y de funcionamiento hasta 800 °C demuestran un acuerdo bastante coherente para H230 oxidado, los recubrimientos negros y SiC. La caracterización opto-térmica a distancia de materiales grises como el H230 oxidado y los recubrimientos negros es factible en un Sistema Receptor Central utilizando termografía infrarroja de onda corta. Se analizaron respectivamente dos configuraciones para condiciones de funcionamiento con y sin radiación solar concentrada. Abstract Climate change is one of the major challenge faced by mankind in the 21st century. Solar energy must be harnessed for decarbonising the global energy system. Concentrated Solar Thermal (CST) technology is expected to play a decisive role in supplying heat for medium to high temperature industrial processes. Thermal receivers and solar thermal absorber coatings are key components in CST systems. The monitoring of coating opto-thermal characteristics, such as solar absorptance, thermal emittance and surface temperature, is critical for the efficient and durable operation of such systems. The main objective of this doctoral thesis is to develop a framework for the opto-thermal analysis of solar thermal absorber coatings for CST. The opto-thermal analysis is mostly based on infrared measurement techniques, such as spectrophotometry and multispectral radiometry. The analysis is developed for relevant materials, first under laboratory conditions, both at ambient and operating temperature, up to 800 °C. A new measurement technique is introduced for the in-situ opto-thermal characterisation of solar thermal absorber coatings in Central Receiver Systems (CRS). The opto-thermal performance of a solar thermal absorber coating for CSP applications is sensitive to the concentration factor Cx and the surface temperature T. While solar selective coatings are definitely relevant for parabolic trough collectors, high solar absorptance black coatings are more relevant for central receiver systems, due to the higher concentration factor. Intercomparison measurement campaigns have shown that solar absorptance values derived from room temperature spectral measurements are reproducible with a low standard deviation of 1%, for solar selective coatings, black coatings, oxidized Haynes 230 (H230) and silicon carbide (SiC). For the same materials, a higher standard deviation of ~ 3% was observed for thermal emittance values derived from room temperature spectral measurements. The comparison of thermal emittance values derived from room and operating temperature up to 800 °C show a rather consistent agreement for oxidised H 230, black coatings and SiC. The remote opto-thermal characterization of grey materials such as oxidised H230 and black coatings is feasible in a Central Receiver System using shortwave infrared thermography. Two configurations were respectively analysed for on-sun and off-sun operating conditions.Doctorado en Tecnología de Invernaderos e Ingeniería Industrial (RD99/11) (8909

Assessing the suitability of the Microsoft Kinect for calculating person specific body segment parameters

Many biomechanical and medical analyses rely on the availability of reliable body segment parameter estimates. Current techniques typically take many manual measurements of the human body, in conjunction with geometric models or regression equations. However, such techniques are often criticised. 3D scanning offers many advantages, but current systems are prohibitively complex and costly. The recent interest in natural user interaction (NUI) has led to the development of low cost (-£200) sensors capable of 3D body scanning, however, there has been little consideration of their validity. A scanning system comprising four Microsoft Kinect sensors (a typical NUI sensor) was used to scan twelve living male participants three times. Volume estimates from the system were compared to those from a geometric modelling technique. Results demonstrated high reliability (ICC >0.7, TEM <1%) and presence of a systematic measurement offset (0.001m3) suggesting the system would be well received by healthcare and sports communities