Preliminary approach to neutron instrument selecction at ESSB-Bilbao based on experience at ISIS molecular spectroscopy group

Collaborative efforts between the Neutronics and Target Design Group at the Instituto de Fusión Nuclear and the Molecular Spectroscopy Group at the ISIS Pulsed Neutron and Muon Source date back to 2012 in the context of the ESS-Bilbao project. The rationale for these joint activities was twofold, namely: to assess the realm of applicability of the low-energy neutron source proposed by ESS-Bilbao - for details; and to explore instrument capabilities for pulsed-neutron techniques in the range 0.05-3 ms, a time range where ESS-Bilbao and ISIS could offer a significant degree of synergy and complementarity. As part of this collaboration, J.P. de Vicente has spent a three-month period within the ISIS Molecular Spectroscopy Group, to gain hands-on experience on the practical aspects of neutron-instrument design and the requisite neutron-transport simulations. To date, these activities have resulted in a joint MEng thesis as well as a number of publications and contributions to national and international conferences. Building upon these previous works, the primary aim of this report is to provide a self-contained discussion of general criteria for instrument selection at ESS-Bilbao, the first accelerator-driven, low-energy neutron source designed in Spain. To this end, Chapter 1 provides a brief overview of the current design parameters of the accelerator and target station. Neutron moderation is covered in Chapter 2, where we take a closer look at two possible target-moderator-reflector configurations and pay special attention to the spectral and temporal characteristics of the resulting neutron pulses. This discussion provides a necessary starting point to assess the operation of ESSB in short- and long-pulse modes. These considerations are further explored in Chapter 3, dealing with the primary characteristics of ESS-Bilbao as a short- or long-pulse facility in terms of accessible dynamic range and spectral resolution. Other practical aspects including background suppression and the use of fast choppers are also discussed. The guiding principles introduced in the first three chapters are put to use in Chapter 4 where we analyse in some detail the capabilities of a small-angle scattering instrument, as well as how specific scientific requirements can be mapped onto the optimal use of ESS-Bilbao for condensed-matter research. Part 2 of the report contains additional supporting documentation, including a description of the ESSB McStas component, a detailed characterisation of moderator response and neutron pulses, and estimates ofparameters associated with the design and operation of neutron choppers. In closing this brief foreword, we wish to thank both ESS-Bilbao and ISIS for their continuing encouragement and support along the way.

Comparative study of two laparoscopic instrument tracker designs for motion analysis and image-guided surgery: a technical evaluation

Laparoscopic instrument tracking systems are a key element in image-guided interventions, which requires high accuracy to be used in a real surgical scenario. In addition, these systems are a suitable option for objective assessment of laparoscopic technical skills based on instrument motion analysis. This study presents a new approach that improves the accuracy of a previously presented system, which applies an optical pose tracking system to laparoscopic practice. A design enhancement of the artificial markers placed on the laparoscopic instrument as well as an improvement of the calibration process are presented as a means to achieve more accurate results. A technical evaluation has been performed in order to compare the accuracy between the previous design and the new approach. Results show a remarkable improvement in the fluctuation error throughout the measurement platform. Moreover, the accumulated distance error and the inclination error have been improved. The tilt range covered by the system is the same for both approaches, from 90º to 7.5º. The relative position error is better for the new approach mainly at close distances to the camera system

Finite element simulation of sandwich panels of laminated plaster and rockwool under mixed mode fracture

Sandwich panels of laminated gypsum and rock wool have shown large pathology of cracking due to excessive slabs deflection. Currently the most widespread use of this material is as vertical elements of division or partition, with no structural function, what justifies that there are no studies on the mechanism of fracture and mechanical properties related to it. Therefore, and in order to reduce the cracking problem, it is necessary to progress in the simulation and prediction of the behaviour under tensile and shear load of such panels, although in typical applications have no structural responsability.

Finite element simulation of sandwich panels of plasterboard and rock wool under mixed mode fracture

This paper presents the results of research on mixed mode fracture of sandwich panels of plasterboard and rock wool. The experimental data of the performed tests are supplied. The specimens were made from commercial panels. Asymmetrical three-point bending tests were performed on notched specimens. Three sizes of geometrically similar specimens were tested for studying the size effect. The paper also includes the numerical simulation of the experimental results by using an embedded cohesive crack model.The involved parameters for modelling are previously measured by standardised tests.

The cup anemometer, a fundamental meteorological instrument for the wind energy industry

The cup anemometer has been used widely by the wind energy industry since its early beginning, covering two fundamental aspects: wind mill performance control and wind energy production forecast. Furthermore, despite modern technological advances such as LIDAR and SODAR, the cup anemometer remains clearly the most used instrument by the wind energy industry. Together with the major advantages of this instrument (precision, robustness), some issues must be taken into account by scientists and researchers when using it. Overspeeding, interaction with stream wakes due to allocation on masts and wind- mills, loss of performance due to wear and tear, change of performance due to different climatic conditions, checking of the maintenance status and recalibration, etc. In the present work a review of the research campaigns carried out at the IDR/UPM Institute to analyze cup anemometer performance is included. Several aspects of this instrument are examined: the calibration process, the loss of performances due to aging and wear and tear, the effect of changes of air density, the rotor aerodynamics, and the harmonic terms contained in the anemometer output signal and their possible relation to the anemometer performances.

A novel scanning lens instrument for evaluating Fresnel lens performance: equipment development and initial results

A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

Diseño y ensayos en tierra de paneles solares para un satélite de órbita baja = Design and testing procedures of a Low Earth Orbit (LEO) satellite solar panels

Debido al reciente incremento de conflictos en el mundo árabe y dado el interés nacional de España en dicha zona, se propone en este proyecto un estudio inicial para el diseño y desarrollo de un microsatélite que ayude al gobierno de España a mantener esa zona bajo observación constante. En el presente trabajo se abarcan todos los subsistemas del satélite, haciéndose un estudio más detallado del subsistema de potencia

Diseño y ensayos en tierra de paneles solares y baterías para un satélite de órbita baja = Design and testing procedures of a Low Earth Orbit (LEO) satellite power subsystem (solar panels and battery)

Las principal conclusión que se puede obtener tras el estudio es que el satélite, tal y como se ha tenido en cuenta, es perfectamente funcional desde el punto de vista eléctrico. Por la parte de la generación de potencia, los paneles son capaces de ofreces una cantidad tal como para que aproximadamente la mitad (en el caso de funcionamiento normal) de esta potencia sea destinada a la carga útil. Además, incluso en los modos de fallo definidos, el valor de potencia dedicada a la carga útil, es suficientemente alta como para que merezca la pena mantener el satélite operativo. Respecto de las baterías, se puede observar por su comportamiento que están, sobredimensionadas y por ello actúan como un elemento regulador del sistema completo, ya que tiene un amplio margen de trabajo por el cual se puede modificar el funcionamiento general. Y esto se demuestra no sólo en cuanto al estado de carga, que para el perfil de consumo constante y el de cuatro pulsos de 120 W por día se mantiene siempre por encima del 99%, si no también en términos de charging rate, el cual se está siempre dentro de los límites establecidos por el fabricante, asegurando una vida operativa acorde con la nominal. Por último, sobre el propio método de simulación se puede extraer que aun no siendo la mejor plataforma donde estudiar estos comportamientos. Presenta el inconveniente de que, en ciertas partes, restringe la flexibilidad a la hora de cambiar múltiples condiciones al mismo tiempo, pero a cambio permite un estudio bastante amplio con un requisito de conocimientos y de complejidad bajo, de manera que habilita a cualquier estudiante a llevar a cabo estudios similares.

The Cup Anemometer, a Fundamental Meteorological Instrument for the Wind Energy Industry. Research at the IDR/UPM Institute

The results of several research campaigns investigating cup anemometer performance carried out since 2008 at the IDR/UPM Institute are included in the present paper. Several analysis of large series of calibrations were done by studying the effect of the rotor’s geometry, climatic conditions during calibration, and anemometers’ ageing. More specific testing campaigns were done regarding the cup anemometer rotor aerodynamics, and the anemometer signals. The effect of the rotor’s geometry on the cup anemometer transfer function has been investigated experimentally and analytically. The analysis of the anemometer’s output signal as a way of monitoring the anemometer status is revealed as a promising procedure for detecting anomalies.

Diseño y ensayos en tierra de paneles solares para un satélite de órbita baja = Design and testing procedures of a Low Earth (LEO)satellite solar panels

El Proyecto Fin De Carrera presentado a continuación contiene una descripción del prediseño del microsatélite de observación terrestre Gaia, particularizando ésta especialmente en el sistema de potencia del mismo. En el presente capítulo se describen los objetivos de la misión expuesta y los requerimientos del satélite objeto de este proyecto.

Accurate Simulation of MPPT Methods Performance When Applied to Commercial Photovoltaic Panels

Anew, simple, and quick-calculationmethodology to obtain a solar panel model, based on the manufacturers’ datasheet, to perform MPPT simulations, is described. The method takes into account variations on the ambient conditions (sun irradiation and solar cells temperature) and allows fast MPPT methods comparison or their performance prediction when applied to a particular solar panel. The feasibility of the described methodology is checked with four different MPPT methods applied to a commercial solar panel, within a day, and under realistic ambient conditions.

Validation of an instrument for injury data collection in strength training

Purpose: To provide for the basis for collecting strength training data using a rigorously validated injury report form. Methods: A group of specialist designed a questionnaire of 45 item grouped into 4 dimensions. Six stages were used to assess face, content, and criterion validity of the weight training injury report form. A 13 members panel assessed the form for face validity, and an expert panel assessed it for content and criterion validity. Panel members were consulted until consensus was reached. A yardstick developed by an expert panel using Intraclass correlation technique was used to assess the reability of the form. Test-retest reliability was assessed with the intraclass correlation coefficient (ICC).The strength training injury report form was developed, and the face, content, and criterion validity successfully assessed. A six step protocol to create a yardstick was also developed to assist in the validation process. Both inter-rater and intra rater reliability results indicated a 98% agreement. Inter-rater reliability agreement of 98% for three injuries. Results: The Cronbach?s alpha of the questionnaire was 0.944 (pmenor que0.01) and the ICC of the entire questionnaire was 0.894 (pmenor que0.01). Conclusion: The questionnaire gathers together enough psychometric properties to be considered a valid and reliable tool for register injury data in strength training, and providing researchers with a basis for future studies in this area. Key Words: data collection; validation; injury prevention; strength training

The Imaging and Slitless Spectroscopy Instrument for Surveys (ISSIS): expected radiometric performance, operation modes and data handling

ISSIS is the instrument for imaging and slitless spectroscopy on-board WSO-UV. In this article, a detailed comparison between ISSIS expected radiometric performance and other ultraviolet instruments is shown. In addition, we present preliminary information on the performance verification tests and on the foreseen procedures for in-flight operation and data handling.

World Space Observatory-Ultraviolet: ISSIS, the imaging instrument

The Imaging and Slitless Spectroscopy Instrument (ISSIS) will be flown as part of the science instrumentation in the World Space Observatory-Ultraviolet (WSO-UV). ISSIS will be the first UV imager to operate in a high Earth orbit from a 2 m class space telescope. In this contribution, the science driving the ISSIS design and the main characteristics of this instrument are presented.

Vehicle-induced loads on traffic sign panels

The determination of the loads on traffic sign panels in the current standards does not, in general, take into account the vehicle-induced loads, as explained by Quinn, Baker and Wright (QBW in what follows) (J. Wind Eng. Ind. Aerodyn. 89 (2001) 831). On the other hand, a report from Cali and Covert (CC) (J. Wind Eng. Ind. Aerodyn. 84 (2000) 87) indicates that in highway sign support structures, vehicle-induced loads have led to premature failures in some cases. The aim of this paper is to present a mathematical model for the vehicle-induced load on a flat sign panel, simple enough to give analytical results, but able to explain the main characteristics of the phenomenon. The results of the theoretical model help to explain the behaviour observed in the experiments performed in previous studies.