Measurement and Analysis of Axial End Forces in a Full-Length Prototype of LHC Main Dipole Magnets

A full-length, twin aperture prototype (MBP2N1) dipole magnet for the LHC project was assembled at CERN with collared coils delivered by industry. The design of this prototype is close to that foreseen for the dipole series manufacture as far the coil geometry and that of the yoke components are concerned. The bolts that transfer the axial magnetic forces from the coil ends to the cold mass end plates were instrumented to verify the axial coil support. These axial forces were initially measured after partial assembly, during a standard and an accelerated cool down Introduction to 1.9 K, and during magnet excitation up to 9.2 T. High force levels were observed, triggering a comparison with analytical models and measurements routinely made on 1-m single aperture dipole models. The prototype magnet was re-assembled with lower initial axial force settings and with additional instrumentation, to monitor these forces during the entire assembly process, and re-tested, to possibly correlate axial forces with training behaviour. This paper reports about the experimental observations and provides models towards their understandin

Remote Inspection, Measurement and Handling for LHC

Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-date and future development plans

Development of a Passive Mini-Direct Ethanol Fuel Cell: Effect of Mea Assembly Parameters by Hot Pressure

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2of PtRu/C) and the cathode (0.8 mg cm -2of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

Development of a passive mini-direct ethanol fuel cell : effect of mea assembly parameters by hot pressure.

This paper presents preliminary results on the design, construction and evaluation of a passive mini direct ethanol fuel cell (DEFC), capillary fed with 2 mol l-1 aqueous ethanol, at a rate of 2.03 μL min-1, and air oxygen in the cathode through an air vent. Parameters such as pressure, temperature and time of manufacturing a membrane-electrode assembly (MEA) by hot-pressure were evaluated. As the electrode holder used a 0.25 cm2 carbon tissue which was deposited on the catalytic layer (C. L.) for both the anode (0.8 mg cm-2 of PtRu/C) and the cathode (0.8 mg cm-2 of Pt/C), Nafi on® 115 membranes were used as the electrolyte. The results show, an average power density of 302 μWcm2 under the best conditions used, a catalytic layer with a Nafi on percentage of 50% at 25 °C. A temperature of 125 °C, a pressure of 49.2 Kg/cm2, and 90 seconds duration were used to obtain the MEA

Semi-automatic detection of hepatic tumor in computed tomography images

In this work, the main purpose is develop a computational segmentation strategy for liver tumor semiautomatic detection. This strategy considers three-dimensional computed tomography images and it consists of techniques application that, on the one hand, diminish the noise and detect the edges of the objects present in those images and, on the other hand, generate the liver tumor morphology. For this, the sequence of techniques composed of gaussian smoothing, gradient magnitude, median filter, region growing and binary morphological dilation are used. The value obtained, for the metric called Dice score, show a good correlation between manual segmentation, performed by a hepatologist, and the tumor segmentation obtained using the proposed technique. This type of segmentation is the extreme utility for the characterization of hepatic tumors and the planning of the clinical behavior to be followed in the treatment of this human liver disease

Smart operator for the human liver automatic segmentation, present in medical images

The segmentation of the human body organ called liver is a highly challenging problem due to the noise, artifacts and the low contrast exhibited by the anatomical structures located around the liver and that are present in digital images, generated by any modality of medical images. The main modalities are: ultrasound, nuclear emission, magnetic resonance and the gold standard called multi-slice computed tomography. In this paper, with the objective of to address this problem, we consider multi-slice computed tomography images and we propose an automatic strategy based on two phases. In the first phase, a digital filtering bank is used for diminishing the noise effect and the artifacts impact in the quality of images. In the second phase, called liver detection, we use a smart operator based on least squares support vector machines for generating both the morphology and the volume of liver. The application of this strategy allows generating the morphology of the liver in a precise and efficient manner as it was demonstrated by the metrics used to assess its performance. These results are very important in clinical-surgical processes where both the shape and volume of liver are vital for monitoring some liver diseases that can affect the normal liver physiology

Accuracy and precision of GPS receivers under forest canopies in a mountain environment

Abstract Georeferencing field plots by means of GPS/GLONASS techniques is becoming compulsory for many applications concerning forest management and inventory. True coordinates obtained in a total station traverse were compared against GPS/GLONASS occupations computed from one navigation-grade and three survey-grade receivers. Records were taken under a high Pinus sylvestris L. forest canopy situated in a mountainous area in central Spain. The horizontal component of the absolute error was a better descriptor of the performance of GPS/GLONASS receivers compared to the precision computed by the proprietary software. The vertical component of absolute error also failed to show the effects revealed when the horizontal one was studied. These differences might be critical for applications involving high-demanding surveys, in which a comparison against a terrestrially surveyed ground truth is still mandatory for accuracy assessment in forested mountainous areas. Moreover, a comparison of diverse Differential GPS/GLONASS techniques showed that the effect of lengthening the baseline and lowering the logging rate was not significant in this study. Differences among methods and receivers were only observed for recording periods between 5 and 15 minutes. The hand-held receiver was inappropriate for plot establishment due to its inaccuracy and a low rate of fixed solutions, though it may be used for forest campaigns tolerating low precision or permitting the employment of periods of 20 minutes or longer for plot mensuration. Additional key words: forest inventory; georeferencing; global navigation satellite system (GNSS) (GLONASS); optimum observing time. Resumen Exactitud y precisión de receptores GPS bajo cubiertas forestales en ambientes montañosos La georreferenciación de trabajos de campo por medio de GPS/GLONASS es cada vez más necesaria para muchas aplicaciones en la gestión e inventario forestal. Se compararon coordenadas reales levantadas con estación total con las obtenidas por un navegador y tres equipos de calidad topográfica. Los registros se efectuaron bajo una masa de Pinus sylvestris L. del Sistema Central, España. La componente horizontal del error absoluto resultó ser un mejor descriptor de la calidad de las mediciones de los receptores GPS/GLONASS que los valores de precisión proporcionados por el software de los equipos. La componente vertical del error absoluto no mostró los efectos revelados por la componente horizontal. Estas diferencias pueden ser críticas para trabajos que requieran levantamientos topográficos de precisión, en los cuáles un contraste con itinerarios de validación sobre el terreno sigue siendo indispensable para calcular la exactitud en áreas forestales montañosas. Por otro lado, la comparación de diversas técnicas de GPS/GLO-NASS diferencial mostró que los cambios en la longitud de la línea base y de la tasa de registros no fueron significativos en este estudio. Sólo se observaron diferencias ente los métodos y receptores para tiempos de registro de 5 a 15 minutos. El navegador no resultó adecuado para el establecimiento de parcelas debido a la inexactitud y baja tasa de soluciones fijadas, pero puede ser utilizado en campañas que toleren bajas precisiones y permitan tiempos de registro iguales o superiores a 20 minutos para las medias forestales. Palabras clave adicionales

Characterisation of fatty acyl reductases of sunflower (Helianthus annuus L.) seed

Long and very long chain fatty alcohols are produced from their corresponding acyl-CoAs through the activity of fatty acyl reductases (FARs). Fatty alcohols are important components of the cuticle that protects aerial plant organs, and they are metabolic intermediates in the synthesis of the wax esters in the hull of sunflower (Helianthus annuus) seeds. Genes encoding 4 different FARs (named HaFAR2, HaFAR3, HaFAR4 and HaFAR5) were identified using BLAST, and studies showed that four of the genes were expressed in seed hulls. In this study, the structure and location of sunflower FAR proteins were determined. They were also expressed exogenously in Saccharomyces cerevisiae to evaluate their substrate specificity based on the fatty alcohols synthesized by the transformed yeasts. Three of the four enzymes tested showed activity in yeast. HaFAR3 produced C18, C20 and C22 saturated alcohols, whereas HaFAR4 and HaFAR5 produced C24 and C26 saturated alcohols. The involvement of these genes in the synthesis of sunflower seed wax esters was addressed by considering the results obtained

Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework

Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes

Engineering a Spin-Orbit Bandgap in Graphene-Tellurium Heterostructures

Intensive research has focused on harnessing the potential of graphene for electronic, optoelectronic, and spintronic devices by generating a bandgap at the Dirac point and enhancing the spin-orbit interaction in the graphene layer. Proximity to heavy p elements is a promising approach; however, their interaction in graphene heterostructures has not been as intensively studied as that of ferromagnetic, noble, or heavy d metals, neither as interlayers nor as substrates. In this study, the effective intercalation of Te atoms in a graphene on Ir(111) heterostructure is achieved. Combining techniques such as low energy electron diffraction and scanning tunneling microscopy, the structural evolution of the system as a function of the Te coverage is elucidated, uncovering up to two distinct phases. The presented angle-resolved photoemission spectroscopy analysis reveals the emergence of a bandgap of about 240 meV in the Dirac cone at room temperature, which preserves its characteristic linear dispersion. Furthermore, a pronounced n-doping effect induced by Te in the heterostructure is also observed, and remarkably the possibility of tuning the Dirac point energy towards the Fermi level by reducing the Te coverage while maintaining the open bandgap is demonstrated. Spin-resolved measurements unveil a non-planar chiral spin texture with significant splitting values for both in-plane and out-of-plane spin components. These experimental findings are consistent with the development of a quantum spin Hall phase, where a Te-enhanced intrinsic spin orbit coupling in graphene surpasses the Rashba one and promotes the opening of the spin-orbit bandgap.Comment: 9 pages, 4 figure