Series Of Experimental Campaigns Research Articles

Work break scheduling using wrist wearable devices: a conceptual and practical model

In recent years, the use of wearable devices, designed for monitoring the psycho-physical state of the user over time, has undergone a growing trend in the industrial field. The ability to monitor parameters, such as heart rate, electroencephalography, and motion activity, allows the identification of different states of the operator, such as stress, physical fatigue, or the level of attention. Therefore, these devices have the potential for use in working environments. This study investigated the possibility of using wearable wrist devices for optimal management of work breaks. Thanks to the monitoring of the operator's status in terms of heart rate, number of steps, and time, the scheduling of work breaks can be based on the real physiological needs of the operators rather than a fixed schedule. A preliminary conceptual and practical model was developed, and a series of experimental campaigns were presented to illustrate its functioning and potentialities.

14 MeV NEUTRON IRRADIATION EXPERIMENTS - GAMMA SPECTROSCOPY ANALYSIS AND VALIDATION AUTOMATION

An important area of research required for fusion reactor design is the study of materials under high energy neutron irradiation. Deuterium-Tritium (D-T) reactions release 14.1 MeV neutrons and material studies of such high energy neutrons focusing on transmutation and activation are paramount for fusion tokamak devices such as ITER and DEMO. In order to understand neutron damage and transmutation-induced radioactivity in fusion regime energies, a series of experimental campaigns were performed at the ASP facility based at Aldermaston in the UK, which uses a deuteron accelerator to bombard a tritiumloaded target and generate 14 MeV-neutron emission rates of up to 2.5 × 1011 s−1. In this work, a holistic treatment of the 11,000 gamma spectra (time series data) collected over five experimental campaigns is applied to identify radioisotopes and validate nuclear data and the inventory code, FISPACT-II. Whilst previous analysis has examined single spectra and foil irradiation’s using traditional, human-driven methods, this work applies novel methods using Artificial Neural Networks (ANN) and classification algorithms to allow a fully automated approach. Using such methods we show good broad agreement with FISPACT-II inventory simulations, and an overview of results are given as C/E values.

Size Dependence and Dynamic Properties of Adobe Masonry Bricks tested at high strain rates

Masonry is a construction technique which typically reacts in compression. Characterization of its material properties in compression is thus of paramount importance. This especially counts for adobe bricks because their material properties are still unknown to a large extent. This traditional masonry, made of locally available soil and fibres, is spread in areas currently involved in military conflicts, where also European forces operate. Therefore, not only its static properties in compression, but even more the dynamic strength is a relevant parameter. Laboratory characterization of material properties still pose several challenges, among which so-called size dependence is one of the most controversial topics. This entails the possible variation of material properties values from tests on specimens of different size and shape. Several factors may concur to its determination and a well-founded theory does not exist yet. This counts for statics and even more in dynamics. Addressing the properties in compression of bricks at high strain rates is rare, namely no studies of size dependence on masonry bricks in dynamic regimes are published. Lately, a series of experimental campaigns were conducted by the authors at the Joint Research Centre of the European Commission. In these campaigns, a series of compression tests were performed on several types of adobe bricks. Different soil mixtures were used to produce cylindrical samples of different sizes. Compressive tests from 2e-5 s-1 to 10 s-1 and 100 s-2 were executed using hydraulic machines as well as split Hopkinson bars. Next, the static as well as the dynamic material properties as calculated from tests on specimens of different sizes and material compositions have been qualitatively and quantitatively compared and interpreted. In this paper, the experimental program is presented, next the material properties in strength and ductility as well as the dynamic increase factors are investigated.

Self-excitation in a helical liquid metal flow: the Riga dynamo experiments

The homogeneous dynamo effect is at the root of magnetic field generation in cosmic bodies, including planets, stars and galaxies. While the underlying theory had increasingly flourished since the middle of the 20th century, hydromagnetic dynamos were not realized in the laboratory until 1999. On 11 November 1999, this situation changed with the first observation of a kinematic dynamo in the Riga experiment. Since that time, a series of experimental campaigns has provided a wealth of data on the kinematic and the saturated regime. This paper is intended to give a comprehensive survey about these experiments, to summarize their main results and to compare them with numerical simulations.

Trombe wall management in summer conditions: An experimental study

The application of Trombe walls in temperate climates is problematic due to undesired heat gains and overheating phenomena in summer. A proper shading and ventilation of this system can reduce such drawbacks, but the impact of these strategies on the wall’s thermal parameters is yet not widely investigated in quantitative terms.This paper presents an experimental study on the thermal behavior of Trombe walls in summer under Mediterranean climate conditions. The aim of the study is to determine experimentally the thermal parameters of a Trombe wall in summer conditions through the changing of shading, ventilation and operational conditions.In order to do that a series of experimental campaigns were carried out on a case study. A detailed simultaneous monitoring of two Trombe walls made it possible to compare the thermal behavior by varying the screening, ventilation and internal gains conditions. Furthermore, monitoring of indoor thermal comfort conditions and energy simulation using a model in dynamic state were carried out. The results showed that shading, ventilation and occupancy conditions affect significantly the thermal parameters of Trombe wall in summer: screening with roller shutters determines a decrease in internal surface temperature of the wall of 1.4°C and a decrease in daily heat gains of about 0.5MJ/m2; the combined use of overhangs, roller shutters and cross ventilation for the Trombe wall can assure a satisfactory thermal comfort level in summer and a reduction of the cooling energy needs respectively of −72.9% and −63.0% for a dwelling with low or highly insulated building envelope in comparison with the case of an unvented Trombe wall without solar protections.

Recent diagnostic developments on LHD

The recent diagnostic developments on the large helical device (LHD) are described briefly. LHD is the largest helical machine with all superconducting coils, and its purpose is to prove the ability of a helical system to confine a fusion-relevant plasma in steady state. According to the missions of LHD research, the diagnostic devices are categorized as follows: diagnostics for (i) high nτET plasmas and transport physics; (ii) magnetohydrodynamic stability; (iii) long pulse operation and divertor function; and (iv) energetic particles. These are briefly described focusing on the recent developments of the devices. Since the LHD experiment started in March 1998, five series of experimental campaigns have been carried out. The LHD diagnostics during these periods were operated successfully, and contributed to the analysis of the experimental results.

The application of X-ray imaging to the developments of fluidized bed processes

This paper reports some of the results obtained from a series of experimental campaigns, carried out over several years, aimed at visualizing the flow patterns occurring inside large-scale fluidized beds by applying an X-ray imaging technique. For over 12 years, BP has been developing and applying an X-ray imaging technique as part of its research and development programmes for both Oil and Chemicals technologies. This paper illustrates how BP has used the X-ray technique to identify some important process issues, in particular how factors like process designs and operating conditions like temperature, pressure and gas velocity influence the fluidization behaviour. Examples taken from BP Chemicals Gas Phase High Productivity (INNOVENE) technology are discussed, and the synergies with Fluid Catalytic Cracking (FCC) spray nozzle technology are highlighted. Within an FCC unit, this technique has been extensively applied to the catalyst and gas interactions within the regenerator and stripper vessels, and to air, steam and feed nozzle evaluations.

Implosion dynamics of long-pulse wire array Z pinches

Recent improvements in Z-pinch wire array load design at Sandia National Laboratories have led to a substantial increase in pinch performance as measured by radiated powers of up to 280 TW in 4 ns and 1.8 MJ of total radiated energy. Next generation, higher-current machines will allow for larger mass arrays and comparable or higher velocity implosions to be reached, possibly extending these results. As the current is pushed above 20 MA, a conventional machine design based on a 100 ns implosion time results in higher voltages, hence higher cost and power flow risk. Another approach, which shifts the risk to the load configuration, is to increase the implosion time to minimize the voltage. This approach is being investigated in a series of experimental campaigns on the Saturn [C. Deeney et al., Phys. Plasmas 6, 3576 (1999)] and Z [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998)] machines. In this paper, both experimental and two-dimensional computational modeling of the first long implosion time Z experiments will be presented. The experimental data shows broader pulses, lower powers, and larger pinch diameters compared to the corresponding short pulse data. By employing a nested array configuration, the pinch diameter was reduced by 50% with a corresponding increase in power of >30%. Numerical simulations suggest that load velocity is the dominating mechanism behind these results.

Characterization of wall conditions in DIII-D

Wall conditioning in DIII-D is one of the most important factors in achieving reproducible high confinement discharges. For example, the very high confinement mode (VH-mode) was only discovered after boronization, a chemical vapor deposition technique to deposit a thin boron film over the entire surface of the tokamak. In order to evaluate wall conditions and provide a data base to correlate these wall conditions with tokamak discharge performance, a series of nominally identical reference VH-mode discharges (1.6 MA, 2.1 T, double null diverted) were taken at various times during a series of experimental campaigns with evolving wall conditions. These reference discharges have allowed a quantitative determination of how the wall conditions have evolved. For instance, core carbon and oxygen levels in the VH-mode phase remained at historically low levels during the 1995 run year and there was also a steady decrease in the oxygen levels at plasma initiation during this period. We will discuss the long term changes in low Z impurities and the effect of wall conditioning techniques such as boronization and baking on these impurities. In addition, the evolution of the deuterium recycling rates will be discussed.