Large Experimental Facilities Research Articles

FishSeg: 3D Fish Tracking Using Mask R-CNN in Large Ethohydraulic Flumes

To study the fish behavioral response to up- and downstream fish passage structures, live-fish tests are conducted in large flumes in various laboratories around the world. The use of multiple fisheye cameras to cover the full width and length of a flume, low color contrast between fish and flume bottom and non-uniform illumination leading to fish shadows, air bubbles wrongly identified as fish as well as fish being partially hidden behind each other are the main challenges for video-based fish tracking. This study improves an existing open-source fish tracking code to better address these issues by using a modified Mask Regional-Convolutional Neural Network (Mask R-CNN) as a tracking method. The developed workflow, FishSeg, consists of four parts: (1) stereo camera calibration, (2) background subtraction, (3) multi-fish tracking using Mask R-CNN, and (4) 3D conversion to flume coordinates. The Mask R-CNN model was trained and validated with datasets manually annotated from background subtracted videos from the live-fish tests. Brown trout and European eel were selected as target fish species to evaluate the performance of FishSeg with different types of body shapes and sizes. Comparison with the previous method illustrates that the tracks generated by FishSeg are about three times more continuous with higher accuracy. Furthermore, the code runs more stable since fish shadows and air bubbles are not misidentified as fish. The trout and eel models produced from FishSeg have mean Average Precisions (mAPs) of 0.837 and 0.876, respectively. Comparisons of mAPs with other R-CNN-based models show the reliability of FishSeg with a small training dataset. FishSeg is a ready-to-use open-source code for tracking any fish species with similar body shapes as trout and eel, and further fish shapes can be added with moderate effort. The generated fish tracks allow researchers to analyze the fish behavior in detail, even in large experimental facilities.

ATHENA Main Heat Exchanger Conceptual Design and Thermal-Hydraulic Assessment With RELAP5 Code

Abstract Among the envisaged experimental infrastructures supporting ALFRED reactor development, Fostering Alfred Construction consortium identified ATHENA as one of the facilities to address the pool thermal-hydraulic challenges and demonstrate the feasibility of the revised ALFRED configuration, along with the thermal-hydraulic performances of its main components. ATHENA is a large pool-type lead-cooled multipurpose experimental facility featuring a large size vessel (3.2 m diameter, 10 m in height), conceived to host almost 800 tons of lead to test ALFRED relevant scaled components. The test section to be installed in the main vessel includes an electrically heated core simulator (CS), made of 7 FAs, which delivers to the primary coolant a nominal thermal power of 2210 kW, a main coolant pump for lead circulation, and a countercurrent shell and tubes main heat exchanger, which tube bundle is fed by pressurized water by a dedicated secondary circuit. A preliminary analytical calculation has been performed to identify the most suitable configuration for the ATHENA heat exchanger, as well as to achieve a preliminary sizing of the component. The final layout foresees a bundle of 91 bayonet tubes, arranged in a cylindrical geometry, having an active length of 3000 mm and adopting an external double wall tube with a pressurized helium gap. A numerical model of the heat exchanger has been developed using the thermal-hydraulic system code RELAP5/Mod3.3, and a numerical sensitivity analysis on the geometrical and operating parameters has been carried out to verify the performances of the component.

Thermal-Hydraulic Characterization and Numerical Modeling with RELAP5 Code of ATHENA Secondary Loop

Among the envisaged experimental infrastructures supporting Advanced Lead Fast Reactor European Demonstrator (ALFRED) reactor development, the FALCON [Fostering ALfred CONstruction] consortium identified the Advanced Thermo-Hydraulics Experiment for Nuclear Application (ATHENA) as one of the facilities to address the pool of thermal-hydraulic challenges and demonstrate the feasibility of the revised ALFRED configuration, along with the thermal-hydraulic performances of its main components. ATHENA is a large pool-type lead-cooled multipurpose experimental facility featuring a large-sized vessel (3.2-m diameter and 10-m height), conceived to host almost 800 tons of lead to test ALFRED-relevant scaled components. The test section to be installed in the main vessel includes an electrically heated core simulator, made of seven fuel assemblies, which delivers to the primary coolant a nominal thermal power of 2210 kW; a main coolant pump for lead circulation; and a countercurrent shell-and-tube main heat exchanger, of which the tube bundle is fed by pressurized water by a dedicated secondary circuit. This work presents the numerical model of ATHENA along with thermal-hydraulic characterization of the facility using the system code RELAP5/Mod3.3, properly modified to include the thermophysical properties of heavy liquid metals. After the characterization of the steady state representative of the Stage 3 foreseen for the ALFRED staged approach, results of a numerical sensitivity analysis aimed at defining the most suitable procedure for the shutdown transient of the facility are presented.

Fusion power supply advances by the J-TEXT engineering team

To meet the stringent requirements of the fusion power supply for large-scale fusion devices, the J-TEXT engineering team has carried out key technology research and applications in several important directions of fusion power supply. This article presents the advances made by the J-TEXT engineering team in recent years in the following areas: (1) a high-voltage power supply for an auxiliary heating system; (2) a breakdown protection device for an auxiliary heating power supply; (3) magnetic field compatibility; (4) a high-voltage pulsed power supply for a field-reversed configuration; (5) a large physics experimental facility control system. The research backgrounds, technical progress, test results, applications, summaries and prospects are described in detail in each part. These innovative research results and valuable engineering experience can promote the progress of fusion power supply technology, and also lay a foundation for the development of power supplies with higher parameters in the future.

Numerical study of synthetic spherically expanding flames for optimization of laminar flame speed experiments

This study presents the performances of four commonly-used extrapolation models, including the linear stretch and linear curvature models, the nonlinear model in expansion form, and the nonlinear quasi-steady model, using synthetic data sets generated over a wide range of conditions. The effects of a number of experimental limitations, such as the facility size, the finite camera framing rate, and the noise in the image detected flame radius, were investigated. Two types of error, model and noise error, which constitute the overall extrapolation uncertainty were investigated. Relative model error is primarily driven by Markstein length (Lb) and the flame radius range; however, it is weakly sensitive to laminar flame speed (Sb0). Noise error is controlled by the size of flame radius data set which depends on framing rate and the selected flame radius range. For small values of |Lb|, the model error is negligible. For large values of |Lb|, the two error types are equally prevalent in the overall uncertainty and they cannot be simultaneously minimized. Experimentally, large experimental facilities and high camera framing rates should be favored to reduce the noise error. For extrapolation to zero-stretch, the model that best reproduces the flame propagation evolution should be favored. The Markstein length demonstrates a high sensitivity to the choice of model and noise addition when compared to the laminar flame speed. The procedures developed in this study can be used to predict extrapolation-induced error under various experimental conditions and can be used to optimize laminar flame speed experiments.

Combining grazing incidence X-rays and micro-diffraction for qualitative phase identification in forensic powdered micro-samples

Capillary diffraction or microdiffraction are standard techniques for characterizing small samples when only a few milligrams are available. On the other hand, we have typical grazing incidence diffraction or different variations of grazing incidence (GI) diffraction used, such as in-plane grazing incidence (IP-GI) or GI using a micro focusing source, to study thin films. However, when few powder micrograms are available, the characterization task is complicated. In the present work, few micrograms of typical forensic samples are analyzed using standard Bragg-Brentano, X-ray powder diffraction geometry, and grazing incidence X-ray micro-diffraction (GIµXRD). Samples include soils, cosmetic eyeshadows, two different pyrotechnic materials, and a highly explosive mixture contained at primer cup of ammunition. The analysis was carried out from 1 to 5 degrees of the incident parallel beam with a shaking sample. Depending on the fixed incident angle, different small regions of the diffraction patterns showed an improvement in the intensity of the peaks with respect to the conventional Bragg-Brentano configuration. However, 3–5 degrees of the fixed incident beam showed the best results. This new data acquisition technique, based on the combination of two known diffraction methods, could be a powerful tool for studying samples outside of forensic sciences such as nanomaterials, medicine, or any other field where the sample quantity is extremely small, also, without the need to transport evidence and travel to external facilities with higher analytical performance such as synchrotron radiation installations or other large experimental facilities.

Gaussian processes for autonomous data acquisition at large-scale synchrotron and neutron facilities

The execution and analysis of complex experiments are challenged by the vast dimensionality of the underlying parameter spaces. Although an increase in data-acquisition rates should allow broader querying of the parameter space, the complexity of experiments and the subtle dependence of the model function on input parameters remains daunting owing to the sheer number of variables. New strategies for autonomous data acquisition are being developed, with one promising direction being the use of Gaussian process regression (GPR). GPR is a quick, non-parametric and robust approximation and uncertainty quantification method that can be applied directly to autonomous data acquisition. We review GPR-driven autonomous experimentation and illustrate its functionality using real-world examples from large experimental facilities in the USA and France. We introduce the basics of a GPR-driven autonomous loop with a focus on Gaussian processes, and then shift the focus to the infrastructure that needs to be built around GPR to create a closed loop. Finally, the case studies we discuss show that Gaussian-process-based autonomous data acquisition is a widely applicable method that can facilitate the optimal use of instruments and facilities by enabling the efficient acquisition of high-value datasets. Gaussian process regression (GPR) is a powerful, non-parametric and robust technique for uncertainty quantification and function approximation that can be applied to optimal and autonomous data acquisition. This Review introduces the basics of GPR and discusses several use cases from different fields.

Development of electronic record-keeping software for remote participation in Large Volume Plasma Device upgrade using Angular 2 and NodeJS web technologies.

In an era of digital transformation and collaborations, the Web Information System (WIS) becomes an essential requirement for the information and data sharing of large experimental facilities among users. With the enhancement in the capabilities and performance of web technologies, sharing of experimental data using a flexible, modular, secure, and robust mechanism is feasible. In this direction, the Large Volume Plasma Device (LVPD), an experimental device dedicated for carrying out investigations for unfolding physical phenomena of relevance to Earth's magnetosphere and fusion plasmas, also adopts web-based electronic record keeping for its operation. The nature of investigations is concerned with plasma turbulence of electron scale, induced anomalous plasma transport and mitigation of energetic electrons by excited whistler turbulence that requires large scale, and simultaneous multiple point measurements from different electrostatic and electro-magnetic diagnostics. This paper discusses the WIS implementation in LVPD for the experimental configuration, information logging, and preliminary data analysis. The architecture of the system is spread over three tiers covering application, data, and presentation layers. The presentation layer is developed using the Angular 2 framework on the progressive web application architecture. The application and data layers are developed using NodeJS and PostgreSQL, respectively. The novelty of this paper lies in the integrated application development approach and applicability of the latest web technologies in the scientific and experimental domains. This paper discusses the literature survey of similar developments at other places, requirements, scopes, development artifacts, adapted tools and technologies, obtained results from actual plasma discharges of LVPD, and future enhancements.

Развитие генетико-селекционных методов повышения продуктивности лесов

Представлена история становления института и основные направления работ ВНИИЛГИСбиотех за 50 лет научной и производственной деятельности. Основное внимание уделено инновационным разработкам и перспективам развития института. The article presents the history of the All-Russian Research Institute of Forest Genetics, Breeding and Biotechnology, the principal directions of its activity through over 50 years of scientific and production work. It focuses on innovations and the development perspective of the Institute. The Institute’s priority research areas are forest genetics and biotechnology. The Institute scientists were among the first in Russia to conduct research on the tissue culture methods for the plants genetic diversity and their future genetic improvement. The Institute has developed clonal micropropagation techniques for valuable tree biotypes, they have been put into forestry practice and are now 18 – 26 years old. Also, the Institute has developed the long-term in vitro storage method with the use of hormone-free nutrient solutions for valuable deciduous tree species. Based on this method, in 1991 our scientists began to create the collection of deciduous tree plants, which currently includes more than 70 clones of valuable, resistant, and fast-growing birch, poplar, aspen and willow genotypes. Throughout its existence the Institute has established a large experimental facility which includes seed plantations of Scots pine, pedunculate oak and other species. All experimental units are being closely monitored. Through over 50 years of scientific work we have developed the multi-year breeding program, selected the economically valuable clones and forms, obtained and patented new varieties of tree species. Our scientists are now focused on obtaining new genotypes of forest trees, increasing productivity and selective value of the main forest-forming species, studying their ecological and genetic parameters, creating new breeding facilities, conserving the plant genetic resources, etc.

On Automatic Reconnects in the Control Systems of Large Experimental Facilities

All modern control systems (CS’s) of large experimental facilities are distributed. Nodes are connected via Ethernet or via specific links such as CAN, RS232/485, GPIB, etc. During normal operation, all nodes are online and connections between them are established and work. However, during operation some nodes can become unavailable for various reasons: electronic failure, power-supply failure, communication line break, human error, etc. Therefore, the task of restoring connections between nodes arises (after the problems are solved). In this paper, the implementation of automatic reconnects in various situations is discussed based on the experience of the VEPP-5 Injection Complex CS at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences.

Investigation of the Transient Field at High Velocities by magnetic-moment measurements in 74Ge and 70Zn

The advent of radioactive beams at large experimental facilities has moti- vated extensive research work on the expansion of techniques to accommodate higher ion velocities. The application of the Transient Field technique in measuring magnetic moments of excited states in energetic nuclei is investigated at the INFN-LNS in Catania by means of re-measuring the g(2+1 ) factors in 74Ge and 70Zn. The description of the experiment method and some preliminary angular correlation results are presented.

ИССЛЕДОВАНИЕ МЕХАНИЗМОВ ГЕНЕРАЦИИ МОРСКИХ БРЫЗГ ПРИ СИЛЬНЫХ ВЕТРАХ И ИХ РОЛИ В МЕХАНИКЕ И ТЕРМОДИНАМИКЕ УРАГАНОВ

In storm conditions, the atmosphere and the ocean are multiphase: the boundary layer of the atmosphere is saturated with splashes and raindrops, foamy areas are present on the surface of the water, and the near-surface water layer is saturated with air bubbles. This causes radical changes in the ocean-atmosphere exchange processes that must be taken into account when constructing models. Empirical data on the parameters of such media, obtained under natural conditions, are characterized by large errors. Laboratory modeling on large experimental facilities helps to reduce this uncertainty. In this regard, modern laboratory facilities for modeling hurricane wind conditions have been created in the USA and Japan. This article presents the results of recent studies of multiphase media at the Unique Scientific Installation “Complex of large-scale geophysical stands” of the IAP RAS.

A Dynamic Programmable Network for Large-Scale Scientific Data Transfer Using AmoebaNet

Large scientific experimental facilities currently are generating a tremendous amount of data. In recent years, the significant growth of scientific data analysis has been observed across scientific research centers. Scientific experimental facilities are producing an unprecedented amount of data and facing new challenges to transfer the large data sets across multi continents. In particular, these days the data transfer is playing an important role in new scientific discoveries. The performance of distributed scientific environment is highly dependent on high-performance, adaptive, and robust network service infrastructures. To support large scale data transfer for extreme-scale distributed science, there is the need of high performance, scalable, end-to-end, and programmable networks that enable scientific applications to use the networks efficiently. We worked on the AmoebaNet solution to address the problems of a dynamic programmable network for bulk data transfer in extreme-scale distributed science environments. A major goal of the AmoebaNet project is to apply software-defined networking (SDN) technology to provide “Application-aware” network to facilitate bulk data transfer. We have prototyped AmoebaNet’s SDN-enabled network service that allows application to dynamically program the networks at run-time for bulk data transfers. In this paper, we evaluated AmoebaNet solution with real world test cases and shown that how it efficiently and dynamically can use the networks for bulk data transfer in large-scale scientific environments.

Accelerating small-angle scattering experiments on anisotropic samples using kernel density estimation

We propose a method to accelerate small-angle scattering experiments by exploiting spatial correlation in two-dimensional data. We applied kernel density estimation to the average of a hundred short scans and evaluated noise reduction effects of kernel density estimation (smoothing). Although there is no advantage of using smoothing for isotropic data due to the powerful noise reduction effect of radial averaging, smoothing with a statistically and physically appropriate kernel can shorten measurement time by less than half to obtain sector averages with comparable statistical quality to that of sector averages without smoothing. This benefit will encourage researchers not to use full radial average on anisotropic data sacrificing anisotropy for statistical quality. We also confirmed that statistically reasonable estimation of measurement time is feasible on site by evaluating how intensity variances improve with accumulating counts. The noise reduction effect of smoothing will bring benefits to a wide range of applications from efficient use of beamtime at laboratories and large experimental facilities to stroboscopic measurements suffering low statistical quality.

Application of ground vibration measurement in large experimental facilities based on spectrum estimation methods

Application of ground vibration measurement in large experimental facilities based on spectrum estimation methods

The Ecological Society of America at Mid‐Century: Finding Its Voice

The Ecological Society of America at Mid‐Century: Finding Its Voice

The earthing system of the PRIMA Neutral Beam Test Facility based on the Mesh Common Bonding Network topology

PRIMA is a large experimental facility under realization in Padova, aimed at developing and testing the Neutral Beam Injectors for ITER. The operation of these devices involves high RF power and voltage up to 1MV. Frequent and high voltage electrical breakdowns inside the beam sources occur regularly. The presence of a distributed carefully optimized earthing system is of paramount importance to achieve a satisfying disturbances immunity for equipment and diagnostics.The paper describes the design and the realization of the earthing system of the PRIMA facility, which is based on the MESH-Common Bonding Network (MESH-CBN) topology, as recommended by IEC and IEEE standards for installations with high levels of Electromagnetic Interferences (EMI). The principles of the MESH-CBN approach were adapted to the PRIMA layout, which is composed by several buildings, that are independent for seismic and architectural reasons, but are linked by many electrical conduits and hydraulic pipelines. The availability of huge foundations, with a large number of poles and pillars, was taken into account; building parts dedicated to host control rooms and sensitive equipment were treated with particular care. Moreover, the lightning protection system was integrated and harmonized with the earthing system.

Experimental study of a remote sealing method for vacuum leak

Vacuum leak is a critical issue for all devices having vacuum system, especially for the large complex experimental facilities. They often have vacuum components integrated which are inaccessible once the assembly was finished. Therefore, if any unacceptable vacuum leaks occur on the cooling/baking channels of the vacuum components, the machine, at least partially, needs to be disassembled before the maintenance, which would cause extensive experimental program downtime and financial costs. An innovative remote sealing method has been studied to permanently repair such vacuum leaks by injecting a sealant called KH-1714 into the channels with pressurized inert gas. Three experiments, that at 10–20 m away sealing different types of leaked components (bellows, circular pipe or rectangle pipe) with leak rates at the level of 10−6–10−5 Pa m3/s, were done to study the feasibility and reliability of the method. The details of the experiments and results were presented and discussed.

Influence of jet aeration on pressures around a block embedded in a plunge pool bottom

The influence of the air entrained by water jets on the dynamic pressures applied on the bottom of a plunge pool and inside underlying fissures was analyzed with systematic experiments. The large experimental facility reproduced aerated high-velocity jets up to 22.1 m/s impinging on a pool and impacting on an instrumented cubic block embedded on the bottom. Plunging and submerged jets are compared, as well as jet impingement on the center or on the side of the block. A relationship is proposed to describe the time-averaged pressures at stagnation as a function of the relative pool depth, considering pressure measurements in this position as well as recent experimental evidence on the jet centerline velocity decay. Air bubbles influence the dynamic pressures on the rock bottom by reducing jet momentum, but also by reducing the jet dissipation rates in the water pool. These two processes are opposed. The reduction of momentum, consequence of a jet with a lower apparent density, results in lower pressures, while lower jet dissipation in the pool results in higher kinetic energy of the jet impacting the bottom and higher pressures. Finally, the spectral contents show that the resonance frequencies of aerated jets are shifted as a consequence of wave celerity reduction caused by lower mean densities inside the fissures, which is an evidence of the presence of air bubbles.

実験室X 線を用いたCoated conductor の超伝導部の直接評価

Recently, quantum beams such as neutrons or X-rays of synchrotron radiation are being used to measure the internal strain of practical superconducting wires. These quantum beams can observe the superconducting materials in practical wires directly. The neutron and X-ray diffractions are useful methods for observing the internal strains in various practical superconducting wires. However, large experimental facilities must be visited in order to use neutron or synchrotron radiation. If it is possible to evaluate superconducting materials in practical wires at our own laboratory, it would be very useful. In this paper, I discuss the possibility of the internal strain evaluation of coated conductors using laboratory X-rays. The experiment of measuring the internal strain of a coated conductor was performed using Mo Kα. The diffraction peaks from a GdBCO in the coated conductor were observed. The behavior of the internal strain of a GdBCO in the coated conductor under tensile strain was estimated using laboratory X-rays. I found that this experimental technique is very useful for evaluating the internal strain of coated conductors and other thin superconducting tapes.