Debris Monitoring Research Articles

A Case Study in Planning and Executing a Source-Control Exercise Using a Visual Simulator as a Well Response Training Tool

ABSTRACT Since the 2010 Macondo incident, the oil industry has made many strides in improving offshore blowout prevention and preparedness. This includes manufacturing over 20 large subsea capping stacks with other supporting subsea source control equipment (e.g. cutting tools for debris removal, injection and monitoring equipment for subsea dispersants) , and routinely conducting emergency exercises to demonstrate the ability to simulate deploying their subsea control equipment defined in their source control emergency response plans, often on short notice for government initiated unannounced exercises. In 2017, Anadarko partnered with U.S. and Mexican government agencies to conduct a joint-preparedness exercise to demonstrate a binational response to a hypothetical pollution incident that would threaten the border zone of both countries. The exercise conduced in accordance with the Mexico – US (MEXUS) Plan, a bilateral agreement between both countries for offshore spill that would originate in one country and could impact the other country. Coordinating a drill that involved over 300 participants from multiple companies and organizations took several years. A short coming of previous similar exercises have been the lack of visualization and sense of realism. A fit-for-purpose visualization simulator was used improve the overall training and learning experience. The visual simulator is coupled with a dynamic multi-phase simulator to ensure that the physics of the blowout and intervention operations are as realistic as possible. The improved visualizations and physics of the source-control operation significantly improved the learnings compared to previous exercise events. This paper explains the general methodology for closing a capping stack, and, more importantly, the planning process that made the drill successful.

Recent Advances of the BIRALET System about Space Debris Detection

Space debris is internationally recognized as a planetary threat. Efforts to enhance the worldwide radar monitoring networks have been intensified in the last years. Among the new radars employed for the observations, one of the most promising is the Bistatic Radar for Low Earth Orbit (LEO) Tracking (BIRALET), which employs the Sardinia Radio Telescope as a receiving segment. The Sardinia Radio Telescope (SRT) has recently been proven to be a reliable instrument for space debris monitoring and, for this purpose, over the years has undergone some substantial modifications in order to be able to rise to the status of a fully functional radar receiver. However, an extensive measurement campaign, in order to assess the real potential of the radar, has never been done before. In this paper, the authors present the first real space debris measurement campaign of the SRT, made between December 2018 and October 2019 using the new dedicated channel of the P-band receiver. A total of 27 objects were correctly detected during this campaign, characterized by a radar cross section (RCS) interval between 0.13 and 13.4 m2 and a range interval between 459 and 1224 km.

Self-powered artificial joint wear debris sensor based on triboelectric nanogenerator

Replacing the diseased joints with artificial prostheses has long been a common medical mean to alleviate pain or disability, in which the wear debris-induced aseptic loosening is the main mechanism for failure of artificial joint replacement. Timely and in situ detection of the wear debris is necessary to prevent further deterioration of the joint, and provides a basis for the lifetime diagnosis of artificial joint. Here, a self-powered sensor based on triboelectric nanogenerator (TENG) was developed for detecting wear debris generated in artificial joint. The TENG with polyethylene film and steel ball was designed into artificial joint configuration and fabricated by thermo-compression, which could in-situ detect the production of wear debris. Furthermore, the dependence of electrical output signals on the amount and size of the debris was investigated, which demonstrated obvious decrease in voltage with the increase in the amount and size of the particles. Finally, the fabricated sensor was tested in joint wear simulator, which achieved the real-time wear debris monitoring. This work expands the application of TENG in artificial joint wear detection, which is expected to promote the development of biomedical sensor and intelligent healthcare.

Development of the First Portuguese Radar Tracking Sensor for Space Debris

Currently, space debris represents a threat for satellites and space-based operations, both in-orbit and during the launching process. The yearly increase in space debris represents a serious concern to major space agencies leading to the development of dedicated space programs to deal with this issue. Ground-based radars can detect Earth orbiting debris down to a few square centimeters and therefore constitute a major building block of a space debris monitoring system. New radar sensors are required in Europe to enhance capabilities and availability of its small radar network capable of tracking and surveying space objects and to respond to the debris increase expected from the New Space economy activities. This article presents ATLAS, a new tracking radar system for debris detection located in Portugal. It starts by an extensive technical description of all the system components followed by a study that estimates its future performance. A section dedicated to waveform design is also presented, since the system allows the usage of several types of pulse modulation schemes such as LFM and phase coded modulations while enabling the development and testing of more advanced ones. By presenting an architecture that is highly modular with fully digital signal processing, ATLAS establishes a platform for fast and easy development, research, and innovation. The system follows the use of Commercial-Off-The-Shelf technologies and Open Systems which is unique among current radar systems.

The Ad Hoc Back-End of the BIRALET Radar to Measure Slant-Range and Doppler Shift of Resident Space Objects

Space debris is a term for all human-made objects orbiting the Earth or reentering the atmosphere. The population of space debris is continuously growing and it represents a potential issue for active satellites and spacecraft. New collisions and fragmentation could exponentially increase the amount of debris and so the level of risk represented by these objects. The principal technique used for the debris monitoring, in the Low Earth Orbit (LEO) between 200 km and 2000 km of altitude, is based on radar systems. The BIRALET system represents one of the main Italian radars involved in resident space objects observations. It is a bi-static radar, which operates in the P-band at 410–415 MHz, that uses the Sardinia Radio Telescope as receiver. In this paper, a detailed description of the new ad hoc back-end developed for the BIRALET radar, with the aim to perform slant-range and Doppler shift measurements, is presented. The new system was successfully tested in several validation measurement campaigns, the results of which are reported and discussed.

Crowded Space: A Review on Radar Measurements for Space Debris Monitoring and Tracking

Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities.

A Novel Impedance Micro-Sensor for Metal Debris Monitoring of Hydraulic Oil

Hydraulic oil is the key medium for the normal operation of hydraulic machinery, which carries various wear debris. The information reflected by the wear debris can be used to predict the early failure of equipment and achieve predictive maintenance. In order to realize the real-time condition monitoring of hydraulic oil, an impedance debris sensor that can detect inductance and resistance parameters is designed and studied in this paper. The material and size of wear debris can be discriminated based on inductance-resistance detection method. Silicon steel strips and two rectangular channels are designed in the sensor. The silicon steel strips are used to enhance the magnetic field strength, and the double rectangular detection channels can make full use of the magnetic field distribution region, thereby improving the detection sensitivity and throughput of the sensor. The comparison experiment shows that the coils in series are more suitable for the monitoring of wear debris. By comparing and analyzing the direction and the presence or absence of the signal pulses, the debris sensor can detect and distinguish 46 µm iron particles and 110 µm copper particles. This impedance detection method provides a new technical support for the high-precision distinguishing measurement of metal debris. The sensor can not only be used for oil detection in the laboratory, but also can be made into portable oil detection device for machinery health monitoring.

An Ultrasensitive Debris Microsensor for Oil Health Monitoring Based on Resistance–Inductance Parameter

An ultrasensitive debris sensor based on microfluidic technology is introduced in this article. The microsensor not only achieves the traditional inductance detection, but also proposes a resistance detection method based on coil. The magnetic field distribution in the detection region was obtained by simulation, and the magnetization and eddy current effects of metal particles in harmonic magnetic field were simulated. The frequency characteristics and signal characteristics of inductance and resistance detection were studied through experiments. High-frequency excitation can enhance the eddy current effect inside the metal particles, thereby helping to improve the resistance detection sensitivity, enhance the inductance detection effect of nonferromagnetic metal particles, and reduce the inductance detection effect of ferromagnetic metal particles. The research results showed that inductance parameter has stronger detection ability for ferromagnetic metals, and resistance parameter has stronger detection ability for nonferromagnetic metals. According to the characteristics of inductance and resistance signals, the accurate distinction of metal debris property and size can be realized. And the size measurement error caused by the debris shape can be reduced by the judgment method based on two parameters. This impedance detection based on inductance and resistance parameters provides a new method for high-sensitivity monitoring of metal debris. The debris microsensor can be used as a sensing element of portable oil monitoring devices, and provide technical support for health assessment, state warning, and fault diagnosis of mechanical equipment.

Retrospective on the Problem of Space Debris. Part 2. Monitoring of Space Debris of Natural Origin in Near-Earth Space Using Optical Methods of Meteor Astronomy

A review of publications on the problems of monitoring of clogging near-Earth space by natural space debris, including hazardous meteoroids, using methods of optical meteor astronomy is carried out. Both observation methods and methods for estimating the danger from natural space debris for spacecraft are analyzed.

Многоапертурная оптическая система счета фотонов в изображении для безаберрационных наблюдений космического мусора через турбулентную атмосферу (Часть II)

The paper considers the principles of construction and application strategies of the ground optical system for space debris monitoring protected by the patent of the Russian Federation for the invention. The aim of this invention was to increase the diffraction resolution of the formed images of a small space object and improve the accuracy of restoration of the module undistorted by the atmosphere and phase of its spatial spectrum. To achieve this goal, formation of atmospherically distorted images of a space object is carried out by a coherent matrix of M moving telescopes of the diameter D in the process of space-time aperture synthesis, which directs the combined subbeams from moving telescopes along the tracks to the center of the matrix, where the stationary base is placed, which performs both coherent combination of subbeams and detection of formed series of N images with their subsequent registration and processing. During statistical processing of moduli and phases of spatial spectra of registered images, the island nature of the optical transfer function (OTF) of matrix along the ellipses of coherence and its semi-island in the radial direction extending from the center of the spatial frequency domain to the cutoff frequency of the synthesized aperture of the diameter Dэ is taken into account. The positive effect of using this invention is that the coherent operation of the matrix provides a gain in the diffraction resolution of Dэ/D times (Dэ/D 1), and an increase of D/r0 times, where r0 is the atmospheric fluctuations correlation radius, the accuracy of restoration of the undistorted by the atmosphere module and phase of the space spectrum from the object by the proposed smoothing procedure allows reducing by the same factor (D/r0 1) the required number of N registrations in series reducing the total monitoring time.

Многоапертурная оптическая система счета фотонов в изображении для безаберрационных наблюдений космического мусора через турбулентную атмосферу (Часть I)

The paper solves the problem of space debris monitoring to ensure the safety of space exploration. Space debris fragments are small-sized control objects with angular sizes up to 0.002 arcsecond. Therefore, optoelectronic systems of high resolution and permeability allowing one to measure the coordinates and recognize these weak control objects with a given accuracy and probability having integral brightness up to +18 stellar magnitude are necessary for the location (search, detection, measurement, and identification) of space debris fragments. To solve the optical location problems of space debris the Part I of the article proposes the concept of building a ground-based optoelectronic control system. The system consists of three consecutive and interrelated information channels: an image formation channel based on the matrix of individual telescopes and aperture synthesis technology; image detection channel based on scanning raster detectors and photon counting technology in the image; and image processing channel based on digital correlation compensation technology of atmospheric distortions. Advantages of a matrix of separate telescopes, photodetection and correlation processing are noted in the article. The proposed concept is protected by a patent of the Russian Federation, which is discussed in detail in Part II.

Method of forming a rational set of test trajectory options to increase the reliability of performance evaluation during testing of radar information tools

To get an objective picture of the state of near-earth space, it is necessary to update the fleet of information tools in a timely manner, which is characterized by the introduction of new tools and the modernization of old tools, while changing the system in stages as the funds are ready. The continuous build-up of the system's assets as they are ready allows us to improve its performance without waiting for all newly introduced and upgraded assets to be ready. To test monitoring systems in conditions of a large number of heterogeneous elements combined in a system to achieve a single goal, an experimental and theoretical method of evaluating effectiveness based on mathematical modeling is used. The essence of this method is to simulate information at the input of programs of the system tools using mathematical models implemented directly on the system tools themselves. In this case, the quality of test trajectories that would allow evaluating the characteristics of radar information tools and the capabilities of monitoring systems is of particular importance. The purpose of the study is to increase the reliability of the results of tests of radar information tools for monitoring space debris by selecting a rational set of trajectory options that allow for the worst possible implementation of the capabilities of radar information tools, taking into account the functioning of each specific radar information tool participating in the tests. Based on the features of the factor space for finding solutions to the problem of forming test trajectories, the algorithm for forming the initial population and the algorithm for generating a new generation should be supplemented with blocks for checking the observability and feasibility of trajectories. The developed method of forming a rational set of variants of test trajectories using genetic algorithms differs from the known ones in that it generates a set of variants of test trajectories optimized from the point of view of obtaining the worst implementations of the capabilities of radar systems during its testing, under conditions of restrictions on the feasibility and observability of trajectories, the application of the methodology allows automating the process of preparing initial data for testing space debris monitoring systems in order to evaluate their characteristics. The application of the developed method allows to obtain the maximum errors in determining the parameters of the trajectory of space debris elements.

A Highly Sensitive In-Line Oil Wear Debris Sensor Based on Passive Wireless LC Sensing

This paper presents ${a}$ new, and efficient, wear debris detection sensor based on passive wireless LC sensing approach. This sensor enables online monitoring of metal debris in hydraulic flow tubes with large thickness, employed in high-pressure applications. In conventional inductive debris sensors, the coil is kept outside the tube. $(i)$ Hence, for thick tubes, the sensitivity is extremely low. If the coil is kept inside the tube, holes are required to connect it to the measurement unit (MU). (ii) This limits the pressure withstanding capacity. The proposed sensor solves these two problems using the wireless LC sensor approach, wherein the MU is connected to an outer coil (outside the thick tube), and an inner coil is kept close to the oil, with debris. Thus, it is highly sensitive to the debris. It requires no electrical connection to the MU. The outer coil is energized from an AC signal at the parallel resonance frequency of the system, drawing minimum current from the source. The change in phase of this current, due to the change in inductance of the inner coil as debris passes, is measured using ${a}$ phase-sensitive detector. This highly sensitive measurement approach together with the fact that the inner coil is close to the oil, helps to achieve high sensitivity, and enables monitoring flow tubes with large diameter and thickness. ${A}$ prototype of the proposed wireless LC debris sensor has been developed (inner and outer diameters of 25.4 mm and 80 mm respectively), integrated into ${a}$ hydraulic circuit and tested. The output was not only very sensitive to ferrous and non-ferrous metallic particles but also helps in distinguishing them.

A global assessment of the relationship between anthropogenic debris on land and the seafloor

Pollution of coastal and marine environments by mismanaged anthropogenic debris is a global threat requiring complex, multilateral solutions and mitigation strategies. International efforts to catalogue and quantify the density, extent and nature of mismanaged waste have not yet assessed the heterogeneity of debris between nearby areas. Better understanding of how debris types and density can be used as a proxy between regions and between land and seafloor habitats at a global scale can aid in developing cost effective and representative debris monitoring systems. Using volunteer collected clean-up and survey data, we compared the proportion and density of both total debris and specific items across 19,428 coastal land and seafloor sites from International Coastal Cleanups and Dive Against Debris surveys, from 86 countries between 2011 and 2018. We show that although some items common on land are also common on the seafloor, there is an overall global mismatch between debris types and densities on land and the seafloor from nearby areas. Correlations in land/seafloor debris type/density occurred primarily for items which entangle and/or sink, including fishing line, plastic bags, glass and polyethylene terephthalate (PET) bottles. Minimal similarity between land and seafloor surveys occurs for items which float or degrade. We suggest that to accurately evaluate local debris density, land and seafloor surveys are required to gain a holistic understanding. When detailed information on debris type, relative concentration, and likely source and transport are assessed, more cost effective and efficient policy interventions can be designed and implemented from local through to global scales.

Methodology matters for comparing coarse wood and bark decay rates across tree species

Abstract The importance of wood decay for global carbon and nutrient cycles is widely recognized. However, relatively little is known about bark decay dynamics, even though bark represents up to 25% of stem dry mass. Moreover, bark presence versus absence can significantly alter wood decay rates. Therefore, it really matters for the fate of carbon whether variation in bark and wood decay rates is coordinated across tree species. Answering this question requires advances in methodology to measure both bark and wood mass loss accurately. Decay rates of large logs in the field are often quantified as loss in tissue density, in which case volume depletions of bark and wood can yield large underestimations. To quantify the real decay rates, we assessed bark mass loss per stem surface area and wood mass loss based on volume‐corrected density loss. We further defined the range of actual bark mass loss by considering bark cover loss. Then, we tested the correlation between bark and wood mass loss across 20 temperate tree species during 4 years of decomposition. The area‐based method generally showed more than 3‐fold higher bark mass loss than the density‐based method (even higher if considering bark cover loss), and volume‐corrected wood mass losses were 1.08–1.12 times higher than density‐based mass loss. The deviation of bark mass loss between the two methods was higher for tree species with thicker inner bark. Bark generally decomposed twice as fast as wood across species, and faster decaying bark came with faster decaying wood (R2 = 0.26, p = 0.006). We strongly suggest using corrected volume when assessing wood mass loss especially for the species with faster decomposable sapwood and all the wood at advanced decay stages. Further studies of coarse stem decomposition should consider trait ‘afterlife’ effects of inner bark and estimate fraction of stem bark cover to obtain more accurate decay rates. Our new method should benefit our understanding of the in situ dynamics of woody debris decay and monitoring research in different forest ecosystems world‐wide, and should aid meta‐analyses across diverse studies.

PyBIRALES: A Radar Data Processing Backend for the Real-Time Detection of Space Debris

The growing population of artificial satellites in near-Earth orbit has made the monitoring of orbital debris objects ever more important. Orbital debris objects pose a threat to these satellites as their orbit cannot be changed in order to avoid a collision. In recent years, the European Space Agency (ESA)’s Space Surveillance and Tracking (SST) programme has been assisting national institutions in the upgrading of their space debris detection and monitoring capabilities. One of the latest such systems within this programme is the BIRALES space surveillance system based in Italy. The receiving antenna is a radio telescope that is made up of 32 receivers which are placed on eight parabolic cylindrical reflectors of the North–South arm of the Istituto Nazionale di Astrofisica (INAF)’s Northern Cross. This work introduces a new software backend which was developed for this novel space debris sensor. The system was designed to be a fast, highly configurable software backend for the radio telescope’s acquisition and processing system and whose monitoring and control can be realized by a simple front-end web-based application. The real-time detection of Resident Space Object (RSO) is an important prerequisite for such a system as it gives the operator an immediate feedback loop on any detections whilst keeping the storage requirements at a minimum given that there is no need to save the raw data. The detection of high-velocity objects is achieved by means of a specially developed data processing pipeline that uses the received raw antenna voltages to generate a number of beams, collectively known as a multipixel, that cover the Field of View (FoV) of the instrument. The trajectory of the detected objects is determined by considering the illumination sequence within this multipixel. The initial results on known objects represent the first steps in extending the growing network of European SST systems.

Effectiveness analysis of the prediction of regional debris flow susceptibility in post-earthquake and drought site

Debris-flow disasters occurred frequently after the M-w 8.0 Wenchuan earthquake on 12 May 2008 in Sichuan Province, China. Based on historical accounts of debris-flow disaster events, it found that debris flow occurrence is closely related to the impact of earthquakes and droughts, because earthquake-drought activities can increase the loose solid materials, which can transform into debris flows under the effect of rainstorms. Based on the analysis of historical earthquake activity (frequency, magnitude and location), drought indexes and the trend of climate change (amount of rainfall), a prediction method was established, and the regional debris flow susceptibility was predicted. Furthermore, in a debris flow-susceptible site, effective warning and monitoring are essential not only from an economic point of view but are also considered as a frontline approach to alleviate hazards. The advantages of the prediction and early monitoring include (1) the acquired results being sent to the central government for policy making; (2) lives and property in mountainous areas can be protected, such as the 570 residents in the Aizi valley, who evacuated successfully before debris flows in 2012; (3) guiding the government to identify the areas of disasters and the preparation for disaster prevention and mitigation, such as predicting disasters in high-risk areas in the period 2012-2017, helping the government to recognize the development trend of disasters; (4) the quantitative prediction of regional debris-flow susceptibility, such as after the Wenchuan earthquake, can promote scientific and sustainable development and socioeconomic planning in earthquake-struck areas.

Проблемы оптического мониторинга космического мусора

Проблемы оптического мониторинга космического мусора

Design of information management system for structural monitoring based on network fragmentation

Aiming at the shortcomings of current information management system, such as low security, poor economy and long response time, a design method of structure monitoring information management system based on network fragments is proposed. Firstly, the overall architecture of the network debris structure monitoring information management system is designed and the requirements of the monitoring information management system are analysed. Then, based on the analysis of the main characteristics of the network debris monitoring information management system, the modules and subsystems of the system are designed separately, and the system data management scheme is given. In this way, the design of structured monitoring information management system based on network fragments is completed. The experimental results show that the information management system can manage the network information safely and economically. The response time is short, and the overall performance of the structured monitoring information management system is improved.

Design of information management system for structural monitoring based on network fragmentation

Aiming at the shortcomings of current information management system, such as low security, poor economy and long response time, a design method of structure monitoring information management system based on network fragments is proposed. Firstly, the overall architecture of the network debris structure monitoring information management system is designed and the requirements of the monitoring information management system are analysed. Then, based on the analysis of the main characteristics of the network debris monitoring information management system, the modules and subsystems of the system are designed separately, and the system data management scheme is given. In this way, the design of structured monitoring information management system based on network fragments is completed. The experimental results show that the information management system can manage the network information safely and economically. The response time is short, and the overall performance of the structured monitoring information management system is improved.