Preliminary development and testing of an open-path hydrocarbon sensor for oil and gas facility monitoring

2019 Summer.Includes bibliographical references.We developed an open-path laser absorption sensor for detection of unspeciated hydrocarbons for oil and gas production facility fence line monitoring. Such sensors can aid in maintaining air quality standards by quantifying greenhouse gas emissions and detecting emissions that cause adverse health effects. Our initial design employs a single-path detection system, though future implementations may use multiple paths for large-scale facility monitoring. The sensor uses a compact mid-infrared laser source in the spectral region of ~3.3 µm to measure absorption of several hydrocarbon species and is intended for open-paths of ~100 m to 1 km. Spectral simulations show that for typical conditions the hydrocarbons cause a transmission reduction of ~10% allowing for a robust measurement. The initial prototype system uses a helium-neon (He:Ne) laser at 3.391 µm for which signal contributions from methane and non-methane hydrocarbons are comparable. Closed-cell tests were performed with diluted methane (~150-250 ppm) to validate the transmission signals and showed good agreement with expected (calculated) values to within ~10%. The system employs a reference leg, with a 2nd detector (near the source), to normalize for laser power fluctuations. For improved signal-to-noise, particularly for detection of small concentrations and transmission changes, we employ phase-sensitive detection with a mechanical chopper and software based lock-in amplifier. This detection scheme, when employed in the field, allows measurement of transmission signals with stability <0.5% (based on coefficient of variation over 60 s). The portable field sensor system uses two refractive telescopes (2" diameter optics), a transmitter and receiver co-located on a mobile optical breadboard, and a reflector dictating the pathlength. We performed initial tests with pathlengths up to ~25 m (one way), though the design should allow paths in excess of 100 m. Methane was released for initial field tests at known flow rates near the center of the beam path. Transmission signals in agreement with expectations (given uncertainties in the wind and plume dispersion) were observed. The system should allow detection of leaks (emissions) for mass flows as low as ~0.1 g/s of methane (or equivalent optical signal from other species resulting in a 1% change in signal) for the case where the source is ~150 m from the beam path and under typical atmospheric conditions. Recommendations for future modifications are provided based on potential shortcomings identified by initial field testing. Initial field testing also proved that this technology could be a viable low-cost solution for hydrocarbon detection

Application of Power Electronics Converters in Smart Grids and Renewable Energy Systems

This book focuses on the applications of Power Electronics Converters in smart grids and renewable energy systems. The topics covered include methods to CO2 emission control, schemes for electric vehicle charging, reliable renewable energy forecasting methods, and various power electronics converters. The converters include the quasi neutral point clamped inverter, MPPT algorithms, the bidirectional DC-DC converter, and the push–pull converter with a fuzzy logic controller

Ultra low power wearable sleep diagnostic systems

Sleep disorders are studied using sleep study systems called Polysomnography that records several biophysical parameters during sleep. However, these are bulky and are typically located in a medical facility where patient monitoring is costly and quite inefficient. Home-based portable systems solve these problems to an extent but they record only a minimal number of channels due to limited battery life. To surmount this, wearable sleep system are desired which need to be unobtrusive and have long battery life. In this thesis, a novel sleep system architecture is presented that enables the design of an ultra low power sleep diagnostic system. This architecture is capable of extending the recording time to 120 hours in a wearable system which is an order of magnitude improvement over commercial wearable systems that record for about 12 hours. This architecture has in effect reduced the average power consumption of 5-6 mW per channel to less than 500 uW per channel. This has been achieved by eliminating sampled data architecture, reducing the wireless transmission rate and by moving the sleep scoring to the sensors. Further, ultra low power instrumentation amplifiers have been designed to operate in weak inversion region to support this architecture. A 40 dB chopper-stabilised low power instrumentation amplifiers to process EEG were designed and tested to operate from 1.0 V consuming just 3.1 uW for peak mode operation with DC servo loop. A 50 dB non-EEG amplifier continuous-time bandpass amplifier with a consumption of 400 nW was also fabricated and tested. Both the amplifiers achieved a high CMRR and impedance that are critical for wearable systems. Combining these amplifiers with the novel architecture enables the design of an ultra low power sleep recording system. This reduces the size of the battery required and hence enables a truly wearable system.Open Acces

State of the art of audio- and video based solutions for AAL

Working Group 3. Audio- and Video-based AAL ApplicationsIt is a matter of fact that Europe is facing more and more crucial challenges regarding health and social care due to the demographic change and the current economic context. The recent COVID-19 pandemic has stressed this situation even further, thus highlighting the need for taking action. Active and Assisted Living (AAL) technologies come as a viable approach to help facing these challenges, thanks to the high potential they have in enabling remote care and support. Broadly speaking, AAL can be referred to as the use of innovative and advanced Information and Communication Technologies to create supportive, inclusive and empowering applications and environments that enable older, impaired or frail people to live independently and stay active longer in society. AAL capitalizes on the growing pervasiveness and effectiveness of sensing and computing facilities to supply the persons in need with smart assistance, by responding to their necessities of autonomy, independence, comfort, security and safety. The application scenarios addressed by AAL are complex, due to the inherent heterogeneity of the end-user population, their living arrangements, and their physical conditions or impairment. Despite aiming at diverse goals, AAL systems should share some common characteristics. They are designed to provide support in daily life in an invisible, unobtrusive and user-friendly manner. Moreover, they are conceived to be intelligent, to be able to learn and adapt to the requirements and requests of the assisted people, and to synchronise with their specific needs. Nevertheless, to ensure the uptake of AAL in society, potential users must be willing to use AAL applications and to integrate them in their daily environments and lives. In this respect, video- and audio-based AAL applications have several advantages, in terms of unobtrusiveness and information richness. Indeed, cameras and microphones are far less obtrusive with respect to the hindrance other wearable sensors may cause to one’s activities. In addition, a single camera placed in a room can record most of the activities performed in the room, thus replacing many other non-visual sensors. Currently, video-based applications are effective in recognising and monitoring the activities, the movements, and the overall conditions of the assisted individuals as well as to assess their vital parameters (e.g., heart rate, respiratory rate). Similarly, audio sensors have the potential to become one of the most important modalities for interaction with AAL systems, as they can have a large range of sensing, do not require physical presence at a particular location and are physically intangible. Moreover, relevant information about individuals’ activities and health status can derive from processing audio signals (e.g., speech recordings). Nevertheless, as the other side of the coin, cameras and microphones are often perceived as the most intrusive technologies from the viewpoint of the privacy of the monitored individuals. This is due to the richness of the information these technologies convey and the intimate setting where they may be deployed. Solutions able to ensure privacy preservation by context and by design, as well as to ensure high legal and ethical standards are in high demand. After the review of the current state of play and the discussion in GoodBrother, we may claim that the first solutions in this direction are starting to appear in the literature. A multidisciplinary 4 debate among experts and stakeholders is paving the way towards AAL ensuring ergonomics, usability, acceptance and privacy preservation. The DIANA, PAAL, and VisuAAL projects are examples of this fresh approach. This report provides the reader with a review of the most recent advances in audio- and video-based monitoring technologies for AAL. It has been drafted as a collective effort of WG3 to supply an introduction to AAL, its evolution over time and its main functional and technological underpinnings. In this respect, the report contributes to the field with the outline of a new generation of ethical-aware AAL technologies and a proposal for a novel comprehensive taxonomy of AAL systems and applications. Moreover, the report allows non-technical readers to gather an overview of the main components of an AAL system and how these function and interact with the end-users. The report illustrates the state of the art of the most successful AAL applications and functions based on audio and video data, namely (i) lifelogging and self-monitoring, (ii) remote monitoring of vital signs, (iii) emotional state recognition, (iv) food intake monitoring, activity and behaviour recognition, (v) activity and personal assistance, (vi) gesture recognition, (vii) fall detection and prevention, (viii) mobility assessment and frailty recognition, and (ix) cognitive and motor rehabilitation. For these application scenarios, the report illustrates the state of play in terms of scientific advances, available products and research project. The open challenges are also highlighted. The report ends with an overview of the challenges, the hindrances and the opportunities posed by the uptake in real world settings of AAL technologies. In this respect, the report illustrates the current procedural and technological approaches to cope with acceptability, usability and trust in the AAL technology, by surveying strategies and approaches to co-design, to privacy preservation in video and audio data, to transparency and explainability in data processing, and to data transmission and communication. User acceptance and ethical considerations are also debated. Finally, the potentials coming from the silver economy are overviewed.publishedVersio

Perspectives of Renewable Energy in the Danube Region

The energy production in the Danube region is predominantly based on fossil and nuclear energy sources contributing to climate change and endangering the ecosystem and lowering the quality of life. While in the last decade the share of renewable energy sources (RES) has grown steadily in final energy consumption, the national energy strategies in the Danube region are still mainly based on fossil and nuclear sources. The international financial crisis and the prolonged recession have pushed the issues of environmental protection and sustainable energy production in the region into the background. The existing RES technologies and plants are in some cases only pilot or small scale projects and they can not spread to their full extent due to political, legal, administrative, economic and technical barriers. Although a lot of studies try to quantify the Renewable Energy Source (RES) potential in the EU and worldwide, the methodology of assessment varies from country to country, from author to author and from time to time. This makes impossible to compare the results because of the diverting assumptions, time horizons and methodology (NREL 2012). Moreover, any informed decision on energy policy should consider the interlinks of energy supply and consumption to ecological, economic and social dimensions. Thus, the goal of the book is to advance in the sound assessment of RES potentials in the Danube Region as weil as in understanding the ecological, economic and societal aspects related with the deployment of those potentials

Novel Methods for Loss of Mains Protection

Small-scale generation connected to distribution networks has increased significantly in recent years. This trend is driven by developments in distributed generation (DG) technologies, environmental concerns and economic reasons. The diffusion of generation into the distribution network level has many potential benefits, but it also raises challenges, such as unintentional islanding, which is hazardous to the safety of both personnel and equipment. Due to the safety risks, all DG units need to be equipped with a loss of mains (LOM) protection scheme capable of rapidly detecting and stopping islanding. LOM protection methods can be divided into passive, active and communication-based methods. Passive methods rely on detecting islanding by monitoring chosen system quantities. These methods are affordable and applicable to all types of DG units, but their performance is highly dependent on the local power imbalances between the production and consumption in the islanded zone. Most, if not all, passive methods, fail to detect islanding if the local production closely matches the local consumption. The set of power imbalance combinations that lead to non-detected islanding is referred to as the non-detection zone (NDZ). Active methods are based on deliberately injecting small perturbations to the grid and monitoring the response of the system. These methods generally have smaller NDZ than passive methods. However, this comes at the cost of degraded power quality. Communication-based methods rely on other means than the local monitoring of system quantities, which makes them immune to the NDZ problem. However, these methods tend to be costly.The performance of passive and active methods can be improved by applying more sensitive LOM protection settings. However, if the LOM protection settings are too sensitive, voltage dips caused by faults in the transmission grid may result in a cascading disconnection of DG. In order to avoid such risks, which threaten the system’s stability, many grid codes include fault-ridethrough (FRT) requirements, which specify the depth and duration of voltage dips which DG units need to be able to withstand. FRT requirements often also require the DG units to feed reactive current to the grid during the voltage dip in order to support the system voltages. The work conducted for this thesis indicates that FRT requirements significantly degrade the performance of LOM protection. This thesis also studies how the type of the protected DG unit affects LOM protection. The frequency of an islanded circuit sustained by a directly-coupled synchronous generator is determined by the local active power imbalance, whereas the frequency of an islanded circuit sustained by a converter-coupled DG unit is determined by the local reactive power imbalance. However, when there are both directly-coupled synchronous generators and convertercoupled DG units in an islanded circuit, the synchronous generator seems to dominate these relationships. This has significant implications on the performance of active LOM protection schemes.One of the main issues distribution system operators face when they are evaluating the adequacy of LOM protection for DG installations is the lack of suitable analysis tools. This thesis proposes a novel LOM risk management procedure which utilizes the existing analysis tools embedded in a modern network information system (NIS). This NIS-based procedure analyzes what kind of power imbalance combinations are possible in the studied network sections. Based on the possible combinations of power imbalances and predefined NDZ mappings of optional LOM protection schemes, the procedure tells protection engineers if there are any risks of non-detected islanding in the analyzed network sections and proposes which LOM protection schemes would be most suitable for each DG installation. Although the proposed LOM risk management tool is presented at the concept level only here, it is clearly a promising area for future research.Two active LOM protection methods and one communication-based protection automation concept were also developed during this thesis work. The first of the active LOM protection methods is based on forcing the frequency of an islanded circuit out of the utilized frequency thresholds by constant injection of reactive power pulses and a dedicated reactive power versus frequency droop. The knowledge gained during the development of this method resulted in a second, significantly more advanced, active LOM protection scheme. This is based on forcing the rate-ofchange-of-frequency of an islanded circuit to a desired value by applying a dedicated reactive power versus frequency droop. This method is able to detect islanding rapidly and reliably even if the local power imbalances are negligible. Moreover, this can be achieved with a very modest injection of reactive power. The communication-based protection automation concept is designed to solve typical DG related protection challenges and to automatically change the feeding path of the protected DG unit in case if the original feeding route becomes faulted. However, the successfulness of the automatic feeding path changing depends on many factors such as DG unit type, network parameters and the momentary input power provided by the primary energy source.The methods developed in this thesis have slightly different purposes. The proposed NIS-based LOM risk assessment procedure is useful for evaluating the adequacy of existing LOM protection as well as for choosing optimal LOM protection schemes for new DG installations. If the LOM risk assessment procedure indicates that the local power imbalances will always be very large, then passive LOM protection schemes are a sensible choice. However, should the LOM risk assessment procedure reveal that the local power imbalances could be so small that reliable LOM protection cannot be ensured with passive LOM protection schemes, then active or communication-based LOM protection schemes are preferable. Active LOM protection schemes are suitable if the ratio of converter-coupled to directly-coupled generator capacity in the analyzed zone is large. This is because certain active LOM schemes, such as the one proposed in this thesis, are able to detect islanding reliably and rapidly even if the local active- and reactive power imbalances would be negligible, provided that the ratio between converter coupled to directly coupled synchronous generator capacity is large. However, if a significant proportion of the generation capacity in the analyzed network section is synchronous generator based, then sensitive and rapid LOM protection cannot always be guaranteed. In such cases, it is advisable to utilize advanced communication-based LOM protection schemes which are immune to the NDZ problem

NASA Tech Briefs, February 1994

Topics covered include: Test and Measurement; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Report

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences