Fault Isolation in Environmental Controls Systems of Commercial Transports

Recovery boilers play a key role in chemical pulp mills. Early detection of defects, such as water leaks, in a recovery boiler is critical to the prevention of explosions, which can occur when water reaches the molten smelt bed of the boiler. Early detection is difficult to achieve because of the complexity and the multitude of recovery boiler operating parameters. Multiple faults can occur in multiple components of the boiler simultaneously, and an efficient and robust fault isolation method is needed. In this paper, we present a new fault detection and isolation scheme for multiple faults. The proposed approach is based on principal component analysis (PCA), a popular fault detection technique. For fault detection, the Mahalanobis distance with an exponentially weighted moving average filter to reduce the false alarm rate is used. This filter is used to adapt the sensitivity of the fault detection scheme versus false alarm rate. For fault isolation, the reconstruction-based contribution is used. To avoid a combinatorial excess of faulty scenarios related to multiple faults, an iterative approach is used. This new method was validated using real data from a pulp and paper mill in Canada. The results demonstrate that the proposed method can effectively detect sensor faults and water leakage.

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Disentangling the role of shared ancestry and the environment on leaf stable isotopes

10.32942/osf.io/mfhve ◽

2019 ◽

Author(s):

Marko J. Spasojevic ◽

Sören Weber1

Keyword(s):

Stable Isotopes ◽

Environmental Conditions ◽

Evolutionary History ◽

Environmental Control ◽

Phylogenetic Signal ◽

Individual Species ◽

Habitat Types ◽

Δ13c And Δ15n ◽

Environmental Controls ◽

Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

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Environmental controls on estuarine nitrifying communities along a salinity gradient

Aquatic Microbial Ecology ◽

10.3354/ame01847 ◽

2017 ◽

Vol 80 (2) ◽

pp. 167-180 ◽

Cited By ~ 3

Author(s):

M Monteiro ◽

J Séneca ◽

L Torgo ◽

DFR Cleary ◽

NCM Gomes ◽

...

Keyword(s):

Salinity Gradient ◽

Environmental Controls

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Combination of multiple reasoning modes in an intelligent fault isolation system

10.2514/6.1991-3949 ◽

1991 ◽

Author(s):

GEORGE VAMOS ◽

CHARLENE KOWALSKI

Keyword(s):

Fault Isolation ◽

Isolation System

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Advanced T-LSIM System Detections using Amplified External Isolated Source-Sense Unit

10.31399/asm.cp.istfa2018p0200 ◽

2018 ◽

Author(s):

Zhi Jie Lau ◽

Chris Philips

Keyword(s):

Fault Isolation ◽

Isolation Technique ◽

Laser Signal ◽

Signal Injection ◽

Sense Unit ◽

Types Of Faults

Abstract Thermal-Laser Signal Injection Microscopy (T-LSIM) is a widely used fault isolation technique. Although there are several T-LSIM systems on the market, each is limited in terms of the voltage and current it can produce. In this paper, the authors explain how they incorporated an Amplified External Isolated Source-Sense (AxISS) unit into their T-LSIM platform, increasing its current sourcing capability and voltage biasing range. They also provide examples highlighting the types of faults and failures that the modified system can detect.

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Advanced Non-Destructive Fault Isolation Techniques for PCB Substrates Using Magnetic Current Imaging and Terahertz Time Domain Reflectometry

10.31399/asm.cp.istfa2018p0043 ◽

2018 ◽

Author(s):

Daechul Choi ◽

Yoonseong Kim ◽

Jongyun Kim ◽

Han Kim

Keyword(s):

Time Domain ◽

Quantum Interference ◽

Flip Chip ◽

Imaging System ◽

Time Domain Reflectometry ◽

Fault Isolation ◽

Magnetic Current ◽

Isolation Techniques ◽

Super Conducting ◽

Non Destructive

Abstract In this paper, we demonstrate cases for actual short and open failures in FCB (Flip Chip Bonding) substrates by using novel non-destructive techniques, known as SSM (Scanning Super-conducting Quantum Interference Device Microscopy) and Terahertz TDR (Time Domain Reflectometry) which is able to pinpoint failure locations. In addition, the defect location and accuracy is verified by a NIR (Near Infra-red) imaging system which is also one of the commonly used non-destructive failure analysis tools, and good agreement was made.

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