Retrofiting Existing Optical Fiber Infrastructure to Mitigate Geohazard Risk: The TGP Case

Abstract Optical fiber cables (OFC) are well known for their use in communications. They offer long distance and fast transmission rate capabilities. OFC are the perfect companion of hydrocarbon and water transport system as part of the physical layer of the communication services and SCADA of the operating companies. As an example, the TGP system has more than 1400 km of cables laid in its Right-of-Way (ROW) which are in use since the beginning of its operation in 2004. More recently OFC started to be used as sensors. In such applications, a communication cable (CC) can be turned into a continuous temperature sensor allowing for leak and erosion detection. A strain monitoring cable (SMC) can also be spliced to the CC for landslide and subsidence detection in selected areas. In the case of very large soil displacement, it is common to observe the strain induced on the CC. From what precedes, existing OFC infrastructures can be taken advantage of to retrofit pipelines with monitoring instrumentation. The current work describes how an existing CC is retrofitted to provide information about the TGP transport system’s integrity. When accurate monitoring of a landslide is required, a dedicated sensing cable is installed locally and connected to the CC. Elsewhere the CC is being measured to detect and locate events as erosion or landslide in position where the geohazard risk present lower probability. Such approach not only improves geohazard risk management, but it also indicates early sign of stress on the cable that can lead to its rupture, mitigating service interruption probability.

Download Full-text

Mitigation of geohazard risk along transportation infrastructures with optical fiber distributed sensing

Journal of Civil Structural Health Monitoring ◽

10.1007/s13349-021-00492-x ◽

2021 ◽

Author(s):

Fabien Ravet ◽

Fabien Briffod ◽

Alexandre Goy ◽

Etienne Rochat

Keyword(s):

Optical Fiber ◽

Distributed Sensing ◽

Transportation Infrastructures ◽

Geohazard Risk

Download Full-text

Avian Haemosporidian Diversity on Sardinia: A First General Assessment for the Insular Mediterranean

Diversity ◽

10.3390/d13020075 ◽

2021 ◽

Vol 13 (2) ◽

pp. 75

Author(s):

Irene Pellegrino ◽

Luca Ilahiane ◽

Giovanni Boano ◽

Marco Cucco ◽

Marco Pavia ◽

...

Keyword(s):

Linear Models ◽

Parasite Community ◽

Breeding Birds ◽

Lower Probability ◽

Long Distance ◽

Breeding Bird ◽

Bird Populations ◽

Total Prevalence ◽

Western Palearctic ◽

Host Parasite

The Western Palearctic is one of the most investigated regions for avian haemosporidian parasites (Haemoproteus, Plasmodium and Leucocytozoon), yet geographic gaps in our regional knowledge remain. Here, we report the first haemosporidian screening of the breeding birds from Sardinia (the second-largest Mediterranean Island and a biodiversity hotspot), and the first for the insular Mediterranean in general. We examined the occurrence of haemosporidians by amplifying their mtDNA cytb gene in 217 breeding birds, belonging to 32 species. The total prevalence of infected birds was 55.3%, and of the 116 haplotypes recovered, 84 were novel. Despite the high number of novel lineages, phylogenetic analysis did not highlight Sardinia-specific clades; instead, some Sardinian lineages were more closely related to lineages previously recovered from continental Europe. Host-parasite network analysis indicated a specialized host-parasite community. Binomial generalized linear models (GLMs), performed at the community level, suggested an elevational effect on haemosporidian occurrence probability (negative for Haemoproteus; positive for Leucocytozoon) likely due to differences in the abundance of insect vectors at different elevations. Furthermore, a GLM revealed that sedentary birds showed a higher probability of being infected by novel haplotypes and long-distance migrants showed a lower probability of novel haplotype infection. We hypothesize that the high diversity of haemosporidians is linked to the isolation of breeding bird populations on Sardinia. This study adds to the growing knowledge on haemosporidians lineage diversity and distribution in insular environments and presents new insights on potential host-parasite associations.

Download Full-text

Novel Measurement System With Optical Fiber Sensor for Strain Distributions in Welded Tubular Joints

Volume 5: Materials Technology; CFD and VIV ◽

10.1115/omae2008-57713 ◽

2008 ◽

Cited By ~ 2

Author(s):

Hideaki Murayama ◽

Kazuro Kageyama ◽

Kohei Ohara ◽

Kiyoshi Uzawa ◽

Makoto Kanai ◽

...

Keyword(s):

Optical Fiber ◽

Spatial Resolution ◽

Measurement System ◽

Strain Distribution ◽

Welded Joint ◽

Optical Fiber Sensor ◽

Weld Line ◽

Fiber Sensor ◽

Strain Monitoring ◽

Tubular Joint

Defects and damage in a structural joint can trigger a critical degradation or collapse of the structure. Among joints, welded joints have many uncertainties, such as remaining stress, initial defects, and heat-affected zone. Such uncertainties in a welded joint can also induce a strain fluctuation, when they are subjected to a load. Conversely, the strain fluctuation along the weld line may represent the presence of uncertainties in the welded joint. This means that monitoring strain distribution along the weld line can be good way to assess their integrity and improve reliability of the structure. We have developed a novel distributed strain measurement technique which can measure strain distributions along fiber Bragg gratings (FBG) in an optical fiber and has the high spatial resolution and we applied it to strain monitoring of a welded tubular joint. The spatial resolution o is less than 1 mm and it was confirmed by measurement simulations and experiments. Then, we measured the strain distributions along the weld line of the tubular joint of a steel pipe subjected to a tensile load by the developed measurement system. We could successfully measure the development of the strain distribution along the weld line, where the sharply fluctuating strain distributions resulting from some defects were observed. In this paper, we describe the measurement principle and performance of the optical fiber sensor, and then show the results of strain monitoring in the welded joint.

Download Full-text

Study of Optical Fiber Design Parameters in Fiber Optics Communications

Kurdistan Journal of Applied Research ◽

10.24017/science.2017.3.52 ◽

2017 ◽

Vol 2 (3) ◽

pp. 302-308 ◽

Cited By ~ 1

Author(s):

Salim Qadir Mohammed ◽

Asaad M. Asaad M. Al-Hindawi

Keyword(s):

Optical Fiber ◽

Fiber Optics ◽

Numerical Aperture ◽

Design Parameters ◽

Light Sources ◽

Long Distance ◽

Graded Index ◽

Large Bandwidth ◽

Telecommunication Infrastructure ◽

Distance Communication

Fiber optics is an important part in the telecommunication infrastructure. Large bandwidth and low attenuation are features for the fiber optics to provide gigabit transmission. Nowadays, fiber optics are used widely in long distance communication and networking to provide the required information traffic for multimedia applications. In this paper, the optical fiber structure and the operation mechanism for multimode and single modes are analyzed. The design parameters such as core radius, numerical aperture, attenuation, dispersion and information capacity for step index and graded index fibers are studied, calculated and compared for different light sources.

Download Full-text

An Improved High-Intelligence Method of Gas and Oil Pipeline Prewarning System in Real Soil Environment

Mathematical Problems in Engineering ◽

10.1155/2021/6673325 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Fang Wang ◽

Jichuan Xing ◽

Jinxin Li ◽

Feng Zhao ◽

Shufeng Zhang

Keyword(s):

Optical Fiber ◽

Real Time ◽

Recognition Accuracy ◽

Signal Acquisition ◽

Soil Environment ◽

Long Distance ◽

Vibration Signals ◽

Oil Pipeline ◽

Time Performance ◽

High Intelligence

With the development of technology, the total extent of global pipeline transportation is also increased. However, the traditional long-distance optical fiber prewarning system has poor real-time performance and high false alarm rate when recognizing events threatening pipeline safety. The same vibration signal would vary greatly when collected in different soil environments and this problem would reduce the signal recognition accuracy of the prewarning system. In this paper, we studied this effect theoretically and analyzed soil vibration signals under different soil conditions. Then we studied the signal acquisition problem of long-distance gas and oil pipeline prewarning system in real soil environment. Ultimately, an improved high-intelligence method was proposed for optimization. This method is based on the real application environment, which is more suitable for the recognition of optical fiber vibration signals. Through experiments, the method yielded high recognition accuracy of above 95%. The results indicate that the method can significantly improve signal acquisition and recognition and has good adaptability and real-time performance in the real soil environment.

Download Full-text

Long-Distance Time Transfer in Optical Fiber Networks Using a Cascaded Taming Technology

Mathematical Problems in Engineering ◽

10.1155/2021/8860028 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Ding Chen ◽

Jiangning Xu ◽

Yifeng Liang ◽

Shan Jiang ◽

Hongyang He

Keyword(s):

Optical Fiber ◽

High Precision ◽

Wavelength Division Multiplexing ◽

Time Synchronization ◽

Atomic Clock ◽

Process Time ◽

Long Distance ◽

Time Service ◽

Time Frequency ◽

Fiber Link

In order to meet the time service needs of high-precision, long-distance, and multinode optical network, this paper proposes a new time synchronization solution, which combines the wavelength division multiplexing (WDM) technology with cascaded taming clock technology. The WDM technology is used for time synchronization between each pair of master-slave nodes. In the system, there are two wavelengths on the fiber link between the master node and the slave node for transmitting signals. 1 plus per second (PPS) signal, time code signal, and 10 MHz signal are, respectively, and successively, sent to the optical fiber link. By solving the one-way delay through analysis of error contribution and link characteristics of the time transmission process, time synchronization of the master-slave nodes pair is achieved. Furthermore, the authors adopt cascaded taming clock technology to ensure accurate time synchronization of each node. A 700 km long-distance time-frequency synchronization system is constructed in the laboratory. The system uses a cesium atomic clock as the reference clock source and transmits the signals through 8 small rubidium atomic clocks (RB clocks) hierarchically. Results from the experiment show that the long-term time stability is 47.5 ps/104 s. The system’s structural characteristics and the experiment results meet the requirements to allow practical use of high-precision time synchronization in networks. This proposed solution can be applied in various civil, commercial, and military fields.

Download Full-text

The Role of Migration in Maintaining the Transmission of Avian Influenza in Waterfowl: A Multisite Multispecies Transmission Model along East Asian-Australian Flyway

Canadian Journal of Infectious Diseases and Medical Microbiology ◽

10.1155/2018/3420535 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Akira Endo ◽

Hiroshi Nishiura

Keyword(s):

Avian Influenza ◽

Reproduction Number ◽

Transmission Rate ◽

Temporal Variations ◽

Transmission Model ◽

Global Dynamics ◽

Long Distance ◽

Transmission Potential ◽

Influenza Transmission

Background. Migratory waterfowl annually migrate over the continents along the routes known as flyways, serving as carriers of avian influenza virus across distant locations. Prevalence of influenza varies with species, and there are also geographical and temporal variations. However, the role of long-distance migration in multispecies transmission dynamics has yet to be understood. We constructed a mathematical model to capture the global dynamics of avian influenza, identifying species and locations that contribute to sustaining transmission.Methods. We devised a multisite, multispecies SIS (susceptible-infectious-susceptible) model, and estimated transmission rates within and between species in each geographical location from prevalence data. Parameters were directly sampled from posterior distribution under Bayesian inference framework. We then analyzed contribution of each species in each location to the global patterns of influenza transmission.Results. Transmission and migration parameters were estimated by Bayesian posterior sampling. The basic reproduction number was estimated at 1.1, slightly above the endemic threshold. Mallard was found to be the most important host with the highest transmission potential, and high- and middle-latitude regions appeared to act as hotspots of influenza transmission. The local reproduction number suggested that the prevalence of avian influenza in the Oceania region is dependent on the inflow of infected birds from other regions.Conclusion. Mallard exhibited the highest transmission rate among the species explored. Migration was suggested to be a key factor of the global prevalence of avian influenza, as transmission is locally sustainable only in the northern hemisphere, and the virus could be extinct in the Oceania region without migration.

Download Full-text

The Optical Fiber Strain Monitoring Technology of Large-Scale Bridge

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.3417 ◽

2012 ◽

Vol 446-449 ◽

pp. 3417-3421

Author(s):

Shu Li Chen ◽

Mu Biao Su

Keyword(s):

Optical Fiber ◽

Large Scale ◽

Research Result ◽

Strain Sensor ◽

Bridge Structure ◽

Stress Monitoring ◽

State Monitoring ◽

Strain Monitoring ◽

Reliable Performance ◽

Structure State

Application situation of optical fiber strain sensor used in bridge structure state monitoring is detailed introduced in this paper, two bridges which optical fiber strain sensor is adopted in construction stage stress monitoring and long-time stress monitoring in our country are introduced as example. According to the theoretical analysis of structures, the strain monitoring locations are selected. The composite technology between optical fiber strain sensor and concrete is researched. The installation technology and protect method between optical fiber strain sensor and steel girder are extracted, and advanced acquisition software is explored. Finally, the application foreground of optical fiber strain sensor is discussed. The research result indicates that the optical fiber strain sensor is extraordinary suitable for state monitoring of bridge structure because it has the merits of light structure and reliable performance.

Download Full-text