AN INHERENTLY SAFER LAYOUT DESIGN FOR THE LIQUEFACTION PROCESS OF AN FLNG PLANT

Floating Liquefied Natural Gas (FLNG) facilities have limited space available and a high possibility of accidents occurring. The severity of consequences requires an inherently safer layout design. Scope of the liquefaction process requires to determine the size of utilities, operating costs, the deck area and the number of LNG trains. The layout of the liquefaction process plays a key role in defining operational and economical safety of the whole FLNG plant. The present study focuses on developing a novel methodology to design an inherently and optimally safer layout for the generic multi-deck liquefaction process of an FLNG plant. The integrated inherent safety principle is applied at the early phases of the layout design considering inherent safety and cost indices in three different layout options, and for the final design the most optimal option was selected. The proven indexing approach quantified the associated risks in all units. Safety measures were undertaken to eliminate or reduce the risk to an acceptable level. The results showed that the economic losses due to domino effects were limited by an improved layout design and passive control strategies. This study only dealt with evaluation and analysis of critical units of the plant due to a lack of detailed information at the early phase of the design. However, the proposed method plays a positive role in obtaining an inherently safer layout design of any multi-deck plants.

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Prevalence of mastitis in Nigerian livestock: a Review

Open Veterinary Science ◽

10.1515/ovs-2020-0101 ◽

2020 ◽

Vol 1 (1) ◽

pp. 20-29

Author(s):

Hussaini Ojagefu Adamu ◽

Rahimat Oshuwa Hussaini ◽

Cedric Obasuyi ◽

Linus Irefo Anagha ◽

Gabriel Oscy Okoduwa

Keyword(s):

Control Strategies ◽

Dairy Farms ◽

Livestock Production ◽

Sub Saharan Africa ◽

Economic Losses ◽

Ecological Development ◽

Management Plans ◽

Sub Saharan ◽

Control And Management ◽

The Impact

AbstractMastitis is a disease of livestock that directly impede livestock production and thus hindering the socio-ecological development of sub-Saharan Africa. Studies have estimated the prevalence of this disease in 30% of Africa countries, with Ethiopia having the highest prevalence. The coverage is low, despite the wide livestock and dairy farms distribution in Africa. Furthermore, estimated economic losses due to the impact of mastitis are lacking in Nigeria. The disease is endemic in Nigeria as indicated by the available data and there are no proposed management plans or control strategies. This review is thus presented to serve as a wakeup call to all parties involved to intensify efforts towards the diagnosis, control, and management of the disease in Nigeria.

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Molecular detection and genetic diversity of Leucocytozoon sabrazesi in chickens in Thailand

Scientific Reports ◽

10.1038/s41598-021-96241-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Runglawan Chawengkirttikul ◽

Witchuta Junsiri ◽

Amaya Watthanadirek ◽

Napassorn Poolsawat ◽

Sutthida Minsakorn ◽

...

Keyword(s):

Genetic Diversity ◽

Egg Production ◽

Control Strategies ◽

Amino Acid Sequences ◽

Economic Losses ◽

Nested Polymerase Chain Reaction ◽

Blood Samples ◽

Tropical Regions ◽

Vaccination Programs ◽

High Entropy

AbstractLeucocytozoon sabrazesi is the intracellular protozoa of leucocytozoonosis, which is transmitted by the insect vectors and affects chickens in most subtropical and tropical regions of the globe, except South America, and causing enormous economic losses due to decreasing meat yield and egg production. In this study, L. sabrazesi gametocytes have been observed in the blood smears, and molecular methods have been used to analyse the occurrence and genetic diversity of L. sabrazesi in blood samples from 313 chickens raised in northern, western and southern parts of Thailand. The nested polymerase chain reaction (nested PCR) assay based on the cytb gene revealed that 80.51% (252/313) chickens were positive of L. sabrazesi. The phylogenetic analysis indicated that L. sabrazesi cytb gene is conserved in Thailand, showed 2 clades and 2 subclades with similarity ranged from 89.5 to 100%. The diversity analysis showed 13 and 18 haplotypes of the sequences from Thailand and from other countries, respectively. The entropy analyses of nucleic acid sequences showed 26 high entropy peaks with values ranging from 0.24493 to 1.21056, while those of amino acid sequences exhibited 5 high entropy peaks with values ranging from 0.39267 to 0.97012. The results; therefore, indicate a high molecular occurrence of L. sabrazesi in chicken blood samples with the associated factors that is statistically significant (p < 0.05). Hence, our results could be used to improve the immunodiagnostic methods and to find appropriate preventive control strategies or vaccination programs against leucocytozoonosis in order to mitigate or eliminate the harmful impact of this infection on chicken industry.

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Development of the first georeferenced map of Rhipicephalus (Boophilus) spp. in Mexico from 1970 to date and prediction of its spatial distribution

Geospatial health ◽

10.4081/gh.2018.624 ◽

2018 ◽

Vol 13 (1) ◽

Cited By ~ 2

Author(s):

Yazmin Alcala-Canto ◽

Juan Antonio Figueroa-Castillo ◽

Froylán Ibarra-Velarde ◽

Yolanda Vera-Montenegro ◽

María Eugenia Cervantes-Valencia ◽

...

Keyword(s):

Spatial Distribution ◽

Environmental Variables ◽

Control Strategies ◽

Integrated Control ◽

Area Under The Curve ◽

Entropy Method ◽

Distribution Model ◽

Economic Losses ◽

Precipitation Seasonality ◽

Epidemiological Risk

The tick genus Ripicephalus (Boophilus), particularly R. microplus, is one of the most important ectoparasites that affects livestock health and considered an epidemiological risk because it causes significant economic losses due, mainly, to restrictions in the export of infested animals to several countries. Its spatial distribution has been tied to environmental factors, mainly warm temperatures and high relative humidity. In this work, we integrated a dataset consisting of 5843 records of Rhipicephalus spp., in Mexico covering close to 50 years to know which environmental variables mostly influence this ticks’ distribution. Occurrences were georeferenced using the software DIVA-GIS and the potential current distribution was modelled using the maximum entropy method (Maxent). The algorithm generated a map of high predictive capability (Area under the curve = 0.942), providing the various contribution and permutation importance of the tested variables. Precipitation seasonality, particularly in March, and isothermality were found to be the most significant climate variables in determining the probability of spatial distribution of Rhipicephalus spp. in Mexico (15.7%, 36.0% and 11.1%, respectively). Our findings demonstrate that Rhipicephalus has colonized Mexico widely, including areas characterized by different types of climate. We conclude that the Maxent distribution model using Rhipicephalus records and a set of environmental variables can predict the extent of the tick range in this country, information that should support the development of integrated control strategies.

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To React or Not to React: The Dilemma of Fish Immune Systems Facing Myxozoan Infections

Frontiers in Immunology ◽

10.3389/fimmu.2021.734238 ◽

2021 ◽

Vol 12 ◽

Author(s):

Astrid S. Holzer ◽

M. Carla Piazzon ◽

Damien Barrett ◽

Jerri L. Bartholomew ◽

Ariadna Sitjà-Bobadilla

Keyword(s):

Immune Responses ◽

Immune Evasion ◽

B Lymphocyte ◽

Control Strategies ◽

Abiotic Factors ◽

Passive Immunization ◽

Life Cycles ◽

Economic Losses ◽

Special Focus ◽

Host Immune System

Myxozoans are microscopic, metazoan, obligate parasites, belonging to the phylum Cnidaria. In contrast to the free-living lifestyle of most members of this taxon, myxozoans have complex life cycles alternating between vertebrate and invertebrate hosts. Vertebrate hosts are primarily fish, although they are also reported from amphibians, reptiles, trematodes, mollusks, birds and mammals. Invertebrate hosts include annelids and bryozoans. Most myxozoans are not overtly pathogenic to fish hosts, but some are responsible for severe economic losses in fisheries and aquaculture. In both scenarios, the interaction between the parasite and the host immune system is key to explain such different outcomes of this relationship. Innate immune responses contribute to the resistance of certain fish strains and species, and the absence or low levels of some innate and regulatory factors explain the high pathogenicity of some infections. In many cases, immune evasion explains the absence of a host response and allows the parasite to proliferate covertly during the first stages of the infection. In some infections, the lack of an appropriate regulatory response results in an excessive inflammatory response, causing immunopathological consequences that are worse than inflicted by the parasite itself. This review will update the available information about the immune responses against Myxozoa, with special focus on T and B lymphocyte and immunoglobulin responses, how these immune effectors are modulated by different biotic and abiotic factors, and on the mechanisms of immune evasion targeting specific immune effectors. The current and future design of control strategies for myxozoan diseases is based on understanding this myxozoan-fish interaction, and immune-based strategies such as improvement of innate and specific factors through diets and additives, host genetic selection, passive immunization and vaccination, are starting to be considered.

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Structural sensitivity of spiral vortex breakdown

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.34 ◽

2013 ◽

Vol 720 ◽

pp. 558-581 ◽

Cited By ~ 48

Author(s):

Ubaid Ali Qadri ◽

Dhiren Mistry ◽

Matthew P. Juniper

Keyword(s):

Stability Analysis ◽

Passive Control ◽

Stokes Equations ◽

Vortex Breakdown ◽

Control Strategies ◽

Axial Component ◽

Azimuthal Mode ◽

Global Mode ◽

Structural Sensitivity ◽

Spiral Vortex

AbstractPrevious numerical simulations have shown that vortex breakdown starts with the formation of a steady axisymmetric bubble and that an unsteady spiralling mode then develops on top of this. We investigate this spiral mode with a linear global stability analysis around the steady bubble and its wake. We obtain the linear direct and adjoint global modes of the linearized Navier–Stokes equations and overlap these to obtain the structural sensitivity of the spiral mode, which identifies the wavemaker region. We also identify regions of absolute instability with a local stability analysis. At moderate swirls, we find that the $m= - 1$ azimuthal mode is the most unstable and that the wavemaker regions of the $m= - 1$ mode lie around the bubble, which is absolutely unstable. The mode is most sensitive to feedback involving the radial and azimuthal components of momentum in the region just upstream of the bubble. To a lesser extent, the mode is also sensitive to feedback involving the axial component of momentum in regions of high shear around the bubble. At an intermediate swirl, in which the bubble and wake have similar absolute growth rates, other researchers have found that the wavemaker of the nonlinear global mode lies in the wake. We agree with their analysis but find that the regions around the bubble are more influential than the wake in determining the growth rate and frequency of the linear global mode. The results from this paper provide the first steps towards passive control strategies for spiral vortex breakdown.

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Floating and float-in LNG solutions for Australian and international locations

The APPEA Journal ◽

10.1071/aj13086 ◽

2014 ◽

Vol 54 (2) ◽

pp. 513

Author(s):

Brian Haggerty ◽

Mark Hoffmann

Keyword(s):

Quantitative Risk Assessment ◽

Process Efficiency ◽

Inherent Safety ◽

Gas Field ◽

Field Development ◽

Management Processes ◽

Operations And Maintenance ◽

Potential Applications ◽

Near Shore ◽

Liquefaction Process

The costs of LNG projects have increased worldwide. FLNG and float-in near-shore facilities reduce the total amount of infrastructure required for an offshore gas field development. Woodside has developed a range of FLNG and float-in/near-shore facility concepts. In the process key lessons from more than a dozen potential applications were obtained. The optimisation of process efficiency and availability versus operability and maintainability ends up in a different balance to onshore LNG or FPSO. Knowledge of LNG and FPSO operations and maintenance is required to design FLNG. Quantitative risk assessment (QRA) does not fully define the safety of the facilities. The application of proven philosophies, simplicity, and management of concurrent operations drives inherent safety. The choice of refrigerants for the liquefaction process on an offshore facility is not straightforward (e.g. nitrogen does not necessarily offer as big a safety advantage as often assumed). The design-one-build-many strategy can offer significant advantages if a number of similar facilities can be sanctioned in quick succession; however, this is not generally available and a bespoke solution will generally be optimum. Concrete near-shore facilities have superior durability and potentially lower maintenance but require significant pre-FID decisions and investment for graving docks, etc. FLNG offers greater certainty of execution outcome because of the fabrication and construction in the controlled shipyard environment; however, experience and management processes are required to manage the novelty aspects. Earlier contracting and execution decisions are required for floating LNG than for onshore LNG or standard FPSOs.

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Validation and Implementation of Control Strategies for Liquid Composite Molding Processes

Materials ◽

10.1115/imece2003-43521 ◽

2003 ◽

Author(s):

Mathieu Devillard ◽

Kuang-Ting Hsiao ◽

Suresh G. Advani

Keyword(s):

Active Control ◽

Passive Control ◽

Control Strategies ◽

Process Models ◽

Injection System ◽

Composite Part ◽

Rtm Process ◽

Flow Disturbances ◽

Filling Time ◽

Optimization Search

The manufacturing of polymeric composites ranges from using a rudimentary hand lay-up to the use of automated processes such as Liquid Composite Modeling (LCM) developed over the past decades in order to increase the yield of manufactured composite parts. In these processes, fiber preforms are placed in a closed mold and resin is infused into the mold to saturate the preform. After the resin cures, the mold is opened and the net shape composite part is demolded. However, by introducing more complexity into the part, one also introduces higher probability of flow disturbances, such as race tracking along preform edges, into the molding system. This can lead to incomplete saturation of fiber performs resulting in flaws such as dry spots in the composite part. The strength and existence of race-tracking is a function of the fabric type, perform manufacturing method, and its placement in the mold. It can vary from one part to the next in the same production run, and therefore it is not repeatable. In this work, after illustrating experimentally the unpredictability of variation of race-tracking and its influence on the flow, two approaches have been investigated and validated to address this issue associated with the variation of inherent disturbances in LCM processes. An active control strategy method using process models and simulations along with sensing and control to address flow disturbances during the impregnation stage of the process was shown to be reliable and effective for Resin Transfer Molding (RTM) process. In an attempt to improve the automation of RTM process, a modular RTM workstation including all hardware and software necessary to implement active control strategies for various part geometries and a novel injection system was designed and tested. In addition, a passive control method for Vaccum Assisted RTM (VARTM) aimed at optimizing the placement of distribution media for a given set-up in order to reduce dry spot formation and filling time was developed and validated experimentally. The optimization method employs numerical flow simulations and global optimization search techniques (Genetic algorithm) to generate the design for strategic flow control system.

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Passive Control Techniques for Seismic Protection of Chemical Plants

Volume 9: Seismic Engineering ◽

10.1115/pvp2020-21226 ◽

2020 ◽

Author(s):

Keisuke Minagawa ◽

Fabrizio Paolacci

Keyword(s):

Passive Control ◽

Base Isolation ◽

Seismic Damage ◽

Pressure Vessels ◽

Chemical Plant ◽

Seismic Protection ◽

Economic Losses ◽

Chemical Plants ◽

Northridge Earthquake ◽

Control Techniques

Abstract Seismic damage of chemical plant facilities (pressure vessels, piping, storage tanks, etc..) can causes human and economic losses as well as heavy environmental damages. Therefore, it is of paramount importance to reduce such a consequences. The passive control techniques (PCT) as dampers or base isolation can represent an effective technique to mitigate the major damage caused by earthquakes. Viscous dampers, tuned mass dampers and base isolators are well-known passive control devices successfully applied to civil structures, as demonstrated during the last big events as Northridge earthquake in 1994, the Kobe earthquake in 1995, the Great East Japan earthquake in 2011. The scarce application to major hazard industrial facilities as chemical plants poses some questions, including the selection of suitable devices, their real applicability and effectiveness, because of the strict requirements of chemical plant equipment in terms of safety and business continuity. Therefore, this study aim at analyzing the possible applications of the most renew passive control techniques for seismic protection for chemical plant components. In this respect, a complete review of typical seismic damage of industrial (chemical) facilities and the investigation of the applicability of PCT as mitigation strategy is offered for all possible structural typologies of units presents in a plant.

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Infectious Bronchitis Virus Evolution, Diagnosis and Control

Veterinary Sciences ◽

10.3390/vetsci7020079 ◽

2020 ◽

Vol 7 (2) ◽

pp. 79 ◽

Cited By ~ 2

Author(s):

Matteo Legnardi ◽

Claudia Maria Tucciarone ◽

Giovanni Franzo ◽

Mattia Cecchinato

Keyword(s):

Infectious Bronchitis Virus ◽

Immune Escape ◽

Control Strategies ◽

Rapid Evolution ◽

Emerging Diseases ◽

Economic Losses ◽

Recombination Rates ◽

Infectious Bronchitis ◽

Advantages And Disadvantages ◽

And Control

RNA viruses are characterized by high mutation and recombination rates, which allow a rapid adaptation to new environments. Most of the emerging diseases and host jumps are therefore sustained by these viruses. Rapid evolution may also hinder the understanding of molecular epidemiology, affect the sensitivity of diagnostic assays, limit the vaccine efficacy and favor episodes of immune escape, thus significantly complicating the control of even well-known pathogens. The history of infectious bronchitis virus (IBV) fits well with the above-mentioned scenario. Despite being known since the 1930s, it still represents one of the main causes of disease and economic losses for the poultry industry. A plethora of strategies have been developed and applied over time, with variable success, to limit its impact. However, they have rarely been evaluated objectively and on an adequate scale. Therefore, the actual advantages and disadvantages of IBV detection and control strategies, as well as their implementation, still largely depend on individual sensibility. The present manuscript aims to review the main features of IBV biology and evolution, focusing on their relevance and potential applications in terms of diagnosis and control.

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