Risk assessment of ammonia bunkering operations: Perspectives on different release scales.

Ammonia is an alternative marine fuel to reduce greenhouse gas emissions. Conducting studies on ammonia bunkering risk is essential as ammonia is toxic and corrosive to humans and the environment. This study aims to assess the ammonia bunkering operational risk from the perspectives of small, medium and large release scales. Scaling releases from small to medium results in more changes in cloud footprints at lower gas concentrations. Conversely, transitioning from medium to large releases causes more changes in cloud footprints at higher gas concentrations and lethality footprints with higher values. Moreover, this study performs a sensitivity analysis on ammonia bunkering supply, release, and meteorological factors. Wind speed is the most significant factor in small and medium releases, while hose diameter is the most significant factor in large releases. Under the given inputs, a 50% change in wind speed can have up to 100% change in the 1100 ppm maximum cloud footprint for small releases and a 663% change for medium releases. Similarly, a 50% change in hose diameter can result in a 1689% change in the 1100 ppm maximum cloud footprint for large releases. The research provides valuable insights into analysing ammonia bunkering operational risk considering different risk assessment criteria.

Accidental release of ammonia during ammonia bunkering: Dispersion behaviour under the influence of operational and weather conditions in Singapore.

Ammonia is identified as a potential marine fuel, and ammonia bunkering will take place in major bunkering ports, including Singapore. Due to its toxic nature, any accidental release of ammonia into the environment during bunkering operation has a risk of spreading rapidly and causing injury to the personnel in the vicinity and damage to the marine ecosystem. This safety study simulates how key operational parameters affect ammonia dispersion and the consequences. The results show that bunkering ammonia stored in fully-refrigerated tanks as an atmospheric pressure saturated liquid is the safest, and the severity of the consequence increases significantly with a release height of more than 5 m. A vertical release of ammonia results in the most severe consequence and shall be avoided at all times. Reducing the release duration and transfer flow rate can reduce the severity significantly. Based on the scenario used in this study, ammonia cloud disperses over a longer distance over water due to the high vaporisation rate driven by the large amount of heat generated from the dissolution of ammonia in seawater. The dispersion of ammonia over the sea spreads over a larger area during the day than at night.

Portfolio value-at-risk estimation for spot chartering decisions under changing trade patterns: A copula approach.

Evolving geopolitical relationships between countries (especially between China and the United States) in recent years have highlighted dynamically changing trade patterns across the globe, all of which elevate risk and uncertainty for transport service providers. In order to mitigate risks, shipowners and operators must be able to estimate risks appropriately; one potentially promising method of doing so is through the value-at-risk (VaR) method. VaR describes the worst loss a portfolio is likely to sustain, which will not be exceeded over a target time horizon at a given level of confidence. This article proposes a copula-based GARCH model to estimate the joint multivariate distribution, which is a key component in VaR estimation. We show that the copula model can capture the VaR more successfully, as compared with the traditional method of calculation. As an empirical study, the expected portfolio VaR is examined when a shipowner chooses among Panamax soybean trading routes under a condition of reduced trade volumes between the United States and China due to the ongoing trade turmoil. This study serves as one of the very few papers in the literature on shipping portfolio VaR analysis. The results have significant implications for shipowners regarding fleet repositioning, decision making, and risk management.

Development of indirect ELISA for the detection of canine adenovirus type 2 antibodies in dog sera

Background@#Canine adenovirus type 2 (CAV-2) induces infectious laryngotracheitis in members of the family Canidae, including dogs. To date, no ELISA kits specific for CAV-2 antibody have been commercialized for dogs in Korea. @*Objectives@#We aimed to develop new indirect enzyme-linked immunosorbent assay (I-ELISA) to perform rapid, accurate serological surveys of CAV-2 in dog serum samples. @*Methods@#In total, 165 serum samples were collected from dogs residing in Chungbuk and Gyeongbuk provinces between 2016 and 2018. The Korean CAV-2, named the APQA1701-40P strain, was propagated in Madin–Darby canine kidney cells and purified in an anion-exchange chromatography column for use as an antigen for I-ELISA. The virus-neutralizing antibody titers of CAV-2 in the dog sera were measured by virus neutralization (VN) test. @*Results@#We compared the results obtained between the VN and new I-ELISA tests. The sensitivity, specificity, and accuracy of new I-ELISA were 98.6%, 86.4% and 97.0% compared with VN test, respectively. New I-ELISA was significantly correlated with VN (r = 0.91). @*Conclusions@#These results indicate that new I-ELISA is useful for sero-surveillance of CAV-2 in dog serum.

Establishment of multiplex RT-PCR for differentiation between rabies virus with and that without mutation at position 333 of glycoprotein

Rabid raccoon dogs (Nyctereutes procyonoides koreensis) have been responsible for animal rabies in South Korea since the 1990s. A recombinant rabies vaccine strain, designated as ERAGS, was constructed for use as a bait vaccine. Therefore, new means of differentiating ERAGS from other rabies virus (RABV) strains will be required in biological manufacturing and diagnostic service centers. In this study, we designed two specific primer sets for differentiation between ERAGS and other RABVs based on mutation in the RABV glycoprotein gene. Polymerase chain reaction analysis of the glycoprotein gene revealed two DNA bands of 383 bp and 583 bp in the ERAGS strain but a single DNA band of 383 bp in the field strains. The detection limits of multiplex reverse transcription polymerase chain reaction (RT-PCR) were 80 and 8 FAID 50 /reaction for the ERAGS and Evelyn-Rokitnicki-Abelseth strains, respectively. No crossreactions were detected in the non-RABV reference viruses, including canine distemper virus, parvovirus, canine adenovirus type 1 and 2, and parainfluenza virus. The results of multiplex RT-PCR were 100% consistent with those of the fluorescent antibody test. Therefore, one-step multiplex RT-PCR is likely useful for differentiation between RABVs with and those without mutation at position 333 of the RABV glycoprotein gene.

Isolation and molecular characterizations of canine distemper virus from a naturally infected Korean dog using Vero cells expressing dog signaling lymphocyte activation molecule

Background@#Canine distemper virus (CDV) infection results in high morbidity and mortality in dogs. There has been no report about Isolation of Korean CDV since 1980 in Korea. @*Objectives@#To investigate the biological properties and the genetic characterization of Korean CDV. @*Methods@#Vero cells expressing dog signaling lymphocyte activation molecule (dSLAM) gene named as Vero/dSLAM were used to isolate CDV using 17 samples. Diagnostic methods such as cytopathic effects, immunofluorescence assay, peroxidase linked assay, electron microscopy, rapid immunodiagnostic assay, and reverse transcription polymerase chain reaction were used to confirm the Korean CDV isolate as a CDV. The genetic analysis was performed through cloning and sequencing of hemagglutinin gene of CDV isolate. @*Results@#A virus propagated in Vero/dSLAM cell was confirmed as CDV (CD1901 strain) based on the above methods. The CD1901 strain showed the highest viral titer (10 5.5 50% tissue culture infectious dose [TCID 50 ]/mL) in the Vero/dSLAM cells at 4 days post inoculation, but did not form a fork on chorioallantoic membrane of 7-day-old egg. Ribavirin, a nucleotide analogue anti-viral agent, inhibits moderately the Korean CDV propagation in the Vero/dSLAM cells. The nucleotide and amino acid sequences of the H gene of CD1901 strain were compared with those of other CDV strains. The CD1901 strain belonged to Asia 1 group and had the highest similarity (99.9%) with the BA134 strain, which was isolated in China in 2008. @*Conclusions@#We constructed successfully Vero/dSLAM and isolated one Korean CDV isolate (CD1901 strain) from a naturally infected dog. The CD1901 strain belonged to Asia 1 genotype.

Development of an Indirect ELISA Featuring Plates Coated with Column Chromatographically Purified Canine Adenovirus Type-1 Antigen

Canine adenovirus type 1 (CAV-1) causes infectious hepatitis in members of the family Canidae, including dogs. An indirect enzyme-linked immunosorbent assay (I-ELISA) that detects CAV-1 antibodies is required for large-throughput tests of dog sera. We collected 165 serum samples from dogs of Chungbuk and Gyeongbuk provinces between February 2016 and October 2018. The Korean CAV-1 vaccine strain CAV1V was propagated in Madin-Darby canine kidney (MDCK) cells and purified via Nuvia cPrime anion-exchange chromatography; the virus served as an I-ELISA antigen. Virus-neutralizing anti-CAV-1 titers in dog sera were measured using the virus neutralization (VN) method. The I-ELISA was optimized using purified CAV-1 antigen and serum samples. This kit was used to evaluate dog sera. The VN and I-ELISA data were compared. The sensitivity, specificity, and accuracy of the I-ELISA were 97.0%, 74.2%, and 92.7% compared to the VN assay, respectively. The I-ELISA data significantly correlated with those of VN (r = 0.88). These results suggest that the I-ELISA is useful for serosurveillance of CAV-1 in dog sera.