Shipping Conditions Research Articles

Quantitative assessment of the effectiveness of adaptive spatial processing algorithms in searching for low-noise underwater vehicles in surface shipping conditions of different density

The article describes the methodology and provides the results of a model quantitative assessment of the effectiveness of solving the problem of detecting and tracking a low-noise underwater object using three algorithms for spatial signal processing at the output of a multi-element antenna — the non-adaptive Bartlett algorithm, the Capon algorithm, and the Capon algorithm combined with a projection procedure limiting the signal power of strong local sources.

Isolation and Characterization of Canine Adipose-Derived Mesenchymal Stromal Cells: Considerations in Translation from Laboratory to Clinic.

In allogeneic MSC implantation, the cells are isolated from a donor different from the recipient. When tested, allogeneic MSCs have several advantages over autologous ones: faster cell growth, sufficient cell concentration, and readily available cells for clinics. To ensure the safe and efficient use of allogeneic MSCs in clinics, the MSCs need to be first tested in vitro. With this study, we paved the way by addressing the in vitro aspects of canine adipose-derived MSCs, considering the limited studies on the clinical use of canine cells. We isolated cAD-MSCs from canine falciform ligament fat and evaluated their viability and proliferation using an MTS assay. Then, we characterized the MSC-specific antigens using immunophenotyping and immunofluorescence and demonstrated their potential for in vitro differentiation. Moreover, we established shipping and cryobanking procedures to lead the study to become an off-the-shelf therapy. During expansion, the cells demonstrated a linear increase in cell numbers, confirming their proliferation quantitatively. The cells showed viability before and after cryopreservation, demonstrating that cell viability can be preserved. From a clinical perspective, the established shipping conditions demonstrated that the cells retain their viability for up to 48 h. This study lays the groundwork for the potential use of allogeneic cAD-MSCs in clinical applications.

Enhancing Information Exchange in Ship Maintenance through Digital Twins and IoT: A Comprehensive Framework

This article proposes a comprehensive framework for enhancing information exchange in ship maintenance through the integration of Digital Twins (DTs) and the Internet of Things (IoT). The maritime industry faces significant challenges in maintaining ships due to issues like data silos, delayed information flow, and insufficient real-time updates. By leveraging advanced technologies such as DTs and IoT, this framework aims to optimize maintenance processes, improve decision-making, and increase the operational efficiency of maritime vessels. Digital Twins create virtual replicas of physical assets, allowing for continuous monitoring, simulation, and prediction of ship conditions. Meanwhile, IoT devices enable real-time data collection and transmission from various ship components, facilitating a seamless flow of information. This integrated approach enhances predictive maintenance capabilities, reduces downtime, and improves resource allocation. The article will delve into the architecture of the proposed framework, implementation steps, and potential challenges, supported by case studies that demonstrate its practical application and benefits. By addressing these aspects, the framework aims to provide a robust solution for modernizing ship maintenance operations and ensuring the longevity and reliability of maritime assets.

A fuzzy evidential reasoning-based approach for assessing the navigation obstruction risk of shipwrecks in the Yangtze river

ABSTRACT This paper aims to evaluate the navigation obstruction risk represented by shipwrecks in shallow waters based on a fuzzy evidential reasoning approach. The purpose of this approach is to establish a hierarchical decision-making framework that considers ship conditions, traffic environment, distance from sensitive areas, and natural environment; to derive the belief rule base using the IF-THEN rule with a belief structure; and to obtain the crisp values of navigation obstruction risk of shipwrecks via evidential reasoning. This approach is applied to the navigation obstruction risk assessment of 10 historical shipwrecks in the Yangtze River, and the evaluation results are consistent with historical data. Consequently, this approach can be used for assisting in shipwreck salvage decision-making in navigable waters.

An insight about roll damping within the second generation intact stability criteria

AbstractDespite the recognized complexity to estimate the damping influence on ship roll motion, some efficient semi-empirical methodologies have been developed along the years to this purpose. CFD methods, in principle the most appropriate tools to predict roll damping, are not a favorite option in preliminary design at present due to their implications in terms of complexity and computational time. In this paper, an integration of the semi-empirical Ikeda’s simplified method has been formulated with modification of the bilge keels and lift components, following a contribution found in the literature and relevant for Ro–Ro ships. Moreover, with focus on damping evaluation, the second generation intact stability criteria (SGISc) have been investigated: the second-level vulnerability criteria for dead ship condition and parametric roll have been applied to a Ro–Ro passenger ship. Both the consolidated and the new proposed roll damping prediction methods have been implemented in order to appreciate their effects on the final outcome.

A Study on the Mast Structure Vibration Limits considering the Operating Time of Naval Ships

The mast structure of a naval ship has a lot of expensive equipment attached and is easily exposed to strong vibration due to its structural characteristics, so it is necessary to manage vibrations well to prevent equipment failure and increase operating time. Since September 2015, the Navy has been managing the vibration of the ship's mast structure with a separate tolerance standard from the local vibration, but this standard is set at 1/2 of the vibration limits for mast-mounted equipment without any engineering basis. So the establishment of new vibration limits based on the operating conditions of naval ships is required. In this study, the mast structure vibration limits were reviewed considering the actual operating time of naval ships, and the results were compared with the standards of major overseas classification societies and the actual measurements of a ship that had mast structure vibration problems.

A-271 Expansion of sample viability for self-collected urine specimens containing CT/NG & TV/MG utilizing the Roche cobas® 6800 System

Abstract Background The CDC estimates that 1 in 5 Americans have an STI. Home collection for STIs could help mitigate the stigma, cost, and accessibility, which contribute to low diagnosis rates and disparities in diagnosis and treatment. Home self-collected specimens occasionally arrive in the lab with volumes higher or lower than what is required by the assay manufacturer’s specifications for self-collection. This study demonstrates that sample stability is retained after temperature fluctuation via shipping - even when the correct ratio of buffer to sample has been disturbed, a precise and accurate measurement persists. Our goal is to improve accessibility to discreet, patient collected STI tests. Methods Positive samples were prepared by spiking negative urine with organisms near the manufacturer’s limit of detection (LoD). Properly collected samples were aliquoted into tubes with 5mL volumes as per manufacturer specifications. Improperly collected samples were either overfilled (9mL for CT/NG, 7mL for TV/MG) or underfilled (1mL for CT/NG, 2mL for TV/MG). Samples underwent temperature cycling to mimic summer or winter shipping conditions. Ambient temperature studies were conducted on over/underfilled specimens. All samples were baseline tested and compared qualitatively to the manufacturer's claimed LoD using the Roche c6800 and the IVD assays for CT/NG & TV/MG. Results Improperly filled samples were stable at ambient temperature for 63 days for CT/NG, and 59 days for TV/MG. See chart for temperature cycling results. All samples (n=164) showed 100% qualitative agreement with their baseline result after summer and winter shipping challenges. Conclusions Urine samples that fail to satisfy the manufacturer’s self-collection specifications or have endured temperature fluctuations still yield accurate CT/NG & TV/MG results. These results indicate the potential to enhance sample viability and patient accessibility utilizing validated IVD assays.

A-225 Validation of self-collected capillary dried plasma spot collection for lipoprotein(a) testing

Abstract Background Cardiovascular disease is prominent among socially disadvantaged populations that do not have the resources for standard health screening. Self-collected capillary Advance Dx (ADX) dried plasma spot cards could address these issues by offering access to clinically acceptable lipid screening from remote collections. Our laboratory currently uses ADX specimens to screen for cholesterol, calculated LDL, HDL, glucose, lipoprotein (a) (LP(a)), and triglycerides, however, the current study will focus on the validation of self-collected capillary ADX specimens for LP(a) testing. Methods ADX LP(a) was measured using the Tina-quant Lipoprotein (a) Gen.2 assay on the Roche cobas c702 closed development channel. All closed development channel assay parameters followed the standard assay, except sample volume increased from 2 to 18uL. Calibration was performed using Roche LP(a) calibrators diluted 1:10 with water. Patient specimens were prepared by collecting four 6mm punches from the plasma portion of the ADX card. Samples were resuspended in 400uL of 0.1% bovine serum albumin and incubated for 30 minutes at room temperature (RT) while shaking at 250 RPM. Non-biological materials were diluted 1:13 with water to match the sample-to-diluent ratio of the extracted patient ADX specimens. A correction factor (CF) was derived and challenged using total protein (TP) as an internal standard. BioRad Lipids Control (BRLC) and ADX patient specimens were run for wet and dry matrices to establish imprecision. Accuracy was determined using BRLC and ADX patient specimens. Linearity was confirmed by running 5 levels of Maine Standards Linearity Cardiac CM3 Kit. ADX stability was observed at RT and under summer/winter conditions to account for shipping to the laboratory. Results Specimens tested between venous and ADX LP(a) to derive the CF (n=70) had a bias of 21.92 mg/dL (132.28%) and a linear equation of (y=2.40x -1.23; R=0.985). Average card TP was 4.36 g/dL. The resulting CF is: reported ADX LP(a) = ((4.36/card TP)*card LP(a)*2.397)-1.23. Matched venous and ADX specimens that challenged the CF (n=50) had a bias of -1.00 mg/dL (-3.33%) and a linear equation of (y=0.98x -0.25; R=0.994) at the medical decision point of 30.00 mg/dL. Imprecision was 2.4% and 2.4% for BRLC specimens with mean concentrations of 15.04 and 29.40 mg/dL, respectively. Imprecision was 4.2% and 10.5% for ADX patient control specimens with mean venous target concentrations of 66.85 and 14.81 mg/dL, respectively. BRLC had an average bias of -0.31 mg/dL (-2.03%) and 0.41 mg/dL (1.40%) for levels 1 and 2, respectively. ADX patient specimens (n=3) had average biases of -1.47 mg/dL (-3.83%), 1.43 mg/dL (2.15%), and -1.58 mg/dL (-10.64%). ADX LP(a) concentrations from 6.0-80.0 mg/dL were linear (y=1.04x -0.45; R=0.999). The ADX specimen is stable for at least 7 days at RT and at least 5 days under summer and winter shipping conditions. Conclusions All assay parameters met acceptability criteria and were less than the total allowable error of 28.8%. Self-collected capillary ADX specimens are acceptable for the clinical measurement of LP(a), and effectively improve access to testing and identifying high-risk individuals as therapeutic strategies for treatment of elevated LP(a) continue to emerge.

Particle formation in response to different protein formulations and containers: Insights from machine learning analysis of particle images

Subvisible particle count is a biotherapeutics stability indicator widely used by pharmaceutical industries. A variety of stresses that biotherapeutics are exposed to during development can impact particle morphology. By classifying particle morphological differences, stresses that have been applied to monoclonal antibodies (mAbs) can be identified. This study aims to evaluate common biotherapeutic drug storage and shipment conditions that are known to impact protein aggregation. Two different studies were conducted to capture particle images using micro-flow imaging and to classify particles using a convolutional neural network. The first study evaluated particles produced in response to agitation, heat, and freeze-thaw stresses in one mAb formulated in five different formulations. The second study evaluated particles from two common drug containers, a high-density polyethylene bottle and a glass vial, in six mAbs exposed solely to agitation stress. An extension of this study was also conducted to evaluate the impact of sequential stress exposure compared to exposure to one stress alone, on particle morphology. Overall, the convolutional neural network was able to classify particles belonging to a particular formulation or container. These studies indicate that storage and shipping stresses can impact particle morphology according to formulation composition and mAb.

Implementation of Indonesian Flag for Electricity Standards on Non-Conventional Vessel at Palipi Harbor

This research aims to analyze the current level of application of electricity standards on Indonesian-flagged non-convention ships by Gross Tonnage (GT 7-35), identify the obstacles faced in implementing electricity standards on Indonesian-flag non-convention ships by Gross Tonnage (GT 7-35) and how to make efforts in increasing the application of electrical standards on Indonesian-flagged non-convention ships by Gross Tonnage (GT 7-35). The research method used is a qualitative method with data collection techniques involving observation, documentation, and interviews with related parties. The data analysis technique used is qualitative descriptive analysis. The results show that the electrical condition of non-convention ships varies greatly depending on factors such as ship type, ship size, and the level of maintenance performed. The constraints faced in the implementation of electrical standards on Indonesian-flagged non-convention ships by Gross Tonnage (GT 7-35) are limited resources, understanding and awareness, changes in technology and regulations, and lack of routine maintenance and inspections; and collaboration between authorities, ship owners, and ship crews has not been maximized in the implementation of electrical standards, as well as the absence of training programs or resources offered by related parties to improve understanding and skills related to ship electricity.

Shipment of Glycerolized RBC Segments for Red Cell Concentrate Compatibility Testing.

Background: Red cell concentrate (RCC) cryopreservation allows for long-term storage of RCCs with rare phenotypes. Currently, tubing segments are not produced for these frozen units. Pre-transfusion compatibility testing therefore requires thawing and deglycerolization of the whole unit. A study was conducted to demonstrate the feasibility of using segments for compatibility testing, including circumstances where segments would require shipment to a reference laboratory. Study Design and Methods: RCCs produced using the red cell filtration method from citrate-phosphate-dextrose whole blood collections were glycerolized (40%) at day 21 post-collection and segments were generated prior to freezing. Room temperature (RT, 18°C-20°C) or water bath (WB, 37°C) thawing of segments was performed prior to storage at RT or at refrigerated temperatures (cold, 1°C -6°C) for 0, 24, 48, or 72 hours followed by deglycerolization and hemolysis testing. Additional segments were thawed and shipped in temperature-controlled containers at either RT or 1°C -10°C for antibody screening. Results: Hemolysis and RBC recovery results did not show significant differences over the storage period or between thawing and storage conditions. RBC recovery ranged from 46% to 64%. Hemoglobin (Hb) recovery ranged from 56% to 96%; for RT-thawed segments, recovery was significantly higher at 24 hours and lower at 72 hours for RT storage compared with cold storage. WB-thawed, cold-stored segments had higher Hb recoveries at 48 hours. Phenotype assessment was successful for all segments regardless of thawing method or shipping condition. Discussion: The shipment of thawed segments containing glycerolized red cells is feasible for the purpose of conducting pretransfusion phenotype evaluations or pretransfusion compatibility checks.

Experimental assessment of hull, propeller, and the gate rudder system interaction in calm water and oblique waves

This study focuses on the experimental assessment of the EU H2020 Innovation Action project GATERS' target ship, a 7241 DWT multi-purpose dry cargo ship (M/V ERGE), scaled to 1/27.1, in calm water and oblique wave (at a yaw angle of the ship model) conditions. M/V ERGE was initially built with a Conventional Rudder System (CRS) in 2010 but was later retrofitted with a newly introduced energy-saving device, the Gate Rudder System (GRS), in 2023 as part of the GATERS project. In this project, the interaction of the GRS with the hull and propeller was investigated using model tests of the vessel in the Kelvin Hydrodynamics Laboratory's (KHL) towing tank at the University of Strathclyde (UoS) and compared to the CRS. The main objectives of these tests were threefold. While they aimed to make experimental contributions toward the establishment of the best procedure for estimating the powering prediction of a ship with the GRS, they also aimed to investigate the hull, propeller and rudder interaction for the CRS and GRS configurations. In addition, a set of comparative pilot tests were conducted in waves to explore the effect of the oblique waves on the vessel's performance with the CRS and GRS. The resistance and self-propulsion tests were performed for both the CRS and GRS configurations, and performance predictions based on the model tests were compared with sea trials. Furthermore, tests at a yaw angle of the ship model were conducted to evaluate the effect of waves on the vessel's performance with the CRS and GRS, simulating the in-service conditions of commercial ships. These tests were conducted in regular waves with the hull at a yaw angle to simulate oblique wave conditions, with a wave height of 1.25 m in full scale (corresponding to moderate breeze, Beaufort 4) for a range of wavelengths. Numerical analyses were performed to obtain the full-scale propeller open water characteristics. The paper demonstrates the superior interaction of the GRS with the hull and propeller in both conditions compared to the CRS configuration, even improving its contribution to the vessel's performance in oblique waves.

Your Blood is Out for Delivery: Considerations of Shipping Time and Temperature on Degradation of RNA from Stabilized Whole Blood.

Remote research studies are an invaluable tool for reaching populations in geographical regions with limited access to large medical centers or universities. To expand the remote study toolkit, we have previously developed homeRNA, which allows for at-home self-collection and stabilization of blood and demonstrated the feasibility of using homeRNA in high temperature climates. Here, we expand upon this work through a systematic study exploring the effects of high temperature on RNA integrity through in-lab and field experiments. Compared to the frozen controls (overall mean RIN of 8.2, n = 8), samples kept at 37°C for 2, 4, and 8 days had mean RINs of 7.6, 5.9, and 5.2 (n = 3), respectively, indicating that typical shipping conditions (~2 days) yield samples suitable for downstream RNA sequencing. Shorter time intervals (6 hours) resulted in minimal RNA degradation (median RIN of 6.4, n = 3) even at higher temperatures (50°C) compared to the frozen control (mean RIN of 7.8, n = 3). Additionally, we shipped homeRNA-stabilized blood from a single donor to 14 different states and back during the summer with continuous temperature probes (7.1 median RIN, n = 42). Samples from all locations were analyzed with 3' mRNA-seq to assess differences in gene counts, with the transcriptomic data suggesting that there was no preferential degradation of transcripts as a result of different shipping times, temperatures, and regions. Overall, our data support that homeRNA can be used in elevated temperature conditions, enabling decentralized sample collection for telemedicine, global health, and clinical research.

PrecivityAD2™ Blood Test: Analytical Validation of an LC-MS/MS Assay for Quantifying Plasma Phospho-tau217 and Non-Phospho-tau217 Peptide Concentrations That Are Used with Plasma Amyloid-β42/40 in a Multianalyte Assay with Algorithmic Analysis for Detecting Brain Amyloid Pathology.

Alzheimer's disease (AD) is a progressive irreversible neurodegenerative disorder that represents a major global public health concern. Traditionally, AD is diagnosed using cerebrospinal fluid biomarker analysis or brain imaging modalities. Recently, less burdensome, more widely available blood biomarker (BBM) assays for amyloid-beta (Aβ42/40) and phosphorylated-tau concentrations have been found to accurately identify the presence/absence of brain amyloid plaques and tau tangles and have helped to streamline AD diagnosis. However, few BBMs have been rigorously analytically validated. Herein, we report the analytical validation of a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) multiplex method for quantifying plasma phosphorylated-tau217 (p-tau217) and non-phosphorylated-tau217 (np-tau217) peptide concentrations. We combined the p-tau217/np-tau217 concentrations ratio (%p-tau217) and the previously validated LC-MS/MS multiplex assay for plasma Aβ42/40 into a new multianalyte assay with algorithmic analysis (MAAA; PrecivityAD2™ test) that identifies brain amyloid status based on brain amyloid positron emission tomography. We found (a) the %p-tau217 assay is precise, accurate, sensitive, and linear over a wide analytical measurement range, and free from carryover and interference; (b) the pre-analytical specimen collection, processing, storage, and shipping conditions that maintain plasma tau peptide stability; and (c) using the measured analytical imprecision for plasma Aβ42/40 and p-tau217/np-tau217 levels in a worst-case scenario model, the PrecivityAD2 test algorithm for amyloid pathology classification changed for only 3.5% of participants from brain amyloid positive to negative, or from negative to positive. The plasma sample preparation and LC-MS/MS methods underlying the PrecivityAD2 test are suitable for use in the clinical laboratory and valid for the test's intended purpose: to aid in the diagnostic evaluation of individuals aged 55 and older with signs or symptoms of mild cognitive impairment or dementia.

Comparative study of electric power structure of hydrogen fuel cell electric propulsion ship system

Abstract Aiming at the problem of the applicability of active and semi-active structures of hybrid energy storage units to the complex working conditions of ships in the hydrogen fuel cell electric propulsion system of ships, a comparative study of such structures is carried out in terms of the control strategy, capacity design and optimization effect, respectively. The hybrid energy storage unit in the active structure, supercapacitor and battery, are both connected to the DC bus through the converter. In the hybrid energy storage unit in the semi-active structure, the battery is connected to the low-voltage DC bus through the converter flow in parallel with the supercapacitor, and then connected to the DC bus through the converter. Two kinds of hydrogen fuel cell electric propulsion ship system topology simulation models were established by MATLAB/Simulink respectively, and simulation verification was carried out. The simulation results show that the hybrid energy storage unit with an active structure has stronger adaptability in complex working conditions during ship operation.

The Efforts to Improve the Seaworthiness at the Port Authority and Harbourmaster Office (KSOP) of Bima Class IV

Seaworthiness is essential because it impacts maritime operations' safety, efficiency, and sustainability. Therefore, the Harbormaster and Port Authority Office (KSOP) ensures ship seaworthiness to maintain naval safety, protect the environment, and ensure smooth port operations. The research employed a descriptive qualitative method to investigate and describe a phenomenon. The data was obtained by observation and a deep literature review of the problems discussed. The research found that: 1) several problems that often arise regarding ship seaworthiness are the ship's technical condition, management and operations, environmental factors, compliance with regulations, market conditions, and competition. 2) efforts to improve seaworthiness carried out by KSOP Bima are routine inspections and certification, increasing human resources, operational supervision, developing port infrastructure, applying advanced technology, collaborating and coordinating with related agencies, strict law enforcement, education, and outreach, and developing emergency procedures. 3) The security and safety conditions of ships entering and leaving the Bima Port KSOP require continued attention and effort. From this study, they implement strict regulations, use advanced technology, improve infrastructure, conduct continuous training, and collaborate strongly with related agencies. KSOP Bima can ensure that ships operating in its area meet seaworthiness standards, supporting safe and efficient port operations.

From Bed to Bench: Pre-analytical Stability of 29 Anti-infective Agents in Plasma and Whole Blood to Improve Accuracy of Therapeutic Drug Monitoring.

Therapeutic drug monitoring requires a validated assay and appropriate conditions for sample shipment and storage based on the stability of the compound to be analyzed. This study evaluated the stability of 29 antimicrobial compounds in whole blood (WB) and plasma samples under various storage conditions. The pre-analytical stability of 22 antibiotics (amoxicillin, aztreonam, cefazolin, cefepime, cefotaxime, cefoxitin, ceftazidime, ceftobiprole, ceftolozane, ceftriaxone, ciprofloxacin, clindamycin, cloxacillin, daptomycin, levofloxacin, linezolid, meropenem, metronidazole, moxifloxacin, piperacillin, sulfamethoxazole, and trimethoprim), 2 beta-lactamase inhibitors (avibactam, tazobactam), and 5 antituberculosis drugs (ethambutol, isoniazid, pyrazinamide, rifabutin, and rifampicin) was assessed by WB for up to 24 hours at room temperature (RT) and 72 hours at +4°C. The stability in plasma was evaluated for up to 6 hours at RT, 24 hours at +4°C, 1 month at -20°C, and 6 months at -80°C. Concerning WB stability, all investigated compounds were stable for 24 hours at RT, except meropenem and isoniazid, which were stable for 6 hours; however, for 24 hours at +4°C, all the compounds were stable. For storage durations of 48 and 72 hours at +4°C, all compounds were stable, except for ciprofloxacin, cotrimoxazole, and isoniazid. Concerning stability in plasma, all compounds were stable for 6 hours at RT, and all except isoniazid were stable for 24 hours at +4°C. All the tested compounds were stable for 7 days at -20°C, except isoniazid, for which a degradation of approximately 20% was observed. An important degradation was observed for beta-lactam antibiotics after 1 month at -20°C. All compounds were stable at -80°C for 6 months. The pre-analytical stabilities of several anti-infective compounds was described. The present results can be used to determine the appropriate conditions for shipping and storing samples dedicated to therapeutic drug monitoring of the investigated compounds.

Odor-Cued Grab Air Sampling for Improved Investigative Odorant Prioritization Assessment of Transient Downwind Environmental Odor Events.

A critical prelude to any community odor assessment should be the prioritization of specific chemical odorants that are most responsible for targeted downwind odors. Unfortunately, and historically, this is a step that has often been bypassed or overlooked. However, correct understanding of the specific impactful volatile organic compounds (VOCs) can inform the follow-on sampling, analytical, and remediation strategies that are most appropriate and efficient, based upon the chemistry behind the issue. With this understanding, the techniques and sampling strategies presented herein should be viewed as a qualitative prelude rather than an addendum to a follow-up routine, automated downwind odor monitoring. Downwind odor characteristics can vary depending upon the size of the upwind source, interim topography, and wind conditions. At one extreme, the downwind odor plume from a relatively large source located on a flat open plain and under stable, near-straight line wind conditions can be rather broad, sustained, and predictable. In contrast, the plume from a small point source (e.g., a roof vent stack) located on irregular topography and under rapidly shifting wind conditions can be intermittent and fleeting ("spikes" or "bursts"). These transient odor events can be surprisingly intense and offensive, despite their fleeting occurrence and perception. This work reports on improving and optimizing an environmental sampling strategy for odorant prioritization from such transient downwind odor conditions. This optimization addresses the challenges of (1) sampling of transient odor "spikes" and (2) prioritizing odors/odorants from multiple, closely colocated point sources under transient event conditions. Prioritizing is defined as identifying the key impactful odorants downwind. Grab air sampling protocol refinement has emerged from actual community environmental odor assessment projects. The challenge of assessing transient odor events has been mitigated by utilizing (a) rapid, odor-cued whole-air grab sampling (i.e., activated by and synchronous with the perceived sensory spikes) into metalized fluorinated ethylene polymer (m-FEP) gas sampling bags; (b) immediate transfer from bags onto solid-phase microextraction (SPME) fibers or sorbent tubes; and (c) maintaining refrigerated storage and shipment conditions between field collection and in-laboratory analysis. Results demonstrated approximately 11-fold increases in target odorant yields for 900 mL air sample capture on sorbent tube transfers from 2 to 3 s "burst" odor event bag captures compared to equivalent direct collections (with sorbent tubes) at the same downwind receptor location but during perceived (stable) odor "lull" periods. An application targeting general odor sampling and point-source differentiation utilizing tracer gases is also presented.

Ship collision risk assessment: A multi-criteria decision-making framework based on Dempster–Shafer evidence theory

Ship collision risk modelling is dominated by the utilization of the experts’ experiential insights and knowledge. To construct an effective assessment model for evaluating potential ship collision risks grounded in expert judgments, this paper introduces a novel multi-criteria decision-making framework based on Dempster–Shafer evidence theory (DSET). Firstly, a novel index-based assessment system is provided to generate the potential collision risk value of ships based on automatic identification system (AIS) data, which encompasses ship condition parameters, deviation coefficient, and frequency coefficient. Further, to generate the weights of these indicators, a framework to extract expert opinions is provided, which includes two parts: a) converting experts’ opinions into D-S framework through hesitant fuzzy linguistic terms and b) generating experts’ opinions using improved DSET. Regarding part a, a methodology is proposed to evaluate the trustworthiness of experts by considering both the level of uncertainty in their opinions and the degree of similarity between their viewpoints. Concerning part b, strategies are integrated to ascertain the most suitable weight for the basic probability assignment, thereby mitigating conflicts within the evidence. Finally, based on the collected AIS data, the proposed framework has been applied to six of the world's busiest waterways: (1) the Strait of Malacca, (2) the English Channel, (3) the Panama Canal, (4) the Suez Canal, (5) the Danish Straits, and (6) the Strait of Hormuz. Subsequently, comprehensive analytical results and recommendations are furnished, such as wide and smooth channels showing elevated risk.

Quantitative Assessment of the Efficiency of Adaptive Spatial Processing Algorithms in Detecting and Tracking the Low-Noise Underwater Vehicles in Various Shipping Conditions

Quantitative Assessment of the Efficiency of Adaptive Spatial Processing Algorithms in Detecting and Tracking the Low-Noise Underwater Vehicles in Various Shipping Conditions