Applications of holistic ship theory for the simulation driven optimization of the design and operation of large bulk carriers

The change of scenery in shipping has been evident over the past 20 years. The changing fuel costs, tough and volatile market conditions, the constant societal pressure for a «green» environmental footprint combined with ever demanding international safety regulations create the new framework in which commercial ship designs are subject to. As a result of this current status of shipping commercial a change of attitude in the philosophy and process of ship design is required in order to shift towards new approaches where holistic approaches are deemed necessary. Apart from considering all the interrelationships between the subsystems that consist the vessel lifecycle and supply chain considerations are the key in successful and «operator oriented» designs. The methodology herein presented is built within the computer aided engineering (CAE) software CAESES that integrates in the design process CFD codes. It can be successfully used for the optimization of either of the basic design of a vessel or the operation of an existing vessel with regards to the maximization of the efficiency, safety and competitiveness of the final design. The model is created based on the design of a large bulk carrier and a simulation model consisting of modules that cover most aspects of ship design. Stability, strength, powering and propulsion, safety, economics, operational and maintenance and in service management considerations are tightly integrated within a fully parametric model. This tight integration enables the user to simulate the response of the model in variations of the geometrical, design variables of the vessel (including its propeller) under conditions of simulation and uncertainty. The uncertainty modelling is extensive and in several levels including but not limited to Economic, Environmental, and Operational uncertainty as well an accuracy modelling of the methodology itself

Optimisation of Offshore Wind Farms Using a Genetic Algorithm

A modular framework for the optimisation of an offshore wind farm using a discrete genetic algorithm is presented. This approach uses a bespoke grid generation algorithm to define the discrete positions that turbines may occupy thereby implicitly satisfying navigational and search and rescue constraints through the wind farm. The presented methodology takes a holistic approach optimising both the turbine placement and inter-array cable network, while minimising the levelised cost of energy and satisfying real world constraints. This tool therefore integrates models for the assessment of the energy production including wake losses; the optimisation of the inter-array cables; and the estimation of costs of the project over the lifetime. This framework will allow alternate approaches to wake and cost modelling as well as optimisation to be benchmarked in the future

Offshore Wind Farm Electrical Cable Layout Optimization

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.This article explores an automated approach for the efficient placement of substations and the design of an inter-array electrical collection network for an offshore wind farm through the minimization of the cost. To accomplish this, the problem is represented as a number of sub-problems that are solved in series using a combination of heuristic algorithms. The overall problem is first solved by clustering the turbines to generate valid substation positions. From this, a navigational mesh pathfinding algorithm based on Delaunay triangulation is applied to identify valid cable paths, which are then used in a mixed-integer linear programming problem to solve for a constrained capacitated minimum spanning tree considering all realistic constraints. The final tree that is produced represents the solution to the inter-array cable problem. This method is applied to a planned wind farm to illustrate the suitability of the approach and the resulting layout that is generated

Wake interference of two identical oscillating cylinders in tandem: An experimental study

This study aims to assess the impact of the spacing between cylinders on their dynamic behaviour. Observations during this experiment have helped to identify the effect of spacing on excitation mechanism of each cylinder as well as establishing the relationship between cylinders response and the spacing between them. Arrays of cylindrical Structures in close proximity are common in variety of engineering structures, particularly in the off-shore industry. If the cylinders are flexible, and are subject to excitation from fluid flow, then the dynamics is influenced by complex interactions between the cylinders, dependent on a variety of parameters. Two cylinders were flexibly mounted in tandem at different spacings from 20D to 3.5D and were towed at different Reynolds numbers ranging from 8.7× 10^3 to 5.2 ×10^4. The gap between cylinders was set to 20, 15, 10, 8, 5, 4, 3.5D respectively; the responses of the cylinders were measured and the mutual interactions were compared. The two cylinders were identical and free to oscillate in both cross-flow and stream-wise directions. The validity of results was examined by comparing to available data in literature and results attained by testing cylinders in-dependently in the towing tank.The interaction of two cylinders are studied through frequency analysis of both cylinders response motion to determine how upstream vortices impact the trailing cylinder response in stream-wise and cross-flow differently.It was observed that leading and trailing cylinders oscillate at different frequencies which is in contrast with results obtained from two fixed cylinders in tandem where both cylinders oscillate at the same frequency.Additionally, it is discussed how spacing controls the excitation mechanism

Calm water resistance and self propulsion simulations including cavitation for an LNG carrier in extreme trim conditions

In recent years many studies and real-life applications dealing with trim optimisation have shown that operating a ship at small trim angles can improve the energy efficiency by up to 5% depending on ship speeds and loading conditions. This efficiency gain mainly results from the re-positioning of underwater hull features, such as the bulbous bow or the stern bulb. Different to the above described approach the present study deals with operating a LNG Carrier at an extreme bow-up trim angle of Ɵ = −1.9 deg. In order to predict the performance, URANS virtual towing tank simulations in calm water were performed for both, nominal resistance conditions and self-propulsion conditions including cavitation. The numerical results, including the ship resistance, the nominal propeller wake field and the simulation of propeller cavitation in self-propulsion conditions indicated a largely improved performance. Due to a significant reduction in nominal resistance by up to 27.5% the ship selfpropulsion point in extreme trim conditions was found at a lower propeller rotation rate compared to level trim conditions. This also reduced the cavitation volume and finally resulted in a delivered power reduction of up to 28.8%

Immune checkpoint inhibitor-induced subacute cutaneous lupus erythematosus: a case report and review of the literature

Immune checkpoint inhibitor (ICI) use has been associated with numerous autoimmune side effects, known as immune related adverse events (irAEs). Cutaneous irAEs are common and affect up to 50% of patients treated with ICIs. There have been an increasing number of cases reported in the literature regarding ICI-induced subacute cutaneous lupus erythematosus (SCLE). ICI-induced SCLE is important to recognize as it can result in a delayed and/or prolonged skin reaction despite treatment discontinuation. We describe a patient with gastro-esophageal adenocarcinoma who developed SCLE following one cycle of nivolumab treatment. A 75-year-old man presented to our clinic with a new photo-distributed rash composed of oval scaly pink papules and plaques involving his chest and arms. Despite treatment with topical corticosteroids, he presented to the emergency department 1 week later with worsening rash. Skin biopsy showed vacuolar interface pattern, along with superficial perivascular lymphocytic infiltrate, consistent with a drug eruption. The clinicopathological presentation was consistent with ICI-induced SCLE. Nivolumab treatment was discontinued due to the severity of the rash. The rash remitted with systemic corticosteroids, high potency topical steroids, and hydroxychloroquine. Unfortunately, the patient developed intraperitoneal metastatic disease, and was enrolled in hospice care. In this paper, we highlight the importance of early identification and treatment of this irAE. A review of the literature, including a discussion on the management of ICI-induced SCLE is also provided

Recombinant activated factor VII in a patient with intracranial hemorrhage and severe thrombocytopenia.

Hemorrhage in patients with hematologic malignancies is often difficult to manage as many of these patients also have coagulopathy and thrombocytopenia of varying severity. Recombinant factor VIIa is a FDA-approved agent for management of bleeding in hemophilia patients with inhibitors. Use of recombinant FVIIa has also been used as a last resort in various clinical settings such as trauma, alveolar hemorrhage, gastrointestinal bleeding, and intracranial hemorrhage for control of bleeding with variable outcomes. This paper presents a case of recombinant FVIIa administration in a patient with multiple myeloma and profound transfusion refractory thrombocytopenia suffering from traumatic subdural hematoma

First Steps toward a Multi-Parameter Optimisation Tool for Floating Tidal Platforms – Assessment of an LCoE-Based Site Selection Methodology

This is the author accepted manuscript. The final version is available from EWTEC via the link in this record.The aim of this paper is assess and alter the method of tidal stream site selection, so as to ensure deployments are commercially viable. This paper has demonstrated the inter-site variability of LCoE, and that deploying in higher flow speed locations is not necessarily favourable if the site is exposed to harsh environmental conditions, despite potentially having higher yield. Neglecting to investigate the impact of MET-Ocean characteristics can lead to underestimation of the associated costs of an exposed site by up to 48%. For a sheltered site, however, current methods of site assessment generally used by the tidal stream industry are acceptable. When comparing the two types of site, taking into account the effects of MET-Ocean conditions indicates that the LCoE of a sheltered low flow site can be 75% lower than an exposed higher flow site over a 20yr PLAT-I deploymen

Transient left ventricular dysfunction following chimeric antigen receptor T-cell-mediated encephalopathy: A form of stress cardiomyopathy.

Chimeric antigen receptor (CAR) T-cell therapy represents a new strategy in treating lymphoid malignancies, such as relapsed-refractory diffuse large B-cell lymphoma (DLBCL). Several toxicities including cytokine release syndrome (CRS), neurotoxicity, and cardiovascular toxicity have been linked to CAR T-cell therapy. Transient impairment in left ventricular systolic function is described after CAR-T, however, the mechanism remains poorly understood. This paper reports the clinical presentation and outcome of two patients with relapsed-refractory DLBCL who experienced encephalopathy and CRS following CAR T-cell therapy and developed transient left ventricular dysfunction consistent with stress cardiomyopathy