Combined numerical and experimental simulations of unsteady ship airwakes

Abstract To aid pilot training for shipboard helicopter operations, computational fluid dynamics (CFD) is increasingly being performed to model ship airwakes. The calculated velocity field data are exported to the flight simulator as look-up tables. In the Canadian context, work to expand ship airwake simulation capabilities for future use in flight simulators is currently being done using the open-source OpenFOAM. The current paper reports on the progress of this work using the simple frigate shape 2 (SFS2), which is a highly simplified ship geometry, to validate the method for low-sea-state (also referenced to as static) cases. By employing delayed detached eddy simulations (DDES), OpenFOAM was able to compute the unsteady ship airwakes well compared to experimental data and other references. After validation, OpenFOAM was applied to the Canadian Patrol Frigate (CPF), a more representative example of a naval vessel. Hybrid structured and unstructured grids were used because of the complexity of the CPF geometry. The agreement between the computed and the experimental results for the static CPF was reasonable, which built a solid foundation supporting further development of simulation for the CPF in motion

Ship anemometer bias management

Abstract Wind measurements made on ships are used for general navigation, maritime operations, and in some cases logged to support oceanographic research. They are particularly important for aircraft-carrying ships as operations can be restricted in certain wind conditions. Shipboard wind measurements are subject to biases and inaccuracies as a result of air flow changing as it passes over and around the ship, its structures, and features. Ship-induced wind distortion and the resulting bias on anemometer readings can range from insignificant to severe. Anemometer bias cannot be completely eliminated for all conditions, but it can be managed so that reliable and accurate assessments of wind at sea can be identified. This paper describes the basic concepts related to ship wind distortion along with procedures and considerations on how bias can be quantified using simulations or model tests and validated using sea trials. An example case of a helicopter-carrying frigate is used to demonstrate the process of quantifying bias, calculating metrics, determining useful ranges, and developing and applying correction-functions. Wind tunnel measurements and a sea trial successfully demonstrated and validated the proposed ship anemometer bias management methodology

Matrix-Bound Growth Factors are Released upon Cartilage Compression by an Aggrecan-Dependent Sodium Flux that is Lost in Osteoarthritis

Articular cartilage is a dense extracellular matrix-rich tissue that degrades following chronic mechanical stress, resulting in osteoarthritis (OA). The tissue has low intrinsic repair especially in aged and osteoarthritic joints. Here, we describe three pro-regenerative factors; fibroblast growth factor 2 (FGF2), connective tissue growth factor, bound to transforming growth factor-beta (CTGF-TGFβ), and hepatoma-derived growth factor (HDGF), that are rapidly released from the pericellular matrix (PCM) of articular cartilage upon mechanical injury. All three growth factors bound heparan sulfate, and were displaced by exogenous NaCl. We hypothesised that sodium, sequestered within the aggrecan-rich matrix, was freed by injurious compression, thereby enhancing the bioavailability of pericellular growth factors. Indeed, growth factor release was abrogated when cartilage aggrecan was depleted by IL-1 treatment, and in severely damaged human osteoarthritic cartilage. A flux in free matrix sodium upon mechanical compression of cartilage was visualised by 23Na -MRI just below the articular surface. This corresponded to a region of reduced tissue stiffness, measured by scanning acoustic microscopy and second harmonic generation microscopy, and where Smad2/3 was phosphorylated upon cyclic compression. Our results describe a novel intrinsic repair mechanism, controlled by matrix stiffness and mediated by the free sodium concentration, in which heparan sulfate-bound growth factors are released from cartilage upon injurious load. They identify aggrecan as a depot for sequestered sodium, explaining why osteoarthritic tissue loses its ability to repair. Treatments that restore matrix sodium to allow appropriate release of growth factors upon load are predicted to enable intrinsic cartilage repair in OA

Genetic diversity fuels gene discovery for tobacco and alcohol use

Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury(1-4). These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries(5). Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.Peer reviewe

CFD Aided Ship Design and Helicopter Operation

In support of Canadian industrial and defence ship design and offshore helicopter operations, a series of Ship–Helicopter Operational Limits Analysis and Simulation (SHOLAS) projects are being conducted at the National Research Council Canada (NRC) in collaboration with Defence Research and Development Canada (DRDC). This study presents a brief overview of a Canadian in-house ship airwake simulation capability combining in-house high-fidelity wind-tunnel tests, full-scale sea trials, high-order computational fluid dynamics (CFD) tools, and realistic engineering-oriented flight simulators. This paper reports challenges and lessons learned during the course of the study, discusses the current capabilities and limitations of the CFD tools and the infrastructure required, and evaluates the gaps and barriers in industry adoption by focusing on how they could be overcome based on our current practice. After validating the CFD results of an updated version of a simplified frigate shape (SFS2) and the real-world Canadian Patrol Frigate (CPF), which are in reasonable agreement with the available in-house wind-tunnel and sea-trial data, the developed approach was recently applied to the design of an undisclosed Canadian ship. Among other applications, CFD airwake results were used with confidence as input to produce representative airwake features in industrial high-fidelity piloted flight simulators

A single‐institution pediatric and young adult interventional oncology collaborative: Novel therapeutic options for relapsed/refractory solid tumors

Abstract Background Pediatric interventional oncology (PIO) is a growing field intended to provide additional or alternative treatment options for pediatric patients with benign or malignant tumors. Large series of patients treated uniformly and subjected to rigorous endpoints for efficacy are not available. Methods We designed a collaborative initiative to capture data from pediatric patients with benign and malignant tumors who underwent a therapeutic interventional radiology procedure. Modified Response Evaluation Criteria in Solid Tumors (mRECIST) was utilized as a measure of radiologic response and data were collected regarding improvement in pain and functional endpoints. Cumulative incidence of progressive disease was calculated using both the treated site and the patient as the analytic unit. Findings Forty patients, 16 with malignant tumors and 24 with benign tumors, underwent a total of 88 procedures. Cryo‐ and radiofrequency ablation were the most frequently utilized techniques for both cohorts of patients. A complete or partial response, or prolonged disease stability, were achieved in approximately 40% of patients with malignant tumors and 60% of patients with benign tumors. No patients had progressive disease as their best response. Resolution of pain and improved mobility with return‐to‐baseline activity were demonstrated across patients from both cohorts. Only minor complications were experienced. Interpretation Interventional radiology‐guided interventions can serve as an alternative or complementary approach to the treatment of benign and malignant tumors in pediatric patients. Prospective, multi‐institutional trials are required to adequately study utility, treatment endpoints, and durability of response