Waste Heat Recovery in a Compression Ignition Engine for Marine Application Using a Rankine Cycle Operating with an Innovative Organic Working Fluid

The exhaust heat of energy conversion systems can be usefully recovered by Organic Rankine Cycles (ORC) instead of wasting it into the environment, with benefits in terms of system efficiency and environmental impact. Rankine cycle technology, consolidated in stationary power plants, has not yet spread out into transport applications due to the layout limitations and to the necessity of containing the size and weight of the ORC system. The authors investigated an ORC system bottoming a compression ignition engine for marine application. The exhaust mass flow rate and temperature, measured at different engine loads, have been used as inputs for modeling the ORC plant in a Simulink environment. An energy and exergy analysis of the ORC was performed, as well as the evaluation of the ORC power at different engine loads. Two different working fluids were considered: R1233zd(e), an innovative fluid belonging to the class of hydrofluoroolefin, still in development but interesting due to its low flammability, health hazard, and environmental impact, and R601, a hydrocarbon showing a benchmark thermodynamic performance but highly flammable, considered as a reference for comparison. Three plant configurations were investigated: single-pressure, dual-pressure, and reheating. The results demonstrated that the dual-pressure configuration achieves the highest exploitation of exhaust heat. R1233zd(e) produced an additional mechanical power of 8.0% with respect to the engine power output, while, for R601, the relative contribution of the ORC power was 8.7%

Abstract 1122‐000207: Mechanical Thrombectomy of the Fetal Posterior Cerebral Artery

Introduction: Fetal posterior cerebral artery (FPCA) occlusion is a rare but potentially disabling cause of stroke. While endovascular treatment is established for acute large vessel occlusion (LVO) stroke, FPCA occlusions were excluded from acute ischemic stroke trials. We aim to report the feasibility, safety and outcome of mechanical thrombectomy (MT) in acute FPCA occlusions. Methods: We performed a multi‐center retrospective review of consecutive patients who underwent MT of acute FPCA occlusion. Primary FPCA occlusion was defined as an occlusion that was identified on the pre‐procedure CT angiogram or baseline angiogram whereas a secondary FPCA occlusion was defined as an occlusion that occurred secondary to embolization to a new territory after recanalization of a different LVO. Demographics, clinical presentation, imaging findings, endovascular treatment and outcome were reviewed. Results: There were twenty‐five patients with acute FPCA occlusion who underwent MT, distributed across 14 centers. Median NIHSS on presentation was 16. There were 76% (19/25) of patients who presented with primary FPCA occlusion and 24% (6/25) of patients who had a secondary FPCA occlusion. The configuration of the FPCA was full in 64% patients and partial or “fetal‐type” in 36% of patients. FPCA occlusion was missed on initial CTA in 21% of patients with primary FPCA occlusion (4/19). The site of occlusion was posterior communicating artery in 52%, P2 segment in 40% and P3 in 8% of patients. TICI 2b/3 reperfusion was achieved in 96% of FPCA patients. There were no intra‐procedural complications. At 90 days, 48% (12/25) were functionally independent as defined by mRS≤2. Conclusions: Endovascular treatment of acute FPCA occlusion is safe and technically feasible. A high index of suspicion is important to detect occlusion of the fetal posterior cerebral artery in patients presenting with anterior circulation stroke syndrome and patent anterior circulation

Mechanical Thrombectomy of the Fetal Posterior Cerebral Artery

Background Fetal posterior cerebral artery (FPCA) occlusion is a rare but potentially disabling cause of stroke. While endovascular treatment is established for acute large vessel occlusion stroke, FPCA occlusions were excluded from acute ischemic stroke trials. We aim to report the feasibility, safety, and outcome of mechanical thrombectomy in acute FPCA occlusions. Methods We performed a multicenter retrospective review of consecutive patients who underwent mechanical thrombectomy of acute FPCA occlusion. Primary FPCA occlusion was defined as an occlusion that was identified on the pre‐procedure computed tomography angiography or baseline angiogram whereas a secondary FPCA occlusion was defined as an occlusion that occurred secondary to embolization to a new territory after recanalization of a different large vessel occlusion. Demographics, clinical presentation, imaging findings, endovascular treatment, and outcome were reviewed. Results There were 25 patients with acute FPCA occlusion who underwent mechanical thrombectomy, distributed across 14 centers. Median National Institutes of Health Stroke Scale on presentation was 16. There were 76% (19/25) of patients who presented with primary FPCA occlusion and 24% (6/25) of patients who had a secondary FPCA occlusion. The configuration of the FPCA was full in 64% patients and partial or “fetal‐type” in 36% of patients. FPCA occlusion was missed on initial computed tomography angiography in 21% of patients with primary FPCA occlusion (4/19). The site of occlusion was posterior communicating artery in 52%, P2 segment in 40% and P3 in 8% of patients. Thrombolysis in cerebral infarction 2b/3 reperfusion was achieved in 96% of FPCA patients. There were no intraprocedural complications. At 90 days, 48% (12/25) were functionally independent as defined by modified Rankin scale≤2. Conclusions Endovascular treatment of acute FPCA occlusion is safe and technically feasible. A high index of suspicion is important to detect occlusion of the FPCA in patients presenting with anterior circulation stroke syndrome and patent anterior circulation. Novelty and significance This is the first multicenter study showing that thrombectomy of FPCA occlusion is feasible and safe