bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surrogate Modeling for Simultaneous Engine Cycle and Technology Optimization for Next Generation Subsonic Aircraft
Authors: Kestner Brian , Schutte Jeff S. , Tai Jimmy C. M. , Perullo Christopher A. , Mavris Dimitri N. 
Published: July 2013

This paper presents an engine sizing and cycle selection study of ultra high bypass ratio engines applied to a subsonic commercial aircraft in the N+2 (2025) timeframe. NASA has created the Environmentally Responsible Aviation (ERA) project to serve as a technology transition bridge between fundamental research (TRL 1–4) and potential commercial application (TRL 7). Specifically, ERA is focused on subsonic transport technologies that could reach TRL 6 by 2020 and can be integrated into an advanced vehicle concept to simultaneously meet the ERA project metrics for noise, emissions, and fuel burn. An important variable in exploring the technology trade space is the selection of the optimal engine cycle for use on the advanced aircraft. Previous literature demonstrated the cycle optimization using a design of experiments (DOE) to explore the engine cycle design space for a pre-defined technology package. However, since the optimal engine cycle is dependent upon the specific technology package, this process would have to be repeated to ensure optimal performance for each technology package. With more than 80 technologies to be analyzed, the combinatorial space of technology packages is enormous. As a result, executing a DOE to find the optimum engine cycle for each technology package is infeasible. To address this issue, it is proposed to use surrogate models that encompass the engine cycle and technology design space to enable fast and accurate optimization of the engine cycle for any given technology package.
This paper describes the generation and analysis of surrogate models used for technology assessment and cycle optimization of an ultra high bypass geared turbofan engine architecture. The first study in the paper shows that a single surrogate model can be used to accurately simulate both a technology and cycle design space. To demonstrate the proposed surrogate modeling approach, the cycle design space for three different technology packages was analyzed. This study demonstrated that when an optimal cycle is found within the constrained interior of a design space, the surrogate modeling approach is quite accurate. The study also established that the surrogate models can also be used to assess potential cycles at the boundaries or even outside of the region for which they were trained.
Design Feasibility of Annular Target Thrust Reversers
Authors: Gonzalez-Ruiz Enaut , Mahmood Tashfeen , Sethi Vishal , Pilidis Pericles 
Published: July 2013

Concerns for ecological aviation products and the objective of reducing pollutants to meet ACARE (Advisory Council for Aeronautics Research in Europe) targets address, among other initiatives, the necessity of reducing the overall weight of the aircraft. One way of dealing with the problem of aircraft weight is by investigating thrust reversers. Reducing the reverser weight will have favourable effects on fuel consumption and CO2 emissions.
This paper discusses the target type thrust reverser concept. This concept was proposed by NASA and has a potential of reducing the reverser weight on future high bypass ratio turbofan engines. A feasibility study of the annular target thrust reverser in terms of engine performance and reverse thrust achieved was carried out. It comprises 2D CFD analyses of the thrust reverser and the effect of the reverser on the engine performance for different deflector configurations.
The turbofan engine chosen for this study is CUTS_TF (Cranfield University Twin Spool Turbo Fan) which is similar to the GE90-85B and the information available in the public domain [1] [2] is used for the engine performance analysis along with the gas turbine performance software, GasTurb 10 [3]. CFD analyses were performed using the FLUENT software [4] to investigate the thrust reverser flow dynamics at landing at maximum reverse thrust.
Assessing Alternative Fuels for Helicopter Operation
Authors: Alexiou A. , Tsalavoutas A. , Pons B. , Aretakis N. , Roumeliotis I. , Mathioudakis K. 
Published: July 2013

At present, nearly 100% of aviation fuel is derived from petroleum using conventional and well known refining technology. However, the fluctuations of the fuel price and the vulnerability of crude oil sources have increased the interest of aviation industry in alternate energy sources. The motivation of this interest is actually twofold: firstly alternative fuels will help to stabilize price fluctuations by relieving the world wide demand for conventional fuel. Secondly alternative fuels could provide environmental benefits including a substantial reduction of emitted CO2 over the fuel life cycle. Thus, the ideal alternative fuel will fulfil both requirements: relieve the demand for fuels derived from crude oil and significantly reduce CO2 emissions.
In the present paper, the effects of various alternative fuels on the operation of a medium transport/utility helicopter are investigated using performance models of the helicopter and its associated turboshaft engine. These models are developed in an object-oriented simulation environment that allows a direct mechanical connection to be established between them in order to create an integrated model. Considering the case of a typical mission for the specific helicopter/engine combination, a comparative evaluation of conventional and alternative fuels is then carried out and performance results are presented at both engine and helicopter level.
A Parametric Investigation of Integrated Gasification Combined Cycles With Carbon Capture
Authors: Li Xuewei , Wang Ting 
Published: July 2013

IGCC (Integrated Gasification Combined Cycle) technology is being developed to enable electricity to be generated at high efficiency and low emissions. Continuous improvement is essential to make IGCC reliable and cost-effective. As environmental concerns over carbon emissions escalate, development of a practical carbon capture and storage (CCS) technology has become an important issue. Combining IGCC and CCS has become a promising technology to reduce the cost of CCS. This study investigates the pros and cons of different methods used to put together an approximately 250 MW IGCC plant with and without CCS by using the commercial software Thermoflow. Seven different IGCC plants have been designed with various parameters examined, including: oxygen-blown vs. air-blown, with/without integration, with/without CCS, sour vs. sweet water shift for carbon capture, and dry- vs. slurry-fed. This study is based on technologies that are commercially available or close to commercialization. The results show that:
(a) integration between the gas turbine and the air separation unit (ASU) can boost the cycle efficiency about 4.5% (1.6 percentage points);
(b) dry-feeding increases the CO content, the syngas heating value (19%), and the efficiency about 11% (4.7 percentage points);
(c) carbon capture reduces the power output by 2.7% and efficiency by 10% (or 4.5 percentage points) and the slurry-fed system takes a heavier toll on power output and efficiency than the dry-fed system;
(d) air-blown systems do away with the ASU, resulting in syngas with a 50% lower heating value and a small reduction in efficiency, but harvesting savings on reduced capital, operating, and maintenance costs;
(e) for CO2, sweet water shift results in 5.5% (2 percentage points) higher cycle efficiency than sour shift.
Design of an Economical Counter Rotating Fan: Comparison of the Calculated and Measured Steady and Unsteady Results
Authors: Lengyel-Kampmann Timea , Bischoff Andreas , Meyer Robert , Nicke Eberhard 
Published: July 2013

Within the framework of the EU funded Project VITAL, SNECMA (Group Safran), as the work package leader, developed a counter rotating low-speed fan-concept for a high bypass ratio engine. The detailed aerodynamic and mechanical optimization of one blading version (CRTF2.b) was carried out at the German Aerospace Center (DLR), by applying one of the newest design methods featuring a multi-objective automatic optimization method based on an Evolutionary Algorithm [1].
The final design goals were high efficiency, a sufficient stall margin and adequate acoustic performances for the given cycle parameters. The fan stage developed was tested in an anechoic test facility at CIAM in Moscow. The test routine included the measurement of the performance map based on total pressure and total temperature measurements at the inlet and the outlet of the test rig and acoustic measurement as well.
The unsteady flow field of the low speed Contra-Rotating Turbo Fan has been measured with four hot-wire probes at different axial positions.
In the evaluation the measured data are compared with high resolution CFD results. Special emphasis was given to the comparison of the radial distribution of total pressure and total temperature in the bypass channel, the comparison of the measured and the calculated fan maps and to the comparison of the hot-wire measurements with high resolution, unsteady CFD results. The tests and the URANS-results confirmed the design goals.
A Fluid Structure Interaction Approach for Patient Based Abdominal Aortic Aneurysm Rupture Risk Prediction
Authors: Xenos Michalis , Rambhia Suraj , Alemu Yared , Einav Shmuel , Ricotta John J. , Labropoulos Nicos , Tassiopoulos Apostolos , Bluestein Danny 
Published: July 2013

Fluid structure interaction (FSI) simulations of patient-specific fusiform non-ruptured and contained ruptured Abdominal Aortic Aneurysm (AAA) geometries were conducted. The goals were: (1) to test the ability of our FSI methodology to predict the location of rupture, by correlating the high wall stress regions with the rupture location, (2) estimate the state of the pathological condition by calculating the ruptured potential index (RPI) of the AAA and (3) predict the disease progression by comparing healthy and pathological aortas.
The patient specific AAA FSI simulations were carried out with advanced constitutive material models of the various components of AAA, including models that describe wall anisotropy based on collagen fibers orientation within the arterial wall, structural strength of the aorta, intraluminal thrombus (ILT), and embedded calcifications. The anisotropic material model used to describe the wall properties closely correlated with experimental results of AAA specimens.
The results demonstrate that the anisotropic wall simulations showed higher peak wall stresses as compared to isotropic material models, indicating that the latter may underestimate the AAA risk of rupture. The ILT appeared to provide a cushioning effect reducing the stresses, while small calcifications (small-Ca) appeared to weaken the wall and contribute to the rupture risk. FSI simulations with ruptured AAA demonstrated that the location of the maximal wall stresses and RPI overlap the actual rupture region.
Probing Cytoskeletal Mechanics Using Biochemical Inhibitors
Authors: Pryse Kenneth M. , Abney Teresa M. , Genin Guy M. , Elson Elliot L. 
Published: July 2013

Quantifying the mechanics of the cytoskeletons of living cells is important for understanding several physiologic and pathologic cellular functions, such as wound healing and cellular migration in cancer. Our laboratory develops three-dimensional tissue constructs for assaying cytoskeletal mechanics in controlled conditions. These tissue constructs consist of defined components such as chick embryo fibroblasts and reconstituted rat tail collagen; fibroblasts remodel the collagen extracellular matrix (ECM) and develop a structural environment representative of that which would exist in a natural tissue.
Our protocol for quantifying the microscale mechanics of the proteins that comprise the cytoskeleton involves mechanical testing of a tissue construct first in a bath that contains nutrition medium to support the active physiologic functioning of the cells, and next in the presence of inhibitors that selectively eliminate specific cytoskeletal structures. By solving an inverse homogenization problem, the mechanical functioning of these proteins at the cellular level can be estimated. Here, we present a combination of mechanical testing and imaging results to quantify the effects of specific inhibitors on cytoskeletal and extracellular matrix form and function.
The Dominant Mechanical Interaction Between the Brain and Skull In Vivo: Is Sliding Arrested at Key Points of Brain-Skull Tethering?
Authors: Abney Teresa M. , Feng Y. Aaron , Pless Robert , Okamoto Ruth J. , Genin Guy M. , Bayly Philip V. 
Published: July 2013

The relationship between skull acceleration and brain injury is not well understood, in large part because of the challenge of visualizing the brain’s mechanical response in vivo. This difficulty also complicates the validation of computational mechanics predictions.
Our dynamic magnetic resonance (MR) imaging suggests an important role for the attachments between brain and skull. Here, we present an MRI-based method for identifying the dominant modes of brain displacement relative to the skull during angular acceleration of the head, and apply it to study brain/skull interactions in live volunteers. The approach was to estimate dynamic intracranial displacement fields from a sequence of tagged MR images of the brain and skull, then identify dominant displacement modes using principal component (PC) analysis. After verifying the method through analysis of a simulated 2-D vibrating plate and MR images of a cylindrical gel phantom, the method was applied to show that the dominant mode of brain/skull interaction is one of sliding arrested by brain/skull meninges in a few specific regions.
Testing of the Prototype Low-Durometer Hybrid III Neck for Improved Biofidelity
Authors: Paver Jacqueline G. , Caplinger Justin , Mattos Garrett , Friedman Donald 
Published: July 2013

This study is part of an ongoing research project aimed at mitigating catastrophic human neck injuries, predominantly due to neck bending, in rollover crashes. Presently, the Hybrid III dummy is considered to be the best available human surrogate for dynamic rollover tests. However, there are known biofidelity and instrumentation limitations associated with its use to predict catastrophic neck injuries in real-world rollover crashes.
A previous study investigated the use of the non-biofidelic Hybrid III dummy in a dynamic rollover test to accurately predict the predominant human neck bending injury sustained in real-world rollover crashes. An empirical relationship between upper and lower Hybrid III neck loading was derived. The effects of neck preflexion angle, roof impact speed, roof crush, onset-to-peak neck axial forces and moments, and impact duration on neck bending injury were identified. Peak neck injury measures were rejected.
For this study, the 67-durometer Hybrid III production neck was fabricated with more compliant 35-durometer butyl rubber in order improve the dummy biofidelity in rollover tests. The tests in the previous study were repeated. Correlations were established between the prototype and production necks. Parametric studies of the prototype neck revealed similar trends as observed with the Hybrid III production neck.
O-010 The Barrow Neurological Institute Experience with the Pipeline Embolisation Device: Results in the First 100 Patients Treated after FDA Approval
Authors: Albuquerque F , Ducruet A , Crowley W , McDougall C 
Published: July 2013

Aims and ObjectivesThe Pipeline Embolisation Device (PED) was recently approved in the United States (US) for the treatment of wide-necked anterior circulation aneurysms. Studies in both the US and Europe have confirmed its efficacy as well as an acceptable complication rate associated with its use. In this setting, we sought to analyse our results prospectively in the first 100 patients treated at our institution since FDA approval of the device in May of 2011.Materials and MethodsWe analysed all patients treated with the PED, specifically assessing the following factors: patient demographics, number of devices used, aneurysm location, clinical/angiographic follow-up, rate of obliteration, number of residual aneurysms, and complications.Results and Discussion100 patients with 115 aneurysms were treated with the PED. Of these, there were 19 men and 81 women ranging in age from 23 to 83 years (mean = 59.2 years). A total of 185 PEDs were used with an average of 1.85 per patient. Aneurysm locations were myriad with the peri-ophthalmic and cavernous segments comprising the largest proportion (35 and 33 aneurysms respectively). Fourteen posterior circulation aneurysms were treated in this cohort. Radiographic follow-up was obtained in 68 patients at an average of 6.6 months after treatment. Of these, 45 patients demonstrated complete obliteration of their aneurysms and 12 patients near-complete (< 90%). The rate of complete and near-complete obliteration was 83.8%. A total of 20 complications occurred with 3 of these being permanent and 17 transient. The 3 permanent complications included 2 deaths and 1 stroke. Patient compliance with and/or tolerance of anti-platelet therapy was a major factor accounting for complications. The overall rate of permanent complications was 3%.ConclusionsThe PED is a safe and effective means of treating complex cerebral aneurysms. Nonetheless, a number of technical factors and patient compliance issues complicate its use.DisclosuresF. Albuquerque: None. A. Ducruet: None. W. Crowley: None. C. McDougall: None.
E-042 Case Based Review of the Pathophysiology of Internal Carotid Artery Pseudoaneurysm Coil Migration
Authors: Morgan R , Best S , Connor C , Madarang J , Johnson P 
Published: July 2013

Learning ObjectivesReview the pathophysiology and risk factors of internal carotid artery (ICA) pseudoaneurysm formation.Evaluate imaging of coil migration following endovascular treatment of internal carotid artery pseudoaneurysm.Discuss treatment options of coil migration.BackgroundPseudoaneurysm results from disruption of one or more layers of the arterial wall, which results in blood dissecting into the surrounding tissues. The formation of ICA pseudoaneurysm is a known complication related to radiation therapy and arterial injury during surgery. Endovascular coil embolisation has been proven an effective treatment for ICA pseudoaneurysm, however one of the rare complications is coil migration.Clinical Findings/Procedure DetailsTwo patients with history of iatrogenic ICA injury during tumour resection subsequently developed pseudoaneurysms. Both were initially treated with endovascular coil embolisation and both went on to suffer migration and prolapse of the coil into the pharynx. In both cases the coil mass demonstrated migration with erosion through the pseudoaneurysm wall. The first patient underwent coil embolisation 20 years prior to presenting with globus sensation and epistaxis. The second patient, who had previously been treated with radiation, developed transmucosal coil migration 1 month after embolisation. In both cases the complications associated with coil migration were fatal.Conclusion and/or Teaching PointsWhen treating ICA pseudoaneurysm with coil embolisation there are multiple factors which can increase the risk of coil migration. While it is rare coil migration is a known complication of endovascular embolisation which can occur months to decades after the initial procedure.DisclosuresR. Morgan: None. S. Best: None. C. Connor: None. J. Madarang: None. P. Johnson: None.
E-044 The Penumbra 5MAX, 4MAX and 3MAX Reperfusion Catheters in Treatment of Acute Ischaemic Stroke: Initial Clinical Experience
Authors: Farkas J , Arcot K , Walzman D , Kumar R , Delbrune J , Papamitsakis N , Margulis Y , Dash S , Levin K , Azhar S 
Published: July 2013

Introduction/PurposeThe new material composition and larger, tapered lumen in the distal end of the novel Penumbra MAX System reperfusion catheters are designed to enhance aspiration efficiency with improved trackability. Reported herein are results from a retrospective multicentre study with the Penumbra System 5MAX, 4MAX and 3MAX reperfusion catheters in the treatment of acute ischaemic stroke secondary to large vessel occlusion.Materials and MethodsA retrospective case-review of 19 consecutive acute ischaemic stroke cases treated with the Penumbra System either as a standalone device or in combination: 5MAX (n=8), 4MAX (n=6) and 3MAX (n=8), from July 2012 through December 2012 was undertaken. Clinical experience at 3 institutions was collected and reported in the first six months after device release. Occlusions were located in the MCA M1and M2 (n=11), ICA and ICA/MCA (n=6), and vertebrobasilar arteries (n=2).ResultsEighteen of 19 cases (94.7%) were successfully recanalised to TICI 2 and 3 using the Penumbra MAX System. Complete revascularisation to TICI 3 was achieved in 16 of 19 (84%). The mean patient age was 70.3 ± 13.9 years; the median NIHSS score at presentation was 19 (15 to 29). All patients presented with TICI scores of 0 or 1. At discharge, the median NIHSS score was 14 (1 to 29). One death due to cardiac arrest occurred at 15 days post-procedure. In one patient, stroke in a new territory was observed and treated with IA rtPA. One ICH was found in a previously unaffected region, possibly secondary to IV rtPA therapy.ConclusionEarly multicentre experience indicates that the 5MAX, 4MAX and 3MAX reperfusion catheters have enhanced aspiration efficiency and trackability. Follow-up studies will be required to verify these findings.DisclosuresJ. Farkas: None. K. Arcot: None. D. Walzman: None. R. Kumar: None. J. Delbrune: None. N. Papamitsakis: None. Y. Margulis: None. S. Dash: None. K. Levin: None. S. Azhar: None.