Flight Test Methodology for NASA Advanced Inlet Liner on 737MAX-7 Test Bed (Quiet Technology Demonstrator 3)

This paper describes the acoustic flight test results of an advanced nacelle inlet acoustic liner concept designed by NASA Langley, in a campaign called Quiet Technology Demonstrator 3 (QTD3). NASA has been developing multiple acoustic liner concepts to benefit acoustics with multiple-degrees of freedom (MDOF) honeycomb cavities, and lower the excrescence drag. Acoustic and drag performance were assessed at a lab-scale, flow duct level in 2016. Limitations of the lab-scale rig left open-ended questions regarding the in-flight acoustic performance. This led to a joint project to acquire acoustic flyover data with this new liner technology built into full scale inlet hardware containing the NASA MDOF Low Drag Liner. Boeing saw an opportunity to collect the acoustic flyover data on the 737 MAX-7 between certification tests at no impact to the overall program schedule, and successfully executed within the allotted time. The flight test methodology and the test configurations are detailed and the acoustic analysis is summarized in this paper. After the tone and broadband deltas associated with the inlet hardware were separated and evaluated, the result was a significant decrease in cumulative EPNL (Effective Perceived Noise Level)

Acoustic Phased Array Quantification of Quiet Technology Demonstrator 3 Advanced Inlet Liner Noise Component

Acoustic phased array flyover noise measurements were acquired as part of the Boeing 737 MAX-7 NASA Advanced Inlet Liner segment of the Quiet Technology Demonstrator 3 (QTD3) flight test program. This paper reports on the processes used for separating and quantifying the engine inlet, exhaust and airframe noise source components and provides sample phased array-based comparisons of the component noise source levels associated with the inlet liner treatment configurations. Full scale flyover noise testing of NASA advanced inlet liners was conducted as part of the Quiet Technology Demonstrator 3 flight test program in July and August of 2018. Details on the inlet designs and testing are provided in the companion paper of Reference 1. The present paper provides supplemental details relating to the acoustic phased array portion of the analyses provided in Ref. 1. In brief, the test article was a Boeing 737MAX-7 aircraft with a modified right hand (starboard side) engine inlet, which consisted of either a production inlet liner, a NASA designed inlet liner or a simulated hard wall configuration (accomplished by applying speed tape over the inlet acoustic treatment areas). In all three configurations, the engine forward fan case acoustic panel was replaced with a unperforated (hardwall) panel. No other modifications to any other acoustic treatment areas were made. The left hand (port side) engine was a production engine and was flown at idle thrust for all measurements in order to isolate the effects of the inlet liners to the right hand engine. As described in Ref. 1, the NASA inlet treatment consists of laterally cut slots (cut perpendicular to the flow direction) which are designed to reduce excrescence drag while maintaining or exceeding the liner acoustic noise reduction capabilities. The NASA inlet liner consists of a Multi-Degree of Freedom (MDOF) design with two breathable septum layers inserted into each honeycomb cell [1]. The aircraft noise measurements were acquired for both takeoff (flaps 1 setting, gear up) and approach (flaps 30 gear up and gear down) configurations. The inlet and flight test configurations are summarized in Table 1. Table 1: Inlet Treatment and Flight Configurations Inlet Forward Fan Case Aircraft Production Hardwall Flaps 1, gear up; flaps 30 gear up; flaps 30 gear down NASA Hardwall Flaps 1, gear up; flaps 30 gear up; flaps 30 gear down Hardwall Hardwall Flaps 1, gear up; flaps 30 gear up; flaps 30 gear down III.Test Description and Hardware The flight testing was conducted at the Grant County airport in Moses Lake, WA, between 27 July and 6 August 2018. The noise measurement instrumentation included 8 flush dish microphones arranged in a noise certification configuration as well as an 840 microphone phased array. The flush dish microphones were used to quantify the levels and differences in levels between the various inlet treatments. The phased array was used to separate and quantify the narrowband (tonal) and broadband noise component levels from the engine inlet/exhaust and from the airframe. Phased array extraction of the broadband component was critical to this study because it allowed for the separation of the inlet component from the total airplane level noise even when it was significantly below the total level. Figure 1 provides an overview of the phased array microphone layout as well as a detailed image of an individual phased array microphone mounted in a plate holder (the microphone sensor is the dot in the center of the plate). The ground plane ensemble array microphones (referred to as ensemble array in this paper) were mounted in plates with flower petal edges designed to minimize edge scattering effects. Fig. 1 Flyover test microphone layout. The phased array configuration was the result of a progressive development of concepts originally implemented in Ref. 2 and refined over the following years, consisting namely of multiple multi-arm logarithmic spiral subarrays designed to cover overlapping frequency ranges and optimized for various aircraft emission angles. For the present case, the signals from all 840 microphones were acquired on a single system. The 840 microphones were parsed into 11 primary subarray sets spanning from smallest to largest aperture size and labeled accordingly as a, b, , k, where a corresponds to the smallest fielded subarray and k corresponds to the largest aperture subarray. The apertures ranged from approximately 10 ft to 427 ft in size (in the flight direction) with the subarrays consisting of between 215 and 312 microphones. Figure 2 shows three such subarrays, k, h and a. As done in Ref. 2, microphones were shared between subarrays in order to reduce total channel count. Fig. 2 Sample subarray sizes (20 from overhead refer to Figure 3a discussion). In addition to the above, each of the 11 primary subarray sets consisted of four subarrays optimized to provide near equivalent array spatial resolution in both the flight and lateral directions within 30 degrees of overhead (i.e., airplane directly above the center of the array), namely, at angles of 0, 10, 20 and 30 degrees relative to overhead where angle is defined as shown in Figure 3a. This allowed for optimized aircraft noise measurements from 60 to 120 degree emission angle.6 An example of this pletharray design is shown in Figure 3b for the k subarray. When the aircraft is at overhead, the microphones indicated by the blue markers are used for beamforming. When the aircraft is at angles 10 degrees from overhead, both the blue and red colored microphones are used, and so on for the 20 and 30 degree aircraft locations. See Ref. 3 for extensive details on pletharray design for aeroacoustic phased array testing. 6 In the discussions that follow, emission angle values are used. These are the angles at the time sound is emitted relative to the engine axis and are calculated based on flight path angle, body aircraft body angle with respect to the relative wind direction, and engine axis angle relative to aircraft body angle

Analysis of Minerals Using Specimen Isolated Secondary Ion Mass Spectrometry

Considerably improved suppression of molecular ions in secondary ion mass spectrometry (SIMS) spectra of nonconductor minerals has been obtained using a CAMECA IMS-3f ion microscope with unconventional operating conditions [so-called specimen isolated (SI) conditions]. In a zircon spectrum close to forty elements are positively identified and molecular ions such as oxides and hydrides have very low intensities. Thus, with a 28Si+ intensity of 106 cps, the Si+/Si0+ ratio is 105, and the 30SiH+ intensity is low enough to enable quantitative analysis using 31P+ down to 0.01 wt % P2O5 in a silicate glass matrix. The SI conditions enable us to follow major, minor and trace element concentrations across a complex alteration zone such as a sphene/hornblende contact. Isotope ratios show reasonable agreement with natural isotopic abundances, but relatively large kinetic energy induced isotopic fractionation is observed due to our analysis of high kinetic energy secondary ions. For zircon, and sphene samples, the isotope fractionation plotted against the mass ratios of the isotopes shows a linear dependence

Flight Test Results for Uniquely Tailored Propulsion-Airframe Aeroacoustic Chevrons: Shockcell Noise

Azimuthally varying chevrons (AVC) which have been uniquely tailored to account for the asymmetric propulsion-airframe aeroacoustic interactions have recently shown significant reductions in jet-related community noise at low-speed take-off conditions in scale model tests of coaxial nozzles with high bypass ratio. There were indications that such AVCs may also provide shockcell noise reductions at high cruise speeds. This paper describes the flight test results when one such AVC concept, namely, the T-fan chevrons with enhanced mixing near the pylon, was tested at full-scale on a modern large twin-jet aircraft (777-300ER) with focus on shockcell noise at mid-cruise conditions. Shockcell noise is part of the interior cabin noise at cruise conditions and its reduction is useful from the viewpoint of passenger comfort. Noise reduction at the source, in the exhaust jet, especially, at low frequencies, is beneficial from the perspective of reduced fuselage sidewall acoustic lining. Results are shown in terms of unsteady pressure spectra both on the exterior surface of the fuselage at several axial stations and also microphone arrays placed inside the fuselage aft of the engine. The benefits of T-fan chevrons, with and without conventional chevrons on the core nozzle, are shown for several engine operating conditions at cruise involving supersonic fan stream and subsonic or supersonic core stream. The T-fan AVC alone provides up to 5 dB low-frequency noise reduction on the fuselage exterior skin and up to 2 dB reduction inside the cabin. Addition of core chevrons appears to increase the higher frequency noise. This flight test result with the previous model test observation that the T-fan AVCs have hardly any cruise thrust coefficient loss (< 0.05%) make them viable candidates for reducing interior cabin noise in high bypass ratio engines

Design of passive piezoelectric damping for space structures

Passive damping of structural dynamics using piezoceramic electromechanical energy conversion and passive electrical networks is a relatively recent concept with little implementation experience base. This report describes an implementation case study, starting from conceptual design and technique selection, through detailed component design and testing to simulation on the structure to be damped. About 0.5kg. of piezoelectric material was employed to damp the ASTREX testbed, a 500kg structure. Emphasis was placed upon designing the damping to enable high bandwidth robust feedback control. Resistive piezoelectric shunting provided the necessary broadband damping. The piezoelectric element was incorporated into a mechanically-tuned vibration absorber in order to concentrate damping into the 30 to 40 Hz frequency modes at the rolloff region of the proposed compensator. A prototype of a steel flex-tensional motion amplification device was built and tested. The effective stiffness and damping of the flex-tensional device was experimentally verified. When six of these effective springs are placed in an orthogonal configuration, strain energy is absorbed from all six degrees of freedom of a 90kg. mass. A NASTRAN finite element model of the testbed was modified to include the six-spring damping system. An analytical model was developed for the spring in order to see how the flex-tensional device and piezoelectric dimensions effect the critical stress and strain energy distribution throughout the component. Simulation of the testbed demonstrated the damping levels achievable in the completed system

How the story unfolds: exploring ways faculty develop open-ended and closed-ended case designs. Adv Physiol Educ 32: 279–285

Nesbitt LM, Cliff WH. How the story unfolds: exploring ways faculty develop open-ended and closed-ended case designs. Adv Physiol Educ 32: 279-285, 2008; doi:10.1152/advan.90158.2008.-Open-ended or closed-ended case study design schemes offer different educational advantages. Anatomy and physiology faculty members who participated in a conference workshop were given an identical case about blood doping and asked to build either an open-ended study or a closed-ended study. The workshop participants created a rich array of case questions. Participant-written learning objectives and case questions were compared, and the questions were examined to determine whether they satisfied criteria for open or closed endedness. Many of the participant-written learning objectives were not well matched with the case questions, and participants had differing success writing suitable case questions. Workshop participants were more successful in creating closed-ended questions than open-ended ones. Eighty-eight percent of the questions produced by participants assigned to write closed-ended questions were considered closed ended, whereas only 43% of the questions produced by participants assigned to write open-ended questions were deemed open ended. Our findings indicate that, despite the fact that instructors of anatomy and physiology recognize the value of open-ended questions, they have greater difficulty in creating them. We conclude that faculty should pay careful attention to learning outcomes as they craft open-ended case questions if they wish to ensure that students are prompted to use and improve their higher-order thinking skills. case-based learning; learning objectives; convergent questions; divergent questions; questioning CASES are stories with an educational message (7) and have garnered widespread interest among instructors in the biomedical sciences (11). How these stories unfold depends on the ingenuity of the case designer. The best case studies are written to invite students to explore a multitude of intellectual pathways with learning objectives serving as trail markers for the educational journey ahead (2). In the same way that a master storyteller often fashions a tale to have alternate endings, the case author is at liberty to develop case studies in differing directions-narrowing or widening, closing or opening the scope of the study-as pedagogical needs arise. Previously, we have described some of the essential features that distinguish open-ended from closed-ended case study design elements (2). We noted that open-ended case designs permit multiple solutions [i.e., are divergent (3, 13)] since the knowledge needed to solve the case study may be in flux, the necessary information may not be known or available, or certainty cannot be obtained. Alternately, closed-ended designs usually have a single solution [i.e., are convergent (3, 13)] since the knowledge required is well defined and the information needed is readily accessible. We concluded that, depending on the goal for student learning, either type of case approach can yield outcomes that are beneficial for student understanding. Underlying these contentions was the assumption that, starting from the same scenario, case studies can be profitably unfolded along either open-or closed-ended avenues. While our suggestions generate a helpful framework for choosing between open-and closed-ended design schemes, we realized that our thesis would gain greater definition if we demonstrated the construction of actual case studies illustrating the salient features of both types of architectures. Even though we could have produced such case studies on our own, we hypothesized that by helping other faculty members understand the features of open-and closed-ended case studies, we could enable them to generate useful exemplars. So, we asked a group of instructors of anatomy and physiology to fashion open-or closed-ended components of a single case study as they participated in a workshop that highlighted the features and benefits of both open and closed case design. By doing so, we saw the potential to obtain a much richer tapestry of case elements than we could have invented ourselves, and we recognized that we might also be able to uncover some of the adequacies and inadequacies of faculty members as they approach the design process. Thus, we saw the value in carefully examining and reporting the efforts of workshop participants to develop open-and closed-ended features of a single case. Here, we describe on our efforts to 1) solicit from workshop participants their thoughts on the advantages of closed-and open-ended designs and 2) determine how participants would build a case study following either an open-ended approach or a closed-ended approach to case design when starting from an identical case scenario. We chose a short story about blood doping by an Olympic athlete that offered multiple avenues of inquiry, presented a dilemma to be addressed, and was replete with the social, behavioral, and ethical implications of physiology that Penny Hansen has described as a component of the discipline&apos;s recondite curriculum (6). Given this scenario, participants were asked to begin developing a case study by creating the design elements, i.e., learning objectives and corresponding case questions, which would guide and stimulate student learning. By examining the products of the participant&apos;s work, we intended to examine and analyze the design schemes they used as they created open-or closed-ended approaches to case studies. METHODS Two workshops, entitled &quot;Open-Ended and Closed-Ended Approaches to the Design of Case Studies,&quot; were offered as part of the program of the 2002 national meeting of the Human Anatomy and Physiology Society. The workshop participants consisted of ϳ50 anatomy and physiology educators who were interested in the use o

Scaling and Formulary cross sections for ion-atom impact ionization

The values of ion-atom ionization cross sections are frequently needed for many applications that utilize the propagation of fast ions through matter. When experimental data and theoretical calculations are not available, approximate formulas are frequently used. This paper briefly summarizes the most important theoretical results and approaches to cross section calculations in order to place the discussion in historical perspective and offer a concise introduction to the topic. Based on experimental data and theoretical predictions, a new fit for ionization cross sections is proposed. The range of validity and accuracy of several frequently used approximations (classical trajectory, the Born approximation, and so forth) are discussed using, as examples, the ionization cross sections of hydrogen and helium atoms by various fully stripped ions.Comment: 46 pages, 8 figure

Twenty-five coregulated transcripts define a sterigmatocystin gene cluster in Aspergillus nidulans.

Sterigmatocystin (ST) and the aflatoxins (AFs), related fungal secondary metabolites, are among the most toxic, mutagenic, and carcinogenic natural products known. The ST biosynthetic pathway in Aspergillus nidulans is estimated to involve at least 15 enzymatic activities, while certain Aspergillus parasiticus, Aspergillus flavus, and Aspergillus nomius strains contain additional activities that convert ST to AF. We have characterized a 60-kb region in the A. nidulans genome and find it contains many, if not all, of the genes needed for ST biosynthesis. This region includes verA, a structural gene previously shown to be required for ST biosynthesis, and 24 additional closely spaced transcripts ranging in size from 0.6 to 7.2 kb that are coordinately induced only under ST-producing conditions. Each end of this gene cluster is demarcated by transcripts that are expressed under both ST-inducing and non-ST-inducing conditions. Deduced polypeptide sequences of regions within this cluster had a high percentage of identity with enzymes that have activities predicted for ST/AF biosynthesis, including a polyketide synthase, a fatty acid synthase (alpha and beta subunits), five monooxygenases, four dehydrogenases, an esterase, an 0-methyltransferase, a reductase, an oxidase, and a zinc cluster DNA binding protein. A revised system for naming the genes of the ST pathway is presented

Evaluation of simulation training in cardiothoracic surgery: The Senior Tour perspective

OBJECTIVE: The study objective was to introduce senior surgeons, referred to as members of the "Senior Tour," to simulation-based learning and evaluate ongoing simulation efforts in cardiothoracic surgery. METHODS: Thirteen senior cardiothoracic surgeons participated in a 2½-day Senior Tour Meeting. Of 12 simulators, each participant focused on 6 cardiac (small vessel anastomosis, aortic cannulation, cardiopulmonary bypass, aortic valve replacement, mitral valve repair, and aortic root replacement) or 6 thoracic surgical simulators (hilar dissection, esophageal anastomosis, rigid bronchoscopy, video-assisted thoracoscopic surgery lobectomy, tracheal resection, and sleeve resection). The participants provided critical feedback regarding the realism and utility of the simulators, which served as the basis for a composite assessment of the simulators. RESULTS: All participants acknowledged that simulation may not provide a wholly immersive experience. For small vessel anastomosis, the portable chest model is less realistic compared with the porcine model, but is valuable in teaching anastomosis mechanics. The aortic cannulation model allows multiple cannulations and can serve as a thoracic aortic surgery model. The cardiopulmonary bypass simulator provides crisis management experience. The porcine aortic valve replacement, mitral valve annuloplasty, and aortic root models are realistic and permit standardized training. The hilar dissection model is subject to variability of porcine anatomy and fragility of the vascular structures. The realistic esophageal anastomosis simulator presents various approaches to esophageal anastomosis. The exercise associated with the rigid bronchoscopy model is brief, and adding additional procedures should be considered. The tracheal resection, sleeve resection, and video-assisted thoracoscopic surgery lobectomy models are highly realistic and simulate advanced maneuvers. CONCLUSIONS: By providing the necessary tools, such as task trainers and assessment instruments, the Senior Tour may be one means to enhance simulation-based learning in cardiothoracic surgery. The Senior Tour members can provide regular programmatic evaluation and critical analyses to ensure that proposed simulators are of educational value