Auralization of a Supersonic Business Jet Using Advanced Takeoff Procedures

Recent NASA studies of a supersonic business jet airplane indicated that advanced takeoff procedures could be used to reduce noise at the lateral sideline location to a level at which Chapter 4 noise certification requirements could be met. The studies were conducted with the NASA Aircraft Noise Prediction Program, using an analytical model of the airframe and its engines. The advanced procedure consists of a higher-speed climbout and a programmed thrust lapse in which the engine thrust is automatically and gradually reduced immediately after the runway obstacle is cleared. In this paper, the authors utilize the results of the most recent study as the basis of an auralization of the predicted noise. Modifications to the NASA Auralization Framework necessary for that process are described. The auralizations are used to demonstrate differences between standard and advanced takeoff pro ond those that may be observed through comparison of integrated noise metrics

The NASA Auralization Framework and Plugin Architecture

NASA has a long history of investigating human response to aircraft flyover noise and in recent years has developed a capability to fully auralize the noise of aircraft during their design. This capability is particularly useful for unconventional designs with noise signatures significantly different from the current fleet. To that end, a flexible software architecture has been developed to facilitate rapid integration of new simulation techniques for noise source synthesis and propagation, and to foster collaboration amongst researchers through a common releasable code base. The NASA Auralization Framework (NAF) is a skeletal framework written in C++ with basic functionalities and a plugin architecture that allows users to mix and match NAF capabilities with their own methods through the development and use of dynamically linked libraries. This paper presents the NAF software architecture and discusses several advanced auralization techniques that have been implemented as plugins to the framework

Development of a human knee joint finite element model to investigate cartilage stress during walking in obese and normal weight adults

Osteoarthritis (OA) is a degenerative condition characterized by the breakdown and loss of joint articular cartilage. While the cause of OA is not precisely known, obesity is a known risk factor [1]. Particular effort has gone towards understanding the relationship between obesity and knee OA because obesity is more strongly linked to OA at the knee than at any other lower extremity joint [2]. Although the relationship between obesity and knee OA is well established, the mechanism of pathogenesis is less understood. Excess body weight generates greater joint contact forces at the knee. However, obese individuals alter their gait, resulting in increased joint contact forces that are not proportional to body mass [3]. In this study, a partially validated knee joint finite element (FE) model was developed to predict cartilage loading during walking across individuals of varying adiposity. The model was used with kinematic and kinetic gait data to address the following hypotheses: 1) increased loading due to obesity will produce greater cartilage stress compared to the normal weight control; and 2) altered gait kinematics of obese individuals will alter the distribution of stress on the surface of the tibial cartilage

Radiation Test Results for a MEMS Microshutter Operating at 60 K

The James Webb Space Telescope (JWST), the successor to the Hubble Space Telescope, is due to be launched in 2013 with the goal of searching the very distant Universe for stars that formed shortly after the Big Bang. Because this occurred so far back in time, the available light is strongly red-shifted, requiring the use of detectors sensitive to the infrared portion of the electromagnetic spectrum. HgCdTe infrared focal plane arrays, cooled to below 30 K to minimize noise, will be used to detect the faint signals. One of the instruments on JWST is the Near Infrared Spectrometer (NIRSPEC) designed to measure the infrared spectra of up to 100 separate galaxies simultaneously. A key component in NIRSPEC is a Micro-Electromechanical System (MEMS), a two-dimensional micro-shutter array (MSA) developed by NASA/GSFC. The MSA is inserted in front of the detector to allow only the light from the galaxies of interest to reach the detector and to block the light from all other sources. The MSA will have to operate at 30 K to minimize the amount of thermal radiation emitted by the optical components from reaching the detector array. It will also have to operate in the space radiation environment that is dominated by the MSA will be exposed to a large total ionizing dose of approximately 200 krad(Si). Following exposure to ionizing radiation, a variety of MEMS have exhibited performance degradation. MEMS contain moving parts that are either controlled or sensed by changes in electric fields. Radiation degradation can be expected for those devices where there is an electric field applied across an insulating layer that is part of the sensing or controlling structure. Ionizing radiation will liberate charge (electrons and holes) in the insulating layers, some of which may be trapped within the insulating layer. Trapped charge will partially cancel the externally applied electric field and lead to changes in the operation of the MEMS. This appears to be a general principle for MEMS. Knowledge of the above principle has raised the concern at NASA that the MSA might also exhibit degraded performance because, i) each shutter flap is a multilayer structure consisting of metallic and insulating layers and ii) the movement of the shutter flaps is partially controlled by the application of an electric field between the shutter flap and the substrate (vertical support grid). The whole mission would be compromised if radiation exposure were to prevent the shutters from opening and closing properly. energetic ionizing particles. Because it is located A unique feature of the MSA is that, as outside the spacecraft and has very little shielding, previously mentioned, it will have to operate at temperatures near 30 K. To date, there are no published reports on how very low temperatures (- 30K) affect the response of MEMS devices to total ionizing dose. Experiments on SiO2 structures at low temperatures (80 K) indicate that the electrons generated by the ionizing radiation are mobile and will move rapidly under the application of an external electric field. Holes, on the other hand, that would normally move in the opposite direction through the SiO2 via a "thermal hopping" process, are effectively immobile at low electric fields as they are trapped close to their generation sites. However, for sufficiently large electric fields (greater than 3 MV/cm) holes are able to move through the SiO2. The larger the field, the more rapidly the holes move. The separation of the electrons and holes leads to a reduced electric field within the insulating layer. To overcome this reduction in electric field, a greater external voltage will have to be applied that alters the normal operation of the device. This report presents the results of radiation testing of the MSA at 60 K. The temperature was higher than the targeted temperature because of a faulty electrical interconnect on the test board. Specifically, our goal was to determine whether the MSA would function propey after a TID of 200 krad(Si)

Human knee joint finite element model using a two bundle anterior cruciate ligament: Validation and gait analysis

Anterior cruciate ligament (ACL) deficient individuals are at a much higher risk of developing osteoarthritis (OA) compared to those with intact ACLs, likely due to altered biomechanical loading [1]. Research indicates the ACL is comprised of two “bundles”, the anteromedial (AM) and posterolateral (PL) bundles [2]. Although the function of both bundles is to restrain anterior tibial translation (ATT), each bundle has their own distinct range of knee flexion where they are most effective [3]. Articular cartilage contact stress measurements are difficult to measure in vivo. An alternative approach is to use knee joint finite element models (FEMs) to predict soft tissue stresses and strains throughout the knee. Initial and boundary conditions for these FEMs may be determined from knee joint kinematics estimated from motion analysis experiments. However, there is a lack of knee joint FEMs which include both AM and PL bundles to predict changes to articular cartilage contact pressures resulting from ACL injuries. The purpose of this study is to develop and validate a knee joint FEM using both AM and PL bundles and subsequently perform a gait analysis of varying ACL injuries

Exploring patient information needs in type 2 diabetes: A cross sectional study of questions

This study set out to analyze questions about type 2 diabetes mellitus (T2DM) from patients and the public. The aim was to better understand people's information needs by starting with what they do not know, discovered through their own questions, rather than starting with what we know about T2DM and subsequently finding ways to communicate that information to people affected by or at risk of the disease. One hundred and sixty-four questions were collected from 120 patients attending outpatient diabetes clinics and 300 questions from 100 members of the public through the Amazon Mechanical Turk crowdsourcing platform. Twenty-three general and diabetes-specific topics and five phases of disease progression were identified; these were used to manually categorize the questions. Analyses were performed to determine which topics, if any, were significant predictors of a question's being asked by a patient or the public, and similarly for questions from a woman or a man. Further analysis identified the individual topics that were assigned significantly more often to the crowdsourced or clinic questions. These were Causes (CI: [-0.07, -0.03], p < .001), Risk Factors ([-0.08, -0.03], p < .001), Prevention ([-0.06, -0.02], p < .001), Diagnosis ([-0.05, -0.02], p < .001), and Distribution of a Disease in a Population ([-0.05,-0.01], p = .0016) for the crowdsourced questions and Treatment ([0.03, 0.01], p = .0019), Disease Complications ([0.02, 0.07], p < .001), and Psychosocial ([0.05, 0.1], p < .001) for the clinic questions. No highly significant gender-specific topics emerged in our study, but questions about Weight were more likely to come from women and Psychosocial questions from men. There were significantly more crowdsourced questions about the time Prior to any Diagnosis ([(-0.11, -0.04], p = .0013) and significantly more clinic questions about Health Maintenance and Prevention after diagnosis ([0.07. 0.17], p < .001). A descriptive analysis pointed to the value provided by the specificity of questions, their potential to disclose emotions behind questions, and the as-yet unrecognized information needs they can reveal. Large-scale collection of questions from patients across the spectrum of T2DM progression and from the public-a significant percentage of whom are likely to be as yet undiagnosed-is expected to yield further valuable insights

Low Temperature (30 K) TID Test Results of a Radiation Hardened 128 Channel Serial-to-Parallel Converter

This viewgraph presentation reviews the low temperature, Total Ionizing Dose (TID) tests of radiation hardened serial to parallel converter to be used on the James Webb Space Telescope. The test results show that the original HV583 level shifter - a COTS part -was not suitable for JWST because the supply currents exceeded specs after 20 krad( Si) .The HV584 - functionally similar to the HV583 -was designed using RHBD approach that reduced the leakage currents to within acceptable levels and had only a small effect on the level-shifted output voltage

In situ observation of calcium oxide treatment of inclusions in molten steel by confocal microscopy

Calcium treatment of aluminum killed steel was observed in situ using high-temperature confocal scanning laser microscope (HT-CSLM). This technique along with a novel experimental design enables continuous observation of clustering behavior of inclusions before and after the calcium treatment. Results show that the increase in average inclusion size in non-calcium-treated condition was much faster compared to calcium-treated condition. Results also show that the magnitude of attractive capillary force between inclusion particles in non-treated condition was about 10−15 N for larger particles (10 µm) and 10−16 N for smaller particles (5 µm) and acting length of force was about 30 µm. In the case of calcium-treated condition, the magnitude and acting length of force was reduced to 10−16 N and 10 µm, respectively, for particles of all sizes. This change in attractive capillary attractive force is due to change in inclusion morphology from solid alumina disks to liquid lens particles during calcium treatment

Practice Characteristics and Job Satisfaction of Private Practice and Academic Surgeons

IMPORTANCE: Private practice and academic surgery careers vary significantly in their daily routine, compensation schemes, and definition of productivity. Data are needed regarding the practice characteristics and job satisfaction of these career paths for surgeons and trainees to make informed career decisions and to identify modifiable factors that may be associated with the health of the surgical workforce. OBJECTIVE: To obtain and compare the differences in practice characteristics and career satisfaction measures between academic and private practice surgeons. DESIGN, SETTING, AND PARTICIPANTS: In this cross-sectional survey performed from June 4 to August 1, 2018, an online survey accommodating smartphone, tablet, and desktop formats was distributed by email to 25 748 surgeons who were actively practicing fellows of the American College of Surgeons; had completed a general surgery residency or categorical fellowship in plastic, cardiothoracic, or vascular surgery; and had an active email address on file. MAIN OUTCOMES AND MEASURES: Demographic, training, and current practice characteristics were obtained, and satisfaction measures were measured on a 5-point Likert scale and compared by surgeon type. Nonresponse weights adjusted for respondent sex, age, and presence of subspecialty training between respondents and the total surveyed American College of Surgeons population. RESULTS: There were 3807 responses (15% response rate) from surgeons: 1735 academic surgeons (1390 men [80%]; median age, 53 years [interquartile range (IQR), 44-61 years]) and 1464 private practice surgeons (1276 men [87%]; median age, 56 years [IQR, 48-62 years]); 589 surgeons who reported being neither an academic surgeon nor a private practice surgeon and 19 surgeons who did not respond to questions on their practice type were excluded. Academic surgeons reported working a median of 59 hours weekly (IQR, 38-65 hours) compared with 57 hours weekly (IQR, 45-65 hours) for private practice surgeons. Academic surgeons reported more weekly hours performing nonclinical work than did private practice surgeons (24 hours [IQR, 14-38 hours] vs 9 hours [IQR, 4-17 hours]; P < .001). Academic surgeons were more likely than private practice surgeons to be satisfied with their career as a surgeon (1448 of 1706 [85%] vs 1109 of 1420 [78%]; P < .001) and their financial compensation (997 of 1703 [59%] vs 546 of 1416 [39%]; P < .001). Academic surgeons were less likely than private practice surgeons to feel that competition with other surgeons is a threat to financial security (341 of 1705 [20%] vs 559 of 1422 [39%]; P < .001) and less likely to feel that malpractice experience has decreased job satisfaction (534 of 1703 [31%] vs 686 of 1413 [49%]; P < .001). CONCLUSIONS AND RELEVANCE: This study suggests that, although overall surgeon satisfaction was high, academic surgeons reported higher career satisfaction on several measures when compared with private practice surgeons. Advocacy for private practice surgeons is important to encourage career longevity and sustain US surgeon workforce needs

Whitefield News

File includes: January 2016 Volume 3, Issue 7 February 2016 Volume 3, Issue 8 March 2016 Volume 3, Issue 9 April 2016 Volume 3, Issue 10 May 2016 Volume 3, Issue 11 June 2016 Volume 3, Issue 12 July 2016 Volume 4, Issue 1 August 2016 Volume 4, Issue 2 September 2016, Volume 4, Issue 3 October 2016, Volume 4, Issue 4 November 2016, Volume 4, Issue 5 December 2016, Volume 4, Issue