28 research outputs found

    Composite Elastic Skins for Shape-Changing Structures

    Get PDF
    Composite elastic skins having tailorable mechanical properties have been invented for covering shape-changing ( morphable ) structures. These skins are intended especially for use on advanced aircraft that change shapes in order to assume different aerodynamic properties. Many of the proposals for aircraft that could perform large aerodynamic shape changes require flexible skins that could follow shape changes of internal structures driven by actuators. Examples of such shape changes can include growth or shrinkage of bumps, conformal changes in wing planforms, cambers, twists, and bending of integrated leading- and trailing-edge flaps. Prior to this invention, there was no way of providing smooth aerodynamic surfaces capable of large deflections while maintaining smoothness and sufficient rigidity. Although latex rubber, silicone rubber, and similar conventional materials can be made into smooth coverings, they are not suitable for this purpose because, in order to impart required stiffness against out-of-plane bending, it would be necessary to make the coverings excessively thick, thereby necessitating the use of impractically large actuation forces. The basic idea of the invention is that of smoothly wrapping an underlying variable structure with a smooth skin that can be stretched or otherwise warped with low actuation force in one or both in-plane direction(s) and is relatively stiff against out-of-plane bending. It is envisioned that a skin according to the invention could be stretched as much as 20 percent in a desired direction. Because this basic idea admits of numerous variations, the following description is necessarily oversimplified for the sake of brevity

    Flexible Volumetric Structure

    Get PDF
    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure

    NASA High-Reynolds Number Circulation Control Research - Overview of CFD and Planned Experiments

    Get PDF
    A new capability to test active flow control concepts and propulsion simulations at high Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center is being developed. This technique is focused on the use of semi-span models due to their increased model size and relative ease of routing high-pressure air to the model. A new dual flow-path high-pressure air delivery station has been designed, along with a new high performance transonic sem -si pan wing model. The modular wind tunnel model is designed for testing circulation control concepts at both transonic cruise and low-speed high-lift conditions. The ability of the model to test other active flow control techniques will be highlighted. In addition, a new higher capacity semi-span force and moment wind tunnel balance has been completed and calibrated to enable testing at transonic conditions

    Nursing Home Staff Palliative Care Knowledge and Practices: Results of a Large Survey of Frontline Workers

    Get PDF
    CONTEXT: Deficits in quality end-of-life care for nursing home (NH) residents are well known. Palliative care is promoted as an approach to improve quality. The Palliative Care Survey (PCS) is designed to measure NH staff palliative care knowledge and practice. OBJECTIVES: To comparing palliative care knowledge and practices across NH staff roles using the PCS, and to examine relationships between facility characteristics and PCS scores. METHODS: The PCS was administered to frontline NH staff-certified nursing assistants (CNAs), licensed practical nurses (LPNs), registered nurses (RNs), and social workers (SWs)-in 51 facilities in 2012. Descriptive statistics were calculated by job role. Linear mixed effects models were used to identify facility and individual factors associated with palliative care practice and knowledge. RESULTS: The analytic sample included 1200 surveys. CNAs had significantly lower practice and knowledge scores compared to LPNs, RNs, and SWs (P < 0.05). LPNs had significantly lower psychological, end-of-life, and total knowledge scores than RNs (P < 0.05 for all). Although knowledge about physical symptoms was uniformly high, end-of-life knowledge was notably low for all staff. A one-point higher facility star rating was significantly associated with a 0.06 increase in family communication score (P = 0.003; 95% CI: 0.02-0.09; SE = 0.02). Higher penetration of hospice in the NH was associated with higher end-of-life knowledge (P = 0.003; parameter estimate = 0.006; 95% CI: 0.002-0.010; SE = 0.002). Sixty-two percent of respondents stated that, with additional training, they would be interested in being leaders in palliative care. CONCLUSION: Given observed differences in palliative care practice and knowledge scores by staff training, it appears the PCS is a useful tool to assess NH staff. Low end-of-life knowledge scores represent an important target for quality improvement

    Hospice in the nursing home: perspectives of front line nursing home staff

    Get PDF
    OBJECTIVE: Use of hospice has been associated with improved outcomes for nursing home residents and attitudes of nursing home staff toward hospice influences hospice referral. The objective of this study is to describe attitudes of certified nursing assistants (CNAs), nurses, and social workers toward hospice care in nursing homes. DESIGN, SETTING, AND PARTICIPANTS: We conducted a survey of 1859 staff from 52 Indiana nursing homes. MEASUREMENTS: Study data include responses to 6 scaled questions and 3 open-ended qualitative prompts. In addition, respondents who cared for a resident on hospice in the nursing home were asked how often hospice: (1) makes their job easier; (2) is responsive when a patient has symptoms or is actively dying; (3) makes care coordination smooth; (4) is needed; (5) taught them something; and (6) is appreciated by patients/families. Responses were dichotomized as always/often or sometimes/never. RESULTS: A total of 1229 surveys met criteria for inclusion. Of the respondents, 48% were CNAs, 49% were nurses, and 3% were social workers; 83% reported caring for a nursing home patient on hospice. The statement with the highest proportion of always/often rating was 'patient/family appreciate added care' (84%); the lowest was 'hospice makes my job easier' (54%). More social workers responded favorably regarding hospice responsiveness and coordination of care compared with CNAs (P = .03 and P = .05, respectively). CONCLUSIONS: A majority of staff responded favorably regarding hospice care in nursing homes. About one-third of nursing home staff rated coordination of care lower than other aspects, and many qualitative comments highlighted examples of when hospice was not responsive to patient needs, representing important opportunities for improvement

    A Sweeping Jet Application on a High Reynolds Number Semispan Supercritical Wing Configuration

    Get PDF
    The FAST-MAC circulation control model was modified to test an array of unsteady sweeping-jet actuators at realistic flight Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center. Two types of sweeping jet actuators were fabricated using rapid prototype techniques, and directed over a 15% chord simple-hinged flap. The model was configured for low-speed high-lift testing with flap deflections of 30 and 60, and a transonic cruise configuration with a 0 flap deflection. For the 30 flap high-lift configuration, the sweeping jets achieved comparable lift performance in the separation control regime, while reducing the mass flow by 54% as compared to steady blowing. However, the sweeping jets were not effective for the 60 flap. For the transonic cruise configuration, the sweeping jets reduced the drag by 3.3% at an off design condition. The drag reduction for the design lift coefficient for the sweeping jets provided only half the drag reduction shown for the steady blowing case (6.5%), but accomplished this with a 74% reduction in mass flow

    Jet Engine Exhaust Nozzle Flow Effector

    Get PDF
    A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip

    Jet Engine Exhaust Nozzle Flow Effector

    Get PDF
    A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip

    Air Data Boom System Development for the Max Launch Abort System (MLAS) Flight Experiment

    Get PDF
    In 2007, the NASA Exploration Systems Mission Directorate (ESMD) chartered the NASA Engineering Safety Center (NESC) to demonstrate an alternate launch abort concept as risk mitigation for the Orion project's baseline "tower" design. On July 8, 2009, a full scale and passively, aerodynamically stabilized MLAS launch abort demonstrator was successfully launched from Wallops Flight Facility following nearly two years of development work on the launch abort concept: from a napkin sketch to a flight demonstration of the full-scale flight test vehicle. The MLAS flight test vehicle was instrumented with a suite of aerodynamic sensors. The purpose was to obtain sufficient data to demonstrate that the vehicle demonstrated the behavior predicted by Computational Fluid Dynamics (CFD) analysis and wind tunnel testing. This paper describes development of the Air Data Boom (ADB) component of the aerodynamic sensor suite

    Does humeral fixation technique affect long-term outcomes of total shoulder arthroplasty?

    Get PDF
    Background For anatomic total arthroscopic repair, cementless humeral fixation has recently gained popularity. However, few studies have compared clinical, radiographic, and patient-reported outcomes between cemented and press-fit humeral fixation, and none have performed follow-up for longer than 5 years. In this study, we compared long-term postoperative outcomes in patients receiving a cemented versus press-fit humeral stem anatomic arthroscopic repair. Methods This study retrospectively analyzed 169 shoulders that required primary anatomic total shoulder arthroplasty (aTSA). Shoulders were stratified by humeral stem fixation technique: cementation or press-fit. Data were collected pre- and postoperatively. Primary outcome measures included range of motion, patient reported outcomes, and radiographic measures. Results One hundred thirty-eight cemented humeral stems and 31 press-fit stems were included. Significant improvements in range of motion were seen in all aTSA patients with no significant differences between final cemented and press-fit stems (forward elevation: P=0.12, external rotation: P=0.60, and internal rotation: P=0.77). Patient reported outcome metrics also exhibited sustained improvement through final follow-up. However, at final follow-up, the press-fit stem cohort had significantly better overall scores when compared to the cemented cohort (visual analog score: P=0.04, American Shoulder and Elbow Surgeon Score: P<0.01, Simple Shoulder Test score: P=0.03). Humeral radiolucency was noted in two cemented implants and one press-fit implant. No significant differences in implant survival were observed between the two cohorts (P=0.75). Conclusions In this series, we found that irrespective of humeral fixation technique, aTSA significantly improves shoulder function. However, within this cohort, press-fit stems provided significantly better outcomes than cemented stems in terms of patient reported outcome scores. Level of evidenceIII
    corecore