A triangular thin shell finite element: Linear analysis

The formulation of the linear stiffness matrix for a doubly-curved triangular thin shell element, using a modified potential energy principle, is described. The strain energy component of the potential energy is expressed in terms of displacements and displacement gradients by use of consistent Koiter strain-displacement equations. The element inplane and normal displacement fields are approximated by complete cubic polynomials. The interelement displacement admissibility conditions are met in the global representation by imposition of constraint conditions on the interelement boundaries; the constraints represent the modification of the potential energy. Errors due to the nonzero strains under rigid body motion are shown to be of small importance for practical grid refinements through performance of extensive comparison analyses

Quality improvement at scale: evaluation of the drivers and barriers to adoption and sustainability of an intervention to reduce late referral in chronic kidney disease

This quality improvement project aimed to drive large-scale and sustained change to reduce the burden of chronic kidney disease in the UK. The intervention is a software programme that extracts relevant biochemical data from laboratory databases which then generate graphs of estimated kidney function (eGFR) over time. Graphs showing progressive kidney disease are sent directly back to GPs to alert them to re-review patient care and if necessary, refer to renal services. The aim of this evaluation study was to explain the barriers and drivers to implementation and adoption of the eGFR graph intervention. This evaluation study involved five of the 20 renal units (sites) involved. A Developmental Evaluation approach was utilised. Methods included collection of descriptive data about graph reporting; GP surveys (n=68); focus groups (n=4) with Practices; face-to-face interviews with secondary care clinicians (n=10). Results showed the mean number of graphs reviewed per week per site was 230, taking one hour per week per site. Only 18.2 % graphs highlighted a concerning decline in kidney function. Important enablers to sustain the intervention were low cost, easy to understand, a sense of local ownership and perceived impact. Barriers included nephrologists’ perceived increase in new referrals. We concluded that developmental evaluation can explain the barriers/drivers to implementation of a national quality improvement project that involves a variety of different stakeholders. The intervention has the potential to slow down progression of kidney disease due to the eGFR prompts alerting GPs to review the patient record and take action, such as reviewing medications and referring to renal teams if progressive kidney disease had not been identified previously

Subsonic Swept Fan Blade

A gas turbine engine includes a spool, a turbine coupled to drive the spool, a propulsor coupled to be driven at a at a design speed by the turbine through the spool, and a gear assembly coupled between the propulsor and the spool. Rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extend from the hub. Each of the propulsor blades includes an airfoil body. The leading edge of the airfoil body has a swept profile such that, at the design speed, a component of a relative velocity vector of a working gas that is normal to the leading edge is subsonic along the entire radial span

Shear buckling of square perforated plates

The behavior of thin square perforated plates under the action of uniform shear deformation is studied experimentally and analytically using finite element analysis. Elastic Shear buckling strength is established as a function of the diameter of a round, centrally located hole in the plate. Post buckling behavior and the behavior of perforated plates with various ring stiffeners are also studied experimentally

Error Disclosure Training and Organizational Culture

Objective. Our primary objective was to determine whether, after training was offered to participants, those who indicated they had received error disclosure training previously were more likely to disclose a hypothetical error and have more positive perceptions of their organizational culture pertaining to error disclosure, safety, and teamwork. Methods. Across a 3-year span, all clinical faculty from six health institutions (four medical schools, one cancer center, and one health science center) in The University of Texas System were offered the opportunity to anonymously complete an electronic survey focused on measuring error disclosure culture, safety culture, teamwork culture, and intention to disclose a hypothetical error at two time points—both before (baseline) and after (follow-up) disclosure training was conducted for a subset of faculty. Results. There were significant improvements (all p-values \u3c .05) in the follow-up surveys compared with the baseline surveys for the following domains (percent refers to percent positives before and after, respectively): minor error disclosure culture (33 percent vs. 52 percent), serious error disclosure (53 percent vs. 70 percent), safety culture (50 percent vs. 63 percent), and teamwork culture (62 percent vs. 73 percent). Follow-up survey data revealed significant differences (all p-values \u3c .001) between faculty who had previously received any error disclosure training (n = 472) and those who had not (n = 599). Specifically, we found significant differences in culture (all p-values \u3c .001) between those who received any error disclosure training and those who did not for all culture domains: minor error disclosure (61 percent vs. 41 percent), serious error disclosure (79 percent vs. 58 percent), trust-based error disclosure (61 percent vs. 51 percent), safety (73 percent vs. 51 percent), and teamwork (78 percent vs. 66 percent). Significant differences also existed for intent to disclose an error (t = 4.1, p \u3c .05). We also found that error disclosure culture was significantly associated with intent to disclose for those who received previous error disclosure training, whereas all types of culture we measured were significantly associated with intent to disclose for those who did not receive error disclosure training. Conclusions. Error disclosure, teamwork, and safety culture all improved over a 3-year period during which disclosure training was provided to key faculty in these six institutions. Self‑reported likelihood to disclose errors also improved. The precise impact of the training on these improvements cannot be determined from this study; nevertheless, we present an approach to measuring error disclosure culture and providing training that may be useful to other institutions

Cooling and Trapping of Atomic Strontium

We present a detailed investigation of strontium magneto-optical trap (MOT) dynamics. Relevant physical quantities in the trap, such as temperature, atom number and density, and loss channels and lifetime, are explored with respect to various trap parameters. By studying the oscillatory response of a two-level 1S0–1P1 88Sr MOT, we firmly establish the laser cooling dynamics predicted by Doppler theory. Measurements of the MOT temperature, however, deviate severely from Doppler theory predictions, implying significant additional heating mechanisms. To explore the feasibility of attaining quantum degenerate alkaline-earth samples via evaporative cooling, we also present the first experimental demonstration of magnetically trapped metastable 88Sr. Furthermore, motivated by the goal of establishing the fermionic isotope 87Sr as one of the highest-quality, neutral-atom-based optical frequency standards, we present a preliminary study of sub-Doppler cooling in a 87Sr MOT. A dual-isotope (87Sr and 88Sr) MOT is also demonstrated

Millimeter wave satellite concepts. Volume 1: Executive summary

The objectives of the program were: (1) development of methodology based on the technical requirements of potential services that might be assigned to millimeter wave bands for identifying the viable and appropriate technologies for future NASA millimeter research and development programs, and (2) testing of this methodology with user applications and services. The scope of the program included the entire communications network, both ground and space subsystems. The reports include: (1) cost, weight, and performance models for the subsystems, (2) conceptual design for point-to-point and broadcast communications satellites, (3) analytic relationships between subsystem parameters and an overall link performance, (4) baseline conceptual systems, (5) sensitivity studies, (6) model adjustment analyses, (7) identification of critical technologies and their risks, (8) brief R&D program scenarios for the technologies judged to be moderate or extensive risks

Patient safety and the ageing physician: a qualitative study of key stakeholder attitudes and experiences

Background Unprecedented numbers of physicians are practicing past age 65. Unlike other safety-conscious industries, such as aviation, medicine lacks robust systems to ensure late-career physician (LCP) competence while promoting career longevity. Objective To describe the attitudes of key stakeholders about the oversight of LCPs and principles that might shape policy development. Design Thematic content analysis of interviews and focus groups. Participants 40 representatives of stakeholder groups including state medical board leaders, institutional chief medical officers, senior physicians (\u3e65 years old), patient advocates (patients or family members in advocacy roles), nurses and junior physicians. Participants represented a balanced sample from all US regions, surgical and non-surgical specialties, and both academic and non-academic institutions. Results Stakeholders describe lax professional self-regulation of LCPs and believe this represents an important unsolved challenge. Patient safety and attention to physician well-being emerged as key organising principles for policy development. Stakeholders believe that healthcare institutions rather than state or certifying boards should lead implementation of policies related to LCPs, yet expressed concerns about resistance by physicians and the ability of institutions to address politically complex medical staff challenges. Respondents recommended a coaching and professional development framework, with environmental changes, to maximise safety and career longevity of physicians as they age. Conclusions Key stakeholders express a desire for wider adoption of LCP standards, but foresee significant culture change and practical challenges ahead. Participants recommended that institutions lead this work, with support from regulatory stakeholders that endorse standards and create frameworks for policy adoption

Dynamics in a Two-Level Atom Magneto-Optical Trap

Alkaline-earth-metal atoms present an ideal platform for exploring magneto-optic trap (MOT) dynamics, enabling unique and definitive tests of laser cooling and trapping mechanisms. We have measured the trapping beam intensity, detuning, magnetic-field gradient, trap density, and lifetime dependence of the spring constant κ and damping coefficient α for a 1S0−1P1 88Sr MOT by fitting the oscillatory response of the atom cloud to a step-function force. We find that the observed behavior of κ and α provide a unified and consistent picture of trap dynamics that agrees with Doppler cooling theory at the level of 10%.Additionally, we demonstrate that the trapped atom temperature can be determined directly from measured value of κ and the trap size, in excellent agreement with free-expansion temperature measurements. However, the experimentally determined temperature is much higher than Doppler cooling theory, implying significant additional heating mechanisms

Single-Stage Sub-Doppler Cooling of Alkaline Earth Atoms

We report the first experimental study of sub-Doppler cooling in alkaline earth atoms (87Sr) enabled by the presence of nuclear spin-originated magnetic degeneracy in the atomic ground state. Sub-Doppler cooling in a σ+-σ− configuration is achieved despite the presence of multiple, closely spaced excited states. This surprising result is confirmed by an expanded multilevel theory of the radiative cooling force. Detailed investigations of system performance have shed new insights into (σ+-σ−) cooling dynamics and will likely play an important role in the future development of neutral atom-based optical frequency standards