Considerations of some critical ejector problems

Some aspects of ejector design and application, including, three dimensional effects and cross flow effects are presented

Jet-diffuser Ejector - Attached Nozzle Design

Attached primary nozzles were developed to replace the detached nozzles of jet-diffuser ejectors. Slotted primary nozzles located at the inlet lip and injecting fluid normal to the thrust axis, and rotating the fluid into the thrust direction using the Coanda Effect were investigated. Experiments indicated excessive skin friction or momentum cancellation due to impingement of opposing jets resulted in performance degradation. This indicated a desirability for location and orientation of the injection point at positions removed from the immediate vicinity of the inlet surface, and at an acute angle with respect to the thrust axis. Various nozzle designs were tested over a range of positions and orientations. The problems of aircraft integration of the ejector, and internal and external nozzle losses were also considered and a geometry for the attached nozzles was selected. The effect of leaks, protrusions, and asymmetries in the ejector surfaces was examined. The results indicated a relative insensitivity to all surface irregularities, except for large protrusions at the throat of the ejector

A Jet-diffuser ejector for a V/STOL fighter

A single ejector equipped with only one vector control jet and a diffuser flap was installed close to the leading edge of the strake of a one-fifth scale, semi-span model of the aircraft, without wing, canard, or tail surface. Tests of the system at a nozzle pressure ratio of 1.24 indicated a thrust augmentation of 1.92 and a thrust in the flight direction of about 12% of the total thrust under static conditions. An ejector stall occured at a ratio of tunnel dynamic pressure to nozzle gage pressure of about 0.008. Ejector stall speed can be delayed by using a boundary layer control jet at the front inlet lip of the ejector

The Learning Agenda 2.0: An Approach to Facilitate Systems Change

Background: The public health (PH) workforce is currently facing many complex challenges that stand at the root of community health issues (e.g., racism, poverty, mental health). Existing PH workforce development models focus largely on improving individual competency, but individual competency alone cannot address these complex challenges at the individual, organizational, community, and systems levels. Developing the necessary cross-cutting skills (e.g., systems thinking, persuasive communication, problem solving) requires a new approach to training and learning. Method: The Public Health Learning Agenda for Systems Change (PHLASC) helps public health organizations and their partners use transformative, collective learning as a driver for systems change. By working through multiple learning approaches and learning opportunities focused on a community or systems challenge, PH and community partners can develop a Learning Agenda that will lead to systems change. Developed by the HRSA-funded Public Health Training Centers and the University of Illinois at Chicago Policy, Practice and Prevention Research Center, the PHLASC calls on workforce development specialists, public health practitioners and their partners to shift their “starting point” for developing learning. Rather than developing learning in response to individual competency gaps, the Learning Agenda begins with defining the challenge standing at the root of the community health issue to be addressed. Results: During the summer of 2021, 24 organizations of varying size and focus field-tested the Learning Agenda. Results from the pilot study were reviewed by a national Steering Committee who provided recommendations for improvements. These recommendations and examples of the Learning Agenda’s earliest uses will be shared. Conclusion: This interactive workshop will introduce the PHLASC and tools available to support workforce development specialists and PH professionals. Following a brief presentation of the Learning Framework and concept of the PHLASC, participants will work individually and in small groups to practice using the Learning Agenda Toolkit

A Region-Wide Field Placement Program Built on the Foundation of Mentorship and Professionalism

Background: The Region IV Public Health Training Center (R-IV PHTC) provides public health students from the eight states of HHS Region IV with essential practice experiences that demonstrate the value of working with underserved populations. The Pathways to Practice Scholars field placement program is built on a foundation of mentorship, professionalism, and community. Methods: Sixteen student scholars (13 graduate; 3 undergraduate) were selected to work during May-August 2015 in practiceoriented agencies serving underserved populations. Each scholar received a $1500 living allowance. Seven of 16 accepted an internship outside the state of their university. In conjunction with mentors, Scholars developed work plans based on Council on Linkages Core Competency domains. Requirements included a pre-, mid- and post-assessment, an executive summary/reflection, and a virtual webinar presentation. Results: Student Scholars worked at sites across eight states in state or local health departments, Area Health Education Centers (AHECs), and healthcare settings. Students identified Core Competency domains they developed most during the field placement: Communication, Analytical/Assessment, Leadership/Systems Thinking, and Community Engagement. The R-IV PHTC asked mentors to treat interns as valued employees and include them in activities beyond their specific project. Indicators of successful mentorship included expressed appreciation for student assistance and the desire to enrich the student experience while benefiting the agency mission. Mentors provided clearly defined projects for a short timeframe (10-12 weeks), adjusted to the students’ capacity and readiness, and offered opportunities to apply classroom skills to practice. They helped students develop immediately useful products in collaboration with community stakeholders. Conclusions: Mentors play a crucial role in the development and success of field placement students, but students and mentors share equal responsibility in fostering the relationship. Past case studies from this program demonstrate that some students find employment in these same agencies after graduation, and become mentors for future students, thus, creating a self-perpetuating learning community

Meeting the Public Health Workforce’s Training Priorities in Georgia and the Southeast

Background: The mission of the Region IV Public Health Training Center (R-IV PHTC) is to build knowledge and skills in the public health workforce in the eight states of HHS Region IV by providing competency-based training. Workforce training needs are changing quickly and dramatically in light of new developments in public health practice and science, emerging diseases, changes in the health care environment, and the growing emphasis on inter-professional practice. Additionally, a 2014 survey conducted by the Association of State and Territorial Health Officials (ASTHO) found that at least 38% of the current public health workforce plans to retire by 2020. Therefore, it is increasingly crucial to prepare upcoming managers for leadership positions and to train entry-level workers to assume more advanced roles. Methods: To address current and emerging training needs in Georgia and the southeast, the R-IV PHTC continually identifies emerging priorities and effective training approaches. It explores training needs through a review of formal needs assessments, key stakeholder interviews, surveys of targeted audiences, informal partner communications, and training evaluation data. An interactive component of the GPHA session allowed participants to identify and discuss their own professional training needs. Results: Workforce development needs assessments data across several southeastern states identified recurring training needs for professionals in Tiers 1, 2 and 3 of the Council on Linkages Core Competency domains for Analytical/Assessment Skills and Financial Planning/Management. In Georgia, top competency training needs gathered from a variety of assessment methods included Cultural Competency, Communication, Financial Planning/Management, Public Health Science, and Leadership/Systems Thinking. Participants in the workshop’s interactive component expressed highest personal need for training in Financial Planning/Management, Analytical/Assessment Skills, and Policy Development/Program Planning. However, for others in their organizations, they identified a priority need for leadership training. Conclusions: The R-IV PHTC assesses training needs and provides training resources to respond to current and emerging public health workforce development needs in Georgia and the southeast

LDA+DMFT computation of the electronic spectrum of NiO

The electronic spectrum, energy gap and local magnetic moment of paramagnetic NiO are computed by using the local density approximation plus dynamical mean-field theory (LDA+DMFT). To this end the noninteracting Hamiltonian obtained within the local density approximation (LDA) is expressed in Wannier functions basis, with only the five anti-bonding bands with mainly Ni 3d character taken into account. Complementing it by local Coulomb interactions one arrives at a material-specific many-body Hamiltonian which is solved by DMFT together with quantum Monte-Carlo (QMC) simulations. The large insulating gap in NiO is found to be a result of the strong electronic correlations in the paramagnetic state. In the vicinity of the gap region, the shape of the electronic spectrum calculated in this way is in good agreement with the experimental x-ray-photoemission and bremsstrahlung-isochromat-spectroscopy results of Sawatzky and Allen. The value of the local magnetic moment computed in the paramagnetic phase (PM) agrees well with that measured in the antiferromagnetic (AFM) phase. Our results for the electronic spectrum and the local magnetic moment in the PM phase are in accordance with the experimental finding that AFM long-range order has no significant influence on the electronic structure of NiO.Comment: 15 pages, 6 figures, 1 table; published versio

Quantum computer-aided design of quantum optics hardware

The parameters of a quantum system grow exponentially with the number of involved quantum particles. Hence, the associated memory requirement to store or manipulate the underlying wavefunction goes well beyond the limit of the best classical computers for quantum systems composed of a few dozen particles, leading to serious challenges in their numerical simulation. This implies that the verification and design of new quantum devices and experiments are fundamentally limited to small system size. It is not clear how the full potential of large quantum systems can be exploited. Here, we present the concept of quantum computer designed quantum hardware and apply it to the field of quantum optics. Specifically, we map complex experimental hardware for high-dimensional, many-body entangled photons into a gate-based quantum circuit. We show explicitly how digital quantum simulation of Boson sampling experiments can be realized. We then illustrate how to design quantum-optical setups for complex entangled photonic systems, such as high-dimensional Greenberger-Horne-Zeilinger states and their derivatives. Since photonic hardware is already on the edge of quantum supremacy and the development of gate-based quantum computers is rapidly advancing, our approach promises to be a useful tool for the future of quantum device design

Factors that control the stable carbon isotopic composition of methane produced in an anoxic marine sediment

The carbon isotopic composition of methane produced in anoxic marine sediment is controlled by four factors: (1) the pathway of methane formation, (2) the isotopic composition of the methanogenic precursors, (3) the isotope fractionation factors for methane production, and (4) the isotope fractionation associated with methane oxidation. The importance of each factor was evaluated by monitoring stable carbon isotope ratios in methane produced by a sediment microcosm. Methane did not accumulate during the initial 42-day period when sediment contained sulfate, indicating little methane production from 'noncompetitive' substrates. Following sulfate depletion, methane accumulation proceeded in three distinct phases. First, CO2 reduction was the dominant methanogenic pathway and the isotopic composition of the methane produced ranged from -80 to -94 per thousand. The acetate concentration increased during this phase, suggesting that acetoclastic methanogenic bacteria were unable to keep pace with acetate production. Second, acetate fermentation became the dominant methanogenic pathway as bacteria responded to elevated acetate concentrations. The methane produced during this phase was progressively enriched in C-13, reaching a maximum delta(C-13) value of -42 per thousand. Third, the acetate pool experienced a precipitous decline from greater than 5 mM to less than 20 micro-M and methane production was again dominated by CO2 reduction. The delta(C-13) of methane produced during this final phase ranged from -46 to -58 per thousand. Methane oxidation concurrent with methane production was detected throughout the period of methane accumulation, at rates equivalent to 1 to 8 percent of the gross methane production rate. Thus methane oxidation was too slow to have significantly modified the isotopic signature of methane. A comparison of microcosm and field data suggests that similar microbial interactions may control seasonal variability in the isotopic composition of methane emitted from undisturbed Cape Lookout Bight sediment