6,760 research outputs found
Study of advanced rotary combustion engines for commuter aircraft
Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed
Testing of a one-bladed 30-meter-diameter rotor on the DOE/NASA Mod-O wind turbine
Tests were conducted on the DOE/NASA Mod-O 200-kW horizontal-axis wind turbine in a one-bladed rotor configuration. The objectives of the test were to evaluate the performance, loads, and dynamic characteristics of a one-bladed rotor, and then to compare these parameters with those of an aerodynamically similar two-bladed rotor configuration. Test operations showed that this intermediate-size (15.2-m radius) one-bladed rotor configuration can be operated successfully. Test results show that the one-bladed rotor had cyclic blade loads comparable to those of a two-bladed rotor. A moderate power penalty equivalent to a reduction in windspeed of 1 m/sec occurred with the one-bladed rotor when operated at a rotor speed 50 percent higher than that of the two-bladed rotor
Performance, emissions, and physical characteristics of a rotating combustion aircraft engine
The RC2-75, a liquid cooled two chamber rotary combustion engine (Wankel type), designed for aircraft use, was tested and representative baseline (212 KW, 285 BHP) performance and emissions characteristics established. The testing included running fuel/air mixture control curves and varied ignition timing to permit selection of desirable and practical settings for running wide open throttle curves, propeller load curves, variable manifold pressure curves covering cruise conditions, and EPA cycle operating points. Performance and emissions data were recorded for all of the points run. In addition to the test data, information required to characterize the engine and evaluate its performance in aircraft use is provided over a range from one half to twice its present power. The exhaust emissions results are compared to the 1980 EPA requirements. Standard day take-off brake specific fuel consumption is 356 g/KW-HR (.585 lb/BHP-HR) for the configuration tested
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A cross-cultural look at serving the public interest: American and Israeli journalists consider ethical scenarios
This study explores how the social dimensions of a reporter’s world shape ethical decisions through parallel surveys of daily newspaper reporters in Israel and one Midwestern US state. Through regression analysis, we found that personal factors (gender, years of education) were not related to ethical decisions nor were professional factors (professional experience, professional membership, having studied journalism). In contrast, the social context element (country of practice) was relevant for two of three ethical situations. We also found that personal, professional and social dimensions varied in their utility to ethical decision-making from situation to situation. Considering a reporter’s ethical predisposition, this study found that personal value systems may be more important for ethical decision-making than formal written codes. This study suggests that ethical foundations shared across nations can create cultural bridges – but that diverging ethical perspectives also may create journalistic barriers
Monte Carlo simulations of ordering in ferromagnetic-antiferromagnetic bilayers
Monte Carlo simulations have been used to study phase transitions on coupled
anisotropic ferro/antiferromagnetic (FM/AFM) films of classical Heisenberg
spins. We consider films of different thicknesses, with fully compensated
exchange across the FM/AFM interface. We find indications of a phase transition
on each film, occuring at different temperatures. It appears that both
transition temperatures depend on the film thickness.Comment: Revtex, 4 pages, 4 figure
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ATHENA: A Phase 3, Open-Label Study Of The Safety And Effectiveness Of Oliceridine (TRV130), A G-Protein Selective Agonist At The µ-Opioid Receptor, In Patients With Moderate To Severe Acute Pain Requiring Parenteral Opioid Therapy.
Background:Pain management with conventional opioids can be challenging due to dose-limiting adverse events (AEs), some of which may be related to the simultaneous activation of β-arrestin (a signaling pathway associated with opioid-related AEs) and G-protein pathways. The investigational analgesic oliceridine is a G-protein-selective agonist at the µ-opioid receptor with less recruitment of β-arrestin. The objective of this phase 3, open-label, multi-center study was to evaluate the safety and tolerability, of IV oliceridine for moderate to severe acute pain in a broad, real-world patient population, including postoperative surgical patients and non-surgical patients with painful medical conditions. Methods:Adult patients with a score ≥4 on 11-point NRS for pain intensity received IV oliceridine either by bolus or PCA; multimodal analgesia was permitted. Safety was assessed using AE reports, study discontinuations, clinical laboratory and vital sign measures. Results:A total of 768 patients received oliceridine. The mean age (SD) was 54.1 (16.1) years, with 32% ≥65 years of age. Most patients were female (65%) and Caucasian (78%). Surgical patients comprised the majority of the study population (94%), most common being orthopedic (30%), colorectal (15%) or gynecologic (15%) procedures. Multimodal analgesia was administered to 84% of patients. Oliceridine provided a rapid reduction in NRS pain score by 2.2 ± 2.3 at 30 mins from a score of 6.3 ± 2.1 (at baseline) which was maintained to the end of treatment. No deaths or significant cardiorespiratory events were reported. The incidence of AEs leading to early discontinuation and serious AEs were 2% and 3%, respectively. Nausea (31%), constipation (11%), and vomiting (10%) were the most common AEs. AEs were mostly of mild (37%) or moderate (25%) severity and considered possibly or probably related to oliceridine in 33% of patients. Conclusion:Oliceridine IV for the management of moderate to severe acute pain was generally safe and well tolerated in the patients studied. ClinicalTrialsgov identifier:NCT02656875
Job Growth in Early Transition: Comparing Two Paths
Small start-up firms are the engine of job creation in early transition and yet little is known about the characteristics of this new sector. We seek to identify patterns of job growth in this sector in terms of niches left from central planning and ask about differences in job creation across two different transition economies: Estonia, which experienced rapid destruction of the pre-existing firms, and the Czech Republic, which reduced the old sector gradually. We find job growth within industries to be quantitatively more important than job growth due to across-industry reallocation. Furthermore, the industrial composition of startups is strikingly similar in the two countries. We offer convergence to "western" industry firm-size distributions as an explanation. We also find regularities in wage evolution across new and old firms, including small differences in job quality across the two transition paths.http://deepblue.lib.umich.edu/bitstream/2027.42/39888/3/wp503.pd
The discovery of rivaroxaban: translating preclinical assessments into clinical practice
Direct oral anticoagulants that target a single coagulation factor (such as factor Xa or thrombin) have been developed in recent years in an attempt to address some of the limitations of traditional anticoagulants. Rivaroxaban is an oral, direct factor Xa inhibitor that inhibits free and clot-bound factor Xa and factor Xa in the prothrombinase complex. Preclinical studies demonstrated a potent anticoagulant effect of rivaroxaban in plasma as well as the ability of this agent to prevent and treat venous and arterial thrombosis in animal models. These studies led to an extensive phase I clinical development program that investigated the pharmacological properties of rivaroxaban in humans. In these studies, rivaroxaban was shown to exhibit predictable pharmacokinetics and pharmacodynamics and to have no clinically relevant interactions with many commonly prescribed co-medications. The pharmacodynamic effects of rivaroxaban (for example, inhibition of factor Xa and prolongation of prothrombin time) were closely correlated with rivaroxaban concentrations in plasma. The encouraging findings from preclinical and early clinical studies were expanded upon in large, randomized phase III studies, which demonstrated the clinical efficacy and safety of rivaroxaban in a broad spectrum of patients. This article provides an overview of the discovery and development of rivaroxaban, describing the pharmacodynamic profile established in preclinical studies and the optimal translation to clinical studies in healthy subjects and patient populations
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