611 research outputs found
Baseline performance and emissions data for a single-cylinder, direct-injected diesel engine
Comprehensive fuel consumption, mean effective cylinder pressure, and emission test results for a supercharged, single-cylinder, direct-injected, four-stroke-cycle, diesel test engine are documented. Inlet air-to-exhaust pressure ratios were varied from 1.25 to 3.35 in order to establish the potential effects of turbocharging techniques on engine performance. Inlet air temperatures and pressures were adjusted from 34 to 107 C and from 193 to 414 kPa to determine the effects on engine performance and emissions. Engine output ranged from 300 to 2100 kPa (brake mean effective pressure) in the speed range of 1000 to 3000 rpm. Gaseous and particulate emission rates were measured. Real-time values of engine friction and pumping loop losses were measured independently and compared with motored engine values
Comparison of total body water estimates from O-18 and bioelectrical response prediction equations
Identification of an indirect, rapid means to measure total body water (TBW) during space flight may aid in quantifying hydration status and assist in countermeasure development. Bioelectrical response testing and hydrostatic weighing were performed on 27 subjects who ingested O-18, a naturally occurring isotope of oxygen, to measure true TBW. TBW estimates from three bioelectrical response prediction equations and fat-free mass (FFM) were compared to TBW measured from O-18. A repeated measures MANOVA with post-hoc Dunnett's Test indicated a significant (p less than 0.05) difference between TBW estimates from two of the three bioelectrical response prediction equations and O-18. TBW estimates from FFM and the Kushner & Schoeller (1986) equation yielded results that were similar to those given by O-18. Strong correlations existed between each prediction method and O-18; however, standard errors, identified through regression analyses, were higher for the bioelectrical response prediction equations compared to those derived from FFM. These findings suggest (1) the Kushner & Schoeller (1986) equation may provide a valid measure of TBW, (2) other TBW prediction equations need to be identified that have variability similar to that of FFM, and (3) bioelectrical estimates of TBW may prove valuable in quantifying hydration status during space flight
Random and Correlated Phases of Primordial Gravitaional Waves
The phases of primordial gravity waves is analysed in detail within a quantum
mechanical context following the formalism developed by Grishchuk and Sidorov.
It is found that for physically relevant wavelengths both the phase of each
individual mode and the phase {\it difference} between modes are randomly
distributed. The phase {\it sum} between modes with oppositely directed
wave-vectors, however, is not random and takes on a definite value with no rms
fluctuation. The conventional point of view that primordial gravity waves
appear after inflation as a classical, random stochastic background is also
addressed.Comment: 14 pages, written in REVTE
Eccentric and concentric muscle performance following 7 days of simulated weightlessness
Changes in skeletal muscle strength occur in response to chronic disuse or insufficient functional loading. The purpose of this study was to examine changes in muscle performance of the lower extremity and torso prior to and immediately after 7 days of simulated weightlessness (horizontal bed rest). A Biodex was used to determine concentric and eccentric peak torque and angle at peak torque for the back, abdomen, quadriceps, hamstring, soleus, and tibialis anterior. A reference angle of 0 degrees was set at full extension. Data were analyzed by ANOVA
The role of illness scripts in the development of medical diagnostic expertise: Results from an interview study
In this article, we describe a study in which some current ideas about illness scripts are tested. Participants at 4 levels of medical expertise were asked to describe either a prototypical patient or the clinical picture associated with a number of different diseases. It was found that participants at intermediate levels of expertise mentioned, both absolutely and relatively, many enabling conditions (patient contextual factors such as sex, age, medical history, and occupation) when asked to describe a prototypical patient with a disease, whereas the instruction to describe the clinical picture of a disease revealed a monotonic relation with expertise level. The amount of biomedical information in the descriptions decreased with increasing expertise level for both types of instruction. In addition, a positive relation was found between number of actual patients seen with a particular disease and number of enabling conditions mentioned. These results were interpreted as supportive of the present conceptualization of the illness script theory
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Ecological evaluation of proposed discharge of dredged material from Oakland Harbor into ocean waters (Phase 3 of 38-Foot Project). Volume 1, Background and appendixes A through H
At the request of the US Army Corps of Engineering (USACE), environmental studies were conducted by Battelle/Marine Sciences Laboratory (MSL) to evaluate the suitability of sediments from Oakland Inner Harbor for dredging and ocean disposal. During the Phase 3 38-Foot Project, sediment cores were collected from mudline to {minus}39 ft mean lower low water at various locations in Oakland Inner Harbor channel and allocated to six composite samples. These composites were evaluated through physical/chemical analyses, acute toxicity to sensitive marine organisms, and bioaccumulation potential. Sediment samples from individual locations were tested for physical/chemical parameters only. The results of toxicological and bioaccumulation testing may be used by USACE to determine the amount of potential dredged material from Oakland Inner Harbor channel acceptable for open-water disposal as defined by the Draft Implementation Manual (EPA/USACE 1990) and consistent with the Water Resources Development Act of 1986 (Public Law 99-662). This is Volume 1 of a two-volume data report that presents the data gathered during the Oakland Harbor Phase 3 38-Foot Project, conducted in the Fall of 1990. This data report does not include interpretation or statistical analysis of the 38-Foot data. Volume 1 includes the project background as well as a full presentation of data and results in Appendixes A through H. Volume 2 contains the remaining data in Appendixes I through L
The future impact of changes in rate parity agreements on hotel chains: the long-term implications of the removal of rate parity agreements between hotels and online travel agents using closed consumer group booking models
The Office of Fair Trading, a not-for-profit and non-ministerial government department of the United Kingdom (from April 2014 incorporated within the Competition and Markets Authority), investigated the legality of rate parity from 2012, particularly rate parity agreements made between Intercontinental Hotel Group, Booking.com, and Expedia. Consequently, these major hotel brands and agents have committed to remove rate parity for closed consumer groups. This article identifies confusion over such groups and longer term implications. Smaller agents will enter the market, leading to increased fragmentation and competition. Branded hotels will face tough challenges in protecting prices and value from aggressive agents suddenly facing a more competitive market and independent hoteliers able to establish effective relationships with the new, smaller agents.
Keywords : Rate parity, pricing, closed consumer groups, hotels
The influence of medical expertise, case typicality and illness script component on case processing and disease probability estimates
The present study investigated the influence of medical expertise, case typicality, and illness script component (enabling conditions vs. consequences) on the speed of case informati
A population of luminous accreting black holes with hidden mergers
Major galaxy mergers are thought to play an important part in fuelling the
growth of supermassive black holes. However, observational support for this
hypothesis is mixed, with some studies showing a correlation between merging
galaxies and luminous quasars and others showing no such association. Recent
observations have shown that a black hole is likely to become heavily obscured
behind merger-driven gas and dust, even in the early stages of the merger, when
the galaxies are well separated (5 to 40 kiloparsecs). Merger simulations
further suggest that such obscuration and black-hole accretion peaks in the
final merger stage, when the two galactic nuclei are closely separated (less
than 3 kiloparsecs). Resolving this final stage requires a combination of
high-spatial-resolution infrared imaging and high-sensitivity hard-X-ray
observations to detect highly obscured sources. However, large numbers of
obscured luminous accreting supermassive black holes have been recently
detected nearby (distances below 250 megaparsecs) in X-ray observations. Here
we report high-resolution infrared observations of hard-X-ray-selected black
holes and the discovery of obscured nuclear mergers, the parent populations of
supermassive-black-hole mergers. We find that obscured luminous black holes
(bolometric luminosity higher than 2x10^44 ergs per second) show a significant
(P<0.001) excess of late-stage nuclear mergers (17.6 per cent) compared to a
sample of inactive galaxies with matching stellar masses and star formation
rates (1.1 per cent), in agreement with theoretical predictions. Using
hydrodynamic simulations, we confirm that the excess of nuclear mergers is
indeed strongest for gas-rich major-merger hosts of obscured luminous black
holes in this final stage.Comment: To appear in the 8 November 2018 issue of Nature. This is the
authors' version of the wor
WISE J233237.05–505643.5: A Double-peaked, Broad-lined Active Galactic Nucleus with a Spiral-shaped Radio Morphology
We present radio continuum mapping, optical imaging, and spectroscopy of the newly discovered double-peaked, broad-lined active galactic nucleus (AGN) WISE J233237.05–505643.5 at redshift z = 0.3447. This source exhibits an FR-I and FR-II hybrid morphology, characterized by a bright core, jet, and Doppler-boosted lobe structures in Australian Telescope Compact Array continuum maps at 1.5, 5.6, and 9 GHz. Unlike most FR-II objects, W2332–5056 is hosted by a disk-like galaxy. The core has a projected 5'' linear radio feature that is perpendicular to the curved primary jet, hinting at unusual and complex activity within the inner 25 kpc. The multi-epoch, optical-near-IR photometric measurements indicate significant variability over a 3-20 yr baseline from the AGN component. Gemini South optical data show unusual double-peaked emission-line features: the centroids of the broad-lined components of Hα and Hβ are blueshifted with respect to the narrow lines and host galaxy by ~3800 km s^(–1). We examine possible cases that involve single or double supermassive black holes in the system and discuss the required future investigations to disentangle the mysterious nature of this system
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