10,274 research outputs found
The Infra‐Red Spectrum of C2H6
The infra‐red spectrum of C2H6 gas has been studied in the region between 1.6 and 13μ with a spectrometer of high resolving power. From measurements on four resolved ∥ bands the value IB0 = (42.234±0.011)×10−40 g cm2 has been obtained for the large moment of inertia in the ground state. From measurements on the three fundamental ⊥ bands the best value at present available for the small moment of inertia is IA = 10.81×10−40 g cm2. Because of uncertainties concerning the perturbations of degenerate state ν8, of which a semi‐quantitative explanation which is apparently basically correct has been obtained, this value is provisional but appears to be fairly reliable. With these values of IB0 and IA, if one assumes C☒C = 1.55A, one obtains C☒H = 1.098A and ≰HCC = 109° 3′. From the considerations of the perturbations of state ν8 and of the frequencies and line spacings of the combination ⊥ bands, spectroscopic evidence indicating that the configuration of C2H6 is staggered (point group D3d) has for the first time been obtained. Also from these considerations the reliable value ν8 = 1472.2 cm−1 and the values ν4 = 290 cm−1 for the torsion frequency and ν12 = 1190 cm−1 for the ``uncertain'' frequency have been obtained. The latter two values are perhaps somewhat more reliable and not inconsistent with values obtained previously by other methods. These and other results are summarized in Figs. 1 and 14 and in Tables XII—XV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70901/2/JCPSA6-17-2-139-1.pd
Testing the use of marine protected areas to restore and manage tropical multispecies invertebrate fisheries at the Arnavon Islands, Solomon Islands : termination report
This report aimed to determine if the number and size of commercially important invertebrates (e.g. trochus, sea
cucumbers and giant clams) increases as the result of the declaration of the Arnavon Islands Marine
Conservation Area (MCA) relative to fished areas
Forty Years a Pioneer
"Through the entire book, there emerges the picture of a man of untarnished honor, of peculiar foresight, of strong will and of intense energy in bringing to pass things of which others only dreamed. In preserving the record of his father's active business life Mr. Baker has rendered a most useful public service.
The influence of the spectrum of jet turbulence on the stability, NOx emissions and heat release profile of pulverised coal flames.
The hypothesis investigated in the current study is that, increasing the scale of, and energy contained in, the larger scales of jet turbulence can beneficially influence the stability of pulverised fuel (PF) flames, their heat release profiles, and NO[subscript]x emissions. The hypothesis is investigated using precessing jet nozzles to enlarge the largest scales of turbulence and shift the energy in the spectrum of turbulence away from the fine scales. These effects are referred to as "enhanced large scale mixing" in the text.
Experiments were conducted to measure and compare the effects of a number of types of central jet, located within a co-annular stream, on the turbulent structure of the combined flow. Modelling was performed in water using a planar laser induced fluorescence visualisation technique, and limited to a region corresponding to the pre-ignition region of flames, where reasonable similarity exists. Individual fluid structures were tracked on successive video images. The effects of precession on jet half angles, convection velocities and characteristic strain rates were measured and compared with those of steady jets.
In a separate experiment, glass beads with particle size distributions similar to that of pulverised coal, were visualised in non-reacting air jets at ambient temperature, using a planar laser technique. The effects of large-scale structures, generated by centrally located precessing air flows, on particle motion and preferential concentration of particles in an annular jet were measured. Only the region corresponding to the pre-combustion region of flames was investigated since combustion is known to dramatically alter particle motion.
The effects of enhanced large scale mixing and particle clustering on PF flames were measured in two refractory lined kilns operated at 130 kW and 2.5 MW, respectively. A scaling parameter, which relates the effects of the dominant mechanisms on flame ignition distance was developed, and used to estimate the influence of enhanced large scale mixing at full scale. The dominant mechanisms, by which enhanced large scale mixing and particle clustering influences combustion, were assessed using sensitivity analyses.
It was demonstrated that large-scale particle clustering results from the promotion of the large scales of turbulence. These changes are shown to have potential to provide a means to simultaneously control NO[subscript]x emissions, and improve heat release and stability of PF flames in rotary kiln applications.Thesis (Ph.D.) -- Adelaide University, Dept. of Mechanical Engineering, 200
Anomalous light propagation and continuous lasing without inversion in an open driven -system
We explore a driven three-level -system coupled to an environment with
dynamics governed by the Lindblad master equation. We perform a transformation
into superoperator space, which brings the Lindblad equation into a
Schr\"{o}dinger-like, thus allowing us to obtain an exact analytical solution
for the time-dependence of the density matrix in a closed form. We demonstrate
a regime for continuous lasing without inversion for driving with a continuous
wave laser. We show a mechanism for achieving superluminal, negative, and
vanishing light pulse group velocities and provide a range of physical
parameters for realizing these regimes experimentally
Fitness Landscape of Antibiotic Tolerance in Pseudomonas aeruginosa Biofilms
Bacteria in biofilms have higher antibiotic tolerance than their planktonic counterparts. A major outstanding question is the degree to which the biofilm-specific cellular state and its constituent genetic determinants contribute to this hyper-tolerant phenotype. Here, we used genome-wide functional profiling of a complex, heterogeneous mutant population of Pseudomonas aeruginosa MPAO1 in biofilm and planktonic growth conditions with and without tobramycin to systematically quantify the contribution of each locus to antibiotic tolerance under these two states. We identified large sets of mutations that contribute to antibiotic tolerance predominantly in the biofilm or planktonic setting only, offering global insights into the differences and similarities between biofilm and planktonic antibiotic tolerance. Our mixed population-based experimental design recapitulated the complexity of natural biofilms and, unlike previous studies, revealed clinically observed behaviors including the emergence of quorum sensing-deficient mutants. Our study revealed a substantial contribution of the cellular state to the antibiotic tolerance of biofilms, providing a rational foundation for the development of novel therapeutics against P. aeruginosa biofilm-associated infections
Quantifying Catch Rates, Shark Abundance and Depredation Rate at a Spearfishing Competition on the Great Barrier Reef, Australia
We developed and applied a method to quantify spearfisher effort and catch, shark interactions and shark depredation in a boat-based recreational spearfishing competition in the Great Barrier Reef Marine Park in Queensland. Survey questions were designed to collect targeted quantitative data whilst minimising the survey burden of spearfishers. We provide the first known scientific study of shark depredation during a recreational spearfishing competition and the first scientific study of shark depredation in the Great Barrier Reef region. During the two-day spearfishing competition, nine vessels with a total of 33 spearfishers reported a catch of 144 fish for 115 h of effort (1.25 fish per hour). A subset of the catch comprised nine eligible species under competition rules, of which 47 pelagic fish were weighed. The largest fish captured was a 34.4 kg Sailfish (Istiophorus platypterus). The most common species captured and weighed was Spanish Mackerel (Scomberomorus commerson). The total weight of eligible fish was 332 kg and the average weight of each fish was 7.1 kg. During the two-day event, spearfishers functioned as citizen scientists and counted 358 sharks (115 h effort), averaging 3.11 sharks per hour. Grey Reef Sharks (Carcharhinus amblyrhynchos) comprised 64% of sightings. Nine speared fish were fully depredated by sharks as spearfishers attempted to retrieve their catch, which equates to a depredation rate of 5.9%. The depredated fish included four pelagic fish and five reef fish. The shark species responsible were Grey Reef Shark (C. amblyrhynchos) (66%), Bull Shark (Carcharhinus leucas) (11%), Whitetip Reef Shark (Triaenodon obesus) (11%) and Great Hammerhead (Sphyrna mokarran) (11%). There were spatial differences in fish catch, shark sightings and rates of depredation. We developed a report card that compared average catch of fish, sightings of sharks per hour and depredation rate by survey area, which assists recreational fishers and marine park managers to assess spatio-temporal changes. The participating spearfishers can be regarded as experienced (average 18 days a year for average 13.4 years). Sixty percent of interviewees perceived that shark numbers have increased in the past 10 years, 33% indicated no change and 7% indicated shark numbers had decreased. Total fuel use of all vessels was 2819 L and was equivalent to 6.48 tons of greenhouse gas emissions for the competition
Variations in follow-up services after inpatient stroke rehabilitation: A multicentre study
Background: Care after discharge from inpatient stroke rehabilitation units varies across Europe. The aim of this study was to compare service delivery after discharge. Methods: A total of 532 consecutive patients after stroke were recruited from 4 European rehabilitation centres in Germany, Switzerland, Belgium and the UK. At 2-month intervals, clinical assessments and structured interviews were carried out to document functional status and delivery of services after discharge. Significant factors for receiving follow-up services were analysed using a logistic generalized estimating equation model. Results: After controlling for case-mix, the results showed that Belgian patients were most likely to receive physical therapy but least likely to receive occupational therapy. German patients were least likely to receive nursing care. UK patients were less likely to receive medical care from their general practitioner compared with the other patient groups. Conclusion: Clinical characteristics did not explain the variations in service delivery after discharge from inpatient stroke rehabilitation. The decision-making processes involved in the provision of follow-up services need to be better documented. To improve our understanding of events post-discharge, the influence of non-clinical factors, such as healthcare regulations, should be explored further
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