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91.
Weber GH Dillard SE Carr H Pascucci V Hamann B 《IEEE transactions on visualization and computer graphics》2007,13(2):330-341
Topology provides a foundation for the development of mathematically sound tools for processing and exploration of scalar fields. Existing topology-based methods can be used to identify interesting features in volumetric data sets, to find seed sets for accelerated isosurface extraction, or to treat individual connected components as distinct entities for isosurfacing or interval volume rendering. We describe a framework for direct volume rendering based on segmenting a volume into regions of equivalent contour topology and applying separate transfer functions to each region. Each region corresponds to a branch of a hierarchical contour tree decomposition, and a separate transfer function can be defined for it. The novel contributions of our work are: 1) a volume rendering framework and interface where a unique transfer function can be assigned to each subvolume corresponding to a branch of the contour tree, 2) a runtime method for adjusting data values to reflect contour tree simplifications, 3) an efficient way of mapping a spatial location into the contour tree to determine the applicable transfer function, and 4) an algorithm for hardware-accelerated direct volume rendering that visualizes the contour tree-based segmentation at interactive frame rates using graphics processing units (GPUs) that support loops and conditional branches in fragment programs 相似文献
92.
GG Stone MM Chengappa RD Oberst NH Gabbert S McVey KJ Hennessy M Muenzenberger J Staats 《Canadian Metallurgical Quarterly》1993,5(3):378-385
The polymerase chain reaction was employed to correlate Salmonella serovars isolated from fecal material of greyhounds suffering from gastroenteritis with those isolated from the diet fed to the greyhounds prior to onset of diarrhea. Kennels around the Abilene, Kansas, area were contacted and supplied with materials needed to collect a portion of the diet each day. With the onset of diarrhea, the kennels were instructed to ship the fecal material and diet from the previous 10 days to the laboratory for testing. Forty-one fecal samples and corresponding diets were screened for Salmonella, Clostridium perfringens, Campylobacter jejuni, Staphylococcus aureus, Staphylococcus intermedius, and pathogenic (piliated) Escherichia coli by direct culture using standard procedures. The fecal material was also screened for coronavirus and parvovirus using electron microscopy. Thirty-five "normal" fecal samples were screened for all of the above mentioned microorganisms as a control. In addition, the fecal material was screened for E. coli verotoxins I and II and clostridial enterotoxins. A total of 61 Salmonella isolates were recovered from the 41 samples of feces and diet submitted for testing; 31 were recovered from the feces and 30 from the diet. Four Salmonella isolates were recovered from the normal fecal samples. Results obtained by PCR, plasmid profiles, antigenic analysis, and antibiogram profiles indicated that 16 of the 31 isolates recovered from the fecal material were the same strain as that recovered from the diet. 相似文献
93.
Jonathan Keller Damian Carr Frances Love Paul Grabill Hieu Ngo Perumal Shanthakumaran 《Journal of Intelligent Manufacturing》2012,23(2):205-211
The US Army has launched an aggressive program to implement condition based maintenance on its rotary wing assets. Condition
Based Maintenance takes advantage of technology developments in the areas of machinery monitoring, signal processing and fault
modeling to reduce the cost of ownership through improved maintenance procedures. Documenting the reduction in maintenance
burden, cost savings and increased safety through early detection of helicopter faults is an important step in justifying
the program. This paper describes a novel technique used to detect a serious fault in the accessory section of the AH-64D
Apache main transmission. The technique determines if the primary or secondary clutch system is driving the aircraft accessories
through a tachometer speed ratio. The method has identified three aircraft operating on the secondary system allowing Army
maintenance crews to replace the affected transmissions and quickly restore the aircraft to operational status. 相似文献
94.
95.
MM Guner 《Canadian Metallurgical Quarterly》1977,77(9):1300-1302
The results of hemoglobin determination in the CSF by the method of fluorescence microscopy in 195 patients speaks in favor of relative diagnostical importance of hemoglobin in the supra fall-out CSF for establishing the character of the stroke. The following circumstances testify to this fact: 1) in an artificial admixture of blood in the CSF in some cases there may be hemolysis of "passing" erythrocytes; 2) in a genuine admixture of blood, tests of hemoglobin in the centrifugate of the CSF may be negative since in some cases the transition of hemoglobin into bilirubin in the subarachmoid space occurs more rapidly than the hemolysis of erythrocytes. Thus, the hemoglobin does not accumulate in the liquid in quantities, sufficient enough to be measured by the existing methods; 3) in a large amount of artificial blood admixture, even without a hemolysis of "passing" erythrocytes the hemoglobin tests in the centrifugate of the CSF may be positive at the expense of hemoglobin of the blood plasma. 相似文献
96.
A histochemical technique has been used in scanning electron microscopy to localize specific areas in biological material. The specific contrast introduced by the staining procedure depends on the interaction of complex variables such as the coating material, the accelerating voltage and the use of a primary or secondary electron signal. 相似文献
97.
98.
Previous experimental results indicate that the humidification conditions at the anode have an impact on the liquid water distribution in the cathode gas diffusion layer. Numerical simulations are developed to reproduce and analyze this effect. Results consistent with the experimental results are first obtained by playing with the partition coefficients of an advanced pore network model computing the liquid water formation and transfer in the cathode gas diffusion layer (GDL) for a large range of operating conditions. Then, a model for the full anode – cathode assembly is developed by combining the pore network model of the cathode GDL and a 1D model describing the heat and water transfer in the various components of the anode-cathode assembly. This enables one to generalize the dry – wet regime diagram introduced in a previous work by incorporating the effect of the humidity condition at the anode. 相似文献
99.
M. E. Carr M. O. Bagby W. B. Roth 《Journal of the American Oil Chemists' Society》1986,63(11):1460-1464
The examination of plant species for their potential as renewable sources of industrial raw materials, conducted at the Northern
Regional Research Center, has been extended to include 110 species from North Dakota (ND), Colorado (CO), and Oregon (OR),
U.S.A. Plant samples were collected and analyzed for yields of “oil,” “polyphenol,” “hydrocarbon” and crude protein as well
as for botanical characteristics. Data are presented only for the relatively high-yielding species. Oil and hydrocarbon extracts
of plants that yielded at least 3.0% oil (dry, ash-free, plant sample basis) and/or at least 0.4% hydrocarbon were analyzed
for classes of constituents. Oils of such species were saponified to determine yields of fatty acids and unsaponifiable matter.
Hydrocarbon was examined for the presence of rubber, gutta and/or waxes. Polyisoprenes were analyzed for average molecular
weight and molecular weight distribution. Even when compared to about 1000 species previously analyzed in this program, seven
of the species yielded high amounts of oil (7.1–11.1%) plus substantial amounts of polyphenol (10.0–19.7%). Of these, six
are evergreen trees or shrubs and one is a nonwoody perennial. Another seven species yielded substantial amounts of oil (5.4–6.6%),
of which five gave 17.1–24.7% polyphenol. The most notable oil-producing species wereJuniperus scopulorum (11.1%),Pinus albicaulis (10.1%),Pinus flexilis (9.3%),Pinus mugo (8.4%),Liatris punctata (8.0%) andJuniperus communis (7.8%). Crude protein contents for all 22 species were low (4.2%) to moderate (10.4%). Maximum hydrocarbon content for the
22 selected species reported was only 0.5%. The highest total amount of oil, polyphenol, hydrocarbon and crude protein was
38.9% forAcer ginnala. Data obtained in this study are discussed with respect to those from species previously analyzed in this program. 相似文献
100.
Hydrodynamic and mass transfer data in Soltrol-130 (a mixture of C9+ iso-paraffins) were measured in a 0.305 m diameter bubble column. The gas holdup structure (i.e., the contributions to holdup from the small and large bubble fractions of the dispersion) for this hydrocarbon liquid in the churn turbulent flow regime was analyzed using the dynamic gas disengagement technique. The validity of the assumption of axially uniform gas holdup structure was checked. Literature correlations were found inadequate to explain the observed gas holdup and the volumetric mass transfer coefficients for Soltrol-130. The volumetric mass transfer coefficient per unit volume of large bubbles is shown to be independent of superficial gas velocity for the fully developed churn turbulent regime. The present hydrodynamic and mass transfer data in the churn turbulent regime should be useful in the design and scale-up of bubble columns used in organic process industries. 相似文献