Atomization Feature of Liquid-Column Tower

2012 ◽  
Vol 610-613 ◽  
pp. 1795-1800
Author(s):  
Li Jun Fang ◽  
Yan Chao Chang

A study was performed of the atomization feature of liquid-column tower. It was found that the broken droplets can be classified into three types which called convex,twisted and broken. Proposed that the atomization process of liquid column tower consist of impact atomization and run into a wall atomization. Analysis of the atomization mechanism of the two processes, and the run into a wall atomization have droplet rebound,expand,splash stages. In addition ,the high degree of atomization of theoretical formula was amended. After modified, the theoretical and actual values are basically consistent.

The measurement of small differences of pressure to a fairly high degree of accuracy is not difficult. I have indicated a construction of a micromanometer which in its ordinary commercial form has a range of 3 or 4 cm. of height of a liquid column and reads to 0·005 mm. direct. Dr. Stanton describes a manometer constructed on Professor Chattock’s principle, having a reading sensitiveness of 0·0015 mm. of water, but the range is not stated. Lord Bayleigh, observing the contact between mercury surfaces and sharp points, obtained a sensitiveness of 0·0005 mm. of mercury with a range of about 1·5 mm. The idea of employing the micro-manometer for the determination of the relative densities of gases first occurred to me in 1901 in considering the corrections to a set of Pitot tube observations taken in a gas pipe situated some 20 feet above the manometer, and though a rough trial was carried out at the time it is only recently that I have had an opportunity of making an adequate test of the method.


Author(s):  
Yuwei Wang ◽  
Xiao Han ◽  
Yuzhen Lin

Abstract Lean direct injection (LDI) combustion is one of the promising low pollution combustion technologies. One challenge of implementing LDI combustion is to achieve quick fuel-atomizing and mixing with air. In this paper, the spray characteristics and the prompt atomization process of the tangentially injected prefilming (TIP) LDI injector are investigated by experiments; the energy transmission model suitable for the prompt atomization process and the semi-empirical estimation model of SMD for the conical liquid film are derived. All experiments were carried out under 20°C and atmospheric pressure by using kerosene as the fuel. Firstly, effects of We and ALR on the spray distribution and SMD were studied by Mie scattering and Malvern spraytec laser diffraction system respectively, which were carried out at the operating conditions of We varying from 664 to 2656 and ALR varying from 16.3 to 24.5. Results show that large We is beneficial to disperse the spray in primary zone downstream the swirler. Then, breakup regimes of liquid film and droplets evolution were characterized by a high-speed camera with a long-distance microscope (LDM). Breakup regimes show that the film is torn up by the fierce outer airstream immediately. The primary breakup process does not rely on the surface waves anymore, which conforms to the prompt atomization mechanism. Finally, the energy transmission of the conical liquid film during the whole atomization process was analyzed, from which the semi-empirical estimation model of SMD was derived. The calculated and the measured SMD have good consistency, which demonstrates the applicability of the prompt atomization energy transmission model on a conical liquid film.


Author(s):  
Adrian F. van Dellen

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.


Author(s):  
Cecil E. Hall

The visualization of organic macromolecules such as proteins, nucleic acids, viruses and virus components has reached its high degree of effectiveness owing to refinements and reliability of instruments and to the invention of methods for enhancing the structure of these materials within the electron image. The latter techniques have been most important because what can be seen depends upon the molecular and atomic character of the object as modified which is rarely evident in the pristine material. Structure may thus be displayed by the arts of positive and negative staining, shadow casting, replication and other techniques. Enhancement of contrast, which delineates bounds of isolated macromolecules has been effected progressively over the years as illustrated in Figs. 1, 2, 3 and 4 by these methods. We now look to the future wondering what other visions are waiting to be seen. The instrument designers will need to exact from the arts of fabrication the performance that theory has prescribed as well as methods for phase and interference contrast with explorations of the potentialities of very high and very low voltages. Chemistry must play an increasingly important part in future progress by providing specific stain molecules of high visibility, substrates of vanishing “noise” level and means for preservation of molecular structures that usually exist in a solvated condition.


Author(s):  
P.R. Swann ◽  
A.E. Lloyd

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.


Author(s):  
J. M. Walsh ◽  
K. P. Gumz ◽  
J. C. Whittles ◽  
B. H. Kear

During a routine examination of the microstructure of rapidly solidified IN-100 powder, produced by a newly-developed centrifugal atomization process1, essentially two distinct types of microstructure were identified. When a high melt superheat is maintained during atomization, the powder particles are predominantly coarse-grained, equiaxed or columnar, with distinctly dendritic microstructures, Figs, la and 4a. On the other hand, when the melt superheat is reduced by increasing the heat flow to the disc of the rotary atomizer, the powder particles are predominantly microcrystalline in character, with typically one dendrite per grain, Figs, lb and 4b. In what follows, evidence is presented that strongly supports the view that the unusual microcrystalline structure has its origin in dendrite erosion occurring in a 'mushy zone' of dynamic solidification on the disc of the rotary atomizer.The critical observations were made on atomized material that had undergone 'splat-quenching' on previously solidified, chilled substrate particles.


Author(s):  
Willem H.J. Andersen

Electron microscope design, and particularly the design of the imaging system, has reached a high degree of perfection. Present objective lenses perform up to their theoretical limit, while the whole imaging system, consisting of three or four lenses, provides very wide ranges of magnification and diffraction camera length with virtually no distortion of the image. Evolution of the electron microscope in to a routine research tool in which objects of steadily increasing thickness are investigated, has made it necessary for the designer to pay special attention to the chromatic aberrations of the magnification system (as distinct from the chromatic aberration of the objective lens). These chromatic aberrations cause edge un-sharpness of the image due to electrons which have suffered energy losses in the object.There exist two kinds of chromatic aberration of the magnification system; the chromatic change of magnification, characterized by the coefficient Cm, and the chromatic change of rotation given by Cp.


Author(s):  
Robert F. Dunn

Receptor cells of the cristae in the vestibular labyrinth of the bullfrog, Rana catesbiana, show a high degree of morphological organization. Four specialized regions may be distinguished: the apical region, the supranuclear region, the paranuclear region, and the basilar region.The apical region includes a single kinocilium, approximately 40 stereocilia, and many small microvilli all projecting from the apical cell surface into the lumen of the ampulla. A cuticular plate, located at the base of the stereocilia, contains filamentous attachments of the stereocilia, and has the general appearance of a homogeneous aggregation of fine particles (Fig. 1). An accumulation of mitochondria is located within the cytoplasm basal to the cuticular plate.


Author(s):  
E. R. Macagno ◽  
C. Levinthal

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.


Author(s):  
T. A. Welton

An ultimate design goal for an improved electron microscope, aimed at biological applications, is the determination of the structure of complex bio-molecules. As a prototype of this class of problems, we propose to examine the possibility of reading DNA sequence by an imaginable instrument design. This problem ideally combines absolute importance and relative simplicity, in as much as the problem of enzyme structure seems to be a much more difficult one.The proposed technique involves the deposition on a thin graphite lamina of intact double helical DNA rods. If the structure can be maintained under vacuum conditions, we can then make use of the high degree of order to greatly reduce the work involved in discriminating between the four possible purine-pyrimidine arrangements in each base plane. The phosphorus atoms of the back bone form in projection (the helical axis being necessarily parallel to the substrate surface) two intertwined sinusoids. If these phosphorus atoms have been located up to a certain point on the molecule, we have available excellent information on the orientation of the base plane at that point, and can then locate in projection the key atoms for discrimination of the four alternatives.


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